Developer carrier of a developing device for an image forming apparatus
US5105226A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 17, 1990 |
| Grant date | Apr 14, 1992 |
| Priority date | — |
| Expiry date | Oct 17, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2221/0005
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A developer carrier in the form of a developing roller constituting a part of one of a plurality of developing units incorporated in a color developing device which is mounted on an electrophotographic image forming apparatus. Latent images electrostatically formed on a photoconductive element included in the image forming apparatus each is developed by a magnet brush formed by the developer of particular color on associated one of the developing rollers. Each developing roller has a non-magnetic conductive base, a first layer formed on the base and having an insulation resistance greater than 10.sup.6 ohms, and a second layer formed on the first layer and having an insulation resistance lying in the range of 10.sup.4 ohms to 10.sup.9 ohms. The developing roller prevents a bias being applied thereto for development from leaking due to scratches or similar defects of the photoconductive element. While the developing device is in operation, a magnet brush is prevented from being formed on the developing rollers of those developing units which are not joining in the development.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.