Charging roller, and process cartridge and image-forming apparatus employing the roller

• US 6,052,549 A
• Filed: 11/22/1995
• Issued: 04/18/2000
• Est. Priority Date: 11/25/1994
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Yuminamochi, Takayasu, Shimura, Masaru, Ohkubo, Masaharu
• Primary Examiner(s): Grimley, Arthur T.
• Assistant Examiner(s): Chen, Sophia S.
• Application Number:
  US08/562,366
• Time in Patent Office: 1,609 Days
• Field of Search: 355/219, 430/902, 361/214, 361/221, 361/225, 399/176
• US Class Current: 399/176
• CPC Class Codes: G03G 15/0233 Structure, details of the charging member, e.g. chemical composition, surface properties

Abstract

A charging roller is set in contact with a chargeable member to charge the chargeable member by application of voltage. The charging roller has an electroconductive support, an elastic layer formed thereon, and at least one coating layer formed on the elastic layer. The charging roller has surface roughness of not more than 8 μm, and Asker C hardness (A) of the elastic layer, and micro-rubber hardness (B) of the charging roller satisfy the relations below:

A≦45°

A<B<A+20°.

Claims

1. A charging roller set in contact with a chargeable member to charge the chargeable member by application of voltage, the charging roller comprising an electroconductive support, an elastic layer formed thereon, and at least one coating layer formed on the elastic layer, wherein the charging roller has surface roughness of not more than 8 μ

m, and Asker C hardness (A) of the elastic layer, and micro-rubber hardness (B) of the charging roller satisfy the relations below;

space="preserve" listing-type="equation">A≦

45°

space="preserve" listing-type="equation">A<

B<

A+20°

.

2. A charging roller according to claim 1, wherein the surface roughness is not less than 0.1 μ

m.

3. A charging roller according to claim 2, wherein the surface roughness ranges from 0.1 to 3 μ

m.

4. A charging roller according to claim 2, wherein the elastic layer has the Asker C hardness of not less than 10°

.

5. A charging roller according to claim 4, wherein the elastic layer has the Asker C hardness ranging from 20°

to 45°

.

6. A charging roller according to claim 1, wherein the elastic layer has the Asker C hardness of not less than 10°

.

7. A charging roller according to claim 6, wherein the elastic layer has the Asker C hardness ranging from 20°

to 45°

.

8. A charging roller according to claim 1, wherein the charging roller has micro-rubber hardness ranging of more than 45°

but not more than 55°

.

9. A charging roller according to claim 1, wherein the elastic layer has thickness ranging from 2 to 10 mm.

10. A charging roller according to claim 9, wherein the coating layer has thickness ranging from 100 to 1000 μ

m.

11. A charging roller according to claim 1, wherein the coating layer has thickness ranging from 100 to 1000 μ

m.

12. A charging roller according to claim 1, wherein the elastic layer comprises a sponge.

13. A charging roller according to claim 1, wherein the chargeable member is an electrophotographic photosensitive member.

14. A process cartridge, comprising an electrophotographic photosensitive member, and a charging roller set in contact with the electrophotographic photosensitive member to charge the electrophotographic photosensitive member by application of voltage, said-charging roller comprising an electroconductive support, an elastic layer formed thereon, and at least one coating layer formed on the elastic layer, wherein the charging roller has a surface roughness of not more than 8 μ

m, and Asker C hardness (A) of the elastic layer and micro-rubber hardness (B) of the charging roller satisfy the relations below;

space="preserve" listing-type="equation">A≦

45°

space="preserve" listing-type="equation">A<

B<

A+20°

,

and the electrophotographic photosensitive member and the charging roller are supported integrally and are demountable from the main body of an electrophotographic apparatus.

15. An electrophotographic apparatus, comprising an electrophotographic photosensitive member, a charging roller set in contact with the electrophotographic photosensitive member to charge the electrophotographic photosensitive member by application of voltage, a light irradiation means, and a developing means, said charging roller comprising an electroconductive support, an elastic layer formed thereon, and at least one coating layer formed on the elastic layer, the charging roller having a surface roughness of not more than 8 μ

m, and Asker C hardness (A) of the elastic layer and micro-rubber hardness (B) of the charging roller satisfying the relations below;

space="preserve" listing-type="equation">A≦

45°

space="preserve" listing-type="equation">A<

B<

A+20°