Please check the following points:

• Is the toner cartridge properly installed in the printer?
  Make sure that the toner cartridge is installed properly.
  To see how to replace the toner cartridge, click here.

• The transfer roll cartridge, or fuser unit might be old or damaged. We recommend you replace them as necessary. To see how to replace the Fuser Unit & Transfer roll Cartridge, click here.

• Dirt might be on the laser window. Clean the laser window.