IMAGE FORMING APPARATUS

An image forming apparatus includes an image bearing member, an intermediate transfer belt, first, second, and third power sources, and a control unit. During print job execution, the control unit controls the third power source such that a discharge current supplied to the intermediate transfer belt is constant current controlled based on first and second power source current supply detection results. When changing from a first to a second discharge current, the control unit controls the third power source such that, after a first image forming region passes through a primary transfer portion, an intermediate transfer belt trailing edge to which the first discharge current is supplied initially passes through the primary transfer portion and such that, before a second image forming region passes through the primary transfer portion, an intermediate transfer belt leading edge to which the second discharge current is supplied initially passes through the primary transfer portion.