Thermal paper billing roll is a type of paper that is used in thermal printers. It is coated with a special chemical that changes color when heated. The heat is generated by the printer s thermal print head. The heat causes the chemical to react, turning the paper black or blue. Thermal paper is used for many applications, including printing receipts, labels, tickets and more. It is also used in fax machines and cash registers. Thermal paper is available in a variety of sizes and types.