Electrophotographic photosensitive member, process cartridge and electrophotographic apparatus

• US 10,488,770 B2
• Filed: 09/19/2018
• Issued: 11/26/2019
• Est. Priority Date: 09/26/2017
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kuroiwa, Ikuyo, Kitamura, Wataru, Takizawa, Kumiko, Shimada, Tsuyoshi, Takeuchi, Eileen
• Primary Examiner(s): Rodee, Christopher D
• Application Number:
  US16/135,181
• Publication Number:
  US 20190094735A1
• Time in Patent Office: 433 Days
• CPC Class Codes: G03G 5/0542 Polyvinylalcohol, polyallylalcohol; Derivatives thereof, e.g. polyvinylesters, polyvinylethers, polyvinylamines
• CPC Class Codes: G03G 5/144 comprising inorganic material

Abstract

There is provided an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus in which residual potential is suppressed and a ghost image is prevented from being generated in a low-humidity environment in an undercoat layer of the electrophotographic photosensitive member. An electrophotographic photosensitive member including: an undercoat layer containing a strontium titanate particle having a maximum peak at a position of 2θ=32.20±0.20 (θ represents a Bragg angle) in a CuKα characteristic X-ray diffraction pattern and a half-value width of the maximum peak of 0.10 deg or more and 0.50 deg or less, and a titanium oxide particle; and a photosensitive layer containing a polyvinyl butyral resin, and a process cartridge and an electrophotographic apparatus each provided with the electrophotographic photosensitive member.

Claims

1. An electrophotographic photosensitive member, comprising:

a support, an undercoat layer, and a photosensitive layer in this order;

the undercoat layer comprising a binder resin, a titanium oxide particle and a strontium titanate particle; and

the photosensitive layer comprising a polyvinyl butyral resin, wherein

the strontium titanate particle has a maximum peak in a CuKα

characteristic X-ray diffraction pattern at a position of 2θ

=32.20±

0.20 where θ

represents a Bragg angle, and

a half-value width of the maximum peak is 0.10 to 0.50 deg.

2. The electrophotographic photosensitive member according to claim 1, wherein the half-value width is 0.10 to 0.35 deg.

3. The electrophotographic photosensitive member according to claim 1, wherein a total content of the strontium titanate particle and the titanium oxide particle in the undercoat layer is 70% by mass or more based on a content of a metal oxide in the undercoat layer, and

a mass ratio of a content of the titanium oxide particle MTi and a content of the strontium titanate particle MSr in the undercoat layer satisfy 0.25≤

MSr/MTi≤

9.0.

4. The electrophotographic photosensitive member according to claim 1, wherein the strontium titanate particle contained in the undercoat layer is surface treated with a silane coupling agent.

5. A process cartridge integrally supporting an electrophotographic photosensitive member and at least one unit selected from the group consisting of a charging unit, a developing unit, a transfer unit and a cleaning unit;

the electrophotographic photosensitive member having a support, an undercoat layer and a photosensitive layer in this order;

the process cartridge being detachably attachable to an electrophotographic apparatus main body;

the undercoat layer comprising a binder resin, a titanium oxide particle and a strontium titanate particle; and

the photosensitive layer comprising a polyvinyl butyral resin, wherein

the strontium titanate particle has a maximum peak in a CuKα

characteristic X-ray diffraction pattern at a position of 2θ

=32.20±

0.20 where θ

represents a Bragg angle, and

a half-value width of the maximum peak is 0.10 to 0.50 deg.

6. An electrophotographic apparatus, comprising:

an electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, and a transfer unit;

the electrophotographic photosensitive member having a support, an undercoat layer and a photosensitive layer in this order;

the undercoat layer comprising a binder resin, a titanium oxide particle and a strontium titanate particle; and

the photosensitive layer comprising a polyvinyl butyral resin, wherein

the strontium titanate particle has a maximum peak in a CuKα

characteristic X-ray diffraction pattern at a position of 2θ

=32.20±

0.20 where θ

represents a Bragg angle, and

a half-value width of the maximum peak is 0.10 to 0.50 deg.

7. The electrophotographic apparatus according to claim 6, wherein the charging unit comprises a charging roller disposed so as to contact the electrophotographic photosensitive member, said charging unit being configured to charge the electrophotographic photosensitive member by applying only direct-current voltage to the charging roller.