Bias power source controller for an image forming apparatus
US4959687A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1988 |
| Grant date | Sep 25, 1990 |
| Priority date | — |
| Expiry date | Aug 5, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/065
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A controller for controlling a bias power source associated with, for example, a developing unit of an electrophotographic copier such that a bias voltage to be applied to the developing unit for the adjustment of image density is variable in level. The controller includes a central processing unit in which a timer/event counter is built in for delivering a trigger pulse signal to trigger the power source. In order to produce a bias voltage associated with a desired density level, the trigger pulse signal is subjected to pulse width modulation control at a period which is far shorter than an output time consant of the power source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.