Forming web registration control system

A web registration control system for a movable web pre-printed with a series of registration marks and fed from a supply roll by an unwind motor, the system comprising:

• a framework on which the supply roll and unwind motor are mounted:
• a braking arrangement connected to the framework and selectively engageable with the web to stop the unwinding thereof;
• a photosensing mechanism located downstream from the braking arrangement on the framework for sensing a registration mark on the web, wherein the photosensing mechanism includes a pair of opposed, elongated, substantially parallel guide channels, one on either side of the web, one of the channels carrying a photoeye transmitting element and the other of the channels carrying a cooperating photoeye receiving element;
• and
• a heater system disposed downstream from the photosensing mechanism on the framework for selectively applying heat to the web upon the next registration mark downstream from the registration mark sensed at the photosensing mechanism.

A method of controlling registration of a web fed from a supply roll by a web advancement mechanism, the web having spaced registration marks, the method comprising the steps of:

• a) positioning a first heated area of the web upstream of the web advancement mechanism;
• b) operating the web advancement mechanism to apply a stretching force to the web at the first heated area while simultaneously stopping the web at a position upstream from the web advancement mechanism and the first heated area;
• c) subsequently heating the web at a second heated area upstream of the first heated area;
• and
• d) advancing the web by operation of the web advancement mechanism such that the first heated area is located downstream of the web advancement mechanism and the second heated area is located upstream of the web advancement mechanism whereby the second heated area is adapted to be stretched by operation of the web advancement mechanism while the web is stopped, at a location upstream of the web advancement mechanism.

A method of obtaining precise registration of a forming web in an indexing motion web advancement mechanism, the web having spaced registration marks, the method comprising the steps of:

• a) passing the web from a supply roll through a braking arrangement, a sensing mechanism for sensing the registration marks on the web and a heater system movable back and forth relative to the web to a nip roller arrangement having one or more driven rolls driven by the unwind motor, wherein the heater system is operable to create a first heated area of the web;
• b) indexing the web from the supply roll by operation of the unwind motor;
• c) sensing the presence of a first registration mark on the web upstream of the first heated area by the sensing mechanism;
• d) stopping the feeding of the web from the supply roll using the braking arrangement upon sensing of the first registration mark;
• e) stretching the web downstream of the heater system at the first heated area by continuing to operate the unwind motor to apply tension to the web;
• f) stopping the unwind motor when the web is stretched an amount sufficient to provide a desired spacing between a pair of registration marks which at least partially includes the first heated area;
• and
• g) applying heat to the web in a second heated area by moving the heater system towards the web upstream of the first heated area.

A web registration control system for a movable web imprinted with a series of variably spaced registration marks, wherein the space between adjacent registration marks is less than a predetermined spacing, comprising:

• an intermittently operable web advancement mechanism;
• a braking mechanism located upstream of the web advancement mechanism and selectively engageable with the web;
• a sensing mechanism located upstream of the web advancement mechanism;
• and
• a heating arrangement located upstream of the web advancement mechanism adjacent the web;
• wherein the heating arrangement is operable to provide a first heated area between the braking arrangement and the web advancement mechanism so that operation of the braking mechanism stops advancement of the web and simultaneous operation of the web advancement mechanism stretches the web at the first heated area, and wherein the web advancement mechanism is operable to provide a variable amount of stretch at the first heated area to enable the space between a pair of adjacent registration marks, which includes the first heated area, to substantially equal the predetermined spacing;
• and
• wherein the heating arrangement is operable to provide a second heated area upstream of the first heated area and the web advancement mechanism is operable to advance the first heated area after stretching past the web advancement mechanism to enable subsequent stretching of the web at the second heated area by operation of the braking mechanism and the web advancement mechanism.