Wish I could help but we have the exact same problem. Throughout the Web there are lots of complaints about this but no answers.
HP, on their tech support phone number, will take a stab at verbal solving of this for $35 up front, REGARDLESS of whether they are able to provide a solution or not. Otherwise since it is out of warranty (only a year and a half old) they will offer a modest "discount" on a new replacement printer.
Nothing "office" nor "pro" about this printer, cheap junk!
I have just resolved a similar problem for a friend of mine who has this printer. The paper jam light is on but no paper jam - at leats that's what he thought. With these printers it is possible for a slither of paper to get caught between two of the gears/cogs that drive the paper feed mechanism.
The main symptom is that you hear (and can see inside) some juddering of the mechanism for about 10 seconds or so. The printer then realises that it can't roll the mechanism forwards and cuts out to prevent motor burn-out. The print jam light is then activated.
If you look into the back of the printer (remove the duplex cover), you should see a pair of white plastic gears to the left as you look in. In my case that's where there was a sliver of paper that had been sucked in, now jammed between the cogs but not visible. You need to reverse the mechanism by GENTLY rolling the gears with your thumbs so that the motion is outwards, i.e. so that the sliver is ejected from between them.
Of course I can't promise that this is the fault in your case, but it does catch out a lot of people. The printer is now as good as new and prints perfectly.
If it is flashing power button and paper refill as if you have a jam but you cannot see the paper - and it is stuttering after you press the paper button then in my case...
This was a tiny paper jam in the two 1cm left hand (looking at the back) cogs to the rear of the printer. You can use the large cog at the opposite end of the same cog shaft to slowly turn the shaft bag and forth until you spot the jam.
In my case it was a piece of paper little more than a pin head, but removing it fixed it.