| 摘要 |
PURPOSE:To prevent an accident caused by a jam due to separation failure of a transferring machine, by optically detecting a state of a remaining toner, and controlling a bias value to a cleaning member in accordance with quantity of the remaining toner. CONSTITUTION:Immediately before a photosensitive drum contacts with a cleaner 3, an optical sensor array consisting of a light source ane a photodetector for photodetecting a reflected ray from the drum are arranged along the drum width direction, and a sensor input is sent to an analog shift register by a driver (CCD, BBD, etc.). Its output is encoded by an A/D converter 18, density (or jam) of a remaining toner is decided by a computer 19, and in accordance with its result, the bias potential of a cleaning member is set to a proper value (a copying operation is stopped in case when a jam is detected), by which it is possible to always obtain a picture having a good quality. |
