Understanding how your printer works can help you understand its advantages and limitations, and help you diagnose and rectify print quality problems. Here is
a brief overview of inkjet technology which also offers some guidance on minimizing print quality problems.
How Inkjet printers work
An inkjet printer creates an image by placing droplets of ink onto the paper. These droplets are so tiny that they are smaller in diameter than a human hair!
The droplets are placed onto the page with extreme precision and the number of these droplets or 'dots' of ink determines the 'resolution and therefore the quality of the image.
The greater the number of dots per inch (dpi), the higher the resolution and the higher the quality, of the printed output.
For example, a resolution of 720 x 720 dpi could produce up to 518,400 dots of ink on a square inch of paper!
To make up the many different colours and shades in an image these dots of ink are combined together in a tiny array to
produce the full range of colour in an image. This system is known as 'half-tone printing'.
There are two main ways that inkjet technology is implemented - 'thermal' and 'piezo-electric'.
This technology, also known as 'bubble jet' is used in Canon and HP printers. It
works through ink being heated in a chamber in the 'print head' until a bubble is formed. As the bubble expands, ink is displaced and forced through a tiny nozzle
onto the paper. When the bubble bursts a vacuum is created, drawing more ink from the cartridge into the print head. A thermal inkjet print head can have as many as
600 of these nozzles, all capable of 'firing' at the same time.
This is Epson's patented technology and is used in their range of inkjet printers. It
uses a piezo-electric element, at the back of an ink reservoir, which vibrates when an electric current is passed through it. When the element flexes inward it forces a
droplet of ink out of the nozzle, when it flexes outward it draws replacement ink in from the reservoir.
The mechanism for delivering the ink to the paper is called the 'print-head' The print
-head is made up of many tiny nozzles, through which the ink is sprayed on to the paper. Depending on the make and model of the printer, the print-head can be part of
the ink cartridge or a separate unit which is either user replaceable (Canon and HP use both of these systems) or fixed into the printer (as used in Epson inkjets.)