Patent ID: 8301060

Claim:
An image forming apparatus comprising: an image formation device configured to form an image by transferring a plurality of colors of developers; an apparatus body including the image formation device and a supporting member; a belt unit configured to be attached to and removed from the apparatus body, the belt unit including: a drive roller and a non-drive roller spaced apart from each other; an endless belt extending around the drive roller and the non-drive roller, the endless belt being configured to face the image formation device and rotate in connection with an image formation operation of the image formation device when the belt unit is attached to the apparatus body; and a belt frame to which the drive roller and the non-drive roller are disposed; and a mark sensor configured to detect a registration mark on the endless belt, wherein the supporting member of the apparatus body includes: a first positioning portion and a second positioning portion opposed to the first positioning portion, the first and second positioning portions being configured to support and position the belt unit at a predetermined position in the apparatus body; and a connection portion configured to support the mark sensor thereon and integrally formed with the first and second positioning portions such that the connection portion connects the first and second positioning portions.