| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of promptly eliminating a deviation between a belt member and a second toner image carrier in a conveyance direction even when a sudden deviation more than a 1/2 scale pitch is generated, thereby maintaining high accuracy of superimposing a first toner image and a second toner image. <P>SOLUTION: In the vicinity of a transfer position of a second toner image, a magnetic reading head 18 detects a first scale 33 and generates a first signal, and a magnetic reading head 15 detects a second scale 32 and generates a second signal. A rotation control part 24 controls a photosensitive drum 42 so as to eliminate a phase difference between the first signal and the second signal. An exposure control part 21 starts formations of the first scale 31 and the second scale 32 with a second pitch greater than a first pitch which regulates accuracy of superimposing a first toner image and the second toner image. The formations of the first scale 31 and the second scale 32 with the first pitch are started after the phase difference between the first scale 33 and the second scale 32 is less than 1/2 of the first pitch. <P>COPYRIGHT: (C)2013,JPO&INPIT |
