PURPOSE: To increase the return efficiency of the developer having been prevented of degradation by transferring the toner having been recovered in a cleaning device to the developing device via latent image carrier when no copying cycle is done.

CONSTITUTION: ;When the toner having been removed in a cleaning device 9 and recovered in a toner recovery device 15 reaches a specified amount, the toner in the recovery device 15 is transferred to a photoreceptor 1 by charging of the transfer part 8 of a photosensitive drum 2 or application of a bias potential to a cleaning magnet brush 12 in the period when no copying cycle is executed. This toner is transferred and returned to a developing treatment device 7 via brush 11 by the reverse charging of the photoreceptor 1 or the application of a reverse vias voltage to the developing magnet brush 11 in the similar manner. The toner is efficiently recovered without degradation by the return without any mechanical treatment and is reused. In addition, the degree of freedom of selection of the installation position of the cleaing device and developing device increases.