| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent printing fogging and the retransfer of a toner image in a black image forming unit. <P>SOLUTION: The 1st to the 4th image forming units UC, UY, UM and UBk respectively forming cyan, yellow, magenta and black color toner images are disposed in order from an upstream side to a downstream side in the rotating direction of a carrying belt 5 carrying transfer material P on its surface and rotating in a direction shown by an arrow A. The respective color toner images formed on the photoreceptor drums 10C, 10Y, 10M and 10Bk of the respective image forming units are successively transferred and superposed on the transfer material P. At such a time, the potential by electrification of the drum 10Bk for black is set to be lower than that of the drums 10C, 10Y and 10Bk for other three colors. Thus, the printing fogging and the retransfer of the toner image in terms of black are prevented. <P>COPYRIGHT: (C)2003,JPO |
