JP5593817B2 - Electrophotographic photosensitive member, electrophotographic cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photoreceptor excellent in surface slipperiness, electrical characteristics, mechanical properties, particularly abrasion resistance, and an electrophotographic cartridge using the same.

  In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers because of its immediacy and high-quality images. As for the photoreceptor which is the core of the electrophotographic technology, a photoreceptor using an organic photoconductive material having advantages such as easy film formation and easy manufacture has become mainstream. As these organic photoreceptors, a so-called dispersion type photoreceptor in which photoconductive fine powder is dispersed in a binder resin, and a laminate type photoreceptor in which a charge generation layer and a charge transfer layer are laminated are known. Laminated photoconductors can provide highly sensitive photoconductors by combining highly efficient charge generating materials and charge transfer materials, and can provide photoconductors with a wide range of material selection and high safety. Has been developed and put to practical use as the mainstream of photoconductors because of its high productivity and relatively advantageous cost.

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

On the other hand, with the trend toward higher image quality, higher resolution, and higher speed printing, there are increasing demands for improved toner transfer performance, prevention of filming, improved cleaning performance, and prevention of abnormal noise. These are problems that occur between the toner, the cleaning blade, the charging member, and the like that are in contact with the surface of the photoconductor. Improvement of the surface of the photoconductor is required to solve the problem.
In the case of a laminated type photoreceptor, it is the charge transfer layer that is subject to such load and surface property problems. The charge transfer layer is usually composed of a binder resin and a charge transfer material, and since the amount of the charge transfer material doped is considerably large, a sufficient mechanical strength has not been achieved.

  In addition, due to high-speed printing, a material compatible with a high-speed electrophotographic process is demanded. In this case, in addition to high sensitivity and long life, the photosensitive member must have good responsiveness because the time from exposure to development is shortened. It is known that the responsiveness of the photoreceptor is governed by the charge transfer layer, particularly the charge transfer substance, but also greatly changes depending on the binder resin.

  Conventional binder resins for charge transfer layers include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resins. Various thermosetting resins have been used. Among the various binder resins, the polycarbonate resin has relatively excellent performance, and various polycarbonate resins have been developed and put into practical use. For example, JP-A-50-98332, JP-A-59-71057, JP-A-59-184251, JP-A-5-21478, and the like, polycarbonate copolymers having various structures are binder resins. It is disclosed as. However, conventional organic photoreceptors have drawbacks such as surface wear and scratches caused by practical loads such as development with toner, friction with paper, and friction with a cleaning member (blade). Therefore, the current situation is that the printing performance is limited in practical use.

  On the other hand, Japanese Patent Laid-Open No. 56-135844 discloses a technique of an electrophotographic photoreceptor using a polyarylate (aromatic polyester) resin marketed under the trade name “U-polymer” as a binder. Among them, it is shown that the sensitivity is particularly excellent as compared with polycarbonate. Japanese Patent Application Laid-Open No. 3-6567 discloses an electrophotographic photosensitive member containing a polyarylate (aromatic polyester) copolymer having a structure using tetramethylbisphenol F and bisphenol A as a bisphenol component. ing. However, these aromatic polyesters have the drawbacks that the solubility of the photosensitive layer in the coating solvent and the stability of the solution are poor, and that when these are used as a binder for the photosensitive layer, the electrical properties deteriorate.

  In order to increase the mechanical strength, for example, an overcoat layer is provided (Japanese Patent Laid-Open No. 61-72256), and a binder polymer having a high wear resistance is used (Japanese Patent Laid-Open No. 63-148263, Japanese Patent Laid-Open No. Hei 3-). No. 221962) and the like have been proposed, but none of these effects are sufficient, or there are problems such as adverse effects on characteristics such as electrical characteristics.

  In recent years, a photoreceptor having better surface slip has been desired as the image quality is improved. In order to improve the slipperiness of the surface, a polysiloxane block copolymer is used as a binder (Japanese Patent Laid-Open Nos. 61-132955, 2-2406655, and 3-185451). Polycarbonate is used (JP-A-7-261440), fluorine atom-containing polycarbonate is used (JP-A-5-306335, JP-A-6-32884, JP-A-6-282944), polyester carbonate and polysiloxane Have been proposed (Japanese Patent Laid-Open No. 8-234468), polysiloxane-terminated polyester (Japanese Patent Laid-Open No. 2002-128883), etc. Or wear resistance is impaired, or electrical characteristics are adversely affected. At present, it contains a problem.

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 JP 61-72256 A JP-A-63-148263 Japanese Patent Laid-Open No. 3-221962 Japanese Patent Application Laid-Open No. 61-132594 JP-A-2-240655 Japanese Patent Laid-Open No. 3-185451 JP 7-261440 A JP-A-5-306335 JP-A-6-32884 Japanese Patent Laid-Open No. 6-282094 JP-A-8-234468 JP 2002-128883 A

  However, when the currently used polycarbonate resin is used in an electrophotographic process, it is still often insufficient in terms of wear resistance, scratch resistance, and the like. In addition, with the commercially available polyarylate resin “U-polymer”, although the wear resistance and sensitivity are slightly improved, the stability of the coating solution is poor, and the electrophotographic photosensitive member cannot be coated and manufactured. The surface slipperiness was poor.

  In addition, when a polyarylate (aromatic polyester) copolymer having a structure using tetramethylbisphenol F and bisphenol A is used as the bisphenol component disclosed in Japanese Patent Application Laid-Open No. 3-6567, it is conventional in terms of wear resistance. Although there is an improvement over polycarbonate, there is no superiority over polycarbonate in terms of slipperiness, and there is a problem that the performance is significantly inferior to polycarbonate in terms of electrical characteristics, particularly sensitivity and responsiveness.

  Therefore, the present situation is that an electrophotographic photoreceptor excellent in wear resistance and surface slipperiness while maintaining excellent electrical characteristics such as responsiveness is desired.

  Accordingly, as a result of intensive studies in view of these current situations, the present inventors have used a polyester resin having a polysiloxane structure at the end and having a specific repeating structure and a specific molecular weight in the photosensitive layer. When an electrophotographic photosensitive member is obtained, it has been found that the electrophotographic photosensitive member is excellent in wear resistance, surface slipperiness, and electrical characteristics in long-term repeated use while maintaining excellent electrical characteristics such as responsiveness.

That is, the first gist of the present invention is that an electrophotographic photosensitive member having at least a photosensitive layer on a conductive substrate contains a polyester resin satisfying the following conditions (A) to (C) in the photosensitive layer. An electrophotographic photosensitive member (claim 1).
(A) having a polysiloxane structure represented by the following general formula (1) on at least a part of the polymer terminal (B) having a repeating structure represented by the following general formula (2) (C) viscosity average molecular weight 42,000 to 80,000

(In the general formula (1), R ^{a to} R ^e each independently represents an alkyl group which may have a substituent, or an aromatic group which may have a substituent, and n is 1 to 500. Indicates an integer.)

(In General formula (2), R < ¹ > -R < ⁸ > is each independently the hydrogen atom, the alkyl group which may have a C1-C20 substituent, the alkoxyl group, and the aromatic which may be substituted. X ¹ represents any one of a group, X ¹ represents a single bond, an alkylene group, —CR ⁹ R ¹⁰ —, an oxygen atom, or a sulfur atom, R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a carbon number of 1; -20 alkyl group, an aromatic group which may have a substituent, or a group in which R ⁹ and R ¹⁰ are bonded to each other to form a ring which may have a substituent. )
The second gist of the present invention resides in an electrophotographic photosensitive member in which the general formula (2) is represented by the following general formula (3) (claim 2).

(In General Formula (3), R ^{1 to} R ⁸ are each independently a hydrogen atom, an alkyl group that may have a substituent having 1 to 20 carbon atoms, an alkoxyl group, or an optionally substituted aromatic group. R ⁹ and R ¹⁰ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aromatic group which may have a substituent, or R ⁹ and R ¹⁰ are Any one of the groups that are bonded to form an optionally substituted ring is shown.)
The third gist of the present invention resides in an electrophotographic photoreceptor in which the photosensitive layer further contains a compound represented by the following general formula (4).

(In General 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. Q represents a direct bond or a divalent residue, and R ^{11 to} R ¹⁸ may each independently have a hydrogen atom or a substituent. An alkyl group, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent, each of n ^{1 to} n ⁴ independently represents an integer of 0 to 4. Ar ^{1 to} Ar ⁶ may be bonded to each other to form a cyclic structure.)
Further, the fourth gist of the present invention is that the photosensitive layer has an oxy-oxygen having a clear peak at a Bragg angle 2θ ± 0.2 ° of 27.3 ° in powder X-ray diffraction using CuKα characteristic X-rays. The present invention resides in an electrophotographic photosensitive member containing titanium phthalocyanine (claim 4). According to a fifth aspect of the present invention, there is provided an image for forming an electrostatic latent image by performing image exposure on the electrophotographic photosensitive member, a charging unit for charging the electrophotographic photosensitive member, and the charged electrophotographic photosensitive member. An electrophotographic cartridge comprising: at least one of an exposure unit, a developing unit that develops the electrostatic latent image with toner, and a transfer unit that transfers the toner to a transfer target (claim). Item 5).

  According to a sixth aspect of the present invention, there is provided the electrophotographic photosensitive member, a charging unit for charging the electrophotographic photosensitive member, and an exposing unit for forming an electrostatic latent image by exposing the charged electrophotographic photosensitive member. A developing unit that develops the electrostatic latent image with toner, a transfer unit that transfers the toner to a transfer target, and a fixing unit that fixes the toner transferred to the transfer target. An image forming apparatus (claim 6).

  The electrophotographic photosensitive member of the present invention uses a polyester resin having a polysiloxane structure at the end and having a specific repeating structure and a specific molecular weight in the photosensitive layer, thereby providing good electrical characteristics and surface slipperiness. In addition, there is an effect that wear resistance is excellent in long-term repeated use.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. It is an X-ray diffraction diagram showing a powder X-ray diffraction spectrum of oxytitanium phthalocyanine used in Examples and Comparative Examples of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented without departing from the scope of the invention.
<< 1. Polyester resin >>
The electrophotographic photoreceptor of the present invention is characterized in that the photosensitive layer contains a polyester resin that satisfies the following conditions (A) to (C).
(A) having a polysiloxane structure represented by the following general formula (1) on at least a part of the polymer terminal (B) having a repeating structure represented by the following general formula (2) (C) viscosity average molecular weight 42,000 to 80,000

(In the general formula (1), R ^{a to} R ^e each independently represents an alkyl group which may have a substituent, or an aromatic group which may have a substituent, and n is 1 to 500. Indicates an integer.)

(In General formula (2), R < ¹ > -R < ⁸ > is each independently the hydrogen atom, the alkyl group which may have a C1-C20 substituent, the alkoxyl group, and the aromatic which may be substituted. X ¹ represents any one of a group, X ¹ represents a single bond, an alkylene group, —CR ⁹ R ¹⁰ —, an oxygen atom, or a sulfur atom, R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a carbon number of 1; -20 alkyl group, an aromatic group which may have a substituent, or a group in which R ⁹ and R ¹⁰ are bonded to each other to form a ring which may have a substituent. )
Hereinafter, for the sake of clarity, the polyester resin that satisfies the above conditions (A) to (C) may be referred to as a polyester resin α.

Hereinafter, the polyester resin α will be described in detail.
<1-1-1. Polysiloxane structure at the end of polyester resin polymer (Condition A)>
The polyester resin α contained in the electrophotographic photosensitive member of the present invention has a polysiloxane structure at least at a part of the polymer terminal. The polysiloxane structure is represented by the following general formula (1).

Although n in General formula (1) shows the integer of 1-500, Preferably it is 10-200, More preferably, it is 20-100. If n is too small, the slip improvement effect tends to decrease. On the other hand, if n is too large, the transparency of the resin or solution may be lost, and the electrical characteristics may be adversely affected.
R ^{a to} R ^e in the general formula (1) each independently represents an alkyl group which may have a substituent, or an aromatic group which may have a substituent.

The carbon number of R ^{a to} R ^e is not limited as long as the effects of the present invention are not significantly impaired. Specifically, it is usually 30 or less, preferably 6 or less, more preferably 3 or less, and particularly preferably carbon number. Is 1 (methyl group). If it exceeds this range, the slipperiness effect may be reduced.
Examples of the alkyl group which may have a substituent include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, an isobutyl group, or a straight chain having 5 to 30 carbon atoms, Examples include branched alkyl groups, cyclohexyl groups, chloromethyl groups, fluorine-substituted alkyl groups, and benzyl groups. Examples of the optionally substituted aromatic group include a phenyl group, a chlorophenyl group, a fluorophenyl group, and a naphthyl group. Of these, a methyl group, a fluoroalkyl group, and a phenyl group are preferable.

  Although the polysiloxane structure which the polyester resin (alpha) used for this invention has in at least one part of a polymer terminal is shown below, arbitrary things can be used unless the effect of this invention is impaired remarkably.

<1-1-2. Content of polysiloxane structure>
The polysiloxane represented by the general formula (1) with respect to the total amount of the polyester resin α having the polysiloxane structure represented by the general formula (1) at a part of the polymer terminal contained in the photosensitive layer of the present invention. The ratio (weight ratio) in which the structure is contained is an arbitrary amount as long as the effect of the present invention is not significantly impaired, but is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0. .1% by weight or more, particularly preferably 1% by weight or more, on the other hand, usually 25% by weight
Hereinafter, it is preferably 20% by mass or less, more preferably 15% by mass or less. When the content of the polysiloxane structure is in the above range, the slipping effect can be obtained satisfactorily. In addition, good mechanical properties, optical characteristics, electrical characteristics, adhesiveness, and the like can be obtained. Furthermore, compatibility with other resins is increased, and separation can be prevented.

<1-2. Main chain structure of polyester resin polymer (Condition B)>
The polyester resin α used in the present invention includes a repeating structure represented by the following general formula (2).

In the general formula (2), each of R ^{1 to} R ⁸ independently represents any one of a hydrogen atom, an alkyl group, an alkoxyl group, and an aromatic group that may have a substituent having 1 to 20 carbon atoms. X ¹ represents a single bond, an alkylene group, —CR ⁹ R ¹⁰ —, an oxygen atom, or a sulfur atom. R ₉ and R ₁₀ are each independently a hydrogen atom, an alkyl group which may have a substituent, an aromatic group which may have a substituent, or R ⁹ and R ¹⁰ bonded to each other. It represents one of the groups forming a ring which may have a substituent.

The alkyl group having 1 to 20 carbon atoms which may have a substituent in R ^{1 to} R ⁸ is an alkyl group having usually 20 or less carbon atoms, preferably 6 or less, and more preferably 3 or less. If it exceeds this range, there is a possibility that the wear resistance is lowered.
Specific examples of the alkyl group having 1 to 20 carbon atoms that may have this substituent include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, an isobutyl group, a cyclohexyl group, Examples include a chloromethyl group, a fluorinated alkyl group, and a benzyl group.

Specific examples of the alkoxy group which may have a substituent in R ^{1 to} R ⁸ include a methoxy group, an ethoxy group, a propoxy group, a cyclohexoxy group, and the like.
Specific examples of the aromatic group that may have a substituent in R ^{1 to} R ⁸ include a phenyl group, a chlorophenyl group, and a fluorophenyl group.
As a preferable combination in R ^{1 to} R ⁸ , R ² , R ⁴ , R ⁶ and R ⁸ are hydrogen atoms, and R ¹ , R ³ , R ⁵ and R ⁷ are hydrogen atoms or having 1 to 3 carbon atoms. It is an alkyl group. From the viewpoints of solubility and mechanical properties, R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁸ are particularly preferably hydrogen atoms, and R ¹ and R ⁷ are methyl groups.

Specific examples of the alkylene group for X ¹ include — (CH ₂ ) ₂ —, — (CH ₂ ) ₃ — and the like.
Specific examples of the alkyl group which may have a substituent in R ⁹ and R ¹⁰ include a methyl group, an ethyl group, a propyl group, a cyclohexyl group, and the like.
Specific examples of the aromatic group that may have a substituent in R ⁹ and R ¹⁰ include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a tolyl group, and the like.

In R ⁹ and R ^10, specific examples of the groups R ⁹ and R ¹⁰ form a ring which may have a bond to a substituent each other, cyclohexylidene group, and the like.
X ¹ is preferably —CR ⁹ R ¹⁰ —. Of these, the case where R ⁹ is a hydrogen atom and R ¹⁰ is a methyl group is particularly preferred.
Furthermore, the repeating unit represented by the above formula (2) preferably has a structure represented by the following formula (3).

In the above formula (3), R ¹ ~R ¹⁰ is the same as R ¹ to R ¹⁰ described above Formula (2). The polyester resin α contained in the photosensitive layer of the present invention can be produced from an aromatic diol and a dicarboxylic acid.
<1-2-1. Aromatic diol component>
Aromatic diols include 4,4′-biphenol, 3,3′-dimethyl-4,4′-dihydroxy-1,1′-biphenyl, 3,3′-di- (t-butyl) -4,4. '-Dihydroxy-1,1'-biphenyl, 3,3', 5,5'-tetramethyl-4,4'-dihydroxy-1,1'-biphenyl, 3,3 ', 5,5'-tetra- (T-butyl) -4,4′-dihydroxy-1,1′-biphenyl, 2,2 ′, 3,3 ′, 5,5′-hexamethyl-4,4′-dihydroxy-1,1′-biphenyl Biphenol components such as bis
(4-hydroxyphenyl) methane, bis- (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 1,1- Bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) butane, 2,2-bis- (4-hydroxyphenyl) Pentane, 2,2-bis- (4-hydroxyphenyl) -3-methylbutane, 2,2-bis- (4-hydroxyphenyl) hexane, 2,2-bis- (4-hydroxyphenyl) -4-methylpentane 1,1-bis- (4-hydroxyphenyl) cyclopentane, 1,1-bis- (4-hydroxyphenyl) cyclohexane, -(3-phenyl-4-hydroxyphenyl) methane, 1,1-bis- (3-phenyl-4-hydroxyphenyl) ethane, 1,1-bis- (3-phenyl-4-hydroxyphenyl) propane, 2 , 2-bis- (3-phenyl-4-hydroxyphenyl) propane, bis- (4-hydroxy-3-methylphenyl) methane, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane, 2 , 2-bis- (4-hydroxy-3-methylphenyl) propane, 2,2-bis- (4-hydroxy-3-ethylphenyl) propane, 2,2-bis- (4-hydroxy-3-isopropylphenyl) Propane, 2,2-bis- (4-hydroxy-3-sec-butylphenyl) propane, 1,1-bis- (4-hydroxy-3,5-dimethylphenol) Nyl) ethane, 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane, bis- (4-hydroxy-3,6-dimethylphenyl) methane, 1,1-bis- (4-hydroxy) -3,6-dimethylphenyl) ethane, bis- (4-hydroxyphenyl) phenylmethane, 1,1-bis- (4-hydroxyphenyl) -1-phenylethane, 1,1-bis- (4-hydroxyphenyl) ) -1-phenylpropane, bis- (4-hydroxyphenyl) diphenylmethane, bis- (4-hydroxyphenyl) dibenzylmethane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenylsulfone, 4,4 ′ -Dihydroxydiphenyl sulfide, phenolphthalein, 4,4 '-[1,4-phenylenebis (1- Chill vinylidene)] bisphenol, 4,4 '- [1,4-phenylene bis (1-methyl vinylidene)], and others bis [2-methylphenol].

  Among these, from the viewpoint of solubility and mechanical properties, bis- (4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 2,2-bis- (4-hydroxyphenyl) propane, 2 , 2-bis- (3-phenyl-4-hydroxyphenyl) propane, bis- (4-hydroxy-3-methylphenyl) methane, 1,1-bis- (4-hydroxyphenyl) cyclohexane, 1,1-bis -(4-hydroxy-3-methylphenyl) ethane, 2,2-bis- (4-hydroxy-3-methylphenyl) propane, bis- (4-hydroxy-3,5-dimethylphenyl) methane, 1,1 -Bis- (4-hydroxy-3,5-dimethylphenyl) ethane, 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane, bi - (4-hydroxy-3,6-dimethylphenyl) methane, 1,1-bis - (4-hydroxyphenyl) -1-phenylethane and the like.

<1-2-2. Dicarboxylic acid component>
Examples of the dicarboxylic acid component include diphenyl ether-2,2′-dicarboxylic acid, diphenyl ether-2,4′-dicarboxylic acid, and diphenyl ether-4,4′-dicarboxylic acid. In consideration, diphenyl ether-4,4′-dicarboxylic acid is preferred. These components may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations. It is also possible to use isophthalic acid and terephthalic acid components in combination.

<1-3. Copolymerization component>
The polyester resin α contained in the photosensitive layer of the present invention may be a copolymer having another repeating unit (copolymerization component). The copolymerization type may be a block, graft, or multiblock copolymer. Examples of the copolymer component to be copolymerized here include various resins such as polycarbonate, polyarylate, polysulfone, polyether, polyketone, polyamide, polysiloxane, polyimide, polystyrene, and polyolefin. Particularly preferred is polycarbonate resin. One of these resins may be selected alone to form a copolymer with the polyester resin of the present invention, or two or more may be selected in any combination and ratio to be used in the present invention. A copolymer may be formed with α.

In the case where the polyester resin α contained in the present invention is a copolymer and is used as a binder resin in the photosensitive layer of the electrophotographic photosensitive member of the present invention described later, the amount of the copolymer component is usually in the total polyester resin. It is 70 mol% or less, preferably 50 mol% or less, particularly preferably 30 mol% or less. If this is too large, the mechanical properties may be reduced.
<1-4. Viscosity average molecular weight of polyester resin (Condition C)>
The lower limit of the viscosity average molecular weight of the polyester resin α contained in the photosensitive layer of the present invention is 42,000 or more, more preferably 50,000 or more, and particularly preferably 60,000 or more from the viewpoint of printing durability. On the other hand, the upper limit is 80,000 or less. If the viscosity average molecular weight is too small, the wear resistance may be deteriorated. On the other hand, if the viscosity average molecular weight is too large, the viscosity of the coating solution will be high, and a larger amount of solvent may be required than usual when coating, which may reduce productivity. is there.

<1-5. Production method of polyester resin>
The production method of the polyester resin α contained in the photosensitive layer of the present invention is not limited as long as the effects of the present invention are not significantly impaired. For example, the aromatic diol component and the dicarboxylic acid component are polymerized by a known polymerization method. Can be mentioned. Known polymerization methods include interfacial polymerization, melt polymerization, and solution polymerization.

For example, in the case of production by an interfacial polymerization method, a solution in which one or more biphenyl components or bisphenol components are dissolved in an alkaline aqueous solution and a halogenated hydrocarbon solution in which one or more aromatic dicarboxylic acid chloride components are dissolved. Mix. At this time, a quaternary ammonium salt or a quaternary phosphonium salt may be present as a catalyst.
The polymerization temperature is usually in the range of 0 to 40 ° C., and the polymerization time is preferably in the range of 2 to 12 hours from the viewpoint of productivity. After completion of the polymerization, the water phase and the organic phase are separated, and the polymer dissolved in the organic phase is washed and recovered by a known method to obtain the intended resin.

  Examples of the alkali component used in the interfacial polymerization method include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. One of these may be used alone, or two or more may be used in any combination and ratio. The amount of alkali used is preferably in the range of 1.0 to 3 times the phenolic hydroxyl group contained in the reaction system.

Examples of the halogenated hydrocarbon used in the above-described interfacial polymerization method include dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, dichlorobenzene, and the like.
Examples of the quaternary ammonium salt or quaternary phosphonium salt used as a catalyst in the above-mentioned interfacial polymerization method include salts of tertiary alkylamines such as tributylamine and trioctylamine such as hydrochloric acid, bromic acid and iodic acid, and benzyltriethylammonium chloride. , Benzyltrimethylammonium chloride, benzyltributylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, trioctylmethylammonium chloride, tetrabutylphosphonium bromide, triethyloctadecylphosphonium bromide, N-laurylpyridinium chloride, laurylpicolinium Examples include chloride. One of these may be used alone, or two or more may be used in any combination and ratio.

Specific examples of the biphenyl component or the bisphenol component include the above-mentioned aromatic diols, but one or more of these may be used in combination.
As a method for producing a polyester resin α containing a polysiloxane structure at the polymer terminal contained in the photosensitive layer of the present invention, for example, monofunctional phenol structures represented by the following structural formulas (1-1) to (1-10) are used. A method in which the polysiloxane or alkali salt thereof is allowed to coexist during polymerization can be applied.

The preparation method of the polysiloxane component containing the monofunctional phenol is arbitrary. For example, the polysiloxane component containing the monofunctional phenol is dissolved in an organic solvent such as methylene chloride, or an alkali such as Na or K. A method of charging by dissolving or suspending in an aqueous solution can be mentioned.
The polysiloxane containing monofunctional phenol may be charged before the polymerization reaction, during the polymerization reaction, or at the end of the polymerization reaction.

  The monofunctional phenol compound may be a polysiloxane bonded alone in the polymerization system, or other monofunctional phenol compounds such as p-tert-butylphenol, phenol, cumylphenol, octylphenol, 2 , 6-dimethylphenol, 2,4,6-trimethylphenol, 2,3,5-trimethylphenol, phenol and the like. When using together, you may use 2 or more types by arbitrary combinations and a ratio.

In addition, as another manufacturing method of polyester which has the polysiloxane represented by the above-mentioned general formula (1) in at least a part of the terminal, one terminal Si-H structure to polyester having a carbon-carbon double bond at the terminal And a method of producing the polysiloxane by hydrosilylation reaction.
A molecular weight modifier may be used in the polymerization of the polyester resin. Examples of the molecular weight regulator include phenol, o, m, p-cresol, o, m, p-ethylphenol, o, m, p-propylphenol, o, m, p-tert-butylphenol, pentylphenol, hexyl. Alkylphenols such as phenol, octylphenol, nonylphenol, 2,6-dimethylphenol, 2,4,6-trimethylphenol, 2,3,5-trimethylphenol; monofunctional such as o, m, p-phenylphenol Phenol; monofunctional acid halides such as acetic acid chloride, butyric acid chloride, octylic acid chloride, benzoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, benzenephosphonyl chloride and their substitutes can be used . One of these may be used alone, or two or more may be used in any combination and ratio.

As the purification method after polymerization of the polyester resin, any method can be used as long as the effects of the present invention are not significantly impaired. For example, the polyester resin solution is an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide; hydrochloric acid, An aqueous solution of acid such as nitric acid and phosphoric acid; a method of separating by standing separation, centrifugation, etc. after washing with water or the like.
Other purification methods include, for example, a method in which the produced polyester resin solution is precipitated in a solvent in which the polyester resin is insoluble, a method in which the polyester resin solution is dispersed in warm water, and the solvent is distilled off, or the polyester resin You may refine | purify by the method etc. which distribute | circulate a solution to an adsorption column etc.

  The polyester resin after purification is deposited in water, alcohol or other organic solvent in which the polyester resin is insoluble, or the solvent of the polyester resin is distilled off in warm water or in a dispersion medium in which the polyester resin is insoluble, or heating and decompression For example, the solvent may be removed by distilling off the solvent, and when the slurry is taken out, the solid can be taken out by a centrifuge or a filter.

The obtained polyester resin is usually dried at a temperature equal to or lower than the decomposition temperature of the polyester resin, but can be preferably dried at a temperature not lower than 20 ° C. and not higher than the melting temperature of the resin. At this time, it is preferable to dry under reduced pressure.
Preferably, the drying time is longer than the time until the purity of impurities such as the residual solvent becomes below a certain level. Specifically, the residual solvent is usually 1000 ppm or lower, preferably 300 ppm or lower, more preferably 100 ppm or lower. dry.

<2. Electrophotographic photoreceptor>
The electrophotographic photosensitive member of the present invention has at least a photosensitive layer on a conductive support, and as a binder resin in the photosensitive layer, at least a part of the polymer terminal is represented by the above general formula (1). Excellent electrophotographic characteristics when it has a siloxane structure and a repeating structure represented by the general formula (2) (conditions A and B above) and contains a polyester resin having a predetermined viscosity average molecular weight (condition C). Is expressed.

<2-1. Conductive support>
There is no particular limitation on the conductive support, but for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper, and nickel, and conductive powder such as metal, carbon, and tin oxide are added to impart conductivity. A resin material, a resin, glass, paper, or the like on which a conductive material such as aluminum, nickel, or ITO (indium tin oxide) is deposited or applied on the surface is mainly used. These may be used alone or in combination of two or more in any combination and ratio. As a form of the conductive support, a drum form, a sheet form, a belt form or the like is used. Further, a conductive material having an appropriate resistance value may be used on a conductive support made of a metal material in order to control conductivity and surface properties and to cover defects.

Moreover, when using metal materials, such as an aluminum alloy, as an electroconductive support body, you may use, after giving an anodic oxide film. When an anodized film is applied, it is desirable to perform a sealing treatment by a known method.
The surface of the support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. In order to reduce the cost, it is possible to use the drawing tube as it is without performing the cutting process.

<2-2. Undercoat layer>
An undercoat layer may be provided between the conductive support and the photosensitive layer described later for improving adhesion and blocking properties. As the undercoat layer, a resin or a resin in which particles such as a metal oxide are dispersed is used. The undercoat layer may be a single layer or a plurality of layers.

  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. One kind of these particles may be used alone, or a plurality of kinds 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 silicon. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Moreover, the thing of a several crystal state may be contained.

In addition, various particle sizes of metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle size is preferably 10 nm or more and 100 nm or less, and particularly 10 nm or more and 50 nm or less. preferable. This average primary particle size can be obtained from a TEM photograph or the like.
The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. The binder resin used for the undercoat layer is epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, chloride resin. Cellulose esters such as vinylidene resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacrylic resin, polyacrylamide resin, polyvinylpyrrolidone resin, polyvinylpyridine resin, water-soluble polyester resin, nitrocellulose Resin, cellulose ether resin, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compound, zirconium The organic zirconium compound alkoxide compounds, titanyl chelate compounds, organic titanyl compounds such as titanium alkoxide compounds include known binder resins such as a silane coupling agent. These may be used alone or in combination of two or more in any combination and ratio. Moreover, you may use with the hardening | curing form with the hardening | curing agent. Among these, alcohol-soluble copolymerized polyamides, modified polyamides, and the like are preferable because they exhibit good dispersibility and coatability.

The use ratio of the inorganic particles to the binder resin used in the undercoat layer can be arbitrarily selected. From the viewpoint of the stability of the dispersion and the coating property, the binder resin is usually 10% by mass or more, It is preferable to use in the range of 500 mass% or less.
The thickness of the undercoat layer is arbitrary as long as the effects of the present invention are not significantly impaired, but the viewpoint of improving the electrical characteristics, strong exposure characteristics, image characteristics, repeat characteristics, and coating properties during production of the electrophotographic photosensitive member. Therefore, it is usually 0.01 μm or more, preferably 0.1 μm or more, and usually 30 μm or less, preferably 20 μm or less. A known antioxidant or the like may be mixed in the undercoat layer. For the purpose of preventing image defects, pigment particles, resin particles and the like may be included.

<2-3. Photosensitive layer>
As a type of the photosensitive layer, a charge generation material and a charge transport material are present in the same layer and are dispersed in a binder resin, a charge generation layer in which a charge generation material is dispersed in a binder resin, and a charge. A functional separation type (laminated type) composed of two layers of a charge transport layer in which a transport material is dispersed in a binder resin can be mentioned, but any type may be used.

In addition, as the laminated photosensitive layer, a charge generation layer and a charge transport layer are laminated in this order from the conductive support side, and a charge transport layer and a charge generation layer are laminated in this order. There are reverse laminated type photosensitive layers, and any of them can be adopted, but a forward laminated type photosensitive layer capable of exhibiting the most balanced photoconductivity is preferable.
<2-3-1. Multilayer photosensitive layer>
<2-3-1-1. Charge generation layer>
In the case of a laminated type photoreceptor (function separation type photoreceptor), the charge generation layer is formed by binding a charge generation material with a binder resin.

  Examples of the charge generation material include inorganic photoconductive materials such as selenium and its alloys, cadmium sulfide, and organic photoconductive materials such as organic pigments, but organic photoconductive materials are preferred, especially organic pigments. Is preferred. Examples of organic pigments include phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene (squarylium) pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments. . Among these, phthalocyanine pigments or azo pigments are particularly preferable. When organic pigments are used as the charge generating substance, usually, fine particles of these organic pigments are used in the form of a dispersion layer bound with various binder resins.

  When a metal-free phthalocyanine compound or a metal-containing phthalocyanine compound is used as the charge generation material, a photosensitive member having a high sensitivity to a laser beam having a relatively long wavelength, for example, a laser beam having a wavelength around 780 nm, is obtained. When an azo pigment such as diazo or trisazo is used, it is sufficient for white light, laser light having a wavelength around 660 nm, or laser light having a relatively short wavelength, for example, laser having a wavelength around 450 nm or 400 nm. A photosensitive member having a high sensitivity can be obtained.

When an organic pigment is used as the charge generating material, a phthalocyanine pigment or an azo pigment is particularly preferable. The phthalocyanine pigment provides a photosensitive material with high sensitivity to a laser beam having a relatively long wavelength, and the azo pigment has a sufficient sensitivity to white light and a laser beam having a relatively short wavelength. , Each is excellent.
When using a phthalocyanine pigment as a charge generation material, specifically, metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum or other metal or oxide thereof, halide, water Those having crystal forms of coordinated phthalocyanines such as oxides and alkoxides, and phthalocyanine dimers using oxygen atoms as bridging atoms are used. Particularly, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), and D-type (also known as Y-type), which are highly sensitive crystalline Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, hydroxyindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and type I, type II, etc. The [mu] -oxo-aluminum phthalocyanine dimer is preferred.

  Among these phthalocyanines, A-type (also known as β-type), B-type (also known as α-type), and powder X-ray diffraction angle 2θ (± 0.2 °) are 27.1 ° or 27.3 °. D-type (Y-type) titanyl phthalocyanine, II-type chlorogallium phthalocyanine, V-type and 28.1 ° have the strongest peaks, and 26.2 ° have peaks Hydroxygallium phthalocyanine having a clear peak at 28.1 ° and a full width at half maximum W of 25.9 ° of 0.1 ° ≦ W ≦ 0.4 °, G-type μ-oxo -Gallium phthalocyanine dimer and the like are particularly preferable. Among these, D-type (Y-type) titanyl phthalocyanine is most preferable because it shows good sensitivity.

  The phthalocyanine compound may be a single compound or several mixed or mixed crystal states. As the mixed state that can be put in the phthalocyanine compound or crystal state here, those obtained by mixing the respective constituent elements later may be used, or they may be mixed in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, and crystallization. It may be the one that caused the condition. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known. In order to generate a mixed crystal state, as described in JP-A-10-48859, two types of crystals are mixed, mechanically ground and made amorphous, and then converted into a specific crystal state by solvent treatment. The method of doing is mentioned.

When an azo pigment is used as the charge generation material, various bisazo pigments and trisazo pigments are preferably used.
When an organic pigment is used as the charge generation material, one kind may be used alone, or two or more kinds of pigments may be mixed and used. In this case, it is preferable to use a combination of two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions of the visible region and the near red region. Among them, a disazo pigment, a trisazo pigment and a phthalocyanine pigment are preferably used in combination. More preferred.

The binder resin used for the charge generation layer is not particularly limited, but examples include polyvinyl butyral resin, polyvinyl formal resin, polyvinyl acetal type such as partially acetalized polyvinyl butyral resin in which a part of butyral is modified with formal, acetal, or the like. Resin, Polyarylate resin, Polycarbonate resin, Polyester resin, Modified ether type polyester resin, Phenoxy resin, Polyvinyl chloride resin, Polyvinylidene chloride resin, Polyvinyl acetate resin, Polystyrene resin, Acrylic resin, Methacrylic resin, Polyacrylamide resin, Polyamide Resin, polyvinyl pyridine resin, cellulosic resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, vinyl chloride -Vinyl acetate-vinyl acetate copolymers such as vinyl acetate copolymers, hydroxy-modified vinyl chloride-vinyl acetate copolymers, carboxyl-modified vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, etc. Insulating resins such as polymers, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, styrene-alkyd resins, silicon-alkyd resins, phenol-formaldehyde resins, poly-N-vinylcarbazole, polyvinyl anthracene, polyvinyl And organic photoconductive polymers such as perylene. Any one of these binder resins may be used alone, or two or more thereof may be mixed and used in any combination.

Specifically, the charge generation layer is prepared by dispersing the halogen-substituted indium phthalocyanine of the present invention and other charge generation materials used in some cases in a solution obtained by dissolving the above-described binder resin in an organic solvent. Is applied on a conductive support (or an undercoat layer when an undercoat layer is provided).
The solvent used for preparing the coating solution is not particularly limited as long as it dissolves the binder resin. For example, saturated aliphatic solvents such as pentane, hexane, octane, and nonane, and aromatics such as toluene, xylene, and anisole. Group solvents, halogenated aromatic solvents such as chlorobenzene, dichlorobenzene, chloronaphthalene, amide solvents such as dimethylformamide, N-methyl-2-pyrrolidone, methanol, ethanol, isopropanol, n-butanol, benzyl alcohol, etc. Alcohol solvents, aliphatic polyhydric alcohols such as glycerin and polyethylene glycol, chain or cyclic ketone solvents such as acetone, cyclohexanone, methyl ethyl ketone, ester solvents such as methyl formate, ethyl acetate, n-butyl acetate, methylene chloride ,Black Halogenated hydrocarbon solvents such as form, 1,2-dichloroethane, chain or cyclic ether solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve, acetonitrile, dimethyl Aprotic polar solvents such as sulfoxide, sulfolane, hexamethylphosphoric triamide, n-butylamine, isopropanolamine, diethylamine, triethanolamine, nitrogen-containing compounds such as ethylenediamine, triethylenediamine, triethylamine, mineral oil such as ligroin, water, etc. Can be mentioned. Any one of these may be used alone, or two or more of these may be used in combination. In addition, when providing the above-mentioned undercoat layer, what does not melt | dissolve this undercoat layer is preferable.

  In the charge generation layer, the mixing ratio (weight) of the binder resin and the charge generation material is usually 10 parts by mass or more, preferably 30 parts by mass or more, and usually 1000 parts by mass with respect to 100 parts by mass of the binder resin. Part or less, preferably 500 parts by mass or less, and the film thickness is usually 0.1 μm or more, preferably 0.15 μm or more, and usually 10 μm or less, preferably 0.6 μm or less. If the ratio of the charge generation material is too high, the stability of the coating solution may be reduced due to aggregation of the charge generation material, while if the ratio of the charge generation material is too low, the sensitivity as a photoreceptor may be decreased. There is.

As a method for dispersing the charge generation material, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, or a sand mill dispersion method can be used. At this time, it is effective to refine the particles to a particle size in the range of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.
<2-3-1-2. Charge transport layer>
The charge transport layer of the multilayer photoreceptor contains a charge transport material and usually contains a binder resin and other components used as necessary. Specifically, such a charge transport layer is prepared by, for example, preparing a coating solution by dissolving or dispersing a charge transport material and a binder resin in a solvent. In addition, in the case of a reverse lamination type photosensitive layer, it can be obtained by coating and drying on a conductive support (or on the undercoat layer when an undercoat layer is provided).

(Charge transport material)
The charge transport material is not particularly limited, and any material can be used. Examples of charge transport materials include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron withdrawing materials such as quinone compounds such as diphenoquinone, carbazole derivatives, indoles Derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, heterocyclic compounds such as benzofuran derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives and multiple types of these compounds bind Or an electron donating substance such as a polymer having a group consisting of these compounds in the main chain or side chain. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable.

  Among charge transport materials, a compound having a structure represented by the following general formula (4) is preferably used.

In General Formula (4), Ar ^{1 to} Ar ⁶ each independently represent 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 in the case of m ¹ = 0 and Ar ^{6 in} the case of m ² = 0 each represent an alkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. It is a monovalent heterocyclic group which may have. Ar ⁵ in the case of m ¹ = 1 and Ar ^{6 in} the case of m ² = 1 each represent an alkylene group that may have a substituent, an arylene group that may have a substituent, or a substituent. It represents a divalent heterocyclic group which may have. Q represents a direct bond or a divalent residue. R ^{11 to} R ¹⁸ are each independently a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic ring which may have a substituent. Represents a group. n ¹ ~n ⁴ represents each independently integers from 0-4. Ar ^{1 to} Ar ⁶ may be bonded to each other to form a cyclic structure.

Furthermore, in the general formula (4), R ^{11 to} R ¹⁸ each independently represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. The aralkyl group which may have and the heterocyclic group which may have a substituent are represented.
In the general formula (4), when R ^{11 to} R ¹⁸ are alkyl groups, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, pentyl group, hexyl group, heptyl group, cyclopentyl group, cyclohexyl group Among these, an alkyl group having 1 to 6 carbon atoms is preferable. 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.

When R ^{11 to} R ¹⁸ are an aryl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group,
A pyrenyl group etc. are mentioned, A C6-C12 aryl group is preferable. When R ^{11 to} R ¹⁸ are a heterocyclic group, an aromatic heterocyclic ring is preferable, and examples thereof include a furyl group, a thienyl group, and a pyridyl group, and a monocyclic aromatic heterocyclic ring is more preferable.
Among R ^{11 to} R ¹⁸ , the most preferable are a methyl group and a phenyl group.

In General 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 in the case of m ¹ = 0 and Ar ^{6 in} the case of m ² = 0 each represent an alkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a monovalent heterocyclic group which may have, Ar ⁵ in the case of m ¹ = 1 and Ar ⁶ in the case of m ² = 1 are each an alkylene group which may have a substituent, Represents an arylene group which may have a group, or a divalent heterocyclic group which may have a substituent. Specifically, 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 14 carbon atoms is preferable; the arylene group includes a phenylene group and a naphthylene group. A phenylene group is preferable.

In the general formula (4), the monovalent heterocyclic group is preferably an aromatic heterocyclic ring, and examples thereof include a furyl group, a thienyl group, and a pyridyl group, and a monocyclic aromatic heterocyclic ring is more preferable. . As the divalent heterocyclic group, an aromatic heterocyclic ring is preferable, and examples thereof include a pyridylene group and a thienylene group, and a monocyclic aromatic heterocyclic ring is more preferable. Of these, the most preferred are Ar ¹ and Ar ² are phenylene groups, and Ar ³ is a phenyl group.

In general formula (4), among groups represented by R ^{11 to} R ¹⁸ and Ar ^{1 to} Ar ⁶ , an alkyl group,
The aryl group, aralkyl group, and heterocyclic group may further have a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom; methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, and tert-butyl. Group, pentyl group, hexyl group, cyclopentyl group, cyclohexyl group and other alkyl groups; methoxy group, ethoxy group, propyloxy group and other alkoxy groups; methylthio group, ethylthio group and other alkylthio groups; vinyl group, allyl group and other alkenyl groups Groups; aralkyl groups such as benzyl, naphthylmethyl, and phenethyl groups; aryloxy groups such as phenoxy and triloxy groups; arylalkoxy groups such as benzyloxy and phenethyloxy groups; aryl groups such as phenyl and naphthyl groups; Aryl vinyl groups such as styryl groups and naphthyl vinyl groups; Acyl groups such as til group and benzoyl group; Dialkylamino groups such as dimethylamino group and diethylamino group; Diarylamino groups such as diphenylamino group and dinaphthylamino group; Diaralkylamino groups such as dibenzylamino group and diphenethylamino group A diheterocyclic amino group such as a group, a dipyridylamino group or a dithienylamino group; a substituted amino group such as a diallylamino group or a disubstituted amino group obtained by combining substituents of the amino group described above; and a cyano group, a nitro group, A hydroxyl group etc. are mentioned. 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 include a halogen atom, a cyano group, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, and 6 to 12 carbon atoms. An arylthio group having 6 to 12 carbon atoms, and a dialkylamino group having 2 to 8 carbon atoms, more preferably a halogen atom, an alkyl group having 1 to 6 carbon atoms, and a phenyl group, and a methyl group and a phenyl group. Is 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, and 0 is preferable.
In general formula (4), Q represents a direct bond or a divalent residue, and 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 is an oxygen atom, S is a sulfur atom, and Z may have an arylene group or 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, and a carbon number. Examples thereof include an alkenyl group having 1 to 6 carbon atoms and an aryl group having 6 to 14 carbon atoms.
Any one of these charge transport materials may be used alone, or two or more thereof may be used in any 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.

[Binder resin]
The binder resin for the charge transport layer used in the electrophotographic photosensitive member of the present invention is <1. Polyester resin α described in detail in Polyester Resin>. The binder resin may be a mixture of the polyester resin α and other resins used in the present invention. Examples of other resins include butadiene resins, styrene resins, vinyl acetate resins, vinyl chloride resins, acrylic ester resins, Polymers and copolymers of vinyl compounds such as methacrylic ester resin, vinyl alcohol resin, ethyl vinyl ether, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal, polycarbonate resin, polyester resin, polyarylate resin, polyamide resin, polyurethane Resins, cellulose ester resins, phenoxy resins, silicon resins, silicon-alkyd resins, poly-N-vinylcarbazole resins, and the like can be given. These binder resins can also be used after being crosslinked by heat, light or the like using an appropriate curing agent.

  The resin used in combination is preferably a polycarbonate resin or a polyarylate resin from the viewpoint of electrical characteristics, and more preferably a polyarylate resin having a structure represented by the following general formula (5) having no polysiloxane structure at the terminal. .

(In the general formula (5), Ar ^{7 to} Ar ¹⁰ each independently represent an arylene group which may have a substituent, and X ² represents a single bond, an oxygen atom, a sulfur atom, and the following general formula (6). Or a group represented by the following general formula (7), wherein k represents an integer of 0 or more, and Y represents a single bond, an oxygen atom, a sulfur atom, or the following general formula (8). Group represented.)

(In the formula, R ¹⁹ and R ²⁰ each independently represents a hydrogen atom, an alkyl group, or an aryl group, and R ¹⁹ and R ²⁰ may combine to form a ring.)

(R ²¹ in the formula is an alkylene group, an arylene group, or a group represented by the following general formula (8).)

(In the formula, R ²² and R ²³ each independently represents an alkylene group, and Ar ¹¹ represents an arylene group.)

(In the formula, R ²⁴ and R ²⁵ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group, and R ²⁴ and R ²⁵ may combine to form a ring.)
<Structure>
In the general formula (5), Ar ^{7 to} Ar ¹⁰ each independently represent an arylene group which may have a substituent. As carbon number which an arylene group has, it is 6 or more normally, and the upper limit is 20 or less normally, Preferably it is 10 or less, More preferably, it is 6. If the number of carbon atoms is too large, the production cost increases and the electrical characteristics may also deteriorate.

Specific examples of Ar ^{7 to} Ar ¹⁰ include 1,2-phenylene group, 1,3-phenylene group, 1
, 4-phenylene group, naphthylene group, anthrylene group, phenanthrylene group and the like. Among these, the arylene group is preferably a 1,4-phenylene group from the viewpoint of electrical characteristics. An arylene group may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations.

Specific examples of the substituent for Ar ^{7 to} Ar ¹⁰ include an alkyl group, an aryl group, a halogen group, and an alkoxy group. Among them, considering the mechanical properties as a binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the alkyl group is preferably a methyl group, an ethyl group, a propyl group, or an isopropyl group, and is preferably an aryl group. Is preferably a phenyl group or a naphthyl group, a halogen group is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and an alkoxy group is preferably a methoxy group, an ethoxy group, a propoxy group or a butoxy group.

In addition, when a substituent is an alkyl group, carbon number of the alkyl group is usually 1 or more, and usually 10 or less, preferably 8 or less, more preferably 2 or less.
More specifically, Ar ⁹ and Ar ¹⁰ each independently preferably has a substituent number of 0 or more and 2 or less, more preferably has a substituent from the viewpoint of adhesion, and in particular, substitution from the viewpoint of wear resistance. It is particularly preferable that the number of groups is one. Moreover, as a substituent, an alkyl group is preferable and a methyl group is particularly preferable.

From the above viewpoint, it is preferable that at least one of Ar ⁹ and Ar ¹⁰ is an arylene group having a substituent.
On the other hand, Ar ⁷ and Ar ⁸ each independently preferably have 0 or more and 2 or less substituents, and more preferably have no substituents from the viewpoint of wear resistance.
In the general formula (5), X ² is a single bond, an oxygen atom, a sulfur atom, a group represented by the following general formula (6), or a group represented by the following general formula (7). R ¹⁹ and R ^{20 in} (6) each independently represent a hydrogen atom, an alkyl group, or an aryl group, and R ¹⁹ and R ²⁰ are bonded to form a ring such as a cycloalkylidene group. General formula (7)
R ²¹ therein is an alkylene group, an arylene group, or a group represented by the following general formula (8), and R ²² and R ²³ in the general formula (8) each independently represents an alkylene group. , Ar ¹¹ represents an arylene group.

In general formula (5), as preferred X ² , an oxygen atom, a sulfur atom, a structure represented by general formula (6), or a divalent organic residue having a structure represented by general formula (7) Can be mentioned.
Examples of the alkyl group represented by R ¹⁹ and R ^{20 in} the general formula (6) include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the aryl group include a phenyl group and a naphthyl group. In addition, examples of the cycloalkylidene group formed by combining R ¹⁹ and R ²⁰ in the general formula (6) include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. Furthermore, examples of the alkylene group for R ^{21 in} the general formula (7) include a methylene group, an ethylene group, and a propylene group. Examples of the arylene group represented by R ^{21 in} the general formula (7) include a phenylene group and a terphenylene group. Specific examples of the group represented by the general formula (8) include a group represented by the following general formula (10).

Among these, X ² is preferably an oxygen atom.
In the general formula (5), Y is a single bond, an oxygen atom, a sulfur atom, or a group represented by the following general formula (9).

R ²⁴ and R ²⁵ in the general formula (9) each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a cycloalkylidene group formed by combining R ²⁴ and R ²⁵ . Considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, R ²⁴ and R ²⁵ in the general formula (9) are preferably phenyl groups or naphthyl groups as aryl groups. The alkoxy group is preferably a methoxy group, an ethoxy group, or a butoxy group. Moreover, as an alkyl group, a C1-C10 alkyl group is preferable, More preferably, it is C1-C8, Most preferably, it is C1-2. Considering the simplicity of production of the divalent hydroxyaryl component used in producing the polyarylate resin, Y is a single bond, —O—, —S—, —CH ₂ —, —CH (CH ₃ ) —. , —C (CH ₃ ) ₂ — and cyclohexylene are preferable, and —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — and cyclohexylene are particularly preferable. CH ₂ — and —CH (CH ₃ ) —.

The polyarylate resin (5) is preferably a polyarylate resin containing a repeating structure represented by the following general formula (11). In general formula (11) below, Ar ^{12 to} Ar
¹⁵ represents an arylene group which may each independently have a substituent, and R ²⁶ represents a hydrogen atom or an alkyl group.

In the general formula (11), Ar ^{12 to} Ar ¹⁵ each correspond to the Ar ^{7 to} Ar ¹⁰ , and particularly preferably a phenylene group which may have a substituent. Moreover, as a preferable substituent, it is a hydrogen atom or an alkyl group, Most preferably, it is a methyl group. Furthermore, in the general formula (11), Ar ¹⁴ and Ar ¹⁵ are phenylene groups having a methyl group, and Ar ¹² and Ar ¹³ are particularly preferably phenylene groups having no substituent. R ²⁶ represents a hydrogen atom or an alkyl group. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably a methyl group.

<Divalent hydroxyaryl residue>
The divalent hydroxyaryl component to be a divalent hydroxyaryl residue in the polyarylate resin is represented by the following general formula (12), but is preferably represented by the following general formula (13).

Ar ⁹ , Ar ¹⁰ and Y in the general formula (12) are as described above.

Ar ¹⁴ , Ar ¹⁵ and R ²⁶ in the general formula (13) are as described above.
Specifically, when R ²⁶ in the general formula (13) is a hydrogen atom, bis (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (3-hydroxyphenyl) methane, (2-hydroxyphenyl) ( 4-hydroxyphenyl) methane, bis (3-hydroxyphenyl) methane, (3-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) methane, bis (2-hydroxy-3-methylphenyl) Methane, bis (2-hydroxy-3-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (3- Hydroxy-4-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (4-hydroxy) -3-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, bis (3-hydroxy-4-methylphenyl) methane, bis (3-hydroxy-4) -Ethylphenyl) methane, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) methane, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, Examples include bis (4-hydroxy-3-methylphenyl) methane and bis (4-hydroxy-3-ethylphenyl) methane.

When R ²⁶ is a methyl group, 1,1-bis (2-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (3-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) ) -1- (4-hydroxyphenyl) ethane, 1,1-bis (3-hydroxyphenyl) ethane, 1- (3-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane, 1,1-bis ( 4-hydroxyphenyl) ethane, 1,1-bis (2-hydroxy-3-methylphenyl) ethane, 1,1-bis (2-hydroxy-3-ethylphenyl) ethane, 1- (2-hydroxy-3-) Methylphenyl) -1- (3-hydroxy-4-methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (3-hydroxy-4-ethylphenyl) Nyl) ethane, 1- (2-hydroxy-3-methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (4-hydroxy) -3-ethylphenyl) ethane, 1,1-bis (3-hydroxy-4-methylphenyl) ethane, 1,1-bis (3-hydroxy-4-ethylphenyl) ethane, 1- (3-hydroxy-4) -Methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (3-hydroxy-4-ethylphenyl) -1- (4-hydroxy-3-ethylphenyl) ethane, 1,1- Bis (4-hydroxy-3-methylphenyl) ethane and 1,1-bis (4-hydroxy-3-ethylphenyl) ethane are mentioned.

Among these, when R ²⁶ in the general formula (13) is a hydrogen atom, bis (4-hydroxyphenyl) methane, (2-hydroxyphenyl) is considered in consideration of the simplicity of production of the divalent hydroxyaryl component. (4-Hydroxyphenyl) methane, bis (2-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, and bis (4-hydroxy-3-ethylphenyl) methane are particularly preferred. It is also possible to use a combination of a plurality of hydroxyaryl components.

When R ²⁶ in the general formula (13) is a methyl group, 1,1-bis (4-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane 1,1-bis (2-hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, and 1,1-bis (4-hydroxy-3-ethylphenyl) ethane are particularly preferable. A combination of a plurality of these divalent hydroxyaryl components can also be used.

Although general formula (13) is contained in general formula (12), the compound of general formula (12) other than the illustration of the said general formula (13) is also demonstrated below.
Specific examples of the divalent hydroxyaryl component represented by the general formula (12) include 3, 3 ′,
5,5′-tetramethyl-4,4′-dihydroxybiphenyl, 2,4,3 ′, 5′-tetramethyl-3,4′-dihydroxybiphenyl, 2,2 ′, 4,4′-tetramethyl- 3,3′-dihydroxybiphenyl, bis (4-hydroxy-3,5-dimethylphenyl) ether, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4-dimethylphenyl) ether, bis (3-hydroxy-2,4-dimethylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4- Dimethylphenyl) methane, bis (3-hydroxy-2,4-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane 1- (4-hydroxy-3,5-dimethylphenyl) -1- (3-hydroxy-2,4-dimethylphenyl) ethane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) ethane 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2- (4-hydroxy-3,5-dimethylphenyl) -2- (3-hydroxy-2,4-dimethylphenyl) propane 2,2-bis (3-hydroxy-2,4-dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, 1- (4-hydroxy-3,5- Dimethylphenyl) -1- (3-hydroxy-2,4-dimethylphenyl) cyclohexane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) cyclohexa Preferably, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, bis (4-hydroxy-3,5-dimethylphenyl) ether, bis (4-hydroxy- 3,5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1 -Bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane. Alternatively, bis (2-hydroxyphenyl) ether, (2-hydroxyphenyl) (3-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (3-hydroxyphenyl) ether, (3 -Hydroxyphenyl) (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ether, bis (2-hydroxy-3-methylphenyl) ether, bis (2-hydroxy-3-ethylphenyl) ether, (2- Hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) ether, (2-hydroxy-3-ethylphenyl) (3-hydroxy-4-ethylphenyl) ether, (2-hydroxy-3-methylphenyl) ) (4-Hydroxy-3-methylphenyl) Ether, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (3-hydroxy-4-methylphenyl) ether, bis (3-hydroxy-4-ethylphenyl) ether, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) ether, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxy- 3-methylphenyl) ether, bis (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (2- Hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) ether, bis (4-hydroxy -3-methylphenyl) methane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4- Hydroxy-3-methylphenyl) cyclohexane, bis (4-hydroxy-3-methylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5) -Dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, bis (4-hydroxy-2,3,5-trimethylphenyl) phenylmethane, 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) ) Phenylethane, bis (4-hydroxyphenyl) -1-phenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylpropane Bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) methoxymethane, 1,1-bis (4-hydroxyphenyl) -1-methoxyethane, 1,1- Bis (4-hydroxyphenyl) -1-methoxypropane, bis (4-hydroxy Eniru) dimethoxymethane, and the like.

  Among these, bis (4-hydroxy-3,5-dimethylphenyl) methane and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) are considered in consideration of the ease of production of the divalent hydroxyaryl component. Propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, or bis (4-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (2- Hydroxyphenyl) ether, bis (4-hydroxy-3-methylphenyl) ether, and bis (4-hydroxy-3-ethylphenyl) ether are particularly preferable, and a combination of a plurality of these divalent hydroxyaryl components can be used. is there.

<Dicarboxylic acid residue>
The dicarboxylic acid component which is a dicarboxylic acid residue in the polyarylate resin is represented by the following general formula (14).

Ar ¹² , Ar ¹³ , X ² , and k in the general formula (14) are as described above, and the dicarboxylic acid residues contained in the general formula (14) are represented by the following general formulas [I] to [VI]. The structure represented by can be illustrated. Here, k is an integer of 0 or more, but an integer of 0 to 5 is preferable from the viewpoint of electrical characteristics and scratch resistance, and more preferably 0 or 1.

From the viewpoint of wear resistance, k is preferably 1 and X ² is an oxygen atom.
It is represented by

Ar ¹² and Ar ¹³ in the general formula (15) are also as described above, but are preferably phenylene groups having no substituent.
Specific examples of the preferred dicarboxylic acid residue represented by the general formula (15) include diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,3′-dicarboxylic acid residue, diphenyl ether-2,4 ′. -Dicarboxylic acid residue, diphenyl ether-3,3'-dicarboxylic acid residue, diphenyl ether-3,4'-dicarboxylic acid residue, diphenyl ether-4,4'-dicarboxylic acid residue and the like. Among these, considering the simplicity of production of the dicarboxylic acid component, diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,4′-dicarboxylic acid residue, diphenyl ether-4,4′-dicarboxylic acid Residues are more preferred, and diphenyl ether-4,4′-dicarboxylic acid residues are particularly preferred.

Specific examples of the dicarboxylic acid residues other than those represented by the general formula (14) include phthalic acid residues, isophthalic acid residues, terephthalic acid residues, toluene-2,5-dicarboxylic acid residues, p Xylene-2,5-dicarboxylic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,3-dicarboxylic acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2 '-Dicarboxylic acid residue, biphenyl-4,4'-dicarboxylic acid residue can be mentioned, preferably phthalic acid residue, isophthalic acid residue, terephthalic acid residue, naphthalene-1,4-dicarboxylic acid residue , Naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-
A dicarboxylic acid residue, a biphenyl-4,4′-dicarboxylic acid residue, particularly preferably
It is an isophthalic acid residue or a terephthalic acid residue, and it is also possible to use a combination of these dicarboxylic acid residues.

  The polyarylate resin may be a resin containing another dicarboxylic acid component and enclosing the general formula (14) in a part of the structure. Specific examples of other dicarboxylic acid residues include adipic acid residues, suberic acid residues, sebacic acid residues, pyridine-2,3-dicarboxylic acid residues, pyridine-2,4-dicarboxylic acid residues, pyridine -2,5-dicarboxylic acid residue, pyridine-2,6-dicarboxylic acid residue, pyridine-3,4-dicarboxylic acid residue, pyridine-3,5-dicarboxylic acid residue, preferably, These are adipic acid residues and sebacic acid residues, and a plurality of these dicarboxylic acid residues can be used in combination.

  In addition, when it has the dicarboxylic acid residue represented by General formula (14) and the other dicarboxylic acid residue mentioned above, the dicarboxylic acid residue represented by General formula (14) is 70 as a number of repeating units. % Or more is preferable, 80% or more is more preferable, and 90% or more is particularly preferable. Most preferably, when having only the dicarboxylic acid residue represented by the general formula (14), that is, the dicarboxylic acid residue (14) represented by the general formula (14) is 100% as the number of repeating units. This is the case.

When the dicarboxylic acid residue represented by the general formula (15) and the other dicarboxylic acid residue described above are included, the dicarboxylic acid residue represented by the general formula (15) is usually used as the number of repeating units. From the viewpoint of wear resistance, it is preferably 70% or more,
80% or more is more preferable, and 90% or more is particularly preferable. Most preferably, it has only the dicarboxylic acid residue represented by the general formula (15), that is, the dicarboxylic acid residue represented by the general formula (15) is 100% as the number of repeating units. is there.

In the present invention, the amount of the other resin that may be used in combination with the polyester resin α is usually 50% by mass or more, preferably 70% by mass or more, and most preferably 80% by mass with respect to the total binder resin of the charge transport layer. On the other hand, it is usually 99% by mass or less, preferably 95% by mass or less. If the amount of other resins that may be used in combination is too small, sufficient wear resistance may not be obtained and electrical characteristics may be deteriorated. On the other hand, if the amount is too large, sufficient surface slipperiness may not be obtained. .
Further, the ratio of the polysiloxane structure represented by the general formula (1) to the total amount of the binder resin in the charge transport layer is an arbitrary amount as long as the effect of the present invention is not significantly impaired. From the viewpoint of surface slipperiness, usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass, while usually 5.0% by mass or less, From the viewpoint of characteristics and cost, it is preferably 3.0% by mass or less, more preferably 1.5% by mass or less. If the ratio of the polysiloxane structure to the total amount of the binder resin in the charge transport layer is too small, sufficient surface slipperiness may not be obtained. On the other hand, if it is too large, the electrical characteristics may be adversely affected. is there.

  As for the ratio of the binder resin to the charge transport material, the charge transport material is used in a ratio of 20 parts by mass or more with respect to 100 parts by mass of the binder resin. Among these, 30 parts by mass or more is preferable from the viewpoint of residual potential reduction, and 40 parts by mass or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used at a ratio of 150 parts by mass or less. Among these, 110 parts by mass or less is preferable from the viewpoint of compatibility between the charge transport material and the binder resin, 80 parts by mass or less is more preferable from the viewpoint of printing durability, and 70 parts by mass or less is most preferable from the viewpoint of scratch resistance.

The thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less, preferably 45 μm or less, from the viewpoint of long life, image stability, and high resolution. Is in the range of 30 μm or less.
<2-3-2. Single-layer type photosensitive layer>
The single-layer type photosensitive layer is formed using a binder resin in order to ensure film strength, in the same manner as the charge transport layer of the multilayer photoconductor, in addition to the charge generation material and the charge transport material. Specifically, a charge generation material, a charge transport material, and various binder resins are dissolved or dispersed in a solvent to prepare a coating solution, and on a conductive support (or an undercoat layer when an undercoat layer is provided). It can be obtained by coating and drying.

The types of the charge transport material and the binder resin and the use ratios thereof are the same as those described for the charge transport layer of the multilayer photoreceptor. The charge generating material is further dispersed in the charge transport medium comprising these charge transport material and binder resin.
As the charge generation material, the same materials as those described for the charge generation layer of the multilayer photoreceptor can be used. However, in the case of a photosensitive layer of a single-layer type photoreceptor, it is necessary to sufficiently reduce the particle size of the charge generating material. Specifically, the range is usually 1 μm or less, preferably 0.5 μm or less.

If the amount of the charge generating material dispersed in the single-layer type photosensitive layer is too small, sufficient sensitivity cannot be obtained, but if it is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. It is used in the range of usually 0.5% by mass or more, preferably 1% by mass or more, and usually 50% by mass or less, preferably 20% by mass or less based on the whole layer-type photosensitive layer.
In addition, the usage ratio of the binder resin and the charge generation material in the single-layer type photosensitive layer is such that the charge generation material is usually 0.1 parts by weight or more, preferably 1 part by weight or more, based on 100 parts by weight of the binder resin. It is 30 mass parts or less, Preferably it is set as the range of 10 mass parts or less.

  The film thickness of the single-layer type photosensitive layer is usually 5 μm or more, preferably 10 μm or more, and usually 100 μm or less, preferably 50 μm or less. Also in this case, known plasticizers for improving film formability, flexibility, mechanical strength, additives for suppressing residual potential, dispersion aids for improving dispersion stability, coatability Leveling agents and surfactants such as silicone oil, fluorine oil and other additives may be added to improve the viscosity.

<2-4. Other functional layers>
For the purpose of improving film forming properties, flexibility, coating properties, contamination resistance, gas resistance, light resistance, etc., in both the photosensitive layer and the layers constituting the photosensitive layer, both of the multilayer type photosensitive member and the single layer type photosensitive member. Additives such as well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, and visible light shielding agents may be included.

Further, for the purpose of reducing the frictional resistance and wear on the surface of the photoconductor, and increasing the transfer efficiency of the toner from the photoconductor to the transfer belt and paper, etc., the surface layer is made of fluorine resin, silicon resin, polyethylene resin, or the like. Particles made of this resin or inorganic compound particles may be contained in the surface layer. Alternatively, a layer containing these resins and particles may be newly formed as a surface layer.
Furthermore, it goes without saying that a layer for improving electrical properties and mechanical properties, such as an intermediate layer such as a barrier layer, an adhesive layer and a blocking layer, and a transparent insulating layer, may be provided as necessary.

<2-5. Formation method of each layer>
Each layer constituting these photoreceptors is formed by immersing, coating, spraying, nozzle coating, bar coating, roll coating, blade coating, etc., on a support, a coating solution obtained by dissolving or dispersing a substance to be contained in a solvent. In this method, the coating and drying steps are sequentially repeated for each layer.

  There are no particular restrictions on the solvent or dispersion medium used in the preparation of the coating solution, but specific examples include alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, dimethoxyethane and the like. Ethers, esters such as methyl formate and ethyl acetate, ketones such as acetone, methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, chloroform, 1,2-dichloroethane, 1,1, Chlorinated hydrocarbons such as 2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine , Nitrogen-containing compounds such as triethylenediamine, acetonitrile, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and kinds.

The amount of the solvent or dispersion medium used is not particularly limited, but considering the purpose of each layer and the properties of the selected solvent / dispersion medium, it is appropriate so that the physical properties such as solid content concentration and viscosity of the coating liquid are within a desired range. It is preferable to adjust.
For example, in the case of a charge transport layer layer of a single layer type photoreceptor and a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by mass or more, usually 5% by mass or more, preferably 10% by mass or more, Moreover, it is 40 mass% or less normally, Preferably it is set as the range of 35 mass% or less. Further, the viscosity of the coating solution is usually in the range of 10 cps or more, preferably 50 cps or more, and usually 500 cps or less, preferably 400 cps or less.

In the case of a charge generation layer of a multilayer photoreceptor, the solid content concentration of the coating solution is usually 0.1% by mass or more, preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. % Or less. The viscosity of the coating solution is usually 0.01 cps or more, preferably 0.1 cps or more, and usually 20 cps or less, preferably 10 cps or less.
Examples of the coating method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, and a curtain coating method. Other known coating methods can also be used.

The coating solution is preferably dried by touching at room temperature, followed by heating or drying in a temperature range of usually 30 ° C. or more and 200 ° C. or less for 1 minute to 2 hours, while still or blowing. The heating temperature may be constant or the heating may be performed while changing the temperature during drying.
<3. Image forming apparatus>
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention (an image forming apparatus 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. Examples of the charging device include a corona charging device such as a corotron and a scorotron, a direct charging device (contact type charging device) that charges a direct charging member to which a voltage is applied by contacting the photosensitive member surface, and a contact type charging device such as a charging brush. Often used. Examples of direct charging means include contact chargers such as charging rollers and charging brushes. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2. As the direct charging means, either charging with air discharge or injection charging without air discharge is possible. Moreover, as a voltage applied at the time of charging, it is possible to use only a direct current voltage or to superimpose an alternating current on a direct current.

  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 of 600 nm to 700 nm, slightly short wavelength, or monochromatic light with a wavelength of 380 nm to 500 nm. . Among these, it is preferable to use light having a short wavelength of 380 to 500 nm because the resolution becomes high. Among these, 405 nm monochromatic light is preferable.

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 insulating toner development, one-component conductive toner development, or two-component magnetic brush development, or a wet development method is used. be able to. 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 regulating 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 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. However, when there is little or almost no toner remaining on the surface of the photoreceptor, the cleaning device 6 may be omitted.

  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 have a configuration capable of performing, 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.
The electrophotographic photosensitive member 1 is combined with one or more of the charging device 2, the exposure device 3, the developing device 4, the transfer device 5, the cleaning device 6, and the fixing device 7 to form an integrated cartridge ( The electrophotographic photosensitive member cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. In this case, for example, when the electrophotographic photosensitive member 1 and other members are deteriorated, the electrophotographic photosensitive member cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic photosensitive member cartridge is mounted on the main body of the image forming apparatus. This facilitates maintenance and management of the image forming apparatus.

Specific embodiments of the present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist.
[Production of polyester resin]
Production Example 1 (Method for producing polyester resin (A))
Sodium hydroxide (5.03 g) and H ₂ O (238 ml) were weighed in a 300 mL beaker and dissolved with stirring. 2,3,5-trimethylphenol (0.17 g), 1,1-bis (4-hydroxy-3, methylphenyl) ethane (12.37 g), polysiloxane represented by the following general formula (1-5) Derivatives (average degree of polymerization of polysiloxane n = 32) (2.93 g) and benzyltriethylammonium chloride (0.14 g) were added in this order and dissolved with stirring, and then this aqueous alkaline solution was transferred to a 1 L reaction vessel.

Separately, a mixed solution of diphenyl ether-4,4′-dicarboxylic acid chloride (15.52 g) and dichloromethane (139 mL) was transferred into the dropping funnel.
While maintaining the external temperature of the reaction vessel at 20 ° C. and stirring the alkaline aqueous solution in the reaction vessel, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 1 hour, dichloromethane (197 mL) was added and stirring was continued for 3 hours. Thereafter, stirring was stopped and the mixture was allowed to stand for 30 minutes, and then the organic layer was separated. This organic layer was washed twice with 0.1 N aqueous sodium hydroxide solution (238 mL), then washed twice with 0.1 N hydrochloric acid (238 mL), and further demineralized water (238 mL). Was washed twice. Dilution was performed by adding 345 ml of methylene chloride, and the precipitate obtained by pouring into isopropanol (2700 ml) was removed by filtration and dried to obtain the desired polyester resin (A). The resulting polyester resin (A) had a viscosity average molecular weight of 49,600, and the content of polysiloxane in the polymer was 5.7% by mass. The structural formula of the obtained polyester resin (A) is shown below.

[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.

Production Example 2 (Method for producing polyester resin (B))
Sodium hydroxide (4.97 g) and H ₂ O (239 ml) were weighed in a 300 mL beaker and dissolved with stirring. 2,3,5-trimethylphenol (0.12 g), 1,1-bis (4-hydroxy-3, methylphenyl) ethane (12.21 g), polysiloxane represented by the above general formula (1-5) Derivatives (average degree of polymerization of polysiloxane n = 32) (4.09 g) and benzyltriethylammonium chloride (0.14 g) were added in this order and dissolved by stirring, and then this aqueous alkaline solution was transferred to a 1 L reaction vessel.
Separately, a mixed solution of diphenyl ether-4,4′-dicarboxylic acid chloride (15.33 g) and dichloromethane (140 mL) was transferred into the dropping funnel.

While maintaining the external temperature of the reaction vessel at 20 ° C. and stirring the alkaline aqueous solution in the reaction vessel, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 1 hour, dichloromethane (198 mL) was added and stirring was continued for 3 hours. Thereafter, stirring was stopped and the mixture was allowed to stand for 30 minutes, and then the organic layer was separated. This organic layer was washed twice with 0.1 N aqueous sodium hydroxide solution (239 mL), then washed twice with 0.1 N hydrochloric acid (239 mL), and further demineralized water (239 mL). Was washed twice. Diluted by adding 345 ml of methylene chloride, poured into isopropanol (2700 ml), the resulting precipitate was filtered off and dried to obtain the desired polyester resin (B). The obtained polyester resin (B) had a viscosity average molecular weight of 51,200, and the content of polysiloxane in the polymer was 6.1% by mass. The structural formula of the obtained polyester resin (B) is shown below.

Production Example 3 (Method for producing polyester resin (C))
Sodium hydroxide (4.72 g) and H ₂ O (244 ml) were weighed and dissolved in a 300 mL beaker while stirring. 2,3,5-trimethylphenol (0.29 g), 1,1-bis (4-hydroxy-3, methylphenyl) ethane (11.38 g), polysiloxane represented by the above general formula (1-5) Derivatives (average degree of polymerization of polysiloxane n = 32) (4.82 g) and benzyltriethylammonium chloride (0.13 g) were added in this order and dissolved with stirring, and then this aqueous alkaline solution was transferred to a 1 L reaction vessel.
Separately, a mixed solution of diphenyl ether-4,4′-dicarboxylic acid chloride (14.56 g) and dichloromethane (143 mL) was transferred into the dropping funnel.

While maintaining the external temperature of the reaction vessel at 20 ° C. and stirring the alkaline aqueous solution in the reaction vessel, the dichloromethane solution was dropped from the dropping funnel over 1 hour. After further stirring for 1 hour, dichloromethane (202 mL) was added and stirring was continued for 3 hours. Thereafter, stirring was stopped and the mixture was allowed to stand for 30 minutes, and then the organic layer was separated. This organic layer was washed twice with 0.1 N aqueous sodium hydroxide solution (424 mL), then washed twice with 0.1 N hydrochloric acid (244 mL), and further demineralized water (244 mL). Was washed twice. Diluted by adding 770 ml of methylene chloride, poured into isopropanol (4400 ml), the precipitate obtained was taken out by filtration and dried to obtain the desired polyester resin (C). The viscosity average molecular weight of the obtained polyester resin (C) was 39,300, and the content of polysiloxane in the polymer was 6.5% by mass. The structural formula of the obtained polyester resin (C) is shown below.

<Manufacture of photoreceptor sheet>
[Example 1]
The undercoat layer dispersion was produced as follows. That is, a rutile type titanium oxide having an average primary particle size of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were flowed at high speed. In a mixed solvent of methanol / 1-propanol in a mixed solvent of methanol / 1-propanol, which was introduced into a mixing kneader (“SMG300” manufactured by Kawata Co., Ltd.) and mixed at a high rotational speed of 34.5 m / sec. Then, a dispersion slurry of hydrophobized titanium oxide was obtained by dispersing with a ball mill. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam / bis (4-amino-3-methylcyclohexyl) methane / hexamethylenediamine / decamethylenedicarboxylic acid / octadecamethylenedicarboxylic acid The copolyamide pellets having a composition molar ratio of 60% / 15% / 5% / 15% / 5% are stirred and mixed while heating to dissolve the polyamide pellets, and then subjected to ultrasonic dispersion treatment. The weight ratio of methanol / 1-propanol / toluene is 7/1/2 and the hydrophobically treated titanium oxide / copolymerized polyamide is contained at a weight ratio of 3/1. A layer dispersion was obtained.

The undercoat layer-forming coating solution thus obtained was applied onto a polyethylene terephthalate sheet having aluminum deposited on the surface with a wire bar so that the film thickness after drying was 1.2 μm, dried and subtracted. A layer was provided.
Next, 10 parts by mass of oxytitanium phthalocyanine having a powder X-ray diffraction spectrum shown in FIG. 2 having a strong diffraction peak at 27.3 ° in the Bragg angle (2θ ± 0.2) in X-ray diffraction by CuKα ray is 1 In addition to 150 parts by mass of 2-dimethoxyethane, pulverization and dispersion treatment was performed with a sand grind mill to prepare a pigment dispersion. 160 parts by mass of the pigment dispersion thus obtained was added to 100 parts by mass of a 5 wt% 1,2-dimethoxyethane solution of polyvinyl butyral (trade name # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.), and an appropriate amount of 1,2 -Dimethoxyethane was added to finally prepare a dispersion having a solid concentration of 4.0% by mass.

This dispersion was applied onto the undercoat layer with a wire bar so that the film thickness after drying was 0.4 μm, and then dried to form a charge generation layer.
Next, as a charge transport material, a polyester resin (A) produced in Production Example 1, 50 parts by mass of a mixture consisting of a compound group of geometric isomers, the main component of which is a structure represented by the following general formula (16) 24 parts by mass, 76 parts by mass of polyester resin (D) (viscosity average molecular weight 41,000) having the following repetitive structure, 0.05 parts by mass of silicone oil as a leveling agent, and a mixed solvent of tetrahydrofuran and toluene (80 masses of tetrahydrofuran) %, Toluene 20% by mass) and 640 parts by mass to prepare a coating solution for forming a charge transport layer.

This charge transport layer forming coating solution is applied onto the above-described charge generation layer using an applicator so that the film thickness after drying is 20 μm, and dried at 125 ° C. for 20 minutes to form a charge transport layer. A photoreceptor sheet was prepared.
This photoreceptor sheet was evaluated for surface properties in a friction test and a wear test described later. In addition, the electrical characteristics were evaluated by a photoreceptor characteristic tester (model EPA8100 manufactured by Kawaguchi Electric Co., Ltd.) described later. The results are shown in Table-1.

[Friction test]
The friction coefficient was measured using a Heidon-14 type surface property tester manufactured by Shinto Kagaku Co., Ltd. At this time, a Teflon (registered trademark) sheet having a width of 10 mm and a length of 12 mm was used as the friction body, and measurement was performed under a load of 2.9 N and a sweep speed of 50 mm / min. 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.). The test conditions were measured by comparing the mass before and after the test with the wear amount after rotating 1000 times with a load of 500 g under an atmosphere of 23 ° C. and 50% RH. The results are shown in Table-1.

[Electrical characteristics]
Using an electrophotographic characteristic evaluation apparatus (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, pages 404-405) prepared according to the Electrophotographic Society measurement standard, the photoconductor is made into an aluminum drum. Attached to a cylindrical shape, the aluminum drum and the aluminum base of the photoconductor are connected, and then the drum is rotated at a constant rotational speed. went. At that time, the initial surface potential was -700 V, exposure was 780 nm, charge was 660 nm using monochromatic light, and the half-exposure amount (E _1/2 ) and 10 μJ required to reduce the surface potential from −700 V to −350 V. Residual potential (Vr) when irradiated with / cm ² was measured. The measurement environment was a temperature of 35 ° C. and a relative humidity of 90% (H / H). The results are shown in

[Comparative Example 1]
A photoreceptor sheet was produced in the same manner as in Example 1 except that the polyester resin used in the coating liquid for forming the charge transport layer in Example 1 was only the polyester resin (D) described above. This photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 1.
[Example 2]
In place of the polyester resin (A) in Example 1, 18 parts by mass of the polyester resin (B) produced in Production Example 2 and 82 parts by mass of the polyester resin (D) were used. Thus, a photoreceptor was produced. The obtained photoreceptor was subjected to a friction test, a wear test, and an evaluation of electrical characteristics under the same conditions as in Example 1. The results are shown in

[Comparative Example 2]
In place of the polyester resin (A) in Example 1, the polyester resin (C) produced in Production Example 3 was used in an amount of 16 parts by mass, and the polyester resin (D) was used in an amount of 84 parts by mass. Thus, a photoreceptor was produced. The obtained photoreceptor was subjected to a friction test, a wear test, and an evaluation of electrical characteristics under the same conditions as in Example 1. The results are shown in Table-1.

From the above results, it can be seen that by using the photoreceptor of the present invention, it is possible to obtain an electrophotographic photoreceptor excellent in surface characteristics while maintaining electrical characteristics, and further excellent in mechanical properties, particularly in abrasion resistance. .

  The present invention can be used in any field where an electrophotographic photosensitive member is used, and is particularly suitable for use in an image forming apparatus such as a printer or a copying machine.

1 Electrophotographic photoreceptor 2 Charging device (charging roller)
DESCRIPTION OF SYMBOLS 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (pressure roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper

Claims (6)

An electrophotographic photoreceptor having at least a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains a polyester resin that satisfies the following conditions (A) to (C).
(A) having a polysiloxane structure represented by the following general formula (1) on at least a part of the polymer terminal (B) having a repeating structure represented by the following general formula (2) (C) viscosity average molecular weight 42,000 to 80,000

(In General Formula (1), R ^{a to} R ^e each independently represents an alkyl group which may have a substituent, or an aromatic group which may have a substituent, and n is 1 to 500. Indicates an integer.)

(In General Formula (2), R ^{1 to} R ⁸ are each independently a hydrogen atom, an alkyl group that may have a substituent having 1 to 20 carbon atoms, an alkoxyl group, or an optionally substituted aromatic group. X ¹ represents any one of a group, X ¹ represents a single bond, an alkylene group, —CR ⁹ R ¹⁰ —, an oxygen atom, or a sulfur atom, and R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a carbon number of 1 -20 alkyl group, an aromatic group which may have a substituent, or a group in which R ⁹ and R ¹⁰ are bonded to each other to form a ring which may have a substituent. ) The electrophotographic photoreceptor according to claim 1, wherein the general formula (2) is represented by the following general formula (3).

(In General Formula (3), R ^{1 to} R ⁸ are each independently a hydrogen atom, an alkyl group that may have a substituent having 1 to 20 carbon atoms, an alkoxyl group, or an optionally substituted aromatic group. R ⁹ and R ¹⁰ each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aromatic group which may have a substituent, or R ⁹ and R ¹⁰ are Any one of the groups that are bonded to form an optionally substituted ring is shown.) The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer further contains a compound represented by the following general formula (4).

(In General Formula (4), Ar ^{1 to} Ar ⁶ each independently represent 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. Q represents a direct bond or a divalent residue, and R ^{11 to} R ¹⁸ each independently have a hydrogen atom or a substituent. N ^{1 to} n ⁴ each independently represents an integer of 0 to 4; and a preferable alkyl group, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent. Ar ^{1 to} Ar ⁶ may be bonded to each other to form a cyclic structure.) The photosensitive layer contains oxytitanium phthalocyanine having a clear peak at a Bragg angle 2θ ± 0.2 ° of 27.3 ° in powder X-ray diffraction using CuKα characteristic X-rays. Item 4. The electrophotographic photosensitive member according to any one of Items 1 to 3.   5. The electrophotographic photosensitive member according to claim 1, charging means for charging the electrophotographic photosensitive member, and image exposure of the charged electrophotographic photosensitive member to form an electrostatic latent image. An electrophotographic cartridge comprising: an image exposure unit; a developing unit that develops the electrostatic latent image with toner; and a transfer unit that transfers the toner to a transfer target.   5. The electrophotographic photosensitive member according to claim 1, charging means for charging the electrophotographic photosensitive member, and exposure means for forming an electrostatic latent image by exposure to the charged electrophotographic photosensitive member. And a developing unit that develops the electrostatic latent image with toner, a transfer unit that transfers the toner to a transfer target, and a fixing unit that fixes the toner transferred to the transfer target. An image forming apparatus.

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