| 摘要 |
PURPOSE:To prevent the occurrence of a deviation in the superimposing of color caused by the eccentricity of a roller by setting the peripheral length of a roller having a high friction coefficient, out of rollers whose diameters are different, about the reciprocal-of-an-integer multiple of the peripheral length of a belt. CONSTITUTION:An intermediate transfer belt 39 is supported by a driving roller 42, a backup roller 44, and supporting rollers 52 and 53, which have different diameters, and has tensile force. The driving roller 42 and the backup roller 44 are made of a material so as to make the coefficient of friction with the belt 39 high, for driving the intermediate transfer belt 39 without sliding. Therefore, uniform presscontact with a recording paper 45 is obtained, and a transfer time in a nipping part is gained. Then, the peripheral length of the driving roller 42 and the backup roller 44 is set the reciprocal-of-an-integer multiple of the peripheral length of the intermediate transfer belt 39. Thus, in the deviation in the sending of the belt, generated by the eccentricity of the roller, that is, the deviation in the superimposing of the color, can be hardly generated, because the phase of the deviation in a position is reproduced every round. |
