Thermal label printer is that a semiconductor heating element is installed on the print head, and the print head can print out the required pattern after heating and contacting the thermal printing paper. Its principle is similar to that of a thermal fax machine. The image is created by heating the membrane to create a chemical reaction. This thermal label printer chemical reaction takes place at a certain temperature. High temperatures speed up the chemical reaction. When the temperature is below 60℃, it takes quite a long time, even years, for paper to become dark. At 200℃, the reaction takes place in a matter of microseconds.