Developing roller, process cartridge, and electrophotographic apparatus

• US 8,660,472 B2
• Filed: 04/16/2012
• Issued: 02/25/2014
• Est. Priority Date: 12/28/2010
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Satoh, Hidenori, Kurachi, Masahiro, Ishida, Kazutoshi
• Primary Examiner(s): BRASE, SANDRA L
• Application Number:
  US13/447,714
• Publication Number:
  US 20120201568A1
• Time in Patent Office: 680 Days
• Field of Search: 399/279, 399/286
• US Class Current: 399/286
• CPC Class Codes: G03G 15/0818 characterised by the structure of the donor member, e.g. surface properties

Abstract

Provided is a developing roller in which: even when the roller is stored under a high-temperature, high-humidity environment over a long period of time, bleeding is suppressed; and the fusion of toner to its surface upon repeated output of images under low temperature and low humidity is suppressed. The developing roller includes: a mandrel; an elastic layer on an outer periphery of the mandrel; and a surface layer on an outer periphery of the elastic layer, in which: the surface layer contains carbon black and a polyester-polyurethane resin containing a specific structure; and the surface layer has a storage modulus E′ as measured at a temperature of 0° C. and a frequency of 10 Hz of 5 MPa or more and 20 MPa or less.

Claims

1. A developing roller comprising:

a mandrel;

an elastic layer provided on an outer periphery of the mandrel; and

a surface layer provided on an outer periphery of the elastic layer, wherein;

the surface layer comprises

carbon black, and

a polyester-polyurethane resin, and wherein

the polyester-polyurethane resin comprises the following structures A and B;

A;

a structure represented by the following chemical formula (b); and

B;

at least one structure selected from the group consisting of structures represented by the following chemical formulae (c) to (g);

2. A developing roller according to claim 1, wherein:

the structure B comprises a structure represented by the chemical formulae (c).

3. A developing roller according to claim 1, wherein:

the structure B comprises at least one structure selected from the group consisting of the structures represented by the chemical formulae (d), (e), (f) and (g).

4. A developing roller according to claim 1, wherein said polyester-polyurethane resin is formed by reacting polyester polyol containing the structure represented by the chemical formula (b) and isocyanate compound.

5. A developing roller according to claim 4, wherein said polyester polyol is one obtained from 3-caprolacton of 3-methyl-1,5-pentandiol as a raw material.

6. A developing roller according to claim 4, wherein said polyester polyol has a number-average molecular weight of from 500 to 4000.

7. A developing roller according to claim 6, wherein said polyester polyol has a number-average molecular weight of from 1000 to 3000.

8. A developing roller according to claim 4, wherein said isocyanate compound is prepolymer-type isocyanate compound derived from an isocyanate compound selected from the group consisting of TM-HDI, NBDI and DDI.

9. A developing roller according to claim 8, wherein said prepolymer-type isocyanate compound has a number average molecular weight of from 6000 to 12000.

10. A developing roller according to claim 1, wherein said elastic layer comprises a silicone rubber.

11. A process cartridge comprising:

a developing roller;

a toner-regulating member; and

a toner container,

and being so constituted as to be detachably mountable to the main body of an electrophotographic apparatus,

wherein the developing roller comprises the developing roller according to claim 1.

12. An electrophotographic image-forming apparatus, comprising:

an electrophotographic photosensitive member; and

a developing roller placed to abut the electrophotographic photosensitive member,

wherein the developing roller comprises the developing roller according to claim 1.