Thermal printers print on paper by heating the ink and pressing it against the paper. A thermometer tells you what temperature to heat the paper and the length of time to heat the paper. A thermal printer is not an electrostatic printer, laser printer, or inkjet printer. In order to make the heated image permanent on the paper, the paper must be pressed firmly into place. The paper must stay on the paper drum until the print is complete. To ensure the proper alignment of the paper, thermal printers use a guide roller and paper path.
Introduction
The first thermal printers used a small glass bulb to heat the paper. The glass bulb heated the paper through conduction. The glass bulb heated the paper and the paper then cooled. The paper had to be transferred to another part of the machine after printing. This type of thermal printer was the first kind of thermal printer.
In the early 1970s, a new thermal printer was developed that used a continuous roll of paper. The paper was continuously fed through the machine. The continuous roll of paper helped reduce jamming.
Thermal printers were first sold commercially in 1971.
The development of thermal printers did not start with the first commercial model. The first thermal printers used a glass bulb to heat the paper.
How do thermal printers work
Thermal printers use a small electric heater to heat the paper. A thermistor located on the heater reads the temperature of the paper. The thermistor sends a signal to a controller board. The controller board tells the heater to turn on and off at the right temperature and time.
In order to print, the paper is placed on a paper drum. The paper drum is covered by a protective cover. The paper drum has a metal base. The cover has a flexible plastic top. The plastic top of the cover slides over the metal base.
As the paper drum rotates, a paper transport roller pulls the paper from the paper drum. The paper is then pushed to a paper path by a paper guide roller. The paper moves down to the paper outlet. When the paper is out of the machine, a paper take-up roller pulls the paper back into the paper drum.
As the paper drum starts to rotate, the cover of the paper drum moves along with it. The plastic cover stops at a spot on the paper drum. The paper drum has a slot cut in the center of the cover. The slot is designed to hold a thin piece of plastic. The plastic fits snugly inside the slot. As the cover travels around the paper drum, the plastic piece slides in and out of the slot. When the plastic piece is in the center of the slot, the slot prevents the plastic piece from getting caught on the rotating paper drum.
When the plastic piece is out of the slot, the plastic piece is pulled by gravity. Gravity pulls the plastic piece out of the slot. The plastic piece slides along the paper drum to the paper outlet.