| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve the quality of a printed image in a both side image forming mode in a color image forming apparatus of an electrophotographic system. <P>SOLUTION: A plurality of image forming parts comprising photoreceptor drums and transfer rolls, etc., are provided corresponding to respective color toner images and toner images on photoreceptor drums 11 to 14 are transferred by transfer rolls 41 to 44 in the color image forming apparatus of the electrophotographic system. The rotational speed of each photoreceptor drum is controlled by a drum speed variation control part 31. At the same time, by maintaining the running speed of a transfer belt to be constant, Vb/Vd value when printing a back side of the paper (Vb is the surface speed of the transfer belt and Vd is the surface speed of the photoreceptor drum) is brought farther away from 1 compared with the Vb/Vd value when printing a front side of the paper. Thus, both the securing of high toner image transferring ratio in regard to the paper back side and suppressing of increase in color deviation in the sub-scanning direction can be achieved. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
