Please check the following points:

• Make sure that a torn piece of paper is not inside the printer covering the scanner window.
• Wipe the scanner window with a soft cloth. To see how to clean the scanner window, click here.
• The toner cartridge may be damaged. Put in a new toner cartridge. To see how to replace the toner cartridge, click here.
• The drum unit may be damaged. Put in a new drum unit. To see how to replace the drum unit, click here.