Laser cartridges are much more sophisticated than inkjet cartridges. They have many moving parts but they all have some things in common. Laser cartridges do not use ink, they use toner. Toner is a dry black powdery substance with the consistency of baking flour.

All laser cartridges consist of a drum, toner, corona wires and cleaning blades among other parts that include gears and other moving objects. The only similarity that they have to inkjet cartridges is the fact that you can refill them. You will not get as many refills from a laser cartridge because there are other parts that will eventually wear out that most people will not be able to replace without some technical skills. Expect about three refills on average from a laser cartridge.

Refilling a laser cartridge is not that difficult. First you need to gain access to the toner hopper. You can do this by either dis-assembling the cartridge or by using a tool to burn a hole into the cartridge right into the toner hopper. You re-fill the hopper with the proper amount of toner and re-assemble it or seal the fill hole. This is a rather simplistic explanation because there are so many different styles of laser cartridges and each one will have it's own procedure.

The way laser cartridges work is very ingenious. A photosensitive substrate is coated onto a cylinder or drum. The drum is charged evenly with electricity by the corona wire or corona strip. When the laser in the printer shines on the drum the electrical current at that particular area will be dissipated leaving a latent image or an invisible image made up entirely of electricity.

When the drum, with it's latent image, rotates to the toner area, it attracts toner to the drum only where the latent electrical image is. In other words the toner is attracted to the electricity that's left on the drum in the form of the latent image I just discussed. At this point there is a visible image on the drum made up of toner. When the drum rotates further the toner is transferred to the paper that is now passing through the printer. The toner is pulled off the drum by another corona strip or wire that has a higher voltage than the drum thus releasing the toner onto the paper. This corona is below the paper so the paper is passing between the corona and the drum. If you removed the paper from the printer at this point you would be able to see the image on the paper, but don't sneeze because you could blow the image right off the paper. After the image is transferred to the paper it must then pass through the fixing or fuser rollers where a combination of heat and pressure permanently bonds the toner onto the paper.

Sometimes toner gets on the coronas which can cause black or white streaks. Some laser cartridges come equipped with corona cleaners. Other parts that can go bad are the cleaning blade that cleans the drum or the drum itself can wear out. Replacing these parts goes way beyond this article.

Mostly, laser cartridges just run out of toner and the other parts are fine. The prices of some laser cartridges can go well over $100.00 so a few refills can really save you a bundle of money.