Patent ID: 6792854
Filing Date: 2004-09-21
Classification: B41F

Abstract:
A system for metering viscous liquid coatings onto a circumferential surface of a rotating roller having a velocity essentially equal to a surface velocity of the item being printed, comprised of:a bag-shaped liquid coating reservoir comprising elastomeric-film walls, a bottom wall of said liquid coating reservoir having attached thereto a plurality of elastormeric tubing sections each of which penetrate the bottom wall of said liquid coating reservoir, where the exterior surface of the first ends of said elastomeric tubing sections are sealed liquid tight to said bottom wall, said elastomeric tubing sections extending through, and providing the elastormeric tubular element of a plurality of peristaltic liquid coating metering pumps, each controlling a flow rate and a thickness of one of a series of contiguous bands of liquid coating across the circumferential surface of said rotating roller and wherein said peristaltic liquid coating metering pumps are comprised of a plurality of rollers sequentially and progressively pressing and rolling against said elastomeric tubing sections, thereby temporarily collapsing a length of the tubing walls, the progressing collapsed length causing liquid contained in the tubes to travel away from said liquid coating reservoir as the rollers progress along said tubes, said rollers being caused to progress along said tubes by an oscillating lever connected by a unidirectional coupling means to a frame supporting said plurality of rollers, said flow rate from said peristaltic liquid coating metering pumps being varied by a signal from a computer control means which limits the rotary motion of said oscillating fevers, and wherein the second ends of said elastomeric tubing sections are formed into a flared and flattened closed shaped orifice not permanently sealed together, to prevent retrograde motion of the liquid coating contained therein, and to provide a closure when not dispensing to prevent dripping of said liquid coating, and to prevent entrance of air and contaminants into said orifice, and to provide variable apertures on the second end proportional to a pressure of said liquid coatings flowing through said elastomeric tubes, wherein said pressure bends apart the flared and flattened end surfaces of said second ends a vertical distance proportional to said pressure, thereby dispensing a flat ribbon of said liquid onto said rotating roller in a sequence of contiguous bands of coating regardless of the flow rate, and wherein one of the flattened surfaces of said second end is urged into contact with said rotating roller.