EP2764159B1 - Method and device for the production of a sheet-type substrate - Google Patents

Description

The present invention relates to a method and an apparatus for producing a sheet-like substrate with a security thread, in particular a banknote paper with a security thread.

In order to detect the elongation of a security thread embedded in a banknote paper, for example, strain-sensitive magnetic features integrated in the security thread are detected with a sensor arranged after a dryer section of the paper machine for producing the banknote paper.

Such a magnetic measurement is very distance sensitive and therefore difficult to perform.

Based on this, it is an object of the invention to provide an improved method for producing a sheet-shaped substrate with a security thread. Furthermore, an improved device for producing a sheet-shaped substrate with a security thread is to be provided.

1. a) ein Sicherheitsfaden mit in Längsrichtung des Sicherheitsfadens voneinander beabstandeten Merkmalen in das Substrat so eingeführt wird, dass er zumindest teilweise im Substrat eingebettet ist,
2. b) zumindest eines der Merkmale nach dem Einbetten des Sicherheitsfadens als Bild abgebildet wird,
3. c) anhand des Bildes des zumindest einen Merkmales die Dehnung des eingebetteten Sicherheitsfadens in Längsrichtung ermittelt wird, und
4. d) in Abhängigkeit der ermittelten Dehnung der Bereich des Substrates entwertet wird, in dem die ermittelte Dehnung des Sicherheitsfadens eine vorgegebene maximale Dehnung übersteigt.

According to the invention the object is achieved by a method for producing a sheet-shaped substrate with a security thread, in particular a banknote paper with a security thread, in which

1. a) a security thread is inserted in the longitudinal direction of the security thread spaced apart features in the substrate so that it is at least partially embedded in the substrate,
2. b) at least one of the features after embedding the security thread is imaged as an image,
3. c) the elongation of the embedded security thread in the longitudinal direction is determined on the basis of the image of the at least one feature, and
4. d) depending on the determined elongation, the region of the substrate is devalued, in which the determined elongation of the security thread exceeds a predetermined maximum elongation.

By imaging the at least one feature as an image, the strong distance dependence between the sheet-shaped substrate and the sensor is no longer present, as in the case of the magnetic markings. It is only important that an image of the feature is obtained with such a resolution that allows a determination of the elongation of the embedded security thread based on the image.

By the good and accurate detection of the elongation of the security thread and the corresponding devaluation when exceeding the intended maximum elongation can be ensured that the not devalued sheet-like substrate contains no overstretched security thread. Thus, with the method according to the invention, sheet-shaped substrate can be produced with an extremely low error proportion with regard to the thread overstretching. The method of the invention provides extremely safe and good reject detection and depreciation.

To carry out step d), the region of the substrate in which the determined elongation of the security thread exceeds the predetermined maximum elongation can be marked, for example with a reject mark. All marked areas or areas marked with a reject mark are considered invalidated and can, for example, be taken later (eg on the cross cutter).

In step a), in particular, an aqueous fiber mass which contains a mixture of water and fibers can be deposited on a carrier surface and the security thread can be embedded in the deposited fiber mass under tension or under tension.

Furthermore, in the method according to the invention in step c), the distance between two features in the longitudinal direction can be evaluated to determine the elongation. For this purpose, in step b), the images of preferably at least two features are recorded in a common recording. This can be realized by taking a picture with an image sensor in which the at least two features are contained.

Additionally or alternatively, in step c) at least one dimension of the at least one feature (eg the extent of the at least one feature in the longitudinal direction of the security thread) can be evaluated to determine the elongation. Additionally or alternatively, the extension of the feature transverse to the longitudinal direction can be evaluated to determine the thread elongation.

In particular, in step c) a pattern comparison between the at least one recorded feature and a stored target image of the feature can be performed. Such pattern matching can be performed automatically with high accuracy. In particular, in such a pattern comparison, the distortions of the recorded feature due to the elongation of the security thread can be taken into account.

The features may be a so-called clear text (recesses in the form of a number, letter and / or string in an opaque coating). Alternatively, the features may also be present in the form of a so-called positive text (opaque coating in the form of a number, letter and / or string in a transparent environment) or a combination of both. The features may also include or represent geometric patterns. Thus, the feature z. B. have a square or rectangular shape. In particular, the features may be those features which already serve on the security thread for checking the authenticity of the sheet-shaped substrate in which the security thread is embedded. Thus, no additional features need to be provided which only serve to check the thread elongation in the production of the sheet-shaped substrate.

Preferably, the features are formed longitudinally on the security thread in the longitudinal direction.

In the method according to the invention, depending on the elongation determined in step c), the step a) of the embedding of the security thread can be controlled in order to prevent exceeding the predetermined maximum elongation of the security thread.

In the method of the present invention, the sheet-shaped substrate with the embedded security thread can be produced in a moving screen papermaking machine, wherein the step b) is performed immediately after the substrate is taken off the wire. Thus, the still moist or wet substrate is checked immediately after its preparation with respect to the elongation of the security thread, so that, if one Overstretching of the security thread is present, the Committee can be minimized.

Alternatively, in the method of the present invention, the sheet-shaped substrate having the embedded security thread can be produced in a moving screen papermaking machine, wherein step b) is performed at the end of the papermaking machine. In particular, step b) may be carried out after a drying section of the papermaking machine or shortly before the sheet-like substrate is rolled up.

In step b) the recording can be carried out in transmitted light or incident light. In particular, the recording can be carried out with light from the visible wavelength range, IR radiation and / or UV radiation.

In the method according to the invention, the mechanical tension of the security thread during embedding in step a) can be controlled in step d) so that overstretching of the embedded thread is prevented as far as possible.

The security thread can also be designed as a security foil or as another elongated security element. Preferably, the security element has the features in the longitudinal direction spaced from each other periodically.

The sheet-shaped substrate with the at least partially embedded security thread produced by the method according to the invention can also be referred to as security paper and for the production of value documents, such. B. banknotes serve.

The security thread may have a width in the range of 0.2 to 40 mm, in particular in the range of 1 to 12 mm and particularly preferably in the range of 1 to 6 mm. The features preferably have a size of at least 0.2 mm. The distance of two consecutive features is preferably smaller than an arc length of the sheet-shaped substrate. This ensures that each sheet with overstretched security thread can be safely canceled, as per sheet at least once the elongation can be determined. The distance between two immediately consecutive features can range from 5 to 35 mm. This can e.g. be the case when the sheets are used for banknote production and per sheet in the longitudinal direction of the security thread 5 to 12 notes are to be produced. Since the features are to be contained at least in each banknote, can be selected as the distance of two immediately consecutive features half the banknote height.

When introducing the security thread according to step a) into the substrate, the position of the security thread can oscillate transversely to its longitudinal direction. Of course, this lateral variation of the position of the security thread is taken into account in step d).

A device for producing a sheet-like substrate with a security thread, in particular a banknote paper with a security thread, with a substrate module which introduces a security thread with features spaced apart in the longitudinal direction of the security thread into the substrate such that it is at least partially embedded in the substrate , an image pickup module comprising at least one of Features after embedding the security thread as an image, a control unit which determines the elongation of the embedded security thread in the longitudinal direction on the basis of the image of the at least one feature, and with an invalidation module which deviates the area of the substrate as a function of the elongation determined by the control unit, in which the determined elongation of the security thread exceeds a predetermined maximum elongation provided.

With the device according to the invention can be determined safely and with high accuracy, the elongation of the embedded security thread. This makes it possible to produce a sheet-shaped substrate which contains with highest security no overstretched security thread (the areas with overstretched security thread have been canceled according to the invention).

In the device, the control unit can evaluate the distance between two features in the longitudinal direction for determining the elongation. Furthermore, the control unit may additionally or alternatively evaluate a dimension of the at least one feature (for example, its extension in the longitudinal direction of the security thread and / or transversely thereto) for determining the elongation.

Furthermore, in the device according to the invention, the control unit can perform a pattern comparison between the at least one recorded feature and a stored target image of the feature. This can ensure that even distorted features can be well recognized and evaluated due to the stretching of the security thread.

In the case of the device according to the invention, the control unit can control the embedding of the security thread as a function of the determined elongation via the substrate module in order to prevent exceeding the predetermined maximum elongation of the security thread. This makes it possible to produce the sheet-shaped substrate with the embedded security thread with extremely low rejects.

Furthermore, the device according to the invention can be designed as a papermaking machine (for example as a rotary screen machine) and the substrate module can have a moving screen for producing the substrate, wherein the image recording module is arranged immediately after the screen. Thus, the embedded security thread can still be detected in the moist and not yet dried sheet-shaped substrate, so that the committee can be minimized in the event of overstretching of the security thread.

Alternatively, the image pickup module may be located at the end of the papermaking machine. In particular, the image acquisition module can be arranged after the drying section or immediately before the reeling of the substrate.

The image acquisition module can record the image or the images of the at least one feature in transmitted light or incident light. In particular, the image acquisition module can accommodate several features simultaneously in one shot.

Furthermore, in the device according to the invention, the control unit can control the mechanical tension of the security thread when embedding in the substrate with the substrate module. In particular, the substrate module can have a tension-controlled thread unrolling for this purpose.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations or alone, without departing from the scope of the present invention.

• Fig. 1 eine schematische Darstellung einer Ausführungsform der erfindungsgemäßen Vorrichtung zum Herstellen eines blattförmigen Substrates mit einem Sicherheitsfaden,
• Fig. 2 eine schematische Draufsicht eines Teils eines einzubettenden Sicherheitsfadens,
• Fig. 3 eine schematische Draufsicht eines Abschnitts des blattförmigen Substrates zur Erläuterung der registergenauen Einbringung des Sicherheitsfadens, und
• Fig. 4 eine Draufsicht gemäß Fig. 3 zur Erläuterung einer Alternative der registergenauen Einbringung des Sicherheitsfadens.

The invention will be explained in more detail by way of example with reference to the attached figures, which also disclose features essential to the invention. For better clarity, a scale and proportioned representation is omitted in the figures. Show it:

• Fig. 1 a schematic representation of an embodiment of the inventive apparatus for producing a sheet-shaped substrate with a security thread,
• Fig. 2 a schematic plan view of a part of a security thread to be embedded,
• Fig. 3 a schematic plan view of a portion of the sheet-shaped substrate to explain the register accurate introduction of the security thread, and
• Fig. 4 a plan view according to Fig. 3 to explain an alternative to register accurate introduction of the security thread.

At the schematic in Fig.1 In the embodiment shown, the device according to the invention for producing a substrate with a security thread is designed as a paper-making machine of the round-type and has a sieve tray 4, in which a round screen 5 dips.

Furthermore, the device 1 comprises a take-off screen 6 and a take-off roll 7 for removing the substrate 2 formed on the round screen 5.

The device 1 further comprises a feed module 8 for feeding the security thread 3 to the round screen 5 in order to at least partially embed the security thread 3 in a known manner under tension into the substrate 2, an image acquisition module 9 with a lighting unit 10 and a camera 11, a cancellation module 12 and a control unit 13. The feed module 8 provides a tension-controlled thread unrolling, so that a desired mechanical thread tension (in the longitudinal direction of the security thread 3) can be adjusted during the introduction of the security thread 3.

The device 1 may after the devaluation module 12 still further, known in the art modules such. B. a press section, a dryer section, a reel, etc. For these modules is in Fig.1 representative of a processing module 16 drawn.

During operation of the device 1, sufficient pulp 14 is fed to the screening tray 4, so that upon rotation of the round screen 5 (arrow P1) on the round screen 5, the desired substrate 2 is formed. Further, since the security thread 3 is supplied with the feed module 8 (indicated by the arrow P2), it can be at least partly embedded in the substrate 2 in a known manner (eg as a window thread). Of course, a complete embedding is possible. The operation of the device is controlled or regulated in a known manner. This can be z. B. by the control unit 13 or a control unit, not shown, take place.

The thus formed substrate 2 with the embedded security thread 3 is removed from the round screen 5 with the removal screen 6 and the removal roller 7 (arrow P3) and runs as a substrate web (here still in the aqueous and not yet dried state) through the image acquisition module 9 (by arrow P4 indicated).

The round sieve 5, the sieve tray 4, the feed module 8, the take-off sieve 6 and the take-off roll 7 may together also be referred to as a substrate module.

Features 15, which are arranged periodically in the longitudinal direction of the security thread 3, are recorded as images and supplied to the control unit 13 with the image acquisition module 9.

In Fig. 2 are such features 15 (here as an example of a so-called Cleartextes the number sequence 1234) shown. As can be seen from the illustration, the distance between two adjacent features 15 is thus the period length x1 and the extent of each feature 15 in the longitudinal direction of the security thread 3 is x2 in each case.

The values for x1 and x2 in the unstretched state of the security thread 3 are known. The recordings are preferably carried out in such a way that at least two features 15 are imaged on each recording. On the basis of the images of the features 15 of the embedded security thread 3, the control unit 13 determines the actually existing elongation in the longitudinal direction of the security thread 3 in the embedded state.

Thus, the control unit 13 can determine the value for the distance x1 of two adjacent features 15 of the embedded security thread 3 and with a Compare setpoint. If the determined value for x1 is less than or equal to the target value, for example, the tension of the security thread 3 during feeding can be maintained. If the set point is exceeded, the stretch of the security thread 3 in the embedded state is too great. Therefore, the tension when feeding the security thread 3 is reduced to reduce the elongation of the security thread 3 for the further production of the substrate 2.

Of course, it is also possible to reduce the tension when feeding the security thread 3 when the detected value is close to the target value. These can z. B. one or more areas can be specified. If the determined value for the distance x1 is in one of these ranges, a corresponding reduction of the voltage of the supplied security thread 3 is then effected.

Furthermore, the control unit 13 can actuate the cancellation module 12 if the determined value for the distance x1 is above the desired value, so that the corresponding area of the substrate 2 in which the elongation of the security thread 3 is too large is canceled.

The control unit 13 may additionally or alternatively use the images of the features 15 to evaluate the value for the distance x2. The evaluation is done in a similar way as for the value x1. If a desired value is exceeded, there is an excessive thread stretch, so that on the one hand the tension is reduced when the security thread 3 is fed, and on the other hand the corresponding area of the substrate 2 is invalidated with the cancellation module 12.

The device 1 according to the invention thus has a control circuit which ensures a rapid response to an overstretching of the security thread 3. Furthermore, all areas or bows can be reliably canceled with an overstretched security thread 3 and thus sorted out at the latest during format cutting.

In order to determine the distance x1 and / or x2 from the one or more images of the features 15, z. B. a pattern comparison between a stored pattern (target pattern) of the feature 15 and the recorded feature 15 are performed. With such a pattern comparison, the distance value x1 and / or x2 can be determined quickly with high accuracy. In particular, with the pattern comparison in the recordings, the features can be clearly recognized, even if they are deformed to different degrees due to the existing elongation of the embedded security thread 3.

Of course, the features 15 can not be designed only as clear text. It is also possible that the features 15 contain geometric shapes or are formed as such. So z. B. rectangular marks are used.

As in Fig. 1 is shown schematically, the image pickup module 9 provides transmitted light illumination. This is z. B. with a lighting with wavelengths from the visible wavelength range well possible.

Alternatively, it is of course also possible to provide incident illumination. Furthermore, in addition to or as an alternative to illumination with light from the visible wavelength range, illumination with UV radiation and / or IR radiation are carried out, in particular in an image recording in reflected light.

Since the image pickup module 9 immediately after taking the substrate 2 with the embedded security thread 3 and thus before the dryer section of the papermaking machine 1 performs the image captures, the committee can be quickly recognized and canceled. In addition, a too large thread stretch can be detected and corrected very quickly. As a result, the rejects during substrate production can also be minimized.

Furthermore, in addition to the described evaluation according to the invention, the thread width x3 of the embedded thread 3 can also be determined from the recordings. Thus, another parameter is available, so that the determination of the existing elongation of the security thread 3 in the longitudinal direction can be made even more accurate.

Of course, the image pickup module 9 can still be arranged at other locations of the device 1, which are then further spaced from the take-off roll 7. In all embodiments, the cancellation module 12 is arranged at such a distance from the image acquisition module 9 that a reliable and reliable cancellation can take place upon detection of the overstretching of the security thread 3.

With the device 1 according to the invention a register-accurate insertion of the security thread 3 in the substrate 2 is also possible. Registered thread insertion means that the security thread is limited to the radians of a sheet 17 (FIG. Fig. 3 ) of the sheet-shaped substrate 2 and in addition a feature 15 of each introduced security thread to a Reference mark 19 is placed in the bow 17. In Fig. 3 two security threads 3 are shown, each of which is placed in the sheet 2 with respect to the reference mark 19, which may be a watermark, for example. The areas 18 indicate the banknotes to be produced, all areas 18 forming the so-called benefit area of the sheet 2.

By positioning with respect to the reference mark 19, the features 15 of the security thread 3 can be positioned in the longitudinal direction of the security thread (direction P7) with respect to the useful area. Furthermore, the reference mark 19 is still used for positioning the security threads 3 in the transverse direction (arrow P6).

In Fig. 4 a modification is shown in which the reference mark 19 only serves for positioning the security threads in the transverse direction (arrow P6). For positioning in the longitudinal direction of the security threads 3, a separate reference mark 20, 21 is provided for each security thread 3.

LIST OF REFERENCE NUMBERS

1

contraption

2

substratum

3

security thread

4

Siebtrog

5

Round Screen

6

Abnahmesieb

7

off roll

8th

feeder module

9

Image Capture Module

10

lighting unit

11

camera

12

cancellation module

13

control unit

14

pulp

15

feature

16

processing module

17

bow

18

bill

19-21

reference mark

P1-P7

arrow

x1

period length

x2

Extension of the feature in the longitudinal direction

x3

thread width

Claims (16)

1. A method for manufacturing a sheet-type substrate having a security thread, especially a banknote paper having a security thread, in which

   a) a security thread having features spaced apart from one another in the longitudinal direction of the security thread is inserted into the substrate in such a way that it is at least partially embedded in the substrate,

   b) at least one of the features is displayed as an image after the embedding of the security thread,

   c) the stretch of the embedded security thread in the longitudinal direction is calculated based on the image of the at least one feature, and

   d) the region of the substrate in which the calculated stretch of the security thread exceeds a specified maximum stretch is obliterated depending on the calculated stretch.
2. The method according to claim 1 in which, in step c), the spacing of two features in the longitudinal direction is evaluated to calculate the stretch.
3. The method according to claim 1 or 2 in which, in step c), a dimension of the at least one feature is evaluated to calculate the stretch.
4. The method according to one of the above claims in which, in step c), a pattern matching is carried out between the at least one recorded feature and a stored target image of the feature.
5. The method according to one of the above claims in which step a) of the embedding of the security thread is controlled depending on the stretch calculated in step c) to prevent an exceedance of the specified maximum stretch of the security thread.
6. The method according to one of the above claims in which the substrate having the embedded security thread is manufactured in a paper manufacturing machine having a moving mold, step b) being carried out immediately after the substrate is removed from the mold, or in which the substrate having the embedded security thread is manufactured in a paper manufacturing machine having a moving mold, step b) being carried out at the end of the paper manufacturing machine.
7. The method according to one of the above claims in which, in step b), the recording is produced in transmitted light, or in which, in step b), the recording is carried out in reflected light.
8. The method according to one of the above claims in which, in step d), the mechanical tension of the security thread is controlled upon embedding in step a).
9. The method according to one of the above claims in which the features are gaps, especially in the form of a number, letter and/or character string, in an opaque coating.
10. A device for manufacturing a sheet-type substrate (2) having a security thread (3), especially a banknote paper having a security thread, having
    a substrate module (4, 5, 6, 7, 8) that inserts into the substrate (2), in such a way that it is at least partially embedded in the substrate (2), a security thread (3) having features (15) spaced apart from one another in the longitudinal direction of the security thread (3),
    an image recording module (9) that displays at least one of the features (15) as an image after the embedding of the security thread (3),
    a control unit (13) that calculates the stretch of the embedded security thread (3) in the longitudinal direction based on the image of the at least one feature (15), and
    having an obliteration module (12) that, depending on the stretch calculated by the control unit (13), obliterates the region of the substrate (2) in which the calculated stretch of the security thread (3) exceeds a specified maximum stretch.
11. The device according to claim 10 in which the control unit (13) evaluates the spacing (x1) of two features (15) in the longitudinal direction to calculate the stretch.
12. The device according to claim 10 or 11 in which the control unit (13) evaluates a dimension (x2) of the at least one feature (15) to calculate the stretch.
13. The device according to one of claims 10 to 12 in which the control unit (13) carries out a pattern matching between the at least one recorded feature (15) and a stored target image of the feature.
14. The device according to one of claims 10 to 13 in which the control unit (13) controls, depending on the calculated stretch, via the substrate module (4 - 8), the embedding of the security thread (3) to prevent an exceedance of the specified maximum stretch of the security thread (3).
15. The device according to one of claims 10 to 14 in which the device is developed as a paper manufacturing machine and the substrate module (4 - 8) exhibits a moving mold (5) for manufacturing the substrate (2), the image recording module (9) being arranged immediately after the mold (5), or in which the device is developed as a paper manufacturing machine and the substrate module (4 - 8) exhibits a moving mold (5) for manufacturing the substrate (2), the image recording module (9) being arranged at the end of the paper manufacturing machine.
16. The device according to one of claims 10 to 15 in which the control unit (13) controls the mechanical tension of the security thread (3) upon embedding in the substrate (2).

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