US 2018/0024460 A1Published application

Charging member, process cartridge and electrophotographic apparatus

AssigneeCanon Kabushiki Kaisha

InventorsAtsushi Uematsu, Tomohito Taniguchi, Masahiro Watanabe, Noboru Miyagawa, Taichi Sato, Takehiko Aoyama

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Abstract

Provided is a charging member capable of suppressing the occurrence of an image defect due to the non-uniform abrasion of a photosensitive member and a stain, in a long-term use. The charging member includes an electro-conductive elastic layer as a surface layer. The electro-conductive elastic layer contains a binder and a bowl-shaped resin particle having an opening. The surface of the charging member has a concavity and a protrusion derived from the bowl-shaped resin particle. The relations represented by the following formulae are satisfied, 0.2 ≤ S =  S   5 - S   1  S   1 ≤ 0.5 0.15 ≤ d =  d   5 - d   1  d   1 ≤ 0.5 wherein, when the charging member is pressed onto a glass plate with 100 (g) load, S1 is the average value of contact areas, dl is the average value of heights of spaces formed in a contact region; and when the load is changed to 500 (g), S5 is the average value of contact areas, d5 is the average value of heights of spaces.

Claims6

Dependent claims

A charging member comprising:

an electro-conductive substrate;
and
an electro-conductive elastic layer as a surface layer on the substrate,
wherein
the electro-conductive elastic layer
comprises a binder, and
retains a bowl-shaped resin particle having an opening, so that the opening of the bowl-shaped resin particle is exposed at a surface of the charging member;
the surface of the charging member comprises:
a concavity derived from the opening of the bowl-shaped resin particle exposed at the surface, and
a protrusion derived from an edge of the opening of the bowl-shaped resin particle exposed at the surface;
a part of the surface of the charging member is constituted by the electro-conductive elastic layer;
and
relations represented by the following formulae (1) and (2) are satisfied,
0.2
≤
S
=

S


5
-
S


1

S


1
≤
0.5
Formula


(
1
)
0.15
≤
d
=

d


5
-
d


1

d


1
≤
0.5
Formula


(
2
)
wherein
when the charging member is pressed onto a glass plate so that a load on the glass plate is 100 (g),
in a contact region R1 comprising at least one contact portion between the charging member and the glass plate in a nip between the charging member and the glass plate, S1 is defined as an average value of contact areas between the charging member and the glass plate in the respective contact portions and
d1 is defined as an average value of heights of respective spaces formed between the charging member and the glass plate in the contact region R1;
and
when the charging member is pressed onto a glass plate so that a load on the glass plate is 500 (g),
in a contact region R5 comprising at least one contact portion between the charging member and the glass plate in a nip between the charging member and the glass plate, S5 is defined as an average value of contact areas between the charging member and the glass plate in the respective contact portions and
d5 is defined as an average value of heights of respective spaces formed between the charging member and the glass plate in the contact region R5.

72 more elements

A process cartridge comprising a charging member and an electrophotographic photosensitive member and being configured to be attachable to and detachable from a main body of an electrophotographic apparatus,

wherein
the charging member comprises:
an electro-conductive substrate;
and
an electro-conductive elastic layer as a surface layer on the substrate,
wherein
the electro-conductive elastic layer
comprises a binder, and
retains a bowl-shaped resin particle having an opening, so that the opening of the bowl-shaped resin particle is exposed at a surface of the charging member;
the surface of the charging member comprises:
a concavity derived from the opening of the bowl-shaped resin particle exposed at the surface, and
a protrusion derived from an edge of the opening of the bowl-shaped resin particle exposed at the surface;
a part of the surface of the charging member is constituted by the electro-conductive elastic layer;
and
relations represented by the following formulae (1) and (2) are satisfied,
0.2
≤
S
=

S


5
-
S


1

S


1
≤
0.5
Formula


(
1
)
0.15
≤
d
=

d


5
-
d


1

d


1
≤
0.5
Formula


(
2
)
wherein
when the charging member is pressed onto a glass plate so that a load on the glass plate is 100 (g),
in a contact region R1 comprising at least one contact portion between the charging member and the glass plate in a nip between the charging member and the glass plate, S1 is defined as an average value of contact areas between the charging member and the glass plate in the respective contact portions and
d1 is defined as an average value of heights of respective spaces formed between the charging member and the glass plate in the contact region R1, and
when the charging member is pressed onto a glass plate so that a load on the glass plate is 500 (g),
in a contact region R5 comprising at least one contact portion between the charging member and the glass plate in a nip between the charging member and the glass plate, S5 is defined as an average value of contact areas between the charging member and the glass plate in the respective contact portions and
d5 is defined as an average value of heights of respective spaces formed between the charging member and the glass plate in the contact region R5.

73 more elements

An electrophotographic apparatus comprising a charging member and an electrophotographic photosensitive member,

wherein
the charging member comprises:
an electro-conductive substrate;
and
an electro-conductive elastic layer as a surface layer on the substrate,
wherein
the electro-conductive elastic layer
comprises a binder, and
retains a bowl-shaped resin particle having an opening, so that the opening of the bowl-shaped resin particle is exposed at a surface of the charging member;
the surface of the charging member comprises:
a concavity derived from the opening of the bowl-shaped resin particle exposed at the surface, and
a protrusion derived from an edge of the opening of the bowl-shaped resin particle exposed at the surface;
a part of the surface of the charging member is constituted by the electro-conductive elastic layer;
and
relations represented by the following formulae (1) and (2) are satisfied,
0.2
≤
S
=

S


5
-
S


1

S


1
≤
0.5
Formula


(
1
)
0.15
≤
d
=

d


5
-
d


1

d


1
≤
0.5
Formula


(
2
)
wherein
when the charging member is pressed onto a glass plate so that a load on the glass plate is 100 (g),
in a contact region R1 comprising at least one contact portion between the charging member and the glass plate in a nip between the charging member and the glass plate, S1 is defined as an average value of contact areas between the charging member and the glass plate in the respective contact portions and
d1 is defined as an average value of heights of respective spaces formed between the charging member and the glass plate in the contact region R1, and
when the charging member is pressed onto a glass plate so that a load on the glass plate is 500 (g),
in a contact region R5 comprising at least one contact portion between the charging member and the glass plate in a nip between the charging member and the glass plate, S5 is defined as an average value of contact areas between the charging member and the glass plate in the respective contact portions and
d5 is defined as an average value of heights of respective spaces formed between the charging member and the glass plate in the contact region R5.

73 more elements

Dependencies are inferred from the claim text.