The invention relates to the reciprocating folders (6) used in packaging machines, packing machines and the like, particularly in cellophane wrapping machines, for folding on one side (103) of an article (3) to be packaged an edge (104) of a sheet (4) or slip of wrapping material, particularly of a material which is not much rigid and/or is easily charged with statical electricity. According to the invention, for preventing the folder (6) from dragging along, during its return stroke, the folded edge (104) of the sheet (4) or slip, one or more blowing nozzles (9, 109) are provided, and are oriented and arranged in such a manner that an air layer is generated between the folder (6) and the folded edge (104) of the sheet (4) or slip.