Thermal paper

Thermal paper, can be referred as Audit roll, is a special fine paper that is coated with a material formulated to change color when exposed to heat. It is used in thermal printers and particularly in inexpensive or lightweight devices such as adding machines, cash registers, and credit card terminals.When taking hold of a receipt consisting of thermal printing paper for five seconds, roughly 1 μg BPA (0.2–0.6 μg) was transferred to the forefinger and the middle finger if the skin was rather dry, and about ten times more than this if these fingers were wet or very greasy. Exposure to a person who repeatedly touches thermal printer paper for about ten hours per day, such as at a cash register, could reach 71 micrograms per day, which is 42 times less than the present tolerable daily intake (TDI). Thermal paper, can be referred as Audit roll, is a special fine paper that is coated with a material formulated to change color when exposed to heat. It is used in thermal printers and particularly in inexpensive or lightweight devices such as adding machines, cash registers, and credit card terminals. The surface of the paper is coated with a solid-state mixture of a dye and a suitable matrix; a combination of a fluoran leuco dye as an example. When the matrix is heated above its melting point, the dye reacts with the acid, shifts to its colored form, and the changed form is then conserved in a metastable state when the matrix solidifies back quickly enough. The reactant acid in thermal paper is often bisphenol A (BPA).