When choosing thermal paper, pay more attention to the appearance of the paper. From the color, we can distinguish the quality of its protective coating and thermal coating to a certain extent. If the paper is very white, it means that the protective coating and thermal coating of the paper are unreasonable, and it is likely that too much phosphor is added. If the paper is slightly green, then its quality should be better. If the paper looks smooth and flat, the thermal paper coating is more uniform, otherwise, it means that the paper coating is uneven, which will seriously affect the printing effect. At the same time, if the paper seems to have strong reflected light, it is also due to the addition of too much phosphor, it is best not to choose such thermal paper.

Sunlight contrast identification:
This method is very simple, just apply different printed papers with the same highlighter and put them in the sun to expose them. Eventually they will all turn black. The longer it takes to turn black, the storage time of this thermal paper The longer.

Fire grill:
In fact, the method of fire roasting and sun exposure are similar, the principle is similar. You can use a lighter to slowly heat the back of the paper. The color of the paper will change with heating. If the final color is brown, it means that the thermal formula is not reasonable and the storage time may be shorter; if the paper is visible on the small Stripes or scattered color patches indicate uneven coating. On the contrary, the thermal paper with better quality will eventually appear black-green after heating, and the color block is uniform, and the color gradually fades from the center of the heating to the surroundings.