Patent ID: 7801472
Filing Date: 2010-09-21
Classification: G03G

Abstract:
1. A device for simultaneous double-sided printing of a recording medium, comprising: a revolving first transfer belt and a revolving second transfer belt; a first toner image generator generating on the first transfer belt a first toner image comprising toner that is charged with a first polarity; a second toner image generator generating on the second transfer belt a second toner image comprising toner that is also charged with the first polarity; a charge shifting device which shifts the charge of the first toner image located on the first transfer belt to a second polarity which is opposite to the first polarity; a transfer printing region at which the recording medium is passed between the fist transfer belt and the second transfer belt and at which an electrical field is generated via which the first toner image shifted to the second polarity and the second toner image are separated from the first or second transfer belt respectively and are transferred to a respective side of the recording medium facing the respective transfer belt; a recharging device to recharge the second toner image located on the second transfer belt with the first polarity; and at least one of the charge shifting device and the recharging device comprising a corotron, an antipole element situated opposite the corotron at an opposite side of the transfer belt facing away from the corotron and forming an electrical antipole relative to a charge of the corotron, the antipole element being in contact with said opposite side of the transfer belt, and the corotron comprising at least one corona wire at which an alternating voltage is applied and a shield at which a direct voltage is applied.