Method of controlled laser imaging of zirconia alloy ceramic

Abstract

Reusable lithographic printing members are prepared from a zirconia ceramic that is an alloy of ZrO.sub.2 and a second oxide chosen from MgO, CaO, Y.sub.2 O.sub.3, Sc.sub.2 O.sub.3, a rare earth oxide or a combination of any of these. In use, a printing surface of the zirconia alloy ceramic is imagewise exposed to electromagnetic radiation such as from a laser under controlled conditions to provide localized 'melting' of the zirconia in the exposed areas. Those areas are transformed from a hydrophilic to an oleophilic state or from an oleophilic to a hydrophilic state, thereby creating a lithographic printing surface which is hydrophilic in non-image areas and is oleophilic and thus capable of accepting printing ink in image areas. Such inked areas can then be used to transfer an image to a suitable substrate in lithographic printing. The printing members are directly laser-imageable as well as image erasable, and can include printing plates, printing cylinders, printing tapes and printing sleeves.