# US 7,407,538 B2 · IR transparent inkjet ink set > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,407,538 B2 - Document ID: US7407538B2 - Status: Granted - Kind: B2 - Application number: 11/208,900 - Filed: 2005-08-22 - Published: 2006-03-09 - Granted: 2008-08-05 - Earliest claimed: 2004-09-08 - Assignees: E.I. du Pont de Nemours and Company - Inventors: Christian Jackson - Web page: https://patentgrep.com/patent/US7407538B2 ## CPC - C09D 11/40: Ink-sets specially adapted for multi-colour inkjet printing - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) ## Abstract The present invention pertains to an ink set comprising at least four different colored visible inks, for example BGMY, wherein none of the visible inks absorb significantly in the near infrared region (IR transparent). ## Claims ### Claim 1 An inkjet ink set comprising at least four visible inks, wherein the at least four visible inks comprise a first ink blue in color, a second ink green in color, a third ink magenta in color and a fourth ink yellow in color, wherein each of the first, second, third and fourth inks individually comprises a vehicle and a soluble colorant, and wherein the visible inks of the ink set are substantially transparent in the near-infrared region, wherein the inks of the ink set contain substantially no individual colorant that in and of itself is cyan in color. ### Claim 2 (depends on 1) The ink set of claim 1, wherein the ink set contains substantially no ink that is cyan in color. ### Claim 3 (depends on 1) The ink set of claim 1, wherein the blue ink has a hue angle of between 250 and 320; the green ink has a hue angle of between 120 and 180; the magenta ink has a hue angle of between 320 and 10; and the yellow ink has a hue angle of between 70 and 120. ### Claim 4 (depends on 1) The ink set of claim 1, wherein the colorants in the visible inks have an absorbance ratio in the 850-900 nm region of about 1% or less; and/or an absorbance ratio in the 800-900 nm region of about 2% or less; and/or an absorbance ratio in the 750-900 nm region of about 7.5% or less. ### Claim 5 (depends on 1) The ink set of claim 1, further comprising a fifth ink black in color comprising a vehicle and a black colorant. ### Claim 6 (depends on 1) The ink set of claim 1, wherein the vehicle of each ink in the ink set is, individually, an aqueous vehicle. ### Claim 7 (depends on 1) The ink set of claim 1, wherein the colorant in the first ink is selected from the group consisting of Reactive Blue 49, Reactive Blue 19, Reactive Blue 72, Reactive Blue 21, Acid Blue 83, Acid Blue 260 and combinations thereof; and/or the colorant in the second ink is selected from the group consisting of Reactive Green 12, a Reactive Blue 72/Reactive Yellow 85 mixture, and combinations thereof; and/or the colorant in the third ink is selected from Acid Red 52, Reactive Red 180, Acid Red 37, Reactive Red 23 and combinations thereof; and/or the colorant in the fourth ink is selected from the group consisting of Direct Yellow 86, Direct Yellow 132, Acid Yellow 23 and combinations thereof. ### Claim 8 (depends on 1) The ink set of claim 1, further comprising an invisible ink comprising a vehicle and an infrared marker. ### Claim 9 A method for ink jet printing onto a substrate, comprising the steps of: (a) providing an ink jet printer that is responsive to digital data signals; (b) loading the printer with a substrate to be printed; (c) loading the printer with an inkjet ink set; and (d) printing onto the substrate using the inkjet ink set in response to the digital data signals, wherein the inkjet ink set comprises at least four visible inks, wherein the at least four visible inks comprise a first ink blue in color, a second ink green in color, a third ink magenta in color and a fourth ink yellow in color, wherein each of the first, second, third and fourth inks individually comprises a vehicle and a soluble colorant, and wherein the visible inks of the ink set are substantially transparent in the near-infrared region, and wherein the inks of the ink set contain substantially no individual colorant that in and of itself is cyan in color. ### Claim 10 (depends on 9) The method of claim 9, wherein the substrate to be printed contains invisible markings that absorb or fluoresce in the near-infrared region, and which invisible markings remain detectable when overprinted with the visible inks of the ink set. ### Claim 11 (depends on 9) The method of claim 9, wherein the blue ink has a hue angle of between 250 and 320; the green ink has a hue angle of between 120 and 180; the magenta ink has a hue angle of between 320 and 10; and the yellow ink has a hue angle of between 70 and 120. ### Claim 12 (depends on 9) The method of claim 9, wherein the colorants in the visible inks have an absorbance ratio in the 850-900 nm region of about 1% or less; and/or an absorbance ratio in the 800-900 nm region of about 2% or less; and/or an absorbance ratio in the 750-900 nm region of about 7.5% or less. ### Claim 13 (depends on 9) The method of claim 9, wherein the ink set further comprises a fifth ink black in color comprising a vehicle and a black colorant. ### Claim 14 (depends on 9) The method of claim 9, wherein the colorant in the first ink is selected from the group consisting of Reactive Blue 49, Reactive Blue 19, Reactive Blue 72, Reactive Blue 21, Acid Blue 83, Acid Blue 260 and combinations thereof; and/or the colorant in the second ink is selected from the group consisting of Reactive Green 12, a Reactive Blue 72/Reactive Yellow 85 mixture, and combinations thereof; and/or the colorant in the third ink is selected from Acid Red 52, Reactive Red 180, Acid Red 37, Reactive Red 23 and combinations thereof; and/or the colorant in the fourth ink is selected from the group consisting of Direct Yellow 86, Direct Yellow 132, Acid Yellow 23 and combinations thereof. ### Claim 15 (depends on 9) The method of claim 9, wherein the ink set further comprises an invisible ink comprising a vehicle and an infrared marker.