User Check

1. Clean the corona wire or the power grid of the drum unit.
Slide the corona wire to the end and then back to the original place. Repeat this for at least 3 times

2. This problem will disappear after printing for a few pages.
3. Replace drum unit. <Video Link>

4. Replace toner unit. <Video Link>

5. There is dirt on the printer internal. wipe off the dirt on the paper path or roller.