Color image forming device which changes developing bias when switching between developer units
US5671470A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1995 |
| Grant date | Sep 23, 1997 |
| Priority date | — |
| Expiry date | Oct 23, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/0177
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An image forming device includes a plurality of developing devices and a photosensitive drum. Each of the developing devices includes a developer carrying roller. One of the developing devices is moved to a developing position confronting the photosensitive drum which is formed with a latent image. A first developing bias including a d.c. component and an a.c. component is applied to the developer carrying roller and developer on the developer carrying roller is rendered in contact with the latent image on the photosensitive drum so that the latent image is developed. On the other hand, when the developer on the developer carrying roller comes in contact with and separates from the photosensitive drum due to the movement of the developing device, a second developing bias is applied to the developer carrying roller. The second developing bias generates an electric field where the developer on the developer carrying roller is more reluctant to move toward the photosensitive drum as compared with the first developing bias. The second developing bias may include only a d.c. component.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.