Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Abstract

The invention provides an electrophotographic photoreceptor, a process cartridge, and an image forming apparatus. The electrophotographic photoreceptor includes: a conductive substrate; and a laminated photosensitive layer disposed on the conductive substrate and having a charge generation layer and a charge transport layer, in which the charge transport layer contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B), and the charge generation layer contains chlorogallium phthalocyanine as a charge generation material. The value of the content of the binder resin / the total content of the binder resin and the charge generating material in the charge generating layer is greater than 0.4 and less than 0.7. [Chemical Formula 1] Formula ((A) Formula (B)

Description

Technical Field

[0001] This invention relates to an electrophotographic photosensitive element, a processing cartridge, and an image forming apparatus. Background Technology

[0002] Patent Document 1 discloses an electrophotographic photosensitive material having a charge generation layer and a charge transport layer sequentially on a support. At least one of the binder resins in the charge transport layer is a polyarylate resin, and the film thickness of the charge transport layer is 28 μm or more. The electrophotographic photosensitive material is characterized in that the charge generation layer contains gallium phthalocyanine, and the charge transport layer contains 5% by mass and less than 40% by mass of antioxidant relative to the total mass of the binder resin in the charge transport layer.

[0003] Patent document 2 discloses an electrophotographic photosensitive material having a conductive substrate and a stacked photosensitive layer disposed on the conductive substrate having a charge generation layer and a charge transport layer. The charge transport layer contains a charge transport material, a polyester resin and a polycarbonate resin, and the polyester resin contains a polyester resin with a specific structure.

[0004] Patent document 3 discloses a layered electrophotographic photosensitive material having at least two layers, namely a charge generation layer and a charge transport layer, on a conductive support. The electrophotographic photosensitive material is characterized in that the charge generation layer contains phthalocyanine pigment and a polyarylate resin with a specific structure.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-164936

[0006] Patent Document 2: Japanese Patent Application Publication No. 2024-11918

[0007] Patent Document 3: Japanese Patent Application Publication No. 2003-202683 Summary of the Invention

[0008] The objective of this invention is to provide an electrophotographic photosensitive material with excellent suppression of localized deterioration of electrical properties after long-term printing, compared to a case where the charge transport layer contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B), the charge generation layer contains gallium chlorophthalocyanine as a charge generation material, and the ratio of the content of the binder resin in the charge generation layer to the total content of the binder resin and the charge generation material is 0.4 or less or 0.7 or more.

[0009] Solutions to the aforementioned problem include the following approaches.

[0010] <1> An electrophotographic photosensitive material comprising: a conductive substrate; and a stacked photosensitive layer disposed on the conductive substrate and having a charge generating layer and a charge transport layer, wherein the charge transport layer contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B), the charge generating layer contains gallium chlorophthalocyanine as a charge generating material, and the content of the binder resin in the charge generating layer / the total content of the binder resin and the charge generating material is greater than 0.4 and less than 0.7.

[0011] [Chemical Formula 1]

[0012]

[0013] In equation (A), Ar A1 and Ar A2 Each is an aromatic ring that can have substituents, L A It is a single bond or a divalent linker, n A1 It can be 0, 1, or 2.

[0014] In equation (B), Ar B1 and Ar B2 Each is an aromatic ring that can have substituents, L B It is a single bond, an oxygen atom, a sulfur atom, or -C(Rb) 1 (Rb) 2 )-,n B1 It can be 0, 1, or 2. Rb 1 and Rb 2 Rb is independently composed of hydrogen atoms, an alkyl group having 1 or more but less than 20 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an aralkyl group having 7 or more but less than 20 carbon atoms. 1 With Rb 2 They can bond together to form cyclic alkyl groups.

[0015] <2> According to the electrophotographic photosensitive material described in <1>, the content of the adhesive resin in the charge-generating layer / the total content of the adhesive resin and the charge-generating material is greater than 0.43 and less than 0.60.

[0016] <3> The electrophotographic photosensitive material according to <1> or <2>, wherein the dicarboxylic acid unit represented by formula (A) comprises at least one selected from the group consisting of the dicarboxylic acid unit (A1) represented by formula (A2), the dicarboxylic acid unit (A3) represented by formula (A4), the dicarboxylic acid unit (A5) represented by formula (A5).

[0017] [Chemical Formula 2]

[0018]

[0019] In equation (A1), n 101 n is an integer greater than or equal to 0 and less than or equal to 4. 101 Ra 101 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0020] In equation (A2), n 201 and n 202 Each of the following is an independent integer greater than 0 and less than 4, n 201 Ra 201 and n 202 Ra 202 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0021] In equation (A3), n 301 and n 302 Each of the following is an independent integer greater than 0 and less than 4, n 301 Ra 301 and n 302 Ra 302 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0022] In equation (A4), n 401 n is an integer greater than 0 and less than 6. 401 Ra 401 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0023] In equation (A5), n 501 n 502 and n 503 Each of the following is an independent integer greater than 0 and less than 4, n 501 Ra 501 n 502 Ra 502 and n 503 Ra 503 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0024] <4> The electrophotographic photosensitive unit according to any one of <1> to <3>, wherein the diol unit represented by formula (B) comprises at least one selected from the group consisting of the diol unit (B1) represented by formula (B1), the diol unit (B2) represented by formula (B2), the diol unit (B3) represented by formula (B3), the diol unit (B4) represented by formula (B4), the diol unit (B5) represented by formula (B5), the diol unit (B6) represented by formula (B6), the diol unit (B7) represented by formula (B7), and the diol unit (B8) represented by formula (B8).

[0025] [Chemical Formula 3]

[0026]

[0027] [Chemical Formula 4]

[0028]

[0029] In equation (B1), Rb 101 Branched alkyl groups with 4 or more but less than 20 carbon atoms, Rb 201 Rb is an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms. 401 、Rb 501 、Rb 801 and Rb 901 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0030] In equation (B2), Rb 102 Rb is a straight-chain alkyl group with 4 or more but less than 20 carbon atoms. 202 Rb is an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms. 402 、Rb 502 、Rb 802 and Rb 902 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0031] In equation (B3), Rb 113 and Rb 213 Each of the following is independently a hydrogen atom, a straight-chain alkyl group having 1 or more but less than 3 carbon atoms, an alkoxy group having 1 or more but less than 4 carbon atoms, or a halogen atom, where d is an integer between 7 and 15, and Rb 403 、Rb 503 、Rb 803 and Rb 903Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0032] In equation (B4), Rb 104 and Rb 204 Each is independently an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms, Rb 404 、Rb 504 、Rb 804 and Rb 904 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0033] In equation (B5), Ar 105 Rb is an aryl group having 6 or more but less than 12 carbon atoms, or an aralkyl group having 7 or more but less than 20 carbon atoms. 205 Rb is an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms. 405 、Rb 505 、Rb 805 and Rb 905 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0034] In equation (B6), Rb 116 and Rb 216 Each of the following is independently a hydrogen atom, a straight-chain alkyl group having 1 or more but less than 3 carbon atoms, an alkoxy group having 1 or more but less than 4 carbon atoms, or a halogen atom, where e is an integer of 4 or more but less than 6, and Rb 406 、Rb 506 、Rb 806 and Rb 906 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0035] In equation (B7), Rb 407 、Rb 507 、Rb 807 and Rb 907 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0036] In equation (B8), Rb 408 、Rb 508 、Rb 808 and Rb 908 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0037] <5> The electrophotographic photosensitive material according to any one of <1> to <4>, wherein the binding resin in the charge generating layer is a vinyl acetate resin or a polyvinyl butyral resin.

[0038] <6> The electrophotographic photosensitive material according to any one of <1> to <5>, wherein the adhesive resin in the charge generating layer is a vinyl chloride-vinyl acetate copolymer or a polyvinyl butyral resin.

[0039] <7> The electrophotographic photosensitive material according to any one of <1> to <6>, wherein the charge transport layer further comprises polycarbonate resin.

[0040] <8> A processing cartridge comprising any one of <1> to <7> of an electrophotographic photosensitive element, said processing cartridge being detachable from an image forming apparatus.

[0041] <9> An image forming apparatus comprising: an electrophotographic photoreceptor as described in any one of <1> to <7>; a charging device for charging the surface of the electrophotographic photoreceptor; an electrostatic latent image forming apparatus for forming an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; a developing apparatus for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developing agent containing a toner to form a toner image; and a transfer apparatus for transferring the toner image onto the surface of a recording medium.

[0042] Invention Effects

[0043] According to the invention described in <1>, compared to a case where the charge transport layer contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B), and the charge generation layer contains gallium chlorophthalocyanine as a charge generation material, and the content of the binder resin in the charge generation layer / the total content of the binder resin and the charge generation material is 0.4 or less or 0.7 or more, an electrophotographic photosensitive material with excellent suppression of local deterioration of electrical properties after long-term printing is provided.

[0044] According to the invention described in <2>, compared to cases where the content of the adhesive resin in the charge-generating layer / the total content of the adhesive resin and the charge-generating material is 0.43 or less or 0.60 or more, an electrophotographic photosensitive material with superior ability to suppress local deterioration of electrical properties after long-term printing is provided.

[0045] According to the invention described in <3>, compared to the case where the dicarboxylic acid unit represented by formula (A) does not contain at least one selected from the group consisting of the dicarboxylic acid unit (A1) represented by formula (A2), the dicarboxylic acid unit (A3) represented by formula (A4), the dicarboxylic acid unit (A4) represented by formula (A5), and the dicarboxylic acid unit (A5) represented by formula (A5), an electrophotographic photosensitive material with superior local deterioration inhibition of electrical properties after long-term printing is provided.

[0046] According to the invention described in <4>, compared to the case where the diol unit represented by formula (B) does not contain at least one selected from the group consisting of diol unit (B1) represented by formula (B1), diol unit (B2) represented by formula (B2), diol unit (B3) represented by formula (B3), diol unit (B4) represented by formula (B4), diol unit (B5) represented by formula (B5), diol unit (B6) represented by formula (B6), diol unit (B7) represented by formula (B7) and diol unit (B8) represented by formula (B8), an electrophotographic photosensitive material with superior local deterioration suppression of electrical properties after long-term printing is provided.

[0047] According to the invention described in <5>, compared with the case where the adhesive resin in the charge-generating layer is a polyester resin, an electrophotographic photosensitive material with superior ability to suppress local deterioration of electrical properties after long-term printing is provided.

[0048] According to the invention described in <6>, compared with the case where the adhesive resin in the charge-generating layer is a vinyl acetate homopolymer, an electrophotographic photosensitive material with superior ability to suppress localized deterioration of electrical properties after long-term printing is provided.

[0049] According to the invention described in <7>, compared to the case where the charge transport layer does not contain polycarbonate resin, an electrophotographic photosensitive material with superior ability to suppress localized deterioration of electrical properties after long-term printing is provided.

[0050] According to the invention described in <8> or <9>, compared to the case where the charge transport layer of an electrophotographic photoreceptor contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B), and the charge generation layer contains gallium chlorophthalocyanine as a charge generation material, and the content of the binder resin in the charge generation layer / the total content of the binder resin and the charge generation material is 0.4 or less or 0.7 or more, a processing cartridge or image forming apparatus with excellent suppression of local deterioration of electrical properties after long-term printing is provided. Attached Figure Description

[0051] The embodiments of the present invention will be described in detail with reference to the following figures.

[0052] Figure 1 This is a partial cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor according to this embodiment;

[0053] Figure 2 This is a schematic structural diagram illustrating an example of the image forming apparatus according to this embodiment;

[0054] Figure 3 This is a schematic structural diagram showing another example of the image forming apparatus according to this embodiment.

[0055] Symbol Explanation

[0056] 1-Conductive substrate, 2-Undercoat layer, 3-Charge generation layer, 4-Charge transport layer, 5-Photosensitive layer, 10A-Photoreceptor.

[0057] 7-Electrophotographic photosensitive element, 8-Electrified 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 scraper, 132-Fiber-like component (roller-like), 133-Fiber-like component (flat brush-like), 300-Processing box. Detailed Implementation

[0058] Hereinafter, a detailed description will be given as an example of an embodiment of the present invention.

[0059] In this specification, the numerical range represented by “~” indicates the range to be included by taking the values ​​before and after “~” as the minimum and maximum values, respectively.

[0060] In the numerical ranges described in this specification, the upper or lower limit of a numerical range can be replaced with the upper or lower limit of other numerical ranges described in different periods. Furthermore, within the numerical ranges described in this specification, the upper or lower limit of that range can be replaced with the values ​​shown in the embodiments.

[0061] In this specification, the term "process" includes not only individual processes, but also processes that achieve their purpose, even if they cannot be clearly distinguished from other processes.

[0062] In this specification, when embodiments are described with reference to the accompanying drawings, the structure of the embodiments is not limited to the structure shown in the drawings. Furthermore, the sizes of the components in the figures are conceptual, and the relative sizes of the components are not limited thereto.

[0063] In this specification, each component may contain multiple corresponding substances. In this embodiment, when referring to the amount of each component in the composition, if multiple substances corresponding to each component are present in the composition, it indicates the total amount of the multiple substances present in the composition unless otherwise specified.

[0064] This specification may include multiple particles corresponding to each component. When multiple particles corresponding to each component are present in the composition, unless otherwise specified, the particle size of each component represents a value with respect to the mixture of the multiple particles present in the composition.

[0065] Unless otherwise specified in this specification, alkyl and alkylene groups include straight-chain, branched, and cyclic forms.

[0066] In this specification, regarding organic groups, aromatic rings, linking groups, alkyl groups, alkylene groups, aryl groups, aralkyl groups, alkoxy groups, aryloxy groups, etc., the hydrogen atoms in these groups may be replaced by halogen atoms.

[0067] In this specification, when compounds are represented by structural formulas, sometimes the symbols (C and H) representing the hydrocarbon group and / or the carbon and hydrogen atoms in the hydrocarbon chain are omitted.

[0068] In this specification, the term "structural unit" for copolymers or resins has the same meaning as that for monomer units.

[0069] In this specification, ppm is short for parts per million, which is a quality standard.

[0070] <Electronic Photoreceptor>

[0071] The electrophotographic photosensitive material according to this embodiment comprises: a conductive substrate; and a stacked photosensitive layer disposed on the conductive substrate and having a charge generating layer and a charge transport layer, wherein the charge transport layer contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B), the charge generating layer contains gallium chlorophthalocyanine as a charge generating material, and the content of the binder resin in the charge generating layer / the total content of the binder resin and the charge generating material is greater than 0.4 and less than 0.7.

[0072] [Chemical Formula 5]

[0073]

[0074] In equation (A), Ar A1 and Ar A2 Each is an aromatic ring that can have substituents, L A It is a single bond or a divalent linker, nA1 It can be 0, 1, or 2.

[0075] In equation (B), Ar B1 and Ar B2 Each is an aromatic ring that can have substituents, L B It is a single bond, an oxygen atom, a sulfur atom, or -C(Rb) 1 (Rb) 2 )-,n B1 It can be 0, 1, or 2. Rb 1 and Rb 2 Rb is independently composed of hydrogen atoms, an alkyl group having 1 or more but less than 20 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an aralkyl group having 7 or more but less than 20 carbon atoms. 1 With Rb 2 They can bond together to form cyclic alkyl groups.

[0076] Polyaryl ester resins are synthesized using acid chlorides, so as impurities, the acid chlorides themselves or deactivated dicarboxylic acids are likely to remain.

[0077] If acid chlorides or dicarboxylic acids are present as impurities, they are presumed to interact with the charge-generating material, thereby causing localized deterioration of electrical properties. Furthermore, it is believed that even if there are no problems initially, the acid components will move to the vicinity of the charge-generating material and interact with it over time, which is also one of the reasons for the localized deterioration of electrical properties.

[0078] Hydroxy gallium phthalocyanine, as a charge-generating material, is thought to readily interact with acid components, leading to a deterioration in its electrical properties. On the other hand, gallium chlorophthalocyanine is considered to be less likely to interact with acid components, to remain stable over time, and to maintain stable electrical properties over the long term.

[0079] Furthermore, regarding polyarylate resins using phthalic acid, phthalic acid has a high acidity, and therefore it is presumed that it easily interacts with gallium chlorophthalocyanine, thus becoming a cause of deterioration in electrical properties.

[0080] Furthermore, it is presumed that when the ratio of the binder resin content to the total content of the binder resin and charge-generating material in the charge-generating layer is less than 0.4, the proportion of charge-generating material interacting with the acid component increases, thus leading to localized deterioration of electrical properties. It is believed that when the ratio of the binder resin content to the total content of the binder resin and charge-generating material is greater than 0.7, the proportion of charge-generating material interacting with the acid component decreases, but the impact of localized deterioration of electrical properties during interaction increases, thus leading to further deterioration of electrical properties.

[0081] In the electrophotographic photosensitive material of this embodiment, the charge transport layer contains a polyarylate resin having dicarboxylic acid units (A) and diol units (B), and the charge generation layer contains gallium chlorophthalocyanine. The ratio of the content of the binder resin in the charge generation layer to the total content of the binder resin and the charge generation material is greater than 0.4 and less than 0.7. As a result, the interaction between the charge generation material and the acid component is suppressed, thereby exhibiting excellent suppression of local deterioration of electrical properties after long-term printing.

[0082] The electrophotographic photoreceptor (hereinafter also referred to as "photoreceptor") according to this embodiment includes a conductive substrate and a stacked photosensitive layer disposed on the conductive substrate and having a charge generation layer and a charge transport layer.

[0083] The electrophotographic photosensitive material involved in this embodiment may also have other layers (e.g., a bottom layer, an intermediate layer).

[0084] Figure 1 This is a partial cross-sectional view that schematically illustrates an example of the layer structure of the photoreceptor involved in this embodiment. Figure 1 The photoreceptor 10A shown has a stacked photosensitive layer. The photoreceptor 10A has a structure in which a lower coating layer 2, a charge generation layer 3, and a charge transport layer 4 are sequentially stacked on a conductive substrate 1. The charge generation layer 3 and the charge transport layer 4 constitute the photosensitive layer 5 (a so-called functionally separated photosensitive layer). The photoreceptor 10A may have an intermediate layer (not shown) between the lower coating layer 2 and the charge generation layer 3. The lower coating layer 2 may or may not be present.

[0085] The following is a detailed description of each layer of the photoreceptor.

[0086] [charge transport layer]

[0087] The charge transport layer in the electrophotographic photosensitive body according to this embodiment contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B).

[0088] Polyaryl ester resins improve the wear resistance of the charge transport layer by stacking aromatic rings, which binds the resin molecules together through intermolecular forces. For example, condensation polymers of bisphenols and aromatic dicarboxylic acids are preferred polyaryl ester resins. Examples of polyaryl ester resin forms include polyaryl ester resins (PA) described later.

[0089] The polyaryl ester resin included in the charge transport layer contains at least a polyaryl ester resin having a dicarboxylic acid unit (A) and a diol unit (B). In this invention, the polyaryl ester resin is referred to as polyaryl ester resin (PA).

[0090] The dicarboxylic acid unit (A) is the structural unit represented by the following formula (A).

[0091] [Chemical Formula 6]

[0092]

[0093] In equation (A), Ar A1 and Ar A2 Each is an aromatic ring that can have substituents, L A It is a single bond or a divalent linker, n A1 It can be 0, 1, or 2.

[0094] Ar A1 The aromatic ring can be any of a monocyclic or polycyclic aromatic ring. Examples of aromatic rings include benzene rings, naphthalene rings, anthracene rings, and phenanthrene rings, with benzene rings and naphthalene rings being preferred.

[0095] Ar A1 The hydrogen atoms on the aromatic ring can be replaced by alkyl, aryl, aralkyl, alkoxy, aryloxy, halogen atoms, etc. As Ar... A1 When the aromatic ring is substituted, the substituents are preferably alkyl groups having 1 or more and 10 or less carbon atoms, aryl groups having 6 or more and 12 or less carbon atoms, and alkoxy groups having 1 or more and 6 or less carbon atoms.

[0096] Ar A2 The aromatic ring can be any of a monocyclic or polycyclic aromatic ring. Examples of aromatic rings include benzene rings, naphthalene rings, anthracene rings, and phenanthrene rings, with benzene rings and naphthalene rings being preferred.

[0097] Ar A2 The hydrogen atoms on the aromatic ring can be replaced by alkyl, aryl, aralkyl, alkoxy, aryloxy, halogen atoms, etc. As Ar... A2 When the aromatic ring is substituted, the substituents are preferably alkyl groups having 1 or more and 10 or less carbon atoms, aryl groups having 6 or more and 12 or less carbon atoms, and alkoxy groups having 1 or more and 6 or less carbon atoms.

[0098] When L A When the linking group is divalent, examples of divalent linking groups include oxygen atoms, sulfur atoms, and -C(Ra). 1 (Ra) 2 )-。 Here, Ra 1 and Ra 2 Ra is independently composed of hydrogen atoms, an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an aralkyl group having 7 or more but less than 20 carbon atoms. 1 With Ra 2 They can bond together to form cyclic alkyl groups.

[0099] Ra 1 and Ra2 The alkyl group involving 1 or more and 10 or less carbon atoms can be any of straight-chain, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 or more and 6 or less, more preferably 1 or more and 4 or less, and even more preferably 1 or 2.

[0100] Ra 1 and Ra 2 The aryl group involving 6 or more but less than 12 carbon atoms can be either monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 or more but less than 10, and more preferably 6.

[0101] Ra 1 and Ra 2 The alkyl group in the aralkyl group with 7 or more and 20 or less carbon atoms can be any one of straight-chain, branched, or cyclic. The number of carbon atoms in the alkyl group of the aralkyl group with 7 or more and 20 or less carbon atoms is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, and even more preferably 1 or 2.

[0102] Ra 1 and Ra 2 The aryl group in the aralkyl group involving 7 or more and 20 or less carbon atoms can be any of a monocyclic or polycyclic ring. The number of carbon atoms in the aryl group is preferably 6 or more and 10 or less, more preferably 6.

[0103] From the viewpoint of suppressing localized deterioration of electrical properties after long-term printing, the dicarboxylic acid unit (A) preferably comprises at least one selected from the group consisting of dicarboxylic acid units (A1) represented by formula (A1), dicarboxylic acid units (A2) represented by formula (A2), dicarboxylic acid units (A3) represented by formula (A3), dicarboxylic acid units (A4) represented by formula (A4), and dicarboxylic acid units (A5). The dicarboxylic acid unit (A) is more preferably composed of at least one selected from the group consisting of dicarboxylic acid units (A2), dicarboxylic acid units (A3), and dicarboxylic acid units (A4), and even more preferably comprises a dicarboxylic acid unit (A2).

[0104] [Chemical Formula 7]

[0105]

[0106] In equation (A1), n 101 n is an integer greater than or equal to 0 and less than or equal to 4. 101 Ra 101 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0107] n 101For example, 0, 1 or 2 is preferred, more preferably 0 or 1, and even more preferably 0.

[0108] [Chemical Formula 8]

[0109]

[0110] In equation (A2), n 201 and n 202 Each of the following is an independent integer greater than 0 and less than 4, n 201 Ra 201 and n 202 Ra 202 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0111] n 201 For example, 0, 1 or 2 is preferred, more preferably 0 or 1, and even more preferably 0.

[0112] n 202 For example, 0, 1 or 2 is preferred, more preferably 0 or 1, and even more preferably 0.

[0113] [Chemical Formula 9]

[0114]

[0115] In equation (A3), n 301 and n 302 Each of the following is an independent integer greater than 0 and less than 4, n 301 Ra 301 and n 302 Ra 302 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0116] n 301 For example, 0, 1 or 2 is preferred, more preferably 0 or 1, and even more preferably 0.

[0117] n 302 For example, 0, 1 or 2 is preferred, more preferably 0 or 1, and even more preferably 0.

[0118] [Chemical Formula 10]

[0119]

[0120] In equation (A4), n 401 n is an integer greater than 0 and less than 6. 401 Ra 401Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0121] n 401 For example, it is preferably an integer greater than or equal to 0 and less than or equal to 4, more preferably 0, 1 or 2, and even more preferably 0.

[0122] [Chemical Formula 11]

[0123]

[0124] In equation (A5), n 501 n 502 and n 503 Each of the following is an independent integer greater than 0 and less than 4, n 501 Ra 501 n 502 Ra 502 and n 503 Ra 503 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0125] n 501 For example, 0, 1 or 2 is preferred, more preferably 0 or 1, and even more preferably 0.

[0126] n 502 For example, 0, 1 or 2 is preferred, more preferably 0 or 1, and even more preferably 0.

[0127] n 503 For example, 0, 1 or 2 is preferred, more preferably 0 or 1, and even more preferably 0.

[0128] Ra of formula (A1) 101 Ra of formula (A2) 201 and Ra 202 Ra of formula (A3) 301 and Ra 302 Ra of formula (A4) 401 And Ra of formula (A5) 501 Ra 502 and Ra 503 The specific form and preferred form are the same, therefore Ra will be described below. 101 Ra 201 Ra 202 Ra 301 Ra 302 Ra 401 Ra 501 Ra 502 and Ra503 We will refer to them collectively as "Ra" for explanation.

[0129] The alkyl group involved in Ra with 1 or more and 10 or less carbon atoms can be any of straight-chain, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 or more and 6 or less, more preferably 1 or more and 4 or less, and even more preferably 1 or 2.

[0130] Examples of straight-chain alkyl groups with 1 or more but less than 10 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl.

[0131] Examples of branched alkyl groups with 3 or more but less than 10 carbon atoms include isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isohexyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodel, sec-decyl, and tert-decyl.

[0132] Examples of cyclic alkyl groups with 3 or more but less than 10 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and polycyclic (e.g., bicyclic, tricyclic, spirocyclic) alkyl groups formed by linking these monocyclic alkyl groups.

[0133] The aryl group involved in Ra, which has 6 or more but less than 12 carbon atoms, can be either monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 or more but less than 10, and more preferably 6.

[0134] Examples of aryl groups with 6 or more but less than 12 carbon atoms include phenyl, biphenyl, 1-naphthyl, and 2-naphthyl.

[0135] The alkyl group in the alkoxy group involving Ra, which has 1 or more and 6 or less carbon atoms, can be any of the straight-chain, branched, and cyclic forms. The alkyl group in the alkoxy group, which has 1 or more and 4 or less carbon atoms, is preferably 1 or more and 3 or less, and even more preferably 1 or 2.

[0136] Examples of straight-chain alkoxy groups with 1 or more but less than 6 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, and n-hexoxy.

[0137] Examples of branched alkoxy groups with 3 or more but less than 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentoxy, neopentoxy, tert-pentoxy, isohexoxy, sec-hexoxy, and tert-hexoxy.

[0138] Examples of cyclic alkoxy groups with 3 or more but less than 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentoxy, and cyclohexoxy.

[0139] Hereinafter, dicarboxylic acid units (A1-1) to (A1-9) are specifically shown as dicarboxylic acid units (A1). The dicarboxylic acid unit (A1) is not limited to this.

[0140] [Chemical Formula 12]

[0141]

[0142] The following examples of dicarboxylic acid units (A2-1) to (A2-3) are shown as specific examples of dicarboxylic acid units (A2). The dicarboxylic acid unit (A2) is not limited to these examples.

[0143] [Chemical Formula 13]

[0144]

[0145] Hereinafter, dicarboxylic acid units (A3-1) to (A3-2) are specifically shown as dicarboxylic acid units (A3). The dicarboxylic acid unit (A3) is not limited to these.

[0146] [Chemical Formula 14]

[0147]

[0148] Hereinafter, dicarboxylic acid units (A4-1) to (A4-3) are specifically shown as dicarboxylic acid units (A4). The dicarboxylic acid unit (A4) is not limited to these.

[0149] [Chemical Formula 15]

[0150]

[0151] Hereinafter, dicarboxylic acid units (A5-1) to (A5-4) are specifically shown as dicarboxylic acid units (A5). The dicarboxylic acid unit (A5) is not limited to these.

[0152] [Chemical Formula 16]

[0153]

[0154] As a dicarboxylic acid unit (A), it is preferred to include at least one selected from the group consisting of (A1-1), (A1-7), (A2-3), (A3-2) and (A4-3) of the above specific examples, more preferably to include at least one selected from the group consisting of (A2-3), (A3-2) and (A4-3), and even more preferably to include at least (A2-3).

[0155] The dicarboxylic acid unit (A) contained in polyaryl ester resin (PA) can be one or more.

[0156] The mass percentage of dicarboxylic acid unit (A) in polyarylate resin (PA) is preferably 15% by mass or more and 60% by mass or less.

[0157] If the mass percentage of dicarboxylic acid unit (A) is 15% by mass or more, the charge transport layer exhibits good wear resistance. From this perspective, the mass percentage of dicarboxylic acid unit (A) is more preferably 20% by mass or more, and even more preferably 25% by mass or more.

[0158] If the mass percentage of the dicarboxylic acid unit (A) is 60% by mass or less, the stripping of the charge transport layer can be suppressed. From this point of view, the mass percentage of the dicarboxylic acid unit (A) is more preferably 55% by mass or less, and even more preferably 50% by mass or less.

[0159] Polyaryl ester resins (PA) may contain dicarboxylic acid units other than the dicarboxylic acid unit (A). Examples of other dicarboxylic acid units include, for instance, aliphatic dicarboxylic acid units (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citracic acid, itaconic acid, pentenic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid), alicyclic dicarboxylic acid units (e.g., cyclohexanedicarboxylic acid), and their lower (e.g., having 1 or more but less than 5 carbon atoms) alkyl ester units. The polyaryl ester resin (PA) may contain one or more of these dicarboxylic acid units.

[0160] The diol unit (B) is the structural unit represented by the following formula (B).

[0161] [Chemical Formula 17]

[0162]

[0163] In equation (B), Ar B1 and Ar B2 Each is an aromatic ring that can have substituents, L B It is a single bond, an oxygen atom, a sulfur atom, or -C(Rb) 1 (Rb) 2 )-,n B1 It can be 0, 1, or 2. Rb 1 and Rb 2 Rb is independently composed of hydrogen atoms, an alkyl group having 1 or more but less than 20 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an aralkyl group having 7 or more but less than 20 carbon atoms. 1 With Rb 2 They can bond together to form cyclic alkyl groups.

[0164] Ar B1The aromatic ring can be any of a monocyclic or polycyclic aromatic ring. Examples of aromatic rings include benzene rings, naphthalene rings, anthracene rings, and phenanthrene rings, with benzene rings and naphthalene rings being preferred.

[0165] Ar B1 The hydrogen atoms on the aromatic ring can be replaced by alkyl, aryl, aralkyl, alkoxy, aryloxy, halogen atoms, etc. As Ar... B1 When the aromatic ring is substituted, the substituents are preferably alkyl groups having 1 or more and 10 or less carbon atoms, aryl groups having 6 or more and 12 or less carbon atoms, and alkoxy groups having 1 or more and 6 or less carbon atoms.

[0166] Ar B2 The aromatic ring can be any of a monocyclic or polycyclic aromatic ring. Examples of aromatic rings include benzene rings, naphthalene rings, anthracene rings, and phenanthrene rings, with benzene rings and naphthalene rings being preferred.

[0167] Ar B2 The hydrogen atoms on the aromatic ring can be replaced by alkyl, aryl, aralkyl, alkoxy, aryloxy, halogen atoms, etc. As Ar... B2 When the aromatic ring is substituted, the substituents are preferably alkyl groups having 1 or more and 10 or less carbon atoms, aryl groups having 6 or more and 12 or less carbon atoms, and alkoxy groups having 1 or more and 6 or less carbon atoms.

[0168] Rb 1 and Rb 2 The alkyl group involving 1 or more and 20 or less carbon atoms can be any of straight-chain, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 or more and 18 or less, more preferably 1 or more and 14 or less, and even more preferably 1 or more and 10 or less.

[0169] Rb 1 and Rb 2 The aryl group involving 6 or more but less than 12 carbon atoms can be either monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 or more but less than 10, and more preferably 6.

[0170] Rb 1 and Rb 2 The alkyl group in the aralkyl group with 7 or more and 20 or less carbon atoms can be any one of straight-chain, branched, or cyclic. The number of carbon atoms in the alkyl group of the aralkyl group with 7 or more and 20 or less carbon atoms is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, and even more preferably 1 or 2.

[0171] Rb 1 and Rb 2The aryl group in the aralkyl group involving 7 or more and 20 or less carbon atoms can be any of a monocyclic or polycyclic ring. The number of carbon atoms in the aryl group is preferably 6 or more and 10 or less, more preferably 6.

[0172] From the viewpoint of suppressing local deterioration of electrical properties after long-term printing, the diol unit (B) preferably comprises, for example, at least one selected from the group consisting of diol unit (B1) represented by formula (B1), diol unit (B2) represented by formula (B2), diol unit (B3) represented by formula (B3), diol unit (B4) represented by formula (B4), diol unit (B5) represented by formula (B5), diol unit (B6) represented by formula (B6), diol unit (B7) represented by formula (B7) and diol unit (B8) represented by formula (B8).

[0173] The diol unit (B) more preferably comprises at least one selected from the group consisting of diol units (B1) represented by formula (B1), diol units (B2) represented by formula (B2), diol units (B4) represented by formula (B4), diol units (B5) represented by formula (B5), and diol units (B6) represented by formula (B6).

[0174] Further preferably, it comprises at least one selected from the group consisting of diol units (B1) represented by formula (B1), diol units (B2) represented by formula (B2), diol units (B5) represented by formula (B5), and diol units (B6) represented by formula (B6).

[0175] More preferably, it comprises at least one selected from the group consisting of diol units (B1) represented by formula (B1), diol units (B2) represented by formula (B2), and diol units (B6) represented by formula (B6).

[0176] Most preferably, it comprises at least one of the groups consisting of diol units (B1) represented by formula (B1) and diol units (B2) represented by formula (B2).

[0177] [Chemical Formula 18]

[0178]

[0179] In equation (B1), Rb 101 Branched alkyl groups with 4 or more but less than 20 carbon atoms, Rb 201 Rb is an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms. 401 、Rb 501 、Rb 801 and Rb 901Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0180] Rb 101 The branched alkyl group involving 4 or more and 20 or less carbon atoms preferably has 4 or more and 16 or less carbon atoms, more preferably 4 or more and 12 or less, and even more preferably 4 or more and 8 or less. As Rb 101 Specific examples include isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isohexyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodel, sec-decyl, tert-decyl, isododecyl, sec-dodecyl, tert-dodecyl, tert-tetradecyl, tert-pentadecanyl, etc.

[0181] [Chemical Formula 19]

[0182]

[0183] In equation (B2), Rb 102 Rb is a straight-chain alkyl group with 4 or more but less than 20 carbon atoms. 202 Rb is an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms. 402 、Rb 502 、Rb 802 and Rb 902 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0184] Rb 102 The linear alkyl group involving 4 or more and 20 carbon atoms preferably has 4 or more and 16 or less carbon atoms, more preferably 4 or more and 12 or less, and even more preferably 4 or more and 8 or less. As Rb 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-pentadecanyl, n-heptadecyl, n-octadecyl, n-nonadecanyl, n-eicosyl, etc.

[0185] [Chemical Formula 20]

[0186]

[0187] In equation (B3), Rb 113 and Rb 213 Each of the following is independently a hydrogen atom, a straight-chain alkyl group having 1 or more but less than 3 carbon atoms, an alkoxy group having 1 or more but less than 4 carbon atoms, or a halogen atom, where d is an integer between 7 and 15, and Rb403 、Rb 503 、Rb 803 and Rb 903 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0188] Rb 113 and Rb 213 The number of carbon atoms in the straight-chain alkyl group involving 1 or more and 3 or less is preferably 1 or 2, more preferably 1. Specific examples of this group include methyl, ethyl, and n-propyl.

[0189] Rb 113 and Rb 213 The alkyl group in the alkoxy group with 1 or more and 4 or fewer carbon atoms can be any of the following: linear, branched, and cyclic. The alkyl group in the alkoxy group with 1 or more and 4 or fewer carbon atoms preferably has 1 or more and 3 or fewer carbon atoms, more preferably 1 or 2, and even more preferably 1. Specific examples of this group include methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclopropoxy, and cyclobutoxy.

[0190] As Rb 113 and Rb 213 The halogen atoms involved can be fluorine, chlorine, bromine, and iodine.

[0191] [Chemical Formula 21]

[0192]

[0193] In equation (B4), Rb 104 and Rb 204 Each is independently an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms, Rb 404 、Rb 504 、Rb 804 and Rb 904 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0194] Rb 104 The alkyl group involving 1 to 3 carbon atoms can be linear, branched, or cyclic. The alkyl group preferably has 1 or 2 carbon atoms, more preferably 1. As Rb 104 Specific examples include methyl, ethyl, n-propyl, isopropyl, and cyclopropyl.

[0195] [Chemical Formula 22]

[0196]

[0197] In equation (B5), Ar 105 Rb is an aryl group having 6 or more but less than 12 carbon atoms, or an aralkyl group having 7 or more but less than 20 carbon atoms. 205 Rb is an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms. 405 、Rb 505 、Rb 805 and Rb 905 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0198] Ar 105 The aryl group involving 6 or more but less than 12 carbon atoms can be either monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 or more but less than 10, and more preferably 6.

[0199] Ar 105 The alkyl group in the aralkyl group having 7 or more and 20 or fewer carbon atoms can be any of straight-chain, branched, or cyclic. The alkyl group in the aralkyl group having 7 or more and 20 or fewer carbon atoms preferably has 1 or more and 4 or fewer carbon atoms, more preferably 1 or more and 3 or fewer carbon atoms, and even more preferably 1 or 2 carbon atoms. 105 The aryl group in the aralkyl group with 7 or more and 20 or less carbon atoms can be either monocyclic or polycyclic. The number of carbon atoms in the aryl group is preferably 6 or more and 10 or less, more preferably 6. Examples of aralkyl groups with 7 or more and 20 or less carbon atoms include benzyl, phenylethyl, phenylpropyl, 4-phenylbutyl, phenylpentyl, phenylhexyl, phenylheptyl, phenyloctyl, phenylnonyl, naphthylmethyl, naphthylethyl, anthraceneylmethyl, and phenyl-cyclopentylmethyl.

[0200] [Chemical Formula 23]

[0201]

[0202] In equation (B6), Rb 116 and Rb 216 Each of the following is independently a hydrogen atom, a straight-chain alkyl group having 1 or more but less than 3 carbon atoms, an alkoxy group having 1 or more but less than 4 carbon atoms, or a halogen atom, where e is an integer of 4 or more but less than 6, and Rb 406 、Rb 506 、Rb 806 and Rb 906 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0203] Rb 116and Rb 216 The number of carbon atoms in the straight-chain alkyl group involving 1 or more and 3 or less is preferably 1 or 2, more preferably 1. Specific examples of this group include methyl, ethyl, and n-propyl.

[0204] Rb 116 and Rb 216 The alkyl group in the alkoxy group with 1 or more and 4 or fewer carbon atoms can be any of the following: linear, branched, and cyclic. The alkyl group in the alkoxy group with 1 or more and 4 or fewer carbon atoms preferably has 1 or more and 3 or fewer carbon atoms, more preferably 1 or 2, and even more preferably 1. Specific examples of this group include methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclopropoxy, and cyclobutoxy.

[0205] As Rb 116 and Rb 216 The halogen atoms involved can be fluorine, chlorine, bromine, and iodine.

[0206] [Chemical Formula 24]

[0207]

[0208] In equation (B7), Rb 407 、Rb 507 、Rb 807 and Rb 907 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0209] [Chemical Formula 25]

[0210]

[0211] In equation (B8), Rb 408 、Rb 508 、Rb 808 and Rb 908 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0212] Rb in equation (B1) 201 Rb in equation (B2) 202 Rb in equation (B4) 204 and Rb of formula (B5) 205 The specific form and preferred form are the same, therefore, Rb will be referred to below. 201 、Rb 202 、Rb 204 and Rb 205Collectively referred to as "Rb" 200 To explain.

[0213] Rb 200 The alkyl group involved, having 1 or more but less than 3 carbon atoms, can be any of the following: straight-chain, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 or 2, and more preferably 1.

[0214] Examples of alkyl groups with 1 or more but less than 3 carbon atoms include methyl, ethyl, n-propyl, isopropyl, and cyclopropyl.

[0215] Rb in equation (B1) 401 Rb in equation (B2) 402 Rb in equation (B3) 403 Rb in equation (B4) 404 Rb in equation (B5) 405 Rb in equation (B6) 406 Rb in equation (B7) 407 and Rb of formula (B8) 408 The specific form and preferred form are the same, therefore, Rb will be referred to below. 401 、Rb 402 、Rb 403 、Rb 404 、Rb 405 、Rb 406 、Rb 407 and Rb 408 Collectively referred to as "Rb" 400 To explain.

[0216] Rb 400 The alkyl group involving 1 or more and 4 or less carbon atoms can be any of the following: straight-chain, branched, and cyclic. The alkyl group preferably has 1 or more and 3 or less carbon atoms, more preferably 1 or 2, and even more preferably 1.

[0217] Examples of straight-chain alkyl groups with 1 or more but less than 4 carbon atoms include methyl, ethyl, n-propyl, and n-butyl.

[0218] Examples of branched alkyl groups with 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl, and tert-butyl.

[0219] Examples of cyclic alkyl groups with 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0220] Rb 400 The alkyl group in the alkoxy group with 1 or more and 6 or less carbon atoms can be any of the straight-chain, branched, and cyclic forms. The alkyl group in the alkoxy group with 1 or more and 6 or less carbon atoms preferably has 1 or more and 4 or less carbon atoms, more preferably 1 or more and 3 or less carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0221] Examples of straight-chain alkoxy groups with 1 or more but less than 6 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, and n-hexoxy.

[0222] Examples of branched alkoxy groups with 3 or more but less than 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentoxy, neopentoxy, tert-pentoxy, isohexoxy, sec-hexoxy, and tert-hexoxy.

[0223] Examples of cyclic alkoxy groups with 3 or more but less than 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentoxy, and cyclohexoxy.

[0224] As Rb 400 The halogen atoms involved can be fluorine, chlorine, bromine, and iodine.

[0225] Rb in equation (B1) 501 Rb in equation (B2) 502 Rb in equation (B3) 503 Rb in equation (B4) 504 Rb in equation (B5) 505 Rb in equation (B6) 506 Rb in equation (B7) 507 and Rb of formula (B8) 508 The specific form and preferred form are the same, therefore, Rb will be referred to below. 501 、Rb 502 、Rb 503 、Rb 504 、Rb 505 、Rb 506 、Rb 507 and Rb 508 Collectively referred to as "Rb" 500 To explain.

[0226] Rb 500 The alkyl group involving 1 or more and 4 or less carbon atoms can be any of the following: straight-chain, branched, and cyclic. The alkyl group preferably has 1 or more and 3 or less carbon atoms, more preferably 1 or 2, and even more preferably 1.

[0227] Examples of straight-chain alkyl groups with 1 or more but less than 4 carbon atoms include methyl, ethyl, n-propyl, and n-butyl.

[0228] Examples of branched alkyl groups with 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl, and tert-butyl.

[0229] Examples of cyclic alkyl groups with 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0230] Rb 500 The alkyl group in the alkoxy group with 1 or more and 6 or less carbon atoms can be any of the straight-chain, branched, and cyclic forms. The alkyl group in the alkoxy group with 1 or more and 6 or less carbon atoms preferably has 1 or more and 4 or less carbon atoms, more preferably 1 or more and 3 or less carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0231] Examples of straight-chain alkoxy groups with 1 or more but less than 6 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, and n-hexoxy.

[0232] Examples of branched alkoxy groups with 3 or more but less than 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentoxy, neopentoxy, tert-pentoxy, isohexoxy, sec-hexoxy, and tert-hexoxy.

[0233] Examples of cyclic alkoxy groups with 3 or more but less than 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentoxy, and cyclohexoxy.

[0234] As Rb 500 The halogen atoms involved can be fluorine, chlorine, bromine, and iodine.

[0235] Rb in equation (B1) 801 Rb in equation (B2) 802 Rb in equation (B3) 803 Rb in equation (B4) 804 Rb in equation (B5) 805 Rb in equation (B6) 806 Rb in equation (B7) 807 and Rb of formula (B8) 808 The specific form and preferred form are the same, therefore, Rb will be referred to below. 801 、Rb 802 、Rb 803 、Rb 804 、Rb 805 、Rb 806 、Rb 807 and Rb 808 Collectively referred to as "Rb" 800 To explain.

[0236] Rb 800 The alkyl group involving 1 or more and 4 or less carbon atoms can be any of the following: straight-chain, branched, and cyclic. The alkyl group preferably has 1 or more and 3 or less carbon atoms, more preferably 1 or 2, and even more preferably 1.

[0237] Examples of straight-chain alkyl groups with 1 or more but less than 4 carbon atoms include methyl, ethyl, n-propyl, and n-butyl.

[0238] Examples of branched alkyl groups with 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl, and tert-butyl.

[0239] Examples of cyclic alkyl groups with 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0240] Rb 800 The alkyl group in the alkoxy group with 1 or more and 6 or less carbon atoms can be any of the straight-chain, branched, and cyclic forms. The alkyl group in the alkoxy group with 1 or more and 6 or less carbon atoms preferably has 1 or more and 4 or less carbon atoms, more preferably 1 or more and 3 or less carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0241] Examples of straight-chain alkoxy groups with 1 or more but less than 6 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, and n-hexoxy.

[0242] Examples of branched alkoxy groups with 3 or more but less than 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentoxy, neopentoxy, tert-pentoxy, isohexoxy, sec-hexoxy, and tert-hexoxy.

[0243] Examples of cyclic alkoxy groups with 3 or more but less than 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentoxy, and cyclohexoxy.

[0244] As Rb 800 The halogen atoms involved can be fluorine, chlorine, bromine, and iodine.

[0245] Rb in equation (B1) 901 Rb in equation (B2) 902 Rb in equation (B3) 903 Rb in equation (B4) 904 Rb in equation (B5) 905 Rb in equation (B6) 906 Rb in equation (B7) 907 and Rb of formula (B8) 908 The specific form and preferred form are the same, therefore, Rb will be referred to below. 901 、Rb 902 、Rb 903 、Rb 904 、Rb 905 、Rb 906 、Rb 907 and Rb 908 Collectively referred to as "Rb" 900 To explain.

[0246] Rb 900The alkyl group involving 1 or more and 4 or less carbon atoms can be any of the following: straight-chain, branched, and cyclic. The alkyl group preferably has 1 or more and 3 or less carbon atoms, more preferably 1 or 2, and even more preferably 1.

[0247] Examples of straight-chain alkyl groups with 1 or more but less than 4 carbon atoms include methyl, ethyl, n-propyl, and n-butyl.

[0248] Examples of branched alkyl groups with 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl, and tert-butyl.

[0249] Examples of cyclic alkyl groups with 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0250] Rb 900 The alkyl group in the alkoxy group with 1 or more and 6 or less carbon atoms can be any of the straight-chain, branched, and cyclic forms. The alkyl group in the alkoxy group with 1 or more and 6 or less carbon atoms preferably has 1 or more and 4 or less carbon atoms, more preferably 1 or more and 3 or less carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0251] Examples of straight-chain alkoxy groups with 1 or more but less than 6 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, and n-hexoxy.

[0252] Examples of branched alkoxy groups with 3 or more but less than 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentoxy, neopentoxy, tert-pentoxy, isohexoxy, sec-hexoxy, and tert-hexoxy.

[0253] Examples of cyclic alkoxy groups with 3 or more but less than 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentoxy, and cyclohexoxy.

[0254] As Rb 900 The halogen atoms involved can be fluorine, chlorine, bromine, and iodine.

[0255] Hereinafter, diol units (B1-1) to (B1-6) are specifically shown as diol units (B1). The diol unit (B1) is not limited to this.

[0256] [Chemical Formula 26]

[0257]

[0258] Hereinafter, diol units (B2-1) to (B2-11) are specifically shown as diol units (B2). The diol unit (B2) is not limited to these.

[0259] [Chemical Formula 27]

[0260]

[0261] Hereinafter, diol units (B3-1) to (B3-4) are specifically shown as diol units (B3). The diol unit (B3) is not limited to these.

[0262] [Chemical Formula 28]

[0263]

[0264] Hereinafter, diol units (B4-1) to (B4-7) are specifically shown as diol units (B4). The diol unit (B4) is not limited to this.

[0265] [Chemical Formula 29]

[0266]

[0267] Hereinafter, diol units (B5-1) to (B5-6) are specifically shown as diol units (B5). The diol unit (B5) is not limited to these.

[0268] [Chemical Formula 30]

[0269]

[0270] Hereinafter, diol units (B6-1) to (B6-4) are specifically shown as diol units (B6). The diol unit (B6) is not limited to these.

[0271] [Chemical Formula 31]

[0272]

[0273] Hereinafter, diol units (B7-1) to (B7-3) are specifically shown as diol units (B7). The diol unit (B7) is not limited to these.

[0274] [Chemical Formula 32]

[0275]

[0276] Hereinafter, diol units (B8-1) to (B8-3) are specifically shown as diol units (B8). The diol unit (B8) is not limited to these.

[0277] [Chemical Formula 33]

[0278]

[0279] The diol unit (B) contained in polyaryl ester resin (PA) can be one or more.

[0280] The mass percentage of the diol unit (B) in the polyaryl ester resin (PA) is preferably 25% by mass or more and 80% by mass or less.

[0281] If the mass percentage of the diol unit (B) is 25% by mass or more, the stripping of the charge transport layer can be suppressed. From this point of view, the mass percentage of the diol unit (B) is more preferably 30% by mass or more, and even more preferably 35% by mass or more.

[0282] If the mass percentage of the diol unit (B) is 80% by mass or less, the wear resistance can be improved by maintaining the solubility relative to the coating liquid used to form the charge transport layer. From this point of view, the mass percentage of the diol unit (B) is more preferably 75% by mass or less, and even more preferably 70% by mass or less.

[0283] Polyaryl ester resins (PA) may contain diol units other than the diol unit (B). Examples of other diol units include, for instance, aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol) and alicyclic diols (e.g., cyclohexanediol, cyclohexanediol, hydrogenated bisphenol A). The polyaryl ester resin (PA) may contain one or more of these diol units.

[0284] The ends of polyarylate resins (PA) can be sealed or modified by end-capping agents or molecular weight regulators used during manufacturing. Examples of end-capping agents or molecular weight regulators include monohydric phenols, monohydric acyl chlorides, monohydric alcohols, and monohydric carboxylic acids.

[0285] Examples of monohydric phenols 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, and 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.

[0286] Examples of monoacyl chlorides include benzoyl chloride, benzoyl chloride, methanesulfonyl chloride, phenyl chloroformate, acetyl chloride, butyryl chloride, octanoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, phenylphosphonic chloride, and their substituted derivatives, which are all functional acid acyl halides.

[0287] Examples of monohydric alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, pentanol, hexanol, dodecyl alcohol, stearyl alcohol, benzyl alcohol, and phenylethanol.

[0288] Examples of monocarboxylic acids include acetic acid, propionic acid, octanoic acid, cyclohexanecarboxylic acid, benzoic acid, methylbenzoic acid, phenylacetic acid, p-tert-butylbenzoic acid, and p-methoxyphenylacetic acid.

[0289] The weight-average molecular weight of the polyaryl ester resin (PA) is preferably 30,000 or more and 300,000 or less, more preferably 40,000 or more and 250,000 or less, and even more preferably 50,000 or more and 200,000 or less.

[0290] The molecular weight of polyaryl ester resin (PA) is the molecular weight converted from polystyrene as determined by GPC (gel permeation chromatography). Tetrahydrofuran is used as the eluent in GPC.

[0291] Polyaryl ester resins (PA) are obtained by conventional methods involving the polycondensation of monomers containing dicarboxylic acid units (A), monomers containing diol units (B), and other monomers as needed. Examples of monomer polycondensation methods include interfacial polymerization, solution polymerization, and melt polymerization. Interfacial polymerization is a polymerization method that obtains polyesters by mixing a dicarboxyl halogen dissolved in a water-incompatible organic solvent and a diol dissolved in an alkaline aqueous solution. References related to interfacial polymerization include WMEARECKSON, J. Poly. Sci., XL399, 1959, Japanese Patent Publication No. 40-1959. Compared to solution polymerization, interfacial polymerization has a faster reaction rate, thus suppressing the hydrolysis of the dicarboxyl halogen, resulting in the production of high molecular weight polyaryl ester resins (PA).

[0292] Other resins included in the charge transport layer include, in addition to those mentioned above, polyarylate resins, polycarbonate resins, polyester resins other than polyarylate resins, 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-vinylcarbazole, polysilanes, etc. Two or more resins from these sources can be used in any combination.

[0293] From the viewpoint of the wear resistance of the charge transport layer and the suppression of localized deterioration of the electrical properties after long-term printing, it is preferable, for example, to include at least one of polyaryl ester resin and polycarbonate resin, and more preferably, to include both polyaryl ester resin and polycarbonate resin. For example, the morphology of the polyaryl ester resin and polycarbonate resin is also preferred from the viewpoint of forming a fine phase-separated structure in the charge transport layer.

[0294] From the viewpoint of forming a fine phase separation structure in the charge transport layer, the proportion of polyarylene resin in the total amount of polyarylene resin and polycarbonate resin contained in the charge transport layer is preferably 20% by mass or more and 80% by mass or less, more preferably 25% by mass or more and 75% by mass or less, and even more preferably 30% by mass or more and 70% by mass or less.

[0295] As a polycarbonate resin, a polycarbonate resin having a continuous structure of aromatic rings is preferred, for example. This polycarbonate resin, through the stacking of aromatic rings, allows resin molecules to be bonded together by intermolecular forces, thereby improving the wear resistance of the charge transport layer. For example, as a preferred form of polycarbonate resin, specifically, the polycarbonate resin disclosed in Japanese Patent Application Publication No. 2023-121553 can be cited. For example, as a more preferred form of polycarbonate resin, the polycarbonate resin used in the embodiments described later can be cited.

[0296] As a combination of polyarylate resin and polycarbonate resin, it is preferred, for example, to be a combination of resins that both have structural units containing biphenyl as represented by the following formula (BP).

[0297] [Chemical Formula 34]

[0298]

[0299] In equation (BP), j is an integer greater than 0 and less than 4, and j are R... 1 Each is independently methyl or ethyl, k is an integer greater than or equal to 0 and less than or equal to 4, and k R's are independent of each other. 2 Each can be methyl or ethyl, independently.

[0300] The biphenyl represented by formula (BP) can be the entire structure obtained by removing ester bonds (-C(=O)O-) or carbonate bonds (-OC(=O)O-) from the structural unit containing the biphenyl represented by formula (BP), or it can be a part of the structure. In other words, the right and left ends of the biphenyl represented by formula (BP) can be directly bonded to ester bonds or carbonate bonds independently, or they can be bonded to ester bonds or carbonate bonds through other atoms or groups.

[0301] j is an integer greater than or equal to 0 and less than 4, preferably an integer greater than or equal to 0 and less than 3, more preferably an integer greater than or equal to 0 and less than 2, further preferably 0 or 1, and especially preferably 0.

[0302] When j is an integer greater than or equal to 1, j R 1 Each is independently methyl or ethyl, for example preferably methyl.

[0303] k is an integer greater than or equal to 0 and less than 4, preferably an integer greater than or equal to 0 and less than 3, more preferably an integer greater than or equal to 0 and less than 2, further preferably 0 or 1, and especially preferably 0.

[0304] When k is an integer greater than or equal to 1, k R 2 Each is independently methyl or ethyl, for example preferably methyl.

[0305] The biphenyl represented by formula (BP) is preferably linked at a 4,4'-biphenyl position in the main chain.

[0306] As a combination of polyaryl ester resin and polycarbonate resin, a combination of polyaryl ester resin having at least one of dicarboxylic acid unit (A2-3) and diol unit (B7-1) and polycarbonate resin having structural unit (Cb7-1) is particularly preferred.

[0307] [Chemical Formula 35]

[0308]

[0309] The charge transport layer preferably also contains phenolic compounds.

[0310] Examples of phenolic compounds included in the charge transport layer include phenol, cresol, catechol, resorcinol, hydroquinone, naphthol, and bisphenols (bisphenol A, AP, AF, B, BP, C, C2, E, F, G, M, S, P, PH, TMC, Z). A single phenolic compound can be used, or two or more can be used simultaneously.

[0311] Hindered phenolic compounds can also be cited as examples of phenolic compounds.

[0312] From the viewpoint of suppressing the oxidative degradation of the charge transport layer, phenolic compounds, for example, preferably include hindered phenolic compounds. Generally, hindered phenolic compounds are compounds in which at least one of the ortho positions of the hydroxyl groups of phenol is substituted with a bulky group, and are known to exert an antioxidant effect on the composition.

[0313] Examples of hindered phenolic compounds include the following compounds.

[0314] Alkylated monophenol compounds and their derivatives: for example, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, octyl-3,5-di-tert-butyl-4-hydroxy-hydroxycinnamate.

[0315] Alkylated hydroquinone compounds and their derivatives: for example, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-pentylhydroquinone

[0316] Alkyl thiocresol compounds and their derivatives: for example, 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,4-dioctylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-docodecylthiomethyl-4-nonylphenol

[0317] Alkylene bisphenol compounds and their derivatives: for example, 4,4'-butyride bis(6-tert-butyl-3-methylphenol), 2,2'-methylene bis(6-tert-butyl-4-methylphenol), 2,2'-methylene bis(6-tert-butyl-4-ethylphenol), 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane

[0318] Commercially available hindered phenolic compounds include ADEKA CORPORATION's "ADEKA STAB AO-80", "ADEKA STAB AO-60", "ADEKA STAB AO-50", "ADEKA STAB AO-40", "ADEKA STAB AO-30", "ADEKA STAB AO-20", and "ADEKA STAB AO-330"; BASF Japan Ltd.'s "Irganox 1010", "Irganox 245", "Irganox 1076", and "Irganox 1520"; and Sumitomo Chemical Co., Ltd.'s "Sumilizer GA-80", "Sumilizer GM", and "Sumilizer GS".

[0319] Hindered phenolic compounds can be used alone or in combination with two or more compounds.

[0320] From the viewpoint of promoting phase separation of two or more resins during the formation of the charge transport layer and forming a fine phase separation structure in the charge transport layer, the content of phenolic compounds contained in the charge transport layer is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 10% by mass or less, and even more preferably 1% by mass or more and 5% by mass or less, relative to the total mass of the charge transport layer.

[0321] In the charge transport layer, the proportion of fluoropolymer particles in the layer is preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0% by mass (i.e., it does not contain fluoropolymer particles).

[0322] Given the high likelihood of stricter restrictions on the manufacture and use of organofluorine compounds in the future, the content of fluoropolymer particles is preferably within the range described above.

[0323] The charge transport layer preferably contains a charge transport material.

[0324] Examples of charge transport materials include quinone compounds such as p-benzoquinone, chloroquinone, tetrabromobenzoquinone, and anthraquinone; dimethyl compounds such as tetracyano-p-benzodiquinone; fluorenone compounds such as 2,4,7-trinitrofluorenone; anthrone compounds; benzophenone compounds; cyanoethylene compounds; and ethylene compounds, all of which are electron transport compounds. Examples of hole transport materials include triarylamine compounds, benzidine compounds, arylalkyl compounds, aryl-substituted ethylene compounds, piracene compounds, anthracene compounds, and hydrazone compounds, all of which are hole transport compounds. These charge transport materials can be used alone or in combination, but are not limited to this.

[0325] The charge transport layer can be a layer containing a polymeric charge transport material.

[0326] Examples of polymeric charge transport materials include well-known chemical substances with charge transport properties such as poly-N-vinylcarbazole and polysilanes. Polyester-based polymeric charge transport materials are preferred, for example. These materials can be used alone or in combination with binder resins.

[0327] Examples of charge transport materials or polymeric charge transport materials include 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, organopolysilane 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, examples include paragraphs 0078-0080 of Japanese Patent Application Publication No. 2021-117377, paragraphs 0046-0048 of Japanese Patent Application Publication No. 2019-035900, paragraphs 0052-0053 of Japanese Patent Application Publication No. 2019-012141, paragraphs 0122-0134 of Japanese Patent Application Publication No. 2021-071565, and paragraphs 0021-0 The compounds described in paragraphs 0101 to 0110 of Japanese Patent Application Publication No. 15223, paragraph 0116 of Japanese Patent Application Publication No. 2013-097300, paragraphs 0309 to 0316 of International Publication No. 2019 / 070003, paragraphs 0103 to 0107 of Japanese Patent Application Publication No. 2018-159087, and paragraphs 0102 to 0113 of Japanese Patent Application Publication No. 2021-148818.

[0328] From the viewpoint of charge mobility, the charge transport material preferably comprises at least one selected from the group consisting of a chemical substance (C1) represented by formula (C1), a chemical substance (C2) represented by formula (C2), a chemical substance (C3) represented by formula (C3), and a chemical substance (C4) represented by formula (C4).

[0329] [Chemical Formula 36]

[0330]

[0331] In equation (C1), Ar T1 Ar T2 and Ar T3 They are independently aryl and -C6H4-C(R) T4 )=C(R T5 (R) T6 ) or -C6H4-CH=CH-CH=C(R T7 (R) T8 R T4 R T5 R T6 R T7 and R T8Each is independently a hydrogen atom, alkyl group, or aryl group. When R... T5 and R T6 When it is aryl, the aryl groups can cross each other via -C(R) 51 (R) 52 - and / or -C(R) 61 )=C(R 62 The divalent group of )- is linked. R 51 R 52 R 61 and R 62 Each is independently an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms.

[0332] The groups in formula (C1) may be substituted by halogen atoms, alkyl groups having 1 or more but less than 5 carbon atoms, alkoxy groups having 1 or more but less than 5 carbon atoms, or substituted amino groups having 1 or more but less than 3 carbon atoms.

[0333] As a chemical substance (C1), from the viewpoint of charge mobility, it is preferred, for example, to have at least one aryl group or -C6H4-CH=CH-CH=C(R T7 (R) T8 The chemical substance is more preferably the chemical substance represented by the following formula (C'1).

[0334] [Chemical Formula 37]

[0335]

[0336] In equation (C'1), R T111 R T112 R T121 R T122 R T131 and R T132 Each of the following is independently a hydrogen atom, a halogen atom, an alkyl group (preferably an alkyl group having 1 or more and 3 or less carbon atoms), an alkoxy group (preferably an alkoxy group having 1 or more and 3 or less carbon atoms), a phenyl group, or a phenoxy group. Tj1, Tj2, Tj3, Tk1, Tk2, and Tk3 are independently 0, 1, or 2.

[0337] [Chemical Formula 38]

[0338]

[0339] In equation (C2), R T201 R T202 R T211 and R T212 Each of the following is independently a halogen atom, an alkyl group having 1 or more but less than 5 carbon atoms, an alkoxy group having 1 or more but less than 5 carbon atoms, an amino group substituted with an alkyl group having 1 or 2 carbon atoms, an aryl group, or a -C(R) group.T21 )=C(R T22 (R) T23 ) or -CH=CH-CH=C(R T24 (R) T25 R T21 R T22 R T23 R T24 and R T25 Each can be independently a hydrogen atom, alkyl group, or aryl group. R T221 and R T222 Each of the following is independently a hydrogen atom, a halogen atom, an alkyl group having 1 or more but less than 5 carbon atoms, or an alkoxy group having 1 or more but less than 5 carbon atoms. Tm1, Tm2, ​​Tn1, and Tn2 are independently 0, 1, or 2, respectively.

[0340] The groups in formula (C2) may be substituted by halogen atoms, alkyl groups having 1 or more but less than 5 carbon atoms, alkoxy groups having 1 or more but less than 5 carbon atoms, or substituted amino groups having 1 or more but less than 3 carbon atoms.

[0341] As a chemical substance (C2), from the viewpoint of charge mobility, it is preferred, for example, to have at least one alkyl, aryl, or -CH=CH-CH=C(R) group. T24 (R) T25 The chemical substance, more preferably having at least two alkyl, aryl, or -CH=CH-CH=C(R) groups, is preferred. T24 (R) T25 ) chemical substances.

[0342] [Chemical Formula 39]

[0343]

[0344] In equation (C3), R T301 R T302 R T311 and R T312 Each of the following is independently a halogen atom, an alkyl group having 1 or more but less than 5 carbon atoms, an alkoxy group having 1 or more but less than 5 carbon atoms, an amino group substituted with an alkyl group having 1 or 2 carbon atoms, an aryl group, or a -C(R) group. T31 )=C(R T32 (R) T33 ) or -CH=CH-CH=C(R T34 (R) T35 R T31 R T32 R T33 R T34 and R T35 Each can be independently a hydrogen atom, alkyl group, or aryl group. R T321 R T322and R T331 Each of the following is independently a hydrogen atom, a halogen atom, an alkyl group having 1 or more but less than 5 carbon atoms, or an alkoxy group having 1 or more but less than 5 carbon atoms. To1, To2, Tp1, Tp2, Tq1, Tq2, and Tr1 are independently 0, 1, or 2, respectively.

[0345] The groups in formula (C3) may be substituted by halogen atoms, alkyl groups having 1 or more but less than 5 carbon atoms, alkoxy groups having 1 or more but less than 5 carbon atoms, or substituted amino groups having 1 or more but less than 3 carbon atoms.

[0346] [Chemical Formula 40]

[0347]

[0348] In equation (C4), R T401 R T402 R T411 and R T412 Each of the following is independently a halogen atom, an alkyl group having 1 or more but less than 5 carbon atoms, an alkoxy group having 1 or more but less than 5 carbon atoms, an amino group substituted with an alkyl group having 1 or 2 carbon atoms, an aryl group, or a -C(R) group. T41 )=C(R T42 (R) T43 ) or -CH=CH-CH=C(R T44 (R) T45 R T41 R T42 R T43 R T44 and R T45 Each can be independently a hydrogen atom, alkyl group, or aryl group. R T421 R T422 and R T431 Each of the following is independently a hydrogen atom, a halogen atom, an alkyl group having 1 or more but less than 5 carbon atoms, or an alkoxy group having 1 or more but less than 5 carbon atoms. Ts1, Ts2, Tt1, Tt2, Tu1, Tu2, and Tv1 are independently 0, 1, or 2, respectively.

[0349] The groups in formula (C4) may be substituted by halogen atoms, alkyl groups having 1 or more but less than 5 carbon atoms, alkoxy groups having 1 or more but less than 5 carbon atoms, or substituted amino groups having 1 or more but less than 3 carbon atoms.

[0350] The content of charge transport material contained in the charge transport layer relative to the total mass of the charge transport layer is preferably 20% by mass or more and 70% by mass or less.

[0351] Other known additives may be included in the charge transport layer.

[0352] There are no particular limitations on the formation of the charge transport layer, and known formation methods can be used. For example, a coating film can be formed by adding the above-mentioned components to a solvent for forming a charge transport layer, and the coating film can be dried and heated as needed.

[0353] Examples of solvents used in preparing coating solutions for charge transport layer formation include aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; ketones such as acetone and 2-butanone; halogenated aliphatic hydrocarbons such as dichloromethane, chloroform, and vinyl chloride; and cyclic or linear ethers such as tetrahydrofuran and diethyl ether. These solvents can be used alone or in combination of two or more.

[0354] Common methods for applying a coating liquid for forming a charge transport layer onto a charge generation layer include scraper coating, wire rod coating, spraying, dip coating, bead coating, air knife coating, and curtain coating.

[0355] The thickness of the charge transport layer can be set according to the function of the layer.

[0356] The thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 45 μm or less, and even more preferably 10 μm or more and 40 μm or less.

[0357] [charge generation layer]

[0358] The charge generation layer is, for example, a layer comprising a charge generation material and a binding resin. Furthermore, the charge generation layer can be a vapor-deposited layer of the charge generation material. Vapor-deposited layers of charge generation material are suitable, for example, for use with incoherent light sources such as LED (Light Emitting Diode) and organic EL (Electro-Luminescence) image arrays.

[0359] The ratio of the content of the adhesive resin in the charge-generating layer to the total content of the adhesive resin and the charge-generating material is greater than 0.4 and less than 0.7. From the viewpoint of suppressing the local deterioration of electrical properties after long-term printing, it is preferably 0.41 or more and 0.65 or less, more preferably greater than 0.43 and less than 0.60, and especially preferably greater than 0.43 and less than 0.50.

[0360] It contains gallium chlorophthalocyanine as a charge-generating material.

[0361] Other known charge-generating materials can be used in conjunction, but it is preferable not to use them, for example, from the viewpoint of suppressing localized deterioration of electrical properties after long-term printing.

[0362] The adhesive resin used in the charge generation layer is selected from a wide range of insulating resins, and the adhesive resin can be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinyl anthracene, polyvinylpyrene, and polysilane.

[0363] Examples of adhesive resins include polyvinyl butyral resin, polyarylate resins (condensates of bisphenols and aromatic dicarboxylic acids, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin, polyacrylamide resin, polyvinylpyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, and polyvinylpyrrolidone resin. Here, "insulation" refers to a volume resistivity of 1×10⁻⁶. 13 Ω·cm or higher.

[0364] Among them, from the viewpoint of suppressing the local deterioration of electrical properties after long-term printing, the adhesive resin is preferably a vinyl acetate-based resin or a polyvinyl butyral-based resin, more preferably a vinyl chloride-vinyl acetate copolymer or a polyvinyl butyral resin, and especially preferably a vinyl chloride-vinyl acetate copolymer.

[0365] These adhesive resins can be used alone or in combination of two or more.

[0366] Other known additives may be included in the charge generation layer.

[0367] There are no particular limitations on the formation of the charge-generating layer, and known formation methods can be used. However, for example, it can be performed by forming a coating film of a charge-generating layer forming liquid by adding the above-mentioned components to a solvent, drying the coating film, and heating it as needed. The formation of the charge-generating layer can be performed by vapor deposition of a charge-generating material. The formation of the charge-generating layer based on vapor deposition is particularly suitable, for example, when using polycyclic aromatic pigments or perylene pigments as charge-generating materials.

[0368] Examples of solvents used in preparing coating solutions for forming charge-generating layers 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, and toluene. These solvents can be used alone or in combination of two or more.

[0369] As a method for dispersing particles (e.g., charge-generating materials) in a coating liquid for forming a charge-generating layer, media dispersers such as ball mills, vibratory ball mills, grinders, sand mills, and horizontal sand mills, or media-free dispersers such as mixers, ultrasonic dispersers, roller mills, and high-pressure homogenizers can be used. Examples of high-pressure homogenizers include collision methods that disperse the dispersion by liquid-liquid collisions or liquid-wall collisions under high pressure, and penetration methods that disperse the dispersion by penetrating fine flow paths under high pressure. During dispersion, it is effective to set the average particle size of the charge-generating material in the coating liquid for forming the charge-generating layer to 0.5 μm or less, preferably 0.3 μm or less, and more preferably 0.15 μm or less.

[0370] Methods for applying a coating liquid for forming a charge generation layer onto an underlying layer (or an intermediate layer) include, for example, scraper coating, wire rod coating, spraying, dip coating, bead coating, air knife coating, curtain coating, and other common methods.

[0371] The thickness of the charge generation layer is preferably set in the range of 0.1 μm or more and 5.0 μm or less, and more preferably in the range of 0.2 μm or more and 2.0 μm or less.

[0372] [Conductive substrate]

[0373] Examples of conductive substrates include metal plates, metal drums, and metal strips containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.). Furthermore, examples of conductive substrates include conductive compounds (e.g., conductive polymers, indium oxide, etc.); paper coated, vapor-deposited, or laminated with metals (e.g., aluminum, palladium, gold, etc.) or alloys; resin films; and tapes. Here, "conductivity" refers to a volume resistivity of less than 1 × 10⁻⁶. 13 Ω·cm.

[0374] When an electrophotographic photosensitive material 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, based on the centerline average roughness Ra, in order to suppress interference fringes generated when the laser beam is irradiated. When incoherent light is used as the light source, roughening to prevent interference fringes is not particularly necessary, but suppressing the generation of defects caused by unevenness on the conductive substrate surface is beneficial for extending the lifespan.

[0375] Examples of roughening methods include wet grinding, which involves suspending an abrasive in water and spraying it onto a conductive substrate; centerless grinding, which involves pressing a conductive substrate onto a rotating grinding wheel and continuously grinding it; and anodizing.

[0376] As a roughening method, another example is a method in which conductive or semi-conductive powder is dispersed in a resin to form a layer on the surface of the conductive substrate without roughening the surface of the conductive substrate, and roughening is achieved by the particles dispersed in the layer.

[0377] Anodizing-based roughening processes involve anolysing a conductive metallic substrate (e.g., aluminum) in an electrolyte solution, thereby forming an oxide film on the surface of the conductive substrate. Examples of electrolyte solutions include sulfuric acid and oxalic acid. However, the porous anodic oxide film formed by anodizing is chemically active in its original state, easily contaminated, and exhibits significant resistance variations due to environmental factors. Therefore, it is preferable, for example, to perform a sealing treatment on the porous anodic oxide film, blocking the micropores of the oxide film by volume expansion caused by water and reaction in pressurized steam or boiling water (with the addition of metal salts such as nickel), thereby transforming it into a more stable hydrated oxide.

[0378] The thickness of the anodic oxide film is preferably 0.3 μm or more and 15 μm or less. If the film thickness is within the above range, there is a tendency for it to act as a barrier against implantation, and there is a tendency for the rise in residual potential caused by repeated use to be suppressed.

[0379] Conductive substrates can be treated with acidic solutions or boehmite.

[0380] The treatment based on the acidic treatment solution is carried out, for example, as follows. First, an acidic treatment solution containing phosphoric acid, chromic acid, and hydrofluoric acid is prepared. The proportions of phosphoric acid, chromic acid, and hydrofluoric acid in the acidic treatment solution are, for example, phosphoric acid in the range of 10% by mass or more and 11% by mass or less, chromic acid in the range of 3% by mass or more and 5% by mass or less, and hydrofluoric acid in the range of 0.5% by mass or more and 2% by mass or less. The concentration of their total acid content is preferably in the range of 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably, for example, 42°C or more and 48°C or less. The film thickness is preferably, for example, 0.3 μm or more and 15 μm or less.

[0381] Boehmite treatment can be performed, for example, by immersion in pure water at a temperature above 90°C and below 100°C for 5 to 60 minutes, or by contact in heated steam at a temperature above 90°C and below 120°C for 5 to 60 minutes. The film thickness is preferably, for example, 0.1 μm or more and 5 μm or less. Further anodizing can be performed using electrolyte solutions with low film solubility, such as adipic acid, boric acid, borates, phosphates, phthalates, maleates, benzoates, tartrates, and citrates.

[0382] [Undercoat]

[0383] The undercoat layer may be, for example, a layer containing inorganic particles and a binding resin.

[0384] As inorganic particles, for example, the resistance (volume resistivity) of powder is 1×10⁻⁶. 2 Ω·cm or more and 1×10 11 Inorganic particles below Ω·cm.

[0385] Among them, inorganic particles having the above-mentioned resistance values ​​are preferably metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles, and zinc oxide particles are particularly preferred.

[0386] The specific surface area of ​​inorganic particles based on the BET method is preferably, for example, 10 m². 2 / g or more.

[0387] The volume average particle size of the inorganic particles is preferably 50 nm or more and 2000 nm or less (preferably 60 nm or more and 1000 nm or less).

[0388] The content of inorganic particles, relative to the bonding resin, is preferably 10% by mass or more and 80% by mass or less, more preferably 40% by mass or more and 80% by mass or less.

[0389] Inorganic particles can be used for surface treatment. Two or more types of inorganic particles with different surface treatments or different particle sizes can be mixed together.

[0390] Examples of surface treatment agents include silane coupling agents, titanate coupling agents, aluminum coupling agents, and surfactants. In particular, silane coupling agents are preferred, and silane coupling agents having an amino group are more preferred.

[0391] Examples of amino-containing silane coupling agents include 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, but are not limited to these.

[0392] Two or more silane coupling agents can be used in combination. For example, an amino-containing silane coupling agent can be used in combination with other silane coupling agents. Other silane coupling agents include, but are not limited to, vinyltrimethoxysilane, 3-methacryloyloxypropyltris(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.

[0393] Surface treatment methods based on surface treatment agents can be any known method, including either dry or wet methods.

[0394] The amount of surface treatment agent relative to the inorganic particles is preferably 0.5% by mass or more and 10% by mass or less.

[0395] From the viewpoint of improving the long-term stability of electrical properties and carrier blocking properties, the lower coating preferably contains, for example, an electron acceptor compound (acceptor compound) along with the inorganic particles.

[0396] Examples of electron-accepting compounds include compounds with anthraquinone structures; quinones such as chloroquinone and tetrabromo-p-benzoquinone; dimethyl tetracyanoquinone 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; xanthonesone compounds; thiophene compounds; biphenylquinone compounds such as 3,3',5,5'-tetra-tert-butylbiphenylquinone; benzophenone compounds; and isoelectronic transport substances.

[0397] Especially as electron-accepting compounds, compounds having an anthraquinone structure are preferred, for example. Compounds having an anthraquinone structure are preferably hydroxyanthraquinone compounds, aminoanthraquinone compounds, aminohydroxyanthraquinone compounds, etc., and more specifically, anthraquinones, alizarins, quinone alizarins, anthraquinone oleuropein, rutin, and their derivatives are preferred.

[0398] Electron-accepting compounds can be dispersed in the undercoat along with inorganic particles, or they can be contained in the undercoat in a state of being attached to the surface of inorganic particles.

[0399] Methods for attaching electron-accepting compounds to the surface of inorganic particles include, for example, dry or wet methods.

[0400] A dry method, for example, involves directly adding an electron-accepting compound or an electron-accepting compound dissolved in an organic solvent while stirring inorganic particles using a mixer with high shear force, and then spraying it together with dry air or nitrogen, thereby causing the electron-accepting compound to adhere to the surface of the inorganic particles. When adding or spraying the electron-accepting compound, it is preferable to do so at a temperature below the boiling point of the solvent. After adding or spraying the electron-accepting compound, sintering can be performed at a temperature above 100°C. There are no particular limitations on the temperature and time of sintering, as long as the electron photographic properties are obtained.

[0401] Wet processes, for example, involve dispersing inorganic particles in a solvent using a mixer, ultrasonic disperser, sand mill, grinder, or ball mill. An electron-accepting compound is added, and the mixture is stirred or dispersed. The solvent is then removed, allowing the electron-accepting compound to adhere to the surface of the inorganic particles. Solvent removal methods include filtration or evaporation. After solvent removal, sintering can be performed at temperatures above 100°C. The temperature and time for sintering are not particularly limited as long as the electron imaging properties are obtained. In wet processes, the moisture content of the inorganic particles can be removed before adding the electron-accepting compound. Examples include removing moisture while stirring and heating in a solvent, or removing it through azeotropic mixing with the solvent.

[0402] The attachment of electron-receiving compounds can be performed before or after surface treatment of inorganic particles using a surface treatment agent, or the attachment of electron-receiving compounds can be performed simultaneously with surface treatment using a surface treatment agent.

[0403] The content of the electron-accepting compound is preferably 0.01% by mass or more and 20% by mass or less, and more preferably 0.01% by mass or more and 10% by mass or less, relative to inorganic particles.

[0404] Examples of known polymeric compounds used as adhesive resins in the undercoat include acetal resins (such as polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, unsaturated polyester resins, methacrylic acid resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, urea resins, phenolic resins, phenolic-formaldehyde resins, melamine resins, urethane resins, alkyd resins, and epoxy resins; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; organotitanium compounds; and silane coupling agents.

[0405] Examples of adhesive resins used in the undercoat include charge-transporting resins with charge-transporting groups and conductive resins (e.g., polyaniline).

[0406] The adhesive resin used in the lower coating layer is preferably a resin that is insoluble in the coating solvent, and more preferably a resin obtained by reacting a curing agent with at least one resin selected from the group consisting of thermosetting resins such as urea resin, phenolic resin, phenolic-formaldehyde resin, melamine resin, urethane resin, unsaturated polyester resin, alkyd resin, and epoxy resin; polyamide resin, polyester resin, polyether resin, methacrylic resin, acrylic resin, polyvinyl alcohol resin, and polyvinyl alcohol acetal resin.

[0407] When using two or more adhesive resins in combination, the mixing ratio should be set as needed.

[0408] To improve electrical properties, environmental stability, and image quality, various additives can be included in the undercoat.

[0409] Examples of additives include polycyclic condensation pigments, azo pigments, zirconium chelates, titanium chelates, aluminum chelates, titanium alkoxides, organotitanium compounds, and silane coupling agents. As mentioned earlier, silane coupling agents are used for surface treatment of inorganic particles, but they can also be added as additives to undercoatings.

[0410] Examples of silane coupling agents used as additives include vinyltrimethoxysilane, 3-methacryloyloxypropyltris(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.

[0411] Examples of zirconium chelate compounds include zirconium butoxide, ethyl zirconium acetoacetate, zirconium triethanolamine, zirconium acetylacetone butoxide, zirconium 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.

[0412] Examples of titanium chelate compounds include tetraisopropyl titanate, tetrabutyl titanate, tetrabutyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetone, polyacetylacetone titanium, octanediol titanium, titanium ammonium lactate, titanium lactate, titanium ethyl lactate, titanium triethanolamine, and titanium polyhydroxystearate.

[0413] Examples of aluminum chelate compounds include aluminum isopropoxide, aluminum monobutoxydiisopropoxide, aluminum butoxide, aluminum diacetoacetate diisopropoxide, and aluminum triacetoacetate.

[0414] These additives can be used alone or as a mixture or condensation polymer of multiple compounds.

[0415] The undercoat is preferably coated with a Vickers hardness of 35 or higher.

[0416] To suppress interference ripples, the surface roughness (ten-point average roughness) of the lower coating is preferably adjusted to, for example, 1 / (4n) to 1 / 2 of the wavelength λ of the laser used for exposure (where n is the refractive index of the upper layer).

[0417] To adjust surface roughness, resin particles can be added to the undercoat. Examples of resin particles include silicone resin particles and cross-linked polymethyl methacrylate resin particles. Furthermore, to adjust surface roughness, the surface of the undercoat can be ground. Examples of grinding methods include polishing, sandblasting, wet grinding, and grinding.

[0418] There are no particular limitations on the formation of the undercoat, and known formation methods can be used. However, for example, the formation of the undercoat is carried out by adding the above-mentioned components to the solvent to form a coating film of the coating liquid, drying the coating film, and heating as needed.

[0419] As solvents used to prepare coating liquids for forming the undercoat, known organic solvents can be cited, such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, ketol solvents, ether solvents, ester solvents, etc.

[0420] Specifically, examples of these solvents include, for instance, 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, toluene, and other common organic solvents.

[0421] Methods for dispersing inorganic particles during the preparation of coating liquid for forming a lower coating include, for example, known methods such as roller mills, ball mills, vibratory ball mills, grinding mills, sand mills, colloid mills, and paint mixers.

[0422] Methods for applying a coating liquid for forming an undercoat onto a conductive substrate include, for example, scraper coating, wire rod coating, spraying, dip coating, bead coating, air knife coating, and curtain coating.

[0423] The thickness of the lower coating is preferably 15 μm or more, and more preferably set in the range of 20 μm or more and 50 μm or less.

[0424] [Middle Layer]

[0425] The intermediate layer may be, for example, a layer containing resin. Examples of resins used in the intermediate layer include acetal resins (such as polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, methacrylic acid resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenolic-formaldehyde resins, melamine resins, and other polymeric compounds.

[0426] The intermediate layer can be a layer containing an organometallic compound. Examples of organometallic compounds used as intermediate layers include those containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.

[0427] The compounds used in these intermediate layers can be used alone or as a mixture of multiple compounds or as condensation polymers.

[0428] The intermediate layer is preferably a layer containing an organometallic compound containing zirconium or silicon atoms.

[0429] There are no particular limitations on the formation of the intermediate layer, and known formation methods can be used. However, for example, the intermediate layer is formed by adding the above-mentioned components to the solvent to form a coating film of the coating liquid, drying the coating film, and heating as needed.

[0430] As a coating method for forming the intermediate layer, conventional methods such as dip coating, push coating, bar coating, spraying, scraper coating, air knife coating, and curtain coating can be used.

[0431] The thickness of the intermediate layer is preferably set in the range of 0.1 μm or more and 3 μm or less. The intermediate layer can be used as the lower coating layer.

[0432] <Image forming apparatus, processing box>

[0433] The image forming apparatus according to this embodiment includes an electrophotographic photosensitive body, a charging device for charging the surface of the electrophotographic photosensitive body, an electrostatic latent image forming device for forming an electrostatic latent image on the surface of the charged electrophotographic photosensitive body, a developing device for forming a toner image by developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive body with a developing agent containing a toner, a transfer device for transferring the toner image onto the surface of a recording medium, and a cleaning device for cleaning the surface of the electrophotographic photosensitive body. Furthermore, the electrophotographic photosensitive body according to this embodiment is applicable.

[0434] In the image forming apparatus of this embodiment, the cleaning device has a cleaning blade that contacts the outer peripheral surface of the photoreceptor, and the cleaning blade cleans the surface of the photoreceptor after the toner image is transferred and before it is charged.

[0435] The image forming apparatus according to this embodiment is applicable to the following known image forming apparatuses: an apparatus having a fixing apparatus for fixing a toner image transferred to the surface of a recording medium; an apparatus for a direct transfer method that directly transfers a toner image formed on the surface of an electrophotographic photosensitive body to the recording medium; an apparatus for an intermediate transfer method that transfers a toner image formed on the surface of an electrophotographic photosensitive body to the surface of an intermediate transfer body in one step, and then transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium in a second step; an apparatus having an antistatic apparatus for irradiating the surface of an electrophotographic photosensitive body with antistatic light after the toner image is transferred but before it is charged to eliminate static electricity; and an apparatus having an electrophotographic photosensitive body heating member for raising the temperature of the electrophotographic photosensitive body and lowering the relative temperature, etc.

[0436] In the case of an intermediate transfer method apparatus, the transfer apparatus may have a structure that includes an intermediate transfer body for transferring a toner image onto a surface, a primary transfer apparatus for transferring a toner image formed on the surface of an electrophotographic photosensitive body to the surface of the intermediate transfer body in one step, and a secondary transfer apparatus for transferring the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium in a second step.

[0437] The image forming apparatus described in this embodiment can be either a dry developing image forming apparatus or a wet developing image forming apparatus (a developing method that utilizes liquid developer).

[0438] In the image forming apparatus according to this embodiment, for example, the portion including the electrophotographic photosensitive element can be a cassette structure (processing cassette) that is detachable from the image forming apparatus. As the processing cassette, for example, a processing cassette including the electrophotographic photosensitive element according to this embodiment is preferably used. In addition to the electrophotographic photosensitive element, the processing cassette may also include at least one selected from the group consisting of a charging device, an electrostatic latent image forming apparatus, a developing apparatus, and a transfer apparatus.

[0439] The following describes an example of the image forming apparatus according to this embodiment, but it is not limited thereto. The main parts shown in the figures will be described, while the description of other parts will be omitted.

[0440] Figure 2 This is a schematic structural diagram illustrating an example of the image forming apparatus according to this embodiment.

[0441] like Figure 2 As shown, the image forming apparatus 100 according to this embodiment includes a processing cartridge 300 having an electrophotographic photosensitive element 7, an exposure apparatus 9 (an example of an electrostatic latent image forming apparatus), a transfer apparatus 40 (a primary transfer apparatus), and an intermediate transfer body 50. In the image forming apparatus 100, the exposure apparatus 9 is positioned to expose the electrophotographic photosensitive element 7 through the opening of the processing cartridge 300, and the transfer apparatus 40 is positioned opposite the electrophotographic photosensitive element 7 across the intermediate transfer body 50, with a portion of the intermediate transfer body 50 in contact with the electrophotographic photosensitive element 7. Although not shown, a secondary transfer apparatus is also included to transfer the toner image transferred to the intermediate transfer body 50 to a recording medium (e.g., paper). The intermediate transfer body 50, the transfer apparatus 40 (a primary transfer apparatus), and the secondary transfer apparatus (not shown) are examples of transfer apparatuses.

[0442] Figure 2The processing cartridge 300 integrally supports the electrophotographic photoreceptor 7, the charging device 8 (an example of the charging device), the developing device 11 (an example of the developing device), and the cleaning device 13 (an example of the cleaning device) within the housing. The cleaning device 13 has a cleaning blade (an example of a cleaning component) 131, which is configured to contact the surface of the electrophotographic photoreceptor 7. The cleaning component may be a conductive or insulating fibrous component instead of the cleaning blade 131, and may be used alone or in conjunction with the cleaning blade 131.

[0443] exist Figure 2 In the example shown, as an image forming apparatus, a fibrous component 132 (roller-shaped) is provided for supplying lubricant 14 to the surface of the electrophotographic photosensitive element 7, and a fibrous component 133 (flat brush-shaped) is provided for auxiliary cleaning, but they can be configured as needed.

[0444] The structure of the image forming apparatus according to this embodiment will be described below.

[0445] -Electrified devices-

[0446] The charging device 8 can be a contact-type charging device where the charged component is in contact with the peripheral surface of the photoreceptor, or a non-contact-type charging device where the charged component is not in contact with the peripheral surface of the photoreceptor. The effect of the image forming apparatus according to this embodiment (not easily contaminated by the charged component over a long period of time) is particularly significant in the contact-type charging device.

[0447] As the charging device 8, contact-type charging components that utilize conductive or semi-conductive materials, such as charging rollers, charging brushes, charging films, charging rubber scrapers, and charging hoses, can be used. Furthermore, non-contact roller belt chargers, grid corona tube belt chargers utilizing corona discharge, or corona tube belt chargers, and other known charging devices, can also be used.

[0448] -Exposure device-

[0449] Examples of exposure devices 9 include optical systems that expose semiconductor lasers, LED lights, liquid crystal shutter lights, etc., onto the surface of an electrophotographic photosensitive object 7 to form a predetermined pattern. The wavelength of the light source is set within the spectral sensitivity range of the electrophotographic photosensitive object. Near-infrared light with an oscillation wavelength around 780 nm is the most common wavelength for semiconductor lasers. However, it is not limited to this wavelength; lasers with an oscillation wavelength in the 600 nm band or blue lasers, or lasers with an oscillation wavelength in the range of 400 nm to 450 nm, can be used. Furthermore, surface-emitting laser sources capable of outputting multiple beams for forming color images are also effective.

[0450] -Developing apparatus-

[0451] As a developing apparatus 11, examples include conventional developing apparatuses that perform development by contact or non-contact with the developer. There are no particular limitations on the developing apparatus 11 as long as it possesses the aforementioned functions, and it can be selected according to the purpose. For example, known developing machines that use brushes, rollers, etc., to adhere single-component or two-component developers to the electrophotographic photosensitive element 7 can be cited. Among these, a developing machine that uses a developing roller to hold the developer on the surface is preferred, for example.

[0452] The developer used in the developing apparatus 11 can be a single-component developer containing only a toner, or a two-component developer containing both a toner and charge carriers. Furthermore, the developer can be magnetic or non-magnetic. Commonly known developers are acceptable.

[0453] -Cleaning Device-

[0454] The cleaning device 13 is a cleaning scraper device equipped with a cleaning scraper 131. In addition to the cleaning scraper method, a brush cleaning method or a simultaneous developing and cleaning method can also be used.

[0455] -Transfer Device-

[0456] As a transfer device 40, examples include contact transfer belt appliances that use belts, rollers, films, rubber squeegees, etc.; grid corona tube transfer belt appliances that utilize corona discharge; and corona tube transfer belt appliances, which are known in themselves.

[0457] -Intermediate Transfer Material-

[0458] As the intermediate transfer body 50, a strip-shaped transfer body (intermediate transfer tape) containing polyimide, polyamide-imide, polycarbonate, polyarylate, polyester, rubber, etc., which are endowed with semi-conductivity is used. Furthermore, in addition to the strip shape, a drum-shaped transfer body can also be used as the intermediate transfer body.

[0459] Figure 3 This is a schematic structural diagram showing another example of the image forming apparatus according to this embodiment.

[0460] Figure 3 The image forming apparatus 120 shown is a multicolor image forming apparatus equipped with four processing cartridges 300 arranged in series. In the image forming apparatus 120, four processing cartridges 300 are arranged side by side on the intermediate transfer body 50, and a structure is formed in which one electrophotographic photosensitive element is used for each color. Except for the series arrangement, the image forming apparatus 120 has the same structure as the image forming apparatus 100.

[0461] Example

[0462] The following describes the implementation of the invention in detail with reference to the embodiments, but the implementation of the invention is not limited to these embodiments in any way.

[0463] Unless otherwise specified, “parts” and “%” are quality standards in the following description.

[0464] Unless otherwise specified, the synthesis, processing, and manufacturing processes are carried out at room temperature (25℃±3℃).

[0465] <Synthesis of Polyarylate Resins>

[0466] Polyaryl ester resins PA1, PA2 and PA8 were synthesized.

[0467] Table 1 shows the units and composition that make up the polyarylate resin.

[0468] The A2-3 examples listed in Table 1 are specific examples of the dicarboxylic acid units (A) that have been described.

[0469] The B1-2 and other examples listed in Table 1 are specific examples of the diol units (B) that have been described.

[0470] [Table 1]

[0471]

[0472] <The Manufacturing of Photoreceptors>

[0473] The following materials were prepared as materials for forming the charge transport layer.

[0474] • Charge transport material CTM-1

[0475] • Charge transport material CTM-2

[0476] [Chemical Formula 41]

[0477]

[0478] • Polycarbonate resin PC1: The following compounds have a viscosity-average molecular weight of 50,000, and the values ​​in the following formulas represent the molar ratio.

[0479] [Chemical Formula 42]

[0480]

[0481] • Polycarbonate resin PC3: A polymeric compound having repeating structural units represented by the following formula (viscosity-average molecular weight: 40,000)

[0482] [Chemical Formula 43]

[0483]

[0484] • Polyvinyl butyral resin: viscosity-average molecular weight 66,000, manufactured by S-LEC BH-S, SEKISUI CHEMICALCO.,LTD.

[0485] Phenolic compound PH3: ADEKA STAB AO-80, manufactured by ADEKA CORPORATION.

[0486] (Example 1)

[0487] -Formation of the undercoat-

[0488] 3.5 parts of butyral resin (trade name: S-LEC BM-1, manufactured by SEKISUI CHEMICAL CO.,LTD.) and 41 parts of methyl ethyl ketone were mixed and dissolved. 10 parts of curing agent (blocked isocyanate, trade name: SUMIDUR 3175, manufactured by Sumitomo Bayer Urethane Co.,Ltd.), 45.5 parts of zinc oxide (trade name: SMZ-017N, manufactured by TAYCACORPORATION) surface-treated with silane coupling agent (trade name: KBM603, manufactured by Shin-Etsu Chemical Co.,Ltd.), and 0.27 parts of the following compound were added and stirred. The mixture was then dispersed using 1 mm diameter glass beads in a sand mill for 2 hours. Furthermore, 0.01 parts of dioctyltin dilaurate and 2 parts of silicone resin particles (trade name: TOSPEARL145, manufactured by GE Toshiba Silicones Co., Ltd.) were added and stirred to obtain a coating solution for forming the lower coating layer. The coating solution for forming the lower coating layer was applied to the outer peripheral surface of the conductive substrate by dip coating method, and dried and cured at 170°C for 40 minutes to form a lower coating layer with a thickness of 20 μm.

[0489] [Chemical Formula 44]

[0490]

[0491] -Formation of the charge generation layer-

[0492] A mixture consisting of 14 parts of gallium phthalocyanine chloride (with diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.4°, 16.6°, 25.5°, and 28.3° in X-ray diffraction spectra using CuKα characteristic X-rays), 12 parts of 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 using glass beads with a diameter of 1 mm and milled in a sand mill for 4 hours. 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 for forming the charge-generating layer was impregnated onto a lower coating layer and dried at room temperature to form a charge-generating layer with a thickness of 0.25 μm.

[0493] -Formation of the charge transport layer-

[0494] • Charge transport material CTM-1: 47 parts

[0495] • Charge transport material CTM-2: 20 parts

[0496] • Polyarylate resin (PA1): 29 parts (30% of total resin)

[0497] • Polycarbonate resin (PC1): 67 parts (70% of total resin)

[0498] Phenolic compounds (PH3): 4.9 parts

[0499] Tetrahydrofuran: 570 samples

[0500] Toluene: 57 parts

[0501] The above materials were stirred and mixed to obtain a coating solution for forming a charge transport layer. The coating solution was then applied onto the charge generation layer and dried at 143°C for 30 minutes to form a charge transport layer with a thickness of 33 μm. Thus, photoreceptor 1 was obtained.

[0502] (Examples 2 to 10 and Comparative Examples 1 to 4)

[0503] The composition of each layer was changed as described in Table 2, and the photoreceptor was otherwise obtained in the same manner as in Example 1.

[0504] <Evaluation of the ability to suppress localized degradation of electrical properties>

[0505] A photoreceptor was mounted in an electrophotographic image forming apparatus (Xerox 700 Digital ColorPress, manufactured by Xerox Corporation). Using a surface potentiometer (TREK Corporation, TREK334), a surface potential probe was placed 1 mm from the surface of the photoreceptor. The electrical characteristics at nine points along the axial direction of the test drum (four points each at 20 mm intervals above and below the central point) were evaluated as follows. After charging the image forming apparatus to -700V and setting the post-exposure potential (VL) to -230V, 200,000 full-page midtone images with an image density of 30% were printed on A4-sized paper under a high temperature and high humidity environment (temperature 28°C and relative humidity 85%). The surface potential was then measured using the surface potentiometer (surface potential measurement was performed after the same charge-exposure treatment as the initial measurement), and the results were categorized as follows (the initial / post-200,000-image VL difference at each point is preferably within 10V; the more points with this difference, the more stable the electrical characteristics).

[0506] The evaluation criteria are shown below.

[0507] A: At point 9 / 9, the difference between the initial surface potential and the long-term surface potential is within 5V.

[0508] A-: 9 / 9 points, initial surface potential - long-term surface potential difference exceeds 5V but is within 10V.

[0509] B+: 8 / 9 points, the difference between the initial surface potential and the long-term surface potential is within 10V.

[0510] B: At point 7 / 9, the difference between the initial surface potential and the long-term surface potential is within 10V.

[0511] B-: At point 6 / 9, the difference between the initial surface potential and the long-term surface potential difference is within 10V.

[0512] C: 5 to 3 / 9 points, the difference between the initial surface potential and the long-term surface potential is within 10V.

[0513] D: Points 2 to 1 / 9, the difference between the initial surface potential and the long-term surface potential is within 10V.

[0514] E: 0 / 9 points, the difference between the initial surface potential and the long-term surface potential is within 10V.

[0515] The evaluation results are shown in Table 2.

[0516]

[0517] As shown in Table 2, the electrophotographic photoresists of Examples 1 to 10 exhibit superior suppression of localized deterioration of electrical properties after long-term printing compared to the electrophotographic photoresists of Comparative Examples 1 to 4.

[0518] (1) An electrophotographic photosensitive material comprising: a conductive substrate; and a stacked photosensitive layer disposed on the conductive substrate and having a charge generating layer and a charge transport layer, wherein the charge transport layer contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B), the charge generating layer contains gallium chlorophthalocyanine as a charge generating material, and the content of the binder resin in the charge generating layer / the total content of the binder resin and the charge generating material is greater than 0.4 and less than 0.7.

[0519] [Chemical Formula 45]

[0520]

[0521] In equation (A), Ar A1 and Ar A2 Each is an aromatic ring that can have substituents, L A It is a single bond or a divalent linker, n A1 It can be 0, 1, or 2.

[0522] In equation (B), Ar B1 and Ar B2 Each is an aromatic ring that can have substituents, L B It is a single bond, an oxygen atom, a sulfur atom, or -C(Rb) 1 (Rb) 2 )-,n B1 It can be 0, 1, or 2. Rb 1 and Rb 2 Rb is independently composed of hydrogen atoms, an alkyl group having 1 or more but less than 20 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an aralkyl group having 7 or more but less than 20 carbon atoms. 1 With Rb 2 They can bond together to form cyclic alkyl groups.

[0523] (2) According to the electrophotographic photosensitive material of (1), wherein the content of the adhesive resin in the charge generating layer / the total content of the adhesive resin and the charge generating material is greater than 0.43 and less than 0.60.

[0524] (3) The electrophotographic photosensitive material according to (1) or (2), wherein the dicarboxylic acid unit represented by formula (A) comprises at least one selected from the group consisting of the dicarboxylic acid unit (A1) represented by formula (A2), the dicarboxylic acid unit (A3) represented by formula (A4), the dicarboxylic acid unit (A5) represented by formula (A5).

[0525] [Chemical Formula 46]

[0526]

[0527] In equation (A1), n 101 n is an integer greater than or equal to 0 and less than or equal to 4. 101 Ra 101 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0528] In equation (A2), n 201 and n 202 Each of the following is an independent integer greater than 0 and less than 4, n 201 Ra 201 and n 202 Ra 202 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0529] In equation (A3), n 301 and n 302 Each of the following is an independent integer greater than 0 and less than 4, n 301 Ra 301 and n 302 Ra 302 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0530] In equation (A4), n 401 n is an integer greater than 0 and less than 6. 401 Ra 401 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0531] In equation (A5), n 501 n 502 and n 503 Each of the following is an independent integer greater than 0 and less than 4, n501 Ra 501 n 502 Ra 502 and n 503 Ra 503 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

[0532] (4) The electrophotographic photosensitive unit according to any one of (1) to (3), wherein the diol unit represented by formula (B) comprises at least one selected from the group consisting of the diol unit (B1) represented by formula (B1), the diol unit (B2) represented by formula (B2), the diol unit (B3) represented by formula (B3), the diol unit (B4) represented by formula (B4), the diol unit (B5) represented by formula (B5), the diol unit (B6) represented by formula (B6), the diol unit (B7) represented by formula (B7), and the diol unit (B8) represented by formula (B8).

[0533] [Chemical Formula 47]

[0534]

[0535] [Chemical Formula 48]

[0536]

[0537] In equation (B1), Rb 101 Branched alkyl groups with 4 or more but less than 20 carbon atoms, Rb 201 Rb is an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms. 401 、Rb 501 、Rb 801 and Rb 901 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0538] In equation (B2), Rb 102 Rb is a straight-chain alkyl group with 4 or more but less than 20 carbon atoms. 202 Rb is an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms. 402 、Rb 502 、Rb 802 and Rb 902 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0539] In equation (B3), Rb 113 and Rb213 Each of the following is independently a hydrogen atom, a straight-chain alkyl group having 1 or more but less than 3 carbon atoms, an alkoxy group having 1 or more but less than 4 carbon atoms, or a halogen atom, where d is an integer between 7 and 15, and Rb 403 、Rb 503 、Rb 803 and Rb 903 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0540] In equation (B4), Rb 104 and Rb 204 Each is independently an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms, Rb 404 、Rb 504 、Rb 804 and Rb 904 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0541] In equation (B5), Ar 105 Rb is an aryl group having 6 or more but less than 12 carbon atoms, or an aralkyl group having 7 or more but less than 20 carbon atoms. 205 Rb is an alkyl group having 1 or more hydrogen atoms and 3 or fewer carbon atoms. 405 、Rb 505 、Rb 805 and Rb 905 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0542] In equation (B6), Rb 116 and Rb 216 Each of the following is independently a hydrogen atom, a straight-chain alkyl group having 1 or more but less than 3 carbon atoms, an alkoxy group having 1 or more but less than 4 carbon atoms, or a halogen atom, where e is an integer of 4 or more but less than 6, and Rb 406 、Rb 506 、Rb 806 and Rb 906 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0543] In equation (B7), Rb 407 、Rb 507 、Rb 807 and Rb 907 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0544] In equation (B8), Rb 408 、Rb 508 、Rb 808 and Rb 908 Each is independently a hydrogen atom, an alkyl group having 1 or more but less than 4 carbon atoms, an alkoxy group having 1 or more but less than 6 carbon atoms, or a halogen atom.

[0545] (5) The electrophotographic photosensitive material according to any one of (1) to (4), wherein the adhesive resin in the charge generating layer is a vinyl acetate resin or a polyvinyl butyral resin.

[0546] (6) The electrophotographic photosensitive material according to any one of (1) to (5), wherein the adhesive resin in the charge generating layer is a vinyl chloride-vinyl acetate copolymer or a polyvinyl butyral resin.

[0547] (7) The electrophotographic photosensitive material according to any one of (1) to (6), wherein the charge transport layer further comprises polycarbonate resin.

[0548] (8) A processing cartridge comprising any one of (1) to (7) an electrophotographic photosensitive element, the processing cartridge being detachable from an image forming apparatus.

[0549] (9) An image forming apparatus comprising:

[0550] The electrophotographic photosensitive material as described in any one of (1) to (7);

[0551] A charging device is used to charge the surface of the electrophotographic photosensitive element.

[0552] An electrostatic latent image forming apparatus forms an electrostatic latent image on the surface of the electrophotographic photoreceptor that has been charged.

[0553] A developing apparatus that develops an electrostatic latent image formed on the surface of the electrophotographic photoreceptor using a developing agent containing a toner to form a toner image; and

[0554] A transfer device that transfers the toner image onto the surface of a recording medium.

[0555] According to the invention involved in (1), compared with the case where the charge transport layer contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B), and the charge generation layer contains gallium chlorophthalocyanine as a charge generation material, and the value of the content of the binder resin in the charge generation layer / the total content of the binder resin and the charge generation material is 0.4 or less or 0.7 or more, an electrophotographic photosensitive material with excellent local deterioration inhibition of electrical properties after long-term printing is provided.

[0556] According to the invention involved in (2), compared with the case where the content of the adhesive resin in the charge generation layer / the total content of the adhesive resin and the charge generation material is 0.43 or less or 0.60 or more, an electrophotographic photosensitive material with better suppression of local deterioration of electrical properties after long-term printing is provided.

[0557] According to the invention involved in (3), compared with the case where the dicarboxylic acid unit represented by formula (A) does not contain at least one selected from the group consisting of the dicarboxylic acid unit (A1) represented by formula (A2), the dicarboxylic acid unit (A3) represented by formula (A4), the dicarboxylic acid unit (A4) represented by formula (A5), and the dicarboxylic acid unit (A5) represented by formula (A5), an electrophotographic photosensitive material with superior local deterioration inhibition of electrical properties after long-term printing is provided.

[0558] According to the invention involved in (4), compared with the case where the diol unit represented by formula (B) does not contain at least one selected from the group consisting of diol unit (B1) represented by formula (B1), diol unit (B2) represented by formula (B2), diol unit (B3) represented by formula (B3), diol unit (B4) represented by formula (B4), diol unit (B5) represented by formula (B5), diol unit (B6) represented by formula (B6), diol unit (B7) represented by formula (B7) and diol unit (B8) represented by formula (B8), an electrophotographic photosensitive material with superior local deterioration suppression of electrical properties after long-term printing is provided.

[0559] According to the invention involved in (5), compared with the case where the adhesive resin in the charge generation layer is polyester resin, an electrophotographic photosensitive material with better suppression of local deterioration of electrical properties after long-term printing is provided.

[0560] According to the invention involved in (6), compared with the case where the adhesive resin in the charge generation layer is a vinyl acetate homopolymer, an electrophotographic photosensitive material with better suppression of local deterioration of electrical properties after long-term printing is provided.

[0561] According to the invention involved in (7), compared with the case where the charge transport layer does not contain polycarbonate resin, an electrophotographic photosensitive material with better suppression of local deterioration of electrical properties after long-term printing is provided.

[0562] According to the invention involved in (8) or (9), compared with the case where the charge transport layer of the electrophotographic photoreceptor contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B), and the charge generation layer contains gallium chlorophthalocyanine as a charge generation material, and the value of the content of the binder resin in the charge generation layer / the total content of the binder resin and the charge generation material is 0.4 or less or 0.7 or more, a processing cartridge or image forming apparatus with excellent suppression of local deterioration of electrical properties after long-term printing is provided.

[0563] The embodiments of the present invention described above are provided for illustrative purposes. Furthermore, these embodiments do not encompass the entirety of the invention, nor do they limit the invention to the disclosed methods. It will be apparent to those skilled in the art that various modifications and variations will be readily understood. These embodiments were chosen and described to most readily explain the principles and applications of the invention. Thus, those skilled in the art can understand the invention through various modifications that are assumed to be optimized for specific uses of various embodiments. The scope of the invention is defined by the foregoing claims and their equivalents.

Claims

1. An electrophotographic photosensitive material, comprising: Conductive substrate; and A stacked photosensitive layer is disposed on the conductive substrate and has a charge generation layer and a charge transport layer, wherein... The charge transport layer contains a polyarylate resin having a dicarboxylic acid unit (A) represented by formula (A) and a diol unit (B) represented by formula (B). The charge-generating layer contains gallium chlorophthalocyanine as the charge-generating material. The ratio of the content of the bonding resin in the charge-generating layer to the total content of the bonding resin and the charge-generating material is greater than 0.4 and less than 0.

7. [Chemical Formula 1] In equation (A), Ar A1 and Ar A2 Each is an aromatic ring that can have substituents, L A It is a single bond or a divalent linker, n A1 It can be 0, 1, or 2; In equation (B), Ar B1 and Ar B2 Each is an aromatic ring that can have substituents, L B It is a single bond, an oxygen atom, a sulfur atom, or -C(Rb) 1 (Rb) 2 )-,n B1 It can be 0, 1, or 2; Rb 1 and Rb 2 Rb is independently composed of hydrogen atoms, an alkyl group having 1 or more but less than 20 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an aralkyl group having 7 or more but less than 20 carbon atoms. 1 With Rb 2 They can bond together to form cyclic alkyl groups.

2. The electrophotographic photosensitive material according to claim 1, wherein, The ratio of the content of the bonding resin in the charge-generating layer to the total content of the bonding resin and the charge-generating material is greater than 0.43 and less than 0.

60.

3. The electrophotographic photosensitive material according to claim 1 or 2, wherein, The dicarboxylic acid unit represented by formula (A) comprises at least one selected from the group consisting of dicarboxylic acid units (A1) represented by formula (A2), dicarboxylic acid units (A3) represented by formula (A4), and dicarboxylic acid units (A5) represented by formula (A5). [Chemical Formula 2] In equation (A1), n 101 n is an integer greater than 0 and less than 4. 101 Ra 101 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms; In equation (A2), n 201 and n 202 Each of the following is an independent integer greater than 0 and less than 4, n 201 Ra 201 and n 202 Ra 202 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms; In equation (A3), n 301 and n 302 Each of the following is an independent integer greater than 0 and less than 4, n 301 Ra 301 and n 302 Ra 302 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms; In equation (A4), n 401 n is an integer greater than 0 and less than 6. 401 Ra 401 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms; In equation (A5), n 501 n 502 and n 503 Each of the following is an independent integer greater than 0 and less than 4, n 501 Ra 501 n 502 Ra 502 and n 503 Ra 503 Each is independently an alkyl group having 1 or more but less than 10 carbon atoms, an aryl group having 6 or more but less than 12 carbon atoms, or an alkoxy group having 1 or more but less than 6 carbon atoms.

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

5. The electrophotographic photosensitive material according to any one of claims 1 to 4, wherein, The adhesive resin in the charge-generating layer is a vinyl acetate-based resin or a polyvinyl butyral-based resin.

6. The electrophotographic photosensitive material according to any one of claims 1 to 5, wherein, The adhesive resin in the charge-generating layer is a vinyl chloride-vinyl acetate copolymer or a polyvinyl butyral resin.

7. The electrophotographic photosensitive material according to any one of claims 1 to 6, wherein, The charge transport layer also contains polycarbonate resin.

8. A processing cartridge comprising the electrophotographic photosensitive element as described in any one of claims 1 to 7. The processing box is mounted and dismounted from the image forming apparatus.

9. An image forming apparatus comprising: Electrophotographic photoresist according to any one of claims 1 to 7; A charging device is used to charge the surface of the electrophotographic photosensitive element. An electrostatic latent image forming apparatus forms an electrostatic latent image on the surface of the electrophotographic photoreceptor that has been charged. A developing apparatus that develops an electrostatic latent image formed on the surface of the electrophotographic photoreceptor using a developing agent containing a toner to form a toner image. and A transfer device that transfers the toner image onto the surface of a recording medium.

Images