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Abstract

The performance-limiting effects of thermal breakdown on ablation-type lithographic printing plates are overcome by rendering the ink-accepting surface largely impervious to the effects of debris originating with the surface layer of the printing member, or by discouraging the formation of harmful debris altogether. In one approach, the ink-accepting surface is a highly crosslinked polymer. The resulting cured matrix exhibits a sufficient degree of three-dimensional bonding to resist melting, softening, or chemical degradation as a result of the imaging process. Alternatively, an intervening layer, disposed between the imaging layer and the surface layer, prevents the surface layer from undergoing significant thermal degradation in response to imaging radiation or ablation of the underlying imaging layer, and is also formulated to produce little debris or debris having an affinity for ink and/or fountain solution similar to the affinity of the substrate--e.g., which does not reduce the oleophilicity of the underlying ink-accepting surface. Following imaging, the remnants of the insulating layer are removed along with the surface layer where the plate received imaging radiation.

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First Claim