| 摘要 |
PROBLEM TO BE SOLVED: To prevent irregular image from occurring caused by the rotation irregularity of a photoreceptor drum by providing a roller brought into contact with a rolling surface formed on the photoreceptor drum having a common axis with the rotary shaft of a small-diameter gear. SOLUTION: A roller 46 is fitted to a driving shaft 42 supported by bearings 47a and 47b through a bearing 46 adjacently to the small-diameter gear for driving 41. The roller 46 is provided in order to prevent the shaft 42 from being deflected in a direction that backlash is increased when an inner gear part 31a is driven by the gear 41. Then, the outside circumferential surface of the roller 46 abuts on a circular-arc surface 38a formed on a photoreceptor unit frame 38 with the rotary shaft 35 as a center. Since the supporting position of the shaft 42 approaches the gear 41 by providing the shaft 42 with the roller 46, the backlash between the gear 41 and the gear part 31a is hardly changed from a prescribed value at the driving time. That means, since the backlash is hardly generated, the rotation irregularity is not caused and the gear part 31a is smoothly driven by the gear 41. |
