In every transaction, payment, and order, there is almost always the use of a receipt to record the purchase. If inspected closely, a receipt is not entirely made of regular cotton paper and, most commonly, not the usual ink. Receipts are not smudged but can fade over time. Thermal receipt paper uses no ink.
Thermal paper is used by a chemical reaction caused by heat. Thermal paper has between 5 to 6 layers to create this effect.
