Added value of a task model and role of metacognition in learning

A printed web marker is used in combination with a multiroll printing press. A web marker is positioned downstream of the last of the rolls for marking defective portions of the printed web. A central controller operates the marker and the controller has off, delay and on control modes. The marker does not operate when in the off mode and marking commences upon expiration of a predetermined period when the controller is shifted from the off to the delay mode and continues thereafter and for a predetermined period after the controller is shifted from the delay to the off mode. Marking commences instantaneously upon the controller being shifted from the off to the on mode. Switches and operators cause the controller to be shifted between the modes so that only defective portions of the web are marked.