Thermal printers are cool… or, uh, warm actually. They use heat to make images, so they never need ink and they print on receipt rolls. The thermal printer available from Adafruit is a particularly tasty example, as it comes fully documented for the budding hacker. [Ed] is one such person, who set about writing his own driver to use the hardware with Linux on a Raspberry Pi.

The project came about as [Ed] didn’t like the halftone output from the standard Adafruit CUPS driver. Thus, a dithering-capable driver was needed instead.

https://deathandthepenguinblog.wordpress.com/2019/12/08/adafruit-mini-thermal-printer-part-1-getting-better-pictures/