An image forming apparatus having an image bearing member for bearing an electrostatic image to be developed by toner, a transfer device for transferring a toner image formed on the image bearing member onto a transfer material, and developing and cleaning device for developing the electrostatic image with developer including toner and carrier and for cleaning residual toner remaining on the image bearing member after transferring, the developing and cleaning device having a developer bearing member for bearing the developer and serving to effect development and cleaning by causing a magnet brush formed by the carrier to contact with the image bearing member, and wherein the following relation is satisfied:.vertline.V.sub.s1 V.sub.dr .vertline./.vertline.V.sub.dr .vertline..times.L.times.m.times..alpha..gtoreq.7(where, V.sub.s1 is a moving speed (mm/sec.) of a surface of the developer bearing member, V.sub.dr is a moving speed (mm/sec.) of a surface of the image bearing member, L is a contact width (mm) of the brush in a moving direction of the image bearing member, m is a cross-sectional area (mm.sup.2) of the magnet brush, and .alpha. is density (flux/mm.sup.2) of the magnet brush).