Electrophotographic photoreceptor, process cartridge, and image forming device

Abstract

The present invention provides an electrophotographic photoreceptor, a processing box and an image forming device. The photosensitive layer of the electrophotographic photoreceptor is a single layer and contains a charge generating agent, a hole transporting agent, a first electron transporting agent, a second electron transporting agent and a binding resin. The binding resin contains a polyarylate resin. The polyarylate resin has repeating units (1), (2), (3) and (4). Relative to the total number of repeating units (1) and (3), the content of repeating unit (3) is greater than 0% and less than 20%. The first electron transporting agent contains a compound represented by formula (A15) or (A16). The second electron transporting agent contains a compound represented by formula (B10), (B11), (B12), (B13) or (B14).

Description

Technical Field

[0001] The present invention relates to an electronic photographic photoreceptor, a process cartridge and an image forming device. Background Art

[0002] An electrophotographic photoreceptor is used as an image carrier in an electrophotographic image forming device (e.g., a printer or a multifunction device). The electrophotographic photoreceptor has a photosensitive layer. Examples of electrophotographic photoreceptors include single-layer electrophotographic photoreceptors and laminated electrophotographic photoreceptors. A single-layer electrophotographic photoreceptor has a single-layer photosensitive layer, and the single-layer photosensitive layer has a charge generating function and a charge transporting function. The photosensitive layer in the laminated electrophotographic photoreceptor contains a charge generating layer and a charge transporting layer, and the charge generating layer has a charge generating function, and the charge transporting layer has a charge transporting function.

[0003] For example, an electrophotographic photoreceptor is known whose surface layer contains a polyarylate resin obtained from a dicarboxylic acid component and a dihydric phenol component represented by the following formula.

[0004] Summary of the invention

[0005] However, the present inventors have found through studies that the above-mentioned electrophotographic photoreceptors are insufficient in terms of good formation of a photosensitive layer, charging stability, and suppression of transfer memory.

[0006] The present invention has been made in view of the above problems, and its object is to provide an electrophotographic photoreceptor in which a photosensitive layer is well formed, the electrophotographic photoreceptor has excellent charging stability and can suppress transfer memory. In addition, another object of the present invention is to provide a process cartridge and an image forming apparatus equipped with an electrophotographic photoreceptor in which a photosensitive layer is well formed, the electrophotographic photoreceptor has excellent charging stability and can suppress transfer memory.

[0007] The electrophotographic photoreceptor of the present invention comprises a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer. The photosensitive layer contains a charge generating agent, a hole transporting agent, a first electron transporting agent, a second electron transporting agent and a binder resin. The binder resin contains a polyarylate resin. The polyarylate resin has repeating units represented by formulas (1), (2), (3) and (4). Relative to the total number of repeating units represented by formulas (1) and (3), the content of the repeating unit represented by formula (3) is greater than 0% and less than 20%. The first electron transporting agent contains a compound represented by formula (A15) or (A16). The second electron transporting agent contains a compound represented by formula (B10), (B11), (B12), (B13) or (B14).

[0008]

[0009] In the formula (1), R 1 and R 2 Each independently represents a hydrogen atom or a methyl group, and X represents a divalent group represented by formula (X1) or (X2). In the above formula (2), W represents a divalent group represented by formula (W1) or (W2).

[0010]

[0011] In the formula (X1), t represents an integer of 1 to 3, and * represents a bond. 3 and R 4 represents a hydrogen atom or a C1-C4 alkyl group, R 3 and R 4 denotes different groups, and * denotes a bond.

[0012]

[0013] In the formula (W1) and the formula (W2), * represents a bond.

[0014]

[0015] Q in the formula (A15) 51 , Q 52 , Q 53 , Q 54 , Q 55 and Q 56 , Q in the formula (A16) 61 and Q 62 , Q in the formula (B10) 1 and Q 2 , Q in the formula (B11) 11 , Q 12 and Q 13 , Q in the formula (B12) 21 , Q 22 , Q 23 and Q 24 , Q in the formula (B13) 31 and Q 32 And Q in the formula (B14) 41 , Q 42 , Q 43 and Q 44Each independently represents a hydrogen atom, a halogen atom, a cyano group, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C1-C6 alkoxy group, an unsubstituted C6-C14 aryl group, or a C6-C14 aryl group substituted with at least one substituent selected from the group consisting of a C1-C6 alkyl group and a halogen atom. 1 and Y 2 Each independently represents an oxygen atom or a sulfur atom.

[0016] The process cartridge of the present invention comprises at least one device selected from the group consisting of a charging device, an exposure device, a developing device, a transfer device, a cleaning device and an antistatic device, and the above-mentioned electrophotographic photoreceptor.

[0017] The image forming apparatus of the present invention comprises: an image bearing body; a charging device for charging the surface of the image bearing body; an exposure device for exposing the charged surface of the image bearing body to form an electrostatic latent image on the surface of the image bearing body; a developing device for supplying a toner to the surface of the image bearing body to develop the electrostatic latent image into a toner image; and a transfer device for transferring the toner image from the image bearing body to a transferee. The image bearing body is the above-mentioned electrophotographic photosensitive body.

[0018] The electrophotographic photoreceptor of the present invention has a photosensitive layer well formed therein, has excellent charging stability and can suppress transfer memory. In addition, the process cartridge and image forming apparatus of the present invention include an electrophotographic photoreceptor, in which a photosensitive layer is well formed, has excellent charging stability and can suppress transfer memory. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a partial cross-sectional view of the electrophotographic photoreceptor according to the first embodiment of the present invention.

[0020] Figure 2 It is a partial cross-sectional view of the electrophotographic photoreceptor according to the first embodiment of the present invention.

[0021] Figure 3 It is a partial cross-sectional view of the electrophotographic photoreceptor according to the first embodiment of the present invention.

[0022] Figure 4 This is an example of the structure of the image forming apparatus according to the second embodiment of the present invention.

[0023] Figure 5 yes Figure 4 An example of the structure of the developing device in.

[0024] Figure 6It is polyarylate resin H 1 H-NMR spectrum. DETAILED DESCRIPTION

[0025] Hereinafter, the embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented after appropriate changes within the scope of the purpose of the present invention. In addition, there are cases where repeated descriptions are appropriately omitted, but the gist of the invention is not limited. Hereinafter, "class" is sometimes added after the compound name to collectively refer to the compound and its derivatives. In addition, when "class" is added after the compound name to indicate the name of a polymer, it means that the repeating unit of the polymer is derived from the compound or its derivative. In addition, "general formula" and "chemical formula" are collectively referred to as "formula". "Each independently" in the description of the formula means that it can represent the same group or different groups. Unless otherwise specified, each component described in this specification can be used alone or in combination of two or more.

[0026] First, the substituents used in the present specification are described. Examples of the halogen atom (halogen group) include a fluorine atom (fluoro group), a chlorine atom (chloro group), a bromine atom (bromo group), and an iodine atom (iodo group).

[0027] Unless otherwise specified, C1-C6 alkyl, C1-C5 alkyl, C1-C4 alkyl, C1-C3 alkyl and C3 alkyl are all linear or branched and unsubstituted. Examples of the C1-C6 alkyl group include 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. Examples of the C1-C5 alkyl group, the C1-C4 alkyl group, the C1-C3 alkyl group and the C3 alkyl group are each a group having the corresponding number of carbon atoms in the examples of the C1-C6 alkyl group.

[0028] Unless otherwise specified, C1-C10 perfluoroalkyl, C3-C10 perfluoroalkyl, C5-C7 perfluoroalkyl and C6 perfluoroalkyl are all linear or branched and unsubstituted. Examples of C1-C10 perfluoroalkyl include trifluoromethyl, perfluoroethyl, perfluoro-n-propyl, perfluoro-isopropyl, perfluoro-n-butyl, perfluoro-sec-butyl, perfluoro-tert-butyl, perfluoro-n-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, perfluoro-n-hexyl, perfluoro-1-methylpentyl, perfluoro-2-methylpentyl, perfluoro-3-methylpentyl, perfluoro-4-methylbutyl. Examples of the C3-C10 perfluoroalkyl group, C5-C7 perfluoroalkyl group and C6 perfluoroalkyl group are perfluoro-1,1-dimethylbutyl group, perfluoro-1,2-dimethylbutyl group, perfluoro-1,3-dimethylbutyl group, perfluoro-2,2-dimethylbutyl group, perfluoro-2,3-dimethylbutyl group, perfluoro-3,3-dimethylbutyl group, perfluoro-1,1,2-trimethylpropyl group, perfluoro-1,2,2-trimethylpropyl group, perfluoro-1-ethylbutyl group, perfluoro-2-ethylbutyl group and perfluoro-3-ethylbutyl group, linear and branched perfluoroheptyl group, linear and branched perfluorooctyl group, linear and branched perfluorononyl group and linear and branched perfluorodecyl group. Examples of the C3-C10 perfluoroalkyl group, C5-C7 perfluoroalkyl group and C6 perfluoroalkyl group are groups having the corresponding number of carbon atoms in the examples of the C1-C10 perfluoroalkyl group.

[0029] Unless otherwise specified, C1-C6 alkylidene and C1-C3 alkylidene are straight-chain or branched and unsubstituted. Examples of C1-C6 alkylidene include methylidene, ethylidene, n-propylidene, isopropylidene, n-butylidene, sec-butylidene, tert-butylidene, n-pentylidene, 1-methylbutylidene, 2-methylbutylidene, 3-methylbutylidene, 1-ethylpropylidene, 2-ethylpropylidene, 1,1-dimethylpropylidene, 1,2-dimethylpropylidene, 2,2-dimethylpropylidene, n-hexylidene, 1-methylpentylide ...2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, 2-ethylbutylidene, Examples of the C1-C3 alkylidene group are groups having the corresponding number of carbon atoms in the examples of the C1-C6 alkylidene group.

[0030] Unless otherwise specified, the C1-C6 alkoxy group and the C1-C3 alkoxy group are linear or branched and unsubstituted. Examples of the C1-C6 alkoxy group include 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 and 3-ethylbutoxy. Examples of the C1-C3 alkoxy group are groups having the corresponding number of carbon atoms as in the examples of the C1-C6 alkoxy group.

[0031] Unless otherwise specified, a C2-C6 alkenyl group is straight-chain or branched and unsubstituted. A C2-C6 alkenyl group has one or more and three or less double bonds. Examples of C2-C6 alkenyl groups include ethenyl, propenyl, butenyl, butadienyl, pentenyl, hexenyl, hexadienyl and hexatriynyl.

[0032] Unless otherwise specified, C6-C14 aryl and C6-C10 aryl are unsubstituted. Examples of C6-C14 aryl include phenyl, naphthyl, indacenyl, biphenylenyl, acenaphthylenyl, anthracenyl and phenanthrenyl. Examples of C6-C10 aryl include phenyl and naphthyl. As described above, the substituents used in this specification are explained.

[0033] <First Embodiment: Electrophotographic Photoreceptor>

[0034] The first embodiment relates to an electrophotographic photoreceptor (hereinafter, sometimes referred to as a photoreceptor). Figure 1 to Figure 3 , the structure of the electrophotographic photoreceptor according to the first embodiment of the present invention is described. Figure 1 to Figure 3 Each is a partial cross-sectional view of the photoreceptor 1 .

[0035] like Figure 1 As shown, the photoreceptor 1 includes, for example, a conductive substrate 2 and a photosensitive layer 3. The photosensitive layer 3 is a single layer. The photoreceptor 1 is a single-layer type electrophotographic photoreceptor including the single-layer photosensitive layer 3.

[0036] like Figure 2As shown in FIG. 1 , the photoreceptor 1 may further include an intermediate layer 4 (undercoat layer) in addition to the conductive substrate 2 and the photosensitive layer 3. The intermediate layer 4 is provided between the conductive substrate 2 and the photosensitive layer 3. Figure 1 As shown, the photosensitive layer 3 can be directly on the conductive substrate 2. Alternatively, as Figure 2 As shown, the photosensitive layer 3 may also be on the conductive substrate 2 via the intermediate layer 4 .

[0037] like Figure 3 As shown in FIG. 1 , the photoreceptor 1 may further include a protective layer 5 in addition to the conductive substrate 2 and the photosensitive layer 3. The protective layer 5 is provided on the photosensitive layer 3. Figure 3 As shown, the protective layer 5 can be used as the outermost surface layer of the photoreceptor 1. However, as Figure 1 and Figure 2 As shown, the photosensitive layer 3 is preferably used as the outermost layer of the photoreceptor 1. By using the photosensitive layer 3 containing the polyarylate resin (PA) described later as the outermost layer, the charging stability of the photoreceptor 1 is improved and the transfer memory is suppressed.

[0038] The thickness of the photosensitive layer 3 is not particularly limited, but is preferably 5 μm to 100 μm, and more preferably 10 μm to 50 μm. Figure 1 to Figure 3 The structure of the photoreceptor 1 is described.

[0039] The photoreceptor is further described below. The photosensitive layer in the photoreceptor contains a charge generating agent, a hole transporting agent, a first electron transporting agent, a second electron transporting agent, and a binder resin. The photosensitive layer may further contain additives as needed.

[0040] (Charge Generator)

[0041] Examples of the charge generating agent include phthalocyanine pigments, perylene pigments, disazo pigments, trisazo pigments, dithioketo-pyrrolopyrrole pigments, metal-free naphthalocyanine compounds, metal naphthalocyanine compounds, squaric acid pigments, indigo pigments, azulene pigments, cyanine pigments, powders of inorganic photoconductive materials (e.g., selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, and amorphous silicon), pyran pigments, anthraquinone pigments, triphenylmethane pigments, threne pigments, toluidine pigments, pyrazoline pigments, and quinacridone pigments. The photosensitive layer may contain only one charge generating agent, or may contain two or more charge generating agents.

[0042] Phthalocyanine pigments are pigments having a phthalocyanine structure. Examples of phthalocyanine pigments include metal phthalocyanines and metal-free phthalocyanines. Examples of metal phthalocyanines include oxytitanium phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine. Metal phthalocyanine is preferably oxytitanium phthalocyanine. Oxytitanium phthalocyanine is represented by formula (CG-1). Metal-free phthalocyanine is represented by formula (CG-2).

[0043]

[0044] Phthalocyanine pigments may be crystalline or amorphous. Examples of crystalline metal-free phthalocyanine include X-type crystals of metal-free phthalocyanine (hereinafter, sometimes described as X-type metal-free phthalocyanine). Examples of crystalline oxytitanium phthalocyanine include α-type, β-type and Y-type crystals of oxytitanium phthalocyanine (hereinafter, sometimes described as α-type, β-type and Y-type oxytitanium phthalocyanine, respectively).

[0045] For example, in a digital optical image forming device (e.g., a laser printer or a fax machine using a light source such as a semiconductor laser), it is preferred to use a photoreceptor having sensitivity in a wavelength region of 700 nm or more. From the viewpoint of having a high quantum yield in a wavelength region of 700 nm or more, the charge generating agent is preferably a phthalocyanine pigment, more preferably a metal-free phthalocyanine or an oxytitanium phthalocyanine, further preferably an oxytitanium phthalocyanine, and particularly preferably a Y-type oxytitanium phthalocyanine.

[0046] Y-type oxytitanium phthalocyanine has a main peak at, for example, 27.2° of the Bragg angle (2θ±0.2°) in the CuKα characteristic X-ray diffraction spectrum. The main peak in the CuKα characteristic X-ray diffraction spectrum refers to a peak with the first or second largest intensity in the range of the Bragg angle (2θ±0.2°) from 3° to 40°. In the CuKα characteristic X-ray diffraction spectrum, Y-type oxytitanium phthalocyanine has no peak at 26.2°.

[0047] The CuKα characteristic X-ray diffraction spectrum can be measured, for example, by the following method. First, a sample (oxytitanium phthalocyanine) is placed in a sample holder of an X-ray diffraction apparatus ("RINT (Japanese registered trademark) 1100" manufactured by Rigaku Corporation) and an X-ray tube of Cu, a tube voltage of 40 kV, a tube current of 30 mA, and a CuKα characteristic X-ray wavelength of 1.1447 W is used. The X-ray diffraction spectrum is measured under the following conditions. The measurement range (2θ) is, for example, 3° to 40° (start angle 3°, stop angle 40°), and the scanning speed is, for example, 10° / min. The main peak is determined based on the obtained X-ray diffraction spectrum, and the Bragg angle of the main peak is read.

[0048] The content of the charge generating agent is preferably 0.1 parts by mass or more and 50 parts by mass or less, and more preferably 0.5 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the binder resin.

[0049] (Binder resin)

[0050] The binder resin contains a polyarylate resin. The polyarylate resin has repeating units represented by formulas (1), (2), (3) and (4). The content of the repeating unit represented by formula (3) is greater than 0% and less than 20% relative to the total number of the repeating units represented by formulas (1) and (3).

[0051]

[0052] In formula (1), R 1 and R 2 Each independently represents a hydrogen atom or a methyl group, and X represents a divalent group represented by formula (X1) or (X2). In formula (2), W represents a divalent group represented by formula (W1) or (W2).

[0053]

[0054] In formula (X1), t represents an integer of 1 to 3, and * represents a bonding bond. 3 and R 4 represents a hydrogen atom or a C1-C4 alkyl group, R 3 and R 4 denotes different groups, and * denotes a bond.

[0055]

[0056] In formulae (W1) and (W2), * represents a bond.

[0057] Hereinafter, the repeating units represented by the formulae (1), (2), (3) and (4) are sometimes respectively described as "repeating units (1), (2), (3) and (4)". In addition, the content of the repeating unit (3) relative to the total number of the repeating units (1) and (3) is sometimes described as "content (3)". In addition, a polyarylate resin having repeating units (1), (2), (3) and (4) and having a content (3) of more than 0% and less than 20% is sometimes described as "polyarylate resin (PA)".

[0058] The polyarylate resin (PA) has the essential repeating units (1), (2), (3) and (4). Due to the presence of such repeating units, the polyarylate resin (PA) has excellent solubility in a solvent and can improve the wear resistance of the photoreceptor when contained in the photosensitive layer. In addition, the charging stability of the photoreceptor can be improved, and transfer memory can be suppressed.

[0059] The content (3) refers to the percentage of the number N3 of repeating units (3) relative to the total number N1 of repeating units (1) and the number N3 of repeating units (3) possessed by the polyarylate resin (PA) (i.e., 100×N3 / (N1+N3)). By making the content (3) less than 20%, the solubility of the polyarylate resin (PA) in the solvent is improved. By making the content (3) greater than 0%, that is, the content (3) is not 0%, when the polyarylate resin (PA) is contained in the photosensitive layer, the wear resistance of the photoreceptor is improved. In addition, the charging stability of the photoreceptor is improved, and the transfer memory is suppressed. The content (3) is preferably 1% or more, and more preferably 5% or more. In addition, the content (3) is preferably 19% or less, and more preferably 10% or less.

[0060] 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 recorded as "content (4)". Content (4) refers to the percentage of the number N4 of repeating units (4) relative to the total number N2 of repeating units (2) and the number N4 of repeating units (4) possessed by the polyarylate resin (PA) (i.e., 100×N4 / (N2+N4)). The content (4) is greater than 0%, that is, the content (4) is not 0%, and therefore the polyarylate resin (PA) has a repeating unit (4). By having the repeating unit (4), the solubility of the polyarylate resin (PA) in the solvent is improved, and when the polyarylate resin (PA) is contained in the photosensitive layer, the wear resistance of the photoreceptor is improved. In addition, the charging stability of the photoreceptor is improved, and the transfer memory is suppressed. On the other hand, the content (4) is less than 100%, that is, the content (4) is not 100%, so the polyarylate resin (PA) has a repeating unit (2). By having the repeating unit (2), when the polyarylate resin (PA) is contained in the photosensitive layer, the wear resistance of the photoreceptor is improved. The content (4) is preferably 1% or more, more preferably 10% or more, and further preferably 35% or more. In addition, the content (4) is preferably 99% or less, more preferably 80% or less, and further preferably 65% ​​or less.

[0061] The proton nuclear magnetic resonance spectrometer was used to measure the 1 H-NMR spectrum, according to the obtained 1 The contents (3) and (4) can be calculated from the ratio of the characteristic peaks of the repeating units in the H-NMR spectrum.

[0062] In formula (1), R 1 and R 2 Preferably it represents a methyl group.

[0063] In formula (X1), t preferably represents 2.

[0064] In formula (X2), preferably: R 3 represents a hydrogen atom and R 4 represents methyl, ethyl or C3 alkyl; R 3 represents methyl and R 4 represents ethyl or C3 alkyl; or R 3 represents ethyl and R 4 represents a C3 alkyl group. More preferably, R 3 represents methyl and R 4 It represents ethyl.

[0065] The bond represented by * in formula (X1) and (X2) is bonded to the carbon atom to which X in formula (1) is bonded. The bond represented by * in formula (W1) and (W2) is bonded to the carbon atom to which W in formula (2) is bonded.

[0066] Examples of the repeating unit (1) include repeating units represented by formulae (1-1), (1-2) and (1-3) (hereinafter, sometimes referred to as repeating units (1-1), (1-2) and (1-3), respectively).

[0067]

[0068] The repeating unit (2) is a repeating unit represented by the formula (2-1) or (2-2) (hereinafter, sometimes referred to as repeating units (2-1) and (2-2) respectively).

[0069]

[0070] In one embodiment, it is preferred that: in formula (1), R 1 and R 2 represents a methyl group, and X is a divalent group represented by the formula (X1). The repeating unit (1) is more preferably the repeating unit (1-1). It is further preferred that: the repeating unit (1) is the repeating unit (1-1) and the repeating unit (2) is the repeating unit (2-1); or the repeating unit (1) is the repeating unit (1-1) and the repeating unit (2) is the repeating unit (2-2).

[0071] In another embodiment, it is preferred that: in formula (1), R 1 and R 2represents a hydrogen atom, and X is a divalent group represented by formula (X2). The repeating unit (1) is more preferably a repeating unit (1-2). It is further preferred that: the repeating unit (1) is a repeating unit (1-2) and the repeating unit (2) is a repeating unit (2-1); or the repeating unit (1) is a repeating unit (1-2) and the repeating unit (2) is a repeating unit (2-2). By allowing the polyarylate resin (PA) described in another embodiment to be contained in the photosensitive layer, the wear resistance of the photoreceptor is further improved. In addition, the charging stability of the photoreceptor is further improved, and the transfer memory is further suppressed.

[0072] The polyarylate resin (PA) may also have an end group. Examples of the end groups possessed by the polyarylate resin (PA) include the end groups represented by formulas (T-1) and (T-2). The end group represented by formula (T-1) is preferably an end group represented by formula (T-DMP) (hereinafter, sometimes described as end group (T-DMP)). The end group represented by formula (T-2) is preferably an end group represented by formula (T-PFH) (hereinafter, sometimes described as end group (T-PFH)).

[0073]

[0074] In formula (T-1), R 11 represents a C1-C6 alkyl group or a halogen atom, and p represents an integer of 0 to 5. 11 Preferably, it represents a C1-C6 alkyl group, more preferably a C1-C3 alkyl group, and still more preferably a methyl group. p preferably represents an integer of 1 to 3, and more preferably 2.

[0075] In formula (T-2), R 12 R represents a C1-C6 alkylidene group, and Rf represents a C1-C10 perfluoroalkyl group. 12 Preferably, it represents a C1-C3 alkylidene group, and more preferably, it represents a methylene group. Preferably, Rf represents a C3-C10 perfluoroalkyl group, more preferably, it represents a C5-C7 perfluoroalkyl group, and further preferably, it represents a C6 perfluoroalkyl group.

[0076] The * in formula (T-1), (T-2), (T-DMP) and (T-PFH) represents a bond. The bond represented by the * in formula (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 polyarylate resin (PA) and derived from a dicarboxylic acid.

[0077] Preferred examples of the polyarylate resin (PA) are the polyarylate resins (PA-1) to (PA-4) in Table 1. The polyarylate resins (PA-1) to (PA-4) respectively have repeating units (1) to (4) in Table 1. In Table 1 and Table 2 described later, the units (1) to (4) respectively represent repeating units (1) to (4).

[0078]

Table 1

[0079] Polyarylate resin Unit(1) Unit(2) Unit(3) Unit(4) PA-1 1-1 2-1 3 4 PA-2 1-2 2-1 3 4 PA-3 1-1 2-2 3 4 PA-4 1-2 2-2 3 4

[0080] Further preferred examples of the polyarylate resin (PA) are the polyarylate resins (PA-a) to (PA-h) shown in Table 2. The polyarylate resins (PA-a) to (PA-h) have the repeating units (1) to (4) shown in Table 2 and the terminal groups shown in Table 2, respectively.

[0081]

Table 2

[0082] Polyarylate resin Unit(1) Unit(2) Unit(3) Unit(4) Terminal group PA-a 1-1 2-1 3 4 T-DMP PA-b 1-2 2-1 3 4 T-DMP PA-c 1-1 2-2 3 4 T-DMP PA-d 1-2 2-2 3 4 T-DMP PA-e 1-1 2-1 3 4 T-PFH PA-f 1-2 2-1 3 4 T-PFH PA-g 1-1 2-2 3 4 T-PFH PA-h 1-2 2-2 3 4 T-PFH

[0083] In the polyarylate resin (PA), the repeating unit derived from bisphenol (more specifically, the repeating unit (1) or (3)) and the repeating unit derived from dicarboxylic acid (more specifically, the repeating unit (2) or (4)) are adjacent to each other and bonded to each other. That is, the repeating unit (1) can be combined with the repeating unit (2) or with the repeating unit (4). Furthermore, the repeating unit (3) can be combined with the repeating unit (2) or with the repeating unit (4). The repeating units derived from bisphenol and the repeating units derived from dicarboxylic acid have approximately the same number, satisfying the calculation formula "the number of repeating units derived from dicarboxylic acid = the number of repeating units derived from bisphenol + 1". The polyarylate resin (PA) can be, for example, a random copolymer, an alternating copolymer, a periodic copolymer or a block copolymer.

[0084] In the polyarylate resin (PA), the repeating unit (1) may contain only one type of repeating unit (1), or may contain two or more types (e.g., two types) of repeating units (1). In the polyarylate resin (PA), the repeating unit (2) may contain only one type of repeating unit (2), or may contain two types of repeating units (2).

[0085] The polyarylate resin (PA) may further have repeating units other than repeating units (1) to (4). However, in order to improve solubility in solvents, improve abrasion resistance of the photosensitive body when the photosensitive layer contains the polyarylate resin (PA), improve charging stability, and suppress transfer memory, the content of repeating units (1) to (4) relative to the total number of repeating units in the polyarylate resin (PA) is preferably 90% or more, more preferably 95% or more, further preferably 99% or more, and particularly preferably 100%. That is, the polyarylate resin (PA) particularly preferably has only repeating units (1) to (4) as repeating units.

[0086] In order to improve solubility in a solvent, the content of the repeating unit (3) is preferably 20% or less, more preferably less than 20%, based on the total number of repeating units derived from bisphenol in the polyarylate resin (PA).

[0087] The viscosity average molecular weight of the polyarylate resin (PA) is preferably 10,000 or more, more preferably 30,000 or more, further preferably 50,000 or more, and particularly preferably 55,000 or more. When the viscosity average molecular weight of the polyarylate resin (PA) is 10,000 or more, when it is contained in the photosensitive layer of the photoreceptor, the wear resistance of the photoreceptor is improved. On the other hand, the viscosity average molecular weight of the polyarylate resin (PA) is preferably 80,000 or less, more preferably 70,000 or less, and further preferably 60,000 or less. When the viscosity average molecular weight of the polyarylate resin (PA) is 80,000 or less, the solubility of the polyarylate resin (PA) in the solvent is improved. The viscosity average molecular weight of the polyarylate resin (PA) is measured in accordance with JIS (Japanese Industrial Standards) K7252-1:2016.

[0088] Next, the method for producing the polyarylate resin (PA) is described. The method for producing the polyarylate resin (PA) is, for example, a method of polycondensing bisphenol (used to form repeating units derived from bisphenol) and dicarboxylic acid (used to form repeating units derived from dicarboxylic acid). The polycondensation can be performed by a well-known synthesis method (for example, solution polymerization, melt polymerization, or interfacial polymerization).

[0089] Examples of bisphenols (used to form repeating units derived from bisphenols) include compounds represented by formulas (BP-1) and (BP-3) (hereinafter, sometimes referred to as compounds (BP-1) and (BP-3) respectively). Examples of dicarboxylic acids (used to form repeating units derived from dicarboxylic acids) include compounds represented by 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 formula (1) 1 , R2 and X have the same meanings. W in formula (DC-2) has the same meanings as W in formula (2).

[0090]

[0091] In the production of polyarylate resin (PA), the percentage of the amount (unit: mole) of compound (BP-3) relative to the total amount (unit: mole) of compounds (BP-1) and (BP-3) corresponds to content (3). In addition, the percentage of the amount (unit: mole) of compound (DC-4) relative to the total amount (unit: mole) of compounds (DC-2) and (DC-4) corresponds to content (4).

[0092] Bisphenols may also be used in the form of derivatized aromatic diacetates. Dicarboxylic acids may also be used as derivatives. Examples of dicarboxylic acid derivatives include dicarboxylic acid dichlorides, dicarboxylic acid dimethyl esters, dicarboxylic acid diethyl esters, and dicarboxylic acid anhydrides. Dicarboxylic acid dichlorides are compounds in which two "-C(=O)-OH" groups of dicarboxylic acids are each replaced by a "-C(=O)-Cl" group.

[0093] In the polycondensation of bisphenol and dicarboxylic acid, a terminal terminator may be added. Examples of the terminal terminator include 2,6-dimethylphenol and 1H,1H-perfluoro-1-heptanol. By using 2,6-dimethylphenol as the terminal terminator, a terminal group (T-DMP) can be formed. By using 1H,1H-perfluoro-1-heptanol as the terminal terminator, a terminal group (T-PFH) can be formed.

[0094] In the polycondensation of bisphenol and dicarboxylic acid, one or both of a base and a catalyst may be added. An example of the base is sodium hydroxide. An example of the catalyst is benzyltributylammonium chloride, ammonium chloride, ammonium bromide, quaternary ammonium salts, triethylamine, and trimethylamine.

[0095] In the photosensitive layer, the binder resin may contain only one polyarylate resin (PA) or may contain two or more polyarylate resins (PA). In addition, in the photosensitive layer, the binder resin may contain only polyarylate resin (PA) or may further contain a binder resin other than polyarylate resin (PA) (hereinafter, sometimes described as other binder resin). Other binder resins include, for example, thermoplastic resins (more specifically, polyarylate resins other than polyarylate resins (PA), polycarbonate resins, styrene 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 cross-linking thermosetting resins) and photocurable resins (more specifically, epoxy-acrylic resins and polyurethane-acrylic copolymers).

[0096] (Electron Transport Agent)

[0097] The photosensitive layer contains two electron transport agents, namely, a first electron transport agent and a second electron transport agent. By making the photosensitive layer contain the first electron transport agent and the second electron transport agent in addition to the polyarylate resin (PA), the charging stability of the photoreceptor can be improved and the transfer memory can be suppressed. The reason is presumed to be as follows.

[0098] The absolute value of the reduction potential of the first electron transport agent (for example, approximately -0.7 V to -0.6 V) is smaller than the absolute value of the reduction potential of the second electron transport agent (for example, approximately -0.9 V to -0.8 V).

[0099] The smaller the absolute value of the reduction potential of the electron transport agent, the higher the electron-attracting property of the electron transport agent, and the easier it is for the electron transport agent to absorb electrons from the charge generating agent. In the first embodiment, the first electron transport agent with a small absolute value of the reduction potential absorbs electrons from the charge generating agent well, and the amount of electrons remaining in the charge generating agent is reduced. As a result, the charging stability of the photoreceptor is improved.

[0100] In addition, the greater the absolute value of the reduction potential of the electron transport agent, the higher the electron transport speed of the electron transport agent. As the electron transport speed increases, the amount of electrons remaining in the photosensitive layer decreases, and the transfer memory of the photosensitive body is suppressed. In the first embodiment, the second electron transport agent with a large absolute value of the reduction potential quickly transports electrons, and the amount of electrons remaining in the photosensitive layer decreases. As a result, the transfer memory of the photosensitive body is suppressed.

[0101] The first electron transport agent contains a compound represented by formula (A15) or (A16) (hereinafter, sometimes referred to as first electron transport agents (A15) and (A16) respectively). The second electron transport agent contains a compound represented by formula (B10), (B11), (B12), (B13) or (B14) (hereinafter, sometimes referred to as second electron transport agents (B10), (B11), (B12), (B13) and (B14) respectively).

[0102]

[0103] Q in formula (A15) 51 , Q 52 , Q 53 , Q 54 , Q 55 and Q 56 , Q in formula (A16) 61 and Q 62 , Q in formula (B10) 1 and Q 2 , Q in formula (B11) 11 , Q 12 and Q 13 , Q in formula (B12) 21 , Q 22 , Q 23 and Q 24 , Q in formula (B13) 31 and Q 32 And Q in formula (B14) 41 , Q 42 , Q 43 and Q 44 Each independently represents a hydrogen atom, a halogen atom, a cyano group, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C1-C6 alkoxy group, an unsubstituted C6-C14 aryl group, or a C6-C14 aryl group substituted with at least one substituent selected from the group consisting of a C1-C6 alkyl group and a halogen atom. 1 and Y 2 Each independently represents an oxygen atom or a sulfur atom.

[0104] Q in formula (A15) 51 ~Q56 , Q in formula (A16) 61 and Q 62 , Q in formula (B10) 1 and Q 2 , Q in formula (B11) 11 ~Q 13 , Q in formula (B12) 21 ~Q 24 , Q in formula (B13) 31 and Q 32 And Q in formula (B14) 41 ~Q 44 Each of them independently represents preferably a hydrogen atom, a C1-C6 alkyl group, an unsubstituted C6-C14 aryl group, or a C6-C14 aryl group substituted with at least one substituent selected from the group consisting of a C1-C6 alkyl group and a halogen atom. 1 and Y 2 Preferably, it represents an oxygen atom.

[0105] Q in formula (A15) 51 ~Q 56 , Q in formula (A16) 61 and Q 62 , Q in formula (B10) 1 and Q 2 , Q in formula (B11) 11 ~Q 13 , Q in formula (B12) 21 ~Q 24 , Q in formula (B13) 31 and Q 32 And Q in formula (B14) 41 ~Q 44 When it represents a C1-C6 alkyl group, it is preferably a C1-C5 alkyl group, preferably a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group, and particularly preferably a methyl group, an isopropyl group, a tert-butyl group or a 1,1-dimethylpropyl group.

[0106] Q in formula (A15) 51 ~Q 56 , Q in formula (A16) 61 and Q 62 , Q in formula (B10) 1 and Q 2 , Q in formula (B11) 11 ~Q 13 , Q in formula (B12) 21 ~Q 24 , Q in formula (B13) 31 and Q 32 And Q in formula (B14) 41 ~Q44 When representing a C6-C14 aryl group, it is preferably a C6-C10 aryl group, and more preferably a phenyl group. The C6-C14 aryl group may be: an unsubstituted C6-C14 aryl group or a C6-C14 aryl group substituted by at least one substituent selected from the group consisting of a C1-C6 alkyl group and a halogen atom. The C1-C6 alkyl group as a substituent is preferably a C1-C3 alkyl group, and more preferably a methyl group or an ethyl group. The halogen atom as a substituent is preferably a fluorine atom, a chlorine atom or a bromine atom, and particularly preferably a chlorine atom. In the case where the C6-C14 aryl group has a substituent, the number of substituents is preferably 1 or more and 5 or less, and more preferably 1 or 2. The C6-C14 aryl group substituted by at least one substituent selected from the group consisting of a C1-C6 alkyl group and a halogen atom is preferably a chlorophenyl group, a dichlorophenyl group or an ethylmethylphenyl group, and more preferably a 4-chlorophenyl group, a 2,5-dichlorophenyl group or a 2-ethyl-6-methylphenyl group.

[0107] Preferred examples of the first electron transport agent (A15) include compounds represented by formula (E-2) and (E-3). Preferred examples of the first electron transport agent (A16) include compounds represented by formula (E-1). Hereinafter, compounds represented by formulas (E-1) to (E-3) are sometimes referred to as electron transport agents (E-1) to (E-3), respectively.

[0108]

[0109] Preferred examples of the second electron transport agent (B10) include: compounds represented by formula (E-4). Preferred examples of the second electron transport agent (B11) include: compounds represented by formula (E-5). Preferred examples of the second electron transport agent (B12) include: compounds represented by formula (E-7). Preferred examples of the second electron transport agent (B13) include: compounds represented by formula (E-6). Preferred examples of the second electron transport agent (B14) include: compounds represented by formula (E-8). Hereinafter, compounds represented by formulas (E-4) to (E-8) are sometimes respectively described as electron transport agents (E-4) to (E-8).

[0110]

[0111] The first electron transport agent in the photosensitive layer may contain only one first electron transport agent or two or more first electron transport agents. The second electron transport agent in the photosensitive layer may contain only one second electron transport agent or two or more second electron transport agents.

[0112] The ratio M1 / M2 of the mass of the first electron transport agent M1 to the mass of the second electron transport agent M2 is preferably 0.10 to 10.00, more preferably 0.25 to 4.00, and even more preferably 0.50 to 3.00.

[0113] The content of the electron transport agent (the total content of the first electron transport agent and the second electron transport agent) is preferably 5 parts by mass to 150 parts by mass, more preferably 10 parts by mass to 100 parts by mass, and further preferably 30 parts by mass to 70 parts by mass, relative to 100 parts by mass of the binder resin.

[0114] The photosensitive layer may further contain an electron transport agent other than the first electron transport agent and the second electron transport agent (hereinafter sometimes described as other electron transport agents). Examples of other electron transport agents include: quinone compounds, imide compounds, hydrazone compounds, malononitrile compounds, thiopyran compounds, trinitrothioxanthone compounds, 3,4,5,7-tetranitro-9-fluorenone compounds, dinitroanthracene compounds, dinitroacridine compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride and dibromomaleic anhydride. Examples of quinone compounds include: diphenoquinone compounds, azoquinone compounds, anthraquinone compounds, naphthoquinone compounds, nitroanthraquinone compounds and dinitroanthraquinone compounds.

[0115] (Hole Transport Agent)

[0116] The hole transport agent is, for example, a triphenylamine derivative, a diamine derivative (for example, a N,N,N',N'-tetraphenylbenzidine derivative, a N,N,N',N'-tetraphenylphenylenediamine derivative, a N,N,N',N'-tetraphenylnaphthalenediamine derivative, a N,N,N',N'-tetraphenylphenanthrylene diamine derivative, diamine) derivatives and di(aminophenylvinyl)benzene derivatives), oxadiazole compounds (for example, 2,5-bis(4-methylaminophenyl)-1,3,4-oxadiazole), styrene compounds (for example, 9-(4-diethylaminostyryl)anthracene), carbazole compounds (for example, polyvinylcarbazole), organic polysilane compounds, pyrazoline compounds (for example, 1-phenyl-3-(p-dimethylaminophenyl)pyrazoline), hydrazone compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds and triazole compounds.

[0117] Preferred examples of the hole transport agent include compounds represented by formulae (21), (22) and (23) (hereinafter, sometimes referred to as hole transport agents (21), (22) and (23), respectively).

[0118]

[0119] In formula (21), R 21 , R 22 and R 23 Each independently represents a C1-C6 alkyl group. 24 , R 25 and R 26 b1, b2 and b3 are each independently a hydrogen atom or a C1-C6 alkyl group. b1, b2 and b3 are each independently a 0 or 1.

[0120] In formula (21), R 21 , R 22 and R 23 Each of them is independently preferably a C1-C3 alkyl group, and more preferably a methyl group. 21 , R 22 and R 23 Preferably, it is bonded to the meta position of the phenyl group relative to the vinyl group or the butadienyl group. 24 , R 25 and R 26 Preferably, all of b1, b2 and b3 represent 0 or 1.

[0121] In formula (22), R 31 , R 32 and R 33 Each independently represents a C1-C6 alkyl group. 34 represents a C1-C6 alkyl group or a hydrogen atom. d1, d2 and d3 each independently represent an integer of 0 or more and 5 or less.

[0122] In formula (22), when d1 represents an integer of 2 to 5, a plurality of R 31 When d2 represents an integer from 2 to 5, a plurality of R 32 When d3 represents an integer from 2 to 5, a plurality of R 33 The same as or different from each other.

[0123] In formula (22), R 34 Preferably, d1, d2 and d3 are all 0.

[0124] In formula (23), R 50 and R 51 Each independently represents a C1-C6 alkyl group, a C1-C6 alkoxy group or a phenyl group.52 , R 53 , R 54 , R 55 , R 56 , R 57 and R 58 Each independently represents a hydrogen atom, a C1-C6 alkyl group, a C1-C6 alkoxy group, an unsubstituted phenyl group, or a phenyl group substituted with a C1-C6 alkyl group. f1 and f2 each independently represent an integer from 0 to 2. f3 and f4 each independently represent an integer from 0 to 5.

[0125] In formula (23), when f3 represents an integer of 2 to 5, a plurality of R 50 When f4 represents an integer from 2 to 5, a plurality of R 51 The same as or different from each other.

[0126] In formula (23), R 50 and R 51 Each independently represents a C1-C6 alkyl group. 52 and R 53 Each preferably represents a hydrogen atom, an unsubstituted phenyl group, or a phenyl group having a C1-C6 alkyl substituent. 54 ~R 58 Each independently represents a hydrogen atom, a C1-C6 alkyl group or a C1-C6 alkoxy group. f1 and f2 preferably both represent 0, both represent 1 or both represent 2. f3 and f4 preferably both represent 0 or 1.

[0127] R 50 and R 51 When it represents a C1-C6 alkyl group, it is preferably a C1-C3 alkyl group, and more preferably a methyl group. 52 and R 53 When it represents an unsubstituted phenyl group or a phenyl group having a C1-C6 alkyl substituent, it is preferably an unsubstituted phenyl group or a phenyl group having a C1-C3 alkyl substituent. The phenyl group having a C1-C3 alkyl substituent is preferably a methylphenyl group, and more preferably a 4-methylphenyl group. 54 ~R 58 When it represents a C1-C6 alkyl group, it is preferably a C1-C4 alkyl group, and preferably represents a methyl group, an ethyl group or an n-butyl group. 54 ~R 58 When it represents a C1-C6 alkoxy group, it is preferably a C1-C3 alkoxy group, and more preferably an ethoxy group.

[0128] Further preferred examples of hole transport agents include compounds represented by formula (H-1), (H-2), (H-3), (H-4), (H-5), (H-6), (H-7) or (H-8) (hereinafter sometimes respectively described as hole transport agents (H-1), (H-2), (H-3), (H-4), (H-5), (H-6), (H-7) and (H-8)).

[0129]

[0130]

[0131]

[0132] The content of the hole transport agent is preferably 10 to 200 parts by mass, more preferably 30 to 120 parts by mass, and further preferably 50 to 90 parts by mass, relative to 100 parts by mass of the binder resin. In addition, the photosensitive layer may contain only one hole transport agent or two or more hole transport agents.

[0133] (additive)

[0134] Examples of the additives include ultraviolet absorbers, antioxidants, radical scavengers, singlet quenchers, softeners, surface modifiers, extenders, thickeners, waxes, donors, surfactants, plasticizers, sensitizers, and leveling agents.

[0135] (Combination of materials)

[0136] In order to form a photosensitive layer well, improve the charging stability of the photoreceptor and inhibit transfer memory, it is preferred that: the binding resin is a polyarylate resin (PA-1), (PA-2), (PA-3), (PA-4), (PA-a), (PA-b), (PA-c), (PA-d), (PA-e), (PA-f), (PA-g), (PA-h), A, B, C, D, E, F, G, H, I or J, the first electron transport agent is an electron transport agent (E-1), (E-2) or (E-3), and the second electron transport agent is an electron transport agent (E-4), (E-5), (E-6), (E-7) or (E-8). Based on the same consideration, it is more preferred that the binder resin is a polyarylate resin (PA-1), (PA-2), (PA-3), (PA-4), (PA-a), (PA-b), (PA-c), (PA-d), (PA-e), (PA-f), (PA-g), (PA-h), A, B, C, D, E, F, G, H, I or J, the first electron transport agent is an electron transport agent (E-1), (E-2) or (E-3), the second electron transport agent is an electron transport agent (E-4), (E-5), (E-6), (E-7) or (E-8), and the hole transport agent is a hole transport agent (H-1), (H-2), (H-3), (H-4), (H-5), (H-6), (H-7) or (H-8). In addition, the polyarylate resins A to J will be described in detail in the examples.

[0137] In order to particularly improve the charging stability of the photoreceptor, it is preferred that the first electron transport agent and the second electron transport agent are electron transport agents (E-1) and (E-4) or electron transport agents (E-2) and (E-5). Based on the same consideration, it is more preferred that the first electron transport agent and the second electron transport agent are electron transport agents (E-1) and (E-4) or electron transport agents (E-2) and (E-5), and the binder resin is polyarylate resin (PA-1), (PA-3), (PA-a), (PA-c), (PA-e), (PA-g), A, C, F or J. Based on the same considerations, it is further preferred that: the first electron transport agent and the second electron transport agent are electron transport agents (E-1) and (E-4) or electron transport agents (E-2) and (E-5), the binding resin is polyarylate resin (PA-1), (PA-3), (PA-a), (PA-c), (PA-e), (PA-g), A, C, F or J, and the hole transport agent is hole transport agent (H-1), (H-6) or (H-7).

[0138] In order to particularly improve the sensitivity characteristics of the photoreceptor, it is preferred that the first electron transport agent and the second electron transport agent are electron transport agents (E-1) and (E-4), electron transport agents (E-1) and (E-5), electron transport agents (E-1) and (E-8), electron transport agents (E-2) and (E-5), electron transport agents (E-3) and (E-4), or electron transport agents (E-3) and (E-5). Based on the same consideration, it is more preferred that the first electron transport agent and the second electron transport agent are electron transport agents (E-1) and (E-4), electron transport agents (E-1) and (E-5), electron transport agents (E-1) and (E-8), electron transport agents (E-2) and (E-5), electron transport agents (E-3) and (E-4), or electron transport agents (E-3) and (E-5), and the binder resin is polyarylate resin (PA-1), (PA-a), (PA-e), C, D, G or H. Based on the same considerations, it is further preferred that: the first electron transport agent and the second electron transport agent are electron transport agents (E-1) and (E-4), electron transport agents (E-1) and (E-5), electron transport agents (E-1) and (E-8), electron transport agents (E-2) and (E-5), electron transport agents (E-3) and (E-4) or electron transport agents (E-3) and (E-5), the binding resin is polyarylate resin (PA-1), (PA-a), (PA-e), C, D, G or H, and the hole transport agent is hole transport agent (H-1), (H-2) or (H-4).

[0139] In order to particularly suppress the transfer memory of the photoreceptor, it is preferred that the first electron transport agent and the second electron transport agent are electron transport agents (E-1) and (E-4), electron transport agents (E-1) and (E-7), electron transport agents (E-2) and (E-4), electron transport agents (E-2) and (E-5), electron transport agents (E-2) and (E-6), or electron transport agents (E-2) and (E-7). Based on the same considerations, it is more preferred that the first electron transporter and the second electron transporter are electron transporters (E-1) and (E-4), electron transporters (E-1) and (E-7), electron transporters (E-2) and (E-4), electron transporters (E-2) and (E-5), electron transporters (E-2) and (E-6) or electron transporters (E-2) and (E-7), and the binding resin is polyarylate resin (PA-1), (PA-2), (PA-3), (PA-a), (PA-b), (PA-c), (PA-e), (PA-f), (PA-g), A, D, E, F or J. Based on the same considerations, it is further preferred that: the first electron transport agent and the second electron transport agent are electron transport agents (E-1) and (E-4), electron transport agents (E-1) and (E-7), electron transport agents (E-2) and (E-4), electron transport agents (E-2) and (E-5), electron transport agents (E-2) and (E-6) or electron transport agents (E-2) and (E-7), the binder resin is polyarylate resin (PA-1), (PA-2), (PA-3), (PA-a), (PA-b), (PA-c), (PA-e), (PA-f), (PA-g), A, D, E, F or J, and the hole transport agent is hole transport agent (H-3), (H-4) or (H-7).

[0140] (Conductive substrate)

[0141] The conductive substrate is not particularly limited as long as it can be used as a conductive substrate for a photoreceptor. The conductive substrate can be any substrate as long as at least its surface portion is formed of a conductive material. An example of a conductive substrate is a conductive substrate composed of a conductive material. Another example of a conductive substrate 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 an aluminum alloy is preferred from the viewpoint of good charge transfer from the photosensitive layer to the conductive substrate.

[0142] The shape of the conductive substrate is appropriately selected according to the structure of the image forming apparatus. The shape of the conductive substrate is, for example, a sheet shape or a drum shape. Also, the thickness of the conductive substrate is appropriately selected according to the shape of the conductive substrate.

[0143] (Middle layer)

[0144] The intermediate layer (undercoat layer) contains, for example, inorganic particles and a resin used in the intermediate layer (intermediate layer resin). It is believed that the presence of the intermediate layer can maintain an insulating state to such an extent that leakage current can be suppressed, while allowing the current generated when the photoreceptor is exposed to flow smoothly, thereby suppressing an increase in resistance.

[0145] Examples of the inorganic particles include particles of metals (eg, aluminum, iron, and copper), particles of metal oxides (eg, titanium dioxide, aluminum oxide, zirconium oxide, tin oxide, and zinc oxide), and particles of non-metallic oxides (eg, silicon dioxide).

[0146] Examples of the intermediate layer resin are the same as the examples of the other binding resins mentioned above. In order to form the intermediate layer and the photosensitive layer well, the intermediate layer resin is preferably different from the binding resin contained in the photosensitive layer. The intermediate layer may also contain additives. Examples of the additives contained in the intermediate layer are the same as the examples of the additives contained in the photosensitive layer.

[0147] (Method for producing photoreceptor)

[0148] Next, an example of a method for manufacturing a photoreceptor is described. The method for manufacturing a photoreceptor includes a photosensitive layer forming step. In the photosensitive layer forming step, a coating liquid for forming a photosensitive layer (hereinafter, sometimes described as a photosensitive layer coating liquid) is prepared. The photosensitive layer coating liquid is applied to a conductive substrate. Then, at least a portion of the solvent contained in the applied photosensitive layer coating liquid is removed, thereby forming a photosensitive layer. The photosensitive layer coating liquid contains, for example, a charge generating agent, a hole transporting agent, a first electron transporting agent, a second electron transporting agent, a binding resin, a solvent, and additives added as needed. The photosensitive layer coating liquid is prepared by dissolving or dispersing the charge generating agent, the hole transporting agent, the first electron transporting agent, the second electron transporting agent, the binding resin, and additives added as needed in a solvent.

[0149] The solvent contained in the photosensitive layer coating liquid is not particularly limited as long as it can dissolve or disperse the components contained in the photosensitive layer coating liquid. Examples of the solvent include alcohols (more specifically, methanol, ethanol, isopropanol, butanol, etc.), aliphatic hydrocarbons (more specifically, n-hexane, octane, cyclohexane, etc.), aromatic hydrocarbons (more specifically, benzene, toluene, xylene, etc.), halogenated hydrocarbons (more specifically, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, etc.), ethers (more specifically, dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, etc.), ketones (more specifically, acetone, methyl ethyl ketone, cyclohexanone, etc.), esters (more specifically, ethyl acetate, methyl acetate, etc.), dimethylformaldehyde, dimethylformamide, and dimethyl sulfoxide.

[0150] The photosensitive layer coating solution is prepared by mixing and dispersing the components in a solvent. For example, a bead mill, a roll mill, a ball mill, an attritor, a paint shaker, a rod-shaped sonic oscillator, or an ultrasonic disperser can be used for the mixing or dispersing operation.

[0151] The method of coating with the photosensitive layer coating liquid is not particularly limited as long as it can uniformly coat the photosensitive layer coating liquid. Examples of the coating method include dip coating, spray coating, spin coating, and bar coating.

[0152] The method of removing at least a part of the solvent contained in the photosensitive layer coating liquid is, for example, heating, reducing pressure, or a combination of heating and reducing pressure. More specifically, a method of heat treatment (hot air drying) using a high temperature dryer or a reduced pressure dryer can be cited. The temperature of the heat treatment is, for example, 40° C. to 150° C. The time of the heat treatment is, for example, 3 minutes to 120 minutes.

[0153] The method for producing a photoreceptor may further include a step of forming an intermediate layer as necessary. A well-known method can be selected for the step of forming the intermediate layer.

[0154] <Second Embodiment: Image Forming Apparatus>

[0155] Next, refer to Figure 4 , an image forming apparatus 100 according to a second embodiment of the present invention will be described. Figure 4 This is an example of the structure of the image forming apparatus 100. The image forming apparatus 100 is, for example, a tandem color printer.

[0156] like Figure 4 As shown, the image forming apparatus 100 includes a control unit 10 , an operation unit 20 , a paper feeding unit 30 , a conveying unit 40 , a toner replenishing unit 50 , an image forming unit 60 , a transfer device 70 , a fixing device 80 , and a discharge unit 90 .

[0157] The control unit 10 controls the operation of each component of the image forming apparatus 100. The control unit 10 includes a processor (not shown) and a storage unit (not shown). The processor includes, for example, a CPU (Central Processing Unit). The storage unit includes a memory such as a semiconductor memory, and may also include an HDD (Hard Disk Drive). The processor controls the operation of the image forming apparatus 100 by executing a control program. The storage unit stores the control program.

[0158] The operation unit 20 receives an instruction from the user. After receiving the instruction from the user, the operation unit 20 transmits a signal indicating the user's instruction to the control unit 10. As a result, the image forming apparatus 100 starts an image forming operation.

[0159] The paper feed unit 30 includes a paper feed cassette 31 and a paper feed roller group 32 . The paper feed cassette 31 can store a plurality of recording media P (eg, paper). The paper feed roller group 32 supplies the recording media P stored in the paper feed cassette 31 to the conveying unit 40 one by one.

[0160] The conveying unit 40 includes rollers and guide members. The conveying unit 40 extends from the paper feed unit 30 to the discharge unit 90. The conveying unit 40 conveys the recording medium P from the paper feed unit 30 to the discharge unit 90 via the image forming unit 60 and the fixing device 80.

[0161] The toner replenishing section 50 replenishes toner to the image forming section 60. The toner replenishing section 50 includes a first mounting section 51Y, a second mounting section 51C, a third mounting section 51M, and a fourth mounting section 51K.

[0162] The first toner container 52Y is mounted on the first mounting portion 51Y. Similarly, the second toner container 52C is mounted on the second mounting portion 51C, the third toner container 52M is mounted on the third mounting portion 51M, and the fourth toner container 52K is mounted on the fourth mounting portion 51K.

[0163] The first toner container 52Y, the second toner container 52C, the third toner container 52M, and the fourth toner container 52K each contain a toner. In the second embodiment, the first toner container 52Y contains a yellow toner. The second toner container 52C contains a cyan toner. The third toner container 52M contains a magenta toner. The fourth toner container 52K contains a black toner.

[0164] The image forming section 60 includes an exposure device 61 , a first image forming unit 62Y, a second image forming unit 62C, a third image forming unit 62M, and a fourth image forming unit 62K.

[0165] Each of the first to fourth image forming units 62Y to 62K includes a charging device 63 , a developing device 64 , an image carrier 65 , a cleaning device 66 , and a static eliminating device 67 .

[0166] The first to fourth image forming units 62Y to 62K have the same structure except that the type of toner replenished from the toner replenishing unit 50 is different. Figure 4 In FIG. 1 , reference numerals of the components of the second to fourth image forming units 62C to 62K are omitted.

[0167] The image carrier 65 is the photosensitive body 1 of the first embodiment. As described in the first embodiment, the photosensitive layer is well formed in the photosensitive body 1 of the first embodiment, and the photosensitive body 1 of the first embodiment has excellent charging stability and can suppress transfer memory. Therefore, in the image forming apparatus 100 of the second embodiment, the photosensitive layer of the photosensitive body 1 as the image carrier 65 is well formed, and the charging stability can be improved and the transfer memory can be suppressed.

[0168] The charging device 63, the developing device 64, the cleaning device 66, and the static elimination device 67 are arranged along the circumferential surface of the image carrier 65. Figure 4 Rotate in the direction indicated by arrow R1 (clockwise).

[0169] The charging device 63 charges the surface (circumferential surface) of the image carrier 65. The charging device 63 charges the image carrier 65 uniformly with a predetermined polarity by discharge. In the second embodiment, the charging device 63 charges the image carrier 65 with a positive polarity. The charging device 63 is, for example, a charging roller.

[0170] The exposure device 61 exposes the surface of the charged image carrier 65. Specifically, the exposure device 61 irradiates the surface of the charged image carrier 65 with laser light. Thus, an electrostatic latent image is formed on the surface of the image carrier 65.

[0171] The toner is replenished from the toner replenishing section 50 to the developing device 64. The developing device 64 supplies the toner replenished from the toner replenishing section 50 to the surface of the image bearing member 65. As a result, the electrostatic latent image formed on the surface of the image bearing member 65 is developed into a toner image.

[0172] In the second embodiment, the developing device 64 of the first image forming unit 62Y is connected to the first toner container 52Y. Therefore, the yellow toner is replenished in the developing device 64 of the first image forming unit 62Y. As a result, a yellow toner image is formed on the surface of the image bearing body 65 of the first image forming unit 62Y.

[0173] Similarly, the developing device 64 of the second image forming unit 62C, the developing device 64 of the third image forming unit 62M, and the developing device 64 of the fourth image forming unit 62K are connected to the second toner container 52C, the third toner container 52M, and the fourth toner container 52K, respectively. Therefore, the developing device 64 of the second image forming unit 62C, the developing device 64 of the third image forming unit 62M, and the developing device 64 of the fourth image forming unit 62K are replenished with cyan toner, magenta toner, and black toner, respectively. As a result, a cyan toner image, a magenta toner image, and a black toner image are formed on the surface of the image carrier 65 of the second image forming unit 62C, the surface of the image carrier 65 of the third image forming unit 62M, and the surface of the image carrier 65 of the fourth image forming unit 62K, respectively.

[0174] The cleaning device 66 has a cleaning member 661. After the transfer by the primary transfer roller 71 described later, the cleaning device 66 recovers the toner attached to the surface of the image carrier 65. Specifically, the cleaning device 66 presses the cleaning member 661 against the surface of the image carrier 65 to recover the toner attached to the surface of the image carrier 65. The cleaning member 661 is, for example, a cleaning blade.

[0175] The static eliminating device 67 irradiates the surface of the image carrier 65 with static eliminating light to eliminate static electricity from the surface of the image carrier 65 .

[0176] The transfer device 70 transfers the toner image from the image carrier 65 to the recording medium P as a transfer target. Specifically, the transfer device 70 transfers the toner images formed on the surfaces of the image carriers 65 of the first image forming unit 62Y to the fourth image forming unit 62K to the recording medium P in an overlapping manner. In the second embodiment, the transfer device 70 transfers the toner images in an overlapping manner to the recording medium P by a secondary transfer method (intermediate transfer method). The transfer device 70 includes four primary transfer rollers 71, an intermediate transfer belt 72, a drive roller 73, a driven roller 74, and a secondary transfer roller 75.

[0177] The intermediate transfer belt 72 is an endless belt stretched and mounted on four primary transfer rollers 71, a driving roller 73, and a driven roller 74. The intermediate transfer belt 72 is driven by the rotation of the driving roller 73. Figure 4 The intermediate transfer belt 72 rotates in a counterclockwise direction. The driven roller 74 rotates according to the driving of the intermediate transfer belt 72.

[0178] The first to fourth image forming units 62Y to 62K are arranged to face the bottom surface of the intermediate transfer belt 72. In the second embodiment, the first to fourth image forming units 62Y to 62K are arranged in this order from the upstream side to the downstream side in the driving direction D of the bottom surface of the intermediate transfer belt 72.

[0179] Each primary transfer roller 71 is arranged to face each image carrier 65 with the intermediate transfer belt 72 interposed therebetween, and is pressed against each image carrier 65. Therefore, the toner images formed on the surface of each image carrier 65 are sequentially transferred to the intermediate transfer belt 72 by each primary transfer roller 71. In the second embodiment, a yellow toner image, a cyan toner image, a magenta toner image, and a black toner image are sequentially transferred to the intermediate transfer belt 72 in an overlapping manner. In the following, a toner image in which the yellow toner image, the cyan toner image, the magenta toner image, and the black toner image are superimposed is sometimes described as a "laminated toner image".

[0180] The secondary transfer roller 75 is arranged to face the driving roller 73 with the intermediate transfer belt 72 interposed therebetween. The secondary transfer roller 75 is pressed against the driving roller 73. Thus, a transfer nip is formed between the secondary transfer roller 75 and the driving roller 73. When the recording medium P passes through the transfer nip, the stacked toner image on the intermediate transfer belt 72 is transferred to the recording medium P by the secondary transfer roller 75. In the second embodiment, the yellow toner image, the cyan toner image, the magenta toner image, and the black toner image are transferred to the recording medium P in the order from the upper layer to the lower layer. The recording medium P to which the stacked toner image is transferred is sent to the fixing device 80 by the conveying unit 40.

[0181] The fixing device 80 includes a heating member 81 and a pressurizing member 82. The heating member 81 and the pressurizing member 82 are arranged to face each other, thereby forming a fixing nip. The recording medium P conveyed from the image forming unit 60 is heated at a predetermined fixing temperature and pressurized through the fixing nip. As a result, the laminated toner image is fixed on the recording medium P. The recording medium P is conveyed from the fixing device 80 to the discharge unit 90 by the conveying unit 40.

[0182] The discharge section 90 includes a discharge roller pair 91 and a discharge tray 93. The discharge roller pair 91 conveys the recording medium P to the discharge tray 93 through a discharge port 92. The discharge port 92 is formed at an upper portion of the image forming apparatus 100.

[0183] Next, refer to Figure 5 , the structure of the developing device 64 is described in detail. Figure 5 This is an example of the structure of the developing device 64. Specifically, Figure 5 denoted by the developing device 64 included in the first image forming unit 62Y. Figure 5 In the figure, the image bearing member 65 is indicated by a two-dot chain line for easy understanding. In the second embodiment, the developing device 64 adopts a two-component developing method using a two-component developer and a touchdown developing method.

[0184] As reference Figure 4 As described above, the developing container 640 of the developing device 64 is connected to the first toner container 52Y. Therefore, in the developing container 640 of the developing device 64, the yellow toner is replenished through the toner replenishing port 640h.

[0185] like Figure 5 As shown, the developing device 64 includes a developing roller 641, a magnetic roller 642, a first stirring screw 643, a second stirring screw 644, and a scraper 645 inside a developing container 640. Specifically, the developing roller 641 is arranged to face the magnetic roller 642. The magnetic roller 642 is arranged to face the second stirring screw 644. The scraper 645 is arranged to face the magnetic roller 642.

[0186] The developing container 640 is divided into a first stirring chamber 640a and a second stirring chamber 640b by a partition 640c. The partition 640c extends in the axial direction of the developing roller 641. The first stirring chamber 640a and the second stirring chamber 640b are connected outside both ends of the partition 640c in the longitudinal direction.

[0187] The first stirring chamber 640a is provided with a first stirring screw 643. The first stirring chamber 640a contains a carrier as a magnetic body. The first stirring chamber 640a is supplied with non-magnetic toner through a toner supply port 640h. Figure 5 In the example shown in FIG. 6A , yellow toner is replenished to the first stirring chamber 640 a .

[0188] The second stirring chamber 640b is provided with a second stirring screw 644. The second stirring chamber 640b contains a carrier as a magnetic body.

[0189] The yellow toner is stirred by the carrier by the first stirring screw 643 and the second stirring screw 644. As a result, a two-component developer containing the carrier and the yellow toner is formed.

[0190] The first stirring screw 643 and the second stirring screw 644 circulate and stir the two-component developer between the first stirring chamber 640a and the second stirring chamber 640b. As a result, the toner is charged to a predetermined polarity by friction with the carrier. In the second embodiment, the toner is charged to a positive polarity.

[0191] The magnetic roller 642 is composed of a non-magnetic rotating sleeve 642a and a magnet 642b. The magnet 642b is configured to be fixed inside the rotating sleeve 642a. The magnet 642b has a plurality of magnetic poles. The two-component developer is attracted to the magnetic roller 642 by the magnetic force of the magnet 642b. As a result, a magnetic brush is formed on the surface of the magnetic roller 642.

[0192] In the second embodiment, the magnetic roller 642 is arranged along Figure 5 The magnetic roller 642 rotates in the direction indicated by the arrow R3 (counterclockwise). The magnetic roller 642 conveys the magnetic brush to the opposing position of the scraper 645 by rotating. The scraper 645 is configured to form a gap (gap) between it and the magnetic roller 642. Therefore, the thickness of the magnetic brush is defined by the scraper 645. In the rotation direction of the magnetic roller 642, the scraper 645 is configured on the upstream side of the opposing position of the magnetic roller 642 and the developing roller 641.

[0193] A predetermined voltage is applied to the developing roller 641 and the magnetic roller 642. When the predetermined voltage is applied, a predetermined potential difference is generated between the developing roller 641 and the magnetic roller 642, whereby the yellow toner contained in the two-component developer moves to the developing roller 641. As a result, a thin toner layer composed of the yellow toner is formed on the surface of the developing roller 641.

[0194] The developing roller 641 moves along Figure 5 The developing device 64 rotates in the direction indicated by the arrow R2 (counterclockwise). As a result, the thin layer of toner formed on the surface is transported to a position opposite to the image carrier 65 and then adheres to the image carrier 65. As a result, the developing device 64 supplies the toner charged by friction with the carrier to the surface of the image carrier 65.

[0195] As mentioned above, refer to Figure 5 , the developing device 64 of the first image forming unit 62Y is described. The developing devices 64 of the first to fourth image forming units 62Y to 62K are identical in structure except for the type of toner replenished from the toner replenishing unit 50. Therefore, the structural description of the developing devices 64 of the second to fourth image forming units 62C to 62K is omitted.

[0196] As mentioned above, refer to Figure 4 and Figure 5An example of an image forming apparatus is described, but the image forming apparatus is not limited to the above-mentioned image forming apparatus 100. The above-mentioned image forming apparatus 100 is a color image forming apparatus, but the image forming apparatus may also be a monochrome image forming apparatus. In such a case, the image forming apparatus may only have one image forming unit, for example. In addition, the above-mentioned image forming apparatus 100 adopts a tandem method, but the image forming apparatus may also adopt a rotary method, for example. The charging roller is described as an example of the charging device 63, but the charging device may also be a charging device other than a charging roller (for example, a grid corotron charger, a charging brush, or a corotron charger). The above-mentioned image forming apparatus 100 adopts a two-component development method using a two-component developer, but the image forming apparatus may also adopt a single-component development method using a single-component developer. The above-mentioned image forming apparatus 100 adopts a touchdown development method, but the image forming apparatus may also adopt a development method other than the touchdown development method (for example, a development method in which a magnetic roller has the function of a developing roller but does not have a developing roller). The image forming apparatus 100 adopts an intermediate transfer method, but the image forming apparatus may also adopt a direct transfer method. In the case where the image forming apparatus adopts a direct transfer method, the image carrier 65 contacts the recording medium P and directly transfers the toner image from the image carrier 65 to the recording medium P. A cleaning blade is used as an example of the cleaning member 661, but the cleaning member may also be a cleaning roller. In addition, the image forming apparatus may not include the cleaning device 66. In addition, the first image forming unit 62Y to the fourth image forming unit 62K are provided with an anti-static device 67, but the image forming unit may not include an anti-static device.

[0197] <Third Embodiment: Process Cartridge>

[0198] Next, continue to refer to Figure 4 , a processing box of the third embodiment of the present invention is described. The processing box of the third embodiment is equivalent to each of the first image forming unit 62Y to the fourth image forming unit 62K. The processing box includes an image carrier 65. The image carrier 65 is the photosensitive body 1 of the first embodiment. As described in the first embodiment, the photosensitive layer is well formed in the photosensitive body 1 of the first embodiment, and the photosensitive body 1 of the first embodiment has excellent charging stability and can suppress transfer memory. Therefore, the photosensitive layer of the photosensitive body 1 as the image carrier 65 is well formed in the processing box of the third embodiment, has excellent charging stability and can suppress transfer memory.

[0199] In addition to the image carrier 65, the processing box further includes at least one (for example, more than one and less than six) selected from the group consisting of a charging device 63, an exposure device 61, a developing device 64, a transfer device 70 (especially a primary transfer roller 71), a cleaning device 66, and an anti-static device 67. The processing box is designed to be attachable and detachable relative to the image forming device 100. Therefore, the processing box is easy to handle, and when the sensitivity characteristics of the image carrier 65 deteriorate, the components including the image carrier 65 can be easily and quickly replaced. As described above, refer to Figure 4 The process cartridge of the third embodiment has been described.

[0200] [Example]

[0201] Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to the scope of the examples in any way.

[0202] First, as materials for forming a photosensitive layer of a photoreceptor, the following charge generating agent, first electron transporting agent, second electron transporting agent, hole transporting agent, and polyarylate resin as a binder resin are prepared.

[0203] <Charge Generator, First Electron Transporter, Second Electron Transporter, and Hole Transporter>

[0204] Prepare the Y-type oxytitanium phthalocyanine and X-type metal-free phthalocyanine described in the first embodiment as charge generating agents. Prepare each of the electron transport agents (E-1) to (E-3) described in the first embodiment as a first electron transport agent. Prepare each of the electron transport agents (E-4) to (E-8) described in the first embodiment as a second electron transport agent. In addition, prepare a compound represented by the following formula (EA) (hereinafter sometimes described as electron transport agent (EA)) as a second electron transport agent used in the comparative example. Prepare the hole transport agents (H-1) to (H-8) described in the first embodiment as a hole transport agent.

[0205]

[0206] <Polyarylate resins A to L and N to O>

[0207] The polyarylate resins A to J according to the examples and the polyarylate resins K to L and N to O according to the comparative examples were synthesized by the following method. The compositions of the polyarylate resins A to L and N to O are shown in Table 3 below.

[0208]

Table 3

[0209]

[0210] In Table 3, "BisCZ", "BisB", "BisZ", "BP", "14NACC", "26NACC" and "DPEC" represent compounds represented by the following formulas (BisCZ), (BisB), (BisZ), (BP), (14NACC), (26NACC) and (DPEC), respectively (hereinafter, sometimes described as compounds (BisCZ), (BisB), (BisZ), (BP), (14NACC), (26NACC) and (DPEC), respectively).

[0211]

[0212] In addition, the meanings of the terms in Table 3 are as follows.

[0213] Monomer: Monomer used in the synthesis of polyarylate resin

[0214] Molding unit: The repeating unit formed by this monomer

[0215] Resin: Polyarylate resin

[0216] Bisphenol addition rate: the percentage (unit: %) of the amount of bisphenol monomer (unit: mole) relative to the total amount of bisphenol monomer (unit: mole) added in the synthesis of polyarylate resin

[0217] Dicarboxylic acid addition rate: the percentage (unit: %) of the amount (unit: mole) of the dicarboxylic acid monomer relative to the total amount (unit: mole) of the dicarboxylic acid monomer added in the synthesis of the polyarylate resin

[0218] Molecular weight: viscosity average molecular weight

[0219] Unit: Repeating unit

[0220] DMP: 2,6-dimethylphenol

[0221] PFH: 1H,1H-perfluoro-1-heptanol

[0222] Unable to measure: Polyarylate resin is not soluble in the solvent used for viscosity and molecular weight measurement, so the viscosity average molecular weight cannot be measured.

[0223] (Synthesis of polyarylate resin A)

[0224] A three-necked flask equipped with a thermometer, a three-way valve and a dropping funnel was used as a reaction container. In the reaction container, a monomer compound (BisCZ) (38.95 mmol), a monomer compound (BP) (2.05 mmol), a terminal terminator 2,6-dimethylphenol (0.413 mmol), sodium hydroxide (98 mmol), and benzyltributylammonium chloride (0.384 mmol) were placed. The air in the reaction container was replaced with argon. Water (300 mL) was added to the contents of the reaction container. The contents of the reaction container were stirred at 50°C for 1 hour. The contents of the reaction container were cooled to 10°C to obtain an alkaline aqueous solution SA.

[0225] Next, dicarboxylic acid dichloride (16.0 mmol) of the compound (14NACC) as a monomer and dicarboxylic acid dichloride (16.0 mmol) of the compound (26NACC) as a monomer were dissolved in chloroform (150 mL), thereby obtaining a chloroform solution SB.

[0226] Using a dropping funnel, slowly add chloroform solution SB to the alkaline aqueous solution SA over 110 minutes. Adjust the temperature (liquid temperature) of the contents of the reaction container to 15±5°C, and stir the contents of the reaction container for 4 hours to carry out a polymerization reaction. Use a decanter to remove the upper layer (water layer) in the contents of the reaction container to obtain an organic layer. Then, add ion exchange water (400mL) to the conical flask. Add the obtained organic layer to the conical flask. Further add chloroform (400mL) and acetic acid (2mL) to the conical flask. Stir the contents of the conical flask at room temperature (25°C) for 30 minutes. Use a decanter to remove the upper layer (water layer) in the contents of the conical flask to obtain an organic layer. Use a separatory funnel to wash the obtained organic layer with ion exchange water (1L). Repeat the washing with ion exchange water 5 times to obtain a washed organic layer. Next, filter the washed organic layer to obtain a filtrate. The obtained filtrate was slowly added dropwise to methanol (1 L) to obtain a precipitate. The precipitate was taken out by filtration. The taken out precipitate was vacuum dried at a temperature of 70° C. for 12 hours. As a result, polyarylate resin A was obtained.

[0227] (Synthesis of polyarylate resins B-L and N-O)

[0228] Each of polyarylate resins B to L and N to O was synthesized according to the synthesis method of polyarylate resin A, except that the monomers in Table 3 were used at the addition rates in Table 3. In addition, the addition amount of each bisphenol monomer was set so that the total amount of bisphenol monomers was 41.0 mmol and the bisphenol addition rate in Table 3 was achieved. For example, in the synthesis of polyarylate resin B, the addition amount of compound (BisB) was 38.95 mmol (= 41.0 × 95 / 100), and the addition amount of compound (BP) was 2.05 mmol (= 41.0 × 5 / 100). In addition, the addition amount of each dicarboxylic acid monomer was set so that the total amount of dicarboxylic acid monomers was 32.0 mmol and the dicarboxylic acid addition rate in Table 3 was achieved. For example, in the synthesis of polyarylate resin B, the amount of compound (14NACC) added was 16.0 mmol (= 32.0×50 / 100), and the amount of compound (26NACC) added was 16.0 mmol (= 32.0×50 / 100).

[0229] The obtained polyarylate resins A to L and N to O were measured using a proton nuclear magnetic resonance spectrometer (manufactured by JEOL Ltd., 600 MHz). 1 H-NMR spectrum. Deuterated chloroform was used as solvent. Tetramethylsilane (TMS) was used as internal standard. Representative examples of polyarylate resins A to L and N to O include polyarylate resin H. 1 The H-NMR spectrum shows Figure 6 According to 1 The chemical shift read from the H-NMR spectrum confirmed the presence of polyarylate resin H. The presence of polyarylate resins A to G, I to L, and N to O was also confirmed by the same method.

[0230] <Polyarylate resin M>

[0231] Prepare the polyarylate resin M involved in the comparative example. The polyarylate resin M is represented by the following formula (M). The number at the lower right corner of the repeating unit derived from bisphenol in the formula (M) represents: the content rate (unit: %) of the repeating unit derived from bisphenol relative to the total number of repeating units derived from bisphenol contained in the polyarylate resin M. In addition, the number at the lower right corner of the repeating unit derived from dicarboxylic acid in the formula (M) represents: the content rate (unit: %) of the repeating unit derived from dicarboxylic acid relative to the total number of repeating units derived from dicarboxylic acid contained in the polyarylate resin M. In the polyarylate resin M, the terminal group is the terminal group derived from 2,6-dimethylphenol. The viscosity average molecular weight of the polyarylate resin M is 54400.

[0232]

[0233] <Measurement of viscosity average molecular weight>

[0234] The viscosity average molecular weight of the polyarylate resin was measured in accordance with JIS (Japanese Industrial Standard) K7252-1: 2016. The measured viscosity average molecular weight is shown in Table 3.

[0235] <Manufacturing of photoreceptors>

[0236] (Manufacturing of Photoreceptor (A-1))

[0237] Using a rod-shaped sonic oscillator, 2 parts by mass of Y-type oxytitanium phthalocyanine as a charge generating agent, 70 parts by mass of a hole transport agent (H-1), 25 parts by mass of an electron transport agent (E-1) as a first electron transport agent, 25 parts by mass of an electron transport agent (E-4) as a second electron transport agent, 100 parts by mass of a polyarylate resin A as a binder resin, and 500 parts by mass of tetrahydrofuran as a solvent were mixed for 20 minutes to obtain a dispersion. The dispersion was filtered using a filter with a pore size of 5 μm to obtain a coating liquid for a photosensitive layer. The coating liquid for a photosensitive layer was applied to a conductive substrate (aluminum drum-shaped support) by dip coating, and hot air dried at 120°C for 50 minutes. Thus, a photosensitive layer (film thickness 30 μm) was formed on the conductive substrate to obtain a photoreceptor (A-1). In the photoreceptor (A-1), a single-layer photosensitive layer is directly formed on the conductive substrate.

[0238] (Manufacturing of Photoreceptors (A-2) to (A-5), (A-8) to (A-35), and (B-1) to (B-14))

[0239] Photoreceptors (A-2) to (A-5), (A-8) to (A-35), and (B-1) to (B-14) were obtained according to the method for producing photoreceptor (A-1), except that the charge generating agent, hole transporting agent, first electron transporting agent, second electron transporting agent, and binder resin in Tables 4 to 7 were used. In addition, regarding photoreceptors (B-13) and (B-14), the binder resin was insoluble in the solvent for the coating solution for forming the photosensitive layer, and thus the production could not be performed.

[0240] (Manufacturing of Photoreceptor (A-6))

[0241] Photoreceptor (A-6) was produced according to the method for producing photoreceptor (A-1), except that 40 parts by mass of electron transport agent (E-1) and 10 parts by mass of electron transport agent (E-4) were added instead of 25 parts by mass of electron transport agent (E-1) and 25 parts by mass of electron transport agent (E-4).

[0242] (Manufacturing of Photoreceptor (A-7))

[0243] Photoreceptor (A-7) was produced according to the method for producing photoreceptor (A-1), except that 10 parts by mass of electron transport agent (E-1) and 40 parts by mass of electron transport agent (E-4) were added instead of 25 parts by mass of electron transport agent (E-1) and 25 parts by mass of electron transport agent (E-4).

[0244] (Manufacturing of Photoreceptor (B-15))

[0245] Photoreceptor (B-15) was manufactured according to the manufacturing method of photoreceptor (A-1), except that 25 parts by mass of electron transport agent (E-1) as the first electron transport agent and 25 parts by mass of electron transport agent (E-2) as the first electron transport agent were added to replace 25 parts by mass of electron transport agent (E-1) as the first electron transport agent and 25 parts by mass of electron transport agent (E-4) as the second electron transport agent. In addition, in the manufacture of photoreceptor (B-15), no second electron transport agent was added.

[0246] (Manufacturing of Photoreceptor (B-16))

[0247] Photoreceptor (B-16) was manufactured according to the manufacturing method of photoreceptor (A-1), except that 25 parts by mass of electron transport agent (E-2) as the first electron transport agent and 25 parts by mass of electron transport agent (E-3) as the first electron transport agent were added to replace 25 parts by mass of electron transport agent (E-1) as the first electron transport agent and 25 parts by mass of electron transport agent (E-4) as the second electron transport agent. In addition, in the manufacture of photoreceptor (B-16), no second electron transport agent was added.

[0248] (Manufacturing of Photoreceptor (B-17))

[0249] Photoreceptor (B-17) was manufactured according to the manufacturing method of photoreceptor (A-1), except that 25 parts by mass of electron transport agent (E-4) as the second electron transport agent and 25 parts by mass of electron transport agent (E-5) as the second electron transport agent were added to replace 25 parts by mass of electron transport agent (E-1) as the first electron transport agent and 25 parts by mass of electron transport agent (E-4) as the second electron transport agent. In addition, in the manufacture of photoreceptor (B-17), the first electron transport agent was not added.

[0250] (Manufacturing of Photoreceptor (B-18))

[0251] Photoreceptor (B-18) was manufactured according to the manufacturing method of photoreceptor (A-1), except that 25 parts by mass of electron transport agent (E-4) as the second electron transport agent and 25 parts by mass of electron transport agent (E-6) as the second electron transport agent were added to replace 25 parts by mass of electron transport agent (E-1) as the first electron transport agent and 25 parts by mass of electron transport agent (E-4) as the second electron transport agent. In addition, in the manufacture of photoreceptor (B-18), the first electron transport agent was not added.

[0252] (Manufacturing of Photoreceptor (B-19))

[0253] Photoreceptor (B-19) was manufactured according to the manufacturing method of photoreceptor (A-1), except that 25 parts by mass of electron transport agent (E-5) as the second electron transport agent and 25 parts by mass of electron transport agent (E-6) as the second electron transport agent were added to replace 25 parts by mass of electron transport agent (E-1) as the first electron transport agent and 25 parts by mass of electron transport agent (E-4) as the second electron transport agent. In addition, in the manufacture of photoreceptor (B-19), the first electron transport agent was not added.

[0254] (Manufacturing of Photoreceptor (B-20))

[0255] Photoreceptor (B-20) was manufactured according to the manufacturing method of photoreceptor (A-1), except that 25 parts by mass of electron transport agent (E-5) as the second electron transport agent and 25 parts by mass of electron transport agent (E-7) as the second electron transport agent were added to replace 25 parts by mass of electron transport agent (E-1) as the first electron transport agent and 25 parts by mass of electron transport agent (E-4) as the second electron transport agent. In addition, in the manufacture of photoreceptor (B-20), the first electron transport agent was not added.

[0256] <Evaluation>

[0257] For each of the obtained photoreceptors, the charging stability, sensitivity characteristics and inhibition of transfer memory were evaluated according to the following method. These evaluations were carried out in an environment with a temperature of 23°C and a relative humidity of 50% RH. The photoreceptor was installed in an evaluation machine. A modified machine of an image forming apparatus ("FS-C5250DN" manufactured by Kyocera Document Systems, Ltd.) was used as an evaluation machine for carrying out these evaluations. The evaluation machine is provided with a charging roller composed of an epichlorohydrin resin in which conductive carbon is dispersed, as a charging device. The charging polarity of the charging roller is positive polarity, and the applied voltage of the charging roller is a DC voltage. In addition, in the evaluation machine, a two-component development method and an intermediate transfer method are adopted. In addition, in the evaluation machine, a cleaning scraper and an anti-static device are provided.

[0258] <Evaluation of charging stability>

[0259] The applied voltage of the charging roller was set to +1.4 kV. The photoreceptor was charged using an evaluation machine, and the first charging potential V was measured at the developing position. 01 (Unit: +V). Then, using the evaluation machine, the photoreceptor is charged and static-free repeatedly for 30 minutes, and the charge potential is continuously measured at the developing position during the 30 minutes. Next, the minimum value of the charge potentials continuously measured during the 30 minutes is taken as the second charge potential V 02 (Unit: +V). According to the calculation formula "ΔV0 = V 02 -V 01 ", and the charge potential change ΔV0 (unit: V) is calculated. ΔV0 is shown in Tables 4 to 7. The smaller the absolute value of ΔV0 is, the more stable the charge potential of the photoreceptor is, and the better the charge stability is.

[0260] <Evaluation of sensitivity characteristics and transfer memory suppression>

[0261] The applied voltage of the charging roller was set so that the charged potential of the photoreceptor reached +570 V. The exposure light used by the exposure device was set to have a wavelength of 780 nm, a half width of 20 nm, and a light intensity of 1.16 μJ / m 2 The transfer bias voltage of the primary transfer roller was set to -2.0 kV.

[0262] Using an evaluation machine, charge the photoreceptor and expose it. At the development position, measure the surface potential of the exposed area (equivalent to the image area) and the surface potential of the non-exposed area (equivalent to the blank area). The measured surface potential of the exposed area is taken as the post-exposure potential VL (unit: +V). The measured surface potential of the non-exposed area is taken as the non-exposed area potential V3 before transfer (unit: +V).

[0263] Then, a transfer bias is applied to the photoreceptor. Then, the photoreceptor is subjected to static elimination, and then the photoreceptor is charged, and the surface potential of the non-exposed area (equivalent to the blank area) is measured at the developing position. The measured surface potential of the non-exposed area is taken as the non-exposed area potential V4 after transfer (unit: +V).

[0264] The potential VL after exposure is shown in Tables 4 to 7. The photoreceptor having a VL of +130 V or less was evaluated to have good sensitivity characteristics.

[0265] In addition, the transfer memory potential ΔVtc (unit: V) was obtained according to the calculation formula "ΔVtc = V3 - V4". ΔVtc is shown in Tables 4 to 7. The smaller the absolute value of ΔVtc is, the better the transfer memory is suppressed.

[0266] The meanings of the technical terms in Tables 4 to 7 are as follows. "CGM" represents a charge generating agent. "CG-1" represents Y-type oxytitanium phthalocyanine. "CG-2" represents X-type metal-free phthalocyanine. "HTM" represents a hole transport agent. "First ETM" represents a first electron transport agent. "Second ETM" represents a second electron transport agent. "First ETM / Second ETM" represents the ratio M1 / M2 of the mass of the first electron transport agent M1 to the mass of the second electron transport agent M2. In addition, in the manufacture of any photoreceptor, the total mass of the added electron transport agent is 50 parts by mass. The added amounts of the first electron transport agent and the second electron transport agent are adjusted so that the total mass of the electron transport agent is 50 parts by mass and the ratio M1 / M2 is the value shown in the "First ETM / Second ETM" column of Tables 4 to 7. "Resin" represents a polyarylate resin as a binding resin. "ΔV0" represents the amount of change in the charged potential (unit: V). "VL" represents the potential after exposure (unit: +V). "ΔVtc" indicates the transfer memory potential (unit: V). "Unable to prepare" indicates that the polyarylate resin is insoluble in the solvent used to form the photosensitive layer coating solution, and the photosensitive layer coating solution cannot be prepared, so the evaluation and measurement cannot be performed. "-" indicates that the material is not used, or that there is no corresponding value.

[0267]

Table 4

[0268]

[0269]

Table 5

[0270]

[0271]

Table 6

[0272]

[0273]

Table 7

[0274]

[0275] As shown in Tables 4 to 5, the photosensitive layer of the photoreceptors (A-1) to (A-35) contains a charge generating agent, a hole transporting agent, a first electron transporting agent, a second electron transporting agent and a polyarylate resin. The polyarylate resin is a polyarylate resin (PA) (more specifically, one of the polyarylate resins A to J). The first electron transporting agent contains a first electron transporting agent (A15) or (A16) (more specifically, one of the electron transporting agents (E-1) to (E-3)). The second electron transporting agent contains a second electron transporting agent (B10), (B11), (B12), (B13) or (B14) (more specifically, one of the electron transporting agents (E-4) to (E-8)).

[0276] On the other hand, as shown in Table 6, the photosensitive layer of photoreceptors (B-1) to (B-9) contains an electron transport agent (EA) as a second electron transport agent, but the electron transport agent (EA) is not a compound included in formulas (B10), (B11), (B12), (B13) and (B14). As shown in Table 7, the photosensitive layer of photoreceptors (B-10) to (B-14) does not contain polyarylate resin (PA). As shown in Table 7, the photosensitive layer of photoreceptors (B-15) to (B-16) contains two electron transport agents, but both electron transport agents are first electron transport agents and do not contain a second electron transport agent. As shown in Table 7, the photosensitive layer of photoreceptors (B-17) to (B-20) contains two electron transport agents, but both electron transport agents are second electron transport agents and do not contain a first electron transport agent.

[0277] As shown in Tables 4, 5 and 7, photosensitive layers were well formed in photoreceptors (A-1) to (A-35) compared with photoreceptors (B-13) and (B-14). Also, as shown in Tables 4 to 7, the absolute value of the charge potential change ΔV0 of photoreceptors (A-1) to (A-35) was small compared with photoreceptors (B-1) to (B-12) and (B-15) to (B-20), and the charge stability was good. Also, the absolute value of the transfer memory potential ΔVtc of photoreceptors (A-1) to (A-35) was small compared with photoreceptors (B-1) to (B-12) and (B-15) to (B-20), and the transfer memory was suppressed. In addition, the post-exposure potential VL of the photoreceptors (A-1) to (A-35) was +130 V or less, and the photoreceptors (A-1) to (A-35) improved charging stability and suppressed transfer memory without impairing sensitivity characteristics.

[0278] In summary, the photosensitive layer is well formed in the photoreceptor of the present invention including the photoreceptors (A-1) to (A-35), and the photoreceptor exhibits excellent charging stability and can suppress transfer memory. In addition, it can be seen that the process cartridge and the image forming apparatus of the present invention include a photoreceptor, in which a photosensitive layer is well formed, and the photoreceptor has excellent charging stability and can suppress transfer memory.

Claims

1. An electrophotographic photoreceptor, It has a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer, The photosensitive layer contains a charge generating agent, a hole transporting agent, a first electron transporting agent, a second electron transporting agent and a binding resin. The binding resin contains a polyarylate resin, The polyarylate resin has repeating units represented by formulae (1), (2), (3) and (4), wherein the content of the repeating unit represented by formula (3) is greater than 0% and less than 20% relative to the total amount of the repeating units represented by formulae (1) and (3), The first electron transport agent contains a compound represented by formula (A15) or (A16), The second electron transport agent contains a compound represented by formula (B10), (B11), (B12), (B13) or (B14), The ratio M1 / M2 of the mass M1 of the first electron transport agent to the mass M2 of the second electron transport agent is 0.25 or more and 4.00 or less, The total content of the first electron transport agent and the second electron transport agent is 30 parts by mass or more and 70 parts by mass or less relative to 100 parts by mass of the binder resin. In the formula (1), R 1 and R 2 Each independently represents a hydrogen atom or a methyl group, X is a divalent group represented by formula (X1) or (X2), In the formula (2), W is a divalent group represented by the formula (W1) or (W2), In the formula (X1), t represents an integer of 1 to 3, * represents a bonding bond, In the formula (X2), R 3 and R 4 represents a hydrogen atom or a C1-C4 alkyl group, R 3 and R 4 Indicates different bases, * indicates a bond, In the formula (W1) and the formula (W2), * represents a bond, Q in the formula (A15) 51 , Q 52 , Q 53 , Q 54 , Q 55 and Q 56 , Q in the formula (A16) 61 and Q 62 , Q in the formula (B10) 1 and Q 2 , Q in the formula (B11) 11 , Q 12 and Q 13 , Q in the formula (B12) 21 , Q 22 , Q 23 and Q 24 , Q in the formula (B13) 31 and Q 32 And Q in the formula (B14) 41 , Q 42 , Q 43 and Q 44 Each independently represents a hydrogen atom, a halogen atom, a cyano group, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C1-C6 alkoxy group, an unsubstituted C6-C14 aryl group, or a C6-C14 aryl group substituted with at least one substituent selected from the group consisting of a C1-C6 alkyl group and a halogen atom, In the formula (A15), Y 1 and Y 2 Each independently represents an oxygen atom or a sulfur atom.

2. The electrophotographic photoreceptor according to claim 1, wherein The compound represented by formula (A15) is a compound represented by formula (E-2) or (E-3), The compound represented by formula (A16) is a compound represented by formula (E-1), 3. The electrophotographic photoreceptor according to claim 1 or 2, characterized in that: The compound represented by formula (B10) is a compound represented by formula (E-4), The compound represented by formula (B11) is a compound represented by formula (E-5), The compound represented by formula (B12) is a compound represented by formula (E-7), The compound represented by formula (B13) is a compound represented by formula (E-6), The compound represented by formula (B14) is a compound represented by formula (E-8), 4. The electrophotographic photoreceptor according to claim 1 or 2, characterized in that: In the formula (1), R 1 and R 2 represents a methyl group, and X is a divalent group represented by the above formula (X1).

5. The electrophotographic photoreceptor according to claim 1 or 2, characterized in that: The repeating unit represented by the formula (1) is the repeating unit represented by the formula (1-1), the repeating unit represented by the formula (2) is the repeating unit represented by the formula (2-1), 6. The electrophotographic photoreceptor according to claim 1 or 2, characterized in that: The repeating unit represented by the formula (1) is the repeating unit represented by the formula (1-1), the repeating unit represented by the formula (2) is the repeating unit represented by the formula (2-2), 7. The electrophotographic photoreceptor according to claim 1 or 2, characterized in that: The repeating unit represented by the formula (1) is the repeating unit represented by the formula (1-2), the repeating unit represented by the formula (2) is the repeating unit represented by the formula (2-1), 8. The electrophotographic photoreceptor according to claim 1 or 2, characterized in that: The hole transport agent is a compound represented by formula (21), (22) or (23), In the formula (21), R 21 , R 22 and R 23 Each independently represents a C1-C6 alkyl group, R 24 , R 25 and R 26 Each independently represents a hydrogen atom or a C1-C6 alkyl group, b1, b2 and b3 each independently represent 0 or 1, In the formula (22), R 31 , R 32 and R 33 Each independently represents a C1-C6 alkyl group, R 34 represents a C1-C6 alkyl group or a hydrogen atom, d1, d2 and d3 each independently represent an integer of 0 to 5, In the formula (23), R 50 and R 51 Each independently represents a C1-C6 alkyl group, a C1-C6 alkoxy group or a phenyl group, R 52 , R 53 , R 54 , R 55 , R 56 , R 57 and R 58 Each independently represents a hydrogen atom, a C1-C6 alkyl group, a C1-C6 alkoxy group, an unsubstituted phenyl group or a phenyl group having a C1-C6 alkyl substituent, f1 and f2 each independently represent an integer greater than 0 and less than 2, and f3 and f4 each independently represent an integer greater than 0 and less than 5.

9. A process cartridge comprising: at least one device selected from the group consisting of a charging device, an exposure device, a developing device, a transfer device, a cleaning device, and an antistatic device; and The electrophotographic photoreceptor according to any one of claims 1 to 8.

10. An image forming device comprising: Image carrier; A charging device for charging the surface of the image bearing body; an exposure device for exposing the charged surface of the image carrier to form an electrostatic latent image on the surface of the image carrier; a developing device for supplying toner to the surface of the image bearing member to develop the electrostatic latent image into a toner image; as well as a transfer device for transferring the toner image from the image bearing body to a transfer body, The image bearing member is the electrophotographic photoreceptor according to any one of claims 1 to 8.

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