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EP-4462190-B1 - ELECTROPHOTOGRAPHIC PHOTOSENSITIVE MEMBER, PROCESS CARTRIDGE, AND ELECTROPHOTOGRAPHIC APPARATUS

EP4462190B1EP 4462190 B1EP4462190 B1EP 4462190B1EP-4462190-B1

Inventors

  • SEKIYA, MICHIYO
  • MARUYAMA, AKIHIRO
  • NISHI, MASASHI
  • KATO, Nanami

Dates

Publication Date
20260506
Application Date
20240326

Claims (9)

  1. An electrophotographic photosensitive member comprising in this order: a support; an electron-transporting layer; a charge-generating layer; and a hole-transporting layer, wherein the electron-transporting layer comprises a polymer having a structural unit represented by the following formula (1), the following formula (2), or the following formula (3), and wherein the polymer has a glass transition temperature Tg measured according to the method disclosed in the description of -10 to 50°C: in the formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , and R 18 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thiol group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aryl group, R 61 represents a hydrogen atom, or a substituted or unsubstituted alkyl group, and m 1 represents an integer of 2 to 16; in the formula (2), R 22 , R 23 , R 24 , R 26 , R 27 , and R 28 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thiol group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aryl group, R 62 represents a hydrogen atom, or a substituted or unsubstituted alkyl group, R 41 and R 42 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and m 2 represents an integer of 2 to 16; and in the formula (3), R 31 , R 33 , R 34 , R 35 , R 37 , and R 38 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thiol group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aryl group, R 63 represents a hydrogen atom, or a substituted or unsubstituted alkyl group, R 51 and R 52 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and m 3 represents an integer of 2 to 16.
  2. The electrophotographic photosensitive member according to claim 1, wherein m 1 in the formula (1), m 2 in the formula (2), and m 3 in the formula (3) each represent an integer of 2 to 6.
  3. The electrophotographic photosensitive member according to claim 1 or 2, wherein R 61 in the formula (1), R 62 in the formula (2), and R 63 in the formula (3) each represent a methyl group.
  4. The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the polymer has a weight-average molecular weight measured according to the method disclosed in the description of 30,000 or less.
  5. The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein a CuKα characteristic X-ray diffraction pattern obtained for the electron-transporting layer has a peak at a position of 2θ=7.5°±2.5° where θ represents a Bragg angle.
  6. A method of producing an electrophotographic photosensitive member comprising a support, an electron-transporting layer, a charge-generating layer, and a hole-transporting layer in the stated order, the method comprising a step of forming a coating film of a coating liquid for an electron-transporting layer, followed by drying and/or curing of the coating film to form the electron-transporting layer, wherein the coating liquid for an electron-transporting layer comprises a polymer having a structural unit represented by the following formula (1), the following formula (2), or the following formula (3), and wherein the polymer has a glass transition temperature Tg measured according to the method disclosed in the description of -10 to 50°C in the formula (1), R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , and R 18 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thiol group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aryl group, R 61 represents a hydrogen atom, or a substituted or unsubstituted alkyl group, and m 1 represents an integer of 2 to 16; in the formula (2), R 22 , R 23 , R 24 , R 26 , R 27 , and R 28 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thiol group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aryl group, R 62 represents a hydrogen atom, or a substituted or unsubstituted alkyl group, R 41 and R 42 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and m 2 represents an integer of 2 to 16; and in the formula (3), R 31 , R 33 , R 34 , R 35 , R 37 , and R 38 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thiol group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aryl group, R 63 represents a hydrogen atom, or a substituted or unsubstituted alkyl group, R 51 and R 52 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and m 3 represents an integer of 2 to 16.
  7. The method of producing an electrophotographic photosensitive member according to claim 6, wherein the coating liquid for an electron-transporting layer further comprises a crosslinking agent, and wherein the step includes curing the coating film.
  8. A process cartridge comprising: the electrophotographic photosensitive member of any one of claims 1 to 5; and at least one unit selected from the group consisting of: a charging unit; a developing unit; and a cleaning unit, the process cartridge integrally supporting the electrophotographic photosensitive member and the at least one unit, and being detachably attachable to a main body of an electrophotographic apparatus.
  9. An electrophotographic apparatus comprising: the electrophotographic photosensitive member of any one of claims 1 to 5; a charging unit; an exposing unit; a developing unit; and a transfer unit.

Description

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photosensitive member, and a process cartridge and an electrophotographic apparatus each including the electrophotographic photosensitive member. Description of the Related Art In an electrophotographic photosensitive member to be used for an electrophotographic process, there is known a technology involving arranging an undercoat layer containing an electron-transporting substance between a support and a photosensitive layer for the purpose of suppressing charge injection from the support side to the photosensitive layer side to suppress the occurrence of an image failure such as a black spot. In Japanese Patent Application Laid-Open No. 2010-198014, there is a description of an electron-transporting layer containing a copolymer having a repeating unit including a structure having electron transportability. In addition, in Japanese Patent Application Laid-Open No. 2003-345044, there is a description of a resin having a repeating unit including a structure having electron transportability. In recent years, the electrophotographic process has been required to achieve mass printing and high-speed printing. Through an investigation made by the inventors of the present invention, it has been found that in an electrophotographic photosensitive member described in each of Japanese Patent Application Laid-Open No. 2010-198014 and Japanese Patent Application Laid-Open No. 2003-345044, when the mass printing and the high-speed printing are performed, an image failure called a pattern memory and an image failure called a ghost may occur. WO 2007/024522 discloses an electrophotographic photosensitive member comprising in this order a support, an electron-transporting layer; and a photosensitive layer, wherein the electron-transporting layer comprises a polymer having a perylene imide structure. The pattern memory is such a phenomenon as described below. For example, an image 301 including vertical lines 306 illustrated in FIG. 1A is continuously output in a large number, and then a solid black image 302 illustrated in FIG. 1B is output. At this time, in the phenomenon, the output solid black image causes an image 304 including such vertical lines 307 as illustrated in FIG. 1C, the lines resulting from the fact that the vertical lines 306 in the image 301 illustrated in FIG. 1A have been repeatedly recorded. In addition, for example, the image 301 illustrated in FIG. 1A is continuously output in a large number, and then a halftone image 303 illustrated in FIG. 1D is output. In this case, in the phenomenon, as in the case where the solid black image 302 illustrated in FIG. 1B is output, an image 305 including vertical lines 308 illustrated in FIG. 1E, the lines resulting from the fact that the vertical lines 306 in the image 301 illustrated in FIG. 1A have been repeatedly recorded, occurs. In addition, the ghost is such a phenomenon as described below. For example, such an image as illustrated in FIG. 2A including black backgrounds (black images) 52 in a white background (white image) 51 in its front portion, followed by a halftone image 53 of a one-dot keima (knight of Japanese chess) pattern illustrated in FIG. 2B, is output. At this time, in the phenomenon, such portions as indicated by ghost portions 54, the portions each having an image density different from that of its surroundings, occur in the halftone image 53 of the image illustrated in FIG. 2A. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electrophotographic photosensitive member that can suppress the occurrence of a pattern memory and a ghost, a method of producing the electrophotographic photosensitive member, a process cartridge including the electrophotographic photosensitive member, and an electrophotographic apparatus including the electrophotographic photosensitive member. The above-mentioned object is achieved by the present invention described below. That is, according to the present invention, there is provided an electrophotographic photosensitive member including in this order: a support; an electron-transporting layer; a charge-generating layer; and a hole-transporting layer, wherein the electron-transporting layer comprises a polymer having a structural unit represented by the following formula (1), the following formula (2), or the following formula (3), and wherein the polymer has a glass transition temperature Tg of -10 to 50°C: in the formula (1), R11, R12, R13, R14, R15, R16, R17, and R18 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thiol group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aryl group, R61 represents a hyd