False paper jam HP Laser Jet M476dw

[John86CH]

The printer started showing "paper jam in the output bin" after every page that is printed. Opening the back door where you would normally find a paper jam and there is nothing there. After closing the door the paper jam message dissappears and the printer prints another page. Then it throws the jam message again, then you open and close the back door and it prints a page again. Help anyone? 

[Repairatrooper]

Check the flag in the output bin (those flaps hanging down that are listed by the paper as it exits)  and make sure it moves smoothly. Over time they can start to bind and hang open which triggers that error as there is a flag attached to that mechanism that triggers a sensor inside the printer so it knows when paper has exited or the output bin has filled to capacity.

[John86CH]

Thanks for the quick reply! I checked and the flaps seems to be freely moving. The error the printer gives is not the one with “output bin is full please remove paper before proceeding”, which I’d assume those flaps might trigger. The message in the screen says something like “Jam in the output bin, please open back door and remove jam”. What else could it be? 😞 Should I upload a video maybe to show what it does?

[John86CH]

I’ve also changed the paper pick up roller, but the jam error keeps coming back.. how can I check those flaps to see if they work as intended? It might be that the one to the right slightly comes down slower than the one on the left, and it seems it’s got maybe 1-2mm of ply at the bottom.

[John86CH]

Can you help me out with a part number for those flaps, or the sensor they actuate. Is there a way to clean them or do I have to replace them altogether?

[John86CH]

Can anyone help on this issue?

[Repairatrooper]

You should be able to find the service manual online, but it is unlikely that the sensor will be listed. The output sensor is just an optical unit that is tripped by a flag attached to the output bin flap. Try manually pressing down the flaps when a page exits to see if the sensor works or if there is a mechanical issue with the flaps.  The sensors HP uses are pretty standard, meaning you could scavenge one from another printer.