Colour registration marker scanning method for printing machine

摘要

The method involves using a sensor (1) which illuminates markers (5,6) with a light-source (2) focussed by a lens (3). A gathering lens (7) collects the reflected light flux for entry to a photosensitive receiver (8). A succession of signals of intensity dependent amplitude is generated by the receiver as the markers pass the lens. The signal amplitudes are equalised via a motor-driven filter-changing mechanism (11). Optimal filters (10,14) are interposed in the mechanism in response to a controller (17).