Thermal Printers

Thermal printers have been on the market for over twenty years. There are many sizes available for various jobs, from a 2.5 inch battery-operated option to a 24-volt sized unit. Numerous occupations employ the use of thermal printers. A thermal printer is a machine that produces a printed image through a process using heat, causing special paper known as thermo chromic paper, commonly known as thermal paper, to transfer an image onto the paper when the page passes over the printing head. Normally the color used in this process is black. Two colors can be used, in which case the second color is usually red. The second color is applied at a slightly different temperature. A similar method called thermal transfer printing is obtained by using a heat sensitive ribbon instead of the paper.

How they Work

A thermal printer is made up of several components. One of the most important is a thermal head that generates the heat that helps the ink to adhere to the paper. A rubber roller, called a plate, feeds the paper through the printer. Pressure is applied to the thermal head so that contact is made with the thermal-sensitive paper to allow the printing process to occur. A controller board helps to control the printer to achieve the finished product. The desired image is sent through the controller board to control the printer. Different fonts and images can be embedded into the memory of the controller board. Many options are available so the user can create many different images. Many thermal printers available display alert sensors to indicate many different problems which may arise. These sensors are controlled by the controller board and can indicate if the paper is low or if a door is open on the printer.

The paper used in this process for thermal printers becomes saturated with a combination of solid dye and a compatible medium. As an example, Flouran Leuco dye and Octadecylphosphonic acid cause a chemical reaction which, in turn, and when heated above the melting point, causes the dye to take on a color, usually black. At this high temperature the ink combination is then applied to the paper. This process is called thermochromism.

Recent Advances

The first and early types of thermal printers, using early styles of thermal paper, suffered from the problem that the paper was very sensitive to friction, heat and abrasion, which led to the darkening of the paper over time. Light and water would cause the ink to fade. The technology of this process has advanced to expand the longevity of the printed product which can now, in most cases, last up to fifty years. Thermal printers are found to be faster and quieter than ink dot printers, which makes them perfect for offices and businesses.