Method of controlled laser imaging of zirconia alloy ceramic lithographic member to provide localized melting in exposed areas

A method of lithographic printing comprising the steps of:

• A) providing a lithographic printing member having a printing surface composed of a zirconia ceramic that is an alloy of ZrO.sub.2 and a secondary oxide selected from the group consisting of MgO, CaO, Y.sub.2 O.sub.3, Sc.sub.2 O.sub.3, a rare earth oxide, and combinations thereof, said zirconia alloy ceramic having a density of from about 5.6 to about 6.2 g/cm.sup.3, and
• B) providing an image on said printing surface by imagewise exposing said printing surface to electromagnetic radiation provided by a laser under the following conditions:
• an average power level of from about 0.1 to about 50 watts,
• a peak power of from about 6,000 to about 100,000 watts,
• a pulse rate up to 50 kHz, and
• an average pulse width of from about 50 to about 500 .mu.sec,
• so as to melt the zirconia in the exposed areas of said printing surface, and to transform said printing surface from a hydrophilic to an oleophilic state or from an oleophilic to a hydrophilic state in said exposed areas of said printing surface, thereby creating a lithographic printing surface having both image areas and non-image areas,
• C) contacting said lithographic printing surface with an aqueous fountain solution and a lithographic printing ink, thereby forming an inked lithographic printing surface, and
• D) contacting said inked lithographic printing surface with a substrate to thereby transfer said printing ink to said substrate, forming an image thereon.