| 摘要 |
The present invention relates to a color image forming device for forming toner images of a plurality of colors on a medium, and is for improving second transfer efficiency from an intermediate transfer body to the medium. The device has image forming units ( 12 - 1 to 12 - 4 ) for forming the toner images of the plurality of colors on at least one image bearing body ( 14 - 1 to 14 - 4 ) by a plurality of developing units ( 22 - 1 to 22 - 4 ) respectively accommodating toner of different colors; an intermediate transfer body ( 24 ); primary transfer means ( 38 - 1 to 38 - 4 ) for primary transferring the toner images of the plurality of colors onto the intermediate transfer body sequentially for the respective colors; and secondary transfer means ( 45 ) for secondary transferring the toner images of the plurality of colors on the intermediate transfer body onto the medium. The image forming units form the toner images of the plurality of colors so that the potentials of toner layers transferred onto the intermediate transfer body ( 24 ) are progressively lower in the order in which the plurality of colors are transferred. Since the potential of the toner layer directly adhered to the intermediate transfer body is higher, the directly adhered toner layer becomes easier to be secondary-transferred, and thereby, the secondary transfer efficiency is improved and the reproducibility of the secondary color is improved.
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