US-12619171-B2 - Electrophotographic photosensitive member, process cartridge and electrophotographic apparatus

US12619171B2US 12619171 B2US12619171 B2US 12619171B2US-12619171-B2

Abstract

An electrophotographic photosensitive member including: a support, a charge generating layer, and a charge transporting layer in this order, wherein the charge transporting layer contains: a compound represented by the formula (A-1), and at least one selected from the group consisting of a compound represented by the formula (A-2) and a compound represented by the formula (A-3).

Inventors

Tatsuya Ohsawa
Kunihiko Sekido
Shuhei Iwasaki
Naoyuki Matsumoto

Assignees

CANON KABUSHIKI KAISHA

Dates

Publication Date: 20260505
Application Date: 20230908
Priority Date: 20220921

Claims (8)

1 . An electrophotographic photosensitive member comprising: a support, a charge generating layer, and a charge transporting layer in this order, wherein the charge transporting layer comprises: a compound represented by a following formula (A-1), and at least one selected from the group consisting of a compound represented by a following formula (A-2) and a compound represented by a following formula (A-3),
2 . The electrophotographic photosensitive member according to claim 1 , wherein, in the charge transporting layer, a sum of a content “A2” of the compound represented by the formula (A-2) and a content “A3” of the compound represented by the formula (A-3) satisfies a following relationship (1), the content “A2” of the compound represented by the formula (A-2) satisfies a following relationship (2), and the content “A3” of the compound represented by the formula (A-3) satisfies a following relationship (3), 0.019 mass %≤ A 2+ A 3≤0.129 mass % (1) 0.019 mass %≤ A 2≤0.070 mass % (2) 0 mass %≤ A 3≤0.058 mass % (3).
3 . The electrophotographic photosensitive member according to claim 1 , wherein the charge transporting layer further comprises a binder resin, and a content of the compound represented by the formula (A-1) with respect to a content of the binder resin is 60 to 100 mass % in the charge transporting layer.
4 . The electrophotographic photosensitive member according to claim 1 , wherein a content of a compound represented by a following formula (C-1) with respect to a content of the compound represented by the formula (A-1) is 43 mass % or less in the charge transporting layer, and a content of a compound represented by a following formula (C-2) with respect to the content of the compound represented by the formula (A-1) is 43 mass % or less in the charge transporting layer,
5 . The electrophotographic photosensitive member according to claim 1 , wherein a sum of a content of the compound represented by the formula (A-2), a content of the compound represented by the formula (A-3), a content of a compound represented by a following formula (C-1) and a content of a compound represented by a following formula (C-2) with respect to a content of the compound represented by the formula (A-1) is 43 mass % or less in the charge transporting layer,
6 . The electrophotographic photosensitive member according to claim 1 , wherein the charge generating layer comprises hydroxy phthalocyanine.
7 . A process cartridge comprising: an electrophotographic photosensitive member 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, wherein the electrophotographic photosensitive member comprises: a support, a charge generating layer, and a charge transporting layer in this order, wherein the charge transporting layer comprises: a compound represented by a following formula (A-1), and at least one selected from the group consisting of a compound represented by a following formula (A-2) and a compound represented by a following formula (A-3),
8 . An electrophotographic apparatus comprising: an electrophotographic photosensitive member, an exposing unit, a charging unit, a developing unit, and a transfer unit, wherein the electrophotographic photosensitive member comprises: a support, a charge generating layer, and a charge transporting layer in this order, wherein the charge transporting layer comprises: a compound represented by a following formula (A-1), and at least one selected from the group consisting of a compound represented by a following formula (A-2) and a compound represented by a following formula (A-3),

Description

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus each having the electrophotographic photosensitive member. Description of the Related Art The conventional electrophotographic apparatus has a problem of generating ghost that produces a density difference of a developing toner caused by a difference in dark decay when charged between exposed and unexposed areas. However, in recent years, due to a growing demand for higher image quality, higher process speed and higher resistance to environmental change, it is necessary to suppress the ghost more. On the other hand, the electrophotographic photosensitive member requires a highly transportable substance that rapidly extracts holes generated from a charge generating substance and prevent holes from retaining in the electrophotographic photosensitive member during one process of charging and exposure. The spatial arrangement or the highest occupied molecular orbital (called HOMO) of the charge transporting substance in the charge transporting layer is considered to cause holes to retain during the one process by acting as a carrier trap for holes. For example, the presence of low-energy HOMO levels can trap holes energetically, and the distant charge transporting substance can inhibit the carrier paths of the holes and encourage the holes to retain. Therefore, spatial expansion of HOMO and suppression of trapping sites such as energetic disorder of the charge transporting substance have been required and a charge transporting layer that can suppress trapping sites of holes and does not interfere with transfer of holes has been required. Japanese Patent Application Laid-Open No. 2013-178513 discloses that the use of a diphenylbenzidine derivative as a charge transporting substance improves the resistance against cracking attributable to a contact member and suppresses the ghost. Japanese Patent Application Laid-Open No. H10-246971 discloses that the use of a diphenylbenzidine derivative as a charge transporting substance improves image properties such as sensitivity and the residual electric potential. Japanese Patent Application Laid-Open No. 2010-2696 discloses that the use of a triarylamine derivative as a charge transporting substance suppresses carrier retain to suppress the ghost by effectively enlarging orbital expansion and overlapping. Due to a growing demand for higher image quality, higher process speed and higher resistance to environmental change in recent years, it is required to suppress the image quality degradation due to ghost phenomenon and to improve the image quality in various process conditions. Especially, it is required to suppress the ghost at the high process speed. However, as a result of the investigation by the inventors of the present invention, it was found that the evaluation machines (HP Color LaserJet 4700dn, or the like) having the process speed of 30 ppm were used for the evaluations of the electrophotographic photosensitive members in Japanese Patent Application Laid-Open No. 2013-178513, Japanese Patent Application Laid-Open No. H10-246971, and Japanese Patent Application Laid-Open No. 2010-2696, and the electrophotographic photosensitive members may not be able to sufficiently suppress the ghost in recent high-speed processes. The electrophotographic photosensitive member requires a highly transportable substance that rapidly extracts holes generated from a charge generating substance and prevent holes from retaining in the electrophotographic photosensitive member during one process of charging and exposure. The spatial arrangement or the highest occupied molecular orbital (called HOMO) of the charge transporting substance in the charge transporting layer is considered to cause holes to retain during the one process by acting as a carrier trap for holes. For example, the presence of low-energy HOMO levels can trap holes energetically, and the distant charge transporting substance can inhibit the carrier paths of the holes and encourage the holes to retain. Therefore, spatial expansion of HOMO and suppression of trapping sites such as energetic disorder of the charge transporting substance have been required. The spatial expansion of HOMO and uniformity of energy of the charge transporting substance are considered necessary. SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide an electrophotographic photosensitive member which can suppress the ghost in a high-speed process by using the charge transporting substance having the spatial expansion of HOMO and uniformity of energy. The above object is achieved by the present invention described below. That is, the electrophotographic photosensitive member according to the present invention is an electrophotographic photosensitive member comprising: a support, a charge generating layer, and a charge transporti