Patent ID: 7989788
Filing Date: 2011-08-02
Classification: B41F,G03F,H04N

Abstract:
1. A method for determining a position of a mechanical edge of a reference edge of a sheet of recording media relative to a first edge of a drum slot in a cylindrical surface of an imaging drum, the method comprising: a) mounting the sheet of recording media on the imaging drum in an orientation wherein the reference edge extends along the cylindrical surface of the imaging drum in a substantially axial direction and wherein the reference edge extends over the first edge of the drum slot; b) establishing at least one acute reflective apex in the slot; c) capturing at least one digital camera image of the reference edge and the at least one acute reflective apex; d) determining from the at least one digital camera image a location of at least one point on the mechanical edge; and wherein the establishing comprises illuminating a reflective layer in the slot using an illumination source and casting a shadow of a second edge of the drum slot on the reflective layer, at least part of the perimeter of the shadow being non-parallel with the first edge of the drum slot.