MEASURING RELIEF IMAGED PRINTING PLATES

摘要

The present invention provides a method and an apparatus for measuring relief imaged printing plates. The method comprises providing a source of illumination and directing the light therefrom into an optical element whereat the light is subjected to total internal reflection by at least one face of the optical element which face is exposed to enable it to be brought substantially into contact with a relief imaged printing plate, whereby when a relief imaged printing plate is brought into contact with the face or faces of the optical element, the raised parts of the relief imaged printing plate that are closest into contact with the face(s) of the optical element locally disrupt or "frustrate" the total internal reflection of the light, a detector being provided to detect the reflected or back scattered light to obtain an electronic image of the relief image on the relief imaged plate, the electronic image then being fed to an electronic circuit for analysis to determine the ratio of imaged to non-imaged surface area.