Time-temperature indicators activated with direct thermal printing and methods for their production
AssigneeNCR Corporation
InventorJoseph D. Roth
Life of this patent
Estimating the term…
Abstract
Recording materials are converted in a direct thermal imaging apparatus to time temperature indicators by exposure to heat from the thermal print head of a direct thermal printer. Methods for converting a recording material to a time temperature indicator comprise heating the recording material with a direct thermal imaging apparatus. The recording material contains an indicator compound which is convertible from an inactive state to an active state when heat is applied thereto by a direct thermal imaging apparatus for less than one second. Time-temperature indicators with active indicator compounds in a printed pattern are formed by a direct thermal imaging apparatus.
Claims26
A recording material comprising a base sheet suitable for feeding into a thermal printer, wherein said thermal printer is suitable for generating a thermal image on thermal paper,
- wherein said recording material has at least one time-temperature indicator (TTI) compound coated on said base sheet or incorporated in said base sheet,
- wherein the indicator compound is coated on the surface of said base sheet or incorporated in the surface of said base sheet so as to be convertible from an inactive state to an active state when heat is applied by said thermal printer
- wherein the indicator compound exhibits detectable changes in response to an exposure element when in an active state, and
- wherein the indicator compound is coated on the base sheet or incorporated in the base sheet in a concentration which permits the recording material to function as a time-temperature indicator when said indicator compound is active,
- and wherein the indicator compound is convertible from an inactive state to an active state in said thermal printer operating at a temperature in the range of 50° C. to 250° C.
A recording material comprising a base sheet suitable for feeding into a thermal printer that is suitable for generating a thermal image on a thermal paper having at least one time-temperature indicator (TTI) compound coated on said base sheet or incorporated in said base sheet wherein the indicator compound is coated on the surface of said base sheet or incorporated in the surface of said base sheet so as to be convertible from an inactive state to an active state when heat is applied by said thermal printer wherein the indicator compound exhibits detectable changes in response to an exposure element when in an active state, and wherein the indicator compound is coated on the base sheet or incorporated in the base sheet in a concentration which permits the recording material to function as a time-temperature indicator when said indicator compound is active wherein the recording material also contains dye components for thermal printing by said thermal printer.
A method which comprises:
- providing a recording material suitable for use in a thermal printer, wherein said thermal printer is suitable for generating a thermal image on a thermal paper,
- wherein said recording material has at least one indicator compound incorporated therein,
- wherein the indicator compound is convertible from an inactive state to an active state when heat is applied thereto within said thermal printer and
- said indicator compound provides detectable changes in color in response to an exposure element when in an active state;
- and
- heating the recording material in said thermal printer to convert at least some of the indicator compound from an inactive state to an active state and form a time-temperature indicator,
- wherein said thermal printer is operated at a temperature in the range of 50° C. to 250° C.
Dependencies are inferred from the claim text.