JP4223898B2 - Electrophotographic photosensitive member and image forming apparatus - Google Patents

Description

The present invention relates to an electrophotographic photoreceptor and an image forming apparatus having excellent wear resistance and excellent electrophotographic characteristics.

  An organic photoreceptor is one of the elements of an image forming apparatus. A typical example of the organic photoreceptor is a laminated photoreceptor in which a charge generation layer and a charge transport layer are sequentially laminated on a conductive substrate. The charge transport layer is formed of a low molecular charge transport material and a binder resin, and many aromatic polycarbonate resins have been proposed as the binder resin.

  Polycarbonate resin has high impact resistance and good light transmittance in the visible range, and is therefore suitable as a charge transporting layer as the outermost layer of the photoreceptor. A low molecular charge transport material may be added to the charge transport layer for the purpose of imparting transportability of charge carriers generated in the charge generation layer. In general, low molecular charge transport materials are known to reduce the mechanical strength of polycarbonate resins suitable for charge transport layers, and the decrease in strength may cause abrasion deterioration, scratches, cracks, etc. of the photoreceptor. This is considered to impair the durability of the photoreceptor.

  The durability of the photosensitive member is also closely related to the energy saving viewpoint of the electrophotographic apparatus. In general, a photoreceptor in an electrophotographic apparatus is affected by various external factors during the developing process, and one of them is toner. In recent years, toners may contain additives such as silica fine particles for the purpose of ensuring fluidity. Since the hardness of silica is extremely higher than that of the surface of the photoreceptor, it is considered to cause scratches and abrasion due to scratching.

On the other hand, for the purpose of avoiding a decrease in durability of the photoreceptor, studies have been made on a polymer charge transport material that does not use a low molecular charge transport material. Patent Document 1 proposes using a polymer charge transport material to improve wear resistance. However, the purification of the polymer charge transport material is complicated and difficult as compared with the handling of the low molecular charge transport material, and it is difficult to develop stable electrophotographic characteristics, so that it has not been put into practical use.
JP 2001-72756 A

  As described above, the conventional technique has a problem in that the wear resistance due to the inclusion of the low molecular charge transport material is greatly reduced. Another problem is that good photographic characteristics cannot be obtained due to the acquisition of wear resistance. The present invention has been made in view of the above-described prior art, and is an electrophotographic photoreceptor excellent in abrasion resistance even in a system in which a low molecular charge transport material is mixed. It is to provide a photoconductor for use.

Electrons that have higher wear resistance, especially scratch resistance than conventional organic photoreceptors, even in systems that contain low molecular charge transport materials by using polycarbonate resin containing specific structural units in the photosensitive layer. It has been found that a photographic photoreceptor can be provided.
That is, the present invention is an invention having the following features [1] to [8].

  [1] General formula (4)

及び一般式（５）

And general formula (5)

で表される構成単位を有し、Ｒ_１は、炭素数１以上６以下の無置換若しくは置換のアルキル基であり、且つ、一般式（４）で表わされる構造単位及び一般式（５）で表わされる構造単位は、それぞれ、カーボネート基を介して連結されたポリカーボネート樹脂を含有した層を有する電子写真感光体。これにより、高い機械的強度を持つポリカーボネート樹脂を含有する電子写真感光体を得ることができる。

R ₁ is an unsubstituted or substituted alkyl group having 1 to 6 carbon atoms , and a structural unit represented by the general formula (4) and the general formula (5) Each of the structural units represented is an electrophotographic photosensitive member having a layer containing a polycarbonate resin linked via a carbonate group . Thereby, an electrophotographic photosensitive member containing a polycarbonate resin having high mechanical strength can be obtained.

  [2] The electrophotographic photosensitive member according to [1], wherein the total molar ratio of the structural units represented by the general formula (4) and / or (5) is 10 mol% or more. Here, “containing 10 mol% or more” means that the total number of structural units represented by the general formula (4) and the general formula (5) is 10 mol% or more with respect to the total number of structural units of the polycarbonate resin. It means to contain. Thereby, an electrophotographic photosensitive member containing a polycarbonate resin having excellent wear resistance can be obtained.

  [3] The electrophotographic photosensitive member according to [1] or [2], wherein the polycarbonate resin has a polystyrene equivalent weight average molecular weight of 30,000 or more. Thereby, it is possible to obtain an electrophotographic photoreceptor containing a polycarbonate resin having sufficient mechanical strength while maintaining the ease of the manufacturing process.

  [4] General formula (6)

で表されるビスフェノール化合物を、ハロゲン化カルボニル化合物又はホスゲン誘導体により重縮合させることにより、一般式（４）

Is polycondensed with a halogenated carbonyl compound or a phosgene derivative to give a general formula (4)

及び一般式（５）

And general formula (5)

で表される構成単位を有し、Ｒ_１は、炭素数１以上６以下の無置換若しくは置換のアルキル基であり、且つ、一般式（１）で表わされる構造単位及び一般式（２）で表わされる構造単位は、それぞれ、カーボネート基を介して連結されたポリカーボネート樹脂を含有した層を有する電子写真感光体。これにより、高度な耐摩耗性を有するポリカーボネート樹脂を含有する電子写真感光体を簡便に得ることが可能となる。

R ₁ is an unsubstituted or substituted alkyl group having 1 to 6 carbon atoms , and a structural unit represented by the general formula (1) and the general formula (2). Each of the structural units represented is an electrophotographic photosensitive member having a layer containing a polycarbonate resin linked via a carbonate group . This makes it possible to easily obtain an electrophotographic photosensitive member containing a polycarbonate resin having high wear resistance.

   [5] The electrophotographic photosensitive member according to any one of [1] to [4], wherein the layer containing the polycarbonate resin is a charge generation layer and / or a charge transport layer. Thereby, a photoconductor having high photographic characteristics and strong mechanical strength can be obtained.

   6. The electrophotographic photosensitive member according to claim 5, wherein the layer containing the polycarbonate resin is a charge generation layer and / or a charge transport layer and a protective layer. As a result, a photoconductor with improved wear resistance can be obtained.

  7. The electrophotographic photosensitive member according to claim 6, wherein the charge transport layer or the protective layer containing the polycarbonate resin is provided on the outermost surface of the photosensitive member. As a result, it is possible to obtain a photoreceptor having improved wear resistance while maintaining photographic characteristics.

  [8] An image forming apparatus using the electrophotographic photosensitive member according to any one of [1] to [7]. Accordingly, it is possible to obtain an image forming apparatus having sufficient mechanical strength and improved durability while maintaining the ease of the manufacturing process.

It can be seen that the electrophotographic photoreceptor of the present invention has the same electrophotographic characteristics as those of conventional photoreceptors, but also has high wear resistance even in a low molecular charge transport material mixed system.
In particular, the wear resistance of the CS-10 wear wheel representing scratch wear characteristics is superior to that of conventional photoreceptors, and there is little wear due to scratches in the electrophotographic process with many toner external additives, and it has a long life. A photoreceptor can be provided.

  Details of the present invention will be described below.

(Polycarbonate resin in the present invention)
The polycarbonate resin used in the present invention is a polycarbonate resin containing at least one structural unit represented by the general formula (4) and / or the general formula (5). In particular, it is a structure obtained by polycondensation with a phosgene derivative using a bisphenol compound represented by the general formula (6) having an asymmetric diphenyl ether structure. This structure has a structure in which the structural units of the general formula (4) and the general formula (5) are arbitrarily mixed. This is due to the asymmetry of the bisphenol body.

  Moreover, you may mix the bisphenol monomer currently used for conventionally well-known polycarbonate resin for manufacture of the polycarbonate resin in this invention.

  The polycarbonate resin composed of the structural unit represented by the general formula (4) and / or the general formula (5) is excellent in wear resistance and also in wear resistance when a low molecular charge transport material is mixed. It is possible to provide an electrophotographic photosensitive member that exhibits maximum and has excellent wear resistance.

(Outline of the production method of polycarbonate resin)
The polycarbonate resin used in the present invention can be produced by a method similar to the polymerization of bisphenol and a carbonic acid derivative known as a conventional method for producing a polycarbonate resin. That is, using a diol represented by the general formula (6), (i) a transesterification method with bisaryl carbonate, (ii) a solution or interfacial polymerization method with a halogenated carbonyl compound such as phosgene, or (iii) It is produced by a method using chloroformate such as bischloroformate derived from diol.

(Transesterification method)
In the transesterification method, a diol and bisaryl carbonate are mixed in the presence of an inert gas, and are usually reacted at 120 to 350 ° C. under reduced pressure. The degree of vacuum is changed stepwise, and finally the phenols produced are distilled out of the system at 1 mmHg or less. The reaction time is usually about 1 to 4 hours. Moreover, you may add antioxidant as needed. Examples of the bisaryl carbonate include diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, and dinaphthyl carbonate.

(Solution polymerization and phosgene derivatives)
In the case of solution polymerization, the diol is dissolved in a solvent, a deoxidizing agent is added, and bischloroformate, phosgene, or a phosgene multimer is added thereto. As the deoxidizer, tertiary amines such as trimethylamine, triethylamine, tripropylamine, and pyridine are used. As the solvent used in the reaction, for example, halogenated hydrocarbons such as dichloromethane, dichloroethane, trichloroethane, tetrachloroethane, trichloroethylene, and chloroform, and cyclic ether solvents such as tetrahydrofuran and dioxane, and pyridine are preferable. The reaction temperature is usually 0 to 40 ° C., and the reaction time is several minutes to 5 hours.

(Interfacial polymerization and phosgene derivatives)
When interfacial polymerization is carried out in a method using a carbonyl halide compound or chloroformate, between two phases of an alkaline aqueous solution of diol and an organic solvent which is substantially insoluble in water and dissolves polycarbonate. The reaction is carried out in the presence of a carbonic acid derivative and a catalyst. At this time, a polycarbonate having a narrow molecular weight distribution can be obtained in a short time by emulsifying the reaction medium by high-speed stirring or addition of an emulsifying substance. The base used in the alkaline aqueous solution is an alkali metal or an alkaline earth metal, and is usually a hydroxide such as sodium hydroxide, potassium hydroxide or calcium hydroxide, sodium carbonate, potassium carbonate, calcium carbonate, sodium hydrogen carbonate or the like. Carbonates and the like. These bases may be used alone or in combination. A preferred base is sodium hydroxide or potassium hydroxide. The water used is preferably distilled water or ion exchange water. Examples of the organic solvent include aliphatic halogenated hydrocarbons such as dichloromethane, 1,2-dichloroethane, 1,2-dichloroethylene, trichloroethane, tetrachloroethane, and dichloropropane, aromatic halogenated hydrocarbons such as chlorobenzene and dichlorobenzene, or , A mixture of them. Further, an organic solvent in which aromatic hydrocarbons such as toluene, xylene, and ethylbenzene, and aliphatic hydrocarbons such as hexane and cyclohexane are mixed with them may be used. The organic solvent is preferably an aliphatic halogenated hydrocarbon or an aromatic halogenated hydrocarbon, more preferably dichloromethane or chlorobenzene.

  The carbonyl halide compound or phosgene derivative includes, in addition to phosgene, trichloromethyl chloroformate which is a dimer of phosgene and bis (trichloromethyl) carbonate which is a trimer of phosgene. Also useful are carbonyl halide compounds derived from halogens other than chlorine, such as carbonyl bromide, carbonyl iodide, and carbonyl fluoride. These known production methods are described, for example, in a polycarbonate resin handbook (editor: Seiichi Honma, published by Nikkan Kogyo Shimbun).

(Copolymer)
The polycarbonate resin used in the present invention can be used as a copolymer by selecting an appropriate polymerization operation. For example, a random copolymer can be obtained by uniformly mixing the diol represented by the general formula (6) and the diol used in a conventionally known polycarbonate resin from the beginning and performing a condensation reaction with phosgene. . A random block copolymer can be obtained by adding several kinds of diols during the reaction. Moreover, an alternating copolymer can be obtained by deriving a bischloroformate from a diol and conducting a condensation reaction. In the condensation reaction between these bischloroformate and diol, a random alternating copolymer can be obtained by using a plurality of bischloroformate and diol.

(Diol)
The following can be mentioned as diol preferably used as a copolymerization monomer. Bis (4-hydroxyphenyl) methane, bis (2-methyl-4-hydroxyphenyl) methane, bis (3-methyl-4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1, 2-bis (4-hydroxyphenyl) ethane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,3 -Bis (4-hydroxyphenyl) -1,1-dimethylpropane, 2,2-bis (4-hydroxyphenyl) propane, 2- (4-hydroxyphenyl) -2- (3-hydroxyphenyl) propane, 1, 1-bis (4-hydroxyphenyl) -2-methylpropane, 2,2-bis (4-hydroxyphenyl) Butane, 1,1-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2, 2-bis (4-hydroxyphenyl) hexane, 4,4-bis (4-hydroxyphenyl) heptane, 2,2-bis (4-hydroxyphenyl) nonane, bis (3,5-dimethyl-4-hydroxyphenyl) Methane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3-isopropyl-4-hydroxyphenyl) propane, 2,2-bis (3-sec-butyl-4-) Hydroxyphenyl) propane, 2,2-bis (3-tert-butyl-4-hydroxyphenyl) propane, 2,2-bis (3-cyclohex) 4-hydroxyphenyl) propane, 2,2-bis (3-allyl-4-hydroxyphenyl) propane, 2,2-bis (3-phenyl-4-hydroxyphenyl) propane, 2,2-bis (3 , 5-dimethyl-4-hydroxyphenyl) propane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane, 2, 2-bis (3-bromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 1 , 1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (3- Methyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (3,5-dichloro-4-hydroxyphenyl) cyclohexane, 1,1 -Bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) cycloheptane, 2,2-bis (4-hydroxyphenyl) norbornane, 2,2-bis (4-hydroxyphenyl) adamantane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, ethylene glycol bis (4-hydroxyphenyl) ether, 1,3-bis (4- Hydroxyphenoxy) benzene, 1,4-bis (3-hydroxyphenyl) Noxy) benzene, 4,4′-dihydroxydiphenyl sulfide, 3,3′-dimethyl-4,4′-dihydroxydiphenyl sulfide, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxyphenyl sulfide 4,4′-dihydroxydiphenyl sulfoxide, 3,3′-dimethyl-4,4′-dihydroxyphenyl sulfoxide, 4,4′-dihydroxydiphenyl sulfone, 3,3′-dimethyl-4,4′-dihydroxydiphenyl sulfone 3,3′-diphenyl-4,4′-dihydroxydiphenylsulfone, 3,3′-dichloro-4,4′-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) ketone, bis (3-methyl-4- Hydroxyphenyl) ketone, 3,3,3 ′, 3′-tetramethyl-6,6′-dihydroxyspi Biindane, 3,3 ′, 4,4′-tetrahydro-4,4,4 ′, 4′-tetramethyl-2,2′-spirobi (2H-1-benzopyran) -7,7′-diol, trans- 2,3-bis (4-hydroxyphenyl) -2-butene, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxyphenyl) xanthene, 1,6-bis (4- Hydroxyphenyl) -1,6-hexanedione, α, α, α ′, α′-tetramethyl-α, α′-bis (4-hydroxyphenyl) -p-xylene, α, α, α ′, α ′ Tetramethyl-α, α′-bis (4-hydroxyphenyl) -m-xylene, 2,6-dihydroxybenzo-p-dioxane, 2,6-dihydroxythianthrene, 2,7-dihydroxyphenoxathiin, 9 , 10-dimethyl-2 7-dihydroxyphenazine, 3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, 4,4'-dihydroxybiphenyl, 1,4-dihydroxynaphthalene, 2,7-dihydroxypyrene, hydroquinone, norosin, 4-hydroxyphenyl -4-hydroxybenzoate, ethylene glycol-bis (4-hydroxybenzoate), diethylene glycol-bis (4-hydroxybenzoate), triethylene glycol-bis (4-hydroxybenzoate), p-phenylene-bis (4-hydroxybenzoate) 1,6-bis (4-hydroxybenzoyloxy) -1H, 1H, 6H, 6H-perfluorohexane, 1,4-bis (4-hydroxybenzoyloxy) -1H, 1H, 4H, 4 - perfluorobutane, 1,3-bis (4-hydroxyphenyl) tetramethyl disiloxane, phenol-modified silicone oils. Moreover, the aromatic diol compound containing the ester bond manufactured by reaction of 2 mol of diols and 1 mol of isophthaloyl chloride or terephthaloyl chloride can also be used.

  Further, an antioxidant such as hydrosulfite may be added in order to prevent oxidation of the diol in the alkaline aqueous solution. The reaction temperature is usually 0 to 40 ° C., the reaction time is several minutes to 5 hours, and the pH during the reaction is preferably kept at 10 or more.

(catalyst)
Polycarbonate-forming catalysts used in the production of polycarbonate include tertiary amines, quaternary ammonium salts, tertiary phosphines, quaternary phosphonium salts, nitrogen-containing heterocyclic compounds and salts thereof, imino ethers and salts thereof, amides A compound having a group or the like can be used. Specific examples of the polycarbonate formation catalyst include trimethylamine, triethylamine, tri-n-propylamine, tri-n-hexylamine, N, N, N ′, N′-tetramethyl-1,4-tetramethylenediamine, 4-pyrroline. Dinopyridine, N, N'-dimethylpiperazine, N-ethylpiperidine, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, tetramethylammonium chloride, tetraethylammonium bromide, phenyltriethylammonium chloride, triethylphosphine, triphenylphosphine, diphenylbutylphosphine , Tetra (hydroxymethyl) phosphonium chloride, benzyltriethylphosphonium chloride, benzyltriphenylphosphonium chloride Id, 4-methylpyridine, 1-methylimidazole, 1,2-dimethylimidazole, 3-methylpyridazine, 4,6-dimethylpyrimidine, 1-cyclohexyl-3,5-dimethylpyrazole, 2,3,5,6- Tetramethylpyrazine and the like. These polycarbonate forming catalysts may be used alone or in combination. The polycarbonate-forming catalyst is preferably a tertiary amine, more preferably a tertiary amine having 3 to 30 carbon atoms, and particularly preferably triethylamine. These catalysts can be added before and / or after adding a carbonic acid derivative such as phosgene or bischloroformate to the reaction system.

(Molecular weight regulator)
In all the above polymerization operations, it is desirable to use a terminal terminator as a molecular weight regulator for the purpose of regulating the molecular weight. As a result, a substituent derived from the terminal terminator is introduced into the terminal of the obtained polycarbonate resin, but there is no problem in the present invention. The terminal terminator used is a monovalent aromatic hydroxy compound, a haloformate derivative of a monovalent aromatic hydroxy compound, a monovalent carboxylic acid, a halide derivative of a monovalent carboxylic acid, or the like. Monovalent aromatic hydroxy compounds include, for example, phenol, p-cresol, o-ethylphenol, p-ethylphenol, p-isopropylphenol, p-tert-butylphenol, p-cumylphenol, p-cyclohexylphenol, p -Octylphenol, p-nonylphenol, 2,4-xylenol, p-methoxyphenol, p-hexyloxyphenol, p-decyloxyphenol, o-chlorophenol, m-chlorophenol, p-chlorophenol, p-bromophenol, Pentabromophenol, pentachlorophenol, p-phenylphenol, p-isopropenylphenol, 2,4-di (1'-methyl-1'-phenylethyl) phenol, β-naphthol, α-naphthol, p- (2 ′, 4 ', 4'-trimethylchromanyl) phenol, phenols such as 2- (4'-methoxyphenyl) -2- (4 "-hydroxyphenyl) propane, or alkali metal salts and alkaline earth metal salts thereof. The haloformate derivative of a monovalent aromatic hydroxy compound is the above-described haloformate derivative of a monovalent aromatic hydroxy compound.

  Examples of monovalent carboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, 2,2-dimethylpropionic acid, 3-methylbutyric acid, 3,3-dimethylbutyric acid, 4- Fatty acids such as methyl valeric acid, 3,3-dimethyl valeric acid, 4-methyl caproic acid, 3,5-dimethyl caproic acid, phenoxyacetic acid, or alkali metal salts and alkaline earth metal salts thereof, benzoic acid, p- Benzoic acids such as methylbenzoic acid, p-tert-butylbenzoic acid, p-butoxybenzoic acid, p-octyloxybenzoic acid, p-phenylbenzoic acid, p-benzylbenzoic acid, p-chlorobenzoic acid or their alkalis Metal salts and alkaline earth metal salts. Examples of the monovalent carboxylic acid halide derivative include the above-described monovalent carboxylic acid halide derivatives. These end-capping agents can be arbitrarily adjusted in molecular weight by adding them before and during the reaction in the course of the polymerization operation. Further, these end-capping agents can also be used as end-group protecting agents, and can be added after the completion of the polymerization reaction to protect the end groups and add various functions. These terminal blocking agents may be used alone or in combination. The end-capping agent is preferably a monovalent aromatic hydroxy compound, more preferably phenol, p-tert-butylphenol, p-cumylphenol or phenyl chloroformate.

(Branching agent)
Also, a small amount of a branching agent can be added during the polymerization in order to improve the mechanical properties. The amount used for the reaction system is generally 5% by weight or less, preferably 2% by weight or less. If it is 5% by weight or more, the reaction system gels and synthesis itself cannot be performed. On the other hand, when the content is 2 to 5% by weight, the mechanical properties are lowered depending on the degree of branching in the reaction product, which affects the effects such as wear resistance in the present invention. The branching agent used is a compound having three or more (same or different) reactive groups selected from an aromatic hydroxy group, a haloformate group, a carboxylic acid group, a carboxylic acid halide group, or an active halogen atom. is there. Specific examples of the branching agent include phloroglucinol, 4,6-dimethyl-2,4,6-tris (4'-hydroxyphenyl) -2-heptene, 4,6-dimethyl-2,4,6-tris. (4'-hydroxyphenyl) heptane, 1,3,5-tris (4'-hydroxyphenyl) benzene, 1,1,1-tris (4'-hydroxyphenyl) ethane, 1,1,2-tris (4 '-Hydroxyphenyl) propane, α, α, α'-tris (4'-hydroxyphenyl) -1-ethyl-4-isopropylbenzene, 2,4-bis [α-methyl-α- (4'-hydroxyphenyl) ) Ethyl] phenol, 2- (4′-hydroxyphenyl) -2- (2 ″, 4 ″ -dihydroxyphenyl) propane, tris (4-hydroxyphenyl) phosphine, 1,1,4,4- Tetrakis (4′-hydroxyphenyl) cyclohexane, 2,2-bis [4 ′, 4′-bis (4 ″ -hydroxyphenyl) cyclohexyl] propane, α, α, α ′, α′-tetrakis (4′-hydroxy) Phenyl) -1,4-diethylbenzene, 2,2,5,5-tetrakis (4'-hydroxyphenyl) hexane, 1,1,2,3-tetrakis (4'-hydroxyphenyl) propane, 1,4-bis (4 ′, 4 ″ -dihydroxytriphenylmethyl) benzene, 3,3 ′, 5,5′-tetrahydroxydiphenyl ether, 3,5-dihydroxybenzoic acid, 3,5-bis (chlorocarbonyloxy) benzoic acid, 4 -Hydroxyisophthalic acid, 4-chlorocarbonyloxyisophthalic acid, 5-hydroxyphthalic acid, 5-chlorocarbonylo Shifutaru acid, trimesic acid trichloride, a cyanuric acid chloride or the like. These branching agents may be used alone or in combination.

(Other additives)
The polycarbonate resin obtained as described above is used after removing impurities such as catalyst and antioxidant used during polymerization, unreacted diol and terminal terminator, and inorganic salt generated during polymerization. Is done. These purification operations can also use known methods described in the previous polycarbonate resin handbook (editor: Seiichi Honma, issue: Nikkan Kogyo Shimbun). These known methods include: a multistage extraction method; a method using an orifice tower stirring tank; a method in which an aqueous dispersion phase and a water-in-oil dispersion phase are formed and combined with centrifugal separation; a cationic emulsifier or dispersant and an organic anion. Separation using an ion exchange resin; Separation using an organic, inorganic, hydrophobic or polytetrafluoroethylene filter medium layer; Separation using diatomaceous earth; Separation using gel cellulose A method combining high voltage treatment and static separation; a method of freezing and solidification; or a method using salt, gluconic acid, butanol, isobutanol, or n-heptane. In addition, additives such as an antioxidant, a light stabilizer, a heat stabilizer, a lubricant, and a plasticizer can be added to the aromatic polycarbonate resin produced according to the above method, if necessary.

(Substituent)
The substituted or unsubstituted alkyl group having 1 to 6 carbon atoms used in the description of the present invention is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, and these alkyl groups are further fluorine atoms. , A cyano group, a phenyl group, or a phenyl group substituted with a halogen atom or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms. Specifically, methyl group, ethyl group, n-propyl group, i-propyl group, t-butyl group, s-butyl group, n-butyl group, i-butyl group, trifluoromethyl group, 2-cyanoethyl group Benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, cyclopentyl group, cyclohexyl group and the like. Preferably, it is a methyl group.

  The substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms represents an alkoxy group having the above substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and specific examples thereof include a methoxy group, an ethoxy group, n -Propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, s-butoxy group, t-butoxy group, 2-hydroxyethoxy group, 2-cyanoethoxy group, benzyloxy group, 4-methylbenzyloxy Group, trifluoromethoxy group and the like.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  A substituted or unsubstituted aryl group is a phenyl group, naphthyl group, biphenylyl group, terphenylyl group, pyrenyl group, fluorenyl group, 9,9-dimethyl-2-fluorenyl group, azulenyl group, anthryl group, triphenylenyl group, chrysenyl group Fluorenylidenephenyl group, 5H-dibenzo [a, d] cycloheptenylidenephenyl group, thienyl group, benzothienyl group, furyl group, benzofuranyl group, carbazolyl group, pyridinyl group, pyrrolidyl group, oxazolyl group, etc. These may have the above-described substituted or unsubstituted alkyl group, the alkoxy group having the above-described substituted or unsubstituted alkyl group, and a halogen atom as a substituent.

(Mechanical characteristics etc.)
In the present invention, the polycarbonate resin containing the general formulas (4) and (5) as a structural unit is used. However, it is also possible to use a resin made of a copolymer containing structural units other than (4) and (5). it can. When the copolymer is used, the total number of structural units represented by the general formula (4) and the general formula (5) is preferably 10 mol% or more based on the total number of structural units of the polycarbonate resin. More preferably, it is contained in an amount of 30 mol% or more. Furthermore, it is still more preferable to contain 50 mol% or more. In the resin of the present invention, the excellent wear resistance is expressed by the structural units represented by the general formula (4) and the general formula (5). Therefore, when these concentrations are lowered, the effect is reduced.

  The preferred molecular weight of the polycarbonate resin used in the present invention is 30000-300000 in terms of polystyrene-converted weight average molecular weight, more preferably 70000-250,000. If the molecular weight is too small, the mechanical strength becomes weak and the practicality is poor, such as cracking during film formation. On the other hand, if the molecular weight is too large, the solution viscosity becomes high and coating becomes difficult.

(Photoreceptor configuration)
Cross-sectional views of the photoconductor of the present invention are shown in FIG. 1, FIG. 2, FIG. 3, and FIG. The photoreceptor of the present invention contains a specific polycarbonate resin in the photosensitive layers 12, 22, 32, and 42. Depending on the application method, the photoreceptors shown in FIGS. 1, 2, 3, and 4 are used. Can be used as indicated.

(Figure 1)
The photoreceptor in FIG. 1 has a structure in which a charge transport medium 14 containing a charge generating substance C is configured as a photosensitive layer 12 and is disposed on a conductive support 11. In other words, the conductive layer is formed by dispersing the charge generation material C in the polycarbonate resin mixed with the low molecular charge transport agent or the charge transport medium 14 obtained by further adding a binder to the polycarbonate resin and forming the photosensitive layer 12. It is placed on the body 11. The polycarbonate resin mixed with the low-molecular charge transport agent here forms a charge transport medium alone or in combination with a binder. On the other hand, the charge generation material C (charge generation material such as an inorganic or organic pigment) generates a charge carrier. The charge transport medium 14 is mainly responsible for receiving charge carriers generated by the charge generating substance C and transporting them. In this photoreceptor, the basic condition is that the charge generation material C and the polycarbonate resin mixed with the low molecular charge transport agent do not overlap each other with respect to the absorption wavelength region in the visible region. This is because in order to efficiently generate charge carriers in the charge generation material C, it is necessary to transmit light to the surface of the charge generation material. The polycarbonate resin mixed with the low molecular charge transport agent used in the present invention has almost no absorption at a wavelength of 600 nm or more, and generally absorbs light on the short wavelength side in the visible region. On the other hand, most of the charge generation material C absorbs light in the visible to near-infrared region, and generally has absorption at 400 to 750 nm for disazu pigments and 400 to 800 nm for phthalocyanine pigments. is doing. When these charge generating material and charge transporting material are combined, each has a feature that works particularly effectively in order to exhibit its function.

  To prepare the photoreceptor shown in FIG. 1, fine particles of the charge generating material C are dispersed in a solution in which a low molecular charge transport material, polycarbonate resin or binder is dissolved, and this is coated on the conductive support 11 and dried. Thus, the photosensitive layer 12 may be formed.

  The thickness of the photosensitive layer 12 is 3 to 50 μm, preferably 5 to 40 μm. The amount of the polycarbonate resin in the photosensitive layer 12 is preferably 20 to 70% by weight, the amount of the low molecular charge transport material is 30 to 70% by weight, and the amount of the charge generating substance C in the photosensitive layer 12 is 0.1 to 50% by weight, preferably 1 to 20% by weight.

  As the conductive support 11, a metal plate or a metal foil such as aluminum, a plastic film on which a metal such as aluminum is vapor-deposited, or paper subjected to a conductive treatment is used, and any of the following conductive supports (21, 31 This also applies to 41 and 41).

(Figure 2)
2 is a charge transport layer 24 containing a polycarbonate resin in which a charge generation layer 23 mainly composed of a charge generation material C and a low molecular charge transport agent having a charge transport capability are mixed on a conductive support 21. In which a photosensitive layer 22 is provided. In this photoreceptor, light transmitted through the charge transport layer 24 reaches the charge generation layer 23, and charge carriers are generated in the region, and the charge carriers are transferred to the charge transport layer 24 and transported. Such a mechanism is the same as that described in the photoconductor shown in FIG.

  The charge transport layer 24 is formed by using only the polycarbonate resin mixed with the low molecular charge transport agent used in the present invention, or in combination with the binder. In order to increase the charge generation efficiency, the charge generation layer 23 may contain a polycarbonate resin mixed with the low molecular charge transport agent used in the present invention. Several kinds of azo-based charge generation materials are known to be able to generate charges efficiently at the contact point with the charge transporting material. In the present invention, a small amount of charge transport material is included in the charge generation layer. By mixing the materials, it is possible to impart further improvement in charge generation efficiency. The same applies to photosensitive layers 32 and 42 described later.

  In order to produce the photoreceptor shown in FIG. 2, the charge generating material C is vacuum-deposited on the conductive support 21 or, if necessary, fine particles of the charge generating material C in a suitable solvent in which a binder is dissolved. After applying and drying the dispersion liquid, a charge generation layer 23 is formed by performing surface finishing and film thickness adjustment by a method such as buffing, if necessary, to form a low molecular charge transport material, polycarbonate The charge transport layer 24 may be formed by applying and drying a solution in which a resin or a binder is dissolved.

  Here, the charge generation material used for forming the charge generation layer 24 is the same as the description of the photosensitive layer 12 described above.

(Figure 3)
The photoconductor in FIG. 3 is obtained by further providing a second charge transport layer 324 on the charge transport layer 314. The second charge transport layer 324 may be referred to as a protective layer. This is because it is used on the outermost surface of the photoconductor with the intention of imparting functions such as wear resistance. In this case, the protective layer can be regarded as a part of the charge transport layer.

  In this configuration, the second charge transport layer 324 is formed on the charge transport layer 314 using the polycarbonate resin used in the present invention or a polycarbonate resin containing a binder. Of course, a low molecular charge transport material may be added. At that time, the content of the low molecular charge transport material is preferably 60% by weight or less. When it exceeds 60% by weight, the mechanical properties are remarkably deteriorated, making it difficult to use practically. Further, it is more preferable that a low molecular charge transport material is mixed in the charge transport layer 314 at a high concentration and not used in the second charge transport layer 324 or is used at a low concentration. For example, when the thickness of the second charge transport layer 324 is 2 μm or less, sufficient electrophotographic characteristics can be obtained without adding a low molecular charge transport material. In order to obtain sufficient mechanical properties, the thickness of the second charge transport layer is preferably about 5 to 10 μm. In this case, it is preferable to contain 60% by weight or less of a low molecular charge transport material. A protective layer may be similarly provided on the photosensitive layer 12 shown in FIG.

  In order to produce the photoreceptor shown in FIG. 3, the polycarbonate resin used in the present invention alone or a polycarbonate resin containing a binder on the photoreceptor shown in FIG. Then, it is dissolved and applied, and dried to form a second charge transport layer (protective layer) 324. The thickness of the second charge transport layer (protective layer) is preferably 0.15 to 10 μm. The amount of the polycarbonate resin used in the present invention in the second charge transport layer (protective layer) 324 is preferably 20 to 100% by weight.

  The thickness of the charge generation layer 33 is 5 μm or less, preferably 2 μm or less, and the thickness of the charge transport layer 314 is 3 to 50 μm, preferably 5 to 40 μm. In the charge generation layer 33 in which the fine particles of the charge generation layer material C are dispersed in the binder, the proportion of the fine particles of the charge generation material C in the charge generation layer 33 is 10 to 100% by weight, preferably 50 to 100%. It is about wt%. The amount of the polycarbonate resin in the charge transport layer 314 is 20 to 70% by weight.

(Fig. 4)
The photoreceptor in FIG. 4 is obtained by reversing the stacking order of the charge generation layer 23 of FIG. 2 and the charge transport layer 24 containing the low molecular charge transport agent mixed polycarbonate resin, and the mechanism of generation and transport of the charge carriers. Can be done as described above. In this case, the protective layer 45 is provided on the charge generation layer 43 in consideration of mechanical strength. The polycarbonate resin used in FIG. 4 can be used for the charge transport layer 44, but can also be used as a binder for the protective layer 45 by taking advantage of its excellent mechanical wear resistance.

  In order to produce the photoreceptor shown in FIG. 4, a solution in which a polycarbonate resin as a binder or a polycarbonate resin containing a binder is used and dissolved together with a low molecular charge transport material is applied on the conductive support 41. After forming the charge transport layer 44 by drying, charge dispersion is generated by applying and drying a dispersion in which fine particles of the charge generation layer material C are dispersed in a solvent in which a binder is dissolved, if necessary. Layer 43 is formed. The amount ratio and the film thickness of the charge generation layer 43 or the charge transport layer 44 are the same as those described in FIG.

  A protective layer 6 containing the polycarbonate resin used in the present invention is formed on the charge generation layer 43 of the photoreceptor thus obtained, and the photoreceptor shown in FIG. 4 is produced. The amount of the polycarbonate resin in the protective layer 45 is 20 to 100% by weight.

(Other photoconductor components)
The photoreceptor includes a conductive support (11, 21, 31, and 41), a photosensitive layer (12, 22, 32, and 42), a charge generation layer (23, 33, and 43), a charge transport medium or It is composed of a charge transport layer (14, 24, 314 and 324, and 44) and a protective layer (45). Furthermore, if necessary, an adhesive layer or a barrier layer can be provided between the conductive support and the photosensitive layer for the purpose of maintaining the charging property. Materials used for these layers include polyamide, nitrocellulose, aluminum oxide, titanium oxide and the like, and the film thickness is preferably 10 μm or less. Further, it is more preferable to provide a film thickness of 2 to 5 μm for the purpose of improving the shape depending on the material of the conductive support.

  Next, examples of materials suitable for the use of each of the photosensitive member components will be described.

(Low molecular charge transport material)
Examples of the low molecular charge transport material include oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazoline derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, and benzidine. Compound, pyrazoline derivative, stilbene compound, amine derivative, oxazolone derivative, benzothiazole derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, poly-N-vinylcarbazole, poly-1-vinylpyrene Conventionally known materials such as poly-9-vinylanthracene can be used.

(Charge generating material)
As the charge generation material C, conventionally known inorganic materials and organic materials described later can be used. The inorganic material and the organic material may be used alone or in combination of two or more.

  Examples of the inorganic material include selenium, selenium-tellurium, cadmium sulfide, cadmium sulfide-selenium, and α-silicon.

  Examples of the organic material include C.I. Pigment Blue 25 (Color Index CI21180), C.I. Pigment Red 41 (CI21200), C.I. Acid Red 52 (CI45100), C.I. No. 53-95033), an azo pigment having a distyrylbenzene skeleton (JP-A-53-133445), an azo pigment having a triphenylamine skeleton (described in JP-A-53-132347), An azo pigment having a dibenzothiophene skeleton (described in JP-A No. 54-21728), an azo pigment having an oxadiazole skeleton (described in JP-A No. 54-12742), an azo pigment having a fluorenone skeleton (JP-A No. 54-21728) Sho 54-22834 Azo pigments having a bis-stilbene skeleton (described in JP-A No. 54-17733), azo pigments having a distyryloxadiazole skeleton (described in JP-A No. 54-2129), distyryl Azo pigments such as azo pigments having a carbazole skeleton (described in JP-A-54-14967), for example, phthalocyanine pigments such as C.I. Pigment Blue 16 (CI 74100), such as C. I.But Brown 5 (CI73410), C.I. CI indigo pigments such as CI73030) and perylene pigments such as Argo scarlet B (manufactured by Bayer) and Indence Scarlet R (manufactured by Bayer).

(Phthalocyanine)
Among the above charge generating materials, a highly sensitive and highly durable photoreceptor can be obtained by combining with a phthalocyanine pigment in particular. The phthalocyanine pigment is a compound having a phthalocyanine skeleton represented by the general formula (7), and M (center metal) includes a metal and a nonmetal (hydrogen) element described later.

  General formula (7)

Ｍは、Ｈ、Ｌｉ、Ｂｅ、Ｎａ、Ｍｇ、Ａｌ、Ｓｉ、Ｋ、Ｃａ、Ｓｃ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｇａ、Ｇｅ、Ｙ、Ｚｒ、Ｎｂ、Ｍｏ、Ｔｃ、Ｒｕ、Ｒｈ、Ｐｄ、Ａｇ、Ｃｄ、Ｉｎ、Ｓｎ、Ｓｂ、Ｂａ、Ｈｆ、Ｔａ、Ｗ、Ｒｅ、Ｏｓ、Ｉｒ、Ｐｔ、Ａｕ、Ｈｇ、Ｔｌ、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、Ｔｈ、Ｐａ、Ｕ、Ｎｐ、Ａｍ等の単体、もしくは酸化物、塩化物、フッ化物、水酸化物、臭化物などの２種以上の元素からなる。中心金属は、これらの元素に限定されるものではない。本発明におけるフタロシアニン骨格を有する電荷発生物質とは、少なくとも一般式（7）の基本骨格を有していればよく、２量体、３量体など多量体構造を持つもの、さらに高次の高分子構造を持つものでも構わない。また基本骨格に様々な置換基があるものでもかまわない。

M is H, Li, Be, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Nb , Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, La, Ce, Pr, Nd , Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, Pa, U, Np, Am, etc., or an oxide, chloride, fluoride, hydroxide, Consists of two or more elements such as bromide. The central metal is not limited to these elements. The charge generation material having a phthalocyanine skeleton in the present invention may have at least the basic skeleton of the general formula (7), and those having a multimeric structure such as a dimer and a trimer, It may have a molecular structure. Also, the basic skeleton may have various substituents.

  Of these various phthalocyanines, metal-free phthalocyanine having H and oxotitanium phthalocyanine having TiO as a central metal are particularly preferable in terms of photoreceptor characteristics.

  These phthalocyanines are also known to have various crystal systems. For example, oxotitanium phthalocyanine has a polycrystal system such as α, β, γ, m, y type. Even in a phthalocyanine having the same central metal, various characteristics change due to a change in crystal system. A change in the characteristics of the photoreceptor has been reported along with such a change in crystal system (Electrophotographic Society Vol. 29, No. 4 (1990)). Therefore, each phthalocyanine has an optimum crystal system in terms of the characteristics of the photoreceptor, and in particular, for oxotitanium phthalocyanine, a y-type crystal system is desirable.

  The charge generation material C may contain two or more kinds of charge generation materials having a phthalocyanine skeleton. Further, it may be mixed with other charge generating materials. In this case, examples of the charge transport material that can be mixed include the following inorganic materials and organic materials.

  Inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. Amorphous silicon is preferably formed by dangling bonds terminated with hydrogen atoms or halogen atoms, or doped with boron atoms or phosphorus atoms.

  On the other hand, organic materials include azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, azo pigments having a dibenzothiophene skeleton, fluorenone Azo pigment having skeleton, azo pigment having oxadiazole skeleton, azo pigment having bis stilbene skeleton, azo pigment having distyryl oxadiazole skeleton, azo pigment having distyryl carbazole skeleton, perylene pigment, anthraquinone or Polycyclic quinone pigments, quinone imine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, indigoid pigments, bisbenzimidazole pigments, etc. And the like.

  In addition, as binders, condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, vinyl polymers such as polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide are used. Any insulating and adhesive resin can be used. A plasticizer is added to the binder as necessary. Examples of such a plasticizer include halogenated paraffin, dimethylnaphthalene, and dibutyl phthalate. If necessary, additives such as an antioxidant, a light stabilizer, a heat stabilizer, and a lubricant can be added.

  In order to perform copying using the photoreceptor of the present invention, the photosensitive surface is charged and exposed, then developed, and transferred to paper or the like as necessary. The photoreceptor of the present invention has high sensitivity and is excellent in mechanical strength and is extremely useful.

(Non-patent literature)
Polycarbonate resin handbook (editor: Seiichi Honma, published by Nikkan Kogyo Shimbun)
(Non-patent literature)
The Electrophotographic Society of Japan Vol. 29, No. 4 (1990)
(Patent Literature)
JP-A-53-95033 (patent document)
JP-A-53-133445 (Patent Document)
JP-A-53-132347 (patent document)
JP 54-21728 A (Patent Document)
JP 54-12742 A (Patent Document)
JP 54-22834 A (Patent Document)
Japanese Patent Laid-Open No. 54-17733 (Patent Literature)
JP 54-2129 A (Patent Document)
JP 54-14967

  Hereinafter, the present invention will be described by way of examples. Note that the present invention is not limited to the embodiment.

(Material synthesis example)
[Synthesis of bisphenol monomer]
<Synthesis of (3-methyl-4-methoxyphenyl) -4-methoxyphenyl ether>
201.1 g of 5-bromo-2-methoxytoluene, 250 g of 4-methoxyphenol, 31.8 g of copper powder, 333.4 g of potassium carbonate, and 200 ml of orthoxylene are placed in a reaction vessel and stirred at 185 ° C. to 202 ° C. for 3 hours under a nitrogen stream. It was made to react. After cooling, the obtained solid was dissolved by heating in a mixed solvent of 200 ml of toluene and 500 ml of ethyl acetate, filtered through celite, the filtrate was adsorbed with activated clay, and then 2% with 5% aqueous sodium chloride solution. Washed twice. The resulting solution was concentrated and purified with a mixed solvent of toluene and hexane using a silica gel column. 210.5 g of (3-methyl-4-methoxyphenyl) -4-methoxyphenyl ether was obtained as a colorless oil. The yield was 86.2%.

<Synthesis of (3-methyl-4-hydroxyphenyl) -4-hydroxyphenyl ether>
207.8 g of (3-methyl-4-methoxyphenyl) -4-methoxyphenyl ether and 1650 ml of methylene chloride were placed in a reactor and stirred while cooling to −17 ° C. under a nitrogen stream. Thereafter, 1790 mL of 1M boron tribromide methylene chloride solution was added dropwise at 10 mL / min over 3 hours at 0 ° C. to cause the reaction. Then, 500 ml of water was added and extracted with 1500 mL of ethyl acetate. The extract was washed with an aqueous sodium bicarbonate solution and water, and dehydrated by adding magnesium sulfate. Then, it filtered and concentrated and refine | purified with the mixed solvent of toluene and ethyl acetate using the silica gel column. Then, it recrystallized with a mixed solvent of toluene and cyclohexane to obtain 134.4 g of (3-methyl-4-hydroxyphenyl) -4-hydroxyphenyl ether in a colorless crystal state. The yield was 73.1% and the melting point was 115.9-116.8 ° C.

[Synthesis of polycarbonate resin]
(Synthesis Example 1)
4.463 parts of (3-methyl-4-hydroxyphenyl) -4-hydroxyphenyl ether and 0.155 part of 4-tert-butylphenol obtained in the above material synthesis example were put in a container, and 79 parts of water under a nitrogen stream. A solution prepared by dissolving 6.21 parts of sodium hydroxide and 0.248 parts of sodium hydrosulfite was added to the solution, and the mixture was dissolved by stirring and cooled to 7 ° C. Meanwhile, in another reaction vessel, 3.674 parts of bis (trichloromethyl) carbonate, which is a trimer of phosgene, and 51.2 parts of dichloromethane are dissolved with stirring and cooled to 7 ° C. to obtain a phosgene solution. It was. Then, the alkaline solution of the monomer containing the (3-methyl-4-hydroxyphenyl) -4-hydroxyphenyl ether was added to the phosgene solution, and reacted while forming an emulsion with vigorous stirring. After stirring for 15 minutes, 0.01 part of triethylamine was added, and the reaction was stirred at 27 ° C. for 150 minutes.

  After completion of the reaction, the organic layer is taken out, diluted with 50 parts of dichloromethane, washed in order with water and a 2% hydrochloric acid aqueous solution, and finally washed with water, and the conductivity of the aqueous layer after washing becomes 1 μS or less. Confirmed. The obtained organic layer was dropped into isopropyl alcohol to obtain a colorless polycarbonate resin. The yield after filtration and drying was 4.76 parts, and the yield was 95%. The obtained polycarbonate resin No. The structure of 1 is described below. When the molecular weight of this polycarbonate resin was measured by gel permeation chromatography, the polystyrene-reduced molecular weight was 67,000 in terms of number average molecular weight and 152,000 in terms of weight average molecular weight. The glass transition temperature determined from differential scanning calorimetry was 105 ° C. The results of elemental analysis were as follows and agreed with the values calculated from the structural formula.

  Resin No.1

C% H% N%
実測値 ６９．４１ ４．２０ ０．００
計算値 ６９．４２ ４．１６ ０．００

C% H% N%
Actual value 69.41 4.20 0.00
Calculated value 69.42 4.16 0.00

(Synthesis Examples 2 to 4)
Polycarbonate resins Nos. 2 to 4 having different molecular weights were obtained in the same manner as in Synthesis Example 1 except that the amount of 4-tert-butylphenol charged was changed.

Resin No.2
Weight average molecular weight 70100
Glass transition temperature 103 ° C
Resin No. 3
Weight average molecular weight 113000
Glass transition temperature 104 ° C
Resin No. 4
Weight average molecular weight 199300
Glass transition temperature 105 ° C

(Synthesis Example 5)
Resin No. 1 was prepared in the same manner as in Synthesis Example 1 except that 50 mol% of (3-methyl-4-hydroxyphenyl) -4-hydroxyphenyl ether was replaced with 1,1-bis (4-hydroxyphenyl) cyclohexane. 5 was obtained.

  Resin No. 5

重量平均分子量１３５０００
ガラス転移温度 １４５℃

Weight average molecular weight 135000
Glass transition temperature 145 ° C

(Example 1)
A polyamide resin (CM-8000: manufactured by Toray Industries, Inc.) solution dissolved in a methanol / butanol mixed solvent was applied onto an aluminum plate with a doctor blade, and air dried to provide a 0.3 μm intermediate layer. On this, a bisazo compound represented by the following formula is pulverized by a ball mill in a mixed solvent of cyclohexanone and methyl ethyl ketone as a charge generating material, and the resulting dispersion is applied with a doctor blade and naturally dried to obtain a charge of 0.3 μm. A generation layer was formed.

次に、合成例１で得られた樹脂Ｎｏ．１のポリカーボネート樹脂と下記低分子電荷輸送性化合物とを、重量比１０：７でテトラヒドロフランに溶解し、この溶液を、前記電荷発生層上にドクターブレードで塗布し、自然乾燥し、次いで１２０℃で２０分間乾燥して厚さ２０μｍの電荷輸送層を形成して感光体Ｎｏ．１を作製した。かくしてつくられた感光体Ｎｏ．１について市販の静電複写紙試験装置［（株）川口電機製作所製ＳＰ４２８型］を用いて暗所で、−６ｋＶ２０秒間、コロナ放電を行って帯電した後、感光体の表面電位Ｖm （−Ｖ）を測定し、更に２０秒間暗所に放置した後、表面電位Ｖ0 （−Ｖ）を測定した。次いで、タングステンランプ光を感光体表面での照度が４．５ luxになるように照射して、Ｖ0 が１／２になるまでの時間（秒）を求め、露光量Ｅ1/2 (lux・sec)を算出した。その結果を以下に示す。

Next, the resin No. obtained in Synthesis Example 1 was used. 1 polycarbonate resin and the following low-molecular charge transporting compound were dissolved in tetrahydrofuran at a weight ratio of 10: 7, and this solution was applied onto the charge generation layer with a doctor blade, air dried, and then at 120 ° C. After drying for 20 minutes to form a charge transport layer having a thickness of 20 μm, the photoreceptor No. 1 was produced. The photoreceptor No. thus produced was No. 1 was charged by performing a corona discharge for 6 seconds at −6 kV for 20 seconds in the dark using a commercially available electrostatic copying paper testing apparatus [SP428 type manufactured by Kawaguchi Electric Manufacturing Co., Ltd.], and then the surface potential Vm (−V ) And was left in a dark place for 20 seconds, and then the surface potential V0 (-V) was measured. Next, tungsten lamp light is irradiated so that the illuminance on the surface of the photosensitive member becomes 4.5 lux, and the time (seconds) until V0 becomes 1/2 is obtained, and the exposure amount E1 / 2 (lux · sec) is obtained. ) Was calculated. The results are shown below.

また感光体表面を工業規格ＪＩＳ Ｋ ７２０４（１９９５）に従ってテーバー摩耗試験機（東洋精機社製）にてフェルト素材でできたＣＳ−５摩耗輪を使用し、荷重１ｋｇで３０００回転の摩耗試験を行った。また、シリカ粒子含有ゴム素材でできたＣＳ−１０摩耗輪を使用し、荷重２５０ｇで１５００回転の摩耗試験を行なった。これらの試験で得られた摩耗量を表２に合わせて示す。

In addition, the surface of the photoconductor is subjected to a 3000 revolution wear test with a load of 1 kg using a CS-5 wear wheel made of felt material with a Taber abrasion tester (manufactured by Toyo Seiki Co., Ltd.) in accordance with the industrial standard JIS K 7204 (1995). It was. In addition, a wear test of 1500 revolutions was performed at a load of 250 g using a CS-10 wear wheel made of a silica particle-containing rubber material. The amount of wear obtained in these tests is also shown in Table 2.

(Examples 2 to 5)
In Example 1, resin no. 1 except that the polycarbonate resin obtained in Synthesis Examples 2 to 5 was used instead of the polycarbonate resin of No. 1. 2-No. 5 was created and evaluated.

(Comparative Examples 1-6)
In Example 1, resin no. 1 instead of the polycarbonate resin No. 1 Photoreceptor No. 1 was used in the same manner except that polycarbonate resins 1 to 6 were used. 6-No. 11 was created and evaluated.

  Comparative resin No.1

Ｍｗ７６１００
比較樹脂No.２

Mw76100
Comparative resin No.2

Ｍｗ１８０８００
比較樹脂No.３

Mw180800
Comparative resin No.3

Ｍｗ１５１５００
比較樹脂No.４

Mw151500
Comparative resin No.4

Ｍｗ１９０５００
比較樹脂No.５

Mw190500
Comparative resin No. 5

Ｍｗ１０４０００
比較樹脂No.６

Mw104000
Comparative resin No. 6

Ｍｗ７６３００
比較樹脂No.７

Mw76300
Comparative resin No.7

Ｍｗ８１５００

Mw81500

(Comparative Example 7)
In Example 1, resin no. 1 instead of the polycarbonate resin No. 1 An attempt was made to produce a photoreceptor in the same manner using the polycarbonate resin No. 7, but the resin gelled and the photoreceptor could not be produced.

(Example 6)
Resin No. obtained in Synthesis Example 1 No. 1 polycarbonate resin and the above low-molecular charge transporting compound were dissolved in a mixed solvent of tetrahydrofuran and cyclohexanone at a weight ratio of 9: 1 at a weight ratio of 9: 1 to prepare a coating solution. The product was spray-coated on the body, allowed to dry naturally, and then dried at 130 ° C. for 20 minutes to form a protective layer having a thickness of 5 μm. 12 was produced. This was evaluated in the same manner as in Example 1.

(Example 7)
Comparative resin No. A charge transport layer was prepared in the same manner as in Comparative Example 3 except that the polycarbonate resin of No. 3 and the low molecular charge transporting compound were used in a weight ratio of 1: 1. Resin No. A protective layer was formed in the same manner as in Example 6 except that the polycarbonate resin of No. 1 and the low molecular charge transporting compound were used in a weight ratio of 10: 7. 13 was produced. This was evaluated in the same manner as in Example 1.

（実施例の効果）
実施例１〜５及び実施例６〜７が示す通り、本発明の電子写真感光体は従来のものと同等の電子写真特性を有しながら、耐摩耗性は、従来のものに比べて優れた特性を有しており、高耐久な電子写真感光体の提供が可能になる。
特に、引掻き摩耗特性を表すＣＳ−１０摩耗輪での耐摩耗性は、従来の感光体に比べてより優れており、トナー外添剤の多い電子写真プロセスの中でも傷による摩耗が少なく、長寿命の有機感光体を提供が可能である。

(Effect of Example)
As shown in Examples 1 to 5 and Examples 6 to 7, the electrophotographic photosensitive member of the present invention has the same electrophotographic characteristics as those of the conventional ones, but the wear resistance is superior to the conventional ones. It is possible to provide a highly durable electrophotographic photosensitive member having characteristics.
In particular, the wear resistance of the CS-10 wear wheel, which represents the scratch wear characteristics, is superior to that of conventional photoconductors, and is less likely to be worn by scratches in the electrophotographic process with many toner external additives, and has a long service life. It is possible to provide an organic photoreceptor.

  The following points can be considered as the reason why the polycarbonate resin used in the present invention is excellent in wear resistance.

  -The bisphenol body has a diphenyl ether structure, the molecular structure of the ether structure is good, and the appropriate flexibility of the resin can be expressed.

  -Since the resin used in the present invention has a substituent on the benzene ring which is a part of the structural unit, a stable amorphous film can be formed. In the absence of the substituent, it is considered that the contribution to the strong crystallinity rather than the contribution to the formation of the amorphous is large, and the substituent acts in the direction of relaxing the strong crystallinity. In fact, it is known that in the case of a polycarbonate resin having no substituent on the benzene ring, it is known that a transparent amorphous film having strong crystallinity cannot be formed, and this phenomenon is also confirmed in Comparative Example 7 described in this specification. .

  -The polycarbonate resin in this invention is very amorphous, and can form a flexible film | membrane. In a resin that has a diphenyl ether ring and is conventionally known as a substituent that exists symmetrically in the ring, the molecules are easily oriented. On the other hand, the resin used in the present invention has a substituent only on the benzene ring on one side and has very low symmetry. That is, in the polycarbonate resin in the present invention polymerized with a phosgene derivative, the positions of the substituents bonded to the benzene ring, which is a part of the structural unit in the resin, are asymmetric and random, so that the regularity It is thought that this is derived from the fact that the structure becomes low and partial orientation hardly occurs.

  As described above, the high amorphous property derived from the structural unit contributes to the uniform compatibility of the low molecular charge transporting compound, and maintains high mechanical stability without impairing appropriate flexibility.

  As described above, in the resin used in the present invention, there are two orientations of the repeating structural unit, and it is a structure that is usually mixed at random. As a method for obtaining such a structure, as shown in the synthesis example, A method of polycondensation of a bisphenol compound with a phosgene derivative has been confirmed. By using a polycarbonate resin obtained by this method, an electrophotographic photoreceptor excellent in abrasion resistance can be provided.

  Moreover, when Example 5 and Examples 1-4 are compared, it turns out that the direction where a copolymer seed | species is not included is more excellent in abrasion resistance. Therefore, an electrophotographic photosensitive member having a longer life can be provided when the polycarbonate resin comprising the general formula (4) and / or the general formula (5) is used.

  In addition, when the polycarbonate resin used in the present invention is mixed with the high wear resistance and low molecular charge transport compound, the charge transport layer is the outermost surface as a photosensitive member structure in order to utilize the high wear resistance. Excellent electrophotography when applied to a functionally separated electrophotographic photosensitive member structure in which the structure is optimal, the most excellent electrophotographic sensitivity in the past, and the charge generation layer and charge transport layer, which have been in practical use, are stacked in this order. An electrophotographic photosensitive member having both characteristics and high wear resistance can be provided.

  Further, the electrophotographic characteristics or wear resistance can be further improved by forming the charge transport layer in a laminated structure and using the polycarbonate resin used in the present invention on the surface side. For example, as shown in Example 6, a protective layer having a low content of a low-molecular charge transporting compound is laminated thinner than a normal charge transporting layer, thereby further improving wear resistance while having electrophotographic characteristics. I can do it. Further, for example, as shown in Example 7, the content of the low molecular charge transporting compound is increased, a high mobility charge transporting layer is formed, and a protective layer having excellent wear resistance is formed thereon. It is possible to provide an electrophotographic photoreceptor excellent in characteristics and excellent in abrasion resistance.

  Generally, it is known that the abrasion resistance of a polycarbonate resin decreases rapidly as the molecular weight decreases, and it is easily imagined that the same tendency is observed for the polycarbonate resin used in the present invention. As shown in Examples 1 to 4, in the polycarbonate resin used in the present invention, the weight average molecular weight in terms of polystyrene is 30,000 or more, and all show excellent wear resistance, and such a resin should be used. Can provide a long-life electrophotographic photosensitive member.

FIG. 2 is a conceptual diagram of an electrophotographic photosensitive member in which a charge transport medium containing a charge generating substance is provided on a conductive support. FIG. 2 is a conceptual diagram of an electrophotographic photosensitive member in which a charge generation layer containing a charge generation material and a charge transport layer containing a low molecular charge transport agent are sequentially laminated on a conductive support. FIG. 3 is a conceptual diagram of an electrophotographic photoreceptor in which a second charge transport layer is further laminated on the photoreceptor of FIG. 2. FIG. 2 is a conceptual diagram of an electrophotographic photosensitive member in which a charge transport layer and a charge generation layer are sequentially laminated on a conductive support, and a protective layer is further provided.

Explanation of symbols

11 Conductive support
12 Photosensitive layer
14 Charge transport media
21 Conductive support
22 Photosensitive layer
23 Charge generation layer
24 Charge transport layer
31 Conductive support
32 photosensitive layer
33 Charge generation layer
314 Charge transport layer
324 Charge transport layer
41 Conductive support
42 Photosensitive layer
43 Charge generation layer
44 Charge transport layer
45 Protective layer
C charge generation material

Claims (8)

General formula (1)

And general formula (2)

R ₁ is an unsubstituted or substituted alkyl group having 1 to 6 carbon atoms , and a structural unit represented by the general formula (1) and the general formula (2). Each of the structural units represented is an electrophotographic photosensitive member having a layer containing a polycarbonate resin linked via a carbonate group .   2. The electrophotographic photosensitive member according to claim 1, wherein the sum of the molar ratios of the structural units represented by the general formula (1) and / or (2) is 10 mol% or more.   The electrophotographic photosensitive member according to claim 1 or 2, wherein the polycarbonate resin has a polystyrene equivalent weight average molecular weight of 30,000 or more. General formula (3)

The bisphenol compound represented by general formula (1) is polycondensed with a carbonyl halide compound or a phosgene derivative.

And general formula (2)

R ₁ is an unsubstituted or substituted alkyl group having 1 to 6 carbon atoms , and a structural unit represented by the general formula (1) and the general formula (2). Each of the structural units represented is an electrophotographic photosensitive member having a layer containing a polycarbonate resin linked via a carbonate group .   The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein the layer containing the polycarbonate resin is a charge generation layer and / or a charge transport layer.   The electrophotographic photoreceptor according to claim 5, wherein the layer containing the polycarbonate resin is a charge generation layer and / or a charge transport layer and a protective layer.   The electrophotographic photoreceptor according to claim 6, wherein the charge transport layer or the protective layer containing the polycarbonate resin is provided on the outermost surface of the photoreceptor.   An image forming apparatus using the electrophotographic photosensitive member according to claim 1.

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