Source: http://www.patentsencyclopedia.com/app/20080226998
Timestamp: 2017-03-28 21:43:00
Document Index: 15129509

Matched Legal Cases: ['in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine', 'in fine']

FINE ORGANIC SILICONE PARTICLE FOR LATENT ELECTROSTATIC IMAGE DEVELOPING TONERS, EXTERNAL ADDITIVE FOR TONERS, TONER FOR DEVELOPING LATENT ELECTROSTATIC IMAGE, AND TWO-COMPONENT DEVELOPER - Patent application
Patent application title: FINE ORGANIC SILICONE PARTICLE FOR LATENT ELECTROSTATIC IMAGE DEVELOPING TONERS, EXTERNAL ADDITIVE FOR TONERS, TONER FOR DEVELOPING LATENT ELECTROSTATIC IMAGE, AND TWO-COMPONENT DEVELOPER
Masayuki Ishii (Numazu-Shi, JP)
Ryota Inoue (Mishima-Shi, JP)
Yoshihiro Moriya (Numazu-Shi, JP)
Shingo Sakashita (Numazu-Shi, JP)
Patent application number: 20080226998
The present invention provides an organic silicone fine particle for
latent electrostatic image developing toners, wherein the organic
silicone fine particle has a volume average particle diameter of 0.05
μm to 6.0 μm which is obtained by measurement based on Coulter
principle, and has a hemispherical polysiloxane cross-linked structure.
By mixing an appropriate amount of an organic silicone resin particle
formed in a deformed shape (a hemispherical shape) in a toner or
developer, the present invention prevents movement of the organic
silicone resin particle from surface functional sites, the movement
caused by a phenomenon such as detachment thereof from a toner surface or
rolling movement on the toner surface, by the effect of its shape, and
makes it possible to effectively achieve the expected function.Claims:
1. An organic fine particle for latent electrostatic image developing
toners,wherein the organic fine particle has a volume average particle
diameter of 0.05 μm to 6.0 μm which is obtained by measurement
based on Coulter principle, and has a hemispherical shape.
2. An organic silicone fine particle for latent electrostatic image
developing toners,wherein the organic silicone fine particle has a volume
average particle diameter of 0.05 μm to 6.0 μm which is obtained by
measurement based on Coulter principle, and has a hemispherical
polysiloxane cross-linked structure.
3. The organic silicone fine particle according to claim 2, wherein the
polysiloxane cross-linked structure constituting the organic silicone
fine particle is composed of two or more siloxane units selected from
siloxane units each expressed by the following Formula 1, and has an
average siloxane unit expressed by the following Formula 2,R1mSiO(4-m)/2
Formula 1R2nSiO(4-n)/2 Formula 2where R1 and R2 are respectively an
organic group having a carbon atom directly bound to an Si atom, "m" is
an integer of 0 to 3, "n" is from 0.40 to 0.77.
4. The organic silicone fine particle according to claim 3, wherein the
polysiloxane cross-linked structure comprises a first siloxane unit in
the case where "m" in the Formula 1 is 0 and a second siloxane unit in
the case where "m" in the Formula 1 is 1, and a molar ratio of [the first
siloxane unit]/[the second siloxane unit] is 23/77 to 40/60.
5. The organic silicone fine particle according to claim 3, wherein R1 in
the Formula 1 and R2 in the Formula 2 are respectively a methyl group.
6. An external additive for the latent electrostatic image developing
toners, wherein the latent electrostatic image developing toners contain
at least a colored particle and an external additive; the colored
particle comprises at least a binder resin, a colorant, and a releasing
agent; the external additive is an organic silicone fine particle having
a volume average particle diameter of 0.05 μm to 6.0 μm which is
obtained by measurement based on Coulter principle and has a hemispheric
7. A toner for developing latent electrostatic images, comprising:a
colored particle, andan external additive,wherein the colored particle
comprises at least a binder resin, a colorant, and a releasing agent; the
external additive is an organic silicone fine particle having a volume
measurement based on Coulter principle and has a hemispheric polysiloxane
cross-linked structure.
8. The toner for developing latent electrostatic images according to claim
7, further comprising one or more other external additives.
9. The toner for developing latent electrostatic images according to claim
8, wherein the one or more other external additives comprise at least one
external additive having a B.E.T. specific surface area in the range of
20 m2/g to 300 m2/g.
10. The toner for developing latent electrostatic images according to
claim 8, wherein the one or more other external additives are selected
from the group consisting of silica, titanium compounds, alumina, cerium
oxides, calcium carbonates, magnesium carbonates, calcium phosphates,
fluorine-containing resin fine particles, silica-containing resin fine
particles, and nitrogen-containing resin fine particles.
11. The toner for developing latent electrostatic images according to
claim 10, wherein the titanium compound is obtained by reacting a part of
or all of TiO(OH)2 produced by a wet system with any one of a silane
compound and a silicone oil.
12. The toner for developing latent electrostatic images according to
claim 10, wherein the titanium compound has a specific gravity of 2.8 to
13. The toner for developing latent electrostatic images according to
claim 7, wherein the colored particle is obtained by dissolving or
dispersing in an organic solvent a toner composition containing a toner
binder resin composed of a compound having an active hydrogen group and a
modified polyester resin capable of reacting with an active hydrogen
group, then dispersing into droplets the resulting solution or dispersion
in an aqueous medium containing a resin fine particle, reacting the
compound having an active hydrogen group with the modified polyester
resin capable of reacting with an active hydrogen group, and finally
removing the solvent from the dispersion fluid thus obtained.
14. The toner for developing latent electrostatic images according to
claim 7, wherein the colored particle is obtained by a
melt-kneading/pulverization method.
15. A developer for developing latent electrostatic images, comprising;a
toner for developing latent electrostatic images, anda carrier,wherein
the toner is a toner for developing latent electrostatic images, which
comprises a colored particle and an external additive, the colored
16. An image forming method, comprising:developing a latent electrostatic
image formed on a latent image bearing member using a toner to form a
toner image, andtransferring the toner image onto a transfer material to
form a transferred image,wherein the toner is a toner for developing
latent electrostatic images, which comprises a colored particle and an
external additive; the colored particle comprises at least a binder
resin, a colorant, and a releasing agent; the external additive is an
organic silicone fine particle having a volume average particle diameter
of 0.05 μm to 6.0 μm which is obtained by measurement based on
Coulter principle and has a hemispheric polysiloxane cross-linked
17. An image forming method, comprising:developing a latent electrostatic
form a transferred image,wherein the developer used in the developing
comprises a toner and a carrier; the toner is a toner for developing
18. A process cartridge detachably mounted to a main body of an image
forming apparatus, comprising:a photoconductor, anda developing unit,the
photoconductor and the developing unit being integrated as a unit,the
process cartridge may further comprising one image processing unit
selected from a charging unit, a transfer unit, a cleaning unit, and a
charge eliminating unit,wherein the developing unit holds a toner; the
toner is a toner for developing latent electrostatic images, which
comprises a colored particle and an external additive; the colored
polysiloxane cross-linked structure.Description:
[0002]The present invention relates to a fine organic silicone particle
for latent electrostatic image developing toners, an external additive
for toners, a latent electrostatic image developing toner, a
two-component developer, and a developing device using them.
[0004]It has been proposed that the use of fine inorganic particles with
large diameters is effective in improving toner's developability,
transferability and cleanability, as well as in preventing embedment of
external additive in toner particles that is caused by various stresses
on the toner particles. Also disclosed is a technology in which organic
fine particles that are 50 nm to 200 nm in diameter are added to toner in
order to provide an effective spacer function. When an external additive
is mixed with toner using a mixer, it is necessary to dissociate
aggregates of the external additive and toner for deposition of the
external additive onto the toner surface. However, this process causes a
situation where some particles of external additive occasionally remains
free without adhering to the toner surface, or where some particles of
external additive bonded to the toner surface to some degree are detached
from the toner surface by stress, a friction, etc. in the developing
device. The above free external additive is often recognized to move to
the photoconductor with toner at the time of toner development on a
photoconductor surface, remaining on the photoconductor surface even
after transfer of the developed image and adhering to the photoconductor
surface without be removed by cleaning process. When free external
additive particles are deposited onto the photoconductor surface, they
become a frequent cause of image quality defect on a copy (filming, etc.)
or scratches on the photoconductor, thereby reducing the lifetime of the
photoconductor. Further this also causes contamination of the copier when
the free external additive drops out of the developing device upon
development. Moreover, the free external additive adheres to carrier
surface in a developer and inhibits transportation of electric charges
between toner and carrier, which may result in reduced toner charge
[0005]Japanese Patent Application Laid-Open (JP-A) No. 06-266152 discloses
using as external additives fine inorganic particles having a
volume-average particle diameter of 30 nm to 150 nm and organic fine
particles having a volume-average particle diameter of 50 nm to 200 nm
made of high-melting point resin with a flow-starting temperature of
200° C. or more in order to reduce the degree of embedment of
external additive into toner particles. However, it is technically
difficult to effect uniform surface treatment on such two different types
of fine particles, and it is also difficult to strike a balance between
prevention of embedment and prevention of detachment of external additive
because the two external additives have different affinities for the
toner binder. Meanwhile, JP-A No. 07-28276 discloses using as external
additives small diameter-inorganic particles in combination with large
diameter-inorganic particles, such as particles of silica, titanic oxide
or alumina that are hydrophobized by treatment with a silane coupling
agent. However, sufficient external additive functions have not yet been
achieved by this technology, which is due in part to the fact that
external additive particles generally offer a broad particle size
distribution. JP-A No. 09-319134 discloses adding, among inorganic
external additives with a relatively large particle diameter and organic
external additives with a relatively small particle diameter, organic and
inorganic external additives each having a number-average particle
diameter of 0.05 μm to 0.5 μm in such amounts that the toner
turbidity is 10 to 50. However, this technique is not directly associated
with prevention of embedment of external additive in toner particles and
with prevention of detachment of the external additive from the toner
particles. Furthermore, JP-A No. 10-312089 discloses, in order to
increase the toner charge amount, using as an external additive silica
that is hydrophobized by treatment with a silicone oil and that has a
primary particle average diameter of 30 nm to 100 nm in combination with
a zinc salt of benzylic acid derivative as a charge controlling agent.
This technique is not also directly associated with prevention of
embedment of external additive in toner particles and prevention of
detachment of the external additive from the toner particles.
[0006]To solve the above-described problems pertinent in the art, by
mixing an appropriate amount of deformed (hemispherical shape) organic
silicone resin particles in a toner or developer, the present invention
prevents, by means of their shape effect, the organic silicone resin
particles from detaching from toner surface or from moving away from the
surface function site due to rolling movement on the toner surface,
thereby allowing the organic resin particles to effectively offer their
expected functions. Conventional deformed shapes directed to achieve this
effect have been randomly-deformed, non-spherical shapes such as those
obtained by pulverization; thus, it has been difficult to establish a
reasonable trade-off between flowability and expected function, both of
which are associated with their complex shape. In addition, deformation
by means of pulverization has been insufficient in terms of shape
[0007]The above problems are solved by the present invention as follows.
[0008](1) An organic fine particle for latent electrostatic image
developing toners, wherein the organic fine particle has a volume average
particle diameter of 0.05 μm to 6.0 μm which is obtained by
measurement based on Coulter principle, and has a hemispherical shape.
[0009](2) An organic silicone fine particle for latent electrostatic
image developing toners, wherein the organic silicone fine particle has a
volume average particle diameter of 0.05 μm to 6.0 μm which is
obtained by measurement based on Coulter principle, and has a
hemispherical polysiloxane cross-linked structure. [0010](3) The organic
silicone fine particle according to the item (2), wherein the
average siloxane unit expressed by the following Formula 2,
[0010]R1mSiO(4-m)/2 Formula 1
R2nSiO(4-n)/2 Formula 2
[0011]where R1 and R2 are respectively an organic group having a carbon
atom directly bound to an Si atom, "m" is an integer of 0 to 3, "n" is
from 0.40 to 0.77. [0012](4) The organic silicone fine particle according
to the item (3), wherein the polysiloxane cross-linked structure contains
a first siloxane unit in the case where "m" in the Formula 1 is 0 and a
second siloxane unit in the case where "m" in the Formula 1 is 1, and a
molar ratio of [the first siloxane unit]/[the second siloxane unit] is
23/77 to 40/60. [0013](5) The organic silicone fine particle according to
the item (3), wherein R1 in the Formula 1 and R2 in the Formula 2 are
respectively a methyl group. [0014](6) An external additive for the
latent electrostatic image developing toners, containing a colored
particle, and an external additive, wherein the colored particle contains
at least a binder resin, a colorant, and a releasing agent, the external
additive is an organic silicone fine particle having a volume average
cross-linked structure. [0015](7) A toner for developing latent
electrostatic images, containing a colored particle, and an external
additive, wherein the colored particle contains at least a binder resin,
a colorant, and a releasing agent, the external additive is an organic
silicone fine particle having a volume average particle diameter of 0.05
principle and has a hemispheric polysiloxane cross-linked structure.
[0016](8) The toner for developing latent electrostatic images according
to the item (7), further containing one or more other external additives.
[0017](9) The toner for developing latent electrostatic images according
to the item (8), wherein the one or more other external additives contain
at least one external additive having a B.E.T. specific surface area in
the range of 20 m2/g to 300 m2/g. [0018](10) The toner for
developing latent electrostatic images according to the item (8), wherein
the one or more other external additives are selected from the group
consisting of silica, titanium compounds, alumina, cerium oxides, calcium
carbonates, magnesium carbonates, calcium phosphates, fluorine-containing
resin fine particles, silica-containing resin fine particles, and
nitrogen-containing resin fine particles. [0019](11) The toner for
developing latent electrostatic images according to the item (10),
wherein the titanium compound is obtained by reacting a part of or all of
TiO(OH)2 produced by a wet system with any one of a silane compound
and a silicone oil. [0020](12) The toner for developing latent
electrostatic images according to the item (10), wherein the titanium
compound has a specific gravity of 2.8 to 3.6. [0021](13) The toner for
developing latent electrostatic images according to the item (7), wherein
the colored particle is obtained by dissolving or dispersing in an
organic solvent a toner composition containing a toner binder resin
composed of a compound having an active hydrogen group and a modified
polyester resin capable of reacting with an active hydrogen group, then
dispersing into droplets the resulting solution or dispersion in an
aqueous medium containing a resin fine particle, reacting the compound
having an active hydrogen group with the modified polyester resin capable
of reacting with an active hydrogen group, and finally removing the
solvent from the dispersion fluid thus obtained. [0022](14) The toner for
the colored particle is obtained by a melt-kneading/pulverization method.
[0023](15) A developer for developing latent electrostatic images,
containing a toner for developing latent electrostatic images, and a
carrier, wherein the toner is a toner for developing latent electrostatic
images, which contains a colored particle and an external additive, the
colored particle contains at least a binder resin, a colorant, and a
releasing agent, the external additive is an organic silicone fine
particle having a volume average particle diameter of 0.05 μm to 6.0
μm which is obtained by measurement based on Coulter principle and has
a hemispheric polysiloxane cross-linked structure. [0024](16) An image
forming method, including developing a latent electrostatic image formed
on a latent image bearing member using a toner to form a toner image, and
transferring the toner image onto a transfer material to form a
transferred image, wherein the toner is a toner for developing latent
electrostatic images, which contains a colored particle and an external
additive, the colored particle contains at least a binder resin, a
colorant, and a releasing agent, the external additive is an organic
[0025](17) An image forming method, including developing a latent
electrostatic image formed on a latent image bearing member using a
developer to form a toner image, and transferring the toner image onto a
transfer material to form a transferred image, wherein the developer used
in the developing contains a toner and a carrier; the toner is a toner
for developing latent electrostatic images, which contains a colored
particle and an external additive; the colored particle contains at least
a binder resin, a colorant, and a releasing agent; the external additive
is an organic silicone fine particle having a volume average particle
based on Coulter principle and has a hemispheric polysiloxane
cross-linked structure. [0026](18) A process cartridge detachably mounted
to a main body of an image forming apparatus, having a photoconductor,
and a developing unit, the photoconductor and the developing unit being
integrated as a unit, the process cartridge may further having one image
processing unit selected from a charging unit, a transfer unit, a
cleaning unit, and a charge eliminating unit, wherein the developing unit
holds a toner; the toner is a toner for developing latent electrostatic
images, which contains a colored particle and an external additive; the
releasing agent; the external additive is an organic silicone fine
a hemispheric polysiloxane cross-linked structure.
[0027]A hemispheric organic silicone resin particle according to the
present invention tends to adhere to a toner with its flat surface
directed to the bonding surface and with its spherical surface directed
outward because of its shape and structure, therefore occurrence of
rolling movement on a toner surface due to an environmental stress is
less frequent in this hemispheric organic silicone resin particle than in
a conventional spherical resin particle, and by directing the spherical
surface outward it became possible for the hemispheric organic silicone
resin particle to provide a toner flowability equal or more to that
provided by a spherical resin particle.
[0028]When some particles of the hemispheric organic silicone resin
particle adhere to a toner with their spherical surfaces directed to the
toner surface in an early period of addition, the direction of the
particles to a toner surface is easily changed to a more stable direction
with their flat surfaces directed to the toner surface due to an
environmental stress, which achieves high adhesion of the hemispheric
organic silicone resin particle to a toner surface that could not be
achieved by a conventional resin particle and solves, at the same time, a
problem of fixing inhibition caused by adding an inorganic external
additive such as silica to a toner. In addition, it is possible to use
the organic silicone resin particle as an additive into a toner particle
in a toner manufacturing process.
[0029]FIG. 1 illustrates an example of a process cartridge of the present
[0030]FIG. 2 illustrates an example of an image forming apparatus used in
[0031]FIG. 3 illustrates another example of an image forming apparatus
[0032]FIG. 4 illustrates still another example of an image forming
apparatus used in the present invention.
[0033]The binder resin contained in the colored particles according to the
present invention is not particularly limited, can be appropriately
selected from those known publicly, and includes, for example,
homopolymers and copolymers of styrenes such as styrene and
chlorostyrene; monoolefins such as ethylene, propylene, butylene, and
isoprene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl
benzoate, and vinyl butyrate; α-methylene aliphatic monocarboxylate
esters such as methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl
acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl
methacrylate, butyl methacrylate, and dodecyl methacrylate; vinyl ethers
such as vinyl methyl ether, vinyl ethyl ether, and vinyl butyl ether; and
vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl
isopropenyl ketone.
[0034]The particularly representative binder resins include, for example,
polystyrene resins, polyester resins, styrene-acrylic acid alkyl
copolymers, styrene-methacrylic acid alkyl copolymers,
styrene-acrylonitrile copolymers, styrene-butadiene copolymers,
styrene-maleic acid anhydrate copolymers, polyethylene resins, and
polypropylene resins. These may be used alone or in combination of two or
[0035]Among them, polyester resins are preferable, and urea-modified
polyester resins are more preferable, and the combination of the
urea-modified polyester resin and an unmodified polyester resin is the
[0036]The colorant is not particularly limited and can be appropriately
selected from publicly known dyes and pigments depending on the purpose.
For example, carbon black, nigrosine dyes, iron black, naphthol yellow S,
hanza yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, yellow
ocher, chrome yellow, titanium yellow, polyazo yellow, oil yellow, hanza
yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR),
permanent yellow (NCG), Balkan fast yellow (5G, R), tartrazine lake,
quinoline yellow lake, anthrazane yellow BGL, isoindolinone yellow,
colcothar, red lead, lead vermillion, cadmium red, cadmium mercury red,
antimony vermillion, permanent red 4R, parared, faicer red,
parachloroorthonitroaniline red, lithol fast scarlet G, brilliant fast
scarlet, brilliant carmine BS, permanent red (F2R, F4R, FRL, FRLL, is
F4RH), fast scarlet VD, Balkan 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, alizarin lake, thioindigo red B, thioindigo
maroon, oil red, quinacridone red, pyrazolone red, polyazo red, chrome
vermilion, benzidine orange, perinone orange, oil orange, cobalt blue,
cerulean blue, alkali blue lake, peacock blue lake, Victoria blue lake,
non-metallic phthalocyanine blue, phthalocyanine blue, fast sky blue,
indanthrene blue (RS, BC), indigo, ultramarine blue, Prussian blue,
zinc green, chromium oxide, pyridian, emerald green, pigment green B,
phthalocyanine green, anthraquinone green, titanium oxide, zinc flower,
and lithopone are included. These may be used alone or in combination of
[0037]The amount of the colorant in the colored particle (the toner base)
is not particularly limited, can be appropriately selected depending on
the purpose, and is preferably 1% by mass to 15% by mass and more
preferably 3% by mass to 10% by mass.
[0038]When the amount is less than 1% by mass, a coloring force of the
toner is reduced. When it exceeds 15% by mass, dispersion defect of
pigments in the toner occurs, sometimes resulting in reducing the
coloring force and reducing an electric property of the toner.
[Master Batch]
[0039]The colorant may be used as a master batch formulated with the
resin. The resin is not particularly limited, can be appropriately
selected from those known publicly depending on the purpose, and
includes, for example, polymers of styrene or substituents thereof,
styrene based copolymers, polymethyl methacrylate, polybutyl
methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene,
polypropylene, polyester, epoxy resins, epoxy polyol resins,
polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resins,
rosin, modified rosin, terpene resins, aliphatic hydrocarbon resins,
alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated
paraffin, and paraffin wax. These may be used alone or in combination of
[0040]The polymers of styrene or the substituents thereof include, for
example, polyester resins, polystyrene, poly-p-chlorostyrene, and
polyvinyl toluene. The styrene based copolymers include, for example,
styrene-p-chlorostyrene copolymers, styrene-propylene copolymers,
styrene-vinyl toluene copolymers, styrene-vinyl naphthalin 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
α-chloro-methacrylate 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-maleate ester copolymers.
[0041]The master batch can be produced by mixing or kneading the resin for
the master batch and the colorant with a high shearing force. At that
time, in order to enhance an interaction between the colorant ant the
resin, it is preferable to add an organic solvent. A wet cake of the
colorant can also be used directly in a so-called flushing method, and
this is suitable in terms of no need of drying. This flushing method is
the method in which an aqueous paste of the colorant containing the water
is mixed or kneaded together with the resin and the organic solvent, and
the colorant is allowed to migrate to a resin side followed by removing
water and the organic solvent component. A high shearing dispersing
apparatus such as three roll mill is suitably used for the above mixing
or kneading.
[0042]The releasing agent in the present invention is not particularly
limited, can be appropriately selected from those known publicly
depending on the purpose, and suitably includes, for example, waxes.
[0043]The waxes include, for example, carbonyl group-containing waxes,
polyolefin waxes, and long chain hydrocarbons. These may be used alone or
in combination of two or more. Among them, carbonyl group-containing
waxes are preferable.
[0044]The carbonyl group containing waxes include, for example, polyalkane
ester, polyalkanol ester, polyalkane amide, polyalkyl amide, and dialkyl
ketone. The polyalkane ester includes, for example, carnauba wax, montan
wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate,
pentaerythritol diacetate dibehenate, glycerine tribehenate, and
1,18-octadecanediol distearate. The polyalkanol ester includes, for
example, tristearyl trimellitate and distearyl maleate. The polyalkane
amide includes, for example, dibehenyl amide. The polyalkyl amide
includes, for example, tristearyl trimellitate amide. The dialkyl ketone
includes, for example, distearyl ketone. Among them carbonyl
group-containing waxes, polyalkane ester is preferable.
[0045]Polyolefin waxes include, for example, polyethylene wax and
polypropylene wax.
[0046]Long chain hydrocarbons include, for example, paraffin wax and Sasol
[0047]A melting point of the releasing agent is not particularly limited,
can be appropriately selected depending on the purpose, and is preferably
40° C. to 160° C., more preferably 50° C. to
120° C. and particularly preferably 60° C. to 90° C.
When the melting point is less than 40° C., the wax sometimes
harmfully affects the heat resistant storage stability. When it exceeds
160° C., cold offset sometimes occurs easily when fixed at low
[0048]The melt viscosity of the releasing agent is preferably 5 cps to
1,000 cps and more preferably 10 cps to 100 cps as a measured value at
temperature which is 20° C. higher than the melting point of the
wax. When the melt viscosity is less than 5 cps, the releasing property
is sometimes degraded. When it exceeds 1,000 cps, no enhancement effect
on hot offset resistance and fixing property at low temperature is not
sometimes obtained.
[0049]The amount of the releasing agent in the colored particle (the toner
base) is not particularly limited, can be appropriately selected
depending on the purpose, and is preferably 0% by mass to 40% by mass and
more preferably 3% by mass to 30% by mass. When the amount exceeds 40% by
mass, the fluidity of the toner is sometimes degraded.
[0050]In the present invention, other components may be contained in the
colored particle (the toner base particle). The other components are not
particularly limited, can be appropriately selected depending on the
purpose, and include, for example, charge controlling agents, fine
inorganic particles, fluidity enhancers, cleaning ability enhancers,
magnetic materials, metal soaps, and the organic silicone fine particle
[0051]The charge controlling agent is not particularly limited, can be
appropriately selected from those known publicly depending on the
purpose, and includes, for example, nigrosine based dyes,
triphenylmethane based dyes, chromium containing metal complex dyes,
molybdic acid chelate pigments, rhodamine based dyes, alkoxy based amine,
quaternary ammonium salts (including fluorine modified quaternary
ammonium salts), alkyl amide, a simple substance of phosphorus or
compounds thereof, a simple substance of tungsten or compounds thereof,
fluorine based active agents, metal salts of salicylic acid and metal
salts of salicylate derivatives. These may be used alone or in
[0052]As the charge controlling agent, commercially available products may
be used. The commercially available products include, for example,
BONTRON 03 of the nigrosine dye, BONTRON P-51 of the quaternary ammonium
salt, BONTRON S-34 of the metal-containing azo dye, E-82 of oxynaphthoic
acid-based metal complex, E-84 of salicylic acid-based metal complexes,
E-89 of phenol-based condensate (manufactured by Orient Chemical
Industries Ltd.); TP-302 and TP-415 of a quaternary ammonium salt
molybdenum complexes (manufactured by Hodogaya Chemical Co., Ltd.); Copy
Charge PSY VP2038 of the quaternary ammonium salts, Copy Blue PR of the
triphenylmethane derivative, Copy Charge NEG VP2036 and Copy Charge NX
VP434 of the quaternary ammonium salts (manufactured by Hoechst);
LRA-901, LR-147 which is a boron complex (manufactured by Japan Carlit
Co., Ltd.) copper phthalocyanine, perylene, quinacridone, azo-based
pigments, and polymer-based compounds having functional groups such as
sulfonic acid group, carboxyl group and quaternary ammonium salt are
[0053]The amount of the charge controlling agent in the colored particle
(the toner base particle) varies depending on the type of the resin, the
presence or absence of the additive, and the dispersion method, can not
be primarily defined, but is preferably 0.1 parts by mass to 10 parts by
mass and more preferably 0.2 parts by mass to 5 parts by mass relative to
100 parts by mass of the binder resin. When the amount is less than 0.1
parts by mass, the charge controlling property is not sometimes obtained.
When it exceeds 10 parts by mass, the charge property of the toner
becomes too large, the effect of the major charge controlling agent is
reduced, and an electrostatic sucking force with the developing roller is
increased, resulting in the reduction of fluidity of the developer and
the reduction of the image density.
[Colored Particle (Toner Base Particle)]
[0054]The toner of the present invention is composed of a colored particle
(a toner base particle) containing at least toner material including at
least a binder resin, a colorant and a releasing agent, and at least the
external additive of the present invention, and may contain preferably
other external additives, and further the other components if necessary.
[0055]The colored particle (the toner base particle) of the present
invention can be produced by pulverization method or polymerization
method such as suspension polymerization method, emulsification
polymerization method or melting suspension.
[0056]The pulverization method is such a method as obtaining base
particles of the toner by melting or kneading the toner materials, and
pulverizing and classifying them. In the case of the pulverization
method, for the purpose of enhancing an average circularity of the toner,
a mechanical impact force may be given to the obtained toner base
particles to control the shape. In this case, the mechanical impact force
can be imparted to the toner base particles using an apparatus such as
hybridizer and mechanofusion.
[0057]The above toner materials are mixed and the mixture is placed in a
melting/kneading machine to melt and knead it. As the melting/kneading
machine, uniaxial continuous kneaders, biaxial continuous kneaders, and
batch system kneaders by roll mill can be used. For example, KTK type
biaxial extruder manufactured by Kobe Steel, Ltd., TEM type extruder
manufactured by Toshiba Machine Co., Ltd., the biaxial extruder
manufactured by KCK, PCM type biaxial extruder manufactured by Ikegai
Tekkosho and the koneader manufactured by Bus are suitably used. It is
preferable to perform this melting/kneading under a proper condition not
to result in cleavage of a molecular chain of the binder resin.
Specifically, the melting/kneading temperature is determined with
reference to the softening point of the binder resin. When the
temperature is much higher than the softening point, the cleavage is
remarkable whereas when it is much lower than the softening point, the
dispersion does not proceed sometimes.
[0058]In the pulverization, the kneaded product obtained in the kneading
is pulverized. In this pulverization, it is preferable to first pulverize
roughly and subsequently pulverize finely the kneaded product. At that
time, the method of pulverizing by crushing to a crush plate in jet
stream, the method of pulverizing by crushing particles one another in
jet stream and the method of pulverizing in a narrow gap between a
mechanically rotating rotor and stator are preferably used.
[0059]In the classification, a pulverized product obtained in the above
pulverization is classified to adjust to particles having the given
particle diameter. For example, the classification can be performed by
removing a fine particle fraction by cyclone, decanter or centrifugation.
[0060]After completion of the pulverization and classification, the
pulverized product is classified in gas flow with a centrifugal force to
produce the toner base particle having the given particle diameters.
[Production of Colored Particle (Toner Base Particle) by Polymerization
[0061]In the polymerization method, the toner base particle can be
obtained by emulsifying or dispersing a solution or a dispersion of the
toner materials in a aqueous medium to prepare an emulsion or dispersion
and subsequently granulating.
[0062]A preferable aspect of the toner of the present invention includes
the toner base particle obtained by emulsifying or dispersing a solution
or a dispersion of the toner materials containing at least an active
hydrogen group-containing compound and a modified polyester resin
(hereinafter also referred to as the "prepolymer") capable of reacting
with the active hydrogen group-containing compound in the aqueous medium,
and reacting the active hydrogen group-containing compound with a
modified polyester resin (prepolymer) capable of reacting with the active
hydrogen group-containing compound to generate particles containing at
least an adhesive base.
[Solution or Dispersion of Toner Materials]
[0063]Hereinafter, the toner base particle in preferable aspects of the
[0064]The solution or the dispersion of the toner materials is obtained by
dissolving or dispersing the toner materials in a solvent. The toner
materials are not particularly limited as long as they can form the
toner, can be appropriately selected depending on the purpose, and for
example, include at least either the active hydrogen group-containing
compound and the modified polyester resin (prepolymer) capable of
reacting the active hydrogen group-containing compound, include the
fixing aid, the colorant, and the wax, and further if necessary include
the other components described above such as unmodified polyester resins,
and releasing agents and charge controlling agents.
[0065]It is preferable that the solution or the dispersion of the toner
materials is prepared by dissolving or dispersing the toner materials in
an organic solvent. It is preferable to remove the organic solvent upon
granulation or after the granulation of the toner.
[0066]The organic solvent is not particularly limited as long as it is the
solvent capable of dissolving or dispersing the toner materials, can be
appropriately selected depending on the purpose, and for example, one
which has a boiling point of lower than 150° C. and is volatile is
preferable in terms of easiness of its removal. For example, toluene,
xylene, benzene, carbon tetrachloride, methylene chloride,
1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform,
monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate,
methylethylketone and methyl isobutyl ketone are included. It is
preferable to be an ester based solvent, and ethyl acetate is
particularly preferable. These may be used alone or in combination of two
[0067]The amount of the organic solvent to be used is not particularly
limited, can be appropriately selected depending on the purpose, and is,
for example, preferably 40 parts by mass to 300 parts by mass, more
preferably 60 parts by mass to 140 parts by mass and still more
preferably 80 parts by mass to 120 parts by mass relative to 100 parts by
mass of the toner materials.
[0068]In the method of producing the toner base particle in the preferable
aspects of the present invention, the solution or the dispersion of the
toner materials can be prepared by dissolving or dispersing the toner
materials e.g., the active hydrogen group-containing compound, the
prepolymer capable of reacting with the active hydrogen group-containing
compound, the fixing aid, the unmodified polyester resin, the wax, the
colorant, the charge controlling agent, and the like in the organic
solvent. In the toner materials, the components other than the modified
polyester resin (prepolymer) capable of reacting with the active hydrogen
group-containing compound may be added and mixed in the aqueous medium in
the preparation of the aqueous medium described later, or may be added
together with the solution or the dispersion in the aqueous medium when
the solution or the dispersion of the toner materials is added to the
[Active Hydrogen Group-Containing Compound]
[0069]The active hydrogen group-containing compound acts as an extending
agent or a crosslinking agent when the prepolymer capable of reacting the
active hydrogen group-containing compound performs an extending reaction
or a crosslinking reaction in the aqueous medium.
[0070]The active hydrogen group-containing compound is not particularly
limited as long as it has the active hydrogen, and can be appropriately
selected depending on the purpose. For example, when the prepolymer
capable of reacting with the active hydrogen group-containing compound is
a polyester prepolymer (A) having the isocyanate group, amines (B) is
preferable because of being capable of making it have a high molecular
weight by the extending reaction or the crosslinking reaction with the
polyester prepolymer (A) containing the isocyanate group.
[0071]The active hydrogen group is not particularly limited, can be
appropriately selected depending on the purpose, and includes hydroxyl
groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino
groups, carboxyl groups and mercapto groups. These may be used alone or
in combination of two or more. Among them, the alcoholic hydroxyl groups
[0072]The amines (B) are not particularly limited, can be appropriately
selected depending on the purpose, and include diamine (B1), trivalent or
more polyamine (B2), amino alcohol (B3), aminomercaptan (B4) amino acids
(B5) and those (B6) obtained by blocking amino group in the B1 to B5.
[0073]These may be used alone or in combination of two or more.
[0074]Among them, diamine (B1) or a mixture of diamine (B1) and trivalent
or more polyamine (B2) in a small amount is particularly preferable.
[0075]Diamine (B1) includes aromatic diamine, alicyclic diamine, aliphatic
diamine. Aromatic diamine includes phenylenediamine,
diethyltoluenediamine and 4,4'-diaminodiphenylmethane. Alicyclic diamine
includes 4,4'-diamino-3,3'-dimethyldicyclohexylmethane,
diaminocyclohexane and isophoronediamine. Aliphatic diamine includes
ethylenediamine, tetramethylenediamine and hexamethylenediamine.
[0076]Trivalent or more polyamine (B2) includes diethylenetriamine and
triethylenetetraamine.
[0077]Amino alcohol (B3) includes ethanolamine and hydroxyethylaniline.
[0078]Aminomercaptan (B4) includes aminoethylmercaptan and
aminopropylmercaptan.
[0079]Amino acid (B5) includes aminopropionic acid and aminocaproic acid.
[0080]Those (B6) obtained by blocking the amino group in the (B1) to (B5)
include ketimine compounds and oxazoline compounds obtained from amines
in the (B1) to (B5) and ketones (acetone, methylethylketone, methyl
isobutyl ketone).
[0081]To terminate the extending reaction or the crosslinking reaction of
the active hydrogen group-containing compound with the polymer capable of
reacting with the active hydrogen group-containing compound, a reaction
terminator can be used. It is preferable to use the reaction terminator
because the molecular weight of the adhesive base can be controlled in a
desired range. The reaction terminator includes monoamine (diethylamine,
dibutylamine, butylamine, laurylamine), or those (ketimine compounds)
obtained by blocking them.
[0082]For the ratio of the polyester prepolymer (A) containing the
isocyanate group to amines (B), a mixed equivalent ratio [NCO]/[NHx] of
the isocyanate group [NCO] in the prepolymer (A) containing the
isocyanate group to the amino group [NHx] in amines (B) is preferably 1/3
to 3/1, more preferably 1/2 to 2/1 and particularly preferably 1/1.5 to
1.5/1.
[0083]When the mixed equivalent ratio [NCO]/[NHx] is less than 1/3, the
fixing property at low temperature is sometimes reduced. When it is
larger than 3/1, the molecular weight of the urea-modified polyester
resin becomes small, and the hot offset resistance is sometimes degraded.
[Modified Polyester Polymer (Prepolymer) Capable of Reacting With Active
Hydrogen Group-Containing Compound]
[0084]The prepolymer capable of reacting with the active hydrogen
group-containing compound is not particularly limited as long as it at
least has a site capable of reacting with the active hydrogen
group-containing compound. These may be used alone or in combination of
two or more. Among them, the modified polyester resin is particularly
preferable in terms of high fluidity upon melting and transparency.
[0085]The site capable of reacting with the active hydrogen
group-containing compound in the prepolymer is not particularly limited,
can be appropriately selected from publicly known substituent groups, and
includes, for example, an isocyanate group, an epoxy group, a carboxylic
group and an acid chloride group.
[0086]These may be included alone or in combination of two or more. Among
them, the isocyanate group is particularly preferable.
[0087]Among the prepolymers, urea bond generating group-containing
polyester resins (RMPE) are particularly preferable because the molecular
weight of a high molecular component is easily controlled, an oilless
fixing property at low temperature can be assured in a dry toner, and in
particular, in the case of having no releasing oil application mechanism
to a heating medium for fixing, the good releasing property and fixing
property can be assured.
[0088]The urea bond generating group includes, for example the isocyanate
group. When the urea bond generating group in the urea bond generating
group-containing polyester resin (RMPE) is the isocyanate group, the
polyester resin (RMPE) particularly suitably includes the isocyanate
group-containing polyester prepolymer (A).
[0089]The isocyanate group-containing polyester prepolymer (A) is not
purpose, and includes, for example, polycondensates of polyol (PO) and
polycarboxylic acid (PC), with the active hydrogen group-containing
polyester resin reacted with polyisocyanate (PIC).
[0090]The polyol (PO) is not particularly limited, can be appropriately
selected depending on the purpose, and includes, for example, diol (DIO),
trivalent or more polyol (TO) and mixtures of diol (DIO) and trivalent or
more polyol (TO). These may be used alone or in combination of two or
more. Among them, the diol (DIO) alone or the mixture of the diol (DIO)
and the trivalent or more polyol (TO) in a small amount is preferable.
[0091]The diol (DIO) includes, for example, alkylene glycol, alkylene
ether glycol, alicyclic diol, alkylene oxide adducts of alicyclic diol,
bisphenols and alkylene oxide adducts of bisphenols.
[0092]The alkylene glycol has preferably 2 to 12 carbon atoms, and
includes, for example, ethylene glycol, 1,2-propylene glycol,
1,3-propylene glycol, 1,4-butanediol and 1,6-hexanediol. The alkylene
ether glycol includes, for example, diethylene glycol, triethylene
glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol and
polytetramethylene ether glycol. The alicyclic diol includes, for
example, 1,4-cyclohexane dimethanol and hydrogenated bisphenol A. The
alkylene oxide adducts of the alicyclic diol include adducts to the
alicyclic diol of alkylene oxide such as ethylene oxide, propylene oxide
and butylene oxide. The bisphenols include, for example, bisphenol A,
bisphenol F and bisphenol S. The alkylene oxide adducts of the bisphenols
include, for example, those obtained by adding alkylene oxide such as
ethylene oxide, propylene oxide and butylene oxide to the bisphenols.
[0093]Among them, alkylene glycol having 2 to 12 carbon atoms and alkylene
oxide adducts of bisphenols are preferable. The alkylene oxide adducts of
bisphenols, or the mixture of the alkylene oxide adducts of bisphenols
and alkylene glycol having 2 to 12 carbon atoms is particularly
[0094]As the trivalent or more polyol (TO), trivalent to octavalent or
more ones are preferable, and for example, trivalent or more polyvalent
aliphatic alcohol, trivalent or more polyphenols, and alkylene oxide
adducts of trivalent or more polyphenols are included.
[0095]The trivalent or more polyvalent aliphatic alcohol includes, for
example, glycerine, trimethylolethane, trimethylolpropane,
pentaerythritol, and sorbitol. The trivalent or more polyphenols include,
for example, trisphenol PA, phenol novolak, and cresol novolak. The
alkylene oxide adducts of trivalent or more polyphenols include, for
example, those obtained by adding alkylene oxide such as ethylene oxide,
propylene oxide, and butylene oxide to the trivalent or more polyphenols.
[0096]In the mixture of the diol (DIO) and the trivalent or more polyol
(TO), a mixed mass ratio (DIO:TO) of the diol (DIO) to the trivalent or
more polyol (TO) is preferably 100:0.001 to 10 and more preferably
100:0.01 to 1.
[0097]The polycarboxylic acid (PC) is not particularly limited, can be
appropriately selected depending on the purpose, and includes, for
example, dicarboxylic acid (DIC), trivalent or more polycarboxylic acid
(TC), and mixtures of dicarboxylic acid (DIC) and trivalent or more
polycarboxylic acid (TC).
[0098]These may be used alone or in combination of two or more. Among
them, dicarboxylic acid (DIC) alone or the mixture of DIC and trivalent
or more polycarboxylic acid (TC) in a small amount is preferable.
[0099]The dicarboxylic acid includes, for example, alkylene dicarboxylic
acid, alkenylene dicarboxylic acid and aromatic dicarboxylic acid.
[0100]The alkylene dicarboxylic acid includes, for example, succinic acid,
adipic acid and sebacic acid. The alkenylene dicarboxylic acid preferably
has 4 to 20 carbon atoms and includes, for example, maleic acid and
fumaric acid. The aromatic dicarboxylic acid preferably has 8 to 20
carbon atoms and includes, for example, phthalic acid, isophthalic acid,
terephthalic acid and naphthalene dicarboxylic acid.
[0101]Among them, alkenylene dicarboxylic acid having 4 to 20 carbon atoms
and aromatic dicarboxylic acid having 8 to 20 carbon atoms are
[0102]The trivalent or more polycarboxylic acid (TO) is preferably
trivalent to octavalent or more ones, and includes, for example, aromatic
[0103]The aromatic polycarboxylic acids preferably have 9 to 20 carbon
atoms, and include, for example, trimellitic acid and pyromellitic acid.
[0104]As the polycarboxylic acid (PC), it is possible to also use acid
anhydrate or lower alkyl ester of any ones selected from the dicarboxylic
acid (DIC), the trivalent or more polycarboxylic acid (TC), and the
mixture of the dicarboxylic acid (DIC) and the trivalent or more
polycarboxylic acid (TC). The lower alkyl ester includes, for example,
methyl ester, ethyl ester, and isopropyl ester.
[0105]In the mixture of the dicarboxylic acid (DIC) and the trivalent or
more polycarboxylic acid (TC), the mixed mass ratio (DIC:TC) of the
dicarboxylic acid (DIC) to the trivalent or more polycarboxylic acid (TC)
the purpose, and for example, is preferably 100:0.01 to 10 and more
preferably 100:0.01 to 1.
[0106]A mixed ratio when the polyol (PO) and the polycarboxylic acid (PC)
are polycondensed is not particularly limited, can be appropriately
selected depending on the purpose, and for example, an equivalent ratio
([OH]/[COOH]) of hydroxyl group [OH] in the polyol (PO) to carboxyl group
[COOH] in the polycarboxylic acid (PC) is preferably 2/1 to 1/1
typically, more preferably 1.5/1 to 1/1 and particularly preferably 1.3/1
to 1.02/1.
[0107]The amount of the polyol (PO) in the isocyanate group-containing
polyester prepolymer (A) is not particularly limited, can be
appropriately selected depending on the purpose, and is preferably 0.5%
by mass to 40% by mass, more preferably 1% by mass to 30% by mass and
particularly preferably 2% by mass to 20% by mass.
[0108]When the amount is less than 0.5% by mass, the hot offset resistance
is degraded, and it sometimes becomes difficult to balance the heat
resistant storage stability and the fixing property at low temperature of
the toner. When it exceeds 40% by mass, the fixing property at low
temperature is sometimes degraded.
[0109]The polyisocyanate (PIC) is not particularly limited, can be
example, aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic
diisocyanate, aromatic aliphatic diisocyanate, isocyanurates, phenol
derivatives thereof and those obtained by blocking them with oxime or
[0110]The aliphatic polyisocyanate includes, for example, tetramethylene
diusocyanate, hexamethylene diusocyanate, 2,6-diisocyanatomethyl
caproate, octamethylene diisocyanate, decamethylene diisocyanate,
dodecamethylene diisocyanate, tetradecamethylene diisocyanate,
trimethylhexane diisocyanate and tetramethylhexane diisocyanate. The
alicyclic polyisocyanate includes, for example, isophorone diisocyanate
and cyclohexylmethane diisocyanate. The aromatic diisocyanate includes,
for example, trilene diisocyanate, diphenylmethane diisocyanate,
1,5-naphthylene dilsocyanate, diphenyl-4,4'-diisocyanate,
4,4'-disocyanato-3,3'-dimethyldiphenyl,
3-methyldiphenylmethane-4,4'-diisocyanate, and diphenyl
ether-4,4'-diisocyanate. The aromatic aliphatic diisocyanate includes,
for example, α,α,α',α'-tetramethylxylylene
diisocyanate. The isocyanurates includes, for example,
tris-isocyanatoalkyl-isocyanurate and
triisocyanatocycloalkyl-isocyanurate. These may be used alone or in
[0111]For the mixed ratio when the polyisocyanate (PIC) is reacted with
the active hydrogen group-containing polyester resin (e.g., hydroxyl
group-containing polyester resin), the mixed equivalent ratio
([NCO]/[OH]) of the isocyanate group [NCO] in the polyisocyanate (PIC) to
the hydroxyl group [OH] in the hydroxyl group-containing polyester resin
is preferably 5/1 to 1/1 typically, more preferably 4/1 to 1.2/1 and
particularly preferably 3/1 to 1.5/1.
[0112]When this ratio exceeds 5/1, the fixing property at low temperature
is sometimes degraded. When it is less than 1, the offset resistance is
sometimes degraded.
[0113]The amount of the polyisocyanate (PIC) in the isocyanate
group-containing polyester prepolymer (A) is not particularly limited,
can be selected depending on the purpose, and is, for example, preferably
0.5% by mass to 40% by mass, more preferably 1% by mass to 30% by mass
and still more preferably 2% by mass to 20% by mass.
[0114]When the amount is less than 0.5% by mass, the hot offset resistance
resistant storage stability and the fixing property at low temperature.
When it exceeds 40% by mass, the fixing property at low temperature is
[0115]An average number of the isocyanate group contained per molecule of
the isocyanate group-containing polyester prepolymers (A) is preferably
one or more, more preferably 1.2 to 5 and still more preferably 1.5 to 4.
[0116]When the average number of the isocyanate groups is less than 1, the
molecular weight of the polyester resin (RMPE) modified with the urea
bond-generating group becomes low, and the hot offset resistance is
[0117]A mass average molecular weight (Mw) of the modified polyester
resins capable of reacting with the active hydrogen group-containing
compound is preferably 3,000 to 40,000 and more preferably 4,000 to
30,000 by a molecular weight distribution by GPC (gel permeation
chromatography) of a fraction soluble in tetrahydrofuran (THF). When the
mass average molecular weight (Mw) is less than 3,000, the heat resistant
storage stability is sometimes degraded. When it exceeds 40,000, the
fixing property at low temperature is sometimes degraded.
[0118]The molecular weight distribution can be measured, for example, as
follows by gel permeation chromatography (GPC).
[0119]First, a column is stabilized in a heat chamber at 40° C. At
this temperature, tetrahydrofuran (THF) is run at a flow rate of 1
ml/minute as a column solvent, and 50 μL to 200 μL of a resin
sample solution in tetrahydrofuran adjusted at a sample concentration in
the range of 0.05% by mass to 0.6% by mass is injected for measurement.
[0120]Upon measurement of the molecular weight in the sample, the
molecular weight distribution of the sample is calculated from the
relation of logarithmic values of a standard curve made from several
monodispersion polystyrene standard samples with counted numbers. As the
standard polystyrene samples for making the standard curve, those having
molecular weights of 6×102, 2.1×102,
4×102, 1.75×104, 1.1×105,
3.9×105, 8.6×105, 2×106, and
4.48×106 (manufactured by Pressure Chemical Co. or Toyo Soda
Kogyo Co., Ltd.) are used, and it is preferable to use at least about 10
standard polystyrene samples. As a detector, an RI (refractive index)
detector can be used.
[0121]The aqueous medium is not particularly limited, can be appropriately
selected from those known publicly and includes, for example, water,
solvents miscible with the water, and mixtures thereof. Among them, the
water is particularly preferable.
[0122]The solvent miscible with the water is not particularly limited as
long as it is miscible with the water, and includes, for example,
alcohol, dimethylformamide, tetrahydrofuran, cellsolves, and lower
[0123]The alcohol includes, for example, methanol, isopropanol, and
ethylene glycol. The lower ketones include, for example, acetone and
methylethylketone. These may be used alone or in combination of two or
[0124]The aqueous medium can be prepared, for example, by dispersing the
resin fine particles in the aqueous medium. The resin fine particles may
be the organic silicone resin fine particle of the present invention or
other resin fine particles. The amount of the resin fine particles to be
added into the aqueous medium is not particularly limited, can be
appropriately selected depending on the purpose, and is preferably, for
example, 0.5% by mass to 10% by mass.
[0125]The resin fine particle, even when it is those other than the
organic silicone resin fine particle of the present invention, is not
particularly limited as long as it can form an aqueous dispersion in the
aqueous medium, can be appropriately selected from publicly known resins
depending on the purpose, may be a thermoplastic resin or a thermosetting
resin, and includes, for example, vinyl resins, polyurethane resins,
epoxy resins, polyester resins, polyamide resins, polyimide resins,
silicon resins, phenol resins, melamine resins, urea resins, aniline
resins, ionomer resins, and polycarbonate resins.
[0126]These may be used alone or in combination of two or more. Among
them, it is preferable to be formed of at least one selected from vinyl
resins, polyurethane resins, epoxy resins, and polyester resins because
the aqueous dispersion of fine spherical resin particles is easily
[0127]The vinyl resin is the polymer obtained by homopolymerizing or
copolymerizing a vinyl monomer(s), and includes styrene-(meth)acrylate
ester resins, styrene-butadiene copolymers, (meth)acrylic acid-acrylate
ester polymers, styrene-acrylonitrile copolymers, styrene-maleic acid
anhydrate, and styrene-(meth)acrylic acid copolymers.
[0128]As the resin fine particle, the copolymer including a monomer having
at least two unsaturated groups and the organic silicone fine particle of
the present invention can also be used. The monomer having at least two
unsaturated groups is not particularly limited, can be appropriately
selected depending on the purpose, and includes, for example, sodium salt
of methacrylic acid ethylene oxide adduct sulfate ester ("ELEMINOL RS-30"
manufactured by Sanyo Chemical Industries, Ltd.), divinyl benzene and
1,6-hexanediol acrylate.
[0129]The resin fine particle can be obtained by polymerizing according to
the publicly known method appropriately selected depending on the
purpose, and it is preferable to obtain as the aqueous dispersion of the
resin fine particles. The method of preparing the aqueous dispersion of
the resin fine particles suitably includes, for example, (1) the method
of directly producing the aqueous dispersion of the resin fine particles
using the vinyl monomer as a starting material using any polymerization
method selected from a suspension polymerization method, an
emulsification polymerization method, a seed polymerization method and a
dispersion polymerization method in the case of the vinyl resin; (2) the
method of producing the aqueous dispersion of the resin fine particles by
dispersing a precursor (monomer, or oligomer) or a solvent solution
thereof in the aqueous medium in the presence of an appropriate
dispersant, and subsequently heating or adding a curing agent to cure, in
the case of polyaddition resins or condensation resins such as the
polyester resin, polyurethane resin, or epoxy resin; (3) the method of
dissolving an appropriate emulsifier in the precursor (monomer, or
oligomer) or the solvent solution thereof (preferably being a liquid or
may be liquefied by heating) and subsequently adding water to emulsify
with phase inversion, in the case of polyaddition resins or condensation
resins such as the polyester resin, polyurethane resin, or epoxy resin;
(4) the method of pulverizing the resin previously prepared by a
polymerization reaction (may be any polymerization reaction type of
addition polymerization, ring opening polymerization, polyaddition,
addition condensation, and polycondensation) using a mechanically rotary
or jet pulverizer, then classifying to yield the resin fine particles,
and subsequently dispersing them in water in the presence of the
appropriate dispersant; (5) the method of yielding the resin fine
particles by atomizing/spraying a resin solution in which the resin
previously prepared by a polymerization reaction (may be any
polymerization reaction type of addition polymerization, ring opening
polymerization, polyaddition, addition condensation and polycondensation)
has been dissolved in a solvent and then dispersing them in water in the
presence of the appropriate dispersant; (6) the method of precipitating
the resin fine particles by adding a poor solvent to the resin solution
in which the resin previously prepared by a polymerization reaction (may
be any polymerization reaction type of addition polymerization, ring
opening polymerization, polyaddition, addition condensation and
polycondensation) has been dissolved in a solvent or cooling the resin
solution in which the resin has been previously dissolved with heating in
a solvent, subsequently removing the solvent to yield the resin fine
particles, and then dispersing them in water in the presence of the
appropriate dispersant; (7) the method of dispersing the resin solution
polycondensation) has been dissolved in a solvent in the aqueous medium
in the presence of the appropriate dispersant, and subsequently removing
the solvent by heating or reducing pressure; and (8) the method of
dissolving the appropriate emulsifier in the resin solution in which the
resin previously prepared by a polymerization reaction (may be any
has been dissolved in a solvent, and subsequently adding the water to
emulsify with phase inversion.
[Emulsification or Dispersion]
[0130]For emulsifying or dispersing the solution or the dispersion of the
toner materials in the aqueous medium, it is preferable to disperse the
solution or the dispersion of the toner materials with stirring in the
aqueous medium. The dispersion method is not particularly limited, can be
appropriately selected depending on the purpose, and can be performed,
for example, using a known dispersing machine. The dispersing machine
includes the low speed shearing dispersing machine and the high speed
shearing dispersing machine.
[0131]The method of stably forming the dispersion body containig the
polymer (e.g., the isocyanate group-containing polyester prepolymer (A))
capable of reacting with the active hydrogen group-containing compound in
the aqueous medium includes, for example, the method of adding the
solution or the dispersion of the toner materials prepared by dissolving
or dispersing the toner materials, e.g., the prepolymer (e.g., the
isocyanate group-containing polyester prepolymer (A)) capable of reacting
with the active hydrogen group-containing compound, the colorant, the
releasing agent, the charge controlling agent, and the unmodified
polyester resin in the organic solvent in the aqueous medium, and
dispersing them with a shearing force.
[0132]In the emulsification or dispersion, the amount of the aqueous
medium to be used is preferably 50 parts by mass to 2,000 parts by mass
and more preferably 100 parts by mass to 1,000 parts by mass relative to
100 parts by mass of the toner materials. When the amount to be used is
less than 50 parts by mass, the dispersion of the toner materials is poor
and the toner particle having the given particle diameter is not
sometimes obtained. When it exceeds 2,000 parts by mass, production cost
sometimes becomes high.
[0133]In the emulsification or dispersion, it is preferable to use a
dispersant for stabilizing the oil drops and making the particle size
distribution sharp with keeping the desired shape.
[0134]The dispersant is not particularly limited, can be appropriately
selected depending on the purpose, and includes, for example,
surfactants, water hardly soluble inorganic compound dispersants, and
polymer based protection colloid. These may be used alone or in
combination of two or more. Among them the surfactant is preferable.
[0135]The surfactant includes, for example, anion surfactants, cation
surfactants, nonionic surfactants and ampholytic surfactants.
[0136]The anion surfactants include, for example, alkylbenzene sulfonate
salts, α-olefin sulfonate salts and phosphate esters. Among them,
those having fluoroalkyl group are suitably included. The anion
surfactants having the fluoroalkyl group include, for example,
fluoroalkyl carboxylic acids having 2 to 10 carbon atoms or metal salts
thereof, disodium perfluorooctanesulfonyl glutamate, sodium
3-[omega-fluoroalkyl (C6 to 11) oxy]-1-alkyl (C3 to 4) sulfonate, sodium
3-[omega-fluoroalkanoyl (C6 to 8)-N-ethylamino]-1-propane sulfonate,
fluoroalkyl (C11 to 20) carboxylic acids or metal salts thereof,
perfluoroalkyl carboxylic acids (C7 to 13) or metal salts thereof,
perfluoroalkyl sulfonic acids (C4 to 12) or metal salts thereof,
perfluorooctane sulfonic acid diethanolamide, N-propyl-N-(2-hydroxyethyl)
perfluorooctane sulfonamide, perfluoroalkyl (C6 to 10) sulfonamide
propyltrimethyl ammonium salts, perfluoroalkyl (C6 to 10)-N-ethylsulfonyl
glycine salts, and monoperfluoroalkyl (C6 to 16) ethyl phosphate ester.
Commercially available surfactants having the fluoroalkyl group include,
for example, Surflon S-111, S-112, and S-113 (manufactured by Asahi Glass
Co., Ltd.), Fullard FC-93, FC-95, FC-98, and FC-129 (manufactured by
Sumitomo 3M Ltd.), Unidain DS-101 and DS-102 (manufactured by Daikin
Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, and F-833
(manufactured by Dainippon Ink And Chemicals, Incorporated), F-Top
EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, and 204
(manufactured by Tohchem Products Co., Ltd.), and Ftergent F-100 and
F-150 (manufactured by Neos Corporation).
[0137]The cation surfactants include, for example, amine salt type
surfactants and quaternary ammonium salt type cation surfactants. The
amine salt type surfactants include, for example, alkylamine salts, amino
alcohol fatty acid derivatives, polyamine fatty acid derivatives, and
imidazoline. The quaternary ammonium salt type cation surfactants
include, for example, alkyltrimethyl ammonium salts, dialkyldimethyl
ammonium salts, alkyldimethylbenzyl ammonium salts, pyridinium salts,
alkylisoquinolinium salts, and benzethonium chloride. Among the cation
surfactants, aliphatic primary, secondary and tertiary amine acids having
the fluoroalkyl group, aliphatic quaternary ammonium salts such as
perfluoroalkyl (C6 to 10) sulfonamide propyltrimethyl ammonium salts,
benzalkonium salts, benzethonium chloride, pyridinium salts, and
imidazolium salts are included. Commercially available products of the
cation surfactants include, for example, Surflon S-121 (manufactured by
Asahi Glass Co., Ltd.), Fullard FC-135 (manufactured by Sumitomo 3M
Ltd.), Unidain DS-202 (manufactured by Daikin Industries, Ltd.), Megafac
F-150 and F-824 (manufactured by Dainippon Ink And Chemicals,
Incorporated), F-Top EF-132 (manufactured by Tohchem Products Co., Ltd.)
and Ftergent F-300(manufactured by Neos Corporation).
[0138]The nonionic surfactants include, for example, fatty acid amide
derivatives and polyvalent alcohol derivatives.
[0139]The ampholytic surfactants include, for example, alanine,
dodecyldi(aminoethyl)glycine, di(octylaminoethyl)glycine, and
N-alkyl-N,N-dimethyl ammonium betaine.
[0140]In the preparation of the dispersion, a dispersion stabilizer can be
[0141]The dispersion stabilizer includes, for example, those such as
calcium phosphate salt which are soluble in acid or alkali. When the
dispersion stabilizer is used, the calcium phosphate salt can be removed
by dissolving the calcium phosphate salt with the acid such as
hydrochloric acid and washing with water or decomposing with an enzyme.
[0142]In the preparation of the dispersion, a catalyst for the extending
reaction or the crosslinking reaction can be used. The catalyst includes,
for example, dibutyl tin laurate and dioctyl tin laurate.
[Adhesive Base]
[0143]In the method of producing the toner base particle of the preferable
aspect of the present invention, the adhesive base (the above resin) is
generated by performing the extending reaction or the crosslinking
reaction between the active hydrogen group-containing compound and the
polymer capable of reacting with the active hydrogen group-containing
compound upon the emulsification or dispersion
[0144]The adhesive base exhibits an adhesiveness to the recording medium
such as papers, contains at least an adhesive polymer obtained by
reacting the active hydrogen group-containing compound with the polymer
the aqueous medium, and may further contain a binder resin appropriately
selected from publicly known binder resins.
[0145]The mass average molecular weight of the adhesive bases is not
purpose, and for example, is preferably 3,000 or more, more preferably
5,000 to 1,000,000, and particularly preferably 7,000 to 500,000.
[0146]When the mass average molecular weight is less than 3,000, the hot
offset resistance is sometimes degraded.
[0147]The glass transition temperature (Tg) of the adhesive base is not
purpose, and for example, is preferably 30° C. to 70° C.
and more preferably 40° C. to 65° C. In the toner, since
the polyester resin obtained by the crosslinking reaction or the
extending reaction coexists, the toner exhibits the good storage
stability even when the glass transition temperature is low compared with
conventional polyester based toners.
[0148]When the glass transition temperature (Tg) is lower than 30°
C., the heat resistant storage stability is sometimes degraded. When it
is higher than 70° C., the fixing property at low temperature is
[0149]The glass transition temperature can be measured, for example, using
TG-DSC system TAS-100 (manufactured by Rigaku Denki Co., Ltd.) by the
following method. First, about 10 mg of a sample is placed in a sample
vessel made from aluminium, which is then placed on a holder unit and set
in an electric furnace. The temperature is raised from the room
temperature up to 150° C. at a temperature rising speed of
10°C./min, left stand at 150° C. for 10 minutes, then
lowered to the room temperature and left stand for 10 minutes. DSC curve
measurement was performed using a differential scanning calorimeter (DSC)
by subsequently heating again up to 150° C. at a temperature
rising speed of 10°C./minute under nitrogen atmosphere. The glass
transition temperature (Tg) can be calculated from a tangent of an
endothermic curve in the vicinity of the glass transition temperature
(Tg) and a contact point with a base line using the analysis system in
TG-DSC system TAS-100 system.
[0150]Specific examples of the adhesive base are not particularly limited,
can be appropriately selected depending on the purpose, and particularly
suitably include polyester based resins.
[0151]The polyester based resins are not particularly limited, can be
appropriately selected depending on the purpose, and particularly
suitably include, for example urea modified polyester based resins.
[0152]The urea modified polyester based resin is obtained by reacting
amines (B) as the active hydrogen group-containing compound with the
isocyanate group-containing polyester prepolymer (A) as the polymer
[0153]The urea modified polyester based resin may contain an urethane bond
in addition to the urea bond. In this case, a molar content ratio of the
urea bond to the urethane bond (urea bond/urethane bond) is not
purpose, and is preferably 100/0 to 10/90, more preferably 80/20 to 20/80
and particularly preferably 60/40 to 30/70. When the urea bond is less
than 10, the hot offset resistance is sometimes degraded.
[0154]Specific examples of the urea modified polyester resin suitably
include the following (1) to (10), i.e., (1) a mixture of one obtained by
ureating with isophoronediamine a polyester prepolymer obtained by
reacting a polycondensate of a bisphenol A ethylene oxide 2 mol adduct
and isophthalic acid to isophorone diisocyanate, with the polycondensate
of the bisphenol A ethylene oxide 2 mol adduct and isophthalic acid; (2)
a mixture of one obtained by ureating with isophoronediamine a polyester
prepolymer obtained by reacting a polycondensate of a bisphenol A
ethylene oxide 2 mol adduct and isophthalic acid to isophorone
diisocyanate, with a polycondensate of the bisphenol A ethylene oxide 2
mol adduct and terephthalic acid; (3) a mixture of one obtained by
reacting a polycondensate of a bisphenol A ethylene oxide 2 mol
adductfbisphenol A propylene oxide 2 mol adduct and terephthalic acid to
isophorone diisocyanate, with the polycondensate of the bisphenol A
ethylene oxide 2 mol adduct/bisphenol A propylene oxide 2 mol adduct and
terephthalic acid; (4) a mixture of one obtained by ureating with
isophoronediamine a polyester prepolymer obtained by reacting a
polycondensate of a bisphenol A ethylene oxide 2 mol adduct/bisphenol A
propylene oxide 2 mol adduct and terephthalic acid to isophorone
diisocyanate, with a polycondensate of the bisphenol A propylene oxide 2
mol adduct and terephthalic acid; (5) a mixture of one obtained by
ureating with hexamethylenediamine a polyester prepolymer obtained by
and terephthalic acid to isophorone diisocyanate, with the polycondensate
of the bisphenol A ethylene oxide 2 mol adduct and terephthalic acid; (6)
a mixture of one obtained by ureating with hexamethylenediamine a
polyester prepolymer obtained by reacting a polycondensate of a bisphenol
A ethylene oxide 2 mol adduct and terephthalic acid to isophorone
diisocyanate, with the polycondensate of the bisphenol A ethylene oxide 2
mol adduct/bisphenol A propylene oxide 2 mol adduct and terephthalic
acid; (7) a mixture of one obtained by ureating with ethylenediamine a
mol adduct and terephthalic acid; (8) a mixture of one obtained by
and isophthalic acid to diphenylmethane diisocyanate, with the
polycondensate of the bisphenol A ethylene oxide 2 mol adduct and
isophthalic acid; (9) a mixture of one obtained by ureating with
hexamethylenediamine a polyester prepolymer obtained by reacting a
propylene oxide 2 mol adduct and terephthalic acid/docenyl succinic acid
anhydrate to diphenylmethane diisocyanate, with the polycondensate of the
bisphenol A ethylene oxide 2 mol adductfbisphenol A propylene oxide 2 mol
adduct and terephthalic acid; and (10) a mixture of one obtained by
and isophthalic acid to toluene diisocyanate, with the polycondensate of
the bisphenol A ethylene oxide 2 mol adduct and isophthalic acid.
[0155]The adhesive base (e.g., the urea modified polyester resin), for
example, (1) may be generated by emulsifying or dispersing the solution
or the dispersion of the toner materials including the polymer (e.g., the
with the active hydrogen group-containing compound together with the
active hydrogen group-containing compound (e.g., the amines (B)) in the
aqueous medium to form the oil drops, and subjecting both to the
extending reaction or the crosslinking reaction in the aqueous medium;
(2) may be generated by emulsifying or dispersing the solution or the
dispersion of the toner materials in the aqueous medium in which the
active hydrogen group-containing compound has been previously added to
form the oil drops, and subjecting both to the extending reaction or the
crosslinking reaction in the aqueous medium; and (3) may be generated by
adding and mixing the solution or the dispersion of the toner materials
in the aqueous medium, subsequently adding the active hydrogen
group-containing compound to form the oil drops and subjecting both to
the extending reaction or the crosslinking reaction from a particle
interface in the aqueous medium. In the above (3), the modified polyester
resin is preferentially generated on the surface of the toner generated,
and thus a density gradient can also be provided in the toner particles.
[0156]A reaction condition for generating the adhesive base by the
emulsification or dispersion is not particularly limited, and can be
appropriately selected depending on the combination of the polymer
capable of reacting with the active hydrogen group-containing compound
and the active hydrogen group-containing compound. A reaction time period
is preferably 10 minutes to 40 hours and more preferably 2 hours to 24
[Other Binder Resins]
[0157]In the present invention, other binder resin may be preferably used
at the same time. Other binder resin is not particularly limited, can be
example, polyester resins. In particular, the unmodified polyester resin
(polyester resin which is not modified) is preferable.
[0158]When the unmodified polyester resin is contained in the toner base
particle, the fixing property at low temperature and the glossiness can
[0159]The unmodified polyester resin includes the same ones as in the urea
bond generating group-containing polyester resin, i.e., the
polycondensates of polyol (PO) and polycarboxylic acid (PC). The
unmodified polyester resin is preferable in terms of fixing property at
low temperature and hot offset resistance because the unmodified
polyester resin is partially compatible with the urea bond generating
group-containing polyester based resin (RMPE), i.e., they have a similar
structure which enables them to be compatible partially with each other.
[0160]The mass average molecular weight (Mw) of the unmodified polyester
resins is preferably 1,000 to 30,000 and more preferably 1,500 to 15,000
by the molecular weight distribution by GPC (gel permeation
chromatography) of the fraction soluble in tetrahydrofuran (THF). When
the mass average molecular weight (Mw) is less than 1,000, the heat
resistant storage stability is sometimes degraded. Thus, it is preferable
that the amount of the components having the mass average molecular
weight (Mw) of less than 1,000 is 8% by mass to 28% by mass. Meanwhile,
when the mass average molecular weight exceeds 30,000, the fixing
property at low temperature is sometimes degraded.
[0161]The glass transition temperature of the unmodified polyester resin
is preferably 35° C. to 70° C. When the glass transition
temperature is lower than 35° C., the heat resistant storage
stability of the toner is sometimes degraded. When it is higher than
70° C., the fixing property at low temperature is sometimes
[0162]A hydroxyl group value of the unmodified polyester resin is
preferably 5 mg KOH/g or more, more preferably 10 mg KOH/g to 120 mg
KOH/g, and still more preferably 20 mg KOH/g to 80 mg KOH/g. When the
hydroxyl group value is less than 5 mg KOH/g, it sometimes becomes
difficult to balance the heat resistant storage stability and the fixing
property at low temperature.
[0163]An acid value of the unmodified polyester resin is preferably 1.0 mg
KOH/g to 30.0 mg KOH/g and more preferably 5.0 mg KOH/g to 20.0 mg KOH/g.
Generally by making the toner have the more acid value, the toner is the
more easily charged negatively.
[0164]When the unmodified polyester resin is contained in the toner, the
mixed mass ratio (RMPE/PE) of the urea bond generating group-containing
polyester resin (RMPE) to the unmodified polyester resin (PE) is
preferably 5/95 to 25/75 and more preferably 10/90 to 25/75.
[0165]When the mixed mass ratio of the unmodified polyester resin exceeds
95, the hot offset resistance is sometime degraded. When it is less than
75, the fixing property at low temperature and glossiness of the image
are sometimes degraded.
[Separation and Yield of Toner Base Particle]
[0166]The organic solvent is removed from the emulsified slurry obtained
in the emulsification or the dispersion.
[0167]The method of removing the organic solvent includes, for example,
(1) the method of removing by raising gradually the temperature in the
entire reaction system to completely evaporate the organic solvent in the
oil drops and (2) the method of completely removing the water insoluble
organic solvent in the oil drops to form the toner base particles by
spraying the emulsified dispersion body in a dried atmosphere and
simultaneously evaporating/removing the aqueous dispersant.
[0168]When the organic solvent is removed, the toner base particle is
formed. The toner base particle can be washed and dried. Subsequently,
the classification can be performed as desired. The classification can be
performed by removing the fine particle portion in liquid by cyclone,
decanter or centrifugation. The classification may be performed after
acquiring the powder after the drying.
[0169]By mixing the resulting toner base particle together with the
particles of the colorant, the releasing agent and the charge controlling
agent or by further applying a mechanical impact force, it is possible to
prevent the particles such as the releasing agent from dissociating from
the surface of the toner particles.
[0170]The method of applying the mechanical impact force includes the
method of applying the impact force to the mixture using blades which
rotate at high speed, and the method of placing the mixture in high speed
gas flow and crashing the particles one another or the complexed
particles to an appropriate crash plate by accelerating. An apparatus
used for this method includes Ang Mill (manufactured by Hosokawa Micron
Ltd.), an apparatus in which a pulverization air pressure has been
reduced by remodeling I type mill (manufactured by Nippon Pneumatic MFG.
Co., Ltd.), a hybridization system (Nara Machinery Co., Ltd.), a cryptron
system (manufactured by Kawasaki Heavy Industries, Ltd.), and an
automatic mortar.
[Production of Toner Base Particle in Case of Using Suspension
Polymerization Method]
[0171]The toner base particle produced by the suspension polymerization
[0172]The toner base particle produced by the suspension polymerization
method can be obtained by emulsifying or dispersing (suspending) the
solution or the dispersion of the toner materials in the aqueous medium
to prepare the emulsion or the dispersion (suspension), and then by
granulating the toner as described above.
[0173]In the suspension polymerization method, the solution or the
dispersion of the toner materials is obtained by dissolving or dispersing
the fixing aid, the colorant, further if necessary, components, e.g., the
wax, the charge controlling agent, and the crosslinking agent in a
polymerizable monomer and an oil soluble polymerization initiator. In
addition, for example, in order to reduce the viscosity in the polymer
produced in the polymerization reaction described later, the organic
solvent, a macromolecular polymer and the dispersant may be appropriately
[0174]A functional group can be introduced to the toner particle surface
by partially using as a polymerizable monomer acids such as acrylic acid,
methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic
acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, and maleic
acid anhydrate; acrylamide, methacrylamide, diacetone acrylamide or the
methylol compounds thereof; vinyl pyridine, vinyl pyrrolidone, vinyl
imidazole, ethylene imine, acrylate or methacrylate having an amino group
such as diethylaminoethyl methacrylate. The dispersant can be adsorbed
and left onto the toner particle surface to introduce the functional
group by appropriately selecting one having an acid group or a basic
group as the dispersant to be used.
[0175]The polymerizable monomer includes, for example, styrene based
monomers such as styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, and p-ethylstyrene; acrylate esters
such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl
acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate,
2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate and
phenyl acrylate; methacrylate esters such as methyl methacrylate, ethyl
methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl
methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl
methacrylate, stearyl methacrylate, phenyl methacrylate,
dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate;
other acrylonitrile, methacrylonitrile, and acrylamide.
[0176]The resin can also be used in addition to the polymerizable monomer.
For example, the polymerizable monomer is water soluble, is dissolved in
the aqueous suspension and the emulsification polymerization can not be
performed. Thus, when the polymerizable monomer which contains the
hydrophilic functional group such as an amino group, a carboxylate group,
a hydroxyl group, a sulfone group, a glycidyl group, or a nitrile group
is introduced in the toner, the resin which is the copolymer such as a
random copolymer, a block copolymer, or a graft copolymer of a vinyl
compound (such as styrene or ethylene) therewith, or the polycondensate
of polyester or polyamide therewith, or the polyaddition polymer of
polyether or polyimine therewith can be used.
[0177]The alcohol component and the acid component which form the
polyester resin include the followings.
[0178]The alcohol component includes, for example, ethylene glycol,
propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol,
diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol,
neopentyl glycol, 2-ethyl-1,3-hexanediol, cyclohexane dimethanol,
butenediol, octenediol, cyclohexene dimethanol and hydrogenated bisphenol
A. Polyvalent alcohol such as glycerine, pentaerythritol, sorbit,
sorbitan and oxyalkylene ether of novolak type phenol resins may also be
[0179]The acid component includes, for example, benzene dicarboxylic acids
such as phthalic acid, terephthalic acid, and isophthalic acid or
anhydrates thereof; alkyl dicarboxylic acids such as succinic acid,
adipic acid, sebacic acid, and azelaic acid or anhydrates thereof;
succinic acid substituted with an alkyl group or an alkenyl group having
6 to 18 carbon atoms or anhydrates thereof; and unsaturated dicarboxylic
acids such as fumaric acid, maleic acid, citraconic acid, and itaconic
acid or anhydrates thereof as bivalent carboxylic acids. Polyvalent
carboxylic acids such as trimellitic acid, pyromellitic acid,
1,2,3,4-butane tetracarboxylic acid, and benzophenone tetracarboxylic
acid and anhydrates thereof may also be used.
[0180]The amounts of the alcohol component and the acid component in the
polyester resin are preferably 45 mol % to 55 mol % and 55 mol % to 45
[0181]Two or more of the polyester resins may be used in combination as
long as no harmful effect is given to physical properties of the toner
base particle obtained. Further, the physical properties can be adjusted
by modifying with silicone or a fluoroalkyl group-containing compound.
[0182]When a macromolecular polymer containing such a polar functional
group is used here, the average molecular weight of the macromolecular
polymers is preferably 5,000 or more.
[0183]Furthermore, in addition to the polymerizable monomer, the resins
shown below may be used. The resins include, for example, homopolymers of
styrene and substituents thereof, e.g., polystyrene and polyvinyl
toluene; styrene based copolymers such as styrene-propylene copolymers,
styrene-vinyl toluene copolymers, styrene-vinyl naphthaline copolymers,
styrene-dimethylaminoethyl acrylate copolymers, styrene-methyl
methacrylate copolymers, styrene-ethyl methacrylate copolymers,
styrene-butyl methacrylate copolymers, styrene-dimethylaminoethyl
methacrylate copolymers, styrene-vinyl methyl ether copolymers,
styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone
copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers,
styrene-maleic acid copolymers and styrene maleate ester copolymers;
polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate,
polyethylene, polypropylene, polyvinyl butyral, silicone resins,
polyester resins, polyamide resins, epoxy resins, polyacrylic acid
resins, rosin, modified rosin, terpene resins, phenol resins, aliphatic
or alicyclic hydrocarbon resins, and aromatic petroleum resins. These may
[0184]The amount of the resin to be added is preferably 1 part by mass to
20 parts by mass relative to 100 parts by mass of the polymerizable
monomer. When the amount to be added is less than 1 part by mass, no
effect by its addition sometimes occurs on the adjustment of the physical
properties of the toner particles. When it exceeds 20 parts by mass, it
sometimes becomes difficult to design the physical properties of the
toner particles. The polymer having the different molecular weight from
the molecular weight range of the toner obtained by polymerizing the
polymerizable monomer can also be dissolved in and polymerized with the
[0185]When the polymerization reaction is performed using 0.5 parts by
mass to 20 parts by mass of the oil soluble polymerization initiator
having a half life of 0.5 hours to 30 hours upon polymerization reaction
relative to 100 parts by mass of the polymerizable monomer, it is
possible to yield the polymer having the maximum molecular weight between
10,000 to 100,000, and impart the desirable strength and the appropriate
solubility to the toner.
[0186]The oil soluble polymerization initiator is not particularly limited
as long as it is oil soluble, can be appropriately selected depending on
the purpose, and includes, for example, azo based or diazo based
polymerization initiators such as
2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile,
2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile and
azobisisobutyronitrile; and peroxide based polymerization initiators such
as benzoyl peroxide, methylethylketone peroxide, diisopropyl
peroxycarbonate, cumenehydro peroxide, 2,4-dichlorobenzoyl peroxide,
lauroyl peroxide and t-butylperoxy-2-ethylhexanoate.
[0187]The crosslinking agent is not particularly limited, can be
appropriately selected depending on the purpose, compounds mainly having
two or more polymerizable double bonds can be suitably used, and for
example, aromatic divinyl compounds such as divinyl benzene and divinyl
naphthalene; carboxylate ester having two double bonds such as ethylene
glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol
dimethacrylate; divinyl compounds such as divinyl aniline, divinyl ether,
divinyl sulfide and divinyl sulfone; and compounds having 3 or more vinyl
groups. These may be used alone or in combination of two or more.
[0188]The amount of the crosslinking agent to be added is preferably 0.01
parts by mass to 15 parts by mass relative to 100 parts by mass of the
[0189]The aqueous medium is not particularly limited, can be appropriately
selected depending on the purpose, and includes, for example water.
[0190]It is preferable that the aqueous medium contains a dispersion
[0191]As the dispersion stabilizer, for example, it is possible to use
publicly known surfactants, organic dispersants and inorganic
dispersants. Among them, the inorganic dispersant is preferable because
harmful ultrafine particles are hardly produced, the dispersion stability
is obtained by steric hindrance, thus the stability is kept even when the
reaction temperature is changed, washing is easy and no harmful effect is
given to the toner.
[0192]The inorganic dispersant includes, for example, polyvalent phosphate
metal salts such as calcium phosphate, magnesium phosphate, aluminium
phosphate, and zinc phosphate; carbonate salts such as calcium carbonate
and magnesium carbonate; inorganic salts such as calcium metasilicate,
calcium sulfate and barium sulfate; inorganic oxides such as calcium
hydroxide, magnesium hydroxide, aluminium hydroxide, silica, bentonite
[0193]The inorganic dispersant can be directly used, but in order to
obtain finer particles, the inorganic dispersant particles may be
generated and used in the aqueous medium. For example, in the case of the
calcium phosphate, water insoluble calcium phosphate can be generated by
mixing an aqueous solution of sodium phosphate and an aqueous solution of
calcium chloride under stirring at high speed, and the more homogenous
and finer dispersion becomes possible. At that time, a water soluble
sodium chloride salt is produced simultaneously. This is preferable
because when the water soluble salt is present in the aqueous medium, the
dissolution of the polymerizable monomer in water is inhibited and
ultrafine toner particles due to the emulsification polymerization are
hardly produced. However, this becomes an obstacle when the remaining
polymerizable monomer is removed at the end of the polymerization
reaction. Thus, it is preferable to exchange the aqueous medium or
perform desalting using an ion exchange resin. The inorganic dispersant
can be nearly completely removed by dissolving with acid or alkali after
the completion of the polymerization.
[0194]It is preferable that 0.2 parts by mass to 20 parts by mass of the
inorganic dispersant alone is used relative to 100 parts by mass of the
polymerizable monomer. When the inorganic dispersant is used, although
the ultrafine particles are hardly produced, the toner having the small
particle diameter is also hardly obtained. Thus it is preferable to use
0.001 parts by mass to 0.1 parts by mass of the surfactant in
[0195]The surfactant includes, for example, sodium dodecylbenzene sulfate,
sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl
sulfate, sodium oleate, sodium laurate, sodium stearate and potassium
[0196]The suspension is performed by emulsifying or dispersing the
solution or the dispersion in which the toner materials have been
uniformly dissolved or dispersed in the aqueous medium. At that time, the
toner having a sharp particle size distribution is obtained by dispersing
to the desired size of the toner particle at once using a high speed
dispersing machine such as a high speed agitator or an ultrasonic
dispersing machine.
[0197]The oil soluble polymerization initiator may be added simultaneously
with the addition of other additives in the polymerizable monomer, or may
be mixed just before suspending the solution or the dispersion of the
toner materials in the aqueous medium. Alternatively, the oil soluble
polymerization initiator dissolved in the polymerizable monomer or the
solvent can also be added during or immediately after the granulation of
the toner or before starting the polymerization reaction.
[0198]The granulation is performed by polymerizing the polymerizable
[0199]The temperature in the polymerization reaction is for example
40° C. or above, and generally 50° C. to 90° C. When
the polymerization is performed at the temperature range, the releasing
agent and the wax to be present inside the toner particle can be
precipitated by phase separation and enfolded in the particle. In order
to consume the remaining polymerizable monomer, the reaction temperature
is sometimes set at 90° C. to 150° C. However, as described
above, when heated to the temperature equal to or higher than the melting
point of the fixing aid, the resin and the fixing aid become compatible.
Thus, it is necessary to react at the temperature lower than the melting
point of the fixing aid. Specifically, it is preferable to react at
100° C. or below.
[0200]The seed polymerization method in which the polymerizable monomer is
further adsorbed to the resulting polymerized particles, and subsequently
the polymerization is performed using the oil soluble polymerization
initiator can also be used in the above granulation. At that time, the
compound having a polarity can also be dissolved or dispersed in the
polymerizable monomer to be adsorbed to use.
[0201]After the completion of the polymerization reaction, it is
preferable to stir at a stirring speed at which a particle state is kept
and suspension or precipitation of the particles is prevented using an
ordinary stirrer.
[0202]The toner particle is obtained by filtrating and washing the
polymerized particle after the completion of the polymerization reaction
to remove the redundant surfactant, drying, and further mixing with the
inorganic powder to adhere onto the particle surface. At that time, it is
preferable to remove rough powders and fine powders by classifying.
[Fine Organic Silicone Particle]
[0203]The organic silicone fine particle of the present invention is made
of a hemispheric polysiloxane cross-linked structure. The polysiloxane
cross-linked structure is composed of two or more siloxane units selected
from the siloxane units each expressed by the following Formula 1, and
has an average siloxane unit expressed by the following Formula 2.
R1mSiO(4-m)/2 Formula 1
(wherein, R1 and R2 are organic groups having a carbon atom directly
connected to a Si atom, m is an integer and is particularly preferably
from 0 to 3, n is in particularly preferably from 0.40 to 0.77).
[0204]Among them, particularly the polysiloxane cross-linked structure
composed of a first siloxane unit of Formula 1 with m being 0 and a
second siloxane unit of Formula 1 with m being 1, and having a molar
ratio [the first siloxane unit]/[the second siloxane unit] of 23/77 to
40/60 is more preferable.
[0205]These are preferably methyl silicones (methylphenyl silicone, and in
particular dimethyl silicone where the both R1 groups are a methyl group
in Formula 1)
[0206]The organic silicone fine particles of the present invention
preferably have a volume average particle diameter obtained by
measurement according to Coulter principle of 0.05 μm to 6.0 μm.
[0207]The amount of the organic silicone fine particle to be added in the
colored particle (the toner base) is not particularly limited and can be
appropriately selected depending on the purpose.
[0208]The mechanism by which a hemispheric organic fine particle of the
present invention is produced is inferred as follows. [0209](1) By
hollowing of a particulate emulsion, hollow emulsion particles are
formed. [0210](2) When the emulsion is composed of a monomer, a
polymerization initiator is added as required to harden the surface of
the emulsion particles and to form a shell on the surface thereof, and a
hollow organic fine particles are produced. [0211](3) At the same time as
the process of (2), the temperature is adjusted so that the hollow
particles burst due to expansion of gas inside the organic fine particles
or vaporization of liquid inside the particles, and then the gas inside
the hollow particles is evacuated.
[0212]Concave hemispheric organic fine particles, which resemble deflated
rubber balls, are possibly obtained by allowing hollow organic fine
particles to burst under relatively mild conditions.
[0213]Not all the hollow organic fine particles yield such hemispheric
organic fine particles, however, the hemispheric organic fine particles
can be easily separated from indefinitely formed is particles resulting
from complete burst by air classification treatment, because of the
difference in behavior as powders.
[0214]To obtain a hemispheric organic silicone fine particle, the
following method can be used, as is described in Examples of the present
invention. The method is consisted of at least [0215](A) adding step, in
the presence of at least one type of hydrolysis catalyst (a surfactant is
added as required), of a compound represented by a formula of SiX4
and a compound represented by a formula of RSiY3 (wherein X and Y
are independently, C1-C4 alkoxy group, alkoxyethoxy group containing
C1-C4 alkoxy group, C2-C4 acyloxy group, N,N-dialkylamino group
containing C1-C4 alkyl group, hydroxyl group, halogen atom or hydrogen
atom, and R is an organic group containing a carbon atom directly bound
to the silicon atom) into an aqueous medium, and [0216](B) contacting
step of the mixture obtained from the adding step (A) with an aqueous
solution containing at least one type of polymerized catalyst (a
surfactant is added as required) at a temperature in the range of
30° C. to 80° C., for at least 2 hr.
[0217]By introducing a polymerized catalyst, under a basic condition and
at a low temperature, to the mixture obtained at the adding step (A), a
hollow hemisphere like a bowl with a round bottom is formed.
[0218]To obtain further hemispheric fine particles made of materials other
than organic silicone, the method with steps (1) to (3) described above
[0219]The following method can be used as a further generalized method
applicable to various materials to form hollow emulsion particles.
[0220]According to Henry's law, solubility of a gas in a liquid is
proportional to the pressure of the gas. According to this
characteristic, when emulsion particles under pressurization containing
liquid fine particles in which gases are dissolved by pressure are
depressurized to normal pressure, air bubbles are generated in the liquid
fine particles making up the emulsion particles, and hollow emulsion
particles are formed.
[0221]After such hollow emulsion particles are formed, a polymerization
initiator is added to make shells of the particles. Hollow organic fine
particles are thus obtained. Then by appropriately adjusting the
temperature and making hollow organic fine particles burst and evacuating
gases inside the hollow organic fine particles using a phenomenon of
expansion of gases inside the hollow organic fine particles or of
vaporization of liquid inside the hollow organic fine particles,
hemispheric organic fine particles can be obtained.
[0222]This method is applicable to every resin available as an external
additive for toners, because it can produce hemispheric organic fine
particles without including a polymerization step using a monomer. For
example, hollow particles of polyethylene or polyvinyl acetate are easily
formed by dissolving polyvinyl acetate or polyethylene in an organic
solvent and by using water as a dispersion medium, forming hollow
particles at the same time as hardening surfaces of the hollow particles.
Hemispheric organic fine particles are obtained from these hollow organic
fine particles, by appropriately adjusting the temperature and making
hollow organic fine particles burst and evacuating gases inside the
hollow organic fine particles using a phenomenon of expansion of gases
inside the hollow organic fine particles or of vaporization of liquid
inside the hollow organic fine particles.
[0223]Hemispheric organic fine particles can be prepared according to the
following method in addition to the above method using Henry's law.
[0224]Emulsion particles with liquid remaining inside can be prepared, by
dissolving a resin in a solvent at a concentration near the saturated
concentration, using water as a dispersion medium to form an emulsion,
and adjusting the temperature of the emulsion so that surfaces of the
emulsion particles harden. Hemispheric organic fine particles are
obtained from these emulsion particles with liquid part inside by further
heating the emulsion particles and evacuating the liquid inside.
[0225]The external additive in addition to the organic silicone fine
particle used in the present invention is not particularly limited, can
be appropriately selected depending on the purpose, and includes for
example, silica (medium, small particle diameters), titanium compounds,
alumina, cerium oxide, calcium carbonate, magnesium carbonate, calcium
phosphate, fluorine-containing resin fine particles, silica-containing
resin fine particles, and nitrogen-containing resin fine particles. These
[Titanium Compound]
[0226]Other external additive preferably contains a titanium compound, and
it is more preferable to obtain the titanium compound by reacting a part
or all of TiO(OH)2 produced by the wet system with the silane
compound or the silicone oil.
[0227]As the silane compound, a silane coupling agent is suitably used.
The silane coupling agent includes, for example, CH3Si(Cl)3,
CH3Si(OCH3)3, CH3Si(OC2H5)3,
CH3(CH2)2Si(OCH3)3,
CH3(CH2)3Si(OCH3)3,
CH3(CH2)4Si(OCH3)3,
CH3(CH2)5Si(OCH3)3,
CH3(CH2)6Si(OCH3)3,
CH3(CH2)7Si(OCH3)3,
CH3(CH2)8Si(OCH3)3,
CH3(CH2)9Si(OCH3)3,
CH3(CH2)10Si(OCH3)3,
CH3(CH2)11Si(OCH3)3,
CH3(CH2)12Si(OCH3)3,
CH3(CH2)13Si(OCH3)3,
CH3(CH2)14Si(OCH3)3,
CH3(CH2)15Si(OCH3)3,
CH3(CH2)16Si(OCH3)3,
CH3(CH2)17Si(OCH3)3,
CH3(CH2)18Si(OCH3)3,
CH3(CH2)19Si(OCH3)3,
CH3(CH2)5Si(OC2H5)3,
CH3(CH2)6Si(OC2H5)3,
CH3(CH2)7Si(OC2H5)3,
CH3(CH2)8Si(OC2H5)3,
CH3(CH2)9Si(OC2H5)3,
CH3(CH2)10Si(OC2H5)3,
CH3(CH2)11Si(OC2H5)3,
CH3(CH2)12Si(OC2H5)3,
CH3(CH2)13Si(OC2H5)3,
CH3(CH2)14Si(OC2H5)3,
CH3(CH2)15Si(OC2H5)3,
CH3(CH2)16Si(OC2H5)3,
CH3(CH2)17Si(OC2H5)3,
CH3(CH2)18Si(OC2H5)3,
CH3(CH2)19Si(OC2H5)3,
CF3Si(OCH3)3, CH3Si(NCO)3,
(CH3)2SiCl2, (CH3)2Si(OCH3)2,
(CH3)(CH3CH2)Si(OCH3)2,
(CH3)[CH3(CH2)2]Si(OCH3)2,
(CH3)[CH3(CH2)3]Si(OCH3)2,
(CH3)[CH3(CH2)4]Si(OCH3)2,
(CH3)[CH3(CH2)5]Si(OCH3)2,
(CH3)[CH3(CH2)6]Si(OCH3)2,
(CH3)[CH3(CH2)7]Si(OCH3)2,
(CH3)[CH3(CH2)8]Si(OCH3)2,
(CH3)[CH3(CH2)9]Si(OCH3)2,
(CH3)[CH3(CH2)10]Si(OCH3)2,
(CH3)[CH3(CH2)11]Si(OCH3)2,
(CH3)[CH3(CH2)12]Si(OCH3)2,
(CH3)[CH3(CH2)13]Si(OCH3)2,
(CH3)[CH3(CH2)14]Si(OCH3)2,
(CH3)[CH3(CH2)15]Si(OCH3)2,
(CH3)[CH3(CH2)16]Si(OCH3)2,
(CH3)[CH3(CH2)17]Si(OCH3)2,
(CH3)[CH3(CH2)18]Si(OCH3)2,
(CH3)[CH3(CH2)19]Si(OCH3)2,
(CH3)2Si(NCO)2, (CH3)3SiCl,
(CH3)3Si(OCH3), (CH3)3Si(OC2H5),
(CH3)2(CH3CH2)Si(OCH3),
(CH3)2[CH3(CH2)2]Si(OCH3),
(CH3)2[CH3(CH2)3]Si(OCH3),
(CH3)2[CH3(CH2)4]Si(OCH3),
(CH3)2[CH3(CH2)5]Si(OCH3),
(CH3)2[CH3(CH2)6]Si(OCH3),
(CH3)2[CH3(CH2)7]Si(OCH3),
(CH3)2[CH3(CH2)8]Si(OCH3),
(CH3)2[CH3(CH2)9]Si(OCH3),
(CH3)2[CH3(CH2)10]Si(OCH3),
(CH3)2[CH3(CH2)11]Si(OCH3),
(CH3)2[CH3(CH2)12]Si(OCH3),
(CH3)2[CH3(CH2)13]Si(OCH3),
(CH3)2[CH3(CH2)14]Si(OCH3),
(CH3)2[CH3(CH2)15]Si(OCH3),
(CH3)2[CH3(CH2)16]Si(OCH3),
(CH3)2[CH3(CH2)17]Si(OCH3),
(CH3)2[CH3(CH2)18]Si(OCH3) and
(CH3)2 [CH3(CH2)19]Si(OCH3).
[0228]The silicone oil includes, for example, dimethyl silicone oils,
methylphenyl silicone oils, chlorophenyl silicone oils, methylhydrogen
silicone oils, alkyl modified silicone oils, fluorine modified silicone
oils, polyether modified silicone oils, alcohol modified silicone oils,
amino modified silicone oils, epoxy modified silicone oils, epoxy
polyether modified silicone oils, phenol modified silicone oils, carboxyl
modified silicone oils, mercapto modified silicone oils, (meth)acryl
modified silicone oils, and α-methylstyrene modified silicone oils.
[0229]The above reaction includes the method of immersing TiO(OH)2 in
the solution of these materials and drying. The treatment with the
coupling agent includes, for example, the method of immersing
TiO(OH)2 fine particles in the solution containing the coupling
agent and drying or the method of spraying the solution containing the
coupling agent to TiO(OH)2 fine particles and drying. The amount of
the coupling agent to be adhered is preferably 0.1% by mass to 25% by
mass relative to the TiO(OH)2 fine particles. The specific gravity
of the titanium compound is preferably 2.8 to 3.6.
[0230]Furthermore, one of other external additives may be a non-spherical
amorphous silica particle. A major axis of the non-spherical amorphous
silica particles is preferably 40 nm to 180 nm and more preferably 60 nm
to 140 nm. When the major axis is less than 40 nm, due to the stress
given in a developing device, an additive itself is embedded in the
surface of the toner base particles, and can not sometimes exert an
expected function. When it exceeds 180 nm, it becomes difficult to
strongly adhere onto the surface of the toner base particles, and the
silica particles are sometimes peeled from the surface of the toner base
particles due to the stress given in the developing device.
[0231]Here, the major axis of the non-spherical amorphous silica particle
can be measured by observing an optional single particle using an
observation procedure such as SEM and TEM and processing its image.
[0232]The BET specific surface area of other external additives is
preferably 10 m2/g to 300 m2/g and more preferably 20 m2/g
to 300 m2/g.
[0233]Here, the specific surface area can be calculated according to BET
method using a specific surface area measurement apparatus ("Autosoap 1"
manufactured by Yuasa Ionics) by adsorbing nitrogen gas to a sample
surface and using a BET multipoint method.
[0234]An average particle diameter of other external additives is
preferably 10 nm to 300 nm and more preferably 10 nm to 180 nm.
[0235]A amount of other external additive in the toner is preferably 0.1%
by mass to 8.0% by mass and more preferably 0.2% by mass to 3.0% by mass.
[Method of Adding External Additives]
[0236]Here, the method of adding the organic silicone fine particle
external additive of the present invention and other external additives
to the surface of the toner base particles may be either a dry system
adding treatment or a wet system adding treatment.
[0237]In the dry system adding treatment, the external additive and the
toner base particles are mixed and the external additive is adhered to
the surface of the toner base particles.
[0238]The mixture can be performed by a publicly known mixer such as a V
type blender, HENSCHEL MIXER and a hybridizer.
[0239]A circumferential speed of a rotation body of these apparatuses is
not particularly limited, can be appropriately selected depending on the
purpose, and to disperse and immobilize onto the toner surface, it is
preferable to rotate at a slightly slow speed of about 35 m/s followed by
rotating at 35 m/s to 55 m/s.
[0240]The stirring is not particularly limited, can be appropriately
selected depending on the purpose, and is preferably performed at
[0241]In the wet system external addition, the external additive and the
toner base particles are dispersed in a aqueous medium and the external
additive is adhered to the toner particles.
[0242]In the wet system adding treatment, in the case of the dry toner,
the toner base particles before dry system adding are dispersed in water
using a surfactant if necessary. When the toner particles are formed in
water, it is preferable to remove the surfactant used by washing and
subsequently perform a wet system adding step. The excessive surfactant
present in water is removed by solid liquid separation operation such as
filtration and centrifugation, and a resulting cake or slurry is
redispersed in the aqueous medium. Furthermore, inorganic particles are
added and dispersed in the slurry. The inorganic particles can also be
previously dispersed in the aqueous medium. At that time, if dispersed
using the surfactant having a polarity opposed to a polarity of the
surfactant used for making a water dispersion of the toner base
particles, the external additive is efficiently adhered onto the toner
particle surface. When the inorganic particles have been hydrophobilized
and is hardly dispersed in a aqueous dispersion, the inorganic particles
may be dispersed by using alcohol in a small amount in combination to
reduce a surface tension and be easily wetted.
[0243]Subsequently, an aqueous solution of the surfactant having the
opposed polarity is gradually added with stirring. It is preferable to
use the surfactant having the opposed polarity at 0.01% by mass to 1% by
mass relative to the toner particle solid content. The charge of the
inorganic fine particle dispersion in water is neutralized by adding the
surfactant having the opposed polarity, and the fine inorganic particles
can be aggregated and adhered onto the toner particle surface. It is
preferable to use this inorganic fine particle at 0.01% by mass to 5% by
mass relative to the toner particle solid content. Instead of gradually
adding the solution of the surfactant having the opposed polarity with
stirring, the fine inorganic particles can be adhered by shifting pH of
the dispersion to an acid side or an alkali side.
[0244]These fine inorganic particles adhered onto the toner surface can be
immobilized on the toner surface to prevent the dissociation by
subsequently heating the slurry. At that time, it is preferable to heat
at a temperature higher than a glass transition temperature (Tg) of the
resin which composes the toner. Furthermore, a heating treatment after
drying may be performed with preventing the aggregation.
[0245]The developer of the present invention contains at least the toner
of the present invention, and contains appropriately selected other
components such as carriers. The developer may be a one-component
developer or a two component developer. When used in a high speed
printers accommodating the enhancement of data processing speeds in
recent years, the two-component developer is preferable in terms of
enhanced lifetime.
[0246]In the case of the one-component developer using the toner of the
present invention, even when the toner is consumed and supplied, the
variation of the toner particle diameters is small, and there is no
filming of the toner to the developing roller and no fusion-bond of the
toner to the member such as a blade for making the toner the thin layer.
The good and stable developing properties and images are obtained in the
long term use (stirring) of the developing device. In the case of the
two-component developer using the toner of the present invention, even
when the toner is consumed and supplied for a long time, the variation of
the toner particle diameters during the development is small. The good
and stable developing properties are obtained in the long term stirring
in the developing device.
[0247]The carrier is not particularly limited, can be appropriately
selected depending on the purpose, and those having a core material and a
resin layer which covers the core material are preferable.
[0248]Materials for the core material are not particularly limited, can be
appropriately selected from those known publicly, and for example, 50
emu/g to 90 emu/g of manganese-strontium (Mn--Sr) based materials and
manganese-magnesium (Mn--Mg) based materials are preferable. In terms of
assuring the image density, highly magnetized materials such as an iron
powder (100 emu/g or more) and magnetite (75 emu/g to 120 emu/g) are
preferable. In terms of being advantageous for making a high image
quality because contact to the photoconductor on which the toner stands
like ears can be weakened, weakly magnetized materials such as
copper-zinc (Cu--Zn) based materials (30 emu/g to 80 emu/g) are also
preferable. These may be used alone or in combination of two or more.
[0249]The particle diameter of the core material is preferably 10 μm to
150 μm and more preferably 40 μm to 100 μm in the volume average
[0250]When the average particle diameter (volume average particle diameter
(D50)) is less than 10 μm, the fine powder is increased in the
distribution of carrier particles, and magnetization per particle becomes
low to sometimes cause carrier scattering. When it exceeds 150 μm, the
specific surface area is reduced to sometimes cause toner scattering. In
a full color printing where solid portions are abundant, reproducibility
of the solid portions is sometimes degraded.
[0251]Materials of the resin layer is not particularly limited, can be
appropriately selected from publicly known resins depending on the
purpose, and includes, for example, amino based resins, polyvinyl based
resins, polystyrene based resins, halogenated olefin resins, polyester
based resins, polycarbonate based resins, polyethylene resins, polyvinyl
fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene
resins, polyhexafluoropropylene resins, copolymers of vinylidene fluoride
and acryl monomer, copolymers of vinylidene fluoride and vinyl fluoride,
fluoro terpolymers such as terpolymers of tetrafluoroethylene and
vinylidene fluoride and non-fluoride monomer, and silicone resins. These
[0252]The amino based resins include, for example, urea-formaldehyde
resins, melamine resins, benzoguanamine resins, urea resins, polyamide
resins and epoxy resins. The polyvinyl based resins include, for example,
acryl resins, polymethyl methacrylate resins, polyacrylonitrile resins,
polyvinyl acetate resins, polyvinyl alcohol resins and polyvinyl butyral
resins. The polystyrene based resins include, for example, polystyrene
resins and styrene acryl copolymer resins. The halogenated olefin resins
include, for example, polyvinyl chloride. The polyester based resins
include, for example, polyethylene terephthalate resins and polybutylene
[0253]If necessary, conductive powders may be contained in the resin
layer. The conductive powders include, for example, metal powders, carbon
black, titanium oxide, tin oxide, and zinc oxide. The average particle
diameter of these conductive powders is preferably 1 μm or less. When
the average particle diameter exceeds 1 μm, it sometimes becomes
difficult to control electric resistance.
[0254]The resin layer can be formed by dissolving the silicone resin in
the solvent to prepare a coating solution, uniformly applying the coating
solution on the surface of the core material by a publicly known
application method, and drying followed by baking. The application method
includes, for example, a dipping method, a spray method and a blush
[0255]The solvent is not particularly limited, can be appropriately
selected depending on the purpose, and includes, for example, toluene,
xylene, methylethylketone, methyl isobutyl ketone, cellsolve and butyl
[0256]The baking is not particularly limited, may be an external heating
system or an internal heating system, and includes the methods using a
fixed electric furnace, a fluidal electric furnace, a rotary electric
furnace, and a burner furnace, and the method using microwave.
[0257]The amount of the resin layer in the carrier is preferably 0.01% by
mass to 5.0% by mass. When the amount is less than 0.01% by mass, no
uniform resin layer can be sometimes formed on the surface of the core
material. When it exceeds 5.0% by mass, the resin layer becomes so thick
that it causes the granulation of carrier particles one another, and no
uniform carrier particles can be sometimes obtained.
[0258]When the developer is the two-component developer, the amount of the
carrier in the two-component developer is not particularly limited, can
be appropriately selected depending on the purpose, and for example, is
preferably 90% by mass to 98% by mass and more preferably 93% by mass to
97% by mass.
[0259]The developer of the present invention contains the toner,
therefore, combines the excellent cleaning ability, image quality and
durability, and can stably form images with a high quality.
[0260]The developer of the present invention can be suitably used for the
image formation by publicly known various electrographic methods such as
magnetic one-component developing methods, non-magnetic one-component
developing methods, and two-component developing methods, and
particularly can be suitably used for the following process cartridge and
image forming method of the present invention.
[0261]The process cartridge of the present invention has a photoconductor
and a developing unit as an integrated unit, and further may include at
least one image processing unit selected from a charging unit, a
transferring unit, a cleaning unit and a charge eliminating unit, wherein
the developing unit has the toner or the developer of the present
invention in the process cartridge detachably mounted on the main body of
[0262]The developing unit has at least a developer housing device which
houses the toner or the developer of the present invention and a
developer bearing member which bears and feeds the toner or the developer
housed in the developer housing device, and further may have a layer
thickness regulatory member for regulating a layer thickness of the toner
[0263]The process cartridge of the present invention can be attached
detachably to various electrographic apparatuses, and it is preferable to
attach detachably to the image forming apparatus of the present invention
[0264]Here, the process cartridge, for example, as shown in FIG. 1,
builds-in the photoconductor 101, contains a charge unit 102, a
developing unit 104, a transferring unit 108 and a cleaning unit 107, and
further has the other members if necessary. In FIG. 1, 103 represents the
exposure by the exposing unit, and a light source capable of writing at
high resolution is used. In FIG. 1, 105 represents the recording medium.
As the photoconductor 101, the same one as in the image forming apparatus
described later can be used. An optional charging member is used for the
charging unit 102.
[0265]Subsequently, in the image formation process by the process
cartridge shown in FIG. 1, as the photoconductor 101 rotates in an arrow
direction, the latent electrostatic image corresponding to an exposure
image is formed on its surface by charge by the charging unit 102 and the
exposure 103 by the exposing unit (not shown in the figure). This latent
electrostatic image is developed with the toner in the developer of the
present invention in the developing unit 104, the toner image is
transferred onto the recording medium 105 by the transferring unit 108
and printed out. Subsequently, the photoconductor surface after the
transfer of the image is cleaned by the cleaning unit 107, and its
electricity is removed by the charge eliminating unit (not shown in the
figure). The above operation is repeated again.
[0266]The image forming method of the present invention includes at least
a latent electrostatic image forming step, a developing step, a
transferring step, and a fixing step, preferably includes a cleaning
step, and further includes other steps appropriately selected as needed
such as an electricity removing step, a recycling step and a controlling
[0267]The image forming apparatus of the present invention has at least a
latent electrostatic image bearing member, a latent electrostatic image
forming unit, a developing unit, a transferring unit, and a fixing unit,
preferably has a cleaning unit, and further has other units appropriately
selected as needed such as a charge eliminating unit, a recycling unit,
and a controlling unit.
[0268]The image forming method of the present invention can be suitably
carried out by the image forming apparatus of the present invention, the
latent electrostatic image forming step can be performed by the latent
electrostatic image forming unit, the developing step can be performed by
the developing unit, the transferring step can be performed by the
transferring unit, the fixing step can be performed by the fixing unit,
and the other step can be performed by the other unit.
[Latent Electrostatic Image Forming Step and Latent Electrostatic Image
Forming Unit]
[0269]The latent electrostatic image forming step is a step of forming the
latent electrostatic image on the latent electrostatic image bearing
[0270]In the latent electrostatic image bearing member (sometimes referred
to as a "light conductive insulator" or a "photoconductor"), its
material, shape, structure, and size are not particularly limited, and
can be appropriately selected from those known publicly. Its shape
suitably includes a drum shape, and its material includes inorganic
photoconductors such as amorphous silicon and serene and organic
photoconductors such as polysilane and phthalopolymethine. Among them,
amorphous silicon is preferable in terms of long lifetime.
[0271]The latent electrostatic image can be formed, for example, by evenly
charging the surface of the photoconductor (the latent electrostatic
image bearing member) and subsequently exposing like the image, and can
be formed by the latent electrostatic image forming unit. The latent
electrostatic image forming unit is, for example, equipped with at least
a charging device which evenly charges the surface of the latent
electrostatic image bearing member and an exposing device which exposes
the surface of the latent electrostatic image bearing member like the
[0272]The charging can be performed, for example using the charging device
by applying voltage onto the surface of the latent electrostatic image
[0273]The charging device is not particularly limited, can be
example, a publicly known contact charging device equipped with a
conductive or semi-conductive roll, brush, film, or rubber blade, and a
non-contact charging device utilizing corona discharge, e.g., a corotron
and scorotron.
[0274]The exposure, for example, can be performed by exposing the surface
of the latent electrostatic image bearing member like the image using the
exposing device.
[0275]The exposing device is not particularly limited as long as the
exposure can be performed like the image to be formed on the surface of
the latent electrostatic image bearing member charged by the charging
device, can be appropriately selected depending on the purpose, and
includes, for example, various exposing devices, e.g., a copy optical
system, a rod lens array system, a laser optical system, and a liquid
crystal shutter optical system.
[0276]A light backside method of exposing from the backside of the latent
electrostatic image bearing member may be employed in the present
[0277]The developing step is a step of forming the visible image by
developing the latent electrostatic image using the toner or the
developer of the present invention.
[0278]The visible image can be formed, for example, by developing the
latent electrostatic image using the toner or the developer of the
present invention, and can be formed by the developing unit.
[0279]The developing unit is not particularly limited as long as the
development can be performed using the toner or the developer of the
present invention, can be appropriately selected from those known
publicly, and suitably includes those having at least a developing device
which houses the toner or the developer of the present invention and can
impart the toner or the developer to the latent electrostatic image in
contact or in no contact with it. The developing device equipped with the
vessel containing the toner of the present invention is more preferable.
[0280]The developing device may employ a dry developing system or a wet
developing system, or may be a monochromatic developing device or a
multicolor developing device. For example, one having a stirring device
which charges by frictionizing and stirring the toner or the developer
and a rotatable magnet roller are suitably included.
[0281]In the developing device, for example, the toner and the carrier are
mixed and stirred, the toner is charged by friction at that time and kept
in the ear-standing state on the surface of the rotating magnet roller to
form a magnetic brush. The magnet roller is disposed in the vicinity of
the latent electrostatic image bearing member (photoconductor). Thus, a
part of the toner which composes the magnetic brush formed on the surface
of the magnet roller migrates to the surface of the latent electrostatic
image bearing member (photoconductor) by an electrically attracting
force. As a result, the latent electrostatic image is developed by the
toner and the visible image is formed on the surface of the latent
electrostatic image bearing member (photoconductor) by the toner.
[0282]The developer housed in the developing device is a developer
containing the toner of the present invention, and the developer may be a
one-component developer or a two-component developer. The toner contained
in the developer is the toner of the present invention.
[0283]The transferring step is a step of transferring the visible image
onto a recording medium. It is preferable that using an intermediate
transferring member, the visible image is primarily transferred onto the
intermediate transferring member and subsequently the visible image is
secondarily transferred onto the recording medium. Using as the toner,
the toner having two or more colors and preferably full color toner, it
is more preferable to have a primary transferring step in which the
visible image is transferred onto the intermediate transferring member to
form a composite transfer image and a secondary transferring step in
which the composite transfer image is transferred onto the recording
[0284]The transfer can be performed by charging the visible image from the
latent electrostatic image bearing member (photoconductor) using a
transfer charging device, and can be performed by the transferring unit.
A preferable aspect is that the transferring unit has a primary
transferring unit in which the visible image is transferred onto the
intermediate transferring member to form the composite transfer image and
a secondary transferring unit in which the composite transfer image is
transferred onto the recording medium.
[0285]The intermediate transferring member is not particularly limited,
can be appropriately selected from those known publicly depending on the
purpose, and suitably includes, for example, a transfer belt.
[0286]It is preferable that the transferring unit (the primary
transferring unit, the secondary transferring unit) has a transferring
device which peels and charges the visible image formed on the latent
electrostatic image bearing member (photoconductor) to the side of the
recording medium. There may be one transferring unit or multiple
transferring units. The transferring device includes a corona
transferring device by corona discharge, the transfer belt, a transfer
roller, a pressure transfer roller, and an adhesion transferring device.
The recording medium is not particularly limited, and can be
appropriately selected from the recording media (recording papers) known
[0287]The fixing step is a step of fixing the visible image transferred
onto the recording medium using the fixing unit. Each color toner may be
fixed every transfer onto the recording medium, or respective toners may
be laminated and then fixed all at once.
[0288]The fixing unit is not particularly limited, can be appropriately
selected depending on the purpose, and heating pressurizing units known
publicly are suitable. The heating pressurizing units include the
combination of a heating roller and a pressurizing roller and the
combination of the heating roller, the pressurizing roller, and an
[0289]The heating in the heating pressurizing unit is preferably to be at
80° C. to 200° C. typically.
[0290]In the present invention, depending on the purpose, together with or
in place of the fixing step and the fixing unit, a light fixing device
known publicly, for example, may be used.
[0291]The electricity removing step is a step of removing the electricity
by applying an electricity removing bias to the latent electrostatic
image bearing member, and can be suitably performed by the charge
eliminating unit.
[0292]The charge eliminating unit is not particularly limited, may be able
to apply the electricity removing bias to the latent electrostatic image
bearing member, can be appropriately selected from electricity removing
devices known publicly, and suitably includes, for example, an charge
eliminating lamp.
[0293]The cleaning step is a step of removing the toner for electrographs
left on the latent electrostatic image bearing member, and can be
suitably performed using the cleaning unit.
[0294]The cleaning unit is not particularly limited, may be able to remove
the toner for electrographs left on the latent electrostatic image
bearing member, can be appropriately selected from publicly known
cleaners, and suitably includes, for example, a magnetic brush cleaner,
an electrostatic brush cleaner, a magnetic roller cleaner, a blade
cleaner, a brush cleaner, and a web cleaner.
[0295]The recycling step is a step of recycling the toner removed in the
cleaning step in the developing unit, and can be suitably performed using
the recycling unit.
[0296]The recycling unit is not particularly limited, and includes
publicly known feeding units.
[0297]The controlling step is a step of controlling respective steps, and
can be suitably performed using the controlling unit.
[0298]The controlling unit is not particularly limited as long as it can
control the operation of each unit, can be appropriately selected
depending on the purpose, and includes, for example, equipments such as
sequencers and computers.
[Image Forming Apparatus Example 1]
[0299]One example of the image forming apparatus appropriate for
performing the image forming method of the present invention will be
described with reference to FIG. 2. The image forming apparatus 100 shown
in FIG. 2 is equipped with a photoconductor drum 10 (hereinafter
sometimes referred to as the "photoconductor 10") as the latent
electrostatic image bearing member, a charging roller 20 as the charging
unit, an exposer 30 as the exposing unit, a developing device 40 as the
developing unit, an intermediate transferring member 50, a cleaning
device 60 as the cleaning unit having a cleaning blade, and an charge
eliminating lamp 70 as the charge eliminating unit.
[0300]The intermediate transferring member 50 is an endless belt, and is
tightly stretched with three rollers 51 disposed in the endless belt so
as to move in an arrow direction. A part of three rollers 51 also
functions as a transfer bias roller which can apply a given transfer bias
(primary transfer bias) to the intermediate transferring member 50. The
cleaning device 90 having the cleaning blade is disposed in the vicinity
of the intermediate transferring member 50. A transferring roller 80 is
oppositely disposed as the transferring unit which can apply the transfer
bias to transfer (secondary transfer) a developed image (toner image)
onto a transfer paper 95 as a final transfer material. In a surrounding
area of the intermediate transferring member 50, the corona charging
device 58 for imparting the charge to the toner image on the intermediate
transferring member 50 is disposed in a rotation direction of the
intermediate transferring member 50, between a contact section of the
photoconductor 10 with the intermediate transferring member 50 and a
contact section of the intermediate transferring member 50 with a
transfer paper 95.
[0301]The developing device 40 is composed of a developing belt 41 as the
developer bearing member and a black developing unit 45K, a yellow
developing unit 45Y, a magenta developing unit 45M and a cyan developing
unit 45C arranged together around the developing belt 41. The black
developing unit 45K is equipped with a developer housing section 42K, a
developer supplying roller 43K, and a developing roller 44K, the yellow
developing unit 45Y is equipped with a developer housing section 42Y, a
developer supplying roller 43Y, and a developing roller 44Y, the magenta
developing unit 45M is equipped with a developer housing section 42M, a
developer supplying roller 43M, and a developing roller 44M, and the cyan
developing unit 45C is equipped with a developer housing section 42C, a
developer supplying roller 43C, and a developing roller 44C. The
developing belt 41 is an endless belt and tightly stretched with multiple
belt rollers rotatably, and a part thereof is contacted with the
photoconductor 10.
[0302]In the image forming apparatus 100 shown in FIG. 2, for example, the
charging roller 20 charges the photoconductor drum 10 evenly. The
photoconductor drum 10 is exposed using the exposer 30 to form the latent
electrostatic image. The latent electrostatic image formed on the
photoconductor drum 10 is developed by supplying the toner from the
developing device 40 to form the visible image (toner image). The visible
image (toner image) is transferred onto the intermediate transferring
member 50 (primary transfer) by voltage applied from the roller 51, and
further transferred onto the transfer paper 95 (secondary transfer). As a
result, the transfer image is formed on the transfer paper 95. The toner
remaining on the photoconductor 10 is removed by the cleaning device 60,
and the charge on the photoconductor 10 is once removed by the charge
eliminating lamp 70.
[0303]In the image forming apparatus and the image forming method of the
present invention, a high image quality is efficiently obtained, because
they use the toner of the present invention which combines an excellent
cleaning ability, image quality, and durability.
[Image Forming Apparatus Example 2]
[0304]Another aspect of performing the image forming method of the present
invention will be described with reference to FIG. 3. The image forming
apparatus shown in FIG. 3 has the same constitution and exhibits the same
action effects as in the image forming apparatus 100 shown in FIG. 2,
except that instead of including the developing device 40 in the image
forming apparatus shown in FIG. 2 the image forming apparatus shown in
FIG. 3 is directly oppositely disposing the black developing unit 45K,
the yellow developing unit 45Y, the magenta developing unit 45M, and the
cyan developing unit 45C around the photoconductor 10. In FIG. 3 and also
in FIG. 4 described below, those constituents which were the same as the
constituents of the image forming apparatus shown in FIG. 2 were
represented by the same signs and their description are omitted.
[Image Forming Apparatus Example 3]
[0305]Another aspect of performing the image forming method of the present
invention will be described with reference to FIG. 4. An image forming
apparatus shown in FIG. 4 is a tandem type color image forming apparatus.
The image forming apparatus is equipped with a copy apparatus main body
150, a paper supply table 200, a scanner 300, and an automatic draft
feeding (ADF) apparatus 400.
[0306]In the copy apparatus main body 150, an endless belt-shaped
intermediate transferring member 50 is provided in a central section.
And, the intermediate transferring member 50 is tightly stretched with
support rollers 14, 15 and 16 and is rotatable clockwise. A cleaning
device 17 to remove the residual toner remaining on the intermediate
transferring member 50 is disposed in the vicinity of the support roller
15. An image forming unit 120 in which 4 image forming components 18 of
yellow, cyan, magenta, and black have been oppositely arranged together
is disposed to the intermediate transferring member 50 tightly stretched
with the support rollers 14 and 15, along a feeding direction thereof. In
the vicinity of the image forming unit 120, the exposer 30 is disposed. A
secondary transferring apparatus 22 is disposed at the side of the
intermediate transferring member 50 opposite to the side at which the
image forming unit 120 is disposed. In the secondary transferring
apparatus 22, a secondary transfer belt 24 which is the endless belt is
tightly stretched with a pair of support rollers 23, and the recording
paper fed on the secondary transfer belt 24 can be mutually contacted
with the intermediate transferring member 50. In the vicinity of the
secondary transferring apparatus 22, the fixing apparatus 25 is disposed.
The fixing apparatus 25 is equipped with a fixing belt 26 which is an
endless belt and a pressurizing roller 27 disposed by press-pushing by
the fixing belt 26.
[0307]In the vicinity of the secondary transferring apparatus 22 and the
fixing apparatus 25, a sheet reversing apparatus 28 which reverses the
recording paper to form the images on both sides of the recording paper
[0308]Next, the formation of the full color image (color copy) using the
image forming unit 120 will be described. First, a draft is set on a
draft table 130 of the automatic draft feeding apparatus (ADF) 400, or
alternatively the automatic draft feeding apparatus 400 is opened, the
draft is set on a contact glass 32 of the scanner 300 and the automatic
draft feeding apparatus 400 is closed.
[0309]When a start switch (not shown in the figure) is pressed, after
feeding the draft onto the contact glass 32 when the draft has been set
in the automatic draft feeding apparatus 400, or immediately when the
draft has been set on the contact glass 32, the scanner is driven, and a
first carriage 33 and a second carriage 34 run. At that time, the light
from the light source is irradiated as well as the reflection light from
a draft side irradiated from the first carriage is reflected at a mirror
in the second carriage 34, and received by a reading sensor 36 through an
imaging lens 35. By this operation, a draft is read out to generate image
information of respective colors of black, yellow, magenta, and cyan.
Each image information is then transmitted to respective image forming
components 18 in the image forming unit 120 to form the visible images of
respective colors of black, yellow, magenta, and cyan in each image
forming component.
[0310]The present invention will be further described in detail below with
reference to Examples. However, embodiments of the present invention are
not limited to the disclosed ones. Note that "parts" and % indicate
"parts by weight" and "% by weight", respectively.
[0311]First, a toner, a carrier, and a two-component developer composed of
the toner and carrier used in the Examples will be described.
[0312]Toners used in the Example were prepared by the method described
--Synthesis of Organic Fine Particle Emulsion--
[0313]Into a reaction vessel equipped with a stirring bar and a
thermometer, 683 parts of water, 11 parts of sodium salt of methacrylic
acid ethylene oxide adduct sulfate ester (ELEMINOL RS-30 manufactured by
Sanyo Chemical Industries, Ltd.), 83 parts of styrene, 83 parts of
methacrylic acid, 110 parts of butyl acrylate and 1 part of ammonium
persulfate were added, and the mixture was stirred at 400 rpm for 15
minutes to yield a white liquid emulsion. The temperature of the reaction
system was raised up to 75° C. by heating, and the reaction was
performed for 5 hours. Then, 30 parts of an aqueous solution of 1%
ammonium persulfate was added, and the reaction system was matured at
75° C. for 5 hours to yield an aqueous dispersion of vinyl based
resin (copolymer of sodium salt of styrene-methacrylic acid-butyl
acrylate-methacrylic acid ethylene oxide adduct sulfate ester) [fine
particle dispersion 1].
[0314]The weight average particle diameter of the resulting [fine particle
dispersion 1] measured by LA-920 was 105 nm. A part of the [fine particle
dispersion 1] was dried to isolate a resin component. The glass
transition temperature of the resin component was 59° C., and the
weight average molecular weight was 150,000.
[0315]Water (990 parts), 83 parts of [fine particle dispersion 1], 37
parts of an aqueous solution of 48.5% sodium dodecyldiphenyl ether
disulfonate (ELEMINOL MON-7 manufactured by Sanyo Chemical Industries,
Ltd.), and 90 parts of ethyl acetate were mixed and stirred to yield a
milky white liquid. This was called as [aqueous phase 1].
--Synthesis of Low Molecular Polyester--
[0316]In a reaction vessel equipped with a condenser tube, a stirrer and a
nitrogen inlet tube, 229 parts of bisphenol A ethylene oxide 2 mol
adduct, 529 parts of bisphenol A propylene oxide 3 mol adduct, 208 parts
of terephthalic acid, 46 parts of adipic acid and 2 parts of dibutyltin
oxide were added, and reacted under atmospheric pressure at 230°
C. for 8 hours. The reaction was performed under reduced pressure of 10
mmHg to 15 mmHg for 5 hours. Then, 44 parts of trimellitic acid anhydrate
were added into the reaction vessel, and the reaction was continued at
180° C. under atmospheric pressure for 2 hours to yield [low
molecular polyester 1].
[0317]The resulting [low molecular polyester 1] had a number average
molecular weight of 2,500, a weight average molecular weight of 6,700, a
Tg of 43° C. and an acid value of 25.
--Synthesis of Intermediate Polyester and Prepolymer--
[0318]In a reaction vessel equipped with a condenser tube, a stirrer and a
nitrogen inlet tube, 682 parts of bisphenol A ethylene oxide 2 mol
adduct, 81 parts of bisphenol A propylene oxide 2 mol adduct, 283 parts
of terephthalic acid, 22 parts of trimellitic acid anhydrate and 2 parts
of dibutyltin oxide were added, and reacted under atmospheric pressure at
230° C. for 8 hours. Then, the reaction was performed under
reduced pressure of 10 mmHg to 15 mmHg for 5 hours to yield [intermediate
polyester 1]. The resulting [intermediate polyester 1] had a number
average molecular weight of 2,100, a weight average molecular weight of
9,500, a Tg of 55° C., an acid value of 0.5 and a hydroxyl group
value of 51.
[0319]Subsequently, in a reaction vessel equipped with a condenser tube, a
stirrer and a nitrogen inlet tube, 410 parts of the [intermediate
polyester 1], 89 parts of isophorone diisocyanate and 500 parts of ethyl
acetate were placed, and reacted at 100° C. for 5 hours to yield
[prepolymer 1]. The free isocyanate content of the [prepolymer 1] was
[0320]In a reaction vessel equipped with a stirring bar and a thermometer,
170 parts of isophorone diamine and 75 parts of methylethylketone were
added, and reacted at 50° C. for 5 hours to yield a [ketimine
compound 1]. The amine value of the resulting [ketimine compound 1] was
[0321]Water (35 parts), 40 parts of phthalocyanine a pigment (FG7351
manufactured by Toyo Ink Mfg. Co., Ltd.) and 60 parts of polyester resin
(RS801 manufactured by Sanyo Chemical Industries, Ltd.) were mixed using
HENSCHEL MIXER (manufactured by Mitsui Mining Co., Ltd.), the resulting
mixture was kneaded at 150° C. for 30 minutes using two rolls,
subsequently pressure rolled and cooled, and then pulverized by a
pulverizer to yield [master batch 1].
[0322]In a reaction vessel equipped with a stirring bar and a thermometer,
378 parts of the [low molecular polyester 1], 110 parts of carnauba wax,
22 parts of CCA (salicylate metal complex E-84 manufactured by Orient
Chemical Industries Ltd.) and 947 parts of ethyl acetate were added, the
temperature was raised to 80° C. under stirring, and the
temperature was kept for 5 hours, and then cooled to 30° C. in one
hour. Then, 500 parts of the [master batch 1] and 500 parts of ethyl
acetate were placed in the vessel, and mixed for one hour to yield [raw
material solution 1].
[0323]The resulting [raw material solution 1] (1,324 parts) was
transferred to another vessel, and using a bead mill (ULTRAVISCOMILL
manufactured by Imex), carbon black and wax were dispersed under
conditions of a liquid sending speed of 1 kg/hr, a disc circumferential
speed of 6 m/second, filled with 80% by volume of 0.5 mm zirconium beads
and 3 passes. Subsequently, 1,324 parts of a 65% ethyl acetate solution
of [low molecular polyester 1] was added, and the reaction system was
dispersed once using the bead mill under the above conditions to yield
[pigment-wax dispersion 1]. The solid content concentration (130°
C., 30 minutes) of the resulting [pigment-wax dispersion 1] was 50%.
--Emulsification--
[0324]In a vessel, 648 parts of the [pigment-wax dispersion 1], 154 parts
of the [prepolymer 1] and 6.6 parts of the [ketimine compound 1] were
poured, and mixed at 5,000 rpm for one minutes using T.K. HOMOMIXER
(manufactured by Tokushu Kika Kogyo Co., Ltd.). Then, 1,200 parts of the
[aqueous phase 1] was added to the vessel, the mixture was mixed at
13,000 rpm for 20 minutes using T.K. HOMOMIXER to yield [emulsified
slurry 1].
--Shape Control--
[0325]Appropriate amounts of ion-exchange water, an activating agent, and
a thickener were poured in a vessel and stirred. Into this aqueous
solution, the [emulsified slurry 1] was added, and the components were
mixed at 2,000 rpm for one hour using T.K. HOMOMIXER (manufactured by
Tokushu Kika Kogyo Co., Ltd.) to yield [shape controlled slurry 1].
[0326]In a vessel equipped with a stirrer and a thermometer, the [shape
controlled slurry 1] was poured, the [shape control slurry 1] was
subjected to a desolvation treatment at 30° C. for 8 hours, and
the matured at 45° C. for 4 hours to yield [dispersion slurry 1].
[0327]The [dispersion slurry 1] (100 parts) was filtrated under reduced
pressure, and subsequently washed and dried as follows.
[0328](1) Ion exchange water (100 parts) was added to a filter cake, which
was then mixed using T.K. HOMOMIXER (12,000 rpm for 10 minutes) and
subsequently filtrated.
[0329](2) An aqueous solution (100 parts) of 10% sodium hydroxide was
added to the filter cake of (1), which was then mixed using T.K.
HOMOMIXER (12,000 rpm for 30 minutes) and subsequently filtrated under
[0330](3) Ten percent by weight hydrochloric acid (100 parts) was added to
the filter cake of (2), which was then mixed using T.K. HOMOMIXER (12,000
rpm for 10 minutes) and subsequently filtrated.
[0331](4) Ion exchange water (300 parts) was added to the filter cake of
(3), which was then mixed using T.K. HOMOMIXER (12,000 rpm for 10
minutes) and subsequently filtrated. The filtration of (4) was repeated
twice to yield [filter cake 1].
[0332]The [filter cake 1] thus obtained was dried at 45° C. for 48
hr using an air circulating drier, and sieved through a 75 μm-mesh
screen to thereby yield final [toner base particle A].
[0333]The carrier used in the following Examples and Comparative Examples
was prepared as follows. First, 200 parts of a silicone resin solution
(manufactured by Shin-Etsu Chemical Co., Ltd.) and 3 parts of carbon
black (manufactured by Cabot) were dissolved and dispersed to obtain a
coating solution. Then, the coating solution was applied over the surface
of 2500 parts of a ferrite core material by a fluidized-bed spray method
to coat the core material surface, and then the core material coated with
the coating solution was baked in an electric furnace at 300° C.
for 2 hours to yield a silicon resin-coated carrier. For the carrier
particle diameter, it is preferable to use a carrier having a relatively
sharp particle diameter distribution and an average particle diameter of
30 μm to 60 μm. Such a carrier was used in the following Example
Synthesis of Fine Organic Silicone Particle A
[0334]Ion-exchange water (400 g) was poured into a reaction vessel and 0.2
g of a 48% aqueous solution of sodium hydroxide was added. Into this
aqueous solution, 47 g of methyl trimethoxy silane and 48 g of
tetraethoxy silane were added and a hydrolysis reaction of them was
performed for an hour with the reaction temperature kept at 13° C.
to 15° C. Then, 1.8 g of a 10% aqueous solution of sodium
dodecylbenzensulfonate was further added and a hydrolysis reaction was
performed for 3 hours at the same temperature to yield a transparent
reactant containing a silanol compound in a total of 4 hours. Then, the
reactant thus obtained was subjected to a condensation reaction for 5
hours with the reaction temperature kept at 30° C. to 80°
C. to yield an aqueous suspension containing a fine organic silicone
particle. This aqueous suspension was filtered through a membrane filter,
the filtrate was subjected to centrifugation to isolate white fine
particles. The white fine particles thus isolated were washed with water
and subjected to a hot-air drying at 150° C. for 5 hours to yield
30 g of a fine organic silicone particle A.
[0335]The organic silicone fine particle A was observed by a scanning
electron microscope and found that this fine organic silicone particle A
had a hollow hemispherical body, was an organic silicone fine particle
having an average diameter of 1.43 μm in a cross-section of the
spherical surface, and was composed of a polysiloxane cross-linked
structure with a molar ratio of the siloxane unit represented by Formula
1 to the siloxane unit represented by Formula 2 of 40/60 determined by
elemental analysis, ICP emission spectroscopic analysis, and FT-IR
[0336]With respect to the particles thus obtained, the average particle
diameter (μm) was measured using COULTER MULTISIZER II (manufactured
by COULTER COMPANY LIMITED) and a diameter calculated based on a weight
distribution was adopted. Into the toner base particles A, 1.0% of this
hemispheric organic fine particles A was added and mixed using a HENSCHEL
MIXER at a circumferential speed of stirring blades of 20 m/s, and then,
into this mixture, 0.8 parts of isobutyl-treated hydrophobic titanium
oxide having an average diameter of 15 nm and 1.0 part of
hexamethyldisilazane-treated hydrophobic silica having an average
particle diameter of 12 nm were added and mixed using a HENSCHEL MIXER at
a circumferential speed of stirring blades of 20 m/s to obtain toner A.
[0337]Following a procedure similar to Example 1, 400 g of ion-exchange
water was poured into a reaction vessel, 0.35 g of a 48% aqueous solution
of sodium hydroxide and 0.15 g of a 20% aqueous solution of
α-(p-nonylphenyl)-ω-hydroxy (polyoxyethylene) (number of
oxyethylene units=10) were added, and the resultant solution was stirred
sufficiently to produce a homogenous solution. With the temperature of
this aqueous solution kept at 14° C., into this aqueous solution,
a monomer mixture of 31 g of methyl trimethoxy silane, 28.4 g of
3-metacryloxypropyl trimethoxy silane, and 47.5 g of tetraethoxy silane
was gradually delivered by drops so as not to mix the aqueous solution
and the monomer layer, after completion of the dropping, the aqueous
solution and the monomer layer were slowly stirred in a laminar flow
state maintaining both layers. After one hour, 1.7 g of a 10% aqueous
solution of sodium dodecylbenzensulfonate was added and stirred slowly as
before further for 3 hours at 14° C. Then the reactant thus
obtained was further subjected to a condensation reaction for 5 hours at
30° C. to 80° C. to yield an aqueous suspension containing
a fine organic silicone particle. This aqueous suspension was filtered
through a membrane filter, the filtrate was subjected to centrifugation
to isolate white fine particles. The white fine particles thus isolated
were washed with water and subjected to hot-air drying at 150° C.
for 5 hours to yield 35 g of fine organic silicone particle B.
[0338]The measurement and analysis similar to Example 1 revealed that this
fine organic silicone particle B had a hollow hemispherical body, was an
organic silicone fine particle having an average diameter of 0.9 μm in
a cross-section of the spherical surface, and was composed of a
polysiloxane cross-linked structure with a molar ratio of the siloxane
unit represented by Formula 1 to the siloxane unit represented by Formula
2 of 40/60.
[0339]With respect to the particle thus obtained, the average particle
distribution was adopted. Into the toner base particle A, 1.0% of this
hemispheric organic fine particles B was added and mixed using a HENSCHEL
oxide having an average particle diameter of 15 nm and 1.0 part of
a circumferential speed of stirring blades of 20 m/s to obtain toner B.
[0340]Following a procedure similar to Example 1, 400 g of an ion-exchange
water was poured into a reaction vessel, 0.34 g of a 48% aqueous solution
of sodium hydroxide and 0.17 g of a 20% aqueous solution of
α-(p-nonylphenyl)-ω-hydroxy (polyoxyethylene) (the number of
oxyethylene units=10) was added, and the resultant solution was stirred
this solution kept at 14° C., into this solution, a monomer
mixture of 32 g of methyl trimethoxy silane, 28.4 g of
was gradually delivered by drops so as not to mix the solution and the
monomer layer, after completion of the dropping, the solution and the
monomer layer were slowly stirred and hydrolyzed for three hours in a
laminar flow state maintaining both layers. Then the temperature of the
reaction system was raised to 30° C. to 80° C., the
resultant mixture was subjected to a condensation reaction for five hours
to obtain an aqueous suspension containing an organic silicone fine
particle. From this aqueous suspension, a white fine particle was
separated by a centrifugal machine. The white fine particle thus
separated was washed, and dried in a hot air at 150° C. for five
hours to obtain 60 g of fine organic silicone particle C.
[0341]The measurement and analysis similar to Example 1 revealed that this
fine organic silicone particle C had a hollow hemispherical body, was an
organic silicone particle having an average diameter of 0.6 μm in a
cross-section of the spherical surface, and was composed of a
[0342]With respect to the particle thus obtained, the average particle
hemispheric organic fine particle C was added and mixed using a HENSCHEL
diameter of 12 nm were added and mixed using a HENSCHEL MIXER at a
circumferential speed of stirring blades of 20 m/s to obtain toner C.
[0343]Into a reaction vessel, 400 g of an ion-exchange water was poured
and 0.35 g of a 48% aqueous solution of sodium hydroxide was added, and
an aqueous solution was thus obtained. Into this aqueous solution, 47 g
of methyl trimethoxy silane and 47.5 g of tetraethoxy silane were added
and subjected to a hydrolysis reaction for four hours keeping the
temperature at 13° C. to 15° C. to obtain a transparent
reactant containing a silanol compound. Then, this reactant was subjected
to a condensation reaction for five hours with the reactant temperature
kept at 30° C. to 80° C. to obtain an aqueous suspension
containing an organic silicone fine particle. This aqueous suspension was
filtered through a membrane filter, then, the filtrate was subjected to a
centrifugation to separate a white fine particle. The white fine particle
thus separated was washed and dried in a hot air at 150° C. for
five hours to obtain 55 g of fine organic silicone particle D.
[0344]The measurement and analysis similar to Example 1 revealed that this
fine organic silicone particle D had a hollow hemispherical body, was an
organic silicone fine particle having an average diameter of 6.0 μm in
[0345]With respect to the particle thus obtained, the average particle
hemispheric organic fine particle D was added and mixed using a HENSCHEL
circumferential speed of 20 m/s to obtain toner D.
[0346]Into the toner base particle A, 1.0% of non-cross-linked
monodispersion particle (MP-300 (a trade name) manufactured by Soken
Chemical & Engineering Co., Ltd.) having an average particle diameter of
0.1 μm was added and mixed using a HENSCHEL MIXER at a circumferential
speed of 20 m/s of stirring blades, and then, into this mixture, 0.8
parts of isobutyl-treated hydrophobic titanium oxide having an average
particle diameter of 15 nm and 1.0 part of hexamethyldisilazane-treated
hydrophobic silica having an average particle diameter of 12 nm were
added and mixed using a HENSCHEL MIXER at a circumferential speed of
stirring blades of 20 m/s to obtain toner E.
[0347]Into the toner base particle A, 1.0% of non-cross-linked
monodispersion particle (MP-10000 (a trade name) manufactured by Soken
0.4 μm were added and mixed using a HENSCHEL MIXER at a
circumferential speed of stirring blades of 20 m/s, and then, into this
mixture, 0.8 parts of isobutyl-treated hydrophobic titanium oxide having
an average particle diameter of 15 nm and 1.0 part of
a circumferential speed of stirring blades of 20 m/s to obtain toner F.
[0348]A silica sol obtained by a sol-gel method was subjected to an HMDS
treatment, and then dried and pulverized to obtain spherical
monodispersion silica having a volume average particle diameter D50 of
120 nm. This was called as monodispersion spherical silica A. Into the
toner base particle A, 1.0% of this monodispersion spherical silica was
stirring blades of 20 m/s, and then, into this mixture, 0.8 parts of
isobutyl-treated hydrophobic titanium oxide having an average particle
diameter of 15 nm and 1.0 part of hexamethyldisilazane-treated
stirring blades of 20 m/s to obtain toner G.
Image Forming Apparatus Used in Examples and Comparative Examples
[0349]The embodiment of the image forming apparatus used in Example and
the Comparative Examples will be described.
[0350]In the image forming apparatus, in the vicinity of or in contact
with a photoconductor drum which is an image bearing member, a charging
roller which evenly charges the photoconductor drum, an exposer which is
an exposing unit for forming a latent electrostatic image on the
photoconductor drum, a developing device which develops the latent
electrostatic image to form a visible image (toner image), a transfer
belt which transfers the toner image on a transfer paper, a cleaning
device which removes a residual toner remaining on the photoconductor
drum, a charge eliminating lamp which removes residual electricity on the
photoconductor drum, and a photo sensor which controls a voltage applied
to the charging roller and a toner concentration during developing are
disposed. The toner used in Examples or Comparative Examples is supplied
from a toner supplying device to the developing device through a toner
supply aperture. Image forming operation is performed as follows. The
photoconductor drum is rotated in an anticlockwise direction. On the
photoconductor drum, electricity is removed by electricity removing
light, and a surface potential is averaged to a standard potential of 0
to -150 V. Subsequently, the surface is charged by the charging roller to
make the surface potential around -1000 V. Then, the surface is exposed
by the exposer, and the surface potential on the image-formed portion
(Image portion) is irradiated with to become 0 to -200 V. The toner on
the sleeve adheres to the image portion by the developing device. The
photoconductor on which the toner image has been formed is rotated and
moved. A transfer paper is sent from a paper feeding section at the
moment a tip of the paper is aligned with a tip of the image on the
transfer belt, and the toner image on the photoconductor drum is
transferred onto the transfer paper by the transfer belt. Subsequently,
the transfer paper is sent to the fixing section, and the toner is
fusion-bonded by heat and pressure onto the transfer paper. Then the
paper is ejected as a copy. The residual toner remaining on the
photoconductor drum is scraped off by a cleaning blade in the cleaning
device. Subsequently, the residual electricity remaining on the
photoconductor drum is removed by the electricity removing light to place
the photoconductor drum in the initial state where no toner remains
thereon. The image forming apparatus starts the next image formation
[0351]Using the above image forming apparatus and the toners and the
developers of Examples and Comparative Examples, the following properties
(1) Toner Flowability Retainability
[0352]The toner flowability is evaluated as follows using POWDER TESTER
PT-S manufactured by Hosokawa Micron Corporation.
[0353]The toner immediately after its production is evaluated with
calculation using the POWDER TESTER PT-S manufactured by Hosokawa Micron
Corporation. The obtained value was represented as X.
[0354]Ten grams of the toner immediately after its production and 20 g of
an iron powder carrier having a volume average diameter of 50 μm which
had not been subjected to a surface treatment were mixed. The mixture was
placed in a 50 ml glass vial tube and encapsulated in the glass vial
tube. A forced vibration was applied to the glass vial tube at the
maximum vibration amplitude using ROCKING MILL manufactured by SEIWAGIKEN
[0355]After 30 minutes, the mixture was removed from the vial tube and
subjected to sieving to separate the toner from the iron powder carrier
using a sieve with openings of 25 μm. Then the deteriorated carrier
thus obtained was evaluated with calculation using PT-S. The obtained
value was represented as Y.
[0356]The flowability retainability is calculated from the following
Flowability retainability=(1-|(X-Y)/X|)
[0357]A value of 80 or more is classified as `A`, a value of 60 or more
and less than 80 is classified as `B`, and a value of less than 60 is
classified as `C`.
(2) Cleaning Ability
[0358]For evaluating the cleaning ability, in a test room at
temperature/humidity of 10° C./15% RH, using an image forming
apparatus manufactured by Ricoh Company, Ltd., 5,000 sheets of paper were
passed, subsequently the machine was stopped during passing a blank
image, a transfer residual toner remaining on the photoconductor passed
the cleaning step was transferred onto a blank paper via Scotch tape
(manufactured by Sumitomo 3M Ltd.), which was then measured by Macbeth
reflection densitometer RD514 type. The cleaning ability was evaluated
quantitatively as follows. A toner with a difference between the tape and
a blank being less than 0.01 and excellent cleaning ability was
classified as `A`. A toner of which the difference therebetween being
0.01 to 0.02 and the cleaning ability was not excellent but acceptable
was classified as `B`. A toner of which the difference therebetween being
more than 0.02 and the cleaning ability was poor was classified as `C`.
[0359]For the image quality, image quality degradation (specifically,
occurrence of transfer fault and image scumming) of the image after
passing paper sheets was comprehensively evaluated. Using an image
forming apparatus manufactured by Ricoh Company, Ltd., 5,000 sheets were
passed, subsequently a black solid image was passed, and for the
resulting image, transfer fault level was visually evaluated and ranked.
[0360]For the image scumming, using an image forming apparatus
manufactured by Ricoh Company, Ltd., 5,000 sheets were passed,
subsequently the machine was stopped during developing a blank paper
image, the developer on the photoconductor after the developing was
transferred onto a tape, and the difference in the image density between
the tape and a developer-untransferred tape was measured by a
spectrodensitometer (manufactured by X-Rite), and evaluated
quantitatively. A toner with the difference therebetween being less than
0.30 was classified as `A`, and a toner with the difference being 0.30 or
more was classified as `C`.
[0361]Comprehensively evaluating the transfer fault and the image scumming
occurrence, a toner exhibiting excellent image quality was classified as
`A`, a toner of which the image quality was not excellent but acceptable
was classified as `B`, and a toner of which the image quality was poor
was classified as `C`.
(4) Photoconductor Flaws
[0362]Occurrence of photoconductor flaws was evaluated in an image forming
apparatus manufactured by Ricoh Company, Ltd., through which 100,000
sheets of a 4% image density of A4 size image were printed. A toner with
which the photoconductor had no flaw or a minute flaw and was in a very
good condition was classified as `A`, a toner with which the
photoconductor had a few flaws, which was however not reflected in a
printed image, and thus was acceptable was classified as `B`, and a toner
with which the photoconductor had a few flaws, which was reflected in
printed images or with irretrievable flaws was classified as `C`.
[0363]The evaluation results are shown in Table 1.
flowability Photo-
retain- Filming of Cleanig Image conductor
ability photoconductor ability quality flaw
Example 1 B A A A A
Example 3 B A A A A
Comparative B C B A C
[0364]By mixing an organic silicone fine particle satisfying specific
conditions in a toner, it becomes possible to maintain excellent cleaning
ability and image quality in electrophotographic processes, and to
effectively prevent an occurrence of flaws on a photoconductor surface.
Patent applications by Ryota Inoue, Mishima-Shi JP
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