DEFINITE FORM PAPER FEEDER

摘要

An overhead unit used with a printer having a platen for feeding continuous, fan-folded, edge perforated forms. Tractors engage the feed perforations on the forms. The unit automatically bursts the side perforations by the use of flexural members which extract energy from the forms feed and oscillate to burst the side perforations. Bursting of the cross perforations is carried out by a pivotally mounted, lever actuated bar which engages the platen and forms a toggle therewith to engage the successive forms against the platen just below the cross perforations; the toggle being arranged to tighten and increase the clamping force, as the form is pulled away from the platen when bursting the cross perforations. A roller assembly including rollers engaging the outside of the loop on the infeed or upstream side of the platen removes any platen wave due to differential displacement of the forms as they travel with linear motion through the tractors and with rotational motion around the platen. These rollers also steer the form to counteract lateral meandering thereof on the platen. Other rollers on the infeed side of the tractors wrap the forms to at least a 90 DEG arc to eliminate positive tents at the cross perforations. Backlash is removed by a diagonally split collet and tapered sleeve which controls the clearance between the tractor drive shaft and the sprockets of the tractors. Additional rollers on the drive shaft and the support shaft for the tractors, which can be used together with fingers extending from the support shaft, stiffen the forms between the tractors.