JP4487997B2 - Electrophotographic photoreceptor - Google Patents

Description

  The present invention relates to a resin for an electrophotographic photoreceptor. More specifically, the present invention relates to a resin for an electrophotographic photosensitive member having a specific chemical structure, excellent wear resistance, surface slipperiness, life of a coating solution, and the like, and having good electrical response.

  Since the electrophotographic photosensitive member is repeatedly used in an electrophotographic process, that is, a cycle of charging, exposure, development, transfer, cleaning, static elimination, and the like, it is deteriorated by various stresses during that time. Such deterioration includes, for example, strongly oxidative ozone and NOx generated from a corona charger that is normally used as a charger, which gives chemical damage to the photosensitive layer, or a carrier (current) generated by image exposure. Is chemically and electrically deteriorated due to the fact that the composition of the photosensitive layer decomposes due to flowing in the photosensitive layer, static elimination light, or external light. In addition, there are mechanical deteriorations such as abrasion of the photosensitive layer surface due to rubbing of a cleaning blade, a magnetic brush or the like, contact with a developer, paper, etc., scratches, and film peeling. In particular, the damage generated on the surface of the photosensitive layer is likely to appear on the copy image, which directly impairs the image quality and is a major factor that limits the life of the photoreceptor. That is, in order to develop a long-life photoconductor, it is essential to increase the mechanical strength as well as the electrical and chemical durability.

  In general, a charge transfer layer is subjected to such a load in the case of a laminated type photoreceptor. The charge transfer layer is usually composed of a binder resin and a charge transfer material, and it is the binder resin that substantially determines the strength. However, since the amount of the charge transfer material doped is considerably large, sufficient mechanical strength has been reached. Not in. In addition, due to the increasing demand for high-speed printing, materials for a higher-speed electrophotographic process are required. In this case, in addition to high sensitivity and long life, the photosensitive member must have good responsiveness because the time from exposure to development is shortened. It is known that the responsiveness of the photoreceptor is governed by the charge transfer layer, particularly the charge transfer substance, but also greatly changes depending on the binder resin.

  Conventionally, as the binder resin of the charge transfer layer, vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resins, Various thermosetting resins have been used. Among the various binder resins, the polycarbonate resin has relatively excellent performance, and various polycarbonate resins have been developed and put into practical use.

  For example, Patent Document 1 discloses a bisphenol P type polycarbonate, Patent Document 2 discloses a bisphenol Z type polycarbonate, Patent Document 3 discloses a copolymer type polycarbonate of bisphenol P and bisphenol A, and Patent Document 4 discloses a bis ( Polycarbonate copolymers containing a 4-hydroxyphenyl) ketone type structure are each disclosed as a binder resin. However, conventional organic photoreceptors have drawbacks such as surface wear and scratches caused by practical loads such as development with toner, friction with paper, and friction with a cleaning member (blade). Therefore, the current situation is that the printing performance is limited in practical use.

  On the other hand, Patent Document 5 discloses a technique of an electrophotographic photoreceptor using a polyarylate (aromatic polyester) resin marketed under the trade name “U-polymer” as a binder, and compared with polycarbonate. It is shown that the sensitivity is particularly excellent. Patent Document 6 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.

  Patent Document 7 discloses an electrophotographic photosensitive member characterized by containing a mixture of polycarbonate and polyarylate as a binder resin using a bisazo pigment having a specific structure as a charge generating material, a diamine compound having a specific structure as a charge transporting material, and a binder resin. It is shown. However, when the currently used polycarbonate resin is used in the electrophotographic process, it is still often insufficient in terms of abrasion resistance, scratch resistance, responsiveness, adhesion to the substrate, and the like.

  In addition, although the commercially available polyarylate resin “U-polymer” shows some improvement in wear resistance and sensitivity, the coating solution is not stable and coating production is impossible or the slipping property is poor. It was. In addition, when a polyarylate (aromatic polyester) copolymer having a structure using tetramethylbisphenol F and bisphenol A is used as the bisphenol component disclosed in Patent Document 6, compared to conventional polycarbonate in terms of wear resistance. However, superiority is not recognized in terms of slipperiness compared to polycarbonate, and performance is significantly inferior to polycarbonate in terms of electrical characteristics, particularly sensitivity and responsiveness.

In addition, as disclosed in Patent Document 7, when polyarylate and polycarbonate are mixed and used as a binder resin, the content of polyarylate is as low as 30% by weight or less, so that it is conventional in terms of mechanical properties such as slipperiness. A sufficient improvement effect was not obtained as compared with the case of using this binder resin. Therefore, the present situation is that a binder resin excellent in wear resistance and slipperiness is desired while maintaining excellent electrical characteristics such as responsiveness.
JP 50-98332 A JP 59-71057 A JP 59-184251 JP-A-5-21478 JP-A-56-135844 Japanese Patent Laid-Open No. 3-6567 Japanese Patent Laid-Open No. 7-128884

  An object of the present invention is to solve the above-mentioned problems and to provide an electrophotographic photoreceptor excellent in wear resistance and slipperiness.

  As a result of detailed studies on the binder resin used in the photosensitive layer, the present inventors have obtained sufficient mechanical properties by using a polyarylate resin having a specific structure as the binder resin, and are highly soluble in non-halogen solvents. As a result, the inventors have found that the stability of the coating property / coating liquid is improved and that the electrical characteristics, particularly the responsiveness, are excellent, and the present invention has been achieved.

  Since conventional polyarylate resin is inferior to polycarbonate resin in terms of electrical characteristics, practical performance can be obtained except that a small amount of polyarylate resin is blended with polycarbonate resin as exemplified in Patent Document 7, for example. There wasn't. However, since the polyarylate resin of the present invention greatly improves electrical characteristics and is excellent in mechanical strength, the polyarylate resin of the present invention is excellent in slipperiness by mixing in a high ratio or using alone. A practical electrophotographic photosensitive member could be obtained.

That is, the gist of the present invention is that in an electrophotographic photoreceptor having at least a photosensitive layer on a conductive substrate, the binder resin of the photosensitive layer is a structural unit represented by the following general formula (1) and general formula (2). A polyarylate resin obtained by an interfacial polymerization method, wherein n / (n + m)> 0.9 , and the polyarylate resin exceeds 30% by weight in the total binder resin. It exists in a photographic photoreceptor.

(In the general formula (1), R ^{1 to} R ⁸ each independently represents a hydrogen atom or an optionally substituted alkyl group, and Z represents a divalent linking group, provided that at least ^{one of} R ^{1 to} R ⁸ One is an alkyl group which may be substituted, and in general formula (2), Y and Z represent a divalent linking group, and general formula (2) represents a structure different from general formula (1). .)

  The polyarylate resin having a specific structure according to the present invention has high solubility in non-halogen solvents / stability of coating solution, and by using this resin, electrical properties are good and mechanical strength and slippage are improved. An electrophotographic photoreceptor excellent in properties can be obtained.

  The present invention will be described in detail below. The electrophotographic photoreceptor of the present invention is characterized in that at least a photosensitive layer is provided on a conductive support, and a specific arylate resin described below is used for the photosensitive layer.

  As the conductive support, for example, a metal material such as aluminum, aluminum alloy, stainless steel, copper, nickel or the like, a resin material or aluminum provided with conductivity by adding conductive powder such as metal, carbon, tin oxide, Mainly used are resin, glass, paper, or the like, on which a conductive material such as nickel or ITO (indium tin oxide alloy) is deposited or coated. As a 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 coated on a conductive support made of a metal material in order to control conductivity and surface properties or to cover defects.

  When a metal material such as an aluminum alloy is used as the conductive support, it may be used after anodizing, chemical conversion coating or the like. When the anodizing treatment is performed, it is desirable to perform a 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, it 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 metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. Only one type of particle may be used, 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 thing of a several crystalline state may be contained.

  In addition, various particle diameters of the metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle diameter is preferably 10 nm or more and 100 nm or less, and particularly preferably 10 nm or more. 25 nm or less. The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As binder resin used for the undercoat layer, phenoxy, epoxy, polyvinyl pyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. are used alone or in a cured form together with a curing agent. Among them, alcohol-soluble copolymerized polyamides, modified polyamides and the like are preferable because they exhibit good dispersibility and coating properties.

  In the undercoat layer, the addition ratio of the inorganic particles to the binder resin can be arbitrarily selected, but it is preferably used in the range of 10 to 500% by weight in terms of the stability of the dispersion and the coating property. The thickness of the undercoat layer can be arbitrarily selected, but is preferably 0.1 μm to 20 μm from the viewpoint of photoreceptor characteristics and applicability. Moreover, you may add a well-known antioxidant etc. to an undercoat layer.

Specific examples of the photosensitive layer used in the present invention include the following.
1) A laminated photosensitive layer in which a charge generation layer mainly composed of a charge generation material, a charge transport material and a charge transport layer mainly composed of a binder resin are laminated in this order on a conductive support.
2) A reverse two-layer type photosensitive layer in which a charge transport layer mainly composed of a charge transport material and a binder resin and a charge generation layer composed mainly of a charge generation material are laminated in this order on a conductive support.
3) A dispersion type photosensitive layer (single layer photosensitive layer) in which a charge generating material is dispersed in a layer containing a charge transporting material and a binder resin on a conductive support.

  Of these, a laminated photosensitive layer is preferred. In the case of a laminated photosensitive layer, the arylate resin shown below is used as a binder resin for a charge transfer layer. In the case of a multilayer photoreceptor, charge generation materials used in the charge generation layer include, for example, selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments, azo pigments, quinacridone pigments, indigo pigments, perylene pigments. Various photoconductive materials such as organic pigments such as polycyclic quinone pigments, anthanthrone pigments and benzimidazole pigments can be used, and organic pigments, phthalocyanine pigments and azo pigments are particularly preferable. These fine particles are, for example, polyester resin, polyvinyl acetate, polyacrylate ester, polymethacrylate ester, polyester, polycarbonate, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, cellulose ester, cellulose ether. It is used in a form bound with various binder resins. The use ratio in this case is used in the range of 30 to 500 parts by weight with respect to 100 parts by weight of the binder resin, and the film thickness is usually 0.1 μm to 1 μm, preferably 0.15 μm to 0.6 μm.

  When a phthalocyanine compound is used as the charge generation material, specifically, a metal such as metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or an oxide or halide thereof. Phthalocyanines are used. Examples of the ligand to a metal atom having 3 or more valences include a hydroxyl group and an alkoxy group in addition to the oxygen atom and chlorine atom shown above. Particularly preferred are X-type, τ-type metal-free phthalocyanine, α-type, β-type, Y-type oxytitanyl phthalocyanine, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, and the like.

  Of the crystal forms of oxytitanium phthalocyanine, the β type and α type are described in W.W. It has been shown by Heller et al. As phase I and phase II, respectively (Zeit. Kristallogr. 159 (1982) 173), and the β form is known as a stable form. The Y type is a crystal type characterized by a clear peak at a diffraction angle 2θ ± 0.2 ° of 27.3 ° in powder X-ray diffraction using CuKα rays. In addition, diffraction peaks are usually shown at 7.4 °, 9.7 °, and 24.2 °. As the charge generating substance, α-type, β-type, Y-type, or oxytitanium phthalocyanine mixed with these is preferably used in terms of sensitivity.

  As the phthalocyanine compound, only a single compound may be used, or several mixed states may be used. As the mixed state that can be placed in the phthalocyanine compound or crystal state here, the respective constituent elements may be mixed and used later, or the mixed state in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, crystallization, etc. It may be generated. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known.

  Examples of the charge transport material contained in the charge transport layer include aromatic acceptor substances such as aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, and quinones such as diphenoquinone, Carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, oxadiazole derivatives, pyrazoline derivatives, thiadiazole derivatives and other heterocyclic compounds, aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine compounds And an electron-donating substance such as a polymer in which a plurality of these compounds are bonded, or a polymer having a group composed of these compounds in the main chain or side chain.

  Among these, a carbazole derivative, a hydrazone derivative, an aromatic amine derivative, a stilbene derivative, a butadiene derivative, and a combination of these derivatives are preferable, and an aromatic amine derivative, a stilbene derivative, and a combination of butadiene derivatives are further combined. preferable. Moreover, it is particularly preferable to use an aromatic amine compound represented by the following general formula (3).

(In General Formula (3), Ar ^{1 to} Ar ⁴ each independently represent an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent. Ar ⁵ and Ar ⁶ may each have an alkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent when m1 = 0 and m2 = 0. Represents a good monovalent heterocyclic group. When m1 = 1 and m2 = 1, each has an alkylene group which may have a substituent, an arylene group which may have a substituent, or a substituent. Represents a divalent heterocyclic group which may optionally be substituted, Q represents a direct bond or a divalent residue, and R ^{9 to} R ¹⁶ each independently represents a hydrogen atom or an optionally substituted alkyl. Group, aryl group optionally having substituent, aralkyl group optionally having substituent, heterocyclic ring optionally having substituent Each independently is .n1~n4 representing a represents an integer of 0 to 4. Also, m1, m @ 2 each independently represents 0 or 1. Also a ring structure by bonding with Ar ¹ to Ar ⁶ each other It may be formed.)

In general formula (3), R ^{9 to} R ¹⁶ each independently have a hydrogen atom, an alkyl group that may have a substituent, an aryl group that may have a substituent, or a substituent. Represents an aralkyl group which may be substituted, or a heterocyclic group which may have a substituent. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, a hexyl group, A heptyl group, a cyclopentyl group, a cyclohexyl group, etc. are mentioned, Among these, a C1-C6 alkyl group is preferable.

Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a pyrenyl group, and an aryl group having 6 to 12 carbon atoms is preferable. Examples of the aralkyl group include a benzyl group and a phenethyl group, and an aralkyl group having 7 to 12 carbon atoms is preferable. The heterocyclic group is preferably an aromatic heterocyclic ring, and examples thereof include a furyl group, a thienyl group, and a pyridyl group, and a monocyclic aromatic heterocyclic ring is more preferable. In R ^{9 to} R ¹⁶ , the most preferred are a methyl group and a phenyl group.

In general formula (3), Ar ^{1 to} Ar ⁴ each independently represents an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent, Ar ⁵ and Ar ⁶ each have an alkyl group which may have a substituent, an aryl group which may have a substituent, and a substituent when m1 = 0 and m2 = 0. Represents a monovalent heterocyclic group, and when m1 = 1 and m2 = 1, an alkylene group which may have a substituent, an arylene group or a substituent which may have a substituent, respectively. The aryl group may be a divalent heterocyclic group which may have a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a pyrenyl group, etc., and an aryl group having 6 to 14 carbon atoms is preferred. The arylene group includes a phenylene group, a naphthylene group, and the like. The monovalent heterocyclic group is preferably an aromatic heterocyclic ring, and examples thereof include a furyl group, a thienyl group, and a pyridyl group, and a monocyclic aromatic heterocyclic ring is more preferable; As the heterocyclic group, an aromatic heterocyclic ring is preferable, and examples thereof include a pyridylene group and a thienylene group, and a monocyclic aromatic heterocyclic ring is more preferable. Of these, the most preferable ones are Ar ¹ and Ar ² are phenylene groups, and Ar ³ is a phenyl group.

Of these groups represented by R ^{9 to} R ¹⁶ and Ar ^{1 to} Ar ⁶ , the alkyl group, aryl group, aralkyl group, and heterocyclic group may further have a substituent. Cyano group; nitro group; hydroxyl group; halogen atom such as fluorine atom, chlorine atom, bromine atom, iodine atom; methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t- Alkyl groups such as butyl group, pentyl group, hexyl group, cyclopentyl group, cyclohexyl group; alkoxy groups such as methoxy group, ethoxy group, propyloxy group; alkylthio groups such as methylthio group, ethylthio group; vinyl groups, allyl groups, etc. Alkenyl group; aralkyl group such as benzyl group, naphthylmethyl group and phenethyl group; aryloxy group such as phenoxy group and triloxy group; Aryloxy groups such as oxy group and phenethyloxy group; aryl groups such as phenyl group and naphthyl group; aryl vinyl groups such as styryl group and naphthyl vinyl group; acyl groups such as acetyl group and benzoyl group; dimethylamino group and diethylamino group Dialkylamino groups such as diphenylamino groups and dinaphthylamino groups; diaralkylamino groups such as dibenzylamino groups and diphenethylamino groups; diheterocyclic amino groups such as dipyridylamino groups and dithienylamino groups; Groups: diallylamino groups, and substituted amino groups such as di-substituted amino groups obtained by combining substituents of the above amino groups.

  These substituents may be bonded to each other to form a cyclic hydrocarbon group or a heterocyclic group via a single bond, a methylene group, an ethylene group, a carbonyl group, a vinylidene group, an ethylenylene group or the like.

  Among these, preferred substituents are halogen atoms, cyano groups, hydroxyl groups, alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, alkylthio groups having 1 to 6 carbon atoms, and 6 to 12 carbon atoms. An aryloxy group, an arylthio group having 6 to 12 carbon atoms, and a dialkylamino group having 2 to 8 carbon atoms are exemplified. A halogen atom, an alkyl group having 1 to 6 carbon atoms, and a phenyl group are more preferable, and a methyl group and a phenyl group are preferable. Particularly preferred.

  In general formula (3), n1 to n4 each independently represents an integer of 0 to 4, preferably 0 to 2, and most preferably 1. m1 and m2 represent 0 or 1, with 0 being preferred. In general formula (3), Q represents a direct bond or a divalent residue, but preferred as the divalent residue is a group 16 atom, an alkylene which may have a substituent, or a substituent. An arylene group which may be substituted, a cycloalkylidene group which may have a substituent, or a group in which these are bonded to each other, for example, [—O—A—O—], [—A—O—A—], [—S -AS-], [-AA-], etc. (in which A represents an arylene group which may have a substituent or an alkylene group which may have a substituent).

  As an alkylene group which comprises Q, a C1-C6 thing is preferable and a methylene group and an ethylene group are still more preferable especially. Moreover, as a cycloalkylidene group, a C5-C8 thing is preferable and a cyclopentylidene group and a cyclohexylidene group are still more preferable especially. As the arylene group, those having 6 to 14 carbon atoms are preferable, and among them, a phenylene group and a naphthylene group are more preferable.

  These alkylene groups, arylene groups, and cycloalkylidene groups may have a substituent. Preferred substituents include a hydroxyl group, a nitro group, a cyano group, a halogen atom, an alkyl group having 1 to 6 carbon atoms, carbon A C1-C6 alkenyl group and a C6-C14 aryl group are mentioned.

  These charge transport materials may be used alone or in combination. The charge transport layer is formed in such a form that these charge transport materials are bound to the binder resin. The charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different constituent components or composition ratios.

  In the charge transport layer, the ratio of the binder resin to the charge transport material is usually 30 to 200 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. The film thickness is generally 5 to 50 μm, preferably 10 to 45 μm. For the charge transport layer, well-known plasticizers, antioxidants, ultraviolet absorbers, electron-accepting compounds are used to improve film-forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc. Further, additives such as a leveling agent may be contained. Examples of the antioxidant include hindered phenol compounds and hindered amine compounds.

  In the case of a dispersion-type photosensitive layer, the above-described charge generating material is dispersed in the charge transport medium having the above-described blending ratio. In this case, the particle size of the charge generating material needs to be sufficiently small, and is preferably 1 μm or less, more preferably 0.5 μm or less. If the amount of the charge generating material dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained, and if it is too large, there are adverse effects such as reduced chargeability and reduced sensitivity, for example, preferably 0.5 to 50 weights. %, More preferably 1 to 20% by weight.

  The film thickness of the photosensitive layer in the case of the dispersion type photosensitive layer is usually 5 to 50 μm, more preferably 10 to 45 μm. Also in this case, known plasticizers for improving film formability, flexibility, mechanical strength, additives for suppressing residual potential, dispersion aids for improving dispersion stability, coatability Leveling agents and surfactants such as silicone oil, fluorine oil and other additives may be added to improve the viscosity. A protective layer may be provided on the photosensitive layer for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to a discharge product generated from a charger or the like. Further, for the purpose of reducing frictional resistance and wear on the surface of the photoreceptor, the surface layer may contain a fluorine-based resin, a silicone resin, or the like. Moreover, the particle | grains which consist of these resin, and the particle | grains of an inorganic compound may be included.

  Each layer constituting these photoreceptors is formed on the support by dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating or the like. As a method for forming each layer, a known method such as sequentially applying a coating solution obtained by dissolving or dispersing a substance contained in a layer in a solvent can be applied.

  An electrophotographic apparatus such as a copying machine or a printer using the electrophotographic photosensitive member of the present invention includes at least each process of charging, exposure, development, and transfer, and any process that is usually used may be used. . As a charging method (charger), for example, corotron or scorotron charging using corona discharge, contact charging with a conductive roller, brush, film or the like may be used. Of these, scorotron charging is often used in charging methods using corona discharge in order to keep the dark potential constant.

  As a developing method, a general method of developing by bringing a magnetic or non-magnetic one-component developer or two-component developer into contact or non-contact is used. As a transfer method, any method using a corona discharge, a method using a transfer roller or a transfer belt may be used. The transfer may be performed directly on paper, an OHP film, or the like, or may be transferred to an intermediate transfer body (belt shape or drum shape) and then transferred onto paper or an OHP film.

  Usually, after the transfer, a fixing process for fixing the developer onto paper or the like is used, and as the fixing means, commonly used thermal fixing, pressure fixing, or the like can be used. In addition to these processes, processes such as normally used cleaning and static elimination may be provided.

  Next, the polyarylate resin used in the present invention will be described. The arylate resin used in the present invention includes structural units represented by the following general formula (1) and general formula (2), and n / (m + n)> 0.5. It is characterized by exceeding 30% by weight in the resin.

(In the general formula (1), R ^{1 to} R ⁸ each independently represents a hydrogen atom or an optionally substituted alkyl group, and Z represents a divalent linking group, provided that at least ^{one of} R ^{1 to} R ⁸ One is an alkyl group which may be substituted, and in general formula (2), Y and Z represent a divalent linking group, and general formula (2) represents a structure different from general formula (1). .)
N in the general formula (1) and m in the general formula (2) are in the range of 0.5 <n / (m + n) ≦ 1, preferably in the range of 0.75 <n / (m + n) ≦ 1, Preferably, it is in the range of 0.9 <n / (m + n) ≦ 1. When the value of n / (m + n) is 0.5 or less, the electrical characteristics, particularly the responsiveness, when the photosensitive member is used is lowered, and the surface slipping property is further deteriorated, which is not preferable.

In general formula (1), R ^{1 to} R ⁸ each independently represents a hydrogen atom or an optionally substituted alkyl group. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, An alkyl group having 1 to 4 carbon atoms such as an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and a cyclobutyl group is preferable. Examples of these substituents include halogens such as a fluorine atom and a chlorine atom. Examples thereof include an atom, a cyano group, an alkoxy group having 1 to 4 carbon atoms, and an alkylthio group having 1 to 4 carbon atoms, and an unsubstituted alkyl group is preferable. Of these, a methyl group and an ethyl group are more preferable, and a methyl group is most preferable.

At least one of R ^{1 to} R ^{8 is} an optionally substituted alkyl group, but the optionally substituted alkyl group is preferably 2 to 4 of R ^{1 to} R ⁸ , and more preferably 4 of them. Is more preferable.

Z represents a divalent linking group. Examples of the linking group include a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms and a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms. preferably a phenylene group, naphthylene group, biphenylene _{group, - (CH 2) n- (} n = 1~10), - a CH = CH-, particularly preferably a phenylene group, -CH = CH- is used. Further, when Z is a phenylene group, it means that the dicarboxylic acid structural unit constituting the polyarylate resin is phthalic acid and its isomer, and in this case, it may be composed of two or more kinds of carboxylic acid structural units. It is preferable from the viewpoint of solubility. More specifically, it is preferable to have both terephthalic acid and isophthalic acid as carboxylic acid structural units.

  Y in the general formula (2) represents a divalent linking group, and thus represents a dihydroxy structural unit used in the polyarylate resin, which has a structure different from the dihydroxy structural unit in the general formula (1). It is what has.

  An interfacial polymerization method is used as a method for producing the polyarylate resin used in the present invention. In the case of production by the interfacial polymerization method, one or more types of bifunctional phenol components, bisphenol components, and diol components (compounds that derive the dihydroxy structural unit of general formula (1) or general formula (2)) are dissolved in an alkaline aqueous solution. And the halogenated hydrocarbon solution in which one or more kinds of aromatic dicarboxylic acid chloride components (compounds deriving the dicarboxylic acid structural units of the general formulas (1) and (2)) are dissolved are mixed.

  At this time, a quaternary ammonium salt or a quaternary phosphonium salt may be present as a catalyst. The polymerization temperature is preferably 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 water phase and the organic phase are separated, and the polymer dissolved in the organic phase is washed and recovered by a known method, whereby the intended resin can be obtained.

  Examples of the alkali component used here include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide. As the usage-amount of an alkali, the range of 1.0-3 times equivalent of the phenolic hydroxyl group contained in a reaction system is preferable. Examples of the halogenated hydrocarbon used here include dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, dichlorobenzene, and the like.

  The quaternary ammonium salt or quaternary phosphonium salt used as a catalyst includes salts of tertiary alkylamines such as tributylamine and trioctylamine such as hydrochloric acid, bromic acid, 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.

  Among the bisphenol components, preferred specific examples of the compound that derives the dihydroxy structural unit of the general formula (1) include bis- (4-hydroxy-3,5-dimethylphenyl) methane (Tmf), bis- (4-hydroxy -2,5-dimethylphenyl) methane (Xf), bis- (4-hydroxy-2-methylphenyl) methane, bis- (4-hydroxy-3-methylphenyl) methane.

  As aromatic dihydroxy compounds for deriving the dihydroxy structural unit in the general formula (2), hydroquinone, resorcinol, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxy Naphthalene, 2,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, bis- (4-hydroxyphenyl) methane (BPF), bis- (2-hydroxyphenyl) methane, (2-hydroxy Phenyl) (4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) 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), 1,1-bis- (4-hydro) Ci-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-butylphenyl) propane, 1,1-bis- (4-hydroxy-) 3,5-dimethylphenyl) ethane (Xe), 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane (Tma), 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′-dihydroxy Diphenylsulfone, 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, preferred compounds are 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), 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), 1,1-bis- (4-hydroxy-3,5- Dimethylphenyl) ethane (Xe), 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane (Tma), 1,1-bis- (4-hydroxypheny) ) -1-phenylethane (BPP) and the like.

  Examples of the aliphatic dihydroxy compound for deriving the dihydroxy structural unit in the general formula (2) include ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-pentanediol, pentamethylenediol, 2,4- Pentanediol, 1,5-hexanediol, hexamethylene glycol, 1,5-heptanediol, heptamethylenediol, octamethylenediol, 1,9-nonanediol, 1,10-decamethyleneglycol, 1,6-cyclohexanediol Of these, ethylene glycol, propylene glycol, and 1,4-butanediol are preferable.

  The dihydroxy compound that derives the dihydroxy structural unit in the general formula (1) and the general formula (2) is used by adjusting the amount used so that n / m + n> 0.5 in the polyarylate resin.

  In this polymerization, phenol, o, m, p-cresol, o, m, p-ethylphenol, o, m, p-propylphenol, o, m, p-tert-butylphenol, pentyl are used as molecular weight regulators. Alkylphenols such as phenol, hexylphenol, octylphenol and nonylphenol, monofunctional phenols such as o, m, p-phenylphenol, acetic acid chloride, butyric acid chloride, octylic acid chloride, benzoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride , Monofunctional acid halides such as sulfinyl chloride, benzenephosphonyl chloride and substituted products thereof may be present.

  After the polymerization, the resin is purified by washing the resin solution with an aqueous alkali solution such as sodium hydroxide or potassium hydroxide, an acid aqueous solution such as hydrochloric acid, nitric acid or phosphoric acid, water, and the like, followed by stationary separation, centrifugation, etc. It may be separated. Also, purify the produced resin solution by a method in which the resin solution is precipitated in a solvent insoluble in the resin, a method in which the resin solution is dispersed in warm water and the solvent is distilled off, or a method in which the resin solution is circulated through an adsorption column. Also good.

  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 in a dispersion medium in which the resin is insoluble, or the solvent is removed by heating, decompression, etc. It may be taken out by distilling off, or when taken out in the form of a slurry, the solid can be taken out by a centrifugal separator or a filter.

  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 at a temperature not lower than 20 ° C. and not higher than the melting temperature of the resin. The drying time is at least the time until the purity of impurities such as the residual solvent becomes below a certain level, but it is usually dried for at least the time at which the residual solvent becomes 1000 ppm or less, preferably 300 ppm or less, more preferably 100 ppm or less.

  The polyarylate resin used in the present invention has a viscosity average molecular weight of 10,000 or more and 300,000 or less, preferably 15,000 or more and 100,000 or less, more preferably 20,000 or more and 50,000 or less. If the viscosity average molecular weight is less than 10,000, the mechanical strength of the resin is lowered and is not practical, and if it is 300,000 or more, it is difficult to apply to an appropriate film thickness.

  The polyarylate resin used in the present invention can be mixed with other resins and used for an electrophotographic photoreceptor. Other resins mixed here include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resins, Various thermosetting resins are exemplified. Among these resins, a polycarbonate resin is preferable.

  In the present invention, when the polyarylate resin is used as a binder resin by mixing with other resins, the content of the polyarylate resin of the present invention is 30% by weight or more, preferably 50% by weight or more in the total binder resin. Is 70% by weight or more. When the polyarylate resin of the present invention is 30% by weight or less, sufficient surface slipperiness, abrasion resistance and good electrical properties are not exhibited, which is not preferable.

  The polyarylate resin of the present invention may be a copolymer of the structure of the general formulas (1) and (2) and other resins. The copolymer form may be a block, graft or multi-block copolymer. Examples of other resin structures copolymerized here include various resins such as polycarbonate, polyarylate, polysulfone, polyether, polyketone, polyamide, polysiloxane, polyimide, polystyrene, and polyolefin. Particularly preferred is polycarbonate resin.

  Hereinafter, the present invention will be described in more detail with reference to production examples, examples and comparative examples. In addition, this invention is not limited to the manufacturing method by the manufacturing example shown here.

[Manufacture of polyarylate resin]
Production Example 1 (Production Method of Polyarylate Resin A of Example 1)
Sodium hydroxide (8.06 g) and water (282 ml) were weighed in a 1 L beaker, and stirred and dissolved while bubbling nitrogen. In this order, p-tert-butylphenol (0.3372 g), benzyltriethylammonium chloride (0.0989 g) and bis (4-hydroxy-3,5-dimethylphenyl) methane [tetramethylbisphenol F] (19.84 g) were sequentially added. After addition and stirring, the aqueous alkaline solution was transferred to a 2 L reaction vessel.

  Separately, isophthalic acid chloride (4.82 g) and terephthalic acid chloride (11.24 g) were dissolved in dichloromethane (141 ml) and transferred into a dropping funnel. While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the alkaline aqueous solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 3 hours, acetic acid (2.7 ml) and dichloromethane (140 ml) were added and stirred for 30 minutes. Then, stirring was stopped and the organic layer was separated. This organic layer was washed twice with 0.1N aqueous sodium hydroxide (210 ml), then washed twice with 0.1N hydrochloric acid (210 ml), and further washed twice with water (210 ml). went.

  The washed organic layer was poured into methanol (2000 ml), and the resulting precipitate was removed by filtration and dried to obtain the desired polyarylate resin A. The resulting polyarylate resin A had a viscosity average molecular weight of 26,900. The structural formula is shown below.

Production Example 2 (Production Method of Polyarylate Resin B of Example 2)
Sodium hydroxide (7.26 g) and water (600 ml) were weighed in a 1 L beaker and stirred and dissolved while bubbling nitrogen. Thereto, p-tert-butylphenol (0.3035 g), benzyltriethylammonium chloride (0.0890 g) and bis (4-hydroxy-3,5-dimethylphenyl) methane [tetramethylbisphenol F] (17.86 g) in this order. After addition and stirring, the aqueous alkaline solution was transferred to a 2 L reaction vessel.

  Separately, isophthalic acid chloride (7.22 g) and terephthalic acid chloride (7.22 g) were dissolved in dichloromethane (300 ml) and transferred into a dropping funnel. While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the alkaline aqueous solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 3 hours, acetic acid (2.4 ml), dichloromethane (100 ml) and water (100 ml) were added and stirred for 30 minutes. Then, stirring was stopped and the organic layer was separated. This organic layer was washed twice with 0.1N aqueous sodium hydroxide (600 ml), then washed twice with 0.1N hydrochloric acid (600 ml), and further washed twice with water (600 ml). went.

  The washed organic layer was poured into methanol (2000 ml), and the resulting precipitate was removed by filtration and dried to obtain the desired polyarylate resin B. The resulting polyarylate resin B had a viscosity average molecular weight of 37,900. The structural formula is shown below.

Production Example 3 (Production Method of Polyarylate Resin C of Reference Example 1 )
Sodium hydroxide (4.96 g) and water (400 ml) were weighed in a 1 L beaker and stirred and dissolved while bubbling nitrogen. There, p-tert-butylphenol (0.2053 g), benzyltriethylammonium chloride (0.0602 g) and 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] (2.30 g), bis (4-hydroxy After adding and stirring in the order of −3,5-dimethylphenyl) methane [tetramethylbisphenol F] (9.67 g), the aqueous alkaline solution was transferred to a 1 L reaction vessel.

  Separately, isophthalic acid chloride (4.89 g) and terephthalic acid chloride (4.89 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. and stirring the alkaline aqueous solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 3 hours, acetic acid (1.61 ml), dichloromethane (100 ml) and water (50 ml) were added and stirred for 30 minutes. Then, stirring was stopped and the organic layer was separated. This organic layer was washed twice with 0.1N sodium hydroxide aqueous solution (450 ml), then washed twice with 0.1N hydrochloric acid (450 ml), and further washed twice with water (450 ml). went.

  200 ml of methylene chloride was added to the organic layer after washing, and the precipitate obtained by pouring into methanol (2000 ml) was taken out by filtration and dried to obtain the desired polyarylate resin C. The resulting polyarylate resin C had a viscosity average molecular weight of 38,100. The structural formula is shown below.

Production Example 4 (Method for producing polyarylate resin D of Example 4)
Sodium hydroxide (7.55 g) and water (600 ml) were weighed in a 1 L beaker and stirred and dissolved while bubbling nitrogen. In this order, p-tert-butylphenol (0.1089 g), benzyltriethylammonium chloride (0.0926 g), and bis (4-hydroxy-3,5-dimethylphenyl) methane [tetramethylbisphenol F] (18.58 g) were added in this order. After addition and stirring, the aqueous alkaline solution was transferred to a 2 L reaction vessel.

  Separately, fumaric acid chloride (3.40 g) and terephthalic acid chloride (10.52 g) were dissolved in dichloromethane (300 ml) and transferred into a dropping funnel. While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the alkaline aqueous solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 3 hours, acetic acid (2.5 ml), dichloromethane (150 ml) and water (75 ml) were added and stirred for 30 minutes. Then, stirring was stopped and the organic layer was separated. This organic layer was washed twice with 0.1N aqueous sodium hydroxide solution (675 ml), then washed twice with 0.1N hydrochloric acid (675 ml), and further washed twice with water (675 ml). went.

  The washed organic layer was poured into methanol (2000 ml), and the resulting precipitate was removed by filtration and dried to obtain the desired polyarylate resin D. The resulting polyarylate resin D had a viscosity average molecular weight of 26,800. Structural formula C is shown below.

Production Example 5 (Production Method of Polyarylate Resin E of Comparative Example 1)
In Production Example 3, 6.18 g of 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] and 5.50 g of bis (4-hydroxy-3,5-dimethylphenyl) methane [tetramethylbisphenol F] Except having changed, it carried out similarly to manufacture example 3, and obtained the target polyarylate resin E. The resulting polyarylate resin E had a viscosity average molecular weight of 57,700. The structural formula is shown below.

Production Example 6 (Production Method of Polyarylate Resin F of Comparative Example 2)
Sodium hydroxide (6.77 g) and water (600 ml) were weighed in a 1 L beaker and stirred and dissolved while bubbling nitrogen. There, p-tert-butylphenol (0.2830 g), benzyltriethylammonium chloride (0.0830 g) and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane [tetramethylbisphenol A] (18. After adding and stirring in the order of 48 g), the aqueous alkaline solution was transferred to a 2 L reaction vessel.

  Separately, isophthalic acid chloride (4.04 g) and terephthalic acid chloride (9.43 g) were dissolved in dichloromethane (300 ml) and transferred into a dropping funnel. While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the alkaline aqueous solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 3 hours, acetic acid (2.23 ml), dichloromethane (150 ml) and water (75 ml) were added and stirred for 30 minutes.

  Then, stirring was stopped and the organic layer was separated. This organic layer was washed twice with 0.1N sodium hydroxide aqueous solution (810 ml), then washed twice with 0.1N hydrochloric acid (810 ml), and further washed twice with water (810 ml). went. The washed organic layer was poured into methanol (1500 ml), and the resulting precipitate was removed by filtration and dried to obtain the desired polyarylate resin F. The resulting polyarylate resin F had a viscosity average molecular weight of 12,400. The structural formula is shown below.

Production Example 7 (Production Method of Polyarylate Resin G of Comparative Example 3)
Sodium hydroxide (8.48 g) and water (600 ml) were weighed in a 1 L beaker and stirred and dissolved while bubbling nitrogen. Thereto was added p-tert-butylphenol (0.3548 g), benzyltriethylammonium chloride (0.1040 g) and bis (4-hydroxyphenyl) methane [bisphenol F] (16.31 g) in this order, followed by stirring. The aqueous solution was transferred to a 2L reactor.

  Separately, isophthalic acid chloride (5.10 g) and terephthalic acid chloride (11.81 g) were dissolved in dichloromethane (300 ml) and transferred into a dropping funnel. While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the alkaline aqueous solution in the reaction tank, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 3 hours, acetic acid (2.8 ml), dichloromethane (150 ml) and water (75 ml) were added and stirred for 30 minutes. Then, stirring was stopped and the organic layer was separated.

  This organic layer was washed twice with 0.1N sodium hydroxide aqueous solution (810 ml), then washed twice with 0.1N hydrochloric acid (810 ml), and further washed twice with water (810 ml). went. The washed organic layer was poured into methanol (1500 ml), and the resulting precipitate was removed by filtration and dried to obtain the desired polyarylate resin G. The resulting polyarylate resin G was insoluble in organic solvents. The estimated structure of the obtained resin is shown below.

[Viscosity average molecular weight]
Polyarylate resin was dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. The flow time t of the sample solution was measured in a constant temperature water bath set at 20.0 ° C. using an Ubbelohde capillary viscometer with a flow time t0 of the solvent (dichloromethane) of 136.16 seconds. The viscosity average molecular weight Mv was calculated according to the following formula.

[Example 1]
Manufacture of Photoconductor (Manufacture of Charge Generation Layer) 10 parts by weight of β-type oxytitanium phthalocyanine was added to 150 parts by weight of 4-methoxy-4-methylpentanone-2, and pulverized and dispersed in a sand grind mill.

  Further, 5% of 5% 1,2-dimethoxyethane solution of polyvinyl butyral (trade name Denkabutyral # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) and 5% of phenoxy resin (trade name PKHH, manufactured by Union Carbide) 1, A binder solution was prepared by mixing 100 parts of a 2-dimethoxyethane solution. 100 parts by weight of the binder solution and an appropriate amount of 1,2-dimethoxyethane were added to 160 parts by weight of the previously prepared pigment dispersion to finally prepare a dispersion having a solid content concentration of 4.0%.

The dispersion thus obtained was applied onto a polyethylene terephthalate film having aluminum deposited on the surface so as to have a film thickness of 0.4 μm to provide a charge generation layer.
(Production of charge transport layer) Next, on this film, 60 parts of charge transport material [1] shown below, 100 parts of polyarylate resin A having a viscosity average molecular weight of 26,900 produced in Production Example 1, and a leveling agent A solution prepared by dissolving 0.03 part of silicone oil in a mixed solvent of toluene and tetrahydrofuran 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 polyarylate resin was good. The following evaluation was performed on the photoreceptor thus obtained.

[Friction test]
The surface of the photosensitive member prepared above is uniformly loaded with 0.1 mg / cm ² and contacted with urethane rubber made of the same material as the cleaning blade, and used at an angle of 45 degrees. The dynamic friction coefficient at the 100th time when the urethane rubber was moved 100 times with a load of 200 g, 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. The results are shown in Table 1.

[Abrasion test]
The photoreceptor film was cut into a circle having a diameter of 10 cm, and the wear was evaluated by a Taber abrasion tester (manufactured by Toyo Seiki Co., Ltd.). Test conditions were measured by comparing the weight before and after the test with 1000 wheels without load (the weight of the wear wheel) under the atmosphere of 23 ° C. and 50% RH and without wear (self-weight of the wear wheel). did. The results are shown in Table 1.

[Electrical characteristics]
Using an electrophotographic characteristic evaluation apparatus (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, pages 404-405) prepared according to the Electrophotographic Society measurement standard, the photoconductor is made into an aluminum drum. Attached to a cylindrical shape, the aluminum drum and the aluminum substrate of the photoconductor are connected, and then the drum is rotated at a fixed number of revolutions, and an electrical property evaluation test is performed by a cycle of charging, exposure, potential measurement, and static elimination. went. At that time, the initial surface potential was set to −700 V, the exposure was performed at 780 nm, the charge removal was performed at 660 nm, and the surface potential (VL) when 780 nm light was irradiated at 2.4 μJ / cm ² was measured. In the VL measurement, the time required for the exposure-potential measurement was set to 139 ms. The measurement environment was 5 ° C. and 10% relative humidity (L / L) and 25 ° C. and 50% relative humidity (N / N). The results are shown in Table 1. The smaller the absolute value of the surface potential (VL), the better the response.

[Example 2]
A photoconductor was manufactured in the same manner as in Example 1 except that the polyarylate resin A in Example 1 was the same as that in Example 2 except that the polyarylate resin B having a viscosity average molecular weight of 37,900 was used. At this time, the solubility of the polyarylate resin B was good. The obtained photoreceptor was subjected to a friction test, a wear test, and an evaluation of electrical characteristics under the same conditions as in Example 1. The results are shown in Table 1.

[ Reference Example 1 ]
A photoconductor was manufactured in the same manner as in Example 1 except that the polyarylate resin A in Example 1 was the same as that in Example 3 except that the polyarylate resin C having a viscosity average molecular weight of 38,100 was used. At this time, the solubility of the polyarylate resin C was good. The obtained photoreceptor was subjected to a friction test, a wear test, and an evaluation of electrical characteristics under the same conditions as in Example 1. The results are shown in Table 1.

[Example 4]
A photoconductor was manufactured in the same manner as in Example 1 except that the polyarylate resin A in Example 1 was the same as that in Example 4 except that the polyarylate resin D having a viscosity average molecular weight of 26,800 was used. At this time, the solubility of the polyarylate resin D was good. The obtained photoreceptor was subjected to a friction test, a wear test, and an evaluation of electrical characteristics under the same conditions as in Example 1. The results are shown in Table 1.

[Example 5]
A photoconductor was produced in the same manner as in Example 1 except that 60 parts of the charge transport material [1] were changed to 40 parts of the following charge transport material [2] in the production of the photoconductor of Example 1. The obtained photoreceptor was subjected to a friction test, a wear test, and an evaluation of electrical characteristics under the same conditions as in Example 1. The results are shown in Table 2.

[Comparative Example 1]
The same operation as in Example 1 was performed, except that the polyarylate resin A in Example 1 was the polyarylate resin E having a viscosity average molecular weight of 57,700 produced in Production Example 5. At this time, the solubility of the polyarylate resin E was good. The obtained photoreceptor was subjected to a friction test, a wear test, and an evaluation of electrical characteristics under the same conditions as in Example 1. The results are shown in Table 1.

[Comparative Example 2]
The same operation as in Example 1 was performed except that the polyarylate resin A in Example 1 used the polyarylate resin F having a viscosity average molecular weight of 12,400 produced in Production Example 6. At this time, the solubility of the polyarylate resin F was good. The obtained photoreceptor was subjected to a friction test, a wear test, and an evaluation of electrical characteristics under the same conditions as in Example 1. The results are shown in Table 1.

[Comparative Example 3]
An attempt was made to prepare a photoconductor in the same manner as in Example 1 except that the polyarylate resin A in Example 1 was the same as in Example 1 except that the polyarylate resin G produced in Production Example 7 was used. Since it was insoluble, a photoreceptor could not be obtained.

[Comparative Example 4]
In Example 5, 100 parts of the polyarylate resin A in Example 5 was changed to a mixture of 25 parts of the polyarylate resin A in Example 5 and 75 parts of the polycarbonate resin A shown below, and the toluene / tetrahydrofuran mixed solvent was changed to a dioxane / tetrahydrofuran mixed solvent. A photoreceptor was prepared in the same manner as in Example 5 except that. The obtained photoreceptor was subjected to a friction test, a wear test, and an electrical property evaluation under the same conditions as in Example 5. The results are shown in Table 2.

[Comparative Example 5]
A photoconductor was prepared in the same manner as in Comparative Example 4 except that the polyarylate resin A in Example 5 was changed to the polycarbonate resin A in Comparative Example 4 in the production of the photoconductor of Example 5. The obtained photoreceptor was subjected to a friction test, a wear test, and an evaluation of electrical characteristics under the same conditions as in Example 1. The results are shown in Table 2.

  From the above results, it can be seen that by using a specific polyarylate resin, an electrophotographic photoreceptor excellent in mechanical properties such as wear resistance and slipping property can be obtained while maintaining good electrical characteristics.

Claims (9)

In an electrophotographic photosensitive member having at least a photosensitive layer on a conductive substrate, the binder resin of the photosensitive layer has structural units represented by the following general formulas (1) and (2), and is an interfacial polymerization method. An electrophotographic photosensitive member comprising: a polyarylate resin obtained by the above formula, wherein n / (n + m)> 0.9 , and the polyarylate resin exceeds 30% by weight in the total binder resin.

(In General Formula (1), R < ¹ > -R < ⁸ > shows a hydrogen atom and the alkyl group which may be substituted each independently, Z shows a bivalent coupling group.
However, at least one of R ^{1 to} R ^{8 is} an optionally substituted alkyl group. In general formula (2), Y and Z represent a divalent linking group, and general formula (2) represents a structure different from general formula (1). ) In the general formula (1), R ² , R ⁴ , R ⁵ and R ⁷ are hydrogen atoms, and R ¹ , R ³ , R ⁶ and R ⁸ are alkyl groups which may be substituted. The electrophotographic photosensitive member described. The electrophotographic photosensitive member according to claim ² , wherein, in the general formula (1), R ² , R ⁴ , R ⁵ and R ⁷ are hydrogen atoms, and R ¹ , R ³ , R ⁶ and R ⁸ are methyl groups. .   The electrophotographic photosensitive member according to claim 1, wherein Z in the general formulas (1) and (2) is a phenylene group.   The electrophotographic photosensitive member according to claim 1, wherein the polyarylate resin contains two or more kinds of dicarboxylic acid structural units. The electrophotographic photosensitive member according to claims 1 to 5 viscosity average molecular weight of polyarylate resin is characterized in that 15,000 to 100,000. The photosensitive layer, as a charge transfer agent, hydrazone derivatives, aromatic amine derivatives, according to claims 1 to 6, characterized in that it contains at least one of stilbene derivative, a butadiene derivative, or a compound wherein the derivative is more bound, Electrophotographic photoreceptor. The electrophotographic photoreceptor according to claim 7 , wherein the photosensitive layer contains an aromatic amine compound represented by the following general formula (3) as a charge transfer agent.

(In General Formula (3), Ar ^{1 to} Ar ⁴ each independently represent an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent. Ar ⁵ and Ar ⁶ may each have an alkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent when m1 = 0 and m2 = 0. Represents a good monovalent heterocyclic group. When m1 = 1 and m2 = 1, each has an alkylene group which may have a substituent, an arylene group which may have a substituent, or a substituent. Represents a divalent heterocyclic group which may optionally be substituted, Q represents a direct bond or a divalent residue, and R ^{9 to} R ¹⁶ each independently represents a hydrogen atom or an optionally substituted alkyl. Group, aryl group optionally having substituent, aralkyl group optionally having substituent, heterocyclic ring optionally having substituent Each independently is .n1~n4 representing a represents an integer of 0 to 4. Also, m1, m @ 2 each independently represents 0 or 1. Also a ring structure by bonding with Ar ¹ to Ar ⁶ each other It may be formed.) Photosensitive layer, an electrophotographic photosensitive member according to claim 1 to 8 charge transport layer and charge generating layer is laminated.