Developing roller, process cartridge and electrophotographic image forming apparatus
US10895823B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 2020 |
| Grant date | Jan 19, 2021 |
| Priority date | — |
| Expiry date | May 8, 2040 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/0861
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A developing roller that enables the image density of electrophotographic images to be kept uniform even when used in an environment at a high temperature and a high humidity for a long period. The developing roller includes an electro-conductive mandrel and an electro-conductive layer on the mandrel, having an outer surface constituted by at least a first region which is electrically insulating, and a second region, the second region having higher electro-conductivity than that of the first region, the first region being arranged adjacent to the second region, the first region being disposed on an outer surface of the electro-conductive layer, the first region having a Vickers hardness of 10.0 or more as measured at an outer surface thereof, and the first region having a fracture toughness value of 800 Pa·m0.5 or more as measured at the outer surface thereof by an indentation fracture method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.