Image forming apparatus

An image forming apparatus comprising:

• a belt unit having an intermediate transfer belt and configured to be detachably attachable to a main body of the image forming apparatus in an insertion direction of the belt unit, which intersects a width direction of the intermediate transfer belt, through an opening portion disposed at a side face of the image forming apparatus, wherein the belt unit has a first roller supporting the intermediate transfer belt, a frame rotatably supporting the first roller, and a steering unit supported to be tiltable with respect to the frame and having a second roller supporting the intermediate transfer belt, the steering unit, in a case that the intermediate transfer belt moves to one side in the width direction thereof while the intermediate transfer belt rotates, being configured to tilt the second roller so that the intermediate transfer belt moves toward the other side thereof;
• a pair of first guided portions disposed at both ends of the frame with respect to the width direction of the intermediate transfer belt;
• a first guide portion disposed on the main body of the image forming apparatus and configured to support the pair of first guided portions when the belt unit is attached and to guide the frame;
• a pair of second guided portions disposed at both ends of the steering unit with respect to the width direction of the intermediate transfer belt;
• a second guide portion disposed on the main body of the image forming apparatus and configured to support the pair of the second guided portions when the belt unit is attached and to guide the steering unit,
• wherein the second guide portion releases support of the steering unit when the belt unit is positioned at an attached position.