epson dx8400, stops printing?

have an epson dx8400, had a paper jam which i cleared, but now it only prints half the page then stops . screen says to turn printer off then on again, but this does not cure the problem, as when i switch back on, it rejects the current page, then, when i try to print again the same thing happens, it prints half the page, and then stops. there are no scraps of the jammed page left in the printer, i got it all out. what's causing this ? and how do i sort it ?