Check the following points to resolve the issue:

• If you use label sheets for laser printers, the glue from the sheets may sometimes stick to the drum surface. Clean the drum unit.
  > Click here to see how to clean the drum unit.
• If you used paper that has clips or staples, the drum unit may be damaged.
• If the unpacked drum unit is in direct sunlight (or room light for long periods of time), the unit may be damaged.
• Clean the drum unit.
  > Click here to see how to clean the drum unit.
• The toner cartridge may be damaged. Replace the toner cartridge with a new toner cartridge.
  > Click here to see how to replace the toner cartridge.
• The drum unit may be damaged. Replace the drum unit with a new drum unit.
  > Click here to see how to replace the drum unit.