Week Ten

Components of a Laser Printer

• Toner Cartridge - Supplies the toner that creates the image on the page. 
• Photosensitive Drum - An aluminum cylinder coated with particles of photosensitive compounds.
• Erase Lamp - Exposes the entire service of the photosensitive drum to light, making the photosensitive coating conductive.
• Primary Corona/Charge Roller - Charged with an extremely high voltage, causing an electric field enabling voltage to pass to the drum and charge the photosensitive particles on the service. 
• Laser - The writing mechanism of the printer. Any particle on the drum struck by the laser becomes conductive and its charge is drained away in o the grounded core of the drum.
• Toner - A fine powder made up of plastic particles bonded to iron particles. Particles of toner are attracted to the areas of the photosensitive drum that have been hit b the laser.
• Transfer Corona/Transfer Roller - To transfer the image from the photosensitive drum to the paper, the paper must be given a charge that will attract the toner particles off of the drum and on to the paper. Newer printers use a transfer roller that draws the toner onto the paper.
• Fuser Assembly - Two rollers, a pressure roller and a heated roller, are used to fuse the toner to the paper. The pressure roller presses against the bottom of a page, while the heated roller presses on the top to melt the toner into the paper.
• Power Supplies - All laser printers have at least two power supplies. One provides power to the motors that move the paper, the laser, and the transfer corona/roller. The high voltage supply provides power only to the primary corona/roller.
• Turning Gears - Used to pick up the paper, turn the photosensitive roller, evenly distribute the toner, and activate the fuser assembly. In most laser printers gear systems are packed together in units called gear packs. Most laser printers have two or three gear packs. 
• System Board - On each electronic board is a processor, the printer's ROM, and the RAM used to store the image before it is printed. Many printers divide these components among two or three boards.
• Ozone Filter - Special filter to catch ozone. Needs to be vacuumed or replaced periodically.
• Sensors and Switches - Spread throughout the printer. The sensors detect issues such as paper jams or low toner levels.

Source:

Meyers, M. (2012). All-in-one CompTIA A certification exam guide: (exams 220-801 & 220-802). New York: McGraw-Hill.