Method for producing a security feature on a security paper and use

Description

[0001] The invention relates to a method for producing a security feature on a security paper and its use. background

[0002] Security paper is used to produce banknotes, but also for passports, identity cards, credit cards, check forms, securities, postage stamps, and the like. The security papers for various products differ, for example, in the requirements for the paper's durability. Security paper can be custom-made but is also available as pre-produced commercial goods in various forms.

[0003] Security paper provides protection against counterfeiting. For this purpose, the security paper is regularly provided with security features after it is produced.

[0004] For example, raw material combinations containing cotton or bleached pulp are used for the production of security paper, with the cotton content being 90% or more.

[0005] Document WO 2011 / 006897 A2 describes a device for applying an ink to a substrate web guided past the device along a travel direction. The device is characterized in that it has a surface area that is convex in the travel direction and straight perpendicular to the travel direction, which can be brought into contact with the substrate web, and in that in the convex surface area there are one, preferably at least two passage openings for the ink that can be separately controlled with ink and offset in a direction perpendicular to the travel direction, through which the ink is applied directly to the substrate web, wherein the application rate of the ink depends on the angle of incidence between the plane of the substrate web and the normal to a tangential plane on the surface area at the location of the respective passage opening.

[0006] Document EP 0 659 935 A2 discloses a method for providing securities with authenticity features, in which a homogeneous mixture of a feature substance in powder form and a gas in a defined concentration is produced. This mixture is ejected at high speed from at least one nozzle arranged at a predetermined distance from the paper web and transferred to the moving paper web.

[0007] The document DE 198 60 093 A1 relates to a value document with a first machine-verifiable physical or chemical property and with a second machine-verifiable physical or chemical property, wherein the first and second verifiable properties can be machine-verified separately from one another, the value document loses the first verifiable property at a first temperature, and the value document loses the second verifiable property at a second temperature which is different from the first temperature.

[0008] The document WO 2005 / 061794 A1 describes a security paper for producing value documents with a flat substrate which is at least partially provided with a coating, wherein the coating contains pyrogenic titanium dioxide and at least one binder. Summary

[0009] The object of the invention is to provide a method for producing a security feature on a security paper, which enables the formation of the security feature in various designs in a simple and efficient manner.

[0010] To achieve this objective, a method for producing a security feature on a security paper according to independent claim 1 is provided. Furthermore, the use of the produced security paper is provided. Further embodiments are the subject of dependent subclaims.

[0011] According to one aspect, a method for producing a security feature on a security paper is provided, in which a security paper is produced by means of a papermaking process, and a colored security feature is formed on the security paper. To form the colored security feature during the papermaking process in a paper machine, a dye is applied at least locally to a pressed and pre-dried, not yet completely dried, intermediate product of the security paper by means of a dye application process, while a scooped paper mass forming the intermediate product is arranged on a drying device. The intermediate product is then further dried to produce the security paper.

[0012] According to a further aspect, the use of the produced security paper with security feature is provided for producing a security document, such that a security feature of the security document is formed with the security feature of the security paper.

[0013] According to the proposed technology, the colored security feature is formed during the production of the security paper, making it possible to produce security paper that already has the colored security feature. The security paper thus produced can then be used to produce a security document in which the colored security feature created during paper production forms a document security feature. Optionally, the produced security paper can then be equipped with additional security features, as are known in various embodiments.

[0014] The dye is applied to create the colored security feature during the papermaking process, embedded in the drying process, before the paper fibers are finally dried in the paper machine and the paper is removed, especially before it can be rolled up. Typically, the paper fibers are formed into a continuous paper web in the paper machine. The local dye application takes place before the continuous paper web is finally dried.

[0015] In this way, security paper is produced and made available for subsequent use, which already has the individually designed color security feature.

[0016] The dye can be applied using a non-contact inking process. With non-contact inking processes, there is no contact between the inking device and the not yet completely dried intermediate product for the security paper.

[0017] The dye can be sprayed using a non-contact ink application process. For example, the inkjet printing process can be used. This can involve a narrow line of ink jet. Alternatively or additionally, a wide ink jet can be used to spray the entire surface or part of the surface.

[0018] The dye can at least partially run after application to the intermediate product. Due to the wetness or moisture of the intermediate product, in this embodiment, the applied dye partially runs, which can be used to specifically customize the colored security feature by utilizing different levels of running during the manufacturing process for different security features, for example, by varying the wetness or moisture level of the intermediate product to which the dye is applied.

[0019] The dye is applied while a scooped paper stock, forming the intermediate product, is placed on a drying device. The paper stock can be placed on a screen device that assists in the drainage or removal of moisture from the scooped paper stock. The drying device can be part of a paper machine consisting of several sections for different process steps. For example, one or more of the following sections can be provided: headbox, screen / former section, press section, pre-drying section, cloth press, after-drying section, and reeling. Different types of paper machines can be used, for example, fourdrinier, cylinder, or inclined screen machines, which differ according to the type of sheet formation system.

[0020] The dye can be applied to one or both sides of the intermediate product, creating a color security feature on one or both sides. The dye can be applied to one or both sides in localized areas, meaning it doesn't completely cover the surface of the intermediate product on one or both sides.

[0021] The dye is applied to a pre-dried intermediate product. The dye is applied after a pre-dried intermediate product has been obtained. This takes place in the paper machine after the fiber pulp has been pressed and pre-dried, i.e., after it still has a moisture content. By applying the dye to the pre-dried intermediate product, it can be prevented that the dye completely penetrates the paper pulp. Volume areas of the paper pulp can remain free of the dye. For example, the paper pulp can be dried on one side using a drying device, such as a fan, and the dye can be applied to an opposite, not yet dried, side, whereby only a local or limited distribution of the dye can be achieved.Applying the dye to the pre-dried intermediate product can, in particular, enable and / or ensure controllable application to only one side of the intermediate product. The degree of pre-drying can be used to adjust the moisture content of the intermediate product. This can, in particular, make it possible to control the degree of bleeding of the applied dye. This can also control the individual formation of the colored security feature.

[0022] The pre-dried intermediate product can be pre-dried to an extent of at least 50 volume percent of the total volume of the paper pulp, i.e. at least half.

[0023] The dye may be applied to a pre-dried intermediate product, on one or both sides, which is pre-dried on the opposite flat sides of the paper pulp, but not in a central area between the dried flat sides.

[0024] The dye can be applied to a dried portion of the pre-dried intermediate product. A non-pre-dried portion of the pre-dried intermediate product can remain free of the dye. A reverse embodiment can also be provided, in which the dye is applied directly to the non-pre-dried portion of the pre-dried intermediate product, while the dried portion remains free of the dye.

[0025] The dye can be applied while the intermediate product is being dried. In this embodiment, the at least local application of the dye by means of the dye application process is carried out at least partially while the intermediate product is simultaneously (further) dried.

[0026] The dye can be applied to the intermediate product, covering at least one side of the entire surface.

[0027] The color security feature can be applied to the intermediate product as a color pattern. The color pattern can include locally formed stripes, dots, circles, triangles, or the like. Combinations of the various basic geometric shapes are also possible.

[0028] The security paper with the colored security feature can be used for various security documents, such as banknotes, passports, identity cards, credit cards, check forms, securities, postage stamps or the like. Description of implementation examples

[0029] Further embodiments are explained in more detail below with reference to the figures of a drawing. Herein: Fig. 1 a schematic representation of a sub-process of the production of a security paper and Fig. 2 a schematic representation of sections of a security paper with a colored security feature.

[0030] Fig. 1shows a schematic representation of the production of a security paper 1, which passes through various sections or stations 3.1, ..., 3.n in a paper machine 2. In the paper machine 2, a paper web is formed from paper fibers. The sections 3.1, ..., 3.n include, for example, the following sections: headbox, wire / former section, press section, pre-drying section, linen press, after-drying section, and reeling. Manufacturing processes for security paper are known in various forms.

[0031] Using a dye application device 4, an intermediate product 5 is provided at least locally with a colored security feature by applying the dye without contact. The intermediate product 5 is then (further) dried.

[0032] Fig. 2 shows various versions of the security paper with colored security features 6. Alternatively to the Fig. 2 In the embodiment shown, it can be provided that the security paper is coated with a dye over one side of the entire surface during production. In the various embodiments, the applied dye can run along edges 7 of the security paper 1 due to the moisture or wetness content of the intermediate product 5.

[0033] The features disclosed in the above description, the claims and the drawings may be important for the realization of the various embodiments both individually and in any combination. List of reference symbols

[0034] 1Security paper 2Paper machine 3.1, ..., 3.nStations of the paper machine 4Ink application device 5Intermediate product 6Color security feature 7Edges

Claims

1. A method for producing a security feature on security paper, in which - a security paper (1) is produced by means of a papermaking process and - during this process, a coloured security feature (6) is formed on the security paper (1), wherein, in order to form the coloured security feature (6), during the papermaking process in a paper machine, a dye is applied at least locally to a pressed and pre-dried, but not yet finally dried, intermediate product (5) of the security paper by means of a dye application method, while a formed paper pulp providing the intermediate product (5) is arranged on a drying device and the intermediate product (5) is subsequently further dried.

2. The method according to claim 1, characterized in that the dye is applied by means of a contactless dye application method.

3. The method according to claim 2, characterized in that the dye is sprayed on during the contactless dye application method.

4. The method according to at least one of the preceding claims, characterized in that the dye at least partially spreads after being applied to the intermediate product (5).

5. The method according to at least one of the preceding claims, characterized in that the dye is applied to one or both sides of the intermediate product (5).

6. The method according to any one of the preceding claims, characterized in that the dye is applied to a dried section of the pre-dried intermediate product (5) and an non-pre-dried section of the pre-dried intermediate product (5) remains free of dye.

7. The method according to any one of the preceding claims, characterized in that the dye is applied while the intermediate product (5) is being dried.

8. The method according to at least one of the preceding claims, characterized in that the dye is applied to at least one side of the intermediate product (5) covering its entire surface.

9. The method according to at least one of the preceding claims, characterized in that the coloured security feature (6) is applied to the intermediate product (5) in the form of a colour pattern.

10. Use of a security paper with a security feature produced according to at least one of the preceding claims for producing a security document, in such a manner that the security feature (6) of the security paper (1) forms a security feature of the security document.