Patent ID: 6876716

Claim:
A method for identifying and counting printed products conveyed along a conveying path in a stream past a monitoring station in imbricated fashion with folded edges of each upstream printed product facing in a downstream direction and lying upon an upper surface of an adjacent downstream printed product, comprising: (a) triggering illumination of a light source at a rate relate to a linear speed of the printed products whereby folded edges of printed products conveyed through a region of an illuminating light beam from the light source which light beam forms an angle with the light path, to cause a shadow to form only on an upper surface of a downstream signature upon which the folded edge of the upstream printed product is placed; (b) substantially simultaneously with each triggering of the light source, capturing an image of a given region containing the shadow formed on each printed product passing through the monitoring station and intermediate opposite sides of said printed product; and (c) comparing the captured image with predetermined criteria to determine a presence of a leading edge to prevent disturbances from being erroneously identified as a leading edge.