Thermal transfer ribbon

• US 7,829,162 B2
• Filed: 08/28/2007
• Issued: 11/09/2010
• Est. Priority Date: 08/29/2006
• Status: Expired due to Fees

• Current Assignee: International Imaging Materials Inc. (IIMAK Holding Corp.)
• Original Assignee: International Imaging Materials Inc. (IIMAK Holding Corp.)
• Inventors: Przybylo, John, Eskra, Jennifer, Marginean, Barry L., Geddes, Pamela A., Jalbert, Claire A., Harrison, Daniel J.
• Primary Examiner(s): Shewareged; Betelhem
• Application Number:
  US11/895,841
• Publication Number:
  US 20080090726A1
• Time in Patent Office: 1,169 Days
• Field of Search: 428/32.63, 428/32.64, 428/32.69, 428/32.8, 428/32.87, 428/200, 428/207, 428/210, 428/212, 428/325, 400/241, 400/241.1, 400/241.4
• US Class Current: 428/32.69
• CPC Class Codes: B41M 2205/06 relating to melt (thermal) mass transfer
• CPC Class Codes: B41M 5/385 characterised by the transferable dyes or pigments infrared absorbing dyes B41M5/465
• CPC Class Codes: B41M 5/41 Base layers supports or substrates
• CPC Class Codes: Y10T 428/24843 with heat sealable or heat releasable adhesive layer
• CPC Class Codes: Y10T 428/24901 including coloring matter
• CPC Class Codes: Y10T 428/24926 including ceramic, glass, porcelain or quartz layer
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/252 Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]

Abstract

A thermal transfer printing medium that contains a thermal transfer layer which contains a first taggant and colorant, wherein: the first taggant comprises a fluorescent compound with an excitation wavelength selected from the group consisting of wavelengths of less than 400 nanometers, wavelengths of greater than 700 nanometers. When the thermal transfer layer is printed onto a white polyester substrate with a gloss of at least about 84, a surface smoothness Rz value of 1.2, and a reflective color represented by a chromaticity (a) of 1.91 and (b) of −6.79 and a lightness (L) of 95.63, when expressed by the CIE Lab color coordinate system, and when such printing utilizes a printing speed of 2.5 centimeters per second and a printing energy of 3.2 joules per square centimeter, a printed substrate with certain properties is produced. The printed substrate has a reflective color represented by a chromaticity (a) of from −15 to 15 and (b) from −18 to 18, and the printed substrate has a lightness (L) of less than about 35, when expressed by the CIE Lab color coordinate system. When the printed substrate is illuminated with light source that excites the first taggant with an excitation wavelength selected from the group consisting of wavelengths of less than 400 nanometers, wavelengths greater than 700 nanometers, the printed substrate produces a light fluorescence with a wavelength of from about 300 to about 700 nanometers.

Claims

1. A thermal transfer printing medium comprised of a thermal transfer layer, wherein:

(a) said thermal transfer layer is comprised of a first colorant and a first taggant, wherein said first taggant comprises a fluorescent compound with a first excitation wavelength, and wherein said first excitation wavelength is selected from the group consisting of wavelengths of less than 400 nanometers, wavelengths of greater than 700 nanometers, and mixtures thereof;

(b) said thermal transfer layer has a light transmittance of at least about 10 percent when illuminated by light having said first excitation wavelength of said first taggant;

(c) when said thermal transfer layer is printed onto a white polyester substrate with a gloss of at least about 84, a surface smoothness Rz value of 1.2, and a reflective color represented by a chromaticity (a) of 1.91 and (b) of −

6.79 and a lightness (L) of 95.63, when expressed by the CIE Lab color coordinate system, and when such printing utilizes a printing speed of 2.5 centimeters per second and a printing energy of 3.2 joules per square centimeter, a printed substrate is produced wherein;

1. said printed substrate has a reflective color represented by a chromaticity (a) of from −

15 to 15 and (b) from −

18 to 18, and said printed substrate has a lightness (L) of less than about 35, when expressed by the CIE Lab color coordinate system; and

2. when said printed substrate is illuminated with light source that excites said first taggant with said first excitation wavelength, said printed substrate produces a light fluorescence with a wavelength in the range of from about 300 to about 700 nanometers.

2. The thermal transfer medium as recited in claim 1, wherein said first taggant is an oxysulfide phosphor.

3. The thermal transfer medium as recited in claim 1, wherein said thermal transfer layer is comprised of said first colorant and a second colorant.

4. The thermal transfer medium as recited in claim 3, wherein said thermal transfer layer has a thickness of less than about 15 microns.

5. The thermal transfer medium as recited in claim 3, wherein said thermal transfer layer has a thickness of less than about 10 microns.

6. The thermal transfer medium as recited in claim 3, wherein said thermal transfer layer has a thickness of less than about 5 microns.

7. The thermal transfer medium as recited in claim 5, wherein the absorbance of light at said first excitation wavelength by each of said first colorant and said second colorant in said thermal transfer layer is low enough such that said thermal transfer layer has a light transmittance of at least about 20 percent.

8. The thermal transfer medium as recited in claim 5, wherein the absorbance of light at said first excitation wavelength by each of said first colorant and said second colorant in said thermal transfer layer is low enough such that said thermal transfer layer has a light transmittance of at least about 30 percent.

9. The thermal transfer layer as recited in claim 7, wherein said thermal transfer layer is comprised of less than about 5 weight percent of carbon black.

10. The thermal transfer layer as recited in claim 7, wherein said thermal transfer layer is comprised of less than about 1 weight percent of carbon black.

11. The thermal transfer layer as recited in claim 7, wherein at least about 90 weight percent of said first taggant is comprised of particles smaller than 15 microns.

12. The thermal transfer medium as recited in claim 11, wherein said first colorant is a pigment.

13. The thermal transfer medium as recited in claim 11, wherein said first colorant is a color-shifting pigment.

14. The thermal transfer medium as recited in claim 11, wherein said first colorant is a dye.

15. The thermal transfer medium as recited in claim 11, wherein said thermal transfer medium is comprised of said thermal transfer layer, a flexible support disposed beneath said thermal transfer layer, and a transferable undercoating layer disposed between said flexible support and said thermal transfer layer.

16. The thermal transfer medium as recited in claim 15, wherein said undercoating layer is comprised of said second taggant, and wherein said second taggant is comprised of a fluorescent substance with has an emission wavelength that differs by at least 50 nanometers from the emission wavelength of said first taggant.

17. The thermal transfer medium as recited in claim 15, wherein said first taggant is an up-shifting phosphor.

18. The thermal transfer medium as recited in claim 17, wherein said first colorant is a pigment.

19. The thermal transfer medium as recited in claim 17, wherein said transferable undercoat layer is comprised of a second taggant.

20. The thermal transfer medium as recited in claim 19, wherein said second taggant is a photochromic substance.

21. The thermal transfer medium as recited in claim 19, wherein said second taggant is a thermochromic substance.

22. The thermal transfer medium as recited in claim 19, wherein said second taggant is a chemochromic substance.

23. The thermal transfer medium as recited in claim 19, wherein said second taggant is a mechanochromic substance.