Printing – Planographic – Rotary machines
Patent
1997-01-14
1998-07-14
Fisher, J. Reed
Printing
Planographic
Rotary machines
1013501, 1013515, B41F 700, B41F 3106
Patent
active
057787751
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a printing unit of a rotary printing press with a short inking system for direct printing using a "waterless" planographic printing plate.
DESCRIPTION OF THE PRIOR ART
Printing units of rotary offset printing presses with short inking systems, wherein the ink to be printed on a paper web, is transferred indirectly by means of an offset cylinder--the rubber blanket cylinder--from a conventional, i.e. planographic printing plate provided with dampening agent, to a paper web are generally known.
It is disadvantageous here that changes in the measurements of the paper take place because of the dampening agents transferred to the paper.
SUMMARY OF THE INVENTION
The invention is based on the object of providing a printing unit with an inking system for direct printing by means of a "waterless" planographic printing plate.
In accordance with the present invention, a printing unit of a rotary printing press utilizes a "waterless" planographic printing plate that is secured on a printing cylinder. The printing unit is provided with a short inking unit that includes a structured ink transfer roller and a doctor blade device. This short inking unit cooperates with the "waterless" planographic printing plate. A second printing cylinder, that is equipped with a second "waterless" planographic printing plate is provided and acts as the counterpressure cylinder for the printing unit.
The advantages which can be achieved by means of the present invention reside, in particular, in that paper warping because of dampening agents does not occur. Since no dampening agents are used, an assured ink transfer which remains constant is assured.
The printing cylinder with the soft "waterless" planographic printing plate takes over the function of the otherwise customary rubber blanket cylinder, and provides, for example, an even transfer of the pressure force even with rough paper.
It is particularly advantageous that, because the rubber blanket cylinder is no longer needed, there is only one ink transfer point between the planographic printing plate and the material to be printed, because of which less re-splitting and squeezing out of the printing ink takes place. Because of this, it is possible to transfer thicker printing ink layers, which elsewhere are only achieved in connection with rotogravure or screen printing processes. Besides this, the present printing unit, without a rubber blanket cylinder, is considerably cheaper than comparable offset printing systems.
The use of a short inking system without ink zones for inking this "waterless" planographic printing plate is particularly advantageous, since, in this case, adjustment work for maintaining the ink transfer constant are omitted. In addition, the amount of waste is minimized. The simple construction makes maintenance work easier and the investment costs are extremely low.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention are represented in the drawings and will be described in more detail below.
Shown are in:
FIG. 1, a schematic representation of a first preferred embodiment of a printing unit in accordance with the present invention with a short inking system;
FIG. 2, a schematic section through a planographic printing plate;
FIG. 3, a portion of a schematic section of a structured ink transfer roller;
FIG. 4, a schematic representation of a second preferred embodiment of a printing unit in accordance with the invention with a short inking system; and
FIG. 5, a schematic representation of a third preferred embodiment of a printing unit in accordance with the invention with a short inking system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A printing unit 2, in accordance with a first preferred embodiment of the present invention, and consisting of two printing cylinders 3, 4, wherein the second printing cylinder 4 acts as a counter-pressure cylinder for the first printing cylinder 3, is seated in lateral frames 1 of a rotary printing press. This printing unit 2 is shown i
REFERENCES:
patent: 3587463 (1971-06-01), Granger
patent: 3613578 (1971-10-01), Heurich
patent: 4208963 (1980-06-01), Dahlgren
patent: 4407196 (1983-10-01), Matalia et al.
patent: 4805530 (1989-02-01), Kobler
patent: 4903599 (1990-02-01), Kubler
patent: 5053311 (1991-10-01), Makino et al.
patent: 5272971 (1993-12-01), Fredericks
Fisher J. Reed
Koenig & Bauer--Albert Aktiengesellschaft
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