| 摘要 |
PURPOSE: To provide a color image forming device capable of preventing color slurring without improving dimension and attachment accuracy in an image carrying belt and a driving roll, even if thermal expansion and shrinkage occur, with suppression of increase in the cost. CONSTITUTION: The color image forming device is composed of a belt reference position detecting sensor 22 detecting the reference position of an intermediate transfer belt 15, an encoder 17A detecting the reference position of the driving roll 17, a phase shift detecting part 36 detecting a phase shift in the rotational positions of the intermediate transfer belt 15 and the driving roll 17, based on detection timing at both detected reference positions, a belt tensile force correcting value calculating part 37 calculating the tensile force correcting value of the transfer belt 15 based on the phase shift and a belt tensile force imparting device control part 38 actuating the belt tensile force imparting device 27 in accordance with the calculated tensile force correcting value. |
