| 摘要 |
PROBLEM TO BE SOLVED: To switch, even during a consecutive printing operation of an image forming device of a tandem type, a print mode depending on whether an original-document from which an image is to be formed has color or not and, therefore, to prevent unnecessary exhaustion of photoreceptor drums. SOLUTION: During a consecutive printing operation, an original-document judgment means judges whether a print mode for a recording sheet to be carried next is color or monochromatic one. In the case of the color print mode, a swing unit 821 is turned into a horizontal position. In the case of the monochromatic print mode, a plate cam 8291 is turned to swing a swing unit 821 downward around the shaft of a follower roller 824, and thus the photoreceptor drums 61IC-611Y which are not involved in image formation are separated from a carrying belt 81 and also the rotations of the photoreceptor drums 611C-611Y are stopped. The contact/separation is carried out before the image formation on the recording sheet to be carried next after image formation on a recording sheet carried previously. |
