Folie oder Bahn mit Markierungspunkten

1,222,057. Perforating by burning. CONSOLIDATED PAPER (BAHAMAS) Ltd. 1 'April, 1969 [9 April, 1968], No. 17018/69. Heading B4B. A moving web or sheet of material 1 is measured by accurately spacing a reference mark sensing-station 25 downstream of a reference mark forming-station 17, forming a first reference mark 3 at the station 17 by electrically perforating the web 1 as it passes through the station 17, sensing the first mark 3 as the web passes through the sensing station 25, actuating the forming-station 17 on sensing the first mark 3 to produce a second reference mark 3, continuing the procedure to form a series of spaced reference marks 3, and counting the number of marks 3. Preferably, marks 3 invisible to the naked eye but detectable by optical means, including a light source 18 and photomultiplier (29), Fig. 4 (not shown), are produced, e.g. in a paper web 1, by spark dixcharge between electrodes 7, 9, or by means of a laser beam, and specific patterns of holes may be formed, e.g. to reproduce coded information.