Semi-irreversible temperature exposure sensor customizable by thermal printer

Patent metadata

Field	Value
Publication number	US-12332121-B2
Application number	US-202117498371-A
Country	US
Kind code	B2
Filing date	Oct 11, 2021
Priority date	Oct 11, 2021
Publication date	Jun 17, 2025
Grant date	Jun 17, 2025

Abstract

A customizable temperature exposure indicator and methods for making the same are disclosed. The temperature exposure indicator includes a substrate, a printing region of the substrate forming a heat sensitive media that is configured to darken when it is heated by a thermal printhead, the darkening being permanent with respect to subsequent cooling of the media; at least one memory thermochromic composition provided on an indicator region of the substrate, the thermochromic composition is configured to have high temperature color state when it is heated above a high temperature threshold, and to remain in the high temperature color state until it is cooled below a low temperature threshold, the thermochromic composition is configured to have a low temperature color state when it is cooled below the low temperature threshold and to maintain the low temperature threshold until it is heated above the high temperature threshold.

First claim

The invention claimed is:

1. A temperature exposure indicator, comprising:
a substrate, a printing region of the substrate forming a heat sensitive direct thermal print media that is configured to darken when it is heated by a direct thermal printer printhead, the darkening being permanent with respect to subsequent cooling of the media;
at least one memory thermochromic composition provided on an indicator region of the substrate,
wherein the thermochromic composition is configured to have high temperature color state when it is heated above a high temperature threshold, and to remain in the high temperature color state until it is cooled below a low temperature threshold,
wherein the thermochromic composition is configured to have a low temperature color state when it is cooled below the low temperature threshold and to maintain the low temperature color state until it is heated above the high temperature threshold.

2. The temperature exposure indicator of claim 1 , wherein the darkened portion of the media maintains its dark appearance below the low temperature threshold.

3. The temperature exposure indicator of claim 1 , wherein a portion of the indicator region is exposed to the high temperature threshold using a direct thermal print head placing the thermochromic composition in the portion of the indicator region in the high temperature color state, while a remaining portion of the thermochromic composition is left in the low temperature color state, thereby providing a human readable indicia within the indicator region.

4. The temperature exposure indicator of claim 3 , wherein the high temperature color state of the thermochromic composition is invisible to the human eye, while the low temperature color state is visible or the high temperature color state of the thermochromic composition is visible to the human eye, while the low temperature color state is invisible.

5. The temperature exposure indicator of claim 1 , wherein a portion of the indicator region is exposed to the low temperature threshold using a cooling agent, while a remaining portion of the thermochromic composition is left in the high color temperature state, thereby providing a human readable indicia within the indicator region.

6. The temperature exposure indicator of claim 5 , wherein the high temperature state of the thermochromic composition is invisible to the human eye, while the low temperature state is visible or the high temperature color state of the thermochromic composition is visible to the human eye, while the low temperature color state is invisible.

7. The temperature exposure indicator of claim 1 , wherein the visual characteristics of the memory thermochromic composition in the high temperature color state may vary based on temperature hysteresis of the composition.

8. The temperature exposure indicator of claim 1 , wherein the visual characteristics of the memory thermochromic composition in the low temperature color state may vary based on temperature hysteresis of the composition.

9. The temperature exposure indicator of claim 1 , wherein the indicator region and the printing region are non-overlapping.

10. The temperature exposure indicator of claim 1 , wherein the indicator region and the printing region are overlapping.

11. The temperature exposure indicator of claim 10 , wherein the printing region occupies the entire face of the substrate.

12. The temperature exposure indicator of claim 1 , wherein the indicator region is contiguous.

13. The temperature exposure indicator of claim 1 , wherein the high temperature threshold temperature is in a range from 5° C. to 100° C.

14. The temperature exposure indicator of claim 1 , wherein the low temperature threshold temperature is in a range from −30° C. to 20° C.

15. The temperature exposure indicator of claim 1 , wherein the thermochromic composition comprises at least one of (i) leuco dye (ii) liquid crystal; (iii) wax; (iv) micro-encapsulated dye; (v) an ester; (vi) an alkane; (vii) an organic polymer; (viii) an inorganic material.

16. The temperature exposure indicator of claim 1 , wherein the substrate further comprises at least of one (i) paper; (ii) polyester; (iii) nylon; (iv) vinyl; (v) other synthetic polymers.

17. The temperature exposure indicator of claim 1 , wherein the thermochromic composition is configured to provide multiple color states, visible to the human eye when the temperature exposure indicator is exposed to a range of threshold temperatures.

18. The temperature exposure indicator of claim 1 , wherein multiple thermochromic compositions are provided on the substrate, each composition having a respective low temperature threshold and respective low temperature color state, or each composition have a respective high temperature threshold and a respective high temperature color state.

19. The temperature exposure indicator of claim 1 , wherein the indicator region overlays at least a portion of a bar code symbol that is readable by an optical scanning device, wherein the visual indication provided by the thermochromic composition affects the appearance of the bar code, and wherein the changed appearance of the indicator region provides a different signal to the optical scanning device.

20. The temperature exposure indicator of claim 19 , wherein the bar code symbol is printed and the indicator is placed in the high temperature color state with the same printing operation.

21. The temperature exposure indicator of claim 1 , wherein the substrate includes printed information identifying the indicator region.

22. A method of creating a descending temperature indicator, the method comprising:
receiving a media having a direct thermal print region that darkens when it is heated by a direct thermal printer thermal printhead, the darkening being permanent with respect to subsequent cooling of the media, the media also having an indicator region with a memory thermochromic composition provided on the media, the thermochromic composition configured to have a high temperature color state when it is heated above a high temperature threshold, and to remain in the high temperature color state until it is cooled below a low temperature threshold, and a low temperature color state when it is cooled below a low temperature threshold and to maintain the low temperature color state until it is heated above the high temperature threshold, wherein the media is provided with the thermochromic composition in the low temperature color state,
printing indicia on the media with a direct thermal printer in the print region;
placing a portion of the indicator region into the high temperature color state using the direct thermal printer.

23. The method of claim 22 , further comprising leaving a second portion of the indicator region in the low temperature color state when the media is printed, so that the combination of the first and second portion of the thermochromic composition forms a human readable indicia indicating the indicator has not been exposed to a temperature below the low temperature threshold.

24. The method of claim 22 , wherein the indicia changes or disappears when the indicator is exposed to a temperature below the low temperature threshold, and is configured to indicate that the indicator has been exposed to a temperature below the low temperature threshold.

25. The method of claim 22 , wherein the high temperature threshold temperature is in a range from 5° C. to

Assignees

• Temptime Corp

Inventors

• Hofer Gene A
• Abdo Mohannad
• Smith Marielle K
• Harding Arianna E

Classifications

• G09F2003/0211

  Transfer or thermo-sensitive · CPC title

• C09D5/26

  Thermosensitive paints · CPC title

• C09D11/50

  Sympathetic, colour changing or similar inks · CPC title

• G01K11/16 Primary

  of organic materials · CPC title

• G01K3/04 Primary

  in respect of time · CPC title