Apparatus for detecting printing plates and a printing plate monitoring system for a printing press

Abstract

Apparatus for detecting the presence of a partially loaded printing plate in individual printing plate mounting positions on a plate cylinder (2) of a printing press is disclosed. The system includes a discrete vacuum circuit associated with each individual printing plate mounting position. Each vacuum circuit includes suction elements (6) positionably spaced from the surface (2a) of a plate cylinder (2) so that, when a leading edge (7a) of a printing plate (7) has been received in a lock-up slot (10a) in a plate cylinder which is rotated to partially wrap said printing plate around said plate cylinder, a trailing edge (7b) portion of a printing plate is deflected away from the surface of the plate cylinder, due to its resilience, against the suction elements. It is thereby possible to generate a negative pressure in the vacuum circuit closed by said trailing edge portion of the printing plate against the suction elements. The existence of a negative pressure is used to indicate the presence' or absence of a partially loaded printing plate in each of the printing plate mounting positions.

Description

technical field [0001] The invention relates to a device for detecting printing plates. More specifically, it relates to an apparatus for detecting the presence of a partially loaded printing plate in an individual printing plate position on a plate cylinder of a printing press during a printing plate loading cycle, the invention also relates to a A printing press of a plate cylinder of the apparatus described above, and a method of detecting the presence of a partially loaded printing plate in an individual plate mounting position. The invention also provides a printing plate monitoring system and a method for monitoring a printing plate on a printing plate cylinder of a printing press. The plate monitoring system provides the operator of the printing press with information about the loading status at each plate position. Background technique [0002] A web offset printing press includes a plurality of printing units, each designed to print content onto a continuous web a...

AI Technical Summary

Problems solved by technology

However, the plate inspection system disclosed in that application can only check for the presence of plates that have been fully loaded onto the plate cylinder, i.e. the leading and trailing edges of the plates have been received and clamped in their locking grooves middle

[0011] Furthermore, known plate inspection systems also rely on a plurality of ventilation channels formed in their own plate cylinder which are blocked by the presence of the plate so that when a When a set of suction cups contacts the surface of a printing plate in the plate position on the plate cylinder, the vacuum circuit associated with the set of suction cups is closed, causing a negative pressure in the circuit

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