DK3208088T3

DK3208088T3 - DEVICE FOR HEAT FILM COATING

Info

Publication number: DK3208088T3
Application number: DK17152360.8T
Authority: DK
Inventors: Hans Schadl
Original assignee: Heidelberger Druckmasch Ag
Priority date: 2016-02-18
Filing date: 2017-01-20
Publication date: 2019-03-11
Also published as: EP3208088A2; DE102016202476A1; EP3208088B1; EP3208088A3

Description

The invention relates to a device for hot-foil stamping according to the preamble of claim 1.

Prior art

So-called hot-foil stamping belongs inter alia to the well-known sorts of finishing in the printing industry.

Mirror-finished planar elements in gold, silver, copper, aluminium and other metallic colours can be transferred in a hot-foil stamping printing procedure onto the print substrate. A carrier film is coated with the colouring layer and a heat-meltable adhesive (adhesive layer). Under the action of pressure and heat, the picture can be transferred with a heated stereotype (letterpress plate). Suitable machines are either rotative processing stations in printing machines or flatbed punch and/or stamping machines. The hot-foil stamping is used primarily in a wide assortment of sheet and roll products, such as packings for cosmetics, confectionary and beverages and for high-quality brochures.

In DE 10 2009 019 590 Al is described a rotative hot-foil stamping station, which is shown in its figure 8. Document EP-A-2 886 360 discloses a device according to the preamble of claim 1.

Disadvantageous in devices of this sort for hot-foil stamping is the high cost and time expenditure involved in the manufacture of the tools, that is the stereotypes for a respective order.

Task definition

Task of the present invention, therefore, is the creation of a device for hot-foil stamping which does not have the disadvantages of the prior art and facilitates a hot-foil stamping in only one processing station without expensive stamping tools individual to each order.

This task is solved with a device for hot-foil stamping with the characteristics of claim 1. The device according to the invention for hot-foil stamping on print substrates, such as sheets or webs, in particular made of paper, cardboard or plastic, includes a stamping element, a counter-pressure element assigned to this stamping element and a device for providing stamping foil. According to the invention, the device includes a laser unit for partially heating stamping foil in the region of the stamping elements, wherein the stamping element is formed transparent such that the laser beams of the laser unit penetrate through the stamping element and the stamping foil is partially heated at the desired points. The advantage of this device is that no tools need to be created specifically for the order. In this way, it is possible within a very short time to change the pattern of the hot-foil stamping. This means that a motive can also be altered during on-going production. By means of the direct heating of the stamping foil it is ensured that the hot-foil stamped motive has a high degree of contour sharpness.

The device according to the invention includes a control unit at least for actuating the laser unit. Additionally, a sensor having a data communication link with the control unit is provided to monitor the print substrate such that a precise controlling of the laser unit can be achieved. In this way, the hot-foil stamping can be applied precisely to a printed picture which has already been printed on the print substrate.

In an advantageous further development of the device according to the invention, the stamping element is made of glass. The counter-pressure element can have a rubber-coated surface.

In a first embodiment variation, stamping element and counter-pressure element are designed respectively as cylinders, in a second embodiment variation, stamping element and counter-pressure element are designed respectively as plates.

In the first embodiment variation, a cooling device can be provided adjacent to the stamping cylinder.

The described invention and the described advantageous further developments of the invention constitute also in combination with one another - inasmuch as this is technically sensible - advantageous further developments of the invention.

With respect to further advantages and developments of the invention advantageous in constructional and functional respect, reference is made to the subclaims and the description of embodiment examples with reference to the accompanying figures.

Embodiment example

The invention is to be described in still more detail with reference to attached figures. Elements and components corresponding to one another are labelled in the figures with the same reference signs. In order to achieve an improved visibility of the figures, no true-to-scale representation has been made. In schematic representation: figure 1 shows a first embodiment variation of a device according to the invention for hot-foil stamping figure 2 shows a second embodiment variation of a device according to the invention for hot-foil stamping figure 3 shows a printing machine in an overview representation.

Figure 3 shows as an example of a processing machine 100 a rotary printing machine for printing a substrate web 1. The substrate web 1 is here transported in transport direction T through a plurality of processing facilities and hereby processed. The processing facilities are conventional printing facilities 11, a digital printing facility 14, a stamping facility 12 and a punching and scoring facility 13. Adjacent to the web run of the substrate web 1, one (or also several) inspection system 4 can be provided which is for example in the form of a camera, in order to monitor continuously the substrate web 1.

Instead of the conventional embossing facility 12, a device for hot-foil stamping 10, such as described hereinafter, can come into use.

Especially advantageous is the use of a device of this sort for hot-foil stamping 10 in processing machines 100 which have exclusively digital processing stations.

Figure 1 shows a first embodiment variation of the device for hot-foil stamping 10 which provides cylinders as processing tools: the device 10 includes a transparent cylinder 21 and a counter-pressure cylinder 16. The counter-pressure cylinder 16 can here be rubber coated. Through the pressure gap between the transparent cylinder 21, for example in the form of a glass cylinder, and the counter-pressure cylinder 16, both a substrate web 1 and a foil 2 are guided. Provision and guiding of the film web 2 are carried out by a device, not shown in more detail, having transport rollers for providing stamping foil. Within the transparent cylinder 21 is disposed a laser unit 19 which is controlled by a control unit 3 (not shown here). The laser beams 20 emitted by the laser unit 19 penetrate the transparent cylinder 21 and heat in a targeted and local manner the foil 2. At this locally heated point, metal particles can then be transferred from the carrier foil 2 onto the substrate web 1 and are "ironed-on" to the substrate web 1 by reason of the pressing force F between transparent cylinder 21 and counter-pressure cylinder 16, which results in the generation of the hot-foil stamping.

In figure 2 is shown an alternative embodiment form of the device for hot-foil stamping 10. Instead of the cylinder, here plates are used, specifically a transparent plate 22 as stamping element, which can be in the form of a glass plate, and a counter-pressure plate 23 as counter-pressure element. Also here, the counter-pressure plate 23 can have a rubber coated surface.

While the variation equipped with cylinders 16,19 according to figure 1 facilitates a continuous processing of a print substrate 1, with the embodiment variation according to figure 2 having the plates 22, 23, only a discontinuous processing of the print substrate 1 can be achieved. This means, for each stamping procedure, the print substrate 1 must be stopped for a short time.

List of reference signs 1 substrate web (print substrate) 2 foil 3 control unit (machine controlling with interface) 4 inspection system 10 device for hot-foil stamping 11 printing facility 12 stamping facility 13 punching and scoring facility 14 digital printing facility 15 print cylinder 16 counter-pressure cylinder 17 stamping cylinder 18 punching cylinder 19 laser unit 20 laser beam 21 transparent cylinder (glass cylinder) 22 transparent plate (glass plate) 23 counter-pressure plate 24 cooling device 100 printing machine F pressing force T web transport direction

Claims

Apparatus (10) for hot foil embossing on sheets or webs (1) on which an image has already been printed, with an embossing element (21, 22), a counter-embossing element (16, 23) and a device for providing embossing foil (2) ), the apparatus having a laser unit (19) for partially heating embossing film (2) in the region (21, 22) of the embossing element, and the embossing element (21, 22) being transparent, characterized in that the apparatus has a control unit (3) at least for controlling the laser unit (19) and the apparatus having a sensor (4) associated with the data transfer technology (4) for monitoring the sheets or webs (1) and for controlling the laser unit (19) in register so that the hot foil embossing is applied on the sheets or webs (1) in register with the image already printed.

Apparatus for hot foil embossing according to claim 1, characterized in that the embossing element (21, 22) is made of glass.

Apparatus for hot foil embossing according to one of the preceding claims, characterized in that the counter-embossing element (16, 23) has a rubberized surface.

Apparatus for hot foil embossing according to one of the preceding claims, characterized in that the embossing element (21) and the counter-embossing element (16) are each formed as a cylinder.

Apparatus for hot foil embossing according to claim 4, characterized in that a cooling device is arranged adjacent to the embossing cylinder (21).

Apparatus for hot foil embossing according to one of claims 1 to 3, characterized in that the embossing element (22) and the counter-embossing element (23) are each formed as a plate.

A printing machine (100) having at least one printing plant (11) and downstream thereof with an apparatus (10) according to one of the preceding claims.

A printing machine (100) according to claim 7 designed as a digital printing machine.