Abstract: The invention relates to a method of guiding a web of paper or foil material in a web-guiding device, such web having print marks applied to it at least over stretches of the web, as well as to such a web-guiding device with a correcting device, the latter being adjustable when the center of the web runs off course and with a controlling system connected to an edge-sensing system, whereby the position of the print marks relative to an imaginary guide line is controllable over stretches of the web carrying print marks, and additional correction relating to the latter can be made, if required. According to the invention, print marks signals are produced by means of a print mark sensor and linked with the correction signals of the edge-sensing system, with priority of the print mark signals.

Abstract: An assembly at an extruder for controlling the width of a two-layer web flattened from a tube extruded from a rotating or oscillating head of the extruder comprises monitors for detecting the velocity and edge-positions of the web upon transport thereof away from the extruder. A control circuit calculates the deviation of the actual web width from a predetermined width and emits a correction signal relayed via a stationary infrared-radiation transmitter and a receiver on the extruder head to valves controlling the pressurization of the extruded tube by a blower also mounted on the extruder head.