Geometrical instruments – Area integrators – Electrical
Patent
1985-02-11
1986-08-12
Crowder, Clifford D.
Geometrical instruments
Area integrators
Electrical
101DIG12, B41B 100
Patent
active
046048111
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a fixture for printing plates to be mounted on impression cylinders of a Flexo-printing machine.
Flexo-printing is a high-pressure rotative process for e.g. the imprints on packing means, printed forms, prospectus or the like, where printing plates preferably composed of photo-polymers of rubber are glued onto the impression cylinders.
If one wants to print onto one and the same material in a simple manner letterings or e.g. pictures in different colors, then different plates are used which principally are applied on different impression cylinders in order to be able to carry out the printing work. However, that the coordination desired with respect to the printings relative to each other originating from the diverse plates can take effect, care must be taken that the plates will be arranged on the impression cylinders in an unmistakably coordinating position to each other. To this purpose one very often uses expensive paste-on machines, which enable the exact fitting coordination of one color to the other by means of mirror devices or any other optical apparatus. This kind of plate mounting is not only rather expensive but in addition presents considerable sources of error.
It is therefore the object of the present invention to make available a fixture for printing plates to be mounted on impression cylinders of a Flexo-printing machine, which makes it possible that different printing plates can be mounted in exact position on the impression cylinders of the Flexo-printing machine so that the finished printings will be perfect.
By the invention this object is realized in that the fixture comprises a rail or rib to be detachably mounted on the respective cylinder, which rib having projections or recesses intended for the accommodation of the printing plate. This fixture is mounted on the impression cylinder whenever a new cliche or, respectively a new printing plate shall be glued on the impression cylinder. Thereby always a clear orientation relative to the axis of the impression cylinder must take place. According to the invention this is guaranteed by the fixture. After this having been effected, the section getting in interaction with the rib is detached from said rib or rail in order to stick this area, too, onto the impression cylinder after the fixture itself has been removed. Accordingly the cliches, presenting a clear orientation with respect to each other in the machine, are applied to the other impression cylinders. Hereby it is guaranteed that the individual printing plates are arranged in exact fit to each other so that the finished printing work will not show any undesired overlappings caused by the individual plates. In order that the rib, which enables an extremely simple and exact fit of the arrangement of the printing plate on the respective impression cylinder, is running parallel to the longitudinal axis of the impression cylinder without any expensive adjusting measures, said rib or rail can be supported on the shaft of the cylinder and is at least partially enclosing said shaft. Hereby the rib is preferably of U-shaped configuration so that the angled-off legs extending at least partially along the faces of the impression cylinder, each having a recess adapted to the shaft. This can be e.g. the section of a hollow cylinder which is being mounted on the shaft. Of course, that section of the rib interacting with the shaft can also partially encircle the shaft from below in order to enable an even more safe arrangement of the fixture on the impression cylinder. According to an especially preferable embodiment of the invention those sections of the fixture extending along the faces of the cylinder are composed each of cheeks movable in the manner of scissors, having recesses facing each other of preferably V-shaped configuration, being interspersed by the pivot or, respectively the shaft of the cylinder, while at the same time an automatic centering is taking place. In addition, between the cheeks of each individual side section such a spring power is acting that
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patent: 3206859 (1965-09-01), Walsh
patent: 3550283 (1970-12-01), Bernardi et al.
patent: 4033259 (1977-07-01), Schuhmann
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