| 摘要 |
<P>PROBLEM TO BE SOLVED: To shorten a period of time required for black monochrome image formation in a tandem type of image forming apparatus. <P>SOLUTION: When a color image formation is carried out, a black image forming unit 30BK is moved to a position where a photoreceptor 1BK faces a transfer roller 6BK. When a black monochrome image formation is carried out, the unit 30BK is moved to a position as shown in Fig. 2. Also, when the color image formation is carried out, a transfer roller 7 is disposed in a position where the transfer roller 7 is opposite a backup roller 33 in contact with an intermediate transfer belt 31. When the black monochrome image formation is carried out, the transfer roller 7 is disposed in contact with the photoreceptor 1BK as shown in Fig. 2. During the black monochrome image formation, a toner image on the photoreceptor 1BK is directly transferred to a transfer material P with the transfer roller 7 without using the intermediate transfer belt 31. <P>COPYRIGHT: (C)2003,JPO |
