feeder error

[robertkur]

I have a HP Pro MFP M521dn.  The feeder works but when all papers go through, the feeder acts as though there is more paper to feed in when there is none.  Then the printer gives an error  "Document Feeder Mispick".   I have to turn off machine to reset.  I don't see any paper jam.  I cleaned rollers etc.

[Repairatrooper · Accepted solution]

If you open the ADF top as you would to remove a jam, on the bottom there is a pad that separates sheets of paper. In that area is the flag that detects that paper is loaded in the adf. Your description suggests that the flag is sticking and so the printer believes that there is still paper in the tray and tries to feed it, and when the paper does not pass through to the next sensor the printer assumes there is a jam. It is not uncommon for the spring that returns the flag to lose strength. Disassembling the adf to access that flag is not a documented repair so you are pretty much on your own for the repair.

[robertkur]

I moved the flag back and forth.  It seemed to bounce back.  I shot some compressed air to be certain.  The problem still existed.  Then I manually pulled back the flag and that turned off the "paper loaded" message.  So I confirmed the problem was there.  Then I thought I might be able to attach a light rubber band some how.  In doing so, the flag appeared to pop up and I thought I did more damage.  But instead of damage the flag popped into a better position.  And now the flag and feeder seems to work properly.  Thank you for your info!