| CPC G03G 15/1615 (2013.01) | 20 Claims |
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1. A transfer device, comprising:
a plurality of rollers including a first roller, a second roller and a third roller;
an intermediate transferor to rotate in a rotation direction, wherein the intermediate transferor is stretched by the plurality of rollers, the first roller is upstream of the second roller and the third roller, and the second roller is upstream of the third roller;
a plurality of primary transfer sections to transfer developer images to the intermediate transferor, the plurality of primary transfer sections each including a primary transferor, and the plurality of primary transfer sections are disposed between the first roller and the second roller;
a tension roller which is a driven roller to stretch the intermediate transferor, the tension roller being downstream from a most-downstream primary transferor of a most-downstream primary transfer section of the plurality of primary transfer sections in the rotation direction;
a first movement motor to move the tension roller and change a position at which the tension roller stretches the intermediate transferor; and
a second movement motor to move a first primary transferor, of a first primary transfer section upstream from the most-downstream primary transfer section in the rotation direction, between a first contact position and a first separation position, the first contact position being at which the primary transferor contacts a latent image bearer with the intermediate transferor interposed between the first primary transferor and the latent image bearer, and the first separation position being at which the primary transferor is separated from the latent image bearer, wherein
the third roller forms a secondary transfer section,
the most-downstream primary transferor is movable between a second contact position and a second separation position, the second contact position being at which the most-downstream primary transferor contacts with another latent image bearer with the intermediate transferor interposed between the most-downstream primary transferor and the another latent image bearer, and the second separation position at which the most-downstream primary transferor is separated from the another latent image bearer, and
the first movement motor moves the tension roller between at least three positions at each of which the tension roller stretches the intermediate transferor, the at least three positions including:
a first position at which the most-downstream primary transferor is in contact with the intermediate transferor for image transfer in a first image transfer mode,
a second position at which the most-downstream primary transferor is positioned a first distance away from the intermediate transferor for image transfer in a second image transfer mode, and
a third position at which the most-downstream primary transferor is positioned a second distance away from the intermediate transferor for image transfer in a third image transfer mode, the second distance being larger than the first distance.
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