Abstract: An improved backup roll for use in the heated fuser system of electrostatic copy machines wherein the fuser system employs a fuser roll couple comprised of a heated fuser roll in pressure contact with the backup roll. In construction, the backup roll includes an aluminum core member with a coating of polyurethane reinforced flourinated ethylene propylene on its surface. The coating has heat transfer characteristics similar to the copy sheets fed through the couple so as to withdraw heat from the heated fuser roll, along each zone where it may make direct contact with it, at substantially the same rate as the copy sheets withdraw heat. The coating also has a thickness whereby the heat transferred to each zone during contact with the fuser roll is quickly transferred to the aluminum core before that zone again contacts the fuser roll.

Abstract: A two cycle process electrophotographic copying device having charging, imaging, developing, transferring, and cleaning facilities, the arrangement being in the conventional sense, incorporates a combined charge and preclean corona unit that is operable to perform either a charging function or a precleaning function at the proper time during a copying/cleaning cycle and a combined precharge/transfer corona unit. The combined charge and preclean corona unit includes a dual bay corona which emits negative and positive ions and a common control grid for controlling the ion flow from each bay of the dual bay corona.