CHARGING MEMBER, PROCESS CARTRIDGE, AND ELECTROPHOTOGRAPHIC APPARATUS

• US 20160062259A1
• Filed: 08/27/2015
• Published: 03/03/2016
• Est. Priority Date: 08/29/2014
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Miyagawa, Noboru, Taniguchi, Tomohito, Watanabe, Masahiro, Sato, Taichi, Aoyama, Takehiko, Uematsu, Atsushi
• Granted Patent: US 9,304,429 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G03G 15/0233 Structure, details of the charging member, e.g. chemical composition, surface properties

Abstract

A charging member includes an electro-conductive substrate and an electro-conductive resin layer. The electro-conductive resin layer contains a binder, a plurality of bowl-shaped resin particles, and a plurality of hollow particles. The charging member has a surface having recesses due to openings of the bowl-shaped resin particles and protrusions due to edges of the openings of the bowl-shaped resin particles, where the positional relationship between one bowl-shaped resin particle and the hollow particles lying in the vicinity of the bowl-shaped resin particle is that the number of the hollow particles being in the space under the bowl-shaped resin particle in a predetermined depth is at least four in average.

Claims

1. A charging member comprising an electro-conductive substrate and an electro-conductive resin layer, wherein

the electro-conductive resin layer includes a binder, a plurality of bowl-shaped resin particles, and a plurality of hollow particles;

the charging member has a surface having recesses defined by openings of the bowl-shaped resin particles and protrusions defined by edges of the openings of the bowl-shaped resin particles; and

the electro-conductive resin layer satisfies a positional relationship between the bowl-shaped resin particles and the hollow particles defined by requirement (1);

requirement (1);

at least 4.0 hollow particles existing within a region, the region being defined by orthographic projection of the bowl-shaped resin particle from the surface of the electro-conductive resin layer toward the depth direction, and being between

an outer wall surface of a shell forming the recess of the bowl-shaped resin particle, and

a plane M₂ which is parallel to the surface of the electro-conductive substrate and is passing through a point p₂ at a distance d of b/(1+√

2) (μ

m) in the depth direction, from a point p₁ at a deepest position of the outer wall surface of the shell, where the symbol b in “

b/(1+√

2)”

represents a particle diameter (μ

m) of the bowl-shaped resin particle by spherical approximation.

2. The charging member according to claim 1, wherein

the hollow particles each have a particle diameter c determined by spherical approximation within a range of b/5 (μ

m) or more and b/(1+√

2) (μ

m) or less.

3. The charging member according to claim 1, wherein the particle diameter b is 50 μ

m or more and 150 μ

m or less.

4. A process cartridge detachably attachable to a main body of an electrophotographic apparatus, comprising a charging member, wherein the charging member comprises an electro-conductive substrate and an electro-conductive resin layer, wherein

the electro-conductive resin layer includes a binder, a plurality of bowl-shaped resin particles, and a plurality of hollow particles;

the charging member has a surface having recesses defined by openings of the bowl-shaped resin particles and protrusions defined by edges of the openings of the bowl-shaped resin particles; and

the electro-conductive resin layer satisfies a positional relationship between the bowl-shaped resin particles and the hollow particles defined by requirement (1);

requirement (1);

at least 4.0 hollow particles existing within a region, the region being defined by an orthographic projection of the bowl-shaped resin particle from the surface of the electro-conductive resin layer toward a depth direction, and being between

an outer wall surface of a shell forming the recess of the bowl-shaped resin particle, and

a plane M₂ which is parallel to the surface of the electro-conductive substrate and is passing through a point P2 at a distance d of b/(1+√

2) (μ

m) in the depth direction, from a point p₁ at a deepest position of the outer wall surface of the shell, where the symbol b in “

b/(1+√

2)”

represents a particle diameter (μ

m) of the bowl-shaped resin particle by spherical approximation.

5. An electrophotographic apparatus comprising a charging member, an exposure device, and a developing device, wherein the charging member comprises an electro-conductive substrate and an electro-conductive resin layer, wherein

the electro-conductive resin layer contains a binder, a plurality of bowl-shaped resin particles, and a plurality of hollow particles;

the charging member has a surface having recesses defined by openings of the bowl-shaped resin particles and protrusions defined by edges of the openings of the bowl-shaped resin particles; and

the electro-conductive resin layer satisfies a positional relationship between the bowl-shaped resin particles and the hollow particles defined by requirement (1);

requirement (1);

at least 4.0 hollow particles existing within a region, the region being defined by an orthographic projection of the bowl-shaped resin particle from the surface of the electro-conductive resin layer toward a depth direction, and being between

an outer wall surface of a shell forming the recess of the bowl-shaped resin particle, and

a plane M₂ which is parallel to the surface of the electro-conductive substrate and is passing through a point P2 at a distance d of b/(1+√

2) (μ

m) in the depth direction, from a point p₁ at the deepest position of the outer wall surface of the shell, where the symbol b in “

b/(1+√

2)”

represents a particle diameter (μ

m) of the bowl-shaped resin particle by spherical approximation.