Image forming apparatus having density control
US5189441A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 1991 |
| Grant date | Feb 23, 1993 |
| Priority date | — |
| Expiry date | May 1, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/043
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an electrophotographic image forming apparatus wherein raster scan of a laser beam is carried out to expose the sensitized photoconductor and the gradation is expressed with intensity modulation method, the duration of the light-emitting time for forming a dot is made smaller than the whole period needed for scanning a region assigned for a dot, while the maximum light intensity is changed according to a ratio of the duration of the light-emitting time to the whole period. Further, a plurality of modes each having a duty ratio different from each other may be provided and the maximum light intensity is changed according to the duty ratio so that the mean quantity of light for a dot is equal to each other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.