Image forming apparatus for synthesizing a differential peak signal and an image signal
US5633669A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 26, 1994 |
| Grant date | May 27, 1997 |
| Priority date | — |
| Expiry date | Jan 26, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/40037
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a digital image forming apparatus, the intensity or the pulse width of laser beam exposure is modulated according to image signals of a document detected by a sensor. A peak waveform having a peak is generated in each light-emitting period of laser beam. For example, and a signal having a peak is synthesized with the image signals to generate the peak waveform. Thus, the laser is driven according to the peak waveforms so that the exposed portions on a photoconductor in correspondence to the peaks are exposed with a larger quantity of light at low densities. Then, the amount of the gamma correction can be decreased and the gradation characteristic can be stabilized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.