A method of an embodiment of the invention is disclosed that advances media sheets
through an image-forming device such that each successive pair of media sheets
are advanced at least substantially adjacent to one another. The method transmissively
optically senses a leading edge of each of the media sheets and a lagging edge
of each of the media sheets. The method detects occurrence of an out-of-media sheets
situation where a length of time after the lagging edge of one of the media sheets
has been optically sensed exceeds a threshold length of time.