A device for conveying sheets through a printing machine, in particular through an ink jet printing apparatus, permits adaptation to different printing material thicknesses and ensures reliable transport. The conveying device has a conveyor belt which runs over deflection rollers and guide elements and to which sheets can be fed individually one after another. An apparatus enables setting the distance between the surface to be printed of a sheet and a print head. At least three conveying segments are arranged one after another, the print head being fastened to a holding device opposite a central conveying segment. Each conveying segment is assigned at least one guide element and it is possible to adjust the height of the guide element opposite the print head in accordance with the thickness of the sheets.