JP2019077844A - Polyarylate resin and electrophotographic photoreceptor - Google Patents

Abstract

To provide a polyarylate resin capable of increasing abrasion resistance of an electrophotographic photoreceptor when contained in a photosensitive layer.SOLUTION: The polyarylate resin at least comprises a repeating unit represented by general formula (1), a repeating unit represented by chemical formula (2), and a repeating unit represented by chemical formula (3).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polyarylate resin and an electrophotographic photosensitive member.

  The electrophotographic photosensitive member is used as an image carrier in an electrophotographic image forming apparatus (for example, a printer or a multifunction peripheral). The electrophotographic photosensitive member comprises a photosensitive layer. As the electrophotographic photosensitive member, for example, a single-layer type electrophotographic photosensitive member and a laminated type electrophotographic photosensitive member are used. The single-layer type electrophotographic photosensitive member comprises a single-layer photosensitive layer having a charge generation function and a charge transport function. The multi-layered electrophotographic photosensitive member includes a photosensitive layer including a charge generation layer having a charge generation function and a charge transport layer having a charge transport function.

  Patent Document 1 describes an electrophotographic photosensitive member having a photosensitive layer. The binder resin of the photosensitive layer contains a specific polyarylate structure.

Unexamined-Japanese-Patent No. 2003-322982

  However, the electrophotographic photosensitive member described in Patent Document 1 is insufficient in terms of abrasion resistance.

  The present invention has been made in view of the above problems, and an object thereof is to provide a polyarylate resin capable of improving the abrasion resistance of an electrophotographic photosensitive member when it is contained in a photosensitive layer. Another object of the present invention is to provide an electrophotographic photosensitive member excellent in abrasion resistance.

The polyarylate resin of the present invention comprises at least the repeating unit represented by the general formula (1), the repeating unit represented by the chemical formula (2), and the repeating unit represented by the chemical formula (3). The ratio n ₁ / n ₂ of the number n ₁ of repeating units represented by the general formula (1) to the number n ₂ of repeating units represented by the chemical formula (2) is 1.0 or more.

In the above general formula (1), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, R ³ represents a methyl group, and R ⁴ represents a hydrogen atom or an alkyl group having 2 or 3 carbon atoms. . Alternatively, in the general formula (1), R ¹ and R ² each represent a methyl group, and R ³ and R ⁴ are bonded to each other to represent a cycloalkylidene group having 5 or 6 carbon atoms.

  The electrophotographic photosensitive member of the present invention comprises a conductive substrate and a photosensitive layer. The photosensitive layer contains a charge generating agent, a hole transporting agent, and a binder resin. The binder resin includes the above-described polyarylate resin.

  The polyarylate resin of the present invention can improve the abrasion resistance of the electrophotographic photosensitive member when it is contained in the photosensitive layer. In addition, the electrophotographic photosensitive member of the present invention is excellent in abrasion resistance.

Each of (a), (b) and (c) is a cross-sectional view showing an example of the electrophotographic photosensitive member, and the electrophotographic photosensitive member contains the polyarylate resin according to the embodiment of the present invention. (A), (b) and (c) are each a sectional view showing another example of the electrophotographic photosensitive member, and the electrophotographic photosensitive member contains the polyarylate resin according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited at all to the following embodiments. The present invention can be implemented with appropriate modifications within the scope of the object of the present invention. In addition, although description may be suitably abbreviate | omitted about the location where description overlaps, the summary of invention is not limited. Hereinafter, “system” may be added after the compound name to generically generically refer to the compound and its derivative. Moreover, when a "system" is attached after a compound name and it represents a polymer name, it means that the repeating unit of a polymer originates in a compound or its derivative (s).

  Hereinafter, an alkyl group having 1 to 8 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, and 1 carbon atom The alkoxy group having 4 or more and the cycloalkane having 5 or more and 7 or less carbon atoms have the following meanings unless otherwise specified.

  The alkyl group having 1 to 8 carbon atoms, the alkyl group having 1 to 6 carbon atoms and the alkyl group having 1 to 4 carbon atoms are each linear or branched and unsubstituted. As an alkyl group having 1 to 8 carbon atoms, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl Groups, neopentyl group, 1,2-dimethylpropyl group, hexyl group, heptyl group and octyl group. Examples of the alkyl group having 1 to 6 carbon atoms are groups having 1 to 6 carbon atoms among the groups described as the examples of the alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms are groups having 1 to 4 carbon atoms among the groups described as the examples of the alkyl group having 1 to 8 carbon atoms.

  The alkoxy group having 1 to 8 carbon atoms and the alkoxy group having 1 to 4 carbon atoms are each linear or branched and unsubstituted. As an alkoxy group having 1 to 8 carbon atoms, for example, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentoxy group, Isopentoxy group, neopentoxy group, hexyloxy group, heptyloxy group and octyloxy group can be mentioned. Examples of the alkoxy group having 1 to 4 carbon atoms are groups having 1 to 4 carbon atoms among the groups described as the examples of the alkoxy group having 1 to 8 carbon atoms.

  The cycloalkane having 5 to 7 carbon atoms is unsubstituted. Examples of the cycloalkane having 5 to 7 carbon atoms include cyclopentane, cyclohexane and cycloheptane.

<Polyarylate resin>
The present embodiment relates to a polyarylate resin. The polyarylate resin of the present embodiment contains at least the repeating unit represented by the general formula (1), the repeating unit represented by the chemical formula (2), and the repeating unit represented by the chemical formula (3). The ratio n ₁ / n ₂ of the number n ₁ of repeating units represented by General Formula (1) to the number n ₂ of repeating units represented by Chemical Formula (2) is 1.0 or more.

In the general formula (1), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and R ³ represents a methyl group, and R ⁴ represents a hydrogen atom or an alkyl group having 2 or 3 carbon atoms. Represent. Alternatively, in the general formula (1), R ¹ and R ² each represent a methyl group, and R ³ and R ⁴ are bonded to each other to represent a cycloalkylidene group having 5 or 6 carbon atoms.

Hereinafter, the repeating unit represented by the general formula (1), the repeating unit represented by the chemical formula (2), and the repeating unit represented by the chemical formula (3) are respectively a repeating unit (1) and a repeating unit (2 And the repeating unit (3). Further, the ratio n ₁ / n ₂ of the number n ₁ of the repeating units (1) to the number n ₂ of the repeating units (2) at least including the repeating units (1), the repeating units (2) and the repeating units (3) The polyarylate resin which is more than 1.0 may be described as polyarylate resin (PA).

  The polyarylate resin (PA) of the present embodiment can improve the abrasion resistance of an electrophotographic photosensitive member (hereinafter sometimes referred to as a photosensitive member) when it is contained in a photosensitive layer. The reason is presumed as follows.

  First, polyarylate resin (PA) contains repeating unit (2) and repeating unit (3). Thereby, the abrasion resistance of the photosensitive member can be improved.

Second, polyarylate resin (PA) contains repeating unit (1). Thus, the solubility of the polyarylate resin (PA) in the solvent for forming the photosensitive layer can be improved. Furthermore, when the ratio n ₁ / n ₂ of the number n ₁ of the repeating units (1) to the number n ₂ of the repeating units (2) is 1.0 or more, the polyarylate resin (PA ) Can be further improved. When the solubility of the polyarylate resin (PA) is improved, the photosensitive layer can be suitably formed, and the abrasion resistance of the photosensitive member can be improved.

  The polyarylate resin (PA) is, in addition to the repeating units (1), (2) and (3), a repeating unit represented by the chemical formula (4) (hereinafter sometimes referred to as repeating unit (4)) It is preferable to further include When the polyarylate resin (PA) contains the repeating unit (4), the abrasion resistance of the photoreceptor can be further improved.

Next, the general formula (1) will be described in detail. Examples of the alkyl group having 2 or 3 carbon atoms represented by R ⁴ in the general formula (1) include an ethyl group, an n-propyl group and an isopropyl group. The alkyl group having 2 or 3 carbon atoms is preferably an ethyl group or an isopropyl group.

The cycloalkylidene (cycloalkylidene) group of the general formula (1) R ³ and R ⁴ are 5 or 6 carbon atoms represented bonded to each other in include cyclopentylidene and cyclohexylidene groups. The cyclopentylidene group and the cyclohexylidene group are represented by the following chemical formulas (5) and (6), respectively. The cycloalkylidene group having 5 or 6 carbon atoms is preferably a cyclohexylidene group.

  Preferred examples of the repeating unit (1) include repeating units represented by the chemical formulas (1-1), (1-2), (1-3), (1-4) and (1-5). Be Hereinafter, the repeating units represented by the chemical formulas (1-1), (1-2), (1-3), (1-4) and (1-5) may be repeating units (1-1), respectively It may be described as (1-2), (1-3), (1-4) and (1-5).

  The polyarylate resin (PA) may contain only one kind of repeating unit (1). Or polyarylate resin (PA) may contain 2 or more types of repeating unit (1).

The ratio n ₁ / n ₂ of the number n ₁ of repeating units (1) contained in the polyarylate resin (PA) to the number n ₂ of repeating units (2) contained in the polyarylate resin (PA) is 1.0 It is above. That is, the number n ₁ of the repeating units (1) is equal to the number n ₂ of the repeating units (2) or more than the number n ₂ of the repeating units (2). When the ratio n ₁ / n ₂ is 1.0 or more, the solubility of the polyarylate resin (PA) in the solvent for forming the photosensitive layer can be improved, and the abrasion resistance of the photoreceptor can be improved. . In order to improve the abrasion resistance of the photosensitive member, the ratio n ₁ / n ₂ is preferably 10.0 or less, and more preferably 5.0 or less. In order to improve the abrasion resistance of the photoreceptor while improving the solubility of the polyarylate resin (PA) in the solvent for forming the photosensitive layer, the ratio n ₁ / n ₂ is 1.0, 2.0, It is also preferable that it is within the range of two values selected from 3.0, 5.0 and 10.0. The ratio n ₁ / n ₂ may be, for example, 1.0 or more and less than 2.0, or 2.0 or more and 5.0 or less. The ratio n ₁ / n ₂ may be, for example, 1.0 or 3.0.

When the polyarylate resin (PA) contains the repeating unit (4), the repeating unit (4) contained in the polyarylate resin (PA) relative to the number n ₃ of the repeating units (3) contained in the polyarylate resin (PA) The ratio n ₄ / n ₃ of the number n ₄ is preferably greater than 0.0, more preferably 0.1 or more, and still more preferably 0.5 or more. The ratio n ₄ / n ₃ is preferably 5.0 or less, more preferably 3.0 or less, and still more preferably 1.5 or less. The ratio n ₁ / n ₂ is also preferably in the range of two values selected from 0.1, 0.5, 1.0, 1.5, 3.0 and 5.0. The ratio n ₄ / n ₃ may be, for example, 1.0.

The ratio n ₁ / n ₂ can be adjusted by changing the amount of the compound (BP-1) and the amount of the compound (BP-2) added when producing the polycarbonate resin (PA). In addition, the ratio n ₄ / n ₃ may be adjusted by changing the amount of the compound (DC-3) and the amount of the compound (DC-4) added when producing the polycarbonate resin (PA). it can. In addition, a compound (BP-1), a compound (BP-2), a compound (DC-3) and a compound (DC-4) will be described later.

The ratio n ₁ / n ₂ and the ratio n ₄ / n ₃ are not values obtained from one molecular chain, respectively, but from the whole (multiple molecular chains) of the polyarylate resin (PA) contained in the photosensitive layer It is an average value of the obtained values. The ratio n ₁ / n ₂ and the ratio n ₄ / n ₃ were each obtained by measuring the ¹ H-NMR spectrum of the polyarylate resin (PA) using a proton nuclear magnetic resonance spectrometer, and the obtained ¹ H-NMR spectrum It can be calculated from

Specific examples of the polyarylate resin (PA) include the following polyarylate resins.
Polyarylate resin (polyarylate containing a repeating unit (1-1), (2) and (3), having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less, not including a repeating unit (4) Resin (I) may be described);
Polyarylate resin (polyarylate resin (II) containing repeating units (1-5), (2) and (3) and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less is there);
A polyarylate resin (polyarylate resin (III) containing a repeating unit (1-1), (2), (3) and (4) and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less May be mentioned);
Polyarylate resin (polyarylate resin (IV) containing repeating units (1-2), (2) and (3) and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less is there);
A polyarylate resin (polyarylate resin (V) containing repeating units (1-3), (2) and (3) and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less is there);
Polyarylate resin (polyarylate resin (VI) containing repeating units (1-4), (2) and (3) and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less And the repeating units (1-1), (2) and (3), and the repeating unit (4), wherein the ratio n ₁ / n ₂ is 1.0 or more and less than 2.0. Resin (sometimes described as polyarylate resin (VII)).

More specific examples of the polyarylate resin (PA) include the following polyarylate resins.
Polyarylate resin (polyarylate resin (i) containing only repeating units (1-1), (2) and (3) as a repeating unit and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less May be written as);
Polyarylate resin (polyarylate resin (ii) containing only repeating units (1-5), (2) and (3) as a repeating unit and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less May be written as);
Polyarylate resin (polyarylate containing only repeating units (1-1), (2), (3) and (4) as repeating units and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less Resin (iii) may be described);
Polyarylate resin (polyarylate resin (iv) containing only repeating units (1-2), (2) and (3) as a repeating unit and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less May be written as);
Polyarylate resin (polyarylate resin (v) containing only repeating units (1-3), (2) and (3) as a repeating unit and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less May be written as);
Polyarylate resin (polyarylate resin (vi) containing only repeating units (1-4), (2) and (3) as a repeating unit and having a ratio n ₁ / n ₂ of 2.0 or more and 5.0 or less And a repeating unit containing only repeating units (1-1), (2) and (3), and having a ratio n ₁ / n ₂ of 1.0 or more and less than 2.0. Alilate resin (sometimes described as polyarylate resin (vii)).

  More specific examples of the polyarylate resin (PA) include polyarylate resins represented by the chemical formulas (R-1) to (R-7) (hereinafter each of the polyarylate resins (R-1) to (R) -7) is mentioned. In the chemical formulas (R-1) to (R-7), the numeral attached at the lower right of each repeating unit is a percentage (%) of the number of each repeating unit to the total number of repeating units contained in the polyarylate resin ). The total number of repeating units is the sum of the number of repeating units derived from bisphenol and the number of repeating units derived from dicarboxylic acid. Further, for convenience of description, in each of the chemical formulas (R-1), (R-2) and (R-4) to (R-7), two repeating units (3) are described. However, the percentage of the number of repeating units (3) to the total number of repeating units contained in each of the polyarylate resins (R-1), (R-2) and (R-4) to (R-7) is 50.0% (the sum of the numbers attached to the lower right of the two repeating units (3)).

  In order to improve the abrasion resistance of the photosensitive member, a repeating unit (1-5) is preferable as the repeating unit (1). As polyarylate resin (PA) whose repeating unit (1) is repeating unit (1-5), polyarylate resin (II) is preferable, polyarylate resin (ii) is more preferable, and polyarylate resin (R-2) Is more preferred.

  In order to improve the abrasion resistance of the photosensitive member, the repeating unit (1-1) is also preferable as the repeating unit (1). As polyarylate resin (PA) whose repeating unit (1) is repeating unit (1-1), polyarylate resin (I) and (III) are preferable, and polyarylate resin (i) and (iii) are more preferable. And polyarylate resins (R-1) and (R-3) are more preferable.

  In order to further improve the abrasion resistance of the photosensitive member, it is preferable that the repeating unit (1) is the repeating unit (1-1), and the repeating unit (4) is further included. As polyarylate resin (PA) in which repeating unit (1) is repeating unit (1-1) and further contains repeating unit (4), polyarylate resin (III) is preferable, and polyarylate resin (iii) is more preferable. And polyarylate resins (R-3) are more preferable.

  In the polyarylate resin (PA), the bisphenol-derived repeating unit and the dicarboxylic acid-derived repeating unit are adjacently bonded to each other. The number of bisphenol-derived repeating units contained in the polyarylate resin (PA) is equal to the number of dicarboxylic acid-derived repeating units. The bisphenol-derived repeating units are, for example, repeating units (1) and (2). The dicarboxylic acid-derived repeating unit is, for example, repeating unit (3). When the polyarylate resin (PA) contains the repeating unit (4), the dicarboxylic acid-derived repeating unit is, for example, repeating units (3) and (4).

  The polyarylate resin (PA) may be, for example, a random copolymer, an alternating copolymer, a periodic copolymer or a block copolymer. In the polyarylate resin (PA), the arrangement of the repeating units is not particularly limited as long as the bisphenol-derived repeating unit and the dicarboxylic acid-derived repeating unit are adjacently bonded to each other. For example, the repeating unit (1) may be bonded to both ends of the repeating unit (3). Alternatively, the repeating unit (2) may be bonded to both ends of the repeating unit (3). Alternatively, the repeating unit (1) may be bonded to one end of the repeating unit (3), and the repeating unit (2) may be bonded to the other end of the repeating unit (3).

  When polyarylate resin (PA) does not contain repeating unit (4), polyarylate resin (PA) may contain only repeating units (1), (2) and (3) as a repeating unit. When the polyarylate resin (PA) does not contain the repeating unit (4), the polyarylate resin (PA) is added to the repeating units (1), (2) and (3) as a repeating unit to obtain a repeating unit (1) The repeating units other than (2), (3) and (4) may be further included.

  When the polyarylate resin (PA) contains the repeating unit (4), the polyarylate resin (PA) contains only the repeating units (1), (2), (3) and (4) as the repeating unit. It is also good. When the polyarylate resin (PA) contains the repeating unit (4), the polyarylate resin (PA) is added to the repeating units (1), (2), (3) and (4) as a repeating unit, and is repeated. It may further contain repeating units other than units (1), (2), (3) and (4).

  The viscosity average molecular weight of the polyarylate resin (PA) is preferably 10,000 or more, more preferably 20,000 or more, still more preferably 30,000 or more, and 40,000 or more. Is particularly preferred. When the viscosity average molecular weight of the polyarylate resin (PA) is 10,000 or more, the abrasion resistance of the photoreceptor can be improved. On the other hand, the viscosity average molecular weight of the binder resin is preferably 80,000 or less, and more preferably 70,000 or less. When the viscosity average molecular weight of the binder resin is 80,000 or less, the polyarylate resin (PA) is easily dissolved in the solvent for forming the charge transport layer and the solvent for forming the single layer type photosensitive layer.

  The method for producing the polyarylate resin (PA) is not particularly limited. Examples of the method for producing the polyarylate resin (PA) include a method of condensation-polymerizing bisphenol for forming a bisphenol-derived repeating unit and dicarboxylic acid for forming a dicarboxylic acid-derived repeating unit. For condensation polymerization, known synthesis methods (for example, solution polymerization, melt polymerization or interfacial polymerization) can be employed.

As a bisphenol for constituting a bisphenol repeating unit, for example, a compound represented by a general formula (BP-1) (hereinafter sometimes referred to as a compound (BP-1)), and a chemical formula (BP-2) And a compound represented by (which may hereinafter be described as a compound (BP-2)). As a dicarboxylic acid for comprising a dicarboxylic acid repeating unit, the compound (Hereinafter, it may describe as a compound (DC-3).) Represented by Chemical formula (DC-3) is mentioned. When the polyarylate resin (PA) contains the repeating unit (4), a compound represented by a chemical formula (DC-4) (hereinafter referred to as a compound (DC-) in addition to the compound (DC-3) as a dicarboxylic acid 4) may be further added). R ¹ in the general formula ^{(BP-1), R 2} , R 3 and R ⁴ are each the same meaning as in formula ^{(1) R 1, R 2} , R 3 and R ⁴ in.

  Preferable examples of the compound (BP-1) include compounds represented by chemical formulas (BP-1-1) to (BP-1-5) (hereinafter, each of compounds (BP-1-1) to (BP) 1) may be described as 1) -5).

  Bisphenols (for example, compound (BP-1) and compound (BP-2)) may be derivatized to aromatic diacetate and used. The dicarboxylic acids (e.g., compound (DC-3) and compound (DC-4)) may be derivatized and used. Examples of derivatives of dicarboxylic acid include dicarboxylic acid dichloride, dicarboxylic acid dimethyl ester, dicarboxylic acid diethyl ester and dicarboxylic acid anhydride. The dicarboxylic acid dichloride is a compound in which two “—C (= O) —OH” groups possessed by the dicarboxylic acid are each replaced by a “—C (= O) —Cl” group.

  In condensation polymerization of bisphenol and dicarboxylic acid, one or both of a base and a catalyst may be added. Examples of bases include sodium hydroxide. Examples of catalysts include benzyltributyl ammonium chloride, ammonium chloride, ammonium bromide, quaternary ammonium salts, triethylamine and trimethylamine. The polyarylate resin (PA) according to the present embodiment has been described above.

<Photoreceptor>
Next, a photoreceptor provided with a photosensitive layer containing the polyarylate resin (PA) of the present embodiment will be described. The photoreceptor comprises a conductive substrate and a photosensitive layer. The photosensitive layer contains a charge generating agent, a hole transporting agent, and a binder resin. The photoreceptor may be a laminate type electrophotographic photoreceptor (hereinafter sometimes referred to as a laminate type photoreceptor), and a single layer type electrophotographic photoreceptor (hereinafter referred to as a single layer type photoreceptor) Yes).

(Laminated photoreceptor)
Hereinafter, with reference to FIG. 1A to FIG. 1C, the photosensitive member 1 in the case of a laminated type photosensitive member will be described. FIGS. 1A to 1C are partial cross-sectional views showing an example of the photosensitive member 1 (laminated photosensitive member).

  As shown in FIG. 1A, a laminated photosensitive member as the photosensitive member 1 includes, for example, a conductive substrate 2 and a photosensitive layer 3. Photosensitive layer 3 includes charge generation layer 3a and charge transport layer 3b. That is, in the multi-layered photosensitive member, the charge generation layer 3 a and the charge transport layer 3 b are provided as the photosensitive layer 3.

  In order to improve the abrasion resistance of the multi-layer type photosensitive member, as shown in FIG. 1A, the charge generation layer 3a is provided on the conductive substrate 2, and the charge transport layer 3b is formed on the charge generation layer 3a. It is preferable to be provided. However, as shown in FIG. 1B, in the multi-layer type photosensitive member as the photosensitive member 1, the charge transport layer 3b is provided on the conductive substrate 2, and the charge generation layer 3a is provided on the charge transport layer 3b. May be

  As shown in FIG. 1C, the multi-layered photosensitive member as the photosensitive member 1 may be provided with a conductive substrate 2, a photosensitive layer 3 and an intermediate layer 4 (undercoating layer). The intermediate layer 4 is provided between the conductive substrate 2 and the photosensitive layer 3. As shown in FIGS. 1 (a) and 1 (b), the photosensitive layer 3 may be provided directly on the conductive substrate 2. Alternatively, as shown in FIG. 1C, the photosensitive layer 3 may be provided on the conductive substrate 2 via the intermediate layer 4. A protective layer 5 (see FIG. 2C) may be provided on the photosensitive layer 3. Alternatively, the protective layer 5 may not be provided on the photosensitive layer 3. For example, the charge transport layer 3 b may be provided as the outermost surface layer of the photosensitive member 1.

  The thickness of the charge generation layer 3a is not particularly limited, but is preferably 0.01 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 3 μm or less. The thickness of the charge transport layer 3b is not particularly limited, but is preferably 2 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less. In the above, with reference to FIG. 1A to FIG. 1C, the photosensitive member 1 in the case of the laminated type photosensitive member has been described.

(Single-layer type photoreceptor)
Hereinafter, with reference to FIGS. 2A to 2C, the photoreceptor 1 in the case of a single-layer photoreceptor will be described. FIGS. 2A to 2C are partial cross-sectional views showing another example of the photosensitive member 1 (single-layer type photosensitive member).

  As shown in FIG. 2A, a single-layer type photosensitive member as the photosensitive member 1 includes, for example, a conductive substrate 2 and a photosensitive layer 3. The single-layer type photosensitive member as the photosensitive member 1 is provided with a single-layer photosensitive layer 3 (hereinafter, sometimes referred to as a single-layer type photosensitive layer 3c).

  As shown in FIG. 2B, the single-layer type photosensitive member as the photosensitive member 1 may be provided with a conductive substrate 2, a single-layer type photosensitive layer 3c, and an intermediate layer 4 (undercoating layer). . The intermediate layer 4 is provided between the conductive substrate 2 and the single-layer photosensitive layer 3c. As shown in FIG. 2A, the photosensitive layer 3 may be provided directly on the conductive substrate 2. Alternatively, as shown in FIG. 2 (b), the photosensitive layer 3 may be provided on the conductive substrate 2 via the intermediate layer 4.

  As shown in FIG. 2C, the single-layer type photosensitive member as the photosensitive member 1 may include the conductive substrate 2, the single-layer type photosensitive layer 3 c, and the protective layer 5. The protective layer 5 is provided on the single layer type photosensitive layer 3c. Alternatively, the protective layer 5 may not be provided on the single-layer type photosensitive layer 3c. For example, the single-layer type photosensitive layer 3 c may be provided as the outermost surface layer of the photosensitive member 1.

  The thickness of the single layer type photosensitive layer 3c is not particularly limited, but is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less. In the above, with reference to FIGS. 2A to 2C, the photosensitive member 1 in the case of the single-layer type photosensitive member has been described. The photoreceptor will be described in more detail below.

<Photosensitive layer>
When the photosensitive member is a laminated type photosensitive member, the charge generating layer of the photosensitive layer contains a charge generating agent. The charge generation layer may contain a binder resin for charge generation layer (hereinafter sometimes referred to as a base resin). The charge generation layer may optionally contain an additive. The charge transport layer of the photosensitive layer contains a hole transport agent and a binder resin. The charge transport layer may contain an additive, if necessary.

  When the photoreceptor is a single layer photoreceptor, the single layer photosensitive layer as the photosensitive layer contains a charge generating agent, a hole transfer agent, and a binder resin. The single layer type photosensitive layer may further contain an electron transfer agent. The single layer type photosensitive layer may contain an additive, if necessary.

(Binder resin)
The binder resin contains the polyarylate resin (PA) of the present embodiment. The photosensitive layer (for example, a charge transport layer or a single layer photosensitive layer) contains polyarylate resin (PA) as a binder resin. When the photosensitive layer contains a polyarylate resin (PA), as described above, the abrasion resistance of the photosensitive member can be improved.

  The photosensitive layer may contain only one kind of polyarylate resin (PA) as a binder resin. In addition, the photosensitive layer may contain two or more of polyarylate resin (PA) as a binder resin.

  The photosensitive layer may contain only polyarylate resin (PA) as a binder resin. In addition to the polyarylate resin (PA), the photosensitive layer may further contain a binder resin other than the polyarylate resin (PA) (hereinafter sometimes referred to as another binder resin) as a binder resin. Good. The content of the polyarylate resin (PA) is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, with respect to the mass of the binder resin.

  As other binder resin, a thermoplastic resin, a thermosetting resin, and a photocurable resin are mentioned, for example. As a thermoplastic resin, for example, polycarbonate resin, polyarylate resin other than polyarylate resin (PA), styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic acid polymer, Styrene-acrylic acid copolymer, polyethylene resin, ethylene-vinyl acetate copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide resin, Urethane resin, polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyester resin, polyvinyl acetal resin and polyether resin are mentioned. As a thermosetting resin, a silicone resin, an epoxy resin, a phenol resin, a urea resin, and a melamine resin are mentioned, for example. Examples of the photocurable resin include acrylic acid adducts of epoxy compounds and acrylic acid adducts of urethane compounds. The photosensitive layer may contain only one of these other binder resins, or may contain two or more.

(Base resin)
When the photoreceptor is a laminated photoreceptor, the charge generation layer contains a base resin. Examples of base resins are the same as the examples of the other binder resins described above. The charge generation layer may contain only one type of base resin, or may contain two or more types. In order to form the charge generation layer and the charge transport layer well, the base resin contained in the charge generation layer is preferably different from the binder resin contained in the charge transport layer.

(Hole transport agent)
Examples of the hole transport agent include triphenylamine derivatives, diamine derivatives (eg, N, N, N ′, N′-tetraphenylbenzidine derivatives, N, N, N ′, N′-tetraphenylphenylenediamine derivatives, N, N, N ', N'-tetraphenyl naphthyl didiamine derivative, N, N, N', N'-tetraphenyl phenanthrylene diamine derivative or di (aminophenyl ethenyl) benzene derivative), oxadiazole type A compound (for example, 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole), a styryl compound (for example, 9- (4-diethylaminostyryl) anthracene), a carbazole compound (for example, , Polyvinylcarbazole), organic polysilane compounds, pyrazoline compounds (eg, 1-phenyl-3- (p-) Methylamino phenyl) pyrazoline), hydrazone compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds and triazole compounds.

  The hole transfer agent preferably contains a compound represented by the general formula (10), (11), (12), (13) or (14). Hereinafter, the compounds represented by the general formulas (10), (11), (12), (13) and (14) will be described respectively as compounds (10), (11), (12), (13) and It may be described as 14). The photosensitive layer (for example, charge transport layer or single-layer photosensitive layer) preferably contains the compound (10), (11), (12), (13) or (14) as a hole transport agent. . By containing the compound (10), (11), (12), (13) or (14) as a hole transfer agent in the photosensitive layer, it is possible to improve the abrasion resistance of the photosensitive member and to improve the sensitivity of the photosensitive member. Characteristics can be improved.

  The compound (10) is represented by the following general formula (10).

In the general formula (10), each of R ¹⁰¹ , R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , R ¹⁰⁶ , R ¹⁰⁷ and R ¹⁰⁸ independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, the number of carbon atoms This represents a phenyl group which may have an alkyl group of 1 or more and 8 or less, or an alkoxy group having 1 or more and 8 or less carbon atoms. Adjacent two of R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , R ¹⁰⁶ and R ¹⁰⁷ may combine to represent a cycloalkane having 5 to 7 carbon atoms. Each of R ¹⁰² and R ¹⁰⁹ independently represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms. Each of b ₁ and b ₂ independently represents an integer of 0 or more and 5 or less.

The alkyl group having 1 to 8 carbon atoms represented by R ^{101 to} R ¹⁰⁹ in the general formula (10) is preferably an alkyl group having 1 to 6 carbon atoms, and is an alkyl group having 1 to 4 carbon atoms. Is more preferred, and methyl or n-butyl is more preferred.

In the general formula (10), a phenyl group represented by R ¹⁰¹ to R ¹⁰⁹ may have 1 to 8 alkyl group carbon atoms. As a C1-C8 alkyl group which a phenyl group has, a C1-C6 alkyl group is preferable, a C1-C4 alkyl group is more preferable, and a methyl group is still more preferable.

In the general formula (10), the alkoxy group R ¹⁰¹ to R ¹⁰⁹ carbon atoms 1 to 8 represent preferably an alkoxy group having 1 to 4 carbon atoms, a methoxy group or an ethoxy group is more preferable.

In the general formula (10), adjacent two of R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , R ¹⁰⁶ and R ¹⁰⁷ may be bonded to each other to represent a cycloalkane having 5 to 7 carbon atoms. For example, R ¹⁰⁶ and R ¹⁰⁷ adjacent one of ^{R 103, R 104, R 105} , R 106 and R ¹⁰⁷ may be bonded to each other to form a 5 carbon atoms to 7 cycloalkane. When two adjacent ^ones of R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , R ¹⁰⁶ and R ¹⁰⁷ are bonded to each other to form a cycloalkane having 5 to 7 carbon atoms, the cycloalkane having 5 to 7 carbon atoms is The alkane is condensed with a phenyl group to which R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , R ¹⁰⁶ and R ¹⁰⁷ are bonded to form a bicyclic fused ring group. In this case, the condensation site of a cycloalkane having 5 to 7 carbon atoms and a phenyl group may contain a double bond. As a cycloalkane having 5 to 7 carbon atoms, which is represented by two adjacent ^ones of R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , R ¹⁰⁶ and R ¹⁰⁷ being bonded to each other, cyclohexane is preferable.

If b ₁ represents an integer of 2 to 5, a plurality of R ¹⁰² may be the same or different from each other. If b ₂ represents an integer of 2 to 5, a plurality of R ¹⁰⁹ independently represent may be the same or different from each other. Each of b ₁ and b ₂ preferably independently represents 0 or 1.

In the general formula (10), R ¹⁰¹ and R ¹⁰⁸ preferably represent a phenyl group having a C 1 to C 8 alkyl group or a hydrogen atom. R ¹⁰² and R ¹⁰⁹ preferably represent an alkyl group having 1 to 8 carbon atoms. Each of R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , R ¹⁰⁶ and R ¹⁰⁷ preferably independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. . Alternatively, it is preferable that adjacent two of R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , R ¹⁰⁶ and R ¹⁰⁷ be bonded to each other to form a cycloalkane having 5 to 7 carbon atoms. Each of b ₁ and b ₂ preferably independently represents 0 or 1.

  Preferred examples of the compound (10) include compounds represented by chemical formulas (HTM-1), (HTM-2), (HTM-3) and (HTM-4). The compounds represented by the chemical formulas (HTM-1), (HTM-2), (HTM-3) and (HTM-4) are referred to as compounds (HTM-1), (HTM-2), (HTM) respectively below. -3) and (HTM-4) may be described.

  The compound (11) is represented by the following general formula (11).

In formula (11), R ¹¹¹ and R ¹¹² each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group. Each of R ¹¹³ , R ¹¹⁴ , R ¹¹⁵ , R ¹¹⁶ , R ¹¹⁷ and R ¹¹⁸ independently represents an alkyl group having 1 to 8 carbon atoms or a phenyl group. Each of d ₁ and d ₂ independently represents 0 or 1. d ₃ , d ₄ , d ₅ and d ₆ each independently represent an integer of 0 or more and 5 or less. d ₇ and d ₈ each independently represent an integer of 0 or more and 4 or less.

In the general formula (11), the alkyl group having 1 to 8 carbon atoms represented by R ^{111 to} R ¹¹⁸ is preferably an alkyl group having 1 to 4 carbon atoms, and is a methyl group or an ethyl group Is more preferred.

In the general formula (11), when d ₃ represents an integer of 2 or more and 5 or less, the plurality of R ¹¹³ may be the same or different. When d ₄ represents an integer of 2 or more and 5 or less, the plurality of R ¹¹⁴ may be the same as or different from each other. When d ₅ represents an integer of 2 to 5, a plurality of R ¹¹⁵ may be the same or different from each other. When d ₆ represents an integer of 2 or more and 5 or less, the plurality of R ¹¹⁶ may be the same as or different from each other. When d ₇ represents an integer of 2 or more and 4 or less, the plurality of R ¹¹⁷ may be the same as or different from each other. When d ₈ represents an integer of 2 or more and 4 or less, the plurality of R ¹¹⁸ may be the same as or different from each other.

  Preferred examples of the compound (11) include compounds represented by chemical formulas (HTM-5), (HTM-6) and (HTM-7). Hereinafter, compounds represented by chemical formulas (HTM-5), (HTM-6) and (HTM-7) will be described as compounds (HTM-5), (HTM-6) and (HTM-7), respectively. Sometimes.

  The compound (12) is represented by the following general formula (12).

In the general formula (12), each of R ¹²¹ , R ¹²² , R ¹²³ , R ¹²⁴ , R ¹²⁵ and R ¹²⁶ independently represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or 1 to 8 carbon atoms. The following alkoxy groups are represented. Each of e ₁ , e ₂ , e ₄ and e ₅ independently represents an integer of 0 or more and 5 or less. Each of e ₃ and e ₆ independently represents an integer of 0 or more and 4 or less.

The alkyl group having 1 to 8 carbon atoms represented by R ^{121 to} R ¹²⁶ in the general formula (12) is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.

With respect to the diphenylaminophenylethenyl group having R ¹²¹ , R ¹²² and R ¹²³ , the diphenylaminophenyl ethenyl group having R ¹²⁴ , R ¹²⁵ and R ¹²⁶ can be positioned at any of the ortho position, meta position and para position It may be done. The diphenylaminophenylethenyl group having R ¹²⁴ , R ¹²⁵ and R ¹²⁶ is preferably located at the ortho position or para position with respect to the diphenylaminophenyl ethenyl group having R ¹²¹ , R ¹²² and R ¹²³ .

When e ₁ represents an integer of 2 or more and 5 or less in the general formula (12), the plurality of R ¹²¹ may be the same as or different from each other. When e ₂ represents an integer of 2 or more and 5 or less, the plurality of R ¹²² may be the same as or different from each other. When e ₃ represents an integer of 2 or more and 4 or less, the plurality of R ¹²³ may be the same as or different from each other. When e ₄ represents an integer of 2 or more and 5 or less, the plurality of R ¹²⁴ may be the same as or different from each other. When e ₅ represents an integer of 2 or more and 5 or less, plural R ^{125 s} may be the same as or different from each other. When e ₆ represents an integer of 2 or more and 4 or less, the plurality of R ¹²⁶ may be the same as or different from each other.

In the general formula (12), it is preferable that e ₁ , e ₂ , e ₄ and e ₅ each independently represent an integer of 0 or more and 2 or less. One of e ₁ and e ₂ represents 0 and the other represents 2 and one of e ₄ and e ₅ represents 0 and the other represents 2 or e ₁ , e ₂ , e ₄ and e ₅ each is 1 It is more preferable to represent Each of e ₃ and e ₆ preferably represents 0.

In the general formula (12), R ¹²¹ , R ¹²² , R ¹²³ , R ¹²⁴ , R ¹²⁵ and R ¹²⁶ each preferably independently represent an alkyl group having 1 to 8 carbon atoms. Preferably, e ₁ , e ₂ , e ₄ and e ₅ each independently represent an integer of 0 or more and 2 or less. Each of e ₃ and e ₆ preferably represents 0.

  Preferred examples of the compound (12) include compounds represented by chemical formulas (HTM-8) and (HTM-9). Hereinafter, the compounds represented by the chemical formulas (HTM-8) and (HTM-9) may be described as compounds (HTM-8) and (HTM-9), respectively.

  The compound (13) is represented by the following general formula (13).

In the general formula (13), R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ³⁷ , R ³⁸ , R ³⁹ and R ^3A each independently represent a hydrogen atom or a methyl group.

  Preferred examples of the compound (13) include compounds represented by chemical formula (HTM-10). Hereinafter, the compound represented by a chemical formula (HTM-10) may be described as a compound (HTM-10).

  The compound (14) is represented by the following general formula (14).

In general formula (14), R ⁴¹ and R ⁴² each independently represent a hydrogen atom, a methyl group or an ethyl group, and the number of carbon atoms of the group represented by R ⁴¹ and the number of carbon atoms of the group represented by R ⁴² The sum of is two. R ⁴³ and R ⁴⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group, and the sum of the number of carbon atoms of the group represented by R ⁴³ and the number of carbon atoms of the group represented by R ⁴⁴ is 2.

  Preferred examples of the compound (14) include compounds represented by chemical formula (HTM-11). Hereinafter, the compound represented by a chemical formula (HTM-11) may be described as a compound (HTM-11).

  In order to improve the abrasion resistance of the photosensitive member, the compound (10), (11), (12), (13) or (14) is preferable as the hole transport agent. Among the compounds (10) to (14), the compound (10) or (11) is preferred as the hole transfer agent, in order to improve the sensitivity characteristics in addition to the abrasion resistance of the photoreceptor, the compound ( 11) is more preferable.

  Among the compounds (HTM-1) to (HTM-11), the compounds (HTM-1), (HTM-2), (HTM-1), HTM-3), (HTM-4), (HTM-5), (HTM-6), (HTM-9), (HTM-10) or (HTM-11) are preferred, and (HTM-3), (HTM-3) HTM-6), (HTM-9), (HTM-10) or (HTM-11) is more preferred. In order to improve the sensitivity characteristics in addition to the abrasion resistance of the photosensitive member, among the compounds (HTM-1) to (HTM-11), the compounds (HTM-1) and (HTM-) may be used as the hole transport agent. 2), (HTM-4) or (HTM-6) is preferable, and the compound (HTM-6) is more preferable.

  The photosensitive layer may contain only one of the compounds (10), (11), (12), (13) and (14) as a hole transport agent. Alternatively, the photosensitive layer may contain two or more of the compounds (10), (11), (12), (13) and (14) as a hole transport agent. The photosensitive layer may contain only one kind of compounds (HTM-1) to (HTM-11) as a hole transport agent. Alternatively, the photosensitive layer may contain two or more of the compounds (HTM-1) to (HTM-11) as a hole transport agent.

  The photosensitive layer may contain only the compound (10), (11), (12), (13) or (14) as a hole transport agent. Alternatively, the photosensitive layer may be a compound other than (10), (11), (12), (13) and (14) in addition to the compounds (10), (11), (12), (13) or (14). May further contain a hole transport agent of The content of the compound (10), (11), (12), (13) or (14) is preferably 80% by mass or more and 90% by mass or more based on the mass of the hole transfer agent. And more preferably 100% by mass.

  The photosensitive layer may contain only the compounds (HTM-1) to (HTM-11) as a hole transport agent. Alternatively, the photosensitive layer may further contain a hole transfer agent other than the compounds (HTM-1) to (HTM-11) in addition to the compounds (HTM-1) to (HTM-11). The content of the compounds (HTM-1) to (HTM-11) is preferably 80% by mass or more, more preferably 90% by mass or more, based on the mass of the hole transfer agent, and 100% by mass. % Is particularly preferred.

  When the photoreceptor is a laminate type photoreceptor, the content of the hole transport agent is preferably 10 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the binder resin contained in the charge transport layer. More preferably, it is 20 parts by mass or more and 100 parts by mass or less.

  When the photoreceptor is a single layer photoreceptor, the content of the hole transfer agent is 10 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the binder resin contained in the single layer photosensitive layer. Is preferable, and 10 parts by mass or more and 100 parts by mass or less are more preferable.

(Charge generating agent)
Examples of charge generating agents include phthalocyanine pigments, perylene pigments, bisazo pigments, trisazo pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squalene pigments, indigo pigments, azulenium pigments, cyanines Pigment, powder of inorganic photoconductive material (eg, selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide or amorphous silicon), pyrylium pigment, ansanthrone pigment, triphenylmethane pigment, selenium pigment, toluidine pigment, And pyrazoline pigments and quinacridone pigments. The photosensitive layer (charge generating layer or single-layer type photosensitive layer) may contain only one type of charge generating agent, or may contain two or more types.

  Examples of phthalocyanine pigments include metal-free phthalocyanines and metal phthalocyanines. Examples of metal phthalocyanines include titanyl phthalocyanine, hydroxygallium phthalocyanine and chlorogallium phthalocyanine. The metal-free phthalocyanine is represented by a chemical formula (CGM-1). The titanyl phthalocyanine is represented by a chemical formula (CGM-2).

  The phthalocyanine pigment may be crystalline or non-crystalline. Examples of crystals of metal-free phthalocyanine include, for example, X-type crystals of metal-free phthalocyanine (hereinafter sometimes referred to as X-type metal-free phthalocyanine). Examples of crystals of titanyl phthalocyanine include Y-type crystals of titanyl phthalocyanine (hereinafter sometimes referred to as Y-type titanyl phthalocyanine). Other examples of titanyl phthalocyanine crystals include α-type crystals and β-type crystals of titanyl phthalocyanine.

  For example, in a digital optical image forming apparatus (for example, a laser beam printer or a facsimile using a light source such as a semiconductor laser), it is preferable to use a photosensitive member having sensitivity in a wavelength region of 700 nm or more. As a charge generating agent, phthalocyanine pigments are preferable, metal-free phthalocyanines or titanyl phthalocyanines are more preferable, and X-type metal-free phthalocyanines or Y-type titanyl phthalocyanines are more preferable because they have high quantum yield in a wavelength region of 700 nm or more. , Y-type titanyl phthalocyanine is particularly preferred.

  For a photosensitive member applied to an image forming apparatus using a short wavelength laser light source (for example, a laser light source having a wavelength of 350 nm to 550 nm), an anthanthrone pigment is suitably used as a charge generating agent.

  When the photoreceptor is a laminated photoreceptor, the content of the charge generating agent is preferably 0.01 parts by mass or more and 10 parts by mass or less with respect to 1 part by mass of the base resin contained in the charge generation layer. The content is more preferably 0.5 parts by mass or more and 5 parts by mass or less and particularly preferably 0.5 parts by mass or more and 3 parts by mass or less.

  When the photoreceptor is a single layer photoreceptor, the content of the charge generating agent is 0.1 parts by mass to 50 parts by mass with respect to 100 parts by mass of the binder resin contained in the single layer photosensitive layer. It is preferable that it is 0.5 to 30 mass parts, It is especially preferable that it is 0.5 to 5 mass parts.

(Additive)
As the additive, for example, an electron acceptor, an antidegradant (for example, an antioxidant, a radical scavenger, a singlet quencher or an ultraviolet absorber), a softener, a surface modifier, an extender, a thickener, Dispersion stabilizers, waxes, donors, surfactants, plasticizers, sensitizers and leveling agents are included. Antioxidants include, for example, hindered phenols (eg, di (tert-butyl) p-cresol), hindered amines, paraphenylenediamines, arylalkanes, hydroquinones, spirochromans, spiroindanones and derivatives thereof. Antioxidants also include, for example, organic sulfur compounds and organic phosphorus compounds. As a leveling agent, dimethyl silicone oil is mentioned, for example. As a sensitizer, metaterphenyl is mentioned, for example.

(Combination of materials)
In order to further improve the abrasion resistance of the photoreceptor, the hole transport agent and the binder resin are preferably any of the combinations shown below. In addition, it is preferable that the hole transfer agent and the binder resin be any of the combinations shown below, and the charge generating agent be a Y-type titanyl phthalocyanine.

The binder resin is polyarylate resin (I) and the hole transport agent is any of compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (II) and the hole transport agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (III) and the hole transfer agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (IV) and the hole transport agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (V) and the hole transfer agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is polyarylate resin (VI) and the hole transfer agent is any of compounds (HTM-1) to (HTM-11); or the binder resin is polyarylate resin (VII), positive The hole transporting agent is any of compounds (HTM-1) to (HTM-11).

  In order to further improve the abrasion resistance of the photoreceptor, the hole transport agent and the binder resin are more preferably any of the combinations shown below. Further, it is more preferable that the hole transfer agent and the binder resin be any of the combinations shown below, and the charge generating agent be a Y-type titanyl phthalocyanine.

The binder resin is a polyarylate resin (i) and the hole transport agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (ii) and the hole transport agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (iii) and the hole transport agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (iv) and the hole transport agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (v) and the hole transfer agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is polyarylate resin (vi) and the hole transfer agent is any of compounds (HTM-1) to (HTM-11); or the binder resin is polyarylate resin (vii), positive The hole transporting agent is any of compounds (HTM-1) to (HTM-11).

  In order to further improve the abrasion resistance of the photoreceptor, it is more preferable that the hole transport agent and the binder resin be any of the combinations shown below. Further, it is more preferable that the hole transfer agent and the binder resin be any of the combinations shown below, and the charge generating agent be a Y-type titanyl phthalocyanine.

The binder resin is a polyarylate resin (R-1) and the hole transfer agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (R-2) and the hole transfer agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (R-3) and the hole transfer agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (R-4) and the hole transfer agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (R-5) and the hole transfer agent is any of the compounds (HTM-1) to (HTM-11);
The binder resin is a polyarylate resin (R-6) and the hole transfer agent is any of the compounds (HTM-1) to (HTM-11); or the binder resin is a polyarylate resin (R-7) And the hole transport agent is any of the compounds (HTM-1) to (HTM-11).

<Conductive substrate>
The conductive substrate is not particularly limited as long as it can be used as the conductive substrate of the photoreceptor. The conductive substrate may be made of a material at least the surface of which has conductivity. One example of the conductive substrate is a conductive substrate composed of a material having conductivity. Another example of the conductive substrate is a conductive substrate coated with a material having conductivity. As the material having conductivity, for example, aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel and brass can be mentioned. These materials having conductivity may be used alone, or two or more may be used in combination (for example, as an alloy). Among these materials having conductivity, aluminum and an aluminum alloy are preferable because charge transfer from the photosensitive layer to the conductive substrate is good.

  The shape of the conductive substrate is appropriately selected in accordance with the structure of the image forming apparatus. Examples of the shape of the conductive substrate include a sheet and a drum. In addition, the thickness of the conductive substrate is appropriately selected according to the shape of the conductive substrate.

<Middle class>
The intermediate layer (undercoat layer) contains, for example, inorganic particles and a resin (intermediate layer resin) used for the intermediate layer. Due to the presence of the intermediate layer, the flow of current generated when the photosensitive member is exposed can be smoothed and an increase in resistance can be suppressed while maintaining the insulation state to a degree that can suppress the occurrence of leakage.

  As the inorganic particles, for example, particles of metal (for example, aluminum, iron or copper), particles of metal oxide (for example, titanium oxide, alumina, zirconium oxide, tin oxide or zinc oxide) and nonmetal oxides (for example, silica) Particles of One of these inorganic particles may be used alone, or two or more thereof may be used in combination.

  Examples of the interlayer resin are the same as the examples of the other binder resins described above. In order to form the intermediate layer and the photosensitive layer well, the resin for the intermediate layer is preferably different from the binder resin contained in the photosensitive layer. The intermediate layer may contain an additive. Examples of the additive contained in the intermediate layer are the same as the examples of the additive contained in the photosensitive layer.

<Method of manufacturing photoreceptor>
As a method of manufacturing a photosensitive member, an example of a method of manufacturing a laminated type photosensitive member and an example of a method of manufacturing a single-layer type photosensitive member will be described.

(Method of manufacturing laminated type photoreceptor)
The method of manufacturing the multi-layer photosensitive member includes a photosensitive layer forming step. The photosensitive layer formation step includes a charge generation layer formation step and a charge transport layer formation step. In the charge generation layer formation step, first, a coating liquid for forming the charge generation layer (hereinafter, sometimes described as a coating liquid for charge generation layer) is prepared. A coating solution for charge generation layer is applied on a conductive substrate. Next, at least a part of the solvent contained in the applied coating solution for charge generation layer is removed to form a charge generation layer. The charge generation layer coating solution contains, for example, a charge generation agent, a base resin, and a solvent. Such a charge generating layer coating solution is prepared by dissolving or dispersing the charge generating agent and the base resin in a solvent. Additives may be added to the charge generation layer coating solution, if necessary.

  In the charge transport layer formation step, first, a coating solution for forming the charge transport layer (hereinafter, sometimes described as a coating solution for charge transport layer) is prepared. A charge transport layer coating solution is applied onto the charge generation layer. Next, at least a part of the solvent contained in the applied coating liquid for charge transport layer is removed to form a charge transport layer. The charge transport layer coating solution contains a hole transport agent, a binder resin, and a solvent. The charge transport layer coating solution can be prepared by dissolving or dispersing the hole transport agent and the binder resin in a solvent. Additives may be further added to the charge transport layer coating solution, if necessary.

(Method of manufacturing single layer type photoreceptor)
The method of manufacturing a single-layer type photosensitive member includes a single-layer type photosensitive layer forming step. In the single-layer type photosensitive layer forming step, a coating solution for forming a single-layer type photosensitive layer (hereinafter sometimes referred to as a coating solution for a single-layer type photosensitive layer) is prepared. A single-layer type photosensitive layer coating solution is applied onto a conductive substrate. Next, at least a part of the solvent contained in the applied coating solution for a single layer type photosensitive layer is removed to form a single layer type photosensitive layer. The coating solution for a single layer type photosensitive layer contains, for example, a charge generating agent, a hole transporting agent, a binder resin, and a solvent. The coating solution for a single layer type photosensitive layer is prepared by dissolving or dispersing the charge generating agent, the hole transporting agent, and the binder resin in a solvent. An electron transfer agent may be further added to the single-layer type photosensitive layer coating solution. If necessary, additives may be further added to the single-layer type photosensitive layer coating solution.

  The solvent contained in the coating solution for charge generation layer, the coating solution for charge transport layer, and the coating solution for single layer type photosensitive layer (hereinafter sometimes referred to as coating solution) dissolves each component contained in the coating solution. It is not particularly limited as long as it can be dispersed. As the solvent, for example, alcohol (more specifically, methanol, ethanol, isopropanol or butanol etc.), aliphatic hydrocarbon (more specifically, n-hexane, octane or cyclohexane etc.), aromatic hydrocarbon (more specifically, More specifically, benzene, toluene or xylene etc.), halogenated hydrocarbons (more specifically, dichloromethane, dichloroethane, carbon tetrachloride or chlorobenzene etc.), ethers (more specifically, dimethyl ether, diethyl ether, Tetrahydrofuran, propylene glycol monomethyl ether, ethylene glycol dimethyl ether or diethylene glycol dimethyl ether etc., ketones (more specifically, acetone, methyl ethyl ketone or cyclohexanone etc.), esters (more specifically, vinegar Ethyl or methyl acetate, etc.), dimethylformamide, dimethyl formamide, and dimethyl sulfoxide and the like. These solvents may be used alone or in combination of two or more.

  In the case of producing a multi-layered photoreceptor, the solvent contained in the charge transport layer coating solution is preferably different from the solvent contained in the charge generation layer coating solution. When the charge transport layer coating solution is applied onto the charge generation layer, it is preferable that the charge generation layer does not dissolve in the solvent of the charge transport layer coating solution.

  The coating solution is prepared by mixing the respective components and dispersing in a solvent. For mixing or dispersing, for example, a bead mill, roll mill, ball mill, attritor, paint shaker or ultrasonic disperser can be used.

  The coating liquid may contain, for example, a surfactant or a leveling agent, in order to improve the dispersibility of each component or the surface smoothness of each layer formed.

  The method for applying the coating solution is not particularly limited as long as the method can uniformly apply the coating solution. Examples of the coating method include dip coating, spray coating, spin coating and bar coating.

  The method for removing at least a part of the solvent contained in the coating liquid is not particularly limited as long as the solvent in the coating liquid can be evaporated. Examples of the method of removal include heating, reduced pressure, or a combination of heating and reduced pressure. More specifically, a method of heat treatment (hot air drying) using a high temperature dryer or a vacuum dryer is mentioned. The temperature of the heat treatment is, for example, 40 ° C. or more and 150 ° C. or less. The heat treatment time is, for example, 3 minutes or more and 120 minutes or less.

  The method of manufacturing the photosensitive member may further include the step of forming an intermediate layer, if necessary. A well-known method can be suitably selected for the process of forming an intermediate | middle layer.

  Hereinafter, the present invention will be more specifically described using examples. In addition, this invention is not limited at all to the range of an Example.

  The following hole transport agent and binder resin were prepared as materials for forming the charge transport layer of the layered photoreceptor.

(Hole transport agent)
Compounds (HTM-1) to (HTM-11) described in the embodiments were prepared as hole transport agents.

(Binder resin)
As binder resin, each of polyarylate resin (R-1)-(R-7) described by embodiment was synthesize | combined.

(Synthesis of polyarylate resin (R-1))
As a reaction vessel, a three-necked flask equipped with a thermometer, a three-way cock, and a dropping funnel was used. In a reaction vessel, compound (BP-1-1) (30.9 mmol), compound (BP-2) (10.3 mmol), p-tert-butylphenol (0.413 mmol) and sodium hydroxide (98 mmol) and benzyltributylammonium chloride (0.384 mmol) were introduced. The air in the reaction vessel was replaced with argon gas. Water (300 mL) was added to the contents of the reaction vessel. The contents of the reaction vessel were stirred at 50 ° C. for 1 hour. The contents of the reaction vessel were cooled until the temperature of the contents of the reaction vessel reached 10 ° C. to obtain an alkaline aqueous solution A.

  Next, the dicarboxylic acid dichloride (32.4 mmol) of compound (DC-3) was dissolved in chloroform (150 mL). Thus, a chloroform solution B was obtained.

  With respect to the alkaline aqueous solution A, using a dropping funnel, the chloroform solution B was slowly dropped over 110 minutes. While adjusting the temperature (liquid temperature) of the contents of the reaction vessel to 15 ± 5 ° C., the contents of the reaction vessel were stirred for 4 hours to allow the polymerization reaction to proceed. The upper layer (water layer) of the contents of the reaction vessel was removed using a decant to obtain an organic layer. Then, ion exchange water (400 mL) was added to the Erlenmeyer flask. The resulting organic layer was further added into an Erlenmeyer flask. Into an Erlenmeyer flask, chloroform (400 mL) and acetic acid (2 mL) were further added. The Erlenmeyer flask contents were stirred at room temperature (25 ° C.) for 30 minutes. The upper layer (water layer) of the Erlenmeyer flask contents was removed using a decant to obtain an organic layer. The obtained organic layer was washed with ion-exchanged water (1 L) using a separatory funnel. Washing with ion exchange water was repeated 5 times to obtain an organic layer washed with water. Next, the organic layer washed with water was filtered to obtain a filtrate. The obtained filtrate was slowly added dropwise to methanol (1 L) to obtain a precipitate. The precipitate was removed by filtration. The removed precipitate was vacuum dried at a temperature of 70 ° C. for 12 hours. Thereby, polyarylate resin (R-1) was obtained.

(Synthesis of polyarylate resin (R-2))
In the same manner as the synthesis of polyarylate resin (R-1), except that compound (BP-1-1) (30.9 mmol) was changed to compound (BP-1-5) (30.9 mmol), Polyarylate resin (R-2) was obtained.

(Synthesis of polyarylate resin (R-3))
The dicarboxylic acid dichloride (32.4 millimoles) of compound (DC-3), the dicarboxylic acid dichloride (16.2 millimoles) of compound (DC-3) and the dicarboxylic acid dichloride (16.2 millimoles) of compound (DC-4) Polyarylate resin (R-3) was obtained in the same manner as in the synthesis of polyarylate resin (R-1) except that it was changed to.

(Synthesis of polyarylate resin (R-4))
In the same manner as the synthesis of polyarylate resin (R-1), except that compound (BP-1-1) (30.9 mmol) was changed to compound (BP-1-2) (30.9 mmol), Polyarylate resin (R-4) was obtained.

(Synthesis of polyarylate resin (R-5))
In the same manner as the synthesis of polyarylate resin (R-1), except that compound (BP-1-1) (30.9 mmol) was changed to compound (BP-1-3) (30.9 mmol), Polyarylate resin (R-5) was obtained.

(Synthesis of polyarylate resin (R-6))
In the same manner as the synthesis of polyarylate resin (R-1), except that compound (BP-1-1) (30.9 mmol) was changed to compound (BP-1-4) (30.9 mmol), Polyarylate resin (R-6) was obtained.

(Synthesis of polyarylate resin (R-7))
Compound (BP-1-1) (30.9 millimoles) and Compound (BP-2) (10.3 millimoles), Compound (BP-1-1) (20.6 millimoles) and Compound (BP-2) A polyarylate resin (R-7) was obtained in the same manner as in the synthesis of the polyarylate resin (R-1) except that it was changed to (20.6 mmol).

  Viscosity averages of the obtained polyarylate resins (R-1), (R-2), (R-3), (R-4), (R-5), (R-6) and (R-7) The molecular weights were 50500, 51,000, 50,000, 45,000, 47, 300, 45, 500 and 48, 700 respectively.

The ¹ H-NMR spectrum of the obtained polyarylate resin (R-1) to (R-7) was measured using a proton nuclear magnetic resonance spectrometer (manufactured by JASCO Corporation, 300 MHz). CDCl ₃ was used as a solvent. Tetramethylsilane (TMS) was used as an internal standard sample. The chemical shift value of polyarylate resin (R-7) is shown below as a representative example of polyarylate resins (R-1) to (R-7). From the chemical shift value, it was confirmed that polyarylate resin (R-7) was obtained. It was confirmed that polyarylate resins (R-1) to (R-6) were obtained in the same manner as for the polyarylate resins (R-1) to (R-6).

Polyarylate resin (R-7): ¹ H-NMR (300 MHz, CDCl ₃ ) δ = 8.21-8.26 (m, 8H), 7.25-7.29 (m, 4H), 7.07 −7.23 (m, 20 H), 2.16 (q, 2 H), 1. 65 (s, 3 H), 0.78 (t, 3 H).

  Moreover, each of polyarylate resin (RA)-(RG) was also prepared as binder resin used by a comparative example. Each of the polyarylate resins (R-A) to (R-C) is represented by the following chemical formulas (R-A) to (R-C). In addition, the number attached | subjected to the lower right of each repeating unit shows the percentage (%) of the number of each repeating unit with respect to the total of the repeating unit contained in polyarylate resin.

  The polyarylate resin (R-D) used in the comparative example contains only the following repeating units (BP-A) and (BP-C) as bisphenol-derived repeating units. The polyarylate resin (R-D) contains only the following repeating units (3), (DC-T) and (DC-I) as dicarboxylic acid-derived repeating units. Percentage of number of repeating units (BP-A), percentage of number of repeating units (BP-C), percentage of number of repeating units (3) with respect to the total number of repeating units contained in polyarylate resin (R-D) , The percentage of the number of repeating units (DC-T), and the percentage of the number of repeating units (DC-I) are 25.0%, 25.0%, 25.0%, 15.0%, and It is 10.0%.

  The polyarylate resin (R-E) used in the comparative example contains only the following repeating unit (BP-C) as a bisphenol-derived repeating unit. Polyarylate resin (R-E) contains only the following repeating units (3), (DC-T), and (DC-I) as a dicarboxylic acid origin repeating unit. Percentage of number of repeating units (BP-C), percentage of number of repeating units (3), percentage of number of repeating units (DC-T) relative to the total number of repeating units contained in the polyarylate resin (R-E) And the percentage of the number of repeating units (DC-I) are 50.0%, 25.0%, 15.0%, and 10.0%, respectively.

  The polyarylate resin (RF) used in the comparative example contains only the following repeating unit (BP-A) as a bisphenol-derived repeating unit. The polyarylate resin (R-F) contains only the following repeating units (3), (DC-T) and (DC-I) as dicarboxylic acid-derived repeating units. Percentage of number of repeating units (BP-A), percentage of number of repeating units (3), percentage of number of repeating units (DC-T) relative to the total number of repeating units contained in the polyarylate resin (R-F) And the percentage of the number of repeating units (DC-I) are 50.0%, 25.0%, 15.0%, and 10.0%, respectively.

  The polyarylate resin (R-G) used in the comparative example contains only the following repeating unit (BP-Z) as a bisphenol-derived repeating unit. The polyarylate resin (R-G) contains only the following repeating units (3), (DC-T) and (DC-I) as dicarboxylic acid-derived repeating units. Percentage of number of repeating units (BP-Z), percentage of number of repeating units (3), percentage of number of repeating units (DC-T) relative to the total number of repeating units contained in the polyarylate resin (R-G) And the percentage of the number of repeating units (DC-I) are 50.0%, 25.0%, 15.0%, and 10.0%, respectively.

  In addition, viscosity average molecular weights of polyarylate resins (R-A), (R-B), (R-C), (R-D), (R-E), (R-F) and (R-G) Of 45, 300, 51,000, 46, 700, 46, 800, 51,000, 45,000 and 44, 400, respectively.

<Production of Multilayer Photosensitive Member>
Multilayer photoreceptors (A-1) to (A-16) and (B-1) to (B-7) were produced by the methods described below.

(Production of Multilayer Photosensitive Member (A-1))
First, an intermediate layer was formed. The surface-treated titanium oxide ("Prototype SMT-A" manufactured by Tayca Co., Ltd., number average primary particle diameter 10 nm) was prepared. In SMT-A, titanium oxide was surface-treated using alumina and silica, and surface-treated titanium oxide was further surface-treated using methyl hydrogen polysiloxane while wet-dispersing. Next, SMT-A (2 parts by mass), polyamide resin (quaternary copolyamide resin of "AMILAN (registered trademark) CM8000" manufactured by Toray Industries, Inc., polyamide 6, polyamide 12, polyamide 66 and polyamide 610) (1 part by mass) ), Methanol (10 parts by mass), butanol (1 parts by mass) and toluene (1 parts by mass) were charged into a vessel of a bead mill. The contents of the container were mixed for 5 hours using a bead mill to obtain an intermediate layer coating solution. The coating solution for an intermediate layer was filtered using a filter with an aperture of 5 μm. Then, using the dip coating method, the filtered coating solution for an intermediate layer was applied to the surface of the conductive substrate. As a conductive substrate, a drum-shaped support (diameter 30 mm, total length 246 mm) made of aluminum was used. Then, the applied coating solution for an intermediate layer was dried at 130 ° C. for 30 minutes to form an intermediate layer (film thickness 2 μm) on the conductive substrate.

  Next, a charge generation layer was formed. Specifically, Y-type titanyl phthalocyanine (1.5 parts by mass), polyvinyl acetal resin as a base resin ("S-LEC BX-5" manufactured by Sekisui Chemical Co., Ltd.) (1 parts by mass), propylene glycol monomethyl ether (40 parts by mass) ) And tetrahydrofuran (40 parts by mass) were placed in a vessel of a bead mill. The contents of the container were mixed for 2 hours using a bead mill to obtain a coating solution for charge generation layer. The coating solution for charge generation layer was filtered using a filter with an aperture of 3 μm. Then, using the dip coating method, the filtered coating solution for charge generation layer was applied onto the intermediate layer and dried at 50 ° C. for 5 minutes. Thus, a charge generation layer (film thickness 0.3 μm) was formed on the intermediate layer.

  Next, a charge transport layer was formed. Specifically, 50 parts by mass of a compound (HTM-1) as a hole transfer agent, 100 parts by mass of a polyarylate resin (R-1) as a binder resin, a hindered phenol antioxidant (manufactured by BASF, “IRGANOX (registered trademark) (Trademark) 1010 ′ ′), 2 parts by mass of tetrahydrofuran, 350 parts by mass of tetrahydrofuran, and 350 parts by mass of toluene were charged into a vessel of a ball mill. The contents of the container were mixed using a ball mill to obtain a charge transport layer coating solution. The charge transport layer coating solution was applied onto the charge generation layer by dip coating and dried at 120 ° C. for 40 minutes. Thereby, a charge transport layer (film thickness 20 μm) was formed on the charge generation layer. Thus, a laminate type photoreceptor (A-1) was obtained. In the laminate type photoreceptor (A-1), the intermediate layer was provided on the conductive substrate, the charge generation layer was provided on the intermediate layer, and the charge transport layer was provided on the charge generation layer.

(Production of Multilayer Photosensitive Substances (A-2) to (A-16) and (B-1) to (B-7))
In the same manner as in the production of the multilayer photosensitive member (A-1) except that the following points were changed, the multilayer photosensitive members (A-2) to (A-16) and (B-1) to (B-) were used. Each of 7) was manufactured. Although the compound (HTM-1) was used as a hole transfer agent in the production of the layered photosensitive member (A-1), the layered photosensitive members (A-2) to (A-16) and (B-1) were used. In the preparation of each of (B-7), a hole transport agent of the type shown in Tables 1 to 3 was used. Although the polyarylate resin (R-1) was used as a binder resin in the production of the laminate type photoreceptor (A-1), the laminate type photoreceptors (A-2) to (A-16) and (B-1) were used. In the preparation of each of (B-7), binder resins of the type shown in Tables 1 to 3 were used.

<Evaluation of charging characteristics>
With respect to each of the multi-layer photosensitive members (A-1) to (A-16) and (B-1) to (B-7), the charging characteristics are set under an environment of a temperature of 10.degree. C. and a relative humidity of 20% RH. evaluated. Specifically, using a drum sensitivity tester (manufactured by Gentec Co., Ltd.), the laminated photosensitive member was charged under the conditions of 31 rpm of the laminated photosensitive member and current flowing into the laminated photosensitive member of -10 μA. . The surface potential of the charged layered photoreceptor was measured. The surface potential measured was taken as the charging potential (V ₀ , unit: −V) of the multi-layer photosensitive member. Tables 1 to 3 show the charging potential (V ₀ ) of the layered photosensitive member.

<Evaluation of sensitivity characteristics>
With respect to each of the multi-layer type photosensitive members (A-1) to (A-16) and (B-1) to (B-7), the sensitivity characteristic is obtained under the environment of a temperature of 10.degree. C. and a relative humidity of 20% RH. evaluated. Specifically, the surface of the laminated photosensitive member was charged to -600 V using a drum sensitivity tester (manufactured by Gentec Co., Ltd.). Subsequently, monochromatic light (wavelength: 780 nm, exposure amount: 0.8 μJ / cm ² ) was taken out of the light of the halogen lamp using a band pass filter, and was irradiated to the surface of the multi-layer type photosensitive member. The surface potential of the laminated photosensitive member was measured when 80 milliseconds passed from the end of the monochromatic light irradiation. The measured surface potential was taken as the post-exposure potential (V _L , unit: −V) of the multi-layer photosensitive member. Tables 1 to 3 show the post-exposure potential (V _L ) of the layered photosensitive member.

<Evaluation of wear resistance>
The abrasion resistance was evaluated for each of the charge transport layers of laminated type photoreceptors (A-1) to (A-16) and (B-1) to (B-7). First, the coating solution for charge transport layer prepared in the production of the layered type photoreceptor was applied to a polypropylene sheet (thickness 0.3 mm) wound around an aluminum pipe (diameter 78 mm). The polypropylene sheet coated with the charge transport layer coating solution was dried at 120 ° C. for 40 minutes. Thereby, the charge transport layer (sheet for evaluation) with a film thickness of 20 micrometers was formed on the polypropylene sheet. Subsequently, the evaluation sheet was peeled off from the polypropylene sheet. Then, the peeled evaluation sheet was attached to a wheel (“S-36” manufactured by Taber Co., Ltd.) to obtain a test piece. The mass of the obtained test piece (the weight of the test piece before the abrasion test) M1 was measured.

  Thereafter, the wear test was performed on the test piece. Specifically, the test piece was attached to the rotary table of a rotary abrasion tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.). Then, while a wear wheel with a load of 500 gf (“CS-10” manufactured by Taber) was placed on the test piece, the rotation table was rotated at a rotation speed of 60 rpm, and a wear test of 1000 rotations was performed. Subsequently, the mass M2 of the test piece after the wear test was measured. And the abrasion loss (M1-M2) which is a mass change of the test piece before and behind a test was calculated | required. The measured wear loss is shown in Tables 1 to 3. The smaller the wear loss, the better the wear resistance of the photoreceptor.

In Tables 1 to 3, HTM, resin, V ₀ and V _L respectively indicate a hole transfer agent, a binder resin, a charging potential and a potential after exposure. In Table 1 to Table 3, "-", since the repeating unit (1) and (2) it does not contain one or both indicates that no value of n ₁ / n _2.

Each of laminated type photoreceptors (A-1) to (A-16) contained a polyarylate resin (PA). Specifically, the polyarylate resin contained in each of laminated type photoreceptors (A-1) to (A-16) is a repeating unit (1) (more specifically, a repeating unit (1-1) (1-5), at least a repeating unit (2) and a repeating unit (3). To the number n ₂ of the repeating units (2), the ratio n ₁ / n ₂ number n ₁ of the repeating units (1) was 1.0 or more. Therefore, as is clear from Tables 1 and 2, in the laminated photosensitive members (A-1) to (A-16), the abrasion loss was 4.9 mg or less, and the abrasion resistance was excellent. In addition, in the laminate type photosensitive members (A-1) to (A-16), the abrasion resistance was improved without impairing the charging characteristics and the sensitivity characteristics.

On the other hand, the laminate type photoreceptor (B-1) contained no polyarylate resin (PA). Specifically, in the polyarylate resin (R-A) contained in the laminate type photoreceptor (B-1), the ratio n ₁ / n ₂ was not 1.0 or more. Therefore, as apparent from Table 3, the polyarylate resin (RA) did not dissolve in the solvent for forming the charge transport layer, and the charge transport layer could not be formed. Therefore, in the multi-layer photosensitive member (B-1), it was not possible to evaluate the charging characteristics, the sensitivity characteristics and the abrasion resistance.

  Each of laminated type photoreceptors (B-2) to (B-7) did not contain polyarylate resin (PA). Specifically, the polyarylate resin (R-B) contained in the laminate type photoreceptor (B-2) did not contain the repeating unit (2). The polyarylate resin (R-C) contained in the laminate type photoreceptor (B-3) did not contain the repeating unit (3). The polyarylate resins (R-D) to (R-G) contained in the laminate type photoreceptors (B-4) to (B-7) contain both of the repeating units (1) and (2). It was not. Therefore, as is clear from Table 3, in the laminated photosensitive members (B-2) to (B-7), the abrasion loss was 5.5 mg or more, and the abrasion resistance was inferior.

  From the above, it was shown that the polyarylate resin according to the present invention can improve the abrasion resistance of the photosensitive member when it is contained in the photosensitive layer. Moreover, it was shown that the photoreceptor according to the present invention is excellent in abrasion resistance.

  The polyarylate resin according to the present invention can be used for a photoreceptor. The photoreceptor according to the present invention can be used in an image forming apparatus.

1 electrophotographic photosensitive member 2 conductive substrate 3 photosensitive layer 3a charge generation layer 3b charge transport layer 3c single layer type photosensitive layer 4 intermediate layer 5 protective layer

Claims (9)

At least a repeating unit represented by the general formula (1), a repeating unit represented by the chemical formula (2), and a repeating unit represented by the chemical formula (3);
The ratio n ₁ / n ₂ of the number n ₁ of repeating units represented by the general formula (1) to the number n ₂ of repeating units represented by the chemical formula (2) is 1.0 or more Alilate resin.

(In the general formula (1),
R ¹ and R ² each independently represent a hydrogen atom or a methyl group, R ³ represents a methyl group, and R ⁴ represents a hydrogen atom or an alkyl group having 2 or 3 carbon atoms, or
R ¹ and R ² each represent a methyl group, and R ³ and R ⁴ are bonded to each other to represent a cycloalkylidene group having 5 or 6 carbon atoms. ) The repeating unit represented by the general formula (1) is a repeating unit represented by the chemical formula (1-1), (1-2), (1-3), (1-4) or (1-5) The polyarylate resin according to claim 1, which is

  The polyarylate resin according to claim 2, wherein the repeating unit represented by the general formula (1) is a repeating unit represented by the chemical formula (1-5).   The polyarylate resin according to claim 2, wherein the repeating unit represented by the general formula (1) is a repeating unit represented by the chemical formula (1-1). The polyarylate resin according to claim 4, further comprising a repeating unit represented by Chemical Formula (4).

An electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer,
The photosensitive layer contains a charge generating agent, a hole transporting agent, and a binder resin.
The electrophotographic photosensitive member, wherein the binder resin comprises the polyarylate resin according to any one of claims 1 to 5. The electrophotographic photosensitive member according to claim 6, wherein the hole transport agent comprises a compound represented by the general formula (10), (11), (12), (13) or (14).

(In the general formula (10),
R ¹⁰¹ , R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , R ¹⁰⁶ , R ¹⁰⁷ and R ¹⁰⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms A phenyl group which may have one or more alkoxy groups having 1 to 8 carbon atoms,
Adjacent two of R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ , R ¹⁰⁶ and R ¹⁰⁷ may combine to represent a cycloalkane having 5 to 7 carbon atoms,
R ¹⁰² and R ¹⁰⁹ each independently represent an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms,
Each of b ₁ and b ₂ independently represents an integer of 0 or more and 5 or less. )

(In the general formula (11),
R ¹¹¹ and R ¹¹² each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group,
R ¹¹³ , R ¹¹⁴ , R ¹¹⁵ , R ¹¹⁶ , R ¹¹⁷ and R ¹¹⁸ each independently represent an alkyl group having 1 to 8 carbon atoms or a phenyl group,
d ₁ and d ₂ each independently represent 0 or 1;
d ₃ , d ₄ , d ₅ and d ₆ each independently represent an integer of 0 or more and 5 or less,
d ₇ and d ₈ each independently represent an integer of 0 or more and 4 or less. )

(In the general formula (12),
R ¹²¹ , R ¹²² , R ¹²³ , R ¹²⁴ , R ¹²⁵ and R ¹²⁶ each independently represent an alkyl group having 1 to 8 carbon atoms, a phenyl group or an alkoxy group having 1 to 8 carbon atoms,
Each of e ₁ , e ₂ , e ₄ and e ₅ independently represents an integer of 0 or more and 5 or less,
Each of e ₃ and e ₆ independently represents an integer of 0 or more and 4 or less. )

(In the above general formula (13), R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ³⁷ , R ³⁸ , R ³⁹ and R ^3A each independently represent a hydrogen atom or a methyl group Represent)

(In the above general formula (14), R ⁴¹ and R ⁴² each independently represent a hydrogen atom, a methyl group or an ethyl group, and the carbon atom number of the group represented by R ⁴¹ and the carbon atom of the group represented by R ⁴² The sum of the number and the number is 2, and R ⁴³ and R ⁴⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group, and the carbon atom number of the group represented by R ⁴³ and the carbon atom of the group represented by R ⁴⁴ The sum with the number is 2.) The hole transfer agent is represented by the chemical formulas (HTM-1), (HTM-2), (HTM-3), (HTM-4), (HTM-5), (HTM-6), (HTM-7), The electrophotographic photosensitive member according to claim 6, comprising a compound represented by (HTM-8), (HTM-9), (HTM-10) or (HTM-11).

The photosensitive layer includes a charge generation layer and a charge transport layer,
The charge generating layer contains the charge generating agent,
The electrophotographic photosensitive member according to any one of claims 6 to 8, wherein the charge transport layer contains the hole transport agent and the binder resin.

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