Method for the self-control of devices for assessing the quality of printed products

摘要

This invention relates to a method for the self-control of devices for assessing the quality of printed products, in particular during the printing operation of offset printing machines. The aim of the invention consists in reducing the amount of waste paper and shortening repair times. The technical object therefore consists in providing a method with which failures of modules of the measuring device for assessing the quality of printed products can be reported directly after they have failed. The object is achieved in that, for the self-control of the measuring device consisting of a lighting arrangement, measuring-element arrangement and amplification modules, a) preferably white strips are measured, which are arranged transversely over the printing material, b) the measured values recorded by the individual measuring elements in the measuring-element row are compared with one another and with the measured values from the measurement of at least one of the preceding strips, and c) the deviations beyond a predetermined tolerance range are reported as a failure of the functioning of the measuring device.