Officejet Pro 8720 Placing unwanted vertical line on scans when using the Automatic Document Feeder

[Roccus]

I have a HP Officejet Pro 8720 that is three years old.  Recently, the scanner started to place a black line the length of the scan along one side, about the distance of a margin (but slightly slanted), when scanning using the document feeder.  It does not do this when using the flatbed.  The mark is on all images scanned and on prints of the images.  I found somewhere that cause could be related to the feeder mechanism, and that it should be cleaned.  I cleaned it as best I could, wherever I could reach when I opened up the feeder, to no avail.  I think it must have something to do with the document feeder as the flatbed works just fine.  I can clean up the mark, just like any of the rest of the scan, with Paperport software, but when it goes through lines of print, it is very tedious and unacceptable.  I have thought about replacing the document feeder, but cannot seem to be able to talk to anyone at HP because the printer is out of warranty.

I would greatly appreciate any help.  Thanks for your help.

I

[Valsimot · Accepted solution]

You need to open the top cover and clean smaller glass on the left side.

You can use a sheet with a line that will align with the dirt or smudge that is causing a line

[Roccus]

That worked!  Can't believe I did not clean that glass before...I cleaned the large one.  Thanks very much!