IMAGE FORMING APPARATUS

An image forming apparatus includes an image carrier, an electrification device, an exposing device, developing device, and a control unit. The developing device includes a developing roller for supplying toner to the image carrier, a developing container for storing developer containing the toner, and a seal member for preventing leakage of the toner from a gap between the image carrier and the developing container. The control unit is capable of executing a seal member cleaning mode, in which it forms an electrostatic latent image pattern having exposed parts and unexposed parts whose boundaries exist at a predetermined or less interval over the entire area in a width direction of an image forming area of the image carrier when an image is not being formed, and drives the image carrier to rotate so that the electrostatic latent image pattern passes the seal member.