In a case where a rotating speed of an intermediate transfer member is reduced during the process of image formation, carriers may adhere to a photosensitive member before the rotating speed of the intermediate transfer member stabilizes. To cope therewith, in changing an image formation speed in accordance with a conveying speed of a recording material on completion of primary transfer, a developing rotary is rotated so as to keep any developing device off a developing position. Consequently, a situation in which the carriers adhere to an image bearing member can be avoided. At the same time, stopping a charging operation of a charger enables a longer service life of the image bearing member.