DE20020797U1 - Device for producing plastic prints on offset printing machines - Google Patents

Abstract

A conventional printing machine, consisting of at least two printing turrets (31-34) with at least one following arrangement doping unit for applying a final finishing layer. The printing turrets are provided for the squeezing of at least two ink systems, deviating from each other, concerning their absorption ability for the final doping layer. One of these ink systems is provided for the printing of significant prominent making printed image components. Optional driers (111) are assigned to the printing mechanisms (31-34) and for the application of the final doping layer, a doping unit (4) is arranged following the printing mechanism.

Description

Device for producing three-dimensional prints on offset printing machines

The invention relates to a device for producing three-dimensional prints on offset printing machines, in which the plasticity of the prints is achieved by significantly increasing the degree of gloss of the print image components to be emphasized.

To create three-dimensional prints, printing processes are generally used. One of these processes is screen printing. In this process, the colors are applied to the printing material through a fine-mesh screen, with the non-printing areas closed off by a stencil. This allows for a stronger application of color to the areas of the print image that are to be emphasized, so that a three-dimensional appearance can be achieved.

This process is unproductive and uneconomical due to the high ink consumption.

The object of the invention is to develop a device for producing three-dimensional prints, by means of which the previously common screen printing process can be replaced in some areas by the more economical offset printing process.

According to the invention, the object is achieved by the features of the first claim.

The invention has the advantage that printed images can now be produced using an offset printing process that have optically exposed contours with little use of material.

The invention will be explained in more detail using an embodiment. The accompanying drawing shows a sheet-fed offset printing machine in a series design.

As can be seen from the figure, this sheet-fed offset printing press consists of several printing units 31 to 34 arranged in series. In the exemplary embodiment, four printing units 31 to 34 are shown as an example, whereby at least two printing units are required.

A feeder 1 is arranged in front of the printing units 31 to 34. The structure and function of the feeder 1 are known, so that it does not need to be discussed in more detail here. The printing units 31 to 34 each consist of an impression cylinder 21 to 24, a plate cylinder 5 and a blanket cylinder 6 (plate cylinder 5 and blanket cylinder 6 are only shown in the figure in the printing unit 31). The direction of sheet travel is indicated by an arrow. The sheet feeders enclosed by two impression cylinders 21 to 25 are also visible.

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guide cylinders 71 to 74, which can also be designed as a turning drum in a printing press that can be used for perfecting. Impression cylinders 21 to 24 and sheet guide cylinders 71 to 74 are sheet-guiding cylinders with a double-large diameter. The inking and dampening units belonging to each printing unit 31 to 34 are not shown here.

The printing units 31 and 32 shown here are intended for printing an ink system that contains inks with radiation-drying - usually UV-drying - components. The printing units 33 and 34 are intended for printing other inks, for example inks that are typical for offset printing.

In the exemplary embodiment, a dryer 111 is assigned to the printing unit 32. This dryer 111 is selected according to the ink system to be dried, so that a UV dryer is used at this point.

A coating tower 4 is arranged in the sheet travel direction after the printing units 31 to 34. This consists of the impression cylinder 25, to which the coating form cylinder 8 is assigned. A coating plate 81 is clamped onto the coating form cylinder 8. The coating tower 8 serves to cover the printed image with a coating layer, which is also radiation-drying here.

An anilox roller 9 is assigned to the coating form cylinder 8 or the coating plate 81. A chamber doctor blade 10 is used to supply this anilox roller 8 with paint. A dryer 112 is also assigned to the coating tower 4.

A delivery 12 is provided after the coating tower 4. The structure and function of the delivery 12 are known, so they will not be discussed in more detail here.

How the device works:

The printed sheet provided in the feeder 1 is grasped by devices not described in detail here and fed onto the sheet path. In the printing units 31 to 32, the ink of an ink system is applied via the blanket cylinder 6, which contains a proportion of an ink that hardens under radiation (in the example under ultraviolet radiation). Such inks are referred to as hybrid inks. It is also possible to use pure UV inks at this point.

The color systems here refer to colors that have essentially the same processing properties.

This ink layer can then be dried by the dryer 111 before the printed sheet is passed on to the following printing units 33 and 34. Here, the printed sheet is printed with the colors of a different color system, for example with a color system that consists of colors typical for offset printing.

Finally, in the coating tower 4, varnish is applied over the entire surface by the varnish plate 81. This varnish has the property that it interacts with the color systems in different physical and/or chemical ways and thus has a divergent effect on the gloss level of the color layer. In the example, a colorless varnish is used which, like the hybrid colors, hardens under UV light. The dryer 112, which is designed here as a UV lamp, is used for this purpose. The color layer, which represents the printed image components to be highlighted, therefore appears high-gloss, while the color layer, which is formed by the colors typical for offset printing, appears dull.

One of the possible prerequisites for the above-mentioned effect to occur is that the paint systems differ from one another in terms of their paint absorption capacity. The degree of gloss is inversely proportional to the paint system's absorption capacity for the paint, with paint layers with paint systems with lower absorption capacity having more paint remaining on their surface and paint layers from paint systems with higher absorption capacity having a higher proportion absorbed by the paint layer. The gloss-determining components of the paint are absorbed by the paint layer.

However, the invention is not limited exclusively to the differences in the absorption capacity of the lacquer layer described above. Rather, it covers all ink systems that specifically change the gloss level or gloss effect of the lacquer layer when interacting with it. It is not necessary for the sheet or the substrate to be dried and/or hardened by applying energy after printing. Other process-technical treatments of the ink layers and/or the lacquer layers are also possible in order to achieve the physical and/or chemical interaction to achieve the diverging gloss levels of the final lacquer layer.

In another embodiment of the invention, a process-technical treatment can be dispensed with in whole or in part. The above-mentioned effects can also be achieved by choosing the appropriate color systems and the corresponding varnish.

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List of reference symbols used

Investors

21 22 23 24 25

31 32 33

71 72 73 74 years

10

111

y Impression cylinder

Printing unit

Lacquer tower

5 plate cylinders

6 blanket cylinders

Sheet guide cylinder

8 paint form cylinders

81 Lacquer plate

Anilox roller

Chamber doctor blade

dryer

Claims (5)

1. Device for producing three-dimensional prints on offset printing machines, characterized in that a conventional printing machine consisting of at least two printing towers ( 31 , 32 , 33 , 34 ) with at least one downstream varnishing device is provided for applying a final varnish layer, wherein the printing towers ( 31 , 32 , 33 , 34 ) are provided for printing at least two color systems that differ from one another with regard to their absorption capacity for the final varnish layer, one of these color systems is provided for printing the print image components that are to be significantly emphasized, dryers ( 111 ) are optionally assigned to the printing units ( 31 , 32 , 33 , 34 ), and a varnishing device ( 4 ) is arranged downstream of the printing units ( 31 , 32 , 33 , 34 ) for applying the final varnish layer. 2. Device for producing three-dimensional prints on offset printing machines according to claim 1, characterized in that the ink systems for printing the print image components to be significantly emphasized consist of hybrid inks which partially contain a radiation-curing ink and the other ink systems consist of inks typical for offset printing. 3. Device for producing three-dimensional prints on offset printing machines according to claim 1, characterized in that a coating tower ( 4 ) equipped with a coating form cylinder ( 8 ), an anilox roller ( 9 ) and a chamber doctor blade ( 10 ) is arranged as the coating device. 4. Device for producing three-dimensional prints on offset printing machines according to claims 1 and 3, characterized in that a varnish which can be cured under the action of radiation can be applied to the printing material by the varnishing device ( 4 ). 5. Device for producing plastic-looking prints on offset printing machines according to claim 1, 3 and 4, characterized in that the varnishing device ( 4 ) is assigned dryers ( 112 ) which generate UV radiation for drying and curing the varnish layer.