User Check

1. The problem may disappear after printing a few pages.
2. Check whether fixed distance of the dust on the paper and measure it, 33.1 mm is toner issue and 75.4 mm is drum issue, confirm and judge which one need to be replace.

3. Replace drum unit. <Video Link>

4. Replace toner unit. <Video Link>

5. There is dirt on the printer internal. wipe off the dirt.