PURPOSE: To obtain an excellent copy sheet free of a picture breakdown by transferring toner which is not transferred and remains on an image carrier surface to copying paper and then controlling to clean when a paper source is turned on after a jam is removed.

CONSTITUTION: If a jam occurs, an instruction JAMP.JAM is written in an address 00 of an RAM in a micrcomputer. When the jamming paper is removed and the power source is turned on again, the program counter of the CPU in the MC indicates the address 00 where the instruction for a jump to an address JAM is stored, so a photosensitive drum 2 is driven; and an image formation start point A is detected by a sensor S and transmitted to the MC, which advances to copying operation. Then, the copying paper is fed into a machine and a transfer part transfers a toner image which is not transferred to the copying paper at all and remains on the surface of the photosensitive drum 2 in case of the jamming or due to a deficiency of transfer to the copying paper, thus reducing the toner. Consequently, cleaning operation is carried out normally without placng a load on a cleaning device 9.