Patent ID: 7854199
Filing Date: 2010-12-21
Classification: B41C,H04N

Abstract:
1. A method of imparting a print image on a printing plate, the method comprising: a) mounting the printing plate on an imaging drum in an orientation wherein a reference edge of the printing plate extends along the drum in a substantially axial direction; b) determining a location of at least one point on the reference edge, wherein the determining comprises: i) illuminating a region, the region comprising at least a part of the reference edge associated with each of the at least one point; ii) capturing at least one digital camera image of the region; and iii) locating the at least a part of the reference edge in the digital camera image; c) imparting the print image on the printing plate in alignment with at least the determined location of the at least one point; wherein the locating at least a part of the reference edge comprises locating a mechanical edge of the printing plate; wherein the illuminating is performed on the side of the printing plate that is in contact with the imaging drum; wherein the illuminating is by diffuse reflected light reflected from at least one diffusely reflective area on the imaging drum; wherein the illuminating is spatially interrupted by at least one non-reflective surface on the imaging drum; wherein the reference edge is positioned to extend over a slot in the imaging drum; the at least one non-reflective surface and the at least one diffusely reflective surface are on a radially recessed surface of the slot; and wherein the illuminating is spatially interrupted along an interrupting section of a part of the reference edge associated with the at least one point.