Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Abstract

An electrophotographic photoreceptor, a process cartridge, and an image forming apparatus, the electrophotographic photoreceptor including a conductive substrate and a photosensitive layer disposed on the conductive substrate, the outermost layer being a layer containing a charge transport material and a binder resin and having a breaking energy of 10 mJ / mm3 or more, and the kinetic friction coefficient of the outer peripheral surface being 0.5-1.0.

Description

Technical Field

[0001] The present invention relates to an electronic photographic photosensitive body, a processing box and an image forming device. Background Art

[0002] Patent document 1 discloses a cleaning device for cleaning a movable photosensitive drum of an image forming device that forms an image on a recording sheet, the cleaning device having a cleaning component that abuts against the photosensitive drum and removes residual toner on the photosensitive drum, and when the amount of wear of the surface layer of the photosensitive drum in a TABER wear tester is less than 1.5 mg, the dynamic friction coefficient between the surface layer of the photosensitive drum and the cleaning component is within the range of a dynamic friction coefficient measured at a scanning speed of 50 mm / min ≤ 0.9 and a dynamic friction coefficient measured at a scanning speed of 3 mm / min ≤ a dynamic friction coefficient measured at a scanning speed of 50 mm / min × 1.1.

[0003] Patent document 2 discloses an image forming method in which a plurality of images are formed by repeating the steps of charging, image exposure, development, transfer and cleaning with a cleaning scraper on an electronic photographic photoreceptor, wherein the static friction coefficient of the photoreceptor relative to the cleaning scraper is set to less than 1.0, the cleaning scraper is brought into contact with the photoreceptor in the opposite direction and is vibrated at a vibration magnitude of 10 to 200 μm for cleaning.

[0004] Patent document 3 discloses an image forming method, which includes a process of imparting uniform charging to a traveling electronic photographic photoreceptor; a process of forming an electrostatic latent image by image exposure; and the processes of development, transfer and cleaning. A photoreceptor having a photosensitive layer containing an organic photoconductive material is used as the photoreceptor, and a rubber elastic cleaning scraper with a rebound resilience of 35 to 75% is used as a cleaning component in the cleaning process. The cleaning scraper is brought into contact with the photoreceptor at an angle in the opposite direction, and the static friction coefficient of the surface layer of the photoreceptor relative to the cleaning scraper is set to be in the range of 0.1 to 1.0.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2002-333804

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 09-090843

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 08-083028 Summary of the invention

[0008] The present invention aims to provide a method for producing a thin film having a fracture energy of less than 10 mJ / mm 3 Or an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the dynamic friction coefficient of the outer peripheral surface is less than 0.5 or exceeds 1.0.

[0009] Specific means for solving the above-mentioned problems include the following aspects. Each formula is the same as the formula with the same number described below.

[0010] <1> An electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer disposed on the conductive substrate, wherein:

[0011] The outermost layer contains charge transport material and adhesive resin and has a breaking energy of 10mJ / mm 3 The above layers,

[0012] The coefficient of dynamic friction of the outer peripheral surface is 0.5 or more and 1.0 or less.

[0013] <2> The electrophotographic photoreceptor according to <1>, wherein

[0014] The dynamic friction coefficient divided by the fracture energy (mJ / mm 3 ) is greater than or equal to 0.05 and less than or equal to 0.10.

[0015] <3> The electrophotographic photoreceptor according to <1> or <2>, wherein

[0016] The binder resin includes a polyester resin, and a ratio of the polyester resin in the binder resin is 35 mass % or more and 75 mass % or less.

[0017] <4> The electrophotographic photoreceptor according to any one of <1> to <3>, wherein

[0018] The ratio of the binder resin in the outermost surface layer is 50% by mass or more.

[0019] <5> The electrophotographic photoreceptor according to any one of <1> to <4>, wherein

[0020] The ratio of the binder resin in the outermost surface layer is 55 mass % or more and 70 mass % or less.

[0021] <6> The electrophotographic photoreceptor according to any one of <1> to <5>, wherein

[0022] The binding resin includes two or more resins.

[0023] <7> The electrophotographic photoreceptor according to <6>, wherein

[0024] The two or more resins include a polyester resin (1) having a dicarboxylic acid unit (A) represented by the formula (A) and a diol unit (B) represented by the formula (B).

[0025] <8> The electrophotographic photoreceptor according to <7>, wherein

[0026] The dicarboxylic acid unit (A) represented by the formula (A) includes at least one selected from the group consisting of a dicarboxylic acid unit (A1) represented by the formula (A1), a dicarboxylic acid unit (A2) represented by the formula (A2), a dicarboxylic acid unit (A3) represented by the formula (A3), and a dicarboxylic acid unit (A4) represented by the formula (A4).

[0027] <9> The electrophotographic photoreceptor according to <7> or <8>, wherein

[0028] The diol unit (B) represented by the formula (B) includes at least one selected from the group consisting of a diol unit (B1) represented by the formula (B1), a diol unit (B2) represented by the formula (B2), a diol unit (B3) represented by the formula (B3), a diol unit (B4) represented by the formula (B4), a diol unit (B5) represented by the formula (B5), a diol unit (B6) represented by the formula (B6), a diol unit (B7) represented by the formula (B7) and a diol unit (B8) represented by the formula (B8).

[0029] <10> The electrophotographic photoreceptor according to any one of <6> to <9>, wherein

[0030] The two or more resins include a polycarbonate resin.

[0031] <11> The electrophotographic photoreceptor according to any one of <1> to <10>, wherein

[0032] The photosensitive layer has a charge generating layer and a charge transporting layer, and the charge transporting layer is the outermost layer.

[0033] <12> A process cartridge comprising:

[0034] The electrophotographic photoreceptor according to any one of <1> to <11>; and

[0035] a charging device for charging the surface of the electrophotographic photoreceptor and having a charging member in direct contact with the electrophotographic photoreceptor, wherein a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the charging member;

[0036] The process cartridge is attachable to and detachable from the image forming apparatus.

[0037] <13> An image forming apparatus comprising:

[0038] The electrophotographic photoreceptor according to any one of <1> to <11>;

[0039] a charging device for charging the surface of the electrophotographic photoreceptor and having a charging member in direct contact with the electrophotographic photoreceptor, wherein a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the charging member;

[0040] An electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;

[0041] a developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image;

[0042] a transfer device for transferring the toner image to a surface of a recording medium; and

[0043] A cleaning device cleans the surface of the electrophotographic photoreceptor.

[0044] Effects of the Invention

[0045] According to <1> or <11>, there is provided a method of providing ... 3 Or an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the dynamic friction coefficient of the outer peripheral surface is less than 0.5 or exceeds 1.0.

[0046] According to <2>, an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the value of the dynamic friction coefficient divided by the breaking energy is less than 0.05 or exceeds 0.10 is provided.

[0047] According to <3>, an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the proportion of the polyester resin in the binder resin is less than 35 mass % or exceeds 75 mass %.

[0048] According to <4>, an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the ratio of the binder resin in the outermost surface layer is less than 50 mass % is provided.

[0049] According to <5>, an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance is provided compared with a case where the ratio of the binder resin in the outermost surface layer is less than 55 mass % or exceeds 70 mass %.

[0050] According to <6>, <7>, <8>, <9> or <10>, there is provided an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the binder resin is a single resin.

[0051] According to <12>, there is provided a process cartridge comprising an electrophotographic photoreceptor having a fracture energy of less than 10 mJ / mm 3Or an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the dynamic friction coefficient of the outer peripheral surface is less than 0.5 or exceeds 1.0.

[0052] According to <13>, there is provided an image forming apparatus comprising an electrophotographic photoreceptor having a fracture energy of less than 10 mJ / mm 3 Or an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the dynamic friction coefficient of the outer peripheral surface is less than 0.5 or exceeds 1.0. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0054] Figure 1 is a partial cross-sectional view showing an example of a layer structure of an electrophotographic photoreceptor according to the present embodiment;

[0055] Figure 2 is a partial cross-sectional view showing another example of the layer structure of the electrophotographic photoreceptor involved in this embodiment;

[0056] Figure 3 is a schematic structural diagram showing an example of an image forming apparatus according to the present embodiment;

[0057] Figure 4 It is a schematic configuration diagram showing another example of the image forming apparatus according to the present embodiment.

[0058] Explanation of symbols

[0059] 1-conductive substrate, 2-undercoat layer, 3-charge generating layer, 4-charge transport layer, 5-photosensitive layer, 10A-photosensitive body, 10B-photosensitive body. 7-electrophotographic photosensitive body, 8-charging device, 9-exposure device, 11-developing device, 13-cleaning device, 14-lubricant, 40-transfer device, 50-intermediate transfer body, 100-image forming device, 120-image forming device, 131-cleaning blade, 132-fibrous member (roller), 133-fibrous member (flat brush), 300-processing box. DETAILED DESCRIPTION

[0060] Hereinafter, embodiments of the present invention will be described. These descriptions and examples are intended to illustrate the embodiments and do not limit the scope of the embodiments.

[0061] In the present invention, a numerical range expressed using "to" indicates a range including the numerical values ​​before and after "to" as the minimum value and the maximum value, respectively.

[0062] In the numerical ranges recorded in stages in the present invention, the upper limit or lower limit recorded in one numerical range may also be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical ranges recorded in the present invention, the upper limit or lower limit of the numerical range may also be replaced by the value shown in the embodiment.

[0063] In the present invention, the word "process" is included in this term if the purpose of the process can be achieved not only in an independent process but also in a case where the process cannot be clearly distinguished from other processes.

[0064] In the present invention, when the embodiments are described with reference to the drawings, the structure of the embodiments is not limited to the structure shown in the drawings. In addition, the sizes of the components in the drawings are conceptual, and the relative relationship between the sizes of the components is not limited thereto.

[0065] In the present invention, each component may also include a plurality of corresponding substances. In the present invention, when referring to the amount of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it indicates the total amount of the plurality of substances present in the composition.

[0066] In the present invention, multiple types of particles corresponding to each component may be contained. When multiple types of particles corresponding to each component are present in the composition, unless otherwise specified, the particle size of each component represents a value for a mixture of the multiple types of particles present in the composition.

[0067] In the present invention, unless otherwise specified, an alkyl group and an alkylene group include linear, branched, and cyclic groups.

[0068] In the present invention, regarding the organic group, aromatic ring, linking group, alkyl group, alkylene group, aryl group, aralkyl group, alkoxy group, aryloxy group and the like, the hydrogen atom in the group may be substituted by a halogen atom.

[0069] In the present invention, when a compound is represented by a structural formula, the structural formula may be represented by omitting the symbols (C and H) representing the carbon atoms and hydrogen atoms in the hydrocarbon group and / or hydrocarbon chain.

[0070] In the present invention, the "structural unit" of the copolymer or resin has the same meaning as the monomer unit.

[0071] <Electronic Photographic Photoreceptor>

[0072] The electrophotographic photoreceptor (hereinafter, also referred to as “photoreceptor”) according to the present embodiment includes a conductive substrate and a photosensitive layer disposed on the conductive substrate.

[0073] Figure 1This is a partial cross-sectional view schematically showing an example of the layer structure of the photoreceptor according to the present embodiment. Figure 1 The photoreceptor 10A shown has a laminated photosensitive layer. The photoreceptor 10A has a structure in which an undercoat layer 2, a charge generating layer 3, and a charge transporting layer 4 are sequentially laminated on a conductive substrate 1, and the charge generating layer 3 and the charge transporting layer 4 constitute a photosensitive layer 5 (a so-called functionally separated photosensitive layer). The photoreceptor 10A may have an intermediate layer (not shown) between the undercoat layer 2 and the charge generating layer 3. The photoreceptor 10A may have a protective layer (not shown) on the photosensitive layer 5. The undercoat layer 2 may or may not be provided.

[0074] Figure 2 This is a partial cross-sectional view schematically showing another example of the layer structure of the photoreceptor according to the present embodiment. Figure 2 The photoreceptor 10B shown has a single-layer photosensitive layer. The photoreceptor 10B has a structure in which an undercoat layer 2 and a photosensitive layer 5 are sequentially stacked on a conductive substrate 1. The photoreceptor 10B may have an intermediate layer (not shown) between the undercoat layer 2 and the photosensitive layer 5. The photoreceptor 10B may have a protective layer (not shown) on the photosensitive layer 5. The undercoat layer 2 may or may not be provided.

[0075] The photoreceptor according to this embodiment has a charge transport material and a binder resin on the outermost layer and a breaking energy of 10 mJ / mm 3 The above layers have a kinetic friction coefficient of the outer peripheral surface of 0.5 or more and 1.0 or less. The outer peripheral surface refers to the exposed surface of the outermost layer.

[0076] In one embodiment of the photoreceptor, a laminated photosensitive layer including a charge generating layer and a charge transporting layer is provided, and the charge transporting layer is the outermost layer.

[0077] In another embodiment of the photoreceptor, a single-layer photosensitive layer is provided, and the single-layer photosensitive layer is the outermost layer.

[0078] In another example of the embodiment of the photoreceptor, a protective layer is provided on the laminated photosensitive layer or the single-layer photosensitive layer, and the protective layer is the outermost layer.

[0079] Fracture energy of the outermost layer (mJ / mm 3 ) is determined as follows.

[0080] The outermost layer is peeled off from the photoreceptor and cut into a square of 50 mm. The thickness of the outermost layer after peeling is measured. The square is cut into rectangles of 5 mm in width and 25 mm in length to prepare 10 samples. The samples are fixed to the test machine and measured under the following measurement conditions.

[0081] Measuring device: MODEL-1605N (AIKOH ENGINEERING)

[0082] Measurement conditions: load and displacement were measured at a tensile speed of 20 mm / min. Measurement interval was 0.1.

[0083] Number of measurements: 10 times (10 samples)

[0084] The fracture energy was calculated from the integrated value of stress (Pa) and strain until fracture. The measurement results of 10 samples were arithmetic averaged.

[0085] The method for measuring the dynamic friction coefficient of the outer peripheral surface of the photoreceptor is as follows.

[0086] A sapphire probe was brought into contact with the photoreceptor, and the dynamic friction coefficient was calculated from the average value of the friction coefficient when the probe was reciprocated 15 times under the conditions of a moving distance of 10 mm and a moving speed of 10 mm / sec.

[0087] The breaking energy of the outermost layer of the photoreceptor according to this embodiment is 10 mJ / mm 3 The thickness of the conductive film is 0.5 or more and the coefficient of dynamic friction of the outer peripheral surface is 0.5 or more and 1.0 or less, thereby achieving excellent thin line reproducibility and wear resistance.

[0088] Conventionally, it is known that the outermost layer contains a filler having lubricating properties in order to suppress the wear of the photoreceptor. However, the filler present in the outermost layer may cause a decrease in image quality (for example, a decrease in thin line reproducibility).

[0089] As a result of repeated studies, the present inventors have found an outermost layer that is excellent in abrasion resistance regardless of fillers. The photoreceptor according to the present embodiment does not need to contain a filler in the outermost layer, and thus has excellent thin line reproducibility.

[0090] If the fracture energy of the outermost layer of the photoreceptor is less than 10 mJ / mm 3 , which promotes wear and causes uneven density due to increased wear deviation of the photoreceptor. From the perspective of suppressing this phenomenon, the fracture energy of the outermost layer of the photoreceptor is 10 mJ / mm 3 Above, for example, preferably 12 mJ / mm 3 above.

[0091] The upper limit of the breaking energy of the outermost layer of the photoreceptor is, for example, 50 mJ / mm 3 Below, for example, 45mJ / mm 3 Below, for example, 30 mJ / mm 3 the following.

[0092] If the coefficient of kinetic friction of the peripheral surface of the photoreceptor is less than 0.5, the toner cannot be fully scraped off by the cleaning blade and the charging components are contaminated. From the viewpoint of suppressing this phenomenon, the coefficient of kinetic friction of the peripheral surface of the photoreceptor is 0.5 or more, for example, preferably 0.55 or more, more preferably 0.6 or more, and further preferably 0.65 or more.

[0093] If the coefficient of kinetic friction of the outer surface of the photoreceptor exceeds 1.0, the motor load during image formation increases, or a cleaning blade may roll up. To prevent this, the coefficient of kinetic friction of the outer surface of the photoreceptor is 1.0 or less, for example, preferably 0.8 or less.

[0094] From the viewpoint of reducing the wear rate, the coefficient of dynamic friction of the outer peripheral surface of the photoreceptor is divided by the fracture energy (mJ / mm) of the outermost layer of the photoreceptor. 3 ) value (dynamic friction coefficient / fracture energy) is, for example, preferably from 0.01 to 0.10, more preferably from 0.03 to 0.08.

[0095] The fracture energy of the outermost layer of the photoreceptor and the dynamic friction coefficient of the outer peripheral surface of the photoreceptor are controlled by the type and combination of resins constituting the binder resin of the outermost layer and the content of the resin. The form of the binder resin is described below.

[0096] From the viewpoint of abrasion resistance of the outermost layer, the outermost layer of the photoreceptor preferably contains, for example, a polyester resin as a binder resin, and the proportion of the polyester resin in the binder resin is preferably 20 mass % or more and 80 mass % or less.

[0097] If the proportion of polyester resin in the binder resin is 20% by mass or more, wear deviation is reduced. From this viewpoint, the proportion of polyester resin in the binder resin is, for example, more preferably 25% by mass or more, further preferably 30% by mass or more, and further preferably 35% by mass or more.

[0098] When the proportion of the polyester resin in the binder resin is 80% by mass or less, the cleaning property becomes good. From this viewpoint, the proportion of the polyester resin in the binder resin is more preferably 75% by mass or less, for example.

[0099] From the viewpoint of abrasion resistance of the outermost layer, the outermost layer of the photoreceptor preferably contains, for example, polyester resin (1) as a binder resin, and the proportion of polyester resin (1) in the binder resin is preferably 20 mass % to 80 mass %.

[0100] The proportion of the polyester resin (1) in the binder resin is, for example, more preferably 25% by mass or more, further preferably 30% by mass or more, and further preferably 35% by mass or more.

[0101] The proportion of the polyester resin (1) in the binder resin is more preferably, for example, 75% by mass or less.

[0102] The details of the polyester resin (1) will be described later.

[0103] From the viewpoint of reducing wear variation, the ratio of the binder resin in the outermost surface layer of the photoreceptor is, for example, preferably 50% by mass or more, and more preferably 55% by mass or more.

[0104] From the viewpoint of electrical characteristics, the ratio of the binder resin in the outermost surface layer of the photoreceptor is, for example, preferably 70% by mass or less, and more preferably 65% ​​by mass or less.

[0105] The binder resin of the outermost surface layer of the photoreceptor preferably contains two or more resins. The presence of two or more resins forms minute irregularities on the outer peripheral surface, thereby reducing the dynamic friction coefficient of the outer peripheral surface.

[0106] From the viewpoint of abrasion resistance of the outermost layer, the binder resin of the outermost layer of the photoreceptor preferably contains polyester resin and polycarbonate resin, more preferably contains polyarylate resin and polycarbonate resin, and further preferably contains polyester resin (1) and polycarbonate resin.

[0107] As the polycarbonate resin, for example, a polycarbonate resin having a continuous structural unit having an aromatic ring is preferred, and specifically, a polycarbonate resin used in Examples described later is preferred.

[0108] When the outermost layer of the photoreceptor contains polyester resin and polycarbonate resin, the mass ratio of the two resins is, for example, preferably polyester resin:polycarbonate resin = 20:80 to 80:20, more preferably 25:75 to 75:25, further preferably 30:70 to 75:25, and further preferably 35:65 to 75:25.

[0109] When the outermost layer of the photoreceptor contains polyester resin (1) and polycarbonate resin, the mass ratio of the two resins is, for example, preferably polyester resin (1): polycarbonate resin = 20:80 to 80:20, more preferably 25:75 to 75:25, further preferably 30:70 to 75:25, and further preferably 35:65 to 75:25.

[0110] In the photoreceptor according to the present embodiment, for example, the proportion of the fluororesin particles in the outermost layer is preferably 5 mass % or less, more preferably 1 mass % or less, and further preferably 0 mass % (ie, no fluororesin particles are contained).

[0111] In the past, it is known that the outermost layer contains fluororesin particles for the purpose of suppressing the wear of the photoreceptor. However, if the outermost layer contains fluororesin particles, the exposure light (for example, laser beam) that forms the electrostatic latent image in the photoreceptor is scattered, and the reproducibility of fine lines is sometimes reduced. Therefore, the outermost layer of the photoreceptor involved in this embodiment, for example, preferably does not contain fluororesin particles.

[0112] Hereinafter, the polyester resin (1) contained in the outermost layer and each layer of the photoreceptor will be described in detail.

[0113] [Polyester resin (1)]

[0114] The polyester resin as the binder resin of the outermost layer is preferably a polyester resin (1) having at least a dicarboxylic acid unit (A) and a diol unit (B). The polyester resin (1) may contain other dicarboxylic acid units other than the dicarboxylic acid unit (A). The polyester resin (1) may contain other diol units other than the diol unit (B).

[0115] The dicarboxylic acid unit (A) is a structural unit represented by the following formula (A).

[0116] [Chemical formula 1]

[0117] Formula (A)

[0118] In formula (A), Ar A1 and Ar A2 are each independently an aromatic ring which may have a substituent, L A is a single bond or a divalent linking group, n A1 Is 0, 1, or 2.

[0119] Ar A1 The aromatic ring may be a monocyclic ring or a polycyclic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring, and preferably a benzene ring and a naphthalene ring.

[0120] Ar A1 The hydrogen atoms on the aromatic ring of may be substituted by alkyl, aryl, aralkyl, alkoxy, aryloxy, halogen atoms, etc. A1 When the aromatic ring is substituted, the substituent is preferably, for example, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms.

[0121] Ar A2 The aromatic ring may be a monocyclic ring or a polycyclic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring, and preferably a benzene ring and a naphthalene ring.

[0122] Ar A2The hydrogen atoms on the aromatic ring of may be substituted by alkyl, aryl, aralkyl, alkoxy, aryloxy, halogen atoms, etc. A2 When the aromatic ring is substituted, the substituent is preferably, for example, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms.

[0123] When L A When it is a divalent linking group, examples of the divalent linking group include an oxygen atom, a sulfur atom, -C(Ra 1 )(Ra 2 )-. Here, Ra 1 and Ra 2 are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, Ra 1 With Ra 2 They may be bonded to form a cyclic alkyl group.

[0124] Ra 1 and Ra 2 The alkyl group having 1 to 10 carbon atoms may be linear, branched or cyclic. The alkyl group preferably has 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0125] Ra 1 and Ra 2 The aryl group having 6 or more and 12 or less carbon atoms may be a monocyclic or polycyclic ring. The aryl group preferably has 6 or more and 10 or less carbon atoms, and more preferably 6 carbon atoms.

[0126] Ra 1 and Ra 2 The alkyl group in the aralkyl group having 7 to 20 carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms in the aralkyl group having 7 to 20 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2.

[0127] Ra 1 and Ra 2 The aryl group in the aralkyl group having 7 to 20 carbon atoms may be a monocyclic or polycyclic ring. The aryl group preferably has 6 to 10 carbon atoms, and more preferably 6 carbon atoms.

[0128] The dicarboxylic acid unit (A) preferably includes at least one selected from the group consisting of a dicarboxylic acid unit (A1) represented by the following formula (A1), a dicarboxylic acid unit (A2) represented by the formula (A2), a dicarboxylic acid unit (A3) represented by the formula (A3), and a dicarboxylic acid unit (A4) represented by the formula (A4). The dicarboxylic acid unit (A) more preferably includes at least one selected from the group consisting of a dicarboxylic acid unit (A2), a dicarboxylic acid unit (A3), and a dicarboxylic acid unit (A4), and further preferably includes a dicarboxylic acid unit (A2).

[0129] [Chemical formula 2]

[0130] Formula (A1)

[0131] In formula (A1), n 101 is an integer greater than or equal to 0 and less than or equal to 4, n 101 Ra 101 Each independently represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0132] n 101 For example, it is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0133] [Chemical formula 3]

[0134] Formula (A2)

[0135] In formula (A2), n 201 and n 202 are each independently an integer of 0 to 4, and n 201 Ra 201 and n 202 Ra 202 Each independently represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0136] n 201 For example, it is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0137] n 202 For example, it is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0138] [Chemical formula 4]

[0139] Formula (A3)

[0140] In formula (A3), n 301 and n302 are each independently an integer of 0 to 4, and n 301 Ra 301 and n 302 Ra 302 Each independently represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0141] n 301 For example, it is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0142] n 302 For example, it is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0143] [Chemical formula 5]

[0144] Formula (A4)

[0145] In formula (A4), n 401 is an integer greater than or equal to 0 and less than or equal to 6, n 401 Ra 401 Each independently represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0146] n 401 For example, it is preferably an integer of 0 or more and 4 or less, more preferably 0, 1 or 2, and still more preferably 0.

[0147] Ra of formula (A1) 101 , Ra of formula (A2) 201 and Ra 202 , Ra of formula (A3) 301 and Ra 302 And Ra of formula (A4) 401 The specific method and preferred method are the same, so in the following, Ra 101 , Ra 201 , Ra 202 , Ra 301 , Ra 302 and Ra 401 They are collectively referred to as “Ra” for explanation.

[0148] The alkyl group having 1 to 10 carbon atoms represented by Ra may be linear, branched, or cyclic. The alkyl group preferably has 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0149] Examples of the linear alkyl group having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl.

[0150] Examples of the branched alkyl group having 3 to 10 carbon atoms include isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, sec-decyl, and tert-decyl.

[0151] Examples of the cyclic alkyl group having 3 to 10 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and polycyclic (e.g., bicyclic, tricyclic, spirocyclic) alkyl groups in which these monocyclic alkyl groups are linked.

[0152] The aryl group having 6 or more and 12 or less carbon atoms represented by Ra may be a monocyclic or polycyclic group. The aryl group preferably has 6 or more and 10 or less carbon atoms, and more preferably 6 carbon atoms.

[0153] Examples of the aryl group having 6 to 12 carbon atoms include phenyl, biphenyl, 1-naphthyl, and 2-naphthyl.

[0154] The alkyl group in the alkoxy group having 1 to 6 carbon atoms represented by Ra may be any of linear, branched, and cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2.

[0155] Examples of the linear alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, and an n-hexyloxy group.

[0156] Examples of the branched alkoxy group having 3 to 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy and tert-hexyloxy.

[0157] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, and cyclohexyloxy.

[0158] Hereinafter, dicarboxylic acid units (A1-1) to (A1-9) are shown as specific examples of the dicarboxylic acid unit (A1). The dicarboxylic acid unit (A1) is not limited thereto.

[0159] [Chemical formula 6]

[0160]

[0161] Hereinafter, dicarboxylic acid units (A2-1) to (A2-3) are shown as specific examples of the dicarboxylic acid units (A2), but the dicarboxylic acid units (A2) are not limited thereto.

[0162] [Chemical formula 7]

[0163]

[0164] Hereinafter, dicarboxylic acid units (A3-1) to (A3-2) are shown as specific examples of the dicarboxylic acid unit (A3). The dicarboxylic acid unit (A3) is not limited thereto.

[0165] [Chemical formula 8]

[0166]

[0167] Hereinafter, dicarboxylic acid units (A4-1) to (A4-3) are shown as specific examples of the dicarboxylic acid unit (A4). The dicarboxylic acid unit (A4) is not limited thereto.

[0168] [Chemical formula 9]

[0169]

[0170] The dicarboxylic acid unit (A) preferably contains at least one selected from the group consisting of (A1-1), (A1-7), (A2-3), (A3-2) and (A4-3) as the specific examples above, more preferably contains at least one selected from the group consisting of (A2-3), (A3-2) and (A4-3), and further preferably contains at least (A2-3).

[0171] The mass ratio of the total of the dicarboxylic acid units (A1) to (A4) in the polyester resin (1) is, for example, preferably 15 mass % or more and 60 mass % or less.

[0172] When the total mass ratio of the dicarboxylic acid units (A1) to (A4) is 15 mass % or more, the wear resistance of the outermost layer is good. From this viewpoint, the total mass ratio of the dicarboxylic acid units (A1) to (A4) is, for example, more preferably 20 mass % or more, and further preferably 25 mass % or more.

[0173] When the total mass ratio of the dicarboxylic acid units (A1) to (A4) is 60 mass % or less, peeling of the outermost layer can be suppressed. From this viewpoint, the total mass ratio of the dicarboxylic acid units (A1) to (A4) is, for example, more preferably 55 mass % or less, and further preferably 50 mass % or less.

[0174] The dicarboxylic acid units (A1) to (A4) contained in the polyester resin (1) may be one type or two or more types.

[0175] Examples of other dicarboxylic acid units (A) other than the dicarboxylic acid units (A1) to (A4) include aliphatic dicarboxylic acid (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid) units, alicyclic dicarboxylic acid (e.g., cyclohexane dicarboxylic acid) units, and lower (e.g., carbon number of 1 to 5) alkyl ester units thereof. The dicarboxylic acid units contained in the polyester resin (1) may be one type or two or more types.

[0176] The dicarboxylic acid unit (A) contained in the polyester resin (1) may be one kind or two or more kinds.

[0177] The diol unit (B) is a structural unit represented by the following formula (B).

[0178] [Chemical formula 10]

[0179] Formula (B)

[0180] In formula (B), Ar B1 and Ar B2 are each independently an aromatic ring which may have a substituent, L B is a single bond, oxygen atom, sulfur atom or -C(Rb 1 )(Rb 2 )-,n B1 is 0, 1 or 2. 1 and Rb 2 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and Rb 1 With Rb 2 They may be bonded to form a cyclic alkyl group.

[0181] Ar B1 The aromatic ring may be a monocyclic ring or a polycyclic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring, and preferably a benzene ring and a naphthalene ring.

[0182] Ar B1 The hydrogen atoms on the aromatic ring of may be substituted by alkyl, aryl, aralkyl, alkoxy, aryloxy, halogen atoms, etc. B1 When the aromatic ring is substituted, the substituent is preferably, for example, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms.

[0183] Ar B2 The aromatic ring may be a monocyclic ring or a polycyclic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring, and preferably a benzene ring and a naphthalene ring.

[0184] Ar B2 The hydrogen atoms on the aromatic ring of may be substituted by alkyl, aryl, aralkyl, alkoxy, aryloxy, halogen atoms, etc. B2 When the aromatic ring is substituted, the substituent is preferably, for example, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms.

[0185] R 1 and Rb 2 The alkyl group having 1 to 20 carbon atoms may be linear, branched or cyclic. The alkyl group preferably has 1 to 18 carbon atoms, more preferably 1 to 14 carbon atoms, and even more preferably 1 to 10 carbon atoms.

[0186] R 1 and Rb 2 The aryl group having 6 or more and 12 or less carbon atoms may be a monocyclic or polycyclic ring. The aryl group preferably has 6 or more and 10 or less carbon atoms, and more preferably 6 carbon atoms.

[0187] R 1 and Rb 2 The alkyl group in the aralkyl group having 7 to 20 carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms in the aralkyl group having 7 to 20 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2.

[0188] R 1 and Rb 2 The aryl group in the aralkyl group having 7 to 20 carbon atoms may be a monocyclic or polycyclic ring. The aryl group preferably has 6 to 10 carbon atoms, and more preferably 6 carbon atoms.

[0189] The diol unit (B) preferably includes at least one selected from the group consisting of a diol unit (B1) represented by the following formula (B1), a diol unit (B2) represented by the formula (B2), a diol unit (B3) represented by the formula (B3), a diol unit (B4) represented by the formula (B4), a diol unit (B5) represented by the formula (B5), a diol unit (B6) represented by the formula (B6), a diol unit (B7) represented by the formula (B7), and a diol unit (B8) represented by the formula (B8).

[0190] The diol unit (B) more preferably includes at least one selected from the group consisting of a diol unit (B1) represented by the following formula (B1), a diol unit (B2) represented by the formula (B2), a diol unit (B4) represented by the formula (B4), a diol unit (B5) represented by the formula (B5), and a diol unit (B6) represented by the formula (B6).

[0191] It is more preferred that the polyol contains at least one selected from the group consisting of a diol unit (B1) represented by the following formula (B1), a diol unit (B2) represented by the formula (B2), a diol unit (B5) represented by the formula (B5), and a diol unit (B6) represented by the formula (B6).

[0192] It is further preferred that the polyol contains at least one selected from the group consisting of a diol unit (B1) represented by the following formula (B1), a diol unit (B2) represented by the following formula (B2), and a diol unit (B6) represented by the following formula (B6).

[0193] Most preferably, the polyol contains at least one selected from the group consisting of a diol unit (B1) represented by the following formula (B1) and a diol unit (B2) represented by the following formula (B2).

[0194] [Chemical formula 11]

[0195] Formula (B1)

[0196] In formula (B1), Rb 101 is a branched alkyl group having 4 to 20 carbon atoms, Rb 201 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 401 , Rb 501 , Rb 801 and Rb 901 Each of them is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0197] R 101 The branched alkyl group having 4 to 20 carbon atoms preferably has 4 to 16 carbon atoms, more preferably 4 to 12 carbon atoms, and even more preferably 4 to 8 carbon atoms. 101 Specific examples of include isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, sec-decyl, tert-decyl, isododecyl, sec-dodecyl, tert-dodecyl, tert-tetradecyl, and tert-pentadecyl.

[0198] [Chemical formula 12]

[0199] Formula (B2)

[0200] In formula (B2), Rb 102 is a straight-chain alkyl group having 4 to 20 carbon atoms, Rb 202 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 402 , Rb 502 , Rb 802 and Rb 902 Each of them is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0201] R 102 The carbon number of the linear alkyl group having 4 or more and 20 or less is, for example, preferably 4 or more and 16 or less, more preferably 4 or more and 12 or less, and even more preferably 4 or more and 8 or less. 102 Specific examples include n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, tridecyl, n-tetradecyl, n-pentadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, and n-eicosyl.

[0202] [Chemical formula 13]

[0203] Formula (B3)

[0204] In formula (B3), Rb 113 and Rb 213 are each independently a hydrogen atom, a linear alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, d is an integer of 7 to 15, Rb 403 , Rb 503 , Rb 803 and Rb 903 Each of them is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0205] R 113 and Rb 213 The carbon number of the linear alkyl group having 1 to 3 carbon atoms is preferably 1 or 2, and more preferably 1. Specific examples of the group include a methyl group, an ethyl group, and an n-propyl group.

[0206] R 113 and Rb 213The alkyl group in the alkoxy group having 1 to 4 carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 4 carbon atoms is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. Specific examples of the group include methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclopropyloxy, cyclobutyloxy, and the like.

[0207] As Rb 113 and Rb 213 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0208] [Chemical formula 14]

[0209] Formula (B4)

[0210] In formula (B4), Rb 104 and Rb 204 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 404 , Rb 504 , Rb 804 and Rb 904 Each of them is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0211] R 104 The alkyl group having 1 to 3 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 or 2, more preferably 1. 104 Specific examples of include methyl, ethyl, n-propyl, isopropyl and cyclopropyl.

[0212] [Chemical formula 15]

[0213] Formula (B5)

[0214] In formula (B5), Ar 105 is an aryl group having 6 to 12 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, Rb 205 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 405 , Rb 505 , Rb 805 and Rb 905 Each of them is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0215] Ar105 The aryl group having 6 or more and 12 or less carbon atoms may be a monocyclic or polycyclic ring. The aryl group preferably has 6 or more and 10 or less carbon atoms, and more preferably 6 carbon atoms.

[0216] Ar 105 The alkyl group in the aralkyl group having 7 to 20 carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms in the aralkyl group having 7 to 20 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2. 105 The aryl group in the aralkyl group having 7 to 20 carbon atoms may be either a monocyclic or polycyclic group. The number of carbon atoms of the aryl group is preferably, for example, 6 to 10, more preferably 6. Examples of the aralkyl group having 7 to 20 carbon atoms include benzyl, phenylethyl, phenylpropyl, 4-phenylbutyl, phenylpentyl, phenylhexyl, phenylheptyl, phenyloctyl, phenylnonyl, naphthylmethyl, naphthylethyl, anthracenylmethyl, and phenyl-cyclopentylmethyl.

[0217] [Chemical formula 16]

[0218] Formula (B6)

[0219] In formula (B6), Rb 116 and Rb 216 are each independently a hydrogen atom, a linear alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, e is an integer of 4 to 6, Rb 406 , Rb 506 , Rb 806 and Rb 906 Each of them is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0220] R 116 and Rb 216 The carbon number of the linear alkyl group having 1 to 3 carbon atoms is preferably 1 or 2, and more preferably 1. Specific examples of the group include a methyl group, an ethyl group, and an n-propyl group.

[0221] R 116 and Rb 216The alkyl group in the alkoxy group having 1 to 4 carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 4 carbon atoms is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. Specific examples of the group include methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclopropyloxy, cyclobutyloxy, and the like.

[0222] As Rb 116 and Rb 216 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0223] [Chemical formula 17]

[0224] Formula (B7)

[0225] In formula (B7), Rb 407 , Rb 507 , Rb 807 and Rb 907 Each of them is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0226] [Chemical formula 18]

[0227] Formula (B8)

[0228] In formula (B8), Rb 408 , Rb 508 , Rb 808 and Rb 908 Each of them is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0229] Rb in formula (B1) 201 , Rb of formula (B2) 202 , Rb of formula (B4) 204 And Rb in formula (B5) 205 The specific method and preferred method are the same, so below, Rb 201 , Rb 202 , Rb 204 and Rb 205 Collectively referred to as "Rb 200 " to explain.

[0230] R 200The alkyl group having 1 to 3 carbon atoms may be linear, branched, or cyclic. The alkyl group preferably has 1 or 2 carbon atoms, and more preferably 1 carbon atom.

[0231] Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and a cyclopropyl group.

[0232] Rb in formula (B1) 401 , Rb of formula (B2) 402 , Rb of formula (B3) 403 , Rb of formula (B4) 404 , Rb of formula (B5) 405 , Rb of formula (B6) 406 , Rb of formula (B7) 407 And Rb in formula (B8) 408 The specific method and preferred method are the same, so below, Rb 401 , Rb 402 , Rb 403 , Rb 404 , Rb 405 , Rb 406 , Rb 407 and Rb 408 Collectively referred to as "Rb 400 " to explain.

[0233] R 400 The alkyl group having 1 to 4 carbon atoms may be linear, branched or cyclic. The alkyl group preferably has 1 to 3 carbon atoms, more preferably 1 or 2, and even more preferably 1 carbon atom.

[0234] Examples of the linear alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group.

[0235] Examples of the branched alkyl group having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl and tert-butyl.

[0236] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0237] R 400 The alkyl group in the alkoxy group having 1 to 6 carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2.

[0238] Examples of the linear alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, and an n-hexyloxy group.

[0239] Examples of the branched alkoxy group having 3 to 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy and tert-hexyloxy.

[0240] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, and cyclohexyloxy.

[0241] As Rb 400 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0242] Rb in formula (B1) 501 , Rb of formula (B2) 502 , Rb of formula (B3) 503 , Rb of formula (B4) 504 , Rb of formula (B5) 505 , Rb of formula (B6) 506 , Rb of formula (B7) 507 And Rb in formula (B8) 508 The specific method and preferred method are the same, so below, Rb 501 , Rb 502 , Rb 503 , Rb 504 , Rb 505 , Rb 506 , Rb 507 and Rb 508 Collectively referred to as "Rb 500 " to explain.

[0243] R 500 The alkyl group having 1 to 4 carbon atoms may be linear, branched or cyclic. The alkyl group preferably has 1 to 3 carbon atoms, more preferably 1 or 2, and even more preferably 1 carbon atom.

[0244] Examples of the linear alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group.

[0245] Examples of the branched alkyl group having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl and tert-butyl.

[0246] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0247] R 500The alkyl group in the alkoxy group having 1 to 6 carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2.

[0248] Examples of the linear alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, and an n-hexyloxy group.

[0249] Examples of the branched alkoxy group having 3 to 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy and tert-hexyloxy.

[0250] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, and cyclohexyloxy.

[0251] As Rb 500 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0252] Rb in formula (B1) 801 , Rb of formula (B2) 802 , Rb of formula (B3) 803 , Rb of formula (B4) 804 , Rb of formula (B5) 805 , Rb of formula (B6) 806 , Rb of formula (B7) 807 And Rb in formula (B8) 808 The specific method and preferred method are the same, so below, Rb 801 , Rb 802 , Rb 803 , Rb 804 , Rb 805 , Rb 806 , Rb 807 and Rb 808 Collectively referred to as "Rb 800 " to explain.

[0253] R 800 The alkyl group having 1 to 4 carbon atoms may be linear, branched or cyclic. The alkyl group preferably has 1 to 3 carbon atoms, more preferably 1 or 2, and even more preferably 1 carbon atom.

[0254] Examples of the linear alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group.

[0255] Examples of the branched alkyl group having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl and tert-butyl.

[0256] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0257] R 800 The alkyl group in the alkoxy group having 1 to 6 carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2.

[0258] Examples of the linear alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, and an n-hexyloxy group.

[0259] Examples of the branched alkoxy group having 3 to 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy and tert-hexyloxy.

[0260] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, and cyclohexyloxy.

[0261] As Rb 800 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0262] Rb in formula (B1) 901 , Rb of formula (B2) 902 , Rb of formula (B3) 903 , Rb of formula (B4) 904 , Rb of formula (B5) 905 , Rb of formula (B6) 906 , Rb of formula (B7) 907 And Rb in formula (B8) 908 The specific method and preferred method are the same, so below, Rb 901 , Rb 902 , Rb 903 , Rb 904 , Rb 905 , Rb 906 , Rb 907 and Rb 908 Collectively referred to as "Rb 900 " to explain.

[0263] R 900The alkyl group having 1 to 4 carbon atoms may be linear, branched or cyclic. The alkyl group preferably has 1 to 3 carbon atoms, more preferably 1 or 2, and even more preferably 1 carbon atom.

[0264] Examples of the linear alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group.

[0265] Examples of the branched alkyl group having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl and tert-butyl.

[0266] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0267] R 900 The alkyl group in the alkoxy group having 1 to 6 carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms in the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2.

[0268] Examples of the linear alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, and an n-hexyloxy group.

[0269] Examples of the branched alkoxy group having 3 to 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy and tert-hexyloxy.

[0270] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, and cyclohexyloxy.

[0271] As Rb 900 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0272] Hereinafter, diol units (B1-1) to (B1-6) are shown as specific examples of the diol unit (B1), but the diol unit (B1) is not limited thereto.

[0273] [Chemical formula 19]

[0274]

[0275] Hereinafter, diol units (B2-1) to (B2-11) are shown as specific examples of the diol unit (B2), but the diol unit (B2) is not limited thereto.

[0276] [Chemical formula 20]

[0277]

[0278] Specific examples of the diol unit (B3) include diol units (B3-1) to (B3-4), but the diol unit (B3) is not limited thereto.

[0279] [Chemical formula 21]

[0280]

[0281] Specific examples of the diol unit (B4) include diol units (B4-1) to (B4-7), but the diol unit (B4) is not limited thereto.

[0282] [Chemical formula 22]

[0283]

[0284] Specific examples of the diol unit (B5) include diol units (B5-1) to (B5-6), but the diol unit (B5) is not limited thereto.

[0285] [Chemical formula 23]

[0286]

[0287] Specific examples of the diol unit (B6) include diol units (B6-1) to (B6-4), but the diol unit (B6) is not limited thereto.

[0288] [Chemical formula 24]

[0289]

[0290] Hereinafter, diol units (B7-1) to (B7-3) are shown as specific examples of the diol unit (B7), but the diol unit (B7) is not limited thereto.

[0291] [Chemical formula 25]

[0292]

[0293] Specific examples of the diol unit (B8) include diol units (B8-1) to (B8-3), but the diol unit (B8) is not limited thereto.

[0294] [Chemical formula 26]

[0295]

[0296] The diol unit (B) contained in the polyester resin (1) may be one kind or two or more kinds.

[0297] The mass ratio of the diol unit (B) in the polyester resin (1) is preferably, for example, 25 mass % or more and 80 mass % or less.

[0298] When the mass ratio of the diol unit (B) is 25 mass % or more, peeling of the outermost layer can be suppressed. From this viewpoint, the mass ratio of the diol unit (B) is, for example, more preferably 30 mass % or more, and further preferably 35 mass % or more.

[0299] If the mass ratio of the diol unit (B) is 80 mass % or less, the solubility in the coating liquid for forming the outermost layer can be maintained and the wear resistance can be improved. From this viewpoint, the mass ratio of the diol unit (B) is, for example, more preferably 75 mass % or less, and further preferably 70 mass % or less.

[0300] Examples of other diol units other than the diol unit (B) include aliphatic diol (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol) units and alicyclic diol (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A) units. The diol units contained in the polyester resin (1) may be one type or two or more types.

[0301] The ends of the polyester resin (1) may be capped or modified by an end-capping agent or a molecular weight modifier used in the production. Examples of the end-capping agent or molecular weight modifier include monophenols, monoacid chlorides, monoalcohols, and monocarboxylic acids.

[0302] Examples of the monohydric phenol include phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-propylphenol, m-propylphenol, p-propylphenol, o-tert-butylphenol, m-tert-butylphenol, p-tert-butylphenol, pentylphenol, hexylphenol, octylphenol, nonylphenol, 2,6-dimethylphenol derivatives, 2-methylphenol derivatives, o-phenylphenol, m-phenylphenol, p-phenylphenol, o-methoxyphenol, Phenol, m-methoxyphenol, p-methoxyphenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, 2-phenyl-2-(4-hydroxyphenyl)propane, 2-phenyl-2-(2-hydroxyphenyl)propane, 2-phenyl-2-(3-hydroxyphenyl)propane.

[0303] Examples of the monoacid chloride include monofunctional acid halides such as benzoyl chloride, benzoyl chloride, methanesulfonyl chloride, phenyl chloroformate, acetyl chloride, butyryl chloride, octanoyl chloride, benzenesulfonyl chloride, benzenesulfenyl chloride, sulfenyl chloride, phenylphosphonyl chloride, and substitution products thereof.

[0304] Examples of the monohydric alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, pentanol, hexanol, dodecanol, stearyl alcohol, benzyl alcohol, and phenethyl alcohol.

[0305] Examples of the monocarboxylic acid include acetic acid, propionic acid, octanoic acid, cyclohexanecarboxylic acid, benzoic acid, methylbenzoic acid, phenylacetic acid, p-tert-butylbenzoic acid, and p-methoxyphenylacetic acid.

[0306] The weight average molecular weight of the polyester resin (1) is, for example, preferably 30,000 to 300,000, more preferably 40,000 to 250,000, and even more preferably 50,000 to 200,000.

[0307] The molecular weight of the polyester resin (1) is a molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography). Tetrahydrofuran is used as an eluent in GPC.

[0308] The polyester resin (1) is obtained by polycondensing a monomer imparting a dicarboxylic acid unit (A) and a monomer imparting a diol unit (B), and other monomers as required, by a conventional method. Examples of the polycondensation method of the monomers include interfacial polymerization, solution polymerization, and melt polymerization. The interfacial polymerization method is a polymerization method for obtaining a polyester by mixing a dibasic carboxylic acid halide dissolved in an organic solvent incompatible with water and a diol dissolved in an alkaline aqueous solution. Examples of literature related to the interfacial polymerization method include WMEARECKSON, J.Poly.Sci., XL399, 1959, Special Publication No. 40-1959, and the like. Compared with the solution polymerization method, the interfacial polymerization method has a fast reaction, so the hydrolysis of the dibasic carboxylic acid halide can be suppressed, and as a result, a high molecular weight polyester resin can be obtained.

[0309] [Conductive substrate]

[0310] As the conductive substrate, for example, metal plates, metal drums, and metal belts containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.) can be cited. In addition, as the conductive substrate, for example, conductive compounds (such as conductive polymers, indium oxide, etc.); paper coated, vapor-deposited, or laminated with metals (such as aluminum, palladium, gold, etc.) or alloys; resin films; belts, etc. Here, "conductive" means that the volume resistivity is less than 1×10 13 Ω·cm.

[0311] When the electrophotographic photoreceptor is used in a laser printer, the surface of the conductive substrate is preferably roughened to 0.04 μm or more and 0.5 μm or less in terms of center line average roughness Ra for the purpose of suppressing interference fringes generated when irradiating a laser beam. When incoherent light is used as a light source, roughening to prevent interference fringes is not particularly necessary, but the generation of defects caused by the unevenness of the conductive substrate surface is suppressed, so it is suitable for a longer life.

[0312] Examples of the roughening method include wet grinding in which an abrasive is suspended in water and sprayed onto the conductive substrate, centerless grinding in which the conductive substrate is pressed against a rotating grinding wheel and continuously ground, and anodizing.

[0313] As a method of roughening, there is also a method in which, without roughening the surface of the conductive substrate, conductive or semiconductive powder is dispersed in a resin to form a layer on the surface of the conductive substrate, and roughening is performed by particles dispersed in the layer.

[0314] The roughening treatment based on anodization is to use a metal (e.g., aluminum) conductive substrate as an anode and perform anodization in an electrolyte solution, thereby forming an oxide film on the surface of the conductive substrate. As an electrolyte solution, for example, sulfuric acid solution, oxalic acid solution, etc. can be cited. However, the porous anodized film formed by anodization has chemical activity in its original state, is easily contaminated, and the resistance change caused by the environment is also large. Therefore, for example, it is preferred that the porous anodized film is blocked by the volume expansion caused by water and reaction in pressurized water vapor or boiling water (metal salts such as nickel can be added) to change the micropores of the oxide film to the sealing treatment of a more stable hydrated oxide.

[0315] The film thickness of the anodized film is preferably, for example, 0.3 μm or more and 15 μm or less. When the film thickness is within the above range, the barrier property against injection tends to function and the increase in residual potential due to repeated use tends to be suppressed.

[0316] The conductive substrate may be subjected to a treatment using an acidic treatment liquid or a boehmite treatment.

[0317] The treatment based on the acidic treatment liquid is implemented, for example, in the following manner. First, an acidic treatment liquid containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is, for example, in the range of 10 mass % or more and 11 mass % or less for phosphoric acid, in the range of 3 mass % or more and 5 mass % or less for chromic acid, and in the range of 0.5 mass % or more and 2 mass % or less for hydrofluoric acid, and the concentration of the total amount of these acids is, for example, preferably in the range of 13.5 mass % or more and 18 mass % or less. The treatment temperature is, for example, preferably in the range of 42° C. or more and 48° C. or less. The film thickness of the film is, for example, preferably in the range of 0.3 μm or more and 15 μm or less.

[0318] The boehmite treatment is carried out, for example, by immersing in pure water at 90°C to 100°C for 5 to 60 minutes or contacting in heated water vapor at 90°C to 120°C for 5 to 60 minutes. The film thickness of the film is preferably 0.1 μm to 5 μm. An anodizing treatment can be further performed using an electrolyte solution with low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, or citrate.

[0319] [Undercoat]

[0320] The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

[0321] Examples of inorganic particles include powder resistance (volume resistivity) of 1×10 2 Ω·cm or more and 1×10 11 Inorganic particles with a particle size of less than Ω·cm.

[0322] Among them, as the inorganic particles having the above resistance value, for example, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles are preferred, and zinc oxide particles are particularly preferred.

[0323] The specific surface area of ​​the inorganic particles based on the BET method is preferably 10 m 2 / g or above.

[0324] The volume average particle diameter of the inorganic particles is, for example, preferably 50 nm or more and 2000 nm or less (for example, preferably 60 nm or more and 1000 nm or less).

[0325] The content of the inorganic particles is, for example, preferably 10% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 80% by mass or less, based on the binder resin.

[0326] The inorganic particles may be subjected to surface treatment. Two or more inorganic particles having different surface treatments or particles having different particle sizes may be used in combination.

[0327] Examples of the surface treatment agent include silane coupling agents, titanate coupling agents, aluminum coupling agents, surfactants, etc. In particular, for example, a silane coupling agent is preferred, and a silane coupling agent having an amino group is more preferred.

[0328] Examples of the silane coupling agent having an amino group include, but are not limited to, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane.

[0329] Silane coupling agents can be mixed and used in two or more ways. For example, silane coupling agents with amino groups can be used in combination with other silane coupling agents. As other silane coupling agents, for example, vinyl trimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyl trimethoxysilane, 3-glycidoxypropyl trimethoxysilane, vinyl triacetoxysilane, 3-mercaptopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, N-2- (aminoethyl) -3-aminopropyl trimethoxysilane, N-2- (aminoethyl) -3-aminopropyl methyl dimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyl triethoxysilane, 3-chloropropyl trimethoxysilane, etc. can be cited, but it is not limited thereto.

[0330] The surface treatment method using the surface treatment agent may be any method as long as it is a known method, and may be either a dry method or a wet method.

[0331] The treatment amount of the surface treatment agent is preferably, for example, 0.5% by mass or more and 10% by mass or less relative to the inorganic particles.

[0332] Here, from the viewpoint of improving the long-term stability of electrical characteristics and carrier blocking properties, the undercoat layer preferably contains an electron accepting compound (acceptor compound) together with inorganic particles, for example.

[0333] As electron accepting compounds, for example, there can be mentioned quinone compounds such as chloranil and tetrabromobenzoquinone; tetracyanobenzoquinone dimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone; oxadiazole compounds such as 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, 2,5-bis(4-naphthyl)-1,3,4-oxadiazole, and 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole; xanthone compounds; thiophene compounds; diphenoquinone compounds such as 3,3',5,5'-tetra-tert-butyldiphenoquinone; benzophenone compounds; and other electron transporting substances.

[0334] In particular, the electron accepting compound is preferably a compound having an anthraquinone structure. The compound having an anthraquinone structure is preferably a hydroxyanthraquinone compound, an aminoanthraquinone compound, an aminohydroxyanthraquinone compound, and more specifically, anthraquinone, alizarin, quinizarin, anthraquinone, purpurin, and the like.

[0335] The electron accepting compound may be contained in the undercoat layer in a dispersed state together with the inorganic particles, or may be contained in the undercoat layer in a state of being attached to the surfaces of the inorganic particles.

[0336] Examples of a method for attaching the electron accepting compound to the surface of the inorganic particles include a dry method and a wet method.

[0337] The dry method is, for example, a method in which an electron accepting compound or an electron accepting compound dissolved in an organic solvent is directly added dropwise while stirring the inorganic particles by a mixer with a large shear force, and the electron accepting compound is sprayed together with dry air or nitrogen to attach the electron accepting compound to the surface of the inorganic particles. When the electron accepting compound is added dropwise or sprayed, for example, it can be done at a temperature below the boiling point of the solvent. After the electron accepting compound is added dropwise or sprayed, sintering can also be performed at a condition of 100°C or above. There is no particular limitation on the sintering temperature and time as long as the electrophotographic properties can be obtained.

[0338] The wet method is, for example, a method in which inorganic particles are dispersed in a solvent by stirring, ultrasonic waves, a sand mill, a grinder, a ball mill, etc., and after adding an electron accepting compound and stirring or dispersing, the solvent is removed to attach the electron accepting compound to the surface of the inorganic particles. The solvent removal method is, for example, to remove the solvent by filtering or distilling. After removing the solvent, sintering can also be performed at a condition of 100°C or above. Sintering is not particularly limited as long as the temperature and time are such that electronic photographic properties can be obtained. In the wet method, the water content of the inorganic particles can be removed before adding the electron accepting compound. As examples thereof, a method of removing the water content in the solvent while stirring and heating the water content, and a method of removing the water content by azeotropic reaction with the solvent can be cited.

[0339] The electron accepting compound may be attached before or after the inorganic particles are surface treated with a surface treatment agent, or the electron accepting compound may be attached and the surface treated with a surface treatment agent may be simultaneously performed.

[0340] The content of the electron accepting compound may be, for example, 0.01 mass % to 20 mass % inclusive, and preferably 0.01 mass % to 10 mass % inclusive, based on the inorganic particles.

[0341] Examples of the binder resin used in the lower coating layer include acetal resins (e.g., polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, unsaturated polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, urea resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins, alkyd resins, epoxy resins and other well-known polymer compounds; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; organic titanium compounds; silane coupling agents and other well-known materials.

[0342] Examples of the binder resin used in the undercoat layer include a charge transporting resin having a charge transporting group, and a conductive resin (for example, polyaniline).

[0343] Among them, the binding resin used in the lower coating layer is preferably a resin that is insoluble in the coating solvent in the upper layer, and is particularly preferably a resin obtained by reacting at least one resin selected from the group consisting of thermosetting resins such as urea resin, phenolic resin, phenol-formaldehyde resin, melamine resin, urethane resin, unsaturated polyester resin, alkyd resin, epoxy resin, polyamide resin, polyester resin, polyether resin, methacrylic resin, acrylic resin, polyvinyl alcohol resin and polyvinyl acetal resin with a curing agent.

[0344] When two or more of these binder resins are used in combination, the mixing ratio is set as necessary.

[0345] In order to improve electrical characteristics, improve environmental stability, and improve image quality, various additives may be included in the undercoat layer.

[0346] As additives, there can be mentioned known materials such as polycyclic condensation type, azo type and other electron transporting pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents, etc. As mentioned above, silane coupling agents are used for surface treatment of inorganic particles, but can also be added to the undercoat layer as an additive.

[0347] Examples of the silane coupling agent as an additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane.

[0348] Examples of the zirconium chelate compound include zirconium butoxide, zirconium ethyl acetoacetate, zirconium triethanolamine, zirconium acetylacetonate butoxide, zirconium ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, zirconium methacrylate butoxide, zirconium stearate butoxide, and zirconium isostearate butoxide.

[0349] Examples of the titanium chelate compound include tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate, titanium polyacetylacetonate, titanium octanediol, ammonium lactate titanium, titanium lactate, ethyl lactate titanium, triethanolamine titanium, and polyhydroxystearate titanium.

[0350] Examples of the aluminum chelate compound include aluminum isopropoxide, monobutoxyaluminum diisopropoxide, aluminum butoxide, diethyl acetoacetate aluminum diisopropoxide, and tris(ethyl acetoacetate)aluminum.

[0351] These additives may be used alone or in the form of a mixture or polycondensate of a plurality of compounds.

[0352] The undercoat layer may have a Vickers hardness of 35 or more, for example.

[0353] In order to suppress interference moire images, the surface roughness (ten-point average roughness) of the undercoat layer is preferably adjusted to, for example, 1 / (4n) (n is the refractive index of the upper layer) to 1 / 2 of the exposure laser wavelength λ used.

[0354] In order to adjust the surface roughness, resin particles or the like may be added to the undercoat layer. Examples of the resin particles include silicone resin particles and cross-linked polymethacrylate methyl resin particles. In addition, in order to adjust the surface roughness, the surface of the undercoat layer may be ground. Examples of the grinding method include polishing, sandblasting, wet grinding, grinding, and the like.

[0355] The formation of the undercoat layer is not particularly limited and can be performed by a known formation method. For example, the undercoat layer can be formed by forming a coating film of an undercoat layer-forming coating liquid prepared by adding the above-mentioned components to a solvent, drying the coating film, and heating as necessary.

[0356] Examples of the solvent used for preparing the coating solution for forming an undercoat layer include known organic solvents such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, ketone alcohol solvents, ether solvents, and ester solvents.

[0357] Specific examples of these solvents include common organic solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, dichloromethane, chloroform, chlorobenzene, and toluene.

[0358] Examples of a method for dispersing the inorganic particles when preparing the coating liquid for forming an undercoat layer include known methods such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

[0359] Examples of a method for applying the coating liquid for forming an undercoat layer onto the conductive substrate include common methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0360] The thickness of the undercoat layer is preferably set to, for example, 15 μm or more, and more preferably within a range of 20 μm or more and 50 μm or less.

[0361] [Middle layer]

[0362] The intermediate layer is, for example, a layer containing a resin. Examples of the resin used in the intermediate layer include acetal resins (e.g., polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenol-formaldehyde resins, melamine resins and other polymer compounds.

[0363] The intermediate layer may be a layer containing an organic metal compound. Examples of the organic metal compound used in the intermediate layer include organic metal compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.

[0364] The compounds used in the intermediate layer may be used alone or as a mixture or polycondensate of a plurality of compounds.

[0365] Among them, the intermediate layer is preferably a layer containing an organic metal compound containing zirconium atoms or silicon atoms, for example.

[0366] The formation of the intermediate layer is not particularly limited and can be performed by a known formation method. For example, the intermediate layer can be formed by forming a coating film of an intermediate layer-forming coating liquid prepared by adding the above components to a solvent, drying the coating film, and heating as necessary.

[0367] As a coating method for forming the intermediate layer, a common method such as a dip coating method, a push coating method, a wire bar coating method, a spray coating method, a blade coating method, an air knife coating method, a curtain coating method, etc. can be used.

[0368] The thickness of the intermediate layer is preferably set within a range of, for example, 0.1 μm or more and 3 μm or less. The intermediate layer can be used as an undercoat layer.

[0369] [Charge Generation Layer]

[0370] The charge generating layer is, for example, a layer containing a charge generating material and a binder resin. Furthermore, the charge generating layer may be a vapor-deposited layer of the charge generating material. The vapor-deposited layer of the charge generating material is suitable for the case where an incoherent light source such as an LED (Light Emitting Diode) or an organic EL (Electro-Luminescence) image array is used.

[0371] Examples of the charge generating material include azo pigments such as disazo and trisazo; condensed ring aromatic pigments such as dibromoanthraquinone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; and trigonal selenium.

[0372] Among them, in order to cope with laser exposure in the near-infrared region, metal phthalocyanine pigments or metal-free phthalocyanine pigments are preferably used as charge generating materials, and more specifically, hydroxygallium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine, and oxytitanium phthalocyanine are more preferred.

[0373] On the other hand, in order to cope with laser exposure in the near-ultraviolet region, preferred charge generating materials include condensed ring aromatic pigments such as dibromoanthraquinone, thioindigo pigments, porphyrazine compounds, zinc oxide, trigonal selenium, and disazo pigments.

[0374] The above-mentioned charge generating material can be used even when an incoherent light source such as an LED or an organic EL array having a central wavelength of light emitted in the range of 450 nm to 780 nm is used.

[0375] In contrast, when n-type semiconductors such as condensed aromatic pigments, perylene pigments, and azo pigments are used as charge generating materials, dark current is less likely to be generated, and image defects called black spots can be suppressed even in thin films. The n-type is determined by the polarity of the photocurrent flowing using the commonly used time-of-flight method, and semiconductors that are more likely to flow with electrons as carriers than holes are defined as n-type.

[0376] The binder resin used in the charge generating layer can be selected from a wide range of insulating resins, and can be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinyl anthracene, polyvinyl pyrene, and polysilane.

[0377] Examples of the binder resin include polyvinyl butyral resin, polyarylate resin (condensation products of bisphenols and aromatic dicarboxylic acids), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin, polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, etc. Here, "insulation" means that the volume resistivity is 10 13 These binder resins may be used alone or in combination of two or more.

[0378] The mixing ratio of the charge generating material to the binder resin is preferably in the range of 10:1 to 1:10, for example, in terms of mass ratio.

[0379] Other known additives may be contained in the charge generating layer.

[0380] The formation of the charge generating layer is not particularly limited, and a known formation method can be used, but for example, a coating film of a charge generating layer-forming coating liquid in which the above-mentioned components are added to a solvent is formed, the coating film is dried, and heating is performed as needed. The charge generating layer can be formed by vapor deposition of the charge generating material. The formation of the charge generating layer by vapor deposition is particularly suitable for the case where, for example, a condensed ring aromatic pigment or a perylene pigment is used as the charge generating material.

[0381] Examples of the solvent used for preparing the charge generating layer-forming coating solution include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, dichloromethane, chloroform, chlorobenzene, toluene, etc. These solvents may be used alone or in combination of two or more.

[0382] As a method for dispersing particles (e.g., charge generating materials) in a coating liquid for forming a charge generating layer, for example, a medium disperser such as a ball mill, a vibrating ball mill, a grinder, a sand mill, a horizontal sand mill, or a stirrer, an ultrasonic disperser, a roller mill, a high-pressure homogenizer, or a medium-free disperser can be used. As a high-pressure homogenizer, for example, a collision method in which the dispersion is subjected to liquid-liquid collision or liquid-wall collision under high pressure to disperse it, a penetration method in which a fine flow path is penetrated under high pressure to disperse it, etc. can be cited. When dispersing, the average particle size of the charge generating material in the coating liquid for forming the charge generating layer is set to 0.5 μm or less, for example, preferably to 0.3 μm or less, and more preferably to 0.15 μm or less.

[0383] Examples of a method for applying the charge generating layer forming coating liquid onto the undercoat layer (or the intermediate layer) include common methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0384] The thickness of the charge generating layer is preferably set within the range of, for example, 0.1 μm to 5.0 μm, and more preferably within the range of 0.2 μm to 2.0 μm.

[0385] [Charge transport layer]

[0386] The charge transport layer is, for example, a layer containing a binder resin and a charge transport material. The charge transport layer may be a layer containing a polymer charge transport material.

[0387] As charge transport materials, there can be cited quinone compounds such as p-benzoquinone, chloranil, tetrabromobenzoquinone, anthraquinone, etc.; tetracyanoterephthalene compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; anthrone compounds; benzophenone compounds; cyanoethylene compounds; vinyl compounds and other electron transport compounds. As charge transport materials, there can also be cited triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted vinyl compounds, stilbene compounds, anthracene compounds, hydrazone compounds and other hole transport compounds. These charge transport materials can be used alone or in combination of two or more, but are not limited thereto.

[0388] From the viewpoint of charge mobility, the charge transport material is preferably, for example, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2).

[0389] [Chemical formula 27]

[0390]

[0391] In the structural formula (a-1), Ar T1 ,ArT2 and Ar T3 Each independently represents a substituted or unsubstituted aryl group, -C6H4-C(R T4 )=C(R T5 )(R T6 ) or -C6H4-CH=CH-CH=C(R T7 )(R T8 ). T4 , R T5 , R T6 , R T7 and R T8 Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.

[0392] Examples of substituents of the above groups include halogen atoms, alkyl groups having 1 to 5 carbon atoms, and alkoxy groups having 1 to 5 carbon atoms. In addition, examples of substituents of the above groups include substituted amino groups substituted with alkyl groups having 1 to 3 carbon atoms.

[0393] [Chemical formula 28]

[0394]

[0395] In the structural formula (a-2), R T91 and R T92 R each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. T101 , R T102 , R T111 and R T112 each independently represents a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted by an alkyl group having 1 to 2 carbon atoms, a substituted or unsubstituted aryl group, -C(R T12 )=C(R T13 )(R T14 ) or -CH=CH-CH=C(R T15 )(R T16 ), R T12 , R T13 , R T14 , R T15 and R T16 Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, ​​Tn1, and Tn2 each independently represent an integer of 0 or more and 2 or less.

[0396] Examples of substituents of the above groups include halogen atoms, alkyl groups having 1 to 5 carbon atoms, and alkoxy groups having 1 to 5 carbon atoms. In addition, examples of substituents of the above groups include substituted amino groups substituted with alkyl groups having 1 to 3 carbon atoms.

[0397] From the viewpoint of charge mobility, among the triarylamine derivatives represented by the structural formula (a-1) and the benzidine derivatives represented by the structural formula (a-2), for example, those having "-C6H4-CH=CH-CH=C(R T7 )(R T8 )" and triarylamine derivatives having "-CH=CH-CH=C(R T15 )(R T16 )" benzidine derivatives.

[0398] As the polymer charge transport material, known materials having charge transport properties such as poly-N-vinyl carbazole and polysilane can be cited. In particular, polyester-based polymer charge transport materials are particularly preferred. The polymer charge transport material can be used alone or in combination with a binder resin.

[0399] The binder resin used in the charge transport layer can be polycarbonate resin, polyester resin, polyarylate resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinyl carbazole, polysilane, etc. Among them, as a binder resin, for example, preferably polycarbonate resin or polyarylate resin. These binder resins are used alone or in combination of two or more.

[0400] The mixing ratio of the charge transport material to the binder resin is preferably, for example, 10:1 to 1:5 in terms of mass ratio.

[0401] Other known additives may be contained in the charge transport layer.

[0402] The charge transport layer can be formed without particular limitation and can be formed by a known method. For example, a coating film of a charge transport layer-forming coating liquid is formed by adding the above components to a solvent, and the coating film is dried and heated as necessary.

[0403] As the solvent for preparing the coating solution for forming the charge transport layer, there can be mentioned aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; ketones such as acetone and 2-butanone; halogenated aliphatic hydrocarbons such as dichloromethane, chloroform, and dichloroethane; cyclic or linear ethers such as tetrahydrofuran and diethyl ether, and other common organic solvents. These solvents can be used alone or in combination of two or more.

[0404] Examples of a coating method for coating the charge transport layer-forming coating liquid on the charge generating layer include common methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0405] The thickness of the charge transport layer is preferably set within a range of, for example, 5 μm to 50 μm, and more preferably within a range of 10 μm to 30 μm.

[0406] [Protective layer]

[0407] The protective layer is provided on the photosensitive layer as required. The protective layer is provided, for example, to prevent chemical changes in the photosensitive layer during charging or to further improve the mechanical strength of the photosensitive layer.

[0408] Therefore, for example, a layer composed of a cured film (crosslinked film) is preferably used as the protective layer. Examples of these layers include the layers shown in the following 1) or 2).

[0409] 1) A layer consisting of a cured film of a composition containing a reactive group-containing charge transport material having a reactive group and a charge transport skeleton in the same molecule (i.e., a layer containing a polymer or a crosslinked body of the reactive group-containing charge transport material)

[0410] 2) A layer composed of a cured film of a composition comprising a non-reactive charge transport material and a non-charge transport material having a reactive group but not having a charge transport skeleton (i.e., a layer comprising a non-reactive charge transport material and a polymer or a crosslinked body of the non-charge transport material having a reactive group)

[0411] Examples of the reactive group of the charge transport material containing a reactive group include a chain polymerizable group, an epoxy group, -OH, -OR [wherein R represents an alkyl group], -NH2, -SH, -COOH, -SiR Q1 3-Qn (OR Q2 ) Qn [Among them, R Q1 represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted aryl group, R Q2 represents a hydrogen atom, an alkyl group, a trialkylsilyl group, Qn represents an integer of 1 to 3] and the like.

[0412] As a chain polymerizable group, there is no particular limitation as long as it is a functional group capable of free radical polymerization, and for example, it is a functional group having a group containing at least a carbon double bond. Specifically, there can be mentioned a group containing at least one selected from vinyl, vinyl ether, vinyl sulfide, styryl (vinyl phenyl), acryloyl, methacryloyl and their derivatives. Among them, due to its excellent reactivity, as a chain polymerizable group, for example, it is preferably a group containing at least one selected from vinyl, styryl (vinyl phenyl), acryloyl, methacryloyl and their derivatives.

[0413] The charge transport skeleton of the charge transport material containing a reactive group is not particularly limited as long as it is a known structure in an electrophotographic photoreceptor, and examples thereof include skeletons derived from nitrogen-containing hole transport compounds such as triarylamine compounds, benzidine compounds, and hydrazone compounds, and structures conjugated with nitrogen atoms. Among them, for example, a triarylamine skeleton is preferred.

[0414] The reactive group-containing charge transport material, the non-reactive charge transport material, and the reactive group-containing non-charge transport material having these reactive groups and charge transport skeletons may be selected from known materials.

[0415] Other known additives may be contained in the protective layer.

[0416] The protective layer can be formed by any known method without particular limitation, and can be formed by, for example, forming a coating film of a protective layer-forming coating liquid prepared by adding the above components to a solvent, drying the coating film, and performing a curing treatment such as heating as necessary.

[0417] Examples of the solvent used to prepare the protective layer-forming coating solution include aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as tetrahydrofuran and dioxane; cellosolve solvents such as ethylene glycol monomethyl ether; alcohol solvents such as isopropyl alcohol and butanol, etc. These solvents may be used alone or in combination of two or more.

[0418] The protective layer-forming coating liquid may be a solvent-free coating liquid.

[0419] Examples of a method for applying the protective layer-forming coating liquid onto a photosensitive layer (eg, charge transport layer) include common methods such as dip coating, push coating, wire bar coating, spray coating, blade coating, air knife coating, and curtain coating.

[0420] The film thickness of the protective layer is preferably set within the range of, for example, 1 μm to 20 μm, and more preferably within the range of 2 μm to 10 μm.

[0421] [Single-layer photosensitive layer]

[0422] The single-layer photosensitive layer (charge generation / charge transport layer) is, for example, a layer containing a charge generation material, a charge transport material, and, if necessary, a binder resin and other known additives. These materials are the same as those described for the charge generation layer and the charge transport layer.

[0423] In the single-layer photosensitive layer, the content of the charge generating material relative to the total solid content may be, for example, 0.1% by mass or more and 10% by mass or less, preferably 0.8% by mass or more and 5% by mass or less. In addition, in the single-layer photosensitive layer, the content of the charge transporting material relative to the total solid content may be, for example, 5% by mass or more and 50% by mass or less.

[0424] The method for forming the single-layer photosensitive layer is the same as the method for forming the charge generating layer or the charge transporting layer.

[0425] The film thickness of the single-layer photosensitive layer may be, for example, 5 μm or more and 50 μm or less, and preferably 10 μm or more and 40 μm or less.

[0426] <Image forming apparatus, process cartridge>

[0427] The image forming apparatus according to the present embodiment includes an electrophotographic photoreceptor, a charging device for charging the surface of the electrophotographic photoreceptor, an electrostatic latent image forming device for forming an electrostatic latent image on the surface of the charged electrophotographic photoreceptor, a developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image, a transfer device for transferring the toner image to the surface of a recording medium, and a cleaning device for cleaning the surface of the electrophotographic photoreceptor. In addition, as the electrophotographic photoreceptor, the electrophotographic photoreceptor according to the present embodiment is applicable.

[0428] In the image forming apparatus involved in this embodiment, the charging device is a charging device that has a charging component that is in direct contact with the photosensitive body and applies a voltage in which an AC voltage is superimposed on a DC voltage to the charging component. When this charging device is used, the fine line reproducibility and wear resistance caused by the surface properties of the photosensitive body are easily apparent, and the effect exerted by the photosensitive body of this embodiment (excellent fine line reproducibility and wear resistance) is significantly exerted.

[0429] In the image forming apparatus according to the present embodiment, the cleaning device cleans the surface of the photoreceptor after the toner image is transferred and before the photoreceptor is charged. The cleaning device includes a cleaning member that contacts the outer peripheral surface of the photoreceptor. The photoreceptor according to the present embodiment has excellent wear resistance, so the cleaning member can contact the outer peripheral surface of the photoreceptor.

[0430] The image forming apparatus involved in this embodiment is applicable to the following well-known image forming apparatuses: an apparatus equipped with a fixing device for fixing a toner image transferred to the surface of a recording medium; an apparatus using a direct transfer method for directly transferring a toner image formed on the surface of an electrophotographic photosensitive body to a recording medium; an apparatus using an intermediate transfer method for transferring a toner image formed on the surface of an electrophotographic photosensitive body once to the surface of an intermediate transfer body, and for a second time transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; an apparatus equipped with an anti-static device for eliminating static electricity by irradiating the surface of the electrophotographic photosensitive body with anti-static light after transferring the toner image and before charging; and an apparatus equipped with an electrophotographic photosensitive body heating component for increasing the temperature of the electrophotographic photosensitive body and lowering the relative temperature, etc.

[0431] In the case of an intermediate transfer type device, the transfer device, for example, is applicable to the following structure, which has an intermediate transfer body that transfers the toner image on the surface, a primary transfer device that transfers the toner image formed on the surface of the electronic photographic photosensitive body to the surface of the intermediate transfer body for the first time, and a secondary transfer device that transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium for the second time.

[0432] The image forming apparatus according to the present embodiment may be any of a dry developing system image forming apparatus and a wet developing system (development system using a liquid developer) image forming apparatus.

[0433] In the image forming apparatus according to the present embodiment, for example, the portion having the electrophotographic photoreceptor may be a cartridge structure (processing cartridge) that is detachable from the image forming apparatus. As the processing cartridge, for example, a processing cartridge having the electrophotographic photoreceptor according to the present embodiment is preferably used. In the processing cartridge, in addition to the electrophotographic photoreceptor, for example, at least one selected from the group consisting of a charging device, an electrostatic latent image forming device, a developing device, and a transfer device may be provided.

[0434] An example of the image forming apparatus according to the present embodiment is shown below, but the present invention is not limited thereto. The main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0435] Figure 3 It is a schematic configuration diagram showing an example of the image forming apparatus according to the present embodiment.

[0436] like Figure 3As shown, the image forming apparatus 100 according to the present embodiment includes a process box 300 having an electrophotographic photoreceptor 7, an exposure device 9 (an example of an electrostatic latent image forming device), a transfer device 40 (a primary transfer device), and an intermediate transfer body 50. In the image forming apparatus 100, the exposure device 9 is arranged at a position capable of exposing the electrophotographic photoreceptor 7 from the opening of the process box 300, and the transfer device 40 is arranged at a position opposed to the electrophotographic photoreceptor 7 with the intermediate transfer body 50 interposed therebetween, and the intermediate transfer body 50 is arranged so that a part thereof contacts the electrophotographic photoreceptor 7. Although not shown in the figure, a secondary transfer device is further provided for transferring the toner image transferred to the intermediate transfer body 50 to a recording medium (e.g., paper). The intermediate transfer body 50, the transfer device 40 (a primary transfer device), and the secondary transfer device (not shown in the figure) correspond to an example of a transfer device.

[0437] Figure 3 The process box 300 in the embodiment integrally supports the electrophotographic photoreceptor 7, the charging device 8 (an example of a charging device), the developing device 11 (an example of a developing device), and the cleaning device 13 (an example of a cleaning device) in a housing. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is configured to contact the surface of the electrophotographic photoreceptor 7. The cleaning member may be a conductive or insulating fibrous member instead of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

[0438] exist Figure 3 In the example shown, as the image forming apparatus, a fibrous member 132 (roller-shaped) for supplying lubricant 14 to the surface of electrophotographic photoreceptor 7 and a fibrous member 133 (flat brush-shaped) for assisting cleaning are provided, but these may be arranged as necessary.

[0439] Hereinafter, each structure of the image forming apparatus according to the present embodiment will be described.

[0440] -Electrified Devices-

[0441] As the charging device 8, for example, a contact type charging component using a conductive or semi-conductive charging roller, a charging brush, a charging film, a charging rubber scraper, a charging hose, etc. can be used. The charging device 8 is a charging device in which a voltage having an AC voltage superimposed on a DC voltage is applied to the contact type charging component.

[0442] -Exposure device-

[0443] As the exposure device 9, for example, there can be cited an optical system device that exposes semiconductor laser, LED light, liquid crystal shutter light, etc. on the surface of the electrophotographic photoreceptor 7 to a prescribed pattern. The wavelength of the light source is set within the spectral sensitivity region of the electrophotographic photoreceptor. As the wavelength of the semiconductor laser, near-infrared light with an oscillation wavelength near 780nm is the mainstream. However, it is not limited to this wavelength. As an oscillation wavelength laser or a blue laser in the 600nm band, a laser with an oscillation wavelength in the range of more than 400nm and less than 450nm can also be used. In addition, a surface-emitting laser light source of the type that can output multiple beams in order to form a color image is also effective.

[0444] -Developing device-

[0445] As the developing device 11, for example, a general developing device that develops by contact or non-contact with a developer can be cited. As the developing device 11, there is no particular limitation as long as it has the above-mentioned function, and it can be selected according to the purpose. For example, a known developer having a function of attaching a single-component developer or a two-component developer to the electrophotographic photoreceptor 7 using a brush, a roller, etc. can be cited. Among them, for example, a developer using a developing roller that holds the developer on the surface is preferred.

[0446] The developer used in the developing device 11 may be a single-component developer containing only a toner, or a two-component developer containing a toner and a carrier. Furthermore, the developer may be magnetic or non-magnetic. These developers are suitable for known developers.

[0447] -Cleaning device-

[0448] The cleaning device 13 may be a cleaning blade type device including a cleaning blade 131. In addition to the cleaning blade type, a brush cleaning method or a simultaneous development cleaning method may be used.

[0449] -Transfer device-

[0450] Examples of the transfer device 40 include a contact transfer charger using a belt, a roller, a film, a rubber blade, etc.; a corotron transfer charger using corona discharge; a corotron transfer charger, etc., which are known per se.

[0451] -Intermediate transfer body-

[0452] As the intermediate transfer body 50, a belt-shaped transfer body (intermediate transfer belt) made of polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber, etc. imparted with semiconductivity can be used. In addition, as a form of the intermediate transfer body, a roller-shaped transfer body can be used.

[0453] Figure 4It is a schematic configuration diagram showing another example of the image forming apparatus according to the present embodiment.

[0454] Figure 4 The image forming apparatus 120 shown is a multi-color image forming apparatus of a tandem type equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged on the intermediate transfer body 50, respectively, and a single electrophotographic photoreceptor is used for each color. The image forming apparatus 120 has the same structure as the image forming apparatus 100 except for the tandem type.

[0455] Example

[0456] Hereinafter, embodiments of the present invention will be described in detail based on examples, but embodiments of the present invention are not limited to these examples.

[0457] In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0458] In the following description, unless otherwise specified, synthesis, production, treatment, measurement, etc. were performed at room temperature (25° C.±3° C.).

[0459] <Synthesis of polyester resin (1)>

[0460] A polyester resin (1) or polyester resin (1-1) was synthesized. In the synthesis of the resin, polymerization was carried out in the presence of 4-tert-butylphenol as a terminal blocking agent to block the terminals of the polyester resin.

[0461] Table 1 shows the units and composition constituting the polyester resin (1-1).

[0462] A2-3 described in Table 1 is a specific example of the dicarboxylic acid unit (A) described above.

[0463] B1-4 described in Table 1 is a specific example of the diol unit (B) described above.

[0464] [Table 1]

[0465]

[0466] <Example 1>

[0467] As the conductive substrate, an aluminum cylindrical tube having an outer diameter of 30 mm, a length of 250 mm, and a wall thickness of 1 mm was prepared.

[0468] [Formation of undercoat layer]

[0469] Zinc oxide (average particle size 70 nm, specific surface area 15 m 2 / g, manufactured by TAYCA CORPORATION) and 500 parts of toluene were mixed and stirred, and 1.3 parts of a silane coupling agent (trade name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd., N-2-(aminoethyl)-3-aminopropyltrimethoxysilane) were added, and stirred for 2 hours. Then, toluene was distilled under reduced pressure and sintered at 120° C. for 3 hours to obtain zinc oxide surface-treated with a silane coupling agent.

[0470] 110 parts of surface-treated zinc oxide and 500 parts of tetrahydrofuran were mixed and stirred, and a solution of 0.6 parts of alizarin dissolved in 50 parts of tetrahydrofuran was added, followed by stirring at 50° C. for 5 hours. Then, the solid content was filtered out by vacuum filtration and dried at 60° C. to obtain zinc oxide with alizarin.

[0471] 60 parts of zinc oxide imparting alizarin, 13.5 parts of curing agent (blocked isocyanate, trade name: SUMIDUR3175, manufactured by Sumitomo Bayer Urethane Co., Ltd.) and 15 parts of butyral resin (trade name: S-LEC BM-1, manufactured by SEKISUI CHEMICAL CO., LTD.) were mixed and dissolved in 100 parts of a solution of 68 parts of methyl ethyl ketone and 5 parts of methyl ethyl ketone, and dispersed for 2 hours in a sand mill using glass beads with a diameter of 1 mm to obtain a dispersion. 0.005 parts of dioctyltin dilaurate and 4 parts of silicone resin particles (trade name: Tospearl145, Momentive performance Materials Inc.) were added to the dispersion as a catalyst to obtain a coating solution for forming an undercoat layer. The coating solution for forming an undercoat layer was applied to the outer peripheral surface of the conductive substrate by a dip coating method, and dried and cured at 170°C for 40 minutes to form an undercoat layer with a layer thickness of 20 μm.

[0472] [Formation of Charge Generation Layer]

[0473] A mixture consisting of 15 parts of hydroxygallium phthalocyanine (having diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1° and 28.3° in the X-ray diffraction spectrum using CuKα characteristic X-rays) as a charge generating material, 10 parts of a vinyl chloride-vinyl acetate copolymer resin (trade name: VMCH, manufactured by Nippon Unicar Company Limited) as a binder resin, and 200 parts of n-butyl acetate was dispersed for 4 hours using glass beads having a diameter of 1 mm and a sand mill. 175 parts of n-butyl acetate and 180 parts of methyl ethyl ketone were added to the dispersion, and the mixture was stirred to obtain a coating liquid for forming a charge generating layer. The coating liquid for forming a charge generating layer was dip-coated on the undercoat layer and dried at room temperature to form a charge generating layer having a layer thickness of 0.25 μm.

[0474] [Formation of Charge Transport Layer]

[0475] ·Binder resin: polyester resin (-1-1) ... 60 parts

[0476] Charge transport material: CTM-1...40 parts

[0477] Solvent: Tetrahydrofuran...270 parts

[0478] Solvent: Toluene... 30 parts

[0479] The above materials were stirred and mixed to obtain a charge transport layer-forming coating liquid, which was dip-coated on the charge generating layer and dried at 145° C. for 30 minutes to form a charge transport layer with a thickness of 30 μm.

[0480] [Chemical formula 29]

[0481]

[0482] <Examples 2 to 14, Comparative Example 1>

[0483] In forming the charge transport layer, each photoreceptor was prepared in the same manner as in Example 1, except that part or all of the polyester resin (1-1) was replaced with a polycarbonate resin (PC1) and / or the ratio of the binder resin was changed as described in Table 2.

[0484] [Chemical formula 30]

[0485]

[0486] In the formula, 75 and 25 represent molar ratios (mol %).

[0487] <Comparative Example 2>

[0488] In the formation of the charge transport layer, the polyester resin (1-1) was replaced with a polycarbonate resin (PC1), and PTFE particles (polytetrafluoroethylene particles) having an average particle size of 3.3 μm were used. The photoreceptor of Comparative Example 2 was prepared in the same manner as in Example 1. The mixing ratio of the two components was polycarbonate resin (PC1):PTFE particles = 90:10, and the value recorded in "the proportion of the binder resin in the outermost layer" in Table 2 is the total mass ratio of the polycarbonate resin (PC1) and the PTFE particles.

[0489] <Photoreceptor performance evaluation>

[0490] The photoreceptors of the examples or comparative examples were installed in an electrophotographic image forming apparatus Apeos C7070 (FUJIFILM Business Innovation). The charging device of the image forming apparatus includes a contact type charging roller, and a voltage in which an AC voltage is superimposed on a DC voltage is applied to the contact type charging roller.

[0491] [Thin line reproducibility]

[0492] The "ITE High Definition Test Chart" (DNP INNOVATION PORT) was formed in black on A3-size plain paper under an environment of a temperature of 25° C. and a relative humidity of 55%. The fine line portion was visually confirmed and classified as follows.

[0493] G1: All fine lines are well reproduced.

[0494] G2: Very fine lines are partially blurred and / or thickened. No problem in practical use.

[0495] G3: There are parts where very thin lines are connected to each other. This is acceptable for practical use.

[0496] G4: There are portions where extremely fine lines are connected to each other and portions where fine lines are connected to each other. Not suitable for practical use.

[0497] [Cleanliness]

[0498] 40,000 cyan 30% full-surface halftone images were continuously output on A3-size plain paper at a temperature of 25°C and a relative humidity of 55%. The peripheral surface of the photoreceptor was observed with an optical microscope and classified as follows. The results are shown in Table 2.

[0499] A: No dirt was observed.

[0500] B: There is very slight dirt to the extent that does not cause image defects.

[0501] C: Dirt exists to such an extent that image defects may occur.

[0502] [Wear rate of the outermost layer (charge transport layer)]

[0503] Before and after the above-mentioned image formation for evaluating the cleanliness, the layer thickness of the charge transport layer was measured at 4 locations in the center of the axial direction of the photoreceptor at 90° scale along the circumferential direction. An electromagnetic film thickness meter (FISCHER INSTRUMENTSK.K., PERMASCOPE) was used for the measurement. The 4 layer thicknesses were averaged, and the average value after the image formation was subtracted from the average value before the image formation to calculate the wear amount. The wear rate (nm / kcy) was calculated by dividing the wear amount by the number of photoreceptor travel cycles. The results are shown in Table 2.

[0504]

[0505] The electrophotographic photoreceptor, process cartridge and image forming apparatus of the present invention include the following aspects. Each formula is the same as the above formula with the same number.

[0506] (1) An electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer disposed on the conductive substrate, wherein:

[0507] The outermost layer contains charge transport material and adhesive resin and has a breaking energy of 10mJ / mm 3 The above layers,

[0508] The coefficient of dynamic friction of the outer peripheral surface is 0.5 or more and 1.0 or less.

[0509] (2) The electrophotographic photoreceptor according to (1), wherein

[0510] The dynamic friction coefficient divided by the fracture energy (mJ / mm 3 ) is greater than or equal to 0.05 and less than or equal to 0.10.

[0511] (3) The electrophotographic photoreceptor according to (1) or (2), wherein

[0512] The binder resin includes a polyester resin, and a ratio of the polyester resin in the binder resin is 35 mass % or more and 75 mass % or less.

[0513] (4) The electrophotographic photoreceptor according to any one of (1) to (3), wherein

[0514] The ratio of the binder resin in the outermost surface layer is 50% by mass or more.

[0515] (5) The electrophotographic photoreceptor according to any one of (1) to (4), wherein

[0516] The ratio of the binder resin in the outermost surface layer is 55 mass % or more and 70 mass % or less.

[0517] (6) The electrophotographic photoreceptor according to any one of (1) to (5), wherein

[0518] The binding resin includes two or more resins.

[0519] (7) The electrophotographic photoreceptor according to (6), wherein

[0520] The two or more resins include a polyester resin (1) having a dicarboxylic acid unit (A) represented by the formula (A) and a diol unit (B) represented by the formula (B).

[0521] (8) The electrophotographic photoreceptor according to (7), wherein

[0522] The dicarboxylic acid unit (A) represented by the formula (A) includes at least one selected from the group consisting of a dicarboxylic acid unit (A1) represented by the formula (A1), a dicarboxylic acid unit (A2) represented by the formula (A2), a dicarboxylic acid unit (A3) represented by the formula (A3), and a dicarboxylic acid unit (A4) represented by the formula (A4).

[0523] (9) The electrophotographic photoreceptor according to (7) or (8), wherein

[0524] The diol unit (B) represented by the formula (B) includes at least one selected from the group consisting of a diol unit (B1) represented by the formula (B1), a diol unit (B2) represented by the formula (B2), a diol unit (B3) represented by the formula (B3), a diol unit (B4) represented by the formula (B4), a diol unit (B5) represented by the formula (B5), a diol unit (B6) represented by the formula (B6), a diol unit (B7) represented by the formula (B7) and a diol unit (B8) represented by the formula (B8).

[0525] (10) The electrophotographic photoreceptor according to any one of 6) to (9), wherein

[0526] The two or more resins include a polycarbonate resin.

[0527] (11) The electrophotographic photoreceptor according to any one of (1) to (10), wherein

[0528] The photosensitive layer has a charge generating layer and a charge transporting layer, and the charge transporting layer is the outermost layer.

[0529] (12) A process cartridge comprising:

[0530] The electrophotographic photoreceptor according to any one of (1) to (11); and

[0531] a charging device for charging the surface of the electrophotographic photoreceptor and having a charging member in direct contact with the electrophotographic photoreceptor, wherein a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the charging member;

[0532] The process cartridge is attachable to and detachable from the image forming apparatus.

[0533] (13) An image forming apparatus comprising:

[0534] The electrophotographic photoreceptor according to any one of (1) to (11);

[0535] a charging device for charging the surface of the electrophotographic photoreceptor and having a charging member in direct contact with the electrophotographic photoreceptor, wherein a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the charging member;

[0536] An electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;

[0537] a developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image;

[0538] a transfer device for transferring the toner image to a surface of a recording medium; and

[0539] A cleaning device cleans the surface of the electrophotographic photoreceptor.

[0540] According to (1) or (11), there is provided a method of providing ... 3 Or an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the dynamic friction coefficient of the outer peripheral surface is less than 0.5 or exceeds 1.0.

[0541] According to (2), an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the value of the dynamic friction coefficient divided by the breaking energy is less than 0.05 or exceeds 0.10 is provided.

[0542] According to (3), an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the proportion of the polyester resin in the binder resin is less than 35 mass % or exceeds 75 mass %.

[0543] According to (4), an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the proportion of the binder resin in the outermost surface layer is less than 50 mass % is provided.

[0544] According to (5), an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the proportion of the binder resin in the outermost surface layer is less than 55 mass % or exceeds 70 mass %.

[0545] According to (6), (7), (8), (9) or (10), there is provided an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the binder resin is a single resin.

[0546] According to (12), there is provided a process cartridge having an electrophotographic photoreceptor, wherein the breaking energy of the outermost layer of the electrophotographic photoreceptor is less than 10 mJ / mm 3 Or an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the dynamic friction coefficient of the outer peripheral surface is less than 0.5 or exceeds 1.0.

[0547] According to (13), there is provided an image forming apparatus having an electrophotographic photoreceptor having a fracture energy of less than 10 mJ / mm 3 Or an electrophotographic photoreceptor having excellent thin line reproducibility and abrasion resistance compared with a case where the dynamic friction coefficient of the outer peripheral surface is less than 0.5 or exceeds 1.0.

[0548] The above-mentioned embodiments of the present invention are provided for the purpose of illustration and description. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed methods. Obviously, various modifications and changes are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily understand the principles of the present invention and its application. Thus, other technicians in the art can understand the present invention through various variations optimized for specific uses assumed to be various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. An electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer disposed on the conductive substrate, wherein: The outermost layer contains charge transport material and adhesive resin and has a breaking energy of 10mJ / mm 3 The above layers, The coefficient of dynamic friction of the outer peripheral surface is 0.5 or more and 1.0 or less.

2. The electrophotographic photoreceptor according to claim 1, wherein The dynamic friction coefficient divided by the fracture energy (mJ / mm 3 ) is greater than or equal to 0.05 and less than or equal to 0.

10.

3. The electrophotographic photoreceptor according to claim 1 or 2, wherein The binder resin includes a polyester resin, and a ratio of the polyester resin in the binder resin is 35 mass % or more and 75 mass % or less.

4. The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein The ratio of the binder resin in the outermost surface layer is 50% by mass or more.

5. The electrophotographic photoreceptor according to any one of claims 1 to 4, wherein The ratio of the binder resin in the outermost surface layer is 55 mass % or more and 70 mass % or less.

6. The electrophotographic photoreceptor according to any one of claims 1 to 5, wherein The binding resin includes two or more resins.

7. The electrophotographic photoreceptor according to claim 6, wherein The two or more resins include a polyester resin (1) having a dicarboxylic acid unit (A) represented by the following formula (A) and a diol unit (B) represented by the following formula (B), [Chemical formula 1] Formula (A) Formula ((EB) In formula (A), Ar A1 and Ar A2 are each independently an aromatic ring which may have a substituent, L A is a single bond or a divalent linking group, n A1 is 0, 1, or 2, In formula (B), Ar B1 and Ar B2 are each independently an aromatic ring which may have a substituent, L B is a single bond, oxygen atom, sulfur atom or -C(Rb 1 )(Rb 2 )-,n B1 is 0, 1 or 2, Rb 1 and Rb 2 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and Rb 1 With Rb 2 They may be bonded to form a cyclic alkyl group.

8. The electrophotographic photoreceptor according to claim 7, wherein The dicarboxylic acid unit (A) represented by the formula (A) comprises at least one selected from the group consisting of a dicarboxylic acid unit (A1) represented by the following formula (A1), a dicarboxylic acid unit (A2) represented by the formula (A2), a dicarboxylic acid unit (A3) represented by the formula (A3), and a dicarboxylic acid unit (A4) represented by the formula (A4), [Chemical formula 2] Formula (A1) Formula (A2) Formula (A3) Formula (A4) In formula (A1), n 101 is an integer greater than or equal to 0 and less than or equal to 4, n 101 Ra 101 are each independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, In formula (A2), n 201 and n 202 are each independently an integer of 0 to 4, and n 201 Ra 201 and n 202 Ra 202 are each independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, In formula (A3), n 301 and n 302 are each independently an integer of 0 to 4, and n 301 Ra 301 and n 302 Ra 302 are each independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, In formula (A4), n 401 is an integer greater than or equal to 0 and less than or equal to 6, n 401 Ra 401 Each independently represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

9. The electrophotographic photoreceptor according to claim 7 or 8, wherein The diol unit (B) represented by the formula (B) comprises at least one selected from the group consisting of a diol unit (B1) represented by the following formula (B1), a diol unit (B2) represented by the formula (B2), a diol unit (B3) represented by the formula (B3), a diol unit (B4) represented by the formula (B4), a diol unit (B5) represented by the formula (B5), a diol unit (B6) represented by the formula (B6), a diol unit (B7) represented by the formula (B7) and a diol unit (B8) represented by the formula (B8), [Chemical formula 3] Formula (B1) Formula (B2) Formula (B3) Formula (B4) [Chemical formula 4] Formula (B5) Formula (B6) Formula (B7) Formula (B8) In formula (B1), Rb 101 is a branched alkyl group having 4 to 20 carbon atoms, Rb 201 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 401 , Rb 501 , Rb 801 and Rb 901 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, In formula (B2), Rb 102 is a straight-chain alkyl group having 4 to 20 carbon atoms, Rb 202 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 402 , Rb 502 , Rb 802 and Rb 902 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, In formula (B3), Rb 113 and Rb 213 are each independently a hydrogen atom, a linear alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, d is an integer of 7 to 15, Rb 403 , Rb 503 , Rb 803 and Rb 903 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, In formula (B4), Rb 104 and Rb 204 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 404 , Rb 504 , Rb 804 and Rb 904 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, In formula (B5), Ar 105 is an aryl group having 6 to 12 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, Rb 205 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 405 , Rb 505 , Rb 805 and Rb 905 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, In formula (B6), Rb 116 and Rb 216 are each independently a hydrogen atom, a linear alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, e is an integer of 4 to 6, Rb 406 , Rb 506 , Rb 806 and Rb 906 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, In formula (B7), Rb 407 , Rb 507 , Rb 807 and Rb 907 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom, In formula (B8), Rb 408 , Rb 508 , Rb 808 and Rb 908 Each of them is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

10. The electrophotographic photoreceptor according to any one of claims 6 to 9, wherein The two or more resins include a polycarbonate resin.

11. The electrophotographic photoreceptor according to any one of claims 1 to 10, wherein The photosensitive layer has a charge generating layer and a charge transporting layer, and the charge transporting layer is the outermost layer.

12. A process cartridge comprising: The electrophotographic photoreceptor according to any one of claims 1 to 11; and a charging device for charging the surface of the electrophotographic photoreceptor and having a charging member in direct contact with the electrophotographic photoreceptor, wherein a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the charging member; The process cartridge is attachable to and detachable from the image forming apparatus.

13. An image forming apparatus comprising: The electrophotographic photoreceptor according to any one of claims 1 to 11; a charging device for charging the surface of the electrophotographic photoreceptor and having a charging member in direct contact with the electrophotographic photoreceptor, wherein a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the charging member; An electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; a developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; a transfer device for transferring the toner image to a surface of a recording medium; and A cleaning device cleans the surface of the electrophotographic photoreceptor.

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