| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that prevents failure when switching between image modes, even when the image modes are mixedly loaded, and that improves the life duration and productivity of an image forming unit. <P>SOLUTION: An image forming apparatus includes: a color image forming unit 12a-12c having a color toner; a black image forming unit 12e having a black toner; a heterogenous toner image forming unit 12d having a heterogenous toner; a contacting and separating device 60; and controlling means 70. The contacting and separating device 60 carries out a first separating operation for separating the color image forming unit and the heterogenous toner image forming unit from an intermediate transfer belt 7, and a second separating operation for separating the color image forming unit from the intermediate transfer belt. When shifting from a 5 color mode to a black color mode or to a special monochrome mode which uses the black toner and the heterogenous toner, the controlling means 70 controls an operation of the contacting and separating device 60 according to the number of pages to be printed in a post-shifting mode, and if the number of pages to be printed in the post-shifting mode is low, printing is performed in the post-shifting mode without carrying out the first or the second separating operation. <P>COPYRIGHT: (C)2012,JPO&INPIT |
