EP2943340B1 - Method for producing a continuous paper web - Google Patents

Description

The invention relates to a method for producing an endless paper web provided with at least one film.

In the production of continuous paper webs for security and value documents, which are provided with films or film elements such as security threads, security strips or label-like film elements or patches, the registered application of the films is often based on the sensory scanning of a printed mark applied to the paper web. However, register-accurate application of the film can be affected by soiling or other marks on the paper web.

document WO 03/054297 A2 describes a security paper for the production of security documents, such as banknotes, ID cards or the like, having at least one through-opening, wherein the opening is produced during papermaking and has no sharp boundary edge in the edge region.

Based on this, the present invention seeks to provide a manufacturing method of the type mentioned, in which the registered application of the film can be performed with higher accuracy.

This object is achieved by the method having the features of independent claim 1. Further developments of the invention are the subject of the dependent claims.

Summary of the invention

1. 1. (First aspect of the invention) Method for producing an endless paper web for the production of security and value documents, with the method steps:
   1. a) producing an endless paper web on a rotary screening machine, wherein the paper web is subdivided into a plurality of equal, transversely to the endless longitudinal direction extending paper sheets, and providing at least one paper sheet per screen circumference of the round screen with at least one watermark for the control of further processing steps, wherein between the positions of the watermark marks of the paper sheets have certain positional deviations;
   2. b) detecting the positions of two or more watermark marks on the endless paper web;
   3. c) determining marker positions with smaller position deviations than the position deviations of the detected watermark marks;
   4. d) generating colored identification marks at the designated mark positions of the paper web;
   5. e) detecting the positions of the generated identification marks;
   6. f) providing the paper web having at least one through opening in each of the paper sheets using the detected positions of the generated indicia marks, the through apertures each having exactly one straight edge perpendicular to the longitudinal direction of the continuous paper web (ie, perpendicular to the web direction of the paper web);
   7. g) detecting the positions of the straight edges contained in the generated through holes; and
   8. h) providing the paper web with at least one film with security features to be applied to the paper web on each of the paper sheets using the detected positions of the straight edges contained in the generated through openings.
2. 2. (Preferred Embodiment) Method according to paragraph 1, wherein the identification marks are generated in step d) with a non-contact method.
3. 3. (Preferred embodiment) The method according to paragraph 2, wherein the identification marks are generated in step d) in the inkjet method. Furthermore, it is preferred that an ink flight time compensation is performed.
4. 4. (Preferred embodiment) The method according to paragraph 2, wherein the identification marks are generated in step d) by laser marking, preferably in step a) laser-sensitive feature substances are introduced into the paper or laser-sensitive feature substances are applied to the paper web after paper production.
5. 5. (Preferred embodiment) Method according to paragraph 4, wherein in step d) by laser marking at the same time on the front and back of the paper web identification marks are generated.
6. 6. (Preferred embodiment) Method according to paragraph 1, wherein the identification marks are produced in step d) with a printing process, in particular in rotary flexographic printing, rotary offset printing or rotary screen printing.
7. 7. (Preferred embodiment) Method according to at least one of paragraphs 1 to 6, wherein in step d) dark, in particular black identification marks are produced.
8. 8. (Preferred embodiment) The method according to any one of paragraphs 1 to 7, wherein the method is carried out by means of a device with
   • a transport device for transporting the endless paper web;
   • a first detecting means for detecting the positions of two or more watermark marks on the endless paper web;
   • a first evaluation device for determining the brand positions with lower position deviations;
   • a marking device for generating the colored identification marks at the determined mark positions of the paper web;
   • second detection means for detecting the positions of generated flags;
   • means for producing the through openings in the paper web using the detected positions of the generated identification marks, the through openings each having exactly one straight edge arranged perpendicular to the longitudinal direction of the endless paper web;
   • third detecting means for detecting the positions of the straight edges contained in the generated through holes; and
   • a device for applying the film with security features to be applied to the paper web to the paper web using the detected positions of the straight edges contained in the generated through openings.
9. 9. (Preferred Embodiment) The method of paragraph 8, wherein the third detecting means for detecting the positions of the straight edges contained in the generated through-holes comprises a contrast sensor or a transilluminating sensor.
10. 10. (Preferred Embodiment) Method according to paragraph 8 or 9, wherein the labeling means comprises an inkjet printer or a laser writer.

Detailed description of the invention

According to the invention, it is sufficient to provide a paper sheet per screen circumference of the round screen of the paper machine with a watermark. However, it is of course possible to provide several or even all the paper sheets with watermark marks per screen circumference.

The identification marks can be generated in step d) by a touching method. In an advantageous variant of the invention, however, the identification marks are generated in step d) with a non-contact method. In particular, it has proven useful to apply the identification marks in step d) in the inkjet process, wherein due to the finite time of flight of the ink droplets from the print head to the paper web advantageously an ink flight time compensation is performed.

A particular advantage of inkjet-applied markers is that there is no need to extract smoke or chips as would be necessary with a laser-cut mark. In addition, inkjet printers are very compact devices that can be easily integrated into existing equipment. Generally one can Colored identification mark, unlike when using a hole as a tax stamp, after the cross cutting does not hinder the stacking of the individual sheets of paper or lead to a snagging of the holes.

In a further advantageous non-contact method, the identification marks are generated in step d) by laser marking. For this purpose, in a preferred embodiment of the invention, laser-sensitive feature substances can already be introduced into the paper in step a). Alternatively or additionally, laser-sensitive feature substances can also be applied to the paper web after papermaking. Suitable laser-sensitive feature substances are a multiplicity of substances known per se to the person skilled in the art, such as TiO ₂ , soot particles or infrared absorbers. By laser application, the laser-sensitive feature substances are locally modified, for example dyed and preferably blackened, and thereby form a machine-detectable identification mark.

In a preferred embodiment, identification marks are simultaneously generated on the front and back of the paper web in step d) by laser marking.

In another, likewise advantageous variant of the invention, the identification marks are produced in step d) using any printing method, in particular in rotary flexographic printing, rotary offset printing, rotary screen printing or gravure printing.

In all variants, dark or even black identification marks are advantageously generated in step d), which can be recognized particularly easily and reliably by sensors. The colored identification marks can also be produced with dyes that are not visible in the visible spectral range or only after excitation, such as IR or UV dyes or luminescent dyes.

In step e), the positions of the generated identification marks are detected, and in the subsequent step f), at least one through opening is produced in each of the paper sheets using the detected positions of the identification marks, the through openings each being exactly one perpendicular to the longitudinal direction of the endless paper web straight edge (hereinafter also referred to as "window sill").

The through hole created in the paper web will also be referred to as "window" hereinafter.

In step g), the positions of the straight edges contained in the generated through-holes are detected, and in the subsequent step h), the paper web is provided with at least one sheet (or sheet member) with security features to be applied to the paper web at each of the paper sheets using the detected positions of the straight edges contained in the generated through openings. The film may in particular be a security thread, a security strip or a label-like film element or patch. The film can in particular be applied to the paper web so that it closes the through opening on one side.

• aus den erfassten Positionen der geraden Kanten die aktuelle Länge eines Papierbogens bestimmt wird und
• eine Folie mit auf die Papierbahn aufzubringenden Sicherheitsmerkmalen entsprechend der aktuellen Bogenlänge gedehnt und auf die Papierbahn aufgebracht wird.

According to a preferred embodiment variant, a so-called insertion area, in which a scanning sensor is active, is located above the straight edge to be sensed in the direction of travel of the paper sheet. The scanning sensor detects the straight edge and gives feedback to the register control for register accurate application of the film. The register-accurate application of the film can be done in particular by the fact that

• from the detected positions of the straight edges, the actual length of a paper sheet is determined and
• a film is stretched with applied to the paper web security features according to the current sheet length and applied to the paper web.

As a scanning sensor, in particular a contrast sensor or transmitted light sensor can be provided. By means of the above-described fading technique, which provides a scanning sensor which is active within a certain fade-in area (hereinafter also referred to as "reading window"), unwanted interfering pulses can be prevented.

The through openings can be produced, for example, by a (in particular rotary) punch or by a laser cutter. This creates sharp edges that can provide a more accurate signal to drive additional processing than printed marks.

It is particularly preferred that the straight edge contained in the through opening and arranged perpendicularly to the longitudinal direction of the endless paper web is delimited by two edges that are perpendicular to the straight edge. The two edges adjoining the straight edge at right angles are therefore arranged parallel to the longitudinal direction of the endless paper web. Thus, the through hole may, in particular, have the shape of a shield with a semicircular rounded tip resembling a "U" (the window is similar in this case the so-called Spanish, Portuguese or Flemish shield). Of course, the tip does not necessarily have to be rounded in a semicircle, that is to say the through opening may also have approximately the shape of a triangle (the window in this case resembles the so-called old French shield, see Fig. 2 ).

• einer Transporteinrichtung zum Transport der endlosen Papierbahn;
• einer ersten Erfassungseinrichtung zum Erfassen der Positionen von zwei oder mehr Wasserzeichenmarken auf der endlosen Papierbahn;
• einer ersten Auswerteeinrichtung zum Bestimmen der Markenpositionen mit geringeren Positionsabweichungen;
• einer Kennzeichnungseinrichtung zum Erzeugen der farbigen Kennzeichnungsmarken an den bestimmten Markenpositionen der Papierbahn;
• einer zweiten Erfassungseinrichtung zum Erfassen der Positionen von erzeugten Kennzeichnungsmarken;
• einer Einrichtung zum Erzeugen der durchgehenden Öffnungen in der Papierbahn unter Verwendung der erfassten Positionen der erzeugten Kennzeichnungsmarken, wobei die durchgehenden Öffnungen jeweils genau eine, senkrecht zur Längsrichtung der endlosen Papierbahn angeordnete gerade Kante aufweisen;
• einer dritten Erfassungseinrichtung zum Erfassen der Positionen der in den erzeugten durchgehenden Öffnungen enthaltenen geraden Kanten; und
• einer Einrichtung zum Aufbringen der Folie mit auf die Papierbahn aufzubringenden Sicherheitsmerkmalen auf die Papierbahn unter Verwendung der erfassten Positionen der in den erzeugten durchgehenden Öffnungen enthaltenen geraden Kanten.

The invention also relates to a device for carrying out the method described, with

• a transport device for transporting the endless paper web;
• a first detecting means for detecting the positions of two or more watermark marks on the endless paper web;
• a first evaluation device for determining the brand positions with lower position deviations;
• a marking device for generating the colored identification marks at the determined mark positions of the paper web;
• second detection means for detecting the positions of generated flags;
• means for producing the through openings in the paper web using the detected positions of the generated identification marks, the through openings each having exactly one straight edge arranged perpendicular to the longitudinal direction of the endless paper web;
• third detecting means for detecting the positions of the straight edges contained in the generated through holes; and
• a device for applying the film with applied to the paper web security features on the paper web below Use of the detected positions of the straight edges contained in the generated through holes.

The marking device preferably comprises an inkjet printer or a laser writer. The laser source is advantageously an infrared laser in the wavelength range from 0.8 μm to 3 μm, in particular a Nd: YAG laser or a Nd: YVO ₄ laser, or else a CO ₂ laser with a wavelength of 10.6 μm for use.

Furthermore, the principles described can also be used advantageously in the production of pure polymer banknotes since, although there are no watermark marks, the problem of the different influence of a deviating arc length on methods with rigid or flexible tools also exists.

Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation true to scale and proportion has been dispensed with in order to increase the clarity. The various embodiments are not limited to use in the specific form described, but can also be combined with each other.

Fig. 1

eine endlose Papierbahn, die in eine Mehrzahl gleicher, sich quer zu der endlosen Längsrichtung erstreckende Papierbögen unterteilt ist,

Fig. 2

einen einzelnen Papierbogen der Papierbahn der Fig. 1, wobei der Bogen mit durchgehenden Öffnungen versehen ist, die jeweils genau eine senkrecht zur Bahnlaufrichtung der Papierbahn angeordnete gerade Kante aufweisen; und

Fig. 3

einen Einzelnutzen eines Papierbogens, der mit einer durchgehenden Öffnung versehen ist.

Show it:

Fig. 1

an endless paper web which is subdivided into a plurality of equal paper sheets extending transversely to the endless longitudinal direction,

Fig. 2

a single sheet of paper the paper web Fig. 1 wherein the sheet is provided with through openings, each having exactly one perpendicular to the web running direction of the paper web arranged straight edge; and

Fig. 3

a single benefit of a paper sheet, which is provided with a through opening.

The invention will now be explained using the example of an endless paper web for the production of banknotes. FIG. 1 shows for this purpose an endless paper web 10 which is subdivided into a plurality of identical paper sheets 12 _n-1, 12 _n , 12 _{n + 1} extending transversely to the endless longitudinal direction 18. The boundary lines 14 of the individual paper sheets 12 are imaginary lines that are in Fig. 1 are shown for illustration, but are not present on the paper web as visible marking lines.

In the production of the paper web 10 at least one watermark 20 was introduced in each sheet of paper 12 for the control of further processing steps. The introduction of such watermark marks 20 is very easy and inexpensive possible in papermaking. However, due to the production of the watermark marks 20, they have a relatively large positional tolerance, so that there are certain positional deviations between the positions of the watermark marks 20 of the same paper sheets 12.

By way of illustration, in Fig. 1 the watermark marks 20 with their distance x _k from the boundary line 14 of the associated paper sheet 12 _k for k = n, n + 1 shown schematically. The mentioned position tolerance the watermark marks 20 then means that the distance values x _n-1, x _n, x _{n + 1,} etc. have a relatively large variation.

In order to improve the accuracy of subsequent application steps against the use of the watermark marks 20 as control marks, the positions of two or more watermark marks 20 on the endless paper web 10 are detected and mark positions are calculated which have lower position deviations than the watermark marks 20.

sind dann Markenpositionen y_n mit geringeren Positionsabweichungen als den Positionsabweichungen der Wasserzeichenmarken 20 gegeben, da sich deren zufällige Positionsschwankungen bei der Berechnung herausmitteln.Such a determination of brand positions with smaller position deviations can be done, for example, by averaging the detected positions. Since banknote paper is usually made in a rotary screen technique, the position of a watermark 20 is repeated approximately with each screen circumference. Therefore, it is advantageous to averaged over a multiple of watermark marks 20 per screen circumference to determine more accurate label positions. In the embodiment, about m watermark marks 20 come on a Siebumfang and it is averaged over three Siebumfänge. For the averaging, a shift register is advantageously used, in which the position of a newly detected watermark mark x _n replaces the oldest detected position x _n-3m . By $${\mathrm{y}}_{\mathrm{n}}={\displaystyle \underset{i=0}{\overset{3m-1}{\Sigma }}\frac{{\mathrm{x}}_{\mathrm{n}-\mathrm{i}}}{3\mathrm{m}}}$$

are then given brand positions y _n with position deviations less than the position deviations of the watermark marks 20, since their random position fluctuations in the calculation out.

At the brand positions y _n calculated in this way, colored identification marks 22, which are used as control marks for the further application steps and which improve the positional accuracy of the subsequent application steps due to their smaller position deviations, are now produced with a non-contact method.

For the production of such colored identification marks 22, the inkjet method has proven particularly useful. An applied by inkjet printer, usually black marking mark 22 can be easily detected by a machine by machine. In addition, inkjet printers have a very compact design and can therefore be easily integrated into existing systems. When applying the identification marks 22 by inkjet method, no extraction of smoke or accumulated snippets is required. In addition, unlike a through opening after cross-cutting, an applied colored marker may not interfere with the stacking of the paper sheets 12 or cause the through holes to get caught.

Since the print head of an inkjet printer has a certain distance from the paper web 10, due to the rapid movement of the paper web 10, the time of flight of the ink droplets is taken into account as a function of the web speed during printing.

In another embodiment of the invention, the colored identification marks 22 are formed by a laser mark. For this purpose, for example, laser-sensitive feature substances can already be introduced into the paper during papermaking, or laser-sensitive feature substances can be applied to the paper web after papermaking. As laser-sensitive feature substances are, for example, TiO ₂ , Soot particles or infrared absorber into consideration. As a result of the laser application, the laser-sensitive feature substances are locally modified, for example colored or blackened.

A particular advantage of this variant of the invention is that the laser radiation can reach through the paper web, so that identification marks can be generated simultaneously on the front and back of the paper web in one operation. The identification marks on the front and back are perfectly matched to each other and allow a highly accurate alignment of subsequent processing steps on both the marks on the front and on the marks on the back.

In addition to the non-contact methods for applying the identification marks 22, other printing methods, such as rotary flexographic printing, rotary offset printing or rotary screen printing, can also be considered.

In an advantageous variant of the invention, the printing of the identification marks 22 takes place in one operation with the imprinting of a printing feature. In this case, the tags 22 may be integrated into the print tool so that they are perfectly matched to the print image of the print feature. For example, an identification mark can be integrated in the rotary screen in the printing screen. The subsequent applications controlled on the identification mark generated during the printing step then have a very good registration with the print images of the printing step.

In general, in subsequent applications, the positions of the generated identification marks 22 are advantageously detected and the paper web 10 is provided with at least one through opening using the detected positions of the tags in each of the paper sheets. This can be accomplished by means of a rigid tool, such as a rotary punch, or by means of a flexible tool, such as a laser cutting machine.

FIG. 2 shows a single sheet of paper 12 of the paper web 10 with watermark 20 and identification mark 22. Each sheet of paper 12 carries a plurality of individual benefits 16, which correspond to the later cut banknotes in the embodiment. The nominal length of a single sheet of paper 12 is denoted by Ls.

The individual benefits 16 are provided after papermaking in the further processing of the paper web 10 in two separate application steps with two security features, which are aligned in the target image and complement each other to form an overall feature 34.

The first security feature is a continuous opening 30 produced by means of laser radiation or punching, which is formed in the paper sheet 12. The opening 30 has exactly one perpendicular to the web running direction 18 of the endless paper web arranged straight edge.

The second security feature is a security feature applied with a rigid tool, in the exemplary embodiment a film feature present on an endless film strip 32, which is applied to the paper sheet 12 together with the film strip 32. Assign the film features and through holes 30 their in Fig. 2 shown target positions, they complement each other without offset to the overall feature 34.

In the exemplary embodiment, for the application of the film features, the positions of the straight edges contained in the continuous openings 30 are detected and the current length of a paper sheet 12 is calculated from the detected positions of the straight edges. Then, a film strip 32 is stretched with the applied to the paper web 10 film features according to the current sheet length and applied to the paper web 10.

The step of detecting the positions of the straight edges contained in the through holes 30 will be described with reference to FIGS Fig. 3 explained in more detail.

Fig. 3 shows a single piece 16 of a paper sheet, which is provided with a through hole 30. The opening 30 contains exactly one perpendicular to the web running direction 18 of the endless paper web arranged straight edge 50, which is scanned by a contrast sensor or transmitted light sensor. The reference number 60 designates the overlay area in which the scanning sensor (for example a contrast sensor or transmitted-light sensor) is active. The scanning sensor detects the straight edge 50 and provides feedback to the register control for registration of the film. The register-accurate application of the film can in particular be effected by determining the actual length of a paper sheet from the detected positions of the straight edges 50 and stretching a film 32 with security features to be applied to the paper web according to the current sheet length and applying it to the paper web.

Claims (10)

1. A method for manufacturing an endless paper web (10) for manufacturing security documents and value documents, having the method steps of:

   a) producing an endless paper web (10) on a cylindrical screen machine, wherein the paper web (10) is subdivided into a plurality of equal paper sheets (12) extending transversally to the endless longitudinal direction (18), and equipping at least one paper sheet (12) per screen circumference of the cylindrical screen with at least one watermark marker (20) for controlling further processing steps, wherein there exist certain position variances between the positions of the watermark markers (20) of the paper sheets (12),

   b) capturing the positions of two or more watermark markers (20) on the endless paper web (10),

   c) determining of marker positions having smaller position variances than the position variances of the captured watermark markers (20),

   d) producing colored identification markers (22) in the determined marker positions of the paper web (10),

   e) capturing the positions of the produced identification markers (22),

   f) equipping the paper web (10) with at least one through opening (30) in each of the paper sheets (12), making use of the captured positions of the produced identification markers (22), wherein the through openings (30) have respectively exactly one straight edge (50) arranged perpendicularly to the longitudinal direction of the endless paper web (10),

   g) capturing the positions of the straight edges (50) contained in the produced through openings (30), and

   h) equipping the paper web (10) on each of the paper sheets (12) with at least one foil (32) having security features to be applied to the paper web (10), making use of the captured positions of the straight edges (50) contained in the produced through openings (30).
2. The method according to claim 1, characterized in that in step d) the identification markers (22) are produced with a contactless method.
3. The method according to claim 2, characterized in that in step d) the identification markers (22) are produced in the inkjet method, preferably that an ink flight-time compensation is performed therein.
4. The method according to claim 2, characterized in that in step d) the identification markers (22) are produced by laser marking, wherein preferably in step a) laser-sensitive feature substances are incorporated in the paper or laser-sensitive feature substances are applied to the paper web (10) after the paper manufacture.
5. The method according to claim 4, characterized in that in step d) identification markers (22) are produced by laser marking simultaneously on the front side and back side of the paper web.
6. The method according to claim 1, characterized in that in step d) the identification markers (22) are produced with a printing method, in particular rotary flexographic printing, rotary offset printing or rotary screen printing.
7. The method according to at least one of claims 1 to 6, characterized in that in step d) dark, in particular black, identification markers (22) are produced.
8. The method according to any one of claims 1 to 7, wherein the method is performed by means of an apparatus having

   - a transport device for transporting the endless paper web (10),

   - a first capturing device for capturing the positions of two or more watermark markers (20) on the endless paper web (10),

   - a first evaluation device for determining the marker positions having smaller position variances;

   - a marking device for producing the colored identification markers (22) in the determined marker positions of the paper web (10),

   - a second capturing device for capturing the positions of produced identification markers (22),

   - a device for producing the through openings (30) in the paper web (10), making use of the captured positions of the produced identification markers (22), wherein the through openings (30) have respectively exactly one straight edge (50) arranged perpendicularly to the longitudinal direction of the endless paper web (10),

   - a third capturing device for capturing the positions of the straight edges (50) contained in the produced through openings (30),

   - a device for applying to the paper web (10) the foil (32) having security features to be applied to the paper web (10), making use of the captured positions of the straight edges (50) contained in the produced through openings (30).
9. The method according to claim 8, characterized in that the third capturing device for capturing the positions of the straight edges (50) contained in the produced through openings (30) comprises a contrast sensor or a transmitted light sensor.
10. The method according to claim 8 or 9, characterized in that the marking device comprises an inkjet printer or a laser writer.

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