EP0860298B1 - Security paper and method of fabrication of a security paper - Google Patents

Abstract

The security paper material has a security strip (7) in a width of more than 2mm, embedded in the first paper layer (6) of a multi-layer paper structure, with openings in the paper surface for at least partial exposure of the strip on both sides. The first paper layer (6) is covered by at least one further paper layer (9), and they are bonded together. The second paper layer (9) has a thickness of 10-50% of the total thickness of the security paper (15), and pref. 20%. Also claimed is a mfg. process where the initial paper layer is formed conventionally, and the security strip is embedded in the paper while it sets into a paper material, with windows formed where the security strip is accessible. The security strip, with a width more than 2 mm, with a width selected for the holes formed on the side away from the rotary fourdrinier while giving a smooth and unbroken paper surface on the side of the paper towards the fourdrinier. At least one further paper layer is produced in parallel with the first stage, to be applied to the reverse side of the first paper layer, to be bonded together covering the openings in the first paper surface or give a defined shape. Similarly, a third paper layer is formed to cover the other side, to be followed by further finishing processes such as calendering, glue application, drying, etc.

Description

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

For security papers, such as banknotes, securities, documents, ID cards etc., it is known as a security feature security elements, in Store form of threads, tapes or the like. Usually these threads or ribbons during the manufacture of the paper in it Paper introduced. In the case of rotary screening plants, the thread or the belt is included introduced into the pulp and brought up to the sieve in such a way that during the sheet formation is embedded in the fiber structure. This Storage procedure is well known and e.g. in EP-A1 0 279 880 (Crane) or EP-A1 0 492 407 (GAO).

Sometimes it is desirable that the security element be in the security paper is embedded that there is at least one point on the security paper is exposed on the surface. Instructs the security element optically variable effects, so their effect is at least partially exposing the security element considerably increased or in many Cases effective at all.

EP 0 229 645 A1 describes one possibility of such a security paper manufacture. For this purpose, two paper webs are separated from each other manufactured, the thickness ratio of the two webs approx. Is 1: 4. Then the two paper webs are brought together and at the same time the security thread between the layers of paper arranged. Laminating the paper webs creates a firm layer composite, where the security thread is very close to one of the paper surfaces is arranged. The thin layer of paper is before or after merging of the paper webs with window areas in which the security thread is freely accessible.

Another possibility, such a so-called window security thread To insert into a document is known from EP-A1 0 59 056 (portals). The security element is attached to the outside of the pulp Paper sieve, so that it is on raised areas on it, in the following text called hump, comes to rest. In the places where the security thread on the humps can be on the Do not form paper on the side facing the screen, so that it is precisely at these points in the later finished paper is freely accessible.

It is known that the incorporation of a security thread in practice in this respect Difficulties arise when the sheet formation above and below the thread is hindered because in the area of the thread the flow velocity the pulp significantly changed or reduced in the direction of the sieve becomes. The wider the thread to be stored, the more this affects. In order to guarantee a sufficiently good sheet quality, this is from the Processes known from EP-OS 0 059 056 are therefore restricted to threads whose width Not exceed 1 mm - 1.5 mm.

To enable the embedding of wide security tapes, in EP-PS 0 070 172 (portals) proposed the thread after the beginning embedding the classic technique described (sieve without hump) but to make special demands on the thread material to be embedded. The film-like security band is used in certain, periodically repeating partial areas designed to be liquid-permeable, so that fiber deposition remains unchanged in these areas in papermaking or sheet formation is possible in the impermeable areas but the formation of leaves is prevented. During the embedding of such Security tape thus form in the area of the liquid-impermeable Zones areas in which the tape is freely accessible on one side is.

Although very wide tapes are embedded in the paper with this process and can be made accessible in window areas it is disadvantageous that the homogeneity of the tape is affected by the periodic intended perforations in the longitudinal direction interrupted again and again becomes. This is a particular advantage of previous window security threads lost, which is that the optical effects of the tape (Negative writing, optically variable properties etc.) in incident light only in the Window areas can be checked, but also those embedded in the paper in transmitted light Areas are recognizable. Is the security thread or the security band applied homogeneously in the longitudinal direction, so it is in transmitted light as continuous bar recognizable and therefore easy to check. He instructs inhomogeneities in the areas embedded in the paper it is not very essential when it comes to reflected light / transmitted light so it is difficult to distinguish them from angry imitations.

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 a uniform appearance in the opening and Has transmitted light and a method for its production.

This object is solved by the features of the independent claims. Further training is the subject of the subclaims.

The basic idea of the invention is that in a known manner Security paper is formed with window security thread, in which the Security thread but is deliberately so wide that inevitably a Paper is created in the area of the security thread or security tape Defects in the form of arbitrary holes. Usually tried the expert to avoid such defects in any case. At the Security paper according to the invention are aware of these defects put up with it afterwards with one or two error-free To combine or connect layers of paper in such a way that all imperfections covered by the additional layer (s) or in a defined one Be brought into shape.

The invention is based on the surprising finding that in the Production of security papers with window security threads at Introducing threads or tapes that are becoming ever wider from a certain point Width of the belt first on the side facing away from the sieve (back) Flaws appear in the form of holes above the security band. at as the width of the band increases, the number and size of the band increase Flaws, but without the same defects on the screen facing the screen Side of the paper (face). Only after a further increase These errors occur simultaneously on both sides. Elevated if the width of the security band is further increased, in extreme cases there is no Area of the security band the sheet formation on both sides of the security band Completely.

One determines experimentally from which width of the security band the Errors on the back and from what width they also on the Front face, so you have the two limits in which you are in the simplest case when selecting the ones that can be used according to the invention Security bands can move.

Experience has shown that the first defects appear on the back from a width from about 1.5 - 2 mm. Without additional measures on the rotary screen system you can now with the usual mesh size of the sieve and usual height the hump increase the width of the safety band to about 4 - 5 mm before Flaws appear on the front of the paper.

With the solution according to the invention, it is now possible for the first time without any special additional measures on the circular screening plant to use security threads, instead of the previous 0.75-1 mm width, now a width of up to approx. 4 mm can have. By increasing the mesh size of the sieve (which is only possible within narrow limits with unchanged fiber length is) and change in height and shape of the humps are further increases the width possible without making mistakes on the front of the paper occur.

If even wider security tapes are to be used, according to one Further development of the invention proposed in the edge area of the security band additionally provide liquid-permeable areas that are not visible in the finished paper. This measure also helps still completely exposing the impermeable band area embedding and anchoring of the tape limited in the edge area possible. These measures now even give you the opportunity store security tapes of any width in the first paper layer in such a way that in extreme cases in the middle of the security band of are continuously accessible on both sides.

By applying additional layers of paper on one or both sides or without window areas, security paper variants can be produced, which are very different from previous ones. Because of that wide security tapes give the security papers a specific Appearance that clearly distinguishes them from others and that they are with cannot be reproduced by modern copiers.

The security paper according to the invention also has the advantage that by using much wider security tapes, especially when using windows at the same time, solely because of of the larger area are much easier to check. The bigger one But space also allows for more complex and complex Use printed images and optical effects, so that the imitation such security tapes is additionally difficult. Because such security papers also produced on conventional double circular paper machines can be, is the use of the inventive method without major additional production costs or investments possible.

Further advantages and advantageous developments are the subject of the dependent claims and 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.

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 sieve 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.

1 shows the schematic representation of a twin-round paper machine, as used for the production of security paper 15. The plant consists of two circular screen paper machines 1 and 2, which a take-off felt 3 are connected to one another.

A paper web 6 is formed from the circular wire 4 in the paper machine 1, in which a security band 7 is embedded. The security band 7 runs thereby on the hump 5 of the circular sieve 4 before the associated hump 5 or the respective screen area is immersed in the pulp 8 of the paper machine. The security band is located in the paper web 6 produced in this way in an inner layer 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 059056.

The paper machine 2 is used in parallel with the production of the paper web 6 a second paper web 9 is produced, which in the present example is homogeneous, i.e. without windows or the like. The paper web 9 will removed from the rotary screen 11 by means of the so-called take-off felt 10, in Area of the pressure roller 12 connected to the paper web 6 and together with this the other processing stations (calender, paper sizing etc.) fed to the manufacturing plant.

Fig. 2 shows a detail of the circular screen 1, in which the described Introduction of the security band 7 can be seen somewhat more clearly is. In particular, it is shown that in the areas where the Safety tape 7 on which the hump 5 rests, no sheet formation is possible, because due to the intimate contact between security band 7 and Hump 5 can not deposit fibers. These contact surfaces form on paper the window areas where the security tape later free will be accessible. The bumps 5 in the sieve 4 are usually essential made wider than the security band. This is the introduction of the security band possible within a wide tolerance range. ever according to the shape of the bumps 5 and their arrangement with one another in the circumferential track of the circular sieve 4 are the number and position of the window areas in the later paper can be planned specifically.

As mentioned at the beginning, the sheet formation is in the area of the security thread or security band depending on the width of the security band, because the usually liquid-impermeable band 7 the drainage hindered by the sieve 4. The skilled worker is aware that at Use of security tapes that are too wide Errors in the form of holes occur can expose the security band. Since the first mistakes already a width of about 1.5 mm are expected, are therefore usually Security threads with a width of up to 1 mm are used.

More detailed studies have now shown that when the Security thread width not as expected on both sides of the security band, i.e. the side 13 facing the screen 4 and the side facing away from the screen Page 14, errors in the form of holes occur at the same time. Surprisingly the errors first appear on the back of the security band, i.e. in the layer area 14 of the paper web. Only after more clearly Enlargement of the security bandwidth is also the sheet formation in the Layer area 13 influenced so that there in addition to the deliberately generated Random holes appear in window areas. If you increase it The width of the security band continues, so take number and size of the holes continue on both sides of the paper web until finally in the area of the Safety band completely prevents sheet formation on both sides is.

According to the invention, security tapes are now used in a first embodiment used, whose width is chosen so large that on the back the later security paper, i.e. in area 14 of the security band 7, defects in the form of holes occur, but such errors still not on the front, i.e. in area 13. such Security tapes preferably have a width of 2 mm - 4 mm.

If you cover the faulty back of the security paper produced in this way with the paper web 9 produced in the second circular screening plant, see above there is always a minimum paper thickness in the area of the defects, which gives a homogeneous impression of the paper surface. The mistakes in the paper web 6 are thus hidden from the later viewer.

3 shows a security paper with an embedded window security tape in top 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 is paper made by a conventional process in which "erroneously" a security tape with a width of 4 mm was embedded, for example, this has a defect in area 18, which is shown in FIG. 4 similar to the window area 16 exposes the security band.

Fig. 5 shows the same section AB of the security paper, but with the Prerequisite that this security paper according to the inventive method was produced. In this embodiment, the flaw is 18 covered with the additional paper web 9. Paper web 6 and paper web 9 are shown differently hatched in FIG. 5, when finished However, paper cannot be identified as separate layers of paper because two paper webs merged shortly after the sheet formation in the following processing steps (calendering, gluing, drying, etc.) in this way intimately connect that separation or distinction of the individual tracks is no longer possible. By overlaying these two Layers thus create the impression of a paper web produced without defects.

Fig. 6 shows a special embodiment of a security band 19, the much wider than the originally defined security band is. This security band 19 is 20 mm or 30 mm wide, for example. It has in the edge areas 20 liquid-permeable and ideally even permeable areas. The band is in the middle region 21 executed impermeable to liquids.

Such a security band 19 can, for example, consist of a film strip be made, the liquid in the edge area by perforation or was made permeable to fibers. Alternatively, a liquid or fiber-permeable fabric tape can be used, the 21 liquid impermeable due to special impregnation or coating have been done.

Claims (14)

1. A method for producing an antifalsification paper (15) with a safeguarding band (7, 19) partly embedded in the antifalsification paper (15), having the following steps:

   forming on a wire (4) a first paper web (6) having a front (13) facing the wire (4) and a back (14) facing away from the wire (4),

   embedding during sheet forming a safeguarding band (7, 19) with a width greater than 2 mm such that predefined windows (16) are formed on the front (13) of the first paper web (6) through which the safeguarding band (7, 19) is freely accessible, while fortuitous flaws (18) in the form of holes are accepted on the back (14) of the first paper web (6) in the area of the safeguarding band (7, 19),

   forming a second paper web (9) which is applied, after completion of the first paper web (6), to the back (14) of the first paper web (6) and connected therewith so that the fortuitous flaws (18) are covered, the second paper web (9) having a thickness of 10 to 50% of the total thickness of the antifalsification paper (15).
2. A method for producing an antifalsification paper (15) with a safeguarding band (7, 19) partly embedded in the antifalsification paper (15), having the following steps:

   forming on a wire (4) a first paper web (6) having a front (13) facing the wire (4) and a back (14) facing away from the wire (4),

   embedding during sheet forming a safeguarding band (7, 19) with a width greater than 2 mm such that predefined windows (16) are formed on the front (13) of the first paper web (6) through which the safeguarding band (7, 19) is freely accessible, while fortuitous flaws (18) in the form of holes are accepted on the back (14) of the first paper web (6) in the area of the safeguarding band (7, 19),

   forming a second flawless paper web (9) which is applied, after completion of the first paper web (6), to the back (14) of the first paper web (6) and connected therewith, the second paper web (9) being designed so that the fortuitous flaws are brought in a predefined form, and the second paper web (9) having a thickness of 10 to 50% of the total thickness of the antifalsification paper (15).
3. A method according to claim 1 or 2, characterized in that the second paper web (9) has a thickness of 20% of the total thickness of the antifalsification paper (15).
4. A method according to at least one of claims 1 to 3, characterized in that one or more further paper webs with or without window areas (16) are applied to the front and/or back of the antifalsification paper (15).
5. A method according to claim 4, characterized in that the further paper webs have window areas (16) which are brought to coincidence with the exposed areas of the safeguarding band (7, 19).
6. A method according to at least one of claims 1 to 5, characterized in that the wire (4) on which the first paper web (6) is formed is a cylinder and has bumps (5) onto which the safeguarding band (7, 19) runs.
7. A method according to claim 6, characterized in that the safeguarding band (19) has liquid-permeable areas in the edge area (20), and the bumps (5) are narrower than the safeguarding band (19) so that the liquid-permeable areas of the safeguarding band (19) protrude laterally beyond the bumps (5).
8. A method according to at least one of claims 1 to 7, characterized in that the safeguarding band (7, 19) is brought against the wire (4) after about 30% of the sheet forming of the first paper web (6) is over.
9. A method according to at least one of claims 1 to 7, characterized in that the safeguarding band (7, 19) runs onto the bumps (5) outside the pulp (8).
10. An antifalsification paper (15) having a partly embedded safeguarding band (7, 19), wherein

    the safeguarding band (7, 19) has a width greater than 2 mm,

    the antifalsification paper (15) is composed of at least a first and a second paper web (6, 9), the back (14) of the first paper web (6) being covered with the second paper layer (9) and firmly connected therewith, and the front (13) of the first paper layer (6) being freely accessible,

    the safeguarding band (7, 19) is embedded in the first paper layer (6), whereby the safeguarding band (7, 19) is freely accessible in predefined windows on the front of the first paper layer (6), the back (14) of the first paper layer (6) can have fortuitous flaws in the form of holes in the area of the safeguarding band (7, 19), and the second paper layer (9) has a thickness of 10 to 50%, preferably 20%, of the total thickness of the antifalsification paper (15).
11. An antifalsification paper (15) according to claim 10, characterized in that the safeguarding band (7, 19) is equipped with optically variable effects, in particular diffraction patterns, holograms or interference effects.
12. An antifalsification paper (15) according to claim 10, characterized in that the safeguarding band (7, 19) is equipped with printed images, in particular negative or positive characters.
13. An antifalsification paper (15) according to claim 10, characterized in that the safeguarding band (7, 19) contains a metal layer.
14. An antifalsification paper (15) according to claim 10, characterized in that the safeguarding band (7, 19) contains fluorescent, in particular daylight fluorescent, substances.

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