Thermal sensitive coatings or protective coatings that affect the quality of thermal paper.
Thermal sensitive printing paper is usually divided into three layers, the bottom is the paper base, the second layer is the thermal coating, the third layer is the protective layer and the paper is printed, which mainly affects the quality of the thermal sensitive coating or protective layer.
If the coating of the thermal sensitive paper is not uniform, it will lead to deep color in some places, some places are light, and the quality of printing is obviously reduced. If the chemical formula of the thermal coating is not reasonable, the storage time of the printing paper will be very short, and the good printing paper can be stored (at normal temperature, avoid direct sunlight). In the past 5 years, there are more long-term thermal paper that can be kept for 10 years. But if the formulation of the thermal coating is unreasonable, it may only be kept for several months.
The protective coating is also critical for the storage time after printing. It can absorb a part of the light that causes the chemical reaction of the thermal coating, slow down the deterioration of the printing paper and protect the printer's thermal elements from damage, but if the protection of the coating is not uniform, it will not only greatly reduce the protection of the thermal coating, but also greatly reduce the protection of the thermal coating. During the printing process, the small particles of protective coating will fall off, and the heat sensitive elements of the friction printer will cause damage to the printed thermal element.