EP3247570B1 - Data storage medium having a window security thread - Google Patents

Description

The invention relates to a data carrier, in particular a value or security document, comprising a substrate comprising at least one paper layer with an embedded window security thread. The invention also relates to a dewatering screen for the manufacture of security paper with a window security thread.

Data carriers, such as banknotes, stocks, bonds, certificates, vouchers, checks, high-quality admission tickets, but also other forgery-prone papers, such as passports or other identity documents, are often provided with security elements for security, which allow a verification of the authenticity of the value document and at the same time serve as protection against unauthorized reproduction. The security elements can be designed in the form of a security thread which is wholly or partially embedded in the data carrier.

The introduction of a security thread in banknote paper, for example, in WO 2004/050991 A1 described. In this case, the security thread is unrolled during the manufacturing process of the paper from a driven roller and ensured by monitoring the tension of the security thread constant mechanical tension.

Window security threads are security threads that are neither applied to a surface of a data carrier substrate nor fully embedded in the substrate. Rather, they are partially embedded in the substrate such that they are visible on one or both opposite surfaces of the substrate only in certain window areas.

In order to obtain data carriers with window security threads, usually bronze mesh fabrics with brass stamping dies are in a mold with several Bars brought to create support surfaces for the security thread to be introduced in the papermaking process. From the designer's perspective, however, the possible designs are very limited and all known types of window threads have windows which are open over the entire thread width.

document WO 00/39391 discloses a data carrier according to the preamble of claim 1.

Proceeding from this, the present invention seeks to provide a data carrier of the type mentioned above with an attractive appearance and high security against counterfeiting. The invention is also intended to provide a suitable apparatus and method for making such data carriers.

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 invention, it is provided in the case of a generic data carrier that the window regions comprise at least one group of several microfine stars juxtaposed in the transverse direction of the thread, which are produced by paper-making and have an edge produced during papermaking with characteristic irregularities.

In this case, the statement that several micro-windows of a group in the transverse direction of the thread are next to one another more exactly means that there is a straight line in the transverse direction of the thread which cuts all the microphone windows of the group. The straight line is usually not clearly defined, it is only important that such a straight line exists. The definition clarifies the vivid understanding of adjacent microphone windows, as it ensures that the micro-windows have a certain overlap in the "side-by-side" direction indicated by the straight line.

The term window security thread is used in the present description not only for narrow security threads with a width of 4 mm or less, but also for wide security threads with a width of 4 mm to about 30 mm, which are sometimes referred to in the patent literature as security tapes , The embedding of such wide security threads in papermaking is for example in the document EP 0 625 431 A1 described.

In the context of the invention, all window areas of a data carrier can be designed in the form of micro-windows or the data carrier can also have conventional window areas in addition to micro-windows. Also, the window areas may not only comprise a named group, but rather several groups of adjacent micro windows are advantageously provided. It is even possible that all microphone windows are part of one or more such groups.

Advantageously, the window regions comprise at least one group with three or more, preferably five or more, micro-fiber stars adjacent to one another in the transverse direction of the thread.

In at least one group of juxtaposed micro-windows, the micro-windows are preferably offset from one another along the thread longitudinal direction so that they are not at the same height, but that there is a straight line in the cross-thread direction which intersects all the micro windows of the group. If a group of adjacent microphone windows contains N micro-windows, where N ≥ 2, then by definition there is a straight line g that intersects all microphone windows. For each microfine window i with i = 1, 2, ... N, a height hi and an offset di to the line g can be specified. As explained in more detail below, the reduced offset δ _i = di / h for each microphone window is smaller in magnitude than a maximum distance value δ _max , which in some embodiments may be equal to 0.5, but is advantageously less than 0.5, and preferably between 0.2 and 0.4. Smaller values of δ _max lead to a larger overlap of the micro-windows along the line g and therefore also produce a stronger sense of belonging to the group.

gilt. Da der maximal mögliche gegenseitige Mindestversatz bei N Mikrofenstern δ_max/ (N-1) ist, können auch schärfere Bedingungen an die Versatzwerte der Mikrofenster gestellt werden, also $$\left|{\mathrm{\delta }}_{\mathrm{i}}-{\mathrm{\delta }}_{\mathrm{j}}\right|\ge \mathrm{k*}{\mathrm{\delta }}_{\max }/\left(\mathrm{N}-1\right)\mathrm{für\; alle\; Paare\; i},\mathrm{j\; mit\; i}\ne \mathrm{j}$$

mit 1 ≤ k ≤ 2.The reduced offset is advantageously as different as possible for different microphone windows in order to optimally utilize the available offset clearance under the boundary condition of a juxtaposed position of the microphone windows. In particular, the micro windows advantageously have a minimum offset of at least δ _max / (N-1) against each other, so that is $$\left|{\mathrm{\delta }}_{\mathrm{i}}-{\mathrm{\delta }}_{\mathrm{j}}\right|\ge {\mathrm{\delta }}_{\mathrm{Max}}/\left(\mathrm{N}-1\right)\mathrm{for\; all\; couples\; i}.\mathrm{j\; with\; i}\ne \mathrm{j}$$

applies. Since the maximum possible mutual minimum offset for N micro star is δ _max / (N-1), sharper conditions can be applied to the offset values of the micro windows, ie $$\left|{\mathrm{\delta }}_{\mathrm{i}}-{\mathrm{\delta }}_{\mathrm{j}}\right|\ge \mathrm{k\; *}{\mathrm{\delta }}_{\mathrm{Max}}/\left(\mathrm{N}-1\right)\mathrm{for\; all\; couples\; i}.\mathrm{j\; with\; i}\ne \mathrm{j}$$

with 1 ≤ k ≤ 2.

The width of the micro-windows of the at least one group is advantageously less than 50%, preferably less than 40%, particularly preferably less than 30% of the thread width, in the transverse direction of the thread.

The length of the micro-windows parallel to the yarn longitudinal direction (sometimes also referred to as the height of the micro-windows) is advantageously between 0.2 mm and 4 mm, preferably between 0.3 mm and 3 mm and particularly preferably between 0.5 mm and 1 mm. Alternatively or additionally, the width of the micro-windows in the transverse direction of the thread is preferably between 0.2 mm and 4 mm, preferably between 0.3 mm and 3 mm, particularly preferably between 0.5 mm and 1 mm.

The at least one group preferably comprises micro-windows whose outlines represent patterns, characters or an encoding, in particular a letter or number sequence, such as a currency symbol or a value number. In particular, with wide security threads, the micro-windows can also be designed in the form of a facial or portrait representation.

In advantageous embodiments, the window areas comprise a plurality of microfine stars whose spatial arrangement forms a motif. The individual micro-windows are not necessarily formed even in motif form, but said motif is formed by the arrangement of the totality of micro-windows. Such a motif may consist in particular of letters, characters or figures which are composed of the micro-star stars as small building blocks. The outlines of the micro-windows can be the same or different. It is also possible that both the outlines of the microphone windows and their spatial arrangement each represent a motif or information. These motifs or information may be related or mutually exclusive to supplement a total information. The micro windows can also form screened, point cloud or strip windows.

In a further development of the invention, the micro windows as thin spots in the paper layer of the substrate are part of a laterally projecting beyond the window security thread watermark. In this way, the microphone windows can be integrated into a comprehensive design of the data carrier, so that the attention value and the imitation security further increases. In particular, the watermark may supplement, continue or repeat in the same or modified form a motif formed by the outline or the spatial arrangement of the microfine windows.

According to another, likewise advantageous development of the invention, a motif formed by the outline or the arrangement of the micro-windows is continued by any other security feature beyond the window security thread. The other security feature may consist, for example, in a print layer, a color layer, a laser cut area, a watermark, a film or a hologram. Even with such an embodiment, the other security feature can complement a motif formed by the outline or the arrangement of the micro-windows, continue or repeat in the same or modified form.

The window security thread is advantageously provided with diffraction structures, liquid crystal layers, thin-film structures, recesses in opaque, in particular metallic layers, fluorescent substances, magnetic, conductive and / or metallic layers.

The invention also includes a dewatering screen for the manufacture of security paper with a windowed security thread that on certain Window areas on a surface of the security paper emerges and is embedded in intermediate areas inside the security paper. The dewatering screen comprises a carrier screen which is provided in an area with an injection-molded insert, which has a relief with upwardly extending from a base body and the surface of the support screen protruding motif elements, which are formed in the form of window portions of the window security thread. In this case, the motif elements comprise at least one group of a plurality of micromotif elements juxtaposed transversely to the running direction of the thread to be embedded in order to produce microfine stars.

The invention further includes a dewatering screen of the type mentioned above, wherein the dewatering screen comprises a carrier screen which has a screen embossment in a partial area which has a relief with motif elements projecting beyond the surface of the carrier screen, which are formed in the form of the window areas of the window security thread. In this case, the motif elements comprise at least one group of a plurality of micromotif elements juxtaposed transversely to the running direction of the thread to be embedded in order to produce microfine stars.

In advantageous variants of the invention, the micromotif elements have a width transversely to the running direction of the thread to be embedded which is less than 50% of the thread width and lies between 0.2 mm and 4 mm.

In both designs of the dewatering screen, the motif elements preferably comprise micromotif elements whose outlines represent patterns, characters or a coding, in particular a letter or number sequence. Alternatively or additionally, the motif elements comprise a plurality of Micromotif elements whose spatial arrangement forms a motif, in particular letters, characters or figures.

In an advantageous development of the invention, the injection molding insert or the screen embossing has, in addition to the motif elements for producing the window regions of the window security thread, a watermark relief in the form of a watermark to be produced in the security paper. In particular, the watermark relief can supplement, continue or repeat in the same or modified form a motif formed by the outline or the arrangement of the micromotif elements.

For drainage screens with injection molding this is expediently formed from a hydrophobic plastic, such as polyoxymethylene. To reduce wear during operation, the plastic may be added with wear-reducing additives.

The injection-molded insert is preferably arranged in a cut-out region of the carrier screen and connected thereto only in a preferably serrated edge region. For this purpose, for example by means of a laser cutting device at the location of the screen mesh, on which the injection molding insert is provided, a recess can be produced which is slightly smaller, for example 1/10 mm smaller than the desired shape of the injection molding insert. The edge region can be designed in particular in the form of a pattern, preferably in a serrated form. In this cut-out portion of the injection molding insert can be inserted or preferably injected.

The carrier screen advantageously contains a screen fabric with at least one system of interwoven, longitudinally extending warp threads and weft threads extending transversely thereto, wherein the screen fabric advantageously contains either a metal fabric, in particular a bronze fabric, a metal-plastic mixed fabric, in particular a bronze-plastic mixed fabric, or a pure plastic fabric.

Furthermore, the injection molding insert preferably has a plurality of perforations, which ensure drainage during papermaking. The dimensions of these drainage perforations are chosen so small that they do not adhere to fibers during papermaking. Typical perforation diameters are between 100 μm and a few 100 μm, for example about 500 μm. In advantageous embodiments, the perforations taper towards the uppermost design surface of the injection molding insert or the perforations are formed waisted.

To produce an injection molding insert with an injection-molded relief of the type described above, an injection molding tool can be used which contains an injection molding cavity into which plastic can be injected to produce the injection molding insert and which is provided with a multi-stage tool relief in the form of the inverted injection molding relief. The injection molding tool including the injection molding cavity and the high-resolution multi-stage tool relief can be formed by milling or by an additive manufacturing process as a layer sequence of a plurality of firmly interconnected material layers.

To produce a screen embossing of the type described above, an embossing stick can be used which is provided with a high-resolution multi-level relief in the form of the inverted screen embossing. The embossing stick including the high-resolution multi-level relief can be made by milling or be formed by an additive manufacturing process as a layer sequence of a plurality of firmly interconnected material layers.

In particular, selective laser sintering, selective laser melting, electron beam melting, 3D printing with powder, melt stratification, laser deposition welding, multi-jet modeling, a polyjet process, stereolithography, laminated object modeling, film transfer imaging or digital light processing are considered as additive manufacturing processes.

Further details on the structure, properties and production of the injection molding tool or die can be found in the application DE 10 2014 008 752.2 are removed, the disclosure content of which is included in the present application in this respect.

Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation true to scale and proportion has been dispensed with in order to increase the clarity.

Fig. 1

eine schematische Darstellung einer Banknote mit einem erfindungsgemäßen Sicherheitselement in Form eines Fenstersicherheitsfadens,

Fig. 2

eine Detaildarstellung von Fensterbereichen mit Mikrofenstern einer erfindungsgemäßen Banknote in Aufsicht,

Fig. 3

eine Schemazeichnung zur genaueren Beschreibung des Versatzes der Mikrofenster einer Gruppe,

Fig. 4 bis 6

Detaildarstellungen von Fensterbereichen mit Mikrofenstern nach weiteren Ausführungsbeispielen der Erfindung in Aufsicht,

Fig. 7 und 8

jeweils eine schematische Darstellung eines erfindungsgemäßen Entwässerungssiebs, das zur Erzeugung von Mikrofenstern eingesetzt wird,

Fig. 9

Aufsichten auf eine Banknote mit einer Mehrzahl von Mikrofenstern, die in Ensembles von Mikrofenstern in Form eines Eurosymbols angeordnet sind, wobei (a) ein einzelnes Ensemble von Mikrofenstern und (b) mehrere, in Fadenlängsrichtung beabstandet und in Fadenquerrichtung gegeneinander versetzt angeordnete Ensembles von Mikrofenstern zeigt, und

Fig. 10

eine Gestaltung, bei der das Design einer Reihe papiermacherisch hergestellter Mikrofenster außerhalb des Sicherheitsfadens von einem Druckmuster fortgesetzt wird.

Show it:

Fig. 1

a schematic representation of a banknote with a security element according to the invention in the form of a window security thread,

Fig. 2

a detailed representation of window areas with micro-star of a bill according to the invention in supervision,

Fig. 3

a schematic drawing for a more detailed description of the offset of the micro-windows of a group,

4 to 6

Detailed representations of window areas with micro star according to further embodiments of the invention in supervision,

FIGS. 7 and 8

each a schematic representation of a dewatering screen according to the invention, which is used for the production of micro-windows,

Fig. 9

Top views of a banknote with a plurality of microfibers, which are arranged in ensembles of microsymbols in the form of a euro symbol, where (a) a single ensemble of micro-star and (b) shows multiple, spaced in the thread longitudinal direction and offset in the thread transverse direction staggered ensembles of micro-star , and

Fig. 10

a design in which the design of a series of papermaking-made micro-windows outside the security thread continues from a print pattern.

The invention will now be explained using the example of window security threads for banknotes and other value documents. Fig. 1 shows a schematic representation of a banknote 10 with a paper substrate 12, which is provided with a window security thread 14 according to the invention. The window security thread 14 has a thread length direction L extending in the longitudinal direction and a thread transverse direction Q perpendicular thereto, and protrudes in window areas 16 on the surface of the banknote 10, while FIG it is embedded in intermediate web areas 18 in the interior of the banknote 10.

In the presentation of the Fig. 1 all window areas 16 of the window security thread 14 are shown schematically as rectangles. As in the detailed representation of the Fig. 2 shown, the window portions 16 according to the invention include papermaking generated microfine window 20, which are formed in the embodiment in the form of small stars with irregular deckle edge 22. The width b _{M of} the micro window 20 lies with b _M = 1 mm significantly below the width of the dashed security thread 14, which in the embodiment b _F = 4 mm.

When viewed from above, the micro-windows 20 reveal the view of the window security thread 14 embedded in the paper, so that the security features arranged on the window security thread 14, for example a diffraction structure or a color-shifting layer, become visible there. In the web areas 18 between the window areas 16, the window security thread 14 is covered by the paper layer 12 and therefore the security features arranged thereon are not visible.

Since the microfibers 20 were produced in papermaking as described below, they have an edge 22 with characteristic irregularities, which is often referred to as deckle edge in this specification. The irregular edge structure arises from an irregular accumulation of fibers in the edge region and by protruding into the hole of individual fibers.

As in Fig. 2 2, the window areas comprise a plurality of groups of microfibers, each of which has a plurality of adjacent side-by-side yarns Include microphone windows 20. As explained above, the juxtaposition of micro-starlets in the transverse direction means more precisely that there is a straight line g in the yarn transverse direction Q which intersects all the group 30 micro-windows. For one of the three in Fig. 2 shown groups is such a straight line g drawn.

In this case, the micro-windows of a group 30 can all be at the same level, but are preferably as in FIG Fig. 2 , the micro-window 20 of a group 30 against each other in the yarn longitudinal direction L and thus are indeed next to each other, but not at the same height.

For a more detailed description of the offset of the micro window shows Fig. 3 two microphone windows 20-i, 20-j of a group 30 of transverse in the transverse direction Q adjacent micro-star and a straight line g, which intersects all the group 30 micro-windows. The height hi of a micro window 20-i is the dimension of the micro window in the longitudinal direction L. For each micro window 20-i, a center line 24-i can be specified, which halves the extension of the micro window in the longitudinal direction L and lies parallel to the line g. The offset di of a micro-window 20-i is then the signed distance of the centerline 24-i of this micro-window from the line g, as in FIG Fig. 3 shown. For the treatment of differently sized microphone windows 20 in a group 30, the dimensionless reduced offset δ _i = di / hi is expediently introduced.

Since the line g intersects all the microphone windows 20-i, the relationship | di | ≤ 0.5 * h _i , the amount of the offset is thus at most as large as half the height of the microphone window. In other words, the reduced offset of the micro-windows of a group is at most 0.5, ie | δ _i | ≤ 0.5, for i = 1, 2, .... N.

A stronger togetherness impression of a group arises when the micro-windows of the group have a smaller maximum reduced distance δ _max from the straight line g, ie | δ _i | ≤ δ _max , for i = 1, 2, .... N, with 5 _max <0.5. In particular, values of δ _max between 0.2 and 0.4 have proven to be advantageous.

In the case of several micro-windows 20-i in a group, it is also advantageous if the various adjacent micro-windows 20-i have as different a reduced offset as possible, since then the available offset latitude under the boundary condition of a juxtaposed position is optimally utilized.

For example, N micro-windows, which should have a maximum reduced distance δ _max from the straight line g, advantageously have a minimum offset of at least δ _max / (N-1) from one another, ie, it holds true $$\left|{\mathrm{\delta }}_{\mathrm{i}}-{\mathrm{\delta }}_{\mathrm{j}}\right|\ge {\mathrm{\delta }}_{\mathrm{Max}}/\left(\mathrm{N}-1\right)\mathrm{for\; all\; couples\; i}.\mathrm{j\; with\; i}\ne \mathrm{j},$$

mit 1 ≤ k ≤ 2.As one skilled in the art will appreciate, the maximum mutual minimum offset for N micro-star is 2δ _max / (N-1), which is twice as great as the above-mentioned advantageous minimum offset. The offset values of the microphone windows can therefore also be set to sharper conditions, ie $$\left|{\mathrm{\delta }}_{\mathrm{i}}-{\mathrm{\delta }}_{\mathrm{j}}\right|\ge \mathrm{k}*{\mathrm{\delta }}_{\mathrm{Max}}/\left(\mathrm{N}-1\right)\mathrm{for\; all\; couples\; i}.\mathrm{j\; with\; i}\ne \mathrm{j}$$

with 1 ≤ k ≤ 2.

In a specific embodiment with N = 5 micro-windows and a maximum reduced offset of δ _max = 0.3, the individual micro-windows can be used, for example, with reduced offset values of 0.3, 0.15, 0, -0.15 and -0.3 are arranged and then have against each other the maximum possible minimum offset of 2δ _max / (N-1) = 0.15. In this case, in the above condition, the sharpest case k = 2 is realized.

If a somewhat more irregular distribution of the offset values is to be achieved, the mutual minimum offset must be reduced, but is advantageously still greater than δ _max / (N-1). For example, the mutual minimum offset of 0.15 can be reduced to a value of 0.1 (k = 1.33 in the above condition). The individual micro-windows can then be arranged approximately with reduced offset values of 0.25, 0.15, 0, -0.12, and -0.3 and then have an irregular distributed mutual offset, which, however, is at least 0.1.

In the embodiment of Fig. 2 N = 3 and δ _max = 0.25. The micro-windows 20 of the groups 30 are arranged with the reduced offset values 0.25, 0 and -0.25, ie they have the maximum possible minimum offset of 2δ _max / (N-1) = 0.25.

Fig. 4 shows a further embodiment of the invention, in which the groups 30 each contain nine or ten microphone windows 20 which are arranged regularly and at the same height in rows of three. For one of the groups 30, a straight line g is drawn, which intersects all the microphone windows 20 of the group. The micro-windows 20 are formed in this embodiment in the form of small circular disks with a diameter of only 0.2 mm. Even if the individual micro-windows 20 are very small, the totality of the micro-windows of the groups 30 nevertheless allows a clear view of the window-security thread 14 embedded in the paper, so that its security features can appear.

Another very decorative embodiment is in Fig. 5 shown. The micro windows 26, 28 of the group 30 are formed in the form of partially cut wavy lines. Unlike the embodiments shown so far, the micro windows 26, 28 of the group 30 have neither all the same shape nor the same size. The drawn line g intersects six microphone windows 26, 28, so that these micro windows are thus juxtaposed in the sense of this description and form a group of 30 adjacent microphone windows. The upper and lower triangular microphone windows 26 are not adjacent to each other, since there is no straight line in the cross-thread direction that would cut all these micro windows. However, the upper triangular micro-windows together with the wavy micro-star 28 form a group of adjacent microphone windows. It is thus also possible that some micro-windows, such as the micro-windows 28, belong to more than one group of adjacent micro-windows.

While the triangular micro window 26 has a width that is significantly smaller than the thread width (b ₂₆ ≈ 0.1 b _F ), the wavy micro window 28 occupy almost the entire thread width (b ₂₈ ≈ 0.9 b _F ). Also in this embodiment, the micro-windows 26, 28 release the view of the embedded in the paper window security thread 14 and allow its security features to appear.

In the further embodiment of the Fig. 6 the paper-made microfine windows 20 are each formed in the form of a motif, namely in the form of adjacent in the thread transverse direction digits "1" and "5", which together form the number sequence "15". Also in this embodiment, the width b _{M of} the micro window 20 is significantly smaller than the thread width b _F , which is for example 4 mm, and is in the embodiment at only about 1 mm (25% of the thread width, number "1") or 1.5 mm (37.5% of the thread width, number "5"). The height h _{M of} the micro window 20, so the extension in the yarn longitudinal direction L is about 2 mm and is therefore also substantially smaller than the window areas in conventional window filaments.

It is understood that the banknote 10 can also have conventional window areas in addition to window areas with the described micro-windows 20. However, since these are known, will not be discussed in detail in the present application.

To make designs, such as those related to the FIGS. 2 to 6 described micro-windows 20, 26, 28, to produce in the region of a window security thread 14, according to the invention in Fig. 7 used schematically in a section transverse to the direction of yarn advancing drainage 60.

The dewatering screen 60 comprises a carrier screen 62 with a screen mesh 64, which is cut out in a subregion 40. The screen fabric 64 has at least one system of interwoven longitudinally extending warp yarns 66 and weft yarns 68 extending transversely thereto. In the context of the present invention, the screen fabric may for example contain a metal fabric, in particular a bronze fabric, a metal-plastic mixed fabric, in particular a bronze-plastic mixed fabric, or even a pure plastic fabric. The support screen 62 can contain both a single-layer and a multi-layer screen fabric, with only a single-layer screen fabric being shown in the figure for the sake of simplicity.

In the cut-out portion 40 of the mesh fabric 64, a plastic injection-molded insert 50 is arranged, which is connected at its edge to the mesh 64. The connection can in principle be made in many ways, for example by a plastic encapsulation or back injection, with the aid of a plurality along the edge arranged fastening knobs, or by welding or gluing. In the embodiment, a presently preferred variant is realized in which the injection molding insert 50 is injected with a corresponding tool shape directly into the cut-out portion 40 of the mesh fabric 64 and thereby enters into a particularly intimate connection with the mesh.

The injection-molded insert 50 has a relief 52 in the form of the window areas 16 of the window security thread 14 and contains a base body 54, from which starting motif elements in the form of the window areas 16 extend upwards and project beyond the screen surface. It is essential for the present invention that the motif elements contain small micromotif elements 56, which are formed in the shape and size of the microfibrils 20 and extend upwards with a sharp edge. In the exemplary embodiment, the relief 52 is produced by means of milling, so that the flanks 57 of the small micromotif elements 56 enclose an angle of approximately 15 ° with the surface normal.

In papermaking in a rotary screen paper machine, the security thread 14 to be embedded is fed as an endless element from a bobbin via a deflection roller to the dewatering screen 60 with the injection molding insert 50. During immersion of the injection molding insert 50 into the paper pulp, the security thread 14 rests on the motif elements and in particular also on the micromotif elements 56 of the injection molding insert 50.

Since a negative pressure prevails in the interior of the dewatering screen 60, the water of the water-fiber dispersion of the pulp is sucked into the interior of the dewatering screen. In the process, the fibers deposit on the surface of the dewatering screen 30 and the injection-molded insert 50 and form the desired paper web. At the points where the security thread 14 rests on the motif elements or the micromotif elements 56, the security thread is sucked by the negative pressure to the dewatering screen, so that there can accumulate no fiber mass. Accordingly, the security thread 14 remains free of fiber mass in the areas of the motif elements or the micromotif elements 56, while paper fibers accumulate in the surrounding areas and embed the security thread 14 in the paper. The motif elements or the micromotif elements 56 therefore generate just the desired window areas or microfine windows 20 in the forming paper layer.

Because of the papermaking of the micro-windows 20, the edge region 22 of the micro-windows is not completely sharp, as in the case of subsequent production of holes by means of punching or laser cutting. Rather, 20 fibers are deposited in the edge region of the micro-window, which project into the opening in an irregular manner and thereby produce the characteristic deckle edge.

The extent of edge sharpness or edge blurring of the microfine window 20 can be predetermined by the three-dimensional shape of the micromotif elements 56. Micromotif elements such as the micromotif elements 56 of the Fig. 7 , which have very steep flanks 57 and a small edge width, produce edge regions 22 with little irregularity, while micromotif elements with flatter flanks and larger edge width, such as those in Figs Fig. 8 shown micromotif elements 58, micro-windows 20 with highly irregular edge regions 22 produce.

The edge width of a micromotif element is the width within which the height of a micromotif element falls from 90% of the maximum height to 10%. Micro-windows with only slightly irregular marginal areas can be created with micromotif elements 56 having a marginal width of 0.6 mm or less, 0.5 mm or less, or even 0.4 mm or less. On the other hand, micromotif elements 58 with a marginal width of more than 0.6 mm, more than 1 mm or even more than 1.5 mm can produce microfibres with strongly irregular marginal regions 22.

The injection molding insert 50 is further provided with a plurality of perforations 48 to ensure dewatering in papermaking also in the field of injection molding. The diameter of the perforations 48 is chosen so small that they do not adhere to fibers in papermaking. Typical perforation diameters are between 100 μm and a few 100 μm, for example about 500 μm.

FIGS. 9 and 10 show further advantageous embodiments of inventive micro windows in banknotes or other data carriers. In the embodiment of Fig. 9 (a) For example, the micro-windows 20 are formed in the form of ovals having a dimension of 0.4 mm x 0.3 mm. In each case, a plurality of oval micro-star 20 forms an ensemble 70, the micro-windows 20 are arranged spatially to each other so that they form together as a motif the euro symbol "€". As in Fig. 9 (a) further shown, the ensemble 70 includes a plurality of groups 30 of adjacent micro-star 20, wherein in each group, the micro-windows 20 are offset in the yarn longitudinal direction L against each other. Specifically, the ensemble 70 contains four groups 30, which consist of 2 or 3 micro-windows and for which the associated intersecting lines g are shown for illustration.

As in the embodiments described above, the micro-windows 20 of the ensemble 70 reveal the view of the window security thread 14 embedded in the paper and allow the security features arranged thereon to be visible.

In the embodiment of Fig. 9 (b) are several ensembles 70 of micro-star 20, each in the form of the euro symbol €, arranged in the thread longitudinal direction L spaced. The ensembles 70 are offset as a whole in the transverse direction Q against each other slightly to compensate for variations in the introduction of the security thread 14 into the paper, for example due to wobbling. If Δ denotes the maximum distance by which a security thread 14 can be introduced into the security paper 12 in the transverse direction Q due to wobbling, it can be ensured by offsetting the Eurosymbol ensembles 70 up to a distance Δ to the right and left longitudinally always some complete symbol ensembles 70 lie directly above the security thread 14 and form the desired micro-windows in the form of the euro symbol.

The design of the microphone windows need not be limited to the security thread 14, but may also continue laterally beyond, for example in the form of a watermark or by another security feature. For illustration shows Fig. 10 a design in which a plurality of papermaker's fabricated micro-windows 80 is disposed over a window security thread 14 and, as described above, exposes the security features of the embedded window security thread 14.

As in Fig. 10 illustrated, the circular disk-shaped micro-windows 80 contain a plurality of groups of transverse in the transverse direction Q adjacent micro-star. In addition, the micro windows 80 have different sizes, but are all significantly smaller than the thread width.

The design formed by the micro-starlets 80 is continued outside the security thread 14 by a printed pattern 82 in the form of a printed cloud of points and thereby integrated into the overall design of the banknote 10. This also significantly increases the counterfeit security of the banknote since the security thread 14 can not be replaced by a security thread without a microfine window 80 and, in addition, since the security thread 14 must be aligned correctly with the print pattern 82 in the longitudinal direction.

Instead of a printing layer, a motif formed by the outline or arrangement of the micro-windows can also be continued, for example, by a watermark. The micro windows, which in any case represent thin areas in the paper layer of a data carrier, are preferably part of a watermark which protrudes laterally beyond the window security thread.

LIST OF REFERENCE NUMBERS

10

bill

12

paper substrate

14

Windowed security thread

16

panes

18

web regions

20, 20-i, 20-j

micro window

22

Edge with characteristic irregularities

24-i

center line

26.28

micro window

30

Groups of micro star

40

cut out section

48

perforations

50

Watermark use

52

relief

54

body

56, 58

Micromotif elements

57

flanks

60

dewatering

62

support screen

64

mesh

66

warp

68

wefts

70

ensemble

80

micro window

82

print pattern

G

Just

L

Thread longitudinal direction

Q

Thread transversely

Claims (19)

1. A data carrier (10), especially a value or security document, having a substrate (12) that comprises at least one paper layer, there being embedded in the substrate a window security thread (14), having an elongated thread longitudinal direction and a thread transverse direction perpendicular thereto, that is visible on at least one surface of the substrate in certain window regions (16), the window regions comprising at least one group (30) of multiple micro windows (20) that lie next to one another in the thread transverse direction, characterized in that the micro windows are produced with papermaking technology and comprise an edge (22), produced at paper manufacture, having characteristic irregularities.
2. The data carrier according to claim 1, characterized in that the window regions comprise at least one group having three or more, preferably five or more micro windows that lie next to one another in the thread transverse direction.
3. The data carrier according to claim 1 or 2, characterized in that, in at least one group of micro windows that lie next to one another, the micro windows are offset against one another along the thread longitudinal direction in such a way that they do not lie on the same level, but in that there is a straight line in the thread transverse direction that intersects all micro windows in the group.
4. The data carrier according to claim 3, characterized in that the group includes N micro windows, where N ≥ 2, and each micro window has a height hi and an offset di from a straight line that intersects all micro windows, where i = 1, 2, ... N, and for each micro window, the reduced offset δ_i = d_i/h_i being smaller, in terms of absolute value, than a maximum spacing value δ_max, which is less than 0.5 and is preferably between 0.2 and 0.4.
5. The data carrier according to claim 4, characterized in that the micro windows have a minimum offset against one another of δ_max/ (N-1), in other words in that $$\left|{\mathrm{\delta }}_{\mathrm{i}}-{\mathrm{\delta }}_{\mathrm{j}}\right|\ge {\mathrm{\delta }}_{\max }/\left(\mathrm{N}-1\right)\mathrm{is\; true\; of\; all\; pairs\; i},\mathrm{j\; where\; i}\ne \mathrm{j.}$$

   
6. The data carrier according to at least one of claims 1 to 5, characterized in that the width of the micro windows of the at least one group in the thread transverse direction is, in each case, less than 50%, preferably less than 40%, particularly preferably less than 30% of the thread width.
7. The data carrier according to at least one of claims 1 to 6, characterized in that, in the at least one group, the length of the micro windows parallel to the thread longitudinal direction is between 0.2 mm and 4 mm, preferably between 0.3 mm and 3 mm and particularly preferably between 0.5 mm and 1 mm, and/ or the width of the micro windows in the thread transverse direction is between 0.2 mm and 4 mm, preferably between 0.3 mm and 3 mm and particularly preferably between 0.5 mm and 1 mm.
8. The data carrier according to at least one of claims 1 to 7, characterized in that the at least one group comprises micro windows whose contours constitute patterns, characters or a code, especially a letter or number string.
9. The data carrier according to at least one of claims 1 to 8, characterized in that the window regions comprise a plurality of micro windows whose spatial arrangement forms a motif, especially letters, characters or figures, preferably in that the plurality of micro windows comprises at least one of the groups of micro windows that lie next to one another.
10. The data carrier according to at least one of claims 1 to 9, characterized in that the micro windows, as thin sites in the paper layer of the substrate, are part of a watermark that protrudes laterally over the window security thread.
11. The data carrier according to at least one of claims 1 to 10, characterized in that a motif formed by the contour or the arrangement of the micro windows is continued beyond the window security thread by another security feature.
12. The data carrier according to at least one of claims 1 to 11, characterized in that the window security thread is provided with diffraction patterns, liquid crystal layers, thin-film structures, gaps in opaque, especially metallic layers, fluorescent substances, magnetic, conductive and/ or metallic layers.
13. A dewatering screen for manufacturing security paper having a window security thread that, after its embedding, is visible on at least one surface of the security paper in certain window regions, the dewatering screen comprising a carrier mold that is provided in a sub-region with an injection molded insert that comprises a relief having motif elements that extend upward from a base body and overtop the surface of the carrier mold and that are developed in the form of the window regions of the window security thread, and the motif elements for producing micro windows comprising at least one group of multiple micro motif elements that lie next to one another transverse to the running direction of the thread to be embedded.
14. A dewatering screen for manufacturing security paper having a window security thread that, after its embedding, is visible on at least one surface of the security paper in certain window regions, the dewatering screen comprising a carrier mold that in a sub-region comprises a mold embossing that comprises a relief having motif elements that overtop the surface of the carrier mold and that are developed in the form of the window regions of the window security thread, and the motif elements for producing micro windows comprising at least one group of multiple micro motif elements that lie next to one another transverse to the running direction of the thread to be embedded.
15. The dewatering screen according to claim 13 or 14, characterized in that the micro motif elements transverse to the running direction of the thread to be embedded have a width that is less than 50% of the thread width and is between 0.2 mm and 4 mm.
16. The dewatering screen according to one of claims 13 to 15, characterized in that the motif elements comprise micro motif elements whose contours constitute patterns, characters or a code, especially a letter or number string, and/ or in that the motif elements comprise a plurality of micro motif elements whose spatial arrangement forms a motif, especially letters, characters or figures.
17. The dewatering screen according to at least one of claims 13 to 16, characterized in that the injection molded insert or the mold embossing comprises, besides the motif elements for producing the window regions of the window security thread, a watermark relief in the form of a watermark to be produced in the security paper.
18. The dewatering screen according to at least one of claims 13, 15 to 17, characterized in that the injection molded insert is arranged in a cut-out region of the carrier mold and is joined therewith only in a preferably serrated edge region.
19. The dewatering screen according to at least one of claims 13, 15 to 18, characterized in that the injection molded insert comprises a plurality of perforations whose dimensions are so small that no fibers stick in them at paper manufacture.

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