JPH08184981A - Image forming device - Google Patents

Abstract

PURPOSE: To obtain an image forming device by which a clear image is obtained by using an intermediate transfer body whose transfer efficiency is excellent and which is constituted so that filming is prevented from occurring by specifying relation between the solubility index of binding resin in a coating layer and the solubility index of additive in the coating layer. CONSTITUTION: The intermediate transfer body 20 is driven to be rotated at an identical circumferential speed to a photoreceptor drum 1. The transfer body 20 is constituted of a pipe-like core bar 100 being a supporting body and the coating layer 101 formed on the outside circumferential surface of the core bar 100. Then, the image forming device is provided with the transfer body 20 having the coating layer 101 and an image carrier 1 for transferring the image on the transfer body 20. Besides, the relation between the solubility index SP1 of the binding resin in the layer 101 and the solubility index SP2 of the additive in the layer 101 is defined as |SP1-SP2|<=4. Since the binding resin and the additive being in such relation are provided with high affinity, the additive does not flocculate in the binding resin and it uniformly exists extending over the whole layer nearly in a single grain state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus, and more particularly, to a second image after a toner image formed on a first image carrier is once transferred onto an intermediate transfer member.
And an image forming apparatus such as a copying machine, a printer or a fax machine, which is further transferred onto the image carrier to obtain an image formed product.

[0002]

2. Description of the Related Art An image forming apparatus using an intermediate transfer member is
A color image forming apparatus, a multicolor image forming apparatus, or a color image that outputs an image formed product in which a plurality of component color images of color image information or multicolor image information are sequentially laminated and transferred to synthesize and reproduce the color image or the multicolor image. It is effective as an image forming apparatus having a forming function and a multicolor image forming function, and it is possible to obtain an image with no misregistration (color misregistration) of each component color image.

A color electrophotographic apparatus having an image forming apparatus using the above-mentioned intermediate transfer member is a conventional technique, in which a second image carrier is attached or adsorbed on a transfer drum,
A color electrophotographic apparatus having an image forming apparatus for transferring an image onto the first image carrier, for example, JP-A-63-
It is superior to the transfer method as described in JP-A-301960 in the following points. That is, there is little color shift when the toner images of the respective colors are superposed. In addition, the second image carrier can be selected in various ways. For example,
Thin paper (40 g / m ² paper) to thick paper (200 g / m ²⁾
Paper) can be selected. Transfer is possible regardless of whether the second image carrier is wide or narrow. Furthermore, it is possible to handle envelopes, postcards, label paper, and the like.

In many cases, the intermediate transfer member is rarely used as a single layer, and it is common to use a coating layer having a multi-layered structure with separated functions. At this time, as a method for forming the coating layer, there are melt molding, injection molding, dip coating, spray coating and the like. Such a coating method has advantages that continuous production of the intermediate transfer member is possible, a mold that can be produced at a relatively low cost, and a large-sized molding apparatus are not required.

[0005]

However, on the other hand, uneven thickness of the coating layer in the coating process, poor dispersion of coating components, uneven electric resistance and surface roughness are likely to occur. Furthermore, uneven electric resistance, cracks and peeling of the coating due to uneven heating in the drying step of the coating layer are likely to occur.

When these defects occur, the transfer efficiency is reduced due to partial electric resistance unevenness, and the characters 110 shown in FIG.
As described above, the image having the hollow portion 110a, the coating layer floats when repeatedly used, and the portion is not energized, so that an image defect such as a ring-shaped or dot-shaped white image loss occurs.

Further, when the intermediate transfer member is repeatedly used, there is a case where so-called filming occurs in which toner that cannot be completely removed by the cleaner is deposited on the surface of the intermediate transfer member. When filming occurs, it becomes difficult for the toner to be transferred from the first image bearing member to the intermediate transfer member, and a speckled white image is formed.

Several proposals have hitherto been made for the material used for the intermediate transfer material (see, for example, Japanese Patent Laid-Open No.
No. 81786, JP-A-4-88385, JP-A-3-242667, JP-A-5-333725).

The present invention has been made in view of the above circumstances, and an object thereof is to provide an image forming apparatus which can obtain a clear image by using an intermediate transfer member which is excellent in transfer efficiency and does not cause filming. To do.

[0010]

The image forming apparatus of the present invention comprises an intermediate transfer member having a coating layer and an image carrier for transferring an image to the intermediate transfer member, and the The solubility index SP1 of the binder resin and the solubility index SP2 of the additive in the coating layer have a relationship of | SP1-SP2 | ≦ 4.

The example of the image forming apparatus of the present invention shown in FIG. 1 is an apparatus for forming a color image (a copying machine or a laser beam printer), and a roller 20 having a medium resistance is used as an intermediate transfer member.

Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) which is repeatedly used as a first image bearing member, and rotates in a clockwise direction indicated by an arrow at a predetermined peripheral speed (process speed). Driven.

In the course of rotation, the photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by a primary charger (corona discharger) 2, and then an image exposure means (not shown) (color separation / combination of color original image). The image exposure optical system, a scanning exposure system by a laser scanner which outputs a laser beam modulated in response to a time series electric digital pixel signal of image information, etc. An electrostatic latent image corresponding to the color component image (for example, magenta component image) is formed.

Then, the electrostatic latent image is transferred to the first developing device 41.
It is developed by the magenta toner M which is the first color by the (magenta developing device). At this time, the second to fourth developing devices 4
2, 43, and 44 (cyan, yellow, and black developing units) are in the operation-off state and do not act on the photosensitive drum 1, and the magenta toner image of the first color is the second to fourth images.
Of the developing devices 42 to 44.

The intermediate transfer member 20 is rotationally driven in the counterclockwise direction indicated by the arrow at the same peripheral speed as the photosensitive drum 1. The intermediate transfer body 20 is a pipe-shaped core metal 100 that is a support.
And a coating layer 101 formed on the outer peripheral surface thereof.

The above-mentioned first formed and carried on the photosensitive drum 1.
While the color magenta toner image passes through the nip portion between the photosensitive drum 1 and the intermediate transfer body 20, the outer peripheral surface of the intermediate transfer body 20 is formed by the electric field formed by the primary transfer bias applied to the intermediate transfer body 20. Are sequentially transferred to the intermediate transfer.

The surface of the photosensitive drum 1 after the transfer of the magenta toner image of the first color onto the intermediate transfer member 20 is cleaned by the cleaning device 14.

Hereinafter, similarly, a cyan toner image of the second color,
The yellow toner image of the third color and the black toner image of the fourth color are sequentially superimposed and transferred onto the intermediate transfer body 20, and a composite color toner image corresponding to the target color image is formed.

Reference numeral 25 denotes a transfer roller, which is arranged in contact with the lower surface of the intermediate transfer member 20 so as to be in parallel with the bearing.

First from the photosensitive drum 1 to the intermediate transfer body 20
The primary transfer bias for sequentially superposing and transferring the toner images of the fourth color is the bias power supply 61 with the polarity (+) opposite to that of the toner.
Applied from. The applied voltage is, for example, +2 kV to +5.
It is in the range of kV.

First from the photosensitive drum 1 to the intermediate transfer body 20
The transfer roller 25 and the intermediate transfer member cleaner 35 can be separated from the intermediate transfer member 20 in the process of sequentially transferring the fourth color toner image.

The transfer of the composite color toner image superposedly transferred onto the intermediate transfer member 20 to the transfer material 24 which is the second image carrier is carried out while the transfer roller 25 is in contact with the intermediate transfer member 20. A copying material 24 such as paper is fed from the paper cassette 9 to the contact nip between the intermediate transfer body 20 and the transfer roller 25 at a predetermined timing, and at the same time, a secondary transfer bias is applied from the bias power source 29 to the transfer roller 25. . The secondary transfer bias causes the synthetic color toner image to be transferred from the intermediate transfer member 20 to the transfer material 24 which is the second image carrier. The transfer material 24 that has received the toner image transfer is the fixing device 1.
Then, it is heated and fixed.

After the image transfer onto the transfer material 24 is completed, the transfer residual toner on the intermediate transfer body 20 is cleaned by contact with the intermediate transfer body cleaner 35.

The intermediate transfer member used in the present invention has at least a first coating layer 101 on the outer peripheral surface of a core metal 100 as a support, as shown in FIG. Or FIG. 3 or FIG.
As shown in FIG.
2, or the second coating layer 102 and the third coating layer 103
May be included. In some cases, the intermediate transfer may be composed of only the coating layer without using the support. At least one of the coating layers is an elastic layer formed by melt molding, injection molding, dip coating, spray coating, or the like of a binder resin containing an additive.

The binder resin used in the coating layer is preferably rubber, elastomer or resin. Examples of the elastomer or rubber include styrene-butadiene rubber, high styrene rubber, butadiene rubber, isoprene rubber and ethylene-propylene. Examples thereof include copolymers, nitrile butadiene rubber, chloroprene rubber, butyl rubber, silicon rubber, fluororubber, nitrile rubber, urethane rubber, acrylic rubber, epichlorohydrin rubber and norbornene rubber. Further, as resins, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-
Chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer Polymers (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), Styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.), styrene-α -Methyl chloroacrylate copolymer, styrene-acrylo Tolyl - (homopolymer or copolymer containing styrene or styrene substituents) a styrene resin such as acrylic ester copolymer, a vinyl chloride resin,
Styrene-vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, low molecular weight polyethylene, low molecular weight polypropylene,
Examples thereof include ionomer resins, polyurethane resins, silicone resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins and polyvinyl butyral resins.

As the additive contained in the coating layer, high-molecular polymer particles having an average particle diameter of 0.1 to 100 μm are preferable.
Examples of such high-molecular polymer particles include L-lysine particles (preferable particle size 5 to 50 μm), particles made of silicone rubber or silicon resin (preferable particle size 1 to 10 μm).
m), polyvinylidene fluoride or polytoterafluoroethylene homopolymer particles or copolymer particles (preferable particle size 0.1 to 1 μm), melamine-formaldehyde resin particles (preferable particle size 0.1 to 3 μm), asparagine Acid lauryl ester particles (preferable particle size 1 to 30 μm
m), polybenzoicidazole particles (preferred particle size 10
˜100 μm), polyacrylonitrile particles (preferred particle size 1-10 μm), nylon particles (preferred particle size 2-
20 μm) is preferred.

In addition to the above, as the polymer particles, for example, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, Styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer) , Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene- Ethyl methacrylate copolymer, styrene-methacrylic acid block Alcohol copolymer and styrene - phenyl methacrylate copolymer), styrene -α- chloromethyl acrylate copolymer, styrene - acrylonitrile -
Acrylic ester copolymers and other styrene resins (styrene or styrene-substituted homopolymers or copolymers), vinyl chloride resins, styrene-vinyl acetate copolymers, rosin-modified maleic acid resins, phenol resins, epoxies Resin, polyester resin, low molecular weight polyethylene,
Component resin particles such as low molecular weight polypropylene, ionomer resins, polyurethane resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins and polyvinyl butyral resins, acrylic homopolymers, acrylic copolymers can be used.

For the coating layers other than the elastic layer, for example, a resistance modifier, a release agent, a binder resin, a viscosity modifier, a colorant, etc. are selected at appropriate times, and these components are dispersed and suspended in a solvent to obtain a coating material for the coating layer. After that, it is formed by dip coating, spray coating, blade coating, roller coating curtain coating or the like.

In the present invention, the solubility index SP1 of the binder resin contained in the coating layer and the solubility index SP2 of the additive added to the coating layer have a relationship of | SP1-SP2 | ≤4. The binder resin and the additive in this relationship have a high affinity, the additive does not aggregate in the binder resin, and the additive can exist uniformly throughout the layer in a state close to a single particle. If this additive has conductivity and is intended for resistance control, when a DC bias is applied to the intermediate transfer member,
A uniform electric resistance can be obtained over the entire surface of the intermediate transfer member, and transfer efficiency can be improved.

When the additive has releasability, the additive is evenly distributed on the surface of the coating layer,
After all, high transfer efficiency can be obtained.

Further, in the present invention, the amount of the additive used can be reduced.

The relationship between the solubility index SP1 of the binder resin and the solubility index SP2 of the additive may be within the range of the above formula, and does not depend on the magnitude of SP1 and SP2.

The solubility index (SP value) is a characteristic value that serves as a measure of miscibility. When the molecular cohesive energy is E and the molecular volume is V, the solubility index δ is given by the following equation.

Δ = (E / V) ^1/2

The solubility index (SP value) is one of the indexes expressing the intermolecular force of a substance, and is the Journal App.
ly Polymer Science. , 19, 11
63 (1975), it is shown as the sum of each force (energy) of dispersive force, polar effect, and hydrogen bond.

The thickness of the coating layer serving as the elastic layer is 0.5 to 1
It is preferably 0 mm. The thickness of the coating layer other than the elastic layer is 3 mm or less, more preferably 2 mm or less, and particularly 20 μm to
It is preferably 1 mm.

As the conductive support, for example, a metal or alloy such as aluminum, iron, copper and stainless steel, a conductive resin in which carbon or metal particles are dispersed, or the like can be used. A belt shape is preferable.

The volume resistivity of the intermediate transfer member is 10 ¹ to 10 ¹³
Ω · cm is preferable, and particularly 10 ² to 10 ¹⁰
It is preferably Ω · cm. In order to control the resistance as described above, a resistance control agent such as an electron conductor or an ionic conductor can be added to the coating layer at appropriate times within a range not impairing the performance.

Examples of preferred electron conductors are conductive metal oxides, graphite, metals (copper, aluminum,
Nickel and silver) and conductive polymers (polyaniline,
And polypyrrole, polythiophene, polyacetylene, polypyridine, polyacene, polyazulene, polydiphenylbenzidine, polyvinylcarbazole and poly-3-alkylthiophene). Of these, metals, polyaniline, polypyrrole and polythiophene are particularly preferred. Examples of preferred ionic conductors include metal salts and ammonium salts. Examples of the metal salt include salts of group I or group II metals, and among these, salts of Li, Na and K having a relatively small cation radius are particularly preferable. Examples of anions constituting these metal salts include halogen ions (F, Cl, Br and I etc.), thiocyanate ion, perchlorate ion, trifluoromethanesulfonate ion and fluoroborate ion.
Of these, particularly preferable are thiocyanate ion, perchlorate ion, trifluoromethanesulfonate ion and fluoroborate ion. As ammonium salts, carboxylic acids (adipic acid, phthalic acid,
Azelaic acid and the like), phosphoric acid, boric acid, sulfonic acid (aryl sulfonic acid and the like), and ammonium salts of acids such as borofluoric acid. Among these ammonium salts, ammonium carboxylate, ammonium phosphate and ammonium borate are particularly preferable. The electron conductor and the ionic conductor may be mixed and used.

When these resistance control agents are added to the coating layer, it is preferable to add them in an amount of 1.0% by weight to 200% by weight based on the resin solid content in the coating material for the coating layer.

The image forming apparatus shown in FIG. 5 uses a belt-shaped intermediate transfer member 104 as an intermediate transfer member.

As the first image carrier used in the image forming apparatus of the present invention, a roller-shaped or belt-shaped photosensitive member can be used, and the roller-shaped photosensitive member has higher transfer efficiency and image superposition (registration). It is preferable in the present invention that the deviation of () can be suppressed to a minimum.
This is presumed to have a favorable effect because the rigid intermediate transfer member and the rigid photosensitive drum are in contact with each other.

As the photosensitive layer of the photosensitive member, an OPC (organic, photoconductive material-containing) photosensitive layer, especially one having a layer containing fluororesin particles as the outermost layer thereof, causes friction with the intermediate transfer member on the surface of the rigid roller. It has the advantages that it is reduced to obtain high durability, the transfer efficiency is improved, and partial transfer failure is prevented.

[0044]

The present invention will be described in detail below with reference to examples. In addition, "part" shown below means a "polymerization part."

[Example 1] Diameter 182 mm, length 320
A roller (1) having an elastic layer with a thickness of 1 mm was obtained by transfer-molding a rubber compound having the following composition using a metal mold on the surface of an aluminum cylindrical roller having a thickness of 5 mm and a thickness of 5 mm.

Rubber compounded NBR rubber 100 parts Zinc oxide 2 parts Conductive carbon black 10 parts Paraffin oil 30 parts Vulcanizing agent (sulfur) 2 parts Vulcanization accelerator (dibenzothiazyl disulfide, MBT
S) Part 3

Next, in order to obtain a coating layer as an upper layer, a coating material for coating layer was prepared based on the following formulation.

Coating material for coating layer Polyurethane (solubility index 10) 100 parts Conductive tin oxide 40 parts Dispersion aid (coupling agent) 2 parts Spherical silicone rubber particles having an average particle diameter of 2.3 μm 30 parts (Solubility index 7.5) ) Kimi Ren 100 parts

A coating layer having a thickness of about 50 to 200 μm was formed on the surface of the roller (1) by spray coating the above coating composition, followed by drying and curing at 100 ° C. for 60 minutes to obtain an intermediate transfer member.

This intermediate transfer was mounted on the full-color electrophotographic apparatus shown in FIG. 1, and a full-color image copying test was repeatedly performed using an OPC photosensitive drum having a photosensitive layer on an aluminum cylinder as a photosensitive member.

The image forming conditions of this embodiment are shown below.

Photoconductor: OPC photosensitive drum Surface potential: -700V Color developer (both four colors): Non-magnetic one-component toner Primary transfer voltage: + 900V Secondary transfer voltage: + 3400V Process speed: 120mm / s Development bias: -500V

As a result, the transfer efficiency from the photosensitive drum, which is the first image carrier, to the intermediate transfer member (hereinafter referred to as the primary transfer efficiency) is 95%, and the transfer efficiency from the intermediate transfer member to the second image carrier is 80 g. The transfer efficiency (hereinafter referred to as the secondary transfer efficiency) to the / m ² paper was 92%. In addition, the full-color copied image had characters and fine lines without voids, and the solid image had a uniform image quality. After the durability test of 10,000 sheets, the same image quality as that at the initial stage was obtained, and the secondary transfer efficiency was 89%, which was almost unchanged. When the surface of the intermediate transfer body after 10,000 sheets were observed under a microscope, there was no filming due to the toner.

Next, an entire halftone image having an image density of 0.8 was copied, and the uniformity of the image quality was observed, but the image was good with no partial density unevenness or a blank image.

Further, the intermediate transfer member used for 10,000 sheets was not developed with toner up to 30,000, and only the charging-discharging was repeated for idling to confirm the durability, but the surface of the intermediate transfer member was conspicuous. Scraping and peeling between the elastic layer and the coating layer did not occur at all.

[Example 2] Acrylic rubber (solubility index 9.6) 100 parts Conductive carbon black 8 parts Paraffin oil 20 parts Vulcanizing agent (sulfur) 2 parts Vulcanization accelerator (MBTS) 2 parts Average particle size 3.4 μm polymethylmethacrylate particles
30 parts (solubility index 9.2)

A coating material having the above composition was applied to the surface of a cylindrical aluminum roller similar to that used in Example 1 to form a coating layer to obtain an intermediate transfer member.

This intermediate transfer member was used, and the others were used in Example 1.
In the same manner as the above, a 20,000-sheet repeated copying durability test using only magenta was performed.

The transfer efficiencies were 89% for the primary transfer and 84% for the secondary transfer, which were lower than those in the case where a coating layer was further provided on the elastic layer, but were lower than those in Comparative Example 1 described later.
A significant effect was seen.

Regarding the image quality, a uniform halftone was obtained over the entire surface of the image, and there was no density unevenness or void.

After 20,000 sheets, toner fusion on the intermediate transfer member,
Almost no filming occurred. The image quality was the same as the initial one.

Example 3 100 parts of fluororubber (solubility index 7.3) was used as the binder resin of the coating composition of Example 1, and 35 parts of spherical polystyrene particles having an average particle size of 2.5 μm (solubility index) were used as additives. It was changed to 9.03) and the other tests were performed in the same manner as in Example 1. However, the primary transfer efficiency was 96% and the secondary transfer efficiency was 94%, which were considerably high, and the image quality was good with no voids. . Filming did not occur even after the durability test.

Example 4 The coating material for the coating layer used in Example 1 was applied on the surface of an endless polytetrafluoroethylene belt to obtain a belt-shaped intermediate transfer member. This belt was subjected to a durability test of 10,000 sheets using the full-color electrophotographic apparatus shown in FIG.

As a result, the same good results as in Example 1 were obtained.

[Comparative Example 1] A durability test was conducted in the same manner as in Example 1 except that an intermediate transfer member having no coating layer (having only an elastic layer) was used in Example 1, but about 3
From 000 sheets, filming gradually occurs on the surface of the intermediate transfer member, and after 10,000 sheets, it becomes fine streaks like rain on the image, and the adverse effect of filming occurs. It was impossible. Further, as for the image quality, in the initial stage, it was a negligible minute portion of the blank image, but after 10,000 sheets, the image quality was clearly defective in the center of the character. The initial transfer efficiency is 91% for the primary transfer efficiency and 7 for the secondary transfer efficiency.
It was 6%.

Comparative Example 2 In Example 3, spherical nylon particles were replaced with 66 nylon particles 45 having an average particle size of 5 μm.
Other parts were tested in the same manner as in Example 3 except that the solubility index was changed to 13.6 (solubility index 13.6).
The secondary transfer efficiency was as low as 68%.

Further, during the durability test by repeated copying, nylon particles as an additive were gradually dropped from the coating layer, and filming due to adhesion of toner to the intermediate transfer member occurred after about 10,000 sheets. White spots due to improper transfer and hollow spots in the character area began to stand out. When observing the filming part with a microscope, it was confirmed that the toner particles were embedded in the traces from which the nylon particles had fallen off, which triggered this.
It is presumed that toner adhesion was promoted. This intermediate transfer member had poor durability as described above and was practically impossible.

[0068]

As described above, according to the image forming apparatus of the present invention, the transfer efficiency from the first image carrier to the intermediate transfer member and from the intermediate transfer member to the second image carrier is high. It is possible to obtain a uniform image without image defects such as hollow image, regardless of the type of paper or OHP sheet. Good characteristics are maintained even after endurance. Further, filming due to toner adhesion to the intermediate transfer body does not occur.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of an electrophotographic apparatus of the present invention.

FIG. 2 is a schematic sectional view of an example of an intermediate transfer member used in the present invention.

FIG. 3 is a schematic cross-sectional view of an example of an intermediate transfer member used in the present invention.

FIG. 4 is a schematic cross-sectional view of an example of an intermediate transfer member used in the present invention.

FIG. 5 is a schematic sectional view showing another example of the electrophotographic apparatus of the present invention.

FIG. 6 is a diagram showing an example of a hollow image.

[Explanation of symbols]

 1 Photosensitive Drum 20 Intermediate Transfer Body 100 Supports 101, 102, 103 Coating Layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akihiko Nakazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tsunenori Ashina 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. An intermediate transfer member having a coating layer, and an image carrier for transferring an image to the intermediate transfer member, the solubility index SP1 of a binder resin in the coating layer, and the coating layer. Solubility index of additives in SP2 is | SP1-SP2
An image forming apparatus having a relationship of | ≦ 4. 2. The image forming apparatus according to claim 1, wherein both the intermediate transfer member and the image bearing image member have a roller shape. 3. The image forming apparatus according to claim 1, wherein the intermediate transfer member has a belt shape, and the image carrier has a roller shape. 4. The image forming apparatus according to claim 1, wherein the image bearing member is an electrophotographic photosensitive member having an outermost layer containing fluororesin particles.