A system for providing duplex images on copy sheets wherein the images are formed on the copy sheets by delivering the sheets to an impression cylinder for transfer of the images to the sheets. First and second ink images are provided, and each sheet is fed to the impression cylinder in synchronism with a first image for transfer of the first image to one side of each sheet. Each sheet is then removed to a staging area which includes a conveyor mechanism for re-feeding the sheet to the impression cylinder, trailing edge first. The re-feeding is in synchronism with the movement of the second image whereby this second image is transferred to the opposite side of each sheet. The impression cylinder is provided with a first gripper for engaging the leading edge of each sheet and with a second gripper for engaging the trailing edge of each sheet. The staging area comprises a plurality of conveyor belts and a chamber with air exhaust means beneath the belts. Appropriate perforations are provided whereby evacuation of air from within the chamber and through the perforations holds the sheets in place on the conveyor belts. The belts move in one direction for feeding of the copy sheets into the staging area, and then reverse for re-feeding to the second gripper. Barrier means on the belts accurately align the sheets, and adjustable drive mechanisms accurately deliver the sheets to the impression cylinder.
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