U.S. patent application number 11/080421 was filed with the patent office on 2005-07-21 for image forming material, method and device for removing images, and image forming process and apparatus.
Invention is credited to Mochizuki, Hidehiro, Saitou, Tadashi.
Application Number | 20050158487 11/080421 |
Document ID | / |
Family ID | 19064478 |
Filed Date | 2005-07-21 |
United States Patent
Application |
20050158487 |
Kind Code |
A1 |
Mochizuki, Hidehiro ; et
al. |
July 21, 2005 |
Image forming material, method and device for removing images, and
image forming process and apparatus
Abstract
An image forming material for forming an image on an image
recording material with an image binding force being established
between the image and the image recording material, the image
forming material containing an image forming substance, and a
binding force reducing substance which reduces the image binding
force when the image is heated. A method of removing an image
formed on an image recording material with a binding force being
established between the image and the recording material by
contacting a stripping member with the image with heating under
pressure. A binding force reducing substance may be contained in
the surface of the stripping member or in the image recording
material.
Inventors: |
Mochizuki, Hidehiro;
(Numazu-shi, JP) ; Saitou, Tadashi; (Yokohama-shi,
JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
19064478 |
Appl. No.: |
11/080421 |
Filed: |
March 16, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11080421 |
Mar 16, 2005 |
|
|
|
10207995 |
Jul 31, 2002 |
|
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Current U.S.
Class: |
428/32.34 |
Current CPC
Class: |
G03G 7/0086 20130101;
G03G 9/09392 20130101; G03G 9/09708 20130101; C09D 11/02 20130101;
G03G 9/09783 20130101; G03G 11/00 20130101; G03G 9/09733 20130101;
G03G 9/0926 20130101; G03G 9/08782 20130101; B41M 7/0009 20130101;
G03G 9/0821 20130101; G03G 8/00 20130101; G03G 21/00 20130101; C09D
11/30 20130101 |
Class at
Publication: |
428/032.34 |
International
Class: |
B41M 005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2001 |
JP |
2001-232576 |
Claims
1-53. (canceled)
54. An image forming material suitably applicable for a method of
removing an image which comprises contacting a stripping member
under pressure with an image recording material while heating the
image to reduce an image binding force established between the
image and image recording material; and peeling the image recording
material from the stripping member to transfer the image from the
image recording material to the stripping member, the image forming
material comprising: an image forming substance; and a binding
force reducing substance which reduces the image binding force when
the image is heated.
55. An image forming material as claimed in claim 54, wherein the
image forming substance comprises a binder resin.
56. An image forming material as claimed in claim 54, wherein the
binding force reducing substance is a low melting point substance
which reduces the image binding force when the image is heated at a
temperature higher than the softening point of the low melting
point substance.
57. An image forming material as claimed in claim 56, wherein the
low melting point substance has a hydrophilic group.
58. An image forming material as claimed in claim 56, wherein the
low melting point substance has a hydrophilic group and a
hydrophobic group.
59. An image forming material as claimed in claim 56, wherein the
image forming substance is in the form of solid particles, wherein
the low melting point substance is comprised in the solid
particles, and wherein the low melting point substance is present
in an amount of 5 to 75% by weight based on a total weight of the
image forming substance and the low melting point substance.
60. An image forming material as claimed in claim 55, wherein the
binder resin is a thermally crosslinked resin.
61. A method of removing an image of an image forming material
formed on an image recording material with an image binding force
being established between said image and said image recording
material, the method comprising: providing a stripping member
having a surface resin layer comprising a binding force reducing
substance, the binding force reducing substance being adapted to
reduce the image binding force when the image is heated in the
presence of the binding force reducing substance; contacting the
surface of the stripping member under pressure with the image on
the image recording material while heating the image to reduce the
image binding force established between the image and the image
recording material; and peeling the image recording material from
the stripping member to transfer the image from the image recording
material to the stripping member, wherein the image forming
material comprises: an image forming substance; and a binding force
reducing substance which reduces the image binding force when the
image is heated.
62. A method as claimed in claim 61, wherein the image has a
viscoelasticity of 10.sup.4 Pa to 10.sup.6 Pa by said heating.
63. A method as claimed in claim 61, wherein the image binding
force is reduced to 2.0 kg/cm.sup.2 or less by said heating.
64. A method as claimed in claim 61, wherein the image has been
formed on the image recording material by fusing and fixing the
image forming material thereon.
65. A method as claimed in claim 64, wherein the heating is at a
temperature higher than the fixing temperature at which said image
has been formed on the image recording material.
66. A device for removing an image of an image forming material
formed on an image recording material, the device comprising. a
stripping member providing an adhesion strength between the
stripping member and the image which is not smaller than the image
binding force; means for contacting the stripping member with the
image on the image recording material under pressure; a heater for
heating the image during its contact with the stripping member
under pressure, thereby reducing the binding force; and drive means
for separating the image recording material from the stripping
member so that the image is transferred from the image recording
material to the stripping member, wherein the image forming
material comprises: an image forming substance; and a binding force
reducing substance which reduces the image binding force when the
image is heated.
67. A device for removing an image as claimed in claim 66, wherein
the stripping member has a surface layer which comprises a binding
force reducing substance adapted to reduce the image binding force
when the image is heated in the presence of the binding force
reducing substance, the surface layer is adapted to release the
binding force reducing substance when heated so that an adhesion
strength which is not smaller than the image binding force is
established between the stripping member and the image after the
release of the binding force reducing substance.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to an image forming
material and, more specifically, to an image forming material for
forming a stable image on an image recording material by, for
example, ordinary printing such as letterpress printing or
lithographic printing, electrophotography, ink jet printing,
thermal transfer recording or writing such as with crayon or pens,
wherein the image is able to be removed from the image recording
material. The present invention is also directed to a method for
removing an image on an image recording material, to a device for
carrying out the method, to a process for forming an image and to
an apparatus for carrying out the process.
[0002] With rapid progress of various information recording and
transmitting means, the level of information output has very
increased and paper consumption has increased significantly. In an
effort to reduce the consumption of paper and to conserve forest
resources, recycling of waste paper is now an important concern.
Thus, many methods have been hitherto proposed to recycle waste
papers, especially toner image-bearing papers produced by
electrophotography.
[0003] One known method is to treat a paper to improve erasability
of the toner images. Such a method has a problem because the
recyclable paper is not available at a low cost. Another method is
to use an erasable toner whose color is erasable by irradiation
thereof with a light (Japanese Patent No. 2,960,229). This method
has a problem because the discolored material remaining on the
paper adversely affect the surface smoothness thereof so that it is
difficult to reuse same for image formation. Japanese Laid-Open
Patent Publication No. H08-146649 proposes a toner containing a
surfactant to improve water absorbing efficiency. This toner,
however, requires a wet treatment to remove the toner images from
the image-bearing recording material and, therefore, has a problem
because the size of the paper increases due to swelling.
SUMMARY OF THE INVENTION
[0004] It is, therefore, an object of the present invention to
provide an image forming material which can form a stable and high
grade image on an ordinary image recording material such as plain
paper and which permits the removal of the image from the recording
material.
[0005] Another object of the present invention is to provide an
image forming material of the above-mentioned type which permits
the removal of the image from the recording material without using
a wet treatment and which allows for the reuse of the recording
material for image formation.
[0006] It is a further object of the present invention to provide a
simple method and a device for removing an image from an
image-bearing recording material.
[0007] It is yet a further object of the present invention to
provide a process and a apparatus for forming an image on an image
recording material.
[0008] In accomplishing the foregoing objects, there is provided in
accordance with one aspect of the present invention an image
forming material for forming an image on an image recording
material with an image binding force being established between said
image and said image recording material, said image forming
material comprising an image forming substance, and a binding force
reducing substance which reduces said image binding force when said
image is heated.
[0009] In another aspect, the present invention provides a method
of removing an image of an image forming material according to
claim 1 formed on an image recording material, said method
comprising the steps of:
[0010] contacting a stripping member under pressure with said image
on said image recording material while heating said image to reduce
said image binding force; and
[0011] peeling said image recording material from said stripping
member to transfer said image from said image recording material to
said stripping member.
[0012] The present invention also provides a method of removing an
image of an image forming material formed on an image recording
material with an image binding force being established between said
image and said image recording material, said method comprising the
steps of:
[0013] providing a stripping member having a surface resin layer
comprising a binding force reducing substance, said binding force
reducing substance being adapted to reduce said image binding force
when said image is heated in the presence of said binding force
reducing substance;
[0014] contacting said surface of said stripping member under
pressure with said image on said image recording material while
heating said image to reduce said image binding force established
between said image and said image recording material; and
[0015] peeling said image recording material from said stripping
member to transfer said image from said image recording material to
said stripping member.
[0016] In a further aspect, the present invention provides a device
for removing an image of the above image forming material formed on
an image recording material, said device comprising:
[0017] a stripping member providing an adhesion strength between
said stripping member and said image which is not smaller than said
image binding force;
[0018] means for contacting said stripping member with said image
on said image recording material under pressure;
[0019] a heater for heating said image during its contact with said
stripping member under pressure, thereby reducing said binding
force; and
[0020] drive means for separating said image recording material
from said stripping member so that said image is transferred from
said image recording material to said stripping member.
[0021] In a further aspect, the present invention provides a device
for removing an image of an image forming material formed on an
image recording material with an image binding force being
established between said image and said image recording material,
said device comprising:
[0022] a stripping member having a surface layer comprising a
binding force reducing substance adapted to reduce said image
binding force when said image is heated in the presence of said
binding force reducing substance, said surface layer is adapted to
release said binding force reducing substance when heated so that
an adhesion strength which is not smaller than said image binding
force is established between said stripping member and said image
after the release of said binding force reducing substance;
[0023] means for contacting said stripping member with said image
on said image recording material under pressure;
[0024] a heater for heating said image during its contact with said
stripping member under pressure, thereby reducing said binding
force established between said image and said image recording
material; and
[0025] drive means for separating said image recording material
from said stripping member so that said image is transferred from
said image recording material to said stripping member.
[0026] In a further aspect, the present invention provides an image
forming process comprising depositing the above image forming
material on an image recording material. In a further aspect, the
present invention provides an image forming process comprising
depositing an image forming material on an image recording
material, and removing the image formed on said image recording
material in accordance with the above image removing method to
obtain a recycled recording material, and forming an image on said
recycled recording material.
[0027] In a further aspect, the present invention provides an image
forming process comprising forming an image on an image recording
material with an image binding force being established between said
image and said image recording material, wherein before said image
is formed, a binding force reducing substance is deposited on said
image recording material, said binding force reducing substance
reducing said image binding force when said image is heated.
[0028] In a further aspect, the present invention provides an image
forming apparatus comprising an image forming device for forming an
image on an image recording material, and the above image removing
device.
[0029] In a further aspect, the present invention provides an image
forming process comprising forming an image on an image recording
material with an image binding force being established between said
image and said image recording material, wherein before said image
is formed, a binding force reducing substance is deposited on said
image recording material, said binding force reducing substance
reducing said image binding force when said image is heated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Other objects, features and advantages of the present
invention will become apparent from the detailed description of the
preferred embodiments of the invention which follows, when
considered in the light of the accompanying drawing, in which:
[0031] FIG. 1 is a cross-sectional view diagrammatically
illustrating an embodiment of an image removing device according to
the present invention connected to an image forming apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
[0032] According to the present invention, an image formed on an
image recording material with a binding force being established
between the image and the recording material is removed by
contacting a stripping member with the image with heating under
pressure. As a consequence of such a contact, the image is softened
to reduce the binding force while increasing an adhesion strength
between the image and the stripping member.
[0033] In one preferred embodiment, the heating under pressure is
carried out in the presence of a binding force reducing substance.
The binding force reducing substance which is present in an
interface between the image and the recording material reduces the
binding force established between the image and the recording
material to permit the removal of the image from the recording
material. Thus, when the recording material is peeled from the
stripping member, the image is transferred from the recording
material to the stripping member. The resulting recording material
may be recycled.
[0034] It is desirable that the image binding force is reduced to
2.0 kg/cm.sup.2 or less by the heating for reasons of completely
removing the image from the image recording material. It is also
desirable that the image binding force is 1 to 4.5 kg/cm.sup.2 or
less at room temperature.
[0035] As used herein the term "image binding force" is measured
using a probe tack tester (Model TAC-II manufactured by Reska
Inc.). The image binding force at room temperature is measured as
follows. A pressure sensitive adhesive double coated tape is
adhered to a tip (diameter: 5 mm) of a probe of the tester. The
probe is extended at a rate of 120 mm/min, pressed against the
sample at a probe contact pressure of 500 gf per area of the probe
tip for a dwell time of 10 seconds and then retracted at a rate of
600 mm/min. The force required to free the probe from the sample
(i.e. to remove the image from the recording material), measured in
grams/cm.sup.2, is read from the indicator on the tester. These
steps are performed at room temperature. The image binding force at
elevated temperature is measured in the same manner as above except
that a 100 .mu.m thick stripping film made of a polyether ether
ketone (SUMILITE FS-1100C manufactured by Sumitomo Bakelite Inc.)
is bonded on a tip of the probe in place of the double coated tape
and that the test is conducted at a given elevated temperature.
[0036] In another preferred embodiment, the present invention
provides an image forming material for forming an image on an image
recording material with an image binding force being established
between the image and the image recording material, wherein the
image forming material comprises an image forming substance, and a
binding force reducing substance which reduces the image binding
force when the image is heated. With this embodiment, the image
recording material need not be specifically treated. Further, mere
heating under pressure is sufficient to remove the image. Such a
removal treatment may be suitably carried out using a toner image
fixing device.
[0037] It is preferred that the image forming substance further
comprises a binder resin. The binder resin serves to provide
sufficient cohesive force in the heated image layer so that the
image is not destroyed during peeling thereof from the image
recording material. To maintain a suitable cohesive force, the
binder resin is preferably such that the image formed from the
binder resin-containing image forming substance has a
viscoelasticity of 10.sup.4 Pa to 10.sup.6 Pa when heated for the
removal of the image from the recording material. The binder resin
is preferably a thermally crosslinked resin to attain suitable
viscoelasticity.
[0038] A toner for use in electrophotography generally contains a
binder and a colorant and is suitably used as the image forming
substance of the image forming material of the present invention.
When the image forming material is a crayon as an writing
instrument or a thermal transfer ribbon as a thermal transfer
recording using a thermal head, the use of a binder resin is
preferred.
[0039] The binding force reducing substance is preferably a low
melting point substance. When the image is heated at a temperature
higher than the softening point of the low melting point substance,
the low melting point substance is melted during heating and is
easily located in an interfase between the image and the recording
material to prevent binding of the image to the recording material
and to permit easy removal of the image from the recording
material. When the image has been fixed to the recording material
by heating under pressure, such as in the case of toner image
fixation, the low melting point substance serves to prevent
establishment of an excessively high binding force between the
image and the recording material. It is preferred that the low
melting point substance, when melted, should not function as a
solvent for components of the image forming substance, since
otherwise the binding force between the image and the recording
material would undesirably excessively increase.
[0040] It is preferred that a low melting point substance have a
hydrophilic group when the image forming substance is a hydrophobic
in nature, such as a toner, since the low melting point substance
when melted is separated from the image to accelerate the
accumulation of the low melting point substance in the interface
between the image and the recording material. In addition, when the
recording material is made of cellulose, the melted low melting
point substance having hydrophilic groups facilitate the removal of
the image from the recording material. Although not wishing to be
bound by the theory, the hydrophilic groups of the low melting
point substance are considered to interact with the hydroxyl groups
of the cellulose through hydrogen bonding, thereby preventing the
penetration of the low melting point substance deep into the
recording material.
[0041] It is also preferred that the low melting point substance
have both hydrophilic and hydrophobic (lipophilic) groups,
especially when the image forming substance and/or the stripping
member have lipophilic (hydrophobic) groups, since the amount of
the low melting point substance remaining on the recording material
after the transfer of the image from the recording material to the
stripping member is reduced and since the recyclability of the
recording material may be improved.
[0042] The low melting point substance is preferably a compound
represented by the following formula:
(R).sub.n.(Z).sub.m
[0043] wherein R represents an organic group, Z is a hydrophilic
group, n is an integer of 1 to 3 determined according to the
valency of Z, and m is an integer of at least 1.
[0044] In the above formula, R is preferably selected from
--PO.sub.3H.sub.2, .dbd.POH, --OH, --O--, --COOH,
--CH(OH)CH.sub.2COOH, --OCOY (where Y is an alkyl group which may
have one or more substitutents, an aryl group which may have one or
more substitutents, or an aralkyl group which may have one or more
substitutents), --SO.sub.3H, .dbd.N.sup.+X.sup.- (where X is a
halogen atom), --CONH.sub.2 and --NH.sub.2, n is an integer of 1 to
3 determined according to the valency of Z, and m is at least 1 but
is 1 only when Z is .dbd.PO.sub.2H or .dbd.N.sup.+X.sup.-.
[0045] In the above formula, R is preferably an alkyl group having
1 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, most
preferably 6 to 22 carbon atoms, or an aralkyl group having 7 to 40
carbon atoms, more preferably 7 to 30 carbon atoms. The alkyl and
aralkyl groups may contain one or more halogen atoms such as
fluorine atoms.
[0046] The low melting point substance is preferably a dialkyl
compound having a hydrophilic group, such as (R).sub.2PO.sub.2H,
for reasons of prevention of absorption of moisture. The low
melting point substance is also preferably an aromatic
group-containing compound for reasons of prevention of absorption
of moisture. The hydrophobicity (lipophilicity) and steric
hindrance of the dialkyl groups and the aromatic group are
considered to prevent water molecules from entering in the image
forming material so that the moisture absorbing property thereof is
suppressed. When the image forming material for use in, for
example, developing electrostatic latent images has moisture
absorbing properties and is hygroscopic in nature, a problem such
as agglomeration thereof is apt to be caused during storage. Thus,
it is desirable that the image forming material hardly absorbs
water.
[0047] In a preferred embodiment, the image forming substance is in
the form of solid particles, such as toner, while the low melting
point substance is bound to outer surfaces of the solid particles.
In this case, the low melting point substance is preferably present
in an amount of 1 to 50% by weight, more preferably 5 to 20% by
weight, based on the a total weight of the image forming substance
and the low melting point substance for reasons of suitable binding
force reducing efficiency during heating stage while maintaining
suitable binding force during non-heating stage and, hence,
suitable storage stability of the image-bearing recording
material.
[0048] In another embodiment, the image forming substance is in the
form of solid particles, such as toner, while the low melting point
substance is contained in the solid particles. In this case, the
low melting point substance is preferably present in an amount of 5
to 75% by weight, more preferably 10-30% by weight, based on the a
total weight of the image forming substance and the low melting
point substance for reasons of suitable binding force reducing
efficiency during heating while maintaining suitable binding force
during non-heating.
[0049] The low melting point substance preferably has a melting
point of 60 to 150.degree. C., more preferably 70 to 120.degree. C.
for reasons of suitable binding force reducing efficiency during
heating while maintaining suitable binding force during
non-heating. The low melting point substance is preferably in the
form of powder having an average particle diameter of 0.1 to 20
.mu.m, more preferably 0.5-10 .mu.m for reasons of ensuring
suitable image quality of the image forming substance and suitable
binding force reducing efficiency.
[0050] In another preferred embodiment, the image forming material
comprises, in addition to the image forming substance and the
binding force reducing substance, fine support particles which are
infusible or which have a melting point higher than that of the low
melting point substance. In this case, the low melting point
substance is bound to the fine support particles to improve the
binding force reducing efficiency. The fine support particles serve
to reduce an adverse affect by the low melting point substance and
to improve storage stability of the image-bearing recording
material. The binding of the low melting point substance with the
fine support particles may be, for example, ionic bonding or
hydrogen bonding.
[0051] The fine support particles to which the low melting point
substance is bound have preferably an average particle diameter of
0.1 to 20 .mu.m, more preferably 0.5-10 .mu.m for reasons of
ensuring suitable image quality of the image forming substance and
suitable binding force reducing efficiency of the low melting point
substance. The low melting point substance is present in an amount
of 10 to 90% by weight based on a total weight of the low melting
point substance and the fine support particles to ensure suitable
binding force reducing effect during heating.
[0052] The fine support particles to which the low melting point
substance is bound may be bound to outer surfaces of the solid
particles of the image forming substance. In this case, the fine
support particles to which the low melting point substance is bound
are present in an amount of 1 to 50% by weight, preferably 5 to 30%
by weight based on the a total weight of the image forming
substance, the fine support particles and the low melting point
substance for reasons of suitable binding force reducing effect
during heating while maintaining suitable binding force during
non-heating.
[0053] Alternately, the fine support particles to which the low
melting point substance is bound may be contained in the solid
particles of the image forming substance. In this case, the fine
support particles to which the low melting point substance is bound
are present in an amount of 5 to 75% by weight, preferably 10 to
40% by weight, based on the a total weight of the image forming
substance, the fine support particles and the low melting point
substance for reasons of suitable binding force reducing effect
during heating while maintaining suitable binding force during
non-heating.
[0054] As described previously, the low melting point substance
preferably has hydrophilic groups and hydrophobic groups. In this
case, it is also preferred that the fine support particles have
hydrophilic groups for reasons of improved removal efficiency of
the image from the recording material and improved moisture
absorption-preventing effect. Although not wishing to be bound by
the theory, the hydrophilic groups of the low melting point
substance are considered to interact with the hydrophilic groups of
the fine support particles through hydrogen bonding, so that the
low melting point substance is bound by the fine support particles
during heating, thereby preventing the penetration of the low
melting point substance into the recording material and reducing
moisture absorbing properties. In addition, the presence of the
hydrophobic groups in the low melting point substance can reduce
the moisture absorbing properties.
[0055] In another embodiment, the image forming material comprises,
in addition to the image forming substance, the low melting point
substance, fine support particles which are infusible or which have
a melting point higher than that of the low melting point
substance, wherein the low melting point substance is held within
the fine support particles.
[0056] In this case, too, the low melting point substance is
preferably present in an amount of 10 to 90% by weight based on a
total weight of the low melting point substance and the fine
support particles.
[0057] The fine support particles in which the low melting point
substance is held may be bound to outer surfaces of the solid
particles of the image forming substance. In this case, the fine
support particles in which the low melting point substance is held
are preferably present in an amount of 1 to 50% by weight, more
preferably 5 to 30% by weight, based on the a total weight of the
image forming substance, the fine support particles and the low
melting point substance.
[0058] Alternatively, the fine support particles in which the low
melting point substance is held may be contained in the solid
particles of the image forming substance. In this case, the fine
support particles in which the low melting point substance is held
are preferably present in an amount of 5 to 75% by weight, more
preferably 10 to 40% by weight, based on the a total weight of the
image forming substance, the fine support particles and the low
melting point substance. The fine support particles in which the
low melting point substance is held preferably have an average
particle diameter of 0.1 to 20 .mu.m, more preferably 0.5-10
.mu.m.
[0059] In another embodiment, the fine support particles are porous
particles. In this case, the low melting point substance is
preferably incorporated into the pores of the fine support
particles, since the amount of the low melting point substance may
be increased to facilitate the reduction of the image binding force
between the image and the recording material during heating, while
maintaining suitable image binding force during non-heating
stage.
[0060] The fine support particles may be, for example, those of the
following materials various carbides, such as silicon carbide,
boron carbide, titanium carbide, zirconium carbide, hafnium
carbide, vanadium carbide, tantalum carbide, niobium carbide,
tungsten carbide, chromium carbide, molybdenum carbide, calcium
carbide and diamond carbon random; various nitrides such as boron
nitride, titanium nitride and zirconium nitride; various bromides
such as zirconium bromide; various oxides, such as titanium oxide,
calcium oxide, magnesium oxide, zinc oxide, copper oxide, aluminum
oxide, silica and colloidal silica; various sulfides such as
molybdenum disulfide; various fluorides such as magnesium fluoride
and carbon fluoride; various metal soaps, such as aluminum
stearate, calcium stearate, zinc stearate and magnesium stearate;
various minerals such as talc and bentonite; various metals, such
as cobalt, iron, nickel, aluminum, copper, lead, magnesium, tin,
zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese,
selenium, titan, tungsten and vanadium, and alloys thereof; various
titanic acid compounds, such as calcium titanate, magnesium
titanate and strontium titanate; various polymer particles, which
are formed into particles by a wet polymerization method such as an
emulsion polymerization method, a soap-free emulsion polymerization
method and a non-aqueous dispersion polymerization method, and a
vapor phase method, such as styrene, (metha)acrylic polymers,
polyolefins, fluorine-containing (metha)acrylic polymers,
nitrogen-containing (metha)acrylic polymers, epoxy resins, silicone
resins, benzoguanamine resins, melamine resin; various natural
polymers, such as starch (sweet potato starch, potato starch,
tapioca starch, wheat starch, corn starch), mannan
(devil's-tongue), seaweeds (funorin, agar, sodium alginate), plant
mucilage (hibiscus, tragacanth, gum arabic), microbiological
mucilage (dextran, levan), and protein (glue, gelatin, casein,
collagen); various semi-synthetic polymers, such as cellulose
(viscose, methyl cellulose, ethyl cellulose, hydroxyethyl
cellulose, carboxy methyl cellulose), and starch (soluble starch,
carboxy methyl starch, dialdehyde starch); and various synthetic
polymers such as polyvinyl alcohol, sodium polyacrylate,
Polyethylene oxide and isobutyrene-maleic anhydride copolymers.
These fine support particles may be used alone or in combination.
If desired, the above inorganic fine support particles may be
treated by a known suitable method with a conventionally used
hydrophobisizing agent, such as a silane coupling agent, a titanate
coupling agent, silicone oil and silicone vanish.
[0061] In another embodiment, the image forming substance is in the
form of solid particles, wherein the low melting point substance is
contained in outer peripheral regions of the solid particles, and
wherein the low melting point substance is present in an amount of
5 to 75% by weight based on the a total weight of the image forming
substance and the low melting point substance. Since the low
melting point substance is present predominantly in an outer region
of each of the image forming substance particles, suitable binding
force reducing effect is obtainable even when the amount of the low
melting point substance is small.
[0062] If desired, a charge controlling agent may be incorporated
into the fine support particles and/or low melting point substance
to improve transferability thereof to the image recording material.
Any charge controlling agent customarily employed in the field of
electrophotography may be used.
[0063] The image forming substance which includes a colorant and,
optionally, a binder resin may be a toner for use in, for example,
electrophotography, powder ink for solid ink jet recording, ink for
thermal transfer recording, ink for ordinary printing such as
letterpress printing or lithographic printing and other solid inks
such as crayon. The image recording material on which images are
formed with the above image forming substance may be, for example,
ordinary paper made of fibers and generally used with conventional
copying machines and printers, or a plastic film for overhead
projectors.
[0064] Description will be made of a toner which is a typical
example of the image forming substance.
[0065] The toner generally includes a colorant, a binder resin and
optional ingredients such as a charge controlling agent, a release
agent, a magnetic substance, a filler and a post treating
agent.
[0066] The binder resin may be any thermoplastic resin used for
conventional toners. Illustrative of suitable binder resins are a
styrene-acrylic copolymer resin, a styrene resin, a (meth)acrylic
resin, an olefin resin, a polyester resin, a polyamide resin, a
polycarbonate resin, a polyether resin, a polysulfone resin, an
epoxy resin, an urethane resin, a phenol resin, a urea resin,
copolymers thereof and mixtures thereof. The binder resin generally
has a number average molecular weight Mn of about 6,000 to 20,000
and a ratio Mw/Mn of the weight average molecular weight Mw to the
number average molecular weight Mn of about 2 to 100. The above
molecular weight and molecular weight distribution are, however,
not restrictive and may be changed as long as toner having desired
characteristics may be obtained.
[0067] A variety of types and colors of organic and inorganic
pigments and dyes conventionally used in the art are usable as a
colorant contained in the toner of the invention.
[0068] Examples of usable black pigments include carbon black,
cupric oxide, manganese dioxide, aniline black, activated carbon,
non-magnetic ferrite, magnetic ferrite and magnetite.
[0069] Examples of usable yellow pigments include chrome yellow,
zinc yellow, cadmium yellow, yellow oxide, mineral fast yellow,
nickel titanium yellow, NABLES YELLOW, NAPHTHOL YELLOW S, HANSA
YELLOW G, HANSA YELLOW 10G, benzidine yellow G, benzidine yellow
GR, quinoline yellow lake, permanent yellow NCG and tartrazine
lake.
[0070] Examples of usable orange pigments include chrome orange,
molybdenum orange, permanent orange GTR, pyrazolone orange, VULCAN
ORANGE, INDANTHRENE BRILLIANT ORANGE RK, benzidine orange G and
INDANTHRENE BRILLIANT ORANGE GK.
[0071] Examples of usable red pigments include iron oxide red,
cadmium red, red lead oxide, cadmium mercury sulfide, cadmium,
permanent red 4R, LITHOL RED, pyrazolone red, WATCHING RED, calcium
salt, lake red D, BRILLIANT CARMINE 6G, eosin lake, rhodamine lake
B, alizarin lake and BRILLIANT CARMINE 3B.
[0072] Examples of usable violet pigments include manganese violet,
fast violet R and methyl violet lake.
[0073] Examples of usable blue pigments include prussian blue,
cobalt blue, alkali blue lake, victoria blue lake, phthalocyanine
blue, metal-free phthalocyanine blue, phthalocyanine blue partial
chlorine compound, FAST SKY BLUE and INDANTHRENE BLUE BC.
[0074] Examples of usable green pigments include chrome green,
chrome oxide, pigment green B, malachite green lake and FANAL
YELLOW GREEN G.
[0075] Examples of usable white pigments include zinc white,
titanium oxide, antimony white and zinc sulfide.
[0076] Examples of usable extender pigments include powdery
barytes, barium carbonate, clay, silica, white carbon, talc and
alumina white.
[0077] As various types of dyes such as basic dyes, acid dyes,
disperse dyes and direct dyes may be usable. Examples of such dyes
include nigrosine, methylene blue, rose bengale, quinoline yellow
and ultramarine blue.
[0078] These colorants may be used alone or in combination of
plural types. The amount of the colorant is generally 1 to 20 parts
by weight, preferably, 2 to 10 parts by weight, per 100 parts by
weight of the binder resin of the toner for reasons of suitable
image density and fixing properties.
[0079] Various types and colors of pigments and dyes, as listed
below, are usable as the colorant of a transparent color toner.
[0080] Examples of usable yellow pigments include C.I.10316
(naphthol yellow S), C.I.11710 (HANSA YELLOW 10G), C.I.11660 (HANSA
YELLOW 5G), C.I.11670 (HANSA YELLOW 3G), C.I.11680 (HANSA YELLOW
G), C.I.11730 (HANSA YELLOW GR), C.I.11735 (HANSA YELLOW A),
C.I.11740 (HANSA YELLOW RN), C.I.12710 (HANSA YELLOW R), C.I.12720
(PIGMENT YELLOW L), C.I.21090 (benzidine yellow), C.I.21095
(benzidine yellow G), C.I.21100 (benzidine yellow GR), C.I.20040
(permanent yellow NCG), C.I.21220 (VULCAN FAST YELLOW 5) and
C.I.21135 (VULCAN FAST YELLOW R).
[0081] Examples of usable red pigments include C.I.12055 (STERLING
I), C.I.12075 (permanent orange), C.I.12175 (LITHOL FAST ORANGE
3GL), C.I.12305 (permanent orange GTR), C.I.11725 (HANSA YELLOW
3R), C.I.21165 (VULCAN FAST ORANGE GG), C.I.21110 (benzidine orange
G), C.I.12120 (permanent red 4R), C.I.1270 (PARA RED), C.I.12085
(FIRE RED), C.I.12315 (BRILLIANT FAST SCARLET), C.I.12310
(permanent red FR2), C.I.12335 (permanent red F4R), C.I.12440
(permanent red FRL), C.I.12460 (permanent red FRLL), C.I.12420
(permanent red F4RH), C.I.12450 (LIGHT FAST RED TONER B), C.I.12490
(permanent carmine FB) and C.I.15850 (BRILLIANT CARMINE 6B).
[0082] Examples of usable blue pigments include C.I.74100
(metal-free phthalocyanine blue), C1.74160 (phthalocyanine blue)
and C.I.74180 (FAST SKY BLUE).
[0083] These colorants for the transparent color toner may be used
alone or in combination of plural types. The amount of the colorant
is generally in the range of 1 to 10 parts by weight, preferably 2
to 5 parts by weight, per 100 parts by weight of the binder resin
of the toner for reasons of suitable color density and suitable
transparency.
[0084] As the release agent (anti-offset agent), there may be used
any known release agent used in the conventional toners. Examples
of suitable release agents include low molecular weight
polypropylene wax, low molecular weight polyethylene wax, low
molecular weight oxidized polypropylene wax, low molecular weight
oxidized polyethylene wax, candelilla wax, carnauba wax, rice wax,
montan wax and derivatives thereof, paraffin wax and derivatives
thereof, microcrystalline wax and derivatives thereof, sazol wax
and oxidized derivatives thereof, cured castor oil and derivatives
thereof, 1,2-hydroxystearic acid, higher fatty acid wax and higher
fatty acid ester wax.
[0085] These waxes may be used singly or in combination of two or
more. The amount of the release agent is generally in the range of
1 to 10 parts by weight, preferably 2 to 5 parts by weight, per 100
parts by weight of the binder resin contained in the toner, when
the toner image is fixed using an oil-less heat roll fixing device.
The amount of the release agent is not specifically limited when
fixation is carried out using other types of fixing device.
[0086] The magnetic substance may be metals such as aluminum,
cobalt, iron, lead, magnesium, zinc, nickel, antimony, beryllium,
bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten,
vanadium, alloys, mixtures, oxides and calcined products (ferrite)
of the above metals. The magnetic substance is generally used in an
amount of 1 to 80 parts by weight, preferably of 5 to 60 parts by
weight, per 100 parts by weight of the binder resin in the
toner.
[0087] As the charge control agent, there may be used any charge
control agent used in the conventional toners. Examples of
charge-control agent for a negative charge-toner include chromium
complex type azo dyes S-32, S-33, S-34, S-35, S-37, S-38, S-40
(Orient Kagaku Kogyo Co.); Aizen Spilon Black TRH, Aizen Spilon
Black BHH (Hodogaya Kagaku Co.); Kayaset Black T-22, Kayaset Black
004 (Nihon Kagaku Co.); Copper phthalocyanine dye S-39 (Orient
Kagaku Kogyo Co.); chrome complexes of salicylic acid E-81, E-82
(Orient Kagaku Kogyo Co.); zinc complex E-84 (Orient Kagaku Kogyo
Co.); aluminum complex E-86 (Orient Kagaku Kogyo Co.); calix arene
compounds and the like. Examples of a charge-control agent for a
positive charge-toner include Bontron N-01, Bontron P-51 (Orient
Kagaku Kogyo Co.), and imidazole compounds.
[0088] The post treating agent is used as an external additive to
be bound to surfaces of toner particles. Examples of the post
treating agent include carbides such as silicon carbide, boron
carbide, titanium carbide, zirconium carbide, hafnium carbide,
vanadium carbide, tantalum carbide, niobium carbide, tungsten
carbide, chromium carbide, molybdenum carbide, calcium carbide and
diamond carbon random; nitrides such as boron nitride, titanium
nitride and zirconium nitride; bromides such as zirconium bromide;
oxides such as titanium oxide, calcium oxide, magnesium oxide, zinc
oxide, copper oxide, aluminum oxide, silica and colloidal silica;
sulfides such as molybdenum disulfide; fluorides such as magnesium
fluoride and carbon fluoride; metal soaps such as aluminum
stearate, calcium stearate, zinc stearate and magnesium stearate;
minerals such as talc and bentonite; metals such as cobalt, iron,
nickel, aluminum, copper, lead, magnesium, tin, zinc, antimony,
beryllium, bismuth, cadmium, calcium, manganese, selenium, titan,
tungsten and vanadium; alloys of the above metals; polymer
particles, which are formed into particles by a wet polymerization
method such as an emulsion polymerization method, a soap-free
emulsion polymerization method and a non-aqueous dispersion
polymerization method, and a vapor phase method, such as styrene,
(metha)acrylic polymers, polyolefins, fluorine-containing
(metha)acrylic polymers, nitrogen-containing (metha)acrylic
polymers, epoxy resins, silicone resins, benzoguanamine resins,
melamine resin and copolymers thereof. These post treating agents
may be used singly or in combination. The amount of the post
treating agent is generally 0.01-5 parts by weight, preferably
0.1-3 parts by weight, per 100 parts by weight of the toner.
[0089] The toner may be prepared by any suitable known method such
as a grinding method; a wet method such as a spray dry method, a
granulation polymerization method (emulsion polymerization or
suspension polymerization) or an emulsion or dispersion granulation
method; or a microcapsule method. Specific examples of the method
include a mechanical method in which ingredients of the toner such
as a binder and a colorant are melt-kneaded, solidified, ground and
further processed with a hybridizer or a mechanofusion; a spray dry
method in which ingredients of the toner are dispersed in a
solution of a toner binder dissolved in a solvent, the dispersion
being subsequently spray dried; and a dispersion method in which an
organic solvent solution, emulsion or dispersion containing
ingredients of the toner such as a binder resin or a prepolymer
thereof and wax is dispersed in an aqueous medium with stirring,
preferably while applying shear forces to the wax, to form toner
particles which are subsequently separated and dried. The toner
generally has a particle size of 3 to 20 .mu.m, preferably 4 to 15
.mu.m, more preferably 6 to 12 .mu.m.
[0090] For depositing or fixing the binding force reducing
substance such as a low melting point substance to outer surfaces
of particles of the image forming substance such as a toner, the
binding force reducing substance (which may be supported by fine
support particles through binding to outer surfaces thereof or
through incorporation therewithin) and the image forming substance
particles are separately prepared and then mixed with each other
using a surface modifying device such as a hybridizer or an Ang
mill or a mixing device such as a Henschel mixer or a Hi-X mixer.
For incorporation of the binding force reducing substance into
particles of the image forming substance, the binding force
reducing substance is mixed with the ingredients of the image
forming substance (such as a colorant and a binder in the case of a
toner) and the mixture is then granulated into a desired method
such as a grinding method a wet method such as a spray dry method,
a granulation polymerization method (emulsion polymerization or
suspension polymerization), or an emulsion or dispersion
granulation method.
[0091] The binding force reducing substance may be supported to the
fine support particles by any method such as a surface modifying
method. One suitable method is as follows. The fine support
particles having hydrophilic groups such as carboxylic acid groups
are dispersed in an insoluble solvent such as toluene. The binding
force reducing substance having both hydrophilic groups and
hydrophobic (lipophilic) groups is then added to the dispersion and
the mixture is heated at 90-95.degree. C. with stirring so that the
binding force reducing substance is bound to the fine support
particles. The solvent is then removed from the mixture to leave
solids which are subsequently ground, if necessary.
[0092] An image formed on an image recording material using the
above-described image forming material may be removed by contacting
a stripping member under pressure with the image on the image
recording material while heating the image to reduce the image
binding force established between the image and the image recording
material. The image recording material is then peeled from the
stripping member so that the image is transferred from the image
recording material to the stripping member.
[0093] When the image has been formed on the image recording
material by fusing and fixing the image forming substance thereon
likewise in the case of a toner image, the heating under pressure
of the image is preferably at a temperature higher than the fixing
temperature for reasons of improved image removing efficiency
attributed to an increased possibility that the low melting point
substance (binding force reducing substance) is present at the
interface between the image and the recording material.
[0094] The stripping member may be in the form of a roller or a
film. The surface of the roller or film to which the image is
contacted may be made of a resin similar to the binder resin
contained in the image. Alternatively, an adhesive resin, a heat
resisting resin or a metal such as aluminum, copper, nickel, iron
or an alloy may be used as the surface material of the stripping
member.
[0095] Examples of the adhesive resin include protein adhesives
such as glue, gelatin, albumin and casein; carbohydrate adhesives
such as starch, cellulose and complex polysaccharide (Arabian gum,
tragacanth gum, etc.); thermoplastic adhesives such as vinyl
acetate polymers and copolymers, acrylic polymers and copolymers,
ethylene copolymers, polyamides, polyesters and polyurethanes;
rubber adhesives such as polychloroprene, nitrile rubber,
regenerated rubber, SBR and natural rubber; pressure-sensitive
adhesives such as rubber and acrylic polymers and copolymers;
thermoplastic resins which are the same as or which have good
affinity with the resin contained in the image forming substance,
such as vinyl acetate polymers and copolymers, (meth)acrylic
polymers and copolymers, olefin polymers and copolymers, styrene
polymers and copolymers, styrene-acrylic copolymers, polyamides,
polycarbonates, polysulfones, polyethers, epoxy resins, urea
resins, polyesters and polyurethanes; rubber adhesives such as
polychloroprene, nitrile rubber, regenerated rubber, SBR and
natural rubber; and titanium oxide-dispersed poly(ethylene
terephthalate). Films of polyether sulfone, polyether imide,
polysulfone, polyethylene terephthalate, aromatic polyamide or
polyether ether ketone may also be suitably used as the surface
material of the stripping member.
[0096] In a further embodiment, the material constituting the
surface of the stripping member contains the above-described
binding force reducing substance. In this case, an image formed on
an image recording material with an image binding force being
established between the image and the image recording material is
removed by contacting the surface of the stripping member under
pressure with the image on the image recording material while
heating the image to reduce the image binding force by the action
of the binding force reducing substance contained in the surface of
the stripping member, followed by peeling the image recording
material from the stripping member to transfer the image from the
image recording material to the stripping member. It is preferred
that the image formed on the image recording material be formed
from an image forming material of the type described in the
foregoing which contains a binding force reducing substance. As
described previously, the image preferably has a viscoelasticity of
10.sup.4 Pa to 10.sup.6 Pa at the time of the heating. Also, the
image binding force is desirably reduced to 2.0 kg/cm.sup.2 or less
by the heating. Further, the image preferably has been formed on
the image recording material by fusing and fixing the image forming
material thereon. The heating is preferably at a temperature higher
than the fixing temperature at which the image has been formed on
the image recording material.
[0097] It is further preferred that the surface of the stripping
member comprise the binding force reducing substance and a
thermoplastic resin which is preferably the same as or which has
good affinity with the resin contained in the image forming
substance, such as vinyl acetate polymers and copolymers,
(meth)acrylic polymers and copolymers, olefin polymers and
copolymers, styrene polymers and copolymers, styrene-acrylic
copolymers, polyamides, polycarbonates, polysulfones, polyethers,
epoxy resins, urea resins, polyesters and polyurethanes, since the
image on the image recording material shows good adhesion to the
stripping member because of the similarity of the resins and since
resin of the surface of the stripping member is prevented from
transferring to the non-image portion (background portion) of the
image recording material because of the presence of the binding
force reducing substance in the stripping surface. The amount of
the binding force reducing substance is generally 1-75% by weight,
preferably 5-20% by weight, based on a total weight of the binding
force reducing substance and the thermoplastic resin. It is
preferred that the stripping member have a surface layer which
contains the above binding force reducing substance and the
thermoplastic resin and which is provided on a support which is
resistant to heat and tension and has dimensional stability.
[0098] FIG. 1 depicts a device for removing an image of an image
forming material formed on an image recording material 1. The
device has a stripping member 10 which, in the illustrated case, is
an endless film supported by a drive roller 8, support rollers 9
and tension rollers 12 and 14. Disposed in parallel with the drive
roller 8 is a roller 11 defining therebetween a nip through which
the film (stripping member) 11 passes and runs upon driving of the
roller 8. The image recording material 1 bearing an image thereon
is fed to the nip from a feed tray 2 though feed rollers 3 and a
guide plate 4, so that the image on the image recording material 1
is contacted with the stripping member 10 under pressure. A heater
7 is disposed in the drive roller 8 for heating the image on the
recording material 1 during its contact with the stripping member
10 under pressure, thereby reducing the binding force established
between the image and the recording material 1 while providing an
adhesion strength between the stripping member 10 and the image
which adhesion strength is not smaller than the image binding
force. The recording material 1 is further driven by the roller 8
to be discharged from the nip and separated from the stripping
member LO so that the image is transferred from the image recording
material 1 to the stripping member 10. The image transferred to the
stripping member 10 is removed therefrom by a cleaning member such
as a roller, blade or brush. Designated as 13 is a temperatures
sensor electrically coupled to the heater 7 through a suitable
control device, so that the nip may be maintained at a desired
temperature. The recording material 1 from which the image has been
removed is collected and recycled to an image forming device 20 for
forming an image thereon.
[0099] In another preferred embodiment, there is provided an image
forming process which comprises forming an image on an image
recording material with an image binding force being established
between the image and the image recording material, wherein before
the image is formed, the above-described binding force reducing
substance is deposited on the inage recording material. The binding
force reducing substance reduces the image binding force when the
image is heated so that the image can be removed. Since the binding
force reducing substance and an image forming substance from which
the image is formed are stored separately from each other, storage
stability of the image forming substance is not adversely affected
by the binding force reducing substance. In addition, it is
possible to form images without using binding force reducing
substance if image removal is not intended.
[0100] The following examples will further illustrate the present
invention.
EXAMPLE 1
[0101] Toner (Imagio Toner Type 18 manufactured by Ricoh Company,
Ltd.) as an image forming substance and
C.sub.17H.sub.35PO.sub.3H.sub.2 powder having an average particle
diameter of 3 .mu.m as a binding force reducing substance were
mixed using a mill to obtain a developer (an image forming
material) containing 20% by weight of the binding force reducing
substance based on a total weight of the image forming substance
and the low melting point substance. Using the thus obtained
developer, a toner image having an image density of 1.2 was formed
on plain paper (PPC paper Type 6200 manufactured by Ricoh Company,
Ltd.) at a paper feed rate of about 30 mm/second. The temperature
of the toner image fixing roll was about 100.degree. C. The toner
image was evaluated for fixation by scratching the image bearing
paper with a nail. The fixation was rated as follows:
[0102] A: the image is not removed at all
[0103] B: part of the image remains unremoved
[0104] C: the image is completely removed
[0105] The results are shown in Table 1.
[0106] The image bearing paper was then charged on an image
removing device constructed as shown in FIG. 1. The image removing
device had a stripping member 10 which was an endless film having a
thickness of 100 .mu.m and made of a polyether ether ketone
(SUMILITE FS-1100C manufatured by Sumitomo Bakelite Inc.). The
image bearing paper was passed through the nip between the rolls 8
and 11 at a feed rate of about 30 mm/second to contact the image
with the stripping member 10 while maintaining the driving roll 8
at a temperature of about 110.degree. C. and to remove the image
from the paper. The resulting paper was evaluated for removability
of the image with naked eyes. The removability was rated as
follows:
[0107] 5: the image is entirely removed
[0108] 4: the image is almost entirely removed with only a slight
portion thereof remaining unremoved
[0109] 3: a part of the image remains unremoved
[0110] 2: a significant portion of the image remains unremoved
[0111] 1: the image almost entirely remains unremoved The results
are shown in Table 1.
EXAMPLE 2
[0112] Polyacrylic acid particles (as fine support particles) were
dispersed in toluene. A binding force reducing substance
(C.sub.17H.sub.35PO.sub.3H.sub.2 powder) was then added to the
dispersion and the mixture was heated at 90-95.degree. C. with
stirring so that the C.sub.17H.sub.35PO.sub.3H.sub.2 was bound to
the polyacrylic acid particles. The toluene was then removed from
the mixture to leave solids which were subsequently milled to
obtain an external additive powder having an average particle size
of 3 .mu.m. The thus obtained external additive was mixed with
toner (Imagio Toner Type 18 manufactured by Ricoh Company, Ltd.)
using a mill to obtain a developer having a
C.sub.17H.sub.35PO.sub.3H.sub.2 content of 4% by weight and a
polyacrylic acid content of 1% by weight based on a total weight of
the toner and the external additive. Using the thus obtained
developer, an image was formed on a paper and the image was removed
from the paper in the same manner as described in Example 1. The
fixation and removability are shown in Table 1.
EXAMPLE 3
[0113] Example 2 was repeated in the same manner as described
except that the amount of the external additive was increased so
that the developer had a C.sub.17H.sub.35PO.sub.3H.sub.2 content of
8% by weight and a polyacrylic acid content of 2% by weight based
on a total weight of the toner and the external additive. The
results are shown in Table 1.
EXAMPLE 4
[0114] Example 2 was repeated in the same manner as described
except that the amount of the external additive was increased so
that the developer had a C.sub.17H.sub.35PO.sub.3H.sub.2 content of
16% by weight and a polyacrylic acid content of 4% by weight based
on a total weight of the toner and the external additive. The
results are shown in Table 1. Further, the image was found to have
a binding force at room temperature of 1.0 kg/cm.sup.2, a binding
force at 110.degree. C. of 0.7 kg/cm.sup.2 and a viscoelasticity at
110.degree. C. of 10.sup.4 Pa to 10.sup.5 Pa.
EXAMPLES 5
[0115] Example 2 was repeated in the same manner as described
except that the amount of the external additive was increased so
that the developer had a C.sub.17H.sub.35PO.sub.3H.sub.2 content of
32% by weight and a polyacrylic acid content of 8% by weight based
on a total weight of the toner and the external additive. The
results are shown in Table 1.
EXAMPLES 6 TO 9
[0116] Examples 2 to 5 were repeated in the same manner as
described except that polyacrylic acid particles were replaced by
ethylene-methyl methacrylic acid (MMA) copolymer having an MMA
content of 15 wt %. The results are summarized in Table 1.
EXAMPLE 10
[0117] Porous silica particles (as fine support particles) were
dispersed in toluene. A binding force reducing substance
(C.sub.17H.sub.35PO.sub.3H- .sub.2 powder) was then added to the
dispersion and the mixture was heated at 90-95.degree. C. with
stirring so that the C.sub.17H.sub.35PO.sub.3H.s- ub.2 was included
in the silica particles. The toluene was then removed from the
mixture to obtain an external additive powder having an average
particle size of 3 .mu.m. The thus obtained external additive was
mixed with toner (Imagio Toner Type 18 manufactured by Ricoh
Company, Ltd.) using a mill to obtain a developer having a
C.sub.17H.sub.35PO.sub.3H.sub- .2 content of 2.5% by weight and a
silica content of 2.5% by weight based on a total weight of the
toner and the external additive. Using the thus obtained developer,
an image was formed on a paper and the image was removed from the
paper in the same manner as described in Example 1. The fixation
and removability are shown in Table 1.
EXAMPLES 11 TO 13
[0118] Example 10 repeated in the same manner as described except
that the amounts of C.sub.17H.sub.35PO.sub.3H.sub.2 and silica were
changed to obtain developers having C.sub.17H.sub.35PO.sub.3H.sub.2
and silica contents of each 5% by weight (Example 11), 10% by
weight (Example 12) and 20% by weight (Example 13), based on a
total weight of the toner and the external additive. The fixation
and removability are shown in Table 1.
[0119] The softening points of the binding force reducing
substances used in Examples are as follows:
[0120] C.sub.17H.sub.35PO.sub.3H.sub.2: 96.degree. C.
[0121] C.sub.16H.sub.32(OH).sub.2: 72-74.degree. C.
[0122] C.sub.21H.sub.43COOH: 81.degree. C.
[0123] C.sub.18H.sub.37NH.sub.2: 50-52
[0124] (C.sub.18H.sub.37O).sub.2PO.sub.2H: 79-81.degree. C.
[0125] (OH).sub.3BzCO.sub.2C.sub.18H.sub.37: 103-104.degree. C.
[0126] carnauba wax: 80-90.degree. C.
1 TABLE 1 Binding force reducing Fine supporting substance
particles Amount Amount Example Compound (wt %) Compound (wt %)
Fixation Removability 1 C.sub.17H.sub.35--PO.sub.3H.sub.2 20 -- --
A 4 2 C.sub.17H.sub.35--PO.sub.3H.sub.2 4 Polyacrylic 1 A 3 acid 3
C.sub.17H.sub.35--PO.sub.3H.sub.2 8 Polyacrylic 2 A 4 acid 4
C.sub.17H.sub.35--PO.sub.3H.sub.2 16 Polyacrylic 4 A 5 acid 5
C.sub.17H.sub.35--PO.sub.3H.sub.2 32 Polyacrylic 8 B 5 acid 6
C.sub.17H.sub.35--PO.sub.3H.sub.2 4 Ethylene- 1 A 3 MMA copolymer 7
C.sub.17H.sub.35--PO.sub.3H.sub.2 8 Ethylene- 2 A 4 MMA copolymer 8
C.sub.17H.sub.35--PO.sub.3H.sub.2 16 Ethylene- 4 A 5 MMA copolymer
9 C.sub.17H.sub.35--PO.sub.3H.sub.2 32 Ethylene- 8 B 5 MMA
copolymer 10 C.sub.17H.sub.35--PO.sub.3H- .sub.2 2.5 Porous 2.5 A 4
silica 11 C.sub.17H.sub.35--PO.sub.3H.sub.2 5 Porous 5 A 5 silica
12 C.sub.17H.sub.35--PO.sub.3H.sub.2 10 Porous 10 A 5 silica 13
C.sub.17H.sub.35--PO.sub.3H.sub.2 20 Porous 20 B 5 silica
EXAMPLE 14
[0127] Example 4 was repeated in the same manner as described
except that a diol (C.sub.16C.sub.32(OH).sub.2) was substituted for
C.sub.17H.sub.35PO.sub.3H.sub.2. The results are shown in Table 2.
The image was found to have a binding force at room temperature of
2.0 kg/cm.sup.2 and a binding force at 110.degree. C. of 1.4
kg/cm.sup.2.
EXAMPLE 15
[0128] Example 4 was repeated in the same manner as described
except that a carboxylic acid (C.sub.21H.sub.43--COOH) was
substituted for C.sub.17H.sub.35PO.sub.3H.sub.2. The results are
shown in Table 2. The image was found to have a binding force at
room temperature of 5 kg/cm.sup.2 or more and a binding force at
110.degree. C. of 2 kg/cm.sup.2 or more, A significant portion of
the image remained unremoved after the image removing
treatment.
EXAMPLE 16
[0129] Example 4 was repeated in the same manner as described
except that an amine (C.sub.18H.sub.37NH.sub.2) was substituted for
C.sub.17H.sub.35PO.sub.3H.sub.2. The results are shown in Table 2.
The image was found to have a binding force at room temperature of
5 kg/cm.sup.2 or more and a binding force at 110.degree. C. of 2
kg/cm.sup.2 or more. A significant portion of the image remained
unremoved after the image removing treatment.
EXAMPLE 17
[0130] Example 3 was repeated in the same manner as described
except that the stripping member 10 had a surface layer (thickness:
about 3 .mu.m) formed of the developer of Example 3. Namely, the
surface layer of the stripping member contained the binder of the
toner and the C.sub.17H.sub.35PO.sub.3H.sub.2. The results are
shown in Table 2.
EXAMPLE 18
[0131] Example 4 repeated in the same manner as described except
that the removal of the image was performed at a roll temperature
of 120.degree. C. The results are shown in Table 2. The image was
found to have a viscoelasticity at 120.degree. C. of less than
10.sup.4 Pa. A part of the image remained unremoved after the image
removing treatment.
EXAMPLE 19
[0132] Example 4 was repeated in the same manner as described
except that a phosphinic acid ((C.sub.17H.sub.37O).sub.2PO.sub.2H)
was substituted for C.sub.17H.sub.35PO.sub.3H.sub.2. The results
are shown in Table 2. It was confirmed that the external additive
(particles of polyacrylic acid to which the phosphinic acid was
bound) did not aggregate when allowed to stand for 100 hours in a
chamber at 30.degree. C. and a relative humidity of 90%. On the
other hand, polyacrylic acid particles without the phosphinic acid
formed aggregates when tested in the same manner as above.
EXAMPLE 20
[0133] Example 4 was repeated in the same manner as described
except that an aromatic ester
((OH).sub.3BzCO.sub.2C.sub.18H.sub.37; Bz designates a benzene
nucleus) was substituted for C.sub.17H.sub.35PO.sub.3H.sub.2. The
results are shown in Table 2. It was confirmed that the external
additive (particles of polyacrylic acid to which the aromatic ester
was bound) did not aggregate when allowed to stand for 100 hours in
a chamber at 30.degree. C. and a relative humidity of 90%.
EXAMPLE 21
[0134] Example 4 was repeated in the same manner as described
except that the external additive had an average particle diameter
of 10 .mu.m. The results are shown in Table 2.
EXAMPLE 22
[0135] Example 4 was repeated in the same manner as described
except that the external additive had an average particle diameter
of 20 .mu.m. The fixed image was partly removed by scratching with
a nail.
EXAMPLE 23
[0136] Example 1 was repeated in the same manner as described
except that the amount of the C.sub.17H.sub.35PO.sub.3H.sub.2 was
increased so that the developer had a
C.sub.17H.sub.35PO.sub.3H.sub.12 content of 40% by weigh based on a
total weight of the toner and the C.sub.17H.sub.35PO.sub.3H.sub.2.
The results are shown in Table 2.
COMPARATIVE EXAMPLE 1
[0137] Example 1 was repeated in the same manner as described
except that the toner was used by itself for the formation of
image. Namely, C.sub.17H.sub.35PO.sub.3H.sub.2 was not used at all.
The results are shown in Table 2.
COMPARATIVE EXAMPLE 2
[0138] A toner having the same composition as that used in Example
1 except that carnauba wax was additionally contained in an amount
of 80% by weight was prepared. Using the wax-containing toner,
image formation and removal were carried out in the same manner as
described in Example 1. The results are shown in Table 2.
COMPARATIVE EXAMPLE 3
[0139] Comparative Example 2 was repeated in the same manner as
described except that the amount of the carnauba wax was reduced to
60% by weight. The results are shown in Table 2.
COMPARATIVE EXAMPLE 4
[0140] A toner having the same composition as that used in Example
5 except that the binding force reducing substance was not used at
all was prepared. Using the resulting toner, image formation and
removal were carried out in the same manner as described in Example
1. The results are shown in Table 2.
COMPARATIVE EXAMPLE 5
[0141] A toner having the same composition as that used in Example
9 except that the binding force reducing substance was not used at
all was prepared. Using the resulting toner, image formation and
removal were carried out in the same manner as described in Example
1. The results are shown in Table 2.
COMPARATIVE EXAMPLE 6
[0142] A toner having the same composition as that used in Example
12 except that the binding force reducing substance was not used at
all was prepared. Using the resulting toner, image formation and
removal were carried out in the same manner as described in Example
1. The results are shown in Table 2.
[0143] The invention may be embodied in other specific forms
without departing from the spirit or essential characteristics
thereof. The present embodiments are therefore to be considered in
all respects as illustrative and not restrictive, the scope of the
invention being indicated by the appended claims rather than by the
foregoing description, and all the changes which come within the
meaning and range of equivalency of the claims are therefore
intended to be embraced therein.
[0144] The teachings of Japanese Patent Application No.
2001-232576, filed Jul. 31, 2001, inclusive of the specification,
claims and drawing, are hereby incorporated by reference
herein.
2 TABLE 2 Binding force reducing Fine supporting substance
particles Amount Amount Example Compound (wt %) Compound (wt %)
Fixation Removability 14 C.sub.16H.sub.32--(OH).sub.2 16
Polyacrylic 4 A 4 acid 15 C.sub.21H.sub.43--COOH 16 Polyacrylic 4 A
2 acid 16 C.sub.18H.sub.37--NH.sub.2 16 Polyacrylic 4 A 2 acid 17
C.sub.17H.sub.35--PO.sub.3H.sub.2 8 Polyacrylic 2 A 5 acid 18
C.sub.17H.sub.35--PO.sub.3H.sub.2 16 Polyacrylic 4 A 3 acid 19
(C.sub.18H.sub.37O).sub.2--PO.sub.2H 16 Polyacrylic 4 A 4 acid 20
(OH).sub.3BZ--CO.sub.2C.sub.18H.sub.37 16 Polyacrylic 4 A 3 acid 21
C.sub.17H.sub.35--PO.sub.3H.su- b.2 16 Polyacrylic 4 A 5 acid 22
C.sub.17H.sub.35--PO.sub- .3H.sub.2 16 Polyacrylic 4 B 5 acid 23
C.sub.17H.sub.35--PO.sub.3H.sub.2 40 -- -- B 5 Comp. 1 -- -- -- --
A 1 Comp. 2 carnauba 80 -- -- A 1 wax Comp. 3 carnauba 60 -- -- A 1
wax Comp. 4 -- -- Polyacrylic 8 A 1 acid Comp. 5 -- -- Ethylene- 8
A 1 MMA copolymer Comp. 6 -- -- Porus 10 A 1 silica
* * * * *