Developing roller, developing assembly, process cartridge and electrophotographic image forming apparatus
US7747204B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 2008 |
| Grant date | Jun 29, 2010 |
| Priority date | — |
| Expiry date | Sep 11, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/0818
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A developing roller is provided which is soft enough to enable toners to be kept from deteriorating with time and cannot easily cause permanent set. The developing roller includes a mandrel, an elastic-material layer and a cover layer as a surface layer which covers the elastic-material layer. Asker-C hardness at the surface of the cover layer is from 40° to 85°. The cover layer has a thickness of from 15 nm to 5,000 nm. Martens hardness H1 (N/mm2) at the surface of the developing roller, Martens hardness H2 (N/mm2) of the elastic-material layer and the thickness d (mm) of the cover layer satisfy the relationship of the following expression (1):400≦(H1−H2)/d≦2,000 (1).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.