Image forming apparatus that accurately detects sheet in the feeding direction, and method thereof
US6788322B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 18, 2002 |
| Grant date | Sep 7, 2004 |
| Priority date | — |
| Expiry date | Dec 18, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/04786
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image forming apparatus has a CIS disposed in an area where a sheet passes in such a fashion that read pixels of the CIS are arranged in a direction perpendicular to the feeding direction of the sheet. A part of the read pixels (e.g., 1000 pixels) that corresponds to {fraction (1/7)} of all the read pixels are repeatedly read with a short period (TS) to detect the position of the leading edge of the sheet being fed. After waiting a predetermined period of time after the timing of detection of the leading edge position of the sheet, a laser beam is irradiated onto a photosensitive drum to start writing an image in the subscanning direction. Further, read pixels (e.g., 6000 pixels) that corresponds to {fraction (6/7)} of all the read pixels are repeatedly read with a long period (TL) to detect the position of the side edge of the fed sheet. Based on the detected side edge position of the sheet, the amount of deviation of the sheet is calculated to thereby correct the writing start position in the main scanning direction of the sheet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.