U.S. patent application number 11/311277 was filed with the patent office on 2007-01-25 for resin particle liquid dispersion for electrostatic image developing toner, electrostatic image developing toner, production method thereof, developer and image forming method.
This patent application is currently assigned to FUJI XEROX CO., LTD.. Invention is credited to Satoshi Hiraoka, Yasuo Matsumura, Hirotaka Matsuoka, Fumiaki Mera, Yuki Sasaki.
Application Number | 20070020551 11/311277 |
Document ID | / |
Family ID | 37679434 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070020551 |
Kind Code |
A1 |
Sasaki; Yuki ; et
al. |
January 25, 2007 |
Resin particle liquid dispersion for electrostatic image developing
toner, electrostatic image developing toner, production method
thereof, developer and image forming method
Abstract
A resin particle liquid dispersion for an electrostatic image
developing toner, comprising: an aqueous medium; and a resin
particle dispersed in the aqueous medium to have a median diameter
of 0.05 to 2.0 .mu.m, the resin particle comprising a
polycondensable polymer obtained by polycondensing polycondensable
monomers, wherein a storage modulus GL(30) of the resin particle at
30.degree. C. is 1.times.10.sup.7 Pa or more, and a melting point
of the polycondensable polymer is from 45 to 110.degree. C.
Inventors: |
Sasaki; Yuki; (Kanagawa,
JP) ; Hiraoka; Satoshi; (Kanagawa, JP) ; Mera;
Fumiaki; (Kanagawa, JP) ; Matsuoka; Hirotaka;
(Kanagawa, JP) ; Matsumura; Yasuo; (Kanagawa,
JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
FUJI XEROX CO., LTD.
Tokyo
JP
|
Family ID: |
37679434 |
Appl. No.: |
11/311277 |
Filed: |
December 20, 2005 |
Current U.S.
Class: |
430/111.4 ;
430/123.52; 430/123.53; 430/137.14; 524/589 |
Current CPC
Class: |
C08G 63/52 20130101;
C08G 18/631 20130101; G03G 9/08768 20130101; C08G 63/16 20130101;
G03G 9/08795 20130101; G03G 9/0806 20130101; G03G 9/08797
20130101 |
Class at
Publication: |
430/111.4 ;
430/137.14; 430/124; 524/589 |
International
Class: |
G03G 9/08 20070101
G03G009/08; C08G 18/08 20060101 C08G018/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 20, 2005 |
JP |
2005-209848 |
Claims
1. A resin particle liquid dispersion for an electrostatic image
developing toner, comprising: an aqueous medium; and a resin
particle dispersed in the aqueous medium to have a median diameter
of 0.05 to 2.0 .mu.m, the resin particle comprising a
polycondensable polymer obtained by polycondensing polycondensable
monomers, wherein a storage modulus GL(30) of the resin particle at
30.degree. C. is 1.times.10.sup.7 Pa or more, and a melting point
of the polycondensable polymer is from 45 to 110.degree. C.
2. The resin particle liquid dispersion for an electrostatic image
developing toner according to claim 1, wherein change in a storage
modulus of the resin particle from 10.sup.6 Pa to 10.sup.4 Pa
occurs by a temperature change within 10.degree. C.
3. The resin particle liquid dispersion for an electrostatic image
developing toner according to claim 1, wherein change in a storage
modulus of the resin particle from 10.sup.7 Pa to 10.sup.3 Pa
occurs by a temperature change within 20.degree. C.
4. The resin particle liquid dispersion for an electrostatic image
developing toner according to claim 1, wherein when a common
logarithm of the storage modulus of the resin particles is plotted
with respect to temperature, assuming that a melting point of the
resin particle is Tm, a storage modulus at Tm+20.degree. C. is
G'(Tm+20), and a storage modulus at Tm+50.degree. C. is G'(Tm+50),
condition of the following formula (1) is satisfied: |log
G'(Tm+20)-log G'(Tm+50)|.ltoreq.1.5 (1)
5. The resin particle liquid dispersion for an electrostatic image
developing toner according to claim 1, wherein a constitutional
ratio of at least one of: an unsaturated bond-containing carboxylic
acid; its acid anhydride; and its lower ester is from 20.0 to 50.0
wt % based on all monomers constituting the resin particle.
6. The resin particle liquid dispersion for an electrostatic image
developing toner according to claim 1, wherein the resin particle
has an acid value of 1 to 50 mgKOH/g.
7. The resin particle liquid dispersion for an electrostatic image
developing toner according to claim 1, wherein the resin particle
has a glass transition temperature Tg of from 40 to 100.degree.
C.
8. The resin particle liquid dispersion for an electrostatic image
developing toner according to claim 1, wherein a constitutional
ratio of a polyisocyanate having 1.5 or more isocyanate groups on
average within one molecule is from 20.0 to 90.0 wt % based on all
monomers constituting the resin particle.
9. A method for producing the resin particle liquid dispersion for
an electrostatic image developing toner according to claim 1, the
method comprising: preparing an emulsified liquid dispersion
comprising an aqueous medium and an oil phase comprising at least
polycondensable monomers, the oil phase being dispersed in the
aqueous medium; and polycondensing the polycondensable
monomers.
10. The method for producing a resin particle liquid dispersion for
an electrostatic image developing toner according to claim 9,
wherein assuming that a melting point of the resin particle is Tm,
a polycondensation temperature Tc satisfies (Tm-20.degree.
C.)<Tc<(Tm+20.degree. C.),
11. The method for producing a resin particle liquid dispersion for
an electrostatic image developing toner according to claim 9,
wherein assuming that the highest temperature out of melting points
of the polycondensable monomers is Th, the polycondensation
temperature Tc satisfies 45.degree. C.<Tc<Th.
12. The method for producing a resin particle liquid dispersion for
an electrostatic image developing toner according to claim 9, the
method further comprising rapidly cooling the resin particle liquid
dispersion to a temperature of --10.degree. C. or more and
Tc-60.degree. C. or less at 2.degree. C./min or more after the
polycondensing.
13. A method for producing an electrostatic image developing toner,
comprising: aggregating resin particles in a liquid dispersion
comprising at least a resin particle liquid dispersion to obtain
aggregate particles; and heating and coalescing the aggregate
particles, wherein the resin particle liquid dispersion is a resin
particle liquid dispersion for an electrostatic image developing
toner according to claim 1.
14. A method for producing an electrostatic image developing toner,
comprising aggregating resin particles in a liquid dispersion
comprising at least a resin particle liquid dispersion to obtain
aggregate particles; and heating and coalescing the aggregate
particles, wherein the resin particle liquid dispersion is a resin
particle liquid dispersion for an electrostatic image developing
toner produced by a method according to claim 9.
15. An electrostatic image developer comprising an electrostatic
image developing toner obtained by a method using a resin particle
liquid dispersion for an electrostatic image developing toner
according to claim 1; and a carrier.
16. An image forming method comprising: forming an electrostatic
latent image on a surface of a latent image-holding member;
developing the electrostatic latent image formed on the surface of
the latent image-holding member with a developer containing a toner
to form a toner image; transferring the toner image formed on the
surface of the latent image-holding member to a surface of a
transferee member; and heat-fixing the toner image transferred to
the surface of the transferee member, wherein the toner is the
electrostatic image developing toner obtained by a method for
producing an electrostatic image developing toner according to
claim 14.
17. An image forming method comprising: forming an electrostatic
latent image on a surface of a latent image-holding member;
developing the electrostatic latent image formed on the surface of
the latent image-holding member with a developer containing a toner
to form a toner image; transferring the toner image formed on the
surface of the latent image-holding member to a surface of a
transferee member; and heat-fixing the toner image transferred to
the surface of the transferee member, wherein the developer is the
electrostatic image developer according to claim 15.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a resin particle liquid
dispersion for an electrostatic image developing toner excellent in
various properties such as color formability and OHP transparency
and suitably usable for forming an image by an electrophotographic
process, an electrostatic recording process or the like, a toner
using the resin particle liquid dispersion, production processes
thereof, a developer using the toner and an image forming
method.
[0003] 2. Description of the Related Art
[0004] With rapid spread of digitization technology, high image
quality is currently demanded for the output such as print and copy
by users at the home or office or in the publishing field. In order
to meet this requirement for high image quality, the toner for use
particularly in electrophotography is reduced in the particle
diameter with an attempt to enhance the resolution, and the
particle diameter is at present reduced even to the region of 5
.mu.m. In this case, in view of production energy and cost,
reduction in the toner particle diameter can be hardly attained by
a kneading-pulverization method conventionally employed for the
production of toner, and the trend is now shifting to a technique
of preparing a resin particle liquid dispersion by a so-called
chemical production process in an aqueous medium, such as
suspension-polymerization, dissolution-suspension or emulsion
polymerization-aggregation, and granulating the resin particle
liquid dispersion to produce a toner.
[0005] In general, control of particle diameter and particle
diameter distribution of toner particles is indispensable for a
toner so as to obtain a high-quality image. A toner produced
particularly by a kneading-pulverization or
suspension-polymerization method having a tendency of bringing
about a broad particle diameter distribution passes through a
classification step to obtain toner particles having a desired
particle diameter and therefore, the yield is liable to
decrease.
[0006] With respect to the method for polymerizing a resin in an
aqueous medium, a suspension-polymerization method, a
dissolution-suspension method and an emulsion
polymerization-aggregation method are generally employed at
present. As for the emulsion polymerization, the polymerization of
monomers by using a surfactant in an amount less than the critical
micelle concentration (CMC) and a co-surfactant in combination in
the presence of a polymerization initiator for the monomer emulsion
is particularly known as so-called "miniemulsion polymerization"
which is described, for example, in P. L. Tang, E. D. Sudol, C. A.
Silbi and M. S. El-Aasser, J. Appl. Polym. Sci., Vol. 43, page 1059
(1991).
[0007] The conventional emulsion polymerization method is a method
of polymerizing an aqueous emulsion of monomer particles having a
particle diameter of about several .mu.m by using a water-soluble
polymerization initiator in the presence of a surfactant not less
than the critical micelle concentration (CMC). In the conventional
method, the polymerization is initiated in a surfactant micelle and
a monomer is diffused and supplied from the monomer particle to
grow and form polymer particles.
[0008] On the other hand, the miniemulsion polymerization method is
advantageous in that since a monomer is polymerized in the monomer
particle, migration (e.g., diffusion) of a substance is not
involved, and polymer particles uniform in the shape and properties
can be formed. That is, in the miniemulsion polymerization method,
the diameter of polymer particles can be controlled by controlling
the liquid droplet size of a monomer liquid dispersion.
[0009] Examples of the invention relating to a toner produced by
using such a miniemulsion polymerization method include the
followings. For example, JP-A-2001-290308 discloses a production
process of an electrostatic image developing toner, comprising
aggregating colorant-containing polymer particles obtained by
miniemulsion polymerization of a monomer and a colorant.
JP-A-2002-49180 discloses a toner obtained by salting-out/fusing
resin particles produced through multi-step polymerization, where
the resin particle except for the outermost layer contains a resin
particle produced by using miniemulsion polymerization. These
studies all are made on the toner production process involving a
radical polymerization reaction by miniemulsion polymerization.
[0010] In Mattheineu Barrere and Kaharins Landfester, Polymer.,
Vol. 44, page 2833 (2003), the results when a polyester is
polycondensed from a dodecane diacid and a dodecane diol or the
like in water are described. However, in this and other research
papers, there is not found a case of studying on physical
properties of a polycondensed resin particle obtained by a
miniemulsion polymerization method or on a technique for obtaining
a polycondensable polymer having specific physical properties.
Needless to say, a case of studying on the application of a
miniemulsion polymerization method comprising a polycondensation
reaction to the production of a toner is not found.
[0011] Also, with the increasing demand to save energy necessary
for the image formation, the toner fixing temperature must be more
lowered so as to realize power saving at the fixing step. When the
toner fixing temperature is lowered, in addition to power saving,
the waiting time until the fixing member surface reaches the fixing
possible temperature after turning on the power source, so-called
warm-up time, can be shortened and the life of the fixing member
can be prolonged.
[0012] For lowering the toner fixing temperature, a method of
decreasing the glass transition point of a toner particle is
generally employed. However, if the glass transition temperature is
excessively lowered, aggregation (blocking) of powder particles
readily occurs or preservability of the toner on the fixed image is
lost (generally called "document offset"), and lowering of the
toner fixing temperature and preservability of the toner can be
hardly attained at the same time. In order to attain both
low-temperature fixing and toner preservability, a so-called
sharp-melt property of causing abrupt decrease in the viscosity of
the toner in a high-temperature region must be imparted while
keeping the glass transition point of the toner at a higher
temperature.
[0013] However, the resin used for the toner usually has a certain
width in the glass transition point, molecular weight or the like
and therefore, the composition and molecular weight of the resin
must be made extremely uniform so as to obtain a sharp-melt
property. For obtaining such a resin, it is necessary to use a
special production process or adjust the molecular weight of the
resin by subjecting the resin to a treatment such as
chromatography. In this case, the cost inevitably rises or an
unnecessary resin (waste) is yielded at the production of a highly
uniform resin and this is not preferred also from the aspect of
environmental protection awareness in recent years.
[0014] Accordingly, a toner for electrophotography having a low
fixing temperature and a sharp-melt property and causing no offset
even in a high-temperature region is keenly demanded.
[0015] In general, as means for satisfying all of blocking
inhibition, image preservability and low-temperature fixing, a
method of using a crystalline resin as the binder resin has long
been known (see, for example, JP-B-4-24702). The crystalline resin
has a melting point to afford great decrease in the viscosity at a
specific temperature, and the temperature difference between the
start of thermal activity of a resin molecule and the fixing
possible region can be made small, so that an excellent
low-temperature fixing property can be imparted. On the other hand,
in the case of a non-crystalline resin, the viscosity gradually
decreases after the resin molecule starts its thermal activity at
the glass transition point, and the temperature difference until
the fixing possible region is large, as result, a low-temperature
fixing property cannot be ensured. In the crystalline resin, the
viscosity tends to continuously decrease even at a temperature
higher than the melting point, and the melted toner permeates into
paper to provide an effect of preventing generation of offset, but
excessive permeation of the melted toner into paper
disadvantageously occurs to cause a problem that an image with
uniform and high density cannot be obtained. Furthermore, the
crystalline resin has insufficient hardness at normal temperature
and, for example, this may allow for deformation of the toner
particle on mixing with a carrier in a developing machine or
deformation of the toner particle by the shear force imposed from a
cleaning blade, giving rise to deleterious change of
electrification cleaning failure or insufficient strength of the
produced image.
[0016] In order to solve these problems, many techniques of using a
crystalline polymer as the binder resin in combination with a
non-crystalline polymer have been proposed. For example,
JP-A-2001-42564 proposes a technique of fusing resin particles
containing a crystalline substance and an amorphous polymer, in an
aqueous medium. However, in this invention, a crystalline polyester
resin is produced by a conventional method. Generally, in the case
where a polyester resin produced through polycondensation at a high
temperature of 150.degree. C. or more is used for the chemical
process toner, there is a problem that a huge energy is necessary
to disperse and emulsify the once bulk-polymerized resin to a toner
diameter, the use and recovery of an organic solvent requires a
large-scale facility investment, or the obtained resin particle
liquid dispersion suffers from a board resin particle diameter
distribution. Furthermore, in the above-described method, it is
difficult to effect aggregation and coalescence of the toner by
mixing a latex containing a crystalline substance with a latex
containing an amorphous substance. This is ascribable to the
difference between the surface electric charge of the crystalline
polyester latex and the surface electric charge of the vinyl-based
latex.
[0017] Similarly, JP-A-2004-191927 discloses an electrostatic image
developing toner comprising a crystalline polyester as the binder
resin and an amorphous polymer, the toner surface being covered
with a surface layer mainly comprising the amorphous polymer,
wherein the crystalline polyester content is from 30 to 80 wt %,
the proportion of the crystalline polyester contained in the
outermost surface of the electrostatic image developing toner is 15
atomic % or less, and the average thickness of the surface layer is
from 0.01 to 0.5 .mu.m. However, this toner is produced by mixing
an amorphous polymer liquid dispersion and a crystalline polyester
liquid dispersion at the aggregation step, and uneven distribution
of constituent components is liable to occur during aggregation.
Furthermore, the method of producing the crystalline polyester
liquid dispersion has a problem that a high energy is necessary as
described above or the production process is long and
complicated.
[0018] Also, many techniques of using a polymer obtained by
chemically bonding a crystalline polymer and a non-crystalline
polymer have been invented. Examples thereof include
JP-A-2004-233983. This invention is a toner comprising a resin
formed by reacting an epoxy group of an epoxy group-containing
vinyl resin with a carboxyl group of a resin containing a polyester
unit and a carboxyl group, wherein the toner has a specific
viscoelasticity. However, since a reaction process at a high
temperature is necessary for obtaining resin particles by this
production process as in conventional techniques and the toner is
produced by a melting-kneading production process, the energy
consumption is large and the obtained toner has a hardly alignable
shape and a broad particle diameter distribution. JP-A-2001-117268
also discloses a toner comprising a crystalline polyester having a
polymerization crosslinked structure introduced by a radical
reaction of unsaturated bonds, but the toner produced by suspension
polymerization has a broad particle diameter distribution and
therefore, high image quality is hardly obtained. Furthermore, the
polycondensation reaction is based on a conventional method and
requires a high energy.
[0019] In this way, as for the toner using a crystalline resin, it
is difficult to achieve low-energy production of a toner
successfully controlled in the viscoelasticity, electrostatic
property, toner particle diameter and particle diameter
distribution. Also, in the mixing of a crystalline resin and a
non-crystalline resin, various contradictory properties are
required to satisfy at the same time, and a toner satisfied in
these and other toner properties such as powder fluidity and
coloring property is not provided at present.
SUMMARY OF THE INVENTION
[0020] The present invention provides a resin particle liquid
dispersion for an electrostatic image developing toner, in which
resin particles having a viscoelasticity, a particle diameter and a
particle diameter distribution suitable for a toner are dispersed.
Also, the present provides a method for producing an electrostatic
image developing toner by utilizing the resin particle liquid
dispersion, in which not only enhanced fixing property and high
image quality are obtained but also a simple process requiring a
low energy is ensured.
[0021] The above-described objects of the present invention can be
attained by the following <1> to <6>.
[0022] <1> A resin particle liquid dispersion for an
electrostatic image developing toner, comprising: an aqueous
medium; and a resin particle dispersed in the aqueous medium to
have a median diameter of 0.05 to 2.0 .mu.m, the resin particle
comprising a polycondensable polymer obtained by polycondensing
polycondensable monomers, wherein a storage modulus GL(30) of the
resin particle at 30.degree. C. is 1.times.10.sup.7 Pa or more, and
a melting point of the polycondensable polymer is from 45 to
110.degree. C.
[0023] <2> A method for producing the resin particle liquid
dispersion for an electrostatic image developing toner described in
<1>, comprising: a step of preparing an emulsified liquid
dispersion comprising an aqueous medium and an oil phase comprising
at least polycondensable monomers, the oil phase being dispersed in
the aqueous medium; and a step of polycondensing the
polycondensable monomers.
[0024] <3> A method for producing an electrostatic image
developing toner, comprising: a step of aggregating resin particles
in a liquid dispersion containing at least a resin particle liquid
dispersion to obtain aggregate particles; and a step of heating and
coalescing the aggregate particles, wherein the resin particle
liquid dispersion is a resin particle liquid dispersion for an
electrostatic image developing toner described in <1> above
or a resin particle liquid dispersion for an electrostatic image
developing toner produced by the production method described in
<2> above.
[0025] <4> An electrostatic image developing toner obtained
by the production method described in <3> above.
[0026] <5> An electrostatic image developer comprising: the
electrostatic image developing toner described in <4> above;
and a carrier.
[0027] <6> An image forming method comprising a latent
image-forming step of forming an electrostatic latent image on the
surface of a latent image-holding member, a development step of
developing the electrostatic latent image formed on the surface of
the latent image-holding member with a developer containing a toner
to form a toner image, a transfer step of transferring the toner
image formed on the surface of the latent image-holding member to
the surface of a transferee member, and a fixing step of
heat-fixing the toner image transferred to the surface of the
transferee member, wherein the toner is the electrostatic image
developing toner described in <4> above or the developer is
the electrostatic image developer described in <5> above.
DETAILED DESCRIPTION OF THE INVENTION
[0028] That is, the present invention relates to a resin particle
liquid dispersion having dispersed therein resin particles
containing a polycondensable polymer having specific properties
obtained by polycondensing polycondensable monomers in an aqueous
medium. The toner produced by using this resin particle liquid
dispersion not only ensures enhanced fixing property and high image
quality but also can be produced by a simple process with low
energy.
[0029] The present invention is described in detail below.
(Resin Particle Liquid Dispersion for Electrostatic Image
Developing Toner)
[0030] The resin particle liquid dispersion for an electrostatic
image developing toner of the present invention (hereinafter
sometimes simply referred to as a "resin particle liquid
dispersion") is a resin particle liquid dispersion where resin
particles containing a polycondensable polymer (hereinafter
sometimes referred to as a "polycondensed resin") obtained by
polycondensing polycondensable monomers in an aqueous medium are
dispersed to have a median diameter of 0.5 to 2.0 .mu.m in an
aqueous medium, and is characterized in that the storage modulus
GL(30) at 30.degree. C. of the resin particle is 1.times.10.sup.7
Pa or more and the melting point of the polycondensable polymer is
from 45 to 110.degree. C. The resin particle liquid dispersion of
the present invention is preferably produced by the production
process of a resin particle liquid dispersion, which is described
later.
[0031] The median diameter (center diameter) of the resin particle
in the resin particle liquid dispersion of the present invention is
from 0.05 to 2.0 .mu.m, preferably from 0.1 to 1.5 .mu.m, more
preferably from 0.1 to 1.0 .mu.m.
[0032] Such dispersion can be attained by effecting uniform mixing
and emulsion-dispersion in a shear mixing apparatus such as piston
homogenizer, microfluidizing device (for example, "Microfluidizer"
manufactured by Microfluidics) and ultrasonic disperser. If the
median diameter of the resin particle is too small, the aggregating
property at the formation of particles changes for the worse to
readily generate isolated resin particles or the viscosity of the
system tends to increase, which makes it difficult to control the
particle diameter. On the other hand, if the median diameter is
excessively large, the particle formation is readily associated
with generation of coarse powder to worsen the particle size
distribution and at the same time, isolation of the releasing agent
such as wax is liable to occur, giving rise to reduction in the
releasability at the fixing or in the offset-generating
temperature.
[0033] The median diameter of the resin particle can be measured,
for example, by a Coulter counter (TA II, Manufactured by Beckman
Coulter Inc.).
[0034] The storage modulus GL(30) at an angular frequency of 1
rad/sec and 30.degree. C. of the resin particle of the present
invention is 1.times.10.sup.7 Pa or more, preferably from
1.times.10.sup.7 to 1.times.10.sup.11, more preferably from
1.times.10.sup.7 to 5.times.10.sup.1. If the storage modulus GL(30)
is less than 1.times.10.sup.7 Pa, for example, in the case of a
two-component developing system, the toner particle is deformed by
the pressure or shear force imposed from the carrier when mixed
with a carrier in a developing machine and fails in stably
maintaining the electrostatic developing property, or the toner
particle is deformed by the shear force imposed from a cleaning
blade at the cleaning of toner on an electrostatic latent
image-supporting member and this may cause a cleaning failure.
Furthermore, the toner storability may be worsened, particularly,
aggregation of toners with each other (blocking phenomenon) may
occur during storage at a high temperature and a high humidity.
[0035] In the present invention, change in the storage modulus of
the resin particle from 10.sup.6 Pa to 10.sup.4 Pa preferably
occurs by a temperature change within 15.degree. C., more
preferably within 10.degree. C. When the temperature change is in
this range, the so-called sharp-melt property is high, so that
fixing can be performed at a low temperature, a satisfactory effect
of reducing the energy consumption can be obtained, and the fixing
latitude can be sufficiently broad.
[0036] Furthermore, in the present invention, change in the storage
modulus of the resin particle from 10.sup.7 Pa to 10.sup.3 Pa
preferably occurs by a temperature change within 25.degree. C.,
more preferably within 20.degree. C. This change in the storage
modulus corresponds to the change in viscosity and means that
change from the viscosity where the attachment of toner can be
controlled or the strength of toner can be maintained, to the
viscosity necessary for fixing can be realized within the
above-described temperature range. When a sufficiently large
viscosity change is obtained by the temperature change in the
above-described range, the sharp-melt property and the
low-temperature fixing property are satisfied and this is
preferred.
[0037] In the resin particle for use in the present invention,
assuming that the melting point of the resin particle is Tm, the
storage modulus at Tm+20.degree. C. is G'(Tm+20), and the storage
modulus at Tm+50.degree. C. is G'(Tm+50), the condition of the
following formula (1) is satisfied: |log G'(Tm+20)-log
G'(Tm+50)|.ltoreq.1.5 (1)
[0038] This index indicates that the temperature dependency of the
storage modulus after the melting point is low. More specifically,
the resin particle in the resin particle liquid dispersion of the
present invention expresses abrupt decrease in the elastic modulus
at the melting point and thereafter, the elastic modulus is
stabilized in a predetermined range, so that penetration into paper
or offset can be prevented because even when the temperature is
elevated at the fixing, the viscosity does not excessively
decrease.
[0039] The viscoelasticity (storage modulus) can be obtained by
shaping the resin particle into a tablet and measuring it with use
of a rotary plate-type rheometer (RDA, 2RHIOS SYSTEM ver. 4.3.2,
manufactured by Rheometric Scientific F.E. Ltd.) or the like.
[0040] The melting point of the resin particle usable in the
present invention is preferably from 45 to 110.degree. C., more
preferably from 50 to 100.degree. C., and most preferably from 55
to 90.degree. C. The viscosity of the toner abruptly decreases on
reaching the melting point and therefore, if the toner is stored in
a temperature environment higher than the melting point, blocking
occurs. Accordingly, the melting point of the toner is preferably
higher than the lower temperature limit in a normal
high-temperature environment to which the toner after storage or
image formation is exposed, that is 45.degree. C. or more. When the
melting point is 110.degree. C. or less, the toner can have an
excellent low-temperature fixing property and this is
preferred.
[0041] The melting point can be obtained as a melting peak
temperature of the input compensation differential scanning
calorimetry according to JIS K 7121: 87. Incidentally, the
crystalline resin sometimes has a plurality of melting peaks, but
the maximum peak is regarded as the melting point.
<Polycondensable Monomer>
[0042] The polycondensable monomer which can be used in the present
invention is not particularly limited and any polycondensable
monomer may be used as long as it is used for various
polymerization methods described later. The polycondensable monomer
is described in detail below.
[0043] The polycondensable monomer which can be used in the present
invention is not particularly limited if it is a substance of
forming a crystalline polymer, and either a monomer of forming a
crystalline polymer or a monomer of forming a non-crystalline
polymer may be used, but a monomer of forming a crystalline polymer
is preferred. Examples of the polycondensable monomer include those
using an aliphatic, alicyclic or aromatic polyvalent carboxylic
acid or an alkyl ester thereof, a polyhydric alcohol or an ester
compound thereof, or a polyvalent amine. Such monomers can be
directly polymerized by an esterification reaction, an
transesterification reaction or the like.
[0044] The polyvalent carboxylic acid is a compound containing two
or more carboxyl groups within one molecule. Out of these
compounds, a dicarboxylic acid is a compound containing two
carboxyl groups within one molecule and examples thereof include an
oxalic acid, a succinic acid, a maleic acid, a malonic acid, a
glutaric acid, an adipic acid, a methyladipic acid, an azelaic
acid, a sebacic acid, a nonanedicarboxylic acid, a
decanedicarboxylic acid, an undecanedicarboxylic acid, a
dodecanedicarboxylic acid, a fumaric acid, a citraconic acid, an
itaconic acid, a diglycolic acid, a
cyclohexane-3,5-diene-1,2-carboxylic acid, a malic acid, a citric
acid, a hexahydroterephthalic acid, a malonic acid, a pimelic acid,
a tartaric acid, a mucic acid, a phthalic acid, an isophthalic
acid, a terephthalic acid, a tetrachlorophthalic acid, a
chlorophthalic acid, a nitrophthalic acid, a p-carboxyphenylacetic
acid, a p-phenylenediacetic acid, an m-phenylenediglycolic acid, a
p-phenylenediglycolic acid, an o-phenylenediglycolic acid, a
diphenylacetic acid, a diphenyl-p,p'-dicarboxylic acid, a
naphthalene-1,4-dicarboxylic acid, a naphthalene-1,5-dicarboxylic
acid, a naphthalene-2,6-dicarboxylic acid and an anthracene
dicarboxylic acid. Examples of the polyvalent carboxylic acid other
than the dicarboxylic acid include a trimellitic acid, a trimesic
acid, a pyromellitic acid, a naphthalenetricarboxylic acid, a
naphthalenetetracarboxylic acid, a pyrenetricarboxylic acid and a
pyrenetetracarboxylic acid.
[0045] Among these polyvalent carboxylic acids, preferred as the
polycondensable monomer usable in the present invention are an
azelaic acid, a sebacic acid, a 1,9-nonane-dicarboxylic acid, a
1,10-decanedicarboxylic acid, a 1,11-undecanedicarboxylic acid, a
1,12-dodecanedicarboxylic acid, a trimellitic acid and a
pyromellitic acid. Since these polyvalent carboxylic acids are
sparingly soluble or insoluble in water, the polycondensation
reaction proceeds in an oil droplet formed by dispersing a
polyvalent carboxylic acid in water and this is preferred.
[0046] The polyhydric alcohol (polyol) which can be used in the
present invention is a compound having two or more hydroxyl groups
within one molecule. Out of these compounds, the diol is a compound
having two hydroxyl groups within one molecule and examples thereof
include ethylene glycol, diethylene glycol, triethylene glycol,
propylene glycol, butanediol, butenediol, neopentyl glycol, pentane
glycol, hexanediol, cyclohexanediol, cyclohexanedimethanol,
dipropylene glycol, octanediol, nonanediol, decanediol,
dodecanediol, bisphenol A, bisphenol Z and hydrogenated bisphenol
A. Examples of the polyol other than the diol include, but are not
limited to, glycerin, pentaerythritol, hexamethylolmelamine,
hexaethylolmelamine, tetramethylolbenzoguanamine and
tetraethylolbenzoguanamine.
[0047] Among these polyols, preferred as the polyol usable in the
present invention are diols such as 1,6-hexanediol, 1,8-octanediol,
1,9-nonanediol, 1,10-decanediol and 1,12-dodecanediol. Preferred
examples of the polyol other than the divalent polyol include
glycerin, pentaerythritol, hexahydroxymethylmelamine,
hexahydroxyethylmelamine, tetra-hydroxymethylbenzoguanamine and
tetrahydroxyethylbenzoguanamine.
[0048] The polycondensation may also be performed by using a
substance containing a carboxylic acid and a hydroxyl group within
one molecule, and examples of such a substance include, but are not
limited to, a hydroxyoctanoic acid, a hydroxynonanoic acid, a
hydroxydecanoic acid, a hydroxyundecanoic acid, a hydroxydodecanoic
acid, a hydroxytetradecanoic acid, a hydroxytridecanoic acid, a
hydroxyhexadecanoic acid, a hydroxypentadecanoic acid and a
hydroxystearic acid.
[0049] By the combination of these polycondensable monomers, a
non-crystalline resin or a crystalline resin can be easily
obtained, but a crystalline polymer or a crystalline polyamide is
preferred, and a crystalline polyester is more preferred.
[0050] Among such crystalline polyesters, in view of suitability
for a toner, preferred are a combination of hexanediol with an acid
selected from an adipic acid, a sebacic acid and a
1,10-decanedicarboxylic acid (dodecane diacid), a combination of
octanediol with an acid selected from an adipic acid and a sebacic
acid, a combination of octanediol with an acid selected from an
adipic acid and a sebacic acid, and a combination of nonanediol
with an adipic acid, a sebacic acid or a 1,10-decanedicarboxylic
acid (dodecane diacid).
[0051] Examples of the polyamine used for obtaining a polyamide
include ethylenediamine, diethylenediamine, triethylenediamine,
1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine,
1,4-butenediamine, 2,2-dimethyl-1,3-butanediamine,
1,5-pentanediamine, 1,6-hexanediamine, 1,4-cyclohexanediamine and
1,4-cyclohexanebis(methylamine).
[0052] By the combination of these polyamines, a non-crystalline
resin or a crystalline resin can also be easily obtained, but a
crystalline resin is preferred.
[0053] Examples of the polycondensation catalyst which can be used
in the present invention include a surfactant-type catalyst, a
metal catalyst and a hydrolase-type catalyst.
[0054] The surfactant-type catalyst includes, for example, a strong
acid having a surface activating effect, and examples of the strong
acid which can be used include, but are not limited to, an
alkylbenzenesulfonic acid such as dodecylbenzenesulfonic acid,
isopropylbenzenesulfonic acid, comphorsulfonic acid and
para-toluenesulfonic acid, an alkylsulfonic acid, an
alkyldisulfonic acid, an alkylphenolsulfonic acid, an
alkylnaphthalenesulfonic acid, an alkyltetralinsulfonic acid, an
alkylallylsulfonic acid, a petroleum sulfonic acid, an
alkylbenzimidazolesulfonic acid, a higher alcohol ether sulfonic
acid, an alkyldiphenylsulfonic acid, a long-chain alkylsulfuric
acid ester such as monobutyl-phenylphenol sulfate,
dibutyl-phenylphenol sulfate and dodecyl sulfate, a higher alcohol
sulfuric acid ester, a higher alcohol ether sulfuric acid ester, a
higher fatty acid amide alkylol sulfuric acid ester, a higher fatty
acid amide alkylated sulfuric acid ester, a naphthenyl alcohol
sulfuric acid, a sulfated fat, a sulfosuccinic acid ester, various
fatty acids, a sulfonated higher fatty acid, a higher
alkylphosphoric acid ester, a resin acid, a resin acid alcohol
sulfuric acid, a naphthenic acid, a niobic acid, and salt compounds
of all of these acids, such as a salt compound with a rare earth
metal described below. A plurality of these acids and compounds may
be used in combination, if desired. Among these surfactant-type
catalysts, preferred are a dodecylbenzenesulfonic acid, an
isopropylbenzenesulfonic acid and a comphorsulfonic acid.
[0055] Examples of the metal catalyst include, but are not limited
to, an organic tin compound, an organic titanium compound, an
organic tin halide compound and a rare earth metal catalyst. As for
the rare earth-containing catalyst, specifically, those containing
an element such as scandium (Sc), yttrium (Y), lanthanum (La) as
lanthanide element, cerium (Ce), praseodymium (Pr), neodymium (Nd),
samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb),
dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium
(Yb) and lutetium (Lu) are effective. In particular, those having
an alkylbenzenesulfonate, alkylsulfuric acid ester salt or triflate
structure are effective. Among these structures, a triflate
structure is preferred. As for the triflate, examples of the
structural formula include X(OSO.sub.2CF.sub.3).sub.3. X is a rare
earth element and preferably scandium (Sc), yttrium (Y), ytterbium
(Yb) or samarium (Sm).
[0056] The lanthanide triflate is described in detail, for example,
in Journal of Synthetic Organic Chemistry, Japan, Vol. 53, No. 5,
pp. 44-54.
[0057] The hydrolase-type catalyst is not particularly limited as
long as it catalyzes an ester synthesis reaction. Examples of the
hydrolase which can be used in the present invention include an
esterase classified into EC (enzyme code) group 3.1 (see, for
example, Maruo and Tamiya (supervisors), Koso Handbook (Handbook of
Enzyme), Asakura Shoten (1982)) such as carboxyesterase, lipase,
phospholipase, acetylesterase, pectinesterase, cholesterol
esterase, tannase, monoacylglycerol lipase, lactonase and
lipoprotein lipase; a hydrolase classified into EC group 3.2 having
activity on a glycosyl compound, such as glucosidase,
galactosidase, glucuronidase and xylosidase; a hydrolase classified
into EC group 3.3 such as epoxide hydrase; a hydrolase classified
into EC group 3.4 having activity on a peptide bond, such as
aminopeptidase, chymotrypsin, trypsin, plasmin and subtilisin; and
a hydrolase classified into EC group 3.7 such as phloretin
hydrase.
[0058] Among those esterases, an enzyme of hydrolyzing a glycerol
ester and isolating a fatty acid is called a lipase. The lipase is
advantageous in that, for example, this enzyme shows high stability
in an organic solvent, catalyzes an ester synthesis reaction with
good efficiency and is inexpensive. Accordingly, from the aspect of
yield and cost, a lipase is preferably used also in the production
process of a polyester of the present invention.
[0059] Lipases of various origins may be used but preferred
examples thereof include a lipase obtained from microorganisms of
Pseudomonas group, Alcaligenes group, Achromobacter group, Candida
group, Aspergillus group, Rizopus group and Mucor group, a lipase
obtained from plant seeds and a lipase obtained from animal
tissues, and further include pancreatin and steapsin. Among these,
preferred is a lipase originated in microorganisms of Pseudonionas
group, Candida group and Aspergillus group.
[0060] In order to achieve polycondensation at a lower temperature,
out of those catalysts, a surfactant-type catalyst, a rare earth
element catalyst and an enzyme catalyst are effective. As for the
rare earth metal catalyst, a catalyst comprising particularly Y,
Sc, Yb, Sm or the like as the constituent component is preferred.
It is important to select a polycondensation catalyst having higher
hydrophobicity or a larger molecular weight by keeping in mind that
the catalyst is dispensed to an emulsion or particle containing
polycondensable monomers undergoing polymerization and an aqueous
medium. A surfactant-type catalyst is preferably selected.
[0061] At this time, one catalyst or a plurality of catalysts can
be added in an amount of 0.1 to 100,000 ppm, preferably from 0.5 to
80,000 ppm, more preferably from 0.5 to 70,000 ppm, based on the
polycondensable monomers.
[0062] The polycondensation catalyst may be added either to an
aqueous phase or to an oil phase but is preferably added to an
aqueous phase. Particularly, in the miniemulsion polymerization
method, the catalyst is preferably added to an aqueous phase.
<Radical Polymerizable Monomer>
[0063] In the present invention, a radical polymerizable monomer
may be blended together with the polycondensable monomers and
radical-polymerized in a miniemulsion. This combination is
preferred in view of production of a toner resin as well as from
the standpoint of maintaining the properties of the toner resin. As
for the radical polymerizable monomer, one of the following
substances may be used alone or a plurality of these substances may
be used in combination, but the present invention is not limited to
those described below.
[0064] The radical polymerizable monomer which can be used in the
present invention is preferably, for example, a compound having an
ethylenically unsaturated bond, more preferably a vinyl-based
monomer or an olefin-based monomer.
[0065] Specific examples of the vinyl-based monomer include vinyl
aromatics such as styrene, .alpha.-methylstyrene,
.beta.-methylstyrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene,
p-tert-butylstyrene, p-n-hexylstyrene p-n-octylstyrene,
p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene,
p-methoxystyrene and p-phenylstyrene; unsaturated carboxylic acids
such as (meth)acrylic acid (the term "(meth)acryl" indicates acryl
and methacryl; hereinafter the same), crotonic acid, maleic acid,
fumaric acid, citraconic acid and itaconic acid; unsaturated
carboxylic acid esters such as methyl (meth)acrylate, ethyl
(meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl
(meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate,
glycidyl (meth)acrylate and benzyl (meth)acrylate; unsaturated
carboxylic acid derivatives such as (meth)acrylaldehyde,
(meth)acrylonitrile and (meth)acrylamide; N-vinyl compounds such as
N-vinylpyridine and N-vinylpyrrolidone; vinyl esters such as vinyl
formate, vinyl acetate and vinyl propionate; vinyl halide compounds
such as vinyl chloride, vinyl bromide and vinylidene chloride;
N-substituted unsaturated amides such as N-methylolacrylamide,
N-ethlolacrylamide, N-propanolacrylamide, N-methylolmaleinamic
acid, N-methylolmaleinamic acid ester, N-methylolmaleimide and
N-ethylolmaleimide; conjugated dienes such as butadiene and
isoprene; polyfunctional vinyl compounds such as divinylbenzene,
divinylnaphthalene and divinylcyclohexane; and polyfunctional
acrylates such as ethylene glycol di(meth)acrylate, diethylene
glycol di(meth)acrylate, propylene glycol di(meth)acrylate,
tetramethylene glycol di(meth)acrylate, neopentyl glycol
di(meth)acrylate, hexamethylene glycol di(meth)acrylate,
trimethylol propane di(meth)acrylate, trimethylol propane
tri(meth)acrylate, glycerol di(meth)acrylate, glycerol
tri(meth)acrylate, pentaerythritol di(meth)acrylate,
pentaerythritol tri(meth)acrylate, pentaerythritol
tetra(meth)acrylate, dipentaerythritol di(meth)acrylate,
dipentaerythritol tri(meth)acrylate, dipentaerythritol
tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate,
dipentaerythritol hexa(meth)acrylate, sorbitol tri(meth)acrylate,
sorbitol tetra(meth)acrylate, sorbitol penta(meth)acrylate and
sorbitol hexa(meth)acrylate, Among these, N-substituted unsaturated
amides, conjugated dienes, polyfunctional vinyl compounds and
polyfunctional acrylates can bring about a crosslinking reaction in
the produced polymer.
[0066] Examples of the olefin-based monomer include ethylene,
propylene, isobutylene, 1-butene, 1-pentene and 4-methyl-1-pentene.
Examples of the diolefin-based monomer include butadiene, isoprene
and chloroprene. Among the radical polymerizable monomers described
above, preferred as the resin are vinyl aromatics and carboxylic
acid esters.
[0067] The radical polymerizable monomer which can be used in the
present invention preferably contains a radical polymerizable
monomer having a hydrophilic group. The hydrophilic group includes,
for example, a polar group and examples thereof include, but are
not limited to, an acidic polar group such as carboxyl group,
sulfone group, a phosphoric acid group and a formyl group; a basic
polar group such as amino group, and a neutral polar group such as
amide group, hydroxyl group and cyano group. Among these, an acidic
polar group is preferably used in the toner. When a radical
polymerizable monomer having this polar group is present on the
resin particle surface in a certain specific range, this is
preferred because an aggregating property is imparted to the resin
particle to enable the production of a toner from the resin
particles and the toner can have a sufficiently high
electricity.
[0068] The acidic group is preferably a carboxyl group or a sulfone
group. Examples of the monomer having such an acidic group include
an .alpha.,.beta.-ethylenically unsaturated compound having a
carboxyl group, and an .alpha.,.beta.-ethylenically unsaturated
compound having a sulfone group. Examples of the
.alpha.,.beta.-ethylenically unsaturated compound having a carboxyl
group include an acrylic acid, a methacrylic acid, a fumaric acid,
a maleic acid, an itaconic acid, a cinnamic acid, a monomethyl
maleate, a monobutyl maleate and a monooctyl maleate, and examples
of the .alpha.,.beta.-ethylenically unsaturated compound having a
sulfone group include a sulfonated ethylene, an Na salt thereof, an
allylsulfosuccinic acid and an octyl allylsulfosuccinate. Among
these, an .alpha.,.beta.-ethylenically unsaturated compound having
a carboxyl group is preferred. One of these monomers may be used
alone or two or more thereof may be used in combination.
[0069] The radical polymerizable monomer used in combination is
preferably blended in an amount of 3 to 300 wt %, more preferably
from 5 to 200 wt %, based on the polycondensable monomers.
[0070] In the production of the resin particle for use in the
present invention, in addition to the polycondensable monomers and
the radical polymerizable monomer, another polymerizable monomer
which can be polymerized in an aqueous medium, may also be added
within the range of not impairing the properties necessary for the
use end such as resin particle liquid dispersion, toner or
image.
[0071] Furthermore, in the present invention, a co-surfactant is
preferably used in an amount of 0.1 to 40 wt % based on the
polycondensable monomers. The co-surfactant is added to reduce the
Ostwald ripening (Ostwald growth) in the so-called miniemulsion
polymerization. As for the co-surfactant, those generally known as
a co-surfactant in the miniemulsion process may be used. Examples
thereof include, but are not limited to, alkanes having a carbon
number of 8 to 30, such as dodecane, hexadecane and octadecane;
alkyl alcohols having a carbon number of 8 to 30, such as lauryl
alcohol, cetyl alcohol and stearyl alcohol; alkanethiols having a
carbon number of 8 to 30, such as dodecanethiol, lauryl mercaptan,
cetyl mercaptan and stearyl mercaptan; a polymer thereof with
acrylic acid esters or methacrylic acid esters; a polymer or
polyadducts, such as polystyrene and polyester; carboxylic acids;
ketones; and amines.
[0072] Among these co-surfactants, preferred are hexadecane, cetyl
alcohol, dodecanethiol, stearyl methacrylate, lauryl methacrylate,
polyester and polystyrene, and for the purpose of avoiding the
generation of a volatile organic substance, more preferred are
stearyl methacrylate, lauryl methacrylate, polyester and
polystyrene.
[0073] The polymer or polymer-containing composition usable for the
co-surfactant may contain, for example, a copolymer, block
copolymer or mixture with another monomer. Also, a plurality of
co-surfactants may be used in combination.
[0074] It is also important that the resin particle liquid
dispersion is free from generation of ultrafine powder or
ultra-coarse powder. In this light, the percentage of particles
having a median diameter of 0.01 .mu.m or less or a median diameter
of 5.0 .mu.m or more (hereinafter sometimes referred to as a
"large/small particle overall percentage") is preferably 10% or
less, more preferably 5% or less.
[0075] The median diameter of the resin particle can be measured,
for example, by a laser diffraction-type particle size distribution
measuring device (LA-920, manufactured by Horiba Ltd.).
[0076] In the polycondensable polymer produced in the present
invention, the weight average molecular weight of the
polycondensable polymer particle for toner is suitably from 1,500
to 60,000, preferably from 3,000 to 40,000. When the weight average
molecular weight is in this range, sufficiently high cohesive force
as the binder resin and good hot offset resistance are obtained and
the lowest fixing temperature is advantageously not elevated.
[0077] In the resin produced by using the above-described radical
polymerizable monomer, in view of fixing property and image forming
property, the glass transition temperature Tg as the resin for
toner is preferably from 40 to 100.degree. C. When the Tg is in
this range, the cohesive force of the binder resin itself is not
decreased in the high-temperature region and hot offset scarcely
occurs at the fixing. Also, the lowest fixing temperature is not
elevated and this is preferred. The glass transition temperature is
more preferably from 50 to 80.degree. C., and most preferably from
50 to 70.degree. C.
[0078] As for the polymerization method of the radical
polymerizable monomer, a known polymerization method such as a
method using a radical polymerization initiator, a
self-polymerization method under heat, and a method using
ultraviolet irradiation may be employed. In the method using a
radical initiator, the radical polymerization initiator may be
either an oil-soluble initiator or a water-soluble initiator.
[0079] Examples of the radical polymerization initiator include
ammonium persulfate, potassium persulfate, sodium persulfate,
2,2'-azobis(2-methylpropionamido)dihydrochloride,
tert-butylperoxy-2-ethylhexanoate, cumyl perpivalate,
tert-butylperoxylaurate, benzoyl peroxide, lauroyl peroxide,
octanoyl peroxide, di-tert-butyl peroxide, tert-butylcumyl
peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile,
2,2'-azobis(2-methylbutyronitrile),
2,2'-azobis(2,4-dimethylvaleronitrile),
2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile),
1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane,
1,1-bis(tert-butylperoxy)cyclohexane,
1,4-bis(tert-butylperoxycarbonyl)cyclohexane,
2,2-bis(tert-butylperoxy)octane, n-butyl-4,4-bis(tert-butylperoxy)
valylate, 2,2-bis(tert-butylperoxy)butane,
1,3-bis(tert-butylperoxyisopropyl)benzene,
2,5-dimethyl-2,5-di(tert-butylperoxy)hexane,
2,5-dimethyl-2,5-di(tert-butylperoxy)hexane,
2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di-tert-butyldiperoxy
isophthalate, 2,2-bis(4,4-di-tert-butylperoxycyclohexyl)propane,
di-tert-butylperoxy .alpha.-methylsuccinate, di-tert-butylperoxy
dimethylglutarate, di-tert-butylperoxy hexahydroterephthalate,
di-tert-butylperoxy azelate,
2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diethylene
glycol-bis(tert-butylperoxycarbonate), di-tert-butylperoxy
trimethyladipate, tris(tert-butylperoxy)triazine,
vinyltris(tert-butylperoxy)silane,
2,2'-azobis(2-methylpropionamidinedihydrochloride),
2,2'-azobis[N-(2-carboxyethyl)-2-methyl-propionamidine] and
4,4'-azobis(4-cyanovaleric acid).
[0080] In the case where the resin particle contains a radical
polymerizable polymer, the weight average molecular weight of the
radical polymerizable polymer is preferably from 5,000 to 200,000,
more preferably from 8,000 to 100,000.
[0081] In the present invention, the dispersion medium of the resin
particle liquid dispersion for an electrostatic image developing
toner is an aqueous medium.
[0082] Examples of the aqueous medium which can be used in the
present invention include water such as distilled water and ion
exchanged water, and alcohols such as ethanol and methanol. Among
these, ethanol and water are preferred, and water such as distilled
water and ion exchanged water is more preferred. One of these
aqueous mediums may be used alone or two or more thereof may be
used in combination.
[0083] Also, the aqueous medium may contain a water-miscible
organic solvent. Examples of the water-miscible organic solvent
include acetone and acetic acid.
[0084] In the resin particle liquid dispersion of the present
invention, the resin particle having a viscoelasticity, a melting
point and a particle diameter suitable for an electrostatic image
developing toner may also be produced by combining the following
techniques in a composite manner. For example, it is more preferred
to combine multiple factors such as introduction of a crosslinked
structure between the polycondensable monomer and another
polymerizable monomer, introduction of a urethane bond,
introduction of a carbodiimide group, control of the molecular
weight of the polycondensable polymer, introduction of an ionomer,
introduction of a graft bond, the compositional ratio between the
polycondensable polymer and another polymerizable polymer, and a
resin particle-cooling method.
[0085] In one appropriate method, an unsaturated bond-containing
monomer which is a polycondensable monomer capable of forming a
crosslinked structure with a radical polymerizable polymer is mixed
as a polycondensable monomer, and a crosslinked structure is
introduced between the polycondensable polymer and the radical
polymerizable polymer through a polycondensation reaction and a
radical polymerization reaction in an aqueous medium. In this case,
the unsaturated bond-containing monomer (crosslinking agent) is
preferably blended at a proportion of 20 to 50 wt % based on all
monomers. When the crosslinking agent content is 20 wt % or more,
the viscoelasticity does not decrease particularly at ordinary
temperature, and when it is 50 wt % or less, the number of
crosslinking points in the resin is not excessively large and this
is preferred because the properties of the crystalline resin can be
fully exerted. Incidentally, the term "all monomers" indicates all
monomers (for example, the polycondensable monomer, the radical
polymerizable monomer and the unsaturated bond-containing monomer)
constituting the resin particle.
[0086] The thus-formed resin particle where a polycondensable
polymer and a radical polymerizable polymer are crosslinked can
have low-temperature fixing property of the polycondensable
polymer, excellent offset resistance of the radical polymerizable
polymer, and strength at ordinary temperature.
[0087] The unsaturated bond-containing monomer (crosslinking agent)
is preferably, for example, an unsaturated bond-containing
carboxylic acid or an acid anhydride or lower ester thereof, more
preferably an unsaturated dicarboxylic acid or an acid anhydride or
lower ester thereof. Specific preferred examples of the unsaturated
dicarboxylic acid include, but are not limited to, a fumaric acid,
a maleic acid, a citraconic acid, an alkenylsuccinic acid, an
itaconic acid, a mesaconic acid, a dimethylmaleic acid and
dimethylfumaric acid. Among these, a maleic acid, a fumaric acid,
and a monoester thereof are preferred. Incidentally, the lower
ester means an ester with an aliphatic alcohol having a carbon
number of 1 to 8. Also, the monoester is, for example, a maleic
acid monoesterified with an aliphatic alcohol having a carbon
number of 1 to 8, and specific examples thereof include monomethyl
maleate, monoethyl maleate, monopropyl maleate, monobutyl maleate,
monopentyl maleate and monohexyl maleate.
[0088] The crosslinking method, the crosslinking agent and the
polymer component used for the crosslinking with the
polycondensable polymer are not particularly limited and are
appropriately selected.
[0089] In order to cause the resin particle liquid dispersion of
the present invention to achieve desired properties by the
molecular weight of the polycondensable polymer, the resin particle
for use in the present invention has a number average molecular
weight Mn of 2,000 to 20,000 and a weight average molecular weight
Mw of 4,000 to 100,000, preferably Mn of 2,500 to 10,000 and Mn of
4,500 to 50,000, more preferably Mn of 3,000 to 10,000 and Mw of
5,000 to 40,000. The polycondensable polymer having a molecular
weight in this range can be obtained by introducing a urethane bond
or a carbodiimide group to extend the molecular chain or by
accelerating the reaction with use of another chain extending
agent, a dehydrating agent or the like.
[0090] With respect to the introduction of a urethane bond,
examples of the resin include an addition reaction product of
polyol and isocyanate, a reaction product of polyester having a
hydroxyl group and polyisocyanate, and a reaction product of
polyester, polyisocyanate and polyol. The polyester having a
hydroxyl group is preferably, for example, a polycondensate of
polycarboxylic acid and polyol, which is excessive in the hydroxyl
group equivalent number. The polyisocyanate as used herein means a
compound having a plurality of isocyanate groups, and a
polyisocyanate having 1.5 or more isocyanate groups on average
within one molecule is preferably contained at a proportion of 20.0
to 90.0 wt % based on all monomers. When the percentage of this
polyisocyanate is 20.0 wt % or more, the effect of extending the
chain in an aqueous medium is sufficiently high and a necessary
viscoelasticity is obtained, and when the percentage is 90.0 wt %
or less, the oil droplet is prevented from excessive elevation of
the hydrophilicity and can easily maintain the stability and this
is preferred. The percentage of this polyisocyanate is more
preferably from 20.0 to 50.0 wt %.
[0091] Examples of the polyisocyanate include an aliphatic
polyisocyanate (e.g., tetramethylene diisocyanate, hexamethylene
diisocyanate, 2,6-diisocyanatomethyl caproate); an alicyclic
polyisocyanate (e.g., isophorone diisocyanate, cyclohexylmethane
diisocyanate); an aromatic polyisocyanate (e.g., tolylene
diisocyanate, diphenylmethane diisocyanate); an aromatic aliphatic
polyisocyanate (e.g., .alpha.,.alpha.',.alpha.'-tetramethylxylylene
diisocyanate); isocyanurates; a polyisocyanate obtained by blocking
the above-described polyisocyanate with a phenol derivative, oxime,
caprolactam or the like; and a combination of two or more of these
polyisocyanates.
[0092] As for the dehydrating agent for use in the present
invention, a generally usable dehydrating agent or water-absorbing
agent is used to coexist at the polycondensation reaction in water,
whereby the polymerization reaction can be accelerated.
[0093] With respect to the introduction of a carbodiimide group,
the carbodiimide group is characterized in that a carbamoylamide
bond or an isourea bond is formed by the reaction with a carboxyl
group or a hydroxyl group in a polyester resin or the like and
moreover, the reaction proceeds even in the presence of water.
Therefore, the effect of increasing the molecular weight by
grafting or crosslinking of the polycondensation resin such as
polyester is high and the mechanical strength as a toner can be
enhanced. The carbodiimide compound for use in the present
invention has a carbodiimide group within the molecule and forms a
carbamoylamide bond by the reaction with a carboxyl group of a
polyester resin or forms a isourea bond by the reaction with a
hydroxyl group of a polyester resin. Examples of the
polycarbodiimide resin obtained from these raw materials include
poly(tert-butylcarbodiimide), polytetramethylxylylene carbodiimide,
poly(2,4-toluylenecarbodiimide), poly(2,6-toluylenecarbodiimide),
poly(o-toldinecarbodiimide),
poly(4,4'-diphenylmethanecarbodiimide),
poly(4,4'-dicyclohexylmethanecarbodiimide),
poly(4,4'-diphenylethercarbodiimide),
poly(3,3'-dimethoxy-4,4'-diphenylcarbodiimide),
poly(p-phenylenecarbodiimide), poly(naphthylene-1,5-carbodiimide),
poly(m-xylylenecarbodiimide), poly-hydrogenated xylylene
carbodiimide, polyhexamethylene carbodiimide,
poly-trimethylhexamethylene carbodiimide and polyisophorone
carbodiimide.
[0094] As for the generally available commercial product,
Carbodilite E Series (emulsion type), V Series (aqueous type) or
the like, produced by Nisshinbo Industries, Inc., are usable.
[0095] With respect to the introduction of an ionomer into the
polycondensable polymer, this can be realized by neutralizing a
part, preferably from 20 to 80%, of the carboxyl group contained in
the polycondensable polymer with a metal salt containing, for
example, zinc, cobalt, nickel, aluminum or copper(II). Examples of
the polyvalent metal compound suitably used at the formation of an
ion crosslinked structure by the coordination bonding (ionic
bonding) with the above-described carboxyl group include an acetate
and an oxide of alkaline earth metal or zinc group metal.
Furthermore, as for the method of introducing an ionomer resin into
the toner in the production process of a toner of the present
invention, which is described later, a method of incorporating an
ionomer resin into the toner by performing aggregation after adding
an ionomer resin liquid dispersion in the aggregation step may be
used. The metal salt of the polyester-containing polymer obtained
by the polycondensation in an aqueous medium may be formed, for
example, by dissolving the polymer in an organic solvent, adding a
metal compound, and stirring and mixing the solution, if desired,
under heating and in this case, a uniform ionomer resin can be
obtained. Also, an ionomer may be incorporated into the toner by
adding, in the aggregation step, a resin particle liquid dispersion
having dispersed therein a resin prepared by melt-mixing a
polyester resin and an ionomer resin.
[0096] In addition, for example, a combination use of a crystalline
polycondensable polymer and a non-crystalline radical polymerizable
polymer, or a combination use of a crystalline polycondensable
polymer and a non-crystalline polycondensable polymer may be
preferably employed.
[0097] In the case of using a crystalline polycondensable polymer
and a non-crystalline radical polymerizable polymer in combination,
the compositional ratio is preferably from 4:6 to 0.5:9.5, more
preferably from 4.5:5.5 to 1.0:9.0, in terms of the weight ratio
between the crystalline polycondensable polymer and the
non-crystalline radical polymerizable polymer.
[0098] In the case of using a crystalline polycondensable polymer
and a non-crystalline polycondensable polymer in combination,
examples of the method therefor include a method of mixing these
polycondensable polymers, forming particles therefrom, and
producing a liquid dispersion, and a method of causing one
polycondensable polymer to coexist when another polycondensable
polymer is polycondensed in an aqueous medium. The mixing ratio can
be appropriately selected according to the kind of the
monomers.
[0099] When the above-described method is used alone, this provides
effects such as three-dimensional configuration of polymer,
increase of molecular weight, introduction of metal ion, control of
crystallinity and balancing between crystalline polymer and
non-crystalline polymer. However, when this method is combined with
an appropriate technique, a resin having low-temperature fixing
property, sharp-melt property and offset resistance can be produced
in an aqueous medium.
[0100] The resin particle for use in the present invention
preferably has an acid value of 1 to 50 mgKOH/g. A first reason
therefor is because the control of particle diameter and particle
diameter distribution of a toner in an aqueous medium is
indispensable for use in practice as a toner assured of high image
quality and when the acid value is 1 mgKOH/g or more, a
satisfactory particle diameter and a satisfactory particle diameter
distribution are achieved and also in view of electricity of the
toner, a sufficiently high electricity can be obtained.
Furthermore, when the acid value is 50 mgKOH/g or less, a molecular
weight sufficiently large to ensure an image quality strength as a
toner at the polycondensation can be obtained and also, excellent
image reliability with less environmental dependency of the
electricity of toner at a high humidity is advantageously
obtained.
(Production Process of Resin Particle Liquid Dispersion for
Electrostatic Image Developing Toner)
[0101] The production process of a resin particle liquid dispersion
for an electrostatic image developing toner of the present
invention comprises a step of preparing an emulsified liquid
dispersion comprising an aqueous medium having emulsion-dispersed
therein an oil phase containing at least polycondensable monomers
(hereinafter sometimes referred to as an "emulsion-dispersion
step"), and a step of polycondensing the polycondensable monomers
(hereinafter sometimes referred to as a "polycondensation
step").
[0102] The production process of a resin particle liquid dispersion
is described below.
[0103] The production process of a resin particle liquid dispersion
of the present invention comprises a step of preparing an
emulsified liquid dispersion comprising an aqueous medium having
emulsion-dispersed therein an oil phase containing at least
polycondensable monomers.
[0104] Here, for forming a particle emulsion, for example, a
monomer solution (oil phase) having added thereto a co-surfactant
and an aqueous surfactant solution (aqueous phase) are uniformly
mixed and emulsified in a shear mixing apparatus such as piston
homogenizer, microfluidizing device (for example, "Microfluidizer"
manufactured by Microfluidics) and ultrasonic disperser. At this
time, the amount of the oil phase charged into the aqueous phase is
preferably on the order of 0.1 to 50 wt % based on the total amount
of the aqueous phase and the oil phase. The amount of the
surfactant used is preferably less than the critical micelle
concentration (CMC) in the presence of the emulsion formed. Also,
the amount of the co-surfactant used is preferably from 0.1 to 40
parts by weight, more preferably from 0.1 to 20 parts by weight,
per 100 parts by weight of the oil phase.
[0105] Incidentally, a "miniemulsion polymerization method" which
is a method of polymerizing monomers by using a surfactant in an
amount less than the critical micelle concentration (CMC) and a
co-surfactant in combination in the presence of a polymerization
initiator for the monomer emulsion is preferred, because, as
described above, monomers are polymerized in a monomer particle
(oil droplet) and therefore, uniform polymer particles are formed.
Furthermore, the "miniemulsion polymerization method" is
advantageous in that since diffusion of the monomer is not required
in the polymerization process, the polymer can be present as it is
in the polymer particle.
[0106] Also, so-called "microemulsion polymerization" of producing
particles having a particle diameter of 5 to 50 nm described, for
example, in J. S. Guo, M. S. El-Aasser, and J. W. Vanderhoff, J.
Appl. Polym. Sci.: Polym. Chem. Ed., Vol. 27, page 691 (1989) has a
dispersion structure and a polymerization mechanism similar to the
"miniemulsion polymerization" as referred to in the present
invention and can be used also in the present invention. In the
"microemulsion polymerization", a surfactant higher than the
critical micelle concentration (CMC) is used in a large amount and
there may arise a problem, for example, a large amount of a
surfactant is mixed in the obtained polymer particle or a huge time
is necessary for the step of removing the surfactant, such as water
washing, acid washing or alkali washing.
[0107] The production process of a resin particle liquid dispersion
of the present invention comprises a step of polycondensing the
polycondensable monomers in an aqueous medium.
[0108] In the present invention, monomers are previously dispersed
in an aqueous medium where if desired, a surfactant, a
co-surfactant and the like are dissolved in a small amount, by
using mechanical shear force, ultrasonic wave or the like, and the
dispersion is then heated to effect polycondensation.
Alternatively, monomers are dissolved in another medium to prepare
an oil phase where if desired, a surfactant, a co-surfactant and
the like are further dissolved, the oil phase is dispersed in the
above-described aqueous medium, and the dispersion is then heated
to effect polycondensation. As for the polymerization method in
this case, an ordinary heterogeneous polymerization mode in an
aqueous medium, such as suspension-polymerization method,
miniemulsion method, microemulsion method, multi-step swelling
method, emulsion-polymerization method containing seed
polymerization, and extension reaction method using a resin (e.g.,
urethane), may be utilized as the polymerization method of
particles in an aqueous medium. Among these polymerization methods,
from the standpoint that a uniform particle diameter and a
regulated particle diameter distribution are readily obtained, a
microemulsion method and a miniemulsion polymerization method are
preferred, and a miniemulsion polymerization method is most
preferred.
[0109] The polycondensation reaction in an aqueous medium depends
on the stability and viscosity of the oil droplet formed in the
aqueous medium and since the polycondensation takes place on the
oil droplet surface, this reaction is established on the basis of
balance among the polycondensation reaction on the oil droplet
surface, the drag-in of reactant into the oil droplet, and the
bleed-out of unreacted material to the oil droplet surface. If this
balance is lost, the stability of oil droplet or the progress of
polycondensation may be inhibited.
[0110] The resin particles dispersed in the resin particle liquid
dispersion are preferably polycondensed in an aqueous medium at a
polycondensation temperature Tc in the range of (Tm-20.degree.
C.)<Tc<(Tm+20.degree. C.) wherein Tm is the melting point of
the resin particle. The polycondensation temperature is preferably
higher than (Tm-20.degree. C.), because the viscosity of the
polymer produced is not excessively elevated and this allows for
easy movement of the polymer produced on the surface of an oil
droplet dispersed in an aqueous medium, as a result, an unreacted
monomer is present on the oil droplet surface with high probability
and the polycondensation can satisfactorily proceed. On the other
hand, the reaction temperature is preferably lower than
(Tm+20.degree. C.), because the viscosity of the polycondensable
polymer does not excessively decrease and this ensures good
stability of the oil droplet as well as less occurrence of the
drag-in of an insufficiently polycondensed polycondensable polymer
into the oil droplet.
[0111] In the polycondensation step of the present invention,
assuming that the highest temperature out of melting points of the
polycondensable monomers forming a polycondensation resin is Th,
the polycondensation is preferably performed at a polycondensation
temperature Tc of 45.degree. C.<Tc<Th in an aqueous medium.
The polycondensation temperature preferably exceeds 45.degree. C.,
because the catalyst exhibits good activity and the
polycondensation satisfactorily proceeds. On the other hand, the
polycondensation temperature is preferably less than Th, because
the polycondensable monomer is not entirely melted and the oil
droplet is assured of good stability with less occurrence of the
positional exchange between a polymer and a monomer before
polycondensation satisfactorily proceeds.
[0112] The production process of a resin particle liquid dispersion
of the present invention may comprise a step of rapidly cooling the
resin particle liquid dispersion to a temperature of -10.degree. C.
or more and Tc-60.degree. C. or less (hereinafter sometimes
referred to as a "cooling step") after the polycondensation step.
In the case where a polymerization step described later is
performed after the polycondensation step, the cooling step is
preferably performed after the polymerization step.
[0113] As for the cooling method, a method of rapidly cooling the
resin particle liquid dispersion to a temperature of -10.degree. C.
or more and Tc-60.degree. C. or less after a miniemulsion
polymerization reaction including polycondensation is preferred. By
rapidly cooling the resin particle liquid dispersion produced at
the above-described polycondensation temperature or the resin
particle liquid dispersion produced by subsequently passing through
other reactions such as radical polymerization, the composition in
the resin particle can be uniformly dispersed and fixed and
furthermore, aggregation of particles with each other can be
suppressed, as a result, a resin particle liquid dispersion with
high quality and good liquid dispersion stability can be obtained.
The cooling rate is not particularly limited but is preferably
2.degree. C./min or more, more preferably from 3 to 20.degree.
C./min. When the cooling rate is in this range, the particle
diameter of the resin particle is not increased and the liquid
dispersion is advantageously assured of good stability. The cooling
may be performed, for example, by a method using a cooling medium
such as ice or a method using cold blast or the like, or by using a
heat exchanger or the like.
[0114] The production process of a resin particle liquid dispersion
of the present invention may comprise a step of polymerizing a
radical polymerizable monomer (hereinafter sometimes referred to as
a "radical polymerization step" or simply a "polymerization
step").
[0115] In the polymerization step of the present invention,
similarly to the polycondensation step, a plurality of
polymerizations may be performed simultaneously or successively.
For example, a radical polymerizable monomer as a monomer component
of undergoing the polymerization is mixed together with the
polycondensation monomers, and the radical polymerization may be
performed simultaneously with the polycondensation reaction or
after the polycondensation, or inversely, the polycondensation may
be performed after the radical polymerization. At this time, a
polycondensation catalyst may be mixed in the monomer component. As
for the radical polymerization catalyst, a radical initiator may be
added to the monomer mixture or aqueous medium before, during or
after the polycondensation.
[0116] Also, a chain transfer agent may be used at the radical
polymerization. The chain transfer agent is not particularly
limited but a compound having a thiol component may be used.
Specifically, alkanethiols such as hexanethiol, heptanethiol,
octanethiol, nonanethiol, decanethiol and dodecanethiol are
preferred. Use of a chain transfer agent is advantageous
particularly in that the molecular weight distribution can be made
narrow and therefore, the toner can have good storability at high
temperatures.
[0117] At the polymerization in an aqueous medium of the present
invention, the monomer components before polycondensation may be
previously mixed with a colorant, a fixing aid such as wax, and
other components generally required in the polymerization reaction
as well as in the production of toner, such as electrification aid,
dehydrating agent, water-absorbing agent and chain extending
agent.
[0118] In the present invention, the polymerization step and/or the
polycondensation step may contain a polymerization reaction of the
above-described monomers with a prepolymer which has been
previously prepared. The prepolymer is not limited as long as it is
a polymer capable of being dissolved or uniformly mixed in the
monomers, and may further contain, for example, a homopolymer of
the above-described monomer, a copolymer comprising a combination
of two or more monomers containing the above-described monomer, or
a mixture or graft polymer thereof.
[0119] In the present invention, in the case of polymerizing
polycondensable monomers and a radical polymerizable monomer, the
radical polymerizable monomer may be previously mixed with the
polycondensation monomers at the step of polymerization or
polycondensation in an aqueous medium, so that a hybrid particle
comprising a polymer of those monomers can be finally obtained
through polycondensation and radical polymerization.
[0120] Furthermore, in the polycondensation step, it is also
possible to previously form a polymer having a low molecular weight
by a block polymerization method or a solution polymerization
method, emulsify or disperse the polymer in an aqueous medium and
perform a polycondensation reaction to reach the final molecular
weight. Also in this case, the emulsion-dispersion may be performed
after the radical polymerizable monomer is mixed with a low
molecular weight polyester or with a low molecular weight polyester
and polycondensable polymers. In the polycondensation in an aqueous
medium of the present invention, the acid value of the polymerized
polymer affects the final molecular weight or the polymerization
speed and therefore, it is preferred in view of production to use a
method of causing, for example, a radical polymerizable vinyl
monomer having low solubility in water to coexist during
polycondensation, a method of previously adjusting the acid value
of a polyester monomer to a lower state by preparing a low
molecular weight form (or a medium molecular weight form) in the
level of not causing a problem in the emulsion-dispersion, and then
obtaining a final high molecular form in an aqueous medium, or a
combination of these two methods, that is, a method of performing
both preliminary polymerizations of a radical polymerizable monomer
and a polyester.
(Production Process of Electrostatic Image Developing Toner)
[0121] The production process of an electrostatic image developing
toner (hereinafter sometimes simply referred to as a "toner") of
the present invention is a method for producing an electrostatic
image developing toner, comprising a step (hereinafter sometimes
referred to as an "aggregation step") of aggregating resin
particles in a liquid dispersion containing at least a resin
particle liquid dispersion to obtain aggregate particles, and a
step (hereinafter sometimes referred to as a "coalescence step") of
heating and thereby coalescing the aggregate particles, wherein the
resin particle liquid dispersion is the resin particle liquid
dispersion of the present invention.
[0122] In the production process of an electrostatic image
developing toner of the present invention, if desired, a colorant
particle-containing particle (in the case where a colorant is
previously added to the resin at the polycondensation step or the
like, the resin itself is a colored particle), a releasing agent
particle, another resin particle, a liquid dispersion thereof or
the like may be added to the liquid dispersion containing at least
the resin particle liquid dispersion of the present invention. In
the production process of an electrostatic image developing toner
of the present invention, the particle diameter and particle
diameter dispersion of the toner can be adjusted by aggregating
(associating) the resin particles and other added particles in the
liquid dispersion according to a known aggregation method of
aggregating (associating) these particles. Regulation of toner
particles by an emulsion polymerization-aggregation method is
suitably used. More specifically, the resin particle liquid
dispersion of the present invention is mixed with a colorant
particle liquid dispersion, a releasing agent particle liquid
dispersion and the like, a coagulant is added to generate
hetero-aggregation and thereby form an aggregate particle having a
toner size, and the aggregate particles are fused and coalesced
under heating to a temperature higher than the glass transition
point or melting point of the resin particle, then washed and
dried. In this production process, the toner shape from amorphous
to spherical can be controlled by selecting the heating temperature
condition.
[0123] In the aggregation step of the present invention,
aggregation and subsequent procedure may also be performed after a
resin particle liquid dispersion other than the resin particle
liquid dispersion of the present invention is mixed with the resin
particle liquid dispersion of the present invention. At this time,
a particle having a multilayer structure may be produced, for
example, by previously aggregating the resin particle liquid
dispersion of the present invention to form a first aggregate
particle, and then further adding the resin particle liquid
dispersion of the present invention or another resin particle
liquid dispersion to form a second shell layer on the first
particle surface. Needless to say, a multilayer particle may also
be produced by the additions in the reverse order from the
above-described example.
[0124] As for the coagulant, a surfactant, an inorganic salt or a
divalent or higher polyvalent metal salt may be suitably used. In
particular, a metal salt is preferred in view of aggregation
control and properties such as toner chargeability. The metal salt
compound used for the aggregation is obtained by dissolving a
general inorganic metal compound or a polymer thereof in the resin
particle liquid dispersion, and the metal element constituting the
inorganic metal salt may be sufficient if it is a metal element
having a divalent or higher electric charge, which belongs to
Groups 2A, 3A, 4A, 5A, 6A, 7A, 8, 1B, 2B and 3B of the Periodic
Table (long Periodic Table) and which dissolves in the form of ion
in an aggregation system of resin particles. Specific preferred
examples of the inorganic metal salt include a metal salt such as
calcium chloride, calcium nitrate, barium chloride, magnesium
chloride, zinc chloride, aluminum chloride and aluminum sulfate,
and an inorganic metal salt polymer such as polyaluminum chloride,
polyaluminum hydroxide and polycalcium sulfide. Among these, an
aluminum salt and a polymer thereof are preferred. Generally, in
order to obtain a sharper particle size distribution, the valence
number of the inorganic metal salt is preferably divalence rather
than monovalence and preferably trivalence or higher valence rather
than divalence. When the valence is the same, a polymerization-type
inorganic metal salt polymer is more preferred.
[0125] In the present invention, if desired, one or a plurality in
combination of known additives may be blended within the range of
not affecting the effects of the present invention. Examples of the
additive include a flame retardant, a flame retardant aid, a
brightener, a waterproof agent, a water repellent, an inorganic
filler (surface modifier), a releasing agent, an antioxidant, a
plasticizer, a surfactant, a dispersant, a lubricant, a filler, an
extender pigment, a binder and a charge-control agent. These
additives may be blended at any stage in the production of a
coating agent.
[0126] Out of the internal additives, as for the charge control
agent, various charge control agents commonly used, such as
quaternary ammonium salt compound and nigrosine-based compound, may
be used but in view of stability at the production and less
contamination by waste water, a material hardly soluble in water is
preferred.
[0127] Examples of the releasing agent which can be used include
low molecular weight polyolefins such as polyethylene,
polypropylene and polybutene; silicones showing a softening point
softening under heat; fatty acid amides such as oleic acid amide,
erucic acid amide, ricinoleic acid amide and stearic acid amide; an
ester wax; a vegetable wax such as carnauba wax, rice wax,
candelilla wax, Japan wax and jojoba oil; an animal wax such as
bees wax; a mineral or petroleum wax such as montan wax, ozokerite,
ceresin, paraffin wax, microcrystalline wax, microcrystalline wax
and Fischer-Tropsch wax; and a modified product thereof.
[0128] Such a wax is dispersed in an aqueous medium together with
an ionic surfactant and a polymer electrolyte such as polymer acid
or polymer base, and pulverized under heating to a temperature
higher than the melting point in a homogenizer or pressure jet-type
disperser capable of applying strong shear, whereby a liquid
dispersion of particles of 1 .mu.m or less can be produced.
[0129] Examples of the flame retardant and flame retardant aid
include, but are not limited to, a bromine-based flame retardant
already used in general, antimony trioxide, magnesium hydroxide,
aluminum hydroxide and ammonium polyphosphate.
[0130] Examples of the coloring component include a carbon black
such as furnace black, channel black, acetylene black and thermal
black; an inorganic pigment such as red iron oxide, iron blue and
titanium oxide; an azo pigment such as Fast Yellow, Disazo Yellow,
pyrazolone red, chelate red, Brilliant Carmine and Para Brown; a
phthalocyanine pigment such as copper phthalocyanine and nonmetal
phthalocyanine; a condensation polycyclic pigment such as
flavanthrone yellow, dibromoanthrone orange, perylene red,
Quinacridone Red and Dioxazine Violet; and various pigments such as
chrome yellow, Hansa Yellow, Benzidine Yellow, Indanthrene Yellow,
Quinoline Yellow, Permanent orange GTR, Pyrazolone Orange, Vulcan
Orange, Watchung Red, Permanent Red, DuPont Oil Red, Lithol Red,
Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue,
Ultramarine Blue, Carco Oil Blue, Methylene Blue Chloride,
Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate,
C.I. Pigment.cndot.Red 48:1, C.I. Pigment.cndot.Red 122, C.I.
Pigment.cndot.Red 57:1, C.I. Pigment.cndot.Yellow 12, C.I.
Pigment.cndot.Yellow 97, C.I. Pigment.cndot.Yellow 17, C.I.
Pigment.cndot.Blue 15:1 and C.I. Pigment.cndot.Blue 15:3. One of
these pigments may be used or two or more thereof may be used in
combination.
[0131] Similarly to the normal toner, an inorganic particle such as
silica, alumina, titania and calcium carbonate, or a resin particle
such as polyester and silicone, may be added in the dry state under
shearing to the surface of the toner after drying and used as a
flowability aid or a cleaning aid.
[0132] Examples of the surfactant which can be used in the present
invention include an anionic surfactant such as sulfuric ester salt
type, sulfonate type, phosphoric ester type and soap type; and a
cationic surfactant such as amine salt type and quaternary ammonium
salt type. It is also effective to use a nonionic surfactant in
combination, such as polyethylene glycol type, alkylphenol ethylene
oxide adduct type and polyhydric alcohol type. As for the
dispersing means, a generally employed device such as rotation
shearing homogenizer and media-containing ball mill, sand mill or
dynomill, may be used.
[0133] The toner of the present invention preferably has an
accumulated volume average particle diameter D.sub.50 of 3.0 to
20:0 .mu.m and a volume average particle size distribution index
GSDv of 1.4 or less, more preferably D.sub.50 of 3.0 to 9.0 .mu.m
and GSDv of 1.3 or less. When a cumulative distribution of each
volume is drawn from the small diameter side with respect to the
particle size range (channel) divided on the basis of particle size
distribution, the particle diameter at 16% accumulation is defined
as D.sub.16v and the particle diameter at 84% accumulation is
defined as D.sub.84v. Using these, the volume average particle size
distribution index (GSDv) is calculated according to the following
formula: GSDv=(D.sub.84V/D.sub.16V).sup.1/2
[0134] When the GSDv is 1.4 or less, uniform particle diameter and
good fixing property are attained and the apparatus is
advantageously free from a trouble ascribable to fixing failure.
Also, scattering of the toner causing contamination in the
apparatus or deterioration of the developer less occurs and this is
preferred. D.sub.50 in the above-described range is preferred
because appropriate adhesive force, good developability and
excellent image resolution are obtained.
[0135] The accumulated volume average particle diameter (D.sub.50)
and the volume average particle size distribution index GSDv can be
measured, for example, by a laser diffraction-type particle size
distribution measuring device.
[0136] In view of image forming property, the shape factor SF1 of
the toner of the present invention is preferably from 100 to 140,
more preferably from 110 to 135. The SF1 is calculated as follows.
SF .times. .times. 1 = ( ML ) 2 A .times. .pi. 4 .times. 100
##EQU1## wherein ML represents an absolute maximum length of the
particle and A represents a projected area of the particle.
[0137] These are quantified mainly by inputting a microscopic image
or a scanning electron microscopic image into a Luzex image
analyzer, and analyzing the image.
[0138] After drying the obtained toner, similarly to the normal
toner, for the purpose of imparting flowability or enhancing the
cleaning property, an inorganic particle such as silica, alumina,
titania, metatitanic acid compound and calcium carbonate, or a
resin particle such as vinyl-based resin, polyester and silicone,
may be used as an external additive and added to the toner particle
surface while applying shear in a dry state.
[0139] In the case of attaching such a particle to the toner
surface in an aqueous medium, as for the inorganic particle, those
usually used as an external additive to the toner surface, such as
silica, alumina, titania, calcium carbonate, magnesium carbonate
and tricalcium phosphate, all may be used by dispersing the
additive with an ionic surfactant, a polymer acid or a polymer
base.
(Electrostatic Image Developer)
[0140] The electrostatic image developing toner of the present
invention may be used as an electrostatic image developer. This
developer is not particularly limited as long as it contains the
electrostatic image developing toner, and may take an appropriate
component composition according to the purpose. When the
electrostatic image developing toner is used alone, the developer
is prepared as a one-component system electrostatic image
developer, whereas when the toner is used in combination with a
carrier, the developer is prepared as a two-component system
electrostatic image developer.
[0141] In the case of a one-component system developer, a method of
causing frictional electrification with a developing sleeve or an
electrifying member to form an electrified toner, and performing
development according to the electrostatic latent image may also be
applied.
[0142] The carrier is not particularly limited, but examples of the
carrier usually employed include a magnetic particle such as iron
powder, ferrite, iron oxide powder and nickel; a resin-coated
carrier obtained by coating the surface of a magnetic particle as a
core material with a resin such as styrene-based resin, vinyl-based
resin, ethyl-based resin, rosin-based resin, polyester-based resin
and methyl-based resin or with a wax such as stearic acid to form a
resin coat layer; and a magnetic material dispersion-type carrier
obtained by dispersing magnetic particles in a binder resin. Among
these, a resin-coated carrier is preferred because the toner
chargeability or the resistance of the entire carrier can be
controlled by the constitution of the resin coat layer.
[0143] The mixing ratio between the toner of the present invention
and the carrier in the two-component system electrostatic image
developer is usually from 2 to 10 parts by weight of toner per 100
parts by weight of carrier. The preparation method of the developer
is not particularly limited, but examples thereof include a method
of mixing the toner and the carrier by a V blender or the like.
(Image Forming Method)
[0144] The electrostatic image developing toner and electrostatic
image developer of the present invention may be used for an image
forming method in a normal electrostatic image developing system
(electrophotographic system).
[0145] The image forming method of the present invention is an
image forming method comprising a latent image-forming step of
forming an electrostatic latent image on the surface of a latent
image-holding member, a development step of developing the
electrostatic latent image formed on the surface of the latent
image-holding member with a developer containing a toner to form a
toner image, a transfer step of transferring the toner image formed
on the surface of the latent image-holding member to the surface of
a transferee member, and a fixing step of heat-fixing the toner
image transferred to the surface of the transferee member, wherein
the toner is the electrostatic image developing toner of the
present invention, or the developer is the electrostatic image
developer of the present invention.
[0146] The above-described steps all may utilize the steps known in
the image forming method, for example, the steps described in
JP-A-56-40868 and JP-A-49-91231. Also, the image forming method of
the present invention may comprise a step other than those steps,
and preferred examples of such a step include a cleaning step of
removing the electrostatic image developer remaining on the
electrostatic latent image-supporting member. In a preferred
embodiment, the image forming method of the present invention
further comprises a recycling step. This recycling step is a step
of transferring the electrostatic image developing toner recovered
in the cleaning step to the developer layer. The image forming
method in this embodiment comprising a recycling step can be
performed by using an image forming apparatus such as toner
recycling system-type copying machine or facsimile machine. The
image forming method of the present invention may also be applied
to a recycling system in which the cleaning step is omitted and the
toner is recovered simultaneously with the development.
[0147] As for the latent image-holding member, for example, an
electrophotographic photoreceptor or a dielectric recording
material may be used.
[0148] In the case of an electrophotographic photoreceptor, the
surface of the electrophotographic photoreceptor is uniformly
charged by a corotron charging device or a contact charging device
and then exposed to form an electrostatic latent image (latent
image-forming step). Thereafter, the photoreceptor is caused to
come in contact with or close to a developing roller having formed
on the surface thereof a developer layer to allow for attachment of
toner particles to the electrostatic latent image, thereby forming
a toner image on the electrophotographic photoreceptor (development
step). The toner image formed is transferred to the surface of a
transferee member such as paper by using a corotron charging device
(transfer step). Furthermore, the toner image transferred to the
surface of the transferee member is heat-fixed by a fixing machine
to form a final toner image (fixing step).
[0149] At the heat-fixing by a fixing machine, a releasing agent is
generally supplied to the fixing member of the fixing machine so as
to prevent offset or the like.
EXAMPLES
[0150] The present invention is described in greater detail below
by referring to Examples, but the present invention is not limited
thereto.
Example 1
[0151] TABLE-US-00001 <Preparation of Oil Phase 1>
1,9-Nonanediol (monomer melting point: 47.degree. C.) 11.3 parts by
weight 1,10-Decanedicarboxylic acid (dodecane diacid, 3.4 parts by
weight monomer melting point: 130.degree. C.) Diethyl fumarate
(monomer melting point: 2.degree. C.) 12.0 parts by weight (25 wt %
of the total) Styrene 21.0 parts by weight Stearyl methacrylate
1.66 parts by weight Dodecanethiol 1.0 part by weight
[0152] These components are dissolved under heat at 130.degree. C.
to prepare a uniform oil phase. TABLE-US-00002 <Preparation of
Aqueous Phase 1> Dodecylbenzenesulfonic acid 1.66 parts by
weight Water 200 parts by weight
<Production of Resin Particle Liquid Dispersion 1>
[0153] The aqueous solution above is prepared and stirred in a
constant-temperature bath at 70.degree. C. for 1 hour. The aqueous
phase is charged into a 1 liter-volume vessel and mixed with the
oil phase and after stirring in Ultra-Turrax (manufactured by IKA
Works, Inc.) at 8,000 rpm for 3 minutes, the resulting emulsified
product is charged into a 500 ml-volume reactor equipped with a
stirrer and subjected to polycondensation at 70.degree. C. for 24
hours in a nitrogen atmosphere.
[0154] Thereafter, a material obtained by dissolving 1.1 parts by
weight of ammonium persulfate in 10 parts by weight of ion
exchanged water is added to the resin particle liquid dispersion
prepared above, and polymerization is further performed for 6 hours
in a nitrogen atmosphere. The obtained liquid dispersion is rapidly
cooled with ice water, as a result, the liquid dispersion
temperature became 2.5.degree. C. This liquid dispersion is sampled
in a small amount and the physical properties of the
polyester/polystyrene composite polymer are measured.
[0155] Weight average molecular weight of polystyrene by GPC:
48,200
[0156] Number average molecular weight of polyester by GPC:
2,250
[0157] Melting point of polyester: 59.degree. C.
[0158] Median diameter: 0.4 .mu.m
[0159] The polymerization product obtained as above is confirmed to
be a composite particle of polystyrene and polyester.
[0160] In the measurement of the molecular weight, the weight
average molecular weight Mw and the number average molecular weight
Mn are measured under the conditions described below by gel
permeation chromatography (GPC). The measurement is performed at a
temperature of 40.degree. C. by passing a solvent (tetrahydrofuran)
at a flow velocity of 1.2 ml/min, and injecting 3 mg as the sample
weight of a tetrahydrofuran sample solution having a concentration
of 0.2 g/20 ml. At the measurement of the molecular weight of a
sample, the measurement conditions are selected such that the
molecular weight of the sample is included in the range where a
logarithm and a count number of a molecular weight in a calibration
curve produced from several kinds of monodisperse polystyrene
standard samples form a straight line.
[0161] In this connection, the reliability of the measurement
results can be confirmed by the finding that an NBS706 polystyrene
standard sample measured under the above-described conditions
has:
[0162] weight average molecular weight Mw=28.8.times.10.sup.4
[0163] number average molecular weight Mn=13.7.times.10.sup.4
[0164] As for the column of GPC, a column satisfying the conditions
above, such as TSK-GEL and GMH (produced by Tosoh Corp.), is
used.
[0165] The melting point of the polyester is measured by using a
differential scanning calorimeter (DSC50, manufactured by Shimadzu
Corp.).
[0166] The viscoelasticity of the resin particle is measured by
using a rotary plate-type rheometer (RDA, 2RHIOS SYSTEM ver. 4.3.2,
manufactured by Rheometric Scientific F.E. Ltd.). After setting
each resin particle as a measuring object in a sample holder, the
measurement is performed at a temperature rising rate of 1.degree.
C./min, a frequency of 1 rad/sec, a distortion of 20% or less and a
detection torque within the range of the measurement compensation
value. An 8-mm sample holder or a 20-mm sample holder is used as
needed.
Example 2
[0167] TABLE-US-00003 <Preparation of Oil Phase 2>
1,9-Nonanediol (monomer melting point: 47.degree. C.) 6.0 parts by
weight 1,10-Decanedicarboxylic acid (monomer melting 6.0 parts by
weight point: 130.degree. C.) Diethyl fumarate (monomer melting
point: 2.degree. C.) 2.1 parts by weight (4 wt % of the total)
Styrene 35.0 parts by weight Stearyl methacrylate 1.66 parts by
weight Dodecanethiol 1.0 part by weight
[0168] These components are dissolved under heat at 130.degree. C.
to prepare a uniform oil phase. TABLE-US-00004 <Preparation of
Aqueous Phase 2> Dodecylbenzenesulfonic acid 1.66 parts by
weight Water 200 parts by weight
<Production of Resin Particle Liquid Dispersion 2>
[0169] The aqueous solution above is prepared and stirred in a
constant-temperature bath at 70.degree. C. for 1 hour. The aqueous
phase is charged into a 1 liter-volume vessel and mixed with the
oil phase and after stirring in Ultra-Turrax (manufactured by IKA
Works, Inc.) at 8,000 rpm for 3 minutes, the resulting emulsified
product is charged into a 500 ml-volume reactor equipped with a
stirrer and subjected to polycondensation at 70.degree. C. for 24
hours in a nitrogen atmosphere.
[0170] Thereafter, a material obtained by dissolving 1.1 parts by
weight of ammonium persulfate in 10 parts by weight of ion
exchanged water is added to the resin particle liquid dispersion
prepared above, and polymerization is further performed for 6 hours
in a nitrogen atmosphere. The obtained liquid dispersion is rapidly
cooled with ice water, as a result, the liquid dispersion
temperature became 2.5.degree. C. This liquid dispersion is sampled
in a small amount and the physical properties of the
polyester/polystyrene composite polymer are measured.
[0171] Weight average molecular weight of polystyrene by GPC:
48,200
[0172] Number average molecular weight of polyester by GPC:
2,100
[0173] Melting point of polyester: 61.degree. C.
[0174] Median diameter: 0.3 .mu.m
[0175] The viscoelasticity is measured in the same manner as Resin
Particle Liquid Dispersion 1.
[0176] The polymerization product obtained as above is confirmed to
be a composite particle of polystyrene and polyester.
Example 3
[0177] TABLE-US-00005 <Preparation of Oil Phase 3-1>
1,9-Nonanediol (monomer melting point: 47.degree. C.) 12.0 parts by
weight Sebacic acid (monomer melting point: 134.degree. C.) 16.0
parts by weight Styrene 25.0 parts by weight Dodecanethiol 1.35
parts by weight Stearyl methacrylate 2.5 parts by weight
[0178] These components are dissolved under heat at 130.degree. C.
to prepare a uniform oil phase. TABLE-US-00006 <Preparation of
Oil Phase 3-2> Hexamethylene diisocyanate 30.0 parts by weight
(30% of the total) Styrene 5.0 parts by weight <Preparation of
Aqueous Phase 3> Dodecylbenzenesulfonic acid 2.50 parts by
weight Water 100 parts by weight
<Production of Resin Particle Liquid Dispersion 3>
[0179] The aqueous solution above is prepared and stirred in a
constant-temperature bath at 85.degree. C. for 1 hour. The aqueous
phase is charged into a 1 liter-volume vessel and mixed with Oil
Phase 3-1 and after stirring in Ultra-Turrax (manufactured by IKA
Works, Inc.) at 8,000 rpm for 3 minutes, the resulting emulsified
product is charged into a 500 ml-volume reactor equipped with a
stirrer and subjected to polycondensation at 70.degree. C. for 24
hours in a nitrogen atmosphere.
[0180] After stirring Oil Phase 3-2 at room temperature for 30
minutes, Oil Phase 3-2 is added dropwise to the resin particle
liquid dispersion obtained above. Furthermore, 30 minutes after
that, a material obtained by dissolving 0.8 parts by weight of
ammonium persulfate in 10.0 parts by weight of ion exchanged water
is added, and polymerization is further performed for 6 hours in a
nitrogen atmosphere. The obtained resin particle liquid dispersion
is rapidly cooled with ice water, as a result, the liquid
dispersion temperature became 2.5.degree. C. This liquid dispersion
is sampled in a small amount and the physical properties of the
polyester/polystyrene composite polymer are measured.
[0181] Weight average molecular weight of polystyrene by GPC:
38,600
[0182] Number average molecular weight of polyester by GPC:
4,550
[0183] Melting point of polyester: 58.degree. C.
[0184] Median diameter: 0.36 .mu.m
[0185] The polymerization product obtained as above is confirmed to
be a composite particle of polystyrene and urethane-modified
polyester.
Example 4
[0186] TABLE-US-00007 <Preparation of Oil Phase 4-1>
1,12-Dodecanediol (monomer melting point: 6.8 parts by weight
84.degree. C.) 1,11-Undecanedicarboxylic acid (tridecane diacid,
8.2 parts by weight monomer melting point: 112.degree. C.) Styrene
35.0 parts by weight Dodecanethiol 1.0 part by weight Hexadecane
1.5 parts by weight
[0187] These components are dissolved under heat at 130.degree. C.
to prepare a uniform oil phase. TABLE-US-00008 <Preparation of
Oil Phase 4-2> Carbodilite V02L2 (produced by Nisshinbo 10.0
parts by weight Industries, Inc.) Styrene 5.0 parts by weight
<Preparation of Aqueous Phase 4> Scandium dodecylsulfate 7.2
parts by weight Water 150 parts by weight
<Production of Resin Particle Liquid Dispersion 4>
[0188] The aqueous solution above is prepared and stirred in a
constant-temperature bath at 75.degree. C. for 1 hour. The aqueous
phase is charged into a 1 liter-volume vessel and mixed with the
oil phase and after stirring in Ultra-Turrax (manufactured by IKA
Works, Inc.) at 8,000 rpm for 3 minutes, the resulting emulsified
product is charged into a 500 ml-volume reactor equipped with a
stirrer and subjected to polycondensation at 70.degree. C. for 24
hours in a nitrogen atmosphere. Subsequently, Oil Phase 4-2 is
added dropwise, and polycondensation is further performed at
70.degree. C. for 6 hours.
[0189] Thereafter, a material obtained by dissolving 1.1 parts by
weight of ammonium persulfate in 10 parts by weight of ion
exchanged water is added to the resin particle liquid dispersion
prepared above, and polymerization is further performed for 6 hours
in a nitrogen atmosphere. The obtained liquid dispersion is rapidly
cooled with ice water, as a result, the liquid dispersion
temperature became 2.5.degree. C. This liquid dispersion is sampled
in a small amount and the physical properties of the
polyester/polystyrene composite polymer are measured.
[0190] Weight average molecular weight of polystyrene by GPC:
53,300
[0191] Number average molecular weight of polyester by GPC:
3,050
[0192] Melting point of polyester: 71.degree. C.
[0193] Median diameter: 0.4 .mu.m
[0194] The viscoelasticity is measured in the same manner as Resin
Particle Liquid Dispersion 1.
[0195] The polymerization product obtained as above is confirmed to
be a composite particle of polystyrene and polyester.
Example 5
[0196] TABLE-US-00009 <Preparation of Oil Phase 5-1>
1,9-Nonanediol (monomer melting point: 47.degree. C.) 10.0 parts by
weight 1,10-Decanedicarboxylic acid (monomer melting 10.0 parts by
weight point: 130.degree. C.) Pyromellitic acid (monomer melting
point: 5 parts by weight 284.degree. C.) (9 wt % of the total)
Styrene 20.0 parts by weight Stearyl methacrylate 1.66 parts by
weight Dodecanethiol 1.0 part by weight
[0197] These components are dissolved under heat at 130.degree. C.
to prepare a uniform oil phase. TABLE-US-00010 <Preparation of
Oil Phase 5-2> Hexamethylene diisocyanate 5.0 parts by weight (9
wt % of all monomers) Styrene 5.0 parts by weight <Preparation
of Aqueous Phase 5> Dodecylbenzenesulfonic acid 1.66 parts by
weight Water 175 parts by weight
<Production of Resin Particle Liquid Dispersion 5>
[0198] The aqueous solution above is prepared and stirred in a
constant-temperature bath at 75.degree. C. for 1 hour. The aqueous
phase is charged into a 1 liter-volume vessel and mixed with the
oil phase and after stirring in Ultra-Turrax (manufactured by IKA
Works, Inc.) at 8,000 rpm for 3 minutes, the resulting emulsified
product is charged into a 500 ml-volume reactor equipped with a
stirrer and subjected to polycondensation at 70.degree. C. for 24
hours in a nitrogen atmosphere. Subsequently, Oil Phase 5-2 is
added dropwise, and polycondensation is further performed at
70.degree. C. for 6 hours.
[0199] Thereafter, a material obtained by dissolving 0.8 parts by
weight of ammonium persulfate in 10.0 parts by weight of ion
exchanged water is added to the resin particle liquid dispersion
prepared above, and polymerization is further performed for 6 hours
in a nitrogen atmosphere, as a result, a stable resin particle
liquid dispersion is obtained. This liquid dispersion is sampled in
a small amount and the physical properties of the
polyester/polystyrene composite polymer are measured.
[0200] Weight average molecular weight of polystyrene by GPC:
86,100
[0201] Number average molecular weight of polyester by GPC:
1,950
[0202] Melting point of polyester: 59.degree. C.
[0203] Median diameter: 0.42 .mu.m
[0204] The polymerization product obtained as above is confirmed to
be a composite particle of polystyrene and polyester.
Comparative Example 1
[0205] TABLE-US-00011 <Preparation of Oil Phase 6>
1,9-Nonanediol (monomer melting point: 47.degree. C.) 10.0 parts by
weight 1,10-Decanedicarboxylic acid (monomer melting 14.4 parts by
weight point: 130.degree. C.) Styrene 25.0 parts by weight Stearyl
methacrylate 1.66 parts by weight Dodecanethiol 1.0 part by
weight
[0206] These components are dissolved under heat at 130.degree. C.
to prepare a uniform oil phase. TABLE-US-00012 <Preparation of
Aqueous Phase 6> Dodecylbenzenesulfonic acid 1.66 parts by
weight Water 200 parts by weight
<Production of Resin Particle Liquid Dispersion 6>
[0207] The aqueous solution above is prepared and stirred in a
constant-temperature bath at 75.degree. C. for 1 hour. The aqueous
phase is charged into a 1 liter-volume vessel and mixed with the
oil phase and after stirring in Ultra-Turrax (manufactured by IKA
Works, Inc.) at 8,000 rpm for 3 minutes, the resulting emulsified
product is charged into a 500 ml-volume reactor equipped with a
stirrer and subjected to polycondensation at 70.degree. C. for 24
hours in a nitrogen atmosphere.
[0208] Thereafter, a material obtained by dissolving 0.8 parts by
weight of ammonium persulfate in 10.0 parts by weight of ion
exchanged water is added to the resin particle liquid dispersion
prepared above, and polymerization is further performed for 6 hours
in a nitrogen atmosphere. The obtained resin particle liquid
dispersion is rapidly cooled with ice water, as a result, the
liquid dispersion temperature became 2.5.degree. C. In this way, a
stable resin particle liquid dispersion is obtained. This liquid
dispersion is sampled in a small amount and the physical properties
of the polyester/polystyrene composite polymer are measured.
[0209] Weight average molecular weight of polystyrene by GPC:
44,400
[0210] Number average molecular weight of polyester by GPC:
1,750
[0211] Melting point of polyester: 60.degree. C.
[0212] Median diameter: 0.36 .mu.m
[0213] The polymerization product obtained as above is confirmed to
be a composite particle of polystyrene and polyester.
Comparative Example 2
[0214] TABLE-US-00013 <Preparation of Oil Phase 7-1>
1,9-Nonanediol (monomer melting point: 47.degree. C.) 12.0 parts by
weight Sebacic acid (monomer melting point: 134.degree. C.) 16.0
parts by weight Styrene 25.0 parts by weight Dodecanethiol 0.755
parts by weight Stearyl methacrylate 1.66 parts by weight
[0215] These components are dissolved under heat at 130.degree. C.
to prepare a uniform oil phase. TABLE-US-00014 <Preparation of
Oil Phase 7-2> Hexamethylene diisocyanate 3.0 parts by weight
(5% of all monomers) Styrene 5.0 parts by weight
[0216] TABLE-US-00015 <Preparation of Aqueous Phase 7>
Dodecylbenzenesulfonic acid 1.66 parts by weight Water 100 parts by
weight
<Production of Resin Particle Liquid Dispersion 7>
[0217] The aqueous solution above is prepared and stirred in a
constant-temperature bath at 85.degree. C. for 1 hour. The aqueous
phase is charged into a 1 liter-volume vessel and mixed with Oil
Phase 7-1 and after stirring in Ultra-Turrax (manufactured by IKA
Works, Inc.) at 8,000 rpm for 3 minutes, the resulting emulsified
product is charged into a 500 ml-volume reactor equipped with a
stirrer and subjected to polycondensation at 85.degree. C. for 24
hours in a nitrogen atmosphere.
[0218] After stirring Oil Phase 7-2 at room temperature for 30
minutes, Oil Phase 7-2 is added dropwise to the resin particle
liquid dispersion obtained above. Furthermore, 30 minutes after
that, a material obtained by dissolving 0.8 parts by weight of
ammonium persulfate in 10.0 parts by weight of ion exchanged water
is added, and polymerization is further performed for 6 hours in a
nitrogen atmosphere. The obtained resin particle liquid dispersion
is sampled in a small amount and the physical properties of the
urethane-modified polyester/polystyrene composite polymer are
measured.
[0219] Weight average molecular weight of polystyrene by GPC:
55,500
[0220] Number average molecular weight of polyester by GPC:
1,950
[0221] Melting point of polyester: 59.degree. C.
[0222] Median diameter: 0.51 .mu.m
[0223] The polymerization product obtained as above is confirmed to
be a composite particle of polystyrene and urethane-modified
polyester.
Comparative Example 3
[0224] TABLE-US-00016 <Preparation of Oil Phase 8>
1,9-Nonanediol (monomer melting point: 47.degree. C.) 10.0 parts by
weight 1,10-Decanedicarboxylic acid (monomer melting 10.0 parts by
weight point: 130.degree. C.) Styrene 25.0 parts by weight Diethyl
fumarate (monomer melting point: 2.degree. C.) 2.1 parts by weight
(4 wt % of the total) Dodecanethiol 0.75 parts by weight
[0225] These components are dissolved under heat at 130.degree. C.
to prepare a uniform oil phase. TABLE-US-00017 <Preparation of
Aqueous Phase 8> Para-toluenesulfonic acid 2.50 parts by weight
Cetyl alcohol 1.45 parts by weight Water 100 parts by weight
<Production of Resin Particle Liquid Dispersion 8>
[0226] The aqueous solution above is prepared and stirred in a
constant-temperature bath at 85.degree. C. for 1 hour. The aqueous
phase is charged into a 1 liter-volume vessel and mixed with the
oil phase and after stirring in Ultra-Turrax (manufactured by IKA
Works, Inc.) at 8,000 rpm for 3 minutes, the resulting emulsified
product is charged into a 500 ml-volume reactor equipped with a
stirrer and subjected to polycondensation at 85.degree. C. for 24
hours in a nitrogen atmosphere. Thereafter, a material obtained by
dissolving 0.8 parts by weight of ammonium persulfate in 10.0 parts
by weight of ion exchanged water is added, and polymerization is
further performed for 6 hours in a nitrogen atmosphere. The
obtained liquid dispersion is rapidly cooled with ice water, as a
result, the liquid dispersion temperature became 2.5.degree. C.
This liquid dispersion is sampled in a small amount and the
physical properties of the polyester/polystyrene composite polymer
are measured.
[0227] Weight average molecular weight of polystyrene by GPC: 147,
100
[0228] Number average molecular weight of polyester by GPC:
2,500
[0229] Melting point of polyester: 62.degree. C.
[0230] Median diameter: 0.51 .mu.m
[0231] The polymerization product obtained as above is confirmed to
be a composite particle of polystyrene and urethane-modified
polyester.
Comparative Example 4
[0232] TABLE-US-00018 <Preparation of Oil Phase 9>
1,9-Nonanediol (monomer melting point: 47.degree. C.) 6.0 parts by
weight 1,10-Decanedicarboxylic acid (monomer melting 6.0 parts by
weight point: 130.degree. C.) Diethyl fumarate (monomer melting
point: 2.degree. C.) 2.1 parts by weight (20 wt % of the total)
Styrene 35.0 parts by weight Stearyl methacrylate 1.66 parts by
weight Dodecanethiol 1.0 part by weight
[0233] These components are dissolved under heat at 130.degree. C.
to prepare a uniform oil phase. TABLE-US-00019 <Preparation of
Aqueous Phase 9> Dodecylbenzenesulfonic acid 1.66 parts by
weight Water 200 parts by weight
<Production of Resin Particle Liquid Dispersion 9>
[0234] The aqueous solution above is prepared and stirred in a
constant-temperature bath at 70.degree. C. for 1 hour. The aqueous
phase is charged into a 1 liter-volume vessel and mixed with the
oil phase and after stirring in Ultra-Turrax (manufactured by IKA
Works, Inc.) at 8,000 rpm for 3 minutes, the resulting emulsified
product is charged into a 500 ml-volume reactor equipped with a
stirrer and subjected to polycondensation at 40.degree. C. for 24
hours in a nitrogen atmosphere.
[0235] Thereafter, a material obtained by dissolving 1.1 parts by
weight of ammonium persulfate in 10 parts by weight of ion
exchanged water is added to the resin particle liquid dispersion
prepared above, and polymerization is further performed for 6 hours
in a nitrogen atmosphere. The obtained liquid dispersion is rapidly
cooled with ice water, as a result, the liquid dispersion
temperature became 2.5.degree. C. This liquid dispersion is sampled
in a small amount and the physical properties of the
polyester/polystyrene composite polymer are measured.
[0236] Weight average molecular weight of polystyrene by GPC:
152,200
[0237] Number average molecular weight of polyester by GPC:
1,500
[0238] Melting point of polyester: 51.degree. C.
[0239] Median diameter: 3.2 .mu.m
[0240] The viscoelasticity is measured in the same manner as Resin
Particle Liquid Dispersion 1.
[0241] The polymerization product obtained as above is confirmed to
be a composite particle of polystyrene and polyester.
Comparative Example 5
[0242] TABLE-US-00020 <Preparation of Oil Phase 10>
1,9-Nonanediol (monomer melting point: 47.degree. C.) 6.0 parts by
weight Adipic acid (monomer melting point: 152.degree. C.) 4.0
parts by weight Diethyl fumarate (monomer melting point: 2.degree.
C.) 2.1 parts by weight (20 wt % of the total) Styrene 35.0 parts
by weight Stearyl methacrylate 1.66 parts by weight Dodecanethiol
1.0 part by weight
[0243] These components are dissolved under heat at 130.degree. C.
to prepare a uniform oil phase. TABLE-US-00021 <Preparation of
Aqueous Phase 10> Dodecylbenzenesulfonic acid 1.66 parts by
weight Water 200 parts by weight
<Production of Resin Particle Liquid Dispersion 10>
[0244] The aqueous solution above is prepared and stirred in a
constant-temperature bath at 100.degree. C. for 1 hour. The aqueous
phase is charged into a 1 liter-volume vessel and mixed with the
oil phase and after stirring in Ultra-Turrax (manufactured by IKA
Works, Inc.) at 8,000 rpm for 3 minutes, the resulting emulsified
product is charged into a 500 ml-volume reactor equipped with a
stirrer and subjected to polycondensation at 40.degree. C. for 24
hours in a nitrogen atmosphere.
[0245] Thereafter, a material obtained by dissolving 1.1 parts by
weight of ammonium persulfate in 10 parts by weight of ion
exchanged water is added to the resin particle liquid dispersion
prepared above, and polymerization is further performed for 6 hours
in a nitrogen atmosphere. The obtained liquid dispersion is rapidly
cooled with ice water, as a result, the liquid dispersion
temperature became 2.5.degree. C. This liquid dispersion is sampled
in a small amount and the physical properties of the
polyester/polystyrene composite polymer are measured.
[0246] Weight average molecular weight of polystyrene by GPC:
109,200
[0247] Number average molecular weight of polyester by GPC:
1,250
[0248] Melting point of polyester: 49.degree. C.
[0249] Median diameter: 1.2 .mu.m
[0250] The viscoelasticity is measured in the same manner as Resin
Particle Liquid Dispersion 1.
[0251] The polymerization product obtained as above is confirmed to
be a composite particle of polystyrene and polyester.
TABLE-US-00022 TABLE 1 Example Comparative Example 1 2 3 4 5 1 2 3
4 5 Median 0.4 0.3 0.36 0.4 0.42 0.36 0.51 0.51 3.2 1.2
diameter(.mu.m) Tm (.degree. C.) 59 61 58 71 59 60 59 62 51 49 Tc
(.degree. C.) 70 70 70 70 70 70 85 85 40 100 Th (.degree. C.) 130
130 134 112 284 130 134 130 130 152 Number average 2250 2100 4550
3050 1950 1750 1950 2500 1500 1250 molecular weight Mn (polyester)
GL (30) (Pa) 4.1 .times. 10.sup.8 1.2 .times. 10.sup.8 3.3 .times.
10.sup.8 7.5 .times. 10.sup.7 9.3 .times. 10.sup.7 4.8 .times.
10.sup.6 7.5 .times. 10.sup.6 8.8 .times. 10.sup.6 2.5 .times.
10.sup.5 5.7 .times. 10.sup.6 .DELTA.T (1 .times. 10.sup.6
.fwdarw.1 .times. 10.sup.4) 7.3 8.4 5.9 7.3 10.5 8.0 6.9 9.4
immeasurable 13.5 (.degree. C.) .DELTA.T (1 .times. 10.sup.7
.fwdarw.1 .times. 10.sup.3) 15.8 17.1 14.6 16.7 18.2 immeas-
immeas- immeas- immeasurable immeas- (.degree. C.) urable urable
urable urable |logG'(Tm + 20) - 0.68 1.02 0.71 0.89 1.11 2.30 1.80
1.25 1.75 2.0 logG'(Tm + 50)|
[0252] TABLE-US-00023 (Preparation of Releasing agent Particle
Liquid Dispersion (W1)) Polyethylene wax (Polywax 725, produced by
30 parts by weight Toyo-Petrolite K.K., melting point: 103.degree.
C.) Cationic surfactant (Sanizol B50, Kao Corp.) 3 parts by weight
Ion exchanged water 67 parts by weight
[0253] These components are thoroughly dispersed in a homogenizer
(Ultra-Turrax T50, manufactured by IKA Works, Inc.) under heating
at 95.degree. C. and then dispersed in a pressure jet-type
homogenizer (Gaulin homogenizer, manufactured by Gaulin) to prepare
Releasing Agent Particle Liquid Dispersion (W1). The number average
particle diameter D.sub.50n of the releasing agent particles in the
obtained liquid dispersion is 310 nm. Thereafter, ion exchanged
water is added to adjust the solid concentration of the liquid
dispersion to 30%. TABLE-US-00024 (Preparation of Magenta Pigment
Liquid Dispersion (M1)) Magenta pigment (PR122 (quinacridone), 20
parts by weight produced by Dainichiseika Color & Chemicals
Mfg. Co., Ltd.) Anionic surfactant (Neogen R, produced by Daiichi 2
parts by weight Kogyo Seiyaku Co., Ltd.) Ion exchanged water 78
parts by weight
[0254] These components are dispersed in a homogenizer
(Ultra-Turrax T50, manufactured by IKA Works, Inc.) at 3,000 rpm
for 2 minutes, thereby causing the pigment to get affinity for
water, and further dispersed at 5,000 rpm for 10 minutes. The
resulting dispersion is stirred for one day and night by an
ordinary stirrer to effect defoaming and then dispersed under a
pressure of 240 MPa for about 1 hour by using a high pressure
impact-type dispersing machine Altimizer (HJP30006, manufactured by
Sugino Machine Ltd.) to obtain Magenta Pigment Liquid Dispersion
(M1). The number average particle diameter D.sub.50n of the pigment
in the liquid dispersion is 106 nm. Thereafter, ion exchanged water
is added to adjust the solid concentration of the liquid dispersion
to 15%. TABLE-US-00025 (Preparation of Cyan Pigment Liquid
Dispersion (C1)) Cyan pigment (PB15:3, produced by Dainichiseika 20
parts by weight Color & Chemicals Mfg. Co., Ltd.) Anionic
surfactant (Neogen R, produced by Daiichi 2 parts by weight Kogyo
Seiyaku Co., Ltd.) Ion exchanged water 78 parts by weight
[0255] A cyan pigment liquid dispersion is prepared in the same
manner as Magenta Pigment Liquid Dispersion (M1) except for using
the above-described components. The number average particle
diameter D.sub.50n of the pigment in the liquid dispersion is 121
nm. Thereafter, ion exchanged water is added to adjust the solid
concentration of the liquid dispersion to 15%. TABLE-US-00026
(Preparation of Yellow Pigment Liquid Dispersion (Y1)) Yellow
pigment (PY74, produced by Clariant 20 parts by weight Japan)
Anionic surfactant (Neogen R, produced by Daiichi 2 parts by weight
Kogyo Seiyaku Co., Ltd.) Ion exchanged water 78 parts by weight
[0256] A yellow pigment liquid dispersion is prepared in the same
manner as Magenta Pigment Liquid Dispersion (M1) except for using
the above-described components. The number average particle
diameter D.sub.50n of the pigment in the liquid dispersion is 118
nm. Thereafter, ion exchanged water is added to adjust the solid
concentration of the liquid dispersion to 15%. TABLE-US-00027
(Preparation of Black Pigment Liquid Dispersion (K1)) Carbon black
(Regal 330, produced by Cabot Inc.) 20 parts by weight Anionic
surfactant (Neogen R, produced by Daiichi 2 parts by weight Kogyo
Seiyaku Co., Ltd.) Ion exchanged water 78 parts by weight
[0257] A black pigment liquid dispersion is prepared in the same
manner as Magenta Pigment Liquid Dispersion (M1) except for using
the above-described components. The number average particle
diameter D.sub.50n, of the pigment in the liquid dispersion is 120
nm. Thereafter, ion exchanged water is added to adjust the solid
concentration of the liquid dispersion to 15%. TABLE-US-00028
(Preparation of Resin Particle Liquid Dispersion A: non-crystalline
vinyl-based resin latex) Styrene 460 parts by weight n-Butyl
acrylate 140 parts by weight Acrylic acid 12 parts by weight
Dodecanethiol 9 parts by weight
[0258] These components are mixed and dissolved to prepare a
solution.
[0259] Separately, 12 parts by weight of an anionic surfactant
(Dowfax, produced byDow Chemical, Inc.) is dissolved in 250 parts
by weight of ion exchanged water, and the solution prepared above
is added thereto, followed by dispersion and emulsification in a
flask (Monomer Emulsion A).
[0260] Furthermore, 1 part by weight of an anionic surfactant
(Dowfax, produced by Dow Chemical, Inc.) is dissolved in 555 parts
by weight of ion exchanged water, and the resulting solution is
charged into a polymerization flask.
[0261] The polymerization flask is tightly plugged and after
connecting a reflux tube thereto, the polymerization flask is
heated to 75.degree. C. on a water bath with slow stirring while
injecting nitrogen, and this condition is maintained.
[0262] 9 Parts by weight of ammonium persulfate is dissolved in 43
parts by weight of ion exchanged water, and the resulting solution
is added dropwise to the polymerization flask through a metering
pump over 20 minutes, and then Monomer Emulsion A is also added
dropwise through a metering pump over 200 minutes.
[0263] Thereafter, the polymerization flask is maintained at
75.degree. C. for 3 hours while continuing slowly stirring to
complete the polymerization.
[0264] In this way, Anionic Resin Particle Liquid Dispersion A
containing resin particles with a median diameter of 230 nm, a
glass transition point of 53.5.degree. C. and a weight average
molecular weight of 36,000, and having a solid content of 42% is
obtained.
Example 6
Production of toner using Resin Particle Liquid Dispersion 1
[0265] TABLE-US-00029 (Production of Black Toner (Toner K1)) Resin
Particle Liquid Dispersion 1 120 parts by weight Resin Particle
Liquid Dispersion A 40 parts by weight Releasing Agent Particle
Liquid Dispersion (W1) 33 parts by weight Black Pigment Liquid
Dispersion (K1) 60 parts by weight An aqueous 10 mass %
polyaluminum chloride 15 parts by weight solution (PAC100W,
produced by Asada Kagaku K.K.) An aqueous 1% nitric acid solution 3
parts by weight
[0266] These components are dispersed by using a homogenizer
(Ultra-Turrax T50, manufactured by IKA Works, Inc.) at 5,000 rpm
for 3 minutes in a round-shaped stainless steel-made flask, and
then a lid equipped with a stirrer having magnetic seal, a
thermometer and a pH meter is put on the flask. Thereafter, a
mantle heater for heating is set, and the flask is heated to
57.degree. C. at a rate of 1.degree. C./min with stirring under
appropriate control to a minimum rotation number necessary for
stirring the entire liquid dispersion in the flask. The temperature
is kept at 57.degree. C. for 30 minutes, and the particle diameter
of the aggregate particles is confirmed by a Coulter counter (TA
II, manufactured bybeckman-Coulter Corp.). Immediately after
stopping of the temperature elevation, 50 parts by weight of Resin
Particle Liquid Dispersion 1 is added, and the mixture is kept for
30 minutes. Subsequently, an aqueous sodium hydroxide solution is
added until the pH of the system became 6.5, and then the mixture
is heated to 97.degree. C. at 1.degree. C./min. After the elevation
of temperature, an aqueous nitric acid solution is added to adjust
the pH of the system to 5.0, and the mixture is kept for 10 hours
to coalesce aggregate particles under heat. Thereafter, the
temperature of the system is lowered to 50.degree. C., and an
aqueous sodium hydroxide solution is added to adjust the pH to
12.0. The obtained mixture is kept for 10 minutes, then taken out
from the flask, thoroughly filtrated and flow-washed by using ion
exchanged water and further dispersed in ion exchanged water to
give a solid content of 10 wt %. After adjusting the pH to 3.0 by
adding a nitric acid, the mixture is stirred for 10 minutes and
again thoroughly filtrated and flow- is hed by using ion exchanged
water. The resulting slurry is freeze-dried to obtain a black toner
(Toner K1).
[0267] Thereafter, silica (SiO.sub.2) particles subjected to a
surface hydrophobing treatment with hexamethyldisilazane
(hereinafter sometimes simply referred to as "HMDS") and having an
average primary particle diameter of 40 nm, and metatitanic acid
compound particles having an average primary particle diameter of
20 nm, which is a reaction product of metatitanic acid and
isobutyltrimethoxysilane, are added each in an amount of 1 wt % to
the black toner obtained above and mixed in a Henschel mixer to
produce a black external addition toner.
[0268] The accumulated volume average particle diameter D.sub.50
and volume average particle size distribution index GSDv of the
thus produced toner are measured by a laser diffraction-type
particle size distribution measuring device (LA-700, manufactured
by Horiba Ltd.). The surface of this toner is observed through a
scanning electron microscope (SEM) and the cross section thereof is
observed by a transmission-type electron microscope (TEM), as a
result, the resin, pigment and other additives are fused as
intended and pores or irregularities are not observed. The
dispersed state of the pigment is also good. Furthermore, the shape
of the toner particle is observed by Luzex and it is confirmed that
the toner particle has a potato shape with a shape factor SF1 of
131.
Example 7
Production of Cyan Toner (Toner C1))
[0269] A cyan toner is obtained in the same manner as the black
toner produced above, except for changing Black Pigment Liquid
Dispersion (K1) to a cyan pigment liquid dispersion, and the
accumulated volume average particle diameter D.sub.50 and volume
average particle size distribution index GSDv are measured. Also,
the surface and cross section of this toner are observed in the
same manner as in Example 6, as a result, it is confirmed that the
fused state of toner, the dispersed state of additives and the
appearance are good and the toner particle has a potato shape with
a shape factor SF1 of 130. Similarly to Example 6, external
additives are externally added to this toner to obtain a cyan
external addition toner.
Example 8
Production of Yellow Toner (Toner Y1))
[0270] A yellow toner is obtained in the same manner as the black
toner produced above, except for changing Black Pigment Liquid
Dispersion (K1) to a yellow pigment liquid dispersion, and the
accumulated volume average particle diameter D.sub.50 and volume
average particle size distribution index GSDv are measured. Also,
the surface and cross section of this toner are observed in the
same manner as in Example 6, as a result, it is confirmed that the
fused state of toner, the dispersed state of additives and the
appearance are good and the toner particle has a potato shape with
a shape factor SF1 of 131. Similarly to Example 6, external
additives are externally added to this toner to obtain a yellow
external addition toner.
Example 9
Production of Magenta Toner (Toner M1))
[0271] A magenta toner is obtained in the same manner as the black
toner produced above, except for changing Black Pigment Liquid
Dispersion (K1) to a magenta pigment liquid dispersion, and the
accumulated volume average particle diameter D.sub.50 and volume
average particle size distribution index GSDv are measured. Also,
the surface and cross section of this toner are observed in the
same manner as in Example 6, as a result, it is confirmed that the
fused state of toner, the dispersed state of additives and the
appearance are good and the toner particle has a potato shape with
a shape factor SF1 of 132. Similarly to Example 6, external
additives are externally added to this toner to obtain a magenta
external addition toner.
Example 10
Production of Toner using Resin Particle Liquid Dispersion 2
[0272] Cyan Toner (C2) is obtained in the same manner as in Example
7 except for changing the resin particle liquid dispersion to Resin
Particle Liquid Dispersion 2. The surface and cross section of this
toner are observed in the same manner as in Example 6, as a result,
it is confirmed that the fused state of toner, the dispersed state
of additives and the appearance are good and the toner particle has
a potato shape with a shape factor SF1 of 130. Similarly to Example
6, external additives are externally added to this toner to obtain
a cyan external addition toner.
Example 11
Production of Toner using Resin Particle Liquid Dispersion 3
[0273] Cyan Toner (C3) is obtained in the same manner as in Example
7 except for changing the resin particle liquid dispersion to Resin
Particle Liquid Dispersion 3. The surface and cross section of this
toner are observed in the same manner as in Example 6, as a result,
it is confirmed that the fused state of toner, the dispersed state
of additives and the appearance are good and the toner particle has
a potato shape with a shape factor SF1 of 131. Similarly to Example
6, external additives are externally added to this toner to obtain
a cyan external addition toner.
Example 12
Production of Toner using Resin Particle Liquid Dispersion 4
[0274] Cyan Toner (C4) is obtained in the same manner as in Example
7 except for changing the resin particle liquid dispersion to Resin
Particle Liquid Dispersion 4. The surface and cross section of this
toner are observed in the same manner as in Example 6, as a result,
it is confirmed that the fused state of toner, the dispersed state
of additives and the appearance are good and the toner particle had
a potato shape with a shape factor SF1 of 129. Similarly to Example
6, external additives are externally added to this toner to obtain
a cyan external addition toner.
Example 13
Production of Toner using Resin Particle Liquid Dispersion 5
[0275] Cyan Toner (C5) is obtained in the same manner as in Example
7 except for changing the resin particle liquid dispersion to Resin
Particle Liquid Dispersion 5 and changing the blending amount of
the resin particle liquid dispersion as follows. The surface and
cross section of this toner are observed in the same manner as in
Example 6, as a result, it is confirmed that the fused state of
toner, the dispersed state of additives and the appearance are good
and the toner particle has a potato shape with a shape factor SF1
of 130. Similarly to Example 6, external additives are externally
added to this toner to obtain a cyan external addition toner.
Comparative Example 6
Production of Toner using Resin Particle Liquid Dispersion 6
[0276] Black Toner (K6) is obtained in the same manner as in
Example 6 except for changing the resin particle liquid dispersion
to Resin Particle Liquid Dispersion 6. The surface and cross
section of this toner are observed in the same manner as in Example
6, as a result, it is confirmed that the fused state of toner, the
dispersed state of additives and the appearance are good and the
toner particle has a potato shape with a shape factor SF1 of 131.
Similarly to Example 6, external additives are externally added to
this toner to obtain a black external addition toner.
Comparative Example 7
[0277] Cyan Toner (C6) is obtained in the same manner as in
Comparative Example 6 except for changing the pigment liquid
dispersion to a cyan pigment liquid dispersion. The surface and
cross section of this toner are observed in the same manner as in
Example 6, as a result, it is confirmed that the fused state of
toner, the dispersed state of additives and the appearance are good
and the toner particle has a potato shape with a shape factor SF1
of 132. Similarly to Example 6, external additives are externally
added to this toner to obtain a cyan external addition toner.
Comparative Example 8
[0278] Yellow Toner (Y6) is obtained in the same manner as in
Comparative Example 6 except for changing the pigment liquid
dispersion to a yellow pigment liquid dispersion. The surface and
cross section of this toner are observed in the same manner as in
Example 6, as a result, it is confirmed that the fused state of
toner, the dispersed state of additives and the appearance are good
and the toner particle has a potato shape with a shape factor SF1
of 132. Similarly to Example 6, external additives are externally
added to this toner to obtain a yellow external addition toner.
Comparative Example 9
[0279] Magenta Toner (6) is obtained in the same manner as in
Comparative Example 6 except for changing the pigment liquid
dispersion to a magenta pigment liquid dispersion. The surface and
cross section of this toner are observed in the same manner as in
Example 6, as a result, it is confirmed that the fused state of
toner, the dispersed state of additives and the appearance are good
and the toner particle has a potato shape with a shape factor SF1
of 130. Similarly to Example 6, external additives are externally
added to this toner to obtain a magenta external addition
toner.
Comparative Example 10
Production of Toner using Resin Particle Liquid Dispersion 7
[0280] Cyan Toner (C7) is obtained in the same manner as in
Comparative Example 7 except for changing the resin particle liquid
dispersion to Resin Particle Liquid Dispersion 7. The surface and
cross section of this toner are observed in the same manner as in
Example 6, as a result, it is confirmed that the fused state of
toner or the dispersed state of additives is non-uniform and
although the toner particle has a potato shape with a shape factor
of 128, the fluctuation is large. Similarly to Example 6, external
additives are externally added to this toner to obtain a cyan
external addition toner.
Comparative Example 11
Production of Toner using Resin Particle Liquid Dispersion 8
[0281] Cyan Toner (C8) is obtained in the same manner as in
Comparative Example 7 except for changing the resin particle liquid
dispersion to Resin Particle Liquid Dispersion 8. The surface and
cross section of this toner are observed in the same manner as in
Example 6, as a result, it is confirmed that the fused state of
toner, the dispersed state of additives and the appearance are good
and the toner particle has a potato shape with a shape factor of
130 but the fluctuation is large. Similarly to Example 6, external
additives are externally added to this toner to obtain a cyan
external addition toner.
Comparative Example 12
Production of Toner using Resin Particle Liquid Dispersion 9
[0282] Cyan Toner (C9) is obtained in the same manner as in
Comparative Example 7 except for changing the resin particle liquid
dispersion to Resin Particle Liquid Dispersion 9. The surface and
cross section of this toner are observed in the same manner as in
Example 6, as a result, it is confirmed that the fused state of
toner or the dispersed state of additives is non-uniform and
although the toner particle has a potato shape with a shape factor
of 125, the fluctuation is large. Similarly to Example 6, external
additives are externally added to this toner to obtain a cyan
external addition toner.
Comparative Example 13
Production of Toner using Resin Particle Liquid Dispersion 10
[0283] Cyan Toner (C10) is obtained in the same manner as in
Comparative Example 7 except for changing the resin particle liquid
dispersion to Resin Particle Liquid Dispersion 10. The surface and
cross section of this toner are observed in the same manner as in
Example 6, as a result, it is confirmed that the fused state of
toner or the dispersed state of additives is non-uniform and the
toner particle has a potato shape with a shape factor of 124.
Similarly to Example 6, external additives are externally added to
this toner to obtain a cyan external addition toner.
Comparative Example 14
Production of Toner using Resin Particle Liquid Dispersion A
[0284] Cyan Toner (C-A) is obtained in the same manner as in
Comparative Example 7 except for changing the resin particle liquid
dispersion to Resin Particle Liquid Dispersion A, that is,
constituting the resin particle liquid dispersions entirely by
Resin Particle Liquid Dispersion A. The surface and cross section
of this toner are observed in the same manner as in Example 6, as a
result, it is confirmed that the fused state of toner, the
dispersed state of additives and the appearance are good and the
toner particle has a potato shape with a shape factor of 131.
Similarly to Example 6, external additives are externally added to
this toner to obtain a cyan external addition toner.
[Production of Carrier]
[0285] A methanol solution containing 0.1 part by weight of
.gamma.-aminopropyltriethoxysilane is added to 100 parts by weight
of Cu--Zn ferrite particles having a volume average particle
diameter of 40 .mu.m and after coating in a kneader, methanol is
removed by distillation. The obtained silane compound is heated at
120.degree. C. for 2 hours and thereby completely hardened. The
particles obtained are mixed with a perfluorooctylethyl
methacrylate-methyl methacrylate copolymer (copolymerization ratio:
40:60) dissolved in toluene, and the resulting mixture is subjected
to a vacuum kneader to produce a resin-coated carrier in which the
amount of the perfluorooctylethyl methacrylate-methyl methacrylate
copolymer coating is 0.5 wt %.
[Production of Developer]
[0286] 100 Parts by weight of the thus-obtained resin-coated
carrier is mixed with 4 parts by weight of each of the toners
produced above to produce an electrostatic image developer. These
developers are used as the developer in the following
evaluations.
[0287] With respect to the toners and developers obtained as above,
the thermal storability of toner is evaluated, and the minimum
fixing temperature and temperature of generating image
deterioration (hereinafter referred to as "uneven permeation") due
to permeation phenomenon are determined by evaluating the fixed
image with an eye.
<Measurement of Minimum Fixing Temperature and Uneven
Permeation-Generating Temperature>
[0288] The minimum fixing temperature is defined as the temperature
of bringing disappearance of image deterioration (hereinafter
referred to as "uneven density") caused due to insufficient melting
of toner. The uneven permeation-generating temperature is defined
as the temperature of causing generation of a white shining spot in
a solid image.
[0289] These are evaluated by using modified Docu Centre Color
500CP manufactured by Fuji Xerox Co., Ltd., which is modified to
make variable the roll temperature of the fixing unit, at a process
speed of 180 mm/sec. The paper sheet used is J coat paper produced
by Fuji Xerox Office Supply Co., Ltd. for the measurement of the
minimum fixing temperature, and ST paper and WR-100 paper (both
recycled paper, produced by Fuji Xerox Office Supply Co., Ltd.) for
the measurement of the uneven permeation-generating
temperature.
[0290] In general, it is known that uneven permeation is more
readily generated as the paper density is lower or the smoothness
of paper surface is poorer. Accordingly, when thin paper with low
paper density or recycled paper (for example, "ST paper", "WR-100
paper" and "Green 100 paper", produced by Fuji Xerox Office Supply
Co., Ltd.) having blended therein waste paper with poor smoothness
of paper surface is used, the fixing temperature range may become
narrow.
<Evaluation of Thermal Storability (Heat Blocking Resistance) of
Toner>
[0291] First, 5 g of the toner is left standing in a chamber at
40.degree. C. and 50% RH for 17 hours. After returning the
temperature to room temperature, 2 g of the toner is charged into a
mesh having a sieve opening of 45 .mu.m and vibrated under fixed
conditions. The weight of the toner remaining on the mesh is
measured, and the weight ratio to the amount charged is calculated.
The obtained numerical value is used as the index for heat blocking
resistance of the toner.
[0292] The thermal storability of the toner is rated as
follows:
[0293] A: the index of heat blocking resistance is 3% or less;
[0294] B: more than 3% to 5%;
[0295] C: more than 5% to 10%; and
[0296] D: more than 10%. TABLE-US-00030 TABLE 2 Minimum Uneven
Permeation- Accumulated Volume Volume Average Fixing Generating
Thermal Resin Liquid Average Particle Particle Temperature
Temperature (.degree. C.) Storability of Toner Dispersion Diameter
D.sub.50 (.mu.m) Distribution GSDv (.degree. C.) S Paper WR Paper
Toner Example 6 K1 1 5.8 1.22 110 175 165 A Example 7 C1 1 5.8 1.24
115 170 160 A Example 8 Y1 1 6.0 1.23 110 170 165 A Example 9 M1 1
5.9 1.23 110 175 165 A Example 10 C2 2 5.8 1.25 115 170 160 A
Example 11 C3 3 5.7 1.22 105 160 155 A Example 12 C4 4 6.1 1.26 110
165 155 B Example 13 C5 5 5.9 1.24 115 170 160 A Comparative K6 6
5.9 1.23 120 150 140 D Example 6 Comparative C6 6 5.8 1.25 120 155
135 D Example 7 Comparative Y6 6 5.9 1.22 115 155 145 C Example 8
Comparative M6 6 5.9 1.23 120 155 130 D Example 9 Comparative C7 7
5.7 1.25 110 150 135 C Example 10 Comparative C8 8 5.8 1.22 120 155
140 C Example 11 Comparative C9 9 5.9 1.41 135 145 140 D Example 12
Comparative C10 10 6.1 1.26 130 155 145 C Example 13 Comparative
C-A A 5.8 1.22 145 170 165 A Example 14
[0297] As seen from these results, the electrostatic image
developing toner produced by using the resin particle liquid
dispersion of the present invention has stable toner storability
and a wide fixing possible temperature region independent of the
paper used. Furthermore, the production method for the toner
enables the production by a consistent process with energy saving
and ensures a toner having high storability and excellent particle
size controllability, as compared with the process of producing a
toner by using a conventional polycondensable resin.
[0298] According to the present invention, a resin particle liquid
dispersion for an electrostatic image developing toner, having a
viscoelasticity, a particle diameter and a particle diameter
distribution suitable for a toner, can be provided.
[0299] Also, according to the present invention, an electrostatic
image developing toner assured of a stable toner storability and a
wide fixing possible temperature region independent of the paper
used can be provided. Furthermore, a production process of an
electrostatic image developing toner, which enables the production
by a consistent process with energy saving, can be provided.
[0300] The entire disclosure of Japanese Patent Application No.
2005-209848 filed on Jul. 20, 2005 including specification, claims,
drawings and abstract is incorporated herein by reference in its
entirely.
* * * * *