What it is Thermal printer paper
Thermal paper is a special kind of coated paper, and its appearance is similar to ordinary white paper. The surface of heat-sensitive paper is smooth, and ordinary paper is used as the paper base. A layer of heat-sensitive coloring layer is coated on the surface of ordinary paper. (Called leuco dye), which is not separated by microcapsules, and the chemical reaction is in a "latent" state. When the thermal paper encounters a hot print head, the developer and leuco dye where the print head prints undergo a chemical reaction to change color and form graphics.
When the thermal paper is placed in an environment above 70 ° C, the thermal coating begins to change color. The reason for its discoloration also starts from its composition. There are two main types of thermal sensitive components in thermal paper coatings: one is a leuco dye or leuco dye; the other is a color developer. This type of thermal paper is also called a two-component chemical type thermal recording paper.
Commonly used as colorless dyes are: crystal violet lactone (CVL), trifluoroalkyl phthalide system, fluorane system, colorless benzoylmethylene blue (BLMB) or spiropyran system. Commonly used as a developer are para-hydroxybenzoic acid and its esters (PHBB, PHB), salicylic acid, 2,4-dihydroxybenzoic acid or aromatic sulfone.
After the thermal paper is exposed to heat, the colorless dye and the developer react with each other to produce a color. When the thermal paper is used to receive a signal on a facsimile machine and printed directly or printed with a thermal printer, the graphics are displayed. Since there are many types used as leuco dyes, the colors of handwritings displayed are different, such as blue, fuchsia, and black.