| 摘要 |
PROBLEM TO BE SOLVED: To select a monochrome image forming mode and a multicolor image forming mode without using a mechanically complicated mode switching means and to save the needless operation of a multicolor image forming unit which does not participate in image forming process in the monochrome image forming mode so as to prolong the life of the image carrier of the multicolor image forming unit and reduce running cost. SOLUTION: In this multicolor image forming device, a monochrome image forming unit 110K is provided independently of the multicolor image forming units 110Y, 110M and 110C, and the multicolor image forming unit and the monochrome image forming unit are driven at the time of forming a multicolor image, and only the monochrome image forming unit is driven at the time of forming a monochrome image. Thus, the prolongation of the lives of the multicolor image forming unit and the photoreceptor drums 1Y, 1M and 1C thereof at the time of forming the monochrome image (improvement of durability), the reduction of the running cost (energy saving) and the prevention of noise at the time of driving the device are realized. Since the respective image forming units can be selectively and independently driven without using the mechanically complicated mode switching means, the complication of the control and the structure of the device is restrained.
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