Abstract Successive areas of recording medium, having a precursor (methylene blue) reduceable with a low level of energy, are exposed to monochromatic (red) laser output for forming a record. The precursor is carried in a thin thermoplastic film from a substrate, has a color complementary to the color of the laser output, and is opaque to the wave length of energy to be used for sensing the record. A latent reducing agent included in the recording medium is carried in a thin thermoplastic film supported from the substrate. It releases a reducing agent which react with the precursor upon exposure of the medium to the laser output to reduce the precursor to a state (leuco form) which is permeable (transparent) to the wave length of the record sensing energy. Spontaneous reduction of the precursor is prevented, according to a modified embodiment of the disclosure, by an inert barrier comprised of a thermoplastic film sandwiched in the recording medium between the films containing the precursor and the reducing agent.
A device according to claim 1 wherein the solvent of the binder of the precurSor layer is water.
Claim 2
Dependent Claim
25 words
A device according to claim 1 wherein the solvents of said precursor and second layers are water and the solvent of said barrier is organic.
Claim 3
Dependent Claim
39 words
A device according to claim 3 wherein the binder material of said precursor and second layers is at least one substance selected from the class comprised of gelatin, locust bean gum, starch, polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl acetate.
Claim 4
Dependent Claim
29 words
A device according to claim 4 wherein the binder material of said barrier is at least one substance selected from the class comprising polyvinyl chloride, polyvinyl acrylic, and polystyrene.