Electrophotographic image forming apparatus having charge transport layer with matrix-domain structure and charging member having concavity and protrusion

• US 9,274,442 B2
• Filed: 03/18/2015
• Issued: 03/01/2016
• Est. Priority Date: 03/27/2014
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Sato, Taichi, Taniguchi, Tomohito, Miyagawa, Noboru, Aoyama, Takehiko, Uematsu, Atsushi, Watanabe, Masahiro, Yamamoto, Yuki, Ogaki, Harunobu, Maruyama, Akihiro, Anezaki, Takashi, Miura, Daisuke, Kumoi, Hirofumi
• Primary Examiner(s): GRAY, FRANCIS C
• Application Number:
  US14/662,228
• Publication Number:
  US 20150277244A1
• Time in Patent Office: 349 Days
• US Class Current: 1/1
• CPC Class Codes: G03G 15/0233 Structure, details of the charging member, e.g. chemical composition, surface properties
• CPC Class Codes: G03G 5/04 Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
• CPC Class Codes: G03G 5/056 Polyesters
• CPC Class Codes: G03G 5/0564 Polycarbonates
• CPC Class Codes: G03G 5/0578 Polycondensates comprising silicon atoms in the main chain
• CPC Class Codes: G03G 5/0592 Macromolecular compounds characterised by their structure or by their chemical properties, e.g. block polymers, reticulated polymers, molecular weight, acidity
• CPC Class Codes: G03G 5/0596 Macromolecular compounds characterised by their physical properties

Abstract

Provided an electrophotographic image forming apparatus comprising an electrophotographic photosensitive member and a charging member. The electrophotographic photosensitive member includes a charge transport layer as a surface layer having a matrix-domain structure including specific resins. The charging member comprises an electro-conductive substrate, and an electro-conductive elastic layer. The electro-conductive elastic layer comprises a binder, and holding a bowl-shaped resin particle having an opening, so that at least a part of the bowl-shaped resin particle is exposed, and the charging member has a concavity derived from the opening of the bowl-shaped resin particle on the surface thereof, and a protrusion derived from an edge of the opening of the bowl-shaped resin particle on the surface thereof.

Claims

1. An electrophoto graphic image forming apparatus comprising:

an electrophotographic photosensitive member,

a charging unit in contact with the electrophotographic photosensitive member so as to charge the electrophotographic photosensitive member with a charging member, and

a developing unit which supplies toner to the electrophotographic photosensitive member on which an electrostatic latent image is formed, to form a toner image on the electrophotographic photosensitive member;

wherein,

the electrophotographic photosensitive member comprises;

a support,

a charge generation layer disposed on the support, and

a charge transport layer disposed on the charge generation layer;

the charge transport layer is a surface layer of the electrophotographic photosensitive member,

the charge transport layer has a matrix-domain structure comprising a matrix and a domain,

the domain comprises a polyester resin A having;

a structural unit represented by the following Formula (A) and

a structural unit represented by the following Formula (B), and

the matrix comprises;

at least one resin selected from the group consisting of a polyester resin C having a structural unit represented by the following Formula (C) and a polycarbonate resin D having a structural unit represented by the following Formula (D) and

a charge transport substance,

wherein,

the charging member comprises

an electro-conductive substrate, and

an electro-conductive elastic layer;

the electro-conductive elastic layer comprising a binder, and holding a bowl-shaped resin particle having an opening, so that at least a part of the bowl-shaped resin particle is exposed, and

the charging member has

a concavity derived from the opening of the bowl-shaped resin particle on the surface thereof, and a protrusion derived from an edge of the opening of the bowl-shaped resin particle on the surface thereof;

the protrusion on the surface of the charging member coming into contact with the electrophotographic photosensitive member;

2. The electrophotographic image forming apparatus according to claim 1, wherein the content of the structural unit represented by Formula (A) based on the total mass of the polyester resin A in the domain is 6% by mass or more and 40% by mass or less.

3. The electrophotographic image forming apparatus according to claim 1, wherein the content of the structural unit represented by Formula (B) based on the total mass of the polyester resin A in the domain is 60% by mass or more and 94% by mass or less.

4. The electrophotographic image forming apparatus according to claim 1, wherein the weight average molecular weight of the polyester resin A in the domain is 30,000 or more and 200,000 or less.

5. The electrophotographic image forming apparatus according to claim 1, wherein the number average particle size of the domain containing the polyester resin A is 100 nm or more and 1,000 nm or less.

6. The electrophotographic image forming apparatus according to claim 1, wherein the bowl-shaped resin particle to form the protrusion of the charging member is selected from the group consisting of an acrylonitrile resin, a vinyl chloride resin, a vinylidene chloride resin, a methacrylic acid resin, a styrene resin, an urethane resin, an amide resin, a methacrylonitrile resin, an acrylic acid resin, an acrylic acid ester resin, and a methacrylic acid ester resin.

7. The electrophotographic image forming apparatus according to claim 1, wherein the difference in height between the apex of the protrusion derived from the edge of the opening of the bowl-shaped resin particle and the bottom of the concavity derived from the opening of the bowl-shaped resin particle of the charging member is 5 μ

m or more and 100 μ

m or less.

8. The electrophotographic image forming apparatus according to claim 1, wherein the bowl-shaped resin particle of the charging member has a maximum diameter of 5 μ

m or more and 150 μ

m or less.

9. The electrophotographic image forming apparatus according to claim 1, wherein the bowl-shaped resin particle of the charging member has a ratio of the maximum diameter of the bowl-shaped resin particle to the minimum diameter of the opening ([maximum diameter]/[minimum diameter of opening]) of 1.1 or more and 4.0 or less.

10. The electrophotographic image forming apparatus according to claim 1, wherein the charging member has a ratio of the maximum diameter of the bowl-shaped resin particle to the difference in height between the apex of the protrusion derived from the edge of the opening of the bowl-shaped resin particle and the bottom of the concavity derived from the opening of the bowl-shaped resin particle ([maximum diameter]/[difference in height]) of 0.8 or more and 3.0 or less.

11. The electrophotographic image forming apparatus according to claim 1, wherein the bowl-shaped resin particle of the charging member has a shell thickness of 0.1 μ

m or more and 3 μ

m or less.

12. The electrophotographic image forming apparatus according to claim 1, wherein the content of the polyester resin A is 10% by mass or more and 40% by mass or less based on the total mass of all the resins in the charge transport layer.

13. The electrophotographic image forming apparatus according to claim 1, wherein the surface of the charging member has a ten-point average roughness (Rzjis) of 5 μ

m or more and 65 μ

m or less.

14. The electrophotographic image forming apparatus according to claim 1, wherein the charging member has an average interval of surface irregularities (Sm) of 20 μ

m or more and 200 μ

m or less.