Developing member having outer surface with independent electrically insulating domains, electrophotographic process cartridge, and electrophotographic image forming apparatus

• US 10,642,186 B2
• Filed: 02/20/2019
• Issued: 05/05/2020
• Est. Priority Date: 02/26/2018
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sakurai, Yuji, Nakamura, Minoru, Sugiyama, Ryo, Ishida, Kazutoshi, Morishita, Hiroshi, Matsunaga, Kenta, Nakamura, Kentarou
• Primary Examiner(s): Gray, David M.
• Assistant Examiner(s): Roth, Laura
• Application Number:
  US16/280,201
• Publication Number:
  US 20190265609A1
• Time in Patent Office: 440 Days
• CPC Class Codes: G03G 15/0808 characterised by the developer supplying means, e.g. structure of developer supply roller
• CPC Class Codes: G03G 15/0818 characterised by the structure of the donor member, e.g. surface properties
• CPC Class Codes: G03G 2215/0861 Particular composition or materials

Abstract

The developing member includes a substrate, and an electroconductive layer on the substrate, wherein the electroconductive layer has electrically insulating domains on an outer surface thereof, the domains being independent from each other, the developing member has an outer surface including a surface of the electroconductive layer and surfaces of the domains, and wherein, when each of the domains is orthographically projected onto the surface of the electroconductive layer, defining respective areas of projected images of the domains as S, and defining respective areas of convex envelopes of the projected images as H, at least one domain satisfies the relation represented by 0.05≤S/H≤0.80.

Claims

1. An electrophotographic developing member, comprising:

a substrate;

an electroconductive layer on the substrate; and

electrically insulating domains on an outer surface of the electroconductive layer, the domains being independent from each other, wherein

the developing member has an outer surface including a surface of the electroconductive layer that is not coated with the domains, and surfaces of the domains, and

when observing the outer surface of the developing member with a microscope, at least one of the domains satisfies 0.05≤

S/H≤

0.80 where S is the respective areas of the observed domains and H is the respective areas of convex envelopes of the observed domains.

2. The developing member according to claim 1, wherein at least 20% of the domains satisfy 0.05≤

S/H≤

0.80.

3. The developing member according to claim 2, wherein at least 80% of the domains have an area S in the range of 300 to 100000 μ

m².

4. The developing member according to claim 2, wherein an arithmetic average of horizontal Feret'"'"'s diameters of the domains that are parallel to a longitudinal direction of the developing member is 100 to 2000 μ

m.

5. The developing member according to claim 2, wherein a sum of the areas S of the domains located in a rectangular region on the outer surface of the developing member having a side of 3.0 mm in a longitudinal direction of the developing member and a side of 1.0 mm in a circumferential direction of the developing member is 15 to 50% relative to the area of the rectangular region.

6. The developing member according to claim 1, wherein the domains have a volume resistivity of 1.0×

10¹³ to 1.0×

10¹⁸ Ω

·

cm.

7. The developing member according to claim 1, wherein the domains have a volume resistivity of 1.0×

10¹⁴ to 1.0×

10¹⁷ Ω

·

cm.

8. The developing member according to claim 1, wherein the electroconductive layer has a volume resistivity of 1.0×

10¹ to 1.0×

10¹² Ω

·

cm.

9. The developing member according to claim 1, wherein the electroconductive layer has a volume resistivity of 1.0×

10¹ to 1.0×

10¹⁰ Ω

·

cm.

10. The developing member according to claim 1, wherein the electroconductive layer comprises polyurethane resin.

11. The developing member according to claim 1, wherein the electroconductive layer contains particles forming protrusions on the outer surface of the electrophotographic member.

12. The developing member according to claim 1, wherein the domains comprises resin.

13. The developing member according to claim 12, wherein the resin is at least one member selected from the group consisting of acrylic resin, polyolefin resin, epoxy resin and polyester resin.

14. The developing member according to claim 1, wherein the domains are formed by wet coating a material for forming the domains on the outer surface of the electroconductive layer.

15. The developing member according to claim 1, wherein the domains are formed by wet coating and repelling a material forming the domains on the outer surface of the electroconductive layer.

16. The developing member according to claim 15, wherein the material has a contact angle of 10 to 90°

with respect to the outer surface of the electroconductive layer.

17. An electrophotographic process cartridge configured to be detachably mountable on an electrophotographic image forming apparatus, the electrophotographic process cartridge comprising:

a toner container containing toner; and

a developing unit that transfers the toner, the developing unit including a developing member comprising a substrate, an electroconductive layer and electrically insulating domains on an outer surface of the electroconductive layer, the domains being independent from each other, wherein

the developing member has an outer surface including a surface of the electroconductive layer that is not coated with the domains, and surfaces of the domains, and

when observing the outer surface of the developing member with a microscope, at least one of the domains satisfies 0.05≤

S/H≤

0.80 where S is the respective areas of the observed domains and H is the respective areas of convex envelopes of the observed domains.

18. An electrophotographic image forming apparatus, comprising:

an electrophotographic photosensitive member;

a charging unit disposed to be capable of charging the electrophotographic photosensitive member; and

a developing unit that feeds a toner to the electrophotographic photosensitive member, the developing unit including a developing member comprising a substrate, an electroconductive layer and electrically insulating domains on an outer surface of the electroconductive layer, the domains being independent from each other, wherein

the developing member has an outer surface including a surface of the electroconductive layer that is not coated with the domains, and surfaces of the domains, and

when observing the outer surface of the developing member with a microscope, at least one of the domains satisfies 0.05≤

S/H≤

0.80 where S is the respective areas of the observed domains and H is the respective areas of convex envelopes of the observed domains.