Method and device for preventing formation of background image in electrophotographic image forming apparatus
US5956550A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 7, 1998 |
| Grant date | Sep 21, 1999 |
| Priority date | — |
| Expiry date | May 7, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/021
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An electrophotographic image forming apparatus prevents the formation of a background image. The apparatus includes a photosensitive drum with a ground plate, and a power supply for applying a negative voltage to the ground plate in the case where the apparatus is powered on after a long time in the power-off state, or where the apparatus is powered on for many hours without forming an image. The applied negative voltage has a potential lower than a critical potential where the toner deposited on a developing roller can move to the photosensitive drum. Further, the negative voltage is applied to the ground plate, only while the charge location on the photosensitive drum rotates to reach a developing position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.