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Principle of thermal printer operation. Thermal print method

Thermal printers work on the principle of thermal print consisting in use of special thermal paper that changes the color by heat. Thermal paper is a usual paper sheet covered with very thin, in several microns, thermosensitive film. Under the impact of heat, the film melts, while coloring matter and reagent that has been in the solid state enter into a reaction. In order the paper changed its color, it should be heated up to 150-200 °С.

An image on the paper is formed by a number of semiconducting heating elements that are placed perpendicularly to the paper feed direction. When feeding the voltage to the thermoelement, the corresponding area of the media gets heated and then consequently changes its color and darkens. The paper is stretched out along the line of thermoelements, which quickly get heated and then cold, thus leaving marks in the necessary places of the tape. The image that will be typed by the printer is made of such marks arranged by lines.

Thermal printers have many advantages. They are characterized by the low level of operating costs due to the simple construction of highest reliability level. Besides, there is no necessity of regular maintenance service. Thermal paper is the only type of consumables necessary for thermal printer operation. At that, both sheet and roll thermal paper can be used.

Among the advantages of thermal printers are the absence of paper dust and noiselessness of operation. They also support the cheque tape economy mode. Cheque print can be done arbitrary small, and cheques themselves can be small. One more important moment that should be paid attention to is the fact that an image on thermal paper is water resistant.

Among thermal printers disadvantages are comparatively low according to contemporary standards resolution (of about 200 dpi), as well as low printing speed. Besides, thermal printers allow getting only monochrome images and have limited halftone reproduction. Due to this reason, images are usually of black or blue color and the sphere of thermal printers application is limited to printing of text and simple graphic information.

High reliability, low print cost and unpretentiousness of printing mechanisms make these devices ideal in the exploitation process.

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