JP2002265574A - Polyester resin and electrophotographic photosensitive material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin which excels in both abrasion resistance and sliding properties, and an electrophotographic photosensitive material using the polyester resin in the photosensitive layer. SOLUTION: The polyester resin contains a repeating unit to be represented by formula (1) (wherein R1 -R8 are each independently hydrogen atom or a substituent; X is a single bond or a divalent connecting group; and Y is a divalent organic connecting group) in the structural formula, and has a viscosity average molecular weight of 10,000-200,000, and is used as the binder resin for the photosensitive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin having a specific structure and an electrophotographic photosensitive member using the polyester resin as a binder for a photosensitive layer.

[0002]

2. Description of the Related Art In recent years, electrophotographic technology has been widely applied not only to the field of copiers but also to the field of various printers since a high-quality image can be immediately obtained. Photoconductors (electrophotographic photoconductors) used in electrophotography
Since it is repeatedly used in an electrophotographic process, that is, in a cycle of charging, exposure, development, transfer, cleaning, static elimination, etc., it is deteriorated by receiving various stresses during the process.
As such deterioration, for example, strongly oxidizing ozone or NOx generated from a corona charger commonly used as a charger may cause chemical damage to the photosensitive layer or a carrier ( (Electric current) flows through the photosensitive layer, or the photosensitive layer composition is decomposed by static elimination light or external light, resulting in chemical, electrical, or optical deterioration. Another example is mechanical deterioration such as abrasion of the photosensitive layer surface, generation of scratches, and peeling of the film due to rubbing with a cleaning blade or a magnetic brush or contact with a developer or paper.

[0003] In particular, mechanical deterioration such as damage to the surface of the photosensitive layer such as the latter easily affects the copy image and directly impairs the image quality. It is a factor. Therefore, in order to develop a photoreceptor having a long life, it is essential to increase the strength against a mechanical load in addition to increasing the chemical, electrical, and optical durability.

In the case of a stacked type photoreceptor, a charge transfer layer (hereinafter sometimes referred to as a charge transport layer) is generally subjected to such a mechanical load. The charge transfer layer is usually composed of a binder resin and a charge transfer material (hereinafter sometimes referred to as a charge transport material), and the binder resin substantially determines the strength against a mechanical load.

[0005]

However, since the amount of the charge transfer material to be added to the charge transfer layer is considerably large, it is not easy to select an appropriate binder resin to give the photoreceptor sufficient mechanical strength. . Conventionally, as a binder resin for a charge transfer layer of an electrophotographic photoreceptor, vinyl polymers such as polymethyl methacrylate, polystyrene, polyvinyl chloride and the like, copolymers thereof, polycarbonate, polyester, polysulfone, phenoxy, epoxy, silicone resin, etc. Thermoplastic resins and various thermosetting resins are used.

Among these numerous binder resins, polycarbonate resins have relatively excellent performance, and various polycarbonate resins have been developed and put to practical use. For example, JP-A-50-983
No. 32 discloses a bisphenol P type polycarbonate, and JP-A-59-71057 discloses a bisphenol Z-type polycarbonate.
No. 4251 discloses a copolymer type polycarbonate of bisphenol P and bisphenol A.
JP-A-21478 discloses a polycarbonate copolymer containing a bis (4-hydroxyphenyl) ketone type structure as a binder resin.

However, many conventional organic photoconductors, including photoconductors using such a polycarbonate resin as a binder resin, have practical loads such as development with toner, friction with paper, and rubbing with a cleaning member (blade). Has a drawback that the surface is worn or scratched on the surface, so that at present the printing performance is limited.

On the other hand, there is an example in which an aromatic polyester is used as a binder resin in order to increase the mechanical strength of the photoreceptor. For example, JP-A-56-135844 discloses a technique of an electrophotographic photoreceptor using a polyarylate (aromatic polyester) resin commercially available under the trade name "U-Polymer" as a binder. Among them, it is shown that the sensitivity is particularly excellent as compared with polycarbonate. JP-A-3-6567 discloses an electrophotographic photoreceptor characterized in that it contains a polyarylate (aromatic polyester) copolymer having a structure using tetramethylbisphenol F and bisphenol A as a bisphenol component. Have been.

However, these aromatic polyesters are
There are drawbacks in that the solubility of the photosensitive layer in a coating solvent and the stability of the solution are poor, and when these are used as a binder for the photosensitive layer, the electrical characteristics are deteriorated. In particular,
According to the technique disclosed in the former publication, although the abrasion resistance and the sensitivity are slightly improved, the stability of the coating solution is poor, so that the coating cannot be manufactured or the slip property is reduced even if possible. Is bad. Further, in the technique described in the latter publication, improvement is seen in the abrasion resistance as compared with the conventional polycarbonate, but no superiority is recognized in the slipperiness in comparison with the polycarbonate.

In addition, in order to increase the mechanical strength of the photoreceptor, for example, a method of providing an overcoat layer (JP-A-61-72256) and a method of using a binder polymer having high abrasion resistance (JP-A-61-72256) Japanese Patent Application Laid-Open No. 63-148263, Japanese Patent Application Laid-Open No. 3-221962) and the like have been proposed, but all of them have problems such as insufficient effects and adverse effects on characteristics such as electric characteristics. is the current situation.

That is, none of the above-mentioned prior arts simultaneously satisfy both abrasion resistance (scratch resistance) and surface slippage of an electrophotographic photosensitive member. Therefore, as a material of the binder resin for the electrophotographic photoreceptor, a material having both excellent abrasion resistance and slipperiness is desired. The object of the present invention is to solve the above problems,
An object of the present invention is to provide a polyester resin excellent in both abrasion resistance and slipperiness, and an electrophotographic photosensitive member using the polyester resin in a photosensitive layer.

[0012]

The inventors of the present invention have studied the binder resin used in the photosensitive layer in detail, and as a result, have found that a polyester resin produced by copolymerizing or homopolymerizing a repeating unit having a specific structure is: The present invention has been found to have excellent sliding properties and high abrasion resistance as well as good storage stability of a coating solution because it shows high solubility in non-halogen solvents as well.

That is, the gist of the present invention is to provide a polyester resin comprising a repeating unit represented by the following general formula (1) in the structural formula and having a viscosity average molecular weight of 10,000 to 200,000; An object of the present invention is to provide an electrophotographic photosensitive member using a polyester resin as a binder resin for a photosensitive layer.

Embedded image In ... formula (1) (Formula (1), R ₁ to R ₈ each independently represent a hydrogen atom or a substituent. Further, X represents a single bond or a divalent linking group, Y is 2 Represents a valent organic linking group.)

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. (Polyester resin) The polyester resin of the present invention is mainly used as a binder resin for an electrophotographic photoreceptor, but as other uses, a sliding material, a molding material, an optical material, a transparent film material, a coating material, and abrasion resistance imparting. It can also be used for agents, optical functional resins, resist materials and the like.

The polyester resin of the present invention has a repeating unit having the structure represented by the general formula (1). R _{1 to} R ₈ in the two aromatic rings in the general formula (1) are each independently a hydrogen atom or a substituent. As the substituent, those which do not impair the properties of the polyester resin intended in the present invention can be selected. Specifically, each of them independently represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group. Group, isobutyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, etc., an alkyl group having about 1 to 10 carbon atoms, methoxy group, ethoxy group, etc. Examples include an alkoxy group of about several to about 10, a halogen group such as fluorine, chlorine, and bromine, and a nitro group. However, most preferably, R _{1 to} R _{8 are} all hydrogen atoms. In other words,
These two aromatic rings are most preferably each an unsubstituted divalent benzene ring.

X in the general formula (1) is a single bond or 2
Is a valent linking group. As the divalent linking group, those which do not impair the properties of the polyester resin intended in the present invention can be selected. Specifically, -O -, - and divalent element group such as _{S-, -CH 2 -, - (} CH 2) 2 -, - (CH 2)
₃ −,

Embedded image And a divalent organic linking group containing an alkylene group or a cycloalkylene group. Among these divalent linking groups, -CH ₂ -, or

Embedded image Is preferred. Y in the general formula (1) is a divalent organic linking group, and any one which does not impair the properties of the polyester resin intended in the present invention can be selected. Specifically, for example,
1,4-phenylene group, 1,3-phenylene group, 1,2
- phenylene group, a naphthylene group, a divalent aromatic group such as 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
And a divalent aliphatic group such as H-. Among them, a divalent aromatic group is preferable. Specifically, 1,4-phenylene group, 1,3-phenylene group, naphthylene group, biphenylene group, and —CH 好 ま し い CH— are more preferable, and 1,4-phenylene group and 1,3-phenyl are more preferable. A phenylene group. Most preferably, the repeating unit of the general formula (1) is a chemical formula (1).

Embedded image ... Chemical formula (1) The viscosity average molecular weight of the polyester resin of the present invention is 10,000 to 2
Although it is 0,000, it is preferably 15,000 to 100,000, and more preferably 18,000 to 50,000. If the viscosity average molecular weight is too small, mechanical strength and abrasion resistance decrease. Also,
If the viscosity average molecular weight is too large, the viscosity of the coating solution is so high that coating becomes difficult.

The content of the structural unit represented by the general formula (1) with respect to the entire polyester resin of the present invention is from 1 to 1.
It is 100% by weight, preferably 5 to 90% by weight, more preferably 10 to 70% by weight. In the polyester resin of the present invention, the dihydric alcohol or dihydric phenol which is a component other than the repeating component of the general formula (1) is, specifically, hydroquinone, resorcinol, 1,3-dihydroxynaphthalene as an aromatic diol. 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-hydroxyphenyl) ethane (B
PE), 1,1-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) propane (BPA), bis- (4-hydroxy-3,5-
Dimethylphenyl) methane (TmBPF), 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. Preferred examples among these are bis-
(4-hydroxyphenyl) methane (BPF), 1,1
-Bis- (4-hydroxyphenyl) ethane (BP
E), 2,2-bis- (4-hydroxyphenyl) propane (BPA), bis- (4-hydroxy-3,5-dimethylphenyl) methane (TmBPF), 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 (BPC) 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 (Tm
a), bis- (4-hydroxy-3,6-dimethylphenyl) methane (Xf) and 1,1-bis- (4-hydroxyphenyl) -1-phenylethane (BPP). Particularly preferred are 2,2-bis- (4-hydroxyphenyl) propane (BPA), bis- (4-hydroxy-3,5-dimethylphenyl) methane (TmBP)
F), 1,1-bis- (4-hydroxyphenyl) cyclohexane (BPZ) and 2,2-bis- (4-hydroxy-3-methylphenyl) propane (BPC).
Examples of the aliphatic dihydroxy compound include ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-pentanediol, pentamethylenediol, 2,4-pentanediol, 1,5-hexanediol, and hexamethylene glycol. , 1,5-heptanediol, heptamethylenediol, octamethylenediol, 1,9-nonanediol, 1,10-decamethyleneglycol, 1,6-cyclohexanediol, etc., preferably ethylene glycol, propylene Glycol and 1,4-butanediol.

In particular, the constituent components other than the repeating component of the general formula (1) in the polyester resin of the present invention are preferably repeating units represented by the following general formula (2).

Embedded image In ... formula (2) (formula (2), R _'1 to R' ₈ each independently represent a hydrogen atom or a substituent. Also, X 'represents a single bond or a divalent linking group, Y ′ represents a divalent organic linking group.) In the general formula (2), R ′ _{1 to} R ′ ₈ each independently represent
It is a hydrogen atom or a substituent. As the substituent, those which do not impair the properties of the polyester resin intended in the present invention can be selected. Specifically, R _{1 to} R _{8 in the} general formula (1) can be used.
Similarly to the above, an alkyl group having about 1 to 10 carbon atoms, an alkoxy group having about 1 to 10 carbon atoms, a halogen group, and the like can be independently mentioned.

X 'in the general formula (2) is a single bond or a divalent linking group. As the divalent linking group, those which do not impair the properties of the polyester resin intended in the present invention can be selected. Specifically, similarly to X in the general formula (1), -O- and -S- And a divalent organic linking group such as an alkylene group and a cycloalkylene group.

Further, Y ′ in the general formula (2) can be selected from divalent organic linking groups which do not impair the properties of the polyester resin intended in the present invention. Specifically, similarly to Y in the general formula (1), a divalent aromatic group, a divalent aliphatic group and the like can be mentioned. The content of the components other than the repeating unit of the general formula (1) with respect to the entire polyester resin of the present invention is usually 1 to 99% by weight, preferably 10 to 95% by weight, more preferably 30 to 90% by weight. weight%
It is.

The polyester resin of the present invention may be a copolymer with another resin. The copolymerization type may be any of block, graft and multi-block copolymerization. Other resin structures copolymerized here include polysulfone, polyether, polyketone, polyamide,
Various resins such as polysiloxane, polyimide, polystyrene, and polyolefin are exemplified. The amount of the other resin which is a copolymer component other than the polyester of the present invention is usually 50 mol% or less, preferably 30 mol% or less, and most preferably 10 mol% or less in the whole copolymer.

The polyester resin of the present invention can be mixed with other resins and used for an electrophotographic photosensitive member or the like.
Examples of other resins mixed here include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride and copolymers thereof, and thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resins. And the like. Among these, polycarbonate resins are preferred. The amount of the other resin used in combination with the polyester resin of the present invention is usually 50% by weight or less based on all binder resins,
Preferably not more than 30% by weight, most preferably 10% by weight
It is as follows. When the polyester resin of the present invention is used as a surface slippage modifier or a flame retardant, it is 50% by weight or less, preferably 20% by weight or less, and most preferably 5% by weight or less based on all resins. May be mixed with a polyester or other resin not containing a polysiloxane structure.

As the method for producing the polyester resin of the present invention, known polymerization methods can be used, and specific examples include an interfacial polymerization method, a melt polymerization method, and a solution polymerization method. For example, in the case of production of a polyester resin by an interfacial polymerization method, a solution obtained by dissolving at least one kind of bifunctional phenol component or bisphenol component in an aqueous alkali solution and a solution obtained by dissolving at least one kind of aromatic dicarboxylic acid chloride component are used. Mix with the hydrocarbon solution. In this case, a quaternary ammonium salt or a quaternary phosphonium salt can be used as a catalyst. From the viewpoint of productivity, the polymerization temperature is usually preferably in the range of 0 to 40 ° C, and the polymerization time is preferably in the range of 2 to 12 hours. After polymerization,
The desired resin can be obtained by separating the aqueous phase and the organic phase and washing and recovering the polymer dissolved in the organic phase by a known method.

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 from 1.0 to phenolic hydroxyl groups contained in the reaction system.
A range of 3 equivalents is preferred. Examples of the halogenated hydrocarbon used here include 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, bromate and iodate, benzyltriethylammonium chloride, benzyltrimethyl and the like. Ammonium chloride, benzyltributylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, trioctylmethylammonium chloride, tetrabutylphosphonium bromide, triethyloctadecylphosphonium bromide, N-laurylpyridinium chloride, laurylpicolinium chloride, etc. No.

Specific examples of the bifunctional phenol component or bisphenol component include the above-mentioned aromatic diols, and one or more of these may be used in combination. Phenol, o, m, p-cresol, o, m, p-ethylphenol, o, m, p-propylphenol, o, m, p-tert-butylphenol, pentyl Alkylphenols such as phenol, hexylphenol, octylphenol and nonylphenol, o, m, p-phenylphenol, 2,4,6-
Monofunctional phenols such as trimethylphenol, 2,3,6-trimethylphenol, acetic chloride, butyric chloride, octyl chloride, benzoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, benzenephosphonyl chloride and the like A monofunctional acid halide such as a substituent may be present.

As a method for purifying the resin after polymerization, the resin solution is washed with an aqueous alkali solution such as sodium hydroxide or potassium hydroxide, an aqueous acid solution such as hydrochloric acid, nitric acid, phosphoric acid, water, etc., and then separated by standing. Alternatively, the liquid may be separated by centrifugation or the like.
Further, a method of precipitating a solution of the generated resin in a solvent in which the resin is insoluble, a method of dispersing the resin solution in hot water and distilling off the solvent, or a method of flowing the resin solution through an adsorption column or the like, The resin may be purified.

The purified resin is precipitated in water, alcohol or other organic solvent in which the resin is insoluble, or the solvent of the resin solution is distilled off in warm water or a dispersion medium in which the resin is insoluble, or heated, reduced in pressure, etc. Can be taken out by distilling off the solvent. When the produced resin is in a slurry state, it can be taken out as a solid by a centrifuge, a filter or the like.

The obtained resin is usually dried at a temperature not higher than the decomposition temperature of the resin, but is preferably dried under reduced pressure within the range of 20 ° C. to the melting temperature of the resin. Drying is performed until the purity of impurities such as the residual solvent becomes equal to or less than a certain level, but usually the residual solvent is 1000 ppm or less, preferably 300 ppm.
Thereafter, the drying is more preferably performed until the concentration becomes 100 ppm or less.

(Electrophotographic Photoreceptor) Next, the electrophotographic photoreceptor as an application of the polyester resin of the present invention will be described in detail below. The electrophotographic photoreceptor using the resin of the present invention usually has a photosensitive layer on a conductive support,
Examples of the conductive support include metal materials such as aluminum, aluminum alloys, stainless steel, copper, and nickel, and resin materials to which conductive powder such as metal, carbon, and tin oxide is added to impart conductivity. Resins, glass, paper, and the like, in which a conductive material such as aluminum, nickel, or ITO (indium tin oxide alloy) is deposited or applied on the surface thereof, are mainly used. As the form, a drum shape, a sheet shape, a belt shape or the like is used. A conductive material having an appropriate resistance value may be applied on a conductive support made of a metal material for controlling conductivity and surface properties and 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 or the like. When the anodic oxidation treatment is performed, it is desirable to perform the sealing treatment by a known method. The support surface may be smooth, or by using a special cutting method or by performing a polishing treatment,
It may be roughened. Further, the support may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support.

An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used. Examples of 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, calcium titanate, and titanium. Examples include metal oxide particles containing a plurality of metal elements such as strontium acid 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. Titanium oxide particles have tin oxide, aluminum oxide, antimony oxide,
Treatment with an inorganic substance such as zirconium oxide or silicon oxide or an organic substance such as stearic acid, polyol, or silicon may be performed. 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, the average primary particle size is preferably 10 to 100 nm, particularly preferably 10 to 100 nm, from the viewpoint of the characteristics and the stability of the liquid. ２５25 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 are used alone or together with a curing agent. Among them, alcohol-soluble copolymerized polyamides, modified polyamides and the like are preferable because they exhibit good dispersibility and coatability.

Although the addition ratio of the inorganic particles to the binder resin can be arbitrarily selected, it 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 from the viewpoint of photoreceptor characteristics and applicability, is 0.1 to 20 μm.
m is preferred. A known antioxidant may be added to the undercoat layer.

The specific constitution of the photosensitive layer of the electrophotographic photosensitive member is as follows: a charge generation layer mainly composed of a charge generation substance on a conductive support, a charge transport substance and a charge transport mainly composed of a binder resin. A laminated photoconductor in which 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 given as basic configuration examples.

In the case of a laminated photoreceptor, examples of the charge generating substance used in the charge generating layer include selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials,
Various photoconductive materials such as phthalocyanine pigments, azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthantrone pigments, and organic pigments such as benzimidazole pigments can be used. Is preferred.

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, monoazo, bisazo, trisazo, and polyazos. Azo pigments are preferred. When a phthalocyanine compound is used as the charge generating substance of the electrophotographic photoreceptor,
Specifically, metal-free phthalocyanine, copper, indium,
Gallium, tin, titanium, zinc, vanadium, silicon,
Coordinated phthalocyanines such as a metal such as germanium or an oxide or halide thereof 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. Particularly preferred are high-sensitivity X-type, τ-type metal-free phthalocyanines, α-type, β-type, and Y-type titanyl phthalocyanines, vanadyl phthalocyanines, chloroindium phthalocyanines, chlorogallium phthalocyanines, and hydroxygallium phthalocyanines. In addition, among the crystal forms of titanyl phthalocyanine mentioned here, α-form and β-form are described in W.S. Phase II, I by Heller et al.
Phase (Zeit. Kristallogr. 159 (1982) 17
3), β type is known as stable type. The most preferably used Y type is a crystal type characterized in that a diffraction angle 2θ ± 0.2 ° shows a clear peak at 27.3 ° in powder X-ray diffraction using CuKα ray.
The phthalocyanine compound may be a single compound alone, or may be a mixture of several compounds. Here, as the phthalocyanine compound or a mixed state that can be placed in a crystalline state, the respective constituent elements 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, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, Used in a form bound with various binder resins such as cellulose ester and cellulose ether. In this case, the usage ratio of the charge generating substance is usually 20 to 2,000 parts by weight, preferably 30 to 500 parts by weight, more preferably 33 to 500 parts by weight, based on 100 parts by weight of the binder resin.

If necessary, other organic photoconductive compounds, 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.
μm is preferred. The charge transport layer of the electrophotographic photoreceptor is mainly composed of a charge transport material and a binder resin. As the binder resin, the above-mentioned polyester resin is mainly used.

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, 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 these, carbazole derivatives,
A hydrazone derivative, an aromatic amine derivative, a stilbene derivative, a butadiene derivative 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 are particularly preferable.

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 material in the charge transporting layer is usually such that the charge transporting material is used in an amount of 30 to 200 parts by weight, preferably 40 to 150 parts by weight, and most preferably the upper limit. Of 90 parts by weight is advantageous in maintaining the mechanical properties of the polyarylate. The film thickness is generally 10
６０60 μm, preferably 10-45 μm, more preferably 27-40 μm.

In order to improve the film-forming property, flexibility, coating property, stain resistance, gas resistance, light resistance, etc., the charge transport layer includes a well-known plasticizer, antioxidant, ultraviolet absorber, Additives such as an electron-withdrawing compound, a leveling agent, and a sensitizer may be contained. Examples of the electron withdrawing compound include chloranil, 2,3-dichloro-1,4-naphthoquinone,
Quinones such as -nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone and phenanthrenequinone; aldehydes such as 4-nitrobenzaldehyde; 9-benzoylanthracene, indandione, 3,5-dinitrobenzophenone, , 4,
Ketones such as 7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, 3,3 ', 5,5'-tetranitrobenzophenone; acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride A cyano compound such as tetracyanoethylene, terephthalalmalononitrile, 9-anthrylmethylidenemalononitrile, 4-nitrobenzalmalonitrile, 4- (p-nitrobenzoyloxy) benzalmalonitrile; 3-benzalphthalide; 3- (α-cyano-p-nitrobenzal) phthalide, 3- (α-cyano-p-nitrobenzal) -4,
Electron-withdrawing compounds such as phthalides such as 5,6,7-tetrachlorophthalide.

Examples of the antioxidant include a hindered phenol compound and a hindered amine compound. Examples of dyes that may be added to the photosensitive layer of the electrophotographic photoreceptor include, for example, triphenylmethane dyes such as methyl violet, brilliant green, and crystal violet; thiazine dyes such as methylene blue; quinone dyes such as quinizarin; Salts, thiavirilium salts, benzovirylium salts and the like.

The photosensitive layer of the electrophotographic photoreceptor is prepared by dissolving a charge transporting substance in a suitable solvent together with a binder resin containing a polyarylate resin according to a conventional method, and, if necessary, a suitable charge generating substance and a sensitizing dye. A coating solution obtained by adding a known additive such as an electron-withdrawing compound, another charge transporting substance, or a plasticizer or a pigment is coated on a conductive support.
It can be manufactured by drying to form a photosensitive layer. In the case of a photosensitive layer consisting of two layers, a charge generation layer and a charge transport layer, the above-mentioned coating solution is applied on the charge generation layer,
It can be manufactured by forming a charge generation layer on a charge transport layer obtained by applying the above coating solution.

Solvents for preparing a 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 one that dissolves the binder from these.

The photosensitive layer of the electrophotographic photosensitive member 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, phosphoric acid 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-mentioned composition, but the photoconductive particles, the dye, the electron withdrawing compound, etc. may be removed or a small amount may be added. . In this case, the charge generation layer is obtained by dissolving and dispersing in a solvent such as a binder polymer or another organic photoconductive substance, a dye or an electron-withdrawing compound, if necessary, in addition to the photoconductive particles. A thin layer obtained by applying and drying a coating solution to be obtained, or a layer in which the photoconductive particles are formed into a film by means such as vapor deposition.

A protective layer may be provided on the photosensitive layer for the purpose of preventing the photosensitive layer from being worn and preventing or reducing the deterioration of the photosensitive layer due to a discharge product or the like generated from a charger or the like.
Further, for the purpose of reducing frictional resistance and abrasion on the surface of the photoreceptor, the surface layer may contain a fluorine 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. 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.

The spray coating method includes 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 conveying method disclosed in the re-published Japanese Patent Publication No. 1-805198, that is, by continuously conveying the cylindrical work without rotating the axial direction while rotating the cylindrical work, An electrophotographic photoreceptor excellent in uniformity of film thickness with high overall deposition efficiency can be obtained.

The spiral coating method is disclosed in
Japanese Patent Application Laid-Open No. H11-231966 discloses a method using a liquid injection coating machine or a curtain coating machine disclosed in Japanese Patent Application Publication No. 119651.
There is a method disclosed in Japanese Patent Application Laid-Open Publication No. H10-193, in which the coating material is continuously flew from the minute opening in a streak shape, and a method using a multi-nozzle body disclosed in Japanese Patent Application Laid-Open No. 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, etc., 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. The drying temperature and time may be adjusted so that necessary and sufficient drying is performed. The drying temperature is usually 100-250 ° C, preferably 1
The temperature is in the range of 10 to 170C, more preferably 120 to 140C. 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
Since the fluctuation due to repetition is small, and in particular, the charging stability affecting the image density is good, 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.

An electrophotographic apparatus such as a copying machine or a printer using the electrophotographic photosensitive member of the present invention includes at least processes of charging, exposing, developing, and transferring. A method may be used. More specifically, as a charging method (charging device), any one of ordinary methods such as corotron or scorotron charging using corona discharge, and contact charging using a conductive roller or a brush or a film is used. Is also good. Of these, in the charging method using corona discharge, scorotron charging is often used to keep the dark area potential constant. Further, 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. Examples of the transfer method include a method using corona discharge, a method using a transfer roller or a transfer belt, and the like.
Either may be used. As a transfer method, it may be directly performed on paper or an OHP film, 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 on paper or the like is used, and as a fixing means, generally used heat fixing, pressure fixing and the like can be used. In addition to these processes, processes that are generally used, such as cleaning and static elimination, may be provided.

[0056]

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. - Example 1 with H ₂ O (400ml) were weighed sodium hydroxide 1L beaker Production of Polyester Resin (A)] (5.21g), were stirred and dissolved with a nitrogen bubbling. There, p-tert-butylphenol (0.2179)
g), benzyltriethylammonium chloride (0.0639 g), 2,2-bis- (4-hydroxyphenyl) propane [BPA] (5.72 g) and 3-
[1- (4-Hydroxyphenyl) -1-methylethyl] phenol [3,4'-BPA] (5.72 g) was added in that order, and the mixture was stirred, and then the alkaline aqueous solution was transferred to a 2 L reaction tank.

Separately, isophthalic acid [IPA] chloride (10.37 g) was 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 (1.72 ml),
Dichloromethane (160 ml) and water (80 ml) were added and stirred for 30 minutes. Thereafter, the stirring was stopped and the organic layer was separated. The organic layer was washed with a 0.1N aqueous sodium hydroxide solution (307 ml), then twice with 0.1N hydrochloric acid (307 ml), and further washed with H ₂ O (3 ml).
07 ml).

360 ml of methylene chloride was added to the washed organic layer.
Was added, and the mixture was poured into methanol (1800 ml), and the resulting precipitate was filtered out and dried to obtain the desired polyester resin (A). The viscosity average molecular weight of the obtained polyester resin (A) was about 19,500.
The structural formula of the obtained polyester resin (A) is shown below.

Embedded image a / b = 5/5 ... polyester resin (A)

[Measurement of Viscosity Average Molecular Weight] A polyester resin was dissolved in dichloromethane, and the concentration C was 6.00 g / L.
Was prepared. Using a Ubbelohde capillary viscometer with a flow time t ₀ of the solvent (dichloromethane) of 136.16 seconds, the flow time t of the sample solution was measured in a thermostatic water bath set at 20.0 ° C. The viscosity average molecular weight Mv was calculated according to the following equation. 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 of photoreceptor] (Production of charge generation layer) 10 parts by weight of β-type oxytitanium phthalocyanine [1] having the following structure was added to 150 parts by weight of 4-methoxy-4-methylpentanone-2.
Pulverization and dispersion treatment was performed with a sand grind mill.

Embedded image ... β-type oxytitanium phthalocyanine [1] Further, polyvinyl butyral (manufactured by Denki Kagaku Kogyo KK,
5% of brand name Denka Butyral # 6000C) 1,2
-100 parts of dimethoxyethane solution and 5% of phenoxy resin (PKHH, manufactured by Union Carbide Co.)
A binder solution was prepared by mixing 100 parts of a 1,2-dimethoxyethane solution.

To 160 parts by weight of the previously prepared pigment dispersion,
100 parts by weight of the binder solution and an appropriate amount of 1,2-dimethoxyethane were added to finally prepare a dispersion having a solid content 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, 60 parts of the following charge transport material [1]

Embedded image ... 100 parts of the charge transport material [1] and the polyester resin (A), and 0.03 part of a silicone oil as a leveling agent in 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] A toner prepared by cutting a urethane rubber of the same material as the cleaning blade to a width of 1 cm on the surface to which the toner is uniformly placed so as to have a concentration of 0.1 mg / cm 2 on the photoreceptor prepared above and brought into contact therewith. Used at 45 degree angle, load 200g, speed 5mm / sec, stroke 2
10 when urethane rubber is moved 100 times at 0 mm
The 0th dynamic friction coefficient was measured with a fully automatic friction and wear tester DFPM-SS manufactured by Kyowa Interface Chemical Co., Ltd. The results are shown in Table 1 below.

[Abrasion test] A photoreceptor film having a diameter of 10c was used.
m and cut into a circle, and the wear was evaluated using a Taber abrasion tester (manufactured by Toyo Seiki Co., Ltd.). The test conditions were 23 ° C,
Under an atmosphere of 50% RH, using a worn wheel CS-10F,
The amount of wear after 1000 rotations without a load (the weight of the worn wheel) was measured by comparing the weight before and after the test. The results are shown in Table 1 below.

Example 2 [Production of Polyester Resin (B)] Sodium hydroxide (7.82 g) and H ₂ O (600 ml) were weighed into a 1 L beaker, and stirred and dissolved while bubbling with nitrogen. This was added with p-tert-butylphenol (0.3269)
g), benzyltriethylammonium chloride (0.0959 g), 2,2-bis- (4-hydroxyphenyl) propane [BPA] (8.58 g) and 3-
[1- (4-Hydroxyphenyl) -1-methylethyl] phenol [3,4'-BPA] (8.58 g) was added in that order, and the mixture was stirred, and then the alkaline aqueous solution was transferred to a 2 L reaction tank.

Separately, terephthalic acid [TPA] chloride (15.56 g) was dissolved in dichloromethane (300 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 (2.58 ml),
Dichloromethane (240 ml) and water (120 ml) were added and stirred for 30 minutes. Thereafter, the stirring was stopped and the organic layer was separated. This organic layer was washed with a 0.1N aqueous sodium hydroxide solution (460 ml), and then washed with 0.1N hydrochloric acid (4 ml).
60 ml), and further washed with H ₂ O (460 ml).
ml) twice.

540 ml of methylene chloride was added to the washed organic layer.
Was added, and the mixture was poured into methanol (2700 ml), and the resulting precipitate was taken out by filtration and dried to obtain the desired polyester resin (A). The viscosity average molecular weight of the obtained polyester resin (B) was 30,800. The structural formula of the obtained polyester resin (B) is shown below.

Embedded image a / b = 5/5 ... polyester resin (B)

[Test and Evaluation for Photoconductor Using Polyester Resin (B)] A photoconductor was manufactured in the same manner as in Example 1 using the polyester resin (B). At this time, the solubility of the polyester resin was good. A friction test, an abrasion 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. The results are shown in Table 1 below.

Comparative Example 1 [Production of Polyester Resin (C)] Sodium hydroxide (5.84 g) and H ₂ O (400 ml) were weighed into a 1 L beaker, and stirred and dissolved while bubbling with nitrogen. To this, p-tert-butylphenol (0.2179)
g), benzyltriethylammonium chloride (0.0639 g), 2,2-bis- (4-hydroxyphenyl) propane [BPA] (12.83 g) were added in this order, and the mixture was stirred. Moved.

Separately, terephthalic acid [TPA] chloride (10.37 g) was 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 (2.62 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. This organic layer was washed with a 0.1N aqueous sodium hydroxide solution (4
50 ml), and then 0.1N hydrochloric acid (450 ml).
was washed twice with H ₂ O (450 m
Washing was performed twice in 1).

540 ml of methylene chloride was added to the washed organic layer.
Was added, and the mixture was poured into methanol (2700 ml), and the resulting precipitate was taken out by filtration and dried to obtain the desired polyester resin (C). The obtained polyester resin (C) became insoluble in methylene chloride, and the viscosity could not be measured. The structural formula of the obtained polyester resin (C) is shown below.

Embedded image ... Polyester resin (C)

[Evaluation of Polyester Resin (C)] The polyester resin (C) was insoluble in a mixed solvent of THF / toluene (8/2 weight ratio). Comparative Example 2 [Production of Polyester Resin (D)] Sodium hydroxide (2.15 g) and H ₂ O (200 ml) were weighed into a 1 L beaker, and dissolved by stirring while bubbling with nitrogen. This was added with p-tert-butylphenol (0.089
g), benzyltriethylammonium chloride (0.0264 g), 2,2-bis- (4-hydroxyphenyl) propane [BPA] (2.36 g) and 3-
[1- (4-Hydroxyphenyl) -1-methylethyl] phenol [3,4'-BPA] (2.36 g) was added in that order, and the mixture was stirred, and then the alkaline aqueous solution was transferred to a 2 L reaction vessel. Separately, 4,4'-biphenyldicarboxylic acid [Bp] chloride (5.88 g) was dissolved in dichloromethane (100 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 stirring was further continued for 3 hours, acetic acid (0.71 ml), dichloromethane (80 ml) and water (40 ml) were added, and the mixture was stirred for 30 minutes.
Thereafter, the stirring was stopped and the organic layer was separated. This organic layer is washed with a 0.1 N aqueous sodium hydroxide solution (153 ml), then twice with 0.1 N hydrochloric acid (153 ml), and twice with H ₂ O (153 ml). Done.

After washing, 180 ml of methylene chloride was added to the organic layer.
Was added, and the mixture was poured into methanol (900 ml), and the obtained precipitate was taken out by filtration and dried to obtain a target polyester resin (D). The viscosity average molecular weight of the obtained polyester resin (D) was 9,200. The structural formula of the obtained polyester resin (D) is shown below.

Embedded image a / b = 5/5 polyester resin (D) [Evaluation of polyester resin (D)] The polyester resin (D) was insoluble in a mixed solvent of THF / toluene (8/2 weight ratio).

Comparative Example 3 [Production of Photoconductor Using Polycarbonate Resin (E)]
Same as Example 1 except that 100 parts of the polyester resin in [Production of photoconductor] (Production of charge transport layer) of Example 1 was changed to 100 parts of polycarbonate resin (E) having the following structure. A photoreceptor was prepared.

Embedded image a / b = 5/5 Polycarbonate resin (E) [Test and evaluation on photoconductor using polycarbonate resin (E)] A friction test, an abrasion test and an evaluation of electrical properties of the obtained photoconductor were performed in Examples. The same procedure as in Example 1 was performed under the same conditions. Table 1 shows the results.

[Table 1] 1) Tetrahydrofuran / toluene = 80/20 (weight ratio)
2) Viscosity average molecular weight 3) Taber abrasion test 4) Dynamic coefficient of friction From the above results, the polyester resin of the present invention exhibits excellent abrasion resistance and slipperiness, and is coated on the charge transport layer of the electrophotographic photosensitive member. It turns out that it is excellent in solubility in a solvent.

[0076]

The polyester resin having a specific structure of the present invention exhibits excellent abrasion resistance and slipperiness,
Since it has excellent solubility in organic solvents, it can be suitably used as a binder resin for an electrophotographic photoreceptor. In addition, by using the polyester resin of the present invention as a binder resin, while having excellent durability,
It is possible to obtain an electrophotographic photoreceptor capable of coping with high image quality.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Shosho Fujii 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsubishi Chemical Research Institute (72) Inventor Ringo 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Mitsubishi Chemical Corporation Yokohama Research Laboratory F-term (reference) 2H068 AA13 AA21 BB20 BB27 BB52 FA03 FA04 4J029 AA03 AB01 AB07 AC01 AC02 AD01 AE11 BA02 BA03 BA05 BA08 BB04A BB05A BB12A BB12B BB12C BB13A BB13B02A03 CA05 CA06 CB04A CB05A CB06A CB10A CC05A DB07 DB13 GA13 GA14 KB02

Claims (8)

[Claims] 1. A polyester resin comprising a repeating unit represented by the following general formula (1) in the structural formula, and having a viscosity average molecular weight of 10,000 to 200,000. Embedded image ... In the general formula (1), (In the general formula (1), R _{1 to} R ₈ each independently represent a hydrogen atom or a substituent. X represents a single bond or a divalent linking group; Y represents 2 Represents a valent organic linking group.) 2. The polyester resin according to claim 1, wherein the content of the repeating unit represented by the general formula (1) is 1 to 100% by weight based on all the repeating units constituting the polyester resin. . 3. The copolymer component other than the repeating unit of the general formula (1), wherein the structural formula includes a repeating unit represented by the following general formula (2). Item 3. The polyester resin according to Item 2. Embedded image In ... formula (2) (formula (2), R _'1 to R' ₈ each independently represent a hydrogen atom or a substituent. Also, X 'represents a single bond or a divalent linking group, Y ′ represents a divalent organic linking group.) 4. The polyester resin according to claim 1, wherein X is an alkylene group in the general formula (1). 5. The polyester resin according to claim 1, wherein in the general formula (1), Y is a divalent aromatic group. 6. The polyester resin according to claim 1, having a viscosity average molecular weight of 15,000 to 100,000. 7. The method according to claim 1, wherein the repeating unit of the general formula (1) is represented by the following chemical formula (1).
7. The polyester resin according to any one of items 6 to 6. Embedded image ... Chemical formula (1) 8. An electrophotographic photoreceptor having at least a photosensitive layer on a conductive support, wherein the photosensitive layer is formed on the conductive support.
An electrophotographic photosensitive member, comprising the polyester resin according to any one of the above.