Patent ID: 6886310

Claim:
A method of forming reclosable packaging bags using a continuously traveling film fitted with at least one closure tape ( 60 ), which extends transversely to a longitudinal travel direction of the film, wherein the method comprises; cyclically sealing the film with a set of heat-sealing jaws ( 30 ) provided transversely relative to the travel direction of the film ( 12 ); detecting a default in position of the tape ( 60 ) on the film by means of at least one sensor ( 100 ) provided in a predetermined position relative to said heat-sealing jaws; and repositioning the film correctly in relation to the heat-sealing jaws when the sensor detects a default in the position of the tape, so as to eliminate drift due to the elasticity of the film, wherein the sensor comprises dual feelers that are juxtaposed in the longitudinal travel direction of the film, and wherein the repositioning is by repositioning means responsive to the detection of the default in the position of the tape by the at least sensor.