Small receipt paper is the most common label of thermal printing paper, which is generally white. Thermal label paper is a special kind of high-grade paper. Coating some chemical raw materials on paper can make the paper change color due to heating, without ink or printing ink. Thermal paper can be used as a thermal printer, which is called thermal paper printer, receipt paper printer, bill printer and so on.

The basic principle of thermal printing paper is to coat a common paper base with granular powder, which is composed of colorless dye phenol or other acidic substances, and the film is melted in the middle. On the premise of heating, the film melts and the powder is mixed to form a coloring reaction. Generally speaking, the color handwriting on thermal printing paper is unstable and easy to fade, which makes it difficult to identify the contents of the document, which is also the reason why supermarket receipts often appear illegible.