Thermal paper is a special kind of paper, it has the ability of thermal induction, its printing principle is through the heating effect of the thermal print head, so that the heat-sensitive layer of paper discoloration, so as to achieve the generation of text, images and other content. The size of the thermal paper plays a vital role in a variety of different applications, which include, but are not limited to, receipts, labels, tickets, medical record printing, and so on. In different applications, one chooses the right size of thermal paper according to the specific needs.