Developer carrying member and developing apparatus

• US 6,952,551 B2
• Filed: 10/28/2003
• Issued: 10/04/2005
• Est. Priority Date: 10/30/2002
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ishii, Yasuyuki, Koyanagi, Masato
• Primary Examiner(s): Lee, Susan
• Application Number:
  US10/693,859
• Publication Number:
  US 20040240910A1
• Time in Patent Office: 707 Days
• Field of Search: 399/286, 399/279, 399/265, 492/30, 492/59
• US Class Current: 399/286
• CPC Class Codes: G03G 15/0818 characterised by the structure of the donor member, e.g. surface properties

Abstract

The invention provides a developer carrying member for carrying a developer for developing an electrostatic image formed on an image bearing member, including an elastic layer, and a surface layer provided on a surface of the developer carrying member and including a resin and particles, wherein the particles have a property of being frictionally charged in a polarity opposite to a normal charging polarity of the developer, and the particles are exposed from the surface in an area rate within a range from 15 to 60% with respect to a surface area of the developer carrying member. In this manner, an uneven heating of the toner image can be suppressed even if the recording material generates an undulation after passing a nip.

Claims

1. A developer carrying member for carrying a developer for developing an electrostatic image formed on an image bearing member, comprising:

an elastic layer; and

a surface layer provided on a surface of said developer carrying member and including a resin and particles;

wherein the particles have a property of being frictionally charged in a polarity opposite to a normal charging polarity of the developer, and

the particles are exposed from said surface in an area rate within a range from 15 to 60% with respect to a surface area of said developer carrying member.

2. A developer carrying member according to claim 1, wherein said particles are dispersed in the resin.

3. A developer carrying member according to claim 1, wherein said developer carrying member includes a conductive material and has an electrical resistance within a range from 10⁴ to 10⁸ Ω

.

4. A developer carrying member according to claim 1, wherein said surface layer has a thickness from 5 to 30 μ

m.

5. A developer carrying member according to claim 1 or 4, wherein said particles have a particle size within a range of 10 to 30 μ

m.

6. A developer carrying member according to claim 1, wherein said particles have a particle size larger than a thickness of said surface layer.

7. A developer carrying member according to claim 1, wherein said developer carrying member has a surface roughness in a ten-point averaged roughness Rz of 6 to 9 μ

m.

8. A developer carrying member according to claim 1, wherein said developer carrying member has a roller shape.

9. A developer carrying member according to claim 1, wherein a layer of said developer carried on said developer carrying member is regulated by a developer regulating member to a thickness of 6 to 20 μ

m.

10. A developing apparatus comprising:

a developer carrying member for carrying a developer for developing an electrostatic image formed on an image bearing member, the developer carrying member including;

an elastic layer; and

a surface layer provided on a surface of said developer carrying member and including a resin and particles;

wherein the particles have a property of being frictionally charged in a polarity opposite to a normal charging polarity of said developer, and

said particles are exposed from said surface in an area rate within a range from 15 to 60% with respect to a surface area of said developer carrying member.

11. A developing apparatus according to claim 10, wherein said particles are dispersed in said resin.

12. A developing apparatus according to claim 10, wherein said developer carrying member includes a conductive material and has an electrical resistance within a range from 10⁴ to 10⁸ Ω

.

13. A developing apparatus according to claim 10, wherein said surface layer has a thickness from 5 to 30 μ

m.

14. A developing apparatus according to claim 10 or 13, wherein said particles have a particle size within a range of 10 to 30 μ

m.

15. A developing apparatus according to claim 10, wherein said particles have a particle size larger than a thickness of said surface layer.

16. A developing apparatus according to claim 10, wherein said developer carrying member has a surface roughness in a ten-point averaged roughness Rz of 6 to 9 μ

m.

17. A developing apparatus according to claim 10, wherein said developer carrying member has a roller shape.

18. A developing apparatus according to claim 10, wherein a layer of said developer carried on said developer carrying member is regulated by a developer regulating member to a thickness of 6 to 20 μ

m.

19. A developing apparatus according to claim 10, wherein said developing apparatus is provided in a process cartridge detachably mountable in a main body of an image forming apparatus.

20. A developing apparatus according to claim 10, wherein said developing apparatus is provided in an image forming apparatus including said image bearing member.