How do I clear a HP4301fdw jam (event code 13.10.04)?

[Philipsi]

My HP4301fdw printer has been working pretty well, but jammed today with event code 13.10.4. I was printing a single sheet using tray 1 (the multipurpose tray).

When the jam occurred, the paper was just starting to exit into the output bin. I was able to pull out some of the leading edge of the paper, but I think most of the sheet is still stuck inside the printer.

I don't see any way to get access to the part of the printer where the sheet is stuck. I can open the rear door, but don't see a way to get to the area near the slot where the paper exits to the output bin.

I pulled out tray 2, but don't see the stuck sheet or anything else of interest from the front of the printer.

Thanks for any tips you might have that can help me solve this problem.

[Philipsi]

I power cycled the printer a couple times, and now I see a different event code concerning the paper jam.  Either the code changed, or I made a mistake when I reported the event code earlier.  When I turn on the printer, I now see this on the control panel:

Paper Jam
Paper is jammed inside the printer. Open the rear door and clear any jammed paper.
Event code 13.10.14.

When I power cycle the printer, I hear some mechanical sounds that I suspect are caused by the mechanism that ejects the paper into the output bin.  That sound stops a short time after the printer finishes initializing.  After one of my power cycling experiments, I saw a little more paper peeking through the exit slot above the output bin, and I was able to extract the piece that was visible.  Pretty sure there's still more jammed paper that I can't see.  And the message concerning the jam does not go away.

I've opened the printer's rear door and looked around several times.  As far as I can tell, none of the jammed paper is visible, and there's no way for me to access the area below the paper exit slot from the rear of the printer.

Do I need to have the printer serviced by a pro?