How to Fix Streaking and Lines on a Laser Color Printer

Power on the printer and open the toner cartridge cover. Lift the first toner cartridge out and set it aside.
Use the vacuum cleaner to remove toner residue from under the toner cartridge. This residue tends to accumulate under the cartridge, and it can cause streaks, lines and uneven coloration as the paper moves through the paper path.
Clean the area thoroughly with a soft cloth to remove any remaining paper dust and toner residue. Make sure the area is completely clean before moving on to the next area.
Rotate the toner cartridge carrier to the left and remove the next cartridge. The exact procedure for rotating the cartridge carrier varies from model to model, so consult your owner's manual. Many color printers use a button on the menu to advance each toner cartridge.
Clean the area under each remaining toner cartridge thoroughly, using first the vacuum cleaner and then the cloth. Continue cleaning the interior of the printer until no more toner residue is found.
Wipe each toner cartridge thoroughly before putting it back in the printer. Toner residue and paper dust tend to accumulate on top of the cartridge, and that residue will find its way on to the printouts. Replace any toner cartridges that appear to be leaking. A leaking toner cartridge can contaminate the entire paper path, and this problem is very difficult to resolve without a professional service technician.