JP2008203802A - Electrophotographic photoreceptor, image forming apparatus used therefor, and electrophotographic cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having excellent wear resistance. <P>SOLUTION: Regarding the electrophotographic photoreceptor having a photosensitive layer on a conductive support, the photosensitive layer comprises: a polyester resin including a repeating structure represented by formula (1); and the polyester resin composed of a structure different from that of the above resin and at least one resin selected from the group consisting of a polycarbonate resin, and the second resin includes a repeating structure represented by formula (2). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member used for a copying machine, a printer, and the like, and more particularly to an electrophotographic photosensitive member having excellent durability, and an image forming apparatus and an electrophotographic cartridge using the same.

Electrophotographic technology is widely used in fields such as copiers and various printers because of its immediacy and high quality images.
For the electrophotographic photoreceptor (hereinafter referred to as “photoreceptor” as appropriate) which is the core of the electrophotographic technology, an organic photoconductive material having advantages such as non-polluting, easy film formation and easy production was used. A photoconductor is used.

  As a photoconductor using an organic photoconductive material, a so-called dispersion type photoconductor in which a photoconductive fine powder is dispersed in a binder resin, and a laminated type photoconductive layer in which a charge generation layer and a charge transport layer are laminated. Are known. In the laminated photosensitive layer, a highly sensitive photoreceptor can be obtained by combining a highly efficient charge generating substance and charge transporting substance, a highly safe photoreceptor having a wide material selection range, and a photosensitive layer. The layer can be easily formed by coating, has high productivity, and is advantageous in terms of cost. Therefore, it is the mainstream of photoreceptors, and has been developed and put into practical use.

  Since the electrophotographic photosensitive member is repeatedly used in an electrophotographic process, that is, a cycle of charging, exposure, development, transfer, cleaning, static elimination, etc., it is deteriorated by various stresses during that time. Such deterioration includes, for example, strong oxidation ozone and NOx generated from a corona charger used as a charger, which causes chemical damage to the photosensitive layer, or a carrier generated by image exposure or static elimination light. Chemical and electrical deterioration such as the fact that the photosensitive layer composition is decomposed by flowing in the photosensitive layer or by external light.

  In addition to this, mechanical degradation such as abrasion of the photosensitive layer surface due to rubbing of the cleaning blade, magnetic brush, developer, contact with the transfer member or paper, scratches, and film peeling. is there. In particular, the damage generated on the surface of the photosensitive layer tends to appear on the image and directly impairs the image quality, which is a major factor that limits the life of the photoreceptor. That is, in order to develop a long-life photoconductor, it is desirable to increase the mechanical strength as well as the electrical and chemical durability.

In the case of a general photoreceptor having no functional layer such as a surface protective layer, it is the photosensitive layer that receives such a load. The photosensitive layer is usually composed of a binder resin and a photoconductive substance, and the binder resin substantially determines the strength. However, since the doping amount of the photoconductive substance is considerably large, the conventional technology has not yet provided the photosensitive layer with sufficient mechanical strength.
Examples of the binder resin for the photosensitive layer include, for example, 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, and various types. The thermosetting resin is 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, see Patent Documents 1 to 4).

On the other hand, a technique of an electrophotographic photoreceptor using a polyarylate resin marketed as a trade name “U-polymer” as a binder resin is disclosed, and among them, sensitivity is particularly excellent as compared with polycarbonate. (For example, refer to Patent Document 5).
In addition, a technique for an electrophotographic photoreceptor using a polyarylate resin using a dihydric phenol component having a specific structure as a binder resin is disclosed, and the solution stability at the time of producing the photoreceptor is improved, especially the mechanical strength. It is known that the wear resistance is excellent (see, for example, Patent Documents 6 and 7).
JP 50-98332 A JP 59-71057 A JP 59-184251 JP-A-5-21478 JP-A-56-135844 Japanese Patent Laid-Open No. 3-6567 Japanese Patent Laid-Open No. 10-288845

However, conventional photoconductors suffer from disadvantages such as surface wear and scratches caused by practical loads such as friction caused by toner developer, transfer member, paper, cleaning member (blade), etc. have. For this reason, the present situation is that the printing performance is limited in practical use.
The present invention has been made to solve such problems. That is, an object of the present invention is to provide an electrophotographic photoreceptor excellent in wear resistance, and an image forming apparatus and an electrophotographic cartridge using the electrophotographic photoreceptor.

As a result of intensive studies, the present inventors have at least one selected from the group consisting of a polyester resin having a specific repeating structure in the photosensitive layer and a specific repeating structure different from the resin, and a polyester resin and a polycarbonate resin. It has been found that excellent mechanical durability can be obtained by using the resin together, and the present invention has been completed.
That is, the gist of the present invention is that, in an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, the photosensitive layer includes a polyester resin (hereinafter referred to as “first”) having a repeating structure represented by the following formula (1). Resin ”) and at least one resin selected from the group consisting of polyester resin and polycarbonate resin (hereinafter referred to as“ second resin ”) having a structure different from that of the first resin, 2 resin exists in an electrophotographic photosensitive member containing a repeating structure represented by the following formula (2) (Claim 1), and at this time, the total of the first resin and the second resin The weight of the second resin with respect to the weight is preferably 1% by weight or more and 70% by weight or less (Claim 2).

(Wherein ^(1), Ar 1 ~Ar ⁴ each independently have a substituent represents also arylene group, ^{X 1} represents a divalent group (including a single bond), ^{X 2} Represents a divalent group having 3 or less atoms (including a single bond).

(In the formula (2), R ¹ and R ² each independently represent a hydrogen atom or an alkyl group, and R ³ and R ⁴ each independently represent an alkyl group, provided that R ^{1 to} R ⁴ are They are not all the same group.)
The second resin is preferably a polycarbonate resin (Claim 3), and the repeating structure represented by the formula (2) is preferably represented by the following formula (3) (Claim). 4) The weight ratio of the repeating structure represented by the formula (3) contained in the polycarbonate resin to the polycarbonate resin is preferably 70% by weight or more (Claim 5).

Another subject matter of the present invention lies in the electrophotographic photosensitive member according to the present invention, wherein the electrostatic latent image is recorded by exposure with monochromatic light having a wavelength of 380 to 500 nm.
Still another subject matter of the present invention is an electrophotographic photosensitive member according to the present invention, a charging means for charging the electrophotographic photosensitive member, and image exposure is performed on the charged electrophotographic photosensitive member to form an electrostatic latent image. An image forming apparatus comprising: an image exposing unit that performs development, a developing unit that develops the electrostatic latent image with toner, and a transfer unit that transfers the toner to a transfer target (claim 7). In the image forming apparatus, it is preferable that the exposure wavelength of the image exposure unit for forming the electrostatic latent image is monochromatic light of 380 to 500 nm.

  Still another subject matter of the present invention is an electrophotographic photosensitive member according to the present invention, a charging means for charging the electrophotographic photosensitive member, and image exposure is performed on 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. Item 9).

  According to the present invention, an electrophotographic photoreceptor excellent in abrasion resistance and capable of forming a high-quality image even when used repeatedly, and an image forming apparatus and an electrophotographic cartridge using the electrophotographic photoreceptor are obtained. be able to.

Hereinafter, the best mode for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with any modifications within the scope of the gist thereof.
[I. Electrophotographic photoreceptor]
The electrophotographic photosensitive member (photosensitive member) of the present invention has a photosensitive layer on a conductive support. The photosensitive layer comprises a polyester resin having a repeating structure represented by the following formula (1) (hereinafter referred to as “first resin”), and a polyester resin and a polycarbonate resin having a structure different from the first resin. At least one resin selected from the group consisting of (hereinafter referred to as “second resin”), and the second resin includes a repeating structure represented by the following formula (2).

(Wherein ^(1), Ar 1 ~Ar ⁴ each independently have a substituent represents also arylene group, ^{X 1} represents a divalent group (including a single bond), ^{X 2} Represents a divalent group having 3 or less atoms (including a single bond).

(In the formula (2), R ¹ and R ² each independently represent a hydrogen atom or an alkyl group, and R ³ and R ⁴ each independently represent an alkyl group, provided that R ^{1 to} R ⁴ are They are not all the same group.)
The first resin and the second resin usually function as a binder resin in the photosensitive layer.
[I-1. Binder resin]
The photoreceptor of the present invention contains a first resin and a second resin in the photosensitive layer. Specifically, when the photosensitive layer is composed of a single layer, the photosensitive layer contains the first resin and the second resin, and when the photosensitive layer is composed of two or more layers, One or more layers contain a first resin and a second resin. Further, the layer containing the first resin and the second resin may contain a resin other than the first resin and the second resin.
[I-1-1. First resin]
The first resin contained in the photosensitive layer of the photoreceptor of the present invention is a polyester resin including a repeating structure represented by the following formula (1).

(Wherein ^(1), Ar 1 ~Ar ⁴ each independently have a substituent represents also arylene group, ^{X 1} represents a divalent group (including a single bond), ^{X 2} Represents a divalent group having 3 or less atoms (including a single bond).
In the formula (1), Ar ^{1 to} Ar ⁴ each independently represent an arylene group. The number of carbon atoms of Ar ^{1 to} Ar ⁴ is arbitrary as long as the effects of the present invention are not significantly impaired. However, the number of carbon atoms of Ar ¹ and Ar ² is usually 6 or more and 20 or less, preferably 12 or less, and particularly preferably 7. Moreover, Ar ³ and Ar ⁴ usually have 6 or more and 20 or less carbon atoms, preferably 12 or less, and particularly preferably 6.

Further, the number of rings Ar ^{1 to} Ar ⁴ is arbitrary as long as the effects of the present invention are not significantly impaired, but it is usually 1 or more, usually 3 or less, preferably 2 or less, particularly preferably 1.
Specific examples of these Ar ^{1 to} Ar ⁴ include a phenylene group, a naphthylene group, a 3-methylphenylene group, and a 3-phenylphenylene group.
Moreover, the arylene group which comprises Ar < ¹ > -Ar < ⁴ > may have a substituent each independently. Specific examples of the substituent include an alkyl group, an aryl group, a halogen group, and an alkoxy group. Among these, in consideration of mechanical properties as a binder resin for the photosensitive layer and solubility in the coating solution for forming the photosensitive layer, the aryl group is preferably a phenyl group, a naphthyl group, or the like, and the halogen group is a fluorine atom or chlorine. An atom, a bromine atom, an iodine atom and the like are preferable, and examples of the alkoxy group include a methoxy group, an ethoxy group and 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, and specifically a methyl group is preferable. Further, there is no particular limitation on the number of substituents Yes of Ar ¹ to Ar ⁴ each, preferably three or less, more preferably 2 or less, particularly preferably 1 or less.

Further, in the formula (1), when Ar ¹ and Ar ² have a substituent, Ar ¹ and Ar ² are preferably the same arylene group having the same substituent, and phenylene having a methyl group as a substituent More preferably, it is a group. Ar ³ and Ar ⁴ are preferably the same arylene group, and particularly preferably a phenylene group having no substituent.

In the formula (1), X ¹ represents a divalent group. The divalent group here includes a single bond. Preferable examples of X ¹ include a sulfur atom, an oxygen atom, a sulfonyl group, a cycloalkylene group, —CR ^a R ^b — and the like. Here, R ^a and R ^b each independently represent a hydrogen atom, an alkyl group, an aryl group, a halogen group, or an alkoxy group. Further, among R ^a and R ^b, the phenyl group, naphthyl group, etc. are preferable as the aryl group, considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer. As the halogen group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like are preferable, and as the alkoxy group, a methoxy group, an ethoxy group, a butoxy group and the like are preferably exemplified. In addition, when R ^a or R ^b is an alkyl group, the 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.

Furthermore, considering the simplicity of production of the divalent hydroxy compound used when producing the polyester resin which is the first resin according to the present invention, examples of preferred groups as X ¹ include —O— and —S. _{-, - SO -, - SO} 2 -, - CO -, - CH 2 -, - CH (CH 3) -, - C (CH 3) 2 -, include cyclohexylidene. Among these, —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ —, and cyclohexylidene are preferable, and —CH ₂ —, —CH (CH ₃ ) —, cyclohexylene are particularly preferable. Den.

In the formula (1), X ² represents a divalent group having 3 or less atoms. The divalent group here includes a single bond. Examples of suitable X ² include a single bond, —O—, —S—, —SO—, —SO ₂ —, —CO—, —CH ₂ — and the like. Furthermore, considering the mechanical properties of the polyester resin of the present invention and the ease of production, examples of preferred groups for X ² include a single bond, —O—, and —CH ₂ —. Among these, -O- is most preferable in terms of mechanical properties.

  By the way, the repeating structure represented by the above formula (1) is represented by a divalent hydroxy residue (partial structure represented by the following formula (4)) and a dicarboxylic acid residue (the following formula (5)). Partial structure). The structures of these divalent hydroxy residues and dicarboxylic acid residues have various effects on the polyester resin of the present invention. Therefore, it is desirable that the structures of the divalent hydroxy residue and the dicarboxylic acid residue are appropriately preferred.

(In the formulas (4) and (5), Ar ^{1 to} Ar ⁴ each independently represents an arylene group which may have a substituent, and X ¹ represents a divalent group (including a single bond). X ² represents a divalent group having 3 or less atoms (including a single bond).
Hereinafter, preferred structures of the above divalent hydroxy residue and dicarboxylic acid residue will be described.

First, the divalent hydroxy residue is represented by the formula (4). In the formula (4), Ar ¹ , Ar ² and X ¹ are the same as those described in the formula (1).
Among the divalent hydroxy residues represented by the above formula (4), a divalent phenol residue represented by the following formula (6) is particularly preferable.

(In Formula (6), Ar ¹¹ and Ar ¹² each independently represent a phenylene group which may have a substituent, and R ⁵ represents a hydrogen atom or a methyl group.)
In the formula (6), Ar ¹¹ and Ar ¹² each independently represent a phenylene group which may have a substituent. At this time, the substituents of Ar ¹¹ and Ar ¹² are the same as those described above as the substituents of Ar ^{1 to} Ar ⁴ .

In the formula (6), R ⁵ represents a hydrogen atom or a methyl group.
Specific examples of the structure represented by the formula (6) include a dihydric phenol residue having a structure in which a hydrogen atom is removed from a hydroxyl group of a dihydric phenol compound exemplified below.
That is, when R ⁵ is a hydrogen atom, examples of the dihydric phenol compound corresponding to the dihydric phenol residue represented by the formula (6) include 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, bis (4-hydroxy-3-methylphenyl) methane, bis (4-hydroxy-3-ethylphenyl) methane, bis (4-hydroxy-3, 5-dimethylphenyl) methane, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy-2, - dimethylphenyl) methane, bis (3-hydroxy-2,4-dimethylphenyl) methane and the like.

When R ⁵ is a methyl group, examples of the dihydric phenol compound corresponding to the dihydric phenol residue represented by the formula (6) include 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) 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, 1,1-bis (4 Hydroxy-3-ethylphenyl) ethane, 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 and the like.

Among these, considering the simplicity of production of the dihydric phenol compound, when R ⁵ is a hydrogen atom, bis (4-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, bis ( 2-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, bis (4-hydroxy-3-ethylphenyl) methane, bis (4-hydroxy-3,5-dimethylphenyl) methane are particularly preferred. .

When R ⁵ 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, 1,1-bis (4-hydroxy-3-ethylphenyl) ethane, 1,1-bis (4-hydroxy) -3,5-dimethylphenyl) ethane is preferred.

In formula (4), when an example of a divalent hydroxy residue not included in formula (6) is given, a divalent hydroxy residue having a structure in which a hydrogen atom is removed from a hydroxyl group of a divalent hydroxy compound exemplified below Is mentioned.
That is, examples of the divalent hydroxy compound corresponding to the divalent hydroxy residue represented by the formula (4) include 4,4′-dihydroxybiphenyl, 3,3 ′, 5,5′-tetramethyl-4. , 4′-dihydroxybiphenyl, 2,4,3 ′, 5′-tetramethyl-3,4′-dihydroxybiphenyl, 2,2 ′, 4,4′-tetramethyl-3,3′-dihydroxybiphenyl, 1 , 1-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2- (4-hydroxy-3,5-dimethylphenyl) -2- (3-hydroxy-2,4-dimethylphenyl) propane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) propane, 2, 2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 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,
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,
1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, -(4-hydroxy-3,5-dimethylphenyl) -1- (3-hydroxy-2,4-dimethylphenyl) cyclohexane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) cyclohexane,
Bis (2-hydroxyphenyl) ether, (2-hydroxyphenyl) (3-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (3-hydroxyphenyl) ether, (3-hydroxy Phenyl) (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-hydroxy-3,5-dimethylphenyl) ether, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy- 2,4-dimethylphenyl) ether, bis (3-hydroxy-2,4-dimethylphenol Le) ether, bis (4-hydroxyphenyl) ketone, and the like.

  Among these, 4,4′-dihydroxybiphenyl, 2,2-bis- (4-hydroxyphenyl) propane, bis- (4-hydroxyphenyl) phenylmethane are considered in consideration of the convenience of production of the divalent hydroxy compound. 1,1-bis- (4-hydroxyphenyl) -1-phenylethane, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, 2,2-bis (4-hydroxy- 3-methylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxy-3) , 5-dimethylphenyl) cyclohexane or bis (4-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydro Siphenyl) ether, bis (2-hydroxyphenyl) ether, bis (4-hydroxy-3-methylphenyl) ether, bis (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxy-3,5-dimethyl) Phenyl) ether is preferred.

In addition, the bivalent hydroxy compound and divalent hydroxy residue mentioned above may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.
On the other hand, the dicarboxylic acid residue is represented by the formula (5). In the formula (5), Ar ³ , Ar ⁴ and X ² are the same as those described in the formula (1). Among the dicarboxylic acid residues having a structure represented by the above formula (5), it is particularly preferable that X ² is —O— as shown in the following formula.

Specific examples thereof include a dicarboxylic acid residue having a structure in which a hydroxyl group is removed from a carboxyl group of a dicarboxylic acid compound exemplified below.
That is, for example, examples of dicarboxylic acid compounds corresponding to the dicarboxylic acid residue represented by the formula (5) include diphenyl ether-2,2′-dicarboxylic acid, diphenyl ether-2,3′-dicarboxylic acid, diphenyl ether- Examples include 2,4′-dicarboxylic acid, diphenyl ether-3,3′-dicarboxylic acid, diphenyl ether-3,4′-dicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid. Among these, diphenyl ether-2,2′-dicarboxylic acid, diphenyl ether-2,4′-dicarboxylic acid, and diphenyl ether-4,4′-dicarboxylic acid are preferable, considering the simplicity of production of the dicarboxylic acid compound, and diphenyl ether -4,4'-dicarboxylic acid is particularly preferred.

In addition, the dicarboxylic acid compound and dicarboxylic acid residue mentioned above may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.
Therefore, it is preferable to appropriately select the aforementioned Ar ^{1 to} Ar ⁴ and X ¹ and X ² so that the structures of the divalent hydroxy residue and the dicarboxylic acid residue are the preferable structures.
From the above points, among the polyester resins of the present invention described above, those including a repeating structure represented by the following formula (7) are particularly preferable.

(In formula (7), Ar ^3p , Ar ^4p , Ar ¹¹ and Ar ¹² each independently represent a phenylene group which may have a substituent, and R ⁵ represents a hydrogen atom or a methyl group.)
In the formula (7), Ar ¹¹ , Ar ¹² and R ⁵ are the same as those described in the formula (6).
In the formula (7), Ar ^3p and Ar ^4p each independently represent a phenylene group which may have a substituent. At this time, the substituents of Ar ^3p and Ar ^4p are the same as those described above as the substituents of Ar ^{1 to} Ar ⁴ .

Moreover, the repeating structure represented by the formula (1) may be one type in the polyester resin of the present invention, or two or more types may be used in any combination and ratio. Therefore, the above divalent hydroxy residue and dicarboxylic acid residue may be used alone or in combination of two or more in any combination and ratio. Ar ^{1 to} Ar ⁴ and X ¹ and X ² may each be used alone or in combination of two or more in any combination and ratio.

Furthermore, the polyester resin of the present invention may contain a component other than the divalent hydroxy residue represented by the above formula (4) or the dicarboxylic acid residue represented by the formula (5) as its partial structure. For example, a resin that includes another dicarboxylic acid residue of the dicarboxylic acid residue represented by the formula (5) and encapsulates the repeating structure of the formula (1) in a part of the structure may be used. Specific examples of other dicarboxylic acid residues include adipic acid residues, suberic acid residues, sebacic acid residues, phthalic acid residues, isophthalic acid residues, terephthalic acid residues, toluene-2,5-dicarboxylic acid residue,
p-xylene-2,5-dicarboxylic acid residue, pyridine-2,3-dicarboxylic acid residue, pyridine-2,4-dicarboxylic acid residue, pyridine-2,5-dicarboxylic acid residue, pyridine-2, 6-dicarboxylic acid residue, pyridine-3,4-dicarboxylic acid residue, pyridine-3,5-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, and the like. Among these, preferably, adipic acid residue, sebacic acid residue, phthalic acid residue, isophthalic acid residue, terephthalic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,6-dicarboxylic acid residue Group, biphenyl-2,2′-dicarboxylic acid residue, biphenyl-4,4′-dicarboxylic acid residue, and particularly preferred are isophthalic acid residue and terephthalic acid residue. In addition, as for the repeating unit (residue) other than the divalent hydroxy residue represented by the above formula (4) or the dicarboxylic acid residue represented by the formula (5), one type may be used alone, or two types may be used. The above may be used in any combination and ratio.

  However, in the polyester resin of the present invention, it is preferable that the number of repeating units other than the divalent hydroxy residue represented by the formula (4) or the dicarboxylic acid residue represented by the formula (5) is small. Therefore, it is preferable that the amount of divalent hydroxy residue other than that represented by formula (4) and dicarboxylic acid residue other than that represented by formula (5) is also small. Although the specific ratio is not limited, for example, with respect to the dicarboxylic acid residue, the ratio of the dicarboxylic acid residue represented by the formula (5) in the total amount of the dicarboxylic acid residue is usually 70 by the ratio of the number of repeating units. % Or more, preferably 80% or more, more preferably 90% or more, and particularly preferably 100%.

Next, the manufacturing method of the polyester resin of this invention is demonstrated. As a method for producing the polyester resin of the present invention, a known polymerization method can be used. Examples thereof include an interfacial polymerization method, a melt polymerization method, and a solution polymerization method.
For example, in the case of production by the interfacial polymerization method, a solution in which a divalent hydroxy compound is dissolved in an alkaline aqueous solution and a halogenated hydrocarbon solution in which an aromatic dicarboxylic acid chloride is dissolved are mixed. At this time, a quaternary ammonium salt or a quaternary phosphonium salt may be present as a catalyst. The polymerization temperature is preferably in the range of 0 to 40 ° C., and the polymerization time is preferably in the range of 2 to 20 hours from the viewpoint of productivity. After completion of the polymerization, the water phase and the organic phase are separated, and the polymer dissolved in the organic phase is washed and recovered by a known method, whereby the intended resin can be obtained.

Examples of the alkali component used in the interfacial polymerization method include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. As the usage-amount of an alkali, the range of 1.01-3 times equivalent of the phenolic hydroxyl group contained in a reaction system is preferable.
Examples of the halogenated hydrocarbon include dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, dichlorobenzene, and the like. In addition, a halogenated hydrocarbon may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, examples of the quaternary ammonium salt or quaternary phosphonium salt used as the catalyst include, for example, salts of tertiary alkylamines such as tributylamine and trioctylamine such as hydrochloric acid, bromic acid and iodic acid; Trimethylammonium chloride, benzyltributylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, trioctylmethylammonium chloride, tetrabutylphosphonium bromide, triethyloctadecylphosphonium bromide, N-laurylpyridinium chloride, laurylpicolinium chloride, etc. Is mentioned. In addition, a catalyst may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and ratios.

  In the interfacial polymerization method, a molecular weight regulator can be used. Examples of the molecular weight regulator include phenol, o, m, p-cresol, o, m, p-ethylphenol, o, m, p-propylphenol, o, m, p- (tert-butyl) phenol, and pentyl. Alkylphenols such as phenol, hexylphenol, octylphenol, nonylphenol, 2,6-dimethylphenol derivatives and 2-methylphenol derivatives, monofunctional phenols such as o, m, p-phenylphenol, acetic acid chloride, butyric acid chloride, octyl Examples thereof include monofunctional acid halides such as acid chloride, benzoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, benzenephosphonyl chloride, and substituted products thereof.

  Among these molecular weight regulators, o, m, p- (tert-butyl) phenol, 2,6-dimethylphenol derivatives, 2-methylphenol derivatives are preferred because of their high molecular weight controllability and solution stability. Particularly preferred are p- (tert-butyl) phenol, 2,3,6-tetramethylphenol, and 2,3,5-tetramethylphenol. In addition, a molecular weight regulator may also be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  Further, in the polyester resin of the present invention, the viscosity average molecular weight is usually 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, and usually 300 so as to be suitable for coating and forming a photosensitive layer. , 000 or less, preferably 200,000 or less, more preferably 100,000 or less. If the viscosity average molecular weight is less than 10,000, the mechanical strength of the resin may be lowered and may not be practical. If the viscosity average molecular weight is more than 300,000, it is difficult to apply and form the photosensitive layer to an appropriate film thickness. There is a possibility.

[I-1-2. Second resin]
The second resin contained in the photosensitive layer of the photoreceptor of the present invention is at least one resin selected from the group consisting of a polyester resin and a polycarbonate resin having a structure different from that of the first resin, The resin is a resin including a repeating structure represented by the following formula (2).

In the formula (2), R ¹ and R ² each independently represent a hydrogen atom or an alkyl group, and R ³ and R ⁴ each independently represent an alkyl group. However, R ^{1 to} R ⁴ are not all the same group. When R ¹ and R ² are alkyl groups, the structure may be linear, branched, or cyclic, but a linear or branched structure may be used. The alkyl group having is preferable. R ^1, R ² carbon atoms when it is an alkyl group, 1 to 12, more preferably a 1-6, more preferably an alkyl group having 1 to 3 carbon atoms, particularly a methyl group preferable. R ¹ and R ² each independently represents a hydrogen atom or an alkyl group, but preferably at least one is a hydrogen atom. R ³ and R ⁴ are alkyl groups, and the structure may be linear, branched or cyclic, but has a linear or branched structure. Alkyl groups are preferred. 1-6 are preferable, as for carbon number of the alkyl group of R < ³ >, R < ⁴ >, More preferably, it is 1-3, and especially a methyl group is preferable.

  The second resin is not particularly limited as long as it is at least one resin selected from the group consisting of a polyester resin and a polycarbonate resin, which includes a repeating structure represented by the formula (2), and the effect of the present invention is not significantly impaired. Any resin can be used. As the second resin, at least one of a polyester resin and a polycarbonate resin including a repeating structure represented by the formula (2) may be used, and both the polyester resin and the polycarbonate resin may be used.

Examples of the polycarbonate resin that can be used as the second resin include those having a structural unit derived from the following bifunctional phenol compound.
That is, for example, as the bifunctional phenol compound, bis- (4-hydroxy-3-methylphenyl) methane, bis- (4-hydroxy-2-methylphenyl) methane, 1,1-bis- (4-hydroxy) -3-methylphenyl) ethane, 1,1-bis- (4-hydroxy-2-methylphenyl) ethane, 1,1-bis- (4-hydroxy-3-ethylphenyl) ethane, 1,1-bis- (4-hydroxy-3-propylphenyl) ethane, 1,1-bis- (4-hydroxy-3-isopropylphenyl) ethane, 1,1-bis- (4-hydroxy-3-butylphenyl) ethane, 1, 1-bis- (4-hydroxy-3-isobutylphenyl) ethane, 1,1-bis- (4-hydroxy-3-sec-butylphenyl) ethane, 1,1-bis- 4-hydroxy-3-pentylphenyl) ethane, 1,1-bis- (4-hydroxy-3-isopentylphenyl) ethane, 1,1-bis- (4-hydroxy-3-neopentylphenyl) ethane, 1 , 1-bis- (4-hydroxy-3-methylphenyl) propane, 1,1-bis- (4-hydroxy-2-methylphenyl) propane, 1,1-bis- (4-hydroxy-3-ethylphenyl) ) Propane, 1,1-bis- (4-hydroxy-3-propylphenyl) propane, 1,1-bis- (4-hydroxy-3-isopropylphenyl) propane, 1,1-bis- (4-hydroxy-) 3-butylphenyl) propane, 1,1-bis- (4-hydroxy-3-isobutylphenyl) propane, 1,1-bis- (4-hydroxy-3-pen) Ruphenyl) propane, 1,1-bis- (4-hydroxy-3-isopentylphenyl) propane, 1,1-bis- (4-hydroxy-3-neopentylphenyl) propane, 2,2-bis- (4 -Hydroxy-3-ethylphenyl) propane, 2,2-bis- (4-hydroxy-3-propylphenyl) propane, 2,2-bis- (4-hydroxy-3-isopropylphenyl) propane, 2,2- Bis- (4-hydroxy-3-butylphenyl) propane, 2,2-bis- (4-hydroxy-3-isobutylphenyl) propane, 2,2-bis- (4-hydroxy-3-pentylphenyl) propane, 2,2-bis- (4-hydroxy-3-isopentylphenyl) propane, 2,2-bis- (4-hydroxy-3-neopentylpheny) Propane, 1,1-bis- (4-hydroxy-3-methylphenyl) butane, 1,1-bis- (4-hydroxy-2-methylphenyl) butane, 1,1-bis- (4-hydroxy) -3-ethylphenyl) butane, 1,1-bis- (4-hydroxy-3-propylphenyl) butane, 1,1-bis- (4-hydroxy-3-isopropylphenyl) butane, 1,1-bis- (4-hydroxy-3-butylphenyl) butane, 1,1-bis- (4-hydroxy-3-isobutylphenyl) butane, 1,1-bis- (4-hydroxy-3-pentylphenyl) butane, 1, 1-bis- (4-hydroxy-3-isopentylphenyl) butane, 1,1-bis- (4-hydroxy-3-neopentylphenyl) butane,

  2,2-bis- (4-hydroxy-3-methylphenyl) butane, 2,2-bis- (4-hydroxy-2-methylphenyl) butane, 2,2-bis- (4-hydroxy-3-ethyl) Phenyl) butane, 2,2-bis- (4-hydroxy-3-propylphenyl) butane, 2,2-bis- (4-hydroxy-3-isopropylphenyl) butane, 2,2-bis- (4-hydroxy) -3-butylphenyl) butane, 2,2-bis- (4-hydroxy-3-isobutylphenyl) butane, 2,2-bis- (4-hydroxy-3-pentylphenyl) butane, 2,2-bis- (4-hydroxy-3-isopentylphenyl) butane, 2,2-bis- (4-hydroxy-3-neopentylphenyl) butane, 1,1-bis- (4-hydroxy-3-methyl) Phenyl) pentane, 1,1-bis- (4-hydroxy-2-methylphenyl) pentane, 1,1-bis- (4-hydroxy-3-ethylphenyl) pentane, 1,1-bis- (4-hydroxy) -3-propylphenyl) pentane, 1,1-bis- (4-hydroxy-3-isopropylphenyl) pentane, 1,1-bis- (4-hydroxy-3-butylphenyl) pentane, 1,1-bis- (4-hydroxy-3-isobutylphenyl) pentane, 1,1-bis- (4-hydroxy-3-pentylphenyl) pentane, 1,1-bis- (4-hydroxy-3-isopentylphenyl) pentane, , 1-bis- (4-hydroxy-3-neopentylphenyl) pentane, 2,2-bis- (4-hydroxy-3-methylphenyl) pentane 2,2-bis- (4-hydroxy-2-methylphenyl) pentane, 2,2-bis- (4-hydroxy-3-ethylphenyl) pentane, 2,2-bis- (4-hydroxy-3-propyl) Phenyl) pentane, 2,2-bis- (4-hydroxy-3-isopropylphenyl) pentane, 2,2-bis- (4-hydroxy-3-butylphenyl) pentane, 2,2-bis- (4-hydroxy) -3-isobutylphenyl) pentane, 2,2-bis- (4-hydroxy-3-pentylphenyl) pentane, 2,2-bis- (4-hydroxy-3-isopentylphenyl) pentane, 2,2-bis -(4-hydroxy-3-neopentylphenyl) pentane, 3,3-bis- (4-hydroxy-3-methylphenyl) pentane, 3,3-bis- (4- Hydroxy-2-methylphenyl) pentane, 3,3-bis- (4-hydroxy-3-propylphenyl) pentane, 3,3-bis- (4-hydroxy-3-isopropylphenyl) pentane, 3,3-bis -(4-hydroxy-3-butylphenyl) pentane, 3,3-bis- (4-hydroxy-3-isobutylphenyl) pentane, 3,3-bis- (4-hydroxy-3-pentylphenyl) pentane, 3 , 3-bis- (4-hydroxy-3-isopentylphenyl) pentane, 3,3-bis- (4-hydroxy-3-neopentylphenyl) pentane, and the like.

  Among these, from the viewpoint of mechanical properties, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane, 1,1-bis- (4-hydroxy-3-ethylphenyl) ethane, 1, 1-bis- (4-hydroxy-3-isopropylphenyl) ethane, 1,1-bis- (4-hydroxy-3-sec-butylphenyl) ethane, 1,1-bis- (4-hydroxy-3-methyl) Phenyl) propane, 1,1-bis- (4-hydroxy-3-ethylphenyl) propane, 1,1-bis- (4-hydroxy-3-isopropylphenyl) propane, 1,1-bis- (4-hydroxy) -3-sec-butylphenyl) propane is preferred. Furthermore, among these, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane is particularly preferable.

In addition, although these structural units may be used individually by 1 type, they can also be used combining 2 or more types by arbitrary ratios by a desired physical property.
On the other hand, examples of the polyester resin that can be used as the second resin include those having a structural unit derived from a polybasic acid component and a polyhydric alcohol component. Examples of the polybasic acid component of the polyester resin include unsaturated acids such as maleic anhydride; aromatic saturated acids such as phthalic anhydride, terephthalic acid, and isophthalic acid; hexahydrophthalic anhydride, succinic acid, azelaic acid, and the like. Examples include aliphatic saturated acids.

  Moreover, a polyhydric alcohol or a polyhydric phenol is mentioned as a polyhydric alcohol component. Examples of these polyhydric alcohols or polyhydric phenols include aromatic diols and aliphatic dihydroxy compounds, and bifunctional phenolic compounds are preferably used. As the bifunctional phenol compound, the bifunctional phenol compound specifically exemplified in the polycarbonate resin that can be used as the second resin can be used. Among them, bis- (4-hydroxy-) is preferable. 3-methylphenyl) methane, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane, 1,1-bis- (4-hydroxy-3-methylphenyl) propane. More preferable examples include bis- (4-hydroxy-3-methylphenyl) methane and 1,1-bis- (4-hydroxy-3-methylphenyl) ethane. From the viewpoint of wear resistance and surface characteristics. Particularly preferred is 1,1-bis- (4-hydroxy-3-methylphenyl) ethane.

  Examples of the aliphatic dihydroxy compound include ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-pentanediol, pentamethylenediol, 2,4-pentanediol, 1,5-hexanediol, hexa Examples include methylene glycol, 1,5-heptanediol, heptamethylenediol, octamethylenediol, 1,9-nonanediol, 1,10-decamethyleneglycol, 1,2-cyclohexanediol, and preferably ethylene glycol , Propylene glycol, and 1,4-butanediol.

In addition, although these structural units may be used individually by 1 type, 2 or more types can also be used in arbitrary combinations and ratios by a desired physical property.
As described above, as the second resin, at least one resin selected from the group consisting of a polyester resin and a polycarbonate resin may be used as long as it includes a repeating structure represented by the formula (2). Among these, it is preferable to use a polycarbonate resin. That is, it is preferable to use a polycarbonate resin as at least a part of the second resin, and it is preferable to use a polycarbonate resin as the whole of the second resin.

  Moreover, it is preferable that the repeating structure represented by Formula (2) which 2nd resin contains is a structure represented by following formula (3).

  The second resin is preferably a polycarbonate resin, and is preferably a resin including a repeating structure represented by the formula (2). Furthermore, the second resin is a polycarbonate resin, and the formula (2 ) Is preferably a structure represented by Formula (3). When the second resin is a polycarbonate resin and the repeating structure represented by the formula (2) is a structure represented by the formula (3), the following formula (3) is contained in the polycarbonate. The ratio (component ratio) of the repeating units represented is usually 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more. The upper limit is ideally 100% by weight, and it is particularly preferable to use a polycarbonate resin whose repeating unit is composed only of the formula (3) as the second resin. This is because excellent wear resistance can be obtained.

  The viscosity average molecular weight of the second resin is arbitrary as long as the effects of the present invention are not significantly impaired, but if it is too low, the mechanical strength is insufficient, and is usually 10,000 or more, preferably 20,000 or more. Is over 30,000. In addition, if the viscosity average molecular weight is too high, the viscosity of the coating solution for forming the photosensitive layer may be increased and the productivity may be lowered. Therefore, it is usually 150,000 or less, preferably 100,000 or less, particularly 50,000 or less is preferable.

[I-1-3. Usage ratio]
There is no restriction | limiting in the usage-ratio of 1st resin and 2nd resin, as long as the effect of this invention is acquired, it is arbitrary. However, from the viewpoint of the durability of the photoreceptor, the amount of the second resin relative to the total weight of the first resin and the second resin is usually 80% by weight or less, preferably as the amount contained in the photosensitive layer. Is 70% by weight or less, more preferably 50% by weight or less. The lower limit is not particularly limited, but is usually 1% by weight or more, preferably 5% by weight or more. If the lower limit of this range is not reached, the wear resistance may be deteriorated, and if it exceeds the upper limit, the wear resistance may be deteriorated.
In addition, said range specification of the usage-ratio of 1st resin and 2nd resin is the weight range in the layer containing both 1st resin and 2nd resin. Therefore, when the photosensitive layer is composed of two or more layers, and there is a layer containing only one of the first resin and the second resin in those layers, only the one resin is used. The weights of the first resin and the second resin contained in the contained layer are not included in the calculation of the range definition.

[I-1-4. Other resins]
Furthermore, in the photosensitive layer of the photoreceptor of the present invention, a resin (combination resin) other than the first resin and the second resin may be used in combination as the binder resin. Examples of other resins used in combination here include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, polycarbonate, polyester, polyester polycarbonate, polysulfone, phenoxy, epoxy, silicone resin, and the like. And other thermoplastic resins and various thermosetting resins. Of these resins, polycarbonate resins and polyester resins are preferred. Moreover, these other resin used together may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

Furthermore, when using the combination resin, the first resin, the second resin, and the combination resin may be mixed and used, or may be used separately for each layer constituting the photosensitive layer. For example, the first resin and the second resin may be used as one binder resin for the charge generation layer and the charge transport layer, which will be described later, and the combination resin may be used as the other binder resin for the charge generation layer and the charge transport layer. Good.
Moreover, when using combined use resin, the usage-ratio of combined use resin is not specifically limited, It is arbitrary. For example, when the combination resin is used in a layer different from the layer using the first resin and the second resin, the amount of the combination resin used is not limited. However, when the first resin, the second resin, and the combination resin are used in the same layer (photosensitive layer, charge generation layer, charge transport layer), in order to obtain the effects of the present invention sufficiently, It is preferable to use together in the range which does not exceed the ratio of 1 resin, and it is preferable not to use these other resin together especially.

[I-2. Conductive support]
The electrophotographic photoreceptor of the present invention has at least a photosensitive layer on a conductive support. Although there is no restriction | limiting in particular in an electroconductive support body, For example, metal materials, such as aluminum, aluminum alloy, stainless steel, copper, and nickel; Conductive powders, such as a metal, carbon, and a tin oxide, were mixed and the electroconductivity was provided. Resin material: Resin, glass, paper, or the like, on which a conductive material such as aluminum, nickel, or ITO (indium-tin oxide) is vapor-deposited or applied on the surface thereof, is mainly used. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

Further, as the form of the conductive support, for example, a drum shape, a sheet shape, a belt shape or the like is used. Further, a conductive material having an appropriate resistance value may be coated on a conductive support made of a metal material in order to control conductivity, surface properties, etc., or to cover defects.
Further, when a metal material such as an aluminum alloy is used as the conductive support, it may be used after being subjected to anodizing treatment, chemical conversion coating treatment, or the like. When the anodizing treatment is performed, it is desirable to perform a sealing treatment by a known method.
The 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 conductive support.

[I-3. 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, a resin in which particles such as metal oxide (usually inorganic particles) are dispersed, or the like is used.
Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. 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 silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. A thing of a several crystalline state may be contained.

In addition, various particle sizes of the metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle size is usually 1 nm or more, preferably 10 nm or more, and usually 100 nm. Below, preferably 50 nm or less.
The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. Examples of the binder resin used for the undercoat layer include phenoxy, epoxy, polyvinyl pyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, and the like. Among these, alcohol-soluble copolymerized polyamide, modified polyamide, and the like are preferable because they exhibit good dispersibility and coating properties. In addition, the binder resin of an undercoat layer may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios. Further, the binder resin can be used only in the binder resin or in a form cured with a curing agent.

In addition, the use ratio of the particles with respect to the binder resin can be arbitrarily selected, but it is usually preferable in the range of 10% by weight to 500% by weight from the viewpoint of the stability of the dispersion and the coating property.
Further, the film thickness of the undercoat layer can be arbitrarily selected, but it is usually preferably from 0.1 μm to 25 μm from the viewpoint of photoreceptor characteristics and applicability. The undercoat layer may contain a known antioxidant or the like.

[I-4. Photosensitive layer]
The photosensitive layer of the electrophotographic photosensitive member is provided on the conductive support, and when it has an undercoat layer, it is provided on the undercoat layer (that is, on the conductive support through the undercoat layer).
The type of the photosensitive layer is usually a type (single layer type or dispersed type) photosensitive layer in which the charge generation material and the charge transport material are present in the same layer and dispersed or dissolved in the binder resin; A mold (laminated layer) in which a functional material is separated into two parts: a charge generation layer in which a generation material is dispersed or dissolved in a binder resin, and a charge transport layer in which a charge transport material is dispersed or dissolved in a binder resin. Type or function separation type) photosensitive layer. A photoreceptor having a single layer type photosensitive layer is a so-called single layer type photoreceptor, and a photoreceptor having a laminated type photosensitive layer is a so-called laminated type photoreceptor (or a function separation type photoreceptor). Any photosensitive layer may be used. Further, an overcoat layer (protective layer) may be provided on the photosensitive layer for the purpose of improving the chargeability and improving the wear resistance.

Further, as the laminated photosensitive layer, a charge generating 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. Among these, a forward laminated photosensitive layer that can exhibit the most balanced photoconductivity is preferable.
However, in the photoreceptor of the present invention, the photosensitive layer contains the first resin and the second resin. These first resin and second resin usually function as a binder resin in the photosensitive layer.

  Specifically, when the photosensitive layer is composed of one layer, the photosensitive layer itself contains the first resin and the second resin. Further, when the photosensitive layer is composed of two or more layers as in a laminated type, it is sufficient that the first resin and the second resin are contained in at least one of the layers constituting the photosensitive layer. That is, the photosensitive layer only needs to have at least one layer containing the first resin and the second resin. However, the layer containing the first resin and the second resin is preferably the outermost layer.

<Charge generation layer>
When the photoreceptor of the present invention is a laminated photosensitive layer, examples of the charge generation material used in the charge generation layer include selenium and its alloys, cadmium sulfide, and other inorganic photoconductive materials; phthalocyanine pigments, azo pigments Various photoconductive materials such as organic pigments such as quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments can be used. Among these, organic pigments are particularly preferable, and phthalocyanine pigments and azo pigments are more preferable.

  In particular, when a phthalocyanine compound is used as the charge generation material, specifically, a metal such as metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or an oxide or halide thereof. Coordinated phthalocyanines are used. Examples of the ligand to the trivalent or higher metal atom include a hydroxyl group and an alkoxy group in addition to the oxygen atom and chlorine atom shown above. Among them, particularly sensitive X-type, τ-type metal-free phthalocyanine, A-type, B-type, and D-type titanyl phthalocyanine, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, and the like are preferable.

  Of the crystal forms of titanyl phthalocyanine mentioned here, A type and B type are described in W.W. It has been shown by Heller et al. As phase I and phase II, respectively (Zeit. Kristallogr. 159 (1982) 173), and type A is known as a stable type. The D-type is a crystal type characterized by a clear peak at a diffraction angle 2θ ± 0.2 ° of 27.3 ° in powder X-ray diffraction using CuKα rays.

  On the other hand, when an azo pigment is used as the charge generating substance, examples thereof include bisazo pigments, trisazo pigments, and tetrakis azo pigments. Among these, those having a plurality of azo groups are preferable, and bisazo pigments and trisazo pigments are particularly preferable. Among these, specific examples of particularly suitable azo pigments are shown below.

さらに、アゾ顔料の中でも、下記式で表される化合物が特に好ましい。

Furthermore, among the azo pigments, a compound represented by the following formula is particularly preferable.

(In the formula, R represents an alkyl group having a total carbon number of 4 to 20 having a cycloalkyl group optionally having an alkyl substituent.)
Further, the charge generation materials may be used alone or in combination of two or more in any combination and ratio. Further, when two or more charge generation materials are used in combination, the charge generation materials to be used together and the mixed state in the crystal state may be used by mixing the respective constituent elements later, synthesis, pigmentation Alternatively, a mixed state may be generated and used in a charge generation material manufacturing / processing step such as crystallization. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known.

  Further, these charge generation materials form a charge generation layer in a state of being bound by a binder resin. At this time, as the resin for the charge generation layer, for example, polyester resin, polyvinyl acetate, polyacrylate ester, polymethacrylate ester, polyester, polycarbonate, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin Various binder resins such as urethane resin, cellulose ester, and cellulose ether can be used. Moreover, you may use said 1st resin and 2nd resin as binder resin of an electric charge generation layer. Moreover, binder resin may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, the ratio between the charge generation material and the binder resin in the charge generation layer is arbitrary as long as the effects of the present invention are not significantly impaired. However, the amount of the charge generation material in the charge generation layer is usually 30 parts by weight or more, preferably 50 parts by weight or more, more preferably 100 parts by weight or more, and usually 500 parts by weight or less with respect to 100 parts by weight of the binder resin. Preferably, it is 400 parts by weight or less, more preferably 300 parts by weight or less. If the amount of the charge generating material is too small, sufficient sensitivity may not be obtained. If the amount is too large, the photoreceptor may be deteriorated in chargeability and sensitivity.

The thickness of the charge generation layer is not limited, but is usually 0.1 μm or more, preferably 0.15 μm or more, and usually 1 μm or less, preferably 0.6 μm or less.
The charge generation layer has well-known plasticizers, antioxidants, ultraviolet rays for improving the film formability, flexibility, coatability, stain resistance, gas resistance, light resistance, mechanical strength, etc. You may contain additives, such as an absorber, an electron-withdrawing compound, dye, and a pigment. Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of dyes and pigments include various pigment compounds and azo compounds. Residual potential inhibitors for suppressing residual potential, dispersion aids for improving dispersion stability, leveling agents (for example, silicone oil, fluorine-based oil, etc.) for improving coating properties, surfactants Etc. can also be used as additives. In addition, an additive may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

<Charge transport layer>
The charge transport layer of the multilayer photosensitive layer contains a charge transport material, 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).

  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, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable. Any one of these charge transport materials may be used alone, or two or more thereof may be used in any combination and ratio.

  As the binder resin used for the charge transport layer, any resin can be used as long as it is known to be usable for the charge transport layer of the electrophotographic photoreceptor. However, preferably, the first resin and the second resin are used. As described above, when the photosensitive layer is a laminated type, it is usually preferable that the charge transport layer contains the first resin and the second resin. As described above, other resins (combined resins) may be used in combination with the first resin and the second resin.

Furthermore, the charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different components or composition ratios. When the photosensitive layer is composed of two or more layers, it is preferable that one or more of the layers further include the first resin and the second resin.
When the charge generation layer contains the first resin and the second resin, a resin other than the first resin and the second resin may be used as the binder resin for the charge transport layer.

  Furthermore, in the charge transport layer, the ratio between the charge transport material and the binder resin is arbitrary as long as the effects of the present invention are not significantly impaired. However, the amount of the charge transport material in the charge transport layer is usually 20 parts by weight or more with respect to 100 parts by weight of the binder resin. Among these, 30 parts by weight or more is preferable from the viewpoint of residual potential reduction, and 40 parts by weight or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. Among these, 50 parts by weight or more is particularly preferable. Further, it is usually 200 parts by weight or less, and is preferably used at a ratio of 150 parts by weight or less from the viewpoint of thermal stability of the photosensitive layer. Among them, 110 parts by weight or less is more preferable from the viewpoint of compatibility between the charge transport material and the binder resin, 100 parts by weight or less is more preferable, 80 parts by weight or less is particularly preferable from the viewpoint of printing durability, and from the viewpoint of scratch resistance. 70 parts by weight or less is particularly preferable. On the other hand, if the amount of the charge transport material is too small, the electrical characteristics may be deteriorated. If the amount is too large, the coating film becomes brittle and the wear resistance may be deteriorated.

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. Further, the range is 30 μm or less.
In addition, the charge transport layer may contain an additive in order to improve the film formability, flexibility, coatability, stain resistance, gas resistance, light resistance and the like, similar to the charge generation layer. . As an example of an additive, the thing similar to what was illustrated as an additive contained in a charge generation layer is mentioned. At this time, also in the charge transport layer, one type of additive may be used alone, or two or more types may be used in any combination and ratio.

Furthermore, the charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different components or composition ratios.
<Dispersion type (single layer type) photosensitive layer>
The dispersion-type photosensitive layer is configured by dispersing the above-described charge generation material in the charge transport layer having the above-described mixing ratio. Therefore, in the dispersion type photosensitive layer, the types of the charge transporting material and the binder resin and the usage ratio thereof are explained for the charge transporting layer of the laminated type photosensitive layer in the case of containing the first resin and the second resin. It is the same as what I did. Therefore, the dispersion type photosensitive layer contains the first resin and the second resin as the binder resin.

Further, it is desirable that the particle size of the charge generating material in the dispersion type photosensitive layer is sufficiently small. Specifically, it is usually used at 1 μm or less, preferably 0.5 μm or less.
Furthermore, if the amount of the charge generating material dispersed in the dispersion type photosensitive layer is too small, sufficient sensitivity cannot be obtained, and if it is too large, there are problems such as a decrease in chargeability and a decrease in sensitivity. Therefore, the amount of the charge generating substance in the dispersion type photosensitive layer is usually 0.5% by weight or more, preferably 1% by weight or more, and usually 50% by weight or less, preferably 20% by weight or less.
The thickness of the dispersion type photosensitive layer is arbitrary, but is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less, preferably 45 μm or less.
Further, the dispersion type photosensitive layer may contain an additive in the same manner as the charge generation layer.

<Other layers>
In addition to the undercoat layer, the charge generation layer, the charge transport layer, and the single-layer type photosensitive layer, the photosensitive member may further include other layers.
For example, a protective layer may be provided on the photosensitive layer for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to discharge products generated from a charger or the like. In addition, the outermost surface layer may contain, for example, a fluororesin, a silicone resin, etc. for the purpose of reducing frictional resistance and wear on the surface of the photoreceptor, and further, particles and inorganic compounds made of these resins. Particles may be included.

<Method for forming each layer>
There are no limitations on the method of forming each layer such as the undercoat layer, the photosensitive layer (charge generation layer, charge transport layer, single-layer type photosensitive layer), protective layer and the like. For example, a known method of applying a coating solution obtained by dissolving or dispersing a substance to be contained in a layer to be formed in a solvent directly on a conductive support or through another layer is applied. it can.
Therefore, for example, in the case of forming a charge generation layer, a coating liquid containing a charge generation material, a binder resin, and, if necessary, a solvent, an additive, etc. is prepared, and the coating liquid is used as a conductive support. Directly or via another layer (on a conductive support in the case of a forward laminate type photosensitive layer (on an undercoat layer if an undercoat layer is provided), or a reverse laminate type photosensitive layer) In this case, it may be applied on the charge generation layer). Thereafter, the charge generation layer can be formed by removing the solvent by drying.

  For example, when forming a charge transport layer, a coating liquid containing a charge transport material and a binder resin and, if necessary, a solvent, an additive and the like is prepared, and the coating liquid is used as a conductive support. Directly or through another layer (on a charge generation layer in the case of a forward lamination type photosensitive layer, or on a conductive support in the case of a reverse lamination type photosensitive layer) If provided, it may be applied on the undercoat layer)). Thereafter, the charge transport layer can be formed by removing the solvent by drying.

  For example, when forming a single-layer type photosensitive layer, a coating solution containing a charge generating material, a charge transporting material, a binder resin, and, if necessary, a solvent, an additive, etc. is prepared, and the coating solution Is coated on the conductive support directly or via another layer (or on the undercoat layer when an undercoat layer is provided). Thereafter, the solvent is removed by drying, whereby a single-layer type photosensitive layer can be formed.

  In this case, the coating method is arbitrary, and for example, a dip coating method, a spray coating method, a nozzle coating method, a bar coating method, a roll coating method, a brate coating method, or the like can be used. Among these, the dip coating method is preferable because of its high productivity. Note that these coating methods may be performed by only one method, or may be performed by combining two or more methods.

  There are no particular limitations on the solvent used for preparing the coating solution, that is, the solvent or the dispersion medium, but specific examples include alcohols such as methanol, ethanol, propanol, and 2-methoxyethanol; tetrahydrofuran, 1,4-dioxane, Ethers such as dimethoxyethane; esters such as methyl formate and ethyl acetate; ketones such as acetone, methyl ethyl ketone, cyclohexanone and 4-methoxy-4-methyl-2-pentanone; aromatic hydrocarbons such as benzene, toluene and xylene : Chlorinated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene; n-butylamine , Isopropanol Emissions, 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.

  In addition, the amount of solvent used is not particularly limited, but considering the purpose of each layer and the properties of the selected solvent, it may be appropriately adjusted so that the physical properties such as the solid content concentration and viscosity of the coating solution are within a desired range. preferable. As a specific range, the following is preferable. That is, when the coating solution is used for forming a photosensitive layer of a single layer type photoreceptor or a charge transport layer of a laminated type photoreceptor, the solid content concentration of the coating solution is usually 10% by weight or more, preferably 15% by weight or more. In addition, it is desirable to adjust the amount of the solvent used so that it is usually 40% by weight or less, preferably 35% by weight or less. Further, in order to keep the coating property of the coating solution good, the viscosity of the coating solution is usually in the range of 50 mPa · s or more, preferably 100 mPa · s or more, and usually 1000 mPa · s or less, preferably 600 mPa · s or less. It is desirable to adjust the composition and amount of the solvent so that

Further, when the coating solution is used for forming the charge generation layer of the multilayer photoreceptor, the solid content concentration of the coating solution is usually 1% by weight or more, preferably 2% by weight or more, and usually 15% by weight or less. It is desirable to adjust the amount of solvent used so that it is preferably in the range of 10% by weight or less. Further, in order to keep the coating property of the coating solution good, the viscosity of the coating solution is usually 0.1 mPa · s or more, preferably 0.5 mPa · s or more, and usually 10 mPa · s or less, preferably 8 mPa · s. It is desirable to adjust the composition and use amount of the solvent so that it is in the range of s or less.

  The binder resin according to the present invention is preferable because it has excellent solubility in the solvent used in the coating step and also has excellent stability of the coating solution after dissolution. For example, it is usually possible to obtain the advantages that the coating liquid for forming the photosensitive layer can prevent the binder resin from being precipitated and suppress the cloudiness of the coating liquid. The reason why such an advantage can be obtained is not clear, but is presumed to be due to the chemical structure specific to the binder resin according to the present invention.

  In particular, the coating solution is very useful in that the electrical characteristics are stable over time. That is, a new coating solution immediately after the manufacture or an old coating solution after a lapse of time is usually preferable because a photoreceptor having suitable electrical characteristics can be manufactured (maintained). Specifically, the coating solution is unlikely to change in liquid state due to generation of precipitates and gels, change in the viscosity of the liquid, and the like over time. The liquidity of the coating liquid can be confirmed by visual observation because the liquid becomes cloudy when precipitates or the like are generated, and can be said to be stable over time when no cloudiness is generated. Further, when the change in viscosity is measured and the change in viscosity is small (for example, when the rate of change in viscosity after 3 months is 10% or less), it can be said that the change is stable over time.

  By the way, in the photoconductor of the present invention, when an image is formed, an electrostatic latent image is formed by performing exposure with writing light from an exposure unit. The writing light used at this time is arbitrary as long as an electrostatic latent image can be formed. Among them, monochromatic light having an exposure wavelength of usually 380 nm or more, particularly 400 nm or more, and usually 500 nm or less, particularly 480 nm or less. It is preferable to use it. Thereby, a photoconductor excellent in wear resistance can be exposed with light having a smaller spot size, and a high-quality image having high resolution and high gradation can be formed.

[II. 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 photoreceptor 1, a charging device (charging means) 2, an exposure device (exposure means; image exposure means) 3, and a developing device (developing means) 4. Furthermore, a transfer device (transfer means) 5, a cleaning device (cleaning means) 6, and a fixing device (fixing means) 7 are provided as necessary.
The electrophotographic photosensitive member 1 is not particularly limited as long as it is the above-described electrophotographic photosensitive member, but in FIG. 1, as an example, a drum-shaped photosensitive member in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. Showing the body. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photoreceptor 1.

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

  The type of exposure apparatus 3 is not particularly limited as long as it can form an electrostatic latent image on the photosensitive surface of the electrophotographic photosensitive member 1 by performing exposure (image exposure) on the electrophotographic photosensitive member 1. Absent. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, and LEDs (light emitting diodes). Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure is performed using monochromatic light having a wavelength of 700 nm to 850 nm, monochromatic light having a wavelength of 600 nm to 700 nm, slightly short wavelength, or monochromatic light having a wavelength of 300 nm to 500 nm. Just do it.

  In particular, in the case of an electrophotographic photoreceptor using a phthalocyanine compound as a charge generating substance, it is preferable to use monochromatic light having a wavelength of 700 nm to 850 nm, and in the case of an electrophotographic photoreceptor using an azo compound, white light or wavelength It is preferable to use monochromatic light of 700 nm or less. In the photoreceptor according to the present invention, it is particularly preferable to use monochromatic light having a wavelength of 380 nm to 500 nm as a light source for light input.

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

The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicone 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 silicone resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such 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 weight / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

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

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

  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 (pressure roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. Each of the upper and lower fixing members 71 and 72 includes a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, and a fixing sheet. A member can be used. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

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

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

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

After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.
In addition to the above-described configuration, the image forming apparatus may be configured to perform, for example, a static elimination process. The neutralization step is a step of performing static elimination on 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.

Further, the image forming apparatus may be further modified and configured, for example, a configuration capable of performing processes such as a pre-exposure process and an auxiliary charging process, a structure performing offset printing, and a plurality of types. A full-color tandem system configuration using toner may be used.
The 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 (electrophotography). The electrophotographic photosensitive member cartridge may be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the charging device 2, the exposure device 3, the developing device 4, and the transfer device 5 can be integrally supported together with the photoreceptor 1 to form a cartridge. Also in this case, similarly to the cartridge described in the above embodiment, when the electrophotographic photosensitive member 1 and other members deteriorate, for example, the electrophotographic photosensitive member cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic image is obtained. By attaching the photosensitive cartridge to the image forming apparatus main body, maintenance and management of the image forming apparatus are facilitated.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the following examples are given in order to describe the present invention in detail, and the present invention is not limited to the examples shown below unless it is contrary to the gist thereof. In addition, the description of “parts” in the following examples and comparative examples indicates “parts by weight” unless otherwise specified.

<Measurement method of viscosity average molecular weight>
First, measurement of the viscosity average molecular weight of the resin will be described.
The resin to be measured is dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. Using a Ubbelohde capillary viscometer with a solvent (dichloromethane) flow time t0 of 136.16 seconds, the flow time t of the sample solution is measured in a constant temperature bath set at 20.0 ° C. The viscosity average molecular weight Mv is calculated according to the following formula.
a = 0.438 × ηsp + 1 ηsp = (t / t0) −1
b = 100 × ηsp / C C = 6.00
η = b / a
Mv = 3207 × η ^1.205

<Manufacture of resin>
Hereinafter, the manufacturing method of a polyester resin is demonstrated.
[Production Example 1 (Production of Resin X)]
In a 1000 mL beaker, 22.34 g of sodium hydroxide and 940 mL of H ₂ O were weighed and dissolved with stirring. To this, 51.04 g of 1,1-bis (4-hydroxy-3-methylphenyl) ethane was added, stirred and dissolved, and then the aqueous alkaline solution was transferred to a 2 L reaction vessel. Next, 0.5579 g of benzyltriethylammonium chloride and 1.0613 g of 2,3,5-trimethylphenol were sequentially added to the reaction vessel.

  Separately, a mixed solution of 63.37 g of diphenyl ether-4,4′-dicarboxylic acid chloride and 470 mL of dichloromethane was transferred into the dropping funnel. While maintaining the external temperature of the polymerization tank at 20 ° C. and stirring the alkaline aqueous solution in the reaction tank, the mixed solution was dropped from the dropping funnel over 1 hour. After further stirring for 5 hours, 783 mL of dichloromethane was added and stirring was continued for 7 hours.

Thereafter, 8.10 mL of acetic acid was added and stirred for 30 minutes, then stirring was stopped and the organic layer was separated. This organic layer was washed twice with 942 mL of 0.1N aqueous sodium hydroxide solution, then washed twice with 942 mL of 0.1N hydrochloric acid, and further washed twice with 942 mL of H ₂ O. The washed organic layer was poured into 6266 mL of methanol, and the resulting precipitate was removed by filtration and dried to obtain the target resin X (first resin). It was 51,700 when the viscosity average molecular weight of the obtained resin X was measured by said measuring method. The repeating structure of Resin X 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 weight of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were flowed at high speed. The surface-treated titanium oxide obtained by mixing in a high-speed mixing kneader (“SMG300” manufactured by Kawata Co., Ltd.) and mixing at high speed at a rotational peripheral speed of 34.5 m / sec has a weight ratio of methanol / 1-propanol. A dispersion slurry of hydrophobized titanium oxide was obtained by dispersing with a ball mill in a 7/3 mixed solvent. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (described in Examples of JP-A-4-31870) 4-amino-3-methylcyclohexyl) methane [compound represented by the following formula (B)] / hexamethylenediamine [compound represented by the following formula (C)] / decamethylene dicarboxylic acid [represented by the following formula (D) Compound] / octadecamethylene dicarboxylic acid [compound represented by the following formula (E)] is heated to a copolyamide pellet having a composition molar ratio of 60% / 15% / 5% / 15% / 5%. While stirring and mixing, the polyamide pellets are dissolved, and then subjected to ultrasonic dispersion treatment to obtain methanol / 1-propanol / toluene. Weight ratio is 7/1/2, and hydrophobic treatment containing titanium oxide / copolymer polyamide in a weight ratio of 3/1, solid content concentration 18.0% undercoat layer dispersion.

The undercoat layer-forming coating solution thus obtained is applied onto a polyethylene terephthalate sheet with aluminum deposited on the surface with a wire bar so that the film thickness after drying is 1.2 μm, dried and subtracted. A layer was provided.
Next, in X-ray diffraction by CuKα ray, a Bragg angle (2θ ± 0.2) shows a strong diffraction peak at 27.3 °, and 10 parts by weight of oxytitanium phthalocyanine having a powder X-ray diffraction spectrum shown in FIG. In addition to 150 parts by weight of 2-dimethoxyethane, pulverization and dispersion treatment was performed with a sand grind mill to prepare a pigment dispersion. 160 parts by weight of the pigment dispersion thus obtained was added to 100 parts by weight of a 5% 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 weight.

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, 50 parts by weight of a charge transport material composed of a mixture of geometric isomers represented by the following structural formula (1), 75 parts by weight of the resin X produced in Production Example 1, and polycarbonate resin A (first No. 2 resin, viscosity average molecular weight 29,000) 25 parts by weight, silicone oil 0.05 parts by weight as a leveling agent, mixed with 640 parts by weight of a mixed solvent of tetrahydrofuran and toluene (tetrahydrofuran 80% by weight, toluene 20% by weight). Then, a coating solution for forming a charge transport layer was prepared.

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.
The photoreceptor sheet was evaluated for abrasion resistance by a Taber abrasion tester 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.
[Example 2]
A photoreceptor sheet was produced in the same manner as in Example 1 except that 50 parts by weight of the resin X used in the charge transport layer forming coating solution of Example 1 and 50 parts by weight of Resin A were used. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Example 3]
A photoreceptor sheet was prepared in the same manner as in Example 1 except that 25 parts by weight of the resin X used in the coating solution for forming the charge transport layer of Example 1 and 75 parts by weight of the resin A were used. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.

[Comparative Example 1]
A photoreceptor sheet was produced in the same manner as in Example 1 except that 100 parts by weight of the resin X used in the coating liquid for forming the charge transport layer of Example 1 was used and that the resin A was not used. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 2]
A photoreceptor sheet was produced in the same manner as in Example 1 except that the resin X used in the coating liquid for forming a charge transport layer in Example 1 was not used and the resin A was changed to 100 parts by weight. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 3]
The same procedure as in Example 1 was conducted except that the resin A used in the coating liquid for forming the charge transport layer in Example 1 was changed to the polycarbonate resin B (second resin, viscosity average molecular weight 30,200) having the following repeating structure. Thus, a photoreceptor sheet was prepared. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.

[Comparative Example 4]
A photoreceptor sheet was prepared in the same manner as in Example 2 except that the resin A used in the coating liquid for forming the charge transport layer in Example 2 was changed to polycarbonate resin B (second resin, viscosity average molecular weight 30,200). Produced. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 5]
A photosensitive sheet was prepared in the same manner as in Example 3 except that the resin A used in the charge transport layer forming coating solution of Example 3 was changed to polycarbonate resin B (second resin, viscosity average molecular weight 30,200). Produced. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 6]
A photosensitive sheet was prepared in the same manner as in Example 1 except that 100 parts by weight of the polycarbonate resin B was used instead of the resin X and the resin A used in the charge transport layer forming coating solution of Example 1. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 7]
The same procedure as in Example 1 was conducted except that the resin A used in the coating liquid for forming the charge transport layer in Example 1 was changed to the polycarbonate resin C (second resin, viscosity average molecular weight 40, 100) having the following repeating structure. Thus, a photoreceptor sheet was prepared. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.

[Comparative Example 8]
A photoreceptor sheet was prepared in the same manner as in Example 1 except that the resin A used in the charge transport layer forming coating solution of Example 2 was changed to polycarbonate resin C (second resin, viscosity average molecular weight 40, 100). Produced. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 9]
A photoreceptor sheet was prepared in the same manner as in Example 1 except that the resin A used in the coating solution for forming the charge transport layer in Example 3 was changed to polycarbonate resin C (second resin, viscosity average molecular weight 40, 100). Produced. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 10]
A photoreceptor sheet was produced in the same manner as in Example 1 except that 100 parts by weight of the polycarbonate resin C was used instead of the resin X and the resin A used in the charge transport layer forming coating solution of Example 1. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 11]
The same as Example 1 except that the resin A used in the coating liquid for forming the charge transport layer of Example 1 was changed to the polyarylate resin D (second resin, viscosity average molecular weight 32,000) having the following repeating structure. Thus, a photoreceptor sheet was produced. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.

[Comparative Example 12]
Photosensitive sheet as in Example 1 except that the resin A used in the charge transport layer forming coating solution of Example 2 was changed to polyarylate resin D (second resin, viscosity average molecular weight 32,000). Was made. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 13]
Photosensitive sheet in the same manner as in Example 1 except that the resin A used in the charge transport layer forming coating solution of Example 3 was changed to polyarylate resin D (second resin, viscosity average molecular weight 32,000). Was made. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 14]
A photoreceptor sheet was prepared in the same manner as in Example 1 except that 100 parts by weight of polyarylate resin D was used instead of using resin X and resin A used in the coating liquid for forming the charge transport layer in Example 1. . The same evaluation as in Example 1 was performed, and the results are shown in Table 1.

[Comparative Example 15]
Photosensitive sheet in the same manner as in Example 1 except that the resin X used in the coating liquid for forming the charge transport layer in Example 1 is polyarylate resin D (second resin, viscosity average molecular weight 32,000). Was made. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 16]
Photosensitive sheet in the same manner as in Example 1 except that the resin X used in the coating liquid for forming the charge transport layer in Example 2 is polyarylate resin D (second resin, viscosity average molecular weight 32,000). Was made. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
[Comparative Example 17]
Photosensitive sheet in the same manner as in Example 1 except that the resin X used in the coating liquid for forming the charge transport layer in Example 3 is polyarylate resin D (second resin, viscosity average molecular weight 32,000). Was made. The same evaluation as in Example 1 was performed, and the results are shown in Table 1.
<Abrasion test>
The photoreceptor sheets prepared in the above examples and comparative examples were each cut into a circle having a diameter of 10 cm and subjected to wear evaluation with a Taber abrasion tester (manufactured by Taber). Test conditions were measured by comparing the weight before and after the test with 1000 wheels without load (the weight of the wear wheel) under the atmosphere of 23 ° C. and 50% RH without load (self weight of the wear wheel). did. The results are shown in Table 1.

<Electrical characteristics evaluation>
The photoconductor sheets prepared in the above-described examples and comparative examples were mounted on a photoconductor characteristic tester (model EPA8100 manufactured by Kawaguchi Electric Co., Ltd.), and the photoconductor was negatively charged with a corona current of 35 μA in the dark. After (Vo), 780 nm light was continuously irradiated, and the half potential exposure (E1 / 2) required to reduce the surface potential from −700 V to −350 V and the residual potential when irradiated with 10 μJ / cm ^2. (Vr) was measured. The results are shown in Table 1.

  From the above results, the electrophotographic photosensitive member having a photosensitive layer containing the first resin (resin X) and the second resin (resin A) according to the present invention is shown in the results of the Taber test in Table 1. Thus, it can be seen that the wear amount is small and the wear resistance is excellent. In particular, paying attention to Example 1 and Example 2, it can be seen that the wear resistance is particularly good when the content of the second resin is 70% by weight or less in all the binder resins. Further, the wear amount is smaller than that of the electrophotographic photosensitive member having the photosensitive layer containing only the first resin (resin X) or the second resin (resin A), and the first resin (resin X) and the second resin It is understood that the wear resistance is improved by the effect of the combination of the resin (resin A). Furthermore, in order to obtain the effect of the present invention, the combination of the first resin and the second resin is important, and even if a combination of the first resin and the resin other than the second resin is applied, It is not possible to obtain an electrophotographic photosensitive member having particularly high wear resistance such as the electrophotographic photosensitive member of the present invention.

[Example 4]
As a charge generation substance, 150 parts by weight of 4-methyl-4-methoxy-pentanone-2 is added to 10 parts by weight of oxytitanium phthalocyanine having a powder X-ray diffraction spectrum by CuKα rays shown in FIG. After time pulverization and atomization treatment, 100 parts by weight of a 5 wt% 1,2-dimethoxyethane solution of polyvinyl butyral (“Decambutyral # 6000C” manufactured by Denki Kagaku Kogyo Co., Ltd.) as a binder resin and a phenoxy resin (Union Car) A coating solution for forming a charge generation layer was prepared by adding 100 parts by weight of a 5 wt% 1,2-dimethoxyethane solution of “PKHH” manufactured by Bite Corporation.

Next, the surface of a cylinder made of an aluminum alloy having a mirror-finished outer diameter of 30 mm, length of 285 mm, and wall thickness of 1.0 mm is anodized, and then sealed with a sealing agent containing nickel acetate as a component. By performing the hole treatment, an anodic oxide film (alumite film) of about 6 μm was formed. This cylinder was dip coated in the previously prepared coating solution for forming a charge generation layer to form a charge generation layer having a dried film thickness of about 0.3 μm.

  Next, 50 parts by weight of a charge transport material having the structure of Formula 1, 50 parts by weight of resin X, 50 parts by weight of polycarbonate resin A (second resin, viscosity average molecular weight 29,000), octadecyl-3- (3,5- 8 parts by weight of di-t-butyl-4-hydroxyphenyl) propionate (manufactured by Ciba Geigy: “Irganox 1076”), 0.05 part by weight of silicone oil as a leveling agent, and a mixed solvent of tetrahydrofuran and toluene (80 weight of tetrahydrofuran) %, Toluene 20 wt%) was mixed with 640 parts by weight to prepare a coating solution for forming a charge transport layer. The cylinder in which the charge generation layer was previously formed was dip coated in this charge transport layer forming coating solution to prepare a photosensitive drum provided with a charge transport layer having a thickness of 20 μm after drying.

When this photoconductor is mounted on a laser printer LP3000C manufactured by Seiko Epson Corporation and 6,000 text images each having a print area of 5% for black, magenta, yellow, and cyan are printed, the film thickness reduction of the photoconductor is 1. .1 μm. Also, after printing 6,000 sheets, a 1/8 pt line and a 0.1 mm dot were printed, both of which were good results.
Specification of LP3000C
・ 4 cycles
・ Color 5ppm, Monochrome 20ppm
・ 600 dpi
・ Scorotron charging
・ Semiconductor laser scanning
・ One-component developer, non-contact development

[Comparative Example 18]
A photosensitive drum was produced in the same manner as in Example 4 except that 100 parts by weight of the resin X used in the charge transport layer forming coating solution of Example 4 was used and that the resin A was not used. Similarly, when a film reduction test was performed, the film reduction of the photoreceptor was 1.2 μm. The line was 1/8 pt after printing 6,000 sheets, and the circularity (actual area / area of a circle having the same circumference) of 0.1 mm dot was observed.
[Comparative Example 19]
A photosensitive drum was produced in the same manner as in Example 4 except that the resin X used in the coating solution for forming the charge transport layer in Example 4 was not used and the resin A was 100 parts by weight. Similarly, when the film reduction test was performed, the film reduction of the photoreceptor was 1.9 μm. After printing 6,000 sheets, a 1/8 pt line and a 0.1 mm dot were printed.
The photoreceptor of this example is excellent in that it exhibits excellent wear resistance and a good image can be obtained.

[Example 5]
The surface of a cylinder made of an aluminum alloy having a mirror-finished outer diameter of 30 mm, length of 375.8 mm, and wall thickness of 1.0 mm is anodized and then sealed with a sealant mainly composed of nickel acetate. By performing the hole treatment, an anodic oxide coating (alumite coating) of about 6 μm was formed.

Further, 300 parts of 1,2-dimethoxyethane was added to 15 parts of the charge generation material having the following structure as a charge generation material, and the mixture was pulverized for 8 hours by a sand grind mill and subjected to atomization dispersion treatment. Subsequently, 7.5 parts of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Denkabutyral” # 6000C), 7.5 parts of phenoxy resin (product of Union Carbide, PKHH) 7.5
Part with a binder solution dissolved in 285 parts 1,2-dimethoxyethane,
A mixed liquid of 63 parts by weight of 2-dimethoxyethane and 72 parts by weight of 4-methoxy-4-methyl-2-pentanone was added to prepare an azo pigment dispersion having a solid content (pigment + resin) concentration of 4.0% by weight. .

（Ｚは

の混合物を表す。）

(Z is

Represents a mixture of )

This azo pigment dispersion and the charge generation layer forming dispersion prepared in Example 1 were mixed at a weight ratio of 1: 1 to prepare a charge generation layer forming coating solution containing both the azo pigment and titanyl phthalocyanine. .
An anodized aluminum cylinder was dip-coated in this coating solution, and a charge generation layer was prepared so that the film thickness after drying was 0.6 μm.

  Next, 35 parts each of compounds (E) and (F) having the following structure as charge transport materials, a total of 70 parts,

75 parts of polyester resin X produced in Production Example 1 as a binder resin, 25 parts by weight of polycarbonate resin A, and 0.05 part of silicone oil (trade name KF96 Shin-Etsu Chemical Co., Ltd.) as a leveling agent, tetrahydrofuran / toluene (8/2) Mixing with 640 parts of a mixed solvent, a coating solution for forming a charge transport layer was prepared.
This coating solution was dip-coated on the above-described charge generation layer so that the film thickness after drying was 18 μm to form a charge transport layer, thereby obtaining a photosensitive drum having a laminated photosensitive layer.

[Comparative Example 20]
A charge transport layer forming coating solution was prepared in the same manner as in Example 5 except that the resin X used in the charge transport layer forming coating solution of Example 5 was changed to polyester resin D. Using this coating solution, a photoreceptor drum was obtained in the same manner as in Example 5.
[Evaluation]
The electrophotographic photosensitive member obtained above was subjected to the following electrical property test and actual machine evaluation. These results are summarized in Table 3.

<Electrical characteristics test>
Attached to an electrophotographic characteristic evaluation device (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, page 404-405) prepared according to the standard of the Electrophotographic Society, charging, exposure, The electrical characteristics were evaluated by the cycle of potential measurement and static elimination.
The photosensitive member is charged so that the initial surface potential is −700 V, and the halogen lamp light is irradiated with a monochromatic light of 405 nm using an interference filter, and the irradiation energy (μJ / cm ² ) was defined as sensitivity E1. Further, the surface potential after exposure (−V) when exposed at 2.0 μJ / cm ² was defined as VL1.

Similarly, the sensitivity E2 and the post-exposure surface potential VL2 were measured in exactly the same procedure using a single-color light of 760 nm using an interference filter.
When measuring VL1 and VL2, the time required from the exposure to the potential measurement was 200 ms. The measurement environment was a temperature of 25 ° C. and a relative humidity of 50%.
The photoconductor of Example 5 sufficiently transmits 405 nm light, whereas the photoconductor of Comparative Example 20 has a significantly reduced sensitivity because the charge transport layer absorbs light of 405 nm.

<Evaluation of actual machine>
The produced photosensitive drum was mounted on a black drum cartridge of a commercially available tandem type color printer (Microline Pro 9800PS-E manufactured by Oki Data Co., Ltd.) compatible with A3 printing, and mounted on the printer.
Specifications of MICROLINE Pro 9800PS-E
・ Quadruple tandem
・ Color 36ppm, Monochrome 40ppm
・ 1200 dpi
・ DC contact roller charging
・ Writing by LED
・ With static elimination light
・ Polymerized toner
Next, a personal computer was connected to this printer, a gray scale (halftone) image was input, and the density of the output image was confirmed. Even when the photosensitive drum of either Example 5 or Comparative Example 20 was used, A good density image was obtained.

Next, the exposure part of the printer was modified so that light from a small spot irradiation type blue LED (B3MP-8: 470 nm) manufactured by Nisshin Denshi was able to be irradiated onto the photoreceptor.
When a black drum cartridge equipped with the photosensitive drum of Example 5 was attached to this modified device and a line was drawn, a good image was obtained. Further, when a strobe illumination power source LPS-203KS was connected to the small spot irradiation type blue LED and a point was drawn, a point image having a radius of 8 mm could be obtained.

From the results of the above-mentioned actual machine evaluation and electrical property test, the photoreceptor of Example 5 exhibits sufficient electrical properties even in the purple to blue exposure (405 nm), so even if it is exposed with a blue LED near 400 nm, an equivalent image is obtained. However, it is presumed that it is difficult to obtain a good image with the photoconductor of Comparative Example 20.
Next, 30,000 images of a text document having a printing area of about 5% were formed under conditions of a temperature of 25 ° C. and a humidity of 50%. At this time, the relative value of the average film reduction amount (reduced film thickness of the photoconductor of the example / reduced film thickness of the photoconductor of the comparative example) was 0.51, and the photoconductor of the example showed excellent wear resistance. It was. This effect is presumed to be the same for purple to blue exposure.

  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 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 1 to 3 and Comparative Examples 1 to 17 of the present invention. It is an X-ray diffraction diagram showing a powder X-ray diffraction spectrum of oxytitanium phthalocyanine used in Examples 4 and 5 and Comparative Examples 18 to 20 of the present invention.

Explanation of symbols

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

Claims (9)

In an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support,
The photosensitive layer comprises a polyester resin having a repeating structure represented by the following formula (1) (hereinafter referred to as “first resin”), and a polyester resin and a polycarbonate resin having a structure different from the first resin. And at least one resin selected from the group (hereinafter referred to as “second resin”),
The second resin includes a repeating structure represented by the following formula (2).
An electrophotographic photosensitive member characterized by the above.

(Wherein ^(1), Ar 1 ~Ar ⁴ each independently have a substituent represents also arylene group, ^{X 1} represents a divalent group (including a single bond), ^{X 2} Represents a divalent group having 3 or less atoms (including a single bond).

(In the formula (2), R ¹ and R ² each independently represent a hydrogen atom or an alkyl group, and R ³ and R ⁴ each independently represent an alkyl group, provided that R ^{1 to} R ⁴ are They are not all the same group.)   2. The electrophotographic photosensitive member according to claim 1, wherein the weight of the second resin with respect to the total weight of the first resin and the second resin is 1% by weight or more and 70% by weight or less. .   The electrophotographic photosensitive member according to claim 1, wherein the second resin is a polycarbonate resin. The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the repeating structure represented by the formula (2) is represented by the following formula (3).

  The weight ratio of the repeating structure represented by the formula (3) contained in the polycarbonate resin to the polycarbonate resin is 70% by weight or more, according to claim 3 or 4, Electrophotographic photoreceptor.   The electrophotographic photosensitive member according to claim 1, wherein the electrostatic latent image is recorded by being exposed to monochromatic light having a wavelength of 380 to 500 nm. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, and an electrostatic latent image obtained by performing image exposure on the charged electrophotographic photosensitive member. An image forming apparatus comprising: an image exposure unit that forms a toner image; a developing unit that develops the electrostatic latent image with toner; and a transfer unit that transfers the toner to a transfer target.   The image forming apparatus according to claim 7, wherein an exposure wavelength of the image exposure unit that forms an electrostatic latent image is monochromatic light of 380 to 500 nm.   The electrophotographic photosensitive member according to any one of claims 1 to 6, a charging unit for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to image exposure to form an electrostatic latent image. An electrophotographic cartridge comprising: at least one of an image exposure unit to be formed, a developing unit for developing the electrostatic latent image with toner, and a transfer unit for transferring the toner to a transfer target.

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