Brother MFC-B7720DN
Troubleshooting. Image defect 3
Horizontal stripes
User Check
- This problem may disappear after printing multiple sheets of paper.
- Refer to <How to clean the drum unit> to remove the dirt from the exposure drum using a cotton applicator.
- Replace the drum unit with a new one.
- Replace the toner cartridge with a new one.
Step | Cause | Remedy |
---|---|---|
1 |
Dirty charge electrodes | Clean the electrodes of the drum unit and those of the machine. |
2 | Dirt on the exposure drum | Perform drum cleaning. |
3 | A ground wire or ground plate installation failure (Grounding is not performed correctly.) | Retighten the screws of each ground wire or ground plate. Repair the bend of the tray ground spring of the paper tray. |
4 | Scratch or dirt on the fuser unit | Replace the fuser unit. |
5 | High-voltage power supply PCB failure | Replace the high-voltage power supply PCB ASSY. |
White vertical streaks on image
User Check
- Check that there is no dust on the toner cartridge.
- Refer to <How to clean the drum unit> to remove the dirt from the exposure drum using a cotton applicator.
- Replace the drum unit with a new one.
- Replace the toner cartridge with a new one.
Step | Cause | Remedy |
---|---|---|
1 | Dirt on the exposure drum | Perform drum cleaning. |
2 | Laser unit failure | Replace the laser unit. |
White horizontal stripes on image
User Check
- This problem may disappear after printing multiple sheets of paper.
- Replace the drum unit with a new one.
- Replace the toner cartridge with a new one.
Step | Cause | Remedy |
---|---|---|
1 |
Dirty charge electrodes | Clean the electrodes of the drum unit and those of the machine. |
2 | Dirt on the exposure drum | Perform drum cleaning. |
3 | Scratch or dirt on the fuser unit | Replace the fuser unit. |
4 | High-voltage power supply PCB failure | Replace the high-voltage power supply PCB ASSY. |
Faint print
User Check
- Check that the machine is positioned on a level surface.
- Replace the drum unit with a new one.
- Replace the toner cartridge with a new one.
Step | Cause | Remedy |
---|---|---|
1 | Laser unit failure | Replace the laser unit. |
2 | Fuser unit failure | Replace the fuser unit. |
3 | Main PCB failure | Replace the main PCB ASSY. |