Laser printers are likely the best printers that you regularly use.  They are also complicated and often misunderstood by end users when problems begin to arise.  Follow these simple tips and you will eliminate many problems and reduce frustration levels...

1.  It's probably the toner cartridge.  If you are having problems with print quality, replace the toner cartridge.  Many times, this is the cause of streaks, light spots, ghosting, and other problems.

 
2.  Don't blow canned air inside a dirty printer!  Loose toner can find its way onto laser lenses causing worse problems.

 
3.  Use quality supplies.  This includes Maintenance Kits, Paper, and Toner Cartridges.  Third party products and "refurbs" often fail faster than manufacturers original parts.

 
4.  Be careful printing on anything other than normal paper.  Envelopes, labels, or transparencies can instantly ruin a fuser by melting and contaminating the fuser roller.

 
5.  Check your connections.  A loose printer cable can present confusing symptoms.  Some printers (like HPs) will display a printer error, leading you to believe the problem is in the printer!

-And ALWAYS unplug a laser printer while working with it.  There are high voltage wires and very hot surfaces inside that can cause injury.