Printing – Printing members – Blanks and processes
Reexamination Certificate
2001-07-30
2004-04-06
Meier, Stephen D. (Department: 2853)
Printing
Printing members
Blanks and processes
C101S465000
Reexamination Certificate
active
06715419
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method and a device for producing a printing image carrier on prefabricated carrier material in a printing machine.
The published German Patent Document DE 195 3 6 884 C1 describes a device for wrapping a flexible printing image carrier around a printing form cylinder. Provided in the interior of the printing form cylinder is a first winding spool or coil for unwinding a printing image carrier which is drawable onto the casing or jacket surface of the printing form cylinder, and a second winding coil or spool for winding the printing image carrier drawn onto the jacket surface. Formed in the circumferential surface of the printing form cylinder is a single opening to an indentation in the interior of the printing form cylinder, wherein the first and the second winding spools or coils are arranged together. From this opening, the printing image carrier can be wound from the first winding coil or spool onto the jacket surface, and from the jacket surface onto the second winding coil or spool.
This heretofore known device of the German patent document is further characterized by the feature of a bearing part which is disposed so as to be removable from the interior of the printing form cylinder in the state wherein it is installed in the printing machine.
The European Patent Document EP 0 770 494 A2 is concerned with a method for making a printing form, the method being performed within a printing machine. An image-wise exposure of an image element takes place on a hydrophilic surface of a printing plate of an image-carrying layer. Contained in the image-carrying layer are hydrophilic thermoplastic polymer particles, which are dispersed in a hydrophobic binder. Furthermore, a mixture is provided which converts light into heat, the image element created in this way being applied to an impression cylinder which is provided in a rotary printing machine, and is inked via a dampening solution and/or ink during the rotation of the impression cylinder.
The published European Patent Document EP 0 802 457 A1 describes a device for producing and producing an image on a printing plate. A print carrier is disclosed, and equipment is provided for applying a uniform coating; devices are also provided for exposing the uniform coating in accordance with an image pattern, and further devices are provided for developing the uniform coating so that an image remains on the print carrier.
The printing image includes ink-accepting or ink-friendly areas on an ink-repellent background, or ink-repellent areas on an ink-accepting or ink-friendly background. The print carrier includes a cylinder, on the circumferential surface of which an element in sheet or plate form is mounted, the surface of the element being either an ink-accepting or ink-repellent type of surface. The aforementioned published European Patent Document EP 0 802 457 A1 also discloses a method for making a print carrier, the device described hereinabove being used therefor, as well as a coating fluid to be used in the device.
U.S. Pat. No. 5,713,287 discloses an imaging or image-generating method wherein the surface of a single-layer coating is modified.
In a direct imaging system with a gapless cylinder, the latter is provided in the printing machine with a radiation-curable polymer. After curing the polymer, the surface of the polymer is modified by selective irradiation with a laser light source, so that the affinity to the printing ink is changed. The cylinder thus formed is installed, in the place of a plate cylinder, in an offset printing machine, which operates either conventionally or without water. Because only the surface of the cylinder is selectively modified by the laser, the coating thickness and uniformity are of little concern. After the printing operation, the cylinder is cleaned, for which a cleaning station similar to a blanket washer in printing machines is installed. The cleaning operation does not have to be complete, because the surface of the cylinder of the printing unit is never entirely exposed to the printing ink. The proposed system is compatible with existing rotary printing-machine arrangements, because it can be accommodated in the area in the printing units presently provided for plate changing in the printing machines.
In the construction disclosed in the aforementioned U.S. Pat. No. 5,713,287, after the printing job has been completed, the polymer coating which is able to be influenced must be removed again, at least for the most part, from the surface of the print carrier, before a new neutral coating, i.e., a coating not yet irradiated by a laser light source, is applied as a precondition for a printing image to be newly generated by forming an image on the printing form in the printing machine for the next printing job. Even if the polymer coating is not completely removed from the surface of the printing form cylinder after the preceding printing job has been completed, the adhesion of the polymer to be newly applied for the next printing job must be so good that the polymer coating for the following job has the same high residence time on the printing form with repeated reproducibility.
It has been found that the adhesion between the contact surface of the carrier material to which the polymer coating to be influenced is applied, as well as the polymer material to be influenced, in repeated application of the treatable polymer material, is inadequate for achieving the same high and consequently adequate residence time of the print carrier as is the case when the treatable polymer is applied for the first time.
Attempts have been made to improve the inadequate adhesion between the contact surface of the carrier material and the treatable polymer by improving the composition, i.e., the formulation, of the treatable polymer. Furthermore, attempts have been made to improve the adhesion between the contact surfaces by optimizing the cleaning process and the cleaning agents provided therefor. Attempts have also been made to increase the adhesion of the polymer by selecting different carrier materials and the nature of the surface thereof and the surface roughness thereof, respectively. Furthermore, parameters specific to the printing machine, such as, for example, the pressing together of mutually cooperating roller surfaces, and inks of differing viscosity have been used.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method and a device for producing a printing image carrier in prefabricated carrier material in a printing machine with which it is possible to provide economically a polymer coating that can be influenced for the printing and can be disposed of readily after the printing.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a method for producing a print carrier within a printing machine, which comprises providing on a cylinder of the printing machine a prefabricated carrier material having a contact surface, and, within the printing machine, applying an impressionable or influenceable polymer to the contact surface of the prefabricated carrier material.
In accordance with another mode, the method of the invention includes prefabricating the carrier material in roll form on winding spools.
In accordance with a further mode, the method of the invention includes prefabricating the carrier material as an exchangeable sleeve, with the contact surface thereof receiving thereon the impressionable or influenceable polymer coating.
In accordance with an added mode, the method of the invention includes prefabricating the carrier material by pre-cutting it into sheet form, and preparing the contact surface thereof for adhesion with the impressionable polymer coating.
In accordance with an additional mode, the method of the invention includes removing the carrier material pre-cut into sheet form from a jacket surface of the cylinder and applying the carrier material to the jacket surface, respectively, by an automatic changi
Dudding Alfred E.
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Locher Ralph E.
Meier Stephen D.
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