JP6953694B2 - Electrophotographic photosensitive member, electrophotographic cartridge and image forming apparatus - Google Patents

Description

The present invention relates to an electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member having good wear resistance.

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., the electrophotographic photosensitive member is deteriorated by receiving various stresses during that period. Such deterioration includes, for example, chemical damage caused by strongly oxidizing ozone and NOx generated from a corona charger commonly used as a charger to the photosensitive layer, and carriers (currents) generated by image exposure in the photosensitive layer. There is chemical or electrical deterioration such as decomposition of the photosensitive layer composition due to flowing inside or due to static elimination light and light from the outside. Further, there is mechanical deterioration such as abrasion of the surface of the photosensitive layer due to rubbing of a cleaning blade, a magnetic brush or the like, contact with a developing agent or paper, generation of scratches, and peeling of a film. Damage due to such mechanical deterioration tends to appear on the image and directly impairs the image quality, which is a major factor in limiting the life of the photoconductor.

In the case of a general photoconductor without a functional layer such as a surface protective layer, the photosensitive layer is particularly susceptible to such a load. The photosensitive layer is usually composed of a binder resin and a photoconductive substance, and it is the binder resin that substantially determines the strength. However, since the amount of the photoconductive substance doped is considerably large, sufficient mechanical strength is provided. Has not reached. As the binder resin of the photosensitive layer, a polycarbonate resin having excellent electrical characteristics and abrasion resistance is used, and in recent years, an electrophotographic photosensitive member using a polycarbonate resin having improved abrasion resistance has been developed (Patent Documents). See 1-3).

On the other hand, when divalent phenol having an aromatic ester bond is used as a raw material monomer, the aromatic ester bond is used for hydrolysis in the interfacial polymerization method, which is a general method for producing a polyester resin for an electrophotographic photosensitive member. I can't. Therefore, there are few cases in which a polycarbonate resin containing a divalent phenol residue structure having an aromatic ester bond is used for the photoconductor, and the characteristics have not been clarified (Patent Document 4).

Japanese Unexamined Patent Publication No. 2011-26575 WO2013 / 027654 Japanese Unexamined Patent Publication No. 2015-102763 Japanese Unexamined Patent Publication No. 2000-352830

However, according to the study of the present inventor, the photoconductor using the polycarbonate resin of the techniques described in Patent Documents 1 to 3 has a high mechanical strength in a high-life and high-speed model such as printing 100,000 sheets or more. It wasn't enough.
Further, the technique described in Patent Document 4 uses a polycarbonate resin containing a divalent phenol residue having an ester structure for the photoconductor, but because it is copolymerized with a divalent phenol having a bulky triarylamine structure. The entanglement of the resin was weakened, and the abrasion resistance was insufficient.

The present invention has been made in view of the above problems. That is, an object of the present invention is to provide an electrophotographic photosensitive member having excellent wear resistance and electrical characteristics against a practical load.

As a result of diligent studies on an electrophotographic photosensitive member that can solve the above problems, the present inventors have excellent mechanical properties by incorporating a polycarbonate resin having a specific chemical structure in the photosensitive layer. Based on this finding, they have found that an electrophotographic photosensitive member having high solubility in a solvent used for a coating liquid for forming a photosensitive layer, excellent coating liquid stability, and excellent electrical characteristics can be obtained. The present invention has been completed. That is, the gist of the invention lies in the following [1] to [7].

[1]
An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer is a polycarbonate resin containing a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2). An electrophotographic photosensitive member comprising.

(In the formula (1), Ar ¹ and Ar ² represent an arylene group which may independently have a substituent. Z ¹ is a divalent group having an aromatic group, and s is 0. Or an integer of 1.)

(In the formula (2), R ¹ and R ² independently represent any one of a hydrogen atom, a halogen group, a hydrocarbon group, and an alkoxy group, and the hydrocarbon group and the alkoxy group are some or all hydrogen. Atoms may be substituted with halogen groups. X ¹ represents a single bond, —CR ³ R ⁴ −, O, CO, or S, and R ³ and R ⁴ are independent hydrogen atoms and halogens, respectively. Represents any of a group, a hydrocarbon group, and an alkoxy group, and some or all of the hydrogen atoms of the hydrocarbon group and the alkoxy group may be substituted with a halogen group, and R ³ and R ⁴ are , M ¹ and m ² may independently represent integers of 0 or more and 4 or less, respectively.)

[2]
In the polycarbonate resin, the ratio of the repeating unit represented by the formula (1) to the total of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) is 1 mol% or more. The electrophotographic photosensitive member according to [1], which has a content of 50 mol% or less.

[3]
The repeating unit represented by the formula (1) is the repeating unit represented by the following formula (3) or (4).
The electrophotographic photosensitive member according to [1] or [2], which is a repeating unit represented by).

In the formula (3), R ⁵ and R ⁶ independently represent any one of a hydrogen atom, a halogen group, an alkyl group, and an alkoxy group, and some or all of the hydrogen atoms of the alkyl group and the alkoxy group are halogen. It may be substituted with a group. m ³ and m ⁴ independently represent integers of 0 or more and 4 or less.

In formula (4), Ar ³ represents an arylene group which may have a substituent. R ⁷ and R ⁸ each independently represent one of a hydrogen atom, a halogen group, an alkyl group, and an alkoxy group, and the alkyl group and the alkoxy group have some or all hydrogen atoms substituted with halogen groups. May be good. m ⁵ and m ⁶ independently represent integers of 0 or more and 4 or less.

[4]
The electrophotographic photosensitive member according to any one of [1] to [3], the charging means for charging the electrophotographic photosensitive member, and the charged electrophotographic photosensitive member are subjected to image exposure to perform an electrostatic latent image. An electrophotographic cartridge comprising at least one of an image exposing means for forming an image, a developing means for developing the electrostatic latent image with toner, and a transfer means for transferring the toner to a transfer target.

[5]
An electrostatic latent image is formed by exposure to the electrophotographic photosensitive member according to any one of [1] to [3], a charging means for charging the electrophotographic photosensitive member, and the charged electrophotographic photosensitive member. It is provided with an exposure means, a developing means for developing the electrostatic latent image with toner, a transfer means for transferring the toner to a transfer target, and a fixing means for fixing the toner transferred to the transfer target. An image forming apparatus as a feature.

[6]
The method for producing a polycarbonate resin according to any one of [1] to [3].
[7]
The method for producing a polycarbonate resin according to [6], which comprises solution polymerization in the production process.

The polycarbonate resin has high solubility in a solvent used for a coating liquid for forming a photosensitive layer and excellent coating liquid stability, and the photoconductor of the present invention using the polycarbonate resin has various aspects such as abrasion resistance and electrical characteristics. It has excellent characteristics. Although the reason for this improvement in wear resistance is not clear, the divalent phenol residue having an ester bond in the repeating unit represented by the above formula (1) is a molecule due to the influence of its aromatic group and polar group. It is considered that the resin chains are easily entangled with each other and the mechanical properties of the resin are improved. On the other hand, in the case of a resin having only a repeating structure represented by the above formula (1), the interaction becomes too strong and the resin becomes a crystalline resin, which becomes insoluble in an organic solvent and is difficult to use for an electrophotographic photosensitive member. .. Therefore, by copolymerizing with the repeating unit represented by the formula (2), a polycarbonate resin having excellent mechanical properties and solubility in an organic solvent can be obtained, and a photoconductor having excellent wear resistance can be obtained. ..

According to the present invention, an electrophotographic photosensitive member having particularly excellent wear resistance and excellent electrical characteristics can be obtained, and by using the electrophotographic photosensitive member, an excellent cartridge and an image forming apparatus can be obtained.

It is a conceptual diagram which shows one Example of the image forming apparatus using the electrophotographic photosensitive member of this invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist thereof.

≪Polycarbonate resin≫
The photosensitive layer of the electrophotographic photosensitive member to which the present embodiment is applied contains a polycarbonate resin containing a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2).

In the formula (1), Ar ¹ and Ar ² represent an arylene group which may have an independently substituent. Z ¹ is a divalent group having an aromatic group, and s is an integer of 0 or 1.

In the formula (2), R ¹ and R ² independently represent any one of a hydrogen atom, a halogen group, a hydrocarbon group, and an alkoxy group, and the hydrocarbon group and the alkoxy group are some or all hydrogen atoms. May be substituted with a halogen group. X ¹ is a single ^{bond, -CR 3 R 4 -, O} , CO
, Or S. Further, R ³ and R ⁴ independently represent any one of a hydrogen atom, a halogen group, a hydrocarbon group, and an alkoxy group, and in the hydrocarbon group and the alkoxy group, a part or all of the hydrogen atoms are replaced with a halogen group. It may have been. Further, R ³ and R ⁴ may be coupled to each other to form a ring. m ¹ and m ² independently represent integers of 0 or more and 4 or less.

In the formula (1), the ^{number of carbon atoms of the arylene group which may have the substituents of Ar 1} and Ar ² is not particularly limited, but is usually 6 or more, while usually 20 or less, preferably 16 or less, more preferably. Is 12 or less. Especially preferably 6. The above range is preferable because it has excellent wear resistance and electrical characteristics.
Specific examples of the arylene group which may have a substituent include a phenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, a pyrenylene group, a biphenylene group and the like. A phenylene group, a naphthylene group, and a biphenylene group are preferable from the viewpoint of electrical characteristics, and a phenylene group is preferable from the viewpoint of solubility. Examples of the substituent include an alkyl group, an alkoxy group, an alkyl halide group, a halogen group, a benzyl group and the like. Among these substituents, the alkyl group, the alkoxy group, and the alkyl halide group usually have 1 or more carbon atoms, while usually 10 or less, preferably 8 or less, more preferably 6 or less, and further preferably 4 or less. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, an isobutyl group, a cyclohexyl group and the like. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a cyclohexoxy group and the like. Examples of the alkyl halide group include a chloroalkyl group and a fluoroalkyl group. Examples of the halogen group include a fluoro group, a chloro group, a bromo group and the like. More preferably, it is a methyl group or an ethyl group. From the viewpoint of wear resistance, an arylene group having no substituent is more preferable.

The number of substituents for each of Ar ¹ and Ar ² is not particularly limited, but is preferably 4 or less, more preferably 3 or less, and particularly preferably 2 or less. From the viewpoint of electrical characteristics, Ar ¹ and Ar ² are more preferably unsubstituted arylene groups, and from the viewpoint of wear resistance, Ar ¹ and Ar ² are more preferably the same unsubstituted arylene groups. From the viewpoint of solubility, it is particularly preferable to use an unsubstituted phenylene group.

In ^{the case of a phenylene group in which Ar 1} and Ar ² may have a substituent, an m-phenylene group and a p-phenylene group are preferable, and a p-phenylene group is more preferable from the viewpoint of abrasion resistance. In the case of a naphthylene group which may have a substituent, 1,3-naphthylene group, 1,4-naphthylene group, 1,5-naphthylene group, 1,6-naphthylene group, 1,7-naphthylene group, 2, 4-naphthylene group, 2,5-naphthylene group, 2,6-naphthylene group, 2,7-naphthylene group are preferable, and 1,6-naphthylene group, 1,7-naphthylene group, 2, from the viewpoint of abrasion resistance. A 6-naphthylene group and a 2,7-naphthylene group are more preferable. In the case of a biphenylene group, a 2,4-biphenylene group, a 2,2'-biphenylene group, a 3,3'-biphenylene group, a 4,4'-biphenylene group, and a 2,4'-biphenylene group are preferable, and the abrasion resistance is high. From the viewpoint, a 4,4'-biphenylene group is more preferable.

Z ¹ is not particularly limited as long as it is a divalent group having an aromatic group, but from the viewpoint of achieving both wear resistance and electrical characteristics, Ar ¹ and the following formula (5) are preferable.

In the formula (5), R ⁹ and R ¹⁰ independently represent any one of a hydrogen atom, a halogen group, a hydrocarbon group, and an alkoxy group, and the hydrocarbon group and the alkoxy group are some or all hydrogen atoms. May be substituted with a halogen group. X ² represents a single bond, —CR ¹¹ R ¹² −, O, CO, or S. Further, R ¹¹ and R ¹² independently represent any one of a hydrogen atom, a halogen group, a hydrocarbon group, and an alkoxy group, and in the hydrocarbon group and the alkoxy group, a part or all of the hydrogen atoms are replaced with a halogen group. It may have been. Further, R ¹¹ and R ¹² may be coupled to each other to form a ring. m ⁷ and m ⁸ independently represent integers of 0 or more and 4 or less.

Examples of the halogen group of R ⁹ and R ¹⁰ include a fluoro group, a chloro group and a bromo group, and a fluoro group is preferable from the viewpoint of ease of production and abrasion resistance.
The hydrocarbon groups of R ⁹ and R ¹⁰ are not particularly limited, and specific examples thereof include an alkyl group, an alkenyl group, an alkynyl group, and an aryl group, and an alkyl group and an aryl group are preferable. The number of carbon atoms of the hydrocarbon group is not particularly limited, but is usually 1 or more, while usually 20 or less, preferably 16 or less, more preferably 12 or less, still more preferably 10 or less, still more preferably 8 or less, and particularly preferably 6 or less. Is. In the case of an alkyl group, the number of carbon atoms is not particularly limited, but is usually 1 or more, while usually 20 or less, preferably 16 or less, more preferably 12 or less, still more preferably 10 or less, still more preferably 8 or less, still more preferable. Is 6 or less, particularly preferably 4 or less, and most preferably 1. In the case of an alkenyl group, the number of carbon atoms is not particularly limited, but is usually 1 or more, while usually 20 or less, preferably 16 or less, more preferably 12 or less, still more preferably 10 or less, still more preferably 8 or less, still more preferable. Is 6 or less, particularly preferably 4 or less, and most preferably 2. In the case of an alkynyl group, the number of carbon atoms is not particularly limited, but is usually 1 or more, while usually 20 or less, preferably 16 or less, more preferably 12 or less, still more preferably 10 or less, still more preferably 8 or less, still more preferable. Is 6 or less, particularly preferably 4 or less, and most preferably 2. In the case of an aryl group, the number of carbon atoms is not particularly limited, but is usually 6 or more, while usually 20 or less, preferably 16 or less, more preferably 14 or less, still more preferably 12 or less, still more preferably 10 or less, particularly preferably. Is 8 or less, most preferably 6. The above range is preferable from the viewpoint of manufacturing convenience and wear resistance.

Specific examples of the alkyl group of R ⁹ and R ¹⁰ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, a cyclohexyl group and the like, and a methyl group and an ethyl group are preferable. , More preferably a methyl group. Alkyl groups in which some or all hydrogen atoms are substituted with halogen groups include fluoromethyl group, difluoromethyl group, trifluoromethyl group, fluoroethyl group, difluoroethyl group, trifluoroethyl group, and tetrafluoroethyl group. , Pentafluoroethyl group, preferably a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, and more preferably a trifluoromethyl group. Examples of the aryl group include a phenyl group, a methylphenyl group, a dimethylphenyl group and a naphthyl group, and examples of the aryl group in which some or all of the hydrogen atoms are substituted with a halogen group include a halogenated phenyl group. It is preferably a fluorophenyl group. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a cyclohexoxy group and the like. The above-mentioned substituent is preferable from the viewpoint of ease of manufacture and abrasion resistance.

When R ¹¹ and R ¹² are any of hydrogen atoms, halogen groups, hydrocarbon groups, and alkoxy groups, R ¹¹ and R ¹² are synonymous with ^{R 9} and R ^10. When R ¹¹ and R ¹² are bonded to each other to form a ring, the number of carbon atoms is not particularly limited, but is usually 5 or more, preferably 6 or more, while usually 20 or less, preferably 16 or less, more preferably 12. Hereinafter, it is more preferably 10 or less, and even more preferably 8 or less. Specific examples of the case where R ¹¹ and R ¹² are bonded to each other to form a ring include a cycloalkylidene group, and a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group are preferable. It is also preferable that the hydrocarbon group is further substituted with these substituents, and as a specific example thereof, a 3,3,5-trimethylcyclohexylidene group is preferable.

From the viewpoint of wear resistance, m ⁷ and m ⁸ are preferably 0 or more and 2 or less, and more preferably 0 or 1.
When m ⁷ and m ⁸ are integers from 0 to 3, the unsubstituted site represents a hydrogen atom. For example, m ⁷ = 4 and R ⁹ are all hydrogen atoms, and m ⁷ = 0 is synonymous. Similarly, m ⁸ = 4 and R ¹⁰ are all hydrogen atoms, and m ⁸ = 0 is synonymous.

The formula (1) is preferably a repeating unit selected from the repeating units represented by the following formula (3) or (4).

In the formula (3), R ⁵ and R ⁶ independently represent any one of a hydrogen atom, a halogen group, an alkyl group, and an alkoxy group, and some or all of the hydrogen atoms of the alkyl group and the alkoxy group are halogen. It may be substituted with a group. m ³ and m ⁴ independently represent integers of 0 or more and 4 or less.

In formula (4), Ar ³ represents an arylene group which may have a substituent. R ⁷ and R ⁸ each independently represent one of a hydrogen atom, a halogen group, an alkyl group, and an alkoxy group, and the alkyl group and the alkoxy group have some or all hydrogen atoms substituted with halogen groups. May be good. m ⁵ and m ⁶ independently represent integers of 0 or more and 4 or less.
m ³ and m ⁴ are preferably 2 or less, more preferably 1 or less, and particularly preferably 0. m ⁵ and m ⁶ are preferably 2 or less, more preferably 1 or less, and particularly preferably 0.

Ar ³ is synonymous with ^{Ar 1.}
Examples of the halogen group of R ^{5 to} R ⁸ include a fluoro group, a chloro group and a bromo group, and a fluoro group is preferable from the viewpoint of ease of production and abrasion resistance.
When R ^{5 to} R ⁸ are alkyl groups, the number of carbon atoms is not particularly limited, but usually 1 or more, while usually 20 or less, preferably 16 or less, more preferably 12 or less, still more preferably 10 or less.
It is even more preferably 8 or less, even more preferably 6 or less, particularly preferably 4 or less, and most preferably 1. The above range is preferable from the viewpoint of manufacturing convenience and wear resistance.

Specific examples of the alkyl group of R ^{5 to} R ⁸ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, a cyclohexyl group and the like, and a methyl group and an ethyl group are preferable. , More preferably a methyl group. Alkyl groups in which some or all hydrogen atoms are substituted with halogen groups include fluoromethyl group, difluoromethyl group, trifluoromethyl group, fluoroethyl group, difluoroethyl group, trifluoroethyl group, and tetrafluoroethyl group. , Pentafluoroethyl group, preferably a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, and more preferably a trifluoromethyl group. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a cyclohexoxy group and the like. The above-mentioned substituent is preferable from the viewpoint of ease of manufacture and abrasion resistance.

Specific examples of the divalent phenol compound for inducing the divalent phenol residue represented by the formula (1) are shown below.

Among these, the following compounds are more preferable from the viewpoint of electrical characteristics.

Further, the structure shown below is particularly preferable from the viewpoint of wear resistance.

In the formula (2), R ¹ and R ² independently represent any one of a hydrogen atom, a halogen group, a hydrocarbon group, and an alkoxy group, and the hydrocarbon group and the alkoxy group are some or all hydrogen atoms. May be substituted with a halogen group. X ¹ represents a single ^bond, -CR ³ R 4 -, represents O, CO, or S. Further, R ³ and R ⁴ independently represent any one of a hydrogen atom, a halogen group, a hydrocarbon group, and an alkoxy group, and in the hydrocarbon group and the alkoxy group, a part or all of the hydrogen atoms are replaced with a halogen group. It may have been. Further, R ³ and R ⁴ may be coupled to each other to form a ring. m ¹ and m ² independently represent integers of 0 or more and 4 or less.

Examples of the halogen group of R ¹ and R ² include a fluoro group, a chloro group and a bromo group, and a fluoro group is preferable from the viewpoint of ease of production and abrasion resistance.
The hydrocarbon groups of R ¹ and R ² are not particularly limited, and specific examples thereof include an alkyl group, an alkenyl group, an alkynyl group, and an aryl group, and an alkyl group and an aryl group are preferable. The number of carbon atoms of the hydrocarbon group is not particularly limited, but is usually 1 or more, while usually 20 or less, preferably 16 or less, more preferably 12 or less, still more preferably 10 or less, still more preferably 8.
Below, it is particularly preferably 6 or less. In the case of an alkyl group, the number of carbon atoms is not particularly limited, but is usually 1 or more, while usually 20 or less, preferably 16 or less, more preferably 12 or less, still more preferably 10 or less, still more preferably 8 or less, still more preferable. Is 6 or less, particularly preferably 4 or less, and most preferably 1. In the case of an alkenyl group, the number of carbon atoms is not particularly limited, but is usually 1 or more, while usually 20 or less, preferably 16 or less, more preferably 12 or less, still more preferably 10 or less, still more preferably 8 or less, still more preferable. Is 6 or less, particularly preferably 4 or less, and most preferably 2. In the case of an alkynyl group, the number of carbon atoms is not particularly limited, but is usually 1 or more, while usually 20 or less, preferably 16 or less, more preferably 12 or less, still more preferably 10 or less, still more preferably 8 or less, still more preferable. Is 6 or less, particularly preferably 4 or less, and most preferably 2. In the case of an aryl group, the number of carbon atoms is not particularly limited, but is usually 6 or more, while usually 20 or less, preferably 16 or less, more preferably 14 or less, still more preferably 12 or less, still more preferably 10 or less, particularly preferably. Is 8 or less, most preferably 6. The above range is preferable from the viewpoint of manufacturing convenience and wear resistance.

Specific examples of the alkyl group of R ¹ and R ² include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, a cyclohexyl group and the like, and a methyl group and an ethyl group are preferable. , More preferably a methyl group. Alkyl groups in which some or all hydrogen atoms are substituted with halogen groups include fluoromethyl group, difluoromethyl group, trifluoromethyl group, fluoroethyl group, difluoroethyl group, trifluoroethyl group, and tetrafluoroethyl group. , Pentafluoroethyl group, preferably a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, and more preferably a trifluoromethyl group. Examples of the aryl group include a phenyl group, a methylphenyl group, a dimethylphenyl group and a naphthyl group, and examples of the aryl group in which some or all of the hydrogen atoms are substituted with a halogen group include a halogenated phenyl group. It is preferably a fluorophenyl group. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a cyclohexoxy group and the like. The above-mentioned substituent is preferable from the viewpoint of ease of manufacture and abrasion resistance.

When R ³ and R ⁴ are any of hydrogen atoms, halogen groups, hydrocarbon groups, and alkoxy groups, R ³ and R ⁴ are synonymous with ^{R 1} and R ^2. When R ⁶ and R ⁷ are bonded to each other to form a ring, the number of carbon atoms is not particularly limited, but is usually 5 or more, preferably 6 or more, while usually 20 or less, preferably 16 or less, more preferably 12. Hereinafter, it is more preferably 10 or less, and even more preferably 8 or less. Specific examples of the case where R ⁶ and R ⁷ are bonded to each other to form a ring include a cycloalkylidene group, and a cyclopentylidene group, a cyclohexylidene group, and a cycloheptilidene group are preferable. It is also preferable that the hydrocarbon group is further substituted with these substituents, and as a specific example thereof, a 3,3,5-trimethylcyclohexylidene group is preferable.

From the viewpoint of wear resistance, m ¹ and m ² are preferably 0 or more and 2 or less, and more preferably 0 or 1.
When m ¹ and m ² are integers from 0 to 3, the unsubstituted site represents a hydrogen atom. For example, m ¹ = 4 and R ⁴ are all hydrogen atoms, and m ¹ = 0 is synonymous. Similarly, m ² = 4 and R ⁵ are all hydrogen atoms, and m ² = 0 is synonymous.

The repeating unit represented by the formula (2) is preferably a repeating unit represented by the following formula (6) from the viewpoint of electrical characteristics and wear resistance.

Specific examples of the divalent phenol that is the source of the divalent phenol residue represented by the formula (2) are bis- (4-hydroxyphenyl) methane and bis- (4-hydroxy-3-methylphenyl). Methan, bis- (3,5-dimethyl-4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane, 1,1-bis- (3,5-dimethyl-4-hydroxyphenyl) ethane, 1,1-bis- (4-hydroxyphenyl) propane, 1,1-bis- (4-hydrokey 3-methylphenyl) propane , 1,1-bis- (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydrokey 3-methylphenyl) Propane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) propane, 1,1-bis- (4-hydroxyphenyl) cyclohexane, 1,1-bis- (4-hydrokey 3-methylphenyl) ) Cyclohexane, 1,1-bis- (3,5-dimethyl-4-hydroxyphenyl) cyclohexane, 1,1-bis- (4-hydroxyphenyl) -1-phenylethane, 4,4'-biphenol, 3, 3'-dimethyl-4,4'-biphenol, 3,3', 5,5'-tetramethyl-4,4'-biphenol, 4,4'-dihydroxydiphenyl ether, 3,3'-dimethyl-4,4 ′ -Dihydroxydiphenyl ether, bis (4-hydroxyphenyl) sulfide, 4,4′-dihydroxybenzophenone, 2,2-bis (4-hydroxyphenyl) hexafluoropropane and the like can be mentioned. Among these, bis- (4-hydroxyphenyl) methane, bis- (4-hydroxy-3-methylphenyl) methane, bis- ( 3,5-Dimethyl-4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane, 2,2-bis -(4-Hydroxyphenyl) propane, 2,2-bis- (4-hydrokey 3-methylphenyl) propane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) propane, 1,1- Bis- (4-hydroxyphenyl) cyclohexane, 4,4'-biphenol, 3,3'-dimethyl-4,4'-biphenol, 3,3', 5,5'-tetramethyl-4,4'-biphenol , 4,4'-Dihydroxydiphenyl ether is preferred. Further considering the mechanical properties, bis- (4-hydroxyphenyl) methane, bis- (4-hydroxy-3-methylphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 1,1- Bis- (4-hydroxy-3-methylphenyl) ethane, 2,2-bis- (4-hydrokey 3-methylphenyl) propane, 4,4'-biphenol, 1,1-bis- (4-hydroxyphenyl) Cyclohexane is more preferred.

The polycarbonate resin in the present invention may have a repeating unit other than the repeating unit represented by the formula (1) and the repeating unit represented by the following formula (2), and may have a repeating unit represented by the formula (1). Examples of the divalent diol that is the basis of the repeating structure other than the unit and the repeating unit represented by the following formula (2) are ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,6-hexanediol. , 1,8-octanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl1,3-propanediol, 2-methyl-1,5-pentanediol, 3- Methyl-1,5-pentanediol, 1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4- Cyclohexanedimethanol, 1,4-dihydroxy-2-butene, perfluoroalkyl-containing diol, polysiloxane-containing diol, hydroquinone, methylhydroquinone, resorcinol, catechol, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1, 4-Dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 4-hydroxyphenyl 4-hydroxybenzoate, 1,4-bis (4-hydroxybenzoic acid) phenyl, 4,4'-bis ( 4-Hydroxybenzoic acid) biphenyl, 4,4'-bis (4-hydroxybenzoic acid) -3,3', 5,5'-tetramethyl-biphenyl and the like can be mentioned.

In the polycarbonate resin, the ratio of the repeating unit represented by the formula (1) to the total of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) is not particularly limited. However, it is usually 1 mol% or more, preferably 3 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more, while usually 50 mol% or less, preferably 47 mol% or less, more preferably 45 mol% or less. .. Within the above range, good solubility and coating solution stability can be obtained, and high wear resistance can be obtained.

The molar ratio ^{can be calculated from the 1} H-NMR spectrum of the polycarbonate resin.
The content of the repeating unit represented by the formula (1) in the polycarbonate resin is not particularly limited, but is usually 1 mol% or more, preferably 3 mol% or more, more preferably 5 mol% or more, while usually 50 mol% or less. It is preferably 45 mol% or less. The content of the repeating unit represented by the formula (2) in the polycarbonate resin is not particularly limited, but is preferably 50 mol% or more, more preferably 55 mol% or more. On the other hand, 99 mol% or less is preferable, 97 mol% or less is more preferable, and 95 mol% or less is further preferable. When the content is in the above range, the solubility and electrical characteristics are improved.

The molar ratio ^{can be calculated from the 1} H-NMR spectrum of the polycarbonate resin.
The copolymerization structure of the polycarbonate resin of the present invention may be any of a random copolymer, an alternating copolymer, and a copolymer having a partially block structure. From the viewpoint of solubility and stability of the coating liquid, a copolymer having a partially block structure is preferable.

The viscosity average molecular weight (Mv) of the polycarbonate resin is usually 10,000 or more, preferably 25,000 or more from the viewpoint of mechanical strength. Further, it is usually 200,000 or less, preferably 150,000 or less from the viewpoint of coatability.
The amount of chlorohomate groups present at the ends of the polycarbonate resin is usually 0.1 μe equivalent / g or less, preferably 0.05 μe equivalent / g or less. When the amount of the terminal chlorohomet group is within the above range, the stability of the coating liquid is good.

The amount of OH groups present at the ends of the polycarbonate resin is usually 50 μe equivalent / g or less, preferably 30 μe equivalent / g or less. By setting the amount of terminal OH groups in the above range, an electrophotographic photosensitive member having good electrical characteristics can be obtained.
The total amount of nitrogen (TN amount) contained in the polycarbonate resin is preferably 1000 ppm or less, more preferably 500 ppm or less, and particularly preferably 300 ppm or less. When the total amount of nitrogen is within the above range, an electrophotographic photosensitive member having excellent electrical characteristics during repeated use can be obtained.

The amount of the free divalent phenol contained in the resin is not particularly limited, but is preferably 100 ppm or less, more preferably 50 ppm or less. On the other hand, it is preferably 0.001 ppm or more, and particularly preferably 0.01 ppm or more. Within the above range, good electrical characteristics can be obtained and stability over time is excellent.
The polycarbonate resin and other resins can be mixed and used for the photosensitive layer in the electrophotographic photosensitive member to which the present embodiment is applied. Examples of the resin having another structure mixed here include vinyl polymers such as polymethylmethacrylate, polystyrene, and polyvinyl chloride and copolymers thereof; polycarbonate resin, polyester resin, polyester polycarbonate resin, polysulfone resin, and phenoxy. Examples thereof include thermoplastic resins such as resins, epoxy resins and silicone resins, various thermosetting resins and the like, and copolymers thereof. Among these resins, a polycarbonate resin, a polyester resin, a copolymer of a polycarbonate resin and a silicone resin, and a copolymer of a polyester resin and a silicone resin are preferable. The mixing ratio of the resin having another structure to be mixed is not particularly limited, but it is usually preferable to use the resin in combination within a range not exceeding the ratio of the polycarbonate resin, and specifically, the other structure with respect to the polycarbonate resin. The content of the resin having is usually 50 parts by mass or less, preferably 30 parts by mass or less from the viewpoint of abrasion resistance.

Specific examples of suitable structures of the resin having the other structure are shown below. These specific examples are shown for illustration purposes, and any binder resin may be mixed and used as long as it does not contradict the gist of the present invention.

≪Manufacturing method of polycarbonate resin≫
Next, a method for producing a polycarbonate resin used for the electrophotographic photosensitive member to which the present embodiment is applied will be described. When producing polycarbonate for an electrophotographic photosensitive member, it is generally produced by an interfacial polymerization method. However, when the polycarbonate resin of the present invention is produced, a divalent phenol having an ester bond is used as a raw material. Therefore, in the interfacial polymerization method, when the divalent phenol which has become an alkali salt is dissolved in the aqueous layer, It is rapidly hydrolyzed by a nucleophilic agent such as hydroxide ion, and polymerization does not proceed. Therefore, the method for producing a polycarbonate resin in the present invention preferably includes at least solution polymerization in the production process. Since solution polymerization can form a carbonate bond in a non-aqueous solvent, a polycarbonate resin can be produced without hydrolyzing the ester bond contained in the monomer. An example of a method for producing a polycarbonate resin will be described below.

<Solution polymerization process>
In the solution polymerization step, for example, in the presence of a divalent phenol compound and a phosgene or a polycarbonate oligomer having a chlorohomate group at the terminal, a base such as triethylamine can be added to form a carbonate bond to extend the resin chain. can. The polycarbonate resin may be produced only by the solution polymerization step, or the oligomer may be produced by the solution polymerization step, and then the polycarbonate resin may be produced by interfacial polymerization or the like.

The oligomer can be produced by a known technique, and examples thereof include the method described in Example 1 of JP-A-2010-432201 and the method described in Production Example 1 of JP-A-2011-26575.
Examples of the base used in the solution polymerization method include triethylamine, tripropylamine, tributylamine, N, N-diisopropylethylamine, N, N-dipropylethylamine, N, N-diethylmethylamine, N, N-dimethylethylamine. , N, N-dimethylbutylamine, N, N-dimethylisopropylamine, N, N-diethylisopropylamine, N, N, N', N'-tetramethyldiethylamine, 1,4-diazabicyclo [2,2,2] Examples thereof include tertiary amines such as octane, pyridines such as pyridine and 4-methylpyridine, and organic bases such as 1,8-diazabicyclo [5.4.0] -7-undecene. Further, the base is not particularly limited as long as it is a base used in a carbonated reaction such as a phosphazene base or an inorganic base. Among these bases, triethylamine, N, N-diisopropylethylamine, N, N-diisopropylethylamine, and pyridine are preferable from the viewpoint of the reactivity of the carbonate reaction and the ease of acquisition, and the decomposition of chlorohomed groups is suppressed and the washing is performed. Triethylamine and N, N-diisopropylethylamine are particularly preferable from the viewpoint of ease of removal. The amount of the base used is preferably in the range of 1.0 times equivalent to 2 times equivalent of the amount of hydroxyl groups contained in the reaction system. Within the above range, the reaction can proceed rapidly and the decomposition of carbonate bonds and ester bonds can be suppressed.

Examples of the solvent include halogenated hydrocarbon compounds such as dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, chlorobenzene and dichlorobenzene, aromatic hydrocarbon compounds such as toluene, anisole and xylene, cyclohexane and methylcyclohexane. Hydrocarbon compounds, ether compounds such as tetrahydrofuran, tetrahydropyran, 1,4-dioxane, 1,3-dioxolane, ester compounds such as ethyl acetate, methyl benzoate, benzyl acetate, N, N-dimethylformamide, N, N- Examples thereof include amide compounds such as dimethylacetamide. Further, pyridine may be used as a base and a solvent. Among these, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydrofuran, N, N-dimethylformamide, and pyridine are preferable from the viewpoint of the solubility of the monomer and the oligomer produced and the reactivity of the esterification reaction. Further, dichloromethane is particularly preferable from the viewpoint of cleaning efficiency and electrical characteristics.

The polymerization temperature is preferably in the range of −10 ° C. to 40 ° C., and the polymerization time is preferably in the range of 0.5 to 10 hours from the viewpoint of productivity.
Further, the divalent phenol which is the source of the repeating structural unit represented by the above formula (1) may have poor solubility in a solvent, and precipitates when it reacts with phosgene, resulting in cloudiness and high molecular weight of the reaction solution. It may be an obstacle. Therefore, the present divalent phenol and the divalent phenol which is the source of the repeating structure represented by the above formula (2) are reacted together with phosgen, or the oligomer composed of the divalent phenol which is the source of the formula (2) is reacted. , It is preferable to react the divalent phenol which is the basis of the formula (1).

<Interfacial polymerization process>
An interfacial polymerization step may be included in the production of the polycarbonate resin of the present invention. It is preferable that the oligomer produced in the solution polymerization step is used in the interfacial polymerization step, and then used in the subsequent production of the polycarbonate resin.
In the interfacial polymerization step, for example, an alkaline aqueous solution is mixed with a solution of a halogenated hydrocarbon or an aromatic hydrocarbon in which an oligomer obtained by the solution polymerization is dissolved. At this time, it is also possible to make a tertiary amine, a quaternary ammonium salt or a quaternary phosphonium salt present as a catalyst. The polymerization temperature is preferably in the range of 0 ° C. to 40 ° C., and the polymerization time is preferably in the range of 0.5 hour to 20 hours from the viewpoint of productivity. After completion of the polymerization, the aqueous phase and the organic phase are separated, and the polymer dissolved in the organic phase is washed and recovered by a known method to obtain the desired resin.

In the case of production by interfacial polymerization, it is also possible to add a divalent phenol other than the oligomer to the alkaline aqueous solution, if necessary.
Examples of the alkaline component used in the interfacial polymerization method include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide. The amount of the alkaline component used is preferably in the range of 1.01 times to 3 times the equivalent of the chlorohomate group contained in the reaction system.

Examples of the halogenated hydrocarbon as the reaction organic solvent include dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, dichlorobenzene and the like. Examples of aromatic hydrocarbons include toluene, xylene, benzene and the like.
As tertiary amines used as catalysts, for example, triethylamine, tripropylamine, tributylamine, N, N-diisopropylethylamine, N, N-dipropylethylamine, N, N-diethylmethylamine, N, N-dimethylethylamine, N, N-dimethylbutylamine, N, N-dimethylisopropylamine, N, N-diethylisopropylamine, N, N, N', N'-tetramethyldiethylamine, 1,4-diazabicyclo [2,2,2] octane And so on. Triethylamine is preferable because it provides reactivity and a high molecular weight resin.

Examples of the quaternary ammonium salt and the quaternary phosphonium salt used as a catalyst include salts of tertiary alkylamines such as tributylamine and trioctylamine such as hydrochloric acid, bromic acid and iodic acid; benzyltriethylammonium chloride and benzyltrimethylammonium. Chloride, benzyltributylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, trioctylmethylammonium chloride, tetrabutylphosphonium bromide, triethyloctadecylphosphonium bromide, N-laurylpyridinium chloride, laurylpicolinium chloride, etc. Be done.

<Common items for polycarbonate resin manufacturing>
A molecular weight modifier can be used in the production of the polycarbonate resin. Examples of the molecular weight modifier 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 derivative, 2-methylphenol derivative; monofunctional phenols such as o, m, p-phenylphenol; 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 their substitutes. In addition, monofunctional aliphatic alcohols such as methanol, ethanol and propanol, and monofunctional alcohols having acrylics such as 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate and 2-hydroxymethacrylate, 1H, 1H, 2H and 2H- Examples thereof include monofunctional alcohols having perfluoroalkyl such as tridecafluoro-1-n-octanol, 1H, 1H, 2H and 2H-heptadecafluoro-1-decanol, and monofunctional alcohols having siloxane. Among these molecular weight modifiers, o, m, p- (tert-butyl) phenol, 2,6-dimethylphenol derivative, and 2-methylphenol are preferable in terms of high molecular weight control ability and solution stability. It is a derivative. Particularly preferred are p- (tert-butyl) phenol, 2,3,6-trimethylphenol and 2,3,5-trimethylphenol.

Further, in order not to oxidize the divalent phenol, an antioxidant can be added during the polymerization reaction or in the cleaning liquid. Examples of the antioxidant include sodium sulfite, hydrosulfite (sodium hyposulfite), sulfur dioxide, potassium sulfite, sodium hydrogen sulfite and the like. Among these, hydrosulfite is particularly preferable from the viewpoint of antioxidant effect and reduction of environmental load. The amount of the antioxidant used is preferably 0.01% by mass or more and 10.0% by mass or less with respect to the total divalent phenol. More preferably, it is 0.1% by mass or more and 5% by mass or less.

As the cleaning method after the polymerization of the polycarbonate resin, any method can be used as long as the effect of the present invention is not significantly impaired. For example, the solution of the polycarbonate resin is an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide; hydrochloric acid, An aqueous acid solution such as nitric acid or phosphoric acid; a method of separating the solution by static separation, centrifugation or the like after washing with water or the like can be mentioned. Further, the polycarbonate resin solution may be purified by a method of circulating it on an adsorption column or the like.

The cleaning polycarbonate resin solution is prepared by precipitating the polycarbonate resin solution in water, alcohol or other organic solvent insoluble in the polycarbonate resin, distilling off the solvent in warm water or a dispersion medium in which the polycarbonate resin is insoluble, or heating the solution of the polycarbonate resin. It may be taken out by distilling off the solvent by reducing the pressure or the like, or when it is taken out in the form of a slurry, the solid can be taken out by a centrifuge or a filter.

The polycarbonate resin is usually dried at a temperature equal to or lower than the decomposition temperature of the polyester resin, but is preferably dried at 20 ° C. or higher and lower than the melting temperature of the polyester resin. At this time, it is preferable to dry under reduced pressure. The drying time is preferably time for the purity of impurities such as the residual solvent to be constant or less, and specifically, the time for the residual solvent to be usually 1000 ppm or less, preferably 300 ppm or less, and more preferably 100 ppm or less. dry.

≪Electrophotophotoreceptor≫
The electrophotographic photosensitive member to which the present embodiment is applied has a photosensitive layer provided on a conductive support, and the photosensitive layer contains the polycarbonate resin. As a specific configuration of the photosensitive layer, for example, a charge generating layer containing a charge generating substance as a main component and a charge transporting layer containing a charge transporting substance and a binder resin as a main component are laminated on a conductive support. Type Photoreceptor; Examples thereof include a dispersed type (single layer type) photoconductor having a photosensitive layer in which a charge generating substance is dispersed in a layer containing a charge transporting substance and a binder resin on a conductive support. The polycarbonate resin is usually used for a layer containing a charge-transporting substance, and is preferably used for a charge-transporting layer of a laminated photoconductor.

<Conductive support>
The conductive support is not particularly limited, but for example, a metal material such as aluminum, aluminum alloy, stainless steel, copper, or nickel, or a conductive powder such as metal, carbon, or tin oxide is added to impart conductivity. Resin materials and resins, glass, paper and the like on which a conductive material such as aluminum, nickel or ITO (indium oxide tin oxide) is vapor-deposited or coated on the surface thereof are mainly used. One of these may be used alone, or two or more thereof may be used in any combination and ratio. As the form of the conductive support, 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 for controlling conductivity, surface properties, etc. and covering defects.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after being anodized. When the anodic oxide film is applied, it is desirable to perform the hole 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 by applying a polishing treatment. Further, the surface may be roughened by mixing particles having an appropriate particle size with the material constituting the support. Further, in order to reduce the cost, it is possible to use the drawn pipe as it is without cutting.

<Underlay layer>
An undercoat layer may be provided between the conductive support and the photosensitive layer described later in order to improve adhesiveness, blocking property, and the like. As the undercoat layer, a resin, a resin in which particles such as metal oxides are dispersed, or the like is used. Further, the undercoat layer may be composed of a single layer or a plurality of layers. The undercoat layer may contain pigment particles, resin particles, etc., such as a known antioxidant, and may be used. The film thickness is usually 0.01 μm or more, preferably 0.1 μm or more, and is preferably 0.1 μm or more, from the viewpoint of improving the electrical characteristics, strong exposure characteristics, image characteristics, repeatability, and coatability during manufacturing of the electrophotographic photosensitive member. , Usually 30 μm or less, preferably 20 μm or less.

Examples of the metal oxide particles used for the undercoat layer include metal oxide particles containing one kind of metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, and iron oxide, calcium titanate, and titanium. Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid acid and barium titanate. These may use one kind of particles alone, or may use a plurality of kinds of particles in combination. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide or silicon oxide, or an organic substance such as stearic acid, polyol or silicon. As the crystal type of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Further, a plurality of crystalline states may be included.

Although various particle sizes of the metal oxide particles can be used, the average primary particle size is preferably 10 nm or more and 100 nm or less, and particularly 10 nm or more and 50 nm or less from the viewpoint of characteristics and liquid stability. preferable. This average primary particle size can be obtained from a TEM photograph or the like.
It is desirable that the undercoat layer is formed by dispersing the metal oxide particles in the binder resin. Binder resins used for the undercoat layer include epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, and chloride. Cellulous esters such as vinylidene resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacrylic resin, polyacrylamide resin, polyvinylpyrrolidone resin, polyvinylpyridine resin, water-soluble polyester resin, and nitrocellulose. Organic zirconium compounds such as resins, cellulose ether resins, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compounds, zirconium alkoxide compounds, organic titanyl compounds such as titanyl chelate compounds and titanium alkoxide compounds, silane coupling Examples thereof include known binder resins such as agents. These may be used alone, or two or more thereof may be used in any combination and ratio. Further, it may be used in a cured form together with a curing agent. Of these, alcohol-soluble copolymerized polyamides, modified polyamides and the like are preferable because they exhibit good dispersibility and coatability. The ratio of the inorganic particles used to the binder resin used for the undercoat layer can be arbitrarily selected, but from the viewpoint of the stability and coatability of the dispersion, it is usually 10% by mass or more with respect to the binder resin. It is preferable to use it in the range of 500% by mass or less.

<Photosensitive layer>
The types of photosensitive layers include a single-layer type in which a charge generating substance and a charge transporting substance are present in the same layer and are dispersed in a binder resin, and a charge generating layer and charges in which a charge generating substance is dispersed in a binder resin. A function-separated type (laminated type) consisting of two layers of charge transport layers in which the transport substance is dispersed in the binder resin can be mentioned, but any type may be used. The laminated photosensitive layer includes a forward-laminated photosensitive layer in which a charge generating layer and a charge transporting layer are laminated in this order from the conductive support side, and a reverse lamination in which a charge transporting layer and a charge generating layer are laminated in this order. There is a type photosensitive layer, and any of them can be adopted, but a forward-laminated type photosensitive layer capable of exhibiting the most balanced photoconductivity is preferable.

[Charge generation layer-laminated type]
In the case of a laminated photoconductor (function-separated photoconductor), the charge generating layer is formed by binding a charge generating substance with a binder resin. The film thickness is usually in the range of 0.1 μm or more, preferably 0.15 μm or more, and usually 10 μm or less, preferably 0.6 μm or less.
Examples of the charge generating substance include inorganic photoconductive materials such as selenium and its alloys and cadmium sulfide, and organic photoconductive materials such as organic pigments. Organic photoconductive materials are preferable, and organic pigments are particularly preferable. Is preferable. Examples of the organic pigment include phthalocyanine pigment, azo pigment, dithioketopyrrolopyrrole pigment, squalene (squarylium) pigment, quinacridone pigment, indigo pigment, perylene pigment, polycyclic quinone pigment, anthanthrone pigment, benzimidazole pigment and the like. .. Among these, phthalocyanine pigments or azo pigments are particularly preferable. When an organic pigment is used as a charge generating substance, fine particles of these organic pigments are usually used in the form of a dispersed layer bonded with various binder resins.

When a metal-free phthalocyanine compound or a metal-containing phthalocyanine compound is used as the charge generating substance, a photoconductor having high sensitivity to laser light having a relatively long wavelength, for example, laser light having a wavelength near 780 nm can be obtained, and monoazo, When an azo pigment such as diazo or trisazo is used, it is sufficient for white light, laser light having a wavelength near 660 nm, or laser light having a relatively short wavelength, for example, a laser having a wavelength near 450 nm or 400 nm. A photoconductor having high sensitivity can be obtained.

When an organic pigment is used as the charge generating substance, a phthalocyanine pigment or an azo pigment is particularly preferable. Phthalocyanine pigments provide photoconductors with high sensitivity to relatively long wavelength laser light, and azo pigments have sufficient sensitivity to white light and relatively short wavelength laser light. , Each is excellent.
When a phthalocyanine pigment is used as a charge generating substance, specifically, metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum and other metals or their oxides, halides and water. Those having each crystal form of coordinated phthalocyanines such as oxides and alkoxides, phthalocyanine dimers using an oxygen atom or the like as a cross-linking atom, and the like are used. In particular, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), and D-type (also known as Y-type), which are highly sensitive crystal types. Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, hydroxyindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as V type, μ-oxo-gallium phthalocyanine dimer such as G type and I type, type II, etc. The μ-oxo-aluminum phthalocyanine dimer of

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

The phthalocyanine compound may be a single compound, or may be in a mixed or mixed crystal state. As the phthalocyanine compound or the mixed state that can be placed in the crystalline state here, a mixture of each component may be used later, or the phthalocyanine compound may be mixed in the production / processing steps of the phthalocyanine compound such as synthesis, pigmentation, and crystallization. It may be the one that caused the state. As such a treatment, an acid paste treatment, a grinding treatment, a solvent treatment and the like are known. In order to generate a mixed crystal state, as described in Japanese Patent Application Laid-Open No. 10-48859, two types of crystals are mixed, mechanically ground, irregularized, and then converted to a specific crystal state by solvent treatment. There is a way to do it.

The binder resin used for the charge generation layer is not particularly limited, and examples thereof include polyvinyl butyral resin, polyvinyl formal resin, and polyvinyl acetal-based resins such as partially acetalized polyvinyl butyral resin in which a part of butyral is modified with formal or acetal. Resin, polyarylate resin, polycarbonate resin, polyester resin, modified ether-based polyester resin, phenoxy resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polystyrene resin, acrylic resin, methacrylic resin, polyacrylamide resin, polyamide Resin, polyvinylpyridine resin, cellulose resin, polyurethane resin, epoxy resin, silicon resin, polyvinyl alcohol resin, polyvinylpyrrolidone resin, casein, vinyl chloride-vinyl acetate copolymer, hydroxy-modified vinyl chloride-vinyl acetate copolymer, Vinyl chloride-vinyl acetate copolymers such as carboxyl-modified vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, Examples thereof include insulating resins such as styrene-alkyd resin, silicon-alkyd resin and phenol-formaldehyde resin, and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylperylene. Any one of these binder resins may be used alone, or two or more of these binder resins may be mixed and used in any combination.

In the charge generating layer, the blending ratio (mass) of the binder resin and the charge generating substance is such that the charge generating substance is usually 10 parts by mass or more, preferably 30 parts by mass or more, and usually 1000 parts by mass with respect to 100 parts by mass of the binder resin. It is in the range of parts or less, preferably 500 parts by mass or less.

[Charge transport layer-laminated type]
The charge transport layer of the laminated photoconductor contains a charge transport material, and usually contains a binder resin and other components used as needed. The charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different constituents or composition ratios. The film thickness is usually 5 μm to 50 μm, preferably 10 μm to 45 μm.

The charge transporting substance is not particularly limited, and any substance can be used. Examples of charge transporting substances include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron-withdrawing substances such as quinone compounds such as diphenoquinone, carbazole derivatives, and indols. Derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazol derivatives, benzofuran derivatives and other heterocyclic compounds, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stillben derivatives, butadiene derivatives, enamin derivatives and multiple types of these compounds are combined. Examples thereof include electron-donating substances such as polymers having a group composed of these compounds in the main chain or side chain. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and those in which a plurality of types of these compounds are bound are preferable. These charge transport materials may be used alone or in combination of several. Specific examples of suitable structures of the charge transport material are shown below.

Among the above charge transporting substances, preferably selected from the group consisting of HTM6, HTM10, HTM25, HTM26, HTM29, HTM31, HTM32, HTM33, HTM34, HTM35, HTM37, HTM39, HTM40, HTM41, HTM42, HTM43 and HTM44. It is at least one kind, and more preferably at least one kind selected from the group consisting of HTM6, HTM26, HTM29, HTM34, HTM39, HTM40, HTM41, HTM42, HTM43 and HTM44. The above-mentioned charge-transporting substance is preferable because good electrical characteristics can be obtained even when the polyester resin of the present invention is used.

The polycarbonate resin is preferably used as a binder resin for the charge transport layer. The binder resin may be a mixture of the polycarbonate resin and a resin having another structure, and examples of the other resin include those described in the resin having another structure mixed in the photosensitive layer.
As for the ratio of the polycarbonate resin to the charge transporting substance, the charge transporting substance is used at a ratio of 30 parts by mass or more with respect to 100 parts by mass of the polycarbonate resin. From the viewpoint of electrical characteristics, it is preferably 40 parts by mass or more. From the viewpoint of wear resistance, it is 200 parts by mass or less, preferably 150 parts by mass or less.

As the ratio of the entire binder resin to the charge transporting substance, the charge transporting substance is usually used at a ratio of 10 parts by mass or more with respect to 100 parts by mass of the binder resin in the same layer. Above all, 20 parts by mass or more is preferable from the viewpoint of reducing the residual potential, and 30 parts by mass or more is more preferable from the viewpoint of stability and charge mobility during repeated use. On the other hand, usually, the charge transporting substance is used in a ratio of 150 parts by mass or less and 120 parts by mass or less from the viewpoint of thermal stability of the photosensitive layer. Among them, 100 parts by mass or less is preferable from the viewpoint of compatibility between the charge transport substance and the binder resin, 80 parts by mass or less is more preferable from the viewpoint of abrasion resistance, and 70 parts by mass or less is particularly preferable from the viewpoint of scratch resistance.

The charge transport layer has a well-known plasticizer, antioxidant, ultraviolet absorber, and electron attraction in order to improve film forming property, flexibility, coating property, stain resistance, gas resistance, light resistance, and the like. Additives such as compounds, dyes, pigments and leveling agents may be included. Examples of plasticizers include hydrocarbon compounds, ester compounds, ether compounds, thioether compounds and the like. From the viewpoint of electrical properties, hydrocarbon compounds, ester compounds and ether compounds are preferable, and hydrocarbon compounds and ether compounds are more preferable. The plasticizer preferably has an aromatic group from the viewpoint of compatibility with the binder resin.

The molecular weight of the plasticizer is preferably 150 or more, more preferably 170 or more, further preferably 200 or more, while preferably 400 or less, more preferably 380 or less, still more preferably 350 or less. By setting the molecular weight within the above range, it is possible to improve crack resistance and gas resistance by blending with the binder resin while suppressing sublimation during film formation / drying.

These plasticizers may be used alone or in combination of several. Specific examples of suitable structures of the plasticizer are shown below.

Among these plasticizers, AD-2, AD-4, AD-5, AD-6, AD-8, AD-10, AD-11, and AD-13 are preferable, and AD-2 is more preferable. , AD-6, AD-8, AD-10, AD-11, AD-13. With the above-mentioned plasticizer, gas resistance and crack resistance can be improved without deteriorating the electrical characteristics.
Examples of the antioxidant include hindered phenol compounds, hindered amine compounds, trialkylamines, dialkylarylamines and the like. Examples of dyes and pigments include various dye compounds and azo compounds.

Examples of antioxidants include hindered phenol compounds, hindered amine compounds, trialkylamines, dialkylarylamines, thioether compounds and the like. From the viewpoint of electrical characteristics, hindered phenol compounds and trialkylamines are preferable.
These antioxidants may be used alone or in combination of several. Specific examples of suitable structures of antioxidants are shown below.

Among these antioxidants, AO-1, AO-2, AO-3, AO-6, AO-7, AO-8 are preferable, and AO-1, AO-2, AO- are more preferable. 3, AO-7. With the above-mentioned antioxidant, the antioxidant function can be maintained without deteriorating the electrical characteristics even after repeated use.
Examples of dyes and pigments include various dye compounds and azo compounds.

The charge transport layer includes inorganic particles such as alumina and silica, and fluororesin particles for the purpose of reducing frictional resistance and abrasion on the surface of the photoconductor and increasing the transfer efficiency of toner from the photoconductor to the transfer belt and paper. Organic particles such as silicone particles, polyethylene particles, crosslinked polystyrene particles, and crosslinked (meth) acrylate particles may be contained.

<Single layer type photosensitive layer>
The single-layer type photosensitive layer is formed by using a binder resin in order to secure the film strength, similarly to the charge transport layer of the laminated photoconductor, in addition to the charge generating substance and the charge transporting substance. Specifically, a charge generating substance, a charge transporting substance, and various binder resins are dissolved or dispersed in a solvent to prepare a coating liquid, which is placed on a conductive support (on the undercoat layer when an undercoat layer is provided). It can be obtained by coating and drying.

The types of the charge-transporting substance and the binder resin and the ratio of their use are the same as those described for the charge-transporting layer of the laminated photoconductor. The charge generating substance is further dispersed in the charge transporting medium composed of these charge transporting substances and the binder resin.
As the charge generating substance, a substance similar to that described for the charge generating layer of the laminated photoconductor can be used. However, in the case of the photosensitive layer of the single-layer type photoconductor, it is necessary to sufficiently reduce the particle size of the charge generating substance. Specifically, the range is usually 1 μm or less, preferably 0.5 μm or less.

If the amount of the charge generating substance dispersed in the single-layer photosensitive layer is too small, sufficient sensitivity cannot be obtained, but if it is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. It is usually used in the range of 0.5% by mass or more, preferably 1% by mass or more, and usually 50% by mass or less, preferably 20% by mass or less with respect to the entire layered photosensitive layer.
The ratio of the binder resin to the charge generating substance in the single-layer photosensitive layer is such that the charge generating substance is usually 0.1 part by mass or more, preferably 1 part by mass or more, and usually 100 parts by mass of the binder resin. It is 30 parts by mass or less, preferably 10 parts by mass or less.

The film thickness of the single-layer photosensitive layer is usually in the range of 5 μm or more, preferably 10 μm or more, and usually 100 μm or less, preferably 50 μm or less. In this case as well, known plasticizers for improving film formation property, flexibility, mechanical strength, etc., additives for suppressing residual potential, dispersion aids for improving dispersion stability, and coatability are used. Leveling agents, surfactants, for example, plasticizer oils, fluorine-based oils and other additives for improvement may be added.

<Other functional layers>
For both the laminated photoconductor and the single-layer photoconductor, the photosensitive layer or each layer constituting the photosensitive layer is provided with the purpose of improving film forming property, flexibility, coating property, stain resistance, gas resistance, light resistance, etc. , Well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, visible light shading agents and the like may be contained. In addition, for the purpose of reducing frictional resistance and wear on the surface of the photoconductor, and increasing the efficiency of transfer of toner from the photoconductor to the transfer belt and paper, a fluororesin, silicon resin, polyethylene resin, etc., or these are used on the surface layer. The surface layer may contain particles made of the above resin or particles of an inorganic compound. Alternatively, a layer containing these resins and particles may be newly formed as a surface layer. Further, if necessary, a barrier layer, an adhesive layer, an intermediate layer such as a blocking layer, a transparent insulating layer, or the like may have a layer for improving electrical characteristics and mechanical characteristics.

<Formation method of each layer>
For each layer constituting these photoconductors, a coating liquid obtained by dissolving or dispersing a substance to be contained in a solvent is dipped-coated, spray-coated, nozzle-coated, bar-coated, roll-coated, blade-coated, etc. on a support. It is formed by sequentially repeating the coating and drying steps for each layer by the known method of.

The solvent or dispersion medium used to prepare the coating liquid is not particularly limited, and specific examples thereof include alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, dimethoxyethane and the like. Ethers, esters such as methyl formate, ethyl acetate, ketones such as acetone, methyl ethyl ketone, cyclohexanone, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, chloroform, 1,2-dichloroethane, 1,1, Chlorinated hydrocarbons such as 2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine, triethylenediamine, etc. Examples thereof include nitrogen-containing compounds, aprotonic polar solvents such as acetonitrile, N-methylpyrrolidone, N, N-dimethylformamide, and dimethylsulfoxide. Among these solvents, non-halogen solvents are preferable from the viewpoint of environmental consideration, and toluene, xylene, anisole, dimethoxyethane, tetrahydrofuran, and 1,4-dioxane are particularly preferable from the viewpoint of solubility. Any one of these may be used alone, or two or more thereof may be used in combination.

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

In the case of the charge generation layer of the laminated photoconductor, the solid content concentration of the coating liquid is usually 0.1% by mass or more, preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. The range is% or less. The viscosity of the coating liquid is usually 0.01 cps or more, preferably 0.1 cps or more, and usually 20 cps or less, preferably 10 cps or less.
Examples of the coating method of the coating liquid include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, a curtain coating method and the like. , Other known coating methods can also be used.
The coating liquid is preferably dried by touch at room temperature and then heated and dried at rest or in a blast for 1 minute to 2 hours in a temperature range of 30 ° C. or higher and 200 ° C. or lower. Further, the heating temperature may be constant, and heating may be performed while changing the temperature during drying.

<Image forming device>
Next, an embodiment of an image forming apparatus (image forming apparatus of the present invention) using the electrophotographic photosensitive member of the present invention will be described with reference to FIG. 1 showing a main configuration of the apparatus. However, the embodiment is not limited to the following description, and can be arbitrarily modified and implemented as long as it does not deviate from the gist of the present invention.

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

In addition, the electrophotographic photosensitive member 1 is combined with one or two 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, and an integrated cartridge ( Hereinafter, it may be appropriately configured as an “electrophotographic photosensitive member cartridge”), and the electrophotographic photosensitive member cartridge may be configured to be removable from the main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. In this case, for example, when the electrophotographic photosensitive member 1 or other members deteriorate, the electrophotographic photosensitive member cartridge is removed from the image forming apparatus main body, and another new electrophotographic photosensitive member cartridge is attached to the image forming apparatus main body. This facilitates maintenance and management of the image forming apparatus.

Hereinafter, specific embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples as long as the gist of the present invention is not exceeded.

[Manufacturing of oligomers]
<Production Example 1> Preparation of oligomer solution 1 Under a nitrogen atmosphere, in a dissolution tank with stirring, desalinated water (27.75 kg), 25 mass% sodium hydroxide aqueous solution (3.58 kg), hydrosulfite sodium (2.26 g). ), 1,1-Bis (4-hydroxyphenyl) cyclohexane (2.0 kg) was added and uniformly dissolved (hereinafter referred to as an alkaline solution). Continuous-flow stirred tank reactor (CSTR reaction vessel, continuous-flow stirred tank reactor) equipped with three stepped reaction tanks (each reaction tank with internal volumes of 1.8L, 1.8L, and 4.5L). Was continuously added under the following conditions, and the reaction was carried out for a predetermined time. The liquid after the reaction was allowed to stand and separated into an organic phase and an aqueous phase to obtain an oligomer solution 1 which is an organic phase.

First reaction tank (internal temperature 35 ° C)
-The above alkaline aqueous solution (8835 ml / hour)
Dichloromethane (2276 mL / hour)
・ Gaseous phosgene (6.4 g / min)
Second reaction tank (internal temperature 30 ° C)
16 mass% p-tert-butylphenol in dichloromethane (17.3 ml / hour)
The analytical values of the oligomer solution 1 are as follows.
-Oligomer concentration (measured by evaporating to dryness): 22.5% by mass
-Terminal chloroformate group concentration (measured by diluting the oligomer solution with dichloromethane, adding aniline and pure water, and titrating with a 0.2N aqueous sodium hydroxide solution using phenolphthalein as an indicator): 0.44 Specified ・ Terminal phenolic hydroxyl group concentration (after diluting the oligomer solution with dichloromethane, titanium tetrachloride and acetic acid solution were added to develop color, and the absorbance was measured at a wavelength of 546 nm using a spectrophotometer): 0.01 Specified or less

Production Example 2 (Production of Polycarbonate Resin (1))
Oligomer solution 1 (302.57 g), 4-hydroxybenzoic acid 4-hydroxyphenyl (9.66 g) and dichloromethane (100 ml) prepared in Production Example 1 were weighed and stirred in a nitrogen-substituted 500 mL 4-port reaction vessel. .. Subsequently, a mixed solution of triethylamine (8.49 g) and dichloromethane (50 mL) was added dropwise to a reaction vessel cooled to 5 to 15 ° C. over 20 minutes. After continuing stirring for 30 minutes, the mixture was diluted with dichloromethane (80 ml), followed by acid washing twice with 0.2N hydrochloric acid aqueous solution (380 mL), and further washing with demineralized water (380 mL).

Separately, an alkaline aqueous solution prepared by dissolving sodium hydroxide (3.54 g) in desalinated water (380 ml) was transferred to a 2000 mL reaction vessel, and triethylamine (0.15 g) was added. The above dichloromethane solution was added to the place where the outside temperature of the reaction vessel was maintained at 14 ° C. and the mixture was stirred. After stirring for 1 hour, dilution was carried out with dichloromethane (190 mL), then stirring was continued for 2 hours, and dilution was carried out again with dichloromethane (150 mL). The organic layer was separated after the stirring was stopped and the mixture was allowed to stand for 30 minutes. The organic layer was washed with 0.1N hydrochloric acid (680 mL) three times, and further washed with demineralized water (680 mL) twice.

Dichloromethane (650 ml) was added to the washed organic layer to dilute it, and the precipitate obtained by pouring into methanol (8000 ml) was taken out by filtration and dried to obtain the desired polycarbonate resin (1). The viscosity average molecular weight (Mv) of the obtained polycarbonate resin was 54,300.

[Measurement of viscosity average molecular weight (Mv)]
A polyester resin was dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. The flow time t of the sample solution was measured in a constant temperature water bath set at 20.0 ° C. using an Ubbelohde type capillary viscometer having a solvent (dichloromethane) flow time t _{0 of 136.16 seconds.} The viscosity average molecular weight (Mv) was calculated according to the following formula.
a = 0.438 × η _sp +1 η _sp = t / t ₀ -1
b = 100 × η _sp / CC = 6.00 (g / L)
η = b / a
Mv = 3207 × η ^1.205

<Preparation of photoconductor sheet>
[Example 1]
10 parts by mass of oxytitanium phthalocyanine and 150 parts by mass of 4-methoxy-4-methyl-2-pentanone were mixed and subjected to pulverization and dispersion treatment with a sand grind mill to produce a pigment dispersion liquid. Oxytitanium phthalocyanine has a Bragg angle (2θ ± 0.2) of 9.3 °, 10.6 °, 13.2 °, 15.1 °, 15.7 °, 16. It shows strong diffraction peaks at 1 °, 20.8 °, 23.3 °, 26.3 °, and 27.1 °.

To this pigment dispersion, 50 parts by mass of a 5 mass% 1,2-dimethoxyethane solution of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name Denka Butyral # 6000C), phenoxy resin (manufactured by Union Carbide Co., Ltd., trade name) 50 parts by mass of a 5 mass% 1,2-dimethoxyethane solution of PKHH) was mixed, and 1,2-dimethoxyethane was further added to prepare a coating solution for forming a charge generation layer having a solid content concentration of 4.0%. This coating liquid for forming a charge generating layer was applied onto a polyethylene terephthalate sheet on which aluminum was vapor-deposited on the surface so that the film thickness after drying was 0.4 μm, and dried to provide a charge generating layer.

Next, as the charge transporting substance, a mixture (HTM39) produced by the method described in Example 1 of JP-A-2002-08432, which comprises a group of geometric isomer compounds having the structure shown below as a main component, is prepared. 50 parts by mass, 100 parts by mass of the polycarbonate resin (1) produced in Production Example 2, 8 parts by mass of an antioxidant (AO-2, trade name Irganox 1076), 0.05 parts by mass of silicone oil as a leveling agent. A coating solution for forming a charge transport layer was prepared by mixing with 640 parts by mass of a mixed solvent of tetrahydrofuran and toluene (80% by mass of tetrahydrofuran, 20% by mass of toluene).

This coating liquid for forming a charge transport layer is applied onto the above-mentioned charge generation layer using an applicator so that the film thickness after drying is 25 μm, and dried at 125 ° C. for 20 minutes to form a charge transport layer. , A photoconductor sheet was prepared.

[Comparative Example 1]
A photoconductor sheet was prepared in the same manner as in Example 1 except that the polycarbonate resin (1) was changed to the polycarbonate resin (2) (viscosity average molecular weight 40,000) shown below.

[Comparative Example 2]
A photoconductor sheet was prepared in the same manner as in Example 1 except that the polycarbonate resin (1) was changed to the polycarbonate resin (3) (viscosity average molecular weight 52,000) shown below.

[Evaluation of electrical characteristics]
Using an electrophotographic property evaluation device manufactured according to the measurement standards of the Electrophotographic Society (continued: Basics and Applications of Electrophotographic Technology, edited by the Electrophotographic Society, Corona, pp. 404-405), the photoconductor was placed on an aluminum drum. After affixing it into a cylindrical shape and establishing continuity between the aluminum drum and the aluminum substrate of the photoconductor, the drum is rotated at a constant rotation speed, and an electrical characteristic evaluation test is performed by a cycle of charging, exposure, potential measurement, and static elimination. went. At that time, the initial surface potential is set to -700.
The surface potential (VL) at the time of irradiation with ^{exposure light of 2.4 μJ / cm 2} was measured using monochromatic light of 780 nm for exposure and 660 nm for static elimination. In the VL measurement, the time required from the exposure to the potential measurement was set to 139 ms. ^{Further, the irradiation energy (half exposure energy: μJ / cm 2} ) when the surface potential became half of the initial surface potential (-350 V) was measured as the sensitivity (E _1/2). The smaller the absolute value of the VL value, the better the electrical characteristics, and the smaller the value of E _1/2 , the higher the sensitivity. The measurement environment was performed at a temperature of 25 ° C. and a relative humidity of 50% (N / N). The results are shown in Table-1.

[Abrasion test]
The photoconductor film was cut into a circle with a diameter of 10 cm and evaluated for wear by a tabor wear tester (manufactured by Toyo Seiki Co., Ltd.). The test conditions were measured by comparing the mass before and after the test with the amount of wear after 1000 rotations under a load of 500 g using a wear wheel CS-10F in an atmosphere of 25 ° C. and 50% RH. The smaller the value, the better the wear resistance. The results are shown in Table-1.

<Creation of electrophotographic photosensitive member>
<Manufacturing of coating liquid for forming undercoat layer>
A rutile-type titanium oxide having an average primary particle diameter of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) in an amount of 3% by mass based on the titanium oxide are used in a Henshell mixer. 1 kg of a raw material slurry obtained by mixing 50 parts of surface-treated titanium oxide obtained by mixing and 120 parts of methanol is used as a dispersion medium of zirconia beads (YTZ manufactured by Nikkato Co., Ltd.) having a diameter of about 100 μm, and the mill volume is about 0. A titanium oxide dispersion was prepared by using a .15 L ultra-apex mill (UAM-015 type) manufactured by Kotobuki Kogyo Co., Ltd. for 1 hour in a liquid circulation state with a rotor peripheral speed of 10 m / sec and a liquid flow rate of 10 kg / hour. ..

Stir the titanium oxide dispersion, the mixed solvent of methanol / 1-propanol / toluene, and the pellets of the same polyamide resin used in the preparation of the dispersion for the undercoat layer at the time of preparing the photoconductor sheet while heating. After mixing to dissolve the polyamide pellets, ultrasonic dispersion treatment with an ultrasonic transmitter with an output of 1200 W is performed for 1 hour, and further filtration is performed with a PTFE membrane filter (Advantech Mitex LC) having a pore size of 5 μm, and surface treatment oxidation is performed. The mass ratio of titanium / copolymerized polyamide is 3/1, the mass ratio of the mixed solvent of methanol / 1-propanol / toluene is 7/1/2, and the concentration of the solid content contained is 18.0% by mass. A coating liquid for forming an undercoat layer was prepared.

<Manufacturing of coating liquid for forming charge generation layer>
As a charge generating substance, 20 parts of oxytitanium phthalocyanine and 280 parts of 1,2-dimethoxyethane, which show an X-ray diffraction spectrum by CuKα characteristic X-ray in FIG. 2, are mixed, and pulverized and dispersed by a sand grind mill for 1 hour. Processing was performed. Subsequently, 10 parts of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name "Denka butyral"# 6000C), 255 parts of 1,2-dimethoxyethane and 4-methoxy-4-methyl were added to this micronized treatment liquid. A binder solution obtained by dissolving in a mixed solution of 85 parts of -2-pentanone and 230 parts of 1,2-dimethoxyethane were mixed to prepare a coating solution A for forming a charge generation layer.

As a charge generating substance, 20 parts of oxytitanium phthalocyanine and 280 parts of 1,2-dimethoxyethane, which show an X-ray diffraction spectrum by CuKα characteristic X-ray in FIG. 3, are mixed, and pulverized and dispersed by a sand grind mill for 4 hours. Processing was performed. Subsequently, 10 parts of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name "Denka butyral"# 6000C), 255 parts of 1,2-dimethoxyethane and 4-methoxy-4-methyl were added to this micronized treatment liquid. A binder solution obtained by dissolving in a mixed solution of 85 parts of -2-pentanone and 230 parts of 1,2-dimethoxyethane were mixed to prepare a coating solution B for forming a charge generation layer.
The charge-generating layer-forming coating liquid A and the charge-generating layer-forming coating liquid B were mixed at a mass ratio of 55:45 to prepare the charge-generating layer-forming coating liquid used in this example.

<Manufacturing of coating liquid for forming charge transport layer>
[Coating liquid C1]
97.5 parts of the polycarbonate resin (1) produced in Production Example 2, 2.5 parts of the polyallylate resin (PA-1) having the repeating structure and the terminal structure shown below (viscosity average molecular weight 35,000, in the polymer) Polysiloxane structure content 12.5% by mass), 40 parts of charge transport material represented by HTM34 below, 10 parts of additive AD-13, antioxidant 2,6-di-tert-butyl-4- Dissolve 2 parts of methyl-phenol, 1 part of tribenzylamine, and 0.05 part of dimethylpolysiloxane (KF96-10CS manufactured by Shin-Etsu Chemical Co., Ltd.) in 650 parts of tetrahydrofuran / toluene (8/2 (mass ratio)) mixed solvent. A coating liquid C1 for forming a charge transport layer was prepared.

[Coating liquid C2]
The coating liquid C2 was prepared in the same manner as the coating liquid C1 except that the polyester resin (1) was changed to the polycarbonate resin (4) having the structure shown below in the coating liquid.

<Manufacturing of photoconductor drum>
A coating liquid for forming an undercoat layer and a coating liquid for forming a charge generation layer prepared in the production example of a coating liquid on a cylinder made of an aluminum alloy having an outer diameter of 24 mm, a length of 248 mm, and a wall thickness of 0.75 mm whose surface has been machined. , The coating liquid for forming the charge transport layer is sequentially applied and dried by the immersion coating method, and the undercoat layer, the charge generation layer, and the charge are adjusted so that the thicknesses after drying are 1.5 μm, 0.4 μm, and 36 μm, respectively. A transport layer was formed to produce a photoconductor drum. The charge transport layer was dried at 125 ° C. for 24 minutes.

<Image test>
The obtained photoconductor was mounted on a photoconductor cartridge of Samsung's monochrome printer M4580 (non-magnetic one-component non-contact development) at a temperature of 25 ° C. and a relative humidity of 50% at a printing rate of 5% and 400. Continuous printing of 000 sheets was performed. The film thickness of the charge transport layer after printing was measured, and the amount of film loss was confirmed by comparing the film thickness of the charge transport layer before and after printing, and the printing durability was evaluated. The smaller the value, the better the wear resistance.

[Example 2, Comparative Example 3]
The photoconductor drums shown in Table 2 were prepared, and the printing resistance and electrophotographic photosensitive member were evaluated. The results are shown in Table-2.

From the above, it has been clarified that the electrophotographic photosensitive member containing the specific polycarbonate resin of the present invention is not only excellent in electrical characteristics but also extremely excellent in abrasion resistance.

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

Claims (6)

An electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive layer is represented by the following formula (1).
) And the polycarbonate resin containing the repeating unit represented by the following formula (2), the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2). The ratio of the repeating unit represented by the above formula (1) to the total of 1 mol% or more and 50 m
An electrophotographic photosensitive member having an ol% or less and a content of the repeating unit represented by the formula (2) in the polycarbonate resin of 50 mol% or more and 99 mol% or less.

(In the formula (1), Ar ¹ and Ar ² represent an arylene group which may independently have a substituent. Z ¹ is a divalent group having an aromatic group, and s is 0. Or an integer of 1.)

(In the formula (2), R ¹ and R ² independently represent any one of a hydrogen atom, a halogen group, a hydrocarbon group, and an alkoxy group, and the hydrocarbon group and the alkoxy group are some or all hydrogen. Atoms may be substituted with halogen groups. X ¹ represents a single bond, —CR ³ R ⁴ −, CO, or S, and R ³ and R ⁴ are independent hydrogen atoms, halogen groups, respectively. Representing either a hydrocarbon group or an alkoxy group, the hydrocarbon group and the alkoxy group may have some or all hydrogen atoms substituted with halogen groups, and R ³ and R ⁴ may be mutually exclusive. They may be combined to form a ring. M ¹ and m ² independently represent integers of 0 or more and 4 or less.) Repeating unit represented by the formula (1) is a repeating unit or the following represented by the following formula (3)
The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is a repeating unit represented by the formula (4).

In the formula (3), R ⁵ and R ⁶ independently represent any one of a hydrogen atom, a halogen group, an alkyl group, and an alkoxy group, and some or all of the hydrogen atoms of the alkyl group and the alkoxy group are halogen. It may be substituted with a group. m ³ and m ⁴ independently represent integers of 0 or more and 4 or less.

In formula (4), Ar ³ represents an arylene group which may have a substituent. R ⁷ and R ⁸ each independently represent one of a hydrogen atom, a halogen group, an alkyl group, and an alkoxy group, and the alkyl group and the alkoxy group have some or all hydrogen atoms substituted with halogen groups. May be good. m ⁵ and m ⁶ independently represent integers of 0 or more and 4 or less. The electrophotographic photosensitive member according to claim 1 or 2, a charging means for charging the electrophotographic photosensitive member, and an image exposure means for forming an electrostatic latent image by performing image exposure on the charged electrophotographic photosensitive member. An electrophotographic cartridge comprising at least one of a developing means for developing the electrostatic latent image with toner and a transfer means for transferring the toner to an object to be transferred. The electrophotographic photosensitive member according to claim 1 or 2, a charging means for charging the electrophotographic photosensitive member, an exposure means for forming an electrostatic latent image by exposure to the charged electrophotographic photosensitive member, and the electrostatic. It is characterized by including a developing means for developing a latent image with toner, a transfer means for transferring the toner to a transfer target, and a fixing means for fixing the toner transferred to the transfer target.
Image forming device. The method for producing a polycarbonate resin contained in the photosensitive layer of an electrophotographic photosensitive member according to claim 1 or 2, wherein the production process includes solution polymerization and interfacial polymerization, and an oligomer is produced by solution polymerization, followed by an interface. A port characterized by producing a polycarbonate resin by polymerization.
A method for producing a carbonate resin. A method for producing a polycarbonate resin containing a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), wherein the manufacturing process of the polycarbonate resin includes solution polymerization and interfacial polymerization. A method for producing a polycarbonate resin, which comprises producing an oligomer by solution polymerization and then producing a polycarbonate resin by interfacial polymerization.

(In the formula (1), Ar ¹ and Ar ² represent an arylene group which may independently have a substituent. Z ¹ is a divalent group having an aromatic group, and s is 0. Or an integer of 1.)

(In the formula (2), R ¹ and R ² independently represent any one of a hydrogen atom, a halogen group, a hydrocarbon group, and an alkoxy group, and the hydrocarbon group and the alkoxy group are a part or all of hydrogen. atoms may be substituted with a halogen group .X ¹ is a single ^{bond, -CR 3 R 4 -, O} , CO
, Or S. Further, R ³ and R ⁴ independently represent any one of a hydrogen atom, a halogen group, a hydrocarbon group, and an alkoxy group, and in the hydrocarbon group and the alkoxy group, a part or all of the hydrogen atoms are replaced with a halogen group. It may have been. Further, R ³ and R ⁴ may be coupled to each other to form a ring. m ¹ and m ² independently represent integers of 0 or more and 4 or less.
)

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