JP2002214807A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor superior in electrical characteristics and surface lubricity. SOLUTION: In the electrophotographic photoreceptor having at least a photosensitive layer on an electrically conductive substrate, a polyester resin having a polysiloxane structure is contained in the outermost layer of the photoreceptor and the polysiloxane content of the polyester resin is 0.1 to <5 wt.% of all the binder resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member using a polyester resin as a binder resin. More specifically, the present invention relates to an electrophotographic photosensitive member containing a specific amount of polysiloxane in a binder resin and having excellent mechanical properties.

[0002]

2. Description of the Related Art In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers because of its immediacy and high-quality images. Photoconductors, which are the core of electrophotographic technology, have been formed from conventional inorganic photoconductors such as selenium, arsenic-selenium alloy, cadmium sulfide, and zinc oxide as photoconductive materials. A photoreceptor using an organic photoconductive material having advantages such as easy and easy production has been developed. As the organic photoconductor, a so-called dispersion type photoconductor in which photoconductive fine powder is dispersed in a binder resin, and a stacked type photoconductor in which a charge generation layer and a charge transfer layer are laminated are known. The laminated photoreceptor can be obtained by combining a highly efficient charge generating substance and a charge transfer substance to obtain a highly sensitive photoreceptor, a wide material selection range and a highly safe photoreceptor, and coating. Since it is highly productive and relatively advantageous in terms of cost, it is highly likely to become the mainstream of the photoreceptor and has been developed and put into practical use. The electrophotographic photoreceptor is repeatedly used in an electrophotographic process, that is, in a cycle of charging, exposure, development, transfer, cleaning, charge removal, and the like. Such deterioration includes, for example, strongly oxidizing ozone and NOx generated from a corona charger commonly used as a charger, causing chemical damage to the photosensitive layer, and a carrier (current) generated by image exposure. Is chemically and electrically deteriorated due to, for example, the flow of the compound in the photosensitive layer, the charge removal light, and the decomposition of the photosensitive layer composition due to external light. Further, other deteriorations include mechanical deterioration such as abrasion and scratches on the surface of the photosensitive layer due to contact with a cleaning blade, a magnetic brush or the like, contact with a developer or paper, and peeling of a film. In particular, such damages on the surface of the photosensitive layer tend to appear on the copy image and directly impair the image quality, which is a major factor limiting the life of the photosensitive member. That is, in order to develop a photoreceptor having a long life, it is an essential condition to increase the electrical and chemical durability as well as the mechanical strength. Generally, in the case of a laminated photoreceptor, it is the charge transfer layer that receives such a load. The charge transfer layer usually consists of a binder resin and a charge transfer material,
Although it is the binder resin that substantially determines the strength, the doping amount of the charge transfer material is so large that it has not yet achieved sufficient mechanical strength. Also, with the increasing demand for high-speed printing, materials for higher-speed electrophotographic processes are required. In this case, the photoreceptor must have high sensitivity and long life, and also have good responsiveness because the time from exposure to development is short. It is known that the responsivity of the photoreceptor is governed by the charge transfer layer, especially the charge transfer material, but varies greatly depending on the binder resin. As the binder resin of the conventional charge transfer layer, polymethyl methacrylate, polystyrene, vinyl polymers such as polyvinyl chloride, and copolymers thereof, polycarbonate, polyester, polysulfone,
Thermoplastic resins such as phenoxy, epoxy and silicone resins and various thermosetting resins have been used. Among many binder resins, polycarbonate resins have relatively excellent performance, and various polycarbonate resins have been developed and put to practical use. For example, Japanese Patent Application Laid-Open No. Sho 50-98332 discloses bisphenol P type polycarbonate, Japanese Patent Application Laid-Open No. Sho 59-71057 discloses a bisphenol Z type polycarbonate, and Japanese Patent Application Laid-Open No. Sho 59-184251 discloses bisphenol P and bisphenol A. JP-A-5-21478 discloses a polycarbonate copolymer having a bis (4-hydroxyphenyl) ketone type structure as a binder resin. However, conventional organic photoconductors have drawbacks such as surface wear and surface damage due to practical loads such as development with toner, friction with paper, and friction with a cleaning member (blade). At present, the printing performance is limited in practice. On the other hand, Japanese Patent Application Laid-Open No. 56-135844 discloses a product name "U
The technology of an electrophotographic photoreceptor using a polyarylate (aromatic polyester) resin commercially available as a “polymer” as a binder is disclosed, and among them, it is shown that the sensitivity is particularly excellent as compared with polycarbonate. ing. Japanese Patent Laid-Open Publication No. Hei 3-6567 discloses an electrophotographic photoreceptor characterized by containing a polyarylate (aromatic polyester) copolymer having a structure using tetramethylbisphenol F and bisphenol A as a bisphenol component. ing. However, these aromatic polyesters have disadvantages in that the solubility of the photosensitive layer in the solvent for application and the stability of the solution are poor, and when these are used as a binder for the photosensitive layer, the electrical properties are deteriorated.
In recent years, there has been a demand for a photoreceptor having better surface slipperiness with improvement in image quality. In order to improve the surface slipperiness, an electrophotographic photosensitive member using a polyester obtained by copolymerizing polysiloxane as a binder resin for a photosensitive layer has been proposed. For example, a resin obtained by block copolymerizing an aromatic polyester with a polysiloxane is used as a binder (Japanese Patent Laid-Open No. 3-185451).
And JP-A-10-20534) and use of a polyester resin containing a polysiloxane constituent unit (JP-A-8-234468), all of which have improved surface slipperiness. However, at present, there are problems such as adverse effects on electrical characteristics.

[0003]

When the currently used polycarbonate resin is used in an electrophotographic process, it often remains unsatisfactory in abrasion resistance, scratch resistance, surface slippage, and the like. In the case of the commercially available polyarylate resin “U-Polymer”, although the abrasion resistance and the sensitivity are slightly improved, the stability of the coating solution is poor, so that the coating cannot be produced or the slip property is poor. Was. Also, Japanese Patent Laid-Open No. 3-65
In the case of using a polyarylate (aromatic polyester) copolymer having a structure using tetramethylbisphenol F and bisphenol A as the bisphenol component disclosed in Japanese Patent No. 67, the abrasion resistance is lower than that of a conventional polycarbonate. Although an improvement is seen, no superiority is recognized in comparison with polycarbonate in terms of slipperiness, and performance is significantly inferior to polycarbonate in terms of electrical characteristics, particularly sensitivity and responsiveness.

[0004] Therefore, at present, there is a demand for a binder resin which is excellent in abrasion resistance and slipperiness while maintaining good electrical characteristics such as responsiveness.

[0005]

The inventors of the present invention have studied the binder resin used in the photosensitive layer in detail, and found that the polyester resin having a polysiloxane structure has a specific polysiloxane content in the total binder resin. By using so as to have a very excellent slipperiness, solubility in non-halogen solvents / stability of the coating solution is improved,
In addition, they have found that they have excellent electrical characteristics, particularly excellent responsiveness, and have reached the present invention. Conventional polyester resins are inferior to polycarbonate resins in terms of electrical characteristics, and therefore have practical performance except that a small amount of a polyester resin is blended with the polycarbonate resin as exemplified in JP-A-7-128884. Could not be obtained. However, since the polyester resin of the present invention has significantly improved electrical properties and excellent mechanical strength, a practical electrophotographic photoreceptor having excellent slipperiness can be obtained by using the polyester resin of the present invention. Was completed.

That is, the gist of the present invention is to provide an electrophotographic photosensitive member having at least a photosensitive layer on a conductive substrate, wherein the outermost layer of the electrophotographic photosensitive member contains a polyester resin having a polysiloxane structure, An electrophotographic photoreceptor characterized in that the siloxane content is 0.1% by weight or more and less than 5% by weight in all binder resins in the outermost layer.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (I) Polyester Resin Having Polysiloxane Structure In the present invention, the polyester resin contained in the outermost layer of the electrophotographic photosensitive member contains a polysiloxane structure. The polysiloxane structure is specifically represented by, for example, the following general formula (1).

[0008]

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In the general formula (1), n represents an integer of 1 to 500, preferably 10 to 200, more preferably 2
It is 0-100. If n is too small, the slipperiness improving effect tends to decrease. On the other hand, if n is too large, the transparency of the resin or solution is lost, and when used as a binder for an electrophotographic photoreceptor, the electrical properties may be adversely affected.

In the general formula (1), R ¹ and R ² each independently represent an alkyl group which may have a substituent or an aromatic group which may have a substituent, for example, a methyl group, Ethyl group, propyl group, isopropyl group, butyl group, tert-butyl group, isobutyl group, or a linear or branched alkyl group having 5 to 30 carbon atoms, cyclohexyl group, chloromethyl group, fluorine-substituted alkyl group, benzyl Examples of the alkyl group may include a phenyl group, a chlorophenyl group, a fluorophenyl group, and a naphthyl group. Preferably, a methyl group, a fluoroalkyl group and a phenyl group are mentioned.

The structure of the polyester portion of the polyester resin containing the polysiloxane of the present invention is represented, for example, by the following formula (2).

[0012]

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In the general formula (2), R ^{6 to} R ¹³ each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, an alkoxyl group, a halogen atom, an optionally substituted aromatic group. X is a single bond,
It represents any one of an alkylene group, a cycloalkylene group, an oxygen atom and a sulfur atom, and Y represents one or more divalent organic groups. Specifically, R ^{6 to} R ¹³ each independently represent, for example, a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, an isobutyl group, a cyclohexyl group, a chloromethyl group, Alkyl group,
A benzyl group or the like may be mentioned as an alkyl group having 1 to 20 carbon atoms which may be substituted, and an aromatic group which may be substituted may be a phenyl group, a chlorophenyl group, a fluorophenyl group or the like. Preferably, they are a hydrogen atom and a methyl group. X, for example, a single _{bond, -CH 2 -, - (CH} 2)
₂ -,-(CH ₂ ) _3-

[0014]

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And the like. Preferably -CH ₂ -. Y is 1,4-phenylene group, 1,3-
Phenylene group, 1,2-phenylene group, naphthylene group,
Biphenylene _{group, -CH 2 -, - (CH} 2) 2 -, - (C
_{H 2) 3 -, - (} CH 2) 4 -, - (CH 2) 5 -, - (CH
_{2) 6 -, - (CH} 2) 7 -, - (CH 2) 8 -, - CH = C
H- and the like. The polyester resin of the present invention can be produced from a dicarboxylic acid and a diol, and as the aromatic diol, hydroquinone, resorcinol,
1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,
6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 1,5-
Dihydroxynaphthalene, bis- (4-hydroxyphenyl) methane (BPF), bis- (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxy Phenyl) ethane (BPE), 1,1-bis- (4
-Hydroxyphenyl) propane, 2,2-bis- (4
-Hydroxyphenyl) propane (BPA), 2,2-
Bis- (4-hydroxyphenyl) butane, 2,2-bis- (4-hydroxyphenyl) pentane, 2,2-bis- (4-hydroxyphenyl) -3-methylbutane,
2,2-bis- (4-hydroxyphenyl) hexane,
2,2-bis- (4-hydroxyphenyl) -4-methylpentane, 1,1-bis- (4-hydroxyphenyl) cyclopentane, 1,1-bis- (4-hydroxyphenyl) cyclohexane (BPZ), Bis- (3-phenyl-4-hydroxyphenyl) methane, 1,1-bis- (3-phenyl-4-hydroxyphenyl) ethane, 1,1-bis- (3-phenyl-4-hydroxyphenyl) propane, 2,2-bis- (3-phenyl-4
-Hydroxyphenyl) propane (BPQ), bis-
(4-Hydroxy-3-methylphenyl) methane (Co
f), 1,1-bis- (4-hydroxy-3-methylphenyl) ethane (Ce), 2,2-bis- (4-hydroxy-3-methylphenyl) propane (BPC), 2,
2-bis- (4-hydroxy-3-ethylphenyl) propane, 2,2-bis- (4-hydroxy-3-isopropylphenyl) propane, 2,2-bis- (4-hydroxy-3-sec-butyl) Phenyl) propane, 1,
1-bis- (4-hydroxy-3,5-dimethylphenyl) ethane (Xe), 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane (Tma), bis- (4-hydroxy -3,6-dimethylphenyl) methane (Xf), 1,1-bis- (4-hydroxy-3,
6-dimethylphenyl) ethane, bis- (4-hydroxyphenyl) phenylmethane, 1,1-bis- (4-hydroxyphenyl) -1-phenylethane (BPP),
1,1-bis- (4-hydroxyphenyl) -1-phenylpropane, bis- (4-hydroxyphenyl) diphenylmethane, bis- (4-hydroxyphenyl) dibenzylmethane, 4,4′-dihydroxydiphenyl ether (BPO) 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, phenolphthalein, 4,4 '-[1,4-phenylenebis (1-methylvinylidene)] bisphenol, 4,4'-[ 1,4-phenylenebis (1-methylvinylidene)] bis [2-methylphenol] and the like. Among these, a preferred example is bis- (4
-Hydroxyphenyl) methane (BPF), 1,1-bis- (4-hydroxyphenyl) ethane (BPE),
2,2-bis- (4-hydroxyphenyl) propane (BPA), 2,2-bis- (3-phenyl-4-hydroxyphenyl) propane (BPQ), bis- (4-hydroxy-3-methylphenyl) Methane (Cof),
1,1-bis- (4-hydroxyphenyl) cyclohexane (BPZ), 1,1-bis- (4-hydroxy-3
-Methylphenyl) ethane (Ce), 2,2-bis-
(4-hydroxy-3-methylphenyl) propane (B
PC) bis- (4-hydroxy-3,5-dimethylphenyl) methane (Tmf), 1,1-bis- (4-hydroxy-3,5-dimethylphenyl) ethane (Xe),
2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane (Tma), bis- (4-hydroxy-3,6-dimethylphenyl) methane (Xf), 1,1
-Bis- (4-hydroxyphenyl) -1-phenylethane (BPP). Examples of the aliphatic dihydroxy compound include ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-pentanediol, pentamethylenediol, 2,4-pentanediol, 1,5-hexanediol, hexamethylene glycol, , 5-heptanediol, heptamethylenediol, octamethylenediol, 1,9-nonanediol, 1,10-decamethylene glycol, 1,6-cyclohexanediol, etc., preferably ethylene glycol, propylene glycol, , 4-butanediol. The content of the polysiloxane contained in the polyester resin is 0.1% by weight or more and less than 5% by weight, preferably 0.2 to 3% by weight, based on the total amount of all the binder resins contained in the outermost layer. Preferably it is 0.5 to 2.5% by weight. If the content of polysiloxane is too small, the effect of improving slipperiness cannot be sufficiently obtained,
On the other hand, if the amount is too large, the abrasion resistance, optical properties and electrical properties are adversely affected. The viscosity average molecular weight of the polyester resin of the present invention is preferably 20,000 to 200,000, and more preferably 2.5 to 200,000.
10,000 to 100,000. If the viscosity average molecular weight is too small, the abrasion resistance will be deteriorated, and if it is too large, the viscosity of the coating solution will be too high and the productivity will tend to be reduced. As a method for producing the polyester resin used in the present invention, known polymerization methods can be used, and examples include an interfacial polymerization method, a melt polymerization method, and a solution polymerization method. For example, in the case of production by an interfacial polymerization method, a solution obtained by dissolving one or more difunctional phenol components or bisphenol components in an aqueous alkaline solution and a halogenated hydrocarbon containing one or more aromatic dicarboxylic acid chloride components are dissolved. Mix with the solution. In this case, a quaternary ammonium salt or a quaternary phosphonium salt can be used as a catalyst. The polymerization temperature is usually in the range of 0 to 40 ° C, and the polymerization time is preferably in the range of 2 to 12 hours from the viewpoint of productivity. After completion of the polymerization, the aqueous phase and the organic phase are separated, and the polymer dissolved in the organic phase is washed and recovered by a known method to obtain a target resin. Examples of the alkali component used here include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide. The amount of the alkali used is preferably in the range of 1 to 3 equivalents of the phenolic hydroxyl group contained in the reaction system. The halogenated hydrocarbon used herein includes dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, dichlorobenzene and the like. Examples of the quaternary ammonium salt or quaternary phosphonium salt used as a catalyst include salts of tertiary alkylamines such as tributylamine and trioctylamine with hydrochloric acid, bromic acid and iodic acid, benzyltriethylammonium chloride, benzyltrimethylammonium chloride, Examples include benzyltributylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, trioctylmethylammonium chloride, tetrabutylphosphonium bromide, triethyloctadecylphosphonium bromide, N-laurylpyridinium chloride, laurylpicolinium chloride, and the like. Specific examples of the bifunctional phenol component or bisphenol component include the above-mentioned aromatic diols.
It is also possible to use a mixture of species or more. As a method for producing a polyester having a polysiloxane structure of the present invention, for example, a method of coexisting a polysiloxane having a dihydric phenol structure represented by the following structural formulas (3-1) to (3-3) or an alkali salt thereof at the time of polymerization: Can be applied.

[0016]

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R in the structural formulas (3-1) to (3-3)
₁₄ to R ₃₀ represents an alkyl group or a substituent an aromatic group optionally having a, preferably methyl group, an ethyl group, a phenyl group. Rf in the structural formula (3-2) is an optionally substituted alkyl group, preferably a halogenated alkyl group;
More preferably, it is a fluorine-substituted alkyl group. Z is
Represents a single bond, an alkylene group, a cycloalkylene group, an oxygen atom, or a sulfur atom, for example, a single bond, -C
_{H 2 -, - (CH 2} ) 2 -, - (CH 2) 3 -

[0018]

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And the like. Preferably,

[0020]

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And a single bond. As a method for producing a polyester resin having a polysiloxane structure, a method of charging a polysiloxane component containing a bifunctional phenol into a reaction system at the time of polymerization can be used. The method of charging the polysiloxane component containing the bifunctional phenol may be such that the polysiloxane containing the bifunctional phenol is dissolved in an organic solvent such as methylene chloride and charged, or dissolved or suspended in an aqueous alkali solution such as Na or K. You may be charged.
The charging time of the polysiloxane containing the bifunctional phenol may be before the polymerization reaction, during the polymerization reaction, or at the end of the polymerization reaction. Other methods for producing the polysiloxane polyester copolymer include a method of reacting a halogenated polysiloxane at both ends, a method of reacting a polysiloxane having an amino group at both ends, and a method of reacting a carbon-carbon of a polyester having a carbon-carbon double bond in a molecule. It can also be produced by a hydrosilylation reaction of a polysiloxane having a Si—H structure at one end to a double bond.

In the polymerization, phenol, o, m, p-cresol, o, m, p-ethylphenol, o, m, p-propylphenol,
alkylphenols such as o, m, p-tert-butylphenol, pentylphenol, hexylphenol, octylphenol, nonylphenol, o, m, p-
Monofunctional acids such as monofunctional phenols such as phenylphenol, acetic acid chloride, butyric acid chloride, octylic acid chloride, benzoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, benzenephosphonyl chloride, and substituted products thereof A halide may be present.

The method for purifying the resin after polymerization is to prepare a solution of the resin in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide,
After washing with an aqueous acid solution such as hydrochloric acid, nitric acid, phosphoric acid, water, etc.,
Liquid separation may be performed by stationary separation, centrifugation, or the like. Further, the resulting resin solution is purified by a method of precipitating in a solvent in which the resin is insoluble, a method of dispersing the resin solution in warm water to distill off the solvent, or a method of flowing the resin solution through an adsorption column or the like. Is also good.

The purified resin is precipitated in water, alcohol or other organic solvent in which the resin is insoluble, or the resin solution is distilled off in hot water or a dispersion medium in which the resin is insoluble, or heated, reduced in pressure, etc. May be taken out by distilling off the solvent, or when taken out in the form of slurry, a centrifugal separator,
Solids can also be removed by filtration. The obtained resin is usually dried at a temperature not higher than the decomposition temperature of the resin, preferably at a temperature not lower than 20 ° C. and not higher than the melting temperature of the resin under reduced pressure. The drying time is longer than the time required for the purity of impurities such as residual solvent to be below a certain level.
The drying is performed for at least 0 ppm, preferably at most 300 ppm, more preferably at least 100 ppm.

The resin having a polyester structure of the present invention can be mixed with other resins and used for an electrophotographic photosensitive member or the like. Other resins mixed here include polymethyl methacrylate, polystyrene, vinyl polymers such as polyvinyl chloride and copolymers thereof, polycarbonate, polyester, polysulfone, phenoxy,
Examples include thermoplastic resins such as epoxy and silicone resins, and various thermosetting resins. Among these resins, polycarbonate resins are preferred.
When used as a binder resin for the photosensitive layer of the electrophotographic photoreceptor, the amount of the other resin that may be used in combination with the polyester resin of the present invention is usually 80% by weight or less, preferably 50% by weight or less in all binder resins. It is more preferably at most 30% by weight, most preferably at most 10% by weight.

The polyester resin having a polysiloxane structure used in the present invention may be a copolymer with another resin as long as the physical properties of the present resin are not substantially impaired. The copolymerization type may be a block, graft or multi-block copolymer. Examples of other resin structures to be copolymerized here include various resins such as polycarbonate, polyarylate, polysulfone, polyether, polyketone, polyamide, polysiloxane, polyimide, polystyrene, and polyolefin.

In the present invention, when a polyester resin having a polysiloxane structure is used as a binder resin for a photosensitive layer described later, when a polycarbonate resin is further mixed and used, the electrical characteristics are further improved, and the mechanical properties derived from the polyester resin are improved. It is preferable because both characteristics and electrical characteristics derived from the polycarbonate resin can be provided. Known polycarbonate resins can be used, and examples thereof include those having a structural unit derived from the following bifunctional phenol. Bifunctional phenol compounds include bis- (4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 1,1-bis- (4-hydroxyphenyl) propane, 2,2- Bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) butane, 2,2-bis- (4-hydroxyphenyl) pentane, 2,2-bis- (4-hydroxyphenyl) -3-methylbutane, 2,2-bis- (4-hydroxyphenyl) hexane, 2,2-bis- (4-hydroxyphenyl) -4-methylpentane, 1,1-bis- (4-hydroxyphenyl) cyclo Pentane, 1,1
-Bis- (4-hydroxyphenyl) cyclohexane,
Bis- (4-hydroxy-3-methylphenyl) methane, bis- (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane, 2, 2-bis- (4-hydroxy-3-methylphenyl) propane, 2,2-bis-
(4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis- (4-hydroxy-3-ethylphenyl) propane, 2,2-bis- (4-hydroxy-3
-Isopropylphenyl) propane, 2,2-bis-
(4-hydroxy-3-sec-butylphenyl) propane, bis- (4-hydroxyphenyl) phenylmethane, 1,1-bis- (4-hydroxyphenyl) -1-
Phenylethane, 1,1-bis- (4-hydroxyphenyl) -1-phenylpropane, bis- (4-hydroxyphenyl) diphenylmethane, bis- (4-hydroxyphenyl) dibenzylmethane, 4,4′-dihydroxydiphenyl ether , 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfide, phenolphthalein, 5,5 '-(1-methylethylidene) bis [1,1'-(biphenyl) -2-
All], [1,1′-biphenyl] -4,4′-diol, [1,1′-biphenyl] -3,3′-diol, 4,4′-oxybisphenol, bis (4-hydroxyphenyl) Examples include methanone, 2,6-dihydroxynaphthalene, and 2,7-dihydroxynaphthalene. Among them, 2,2-bis- (4-hydroxyphenyl) propane is preferred from the viewpoint of ease of production,
From the viewpoint of mechanical properties, 1,1-bis- (4-hydroxyphenyl) cyclopentane, 1,1-bis- (4-hydroxyphenyl) cyclohexane, 2,2-bis-
(4-hydroxy-3-methylphenyl) propane,
1,1-bis- (4-hydroxyphenyl) -1-phenylethane is particularly preferred. These constituent units may be polymerized singly or may be copolymerized with two or more kinds.
Further, as the polycarbonate resin, one kind may be used, or two or more kinds may be used in combination.

(II) Electrophotographic Photoreceptor In the electrophotographic photoreceptor having at least a photosensitive layer on a conductive support, the polyester resin having a polysiloxane structure used in the present invention is used as the outermost layer of the photoreceptor. It is contained in. Here, the outermost layer refers to a charge transport layer in the case of a laminated photoreceptor described later, a charge generation layer in the case of an inverted two-layer type photoreceptor, and refers to a photosensitive layer in the case of a single layer type photoreceptor. When these photoreceptors further have a layer such as an overcoat layer on the photosensitive layer, it refers to the layer.
In the present invention, when used as a binder resin or a part of the binder resin in the photosensitive layer, excellent electrophotographic properties are exhibited.

<Conductive support> As the conductive support,
For example, a metal material such as aluminum, aluminum alloy, stainless steel, copper, and nickel, or a resin material having conductivity by adding a conductive powder such as metal, carbon, and tin oxide, aluminum, nickel, and ITO (indium oxide oxide) A resin, glass, paper, or the like in which a conductive material such as tin alloy) is deposited or applied on the surface thereof is mainly used. As a form, a drum shape, a sheet shape, a belt shape, or the like is used. On a conductive support of metal material,
A conductive material having an appropriate resistance value may be applied for controlling the surface properties or covering defects.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after subjecting it to an anodic oxidation treatment, a chemical conversion treatment and the like. When the anodic oxidation treatment is performed, it is desirable to perform the sealing treatment by a known method. The surface of the support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, the support may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support.

<Undercoat Layer> An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve the adhesiveness and the blocking property. As the undercoat layer, a resin, a resin in which particles of a metal oxide or the like are dispersed, or the like is used.

Examples of the metal oxide particles used for the undercoat layer include metal oxide particles containing one kind of metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, and titanic acid. Examples include metal oxide particles containing a plurality of metal elements such as calcium, strontium titanate, and barium titanate. One type of particles may be used alone, or a plurality of types of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, Brookite, and amorphous can be used. A plurality of crystals may be included.

As the particle size of the metal oxide particles, various ones can be used. Among them, from the viewpoints of characteristics and liquid stability, the average primary particle size is preferably from 10 to 100 nm, and particularly preferably, 10 to 25 nm. The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As the binder resin used for the undercoat layer, phenoxy, epoxy, polyvinylpyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, and the like alone or together with a curing agent are cured. Among them, alcohol-soluble copolymerized polyamide, modified polyamide and the like are preferable because they show good dispersibility and coatability.

The addition ratio of the inorganic particles to the binder resin can be arbitrarily selected, but is preferably used in the range of 10 to 500% by weight in view of the stability of the dispersion and the applicability. The thickness of the undercoat layer can be arbitrarily selected, but is preferably from 0.1 to 20 μm from the viewpoint of photoreceptor characteristics and applicability. A known antioxidant may be added to the undercoat layer.

<Photosensitive Layer> (1) Layer Structure Specific constitutions of the photosensitive layer include: a charge generation layer mainly composed of a charge generation substance, a charge transport substance and a binder resin on a conductive support. A laminated photoreceptor in which charge transport layers are laminated in this order. An inverted two-layer type photoconductor in which a charge transport layer mainly composed of a charge transport substance and a binder resin and a charge generation layer mainly composed of a charge generation substance are laminated in this order on a conductive support. A single-layer (dispersion type) photoconductor in which a layer containing a charge transporting substance and a binder resin is laminated on a conductive support, and a charge generating substance is dispersed in the layer. And the like are examples of the basic form.

(2) Laminated Photosensitive Layer Charge Generating Layer In the case of a laminated photoconductor, examples of the charge generating material used for the charge generating layer include selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, and phthalocyanine. Pigment, azo pigment, quinacridone pigment, indigo pigment, perylene pigment, polycyclic quinone pigment, anthantrone pigment,
Various photoconductive materials such as organic pigments such as benzimidazole pigments can be used, and particularly preferred are organic pigments, furthermore, phthalocyanine pigments and azo pigments.

Among them, metals such as metal-free phthalocyanines, copper, indium, gallium, tin, titanium, zinc and vanadium or oxides thereof, phthalocyanines in which chloride is coordinated, azo such as monoazo, bisazo, trisazo and polyazo Pigments are preferred. When a phthalocyanine compound is used as the charge generating material, specifically, a metal such as metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or an oxide, halide, or the like thereof is used. Phthalocyanines are used. Examples of the ligand to a trivalent or higher valent metal atom include a hydroxyl group and an alkoxy group in addition to the above-described oxygen atom and chlorine atom. Especially sensitive X type, τ type metal-free phthalocyanine, α type, β type,
Preferred are titanyl phthalocyanine, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine and the like such as Y type. In addition, among the crystal forms of titanyl phthalocyanine mentioned here, α-form and β-form are described in W.C. He
It is shown by Iller et al. as phase II and phase I, respectively (Zeit. Kristallogr. 159 (1982) 173), and the β-form is known as a stable form. The most preferably used Y type is, in powder X-ray diffraction using CuKα ray,
A crystalline form characterized by a diffraction angle 2θ ± 0.2 ° showing a clear peak at 27.3 °. The phthalocyanine compound may be a single compound alone, or may be a mixture of several compounds. As the phthalocyanine compound or a mixed state that can be placed in a crystalline state here, the respective components may be mixed and used later, or the mixed state may be used in a phthalocyanine compound production / treatment step such as synthesis, pigmentation, and crystallization. It may be the one that has occurred. As such a treatment, an acid paste treatment, a grinding treatment, a solvent treatment and the like are known.

These charge generating substances include, for example, polyester resin, polyvinyl acetate, polyacrylate, polymethacrylate, polycarbonate,
It is used in a form bound with various binder resins such as polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, cellulose ester and cellulose ether. In this case, the use ratio of the charge generating substance is usually 20 to 2,000 parts by weight, preferably 30 to 500 parts by weight, more preferably 3 to 100 parts by weight based on 100 parts by weight of the binder resin.
It is in the range of 3 to 500 parts by weight.

If necessary, other organic photoconductive compounds, dyes and dyes, and electron-withdrawing compounds may be contained.
The thickness of the charge generation layer is usually 0.05 to 5 μm, preferably 0.1 to 2 μm, more preferably 0.15 to 0.8 μm.
Is preferred. Charge transport layer The charge transport layer is mainly composed of a charge transport material and a binder resin. When the charge transport layer is the outermost layer, the binder resin contains the polyester resin having a polysiloxane structure described above.

These charge transport materials include 2, 4,
Aromatic nitro compounds such as 7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron withdrawing substances such as quinones such as diphenoquinone, carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, oxa compounds Heterocyclic compounds such as diazole derivatives, pyrazoline derivatives and thiadiazole derivatives, aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine compounds, those in which a plurality of these compounds are bonded, or those compounds Electron-donating substances such as polymers having the following groups in the main chain or side chains. Among them, carbazole derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives and those in which a plurality of these derivatives are bonded are preferable, and those in which a plurality of aromatic amine derivatives, stilbene derivatives, and butadiene derivatives are bonded. Is particularly preferred.

These charge transporting substances may be used alone or in combination. The charge transport layer is formed in a state where these charge transport substances are bound to the binder resin. The charge transport layer may be composed of a single layer, or may be a laminate of a plurality of layers having different constituent components or composition ratios. The ratio of the binder resin to the charge transporting substance is usually 30 to 200 parts by weight of the charge transporting substance, preferably 40 to 150 parts by weight, and most preferably the upper limit, based on 100 parts by weight of the binder resin. 90 parts by weight or less is advantageous in maintaining the mechanical properties of the polyarylate. The film thickness is generally 10 to
It is 60 μm, preferably 10 to 45 μm, and more preferably 27 to 40 μm.

The charge transport layer has a film forming property, flexibility, coating property,
In order to improve contamination resistance, gas resistance, light resistance, etc., well-known additives such as a plasticizer, an antioxidant, an ultraviolet absorber, an electron withdrawing compound, a leveling agent, and a sensitizer may be contained. . Examples of the antioxidant include a hindered phenol compound and a hindered amine compound.

(3) Single-layer type photosensitive layer In the case of a single-layer type photosensitive layer, the same charge-generating substance and the above-mentioned charge as those of the laminated type photoreceptor are usually contained in a charge transporting medium containing the binder resin described above. The transport material is dispersed.
In this case, the particle size of the charge generating substance must be sufficiently small, preferably 1 μm or less, and more preferably 0.1 μm or less.
Those having a size of 5 μm or less are used. If the amount of the charge generating substance dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained. If the amount is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. % Range,
More preferably, it is used in the range of 1 to 20% by weight.

The thickness of the photosensitive layer is usually 5 to 50 μm, more preferably 10 to 45 μm. Also in this case, a well-known plasticizer for improving film formability, flexibility, mechanical strength, etc., an additive for suppressing residual potential, a dispersion auxiliary for improving dispersion stability, a coating property. Leveling agents, surfactants such as silicone oil,
Fluorine-based oil and other additives may be added.

(4) Other Additives Dyes and dyes optionally added to the photosensitive layer include, for example, triphenylmethane dyes such as methyl violet, brilliant green and crystal violet, thiazine dyes such as methylene blue, and quinone dyes such as quinizarin. And cyanine dyes, bilirium salts, thiavirylium salts, benzovirylium salts, and the like.

Examples of the electron-withdrawing compound include chloranil, 2,3-dichloro-1,4-naphthoquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone and phenanthrenequinone. Quinones; aldehydes such as 4-nitrobenzaldehyde; 9-benzoylanthracene;
Indandione, 3,5-dinitrobenzophenone,
2,4,7-trinitrofluorenone, 2,4,5,7
Ketones such as tetranitrofluorenone, 3,3 ', 5,5'-tetranitrobenzophenone; acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride; tetracyanoethylene, terephthalalmalononitrile, 9- Cyano compounds such as anthrylmethylidenemalononitrile, 4-nitrobenzalmalonenitrile, 4- (p-nitrobenzoyloxy) benzalmalonenitrile; 3-benzalphthalide, 3- (α-cyano-p-nitrobenzal) phthalide, Electron-withdrawing compounds such as phthalides such as 3- (α-cyano-p-nitrobenzal) -4,5,6,7-tetrachlorophthalide;

(5) Method for Forming Photosensitive Layer The photosensitive layer is prepared by dissolving a charge transporting material in a suitable solvent together with a binder resin containing a polyarylate resin according to a conventional method. Infection charges, electron-withdrawing compounds, other charge-transporting substances, or plasticizers,
It can be produced by applying a coating liquid obtained by adding a well-known additive such as a pigment to a conductive support and drying to form a photosensitive layer. In the case of a photosensitive layer comprising a charge generation layer and a charge transport layer, the above-mentioned coating solution is applied on the charge generation layer, or the charge generation layer is placed on the charge transport layer obtained by applying the above coating solution. Can be produced.

Solvents for preparing the coating solution include ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; N, N-dimethylformamide, acetonitrile; N-methylpyrrolidone,
Aprotic polar solvents such as dimethyl sulfoxide; esters such as ethyl acetate, methyl formate, and methyl cellosolve acetate; solvents that dissolve amine compounds such as chlorinated hydrocarbons such as dichloroethane and chloroform. Of course, it is necessary to select a material that dissolves the binder from these.

The photosensitive layer may contain a well-known plasticizer in order to improve film forming property, flexibility and mechanical strength. Therefore, examples of the plasticizer added to the coating solution include phthalic acid esters, phosphate esters, epoxy compounds, chlorinated paraffins, chlorinated fatty acid esters, and aromatic compounds such as methylnaphthalene. When the arylamine-based compound is used as the charge transport material in the charge transport layer, the coating solution may have the above-described composition,
Photoconductive particles, dyes, electron-withdrawing compounds, etc. may be removed or a small amount may be added. In this case, as the charge generation layer, a coating liquid obtained by dissolving or dispersing the above-mentioned photoconductive particles and a solvent such as a binder polymer or other organic photoconductive substance, a dye or an electron-withdrawing compound as necessary is applied. Examples include a dried thin layer or a layer in which the photoconductive particles are formed into a film by means such as vapor deposition.

<Other protective layers> On the photosensitive layer, an overcoat layer or the like is provided for the purpose of preventing abrasion of the photosensitive layer and preventing or reducing deterioration of the photosensitive layer due to discharge products generated from a charger and the like. May be provided. Further, for the purpose of reducing the frictional resistance and abrasion of the photoreceptor surface, the surface layer may contain a fluorine-based resin, a silicone resin, or the like.
Further, particles of these resins or particles of an inorganic compound may be included.

Further, if necessary, a layer for improving electric characteristics and mechanical characteristics such as an intermediate layer such as a barrier layer, an adhesive layer and a blocking layer, and a transparent insulating layer may be provided. Absent. <Method for Forming Each Layer> Examples of the method for applying the photosensitive layer include a spray coating method, a spiral coating method, a ring coating method, and a dip coating method.

As the spray coating method, air spray,
There are airless spray, electrostatic air spray, electrostatic airless spray, rotary atomizing electrostatic spray, hot spray, hot airless spray, etc., considering the degree of atomization and adhesion efficiency to obtain a uniform film thickness. In the rotary atomization type electrostatic spray, the transporting method disclosed in the re-published Hei 1-805198, that is, by continuously transporting a cylindrical workpiece while rotating it without spacing in the axial direction thereof, It is possible to obtain an electrophotographic photoreceptor excellent in uniformity of film thickness with high deposition efficiency overall.

The spiral coating method is disclosed in
Japanese Patent Application Laid-Open No. 1-231966
There is a method disclosed in Japanese Patent Application Laid-Open No. HEI 11-193716, in which the paint is continuously flew from a minute opening in a streak shape, and a method using a multi-nozzle body disclosed in JP-A-3-193161.

Hereinafter, the dip coating method will be described. Using a charge transport material (preferably the above-mentioned compound), a polyarylate resin, a solvent or the like, the total solid content concentration is usually 25 to 40.
%, And a coating solution for forming a charge transport layer having a viscosity of usually 50 to 300 centipoise, preferably 100 to 200 centipoise. Here, the viscosity of the coating liquid is substantially determined by the type and molecular weight of the binder polymer,
If the molecular weight is too low, the mechanical strength of the polymer itself decreases, so it is preferable to use a binder polymer having a molecular weight that does not impair the mechanical strength. The charge transport layer is formed by a dip coating method using the coating solution thus adjusted.

Thereafter, the coating film is dried, and the drying temperature and time are preferably adjusted so that necessary and sufficient drying is performed. The drying temperature is usually 100 to 250 ° C, preferably 110 to 17 ° C.
0 ° C, more preferably in the range of 120 to 140 ° C. As a drying method, a hot air dryer, a steam dryer, an infrared dryer, a far infrared dryer, or the like can be used.
The electrophotographic photoreceptor thus obtained has high sensitivity, low residual potential, high chargeability, and small variation due to repetition, and in particular, good charge stability affecting image density, It can be used as a highly durable photoreceptor. Further, since the sensitivity is high in the range of 750 to 850 nm, it is particularly suitable for a photoconductor for a semiconductor laser printer.

<Electrophotographic Apparatus> An electrophotographic apparatus, such as a copying machine or a printer, using the electrophotographic photosensitive member of the present invention includes at least each of charging, exposure, development, and transfer processes. Any of the methods may be used. As a charging method (charging device), for example, corotron or scorotron charging using corona discharge,
Any of contact charging with a conductive roller, a brush, a film, or the like may be used. Among them, in the charging method using corona discharge, scorotron charging is often used in order to keep the dark area potential constant. As a developing method, a general method of developing by contacting or non-contacting a magnetic or non-magnetic one-component developer, a two-component developer or the like is used. As a transfer method, any of a method using corona discharge, a method using a transfer roller or a transfer belt, and the like may be used. The transfer may be performed directly on paper, an OHP film, or the like, or may be once transferred onto an intermediate transfer body (belt or drum shape) and then transferred onto paper or an OHP film.

Usually, after the transfer, a fixing process for fixing the developer to paper or the like is used. As a fixing means, generally used heat fixing, pressure fixing and the like can be used. In addition to these processes, a process such as cleaning and static elimination that is usually used may be provided.

[0058]

EXAMPLES Hereinafter, specific embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not intended to be limited by these Examples unless it exceeds the gist thereof. [Production of Polyester Resin] Production Example 1 (Production Method of Polyester Resin (A-1) of Example 1) Sodium hydroxide (4.72 g) and H _{2 were} placed in a 1 L beaker.
O (400 ml) was weighed and dissolved while stirring with nitrogen bubbling. There, a polysiloxane derivative represented by the following structural formula (4-1) (average degree of polymerization n =
43) (0.45 g), p-tert-butylphenol (0.1966 g), benzyltriethylammonium chloride (0.0587 g) and bis (4-hydroxy-3,5-dimethylphenyl) methane [= tetramethylbisphenol F] (11.41 g) in that order, and after stirring, the aqueous alkali solution was transferred to a 2 L reaction tank.

[0059]

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Separately, isophthalic acid chloride (2.76)
g) and terephthalic acid chloride (6.44 g) were dissolved in dichloromethane (200 ml) and transferred into a dropping funnel. While maintaining the external temperature of the polymerization tank at 20 ° C., while stirring the aqueous alkali solution in the reaction tank, a dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 3 hours, acetic acid (1.55 ml) and dichloromethane (100
ml) and water (50 ml) were added and stirred for 30 minutes. Thereafter, the stirring was stopped and the organic layer was separated. This organic layer is treated with 0.
Was washed with 1N sodium hydroxide solution (450 ml), then performed twice washed with 0.1N hydrochloric acid (450 ml), was carried out two more times washed with H ₂ O (450ml). The washed organic layer was diluted by adding 200 ml of methylene chloride, poured into methanol (2000 ml), and the resulting precipitate was taken out by filtration and dried to obtain the desired polyester resin (A-1). The viscosity average molecular weight of the obtained polyester resin (A-1) was 37,600.
The structural formula of the obtained polyester resin (A-1) is shown below.

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[Measurement of Viscosity Average Molecular Weight] A polyester resin was dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. Flow time t of the solvent (dichloromethane)
_Using a Ubbelohde capillary viscometer with ₀ at 136.16 seconds, the flow time t of the sample solution in a constant temperature water bath set at 20.0 ° C. was measured. According to the following formula, the viscosity average molecular weight M
v was calculated.

[0063]

A = 0.438 × η _sp +1 η _sp = t / t ₀ −1 b = 100 × η _sp / C C = 6.00 (g / L) η = b / a Mv = 3207 × η ^1.205 Production Example 2 (Production Method of Polyester Resin (A-2) of Example 2) Sodium hydroxide (4.72 g) and H ₂ were ^{placed in a} 1 L beaker.
O (400 ml) was weighed and dissolved while stirring with nitrogen bubbling. To this were added p-tert-butylphenol (0.1967 g), benzyltriethylammonium chloride (0.0587 g) and bis (4-hydroxy-3,5-dimethylphenyl) methane [= tetramethylbisphenol F] (11.42 g). After sequentially adding and stirring, the aqueous alkali solution was transferred to a 2 L reaction tank. Separately, isophthalic acid chloride (2.76 g),
Terephthalic acid chloride (6.44 g) and a polysiloxane derivative represented by the following structural formula (4-2) (average degree of polymerization of polysiloxane n = 43) (0.44 g) are dissolved in dichloromethane (200 ml) and placed in a dropping funnel. Moved.

[0064]

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While maintaining the external temperature of the polymerization vessel at 20 ° C., while stirring the aqueous alkali solution in the reaction vessel, a dichloromethane solution was added dropwise from the dropping funnel over 1 hour, and the mixture was further stirred for 3 hours. .55 ml), dichloromethane (100 ml) and water (50 ml) were added and stirred for 30 minutes. Thereafter, the stirring was stopped and the organic layer was separated. The organic layer is washed with a 0.1 N aqueous sodium hydroxide solution (450 ml), then twice with 0.1 N hydrochloric acid (450 ml), and twice with H ₂ O (450 ml). went.

320 ml of methylene chloride was added to the washed organic layer.
Was added, and the mixture was poured into methanol (2000 ml), and the obtained precipitate was taken out by filtration and dried to obtain a target polyester resin. The obtained polyester resin (A
The structure of -2) is shown in the following structural formula (4-2). The viscosity average molecular weight of the obtained polyester resin was 43,000.

[0067]

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Production Example 3 (Production method of polyester resin of Example 3) Structural formula (4-2) described in Production Example 2 in place of Polysiloxane derivative of Structural Formula (4-1) in Production Example 1 A polysiloxane polyester block copolymer was obtained in the same manner except that 0.44 g of the polysiloxane derivative (n = 43) shown in (1) was used. The structure of the obtained block copolymer was the same as that of the polyester resin (A-2) shown in Production Example 2, and the viscosity average molecular weight was 37,400.

Production Example 4 (Method for producing polyester resin of Example 4) In Production Example 2, the polysiloxane derivative represented by the structural formula (4-2) was changed to 0.44 g, and the structural formula (4 -1) polysiloxane derivative (n = 43)
A polyester was produced in the same manner as in Production Example 2, except that 0.18 g was used, in which the polysiloxane having a structure represented by the polyester resin (A-1) described in Production Example 1 was graft-copolymerized. The viscosity average molecular weight of the obtained polyester resin was 49,800. Comparative Production Example 1 (Method for Producing Polyester Resin of Comparative Example 1) The structural formula (4-
Production Example 4 except that the charged amount of the polysiloxane derivative (n = 43) shown in 1) was changed from 0.18 g to 0.90 g.
A polyester was produced in the same manner as in the above. The obtained polyester had a structure represented by the polyester resin (A-1) described in Production Example 1, and had a viscosity average molecular weight of 49,300.

Example 1 Production of photoreceptor (Production of charge generation layer) 10 parts by weight of β-type oxytitanium phthalocyanine having the following structure was added to 4-methoxy-4
-Methylpentanone-2 In addition to 150 parts by weight, a pulverization and dispersion treatment was performed with a sand grind mill.

[0071]

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Further, 100 parts of a 5% 1,2-dimethoxyethane solution of polyvinyl butyral (Denka Butyral # 6000C, manufactured by Denki Kagaku Kogyo KK) and a phenoxy resin (PKH, manufactured by Union Carbide Co., Ltd.)
H) was mixed with 100 parts of a 5% 1,2-dimethoxyethane solution to prepare a binder solution. To 160 parts by weight of the previously prepared pigment dispersion, 100 parts by weight of a binder solution,
An appropriate amount of 1,2-dimethoxyethane was added to finally prepare a dispersion having a solid concentration of 4.0%. The thus obtained dispersion was applied on a polyethylene terephthalate film on which aluminum was vapor-deposited on the surface so as to have a thickness of 0.4 μm to form a charge generation layer. (Production of charge transport layer) Next, on this film, 60 parts of the following charge transport material [1]

[0073]

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Further, 100 parts of the polyester resin (viscosity average molecular weight 37,600) having a polysiloxane graft copolymerization amount of 2.5% by weight obtained in Production Example 1 and 0.03 part of a silicone oil as a leveling agent were mixed with toluene /
A solution dissolved in a mixed solvent of tetrahydrofuran (2/8 by weight) was applied, dried at 125 ° C. for 20 minutes, and a charge transport layer was provided so that the film thickness after drying was 20 μm. At this time, the solubility of the polyester resin was good. The photoconductors thus obtained were evaluated as described below. [Friction test] The toner was placed on the photoreceptor prepared above at 0.
1 cm / cm 2 of urethane rubber of the same material as the cleaning blade is placed on the surface to be evenly contacted and contacted to 1 mg / cm 2 for 1 cm.
It is used at an angle of 45 degrees and cut at a load of 20
The 100th kinetic friction coefficient when urethane rubber was moved 100 times at 0 g, at a speed of 5 mm / sec, and a stroke of 20 mm was measured with a fully automatic friction and wear tester DFPM-SS manufactured by Kyowa Interface Chemical Co., Ltd. Table 1 shows the results.

[Electrical Characteristics] An electrophotographic characteristic evaluation apparatus manufactured in accordance with the standards of the Electrophotographic Society of Japan (Basic and Application of Continuous Electrophotographic Technology, edited by the Electrophotographic Society, Corona, 404-40)
5), the above-mentioned photoreceptor was adhered to an aluminum drum to form a cylinder, and after the aluminum drum and the aluminum base of the photoreceptor were electrically connected, the drum was rotated at a constant rotation speed. An electrical property evaluation test was performed by a cycle of charging, exposure, potential measurement, and static elimination. that time,
The initial surface potential was -700 V, monochromatic light of 780 nm for exposure and 660 nm for static elimination, and light of 780 nm was used for 2.
The surface potential (VL) at the time of irradiation of 4 μJ / cm 2 was measured. In the VL measurement, the time required for the exposure-potential measurement was 139 ms. The measurement environment was a temperature of 5 ° C. and a relative humidity of 10% (L / L) and a temperature of 25 ° C. and a relative humidity of 50%.
Performed under (N / N). Table 1 shows the results. The smaller the absolute value of the surface potential (VL), the better the response.

Example 2 A polyester block copolymer having a polysiloxane copolymerization amount of 2.5% by weight produced in Production Example 2 was replaced with the polyester resin used in the production of the photoreceptor of Example 1 (production of the charge transport layer). Except for using a coalescence (viscosity average molecular weight 43,000),
The same operation as in Example 1 was performed to manufacture a photoconductor. At this time, the solubility of the polyester resin was good. The friction test and the evaluation of the electrical characteristics of the obtained photoreceptor were performed in the same manner as in Example 1 under the same conditions. Table 1 shows the results.

Example 3 A block copolymer having a polysiloxane copolymerization amount of 2.5% by weight produced in Production Example 3 was replaced with the polyester resin used in the production of the photoconductor of Example 1 (production of the charge transport layer). A photoconductor was manufactured by the same operation as in Example 1 except that (viscosity average molecular weight 37,400) was used. At this time, the solubility of the polyester resin was good. The friction test and the evaluation of the electrical characteristics of the obtained photoreceptor were performed in the same manner as in Example 1 under the same conditions. Table 1 shows the results.

Example 4 In place of the polyester resin used in the production of the photoreceptor of Example 1 (production of the charge transport layer), a graft copolymer having a polysiloxane copolymerization amount of 2.5% by weight produced in Production Example 4 A photoconductor was manufactured by the same operation as in Example 1 except that (viscosity average molecular weight 49,800) was used. At this time, the solubility of the polyester resin was good. The friction test and the evaluation of the electrical characteristics of the obtained photoreceptor were performed in the same manner as in Example 1 under the same conditions. Table 1 shows the results.

Example 5 In the production of the photoreceptor of Example 1 (production of the charge transport layer), 100 parts of the polyester resin of Production Example 1 was used, and Comparative Production Example 1 was used.
50 parts by weight of a polyester resin having a polysiloxane graft copolymerization amount of 5% by weight and 50 parts by weight of a polyester resin (B-1) shown below (viscosity average molecular weight 4
A photoconductor was prepared in the same manner as in Example 1, except that 3,700) was used.

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A friction test and an evaluation of electrical characteristics of the obtained photoreceptor were performed in the same manner as in Example 1 under the same conditions. Table 1 shows the results. Example 6 In the production of the photoreceptor of Example 1 (production of the charge transport layer), 100 parts of the polyester resin of Production Example 1 was replaced with Comparative Production Example 1.
A photoconductor was prepared in the same manner as in Example 1, except that 50 parts by weight of a polyester resin having a polysiloxane graft copolymerization amount of 5% by weight and 50 parts by weight of a polycarbonate resin (B-2) shown below were used. .

[0082]

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A friction test and an evaluation of electrical characteristics of the obtained photoreceptor were performed in the same manner as in Example 1 under the same conditions. Table 1 shows the results. Comparative Example 1 In the production of the photoreceptor of Example 1 (production of the charge transport layer), 100 parts of the polyester resin of Example 1 was used.
Example 1 except that 100 parts of the polyester resin having a polysiloxane graft copolymerization amount of 5.0% by weight obtained in the above was changed to 100 parts.
A photoreceptor was prepared in the same manner as described above.

A friction test and an evaluation of the electrical characteristics of the obtained photoreceptor were performed in the same manner as in Example 1 under the same conditions. Table 1 shows the results. Comparative Example 2 In the production of the photoreceptor of Example 1 (production of the charge transporting layer), 100 parts of the polyester resin of Example 1 was replaced with the polyester resin (B-1) (viscosity average molecular weight 4) used in Example 5.
(3,700) A photoconductor was prepared in the same manner as in Example 1, except that 100 parts were changed.

A friction test and an evaluation of the electrical characteristics of the obtained photoreceptor were performed in the same manner as in Example 1 under the same conditions. Table 1 shows the results.

[0086]

[Table 1]

From the above results, by using a binder resin or a resin composition having a specific content of polysiloxane in the binder resin, it is possible to obtain an electrophotographic photosensitive material having excellent slipperiness while maintaining good electrical characteristics. It turns out that the body is obtained.

[0088]

According to the present invention, the binder resin or the resin composition having a polysiloxane having a specific polysiloxane content has a significantly lower coefficient of friction than ordinary polyester resins while maintaining good electrical properties. Therefore, by using this resin, it is possible to obtain an electrophotographic photosensitive member having good electric characteristics and excellent surface slipperiness.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Lingo 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation Yokohama Research Laboratory F-term (reference) 2H068 AA13 BB25 BB27 BB33 BB54

Claims (6)

[Claims] 1. An electrophotographic photosensitive member having at least a photosensitive layer on a conductive substrate, wherein the outermost layer of the photosensitive member contains a polyester resin having a polysiloxane structure, and the polyester resin has a polysiloxane content of the entire binder. An electrophotographic photoreceptor characterized in that the content is 0.1% by weight or more and less than 5% by weight in the resin. 2. The electrophotographic photoreceptor according to claim 1, wherein the polyester resin has a polysiloxane content of 0.2 to 3% by weight based on the whole binder resin. 3. The electrophotographic photoreceptor according to claim 1, wherein a main component of the binder resin is polyester and / or polycarbonate. 4. The electrophotographic photoreceptor according to claim 1, wherein the polysiloxane is represented by the following general formula (1). Embedded image (In the general formula (1), R ¹ and R ² represent an alkyl group which may have a substituent or an aromatic group which may have a substituent, and n represents an integer of 1 to 500.) 5. The polyester resin has a repeating unit represented by the following general formula (2).
The electrophotographic photosensitive member according to any one of the above. Embedded image (In the general formula (2), R ^{6 to} R ¹³ are each independently a hydrogen atom, an optionally substituted alkyl or alkoxyl group having 1 to 20 carbon atoms, a halogen atom, or an optionally substituted aromatic group. X represents a single bond, an alkylene group, a cycloalkylene group, an oxygen atom or a sulfur atom, and Y represents a divalent organic group.) 6. The electrophotographic photosensitive member according to claim 5, wherein X in the general formula (2) is —CH ₂ —.