Check the following points to resolve the issue:

• Select Thick Paper mode in the printer driver or use thinner paper than you are currently using.
• (Not available for some models)
  Select the appropriate media type in the menu setting.
• Check the machine's environment. Conditions such as high humidity can cause hollow print.
  Refer to Product Safety Guide available on the Manuals section.
• 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.