| 摘要 |
PURPOSE: To save power consumption without sacrificing a first copying work time when a standby state is shifted to a copying operation state as for a laser printer. CONSTITUTION: The revolving speed N4 of a first rotary polygon mirror Y is set to be smaller than the revolving speed N5 required for writing and larger than the revolving speed of the other rotary polygon mirrors in the standby term of an image forming device (until the time t1 from the time t0 ). Then, the revolving speed of the rotary polygon mirrors are controlled to be successively small in the disposing order thereof. At this time, when an image forming instruction is inputted, the revolving speed of the rotary polygon mirrors successively become the revolving speed N5 required for writing in the arriving order of forms. Then, the effect of a starting time is evaded from being exerted on the copying work time. |
