ROLLER MEMBER FOR ELECTROPHOTOGRAPHY, PROCESS CARTRIDGE AND ELECTROPHOTOGRAPHIC APPARATUS

• US 20140301754A1
• Filed: 04/03/2014
• Published: 10/09/2014
• Est. Priority Date: 04/03/2013
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Uematsu, Atsushi, Miyagawa, Noboru, Sato, Taichi
• Granted Patent: US 9,098,006 B2
• Time in Patent Office: Days
• US Class Current: 399/176
• CPC Class Codes: G03G 15/0233 Structure, details of the charging member, e.g. chemical composition, surface properties
• CPC Class Codes: G03G 15/0818 characterised by the structure of the donor member, e.g. surface properties
• CPC Class Codes: G03G 15/1685 Structure, details of the transfer member, e.g. chemical composition
• CPC Class Codes: G03G 15/2053 Structural details of heat elements, e.g. structure of roller or belt, eddy current, induction heating

Abstract

The roller member has a substrate and an electroconductive elastic layer. The elastic layer has a crown shape of which an outer diameter at the middle in the lengthwise direction is larger than those at its both ends. The elastic layer includes a bowl-shaped resin particle. The surface of the roller member has concavity derived from an opening of the bowl-shaped resin particle and a protrusion derived from an edge of the opening of the resin particle. The relation in the restoring rate for elastic deformation between at the middle of the roller member and at its both ends is such that: on the surface of the elastic layer the restoring rate is larger at both ends than that at the middle, and at the position of depth t μm from the elastic layer surface the restoring rate is larger at the middle than that at both ends.

Claims

1. A roller member for electrophotography comprising:

an electroconductive substrate and an electroconductive elastic layer as a surface layer;

wherein

the electroconductive elastic layer has a crown shape of which an outer diameter at the middle of the roller member in the lengthwise direction is larger than those at both ends of the roller member;

the electroconductive elastic layer comprises a binder and a bowl-shaped resin particle;

the surface of the roller member has a concavity derived from an opening of the bowl-shaped resin particle and a protrusion derived from an edge of the opening of the bowl-shaped resin particle; and

wherein the relation in the restoring rate of the roller member for elastic deformation between at the middle of the roller member in the lengthwise direction and at both ends of the roller member is such that;

on the surface of the electroconductive elastic layer, the restoring rate is larger at the both ends than that at the middle, and

at the position of depth t μ

m from the surface of the electroconductive elastic layer, the restoring rate is larger at the middle than that at the both ends.

2. The roller member according to claim 1, wherein the restoring rate for elastic deformation becomes smaller in the depth direction from the surface of the electroconductive elastic layer.

3. The roller member according to claim 1, wherein the depth t μ

m is 30 μ

m or more and 100 μ

m or less.

4. The roller member according to claim 1, wherein the bowl-shaped resin particle has an opening and a roundish concavity demarcated by a shell.

5. The roller member according to claim 1, wherein the distance (height difference) between the top of the protrusion derived from the edge of the opening of the bowl-shaped resin particle and the bottom of the roundish concavity demarcated by the shell of the bowl-shaped resin particle is 5 μ

m or more and 100 μ

m or less.

6. The roller member according to claim 5, wherein the distance (height difference) between the top of the protrusion derived from the edge of the opening of the bowl-shaped resin particle and the bottom of the roundish concavity demarcated by the shell of the bowl-shaped resin particle is 8 μ

m or more and 80 μ

m or less.

7. The roller member according to claim 5, wherein the ratio between the maximum diameter of the bowl-shaped resin particle and the distance (height difference) between the top of the protrusion derived from the edge of the opening of the bowl-shaped resin particle and the bottom of the roundish concavity demarcated by the shell of the bowl-shaped resin particle, [maximum diameter]/[height difference] is 0.8 or more and 3.0 or less.

8. The roller member according to claim 1, wherein the maximum diameter of the bowl-shaped resin particle is 5 μ

m or more and 150 μ

m or less.

9. The roller member according to claim 8, wherein the maximum diameter of the bowl-shaped resin particle is 8 μ

m or more and 120 μ

m or less.

10. The roller member according to claim 1, wherein the thickness of the shell of the bowl-shaped resin particle is 0.1 μ

m or more and 3 μ

m or less.

11. The roller member according to claim 10, wherein the thickness of the shell of the bowl-shaped resin particle is 0.2 μ

m or more and 2 μ

m or less.

12. The roller member according to claim 1, wherein the ten-point average roughness (Rzjis) of the surface of the roller member is 5 μ

m or more and 65 μ

m or less.

13. The roller member according to claim 1, wherein the mean concave-convex spacing (Sm) of the surface of the roller member is 30 μ

m or more and 200 μ

m or less.

14. A process cartridge comprising the roller member for electrophotography according to claim 1 and an electrophotographic photosensitive member, and being constituted to be demountable from the body of an electrophotographic apparatus.

15. An electrophotographic apparatus comprising the roller member for electrophotography according to claim 1 and an electrophotographic photosensitive member.