HP Officejet 6500 - Manual (Page 166)

To clean the glass strip inside the automatic document feeder
1. Turn off the HP all-in-one, and unplug the power cord.
NOTE: Depending how long the HP all-in-one is unplugged, the date and time
might be erased. You might need to reset the date and time later, when you plug
the power cord back in.
2. Raise the lid, as if you were loading an original on the glass.
3. Lift the cover of the automatic document feeder.
Chapter 9
162 Maintain and troubleshoot