Printing press for printing on sheets

The invention relates to a printing press for printing on a sheet (6), comprising two cylinders (1, 2) in the form of a counter-pressure cylinder (1) and a blanket cylinder (2), which together form a printing gap (3), in front of which a blowing device (11) is arranged. The counter-pressure cylinder (1) has a cylinder channel (4) and the blanket cylinder (2) has a tensioning channel (7). According to the invention, a sealing device (16) or a sealing device half is fastened to one of the cylinders (1, 2), said sealing device or sealing device half sealing the printing gap (3) when the tensioning channel (7) lies opposite the cylinder channel (4) and preventing the blowing device (11) from blowing gas through the printing gap (3). 本发明涉及一种用于在印张(6)上印刷的印刷机，其包括两个滚筒(1，2)，这两个滚筒呈对压滚筒(1)和橡皮布滚筒(2)的形式，它们共同形成印刷间隙(3)，在该印刷间隙前面设有喷吹装置(11)。所述对压滚筒(1)具有滚筒通道(4)并且所述橡皮布滚筒(2)具有张紧通道(7)。在所述滚筒(1，2)之一上固定有密封装置(16)或密封装置半部，所述密封装置或密封装置半部在所述张紧通道(7)与所述滚筒通道(4)对置时密封所述印刷间隙(3)并且防止所述喷吹装置(11)将气体吹过所述印刷间隙(3)。