JP6648486B2 - Method for producing polyester resin and method for producing electrophotographic photoreceptor - Google Patents

Description

  The present invention relates to a method for producing a polyester resin, and more particularly, to a method for producing a polyester resin having excellent solubility and abrasion resistance.

Polyester resin has excellent heat resistance and mechanical properties, and is used as a material for various parts in various fields. In addition, since polyester resins have excellent transparency, they have recently been used in the optical field.
As a method of using the polyester resin in the optical field, there is a binder resin for an electrophotographic photosensitive member. The electrophotographic photoreceptor is repeatedly used in an electrophotographic process, that is, in a cycle of charging, exposure, development, transfer, cleaning, charge elimination, and the like. Examples of such deterioration include chemical damage to the photosensitive layer caused by strongly oxidizing ozone and NOx generated from a corona charger commonly used as a charger, and carriers (current) generated by image exposure due to the photosensitive layer. There is chemical or electrical deterioration such as flowing inside, or decomposing of the photosensitive layer composition caused by static elimination light and external light. Further, there is mechanical deterioration such as abrasion of the photosensitive layer surface, generation of scratches, and peeling of the film due to contact with a cleaning blade, a magnetic brush or the like, contact with a developer, paper, or the like. Such damage due to mechanical deterioration is likely to appear on an image and directly impairs image quality, which is a major factor that limits the life of the photoconductor. In the case of a general photoreceptor having no functional layer such as a surface protective layer, the photosensitive layer is particularly susceptible to such a load. The photosensitive layer is usually composed of a binder resin and a photoconductive substance, and it is the binder resin that substantially determines the strength.However, since the doping amount of the photoconductive substance is considerably large, it is necessary to provide sufficient mechanical strength. Has not been reached. In recent years, polyester resins having excellent sensitivity and abrasion resistance have been used as binder resins for photosensitive layers (see Patent Documents 1 to 7).

  Although various methods for producing a polyester resin are known, interfacial polymerization for obtaining a polyester resin having a high molecular weight, a small coloration and a high purity is widely used. However, for example, when an attempt is made to produce a polyester resin by an interfacial polymerization method using an easily oxidizable monomer such as hydroquinone, the polyester resin is easily oxidized in an aqueous alkaline solution to an oxidized product such as quinone. Since this oxidant does not react with dicarboxylic acid chloride, it is difficult to incorporate an assumed amount into the resin, and the resin is colored by the oxidant remaining in the resin. Due to such a problem, the structure of a monomer that can be used for a polyester resin in general interfacial polymerization is limited. Methods for preventing such monomer oxidation during polymerization are being studied, and a polymerization method in which an excessive amount of an antioxidant is added is known (see Patent Document 8).

JP-A-3-6567 JP-A-9-22126 JP-A-10-20514 JP 2001-265021 A JP 2004-294750 A JP 2006-53549 A JP 2008-293006 A JP 2010-83986 A

However, according to the study of the present inventor, the photoreceptor using the polyester resin of the technology described in Patent Documents 1 to 7 described above has a mechanical strength of a high-life and high-end model that prints 100,000 sheets or more. However, a higher performance polyester resin was required.
In addition, the technology described in Patent Document 8 increases the number of polyester resin structures that can be manufactured. However, since a large amount of an antioxidant is used, it remains as an impurity in a polymerized resin and may deteriorate electrical characteristics. is there. Further, it is necessary to strictly remove oxygen in the aqueous solution during the polymerization, which is difficult in actual production.

  The present invention has been made in view of the above problems. That is, an object of the present invention is to provide a method for easily producing a polyester resin having excellent electrical properties, solubility and abrasion resistance, and to provide an electrophotographic apparatus having excellent abrasion resistance to practical loads and excellent electrical properties. It is to provide a photoreceptor.

  The present inventors have conducted intensive studies on a method for producing a polyester resin that can solve the above-mentioned problems. As a result, in the production of the polyester resin, the amount of residual carboxylic acid chloride monomer in the ester oligomer via the ester oligomer It was found that by controlling the content of the polyester resin, a polyester resin having excellent electrical properties, solubility and abrasion resistance when contained in an electrophotographic photosensitive member could be easily produced, and the present invention was completed based on such findings. That is, the gist of the invention resides in the following <1> to <7>.

<1> A method for producing a polyester resin containing a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), wherein the divalent resin is represented by the following formula (4-1) Reacting a phenol with a dicarboxylic acid chloride represented by the following formula (5) to obtain an ester oligomer, and reacting the ester oligomer with a dihydric phenol represented by the following formula (4-2) to form a polyester A method for producing a polyester resin, comprising a step of obtaining a resin, wherein a residual amount of a dicarboxylic acid chloride monomer represented by the following formula (5) in the ester oligomer satisfies the following formula (6).

(In the formula (1), X ¹ is a divalent group represented by the following formula (3), and Y ¹ and Y ² are each independently a divalent group. In the formula (2), X ² is a group containing a divalent aromatic, provided that Y ¹ may be the same as Y ² and X ² is not the same as X ¹ .

(In the formula (3), R ¹ and R ² each independently have a hydrogen atom, an alkyl group which may have a substituent having 1 to 20 carbon atoms, and a substituent having 1 to 20 carbon atoms. Represents an optionally substituted alkoxyl group or an aromatic group optionally having a substituent having 1 to 20 carbon atoms, wherein n ¹ and n ² each represent an integer of 0 to ^4. R ³ and R ⁴ represent Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic group which may have a substituent having 1 to 20 carbon atoms, provided that R ³ and R ⁴ are bonded to each other; (A ring may be formed.)

<2> In the step of obtaining the ester oligomer, the charged molar ratio of the dihydric phenol represented by the formula (4-1) and the dicarboxylic acid chloride represented by the formula (5) is as follows:

<1> The method for producing a polyester resin according to <1>,
<3><1> or <2>, wherein X ² in the formula (2) is a group containing at least one kind of divalent aromatic selected from the following formulas (7) to (10). > The method for producing a polyester resin described in the above.

(In the formula (7), R ⁵ represents any one of a hydrogen atom, an alkyl group which may have a substituent having 1 to 20 carbon atoms, an alkoxyl group, an aromatic group which may be substituted, and a halogen group. , ^{n 3} is an integer of 0-4.)

(In the formula (8), R ⁶ represents any one of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxyl group, an aromatic group which may be substituted, and a halogen group. , ^{n 4} is an integer of 0-6.)

(In the formula (9), R ⁷ and R ⁸ each represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxyl group, an aromatic group which may be substituted, and a halogen group. Wherein n ⁵ and n ⁶ are integers of 0 to 4. W ¹ represents any ^one of a single bond, oxygen, sulfur and a methylene group.)

(In the formula (10), Ar ¹ and Ar ² each independently represent an arylene group which may have a substituent having 6 to 16 carbon atoms. Z is an arylene which may have a substituent. Is an alkylene group having 2 to 20 carbon atoms which may have a group or a substituent, and s is an integer of 0 or 1.) <4> Represented by the above formula (2) in the above polyester resin The content of the repeating unit satisfies 0.45 ≧ (2) / ((1) + (2)) ≧ 0.05 in molar ratio with the repeating unit represented by the formula (1). The method for producing a polyester resin according to any one of <1> to <3>.
<5> wherein Y ¹ and Y ² in the formulas (1) and (2) are divalent groups represented by the following formula (11), wherein <1> to <4 > The method for producing a polyester resin according to any one of the above items.

(In the formula (11), Ar ³ and Ar ⁴ each independently represent an arylene group which may have a substituent. Z is a single bond, an oxygen atom, a sulfur atom, or a formula (12) Or a divalent group having a structure represented by the formula (13), wherein R ⁹ and R ¹⁰ in the formula (12) each independently represent a hydrogen atom, an alkyl group, an aryl group, or Represents a cycloalkylidene group formed by combining R ⁹ and R ^10. Further, in the formula (13), R ¹¹ represents an alkylene group, an arylene group, or a group represented by the formula (14). In the formula (14), R ¹² and R ¹³ each independently represent an alkylene group, Ar ⁵ represents an arylene group, and k represents an integer of 0 to ^5. )

<6> The method for producing a polyester resin according to any one of <1> to <5>, wherein the method for producing the polyester resin is a solution polymerization method.
<7> In an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, the photosensitive layer includes a repeating unit represented by the formula (1) and a repeating unit represented by the formula (2). The polyester resin contains a dicarboxylic acid chloride monomer represented by the formula (5) and an ester oligomer satisfying the formula (6), and a divalent compound represented by the formula (4-2). Wherein the ester oligomer is obtained from a dihydric phenol represented by the following formula (4-1) and a dicarboxylic acid chloride represented by the above formula (5). body.

  The polyester production method of the present invention is a method for providing a polyester resin having excellent solubility and abrasion resistance by devising the order of adding monomers having different solubility. Further, by using the polyester resin produced by the production method for an electrophotographic photoreceptor, a resin excellent in various properties such as abrasion resistance and electric properties can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to manufacture polyester resin excellent especially in solubility and abrasion resistance.

FIG. 1 is a conceptual diagram illustrating an embodiment of an image forming apparatus using an electrophotographic photosensitive member according to the present invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail. It should be noted that the present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist.
≪Polyester resin≫
The polyester resin to which the production method of the present invention is applied has a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2).

In the formula (1), X ¹ is a divalent group represented by the following formula (3), and Y ¹ and Y ² are divalent groups. In the formula (2), X ² is a group containing a divalent aromatic. However, ^{X 2} is not the same as ^{X 1.}

In the formula (3), R ¹ and R ² each independently have a hydrogen atom, an alkyl group which may have a substituent having 1 to 20 carbon atoms, and a substituent having 1 to 20 carbon atoms. Represents an optionally substituted alkoxyl group or an aromatic group which may have a substituent having 1 to 20 carbon atoms. The carbon number is the carbon number of the entire group including the substituent. Examples of the substituent for R ¹ and R ² include an alkyl group, an alkoxy group, and a halogen atom, and preferably have no substituent. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a cyclohexyl group, and the like. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, and an n-butoxy group. Specific examples of the aromatic group which may have a substituent include a phenyl group, a naphthyl group, and a 4-methylphenyl group. Among these, a methyl group and an ethyl group are preferred in view of solubility, abrasion resistance, and simplicity in production.

n ¹ and n ² are each an integer of 0 to 4. From the viewpoint of wear resistance, it is preferably an integer of 0 to 2, and particularly preferably 0 or 1.
R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic group which may have a substituent having 1 to 20 carbon atoms. However, R ³ and R ⁴ may combine with each other to form a ring. The carbon number is the carbon number of the entire group including the substituent. As the substituents for R ³ and R ⁴ , those exemplified as the substituents for R ¹ and R ² can be applied. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group. Specific examples of the aromatic group which may have a substituent include a phenyl group, a naphthyl group and a biphenyl group. Specific examples of the case where R ³ and R ⁴ are bonded to each other to form a ring include a cyclopentylidene group, a cyclohexylidene group, and a cyclohexylidene group substituted with 1 to 3 methyl groups. R ³ and R ⁴ are preferably a hydrogen atom, a methyl group, an ethyl group, or a cyclohexylidene group in view of solubility, abrasion resistance, and simplicity in production.

Specific examples of bisphenol that is a source of the divalent group represented by the formula (3) include bis- (4-hydroxyphenyl) methane, bis- (4-hydroxy-3-methylphenyl) methane, and bis- (4-hydroxy-3-methylphenyl) methane. -(3,5-dimethyl-4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane, 1,1 -Bis- (3,5-dimethyl-4-hydroxyphenyl) ethane, 1,1-bis- (4-hydroxyphenyl) propane, 1,1-bis- (4-hydroxy-3-methylphenyl) propane, 1-bis- (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydrokey 3-methyl Phenyl) propane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) propane, 1,1-bis- (4-hydroxyphenyl) cyclohexane, 1,1-bis- (4-hydrokey 3- Methylphenyl) cyclohexane, 1,1-bis- (3,5-dimethyl-4-hydroxyphenyl) cyclohexane, 1,1-bis- (4-hydroxyphenyl) -1-phenylethane and the like. Among these, bis- (4-hydroxyphenyl) methane, bis- (4-hydroxy-3-methylphenyl) methane, bis- (3,5-dimethyl) are taken into consideration in view of the simplicity of production, solubility, and electrical characteristics. -4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 1,1-bis- (4-hydroxy-3-methylphenyl) ethane, 2,2-bis- (4-hydroxy Phenyl) propane, 2,2-bis- (4-hydroxy-3-methylphenyl) propane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) propane, 1,1-bis- (4 -Hydroxyphenyl) cyclohexane is preferred. Further considering mechanical properties, bis- (4-hydroxyphenyl) methane, bis- (4-hydroxy-3-methylphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 1,1- Bis- (4-hydroxy-3-methylphenyl) ethane, 2,2-bis- (4-hydroxy-3-methylphenyl) propane, and 1,1-bis- (4-hydroxyphenyl) cyclohexane are more preferred.

X ² in the formula (2) is a group containing a divalent aromatic that is not the same as X ¹ . Examples of the group containing a divalent aromatic include a divalent group such as the above formula (3) and a divalent group represented by the following formulas (7) to (10). From the viewpoint of printing durability, a group containing at least one kind of divalent aromatic selected from the following formulas (7) to (10) is preferable.

In the formula (7), R ⁵ is a hydrogen atom, an alkyl group which may have a substituent having 1 to 20 carbon atoms, an alkoxyl group which may have a substituent having 1 to 20 carbon atoms, Represents an aromatic group which may have 1 to 20 substituents, or a halogen group. The carbon number is the carbon number of the entire group including the substituent. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a cyclohexyl group, and the like. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, and an n-butoxy group. Specific examples of the aromatic group which may have a substituent include a phenyl group, a naphthyl group, and a methyl-substituted phenyl group. Examples of the halogen group include a fluoro group, a chloro group, and a bromo group. A methyl group, a phenyl group, a fluoro group, and a chloro group are preferred from the viewpoint of solubility, abrasion resistance, and ease of production. n ³ is an integer of 0 to 4. From the viewpoint of printing durability, it is preferably an integer of 0 to 2, and particularly preferably 0. Specific examples of the dihydric phenol that is a source of the divalent group represented by the formula (7) include hydroquinone, methylhydroquinone, chlorohydroquinone, fluorohydroquinone, resorcinol, catechol, and the like. From the viewpoint of printing durability, hydroquinone is preferred.

In the formula (8), R ⁶ is a hydrogen atom, an alkyl group which may have a substituent having 1 to 20 carbon atoms, an alkoxyl group which may have a substituent having 1 to 20 carbon atoms, Represents an aromatic group which may have 1 to 20 substituents, or a halogen group. Specific examples of R ⁶ include those equivalent to R ⁵ . n ⁴ is an integer from 0 to 6. From the viewpoint of printing durability, it is preferably an integer of 0 to 2, particularly preferably 0. Specific examples of the dihydric phenol that is a source of the divalent group represented by the formula (8) include 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, Examples thereof include 6-dihydroxynaphthalene and 2,7-dihydroxynaphthalene. From the viewpoint of printing durability, 2,6-dihydroxynaphthalene and 2,7-dihydroxynaphthalene are preferred.

In the formula (9), R ⁷ and R ⁸ are each independently an alkyl group which may have a substituent having 1 to 20 carbon atoms, or an alkoxyl which may have a substituent having 1 to 20 carbon atoms. Represents a group, an aromatic group which may have a substituent having 1 to 20 carbon atoms, or a halogen group. Specific examples of R ⁷ and R ⁸ include those equivalent to R ⁵ described above. n ^{5, n 6} is an integer of 0-4. From the viewpoint of printing durability, it is preferably an integer of 0 to 2, and particularly preferably 0 or 1. W ¹ represents a single bond, oxygen, or sulfur. Specific examples of the dihydric phenol which is the source of the divalent group represented by the formula (9) include 4,4′-biphenol, 4,4′-dihydroxy-3,3′-dimethylbiphenyl, , 4'-Dihydroxy-3,3 ', 5,5'-tetramethylbiphenyl, 4,4'-dihydroxy-2,2', 3,3 ', 5,5'-hexamethylbiphenyl, 4,4' -Dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenylether, 4,4'-dihydroxy-3,3 ', 5,5'-tetramethyldiphenylether, 4,4'-dihydroxydiphenylsulfide, , 4'-dihydroxy-3,3'-dimethyldiphenylsulfide, 4,4'-dihydroxy-3,3 ', 5,5'-tetramethyldiphenylsulfide and the like. From the viewpoint of printing durability and availability, 4,4'-biphenol, 4,4'-dihydroxy-3,3'-dimethylbiphenyl, 4,4'-dihydroxy-3,3 ', 5,5'- Tetramethylbiphenyl and 4,4'-dihydroxydiphenyl ether are preferred.

In the formula (10), Ar ¹ and Ar ² each independently represent an arylene group which may have a substituent having 6 to 16 carbon atoms. Z represents an arylene group which may have a substituent or an alkylidene group which may have a substituent, and s is an integer of 0 or 1.
In the formula (10), specific examples of the arylene group in Ar ¹ and Ar ² include a phenylene group, a naphthylene group, an anthrene group, a phenanthrylene group, a pyrenylene group, and a biphenylene group. A phenylene group is preferred from the viewpoint of simplicity in production. Examples of the substituent of the arylene group include an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, a halogenated alkyl group, a halogen group, and a benzyl group. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, an isobutyl group, a cyclohexyl group, and the like. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a cyclohexoxy group. Examples of the halogenated alkyl group include a chloromethyl group and a fluorinated alkyl group. Examples of the halogen group include a fluorine group, a chloro group, and a bromo group. From the viewpoint of wear resistance, an alkyl group having 1 to 6 carbon atoms and an alkoxyl group having 1 to 6 carbon atoms are preferable, and a methyl group and an ethyl group are particularly preferable.

  In the formula (10), specific examples of the arylene group which may have a substituent in Z include a p-phenylene group, an m-phenylene group, and a structure represented by the following formula (15). . Specific examples of the alkylidene group which may have a substituent include ethylidene, propylidene, cyclohexylidene, 1,4-dimethylcyclohexane and the like. From the viewpoint of simplicity in production, a p-phenylene group or a structure represented by the following formula (15), ethylidene is preferred.

In the formula (15), R ^{14 to} R ¹⁷ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.
Specific examples of the alkyl group in the formula (15) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, an isobutyl group, a cyclohexyl group, and the like. R ^{14 to} R ¹⁷ are preferably a hydrogen atom or a methyl group from the viewpoint of solubility, abrasion resistance, and simplicity in production.

s is preferably an integer of 0 or 1 from the viewpoint of wear resistance, and more preferably 0 from the viewpoint of solubility.
Specific examples of the dihydric phenol which is a source of the divalent group represented by the formula (10) are shown below.

Further, the formula (4-1) and (4-2), ^{X 2} and ^{X 1} is a dihydric phenol corresponding to ^{X 2} and ^{X 1} are as defined above.
Preferably, Y ¹ and Y ² in the formulas (1) and (2) are divalent groups represented by the following formula (11). Preferably, Y ¹ and Y ² are the same.

Ar ³ and Ar ⁴ each independently represent an arylene group which may have a substituent. W ² represents a single bond, an oxygen atom, a sulfur atom, a divalent organic residue having a structure represented by the formula (12), or a divalent organic residue having a structure represented by the formula (13) Represent. R ⁹ and R ¹⁰ in the formula (12) each independently represent a hydrogen atom, an alkyl group, or an aryl group, or a cycloalkylidene group formed by combining R ⁹ and R ¹⁰ . Further, in the formula (13), R ¹¹ represents an alkylene group, an arylene group, or a group represented by the formula (14). In the formula (14), R ¹² and R ¹³ each independently represent an alkylene group, and Ar ⁵ represents an arylene group. k represents an integer of 0 to 5.

In the formula (11), Ar ³ and Ar ⁴ are preferably an arylene group having 6 to 20 carbon atoms, and examples thereof include a phenylene group, a naphthylene group, a biphenylene group, an anthrylene group, a phenanthrylene group, and a pyrenylene group. Among them, a phenylene group, a naphthylene group, or a biphenylene group is more preferable in terms of production cost.
Examples of the substituent that the arylene group may have independently include an alkyl group, an alkoxy group, an aryl group, a condensed polycyclic group, and a halogen group. Considering the mechanical properties of the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, a phenyl group or a naphthyl group is preferable as the aryl group, and a fluorine, chlorine, bromine or iodine atom as the halogen group. Is preferably a methoxy group, an ethoxy group, or a butoxy group as an alkoxy group, and an alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and more preferably 1 to 2 carbon atoms. Is particularly preferred, and specifically a methyl group is particularly preferred. The number of substituents of Ar ³ and Ar ⁴ is not particularly limited, but is preferably 3 or less, more preferably 2 or less, and particularly preferably 1 or less. From the viewpoint of abrasion resistance and ease of production, Ar ³ and Ar ⁴ are preferably the same arylene group having the same substituent, and more preferably an unsubstituted phenylene group.

In the formula (12), R ⁹ and R ¹⁰ each independently represent a hydrogen atom, an alkyl group, or an aryl group, or a cycloalkylidene group formed by combining R ⁹ and R ¹⁰ . Examples of the alkyl group of R ⁹ and R ¹⁰ include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the aryl group include a phenyl group and a naphthyl group. Examples of the cycloalkylidene group formed by combining R ⁹ and R ¹⁰ in the formula (12) include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. In Formula (13), R ¹¹ is an alkylene group, an arylene group, or a group represented by Formula (14). In Formula (14), R ¹² and R ¹³ each independently represent an alkylene group. , Ar ⁵ represents an arylene group. In the formula (13), examples of the alkylene group of R ¹¹ include a methylene group, an ethylene group, and a propylene group, and examples of the arylene group of R ¹¹ include a phenylene group and a terphenylene group. Specific examples of the group represented by the formula (14) include a group represented by the following formula (15). W ² is preferably an oxygen atom from the viewpoint of wear resistance.

  In the formula (11), k is an integer of 0 to 5. In light of wear resistance, it is preferably an integer of 0 or 1, and particularly preferably 1. When k is 0, specific examples of the divalent carboxylic acid serving as a source of the divalent group represented by the formula (11) include terephthalic acid and isophthalic acid. When k is 1, the formula (11) is particularly preferably the following general formula (16).

In the formula (16), R ¹⁸ and R ¹⁹ each independently represent a hydrogen atom, an alkyl group, an aryl group, a halogen group, or an alkoxy group, and n and m each independently represent an integer of 0 to 4.
In the formula (16), R ¹⁸ and R ¹⁹ are, for example, a hydrogen atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group and an isopropyl group; an aryl group such as a phenyl group and a naphthyl group; And a halogen group such as a chlorine atom, a bromine atom and an iodine atom; and an alkoxy group such as a methoxy group, an ethoxy group and a butoxy group. R ¹⁸ and R ¹⁹ are particularly preferably a hydrogen atom or a methyl group in view of the simplicity of production of the divalent carboxylic acid compound for deriving the divalent group represented by the formula (16). n and m are each independently an integer of 0 to 4, and particularly preferably n = m = 0. Specific examples of the divalent carboxylic acid compound for deriving a divalent group represented by the formula (16) include, for example, diphenyl ether-2,2′-dicarboxylic acid, diphenyl ether-2,4′-dicarboxylic acid, diphenyl ether- 4,4'-dicarboxylic acid and the like can be mentioned. Among these, diphenyl ether-4,4'-dicarboxylic acid is particularly preferred in view of simplicity in production.

  The dicarboxylic acid residue can be used in combination of a plurality of compounds as necessary. Specific examples of the divalent carboxylic acid compound which may be combined include, for example, adipic acid, suberic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, toluene-2,5-dicarboxylic acid, p-xylene-2,5 -Dicarboxylic acid, pyridine-2,3-dicarboxylic acid, pyridine-2,4-dicarboxylic acid, pyridine-2,5-dicarboxylic acid, pyridine-2,6-dicarboxylic acid, pyridine-3,4-dicarboxylic acid, pyridine -3,5-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-2,3-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, biphenyl-2,2'-dicarboxylic acid, biphenyl-4,4 '-Dicarboxylic acid, diphenyl ether-2,2'-dicarboxylic acid, diphenyl ether-2,3'-dicarboxylic acid, diphenyl Ether 2,4'-dicarboxylic acid, diphenyl ether-3,3'-dicarboxylic acid, diphenyl ether-3,4'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid. Considering the simplicity of production of the dicarboxylic acid component, isophthalic acid, terephthalic acid, and diphenyl ether-4,4'-dicarboxylic acid are particularly preferred.

Further, the formula (5) is a divalent carboxylic acid compound corresponding to Y ^1, Y ¹ are as defined above.
The content of the repeating unit represented by the above formula (2) in the polyester resin is 0.45 ≧ (2) / ((1) + (molar ratio) to the repeating unit represented by the above formula (1). 2)) It is preferred that ≧ 0.05. Further, from the viewpoints of solubility and abrasion resistance of the polyester resin, preferably 0.40 ≧ (2) / ((1) + (2)) ≧ 0.08, more preferably 0.35. ≧ (2) / ((1) + (2)) ≧ 0.10.

The viscosity average molecular weight (Mv) of the polyester resin is usually 10,000 or more, and preferably 20,000 or more from the viewpoint of mechanical strength. Further, it is usually 200,000 or less, and preferably 150,000 or less from the viewpoint of applicability.
The amount of the carboxylic acid chloride group present at the terminal of the polyester resin is usually 0.1 μeq / g or less, preferably 0.05 μeq / g or less. If the amount of the terminal carboxylic acid chloride group exceeds the above range, storage stability when the polyester resin is used as a coating solution for an electrophotographic photoreceptor tends to decrease.

The carboxylic acid value of the polyester resin is preferably 300 μeq / g or less, more preferably 150 μeq / g or less. If the carboxylic acid value exceeds 300 μeq / g, the electrical properties of the photoreceptor tend to deteriorate, and further, the storage stability when the resin is dissolved in a solvent to form a coating solution tends to decrease. .
The amount of the OH group present at the terminal of the polyester resin is usually 200 μeq / g or less, preferably 100 μeq / g or less. If the amount of terminal OH groups exceeds the above range, the electrical properties when the polyester resin is used as an electrophotographic photosensitive member may be deteriorated.

The total nitrogen content (TN content) contained in the polyester resin is preferably 500 ppm or less, more preferably 300 pp or less, and particularly preferably 150 ppm or less. If the total nitrogen amount exceeds 500 ppm, the electric characteristics may be deteriorated.
The amount of the free divalent carboxylic acid contained in the polyester resin is not particularly limited, but is preferably 50 ppm or less, more preferably 10 ppm or less. When the content of the free divalent carboxylic acid exceeds 50 ppm, the electrical characteristics of the photoreceptor may be deteriorated or a foreign substance may appear in image evaluation. From the viewpoint of the electrical and image characteristics of the photoreceptor, the smaller the amount of free dicarboxylic acid, the better. However, from the viewpoint of the stability of the polyester resin, the amount is preferably 0.01 ppm or more, and more preferably 0.1 ppm or more. Is particularly preferred.

  The amount of the free dihydric phenol contained in the polyester resin is not particularly limited, but is preferably 100 ppm or less, more preferably 50 ppm or less. If it exceeds 100 ppm, foreign matters may be generated depending on the deterioration and coloring of the electric properties and the solvent used. From the viewpoint of the electrical characteristics of the photoreceptor, the smaller the amount of free dihydric phenol, the better. However, from the viewpoint of simplicity of production, the amount is preferably 0.001 ppm or more, particularly preferably 0.01 ppm or more.

製造 Method of manufacturing polyester resin≫
Next, a method for producing a polyester resin will be described. The production method includes a step of reacting a dihydric phenol represented by the formula (4-1) with a dicarboxylic acid chloride represented by the formula (5) to obtain an ester oligomer; It comprises a step of reacting the dihydric phenol represented by (4-2) to obtain a polyester resin. Examples of the method for producing the polyester resin include a solution polymerization method, a polymerization method combining a solution polymerization method and an interfacial polymerization method, or an interfacial polymerization method.

  When producing a polyester for an electrophotographic photosensitive member, it is generally produced by an interfacial polymerization method. However, when a monomer that is easily oxidized in an aqueous alkaline solution such as hydroquinone or a dihydric phenol having an ester bond and is easily hydrolyzed is used as a monomer, in the interfacial polymerization method, the monomer is used in an aqueous solution. When it becomes a salt, it is quickly oxidized to quinone, or from the viewpoint of preventing the ester bond from being rapidly hydrolyzed by a nucleophile such as a hydroxide ion, a solution polymerization method or a solution polymerization method. The polymerization method is preferably a combination of an interfacial polymerization method. From the viewpoint of simplicity of production, a solution polymerization method is particularly preferred. Hereinafter, an example of a method for producing a polyester resin by a solution polymerization method will be described.

<Production method by solution polymerization method>
In the case of production by a solution polymerization method, for example, a dihydric phenol compound and a divalent carboxylic acid chloride compound for deriving a divalent group represented by X ¹ in the above formula (1) are dissolved in a solvent, and triethylamine or the like is dissolved. After adding a base and forming an ester oligomer in the reaction system, a dihydric phenol compound for deriving a divalent group represented by X ² of the above formula (2) is added into the same reaction vessel, and the base is further added. By adding the polyester resin, a polyester resin can be obtained in one pot. The polymerization temperature is preferably in the range of −10 ° C. to 40 ° C., and the polymerization time is preferably in the range of 0.5 hour to 10 hours from the viewpoint of productivity. After completion of the polymerization, the polyester resin dissolved in the organic phase is washed and recovered to obtain the desired polyester resin. When Y ¹ and Y ² are different, Y ¹ and Y ² may be contained in the ester oligomer, or after the production of the ester oligomer containing Y ¹ , the dicarboxylic acid chloride monomer corresponding to Y ² and the above formula (2) a dihydric phenol compound that induces a divalent group represented by X ² in may contain the polyester resin by adding.

<Production method combining solution polymerization method and interfacial polymerization method>
In the case of a polymerization method in which the solution polymerization method and the interfacial polymerization method are combined, for example, a divalent phenol compound and a divalent carboxylic acid chloride compound that induce a divalent group represented by X ¹ in the formula (1) may be used. After dissolving in a solvent and adding a base such as triethylamine to obtain an ester oligomer (solution polymerization), a dihydric phenol compound for deriving a divalent group represented by X ² in the formula (2) is converted to an aqueous alkali solution. And a solution of a halogenated hydrocarbon and an aromatic hydrocarbon in which the ester oligomer and the dicarboxylic acid chloride compound are dissolved. At this time, a quaternary ammonium salt or a quaternary phosphonium salt can be used as a catalyst. The polymerization temperature is preferably in the range of 0 ° C to 40 ° C, and the polymerization time is preferably in the range of 2 hours to 20 hours from the viewpoint of productivity. After completion of the polymerization, the aqueous phase and the organic phase are separated, and the polymer dissolved in the organic phase is washed and recovered by a known method to obtain a target resin.

Since the dihydric phenol compound for deriving the divalent group represented by X ¹ in the above formula (1) is excellent in solubility, when it is combined with a poorly soluble dihydric phenol by passing through an ester oligomer comprising the same. However, a polyester resin having high solubility and excellent transparency is produced, and the obtained polyester resin can be applied to a coating film.
On the other hand, with a dicarboxylic acid chloride in the same reaction vessel a dihydric phenol to induce a divalent group represented by X ¹ from the beginning of the dissoluble poor dihydric phenol without going through the ester oligomer (1) When reacted, a poorly soluble dihydric phenol and dicarboxylic acid chloride reactant precipitate in the reaction solution, so that insoluble matter remains in the obtained polyester resin. Therefore, the coating liquid of the polyester resin becomes cloudy, and the resulting coating film may become cloudy or the surface of the coating film may become uneven. In addition, since the acid chloride terminal and the phenol terminal remain in the insoluble matter, the electrical characteristics of the obtained coating film may be deteriorated. In particular, in solution polymerization, this precipitation becomes remarkable. In the case of interfacial polymerization, even a divalent phenol having poor solubility becomes an alkali salt and dissolves in an aqueous solution, so that the possibility of precipitation during the process is reduced.

  The amount of the residual dicarboxylic acid chloride monomer in the ester oligomer satisfies the condition of the following formula (6).

The residual dicarboxylic acid chloride monomer indicates the amount of dicarboxylic acid chloride monomer remaining in the ester oligomer. The charged dicarboxylic acid chloride monomer indicates the amount of dicarboxylic acid chloride monomer initially charged to produce an ester oligomer. It should be noted that the case where the dicarboxylic acid chloride monomer is added after the production of the ester oligomer is also within the scope of the present invention as long as the formula (6) is satisfied. That is, the amount is calculated by adding the amount of the ester oligomer to the remaining dicarboxylic acid chloride monomer and the charged dicarboxylic acid chloride monomer after the ester oligomer is produced.
The amount of the residual dicarboxylic acid chloride monomer in the ester oligomer satisfies the condition of the formula (6), but from the viewpoint of the solubility of the produced polyester resin, the amount of the residual dicarboxylic acid chloride monomer is 0.1 in the formula (6). It is preferably 18 or less, more preferably 0.16 or less. These values can be measured by the method described in the example [Measurement of residual acid chloride monomer in ester oligomer]. Further, the amount of the residual dicarboxylic acid chloride monomer in the ester oligomer can be set to a specific range by adjusting, for example, the amount of the base used to the range described later.

Table case, charging ratio of dihydric phenol compound and dicarboxylic acid chloride to induce a divalent group represented by X ¹ in the (1), by the formula (4-1) for producing the ester oligomer It is preferable that the charged molar ratio of the dihydric phenol to be prepared and the dicarboxylic acid chloride represented by the formula (5) satisfies the following formula.

The molar ratio of dihydric carboxylic acid chloride to dihydric phenol is 1.05: 1 to 1.8: 1. From the viewpoint of abrasion resistance when contained in the photoreceptor, 1.08 or more is more preferred, and 1.1 or more is even more preferred. From the viewpoint of solubility of the resin, 1.6 or less is more preferable, and 1.55 or less is still more preferable.
As the base used in the solution polymerization method, for example, triethylamine, tripropylamine, tributylamine, N, N-diisopropylethylamine, N, N-dipropylethylamine, N, N-diethylmethylamine, N, N-dimethylethylamine , N, N-dimethylbutylamine, N, N-dimethylisopropylamine, N, N-diethylisopropylamine, N, N, N ', N'-tetramethyldiethylamine, 1,4-diazabicyclo [2,2,2] Examples include tertiary amines such as octane, pyridines such as pyridine and 4-methylpyridine, and organic bases such as 1,8-diazabicyclo [5.4.0] -7-undecene. The base is not particularly limited as long as it is a base such as a phosphazene base or an inorganic base used in an esterification reaction. Among these bases, triethylamine, N, N-dipropylethylamine, N, N-diethylmethylamine, and pyridine are preferable from the viewpoint of the reactivity of the esterification reaction and the convenience of availability. Triethylamine is particularly preferred from the viewpoint of easy removal in the above.

  When an ester oligomer is produced, the amount of the base used is usually 0.50 equivalent or more, preferably 0.60 equivalent or more, based on the carboxylic acid chloride group used for the production of the ester oligomer. On the other hand, it is usually 0.95 equivalent or less, preferably 0.90 equivalent or less. Further, in order to prevent unnecessary decomposition of the acid chloride, the amount is preferably 1.1 equivalent or less based on the phenolic hydroxyl group used. On the other hand, in the case of producing a polyester resin, it is usually more preferably 1.01 equivalent or more with respect to the carboxylic acid chloride group used in the reaction, and more preferably 1.05 equivalent or more to promote the polymerization reaction promptly. In addition, the equivalent is usually 2 times or less, preferably 1.8 times or less in order to prevent the decomposition of the formed ester bond and to reduce the residual base.

Solvents used in the solution polymerization method include dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, chlorobenzene, halogenated hydrocarbon compounds such as dichlorobenzene, toluene, anisole, aromatic hydrocarbon compounds such as xylene, Hydrocarbon compounds such as cyclohexane and methylcyclohexane; ether compounds such as tetrahydrofuran, tetrahydropyran, 1,4-dioxane and 1,3-dioxolan; ester compounds such as ethyl acetate, methyl benzoate and benzyl acetate; N, N-dimethyl Amide compounds such as formamide and N, N-dimethylacetamide, and the like. Further, pyridine may be used as a base and a solvent. Among these, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydrofuran, N, N-dimethylformamide, and pyridine are preferable from the viewpoint of the solubility of the monomer and the resulting oligomer and the reactivity of the esterification reaction. Further, dichloromethane is particularly preferred from the viewpoint of cleaning efficiency and electrical characteristics.

  In the case of producing a polyester resin by a solution polymerization method, the ratio of all dihydric phenols to all dihydric carboxylic acid chlorides is determined from the viewpoint of production of a high molecular weight polyester resin and control of terminal groups: all dihydric phenols: total dihydric phenols. The carboxylic acid chloride is preferably in a molar ratio of 1: 0.95 to 1: 1.05, more preferably 1: 0.99 to 1: 1.01, and particularly preferably 1: 0.992 to 1: 1.008. is there.

In producing the polyester resin, 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, pentyl Alkylphenols such as phenol, hexylphenol, octylphenol, nonylphenol, 2,6-dimethylphenol derivatives, and 2-methylphenol derivatives; monofunctional phenols such as o, m, p-phenylphenol; acetate chloride, butyric chloride, octyl Examples include monofunctional acid halides such as acid chloride, benzoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, benzenephosphonyl chloride, and substituted products thereof. Further, monofunctional aliphatic alcohols such as methanol, ethanol, propanol and the like, and monofunctional alcohols having acrylics such as 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate and 2-hydroxy methacrylate, 1H, 1H, 2H, 2H- Examples thereof include monofunctional alcohols having a perfluoroalkyl such as tridecafluoro-1-n-octanol, 1H, 1H, 2H, 2H-heptadecafluoro-1-decanol, and monofunctional alcohols having a siloxane. Among these molecular weight regulators, o, m, p- (tert-butyl) phenol, 2,6-dimethylphenol derivative, 2-methylphenol are preferable because of high molecular weight controllability and solution stability. It is a derivative. Particularly preferred are p- (tert-butyl) phenol, 2,3,6-trimethylphenol and 2,3,5-trimethylphenol.

  In order to prevent oxidation of the dihydric phenol, an antioxidant can be added during the polymerization reaction or the washing solution. Examples of the antioxidant include sodium sulfite, hydrosulfite (sodium hyposulfite), sulfur dioxide, potassium sulfite, sodium hydrogen sulfite, and the like. Among these, hydrosulfite is particularly preferred from the viewpoint of the effect of preventing oxidation and the reduction of environmental load. The amount of the antioxidant to be used is preferably 0.01% by mass or more and 10.0% by mass or less based on all dihydric phenols. More preferably, the content is 0.1% by mass or more and 5% by mass or less.

The washing method after polymerization of the polyester resin includes, for example, washing the polyester resin solution with an aqueous alkali solution such as sodium hydroxide or potassium hydroxide; an aqueous acid solution such as hydrochloric acid, nitric acid, phosphoric acid, or the like; , Centrifugation or the like. After washing the polyester resin solution, the polyester resin is insoluble in water, precipitated in alcohol or other organic solvent, or the polyester resin solution is distilled off in warm water or a dispersion medium in which the polyester resin is insoluble, or heated, The solvent may be taken out by distilling off the solvent under reduced pressure or the like. When the solvent is taken out in the form of slurry, the solid can be taken out through a centrifuge or a filter.

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

In a production method other than the solution polymerization method, the amount of the residual dicarboxylic acid chloride monomer in the ester oligomer may satisfy the condition of the above formula (6), and the polymerization method or the interfacial polymerization method combining the solution polymerization method and the interfacial polymerization method Are also within the scope of the present invention.
≪Electrophotographic photoreceptor≫
The electrophotographic photosensitive member to which the present embodiment is applied has a photosensitive layer provided on a conductive support, and the photosensitive layer contains the polyester resin produced by the production method. As a specific configuration of the photosensitive layer, for example, a laminate in which a charge generation layer mainly containing a charge generation substance and a charge transport layer mainly containing a charge transport substance and a binder resin are laminated on a conductive support Photoreceptor; Dispersion type (single-layer type) photoreceptor having a photosensitive layer in which a charge generating substance is dispersed in a layer containing a charge transporting substance and a binder resin on a conductive support. The polyester resin is generally used for a layer containing a charge transporting substance, and is preferably used for a charge transporting layer of a laminated photoreceptor.

<Conductive support>
Although there is no particular limitation on the conductive support, for example, a metal material such as aluminum, aluminum alloy, stainless steel, copper, and nickel, or a conductive powder such as metal, carbon, and tin oxide was added to impart conductivity. A resin material, a resin, glass, paper, or the like, in which a conductive material such as aluminum, nickel, and ITO (indium tin oxide) is deposited or applied on the surface thereof, are mainly used. One of these may be used alone, or two or more thereof may be used in any combination and in any ratio. The conductive support may be in the form of a drum, sheet, belt or the like. Further, a conductive support having an appropriate resistance value may be applied on a conductive support made of a metal material for controlling conductivity and surface properties and covering defects.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after applying an anodic oxide film. When the anodic oxide coating is applied, it is preferable 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, the support may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. Further, in order to reduce the cost, it is possible to use the drawn pipe as it is without performing a cutting process.

<Undercoat layer>
An undercoat layer may be provided between the conductive support and a photosensitive layer described below in order to improve adhesion and blocking properties. As the undercoat layer, a resin or a resin in which particles of a metal oxide or the like are dispersed is used. The undercoat layer may be composed of a single layer or a plurality of layers. The undercoat layer may contain known antioxidants, pigment particles, resin particles, and the like. The film thickness is usually 0.01 μm or more, preferably 0.1 μm or more, from the viewpoint of improving the electrical properties of the electrophotographic photoreceptor, the strong exposure properties, the image properties, the repetition properties, and the applicability during production. , Usually 30 μm or less, preferably 20 μm or less.

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

In addition, various types can be used as the particle size of the metal oxide particles. Among them, the average primary particle size is preferably 10 nm or more and 100 nm or less, and particularly preferably 10 nm or more and 50 nm or less from the viewpoint of characteristics and liquid stability. preferable. This average primary particle size can be obtained from a TEM photograph or the like.
The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As the binder resin used for the undercoat layer, epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, chloride resin Cellulose esters such as vinylidene resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacryl resin, polyacrylamide resin, polyvinyl pyrrolidone resin, polyvinyl pyridine resin, water-soluble polyester resin, and nitrocellulose Resin, cellulose ether resin, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compound, zirconium The organic zirconium compound alkoxide compounds, titanyl chelate compounds, organic titanyl compounds such as titanium alkoxide compounds include known binder resins such as a silane coupling agent. These may be used alone or two or more of them may be used in any combination and in any ratio. Further, it may be used in a cured form together with a curing agent. Among them, alcohol-soluble copolymerized polyamides, modified polyamides and the like are preferable because they exhibit good dispersibility and coatability. The use ratio of the inorganic particles to the binder resin used in the undercoat layer can be arbitrarily selected, but from the viewpoint of the stability of the dispersion and the applicability, it is usually 10% by mass or more based on the binder resin. It is preferable to use it in the range of 500% by mass or less.

<Photosensitive layer>
As the type of the photosensitive layer, a charge generating substance and a charge transporting substance are present in the same layer, and a single layer type in which a charge generating substance is dispersed in a binder resin, and a charge generating layer and a charge transporting substance in which a charge generating substance is dispersed in a binder resin. A function-separated type (laminated type) comprising two layers of a charge transporting layer in which a transporting substance is dispersed in a binder resin may be mentioned, but any type may be used. As the laminated photosensitive layer, a charge-generating layer and a charge-transporting layer are sequentially laminated from the conductive support side in this order, and a reverse-laminated photosensitive layer in which a charge-transport layer and a charge-generating layer are laminated in this order. There is a photosensitive layer, and any of them can be employed. However, an orderly laminated photosensitive layer capable of exhibiting the most balanced photoconductivity is preferable.

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

  When a metal-free phthalocyanine compound or a metal-containing phthalocyanine compound is used as a charge generating substance, a photosensitive member having a high sensitivity to laser light having a relatively long wavelength, for example, a laser light having a wavelength around 780 nm can be obtained. When azo pigments such as diazo and trisazo are used, white light or laser light having a wavelength around 660 nm, or laser light having a relatively short wavelength, for example, 450 nm, laser having a wavelength around 400 nm is sufficient. A photosensitive member having a high sensitivity can be obtained.

When an organic pigment is used as the charge generating substance, a phthalocyanine pigment or an azo pigment is particularly preferable. Phthalocyanine pigments provide a highly sensitive photoreceptor to relatively long wavelength laser light, while azo pigments provide sufficient sensitivity to white light and relatively short wavelength laser light. , Each is excellent.
When using a phthalocyanine pigment as the charge generating substance, specifically, a metal such as metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum, or an oxide thereof, a halide, or water The phthalocyanines coordinated with each other, such as oxides and alkoxides, having each crystal type, and phthalocyanine dimers using an oxygen atom or the like as a bridging atom are used. In particular, titanyl phthalocyanines (other names: oxytitanium) such as X-type, τ-type nonmetal phthalocyanine, A-type (other name β-type), B-type (other name α-type), and D-type (other name Y-type) which are highly sensitive crystal forms Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, hydroxyindium phthalocyanine, chlorogallium phthalocyanine such as II type, hydroxygallium phthalocyanine such as V type, μ-oxo-gallium phthalocyanine dimer such as G type and I type, II type etc. Are suitable. The .mu.-oxo-aluminum phthalocyanine dimer is preferred.

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

  The phthalocyanine compound may be a single compound, or a mixture of several compounds or mixed crystals. As the phthalocyanine compound or a mixed state that can be placed in a crystalline state, a mixture of the respective constituent elements may be used later, or a mixed state may be used in a phthalocyanine compound production / treatment step such as synthesis, pigmentation, and crystallization. What caused the state may be used. As such a treatment, an acid paste treatment, a grinding treatment, a solvent treatment and the like are known. In order to generate a mixed crystal state, as described in JP-A-10-48859, two kinds of crystals are mixed, mechanically crushed and made amorphous, and then converted to a specific crystal state by a solvent treatment. Method.

Although the binder resin used for the charge generation layer is not particularly limited, examples thereof include polyvinyl acetal-based resins such as polyvinyl butyral resin, polyvinyl formal resin, and partially formal or partially acetalized polyvinyl butyral resin modified with acetal or the like. Resin, polyarylate resin, polycarbonate resin, polyester resin, modified ether polyester resin, phenoxy resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polystyrene resin, acrylic resin, methacrylic resin, polyacrylamide resin, polyamide Resin, polyvinyl pyridine resin, cellulosic resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, vinyl chloride -Vinyl chloride-vinyl acetate copolymers such as vinyl acetate copolymer, hydroxy-modified vinyl chloride-vinyl acetate copolymer, carboxyl-modified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer; Insulating resin such as polymer, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, styrene-alkyd resin, silicon-alkyd resin, phenol-formaldehyde resin, poly-N-vinylcarbazole, polyvinylanthracene, and polyvinyl Organic photoconductive polymers such as perylene are exemplified. One of these binder resins may be used alone, or two or more of them may be used as a mixture in any combination.
In the charge generation layer, the compounding ratio (mass) of the binder resin and the charge generation substance is such that the charge generation substance is usually at least 10 parts by weight, preferably at least 30 parts by weight, and usually at least 1000 parts by weight based on 100 parts by weight of the binder resin. Parts by weight, preferably 500 parts by weight or less.

[Charge Transport Layer-Laminated Type]
The charge transporting layer of the laminated photoreceptor contains a charge transporting substance and usually contains a binder resin and other components used as necessary. The charge transport layer may be composed of a single layer, or may be a laminate of a plurality of layers having different constituent components or different composition ratios. The film thickness is usually 5 μm to 50 μm, preferably 10 μm to 45 μm.

The charge transport material is not particularly limited, and any material can be used. Examples of the charge transport material include electron-withdrawing materials such as aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, quinone compounds such as diphenoquinone, carbazole derivatives, indole 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 a plurality of these compounds are bonded. And electron donating substances such as polymers having a group consisting of these compounds in the main chain or side chain. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable. These charge transport materials may be used alone or in combination. Specific examples of suitable structures of the charge transporting material are shown below.

  The polyester resin produced by the above production method is preferably used as a binder resin for a charge transport layer. It is also possible to use a mixture of other resins. Examples of the resin having another structure mixed here include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride and copolymers thereof; polycarbonate resins, polyester resins, polyester polycarbonate resins, polysulfone resins, and phenoxy resins. Examples thereof include thermoplastic resins such as resins, epoxy resins, and silicone resins, various thermosetting resins, and copolymers thereof. Among these resins, a polycarbonate resin, a polyester resin, a copolymer of a polycarbonate resin and a silicone resin, and a copolymer of a polyester resin and a silicone resin are preferable. The mixing ratio of the resin having another structure to be mixed is not particularly limited, but it is usually preferable to use the resin in a range not exceeding the ratio of the polyester resin, specifically, the other structure relative to the polyester resin. Is usually 50 parts by mass or less, and from the viewpoint of abrasion resistance, the content is preferably 30 parts by mass or less.

  Specific examples of preferable structures of the resin having the other structure are shown below. These specific examples are shown for the purpose of illustration, and any binder resin may be mixed and used without departing from the spirit of the present invention.

As for the ratio between the polyester resin and the charge transport material, the charge transport material is used in a ratio of 30 parts by mass or more based on 100 parts by mass of the polyester resin. From the viewpoint of electrical characteristics, it is preferably at least 40 parts by mass. From the viewpoint of wear resistance, the amount is 200 parts by mass or less, preferably 150 parts by mass or less.
As for the ratio of the entire binder resin to the charge transport material, the charge transport material is usually used in a ratio of 10 parts by mass or more with respect to 100 parts by mass of the binder resin in the same layer. Above all, it is preferably at least 20 parts by mass from the viewpoint of reducing residual potential, and more preferably at least 30 parts by mass from the viewpoint of stability and charge mobility when used repeatedly. On the other hand, the charge transport material is usually used in a ratio of 150 parts by mass or less, and from the viewpoint of the thermal stability of the photosensitive layer, 120 parts by mass or less. Above all, the amount is preferably 100 parts by mass or less from the viewpoint of compatibility between the charge transport material and the binder resin, more preferably 80 parts by mass or less from the viewpoint of abrasion resistance, and particularly preferably 70 parts by mass or less from the viewpoint of scratch resistance.

  The charge transport layer has a well-known plasticizer, an antioxidant, an ultraviolet absorber, and an electron-attracting property in order to improve film formability, flexibility, coating properties, stain resistance, gas resistance, light resistance, and the like. Additives such as compounds, dyes, pigments and leveling agents may be included. Examples of the antioxidant include a hindered phenol compound and a hindered amine compound. Examples of dyes and pigments include various dye compounds and azo compounds.

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

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

When the amount of the charge generating substance dispersed in the single-layer type photosensitive layer is too small, sufficient sensitivity cannot be obtained, while when the amount is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. It is usually used in an amount of 0.5% by mass or more, preferably 1% by mass or more, and usually 50% by mass or less, preferably 20% by mass or less based on the whole layer type photosensitive layer.
Further, the usage ratio of the binder resin and the charge generating substance in the single-layer type photosensitive layer is such that the charge generating substance is usually at least 0.1 part by mass, preferably at least 1 part by mass, and It is 30 parts by mass or less, preferably 10 parts by mass or less.

  The thickness of the single-layer type photosensitive layer is usually 5 μm or more, preferably 10 μm or more, and usually 100 μm or less, preferably 50 μm or less. Also in this case, known plasticizers for improving film forming properties, flexibility, mechanical strength, etc., additives for suppressing residual potential, dispersion aids for improving dispersion stability, and coating properties. Leveling agents and surfactants for improvement, for example, silicone oil, fluorinated oil and other additives may be added.

<Other functional layers>
Both the laminated photoreceptor and the single-layer type photoreceptor have a photosensitive layer or each layer constituting the same for the purpose of improving film forming property, flexibility, coating property, stain resistance, gas resistance, light resistance, etc. Well-known additives such as antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, and visible light shielding agents. In addition, for the purpose of reducing frictional resistance and abrasion of the photoreceptor surface, increasing the transfer efficiency of the toner from the photoreceptor to the transfer belt and paper, and the like, a fluororesin, a silicone resin, a polyethylene resin, etc. Particles made of the above resin or particles of an inorganic compound may be contained in the surface layer. Alternatively, a layer containing these resins and particles may be newly formed as a surface layer. Further, if necessary, a layer for improving electric characteristics and mechanical characteristics, such as an intermediate layer such as a barrier layer, an adhesive layer, and a blocking layer, and a transparent insulating layer, may be provided.

<Method of forming each layer>
Each layer constituting these photoreceptors is obtained by dissolving or dispersing a substance to be contained in a solvent, and dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating, etc. on a support. Is formed by sequentially repeating the coating and drying steps for each layer according to the known method.

There is no particular limitation on the solvent or dispersion medium used for preparing the coating liquid, but specific examples include methanol, ethanol, propanol, alcohols such as 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, dimethoxyethane and the like. Ethers, esters such as methyl formate and ethyl acetate, ketones such as acetone, methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, chloroform, 1,2-dichloroethane, 1,1, Chlorinated hydrocarbons such as 2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine , Nitrogen-containing compounds such as triethylenediamine, acetonitrile, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. Among these solvents, non-halogen solvents are preferable from the viewpoint of environmental consideration, and toluene, xylene, anisole, dimethoxyethane, tetrahydrofuran, and 1,4-dioxane are particularly preferable from the viewpoint of solubility. Any of these may be used alone or in combination of two or more.

The use amount of the solvent or the dispersion medium is not particularly limited, but is appropriately determined so that the physical properties such as the solid content concentration and the viscosity of the coating solution fall within a desired range in consideration of the purpose of each layer and the properties of the selected solvent and dispersion medium. Adjustment is preferred.
For example, in the case of a single-layer photoreceptor and a charge transport layer of a function-separated type photoreceptor, the solid content of the coating solution is usually 5% by mass or more, usually 5% by mass or more, preferably 10% by mass or more. Further, it is usually in a range of 40% by mass or less, preferably 35% by mass or less. In addition, the viscosity of the coating solution is usually 10 cps or more, preferably 50 cps or more, and usually 500 cps or less, preferably 400 cps or less.

In the case of the charge generation layer of the laminated photoreceptor, the solid content of the coating solution is usually 0.1% by mass or more, preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. % Or less. The viscosity of the coating solution is usually 0.01 cps or more, preferably 0.1 cps or more, and usually 20 cps or less, preferably 10 cps or less.
Examples of the application method of the application liquid include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, a curtain coating method, and the like. It is also possible to use other known coating methods.
The coating liquid is preferably dried by touching at room temperature, and then heating and drying in a temperature range of usually 30 ° C. or more and 200 ° C. or less for 1 minute to 2 hours, still or under blowing. The heating temperature may be constant, or heating may be performed while changing the temperature during drying.

<Image forming apparatus>
Next, an embodiment of an image forming apparatus using the electrophotographic photoreceptor of the present invention (image forming apparatus of the present invention) will be described with reference to FIG. However, the embodiments are not limited to the following description, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

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

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

Hereinafter, specific embodiments of the present invention will be described in more detail with reference to Examples. However, the present invention is not intended to be limited by these Examples unless it exceeds the gist thereof.
[Measurement of residual acid chloride monomer in ester oligomer]
[Production of ester oligomer]
Production Example 1 (Production of ester oligomer (1))
1,1-bis (4-hydroxy-3-methylphenyl) ethane (hereinafter, BP-1) (8.32 g) and 2,3,5-trimethylphenol (0.085 g) were placed in a 500 mL four-necked reaction vessel purged with nitrogen. ) And diphenyl ether-4,4'-dicarboxylic acid chloride (hereinafter, AC-1) (12.83 g) were weighed and dissolved in dichloromethane (80 mL). Subsequently, a mixed solution of triethylamine (6.92 g: manufactured by Tokyo Chemical Industry) and dichloromethane (15 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and thereafter, stirring was continued for 10 minutes, thereby An ester oligomer (1) was produced in the reaction vessel.
Subsequently, methyl benzoate (6.41 g) was added to the resulting ester oligomer solution as an internal standard for acid chloride monomer measurement described below.

[Residual acid chloride monomer measurement]
The acid chloride was analyzed by HPLC after the acid chloride was converted into a stable compound by amidation. In this patent, the amidated HPLC peak is described as the acid chloride monomer peak. The implementation method is described below.
The ester oligomer (1) solution (1.25 g) is weighed and mixed in a 100 ml sample bottle containing morpholine (0.3 ml: manufactured by Tokyo Chemical Industry) and acetonitrile (50 ml: manufactured by Junsei Chemical Co., Ltd., for high performance liquid chromatography) and mixed. Was. After leaving at room temperature for 30 minutes to amidate the acid chloride site, 1 ml of this solution was weighed and mixed with 9 ml of the mobile phase used in the HPLC analysis described below. The mixed solution was filtered through a GL chromato disk 13P (GL Sciences, Inc., pore size: 0.45 μm) to remove solids, thereby preparing a sample solution.

Subsequently, the sample solution was subjected to HPLC analysis under the following conditions to obtain an acid chloride monomer peak area / methyl benzoate peak area ratio, and an acid chloride monomer amount was obtained from the following calibration curve. The amount of residual acid chromone contained in the ester oligomer (1) is shown in Table 1 below.

(HPLC measurement conditions)
Column: Inertsil ODS-3 5 ・ m 4.6mm × 150mm (GL Science)
Column temperature: 40 ° C
Mobile phase: methanol: pure water: acetic acid = 60: 40: 0.05 (vol%)
Flow rate: 1.0ml / min
Measurement time: 20min
Detection wavelength: 254nm
Sample solution injection volume: 10 l

(Creation of calibration curve)
The acid chloride monomer and methyl benzoate ratio was 100: 50, 50:50, 20:50, 10:50, 5:50, respectively.
, 3:50, 1:50, 0.5: 50, 0.1: 50 (mg), except that the samples were changed to the above-mentioned ester oligomer solution (1), respectively. By performing HPLC analysis, a calibration curve of the acid chloride monomer peak area / methyl benzoate peak area ratio was created.

Production Example 2 (Production of ester oligomer (2))
BP-1 (7.27 g), 2,3,5-trimethylphenol (0.090 g) and, hereinafter, AC-1 (12.88 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dichloromethane (80 mL). Was dissolved. Subsequently, a mixed solution of triethylamine (6.12 g) and dichloromethane (15 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and then, stirring was continued for 10 minutes, so that the reaction vessel was cooled. An ester oligomer (2) was produced. Subsequently, methyl benzoate (6.44 g) was added to the resulting ester oligomer solution.
The amount of residual acid chromone contained in the ester oligomer (2) was measured in the same manner as in Production Example 1. The results are shown in Table 1 below.

Production Example 3 (Production of ester oligomer (3))
BP-1 (6.27 g), 2,3,5-trimethylphenol (0.090 g) and, hereinafter, AC-1 (12.88 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dichloromethane (80 mL). Was dissolved. Subsequently, a mixed solution of triethylamine (5.26 g) and dichloromethane (15 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and thereafter, stirring was continued for 10 minutes, so that the reaction vessel was cooled. An ester oligomer (3) was produced. Subsequently, methyl benzoate (6.44 g) was added to the resulting ester oligomer solution.
In the same manner as in Production Example 1, the amount of residual acid chromone contained in the ester oligomer (3) was measured. The results are shown in Table 1 below.

Production Example 4 (Production of ester oligomer (4))
BP-1 (8.32 g), 2,3,5-trimethylphenol (0.085 g) and, hereinafter, AC-1 (12.83 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dichloromethane (80 mL). Was dissolved. Subsequently, a mixed solution of triethylamine (4.35 g) and dichloromethane (15 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and thereafter, stirring was continued for 10 minutes, and thereby, the reaction vessel was cooled. An ester oligomer (4) was produced. Subsequently, methyl benzoate (6.41 g) was added to the resulting ester oligomer solution.
The amount of residual acid chromone contained in the ester oligomer (4) was measured in the same manner as in Production Example 1. The results are shown in Table 1 below.

Production Example 5 (Production of ester oligomer (5))
BP-1 (5.21 g), 2,3,5-trimethylphenol (0.090 g) and, hereinafter, AC-1 (12.93 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dichloromethane (80 mL). Was dissolved. Subsequently, a mixed solution of triethylamine (4.61 g) and dichloromethane (15 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and thereafter, stirring was continued for 10 minutes, so that the reaction vessel was cooled. An ester oligomer (5) was produced. Subsequently, methyl benzoate (6.47 g) was added to the resulting ester oligomer solution.
The amount of residual acid chromone contained in the ester oligomer (5) was measured in the same manner as in Production Example 1. The results are shown in Table 1 below.

[Production of polyester resin]
Example 1 (Synthesis of Polyester Resin (1-1) 1: Ester Oligomer (1) Formulation)
After the ester oligomer was produced in the same manner as in Production Example 1, the polyester resin (1-1) was produced in the same reaction vessel. The production method is described below.
BP-1 (14.57 g), 2,3,5-trimethylphenol (0.102 g) and AC-1 (22.44 g) were weighed into a nitrogen-purged 1000 mL four-necked reaction vessel and dissolved in dichloromethane (140 mL). I let it. Subsequently, a mixed solution of triethylamine (12.17 g) and dichloromethane (35 mL) was added dropwise to the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and then the mixture was stirred for 10 minutes to form an ester oligomer. Was.

  Subsequently, 4-hydroxyphenyl 4-hydroxybenzoate (hereinafter referred to as BP-2) (3.46 g) was added into the reaction vessel. Thereafter, a mixed solution of triethylamine (3.22 g) and dichloromethane (35 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes. Stirring was continued for 0.5 hour while maintaining the reaction internal temperature at 15 to 23 ° C., followed by dilution with dichloromethane (230 mL), and further stirring for 0.5 hour. Subsequently, after further diluting with dichloromethane (230 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (490 mL), followed by washing with 0.2 N hydrochloric acid (490 mL) three times, and further washing with demineralized water (490 mL) twice.

  The washed organic layer was diluted by adding dichloromethane (300 ml), poured into methanol (4000 ml), and the resulting precipitate was taken out by filtration and dried to obtain the desired polyester resin (1-1). The viscosity average molecular weight (Mv) of the obtained polyester resin was 61,000. The structural formula of the polyester resin (1) group is shown below.

[Measurement of viscosity average molecular weight (Mv)]
The polyester resin was dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. Using a Ubbelohde capillary viscometer with a flow time t ₀ of the solvent (dichloromethane) of 136.16 seconds, the flow time t of the sample solution was measured in a thermostatic water bath set at 20.0 ° C. The viscosity average molecular weight (Mv) was calculated according to the following equation.
a = 0.438 × η _sp +1 η _sp = t / t ₀ −1
b = 100 × η _sp / C C = 6.00 (g / L)
η = b / a
Mv = 3207 × η ^1.205

Comparative Example 1 (Synthesis of polyester resin (1-2) 2: No via ester oligomer)
BP-1 (8.33 g), BP-2 (1.98 g), 2,3,5-trimethylphenol (0.059 g) and AC-1 (12.83 g) were placed in a 500 mL four-necked reaction vessel purged with nitrogen. Weighed and dissolved in dichloromethane (100 mL). Subsequently, a mixed solution of triethylamine (9.37 g) and dichloromethane (35 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C over 40 minutes. After maintaining stirring for 0.1 hour while maintaining the reaction internal temperature at 15 to 23 ° C., the mixture was diluted with dichloromethane (120 mL) and stirred for 0.5 hour. Then, after further diluting with dichloromethane (120 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (280 mL), followed by washing with 0.2 N hydrochloric acid (280 mL) three times, and further washing with demineralized water (280 mL) twice. Dichloromethane (100 ml) was added to the washed organic layer to dilute it, and the mixture was poured into methanol (2000 ml), and the obtained precipitate was taken out by filtration and dried to obtain a polyester resin (1-2). The viscosity average molecular weight (Mv) of the obtained polyester resin was 36,800.

Comparative Example 2 (Synthesis of Polyester Resin (1-3) 3: Ester Oligomer (4) Formulation)
After producing an ester oligomer with the same formulation as in Production Example 4, a polyester resin (1-3) was produced in the same reaction vessel. The production method is described below.
BP-1 (8.33 g), 2,3,5-trimethylphenol (0.059 g) and AC-1 (12.83 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dissolved in dichloromethane (80 mL). I let it. Subsequently, a mixed solution of triethylamine (4.35 g) and dichloromethane (20 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and then the mixture was stirred for 10 minutes to form an ester oligomer. Was.

Subsequently, BP-2 (1.98 g) was added into the reaction vessel. Thereafter, a mixed solution of triethylamine (5.03 g) and dichloromethane (35 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C over 20 minutes. Stirring was continued for 0.2 hours while maintaining the internal reaction temperature at 15 to 23 ° C., followed by dilution with dichloromethane (120 mL), and further stirring for 0.5 hour. Then, after further diluting with dichloromethane (120 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (280 mL), followed by washing with 0.2 N hydrochloric acid (280 mL) three times, and further washing with demineralized water (280 mL) twice.
The washed organic layer was diluted by adding dichloromethane (100 ml), poured into methanol (2000 ml), and the obtained precipitate was taken out by filtration and dried to obtain a polyester resin (1-3). The viscosity average molecular weight (Mv) of the obtained polyester resin was 45,000.

Comparative Example 3 (Synthesis of Polyester Resin (1-4) 4: Formulation of Ester Oligomer (5))
After an ester oligomer was produced in the same manner as in Production Example 5, a polyester resin (1-4) was produced in the same reaction vessel. The production method is described below.
BP-1 (5.21 g), 2,3,5-trimethylphenol (0.059 g) and AC-1 (12.83 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dissolved in dichloromethane (80 mL). I let it. Subsequently, a mixed solution of triethylamine (4.46 g) and dichloromethane (20 mL) was added dropwise to the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and then the mixture was stirred for 10 minutes to form an ester oligomer. Was.

Subsequently, BP-1 (3.12 g) and BP-2 (1.98 g) were added into the reaction vessel. Thereafter, a mixed solution of triethylamine (4.92 g) and dichloromethane (35 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes. Stirring was continued for 0.2 hours while maintaining the internal reaction temperature at 15 to 23 ° C., followed by dilution with dichloromethane (120 mL), and further stirring for 0.5 hour. Then, after further diluting with dichloromethane (120 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (280 mL), followed by washing with 0.2 N hydrochloric acid (280 mL) three times, and further washing with demineralized water (280 mL) twice.
The washed organic layer was diluted with dichloromethane (100 ml), poured into methanol (2000 ml), and the resulting precipitate was taken out by filtration and dried to obtain a polyester resin (1-4). The viscosity average molecular weight (Mv) of the obtained polyester resin was 46,500.

Example 2 (Synthesis of Polyester Resin (2-1): Ester Oligomer (2) Formulation)
After the ester oligomer was produced in the same manner as in Production Example 2, the polyester resin (2-1) was produced in the same reaction vessel. The production method is described below.
BP-1 (7.92 g), 2,3,5-trimethylphenol (0.064 g) and AC-1 (13.86 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dissolved in dichloromethane (80 mL). I let it. Subsequently, a mixed solution of triethylamine (6.64 g) and dichloromethane (20 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and thereafter, the ester oligomer was formed by continuing stirring for 10 minutes. Was.

  Subsequently, BP-2 (2.96 g) was added into the reaction vessel. Thereafter, a mixed solution of triethylamine (3.20 g) and dichloromethane (30 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C over 20 minutes. Stirring was continued for 0.5 hour while maintaining the reaction internal temperature at 15 to 23 ° C., followed by dilution with dichloromethane (120 mL), and further stirring for 0.5 hour. Then, after further diluting with dichloromethane (120 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (280 mL), followed by washing with 0.2 N hydrochloric acid (280 mL) three times, and further washing with demineralized water (280 mL) twice.

  Dichloromethane (150 ml) was added to the washed organic layer to dilute it, and the mixture was poured into methanol (2000 ml), and the obtained precipitate was taken out by filtration and dried to obtain the desired polyester resin (2-1). The viscosity average molecular weight (Mv) of the obtained polyester resin was 75,000. The structural formula of the polyester resin (2) group is shown below.

Example 3 (Synthesis of Polyester Resin (3-1) 1: Formulation of Ester Oligomer (2))
After an ester oligomer was produced in the same manner as in Production Example 2, a polyester resin (3) was produced in the same reaction vessel. The production method is described below.
BP-1 (13.89 g), 2,3,5-trimethylphenol (0.067 g) and AC-1 (24.33 g) were weighed into a nitrogen-purged 1000 mL four-necked reaction vessel and dissolved in dichloromethane (120 mL). I let it. Subsequently, a mixed solution of triethylamine (11.60 g) and dichloromethane (30 mL) was added dropwise to the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and then the mixture was stirred for 10 minutes to form an ester oligomer. Was.

  Subsequently, hydroquinone (hereinafter, BP-3) (2.71 g) was added into the reaction vessel. Thereafter, a mixed solution of triethylamine (6.13 g) and dichloromethane (50 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes. Stirring was continued for 0.5 hour while maintaining the reaction internal temperature at 15 to 23 ° C., followed by dilution with dichloromethane (230 mL), and further stirring for 0.5 hour. Then, after further diluting with dichloromethane (230 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (490 mL), followed by washing with 0.2 N hydrochloric acid (490 mL) three times, and further washing with demineralized water (490 mL) twice.

  The washed organic layer was diluted by adding dichloromethane (300 ml), poured into methanol (4000 ml), and the resulting precipitate was taken out by filtration and dried to obtain the desired polyester resin (3-1). The viscosity average molecular weight (Mv) of the obtained polyester resin was 55,000. The structural formula of the polyester resin (3) group is shown below.

Comparative Example 4 (Synthesis of polyester resin (3-2) 2: without ester oligomer)
BP-1 (6.95 g), BP-3 (1.35 g), 2,3,5-trimethylphenol (0.034 g) and AC-1 (12.17 g) were placed in a 500 mL four-neck reaction vessel purged with nitrogen. Weighed and dissolved in dichloromethane (100 mL). Subsequently, a mixed solution of triethylamine (8.87 g) and dichloromethane (35 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C over 40 minutes. After maintaining stirring for 0.1 hour while maintaining the reaction internal temperature at 15 to 23 ° C., the mixture was diluted with dichloromethane (120 mL) and stirred for 0.5 hour. Then, after further diluting with dichloromethane (120 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (280 mL), followed by washing with 0.2 N hydrochloric acid (280 mL) three times, and further washing with demineralized water (280 mL) twice. The washed organic layer was diluted by adding dichloromethane (150 ml), poured into methanol (2000 ml), and the obtained precipitate was taken out by filtration and dried to obtain a polyester resin (3-2). The viscosity average molecular weight (Mv) of the obtained polyester resin was 39,000.

Example 4 (Synthesis of polyester resin (4-1): ester oligomer (3) formulation)
After an ester oligomer was produced in the same manner as in Production Example 3, a polyester resin (4-1) was produced in the same reaction vessel. The production method is described below.
BP-1 (7.00 g), 2,3,5-trimethylphenol (0.065 g) and AC-1 (14.34 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dissolved in dichloromethane (80 mL). I let it. Subsequently, a mixed solution of triethylamine (5.87 g) and dichloromethane (20 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and thereafter, the ester oligomer was formed by continuing stirring for 10 minutes. Was.

  Subsequently, BP-3 (2.12 g) was added into the reaction vessel. Thereafter, a mixed solution of triethylamine (4.56 g) and dichloromethane (30 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes. Stirring was continued for 0.5 hour while maintaining the internal reaction temperature at 15 to 23 ° C., followed by dilution with dichloromethane (120 mL), and further stirring for 0.5 hour. Then, after further diluting with dichloromethane (120 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (280 mL), followed by washing with 0.2 N hydrochloric acid (280 mL) three times, and further washing with demineralized water (280 mL) twice.

  Dichloromethane (150 ml) was added to the washed organic layer to dilute it, and the mixture was poured into methanol (2000 ml), and the obtained precipitate was taken out by filtration and dried to obtain the desired polyester resin (4-1). The viscosity average molecular weight (Mv) of the obtained polyester resin was 57,500. The structural formula of the polyester resin (4) group is shown below.

Example 5 (Synthesis of Polyester Resin (5-1) 1: Ester Oligomer (1) Formulation)
After an ester oligomer was produced in the same manner as in Production Example 1, a polyester resin (5-1) was produced in the same reaction vessel. The production method is described below.
BP-1 (8.44 g), 2,3,5-trimethylphenol (0.119 g) and AC-1 (13.02 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dissolved in dichloromethane (80 mL). I let it. Subsequently, a mixed solution of triethylamine (7.07 g) and dichloromethane (20 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and then, the mixture was stirred for 10 minutes to form an ester oligomer. Was.

  Subsequently, 4,4'-biphenol (hereinafter, BP-4) (1.62 g) was added into the reaction vessel. Thereafter, a mixed solution of triethylamine (2.42 g) and dichloromethane (30 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C over 20 minutes. Stirring was continued for 0.5 hour while maintaining the internal reaction temperature at 15 to 23 ° C., followed by dilution with dichloromethane (90 mL), and further stirring for 0.5 hour. Subsequently, after further diluting with dichloromethane (80 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (230 mL), followed by washing with 0.2 N hydrochloric acid (230 mL) three times, and further washing with demineralized water (230 mL) twice.

  Dichloromethane (150 ml) was added to the washed organic layer to dilute it, and the mixture was poured into methanol (2000 ml), and the obtained precipitate was taken out by filtration and dried to obtain a target polyester resin (5-1). The viscosity average molecular weight (Mv) of the obtained polyester resin was 38,200. The structural formula of the polyester resin (5) group is shown below.

Comparative Example 5 (Synthesis of polyester resin (5-2) 2: without ester oligomer)
BP-1 (8.44 g), BP-4 (1.62 g), 2,3,5-trimethylphenol (0.119 g) and AC-1 (13.02 g) were placed in a 500 mL four-necked reaction vessel purged with nitrogen. Weighed and dissolved in dichloromethane (100 mL). Subsequently, a mixed solution of triethylamine (9.49 g) and dichloromethane (35 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C over 40 minutes. After keeping stirring for 0.1 hour while maintaining the reaction internal temperature at 15 to 23 ° C., the mixture was diluted with dichloromethane (85 mL) and stirred for 0.5 hour. Subsequently, after further diluting with dichloromethane (80 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (230 mL), followed by washing with 0.2 N hydrochloric acid (230 mL) three times, and further washing with demineralized water (230 mL) twice. The washed organic layer was diluted with dichloromethane (150 ml) and poured into methanol (2000 ml), and the resulting precipitate was taken out by filtration and dried to obtain a polyester resin (5-2). The viscosity average molecular weight (Mv) of the obtained polyester resin was 25,000.

Example 6 (Synthesis of polyester resin (6-1): ester oligomer (3) formulation)
After the ester oligomer was produced in the same manner as in Production Example 3, the polyester resin (6-1) was produced in the same reaction vessel. The production method is described below.
BP-1 (6.36 g), 2,3,5-trimethylphenol (0.060 g) and AC-1 (13.07 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dissolved in dichloromethane (80 mL). Let it go. Subsequently, a mixed solution of triethylamine (5.42 g) and dichloromethane (20 mL) was added dropwise to the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and thereafter, stirring was continued for 10 minutes to form an ester oligomer. Was.

  Subsequently, 4,4'-dihydroxy-3,3'-dimethylbiphenyl (hereinafter, BP-5) (3.75 g) was added into the reaction vessel. Thereafter, a mixed solution of triethylamine (4.16 g) and dichloromethane (50 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C over 20 minutes. Stirring was continued for 0.5 hour while maintaining the reaction internal temperature at 15 to 23 ° C., followed by dilution with dichloromethane (75 mL), and further stirring for 0.5 hour. Then, after further diluting with dichloromethane (75 mL), the mixture was stirred for 4 hours. Thereafter, washing was performed with demineralized water (230 mL), followed by washing with 0.2 N hydrochloric acid (230 mL) three times, and further washing with demineralized water (230 mL) twice.

  The washed organic layer was diluted by adding dichloromethane (150 ml), poured into methanol (2000 ml), and the obtained precipitate was taken out by filtration and dried to obtain the desired polyester resin (6-1). The viscosity average molecular weight (Mv) of the obtained polyester resin was 55,200. The structural formula of the polyester resin (6-1) is shown below.

Example 7 (Synthesis of polyester resin (7-1))
After the ester oligomer was produced in the same manner as in Production Example 2, the polyester resin (7-1) was produced in the same reaction vessel. The production method is described below.
BP-1 (7.63 g), 2,3,5-trimethylphenol (0.092 g) and AC-1 (13.42 g) were weighed into a 500 mL four-necked reaction vessel purged with nitrogen, and dissolved in dichloromethane (80 mL). I let it. Subsequently, a mixed solution of triethylamine (6.42 g) and dichloromethane (20 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and thereafter, stirring was continued for 10 minutes to form an ester oligomer. Was.

  Subsequently, 2,6-dihydroxynaphthalene (hereinafter, BP-6) (2.16 g) was added into the reaction vessel. Thereafter, a mixed solution of triethylamine (3.41 g) and dichloromethane (30 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C over 20 minutes. Stirring was continued for 0.5 hour while maintaining the reaction internal temperature at 15 to 23 ° C., followed by dilution with dichloromethane (90 mL), and further stirring for 0.5 hour. Then, after further diluting with dichloromethane (80 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (200 mL), followed by washing with 0.2 N hydrochloric acid (200 mL) three times, and further washing with demineralized water (200 mL) twice.

  The washed organic layer was diluted by adding dichloromethane (150 ml), poured into methanol (2000 ml), and the obtained precipitate was taken out by filtration and dried to obtain the desired polyester resin (7-1). The viscosity average molecular weight (Mv) of the obtained polyester resin was 40,700. The structural formula of the polyester resin (7-1) is shown below.

Example 8 (Synthesis of polyester resin (8-1))
A polyester resin (8-1) was obtained in the same manner as in Example 7 except that 2,6-dihydroxynaphthalene in Example 7 was replaced with 2,7-dihydroxynaphthalene (hereinafter referred to as BP-7). The viscosity average molecular weight (Mv) of the obtained polyester resin was 35,500. The structural formula of the polyester resin (8-1) is shown below.

Example 9 (Synthesis of polyester resin (9-1))
After an ester oligomer was produced in the same manner as in Production Example 1, a polyester resin (9-1) was produced in the same reaction vessel. The production method is described below.
Bis (4-hydroxy-3-methylphenyl) methane (hereinafter referred to as BP-8) (9.03 g), 2,3,5-trimethylphenol (0.060 g) and AC- 1 (13.13 g) was weighed and dissolved in dichloromethane (75 mL). Subsequently, a mixed solution of triethylamine (7.20 g) and dichloromethane (20 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C. over 20 minutes, and thereafter, the ester oligomer was formed by continuing stirring for 10 minutes. Was.

  Subsequently, BP-1 (1.01 g) was added into the reaction vessel. Thereafter, a mixed solution of triethylamine (2.41 g) and dichloromethane (80 mL) was dropped into the reaction vessel cooled to 5 to 15 ° C over 20 minutes. Stirring was continued for 0.2 hours while maintaining the internal reaction temperature at 15 to 23 ° C., followed by dilution with dichloromethane (50 mL), and further stirring for 0.5 hour. Subsequently, after further diluting with dichloromethane (70 mL), stirring was performed for 4 hours. Thereafter, washing was performed with demineralized water (210 mL), followed by washing with 0.2 N hydrochloric acid (210 mL) three times, and further washing with demineralized water (210 mL) twice.

  The washed organic layer was diluted by adding dichloromethane (150 ml), poured into methanol (2000 ml), and the obtained precipitate was taken out by filtration and dried to obtain the desired polyester resin (9-1). The viscosity average molecular weight (Mv) of the obtained polyester resin was 60,100. The structural formula of the polyester resin (9-1) is shown below.

Example 10 (Synthesis of polyester resin (10-1))
Example 10 was carried out in the same manner as in Example 10 except that bis (4-hydroxy-3-methylphenyl) methane in Example 10 was replaced with 1,1-bis (4-hydroxyphenyl) ethane (hereinafter, BP-9). A polyester resin (10-1) was obtained. The viscosity average molecular weight (Mv) of the obtained polyester resin was 56,200. The structural formula of the polyester resin (10-1) is shown below.

<Appearance of polyester THF solution>
After 100 parts by mass of the polyester resins produced in Examples 1 to 10 and Comparative Examples 1 to 5 were put in a transparent sample bottle, they were dissolved in 660 parts by mass of a tetrahydrofuran solvent, and the appearance of the solution was confirmed. ○ represents a clear solution, and × represents a cloudy solution. The results are shown in Table 2 below.

  From the results shown in Table 2, it can be seen that a polyester resin having excellent solubility can be obtained by setting the amount of the residual acid chloride monomer in the ester oligomer within the range of the present patent via the ester oligomer. On the other hand, when the solution does not pass through the ester oligomer or when the amount of the residual acid chloride monomer in the ester oligomer is larger than the range in the present invention, an insoluble oligomer is formed, and the solution becomes cloudy.

<Preparation of photoreceptor sheet>
[Example 11]
10 parts by mass of oxytitanium phthalocyanine and 150 parts by mass of 4-methoxy-4-methyl-2-pentanone were mixed and pulverized and dispersed by a sand grind mill to produce a pigment dispersion. In addition, oxytitanium phthalocyanine has a Bragg angle (2θ ± 0.2) of 9.3 °, 10.6 °, 13.2 °, 15.1 °, 15.7 °, 16.2 ° in X-ray diffraction by CuKα ray. Strong diffraction peaks are shown at 1 °, 20.8 °, 23.3 °, 26.3 °, and 27.1 °.

  To this pigment dispersion, 50 parts by mass of a 5% by mass 1,2-dimethoxyethane solution of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: Denka Butyral @ 6000C), and a phenoxy resin (trade name, manufactured by Union Carbide Co., Ltd.) 50 mass parts of a 5 mass% 1,2-dimethoxyethane solution of PKHH) was added, and an appropriate amount of 1,2-dimethoxy ethane was further added to prepare a coating solution for forming a charge generation layer having a solid concentration of 4.0%. did. This charge generation layer forming coating solution was applied on a polyethylene terephthalate sheet having a surface thereof subjected to aluminum evaporation so that the film thickness after drying was 0.4 μm, and dried to form a charge generation layer.

  Next, as a charge transport material, a mixture (CTM-1) produced by the method described in Example 1 of JP-A-2002-080432, comprising a group of geometrical isomers having the following structure as a main component: ), 50 parts by mass of the polyester resin (1-1) produced in Example 1, 8 parts by mass of an antioxidant (Irganox 1076), 0.05 parts by mass of silicone oil as a leveling agent, and tetrahydrofuran. It was mixed with 640 parts by mass of a mixed solvent with toluene (80% by mass of tetrahydrofuran, 20% by mass of toluene) to prepare a coating solution for forming a charge transport layer.

This charge transport layer forming coating solution is applied on the above-mentioned charge generation layer using an applicator so that the film thickness after drying is 25 μm, and dried at 125 ° C. for 20 minutes to form a charge transport layer. Then, a photoreceptor sheet was prepared.
[Example 12]
A photoconductor sheet was produced in the same manner as in Example 11, except that the polyester resin (1) was changed to the polyester resin (3-1) produced in Example 3.

Example 13
A photoreceptor sheet was produced in the same manner as in Example 11, except that the polyester resin (1) was changed to the polyester resin (5-1) produced in Example 5.
[Example 14]
A photoconductor sheet was prepared in the same manner as in Example 11, except that the polyester resin (1) was changed to the polyester resin (6-1) produced in Example 6.

[Example 15]
A photoreceptor sheet was prepared in the same manner as in Example 11, except that the polyester resin (1) was changed to the polyester resin (7-1) produced in Example 7.
[Example 16]
A photoconductor sheet was prepared in the same manner as in Example 11, except that the polyester resin (1) was changed to the polyester resin (8-1) produced in Example 8.

[Example 17]
A photoconductor sheet was prepared in the same manner as in Example 11, except that the polyester resin (1-1) was changed to the polyester resin (9) produced in Example 9.
[Comparative Example 6]
A photoreceptor sheet was prepared in the same manner as in Example 11, except that the polyester resin (1-2) was changed to the polyester resin (1) produced in Comparative Example 1.

[Comparative Example 7]
A photoconductor sheet was produced in the same manner as in Example 11, except that the polyester resin (1-3) was changed to the polyester resin (1) produced in Comparative Example 2.
[Reference Example 1]
Except that the polyester resin (1-1) was changed to a polyester resin (11) (viscosity average molecular weight 36,200) having the following structure, which was produced by the method described in Example 6 of JP-A-2006-53549. A photoreceptor sheet was prepared in the same manner as in Example 1.

[Surface state of charge transport layer]
The surface states of the photoreceptor sheets prepared in Examples 11 to 17, Comparative Examples 6 and 7, and Reference Example 1 were visually checked. The case where there was no unevenness on the surface was visually evaluated as ○, and the case where the surface had unevenness was evaluated as ×. If there are irregularities that can be visually recognized, an image defect occurs when printed.
[Electrical characteristics evaluation]
The measurement was performed using the photoreceptor sheets prepared in Examples 11 to 17, Comparative Examples 6 and 7, and Reference Example 1. Using an electrophotographic property evaluation device (basic and application of electrophotographic technology, edited by the Electrophotographic Society, Corona Co., pp. 404-405) manufactured according to the electrophotographic society measurement standard, the photosensitive member sheet was made of an aluminum drum. Was formed into a cylindrical shape, and conduction was established between the aluminum drum and the aluminum substrate of the photoreceptor. In this evaluation apparatus, the drum is rotated at a constant rotation speed, and a cycle of charging, exposure, potential measurement, and static elimination can be performed. As an electrical property evaluation, a potential holding ratio (DDR) after being charged to -700 V and left for 5 seconds was measured (%). The higher the potential holding ratio is, the more stable the photoreceptor is, and image defects such as fog are unlikely to occur. The measurement was performed at a temperature of 25 ° C. and a relative humidity of 50% (N / N). The results are shown in Table-3.

[Wear test]
The photoreceptor film was cut into a circle having a diameter of 10 cm, and abrasion was evaluated using a Taber abrasion tester (manufactured by Toyo Seiki Co., Ltd.). The test conditions were measured by comparing the mass before and after the test with the abrasion wheel CS-10F under the atmosphere of 25 ° C. and 50% RH under a load of 500 g after rotating 1000 times. The smaller the value, the better the wear resistance. The results are shown in Table-4.

  From the above, it has been clarified that the use of the polyester resin produced according to the present invention can provide a clean coating film free of defects and can provide an electrophotographic photoreceptor excellent in electric characteristics and abrasion resistance.

Reference Signs List 1 photoconductor 2 charging device (charging roller)
Reference Signs List 3 exposure device 4 developing device 5 transfer device 6 cleaning device 7 fixing device 41 developing tank 42 agitator 43 supply roller 44 developing roller 45 regulating member 71 upper fixing member (pressure roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper

Claims (7)

A method for producing a polyester resin containing a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), wherein a dihydric phenol represented by the following formula (4-1) and Reacting a dicarboxylic acid chloride represented by the formula (5) to obtain an ester oligomer, and reacting the ester oligomer with a dihydric phenol represented by the following formula (4-2) to obtain a polyester resin A process for producing a polyester resin, comprising the step of: a residual amount of a dicarboxylic acid chloride monomer represented by the following formula (5) in the ester oligomer satisfying the following formula (6).

(In the formula (1), X ¹ is a divalent group represented by the following formula (3), and Y ¹ and Y ² are each independently a divalent group. In the formula (2), X ² is a group containing a divalent aromatic, provided that Y is
¹ may be the same as Y ² and X ² is not the same as X ¹ . )

(In the formula (3), R ¹ and R ² each independently have a hydrogen atom, an alkyl group which may have a substituent having 1 to 20 carbon atoms, and a substituent having 1 to 20 carbon atoms. Represents an optionally substituted alkoxyl group or an aromatic group optionally having a substituent having 1 to 20 carbon atoms, wherein n ¹ and n ² each represent an integer of 0 to ^4. R ³ and R ⁴ represent Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic group which may have a substituent having 1 to 20 carbon atoms, provided that R ³ and R ⁴ are bonded to each other; (A ring may be formed.)

In the step of obtaining the ester oligomer, the charged molar ratio of the dihydric phenol represented by the formula (4-1) and the dicarboxylic acid chloride represented by the formula (5) is as follows:

2. The method for producing a polyester resin according to claim 1, wherein 3. In the formula (2), X ² is a group containing at least one kind of divalent aromatic selected from the following formulas (7) to (10). 4. Method for producing a polyester resin.

(In the formula (7), R ⁵ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxyl group having 1 to 20 carbon atoms which may have a substituent, 1-20 substituents aromatic group which may have a, or a halogen group, n ³ is an integer of 0-4.)

(In the formula (8), R ⁶ represents a hydrogen atom, an alkyl group which may have a substituent having 1 to 20 carbon atoms, an alkoxyl group which may have a substituent having 1 to 20 carbon atoms, 1-20 substituents aromatic group which may have a, or a halogen group, n ⁴ represents an integer of 0-6.)

(In the formula (9), R ⁷ and R ⁸ each independently represent a hydrogen atom, an alkyl group which may have a substituent having 1 to 20 carbon atoms, or a substituent having 1 to 20 carbon atoms. An alkoxyl group which may be
Represents an aromatic group which may have a substituent having 1 to 20 carbon atoms or a halogen group, and represents n ⁵ , n
⁶ represents an integer of 0 to 4; W ¹ represents a single bond, an oxygen atom, a sulfur atom, or a methylene group. )

(In the formula (10), Ar ¹ and Ar ² each independently represent an arylene group which may have a substituent having 6 to 16 carbon atoms. Z is an arylene which may have a substituent. Represents an alkylene group having 2 to 20 carbon atoms which may have a group or a substituent, and s represents an integer of 0 or 1.) The content of the repeating unit represented by the formula (2) in the polyester resin is determined by the formula (1)
0.45 ≧ (2) / ((1) + (2)) ≧ 0.0 in molar ratio with the repeating unit represented by
5. The method for producing a polyester resin according to claim 1, wherein the method satisfies 5. In the formulas (1) and (2), Y ¹ and Y ² are divalent groups represented by the following formula (11). The method for producing a polyester resin according to the above.

(In the formula (11), Ar ³ and Ar ⁴ each independently represent an arylene group which may have a substituent. Z is a single bond, an oxygen atom, a sulfur atom, or a formula (12) Structure or formula (
It represents a divalent group having a structure represented by 13). R ⁹ and R ¹⁰ in the formula (12) each independently represent a hydrogen atom, an alkyl group, an aryl group, or a cycloalkylidene group formed by combining R ⁹ and R ¹⁰ . Further, in the formula (13), R ¹¹ represents an alkylene group, an arylene group, or a group represented by the formula (14). In the formula (14), R ¹² and R ¹³ each independently represent an alkylene group, and Ar ⁵ represents an arylene group. k represents an integer of 0 to 5. )

The method for producing the polyester resin is a solution polymerization method.
The method for producing a polyester resin according to any one of the above. A method for producing an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support , comprising:
Item 7. A polyester resin is produced by the method according to any one of Items 1 to 6, wherein the polyester resin
A method for producing an electrophotographic photoreceptor, comprising forming a photosensitive layer using

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