| 摘要 |
PROBLEM TO BE SOLVED: To prevent the deviation of an image forming position for a recording sheet while preventing the useless consumption of a photoreceptor drum or the like with respect to a tandem type image forming device. SOLUTION: When a monochrome mode is set from a state beeing in a color mode as shown in a figure, a rocking frame 53 is rocked in a clockwise direction around the shaft center of a driven roller 56, so that a carrying belt 51 is separated from other photoreceptor drums 48c-48Y excluding the photoreceptor drum 48K for black image formation. By this separating operation, the starting timing of exposure scanning for the photoreceptor drum 48K is delayed in the monochrome mode by a portion where the carrying path length of the recording sheet reaching from a timing roller 45 to the transfer position of the photoreceptor drum 48K is made long. |
