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, an undercoat layer disposed on the conductive substrate, and a photosensitive layer disposed on the undercoat layer, the lower coating layer contains a binder resin and at least one purinone compound selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2). The photosensitive layer contains a polyester resin (1) having at least one dicarboxylic acid unit (A) selected from the group consisting of a dicarboxylic acid unit (A2) represented by formula (A2), a dicarboxylic acid unit (A3) represented by formula (A3), and a dicarboxylic acid unit (A4) represented by formula (A4), and a diol unit (B) represented by formula (B). The mass ratio of the polyester resin (1) in the photosensitive layer is 15 mass% or more. [Chemical Formula 1] # imgabs0 # [Chemical Formula 2] # imgabs1 #

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 an electrophotographic photoreceptor including a conductive substrate, an undercoat layer, and a photosensitive layer, wherein the undercoat layer contains a perinone compound and polyurethane.

[0003] Patent Document 2 discloses an electrophotographic photoreceptor including a conductive substrate, an undercoat layer, and a photosensitive layer, wherein the undercoat layer contains a perinone compound and an acceptor compound.

[0004] Patent Document 3 discloses an electrophotographic photoreceptor including a conductive substrate, an undercoat layer, and a photosensitive layer, wherein the undercoat layer contains a perinone compound, an amine compound having an ionization potential of 5.4 eV to 5.9 eV, and a binder resin.

[0005] Patent Document 4 discloses an electrophotographic photoreceptor having an intermediate layer containing N-type semiconductive particles and a photosensitive layer containing a P-type pigment and an N-type pigment on a conductive support.

[0006] Patent document 5 discloses an electrophotographic photosensitive body, which is formed by arranging an intermediate layer and a photosensitive layer on a conductive support body. In the electrophotographic photosensitive body, the intermediate layer contains a polyolefin resin and an organic electron transport substance, and the organic electron transport substance is a compound selected from the group consisting of imide compounds, benzimidazole compounds, quinone compounds, cyclopentadienyl compounds, azo compounds and their derivatives.

[0007] Patent document 6 discloses an electronic photographic photoreceptor having an undercoat layer and a photosensitive layer stacked on a conductive support, wherein at least one of the undercoat layer and the photosensitive layer contains a compound represented by formula A (a compound having a benzimidazole ring introduced on one side of a naphthalenetetracarbonimide skeleton).

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-046640

[0009] Patent Document 2: Japanese Patent Application Publication No. 2020-046641

[0010] Patent Document 3: Japanese Patent Application Publication No. 2020-101652

[0011] Patent Document 4: Japanese Patent Application Publication No. 2004-354697

[0012] Patent Document 5: Japanese Patent Application Publication No. 2011-095665

[0013] Patent Document 6: Japanese Patent Application Publication No. 2021-015223 Summary of the invention

[0014] The object of the present invention is to provide an electronic photographic photosensitive body which has less difference in electrical properties at the beginning and end of repeated image formation than in the case where the mass proportion of polyester resin (1) in the photosensitive layer is less than 15 mass %, is less likely to produce burn-in ghosting in the image, and realizes these over a wider set range involving the intensity of charging and exposure.

[0015] 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.

[0016] <1> An electrophotographic photoreceptor comprising a conductive substrate, an undercoat layer disposed on the conductive substrate, and a photosensitive layer disposed on the undercoat layer, wherein:

[0017] The undercoat layer contains a binder resin and at least one perinone compound selected from the group consisting of a compound represented by formula (1) and a compound represented by formula (2).

[0018] The photosensitive layer contains a polyester resin (1) having at least one dicarboxylic acid unit (A) selected from the group consisting of 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), and a diol unit (B) represented by the formula (B),

[0019] The mass ratio of the polyester resin (1) in the photosensitive layer is 15 mass % or more.

[0020] <2> The electrophotographic photoreceptor according to <1>, wherein

[0021] The mass ratio of the perirone compound in the undercoat layer is 30 mass % or more and 90 mass % or less.

[0022] <3> The electrophotographic photoreceptor according to <1> or <2>, wherein

[0023] The undercoat layer contains polyurethane.

[0024] <4> The electrophotographic photoreceptor according to any one of <1> to <3>, wherein

[0025] The undercoat layer has an average thickness of 5 μm or more and 30 μm or less.

[0026] <5> The electrophotographic photoreceptor according to any one of <1> to <4>, wherein

[0027] The photosensitive layer further contains a polycarbonate resin.

[0028] <6> The electrophotographic photoreceptor according to any one of <1> to <5>, wherein

[0029] The polyester resin (1) comprises at least one diol unit (B) selected from the group consisting of a diol unit (B1) represented by formula (B1), a diol unit (B2) represented by formula (B2), a diol unit (B3) represented by formula (B3), a diol unit (B4) represented by formula (B4), a diol unit (B5) represented by formula (B5), a diol unit (B6) represented by formula (B6), a diol unit (B7) represented by formula (B7) and a diol unit (B8) represented by formula (B8).

[0030] <7> The electrophotographic photoreceptor according to any one of <1> to <6>, wherein

[0031] The photosensitive layer contains gallium phthalocyanine as a charge generating material.

[0032] <8> A process cartridge comprising the electrophotographic photoreceptor according to any one of <1> to <7>,

[0033] The process cartridge is attachable to and detachable from the image forming apparatus.

[0034] <9> An image forming apparatus comprising:

[0035] The electrophotographic photoreceptor according to any one of <1> to <7>;

[0036] A charging device for charging the surface of the electrophotographic photoreceptor;

[0037] An electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;

[0038] 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; and

[0039] The transfer device transfers the toner image to the surface of a recording medium.

[0040] Effects of the Invention

[0041] According to the inventions described in <1>, <3>, <5>, <6> or <7>, there is provided an electronic photographic photosensitive body which has less difference in electrical properties at the beginning and end of repeated image formation and is less likely to produce burn-in ghosting in the image, compared with the case where the mass proportion of the polyester resin (1) in the photosensitive layer is less than 15 mass %, and which achieves these results over a wider set range involving the intensity of charging and exposure.

[0042] According to the invention described in <2>, there is provided an electrophotographic photoreceptor which has less difference in electrical characteristics at the beginning and end of repeated image formation and is less likely to produce burn-in ghosting in the image, compared with the case where the mass ratio of the violacetone compound in the undercoat layer is less than 30 mass % or exceeds 90 mass %, and which achieves these characteristics over a wider set range involving the intensity of charging and exposure.

[0043] According to the invention involved in <4>, there is provided an electronic photographic photosensitive body which has less difference in electrical characteristics at the beginning and end of repeated image formation and is less likely to produce burn-in ghosting in the image, compared with the case where the average thickness of the lower coating layer is less than 5 μm or exceeds 30 μm, and which realizes these characteristics over a wider set range involving the intensity of charging and exposure.

[0044] According to the invention described in <8>, there is provided a processing box having an electronic photographic photosensitive body, that is, an electronic photographic photosensitive body which has less difference in electrical properties at the beginning and end of repeated image formation and is less likely to produce burn-in ghosting in the image, compared with a case where the mass proportion of the polyester resin (1) in the photosensitive layer is less than 15 mass %, and which realizes these characteristics over a wider set range involving the intensity of charging and exposure.

[0045] According to the invention described in <9>, there is provided an image forming apparatus having an electronic photographic photosensitive body, wherein, compared with a case where the mass proportion of the polyester resin (1) in the photosensitive layer is less than 15 mass %, at the initial and final stages of repeated image formation, there is less difference in electrical properties, and it is less likely that burn-in ghosting will occur in the image, and the electronic photographic photosensitive body realizes these characteristics over a wider set range involving the intensity of charging and exposure. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0047] Figure 1 is a partial cross-sectional view showing an example of a layer structure of an electrophotographic photoreceptor according to the present embodiment;

[0048] Figure 2 is a partial cross-sectional view showing another example of the layer structure of the electrophotographic photoreceptor involved in this embodiment;

[0049] Figure 3 is a schematic structural diagram showing an example of an image forming apparatus according to the present embodiment;

[0050] Figure 4 is a schematic structural diagram showing another example of the image forming apparatus involved in this embodiment;

[0051] Figure 5 This is a diagram showing evaluation criteria of ghosting in Examples.

[0052] Explanation of symbols

[0053] 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

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] In the present invention, unless otherwise specified, an alkyl group and an alkylene group include linear, branched, and cyclic groups.

[0062] 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.

[0063] 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.

[0064] In the present invention, the "structural unit" of the copolymer or resin has the same meaning as the monomer unit.

[0065] <Electronic Photographic Photoreceptor>

[0066] The electrophotographic photoreceptor (hereinafter also referred to as “photoreceptor”) according to the present embodiment includes a conductive substrate, an undercoat layer disposed on the conductive substrate, and a photosensitive layer disposed on the undercoat layer.

[0067] Figure 1 This 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.

[0068] 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.

[0069] In the photoreceptor according to this embodiment,

[0070] The undercoat layer contains a binder resin and at least one perinone compound selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2).

[0071] The photosensitive layer contains a polyester resin (1) having at least one dicarboxylic acid unit (A) selected from the group consisting of a dicarboxylic acid unit (A2) represented by the following formula (A2), a dicarboxylic acid unit (A3) represented by the following formula (A3) and a dicarboxylic acid unit (A4) represented by the following formula (A4), and a diol unit (B) represented by the following formula (B).

[0072] The mass ratio of the polyester resin (1) in the photosensitive layer is 15 mass % or more.

[0073] [Chemical formula 1]

[0074] Formula (1)

[0075] Formula (2)

[0076] In formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 R each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom. 11 With R 12 , R 12 With R 13 and R 13 With R 14 They may independently bond to each other to form a ring. 15 With R 16 , R 16 With R 17 and R 17 With R 18 They may be independently bonded to each other to form a ring.

[0077] In formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 R each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom. 21 With R 22 , R 22 With R 23 and R 23 With R24 They may independently bond to each other to form a ring. 25 With R 26 , R 26 With R 27 and R 27 With R 28 They may be independently bonded to each other to form a ring.

[0078] [Chemical formula 2]

[0079] Formula (A2)

[0080] Formula (A3)

[0081] Formula (A4)

[0082] Formula (B)

[0083] 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.

[0084] 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 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.

[0085] 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.

[0086] 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.

[0087] In the present invention, the compound represented by formula (1) is referred to as a perione compound (1), and the compound represented by formula (2) is referred to as a perione compound (2).

[0088] When the photosensitive layer of the photoreceptor according to this embodiment is Figure 1 When the photoreceptor 10A shown is a laminated photosensitive layer composed of a charge generating layer and a charge transporting layer, at least the charge transporting layer contains the polyester resin (1). The charge generating layer may contain the polyester resin (1) or may not contain the polyester resin (1).

[0089] The photoreceptor of the present embodiment has little difference in electrical characteristics at the beginning and end of repeated image formation, and is not prone to producing burn-in ghosting in the image, and achieves these over a wide set range involving charging and exposure intensity. "Burn-in ghosting" refers to an image defect in which the surface potential of the photosensitive layer decreases in an area with a lot of exposure history, and the density of the halftone image becomes thicker.

[0090] The mechanism by which the photoreceptor according to the present embodiment exerts the above-mentioned effect is presumed to be as follows.

[0091] It is known that when the perolone compound (1) and / or the perolone compound (2) is used in the undercoat layer, good initial electrical characteristics can be obtained.

[0092] Here, it is considered that when a resin other than the polyester resin (1) is used in the photosensitive layer (charge transport layer in the case of a laminated photosensitive layer), the difference between the electron injection property from the photosensitive layer (charge generation layer in the case of a laminated photosensitive layer) to the lower coating layer during exposure and the hole injection property from the charge generation material in the photosensitive layer to the charge transport material (from the charge generation layer to the charge transport layer in the case of a laminated photosensitive layer) is large, and the charge is gradually accumulated due to the repetition of exposure and charging. As a result, the difference in electrical characteristics becomes large at the beginning and end of repeated image formation.

[0093] It is considered that the accumulation of the electric charge is remarkable in a portion with a large exposure history, and as a result, a burn-in ghost is generated in the image.

[0094] Furthermore, it is believed that if the charging and exposure conditions are changed, the difference between the above-mentioned "electron injection property" and "hole injection property" will also change greatly. As a result, the difference in electrical characteristics and the generation of ghosting will also change at the beginning and end of repeated image formation.

[0095] On the other hand, it is considered that when the polyester resin (1) is used in the photosensitive layer (charge transport layer in the case of a laminated photosensitive layer), the difference between the above-mentioned "electron injection property" and "hole injection property" becomes smaller.

[0096] As a result, there is little difference in electrical characteristics at the beginning and end of repeated image formation, and it is difficult to produce a burn-in ghost in the image. Moreover, this is achieved over a wide setting range involving charging and exposure conditions.

[0097] In the photoreceptor according to the present embodiment, the mass ratio of the polyester resin (1) in the photosensitive layer is 15 mass % or more. If the mass ratio of the polyester resin (1) in the photosensitive layer is less than 15 mass %, the film strength and crack resistance of the photosensitive layer become insufficient, thereby reducing the maintenance of electrical properties. From the viewpoint of suppressing this phenomenon, the mass ratio of the polyester resin (1) in the photosensitive layer is 15 mass % or more, for example, preferably 20 mass % or more, and more preferably 25 mass % or more.

[0098] From the viewpoint of initial electrical characteristics, the mass ratio of the polyester resin (1) in the photosensitive layer is, for example, preferably 80 mass % or less, more preferably 75 mass % or less, and further preferably 70 mass % or less.

[0099] In the photoreceptor involved in this embodiment, from the viewpoint of imparting electrical properties suitable for electronic photography to the undercoat layer, the mass proportion of the violacetone compound in the undercoat layer (the total mass proportion of the violacetone compound (1) and the violacetone compound (2)) is preferably 30 mass % or more, more preferably 40 mass % or more, and further preferably 50 mass % or more.

[0100] From the viewpoint of the softness and elasticity of the undercoat layer, the mass ratio of the perirone compound in the undercoat layer (the mass ratio of the perirone compound (1) and the perirone compound (2) in total) is, for example, preferably 90 mass % or less, more preferably 80 mass % or less, and further preferably 70 mass % or less.

[0101] Hereinafter, the perirone compound, the polyester resin (1), and each layer of the photoreceptor will be described in detail in order.

[0102] [Periodone compound (1), periodone compound (2)]

[0103] The perone compound (1) is a compound represented by the following formula (1). The perone compound (2) is a compound represented by the following formula (2).

[0104] [Chemical formula 3]

[0105] Formula (1)

[0106] Formula (2)

[0107] In formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 R each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom. 11 With R 12 , R 12 With R 13 and R 13 With R 14 They may independently bond to each other to form a ring. 15 With R 16 , R 16 With R 17 and R 17 With R 18 They may be independently bonded to each other to form a ring.

[0108] In formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 R each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom. 21 With R 22 , R 22 With R 23 and R 23 With R 24 They may independently bond to each other to form a ring. 25 With R 26 , R 26 With R 27 and R 27 With R 28They may be independently bonded to each other to form a ring.

[0109] As R in formula (1) 11 ~R 18 The alkyl group represented by may be a substituted or unsubstituted alkyl group.

[0110] As R in formula (1) 11 ~R 18 The unsubstituted alkyl group represented by the present invention includes a straight-chain alkyl group having 1 to 20 carbon atoms (for example, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms), a branched alkyl group having 3 to 20 carbon atoms (for example, preferably 3 to 10 carbon atoms), and a cyclic alkyl group having 3 to 20 carbon atoms (for example, preferably 3 to 10 carbon atoms).

[0111] Examples of the straight-chain alkyl group having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, 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.

[0112] Examples of the branched alkyl group having 3 to 20 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, tert-decyl, isododecyl, sec-dodecyl, tert-dodecyl, tert-tetradecyl, and tert-pentadecyl.

[0113] Examples of the cyclic alkyl group having 3 to 20 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.

[0114] Among the above, the unsubstituted alkyl group is preferably a linear alkyl group such as a methyl group or an ethyl group.

[0115] Examples of the substituent in the alkyl group include an alkoxy group, a hydroxyl group, a carboxyl group, a nitro group, and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0116] Examples of the alkoxy group substituting the hydrogen atom in the alkyl group include: 11 ~R 18 The same groups as the unsubstituted alkoxy groups represented.

[0117] As R in formula (1)11 ~R 18 The alkoxy group represented by may be a substituted or unsubstituted alkoxy group.

[0118] As R in formula (1) 11 ~R 18 Examples of the unsubstituted alkoxy group represented by the above include linear, branched or cyclic alkoxy groups having 1 to 10 carbon atoms (for example, preferably 1 to 6, more preferably 1 to 4).

[0119] Specific examples of the linear alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, and an n-decyloxy group.

[0120] Specifically, examples of the branched alkoxy group include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy, tert-hexyloxy, isoheptyloxy, sec-heptyloxy, tert-heptyloxy, isooctyloxy, sec-octyloxy, tert-octyloxy, isononyloxy, sec-nonyloxy, tert-nonyloxy, isodecyloxy, sec-decyloxy, and tert-decyloxy.

[0121] Specific examples of the cyclic alkoxy group include a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, a cyclooctyloxy group, a cyclononyloxy group, and a cyclodecyloxy group.

[0122] Among them, as the unsubstituted alkoxy group, for example, a linear alkoxy group is preferred.

[0123] Examples of the substituent in the alkoxy group include an aryl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a hydroxyl group, a carboxyl group, a nitro group, and a halogen atom (such as a fluorine atom, a bromine atom, and an iodine atom).

[0124] Examples of the aryl group that replaces the hydrogen atom in the alkoxy group include the following: 11 ~R 18 The same groups as those represented by the unsubstituted aryl groups.

[0125] Examples of the alkoxycarbonyl group that replaces the hydrogen atom in the alkoxy group include the following: 11 ~R 18 The same groups as the unsubstituted alkoxycarbonyl groups represented.

[0126] Examples of the aryloxycarbonyl group which may replace the hydrogen atom in the alkoxy group include the following: 11 ~R 18 The same groups as the unsubstituted aryloxycarbonyl groups represented.

[0127] As R in formula (1) 11 ~R18 The aralkyl group represented by may be a substituted or unsubstituted aralkyl group.

[0128] As R in formula (1) 11 ~R 18 The unsubstituted aralkyl group represented is, for example, preferably an aralkyl group having 7 to 30 carbon atoms, more preferably an aralkyl group having 7 to 16 carbon atoms, and still more preferably an aralkyl group having 7 to 12 carbon atoms.

[0129] Examples of the unsubstituted aralkyl group having 7 to 30 carbon atoms include benzyl, phenylethyl, phenylpropyl, 4-phenylbutyl, phenylpentyl, phenylhexyl, phenylheptyl, phenyloctyl, phenylnonyl, naphthylmethyl, naphthylethyl, anthracenylmethyl, and phenyl-cyclopentylmethyl.

[0130] Examples of the substituent in the aralkyl group include an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0131] Examples of the alkoxy group substituting the hydrogen atom in the aralkyl group include: 11 ~R 18 The same groups as the unsubstituted alkoxy groups represented.

[0132] Examples of the alkoxycarbonyl group which may replace the hydrogen atom in the aralkyl group include the following: 11 ~R 18 The same groups as the unsubstituted alkoxycarbonyl groups represented.

[0133] Examples of the aryloxycarbonyl group which replaces the hydrogen atom in the aralkyl group include the following: 11 ~R 18 The same groups as the unsubstituted aryloxycarbonyl groups represented.

[0134] As R in formula (1) 11 ~R 18 The aryl group represented by may be a substituted or unsubstituted aryl group.

[0135] As R in formula (1) 11 ~R 18 The unsubstituted aryl group represented by is, for example, preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 14 carbon atoms, and further preferably an aryl group having 6 to 10 carbon atoms.

[0136] Examples of the aryl group having 6 to 30 carbon atoms include phenyl, biphenyl, 1-naphthyl, 2-naphthyl, 9-anthryl, 9-phenanthryl, 1-pyrenyl, 5-naphthyl, 1-indenyl, 2-azulyl, 9-fluorenyl, biphenylene, indacenyl, fluoranthenyl, acenaphthyl, acenaphthylene, phenanthrenyl, fluorenyl, anthracenyl, anthracenyl, anthracenyl, anthracenyl, anthracenyl, anthracenyl, anthracenyl, triphenylene, pyrenyl, chrysenyl, naphthacene, pleiadenyl, picenyl, perylenyl, pentaphenyl, pentacene, tetraphenylene, hexaphenyl, hexacenyl, ruthenyl, and coronenyl. Among the above, for example, phenyl is preferred.

[0137] Examples of the substituent in the aryl group include an alkyl group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0138] Examples of the alkyl group that replaces the hydrogen atom in the aryl group include the following: 11 ~R 18 The same groups as those represented by the unsubstituted alkyl groups.

[0139] Examples of the alkoxy group substituting the hydrogen atom in the aryl group include the following: 11 ~R 18 The same groups as the unsubstituted alkoxy groups represented.

[0140] Examples of the alkoxycarbonyl group that replaces the hydrogen atom in the aryl group include the following: 11 ~R 18 The same groups as the unsubstituted alkoxycarbonyl groups represented.

[0141] Examples of the aryloxycarbonyl group that replaces the hydrogen atom in the aryl group include: 11 ~R 18 The same groups as the unsubstituted aryloxycarbonyl groups represented.

[0142] As R in formula (1) 11 ~R 18 The aryloxy group represented by (—O—Ar, Ar represents an aryl group) may be a substituted or unsubstituted aryloxy group.

[0143] As R in formula (1) 11 ~R 18 The unsubstituted aryloxy group represented by is, for example, preferably an aryloxy group having 6 to 30 carbon atoms, more preferably an aryloxy group having 6 to 14 carbon atoms, and further preferably an aryloxy group having 6 to 10 carbon atoms.

[0144] Examples of the aryloxy group having 6 to 30 carbon atoms include phenoxy, biphenyloxy, 1-naphthyloxy, 2-naphthyloxy, 9-anthryloxy, 9-phenanthrenyloxy, 1-pyreneoxy, 5-tetraphenoxy, 1-indenyloxy, 2-azulyloxy, 9-fluorenyloxy, biphenyleneoxy, indacenyloxy, fluorantheneoxy, acenaphthyleneoxy, acenaphthyleneoxy, phenanthrenyloxy, fluorenyloxy, anthracenyloxy, anthracenyloxy, anthracenyloxy, anthracenyloxy, anthracenyloxy, anthracenyloxy, anthracenyloxy, anthracenyloxy, triphenyleneoxy, pyreneoxy, chryseneoxy, tetraphenoxy, tetrazolyloxy, phenanthrenyloxy, peryleneoxy, pentaphenoxy, pentaphenyloxy, tetraphenyleneoxy, hexaphenoxy, fused hexaphenoxy, ruthenyloxy, and coronaenyloxy. Among the above, for example, phenoxy is preferred.

[0145] Examples of the substituent in the aryloxy group include an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0146] Examples of the alkyl group which may replace the hydrogen atom in the aryloxy group include the following: 11 ~R 18 The same groups as the unsubstituted alkyl groups represented.

[0147] Examples of the alkoxycarbonyl group that replaces the hydrogen atom in the aryloxy group include the following: 11 ~R 18 The same groups as the unsubstituted alkoxycarbonyl groups represented.

[0148] Examples of the aryloxycarbonyl group that replaces the hydrogen atom in the aryloxy group include the following: 11 ~R 18 The same groups as the unsubstituted aryloxycarbonyl groups represented.

[0149] As R in formula (1) 11 ~R 18 The alkoxycarbonyl group (—CO—OR, R represents an alkyl group) represented by the group may be a substituted or unsubstituted alkoxycarbonyl group.

[0150] As R in formula (1) 11 ~R 18 The number of carbon atoms in the alkyl chain of the unsubstituted alkoxycarbonyl group represented is, for example, preferably 1 or more and 20 or less, more preferably 1 or more and 15 or less, and further preferably 1 or more and 10 or less.

[0151] Examples of the alkoxycarbonyl group having an alkyl chain with a carbon number of 1 to 20 include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, sec-butoxybutylcarbonyl, tert-butoxycarbonyl, pentyloxycarbonyl, hexyloxycarbonyl, heptyloxycarbonyl, octyloxycarbonyl, nonyloxy, decyloxycarbonyl, dodecyloxycarbonyl, tridecanyloxycarbonyl, tetradecanyloxycarbonyl, pentadecyloxycarbonyl, hexadecyloxycarbonyl, heptadecanyloxycarbonyl, hexadecyloxycarbonyl, heptadecanyloxycarbonyl, octadecyloxycarbonyl, and eicosyloxycarbonyl.

[0152] Examples of the substituent in the alkoxycarbonyl group include an aryl group, a hydroxyl group and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0153] Examples of the aryl group that replaces the hydrogen atom in the alkoxycarbonyl group include the following: 11 ~R 18 The same groups as those represented by the unsubstituted aryl groups.

[0154] As R in formula (1) 11 ~R 18 The aryloxycarbonyl group (—CO—OAr, Ar represents an aryl group) represented by can be a substituted or unsubstituted aryloxycarbonyl group.

[0155] As R in formula (1) 11 ~R 18 The number of carbon atoms of the aryl group in the unsubstituted aryloxycarbonyl group represented is, for example, preferably 6 or more and 30 or less, more preferably 6 or more and 14 or less, and further preferably 6 or more and 10 or less.

[0156] Examples of the aryloxycarbonyl group having an aryl group having 6 to 30 carbon atoms include a phenoxycarbonyl group, a biphenyloxycarbonyl group, a 1-naphthyloxycarbonyl group, a 2-naphthyloxycarbonyl group, a 9-anthracenyloxycarbonyl group, a 9-phenanthrenyloxycarbonyl group, a 1-pyreneoxycarbonyl group, a 5-naphthyloxycarbonyl group, a 1-indenyloxycarbonyl group, a 2-azulyloxycarbonyl group, a 9-fluorenyloxycarbonyl group, a biphenyleneoxycarbonyl group, an indaceneoxycarbonyl group, a fluorantheneoxycarbonyl group, an acenaphthyleneoxycarbonyl group, an acenaphthyleneoxycarbonyl group, a phenanthrenyl ... Oxycarbonyl, fluorenyloxycarbonyl, anthraceneoxycarbonyl, dianthraceneoxycarbonyl, anthraceneoxycarbonyl, quaternary anthraceneoxycarbonyl, anthraquinoneoxycarbonyl, phenanthryloxycarbonyl, triphenyleneoxycarbonyl, pyreneoxycarbonyl, chryseneoxycarbonyl, tetraphenyleneoxycarbonyl, tetraphenyloxycarbonyl, leptenyloxycarbonyl, peryleneoxycarbonyl, pentaphenyloxycarbonyl, pentaphenyloxycarbonyl, tetraphenyleneoxycarbonyl, hexaphenyloxycarbonyl, fused hexaphenyloxycarbonyl, ruthenyloxycarbonyl, coronarenyloxycarbonyl, etc. Among the above, for example, phenoxycarbonyl is preferred.

[0157] Examples of the substituent in the aryloxycarbonyl group include an alkyl group, a hydroxy group and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0158] Examples of the alkyl group which may substitute for the hydrogen atom of the aryloxycarbonyl group include the following: 11 ~R 18 The same groups as those represented by the unsubstituted alkyl groups.

[0159] As R in formula (1) 11 ~R 18 The alkoxycarbonylalkyl group represented by n H 2n )-CO-OR, R represents an alkyl group, and n represents an integer greater than 1. ) includes substituted or unsubstituted alkoxycarbonylalkyl groups.

[0160] As R in formula (1) 11 ~R 18 The alkoxycarbonyl group (-CO-OR) in the unsubstituted alkoxycarbonylalkyl group represented by the formula (1) may be any of the following: 11 ~R 18 The same groups as the alkoxycarbonyl groups represented.

[0161] As R in formula (1) 11 ~R 18 The alkylene chain (-C n H 2n -), and examples thereof include a linear alkylene chain having 1 to 20 carbon atoms (e.g., preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms), a branched alkylene chain having 3 to 20 carbon atoms (e.g., preferably 3 to 10 carbon atoms), and a cyclic alkylene chain having 3 to 20 carbon atoms (e.g., preferably 3 to 10 carbon atoms).

[0162] Examples of the linear alkylene chain having 1 to 20 carbon atoms include methylene, ethylene, n-propylene, n-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, n-tridecylene, n-tetradecylene, n-pentadecylene, n-heptadecylene, n-octadecylene, n-nonadecylene and the like.

[0163] Examples of the branched alkylene chain having 3 to 20 carbon atoms include isopropylene, isobutylene, sec-butylene, tert-butylene, isopentylene, neopentylene, tert-pentylene, isohexylene, sec-hexylene, tert-hexylene, isoheptylene, sec-heptylene, tert-heptylene, isooctylene, sec-octylene, tert-octylene, isononylene, sec-nonylene, tert-nonylene, isodecylene, sec-decylene, tert-decylene, isododecylene, sec-dodecylene, tert-dodecylene, tert-tetradecylene, and tert-pentadecylene.

[0164] Examples of the cyclic alkylene chain having 3 to 20 carbon atoms include cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, cyclooctylene, cyclononylene, and cyclodecylene.

[0165] Examples of the substituent in the alkoxycarbonylalkyl group include an aryl group, a hydroxyl group and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0166] Examples of the aryl group which may substitute the hydrogen atom of the alkoxycarbonylalkyl group include the following: 11 ~R 18 The same groups as those represented by the unsubstituted aryl groups.

[0167] As R in formula (1) 11 ~R 18 The aryloxycarbonylalkyl group (-(C n H 2n )-CO-OAr, Ar represents an aryl group, and n represents an integer greater than or equal to 1. ) includes substituted or unsubstituted aryloxycarbonylalkyl groups.

[0168] As R in formula (1) 11 ~R 18 The aryloxycarbonyl group (-CO-OAr, Ar represents an aryl group) in the unsubstituted aryloxycarbonylalkyl represented by the formula (1) may be any of the following: 11 ~R 18 The same groups as the aryloxycarbonyl groups represented.

[0169] As R in formula (1) 11 ~R 18 The alkylene chain (-C n H 2n -), which may be the same as R in formula (1) 11 ~R 18 The alkylene chains in the alkoxycarbonylalkyl groups represented are the same.

[0170] Examples of the substituent in the aryloxycarbonylalkyl group include an alkyl group, a hydroxy group and a halogen atom (a fluorine atom, a bromine atom, an iodine atom, etc.).

[0171] Examples of the alkyl group which may substitute for the hydrogen atom of the aryloxycarbonylalkyl group include the following: 11 ~R 18 The same groups as the unsubstituted alkyl groups represented.

[0172] As R in formula (1) 11 ~R 18 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0173] As R in formula (1) 11 With R 12 , R 12 With R 13 , R 13 With R 14 , R 15 With R 16 , R 16 With R 17 or R 17 With R 18 The ring structure formed by bonding to each other includes a benzene ring, a condensed ring having 10 to 18 carbon atoms (naphthalene ring, anthracene ring, phenanthrene ring, Ring (benzo[α]phenanthrene ring), tetracene ring, benzanthracene ring (benzo[α]anthracene ring), triphenylene ring, etc. Among the above, the ring structure to be formed is preferably a benzene ring, for example.

[0174] As R in formula (2) 21 ~R 28 The alkyl group represented by can be exemplified by the same alkyl group as R in formula (1): 11 ~R 18 The alkyl groups represented are the same as those represented.

[0175] As R in formula (2) 21 ~R 28 The alkoxy group represented by can be exemplified by the following: 11 ~R 18 The same groups as the alkoxy groups represented.

[0176] As R in formula (2) 21 ~R 28 The aralkyl group represented by can be exemplified by the same group as R in formula (1): 11 ~R 18 The same groups as the aralkyl groups represented.

[0177] As R in formula (2) 21 ~R 28 The aryl group represented by may be the same as R in formula (1) 11 ~R 18 The same group as the aryl group represented.

[0178] As R in formula (2) 21 ~R 28 The aryloxy group represented by can be exemplified by the same group as R in formula (1) 11 ~R 18 The same groups as those represented by the aryloxy groups.

[0179] As R in formula (2) 21 ~R 28The alkoxycarbonyl group represented by can be exemplified by the group consisting of 11 ~R 18 The same groups as the alkoxycarbonyl groups represented.

[0180] As R in formula (2) 21 ~R 28 The aryloxycarbonyl group represented by can be exemplified by the group consisting of 11 ~R 18 The same groups as the aryloxycarbonyl groups represented.

[0181] As R in formula (2) 21 ~R 28 The alkoxycarbonylalkyl represented by the formula (1) may be 11 ~R 18 The alkoxycarbonylalkyl groups represented are the same groups.

[0182] As R in formula (2) 21 ~R 28 The aryloxycarbonylalkyl represented by the formula (1) may be 11 ~R 18 The same groups as those represented by the aryloxycarbonylalkyl groups.

[0183] As R in formula (2) 21 ~R 28 The halogen atom represented by may be any of the following: 11 ~R 18 The halogen atoms represented are the same atoms.

[0184] As R in formula (2) 21 With R 22 , R 22 With R 23 , R 23 With R 24 , R 25 With R 26 , R 26 With R 27 or R 27 With R 28 The ring structure formed by mutually bonding includes a benzene ring, a condensed ring having 10 to 18 carbon atoms (naphthalene ring, anthracene ring, phenanthrene ring, Ring (benzo[α]phenanthrene ring), tetracene ring, benzanthracene ring (benzo[α]anthracene ring), triphenylene ring, etc. Among the above, the ring structure to be formed is preferably a benzene ring, for example.

[0185] In formula (1), R 11 , R 12 , R 13 , R 14 , R 15, R 16 , R 17 and R 18 For example, each independently preferably is a hydrogen atom, an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group or an aryloxycarbonylalkyl group.

[0186] In formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 For example, each independently of the other is more preferably a hydrogen atom or an alkyl group. Here, the form of the alkyl group is as described above.

[0187] In formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 For example, a hydrogen atom is particularly preferred.

[0188] In formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 For example, each independently preferably is a hydrogen atom, an alkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group or an aryloxycarbonylalkyl group.

[0189] In formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 For example, each independently of the other is more preferably a hydrogen atom or an alkyl group. Here, the form of the alkyl group is as described above.

[0190] In formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 For example, a hydrogen atom is particularly preferred.

[0191] Specific examples of the perirone compound (1) and the perirone compound (2) are shown below, but the present embodiment is not limited thereto. In the following structural formula, Ph represents a phenyl group.

[0192] [Chemical formula 4]

[0193] 1-1

[0194] 1-2

[0195]

[0196] 1-3

[0197]

[0198] 1-4

[0199]

[0200] 1-5

[0201]

[0202] 1-6

[0203]

[0204] 1-7

[0205]

[0206] [Chemical formula 5]

[0207]

[0208] 1-9

[0209]

[0210] 1-10

[0211] 1-11

[0212]

[0213] 1-12

[0214]

[0215] 1-13

[0216]

[0217] [Chemical formula 6]

[0218] 1-14

[0219] 1-15

[0220] 1-16

[0221] 1-17

[0222]

[0223] 1-18

[0224]

[0225] [Chemical formula 7]

[0226] 2-1

[0227] 2-2

[0228] 2-3

[0229]

[0230] 2-4

[0231]

[0232] 2-5

[0233]

[0234] 2-6

[0235]

[0236] 2-7

[0237]

[0238] [Chemical formula 8]

[0239]

[0240] 2-9 2-10

[0241] 2-12

[0242]

[0243] 2-13

[0244] [Chemical formula 9]

[0245] 2-14

[0246] 2-15

[0247] 2-16

[0248] 2-17

[0249] 2-18

[0250]

[0251] Violet ketone compounds (2-1) to (2-18) are in an isomeric relationship with violet ketone compounds (1-1) to (1-18) (the relationship between cis isomers and trans isomers). Violet ketone compounds have a tendency to obtain a mixture of isomers in terms of synthesis. According to a known purification method, a mixture of isomers can be purified from one of the mixture.

[0252] In one embodiment, the undercoat layer contains both a violacetone compound (1) and a violacetone compound (2). When the violacetone compound (1) and the violacetone compound (2) are or are not in an isomeric relationship, the mass ratio of the violacetone compound (1) to the violacetone compound (2) is, for example, preferably violacetone compound (1): violacetone compound (2) = 3:97 to 97:3, more preferably 5:95 to 95:5, and even more preferably 10:90 to 90:10.

[0253] [Polyester resin (1)]

[0254] The photosensitive layer (charge transport layer in the case of a laminated photosensitive layer) contains at least a polyester resin (1) as a binder resin. The polyester resin (1) is a polyester resin having at least one dicarboxylic acid unit (A) selected from the group consisting of 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), and a diol unit (B) represented by the formula (B).

[0255] The polyester resin (1) may contain other dicarboxylic acid units in addition to the dicarboxylic acid units (A). The polyester resin (1) may contain other diol units in addition to the diol units (B).

[0256] The dicarboxylic acid unit (A) is at least one selected from the group consisting of a dicarboxylic acid unit (A2) represented by the following formula (A2), a dicarboxylic acid unit (A3) represented by the formula (A3), and a dicarboxylic acid unit (A4) represented by the formula (A4).

[0257] [Chemical formula 10]

[0258] Formula (A2)

[0259] 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.

[0260] n 201 For example, it is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0261] n 202 For example, it is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0262] [Chemical formula 11]

[0263] Formula (A3)

[0264] 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 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.

[0265] n 301 For example, it is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0266] n 302 For example, it is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0267] [Chemical formula 12]

[0268] Formula (A4)

[0269] In formula (A4), n 401 is an integer greater than or equal to 0 and less than or equal to 6, n 401 Ra 401Each 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.

[0270] 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.

[0271] 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 201 , Ra 202 , Ra 301 , Ra 302 and Ra 401 They are collectively referred to as “Ra” for explanation.

[0272] 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.

[0273] 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.

[0274] 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.

[0275] 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.

[0276] 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.

[0277] Examples of the aryl group having 6 to 12 carbon atoms include phenyl, biphenyl, 1-naphthyl, and 2-naphthyl.

[0278] 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.

[0279] 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.

[0280] 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.

[0281] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, and cyclohexyloxy.

[0282] 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.

[0283] [Chemical formula 13]

[0284]

[0285] 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.

[0286] [Chemical formula 14]

[0287]

[0288] 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.

[0289] [Chemical formula 15]

[0290]

[0291] The dicarboxylic acid unit (A) preferably contains at least one selected from the group consisting of (A2-3), (A3-2) and (A4-3) as the above specific examples, more preferably contains at least one selected from the group consisting of (A2-3) and (A3-2), and further preferably contains at least (A2-3).

[0292] The mass ratio of the total of the dicarboxylic acid units (A2) to (A4) in the polyester resin (1) is, for example, preferably 15 mass % or more and 60 mass % or less.

[0293] When the total mass ratio of the dicarboxylic acid units (A2) to (A4) is 15% by mass or more, the abrasion resistance of the photosensitive layer is good. From this viewpoint, the total mass ratio of the dicarboxylic acid units (A2) to (A4) is, for example, more preferably 20% by mass or more, and further preferably 25% by mass or more.

[0294] When the total mass ratio of the dicarboxylic acid units (A2) to (A4) is 60 mass % or less, peeling of the photosensitive layer can be suppressed. From this viewpoint, the total mass ratio of the dicarboxylic acid units (A2) to (A4) is, for example, more preferably 55 mass % or less, and further preferably 50 mass % or less.

[0295] Examples of other dicarboxylic acid units (A) other than the dicarboxylic acid units (A2) 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.

[0296] The dicarboxylic acid units (A) contained in the polyester resin (1) may be one type or two or more types. That is, the dicarboxylic acid units (A2) to (A4) contained in the polyester resin (1) may be one type or two or more types.

[0297] The diol unit (B) is a structural unit represented by the following formula (B).

[0298] [Chemical formula 16]

[0299] Formula (B)

[0300] 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 Rb1 With Rb 2 They may be bonded to form a cyclic alkyl group.

[0301] 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.

[0302] 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.

[0303] 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.

[0304] 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.

[0305] 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.

[0306] 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.

[0307] 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.

[0308] R1 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.

[0309] 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).

[0310] The diol unit (B) more preferably includes at least one selected from the group consisting of a diol unit (B1), a diol unit (B2), a diol unit (B4), a diol unit (B5) and a diol unit (B6),

[0311] It is more preferred that the polyol contains at least one selected from the group consisting of a diol unit (B1), a diol unit (B2), a diol unit (B5) and a diol unit (B6),

[0312] More preferably, it contains at least one selected from the group consisting of diol units (B1), diol units (B2) and diol units (B6),

[0313] Most preferably, at least one selected from the group consisting of diol units (B1) and diol units (B2) is contained.

[0314] [Chemical formula 17]

[0315] Formula (B1)

[0316] 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.

[0317] R 101The 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.

[0318] [Chemical formula 18]

[0319] Formula (B2)

[0320] 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.

[0321] 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.

[0322] [Chemical formula 19]

[0323] Formula (B3)

[0324] 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 903Each 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.

[0325] 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.

[0326] R 113 and Rb 213 The 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 further preferably 1. Specific examples of the group include methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclopropyloxy, and cyclobutyloxy.

[0327] 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.

[0328] [Chemical formula 20]

[0329] Formula (B4)

[0330] 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.

[0331] 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.

[0332] [Chemical formula 21]

[0333] Formula (B5)

[0334] In formula (B5), Ar105 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.

[0335] Ar 105 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.

[0336] 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.

[0337] [Chemical formula 22]

[0338] Formula (B6)

[0339] 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.

[0340] R 116 and Rb 216The 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.

[0341] R 116 and Rb 216 The 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 further preferably 1. Specific examples of the group include methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclopropyloxy, and cyclobutyloxy.

[0342] 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.

[0343] [Chemical formula 23]

[0344] Formula (B7)

[0345] 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.

[0346] [Chemical formula 24]

[0347] Formula (B8)

[0348] 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.

[0349] 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 205Collectively referred to as "Rb 200 " to explain.

[0350] R 200 The 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.

[0351] 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.

[0352] 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.

[0353] 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.

[0354] 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.

[0355] Examples of the branched alkyl group having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl and tert-butyl.

[0356] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0357] 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.

[0358] 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.

[0359] 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.

[0360] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, and cyclohexyloxy.

[0361] As Rb 400 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0362] 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.

[0363] 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.

[0364] 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.

[0365] Examples of the branched alkyl group having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl and tert-butyl.

[0366] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0367] R 500 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.

[0368] 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.

[0369] 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.

[0370] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, and cyclohexyloxy.

[0371] As Rb 500 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0372] 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.

[0373] 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.

[0374] 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.

[0375] Examples of the branched alkyl group having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl and tert-butyl.

[0376] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0377] 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.

[0378] 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.

[0379] 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.

[0380] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, and cyclohexyloxy.

[0381] As Rb 800 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0382] 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.

[0383] 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.

[0384] 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.

[0385] Examples of the branched alkyl group having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl and tert-butyl.

[0386] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0387] 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.

[0388] 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.

[0389] 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.

[0390] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, and cyclohexyloxy.

[0391] As Rb 900 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0392] 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.

[0393] [Chemical formula 25]

[0394]

[0395] 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.

[0396] [Chemical formula 26]

[0397]

[0398] Specific examples of the diol unit (B3) include diol units (B3-1) to (B3-4), but the diol unit (B3) is not limited thereto.

[0399] [Chemical formula 27]

[0400]

[0401] Specific examples of the diol unit (B4) include diol units (B4-1) to (B4-7), but the diol unit (B4) is not limited thereto.

[0402] [Chemical formula 28]

[0403]

[0404] Specific examples of the diol unit (B5) include diol units (B5-1) to (B5-6), but the diol unit (B5) is not limited thereto.

[0405] [Chemical formula 29]

[0406]

[0407] Specific examples of the diol unit (B6) include diol units (B6-1) to (B6-4), but the diol unit (B6) is not limited thereto.

[0408] [Chemical formula 30]

[0409]

[0410] 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.

[0411] [Chemical formula 31]

[0412]

[0413] Specific examples of the diol unit (B8) include diol units (B8-1) to (B8-3), but the diol unit (B8) is not limited thereto.

[0414] [Chemical formula 32]

[0415]

[0416] The diol unit (B) contained in the polyester resin (1) may be one kind or two or more kinds.

[0417] 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.

[0418] When the mass ratio of the diol unit (B) is 25 mass % or more, peeling of the photosensitive 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.

[0419] When the mass ratio of the diol unit (B) is 80 mass % or less, the solubility in the coating solution for forming the photosensitive 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.

[0420] 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.

[0421] 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.

[0422] 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.

[0423] 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.

[0424] 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.

[0425] 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.

[0426] 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.

[0427] 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.

[0428] 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.

[0429] [Conductive substrate]

[0430] 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.

[0431] 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.

[0432] 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.

[0433] 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.

[0434] 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.

[0435] 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.

[0436] The conductive substrate may be subjected to a treatment using an acidic treatment liquid or a boehmite treatment.

[0437] The treatment based on the acidic treatment solution is implemented, for example, in the following manner. First, an acidic treatment solution containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The proportion of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment solution is, for example, in the range of 10 mass % to 11 mass % for phosphoric acid, in the range of 3 mass % to 5 mass % for chromic acid, and in the range of 0.5 mass % to 2 mass % for hydrofluoric acid, and the concentration of the total amount of these acids is preferably in the range of 13.5 mass % to 18 mass %. The treatment temperature is, for example, preferably 42° C. to 48° C. The film thickness of the film is, for example, preferably 0.3 μm to 15 μm.

[0438] 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.

[0439] [Undercoat]

[0440] The undercoat layer contains at least a binder resin and a peronone compound.

[0441] The binder resin of the lower coating layer is not particularly limited, and known resins can be used. Specifically, polyvinyl alcohol, polyvinyl acetal, polyethylene oxide, casein, polyamide, polyamic acid, polyurethane, polyimide, cellulose, gelatin, polyester, unsaturated polyester, polyolefin resin, methacrylic resin, acrylic resin, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, urea resin, phenolic resin, phenol-formaldehyde resin, melamine resin, alkyd resin, epoxy resin, resin containing hydrolyzable silyl group, condensation product of hydrolyzable silane, etc. can be cited.

[0442] The undercoat layer preferably contains at least polyurethane as a binder resin, for example.

[0443] The mass ratio of the polyurethane in the total amount of the binder resin in the undercoat layer is, for example, preferably 60 mass % or more, more preferably 70 mass % or more, further preferably 80 mass % or more, and may be 100 mass %.

[0444] Generally, polyurethanes are synthesized by the polyaddition reaction of polyfunctional isocyanates and polyols.

[0445] Examples of the polyfunctional isocyanate include diisocyanates such as methylene diisocyanate, ethylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 3,3'-dimethylbiphenylene diisocyanate, 4,4'-biphenylene diisocyanate, dicyclohexylmethane diisocyanate, and methylenebis(4-cyclohexyl isocyanate); isocyanurates obtained by trimerizing the above diisocyanates; and blocked isocyanates obtained by blocking the isocyanate groups of the above diisocyanates with a blocking agent. The polyfunctional isocyanate may be used alone or in combination of two or more.

[0446] Examples of the polyol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 2,2-dimethyl-1,3-propylene glycol, 1,2-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 3,3-dimethyl-1,2-butylene glycol, 2-ethyl-2-methyl-1,3-propylene glycol, 1,2-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,2-diethyl-1,3-propylene glycol, alcohol, 2,4-dimethyl-2,4-pentanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propanediol, 2,5-dimethyl-2,5-hexanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-cyclohexanedimethanol, hydroquinone, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol, poly(oxytetramethylene) glycol, 4,4'-dihydroxydiphenyl-2,2-propane, 4,4'-dihydroxyphenylsulfone and the like.

[0447] Examples of the polyol include polyester polyol, polycarbonate polyol, polycaprolactone polyol, polyether polyol, and polyvinyl butyral.

[0448] The polyol may be used alone or in combination of two or more.

[0449] The undercoat layer may contain other components in addition to the binder resin and the perinone compound. The other components will be described below.

[0450] The undercoat layer may also contain at least one of an organic acid metal salt and an organic metal complex. At least one of the organic acid metal salt and the organic metal complex contained in the undercoat layer may be, for example, an organic acid metal salt or an organic metal complex used as a urethane curing catalyst (i.e., a catalyst for the addition polymerization reaction of a polyfunctional isocyanate and a polyol) when forming the undercoat layer.

[0451] Examples of the metal constituting the organic acid metal salt or the organic metal complex include bismuth, aluminum, zirconium, zinc, cobalt, iron, nickel, copper, tin, platinum, palladium, etc. The organic acid of the organic acid metal salt is preferably a monocarboxylic acid, and the monocarboxylic acid is preferably octanoic acid, cyclohexane acid, or salicylic acid, and more preferably octanoic acid.

[0452] From the viewpoint of suppressing the increase of residual potential generated when repeatedly forming images, at least one of the organic acid metal salts and organic metal complexes contained in the undercoat layer is preferably at least one of the organic acid metal salts and organic metal complexes containing a metal selected from the group consisting of bismuth, aluminum, zirconium, zinc, cobalt, iron, nickel and copper, and more preferably at least one of the organic acid metal salts and organic metal complexes containing a metal selected from the group consisting of bismuth, aluminum and zirconium.

[0453] Examples of the organic acid metal salt or organic metal complex containing bismuth include bismuth octoate, bismuth cyclohexaneate, bismuth salicylate, and K-KAT348, K-KAT XC-C227, K-KAT XK-628, and K-KAT XK-640 manufactured by King Industry.

[0454] Examples of the organic acid metal salt or organic metal complex containing aluminum include aluminum octylate, aluminum naphthenate, aluminum salicylate, and K-KAT5218 manufactured by King Industry.

[0455] Examples of the organic acid metal salt or organic metal complex containing zirconium include zirconium octylate, zirconium naphthenate, zirconium salicylate, and K-KAT4205, K-KAT6212, and K-KATA209 manufactured by King Industry.

[0456] Examples of the organic acid metal salt or organic metal complex containing zinc include zinc octylate, zinc naphthenate, and zinc salicylate.

[0457] Examples of the organic acid metal salt or organic metal complex containing cobalt include cobalt octylate, cobalt naphthenate, and cobalt salicylate.

[0458] Examples of the organic acid metal salt or organic metal complex containing iron include iron octylate, iron naphthenate, and iron salicylate.

[0459] Examples of the organic acid metal salt or organic metal complex containing nickel include nickel octylate, nickel naphthenate, and nickel salicylate.

[0460] Examples of the organic acid metal salt or organic metal complex containing copper include copper octylate, copper naphthenate, and copper salicylate.

[0461] The organic acid metal salt and the organic metal complex may be used alone or in combination of two or more.

[0462] When the lower coating contains at least one of an organic acid metal salt and an organic metal complex, the total content of the organic acid metal salt and the organic metal complex relative to the total solid content of the lower coating is, for example, preferably from 0.001 mass % to 3 mass %, more preferably from 0.003 mass % to 2 mass %, further preferably from 0.01 mass % to 1 mass %, further preferably from 0.05 mass % to 0.5 mass %.

[0463] The undercoat layer may contain inorganic particles. Examples of the inorganic particles include a 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.

[0464] Examples of the inorganic particles having the above resistance value include metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles. Among them, zinc oxide particles are preferred.

[0465] Examples of inorganic particles other than the above include silica particles and metal titanate compound particles. Examples of metal titanate compound particles include strontium titanate particles, barium titanate particles, calcium titanate particles, and magnesium titanate particles.

[0466] The specific surface area of ​​the inorganic particles based on the BET method is preferably 10 m 2 / g or above.

[0467] 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).

[0468] 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.

[0469] Examples of the surface treatment agent include silane coupling agents, titanate coupling agents, aluminum coupling agents, surfactants, etc. For example, a silane coupling agent is preferred, and a silane coupling agent having an amino group is more preferred.

[0470] 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.

[0471] 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.

[0472] The surface treatment method using the surface treatment agent may be any known method, and may be either a dry method or a wet method. 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.

[0473] 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.

[0474] Examples of the electron accepting compound include 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 the like.

[0475] As the electron accepting compound, for example, a compound having an anthraquinone structure is preferred. As the compound having an anthraquinone structure, for example, a hydroxyanthraquinone compound, an aminoanthraquinone compound, an aminohydroxyanthraquinone compound, etc. are preferred, and specifically, for example, anthraquinone, alizarin, quinizarin, anthrarutin, purpurin, etc. are preferred.

[0476] 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.

[0477] 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.

[0478] The dry method is, for example, a method in which an electron accepting compound is directly added dropwise or an electron accepting compound dissolved in an organic solvent is added dropwise while stirring the inorganic particles by a mixer with a large shear force, and the electron accepting compound is attached to the surface of the inorganic particles by spraying with dry air or nitrogen. When the electron accepting compound is added dropwise or sprayed, it is preferably 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 temperature above 100°C. There is no particular limitation on sintering as long as the temperature and time at which the electrophotographic properties can be obtained.

[0479] 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 of the inorganic particles while stirring and heating in a solvent, and a method of removing the water content of the inorganic particles by azeotroping the inorganic particles with the solvent can be cited.

[0480] 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.

[0481] The content of the electron accepting compound is, for example, preferably 0.01 mass % to 20 mass % inclusive, and more preferably 0.01 mass % to 10 mass % inclusive, based on the inorganic particles.

[0482] In order to improve the charge retention, improve the electrical properties, improve the environmental stability and improve the image quality, the lower coating layer may also include various additives. As additives, amine compounds with an ionization potential of 5.4 eV or more and 5.9 eV or less, polycyclic condensation, azo-type electron-transmitting pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents and other known materials may be cited. As mentioned above, silane coupling agents are used for the surface treatment of inorganic particles, but can be further added to the lower coating layer as an additive.

[0483] 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.

[0484] 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.

[0485] 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.

[0486] Examples of the aluminum chelate compound include aluminum isopropoxide, monobutoxyaluminum diisopropoxide, aluminum butoxide, diethyl acetoacetate aluminum diisopropoxide, and tris(ethyl acetoacetate)aluminum.

[0487] These additives may be used alone or in the form of a mixture or polycondensate of a plurality of compounds.

[0488] The undercoat layer preferably has a Vickers hardness of 35 or more, for example.

[0489] 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 wavelength λ of the exposure laser used.

[0490] 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.

[0491] 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 adding the above-mentioned components to a solvent to form a coating film of a coating liquid for forming an undercoat layer, drying the coating film, and heating as necessary.

[0492] 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.

[0493] 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.

[0494] The violacetone compound (1) and the violacetone compound (2) are, for example, not easily soluble in an organic solvent, and therefore are preferably dispersed in an organic solvent. As the dispersion method, for example, a roller mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, a paint stirrer and the like known methods can be cited. When inorganic particles are added to the undercoat layer, for example, the inorganic particles are also preferably dispersed in an organic solvent by the same dispersion method.

[0495] 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.

[0496] From the viewpoint of penetration resistance, the average thickness of the undercoat layer is, for example, preferably 3 μm or more, more preferably 4 μm or more, and further preferably 5 μm or more.

[0497] From the viewpoint of suppressing an increase in residual potential during repeated use, the average thickness of the undercoat layer is, for example, preferably 50 μm or less, more preferably 40 μm or less, and further preferably 30 μm or less.

[0498] The average thickness of each layer of the photoreceptor is the arithmetic average of the values ​​measured by an electromagnetic film thickness meter, and the measurement locations are 12 locations in total at 90° scales along the circumferential direction, at the center and near both ends.

[0499] [Middle layer]

[0500] An intermediate layer may be provided between the undercoat layer and the photosensitive layer.

[0501] 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.

[0502] 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.

[0503] The compounds used in the intermediate layer may be used alone or as a mixture or polycondensate of a plurality of compounds.

[0504] Among them, the intermediate layer is preferably a layer containing an organic metal compound containing zirconium atoms or silicon atoms, for example.

[0505] 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 obtained by adding the above components to a solvent, drying the coating film, and heating as necessary.

[0506] 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.

[0507] The average thickness of the intermediate layer is preferably, for example, 0.1 μm or more and 3 μm or less.

[0508] [Charge Generation Layer]

[0509] 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.

[0510] 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.

[0511] Among them, in order to cope with laser exposure in the near-infrared region, as the charge generating material, for example, a metal phthalocyanine pigment or a metal-free phthalocyanine pigment is preferably used. Specifically, for example, at least one selected from the group consisting of hydroxygallium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine and oxytitanium phthalocyanine is preferred, hydroxygallium phthalocyanine and / or chlorogallium phthalocyanine is more preferred, and hydroxygallium phthalocyanine is further preferred.

[0512] 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.

[0513] Even when using an incoherent light source such as an LED or an organic EL image array whose central wavelength of light emission is within the range of 450nm to 780nm, the above-mentioned charge generating material can be used. However, from the viewpoint of resolution, when a photosensitive layer is used as a thin film of 20μm or less, the electric field intensity in the photosensitive layer becomes high, and the charge is reduced due to the injection of charges from the substrate, so that image defects called black spots are easily generated. This becomes significant when a charge generating material that easily generates dark current in a p-type semiconductor such as trigonal selenium and phthalocyanine pigment is used.

[0514] 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.

[0515] 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.

[0516] 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 1×1013 Ω·cm or more.

[0517] These binder resins may be used alone or in combination of two or more.

[0518] 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.

[0519] Other known additives may be contained in the charge generating layer.

[0520] 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 is formed by adding the above-mentioned components to a solvent, and the coating film is dried and heated 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 a condensed ring aromatic pigment or a perylene pigment is used as the charge generating material.

[0521] 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.

[0522] As a method for dispersing particles (e.g., charge generating material) in the coating liquid for forming the 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 roll 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 dispersed by liquid-liquid collision or liquid-wall collision under high pressure, and a penetration method in which the dispersion is dispersed by penetrating a fine flow path under high pressure, etc. can be cited.

[0523] When performing the dispersion, it is effective to set the average particle size of the charge generating material in the charge generating layer forming coating liquid to 0.5 μm or less, for example, preferably 0.3 μm or less, more preferably 0.15 μm or less.

[0524] 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.

[0525] The average thickness of the charge generating layer is, for example, preferably 0.1 μm or more and 5.0 μm or less, and more preferably 0.2 μm or more and 2.0 μm or less.

[0526] [Charge transport layer]

[0527] The charge transport layer is, for example, a layer containing a charge transport material and a binder resin. The charge transport layer may be a layer containing a polymer charge transport material.

[0528] 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.

[0529] As the polymer charge transport material, known chemical substances having charge transport properties such as poly-N-vinyl carbazole and polysilane can be cited. For example, polyester-based polymer charge transport materials are preferred. The polymer charge transport material can be used alone or in combination with a binder resin.

[0530] As charge transport materials or polymer charge transport materials, there can also be mentioned polycyclic aromatic compounds, aromatic nitro compounds, aromatic amine compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds (especially triphenylamine compounds), diamine compounds, oxadiazole compounds, carbazole compounds, organic polysilane compounds, pyrazoline compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, cyanide compounds, benzofuran compounds, aniline compounds, butadiene compounds and resins having groups derived from these substances. Specifically, paragraphs 0078 to 0080 of Japanese Patent Application Publication No. 2021-117377, paragraphs 0046 to 0048 of Japanese Patent Application Publication No. 2019-035900, paragraphs 0052 to 0053 of Japanese Patent Application Publication No. 2019-012141, paragraphs 0122 to 0134 of Japanese Patent Application Publication No. 2021-071565, and paragraphs 0136 to 0137 of Japanese Patent Application Publication No. 2021-0 Compounds described in paragraphs 0101 to 0110 of Japanese Patent Application No. 15223, paragraph 0116 of Japanese Patent Application No. 2013-097300, paragraphs 0309 to 0316 of International Publication No. 2019 / 070003, paragraphs 0103 to 0107 of Japanese Patent Application No. 2018-159087, and paragraphs 0102 to 0113 of Japanese Patent Application No. 2021-148818.

[0531] From the viewpoint of charge mobility, the charge transport material, for example, preferably includes at least one selected from the group consisting of a compound (C1) represented by the following formula (C1), a compound (C2) represented by formula (C2), a compound (C3) represented by formula (C3) and a compound (C4) represented by formula (C4).

[0532] [Chemical formula 33]

[0533] Formula (C1)

[0534] In formula (C1), Ar T1 ,Ar T2 and Ar T3 are independently aryl, -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 are independently a hydrogen atom, an alkyl group or an aryl group. T5 and R T6 When the aromatic groups are aromatic, the aromatic groups can be connected to each other through -C(R 51 )(R 52 )-and / or-C(R 61 )=C(R 62 )- is linked to a divalent group. 51 , R 52 , R 61 and R 62 Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0535] The group in formula (C1) may be substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

[0536] From the viewpoint of charge mobility, the compound (C1) preferably has at least one aromatic group or -C6H4-CH=CH-CH=C(R T7 )(R T8 ), more preferably a compound (C'1) represented by the following formula (C'1).

[0537] [Chemical formula 34]

[0538]

[0539] In formula (C'1), R T111 , R T112 , R T121 , R T122 , R T131 and R T132 Each of Tj1, Tj2, Tj3, Tk1, Tk2 and Tk3 is independently 0, 1 or 2.

[0540] [Chemical formula 35]

[0541] Formula (C2)

[0542] In formula (C2), R T201 , R T202 , R T211 and R T212 are each independently 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 or 2 carbon atoms, an aryl group, a -C(R T21 )=C(R T22 )(R T23 ) or -CH=CH-CH=C(R T24 )(R T25 ). T21 , R T22 , R T23 , R T24 and R T25 are independently a hydrogen atom, an alkyl group or an aryl group. T221 and R T222 Each of them is independently 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. Tm1, Tm2, ​​Tn1, and Tn2 are each independently 0, 1, or 2.

[0543] The group in formula (C2) may be substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

[0544] From the viewpoint of charge mobility, the compound (C2) preferably has at least one alkyl group, aryl group or -CH=CH-CH=C(R T24 )(R T225 ), more preferably a compound having two alkyl groups, aryl groups or -CH=CH-CH=C(RT24 )(R T25 ) compounds.

[0545] [Chemical formula 36]

[0546] Formula (C3)

[0547] In formula (C3), R T301 , R T302 , R T311 and R T312 are each independently 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 or 2 carbon atoms, an aryl group, a -C(R T31 )=C(R T32 )(R T33 ) or -CH=CH-CH=C(R T34 )(R T35 ). T31 , R T32 , R T33 , R T34 and R T35 are independently a hydrogen atom, an alkyl group or an aryl group. T321 , R T322 and R T331 Each of them is independently 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. To1, To2, Tp1, Tp2, Tq1, Tq2, and Tr1 are each independently 0, 1, or 2.

[0548] The group in formula (C3) may be substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

[0549] [Chemical formula 37]

[0550] Formula (C4)

[0551] In formula (C4), R T401 , R T402 , R T411 and R T412 are each independently 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 or 2 carbon atoms, an aryl group, a -C(R T41 )=C(R T42 )(R T43 ) or -CH=CH-CH=C(R T44 )(R T45). T41 , R T42 , R T43 , R T44 and R T45 are independently a hydrogen atom, an alkyl group or an aryl group. T421 , R T422 and R T431 Each of them is independently 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. Ts1, Ts2, Tt1, Tt2, Tu1, Tu2, and Tv1 are each independently 0, 1, or 2.

[0552] The group in formula (C4) may be substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

[0553] The content of the charge transport material contained in the charge transport layer is preferably, for example, 20% by mass or more and 70% by mass or less relative to the total mass of the charge transport layer.

[0554] The charge transport layer contains at least a polyester resin (1) as a binder resin.

[0555] The proportion of the polyester resin (1) in the total amount of the binder resin contained in the charge transport layer is, for example, preferably 40% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, particularly preferably 70% by mass or more.

[0556] When the polyester resin (1) is used in combination with other resins, the other resin used in combination is preferably, for example, a polycarbonate resin.

[0557] One embodiment of the charge transport layer contains polyester resin (1) and polycarbonate resin as binder resins. In this case, the mass ratio of the two resins is, for example, preferably polyester resin (1):polycarbonate resin=95:5 to 30:70, more preferably 95:5 to 40:60.

[0558] The mass ratio of the total of the polyester resin (1) and the polycarbonate resin in the charge transport layer is, for example, preferably 15 mass % to 80 mass %, more preferably 20 mass % to 75 mass %, further preferably 25 mass % to 70 mass %.

[0559] As the polycarbonate resin, for example, a polycarbonate resin having a continuous structural unit having an aromatic ring is preferred, and specific examples thereof include the polycarbonate resins used in the Examples described below.

[0560] The charge transport layer may include other binder resins other than polyester resin (1) and polycarbonate resin. As other binder resins, polyester resins other than polyester resin (1), methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl acetate resins, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, silicone resins, silicone alkyd resins, phenolic-formaldehyde resins, styrene-alkyd resins, poly-N-vinyl carbazole, polysilane, etc., may be cited. These binder resins are used alone or in combination.

[0561] The charge transport layer may contain other known additives, such as antioxidants, leveling agents, defoaming agents, fillers, and viscosity modifiers.

[0562] The charge transport layer can be formed by any known method without particular limitation, but can be formed by, for example, forming a coating film of a charge transport layer-forming coating liquid obtained by adding the above components to a solvent, drying the coating film, and heating as necessary.

[0563] 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.

[0564] 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.

[0565] From the viewpoint of photosensitivity and wear life of the photoreceptor, the average thickness of the charge transport layer is, for example, preferably 20 μm or more, more preferably 22 μm or more, and further preferably 25 μm or more.

[0566] From the viewpoint of residual potential, the average thickness of the charge transport layer is, for example, preferably 50 μm or less, more preferably 47 μm or less, and further preferably 45 μm or less.

[0567] [Single-layer photosensitive layer]

[0568] The single-layer photosensitive layer (charge generating layer / charge transporting layer) is a layer containing a charge generating material, a charge transporting material, a binder resin, and other additives as required. These materials are the same as those described for the charge generating layer and the charge transporting layer.

[0569] The single-layer type photosensitive layer contains at least the polyester resin (1) as a binder resin.

[0570] The proportion of the polyester resin (1) in the total amount of the binder resin contained in the single-layer photosensitive layer is, for example, preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, particularly preferably 90% by mass or more.

[0571] When the polyester resin (1) is used in combination with other resins, the other resin used in combination is preferably, for example, a polycarbonate resin.

[0572] One embodiment of the single-layer photosensitive layer contains polyester resin (1) and polycarbonate resin as binder resins. In this case, the mass ratio of the two resins is, for example, preferably polyester resin (1): polycarbonate resin = 95:5 to 30:70, more preferably 95:5 to 40:60.

[0573] The mass ratio of the total of the polyester resin (1) and the polycarbonate resin in the single-layer photosensitive layer is, for example, preferably 15 mass % to 80 mass %, more preferably 20 mass % to 75 mass %, further preferably 25 mass % to 70 mass %.

[0574] As the polycarbonate resin, for example, a polycarbonate resin having a continuous structural unit having an aromatic ring is preferred, and specific examples thereof include the polycarbonate resins used in the Examples described below.

[0575] In the single-layer photosensitive layer, the content of the charge generating material may be, for example, 0.1 mass % to 10 mass % inclusive, and preferably 0.8 mass % to 5 mass % inclusive, based on the total solid content.

[0576] The content of the charge transport material contained in the single-layer photosensitive layer is preferably, for example, 40% by mass or more and 60% by mass or less relative to the total solid content.

[0577] 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.

[0578] From the viewpoint of photosensitivity and abrasion life of the photoreceptor, the average thickness of the single-layer photosensitive layer is, for example, preferably 20 μm or more, more preferably 22 μm or more, and further preferably 25 μm or more.

[0579] From the viewpoint of residual potential, the average thickness of the single-layer photosensitive layer is, for example, preferably 50 μm or less, more preferably 47 μm or less, and further preferably 45 μm or less.

[0580] [Protective layer]

[0581] 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.

[0582] 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).

[0583] 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)

[0584] 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)

[0585] 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.

[0586] The chain polymerizable group is not particularly limited as long as it is a functional group capable of free radical polymerization, and is, for example, a functional group having a group containing at least a carbon double bond. Specifically, a group containing at least one selected from vinyl, vinyl ether, vinyl thioether, phenylvinyl, vinylphenyl, acryloyl, methacryloyl, and derivatives thereof may be cited. Among them, since it has excellent reactivity, the chain polymerizable group is preferably a group containing at least one selected from vinyl, phenylvinyl, vinylphenyl, acryloyl, methacryloyl, and derivatives thereof.

[0587] 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.

[0588] 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.

[0589] Other known additives may be contained in the protective layer.

[0590] 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 obtained by adding the above components to a solvent, drying the coating film, and performing a curing treatment such as heating as necessary.

[0591] 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.

[0592] The protective layer-forming coating liquid may be a solvent-free coating liquid.

[0593] 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.

[0594] The average thickness of the protective layer is, for example, preferably 1 μm or more and 20 μm or less, and more preferably 2 μm or more and 10 μm or less.

[0595] <Image forming apparatus, process cartridge>

[0596] 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, and a transfer device for transferring the toner image to the surface of a recording medium. As the electrophotographic photoreceptor, the electrophotographic photoreceptor according to the present embodiment is applicable.

[0597] The image forming device involved in this embodiment is applicable to the following well-known image forming devices: a device equipped with a fixing device for fixing the toner image transferred to the surface of a recording medium; a device using a direct transfer method for directly transferring the toner image formed on the surface of an electrophotographic photosensitive body to the recording medium; a device using an intermediate transfer method for transferring the 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; a device equipped with a cleaning device for cleaning the surface of the electrophotographic photosensitive body after transferring the toner image but before charging; a device equipped with a static elimination device for removing static electricity by irradiating the surface of the electrophotographic photosensitive body with static elimination light after transferring the toner image and before charging; and a device equipped with an electrophotographic photosensitive body heating component for increasing the temperature of the electrophotographic photosensitive body and lowering the relative temperature, etc.

[0598] 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 having a toner image transferred on its surface, a primary transfer device for transferring the toner image formed on the surface of the electronic photographic photosensitive body to the surface of the intermediate transfer body, and a secondary transfer device for secondary transferring the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

[0599] 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.

[0600] 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.

[0601] 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.

[0602] Figure 3 It is a schematic configuration diagram showing an example of the image forming apparatus according to the present embodiment.

[0603] 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.

[0604] 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.

[0605] 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.

[0606] Hereinafter, each structure of the image forming apparatus according to the present embodiment will be described.

[0607] -Electrified Devices-

[0608] As the charging device 8, for example, a contact type charging device such as a charging roller, a charging brush, a charging film, a charging rubber blade, a charging hose, etc. using conductive or semi-conductive charging can be used. In addition, a non-contact type roller charging device, a scorotron charging device or a corotron charging device using corona discharge, etc., which are known per se, can also be used.

[0609] -Exposure device-

[0610] 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.

[0611] -Developing device-

[0612] 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.

[0613] 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.

[0614] -Cleaning device-

[0615] 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.

[0616] -Transfer device-

[0617] 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.

[0618] -Intermediate transfer body-

[0619] 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.

[0620] Figure 4It is a schematic configuration diagram showing another example of the image forming apparatus according to the present embodiment.

[0621] 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.

[0622] Example

[0623] 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.

[0624] In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0625] In the following description, unless otherwise specified, synthesis, production, treatment, measurement, etc. were performed at room temperature (25° C.±3° C.).

[0626] <Synthesis of polyester resin (1)>

[0627] Polyester resins (1-1) to (1-6) were synthesized. In the synthesis of all these resins, polymerization was carried out in the presence of 4-tert-butylphenol as a terminal blocking agent to block the terminals of the polyester resins.

[0628] Table 1 shows the units and composition constituting the polyester resin (1).

[0629] A2-3 and the like described in Table 1 are specific examples of the dicarboxylic acid unit (A) described above.

[0630] B1-4 and the like described in Table 1 are specific examples of the diol unit (B) already described.

[0631] [Table 1]

[0632]

[0633] <Manufacturing of a photoreceptor having a laminated photosensitive layer>

[0634] [Example S1]

[0635] -Formation of lower coating layer-

[0636] 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.

[0637] 20 parts of blocked isocyanate (SUMIDUR BL3175, manufactured by Sumitomo Bayer Urethane Co., Ltd., solid content 75%) and 7.5 parts of butyral resin (polyvinyl butyral, S-LEC BL-1, manufactured by SEKISUI CHEMICAL CO., LTD.) were dissolved in 150 parts of methyl ethyl ketone. 34 parts of a mixture (mass ratio 50:50) of a violet ketone compound (1-1) and a violet ketone compound (2-1) were mixed in the solution, and dispersed for 10 hours using glass beads with a diameter of 1 mm by a sand mill to obtain a dispersion. 0.005 parts by mass of bismuth carboxylate (K-KAT XK-640, manufactured by KING INDUSTRY) and 2 parts of silicone resin particles (Tospearl145, manufactured by Momentive performance Materials Inc.) were added to the dispersion to obtain a coating solution for forming an undercoat layer. The coating liquid was dip-coated on a conductive substrate, and dried and cured at 160° C. for 60 minutes to form an undercoat layer. The average thickness of the undercoat layer is shown in Table 2.

[0638] -Formation of Charge Generation Layer-

[0639] 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 a sand mill using glass beads having a diameter of 1 mm. 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 solution for forming a charge generating layer. The coating solution was dip-coated on the undercoat layer and dried at room temperature to form a charge generating layer having an average thickness of 0.18 μm.

[0640] -Formation of Charge Transport Layer-

[0641] 17 parts of polyester resin (1-1) as a binder resin, 43 parts of polycarbonate resin (1) and 40 parts of CTM-1 as a charge transport material were dissolved in 270 parts of tetrahydrofuran and 30 parts of toluene to obtain a coating liquid for forming a charge transport layer. The coating liquid was dip-coated on the charge generating layer and dried at 145°C for 30 minutes to form a charge transport layer with an average thickness of 34 μm.

[0642] [Chemical formula 38]

[0643]

[0644] In the formula, 15 and 85 represent the copolymerization molar ratio (mol %).

[0645] [Chemical formula 39]

[0646]

[0647] [Examples S2 to S23, Comparative Examples SC1 to SC4]

[0648] The type and mass ratio of the binder resin of the undercoat layer, the type and mass ratio of the purple ketone compound of the undercoat layer, the type of the organic acid metal salt or the organic metal complex of the undercoat layer, the average thickness of the undercoat layer, the type of the charge generating material of the charge generating layer, the type and mass ratio of the binder resin of the charge transport layer, the type and mass ratio of the charge transport material of the charge transport layer, and the average thickness of the charge transport layer were changed to the specifications described in Tables 2 and 3. Except for this, each photoreceptor was prepared in the same manner as Example S1.

[0649] In Example S8, the solvent of the coating liquid for forming an undercoat layer was changed from methyl ethyl ketone to a mixed solvent of isopropyl alcohol and water (mass ratio 60:40).

[0650] The polyolefin (1) used in Example S8 was a resin obtained by hydrolyzing the maleic anhydride portion of BONDINE HX-8290 (Sumitomo Chemical Industry Company Limited, ethylene-acrylate-maleic anhydride terpolymer) to obtain a triethylamine salt. Specifically, the synthesis was performed as follows.

[0651] 75 parts of BONDINE HX-8290, 90 parts of isopropyl alcohol, 1.2 equivalents of triethylamine to the carboxyl groups of maleic anhydride in the resin, and 200 parts of distilled water were added to a reaction container, and heated at 145° C. for 60 minutes while stirring. Then, the mixture was cooled to room temperature while stirring, and pressure filtered was performed using a 300-mesh stainless steel filter to obtain an aqueous dispersion of polyolefin (1) having a solid content concentration of 20%.

[0652] In Example S9, the solvent of the coating liquid for forming an undercoat layer was changed from methyl ethyl ketone to a mixed solvent of methanol and isopropyl alcohol (mass ratio 70:30).

[0653] The polyamide (1) used in Example S9 is Amilan TM CM8000 (TORAY INDUSTRIES, INC.).

[0654] The "hydroxy Ga phthalocyanine" described in Table 3 and Table 6 is hydroxy gallium phthalocyanine.

[0655] "Ti phthalocyanine" described in Table 3 is titanium phthalocyanine.

[0656] The imide compound (A), the polyester resin (C1), and the charge transport materials CTM-2 to CTM-4 are the following compounds, respectively.

[0657] [Chemical formula 40]

[0658]

[0659] [Chemical formula 41]

[0660]

[0661] Wherein, 25, 25, 50 represent copolymerization molar ratio (mol %).

[0662] [Chemical formula 42]

[0663]

[0664] <Manufacturing of a photoreceptor having a single-layer photosensitive layer>

[0665] [Photoreceptor T1]

[0666] -Formation of lower coating layer-

[0667] The undercoat layer was formed on the conductive substrate in the same manner as in Example S1. The average thickness of the undercoat layer is shown in Table 5.

[0668] -Formation of a single-layer photosensitive layer-

[0669] 52.75 parts of polyester resin (1-1) as a binder resin, 1.25 parts of V-type hydroxygallium phthalocyanine (having diffraction peaks at positions of at least 7.3°, 16.0°, 24.9°, and 28.0° in the X-ray diffraction spectrum using CuKα characteristic X-rays) as a charge generating material, 7.8 parts of ETM-1, an electron transport material, 38.2 parts of CTM-1, a charge transport material (mass ratio of ETM-1 to CTM-1 is 17:83), 175 parts of tetrahydrofuran and 75 parts of toluene as a solvent were mixed, and dispersion treatment was performed for 4 hours using a sand mill using glass beads with a diameter of 1 mm to obtain a coating liquid for forming a photosensitive layer. The coating liquid was dip-coated on the undercoat layer, and dried and cured at a temperature of 110°C for 40 minutes to form a single-layer photosensitive layer with an average thickness of 34 μm.

[0670] [Chemical formula 43]

[0671]

[0672] [Photoreceptors T2 to T6, Photoreceptors TC1 to TC3]

[0673] Each photosensitive body was manufactured in the same manner as photosensitive body T1 except that the type of the binder resin of the undercoat layer, the type of the violacetone compound of the undercoat layer, the type of the binder resin of the single-layer photosensitive layer, the type of the charge transport material of the single-layer photosensitive layer, and the average thickness of the single-layer photosensitive layer were changed to the specifications listed in Tables 5 and 6.

[0674] <Photoreceptor performance evaluation>

[0675] The photoreceptor of each example or each comparative example was mounted on an image forming apparatus ApeosC7070 manufactured by FUJIFILM Business Innovation.

[0676] In order to measure the surface potential of the photoreceptor, a probe connected to a surface potentiometer (TREQ334 manufactured by TREQ INC.) was placed at the center of the photoreceptor and 1 mm away from the surface of the photoreceptor.

[0677] Under an environment of temperature 28° C. and relative humidity 85%, the charging conditions and exposure conditions of the photoreceptor of Example S5 (before printing evaluation) were adjusted so that the charging potential and the potential after exposure became the following setting A and setting B. Under the same charging conditions and exposure conditions, the printing evaluation described below was also performed on other photoreceptors.

[0678] Setting A: Surface potential after charging is -700V, and surface potential after exposure is -240V

[0679] Setting B: Surface potential after charging is -800V, and surface potential after exposure is -210V

[0680] [Maintainability of Charged Potential]

[0681] Under the conditions of temperature 28°C and relative humidity 85%, 70,000 sheets of halftone images with an image density of 30% were output on A3 size paper under the conditions of setting A and setting B. The difference between the charge potential when the first sheet was output and the charge potential when the 70,000th sheet was output was calculated and classified as follows. The evaluation results are shown in Tables 4 and 7.

[0682] A: The difference in charged potential is less than 20V

[0683] B: The difference in charge potential is greater than 20V and less than 30V

[0684] C: The difference in charge potential is 30V or more and less than 40V

[0685] D: The difference in charge potential is 40V or more and less than 50V

[0686] E: The difference in charge potential is 50V or more

[0687] [Maintainability of potential after exposure]

[0688] Under the conditions of temperature 28°C and relative humidity 85%, 70,000 sheets of halftone images with an image density of 30% were output on A3 size paper under the conditions of setting A and setting B. The difference between the residual potential after the first sheet was output and exposed and the residual potential after the 70,000th sheet was output and exposed was calculated and classified as follows. The evaluation results are shown in Tables 4 and 7.

[0689] A: The difference in residual potential is less than 30V

[0690] B: The difference in residual potential is 30V or more and 40V

[0691] C: The difference in residual potential is 40V or more and 50V

[0692] D: The difference in residual potential is 50V or more and 60V

[0693] E: The difference in residual potential is 60V or more

[0694] [Burning and sticking]

[0695] At 28°C and 85% relative humidity, 30,000 sheets of A3 size paper were formed under setting A and setting B. Figure 5 After the grid-like chart image (cyan) shown in (A), a whole-surface halftone image (cyan) with an image density of 20% was output continuously. The appearance of the grid-like image (burn-in ghost) on the whole-surface halftone image was observed with the naked eye and classified as follows. The evaluation results are shown in Tables 4 and 7.

[0696] A: If Figure 5 As shown in (B), no grid-like image was confirmed.

[0697] B: If Figure 5 As shown in (C), a grid-like image is slightly confirmed.

[0698] C: Figure 5 As shown in (D), a grid-like image is clearly confirmed.

[0699] [Table 2]

[0700]

[0701] [Table 3]

[0702]

[0703] [Table 4]

[0704]

[0705] [Table 5]

[0706]

[0707] [Table 6]

[0708]

[0709] [Table 7]

[0710]

[0711] 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.

[0712] (1) An electrophotographic photoreceptor comprising a conductive substrate, an undercoat layer disposed on the conductive substrate, and a photosensitive layer disposed on the undercoat layer, wherein:

[0713] The undercoat layer contains a binder resin and at least one perinone compound selected from the group consisting of a compound represented by formula (1) and a compound represented by formula (2).

[0714] The photosensitive layer contains a polyester resin (1) having at least one dicarboxylic acid unit (A) selected from the group consisting of 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), and a diol unit (B) represented by the formula (B),

[0715] The mass ratio of the polyester resin (1) in the photosensitive layer is 15 mass % or more.

[0716] (2) The electrophotographic photoreceptor according to (1), wherein

[0717] The mass ratio of the perirone compound in the undercoat layer is 30 mass % or more and 90 mass % or less.

[0718] (3) The electrophotographic photoreceptor according to (1) or (2), wherein

[0719] The undercoat layer contains polyurethane.

[0720] (4) The electrophotographic photoreceptor according to any one of (1) to (3), wherein

[0721] The undercoat layer has an average thickness of 5 μm or more and 30 μm or less.

[0722] (5) The electrophotographic photoreceptor according to any one of (1) to (4), wherein

[0723] The photosensitive layer further contains a polycarbonate resin.

[0724] (6) The electrophotographic photoreceptor according to any one of (1) to (5), wherein

[0725] The polyester resin (1) comprises at least one diol unit (B) selected from the group consisting of a diol unit (B1) represented by formula (B1), a diol unit (B2) represented by formula (B2), a diol unit (B3) represented by formula (B3), a diol unit (B4) represented by formula (B4), a diol unit (B5) represented by formula (B5), a diol unit (B6) represented by formula (B6), a diol unit (B7) represented by formula (B7) and a diol unit (B8) represented by formula (B8).

[0726] (7) The electrophotographic photoreceptor according to any one of (1) to (6), wherein

[0727] The photosensitive layer contains gallium phthalocyanine as a charge generating material.

[0728] (8) A process cartridge comprising the electrophotographic photoreceptor according to any one of (1) to (7),

[0729] The process cartridge is attachable to and detachable from the image forming apparatus.

[0730] (9) An image forming apparatus comprising:

[0731] The electrophotographic photoreceptor according to any one of (1) to (7);

[0732] A charging device for charging the surface of the electrophotographic photoreceptor;

[0733] An electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor;

[0734] 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; and

[0735] The transfer device transfers the toner image to the surface of a recording medium.

[0736] According to the invention involved in (1), (3), (5), (6) or (7), there is provided an electronic photographic photosensitive body which has less difference in electrical properties at the beginning and end of repeated image formation and is less likely to produce burn-in ghosting in the image, compared with the case where the mass proportion of the polyester resin (1) in the photosensitive layer is less than 15 mass %, and which realizes these over a wider set range involving the intensity of charging and exposure.

[0737] According to the invention involved in (2), there is provided an electronic photographic photoreceptor which has less difference in electrical characteristics at the beginning and end of repeated image formation and is less likely to produce burn-in ghosting in the image, compared with the case where the mass proportion of the violacetone compound in the lower coating layer is less than 30 mass % or exceeds 90 mass %, and which realizes these over a wider set range involving the intensity of charging and exposure.

[0738] According to the invention involved in (4), there is provided an electronic photographic photosensitive body which has less difference in electrical properties at the beginning and end of repeated image formation and is less likely to produce burn-in ghosting in the image, compared with the case where the average thickness of the lower coating layer is less than 5 μm or greater than 30 μm, and which realizes these characteristics over a wider set range involving the intensity of charging and exposure.

[0739] According to the invention involved in (8), there is provided a processing box having the following electronic photographic photosensitive body, that is, compared with the case where the mass proportion of the polyester resin (1) in the photosensitive layer is less than 15 mass%, at the initial and final stages of repeated image formation, the difference in electrical characteristics is less, and it is less likely to produce burn-in ghosting in the image, and the electronic photographic photosensitive body realizes these over a wider set range involving the intensity of charging and exposure.

[0740] According to the invention involved in (9), there is provided an image forming device having the following electronic photographic photosensitive body, that is, compared with the case where the mass proportion of the polyester resin (1) in the photosensitive layer is less than 15 mass %, at the initial and final stages of repeated image formation, the difference in electrical characteristics is less, and it is less likely to produce burn-in ghosting in the image, and the electronic photographic photosensitive body realizes these over a wider set range involving the intensity of charging and exposure.

[0741] 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, an undercoat layer disposed on the conductive substrate, and a photosensitive layer disposed on the undercoat layer, wherein: The undercoat layer contains a binder resin and at least one perirone compound selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2). The photosensitive layer contains a polyester resin (1) having at least one dicarboxylic acid unit (A) selected from the group consisting of a dicarboxylic acid unit (A2) represented by the following formula (A2), a dicarboxylic acid unit (A3) represented by the following formula (A3) and a dicarboxylic acid unit (A4) represented by the following formula (A4), and a diol unit (B) represented by the following formula (B). The mass ratio of the polyester resin (1) in the photosensitive layer is 15 mass % or more, [Chemical formula 1] Formula (1 Formula (2) In formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom, and R 11 With R 12 , R 12 With R 13 and R 13 With R 14 can be independently bonded to each other to form a ring, R 15 With R 16 , R 16 With R 17 and R 17 With R 18 may independently bond to each other to form a ring, In formula (2), R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 and R 28 Each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group or a halogen atom, and R 21 With R 22 , R 22 With R 23 and R 23 With R 24 can be independently bonded to each other to form a ring, R 25 With R 26 , R 26 With R 27 and R 27 With R 28 may independently bond to each other to form a ring, [Chemical formula 2] Formula (A2) Formula (A3) Formula (A4) Formula (B) 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 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 (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.

2. The electrophotographic photoreceptor according to claim 1, wherein The mass ratio of the perirone compound in the undercoat layer is 30 mass % or more and 90 mass % or less.

3. The electrophotographic photoreceptor according to claim 1 or 2, wherein The undercoat layer contains polyurethane.

4. The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein The undercoat layer has an average thickness of 5 μm or more and 30 μm or less.

5. The electrophotographic photoreceptor according to any one of claims 1 to 4, wherein The photosensitive layer further contains a polycarbonate resin.

6. The electrophotographic photoreceptor according to any one of claims 1 to 5, wherein The polyester resin (1) comprises at least one diol unit (B) 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.

7. The electrophotographic photoreceptor according to any one of claims 1 to 6, wherein The photosensitive layer contains gallium phthalocyanine as a charge generating material.

8. A process cartridge comprising the electrophotographic photoreceptor according to any one of claims 1 to 7, The process cartridge is attachable to and detachable from the image forming apparatus.

9. An image forming apparatus comprising: The electrophotographic photoreceptor according to any one of claims 1 to 7; 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 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; and The transfer device transfers the toner image to the surface of a recording medium.

Images