How do Thermal Printers work?

A thermal printer or sometimes called a direct thermal printer produces a printed image be selectively heating coated thermochromic paper, or thermal paper as it is more commonly known. The thermal print head itself is bascially a row of heating elements that when a electrical current is supplied to the element it products heat. When the paper passes over the thermal print head the coating turns black in the areas where it is heated, producing the desired image. Thermal printers produce excellent text, graphic and barcodes at very fast speeds. The only consumable for thermal printers is the paper roll. Care must be taken in selecting your paper roll grade; low cost papers tend to be very coarse and can act like sand paper on the print head drastically reducing the head life. Also, an industry myth is that thermal paper will lose its image over time, this may have been the case back in the thermal printings early days however with the improvement in the paper technology, papers can now be stored for up to 25 years.