JP4862663B2 - Electrophotographic photosensitive member, image forming apparatus using the same, and electrophotographic cartridge - Google Patents

Description

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

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

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

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

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

  In the case of a general photoreceptor having no functional layer such as a surface protective layer, it is the photosensitive layer that receives such a load. The photosensitive layer is usually composed of a binder resin and a photoconductive substance, and the binder resin substantially determines the strength. However, since the doping amount of the photoconductive substance is considerably large, the conventional technology has not yet provided the photosensitive layer with sufficient mechanical strength.

  Examples of the binder resin of the photosensitive layer include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resins, and various types. The thermosetting resin is used. Among the various binder resins, the polycarbonate resin has a relatively excellent performance, and various polycarbonate resins have been developed and put into practical use (see, for example, Patent Documents 1 to 4).

On the other hand, a technique of an electrophotographic photoreceptor using a polyarylate resin marketed under the trade name “U-polymer” as a binder resin is disclosed, and among them, the sensitivity is particularly superior to that of polycarbonate. (For example, refer to Patent Document 5).
Also disclosed is a technique for an electrophotographic photoreceptor using a polyarylate resin using a dihydric phenol component having a specific structure as a binder resin, improving the solution stability during the production of the photoreceptor, mechanical strength, It is known that the wear resistance is excellent (see, for example, Patent Documents 6 and 7).

JP 50-98332 A JP 59-71057 A JP 59-184251 JP-A-5-21478 JP-A-56-135844 Japanese Patent Laid-Open No. 3-6567 Japanese Patent Laid-Open No. 10-288845

  However, conventional photoreceptors may be worn or scratched due to practical loads such as friction caused by toner developer, transfer member, paper, cleaning member (blade), etc. It has problems such as. For this reason, the present situation is that the printing performance is limited in practical use.

  The present invention has been made to solve such problems. That is, an object of the present invention is to provide an electrophotographic photoreceptor excellent in wear resistance, and an image forming apparatus and an electrophotographic cartridge using the electrophotographic photoreceptor.

  As a result of intensive studies, the present inventors have found that an excellent machine can be obtained by using a polyester resin having a specific repeating structure in the photosensitive layer and a polyester resin and / or a polycarbonate resin having a repeating structure different from the polyester resin. The present invention has been completed as a result of the finding that a high durability is obtained.

（前記式（１）中、Ａｒ¹〜Ａｒ⁴は、それぞれ独立に、置換基を有していてもよいアリーレン基を表わし、Ｘ¹は単結合または二価基を表わす。）

That is, the gist of the present invention is that, in an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive layer includes a polyester resin (first resin) containing a repeating structure represented by the following formula (1): And a polycarbonate resin (second resin), and at least the second resin includes a repeating structure represented by the following formula (2). 1).

(In the formula (1), Ar ^{1 to} Ar ⁴ each independently represents an arylene group which may have a substituent, and X ¹ represents a single bond or a divalent group.)

また、前記の電子写真感光体は、波長３８０〜５００ｎｍの単色書き込み光で使用されるものであることが好ましい（請求項３）。 In this case, it is preferred that the second resin is a polycarbonate resin containing a repeating structural 70 wt% or more of the following formula (2 ') (claim 2).

Further, the electrophotographic photoreceptor of the is preferably intended to be used with monochromatic writing light of wavelength 380 to 500 nm (claim 3).

Another gist of the present invention is an image exposure for forming an electrostatic latent image by performing image exposure on the electrophotographic photosensitive member and the charging means for charging the electrophotographic photosensitive member. means, a developing means for developing the electrostatic latent image with toner, characterized by comprising a transfer means for transferring the toner to a transfer object, it resides in an image forming apparatus (claim 4).
In this case, said image exposure light is preferably a monochromatic light having an exposure wavelength 380~500nm and performs exposure (claim 5).

Still another subject matter of the present invention is the above-described electrophotographic photosensitive member, charging means for charging the electrophotographic photosensitive member, and image exposure for performing image exposure on the charged electrophotographic photosensitive member to form an electrostatic latent image. means, developing means for developing the electrostatic latent image with toner, and among the transfer means for transferring the toner to a transfer object, characterized in that it comprises at least one, consists in an electrophotographic cartridge (claim 6 ).

  According to the present invention, an electrophotographic photoreceptor excellent in abrasion resistance, and an image forming apparatus and an electrophotographic cartridge using the electrophotographic photoreceptor can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented by being arbitrarily modified within the scope of the gist thereof.

[I. Electrophotographic photoreceptor]
The electrophotographic photosensitive member (photosensitive member) of the present invention has a photosensitive layer on a conductive support. In addition, the photosensitive layer includes a polyester resin having a specific repeating structure (hereinafter, referred to as “first resin” as appropriate) and a polyester resin having a structure different from that of the polyester resin (that is, the first resin). And at least one resin selected from the group of polycarbonate resins (hereinafter referred to as “second resin” as appropriate). These first resin and second resin normally function as a binder resin in the photosensitive layer.

[I-1. Binder resin]
The photoreceptor of the present invention contains a first resin and a second resin in the photosensitive layer. Specifically, when the photosensitive layer is composed of a single layer, the photosensitive layer contains the first resin and the second resin, and when the photosensitive layer is composed of two or more layers, One or more layers contain a first resin and a second resin. Further, the layer containing the first resin and the second resin may contain a resin other than the first resin and the second resin.

（前記式（１）中、Ａｒ¹〜Ａｒ⁴は、それぞれ独立に、置換基を有していてもよいアリーレン基を表わし、Ｘ¹は単結合または二価基を表わす。） [I-1-1. First resin]
The first resin contained in the photosensitive layer of the photoreceptor of the present invention is a polyester resin including a repeating structure represented by the following formula (1).

(In the formula (1), Ar ^{1 to} Ar ⁴ each independently represents an arylene group which may have a substituent, and X ¹ represents a single bond or a divalent group.)

In the formula (1), Ar ^{1 to} Ar ⁴ each independently represents an arylene group.
The carbon number of Ar ^{1 to} Ar ⁴ is arbitrary as long as the effects of the present invention are not significantly impaired. However, the carbon number of Ar ¹ and Ar ² is usually 6 or more, usually 20 or less, preferably 12 or less, particularly preferably 7. Ar ³ and Ar ⁴ usually have 6 or more carbon atoms, usually 20 or less, preferably 12 or less, and particularly preferably 6.

The number of rings Ar ^{1 to} Ar ⁴ is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 1 or more, usually 3 or less, preferably 2 or less, and particularly preferably 1.

Specific examples of Ar ^{1 to} Ar ⁴ include a phenylene group, a naphthylene group, a 3-methylphenylene group, and a 3-phenylphenylene group. In addition, examples include an anthrylene group, a phenanthrylene group, a pyrenylene group, and the like. Among these, a phenylene group and a naphthylene group are particularly preferable from the viewpoint of production cost. Further, when a phenylene group and a naphthylene group are compared, a phenylene group is more preferable in terms of ease of synthesis in addition to manufacturing cost.

Moreover, the arylene group which comprises Ar < ¹ > -Ar < ⁴ > may have a substituent each independently. Specific examples of the substituent include an alkyl group, an aryl group, a halogen group, an alkoxy group, and a condensed polycyclic group. Of these, considering the mechanical properties as a binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the aryl group is preferably a phenyl group, a naphthyl group, etc., and the halogen group is a fluorine atom, chlorine An atom, a bromine atom, an iodine atom and the like are preferable, and examples of the alkoxy group include a methoxy group, an ethoxy group and a butoxy group. In addition, when the substituent is an alkyl group, the carbon number of the alkyl group is usually 1 or more, and usually 10 or less, preferably 8 or less, more preferably 2 or less, and specifically, a methyl group is particularly preferred. . Moreover, there is no restriction | limiting in particular in the number of each substituent of Ar < ¹ > -Ar < ⁴ >, Preferably it is 3 or less, It is more preferable that it is 2 or less, It is especially preferable that it is 1 or less.

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

In the formula (1), X ¹ represents a single bond or a divalent group. Preferable examples of X ¹ include a sulfur atom, an oxygen atom, a sulfonyl group, a cycloalkylene group, —CR ² R ³ — and the like. Here, R ² and R ³ each independently represent a hydrogen atom, an alkyl group, an aryl group, a halogen group, or an alkoxy group. Of R ² and R ³ , the aryl group is preferably a phenyl group, a naphthyl group, etc., considering the mechanical properties as a binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer. As the halogen group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like are preferable, and as the alkoxy group, a methoxy group, an ethoxy group, a butoxy group and the like are preferably exemplified. When R ² or R ³ is an alkyl group, the alkyl group usually has 1 or more carbon atoms, usually 10 or less, preferably 8 or less, more preferably 2 or less.

Further, considering the simplicity of production of the divalent hydroxy compound used for producing the first resin, examples of preferable groups as X ¹ include —O—, —S—, —SO—, and —SO. _{2 -, - CO -, -} CH 2 -, - CH (CH 3) -, - C (CH 3) 2 -, include cyclohexylidene. Among these, —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ —, and cyclohexylidene are preferable, and —CH ₂ —, —CH (CH ₃ ) —, cyclohexylene are particularly preferable. Den.

（式（３），（４）において、Ａｒ¹〜Ａｒ⁴は、それぞれ独立に、置換基を有していてもよいアリーレン基を表わし、Ｘ¹は単結合または二価基を表わす。） By the way, the repeating structure represented by the above formula (1) is represented by a divalent hydroxy residue (partial structure represented by the following formula (3)) and a dicarboxylic acid residue (the following formula (4)). Partial structure). The structures of these divalent hydroxy residues and dicarboxylic acid residues have various effects on the first resin. Therefore, it is desirable that the structures of the divalent hydroxy residue and the dicarboxylic acid residue are appropriately preferred.

(In formulas (3) and (4), Ar ^{1 to} Ar ⁴ each independently represent an arylene group which may have a substituent, and X ¹ represents a single bond or a divalent group.)

Hereinafter, preferred structures of the above divalent hydroxy residue and dicarboxylic acid residue will be described.
First, the divalent hydroxy residue is represented by the formula (3). In the formula (3), Ar ¹ , Ar ² and X ¹ are the same as those described in the formula (1).

（式（５）中、Ａｒ⁵、Ａｒ⁶は、それぞれ独立に、置換基を有していてもよいフェニレン基を表わし、Ｒ¹は水素原子またはメチル基を表わす。） Among the divalent hydroxy residues represented by the above formula (3), a divalent phenol residue represented by the following formula (5) is particularly preferable.

(In Formula (5), Ar ⁵ and Ar ⁶ each independently represent a phenylene group which may have a substituent, and R ¹ represents a hydrogen atom or a methyl group.)

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

Specific examples of the formula (5) include divalent phenol residues having a structure in which a hydrogen atom is removed from the hydroxyl group of the divalent phenol compound exemplified below.
That is, when R ¹ is a hydrogen atom, examples of the dihydric phenol compound corresponding to the dihydric phenol residue represented by the formula (5) include bis (2-hydroxyphenyl) methane, (2-hydroxyphenyl). ) (3-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (3-hydroxyphenyl) methane, (3-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (4- Hydroxyphenyl) methane, bis (2-hydroxy-3-methylphenyl) methane, bis (2-hydroxy-3-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) ) Methane, (2-hydroxy-3-ethylphenyl) (3-hydroxy-4-ethylphenyl) Tan, (2-hydroxy-3-methylphenyl) (4-hydroxy-3-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, bis (3- Hydroxy-4-methylphenyl) methane, bis (3-hydroxy-4-ethylphenyl) methane, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) methane, (3-hydroxy-4 -Ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, bis (4-hydroxy-3-ethylphenyl) methane, bis (4-hydroxy-3, 5-dimethylphenyl) methane, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4 -Dimethylphenyl) methane, bis (3-hydroxy-2,4-dimethylphenyl) methane and the like.

When R ¹ is a methyl group, examples of the dihydric phenol compound corresponding to the dihydric phenol residue represented by the formula (5) include 1,1-bis (2-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (3-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane, 1,1-bis (3-hydroxyphenyl) ethane 1- (3-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (2-hydroxy-3-methylphenyl) ethane, 1,1-bis (2-hydroxy-3-ethylphenyl) ethane, 1- (2-hydroxy-3-methylphenyl) -1- (3-hydroxy-4-methylphenyl) ethane 1- (2-hydroxy-3-ethylphenyl) -1- (3-hydroxy-4-ethylphenyl) ethane, 1- (2-hydroxy-3-methylphenyl) -1- (4-hydroxy-3) -Methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (4-hydroxy-3-ethylphenyl) ethane, 1,1-bis (3-hydroxy-4-methylphenyl) ethane, 1,1-bis (3-hydroxy-4-ethylphenyl) ethane, 1- (3-hydroxy-4-methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (3-hydroxy -4-ethylphenyl) -1- (4-hydroxy-3-ethylphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 1,1-bis (4- Hydroxy-3-ethylphenyl) ethane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane, 1- (4-hydroxy-3,5-dimethylphenyl) -1- (3-hydroxy- 2,4-dimethylphenyl) ethane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) ethane and the like.

Among these, considering the simplicity of production of the dihydric phenol compound, when R ¹ is a hydrogen atom, bis (4-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, bis ( 2-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, bis (4-hydroxy-3-ethylphenyl) methane, bis (4-hydroxy-3,5-dimethylphenyl) methane are particularly preferred. . When R ¹ is a methyl group, 1,1-bis (4-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane, 1,1-bis ( 2-hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 1,1-bis (4-hydroxy-3-ethylphenyl) ethane, 1,1-bis (4-hydroxy) -3,5-dimethylphenyl) ethane is preferred.

  Further, in the formula (3), when an example of a divalent hydroxy residue not included in the formula (5) is given, divalent hydroxy having a structure in which a hydrogen atom is removed from the hydroxyl group of the divalent hydroxy compound exemplified below. Residue.

  That is, examples of the divalent hydroxy compound corresponding to the divalent hydroxy residue represented by the formula (3) include 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, 2 , 4,3 ′, 5′-tetramethyl-3,4′-dihydroxybiphenyl, 2,2 ′, 4,4′-tetramethyl-3,3′-dihydroxybiphenyl;

1,1-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2 -(4-hydroxy-3,5-dimethylphenyl) -2- (3-hydroxy-2,4-dimethylphenyl) propane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) propane, 2 , 2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2- (4-hydroxy-3,5-dimethylphenyl) -2- (3-hydroxy-2,4-dimethylphenyl) propane, 2,2-bis (3-hydroxy-2,4 Dimethylphenyl) propane;

Bis- (4-hydroxyphenyl) phenylmethane, 1,1-bis- (4-hydroxyphenyl) -1-phenylethane, 1,1-bis- (4-hydroxyphenyl) -1-phenylpropane, bis- ( 4-hydroxyphenyl) diphenylmethane, bis- (4-hydroxyphenyl) dibenzylmethane,

1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, -(4-hydroxy-3,5-dimethylphenyl) -1- (3-hydroxy-2,4-dimethylphenyl) cyclohexane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) cyclohexane;

Bis (2-hydroxyphenyl) ether, (2-hydroxyphenyl) (3-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (3-hydroxyphenyl) ether, (3-hydroxy Phenyl) (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ether, bis (2-hydroxy-3-methylphenyl) ether, bis (2-hydroxy-3-ethylphenyl) ether, (2-hydroxy- 3-methylphenyl) (3-hydroxy-4-methylphenyl) ether, (2-hydroxy-3-ethylphenyl) (3-hydroxy-4-ethylphenyl) ether, (2-hydroxy-3-methylphenyl) ( 4-hydroxy-3-methylphenyl) ether (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (3-hydroxy-4-methylphenyl) ether, bis (3-hydroxy-4-ethylphenyl) ether, (3 -Hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) ether, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxy-3- Methylphenyl) ether, bis (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) ether, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy- 2,4-dimethylphenyl) ether, bis (3-hydroxy-2,4-dimethylphenol Le) ether;

Bis (4-hydroxyphenyl) ketone, etc. are mentioned.

  Among these, considering the simplicity of production of the divalent hydroxy compound, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, 2,2-bis (4-hydroxy-3) , 5-dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, or bis (4-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) Ether, bis (2-hydroxyphenyl) ether, bis (4-hydroxy-3-methylphenyl) ether, bis (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) Ether is preferred.

  In addition, the bivalent hydroxy compound and divalent hydroxy residue mentioned above may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

On the other hand, the dicarboxylic acid residue is represented by the formula (4). In the formula (4), Ar ³ and Ar ⁴ are the same as those described in the formula (1). Specific examples of the dicarboxylic acid residue having the structure represented by the above formula (4) include dicarboxylic acid residues having a structure in which the hydroxyl group is removed from the carboxyl group of the dicarboxylic acid compound exemplified below.
That is, for example, examples of the dicarboxylic acid compound corresponding to the dicarboxylic acid residue represented by the formula (4) include diphenyl ether-2,2′-dicarboxylic acid, diphenyl ether-2,3′-dicarboxylic acid, diphenyl ether- Examples include 2,4′-dicarboxylic acid, diphenyl ether-3,3′-dicarboxylic acid, diphenyl ether-3,4′-dicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid. Among these, diphenyl ether-2,2′-dicarboxylic acid, diphenyl ether-2,4′-dicarboxylic acid, and diphenyl ether-4,4′-dicarboxylic acid are preferable, considering the simplicity of production of the dicarboxylic acid compound. -4,4'-dicarboxylic acid is particularly preferred.
In addition, the dicarboxylic acid compound and dicarboxylic acid residue mentioned above may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

（式（６）中、Ａｒ⁵〜Ａｒ⁸は、それぞれ独立に、置換基を有していてもよいフェニレン基を表わし、Ｒ¹は水素原子またはメチル基を表わす。） Therefore, it is preferable to appropriately select the aforementioned Ar ^{1 to} Ar ⁴ and X ¹ so that the structure of the divalent hydroxyl residue and the dicarboxylic acid residue is the preferable structure.
From the above points, among the polyester resins of the present invention described above, those including a repeating structure represented by the following formula (6) are particularly preferable.

(In formula (6), Ar ^{5 to} Ar ⁸ each independently represents a phenylene group which may have a substituent, and R ¹ represents a hydrogen atom or a methyl group.)

In the formula (6), Ar ⁵ , Ar ⁶ and R ¹ are the same as those described in the formula (5).
In the formula (6), Ar ⁷ and Ar ⁸ each independently represent a phenylene group which may have a substituent. At this time, the substituents of Ar ⁷ and Ar ⁸ are the same as those described above as the substituents of Ar ^{1 to} Ar ⁴ .
Moreover, the repeating structure represented by the formula (1) may be one type in the first resin, or two or more types may be used in any combination and ratio. Therefore, the above divalent hydroxy residue and dicarboxylic acid residue may be used alone or in combination of two or more in any combination and ratio. Ar ^{1 to} Ar ⁴ and X ¹ may each be used alone or in combination of two or more in any combination and ratio.

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

  However, in the first resin, it is preferable that the number of repeating units other than the divalent hydroxy residue represented by the formula (3) or the dicarboxylic acid residue represented by the formula (4) is small. Therefore, it is preferable that the amount of divalent hydroxy residues other than those represented by formula (3) and dicarboxylic acid residues other than those represented by formula (4) is also small. Although the specific ratio is not limited, for example, for the dicarboxylic acid residue, the ratio of the dicarboxylic acid residue represented by the formula (4) in the total amount of the dicarboxylic acid residue is usually 70 by the ratio of the number of repeating units. % Or more, preferably 80% or more, more preferably 90% or more, and particularly preferably 100%.

  Next, the manufacturing method of 1st resin is demonstrated. A known polymerization method can be used as a method for producing the first resin. Examples thereof include an interfacial polymerization method, a melt polymerization method, and a solution polymerization method.

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

  Examples of the alkali component used in the interfacial polymerization method include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. As the usage-amount of an alkali, the range of 1.01-3 times equivalent of the phenolic hydroxyl group contained in a reaction system is preferable.

  Examples of the halogenated hydrocarbon include dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, dichlorobenzene, and the like. In addition, a halogenated hydrocarbon may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

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

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

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

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

[I-1-2. Second resin]
The second resin is not particularly limited as long as it is at least one resin selected from the group consisting of a polyester resin and a polycarbonate resin, which has a structure different from that of the first resin, and is arbitrary as long as the effects of the present invention are not significantly impaired. Resin can be used. Therefore, a known polyester resin and polycarbonate resin can be used as the second resin. In the present invention, as the second resin, at least one of a polyester resin and a polycarbonate resin may be used, and therefore both the polyester resin and the polycarbonate resin can be used.

  Examples of the polycarbonate resin that can be used as the second resin include those having a structural unit derived from the following bifunctional phenol compound. That is, for example, as the bifunctional phenol compound, bis- (4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 1,1-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) butane, 2,2-bis- (4-hydroxyphenyl) pentane, 2,2-bis- (4 -Hydroxyphenyl) -3-methylbutane, 2,2-bis- (4-hydroxyphenyl) hexane, 2,2-bis- (4-hydroxyphenyl) -4-methylpentane, 1,1-bis- (4- Hydroxyphenyl) cyclopentane, 1,1-bis- (4-hydroxyphenyl) cyclohexane, bis- (4-hydroxy-3-methylphenyl) meta Bis- (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane, 2,2-bis- (4-hydroxy-3-methylphenyl) ) Propane, 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis- (4-hydroxy-3-ethylphenyl) propane, 2,2-bis- (4- Hydroxy-3-isopropylphenyl) propane, 2,2-bis- (4-hydroxy-3-sec-butylphenyl) propane, bis- (4-hydroxyphenyl) phenylmethane, 1,1-bis- (4-hydroxy) Phenyl) -1-phenylethane, 1,1-bis- (4-hydroxyphenyl) -1-phenylpropane, bis- (4-hydroxyphenyl) diphenyl Methane, bis- (4-hydroxyphenyl) dibenzylmethane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxydiphenyl sulfide, phenolphthalein, 5, 5 ′-( 1-methylethylidene) bis [1,1 ′-(biphenyl) -2-ol], [1,1′-biphenyl] -4,4′-diol, [1,1′-biphenyl] -3,3 ′ -Diol, 4,4'-oxybisphenol, bis (4-hydroxyphenyl) methanone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, bis- (4-hydroxy-3-ethylphenyl) methane, 1, 1-bis- (4-hydroxy-3-ethylphenyl) ethane, 1,1-bis- (4-hydroxy-3-ethane) Tilphenyl) propane, bis- (4-hydroxy-3-isopropylphenyl) methane, 1,1-bis- (4-hydroxy-3-isopropylphenyl) ethane, 1,1-bis- (4-hydroxy-3-isopropyl) Phenyl) propane, bis- (4-hydroxy-3-sec-butylphenyl) methane, 1,1-bis- (4-hydroxy-3-sec-butylphenyl) ethane, 1,1-bis- (4-hydroxy) -3-sec-butylphenyl) propane, 1,1-bis- (4-hydroxy-3,5-dimethylphenyl) propane, and the like.

  Among these, 2,2-bis- (4-hydroxyphenyl) propane is preferable for ease of production, and 1,1-bis- (4-hydroxyphenyl) cyclopentane is preferable from the viewpoint of mechanical properties. 1,1-bis- (4-hydroxyphenyl) cyclohexane, 2,2-bis- (4-hydroxy-3-methylphenyl) propane, 1,1-bis- (4-hydroxyphenyl) -1-phenylethane preferable. Further, among these, 2,2-bis- (4-hydroxy-3-methylphenyl) propane is particularly preferable.

In addition, although these structural units may be used individually by 1 type, they can also be used combining 2 or more types by arbitrary ratios by the desired physical property.
From the viewpoint of mechanical durability, a copolymer of 2,2-bis- (4-hydroxyphenyl) propane and 2,2-bis- (4-hydroxy-3-methylphenyl) propane was used. Sometimes a particularly significant effect is obtained.

  On the other hand, examples of the polyester resin that can be used as the second resin include those having a structural unit derived from a polybasic acid component and a polyhydric alcohol component. Examples of the polybasic acid component of the polyester resin include unsaturated acids such as maleic anhydride; aromatic saturated acids such as phthalic anhydride, terephthalic acid, and isophthalic acid; hexahydrophthalic anhydride, succinic acid, azelaic acid, and the like. The thing derived from an aliphatic saturated acid etc. is mentioned.

Moreover, a polyhydric alcohol or a polyhydric phenol is mentioned as a polyhydric alcohol component. Examples of these polyhydric alcohols or polyhydric phenols include aromatic diols and aliphatic dihydroxy compounds.
Examples of the aromatic diol include hydroquinone, resorcinol, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,8. -Dihydroxynaphthalene, 1,5-dihydroxynaphthalene, bis- (4-hydroxyphenyl) methane, bis- (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, 1,1-bis -(4-hydroxyphenyl) ethane (BPE), 1,1-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) propane, bis- (4-hydroxy-3,5 -Dimethylphenyl) methane, 2,2-bis- (4-H Loxyphenyl) butane, 2,2-bis- (4-hydroxyphenyl) pentane, 2,2-bis- (4-hydroxyphenyl) -3-methylbutane, 2,2-bis- (4-hydroxyphenyl) hexane, 2,2-bis- (4-hydroxyphenyl) -4-methylpentane, 1,1-bis- (4-hydroxyphenyl) cyclopentane, 1,1-bis- (4-hydroxyphenyl) cyclohexane, bis- ( 3-phenyl-4-hydroxyphenyl) methane, 1,1-bis- (3-phenyl-4-hydroxyphenyl) ethane, 1,1-bis- (3-phenyl-4-hydroxyphenyl) propane, 2,2 -Bis- (3-phenyl-4-hydroxyphenyl) propane, bis- (4-hydroxy-3-methylphenyl) methane, 1,1-bi -(4-hydroxy-3-methylphenyl) ethane, 2,2-bis- (4-hydroxy-3-methylphenyl) propane, 2,2-bis- (4-hydroxy-3-ethylphenyl) propane, 2 , 2-bis- (4-hydroxy-3-isopropylphenyl) propane, 2,2-bis- (4-hydroxy-3-sec-butylphenyl) propane, 1,1-bis- (4-hydroxy-3, 5-dimethylphenyl) ethane, 2,2-bis- (4-hydroxy-3,5-dimethylphenyl) propane, bis- (4-hydroxy-3,6-dimethylphenyl) methane, 1,1-bis- ( 4-hydroxy-3,6-dimethylphenyl) ethane, bis- (4-hydroxyphenyl) phenylmethane, 1,1-bis- (4-hydroxyphenyl) -1-phenyl Nilethane, 1,1-bis- (4-hydroxyphenyl) -1-phenylpropane, bis- (4-hydroxyphenyl) diphenylmethane, bis- (4-hydroxyphenyl) dibenzylmethane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxydiphenyl sulfide, phenolphthalein, 4,4 ′-[1,4-phenylenebis (1-methylvinylidene)] bisphenol, 4,4 ′-[1 , 4-phenylenebis (1-methylvinylidene)] bis [2-methylphenol] and the like.

  Preferred examples of these aromatic diols include bis- (4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, and 2,2-bis- (4-hydroxyphenyl) propane. Bis- (4-hydroxy-3,5-dimethylphenyl) methane, 2,2-bis- (3-phenyl-4-hydroxyphenyl) propane, bis- (4-hydroxy-3-methylphenyl) methane, , 1-bis- (4-hydroxyphenyl) cyclohexane, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane, 2,2-bis- (4-hydroxy-3-methylphenyl) propane, bis -(4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis- (4-hydroxy-3,5-dimethylphenyl) ethane, 2, -Bis- (4-hydroxy-3,5-dimethylphenyl) propane, bis- (4-hydroxy-3,6-dimethylphenyl) methane, 1,1-bis- (4-hydroxyphenyl) -1-phenylethane Is mentioned.

  Of these, 2,2-bis- (4-hydroxyphenyl) propane, bis- (4-hydroxy-3,5-dimethylphenyl) methane, and 1,1-bis- (4-hydroxyphenyl) cyclohexane are particularly preferable. 2,2-bis- (4-hydroxy-3-methylphenyl) propane, and particularly preferred is 2,2-bis- (4-hydroxy-3-methylphenyl) propane.

  Examples of the aliphatic dihydroxy compound include ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-pentanediol, pentamethylenediol, 2,4-pentanediol, 1,5-hexanediol, hexa Examples include methylene glycol, 1,5-heptanediol, heptamethylenediol, octamethylenediol, 1,9-nonanediol, 1,10-decamethyleneglycol, 1,6-cyclohexanediol, and preferably ethylene glycol , Propylene glycol, 1,4-butanediol and the like.

In addition, although these structural units may be used individually by 1 type, they can also be used combining 2 or more types by arbitrary ratios by the desired physical property.
From the standpoint of mechanical durability, a particularly significant effect can be obtained when 2,2-bis- (4-hydroxy-3-methylphenyl) propane is used alone.

[I-1-3. Usage ratio]
There is no restriction | limiting in the usage-ratio of 1st resin and 2nd resin, as long as the effect of this invention is acquired, it is arbitrary. However, from the viewpoint of the durability of the photoreceptor, the amount of the second resin relative to the total weight of the first resin and the second resin is usually 80% by weight or less, preferably as the amount contained in the photosensitive layer. Is 70% by weight or less, more preferably 50% by weight or less. The lower limit is not particularly limited, but is usually 1% by weight or more, preferably 5% by weight or more. If the lower limit of this range is not reached, the wear resistance may be deteriorated, and if it exceeds the upper limit, the wear resistance may be deteriorated.

  In addition, said range specification of the usage-ratio of 1st resin and 2nd resin is the weight range in the layer containing both 1st resin and 2nd resin. Therefore, when the photosensitive layer is composed of two or more layers, and there is a layer containing only one of the first resin and the second resin in those layers, only the one resin is used. The weights of the first resin and the second resin contained in the contained layer are not included in the calculation of the range definition.

[I-1-4. Predetermined repeat structure]
Furthermore, either the first resin or the second resin is a repeating structure represented by the following formula (2), that is, a repeating structure derived from 2,2-bis- (4-hydroxy-3-methylphenyl) propane. (Hereinafter referred to as “structural unit (2)” as appropriate). That is, at least one of the first resin and the second resin, preferably at least one of the second resins, particularly preferably the second resin includes the structural unit (2). Is preferred. This is because excellent wear resistance can be obtained.

  The second resin is preferably a polycarbonate resin because of good wear resistance.

Furthermore, when the second resin has a repeating structure represented by the following formula (2 ′), it is preferable because excellent slipperiness, high contact angle, excellent toner transfer rate, and the like can be obtained. In particular, this effect is more easily obtained as the component ratio of the formula (2 ′) in the second resin is higher. Specifically, in the second resin having the repeating structure represented by the formula (2 ′), the repeating structure represented by the formula (2 ′) is preferably 70% by weight or more, more preferably When it is 80% by weight or more, particularly preferably 90% by weight or more. The upper limit is ideally 100% by weight, and it is particularly preferable to use a polycarbonate resin whose repeating unit is composed only of the formula (2 ′) as the second resin. These effects are presumed to be obtained by increasing the surface roughness by mixing the resins.

  As the first resin and / or the second resin, a resin including the structural unit (2) and a resin not including the structural unit (2) may be used in combination. The structural unit (2) is a kind of hydroxy residue represented by the above formula (3).

  Moreover, the ratio (component ratio) of the weight of the structural unit (2) contained in the first resin and the second resin to the total weight of the first resin and the second resin is usually 1% by weight. Above, preferably 5% by weight or more, more preferably 10% by weight or more, and usually 90% by weight or less, preferably 80% by weight or less, more preferably 70% by weight or less.

  The weight of the structural unit (2) can be measured by hydrolyzing the binder resin and the amount of repeating units by high performance liquid chromatography or the like. In addition, the component ratio of said structural unit (2) is a component ratio in the layer which contains both 1st resin and 2nd resin. Therefore, when the photosensitive layer is composed of two or more layers, and there is a layer containing only one of the first resin and the second resin in those layers, only the one resin is used. The weights of the first resin, the second resin, and the structural unit (2) contained in the contained layer are not included in the calculation of the component ratio.

[I-1-5. Others]
Furthermore, in the photosensitive layer of the photoreceptor of the present invention, a resin other than the first resin and the second resin (combined resin) may be used in combination as the binder resin. Other resins used here include, for example, vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, polycarbonate, polyester, polyester polycarbonate, polysulfone, phenoxy, epoxy, silicone resin, and the like. And other thermoplastic resins and various thermosetting resins. Of these resins, polycarbonate resins and polyester resins are preferred. Moreover, these other resin used together may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, when using the combination resin, the first resin, the second resin, and the combination resin may be mixed and used, or may be used separately for each layer constituting the photosensitive layer. For example, the first resin and the second resin are used as one binder resin of the charge generation layer and the charge transport layer, which will be described later, and the combination resin is used as the other binder resin of the charge generation layer and the charge transport layer. Good.

  Moreover, when using combined use resin, the usage-ratio of combined use resin is not specifically limited, It is arbitrary. For example, when the combination resin is used in a layer different from the layer using the first resin and the second resin, the amount of the combination resin used is not limited. However, when the first resin, the second resin, and the combination resin are used in the same layer (photosensitive layer, charge generation layer, charge transport layer), in order to obtain the effects of the present invention sufficiently, It is preferable to use together in the range which does not exceed the ratio of 1 resin, and it is preferable not to use these other resin together especially.

[I-2. Conductive support]
There are no particular restrictions on the conductive support, but for example, metallic materials such as aluminum, aluminum alloy, stainless steel, copper and nickel; conductive powders such as metal, carbon and tin oxide were mixed to impart conductivity. Resin material: Resin, glass, paper, or the like obtained by depositing or coating a conductive material such as aluminum, nickel, ITO (indium-tin oxide) on its surface is mainly used. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.
Furthermore, as a form of the conductive support, for example, a drum shape, a sheet shape, a belt shape or the like is used. Further, a conductive material having an appropriate resistance value may be coated on a conductive support made of a metal material in order to control conductivity and surface properties or to cover defects.

Further, when a metal material such as an aluminum alloy is used as the conductive support, it may be used after anodizing, chemical conversion coating or the like. When the anodizing treatment is performed, it is desirable to perform a sealing treatment by a known method.
The surface of the support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the conductive support.

[I-3. Undercoat layer]
An undercoat layer may be provided between the conductive support and the photosensitive layer described later for improving adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as metal oxide (usually inorganic particles) are dispersed, or the like is used.

  Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One kind of these particles may be used alone, or a plurality of kinds of particles may be mixed and used.

  Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. A thing of a several crystal state may be contained by arbitrary combinations and ratios.

  In addition, various particle sizes of the metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle size is usually 1 nm or more, preferably 10 nm or more, and usually 100 nm. Below, preferably 50 nm or less.

  The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. Examples of the binder resin used for the undercoat layer include phenoxy, epoxy, polyvinyl pyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, and polyamide. Among these, alcohol-soluble copolymerized polyamide, modified polyamide, and the like are preferable because they exhibit good dispersibility and coating properties. The binder resin for the undercoat layer may be used alone or in combination of two or more in any combination and ratio. Furthermore, the binder resin can be used in the form of being cured together with the curing agent, in addition to being used only with the binder resin.

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

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

Further, as the laminated photosensitive layer, a charge generating layer and a charge transport layer are laminated in this order from the conductive support side, and a charge transport layer and a charge generation layer are laminated in this order. There are reverse laminated type photosensitive layers, and any of them can be adopted. Among these, a forward laminated photosensitive layer that can exhibit the most balanced photoconductivity is preferable.
However, in the photoreceptor of the present invention, the photosensitive layer contains the first resin and the second resin so as to include the structural unit (2). These first resin and second resin usually function as a binder resin in the photosensitive layer.

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

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

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

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

  In addition, the charge generation material may be used alone or in combination of two or more in any combination and ratio. Furthermore, when two or more charge generation materials are used in combination, the charge generation material used in combination and the mixed state in the crystalline state may be used by mixing the respective constituent elements later, or synthesis, pigmentation Alternatively, a mixed state may be generated and used in the charge generation material production / treatment process such as crystallization. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known.

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

Furthermore, the ratio between the charge generation material and the binder resin in the charge generation layer is arbitrary as long as the effects of the present invention are not significantly impaired. However, the amount of the charge generation material in the charge generation layer is usually 30 parts by weight or more, preferably 50 parts by weight or more, more preferably 100 parts by weight or more, and usually 500 parts by weight or less with respect to 100 parts by weight of the binder resin. Preferably, it is 400 parts by weight or less, more preferably 300 parts by weight or less. If the amount of the charge generating material is too small, sufficient sensitivity may not be obtained. If the amount is too large, the photosensitive member may be deteriorated in chargeability and sensitivity.
The thickness of the charge generation layer is not limited, but is usually 0.1 μm or more, preferably 0.15 μm or more, and usually 1 μm or less, preferably 0.6 μm or less.

  It should be noted that the charge generation layer has well-known plasticizers, antioxidants, ultraviolet rays for improving the film formability, flexibility, coating properties, stain resistance, gas resistance, light resistance, mechanical strength, etc. You may contain additives, such as an absorber, an electron-withdrawing compound, dye, and a pigment. Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of dyes and pigments include various pigment compounds and azo compounds. In addition, residual potential inhibitors for suppressing residual potential, dispersion aids for improving dispersion stability, leveling agents (for example, silicone oil, fluorine-based oil, etc.) for improving coating properties, surfactants Etc. can also be used as additives. In addition, an additive may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

<Charge transport layer>
The charge transport layer of the multilayer photosensitive layer contains a charge transport material, a binder resin, and other components used as necessary. Specifically, such a charge transport layer is prepared by, for example, preparing a coating solution by dissolving or dispersing a charge transport material or the like and a binder resin in a solvent. In addition, in the case of a reverse lamination type photosensitive layer, it can be obtained by coating and drying on a conductive support (or on the undercoat layer when an undercoat layer is provided).

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

As the binder resin used for the charge transport layer, the first resin and the second resin are used. As described above, when the photosensitive layer is a laminated type, it is usually preferable that the charge transport layer contains the first resin and the second resin. As described above, other resins (combined resins) may be used in combination with the first resin and the second resin.
Furthermore, the charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different components or composition ratios. When the photosensitive layer is composed of two or more layers, one or more, preferably all of the layers contain the first resin and the second resin, and the structural unit (2) is included. To do.

  In addition, when the charge generation layer contains the first resin and the second resin and the structural unit (2) is included, the binder resin for the charge transport layer is other than the first resin and the second resin. The resin may be used.

  Furthermore, in the charge transport layer, the ratio between the charge transport material and the binder resin is arbitrary as long as the effects of the present invention are not significantly impaired. However, the amount of the charge transport material in the charge transport layer is usually 30 parts by weight or more, preferably 40 parts by weight or more, more preferably 50 parts by weight or more, and usually 200 parts by weight or less with respect to 100 parts by weight of the binder resin. Preferably, it is 150 parts by weight or less, more preferably 100 parts by weight or less. If the amount of the charge transport material is too small, the electrical characteristics may be deteriorated. If the amount is too large, the coating film becomes brittle and the wear resistance may be deteriorated.

The thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less, preferably 45 μm or less from the viewpoint of long life, image stability, and high resolution. Further, the range is 30 μm or less.
In addition, the charge transport layer may contain an additive in order to improve the film formability, flexibility, coatability, stain resistance, gas resistance, light resistance and the like, as with the charge generation layer. .

<Dispersion type (single layer type) photosensitive layer>
The dispersion-type photosensitive layer is constituted by dispersing the above-described charge generating substance in the charge transport layer having the above-mentioned mixing ratio. Therefore, in the dispersion type photosensitive layer, the types of the charge transporting material and the binder resin and the usage ratio thereof are described for the charge transporting layer of the laminated type photosensitive layer when the first resin and the second resin are contained. It is the same as what I did. Therefore, the dispersion type photosensitive layer contains the first resin and the second resin as the binder resin, and further includes the structural unit (2).

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

The thickness of the dispersion type photosensitive layer is arbitrary, but is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less, preferably 45 μm or less.
Further, the dispersion type photosensitive layer may contain an additive in the same manner as the charge generation layer.

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

<Method for forming each layer>
There is no limitation on the method of forming each layer constituting the photoreceptor, and it is arbitrary. Usually, each layer constituting these photoreceptors is supported by a dip coating method, a spray coating method, a nozzle coating method, a bar coating method, a roll coating method, a blade coating method or the like known as a photosensitive layer forming method of the photosensitive member. It is formed by coating on top. Among these, the dip coating method is preferable because of its high productivity.
As a specific procedure, a known method such as sequential application of a coating solution obtained by dissolving or dispersing a substance to be contained in a layer in a solvent can be applied.

[I-5. effect]
As described above, the photosensitive layer contains the first resin and the second resin and the structural unit (2) is included, thereby improving the wear resistance against the load on the photosensitive member. Can do. It is also possible to improve the mechanical strength (for example, scratch resistance) other than the abrasion resistance of the photosensitive layer.
As described above, the reason why the above advantages can be obtained by including both the first resin and the second resin in the photosensitive layer and including the structural unit (2) is not clear, but is presumed as follows. Is done. In other words, when the first resin and the second resin are mixed, they are not completely uniform, but are very fine but exist in the photosensitive layer in a biased manner for each resin. Due to this bias, fine irregularities are formed on the surface of the photosensitive layer, and these irregularities function to reduce the contact area between the material outside the photosensitive layer and the photosensitive layer, and the abrasion resistance of the photosensitive layer. It is inferred that this can be improved.

  Therefore, in order to exhibit the above effect satisfactorily, when the photosensitive layer is composed of two or more layers, it is preferable that the outer layer contains the first resin and the second resin. Therefore, in the laminated type photosensitive layer, in the case of the normal layer type, the first resin and the second resin are used as the binder resin of the charge transport layer, and in the case of the reverse layer type, the first resin as the binder resin of the charge generation layer. It is desirable to use the resin and the second resin.

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

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

  As shown in FIG. 1, the image forming apparatus includes an electrophotographic photoreceptor 1, a charging device (charging means) 2, an exposure device (exposure means; image exposure means) 3, and a developing device (developing means) 4. Furthermore, a transfer device (transfer means) 5, a cleaning device (cleaning means) 6, and a fixing device (fixing means) 7 are provided as necessary.

  The electrophotographic photosensitive member 1 is not particularly limited as long as it is the above-described electrophotographic photosensitive member. In FIG. 1, as an example, a drum-shaped photosensitive member in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. Showing the body. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photoreceptor 1.

  The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2, but other corona charging devices such as corotron and scorotron, and contact-type charging devices such as charging brushes are often used.

  In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are cartridges having both of them (the electrophotographic photosensitive member cartridge of the present invention; hereinafter referred to as “photosensitive cartridge” as appropriate), and the main body of the image forming apparatus. Designed to be removable from. However, the charging device 2 may be provided separately from the cartridge, for example, in the main body of the image forming apparatus. For example, when the electrophotographic photoreceptor 1 or the charging device 2 deteriorates, the photoreceptor cartridge can be removed from the image forming apparatus main body, and another new photosensitive cartridge can be mounted on the image forming apparatus main body. ing. Also, the toner described later is often stored in the toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is removed. It can be removed from the main body of the image forming apparatus and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

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

In particular, in the case of an electrophotographic photoreceptor using a phthalocyanine compound as a charge generating substance, it is preferable to use monochromatic light having a wavelength of 700 nm to 850 nm, and in the case of an electrophotographic photoreceptor using an azo compound, white light or wavelength It is preferable to use monochromatic light of 700 nm or less.
Among these, [I-5. As explained in [Effect], it is preferable to perform exposure with monochromatic light having a wavelength of 380 nm to 500 nm.

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

  The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicone resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.

  The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. However, the developing roller 44 and the electrophotographic photosensitive member 1 may not be in contact with each other but may be close to each other. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The regulating member 45 is formed of a resin blade such as silicone resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such metal blade with resin. The regulating member 45 normally abuts on the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 0.05 to 5 N / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

  The agitator 42 is provided as necessary, and is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.

  The type of the toner T is arbitrary, and in addition to the powdery toner, a polymerized toner using a suspension polymerization method, an emulsion polymerization method, or the like can be used. In particular, when a polymerized toner is used, a toner having a small particle diameter of about 4 to 8 μm is preferable, and the toner particles are used in various shapes ranging from a nearly spherical shape to a shape outside the spherical shape on the potato. be able to. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

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

  There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner. However, when there is little or almost no toner remaining on the surface of the photoreceptor, the cleaning device 6 may be omitted.

  The fixing device 7 includes an upper fixing member (pressure roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. Each of the upper and lower fixing members 71 and 72 includes a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, and a fixing sheet. A member can be used. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

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

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

The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and the negative polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1.
When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.
After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.

  In addition to the above-described configuration, the image forming apparatus may have a configuration capable of performing, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

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

  The photosensitive member 1 is combined with one or more of the charging device 2, the exposure device 3, the developing device 4, the transfer device 5, the cleaning device 6, and the fixing device 7 to form an integrated cartridge (electrophotography). The electrophotographic photosensitive member cartridge may be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the charging device 2, the exposure device 3, the developing device 4, and the transfer device 5 can be integrally supported together with the photoreceptor 1 to form a cartridge. Also in this case, similarly to the cartridge described in the above embodiment, when the electrophotographic photosensitive member 1 and other members deteriorate, for example, the electrophotographic photosensitive member cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic image is obtained. By attaching the photosensitive cartridge to the image forming apparatus main body, maintenance and management of the image forming apparatus are facilitated.

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

<Measurement method of viscosity average molecular weight>
First, measurement of the viscosity average molecular weight of the resin will be described.
The resin to be measured is dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. The flow time t of the sample solution is measured in a constant temperature water bath set to 20.0 ° C. using an Ubbelohde capillary viscometer with a flow time t ₀ of the solvent (dichloromethane) of 136.16 seconds. The viscosity average molecular weight Mv is calculated according to the following formula.
a = 0.438 × η _sp +1 η _sp = (t / t ₀ ) −1
b = 100 × η _sp / C C = 6.00
η = b / a
Mv = 3207 × η ^1.205

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

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

Thereafter, 8.10 mL of acetic acid was added and stirred for 30 minutes, then stirring was stopped and the organic layer was separated. This organic layer was washed twice with 942 mL of a 0.1N aqueous sodium hydroxide solution, then washed twice with 942 mL of 0.1N hydrochloric acid, and further washed twice with 942 mL of H ₂ O. The washed organic layer was poured into 6266 mL of methanol, and the resulting precipitate was removed by filtration and dried to obtain the target resin X (first resin). It was 51,700 when the viscosity average molecular weight of the obtained resin X was measured by said measuring method. The repeating structure of Resin X is shown below.

<Manufacture of photoreceptor sheet>
[Example 1]
The undercoat layer dispersion was produced as follows. That is, a rutile type titanium oxide having an average primary particle size of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by weight of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were flowed at high speed. In a mixed solvent of methanol / 1-propanol in a mixed solvent of methanol / 1-propanol, which was introduced into a mixing kneader (“SMG300” manufactured by Kawata Co., Ltd.) and mixed at a high rotational speed of 34.5 m / sec. Then, a dispersion slurry of hydrophobized titanium oxide was obtained by dispersing with a ball mill. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [the following formula (B Compound represented by the following formula (C)] / decamethylene dicarboxylic acid [compound represented by the following formula (D)] / octadecamethylene dicarboxylic acid [in the following formula (E) The compositional molar ratio of the compound represented] is 60% / 15% / 5% / 15% / 5% of the copolymerized polyamide pellets with heating and stirring and mixing to dissolve the polyamide pellets. By performing sonic dispersion treatment, the weight ratio of methanol / 1-propanol / toluene is 7/1/2, and the hydrophobically treated titanium oxide / copolymer Containing a slip polyamide in a weight ratio of 3/1, and a solid concentration of 18.0% of the undercoat layer dispersion.

The undercoat layer-forming coating solution thus obtained was applied onto a polyethylene terephthalate sheet having aluminum deposited on the surface with a wire bar so that the film thickness after drying was 1.2 μm, dried and subtracted. A layer was provided.
Next, 10 parts by weight of oxytitanium phthalocyanine having the powder X-ray diffraction spectrum shown in FIG. In addition to 150 parts by weight of 2-dimethoxyethane, pulverization and dispersion treatment was performed with a sand grind mill to prepare a pigment dispersion. 160 parts by weight of the pigment dispersion thus obtained was added to 100 parts by weight of a 5% 1,2-dimethoxyethane solution of polyvinyl butyral (trade name # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.), and an appropriate amount of 1,2 -Dimethoxyethane was added to finally prepare a dispersion having a solid concentration of 4.0% by weight.
This dispersion was applied onto the undercoat layer with a wire bar so that the film thickness after drying was 0.4 μm, and then dried to form a charge generation layer.

  Next, 50 parts by weight of a charge transport material composed of a composition of geometric isomers represented by the following structural formula, 75 parts by weight of the resin X produced in Production Example 1, and polycarbonate resin Y (second 25 parts by weight of resin, viscosity average molecular weight 50,000), 0.05 part by weight of silicone oil as a leveling agent, and 640 parts by weight of a mixed solvent of tetrahydrofuran and toluene (80% by weight of tetrahydrofuran, 20% by weight of toluene) A coating solution for forming a charge transport layer was prepared.

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

[Example 2]
A photoreceptor sheet F was produced in the same manner as in Example 1 except that 50 parts by weight of the resin X used in the coating liquid for forming the charge transport layer of Example 1 and 50 parts by weight of the resin Y were used.

[Example 3]
A photoreceptor sheet K was produced in the same manner as in Example 1 except that 25 parts by weight of the resin X used in the coating liquid for forming the charge transport layer of Example 1 and 75 parts by weight of the resin Y were used.

[Example 4]
The resin Y used in the coating liquid for forming the charge transport layer in Example 1 was changed to polycarbonate resin Z (second resin, viscosity average molecular weight 50,000) having the following structural formula. Thus, a photoreceptor sheet B was produced.

[Example 5]
Photosensitive sheet C in the same manner as in Example 1 except that 50 parts by weight of resin X used in the charge transport layer forming coating solution of Example 1 and 50 parts by weight of resin Z instead of resin Y were used. Was made.

[Example 6]
Photosensitive sheet D in the same manner as in Example 1 except that 25 parts by weight of resin X used in the coating liquid for forming the charge transport layer of Example 1 was used, and 75 parts by weight of resin Z was used instead of resin Y. Was made.

[Comparative Example 1]
A photoreceptor sheet G was produced in the same manner as in Example 1 except that 100 parts by weight of the resin X used in the charge transport layer forming coating solution of Example 1 was used and the resin Y was not used.

[Comparative Example 2]
A photoreceptor sheet H was produced in the same manner as in Example 1 except that the resin X used in the coating liquid for forming the charge transport layer of Example 1 was not used and the resin Y was changed to 100 parts by weight.

[Comparative Example 3]
A photoreceptor sheet I was produced in the same manner as in Example 4 except that the resin X used in the coating solution for forming the charge transport layer of Example 4 was not contained and the resin Z was 100 parts by weight.

[Comparative Example 4]
Photosensitive sheet M in the same manner as in Example 1 except that the resin X used in the coating solution for forming the charge transport layer in Example 1 is a polyester resin V (viscosity average molecular weight 31,000) having the following structural formula. Was made.

[Comparative Example 5]
Except for 25 parts by weight of the resin X used in the coating liquid for forming the charge transport layer of Example 1 and 75 parts by weight of the polyester resin W (viscosity average molecular weight 22,000) having the following structural formula: In the same manner as in Example 1, a photoreceptor sheet L was produced.

[Comparative Example 6]
The resin X used in the coating liquid for forming the charge transport layer of Example 1 is 50 parts by weight, and in addition to the resin Y, a polycarbonate resin Q having the following repeating structure (second resin, viscosity average molecular weight 40, 100) A photoreceptor sheet R was produced in the same manner as in Example 1 except that 50 parts by weight were used.

[Comparative Example 7]
A photoreceptor sheet S was produced in the same manner as in Example 1 except that the resin X used in the charge transport layer forming coating solution of Comparative Example 6 was not used and the resin Q was changed to 100 parts by weight.

<Abrasion test>
The photoreceptor sheets prepared in the above examples and comparative examples were each cut into a circle having a diameter of 10 cm and subjected to wear evaluation with a Taber abrasion tester (manufactured by Taber). Test conditions were measured by comparing the weight before and after the test with 1000 wheels without load (the weight of the wear wheel) under the atmosphere of 23 ° C. and 50% RH and without wear (self-weight of the wear wheel). did. The results are shown in Table 1.

<Electrical property test 1>
The photoconductor sheets prepared in the above-described examples and comparative examples were mounted on a photoconductor characteristic tester (model EPA8100 manufactured by Kawaguchi Electric Co., Ltd.), and the photoconductor was negatively charged with a corona current of 35 μA in the dark. After (Vo), 780 nm light is continuously irradiated, the half-exposure amount (E _1/2 ) required for the surface potential to decrease from −700 V to −350 V, and the residual potential when irradiated with 10 μJ / cm ^2. (Vr) was measured. The results are shown in Table 1.

<Evaluation of surface properties>
The electrophotographic photosensitive member described above was cut into a size of 60 mm in width and 130 mm in length, and fixed with an adhesive tape on a reciprocating table of a FR-2 type abrasion tester manufactured by Suga Test Instruments Co., Ltd. A load of 7.8 N was applied, and polishing was performed by reciprocating 300 times on the electrophotographic photosensitive member with a 3M company's Wetdry Tri-M-ite Paper 2000. Thereafter, a load of 7.8 N was applied and polished on the electrophotographic photosensitive member 300 times by JK Wiper (registered trademark) 150-S manufactured by Crecia Co., Ltd.
About these electrophotographic photoreceptors before and after surface polishing, the contact angle with pure water was measured using a FACE CA-D contact angle meter manufactured by Kyowa Interface Science Co., Ltd. The results are shown in Table 2.

  Further, the coefficient of friction of these electrophotographic photoreceptors before and after surface polishing was measured using a Heidon-14 type surface property tester manufactured by Shinto Kagaku Co., Ltd. At this time, a nonwoven fabric SOFPADS manufactured by Dynic Co., Ltd. having a width of 10 mm and a length of 12 mm was used as the friction body, and the measurement was performed under a load of 2.9 N and a sweep speed of 100 mm / min. The results are shown in Table 2.

  Based on the above results, a photoreceptor having a photosensitive layer using the first resin (resin X) and the second resin (resins Y, Z) in combination and further including the structural unit (2) is shown in Table 1. As shown in the test results, it is understood that the wear resistance is excellent.

  When the first resin and the second resin are used in combination, the wear resistance is superior to the case where either one is used alone (Comparative Examples 1, 2, and 3). It can be seen that this is a phenomenon. Further, the photoconductors of the examples also have excellent wear resistance compared to the photoconductor M (Comparative Example 4) when the polyester resin V not containing the diphenyl ether-dicarboxylic acid residue represented by the formula (1) is used. This shows that a polyester resin containing a diphenyl ether-dicarboxylic acid residue represented by the formula (1) is essential.

  Further, as shown in Comparative Example 1, the polyester resin X alone has good wear resistance but poor electrical characteristics. In the photoconductor of the example, the electrical characteristics are improved because it is a mixture with a polycarbonate resin having good electrical characteristics.

  Also, when a polycarbonate resin containing the formula (2 ′) is used as the second resin, as shown in Table 2, in addition to wear resistance, it has excellent slipperiness and a high contact angle. Have a good toner transfer rate. This effect is particularly great when the second resin is a polycarbonate resin containing 70% by weight or more of the repeating structure represented by the formula (2 ').

  From the above results, it can be seen that the photoconductor using the first resin and the second resin together and having the photosensitive layer including the structural unit (2) is extremely excellent in wear resistance.

Next, evaluation with a drum-shaped photosensitive member (photosensitive drum) was performed in the following manner.
[Example 7]
The surface of a cylinder made of an aluminum alloy having a mirror-finished outer diameter of 30 mm, length of 375.8 mm, and wall thickness of 1.0 mm is subjected to anodizing treatment, and then a sealing agent mainly composed of nickel acetate. By carrying out the sealing treatment, an anodic oxide coating (alumite coating) of about 6 μm was formed.

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

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

  Next, 35 parts each of compound (R) and compound (S) having the following structure as a charge transport material, 70 parts in total, 75 parts of polyester resin X produced in Production Example 1 as a binder resin, polycarbonate resin 25 parts of Y and 0.05 part of silicone oil (trade name KF96 Shin-Etsu Chemical Co., Ltd.) as a leveling agent are mixed with 640 parts of a tetrahydrofuran / toluene (8/2) mixed solvent to form a charge transport layer. A coating solution was prepared.

  The charge transport layer forming coating solution is dip-coated on the above-described charge generation layer so that the film thickness after drying is 18 μm, thereby forming a charge transport layer, and a photosensitive drum having a laminated photosensitive layer T was obtained.

[Comparative Example 8]
A charge transport layer forming coating solution was prepared in the same manner as in Example 7 except that the resin X used in the charge transport layer forming coating solution of Example 7 was changed to polyester resin V. Using this coating solution, a photoreceptor drum U was obtained in the same manner as in Example 7.

[Evaluation]
The electrophotographic photoreceptors T and U obtained as described above were subjected to the following electrical characteristic test and actual machine evaluation. These results are summarized in Table 3.

<Electrical property test 2>
Attached to an electrophotographic characteristic evaluation apparatus manufactured according to the Electrophotographic Society measurement standard (basic and applied electrophotographic technology, edited by Electrophotographic Society, Corona, page 404-405), and charged and exposed according to the following procedures. The electrical characteristics were evaluated by the cycle of potential measurement and static elimination.

The photosensitive member is charged so that the initial surface potential becomes −700 V, and the halogen lamp light is irradiated with monochromatic light of 405 nm by an interference filter, and the irradiation energy (μJ / cm ² ) was defined as sensitivity E1. Further, the surface potential after exposure (−V) when exposed at 2.0 μJ / cm ² was VL1.
Similarly, the sensitivity E2 and the post-exposure surface potential VL2 were measured in exactly the same procedure using a monochromatic light of 760 nm using an interference filter.

When measuring E1, VL1, E2, and VL2, the time required from the exposure to the potential measurement was 200 ms. The measurement environment was a temperature of 25 ° C. and a relative humidity of 50%.
The photoconductor of Example 7 sufficiently transmitted light of 405 nm, whereas the photoconductor of Comparative Example 8 had a significantly reduced sensitivity because the photosensitive layer absorbed light of 405 nm.

<Evaluation of actual machine>
The produced photosensitive drum was mounted on a black drum cartridge of a commercially available tandem type color printer (Microline Pro 9800PS-E manufactured by Oki Data Co., Ltd.) compatible with A3 printing, and mounted on the printer.

Specifications of MICROLINE Pro 9800PS-E · 4 tandem · Color 36ppm, Monochrome 40ppm
・ 1200 dpi
・ DC contact roller charging ・ Writing with LED

Next, a personal computer was connected to this printer, a grayscale (halftone) image was input, and the density of the output printout was confirmed. As a result, either the photoconductor T of Example 7 or the photoconductor U of Comparative Example 8 was used. An image with a good density was also obtained with this photoconductor.
Also, the exposure part of the same color printer (Microline Pro 9800PS-E manufactured by Oki Data Co., Ltd.) was remodeled so that light from a small spot irradiation type blue LED (B3MP-8: 470 nm) manufactured by Nisshin Electronics could be irradiated to the photoconductor. Remodeled.
When the photoconductor T was attached to this remodeling apparatus and a line was drawn, a good image was obtained. Further, when a strobe illumination power source LPS-203KS was connected to the small spot irradiation type blue LED and a point was written, a point image having a radius of 8 mm could be obtained.

  From the results of the actual machine evaluation and the electrical property test, the photoreceptor T of Example 7 shows sufficient electrical properties even in the purple to blue exposure (405 nm), so even if it is exposed with a blue LED near a wavelength of 400 nm, Although an equivalent image can be obtained by performing some exposure amount adjustment, it is estimated with high accuracy that the photoconductor U of Comparative Example 8 requires a large exposure adjustment.

  Next, 30,000 images of a text document having a printing area of about 5% were formed under conditions of a temperature of 25 ° C. and a humidity of 50%. The relative value of the average film reduction amount at this time (reduced film thickness of the photoconductor T of Example 7 / reduced film thickness of the photoconductor U of Comparative Example 8) is 0.62, and the photoconductor T of Example 7 is Excellent wear resistance.

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

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

Explanation of symbols

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

Claims (6)

In an electrophotographic photoreceptor having a photosensitive layer on a conductive support,
A polyester resin containing a repeating structure represented by the following formula (1) (hereinafter referred to as “first resin”);
Polycarbonate resin (hereinafter referred to as "second resin"),
An electrophotographic photosensitive member, wherein at least the second resin includes a repeating structure represented by the following formula (2).

(In the formula (1), Ar ^{1 to} Ar ⁴ each independently represents an arylene group which may have a substituent, and X ¹ represents a single bond or a divalent group.)

2. The electrophotographic photoreceptor according to claim 1, wherein the second resin is a polycarbonate resin containing 70% by weight or more of a repeating structure represented by the following formula (2 ′).

The electrophotographic photoreceptor according to claim 1 , wherein the electrophotographic photoreceptor is used with monochromatic writing light having a wavelength of 380 to 500 nm. The electrophotographic photosensitive member according to any one of claims 1 to 3 ,
Charging means for charging the electrophotographic photosensitive member;
Image exposure means for performing image exposure on the charged electrophotographic photosensitive member to form an electrostatic latent image;
Developing means for developing the electrostatic latent image with toner;
An image forming apparatus comprising: a transfer unit that transfers the toner to a transfer target. The image forming apparatus according to claim 4 , wherein the exposure unit performs exposure with monochromatic light having an exposure wavelength of 380 to 500 nm. The electrophotographic photosensitive member according to any one of claims 1 to 3 ,
Charging means for charging the electrophotographic photoreceptor, image exposure means for performing image exposure on the charged electrophotographic photoreceptor to form an electrostatic latent image, developing means for developing the electrostatic latent image with toner, and An electrophotographic cartridge comprising: at least one transfer unit that transfers toner to a transfer target.

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