JPH0549102B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an electrophotographic photoreceptor that can be widely used in the electrophotographic field such as electrophotographic copying machines, laser beam printers, CRT printers, and electrophotographic engraving systems. [Prior Art] Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have conventionally been used as photoconductive materials for electrophotographic photoreceptors. On the other hand, organic photoconductive materials such as polyvinylcarbazole, oxadiazole, and phthalocyanine have advantages over inorganic photoconductive materials, such as non-pollution and high productivity, but their low sensitivity has made it difficult to put them into practical use. For this reason, several sensitization methods have been proposed, and the use of a functionally separated photoreceptor in which a charge generation layer and a charge transport layer are laminated is known and put into practical use as an effective method. Of course, electrophotographic photoreceptors have
It is required to have predetermined sensitivity, electrical properties, and further optical properties depending on the electrophotographic process to which it is applied. In particular, for photoreceptors that can be used repeatedly, the surface layer of the photoreceptor, that is, the layer furthest from the substrate, is directly exposed to electrical and mechanical external forces such as corona charging, toner phenomenon, transfer to paper, and cleaning processing. Since these materials are added, durability against them is required. Specifically, durability is required against reductions in sensitivity and potential, increases in residual potential due to deterioration due to ozone generated during corona charging, and the occurrence of surface friction and scratches due to rubbing. In addition, adhesion of paper dust due to contact with paper is one of the causes of image fading under high humidity conditions, and toner filming and residual toner due to poor cleaning can significantly impair the resulting image. There is a need to form a photoreceptor surface that is not easily contaminated by these substances and is easily removed. Conventionally, various methods have been proposed to solve the above-mentioned drawbacks. As one such method, the use of polyarylate resin as a binder for the surface layer is being considered. Since polyarylate resin has good abrasion resistance, a photoreceptor using polyarylate resin as a binder in the surface layer has significantly improved durability against external mechanical forces. However, because the amount of abrasion of the surface layer decreases, cleaning performance of attached paper dust and residual toner becomes poor.
On the contrary, this will cause deterioration in image quality. In order to improve this problem, attempts have been made to impart lubricity and release properties to the surface layer, making it difficult for paper powder and residual toner to adhere to it and making it easier to clean. As a means for this, there is a method of adding a general coating film surface modifier, ie, a leveling agent, silicone oil, etc., and a method of dispersing Teflon powder. However, these common surface modifiers
Due to its poor compatibility with the components of the coating liquid to which it is added, it migrates or oozes out onto the surface layer during long-term use, making it difficult to maintain its effect. In addition, when the surface layer itself forms a photoconductive layer, the surface modifier has poor compatibility with the photoconductive substance, and is likely to become a trap for carrier movement due to photogeneration, resulting in repeated electrophotographic processes. There was a tendency for the residual charge to increase. On the other hand, problems such as poor dispersibility, decreased transparency, and carrier traps occurred in the surface layer in which Teflon or the like was dispersed. [Problems to be Solved by the Invention] The present invention solves the conventional problems and provides excellent surface lubricity and mold resistance, extremely good cleaning properties, excellent repeat durability, and The purpose is to provide an electrophotographic photoreceptor with less damage. Another object of the present invention is to provide an electrophotographic photoreceptor that does not accumulate residual charge during repeated electrophotographic processes and can always produce high-quality images. [Means and effects for solving the problems] The electrophotographic photoreceptor of the present invention, which was discovered as a means to achieve the above object of the present invention, contains silicone side chains and ethylene-based side chains at least in the layer furthest from the substrate. It is characterized in that it contains a comb-shaped graft polymer having a main chain of (hereinafter also simply referred to as a silicone-based comb-shaped graft polymer) and a polyarylate resin. That is, the present invention provides at least the following general formula () and general formula () in the layer farthest from the substrate.
Alternatively, it can be obtained by copolymerizing a modified silicone, which is a condensation reaction product of a silicone represented by the general formula () or at least a compound represented by the following general formula (), with a polymerizable ethylene compound. a comb-shaped graft polymer having a silicone-based side chain and an ethylene-based main chain;
The electrophotographic photoreceptor is characterized by containing a polyarylate resin. General formula () In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ represent an alkyl group or an aryl group which may have a substituent, and n represents an average degree of polymerization. General formula () In the formula, R ₆ and R ₇ represent an alkyl group or an aryl group which may have a substituent, and n represents an average degree of polymerization. General formula () In the formula, R ₈ , R ₉ and R ₁₀ are a hydrogen atom, an alkyl group or an aryl group which may have a substituent,
R ₁₁ is an alkyl group or an aryl group which may have a substituent, A is an arylene group which may have a substituent, X is a halogen atom or an alkoxy group which may have a substituent, and m is an integer from 1 to 3. The photosensitive layer has a photosensitive layer and a surface layer of a non-photosensitive layer as constituent components, and the layer that is farthest from the substrate is the non-photosensitive surface layer, and the photosensitive layer has a charge generation layer and a charge transport layer. The layer having a laminated structure and the farthest distance from the substrate is the photosensitive layer, and the layer having the photosensitive layer having a laminated structure of a charge generation layer and a charge transport layer as a component and the layer farthest from the substrate is the charge layer. The transport layer or the charge generation layer, and the content of the silicone comb-shaped graft polymer in the layer furthest from the substrate is 0.01 to 10% by weight.
can include the constituent requirements of being within the scope of. As is known in the art, an electrophotographic photoreceptor has a photosensitive layer on a substrate, and optionally a non-photosensitive subbing layer, an intermediate layer, a surface layer, etc., and the photosensitive layer includes There are those that have a single layer structure and those that have a laminated structure of a charge generation layer and a charge transport layer. The present invention can be applied to all of these known types of electrophotographic photoreceptors, and at least the layer furthest away from the substrate (hereinafter referred to as the surface layer of the present invention) may be, for example, the non-photosensitive surface layer, a single layer, etc. The silicone-based comb-shaped graft polymer and the polyarylate-based resin are contained in the photosensitive layer of the structure and the charge-generating layer or charge-transporting layer of the photosensitive layer of the laminated structure. The silicone-based comb-shaped graft polymer used in the present invention has the general formula () and the general formula (),
Or one obtained by copolymerizing a modified silicone, which is a condensation reaction product of general formula () or silicone represented by general formula (), and at least a compound represented by general formula (), and a compound having a polymerizable functional group. It has a structure in which silicone-containing side chain groups are bonded to the main chain in a branched manner. The compound represented by the above general formula will be explained in detail below. General formula () General formula () General formula () In the general formulas () and (),
R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ and R ₇ are methyl,
an alkyl group such as ethyl, propyl, butyl, or an aryl group such as phenyl, naphthyl,
It may have a substituent such as a halogen atom or a lower alkyl group. Preferred are methyl group and phenyl group. n indicates an average degree of polymerization, and is in the range of 1 to 1000, preferably in the range of 10 to 500. In the general formula (), R ₈ , R ₉ and R ₁₀ are hydrogen atoms, alkyl groups such as methyl, ethyl, propyl, butyl, or aryl groups such as phenyl and naphthyl, and these groups are halogen atoms, lower It may have a substituent such as an alkyl group. Preferably it is a hydrogen atom. R ₁₁ is an alkyl group such as methyl, ethyl, propyl, butyl or an aryl group such as phenyl or naphthyl, and may have a substituent such as a halogen atom. Preferred are methyl group and phenyl group. I is an arylene group such as phenylene, biphenylene, or naphthylene, and may have a substituent such as a halogen atom or a lower alkyl group. X is a halogen atom such as fluorine, chlorine, bromine, or iodine, preferably a chlorine atom, or an alkoxy group such as methoxy, ethoxy, propoxy, or butoxy, and may have a substituent such as a lower alkoxy group. good. Preferably a methoxy group,
They are an ethoxy group and a 2-methoxy-ethoxy group. m is an integer from 1 to 3. Next, typical examples of the compounds represented by the above general formula will be listed. Specific examples of compounds represented by general formula ()

[Table] ｜ ｜
CH ₃ CH ₃

[Table] ｜ ｜
_{C4H8ClCH3 _ _}

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【table】 Specific examples of compounds represented by general formula ()

[Table] ｜
C ₃ H ₇

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【table】 Specific examples of compounds represented by general formula ()

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[Table] The condensation reaction between general formula () and general formula (), or silicone represented by general formula () or general formula (), and at least a compound represented by general formula () is carried out according to ordinary organic chemical reaction procedures. The reaction molar ratio and reaction conditions were appropriately controlled in accordance with the description in JP-A-58-167606 and JP-A-59-126478, which disclose a method for synthesizing a comb-shaped graft polymer that proceeds extremely smoothly. By doing so, a stable modified silicone can be obtained. Compounds with polymerizable functional groups include macromonomers consisting of polymerizable monomers that do not have silicon atoms or relatively low molecular weight monomers with a molecular weight of about 1,000 to 10,000 that have a polymerizable functional group at the end. Examples include. Examples of polymerizable monomers include olefinic compounds such as low molecular weight linear unsaturated hydrocarbons such as ethylene, propylene and butylene, vinyl halides such as vinyl chloride and vinyl fluoride, and organic acids such as vinyl acetate. vinyl ester, styrene,
Styrene substitutes and other vinyl aromatic compounds such as vinylpyridine and vinylnaphthalene, acrylic acid, methacrylic acid and their esters, amides and derivatives of acrylic acid, including acrylonitrile, N-vinylcarbazole, N-vinylpyrrolidone and N-
N-vinyl compounds such as vinyl caprolactam,
Examples include vinyl silicon compounds such as vinyltriethoxysilane. Disubstituted ethylenes can also be used, examples of which include vinylidene fluoride, vinylidene chloride, and maleic anhydride, maleic acid and fumaric acid. In particular, acrylic esters, methacrylic esters, styrene, and the like are preferable because of their affinity with polyarylate resins. Further, the monomers can be used alone or in combination of two or more types. As a polymerization method for silicone-based comb-shaped graft polymers, radical polymerization and ionic polymerization such as solution polymerization, suspension polymerization, and bulk polymerization can be applied, but radical polymerization by solution polymerization is simple and preferred. The copolymerization ratio is preferably 5 to 90% by weight, more preferably 10 to 70% by weight as the silicone monomer content. The number average molecular weight of the obtained polymer is preferably 500 to 100,000, particularly preferably 1,000 to 50,000. Since the silicone-based comb-shaped graft polymer in the present invention has such a structure, it can be used as a binder resin for forming the surface layer in the present invention.
It has excellent compatibility with coating solutions containing polyarylate resins, and therefore the resulting coating film has good transparency and does not migrate or bleed onto the surface layer of the present invention. Furthermore, since the silicone-containing branch portion has excellent interfacial migration properties, surface modification can be achieved by adding a small amount. Furthermore, even if this additive is contained on the surface, there is no accumulation of residual charge due to repeated electrophotographic processes, and stable charging characteristics can be obtained. The amount of 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. If the amount added is less than 0.01, a sufficient surface modification effect will not be obtained, while if it exceeds 10%, the graft polymer will exist not only on the surface of the coating film but also in the bulk, so that the resin, which is the main component of the surface layer, will be present. or may cause whitening due to compatibility issues with photoconductive substances.
Residual charge buildup occurs during repeated electrophotographic processes. The polyarylate resin used in the present invention contains a linear polymer containing one or more repeating units represented by the following general formula (). General formula () In the formula, R ₁₂ and R ₁₃ are each a hydrogen atom,
It represents an alkyl group such as methyl, ethyl, propyl, butyl, or an aryl group such as phenyl or naphthyl, and may have a substituent such as a halogen atom or a lower alkyl group. Further, a cyclic structure may be formed together with the carbon atom bonded between R ₁₂ and R ₁₃ , and specific examples include a cyclohexyl ring and a lactone structure. X ₁ , X ₂ , X ₃ and X ₄ are each a hydrogen atom,
Indicates halogen atoms such as fluorine, chlorine, bromine, and iodine, alkyl groups such as methyl, ethyl, propyl, and butyl, alicyclic alkyl groups such as cyclohexyl, aryl groups such as phenyl and naphthyl, and alkoxy groups such as methoxy and ethoxy. . The above polyarylate resin can be obtained, for example, by a general polyarylate resin synthesis method such as a terephthalic acid chloride method using one or more diol compounds represented by the following general formula (). General formula () In the formula, R ₁₂ , R ₁₃ , X ₁ , X ₂ , X ₃ and X ₄ have the same meanings as in the general formula (). Next, typical specific examples of the compound represented by the general formula () are shown below.

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[Table] The present invention will be described in detail below, taking as an example the case where the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer, and the surface layer according to the present invention is the charge transport layer.
When producing the electrophotographic photoreceptor 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. A subbing layer (adhesive layer) having a barrier function and a subbing function can be provided on these substrates. The undercoat layer is formed to improve adhesion of the photosensitive layer, improve coating properties, protect the substrate, cover defects on the substrate, improve charge injection from the substrate, protect the photosensitive layer from electrical breakdown, etc. . The material for the undercoat layer is polyvinyl alcohol,
Known examples include poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, casein, polyamide, copolymerized nylon, glue, and gelatin. These are each dissolved in a suitable solvent and applied onto the substrate. The film thickness is
It is about 0.2 to 2μ. In the functionally separated photoreceptor, selenium, selenium-tellurium, pyrylium dyes, thiopyrylium dyes, phthalocyanine dyes, anthorone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, and azo pigments are used as charge-generating substances. Pigments, indigo pigments, quinacridone pigments, asymmetric quinocyanine, quinocyanine, or amorphous silicon described in JP-A-54-143645 can be used, and charge transport substances include pyrene, N-ethylcarbazole, and N-isopropyl. Carbazole, N-methyl-N-phenylhydrazino-3-methylidene-9
-Ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine, N,N-diphenylhydra Dino-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-ω-
Aldehyde-N,N-diphenylhydrazone, P
Hydrazones such as -diethylbenzaldehyde-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-methoxypyridyl
(2)]-3-(P-diethylaminostyryl)-5-
(P-diethylaminophenylpyrazoline, 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)
Pyrazolines such as pyrazoline and spiropyrazoline, 2-(P-diethylaminostyryl)-6-diethylaminobenzoxazole, 2-(P-diethylaminophenyl)-4-(P-dimethylaminophenyl)-5-(2-chlorophenyl) ) Oxazole compounds such as oxazole, 2-(P-
thiazole compounds such as (diethylaminostyryl)-6-diethylaminobenzthiazole, bis(4-diethylamino-2-methylphenyl)
Triarylmethane compounds such as phenylmethane, 1,1-bis(4-N,N-diethylamino-2-methylphenyl)heptane, 1,1,2,
2-tetrakis(4-N,N-dimethylamino-
Polyarylalkanes such as 2-methylphenyl)ethane and the like can be used. The charge generation layer contains the above charge generation substance in an amount of 0.3 to 4
It is formed by thoroughly dispersing, coating, and drying together with double the amount of binder resin and solvent using a homogenizer, ultrasonic wave, ball mill, vibrating ball mill, sand mill, attritor, roll mill, etc. Its thickness is about 0.1 to 1μ. The charge transport layer is formed by dissolving the polyarylate resin and silicone comb-shaped graft polymer, which are essential in the present invention, in a solvent together with a charge transport material as a binder, and coating the mixture on the charge generation layer. The mixing ratio of the charge transport material and the binder resin is 2:
The ratio is about 1 to 1:2. Examples of solvents used include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, and chlorinated hydrocarbons such as chlorobenzene, chloroform, and carbon tetrachloride. It will be done. When applying this solution, coating methods such as dip coating, spinner coating, bead coating, blade coating, and curtain coating can be used, and drying is carried out at 10 to 200°C, preferably 20 to 150°C.
The drying can be carried out at a temperature in the range of 0.degree. C. for 5 minutes to 5 hours, preferably 10 minutes to 2 hours under blow drying or stationary drying. The thickness of the generated charge transport layer is 5 to 20μ
That's about it. Further, the charge transport layer can contain various additives. Additives include diphenyl, diphenyl chloride, O-terphenyl, P-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin, dilaurylthiopropionate, 3,5- Examples include dinitrosalicylic acid and various fluorocarbons. On the other hand, in a functionally separated photoreceptor having a charge generation layer as a surface layer, the polyarylate resin of the present invention and a silicone comb-shaped graft polymer can be used as a binder for a charge generation substance. Furthermore, even in a single-layer type photoreceptor in which the photoreceptor layer is a surface layer defined in the present invention, a polyarylate resin and a silicone-based comb-shaped graft polymer can be used as a binder in the photoreceptor layer. When a non-photosensitive surface is provided as a protective layer, for example, the polyarylate resin and silicone comb-shaped graft polymer can be used as protective film forming materials. Hereinafter, the present invention will be explained according to examples. The silicone-based comb-shaped graft polymers (samples (a) to (o)) used in the examples are those disclosed in JP-A-58-167606 and JP-A-59-126478, which disclose a method for synthesizing comb-shaped graft polymers. It was synthesized according to the polymerization method described in the publication, and its composition is listed below.

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[Table] The structures of the synthesized silicone-based comb-shaped graft polymers are shown below as representative examples for sample (a) and sample (h). Sample (a) n: average 30, p ₁ , q ₁ ; positive integer A ₁ /B ₁ ; 30/70 (weight ratio) Sample (h) n: average 30, p ₂ , q ₂ ; positive integer A ₂ /B ₂ ; 30/70 (weight ratio) The polyarylate resin is produced by the reaction between the compound represented by the above general formula () and terephthalic acid chloride. synthesized by Specifically, 1.0 mol of bisphenols is dissolved in 1 mol of sodium hydroxide aqueous solution, a surfactant is added, and while stirring vigorously, a solution of 1.0 mol of terephthalic acid chloride dissolved in chloroform is added. After continued stirring, the emulsion obtained is poured into acetone to precipitate a polymer, which is thoroughly washed with water, filtered, and dried by heating to obtain a white polymer. Example 1 10 parts (parts by weight, the same applies hereinafter) of New Zealand-produced lacquer casein were weighed out, dispersed in 90 parts of water, and then dissolved in 1 part of ammonia water.
Separately, 3 parts of hydroxypropyl methylcellulose resin (trade name: Metrose 60SH50, manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in 20 parts of water, and the two were then mixed to prepare a coating solution for the undercoat layer. Apply this coating liquid to 80φ×300mm.
80% by dipping method onto an aluminum cylinder.
It was dried at ℃ for 10 minutes to form a 2μ thick subbing layer.
Next, 10 parts of a disazo pigment with the following structure, Cellulose acetate butyrate resin (product name CAB-381,
(manufactured by Eastman Chemical Co., Ltd.) 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, apply it on the undercoat layer by dip coating, heat dry at 100°C for 10 minutes,
A charge generation layer was provided with a coating weight of g/m ² . Next, 10 parts of a hydrazone compound with the following structure, 10 parts of a polyarylate resin synthesized according to the synthesis method of the polyarylate resin described above using the compound of the specific example (112) of the general formula () was dissolved in 100 parts of dichloromethane. Add the sample (a) to this solution.
0.2 parts of silicone-based comb-shaped graft polymer was added as solid content. This solution was applied onto 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 is designated as sample 1. Electrophotographic photoreceptors similarly prepared using the silicone comb-shaped graft polymers of Samples (b) to (o) are designated as Samples 2 to 15. For comparison, a sample 1 without the silicone comb-shaped graft polymer was prepared in the same manner as above, and this was designated as comparative sample 1. For these samples, −5.5 kV, corona charging,
Durability was evaluated on 30,000 sheets 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 below. Evaluation environment: 32.5°C, RH 90% For samples 1 to 15, stable high-quality images were obtained up to 30,000 sheets. In Comparative Sample 1, image deletion occurred after about 500 copies were made. Example 2 10 parts of the hydrazone compound used in Example 1 and 10 parts of a polyarylate resin synthesized using the compound of specific example (117) of general formula () were dissolved in 80 parts of monochlorobenzene. To this liquid, 0.4 parts of silicone-based comb-shaped graft polymer of sample (h) was added as solid content. This solution was coated on a substrate coated up to the charge generation layer prepared in the same manner as in Example 1, and
A charge transport layer with a thickness of 16 μm was formed by drying with hot air for an hour. This is designated as sample 16. For comparison, a product without the silicone comb-shaped graft polymer was prepared in the same manner as above.
This will be referred to as comparative sample 2. The durability of these samples was evaluated under the same conditions as in Example 1. The results are shown below. sample
With the 16, stable high-quality images were obtained up to 20,000 images. In comparative sample 2, image deletion occurred after about 500 sheets. Example 3 An aluminum cylinder of 80φ x 300mm was used as a base, and polyamide resin (trade name Amiran) was applied to this
A 5% methanol solution of CN-8000 (manufactured by Toray Industries, Inc.) was applied by dipping to form a 1 μm thick subbing layer. Next, 12 parts of a pyrazoline compound with the following structure, 10 parts of the polyarylate resin synthesized in Example 2 was dissolved in 60 parts of monochlorobenzene. This solution was dip coated onto the undercoat layer and dried at 100° C. for 1 hour to form a charge transport layer with a thickness of 14 μm. Next, the same bisazo pigment used in Example 1 was used.
10 parts of the polyarylate resin synthesized in Example 1
It was added to 100 parts of a 10% by weight dioxane solution and dispersed for 20 hours using a sand mill device using glass beads. One part of the silicone comb-shaped graft polymer of sample (c) was added as a solid content to this dispersion. Apply this solution onto the charge transport layer and heat it at 100℃.
It was dried for 20 minutes to form a 2μ thick charge generation layer.
This is designated as sample 17. For comparison, a sample without the silicone comb-shaped graft polymer was prepared in the same manner as above, and this was designated as Comparative Sample 3. The sample thus obtained was charged with +5.6kV corona.
It was installed in an electrophotographic copying machine that has image exposure, dry toner development, toner transfer to plain paper, and cleaning steps using a urethane rubber blade, and the durability was evaluated on 3000 copies under an environment of 32.5°C and RH 90%. For sample 17, high-quality images were obtained up to 3000 copies. In Comparative Sample 3, the toner was fused onto the surface layer after 300 copies, and many black spots appeared on the image. Example 4 10 parts of the same hydrazone compound used in Example 1 and 10 parts of the polyarylate resin synthesized in Example 2 were dissolved in 60 parts of monochlorobenzene. This solution was applied by dip coating onto the undercoat layer formed in the same manner as in Example 3, and dried at 100°C for 1 hour.
A charge transport layer of 15μ was formed. Next, 10 parts of the same bisazo pigment used in Example 3 was added to 100 parts of a 10% by weight monochlorobenzene solution of the polyarylate resin synthesized in Example 2.
Dispersion was carried out for 20 hours using a sand mill device using glass beads. One part of the silicone comb-shaped graft polymer of sample (j) was added as a solid content to this dispersion.
This solution is pushed up and applied onto the charge transport layer.
It was dried at 100° C. for 20 minutes to form a charge generation layer with a thickness of 2.5 μm. This is designated as sample 18. For comparison, a sample without the silicone comb-shaped graft polymer was prepared in the same manner as above.
This will be referred to as comparative sample 4. The durability of these samples was evaluated under the same conditions as in Example 3. For sample 16, high-quality images were obtained up to 2000 copies. In comparative sample 4, image deletion occurred after about 800 copies were made. Example 5 Two parts of the polyarylate resin synthesized in Example 1 were dissolved in 100 parts of dichloromethane. To this solution, 0.15 of the silicone-based comb-shaped graft polymer of sample (e) was added in terms of solid content. This solution was added to Sample 6 of Example 1.
It was spray coated onto an electrophotographic photoreceptor prepared in the same manner as above and dried at 100°C for 5 minutes to form a 0.5μ thick protective layer. This is designated as sample 19. Similarly, 2 parts of the polyarylate resin synthesized in Example 2 was dissolved in 100 parts of monochlorobenzene, and further,
A solid content of 0.5 part of the silicone comb-shaped graft polymer of sample (i) was added. This solution was spray-coated onto an electrophotographic photoreceptor prepared in the same manner as Comparative Sample 2 of Example 2, and dried at 100°C for 5 minutes to give a 0.4μ
A protective layer was formed. This is designated as sample 20. These samples were treated under the same conditions as in Example 1.
Durability evaluation was conducted on 5000 sheets. High-quality images were obtained for both samples 19 and 20 up to 5,000 copies. Comparative example: Instead of silicone-based comb-shaped graft polymer,
Comparative sample 5 is a sample prepared in the same manner as in Example 1, except that 1 part of silicone oil (trade name KF96, manufactured by Shin-Etsu Silicone Co., Ltd.) was used as a solid content. Similarly, a sample prepared in the same manner as in Example 4, except for using 1 part of the above silicone oil, was designated as Comparative Sample 6. The durability of these samples was evaluated under the same conditions as in Example 3, but the background fog was significant, and the degree of fog increased with repeated copying. When Comparative Samples 5 and 6 were observed one month after their preparation, it was found that the silicone oil had migrated to the surface layer and stood out in the form of a stain. On the other hand, samples 1 to 20 to which silicone-based comb-shaped graft polymers were added showed no such change over time, and exhibited the same appearance and characteristics as the initial stage. Example 6 (Measurement of potential characteristics) Next, regarding samples 1, 16 and comparative sample 5, -
The sample was attached to an electrophotographic copying machine equipped with a 5.5 kV corona charger, and an empty charging durability test was carried out on 30,000 sheets at room temperature and humidity, and fluctuations in V _D potential and V _L exposed to light at 7.5 lux for seconds were measured. The results are shown below. Table 2 Sample Initial After 30,000 sheets V _D (-V) V _L (-V) V _D (
-V) V _L (-V) 1 705 190 680 260 16 700 185 665 250 Comparative sample 5 725 200 640 350 As shown in the table above, the V _L variation after 30,000 sheets of the sample to which silicone oil was added was very large. big.
In contrast, it can be seen that the photoreceptor of the present invention has an extremely stable potential during durability. Example 7 (Measurement of potential characteristics) Next, regarding sample 18 and comparative sample 6, +
An electrophotographic copying machine equipped with a 5.5kV corona charger was used to carry out an empty charging durability test of 3,000 sheets at room temperature and humidity, and the V _D potential and 7.5 Lux. Fluctuations in the V _L potential after second exposure were measured. The results are shown below. Table 3 Initial After 3000 sheets of durability V _D (V) V _L (V) V _D (V) V _L (V) Sample 18 665 155 615 225 Comparative sample 6 680 170 625 310 Apply silicone oil as shown in the table above. The V fluctuation of the added sample after running 3000 sheets was extremely large. In contrast, it can be seen that the photoreceptor of the present invention has an extremely stable potential during durability. Example 8 (Friction force test) Next, the friction force between the urethane blade and the surface layer was measured for the sample and the comparative sample. The results are shown below. (Frictional force is expressed as a relative value, with the frictional force of comparative sample 2 as reference value 1.) Table 4 Sample Frictional force Sample Frictional force 1 0.22 2 0.31 3 0.34 4 0.40 5 0.23 6 0.22 7 0.33 8 0.24 9 0.33 10 0.28 11 0.31 12 0.28 13 0.24 14 0.26 15 0.24 16 0.17 17 0.16 18 0.12 19 0.27 20 0.26 Comparison sample Friction force Comparison sample Friction force 1 0.99 2 1.00 3 0.95 4 0.94 5 0.15 6 0.14 Silicone comb as shown in the table above. The photoreceptor of the present invention to which the type graft polymer was added and the comparative sample to which silicone oil was added had significantly reduced frictional force compared to the sample to which no additive was added. However, the comparative sample to which silicone oil was added had poor storage stability and potential stability during durability as described above. Example 9 In place of the polyarylate resin used in Example 1, specific examples of general formula () (116), (120),
Although each polyarylate resin synthesized using compounds such as (121), (128), (131), (133), and (13) was used, the results were similar to those of the polyarylate resin of Example 1. was gotten. By adding the silicone-based comb-shaped graft polymer in this manner, the frictional force of the surface layer is reduced, and the cleaning performance is improved and it is difficult for deposits such as toner and paper dust to stick to the surface layer. In particular, the combination with polyarylate resin has excellent durability, little increase in residual potential, and exhibits stable characteristics over a long period of time. [Effects 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 charge in repeated electrophotographic processes.

Claims (1)

[Claims] 1 At least in the layer farthest from the substrate, silicone represented by the following general formula () and general formula (), or the following general formula () or general formula (), and at least a silicone represented by the following general formula (). A comb-shaped graft polymer having a silicone side chain and an ethylene main chain obtained by copolymerizing a modified silicone, which is a condensation reaction product with the compound shown, and a polymerizable ethylene compound, and a polyarylate resin. An electrophotographic photoreceptor comprising: General formula () In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ represent an alkyl group or an aryl group which may have a substituent, and n represents an average degree of polymerization. General formula () In the formula, R ₆ and R ₇ represent an alkyl group or an aryl group which may have a substituent, and n represents an average degree of polymerization. General formula () In the formula, R ₈ , R ₉ and R ₁₀ are a hydrogen atom, a halogen atom, an alkyl group or an aryl group which may have a substituent, R ₁₁ is an alkyl group or an aryl group which may have a substituent, A is an arylene group which may have a substituent, X is a halogen atom or an alkoxy group which may have a substituent, and m is 1 to 3.
indicates an integer. 2. The electrophotographic photoreceptor according to claim 1, which comprises a photosensitive layer and a non-photosensitive surface layer as constituent components, and the layer that is furthest away from the substrate is the non-photosensitive surface layer. 3. The electrophotographic photoreceptor according to claim 2, wherein the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer. 4. The electrophotographic photoreceptor according to claim 1, wherein the layer furthest away from the substrate is a photosensitive layer. 5. The electrophotographic photoreceptor according to claim 1, which comprises a photosensitive layer having a laminated structure of a charge generation layer and a charge transport layer as a component, and the layer farthest from the substrate is the charge transport layer. 6. The electrophotographic photoreceptor according to claim 1, which comprises as a component a photosensitive layer having a laminated structure of a charge generation layer and a charge transport layer, and the charge generation layer is the layer furthest away from the substrate. 7. Claims 1 to 6, wherein the content of the silicone comb-shaped graft polymer in the layer furthest from the substrate is within the range of 0.01 to 10% by weight.
The electrophotographic photoreceptor according to item 1.