A device for conveying sheets through a printing machine which ensures the safe transport of the sheet exactly in the prescribed transport path, at a low material expense. In particular, an individual can submit a check to a check casher entity, in exchange for a stored-value card with an associated pending deposit to be made available on a specified date. A first middle point is calculated based on the detected first and second markers and a second middle point is calculated based on the first middle point and a difference in direction between a reference direction and a direction from the first detected marker to the second detected marker.