Image forming apparatus for maintaining a constant beam scanning state
US6426767B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 2000 |
| Grant date | Jul 30, 2002 |
| Priority date | — |
| Expiry date | Dec 29, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/33378
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image forming apparatus maintains a constant beam scanning state so that light beams scan each drum always in the same state once a desired color overlapping accuracy is obtained by controlling color registration in color image formation. This mechanism achieves constantly fine color overlapping without forming a test pattern several times or consuming toner unnecessarily. A beam passage switch is provided in a laser scanning system. Sensors provided near each photosensitive drum determine whether each light beam has scanned a certain portion with no inclination or a certain scanning area, or whether each image magnification provides a desired size. Sensors for detecting scanning light beam obtains the center of light beam in accordance with information on a point at which the sensors start to respond and another point at which they cease responding, for performing several types of control based on the positional information, which provides correct information even though the size or power is different over sevral light beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.