IMAGE INPUT/OUTPUT DEVICE

PROBLEM TO BE SOLVED: To provide an image forming apparatus that suppresses deterioration of a developer by shortening a period for refreshment of the developer while suppressing reduction in productivity of printed matters. SOLUTION: The image forming apparatus 13 includes: a photoreceptor drum 1; a developing device 4 having a developing sleeve 5 capable of carrying a developer; a transfer charger 7 which transfers a developer image on the surface of the photoreceptor drum 1 to a transfer material P; an operation part 21 into which information about the basis weight of the transfer material P is input; and an engine processing part 32 capable of changing rotational speed of the developing sleeve 5. The image forming apparatus 13 is constructed so that the engine processing part 32 set the rotational speed of the developing sleeve 5 during "non-developing time" when a non-image area corresponding to the area between the adjacent transfer materials P of the area of the photoreceptor drum 1 passes through the developing sleeve 5 lower than the rotational speed of the developing sleeve 5 during "developing time" when an image area corresponding to the transfer material P of the area of the photoreceptor drum 1 passes through the developing sleeve 5 when the basis weight of the transfer material P is higher than a predetermined value. COPYRIGHT: (C)2011,JPO&INPIT