Patent attributes
An image forming apparatus of the present invention attaches a process unit to a body frame, thereby fits a third coupling into a second coupling of a drive transfer device, forms the Oldham structure, absorbs a shift between axial centers of a belt side shaft and a belt drive shaft, and always presses the second coupling toward the third coupling by a coil spring, absorbs a shift in the parallel direction with a belt side shaft 32a, thereby surely fits the third coupling into the second coupling, even if the axial center of the belt side shaft is shifted from the axial center of the belt drive shaft due to distortion of the unit, rotates stably the transfer belt, causes no distortion to a transfer image, and obtains high color superimposition precision.
