EP0625431A1 - Security paper - Google Patents

Abstract

A description is given of a security paper (15) having an embedded security thread (7), which is embedded in the paper in such a way that it is freely accessible in some regions. The security thread (7) has a width which is greater than 2 mm. The security paper (15) consists of at least two layers of paper (6, 9), which are produced on separate paper systems. The security thread (7) is embedded in the first layer of paper (6), which has openings (16) or recesses in its surface, through which the thread is partially accessible on both sides. This first layer of paper (6) is covered with at least one second layer of paper (9) and joined firmly to the latter, the second layer of paper (9) having a thickness of 10 to 50%, preferably 20%, of the total thickness of the security paper (15). By means of the use of particularly wide security threads and the associated possibility of providing the threads with specific optical effects, the security against falsification of the security paper (15) equipped therewith can be improved. <IMAGE>

Description

The invention relates to a security paper with an embedded security tape, which is embedded in the paper such that it is at least partially freely accessible, and a method for its production.

For security papers such as banknotes, securities, documents, identity cards, etc., it is known to store security elements in the form of threads, tapes or the like as a security feature. These threads or tapes are usually introduced into the paper during the manufacture of the paper. In the case of circular sieve systems, the thread or the band is introduced into the pulp and brought up to the sieve in such a way that it is embedded in the fiber structure during sheet formation. This storage method is well known and e.g. B. in EP-A1 0 279 880 (Crane) or EP-A1 0 452 407 (GAO).

Sometimes it is desirable that the security element is embedded in the security paper so that it is exposed at least at one point on the surface of the security paper. If the security element has optically variable effects, its effect is considerably increased by the at least partial exposure of the security element, or in many cases becomes effective at all.

One possibility of introducing such a so-called window security thread into a document is known from EP-A1 0 059 056 (portals). The security element is brought outside the pulp to the paper sieve in such a way that it protrudes on raised areas, called humps in the following text comes to lie. At the points where the security thread rests on the humps, no paper can form on the side facing the sieve, so that it is freely accessible precisely at these points in the paper which will be produced later.

It is known that the incorporation of a security thread presents difficulties in practice insofar as the formation of sheets above and below the thread is hindered, since in the area of the thread the flow velocity of the pulp in the direction of the sieve is significantly changed or reduced. The wider the thread to be stored, the more this affects. In order to ensure a sufficiently good sheet quality, the method known from EP-OS 0 059 056 is therefore limited to threads whose width does not exceed 1 mm - 1.5 mm.

In order to also enable the embedding of wide security bands, it is proposed in EP-PS 0 070 172 (portals) to embed the thread according to the classic technique described at the beginning (sieve without hump), but to make special demands on the thread material to be embedded. The film-like security tape is designed to be liquid-permeable in certain, periodically repeating partial areas, so that fiber deposition or sheet formation is still possible in these areas during paper production, but sheet formation is prevented in the impermeable areas. During the embedding of such a security tape, areas are formed in the area of the liquid-impermeable zones in which the tape is freely accessible on one side.

Although this process can also be used to store very wide tapes in the paper and make them accessible in window areas, it proves to be disadvantageous that the homogeneity of the tape is interrupted again and again by the periodically provided perforations in the longitudinal direction. As a result, a particular advantage of previous window security threads is lost, which consists in the fact that the optical effects of the tape (negative writing, optically variable properties, etc.) can only be checked in the window areas in incident light, but the areas embedded in the paper can also be recognized in transmitted light . If the security thread or security tape is applied homogeneously in the longitudinal direction, it can be recognized as a continuous bar in transmitted light and is therefore easy to check. If it has inhomogeneities in the areas embedded in the paper, it does not differ very much when viewed from reflected light / transmitted light and is therefore difficult to distinguish from imitations applied.

The object of the invention is now to propose a security document in which a wide window security band is embedded, the security band in the document having a uniform appearance in reflected and transmitted light and a method for its production.

This object is achieved by the features specified in the characterizing part of claim 1. The inventive method aspects can be found in the characterizing parts of claims 9 and 10.

The basic idea of the invention is that a security paper with window security thread is formed in a known manner, in which the security thread is deliberately made so wide that inevitably a paper is formed which has defects in the area of the security thread or security tape in the form of arbitrary holes . Usually tried the expert to avoid such defects in any case. In the security paper according to the invention, these imperfections are consciously accepted in order to subsequently combine or connect them with one or two flawless paper layers in such a way that all imperfections are covered by the additional layer (s) or brought into a defined form.

The invention is based on the surprising finding that, in the production of security papers with window security threads, the introduction of threads that are getting wider and wider from a certain width of the strip first on the side facing away from the screen (rear side) above the safety strip has defects in the form of Holes arise. As the width of the belt increases, the number and size of these imperfections increase, but without the same errors also occurring on the side of the paper facing the screen (front side). Only after increasing the width further do these errors appear on both sides at the same time. If the width of the security band is increased further, in the extreme case in the area of the security band the sheet formation on both sides of the security band is completely avoided.

If one ascertains experimentally from which width of the security band the errors on the back and from which width they also occur on the front, one has the two limit values in which, in the simplest case, one can move when selecting the security bands which can be used according to the invention.

Experience has shown that the first defects appear on the back from a width of about 1.5 - 2 mm. Without additional measures on the rotary screen system, you can now use the usual mesh size of the screen (approx. ... millimeters) and the usual height of the humps (approx. ... millimeters) increase the width of the security tape to about 4 - 5 mm before defects also appear on the front of the paper.

With the solution according to the invention, it is now possible for the first time to use security threads on the circular sieve installation without any special measures, which instead of the previous 0.75-1 mm width can now have a width of up to approx. 4 mm. By increasing the mesh size of the screen (which is only possible within narrow limits if the fiber length remains unchanged) and changing the height and shape of the bumps, further increases in width are possible without errors occurring on the front of the paper.

If even wider security tapes are to be used, it is proposed according to a development of the invention to additionally provide liquid-permeable areas in the edge area of the security tape that are not visible in the finished paper. With this measure, even when the impermeable band area is completely exposed, the band can still be embedded and anchored to the edge area. These measures now even give the possibility of storing security tapes of any width in the first paper layer so that, in extreme cases, they are continuously accessible from both sides in the central area of the security tape.

If the liquid-permeable edge regions are provided on both sides along the security band and are made sufficiently wide, the security band is anchored so intensely in the paper layers arranged on both sides that the paper web can only be detached from the finished paper with great mechanical force Load is possible. Such security paper can therefore in principle also be used without additionally applied paper layers. By applying additional layers of paper, the security paper can also be stabilized and its appearance changed further. The second paper layer can also have window areas in the area of the security band, in which the security band is then accessible unchanged.

By applying additional paper layers on one or both sides with or without window areas, security paper variants can be produced that differ very clearly from previous ones. The particularly wide security tapes give security papers a specific appearance that clearly distinguishes them from others and that cannot be reproduced with modern copiers.

The security paper according to the invention has the further advantage that the use of substantially wider security tapes, particularly when windows are used at the same time, makes them much easier to check simply because of the larger area. However, the larger area also allows the use of more complex and complicated printed images and optical effects, so that it is also more difficult to imitate such security tapes. Since security papers of this type can also be produced on conventional twin-wall paper machines, the method according to the invention can be used without major additional production-related expenditure or investments. When using special security threads that are permeable in the edge area, there are also completely new possibilities in the design of the security papers, since now also on very easily accessible security tapes can be integrated into the security paper on one or both sides over the entire length. If necessary, the accessibility of these tapes can also be prevented on one or both sides by combination with one or two further layers of paper, which can also have congruent or mutually offset windows. Due to the special arrangement of such tapes in the multi-use paper web or by cutting the web / sheets in the area of the tape, even security papers can now be produced which consist of transparent film material on one edge and only pass into the known fiber paper at a certain edge distance.

Further advantages and advantageous developments are the subject of the dependent claims and the content of the description of the invention with reference to the figure.

Fig. 1

die schematische Darstellung einer Doppelrundsieb-Papiermaschine zur Herstellung eines Sicherheitspapiers;

Fig. 2

eine Detaildarstellung des Rundsiebs mit Höckern zur Erzeugung von Fensterbereichen in der Papierbahn;

Fig. 3 - 5

Draufsicht und Schnittdarstellungen eines Sicherheitspapiers mit Fenstersicherheitsfaden;

Fig. 6

die schematische Darstellung eines Sicherheitsbandes mit flüssigkeitsdurchlässigem Randbereich;

Fig. 7

eine Detaildarstellung des Rundsiebs mit ringförmiger Erhöhung

Fig. 8

die Rundsieberhöhung der Fig. 7 mit aufliegendem Sicherheitsband (Schnittdarstellung);

Fig. 9

Draufsicht auf ein Sicherheitspapier mit durchgehendem Fensterbereich;

Fig. 10, 11

Schnitte CD des Sicherheitspapiers der Fig. 9;

Fig. 12

Draufsicht auf ein Sicherheitspapier mit eingebettetem Sicherheitsband und unterschiedlichen Fenstervarianten;

Fig. 13

Schnitt EF des Sicherheitspapiers der Fig. 12;

Fig. 14

Draufsicht auf ein Sicherheitspapier mit transparentem Kantenbereich;

Fig. 15

Schnitt GH des Sicherheitspapiers der Fig. 14;

Fig. 1 zeigt die schematische Darstellung einer Doppelrundsieb-Papiermaschine wie sie zur Herstellung von Sicherheitspapier Verwendung findet. Die Anlage besteht aus zwei Rundsieb-Papiermaschinen 1 und 2, die über einen Abnahmefilz 3 miteinander verbunden sind.Show it:

Fig. 1

the schematic representation of a twin circular paper machine for the production of security paper;

Fig. 2

a detailed view of the circular screen with bumps for creating window areas in the paper web;

3 - 5

Top view and sectional views of a security paper with window security thread;

Fig. 6

the schematic representation of a security tape with liquid-permeable edge area;

Fig. 7

a detailed representation of the circular sieve with an annular increase

Fig. 8

the round screen elevation of Figure 7 with overlying security band (sectional view).

Fig. 9

Top view of a security paper with a continuous window area;

10, 11

Sections CD of the security paper of Fig. 9;

Fig. 12

Top view of a security paper with an embedded security tape and different window variants;

Fig. 13

Section EF of the security paper of Fig. 12;

Fig. 14

Top view of a security paper with a transparent edge area;

Fig. 15

Section GH of the security paper of Fig. 14;

Fig. 1 shows the schematic representation of a twin circular paper machine as used for the production of security paper. The system consists of two circular screen paper machines 1 and 2, which are connected to one another via a take-off felt 3.

In the paper machine 1, a paper web 6 is formed on the circular wire 4, in which a security band 7 is embedded. The security band 7 runs onto the hump 5 of the rotary screen 4 before the assigned one Bump 5 or the respective screen area is immersed in the pulp 8 of the paper machine. In the paper web 6 produced in this way, the security band is located in an inner plane of the paper. In the areas where it rests on the humps, however, the security band 7 is freely accessible. The production of such paper webs 6 corresponds to the manufacturing process as described, for example, in EP-PS 056 059.

Using the paper machine 2, a second paper web 9 is produced parallel to the production of the paper web 6, which in the present example is homogeneous, i. H. without windows or the like. The paper web 9 is removed from the circular wire 11 by means of the so-called take-off felt 10, connected to the paper web 6 in the area of the pressure roller 12 and, together with this, fed to the further processing stations (calenders, paper sizing, etc.) of the production plant.

Fig. 2 shows a detail of the circular screen system 1, in which the described introduction of the security band 7 can be seen somewhat more clearly. In particular, it is shown that in the areas in which the safety band 7 rests on the hump 5, no sheet formation is possible, since no fibers can be deposited due to the intimate contact between the safety band 7 and the hump 5. On the finished paper, these contact areas form the window areas in which the security band will later be freely accessible. The bumps 5 in the sieve 4 are usually made much wider than the safety band. This enables the security tape to be inserted within a wide tolerance range. Depending on the shape of the bumps 5 and their arrangement with one another in the circumferential track of the circular sieve 4, the number and position of the Window areas can be planned specifically in later paper.

As mentioned at the beginning, the formation of sheets in the area of the security thread or security band depends on the width of the security band, since the band 7, which is usually impermeable to liquids, hinders dewatering through the sieve 4. It is known to the person skilled in the art that, if the security tapes are too wide, errors can occur in the form of holes which expose the security tape. Since the first errors are to be expected with a width of approximately 1.5 mm, security threads with a width of up to 1 mm are usually used.

More detailed studies have now shown that with an increase in the security thread width not on both sides of the security band, as expected. H. the side 13 facing the screen 4 and the side 14 facing away from the screen, errors in the form of holes occur at the same time. Surprisingly, the errors first appear on the back of the security band, i. H. occur in the layer area 14 of the paper web. Only after a significant increase in the security bandwidth is the sheet formation also influenced in the layer area 13 in such a way that random holes also occur in addition to the deliberately created window areas. If the width of the security band is increased further, the number and size of the holes on both sides of the paper web continue to increase until finally, in the area of the security band on both sides, sheet formation is completely prevented.

According to the invention, security tapes are now used in a first embodiment, the width of which is selected to be large enough to be on the back of the later security paper, ie in the area 14 of the security tape 7, defects occur in the form of holes, but such errors cannot yet be seen on the front, ie in area 13. Such security tapes preferably have a width of 2 mm - 4 mm.

If the faulty back of the security paper produced in this way is covered with the paper web 9 produced in the second rotary screen system, there is always a minimum paper thickness in the area of the imperfections, which gives a homogeneous impression of the paper surface. The errors in the paper web 6 are thus hidden from the later viewer.

Fig. 3 shows a security paper with embedded window security tape in plan view. It has window areas 16 and areas 17 in which the security paper is embedded in the paper or covered by fibers.

If one now assumes that the security paper shown in FIG. 3 is a paper produced according to a conventional method, in which a security tape with a width of 4 mm was “erroneously” embedded, this has, for example, a defect in area 18 which 4, similar to window area 16, exposes the security band.

5 shows the same section AB of the security paper, but with the stipulation that this security paper was produced by the method according to the invention. In this embodiment, the defect 18 is covered with the additional paper web 9. Paper web 6 and paper web 9 are shown differently hatched in FIG. 5, but no separate paper layers can be determined in the finished paper, since two paper webs merged shortly after the sheet formation in the following processing steps (calendering, gluing, drying, etc.) bond so intimately that a separation or differentiation of the individual webs is no longer possible. By superimposing these two layers, the impression of a paper web produced without errors is created.

FIG. 6 shows a special embodiment of a security band 19 which is designed to be substantially wider than the originally defined security band. This security band 19 is, for example, 20 mm or 30 mm wide. It has liquid-permeable and ideally even fiber-permeable regions in the edge regions 20. In the central region 21, the band 19 is made impermeable to liquids.

Such a security band 19 can be made, for example, from a film strip which has been made permeable to liquid or fiber in the edge region by perforation. Alternatively, however, a liquid or fiber-permeable fabric tape can also be used, which was made liquid-impermeable in the central region 21 by special impregnation or coating.

If such a security band 19, as shown in FIG. 7, runs onto an annular elevation 22 of the sieve 4, viewed in the direction of rotation of the sieve, and the annular elevation 22 is formed so narrow that the permeable edge regions 20 over the elevation 22 protrude (Fig. 8), the security band in the impermeable area 21, as far as this rests on the ring, will prevent sheet formation. In the protruding, permeable marginal areas 20 but it is embedded in the paper.

The result of this procedure is a security paper, in which an extremely wide security band is embedded, which is freely accessible from both sides in the central region 21. The edge regions 20 are firmly anchored in the paper due to the permeable structure. Such a paper is shown in FIGS. 9 and 10 in a top view and in a sectional view.

FIG. 11 shows the section of such security paper, in which one side is provided with an additional paper layer 9. This gives the security paper a homogeneous appearance on one side. On this page it is therefore possible to print over the entire area like conventional security papers.

On the other hand, the security paper is interrupted by the security tape 19. If the security band has holographic or other optically variable effects, it seems sensible to include these areas only in the transition area in the printed image. If the security band only has shiny metallic structures, each of which would be relatively easy to imitate, it is recommended that the security print image (steel gravure, guilloche pattern, etc.) also be provided over this area. In this way, the metallic sheen of the security tape is combined with the security print image or firmly connected to it.

In the embodiments shown in FIGS. 12 and 13, the security paper 23 is connected on both sides to a further paper layer 27, 28. Both outer paper layers 27, 28 have windows 16 in the area of the security band, which are relative to one another in this way are arranged so that the security band is accessible on both sides, once through a window only from the front and finally through another window only from the rear. A security paper produced in this way can be processed on both sides like normal security papers. In the relatively large window areas, all of the visually verifiable properties provided on the security band are very clearly accessible and can therefore be easily checked by anyone even without optical aids. The window, which is accessible from both sides, allows the provision of see-through features, e.g. B. in transmitted and reflected light varying layers of color, which further increase the security against forgery.

Finally, FIGS. 14 and 15 show a security paper in which the security tape is arranged in the edge area. As can be seen in particular from section GH, the security band 26 is only anchored in the paper on one side. The production of such security paper is possible, for example, by arranging the security paper 25 in the multi-use paper web to be manufactured in such a way that the cutting line for the individual banknote tracks runs in the middle of the security band. As an alternative to this, it is also conceivable to provide the security tape in the edge region of the cutting lines in the paper production in such a way that the area of the security tape projecting beyond the cutting edge is removed as a waste strip. Although this embodiment has the advantage that the width of the film area must be maintained more precisely, since the cutting lines can be oriented at the film / paper transition, the disadvantage, however, is the need for several cuts to be controlled by control mechanisms. In addition, this procedure decreases because of the unusable Stripes in the separated edge area, the usable area of the paper web.

It is clear to the person skilled in the art that the embodiments mentioned are exemplary and that, in addition, a large number of further embodiments are conceivable which are based on the basic idea of the invention.

Claims (17)

Security paper with an embedded security tape, which is embedded in the paper in such a way that it is at least partially freely accessible, characterized in that - The security band (7, 19) has a width greater than 2 mm, the security paper is made up of multiple layers, ie has at least two layers of paper which are produced on separate paper systems, - The security band (7, 19) is embedded in the first paper layer (6) and is at least partially accessible on both sides through openings in the paper surface and that - The first paper layer (6) is covered with at least one second paper layer (9) and is firmly connected thereto, the second paper layer (9) having a thickness of 10-50%, preferably 20%, of the total thickness of the security paper (15, 23 , 25). Security paper with an embedded security tape, which is embedded in the paper in such a way that it is at least partially freely accessible, characterized in that the security tape (19) in the longitudinal direction of the tape in the edge region (20) of one or both sides is permeable to liquids and at least these permeable areas are anchored in the fiber composite of the security paper (23, 25). Security paper according to one of claims 1 or 2, characterized in that the security band (7, 19) is equipped with optically variable effects, in particular diffraction patterns, holograms or interference effects. Security paper according to one of claims 1 or 2, characterized in that the security tape (7, 19) is provided with printed images, in particular negative or positive characters. Security paper according to one of claims 1 or 2, characterized in that the security tape (7, 19) contains a metal layer. Security paper according to one of claims 1 or 2, characterized in that the security tape contains fluorescent, in particular daylight fluorescent substances. Security paper according to one of claims 2 to 6, characterized in that the liquid-permeable areas (20) are also fiber-permeable. Security paper according to Claim 1, characterized in that the paper webs (6, 9, 27, 28) have windows (16) in the region of the security band (7, 19). Security paper according to claim 2, characterized in that a film area (26) is provided in one of the edge areas and is anchored in the adjacent paper structure (25). A method for producing a security paper according to claim 1, characterized in that in a first method step, a first paper web is formed in a manner known per se, in which a security band is embedded in the paper during sheet formation and windows are formed by likewise known measures, through which the security band is partially freely accessible, - That a security tape with a width of greater than 2 mm is used and the width is dimensioned such that at least on the side of the paper web to be formed facing away from the screen in the area of the security tape during the paper production, defects already occur in the form of holes that the screen facing side of the paper web (front) but still has a flawless surface, - That at least a second paper web is formed parallel to the first method step, which is applied to the back of the first paper web and connected to it after completion of the first paper web, so that existing imperfections on the back are covered with this additional paper layer or brought into a defined shape , wherein the second paper web has a thickness of 10-50%, preferably 20%, of the total thickness of the security paper. - That a third paper web is optionally formed in parallel in the same way and connected to the other side of the paper web, and that - Connect further process steps, such as calendering, gluing, drying, etc. to complete the paper in a known manner. A method for producing a security paper according to claim 2, characterized in that - In a first process step, a paper web is formed, in which a security band is embedded in the paper during sheet formation, the security band being liquid or fiber-permeable in at least one edge area, but being impermeable in the middle area and being introduced on a track-like and narrower than that The safety band of the sieve increases so that the permeable edge areas protrude beyond the elevation, - That, if necessary, one or two further paper webs are formed parallel to the first process step, which are brought together with the first paper web after leaving the screening area and are firmly connected to the latter and - That the paper is finished in a conventional manner in further process steps. A method according to claim 10 or 11, characterized in that the additional paper web (s) have window areas which are brought into register with the exposed areas of the security band. A method for producing a security paper according to claim 10 or 11, characterized in that the screen on which the first paper web is formed has bumps which are narrower than the security band and that the permeable areas of the security band project laterally beyond the bumps. A method according to claim 10 or 11, characterized in that the security tape runs onto the screen outside the pulp. Method according to one of claims 10 or 11, characterized in that the elevation on which the security band runs is an elevated ring area of the screen. Method according to one of claims 10 or 11, characterized in that the security band is brought to the screen after about 30% of the sheet formation has been completed. Method according to claim 10 or 11, characterized in that the additional paper webs (9, 27, 28) are made homogeneous.

Images