PURPOSE: To achieve the reduction of copying time as far as possible by adjusting the time before exposure till charging according to the number of the sheets to be copied.

CONSTITUTION: When the number of the sheets to be copied is one, the sheet number information thereof is sent to a control part 9 through a copy counter 8. The control part 9, upon receiving of the command of the control program of a ROM 10, controls the operation of its output part 11 to operate a charging charger, optical system for exposure, developing device, charger for transfer of transfer part and destaticizing charger in the first 1 cycle like b. To obtain plural sheets of copies continuously from one kind of the original, the power source for exposure lights at the first 1 cycle like b but the charging chargers and others do not operate and they start operating from the next cycle like e. Namely, the drum 1 is pre-exposed at the first 1 cycle, by which the surface potential differences of plural sheets of electrophotographs are reduced and the even image density for each sheet may be obtained.