How thermal printers work
The working principle of a thermal printer is that a semiconductor heating element is installed on the print head. After the print head is heated and contacts the thermal printing paper, the required pattern can be printed. The principle is similar to that of a thermal fax machine. The image is created by heating, causing a chemical reaction in the film. This chemical reaction takes place at a certain temperature. High temperatures speed up this chemical reaction. When the temperature is below 60°C, the paper takes a long time, even several years, to turn dark; when the temperature is 200°C, this reaction will be completed in a few microseconds.
The thermal printer selectively heats certain locations on the thermal paper, thereby producing corresponding graphics. Heating is provided by a small electronic heater on the print head that is in contact with the heat-sensitive material. The heaters are arranged in the form of square dots or strips and are logically controlled by the printer. When driven, a pattern corresponding to the heating element is produced on the thermal paper. The same logic circuit that controls the heating element also controls the paper feed, allowing graphics to be printed across the entire label or paper.
The most common thermal printer uses a fixed print head with a heated dot matrix. The print head is equipped with 320 square dots, each dot is 0.25mm×0.25mm. Using this dot matrix, the printer can print dots on any position on the thermal paper. This technology has been used in paper printers and label printers.
