DEVICE FORMING PLURAL TONER IMAGES MUTUALLY REGISTERED ON BASE MATERIAL

PROBLEM TO BE SOLVED: To provide an image forming device by which specified belt speed is surely secured. SOLUTION: An endless belt 26 is passed through an imaging part 29, developing parts 35, 36, 37 and 38 and transfer parts 40, 41, 42 and 43 along a belt path 58 by a belt driving device 56 capable of being controlled. A sheet-like base material 78 is sent along a base material path 17 so as to synchronize and to be brought into contact with the endless belt 26 at the transfer parts 40, 41, 42 and 43 by a base material driving part 76 capable of being controlled. A preliminarily forming timing mark 44 is added to the belt 26, and the passing of the timing mark 44 is detected on the rear side of a detection position 48 by a sensor 49. A controller 50 controls the belt driving device 56 so as to control the speed of the belt 26 in response to the detection of the timing mark 44 by running the belt driving device 56 by specified speed.