The working principle of color thermal label paper

The working principle of color thermal label paper is very simple, it is based on physical and chemical reactions. Let me explain:

Leuco dye: A special leuco dye is used in color thermal label paper. The dye itself is colorless, and at room temperature, thermal paper looks no different from ordinary paper.

Temperature change triggers reaction: Once the temperature rises, the dark dye and the acidic substance successively melt into a liquid. At this point, molecules that can move freely meet and react immediately. So the white paper soon showed color. This is the reason why thermal paper is named - only the temperature is high enough to make the paper change color.

To summarize, when we print with thermal paper, the ink is not stored in the printer, but is already covered on the paper. Thermal paper needs a special printer, which is a thermal printer. If you have the opportunity to disassemble the thermal printer, you will find that its internal structure is very simple: there is no ink cartridge, the main components are the drum and print head. The thermal paper used to print receipts is usually made in rolls. When a roll of thermal paper is put into the printer, it will be driven forward by the roller and contact with the print head to achieve the printing effect