Sheet guiding device for printing presses

A sheet guiding device for guiding sheets in a printing press, comprising:

• a guide surface member having a guide surface;
• said guide surface having blast air or suction slit nozzles formed therein, said nozzles directed crosswise to a sheet travel path;
• said guide surface member being formed successively of an entry region, a guide zone and an exit region as viewed in a sheet transport direction;
• air supply chests for supplying air to respective regions of said guide surface member, and respective fans assigned to said air supply chests, said air supply chests, respectively, having a size adapted for air requirements at said respective regions and said air supply chests acting selectively in individual regions;
• said nozzles in said guide zone supplying blast air and said nozzles in said entry region and said exit region supplying blast air if the printing press is operating in a perfector mode for preventing the sheets from contacting said guide surface;
• said nozzles in at least one of said entry and said exit regions supplying suction air if the press is operating in a recto printing mode for providing frictional forces between the sheets and said guide surface member;
• and
• at least some of said nozzles emitting blast air substantially tangentially to said guide surface, said nozzles disposed on said guide surface in an array having a distribution varying in density and said distribution density of said nozzles is greatest in a middle of the travel path for the sheets and decreases towards an edge of the sheet travel path.