| 摘要 |
PROBLEM TO BE SOLVED: To prevent the sticking of a useless developer to an image carrier, by immediately stopping an electrifying operation and switching a developer into a noncontact state, before the bottom end of the electrifying region of the surface of the image carrier passes through a developing region, so as to stop the application of a developing bias voltage, at the time of making an emergency stop. SOLUTION: When an emergency stop is made during image forming operation, an electrifying control driving part 503 is controlled to stop the electrifying operation of an electrifying charger. Almost simultaneously with this a developing revolver driving part 506 is controlled to rotate a revolver developing unit, so that a developing unit at a developable position is retreated to separate the developer from the surface of a photoreceptor drum. Then, a photoreceptor driving part 507 is controlled to turn off a photoreceptor motor for rotary drive. The developing bias voltage corresponding to the potential by electrification of the photoreceptor drum is applied to a developing roller, until the developer becomes the noncontact state. Thus, the useless developer is never stuck to the photoreceptor drum. Further, after switching into the noncontact state, the useless developer is never stuck. |
