A printer that uses heat to transfer an impression onto paper. There are two kinds of thermal printers:
thermal wax transfer: a printer that adheres a wax-based ink onto paper. A thermal printhead melts wax-based ink from the transfer ribbon onto the paper. When cool, the wax is permanent. This type of thermal printer uses an equivalent panel of ink for each page to be printed, no matter if a full page or only one line of print is transferred. Monochrome printers have a black page for each page to be printed, while color printers have either three (CMY) or four (CMYK) colored panels for each page. Unlike thermal dye transfer printers , also called dye sublimation printers, these printers print images as dots, which means that images must be dithered first. As a result, images are not quite photo-realistic, although they are very good. The big advantages of these printers over thermal dye transfer printers are that they don't require special paper and they are faster.
direct thermal: a printer that prints the image by burning dots onto coated paper when the paper passes over a line of heating elements. Early fax machines used direct thermal printing.
Thermal printing (or direct thermal printing) is a digital printing process which produces a printed image by selectively heating coated thermochromic paper, or thermal paper as it is commonly known, when the paper passes over the thermal print head. The coating turns black in the areas where it is heated, producing an image. Two-color direct thermal printers can print both black and an additional color (often red) by applying heat at two different temperatures.
A thermal printer comprises these key components:
- Thermal head: generates heat; prints on paper
- Platen: a rubber roller that feeds paper
- Spring: applies pressure to the thermal head, causing it to contact the thermosensitive paper
- Controller boards: for controlling the mechanism
Thermal printers print more quietly and usually faster than impact dot matrix printers. They are also smaller, lighter and consume less power, making them ideal for portable and retail applications. Roll-based printers can be rapidly refilled. Commercial applications of thermal printers include filling station pumps, information kiosks, point of sale systems, voucher printers in slot machines, print on demand labels for shipping and products, and for recording live rhythm strips on hospital cardiac monitors.
How Do Thermal Printers Work?
Your average home user will probably never own a thermal printer. One of today’s primary uses of thermal printers are in businesses or stores that need a POS (point of sale) receipt printer. Some offices may have thermal technology in their fax machine or MFP.
Thermal printers work in one of two ways, for older models heat sensitive paper is used by placing a roll in a container inside the machine and the end of that roll is stuck into a slot. The heat that has built up in the machine reacts with the heat-sensitive paper and the pigments transfer the image to the sheet.
For newer machines, they use ribbon printer cartridges. Inside of the ribbon cartridge there is a waxy material stored inside. When the printer is in use, paper is fed through the a slot located between the print head and a roller and the heat then melts the substance and sticks it onto the paper.
Despite their reputations as solely special use printers, thermal printing does have some distinct advantages. The first advantage is in the price; thermal printers are fairly inexpensive. Second, thermal printers by and large are easy to use. Usually to run a thermal printer it is just a combination of a few buttons and that’s all. A third advantage is that they are quiet printers so they won’t disturb customers or office co-workers.
Others will argue that the disadvantages outweigh the advantages. For one thing, thermal printers are not extremely efficient when it comes to using ink. Because these machines rely on heat to operate, if the machine becomes too hot while in use more ink will come out. This ties into the second problem which is prints that are not always precise. Thermal prints are prone to smudges, even from the heat given off by a person’s fingers can trigger a reaction from the paper. The third disadvantage with thermal printers is the fact that they are almost exclusively monochrome printers. The majority of the ink used with thermal printers is carbon pigmented ink which does not work well with color. For thermal printers to use colors, they utilize more wax based cartridges. The final disadvantage of thermal printers is also related to heat. The high heat used in the printing process can be harmful to the printhead, costing owners money to repair the machine when it breaks down.