Apparatus for checking the in-register bearing of a printing plate on the plate cylinder of printing machines

An apparatus for checking the in-register bearing of a printing plate on a plate cylinder of a printing machine, especially a sheet-fed offset printing machine, the plate cylinder having a tension rail in a cylinder pit for receiving the printing plate edge assigned to the print start, said apparatus comprising:

• a set of measuring sensors mounted upon the tension rail providing a detectable electrical signal when the printing plate assumes an in-register orientation relative to the tension rail, the set of measuring sensors including a set of contact faces mounted upon the measuring sensors for tapping the electrical signals of the set of measuring sensors;
• and
• one or more sensing heads suspended on a frame and mounted movably relative to the plate cylinder, the one or more sensing heads being positioned in accordance with the contact faces such that the one or more sensing heads are placed against the contact faces when the plate cylinder is moved into an angular position providing for the loading of the printing plate into the tension rail.