Charge rollers having improved layer structure and/or surface characteristics in an image forming apparatus
AssigneeRicoh Company, Ltd.
InventorsJunji Kurokawa, Kazuo Nojima, Masaki Sekizawa
Life of this patent
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Abstract
An image forming apparatus including a charge roller for providing a charge to a photoconductive member. The charge roller includes a metallic core with a conductive elastic layer covering the metallic core and a surface layer covering the elastic layer. The conductive elastic layer is preferably formed of an epichlorohydrein rubber or a urethane rubber. In addition, the conductive elastic layer and surface layer preferably have thickness and roughness characteristics as discussed herein.
Claims26
A charge roller for an image forming apparatus in which the charge roller charges a photoconductive member, the charge roller including a metallic core, a conductive elastic layer covering the metallic core, and a surface layer covering the conductive elastic layer;
- wherein a ten-point mean surface roughness Rd of the conductive elastic layer and a surface roughness Rs of the surface layer satisfy the following relationships:
- Rd>Rs,
- 5 .mu.m<Rd<15 .mu.m.
A charge roller for an image forming apparatus in which the charge roller charges a photoconductive member, the charge roller including a metallic core, a conductive elastic layer covering the metallic core, and a surface layer covering the conductive elastic layer;
- wherein a surface roughness Rd of the conductive layer and a surface roughness Rs of the surface layer satisfy the following relationships:
- 5 .mu.m<Rd<15 .mu.m,
- Rd>Rs,
- 3 .mu.m<Rs<10 .mu.m;
- and
- wherein the conductive elastic layer has a hardness of at least 40 defined by JISA (Japanese Industrial Standard type A K6301).
A charge roller for an image forming apparatus in which the charge roller charges a photoconductive member, the charge roller including a metallic core, a conductive elastic layer covering the metallic core, and a surface layer covering the conductive elastic layer;
- wherein a surface roughness Rd of the conductive elastic layer and a surface roughness Rs of the surface layer satisfy the following relationships:
- 5 .mu.m<Rd<15 .mu.m,
- 3 .mu.m<Rs<10 m,
- and
- Rd>Rs.
A charge roller for an image forming apparatus in which the charge roller charges a photoconductive member, the charge roller including a metallic core, a conductive elastic layer covering the metallic core, and a surface layer covering the conductive elastic layer;
- wherein the conductive elastic layer is a polar synthetic rubber with an electrical resistance of 10.sup.7 -10.sup.10 .OMEGA.-cm;
- wherein a surface roughness Rd of the conductive elastic layer satisfies the following relationship:
- 5 .mu.m<Rd<15 .mu.m;
- and
- a power source, wherein said power source is a DC power source.
A charge roller for an image forming apparatus in which the charge roller charges a photoconductive member, the charge roller including a metallic core, a conductive elastic layer covering the metallic core, and a surface layer covering the conductive elastic layer;
- wherein the conductive elastic layer has a hardness defined by JISA (Japan Industrial Standard type A K6301) of at least 40;
- and
- wherein a surface roughness Rd of the conductive elastic layer satisfies the following relationship:
- 5 .mu.m<Rd<15 .mu.m.
A charge roller for an image forming apparatus in which the charge roller charges a photoconductive member, the charge roller including a metallic core, a conductive elastic layer covering the metallic core, said conductive elastic layer including a conductive rubber material, and a surface layer covering the conductive elastic layer;
- wherein a surface roughness Rs of the surface layer is 3-10 .mu.m, and wherein a surface roughness Rd of the conductive elastic layer is 5-15 .mu.m.
A charge roller for an image forming apparatus in which the charge roller charges a photoconductive member, the charge roller including a metallic core, a conductive elastic layer covering the metallic core, and a surface layer covering the conductive elastic layer;
- wherein the surface layer has an electrical resistance of 10.sup.9 -10.sup.12 .OMEGA.-cm;
- and
- wherein said conductive elastic layer has a surface roughness such that said conductive elastic layer includes peak areas and trough areas, and wherein said surface layer is a thin film formed of a non-adhesive resin, said surface layer having a varying thickness with a maximum thickness disposed above said trough areas and a minimum thickness disposed above said peak areas;
- and
- wherein a thickness of the surface layer is 5-30 .mu.m.
Dependencies are inferred from the claim text.