| 摘要 |
PROBLEM TO BE SOLVED: To prevent the deterioration of image quality, such as a defective photoreceptor cleaning operation caused by toner reverse transfer development, and dirt sticking to a fixing device, in a tandem color image forming apparatus. SOLUTION: A surface potential of a photoreceptor controlled by bias application of chargers in a plurality of EP processes arranged in a paper carrying direction is reduced according as the potential shifts from EP processes disposed in an upstream side of image formation toward those disposed in a downstream side. Developing biases applied to developing rolls in developing devices of EP processes are increased according as the biases shift from EP processes disposed in the upstream side toward those disposed in the downstream side. Or bias voltages applied to first transfer rolls in transfer devices of EP processes are increased according as the voltages shift from EP processes disposed in the upstream side of image formation toward those disposed in the downstream side. COPYRIGHT: (C)2006,JPO&NCIPI
|
