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US 6,517,239 B1Granted
Time-temperature indicators activated with thermal transfer printing and methods for their production
AssigneeNCR Corporation
InventorsJoseph D. Roth, John C. Rosenbaum
Life of this patent
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Abstract
Time-temperature indicators (TTIs) which are generated by converting indicator compounds from an inactive state to an active state using a thermal transfer printing apparatus are described.
Claims28
A thermal transfer medium, suitable for use in a thermal transfer printing apparatus, comprising at least one thermal transfer layer which contains at least one indicator compound,
- wherein the indicator compound exhibits detectable changes in response to an exposure element and wherein the indicator compound is convertible from an inactive state to an active state by the application of heat from a print head of said thermal transfer printing apparatus and wherein the indicator compound transfers to a receiving substrate with said thermal transfer layer.
A method which comprises:
- providing a thermal transfer medium suitable for use in a thermal transfer printing apparatus comprising at least one thermal transfer layer which contains at least one indicator compound, wherein said indicator compound exhibits detectable changes in response to an exposure element, and wherein the indicator compound is convertible from an inactive state to an active state by the application of heat from a print head of said thermal transfer printing apparatus, and wherein the indicator compound transfers to a receiving substrate with said thermal transfer layer;
- heating the thermal transfer medium in said thermal transfer printing apparatus to soften portions of the thermal transfer layer with said indicator compound and convert at least some of the indicator compound to an active state, and
- transferring softened portions of the thermal transfer layer which contains activated indicator compound to said receiving substrate to form a time-temperature indicator.
A thermal transfer system comprising:
- a thermal transfer medium comprising at least one thermal transfer layer which contains at least one indicator compound,
- a thermal transfer printing apparatus having a print head which transfers thermal transfer layers of thermal transfer media to a receiving substrate,
- one or more receiving substrates, suitable for receiving thermal transfer layers transferred from thermal transfer media by the print head of said thermal transfer printing apparatus,
- wherein the thermal transfer medium is of a size suitable for feeding in the thermal transfer printing apparatus and the thermal transfer layer will transfer to one or more of said receiving substrates in response to the print head of said thermal transfer printing apparatus,
- wherein the indicator compound exhibits detectable changes in response to an exposure element, and wherein the indicator compound is convertible from an inactive state to an active state by the application of heat from the print head of said thermal transfer printing apparatus,
- and wherein the indicator compound is transferred to the receiving substrate with said thermal transfer layer.
3 more elements
A method which comprises:
- providing a thermal transfer medium suitable for use in a thermal transfer printing apparatus comprising at least one thermal transfer layer which contains at least one inactive indicator compound which is activated when transferred to a receiving substrate, wherein said indicator compound exhibits detectable changes in response to an exposure element, and wherein the indicator compound is convertible from an inactive state to an active state by the application of heat from a print head of said thermal transfer printing apparatus, and wherein the indicator compound transfers to the receiving substrate with said thermal transfer layer;
- heating the thermal transfer medium in said thermal transfer printing apparatus to soften portions of the thermal transfer layer with said indicator compound and convert at least some of the indicator compound to an active state, and
- transferring softened portions of the thermal transfer layer which contains activated indicator compound to said receiving substrate to form a time-temperature indicator.
Dependencies are inferred from the claim text.