Thermal printers

A thermal printer uses temperature sensitive dye and paper to create hard copy text and images. Some of the thermal printers generate only black-and-white images, while others render full color. Thermal printers are frequently preferred by traveling executives  who use portable computers, as these printers are physically small and light. A simple gray scale thermal printer employs special paper which darkens when it becomes hot. The print mechanism works like that of a dot-matrix printer. But rather than the print head pressing ink onto the page, the pins in print mechanism are heated, and they cause the paper to darken.

A color thermal printer uses thick, heat-sensitive dyes of the primary pigments: magenta (pinkish red), yellow, and cyan (bluish green). At times black dye is also used, although it is obtained by combining large, equal amounts of primary pigments. The print head uses heat to liquefy the dye, so it bleeds onto paper. This is done for every color of the pigment separately. There are 3 separate, overlapping images produced, one for each primary pigment.

Some, if not most, the thermal printouts fade after awhile. Have you pulled out an old ever store receipt and found that it was washed out or blank? Thermal printers can be convenient in a pinch, but you should be aware that they are having this problem—and it is not restricted to old machines. Actually, stores and even some post offices seem to be installing brand new printers with this feature more. If you are keeping a receipt for tax purposes or for the proof of purchase and you notice that it has been printed on thermal paper, go to a print shop and make a photocopy of receipt right away. How can you recognize the thermal printout? The paper curls up when it is fresh out of machine.