Printer types and consumables: laser imaging process and maintenance kits, inkjet, thermal, impact, 3-D printers

Each printer technology has its own strengths, consumables and maintenance. Knowing them lets you recommend the right printer for a job and fix the right part when output goes wrong. The exam puts particular emphasis on the laser printing process, so learn its steps in order, and then learn what each other technology uses up and how you look after it. Laser printers use static electricity, toner and heat. The imaging process has seven steps. Processing: the printer receives the job and builds an image of the whole page in memory. Charging: a primary charge roller, or a corona wire on older printers, applies a uniform negative charge to the photosensitive imaging drum. Exposing: a laser writes the image onto the drum, neutralizing the charge wherever toner should go. Developing: charged toner is attracted to those exposed areas of the drum. Transferring: a transfer roller or belt gives the paper a charge so it pulls the toner off the drum, and a static eliminator then reduces the paper's charge so it does not cling to the drum. Fusing: the fuser assembly uses heat and pressure to melt the toner into the paper. Cleaning: a blade wipes leftover toner from the drum and the remaining charge is removed, ready for the next page.