Patent ID: 7860429

Claim:
A cleaning device, comprising: a plurality of brush rolls being in contact with a surface of an image carrier to which a toner is attached, wherein the image carrier is an intermediate transfer unit; and a biasing unit applying bias voltages having different polarities from each other to at least two of the brush rolls; wherein the cleaning device is configured to be disposed to face a tension roll; and the plurality of brush rolls including a first brush roll and a second brush roll, a bias having a polarity opposite to a normal polarity of the toner being applied to the first brush roll, a bias having the same polarity as the normal polarity of the toner being applied to the second brush roll, and a surface circulating speed of the first brush roll being set to be higher than the surface circulating speed of the second brush roll; wherein a direction of rotation of each of the plurality of brush rolls is opposite to a direction of rotation of the image carrier; a speed of the first brush is no fewer than 0.5 times, and no more than 1.5 times of a speed of the image carrier; and a speed of the second brush is no fewer than 0.05 times, and no more than 0.5 times of the speed of the image carrier.