PURPOSE: To provide an image forming device which prevents excessive current from flowing into a backup roll from a bias roll and ensures steady transfer.
CONSTITUTION: The device is equipped with a latent image carrier 1, an intermediate transfer body 2, the bias roll 10, and the backup roll 4 arranged opposite the bias roll 10. The backup roll 4 comprises a roll main body and a covering layer, one of which is made of a conductive or semiconductive material and the other of which is made of an insulated or semiconductive material. Either the roll main body or the covering layer is gounded. The bias roll 10 is provided with a resistance detection means 17 which finds the resistance of the backup roll 4 by detecting a current flowing through the intermediate transfer body 2 and the backup roll 4 from the bias roll 10. The resistance detection means 17 is provided with a control means 18, which determines an optimum transfer voltage for the bias roll 4 and controls the power source of the bias roll 4 so as to apply this voltage to the bias roll 4.
FUKUDA YUICHI
HANDA OSAMU
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