Device for achieving a flat contact of stocks or printing materials

Device for achieving a flat contact of stock on a curved surface of a cylinder for transporting the stock into a printing nip, comprising a plurality of blowing-air bars disposed in a region between an impression cylinder and a transfer drum and upstream of the printing nip in transport direction of the stock, said blowing-air bars being directed for blowing air in a direction opposing the transport direction of the stock, at least one of said plurality of blowing-air bars being stationary and at least one of said plurality of blowing-air bars being adjustable, said blowing-air bars each having a plurality of air-blowing nozzle-shaped outlets formed in a substantially arrow-shaped arrangement on the respective circumferences thereof, said arrangement of outlets including a central outlet disposed farthest upstream of said arrangement of outlets in the transport direction so as to be a first one of said outlets to act upon a sheet being transported in the transport direction, and adjusting means for varying a working position of said adjustable blowing-air bar between predetermined working positions depending on a grade of stock to be processed;

• wherein, starting from said central outlet and extending towards the ends of the respective blowing-air bars, respective pairs of said outlets, of which each outlet of a respective pair thereof is located on opposite sides of said central outlet, are formed with outlet openings having cross sections which increase towards said ends of said blowing-air bar.