ES2607492T3 - Drainer sieve and procedure for the manufacture of a drainer sieve - Google Patents

Abstract

Drainer screen (20) for papermaking, with at least one safety feature, with - a support screen (22), which includes a metal gauze (24) with an insertion zone, - an insertion element (32 ) arranged in the insertion zone of the metallic gauze to generate the at least one safety feature on the paper and - an injection molding around plastic (34) or a rear plastic injection molding (36) of the insertion element ( 32), which joins the insertion element (32) with the support screen (22).

Description

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DESCRIPTION

Drainer sieve and procedure for the manufacture of a drainer sieve

The invention relates to a draining screen for the manufacture of paper with at least one safety feature. The invention also relates to a process for manufacturing a draining screen, as well as a process for making paper with a safety feature using such a draining screen.

In the manufacture of paper in round machines or flat-table machines, paper pulp accumulates continuously on a mobile draining screen and solidifies until it can be removed from the draining screen as a wet paper web for subsequent treatment. Especially security papers for banknotes, identity documents and the like are designed for protection purposes frequently with watermarks or through holes allow to verify the authenticity of the security paper and serve at the same time as protection against reproduction illegal.

The safety features introduced in papermaking present in this case typical features. Thus, for example, the passage openings that are generated during papermaking include characteristic irregularities in the area of edges that are generated by irregularly adding fibers in the edge area and by means of individual fibers entering the opening, such as example in WO 03/054297.

If sharp edge holes are generated on a paper then a laser cutting or separate stamping stage is necessary for this, in addition to a higher expense for the additional work stage it also reaches oscillations in registration between the safety features generated by the make the paper and the characteristics generated by laser cutting or stamping.

In document DE 10 2006 058 513 A1 a draining screen for the manufacture of paper with multi-level watermarks is disclosed, with a support screen, which presents in a partial area a relief of several levels in the form of the mark of Water to be generated. The multi-level relief is formed by a perforated watermark insert, injection molded.

Starting from this, the invention is based on the objective of creating a draining screen of the type mentioned at the beginning that avoids the inconveniences of the state of the art. Particularly, the draining screen should allow a simple manufacture of paper with security features, and ideally an adequate combination of security features with different visual aspects.

This objective is solved with the characteristics of the independent claims. The improvements of the invention are the subject of the dependent claims.

According to the invention a draining screen for the manufacture of paper with at least one safety feature includes

- a support screen, which includes a metal gauze with an insertion zone,

- an insertion element arranged in the metal chiffon insertion zone to generate the at least one safety feature on the paper, and

- a plastic extrusion coating or plastic rear injection molding of the insertion element, which joins the insertion element with the support screen.

The safety features generated within the scope of the invention particularly comprise watermarks, holes with sharp edges in the paper and holes with characteristic irregularities in the area of edges. With particular advantage the drainer screen is designed to generate several security features on the paper that can present different visual aspects in each case although, however, due to the simultaneous generation during papermaking and very adequate registration tolerances during Injection molding around or rear injection molding are on record with respect to each other. Several security features may refer particularly to each other or complement each other. For example, a first security feature may repeat the form or design of a second security feature or supplement global information.

As will be explained more precisely below to generate such safety features by means of plastic injection molding around or rear plastic injection molding according to the invention, multiple different insertion elements can be integrated into a support screen, particularly also those elements of insertion, which due to its quality of material or its shape cannot be integrated with conventional techniques in the desired support screen. The invention offers special advantages, for example, in cases where the metal gauze of the support screen and the insertion element are made of different materials. For example, metal gauze and the insertion element can be composed of different metals, such as a bronze metal gauze and a steel insert. In other advantageous configurations, the support screen may consist of metal and the plastic insert, or

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conversely, the plastic support screen and the metal insert element.

In the case of a variant of the advantageous invention, the insertion element comprises a screening element, whose material and / or mesh opening differs from the metal gauze of the support screen. The screening element may be particularly engraved in this case. In a particularly advantageous configuration, the metal gauze of the support screen is a pure plastic fabric, while the screen element comprises a bronze screen, particularly an engraved bronze screen. For this reason, an engraving can easily be integrated into a metallic plastic gauze that cannot be recorded otherwise.

In the case of an equally advantageous variant of the invention, the insertion element comprises a type E or a watermark insert, particularly a tip E type or a multi-level watermark insert. Insertion elements of this type may be advantageously formed of steel. The insertion elements, for example of steel, can be joined by conventional techniques with no more than a conventional bronze metal gauze. The invention creates in this case an aid and allows to combine with each other the advantageous properties of a bronze and E type support screen or steel watermark inserts.

According to an equally advantageous variant of the invention, the insertion element comprises a pointed frame, for example a pointed steel frame, to generate a trade of sharp edges in the paper. In contrast to the usual procedures, a draining screen of this type allows sharp holes to be generated during papermaking. Therefore, not only is a separate work stage saved, such as a laser cutting or stamping stage, rounded edge holes can be combined due to common manufacturing but also with an exact record with other safety features of the manufacturing of paper, particularly with watermarks and / or holes with characteristic irregularities in the border area.

In advantageous configurations the insertion element comprises a metal insert and / or a plastic insert, particularly water-resistant plastic. A plastic insert of hydrophobic plastic can be arranged for example inside a sharp steel frame mentioned above, to encourage the formation of holes.

Depending on the desired design, it may be appropriate when the metal plate, or the plastic plate, is provided with multiple perforations, the dimensions of which are preferably so small that, during papermaking, no fiber is adhered to them. For example, an area of diluted paper with a reduced perforation density can be generated through a bronze insert. The metal or plastic insert can also be unperforated when, for example, the formation of holes must be facilitated.

The support screen of the draining screen can also include a magnet element with which during the formation of sheets magnetic fibers and / or magnetic additives can influence the pulp. For example, the magnetic fibers can be oriented along the magnetic field lines of the magnet element and fixed during drying in their directed orientation to create a safety feature in the form of a partial magnetic zone on the paper. The magnet element can also lead to a channeled accumulation or impoverishment of magnetic additives in certain areas of paper.

The magnet element can in this case be advantageously included in the insertion element, for example in the form of a permanent perforated magnet. Alternatively or additionally the magnet element may also be formed by magnetic additives in the plastic injection molding around or the rear plastic injection molding. The magnet element may also be arranged in injected threads. Finally, it is also possible to integrate the magnet element not into the upper sieve layer of the support screen but to place it, for example, within the round screen. It is only essential that the magnetic field of the magnet element in the area of the first sieve layer be of sufficient thickness to influence the magnetic fibers or the magnetic additives of the pulp during sheet formation.

According to a refinement of the invention, the plastic injection molding around or the plastic injection molding behind has a surface relief to generate a watermark of two or several levels on the paper. Since the injection molding around or rear injection molding generally circulates around the insertion element the safety features generated by the insertion element itself can therefore be combined with an additional safety feature in the form of a watermark of Two or multi level.

In all configurations, the plastic injection molding around or the plastic injection molding behind can be provided with multiple perforations, the dimensions of which are preferably so small that no fiber adheres to them during papermaking.

The insertion zone may be formed in particular by a partially cut area of the metal gauze.

Advantageously, two or more of the described configurations can be combined into an insertion element to generate several security features simultaneously, in very good registration or even in perfect registration with each other during papermaking.

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The invention also includes a process for the manufacture of a draining screen for the manufacture of paper, in which

- a support screen is prepared, which includes a metal gauze with an insertion zone,

- an insertion element is provided in the metal chiffon insertion zone to generate at least one safety feature on the paper, and

- the insertion element is molded by plastic injection around or molded by rear injection to join the insertion element with the support screen.

Preferably in the process, the surrounding plastic injection molding, or the rear plastic injection molding, is provided with multiple perforations whose dimensions are so small that no fiber adheres to them during papermaking. The perforations can be generated in this case by laser beam, preferably by infrared laser.

Finally, the invention also includes a process for the manufacture of a paper with at least one safety feature, in which the accumulation of paper is carried out on a drainer of the type described.

In a variant of an advantageous procedure as a safety feature, a hole with sharp edges is generated in the paper. After another variant of the procedure which is also advantageous, a hole with characteristic irregularities in the edge area and / or a watermark on the paper is generated as a safety feature. A procedural path offers spatial advantages in which as a first security feature a sharp edge hole is generated in the paper and in which as a second security feature a hole with characteristic irregularities is generated in the edge area and / or a mark of water on the paper, the first and second security features being registered in relation to each other. Configurations of this type are visually appealing by combining different security features and offer high security against counterfeiting.

Examples of embodiment as well as additional advantages of the invention, in which the representation in a reproduction faithful to the scale and proportional to increase clarity has been renounced, are explained below by means of the figures.

They show:

Fig. 1 a schematic representation of a ticket with a complex combination of several security features,

Fig. 2 in (a) schematically a cross-section through a basic form of a draining screen according to the invention, and in (b) a variation of the basic form of (a),

Fig. 3 a support screen with an integrated insertion element according to an embodiment of the invention,

Fig. 4 a support screen with an integrated insertion element according to another example of embodiment of the invention,

Fig. 5 a support screen with an integrated insertion element according to another example of embodiment of the invention,

Fig. 6 an example of a complex embodiment, with an insert for the simultaneous generation of several safety features, in which it shows (a) a cross section and (b) a plan view of the draining screen, and (c ) the visual appearance of the paper formed,

Fig. 7 a draining screen with an integrated magnetic insertion element, and

Fig. 8 the appearance of a paper generated with the draining screen of Fig. 7.

The invention is now explained in the example of banknote security features. Fig. 1 shows a schematic representation of a bill 10 with a complex combination 12 of several security features. The banknote 10 includes a hole 16 of fine structure with edge of sharp limits in the form of a rider, which is formed by a very thin area of paper 15 and is surrounded by a high resolution frame 14 watermark. The fine structure hole 16, the thin paper area 15 and the frame watermark 14 have very low registration tolerances due to the technology of injection molding around or rear injection molding.

Such complex combinations of safety features 14, 15, 16 can be generated with conventional procedures not already during papermaking. Particularly the generation of a hole with edge of

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Sharp boundaries and fine contour structure, such as hole 16 in Fig. 1, require a separate work stage by laser cutting or stamping. In this case, relatively high registration tolerances generally occur between the hole generated by laser stamping or cutting and a watermark generated during papermaking. These registration tolerances considerably limit the watermark / hole designs that can be used in practice since the designer must consider the registration tolerances already during the design of the configuration.

In accordance with the invention, the security paper of the banknote 10 is manufactured using a draining screen that will be described in more detail below, whereby both the fine-structured hole 16 as well as the thin paper area 15 and the High resolution 14 frame watermark can be generated already during papermaking and in a perfect record with respect to each other.

With reference to Fig. 2 (a), which schematically shows a cross section through a basic form of a draining screen according to the invention, the draining screen 20 comprises a support screen 22 with a metal gauze 24, which it is trimmed in a partial zone 30. The metallic gauze 24 has at least one system respectively of warp threads 26 interwoven with each other, which run in the longitudinal direction and weft threads 28 that run perpendicular to them. Within the scope of the present invention, metallic gauze may include, for example, a metal cloth, particularly a bronze cloth, a mixed metal-plastic fabric, particularly a mixed bronze-plastic fabric or also a pure plastic fabric. The support screen 22 may include a single-layer or multi-layer metal gauze, shown in the figures in each for a more simplified representation of only a single-layer metal gauze.

In the cut-out partial zone 30 of the metal gauze 24 an insertion element 32 is arranged to generate at least one safety feature 14,15,16 in the security paper, the insertion element 32 being joined by an extrusion coating of plastic 34 with the support screen 22. Fig. 2 (b) shows a variation of the basic form of Fig. 2 (a), in which the insert 32 is connected by a rear plastic injection molding 36 with the support screen 22. By means of the plastic injection molds around 34 according to the invention 34 or injection molds 36 multiple different insertion elements 32 can be integrated into the support screen 22, particularly also those insertion elements 32 , which cannot be integrated with conventional techniques due to the variety of materials or due to a special form or other special properties of the insert 32 in the support screen 22.

In some configurations it is suitable when the insertion element 32, the plastic injection molding around 34 or the rear plastic injection molding 36, or also both elements are provided with perforations to guarantee the runoff during papermaking in these areas . The dimensions of the perforations are selected in this case so small that no fiber adheres to them during papermaking.

In additional configurations the metal gauze 24 is not trimmed, but only has an area and insert in which the insertion element is arranged. Particularly the metal gauze during the injection molding around can continue to run behind the insertion element and during the rear injection molding at or behind the rear injection molding.

The following figures show some concrete realization examples for insertion elements, which cannot be integrated without more with usual procedures in the integrated support screen.

In the exemplary embodiment of Fig. 3, the support screen 40 has a bronze metal gauze 42. In the cut-out partial area 30 of the bronze metal gauze 42, an insert 44 is provided that includes a steel insert 46 with a type E of steel 48 that ends in tip. The insertion element 44 is connected by a plastic extrusion coating 34 with the support screen 40.

A steel insert 44 with a type E of steel 48 that ends in a point due to the variety of materials cannot be soldered in a bronze metallic gauze 42. A weld joint fails due to the type E 48 that ends pointed at the variety of surfaces to be joined. Although a welding joint of the steel insertion element 44 with the bronze metal gauze 42 is essentially not possible, however fine welds decompose in an acidic environment of the paper pulp and there is also a danger that the meshes of the Metal gauze 42 is closed by brazing paste.

The same problems appear in general in the case of steel types E that are narrowed upwards, such as for example types E of various type levels, or also in the case of multi-level steel watermark inserts that cannot be joined no more with conventional procedures with bronze metal gauze 42, but which can be integrated by a plastic injection molding around 34 or a rear plastic injection molding 36 without problems in the support screen.

Fig. 4 shows an example of a further embodiment in which the support screen 40 also has a bronze metal gauze 42. In an partially cut-off area 30 of the bronze metal gauze 42, an insertion element 50 is provided that includes a pointed steel frame 52. With the pointed steel frame 52, a hole 16 with a sharp edge is already generated during papermaking, as for example illustrated in Fig. 1. He

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insertion element 50 with the steel frame 52 is joined by an extrusion coating of plastic 34 with the support screen 40. On the contrary with usual procedures the steel frame 52, for the reasons mentioned above cannot be integrated into the screen 40 bronze support.

To reinforce the effect, the insertion element within the steel frame may additionally include a plastic insert 54 of a hydrophobic plastic. Such a measure is particularly suitable then when only smaller holes are generated with the steel frame 52.

In the case of the embodiment of Fig. 5, the insertion element integrated in the support screen 60 is formed by a screen element 64 whose material and / or mesh opening differs from the metal gauze 62 of the screen support 60. For example, the support screen 60 may include a pure plastic metal gauze 62 and the screen element 64 may be formed by a bronze sieve with an engraving 66, which is joined by the plastic injection molding around 34 with the support screen 60. In this way, however, an engraving 66 can easily be integrated into a plastic metal gauze 62 which cannot be recorded by itself.

Fig. 6 shows an example of a complex embodiment in which the insertion element 72 of the draining screen 70 is designed for the simultaneous generation of several different safety features. Fig. 6 (a) shows in this case a cross section and Fig. 6 (b) a plan view of the draining screen 70. The visual aspect of the formed paper 90 is represented in Fig. 6 (c).

Referring first to Figures 6 (a) and (b) the draining screen 70, such as the draining screen 20 of Fig. 2, includes a support screen 22 with a bronze metal gauze 24 cut into a partial area 30. In the cut-out partial zone 30 an insertion element 72 is disposed that is connected by a plastic extrusion coating 80 with the support screen 22. The plastic injection molding around 80 has in this embodiment an embossing of surface 82 of several levels and is also provided, to ensure runoff during the formation of sheets with multiple perforations. Since the plastic injection molding around 80 runs around the insertion element 72 forms a perforated injection molding frame that during papermaking due to its multi-level surface relief 82 generates a frame watermark 94 of several levels in paper 90 covering the safety features generated by the insertion element, as shown in Fig. 6 (c).

The insertion element 72 itself includes a bronze sheet 74 perforated only sparingly which due to the low perforation density and its smooth surface during papermaking generates a very thin area of paper 96. Inside the bronze sheet 74, a pointed steel frame 76 is provided to generate a hole 98 with a sharp edge (Fig. 6 (c)). The steel frame 76 may be staggered downwards in this case so that it does not come into contact with the draining cylinder or the receiving cylinder.

Inside the steel frame 76 there is a small insert 78 of hydrophobic plastic that promotes the formation of holes. The connection between the bronze plate 74, the steel frame 76 and the plastic plate 78 can be carried out, for example, by gluing, welding, stapling or other usual procedure.

With reference to the representation of Fig. 6 (c) the paper 90 generated with the draining screen outside the frame watermark 94 shows a coating area 92 of normal paper thickness. The frame watermark 94 has a multi-level design whose appearance is given by the surface relief 82 of several levels of the plastic injection molding around 80. Within the frame watermark 94 is a coating area 96 of very small paper thickness that is generated by the bronze sheet 74 of poor perforation, and within this thin coating area 96 a sharp-edged hole 98 of fine structure in the form of a rider is arranged. According to the invention all these different safety elements are generated simultaneously during manufacturing. Its manufacture does not require any separate work stage, such as a laser cutting or stamping stage. In addition, the safety features, due to the common generation through the insertion element, are very well registered with respect to each other. In particular, there is no registration oscillation between the frame watermark 94 and the sharp edge hole 98 so that the two elements can be oriented relative to each other as desired.

By means of injection molding around or rear injection molding according to the invention of insertion elements, magnetic elements can also be integrated into a support screen. For the illustration, Fig. 7 shows a draining screen 100 with a support screen 22 with a cut-out metal gauze 24, in whose partial cut-out area a permanent magnet 102 in the form of a sickle that is provided with multiple perforations is arranged as insert 104. The perforated permanent magnet 102 is connected by a plastic extrusion coating 34 with the support screen 22.

The plurality of perforations 104 guarantees the runoff in the area of the permanent magnet 102. By means of the magnetic field of the permanent magnet 102 during the sheet formation, the magnetic components of the pulp are channeled. For example, the pulp may include magnetic fibers that, during sheet formation, are oriented along the magnetic field lines of the permanent magnet 102. During the drying of the paper web, the magnetic fibers are then fixed in their directed orientation.

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60

Fig. 8 shows a plan view of a paper 110 generated with the draining screen 100 of Fig. 7 with a magnetic safety feature. In a partial sickle-shaped area 112 that was during the generation of paper directly on the permanent magnet 102, the magnetic fibers included in the pulp were oriented while the magnetic fibers are presented without ordering in the surrounding paper area 114.

The different orientation of the magnetic fibers can be checked on the finished paper 110, for example, with a magnet sensor.

In other configurations, the partial zone 112 can also be visually differentiated from the surrounding area 114. For example, the pulp may contain magnetic, color or fluorescent additives that are attracted or repelled by the permanent magnet 102 so that the concentration of these additives in the partial zone 112 differs from the concentration in the surrounding area 114.

The magnetic elements do not have to be included in the insertion element 32, they can also be formed by magnetic additives in the plastic injection molding around 34 or the rear plastic injection molding 36. They also do not have to be integrated in the layer of top screen 24 of the support screen 22 but may also be arranged in a deeper screen layer or inside the round screen. They can also be found in injected threads, for example. The magnetic elements can be combined with all the configurations described above.

List of reference numbers

10 banknote

12 complex security feature

14 frame watermark

15 thin paper area

16 fine structure hole

20 drainer screen

22 support screen

24 metal gauze

26 warp threads

28 weft threads

30 cropped partial area

32 insertion element

34 plastic injection molding around

36 plastic rear injection molding

40 support screen

42 bronze metal gauze

44 insertion element

46 steel insert

48 type E steel

50 insertion element

52 pointed steel frame

54 plastic insert

60 support screen

62 metal gauze

64 screening element

66 engraving

70 drainer screen

72 insertion element

74 bronze sheet

76 pointed steel frame

78 insert

80 plastic injection mold around 82 surface relief

90 paper

92 coated area of plain paper thickness

94 frame watermark

96 thin paper area

98 sharp edge hole

100 drainer screen

102 permanent magnet

104 perforations

110 paper

112 sickle-shaped partial zone 114 surrounding paper zone

Claims (19)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 1. Drainer screen (20) for papermaking, with at least one safety feature, with - a support screen (22), which includes metal gauze (24) with an insertion zone, - an insertion element (32) arranged in the metal chiffon insertion zone to generate the at least one safety feature on the paper and - an injection molding around plastic (34) or rear plastic injection molding (36) of the insertion element (32), which joins the insertion element (32) with the support screen (22). 2. Drainer screen according to claim 1, characterized in that the metal gauze (24) of the support screen (22) and the insertion element (32) are composed of different materials, particularly because the metallic gauze and the element of Insertion are made up of different metals or because one of the support screen elements and insertion element is composed of metal and the other element is composed of plastic. 3. Drainer screen according to claim 1 or 2, characterized in that the insertion element (32) comprises a screening element (64), whose material and / or mesh opening differs from the metal gauze of the support screen . 4. Screen drainer according to claim 3, characterized in that the screen element (64) is engraved. 5. Drainer screen according to claim 3 or 4, characterized in that the metal gauze (24) of the support screen (22) is a pure plastic fabric and the screen element (64) comprises a bronze screen, particularly an engraved bronze sieve. 6. Drainer screen according to at least one of claims 1 to 5, characterized in that the insertion element (32) comprises a type E (48) or a watermark insert, particularly a type E that ends at a point or a multi-level watermark insert. 7. Drainer screen according to at least one of claims 1 to 6, characterized in that the insertion element (32) comprises a pointed frame (52) for generating a hole with sharp edges (16) in the paper. 8. Drainer screen according to at least one of claims 1 to 7, characterized in that the insert comprises a metal insert and / or a plastic insert (54), particularly water repellent plastic. 9. Drainer screen according to claim 8, characterized in that the metal plate and / or the plastic plate (54) are provided with multiple perforations, the dimensions of which are preferably so small that during papermaking it does not adhere to them no fiber 10. Drainer screen according to at least one of claims 1 to 9, characterized in that the support screen (22) includes a magnet element, preferably because the insert element (32), the plastic injection molding around ( 34) or the plastic rear injection molding (36) includes the magnet element or because the magnet element is arranged in injected threads. 11. Drainer screen according to at least one of claims 1 to 10, characterized in that the plastic injection molding around (34) or the rear plastic injection molding (36) has a surface relief (82) to generate a watermark of two or several levels on the paper. 12. Drainer screen according to at least one of claims 1 to 11, characterized in that the plastic injection molding around (34) or the rear plastic injection molding (36) is provided with multiple perforations, the dimensions of which are preferably so small that no fiber adheres to them during papermaking. 13. Drainer screen according to at least one of claims 1 to 12, characterized in that the insertion zone is a partial cut-out zone (30) of the metal gauze (24). 14. Procedure for the manufacture of a drainer screen (20) for the manufacture of paper in which - a support screen (22) is prepared, which includes metal gauze (24) with an insertion zone, - an insertion element (32) is arranged in the metal chiffon insertion zone to generate at least one safety feature on the paper and - the insertion element (32) is molded by injection around or molded by rear plastic injection to join the insertion element with the support screen (22). 15. Method according to claim 14, characterized in that the plastic injection molding around (34) or the rear plastic injection molding (36) is provided with multiple perforations whose dimensions are so small that during the manufacture of paper no No fiber adheres to them. 16. Method according to claim 15, characterized in that the perforations are generated by laser beam, preferably by infrared laser. 17. Procedure for the manufacture of a paper with at least one safety feature, in which the accumulation of paper is carried out on a drainer according to one of claims 1 to 13. 5 18. Procedure according to claim 17, in which a security feature generates a Sharp edge hole (16) in the paper. 19. Method according to claim 17, wherein as a safety feature a hole (16) is generated with characteristic irregularities in the edge area and / or a watermark on the paper. 20. Method according to claim 17, in which a hole with sharp edges is generated in the paper as the first security feature and as a second security feature a hole is generated with characteristic irregularities in the edge area and / or a watermark on the paper, in which the first and second security features are registered with respect to each other.