| CPC G01K 11/12 (2013.01) [B41J 2/375 (2013.01); C09D 11/50 (2013.01); G01K 3/04 (2013.01); G01K 11/16 (2013.01); C09D 5/26 (2013.01); G09F 2003/0211 (2013.01)] | 32 Claims |

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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.
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