EP3418066A1

EP3418066A1 - Method for the production of an embossing tool for tactile structures

Info

Publication number: EP3418066A1
Application number: EP18000539.9A
Authority: EP
Inventors: Christian Schulze; Peter Franz; Hans-Joachim Kliem
Original assignee: Giesecke and Devrient Currency Technology GmbH
Current assignee: Giesecke and Devrient Currency Technology GmbH
Priority date: 2017-06-21
Filing date: 2018-06-19
Publication date: 2018-12-26
Anticipated expiration: 2038-06-19
Also published as: DE102017005838A1; EP3418066B1

Abstract

The invention relates to a method for producing an embossing tool, in particular a high-pressure plate for blind embossing, wherein tactile detectable structures are embossed into a substrate with the embossing tool.

According to the embossing tool is generated via a galvanic Abformweg from a gravure plate, wherein an embossing pattern is first introduced into a gravure plate and then the embossing tool is produced by galvanic molding of gravure plate, wherein the embossing motif on the embossing tool from one or more elevations on the front of the embossing tool and one or more directly opposite recesses on the back of the stamping tool.

Description

The invention relates to a method for producing an embossing tool, in particular a high-pressure plate for blind embossing, wherein tactile detectable structures are embossed into a substrate with the embossing tool.
In order to avert counterfeiting attempts, new security elements are constantly being searched for any data carriers that represent a value. This also applies to trademark protection. In this case, elements which have an embossed structure which are tactile to feel and therefore easy to check without aids are advantageous.
This embossing forms for gravure or high pressure are used. A special application here is the use of structures that are particularly clearly visible by persons with visual impairment. A particular embodiment in this case are the braille script or license plate, which are defined by typical points or line structures on the basis of the system or quantity, and represent, for example, a denomination of a banknote.
In intaglio printing, a special form of intaglio printing, a printing plate with recessed structures is used, which transmits high-pressure raised areas to the substrate to be embossed.
Out DE 102015009983 A1 is an embossing tool for producing a security element for a valuables item from a substrate, in particular a banknote, a label or an outer packaging, known, wherein in the surface of the embossing tool is an engraving for producing a tactile detectable structure is introduced. The tactile detectable structure here consists of a first embossed structure and a second embossed structure, wherein the second embossed structure is disposed within the first embossed structure. The first embossing pattern forms a base for the second embossed structure on which the second embossed structure is arranged. This results in a total of an embossed structure, which consists of a base, which is formed by the first embossing structure, wherein the base surrounds the second embossing structure, which in turn is arranged on the base.
At high pressure, milled, lasered, washed-out or etched embossing plates are used which, by means of a counter-pressure mold, produce a raised structure on the substrate by means of mechanical pressure. The mechanical pressure for embossing is exercised directly locally on the printing plate, this pressure being transferred to the printing unit and the corresponding bearings of pressure and counter-pressure cylinders and, if appropriate, further cylinders and this heavily loaded. This has an unfavorable effect on the service life and the frequency of maintenance of a printing and / or embossing machine, especially with punctiform embossed structures.
The invention is therefore the object of developing a generic embossing tool such that the disadvantages of the prior art. In particular, the selective pressure is to be transmitted to a larger area in order to manage with a lower mechanical pressure load for the various cylinders of a printing press or their bearings.
This object is solved by the features of the independent claim. Further developments of the invention are the subject of the dependent claims.
According to the embossing tool is generated via a galvanic Abformweg from a gravure plate, wherein an embossing pattern is first introduced into a gravure plate and then the embossing tool is produced by galvanic molding of gravure plate, wherein the embossing motif on the embossing tool from one or more elevations on the front of the embossing tool and one or more directly opposite recesses on the back of the stamping tool.
The recess on the back of the embossing tool distributes particularly advantageous the punctual pressure distribution, which acts on the increase on the front of the embossing tool on a larger area on the back of the embossing tool and thus relieves disposed on the back of the embossing tool further components on which the embossing tool is stretched.
According to a particularly advantageous embodiment, the embossing tool is a high-pressure plate for a blind embossing, in which the surface of the printing plate is not provided with color. In this case, only the elevations of the high-pressure plate are transferred into the substrate to be embossed, without transferring color to the substrate.
According to an advantageous embodiment, the embossing tool consists of a metal, in particular of nickel, copper or zinc, which is deposited on the intaglio plate with a galvanic deposition process and thus impresses the structures of the intaglio printing plate in an inverted manner.
According to a particularly advantageous embodiment, the embossing tool, in particular that of nickel, copper or zinc, has a thickness of approximately 200 microns to about 750 microns. Further embodiments also go well beyond these material thicknesses. Thicknesses of, for example, 10 mm may also be desired here. The length and width of the embossing tool is particularly advantageous in each case about 900 mm to about 1100 mm.
According to an advantageous embodiment, the recesses of individual elements on the back of the embossing tool have a depth of up to 0.5 mm, preferably about 0.1 mm, a diameter or a width of up to 1.6 mm, preferably 0.1 mm to 0.2 mm, and a distance from one another (edge to edge) of up to 4 cm, preferably 0.1 mm to 0.5 mm.
The embossing tool is preferably mounted on a steel cylinder as a support cylinder, wherein preferably between the embossing tool and steel cylinder, a PVC film is inserted with a thickness of about 0.5 mm.
In particular, machines can be used with this embossing tool which are suitable for holding, screwing, fastening, sucking, chucking, holding magnetically or bringing it to the steel cylinder by means of adhesion. These can be embossing devices, punching machines, folding machines, offset presses, high-pressure machines, lacquer machines with offset units or coating units, as well as digital printing machines or screen printing machines, which basically enable embossing. Furthermore, machines can be used which are flat / flat, round / flat or flat / round in the embossing design.
According to an advantageous embodiment, the geometries of the embossed structures, ie in particular the depth, width and length and the flank angle, the distance from each other and the distribution of the individual embossed structures on the embossing tool, adapted to the conditions of the embossing and the substrate to be embossed, as for example from the DE 102015009983 A1 is known.
According to an advantageous embodiment, the intaglio plate made of brass or plastic and the generation of milling structures or depressions in the brass or plastic plate with a mechanical milling head, a stylus or a laser.
Furthermore, it is also possible to use gravure plates which otherwise allow recesses, for example by washing out, etching.
Further advantages of the invention are that diverse geometries of the embossed structures can be created, which can be adapted to the particular shape of the substrate to a special degree. Furthermore, the high-pressure mold can also be used in machines that are not actually intended for a stamping process. Also, the embossed structures can be particularly finely implemented while cost-effective high runs are made with the same printed image. In addition, for long runs a particularly high resistance of the embossing tools. Likewise, the cheap duplication of the stamping tools is given with very high repeatability due to the galvanic impression.
Further surface treatments can increase the durability of the stamping tool, for example chrome plating.
The substrate into which the embossed structures are formed in the embossing process is particularly preferably made of paper made of cotton fibers, as used, for example, for bank notes or as a header material, or of other natural fibers or of synthetic fibers or of a mixture of natural and synthetic fibers, or of at least one plastic film. Further preferably, the substrate consists of a combination of at least two superimposed and interconnected different substrates, a so-called hybrid. Here, the substrate is made of, for example, a combination of plastic film-paper plastic film, ie a paper substrate is covered on both sides by a plastic film, or a combination of paper-plastic film paper, ie a substrate made of a plastic film on each of its covered by paper on both sides.
Other substrates can be used, which are particularly suitable for embossing, such as metal foils, thin foils, cardboard, surface-treated cardboard, laminated substrate.
The paper layer usually has a weight of 40 g / m 2 to 110 g / m 2 , preferably from 80 g / m 2 to 90 g / m 2 . Of course, depending on the application, any other suitable weight and strength may be used. The thickness of the substrate is preferably about 90 μm or more.
Value documents for which such a substrate or security paper can be used are, in particular, banknotes, stocks, bonds, certificates, vouchers, checks, high-quality admission tickets, but also other papers which are subject to counterfeiting, such as passports and other identification documents, and also cards such as credit cards. or debit cards whose card body has at least one layer of security paper, and also product securing elements such as labels, seals, blisters, packaging, folding boxes, leaflets and the like. The simplified term Value document includes all the above materials, documents and product security elements.
The terms "front side" or "back side" of an embossing tool are relative terms, which may also be referred to as "the embossing" and "the opposing" sides, and which constitute the overwhelming portion of the overall surface of the embossing tool. Specifically not included with these terms are the side surfaces of an embossing tool, which are negligible compared to the extent of the embossing tool and can not be provided with embossing elements or coatings.
It is understood that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations, without departing from the scope of the present invention, insofar as this is covered by the scope of the claims.
Reference to the following embodiments and the additional figures, the advantages of the invention will be explained. The embodiments represent preferred embodiments, to which, however, the invention should not be limited in any way. Furthermore, the representations in the figures of better understanding are highly schematized and do not reflect the realities. In particular, the proportions shown in the figures do not correspond to the conditions present in reality and serve exclusively to improve the clarity. Furthermore, the embodiments described in the following embodiments are reduced to the essential core information for the sake of clarity. In the practical implementation Much more complex patterns or images can be used.

Fig. 1: in Seitenansicht eine aus dem Stand der Technik bekannte Tiefdruckprägeform (linke Abbildung) und eine aus dem Stand der Technik bekannte Hochdruckprägeform (rechte Abbildung),
Fig. 2: in Seitenansicht eine gefräste Messingplatte (linke Abbildung) und das damit erzeugte erfindungsgemäße Prägewerkzeug (rechte Abbildung),
Fig.3: in Seitenansicht die Verteilung des mechanischen Drucks bei einem erfindungsgemäßen Prägewerkzeug.

Fig. 1: in side view, a known from the prior art Tiefdruckprägeform (left figure) and a known from the prior art high-pressure stamping mold (right figure),
Fig. 2: in side view a milled brass plate (left figure) and the embossing tool according to the invention (right figure) produced therewith,
Figure 3: in side view, the distribution of the mechanical pressure in an embossing tool according to the invention.

The Fig. 1 shows a side view of a known from the prior art Tiefdruckprägeplatte 1 with a recess 3 (left figure) and known from the prior art high-pressure impression plate 2 with a 4 increase (right figure). In the high pressure, a milled, lasered, washed or etched die 2 is used, which by means of a counter-pressure cylinder (not shown) by means of mechanical pressure, the raised structure 4 on a substrate (not shown) transmits, which is located between the high pressure impression plate 2 and the impression cylinder. The mechanical pressure is thereby exerted directly locally on the pressure plate 2, wherein this mechanical pressure is transferred to the printing unit and the corresponding bearing of cylinders. This has an unfavorable effect on the printing press, especially with punctiform embossed structures.
Fig. 2 shows a side view of the solution according to the invention. Here, a hemispherical recess 7 is milled by means of a corresponding milling geometry in a brass plate 5 (left figure). The subsequent galvanic impression in the desired plate thickness results in a stamping tool in the form of a high-pressure plate 6 with a corresponding elevation 8 on the front of the plate and a recess 9 on the opposite rear side (right figure).
Preferred enhancement reactions 8 involve blindness indicia having a diameter of elevation 8 in the direction of the disc surface between 1 mm and 2.5 mm. In particular, several increase 8 are introduced into the high-pressure plate 6.
Particularly preferably, the embossed structures in the high-pressure plate 6 are designed elongated, as for example from the DE 102015009983 A1 are known.
Fig. 3 shows in side view the particular advantage of the invention, according to which the mechanical pressure on the high pressure plate 6 during the printing process (symbolized by the thick arrow) not punctually linear down against the steel cylinder on which the high pressure plate 6 is clamped, takes place, but on the Edge of the recess 9 also distributed. This is symbolized by the four smaller arrows on the underside of the high pressure plate 6. This results in a larger area, on which distributes the force, and thus a lower mechanical pressure on the steel cylinder and the impression cylinder and their storage.
The distribution of the mechanical pressure during the embossing process is distributed at small dimensions of the recess 9 (0.1 mm height, 0.1 mm to 0.2 mm diameter or width and 0.1 to 0.5 mm distance from edge to edge) from the center of the recess 9 to the edge of the recess 9 back. For larger dimensions (0.5 mm height, 1.6 mm diameter or width and 1 cm distance from edge to edge) this will especially affect the edge of the outer recesses.

Claims

A process for producing an embossing tool, wherein the embossing tool tactile detectable structures are embossed in a substrate, characterized in that the embossing tool is produced via a galvanic Abformweg from a gravure plate, wherein initially an embossed motif is introduced into a gravure printing plate and then the embossing tool by galvanic Impression of the gravure plate is produced, wherein the embossing motif on the embossing tool consists of one or more elevations on the front of the embossing tool and one or more directly opposite recesses on the back of the embossing tool.
A method according to claim 1, characterized in that the embossing tool is a high pressure plate.
Method according to at least one of the preceding claims, characterized in that the embossing tool consists of nickel, copper or zinc.
Method according to at least one of the preceding claims, characterized in that the embossing tool has a thickness of about 200 microns to about 750 microns.
Method according to at least one of the preceding claims, characterized in that the depressions on the rear side of the embossing tool have a height of up to 0.5 mm, preferably about 0.1 mm, a diameter or a width of up to 1.6 mm, preferably 0.1 mm to 0.2 mm, and a distance from one another (edge to edge) of up to 4 cm, preferably 0.1 mm to 0.5 mm.
Method according to at least one of the preceding claims, characterized in that the embossing tool is mounted on a steel cylinder as a carrier cylinder, wherein preferably between the embossing tool and steel cylinder, a film of PVC is inserted with a thickness of about 0.5 mm.
Method according to at least one of the preceding claims, characterized in that the geometries of the embossed structures, ie in particular the depth, width and length and the flank angle, the distance from each other and the distribution of the individual embossed structures on the embossing tool, on the conditions of embossing and a to be adapted embossing substrate.
Method according to at least one of the preceding claims, characterized in that the intaglio printing plate made of brass or plastic, wherein the generation of the milling structures in the brass or plastic plate is carried out with a mechanical milling head, a stylus or a laser.
Method according to at least one of the preceding claims, characterized in that the gravure printing plate is etched or washed out.