Please check the following points:

• Check the printer's environment. Conditions such as humidity, high temperatures, and so on, may cause this print fault.
   
• If the whole page is too light, "Toner Save Mode" may be on. Turn off "Toner Save Mode" in the printer Properties tab of the driver. To see how to turn off the Toner Save Mode, click here.
   
• Put in a new toner cartridge. 
  To see how to replace the toner cartridge, click here.
   
• Put in a new drum unit.
  To see how to replace the drum unit, click here.
   
• You may clear the problem by wiping the scanner window with a soft cloth.
  To see how to clean the inside of the printer, click here.