Image forming apparatus with self-cleaning

摘要

The image forming apparatus includes an image bearing member; a transfer belt used to transfer a toner image from the image bearing member to a transfer material; a transfer unit adapted to form a transfer nip in conjunction with the image bearing member through the transfer belt; and a control part adapted to control a rotation direction of the transfer belt, wherein in a cleaning mode, the control part rotates the transfer belt in a direction opposite to the rotation direction of the transfer belt during image formation at least by an amount equal to or larger than width of the transfer nip in the rotation direction of the transfer belt. This prevents foreign material from being trapped between the transfer belt such as an intermediate transfer belt or transfer material conveyance belt and a sheet member and thereby reduces density irregularities in a longitudinal direction of the belt.