SUDDENLY THE ADF DOSEN'T WORK I GET AN ERROR MESSAGE THAT THERE IS A DOCUMENT IN ADF REMOVE AND PRESS OK
I place a stack of originals in the ADF and press Copy or Scan. There is a sound of a motor running, a pause, and then the motor running again. The paper is supposed to feed during this second phase but does not always feed. For me, it would fail to feed, ask me to clear the ADF, and press "OK" a random number of times and then suddenly it would work once or twice and then fail again.
I am a retired engineer and my feeling was that if could work properly even once, then it should work every time. The problem must be something intermittant relating to temperature, humidity, age, etc. It must be easily fixed.
The rear of the ADF has a silver-grey plastic piece which covers the feed motor and gears. You gain access by removing the one Phillips screw, opening the lid, and carefully prying the retaining lip at the right end of the silver-grey piece until it lifts up. The piece is then removed by sliding the retaining "leg" free at the right end of the piece.
Inside, you will see some white plastic gears. One gear is mounted on a floating idler arm. This gear controls feed and reject (I think). The feeder fails when this idler does not flip freely from one positon to the other. Carefully place a SMALL amount of very light (low viscosity) oil on the ider arm and verify that if easily moves back and forth.
Test the unit before replacing the silver gray cover piece.
That fixed it for me.
Email if you have questions.