Patent Application
20060048657
The present invention relates to an apparatus and method for improving or optimizing the characteristics of wetting water in offset and roto-offset printing machines.
In an offset printing method, the printing operations are performed by a plate cylinder, cooperating with a blanket cylinder, therebetween the material to be printed upon is caused to pass, said material being conventionally in a sheet form (for the offset printing) or in a coil form (for the roto-offset printing).
In such a method, it is very important to optimize the wetting characteristics of the material to be printed upon, to provide a high printing quality.
In fact, as is known, the printing wetting water must have target pH and conductivity values and, moreover, it must be held at a constant preset temperature.
The above mentioned functions are conventionally performed by refrigerating devices, the so-called “recirculating” apparata.
Accordingly, the aim of the present invention is to provide such an apparatus, in particular an apparatus already disclosed in a prior Italian Patent Application No. MI20004A 000484, in the name of the same Applicant, for improving or optimizing the characteristics of wetting water in offset printing, allowing to automatically control or monitor the wetting water pH and conductivity values, in a fully independent manner.
Within the scope of the above mentioned aim, a main object of the present invention is to provide such an apparatus which allows to perform printing operations with a very high efficiency and stability.
Yet another object of the present invention is to provide such an apparatus in which it is not necessary to periodically replace the printing wetting water.
According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by an apparatus for improving characteristics of wetting water in offset printing machines, characterized in that said apparatus comprises coarse pre-filtering means, separating means defining one or more separating basins, ink recovering means arranged at a top of one or more of said separating basins, and empting valves.
According to a further aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are further achieved by a method for improving the characteristics of wetting water in offset printing machines, characterized in that said method comprises the steps of separating and trapping inks, foam and printing residues such as paper, solvents and so on, coming from return water returning from printing elements, to be conveyed, by a gravity fall or reconveying stations, to a recirculating unit.
Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred, though not exclusive, embodiment of the invention, which is illustrated, by way of an indicative, but not limitative, example in the accompanying drawings, where:
With reference to the number references of the above mentioned figures, the apparatus according to the present invention, which has been generally indicated by the reference number 1, is applied to an offset printing machine, generally indicated by the reference number 110, which comprises, in a per se known manner, a plurality of printing units 2, a recirculating device 3 and an apparatus 4 for improving or optimizing the wetting water, in particular of a type already discloses in a prior Italian Patent Application No. MI2004A 000484 in the name of the same Applicant.
In the offset printing machine shown in
More specifically, the liquid, after having being suitably refrigerated, is delivered to the printing unit 2 and then being conveyed to the apparatus 1 according to the present invention.
This apparatus 1 essentially comprises a coarse pre-filtering system, constituted by a pre-filter 5, a plurality of separating walls 6 defining one or more processing basins, generally indicated by the reference number 7, ink recovery tubes 8, for recovering ink, said tube being arranged on the top of the processing basins 7, and empting or outlet valves 9.
According to a modified embodiment of the invention, the apparatus, schematically shown in
The system according to the present invention operates as follows.
The return water, coming from the printing units 2 is conveyed to the ink separating device, by passing through the coarse pre-filtering system 5, 105 to then flow, through a forced flowing path, including the separating walls 6 (
The thus processed water is then sent by gravity falling to the apparatus 1 or is reconveyed by a pump 113, in the apparatus 101, to the recirculating device 3 to be again reconveyed to the printing units 2.
Thus, periodically, the operator can recover the residues or waste materials accumulated in the separating device basins, by an overflowing type of operation, i.e. by a simple downward turning of one or more pipes 14, as is schematically shown in
For fully empting the system, and accordingly to perform an extraordinary maintenance, are used the bottom empting valves 9 or 109.
It is practically found that the invention fully achieves the intended aim and objects.
In fact, the invention provides an apparatus in which it is not necessary to periodically replace the wetting water, since it is continuously and extraordinarily held in a clear condition.
In practicing the invention, the used materials, as well as the contingent size and shapes, can be any, depending on requirements.
| Number | Date | Country | Kind |
|---|---|---|---|
| MI 2004 A 001698 | Sep 2004 | IT | national |
