| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a tandem type multicolor image forming device by which the internal part of the device is simplified and the image forming of a job where color image data are mixed with monochromatic image data is efficiently performed in a short time without increasing a cost and also to provide a multicolor image forming method. <P>SOLUTION: The device is provided with an image forming mode changeover means which performs changeover between a first image forming mode to allow whole photoreceptor drums to be brought into contact with a carrier belt when a color image is formed and a second image forming mode to allow only the most upper stream side photoreceptor drum to be brought into contact with the carrier belt in the case of monochromatic image forming. When monochromatic image data are mixed with multicolor image data in the image forming job consisting of a plurality of sheets, image forming mode changeover times are detected based on the co-existing state and image forming by combining the first and second image forming modes is selected when a total image data changeover times are equal to or less than prescribed times. When the total times exceed the prescribed times, the first image forming mode is selected for image forming. <P>COPYRIGHT: (C)2003,JPO |
