The quality of the output produced by computer printers or fax machines is greatly influenced by the type of printer ink used. While some type of printers and most fax machines use only black ink, there are the others that use coloured ink. Coloured printing requires two cartridges - one with black ink and one with the primary colours red, blue and green or separate cartridges for each of them. The ink cartridge is a reservoir of ink with a metal heating element. Once the printer receives a signal to print, a tiny current flows through this metal piece and warms the ink, which then exceeds out of the nozzle and is spread on the paper.

There are other factors like paper quality, type of ink cartridge, printer efficiency etc. Whatever be the printer ink colour, it is important to use compatible cartridges for guaranteed print quality. Inkjet printers (connected to computers and fax machines) use inkjet cartridges and laser printers use toners. On comparison laser printers are faster, efficient and expensive than inkjets. Most of the printer inks can be refilled on a DIY basis itself and those that cannot be refilled are remanufactured. This can also save a lot of money. HP, Canon, Epson, Lexmark are the prominent names offering unparalleled types of printers and premium printer inks.