Process for graining and anodizing a metal plate

• Main Authors: ROZELL; WILLIAM J, GRACIA; ROBERT F, FROMSON; HOWARD A
• Format: Patent
• Language: English
• Published: 29.07.1997
• Edition: 6
• Subjects: GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; LINING MACHINES; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING,INKING, DAMPING, OR THE LIKE; PERFORMING OPERATIONS; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM; PRINTING; PRINTING PLATES OR FOILS; STAMPS; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ARTCOLLECTIONS [XRACs] AND DIGESTS; TRANSPORTING; TYPEWRITERS

Smooth planar metal surfaces, usually an aluminum web, intended for a lithographic printing plate, are roughened by brush graining with fine abrasive particles which are hard and dense and have a radial or disk-like configuration such that the abrasive particles are forged into the surface of the metal forming cavities in which the abrasive particles remain embedded. The embedded abrasive particles are dislodged and removed from the cavities by subjecting the web to an anodic treatment employing electrolyte materials and concentrations, temperatures and voltage which will dislodge and remove the particles while retaining the surface texture or morphology of the as-roughened surface. The web is then subjected to a second anodic treatment under conditions which favor oxide formation in order to provide a final anodized product.