DEVICE FOR THE SMOOTHENING SHEETS AT THE IMPRESSION CYLINDER IN A SHEET-FED ROTARY PRINTING MACHINE

摘要

The continuation patent application describes a device for the smooth application of sheets (1) to be printed on an impression cylinder (3) in front of the nip (5) in a sheet-fed rotary offset printing machine, whereby there is provided a sword nozzle (8) being directable onto the circumference of the impression cylinder (3) and extending over an essential part of the width of the impression cylinder (3) for pressing down the sheet (1) to be printed through the effect of force of an air stream. This sword nozzle (8), at a distance in front of the nip (5), is mounted so as to be swingable around a pendulum axis (9) being positioned parallel to the axis of the impression cylinder (3) and is connectable with a drive which moves the sword nozzle (8) in running direction of the sheet (1) to be printed forth and back in a swinging manner, in phase with the machine. As compared to the main patent, the sword nozzle (8) has a shape, whereby the ends are offset with respect to a center range in running direction of the sheet, so that a smoothening of the sheet (1) to be printed takes place advancing in the center from the sheet front edge to the sheet trailing edge and from the sheet center to both sides. Preferred is a sword nozzle (8) having the shape of an arrow with its point directed against the running direction of the sheet (1) to be printed.