Direct Thermal Recording Media Based on Selective Change of State

A recording medium, comprising:

• a substrate;
• a light-scattering layer carried by the substrate, the light-scattering layer being substantially devoid of leuco dyes and acidic developers;
• and
• a colorant carried by the substrate and disposed between the substrate and the light-scattering layer;
• wherein the recording medium is configured for use with a thermal printer, and wherein a print quality of the recording medium when used with a thermal printer energy setting of 11.7 mJ/mm2 at a print speed of 6 inches per second (ips) is characterized by an ANSI value of at least 1.5.

A recording medium, comprising:

• a flexible substrate;
• a light-scattering layer carried by the substrate and including first solid scattering particles having a first melting point and second solid scattering particles having a second melting point, the light-scattering layer being porous and substantially devoid of leuco dyes and acidic developers;
• and
• a thermal insulating layer and a colorant disposed between the substrate and the light-scattering layer;
• wherein the second melting point is at least 80° C. and the first melting point is at least 50° C. greater than the second melting point;
• and
• wherein the recording medium is configured for use with a thermal printer to provide thermally-induced images resulting from selective melting of the second solid scattering particles to fill spaces between the first solid scattering particles, and wherein a print quality of the recording medium when used with a thermal printer energy setting of 11.7 mJ/mm2 at a print speed of 6 inches per second (ips) is characterized by an ANSI value of at least 1.5.

A recording medium, comprising:

• a flexible substrate;
• a first light-scattering layer carried by the substrate and including first solid scattering particles having a first melting point, the first light-scattering layer being porous;
• a second light-scattering layer including second solid scattering particles having a second melting point, the second light-scattering layer being disposed proximate the first light-scattering layer;
• and
• a thermal insulating layer and a colorant disposed between the first light-scattering layer and the substrate;
• wherein the second melting point is at least 80° C. and the first melting point is at least 50° C. greater than the second melting point;
• wherein the first and second light-scattering layers are substantially devoid of leuco dyes and acidic developers;
• and
• wherein the recording medium is configured for use with a thermal printer to provide thermally-induced images resulting from selective melting of the second solid scattering particles to fill spaces between the first solid scattering particles, and wherein a print quality of the recording medium when used with a thermal printer energy setting of 11.7 mJ/mm2 at a print speed of 6 inches per second (ips) is characterized by an ANSI value of at least 1.5.

A method of making a recording medium, comprising:

• providing a substrate and a colorant;
• forming a first light-scattering layer atop the substrate and the colorant, the first light-scattering layer being porous and comprising first solid scattering particles having a first melting point;
• and
• as part of the forming the first light-scattering layer, or in a separate step of forming a second light-scattering layer, providing a plurality of second solid scattering particles proximate the first light-scattering layer, the second solid scattering particles having a second melting point;
• wherein the second melting point is sufficiently lower than the first melting point such that the recording medium is adapted for dynamic thermal printing wherein the second solid scattering particles, but not the first solid scattering particles, melt at selected print locations, and the second solid scattering particles, when melted, fill spaces between the first solid scattering particles.