JP2003270961A - Intermediate transfer device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate transfer body with improved surface characteristics represented by wear resistance, release properties or the like in an image forming apparatus which uses an intermediate transfer device, moreover, to provide an intermediate transfer device free from side effects such as an abnormal image or the like during transfer, and to provide an image forming apparatus with high picture quality by using the above intermediate transfer device. <P>SOLUTION: In the intermediate transfer device, a plurality of visible color developed images successively formed on an image carrying body with toners are successively superposed on the intermediate transfer body which travels endless so as to subject the images to primary transfer, and then the primarily transferred images on the intermediate transfer body are collectively subjected to secondary transfer. In the device, at least the surface of the intermediate transfer body 23 is constituted from a material containing a polyimide-modified silicone resin. <P>COPYRIGHT: (C)2003,JPO

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 such as a copying machine, a printer, and a facsimile, and more specifically, an intermediate transfer member such as an intermediate transfer drum and a belt is used to interpose a primary transfer member. The present invention relates to an image forming apparatus using an intermediate transfer method involving a secondary transfer process.

[0002]

2. Description of the Related Art In recent years, electrophotographic image forming apparatuses capable of copying and printing full-color images have been put into practical use.
Intermediate transfer member Double transfer system (Yellow (Y), magenta (M), cyan (C), and black (Bk) color images formed for each color on an image carrier such as a photoconductor are transferred onto the intermediate transfer member. The method in which the transferred full-color toner images are collectively transferred to the transfer material (also referred to as an intermediate transfer method)) is advantageous in that it is paper-free and can copy the entire surface. .

In such an intermediate transfer type image forming apparatus, various parts are in contact with the surface of the intermediate transfer body. They are, for example, so-called secondary transfer rollers that are opposed to and abut against the intermediate transfer member when (secondarily) transferring the toner to the transfer material, in addition to the above-described photoconductor, toner, transfer material, and the like. A cleaning member such as a blade, a roller, or a brush for cleaning the toner remaining on the intermediate transfer body after the secondary transfer. Therefore, various mechanical and electrical external forces are constantly applied to the intermediate transfer member due to the rubbing action and the electrical action with these parts, and durability against these external forces is required.

In particular, various surface characteristics represented by abrasion resistance of the surface, releasability from toner and the like, and low coefficient of friction for reducing frictional force with each part are most important, and are improved. In order to achieve this, some materials used for the intermediate transfer member have been studied.

For example, there is an example in which a fluorine-based resin or elastomer is used for the surface layer of an intermediate transfer member (Japanese Patent Laid-Open No. 5-4041).
No. 7, JP-A-6-234903, JP-A-7-
92825, JP-A-8-267605, JP-A-10-166508). Fluororesin is known as a material having excellent releasability, but when it is used as a surface layer material, on the contrary, it has a defect such as poor adhesion to a base material and peeling, and the mechanical properties of the film are particularly Since it was not excellent, it had problems such as surface abrasion and scratch resistance.

Other high release materials include silicone resins and elastomers (Japanese Patent Laid-Open No. 5-46035).
JP-A-8-30117 and JP-A-9-269676.
JP-A-10-20538, JP-A-11-
231678, etc.) and polyolefin-based materials (Japanese Patent Laid-Open Nos. 5-311016 and 7-24912, etc.) and the like, but they also have similar drawbacks.

On the contrary, as a material having excellent mechanical properties, polycarbonate (Japanese Patent Application Laid-Open No. 6-93175, Japanese Patent Application Laid-Open No. 6-149081, Japanese Patent Application Laid-Open No. 6-149083, Japanese Patent Application Laid-Open No. 10-10880, Japanese Patent Application Laid-Open No. 10-10880) is used. 13-31
849, etc.) and polyimide (JP-A-7-15628).
7, JP-A-8-176319, JP-A-11
No. 24427, Japanese Patent Application Laid-Open No. 11-170389, Japanese Patent Application Laid-Open No. 12-172085, etc.), but these materials, on the contrary, do not have sufficient releasability, and toner particles and their additives on the surface. However, there was a problem in that

In addition to the above, polyester-based materials (JP-A-13-13801, JP-A-13-18284, etc.) and polyurethane-based materials (JP-A-10-31972)
No. 7, Japanese Patent Laid-Open No. 11-30915, etc.), but none of them satisfy both the wear resistance and the releasability at the same time.

Further, there are problems such as image quality related to the intermediate transfer device using the intermediate transfer member. These are for example
In the step of transferring the toner image from the photoconductor to the intermediate transfer body (primary transfer) and the step of transferring the intermediate transfer body to a transfer material such as paper (secondary transfer), the transfer rate of the toner is increased as much as possible,
In addition to the need to reduce residual toner as much as possible, it is also important to reduce abnormal images as much as possible.

The present invention is intended to improve and improve the transfer rate, and in particular, to improve an abnormal image relating to a system using an intermediate transfer member, so-called "toner scattering during transfer" (hereinafter, transfer dust).

Here, the transfer dust means that the visible image formed on the image carrier at the time of primary transfer is not transferred to a position where it should be transferred but is diffused and transferred to the peripheral portion thereof.
As a result, this is a phenomenon in which the image is blurred, and the sharpness of the image is impaired particularly in the thin line portion.

A typical conventional technique for improving image quality in the above-mentioned intermediate transfer system is Japanese Patent Laid-Open No. 63-34570.
Japanese Patent Application Laid-Open No. 63-3457, in which high-resistance toner is non-electrostatically transferred onto an intermediate transfer medium, and then is press-transfer fixed by a heating roll with a recording sheet interposed.
As disclosed in Japanese Patent Laid-Open No. 1-2825, a conductive toner is non-electrostatically transferred to an intermediate transfer medium, and then a recording sheet is interposed between the conductive toner and a transfer roll for pressure transfer fixing.
Japanese Patent Application Laid-Open No. 2-183276, as described in Japanese Patent Application Laid-Open No. 71-183276, the toner image transferred by a paper peeling charger is removed every time the toner image is transferred to an intermediate transfer medium.
As disclosed in Japanese Patent Laid-Open No. 4 (1999) -163, the transfer potential at the final transfer stage is made higher than the transfer potential immediately before, and a predetermined voltage is applied to the intermediate transfer medium during the transfer to each transfer stage.
As described in Japanese Patent Publication No. 147170, there may be mentioned a means for removing charges on the intermediate transfer body before the means for transferring the visible image from the intermediate transfer body to the sheet.

However, among these conventional techniques,
JP-A-63-34570 and JP-A-63-3457.
According to Japanese Patent Laid-Open No. 1, a recording sheet that can be pressed, transferred and fixed by a heating roll is required, and the paper-free property, which is an advantage of the intermediate transfer member transfer system, cannot be utilized.
In addition, JP-A-1-282571 and JP-A-2-18
In Japanese Patent No. 3276 and Japanese Patent Laid-Open No. 4-147170,
In either case, it becomes necessary to provide a means for removing electricity or applying a voltage and / or this control means, which not only complicates the machine control mechanism, but also hinders downsizing of the machine.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned conventional techniques, and more specifically, an intermediate transfer member having improved surface characteristics represented by abrasion resistance and releasability. It is another object of the present invention to provide an intermediate transfer device which does not cause side effects such as other abnormal images at this time.

Still another object of the present invention is to provide an image forming apparatus of high image quality using the intermediate transfer device of the present invention.

[0016]

In order to solve the above-mentioned problems, in the invention described in claim 1, a plurality of visible color developed images sequentially formed on the image carrier by toner are run endlessly. Primary transfer is performed by sequentially superimposing on the intermediate transfer body,
An intermediate transfer device for collectively secondary-transferring a primary transfer image on the intermediate transfer member onto a transfer material, wherein at least the surface of the intermediate transfer member is made of a material containing a polyimide-modified silicone resin. Is the most important feature.

The invention according to claim 2 is characterized mainly in the intermediate transfer device according to claim 1, wherein the silicone component in the polyimide-modified silicone resin is composed of a dimethylsiloxane monomer component.

The third aspect of the present invention is characterized mainly in the intermediate transfer device according to the first aspect, in which the silicone component in the polyimide-modified silicone resin is crosslinked with a silicone crosslinking agent.

According to the invention of claim 4, the volume resistance of the layer made of a material containing a polyimide-modified silicone resin is in the range of 10 ⁸ Ω · cm or more and 10 ¹² Ω · cm or less. The device is the main feature.

A fifth aspect of the present invention is characterized mainly in the intermediate transfer device according to the fourth aspect, in which conductive tin oxide is added to a layer made of a material containing a polyimide-modified silicone resin.

The invention according to claim 6 is characterized mainly in the intermediate transfer device according to claim 5, wherein the conductive tin oxide is surface-treated with a silane coupling agent.

According to a seventh aspect of the present invention, the intermediate transfer member is composed of a plurality of layers, and the surface layer made of a material containing at least a polyimide-modified silicone resin and the underlying layer have a volume resistance of 10 ¹² Ω · cm or less. An intermediate transfer device according to claim 1, which has a rubber base material having an effective hardness of JIS A 95 degrees or less.

The invention of claim 8 is characterized in that an intermediate transfer device according to claim 7 is characterized in that the rubber base material is a mixture of either one or both of nitrile-butadiene rubber and shrimp chlorohydrin rubber. To do.

According to a ninth aspect of the invention, there is provided an image forming layer apparatus comprising at least charging, exposing, developing, intermediate transferring, cleaning and neutralizing devices and an electrophotographic photosensitive member, and any one of the first to eighth aspects. An image forming apparatus using the intermediate transfer device described in item 1 is the most main feature.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An intermediate transfer device of the present invention will be described with reference to the drawings. FIG. 1 shows an example in which a drum is used as an intermediate transfer member as a typical example of the intermediate transfer device of the present invention. The outline of the primary transfer and the secondary transfer will be described based on this example.

First, the primary transfer will be described. Toner 27 developed on the photoconductor 18 by a developing device (not shown)
Is brought into contact with the intermediate transfer drum 11 that rotates in synchronization with the photoconductor 18 at the primary transfer portion, is given a predetermined bias potential, and is transferred to the intermediate transfer drum 11. Each color (black, yellow,
The toner developed in magenta and cyan is the photosensitive member 18
The toner image is transferred from above to the intermediate transfer drum 11, and the toner image is superimposed on the intermediate transfer drum 11.

Next, the secondary transfer will be described. The secondary transfer roller 23 is usually separated from the intermediate transfer drum 11, but is closely attached to the intermediate transfer drum 11 during the secondary transfer. The transfer material 26 is conveyed in synchronization with the intermediate transfer drum 11 and passes through the gap between the intermediate transfer drum 11 and the secondary transfer roller 23. At this time, a bias voltage having a polarity opposite to the charging polarity of the toner is applied to the secondary transfer roller 23, and the toner 27
Is secondarily transferred to the transfer material 26. After that, the transfer material 26 is given a predetermined charge by the sheet charge eliminator 28, the accumulated charge is removed, and the transfer material 26 is easily separated from the intermediate transfer drum 11. After that, the transfer material 26 moves to a fixing process (not shown). Further, the toner 27 remaining on the intermediate transfer drum 11 is removed by a predetermined cleaning unit 25 (for example, a brush, a roller, etc.) contacting the intermediate transfer drum 11,
Will be initialized.

The intermediate transfer drum 11 is formed by coating a cylindrical aluminum tube with various materials in order to improve surface characteristics. The present invention is characterized in that at least the surface of this intermediate transfer member is made of a material containing a polyimide-modified silicone resin.

Next, the polyimide-modified silicone resin used in the present invention will be described. The polyimide-modified silicone resin used on at least the surface of the present invention can be represented by the following general formula.

[Chemical 1] (In the formula, X is a tetravalent aromatic ring or an aliphatic ring group,
R₁, R₆Is a divalent organic group, R ₂~ R_FiveIs an alkenyl group,
An alkyl group, a phenyl group, or a substituted phenyl group, n
Represents an integer of 5 or more)

Polyimide is generally known as a high-strength and rigid resin, but the introduction of a siloxane structure in the main chain provides flexibility and further has the advantage of improving releasability. Therefore, it becomes possible to satisfy the wear resistance and the toner releasability of the intermediate transfer member by including at least the surface of the above material.

In the structure of the polyimide-modified silicone resin,
R _{2 to} R ₅ are preferably C _{1 to} C ₃ alkyl groups, particularly methyl groups. The side chain of the siloxane structure makes it possible to reduce the surface characteristics, especially the friction coefficient. In the case of the intermediate transfer member, since there are many contact members as described above, the friction coefficient must be reduced in order to reduce the driving torque. Is preferably in the range of 0.2 to 0.4. In a polyimide-modified silicone resin, this can be achieved by using a dimethylsiloxane monomer component in which a methyl group is introduced into R _{2 to} R ₅ as a siloxane unit.

Such a polyimide-modified silicone resin
Is siloxane diamine, aromatic diamine, tetracal
Producing a mixture consisting of boric acid dianhydride as a raw material
be able to. As the siloxane diamine compound, H₂N-R₁-(-SiR₂R₃-O-) n-SiR_FourR_Five−
R₆-NH₂ (R₁, R₆Is a divalent organic group, R₂~ R_FiveIs an alkyl group,
A phenyl group or a substituted phenyl group, n is 5 to 50
Is shown as a general formula, and specifically, bis
(3-aminopropyl) tetramethyldisiloxane, bi
Sus (10-aminodecamethylene) tetramethyldisiroki
Sun, dimethylsiloxa with aminopropyl end groups
Tetramer, octamer, bis (3-aminophenoxymethyi
Ru) tetramethyldisiloxane and the like.

Aromatic diamines used in the polyimide-modified silicone resin of the present invention include, for example, (1) biphenyl diamine compounds, diphenyl ether diamine compounds, benzophenone diamine compounds, diphenyl sulfone diamine compounds, diphenylmethane diamine compounds, 2 , 2-bis (phenyl) propane and other diphenylalkane-based diamine compounds, 2,2-bis (phenyl) hexafluoropropane-based diamine compounds, diphenylene sulfone-based diamine compounds, (2) di (phenoxy) benzene-based diamine compounds , Di (phenyl) benzene-based diamine compounds, (3) di (phenoxyphenyl) hexafluoropropane-based diamine compounds, bis (phenoxyphenyl) propane-based diamine compounds, etc. Benzene ring, etc.) two or more, in particular aromatic diamine compounds having 2 to 5 "primarily can be mentioned aromatic diamine containing them alone or can be used as a mixture.

As the aromatic diamine, especially 1,
Diphenyl ether-based diamine compounds such as 4-diaminodiphenyl ether and 1,3-diaminodiphenyl ether, di (phenoxy) benzene such as 1,3-di (4-aminophenoxy) benzene and 1,4-bis (4-aminophenoxy) benzene Diamine compounds, 2,
2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy)
Examples thereof include bis (phenoxyphenyl) propane-based diamine-based compounds such as phenyl] propane.

Next, the tetracarboxylic dianhydride used in the present invention will be specifically described. As tetracarboxylic dianhydride, pyromellitic dianhydride and 3,3 ', 4,4'-diphenylsulfone tetracarboxylic acid are used. Dianhydride, 3,
3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 2,3 ', 3,4'-biphenyltetracarboxylic dianhydride , Bis (3,4-dicarboxyphenyl) ether dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, ethylene glycol bistrimellitate dianhydride, 2,2
-Bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride and the like.

The polyimide-modified silicone resin used in the present invention can be produced by a known method using the compounds listed above. For example, a method for directly obtaining a polyimide by heating these in an organic solvent in the presence of a catalyst such as tributylamine, triethylamine, or triphenyl phosphite as necessary, reacting a tetracarboxylic dianhydride and a diamine in an organic solvent. After obtaining a polyamic acid that is a precursor of polyimide, a dehydration catalyst such as p-toluenesulfonic acid is added if necessary, and imidization is performed by heating to obtain a polyimide, or this polyamic acid is converted into acetic anhydride. , Acid anhydrides such as propionic anhydride and benzoic anhydride, dehydration ring-closing agents such as carbodiimide compounds such as dicyclohexylcarbodiimide and a method of chemically ring-closing by adding ring-closing catalysts such as pyridine, isoquinoline, imidazole and triethylamine as necessary. There is.

The polyimide-modified silicone resin of the present invention can be used by appropriately adding a crosslinking agent capable of crosslinking a silicone polymer. The cross-linking agent is not particularly limited and conventionally known ones can be used. For example, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, dicumyl peroxide, t
Examples include peroxide-based crosslinking agents such as -butylcumyl peroxide and 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane. These may be used alone or in combination of two or more. Among them, benzoyl peroxide is preferably used from the viewpoint of crosslinkability.

The amount of the crosslinking agent added is preferably 0.5 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the polyimide-modified silicone resin. If the amount added is less than 0.5 parts by weight, the crosslinking property will not be sufficient, and if it exceeds 10 parts by weight, the excess crosslinking agent will adversely affect the releasability of the intermediate transfer member.

The intermediate transfer member of the present invention contains a polyimide-modified silicone resin on at least the surface thereof, and the volume resistance of the layer containing the polyimide-modified silicone resin is 10 ⁸
It is in the range of Ω · cm or more and 10 ¹² Ω · cm or less. The toner transfer rate can be improved by controlling the volume resistance within the range of the present invention. If the transfer rate is low, there are problems that the burden on the cleaning of the photoconductor or the intermediate transfer body is increased, and the loss of toner is increased. The toner transfer rate required for the intermediate transfer device is 90% or more in both primary and secondary transfer.

As the resistance control agent used in the intermediate transfer member of the present invention, a general and ordinary resistance control agent can be used. Specifically, carbon black such as Ketjen black and acetylene black, fine metal powder such as Ni powder, metal oxide such as tin oxide, titanium oxide and zinc oxide, and heteroatom (for example, antimony) -doped metal oxide. Materials, organic compounds or polymers containing quaternary ammonium base, carboxylic acid group, sulfonic acid group, sulfuric acid ester group, phosphoric acid ester group, etc., ether ester amide or ether amide imide polymer, ethylene oxide-epihalohydrin copolymer An organic antistatic agent such as an organic antistatic agent such as a polymer, a compound having a conductive unit typified by methoxypolyethylene glycol acrylate, or a polymer compound can be used.

However, 10 ⁸ Ω · cm or more 10 ¹² Ω · c
Tin oxide is preferable because it can stably control the volume resistance in the range of m or less and is excellent in environmental stability, and most preferable is one doped with a different atom such as antimony because it is excellent in conductivity. This is, for example, spherical particles (T-1; Mitsubishi Materials Corp.) and scale particles (ELCOM-TL-2).
0; Catalyst Chemical Industry Co., Ltd., and any of them can be used.

Further, the present inventors have found that surface treatment of the tin oxide particles with a silane coupling agent can improve image dust during transfer. The silane coupling agent that can be used for the surface treatment of the tin oxide of the present invention,
Conventional commercially available products can be used. For example SH60
20 (γ- (2-aminoethyl) aminopropyltrimethoxysilane), SZ6023 (γ- (2-aminoethyl) aminopropylmethyldimethoxysilane), SH6
026 (aminosilane), SZ6032 (N-β- (N
-Vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane / hydrochloride), SZ6050 (aminosilane), SZ6083 (γ-anilinopropyltrimethoxysilane), AY43-021 (octadecyldimethyl [3- (trimethoxysilyl)) Propyl] ammonium chloride), AY43-031 (γ-ureidopropyltriethoxysilane), SZ6030 (γ-methacryloxypropyltrimethoxysilane), SH604.
0 (γ-glycidoxypropyltrimethoxysilane), etc. (all are Toray Dow Corning Silicone Co., Ltd.)
Manufactured).

The surface treatment of tin oxide with a silane coupling agent can be carried out, for example, as follows. 1 part by weight of a silane coupling agent is added to 100 parts by weight of tin oxide, and the mixture is stirred with a high-speed mixer for 5 to 10 minutes to adhere the silane coupling agent to the surface of tin oxide. Next, it is taken out from the high speed mixer and dried at 100 to 150 ° C. for 1 hour. This surface-treated product can be handled in the same manner as an untreated product when the intermediate transfer member of the present invention is manufactured (described later).

The intermediate transfer member of the present invention is characterized in that at least the surface is made of a material containing a polyimide-modified silicone resin, but a layer containing a polyimide-modified silicone resin is provided on a conductive rubber layer. Is preferred. This imparts flexibility to the intermediate transfer member, especially O
By ensuring stable contact with a hard transfer material such as HP, it is possible to prevent the phenomenon such as toner dropout.

As a material used for the rubber layer, a general material can be used. Specifically, polyurethane, butyl rubber, nitrile butadiene rubber, epichlorohydrin rubber, polyisoprene rubber, polybutadiene rubber, silicone rubber, fluorine rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, chloroprene rubber, acrylic. Rubber,
And mixtures thereof and the like can be used. These rubber materials are usually insulative except for a part thereof, but since they can improve the toner transfer rate, it is possible to add a resistance control agent to make them conductive and use them. In that case, the volume resistance of the rubber layer is preferably 10 ¹² Ω · cm or less, and further 10
Most preferred is ⁸ Ω · cm or more and 10 ¹² Ω · cm or less. The effective hardness of the rubber layer is preferably JIS A 95 degrees or less. The effective hardness is defined as a value obtained by directly measuring the hardness of the intermediate transfer member with a hardness meter, and when the effective hardness exceeds JISA 95 degrees, sufficient flexibility is not exhibited and a toner dropout phenomenon occurs. Nitrile butadiene rubber and epichlorohydrin rubber are particularly preferable because the resistance of the material itself is low and the conductivity can be stably ensured without using a resistance control agent. Either one of these may be used, or both may be mixed and used.

In the layer containing at least the polyimide-modified silicone resin of the present invention, various organic / inorganic materials may be mixed and used, if necessary, in addition to the resistance control agent. Other organic resin materials that can be mixed include alkyd resins, chlorinated polyethers, chlorinated polyethylenes, epoxy resins, fluororesins, phenolic resins, polyamides,
Examples thereof include polycarbonate, polyethylene, methacrylic resin, polypropylene, polystyrene resin, polyurethane, polyvinyl chloride, polyvinylidene chloride, and silicone resin. These may be dissolved in a solvent and used, or one of them may be mixed in the form of resin fine particles.

Next, the form of the intermediate transfer member of the present invention will be described. Although the intermediate transfer drum has been used in the above description, the present invention is not limited to this, and any form can be used, but as a form other than the drum form, a belt form is preferably used. Is mentioned.
A typical example thereof is shown in FIG. According to this aspect, since the intermediate transfer member has the shape of the belt 11, there is an advantage that the degree of freedom in layout is large and the apparatus can be downsized. In the case of a belt shape, the layer containing at least the polyimide-modified silicone resin of the present invention may be used alone, or the layer containing at least the polyimide-modified silicone resin of the present invention may be provided on the surface of the belt base material composed of rubber or resin. It doesn't matter. Regarding other symbols,
The description is omitted because it is the same as in FIG. 1.

Next, the method for producing the intermediate transfer member of the present invention will be described. First, a method of dissolving a polyimide-modified silicone resin in a solvent and performing coating molding will be described. When the intermediate transfer member is prepared by dissolving the polyimide-modified silicone resin in a solvent, it can be carried out according to a conventional method. For example, a liquid composition prepared by dissolving or dispersing each of the above-mentioned components in a solvent is used as a suitable carrier (support). It can be carried out by casting on the body) and then removing the solvent by drying.

There is no particular limitation on the carrier, and those used in a general solution casting method are used. For example, a metal such as SUS or Al, a conductive resin, a rubber roller or belt, or the like can be used. Can be mentioned. Examples of the solvent include N-methyl-2-pyrrolidone, N, N-
Dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, hexamethylphosphoric triamide, 1,3-dimethyl-2-imidazolidone, hexane, benzene, toluene, xylene, methyl ethyl ketone, acetone, diethyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxymethane, diethylene glycol dimethyl ether, methyl cellosolve, cellosolve acetate, methanol, ethanol, propanol, isopropanol, methyl acetate,
Ethyl acetate, acetonitrile, methylene chloride, chloroform, carbon tetrachloride, chlorobenzene, dichlorobenzene, dichloroethane, trichloroethane and the like,
From these, the type and amount are appropriately selected and used so that each component is dissolved and dispersed. The concentration of the polyimide-modified silicone resin in the solvent is appropriately selected according to the film thickness to be produced, but is usually 0.1 to 60% by weight, preferably 1 to 5%.
It is in the range of 0% by weight, more preferably 5 to 45% by weight. When the concentration of the cyclic olefin-based polymer is in this range, the film thickness can be easily adjusted and the film forming property is excellent, which is preferable.

The method of casting the liquid composition on a carrier is not particularly limited, but for example, a doctor knife, a meer bar, a roll coat or the like can be used. The liquid composition can be cast by spraying, brushing, rolling, spin coating, dipping or the like. When the desired film thickness cannot be obtained by one application, the application can be repeated.

Next, the method of molding the belt will be described. Centrifugal molding is a typical method for producing a belt substrate using the polyimide-modified silicone resin of the present invention. This is because a raw material solution (hereinafter also referred to as a coating solution) as a belt material is poured from a spray or a nozzle into a rotating cylindrical molding die of a resin solution dissolved in a solvent, and the molding die is rotated at a high speed. While a method of forming an endless belt by spreading the coating solution by the centrifugal force to solidify this film as a uniform film (so-called centrifugal molding method), according to this method, Since the applied coating solution is spread by centrifugal force, it is easy to obtain a coating layer having a relatively uniform thickness.

In the production of the belt by the centrifugal molding, after applying the fluid coating solution on the inner surface of the cylindrical mold, the coating solution is rotated by a high speed centrifugal force so as to make the film thickness uniform. The force to overcome the surface energy spreads the coating film to make the film uniform. Then, the coating solution is prepared by diluting the raw material varnish with a solvent and is applied to the molding die. Therefore, the coating liquid is uniformly applied to the inner surface of the mold during high-speed rotation, but gradually accumulates at the bottom of the mold when the rotation is stopped or the rotation speed is slowed.
Therefore, according to this centrifugal molding method, it is necessary to remove the solvent and solidify it while maintaining a constant uniform solution film state.

Next, an example of an image forming apparatus using the intermediate transfer member of the present invention will be specifically described with reference to FIGS. FIG. 3 shows an example of a full-color electrophotographic apparatus using an intermediate transfer drum as an intermediate transfer body. Charger 20
The latent image formed on the photoconductor 18 by being charged by the exposure unit 21 and exposed by the exposure unit 21 is first visualized by the developing unit 19a of the developing unit 19 for the first color, and then contacted with the intermediate transfer drum 11. It is transferred to the intermediate transfer drum 11 at the contact portion. The transfer here is called primary transfer. On the other hand, after the visible image is primarily transferred to the intermediate transfer drum 11, the photoconductor 18 is neutralized by the pre-cleaning static eliminator 24, and the cleaning unit 2
The residual charge is removed by being cleaned in step 5 and entirely exposed by the charge-removing lamp 26, and the second color image forming step is performed. 19b for full color
By the developing unit of 19 to 19d, three or four colors are repeated to form a full-color image on the intermediate transfer body, that is, the intermediate transfer drum 11. The image formed on the intermediate transfer drum 11 is
Next, they are collectively transferred onto a transfer material 15 such as paper. The transfer here is called secondary transfer. Here, a transfer bias voltage is applied by the transfer roller 13, and then the transfer material 15 is output as a full-color image through a fixing process.

FIG. 4 shows an example of a full-color electrophotographic apparatus using an intermediate transfer belt as an intermediate transfer member. The latent image formed on the photoconductor 18 by being charged by the charger 20 and exposed by the exposure unit 21 is first visualized by the first-color developing unit 19a of the developing unit 19, and then the intermediate transfer belt 11 is formed. It is transferred to the intermediate transfer member at the contact portion with. The transfer here is called primary transfer. On the other hand, after the visible image is primarily transferred to the intermediate transfer belt 11, the photoconductor 18 is neutralized by the pre-cleaning static eliminator 24, and the cleaning unit 2
The residual charge is removed by cleaning the entire surface with the discharging lamp 26 and exposing the entire surface with the discharging lamp 26, and the resultant is subjected to the second color image forming process. In the case of full color, this step is 19b ~
Repeat 3 or 4 colors with 19d developing unit,
A full-color image is formed on the intermediate transfer body, that is, the intermediate transfer belt 11. The images formed on the intermediate transfer belt 11 are then collectively transferred onto a transfer material 15 such as paper. The transfer here is called secondary transfer. Here, a transfer bias voltage is applied by the transfer roller 13, and then the transfer material undergoes a fixing process and is output as a full-color image. The endless intermediate transfer belt 11 includes a backup roller 12, a bias roller A, a ground roller B, a tension roller C, and a drive roller D.
It is bridged between each roller such as, and rotates in the direction of the arrow in the figure. In the figure, 22 is a potential sensor and 23 is a P sensor.

[0055]

The present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following examples.

Examples 1 and 2 and Comparative Examples 1 to 3 A wear test was conducted by the following method. An aluminum sheet (1 mm thick) was coated with the polyimide-modified silicone resin, the fluororesin, the polyimide resin, and the silicone resin shown in Table 1 and heated at a predetermined temperature for a predetermined time to prepare a sample sheet. Abrasion resistance-Taber abrasion test Abrasion wheel CS5, after 3000 rotations under a load of 1 kg, the weight difference before and after the test is measured. The allowable weight of wear is 3 mg or less. A toner release test was conducted by the following method.

Mold releasability-toner rank test 250 μm thick Mylar sheet with polyimide-modified silicone resin and fluororesin, polyimide resin shown in Table 1
After applying a silicone resin and heating it at a predetermined temperature for a predetermined time, a resin coated mylar 30 was obtained.

Next, the toner (Ricoh cyan toner on one side is
Type 4100) transferred Al Mylar 31 (toner
Al is coated on one side of mylar as an electrode during transfer
Prepared). Here on Al Mylar
Weight of 0.5 g / cm ²Is. These are shown in Figure 5.
As shown, to improve the adhesion between toner and resin
Silicone rubber sheet 33 (2mm thick) on the SUS plate
Installed between resin mylars and sandwiched between SUS plates 32,
10kg / cm using a laboratory simple press molding machine²5,
It was heated and pressurized under the conditions of 0 ° C. and 1 hr. 3kg after the test
/ Cm²Blow off the toner with air and leave the toner
The condition was visually evaluated as below.

[0059]   Releasability rank   Rank 8 Toner is very easily removed         7 It takes some time, but the toner is completely removed         6 A small amount (less than a few percent) of toner remains         About 5% to 1/3 of toner remains         4 1/3 to 2/3 toner remains         32/3 or more toner remains         2 Toner remains on the entire surface (present as toner particles)         1 Toner remains on the entire surface (they do not exist as toner particles, Fusion)   Release allowance is rank 7 or higher.

The results are shown in Table 1.

[0061]

[Table 1]

Examples 3 to 5 Synthesis of Polyimide-Modified Silicone Resin In a four-necked flask equipped with a dry nitrogen gas inlet tube, a condenser, a thermometer, and a stirrer, 791 g of dehydrated and purified N-methyl-2-pyrrolidone (NMP) was added. And vigorously stirring for 10 minutes while flowing nitrogen gas, and then 2,2-bis (4- (4-
Aminophenoxy) phenyl) propane (BAPP)
0.10 mol, diaminopolydimethylsiloxane 0.
10 mol was added and the system was heated to 60 ° C. and stirred until uniform. Next, the system was cooled to 5 ° C or lower in an ice water bath, 0.42 mol of trimellitic anhydride was added, and then stirring was continued for 3 hours. During this period, the flask was kept at 5 ° C or lower.
Then, the nitrogen gas introducing tube and the condenser were removed, a Dean-Stark tube filled with xylene was attached to the flask, and 198 g of xylene was added to the system. Change the oil bath to about 17
The generated water was removed from the system by heating to 5 ° C. After heating for 4 hours and no more water generation from the system, cool down,
The reaction solution was poured into a large amount of methanol to precipitate the resin. The solid content was filtered and dried under reduced pressure at 80 ° C. for 12 hours to remove the solvent to obtain a polyimide-modified silicone resin (Example 3).

Next, a completely similar method except that diaminopolymethylphenylsiloxane (Example 4) and diaminodiphenylsiloxane (Example 5) were used as siloxane raw materials instead of the side chain methyl groups of diaminopolydimethylsiloxane. Thus, a polyimide-modified silicone resin was obtained.

100 parts by weight of these resins are mixed with 100 parts of a solvent (methyl ethyl ketone / cyclohexanone = 2/1 wt).
It was diluted to 0 parts by weight, spray-coated on an aluminum tube (80φ), and dried by heating at 150 ° C. for 1 hour to obtain an intermediate transfer member. (20 μm thickness)

The friction coefficient of this intermediate transfer member was measured by the Euler belt method (load 100 g, friction partner PPC paper type 6000 manufactured by Ricoh Co., Ltd.) and calculated by the following equation. μ (friction coefficient) = (π / 2) × ln (measured value / load) The allowable friction coefficient is 0.2 to 0.4. The results are shown in Table 2.

[0066]

[Table 2]

Examples 6 and 7 100 parts by weight of the polyimide-modified silicone resin of Example 3 and 1 part by weight of organic peroxide (benzoyl peroxide (Example 6), dicumyl peroxide (Example 7))
Was added and diluted in a solvent in the same manner as in Example 3, and then a sample sheet was prepared by the same method as in Example 1. This was subjected to a Taber abrasion test in the same manner as in Example 1. In Example 3 as well, a Taber abrasion test was conducted at the same time. The results are shown in Table 3.

[0068]

[Table 3]

Example 8 Polyimide-modified silicone resin (X-22-8904; Shin-Etsu Chemical Co., Ltd.) 100 parts by weight cyclohexanone 500 parts by weight methyl ethyl ketone 500 parts by weight carbon black (Printex 90; Degussa) 0, 15, 22, 30, 45 parts by weight The above-mentioned carbon black was added to the surface layer forming component used in Example 2 and ball-milled for 72 hours. This was spray-coated to obtain a developing roller in the same manner as in Example 3. The film thickness of the surface layer is 15 μm.

The volume resistance of this developing roller is set to 100 V DC.
Was calculated using the following equation from the resistance value after 1 minute. Volume resistance R (Ω · cm) = (resistance measurement value R ′) × ln
{(2πL) / (a / b)} L; main electrode width (1 cm), a; intermediate transfer member diameter, b; bare tube diameter The volume resistance was measured at seven points in the length direction, and the average value was calculated. The results of the amount of carbon black added and the volume resistance are shown in FIG.

Next, this is mounted on the intermediate transfer device of FIG.
The toner primary transfer rate and the toner secondary transfer rate were measured. (Average of measurement at 3 points) The following members were used. Photoconductor; OPC belt photoconductor toner; Ricoh cyan toner type 4100 transfer material; Ricoh PPC paper type 6000 secondary transfer roller; conductive urethane sponge roller (10
⁹ Ω · cm). The following formula was calculated and the transfer rate was plotted against the volume resistance to obtain the result shown in FIG. Primary transfer rate = [(m / a on intermediate transfer member) / (m on OPC)
/ A)] × 100 (%) Secondary transfer rate = [(m / a on transfer material) / (m on intermediate transfer member)
/ A)] × 100 (%)

Example 9 Instead of the carbon black used in Example 8, conductive tin oxide (T1; manufactured by Mitsubishi Materials) 40, 60, 80
An intermediate transfer member was prepared in the same manner as in Example 8 except that the amount by weight was added, and the volume resistance was measured. Also, the maximum measured value,
The difference between the minimum values was calculated as a variation. Example 8
The resistance variation was calculated and compared. The results are shown in Fig. 8. It can be seen that the resistance variation of tin oxide is small even within the range where the resistance variation of carbon black is large.

Examples 10 to 12 To 100 parts by weight of the tin oxide used in Example 9, 1 part by weight of a silane coupling agent (listed in the table) was added, and the mixture was stirred for 5 minutes with a high-speed mixer to obtain tin oxide. A silane coupling agent is attached to the surface. Then take it out from the high speed mixer 1
It was dried at 50 ° C. for 1 hour. 60 parts by weight of this surface-treated tin oxide was added to 100 parts by weight of polyimide-modified silicone resin (X-22-8904; Shin-Etsu Chemical Co., Ltd.),
An intermediate transfer drum was produced in the same manner as in Example 9. Transfer dust evaluation method This intermediate transfer drum is mounted on the image forming apparatus shown in FIG. 4, and a 1-dot black line when a test image is output is mounted on a microscope VH591 equipped with a 200 × lens.
It was observed at 0 (manufactured by KEYENCE CORPORATION), and the number of dust lines in one line in the visual field was counted. According to the number, the following ranking was performed. ◎: No dust toner ○: Less than 10 dust toner
Δ: 10 to 100 dust toner ×: 100 or more dust toner Table 4 shows the results.

[0074]

[Table 4]

It can be seen that the transfer dust is improved by the surface treatment of 60 parts by weight of tin oxide for the addition amount of tin oxide.

[0076]   Examples 13-18   Preparation of rubber layer   Rubber layer A forming component Silicone rubber (SH831U; Torre silicone) 100 parts by weight 25 parts by weight of carbon black / thermal black (manufactured by Asahi Carbon Co., Ltd.) Vulcanizing agent (C8; Shin-Etsu Chemical) 2 parts by weight

[0077]   Rubber layer B forming component Butyl rubber (Butyl 268 (trade name) made by Japan Synthetic Rubber) 100 parts by weight 35 parts by weight of carbon black / thermal black (manufactured by Asahi Carbon Co., Ltd.) Zinc white 5 parts by weight Stearic acid 1 part by weight Vulcanization additive (including sulfur) 7.5 parts by weight

[0078]   Rubber layer C forming component EPDM (EP21 (trade name) manufactured by Japan Synthetic Rubber) 100 parts by weight 35 parts by weight of carbon black / thermal black (manufactured by Asahi Carbon Co., Ltd.) Zinc white 5 parts by weight Stearic acid 1 part by weight Vulcanization additive (including sulfur) 7.5 parts by weight

[0079]   Rubber layer D forming component Nitrile butadiene rubber (N220S made by Japan Synthetic Rubber) 100 parts by weight Zinc white 5 parts by weight Stearic acid 1 part by weight Vulcanization additive (including sulfur) 7.5 parts by weight

Rubber layer E forming component Epichlorohydrin rubber (Epichromer CG manufactured by Daiso) 100 parts by weight Zinc white 5 parts by weight Stearic acid 1 part by weight Additive for vulcanization (including sulfur) 7.5 parts by weight These rubber layer components After kneading by a predetermined method, a rubber layer was molded on the aluminum tube by a predetermined method.
(Steam vulcanization method, rubber layer thickness is shown in the table)

[0081]   Intermediate transfer member surface layer forming component Polyimide-modified silicone resin (X-22-8904; Shin-Etsu Chemical)                                                           100 parts by weight Cyclohexanone 500 parts by weight Methyl ethyl ketone 500 parts by weight Tin oxide (surface treated product of Example 10) 60 parts by weight

Then, an intermediate transfer member was prepared on the rubber layer in the same manner as in Example 9 except that the above surface layer components were used. The effective hardness of these intermediate transfer bodies, volume resistance (average value of 7 places), maximum value-minimum value of volume resistance and these intermediate transfer drums are shown in FIG.
When an image output test was carried out by using the OHP sheet (OHP film type 2 manufactured by Ricoh) attached to the image forming apparatus shown in FIG. The results are shown in Table 5.

[0083]

[Table 5]

[0084]

As described above, according to the first aspect of the present invention, a plurality of visible color developed images sequentially formed on the image carrier by toner are sequentially transferred on the intermediate transfer member which runs endlessly. In an intermediate transfer device for performing primary transfer by superimposing and secondary transferring the primary transfer image on the intermediate transfer member onto a transfer material at once, at least the surface of the intermediate transfer member is made of a material containing a polyimide-modified silicone resin. With the above-mentioned intermediate transfer device, it is possible to obtain an intermediate transfer device having excellent wear resistance and releasability.

According to the second aspect of the invention, the intermediate transfer device of the first aspect is characterized in that the silicone component in the polyimide-modified silicone resin of the first aspect comprises a dimethylsiloxane monomer component. It is possible to obtain the intermediate transfer device in which the friction coefficient of the transfer member is reduced and the surface characteristics are further improved.

According to the invention of claim 3, the silicone component in the polyimide-modified silicone resin of claim 1 is cross-linked by a silicone cross-linking agent. It is possible to obtain an intermediate transfer device having further improved properties.

According to the invention of claim 4, the volume resistance of the layer made of the material containing the polyimide-modified silicone resin of claim 1 is 10 ⁸ Ω · cm or more and 10 ¹² Ω · c.
According to the intermediate transfer device of the third aspect, the intermediate transfer device having an improved toner transfer rate can be obtained.

According to the invention of claim 5, conductive tin oxide is added to a layer made of a material containing the polyimide-modified silicone resin of claim 4. The transfer device can provide an intermediate transfer device with improved resistance stability.

According to the invention of claim 6, the conductive tin oxide according to claim 5 is surface-treated with a silane coupling agent. An improved intermediate transfer device can be obtained.

According to the invention of claim 7, the intermediate transfer member according to claim 1 is composed of a plurality of layers, and a surface layer composed of a material containing at least a polyimide-modified silicone resin and a layer below it are 10 ¹² An excellent intermediate transfer device capable of coping with various transfer materials is obtained by the intermediate transfer device according to claim 1, which has a rubber base material having a volume resistance of Ω · cm or less and an effective hardness of JIS A 95 degrees or less. be able to.

According to an eighth aspect of the present invention, the rubber base material according to the seventh aspect is a mixture of either one or both of a nitrile-butadiene rubber and an ebichlorohydrin rubber. With the intermediate transfer device of No. 7, it is possible to obtain an intermediate transfer device in which the resistance of the rubber layer is stable.

According to a ninth aspect of the present invention, there is provided an image forming layer apparatus comprising at least charging, exposure, developing, intermediate transfer, cleaning and charge eliminating devices and an electrophotographic photosensitive member, wherein the intermediate transfer device is provided. Any one of claims 1 to 8
With the image forming apparatus characterized by being the intermediate transfer device described in the item 1, it is possible to stably obtain a high-quality image with excellent transfer rate and less transfer dust over time.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an outline of intermediate transfer according to the present invention.

FIG. 2 is a schematic diagram of an example in which an intermediate transfer belt is used as an intermediate transfer member.

FIG. 3 is a configuration diagram of an image forming apparatus using an intermediate transfer drum as an intermediate transfer member.

FIG. 4 is a configuration diagram of an image forming apparatus using an intermediate transfer belt as an intermediate transfer member.

FIG. 5 is an explanatory diagram for a toner release test method for the intermediate transfer member of the present invention.

FIG. 6 is an explanatory diagram of the relationship between the amount of carbon black and the volume resistance of the surface layer of the transfer body of the present invention.

FIG. 7 is an explanatory diagram of the results of plotting the transfer rate of the transfer body of the present invention against the volume resistance.

FIG. 8 is an explanatory diagram of resistance characteristics of a tin oxide mixed layer in measurement of volume resistance of the transfer body of the present invention.

[Explanation of symbols]

11 Intermediate transfer drum 12 Backup roller 13, 23 Transfer roller 15, 26 Transfer material (paper) 18 photoconductor 19 Development Department 20 charger 21 exposure means 24 Static eliminator before cleaning 25 Cleaning means 27 toner

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H030 BB02 BB23 BB42 BB63                 2H200 FA02 GA23 GA24 GA34 GA47                       GA50 GA61 GB02 GB11 GB22                       GB25 HA02 HA12 HA28 HB03                       HB12 JA02 JC02 JC03 JC12                       JC13 JC15 JC16 JC17 LB02                       LB09 LC03 LC04 LC10 MA03                       MA11 MA12 MA14 MA20 MB04                       MC02 MC06 MC08

Claims (9)

[Claims] 1. A plurality of visible color-developed images sequentially formed on an image bearing member by toner are sequentially superimposed and primary-transferred onto an endlessly traveling intermediate transfer member, and the primary transfer on the intermediate transfer member is performed. An intermediate transfer device for secondarily transferring an image onto a transfer material at a time, wherein at least the surface of the intermediate transfer member is made of a material containing a polyimide-modified silicone resin. 2. The intermediate transfer device according to claim 1, wherein the silicone component in the polyimide-modified silicone resin is composed of a dimethylsiloxane monomer component. 3. The intermediate transfer device according to claim 1, wherein the silicone component in the polyimide-modified silicone resin is crosslinked with a silicone crosslinking agent. 4. The intermediate transfer device according to claim 3, wherein the volume resistance of the layer made of a material containing a polyimide-modified silicone resin is in the range of 10 ⁸ Ω · cm or more and 10 ¹² Ω · cm or less. . 5. The intermediate transfer device according to claim 4, wherein conductive tin oxide is added to a layer made of a material containing a polyimide-modified silicone resin. 6. The intermediate transfer device according to claim 5, wherein the conductive tin oxide is surface-treated with a silane coupling agent. 7. An intermediate transfer member is composed of a plurality of layers, and a surface layer made of a material containing at least a polyimide-modified silicone resin and an underlying layer have a volume resistance of 10 ¹² Ω · cm or less and an effective hardness. The intermediate transfer device according to claim 1, comprising a rubber base material having a JISA of 95 degrees or less. 8. The intermediate transfer device according to claim 7, wherein the rubber base material is one of nitrile-butadiene rubber and / or shrimp chlorohydrin rubber or a mixture of both. 9. An image forming layer apparatus comprising at least charging, exposure, developing, intermediate transfer, cleaning, charge eliminating devices and an electrophotographic photosensitive member, and the image forming layer device according to claim 1. An image forming apparatus using an intermediate transfer device.