The sheet straightening device consists of a laying table and a stop in or across the sheet feed direction. It includes a pulse transmitting device consisting of a toothed belt (10) passed over a drive roller (8) and a diverting roller (9). The belt teeth (11) have a phase (14) at the side. The working surfaces of the teeth are curved, with a radius compatible with the centre point of the diverting roller. The drive roller and the diverting roller may be in the form of toothed discs, and the belt may have teeth on both sides.
