Electrosensitive recording materials with heterogeneous surface topology

Claim 1

In electrosensitive recording materials of the type including (a) a substrate web, (b) an intermediate colored layer on a surface of the substrate web, and (c) a vacuum-deposited metal layer over the intermediate layer, which recording materials develop an image when portions of the metal layer are vaporized when subjected to electric current from a printhead in contact therewith to thereby expose portions of the colored intermediate layer, the improvement wherein: (1) the substrate is a web of paper of plastic film with a first surface having a smoothness of 20 or less Sheffield units and an ink absorption characteristic providing a brightness loss of 10 to 40 units; (2) the intermediate layer is on the first surface of the substrate web and includes (a) a thermally stable organic film-forming binder, (b) small-sized solid parrticulates having a particle size range of 0.1 to 2.0 microns average diameter, and (c) large-sized solid particulates having a particle size range of 2 to 39 microns with a median particle size of 3 to 12 microns, the binder forming a film adhering the small-sized and large-sized particulates to the first surface of the substrate, the particulates being partially embedded in the film with the large-sized particulates having portions protruding from the film and extending beyond portions of the small-sized particulates protruding from the film, the intermediate layer thereby having a heterogeneous surface topology formed by the small-sized particulates dispersed within agglomerates of the large-sized particulates; and (3) the vacuum-deposited metal layer is a thin even layer of metal extending over and conforming to the heterogeneous surface topology of the intermediate layer.