Delivery of a machine for processing flat printing materials

A machine for processing sheets in a processing direction, comprising:

• a delivery;
• a sheet guide surface having a given width;
• a conveyor for pulling the sheets over said sheet guide surface;
• nozzles opening into said sheet guide surface;
• a blown air supply for communicating with said nozzles;
• a blower disposed above said sheet guide surface to form a blown air curtain extending over said sheet guide surface transversely with respect to the processing direction, aimed at a target region on said sheet guide surface, and resulting in deflection of at least one part of flow, by said sheet guide surface, downline with reference to the processing direction;
• and
• said nozzles forming a first and a second group of nozzles, said first group being arranged on said sheet guide surface in accordance with a first mode and said second group being arranged on said sheet guide surface in accordance with a second mode, said nozzles of said first group outputting during operation a flow counteracting said deflected part of flow.