Abstract: An electrostatic charge is applied to a dielectric peripheral surface of a transfer drum and a copy sheet is fed between the transfer drum and a photoconductive drum to transfer a toner image from the photoconductive drum to the copy sheet. The drums rotate at the same surface speed and in the same direction at adjacent portions thereof. The surface speed is maintained at a first value for a first toner transfer operation and then changed to a second value for a subsequent toner transfer operation. A voltage sensor in combination with a variable voltage source adjusts the value of the electrostatic charge on the transfer drum to a predetermined value at either surface speed.