LaserJet MFP M527 Not Scanning from Document Feeder

[waterd]

Hello,

When attempting to scan/copy from the document feeder by loading paper into it, the printer will instead scan from the glass rather than the document feeder. The glass scanning area is clean and has no paper on it. I feel that there may be an issue with the document feeder sensor, where it is not detecting that paper has been loaded to it. Or, mechanical failure of the lifting mechanism to feed to document feeder. What can we do from here? 

[Repairatrooper · Accepted solution]

Do you get the beep when you load the paper? If not then either the sensor has broken or is dirty. If you open the adf cover as you would to access a jam, you will see a plastic fin in the middle of section where the paper rests once you have inserted it. This is the flag that detects paper presence in the adf. When there is no paper, the flag blocks the optical sensor underneath. When you insert paper, the flag unblocks the sensor. If there is excessive dust it can cause the sensor to always read that there is no paper inserted. Shot of canned air down around the flag might help. Flag should tip back and forth with no resistance.

[waterd]

Thank you so much Repairtrooper! I had a feeling it was related to the sensor, but didn't know what mechanism it used to detect paper. This fixed it perfectly!