![Print Quality Problem - Black toner marks across the page](/g/b/img/faqend/faq00000219_021/ph/en/21818/BlackTonerMarks_HR1.jpg)
Please check the following points to solve the problem:
- If you use label sheets for laser printers, the glue from the sheets may sometimes stick to the OPC drum surface. Clean the drum unit.
Please refer to the instructions, "Clean the drum unit."
- Make sure that you use paper that meets our specifications.
Please refer to FAQs, "What kind of paper can I use?" and "What is the recommended paper?"
- Do not use paper that has clips or staples because they will scratch the surface of the drum.
- If the unpacked drum unit is in direct sunlight or room light, the unit may be damaged.
- The toner cartridge may be damaged. Put in a new toner cartridge.
Please refer to the instructions, "REPLACE TONER".
- The drum unit may be damaged. Put in a new drum unit.
Please refer to the instructions, "REPLACE DRUM".