Please check the following points:

• Make sure that the toner cartridges are installed properly.
   
• Make sure that the drum unit is installed properly.
   
• Make sure that the belt unit is installed properly.
   
• Make sure that the waste toner box is installed properly.
   
• Perform the calibration.
  To see how to perform the calibration, click here.
   
• Adjust the colour by using the custom setting in the driver and by using the control panel. Colours the printer can print and colours you see on a monitor are different. The printer may not be able to reproduce the colours on your monitor.
   
• Make sure that you use paper that meets the printer's specifications.
  To see what kind of paper you can use, click here.
   
• Put in a new drum unit.
  To see how to replace a toner drum unit, click here.
   
• Put in a new belt unit.
  To see how to replace a belt unit, click here.