Roller, belt unit, and image forming apparatus that uses a roller and a belt unit

摘要

A belt unit for use in an image forming apparatus includes a first roller driven by a drive source in rotation and a second roller having a circumferential surface covered with a resin material. An endless belt is entrained about the first and second rollers. When the first roller rotates, the endless belt runs about the first roller and the second roller. The second roller includes segments that can be assembled together so that the segments can rotate together about a same rotational axis. The at least one of the plurality of rollers is a driven roller that is not coupled to the drive source. Each segment is a molded hollow cylinder having an axial length shorter than 150 mm. Each segment has an inner hollow cylinder through which a shaft extends. The second roller may be rotatable relative to the shaft or together with the shaft.