How does a thermal printer produce printed output?

@gregory_keeling 

A thermal printer produces printed output using heat and special thermal paper. Here's the basic process:

1. Paper loading: First, the thermal paper is loaded into the printer. It usually comes in the form of a roll or sheets.
2. Heating elements: The thermal printer contains an array of tiny heating elements called thermal print heads. These heads are responsible for generating heat.
3. Heat transfer: When the printer receives a printing command, it activates specific heating elements corresponding to the desired pattern. These selected heating elements heat up rapidly, generating heat on the surface of the thermal paper.
4. Thermosensitive layer: The thermal paper used in thermal printers has a thermosensitive layer containing microcapsules or a special chemical coating. This layer reacts to the heat by changing its color.
5. Color development: When heated, the thermosensitive layer undergoes a chemical reaction. In the case of direct thermal printers, the microcapsules burst and release a dye, which then reacts with a developer chemical on the paper surface to produce the desired color. In the case of thermal transfer printers, the heat causes the chemical coating to transfer onto the paper, resulting in color development.
6. Printout: As the thermal print heads move across the thermal paper, different heating elements are activated to produce the desired pattern or text by selectively heating specific areas. The heat triggers the color development process, and the result is a visible printout on the thermal paper.

Thermal printers are known for their fast printing speed, low noise level, and low maintenance requirements, making them widely used in applications like retail receipts, barcode labels, tickets, and more.