JP4835683B2 - Electrophotographic photoreceptor - Google Patents

Description

  The present invention relates to an electrophotographic photoreceptor. Specifically, an electrophotographic photosensitive member containing a resin for an electrophotographic photosensitive member that is excellent in abrasion resistance, surface slipperiness, solubility when adjusting a coating solution, and storage stability of a coating solution, and has excellent electrical response. It is about.

Electrophotographic technology is widely used in fields such as copiers and various printers because of its immediacy and high quality images.
As a photoreceptor which is the core of electrophotographic technology, a photoreceptor using an organic photoconductive material having advantages such as non-pollution, easy film formation, and easy manufacture is used.
As a photoreceptor using an organic photoconductive material, a so-called dispersion type photoreceptor in which a photoconductive fine powder is dispersed in a binder resin, and a laminate type photoreceptor in which a charge generation layer and a charge transport layer are laminated are known. ing. Multilayered photoreceptors can be obtained by combining highly efficient charge generating substances and charge transporting substances, so that highly sensitive photoreceptors can be obtained, and a wide range of materials can be selected and highly safe photoreceptors can be obtained. The layer can be easily formed by coating, has high productivity, and is advantageous in terms of cost. Therefore, it is the mainstream of photoreceptors, and has been developed and put into practical use.

  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 normally used as a charger, which gives chemical damage to the photosensitive layer, and carriers (current) generated by image exposure. There are chemical and electrical degradations caused by flowing in the photosensitive layer, static elimination light, and decomposition of the photosensitive layer composition by external light. Further, there is mechanical deterioration such as abrasion of the surface of the photosensitive layer due to rubbing of a cleaning blade, a magnetic brush or the like, contact with a developer, paper, and the like, and film peeling. In particular, such damage on the surface of the photosensitive layer tends to appear on the image and directly impairs the image quality, which is a major factor limiting 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 the case of a general photoreceptor having no functional layer such as a surface protective layer, it is the photosensitive layer that receives such a load. The photosensitive layer is usually composed of a binder resin and a photoconductive substance, and it is the binder resin that substantially determines the strength. However, since the amount of the photoconductive substance doped is considerably large, sufficient mechanical strength is provided. Has not reached.
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 transport layer, especially the charge transport material, but varies greatly depending on the binder resin.

  In addition, each layer constituting these electrophotographic photoreceptors usually has a coating liquid containing a photoconductive substance, a binder resin, etc. on a support, dip coating, spray coating, nozzle coating, bar coating, roll coating, It is formed by coating by blade coating or the like. In these layer forming methods, a known method such as coating is applied as a coating solution obtained by dissolving a substance contained in a layer in a solvent. In many processes, a coating solution is prepared in advance and stored. Therefore, the binder resin is required to have excellent solubility in the solvent used in the coating process and the stability of the coating solution after dissolution.

  Examples of the binder resin for the photosensitive layer 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 resin, and various kinds of heat. A curable resin is used. Among the various binder resins, the polycarbonate resin has relatively excellent performance, and various polycarbonate resins have been developed and put to practical use (for example, see Patent Documents 1 to 4).

On the other hand, the technology of an electrophotographic photoreceptor using a polyarylate resin marketed under the trade name “U-polymer” as a binder is disclosed, and it shows that sensitivity is particularly superior to polycarbonate. (For example, refer to Patent Document 5).
In addition, a technique for an electrophotographic photoreceptor using a polyarylate resin using a dihydric phenol component having a specific structure as a binder resin is disclosed, and the solution stability at the time of producing the photoreceptor is improved, especially the mechanical strength. It is known that the wear resistance is excellent (see, for example, Patent Documents 6 and 7).

However, conventional photoconductors have disadvantages such as surface wear due to practical loads such as development with toner, friction with paper, friction with a cleaning member (blade), and scratches on the surface. Therefore, the current situation is that the printing performance is limited in practical use.
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. 10-288845

The electrophotographic photosensitive member using the conventionally known binder resin is improved in strength and the like, but is insufficient in terms of electrical characteristics, or has poor stability when used as a coating solution for forming a photosensitive layer. Or gelled.
The object of the present invention is that the coating solution for forming a photosensitive layer has high stability, excellent electrical characteristics, and high mechanical strength, such as development with toner, friction with paper, and friction with a cleaning member (blade). An object of the present invention is to provide an electrophotographic photoreceptor in which the surface is not easily worn and damaged even under the load of.

By including a specific polyester resin in the photosensitive layer, the present inventors have sufficient mechanical properties, high solubility in the solvent used for the photosensitive layer forming coating solution, and excellent coating solution stability. It has been found that a photoconductor having an excellent electrical property can be obtained, and the present invention has been achieved.
That is, the gist of the present invention is that, in an electrophotographic photosensitive member having a photosensitive layer made of a photoconductive substance and a binder resin on a conductive substrate, the photosensitive layer is composed only of a repeating structure represented by the following general formula (1). The electrophotographic photoreceptor includes a polyester resin.

(In the formula (1), R ^{1 to} R ⁸ each independently represents a hydrogen atom or a methyl group. R ⁹ is a hydrogen atom or a methyl group, and R ¹⁰ has 4 to 10 carbon atoms having a branched structure. It represents the following chain alkyl group.)

  According to the present invention, the photosensitive layer contains the polyester resin specific to the present invention, so that the coating solution for forming the photosensitive layer has high stability, excellent electrical characteristics, high mechanical strength, and development with toner. It is possible to provide an electrophotographic photosensitive member that is less likely to be worn and scratched by practical loads such as friction with paper and friction with a cleaning member (blade).

The photosensitive layer of the electrophotographic photosensitive member of the present invention contains the polyester resin specific to the present invention, and the resin is used as a binder resin for the photosensitive layer provided on the conductive support of the photosensitive member.
As a specific configuration of the photosensitive layer of the present invention, a laminate 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 on a conductive support. Examples such as a dispersion type (single layer type) photoreceptor having a photosensitive layer in which a charge generating substance is dispersed in a layer containing a charge transporting substance and a binder resin on a conductive photoreceptor, a conductive support, etc. In the present invention, the polyester resin is usually used for a layer containing a charge transport material, and preferably used for a charge transport layer of a laminated photosensitive layer.
<Polyester resin>
The photosensitive layer of the electrophotographic photosensitive member of the present invention is a polyester resin composed only of a repeating structure in which the photosensitive layer is represented by the following general formula (1) and a dihydric phenol residue and an aromatic dicarboxylic acid residue are bonded. contains.

In formula (1), R ^{1 to} R ⁸ each independently represents a hydrogen atom or an alkyl group. R ⁹ represents a hydrogen atom or a methyl group, and R ¹⁰ represents a chain alkyl group having a branched structure and having 4 to 30 carbon atoms.
The polyester resin of the present invention can be produced from a dihydric phenol component and an aromatic dicarboxylic acid component by a known method.

Considering the ease of production of the dihydric phenol component used in producing the polyester resin, R ^{1 to} R ⁸ are preferably a hydrogen atom or an alkyl group having 15 or less carbon atoms, more preferably a hydrogen atom or 6 carbon atoms. Hereinafter, it is an alkyl group, more preferably a hydrogen atom or a methyl group. Among these, a hydrogen atom is particularly preferable.
R ⁹ represents a hydrogen atom or a methyl group, and R ¹⁰ represents a chain alkyl group having a branched structure and having 4 to 30 carbon atoms. The chain alkyl group having 4 to 30 carbon atoms and having a branched structure represented by R ¹⁰ may have at least one branched chain, and may have a plurality of branched chains. In consideration of the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution when the photosensitive layer is applied and formed, R ¹⁰ is preferably a branched alkyl group having 20 or less carbon atoms, more preferably a carbon number. A branched alkyl group having 10 or less, particularly preferably a branched alkyl group having 8 or less carbon atoms. Although there is no restriction | limiting in particular in carbon number of a branched chain, when the ease in manufacture is considered, carbon number 10 or less is preferable and especially 5 or less is preferable. The branched chain may be bonded to any position of the main chain, for example, isopropyl group, isobutyl group, sec-butyl group, tert-pentyl group, 1-methylbutyl group, 1-methylheptyl group, 1-ethyl A branched chain may be bonded to the first carbon atom bonded to the dihydric phenol residue, such as a pentyl group.

  Specific examples of the dihydric phenol component that gives the dihydric phenol residue constituting the repeating structure represented by the formula (1) include 1,1-bis (4-hydroxyphenyl) -3-methylbutane, 1,1 -Bis (3-methyl-4-hydroxyphenyl) -3-methylbutane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) -3-methylbutane, 1,1-bis (3-ethyl-4) -Hydroxyphenyl) -3-methylbutane, 1,1-bis (3,5-diethyl-4-hydroxyphenyl) -3-methylbutane, 1,1-bis (3-propyl-4-hydroxyphenyl) -3-methylbutane 1,1-bis (3,5-dipropyl-4-hydroxyphenyl) -3-methylbutane, 1,1-bis (3- (t-butyl) -4-hydroxyphenyl) -3 Methylbutane, 1,1-bis (3,5-di (t-butyl) -4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2,2- Bis (3-methyl-4-hydroxyphenyl) -4-methylpentane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) -4-methylpentane, 2,2-bis (3-ethyl- 4-hydroxyphenyl) -4-methylpentane, 2,2-bis (3,5-diethyl-4-hydroxyphenyl) -4-methylpentane, 2,2-bis (3-propyl-4-hydroxyphenyl)- 4-methylpentane, 2,2-bis (3,5-dipropyl-4-hydroxyphenyl) -4-methylpentane, 2,2-bis (3- (t-butyl) -4-hydroxyphene L) -4-methylpentane, 2,2-bis (3,5-di (t-butyl) -4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-hydroxyphenyl) -2- Ethyl hexane, 1,1-bis (3-methyl-4-hydroxyphenyl) -2-ethylhexane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) -2-ethylhexane, 1,1 -Bis (3-ethyl-4-hydroxyphenyl) -2-ethylhexane, 1,1-bis (3,5-diethyl-4-hydroxyphenyl) -2-ethylhexane, 1,1-bis (3-propyl) -4-hydroxyphenyl) -2-ethylhexane, 1,1-bis (3,5-dipropyl-4-hydroxyphenyl) -2-ethylhexane, 1,1-bis (3- (t-butyl) -4 - Droxyphenyl) -2-ethylhexane, 1,1-bis (3,5-di (t-butyl) -4-hydroxyphenyl) -2-ethylhexane, 2,2-bis (4-hydroxyphenyl)- 3-ethylheptane, 2,2-bis (3-methyl-4-hydroxyphenyl) -3-ethylheptane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) -3-ethylheptane, 2 , 2-bis (3-ethyl-4-hydroxyphenyl) -3-ethylheptane, 2,2-bis (3,5-diethyl-4-hydroxyphenyl) -3-ethylheptane, 2,2-bis (3 -Propyl-4-hydroxyphenyl) -3-ethylheptane, 2,2-bis (3,5-dipropyl-4-hydroxyphenyl) -3-ethylheptane, 2,2-bis (3- (t-butyl) ) -4-hydroxyphenyl) -3-ethylheptane, 2,2-bis (3,5-di (t-butyl) -4-hydroxyphenyl) -3-ethylheptane, and the like. 1-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 2, 2-bis (4-hydroxyphenyl) -3-ethylheptane, particularly preferably 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-hydroxyphenyl)- 2-ethylhexane.

  The part represented by Formula (3) in Formula (1) is an aromatic dicarboxylic acid residue which the repeating structure of the polyester resin used by this invention has, Preferably it is a terephthaloyl group or an isophthaloyl group. The polyester resin may be a copolymer having a repeating structure having a terephthaloyl group and a repeating structure having an isophthaloyl group. As the aromatic dicarboxylic acid raw material corresponding to the terephthaloyl group and the isophthaloyl group, a terephthalic acid derivative and an isophthalic acid derivative are used, and more specifically, for example, terephthalic acid chloride and isophthalic acid chloride are used. A mixture of these may also be used.

  The molar ratio of the repeating structure having a terephthaloyl group and the repeating structure having an isophthaloyl group in the polyester resin used in the present invention is the sum of the repeating structure having a terephthaloyl group and the repeating structure having an isophthaloyl group. The ratio of the structure having is usually 1% by weight or more and 100% by weight or less. If the ratio of the structure having a terephthaloyl group is small, the electrical properties when the photosensitive member is obtained is deteriorated and the mechanical properties are unfavorably deteriorated. Therefore, it is preferably 50% by weight or more, more preferably 90% by weight. As described above, particularly preferred is a repeating structure in which the entire amount is composed of terephthaloyl groups.

  Further, the polyester resin of the present invention can be mixed with other resins and used for an electrophotographic photoreceptor. Other resins used here include vinyl polymers such as polymethyl methacrylate, polystyrene, polyvinyl chloride, and copolymers thereof, polycarbonate, polyester, polyester polycarbonate, polysulfone, phenoxy, epoxy, silicone resin, etc. Examples thereof include a plastic resin and various thermosetting resins. Of these resins, polycarbonate resin is preferable.

The mixing ratio of the resin to be used in combination is not particularly limited, but in order to obtain the effects of the present invention sufficiently, it is preferable to use it in a range not exceeding the ratio of the polyester resin of the present invention, especially other It is preferable not to use these resins together.
<Method for producing polyester resin>
As a method for producing the polyester resin of the present invention, a known polymerization method can be used, and examples thereof include an interfacial polymerization method, a melt polymerization method, and a solution polymerization method.

Among known polymerization methods, for example, in the case of production by an interfacial polymerization method, a solution in which a dihydric phenol component is dissolved in an alkaline aqueous solution and a halogenated hydrocarbon solution in which an aromatic dicarboxylic acid chloride component is 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 1.01-3 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.

Quaternary ammonium salts or quaternary phosphonium salts used as catalysts include 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.

  In this polymerization, phenol, o, m, p-cresol, o, m, p-ethylphenol, o, m, p-propylphenol, o, m, p- (t-butyl) are used as molecular weight regulators. Phenol, pentylphenol, hexylphenol, octylphenol, nonylphenol, o-cresol, 2,5-dimethylphenol, 2,6-dimethylphenol, 2,3,5-trimethylphenol, 2,4,5-trimethylphenol, 2, 3,4,5-tetramethylphenol, 2,5-dimethyl-4- (t-butyl) phenol, 2,5-dimethyl-4-nonylphenol, 2,5-dimethyl-4-acetylphenol, α-tocopherol, phenol derivatives such as o, m, p-phenylphenol, acetic chloride, butyric chloride, oct Le acid chloride, benzoyl chloride, benzene sulfonyl chloride, benzene sulfinyl chloride, sulfinyl chloride, may be present as benzene phosphonyl chloride or acid halides such as substituted versions thereof. Among these molecular weight regulators, p- (t-butyl) phenol is preferable from the viewpoint of solution stability of the produced polymer.

Further, in the polyester resin having a repeating structure represented by the formula (1), groups existing at the molecular chain terminals such as the molecular weight modifier described above are not included in the repeating unit.
In the polyester resin having a repeating structure represented by the formula (1), the viscosity average molecular weight is usually 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, and usually 300,000 or less. Preferably it is 200,000 or less, More preferably, it is 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.

<Support>
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) 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 for controlling conductivity, surface properties, etc., or for covering defects.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after being subjected to anodizing treatment, chemical conversion coating treatment, or the like. When the anodizing treatment is performed, it is desirable to perform a sealing treatment by a known method.
The support surface 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.

<Underlayer>
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 particles 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 sizes of the metal oxide particles can be used. Among them, from the viewpoint of characteristics and liquid stability, the average primary particle size is usually preferably 100 nm or less, particularly preferably 50 nm or less. . Moreover, the thing of 10 nm or more is preferable.
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, polyvinylpyrrolidone, 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.

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% by weight to 500% by weight from the viewpoint 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. <Charge generation layer>
When the electrophotographic photosensitive member of the present invention is a laminated type photosensitive member, examples of the charge generating material used in the charge generating layer include selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments, and azo pigments. Various photoconductive materials such as organic pigments such as quinacridone pigments, indigo pigments, perylene pigments, 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, titanyl phthalocyanine such as A-type, B-type, and D-type, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, and hydroxygallium phthalocyanine. Of the crystal forms of titanyl phthalocyanine mentioned here, A type and B 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 type A is known as a stable type. The D-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. The phthalocyanine compound may be a single compound or may be in some mixed state. 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 may be used in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, and crystallization. It may be generated. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known.
<Charge transport layer>
Examples of the charge transport material contained in the charge transport layer include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, and electron withdrawing materials such as 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, carbazole derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives and those in which a plurality of these derivatives are bonded are preferable, and those in which a plurality of aromatic amine derivatives, stilbene derivatives, and butadiene derivatives are bonded. preferable.

  Specifically, those having a structure represented by the following general formula (4) are preferably used.

In formula (4), Ar ^{1 to} Ar ⁶ each independently represents an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent. m ¹ and m ² each independently represents 0 or 1; Ar ⁵ when m ¹ = 0 and Ar ⁶ when m ² = 0 each have an alkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a monovalent heterocyclic group, Ar ⁵ when m ¹ = 1, and Ar ⁶ when m ² = 1 each have an alkylene group and a substituent which may have a substituent. An arylene group which may be substituted, or a divalent heterocyclic group which may have a substituent. Q represents a direct bond or a divalent residue. R ^{18 to} R ²⁵ each independently represent a hydrogen atom, an alkyl group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent. n ¹ ~n ⁴ represents an integer of 0 to 4 each independently. Ar ^{1 to} Ar ⁶ may be bonded to each other to form a cyclic structure.

In the general formula (4), R ^{18 to} R ²⁵ each independently have a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. 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, and the like. Are preferred. When the alkyl group has an aryl substituent, examples thereof include a benzyl group and a phenethyl group, and an aralkyl group having 7 to 12 carbon atoms 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.
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.
Particularly preferred among R ^{20 to} R ²⁷ are a methyl group and a phenyl group.

In General Formula (4), Ar ^{1 to} Ar ⁶ each independently represent an arylene group that may have a substituent or a divalent heterocyclic group that may have a substituent. m ¹ and m ² each independently represents 0 or 1; Ar ⁵ when m ¹ = 0 and Ar ⁶ when m ² = 0 each have an alkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a monovalent heterocyclic group, Ar ⁵ when m ¹ = 1, and Ar ⁶ when m ² = 1 each have an alkylene group and a substituent which may have a substituent. Represents an arylene group which may be substituted or a divalent heterocyclic group which may have a substituent, and examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a pyrenyl group, and the like. An aryl group of 6 to 14 is preferable; examples of the arylene group include a phenylene group and a naphthylene group, and a phenylene group is preferable; and a monovalent heterocyclic group is preferably an aromatic heterocyclic ring. Furyl group, thienyl group, pyridyl group, etc. An aromatic heterocyclic ring is more preferable; the divalent heterocyclic group is preferably an aromatic heterocyclic ring, such as a pyridylene group or a thienylene group, and a monocyclic aromatic heterocyclic ring is more preferable.

Of these, Ar ¹ and Ar ² are particularly preferably phenylene groups and Ar ³ is a phenyl group.
Among these groups represented by R ^{18 to} R ²⁵ 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. An alkenyl group; an aralkyl group such as a benzyl group, a naphthylmethyl group, or a phenethyl group; an aryloxy group such as a phenoxy group or a triloxy group; Aryl alkoxy groups such as benzyloxy 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 (4), n ^{1 to} n ⁴ each independently represents an integer of 0 to 4, preferably 0 to 2, and particularly preferably 1. m ¹ and m ² represent 0 or 1, with 0 being preferred.
In general formula (4), Q represents a direct bond or a divalent residue, but a divalent residue is preferably 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—Z—O—], [—Z—O—Z—], [—S -Z-S-], [-Z-Z-] and the like (provided that O represents an oxygen atom, S represents a sulfur atom, Z represents an arylene group or a substituent which may have a substituent). Represents a good alkylene group).

  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 Examples thereof include an alkenyl group having 1 to 6 carbon atoms and an aryl group having 6 to 14 carbon atoms.
Specific charge transport materials that the electrophotographic photoreceptor of the present invention may have include arylamine compounds described in JP-A-9-244278 and aryls described in JP-A-2002-275133. Examples include amine compounds.

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.
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.

The charge transport layer has well-known plasticizers, antioxidants, ultraviolet absorbers, electron withdrawing properties to improve film forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc. You may contain additives, such as a compound, dye, a pigment, and a leveling agent.
Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of dyes and pigments include various pigment compounds and azo compounds.
<Dispersion type (single layer type) photosensitive layer>
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 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 quality.

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.
<Layer formation method>
Each layer constituting these photoreceptors is supported by a dip coating method, a spray coating method, a nozzle coating method, a bar coating method, a roll coating method, a blade coating method, or the like, which is known as a method for forming a photosensitive layer of an electrophotographic photosensitive member. It is formed by coating on top. Among these, the dip coating method is preferable because of its high productivity, but is not limited to the coating method.

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.
<Image forming apparatus>
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, and a developing device 4, and further, a transfer device 5, a cleaning device 6 and a fixing device as necessary. A device 7 is provided.
The electrophotographic photoreceptor 1 is not particularly limited as long as it is the above-described electrophotographic photoreceptor of the present invention, but in FIG. 1, as an example, a drum in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. The photoconductor is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are disposed along the outer peripheral surface of the electrophotographic photosensitive member 1.

The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2, but other corona charging devices such as corotron and scorotron, and contact-type charging devices such as charging brushes are often used.
In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are designed to be removable from the main body of the image forming apparatus as a cartridge including both of them (hereinafter, appropriately referred to as a photosensitive cartridge). For example, when the electrophotographic photoreceptor 1 or the charging device 2 deteriorates, the photoreceptor cartridge can be removed from the image forming apparatus main body, and another new photosensitive cartridge can be mounted on the image forming apparatus main body. ing. Also, the toner described later is often stored in the toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is removed. It can be removed from the main body of the image forming apparatus and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

  The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength slightly shorter than 600 nm to 700 nm, or monochromatic light with a short wavelength of 380 nm to 500 nm. .

  The type of the developing device 4 is not particularly limited, and an arbitrary device such as a dry development method such as cascade development, one-component conductive toner development, two-component magnetic brush development, or a wet development method can be used. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and has a configuration in which toner T is stored inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicon resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.
The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The restricting member 45 is formed of a resin blade such as silicon resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with resin. The regulating member 45 contacts the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

The agitator 42 is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.
The type of the toner T is arbitrary, and in addition to the powdery toner, a polymerized toner using a suspension polymerization method, an emulsion polymerization method, or the like can be used. In particular, when a polymerized toner is used, a toner having a small particle diameter of about 4 to 8 μm is preferable, and the toner particles are used in various shapes ranging from a nearly spherical shape to a shape outside the spherical shape on the potato. be able to. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like that are disposed to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium) P. Is.

There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner.
The fixing device 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. Each of the upper and lower fixing members 71 and 72 includes a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, and a fixing sheet. A member can be used. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.
The type of the fixing device is not particularly limited, and a fixing device of any type such as heat roller fixing, flash fixing, oven fixing, pressure fixing, etc. can be provided including those used here.

In the electrophotographic apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. At this time, charging may be performed by a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.
Subsequently, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1.

The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and the negative polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1.
When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.

After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.
In addition to the above-described configuration, the image forming apparatus may be configured to perform, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

  The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform a pre-exposure process, an auxiliary charging process, or the like, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.

Hereinafter, the present invention will be described in more detail with reference to production examples, examples and comparative examples. In addition, the following Examples are shown in order to demonstrate this invention in detail, This invention is not limited to the manufacture example and Example shown below, unless it is contrary to the meaning. Further, the description of “parts” in the following production examples, examples and comparative examples indicates “parts by weight” unless otherwise specified.
<Manufacture of resin>
[Measurement of viscosity average molecular weight]
The polyester 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 t ₀ of the solvent (dichloromethane) of 136.16 seconds. The viscosity average molecular weight Mv was calculated according to the following formula.

a = 0.438 × η _sp +1 η _sp = t / t ₀ −1
b = 100 × η _sp / C C = 6.00 (g / L)
η = b / a
Mv = 3207 × η ^1.205
Production Example 1 (Resin A)
Sodium hydroxide (5.19 g) and H ₂ O (448 mL) were weighed into a 500 mL beaker and dissolved with stirring. 2,2-bis (4-hydroxyphenyl) -4-methylpentane [hereinafter sometimes referred to as BP-a] (13.35 g) was mixed with the solution, and the aqueous alkaline solution was transferred to a 1 L reaction vessel. did. Benzyltriethylammonium chloride (0.1286 g) and p- (t-butyl) phenol (0.1483 g) were then sequentially added to the reaction vessel.

Separately, a mixed solution of terephthalic acid chloride (10.08 g) and dichloromethane (224 mL) was transferred into the 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 5 hours, dichloromethane (26 mL) was added and stirring was continued for 2 hours. Then, after adding acetic acid (1.88 mL) and stirring for 30 minutes, stirring was stopped and the organic layer was isolate | separated. The organic layer was washed twice with 0.1N aqueous sodium hydroxide solution (188 mL) and then twice with 0.1N hydrochloric acid (188 mL). Further, it was washed twice with H ₂ O (188 mL).

  The organic layer after washing was poured into methanol (1120 mL), and the resulting precipitate was taken out and dried to obtain the desired resin A. The obtained resin A had a viscosity average molecular weight of 108,400. The repeating structure of Resin A is shown below.

Production Example 2 (Resin C)
Sodium hydroxide (4.86 g) and H ₂ O (448 mL) were weighed into a 500 mL beaker and dissolved with stirring. 1,1-bis (4-hydroxyphenyl) -2-ethylhexane [hereinafter sometimes referred to as BP-b] (13.78 g) was added, stirred and dissolved, and then this alkaline aqueous solution was reacted for 1 L. Moved to the tank. Benzyltriethylammonium chloride (0.1203 g) and p- (t-butyl) phenol (0.1387 g) were then sequentially added to the reaction vessel.

Separately, a mixed solution of terephthalic acid chloride (9.43 g) and dichloromethane (224 mL) was transferred into the 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 5 hours, dichloromethane (26 mL) was added and stirring was continued for 2 hours. Then, after adding acetic acid (1.76 mL) and stirring for 30 minutes, stirring was stopped and the organic layer was isolate | separated. The organic layer was washed twice with 0.1N aqueous sodium hydroxide solution (188 mL) and then twice with 0.1N hydrochloric acid (188 mL). Further, it was washed twice with H ₂ O (188 mL).

  The organic layer after washing was poured into methanol (1120 mL), and the resulting precipitate was removed by filtration and dried to obtain the desired resin C. The obtained resin C had a viscosity average molecular weight of 38,500. The repeating structure of Resin C is shown below.

Comparative Production Example 1 (Resin D)
Sodium hydroxide (5.70 g) and H ₂ O (448 mL) were weighed into a 500 mL beaker and dissolved with stirring. 1,1′-bis (4-hydroxyphenyl) -decane [hereinafter sometimes referred to as BP-c] (17.55 g) was mixed with the solution, and the aqueous alkaline solution was transferred to a 1 L reaction vessel. Benzyltriethylammonium chloride (0.1424 g) and p- (t-butyl) phenol (0.2988 g) were then sequentially added to the reaction vessel.

Separately, a mixed solution of terephthalic acid chloride (11.08 g) and dichloromethane (224 mL) was transferred into the 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 5 hours, dichloromethane (26 mL) was added and stirring was continued for 2 hours. Then, after adding acetic acid (2.07 mL) and stirring for 30 minutes, stirring was stopped and the organic layer was separated. The organic layer was washed twice with 0.1N aqueous sodium hydroxide solution (188 mL) and then twice with 0.1N hydrochloric acid (188 mL). Further, it was washed twice with H ₂ O (188 mL).
The organic layer after washing was poured into methanol (1120 mL), and the resulting precipitate was taken out and dried to obtain the desired resin D. The resulting resin D had a viscosity average molecular weight of 30,500. The repeating structure of Resin D is shown below.

Comparative Production Example 2 (Resin E)
Sodium hydroxide (12.69 g) and H ₂ O (423 mL) were weighed into a 500 mL beaker and dissolved with stirring. BP-c (11.82 g) and bis (4-hydroxyphenyl) methane [hereinafter sometimes referred to as p, p′-BPF], (2-hydroxyphenyl) (4-hydroxyphenyl) methane [ Hereinafter, sometimes referred to as o, p′-BPF], a mixture of bis (2-hydroxymethylphenyl) methane [hereinafter sometimes referred to as o, o′-BPF] [mixing ratio p, p′-BPF: o , P′-BPF: o, o′-BPF = about 35:48:17 (hereinafter sometimes referred to as BPF-mix)] (16.92 g), and the aqueous alkaline solution was transferred to a 1 L reactor. did. Benzyltriethylammonium chloride (0.3144 g) and p- (t-butyl) phenol (0.3625 g) were then sequentially added to the reaction vessel.
Separately, a mixed solution of terephthalic acid chloride (24.65 g) and dichloromethane (211 mL) was transferred into the 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 5 hours, dichloromethane (352 mL) was added and stirring was continued for 2 hours. Then, after adding acetic acid (4.60 mL) and stirring for 30 minutes, stirring was stopped and the organic layer was isolate | separated. The organic layer was washed twice with 0.1N aqueous sodium hydroxide solution (424 mL) and then twice with 0.1N hydrochloric acid (424 mL). Further, it was washed twice with H ₂ O (424 mL).
The washed organic layer was poured into methanol (2800 mL), and the resulting precipitate was taken out and dried to obtain the target resin E. The obtained resin E had a viscosity average molecular weight of 39,300. The repeating structure of Resin E is shown below.

Comparative Production Example 3 (Resin F)
Sodium hydroxide (11.49 g) and H ₂ O (423 mL) were weighed into a 500 mL beaker and dissolved with stirring. After mixing BP-c (10.70 g) and bis (4-hydroxy-3,5-dimethylphenyl) methane [hereinafter sometimes referred to as TmBPF] (19.60 g) into the solution, Transferred to 1 L reactor. Benzyltriethylammonium chloride (0.2847 g) and 2,3,6-trimethylphenol (0.2976 g) were then sequentially added to the reaction vessel.
Separately, a mixed solution of terephthalic acid chloride (22.32 g) and dichloromethane (211 mL) was transferred into the 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 5 hours, dichloromethane (352 mL) was added and stirring was continued for 2 hours. Then, after adding acetic acid (4.17 mL) and stirring for 30 minutes, stirring was stopped and the organic layer was isolate | separated. The organic layer was washed twice with 0.1N aqueous sodium hydroxide solution (424 mL) and then twice with 0.1N hydrochloric acid (424 mL). Further, it was washed twice with H ₂ O (424 mL).

  The washed organic layer was poured into methanol (2800 mL), and the resulting precipitate was filtered out and dried to obtain the desired resin F. The obtained resin F had a viscosity average molecular weight of 67,200. The repeating structure of Resin F is shown below.

Comparative Production Example 4 (Resin G)
Using BP-a, TmBPF, and terephthalic acid chloride with the copolymer composition shown in Table 1, the target resin G was obtained by the same production method as in the above Examples. The obtained resin G had a viscosity average molecular weight of 28,000. The repeating structure of the resin G is shown below.

Comparative Production Example 5 (Resin H)
BP-b, TmBPF, and terephthalic acid chloride were charged with the copolymer composition shown in Table 1, and the target resin H was obtained by the same production method as in the above Examples. The obtained resin H had a viscosity average molecular weight of 27,900. The repeating structure of the resin H is shown below.

<Manufacture of photoconductor>
Example 1
10 parts of A-type oxytitanium phthalocyanine showing strong diffraction peaks at Bragg angles (2θ ± 0.2) of 9.3 °, 10.6 ° and 26.3 ° in X-ray diffraction by CuKα ray, and 4-methoxy-4 -150 parts of methylpentanone-2 was mixed and pulverized and dispersed by a sand grind mill to produce a pigment dispersion. As this pigment dispersion and a binder resin solution, 50 parts of a 5 wt% 1,2-dimethoxyethane solution of polyvinyl butyral (trade name Denkabutyral # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) and phenoxy resin (Union Carbide) 50 parts by weight of 1,2-dimethoxyethane solution (product name, PKHH), and a suitable amount of 1,2-dimethoxyethane is added to finally prepare a dispersion having a solid content of 4.0%. did.

The charge generation layer forming coating solution thus obtained is applied onto a polyethylene terephthalate film having aluminum deposited on the surface so that the film thickness after drying is 0.4 μm, and dried to provide a charge generation layer. It was.
On this charge generation layer, 50 parts of the following charge transport material (1) made of a mixture of structural isomers, 100 parts of resin A produced in Production Example 1, 8 parts of an antioxidant (trade name: IRGANOX1076, manufactured by Ciba Geigy), leveling agent As a coating solution for forming a charge transport layer obtained by mixing 0.03 part of silicone oil and 640 parts of a mixed solvent of tetrahydrofuran and toluene (80% by weight of tetrahydrofuran and 20% by weight of toluene), the film thickness after drying is 20 μm. And a charge transport layer was formed by drying at 125 ° C. for 20 minutes to produce a photoreceptor.

At this time, the solubility of Resin A in a mixed solvent of tetrahydrofuran and toluene was good. Moreover, the coating solution for forming the charge transport layer did not show a change such as solidification after being left at room temperature for 1 week.
Example 2
A photoconductor C was produced in the same manner as in Example 1 except that the resin A used in the coating liquid for forming a charge transport layer in Example 1 was changed to the resin C. The coating solution for forming the charge transport layer showed no change such as solidification after standing at room temperature for 1 week.
Comparative Example 1
A photoconductor D was produced in the same manner as in Example 1 except that the resin A used in the coating liquid for forming the charge transport layer in Example 1 was changed to the resin D. The coating solution for forming the charge transport layer showed no change such as solidification after standing at room temperature for 1 week.

Comparative Example 2
A photoconductor E was produced in the same manner as in Example 1 except that the resin A used in the charge transport layer forming coating solution of Example 1 was changed to Resin E. The coating solution for forming the charge transport layer showed no change such as solidification after standing at room temperature for 1 week.
Comparative Example 3
A photoconductor F was produced in the same manner as in Example 1 except that the resin A used in the coating liquid for forming a charge transport layer in Example 1 was changed to the resin F. The coating solution for forming the charge transport layer showed no change such as solidification after standing at room temperature for 1 week.
Comparative Example 4
A photoconductor G was produced in the same manner as in Example 1 except that the resin A used in the charge transport layer forming coating solution of Example 1 was changed to Resin G. The coating solution for forming the charge transport layer showed no change such as solidification after standing at room temperature for 1 week.
Comparative Example 5
A photoconductor H was produced in the same manner as in Example 1 except that the resin A used in the coating liquid for forming the charge transport layer in Example 1 was changed to the resin H. The coating solution for forming the charge transport layer showed no change such as solidification after standing at room temperature for 1 week.
[Electrical characteristics]
Using an electrophotographic characteristic evaluation apparatus manufactured according to the electrophotographic society measurement standard (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, pages 404 to 405), the photoconductor is made into an aluminum drum. Attached to a cylindrical shape, the aluminum drum and the aluminum support 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 is −700 V, monochromatic light of 780 nm is used as exposure light and 660 nm is used as charge removal light, and the surface potential at the time of exposure light irradiation of 2.4 μJ / cm ² (hereinafter sometimes referred to as VL). ) Was measured. In the VL measurement, the time required from the exposure to the potential measurement was 139 ms. The measurement environment was a temperature of 25 ° C., a relative humidity of 50% (hereinafter sometimes referred to as an NN environment), and a temperature of 5 ° C. and a relative humidity of 10% (hereinafter sometimes referred to as an LL environment). The smaller the absolute value of the VL value, the better the response. 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.

  From the above results, the polyester resin of the present invention exhibits high solubility and coating solution stability with respect to the non-halogen solvent used in the coating solution for forming the charge transport layer, and contains the polyester resin. It can be seen that the photoreceptor is excellent in mechanical properties, abrasion resistance and electrical characteristics.

1 is a conceptual diagram illustrating an embodiment of an image forming apparatus using an electrophotographic photosensitive member of the present invention.

Explanation of symbols

1 Photoconductor
2 Charging device (charging roller)
3 Exposure equipment
4 Development device
5 Transfer device
6 Cleaning device
7 Fixing device
41 Developer tank
42 Agitator
43 Supply roller
44 Developing roller
45 Restriction member
71 Upper fixing member (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device
T Toner
P Recording paper

Claims (4)

An electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains a polyester resin having only a repeating structure represented by the following general formula (1).

(In the formula (1), R ^{1 to} R ⁸ each independently represents a hydrogen atom or a methyl group. R ⁹ is a hydrogen atom or a methyl group, and R ¹⁰ has 4 to 10 carbon atoms having a branched structure. It represents the following chain alkyl group.) 2. The repeating structure represented by the formula (1), wherein the aromatic dicarboxylic acid residue represented by the following formula (3) is a terephthalic acid residue and / or an isophthalic acid residue. The electrophotographic photoreceptor described in 1.

  The electrophotographic photosensitive member according to claim 1 or 2, wherein the polyester resin has a viscosity average molecular weight of 15,000 to 200,000. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer contains a compound represented by the following general formula (4).

(In Formula (4), Ar ^{1 to} Ar ⁶ each independently represents an arylene group which may have a substituent or a divalent heterocyclic group which may have a substituent. M ¹ , m ² each independently represents 0 or 1. Ar ⁵ when m ¹ = 0 and Ar ⁶ when m ² = 0 each have an alkyl group which may have a substituent and a substituent. An aryl group that may be substituted, or a monovalent heterocyclic group that may have a substituent, Ar ⁵ when m ¹ = 1 and Ar ⁶ when m ² = 1 each have a substituent. Represents an alkylene group that may be substituted, an arylene group that may have a substituent, or a divalent heterocyclic group that may have a substituent, and Q represents a direct bond or a divalent residue. ¹⁸ to R ²⁵ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group or a heterocyclic ring which may have a substituent, The representative .n ¹ ~n ⁴ represents an integer of 0 to 4 each independently. Further, Ar ¹ to Ar ⁶ may be bonded together to form a ring structure together.)

Images