An image forming apparatus may include controls for changing a state of a developing roller from a stopped state to a rotating state. The change in state may be used to avoid deterioration of toner and/or a surface of the developing roller. Changes in state may occur at various times including at a timing corresponding to an outside of an image formation area, a timing corresponding to an inside of an image formation area and the like. In one arrangement, a first developing roller may continue to rotate (e.g., during monochrome printing), while one or more other developing rollers are switched between a stopped state and a rotating state. Alternatively or additionally, a roller which is caused to change states may remain stopped between the timing corresponding to a rear end of an image formation area and a timing corresponding to a front end of an immediately subsequent image formation area.