| 摘要 |
PROBLEM TO BE SOLVED: To prevent the distortion of an electrostatic latent image formed on a photoreceptor belt by an optical writing means by preventing the inclination of the photoreceptor belt with respect to the optical writing means, at the time of driving the belt. SOLUTION: Supporting parts 31 projected at positions corresponding to the rotary shafts 1a of a driving roller 1 respectively are integrally formed to the case 8b of a developing unit 8. One rotary shaft 1a in which a driving gear 12 is arranged is inserted into one bearing groove 31a to be supported. On the other hand, the other rotary shaft 1a is inserted into the other bearing groove 31a to be supported. In the driving gear 12, reaction force F corresponding to the rotational load of the driving roller 1 is generated at a contact point M with a transmission gear 21. This reaction force F is exerted in the couple of force direction of torque transmitted from the transmission gear 21, on the tangent of the driving roller 1 and the transmission gear 21. One supporting part 31 is formed at a position shifted from the other supporting part 31 by a fixed offset length in a direction opposite to the reaction force F. |
