초록 ▼

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 veloc

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.

대표청구항 ▼

[ Having thus described the invention, it is now claimed:] [6.] A roller assembly for processing sheet material in a printing apparatus, the roller assembly comprising:a first roller having an external surface with a series of openings communicating with a plenum in the first roller, the plenum bein

[ Having thus described the invention, it is now claimed:] [6.] A roller assembly for processing sheet material in a printing apparatus, the roller assembly comprising:a first roller having an external surface with a series of openings communicating with a plenum in the first roller, the plenum being in selective communication with a vacuum source and a pressure source for urging a sheet material toward and away from the external surface, respectively, as the first roller rotates, wherein the first roller is selectively connected to the vacuum source and the pressure source during predetermined rotational positions of the first roller as the sheet material traverses and leaves, respectively, the external surface thereof; anda second roller disposed downstream from the first roller for receiving the sheet material from the first roller, wherein the second roller is selectively connected to the pressure source and the vacuum source during predetermined rotational positions of the second roller as the sheet material approaches and traverses, respectively, the external surface thereof.