Patent ID: 6354213
Filing Date: 2002-03-12
Classification: B41F,B41P

Abstract:
A method of cleaning a metering roll of a printing press, said metering having a metal core with a ceramic coating, said ceramic coating having a plurality of cells each having a bottom, each having a widest span, and each containing a polymeric contaminant, said method comprising the steps of:pulsating a laser beam on and off to individually fire at each of said plurality of cells; focusing said laser beam at a first region of said ceramic coating with said first region containing a first cell of said plurality of cells, said first region being at least twice as wide as said widest span of said first cell, said laser beam being focused toward a focal point defined as that point in space where said laser beam converges to a minimum width if it were unobstructed, said focal point being below said bottom of said first cell when focusing said laser beam at said first region; raising the temperature of said first region to 400Â° F. to 1,000Â° F. which is above a polymeric disassociation temperature of said polymeric contaminant but below a ceramic disassociation temperature of said ceramic coating, thereby destroying said polymeric contaminant within said first region while leaving said ceramic coating substantially intact; blowing a gas at said first region to expel said polymeric contaminant from said first cell, said gas being at a temperature below said polymeric disassociation temperature to cool said first region; changing a longitudinal position of said metering roll relative to said laser beam and changing a circumferential position of said metering roll relative to said laser beam at a substantially constant rate of revolutions per unit of time, thereby allowing said first region to cool further to a level below said polymeric disassociation temperature; focusing said laser beam at a second region of said ceramic coating, said second region being spaced apart from said first region, said second region containing a second cell of said plurality of cells, said second region being at least twice as wide as said widest span of said second cell, said focal point being below said bottom of said second cell when focusing said laser beam at said first region; raising the temperature of said second region to 400Â° F. to 1,000Â° F. which is above said polymeric disassociation temperature but below said ceramic disassociation temperature, thereby destroying said polymeric contaminant within said second region while leaving said ceramic coating substantially intact; and blowing said gas at said second region to expel said polymeric contaminant from said second cell and to cool said second region.