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EP-4741935-A1 - IMAGE FORMING APPARATUS

EP4741935A1EP 4741935 A1EP4741935 A1EP 4741935A1EP-4741935-A1

Abstract

An image forming apparatus includes an electrophotographic photoreceptor, and a charging device including a charging member that charges a surface of the electrophotographic photoreceptor and a cleaning member that is disposed in contact with the charging member, in which the electrophotographic photoreceptor has a conductive substrate and a photosensitive layer disposed on the conductive substrate, and an outermost surface layer of the electrophotographic photoreceptor contains a charge transport material and a polyarylate resin having a dicarboxylic acid unit represented by Formula (A) and a diol unit represented by Formula (B), the cleaning member has a core metal and a foamed elastic layer provided in a helical shape on an outer peripheral surface of the core metal, and a value of a ratio T/W of a thickness T of the foamed elastic layer to a width W of the foamed elastic layer is 0.6 or more and 1.2 or less, in Formula (A), Ar A1 and Ar A2 are each independently an aromatic ring which may have a substituent, L A is a single bond or a divalent linking group, and n A1 is 0, 1, or 2, in Formula (B), Ar B1 and Ar B2 are each independently an aromatic ring which may have a substituent, L B is a single bond, 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

  • KANO, FUYUKI
  • KIGOSHI, YOICHI
  • OYAMADA, YUKI
  • TAKAOKA, KOHEI
  • KUSANO, KEISUKE
  • SASAKI, TOMOYA
  • IDE, KENTA

Assignees

  • FUJIFILM Business Innovation Corp.

Dates

Publication Date
20260513
Application Date
20250502

Claims (8)

  1. An image forming apparatus comprising: an electrophotographic photoreceptor; and a charging device including a charging member that charges a surface of the electrophotographic photoreceptor and a cleaning member that is disposed in contact with the charging member, wherein the electrophotographic photoreceptor has a conductive substrate and a photosensitive layer disposed on the conductive substrate, and an outermost surface layer of the electrophotographic photoreceptor contains a charge transport material and a polyarylate resin having a dicarboxylic acid unit represented by Formula (A) and a diol unit represented by Formula (B), the cleaning member has a core metal and a foamed elastic layer provided in a helical shape on an outer peripheral surface of the core metal, and a value of a ratio T/W of a thickness T of the foamed elastic layer to a width W of the foamed elastic layer is 0.6 or more and 1.2 or less, in Formula (A), Ar A1 and Ar A2 are each independently an aromatic ring which may have a substituent, L A is a single bond or a divalent linking group, and n A1 is 0, 1, or 2, in Formula (B), Ar B1 and Ar B2 are each independently an aromatic ring which may have a substituent, L B is a single bond, 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.
  2. The image forming apparatus according to claim 1, wherein a coverage area ratio A of the foamed elastic layer provided in the cleaning member is 20% by area or more and 60% by area or less.
  3. The image forming apparatus according to claim 1 or 2, wherein a surface roughness Rz of the charging member is 5 µm or more and 10 µm or less.
  4. The image forming apparatus according to any one of claims 1 to 3, wherein the outermost surface layer of the electrophotographic photoreceptor further contains a polycarbonate resin.
  5. The image forming apparatus according to claim 4, wherein a mass ratio of the polyarylate resin to the polycarbonate resin in the outermost surface layer of the electrophotographic photoreceptor is 3:7 to 7:3.
  6. The image forming apparatus according to any one of claims 1 to 5, wherein the dicarboxylic acid unit represented by Formula (A) includes at least one selected from the group consisting of a dicarboxylic acid unit (A1) represented by Formula (A1), a dicarboxylic acid unit (A2) represented by Formula (A2), a dicarboxylic acid unit (A3) represented by Formula (A3), a dicarboxylic acid unit (A4) represented Formula (A4), and a dicarboxylic acid unit (A5) represented by Formula (A5), in Formula (A1), n 101 is an integer of 0 or greater and 4 or less, and n 101 pieces of Ra 101 '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 (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 (AS), 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 501 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.
  7. The image forming apparatus according to any one of claims 1 to 6, 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.
  8. The image forming apparatus according to claim 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.

Description

BACKGROUND OF THE INVENTION (i) Field of the Invention The present invention relates to an image forming apparatus. (ii) Description of Related Art JP2005-309039A discloses an image forming apparatus in which a latent image carrier is charged using a charging member that comes into contact with the latent image carrier and is rotationally driven, the charged latent image carrier is exposed to form an electrostatic latent image, the electrostatic latent image is developed using toner carried by a toner carrying body to form a toner image, the toner image formed on the latent image carrier is transferred onto a transfer material using a transfer member that abuts onto the latent image carrier and is rotated, a transfer residual toner remaining on the latent image carrier after the transfer is collected by a cleaning unit, the toner image on the transfer material after the transfer is fixed to the transfer material by a fixing unit, the charging member has a material having high release properties on a surface, and the transfer member is formed of a foaming body and has a skin layer on a surface. JP2012-78518A discloses a charging device including a charging member, and a cleaning member having a core body and an elastic layer that contains silicone oil and is disposed in a helical shape on an outer peripheral surface of the core body, in which after the elastic layer of the cleaning member in an initial state and the charging member in the initial state are brought into contact with each other for 24 hours, among contents of Si atoms constituting a siloxane skeleton with respect to all atoms, which are obtained by analyzing a surface of the charging member by X-ray photoelectron spectroscopy, a maximum value of a content of Si atoms constituting the siloxane skeleton in a contact portion, which is a region in contact with the elastic layer, and a content of Si atoms constituting the siloxane skeleton in a non-contact portion, which is a region not in contact with the elastic layer, is 6 atom% or less. JP2014-146001A discloses a positively charged lamination-type electrophotographic photoreceptor in which a lamination-type photosensitive layer where a charge transport layer consisting of at least a hole transport material and a binder resin and a charge generation/transport layer consisting of at least a charge generation material, an electron transport material, a hole transport material, and a binder resin are sequentially laminated on a conductive substrate is formed, the binder resin in the charge transport layer contains a polyarylate resin, a thickness of the charge transport layer is 10 to 40 µm, and a thickness of the charge generation/transport layer is 3 to 20 µm. SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which an outermost surface layer of an electrophotographic photoreceptor does not contain a charge transport material and a polyarylate resin having a dicarboxylic acid unit represented by Formula (A) and a diol unit represented by Formula (B), or a cleaning member has a core metal and a foamed elastic layer provided in a helical shape on an outer peripheral surface of the core metal, and in which abrasion-suppressing properties of a photoreceptor and contamination-suppressing properties of a charging member are excellent as compared with a case where a value of a ratio T/W of a thickness T of the foamed elastic layer to a width W of the foamed elastic layer is less than 0.6 or more than 1.2. Methods for achieving the above-described object include the following aspects. <1> According to a first aspect of the present disclosure, there is provided an image forming apparatus including an electrophotographic photoreceptor, and a charging device including a charging member that charges a surface of the electrophotographic photoreceptor and a cleaning member that is disposed in contact with the charging member, in which the electrophotographic photoreceptor has a conductive substrate and a photosensitive layer disposed on the conductive substrate, and an outermost surface layer of the electrophotographic photoreceptor contains a charge transport material and a polyarylate resin having a dicarboxylic acid unit represented by Formula (A) and a diol unit represented by Formula (B), the cleaning member has a core metal and a foamed elastic layer provided in a helical shape on an outer peripheral surface of the core metal, and a value of a ratio T/W of a thickness T of the foamed elastic layer to a width W of the foamed elastic layer is 0.6 or more and 1.2 or less. In Formula (A), ArA1 and ArA2 are each independently an aromatic ring which may have a substituent, LA is a single bond or a divalent linking group, and nA1 is 0, 1, or 2. In Formula (B), ArB1 and ArB2 are each independently an aromatic ring which may have a substituent, LB is a single bond, an oxygen atom, a sulfur atom, or -C(Rb1)(Rb2)-, and nB1 is 0, 1, or 2. Where Rb1 and Rb2 are e