JPH0443581B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to improvements in image holding members for holding electrostatic or toner images. BACKGROUND OF THE INVENTION Electrostatic or toner images are formed by various electrophotographic processes. Image holding members that hold formed images include image holding members that have a photoconductive layer and are called electrophotographic photoreceptors, and image holding members that do not have a photoconductive layer. Electrophotographic photoreceptors have various configurations depending on the type of electrophotographic process to which they are applied. Typical electrophotographic photoreceptors include a photoreceptor in which a photoconductive layer is formed on a support, and a photoreceptor in which a photoconductive layer and an insulating layer thereof are laminated as an image holding layer.
Widely used. A predetermined electrophotographic process is applied to the electrophotographic photoreceptor to form an electrostatic image, and this electrostatic image is developed and visualized. However, the surface layer of such an image-bearing material is subjected to various treatments in an electrophotographic process, such as electromechanical treatments such as charging, exposure, development, transfer, and cleaning. Therefore, in order to use the photoreceptor repeatedly, it is important that the surface layer has strong durability against these treatments. In particular, durability against surface damage caused by cleaning is an important item. On the other hand, in addition to the residual toner after transfer, decomposition products caused by paper dust from the transfer paper and ozone generated by corona charging adhere to the surface layer, so if the cleaning process is insufficient, the residual toner will This causes adhesion to the layer and a decrease in surface resistance, thus causing deterioration in image quality. Therefore, in order to satisfy the repeated durability, it is necessary that the surface layer of the image holding member has good cleaning performance. Conventionally, attempts have been made to meet these demands by adding substances that impart lubricity to the surface layer. Such substances include common coating surface modifiers, ie, leveling agents, silicone oils, and the like. There is also a method of dispersing Teflon powder or the like. However, general surface modifiers have poor compatibility with the components of the coating liquid to which they are added, so they migrate or ooze out onto the surface layer during long-term use, making it difficult to maintain their effects. It was hot. In addition, when the surface layer itself forms a photoconductive layer, the surface modifier has poor compatibility with the photoconductive substance, and furthermore, it tends to become a trap for the movement of the carrier due to photogeneration, and it is difficult to repeat the electrophotographic process. There was a tendency for the residual charge to increase. On the other hand, a surface layer in which Teflon powder or the like is dispersed has problems such as poor dispersibility, decreased transparency, and carrier trapping. [Problems to be Solved by the Invention] An object of the present invention is to provide an image holding member having a surface layer that is transparent, has excellent surface lubricity and mold releasability, and has extremely good cleaning properties. Another object of the present invention is to have excellent repeated durability.
An object of the present invention is to provide an image holding member whose surface layer is less damaged. Still another object of the present invention is to provide an image holding member that does not accumulate residual charge and can always produce high quality images in repeated electrophotographic processes. [Means for Solving the Problems] That is, the present invention provides silicones selected from the following general formulas () and () and the following general formula ().
An image holding member characterized by having a surface layer containing a silicone-based comb-shaped graft polymer obtained by copolymerizing a modified silicone which is a condensation reaction product with silicone and a compound having a polymerizable functional group. It is. (R ₁ to R ₇ represent groups selected from alkyl groups and aryl groups, R ₈ to R ₁₀ represent groups selected from hydrogen atoms, halogen atoms, alkyl groups, and aryl groups, and R ₁₁ represents groups selected from alkyl groups and aryl groups. X represents a group selected from halogen atoms and alkoxy groups, n ₁ and n ₂ represent positive integers, and n ₃ represents 1 to 3.) Silicone used in the present invention The comb-type graft polymer has a structure in which silicone-containing side chains are dangling from the main chain in the form of branches. R ₁ represented by the above general formulas () and (),
R ₂ , R ₃ , R ₄ , R ₅ , R ₆ and R ₇ are an alkyl group or an aryl group, and these may have a substituent. For example, the alkyl group is a methyl group, ethyl group, propyl group, butyl group, etc., and may be substituted with a halogen atom or the like. Further, the aryl group includes a phenyl group, a naphthyl group, etc., and may have a substituent. Preferred are methyl group and phenyl group. n ₁ and n ₂ are positive integers indicating the average degree of polymerization, 1 or more
It is preferably 1000 or less, particularly 10 or more and 500 or less.
R ₈ , R ₉ , and R ₁₀ in the general formula () are hydrogen atoms, and the halogen atoms are fluorine, chlorine, bromine, and iodine. Both the alkyl group and the aryl group may have a substituent, and examples of the alkyl group include a methyl group, ethyl group, propyl group, and butyl group. In addition, as an aryl group, a phenyl group,
Such as naphthyl group. R ₈ , R ₉ and R ₁₀ are preferably hydrogen atoms. R ₁₁ is an alkyl group such as a methyl group, ethyl group, propyl group, butyl group, and may be substituted with a halogen atom or the like. Further, the aryl group is, for example, a phenyl group, a naphthyl group, etc., and may have a substituent. Preferred are methyl group and phenyl group. X is a halogen atom such as fluorine, chlorine, bromine or iodine, preferably a chlorine atom. Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, and may have a substituent. Preferred are methoxy group, ethoxy group, and 2-methoxy-ethoxy group. _n3 is an integer from 1 to 3. Specific examples of general formulas () to () are shown below. Specific example No. of general formula (). Specific example No. of general formula (). Specific example of general formula () Silicones represented by the general formula () and general formula () have both () and () combined with the general formula ().
may be reacted with silicone to form a modified silicone. The condensation reaction of the general formula () and () with the general formula () proceeds very smoothly according to ordinary organic chemical reaction operations, for example, in JP-A-58
-167606, stable modified silicones can be obtained by controlling the reaction molar ratio and reaction conditions. Compounds with polymerizable functional groups include macromonomers consisting of polymerizable monomers that do not have silicon atoms or relatively low molecular weight polymers with a molecular weight of about 1,000 to 10,000 that have a polymerizable functional group at the end. Can be mentioned. As a polymerizable monomer,
Examples of olefin compounds include low molecular weight linear unsaturated hydrocarbons such as ethylene, propylene and butylene, vinyl halides such as vinyl chloride and vinyl fluoride, vinyl esters of organic acids such as vinyl acetate, styrene and styrene substituted and other vinyl aromatic compounds such as vinylpyridine and vinylnaphthalene, acrylic acid, methacrylic acid and their esters, amides and derivatives of acrylic acid, methacrylic acid including acrylonitrile, N-vinylcarbazole, N-vinylpyrrolidone and N- such as N-vinylcaprolactam
Examples include vinyl compounds and vinyl silicon compounds such as vinyltriethoxysilane. Disubstituted ethylenes can also be used, examples being vinylidene fluoride, vinylidene chloride, and the like. Furthermore, esters of maleic anhydride, maleic acid and fumaric acid, etc. can also be used. Further, the polymerizable monomers can be used alone or in combination of two or more types. Radical polymerization and ionic polymerization such as solution polymerization, suspension polymerization, and bulk polymerization can be applied as the polymerization method for silicone-based comb-shaped graft polymers.
Radical polymerization by solution polymerization is convenient and preferred. The copolymerization ratio is 5 to 5 as the content of modified silicone.
100% by weight is preferred, and 10 to 70% by weight is more preferred. The number average molecular weight of the obtained polymer is preferably 500 to 100,000, particularly preferably 1,000 to 50,000. The form of the surface layer containing the silicone-based graft polymer in the present invention is (1) When the surface layer itself is a photoconductive layer, a photoconductive polymer or photoconductive powder is dispersed or dissolved in a binder resin. It is formed by applying and drying a coating solution; and (2) when the surface layer is formed on the photoconductive layer, (a) the surface layer is a relatively thin film (about 0.1 to 10μ) and image formation is possible. (b) The surface layer is a relatively thick film (approximately 10 to 50 μm) and the image forming process is different from (1) above. Since the silicone-based graft polymer in the present invention has such a structure, the above-mentioned surface layer form (1)
In (2), the compatibility with the coating solution containing the binder resin for forming the surface layer is excellent, and therefore the resulting coating film has good transparency and does not migrate or bleed onto the surface layer. It has a long-lasting effect without causing any side effects, and since the silicone-containing branches have excellent interfacial migration properties, a small amount of addition achieves surface modification, imparts lubricity, and provides good cleaning performance. Demonstrate. Therefore, residual toner on the surface layer of the image holding member after transfer, paper dust from the transfer paper and decomposition products caused by ozone generated by corona charging are effectively removed by cleaning to prevent contamination of the surface layer of the image holding member. It is extremely effective in achieving high potential stability and image quality stability during repeated durability. In addition, in the surface layer form (1), as mentioned above, due to the interfacial migration of the silicone-containing branches of the silicone-based graft polymer, there is virtually no graft polymer in the bulk of the photoconductive layer, and the photoconductive layer is Since carrier transport is not hindered in any way and no traps are formed, stable charging properties can be obtained without accumulation of residual charges due to repeated electrophotographic processes. The specific form of the form (1) of the surface layer is shown below. (1)-1 Those containing a photoconductive polymer (1)-2 Those in which photoconductive particles are dispersed or dissolved in a binder (1)-3 A charge generation layer containing a charge generation substance and a charge transport substance Examples include those comprising a charge transport layer containing. The photoconductive layer in the form (2) of the surface layer is the one described in (1)-1 above.
〜(1)-3 etc. The photoconductive polymer in form (1) of the surface layer may be formed by condensation of a saturated aliphatic aldehyde with a primary aromatic amine such as aniline, as described in, for example, U.S. Pat. No. 3,244,517. High molecular weight polymers or resins produced: U.S. Pat.
High molecular weight polymers or resins prepared by condensation of certain aromatic amines containing aromatic heterocycles with unsaturated aldehydes, acrolein or alkyl-substituted acrolein, such as those described in US Pat. No. 3,163,531. ; low molecular weight condensation polymers prepared by condensation of formaldehyde or paraformaldehyde with anthracene or N-alkyl carbazole as described in U.S. Pat. No. 3,240,597; as described in U.S. Pat. No. 3,770,428; and poly-N-vinyl as described in U.S. Pat. No. 3,037,861; Examples include carbazole polymers. As photoconductive powder, amorphous silicon,
Inorganic photoconductive particles such as selenium, selenium-tellurium alloy, selenium-arsenic alloy, cadmium sulfide zinc oxide; copper phthalocyanine, perinone pigment, thioindigo, quinacridone, perylene pigment, anthraquinone pigment, azo pigment, bisazo pigment ,
Examples include organic conductive particles such as cyanine pigments. Examples of dyes include methyl violet,
Examples include triphenylmethane dyes such as brilliant green and crystal violet, thiazine dyes such as methylene blue, quinone dyes such as quinizarin, cyanine dyes, pyrylium salts, thiapyrylium salts, benzopyrylium salts, etc., and are also used as charge-generating substances. . As the charge transport substance, pyrene, N-ethylcarbazole, N-isopropylcarbazole, N
-Methyl-N-phenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3
-methylidene-10-ethylphenothiazine, N,
N-diphenylhydrazino-3-methylidene-10
-Ethylphenoxazine, p-diethylaminobenzaldehyde-N,N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-
α-Naphthyl-N-phenylhydrazone, p-pyrrolidinobenzaldehyde-N,N-diphenylhydrazone, 1,3,3-trimethylindolenine-∞-aldehyde-N,N-diphenylhydrazone, p-diethylbenzaldehyde -Hydrazones such as 3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, 1-
Phenyl-3-(p-diethylaminostyryl)-
5-(p-diethylaminophenyl)pyrazoline,
1-[quinolyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-(p-diethylaminostyryl)-5-( p-diethylaminophenyl)pyrazoline, 1-[6-methoxy-pyridyl(2)]-3-(p-diethylaminostyryl)-
5-(p-diethylaminophenyl)pyrazoline,
1-[Pyridyl(3)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[Lepidyl(2)]-3-(p-diethylaminostyryl)-5-( p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-
(p-diethylaminostyryl)-4-methyl-5
-(p-diethylaminophenyl)pyrazoline,
1-[pyridyl(2)]-3-(α-methyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(p
-diethylaminostyryl)-4-methyl-5-
(p-diethylaminophenyl)pyrazoline, 1
-Phenyl-3-(α-benzyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, spiropyrazoline and other pyrazolines, 2-(p-diethylaminostyryl)-
6-diethylaminobenzoxazole, 2-
Oxazole compounds such as (p-diethylaminophenyl)-4-(p-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, 2
Thiazole compounds such as -(p-diethylaminostyryl)-6-diethylaminobenzothiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,N -diethylamino-2-methylphenyl)heptane, 1,
Polyarylalkanes such as 1,2,2-tetrakis(4-N,N-dimethylamino-2-methylphenyl)ethane and the like can be used. In addition, as binders, polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic esters, methacrylic esters, butadiene, polyvinyl acetal,
Examples include various polymers such as polysulfone, polyphenylene oxide, polyurethane, cellulose ester, cellulose ether, phenoxy resin, silicon resin, and epoxy resin. The amount of the silicone graft polymer added is suitably 0.01 to 10%, particularly preferably 0.05 to 5%, based on the solid weight of the surface layer. Addition amount is 0.01
If it is less than %, sufficient surface modification effect cannot be obtained;
If it exceeds 10%, the graft polymer will exist not only on the surface of the coating film but also in the bulk, which may cause whitening due to compatibility with the resin and photoconductive substance that are the main components of the surface layer. Residual charge buildup occurs during repeated electrophotographic processes. When manufacturing the image holding member of the present invention, the substrate may be metal such as aluminum or stainless steel;
Cylindrical cylinders or films of paper, plastic, etc. are used. On top of these substrates,
Subbing layer (adhesive layer) with barrier and subbing functions
can be provided. A coating method in which the silicone-based graft polymer is added to a solution in which the composition used for forming the surface layer is dispersed or dissolved in a solvent is applied onto the substrate or the photoconductive layer, by dip coating;
An image holding member is obtained by coating and drying using a coating method such as a spray coating method, a spinner coating method, a bead coating method, a blade coating method, or a curtain coating method. The present invention will be further explained below with reference to Examples. Synthesis example (silicone-based comb-shaped silicone of sample No. h in Table 1) Silicone (0.01 mol) of specific example No. 26 (n ₂ : average 300) of general formula () and 0.012 mol of pyridine were dissolved in 400 ml of diethyl ether. 10% of the compound of specific example No. 65 of general formula () (0.005 mol) was added to the solution.
A diethyl ether solution was gradually added dropwise at room temperature over 20 minutes. The reaction proceeded immediately and white crystals of pyridine hydrochloride were precipitated. After the dropwise addition was completed, the mixture was further stirred at room temperature for 1 hour, and the crystals of pyridine hydrochloride were removed by filtration. Next, this filtrate was placed in a separatory funnel, and 500 ml of water was added thereto, and the mixture was thoroughly shaken and washed with water. The water washing liquid separatory funnel was allowed to stand still to separate the upper ether layer and the lower aqueous layer, and anhydrous sodium sulfate was added to the obtained ether layer and left overnight at room temperature for dehydration. Thereafter, anhydrous sodium sulfate was removed by filtration, and the resulting filtrate was distilled under reduced pressure to remove ether, yielding 150 g of a colorless and transparent modified silicone. Next, 30 parts of the modified silicone obtained, 70 parts of styrene
1 part, 0.25 parts of azobisisobutyronitrile (hereinafter referred to as AIBN), and 60 parts of toluene in a condenser,
Place in a flask equipped with a stirrer at 80 °C in a nitrogen atmosphere.
The reaction was carried out at a temperature of 24 hours. After the reaction was completed, the contents of the flask were poured into a large amount of methanol to precipitate a polymer, which was then filtered to obtain a polymer. After drying under reduced pressure, 78 parts of a uniform white oily silicone-based graft copolymer was obtained. Other sample numbers shown in Table 1 were also synthesized. Table 1 Composition of silicone comb-shaped graft polymer

【table】

[Table] Example 1 Electrophotographic zinc oxide powder (product name SAZEX4000,
After thoroughly dispersing 100 parts (by weight, same hereinafter) (manufactured by Sakai Chemical), 0.5 parts of rose bengal as a pigment, 5 parts of methanol, and 100 parts of toluene in a ball mill, the solvent was removed by absorption filtration. To the dye-sensitized zinc oxide, 20 parts of butyral resin (trade name BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a binder, 20 parts of blocking isocyanate, 0.4 parts of trimethanolamine as a hardening agent, 50 parts of methyl ethyl ketone as a solvent,
20 parts of ethanol was added and the mixture was well dispersed again using a ball mill to obtain a photoconductive paint. This was applied by dip coating to an 80φ x 300mm aluminum cylinder that had been subjected to undercoat treatment, and was heated and cured at 120℃ for 30 minutes.
A 25 μm photosensitive layer was formed. Next, conductive TiO ₂ (trade name
ECT-62 (manufactured by Titan Industries) was well dispersed in a ball mill to obtain a protective layer coating solution. Further, 2 parts of silicone-based comb-shaped graft polymer of sample No. a was added as a solid content to this coating solution to prepare a paint. This was coated by dip coating on the photosensitive layer, and heated at 100°C.
Dry for 5 minutes to obtain a 2μ protective layer. This is sample 1
shall be. Similarly, a photoreceptor prepared using the silicone comb-shaped graft polymer of sample No. b was used as sample 2.
And so. Furthermore, for comparison, a sample without the surface modifier was prepared in the same manner as above, and this was designated as Sample 3. These photoreceptors are charged with -5.5kV corona,
Durability was evaluated using an electrophotographic process consisting of image exposure, dry toner development, toner transfer to plain paper, and cleaning with a urethane rubber blade. The results are shown in Table 2. The evaluation environment is 32.5
℃, RH90%.

[Table] Example 2 100 parts of CdS powder (parts by weight, same hereinafter), 15 parts of diallyl phthalate resin (trade name: Daiso Tap, manufactured by Osaka Soda) as a binder, and 0.5 parts of benzoyl peroxide were mixed with methyl ethyl ketone (MEK). It was dissolved in a mixed solvent of equal amounts of and xylene, and thoroughly mixed using a roll mill to obtain a photoconductive paint. This is 80×
Apply to 300mm Al cylinder by dipping method and heat at 120℃.
It was cured for 10 minutes to form a 40μ thick photoconductive layer. Next, a diallyl phthalate resin (same as above) solution containing 3% by weight of benzoyl peroxide was applied on top of this, and the mixture was heated to 10°C at 120°C.
The resin layer was cured for 10 minutes to form a 10μ thick resin layer. Next, urethane acrylate resin (product name:
Sonne (manufactured by Kansai Paint Co., Ltd.) was applied and cured by irradiation with ultraviolet light to form a 10μ thick layer. Furthermore, polysulfone resin (product name: Udel)
P1700UCC) was dissolved in 40 parts of monochlorobenzene and 30 parts of MEK, and 1.5% of the silicone comb-shaped graft polymer of sample a was dissolved in this as a solid content.
Added part. Coat this solution on the above layer and heat it at 20°C.
A surface layer of 5 μm was formed by drying for 5 minutes. This is designated as sample 4. Furthermore, for comparison, a sample without the silicone comb-shaped graft polymer was prepared in the same manner as above, and this was designated as sample 5. The samples thus obtained were evaluated using an electrophotographic copying machine consisting of primary +6kV corona charging, secondary AC corona charging, simultaneous image exposure, full-surface light irradiation, dry toner development, transfer to plain paper, and cleaning with a urethane rubber blade. did. The results are shown in Table 3. The evaluation environment was 32.5℃ and RH90%.

[Table] Example 3 10 parts (parts by weight, the same applies hereinafter) of New Zealand-produced lactose casein were weighed out and dispersed in 90 parts of water, and then 1 part of aqueous ammonia was added to dissolve it.
Separately, 3 parts of hydroxypropyl methylcellulose resin (trade name: Metrose 60SH50, manufactured by Shin-Etsu Chemical) was dissolved in 20 parts of water, and then the two were mixed to prepare a coating solution for the undercoat layer. This liquid was applied to an 80φ x 300mm Al cylinder by dipping and dried at 80°C for 10 minutes to form a 2μ thick undercoat layer. Next, add 10 parts of the disazo pigment with the following structural formula. Cellulose acetate butyrate resin (product name: CAB-
381 (manufactured by Eastman Chemical) and 60 parts of cyclohexanone were dispersed for 20 hours using a sand mill device using 1φ glass beads. Add 100 parts of methyl ethyl ketone to this dispersion, dip coat it onto the undercoat layer, heat dry at 100°C for 10 minutes,
A charge generating layer was formed with a coating weight of 0.1 g/cm ² . Next, add 10 parts of a hydrazone compound having the following structural formula. and 10 parts of methyl methacrylate-styrene copolymer resin (trade name MS-600, manufactured by Nippon Steel Chemical Co., Ltd.) were dissolved in 55 parts of monochlorobenzene. To this liquid, 1.0 part of the silicone graft polymer of sample a was added as solid content. This was coated on the charge generation layer and dried with hot air at 100° C. for 1 hour to form a charge transport layer with a thickness of 16 μm. This was designated as sample 6. Photoreceptors similarly prepared using the silicone-based comb-shaped graft polymers of Sample Nos. b to m were designated as Samples 7 to 18, respectively. Furthermore, for comparison, a sample without the silicone comb-shaped graft polymer was prepared in the same manner as above, and this was designated as sample 19. The thus obtained photoreceptor was installed in an electrophotographic copying machine that has -5.6kV corona charging, image exposure, dry toner development, toner transfer to plain paper, cleaning process using a urethane rubber blade, etc. at 32.5℃ and RH 90%. Image durability was evaluated under environmental conditions. The results are shown in Table 4.

[Table] Example 4 10 parts (parts by weight, the same applies hereinafter) of New Zealand-produced lactose casein were weighed out and dispersed in 90 parts of water, and then 1 part of aqueous ammonia was added to dissolve it.
Separately, 3 parts of hydroxypropyl methylcellulose resin (trade name: Metrose 60SH50, manufactured by Shin-Etsu Chemical) was dissolved in 20 parts of water, and then the two were mixed to prepare a coating solution for the undercoat layer. This liquid was applied to an 80φ x 300mm Al cylinder by dipping and dried at 80°C for 10 minutes to form a 10μ thick undercoat layer. Next, 12 parts of a pyrazoline compound having the following structural formula,
polysulfone resin (Product name: Udel P-1700 manufactured by UCC) 10 parts was dissolved in 52 parts of monochlorobenzene. This liquid was dip coated onto the undercoat layer and dried at 100°C for 1 hour to form a charge transport layer of 16μ. Next, add 10 parts of the bisazo pigment with the structural formula below. 5 parts of polyvinyl butyral resin (trade name: Eslec BM-S, manufactured by Sekisui Chemical Co., Ltd.) and 30 parts of butyl acetate were dispersed for 20 hours using a sand mill apparatus using 1φ glass beads. Add 40% ethanol to this dispersion.
0.3 parts of the silicone polymer of Sample A and Sample A were added as a solid content and applied by dip coating onto the charge transport layer, followed by drying at 100° C. for 5 minutes to form a charge generation layer with a thickness of 0.15 μm. This was designated as sample 20. Photoreceptors similarly prepared using the silicone comb-shaped graft polymers of Sample Nos. b to m were designated as Samples 21 to 32, respectively. Furthermore, for comparison, a photoreceptor without the addition of a silicone comb-shaped graft polymer was prepared in the same manner as above, and this was designated as Sample 33. The thus obtained photoreceptor was attached to an electrophotographic copying machine that has +5.6 kV corona charging, image exposure, dry toner development, toner transfer to plain paper, cleaning process using a urethane rubber blade, etc.
Evaluation was conducted in an environment of 32.5℃ and RH90%. The results are shown in Table 5.

[Table] Comparative example Silicone oil instead of silicone-based comb polymer (product name: KF96 manufactured by Shin-Etsu Silicone)
Sample 34 is a photoreceptor prepared in the same manner as in Example 1, except that 1.0 part of the solid content was used. Samples 35, 36, and 37 were photoreceptors prepared in the same manner as in Examples 2, 3, and 4, except that the above silicone oil was used instead of the silicone-based comb-shaped graft polymer used in Examples 2, 3, and 4. . The durability of these samples was evaluated under the same conditions as in each example, but the background fog was significant, and the degree of fog increased with repeated copying.
When samples 34, 35, 36, and 37 were observed one month after they were prepared, it was found that the silicone oil had migrated to the surface layer and stood out in the form of stains. On the other hand, samples 1, 2, 4, and 6 to which silicone-based comb-shaped graft polymer was added
-18 and 20-32 showed no such change over time, and showed the same appearance and characteristics as the initial stage. Example 5 The friction force between the urethane blade and the surface layer was measured for Samples 1 to 37. The results are shown in Table 6.

[Table] Example 6 The dark potential (V _D ) and bright potential (V _L ) at the initial stage and after 3,000 sheets of durability were measured under the same image development conditions as in the durable image evaluation in Examples 1, 3, and 4. Potential fluctuations during durability were observed. Some of the results are shown in Table 7.

〔Effect of the invention〕

The electrophotographic photoreceptor of the present invention has excellent surface lubricity and mold release properties, and extremely good cleaning properties.
Moreover, it has excellent durability against repeated electrophotography, and high-quality images can always be obtained without accumulation of residual charges in repeated electrophotographic processes.

Claims (1)

[Claims] 1. Copolymerization of a modified silicone, which is a condensation reaction product of a silicone selected from the following general formulas () and (), and a silicone of the following general formula (), and a compound having a polymerizable functional group. An image holding member comprising a surface layer containing a silicone-based comb-shaped graft polymer obtained by (R ₁ to R ₇ represent groups selected from alkyl groups and aryl groups, R ₈ to R ₁₀ represent groups selected from hydrogen atoms, halogen atoms, alkyl groups, and aryl groups, and R ₁₁ represents groups selected from alkyl groups and aryl groups. X represents a group selected from halogen atoms and alkoxy groups, n ₁ and n ₂ represent positive integers, and n ₃ represents 1 to 3. On the surface layer of the holding member
The image holding member according to claim 1, which contains 0.01 to 10% by weight. 3. The image holding member according to claim 1, wherein the surface layer is formed on a photoconductive layer. 4. The image holding member according to claim 1, wherein the surface layer itself is a photoconductive layer.