Search

EP-4741932-A1 - ELECTROPHOTOGRAPHIC PHOTORECEPTOR, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS

EP4741932A1EP 4741932 A1EP4741932 A1EP 4741932A1EP-4741932-A1

Abstract

An electrophotographic photoreceptor includes a conductive substrate, a charge generation layer disposed on the conductive substrate, and a charge transport layer disposed on the charge generation layer, in which the charge transport layer contains a phenolic compound, a polyarylate resin, a polycarbonate resin, and a charge transport material, and each of a vector distance DIS HT (J/cm 3 ) 1/2 between an HSP value of the charge transport material and an HSP value of the polyarylate resin, and a vector distance DIS PC (J/cm 3 ) 1/2 between the HSP value of the polycarbonate resin and the HSP value of the polyarylate resin, which are calculated based on a Hansen solubility parameter, satisfies Expression (1) and Expression (2), DIS HT ≤ 3.9 , 9.2 ≤ DIS PC < 12.0 .

Inventors

  • IWASAKI, MASAHIRO
  • SASAKI, TOMOYA
  • IDE, KENTA
  • KIGOSHI, YOICHI
  • KANO, FUYUKI
  • OYAMADA, YUKI
  • TAKAOKA, KOHEI
  • NARITA, KOSUKE

Assignees

  • FUJIFILM Business Innovation Corp.

Dates

Publication Date
20260513
Application Date
20251006

Claims (13)

  1. An electrophotographic photoreceptor comprising: a conductive substrate; a charge generation layer disposed on the conductive substrate; and a charge transport layer disposed on the charge generation layer, wherein the charge transport layer contains a phenolic compound, a polyarylate resin, a polycarbonate resin, and a charge transport material, and each of a vector distance DIS HT (J/cm 3 ) 1/2 between an HSP value of the charge transport material and an HSP value of the polyarylate resin, and a vector distance DIS PC (J/cm 3 ) 1/2 between the HSP value of the polycarbonate resin and the HSP value of the polyarylate resin, which are calculated based on a Hansen solubility parameter, satisfies Expression (1) and Expression (2), DIS HT ≤ 3.9 , 9.2 ≤ DIS PC < 12.0 .
  2. The electrophotographic photoreceptor according to claim 1, wherein a vector distance DIS OHCT (J/cm 3 ) 1/2 between an HSP value of the phenolic compound and the HSP value of the charge transport material, which are calculated based on a Hansen solubility parameter, satisfies Expression (3), 3.6 ≤ DIS OHCT ≤ 7.0 .
  3. The electrophotographic photoreceptor according to claim 1 or 2, wherein a vector distance DIS OHPA (J/cm 3 ) 1/2 between an HSP value of the phenolic compound and the HSP value of the polyarylate resin, which are calculated based on a Hansen solubility parameter, satisfies Expression (4), 5.5 ≤ DIS OHPA ≤ 8.0 .
  4. The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein a hydrogen bonding term δH OH (J/cm 3 ) 1/2 of the phenolic compound, which is calculated based on a Hansen solubility parameter, satisfies Expression (5), 3.5 ≤ δH OH ≤ 7.7 .
  5. The electrophotographic photoreceptor according to any one of claims 1 to 4, wherein the phenolic compound includes a hindered phenolic compound.
  6. The electrophotographic photoreceptor according to claim 5, wherein the phenolic compound includes a phenolic compound having 3 or fewer phenolic functional groups and a molecular weight of 300 or more.
  7. The electrophotographic photoreceptor according to any one of claims 1 to 6, wherein the polyarylate resin has a dicarboxylic acid unit represented by Formula (A) and a diol unit represented by Formula (B), 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.
  8. The electrophotographic photoreceptor according to any one of claims 1 to 7, 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.
  9. A process cartridge comprising: the electrophotographic photoreceptor according to any one of claims 1 to 8, wherein the process cartridge is attachable to and detachable from an image forming apparatus.
  10. An image forming apparatus comprising: the electrophotographic photoreceptor according to any one of claims 1 to 8; 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.
  11. The image forming apparatus according to claim 10, further comprising: a cleaning device that has a cleaning blade coming into contact with the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor.
  12. The image forming apparatus according to claim 11, wherein a contact portion of the cleaning blade coming into contact with the electrophotographic photoreceptor contains a polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component, and the contact portion is formed of a member having a ratio M100/Re of a 100% modulus M100 (MPa) to a rebound resilience Re (%) of 0.25 or more, the rebound resilience Re of less than 25%, and a tensile stress at a 200% strain of 15 MPa or more.
  13. The image forming apparatus according to claim 12, wherein the ratio M100/Re is 0.28 or more and 1.0 or less.

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 JP2024-011918A discloses an organic electrophotographic photoreceptor including a conductive substrate and a lamination-type photosensitive layer that is disposed on the conductive substrate and that includes a charge generation layer and a charge transport layer, in which the charge transport layer contains a charge transport material, a polyester resin having a specific structural unit, and a polycarbonate resin. JP2017-211448A discloses an electrophotographic photoreceptor including a conductive substrate and a photosensitive layer, in which the photosensitive layer contains at least a charge generation agent, a charge transport agent, and a binder resin, the binder resin includes a polyarylate resin and a polycarbonate resin, the polyarylate resin and the polycarbonate resin have a specific structural unit, and a ratio (mPAR/(mPAR + mPC)) of a content mPAR of the polyarylate resin to a total amount of the content mPAR of the polyarylate resin and a content mPC of the polycarbonate resin is 0.10 or more and 0.90 or less. SUMMARY OF THE INVENTION An object of the present exemplary embodiment is to provide an electrophotographic photoreceptor including a conductive substrate, a charge generation layer, and a charge transport layer including a charge transport material, a polyarylate resin, and a polycarbonate resin, in which image density unevenness is reduced as compared with "a case where the charge transport layer does not contain a phenolic compound" or "a case where the charge transport layer does not satisfy Expression (1) or (2)". 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, a charge generation layer disposed on the conductive substrate, and a charge transport layer disposed on the charge generation layer, in which the charge transport layer contains a phenolic compound, a polyarylate resin, a polycarbonate resin, and a charge transport material, and each of a vector distance DISHT (J/cm3)1/2 between an HSP value of the charge transport material and an HSP value of the polyarylate resin, and a vector distance DISPC (J/cm3)1/2 between the HSP value of the polycarbonate resin and the HSP value of the polyarylate resin, which are calculated based on a Hansen solubility parameter, satisfies Expression (1) and Expression (2), DISHT≤3.9, 9.2≤DISPC<12.0.<2> According to a second aspect of the present disclosure, there is provided the electrophotographic photoreceptor according to <1>, in which a vector distance DISOHCT (J/cm3)1/2 between an HSP value of the phenolic compound and the HSP value of the charge transport material, which are calculated based on a Hansen solubility parameter, may satisfy Expression (3), 3.6≤DISOHCT≤7.0.<3> According to a third aspect of the present disclosure, there is provided the electrophotographic photoreceptor according to <1> or <2>, in which a vector distance DISOHPA (J/cm3)1/2 between an HSP value of the phenolic compound and the HSP value of the polyarylate resin, which are calculated based on a Hansen solubility parameter, may satisfy Expression (4), 5.5≤DISOHPA≤8.0.<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 a hydrogen bonding term δHOH (J/cm3)1/2 of the phenolic compound, which is calculated based on a Hansen solubility parameter, may satisfy Expression (5), 3.5≤δHOH≤7.7.<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 phenolic compound may include a hindered phenolic compound.<6> According to a sixth aspect of the present disclosure, there is provided the electrophotographic photoreceptor according to <5>, in which the phenolic compound may include a phenolic compound having 3 or fewer phenolic functional groups and a molecular weight of 300 or more.<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 polyarylate resin may have a dicarboxylic acid unit represented by Formula (A) and a diol unit represented by Formula (B), 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)(Rb