Plate cylinder arrangement for a printing press

DETAILED DESCRIPTION It is an object of the present invention to provide a printing press plate cylinder which has the above-mentioned features and with which it is possible by structurally simple means to bring the respective color back into registration very quickly, possibly even with the press running, thus avoiding the described drawbacks.
The above and other objects are accomplished in the context of a plate cylinder for a printing press as first described above, where adjustment means are provided between the two tensioning rails for displacing the two tensioning rails against spring forces in the circumferential direction of the plate cylinder toward the exterior of the trough, with the forward tensioning rail being separately adjustable at both its ends while the rear tensioning rail is adjustable in a direction parallel to itself.
These measures make it possible, once an undue color deviation has been noted for the respective color run, and thus the printing plate is already clamped onto the cylinder, to initially release the tension on the rear tensioning rail.
This results in a displacement of the rear tensioning rail parallel to itself or essentially parallel to itself in the direction of the rear trough wall.
Thus, there is enough room for the forward tensioning rail to be subsequently canted to such a degree that the respective faulty alignment is compensated or at least compensated, as much as possible.
Then, the stops for the rear tensioning rail are moved back again so that the springs of the rear tensioning rail are able to tension it to the desired degree.
If these measures are not yet sufficient to completely correct the error, the measures are repeated once more in the described sequence.
For a manual displacement, it will generally be enough to perform a single series of these measures, while for a motor driven adjustment by way of sensors, which can then also be performed with the machine running, the described process steps are generally smaller and must therefore be performed several times in succession until the error has completely disappeared