U.S. patent application number 10/112769 was filed with the patent office on 2003-02-06 for toner composition and method for manufacturing the toner composition.
Invention is credited to Emoto, Shigeru, Sugiyama, Tsunemi, Tomita, Masami, Yamashita, Hiroshi.
Application Number | 20030027066 10/112769 |
Document ID | / |
Family ID | 18956268 |
Filed Date | 2003-02-06 |
United States Patent
Application |
20030027066 |
Kind Code |
A1 |
Yamashita, Hiroshi ; et
al. |
February 6, 2003 |
Toner composition and method for manufacturing the toner
composition
Abstract
A toner composition including toner particles, wherein the toner
particles are prepared by a method in which toner constituents
including at least a binder resin and a colorant are kneaded upon
application of heat to prepare a toner constituent mixture; the
toner constituent mixture is dissolved or swelled in an organic
solvent capable of dissolving or swelling at least the binder resin
to prepare an oil phase liquid; the oil phase liquid is emulsified
in an aqueous liquid to prepare an emulsion; the emulsion is
coagulated; and then the coagulated emulsion is dried to prepare
the toner particles.
Inventors: |
Yamashita, Hiroshi;
(Numazu-shi, JP) ; Tomita, Masami; (Numazu-shi,
JP) ; Emoto, Shigeru; (Numazu-shi, JP) ;
Sugiyama, Tsunemi; (Numazu-shi, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Family ID: |
18956268 |
Appl. No.: |
10/112769 |
Filed: |
April 2, 2002 |
Current U.S.
Class: |
430/105 ;
430/109.1; 430/109.3; 430/109.4; 430/137.14 |
Current CPC
Class: |
G03G 9/081 20130101;
G03G 9/0804 20130101; G03G 9/08782 20130101; C08J 3/14 20130101;
G03G 9/08711 20130101 |
Class at
Publication: |
430/105 ;
430/137.14; 430/109.4; 430/109.1; 430/109.3 |
International
Class: |
C08J 003/215; G03G
009/08 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 2, 2001 |
JP |
2001-103171 |
Claims
What is claimed as new and desired to be secured by Letters Patent
of the United States is:
1. A toner composition comprising toner particles, wherein the
toner particles are prepared by a method selected from the group
consisting of: a first method comprising: kneading toner
constituents comprising at least a binder resin and a colorant upon
application of heat to prepare a toner constituent mixture;
dissolving the toner constituent mixture in an organic solvent
capable of dissolving at least the binder resin to prepare an oil
phase liquid; emulsifying the oil phase liquid in an aqueous liquid
to prepare an emulsion; coagulating the emulsion; and drying the
coagulated emulsion to prepare the toner particles; a second method
comprising: kneading toner constituents comprising at least a
binder resin and a colorant upon application of heat to prepare a
toner constituent mixture; swelling the toner constituent mixture
in an organic solvent capable of swelling at least the binder resin
to prepare an oil phase liquid; emulsifying the oil phase liquid in
an aqueous liquid to prepare an emulsion; coagulating the emulsion;
and drying the coagulated emulsion to prepare the toner particles;
a third method comprising: kneading at least a colorant and a
binder resin to prepare a master batch colorant; dispersing toner
constituents comprising at least the master batch colorant and a
resin in an organic solvent capable of dissolving the resin to
prepare an oil phase liquid, wherein the resin is the same as the
binder resin or different from the binder resin; emulsifying the
oil phase liquid in an aqueous liquid to prepare an emulsion;
coagulating the emulsion; and drying the coagulated emulsion to
prepare the toner particles; a fourth method comprising: kneading
at least a colorant and a binder resin to prepare a master batch
colorant; dispersing toner constituents comprising at least the
master batch colorant and a resin in an organic solvent capable of
swelling the resin to prepare an oil phase liquid, wherein the
resin is the same as the binder resin or different from the binder
resin; emulsifying the oil phase liquid in an aqueous liquid to
prepare an emulsion; coagulating the emulsion; and drying the
coagulated emulsion to prepare the toner particles; and a fifth
method comprising: dispersing at least a colorant in a binder resin
to prepare a master batch colorant; kneading toner constituents
comprising at least the master batch colorant and a resin upon
application of heat to prepare a toner constituent mixture, wherein
the resin is the same as or different from the binder resin;
dispersing the toner constituent mixture in an organic solvent
capable of dissolving at least the binder resin and the resin to
prepare an oil phase liquid, wherein the resin is the same as the
binder resin or different from the binder resin; emulsifying the
oil phase liquid in an aqueous liquid to prepare an emulsion;
removing the organic solvent from the emulsion; and drying the
emulsion to prepare the toner particles.
2. The toner composition according to claim 1, wherein the binder
resin comprises a polyester resin.
3. The toner composition according to claim 1, wherein the binder
resin comprises a polyol resin.
4. The toner composition according to claim 1, wherein the binder
resin comprises a styrene-acrylic copolymer.
5. The toner composition according to claim 1, wherein the toner
constituents further comprises a wax.
6. The toner composition according to claim 1, wherein the emulsion
is coagulated by adding a wax emulsion.
7. The toner composition according to claim 1, wherein the emulsion
is coagulated by adding a particulate resin.
8. The toner composition according to claim 1, wherein the colorant
is selected from the group consisting of yellow, magenta, cyan and
black colorants.
9. A method for manufacturing a toner composition comprising toner
particles, comprising: kneading toner constituents comprising at
least a binder resin and a colorant upon application of heat to
prepare a toner constituent mixture; dissolving or swelling the
toner constituent mixture in an organic solvent capable of
dissolving or swelling at least the binder resin to prepare an oil
phase liquid; emulsifying the oil phase liquid in an aqueous liquid
to prepare an emulsion; coagulating the emulsion; and drying the
coagulated emulsion to prepare the toner particles.
10. The method according to claim 9, further comprising: removing
the organic solvent from the emulsion before the coagulation
step.
11. The method according to claim 9, further comprising: removing
the organic solvent from the emulsion after the coagulation
step.
12. The method according to claim 9, wherein the colorant is
selected from the group consisting of yellow, magenta, cyan and
black colorants.
13. A method for manufacturing a toner composition comprising toner
particles, comprising: kneading at least a colorant and a binder
resin to prepare a master batch colorant; dispersing or swelling
toner constituents comprising at least the master batch colorant
and a resin in an organic solvent capable of dissolving or swelling
at least the binder resin and the resin to prepare an oil phase
liquid, wherein the resin is the same as the binder resin or
different from the binder resin; emulsifying the oil phase liquid
in an aqueous liquid to prepare an emulsion; coagulating the
emulsion; and drying the coagulated emulsion to prepare the toner
particles.
14. The method according to claim 13, further comprising: removing
the organic solvent from the emulsion before the coagulation
step.
15. The method according to claim 13, further comprising: removing
the organic solvent from the emulsion after the coagulation
step.
16. The method according to claim 13, wherein the colorant is
selected from the group consisting of yellow, magenta, cyan and
black colorants.
17. A method for manufacturing a toner composition comprising toner
particles, comprising: dispersing at least a colorant in a binder
resin to prepare a master batch colorant; kneading toner
constituents comprising at least the master batch colorant and a
resin upon application of heat to prepare a toner constituent
mixture, wherein the resin is the same as or different from the
binder resin; dispersing the toner constituent mixture in an
organic solvent capable of dissolving at least the binder resin and
the resin to prepare an oil phase liquid, wherein the resin is the
same as the binder resin or different from the binder resin;
emulsifying the oil phase liquid in an aqueous liquid to prepare an
emulsion; removing the organic solvent from the emulsion; and
drying the emulsion to prepare the toner particles.
18. The method according to claim 17, further comprising: removing
the organic solvent from the emulsion before the coagulation
step.
19. The method according to claim 17, further comprising: removing
the organic solvent from the emulsion after the coagulation
step.
20. The method according to claim 17, wherein the colorant is
selected from the group consisting of yellow, magenta, cyan and
black colorants.
21. An image forming apparatus comprising: an image bearer
comprising at least one image bearing member configured to bear an
electrostatic latent image; an image developer comprising at least
one developing section containing a developer including a toner,
wherein the at least one developing section is configured to
develop the electrostatic latent image with the developer to form a
toner image on the image bearing member; and an image transfer
device configured to transfer the toner image onto a receiving
material, wherein the toner is the toner composition according to
claim 1.
22. The image forming apparatus according to claim 21, wherein the
image bearing member bears plural electrostatic latent images,
wherein the image developer comprises plural developing sections
each containing a different color developer including a different
color toner, and develops the plural electrostatic latent images to
form plural color toner images on the image bearing member, and
wherein the image transfer device transfers the plural toner images
onto a receiving material one by one to form a color image.
23. The image forming apparatus according to claim 21, wherein the
image bearer comprises plural image bearing members each bearing an
electrostatic latent image, wherein the image developer comprises
plural developing sections each containing a different color
developer including a different color toner, and develops the
plural electrostatic latent images to form plural color toner
images on the plural image bearing members, and wherein the image
transfer device transfers the plural toner images onto a receiving
material one by one to form a color image.
24. The image forming apparatus according to claim 23, wherein the
image transfer device transfers the plural toner images on an
intermediate transfer medium one by one to form a color image, and
wherein the color image is transferred onto the receiving
material.
25. The image forming apparatus according to claim 22, wherein the
image transfer device transfers the plural toner images on an
intermediate transfer medium one by one to form a color image, and
wherein the color image is transferred onto the receiving
material.
26. The image forming apparatus according to claim 21, wherein the
developer is a two component developer including a carrier and the
toner.
27. The image forming apparatus according to claim 21, wherein the
developer is a one component developer, wherein the at least one
developing section further comprises a developing roller and a
developing blade configured to form a layer of the one component
developer on a surface of the developing roller, and wherein the
developing roller is configured to develop the electrostatic latent
image with the layer of the one component developer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a toner composition for use
in a developer developing an electrostatic latent image formed by
electrophotography, electrostatic recording, electrostatic
printing, etc., and to a method for manufacturing the toner
composition. More particularly, the present invention relates to a
toner composition for use in copiers, laser printers, plain paper
facsimile machines, etc., and to a method for manufacturing the
toner. In addition, the present invention also relates to a color
toner composition for use in full color copiers, full color laser
printers, full color facsimile machines, which use a direct or
indirect electrophotographic developing method, and to a method for
manufacturing the color toner composition.
[0003] 2. Discussion of the Background
[0004] An electrostatic latent image formed on an image bearing
member, for example, by electrophotography, electrostatic
recording, electroprinting or the like method is developed with a
developer to form a visible image (i.e., a toner image) on the
image bearing member (developing process). The toner image is then
transferred onto a receiving material such as receiving paper
optionally via an intermediate transfer medium (transfer process).
The toner image on a receiving material is then fixed on the
receiving material (fixing process).
[0005] As the developer, two-component developers consisting of a
carrier and a toner and one-component developers which do not
include a carrier and which consists of a magnetic or non-magnetic
toner are well known. In a two-component developer, the toner is
frictionally charged, for example, by contacting the carrier. In a
one-component developer, the toner is frictionally charged by
contacting a roller supplying the toner to a developing sleeve, a
blade regulating the toner to form a toner layer on the developing
sleeve and/or the like member.
[0006] In order to prepare high quality images, it has been tried
that toners having a small particle diameter and/or a narrow
particle diameter distribution are used. When such toners are
prepared by a manufacturing method using kneading and pulverizing,
the particles of the resultant toners have an irregular form. When
such an irregular-form toner is used in image forming apparatus,
the toner is further pulverized by being agitated together with a
carrier, and by contacting a developing roller, toner supplying
roller, a toner regulating blade, and a friction-charge applying
blade, resulting in formation of toner particles having a very
small particle diameter. In addition, a fluidizing agent adhering
on the surface of toner particles tends to be embedded into the
toner particles, resulting in deterioration of image qualities.
Further, since toners having an irregular form have poor fluidity,
a large amount of a fluidizing agent has to be added to the toners
and thereby image qualities such as background density and fixing
property of the resultant toner images are deteriorated and in
addition a problem occurs in that the manufacturing costs increase.
In addition, when a toner has poor fluidity, the filling factor of
the toner deteriorates and thereby a toner bottle in which the
toner is filled has to be enlarged in size. Such toners prevent
miniaturization of image forming apparatus.
[0007] In addition, in full color image forming apparatus, color
image transfer processes in which color toner images are
transferred onto receiving materials become complex more and more.
When toners having an irregular form are used for such full color
image forming apparatus, the resultant color images tend to have
omissions because the toners have poor transferability. When it is
attempted to prevent such image omissions, another problem such
that the toner consumption increases tends to occur.
[0008] Therefore a need increases for a toner which has so good
transferability that high quality images can be formed even when a
small amount of the toner is used (i.e., high quality images can be
formed at a low running cost). If a toner having good
transferability is used, a cleaning unit which is used to remove
the toner remaining on the surface of a photoreceptor and an
intermediate transfer medium is unnecessary, and therefore the
image forming apparatus can be miniaturized and the manufacturing
cost thereof can be decreased. In addition, the image forming
apparatus has an advantage in that waste toners are not produced.
However, in reality it is difficult to perfectly transfer toner
images from a photoreceptor or an intermediate transfer medium to a
receiving material. Therefore, in reality, toner particles
remaining on a photoreceptor or an intermediate transfer medium are
removed using a cleaner and the collected toner is reused.
[0009] When a spherical toner is used, it is very difficult to
remove toner particles remaining on a photoreceptor by a cleaner.
Therefore in attempting to provide a toner having a combination of
good properties of the toners having an irregular form and good
properties of the toners having a spherical form, toners having a
slightly deformed spherical form and methods for manufacturing such
toners have been proposed.
[0010] On the other hand, toner manufacturing methods in which fine
toner particles having an irregular form are aggregated to form
aggregated toner particles and then the aggregated toner particles
are fused to unite the fine toner particles. When the fine
particles are prepared by an emulsion polymerization method, resins
including units obtained from one or more radically polymerizable
monomers such as styrene, acrylic and methacrylic monomers have to
be used. However, in view of transparency, flexibility, adhesion to
receiving materials, and plasticizer resistance of toner images, it
is preferable to use polyester resins and polyol resins as the
toner resin. In particular, it is required for full color toners to
have good transparency and sharply-melting property. Therefore
resin particles obtained by an emulsion polymerization method
cannot be used for full color toners.
[0011] Japanese Laid-Open Patent Publications Nos. 10-20552 and
11-7156 (hereinafter referred to as JOPs) have disclosed a toner
manufacturing method in which a polyester resin solution including
a colorant is emulsified in an aqueous liquid and then the
particles of the emulsion are coagulated such that the aggregated
particles have a toner particle size, and a method in which a fine
dispersion of a polyester solution and a fine colorant dispersion
are hetero-aggregated.
[0012] In general, it is difficult to finely disperse dyes and
pigments, which are typically used as colorants, in a solvent which
does not dissolve the dyes and pigments. Therefore the resultant
toners have poor tinting power. In addition, when hetero
aggregation is performed, fine colorant particles in the dispersion
do not necessarily aggregate uniformly together with fine resin
particles in the dispersion, and it is possible that fine colorant
particles aggregate by themselves. Therefore, toners having good
tinting power cannot be provided. In addition, when a colorant
dispersion is prepared, a large amount of a dispersant is needed
and therefore the resultant toner has poor moisture resistance.
Further investigation of controlling the dispersion of a charge
controlling agent and/or release agent included in a toner has not
been performed.
[0013] JOP2-153361 discloses a toner manufacturing method which
includes the steps of melting and kneading toner constituents,
dissolving (or dispersing) the kneaded mixture in a solvent, and
then dispersing the solution (or dispersion) in an aqueous liquid.
By using this method, spherical toner particles can be easily
manufactured. A colorant such as carbon black can be easily
dispersed in a resin by kneading the colorant and the resin upon
application of relatively low shear stress. However, when the
kneaded mixture is dissolved or dispersed in a solvent, the
colorant tends to aggregate again. In addition, it is difficult to
disperse organic pigments in a resin when low shear stress is
applied. Therefore the resultant color toners have poor coloring
property and color reproducibility.
[0014] JOP 7-333890 discloses a toner manufacturing method which
includes the steps of preparing a master batch colorant by kneading
toner constituents, which includes a colorant but not including a
binder resin, and a resin which can be mixed with the binder resin
upon application of high shear stress; dissolving or dispersing the
master batch colorant and a binder resin in an organic solvent; and
then dispersing the solution (or dispersion) in an aqueous liquid.
However, when the master batch colorant and the binder resin are
dissolved or dispersed in an organic solvent, the colorant
aggregates therein. Therefore the resultant color toners have poor
coloring property and color reproducibility. In addition, other
toner constituents such as charge controlling agents and release
agents are excessively dispersed in the master batch colorant, and
therefore the resultant toner has poor charge property and release
property.
[0015] Because of these reasons, a need exists for a toner which
has good coloring property, color reproducibility, charge
properties and releasability.
SUMMARY OF THE INVENTION
[0016] Accordingly, an object of the present invention is to
provide a toner having good coloring property, color
reproducibility, charge properties and releasability.
[0017] Another object of the present invention is to provide a
method for preparing such a toner.
[0018] Briefly these objects and other objects of the present
invention as hereinafter will become more readily apparent can be
attained by a toner composition including toner particles prepared
by a method including the steps of dispersing at least a colorant
in a resin to prepare a master batch colorant; kneading the master
batch colorant and a binder resin, which may be the same as or
different from the resin in the master batch colorant, optionally
together with a release agent, a charge controlling agent, etc.
upon application of heat; dissolving or dispersing the kneaded
mixture in an organic solvent which can dissolve the resin and the
binder resin to prepare an oil phase liquid; dispersing the oil
phase liquid in an aqueous liquid to prepare an emulsion;
coagulating the emulsion before or after optionally removing the
organic solvent; and drying the coagulated emulsion, to prepare the
toner particles.
[0019] The binder resin preferably includes at least one of
polyester resins and polyol resins. The master batch colorant
preferably includes a wax.
[0020] Alternatively, the toner composition can be prepared by a
method including the steps of kneading at least a colorant and a
binder resin upon application of heat; dissolving (or swelling) the
kneaded mixture in an organic solvent to prepare an oil phase
liquid; dispersing the oil phase liquid in an aqueous liquid to
prepare an emulsion; adding a wax dispersion or a resin dispersion
to the emulsion to aggregate the particles of the emulsion.
[0021] By using a yellow colorant, a magenta colorant, a cyan
colorant or a black colorant as the colorant, full color toners can
be provided.
[0022] In another aspect of the present invention, a method for
manufacturing a toner composition including toner particles, is
provided which includes the steps of dispersing at least a colorant
in a resin to prepare a master batch colorant; kneading the master
batch colorant and a binder resin, which may be the same as or
different from the resin in the master batch colorant, optionally
together with a release agent, a charge controlling agent, etc.
upon application of heat; dissolving and/or dispersing the kneaded
mixture in an organic solvent which can dissolve the resin and the
binder resin to prepare an oil phase liquid; dispersing the oil
phase liquid in an aqueous liquid to prepare an emulsion; removing
the organic solvent to prepare toner particle dispersion; and
removing the aqueous liquid to prepare toner particles.
[0023] Alternatively, it is possible to use a method including the
steps of kneading at least a colorant and a binder resin upon
application of heat; dissolving (or swelling) the kneaded mixture
in an organic solvent to prepare an oil phase liquid; dispersing
the oil phase liquid in an aqueous liquid to prepare an emulsion;
removing the organic solvent from the emulsion; and optionally
aggregating the emulsion, to prepare the toner particles.
[0024] By using a yellow colorant, a magenta colorant, a cyan
colorant and a black colorant as the colorant, full color toners
can be provided.
[0025] In yet another aspect of the present invention, an image
forming apparatus is provided which includes an image bearer
including at least one image bearing member configured to bear an
electrostatic latent image; an image developer containing at least
one developing section including a developer including a toner,
wherein the developing section is configured to develop the
electrostatic latent image with the developer to form a toner image
on the image bearing member; and an image transfer device
configured to transfer the toner image onto a receiving material,
wherein the toner is the toner composition of the present invention
mentioned above.
[0026] The toner may be a one component developer or a two
component developer which includes a carrier and the toner. When a
one component developer is used, the image developing device
preferably has a developing roller and a developing blade which
forms a toner layer on the developing roller while controlling the
thickness thereof.
[0027] The image developer may include plural developing sections
each including a different color developer to develop plural latent
images formed on the image bearer, resulting in formation of a
multi-color or full color image. The image bearer may include
plural image bearing members each bearing a different color tone
image.
[0028] Plural color toner images formed on an image bearing member
or plural image bearing members may be transferred onto a receiving
material via an intermediate transfer medium.
[0029] These and other objects, features and advantages of the
present invention will become apparent upon consideration of the
following description of the preferred embodiments of the present
invention taken in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
[0030] Various other objects, features and attendant advantages of
the present invention will be more fully appreciated as the same
becomes better understood from the detailed description when
considered in connection with the accompanying drawing in which
like reference characters designate like corresponding parts
throughout and wherein:
[0031] FIGURE is a schematic view illustrating the cross section of
an image forming apparatus including an embodiment of the image
developing device of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] As a result of the present inventors' investigation, it is
found that by kneading toner constituents including at least a
binder resin and a colorant upon application of heat and then
dissolving (or dispersing when the colorant is not dissolved) the
kneaded toner constituents in an organic solvent, the dispersion of
the toner constituents (particularly the colorant) can be improved.
In addition, it is also found that when a toner is prepared by a
following emulsifying process in which the solution (or dispersion)
is emulsified in an aqueous liquid and which is followed by a
coagulation process in which the emulsion is coagulated, the toner
has good properties. Thus the present invention is made.
[0033] When fine particles of a colorant are dispersed in a binder
resin in a kneading process upon application of high shear stress,
the surface of the fine particles of the colorant well adsorb a
high molecular weight material. The high molecular weight material
adsorbed on the fine particles does not release therefrom even if
the binder resin is dissolved in an organic solvent. Therefore the
thus dispersed fine colorant particles have good dispersion
stability. In contrast, when fine colorant particles of a colorant
are dispersed in an organic solvent together with a binder resin
using a dispersing medium (such as balls of ball mills), the
dispersion stability of the fine colorant particles is inferior to
that of the fine colorant particles dispersed by the
first-mentioned method.
[0034] In other words, it is necessary in the present invention
that colorant particles are kneaded together with a binder resin
upon application of a high shear stress to an extent such that the
polymer adsorbed on the surface of the colorant particles remains
thereon even when the kneaded mixture is dissolved in an organic
solvent after the kneading process.
[0035] In addition, the following is discovered. By preparing a
colorant master batch in which a colorant is well dispersed in a
resin and then kneading the colorant master batch and a resin,
which may be the same as or different from the resin in the
colorant master batch, optionally together with a release agent, a
charge controlling agent, etc. upon application of heat, the
resin/colorant ratio increases and thereby the aggregation of the
colorant can be prevented when the kneaded mixture is dissolved in
an organic solvent. When a colorant master batch is directly
dissolved in an organic solvent, the colorant tends to aggregate.
In addition, it is found that when the shear stress applied to the
mixture in the kneading process is relative low compared to the
shear stress applied when the master batch is prepared, the toner
constituents other than the colorant are not excessively dispersed
(i.e., the toner constituents have a proper dispersion diameter).
In particular, when the charge controlling agent included in the
kneaded mixture is excessively dispersed, the charge properties of
the resultant toner deteriorate. In addition, when the release
agent is excessively dispersed, the releasability of the resultant
toner deteriorates.
[0036] When it is desired to use a resin which is different from
the resin included in a colorant master batch or a resin having a
crosslinking component in the toner, the above-mentioned kneading
method is preferably used. For example, when a resin which is
separated from the resin included in the colorant master batch if
the resins are dissolved in an organic solvent is used, this
kneading method is preferably used. Namely, when a first resin is
kneaded with a colorant master batch including a second resin, the
colorant in the colorant master batch adsorbs the first resin, and
thereby aggregation of the colorant can be prevented when the
kneaded mixture is dissolved in an organic solvent after the
kneading process. In addition, an island/sea structure in which the
first resin is present like islands in a sea of the second resin or
vice versa can be formed in the kneading process, and therefore it
is possible to prepare a toner having a combination of the
advantages of the resins.
[0037] Next, constituents of the toner and developer for use in the
present invention and methods for manufacturing the toner and
developer will be explained in detail.
[0038] Specific examples of the resins for use as the binder resin
of the color master batch, the resins added in the kneading process
and the resins which are used by being dissolved in an organic
solvent, include styrene polymers and substituted styrene polymers
such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene;
styrene copolymers such as styrene-p-chlorostyrene copolymers,
styrene-propylene copolymers, styrene-vinyltoluene copolymers,
styrene-vinylnaphthalene copolymers, styrene-methyl acrylate
copolymers, styrene-ethyl acrylate copolymers, styrene-butyl
acrylate copolymers, styrene-octyl acrylate copolymers,
styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate
copolymers, styrene-butyl methacrylate copolymers, styrene-methyl
.alpha.-chloromethacrylate copolymers, styrene-acrylonitrile
copolymers, styrene-vinyl methyl ketone copolymers,
styrene-butadiene copolymers, styrene-isoprene copolymers,
styrene-acrylonitrile-indene copolymers, styrene-maleic acid
copolymers and styrene-maleic acid ester copolymers; and other
resins such as polymethyl methacrylate, polybutyl methacrylate,
polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene,
polyesters, epoxy resins, epoxy polyol resins, polyurethane resins,
polyamide resins, polyvinyl butyral resins, acrylic resins, rosin,
modified rosins, terpene resins, aliphatic or alicyclic hydrocarbon
resins, aromatic petroleum resins, chlorinated paraffin, paraffin
waxes, etc. These resins are used alone or in combination.
[0039] In the toner of the present invention, polyester resins are
preferably used as a binder resin. Specific examples of the
polybasic carboxylic acids useful for preparing polyester resins
for use in the toner of the present invention include aromatic
dicarboxylic acids such as terephthalic acid, isophthalic acid,
orthophthalic acid, 1,5-naphthalenedicarboxylic acid,
2,6-naphthalenedicarboxylic acid, diphenic acid, sulfoterephthalic
acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid,
4-sulfonaphthalene-2,7-dicarboxylic acid, 5-(sulfophenoxy)
isophthalic acid and sulfoterephthalic acid, and their metal salts
or ammonium salts; aromatic oxycarboxylic acids such as
p-oxybenzoic acid and p-(hydroxyethoxy)benzoic acid; aliphatic
dicarboxylic acids such as succinic acid, adipic acid, azelaic
acid, sebacic acid and dodecane dicarboxylic acid; unsaturated
aliphatic dicarboxylic acids such as fumaric acid, maleic acid,
itaconic acid, hexahydrophthalic acid and tetrahydrophthalic acid;
alicyclic dicarboxylic acids, etc. In addition, polybasic
carboxylic acids such as trimellitic acid, trimesic acid and
pyromellitic acid can also be used.
[0040] Specific examples of the polyhydric alcohols useful for
preparing polyester resins for use in the toner of the present
invention include aliphatic alcohols, alicyclic alcohols and
aromatic alcohols. Specific examples of the aliphatic alcohols
include aliphatic diols such as ethylene glycol, propylene glycol,
1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene
glycol, 2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol,
polypropylene glycol and polytetramethylene glycol; triols and
tetraols such as trimethylol ethane, trimethylol propane, glycerin
and pentaerythritol; etc.
[0041] Specific examples of the alicyclic polyhydric alcohols
include 1,4-cyclohexanediol, 1,4-cyclohexane dimethanol,
spiroglycol, hydrogenated bisphenol A, adducts of hydrogenated
bisphenol A with ethylene oxide or propylene oxide, tricyclodecane
diol, tricyclodecane dimethanol, etc.
[0042] Specific examples of the aromatic polyhydric alcohols
include paraxylene glycol, metaxylene glycol, orthoxylene glycol,
1,4-phenylene glycol, adducts of 1,4-phenylene glycol with ethylene
oxide, bisphenol A, adducts of bisphenol A with ethylene oxide,
etc. In addition, lactone type polyester polyols which can be
prepared by a ring opening polymerization can also be used.
[0043] In order to impart environmental stability to a toner
including a polyester resin, an end polar group of the polyester
resin is preferably reacted with a monomer having a single
functional group. Specific examples of such monomers include
monocarboxylic acids such as benzoic acid, chlorobenzoic acid,
bromobenzoic acid, parahydroxybenzoic acid, mono ammonium salts of
sulfobenzoic acid, mono sodium salts of sulfobenzoic acid,
cyclohexylaminocarbonylbenzoic acid, n-dodecylaminocarbonylbenzoic
acid, tert-butylbenzoic acid, naphthalenecarboxylic acid,
4-methylbenzoic acid, salicylic acid, thiosalicylic acid,
phenylacetic acid, acetic acid, propionic acid, butylic acid,
isobutylic acid, octanecaboxylic acid, lauric acid, stearic acid,
and their lower alkyl esters; and mono alcohols such as aliphatic
alcohols, aromatic alcohols and alicyclic alcohols.
[0044] Various kinds of polyol resins can be used in the toner of
the present invention. However, it is preferable to use polyol
resins which are prepared by reacting an epoxy resin; an adduct of
a dihydric phenol with an alkylene oxide or its glycidyl ether; a
compound having one active hydrogen therein which can react with
the epoxy group of the epoxy resin; and a compound having two or
more active hydrogens therein which can react with the epoxy group
of the epoxy resin. In addition, as the epoxy resin, two or more
kinds of bisphenol A-form epoxy resins each having a different
number average molecular weight are preferably used. The thus
prepared polyester resins can impart good gloss, transparency and
offset resistance to the resultant toner.
[0045] Epoxy resins useful for the polyol resin for use in the
toner of the present invention are preferably prepared by reacting
a bisphenol such as bisphenol A and bisphenol F with
epichlorohydrin. In addition, at least two kinds of bisphenol
A-form epoxy resins one of which has a relatively low number
average molecular weight of from 360 to 2000 and the other of which
has a relatively high number average molecular weight of from 3000
to 10000 are preferably used for preparing a polyol resin for use
in the toner of the present invention. The contents of the low
molecular weight epoxy resin and high molecular weight epoxy resin
are preferably from 20 to 50% by weight and from 5 to 40% by
weight, respectively.
[0046] When the content of the low molecular weight epoxy resin is
too high or the molecular weight of the low molecular weight epoxy
resin is too low, the resultant toner has too high gloss and/or
poor preservability. In contrast, when the content of the high
molecular weight epoxy resin is too high or the molecular weight of
the high molecular weight epoxy resin is too high, the resultant
toner has low gloss and/or poor fixability.
[0047] Specific examples of the adducts of a dihydric phenol
compound with an alkylene oxide useful for the polyol resins for
use in the toner of the present invention include reaction products
of ethylene oxide, propylene oxide, butylene oxide or a mixture
thereof with a bisphenol compound such as bisphenol A or bisphenol
F. The reaction products may be further reacted with
epichlorohydrin or .beta.-methylepichlorohydrin to prepare a
glycidyl ether compound thereof.
[0048] In particular, glycidyl ether compounds of adducts of
bisphenol A with an alkylene oxide, which have the following
formula, can be preferably used. 1
[0049] wherein R represents one of the following groups: 2
[0050] and m and n are independently a positive integer, wherein
the total of m and n is from 2 to 6.
[0051] In addition, the content of the units obtained from an
adduct of a dihydric phenol with an alkylene oxide or its glycidyl
ether compound in the polyol resin is preferably from 10 to 40% by
weight. When the content is too low, a problem in that the
resultant copy sheets curl tends to occur. In contrast, when the
content is too high and/or the total of n and m is greater than 7,
problems such that the gloss of toner images excessively increases,
and/or the preservability of the resultant toner deteriorates tend
to occur.
[0052] Specific examples of the compounds having one active
hydrogen in their molecule, which can react with an epoxy group,
and being useful for polyol resins for use in the toner of the
present invention include monohydric phenol compounds such as
phenol, cresol, isopropyl phenol, aminophenol, octyl phenol, nonyl
phenol, dodecyl phenol, and p-cumyl phenol; secondary amines such
as diethyl amine, dipropyl amine, dibutyl amine, N-methyl (or
ethyl) piperazine, and piperidine; and carboxylic acids such as
propionic acid and caproic acid.
[0053] Polyol resins having a main chain which includes an epoxy
resin unit and an alkylene oxide unit can be obtained from various
combinations of raw materials. For example, an epoxy resin having a
glycidyl group on both ends of its molecule; an adduct of a
dihydric phenol with an alkylene oxide having a glycidyl group on
both ends of its molecule; and a third compound such as dihalides,
diisocyanates, diamines, dithiols, polyhydric phenols and
dicarboxylic acids, are reacted. Among the third compounds,
dihydric phenols are preferable because of having good reaction
stability unless they are gelled. In addition, it is preferable to
use a polyhydric phenol or a polybasic carboxylic acid together
with a dihydric phenol. In this case, the addition quantity of such
a polyhydric phenol or polybasic carboxylic acid is preferably not
greater than 15% by weight and more preferably not greater than 10%
by weight based on total weight of the resultant polyol resin.
[0054] Specific examples of the compounds having two or more active
hydrogens in their molecule which can react with an epoxy group
include dihydric phenols, polyhydric phenols and polybasic
carboxylic acids.
[0055] Specific examples of the dihydric phenols include bisphenols
such as bisphenol A and bisphenol F. Specific examples of
polyhydric phenols include onthocresol novolaks, phenol novolaks,
tris(4-hydroxyphenyl)metha- ne and
1-[.alpha.-methyl-.alpha.-(4-hydroxyphenyl)ethyl]benzene. Specific
examples of the polybasic carboxylic acids include malonic acid,
succinic acid, glutaric acid, adipic acid, maleic acid, fumaric
acid, phthalic acid, terephthalic acid, trimellitic acid, and
trimellitic anhydride.
[0056] When these polyester resins and polyol resins are highly
crosslinked, the resultant toner has poor transparency and gloss.
Therefore, it is preferable that the polyester resins and polyol
resins are not crosslinked or slightly crosslinked such that the
resins include components insoluble in tetrahydrofuran in an amount
not greater than 5% by weight.
[0057] Suitable colorants which are used together with a binder
resin in the kneading processor or used in the colorant master
batch include know dyes and pigments. Specific examples of the
colorants include carbon black, Nigrosine dyes, black iron oxide,
Naphthol Yellow S, Hansa Yellow (10G, 5G and G), Cadmium Yellow,
yellow iron oxide, loess, chrome yellow, Titan Yellow, polyazo
yellow, Oil Yellow, Hansa Yellow (GR, A, RN and R), Pigment Yellow
L, Benzidine Yellow (G and GR), Permanent Yellow (NCG), Vulcan Fast
Yellow (5G and R), Tartrazine Lake, Quinoline Yellow Lake,
Anthrazane Yellow BGL, isoindolinone yellow, red iron oxide, red
lead, orange lead, cadmium red, cadmium mercury red, antimony
orange, Permanent Red 4R, Para Red, Fire Red,
p-chloro-o-nitroaniline red, Lithol Fast Scarlet G, Brilliant Fast
Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL
and F4RH), Fast Scarlet VD, Vulcan Fast Rubine B, Brilliant Scarlet
G, Lithol Rubine GX, Permanent Red F5R, Brilliant Carmine 6B,
Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent
Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, BON Maroon Light,
BON Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y,
Alizarine Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red,
Quinacridone Red, Pyrazolone Red, polyazo red, Chrome Vermilion,
Benzidine Orange, perynone orange, Oil Orange, cobalt blue,
cerulean blue, Alkali Blue Lake, Peacock Blue Lake, Victoria Blue
Lake, metal-free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky
Blue, Indanthrene Blue (RS and BC), Indigo, ultramarine, Prussian
blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, cobalt
violet, manganese violet, dioxane violet, Anthraquinone Violet,
Chrome Green, zinc green, chromium oxide, viridian, emerald green,
Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake,
Malachite Green Lake, Phthalocyanine Green, Anthraquinone Green,
titanium oxide, zinc oxide, lithopone and the like. These materials
are used alone or in combination.
[0058] The content of the colorant in the toner is preferably from
1 to 20 parts by weight per 100 parts by weight of the binder resin
included in the toner. The content of the colorant in the master
batch is preferably from 5 to 500 parts by weight per 100 parts by
weight of the binder resin included in the master batch.
[0059] The toner of the present invention includes a charge
controlling agent if desired. Specific examples of the charge
controlling agent include known charge controlling agents such as
Nigrosine dyes, triphenylmethane dyes, metal complex dyes including
chromium, chelate compounds of molybdic acid, Rhodamine dyes,
alkoxyamines, quaternary ammonium salts (including
fluorine-modified quaternary ammonium salts), alkylamides, phosphor
and compounds including phosphor, tungsten and compounds including
tungsten, fluorine-containing activators, metal salts of salicylic
acid, salicylic acid derivatives, etc.
[0060] Specific examples of the marketed products of the charge
controlling agents include BONTRON 03 (Nigrosine dyes), BONTRON
P-51 (quaternary ammonium salt), BONTRON S-34 (metal-containing azo
dye), E-82 (metal complex of oxynaphthoic acid), E-84 (metal
complex of salicylic acid), and E-89 (phenolic condensation
product), which are manufactured by Orient Chemical Industries Co.,
Ltd.; TP-302 and TP-415 (molybdenum complex of quaternary ammonium
salt), which are manufactured by Hodogaya Chemical Co., Ltd.; COPY
CHARGE PSY VP2038 (quaternary ammonium salt), COPY BLUE (triphenyl
methane derivative), COPY CHARGE NEG VP2036 and NX VP434
(quaternary ammonium salt), which are manufactured by Hoechst AG;
LRA-901, and LR-147 (boron complex), which are manufactured by
Japan Carlit Co., Ltd.; copper phthalocyanine, perylene,
quinacridone, azo pigments and polymers having a functional group
such as a sulfonate group, a carboxyl group, a quaternary ammonium
group, etc.
[0061] The content of the charge controlling agent in the toner of
the present invention depends on the species of the binder resins
used, whether or not additives are added to the toner, and the
toner manufacturing method used, and therefore the content is not
particularly limited. However, the content is typically from 0.1 to
10 parts by weight, and preferably from 0.2 to 5 parts by weight,
per 100 parts by weight of the binder resin used. When the content
of the charge controlling agent is too high, the charge quantity of
the resultant toner excessively increases, resulting in increase of
electrostatic attraction between a developing roller and the toner,
and thereby the image density of the toner images is decreased.
[0062] In the present invention, a charge controlling agent is
preferably kneaded with a binder resin while controlling the
particle diameter of the charge controlling agent dispersed in the
binder resin. When the charge controlling agent used has such a
property as to migrate from an oil phase into an aqueous phase when
the kneaded mixture is emulsified or release from the kneaded
mixture, the charge controlling agent may be added to the aqueous
phase. In this case, the charge controlling agent is incorporated
in the toner when the emulsion is aggregated or the resultant toner
particles are dried.
[0063] The toner preferably includes a wax to improve the
releasability thereof. Suitable waxes for use in the toner include
waxes having a melting point of from 40 to 120.degree. C. and
preferably from 50 to 110.degree. C. When the melting point of the
wax included in the toner is too high, the low temperature
fixability of the resultant toner deteriorates. To the contrary,
when the melting point is too low, the offset resistance and
durability of the resultant toner deteriorate.
[0064] The melting point of waxes (i.e., release agents) can be
determined by a method using a differential scanning calorimeter
(i.e., DSC). Namely, a few milligrams of a sample is heated at a
constant heating speed (for example, 10.degree. C./min) to
determine the temperature at which the sample melts (i.e., the
temperature at which a peak due to melting of the sample is
observed).
[0065] Specific examples of the waxes include solid paraffin waxes,
microcrystalline waxes, rice waxes, fatty acid amide waxes, fatty
acid waxes, aliphatic monoketones, fatty acid metal salt waxes,
fatty acid ester waxes, partially-saponified fatty acid ester
waxes, silicone varnishes, higher alcohols, carnauba waxes,
polyolefins such as low molecular weight polyethylene and
polypropylene, and the like waxes. In particular, polyolefins
having a softening point of from 70.degree. C. to 150.degree. C.,
and preferably from 120.degree. C. to 150.degree. C., which is
determined by a ring and ball method, are preferable.
[0066] It is preferable to knead one or more of these charge
controlling agents and release agents together with a colorant and
a binder resin or to knead them together with a colorant master
batch and a resin, upon application of heat. However, the charge
controlling agents and release agents may be added to other toner
constituents when the kneaded mixture of the toner constituents is
dissolved (or dispersed) in an organic solvent. When this method is
adopted, it is preferable to add a fine dispersion of the charge
controlling agent and/or release agent to the organic solvent. In
order to prepare such a dispersion of charge controlling agent
and/or release agent, for example, the following methods can be
used:
[0067] (1) the agents are dissolved in an organic solvent upon
application of heat, and then the solution is cooled to prepare a
fine dispersion of the agents; and
[0068] (2) the agents are mechanically dispersed in an organic
solvent using a dispersion machine such as ball mills or the
like.
[0069] In addition, a wax emulsion which is mentioned below and in
which a wax is emulsified in an aqueous liquid using a surfactant
or dispersant while being heated and agitated may be added in the
coagulation process of the toner constituents together with fine
particles of toner constituents.
[0070] The thus prepared toner particles can be mixed with an
external additive to assist to improve the fluidity, developing
ability and charge property of the toner particles. Suitable
external additives (hereinafter sometimes referred to as
fluidizers) include particulate inorganic materials, which
preferably have an average primary particle diameter of from 5
m.mu. to 2 .mu.m and more preferably from 5 m.mu. to 500 m.mu.. In
addition, the particulate inorganic materials preferably have a
specific surface area of from 20 to 500 m.sup.2/g when measured by
a BET method. The content of such an external additive in the toner
is from 0.01 to 5% by weight, and preferably from 0.01 to 2.0% by
weight, based on total weight of the toner.
[0071] Specific examples of such inorganic materials include
silica, alumina, titanium oxide, barium titanate, magnesium
titanate, calcium titanate, strontium titanate, zinc oxide, tin
oxide, quartz sand, clay, mica, sand-lime, diatom earth, chromium
oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium
oxide, zirconium oxide, barium sulfate, barium carbonate, calcium
carbonate, silicon carbide, silicon nitride, etc.
[0072] Particulate polymers can also be used as the external
additive. Specific examples of the particulate polymers include
polystyrene resins, copolymers of methacrylic esters and/or acrylic
esters, etc., which can be obtained by soap-free emulsion
polymerization, suspension polymerization or dispersion
polymerization; silicone resins, benzoguanamine resins, nylons,
etc., which can be obtained by a polycondensation method; and
thermo-crosslinked resins.
[0073] These fluidizers are preferably subjected to a surface
treatment to be hydrophobized. When a hydrophobized fluidizer is
used, the fluidity and charge property of the resultant toner can
be improved even under high humidity conditions. For example,
silane coupling agents, silylation agents, silane coupling agents
having a fluoralkyl group, organic titanate coupling agents,
aluminum coupling agents, silicone oils, modified silicone oils,
etc. can be used as the surface treating agent (i.e., the
hydrophobizing agent).
[0074] In addition, the toner may include a cleanability improving
agent which can impart good cleaning property to the toner such
that the toner remaining on the surface of an image bearing member
such as a photoreceptor even after a toner image is transferred can
be easily removed. Specific examples of such a cleanability
improving agent include fatty acids and their metal salts such as
stearic acid, zinc stearate and calcium stearate; and particulate
polymers such as polymethyl methacrylate and polystyrene, which are
manufactured by a method such as soap-free emulsion polymerization
methods.
[0075] When particulate resins are used, the particulate resins
preferably have a relatively narrow particle diameter distribution
and a volume average particle diameter of from 0.01 .mu.m to 1
.mu.m.
[0076] Method for Manufacturing Toner
[0077] Before the kneading operation, toner constituents are
preferably mixed uniformly by a mixer. The mixing method is not
particularly limited. For example, toner constituents including at
least a binder resin and a colorant master batch and optionally a
charge controlling agent and a release agent are mechanically mixed
using a known mixer having a rotating blade.
[0078] After the mixing process, a kneading process is performed in
which the mixture is contained in a kneader and kneaded upon
application of heat thereto.
[0079] Suitable kneaders include kneaders such as single-axis or
double-axis continuous kneaders and batch kneaders such as roll
mills. Specific examples of the kneaders include KTK double-axis
extruders manufactured by Kobe Steel, Ltd., TEM extruders
manufactured by Toshiba Machine Co., Ltd., double-axis extruders
manufactured by KCK Co., Ltd., PCM double-axis extruders
manufactured by Ikegai Corp., and KO-KNEADER manufactured by Buss
AG.
[0080] In the kneading process, it is important to control the
kneading conditions (e.g., kneading temperature) so as not to cut
the molecular chains of the binder resin used in the toner or so as
not excessively disperse the charge controlling agent and release
agent. Specifically, the mixture is kneaded while considering the
softening point of the binder resin used and melting point of the
release agent used. Namely, when kneading is performed at a
temperature much lower than the softening point of the binder resin
used, the molecular chains of the binder resin tend to be cut. When
the kneading temperature is much higher than the softening point,
the charge controlling agent and release agent in the mixture
cannot be fully dispersed.
[0081] When a colorant master batch is used, the colorant master
batch is prepared, for example, by the following method. A resin
and a colorant are mixed and kneaded upon application of high shear
stress. In this case, an organic solvent can be used to encourage
the interaction between the colorant and resin. In addition, a
so-called flashing method in which an aqueous cake of a pigment is
mixed and kneaded with a resin and an organic solvent to transfer
the colorant to the resin phase and then the organic solvent and
water are removed therefrom to prepare a mixture of the colorant
and resin is also preferably used because a wet cake of a colorant
can be used without being dried. When kneading the mixture,
kneaders in which high shear stress can be applied, such as
three-roll mills, can be preferably used.
[0082] Then the kneaded mixture or a combination of the master
batch and a resin, and other toner constituents if necessary, are
dissolved or dispersed in an organic solvent using an impeller,
ball mill, sand mill or homogenizer.
[0083] When kneaded mixture is dissolved or dispersed in an organic
solvent, it is preferable to use organic solvents which are
insoluble, hardly soluble or partially soluble in water and which
can dissolve the resin included in the kneaded mixture. For
example, toluene, xylene, benzene, carbon tetrachloride, methylene
chloride, 1,2-dichloroethane, 1,1,2-trichloroethane,
trichloroethylene, chloroform, monochlorobenzene,
dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl
ketone, methyl isobutyl ketone, etc. can be used. These solvents
can be used alone or in combination. Among these solvents, aromatic
solvents such as toluene and xylene and halogenated hydrocarbons
such as methylene chloride, 1,2-dichloroethane, chloroform and
carbon tetrachloride are preferably used.
[0084] Then the solution or dispersion is emulsified in an aqueous
liquid using an emulsion machine such as HOMOMIXER (manufactured by
Tokushu Kika Kogyo Co., Ltd.), EBARA MILDER (manufactured by Ebara
Corporation), and KUREAMIX (manufactured by M Technique Co., Ltd.).
At this point, by properly controlling the following factors, the
particle size and particle diameter distribution of the oil phase
of the emulsion can be controlled:
[0085] (1) concentration of the emulsifier used;
[0086] (2) concentration of the kneaded mixture in the organic
solvent;
[0087] (3) the weight ratio of the oil phase (i.e., the kneaded
mixture and organic solvent) to the aqueous phase (i.e., the
aqueous liquid);
[0088] (4) the rotation speed of the agitator of the emulsion
machine used;
[0089] (5) the time of the emulsifying treatment; and etc.
[0090] The particle size of the oil phase of the emulsion is
preferably controlled so as to be from 1/2 to 1/100 of the desired
toner particle diameter. The weight ratio of the kneaded mixture to
the organic solvent is preferable 1/10 to 1/1. The weight ratio of
the aqueous phase to the organic phase in the emulsion is
preferably from 10/1 to 1/1.
[0091] Suitable materials for use in the aqueous liquid include
water and organic solvents, which are partially soluble in water,
such as alcohols (e.g., methanol and ethanol), ketones (e.g.,
acetone and methyl ethyl ketone) and esters (e.g., ethyl acetate).
Such organic solvents are used together with water.
[0092] A dispersant can be preferably used to emulsify an oil phase
in which toner constituents are dispersed in an aqueous liquid
including water such that the oil phase has a desired particle
diameter.
[0093] Specific examples of the dispersants include anionic
surfactants such as alkylbenzene sulfonic acid salts,
.alpha.-olefin sulfonic acid salts, and phosphoric acid salts;
cationic surfactants such as amine salts (e.g., alkyl amine salts,
aminoalcohol fatty acid derivatives, polyamine fatty acid
derivatives and imidazoline), and quaternary ammonium salts (e.g.,
alkyltrimethyl ammonium salts, dialkyldimethyl ammonium salts,
alkyldimethyl benzyl ammonium salts, pyridinium salts, alkyl
isoquinolinium salts and benzethonium chloride); nonionic
surfactants such as fatty acid amide derivatives, polyhydric
alcohol derivatives; and ampholytic surfactants such as alanine,
dodecyldi(aminoethyl)glycin, di) octylaminoethyle) glycin, and
N-alkyl-N,N-dimethylammonium betaine.
[0094] By using a surfactant having a fluoroalkyl group, a
dispersion having good dispersibility can be prepared even when a
small amount of the surfactant is used. Specific examples of
anionic surfactants having a fluoroalkyl group include fluoroalkyl
carboxylic acids having from 2 to 10 carbon atoms and their metal
salts, disodium perfluorooctanesulfonylgl- utamate, sodium
3-{omega-fluoroalkyl(C6-C11)oxy}-1-alkyl(C3-C4) sulfonate, sodium
3-{omega-fluoroalkanoyl(C6-C8)-N-ethylamino}-1-propanesulfonate,
fluoroalkyl(C11-C20) carboxylic acids and their metal salts,
perfluoroalkylcarboxylic acids and their metal salts,
perfluoroalkyl(C4-C12)sulfonate and their metal salts,
perfluorooctanesulfonic acid diethanol amides,
N-propyl-N-(2-hydroxyethyl- )perfluorooctanesulfone amide,
perfluoroalkyl(C6-C10)sulfoneamidepropyltri- methylammonium salts,
salts of perfluoroalkyl (C6-C10) -N-ethylsulfonyl glycin,
monoperfluoroalkyl(C6-C16)ethylphosphates, etc.
[0095] Specific examples of the marketed products of such
surfactants include SURFLON S-111, S-112 and S-113, which are
manufactured by Asahi Glass Co., Ltd.; FRORARD FC-93, FC-95, FC-98
and FC-129, which are manufactured by Sumitomo 3M Ltd.; UNIDYNE
DS-101 and DS-102, which are manufactured by Daikin Industries,
Ltd.; MEGAFACE F-110, F-120, F-113, F-191, F-812 and F-833 which
are manufactured by Dainippon Ink and Chemicals, Inc.; ECTOP
EF-102, 103, 104, 105, 112, 123A, 306A, 501, 201 and 204, which are
manufactured by Tohchem Products Co., Ltd.; FUTARGENT F-100 and
F150 manufactured by Neos; etc.
[0096] Specific examples of the cationic surfactants, which can
disperse an oil phase including toner constituents in water,
include primary, secondary and tertiary aliphatic amines having a
fluoroalkyl group, aliphatic quaternary ammonium salts such as
perfluoroalkyl(C6-C10)sulfone- amidepropyltrimethylammonium salts,
benzalkonium salts, benzetonium chloride, pyridinium salts,
imidazolinium salts, etc. Specific examples of the marketed
products thereof include SURFLON S-121 (from Asahi Glass Co.,
Ltd.); FRORARD FC-135 (from Sumitomo 3M Ltd.); UNIDYNE DS-202 (from
Daikin Industries, Ltd.); MEGAFACE F-150 and F-824 (from Dainippon
Ink and Chemicals, Inc.); ECTOP EF-132 (from Tohchem Products Co.,
Ltd.); FUTARGENT F-300 (from Neos); etc.
[0097] In addition, inorganic dispersants, which are hardly soluble
in water, such as tricalcium phosphate, calcium carbonate, titanium
oxide, colloidal silica, and hydroxyapatite can also be used.
[0098] Further, it is possible to stably disperse toner
constituents in an aqueous liquid using a polymeric protection
colloid. Specific examples of such protection colloids include
polymers and copolymers prepared using monomers such as acids
(e.g., acrylic acid, methacrylic acid, .alpha.-cyanoacrylic acid,
.alpha.-cyanomethacrylic acid, itaconic acid, crotonic acid,
fumaric acid, maleic acid and maleic anhydride), acrylic monomers
having a hydroxyl group (e.g., .beta.-hydroxyethyl acrylate,
.beta.-hydroxyethyl methacrylate, .beta.-hydroxypropyl acrylate,
.beta.-hydroxypropyl methacrylate, .gamma.-hydroxypropyl acrylate,
.gamma.-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl
acrylate, 3-chloro-2-hydroxypropyl methacrylate,
diethyleneglycolmonoacrylic acid esters,
diethyleneglycolmonomethacrylic acid esters, glycerinmonoacrylic
acid esters, N-methylolacrylamide and N-methylolmethacrylamide),
vinyl alcohol and its ethers (e.g., vinyl methyl ether, vinyl ethyl
ether and vinyl propyl ether), esters of vinyl alcohol with a
compound having a carboxyl group (i.e., vinyl acetate, vinyl
propionate and vinyl butyrate); acrylic amides (e.g., acrylamide,
methacrylamide and diacetoneacrylamide) and their methylol
compounds, acid chlorides (e.g., acrylic acid chloride and
methacrylic acid chloride), and monomers having a nitrogen atom or
an alicyclic ring having a nitrogen atom (e.g., vinyl pyridine,
vinyl pyrrolidone, vinyl imidazole and ethylene imine).
[0099] In addition, polymers such as polyoxyethylene compounds
(e.g., polyoxyethylene, polyoxypropylene, polyoxyethylenealkyl
amines, polyoxypropylenealkyl amines, polyoxyethylenealkyl amides,
polyoxypropylenealkyl amides, polyoxyethylene nonylphenyl ethers,
polyoxyethylene laurylphenyl ethers, polyoxyethylene stearylphenyl
esters, and polyoxyethylene nonylphenyl esters); and cellulose
compounds such as methyl cellulose, hydroxyethyl cellulose and
hydroxypropyl cellulose, can also be used as the polymeric
protective colloid.
[0100] When the organic solvent is removed from the thus prepared
emulsion, the emulsion is gradually heated to perfectly evaporate
the organic solvent in the oil phase drops, preferably under a
reduced pressure. When this organic solvent removing operation is
performed under a reduced pressure, the operation can be performed
at a relatively low temperature, resulting in prevention of
dissolution of the toner constituents such as waxes into the
organic solvent and abnormal aggregation of the materials dispersed
in the emulsion. This organic solvent removing operation can be
performed before or after the coagulation process which is
mentioned below. When the organic solvent removing operation is
performed before the coagulation process, aggregation of fine
particles of the toner constituents can be accelerated.
[0101] Alternatively, the emulsion may be subjected to a spraying
process. Specifically, the emulsion is sprayed in a dry environment
to evaporate the organic solvent in the oil phase drops, resulting
in formation of fine toner particles. In this case, the aqueous
liquid can also be evaporated. Specific examples of the dry
environment include heated gas such as air, nitrogen, carbon
dioxide and combustion gases. The temperature of the heated gas is
preferably not lower than the highest boiling point of the solvents
included in the emulsion. Specific examples of such dryers include
spray dryers, belt dryers, rotary kilns, etc.
[0102] Then coagulation method of the emulsion will be explained.
For example, the following methods can be used as the coagulation
method:
[0103] (1) an electrolyte is added to the emulsion to thin the
electric double layer, resulting in aggregation of fine
particles;
[0104] (2) a high-molecular-weight water-soluble polymer is added
to be adhered on the fine particles, resulting in aggregation of
the fine particles;
[0105] (3) a material having a charge with a polarity opposite to
that of the surfactant or dispersant included in the emulsion is
added to the emulsion to neutralize the charge on the surface of
the fine particles, resulting in aggregation of the fine
particles;
[0106] (4) a material is added to the emulsion to change the
counter ion of the surfactant or dispersant adhered on the fine
particles, resulting in deterioration of the dispersion stability
of the fine particles, and thereby the fine particles are
aggregated; and
[0107] (5) a material is added to the aqueous phase to change the
solubility of the surfactant or dispersant included in the aqueous
phase, resulting in deterioration of the dispersion stability of
the fine particles, and thereby the fine particles are
aggregated.
[0108] At this point, as mentioned above, a wax emulsion and a
particulate resin having a polar group can be added to aggregate
the fine particles and to impart good releasability and friction
charge properties to the resultant toner particles. When a
particulate resin having a relatively high glass transition
temperature is added, high temperature preservability of the
resultant toner can be improved because a blocking problem in that
toner particles are adhered to each other can be avoided.
[0109] Specific examples of the materials (coagulants) coagulating
the emulsion include electrolytes such as inorganic or organic
water-soluble salts (e.g., sodium sulfate, ammonium sulfate,
potassium sulfate, magnesium sulfate, sodium phosphate, sodium
dihydrogen phosphate, disodium hydrogen phosphate, calcium
chloride, cobalt chloride, strontium chloride, cesium chloride,
barium chloride, nickel chloride, magnesium chloride, rubidium
chloride, sodium chloride, potassium chloride, sodium acetate,
ammonium acetate, potassium acetate and sodium benzoate).
[0110] The addition quantity of the electrolytes is preferably from
0.01 to 2.0 mol/l, more preferably from 0.1 to 1.0 mol/l and even
more preferably from 0.2 to 0.8 mol/l when monovalence electrolyte
is used. When a polyvalence electrolyte is used, the addition
amount can be decreased compared to the case in which a monovalence
electrolyte is used.
[0111] When a surfactant is used as a coagulant, the surfactants
mentioned above can be used. When a polymer coagulant is used, the
polymers mention above for use as the polymeric protective colloid
can be used. In this case, polymers having a very high molecular
weight can be preferably used.
[0112] When a coagulant which is added to the aqueous phase of an
emulsion to depress the dispersion stability of the emulsion is
used, water-soluble organic compounds such as ethanol, butanol,
isopropanol, ethyl cellosolve, butyl cellosolve, dioxane,
tetrahydrofuran, aceton and methyl ethyl ketone can be used.
[0113] In addition, by heating the coagulated emulsion, fine
particles can be fusion-bonded with each other. The aggregated fine
particles are sphered due to surface tension thereof, but by
controlling the heating temperature (while considering the
viscosity of the toner) and the amount of the organic solvent, the
size and shape (from spherical shape to irregular shape) of the
aggregated toner particles can be controlled.
[0114] The thus prepared aggregated emulsion (dispersion) is
sprayed in a dry environment to perfectly dry the organic solvent
to prepare toner particles. At this point, the aqueous liquid can
also be evaporated. Specific examples of the dry environment
include heated gas such as air, nitrogen, carbon dioxide and
combustion gases. The temperature of the heated gas is preferably
not lower than the highest boiling point of the solvents included
in the emulsion. Specific examples of such dryers include spray
dryers, belt dryers, rotary kilns, etc. Before the drying
operation, the coagulated emulsion (dispersion) may be subjected to
a solid-liquid separation treatment followed by a washing treatment
in which the solid is washed with water. When these operations are
repeated, the dispersant and emulsifier used can be removed.
[0115] When an acid- or alkali-soluble material such as calcium
phosphate is used as a dispersion stabilizer, the resultant
particles is preferably subjected to a treatment, in which the
material is dissolved by an acid such as hydrochloric acid, and a
washing treatment in which the particles are washed with water to
remove such a material from the particles. In addition, such a
material can be removed using an enzyme.
[0116] In general, the thus prepared particles have a narrow
particle diameter distribution, and therefore the particles can be
used as a toner without being subjected to a further treatment.
However, when the thus prepared toner particles have a wide
particle diameter distribution even after the particles are
subjected to a washing treatment followed by a drying treatment,
the toner particles are preferably subjected to a classification
treatment using a cyclone, a decanter or a method utilizing
centrifuge such that the toner particles have a desired particle
diameter distribution. However, it is preferable to perform the
classification operation in a liquid having the particles in view
of efficiency. The toner particles having an undesired particle
diameter can be reused as the raw materials for the kneading
process. Such toner particles for reuse may be in a dry condition
or a wet condition. At this point, the dispersant used is removed
together with the particles having undesired fine particle
diameter.
[0117] The thus prepared toner particles are then mixed with one or
more other particulate materials such as release agents, charge
controlling agents, fluidizers and colorants optionally upon
application of mechanical impact thereto to fix the particulate
materials on the toner particles.
[0118] Specific examples of such mechanical impact application
methods include methods in which a mixture is mixed with a highly
rotated blade and methods in which a mixture is put into a jet air
to collide the particles against each other or a collision
plate.
[0119] Specific examples of such mechanical impact applicators
include ONG MILL (manufactured by Hosokawa Micron Co., Ltd.),
modified I TYPE MILL in which the pressure of air used for
pulverizing is reduced (manufactured by Nippon Pneumatic Mfg. Co.,
Ltd.), HYBRIDIZATION SYSTEM (manufactured by Nara Machine Co.,
Ltd.), KRYPTRON SYSTEM (manufactured by Kawasaki Heavy Industries,
Ltd.), automatic mortars, etc.
[0120] Then the developer of the present invention will be
explained in detail.
[0121] The toner of the present invention can be used for a
two-component developer in which the toner is mixed with a magnetic
carrier. The weight ratio (T/C) of the toner (T) to the carrier (C)
is preferably from 1/100 to 10/100.
[0122] Suitable carriers for use in the two component developer
include known carrier materials such as iron powders, ferrite
powders, magnetite powders, magnetic resin carriers, which have a
particle diameter of from about 20 .mu.m to about 200 .mu.m. The
surface of the carriers may be coated by a resin.
[0123] Specific examples of such resins to be coated on the
carriers include amino resins such as urea-formaldehyde resins,
melamine resins, benzoguanamine resins, urea resins, and polyamide
resins, and epoxy resins. In addition, vinyl or vinylidene resins
such as acrylic resins, polymethylmethacrylate resins,
polyacrylonitirile resins, polyvinyl acetate resins, polyvinyl
alcohol resins, polyvinyl butyral resins, polystyrene resins,
styrene-acrylic copolymers, halogenated olefin resins such as
polyvinyl chloride resins, polyester resins such as
polyethyleneterephthalate resins and polybutyleneterephthalate
resins, polycarbonate resins, polyethylene resins, polyvinyl
fluoride resins, polyvinylidene fluoride resins,
polytrifluoroethylene resins, polyhexafluoropropylene resins,
vinylidenefluoride-acrylate copolymers,
vinylidenefluoride-vinylfluoride copolymers, copolymers of
tetrafluoroethylene, vinylidenefluoride and other monomers
including no fluorine atom, and silicone resins.
[0124] If desired, an electroconductive powder may be included in
the toner. Specific examples of such electroconductive powders
include metal powders, carbon blacks, titanium oxide, tin oxide,
and zinc oxide. The average particle diameter of such
electroconductive powders is preferably not greater than 1 .mu.m.
When the particle diameter is too large, it is hard to control the
resistance of the resultant toner.
[0125] The toner of the present invention can also be used as a
one-component magnetic developer or a one-component non-magnetic
developer, which does not use a carrier.
[0126] Then the electrophotographic image forming method and
apparatus will be explained.
[0127] In the image forming method (apparatus) of the present
invention, a two-component or one-component developer can be used.
The image forming apparatus has an image developer having at least
a developing section including a developing roller having a
magnetic sleeve, a developing roller constituted of an elastic
material or a developing roller made of a metal. In addition, the
developing section includes a regulating blade which regulates the
developer to form a uniform developer layer on the developing
roller. When multi-colororfull color images are formed, an image
developer having plural developing sections each of which has a
color developer having a different color toner is used.
[0128] An electrostatic latent image formed on a photoreceptor
using a charger such as contact changers using an electroconductive
brush or roller and an imagewise light irradiator is developed with
the developer formed on the developing roller to form a toner image
on the photoreceptor. When multi-color or full color images are
formed, plural electrostatic latent images formed on different
areas of the photoreceptor are developed using the plural
developers in the plural developing sections one by one. The thus
formed color toner images are transferred on a receiving material
one by one, resulting in formation of a multi-color image or a full
color image on the receiving material at once.
[0129] In this case, the plural electrostatic latent images may be
formed on plural photoreceptors. In addition, the color toner
images formed on a photoreceptor or plural photoreceptors may be
transferred on an intermediate transfer medium to form a
multi-color toner image or a full color toner image thereon. The
color toner image on the intermediate transfer medium is then
transferred on a receiving material.
[0130] In the developing process, a reverse development method in
which a latent image is developed with a developer having a charge
with the same polarity as that of the latent image is preferably
used. In addition, a developing method in which a latent image is
developed while the developing roller is rotated at a rotation
speed faster than that of the photoreceptor is preferably used. In
this case, the developing roller contacts or does not contact the
photoreceptor.
[0131] In the image forming method (apparatus), known image
transfer devices using a corotron or a transfer member which
presses a receiving material toward the photoreceptor can be
used.
[0132] The image forming apparatus of the present invention will be
explained in detail referring to a drawing.
[0133] FIGURE is a schematic view illustrating a cross section of
an embodiment of the image forming apparatus of the present
invention.
[0134] As shown in FIGURE, in a color image reading unit 1 an image
of an original 3 is focused on a color sensor 7 using a lamp 4,
mirrors 5a, 5b and 5c and lens 6. The image is read by the color
sensor 7 while being separated into, for example, a blue (B) image,
a green (G) image and a red (R) image, and then the B, G and R
images are converted to electric image signals. Then the image
signals are subjected to a color conversion treatment by an image
processor (not shown) to form black (Bk), cyan (C), magenta (M) and
yellow (Y) image data
[0135] According to the thus prepared color (Bk, C, M and Y) image
data, a full color toner image is formed on a receiving material by
the following method. A color image forming unit 2 includes a
photoreceptor 9 which rotates in the counterclockwise direction.
Around the photoreceptor drum 9, a cleaning unit 10 which includes
a pre-cleaning discharger and which cleans the surface of the
photoreceptor drum 9; a discharge lamp 11 which discharges charges
remaining on the photoreceptor drum 9; a charger 12 which charges
the photoreceptor drum 9; a potential sensor 13; a BK image
developer 14; a C image developer 15; an M image developer 16; a Y
image developer 17; a developing density pattern detector 18; an
intermediate transfer medium 19, etc. are arranged.
[0136] Each image developer 14, 15, 16 or 17 includes a developing
sleeve which rotates to carry a developer such that the developer
faces the photoreceptor 9 to develop a latent image on the
photoreceptor 9, a paddle which rotates to scoop up and agitate the
developer, and a toner concentration detecting sensor (14c, 15c,
16c or 17c) which detects the toner concentration in each
developer. Each image developer 14, 15, 16 or 17 contains a
different color developer.
[0137] Then the image forming process will be explained in detail
when Bk, C, M and Y images are formed in this order. The developing
order is not limited thereto.
[0138] When a coping operation is started, the black image data is
sent to the color image forming unit 2. An image writing unit 8
converts the black image data to photo signals. According to the
photo signals, a laser beam irradiates the photoreceptor drum 9 to
form a BK latent image thereon. Nemerals 8a, 8b, 8c, 8d and 8e
denote a laser source, a polygon mirror, a case, a lens and a
mirror. At this point, the potential of an image area of the latent
image is from -80 to -130V and the potential of a non-image area is
from -500 to -700V. The developing sleeve of the Bk image developer
14 starts to rotate before the tip of the Bk latent image reaches
the developing position in the Bk image developer 14 to develop the
Bk latent image with the Bk developer (i.e., the Bk toner). This
developing operation is continued until the rear end of the Bk
latent image passes the developing position. The Bk image developer
14 achieves a dormant state before the C developing operation is
started.
[0139] The BK toner image formed on the photoreceptor 9 is
transferred onto the intermediate transfer belt 19 which is fed at
the same speed as that of the photoreceptor 9. Hereinafter this
toner transfer is sometimes referred to as the belt transfer. The
intermediate transfer belt 19 is supported by a driving roller 21,
a transfer bias roller 20a, a ground roller 20b and driven rollers
while being tensed.
[0140] The intermediate transfer belt 19 is typically made of a
fluorine-containing resin such as ETFE
(ethylene-tetrafluoroethylene copolymer), in which carbon black is
dispersed such that the intermediate transfer belt 19 has a volume
resistivity not higher than 10.sup.9 .OMEGA..multidot.cm. Specific
examples of the transfer bias roller 20a include hydrin rubber
rollers which are covered with a PFE tube and have a volume
resistivity not higher than 10.sup.9 .OMEGA..multidot.cm. Specific
examples of the ground roller 20b include rollers whose shafts are
grounded.
[0141] The belt transfer is performed while the photoreceptor 9 is
contacted with the intermediate transfer belt 19 and a
predetermined bias voltage is applied to the transfer bias roller
20a. At this point, the transfer bias roller 20a and ground roller
20b press the intermediate transfer belt 19 to the photoreceptor
9.
[0142] Since the intermediate transfer belt 19 is grounded by the
ground roller 20b, an electric field is formed by the transfer bias
roller 20a in the area at which the intermediate transfer belt 19
contacts the photoreceptor 9. Namely,, the electric field does not
influence on the toner images on the photoreceptor 9 which toner
images do not yet contact the intermediate transfer belt 19.
Therefore problems in that the distance between toner particles of
the toner images widen and voids are formed in the toner images can
be prevented.
[0143] After the Bk toner image has been transferred on the
intermediate transfer belt 19, the photoreceptor 9 is cleaned by
the cleaner 10 and then discharged by the discharge lamp 11. Then
the photoreceptor is charged again by the charger 12 to form a C
latent image.
[0144] Then C image data are sent to the color image forming unit 2
and the image writing unit 8 converts the C image data to photo
signals to irradiate the photoreceptor 9 with imagewise light.
Thus, a C latent image is formed on the photoreceptor 9.
[0145] Similarly to the Bk developing process, the C developing
section 15 develops the C latent image with the C developer to form
a C toner image on the photoreceptor 9. The thus prepared C toner
image is then transferred onto a proper position of the Bk toner
image on the intermediate transfer belt 19.
[0146] The M and Y image developing operations are performed in the
similar way as performed in the Bk and C image developing
operations. Thus a full color toner image is formed on the
intermediate transfer belt 19.
[0147] The full color image on the intermediate transfer belt 19 is
transferred onto a receiving material by the following method. In
FIGURE, a paper transfer unit 23 includes a paper transfer bias
roller, a roller cleaning blade, and a belt touch/detach mechanism.
The bias roller is ordinarily separated from the intermediate
transfer belt 19. When the full color image formed on the
intermediate transfer belt 19 are transferred to a receiving
material, the receiving material is timely pressed by the belt
touch/detach mechanism to transfer the full color image onto the
proper position of the receiving material while a bias voltage is
applied to the receiving material. Thus, the full color toner image
is transferred onto the receiving material.
[0148] As shown in FIGURE, a receiving material 24 is timely fed by
a feed roller 25, and a registration roller 26 such that the four
color images on the intermediate transfer belt 19 can be
transferred onto the proper position of the receiving material
24.
[0149] As shown in FIGURE, a belt cleaning unit 22 includes a brush
roller, a rubber blade, and a belt touch/detach mechanism. When the
Bk, C, M and Y toner images are transferred onto the intermediate
transfer belt 19, the belt cleaning unit 22 are detached from the
intermediate transfer belt 19. After the full color toner image is
transferred onto the receiving material 24, the belt cleaning unit
22 is pressed to the intermediate transfer belt 19 by the belt
touch/detach mechanism to clean the surface of the intermediate
transfer belt 19.
[0150] In FIGURE, the receiving material 24 on which the full color
toner image has been transferred is fed by a paper feeding unit 27
to a fixer 28. In the fixer 28, the full color toner image on the
receiving material 24 is fixed at a nip of a fixing roller 28a
which is controlled so as to have a predetermined temperature, and
a pressure roller 28b.
[0151] In the image forming method (or apparatus), a fixing method
in which heat is applied to the toner image by a roller upon
application of pressure thereto is preferably used. The temperature
of the fixing roller 28a is preferably from 160 to 190.degree. C.,
and more preferably from 170 to 185.degree. C. In addition, it is
preferable to apply a release agent (e.g., silicone oils) on the
fixing roller 28a. When setting of the fixing temperature is too
low, the fixed toner image tends to have voids because the toner
particles are not fully melted. In contrast, when setting of the
fixing temperature is too high, heat cannot be fully applied to the
fixing roller 28a when copies are continuously produced.
[0152] The receiving material 24 having the full color image is
then fed to a copy tray 29.
[0153] As shown in FIGURE, various sizes of papers are set in paper
cassettes 30, 31, 32 and 33. The paper specified by the operation
panel (not shown) is fed toward the registration roller 26 from its
cassette. Numeral 34 denotes a manual paper feed tray from which an
OHP film, a thick paper or the like receiving sheet is manually
fed.
[0154] The method in which a full color image is formed of four
color images (i.e., black, cyan, magenta and yellow images) has
been explained. However, if desired, three color images or two
color images can be also produced in the same method as mentioned
above except that three or two of the image forming operations are
performed. When monocolor images are produced, only one of the
image developer 14, 15, 16 and 17 achieves an active state (i.e.,
the ear of the developer is erected) until the copies are
completed. The intermediate transfer belt 19 can be forwarded while
contacting the surface of the photoreceptor 19. In addition, the
copy operation can be performed while the belt cleaner 22 contacts
the intermediate transfer belt 19.
[0155] Having generally described this invention, further
understanding can be obtained by reference to certain specific
examples which are provided herein for the purpose of illustration
only and are not intended to be limiting. In the descriptions in
the following examples, the numbers represent weight ratios in
parts, unless otherwise specified.
EXAMPLES
Toner Manufacturing Example 1
[0156] Preparation of Black Toner
[0157] The following components were mixed using a mixer.
1 Styrene-n-butyl acrylate copolymer 100 (St/nBA of 80:20 by
weight, Mn of 23000, Mw/Mn of 5.6 and Tg of 65.degree. C.) Carbon
black 4.5 (MA60 from Mitsubishi Chemical Corp.) Pigment Blue 15:3
0.5 Charge controlling agent 2 (BONTRON E-84 from Orient Chemical
Co., Ltd.)
[0158] The mixture was kneaded using a two-roll mill upon
application of heat. The kneaded mixture was subjected to roll
cooling. The kneaded mixture was dissolved in 200 parts of toluene
contained in a tank while agitating with an agitator. Thus a resin
solution (or a pigment dispersion) to serve as an oil phase was
prepared (hereinafter referred to as an oil phase liquid).
[0159] On the other hand, the following components were mixed to
prepare an aqueous liquid (i.e., an aqueous phase liquid or a
continuous phase liquid).
2 Deionized water 700 Sodium dodecylbenzenesulfonate 1
[0160] The oil phase liquid was added to the aqueous phase liquid
while the mixture was agitated with a mixer, HOMOMIXER manufactured
by Tokushu Kika Kogyo Co., Ltd. At this point, the rotation speed
of the rotor of the mixer was controlled such that the oil phase
had a volume average particle diameter of about 1 .mu.m.
[0161] Then the mixture was heated to 50.degree. C. under a reduced
pressure to remove toluene therefrom. Thus, an emulsion having a
dark gray color was prepared. The emulsion was contained in a tank
having an impeller and a solution of 10 parts of aluminum sulfate
and 90 parts of deionized water was added thereto while the mixture
was agitated at a low rotation speed to coagulate the emulsion
(i.e., to aggregate the particles). The mixture was heated to
70.degree. C. and the temperature was maintained. The heated
mixture was observed using a scanning electron micrometer that the
aggregated particles therein were fused and united. Then the
mixture was repeatedly subjected to a filtering treatment followed
by a washing treatment to prepare a wet cake. Then the wet cake was
dried under a reduced pressure. Thus black particles were
prepared.
[0162] Then 100 parts of the black particles were mixed with 0.5
parts of a hydrophobized silica R972 having a primary particle
diameter of 16 nm and manufactured by Nippon Aerosil Co., using a
Henshel mixer. The mixture was sieved using a mesh having openings
of 50 .mu.m to remove coarse particles.
[0163] Thus, a black toner T1-K was prepared.
[0164] Preparation of Yellow, Magenta and Cyan Toners
[0165] The procedure for preparation of the black toner T1-K was
repeated except that the colorant (i.e., carbon black and Pigment
Blue 15:3) was replaced with 5 parts of Pigment Yellow 17, 5 parts
of Pigment Red 57 or 5 parts of Pigment Blue 15:3.
[0166] Thus, a yellow toner T1-Y, a magenta toner T1-M and a cyan
toner T1-C were prepared.
Toner Manufacturing Example 2
[0167] The procedure for preparation of the black toner T1-K was
repeated except that the formulation of the toner was changed as
follows:
3 Styrene-n-butyl acrylate copolymer 100 (St/nBA of 30:20 by
weight, Mn of 23000, Mw/Mn of 5.6 and Tg of 65.degree. C.) Carbon
black 4.5 (MA60 from Mitsubishi Chemical Corp.) Pigment Blue 15:3
0.5 Charge controlling agent 2 (BONTRON E-84 from Orient Chemical
Industries Co.,Ltd.) Carnauba wax 5
[0168] Thus, a black toner T2-K was prepared.
[0169] Preparation of Yellow, Magenta and Cyan Toners
[0170] The procedure for preparation of the black toner T2-K was
repeated except that the colorant (i.e., carbon black and Pigment
Blue 15:3) was replaced with 5 parts of Pigment Yellow 17, 5 parts
of Pigment Red 57 or 5 parts of Pigment Blue 15:3.
[0171] Thus, a yellow toner T2-Y, a magenta toner T2-M and a cyan
toner T2-C were prepared.
Toner Manufacturing Example 3
[0172] Preparation of Black Toner
[0173] The following components were contained in a beaker, and
mixed using HOMOMIXER.
4 Carnauba wax 40 Deionized water 56 Polyethylene glycol
nonylphenyl ether 4
[0174] The mixture was dispersed by HOMOMIXER while heated to
90.degree. C. to emulsify the wax. Then the wax emulsion was
cooled. When the wax emulsion was observed by a scanning electron
microscope, the average particle diameter of the wax particles was
0.2 .mu.m.
[0175] Then 12.5 parts of the wax emulsion were added to the dark
gray emulsion prepared in Example 1 (to which aluminum sulfate was
not added) to perform a coagulation treatment.
[0176] The mixture was heated to 70.degree. C. and the temperature
was maintained. The heated mixture was observed using a scanning
electron micrometer that the aggregated particles therein were
fused and united. Then the mixture was repeatedly subjected to a
filtering treatment followed by a washing treatment to prepare a
wet cake. Then the wet cake was dried under a reduced pressure.
Thus a black particles were prepared.
[0177] Then 100 parts of the black particles were mixed with 0.5
parts of a hydrophobized silica R972 having a primary particle
diameter of 16 nm and manufactured by Nippon Aerosil Co., using a
Henshel mixer. The mixture was sieved using a mesh having openings
of 50 .mu.m to remove coarse particles.
[0178] Thus, a black toner T3-K was prepared.
[0179] Preparation of Yellow, Magenta and Cyan Toners
[0180] The procedure for preparation of the black toner T3-K was
repeated except that the colorant (i.e., carbon black and Pigment
Blue 15:3) was replaced with 5 parts of Pigment Yellow 17, 5 parts
of Pigment Red 57 or 5 parts of Pigment Blue 15:3.
[0181] Thus, a yellow toner T3-Y, a magenta toner T3-M and a cyan
toner T3-C were prepared.
Toner Manufacturing Example 4
[0182] Preparation of Black Toner
[0183] The procedure for preparation of the black toner T2-K in
Toner Manufacturing Example 2 was repeated except that polymethyl
methacrylate particles having an average particle diameter of 0.4
.mu.m (MP1000 from Soken Chemical & Engineering Co., Ltd.) were
added to the dark gray emulsion before aluminum sulfate was added
thereto.
[0184] Thus a black toner T4-K was prepared.
[0185] Preparation of Yellow, Magenta and Cyan Toners
[0186] The procedure for preparation of the black toner T4-K was
repeated except that the colorant (i.e., carbon black and Pigment
Blue 15:3) was replaced with 5 parts of Pigment Yellow 17, 5 parts
of Pigment Red 57 or 5 parts of Pigment Blue 15:3.
[0187] Thus, a yellow toner T4-Y, a magenta toner T4-M and a cyan
toner T4-C were prepared.
Toner Manufacturing Example 5
[0188] Preparation of Black Toner
[0189] The procedure for preparation of the black toner T2-K in
Toner Manufacturing Example 2 was repeated except that the
styrene-n-butyl acrylate copolymer was replaced with 100 parts of a
polyester resin having an acid value of 3, a hydroxyl value of 25,
a weight average molecular weight (Mw) of 45000, a Mw/Mn ratio of
4.0 and a glass transition temperature Tg of 60.degree. C.
[0190] Thus a black toner T5-K was prepared.
[0191] Preparation of Yellow, Magenta and Cyan Toners
[0192] The procedure for preparation of the black toner T5-K was
repeated except that the colorant (i.e., carbon black and Pigment
Blue 15:3) was replaced with 5 parts of Pigment Yellow 17, 5 parts
of Pigment Red 57 or 5 parts of Pigment Blue 15:3.
[0193] Thus, a yellow toner T5-Y, a magenta toner T5-M and a cyan
toner T5-C were prepared.
Toner Manufacturing Example 6
[0194] Preparation of Black Toner
[0195] The procedure for preparation of the black toner T2-K in
Toner Manufacturing Example 2 was repeated except that the
styrene-n-butyl acrylate copolymer was replaced with 100 parts of a
polyol resin which had been prepared by reacting a dihydric phenol
compound with a glycidyl ether compound of an adduct of bisphenol A
with an alkylene oxide and which has a weight average molecular
weight (Mw) of 40000, a Mw/Mn ratio of 5.3 and a glass transition
temperature Tg of 63.degree. C.
[0196] Thus a black toner T6-K was prepared.
[0197] Preparation of Yellow, Magenta and Cyan Toners
[0198] The procedure for preparation of the black toner T6-K was
repeated except that the colorant (i.e., carbon black and Pigment
Blue 15:3) was replaced with 5 parts of Pigment Yellow 17, 5 parts
of Pigment Red 57 or 5 parts of Pigment Blue 15:3.
[0199] Thus, a yellow toner T6-Y, a magenta toner T6-M and a cyan
toner T6-C were prepared.
Toner Manufacturing Example 7 (Comparative Example)
[0200] Preparation of Black Toner
[0201] The procedure for preparation of the black toner T1-K in
Toner Manufacturing Example 1 was repeated except that the toner
constituents were mixed with toluene and the mixture was dispersed
using a ball mill without kneading the toner constituents.
[0202] Thus a black toner T7-K was prepared.
[0203] Preparation of Yellow, Magenta and Cyan Toners
[0204] The procedure for preparation of the black toner T7-K was
repeated except that the colorant (i.e., carbon black and Pigment
Blue 15:3) was replaced with 5 parts of Pigment Yellow 17, 5 parts
of Pigment Red 57 or 5 parts of Pigment Blue 15:3.
[0205] Thus, a yellow toner T7-Y, a magenta toner T7-M and a cyan
toner T7-C were prepared.
Toner Manufacturing Example 8 (Comparative Example)
[0206] Preparation of Black Toner
[0207] The procedure for preparation of the black toner T2-K in
Toner Manufacturing Example 2 was repeated except that the toner
constituents were mixed with toluene and heated to 70.degree. C. to
dissolve the resin and wax in toluene without kneading the toner
constituents and then the mixture, which was cooled to precipitate
the wax, was dispersed using a ball mill containing zirconia beads
to prepare an oil phase liquid.
[0208] Thus a black toner T8-K was prepared.
[0209] Preparation of Yellow, Magenta and Cyan Toners
[0210] The procedure for preparation of the black toner T8-K was
repeated except that the colorant (i.e., carbon black and Pigment
Blue 15:3) was replaced with 5 parts of Pigment Yellow 17, 5 parts
of Pigment Red 57 or 5 parts of Pigment Blue 15:3.
[0211] Thus, a yellow toner T8-Y, a magenta toner T8-M and a cyan
toner T8-C were prepared.
Master Batch Colorant Manufacturing Example 1
[0212] Preparation of Black Color Master Batch
[0213] The following components were mixed using a flasher.
5 Water 1200 Phthalocyanine green aqueous cake 200 (solid content
of 30%) Carbon black 540 (MAGO from Mitsubishi Chemical Corp.)
[0214] Then 1,200 parts of a polyester resin having an acid value
of 3, a hydroxyl value of 25, a weight average molecular weight Mw
of 45,000, a Mw/Mn ratio of 4.0, and a glass transition temperature
of 60.degree. C. were added to the mixture, and the mixture was
kneaded by a two-roll mill at 150.degree. C. for 30 minutes. Then
1,000 parts of xylene were added thereto, and the mixture was
further kneaded for 1 hour. After water and xylene were removed
therefrom, the residue was cooled by rolling and then pulverized by
a pulverizer. Thus a black color master batch MB1-K was
prepared.
[0215] Preparation of Yellow Color Master Batch
[0216] The following components were mixed using a flasher.
6 Water 600 Pigment yellow aqueous cake 1200 (solid content of
50%)
[0217] Then 1,200 parts of a polyester resin having an acid value
of 3, a hydroxyl value of 25, a weight average molecular weight Mw
of 45,000, a Mw/Mn ratio of 4.0, and a glass transition temperature
of 60.degree. C. were added to the mixture, and the mixture was
kneaded at 150.degree. C. for 30 minutes. Then 1,000 parts of
xylene were added thereto, and the mixture was further kneaded for
1 hour. After water and xylene were removed therefrom, the residue
was cooled by rolling and then pulverized by a pulverizer. In
addition, the pulverized mixture was kneaded by a three-roll mill
twice. Thus a yellow color master batch MB1-Y was prepared.
[0218] Preparation of Magenta Color Master Batch
[0219] The following components were mixed using a flasher.
7 Water 600 Pigment red 57 aqueous cake 1200 (solid content of
50%)
[0220] Then 1,200 parts of a polyester resin having an acid value
of 3, a hydroxyl value of 25, a weight average molecular weight Mw
of 45,000, a Mw/Mn ratio of 4.0, and a glass transition temperature
of 60.degree. C. were added to the mixture, and the mixture was
kneaded at 150.degree. C. for 30 minutes. Then 1,000 parts of
xylene were added thereto, and the mixture was further kneaded for
1 hour. After water and xylene were removed therefrom, the residue
was cooled by rolling and then pulverized by a pulverizer. In
addition, the pulverized mixture was kneaded by a three-roll mill
twice. Thus a yellow color master batch MB1-M was prepared.
[0221] Preparation of Cyan Color Master Batch
[0222] The following components were mixed using a flasher.
8 Water 600 Pigment blue 15:3 aqueous cake 1200 (solid content of
50%)
[0223] Then 1,200 parts of a polyester resin having an acid value
of 3, a hydroxyl value of 25, a weight average molecular weight Mw
of 45,000, a Mw/Mn ratio of 4.0, and a glass transition temperature
of 60.degree. C. were added to the mixture, and the mixture was
kneaded at 150.degree. C. for 30 minutes. Then 1,000 parts of
xylene were added thereto, and the mixture was further kneaded for
1 hour. After water and xylene were removed therefrom, the residue
was cooled by rolling and then pulverized by a pulverizer. In
addition, the pulverized mixture was kneaded by a three-roll mill
twice. Thus a yellow color master batch MB1-C was prepared.
Master Batch Colorant Manufacturing Example 2
[0224] The procedures for preparation of the color master batches
MB1-K, MB1-Y, MB1-M and MB1-C were repeated except that the
following components were added when the pigment aqueous cake was
mixed with water.
9 Carnauba wax 900 Charge controlling agent 300 (BONTRON E-84 from
Orient Chemical Industries Co., Ltd.)
[0225] Thus, a black color master batch MB2-K, a yellow color
master batch MB2-Y, a magenta color master batch MB2-M and a cyan
color master batch MB2-C were prepared.
Toner Manufacturing Example 9
[0226] Preparation of Black Toner
[0227] The following components were mixed and dispersed in a ball
mill containing zirconia beads to prepare an oil phase liquid.
10 Styrene-n-butyl acrylate copolymer 100 (St/nBA = 80:20 by
weight, weight average molecular weight Mw of 23000, Mw/Mn ratio of
5.6 and glass transition temperature of 65.degree. C.) Black color
master batch MB1-K 12 Charge controlling agent 2 (BONTRON E-84 from
Orient Chemical Industries Co., Ltd.) Toluene 200
[0228] On the other hand, the following components were mixed by an
agitator to prepare an aqueous phase liquid.
11 Deionized water 700 Sodium dodecylbenzensulfonate 1
[0229] The above-prepared oil phase was added to the aqueous phase
while the mixture was agitated with a mixer, HOMOMIXER manufactured
by Tokushu Kika Kogyo Co., Ltd. At this point, the rotation speed
of the rotor of the mixer was controlled such that the oil phase
had a volume average particle diameter of about 1 .mu.m.
[0230] Then the mixture was heated to 50.degree. C. under a reduced
pressure to remove toluene therefrom. Thus, an emulsion having a
dark gray color was prepared. The emulsion was contained in a tank
having an impeller and a solution of 10 parts of aluminum sulfate
dissolved in 90 parts of deionized water was added thereto while
the mixture was agitated at a low rotation speed to coagulate the
emulsion (i.e., to aggregate the particles). The mixture was heated
to 70.degree. C. and the temperature was maintained. The heated
mixture was observed using a scanning electron micrometer that the
aggregated particles therein were fused and united. Then the
mixture was repeatedly subjected to a filtering treatment followed
by a washing treatment to prepare a wet cake. Then the wet cake was
dried under a reduced pressure. Thus black particles were
prepared.
[0231] Then 100 parts of the black particles were mixed with 0.5
parts of a hydrophobized silica R972 having a primary particle
diameter of 16 nm and manufactured by Nippon Aerosil Co., using a
Henshel mixer. The mixture was sieved using a mesh having openings
of 50 .mu.m to remove coarse particles.
[0232] Thus, a black toner T9-K was prepared.
[0233] Preparation of Yellow, Magenta and Cyan Toners
[0234] The procedure for preparation of the black toner T9-K was
repeated except that the black color master batch MB1-K was
replaced with the yellow color master batch MB1-Y, magenta color
master batch MB1-M or cyan color master batch MB1-C.
[0235] Thus, a yellow toner T9-Y, a magenta toner T9-M and a cyan
toner T9-C were prepared.
Toner Manufacturing Example 10
[0236] Preparation of Black Toner
[0237] The procedure for preparation of the black toner T9-K was
repeated except that the formulation of the oil phase liquid was
changed to the following.
12 Styrene-n-butyl acrylate copolymer 100 (St/nBA = 80:20 by
weight, weight average molecular weight Mw of 23000, Mw/Mn ratio of
5.6 and glass tran- sition temperature of 65.degree. C.) Black
color master batch MB1-K 12 Charge controlling agent 2 (BONTRON
E-84 from Orient Chemical Industries Co., Ltd.) Carnauba wax 5
Toluene 200
[0238] Thus a black toner T10-K was prepared.
[0239] Preparation of Yellow, Magenta and Cyan Toners
[0240] The procedure for preparation of the black toner T10-K was
repeated except that the black color master batch MB1-K was
replaced with the yellow color master batch MB1-Y, magenta color
master batch MB1-M or cyan color master batch MB1-C.
[0241] Thus, a yellow toner T10-Y, a magenta toner T10-M and a cyan
toner T10-C were prepared.
Toner Manufacturing Example 11
[0242] Preparation of Black Toner
[0243] The following components were contained in a beaker, and
mixed using HOMOMIXER.
13 Carnauba wax 40 Deionized water 56 Polyethylene glycol
nonylphenyl ether 4
[0244] The mixture was dispersed by HOMOMIXER while heated to
90.degree. C. to emulsify the wax. Then the wax emulsion was
cooled. When the wax emulsion was observed by a scanning electron
microscope, the average particle diameter of the wax particles was
0.2 .mu.m.
[0245] Then 12.5 parts of the wax emulsion were added to the dark
gray emulsion prepared in Example 9 (to which aluminum sulfate was
not added) to perform a coagulation treatment.
[0246] The mixture was heated to 70.degree. C. and the temperature
was maintained. The heated mixture was observed using a scanning
electron micrometer that the aggregated particles therein were
fused and united. Then the mixture was repeatedly subjected to a
filtering treatment followed by a washing treatment to prepare a
wet cake. Then the wet cake was dried under a reduced pressure.
Thus a black particles were prepared.
[0247] Then 100 parts of the black particles were mixed with 0.5
parts of a hydrophobized silica R972 having a primary particle
diameter of 16 nm and manufactured by Nippon Aerosil Co., using a
Henshel mixer. The mixture was sieved using a mesh having openings
of 50 .mu.m to remove coarse particles.
[0248] Thus, a black toner T11-K was prepared.
[0249] Preparation of Yellow, Magenta and Cyan Toners
[0250] The procedure for preparation of the black toner T11-K was
repeated except that the black color master batch MBL-K was
replaced with the yellow color master batch MB1-Y, the magenta
color master batch MB1-M or the cyan color master batch MB1-C.
[0251] Thus, a yellow toner T11-Y, a magenta toner T11-M and a cyan
toner T11-C were prepared.
Toner Manufacturing Example 12
[0252] Preparation of Black Toner
[0253] The procedure for preparation of the black toner T10-K in
Toner Manufacturing Example 10 was repeated except that polymethyl
methacrylate particles having an average particle diameter of 0.4
.mu.m (MP1000 from Soken Chemical & Engineering Co., Ltd.) were
added to the dark gray emulsion before aluminum sulfate was added
thereto.
[0254] Thus a black toner T12-K was prepared.
[0255] Preparation of Yellow, Magenta and Cyan Toners
[0256] The procedure for preparation of the black toner T12-K was
repeated except that the black color master batch MB1-K was
replaced with the yellow color master batch MB1-Y, the magenta
color master batch MB1-M or the cyan color master batch MB1-C.
[0257] Thus, a yellow toner T12-Y, a magenta toner T12-M and a cyan
toner T12-C were prepared.
Toner Manufacturing Example 13
[0258] Preparation of Black Toner
[0259] The procedure for preparation of the black toner T10-K in
Toner Manufacturing Example 10 was repeated except that the
styrene-n-butyl acrylate copolymer was replaced with 100 parts of a
polyester resin having an acid value of 3, a hydroxyl value of 25,
a weight average molecular weight (Mw) of 45000, a Mw/Mn ratio of
4.0 and a glass transition temperature Tg of 60.degree. C.
[0260] Thus a black toner T13-K was prepared.
[0261] Preparation of Yellow, Magenta and Cyan Toners
[0262] The procedure for preparation of the black toner T13-K was
repeated except that the black color master batch MB1-K was
replaced with the yellow color master batch MB1-Y, the magenta
color master batch MB1-M or the cyan color master batch MB1-C.
[0263] Thus, a yellow toner T13-Y, a magenta toner T13-M and a cyan
toner T13-C were prepared.
Toner Manufacturing Example 14
[0264] Preparation of Black Toner
[0265] The procedure for preparation of the black toner T10-K in
Toner Manufacturing Example 10 was repeated except that the
styrene-n-butyl methacrylate copolymer was replaced with a polyol
resin which had been prepared by reacting a dihydric phenol
compound with a glycidyl ether compound of an adduct of bisphenol A
with an alkylene oxide and which has a weight average molecular
weight (Mw) of 40000, a Mw/Mn ratio of 5.3 and a glass transition
temperature Tg of 63.degree. C.
[0266] Thus a black toner T14-K was prepared.
[0267] Preparation of Yellow, Magenta and Cyan Toners
[0268] The procedure for preparation of the black toner T14-K was
repeated except that the black color master batch MB1-K was
replaced with the yellow color master batch MB1-Y, the magenta
color master batch MB1-M or the cyan color master batch MB1-C.
[0269] Thus, a yellow toner T14-Y, a magenta toner T14-M and a cyan
toner T14-C were prepared.
Toner Manufacturing Example 15
[0270] Preparation of Black Toner
[0271] The procedure for preparation of the black toner T9-K in
Toner Manufacturing Method 9 was repeated except that the
formulation of the oil phase liquid was changed to the
following:
14 Polyester resin 100 (acid value of 3, hydroxyl value of 25,
weight average molecular weight (Mw) of 45000, ratio Mw/Mn of 4.0
and glass transition temperature of 60.degree. C.) Black color
master batch MB2-K 20 Toluene 200
[0272] Thus, a black toner T15-K was prepared.
[0273] Preparation of Yellow, Magenta and Cyan Toners
[0274] The procedure for preparation of the black toner T15-K was
repeated except that the black color master batch MB2-K was
replaced with the yellow color master batch MB2-Y, the magenta
color master batch MB2-M or the cyan color master batch MB2-C.
[0275] Thus, a yellow toner T15-Y, a magenta toner T15-M and a cyan
toner T15-C were prepared.
Toner Manufacturing Example 16 (Comparative Example)
[0276] Preparation of Black Toner
[0277] The procedure for preparation of the black toner T9-K in
Toner Manufacturing Method 9 was repeated except that the
formulation of the oil phase liquid was changed to the
following:
15 Polyester resin 108 (acid value of 3, hydroxyl value of 25,
weight average molecular weight (Mw) of 45000, ratio Mw/Mn of 4.0
and glass transition temperature of 60.degree. C.) Phthalocyanine
green 0.4 Carbon black 3.6 (MA60 manufactured by Mitsubishi
Chemical Corp.) Charge controlling agent 2 (BONTRON E-84
manufactured by Orient Chemical Industries Co., Ltd.) Carnauba wax
6 Toluene 200
[0278] Thus, a black toner T16-K was prepared. This toner is a
comparative toner because of being prepared without a kneading
process.
[0279] Preparation of Yellow, Magenta and Cyan Toners
[0280] The procedure for preparation of the black toner T16-K was
repeated except that the colorant (i.e., the combination of
phthalocyanine green and carbon black) was replaced with 4 parts of
Pigment Yellow 17, 4 parts of Pigment Red 57 or 4 parts of Pigment
Blue 15:3.
[0281] Thus, a yellow toner T16-Y, a magenta toner T16-M and a cyan
toner T16-C were prepared.
Toner Manufacturing Example 17 (Comparative Example)
[0282] Preparation of Black Toner
[0283] The following components were mixed using a mixer.
16 Polyester resin 100 (acid value of 3, hydroxyl value of 25, Mn
of 45000, Mw/Mn ratio of 4.0 and Tg of 60.degree. C.) Black color
master batch MB1-K 12 Charge controlling agent 2 (BONTRON E-84 from
Orient Chemical Industries Co., Ltd.) Carnauba wax 6
[0284] The mixture was kneaded using a two-roll mill upon
application of heat. The kneaded mixture was subjected to roll
cooling. The kneaded mixture was dissolved in 200 parts of toluene
contained in a tank while agitating with an agitator. Thus an oil
phase liquid was prepared.
[0285] On the other hand, the following components were mixed to
prepare an aqueous phase liquid.
17 Deionized water 700 Tricalcium phosphate 35 Sodium
dodecylbenzenesulfonate 1
[0286] The oil phase liquid was added to the aqueous phase liquid
while the mixture was agitated with a mixer, HOMOMIXER manufactured
by Tokushu Kika Kogyo Co., Ltd. At this point, the rotation speed
of the rotor of the mixer was controlled such that the oil phase
had a volume average particle diameter of about 10 .mu.m.
[0287] Then the mixture was heated to 50.degree. C. under a reduced
pressure to remove toluene therefrom. In addition, concentrated
hydrochloric acid was added to dissolve tricalcium phosphate. The
dispersion was repeatedly subjected to a washing treatment using
water followed by a filtering treatment to prepare a wet cake. Then
the wet cake was dried under a reduced pressure. Thus, black toner
particles were prepared.
[0288] Then 100 parts of the black toner particles were mixed with
0.5 parts of a hydrophobized silica R972 having a primary particle
diameter of 16 nm and manufactured by Nippon Aerosil Co., using a
Henshel mixer. The mixture was sieved using a mesh having openings
of 50 .mu.m to remove coarse particles.
[0289] Thus, a black toner T17-K was prepared. This toner is a
comparative toner because of being prepared without a coagulation
process.
[0290] Preparation of Yellow, Magenta and Cyan Toners
[0291] The procedure for preparation of the black toner T17-K was
repeated except that the black color master batch MB1-K was
replaced with MB1-Y, MB1-M or MB1-C.
[0292] Thus, a yellow toner T17-Y, a magenta toner T17-M and a cyan
toner T17-C were prepared.
Toner Manufacturing Example 18 (Comparative Example)
[0293] Preparation of Black Toner
[0294] The procedure for preparation of the black toner T17-K in
Toner Manufacturing Example 17 was repeated except that the
formulation of the kneaded mixture was changed to the
following:
18 Polyester resin 100 (acid value of 3, hydroxyl value of 25, Mn
of 45000, Mw/Mn ratio of 4.0 and Tg of 60.degree. C.) Black color
master batch MB2-K 20
[0295] Thus, a black color toner T18-K was prepared.
[0296] Preparation of Yellow, Magenta and Cyan Toners
[0297] The procedure for preparation of the black toner T18-K was
repeated except that the black color master batch MB2-K was
replaced with MB2-Y, MB2-M or MB2-C.
[0298] Thus, a yellow toner T18-Y, a magenta toner T18-M and a cyan
toner T18-C were prepared.
Toner Manufacturing Example 19 (Comparative Example)
[0299] Preparation of Black Toner
[0300] The procedure for preparation of the black toner T17-K in
Toner Manufacturing Example 17 was repeated except that the
formulation of the kneaded mixture was changed to the
following:
19 Styrene-n-butyl acrylate copolymer 100 (having a St/nBA ratio of
80/20 by weight, weight average molecular weight Mw of 23000, a
ratio Mw/Mn of 11.0, glass transition temperature of 65.degree. C.
and crosslinked with divinylbenzene) Black color master batch MB1-K
12 Charge controlling agent 2 (BONTRON E-84 manufactured by Orient
Chemical Industries Co., Ltd.) Carnauba Wax 6
[0301] Thus, a black color toner T19-K was prepared.
[0302] Preparation of Yellow, Magenta and Cyan Toners
[0303] The procedure for preparation of the black toner T19-K was
repeated except that the black color master batch MB1-K was
replaced with MB1-Y, MB1-M or MB1-C.
[0304] Thus, a yellow toner T19-Y, a magenta toner T19-M and a cyan
toner T19-C were prepared.
Toner Manufacturing Example 20 (Comparative Example)
[0305] Preparation of Black Toner
[0306] The procedure for preparation of the black toner T17-K in
Toner Manufacturing Example 17 was repeated except that the
formulation of the kneaded mixture was changed to the
following:
20 Polyester resin 108 (acid value of 3, hydroxyl value of 25, Mn
of 45000, Mw/Mn ratio of 4.0 and Tg of 60.degree. C.)
Phthalocyanine green 0.4 Carbon black 3.6 (MA60 manufactured by
Mitsubishi Chemical Corp.) Charge controlling agent 2 (BONTRON E-84
manufactured by Orient Chemical Industries Co., Ltd.) Carnauba wax
6
[0307] Thus, a black color toner T20-K was prepared.
[0308] Preparation of Yellow, Magenta and Cyan Toners
[0309] The procedure for preparation of the black toner T20-K was
repeated except that the colorant (i.e., the combination of
phthalocyanine green and carbon black) was replaced with 4 parts of
Pigment Yellow 17, 4 parts of Pigment Red 57 or 4 parts of Pigment
Blue 15:3.
[0310] Thus, a yellow toner T20-Y, a magenta toner T20-M and a cyan
toner T20-C were prepared.
Toner Manufacturing Example 21 (Comparative Example)
[0311] Preparation of Black Toner
[0312] The procedure for preparation of the black toner T17-K in
Toner Manufacturing Example 17 was repeated except that the
formulation of the kneaded mixture was changed to the
following:
21 Styrene-n-butyl acrylate copolymer 100 (having a St/nBA ratio of
80/20 by weight, weight average molecular weight Mw of 23000, a
ratio Mw/Mn of 11.0, glass transition temperature of 65.degree. C.
and crosslinked with divinylbenzene) Black color master batch MB2-K
20
[0313] Thus, a black toner T21-K was prepared.
[0314] Preparation of Yellow, Magenta and Cyan Toners
[0315] The procedure for preparation of the black toner T21-K was
repeated except that the black color master batch MB1-K was
replaced with the yellow color master batch MB1-Y, the magenta
color master batch MB1-M or the cyan color master batch MB1-C.
[0316] Thus, a yellow toner T21-Y, a magenta toner T21-M and a cyan
toner T21-C were prepared.
[0317] Preparation of Carrier
[0318] When each of the above-prepared toners was mixed with a
carrier to be evaluated as a two-component developer, a ferrite
carrier having an average particle diameter of 50 .mu.m having a
surface on which a silicone resin having a thickness of 0.3 .mu.m
was formed was used. The two component developer was prepared by
mixing 100 parts of the carrier with 5 parts of a toner using a
TURBULA mixer to charge the toner.
[0319] Evaluation Method
[0320] (Evaluation Machine A)
[0321] Each color developer combination (i.e., a set of a black
toner, a yellow toner, a magenta toner and a cyan toner) was set in
a full color laser printer IPSIO 5000 manufactured by Ricoh Co.,
Ltd. In the printer, four color toner images were formed one by one
on a belt-shaped photoreceptor using a developing device having
four color developing sections each including a different one
component color developer. The resultant color toner images were
transferred on an intermediate transfer medium one by one to form a
full color toner image thereon. The full color toner image was then
transferred onto a receiving paper at the same time. The developing
method was a reverse developing method.
[0322] (Evaluation Machine B)
[0323] Each color developer combination was set in a tandem type
full color LED printer GL8300 manufactured by Fujitsu Ltd. In the
printer, four color toner images were formed on four drum-shaped
photoreceptors, respectively, using a developing device having four
color developing sections each including a different one component
color developer. The developing method was a reverse developing
method.
[0324] (Evaluation Machine C)
[0325] Each color developer combination was set in a full color
laser copier Imagio Color 2800 manufactured by Ricoh Co., Ltd. In
the copier, four color toner images were formed one by one on a
drum-shaped photoreceptor using a developing device having four
color developing sections each including a different two component
color developer. The developing method was a reverse developing
method. The color toner images were transferred one by one onto an
intermediate transfer medium to form a full color toner image
thereon. The full color toner image was then transferred on a
receiving material.
[0326] In the evaluation machines A and B, each developing section
has a developing roller made of an elastic material and a stainless
blade which controls the thickness of the toner layer on the
surface of the developing blade (namely, the developing section is
a non-magnetic one component developing section).
[0327] In addition, the silicone oil applicator which applies a
silicone oil to the fixing device was removed from the evaluation
machines A, B and C.
[0328] A running test in which 10000 copies of an original having
an image area of 7% were produced using each color developer
combination was performed in each evaluation machine.
[0329] The following items were evaluated.
[0330] (Evaluation Items)
[0331] 1) Image Density (ID)
[0332] Image density of a fixed solid image formed on a receiving
paper, TYPE 6000 PAPER from Ricoh Co., Ltd. was measured by a
spectrodensitometer X-RITE 938 from X-Rite Co. The averaged image
density of four color images is shown in Table 1.
[0333] 2) Gloss
[0334] Gloss of a solid image formed on a receiving paper, TYPE
6000 PAPER from Ricoh Co., Ltd. was measured by a gloss meter from
Nippon Denshoku Kogyo K.K. while the incident angle was set to be
60.degree.. The higher the gloss, the glossier the image. In
general, full color images having a proper gloss are desired by
users.
[0335] 3) Charge Quantity (Q/M) after Running Test
[0336] When a one component developer was used, the charge quantity
of the developer was determined as follows:
[0337] (a) the developer on the developing roller was collected by
sucking when the developer develops a solid image;
[0338] (b) the charge quantity of the collected developer was
measured by a Q meter; and
[0339] (c) a ratio (Q/M) of the charge quantity (Q) to the weight
(M) of the collected developer is determined.
[0340] The averaged charge quantity (Q/M) of a combination of four
color developers is shown in Table 1.
[0341] When a two component developer was used, the developer was
sampled after the running test and then the charge quantity thereof
was measured by the following blow-off method:
[0342] (a) airing the sampled developer with compressed air to
separate the toner from the carrier of the developer;
[0343] (b) the charge quantity of the toner is measured by a Q
meter;
[0344] (c) a ratio Q/M of the charge quantity (Q) to the weight (M)
of the toner is determined.
[0345] The unit of the charge quantity is -.mu.C/g.
[0346] 4) Fixable temperature range (T)
[0347] After the running test, each of the evaluation machines A, B
and C was modified such that the temperature of the fixing unit can
be changed. A stripe black toner image in which four color images
are overlaid was formed and fixed while the temperature of the
fixer was changed, to determine the lower and upper limit of the
fixable temperature of the toner image. In this case, the silicone
oil applicator was not used. The difference between the upper
fixable temperature and the lower fixable temperature, which is the
fixable temperature range, is shown in Table 1.
[0348] The lower fixable temperature was defined as the minimum
temperature of the temperature range in which the toner image can
be fixed without causing a chipping problem when the toner image is
subjected to a spiral scoring test. The upper fixable temperature
was defined as the maximum temperature of the temperature range in
which the toner image could be fixed without causing a hot offset
problem.
[0349] The results are shown in Table 1.
22 TABLE 1 Evalua- Devel- tion Gloss Q/M .DELTA.T oper machine ID
(%) (-.mu.C/g) (.degree. C.) Ex. 1 T1-YMCK A 1.84 15 36 25 Ex. 2-1
T2-YMCK A 1.90 18 38 95 Ex. 2-2 T2-YMCK B 2.01 21 22 95 Ex. 2-3
T2-YMCK C 1.75 19 28 100 Ex. 3 T3-YMCK A 1.82 15 34 90 Ex. 4
T4-YMCK A 1.90 20 40 120 Ex. 5 T5-YMCK A 2.10 35 33 90 Ex. 6
T6-YMCK A 2.15 38 30 85 Comp. T7-YMCK A 1.15 8 15 30 Ex. 1 Comp.
T8-YMCK A 1.23 6 11 35 Ex. 2 Ex. 7 T9-YMCK A 3.17 28 34 30 Ex. 8-1
T10-YMCK A 3.22 33 39 100 Ex. 8-2 T10-YMCK B 3.26 36 21 105 Ex. 8-3
T10-YMCK C 2.95 34 30 100 Ex. 9 T11-YMCK A 3.09 31 35 65 Ex. 10
T12-YMCK A 3.20 35 40 130 Ex. 11 T13-YMCK A 3.58 64 31 95 Ex. 12
T14-YMCK A 3.63 70 32 90 Ex. 13 T15-YMCK A 2.87 26 17 60 Comp.
T16-YMCK A 0.71 10 29 95 Ex. 3 Comp. T17-YMCK A 1.96 15 35 45 Ex. 4
Comp. T19-YMCK A 1.91 5 38 85 Ex. 5 Comp. T17-YMCK B 2.03 18 25 55
Ex. 6 Comp. T19-YMCK B 1.89 8 28 100 Ex. 7 Comp. T18-YMCK A 1.74 13
8 20 Ex. 8 Comp. T20-YMCK A 1.15 16 15 30 Ex. 9 Comp. T21-YMCK A
1.62 7 11 35 Ex. 10
[0350] As can be under stood from Table 1, the resultant toner has
good tinting power and color reproducibility, and maintains good
charge properties even when used for a long period of time because
the toner constituents including a binder resin and a colorant are
kneaded upon application of heat.
[0351] When a polyester resin or a polyol resin is used as the
binder resin, the resultant toner further has good fixability and a
releasability.
[0352] The toner of the present invention can be preferably used as
a one component developer or for a two component developer.
[0353] This document claims priority and contains subject matter
related to Japanese Patent Application No. 2001-103847, filed on
Apr. 2, 2001, incorporated herein by reference.
[0354] Having now fully described the invention, it will be
apparent to one of ordinary skill in the art that many changes and
modifications can be made thereto without departing from the spirit
and scope of the invention as set forth therein.
* * * * *