Polyarylate resins and electrophotographic photoreceptors

Abstract

The polyarylate resin has repeating units represented by formulae (1), (2), and (4). The polyarylate resin also has repeating units represented by formula (3) at a content of greater than 0% and less than 50% relative to the total number of repeating units represented by formulae (1) and (3). Alternatively, the polyarylate resin does not have repeating units represented by formula (3). In formula (1), R 1 and R 2 each independently represent a hydrogen atom or a methyl group, and X is a divalent group represented by formula (X1) or (X2). In formula (3), R 5 and R 6 each independently represent a hydrogen atom or a methyl group.

Description

Technical Field

[0001] This invention relates to polyarylate resins and electrophotographic photosensitive materials. Background Technology

[0002] Electrophotographic photosensitive elements serve as image carriers in electrophotographic image forming apparatuses (e.g., printers or multifunction printers). Electrophotographic photosensitive elements possess a photosensitive layer. Examples of electrophotographic photosensitive elements include single-layer electrophotographic photosensitive elements and multilayer electrophotographic photosensitive elements. A single-layer electrophotographic photosensitive element possesses a single photosensitive layer, which has both charge generation and charge transport functions. A multilayer electrophotographic photosensitive element contains a charge generation layer and a charge transport layer; the charge generation layer has a charge generation function, and the charge transport layer has a charge transport function.

[0003] Patent document 1 describes an electrophotographic photosensitive material whose surface layer contains a polyarylate resin obtained from a dicarboxylic acid component and a diphenol component as shown in the following formula.

[0004]

[0005] [Patent Documents]

[0006] Patent Document 1: Japanese Patent Application Publication No. 10-20514 Summary of the Invention

[0007] However, the electrophotographic photosensitive material described in Patent Document 1 is insufficient in terms of abrasion resistance. Furthermore, the inventors have discovered through research that the electrophotographic photosensitive material described in Patent Document 1 is also insufficient in terms of the solubility of the binder resin in solvents and its photosensitivity characteristics under repeated charging and exposure.

[0008] The present invention was made in view of the above-mentioned problems, and its object is to provide a polyaryl ester resin that has excellent solubility in a solvent, and when the polyaryl ester resin is contained in the photosensitive layer of an electrophotographic photosensitive sensor, it improves the photosensitivity characteristics and abrasion resistance of the electrophotographic photosensitive sensor under repeated charging and exposure. Hereinafter, "photosensitivity characteristics under repeated charging and exposure" is sometimes referred to as "repeatability photosensitivity characteristics". Furthermore, another object of the present invention is to provide an electrophotographic photosensitive sensor in which a photosensitive layer can be well formed, and which has excellent repeatability photosensitivity characteristics and abrasion resistance.

[0009] The polyaryl ester resin of the present invention has repeating units shown in formulas (1), (2), and (4). The polyaryl ester resin also has repeating units shown in formula (3), wherein the content of repeating units shown in formula (3) is greater than 0% and less than 50% relative to the total number of repeating units shown in formulas (1) and (3). Alternatively, the polyaryl ester resin does not contain repeating units shown in formula (3).

[0010]

[0011] In the above formula (1), R 1 and R 2 Each is independent, representing a hydrogen atom or a methyl group, and X represents a divalent group as shown in formula (X1) or (X2). In formula (3), R 5 and R 6 Each can be used independently to represent a hydrogen atom or a methyl group.

[0012]

[0013] In equation (X1), t represents an integer between 1 and 3, and * represents a bonding bond. In equation (X2), R 3 and R 4 Each is independent, representing a hydrogen atom or a C1-C4 alkyl group, and * indicates a bond.

[0014] The electrophotographic photoreceptor 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 binding resin. The binding resin contains the aforementioned polyarylate resin.

[0015] [Invention Effects]

[0016] The polyaryl ester resin of the present invention exhibits excellent solubility in solvents, and when the polyaryl ester resin is contained in the photosensitive layer, the repeatability and abrasion resistance of the electrophotographic photoreceptor can be improved. The electrophotographic photoreceptor of the present invention can form a photosensitive layer well and exhibits excellent repeatability and abrasion resistance. Attached Figure Description

[0017] Figure 1 This is a partial cross-sectional view of a stacked electrophotographic photosensitive unit, which is an example of an electrophotographic photosensitive unit according to the second embodiment of the present invention.

[0018] Figure 2 This is a partial cross-sectional view of a stacked electrophotographic photosensitive unit, which is an example of an electrophotographic photosensitive unit according to the second embodiment of the present invention.

[0019] Figure 3This is a partial cross-sectional view of a stacked electrophotographic photosensitive unit, which is an example of an electrophotographic photosensitive unit according to the second embodiment of the present invention.

[0020] Figure 4 This is a partial cross-sectional view of a single-layer electrophotographic photosensitive element, which is an example of an electrophotographic photosensitive element according to the second embodiment of the present invention.

[0021] Figure 5 This is a partial cross-sectional view of a single-layer electrophotographic photosensitive element, which is an example of an electrophotographic photosensitive element according to the second embodiment of the present invention.

[0022] Figure 6 This is a partial cross-sectional view of a single-layer electrophotographic photosensitive element, which is an example of an electrophotographic photosensitive element according to the second embodiment of the present invention.

[0023] Figure 7 It is polyarylate resin F. 1 H-NMR spectrum. Detailed Implementation

[0024] The embodiments of the present invention will now be described in detail. However, the present invention is not limited to the embodiments described below, and appropriate modifications can be made within the scope of the present invention. Furthermore, there are instances where repeated descriptions are appropriately omitted, but this does not limit the essence of the invention. Hereinafter, the term "class" is sometimes added after the compound name to collectively refer to the compound and its derivatives. Also, when "class" is added after the compound name to indicate the name of a polymer, it indicates that the repeating unit of the polymer originates from the compound or its derivatives. Furthermore, "general formula" and "chemical formula" are collectively referred to as "formula". The phrase "each independent" in the description of a formula means that the same base or different bases can be represented. Unless otherwise stated, each component described in this specification can be used individually or in combination of two or more.

[0025] First, the substituents in this specification will be described. Unless otherwise stated, C1-C8 alkyl, C1-C6 alkyl, C1-C4 alkyl and C1-C3 alkyl groups are straight-chain or branched and are unsubstituted. C1-C8 alkyl groups include, for example: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 2-ethylpropyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethylbutyl, 2-ethylbutyl and 3-ethylbutyl, heptyl in straight-chain and branched form, and octyl in straight-chain and branched form. Examples of C1-C6 alkyl, C1-C4 alkyl, and C1-C3 alkyl are examples of C1-C8 alkyl with the corresponding number of carbon atoms.

[0026] Unless otherwise stated, C1-C10 perfluoroalkyl, C3-C10 perfluoroalkyl, C5-C7 perfluoroalkyl, and C6 perfluoroalkyl are all straight-chain or branched and are unsubstituted. Examples of C1-C10 perfluoroalkyl groups include: trifluoromethyl, perfluoroethyl, perfluoron-propyl, perfluoroisopropyl, perfluoron-butyl, perfluorosec-butyl, perfluorotert-butyl, perfluoron-pentyl, perfluoro-1-methylbutyl, perfluoro-2-methylbutyl, perfluoro-3-methylbutyl, perfluoro-1-ethylpropyl, perfluoro-2-ethylpropyl, perfluoro-1,1-dimethylpropyl, perfluoro-1,2-dimethylpropyl, perfluoro-2,2-dimethylpropyl, perfluoron-hexyl, perfluoro-1-methylpentyl, perfluoro-2-methylpentyl, perfluoro-3-methylpentyl, and perfluoro-4-methylpentyl. The examples include perfluoro-1,1-dimethylbutyl, perfluoro-1,2-dimethylbutyl, perfluoro-1,3-dimethylbutyl, perfluoro-2,2-dimethylbutyl, perfluoro-2,3-dimethylbutyl, perfluoro-3,3-dimethylbutyl, perfluoro-1,1,2-trimethylpropyl, perfluoro-1,2,2-trimethylpropyl, perfluoro-1-ethylbutyl, perfluoro-2-ethylbutyl and perfluoro-3-ethylbutyl, linear and branched perfluoroheptyl, linear and branched perfluorooctyl, linear and branched perfluorononyl and linear and branched perfluorodecyl. Examples of C3-C10 perfluoroalkyl, C5-C7 perfluoroalkyl and C6 perfluoroalkyl are each examples of C1-C10 perfluoroalkyl with the corresponding number of carbon atoms.

[0027] Unless otherwise stated, C1-C8 alkoxy and C1-C3 alkoxy are straight-chain or branched and are unsubstituted. C1-C8 alkoxy groups include, for example: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, 1-methylbutoxy, 2-methylbutoxy, 3-methylbutoxy, 1-ethylpropoxy, 2-ethylpropoxy, 1,1-dimethylpropoxy, 1,2-dimethylpropoxy, 2,2-dimethylpropoxy, n-hexyloxy, 1-methylpentoxy, 2-methylpentoxy, 3-methylpentoxy, 4-methylpentoxy, 1,1-dimethylbutoxy, 1,2-dimethylbutoxy, 1,3-dimethylbutoxy, 2,2-dimethylbutoxy, 2,3-dimethylbutoxy, 3,3-dimethylbutoxy, 1,1,2-trimethylpropoxy, 1,2,2-trimethylpropoxy, 1-ethylbutoxy, 2-ethylbutoxy, 3-ethylbutoxy, straight-chain and branched heptoxy groups, and straight-chain and branched octoxy groups. Examples of C1-C3 alkoxy groups are examples of C1-C8 alkoxy groups with the corresponding number of carbon atoms.

[0028] Unless otherwise stated, C5-C7 cycloalkanes are unsubstituted. Examples of C5-C7 cycloalkanes include cyclopentane, cyclohexane, and cycloheptane. The substituents in this specification are described above.

[0029] <First Embodiment: Polyarylate Resin>

[0030] The first embodiment of the present invention relates to a polyarylate resin. The polyarylate resin of the first embodiment has repeating units shown in formulas (1), (2) and (4). The polyarylate resin of the first embodiment also has repeating units shown in formula (3), wherein the content of repeating units shown in formula (3) is greater than 0% and less than 50% relative to the total number of repeating units shown in formulas (1) and (3). Alternatively, the polyarylate resin of the first embodiment does not contain repeating units shown in formula (3).

[0031]

[0032] In equation (1), R 1 and R 2 Each is independent, representing a hydrogen atom or a methyl group, and X represents a divalent group as shown in formula (X1) or (X2). In formula (3), R 5 and R 6 Each can be used independently to represent a hydrogen atom or a methyl group.

[0033]

[0034] In equation (X1), t represents an integer greater than 1 and less than 3, and * represents a bonding bond. In equation (X2), R 3 and R4 Each is independent, representing a hydrogen atom or a C1-C4 alkyl group, and * indicates a bond.

[0035] Hereinafter, the repeating units shown in equations (1), (2), (3), and (4) are sometimes referred to as "repeating units (1), (2), (3), and (4)" respectively. Also, the content of repeating unit (3) relative to the total number of repeating units (1) and (3) is sometimes referred to as "content (3)". Also, polyarylate resins having repeating units (1), (2), and (4) and also having repeating unit (3) with a content (3) greater than 0% and less than 50% or without repeating unit (3) are sometimes referred to as "polyarylate resin (PA)".

[0036] The polyaryl ester resin (PA) must contain repeating units (1), (2) and (4). By having such repeating units, the polyaryl ester resin (PA) has excellent solubility in solvents, and when the photosensitive layer contains polyaryl ester resin (PA), the repeatability and abrasion resistance of the electrophotographic photosensitive material (hereinafter, sometimes referred to as photosensitive material) can be improved.

[0037] The polyaryl ester resin (PA) may not contain repeating units (3). However, in order to improve the repeatability of the photosensitivity of the photoreceptor when the photosensitive layer contains polyaryl ester resin (PA), the polyaryl ester resin (PA) is preferably provided with repeating units (3).

[0038] When the polyaryl ester resin (PA) also contains repeating units (3), the content rate (3) is greater than 0% and less than 50%. The content rate (3) is equivalent to the percentage of the number of repeating units (3) N3 relative to the total number of repeating units (1) N1 and the number of repeating units (3) N3 in the polyaryl ester resin (PA) (i.e., 100×N3 / (N1+N3)). In addition, when the polyaryl ester resin (PA) has two or more types of repeating units (1), the number of repeating units (1) N1 is the total number of the two or more types of repeating units (1). When the polyaryl ester resin (PA) has two or more types of repeating units (3), the number of repeating units (3) N3 is the total number of the two or more types of repeating units (3).

[0039] By making the content (3) less than 50%, the solubility of polyarylate resin (PA) in the solvent is improved. By making the content (3) greater than 0%, that is, the content (3) is not 0%, the repeatability of the photoreceptor when the photosensitive layer contains polyarylate resin (PA) is improved. The content (3) is preferably 1% or more, more preferably 5% or more, further preferably 10% or more, and even more preferably 20% or more. Furthermore, the content (3) is preferably 45% or less, more preferably 40% or less, and even more preferably 30% or less.

[0040] To further improve the solubility of polyarylene resin (PA) in solvent, it is preferable that the polyarylene resin (PA) contains repeating units (3) and the content (3) is greater than 0% and less than 30%.

[0041] The content of repeating unit (4) relative to the total number of repeating units (2) and (4) is greater than 0% and less than 100%. The content of repeating unit (4) relative to the total number of repeating units (2) and (4) is sometimes referred to as "content (4)". Content (4) is equivalent to: the percentage of the number of repeating units (4) N4 relative to the total number of repeating units (2) N2 and repeating units (4) N4 in the polyaryl ester resin (PA) (i.e., 100×N4 / (N2+N4)). Content (4) is greater than 0%, that is, content (4) is not 0%, therefore the polyaryl ester resin (PA) has repeating unit (4). By having repeating unit (4), the repeatability and abrasion resistance of the photosensitive layer containing polyaryl ester resin (PA) are improved. On the other hand, content (4) is less than 100%, that is, content (4) is not 100%, therefore the polyaryl ester resin (PA) has repeating unit (2). By having repeating units (2), the repeatability of the photosensitivity of the photoreceptor is improved when the photosensitive layer contains polyarylate resin (PA). The content (4) is preferably 1% or more, more preferably 10% or more, further preferably 20% or more, even more preferably 30% or more, and particularly preferably 35% or more. Furthermore, the content (4) is preferably 99% or less, more preferably 80% or less, even more preferably 65% ​​or less, even more preferably 50% or less, and particularly preferably 40% or less.

[0042] Measurement of polyarylate resin (PA) using proton nuclear magnetic resonance spectroscopy 1 H-NMR spectra, based on the obtained 1 The ratio of characteristic peaks of each repeating unit in the H-NMR spectrum can be used to calculate the content rates (3) and (4).

[0043] In equation (1), R 1 and R 2 Preferably, it represents a hydrogen atom. Alternatively, in formula (1), R 1 and R 2 Preferably, it represents methyl.

[0044] In equation (X1), t is preferably represented by 2.

[0045] In equation (X2), R 3 and R 4 When C1-C4 alkyl is used, C1-C3 alkyl is preferred, and methyl or ethyl is more preferred.

[0046] In equation (X2), R3 and R 4 Each is independent, preferably representing a C1-C4 alkyl group. R 3 and R 4 Each is independent, and more preferably, it represents C1-C3 alkyl groups. R 3 and R 4 Each is independent, and more preferably represents methyl or ethyl. Particularly preferred is: R 3 Indicates methyl and R 4 It represents ethyl, or R 3 Indicates methyl and R 4 It indicates methyl.

[0047] The bonding bond represented by * in formulas (X1) and (X2) combines with the carbon atom bonded to X in formula (1).

[0048] In order to further improve the repeatability of photosensitivity of the photoreceptor when the photosensitive layer contains polyarylate resin (PA), it is preferable that: in formula (1), X represents the divalent group shown in formula (X1), and in formula (X1), t represents 2.

[0049] In equation (3), R 5 and R 6 Preferably, it represents a hydrogen atom. Alternatively, in formula (3), R 5 and R 6 Preferably, it represents methyl.

[0050] The repeating unit (1) is, for example, the repeating unit shown in equations (1-1), (1-2), (1-3) and (1-4) (hereinafter, sometimes referred to as repeating units (1-1), (1-2), (1-3) and (1-4) respectively).

[0051]

[0052] The repeating unit (1) preferably contains repeating units (1-1), (1-2), or (1-3). More preferably, the repeating unit (1) further contains repeating unit (1-4) in addition to containing repeating units (1-1), (1-2), or (1-3). More preferably, the repeating unit (1) contains both repeating units (1-1) and (1-4).

[0053] The polyaryl ester resin (PA) preferably has at least one repeating unit (1), more preferably has one or more but less than four repeating units (1), and even more preferably has one or two repeating units (1).

[0054] The repeating unit (3) is, for example, the repeating unit shown in equations (3-1) and (3-2) (hereinafter, sometimes referred to as repeating unit (3-1) and (3-2) respectively).

[0055]

[0056] The repeating unit (3) is preferably containing the repeating unit (3-1).

[0057] The polyaryl ester resin (PA) preferably has at least one repeating unit (3), more preferably has one or more but less than three repeating units (3), and even more preferably has one or two repeating units (3).

[0058] When the polyaryl ester resin (PA) has repeating unit (3), the repeating unit (3) preferably contains repeating unit (3-1). When the polyaryl ester resin (PA) has repeating unit (3), it is more preferable that the repeating unit (3) contains repeating unit (3-1) and the repeating unit (1) contains repeating unit (1-1).

[0059] When the polyaryl ester resin (PA) does not contain repeating unit (3), the repeating unit (1) preferably contains repeating units (1-1), (1-2), or (1-3). When the polyaryl ester resin (PA) does not contain repeating unit (3), it is more preferable that the repeating unit (1) contains repeating units (1-1), (1-2), or (1-3), and the repeating unit (1) further contains repeating unit (1-4). When the polyaryl ester resin (PA) does not contain repeating unit (3), it is even more preferable that the repeating unit (1) contains repeating unit (1-1), and the repeating unit (1) further contains repeating unit (1-4).

[0060] In order to further improve the repeatability of the photoreceptor when the photosensitive layer contains polyarylate resin (PA), the polyarylate resin (PA) is preferably free of the repeating unit shown in formula (5).

[0061]

[0062] Polyaryl ester resins (PA) may also have terminal groups. The terminal groups of polyaryl ester resins (PA) are, for example, those shown in formulas (T-1) and (T-2). The terminal group shown in formula (T-1) is preferably the terminal group shown in formula (T-DMP) (hereinafter sometimes referred to as terminal group (T-DMP)). The terminal group shown in formula (T-2) is preferably the terminal group shown in formula (T-PFH) (hereinafter sometimes referred to as terminal group (T-PFH)).

[0063]

[0064] In equation (T-1), R 11 Represents C1-C6 alkyl or halogen atoms, where p represents an integer between 0 and 5. R 11Preferably, it represents a C1-C6 alkyl group, more preferably a C1-C3 alkyl group, and even more preferably a methyl group. p is preferably an integer of 1 to 3, more preferably 2.

[0065] In equation (T-2), R 12 R indicates C1-C6 alkyldiyl, and Rf indicates C1-C10 perfluoroalkyl. 12 Preferably, it represents a C1-C3 alkyldiyl group, more preferably a methylene group. Rf preferably represents a C3-C10 perfluoroalkyl group, more preferably a C5-C7 perfluoroalkyl group, and even more preferably a C6 perfluoroalkyl group.

[0066] The asterisk (*) in formulas (T-1), (T-2), (T-DMP), and (T-PFH) indicates a bonding bond. The bonding bond represented by the asterisk (*) in formulas (T-1), (T-2), (T-DMP), and (T-PFH) is bonded to a repeating unit (more specifically, repeating unit (2) or (4)) located at the end of the polyaryl ester resin (PA) and derived from a dicarboxylic acid.

[0067] Preferred examples of polyaryl ester resins (PA) can be found in Table 1, specifically polyaryl ester resins (PA-1) to (PA-5). Each of the polyaryl ester resins (PA-1) to (PA-5) has repeating units (1) to (4) as shown in Table 1. The meanings of the terms in Table 1 and Table 2, which will be explained later, are as follows: “Unit (1) to (4)” means “repeating units (1) to (4)” respectively. “-” means “does not contain the repeating unit”. “1-1 / 1-4” means “has repeating units (1) and (1-4) as repeating units (1)”.

[0068] Table 1

[0069] Polyaryl resin Unit (1) Unit (2) Unit (3) Unit (4) PA-1 1-1 2 - 4 PA-2 1-2 2 - 4 PA-3 1-3 2 - 4 PA-4 1-1 / 1-4 2 - 4 PA-5 1-1 2 3-1 4

[0070] Further preferred examples of polyaryl ester resins (PA) can be found in Table 2, namely polyaryl ester resins (PA-a) to (PA-j). Each of the polyaryl ester resins (PA-a) to (PA-j) has a repeating unit (1) to (4) as repeating unit in Table 2 and a terminal group in Table 2.

[0071] Table 2

[0072] Polyaryl resin Unit (1) Unit (2) Unit (3) Unit (4) terminal group PA-a 1-1 2 - 4 T-DMP PA-b 1-2 2 - 4 T-DMP PA-c 1-3 2 - 4 T-DMP PA-d 1-1 / 1-4 2 - 4 T-DMP PA-e 1-1 2 3-1 4 T-DMP PA-f 1-1 2 - 4 T-PFH PA-g 1-2 2 - 4 T-PFH PA-h 1-3 2 - 4 T-PFH PA-i 1-1 / 1-4 2 - 4 T-PFH PA-j 1-1 2 3-1 4 T-PFH

[0073] In polyaryl ester resins (PA), repeating units from bisphenol (more specifically, repeating unit (1) or (3)) are adjacent to and bonded to repeating units from dicarboxylic acids (more specifically, repeating unit (2) or (4)). That is, repeating unit (1) can be bonded to repeating unit (2) or repeating unit (4). Also, repeating unit (3) can be bonded to repeating unit (2) or repeating unit (4). The repeating units from bisphenol and repeating units from dicarboxylic acids have approximately the same number, satisfying the calculation formula "number of repeating units from dicarboxylic acids = number of repeating units from bisphenol + 1". Polyaryl ester resins (PA) can be, for example, random copolymers, alternating copolymers, periodic copolymers, or block copolymers.

[0074] In polyaryl ester resin (PA), the repeating units may further include repeating units other than repeating units (1) to (4). However, in order to improve the solubility in the solvent and the repeatability and abrasion resistance of the photoreceptor when the photosensitive layer contains polyaryl ester resin (PA), the content of repeating units (1) to (4) is preferably 90% or more, more preferably 95% or more, more preferably 99% or more, and particularly preferably 100% relative to the total number of repeating units in the polyaryl ester resin (PA). That is, the polyaryl ester resin (PA) is particularly preferably having only repeating units (1) to (4).

[0075] The viscosity-average molecular weight of the polyaryl ester resin (PA) is preferably 10,000 or more, more preferably 30,000 or more, even more preferably 50,000, and particularly preferably 55,000 or more. When the viscosity-average molecular weight of the polyaryl ester resin (PA) is 10,000 or more, the abrasion resistance of the photoreceptor is improved when the photosensitive layer of the photoreceptor contains the polyaryl ester resin (PA). On the other hand, the viscosity-average molecular weight of the polyaryl ester resin (PA) is preferably 80,000 or less, more preferably 70,000 or less, and even more preferably 60,000 or less. When the viscosity-average molecular weight of the polyaryl ester resin (PA) is 80,000 or less, the solubility of the polyaryl ester resin (PA) in solvents is improved. The viscosity-average molecular weight of the polyaryl ester resin (PA) is measured according to JIS (Japanese Industrial Standard) K7252-1:2016.

[0076] Next, a method for manufacturing polyaryl ester resin (PA) will be described. One method for manufacturing polyaryl ester resin (PA) is, for example, the polycondensation of bisphenol (used to form repeating units from bisphenol) and dicarboxylic acid (used to form repeating units from dicarboxylic acid). Polycondensation can be performed using well-known synthetic methods (e.g., solution polymerization, melt polymerization, or interfacial polymerization).

[0077] Bisphenols (used to form repeating units from bisphenols) include, for example, compounds of formulas (BP-1) and (BP-3) (hereinafter sometimes referred to as compounds (BP-1) and (BP-3) respectively). Dicarboxylic acids (used to form repeating units from dicarboxylic acids) include, for example, compounds of formulas (DC-2) and (DC-4) (hereinafter sometimes referred to as compounds (DC-2) and (DC-4) respectively). R in formula (BP-1) 1 R 2 And X and R in equation (1) 1 R 2 R has the same meaning as X. In equation (BP-3), R... 5 and R 6 R in equation (3) 5 and R 6 They have the same meaning.

[0078]

[0079] In the manufacture of polyarylate resin (PA), the content can be adjusted (3) by changing the amount (in moles) of compound (BP-3) relative to the total amount (in moles) of compounds (BP-1) and (BP-3). Furthermore, the content can be adjusted (4) by changing the amount (in moles) of compound (DC-4) relative to the total amount (in moles) of compounds (DC-2) and (DC-4).

[0080] Bisphenols can also be derived from aromatic diacetates. Dicarboxylic acids can also be derived from other compounds. Examples of dicarboxylic acid derivatives include dicarboxylic acid dichloride, dimethyl dicarboxylic acid, diethyl dicarboxylic acid, and dicarboxylic acid anhydrides. Dicarboxylic acid dichloride is a compound in which both "-C(=O)-OH" groups of a dicarboxylic acid are replaced by "-C(=O)-Cl" groups.

[0081] In the polycondensation of bisphenol and dicarboxylic acid, a terminator can also be added. Examples of terminators include 2,6-dimethylphenol and 1H,1H-perfluoro-1-heptanol. Using 2,6-dimethylphenol as a terminator allows the formation of a terminal group (T-DMP). Using 1H,1H-perfluoro-1-heptanol as a terminator allows the formation of a terminal group (T-PFH).

[0082] In the polycondensation of bisphenols and dicarboxylic acids, one or both of a base and a catalyst may be added. Examples of bases include sodium hydroxide. Examples of catalysts include benzyltributylammonium chloride, ammonium chloride, ammonium bromide, quaternary ammonium salts, triethylamine, and trimethylamine.

[0083] <Second Implementation Method: Photoreceptor>

[0084] The second embodiment of the present invention relates to a photoreceptor. The photoreceptor of the second embodiment comprises a conductive substrate and a photosensitive layer. The photosensitive layer contains a charge-generating agent, a hole-transporting agent, and a binding resin. The photoreceptor is, for example, a single-layer electrophotographic photoreceptor (hereinafter, sometimes referred to as a single-layer photoreceptor) or a multilayer electrophotographic photoreceptor (hereinafter, sometimes referred to as a multilayer photoreceptor).

[0085] (Layered photoreceptor)

[0086] The following is for reference Figures 1-3 The laminated photoreceptor 1, which is an example of a photoreceptor, will be described. Figures 1-3 Each represents a partial cross-sectional view of the stacked photoreceptor 1.

[0087] like Figure 1 As shown, the stacked photoreceptor 1 includes, for example, a conductive substrate 2 and a photosensitive layer 3. The photosensitive layer 3 includes a charge generation layer 3a and a charge transport layer 3b. That is, in the stacked photoreceptor 1, the photosensitive layer 3 includes a charge generation layer 3a and a charge transport layer 3b. The charge generation layer 3a is, for example, a single layer. The charge transport layer 3b is, for example, a single layer.

[0088] like Figure 1 As shown, a charge generation layer 3a can be disposed on the conductive substrate 2, and a charge transport layer 3b can be disposed on the charge generation layer 3a. Alternatively, as... Figure 2 As shown, a charge transport layer 3b can also be provided on the conductive substrate 2, and a charge generation layer 3a can be provided on the charge transport layer 3b.

[0089] like Figure 3 As shown, the laminated photoreceptor 1 can also further include an intermediate layer 4 (base layer) on top of the conductive substrate 2 and the photosensitive layer 3. The intermediate layer 4 is disposed between the conductive substrate 2 and the photosensitive layer 3. Figure 1 and Figure 2 As shown, in the laminated photoreceptor 1, the photosensitive layer 3 can be directly on the conductive substrate 2. Alternatively, as... Figure 3 As shown, in the stacked photoreceptor 1, the photosensitive layer 3 can also be placed on the conductive substrate 2 with an intermediate layer 4 in between. When the stacked photoreceptor 1 includes an intermediate layer 4, as... Figure 3 As shown, an intermediate layer 4 can be disposed on the conductive substrate 2, a charge generation layer 3a can be disposed on the intermediate layer 4, and a charge transport layer 3b can be disposed on the charge generation layer 3a. Alternatively, an intermediate layer 4 can be disposed on the conductive substrate 2, a charge transport layer 3b can be disposed on the intermediate layer 4, and a charge generation layer 3a can be disposed on the charge transport layer 3b.

[0090] The laminated photoreceptor 1 can also have a protective layer 5 (see reference) on the basis of the conductive substrate 2 and the photosensitive layer 3. Figure 6The protective layer 5 is disposed on the photosensitive layer 3. For example... Figures 1-3 As shown, the photosensitive layer 3 (e.g., charge transport layer 3b or charge generation layer 3a) can serve as the outermost surface layer of the stacked photoreceptor 1. Alternatively, the protective layer 5 can also serve as the outermost surface layer of the stacked photoreceptor 1.

[0091] like Figure 1 As shown, the photosensitive layer 3 (preferably the charge transport layer 3b) is preferably used as the outermost surface layer of the laminated photoreceptor 1. More preferably, the charge transport layer 3b is a single layer and serves as the outermost surface layer of the laminated photoreceptor 1. By using the charge transport layer 3b containing polyaryl ester resin (PA) as the outermost surface layer, the wear resistance of the laminated photoreceptor 1 is further improved.

[0092] The charge generating layer 3a contains a charge generating agent. The charge generating layer 3a may also contain a matrix resin, if desired. The charge generating layer 3a may also contain additives, if desired. The thickness of the charge generating layer 3a is not particularly limited, but is preferably 0.01 μm to 5 μm, more preferably 0.1 μm to 3 μm.

[0093] The charge transport layer 3b contains a hole transport agent and a binding resin. Depending on the need, the charge transport layer 3b may also contain additives. The thickness of the charge transport layer 3b is not particularly limited, but is preferably 2 μm to 100 μm, more preferably 5 μm to 50 μm. As described above, refer to... Figures 1-3 This describes the layered photoreceptor 1.

[0094] (Single-layer photoreceptor)

[0095] Next, refer to Figures 4-6 The single-layer photoreceptor 10, which is an example of a photoreceptor, will be described. Figures 4-6 Each is a partial cross-sectional view of a single-layer photoreceptor 10.

[0096] like Figure 4 As shown, the single-layer photoreceptor 10 includes, for example, a conductive substrate 2 and a photosensitive layer 3. The photosensitive layer 3 of the single-layer photoreceptor 10 is single-layered. Hereinafter, "single-layered photosensitive layer 3" is sometimes referred to as "single-layered photosensitive layer 3c".

[0097] like Figure 5 As shown, based on the conductive substrate 2 and the monolayer photosensitive layer 3c, the monolayer photoreceptor 10 may further include an intermediate layer 4 (base layer). The intermediate layer 4 is disposed between the conductive substrate 2 and the monolayer photosensitive layer 3c. Figure 4 As shown, the single-layer photosensitive layer 3c can be directly applied to the conductive substrate 2. Alternatively, as... Figure 5 As shown, the single-layer photosensitive layer 3c can also be placed on the conductive substrate 2 with an intermediate layer 4 in between.

[0098] like Figure 6 As shown, based on the conductive substrate 2 and the single-layer photosensitive layer 3c, the single-layer photoreceptor 10 may further include a protective layer 5. The protective layer 5 is disposed on the single-layer photosensitive layer 3c. For example... Figure 4 and Figure 5 As shown, the single-layer photosensitive layer 3c can serve as the outermost surface layer of the single-layer photoreceptor 10. Alternatively, as... Figure 6 As shown, the protective layer 5 can also serve as the outermost surface layer of the single-layer photoreceptor 10.

[0099] like Figure 4 and Figure 5 As shown, the photosensitive layer 3 (more specifically, the single-layer photosensitive layer 3c) is preferably used as the outermost surface layer of the single-layer photoreceptor 10. By using the single-layer photosensitive layer 3c containing polyaryl ester resin (PA) as the outermost surface layer, the wear resistance of the single-layer photoreceptor 10 is further improved.

[0100] The single-layer photosensitive layer 3c contains a charge-generating agent, a hole-transporting agent, and a binding resin. If necessary, the single-layer photosensitive layer 3c may further contain an electron-transporting agent. If necessary, the single-layer photosensitive layer 3c may also contain additives.

[0101] The thickness of the single-layer photosensitive layer 3c is not particularly limited, but is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm. As described above, refer to... Figures 4-6 This illustrates the single-layer photoreceptor 10.

[0102] (Adhesive resin)

[0103] The adhesive resin contains the polyaryl ester resin (PA) described in the first embodiment. By using the polyaryl ester resin (PA), which has excellent solubility in solvents, the photosensitive layer of the photoreceptor can be formed well. Furthermore, by containing the polyaryl ester resin (PA) in the photosensitive layer, the repeatability and abrasion resistance of the photoreceptor are improved.

[0104] In the photosensitive layer, the binder resin may contain only one type of polyaryl ester resin (PA), or it may contain two or more types of polyaryl ester resin (PA). Furthermore, in the photosensitive layer, the binder resin may contain only polyaryl ester resin (PA), or it may further contain binder resins other than polyaryl ester resin (PA) (hereinafter, sometimes referred to as other binder resins). Other bonding resins include: thermoplastic resins (more specifically, polyarylene resins other than polyarylene resins (PA), polycarbonate resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, styrene-acrylic acid copolymers, acrylic acid copolymers, polyethylene resins, ethylene-vinyl acetate copolymers, chlorinated polyethylene resins, polyvinyl chloride resins, polypropylene resins, ionomers, vinyl chloride-vinyl acetate copolymers, polyester resins, alkyd resins, polyamide resins, polyurethane resins, polysulfone resins, diallyl phthalate resins, ketone resins, polyvinyl butyral resins, polyvinyl acetal resins, and polyether resins), thermosetting resins (more specifically, silicone resins, epoxy resins, phenolic resins, urea-formaldehyde resins, melamine resins, and other crosslinked thermosetting resins), and photocurable resins (more specifically, epoxy-acrylic resins and polyurethane-acrylic copolymers).

[0105] (Cavitation delivery agent)

[0106] Hole delivery agents include, for example, triphenylamine derivatives and diamine derivatives (e.g., N,N,N',N'-tetraphenylbenzidine derivatives, N,N,N',N'-tetraphenylphenyldiamine derivatives, N,N,N',N'-tetraphenylnaphthalenediamine derivatives, N,N,N',N'-tetraphenylphenanthrylenediamine). The photosensitive layer may contain only one type of hole transporter, or two or more types of hole transporters. These include diamine derivatives and di(aminophenylvinyl)benzene derivatives, oxadiazoles (e.g., 2,5-di(4-methylaminophenyl)-1,3,4-oxadiazole), styrene compounds (e.g., 9-(4-diethylaminostyryl)anthracene), carbazoles (e.g., polyvinylcarbazole), organopolysilanes, pyrazoline compounds (e.g., 1-phenyl-3-(p-dimethylaminophenyl)pyrazoline), hydrazones, indole compounds, oxazoles, isoxazoles, thiazoles, thiadiazoles, imidazoles, pyrazoles, and triazoles.

[0107] Preferred examples of hole delivery agents include compounds represented by formulas (20), (21), and (22) (hereinafter sometimes referred to as hole delivery agents (20), (21), and (22) respectively). By containing polyarylate resin (PA) and hole delivery agents (20), (21), or (22) in the photosensitive layer, the photosensitive layer can be formed even better, and the repeatability and abrasion resistance of the photoreceptor are further improved.

[0108]

[0109] In equation (20), R 21 and R 22 Each can be independent and represents a C1-C8 alkyl, phenyl, or C1-C8 alkoxy group. R 23 R 24 R 25 R 26 R 27 R 28 and R 29 Each can be independent and represent a hydrogen atom, a C1-C8 alkyl group, a C1-C8 alkoxy group, a phenyl group with a C1-C8 alkyl substituent, or an unsubstituted phenyl group. R 25 R 26 R 27 R 28 and R 29 Two adjacent elements in the array either do not bond to each other or are bonded to each other to form a ring. a1 and a2 are independent and represent integers above 0 and below 5.

[0110] In equation (20), a1 represents a number of R integers greater than 2 and less than 5. 21 They can be from the same base or different bases. When a2 represents integers greater than 2 and less than 5, several R... 22 They can be the same base or different bases.

[0111] In equation (20), R 21 and R 22 Each is independent, preferably representing C1-C8 alkyl, more preferably representing C1-C3 alkyl, and even more preferably representing methyl.

[0112] In equation (20), R 23 and R 24 Each is independent, preferably a phenyl group representing a hydrogen atom, having C1-C8 alkyl substituents, or an unsubstituted phenyl group. R 23 and R 24When referring to a phenyl with C1-C8 alkyl substituents or an unsubstituted phenyl, it is preferably a phenyl with C1-C8 alkyl substituents, more preferably a phenyl with C1-C3 alkyl substituents, even more preferably a methylphenyl, and particularly preferably a 4-methylphenyl.

[0113] In equation (20), R 25 ~R 29 Each is independent, preferably representing a hydrogen atom or a C1-C8 alkoxy group. R 25 ~R 29 When representing C1-C8 alkoxy, C1-C3 alkoxy is preferred, and methoxy or ethoxy is more preferred. In R 25 ~R 29 In the case where two adjacent bonds in the middle form a ring, this ring is related to R. 25 ~R 29 The combined phenyl group undergoes condensation to form a bicyclic fused ring. In this case, the condensation site between the ring and the phenyl group can also contain a double bond. In R 25 ~R 29 When two adjacent bonds form a ring, such a ring is preferably a C5-C7 cycloalkane, and more preferably cyclohexane.

[0114] In equation (20), a1 and a2 are independent and preferably represent 0 or 1.

[0115] In equation (21), R 31 R 32 R 33 R 34 R 35 and R 36 Each can be independent and represents a C1-C8 alkyl or phenyl group. R 37 and R 38 Each of the following pairs represents a hydrogen atom, a C1-C8 alkyl group, or a phenyl group. b1, b2, b3, and b4 each represent an integer between 0 and 5. b5 and b6 each represent an integer between 0 and 4. d and e each represent 0 or 1.

[0116] In equation (21), b1 represents a number of R integers greater than 2 and less than 5. 31 They can be from the same base or different bases. When b2 represents integers greater than 2 and less than 5, several R... 32 They can be from the same base or different bases. When b3 represents integers greater than 2 and less than 5, several R... 33 They can be from the same base or different bases. When b4 represents integers greater than 2 and less than 5, several R... 34 They can be from the same base or different bases. When b5 represents integers greater than 2 and less than 4, several R...35 They can be from the same base or different bases. When b6 represents integers greater than 2 and less than 4, several R... 36 They can be the same base or different bases.

[0117] In equation (21), R 31 ~R 36 Each is independent, preferably representing a C1-C8 alkyl group, more preferably a C1-C3 alkyl group, and even more preferably a methyl or ethyl group. R 37 and R 38 Preferably, they represent hydrogen atoms. b1, b2, b3, and b4 are independent and preferably represent integers greater than 0 and less than 2. b5 and b6 preferably represent 0.

[0118] In equation (22), R 41 R 42 R 43 R 44 R 45 and R 46 Each of these is independent and represents a C1-C8 alkyl, phenyl, or C1-C8 alkoxy group. f1, f2, f4, and f5 are independent and represent integers greater than 0 and less than 5. f3 and f6 are independent and represent integers greater than 0 and less than 4.

[0119] In equation (22), f1 represents several R when the integer is greater than 2 and less than 5. 41 They can be from the same basis or different bases. When f2 represents integers greater than 2 and less than 5, several R... 42 They can have the same basis or different bases. When f4 represents integers greater than 2 and less than 5, several R... 44 They can have the same basis or different bases. When f5 represents integers greater than 2 and less than 5, several R... 45 They can have the same basis or different bases. When f3 represents integers greater than 2 and less than 4, several R... 43 They can have the same base or different bases. When f6 represents integers greater than 2 and less than 4, several R... 46 They can be the same base or different bases.

[0120] In equation (22), R 41 ~R 46 Each is independent, preferably representing a C1-C8 alkyl group, more preferably a C1-C3 alkyl group, and even more preferably a methyl or ethyl group. f1, f2, f4, and f5 are each independent, preferably representing an integer from 0 to 2. f3 and f6 preferably represent 0. Having R 44 R 45 and R46 The diphenylaminostyrene group is preferably: relative to the group having R 41 R 42 and R 43 The diphenylaminostyrene group is bonded to the para position of the phenyl group.

[0121] Further preferred examples of hole delivery agents include compounds represented by formulas (HTM-1) to (HTM-6) (hereinafter, sometimes referred to as hole delivery agents (HTM-1) to (HTM-6)).

[0122]

[0123]

[0124] When the photoreceptor is a multilayer photoreceptor, the content of the hole transporter relative to 100 parts by weight of the binder resin is preferably 10 parts by weight or more and 200 parts by weight or less, more preferably 20 parts by weight or more and 100 parts by weight or less, and even more preferably 40 parts by weight or more and 60 parts by weight or less. When the photoreceptor is a single-layer photoreceptor, the content of the hole transporter relative to 100 parts by weight of the binder resin is preferably 50 parts by weight or more and 200 parts by weight or less, more preferably 50 parts by weight or more and 70 parts by weight or less.

[0125] (charge generator)

[0126] Examples of charge-generating agents include: phthalocyanine pigments, perylene pigments, diazo pigments, triazo pigments, dithioketo-pyrrolopyrrole pigments, metal-free naphthalene phthalocyanine pigments, metal naphthalene phthalocyanine pigments, squaric acid pigments, indigo pigments, chamomile blue pigments, cyanine pigments, inorganic photoconductive materials (e.g., selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, and amorphous silicon) powders, pyran pigments, anthraquinone-anthraquinone pigments, triphenylmethane pigments, vat pigments, toluidine pigments, pyrazoline pigments, and quinacridone pigments. The photosensitive layer may contain only one charge-generating agent or two or more charge-generating agents.

[0127] Phthalocyanine pigments are pigments with a phthalocyanine structure. Examples of phthalocyanine pigments include metal-free phthalocyanines and metallic phthalocyanines. Examples of metallic phthalocyanines include titanium dioxide phthalocyanine, hydroxygallium phthalocyanine, and gallium chloride phthalocyanine. Metal-free phthalocyanines are represented by formula (CGM-1). Titanium dioxide phthalocyanines are represented by formula (CGM-2).

[0128]

[0129]

[0130] Phthalocyanine pigments can be crystalline or amorphous. Crystalline metal-free phthalocyanines include, for example, type X crystals of metal-free phthalocyanines (hereinafter sometimes referred to as type X metal-free phthalocyanine). Crystalline titanium phthalocyanines include, for example, type α, type β, and type Y crystals of titanium phthalocyanines (hereinafter sometimes referred to as type α, type β, and type Y titanium phthalocyanines, respectively).

[0131] For example, in digital optical image forming apparatuses (e.g., laser printers or fax machines using light sources such as semiconductor lasers), a photoreceptor with photosensitivity in the wavelength region of 700 nm and above is preferred. From the viewpoint of having high quantum yield in the wavelength region of 700 nm and above, the charge generating agent is preferably a phthalocyanine pigment, more preferably a metal-free phthalocyanine or titanium phthalocyanine, further preferably titanium phthalocyanine, and particularly preferably Y-type titanium phthalocyanine.

[0132] Y-type titanium phthalocyanine exhibits a dominant peak in the characteristic X-ray diffraction spectrum of CuKα, for example, at a Bragg angle of 27.2° (2θ ± 0.2°). A dominant peak in the characteristic X-ray diffraction spectrum of CuKα refers to the peak with the first or second largest intensity in the range of 3° to 40° within the Bragg angle (2θ ± 0.2°). In the characteristic X-ray diffraction spectrum of CuKα, Y-type titanium phthalocyanine shows no peak at 26.2℃.

[0133] The characteristic X-ray diffraction spectrum of CuKα can be measured, for example, by the following method. First, a sample (titanium phthalocyanine) is filled into the sample holder of an X-ray diffraction apparatus (RINT 1100 manufactured by Rigaku Corporation). The X-ray tube is Cu, the tube voltage is 40 kV, the tube current is 30 mA, and the characteristic X-ray wavelength of CuKα is... Under the given conditions, measure the X-ray diffraction spectrum. The measurement range (2θ) is, for example, 3° to 40° (starting angle 3°, stopping angle 40°), and the scanning speed is, for example, 10° / min. Determine the main peak based on the obtained X-ray diffraction spectrum and read the Bragg angle of the main peak.

[0134] When the photoreceptor is a laminated photoreceptor, the content of the charge-generating agent is preferably 10 parts by mass or more and 300 parts by mass or less, more preferably 100 parts by mass or more and 200 parts by mass or less, relative to 100 parts by mass of the matrix resin. When the photoreceptor is a monolayer photoreceptor, the content of the charge-generating agent is preferably 0.1 parts by mass or more and 50 parts by mass or less, more preferably 0.5 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0135] (Matrix resin)

[0136] Examples of matrix resins contained in the charge generation layer are the same as examples of other binder resins contained in the charge transport layer.

[0137] (additive)

[0138] Additives include, for example, ultraviolet absorbers, antioxidants, free radical scavengers, singlet quenchers, softeners, surface modifiers, extenders, thickeners, dispersants, waxes, donors, surfactants, plasticizers, sensitizers, electron acceptor compounds, and leveling agents. The leveling agent is preferably silicone oil, more preferably silicone oil having a polydimethylsiloxane structure.

[0139] (Combination of materials)

[0140] To ensure proper formation of the photosensitive layer and improve the repeatability and abrasion resistance of the photoreceptor, the combination of hole transporter and binder resin is preferably each of the combinations No. a-1 to a-30 and b-1 to b-60 in Table 3 and combinations No. c-1 to c-60 in Table 4. For the same reason, it is preferable that the combination of hole transporter and binder resin is each of the combinations No. a-1 to a-30 and b-1 to b-60 in Table 3 and combinations No. c-1 to c-60 in Table 4, and the charge generating agent is Y-type titanium phthalocyanine. For the same reason, it is more preferable that the combination of hole transporter and binder resin is each of the combinations No. a-1 to a-30 and b-1 to b-60 in Table 3 and combinations No. c-1 to c-60 in Table 4, and the additive contained in the charge transport layer is m-terphenyl. For the same reason, it is more preferable that the combination of hole transporter and binder resin is each of combinations No. a-1 to a-30 and b-1 to b-60 in Table 3 and combinations No. c-1 to c-60 in Table 4, and the additive contained in the charge transport layer is silicone oil (more specifically, silicone oil having a polydimethylsiloxane structure). In Tables 3 and 4, "No." means "combination No.", "HTM" means "hole transporter", and "resin" means "polyaryl ester resin" as binder resin. Polyaryl ester resins A to J in Table 4 will be described in detail in the examples.

[0141] Table 3

[0142] No. HTM resin No. HTM resin NO. HTM resin a-1 HTM-1 PA-1 b-1 HTM-1 PA-a b-31 HTM-1 PA-f a-2 HTM-2 PA-1 b-2 HTM-2 PA-a b-32 HTM-2 PA-f a-3 HTM-3 PA-1 b-3 HTM-3 PA-a b-33 HTM-3 PA-f a-4 HTM-4 PA-1 b-4 HTM-4 PA-a b-34 HTM-4 PA-f a-5 HTM-5 PA-1 b-5 HTM-5 PA-a b-35 HTM-5 PA-f a-6 HTM-6 PA-1 b-6 HTM-6 PA-a b-36 HTM-6 PA-f a-7 HTM-1 PA-2 b-7 HTM-1 PA-b b-37 HTM-1 PA-g a-8 HTM-2 PA-2 b-8 HTM-2 PA-b b-38 HTM-2 PA-g a-9 HTM-3 PA-2 b-9 HTM-3 PA-b b-39 HTM-3 PA-g a-10 HTM-4 PA-2 b-10 HTM-4 PA-b b-40 HTM-4 PA-g a-11 HTM-5 PA-2 b-11 HTM-5 PA-b b-41 HTM-5 PA-g a-12 HTM-6 PA-2 b-12 HTM-6 PA-b b-42 HTM-6 PA-g a-13 HTM-1 PA-3 b-13 HTM-1 PA-c b-43 HTM-1 PA-h a--14 HTM-2 PA-3 b-14 HTM-2 PA-c b-44 HTM-2 PA-h a-15 HTM-3 PA-3 b-15 HTM-3 PA-c b-45 HTM-3 PA-h a-16 HTM-4 PA-3 b-16 HTM-4 PA-c b-46 HTM-4 PA-h a-17 HTM-5 PA-3 b-17 HTM-5 PA-c b-47 HTM-5 PA-h a-18 HTM-6 PA-3 b-18 HTM-6 PA-c b-48 HTM-6 PA-h a-19 HTM-1 PA-4 b-19 HTM-1 PA-d b-49 HTM-1 PA-i a-20 HTM-2 PA-4 b-20 HTM-2 PA-d b-50 HTM-2 PA-i a-21 HTM-3 PA-4 b-21 HTM-3 PA-d b-51 HTM-3 PA-i a-22 HTM-4 PA-4 b-22 HTM-4 PA-d b-52 HTM-4 PA-i a-23 HTM-5 PA-4 b-23 HTM-5 PA-d b-53 HTM-5 PA-i a-24 HTM-6 PA-4 b-24 HTM-6 PA-d b-54 HTM-6 PA-i a-25 HTM-1 PA-5 b-25 HTM-1 PA-e b-55 HTM-1 PA-j a-26 HTM-2 PA-5 b-26 HTM-2 PA-e b-56 HTM-2 PA-j a-27 HTM-3 PA-5 b-27 HTM-3 PA-e b-57 HTM-3 PA-j a-28 HTM-4 PA-5 b-28 HTM-4 PA-e b-58 HTM-4 PA-j a-29 HTM-5 PA-5 b-29 HTM-5 PA-e b-59 HTM-5 PA-j a-30 HTM-6 PA-5 b-30 HTM-6 PA-e b-60 HTM-6 PA-j

[0143] Table 4

[0144]

[0145] (Conductive substrate)

[0146] The conductive substrate need only have at least its surface portion formed of a conductive material, and there are no particular limitations. An example of a conductive substrate is one made of a conductive material. Another example is a conductive substrate coated with a conductive material. Examples of conductive materials include aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass. Among these conductive materials, aluminum or aluminum alloys are preferred, based on the viewpoint of good charge movement from the photosensitive layer to the conductive substrate.

[0147] The shape of the conductive substrate is appropriately selected based on the structure of the image forming apparatus. Examples of conductive substrate shapes include sheet-like and drum-like shapes. Furthermore, the thickness of the conductive substrate is appropriately selected based on its shape.

[0148] (Middle layer)

[0149] The intermediate layer (base layer) may contain inorganic particles and a resin used in the intermediate layer (resin for intermediate layer). It can be considered that the presence of the intermediate layer can maintain an insulating state that can suppress leakage, while allowing the current generated during exposure of the photosensitive material to flow smoothly, thereby suppressing the increase in resistance.

[0150] Inorganic particles include, for example, particles of metals (e.g., aluminum, iron, and copper), particles of metal oxides (e.g., titanium dioxide, aluminum oxide, zirconium oxide, tin oxide, and zinc oxide), and particles of non-metal oxides (e.g., silicon dioxide).

[0151] Examples of resins used in the intermediate layer are the same as those for the other adhesive resins described above. To ensure proper formation of both the intermediate layer and the photosensitive layer, the resin used in the intermediate layer is preferably different from the adhesive resin contained in the photosensitive layer. The intermediate layer may also contain additives. Examples of additives contained in the intermediate layer are the same as those contained in the photosensitive layer.

[0152] (Methods for manufacturing photoreceptors)

[0153] Regarding the manufacturing method of photoreceptors, an example of a manufacturing method for a laminated photoreceptor and an example of a manufacturing method for a single-layer photoreceptor will be described.

[0154] A method for manufacturing a laminated photoreceptor includes, for example, a charge generation layer formation step and a charge transport layer formation step. In the charge generation layer formation step, firstly, a coating solution for forming the charge generation layer (hereinafter, sometimes referred to as a charge generation layer coating solution) is prepared. The charge generation layer coating solution is then coated onto a conductive substrate. Then, at least a portion of the solvent contained in the charge generation layer coating solution is removed, thereby forming the charge generation layer. The charge generation layer coating solution, for example, contains a charge generating agent, a matrix resin, and a solvent. Such a charge generation layer coating solution is prepared by dissolving or dispersing the charge generating agent and the matrix resin in a solvent. If necessary, the charge generation layer coating solution may further contain additives.

[0155] In the charge transport layer formation process, firstly, a coating solution for forming the charge transport layer (hereinafter sometimes referred to as a coating solution for charge transport layers) is prepared. The coating solution for charge transport layers is then applied onto the charge generation layer. Next, at least a portion of the solvent contained in the applied coating solution for charge transport layers is removed, thereby forming the charge transport layer. The coating solution for charge transport layers contains a hole transport agent, a binder resin, and a solvent. The coating solution for charge transport layers can be prepared by dissolving or dispersing the hole transport agent, binder resin, and additives in a solvent. If necessary, the coating solution for charge transport layers may further contain additives.

[0156] A method for manufacturing a single-layer photoreceptor includes, for example, a single-layer photoreceptor forming step. In the single-layer photoreceptor forming step, a coating solution for forming the single-layer photoreceptor (hereinafter, sometimes referred to as a coating solution for a single-layer photoreceptor) is prepared. The single-layer photoreceptor coating solution is applied onto a conductive substrate. Then, at least a portion of the solvent contained in the coated photoreceptor coating solution is removed, thereby forming a single-layer photoreceptor. The single-layer photoreceptor coating solution, for example, contains a charge-generating agent, a hole-transporting agent, a binding resin, and a solvent. The single-layer photoreceptor coating solution is prepared by dissolving or dispersing the charge-generating agent, hole-transporting agent, and binding resin in a solvent. If necessary, the single-layer photoreceptor coating solution may further contain one or both of an electron transporter and an additive.

[0157] The solvents contained in coating solutions for single-layer photosensitive layers, charge-generating layers, and charge-transporting layers (hereinafter, sometimes collectively referred to as coating solutions) are not particularly limited, as long as they can dissolve or disperse the components contained in the coating solution. Examples of solvents include: alcohols (more specifically, methanol, ethanol, isopropanol, and butanol), aliphatic hydrocarbons (more specifically, n-hexane, octane, and cyclohexane), aromatic hydrocarbons (more specifically, benzene, toluene, and xylene), halogenated hydrocarbons (more specifically, dichloromethane, dichloroethane, carbon tetrachloride, and chlorobenzene), ethers (more specifically, dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether), ketones (more specifically, acetone, methyl ethyl ketone, and cyclohexanone), esters (more specifically, ethyl acetate and methyl acetate), dimethylformaldehyde, dimethylformamide, and dimethyl sulfoxide.

[0158] The solvent contained in the coating solution for the charge transport layer is preferably different from the solvent contained in the coating solution for the charge generation layer. The reason for this is that, when the coating solution for the charge transport layer is applied to the charge generation layer, it is preferable to use a solvent in which the charge generation layer does not dissolve in the coating solution for the charge transport layer.

[0159] The coating liquid is prepared by mixing and dispersing the various components in a solvent. For example, a bead mill, roller mill, ball mill, grinder, paint vibrator, or ultrasonic disperser can be used for mixing or dispersing.

[0160] Any method that can evenly coat the surface with a coating liquid is acceptable; there are no particular limitations. Examples of coating methods include dip coating, spray coating, spin coating, and rod coating.

[0161] Methods for removing at least a portion of the solvent contained in the coating solution include, for example, heating, depressurization, or a combination of heating and depressurization. More specifically, heat treatment (hot air drying) using a high-temperature dryer or a depressurization dryer can be cited. The temperature of the heat treatment is, for example, between 40°C and 150°C. The time of the heat treatment is, for example, between 3 minutes and 120 minutes.

[0162] Furthermore, the manufacturing method of the photoreceptor may, as needed, include one or both of an intermediate layer formation process and a protective layer formation process. Well-known methods can be appropriately selected for the intermediate layer formation process and the protective layer formation process.

[0163]

Example

[0164] The present invention will now be described in more detail using examples. However, the present invention is not limited in any way to the scope of the examples.

[0165] <Preparation of polyarylate resins A to N>

[0166] The polyarylate resins A to J involved in the examples and the polyarylate resins K to N involved in the comparative examples were synthesized using the following methods. The compositions of polyarylate resins A to N are shown in Table 5 below.

[0167] Table 5

[0168]

[0169] In Table 5, “BisCZ”, “BisB”, “BisC”, “BisZ”, “DHPE”, “DPEC”, “14NACC” and “26NACC” represent the compounds shown by the following formulas (BisCZ), (BisB), (BisC), (BisZ), (DHPE), (DPEC), (14NACC) and (26NACC) respectively (hereinafter, they are sometimes referred to as compounds (BisCZ), (BisB), (BisC), (BisZ), (DHPE), (DPEC), (14NACC) and (26NACC) respectively).

[0170]

[0171] Furthermore, the meanings of the terms in Table 5 are as follows.

[0172] Monomer: The monomer used in the synthesis of polyarylate resins

[0173] Forming unit: A repeating unit formed from this monomer.

[0174] Resin: Polyarylate resin

[0175] Bisphenol addition rate: The percentage (in moles) of the amount of bisphenol monomer added relative to the total amount (in moles) of bisphenol monomer added in the synthesis of polyarylate resin.

[0176] Dicarboxylic acid addition rate: The percentage (in moles) of the amount of dicarboxylic acid monomer added relative to the total amount (in moles) of dicarboxylic acid monomer added in the synthesis of polyarylate resin.

[0177] Molecular weight: Viscosity-average molecular weight

[0178] Unit: Repeating unit

[0179] DMP: 2,6-Dimethylphenol

[0180] PFH: 1H,1H-perfluoro-1-heptanol

[0181] (Synthesis of polyarylate resin A)

[0182] A three-necked flask equipped with a thermometer, a three-way valve, and a dropping funnel was used as the reaction vessel. In the reaction vessel, the monomeric compound (BisCZ) (41.0 mmol), 2,6-dimethylphenol (0.413 mmol) as a terminator, sodium hydroxide (98 mmol), and benzyltributylammonium chloride (0.384 mmol) were added. The air in the reaction vessel was purged with argon. 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 to 10 °C to obtain an alkaline aqueous solution, SA.

[0183] Next, dichloride dicarboxylic acid dichloride (20.8 mmol) of the monomeric compound (DPEC) and dichloride dicarboxylic acid dichloride (11.2 mmol) of the monomeric compound (14NACC) were dissolved in chloroform (150 mL). Thus, chloroform solution SB was obtained.

[0184] Compared to the alkaline aqueous solution SA, a chloroform solution SB was slowly added dropwise over 110 minutes using a dropping funnel. The temperature (liquid temperature) of the contents of the reaction vessel was adjusted to 15±5℃, and the contents of the reaction vessel were stirred for 4 hours to carry out the polymerization reaction. Using a decanter, the upper layer (aqueous layer) of the contents of the reaction vessel was removed to obtain the organic layer. Then, 400 mL of ion-exchanged water was added to an Erlenmeyer flask. The obtained organic layer was then added to the Erlenmeyer flask. Chloroform (400 mL) and acetic acid (2 mL) were further added to the Erlenmeyer flask. The contents of the Erlenmeyer flask were stirred at room temperature (25℃) for 30 minutes. Using a decanter, the upper layer (aqueous layer) of the contents of the Erlenmeyer flask was removed to obtain the organic layer. The obtained organic layer was washed with ion-exchanged water (1 L) using a separatory funnel. The washing with ion-exchanged water was repeated 5 times to obtain a water-washed organic layer. Next, the water-washed organic layer was filtered to obtain the filtrate. The resulting filtrate was slowly added dropwise to methanol (1 L), yielding a precipitate. The precipitate was then removed by filtration. The removed precipitate was then vacuum-dried at 70°C for 12 hours. This yielded polyarylate resin A.

[0185] (Synthesis of polyarylate resins B-N)

[0186] In addition to using the monomers listed in Table 5 at the addition rates shown, each of polyarylate resins B through N was synthesized according to the synthesis method for polyarylate resin A. Furthermore, the addition amounts of each bisphenol monomer were set to ensure a total bisphenol monomer content of 41.0 mmol, achieving the bisphenol addition rates shown in Table 5. For example, in the synthesis of polyarylate resin E, the addition amount of compound (BisCZ) was 32.8 mmol (=41.0×80 / 100), and the addition amount of compound (DHPE) was 8.2 mmol (=41.0×20 / 100). Also, the addition amounts of each dicarboxylic acid monomer were set to ensure a total dicarboxylic acid monomer content of 32.0 mmol, achieving the dicarboxylic acid addition rates shown in Table 5. For example, in the synthesis of polyarylate resin E, the amount of compound (DPEC) added is 12.8 mmol (=32.0×40 / 100), the amount of compound (14NACC) added is 12.8 mmol (=32.0×40 / 100), and the amount of compound (26NACC) added is 6.4 mmol (=32.0×20 / 100).

[0187] The polyarylate resins A to N were measured using a proton nuclear magnetic resonance spectrometer (manufactured by NEC Corporation, 600MHz). 1 1H-NMR spectra. Deuterated chloroform was used as the solvent. Tetramethylsilane (TMS) was used as the internal standard. Representative examples of polyarylene resins A-N: Polyarylene resin F. 1 H-NMR spectra indicate that Figure 7 According to from 1 The chemical shifts read from the H-NMR spectrum confirmed the presence of polyarylate resin F. Polyarylate resins A-E and G-N were also confirmed using the same method.

[0188] <Preparation of Polyarylate Resin O>

[0189] Prepare the polyarylate resin O involved in the comparative example. Polyarylate resin O is represented by the following formula (O). The subscript number of the repeating unit from bisphenol in formula (O) indicates the percentage (in %) of the repeating unit from bisphenol relative to the total number of repeating units from bisphenol contained in polyarylate resin O. Also, the subscript number of the repeating unit from dicarboxylic acid in formula (O) indicates the percentage (in %) of the repeating unit from dicarboxylic acid relative to the total number of repeating units from dicarboxylic acid contained in polyarylate resin O. Polyarylate resin O has terminal groups derived from 2,6-dimethylphenol. The viscosity-average molecular weight of polyarylate resin O is 54,400.

[0190]

[0191] <Measurement of viscosity-average molecular weight>

[0192] The viscosity-average molecular weight of the polyarylate resin was measured according to JIS (Japanese Industrial Standard) K7252-1:2016. The measured viscosity-average molecular weights are shown in Table 5.

[0193] <Manufacturing of Layered Photoreceptors>

[0194] (Manufacturing of the laminated photoreceptor (A-1))

[0195] First, an intermediate layer is formed. Surface-treated titanium dioxide (Tayca Co., Ltd., "Pilot Production Sample SMT-A", number-average primary particle size 10 nm) is prepared. After surface-treating the titanium dioxide with alumina and silica, it is then wet-dispersed while simultaneously surface-treated with polymethylhydrosiloxane, resulting in SMT-A. Next, using a bead mill, 2 parts by weight of SMT-A, 1 part by weight of polyamide resin (Toray Industries, Ltd., "AMILAN (Japanese Registered Trademark) CM8000", a quaternary copolymer polyamide resin of polyamide 6, polyamide 12, polyamide 66, and polyamide 610), 10 parts by weight of methanol, 1 part by weight of butanol, and 1 part by weight of toluene are mixed for 5 hours to obtain a coating solution for the intermediate layer. The coating solution for the intermediate layer is filtered using a 5 μm pore size filter. Then, the coating solution for the intermediate layer is applied to the surface of a conductive substrate using a dip-coating method. An aluminum drum-shaped support was used as the conductive substrate. Next, the intermediate layer on the coating was dried with a coating solution at 130°C for 30 minutes to form an intermediate layer (film thickness: 1 μm) on the conductive substrate.

[0196] Next, a charge-generating layer is formed. Specifically, using a bead mill, 1.5 parts by weight of Y-type titanium phthalocyanine (as a charge-generating agent), 1.0 parts by weight of polyvinyl acetal resin (manufactured by Sekisui Chemicals Co., Ltd., "S-LEC BX-5") (as a matrix resin), 40.0 parts by weight of propylene glycol monomethyl ether, and 40.0 parts by weight of tetrahydrofuran are mixed for 2 hours to obtain a coating solution for the charge-generating layer. The coating solution for the charge-generating layer is filtered using a filter with a pore size of 3 μm. The obtained filtrate is coated onto the intermediate layer using a dip-coating method and dried at 50°C for 5 minutes. Thus, a charge-generating layer (film thickness: 0.3 μm) is formed on the intermediate layer.

[0197] Next, a charge transport layer is formed. Specifically, 50.00 parts by weight of hole transport agent (HTM-1), 100.00 parts by weight of polyarylate resin F as a binder resin, 5.00 parts by weight of m-terphenyl, 0.05 parts by weight of silicone oil (Shin-Etsu Chemical Industry Co., Ltd. "KF96-50cs", a silicone oil with a polydimethylsiloxane structure), 595.00 parts by weight of tetrahydrofuran, and 105.00 parts by weight of toluene are mixed to obtain a coating solution for the charge transport layer. The coating solution for the charge transport layer is applied to the charge generation layer using a dip-coating method and dried in a drying oven for 70 minutes. The heating conditions of the drying oven are: initial temperature 60°C, final temperature 130°C, and heating rate 1°C / min. In this way, a charge transport layer (film thickness: 20 μm) is formed on the charge generation layer, resulting in a laminated photoreceptor (A-1). In the stacked photoreceptor (A-1), the intermediate layer is on a conductive substrate, the charge generation layer is on the intermediate layer, and the charge transport layer is on the charge generation layer.

[0198] (Manufacturing of stacked photoreceptors (A-2) to (A-15) and (B-1) to (B-5))

[0199] In addition to using the hole transporter and polyarylate resin in Table 7, laminated photoreceptors (A-2) to (A-15) and (B-1) to (B-5) were manufactured according to the manufacturing method of laminated photoreceptor (A-1).

[0200] <Evaluation of solubility in solvents>

[0201] At 22°C, 3g of polyaryl ester resin and a amount of tetrahydrofuran (to achieve a polyaryl ester resin concentration of 15% by mass) were stirred for 60 minutes to obtain an evaluation solution. The evaluation solution was visually inspected, and the solubility of the polyaryl ester resin in tetrahydrofuran (as a solvent) was evaluated according to the following criteria. Polyaryl ester resins evaluated as A or B were deemed to have good solubility in the solvent, while polyaryl ester resin evaluated as C was deemed to have poor solubility in the solvent. The evaluation results for each polyaryl ester resin are shown in Table 6.

[0202] (Evaluation criteria for solubility in solvents)

[0203] A: The polyarylate resin was completely dissolved in tetrahydrofuran, and no turbidity or gelation was observed in the evaluation solution.

[0204] B: The turbidity of the evaluation solution was confirmed, but the gelation of the evaluation solution was not confirmed.

[0205] C: The gelation of the evaluation solution has been confirmed.

[0206] <Evaluation of Charged Characteristics>

[0207] The charging characteristics of the photoreceptors were evaluated under conditions of 25°C and 50% RH. Specifically, a drum-type photosensitivity tester (manufactured by GENTEC Corporation) was used to charge the surface of the photoreceptors under conditions of a charging current of -10 μA flowing through the charger and a rotational speed of 31 rpm. The surface potential of the charged photoreceptors was measured. The measured surface potential is recorded as the charged potential of the photoreceptor (V0, unit -V). The charged potentials of each photoreceptor are shown in Table 7. A charged potential between -700V and -650V indicates that the photoreceptor possesses sufficient charging characteristics for practical use.

[0208] <Evaluation of initial sensitivity characteristics and repeat sensitivity characteristics>

[0209] The photosensitivity characteristics of the photoreceptor were evaluated under conditions of 25°C and 50% RH. Specifically, a drum photosensitivity tester (manufactured by GENTEC Corporation) was used, in which the photoreceptor was rotated while being repeatedly charged and exposed. The charging condition was to bring the surface potential of the photoreceptor to -600V. The exposure condition involved using a bandpass filter to extract monochromatic light (wavelength 780nm, exposure dose 0.8μJ / cm²) from the halogen lamp light. 2 The light is shone onto the surface of the photoreceptor. On the 10th rotation of the photoreceptor, 80 milliseconds after the start of exposure (monochromatic light), the surface potential of the photoreceptor is measured, and this is taken as the post-exposure potential (V10) after the 10th rotation. L (Unit: V). Furthermore, at the 1860th rotation of the photoreceptor, 80 milliseconds after the start of exposure (monochromatic light), the surface potential of the photoreceptor is measured as the post-exposure potential (V) after the 1860th rotation. L (Unit: V). The post-exposure potentials for the 10th and 1860th exposures of each photoreceptor are shown in Table 7. Based on the post-exposure potential of the 10th exposure, the initial sensitivity characteristics of the photoreceptor are evaluated according to the following criteria. Furthermore, based on the post-exposure potential of the 1860th exposure, the repeatability sensitivity characteristics of the photoreceptor are evaluated according to the following criteria.

[0210] (Evaluation criteria for initial photosensitivity characteristics)

[0211] Good: The absolute value of the potential after the 10th exposure is below 90V.

[0212] Defect: The absolute value of the potential exceeds 90V after the 10th exposure.

[0213] (Evaluation criteria for repeatability characteristics)

[0214] Good: The absolute value of the potential after exposure ring 1860 is below 120V.

[0215] Defect: The absolute value of the potential after exposure ring 1860 exceeds 120V.

[0216] <Evaluation of Abrasion Resistance>

[0217] The charge transport layer prepared in the above-described "Manufacturing of a Laminated Photoreceptor" was coated onto a polypropylene sheet (thickness: 0.3 mm) wound around an aluminum tube (diameter: 78 mm). The coated charge transport layer was dried in a drying oven for 70 minutes. The oven heating conditions were: initial temperature 60°C, final temperature 130°C, and a heating rate of 1°C / min. After drying, a polypropylene sheet with a charge transport layer (film thickness 30 μm) was produced. Next, the charge transport layer was peeled off from the polypropylene sheet. The peeled charge transport layer was then attached to a card-shaped component (TABER "S-36"). The mass M of the card-shaped component with the attached charge transport layer was measured. A Then, the clip-shaped component was mounted onto the rotary table of a rotary abrasion testing machine (Toyo Seiki Co., Ltd.). Next, with a 500gf-load grinding wheel (TABER CS-10) placed on the photosensitive layer of the clip-shaped component, the rotary table was rotated 1000 times at 60 rpm. This caused wear to the charge transport layer on the rotary table. After wear, the mass M of the clip-shaped component with the charge transport layer attached was measured again. B Next, the mass change of the charge transport layer before and after wear is calculated, i.e., the wear amount (= M). A -M B (Unit: mg). The measured wear amount is shown in Table 7. Based on the wear amount, the abrasion resistance of the photoreceptor is evaluated according to the following criteria.

[0218] (Evaluation criteria for wear resistance)

[0219] Good: Wear amount is below 7.5mg.

[0220] Failure: Wear exceeds 7.5mg.

[0221] In Table 6, "resin" refers to polyarylate resin, and "solubility" indicates the evaluation of the solubility of polyarylate resin in solvents. The terms in Table 7 have the following meanings: "Photoreceptor" refers to a layered photoreceptor. "HTM" refers to a hole transporter. "Resin" refers to polyarylate resin. "Charged" indicates the evaluation of charged properties. "Sensitivity" indicates the evaluation of photosensitivity properties. "V0" indicates the charged potential. The "V0" in the "10th cycle" column... L "This indicates the post-exposure potential of the photoreceptor on the 10th exposure cycle." The "V" in the "1860th cycle" column indicates this. L"This indicates the post-exposure potential of the photoreceptor at the 1860th exposure. "Coating solution cannot be prepared" means that the polyarylate resin is not soluble in the solvent used to form the coating solution for the charge transport layer, and therefore the charge transport layer coating solution cannot be prepared.

[0222] Table 6

[0223] resin Solubility A A B A C A D A E A F A G B H A I A J A K C L A M A N A O A

[0224] Table 7

[0225]

[0226] As shown in Table 5, polyaryl ester resins K to N are not resins included in polyaryl ester resin (PA). Furthermore, as shown in formula (O), polyaryl ester resin O is not a resin included in polyaryl ester resin (PA). Therefore, as shown in Tables 6 and 7, polyaryl ester resin K has poor solubility in solvents, and a coating solution for the charge transport layer could not be prepared using polyaryl ester resin K, thus failing to form a photosensitive layer (more specifically, a charge transport layer). Furthermore, as shown in Table 7, the repeatability of the photoreceptor was not improved when the photosensitive layer contained polyaryl ester resins L and M. Furthermore, as shown in Table 7, the abrasion resistance of the photoreceptor was not improved when the photosensitive layer contained polyaryl ester resin N. Furthermore, as shown in Table 7, the abrasion resistance and repeatability of the photoreceptor were not improved when the photosensitive layer contained polyaryl ester resin O.

[0227] On the other hand, as shown in Table 5, polyaryl ester resins A to J are resins contained in polyaryl ester resin (PA). Therefore, as shown in Table 6, polyaryl ester resins A to J have good solubility in solvents. Furthermore, as shown in Table 7, when the photosensitive layer contains polyaryl ester resins A to J, the repeatability and abrasion resistance of the photoreceptor are improved. Also, as shown in Table 7, when the photosensitive layer contains polyaryl ester resins A to J, the charge characteristics and initial photosensitivity of the photoreceptor are not impaired, and the repeatability and abrasion resistance of the photoreceptor are improved.

[0228] As can be seen from the above, the polyaryl ester resins of the present invention, including polyaryl ester resins A to J, exhibit excellent solubility in solvents. When such polyaryl ester resins are contained in the photosensitive layer, the repeatability and abrasion resistance of the photoreceptor can be improved. Furthermore, the photoreceptors of the present invention, including the laminated photoreceptors (A-1) to (A-15), exhibit the ability to form a photosensitive layer well and improve repeatability and abrasion resistance.

[0229] [Industry Availability]

[0230] The photoreceptor involved in this invention can be used in an image forming apparatus.

Claims

1. A polyarylate resin, Having repeating units as shown in equations (1), (2) and (4), It also has repeating units as shown in equation (3), wherein, relative to the total number of repeating units shown in equations (1) and (3), the content of repeating units shown in equation (3) is greater than 0% and less than 30%. In the above formula (1), R 1 and R 2 Each is independent, representing a hydrogen atom or a methyl group, where X is a divalent group as shown in formula (X1) or (X2). In equation (3), R 5 and R 6 Each can be used independently to represent either a hydrogen atom or a methyl group. In the formula (X1), t represents an integer between 1 and 3, and * represents a bonding bond. In the formula (X2), R 3 and R 4 Each is independent, representing a hydrogen atom or a C1-C4 alkyl group, and * indicates a bond.

2. The polyarylate resin according to claim 1, characterized in that, It does not have the repeating unit shown in equation (5), 3. The polyarylate resin according to claim 1, characterized in that, In equation (1), X is the divalent base represented by equation (X1), and t represents 2.

4. The polyarylate resin according to claim 1, characterized in that, It also has the repeating unit shown in equation (3), wherein the repeating unit shown in equation (3) contains the repeating unit shown in equation (3-1). The repeating unit shown in equation (1) contains the repeating unit shown in equation (1-1).

5. The polyarylate resin according to claim 1, characterized in that, The repeating unit shown in equation (1) contains repeating units shown in equations (1-1), (1-2), or (1-3).

6. An electrophotographic photosensitive material, It has a conductive substrate and a photosensitive layer. The photosensitive layer contains a charge-generating agent, a hole-transporting agent, and a binding resin. The adhesive resin comprises the polyarylate resin according to claim 1.

7. The electrophotographic photosensitive material according to claim 6, characterized in that, The cavitation delivery agent contains a compound represented by formula (20), (21), or (22). In equation (20), R 21 and R 22 Each is independent, representing C1-C8 alkyl, phenyl, or C1-C8 alkoxy, R 23 ~R 29 Each can be represented independently as a hydrogen atom, a C1-C8 alkyl group, a C1-C8 alkoxy group, a phenyl group with a C1-C8 alkyl substituent, or an unsubstituted phenyl group, R 25 ~R 29 In a given set, two adjacent elements either do not bond to each other or bond to each other to form a ring. a1 and a2 are independent and represent integers greater than 0 and less than 5. In the above equation (21), R 31 ~R 36 Each is independent, representing C1-C8 alkyl or phenyl groups, R 37 and R 38 Each of the following is independent and represents a hydrogen atom, a C1-C8 alkyl group, or a phenyl group; b1, b2, b3, and b4 are independent and represent integers from 0 to 5; b5 and b6 are independent and represent integers from 0 to 4; d and e are independent and represent 0 or 1. In equation (22), R 41 ~R 46 Each is independent and represents C1-C8 alkyl, phenyl, or C1-C8 alkoxy. f1, f2, f4, and f5 are independent and represent integers above 0 and below 5. f3 and f6 are independent and represent integers above 0 and below 4.

8. The electrophotographic photosensitive material according to claim 6, characterized in that, The cavitation delivery agent contains a compound represented by formula (HTM-1), (HTM-2), (HTM-3), (HTM-4), (HTM-5), or (HTM-6).

9. The electrophotographic photosensitive material according to claim 6, characterized in that, The photosensitive layer comprises a charge generating layer and a charge transport layer. The charge generating layer contains the charge generating agent, and the charge transport layer contains the hole transport agent and the binding resin. The charge transport layer is a single layer and serves as the outermost surface layer.

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