Printing – Print plate feeding or delivering
Patent
1995-04-07
1996-07-30
Bennett, Christopher A.
Printing
Print plate feeding or delivering
1014151, B41F 2100
Patent
active
055401511
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a process and a device for the removal of printing plates from plate cylinders of rotary printing presses.
DESCRIPTION OF THE PRIOR ART
A feed and removal device for a printing press is known from EP 02 14 549 B1, wherein, during the removal of the printing plates from the plate cylinder, the printing plates are held by means of guide rollers, which can be placed against the circumference of the plate cylinder, and by associated actuation devices. This is disadvantageous in that these adjustable plate pressure rollers and their actuating devices not only make access to the plate cylinder more difficult, but also require an additional outlay in technical devices. Further than that, a large portion of the circumference of the plate cylinder is occupied by the above mentioned devices, so that only a limited number of cylinders, for example ink application rollers, can be present at the plate cylinder, otherwise the plate cylinder must have larger dimensions. In connection with above mentioned EP 02 14 549 B1 it is furthermore disadvantageous that a driven guide roller is employed during the plate feeding process and is in contact with the sensitive side of the printing plate. This can lead to damage of this sensitive side, particularly if the feed speed of the printing plate is adjustable in the way this is handled in accordance with EP 02 14 549 B1 by accelerating and subsequent slowing down of the plate feed.
During the plate retraction or plate removal process it is furthermore disadvantageous that here too, a driving guide roller is employed which is in contact with the sensitive side of the printing plate, so that damage to it cannot be counted out, which is an obstacle to the reuse of the printing plate.
SUMMARY OF THE INVENTION
It is the object of the invention to produce a process for the removal of printing plates from a plate cylinder of a rotary printing press and a device for executing the process.
The following advantages in particular are achieved by means of the invention.
Driven conveying members for the printing plates, such as drive rollers, do not come into contact with the ink-carrying sensitive side of the printing plate, so that the printing plate is not damaged during changing and therefore nothing stands in the way of reusing it. Because of the simultaneous use of the ink application rollers as an auxiliary drive or conveyance for the printing plates to be removed, the ink application rollers have a multiple function. Further than that it is possible to place a plurality of ink application rollers against the plate cylinder. Because of the arrangement of air conduits and by blowing on the sensitive side of the printing plate in the storage compartment it is assured that this side does not come into contact with the storage compartment and thus a gentle removal of the printing plates takes place.
BRIEF DESCRIPTION OF THE DRAWINGS
The associated drawings show in:
FIGS. 1 to 4, respectively schematic side views of a feed and removal device for printing plates in various positions of the plate cylinder;
FIG. 5, a partial, enlarged representation of a portion of FIG. 3;
FIG. 6, a representation of the plate front edge of a printing plate in the plate alignment unit;
FIG. 7, a control device and a control computer;
FIG. 8, a flow chart for the removal of a printing plate from the plate cylinder;
FIG. 9, a flow chart for feeding a printing plate to the plate cylinder; and,
FIG. 10, a section taken along line X--X in accordance with FIG. 6 and with an enlarged representation of a detail of the apparatus in accordance with FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The structure of a device in accordance with the invention in the different plate cylinder positions is shown in schematic representations in FIGS. 1 to 4. A rotary printing press has several printing units 1, for example four printing units, each of which contains, among other things, a plate cylinder 2, a rubber blanket 3 and a counterpressure cylinder 4. Furthermore
REFERENCES:
patent: 5111744 (1992-05-01), Wieland
patent: 5127328 (1992-07-01), Wieland
Ruckmann Wolfgang G.
Wieland Erich G.
Bennett Christopher A.
Koenig & Bauer Aktiengesellschaft
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