| 摘要 |
PURPOSE:To prevent occurrence of contact or collision of a joint part and a picture forming means and prevent occurrence of deviation of picture position of a belt and falling down of toner from the belt by making the picture forming means take refuge when a joint part passes through a picture forming part. CONSTITUTION:Normally, a developing device 30 is deviated in counterclockwise direction by repulsive force of a spring 45, and a developing roller 31 is stopped opposite to a belt 9 keeping a specified small space (d). When a thick joint 18 of the belt 9 arrives at a developing section, a roller 23 of chain 14 side comes into contact with the central part 56a of a rail 56 and pushes down the rail. Linking with this movement, the developing device 30 turns clockwise around a fixed axis 44, and the developing roller 31 is kept away from an exposing roller 29. Then, with running of the belt 9, the roller 23 comes into contact with a slope 56b. On the other hand, a roller 22 comes into contact with the center 56a, and accordingly, the space between the developing roller 31 and an exposing roller 29 is maintained sufficiently large until the thick joint part 18c passes. Thus, as impact force to the developing device is small, positional accuracy of the developing roller 31 is improved, and as descending of the developing device is smooth, scattering of toner from the developing device is reduced. |
