# US 6,294,308 B1 · Thermal imaging process and products using image rigidification > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,294,308 B1 - Document ID: US6294308B1 - Status: Granted - Kind: B1 - Application number: 09/419,680 - Filed: 1999-10-15 - Granted: 2001-09-25 - Earliest claimed: 1999-10-15 - Assignees: E. I. Du Pont de Nemours and Company - Inventors: Jonathan V. Caspar; Harvey Walter Taylor, Jr.; Gregory C. Weed; Rolf S. Gabrielsen - Web page: https://patentgrep.com/patent/US6294308B1 ## CPC - B41M 5/392: Additives, other than colour forming substances, dyes or pigments, e.g. sensitisers, transfer promoting agents - B41M 5/38214: {Structural details, e.g. multilayer systems (composition of individual layers B41M5/42)} - B41M 5/42: Intermediate, {backcoat}, or covering layers {(B41M5/405 takes precedence; multilayer thermal transfer systems in general B41M5/38214)} - B41M 5/5227: {characterised by organic non-macromolecular additives, e.g. UV-absorbers, plasticisers, surfactants} - B41M 7/0027: {using protective coatings or layers by lamination or by fusion of the coatings or layers} - G03F 3/108: {using a non-impact printing method, e.g. ink jet, using duplicating or marking methods covered by B41M5/00, e.g. by ablation or by thermographic means} - B41M 5/426: {characterised by inorganic compounds, e.g. metals, metal salts, metal complexes} - B41M 5/52: Macromolecular coatings - B41M 2205/02: Dye diffusion thermal transfer printing (D2T2) - B41M 2205/38: Intermediate layers; Layers between substrate and imaging layer - Y10S 430/145: Infrared - B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P) - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract Improved processes and products for laser thermal imaging are described. These improved processes and products utilize an image rigidification element and significantly reduce halftone dot movement, swath boundary cracking and banding. ## Claims ### Claim 1 A method for making a color image comprising: (1) imagewise exposing to laser radiation a laserable assemblage comprising: (A) a thermally imageable element comprising a thermally imageable layer which comprises a colorant and a polymeric binder, the colorant consisting of a pigment; and (B) a receiver element in contact with the thermally imageable layer of the thermally imageable element; the receiver element comprising: (a) an image receiving layer; and (b) a receiver support; whereby the exposed areas of the thermally imageable layer are transferred to the receiver element to form a colored image on the image receiving layer; (2) separating the thermally imageable element (A) from the receiver element (B), thereby revealing the colored image on the image receiving layer of the receiver element; (3) contacting the colored image on the image receiving layer of the receiver element with an image rigidification element comprising: (c) a support having a release surface, and (d) a thermoplastic polymer layer, the colored image being adjacent to the thermoplastic polymer layer during said contacting whereby the colored image is encased between the thermoplastic polymer layer and the image receiving layer of the receiver element; (4) removing the support having a release surface thereby revealing the thermoplastic polymer layer; and (5) contacting the revealed thermoplastic polymer layer from step (4) with a permanent substrate. ### Claim 2 (depends on 1) The method of claim 1 wherein the receiver support is transparent. ### Claim 3 (depends on 1) The method of claim 1 further comprising: (1) removing the receiver support. ### Claim 4 (depends on 1) The method of claim 1 wherein the permanent substrate is paper. ### Claim 5 (depends on 1) The method of claim 1 wherein the permanent substrate is a polyester film. ### Claim 6 (depends on 1) The method of claim 1 wherein the exposure step is effected at a laser fluence of at most 600 mJ/cm2. ### Claim 7 (depends on 1) The method of claim 1 wherein the thermally imageable element is prepared by coating the thermally imageable layer on a base element. ### Claim 8 (depends on 7) The method of claim 7 wherein the thermally imageable layer is applied as an aqueous coating. ### Claim 9 (depends on 7) The method of claim 7 wherein the base element comprises: (a) an ejection or subbing layer; and (b) a heating layer. ### Claim 10 (depends on 9) The method of claim 9 wherein (a) is an ejection layer. ### Claim 11 (depends on 9) The method of claim 9 wherein (a) is an subbing layer. ### Claim 12 (depends on 7) The method of claim 7 wherein the base element comprises: (a) a heating layer, and (b) a base element support. ### Claim 13 (depends on 1) The method of claim 1 wherein the polymeric binder is a low decomposition temperature polymer having a decomposition temperature greater than about 350° C. ### Claim 14 (depends on 1, 3) The method of claim 1 or 3 wherein the thermally imageable element or the image receiving layer of the receiver element comprises a thermal amplification additive. ### Claim 15 (depends on 14) The method of claim 14 wherein the thermal amplification additive is selected from the group consisting essentially of diazo alkyls, diazonium salts, azido (-N3) compounds; ammonium salts; oxides which decompose to form oxygen; carbonates; peroxides and mixtures thereof. ### Claim 16 (depends on 14) The method of claim 14 wherein the thermal amplification additive is 4-diazo-N,N′ diethyl-aniline fluoroborate. ### Claim 17 (depends on 14) The method of claim 14 wherein the thermal amplification additive is a near infrared absorbing (NIR) dye. ### Claim 18 (depends on 17) The method of claim 17 wherein the NIR dye is selected from the group consisting of poly(substituted) phthalocyanine compounds, metal-containing phthalocyanine compounds; cyanine dyes; squarylium dyes; chalcogenopyryioacrylidene dyes; croconium dyes; metal thiolate dyes; bis(chalcogenopyrylo) polymethine dyes; oxyindolizine dyes; bis(aminoaryl) polymethine dyes; merocyanine dyes; quinoid dyes and mixtures thereof. ### Claim 19 (depends on 1, 3) The method of claim 1 or 3 wherein the image receiving layer of the receiver element comprises a crystalline polymer. ### Claim 20 (depends on 19) The method of claim 19 wherein the image receiving layer has a melting point of 50 to 64° C. ### Claim 21 (depends on 20) The method of claim 20 wherein the image receiving layer has a melting point of 56 to 64° C. ### Claim 22 (depends on 21) The method of claim 21 wherein the image receiving layer has a melting point of 58 to 62° C. ### Claim 23 (depends on 19) The method of claim 19 wherein the crystalline polymer is polycaprolactone. ### Claim 24 (depends on 1, 3) The method of claim 1 or 3 wherein the image rigidification element support having a release surface comprises a support and a release layer. ### Claim 25 (depends on 24) The method of claim 24 wherein the release layer is selected from the group consisting of silicones; melamine acrylic resins; vinyl chloride polymers; vinyl chloride copolymers; vinyl acetate polymers; vinyl acetate copolymers; plasticized polyvinyl alcohols; ethylene; propylene polymers and propylene copolymers. ### Claim 26 (depends on 1, 3) The method of claim 1 or 3 wherein the thermoplastic polymer is selected from the group consisting essentially of polyester, methacrylate, acrylate, polyvinylacetate, polyvinylbutyral, polyvinylformal, styrene-isoprene-styrene and styrene-ethylene-butylene-styrene polymers. ### Claim 27 (depends on 1, 3) The method of claim 1 or 3 wherein the thermoplastic polymer is amorphous. ### Claim 28 (depends on 27) The method of claim 27 wherein the thermoplastic polymer has a Tg in the range of 30 to 150° C. ### Claim 29 (depends on 28) The method of claim 28 wherein the thermoplastic polymer has a Tg in the range of 40 to 70° C. ### Claim 30 (depends on 29) The method of claim 29 wherein the thermoplastic polymer has a Tg in the range of 40 to 55° C. ### Claim 31 (depends on 27) The method of claim 27 wherein the thermoplastic polymer is compatible with the image receiving layer. ### Claim 32 (depends on 27) The method of claim 27 wherein the thermoplastic polymer is polyester. ### Claim 33 (depends on 1, 3) The method of claim 1 or 3 further comprising before step (3): (2a) repeating steps (1) to (2) at least once using a different thermally imageable element to from a colored image comprising at least two colors on the same image receiving layer. ### Claim 34 (depends on 33) The method of claim 33 wherein steps (1) and (2) are repeated at least twice to form a colored image comprising at least four colors. ### Claim 35 (depends on 1, 3) The method of claim 1 or 3 wherein contact of the colored image on the image receiving layer of the receiver element with the image rigidification element is accomplished by lamination. ### Claim 36 (depends on 35) The method of claim 35 wherein lamination takes place at speeds of at least 600 mm/min. ### Claim 37 (depends on 35) The method of claim 35 wherein lamination takes place at speeds of at least 800 mm/min. ### Claim 38 (depends on 1, 3) The method of claim 1 or 3 wherein contact of the revealed thermoplastic polymer layer to the permanent substrate is accomplished by lamination. ### Claim 39 (depends on 38) The method of claim 38 wherein lamination takes place at speeds of at least 600 mm/min. ### Claim 40 A method for making a color image comprising: (1) imagewise exposing to laser radiation a laserable assemblage comprising: (A) a thermally imageable element comprising a thermally imageable layer; and (B) a receiver element in contact with the thermally imageable layer of the thermally imageable element; the receiver element comprising: (a) an image receiving layer; (b) a receiver support; and (C) the thermally imageable element comprising a near infrared absorbing dye or the image receiving layer comprising a near infrared absorbing dye; whereby the exposed areas of the thermally imageable layer are transferred to the receiver element to form a colored image on the image receiving layer; (2) separating the thermally imageable element (A) from the receiver element (B), thereby revealing the colored image on the image receiving layer of the receiver element; (3) contacting the colored image on the image receiving layer of the receiver element with an image rigidification element comprising: (c) a support having a release surface, and (d) a thermoplastic polymer layer comprising an NIR dye bleaching agent, the colored image being adjacent to the thermoplastic polymer layer during said contacting whereby the colored image is encased between the thermoplastic polymer layer and the image receiving layer of the receiver element; (4) removing the support having a release surface thereby revealing the thermoplastic polymer layer; and (5) contacting the revealed thermoplastic polymer layer from step (4) with a permanent substrate. ### Claim 41 (depends on 40) The method of claim 40 wherein the NIR dye bleaching agent is selected from the group consisting of amines, azo compounds, carbonyl compounds and, organometallic compounds, carbanions, peroxides, diacylperoxides, peroxy acids, hydroperoxides, persulfates, and halogen compounds.