What are the functions of thermal paper protective coating and thermal coating?

Thermal printing paper is generally divided into three layers, the bottom layer is the paper base, the second layer is the thermal coating, and the third layer is the protective layer. The thermal coating or protective layer mainly affects its quality. Uneven coating will result in dark color in some places and light color in some places during printing, and the printing quality will be obviously reduced. The thermal paper can be stored for 5 years after printing (under the conditions of room temperature and avoid direct sunlight), and now there are long-term thermal paper that can be stored for 10 years, but if the formula of the thermal coating is unreasonable, it may only be Save for a few months.

Thermal paper quality identification:

1. Appearance:If the paper is very white, it means that the protective coating and thermal coating of the paper are unreasonable, and too much phosphor is added, and the better paper should be slightly greenish. The paper does not have a high finish or looks uneven, indicating that the coating of the paper is uneven. If the paper seems to reflect light strongly, too much phosphor has been added, and the quality is not good.

2. Fire roasting:The method of roasting with fire is also very simple. Use a lighter to heat the back of the paper. If the color on the paper is brown after heating, it means that the thermal formula is not reasonable, and the storage time may be relatively short. Small streaks or uneven color patches on the black part of the paper indicate an uneven coating. Better quality paper should be dark-green (with a hint of green) after heating, and the color patches are uniform, gradually fading from the center to the periphery.

3. Comparison and identification of sunlight exposure:apply the printed paper with a highlighter and place it in the sun (this can speed up the reaction of the heat-sensitive coating to light), which kind of paper turns black faster, indicating that the longer it can be stored. short.

The thermal paper protective coating is also critical to the storage time after printing. It can absorb part of the light that causes the thermal coating to react chemically, slow down the deterioration of the printing paper, and protect the thermal components of the printer from damage, but If the protective coating is not uniform, it will not only greatly reduce the protection of the thermal coating, but even the fine particles of the protective coating will fall off during the printing process, rubbing the thermal components of the printer, resulting in damage to the thermal components of the printing.