CN112888573A

CN112888573A - Method and device for producing security paper with windowed security thread

Info

Publication number: CN112888573A
Application number: CN201980066025.2A
Authority: CN
Inventors: A.埃格纳; A.哈内尔特; A.坦特施尔; A.德雷克斯勒; M.普勒格
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient GmbH
Priority date: 2018-10-16
Filing date: 2019-10-15
Publication date: 2021-06-01
Anticipated expiration: 2039-10-15
Also published as: DE102018008162A8; DE102018008162A1; WO2020078579A1; CN112888573B; RU2769234C1; EP3867078A1

Abstract

The invention relates to a cylinder screen (12) of a cylinder paper machine (10) for producing security papers (42A, 42B) having partially embedded security threads (22), wherein during the production of the paper, the cylinder screen is used for producing security papersThe screen (12) draws stock in the form of a fibre-water-suspension (14) from the pulp basin (16), and wherein the cylindrical screen (12) comprises a manufacturing screen (30) having a circumferential direction (U) and a transverse direction (Q) perpendicular to the circumferential direction, which manufacturing screen is provided with a plurality of protruding thread window elements (34) along the circumferential direction (U) on which the windowed thread (22) is placed during the papermaking process in order to locally inhibit the accumulation of the fibre-water-suspension (14) so as to produce thread windows (40). According to the invention, the wire window element (34) is arranged with an offset (36) in the transverse direction (Q), which is periodic in the circumferential direction, wherein the circumference R of the cylindrical screen is_UIs an integer multiple of the offset period P. The invention also relates to a corresponding method for producing security paper.

Description

Method and device for producing security paper with windowed security thread

The present invention relates to a method and apparatus for making security paper having windowed security threads (or security threads).

In order to provide security, security papers or value documents are often provided with authenticity features, such as watermarks, embedded security threads, etc., which allow the authenticity of the security paper or value document to be checked or at the same time serve as protection against unauthorized copying.

In the past, authenticity features which can only be introduced into security papers during manufacture have proven themselves here, such as security threads which are completely or partially embedded in the security paper. Security threads which are neither completely applied to the surface of the security paper nor completely embedded in the security paper are referred to herein as windowed security threads. These windowed security threads are partially embedded in the security paper in such a way that they are visible only in certain windowed areas (also referred to below as windows) on one or both of the opposite surfaces of the security paper.

In bronze screens, such wire windows are usually produced by means of raised (or embossed) ribs. These ribs are typically rectangular high-pressure embossments (or raised embossments) in the form of plateaus. The width of the plateau serves as a so-called wobble area of the security thread, the width of which is related to the width of the thread. In the paper production process, the threads are brought onto a cylindrical screen with high embossing (or cylindrical wire) and are laid back and forth on the high embossing, so that the laid threads are not laid exactly on top of one another in the paper stack, but rather a distribution of the threads with respect to both sides is achieved. This so-called line swinging is essential in order to ensure a sufficiently good flatness of the sheets (or large sheets) and the sheet bundle so that they can be handled at the crosscutting machine, at printing, at copy cutting and at bundling.

However, if non-rectangular window shapes are used, line wiggling often results in poor flatness and an extremely different and not well defined window arrangement. Furthermore, to supplement reasonably, the wobbling area needs to be considered when designing the pattern, which results in a large limitation on pattern discovery.

Starting from this, the object of the invention is to avoid the disadvantages of the prior art and in particular to provide a method and a device for producing security papers with windowed security threads, by means of which non-rectangular thread windows, in particular in the form of patterns, can also be used advantageously.

The object is achieved by the features of the independent claims. The invention is characterized in that it is provided with a plurality of design elements.

The invention provides a cylinder screen of a cylinder paper machine for producing security paper with partially embedded windowed security threads, wherein the cylinder screen draws paper stock in the form of a fiber-water-suspension from a pulp basin during the paper making process. The cylindrical screen comprises a manufacturing screen having a circumferential direction and a transverse direction perpendicular to the circumferential direction, which manufacturing screen is provided with a plurality of raised thread window elements on which the windowed thread-preventing threads are placed during the papermaking process in order to locally suppress the accumulation of the fiber-water-suspension for the production of thread windows. In this context, provision is made according to the invention forThe wire window elements are arranged with a lateral offset (or with a lateral offset) which is periodic in the circumferential direction, wherein the circumference R of the cylindrical screen is_UIs an integer multiple of the offset period P.

Here, the circumference R of the cylindrical screen_UPreferably equal to the offset period P or equal to twice the offset period P. In principle, it is also possible for the ratio R of the circumference of the cylindrical screen to the offset period_Uthe/P is 3 or more, but in the case of larger ratios, correct wire guidance is technically more complex, so the smaller ratios 1, 2 or 3 mentioned are currently preferred. The ratio is particularly advantageously 1, i.e. the circumference R of the cylindrical screen_UEqual to the offset period P.

In an advantageous embodiment of the invention, at least one line window element is provided for each copy (Nutzen) provided on the production sleeve. The line window element may also be combined with further screen elements, such as conventional watermark embossing, watermark embedding or E-type (E-type).

In an advantageous embodiment, at least some of the further screen elements have the same periodic offset as the line window elements and are therefore always arranged on the security paper in a manner matched to the line window elements. Such an arrangement is particularly advantageous in the case that these screen elements are arranged directly adjacent to the thread window elements or the windowing security thread and/or are associated with the thread window elements in a sense and for example represent information relating to or complementing the thread window elements.

In a further, likewise advantageous embodiment, at least some of the further screen elements are arranged without offset and therefore matched to the outer contour of the cut security paper. Such an arrangement is particularly advantageous in cases where these screen elements are arranged at a significant distance, for example at a distance of a few centimeters, from the thread window element and the fenestration security thread, and/or where further screen elements are not associated in a sense with the thread window element.

The wire window element may be at least partially formed by high pressure embossing in the manufacturing web. Alternatively or additionally, the line window element may be formed at least partially by a watermark insert, in particular an injection-molded (or injection-molded) watermark insert. Such watermark inlays for making high resolution watermarks are for example described in more detail in patent documents EP 2895310 a1 and EP 2899312 a1, the disclosures of which are incorporated in the present application within this scope.

The line window element is preferably designed to be non-rectangular, in particular in the form of a pattern (or visual object).

In an advantageous embodiment, the accumulation of the fiber-water suspension is not completely suppressed in all regions, but is only partially suppressed in some local regions. In this case, during the paper making process, the thread window element produces a watermark in which the security thread extends on the surface of the paper in some partial areas, i.e. in partial areas where the fibre accumulation is completely suppressed, and in other partial areas in the interior of the paper. Particularly advantageously, the wire window element comprises at least one partial region in which the accumulation of the fiber-water suspension is completely suppressed and at least one partial region in which the accumulation of the fiber-water suspension is only partially suppressed.

The line window elements are advantageously arranged circumferentially with a sinusoidal or triangular offset.

The invention also comprises a method for producing a security paper for producing security documents, such as banknotes, identity cards and the like, having a windowed security thread which is embedded in the security paper and is guided onto at least one surface of the security paper at least one opening in the security paper, wherein a cylindrical screen of a cylinder paper machine draws a paper stock in the form of a fiber-water-suspension from a pulp bath, and wherein the cylindrical screen comprises a production screen having a circumferential direction and a transverse direction perpendicular to the circumferential direction, which production screen is provided with a plurality of raised thread window elements in the circumferential direction on which the security thread to be embedded is placed during the paper production process in order to locally suppress the accumulation of the fiber-water-suspension for producing the thread windows. According to the invention, the wire window element is arranged to have a transverse directionAn offset which is periodic in the circumferential direction, wherein the circumference R of the cylindrical screen_UIs an integer multiple of the offset period P.

In this case, the thread to be embedded is advantageously moved back and forth in the transverse direction of the cylindrical screen synchronously with the rotation of the cylindrical screen.

Preferably, the thread to be embedded is reciprocated n times in the transverse direction of the cylindrical screen per revolution of the cylindrical screen, wherein n ═ R_Uand/P, n represents the integer ratio of the circumference of the cylindrical screen to the offset period. As already mentioned above, n is in particular equal to 3, 2 or, particularly preferably, equal to 1.

Particularly preferably, a cylindrical screen of the type described above is used in the process.

Further embodiments and advantages of the invention are described below with reference to the accompanying drawings, which are not shown true to scale for clarity.

In the drawings:

FIG. 1 schematically illustrates a cylinder mould machine according to an embodiment of the present invention;

FIG. 2 schematically illustrates a portion of the cylindrical screen of FIG. 1 making a mesh sleeve;

FIG. 3 shows in (a) and (b) two security paper copies made with the cylindrical screens of FIGS. 1 and 2 having different thread window horizontal positions and correspondingly different windowed security thread horizontal positions;

fig. 4 schematically shows the improved flatness of a plurality of stacked sheets by line swinging and window swinging;

FIG. 5 shows a security paper having a slanted line window according to a further embodiment of the invention; and

fig. 6 shows a security paper with a line window in the form of a watermark.

The invention is described here by way of example for the production of security papers for banknotes with security threads with fenestration. To this end, fig. 1 schematically shows a cylinder papermaking machine 10 having a cylindrical screen 12, which cylindrical screen 12 is immersed in a fiber-water-suspension 14 in a pulp bath 16. The continuous security thread 22 is embedded in the paper web 20 as a windowed security thread during the paper forming process. To this end, the security thread 22 is moved onto the projections 18 of the cylindrical screen 12 before being immersed in the fiber-water suspension 14.

In the paper web 20 so produced, the security thread 22 lies substantially in the inner plane of the paper, but no paper fibers of the fiber-water-suspension 14 accumulate at the contact surface of the security thread 22 with the projections 18, so that windows are created there where the security thread 22 emerges at the surface of the paper.

To ensure that the laid threads do not then exactly overlap one another in the paper stack, the security threads 22 to be embedded are reciprocated in the transverse direction of the cylindrical screen, which is perpendicular to the paper plane in fig. 1, during the paper making process.

As mentioned above, the security thread is usually moved back and forth on a rectangular projection in the process, so that the width of the projection forms a so-called wobble zone for the security thread.

However, in order to also be able to use wire windows with complex shapes, according to the invention the projections 18 are constituted by projecting wire window elements 34 which are arranged along the circumferential direction of the cylindrical screen 12 with a periodic offset in the transverse direction Q of the cylindrical screen.

Explaining this principle according to fig. 2, fig. 2 schematically shows a part of the cylindrical screen 12 in the circumferential direction U and the transverse direction Q of the cylindrical screen for making the mesh 30. The location of the multiple banknote copies 32 is shown in phantom. Of course, the actual manufacturing web 30 contains a much larger number of copies in the circumferential direction, and the offset of the wire window elements 34 is typically smaller than shown here in practice.

In this case, a plurality of projecting thread window elements 34 are arranged in each case along the circumferential direction U of the production fleece 30, on which thread window elements the security thread 22 rests during the paper production process. According to the invention, the wire window elements 34 are arranged with an offset in the transverse direction Q which is periodic in the circumferential direction U, wherein the circumference R of the cylindrical screen is_UIs an integer multiple of the offset period P, i.e. R_UN is a natural number, in particular n is 1, 2 or 3.

In the exemplary embodiment of fig. 2, a particularly preferred case of n ═ 1 and a sinusoidal offset 36 are shown, wherein the offset period P is exactly equal to the circumference R of the cylindrical screen_U. Offset scrollThe degree A may be, for example, 15 mm. In this way, multiple line windows 40 (see fig. 3) are not produced at the same horizontal position within the copy 32, but rather the positions of these line windows are wobbled back and forth with an offset period P and amplitude a.

At this time, in the paper making process, the movement of the wire drive rod for generating the wire sweep is synchronized with the rotation of the cylindrical screen 12, and the starting point (Einsatzpunkt) and the frequency are selected so that the security wire 22 is accurately positioned on the wire window element 34 at the time of embedding. In the case where n ═ 1 shown here, the thread 22 oscillates back and forth exactly once per revolution of the cylindrical screen in the transverse direction of the cylindrical screen. Of course, in the general case, for each revolution of the cylindrical screen, there is a reciprocal movement n times in the transverse direction of the cylindrical screen of the security thread to be embedded, where n is R_Uand/P, n is the integral ratio of the circumference of the cylindrical screen to the offset period.

The effect of this synchronized line and window oscillation is shown in fig. 3, and fig. 3 shows in (a) and (B) two

copies

42A, 42B of security paper produced with the cylinder screen of fig. 1 and 2, which copies have a horizontal position F of the line window 40_A、F_BAnd they have correspondingly different horizontal positions of the windowed thread 22. Since the line wiggling is synchronized with the offset period P of the line window element 34, the windowed thread 22 in

copies

42A, 42B is located at the same position in the line window 40 even if the position of the line window 40 is changed in common with the line 22 in the copies.

The exact orientation of the registration of the line window 40 and the line 22 is significantly more noticeable and important to the viewer than small differences in the relative position of the line window 40 between the

different copies

42A, 42B.

In addition to the line window 40, the

security paper copy

42A, 42B of fig. 3 has two

further watermarks

44, 46, respectively, which have different relative orientations with respect to the line window 40 or with respect to the edge 48 of the copy. The watermark 44 disposed in the immediate vicinity of the embedded security thread 22 has the same periodic offset as the thread window element 40. Thus, despite the line wiggling, the relative positions of the line window 40, security line 22, and watermark 44 are the same in the

copies

42A, 42B, and the appearance of the watermark 44 is not altered or affected by the line wiggling. The watermark 44 and the line window 40 may also be related in meaning and may for example represent information that complements or is related to each other, since their common appearance is the same in all

copies

42A, 42B.

On the other hand, watermark 46 is remote from line window 40 and security line 22 and is not otherwise affected by line wiggling. Furthermore, the position of the watermark 46 relative to the adjacent edges 48 of the

copies

42A, 42B is much more noticeable to a viewer than the position relative to the security thread 22 and the thread window 40. The watermark 46 is thus arranged in all security paper copies without offset at the same position relative to the copy edge 48.

Fig. 4 schematically illustrates the improved flatness of the plurality of stacked sheets 50 by the line swing and the window swing. For illustration, a design is shown in which the circumference R of a cylindrical screen is_UEqual to the shift period P, and in which two sheets are arranged in sequence in the circumferential direction of the cylindrical screen. In practice, however, usually more, for example 4, 5, 6, 8 or 10, sheets of paper are arranged one after the other in the circumferential direction of the cylindrical screen.

The sinusoidal offsets of the lines 22 and the associated windows 40 are drawn schematically for two sheets of paper lying one on top of the other, these offsets being drawn with solid lines for the first sheet (offset 52) and with dashed lines for the second sheet (offset 54). The positions shown are repeated for additional sheets of paper positioned above it. Also shown is the offset amplitude a. It can be clearly seen how the wire 22 and the window 40 are laid side by swinging. The thickening when stacking a plurality of sheets occurs only in the intersection region 56, but the intersection region can be kept very short. Since in this embodiment two sheets of paper are arranged in succession in the circumferential direction of the cylindrical screen, the thread windows 40 and the security threads 22 have exactly half the period of the sinusoidal offset in each sheet of paper. If, in practice, for example, six sheets of paper are arranged one after the other in the circumferential direction of the cylindrical screen, the thread windows and the security threads in each sheet of paper exhibit exactly one sixth of the sinusoidal offset period. In this case, the position of the thread 22 and the window 40 overlapping each other is repeated only once every six sheets.

Fig. 5 shows a further embodiment in which the security paper 60 is provided with an inclined line window 62. In the conventional case, a windowed thread 22, as a result of pivoting in a fixed window 62, can occupy any position between the left window edge 64 and the right window edge 66 and therefore in the vicinity of the edge positions 64, 66, have an excessively small distance from the upper or lower banknote edge 68.

In contrast, the synchronization according to the invention of the thread and window pivoting ensures that the thread 22 is always located in the middle of the window 62 and therefore at a sufficient distance from the banknote edge 68, regardless of its specific horizontal position on the security paper 60.

In the embodiment of fig. 6, the thread window of the security paper 70 is designed in the form of a watermark 72, wherein the embedded security thread 22 extends in some partial areas over the surface of the paper 70, while the security thread is embedded in other partial areas inside the paper.

It is generally considered in these designs that the position of the security thread 22 within the wobble zone W fluctuates and therefore the resulting combination of thread position and watermark pattern is different and partially unusable. According to the present invention, the position of the watermark 72 as a line window is changed in the same manner as the line wobble, thus producing synchronization of the line wobble and the window wobble. This ensures that the security thread 22 is always in the desired position relative to the pattern of the watermark 72, regardless of its specific vertical position on the security paper 70. Specifically, the security thread 22 of FIG. 6 always passes through the sail of the boat pattern 72 at the same height H due to the synchronized thread and window flapping.

Of course, the wire window element 34 described may have a variety of different shapes. The thread window element 34 can in particular be formed both by an embossing in the production of the mesh and by a watermark insert arranged in the mesh. The security thread 22 can be narrower than the thread window element 34, the same width as the thread window element or wider than the thread window element, wherein in the last case the shape of the element 34 can be printed on the thread.

List of reference numerals

10 cylinder mould paper machine

12 cylinder screen

14 Water fiber suspension

16 paper pulp tank

18 projection

20 paper web

22 security thread

30 manufacturing the net cover

32 banknote copy

34-line window element

36 offset

40 line window

42A, 42B copy of security paper

44 watermarking

46 watermark

50 paper

52. 54 offset

56 intersection region

60 anti-counterfeiting paper

62 inclined line window

64. 66 window edge

68 banknote edge

70 anti-counterfeiting paper

72-line window-watermark

U circumference direction

Transverse direction of Q cylinder screen

F_A、F_BPosition of wire window

Height H

Claims

1. A cylinder screen of a cylinder mould paper machine for the production of security paper with partially embedded security threads, wherein the cylinder screen draws stock in the form of a fibre-water-suspension from a pulp basin during the paper production process, and wherein the cylinder screen comprises a production screen jacket with a circumferential direction and a transverse direction perpendicular thereto, which production screen jacket is provided with a plurality of raised thread window elements in the circumferential direction on which the security threads are placed during the paper production process in order to locally inhibit the accumulation of the fibre-water-suspension and thus to produce the thread windows,

it is characterized in that the preparation method is characterized in that,

the wire window elements are arranged with an offset in the transverse direction, which offset is periodic in the circumferential direction, wherein the circumference R of the cylindrical screen is_UIs an integer multiple of the offset period P.

2. The cylindrical screen of claim 1, wherein the cylindrical screen has a circumference R_UEqual to the offset period P or equal to twice the offset period P.

3. The cylindrical screen of claim 1 or 2, wherein at least one wire window element is provided for each copy provided on the manufacturing sleeve.

4. The cylindrical screen according to at least one of claims 1 to 3, characterised in that the wire window elements are at least partially constituted by high pressure threads in the manufacturing of the mesh.

5. The cylindrical screen according to at least one of claims 1 to 4, characterized in that the wire window element is at least partially formed by a watermark insert, in particular an injection-molded watermark insert.

6. The cylindrical screen panel as claimed in at least one of claims 1 to 5, characterized in that the wire window elements are designed to be non-rectangular, in particular in the form of a pattern.

7. The cylindrical screen according to at least one of claims 1 to 6, characterized in that the wire window elements are arranged circumferentially with a sinusoidal or triangular offset.

8. The cylindrical screen panel according to at least one of claims 1 to 7, characterised in that the wire window elements are combined with further screen elements, in particular watermark embossing, watermark embedding or E-type.

9. The cylindrical screen of claim 8, wherein at least some of the additional screen elements are arranged on the fabrication sleeve with the same periodic lateral offset as the wire window elements.

10. The cylindrical screen of claim 8 or 9, wherein at least some of the further screen elements are arranged on the manufacturing sleeve without an offset in the transverse direction.

11. A method for producing security papers, for example banknotes, identity cards or the like, which have a windowed security thread which is embedded in the security paper and is guided onto at least one surface of the security paper at least one opening in the security paper, wherein a cylindrical screen of a cylinder paper machine draws stock in the form of a fiber-water-suspension from a pulp bath, and wherein the cylindrical screen comprises a production mat having a circumferential direction and a transverse direction perpendicular to the circumferential direction, which production mat is provided with a plurality of raised thread-window elements in the circumferential direction, on which thread-window elements the security thread to be embedded is placed during the paper production process in order to locally suppress the accumulation of the fiber-water-suspension so as to produce thread windows,

it is characterized in that the preparation method is characterized in that,

12. The method according to claim 11, wherein the thread to be embedded is reciprocated in the transverse direction of the cylindrical screen in synchronism with the rotation of the cylindrical screen.

13. The method of claim 12, wherein the security thread to be embedded is caused to follow the cylinder with each revolution of the cylinder screenThe screen is transversely reciprocated for n times, wherein n ═ R_Uand/P, n represents the integer ratio of the circumference of the cylindrical screen to the offset period.

14. Method according to any one of claims 11 to 13, characterized in that a cylindrical screen according to any one of claims 1 to 10 is used.