Ishii Akihiko

Conductive roller transfer device with improved transfer efficiency and pollution control

A toner image transferring device has a roller formed of a conductive rubber foam material having a resistivity of more than 107 Ωcm. In a toner image transferring process, a constant current is applied to the roller, whereby a charged toner image can be transferred to a sheet or paper at a desired toner transfer efficiency regardless of a size of the paper or sheet. To remove a toner pollution of the roller, a constant voltage having a polarity opposite to that of the charged toner is applied to the roller. The roller is constituted such that pore openings appear over a surface of the roller, whereby a residual part of a toner polluting the roller will not leave a stain on a rear surface of the sheet or paper.