I gather there are two steps, at least, to the printing process. The first applies the ink, the second fuses it to paper.
If that's correct, it still may be a paper jam issue. Because if the jamming comes before the fusing, of course the ink is not properly attached to the paper.
I got a nice small laser printer for ten dollars at a school rummage sale, and when I tried it, it jammed. It turned out to be something as simple as scotch tape stuck inside the paper path. Once that was cleared out, it worked fine. But it was really slow, so I didn't stick with it. Too bad because it was a real postscript printer, and nice and small.
Michael