IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide an image forming apparatus that prevents the occurrence of scumming and unnecessary consumption of toner during stirring, even when the apparatus is started up from a state where the apparatus has been left unused for a long period and the Q/M is reduced.SOLUTION: An image forming apparatus includes a developing device, developer stirring means for stirring a developer in the developing device, and a photoreceptor arranged to face the developing device. The image forming apparatus further includes control means for controlling to make a setting value of a background potential larger than that during image formation, during stirring of developer performed before image formation at the start-up of the apparatus after being left unused for a time period beyond a reference value.