Why do supermarkets use thermal paper to print receipts, and why not use a printer?

You mean a laser printer or an inkjet printer,

First, because of the cost, the thermal paper printer has low cost and low maintenance cost. There is no need to add ink like an inkjet printer, change the print head, or add toner like a laser printer, and the power consumption is many times lower.

Second, the stability is good. After all, the working principle is simple, the mechanical structure of circuit design is simple, it is not easy to break down and the system will not collapse.

Third, the occupied space is small. Don't laugh at this answer. It would be embarrassing to put the laser printer in such a small place as the supermarket checkout counter.