US Patent 7177562 Transfer power supply apparatus of an image forming machine

An apparatus for applying a voltage across an image carrying member carrying a toner image and a print medium, the toner image being transferred from the image carrying member to the print medium during an image transfer process. The apparatus includes a first voltage receiver disposed on a first side in reference to the print medium, a second voltage receiver disposed on a second side opposite the first side, a voltage supply unit adapted to apply the voltage selectively to the first voltage receiver and to the second voltage receiver, and a voltage adjustment unit adapted to compensate for variations of the voltage.