EP1468141B2 - Security paper and method and device for producing the same - Google Patents

Abstract

Security paper comprises an opening made during production and with our any sharp edges, reducing the possibility of falsification. Security paper comprises an opening made during production and with our any sharp edges. Independent claims are included for valuable documents made using this paper, a paper sieve with a closure element for making the paper and the production of the paper by forming paper on a sieve with a closure element in order to form an opening.

Description

The invention relates to a security paper for the production of security documents, such as banknotes, identity cards or the like, with a through opening and a method and an apparatus for producing such a security paper. Furthermore, the invention relates to a document of value, such as a banknote, identity card or the like, with a through opening.

In the WO 95/10420 a document of value is described, in which after its manufacture a continuous opening is punched, which is then closed on one side with a covering film projecting on all sides. The cover film is transparent at least in a partial area, so that when attempting to copy the document of value, the substrate shines through and reproduced by the copying machine accordingly. In this way counterfeits can be easily detected.

However, this known value document has the disadvantage that the opening produced by punching can also be generated by a counterfeiter. Although the color copy of a true value document no longer has the transparent area, this area can subsequently be punched out analogously to the real value document and closed again with a suitable cover film. Forgeries are therefore difficult to recognize.

The invention has for its object to propose a security paper and a document of value, which has an increased security against counterfeiting compared to the prior art.

This object is solved by the features of the independent claims. Further developments are the subject of the dependent claims.

The basic idea of the invention is that by creating a "window opening" during sheet formation, i. during papermaking, the edge region of the opening has characteristic irregularities which subsequently can not be produced on the finished paper. The irregularities are manifested by the lack of a sharp cutting edge or by irregular attachment of the fibers in the edge region and by protruding into the opening of individual fibers. A rough check of this characteristic edge structure is already possible with the naked eye, an exact test can be done with a magnifying glass.

With the edge structure according to the invention it can be ensured that the opening can not be produced by subsequent punching of a paper sheet. An opening created in this way therefore has a similar security value to a watermark produced during papermaking or to a security thread embedded in papermaking.

Security paper is usually made in wide webs with multiple benefits side by side. The webs are cut into sheets upon completion, on which e.g. 6 x 9 benefits are available. These sheets are printed and then cut into single pieces.

If each individual benefit to have a through opening, are provided on the screen of the paper machine correspondingly many elements that prevent the formation of sheets exactly in the surface areas in which the opening is needed. If the security paper also have watermarks, production generally takes place on so-called "round-screen paper machines" in which the wire is mounted on a rotating drum. The opening may be in the area of the watermark in this case.

The security paper according to the invention has at least one through opening produced during papermaking. In order to be able to produce this opening, the screen of the paper machine must be provided per use with at least one water-impermeable, preferably elastic or movably mounted closure element. The closure element prevents the formation of sheets in this area. So that no fibers are deposited on the closure element during sheet formation, it is preferably formed so high that it protrudes clearly beyond the paper surface. When removing the paper web through the pick-up roller covered with the pick-up felt, however, it must be ensured that the closure element does not hinder the contact between the moist and still very unstable paper web and the pick-up roll, since the paper web otherwise breaks in this area. For this reason, the closure element according to the invention consists of a highly elastic material, which can be compressed by the pick-up roller to about the level of the paper surface. Alternatively, the closure member consists of a movably mounted, preferably rigid plastic or metal element, which is lowered either by the pressure of the take-off roll itself or by electronic control in contact with the pick-up roll to about the level of the paper surface or below.

Further possibilities for producing the opening are closing the sieve surface with a plastic material, such as a lacquer, wherein the plastic material in the context of the invention is also to be understood as a closure element. Alternatively, rigid closure elements of the size of the opening to be formed may be applied (e.g., soldered) onto the screen surface having a thickness significantly greater than the thickness of the paper web.

Under certain circumstances, it may be helpful to provide further drainage-reducing structures in the edge area of the closure elements, which create a type of predetermined breaking point in the paper web. Because the cotton fibers used primarily for security papers have the tendency to lay uncontrollably over the closure elements, whereby the formation of holes is prevented or at least made more difficult.

The dewatering-inhibiting structures may be, for example, special embossments in the paper screen, additional screen elements, possibly with a different mesh size than the original paper screen, or plastic structures. In principle, all conceivable structures are useful, which delay the drainage, and thus form a bright yard around the opening to be created. In some cases, it is already sufficient to use only the drainage-inhibiting structures. For example, an annular embossing can be designed so that when the paper web is removed from the wire, the hole according to the invention is produced.

The paper web lying on the pick-up felt with the openings formed on account of the closure elements is subsequently used in further process steps, e.g. Calendering, gluing and drying to a self-supporting paper web further processed. In order to improve the formation of holes, in addition to or as an alternative to the dewatering-resistant structures additionally used in papermaking, fibers protruding into the desired opening after paper formation, e.g. be removed by punching or cutting, the fibers are removed only so far that the papermaking edge of the hole is not destroyed or even completely removed. For example, if you want to create a circular hole and a fine web of fibers settles irregularly over the hole, you can use a circular die whose diameter is smaller than the desired hole to remove the interfering fiber. It is always, if necessary, only in a partial region of the hole edge, a papermaking generated hole edge recognizable. The security paper according to the invention therefore has at least one opening whose edges are at least partially irregular and show a character similar to hand-made handmade paper, in contrast to the sharp edges of a punched or cut opening.

The fibrous, irregular edge of the openings is visually recognizable and therefore serves as an easy to check authenticity feature. If the security against counterfeiting is to be further increased, at least one watermark can additionally be formed in the vicinity of the opening, or the opening can be generated in a watermark area. Depending on the type of watermark to be generated, different measures on the paper screen are necessary for this. For the production of two-level watermarks with a strong light / dark effect, metal wires or metal moldings (so-called electro-types) are soldered onto the paper wire. For the production of multi-level watermarks, however, a three-dimensional relief is formed in the paper screen. Combinations of screen embossing and other sheet-preventing measures, such as electro-types or the application of sealing compound, are also used in watermark production. The resulting light-dark modulation in the security paper in the immediate vicinity of the opening presents the counterfeiter with hardly solvable tasks.

The shape of the watermark can be chosen so that it is in a meaningful context with the outline contour of the opening or that opening and surrounding watermark form a coherent motif.

Preferably, the paper screen is a round screen. However, since the closure member is either elastic or at least movably mounted, the invention may be readily used in a fourdrinier paper machine.

The aim of the invention to prevent counterfeiting documents of value with an opening or greatly aggravate, can also be achieved by a larger, thinner area generated in the security paper by appropriate Siebprägung and / or Entwässerungsbehinderung with electric types and the opening of the invention is provided in this area , wherein the thin paper area projects beyond the opening at least on one side, preferably on all sides, so that when the security paper is viewed in transmission, the thin paper area contrasts with the remaining surrounding paper web. The opening is created in this case, as already described, during papermaking.

The thinner area in the security paper can have a uniform thickness or be designed as a multi-level watermark. If the security paper consists of a two-ply paper, it is also possible to provide a layer, preferably the thicker, with a hole which is subsequently covered by the second paper ply with an opening according to the invention whose dimensions are smaller than those in the first Paper layer produced hole.

Of course, in two-ply paper consisting of a thinner and a thicker layer, the hole of the invention may also be in the thinner layer.

The opening according to the invention may be composed of several partial openings which are separated from one another by paper webs. The partial openings may have any outline contours and are preferably used as an additional design element. For the production of the respective partial openings, all the above-mentioned methods for producing the opening according to the invention can be used analogously.

According to a preferred embodiment of the invention, the opening is provided at least on a surface of the security paper after its production with a security element projecting beyond the opening. This security element can consist of a simple transparent plastic film or else be embodied as a multilayer security element which has one or more visually and / or machine-testable security features.

This security feature may be diffractive structures, such as reflection or reflection Transmission holograms, observed in reflection grating structures or volume holograms, thin-film elements or filter elements, such as polarizing filter or interference filter act. In particular, the filter elements have the advantage that they can be used for checking further safety features provided on or in the security paper, in which the opening is brought into coincidence with this further security feature by folding the security paper. However, the security element arranged in the region of the opening can also carry a simple imprint or a moire pattern as a security feature. The colors used for this imprint may include a fabric having optically variable, luminescent, electroconductive or magnetic properties. The optically variable substances may in particular be interference layer pigments or liquid crystal pigments.

The security feature may further consist of a metallization, wherein also several different colored metals can be used. Also a screening of the metal layers or reflection layers of diffraction structures is possible. Of course, any semitransparent layers can also be used. The security feature may also consist of a perforation or a lens structure.

Preferably, a sufficiently large area of the security element is kept completely transparent in order to be able to easily recognize counterfeits which have been produced by means of a color copier. Because a copy does not have this transparent area.

The security element may be formed, for example, as a self-supporting label or stamping foil element, which projects beyond the opening on all sides by a certain amount. In this solution, it is advantageous if the security paper in the region of the support surface of the security element has a recess, so that the security paper has a stepless surface in this area. In an extreme case, the security element can completely cover the security paper or the value document. This solution can also be provided on both sides of the security paper or value document.

The recess can be created by compressing the security paper in this area before applying the security element. But it is also particularly easy to produce the recess during papermaking by obstructing the formation of sheets in the immediate vicinity of the opening and thus forming a thinner spot in the paper.

According to a further embodiment, the security element can also be strip-shaped and extend over the entire length or width of the security paper. This variant is particularly useful when the security element is applied to the still uncut security paper in an endless form. In this case, the security element can be laminated in a continuous process on the security paper by means of hot stamping.

The outline contour of the security element can be chosen arbitrarily. For example, it may coincide with the contour of the opening or be meaningful with a watermark surrounding the opening. Also security element and watermark can form a coherent motif. Thus, the security element or opening and the watermark together can give the impression of a stylized sun, when the security element or the opening are made round and the watermark areas are arranged radially around the opening.

The same applies to the security feature applied in the area of the security element. For example, the security element can carry a print as a security feature, which is repeated in the form of the watermark.

The opening and / or the security element can be round, oval, rectangular, trapezoidal or star-shaped. Of course, any other outline contour is possible.

If both sides of the opening are provided with a security element, then the same or the same type of security element can be applied to both sides or different. The following combinations are preferred: page 1 Page 2 self-supporting plastic film, possibly with one or more security features; in label or strip form or over the entire surface self-supporting plastic film, possibly with one or more security features; in label or strip form or over the entire surface self-supporting plastic film, possibly with one or more security features; in label or strip form or over the entire surface Stamping foil element; in label or strip form or over the entire surface Self-supporting plastic film, possibly with one or more security features in label or strip form or over the entire surface Coating or imprint of a resin or a printing ink containing visually and / or mechanically testable substances (eg liquid crystal or interference layer pigments, luminescent substances); in label or strip form or over the entire surface

The security paper according to the invention can be further processed into any valuable documents such as banknotes, stocks, identity cards, credit cards, security labels, coupons, etc. It can also be used in the field of product protection for counterfeiting of any goods.

Further advantages and embodiments will be explained with reference to FIGS.

Fig. 1

erfindungsgemäßes Wertdokument in Aufsicht,

Fig. 2

Schnitt durch dieses Wertdokument entlang A - A,

Fig. 3

erfindungsgemäße Vorrichtung zur Herstellung des erfindungsgemäßen Sicherheitspapiers,

Fig. 4

erfindungsgemäßes Verschlusselement gemäß der Einzelheit B in Fig. 3,

Fig. 5

alternative Ausführungsform des Verschlusselements,

Fig. 6

Einzelheit B gemäß Fig. 3 mit zusätzlicher Siebprägung in der Umgebung des Verschlusselements,

Fig. 7

Querschnitt durch ein Sicherheitspapier, das mittels des in Fig. 6 dargestellten Papiersiebs hergestellt wurde,

Fig. 8

Aufsicht des in Fig. 7 dargestellten Sicherheitspapierauschnitts,

Fig. 9

weitere Ausführungsform des erfindungsgemäßen Sicherheitselements im Querschnitt entlang der Linie A - A in Fig. 1,

Fig. 10

weitere Ausführungsform des Sicherheitspapiers im Querschnitt,

Fig. 11

weitere Ausführungsform des Sicherheitspapiers im Querschnitt,

Fig. 12

weitere Ausführungsform des erfindungsgemäßen Wertdokuments.

Show it:

Fig. 1

Inventive value document in supervision,

Fig. 2

Section through this value document along A - A,

Fig. 3

Inventive device for producing the security paper according to the invention,

Fig. 4

Inventive closure element according to the detail B in Fig. 3 .

Fig. 5

alternative embodiment of the closure element,

Fig. 6

Detail B according to Fig. 3 with additional screen embossing in the vicinity of the closure element,

Fig. 7

Cross section through a security paper, which by means of in Fig. 6 paper screen was produced,

Fig. 8

Supervision of in Fig. 7 illustrated security paper cutout,

Fig. 9

further embodiment of the security element according to the invention in cross section along the line A - A in Fig. 1 .

Fig. 10

further embodiment of the security paper in cross section,

Fig. 11

further embodiment of the security paper in cross section,

Fig. 12

another embodiment of the value document according to the invention.

Fig. 1 shows an inventive document of value in supervision. In the example shown, it is a banknote 1. This banknote 1 has a through opening 2. This opening was created during the manufacture of the security paper used for the banknote 1 and therefore has a fibrous, irregular edge 14. This edge 14 is formed in the sheet formation of the paper used for the banknote and can not be produced by subsequent punching or cutting of the paper.

Fig. 2 shows the banknote 1 in cross section along the line A - A. Here it is clear that the opening 2 is continuous.

Fig. 3 shows the schematic representation of a round screening paper machine 3, as it is preferably used in the manufacture of the security paper 10 according to the invention. The device 3 consists essentially of the paper wire 4 and the pickup roller 5, via which the pick-up felt 6 is stretched.

The paper screen 4 has closure elements 7, which prevent the sheet formation during immersion of the paper screen in the paper pulp 8 and thus produce the openings 2 according to the invention. The closure elements 7 are designed so that they do not hinder the removal process of the paper web 10 in the region of the take-off roll 5. Since the paper web 10 is still very unstable at this time and has a low strength, care must be taken for a tensionless contact between the paper web 10 and the pick-up felt 6.

Fig. 4 shows the detail B of Fig. 3 in enlarged form. The closure element 7 shown here is fastened on the surface of the sieve 4. It consists of a pot-shaped element in which a further cup-shaped element is incorporated. The two elements are pressed apart by a spring 9, so that they with their edge areas collide.

Fig. 5 again shows the closure element 7 in the pressed state. The closure element 7 is pressed against the pressure of the spring 9 below the level of the paper screen surface 4. The pressure is preferably generated by the take-off roller 5. That is, the closure member 7 is pressed in contact with the pickup roller 5 down and thus hindered in any way the distortion-free removal of the paper web 10 through the pick-up felt. 6

Fig. 6 shows a further embodiment of the paper strainer 4 according to the invention by means of an enlargement of the detail B, the Fig. 3 , In this case, the papermaking screen 4 additionally has a watermark embossing 11 in the vicinity of the closure element 7. In the example shown, the watermark 11 is arranged symmetrically around the closure element 7. However, any other embodiment of the watermark 11 is possible. The watermark embossing 11 causes the deposition of paper fibers in different thicknesses in the sheet formation, so that the finished paper web is modulated in this area and shows the typical for watermark on / transmitted light effect.

Fig. 7 shows one using the in Fig. 6 This paper web 10 has an opening 2 which has been produced by the closure element 7. In contrast, the modulated paper regions 12 were generated by the watermark embossing 11. These paper areas, which are referred to below as "watermarks 12", can be directly related to the opening 2, or the opening 2 and the watermark 12 can together form a motif, as can be seen in FIG Fig. 8 is shown in supervision. The opening 2 has a round outline and is surrounded by a radial watermark 12, so that the motif of a sun arises.

Fig. 9 shows a further embodiment of the in Fig. 1 shown value document 1 in cross-section along the line A - A. In this case, the opening 2 is closed on one side by a security element 13. This security element 13 is preferably arranged in a recess 15 which surrounds the opening. This depression 15 can be produced by subsequent calendering of the paper web 10, ie by compression of the paper fibers.

Alternatively, the recess 15 may also be created by actually reducing the paper thickness in this area. This is most easily done directly during the manufacture of the paper web 10, by making the sheet formation in this area thinner by appropriate design of the screen. This can be done by corresponding embossments 16 in the paper 4.

That in the 4 and 5 shown closure element 7 can be realized in various ways. So it is also conceivable that it is realized by a foam-like plug, which is compressed by the take-off roller 5. This element is glued to the paper screen 4 and also prevents in this area the formation of sheets. But it can also be realized by a cup-shaped, elastic element which is zusarnmengepresst by pressure and then returns to its original shape.

The security element 13 may be formed in one or more layers and has at least one paper or plastic layer. Preferably, the security element 13 in the region of the opening 2 to a larger transparent area, which serves on the one hand as a copy protection and on the other hand makes the opening edge recognizable from both sides. In addition, the security element 13 may be provided with any security features.

Fig. 10 shows an embodiment of the security paper not covered by the invention in cross section. The paper web 10 has a region 16 with a lower paper thickness compared to the rest of the paper web. In the entire area 16, however, the paper thickness is almost uniform. This thin region 16 can be produced by appropriate Siebprägung or Entwässerungsbehinderung during the production of the paper web 10. In this thinner area 16, the opening 2 is subsequently introduced. The edge contours 17 of the opening 2 are in the Fig. 10 indicated by dashed lines. In this case, care must be taken that the region 16 projects beyond the opening 2 at least in a partial region in order to be able to carry out a corresponding check of the authenticity of the paper web 10 when viewed in transmission.

Fig. 11 shows an embodiment not embraced by the invention of the security paper, wherein the security paper in this case consists of two paper layers 18,19. The two paper layers 18, 19 are each produced on separate round screens and brought together immediately after removal from the paper screen and subsequently further processed together. In the first paper web 18, a hole 20 is generated with the already explained aids during sheet formation on the round screen. When merging the two paper webs 18,19 this hole 20 is closed again on one side. After the completion of the security paper, the opening 2 is introduced into the second paper web 19. The edges 17 of the opening 2 are also shown in dashed lines in this figure. The opening is here produced by cutting or punching, analogous to the in Fig. 10 illustrated embodiment is to ensure that the edges 17 and cutting edges of the opening 2 are in the region of the hole 20.

Fig. 12 shows a further embodiment of the erfindungsgmäßen value document 1 in supervision. The opening 2 is composed in this example of several partial openings 21, 22, 23, which are separated by paper webs 24. These partial openings 21, 22, 23 can be produced analogously to the variants for the opening 2 described above.

Claims (36)

1. A security paper having cotton fibers for producing security documents, such as bank notes, identity cards or the like, having at least one through opening, wherein the opening has been produced during paper-making and has fibers irregularly accumulated in the edge area, individual fibers protruding into the opening, and no sharply cut edge in the edge area.
2. The security paper according to claim 1, characterized in that the security paper has at least one watermark in the surroundings of the opening.
3. The security paper according to claim 2, characterized in that the security paper has a smaller paper thickness in the area of the watermark.
4. The security paper according to at least one of claims 1 to 3, characterized in that the opening and the surrounding watermark are meaningfully related or form a connected motif.
5. The security paper according to at least one of claims 1 to 4, characterized in that the security paper has a predetermined paper thickness and an area with a smaller paper thickness in comparison with the predetermined paper thickness, and the opening is disposed in the area of smaller paper thickness and its dimensions are smaller than those of the area of smaller paper thickness.
6. The security paper according to at least one of claims 1 to 5, which is formed from two paper layers, wherein the first paper layer has a hole which has been produced during paper-making and is sealed on one side by the second paper layer, wherein the security paper has in the area of the hole a through opening whose dimensions are smaller than those of the hole produced in the first paper layer.
7. The security paper according to at least one of claims 1 to 6, characterized in that the opening consists of several partial openings.
8. The security paper according to at least one of claims 1 to 7, characterized in that the opening bears at least on one surface of the security paper, after production thereof, a security element protruding beyond the opening.
9. The security paper according to at least one of claims 1 to 8, characterized in that the security paper has a depression surrounding the opening, in which depression the security element is disposed.
10. The security paper according to at least one of claims 1 to 9, characterized in that the security element has at least one layer made of paper or plastic.
11. The security paper according to at least one of claims 1 to 10, characterized in that the security element has at least one security feature.
12. The security paper according to at least one of claims 1 to 11, characterized in that the security feature consists of a diffraction structure, a thin-film element, a polarizing filter or a print having at least one substance with optically variable, luminescent, electrically conductive or magnetic properties.
13. The security paper according to at least one of claims 1 to 12, characterized in that the security feature and the watermark surrounding the opening are meaningfully related or form a connected motif.
14. The security paper according to at least one of claims 1 to 13, characterized in that the security element is a label or an embossed foil element.
15. The security paper according to at least one of claims 1 to 14, characterized in that the opening and/or the security element is of circular, oval, rectangular, trapeziform or star-shaped configuration.
16. The security paper according to at least one of claims 1 to 15, characterized in that the security element is configured in a strip shape.
17. The security paper according to at least one of claims 1 to 16, characterized in that the security element has at least one transparent area in the area of the opening.
18. The security paper according to at least one of claims 1 to 17, characterized in that the opening bears on both surfaces (sides) of the security paper, after production thereof, a security element protruding beyond the opening, wherein the security element on the first surface (first side) is preferably a self-supporting plastic foil, and the security element on the second surface (second side) is preferably a coating or a print made of a resin or a printing ink which contains visually or machine testable substances.
19. The security paper according to at least one of claims 1 to 17, characterized in that the opening bears on both surfaces (sides) of the security paper, after production thereof, a security element protruding beyond the opening, wherein the security element on the first surface (first side) and on the second surface (second side) is preferably a self-supporting plastic foil.
20. A value document, such as a bank note, identity card or the like, having at least one through opening, wherein the opening has been produced during production of the cotton fiber-containing security paper used for the value document, has irregularly accumulated fibers and individual fibers protruding into the opening, as well as no sharply cut edge in the edge area.
21. The value document according to claim 20, characterized in that the opening is disposed in a watermark area of the value document.
22. The value document according to at least one of claims 20 to 21, characterized in that the opening bears at least on one surface of the value document, after production thereof, a security element protruding beyond the opening.
23. The value document according to at least one of claims 20 to 22, characterized in that the value document has a print which extends both over the security element and over the adjacent value document material.
24. A method for producing a security paper having a through opening, wherein the method has the following steps:

    - furnishing the paper-making mesh with at least one elastic or movably mounted sealing element in whose edge area there is present, where applicable, a further drainage-reducing structure which prevents the accumulation of paper pulp in said area,

    - forming on the paper-making mesh a paper web having cotton fibers which has a through opening in the area of the sealing element and fibers irregularly accumulated in the edge area and individual fibers protruding into the opening,

    - removing the paper web from the paper-making mesh by a take-off roll, thereby deforming the sealing element or lowering it into the mesh area such that the paper web remains intact.
25. The method according to claim 24, characterized in that at least one watermark is formed in the surroundings of the opening.
26. The method according to claim 24 or 25, characterized in that

    - there is formed a paper web with a predetermined paper thickness which has an area with a smaller paper thickness in comparison with the predetermined paper thickness,

    - and in said area of smaller paper thickness the opening is produced whose dimensions are smaller than those of the area of smaller paper thickness.
27. The method according to claim 24, 25 or 26, characterized in that

    - there is formed on a first paper-making mesh a first paper web having at least one hole,

    - there is formed on a second paper-making mesh a second paper web,

    - the first and second paper webs are combined to form the security paper, with the second paper web covering the hole in the first paper web on one side,

    - in the area of the hole of the first paper web the security paper then bears a through opening whose dimensions are smaller than those of the hole produced in the first paper web.
28. The method according to at least one of claims 24 to 27, characterized in that the through opening is composed of several partial openings.
29. The method according to at least one of claims 24 to 28, characterized in that the opening is sealed at least on one surface of the security paper, after production thereof, with a security element protruding beyond the opening.
30. The method according to at least one of claims 24 to 29, characterized in that the surroundings of the security paper directly adjacent to the opening are furnished with a depression using watermark technology.
31. The method according to at least one of claims 24 to 30, characterized in that the security element is disposed in the depression.
32. A method for producing a value document, such as a bank note, identity card or the like, having at least one through opening, wherein a security paper is produced according to at least one of claims 24 to 31 which is then, in further method steps, cut into sheets of predetermined size, printed and finally cut into the individual value documents.
33. A paper-making mesh for producing a security paper having a through opening, which has a paper-making mesh which bears at least one elastic or movably mounted sealing element in whose edge area there is present, where applicable, a further drainage-reducing structure which prevents the accumulation of paper pulp in said area.
34. The paper-making mesh according to claim 33, characterized in that the sealing element is an elastically deformable plastic element protruding beyond the mesh surface, or that the sealing element is a metal or plastic element protruding beyond the mesh surface and having a spring via which the sealing element can be lowered into or under the surface of the paper-making mesh by corresponding action of pressure.
35. The paper-making mesh according to at least one of claims 33 to 34, characterized in that the paper-making mesh is a cylinder mould.
36. An apparatus for producing a security paper having a through opening, which has a paper-making mesh which bears at least one elastic or movably mounted sealing element in whose edge area there is present, where applicable, a further drainage-reducing structure which prevents the accumulation of paper pulp in said area.

Images