EP-4741936-A1 - ELECTROPHOTOGRAPHIC PHOTORECEPTOR, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS

EP4741936A1EP 4741936 A1EP4741936 A1EP 4741936A1EP-4741936-A1

Abstract

An electrophotographic photoreceptor includes a conductive substrate, and a photosensitive layer disposed on the conductive substrate, in which an outermost surface layer contains a charge transport material, a polyarylate resin having at least one dicarboxylic acid unit selected from the group composed of a dicarboxylic acid unit (A2) represented by Formula (A2), a dicarboxylic acid unit (A3) represented by Formula (A3), a dicarboxylic acid unit (A4) represented by Formula (A4), and a dicarboxylic acid unit (A5) represented by Formula (A5) and a diol unit represented by Formula (B), and a polycarbonate resin, and a weight-average molecular weight MwA of the polyarylate resin and a weight-average molecular weight MwB of the polycarbonate resin satisfy -14 ≤ 100 × (MwA - MwB)/MwA ≤ 14, in Formula (A2), n 201 and n 202 are each independently an integer of 0 or greater and 4 or less, and n 201 pieces of Ra 201 's and n 202 pieces of Ra 202 's are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, in Formula (A3), n 301 and n 302 are each independently an integer of 0 or greater and 4 or less, and n 301 pieces of Ra 301 's and n 302 pieces of Ra 302 's are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, in Formula (A4), n 401 is an integer of 0 or greater and 6 or less, and n 401 pieces of Ra 401 's are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, in Formula (A5), n 501 , n 502 , and n 503 are each independently an integer of 0 or greater and 4 or less, and n 501 pieces of Ra 501 's, n 502 pieces of Ra 502 's, and n 503 pieces of Ra 503 's are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, in Formula (B), Ar B1 and Ar B2 are each independently an aromatic ring which may have a substituent, L B is a single bond, an oxygen atom, a sulfur atom, or -C(Rb 1 )(Rb 2 )-, and n B1 is 0, 1, or 2, where Rb 1 and Rb 2 are each independently a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, and Rb 1 and Rb 2 may be bonded to each other to form a cyclic alkyl group.

Inventors

OKAZAKI, YUTO
IDE, KENTA
NARITA, KOSUKE
SASAKI, TOMOYA
KUSANO, KEISUKE
FUJII, RYOSUKE
IWASAKI, MASAHIRO
KIGOSHI, YOICHI
KANO, FUYUKI
OYAMADA, YUKI
TAKAOKA, KOHEI

Assignees

FUJIFILM Business Innovation Corp.

Dates

Publication Date: 20260513
Application Date: 20250505

Claims (9)

An electrophotographic photoreceptor comprising: a conductive substrate; and a photosensitive layer disposed on the conductive substrate, wherein an outermost surface layer contains a charge transport material, a polyarylate resin having at least one dicarboxylic acid unit selected from the group consisting of a dicarboxylic acid unit (A2) represented by Formula (A2), a dicarboxylic acid unit (A3) represented by Formula (A3), a dicarboxylic acid unit (A4) represented by Formula (A4), and a dicarboxylic acid unit (A5) represented by Formula (A5) and a diol unit represented by Formula (B), and a polycarbonate resin, and a weight-average molecular weight MwA of the polyarylate resin and a weight-average molecular weight MwB of the polycarbonate resin satisfy -14 ≤ 100 × (MwA - MwB)/MwA ≤ 14, in Formula (A2), n 201 and n 202 are each independently an integer of 0 or greater and 4 or less, and n 201 pieces of Ra 201 's and n 202 pieces of Ra 202 's are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, in Formula (A3), n 301 and n 302 are each independently an integer of 0 or greater and 4 or less, and n 301 pieces of Ra 301 's and n 302 pieces of Ra 302 's are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, in Formula (A4), n 401 is an integer of 0 or greater and 6 or less, and n 401 pieces of Ra 401 's are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, in Formula (A5), n 501 , n 502 , and n 503 are each independently an integer of 0 or greater and 4 or less, and n 501 pieces of Ra 501 's, n 502 pieces of Ra 502 's, and n 503 pieces of Ra 503 's are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms, in Formula (B), Ar B1 and Ar B2 are each independently an aromatic ring which may have a substituent, L B is a single bond, an oxygen atom, a sulfur atom, or -C(Rb 1 )(Rb 2 )-, and n B1 is 0, 1, or 2, where Rb 1 and Rb 2 are each independently a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, and Rb 1 and Rb 2 may be bonded to each other to form a cyclic alkyl group.
The electrophotographic photoreceptor according to claim 1, wherein the weight-average molecular weight MwA of the polyarylate resin and the weight-average molecular weight MwB of the polycarbonate resin satisfy -8 ≤ 100 × (MwA - MwB)/MwA ≤ 8.
The electrophotographic photoreceptor according to claim 1 or 2, wherein the weight-average molecular weight MwA of the polyarylate resin is 70,000 or more and 140,000 or less.
The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein the diol unit represented by Formula (B) includes at least one selected from the group consisting of a diol unit (B 1) represented by Formula (B 1), a diol unit (B2) represented by Formula (B2), a diol unit (B3) represented by Formula (B3), a diol unit (B4) represented by Formula (B4), a diol unit (B5) represented by Formula (B5), a diol unit (B6) represented by Formula (B6), a diol unit (B7) represented by Formula (B7), and a diol unit (B8) represented by Formula (B8), in Formula (B 1), Rb 101 is a branched alkyl group having 4 or more and 20 or less carbon atoms, Rb 201 is a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms, and Rb 401 , Rb 501 , Rb 801 , and Rb 901 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom, in Formula (B2), Rb 102 is a linear alkyl group having 4 or more and 20 or less carbon atoms, Rb 202 is a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms, and Rb 402 , Rb 502 , Rb 802 , and Rb 902 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom, in Formula (B3), Rb 113 and Rb 213 are each independently a hydrogen atom, a linear alkyl group having 1 or more and 3 or less carbon atoms, an alkoxy group having 1 or more and 4 or less carbon atoms, or a halogen atom, d is an integer of 7 or greater and 15 or less, and Rb 403 , Rb 503 , Rb 803 , and Rb 903 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom, in Formula (B4), Rb 104 and Rb 204 are each independently a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms, and Rb 404 , Rb 504 , Rb 804 , and Rb 904 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom, in Formula (B5), Ar 105 is an aryl group having 6 or more and 12 or less carbon atoms or an aralkyl group having 7 or more and 20 or less carbon atoms, Rb 205 is a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms, and Rb 405 , Rb 505 , Rb 805 , and Rb 905 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom, in Formula (B6), Rb 116 and Rb 216 are each independently a hydrogen atom, a linear alkyl group having 1 or more and 3 or less carbon atoms, an alkoxy group having 1 or more and 4 or less carbon atoms, or a halogen atom, e is an integer of 4 or greater and 6 or less, and Rb 406 , Rb 506 , Rb 806 , and Rb 906 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom, in Formula (B7), Rb 407 , Rb 507 , Rb 807 , and Rb 907 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom, in Formula (B8), Rb 408 , Rb 508 , Rb 808 , and Rb 908 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom.
The electrophotographic photoreceptor according to any one of claims 1 to 4, wherein the polyarylate resin and the polycarbonate resin each have a constitutional unit including biphenyl represented by Formula (BP), in Formula (BP), j is an integer of 0 or greater and 4 or less, j pieces of R 1 's are each independently a methyl group or an ethyl group, k is an integer of 0 or greater and 4 or less, and k pieces of R 2 's are each independently a methyl group or an ethyl group.
The electrophotographic photoreceptor according to any one of claims 1 to 5, wherein a proportion of the polyarylate resin in a total amount of the polyarylate resin and the polycarbonate resin contained in the outermost surface layer is 25% by mass or more and 75% by mass or less.
The electrophotographic photoreceptor according to any one of claims 1 to 6, wherein the photosensitive layer includes a charge generation layer and a charge transport layer, and the charge transport layer is the outermost surface layer.
A process cartridge comprising: the electrophotographic photoreceptor according to any one of claims 1 to 7, wherein the process cartridge is attachable to and detachable from an image forming apparatus.
An image forming apparatus comprising: the electrophotographic photoreceptor according to any one of claims 1 to 7; a charging device that charges a surface of the electrophotographic photoreceptor; an electrostatic latent image forming device that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; and a transfer device that transfers the toner image to a surface of a recording medium.

Description

BACKGROUND OF THE INVENTION (i) Field of the Invention The present disclosure relates to an electrophotographic photoreceptor, a process cartridge, and an image forming apparatus. (ii) Description of Related Art JP2002-107965A discloses an electrophotographic photoreceptor in which a surface layer contains a polyarylate, a polycarbonate, a siloxane copolymerized polycarbonate, and a graft copolymer containing a polymerizable monomer having a silicon atom in a side chain as a constitutional component, where a viscosity average molecular weight (Ma) of the polyarylate is 30,000 or more and 105,000 or less, a viscosity average molecular weight (Mc) of the polycarbonate is 25,000 or more and 55,000 or less, and Ma > Mc. JP2023-121553A discloses a photoreceptor in which a charge transport layer contains at least one of a polyester resin having a constitutional unit having an aromatic ring or a polycarbonate resin having a constitutional unit having an aromatic ring. JP2024-011918A discloses an electrophotographic photoreceptor in which a charge transport layer contains a charge transport material, a polyester resin having a predetermined aromatic structure, and a polycarbonate resin. SUMMARY OF THE INVENTION An object of the present disclosure is to provide an electrophotographic photoreceptor in which cleaning properties are maintained until the end of the life and an outermost surface layer is less likely to be peeled off. Specific methods for achieving the above-described object include the following aspects. Each formula is the same as the formula having the same number described later. <1> According to a first aspect of the present disclosure, there is provided an electrophotographic photoreceptor including a conductive substrate, and a photosensitive layer disposed on the conductive substrate, in which an outermost surface layer contains a charge transport material, a polyarylate resin having at least one dicarboxylic acid unit selected from the group consisting of a dicarboxylic acid unit (A2) represented by Formula (A2), a dicarboxylic acid unit (A3) represented by Formula (A3), a dicarboxylic acid unit (A4) represented by Formula (A4), and a dicarboxylic acid unit (A5) represented by Formula (A5) and a diol unit represented by Formula (B), and a polycarbonate resin, and a weight-average molecular weight MwA of the polyarylate resin and a weight-average molecular weight MwB of the polycarbonate resin satisfy -14 ≤ 100 × (MwA - MwB)/MwA ≤ 14.<2> According to a second aspect of the present disclosure, there is provided the electrophotographic photoreceptor according to <1>, in which the weight-average molecular weight MwA of the polyarylate resin and the weight-average molecular weight MwB of the polycarbonate resin may satisfy -8 ≤ 100 × (MwA - MwB)/MwA ≤ 8.<3> According to a third aspect of the present disclosure, there is provided the electrophotographic photoreceptor according to <1> or <2>, in which the weight-average molecular weight MwA of the polyarylate resin may be 70,000 or more and 140,000 or less.<4> According to a fourth aspect of the present disclosure, there is provided the electrophotographic photoreceptor according to any one of <1> to <3>, in which the diol unit represented by Formula (B) may include at least one selected from the group consisting of a diol unit (B1) represented by Formula (B1), a diol unit (B2) represented by Formula (B2), a diol unit (B3) represented by Formula (B3), a diol unit (B4) represented by Formula (B4), a diol unit (B5) represented by Formula (B5), a diol unit (B6) represented by Formula (B6), a diol unit (B7) represented by Formula (B7), and a diol unit (B8) represented by Formula (B8).<5> According to a fifth aspect of the present disclosure, there is provided the electrophotographic photoreceptor according to any one of <1> to <4>, in which the polyarylate resin and the polycarbonate resin each may have a constitutional unit including biphenyl represented by Formula (BP).<6> According to a sixth aspect of the present disclosure, there is provided the electrophotographic photoreceptor according to any one of <1> to <5>, in which a proportion of the polyarylate resin in a total amount of the polyarylate resin and the polycarbonate resin contained in the outermost surface layer may be 25% by mass or more and 75% by mass or less.<7> According to a seventh aspect of the present disclosure, there is provided the electrophotographic photoreceptor according to any one of <1> to <6>, in which the photosensitive layer may include a charge generation layer and a charge transport layer, and the charge transport layer may be the outermost surface layer.<8> According to an eighth aspect of the present disclosure, there is provided a process cartridge including the electrophotographic photoreceptor according to any one of <1> to <7>, in which the process cartridge may be attachable to and detachable from an image forming apparatus.<9> According to a ninth aspect of the pr