A cylinder on an offset printing press that replaces a conventional transfer cylinder, and is used for transporting printed sheets from the impression cylinder to either the delivery pile or to additional printing units in the press. A conventional transfer cylinder uses near-frictionless covers and coatings to ensure that the wet ink is not smudged or marked during transport. An air-transport drum (in some configurations) features a metal cylinder with a cover through which small jets of air can be pumped, providing a cushion of air on which the printed sheet can ride, preventing it from contacting any hard surface that can mark or smudge the ink. An air-transport drum is also known as an air-cushion drum.
|