If you are having a 'Paper Jam' issue on a brand new HP OfficeJet 7000, then learn from our experiences and do not buy cheap paper!
One of our customers reported a print problem with a brand new HP LaserJet 7000 we supplied the day before. The print server was reporting a 'Paper Jam' status and we were able to clear this by a restart of the print spooler.
We then carried out a number of print tests starting with the A3 paper that was in the printer. No amount of server test pages would work. I even tried using the embedded control panel which also failed to give any results.
For some reason I decided to try A4 paper and the results improved. Every test page I printed worked perfectly well. Swapping back to the A3 and the problems came back. We swapped to some thicker A3 photo quality paper in the printer - the prints worked.
The moral of this story was that the paper that the client was using was too thin for the printer pickup rollers to handle. I would guess it was less than 80gsm. The HP web site suggests that 60 - 105 gsm should be okay... but we say go for at least 100gsm.