Check the following points to resolve the issue:

1. Make sure that the media type setting in the printer driver matches the type of paper you are using.
2. Check the machine's environment. Conditions such as high humidity can cause hollow print.
3. If the problem is not solved after printing a few pages, foreign material, such as glue from a label, may be stuck on the drum surface.
4. Install a new drum unit. Click here to see the details of how to replace the drum unit.