For home users and small businesses inkjet printers are predominant as they are usually inexpensive, reasonable fast, quiet and generally give a good quality of printout.  Among many contributors, Hewlett Packard, Epson and Canon can claim a substantial share of credit for the development of the modern inkjet printer.

Ink jet printers use one of three main technologies: thermal, piezoelectric, and continuous which we’ll take a look at below:

Thermal Ink Jet
With Epson being a notable exception most consumer inkjet printers work by having a print cartridge with a number of tiny chambers which are electrically heated to induce a steam explosion in the chamber which forms a bubble.  This bubble projects a droplet of ink on to the paper and this method has resulted in Canon naming many of their series of printers ‘Bubblejet’

Once the ink has been propelled on to the paper the surface tension of the ink pulls another droplet of ink in to the chamber in preparation for this one to be transferred to the paper.

The ink used is usually water-based, pigment-based or dye-based and please note that this is not the same thing as a thermal printer which is often found on some fax machines and ATM’s.

Piezoelectric Ink Jet
All Epson printers and most commercial inkjet printers use a piezoelectric crystal in each nozzle instead of the heating element found in thermal inkjet machines.  These work by applying a current which causes the crystal to change shape or size which then forces a droplet of ink through the nozzle and on to the paper.

Continuous Ink Jet
Continuous ink jet is one of the oldest ink jet technologies in use and is used commercially for making and coding of products and packages.  The technology works by using a high pressure pump which directs ink though a microscopic nozzle hence creating a continuous stream of ink droplets.  These droplets are then broken up at regular intervals by a piezoelectric crystal.

The ink droplets are subjected to an electrostatic field which results in a controlled electrostatic charge on each droplet and these are then separated by one or more uncharged droplets which minimize electrostatic repulsion between neighboring droplets.

The charged droplets are then directed to the media by electrostatic deflection plates, or are allowed to continue on undeflected to a collection gutter for reuse.