| 摘要 |
PROBLEM TO BE SOLVED: To restrain the deterioration of an image by keeping the load fluctuation of an image carrier to an endless belt constant and making the elongation of the endless belt or slide thereof to a driving roller small. SOLUTION: The tooth number of photoreceptor gears 18Y, 18M, 18C and 18B fixed on photoreceptors 3Y, 3M, 3C and 3B is different respectively and set so that it may be smaller in order toward the belt carrying direction of an intermediate transfer belt 2. Assuming that the surface speeds of the photoreceptors 3B, 3C, 3M and 3Y are V1, V2, V3 and V4 respectively, relation between the surface speeds holds V1<V2<V3<V4 because the diameters of the photoreceptors 3B, 3C, 3M and 3Y are the same. Assuming that the carrying speed of the belt 2 is Vb, the relation becomes Vb>V4, that is, Vb is higher than the surface speed V4 of the photoreceptor 3Y near to the driving roller 2B on the most downstream side in the belt carrying direction. |
