| 摘要 |
PROBLEM TO BE SOLVED: To prevent the wear and tear of the image carrier of an image forming means for forming a color image in the case of forming a monochromatic image by switching the formation of the color image and the formation of the monochromatic image. SOLUTION: In the case of forming the color image, respective color toner images are respectively transferred to an intermediate transfer belt 20 by the image forming means 14, 15, 16 and 17. In the case of forming the monochromatic image, a pressing roller 31 presses the surface of the belt 20 by a pressing mechanism 32 so as to change a circulating path so that the belt 20 may come into contact only with the image carrier 30 of the image forming part 17 for forming a black toner image. Since the image carriers 30 of the image forming parts 14, 15 and 16 which are not used do not come into contact with the belt 20, their wear and tear is avoided. The roller 31 is arranged on the downstream side of a cleaning unit 27 with respect to the circulating path of the belt 20 and presses the belt 20 from the outside of the circulating path. |
