Image forming apparatus capable of preventing an image defect caused by a variation in the shape of a belt upstream of a transfer portion

An image forming apparatus comprising:

• a belt that is rotatable and endless, and configured to bear a toner image;
• a plurality of tension rollers including an inner roller and an upstream roller arranged adjacently to the inner roller at an upstream of the inner roller in a rotational direction of the belt, wherein the plurality of tension rollers is configured to stretch the belt around the inner roller and the upstream roller;
• an outer member arranged to face the inner roller via the belt and configured to form a transfer portion at which the toner image is transferred from the belt onto a recording material, in cooperation with the inner roller;
• a pressing member configured to contact an inner circumferential surface of the belt at the upstream of the inner roller and a downstream of the upstream roller in the rotational direction of the belt, and press the inner circumferential surface of the belt toward an outer circumferential surface side;
• a moving mechanism including a moving unit movable so as to move the pressing member in a direction for pressing the belt and a direction opposite to the direction for pressing the belt;
• an attachable unit including at least one of the pressing member or the belt and configured to be attached to and detached from the image forming apparatus;
• a control unit configured to execute a mode for transferring the toner image from the belt onto the recording material by pressing the belt using the pressing member;
• and
• a storage unit configured to store information that is based on an individual difference of the attachable unit that is related to a setting of a position of the moving unit,
• wherein the control unit sets the position of the moving unit in executing the mode for transferring the toner image based on the information stored in the storage unit.