When An ATM Receipt is Exposed to Sunshine, Why Does the Print Fade?

 

A quick printing process known as thermal printing is used to create ATM receipts (recently, even bus tickets have been issued with the same kind of print-outs). It works on the theory of thermochromism, which is the difference of color caused by heating. Thermal printing works by imprinting with print heads on a particular kind of paper roll (found in ATMs and vending machines) that is coated with organic dyes and waxes.

The paper is a special thermal paper that has been impregnated with a pigment and an appropriate matrix, such as fluoran leuco dye and octadecylphosphonic acid.When the print-head, which is made up of a standard series of minuscule heating elements, receives the printing signal, it increases the temperature to the organic coating's melting point, causing a print impression on the paper roll via the thermochromism mechanism. Normally, black-color printouts are obtained, but by controlling the temperature of print heads, red printouts can also be obtained.

Also when kept at room temperature, these printouts are prone to fading over time. When warm or brought close to a candle flame, as well as when exposed to the rays of the sun, this effect is amplified. Continuous exposure to sunlight produces a significant amount of heat, well past the melting point of these coatings, causing permanent harm to the chemical structure of the coating, ultimately resulting in shading or disappearance of the printed matter. You can find a good ATM paper roll manufacturers in India.