Digital BW, The Print

The whole day I've been trying to solve a problem with the 3800 that
suddenly occured and wasn't there before (and drives me insane): when
I print, only the left quarter of the page (orientation Portrait) is
being printed. The rest of the paper remains blank, with a very sharp
border between the printed and the blank parts of the sheet.

Now the strange thing: this happens on Photo Rag. But when I print in
exactly the same way (changing NOTHING in the settings or whatever)
but insert a sheet of thin ordinary photocopy paper, it prints as it
should! I've tested it repeatedly and it is the same every time:
photocopy paper works fine, Photo Rag leaves the rightside 3/4 of the
paper blank.

Can someone please tell me what is happening here?

Thanks,

Igor