Thermal imaging medium

Claim 1

A thermal imaging laminar medium, actuatable in response to intense image-forming radiation for production of an image, said laminar medium comprising, in order: a first sheet, said sheet being transparent to said image-forming radiation and having at least a surface zone or layer of polymeric material heat-activatable upon subjection of said thermal imaging medium to brief and intense radiation; a thermoplastic intermediate layer having cohesivity in excess of its adhesivity for said surface zone or layer of heat-activatable polymeric material; an image-forming layer on said thermoplastic intermediate layer, said image-forming layer comprising an image-forming colorant material in a binder therefor, said image-forming layer having adhesivity for said thermoplastic intermediate layer in excess of the adhesivity of said thermoplastic intermediate layer for said surface zone or layer of heat-activatable polymeric material; and a second sheet covering said image-forming layer and laminated directly or indirectly to said image-forming layer; said thermal imaging medium being capable of absorbing radiation at or near the interface of said surface zone or layer of heat-activatable polymeric material and said thermoplastic intermediate layer, at the wavelength of the exposing source, and being capable of converting absorbed energy into thermal energy of sufficient intensity to heat activate said surface zone or layer rapidly; said heat-activated surface zone or layer, upon rapid cooling, attaching said thermoplastic intermediate layer firmly to said first sheet; said thermal imaging medium being adapted to image formation by imagewise exposure of portions of said thermal imaging medium to radiation of sufficient intensity to attach exposed portions of said thermoplastic intermediate layer and said image-forming layer firmly to said first sheet and by removal to said second sheet upon separation of said first and second sheets after said imagewise exposure, of unexposed portions of said image-forming layer and said thermoplastic intermediate layer, thereby to provide first and second images, respectively, on said first and second sheets; said thermoplastic intermediate layer providing surface protection for said second image on said second sheet.