Duplexing in automatic document feeder utilizing a path shorter than the length of the document to be duplexed

The footprint of a document scanning unit such as a copier, facsimile machine or document scanner or combinations thereof is reduced by causing overlap of the leading and trailing edges of long document sheets to be scanned in the document delivery roller system downstream of the scanning system (40). Differential slippage of the overlapping ends between a drive roller (54) and a pinch roller (52) is provided in a first embodiment. A second embodiment uses a moveable pinch roller (64) in the document delivery system to selectively open and close a gap to permit slippage of the leading and trailing edges of the document. A third embodiment uses three document delivery rollers (72, 74, 76) defining two spaced nips in which the leading and trailing edges of a long document are simultaneously present and a crenellated roller surface to guide the leading edge of the document to the desired nip in the delivery system (70).