METHOD AND DEVICE FOR PRODUCE A SAFETY PAPER WITH WATERMARK AND INTEGRATED WINDOW SAFETY ELEMENT

Description

[0001] The invention relates to a method and a device for producing a security paper with a watermark and an integrated window security element.

[0002] Security papers or valuable documents are often provided with authenticity features such as watermarks, embedded security threads and the like, which allow verification of the authenticity of the security paper or valuable document and at the same time serve as protection against unauthorized reproduction.

[0003] In the past, authenticity features that can only be incorporated into the security paper during production have proven successful, such as watermarks, chemically reacting additives, mottled fibers, or security threads fully or partially embedded in the security paper. Security threads that are neither fully applied to a surface of a security paper nor fully embedded in the security paper are referred to as window security threads. These are sometimes embedded in the security paper in such a way that they are only visible in certain window areas on one or both opposite surfaces of the security paper.

[0004] WO 2014 / 086476 A1 discloses a device for producing security paper, wherein a first wet end of a paper machine forms a first paper web and optionally provides it with individualization features, such as an opening. A suction device removes paper fibers from at least one location of the first and / or second paper web while it is still wet. WO 2007 / 042718 A1 discloses a rinsing device for security paper. DE 10 2005 04556 A1 uses a suction device to produce an opening in a paper web and shows the preamble of claim 1.

[0005] Based on this, the invention is based on the object of providing a simple and cost-effective method for producing a security paper of the type mentioned above. In particular, the method is intended to enable the production of security paper with an appealing visual appearance, in which watermarks and window security threads are combined in a novel way. The invention is also intended to provide a corresponding device.

[0006] According to the invention, a method for producing a security paper with a watermark and an integrated window security element is provided in which a first paper web is formed and provided with a watermark in a first paper layer production unit, and a second paper web is produced in a second paper layer production unit. The second paper web is brought together with the first paper web and firmly connected, wherein, when the paper webs are brought together, an endless security element is embedded between the first and second paper webs in the region of the watermark. By means of a rinsing device, paper fibers are removed from the second paper web while it is still wet, so that the endless security element is freely accessible in window regions of the second paper web.In the present case, a support surface of the flushing device, which is arranged on the side of the second paper web opposite an outlet device of the flushing device, has openings which are designed corresponding to the window regions, so that the window regions are created when the second paper web is subjected to surface-to-surface contact.

[0007] For the purposes of the invention, the term "security paper" refers to unprinted paper, which is usually available in a quasi-continuous form and is further processed at a later date. Security papers are used in particular for the production of valuable documents. A "value document" refers to a document that is ready for its intended use. Valuable documents within the meaning of the present invention include, in particular, banknotes, shares, bonds, certificates, vouchers, checks, high-value admission tickets, but also other documents at risk of counterfeiting, such as passports and other identification documents, as well as product security elements such as labels, seals, packaging, and the like. The simplified term "security paper" or "value document" hereinafter includes all such documents and product security devices.

[0008] The security paper is preferably multi-layered and comprises at least one layer of paper. The additional layer(s) can also be made of paper, but also of other materials, such as plastic films. The paper or a paper layer particularly preferably comprises cotton fibers, such as those used for banknotes.

[0009] For the purposes of the invention, a paper layer producing device is a device, in particular a sheet forming unit, for producing a paper web. The paper layer producing device can be a cylinder mold machine, in particular a countercurrent cylinder mold machine, a cocurrent cylinder mold machine, or a double cylinder mold machine. Furthermore, the paper layer producing device can be a fourdrinier machine. The paper web output by the paper layer producing device is preferably output as continuous paper. Alternatively, a paper sheet could be output. Furthermore, the paper layer producing device can comprise a nozzle for outputting a pulp mass onto a screening unit, for example a cylinder mold or a fourdrinier mold, whereby a paper web is produced.

[0010] The endless security elements of the present invention can be formed, in particular, by security threads or wide security bands. While security threads have a width of less than 4 mm, usually less than 2 mm, and typically approximately 1 mm, endless security elements with a width of 4 mm or more are referred to as security bands in this description. The security bands can, in particular, have a width of 4 mm to 20 mm, and in some cases even up to 30 mm. Even if the invention is explained below primarily using narrow security threads as an example, it is always understood that the security elements can also be formed by wide security bands. The embedding of wide security bands in paper production is described, for example, in the document EP 0625 431, the disclosure of which is incorporated into the present application in this respect.

[0011] The endless security element can, for example, be a security element with a color-shift effect, with a diffraction structure such as a hologram, with a dynamic effect, with a possibly partially recessed metallization, and / or with a printed image.

[0012] The window areas of the second paper web mentioned above are created precisely by removing the paper fibers from the second paper web. In an advantageous variant of the invention, the window areas of the second paper web are created in register with the watermarks of the first paper web. This means in particular that the shape and position of the window areas of the second paper web and thus also the paper areas left between the window areas are coordinated with the shape and position of the watermarks of the first paper web. Preferably, the shape and position of the window areas of the second paper web are even coordinated with the motif parts represented by the watermarks. For example, the window areas can cover first motif parts of the watermarks, while the paper parts left behind in the second paper web are congruent with second motif parts.Due to the additional paper thickness, the second parts of the watermark appear even darker and the first parts of the watermark appear lighter.

[0013] In this way, the window areas of the second paper web can reinforce or emphasize the visual impression of the watermarks of the first paper web. The shape of the window areas of the second paper web and the watermarks of the first paper web are advantageously related to each other, in particular, the window areas and the watermarks represent related or complementary information.

[0014] Since the continuous security element is embedded between the first and second paper webs in the watermark area and is also freely accessible in the window areas of the second paper web, the alignment of the window areas with the watermarks creates the impression for a viewer that the continuous security element runs inside the watermark, namely in the window areas above the watermark and in the remaining paper areas at least partially below the watermark. A security element running inside a watermark is unusual and therefore striking for the viewer, as well as highly recognizable.

[0015] In an advantageous variant of the invention, the paper fibers are removed from the second paper web before it is joined to the first paper web. The paper fibers are advantageously removed in register with the embedding position of the endless security element.

[0016] According to a further development, the first paper web is provided with a multi-level watermark by depositing the paper in the first paper layer producing device, in particular a cylinder-shaped paper machine, on a dewatering screen, the supporting screen of which has a multi-level relief in the form of the watermark to be produced in a partial area. The multi-level relief is advantageously formed by an injection-molded, perforated watermark insert, a deep-drawn, perforated watermark insert, or a hot-stamped, perforated watermark insert. The watermark insert can be designed, for example, as a bronze stamp.

[0017] A particular advantage of the described procedure is that the generation of the watermarks is decoupled from the generation of the window regions and the embedding of the continuous security element. In addition, the generation of the window regions by means of the aforementioned suction and / or rinsing device allows the shape and position of the window regions in the second paper layer to be precisely aligned with the shape and position of the watermarks in the first paper web. By embedding the security element between a first paper web of the first paper layer generation device, for example of a cylinder mold machine, in particular a direct current cylinder mold machine, and a second paper web, for example of a second paper layer generation device, for example a cylinder mold, an improved stack flatness of the security paper produced can also be achieved.

[0018] The invention also includes an apparatus for producing a security paper with a watermark and an integrated window security element, with a first paper layer producing device, in particular a cylinder mold machine, e.g. a direct-current cylinder mold machine, for forming a first paper web and for providing the first paper web with a watermark, a second paper layer producing device for producing a second paper web, a removal belt for merging and firmly connecting the second paper web to the first paper web, a device for feeding an endless security element in the region of the watermarks between the first and second paper webs when the paper webs are merging, and a rinsing device for removing paper fibers from the second paper web while it is still wet.

[0019] In this case, the flushing device comprises an endless belt with at least one recess, which is stretched over at least two position-adjustable guide rollers. The at least one recess in the endless belt corresponds to the window areas to be created in the second paper web.

[0020] The flushing device has an outlet device. The outlet device is designed to dispense a liquid and is directed towards the second paper web. Paper fibers can be specifically flushed away via the directed dispensing of the liquid, so that at least one recess is created in the second paper web. On the side of the second paper web opposite the outlet device, a receiving container for receiving the flushed paper fibers is provided. The outlet device can be designed to act on the second paper web geometrically in the shape of the recess. Furthermore, a support surface, which is arranged on the side of the second paper web opposite the outlet device, can have openings. The openings are designed to correspond to the recess, so that the recess is created when the second paper web is acted upon over its entire surface. In the present case, the support surface can be designed as the endless belt.

[0021] The endless belt can be formed from a sieve-like fabric, for example from plastic, copper or bronze, or can consist of a material that has a closed surface except for at least one recess.

[0022] The flushing device is advantageously arranged in the device between the second paper layer producing device and the merging position of the paper webs, so that the paper fibers can be removed from the second paper web before merging with the first paper web and embedding the second endless security element.

[0023] A multi-layer security paper or valuable document may include: a first paper layer with a grammage of 60 g / m 2< or more, in particular from 60 g / m 2< to 80 g / m 2< and a second paper layer firmly connected to the first paper layer with a grammage of 45 g / m 2< or less, in particular from 10 to 45 g / m 2< , a watermark, in particular a multi-level watermark in the first paper layer, and an endless window security element which is embedded between the first and second paper layers in the area of ​​the watermark and is freely accessible in window areas of the second paper layer.

[0024] In the present case, the shape of the window areas of the second paper layer and the watermarks of the first paper layer are particularly advantageously related to one another; the window areas and the watermarks each represent information that is related to or complements one another.

[0025] Advantageously, the window areas of the second paper layer are arranged in register with the watermark of the first paper layer. As explained above, this means, in particular, that the shape and position of the window areas of the second paper web, and thus also the remaining paper areas between the window areas, are coordinated with the shape and position of the watermarks of the first paper web, preferably even with the motif parts represented by the watermarks.

[0026] Further embodiments and advantages of the invention are explained below with reference to the figures, in which a true-to-scale and true-to-proportion reproduction has been omitted in order to increase clarity.

[0027] They show: Fig. 1 schematically shows a paper machine with a cylinder paper machine and a second paper layer producing device according to an embodiment of the invention, Fig. 2 the suction device of the paper machine of the Fig. 1 more precisely, Fig. 3 is a plan view of a section of a security paper according to the invention in cut form, and Fig. 4 is a section through the security paper of the Fig. 3 along line IV-IV.

[0028] The invention will now be explained using the example of the production of security paper for banknotes, which has a combination of a window security thread and multi-level watermarks of high detail. Figure 1 shows schematically a paper machine 10 with a first paper layer producing device, in the present example a cylinder-shaped paper machine 12, and a second paper layer producing device 14, preferably a second cylinder-shaped paper machine.

[0029] In the cylinder-shaped paper machine 12, preferably a cocurrent cylinder-shaped paper machine 12, a paper web 20 is formed on a cylinder-shaped screen 18 in a conventional manner. The first paper web has, for example, a grammage of 60 to 80 g / m². The cylinder-shaped screen 18 is a dewatering screen, the supporting screen of which is provided, in at least one partial area, with a multi-level relief in the form of the watermark to be produced. The multi-level relief is formed, in particular, by an injection-molded, perforated watermark insert, as described in more detail in the publication WO 2008 / 071325 A1.

[0030] Parallel to the production of the first paper web, a second, initially homogeneous paper web 30 is produced in the second paper layer production device 14 by spraying paper pulp onto the surface of a cylinder screen 44 using a headbox nozzle 42. The paper layer produced by the second paper layer production device 14 is very thin and has, for example, a grammage of only 10 to 25 g / m². The second paper web 30 is removed from the cylinder screen 44 by means of a removal felt 16, which can also be understood as a removal screen or removal belt, and is guided to the first paper machine 12, where it is joined to the first paper web 20 in the region of the pressure roller 36.

[0031] When the paper webs 20, 30 are brought together, an endless security element 32 is also unwound from a reel 34 and, when the two paper webs 20, 30 are joined, is embedded between the first 20 and second paper web 30 in the area of ​​the multi-level watermark.

[0032] Furthermore, a suction device 50 is arranged between the second paper layer generating device 14 and the pressure roller 36, which removes paper fibers from the second paper web 30 in the still moist state in register with the embedding position of the endless security element 32 and also in register with the multi-level watermarks of the first paper web 20.

[0033] The areas of removed paper fibers form window areas in the second paper web 30, in which the endless security element 32 is visible and freely accessible after being embedded between the two paper webs 20, 30. Furthermore, the window areas of the second paper web 30 complement the watermarks of the first paper web 20 and are particularly meaningfully related to them, as explained generally above and in more detail below using a specific embodiment.

[0034] Instead of or in addition to the suction device 50, a rinsing device 58 for removing paper fibers can be provided.

[0035] The interconnected paper webs 38 are then fed to further processing stations, such as calendering, sizing and the like.

[0036] The Fig. 2 The suction device 50 shown in more detail comprises an endless belt 52 made of a sieve-like fabric, which is mechanically tensioned taut by a series of position-adjustable guide rollers 54. The endless belt 52 has one or more recesses, the shape and size of which correspond to the window areas to be created in the second paper web 30. Arranged within the endless belt 52 is a slotted suction box 56, with which a negative pressure is generated on the endless belt 52, thereby sucking paper fibers out of the second paper web through the recesses in the belt 52 and the slot in the suction box 56.

[0037] Instead of a suction box 56, a suction roller or a tube suction device can also be used. For cleaning the belt 52, the suction device 50 can include a screen conditioning system (not shown in the figure) with cleaning spray pipes and tube suction devices.

[0038] A multi-layer security paper 60, as produced with the paper machine of Fig. 1 can be produced is in the Figures 3 and 4 shown in a cropped form. Fig. 3 a top view of a section of the security paper 60 and Fig. 4 shows a section through the security paper 60 along the line IV-IV of Fig. 3 in the area of ​​the embedded security thread 82.

[0039] The security paper 60 contains a first, thicker paper layer 70 with a grammage of 60 to 80 g / m², which is provided with a high-resolution, multi-level watermark 72, which in the exemplary embodiment is designed in the form of a sailing ship. The first paper layer 70 is firmly connected to a second, thinner paper layer 80, which has a grammage of only 10 to 45 g / m² and which is provided with window regions 84 whose shape and position are precisely matched to the high-resolution watermark 72. A window security thread 82 is embedded between the first and second paper layers 70, 80 and is visible and freely accessible in the window regions 84 of the second paper layer 80. When viewed from the opposite side of the security paper, i.e. from the side of the first paper layer 70, the security thread 82 is not visible when viewed from above.

[0040] The special feature of the combination of watermark 72, window areas 84 and security thread 82 lies in particular in the precise registration of the two elements, watermark and window areas, which is made possible by the above-described creation of the window areas 84 in the second paper layer 80. Specifically, the window areas 84 in the exemplary embodiment are designed in the form of a negative representation of the sails of the watermark 72, so that the paper areas 86 lying between the window areas 84 have the shape of the sails of the sailing ship represented by the watermark 72, while the window areas 84 themselves cover the spaces between the sails and the area of ​​the hull of the sailing ship.

[0041] By embedding the window security thread 82 between the first and second paper layers 70, 80 and matching the window regions 84 to the watermark 72, the thread 82 appears to an observer to run inside the watermark 72. Although the watermark 72 itself is present below the thread 82 in the first paper layer 70, the sail-shaped paper regions 86 of the second paper layer partially cover the thread 82 and therefore continue the visual appearance of the watermark 72 from the first paper layer 70 into the second paper layer 80. Since the window regions 84 in the second paper layer 80 can be produced with a desired shape and position using the suction device 50 described above, it is readily possible to precisely match the window regions 84 and, accordingly, the remaining paper regions 86 of the second paper layer 80 to the shape and position of the watermark 72 of the first paper layer 70.The result is a visually impressive design of a watermark, through the interior of which a window security thread appears to run. List of reference symbols

[0042] 10 Paper machine 12 First paper layer production device 14 Second paper layer production device 16 Take-off felt 18 Round wire 20 First paper web 30 Second paper web 32 Endless security element 34 Reel 36 Pressure roller 38 Interconnected paper webs 42 Headbox nozzle 44 Round wire 50 Suction device 52 Endless belt 54 Guide rollers 56 Suction box 58 Flushing device 60 Security paper 70 First paper layer 72 Watermark 74 Window areas 76 Further security feature 80 Second paper layer 82 Window security thread 84 Window areas 86 Paper areas

Claims

1. Method for producing a security paper having watermarks and an integrated window security element, in which method - a first paper web (20) is formed and provided with watermarks (72) in a first paper layer generating device (12), - a second paper web (30) is generated in a second paper layer generating device (14), and - the second paper web (30) is merged with the first paper web (20) and fixedly connected, wherein during merging of the paper webs an endless security element (32) is embedded in the region of the watermarks (72) between the first and second paper web, characterized in that paper fibres are removed from the second paper web (30) by means of a flushing device in a still wet state, so that the endless security element (32) in window regions (74, 84) of the second paper web (30) is freely accessible, wherein a contact face of the flushing device, which is disposed on the side of the second paper web (30) lying opposite an outlet device of the flushing device, has openings which are designed so as to correspond to the window regions (74, 84) in such a way that the window regions (74, 84) are generated when the second paper web (30) is impinged in a planar manner.

2. Method according to Claim 1, characterized in that the window regions (74, 84) of the second paper web (30) are generated in register with the watermarks (72) of the first paper web (20).

3. Method according to at least one of Claims 1 to 2, characterized in that the shape of the window regions (74, 84) of the second paper web (30) and the watermarks (72) of the first paper web (20) are in a meaningful context, in particular in that the window regions (74) and the watermarks (72) each represent mutually related or complementary information.

4. Method according to at least one of Claims 1 to 3, characterized in that the paper fibres are removed from the second paper web (30) prior to merging with the first paper web (20).

5. Method according to at least one of Claims 1 to 4, characterized in that the paper fibres are removed in register with the embedding position of the endless security element (32).

6. Method according to at least one of Claims 1 to 5, characterized in that the first paper web (20) is provided with a multi-stage watermark (72) in that the paper deposition in the first paper layer generating device takes place on a dewatering wire, the carrier wire of the latter having in a sub-region a multi-stage relief in the form of the watermark (72) to be generated.

7. Method according to Claim 6, in which the multi-stage relief is formed by an injection-moulded, perforated watermark insert, by a vacuum-formed, perforated watermark insert, by a hot-embossed, perforated watermark insert and / or formed by a conventional watermark insert.

8. Device for producing a security paper having watermarks and an integrated window security element, having - a first paper layer generating device (12) for forming a first paper web (20) and for providing the first paper web (20) with watermarks (72), - a second paper layer generating device (14) for generating a second paper web (30), - a collection wire for merging and fixedly connecting the second paper web (30) to the first paper web (20), - an apparatus for feeding an endless security element (32) in the region of the watermarks (72) between the first and the second paper web when merging the paper webs, characterized by - a flushing device (58) for removing paper fibres from the second paper web in a still wet state; and in that - the flushing device (58) has an endless belt (52) which has at least one clearance and is clamped to at least two position-adjustable guide rollers (54), and preferably furthermore has a flushing unit (56) for flushing out paper fibres through the at least one clearance of the endless belt.

9. Device according to Claim 8, characterized in that the flushing device (58) is disposed between the second paper layer generating device (14) and the merging position of the paper webs.