What are you supposed to do when your printer says "Jam Tray 1" and there's no paper jam to be found?
We have this Brother HL-3170CDW printer:
(It's a great printer: fast, prints duplex and reasonably priced. Although, a bit big and heavy.)
And it stopped working due to a paper jam error and despite not finding any paper jammed in it, it still claimed it had paper jam. The manual was unhelpful in solving the problem. Web searches didn't provide a solution. I emailed Brother support, and they gave me the solution.
Here I reproduce the Brother support email almost verbatim for other people who had the same problem can find this page for a solution.
Thank you for contacting us about your HL-3170CDW. We understand that the Jam Tray 1 message is not clearing. We understand that you have thoroughly checked the machine, and we thank you for completing those steps.
We do have just a couple more steps for us to try before we are able to into warranty options for the unit. To complete these steps, please open the top cover of the machine. Remove the drums and toners, as well as the belt unit from underneath this area. Please also remove the paper tray from the machine as well before completing the steps listed below.
Obtain 5 sheets of 20lb OR 4 sheets of 24lb letter size paper (8.5" by 11"). Stack the sheets of paper together. Fold the entire stack of paper in half, top to bottom. The size of the paper stack now will be 8.5" by 5.5" (folded top to bottom).Look in the area where the paper tray was removed from. In the upper portion of the machine in the paper tray opening area, locate 3 gray rollers. There is one wide roller and two narrow rollers behind the wide roller.
Take the folded paper stack and place the folded edge of the paper stack against the wide gray roller near the front. Placing the paper in this position will align it with the paper slot that guides the paper into the drum/toner area manually feeding the paper through the paper path.
Holding the paper stack with both hands and while applying firm pressure, push the folded paper stack into the paper slot until. Once the paper stack has been pushed half way or far enough into the paper slot, it will enter the inside of the machine (toner/drum area).
Pull the folded stack of paper out of the machine.
If any small scrap pieces of paper come out, remove them and then reinstall the belt unit back into the machine. Reinstall the drums and toners. Reinstall the paper tray.
If the Jam Tray 1 message still shows after completing these steps, we will need to go into warranty options for you unit.
I followed the instructions and no pieces of paper came out. But, when put back together and restarted, there no longer was a paper jam error.
And after I printed the first page afterwards, the jam was confirmed. It coughed up this piece of paper with the page I had printed: