The present invention relates to a method for checking printing form surfaces engraved by means of an electron beam which creates cup-like depressions in the printing form surfaces.
Methods for producing printing forms by means of an electron beam are already known wherein the material of the surface of the printing form is removed by means of the electron beam, for example German Pat. No. 55 965, incorporated herein by reference, in which the principle of electron beam engraving is described. It is desirable, however, to check the result of the engraving, i.e. to check the cups engraved in the printing form surface and to make them visible. A stereo microscope is built into the electronic beam generator for this purpose given devices for material processing, for example German Pat. No. 10 99 659, incorporated herein by reference.
A separate monitoring beam path that is directed at a radiation receiver 19 is provided in German Pat. No. 12 99 498, incorporated herein by reference. A photo-electric transducer is provided as the radiation receiver, this being followed by a display means from which a direct conclusion concerning the focus status of the electron beam may be drawn. This signal can then be employed for the intensity control of the processing beam.
These devices are unsuitable for a direct, optical check of the engraved cup.