A thermal transfer printer is a non-impact printer that uses heat to register an impression on paper. A thermal transfer printer has a printhead containing many small resistive heating pins that on contact, depending on the type of thermal transfer printer, melt wax-based ink onto ordinary paper or burn dots onto special coated paper. A microprocessor determines which individual heating pins are heated to produce the printed image. The printhead spans the entire width of the paper or medium to be printed on. Thermal transfer printers are popular for printing bar codes, labels, price tags, and other specialty print jobs. There are two types of thermal transfer printers: direct thermal and thermal wax transfer.
Direct thermal: The direct thermal printer prints the image by burning dots onto coated paper as it passes over the heated printhead. Direct thermal printers do not use ribbons. Early fax machines used direct thermal printing.
Thermal wax transfer: This type of printer uses a thermal transfer ribbon that contains wax-based ink. Heat is applied to the ribbon using a thermal printhead that melts the ink transferring it to the paper where it is permanent after it cools. A typical thermal transfer ribbon consists of three layers: the base material, the heat melting ink, and the coating on the print side of the base material. The coating and base material help keep ink from adhering to the printhead which can cause poor print quality. Monochrome and color thermal transfer ribbons are available. It is recommended that the printhead be cleaned between each ribbon change with a cotton swab and isopropyl alcohol.
The cost of a thermal transfer printer varies depending on the size of the printer and the features included. The cost of consumables such as paper, ribbons, and printheads is about the same for both types of printers. The print quality depends on the printer, the ribbon, the paper, and the environment such as where the printer is stored, the temperature, and the humidity.