Printing – Processes – Position or alignment
Reexamination Certificate
2000-10-23
2004-12-07
Yan, Ren (Department: 2854)
Printing
Processes
Position or alignment
C101S383000, C101S415100
Reexamination Certificate
active
06827019
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to a rubber blanket with register cut-outs, and a method of aligning a rubber blanket, more particularly, formed with register cut-outs, relative to a clamping device having register pins, for clamping the rubber blanket onto a cylinder.
Such a method is described in the published German Patent Document DE 35 45 172 A1, corresponding to U.S. Pat. No. 4,707,902, wherein, initially, the ends of a rubber blanket formed with register cut-outs are inserted between clamping bars in a clamping device outside of a printing machine until the register cutouts come into contact with register pins belonging to the clamping devices. The clamping bars of the clamping devices are then connected by clamping screws, The clamping devices with the rubber blanket are then applied to a cylinder in the printing machine.
This method is unsuitable for printing or varnishing machines having clamping devices which are permanently arranged on the cylinder and which serve to fasten a printing plate to the cylinder. Because of the high flexural rigidity of printing plates, they are required to be rolled onto the cylinder, as described, for example, in the published German Patent Document DE 42 14 207 C1, for which purpose clamping devices applied permanently to the cylinder are used.
A rubber blanket corresponding to the rubber blanket generally described in the introduction hereto and in greater detail in the aforementioned published German Patent Document DE 35 45 172 A1 does indeed permit the alignment thereof in-register for cut-out in-line varnishing, but is unfavorable from several points of view because the register cut-outs are introduced directly into the soft blanket material.
On the one hand, the dimensional stability of the register cut-outs is very low. For example, distortion of the register cut-outs cannot be ruled out during frequently repeated fastening of the rubber blanket or because of swelling of the rubber. In addition, the risk exists that cracks will form at the register cut-outs as a result of careless handling of the rubber blanket.
On the other hand, the easily deformable register cut-outs require that the delicate ends of the blanket be aligned and firmly clamped very carefully outside the machine.
In addition, the published German Utility-Model Document DE 94 16 007 U1 describes a rubber blanket having a clamping bar which, in a construction as a flat profile, is vulcanized together with the rubber blanket only on the upper side of the blanket, so that the clamping bar ends flush with an edge of the rubber blanket. The design of the rubber blanket is unfavorable from various points of view.
On the one hand, the rubber blanket is unsuitable for cut-out in-line varnishing because this requires the top rubber layer of the rubber blanket to be cut out in locations corresponding to the varnishing cut-outs, as is extensively described in the aforementioned published German Patent Document DE 35 45 172 A1. Because the rubber blanket does not have any register cut-outs, cutting out the cut-outs in-register is possible only within the printing machine, which is very awkward to do.
On the other hand, the rubber blanket having the clamping bar formed as a flat profile assumes the presence of a clamping device having a maximum opening width, between a clamping pad and a clamping jaw, that is greater than the thickness of the blanket material together with the thickness of the clamping bar connected to the blanket material. Clamping devices which can be closed by rotating a slightly eccentric shaft do not always have such a large opening width, however.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an improved method of aligning a rubber blanket having register cut-outs, and to provide such a rubber blanket which is particularly well suited for performing the method.
With the foregoing and other objects in view, there is consequently provided, in accordance with one aspect of the invention, a method of aligning a rubber blanket formed with register cut-outs, relative to a clamping device having register pins, for clamping the rubber blanket onto a cylinder, which comprises bringing the register cut-outs formed in the rubber cylinder into contact with the register pins of the clamping device when the clamping device has been applied to the cylinder.
In accordance with another aspect of the invention, there is provided a rubber blanket having register cut-outs and being formed of blanket material, comprising a clamping bar of the rubber blanket, the cut-outs being formed in the clamping bar.
In accordance with a further feature of the invention, the clamping bar is disposed only on an underside of the blanket material.
In accordance with an added feature of the invention, the clamping bar projects beyond an edge of the blanket material.
In accordance with an additional feature of the invention, the edge is a leading edge of the blanket material.
In accordance with yet another feature of the invention, the register cut-outs are formed only in the clamping bar.
In accordance with yet a further feature of the invention, the rubber blanket includes a sealing substance provided in at least one corner angle between the blanket material and the clamping bar.
In accordance with yet an added feature of the invention, the rubber blanket includes a clamping device, only the clamping bar being grippable by the clamping device for fastening the rubber blanket to a cylinder.
In accordance with a third aspect of the invention, there is provided a rubber blanket comprising structures defining register cut-outs, the register cut-outs being arranged in the rubber blanket so as to correspond to register cut-outs formed in a printing plate.
In accordance with a fourth and a fifth aspect of the invention, there are provided a printing machine and a varnishing machine, respectively, having a rubber blanket with register cut-outs and being formed of blanket material, the rubber blanket comprising a clamping bar, and the cut-outs being formed in the clamping bar.
Thus, the method according to the invention calls for bringing the register cut-outs in contact with the register pins when the clamping device is applied or fitted to a cylinder.
This method is extremely well suited for printing or by varnishing machines having clamping devices permanently arranged on the cylinder, the clamping devices hating been originally provided only for fastening a printing plate, and being now also selectively used for fastening the rubber blanket. In the method according to the invention, the actions of aligning the register cut-outs in relation to the register pins, and firmly clamping the rubber blanket are performed within the printing or varnishing machine.
The rubber blanket according to the invention is distinguished by the fact that the register cut-outs are introduced into a clamping bar belonging to the rubber blanket.
In this rubber blanket, high dimensional stability of the register cut-outs is assured, which means that multiple in-register clamping of the rubber blanket is possible over a long service life. The clamping bar can be formed as a hard metal strip or plastic strip. For example, in a construction as an aluminum strip, the clamping bar is eminently practical. In order to align the rubber blanket, the register cut-outs introduced into the clamping bar can be brought into engagement with register pins of a clamping device applied or fitted to a cylinder.
In an embodiment which is advantageous with regard to the register cut-outs striking the register pin without tilting, the clamping bar or strip is arranged on the rear side of the blanket material of the rubber blanket, i.e., that side thereof which faces the cylinder and is formed, for example, of a fabric. When the clamping bar or strip is clamped into the clamping device, it therefore rests directly on a clamping pad belonging to the clamping device.
In an embodiment which is advantageous with regard to a clamping device having a small opening width,
Hieronymus Jens
Kropp Frank
Rothaug Jürgen
Schaum Frank
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Locher Ralph E.
Stemer Werner H.
Yan Ren
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