10 сентября, 2015 
Malyar 6.4.1.2. Background
Thermosensitive recording paper was introduced by the National Cash Register Company in 1968. The chemistry employed is essentially the same as that for carbonless papers, i. e., color-formation reaction between leuco dye and coreactant, though thermosensitive recording papers require certain unique leuco dyes and coreactants. Thermosensitive recording papers generally consist of a single-sheet system in contrast with the two-sheet system for carbonless copying papers. The surface of the sheet has a thermosensitive layer comprising leuco dye and coreactant as essential color-forming components together with several additives. A cross-sectional view of the structure is shown in Figure 6.8.
The thermosensitive recording paper itself is white like a plain sheet of paper. With the application of heat by means of a thermal pen or thermal head, the color-forming components in the thermosensitive layer are brought into reactive contact in the area delineated by the heat pattern resulting in a distinct image.
The color-forming mechanism is simple and direct, only requiring heat application, and the recording equipment is free from maintenance, highly reliable, and less expensive. Thermosensitive recording papers can be used
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^Thermal head q Colored image s’ |
Leuco dye Co-reactant |
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— Thermo-sensitive layer |
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Figure 6.8. Structure of thermosensitive recording paper. |
Substrate
for various purposes. These include facsimile, medical instruments such as electrocardiograph, spectrophotometer, printer, and video printer. Today, the demand of thermosensitive recording paper for facsimile is 70% or more in total consumption of 300,000 tons worldwide.
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