| 摘要 |
<P>PROBLEM TO BE SOLVED: To make service life color printing photoreceptors longer and ensure quick start of printing, in an image forming apparatus. Ž<P>SOLUTION: The belt section 21 is stretched in a loop and moved in the direction of the loop. The image forming section 17 forms toner images of different colors on the surfaces of photoreceptors 17b to 17y. The displacing section 25 operates in a pressure-contact by which the photoreceptors 17b to 17y are brought into pressure-contact with the belt section 21 in order to transfer the toner images formed on the photoreceptors 17b to 17y to the belt section 21, and a separation by which the photoreceptors 17m to 17y used for only a color operation are separated from the belt section 21. An operation period obtaining section 13a obtains a color operation cumulative period and the monochrome operation cumulative period of a monochrome operation. According to levels of the color operation cumulative period and the monochrome operation cumulative period, a displacement control section 13c controls the displacing section 25 to be operated in the pressure-contact or the separation. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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