PURPOSE: To prevent the deterioration of the printing quality by turning a photosensitive drum at every necessary time by counting from the end time point of a printing cycle, and cleaning the surface of the photosensitive drum, in a dead time zone extending from a usual printing cycle and time point to the next printing cycle start.

CONSTITUTION: A time monitoring control part 16 is provided between a control part 11 and a photosensitive drum driving part 14, and has a function for operating the photosensitive driving part 14 under a necessary time management. When a usual printing cycle and time point is confirmed, for instance, a timer switch for time management is provided, and by resetting this timer switch, a time measurement is started. When a printing start signal is not detected, the time measurement is continued, whether the time measurement reachs a necessary time or not is monitored, and when it reachs the necessary set time, the photosensitive drum is turned by driving the photosensitive drum driving part 14, and the cleaning of the surface of the photosensitive drum is executed by driving a cleaning driving part 15.