ES2665760T3 - Procedure to make an endless paper band - Google Patents

Abstract

Procedure for manufacturing an endless paper band (10) for the manufacture of security documents and valuable documents with the procedure steps: a) manufacturing an endless paper band (10) in a cylindrical mesh machine, being divided the paper strip (10) on a plurality of equal sheets of paper (12) extending transversely to the endless longitudinal direction (18), and providing at least one sheet of paper (12) for each perimeter of the cylindrical mesh of at least one watermark (20) to control the following processing steps, there being between the positions of the watermarks (20) of the paper sheets (12) certain position deviations, b) detecting the positions of two or more watermarks (20) on the endless paper web (10), c) determining marking positions with smaller position deviations than the position deviations of the watermarks (20) detected, d) create color identification marks (22) at the determined marking positions of the paper strip (10), e) detecting the positions of the identification marks (22) created, f) providing the paper strip (10) with at least one through opening (30) on each of the sheets of paper (12) using the detected positions of the identification marks (22) created, such that each of the through openings (30) has exactly a straight edge (50) arranged in the direction perpendicular to the longitudinal direction of the endless paper band (10), g) detect the positions of the straight edges (50) contained in the through openings (30) created, and h) provide the paper band (10) with at least one sheet (32) with safety features to be applied on the paper web (10) on each of the paper sheets (12) using the detected positions of the straight edges (50) contained in the through openings (30 ) created.

Description

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DESCRIPTION

Procedure to make an endless paper band

The invention relates to a process for manufacturing an endless paper web provided with at least one sheet.

In the manufacture of endless paper strips for security documents and valuable documents provided with sheets or foil elements, such as security threads, security strips or foil elements or label patches, the application to registers to the sheets It takes place frequently based on the sensor scanning of a print mark applied on the paper web. However, the application to registers to the sheet with accuracy can be affected by fouling or other marks on the paper web.

WO 03/054297 A2 describes a security paper for the manufacture of security documents, such as banknotes, identity cards or the like, with at least one through opening, such that the opening was created during papermaking and it does not present any live limiting edge in the edge zone.

Based on this basis, the object of the invention is to indicate a manufacturing process of the type mentioned at the beginning, in which the application can be made to registers of the sheet with greater precision.

This objective is achieved by the method with the features of the independent claim 1. Additional embodiments of the invention are the subject of the dependent claims.

Summary of the Invention

1. (First aspect of the invention) Procedure for manufacturing an endless paper web for the manufacture of security documents and valuable documents with the procedural steps:

a) Manufacture an endless paper band in a cylindrical mesh machine, the paper band being divided into a plurality of equal sheets of paper that extend transversely to the endless longitudinal direction, and provide at least one sheet of paper for each perimeter of the cylindrical mesh of at least one watermark to control the following processing steps, certain position deviations exist between the watermark positions of the paper sheets;

b) detect the positions of two or more watermarks on the endless paper web;

c) determine brand positions with smaller position deviations than the position deviations of the detected watermarks;

d) create color identification marks at certain mark positions of the paper band;

e) detect the positions of the identification marks created;

f) provide the paper strip with at least one through opening in each of the sheets of paper using the detected positions of the identification marks created, such that each of the through openings has exactly a straight edge arranged perpendicularly to the longitudinal direction of the endless paper web (i.e. perpendicular to the direction of advance of the paper web).

g) detect the positions of the straight edges contained in the created through openings; Y

h) provide the paper strip with at least one sheet with safety features to be applied to the paper strip in each of the sheets of paper using the detected positions of the straight edges contained in the created through openings.

2. (Preferred embodiment) Procedure, according to paragraph 1, in which the identification marks of step d) are created with a contactless procedure.

3. (Preferred embodiment) Procedure, according to paragraph 2, in which the identification marks of step d) are created in an inkjet procedure. In addition, in this case it is preferred to make a flight time offset of the ink.

4. (Preferred embodiment) Procedure, according to paragraph 2, in which the identification marks of step d) are created by laser marking, such that, preferably in step a), laser-sensitive characteristic substances are incorporated into the paper or, after papermaking, laser sensitive substances are applied to the paper web.

5. (Preferred embodiment) Procedure, according to paragraph 4, in which, by laser marking in step d), identification marks are simultaneously created on the front side and the back side of the paper web.

6. (Preferred embodiment) Procedure, according to paragraph 1, in which the identification marks of step d) are created with a printing procedure, in particular, rotary flexo printing, rotary offset printing or rotary screen printing.

7. (Preferred embodiment) Procedure, according to at least one of paragraphs 1 to 6, such that in step d) they are created

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dark identification marks, in particular black.

8. (Preferred embodiment) Procedure, according to any of paragraphs 1 to 7, such that the procedure is performed by a device with

- a conveyor device for transporting the endless paper web;

- a first detection device to detect the positions of two or more watermarks on the endless paper web;

- a first evaluation device to determine the positions of the marks with lower position deviations;

- a marking device for creating the color identification marks at the determined marking positions of the paper web;

- a second detection device to detect the positions of the identification marks created;

- a device for creating the through openings in the paper web using the detected positions of the created identification marks, such that each of the through openings has exactly a straight edge arranged perpendicular to the longitudinal direction of the paper web endless;

- a third detection device for detecting the positions of the straight edges contained in the created through openings; Y

- a device for applying the sheet on the paper web with the safety features to be applied thereon, using the detected positions of the straight edges contained in the created through openings.

9. (Preferred embodiment) A method, according to paragraph 8, in which the third detection device for detecting the positions of the straight edges contained in the created through openings comprises a contrast sensor or a transparency sensor.

10. (Preferred embodiment) A method, according to any of paragraphs 8 or 9, wherein the marking device comprises an inkjet printer or a laser engraver.

Detailed description of the invention

According to the invention, it is sufficient to provide a sheet of paper with a watermark for each perimeter of the cylindrical mesh of the paper machine. However, of course it is also possible to provide several or even all sheets of paper for each perimeter of watermark mesh.

Identification marks can be created in step d) with a contact procedure. However, in a preferred variant of the invention, the identification marks of step d) are created with a contactless process. In particular, the application of the identification marks in step d) has been proven effective with an inkjet process, advantageously performing a time-of-flight compensation of the ink due to the limited flight time of the drops of ink from the print head to the paper band.

A special advantage of the identification marks applied by inkjet process is that no aspiration is required for smoke or generated fragments, as would be necessary in the case of a laser cut mark. In addition, inkjet printers are very compact equipment that can be easily integrated into existing installations. In general, unlike the use of a hole as a control mark, a color identification mark cannot impede the stacking of the individual sheets of paper nor cause a hole engagement after cross-cutting.

In the case of another advantageous non-contact procedure, the identification marks are created in step d) by laser marking. To this end, in a preferred embodiment of the invention, in step a), laser sensitive characteristic substances are already incorporated into the paper. Alternatively or additionally, also after papermaking it is possible to apply characteristic substances sensitive to the laser on the paper web. As characteristic substances sensitive to the laser, several substances known to the expert are considered, for example, TiO2, soot particles or infrared absorbers. By laser application, for example, they color and preferably blacken the characteristic substances sensitive to the laser, forming an identification mark that can be detected mechanically.

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

In the case of another variant of the invention, also advantageous, the identification marks of step d) are created with any printing method, in particular, by rotary flexo printing, rotary offset printing, rotary screen printing or printing in gravure.

In all variants, in step d) dark or even black identification marks are advantageously created, which can be recognized by sensors in a particularly simple and safe way. Color identification marks can also be created with inks that are not visible in the visible spectral range or are not visible until excited, such as IR or UV inks or luminescent inks.

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In step e) the positions of the created identification marks are detected and in the subsequent step f) at least one through opening is created in each sheet of paper using the detected positions of the identification marks, such that each of the through openings have exactly a straight edge arranged perpendicular to the longitudinal direction of the endless paper web (which is also referred to below as the "window ledge").

The through opening created in the paper web is also referred to below as "window."

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

According to a preferred variant of the invention, above the straight edge to be detected by sensor, in the direction of advance of the paper sheet, there is a so-called viewing area, in which a scanning sensor is active. The scanning sensor detects the straight edge and responds to the registration control for the application of the sheet with registration accuracy. The application of the sheet with registration accuracy can be carried out, in particular,

- determining, from the detected positions of the straight edges, the current length of a sheet of paper and

- extending a sheet with the safety features to be applied on the paper web based on the current length of the paper and applied on the paper web.

As a scanning sensor, in particular, a contrast sensor or a transparency sensor can be provided. By means of the visualization technique described above, which provides for an active scanning sensor within a given viewing area (also referred to below as the "reading window"), undesired interference pulses can be avoided.

Through openings can be created, for example, by a punch (especially rotary) or by a laser cutter. This creates live edges that can provide a more accurate signal than the printed marks for the control of the next processing steps.

It is especially preferred that the straight edge contained in the through opening, arranged perpendicular to the longitudinal direction of the endless paper web, is limited by two edges that limit at right angles to the straight edge. That is, the edges that limit with the straight edge are arranged parallel to the longitudinal direction of the endless paper web. Therefore, the through opening can, in particular, have the shape of a shield or a coat of arms with a rounded tip in a semicircular shape, similar to a "U" (in this case the window resembles the so-called Spanish shield , Portuguese or Flemish). Naturally, the tip does not necessarily have to be rounded in a semicircular shape, that is, the through opening can also have approximately the shape of a triangle (in this case the window resembles the so-called old French shield, see figure 2).

The invention also relates to a device for performing the procedure described with

- a conveyor device for transporting the endless paper web;

- a first detection device to detect the positions of two or more watermarks on the endless paper web;

- a first evaluation device to determine the positions of the marks with lower position deviations;

- a marking device for creating the color identification marks at the determined marking positions of the paper web;

- a second detection device to detect the positions of identification marks created;

- a device for creating the through openings in the paper web using the detected positions of the created identification marks, such that each of the through openings has exactly a straight edge arranged perpendicular to the longitudinal direction of the paper web endless;

- a third detection device for detecting the positions of the straight edges contained in the created through openings; Y

- a device for applying the sheet on the paper web with the safety features to be applied thereon, using the detected positions of the straight edges contained in the created through openings.

Preferably, the marking device comprises an inkjet printer or a laser engraver. As the laser source, an infrared laser in the wavelength range of 0.8 pm to 3 pm is advantageously used, in particular, an Nd: YAG laser or an Nd: YVO4 laser, or also a CO2 laser with a length 10.6 pm wave

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The principles described can also be used advantageously in the manufacture of pure polymer banknotes, since, although in that case no watermarks are available, however, there is also the problem of the different influence of a sheet length different about procedures with rigid or flexible tools.

Other embodiments, as well as advantages of the invention, are explained below based on the figures, in whose representation a reproduction with proportions and real scales has been dispensed with to increase clarity. The different embodiments are not limited to use in the manner described in particular, but can also be combined with each other.

They show:

Figure 1, an endless paper web that is divided into multiple sheets of paper that extend perpendicularly to the endless longitudinal direction,

Figure 2, an individual paper sheet of the paper band of Figure 1, the sheet being provided with through openings each having exactly a straight edge arranged perpendicular to the direction of advance of the paper web ; Y

Figure 3, an individual copy of a sheet of paper that is provided with a through opening.

The invention is now explained based on the example of an endless paper band for the manufacture of bills. In this sense, Figure 1 shows an endless paper band -10- that is divided into multiple sheets of paper -12n-1-, -12n-, -12n + 1- same that extend perpendicular to the direction Longitudinal endless -18-. The delimitation lines -14- of the individual sheets of paper -12- are imaginary lines, which in Figure 1 are represented for clarity but, nevertheless, are not present as visible marking lines on the paper web.

In the manufacture of the paper web -10- at least one watermark -20- was incorporated in each paper sheet -12- for the control of the following processing steps. The incorporation of these watermarks -20- can be carried out very easily and economically during papermaking. However, the watermarks -20- have a relatively large position tolerance conditioned by the manufacturing, so that between the positions of the watermarks -20- of the same sheets of paper -12- there are certain position deviations .

For clarity, in figure 1 the watermarks -20- have been schematically drawn with their distance -xk- to the delimitation line -14- of the corresponding sheet of paper -12k- for k = n, n + 1 . The mentioned position tolerance of watermarks -20- means that distance values -xn-1-, -xn-, -xn + 1-, etc. They show a relatively large fluctuation.

To improve the accuracy of subsequent application steps compared to the use of watermarks -20- as control marks, the positions of two or more watermarks -20- on the endless paper web -10 are detected - and brand positions are calculated that have position deviations lower than those of watermarks -20-.

Said determination of brand positions with lower position deviations can be performed, for example, by calculating the average value of the detected positions. Since banknote paper is generally manufactured using the cylindrical mesh technique, the position of a watermark -20- is repeated approximately with each perimeter of the mesh. Therefore, for the determination of more precise brand positions it is advantageous to determine the average of a multiple of the watermarks -20- for each mesh perimeter. In the exemplary embodiment, approximately m watermarks -20- are found on each perimeter of the mesh and the average of three mesh perimeters is calculated. To calculate the average value, a displacement register is advantageously used, in which the position of a newly detected watermark -xn- respectively replaces the oldest -xn-3m- position detected. Through

image 1

brand positions -yn are then obtained - with position deviations lower than the position deviations of watermarks -20-, since in the calculation their random position deviations are averaged.

In the marking positions -yn- calculated in this way, characteristic marks -22- of color are then created with a contactless procedure, which are used as control marks for the following application steps and

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which, due to their lower position deviations, improve the position accuracy of subsequent application steps.

In order to create said color identification marks -22- the inkjet process has proved especially effective. A generally black identification mark -22-, applied by inkjet printer, can be detected mechanically and suitably by a sensor. In addition, inkjet printers have a very compact construction and, therefore, can be well integrated into existing installations. Applying the identification marks -22- by means of an inkjet procedure also does not require aspiration for smoke or generated fragments. In addition, unlike a through opening, an applied color identification mark cannot impede the stacking of the paper sheets -12- nor cause a hitching of the through openings after the transverse cut.

Since the print head of an inkjet printer has a certain distance to the paper web -10-, in printing, due to the rapid movement of the paper web -10-, the time of Flight of the ink drops depending on the speed of the band.

In another embodiment of the invention, the color identification marks -22- are created by laser marking. For this, it is possible, for example, to incorporate characteristic laser sensitive substances into the paper during papermaking or to apply characteristic laser sensitive substances on the paper web after papermaking. As characteristic substances sensitive to the laser are considered, for example, TiO2, soot particles or infrared absorbers. By means of the laser application, the characteristic substances sensitive to the laser are modified locally, for example, color or blacken.

A special advantage of this variant of the invention is that the laser radiation can pass through the paper web, which allows to simultaneously create identification marks on the front side and the rear side of the paper web in a working step. The identification marks on the front side and the back side are perfectly registered with each other and therefore allow a very precise orientation of the subsequent processing steps, both in the marks of the previous side, as well as in the marks of the side later.

In addition to the contactless procedures mentioned for applying the identification marks -22-, basically other printing procedures such as rotary flexo printing, rotary offset printing or rotary screen printing are also considered.

In an advantageous variant of the invention, the printing of the identification marks -22- takes place in an operation with the printing of a printing feature. In this case, the identification marks -22- can be integrated in the printing tool, so that a perfect registration is achieved with respect to the printing image of the printing feature. For example, an identification mark may be integrated into the printing screen for rotary screen printing. Subsequent applications controlled by the identification mark created in the printing step then have a very good record with respect to the printing images of the printing step.

In general, advantageously, in subsequent applications the positions of the identification marks -22- created are detected and, using the detected positions of the identification marks, each of the paper sheets of the paper band -10 - is provided with at least one through opening. This can be done using a rigid tool such as a rotary punch or a flexible tool, such as a laser cutting installation.

Figure 2 shows a single sheet of paper -12- of the paper strip -10 with watermark -20- and identification mark -22-. Each sheet of paper -12- carries a plurality of individual copies -16- which, in the exemplary embodiment, correspond to the bills cut later. The nominal length of an individual sheet of paper -12- is indicated with -Ls-.

After paper is manufactured, during the subsequent processing of the paper web -10-, the individual copies -16- are provided, in two independent application steps, with two security features that are aligned with each other in the nominal image and complement each other to form a complete characteristic -34-.

In the case of the first safety feature, it is a through opening -30- created by laser radiation or stamped on the sheet of paper -12-. The opening -30- has exactly a straight edge arranged perpendicular to the forward direction -18- of the endless paper web.

In the case of the second safety feature, it is a safety feature applied with a rigid tool, in the example of embodiment of a sheet feature present on an endless sheet strip -32- which is applied on the sheet of paper -12- together with the sheet strip -32-. If the sheet characteristics and the through openings -30- present the nominal positions shown in Figure 2, then they complement each other without distancing each other to form the complete characteristic -34-.

In the exemplary embodiment, to apply the sheet characteristics, the positions of the straight edges contained in the through openings -30- are detected and the current length of a sheet of paper -12- is calculated from the detected positions of the straight songs. Then a strip of sheet -32- is extended with the sheet characteristics to be applied on the paper web -10- depending on the current length of the paper and applied on the web web 5 -10-.

The step of detecting the positions of the straight edges contained in the through openings -30- is explained in detail based on Figure 3.

10 Figure 3 shows an individual copy -16- of a sheet of paper that is provided with a through opening -30-. The opening -30- contains exactly a straight edge -50- arranged perpendicular to the direction of advancement -18- of the endless paper web, which can be scanned by a contrast sensor or transparency sensor. The reference number -60- indicates the display area in which the scanning sensor is active (for example, a contrast sensor or transparency sensor). The scanning sensor detects the

15 straight edge -50- and responds to the registration control for the application of the sheet with registration accuracy. The application with registration accuracy of the sheet can be carried out, in particular, by determining the current length of a sheet of paper from the detected positions of the straight edges -50-, extending a sheet -32- with the safety features to apply on the paper band depending on the current length of the sheet and applying it on the paper band.

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Claims (10)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 1. Procedure for manufacturing an endless paper band (10) for the manufacture of security documents and valuable documents with the procedural steps: a) manufacturing an endless paper web (10) in a cylindrical mesh machine, the paper web (10) being divided into a plurality of equal sheets of paper (12) extending transversely to the longitudinal direction without end (18), and provide at least one sheet of paper (12) for each perimeter of the cylindrical mesh of at least one watermark (20) to control the following processing steps, existing between the positions of the marks of water (20) from the sheets of paper (12) certain position deviations, b) detect the positions of two or more watermarks (20) on the endless paper web (10), c) determine brand positions with smaller position deviations than the position deviations of the watermarks (20) detected, d) create color identification marks (22) at certain mark positions of the paper web (10), e) detect the positions of the identification marks (22) created, f) provide the paper strip (10) with at least one through opening (30) in each of the sheets of paper (12) using the detected positions of the identification marks (22) created, such that each of the through openings (30) have exactly one straight edge (50) arranged perpendicular to the longitudinal direction of the endless paper web (10), g) detect the positions of the straight edges (50) contained in the through openings (30) created, and h) provide the paper web (10) with at least one sheet (32) with safety features to be applied on the paper web (10) on each of the paper sheets (12) using the positions detected in the straight edges (50) contained in the through openings (30) created. 2. Method according to claim 1, characterized in that the identification marks (22) of step d) are created with a contactless procedure. 3. A method according to claim 2, characterized in that the identification marks (22) of step d) are created in an inkjet process and preferably an ink time offset is performed. 4. Method according to claim 2, characterized in that the identification marks (22) of step d) are created by laser marking, such that, preferably in step a), characteristic substances sensitive to the laser are incorporated into the paper or , after papermaking, characteristic substances sensitive to the laser are applied to the paper web (10). 5. Method according to claim 4, characterized in that, by laser marking in step d), identification marks (22) are simultaneously created on the front side and the back side of the paper web. Method according to claim 1, characterized in that the identification marks (22) of step d) are created with a printing method, in particular, by rotary flexography printing, rotary offset printing or rotary screen printing. Method according to at least one of claims 1 to 6, characterized in that in step d) dark identification marks (22) are created, in particular, black. 8. Method according to any one of claims 1 to 7, such that the procedure is performed by a device with - a conveyor device for transporting the endless paper web (10), - a first detection device for detecting the positions of two or more watermarks (20) on the endless paper web (10), - a first evaluation device to determine the positions of the marks with lower position deviations, - a marking device for creating the color identification marks (22) at the determined marking positions of the paper web (10), - a second detection device to detect the positions of identification marks (22) created, - a device for creating the through opening (30) in the paper web (10) using the detected positions of the identification marks (22) created, such that each of the through openings (30) has exactly a straight edge ( 50) arranged perpendicular to the longitudinal direction of the endless paper web (10), - a third detection device for detecting the positions of the straight edges (50) contained in the through openings (30) created, - a device for applying the sheet (32) on the paper band (10) with the safety features to be applied on the paper band (10), using the detected positions of the straight edges (50) contained in the through openings (30) created. Method according to claim 8, characterized in that the third detection device for detecting the positions of the straight edges (50) contained in the through openings (30) created comprises a sensor of 5 contrast or a transparency sensor. Method according to any one of claims 8 or 9, characterized in that the marking device comprises an ink jet printer or a laser engraver.