Pneumatic rollers and paper handling arrangements

摘要

A roller assembly is provided with openings in its outer surface for selective communication with a source of vacuum or a positive pressure. The openings may be angled along the roller rotational axis to impart a component of velocity to the paper perpendicular to the tangential roller surface velocity. Additionally, by selectively connecting the openings with sources of pressure and vacuum, enhanced paper alignment is achieved, multiple paper feeds eliminated, transitions between different velocities of rollers completed, or paper reverted so that printing can be achieved on first and second sides thereof.