What is the principle of thermal paper?
Commonly used as colorless dyes, mainly: three, benzene, alkyl benzene phthalocyanine system of crystal violet lactone (CVL), fluoranthene system, colorless benzene methylene blue (BLMB) or spiro system and other substances. Commonly used as chromogenic agent mainly: para hydroxy benzoic acid and its esters (PHBB, PHB), salicylic acid, 2,4-, two hydroxy benzoic acid, or aromatic sulfone and other substances.
When the heat sensitive paper is placed in the environment above 70 degrees Celsius, the thermal sensitive coating starts to change color. The reasons for its discoloration are also discussed in terms of its constituents.There are two kinds of heat sensitive components in thermal paper coating: one is colorless or implicit color, and the other is color developing agent. This type of thermal sensitive paper is also known as "double differentiation" type thermal recording paper.
Thermal paper is a kind of special coated paper, its appearance is similar to that of ordinary white paper. Thermal paper surface is smooth, is composed of ordinary paper as base paper, coated with a layer of thermosensitive coloring layer above, are painted on the side surface of the ordinary paper, hair layer is composed of adhesive, chromogenic agent, dye (or colorless leuco dye no, through the micro capsule) to be separated from the chemical reaction in a latent state. When the print head thermal paper encountered fever, chromogenic agent and printing of the print head is colorless dye chemical reaction and color, graphic form.
When the heat sensitive paper is heated, the colorless dye and the coloring agent react chemically to produce a color, so when the heat sensitive paper is received on the facsimile machine, the signal is printed or directly printed with a thermal printer, and the pictures and the words are displayed. Because there are many varieties used as a colorless dye, the colors appear different. They are blue, purple, black and so on.
