| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent staining of the back surface of printing paper caused by forced-out toner without lowering printing efficiency in an image forming apparatus. <P>SOLUTION: A toner image on a photoreceptor formed according to the image of an original is transferred to an intermediate transfer belt 10. The length of the printing paper is measured by a resist sensor 25 to decide whether or not the printing paper is the same size as the image. When deciding that their sizes are not the same, particularly, when the printing paper is shorter than the image, the toner image on the intermediate transfer belt 10 is transferred to the printing paper, and then a secondary transfer roller 11 is cleaned by the application of bias for reversely transferring toner on the secondary transfer roller 11 to the intermediate transfer belt 10. Since the back surface of the next sheet of printing paper is not stained even when the image is printed on the paper whose size is different from designated paper size, excellent printing is always performed. <P>COPYRIGHT: (C)2008,JPO&INPIT |
