An air assisted sheet guide device in a printing machine which is operable
during either positive pressure (blast) air operation as well as suction
air operation to permit reliable and stable sheet guidance with reduced
air flow turbulence. The sheet guide device includes at least one module
that defines a guide surface having air flow openings therein and an air
flow channel, and a pneumatic system for creating either a positive or
suction pressure generated air flow in the flow channel. One or more
plate-like air directional elements are mounted within the air flow
channel which create a uniform pressure distribution on the guide surface
during positive (blast) air operation and which more uniformly direct air
to the pneumatic system during suction pressure operation.
