Patent ID: 7035563

Claim:
An image forming device comprising: an image carrier which holds a toner image formed by developing; a contact transfer body which is arranged so as to contact with the image carrier; a transfer bias application device which applies a transfer bias to the contact transfer body for transferring the toner image on the image carrier to a recording element; a transfer body cleaning device which applies a transfer cleaning bias whose polarity is inverted from that of the transfer bias to the contact transfer body for performing a cleaning operation for a toner which is attached or remained on the contact transfer body, the transfer body cleaning device comprising: a transfer body resistance detecting section which detects and outputs a value of an electrical resistance of the contact transfer body; and a cleaning bias control section which changes an applying time of the transfer cleaning bias based on a detection output signal from the transfer body resistance detecting section, wherein the cleaning bias control section varies the applying time of the transfer cleaning bias based on a size judgment signal for the recording element in addition to based on the detection output signal from the transfer body resistance detecting section.