The Science of Doctor Blades

Anilox scoring

Cause: Scoring not only mars a print job, but also permanently damages the surface of the anilox roll. The problem usually occurs as a result of excessive pressure on the doctor blade, causing the blade to trap insoluble particles and damage the anilox. Over time, explained Bobby Furr, technical product manager for HarperScientific.com®, a division of Harper Corp. of America (Charlotte, N.C.), "Material from the doctor blade goes back through the ink train, lodges up behind the doctor blade, and starts grinding on the anilox roll." The anilox cell walls are ripped apart by the trapped material—such as wear debris from the blade or ceramic pieces from the damaged anilox—and a groove is formed in the roll. "Most of the time it goes undetected until the line starts to appear in the printed substrate, and then it is too late," Furr said.