A printer that uses heat to transfer an impression onto paper. There are two kinds of thermal printers:
hermal wax transfer: a printer that adheres a wax-based ink onto paper. A thermal printhead melts wax-based ink from the transfer ribbon onto the paper. When cool, the wax is permanent. This type of thermal printer uses an equivalent panel of ink for each page to be printed, no matter if a full page or only one line of print is transferred. Monochrome printers have a black page for each page to be printed, while color printers have either three (CMY) or four (CMYK) colored panels for each page. Unlike thermal dye transfer printers , also called dye sublimation printers, these printers print images as dots, which means that images must be dithered first. As a result, images are not quite photo-realistic, although they are very good. The big advantages of these printers over thermal dye transfer printers are that they don't require special paper and they are faster.
direct thermal: a printer that prints the image by burning dots onto coated paper when the paper passes over a line of heating elements. Early fax machines used direct thermal printing.