Ink Jet Technology

The concept behind inkjets is familiar to most users: ink gets squirted out of nozzles located within the print head, which distribute the ink across the page as it is fed through the printer.

It's less well known, though, that the technology itself can be broken down into two common types: thermal and piezo.

Although both distribute ink in a similar fashion, the difference lies in how they transfer the ink to the page. In thermal inkjets, the nozzles located inside the print head are heated to create a vapor bubble that forces a droplet of ink onto the paper. Due to the nature of the ink transferal method, many manufacturers refer to these types of inkjet printers as bubble jets. Manufactures producing bubble jets include HP, Canon and Lexmark.

In contrast, piezo printers squirt pressurized ink through the nozzles by charging the piezo crystal located behind the nozzles in the print head with electricity. Piezo crystals vibrate when charged with electricity and this, in turn, pulls and then pushes the ink within the nozzle. By varying the strength of the electrical charges, the technology causes different-sized ink droplets to break away from the nozzle. Also called the vibration method, the technology was patented by Epson and is consequently used in its range of inkjet printers.

In practice, there is little difference between piezo and thermal inkjets, and long-held beliefs that piezo printers have more accuracy than thermal printers have petered out.