Picture forming device

Abstract

Abstract PURPOSE:To prevent an offset by utilizing an attracting or repulsing force between a toner and a roller, by applying the bias voltage whose polarity is opposite to charge of an unfixated toner of a fixating side, to a roller of the side which does not contact with a toner image. CONSTITUTION:A pressure roller 4 is grounded through a bias electric power source 20, and a fixing roller 1 is grounded. When copying both faces, the power source 20 applies voltage whose polarity is opposite to a toner T2 fixated to an image supporting material contacting with the roller 1. In this case, the bias whose polarity is opposite to a toner T1 is applied to the roller 4. The face of the toner T1 of the supporting material of the side where a copying process is completed is charged electrostatically to the opposite polarity to tribo of the toner by the transfer process. The toner T1 and the roller 4 have the same polarity, repulse each other, and prevent an offset phenomenon. Also, since charge of the toner T2 of the roller 1 side is opposite in polarity to charge of the roller 4, said roller and the roller 4 drawn each other through the supporting material, therefore, the releasability of the roller 1 and the toner T2 increases, and an offset to the roller 1 is extremely reduced.

Inventors

• 👤 Shigetatsu Washiyama
• 👤 鷲山　成達

Bibliographic Details