| 摘要 |
PURPOSE:To stably secure gaps between developing sleeves and a photosensitive body with high accuracy, to eliminate the complicated adjustment of the gaps, and to attain assembling only with inexpensive parts by abutting development backup members on the rear surface of a belt-like photosensitive body. CONSTITUTION:A belt 1 on which the belt-like photosensitive body is applied is disposed between turnable rollers 2 and 3 and carried clockwise in a tension state by the drive of the turnable roller 2. Four roller-like development backup members 40 are rubbed on the inner periphery of the belt 1. The development backup members 40 are oppositely arranged on four developing units 8-11 installed in the vicinity of the outer periphery of the belt-like photosensitive body, respectively. On the other hand, the belt-like photosensitive body on the outer periphery of the belt 1 is always kept at the position of constant relation with the surface of the development backup member 40, during carrying. Then, the outer peripheries of the bearing members of the developing sleeves 8A-11A of the developing units 8-11 are directly pressed on the development backup member 40, so that the gaps between the belt-like photosensitive body and the developing sleeves 8A-11A are kept constant. |
