We're having an issue with vertical lines appearing on emails and scans coming from the topside ADF. I've cleaned the appropriate scanning glass (the thin strip glass beside the main scanning bed), ran some heavy duty paper through to try to clear up any potential debris, and still the scans come through with lines.

The lines vary in color in emailed scans, and I'm wondering if there isn't something going on inside the glass itself, or perhaps something in the ADF machinery causing the lines. Have any of you come across lines that persisted through regular glass cleaning? If so, were you able to correct the issue, and how?

Thanks for any tips, guys.