CN-122018261-A - Electrophotographic photoreceptor, process cartridge, and image forming apparatus

CN122018261ACN 122018261 ACN122018261 ACN 122018261ACN-122018261-A

Abstract

An electrophotographic photoreceptor, a process cartridge, and an image forming apparatus, the electrophotographic photoreceptor including a conductive substrate, an undercoat layer disposed on the conductive substrate, and a laminated photosensitive layer disposed on the undercoat layer and having a charge generation layer and a charge transport layer, the charge transport layer containing a charge transport material and a polyarylate resin, the polyarylate resin including a dicarboxylic acid unit represented by the following formula (A) and a diol unit represented by the following formula (B), the undercoat layer having an electrostatic capacity of 1.0X10 ‑10 F to 3.0X10 ‑9 F. [ chemical formula 1] formula (A) Equation (B)

Inventors

OYAMADA YUKI
SASAKI TOMOYA
Kiko Youchi
KANO FUYUKI
IWASAKI MASAHIRO
Kusano Kawoo
FUJII RYOUSUKE
Okazaki Youdu
GAO YANGPING
IDE KENTA

Assignees

富士胶片商业创新有限公司

Dates

Publication Date: 20260512
Application Date: 20250430
Priority Date: 20241111

Claims (10)

1. An electrophotographic photoreceptor comprising: A conductive substrate; a lower coating layer disposed on the conductive substrate, and A laminated photosensitive layer disposed on the undercoating layer and having a charge generating layer and a charge transporting layer, The charge transport layer contains a charge transport material and a polyarylate resin, The polyarylate resin comprises a dicarboxylic acid unit represented by the following formula (A) and a diol unit represented by the following formula (B), The electrostatic capacity of the lower coating layer is 1.0X10 -10 F or more and 3.0X10 -9 F or less, [ Chemical formula 1] In the 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 2-valent linking group, and n A1 is 0, 1 or 2; In the 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 )-,n B1 is 0, 1 or 2; rb 1 and Rb 2 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, or Rb 1 and Rb 2 may be bonded to form a cyclic alkyl group.
2. The electrophotographic photoreceptor according to claim 1, wherein, The relative dielectric constant of the charge transport layer is 3.0 or more and 5.0 or less.
3. The electrophotographic photoreceptor according to claim 1 or 2, wherein, The ratio of the relative permittivity of the charge transport layer to the relative permittivity of the undercoating layer, that is, the relative permittivity of the charge transport layer/the relative permittivity of the undercoating layer is 0.010 or more and 0.400 or less.
4. The electrophotographic photoreceptor according to any of claim 1 to 3, wherein, The under-coating layer contains zinc oxide particles to which an electron-accepting compound is added, and the zinc oxide particles are present at 62 mass% or more and 75 mass% or less relative to the under-coating layer.
5. The electrophotographic photoreceptor according to claim 4, wherein, The electron-accepting compound is an anthraquinone derivative having 3 OH groups or 2 OH groups and having 1 alkoxy group.
6. The electrophotographic photoreceptor according to claim 5, wherein, The anthraquinone derivative is alizarin derivative represented by a formula (C), [ Chemical formula 2] In the formula (C), R represents a hydroxyl group or an alkoxy group having 1 to 10 carbon atoms.
7. The electrophotographic photoreceptor according to any of claims 1 to 6, wherein, The film thickness of the undercoating layer is 17 [ mu ] m or more and 35 [ mu ] m or less.
8. The electrophotographic photoreceptor according to any of claims 1 to 7, wherein, The charge transport layer further comprises a polycarbonate resin, The polyarylate resin and the polycarbonate resin each have a structural unit comprising biphenyl represented by the following formula (BP), [ Chemical formula 3] In the formula (BP), j is an integer of 0 to 4, j R 1 are each independently methyl or ethyl, k is an integer of 0 to 4, and k R 2 are each independently methyl or ethyl.
9. A process cartridge provided with the electrophotographic photoreceptor as claimed in any one of claim 1 to 8, The process cartridge is attached to and detached from the image forming apparatus.
10. An image forming apparatus includes: the electrophotographic photoreceptor of any one of claims 1 to 8; A charging unit that charges a surface of the electrophotographic photoreceptor; An electrostatic latent image forming unit that forms an electrostatic latent image on the charged electrophotographic photoreceptor surface; a developing unit for developing an electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image, and And a transfer unit for transferring the toner image onto the surface of the recording medium.

Description

Electrophotographic photoreceptor, process cartridge, and image forming apparatus Technical Field The invention relates to an electrophotographic photoreceptor, a process cartridge, and an image forming apparatus. Background Patent document 1 discloses an electrophotographic photoreceptor which includes a support, an undercoat layer provided on the support and containing at least a binder resin, metal oxide particles, and an electron-accepting compound having an anthraquinone structure, wherein the content of the electron-accepting compound relative to the metal oxide particles is 0.5 mass% or more and 1.5 mass% or less, and the contact angle of the metal oxide particles relative to water is 7 degrees or more and 12 degrees or less, and a photosensitive layer provided on the undercoat layer. Patent document 2 discloses an electrophotographic photoreceptor which includes a conductive substrate, an undercoat layer provided on the conductive substrate and containing a binder resin, metal oxide particles, and an electron-accepting compound having an anthraquinone skeleton represented by the following general formula (1A), wherein the reflectance RL of light in a wavelength range of 470nm to 510nm is 2% to 5%, and a photosensitive layer provided on the undercoat layer. Patent document 3 discloses an electrophotographic photoreceptor including a conductive substrate, a lower coating layer provided on the conductive substrate, a charge generation layer provided on the lower coating layer, a charge transport layer provided on the charge generation layer, and a protective layer provided on the charge transport layer, wherein the lower coating layer includes a conductive agent, the total of the number of primary particles of the conductive agent and the number of secondary particles of the conductive agent is 58% or less, and the charge mobility μ (CTL) of the charge transport layer and the charge mobility μ (OCL) of the protective layer satisfy μ (CTL) 1.0×10 -5(cm2/Vs) and μ (OCL) 0.68×10 -5(cm2/Vs. Patent document 1 Japanese patent application laid-open No. 2013-242483 Patent document 2 Japanese patent No. 6838324 Patent document 3 Japanese patent laid-open No. 2024-043372 Disclosure of Invention The object of the present invention is to provide an electrophotographic photoreceptor in which potential fluctuation after formation of an electrostatic latent image is suppressed, as compared with the case where the electrophotographic photoreceptor includes a conductive substrate, an undercoat layer disposed on the conductive substrate, and a laminated photosensitive layer disposed on the undercoat layer and having a charge generating layer and a charge transporting layer, the charge transporting layer containing a charge transporting material and a polyarylate resin containing a dicarboxylic acid unit represented by the above formula (A) and a diol unit represented by the above formula (B), the electrostatic capacity of the undercoat layer is less than 1.0X10 -10 F or exceeds 3.0X10 -9 F. Specific means for solving the above problems include the following means. <1> An electrophotographic photoreceptor comprising: A conductive substrate; a lower coating layer disposed on the conductive substrate, and A laminated photosensitive layer disposed on the undercoating layer and having a charge generating layer and a charge transporting layer, The charge transport layer contains a charge transport material and a polyarylate resin, The polyarylate resin comprises a dicarboxylic acid unit represented by the following formula (A) and a diol unit represented by the following formula (B), The electrostatic capacity of the lower coating layer is 1.0X10 -10 F or more and 3.0X10 -9 F or less, [ Chemical formula 1] In the 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 2-valent linking group, and n A1 is 0, 1 or 2; In the 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)(Rb2)-,nB1 is 0, 1 or 2; rb 1 and Rb 2 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, or Rb 1 and Rb 2 may be bonded to form a cyclic alkyl group. <2> The electrophotographic photoreceptor according to <1>, wherein, The relative dielectric constant of the charge transport layer is 3.0 or more and 5.0 or less. <3> The electrophotographic photoreceptor according to <1> or <2>, wherein, The ratio of the relative permittivity of the charge transport layer to the relative permittivity of the undercoating layer, that is, the relative permittivity of the charge transport layer/the relative permittivity of the undercoating layer is 0.010 or more and 0.400 or less. <4> The electrophotographic photoreceptor according to any of <1> to <3>, wherein, The under-coating l