Canon GPR-16 Black Toner

Is your printer feeding in the whole paper stack rather than just one piece at a time? Fan the paper before putting it in the tray to help separate the sheets. Also, store your paper in a cool, dry place as humidity can contribute to this problem.

Most printers have a paper-out detector. On most dot matrix printers it is a photo diode. If form-fed paper is not aligned correctly (usually on the left side) the diode won't see it.

Make sure to keep your printer up to date by downloading drivers and patches from the manufacturer's site. Most manufacturers provide driver updates for their units which include patches that add fonts or fix incompatibilities.