An inkjet printer is any printer that fires extremely small droplets of ink onto paper to create an image. If you've ever looked at a piece of paper that has come out of an ink jet printer, you know that:

• The dots are extremely small (between 10 and 30 dots per millimeter).
• The dots are positioned very precisely.
• In color printers, the dots can have multiple colors.

Inkjet printers are fairly inexpensive -- less expensive than laser printers, and much less expensive than color laser printers. Different types of inkjet printers form their droplets of ink in different ways. There are several technologies used by printer manufacturers, but by far the most popular technique is the bubble jet. In a bubble jet printer, tiny resistors create heat, and this heat vaporizes ink to create a bubble. The expansion that creates the bubble causes a droplet to form and eject from the print head. A typical bubble jet print head has 64 or 128 tiny nozzles, and all of them can fire a droplet simultaneously.