WO2009027771A1

WO2009027771A1 - Security element particularly for banknotes, security cards and the like

Info

Publication number: WO2009027771A1
Application number: PCT/IB2008/000171
Authority: WO
Inventors: Maurizio Lazzerini
Original assignee: Fabriano Securities S.R.L.
Priority date: 2007-08-28
Filing date: 2008-01-23
Publication date: 2009-03-05
Also published as: SI2183727T1; RU2458404C2; ES2391427T3; EP2183727A1; WO2009027771A8; PL2183727T3; ITMI20071698A1; RU2010111741A; EP2183727B1

Abstract

A security element, particularly for banknotes, security cards and the like, comprising a substrate on which at least one opaque layer (2) is deposited, characters and/or markings (3) being defined in regions of the at least one opaque layer (2), comprising, at least at the characters and/or markings, one or more magnetic elements (4, 6) which are visible at least in transmitted light.

Description

SECURITY ELEMENT PARTICULARLY FOR BANKNOTES, SECURITY CARDS AND THE LIKE Technical field

The present invention relates to a security element particularly for banknotes, security cards and the like, which has a high anti-counterfeiting capability.

Background art

As is known, with the evolution of technology and the diffusion of devices for reproducing graphical elements which are printed or positioned on banknote paper, the need to have security elements which can be inserted at least partially within banknote paper has been, and still is, increasing.

One of the elements that is constantly being developed and researched is the security thread which is normally inserted at least partially within banknote paper. The security thread, through the years, has undergone a constant but significant evolution, and indeed it is still one of the least counterfeited elements, since its counterfeiting is difficult even for expert counterfeiters.

Among security threads, it is possible to identify for example metallic threads with negative text, i.e., threads provided by a backing made of plastics on which at least one layer of metal is arranged; characters, lettering and the like being formed in said metal layer by total removal of the metal at the regions of the characters and/or lettering. EP 319 157 discloses the technique mentioned above.

A thread is also known, for example, in which, in order to increase the security characteristics, at least one full-surface layer is added which therefore covers both the regions without metal and the metallic regions with ink which has fluorescent properties.

There are other types of threads in which discontinuities of the metal are inserted between blocks of letters so that the conductivity can be detected in certain and known lengths. However, the marketing of transferable metalized stripes has caused all these threads to undergo significant counterfeiting, which has led to the need to provide a partially demetallized thread, which therefore entails leaving in the characters a small amount of metal, such that it can be detected by suitable laboratory devices. Therefore, in this last type of threads, the characters are only partially demetallized. Patent applications WO2004/014665 and WO2004/098900 relate to so-called partially demetallized threads.

There are also types of threads which can be detected also by means of magnetic sensors. EP 516 790 discloses a thread in which detectable magnetic regions are inserted between the letters formed by performing a total demetallization, so that the thread can therefore be detected both as conductive (due to the presence of metal deposited in continuous form) and by means of magnetic sensors (by virtue of the magnetic elements arranged above or below the layer of metal, but never inside the letters). Therefore, EP 516 790 discloses a security device in which the characters or letters are completely demetallized.

However, even security threads with magnetic regions inserted between the letters, but not within the regions or areas that define the letters, have been counterfeited, again by using the transfer technique. It is in fact possible to provide a stripe which has characters in negative form by using metallic transfers onto which elements which are magnetic, either in a continuous form or a discontinuous form in order to create magnetic codes, are subsequently transferred between the blocks of letters. To provide industrially a thread of the type cited above it is sufficient to have a rotary press with a plurality of printing sections as described above also in EP 516 790, printing on a transparent material (generally polyester) printed elements with removable inks, performing vacuum metalization on the full surface so as to cover the removable inks, removing the inks and consequently also the metal that covers them, then leaving printed elements which are identical to the ones printed with removable inks, and then printing with magnetic inks continuous or discontinuous areas in the regions which have not been demetallized and are therefore adjacent to the demetallized regions. In this manner, the presence of magnetic elements is not visible with ordinary viewing instruments (naked eye, optical magnifiers, et cetera), since they are always covered by metal. The magnetic elements are visible exclusively with suitable devices dedicated to detection of magnetism.

Disclosure of the Invention

The aim of the present invention is to provide a security element, particularly for banknotes, security cards and the like, which has magnetic elements at least in the regions without metal, said magnetic elements being visible by means of a normal magnifying lens.

Within this aim, an object of the present invention is to provide a security element, particularly for banknotes, security cards and the like, in which said magnetic elements are visible in the regions without metal at least in transmitted light, by using a normal magnifying lens.

Another object of the present invention is to provide a security element in which the magnetic elements can be detected even by devices for detecting magnetic properties. Still another object of the present invention is to provide a security element for which counterfeiting is even more difficult than for known types of security elements.

This aim and these and other objects, which will become better apparent hereinafter, are achieved by a security element, particularly for banknotes, security cards and the like, comprising a substrate on which at least one opaque layer is deposited, characters and/or markings being defined in regions of said at least one opaque layer, characterized in that it comprises, at least at said characters and/or markings, one or more magnetic elements which are visible at least in transmitted light. Brief Description of the Drawings Further characteristics and advantages of the invention will become better apparent from the description of preferred but not exclusive embodiments of the security element according to the present invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a view of a first embodiment of the security element according to the present invention;

Figure 2 is a view of a second embodiment of the security element according to the present invention; Figure 3 is a view of a third embodiment of the security element according to the present invention;

Figure 4 is a view of a fourth embodiment of the security element according to the present invention;

Figure 5 is a view of a fifth embodiment of the security element according to the present invention;

Figure 6 is a view of a sixth embodiment of the security element according to the present invention;

Figure 7 is a view of a seventh embodiment of the security element according to the present invention; Figure 8 is a view of an eighth embodiment of the security element according to the present invention;

Figure 9 is a view of a ninth embodiment of the security element according to the present invention;

Figure 10 is a view of a tenth embodiment of the security element according to the present invention. Ways of carrying out the invention

With reference to the figures, the security element according to the present invention is as follows.

It is noted beforehand that the expression "security element" is used to reference a security thread, stripe or patch, to be applied or inserted at least partially in paper for banknotes or security documents, such as passports, or in plastics such as PVC, PET, et cetera, for credit cards.

The security element according to the invention is generally designated by the reference numeral 1. In all Figures 1 to 10, identical reference numerals designate identical elements.

First of all, there is a substrate made of plastics, such as polyester, which is not shown explicitly in the figures, since such figures show the security thread in plan view; at least one opaque layer, conveniently for example a layer of metal such as aluminum, nickel, silver, et cetera, is deposited on such substrate, for example by vacuum deposition on the full surface.

A so-called "resist" ink based on nitrocellulose is printed on this layer of metal, which is designated by the reference numeral 2, and allows to preserve the metal deposited in vacuum against subsequent etching, performed for example with acid, for example 52% phosphoric acid at 50⁰C for a speed of 40 m/min with an immersion path which is 23 m long, or with 0.8-1% soda with a temperature and a speed which are similar to the acid.

Etching with acid allows to remove the metal in the areas in which the resist is not printed. The resist is not printed normally in the areas that correspond to characters or markings 3 defined on the security element.

It should be noted that the metal layer 2 can be removed completely from the areas in which the characters 3 are defined, so as to have the inside of the characters fully transparent, or can be removed only partially, obtaining therefore a reduction in the thickness of the layer of metal 2, as shown for example in Figures 6 to 10.

The only partial removal of the layer of metal at the areas of the characters allows printed elements to be visible when viewed in transmitted light. The printed elements, i.e., characters, lettering and the like, can be either negative or positive. The metal can be deposited in vacuum by means of vaporization machines or can be transferred either hot or cold, or, skipping the metalization and demetallization steps, printed with inks and pigments which are metallic or have a metallic effect. The peculiarity of the invention consists in that it provides, on a security element provided as described above, according to the background art, for the presence of at least one magnetic element which is arranged at least within the printed elements which are totally or partially without metal.

In particular, Figures 1 to 5 illustrate a situation in which the characters, designated by the reference numeral 3, are fully demetallized, and magnetic elements, designated by the reference numerals 4 and 6, are provided inside them, while Figures 6 to 10 illustrate the situation in which the characters are demetallized only partially and are obtained by reducing the thickness of the metal, and are designated in this case by the reference numeral 8.

In any case, the embodiments of Figures 1 to 5 are repeated mirror- symmetrically in the embodiments of Figures 6 to 10, with the only difference that in the first five figures the characters that are present on the security thread are totally demetallized, whereas in the second five figures the characters are demetallized only partially. Figures 1 to 5 apply also to embodiments in which the characters are obtained from negative prints of metallic or metallic-effect inks.

The methods for positioning the magnetic elements, designated by the reference numeral 4 and by the reference numeral 6 in the various figures, as will be described in detail hereinafter, are several.

For example, it is possible to provide the resist ink described above with resins which are sensitive to bases, i.e. resins which protect the metal against acid etchings such as phosphoric acid, which can then be removed for example by means of a bath in sodium carbonate with 1% dilution (pH 12) at 50⁰C at a rate of 40 m/min with a path of immersion of the security element of approximately 23 meters.

With the type of inks described above it is possible to provide a security element or thread by using therefore, as mentioned above, a backing made of plastics, such as polyester for example, on which, by vacuum deposition, the layer of metal such as aluminum, nickel, silver, et cetera is then deposited on the full surface.

A protective resist is then printed onto the layer of material thus provided, as described earlier, and allows to protect the metal against acid etchings and to leave free the unprotected regions, so that the metal can be removed totally or partially in order to provide characters which are totally or partially demetallized.

Once the metal has been removed, by using magnetic inks provided for example with suitably treated iron oxides, as regards both particle size distribution, which must be the finest possible (generally a magnetic ink contains particles with a size of around 4-5 μm, while in the present invention it is useful for said size to be for example less than 2 μm), and for the resin, which must have a great capacity to grip the polyester and the metal and/or the resist which is printed to define the printed elements.

With the magnetic inks described above it is possible to print extremely small areas, for example dots measuring 30-40-50 μm in diameter, which allow in any case excellent readability of the printed elements obtained by demetallizing totally or partially the areas that correspond to the printed elements, and at the same time allow the assigned personnel to view them by using a magnifying lens. The magnetic dots, which can also be bands, lines or the like, designated by the reference numerals 4 and 6, as described earlier, can be provided both within the regions that define the characters and outside them, as described in detail hereinafter.

Once the dots, lines or any other shape of the magnetic element have been printed, this is followed by a step for removing the resist, which therefore removes also the dots printed over the resist, leaving instead intact the dots in the regions where the resist has not been printed.

The security element can thus be finished by coupling it to another layer of polyester and with the addition of a hot-melt external adhesive for anchoring to the fibers of the paper within which the security element will have to be positioned.

A second method which can be used to provide the security element according to the invention entails printing the magnetic dots or in any case the magnetic elements both on the resist with nitrocellulose resin, used in the demetallization step, and inside the printed elements with partial or total absence of metal.

In this case, it is possible to overprint or apply over the metallic part an additional layer of ink or metal, so as to reduce as much as possible the view of the magnetic dots above the metal. In order to provide the security element according to the invention, it is convenient to provide inks which contain iron oxide particles for example wrapped by resins which protect the oxide and at the same time do not allow a corrosive action thereof on the metal onto which these inks must be deposited, and at the same time allow optimum anchoring in the regions where the metal is not present.

The method used in the invention provides, as a solution, spreading onto the polyester substrate, before metalization, a primer which is based only on nitrocellulose in infinitesimal amounts, so that once the metal has been removed in the demetallization process, the regions that remain without metal have an optimum predisposition for anchoring with the magnetic ink which is deposited subsequently.

As mentioned earlier, the magnetic elements or magnetic areas that are printed in the regions which lack metal completely or partially can have any shape, such as for example a thin line, or a series of thin lines, or a series of dots, all these elements with mutually identical or different widths and spacings.

A further process for providing the invention entails providing a film made of plastics such as polyester onto which a layer of aluminum is applied on the full surface by vaporisation in vacuum, and printing thereon the resist with the printed elements in which the metal is to be removed totally or partially by chemical removal as mentioned earlier. At this point, therefore, one obtains a plastic film which has printed elements which are legible in transmitted light and inside which there may be a complete absence of metal or there may be such an amount as to allow in any case its legibility in transmitted light. It is further evident that the metal inside the printed elements can have remained there by partial reduction of the original thickness or by total removal in a first chemical pass to then return to deposit a minimal amount thereof with a second pass in a metalization machine. A second film is prepared starting again from a backing made of plastics such as polyester, on which metallic or metallic-effect inks can be printed for preparation to receive magnetic inks; in this case, instead of the metallic inks it is possible to use previously demetallized regions. On a film thus provided, the dots with magnetic ink are printed and, if necessary, so are other magnetic regions as well, which can form various types of codes, as explained in greater detail hereinafter. Both the dots and the magnetic regions must be printed so that with a further pass it is possible to couple the two films, one of which is metalized and demetallized and the other one is printed with magnetic inks on metallic inks and/or on metal. If the coupled product is viewed carefully, one finds printed elements which are legible in transmitted light and have inside them dots provided with magnetic inks and around them, either alternately or adjacent or parallel to the printed elements, other magnetic regions which however are invisible in reflected light and transmitted light because they are covered by metalized areas or inks. The aim of the invention is to obtain areas with magnetic properties which are suitable both to be detected simply with a magnifying lens and to be detected by dedicated devices with manual, semiautomatic and automatic transport.

Generally, the use of manual transport allows to detect the magnetic signals more easily, since there is no contamination caused by background

"electrical noise" generated for example by motors for automatic transport, and also because it is possible to select locations where electromagnetic fields which may interfere with reading do not already exist in the air.

When using semiautomatic or automatic devices, it is always possible to select the location suitable for reading and therefore the magnetic signals must be such as to overcome the normal noise which may occur in workplaces where reading is performed. Therefore, the amount of magnetic oxide introduced in the magnetic ink must be such as to have, for example, at least a residual magnetism of 100 nWm and a coercivity of more than 100 oe.

Of course, the values indicated above are merely examples, since they refer to the sensitivity of currently available low-cost detection devices. As technologies advance and such devices improve, considerably lower values may be provided. The areas with magnetic properties described above, which are present at least in the regions without metal, i.e., at the regions of the characters, or at the regions of the characters and outside them, may be provided with a plurality of types of magnetic inks, i.e., inks with different coercivities and identical residual magnetism, or with different coercivities and a different residual magnetism, or with identical coercivities and different residual magnetism, or with identical coercivities and identical residual magnetism, which can be printed or deposited alternately or side- by-side between the regions without metal and the regions with metal, and be printed or deposited alternately or side-by-side over each other. The different coercivity of the inks can be achieved both by means of different oxides and by means of mixtures among them. The different residual magnetism can be obtained by varying the percentage of different oxide within the ink and by using identical areas, identical inks but different thicknesses. In this manner, it is possible to provide magnetic areas which give rise to magnetic codes of the type with identical thickness but different areas separated by identical or different spaces, or of the type with identical areas and different thicknesses, or of the type with identical areas with identical coercivity but with different residual magnetism, or of the type with different coercivity and identical residual magnetism, et cetera, as defined above.

The magnetic areas described above can be provided so as to obtain magnetic elements in the regions without metal, with different magnetic and colorimetric intensity depending on whether the dots are in the regions without metal or in the adjacent regions, i.e., regions below or above the metal. The different magnetic intensity can be noticed by observing the magnetic dots superimposed on the demarcation line between the regions with metal and the regions without metal. To do this, the magnetic dots are printed over the nitrocellulose-based resist, which is used to preserve the metal from the regions in which the metal must be removed. The ink used to print the dots can be provided conveniently for example by means of nitrocellulose resins in an amount of approximately 50% of the dry product, the remaining 50% being necessarily composed of magnetic material.

An ink of the type described above allows, during treatment in acid, to be etched chemically more where the areas are extremely small (for example dots) and arranged directly on metal and not on the resist, thus creating the conditions for a decrease in quantity and therefore greater transparency and a different magnetic signal. Moreover, the magnetic elements can be provided so as to obtain a reduction in the area of the dots arranged in the regions without metal, so that with a normal magnifying lens it is possible to notice the difference in area between the dots located in the regions without metal and the dots located in the regions with metal, i.e., adjacent to the characters.

The various figures are now described, pointing out the differences among the different embodiments.

In Figure 1, the magnetic elements 4 are provided exclusively within the areas of the characters 3 which are fully demetallized.

The second embodiment, shown in Figure 2, provides for the deposition of magnetic elements also in the regions where the metal is present, i.e., the regions adjacent to the characters 3, which in this case also are completely demetallized. Such additional magnetic elements, arranged above or below said at least one metalized layer, are arranged on the two edges of the security element continuously or alternately.

Figure 3 is a view of the third embodiment, in which the magnetic elements, designated by the reference numeral 5, have a smaller area than the magnetic elements 4 arranged outside the characters.

Therefore, in this third embodiment, the characters 3 are fully demetallized and the magnetic elements 5 contained therein have a smaller area than the magnetic elements 4 that lie outside the characters and therefore on the metalized surface.

In the fourth embodiment of Figure 4, instead, the magnetic elements, designated by the reference numeral 6, have a different thickness with respect to the magnetic elements 4 that are provided outside the characters. Therefore, in the fourth embodiment the magnetic elements 6 that are present within the characters, which are fully demetallized, have a different thickness with respect to the magnetic elements 4 that are present in the regions adjacent to the characters, i.e., above the metal layer.

The fifth embodiment has as a difference the presence of magnetic regions outside the areas that define the characters, where such regions are designated by the reference numeral 7, and are therefore arranged above the metalization layer 2.

Figures 6 to 10, as mentioned earlier, are absolutely similar to Figures 1 to 5, with the difference that the characters, now designated by the reference numeral 8, are demetallized only partially, and therefore the embodiments of Figures 1 to 5 correspond respectively to Figures 6 to 10, except indeed for the fact that the characters are partially and not totally demetallized.

The presence of the magnetic elements defined above can be combined with other characteristics of security elements, such as for example holography, which can be provided on the metallic or nonmetallic regions or on both or by using polyester films on which, by means of vaporization systems, materials are deposited such as chromium, magnesium fluoride, silicon or aluminum oxide, used commonly to provide films with color-shifting characteristics depending on the angle of incidence with which they are struck by the light and viewed.

The change of color of the metallic layer can be determined by two different metals such as aluminum, copper, or again copper, gold, et cetera. Going back to the concept of color variation, reference is made to the so- called "color shift" effect, which is obtained by depositing in vacuum materials such as magnesium fluorides, chromium, aluminum oxides, silicon, et cetera, the color result of which changes depending on the inclination with which they are struck by the light and by the angle of reflection. Two of the most widely used colors are magenta, when viewing the film by aligning it axially with the viewpoint of the observer, becoming green when the film is inclined at 60°.

It is further possible to provide fluorescent inks which can be provided in the metallic regions and in the regions without metal or also on both.

In practice it has been found that the security element according to the invention fully achieves the intended aim and objects, since it allows to have magnetic regions at the characters which are totally or partially metalized and also optionally outside said characters, which therefore constitute an additional element of difficulty for any counterfeiting of the security element. Moreover, the magnetic elements thus defined have the advantage of being detectable directly by means of a simple magnifying lens, thus facilitating verification of the authenticity of the documents in which the security element according to the invention is inserted even by non-expert people. The security element thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.

Thus, for example, when describing the coercivity of the magnetic elements, and in particular the possibility to use different types of magnetic inks, the difference in coercivity should be for example at least 15%, while the difference in residual magnetism should be for example at least 10%.

Moreover, the metallic parts of the security element can be, as mentioned, fluorescent and therefore visible when excited by ultraviolet rays, or also the nonmetallic parts can be covered entirely by inks or pigments with fluorescent characteristics, or the metallic parts can have dichroic characteristics.

Moreover, the invention also relates to a system for reading a security element as defined above, comprising means which are adapted to identify the placement of magnetic elements arranged above or below the at least one metalized layer, when the magnetic elements are deposited on the edges of the security element.

Moreover, the system comprises means adapted to identify the presence of magnetic inks with a different coercivity of the magnetic elements arranged above or below the metalized layer, when the magnetic elements are deposited on the edges of the security element by using the different residual magnetism obtained by rotating the magnetic orientation of the magnetic elements that are printed with a lower coercivity than magnetic elements with a higher coercivity (for example 300 oe for the low- coercivity elements and 3500 oe for the high-coercivity elements). All the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements and to the state of the art. The disclosures in Italian Patent Application no. MI2007A001698, from which this application claims priority, are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A security element, particularly for banknotes, security cards and the like, comprising a substrate on which at least one opaque layer is deposited, characters and/or markings being defined in regions of said at least one opaque layer, characterized in that it comprises, at least at said characters and/or markings, one or more magnetic elements which are visible at least in transmitted light.

2. The security element according to claim 1, characterized in that said at least one opaque layer is a metalized layer.

3. The security element according to claim 2, characterized in that said characters and/or markings are defined by at least partially demetallized areas of said metallized layer.

4. The security element according to one or more of the preceding claims, characterized in that said metallized layer is provided by printing with metallic inks or with inks which have a metallic effect.

5. The security element according to claim 1, characterized in that said magnetic elements can be detected in transmitted light by using a magnifying lens.

6. The security element according to one or more of the preceding claims, characterized in that said magnetic elements can be detected by devices for detecting magnetic properties.

7. The security element according to one or more of the preceding claims, characterized in that said magnetic elements are provided by magnetic inks.

8. The security element according to one or more of the preceding claims, characterized in that said magnetic elements are present also in regions which are adjacent to said characters and/or markings, above or below said at least one metalized layer.

9. The security element according to one or more of the preceding claims, characterized in that said magnetic elements arranged in the at least partially demetallized areas are arranged side by side with respect to additional magnetic elements which are arranged above or below said at least one metalized layer.

10. The security element according to one or more of the preceding claims, characterized in that said additional magnetic elements arranged above or below said at least one metalized layer are arranged on the two edges of the security element continuously or alternately.

11. The security element according to one or more of the preceding claims, characterized in that said magnetic elements are point-like elements arranged sequentially along an axis which is parallel to the side of the security element.

12. The security element according to one or more of the preceding claims, characterized in that said magnetic elements arranged within said at least partially demetallized areas or in the areas above or below said at least one metalized layer have mutually identical coercivity and residual magnetism.

13. The security element according to one or more of the preceding claims, characterized in that said magnetic elements arranged in the at least partially demetallized areas or in the areas above or below said at least one metalized layer have mutually identical coercivity and mutually different residual magnetism.

14. The security element according to one or more of the preceding claims, wherein said magnetic elements arranged in the at least partially demetallized areas or in the regions above or below said at least one metalized layer have mutually different coercivity and mutually identical residual magnetism.

15. The security element according to one or more of the preceding claims, characterized in that said magnetic elements that are present in said at least partially demetallized areas have an area that is smaller than the magnetic elements arranged above or below said at least one metalized layer, outside said at least partially demetallized areas.

16. The security element according to one or more of the preceding claims, characterized in that said magnetic elements arranged within said at least partially demetallized areas have a lower colorimetric intensity than the magnetic elements arranged in the areas above or below said at least one metalized layer.

17. The security element according to one or more of the preceding claims, characterized in that it has, in addition to the presence of said magnetic elements within said at least partially demetallized areas, and above or below at least one metalized layer, continuous magnetic regions which are arranged adjacent to point-like magnetic regions.

18. The security element according to one or more of the preceding claims, characterized in that said magnetic elements generate a magnetic code which is a result of the lengths of the magnetic areas and of the adjacent interspaces.

19. The security element according to one or more of the preceding claims, characterized in that the metallic and nonmetallic parts of said security element are holographic.

20. The security element according to one or more of the preceding claims, characterized in that said at least one metalized layer is provided so as to obtain a color-shift effect when said layer is viewed at different angles.

21. The security element according to claim 20, characterized in that said metalized layer is provided by means of two different metals.

22. The security element according to one or more of the preceding claims, characterized in that it is covered with ink or pigment having fluorescent characteristics.

23. The security element according to one or more of the preceding claims, characterized in that said at least one metalized layer has dichroic characteristics.

24. The security element according to one or more of the preceding claims, characterized in that said magnetic elements that are present in said at least partially demetallized areas have a lower thickness than said magnetic elements that are present above or below said at least one metalized layer.

25. The security element according to one or more of the preceding claims, characterized in that said areas which define said characters and/or markings are totally demetallized.

26. The security element according to one or more of the preceding claims, characterized in that it is a security thread which is adapted to be inserted at least partially in paper for banknotes.

27. A security document, characterized in that it comprises at least one security element according to one or more of claims 1 to 26.

28. A method for providing a security element according to one or more of claims 1 to 26, comprising the steps that consist in: starting from a substrate made of plastics, depositing at least one metalized layer; printing a resist ink on said metalized layer; removing at least partially metal at the areas where said resist ink is not printed, in order to define characters and/or markings, in which said metal is at least partially removed; characterized in that said resist ink is provided by means of resins which are sensitive to basic elements and are adapted to protect the metal against acid etchings but can be removed subsequently by means of basic elements; said metal removal step being followed by a step which consists in printing magnetic areas, and removing said resist ink in order to leave said magnetic elements in regions where said resist ink has not been printed.

29. The method according to claim 28, characterized in that it comprises a step which consists, after printing said magnetic elements both over said resist ink and within said at least partially demetallized areas, in overprinting an additional layer of ink or metal, in order to reduce as much as possible the view of said magnetic elements above said metal.

30. A method for providing a security element according to one or more of claims 1 to 26, comprising the steps that consist in: providing a first film made of plastics, or which at least one opaque layer is arranged, printed elements being defined on said opaque layer; coupling in register said first film made of plastics with a second film provided with magnetic elements.

31. The method according to claim 29, characterized in that said at least one opaque layer is provided by metalization of said film of plastics.

32. The method according to claim 30, characterized in that said printed elements are provided by at least partial demetallization of said metalization layer.

33. The method according to one or more of claims 29 to 31, characterized in that said printed elements are provided by total demetallization of said metalization layer and subsequent partial remetallization.

34. The method according to one or more of claims 29 to 32, characterized in that said printed elements are provided by a microprinting process.

35. The method according to one or more of claims 30 to 34, characterized in that said printed elements are provided by means of an amount of metal which is adapted to allow their viewing in transmitted light and is sufficient to allow their detection in a laboratory by means of devices for detecting the presence of metal.

36. A system for reading a security element provided according to one or more of claims 1 to 26, characterized in that it comprises means adapted to identify the position of magnetic elements arranged above or below said at least one metalized layer when said magnetic elements are deposited on the edges of said security element.

37. A system for reading a security element provided according to one or more of claims 1 to 26, characterized in that it comprises means adapted to identify the presence of magnetic inks with different coercivity of the magnetic elements arranged above or below said metallized layer, when said magnetic elements are deposited on the edges of said security element by using the different residual magnetism obtained by rotating the magnetic orientation of the magnetic elements printed with lower coercivity than magnetic elements of higher coercivity.