| 摘要 |
PURPOSE:To assure the stability of an image forming device by making it possible to obtain high-quality images free from sweeping and thinning and to make development without generating spark discharge with an image carrying member even in a high land area. CONSTITUTION:A falling regulation bias is used as a developing bias. The time T12 of a falling process (C) from a toner energizing process (A) in a developing sleeve direction to a toner energizing process (B) of a photosensitive drum direction in one period of the AC component thereof and the time T11 of the process (B) are so regulated as to attain 10.0<=T11/(T11+T12)X100<=90.0. Further, the device is provided with a regulating means for the potential Vmax of the process (B). The reciprocating motion of the toners at the ends between SD is suppressed by such bias to prevent the sweeping and the reciprocating motion of the toners in the central part between the SD is made sufficient to prevent the thinning. Further, the Vmax value is maximized within the leak threshold value on a flat land, by which high development efficiency is attained. The development with the suppressed spark discharge is executed by setting the Vmax value within the leak threshold value of the high land at the high land. |
