This works in a similar way to Ink Jet printers, but instead heat the ink in the nozzle, which forms bubbles, and forces the ink out on to the page.
A bubble-jet printer is a type of ink-jet printer. In a bubble jet printer, tiny resistors create heat which vaporises ink to create a bubble. This causes a droplet to form and eject from the print head. A typical bubble-jet print head may have 64 or 128 tiny nozzles, and all of them can fire a droplet simultaneously.
bubble-jet printer noun a kind of ink-jet printer