Off the glass as well as through the document feeder?
If ADF only (scan and copy) the issue is that this strip of glass on the left is dirty.
If Glass only it's the big piece of glass.
If on all copies but nothing else (scan or print), try Image Enhancement > Background suppression and verifyLighten/Darken is set to normal
If its on all output (Copies from adf and glass as well as print), the inside of the printer is dirty and likely needs a tech.
But first, at the printer go to Machine Status > Tools > Troubleshooting > Calibration > Print Calibration > Next and then just follow the directions