PURPOSE: To enable residual charge or the like on a photoreceptor to be perfectly erased, by starting cleaning rotation of a photoreceptor instantly based on receiving copying start command, after the temp. condition a fixing heater for saving power has been released.

CONSTITUTION: A fixing heater can be controlled in a fixing temp. mode for retaining it at a fixing temp. and in a power saving mode for keeping it at a power saving temp. For example, a series of copying actions (T0WT1) have been finished, and after lapse of a prescribed time, the fixing temp. mode is changed into the power saving mode, and a power saving lamp is lighted. Upon turning on a key input (time T2), the power saving signal is stopped, the power saving mode is released, and a power saving lamp driving signal is produced in pulses. Upon printing start command (turning on a copy start key), preliminary rotation of a photosensitive drum is instantly started to clean the drum, and residual potential and memory are removed until the fixing heater reaches the fixing temp.