Abstract: A bidirectional document tractor unit having spaced apart laterally adjustable tractor mechanisms each provided with an endless tractor belt which is in driving engagement with a document support belt to provide a document path interposed between the support belt and the tractor belt. The support belts include perforations engageable with the drive pins on the tractor belt. The support belts also are drivably engaged with sprocket members having document drive pins formed thereon. The tractor belts are driven through suitable sprockets in driving engagement with an elongated driveshaft. Movable gates are disposed adjacent to the drive sprockets which provide for lead-in driving engagement with the document which is trained along the tractor belt between the tractor belt and the support belt, then through the printer platen and then along the opposite run of the tractor belts before returning to a document magazine or stack.