Abstract: A corrugator line includes a single facer and a double backer with a horizontal bridge extending between them. Instead of conducting the web from the single facer to the double backer as fan folds on a horizontal belt conveyor, a dancer type accumulator is positioned on the bridge between the single facer and the double backer and the web is looped back and forth between the accumulator stationary rollers and its movable dancer and the dancer is force loaded away from the stationary rollers so as to maintain substantially constant tension in the moving web. Provision is made for controlling the speed of the single facer or the double backer in response to excursions of the dancer from a reference position to allow the single face material to spend a uniform time between the single face and double back processes. Also, a steering assembly is positioned on the bridge to align the web from the single facer with the machine center line of the double backer.

Abstract: A registration target for printing on a web or sheet includes a pair of juxtaposed orthogonal arms, at least one of which extends lengthwise along the web. One or more tabs projects perpendicularly from each arm but only at one edge thereof. The widths of the arms and tabs substantially correspond to the stroke width of the lines and characters being printed on the web and the length of each tab is a multiple of that stroke width. By observing the orientations of the tabs and the amounts by which they project beyond one another of the targets printed by a series of print cylinders in a press, one can immediately discern the directions and amounts in terms of stroke width of any registration errors.