To provide an image forming apparatus having a developing device capable of discharging deteriorated toner and stably forming images.

The image forming apparatus includes; an image carrier; an exposure means for writing an electrostatic latent image on the image carrier based on an image signal; a developing means for forming a toner image by supplying toner onto the image carrier; a transfer means for transferring the toner image on the image carrier to a recording medium; and a cleaning means for cleaning the image carrier. The developing means has a cylindrical developing roller, a plurality of magnetic poles disposed in the developing roller, and a restricting member for restricting a quantity of conveyance of developer by the developing roller. When a pattern image for discharging toner is formed before or after a regular image area on the image carrier, the angle of at least one of the plurality of magnetic poles is switched to the angle assigned to the formation of a pattern image from that assigned to the formation of a regular image.