Friday, June 26, 2009

Color Laser Printer Developer Problems

Developing the image on a laser printer takes a laser, toner and the fuser.


Color laser printers use four toner colors (cyan, magenta, yellow and black) registered closely to produce the optical illusion of infinite color varieties. Using technology almost identical to xerographic copying, a laser printer uses a laser beam to expose a light-sensitive drum instead of the light wand passing under the original and reflected onto the drum in a copier. Paper is given a static charge, and the exposed laser-printer drum picks up toner and transfers it to the charged paper. A very hot fuser melts the plastic-based toner and seals it on the paper. Correcting poorly developed images on a laser printer usually involves the drum, laser, toner or fuser.


Drum


The image drum on a laser printer is part of the toner cartridge. On a color laser printer there are four drums, one for each color. If the drum is scratched or left exposed for long periods to direct sunlight it can lose its light sensitive properties. This results in poor toner transfer to the paper.


Fortunately, the drum is easily replaced when the toner cartridge is replaced. "Drilling and filling" a cartridge with replacement toner that has a damaged drum will not fix the problem. Only purchasing a new cartridge will replace the drum.


Laser


Although the laser beam scans the entire image width at several hundred or thousand times to the inch, the laser is fixed. A rotating mirror directs the laser across the drum and charges the light-sensitive surface.


If the printer has a damaged mirror mechanism, the image will appear skewed or completely blank. If the laser is damaged there will be no image. As with most electronic components, replacing the laser mechanism is the only repair option. As the laser is the most costly component on the color printer, you will need to decide whether to repair it or to replace the entire printer.








Toner


Laser printer toner of all colors is microscopic plastic pellets combined with iron filament. The iron makes the toner magnetic, and the plastic pellets convey the color. When toner cartridges run low, the image can be blurred, faded or appear streaked across the page. Replacing the cartridge will immediately repair the developed image problem.


Fuser








The fuser roller is the last component the paper passes through before exiting the color laser printer. The assembly is heated to several hundred degrees by a hot light inside the hollow roller. If the fuser goes cold the toner will not melt and fuse the page. It will exit the printer as dry powder. Repairing the fuser may only involve replacing the heating element. The roller itself is a simple mechanical assembly not easily subject to failure. An older printer, however, may see the fuser maintained at a high heat level for several years and the plastic parts damaged from the heat. Replacing the fuser is a simply unplug-and-plug procedure.

Tags: laser printer, cartridge will, color laser, color laser printer, drum laser