A sensor system for detecting skew in print media along the feed path of a hardcopy device is disclosed. In one embodiment of the invention the system is arranged to generate a first image of a portion of print media at a first position along the feed path and to generate a second image of the portion of print media at a second position along the feed path, the system is arranged to compare the first and second images and thereby detect a change in the angle of skew of the media between the first and second positions.