Paper feed rollers have stopped feeding paper?

"Same problem, fixed for now using 5 minute epoxy... Slid the gear to the side... Dabbed epoxy on the axis, slid it back in, let it dry overnight. Taking the printer appart is a pain though... All that for a 1 cent plastic part that is an engineering defect !

Mise à jour (15/01/2016)

Well had to redo it tonight after printing out a good number of pages...

Here are 2 pictures to illustrate how to do it without taking it apart but by using a mirror to see the gear.

Global view to see where to put the mirror and where the gear is.

Zoom in on the mirror and you can see the gear and epoxy as it dries. You can use the gears to the left to rotate the axis and dab it homogeneously.

With the mirror it was real quick... Now lets see if it worked again...

Regards"

Das Problem liegt daran, dass ein kleines Zahnrad auf der Zahnstange auf die Seite gerückt ist. Wie benjaminreveille geschrieben hat, kann man das Zahnrad mit einem Spiegel lokalisieren und wieder an die richtige Stelle verschieben. Wer keinen Kosmetikspiegel zur Verfügung hat, kann sich auch mit einer CD helfen.

"Scenario 1: the pick-up drums do not roll, you hear a grinding noise

You most likely hear a grinding noise of plastic cogwheels slipping when the printer tries to feed a sheet of paper.

It looks like there is too much play in the paper pick-up unit (at the rightmost end inside the printer) on which both pick-up drums are mounted on a single arm. When not printing, these drums are lifted. When printing, they are dropped to the top of the paper stack and will engage to separate the topmost sheet off the stack.

When lifted, you will be able to rotate these drums in one direction. When the drums touch the paper, they simply don't rotate.

I suppose that because of excess play (programmed obsolescence?) eventually the cogwheels that drive the drums will slip. Sadly this unit is hard to reach.

Probably the entire printer must be torn down, and I don't expect you will be able to easily fix the excess play on the paper pick-up mechanism that drive the rubber rolls when pressed on the stack of paper.

Scenario 2: the pick-up drums do roll, but they slip on the paper

There are image and video instructions available from HP. Here's a written summary based on my experience:

If you see the paper pick-up drums slip on the paper, then you may have better luck. Unplug the printer's power cord, detach the duplex unit at the back (push to the left and pull back to disengage the unit from the printer). You can now see 4 rubber drums on an axis. Clean these with a Q-tip moistened (not soaked) in clean water, and move from left to right. Rotate the axis upward (only possible way) to clean the next section of the 4 rubber drums. Now take another moist Q-tip and swipe the rubber-covered grooved paper pick-up drums clean in a similar fashion. This is tricky since you need to reach into the printer from the back (left). Let the water evaporate and reassemble the duplex unit. Print a test page (e.g., a blank Word document to avoid wasting ink). If the rubber pick-up drums still slip, repeat the cleansing operation."

"Cut a hole on the bottom of the printer (with Dremel tool). Drill a whole through paper feeder driving slipping gear and its shaft (I used Dremel and 0.70 mm drill). Then put a pin in the whole (I used a solid copper wire). That is it.

P.S.Before drilling the gear move it ( on the shaft) toward the center line of a printer. So.the gear is fully engaged with the opposite gear, but potion of the gear is free of engagement . That is where you drill the gear and shaft. So , the pin/wire wont impede with the gears rotation.

Ooops, totally forgot.Before you flip your printer to cut a whole REMOVE ink cartridges!!!!!!

Update (11/10/2017)"

"I had the same issue with our years-old 7520. The gear was pretty tight on the axle, and would turn most of the time, but not all... Like when it applied pressure against paper. I flipped the printer over and used a mirror to inspect.. eventually I found that the gear had a crack between two teeth.

I didn't want to take it apart and struggled to get epoxy in the right place so I ended up cutting a hole in the paper tray. Figured I'd upload the images to help someone else know where to cut if needed.

It's about 3/4” by 1 3/4”, cut with a Swiss army knife.. nothing special. Got me right where I needed to be."