TW202543902A - Transferring device and method for producing n security documents - Google Patents

Abstract

Transferring device and method for producing N security documentsA transferring device (100) for orienting platelet-shaped magnetic or magnetizable pigment particles contained in a radiation curable coating composition (200) and applied on a substrate (S), the transferring device (100) comprising:a number N of identical magnetic blocks (102) aligned along an alignment line (103) provided on an outer surface of the transferring device (100), the magnetic blocks (102) each including M magnetic field generating devices (101) each generating a corresponding magnetic field such that the magnetic blocks (102) each generate a block magnetic field, N being greater than or equal to two, and M being greater than or equal to one; anda shielding element (105) partly isolating the block magnetic field of each magnetic block (102) from the block magnetic field of the other magnetic blocks (102), or a compensation magnetic block (106) provided alongside the magnetic block (102).

Description

Transmission device and method for generating N secure files

This invention relates to a conveying device for orienting sheet-like magnetic or magnetizable pigment particles. Further, this invention relates to a magnetic orientation unit for this conveying device, a printing press including such a conveying device, and a method for generating N security documents.

In this art, it is known, for example, to use inks, compositions, coatings, or layers containing oriented magnetic or magnetizable pigment particles, particularly optically variable magnetic or magnetizable pigment particles, to create security elements in the field of secure documents. For example, coatings or layers containing oriented magnetic or magnetizable pigment particles are disclosed in US 2,570,856; US 3,676,273; US 3,791,864; US 5,630,877 and US 5,364,689. For example, WO 2002/090002 A2 discloses coatings or layers containing oriented magnetic color-shifting pigment particles that produce particularly attractive optical effects and can be used to protect secure documents.

Magnetic or magnetizable pigment particles in printing inks or coatings allow for the creation of magnetically induced images, designs, and/or patterns by applying a corresponding magnetic field, thereby causing localized orientation of the magnetic or magnetizable pigment particles in the uncured coating, followed by curing the coating. The result is a fixed magnetically induced image, design, or pattern (referred to in this technique as an optical effect layer (OEL)). In this way, magnetically induced patterns with strong resistance to forgery can be produced. The security element discussed can only be generated using both: magnetic or magnetizable pigment particles or corresponding ink, and specific techniques for printing the ink and orienting the pigment within the ink.

The aforementioned optical effect layer (OEL) is typically obtained using a printing press, which transports a substrate printed with the OEL and includes sections for: (a) applying an ink, composition, coating, or layer containing magnetic or magnetizable pigment particles onto the substrate; (b) orienting the magnetic or magnetizable pigment particles using a magnetic field; and (c) curing the ink, composition, coating, or layer containing the oriented magnetic or magnetizable pigment particles. To orient the magnetic or magnetizable pigment particles using a magnetic field, the printing press may include a conveying device comprising a cylinder that generates a magnetic field and rotates with the substrate, or a flat plate that generates a magnetic field, on which the substrate is placed.

Banknote printing (including polymer banknote printing) is typically performed using an automated feeder printing press. To improve printing efficiency, a single sheet of paper contains multiple banknotes arranged along multiple rows and columns. At the end of the printing process, individual banknotes are obtained by cutting the paper between the columns and rows.

For security and anti-counterfeiting reasons, and to ensure users' trust in the currency and their ability to identify and distinguish banknotes from counterfeit ones without any doubt, it is crucial that all banknotes exhibit the exact same appearance, regardless of their position on the paper during the printing process. In other words, it is desirable that the first, last, or any banknote along the center line or row of a sheet of paper has the exact same final appearance as all other banknotes on the same sheet and all banknotes on other sheets of paper.

The goal of this invention is to improve the generation of N security files on the same substrate.

According to the first embodiment, a conveying device is provided for orienting sheet-like magnetic or magnetizable pigment particles contained in a radiation-curable coating composition and coated on a substrate. The conveying device is either a flat-plate conveying device or a cylindrical conveying device. The transmission device comprises: N identical magnetic blocks aligned along alignment lines disposed on the outer surface of the transmission device, each magnetic block including M magnetic field generating devices that generate corresponding magnetic fields, such that each magnetic block generates a block magnetic field, where N is greater than or equal to two and M is greater than or equal to one; and a shielding element disposed between every two adjacent magnetic blocks, the shielding element being made of a material that at least partially isolates the block magnetic field of each magnetic block from the block magnetic fields of other magnetic blocks.

Without shielding elements, adjacent magnetic field generating devices of the conveying device may generate overlapping magnetic fields when configured close to each other. This could lead to irregularities in the magnetic field that orients magnetic or magnetizable pigment particles along the substrate. Specifically, the first and Nth magnetic blocks (located on the edge of the flat conveying device or the "unfolded" cylindrical conveying device) each have only one adjacent magnetic block along the alignment line, while the second to (N-1)th magnetic blocks (located more centrally in the conveying device) have two adjacent magnetic blocks along the alignment line. Due to this difference in the number of adjacent magnetic blocks, the magnetic field that orients the magnetic or magnetizable pigment particles is not the same along the alignment line, resulting in undesirable differences in security features printed on different sections of the substrate (e.g., on different banknotes or other security documents).

Shielding elements allow this problem to be overcome and prevent adjacent magnetic blocks from interfering with each other. In this way, the same block magnetic field, oriented to the magnetic or magnetizable pigment particles, is applied along the alignment line to each security document formed on the substrate (a security document has pigment particles oriented by one magnetic block). Advantageously, identical security documents can be formed.

The conveying device can be part of a printing press and houses a magnetic block for orienting magnetic or magnetizable pigment particles. The conveying device can be cylindrical in shape and rotate about an axis to transport a substrate, or it can be flat in shape on which the substrate can be placed.

In contrast to needle-shaped pigment particles, which can be considered quasi-one-dimensional particles, plate-shaped pigment particles are quasi-two-dimensional particles due to their larger aspect ratio. Plate-shaped pigment particles can be viewed as two-dimensional structures, where dimensions X and Y are generally larger than dimension Z. In this technique, plate-shaped pigment particles may be referred to as flattened oval particles or flakes. Such pigment particles can be described as having a principal axis X corresponding to their longest dimension across the pigment particle and a second axis Y perpendicular to X and corresponding to the second longest dimension across the pigment particle. In other words, the XY plane is roughly defined by the plane formed by the first and second longest dimensions of the pigment particle, while the Z dimension is ignored.

The sheet-like magnetic or magnetizable pigment particles described herein exhibit anisotropic reflectivity to incident electromagnetic radiation due to their non-spherical shape, and the hardened/cured adhesive material is at least partially transparent to incident electromagnetic radiation. As used herein, the term "anisotropic reflectivity" means that the proportion of incident radiation from a first angle reflected by the particle to a specific (observational) direction (second angle) varies with the orientation of the particle; that is, a change in the particle's orientation relative to the first angle can result in different amounts of reflection to the observational direction.

Flaky magnetic or magnetizable pigment particles are dispersed in a coating layer comprising a hardened binder material that fixes the orientation of the flaky magnetic or magnetizable pigment particles. As used herein, the term "layer" refers to a coating layer that is at least partially cured, wherein the orientation of the flaky magnetic or magnetizable pigment particles is fixed/frozen (on the other hand, the term "composition" specifically refers to an ink). The binder material is at least in its hardened or solid state (also referred to herein as the second state) and is at least partially transparent to electromagnetic radiation in the wavelength range encompassed between 200 nm and 2500 nm (i.e., within the wavelength range commonly referred to as the "spectrum" and including the infrared, visible, and ultraviolet portions of the electromagnetic spectrum). Therefore, at certain wavelengths within this range, the particles contained in the adhesive material in its hardened or solid state and their orientation-related reflectivity can be perceived by the adhesive material. Preferably, the hardened adhesive material is at least partially transparent to electromagnetic radiation contained between 200 nm and 800 nm, more preferably between 400 nm and 700 nm. Herein, the term "transparent" means that the transmission of electromagnetic radiation through a 20 μm layer of hardened adhesive material present in the optical feature (excluding sheet-like magnetic or magnetizable pigment particles, but including all other optional components in the optical feature (where such components are present)) is at least 50% at the wavelength of interest, more preferably at least 60%, and even more preferably at least 70%. This can be determined, for example, by measuring the transmittance of a test specimen of a hardened adhesive material (excluding sheet-like magnetic or magnetizable pigment particles) according to a well-established test method (e.g., DIN 5036-3 (1979-11)).

The sheet-like magnetic or magnetizable pigment particles described herein are defined as having anisotropic reflectivity to incident electromagnetic radiation due to their non-spherical shape, and the cured adhesive material is at least partially transparent to incident electromagnetic radiation. As used herein, the term "anisotropic reflectivity" means that the proportion of incident radiation from a first angle reflected by the particle to a specific (observational) direction (second angle) varies with the orientation of the particle; that is, a change in the orientation of the particle relative to the first angle can result in different amounts of reflection to the observation direction. Preferably, the sheet-like magnetic or magnetizable pigment particles described herein have anisotropic reflectivity to incident electromagnetic radiation in certain portions or throughout the wavelength range of about 200 nm to about 2500 nm, more preferably about 400 nm to about 700 nm, such that a change in particle orientation results in a change in the amount of reflection of the particle in a certain direction. As will be known to those skilled in the art, the magnetic or magnetizable pigment particles described herein differ from conventional pigments in that conventional pigment particles exhibit the same color and reflectivity regardless of particle orientation, while the magnetic or magnetizable pigment particles described herein exhibit reflectivity or color, or both, depending on particle orientation.

The radiation-curable coating compositions and coatings described herein comprise the sheet-like magnetic or magnetizable pigment particles described herein, preferably in quantities of about 1 wt% and about 40 wt%, more preferably between about 3 wt% and about 35 wt%, and more preferably between about 5 wt% and about 30 wt%, the weight percentages being based on the total weight of the radiation-curable coating compositions or coatings.

Suitable examples of the sheet-like magnetic or magnetizable pigment particles described herein include, but are not limited to, pigment particles comprising: magnetic metals selected from the group consisting of cobalt (Co), iron (Fe), and nickel (Ni); magnetic alloys of iron, manganese, cobalt, nickel, or mixtures thereof; magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures thereof; or mixtures thereof. The term "magnetic" in relation to metals, alloys, and oxides refers to ferromagnetic or ferrimagnetic metals, alloys, and oxides. Magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures thereof may be pure oxides or mixed oxides. Examples of magnetic oxides include, but are not limited to _, iron oxides, such as _hematite ( _Fe₂O₃ ), magnetite ( _Fe₃O₄ ), chromium dioxide ( _CrO₂ ), magnetic ferrite ( _MFe₂O₄ ), magnetic spinel ( _MR₂O₄ ), magnetic _hexagonal ferrite ( _{MFe¹²O¹⁹} ), magnetic orthoferrite ( _RFeO₃ ), and magnetic garnet _M₃R₂ ( _AO₄ ) _₃ , where M represents a divalent metal, R represents _a trivalent metal, _{and A} represents a tetravalent metal.

Examples of sheet-like magnetic or magnetizable pigment particles described herein include, but are not limited to, pigment particles comprising a magnetic layer M made of one or more of the following: magnetic metals such as cobalt (Co), iron (Fe), or nickel (Ni); and magnetic alloys of iron, cobalt, or nickel, wherein such magnetic or magnetizable pigment particles may be multilayer structures comprising one or more additional layers. Preferably, one or more additional layers are: layer A, which is independently made of one or more of the group consisting of metallic fluorides (such as magnesium fluoride ( _MgF2 )), silicon oxide (SiO), silicon dioxide ( _SiO2 ), titanium oxide ( _TiO2 ), and aluminum _oxide ( _Al2O3 ) (more preferably silicon dioxide ( _SiO2 )); or layer B, which is independently made of one or more of the group consisting of metals and metal alloys, more preferably the group consisting of reflective metals and reflective metal alloys, and more preferably the group consisting of silver (Ag), aluminum (Al), chromium (Cr), and nickel (Ni) (and even more preferably aluminum (Al)); or one or more layers A (such as layer A as described above) and a combination of one or more layers B (such as layer B as described above). Typical examples of sheet-like magnetic or magnetizable pigment particles as multilayer structures as described above include, but are not limited to, A/M multilayer structures, A/M/A multilayer structures, A/M/B multilayer structures, A/B/M/A multilayer structures, A/B/M/B multilayer structures, A/B/M/B/A multilayer structures, B/M multilayer structures, B/M/B multilayer structures, M/A/M multilayer structures, etc. Layered structure, B/A/M/A multilayered structure, B/A/M/B multilayered structure, B/A/M/B/A/ multilayered structure, B/A/M/A/B multilayered structure, B/A/B/A/M/A/B/A/B multilayered structure, A/B/A/B/A/M/A/B/A/B/A multilayered structure, wherein layer A, magnetic layer M, and layer B are selected from the layers described above.

The curable coating composition may be an ultraviolet-visible radiant curable coating composition and may contain sheet-like optically variable magnetic or magnetizable pigment particles, and/or sheet-like magnetic or magnetizable pigment particles that do not have optically variable properties. Preferably, at least a portion of the sheet-like magnetic or magnetizable pigment particles described herein are composed of sheet-like optically variable magnetic or magnetizable pigment particles. In addition to the explicit security provided by the color-shifting properties of optically variable magnetic or magnetizable pigment particles (which allows for easy detection, identification, and/or differentiation of articles or security documents containing inks, coating compositions, or coatings containing the optically variable magnetic or magnetizable pigment particles described herein, and their potential counterfeits using unassisted human senses), the optical properties of optically variable magnetic or magnetizable pigment particles can also be used to act on machine-readable tools that identify optical features. Therefore, the optical properties of optically variable magnetic or magnetizable pigment particles can simultaneously serve as implicit or semi-implicit security features in the authentication process, where the optical (e.g., spectral) properties of the pigment particles are analyzed, thus increasing the ability to prevent counterfeiting.

The use of sheet-like, optically variable, magnetic, or magnetizable pigment particles in coatings to produce optical features enhances the importance of optical features as security features in security document applications, as such materials are reserved for the security document printing industry and are not available for public purchase.

As described above, preferably, at least a portion of the sheet-like magnetic or magnetizable pigment particles are composed of sheet-like optically variable magnetic or magnetizable pigment particles. More preferably, they are composed of sheet-like magnetic thin-film interference pigment particles or sheet-like interference coated pigment particles.

Magnetic thin-film interference pigment particles are known to those skilled in the art and are cited, for example, in US 4,838,648; WO 2002/073250 A2; EP 0 686 675 B1; WO 2003/000801 A2; US 6,838,166; WO 2007/131833 A1; EP 2 402 401 B1; WO 2019/103937 A1; EP 3 587 500 A1; EP 3 587 501 A1; EP 3 587 502 A1; EP 3 587503 A1; WO 2020/006286 A1; WO 2020/131700 A1; US 2021/0101402; US As disclosed in US 2021/038812; US 2022/0282094 and the documents referenced therein. Preferably, the magnetic thin film interference pigment particles comprise pigment particles having a five-layer Fabry-Perot multilayer structure and/or pigment particles having a six-layer Fabry-Perot multilayer structure and/or pigment particles having a seven-layer Fabry-Perot multilayer structure and/or pigment particles having a nine-layer Fabry-Perot multilayer structure and/or pigment particles having an eleven-layer Fabry-Perot multilayer structure and/or pigment particles having a multilayer structure combining one or more multilayer Fabry-Perot structures.

A preferred five-layer Fabry-Perot multilayer structure is composed of an absorber/dielectric/reflector/dielectric/absorber multilayer structure, wherein the reflector and/or absorber are also magnetic layers. Preferably, the reflector and/or absorber are: magnetic layers containing nickel, iron and/or cobalt; and/or magnetic alloys containing nickel, iron and/or cobalt; and/or magnetic oxides containing nickel (Ni), iron (Fe) and/or cobalt (Co).

Other superior five-layer Fabry-Perot multilayer structures consist of a dielectric/reflector/magnetic/reflector/dielectric multilayer structure.

The preferred six-layer Fabry-Perot multilayer structure consists of an absorber/dielectric/reflector/magnetic/dielectric/absorber multilayer structure.

Preferred seven-layer Fabry-Perot multilayer structures consist of absorber/dielectric/reflector/magnetic/reflector/dielectric/absorber multilayer structures, such as the multilayer structures disclosed in US 4,838,648.

A preferred nine-layer Fabry-Perot multilayer structure consists of a dielectric/absorbing/dielectric/reflector/magnetic/dielectric/absorbing/dielectric multilayer structure.

The preferred eleven-layer Fabry-Perot multilayer structure consists of an absorber/dielectric/absorber/dielectric/reflector/magnetic/reflector/dielectric/absorber/dielectric/absorber multilayer structure.

Preferably, the reflector layer described herein is independently composed of the group consisting of metals and metal alloys, more preferably of reflective metals and reflective metal alloys, even more preferably of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr)), nickel (Ni) and their alloys, and even more preferably of one or more of aluminum (Al), chromium (Cr), nickel (Ni) and their alloys (and even more preferably aluminum (Al)). Preferably, the dielectric layer is independently composed of the group consisting of metal fluorides (such as magnesium fluoride ( _MgF₂ ), aluminum fluoride ( _AlF₃ ), cerium fluoride ( _CeF₃ ), lanthanum fluoride ( _LaF₃ ), sodium aluminum fluoride (e.g., _Na₃AlF₆ ), _neodymium fluoride ( _NdF₃ ), tungsten fluoride ( _SmF₃ ), barium fluoride ( _BaF₂ ), calcium fluoride ( _CaF₂ ), and lithium fluoride (LiF)) and metal oxides (such as silicon oxide (SiO), silicon dioxide ( _SiO₂ ), titanium oxide ( _TiO₂ ), and aluminum oxide ( _Al₂O₃ )), more preferably magnesium fluoride ( _MgF₂ ) and silicon dioxide ( _SiO₂ ) _. (More preferably magnesium fluoride ( _MgF₂ )) One or more of the group consisting of magnesium fluoride. Preferably, the absorber layer is independently made of the group consisting of aluminum (Al), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), titanium (Ti), vanadium (V), iron (Fe), tin (Sn), tungsten (W), molybdenum (Mo), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), their metal oxides, their metal sulfides, their metal carbides and their metal alloys, more preferably the group consisting of chromium (Cr), nickel (Ni), their metal oxides and their metal alloys, and even more preferably the group consisting of chromium (Cr), nickel (Ni) and their metal alloys. Preferably, the magnetic layer comprises nickel (Ni), iron (Fe), and/or cobalt (Co); and/or a magnetic alloy comprising nickel (Ni), iron (Fe), and/or cobalt (Co); and/or a magnetic oxide comprising nickel (Ni), iron (Fe), and/or cobalt (Co). When the magnetic thin-film interference pigment particles comprising a seven-layer Fabry-Perot structure are preferred, particularly preferred, the magnetic thin-film interference pigment particles comprise a seven-layer Fabry-Perot absorber/dielectric/reflector/magnetic/reflector/dielectric/absorber multilayer structure composed of a Cr/ _MgF₂ /Al/M/Al/ _MgF₂ /Cr multilayer structure, wherein M is Ni, Fe, or Co.

The substrates described herein are preferably selected from the group consisting of paper or other fibrous materials, such as cellulose, paper-containing materials, glass, metals, ceramics, plastics and polymers, metallized plastics or polymers, at least partially devitrifying plastic or polymer composites, and mixtures or combinations thereof. Typical paper, paper-like or other fibrous materials are made of a variety of fibers, including but not limited to abaca, cotton, flax, wood pulp, and blends thereof. As is well known to those skilled in the art, cotton and cotton/flax blends are preferably used for banknotes, while wood pulp is commonly used for non-banknote security documents. Typical examples of plastics and polymers include: polyolefins, such as polyethylene (PE) and polypropylene (PP); polyamides; polyesters, such as polyethylene terephthalate (PET), poly(1,4-butylene terephthalate) (PBT), and polyethylene (2,6-naphthoate) (PEN); and polyvinyl chloride (PVC). Spunlace fibers, such as those marketed under the trademark Tyvek®, can also be used as substrates. Typical examples of metallized plastics or polymers include the plastic or polymer materials described above that have metals disposed continuously or discontinuously on their surfaces. Typical examples of metals include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), gold (Au), silver (Ag), alloys thereof, and combinations of two or more of the above metals. The metallization of the plastic or polymer materials described above can be accomplished by electrodeposition, high-vacuum coating, or sputtering processes. Devitrifying polymers are developed to mimic the appearance and certain properties of familiar paper-based substrates used for security documents and consist of a polymer transparent substrate, which is typically surface-treated with a devitrifying layer on one or both sides to form a devitrifying polymer-based substrate. Typical examples of composite materials include, but are not limited to, multilayer structures or laminates of paper and at least one plastic or polymeric material (such as those described above), as well as plastic and/or polymeric fibers incorporated into paper-like or fibrous materials (such as those described above). Of course, the substrate may contain other additives known to those skilled in the art, such as fillers, sizing agents, whitening agents, processing aids, reinforcing agents, or wet strength agents.

Alternatively, and more preferably, the curing or hardening of the coating composition involves a chemical reaction that cannot be reversed by a simple temperature increase (e.g., up to 80°C) that may occur during typical use of the safety document. The terms “curing” or “curable” refer to a process that includes a chemical reaction, crosslinking, or polymerization of at least one component of the coated coating composition to transform it into a polymeric material with a molecular weight greater than that of the starting material. Preferably, curing results in the formation of a stable three-dimensional polymer network. Such curing is typically initiated by applying an external stimulus to the coating composition after (i) the coating composition has been applied to a substrate surface, and (ii) after or simultaneously with the orientation of sheet-like magnetic or magnetizable pigment particles. Preferably, the coating composition is an ink or coating composition selected from the group consisting of radiation-curable compositions, heat-drying compositions, oxidative-drying compositions, and combinations thereof. Particularly preferred are coating compositions selected from the group consisting of radiation-curable compositions. Radiation curing, particularly ultraviolet-visible light curing, advantageously results in a momentary increase in viscosity of the coating composition after exposure to curing radiation, thereby preventing any further movement of pigment particles after the magnetic orientation step and thus preventing any information loss. Preferably, curing is carried out by radiation curing (including ultraviolet-visible light radiation curing) or by electron beam radiation curing, more preferably by ultraviolet-visible light radiation curing.

The numbers N and M can be natural numbers. N magnetic blocks are arranged in a repeating pattern to form a magnetic field generating device. The N magnetic blocks being identical specifically means that they generate the same block magnetic field. They may also be identical in terms of the magnetic field generating device, size, or similar aspects included in each block. N is an integer of at least two. The magnetic field generating device of a single magnetic block can be housed together by a housing, such that each magnetic block forms a physical unit. The N magnetic blocks are aligned along the outer surface of the conveying device, specifically meaning that the N magnetic blocks are arranged on the outer surface of the conveying device, for example, arranged in holes, each containing one magnetic block. The magnetic blocks can be disposed on the outer surface such that pigment particles placed on a substrate facing the outer surface of the conveying device can sense the block magnetic field. All N magnetic blocks are arranged equidistantly from each other. Specifically, N magnetic blocks are arranged adjacent to each other seamlessly along the alignment line. The magnetic blocks being arranged "along the alignment line" can mean that they are aligned parallel to the alignment line.

M is an integer of at least one. Each magnetic block includes at least one magnetic field generating device. Each magnetic field generating device may include a permanent magnet, an electromagnetic magnet, a solenoid, a current-carrying wire, a plastic ferrite magnet, a combination of a plastic ferrite magnet and a permanent magnet, a soft magnet, a combination of a magnetic field generating device that generates a time-dependent magnetic field and a soft magnet, and/or similar devices that generate magnetic fields. Preferably, the magnetic field generating device is implemented as a permanent magnet. Each magnetic block can be used to orient pigment particles to create a security feature in the form of an optical effect layer (OEL) after curing. As used herein, "optical effect layer (OEL)" refers to a coating or layer comprising oriented sheet-like magnetic or magnetizable pigment particles and an adhesive, wherein the sheet-like magnetic or magnetizable pigment particles are oriented by a magnetic field and wherein the oriented sheet-like magnetic or magnetizable pigment particles are fixed/frozen in their orientation and position to form a magnetically induced image. The term "security feature" is used to refer to an image or graphic element that can be used for forensic purposes. Security features can be explicit and/or implicit security elements. Each security feature may include M security elements created by curing a radiocurable coating composition comprising pigment particles oriented by M magnetic field generating devices. Each of the M safety elements has a patterned shape and displays a specific magnetic effect obtained by exposure to a magnetic field generating device contained in a block of magnetic field.

At least one shielding element is placed between every two adjacent magnetic blocks, typically between the first and second magnetic blocks, between the second and third magnetic blocks, ..., and between the (N-1)th and Nth magnetic blocks. In other words, (N-1) shielding elements can be provided. The shielding elements are preferably positioned on alignment lines. The shielding elements are, in particular, elements that redirect the magnetic field lines from the magnetic blocks (which are arranged between them) so that these magnetic field lines do not cross each other (this corresponds to completely isolating the block magnetic fields of two adjacent magnetic blocks from each other). In some cases, slight interactions between the block magnetic fields of adjacent magnetic blocks can be tolerated, which is why it is said that shielding elements at least partially isolate the block magnetic field of a magnetic block from the block magnetic fields of other magnetic blocks.

According to one embodiment, the first-state transmission device further includes N housings, each for housing a magnetic block, at least a section of the housings forming a shielding element.

The housing specifically includes or corresponds to a shielding element. The housing may include compartments for accommodating individual magnetic field generating devices. Each magnetic block is housed by one housing. The housing may include a cover parallel to its outer surface, which is disposed between the substrate and the magnetic block during use of the conveying device. The section (part/portion) of the housing forming the shielding element may be a section of the housing located between two adjacent magnetic blocks.

According to another embodiment of the first state, the material of the shielding element is a material having a relative permeability greater than 40; and/or steel, especially S235 steel.

Preferably, the shielding element is made of a ferromagnetic metal. The relative permeability of a particular medium is defined as the ratio of the permeability of the particular medium to the permeability of free space (vacuum) (see Magnetic materials, Fundamentals and Applications, ^2nd Ed., Nicola A. Spaldin, pp. 16-17, Cambridge University Press, 2011). Here, "permeability" refers to magnetic permeability. Absolute permeability is specifically based on the change in flux density ΔB relative to the change in magnetic field strength ΔH. Relative permeability represents the magnetic performance of a given material. For example, a relative permeability of 100 means that the material's permeability is 100 times that of vacuum (by definition, relative permeability is 1, while the permeability of vacuum is 4π·10^(-7) H/m).

Here, "Steel S235" specifically refers to steel S235 as defined in the April 2005 standard DIN EN 10025-2.

According to another embodiment of the first state, the conveying device is a cylindrical conveying device, and the alignment line is: the outer circumference of the cross section of the cylindrical conveying device (preferred embodiment); or a side line on the outer surface of the cylindrical conveying device, which is parallel to the axis of the cylindrical conveying device.

Cylindrical conveying devices are characterized by a circular base. In the case of a cylindrical conveying device, the alignment line can be: the outer circumference of the cross-section of the cylindrical conveying device, which, if the cylindrical conveying device has a circular base, then has a circular shape; or a side line of the outer surface, parallel to the axis of rotation of the cylindrical conveying device, which is the axis of rotation of the cylinder passing through its center. The side line represents the height of the cylinder. The alignment line is the line along which N magnetic blocks are aligned. In particular, the alignment line is the line along which N magnetic blocks are close enough to each other to have overlapping magnetic fields (i.e., to influence each other). Therefore, shielding elements and/or compensating elements as described herein may become advantageous when the magnetic field influence of adjacent magnetic blocks is considered not small enough in the context of the intended application.

According to another embodiment of the first state, the conveying device is a rectangular flat plate conveying device, and the alignment line is parallel to one side of the rectangular flat plate conveying device.

In other words, the alignment line is parallel to the width or length of the transmission device.

In some embodiments, the magnetic blocks are arranged in an array on the transmission device, which means that some additional N magnetic blocks are arranged along a second alignment line (along the third, fourth, etc., respectively) parallel to the aforementioned (first) alignment line. This allows more security files to be generated simultaneously using a single substrate.

According to a second embodiment, a conveying device is provided for orienting sheet-like magnetic or magnetizable pigment particles contained in a coating composition and coated on a substrate to generate N security documents on the substrate. The conveying device is either a flat-plate conveying device or a cylindrical conveying device. The conveying device comprises: N identical magnetic blocks aligned along alignment lines disposed on the outer surface of the conveying device; each magnetic block includes M magnetic field generating devices, each generating a corresponding magnetic field such that each magnetic block generates a block magnetic field, where N is greater than or equal to two, and M is greater than or equal to one; and a compensating magnetic block, which, along the alignment lines, generates N identical magnetic fields. A guideline is positioned next to the first magnetic block, such that the first of the N magnetic blocks is positioned between the compensating magnetic block and the second of the N magnetic blocks. The compensating magnetic block includes at least one compensating magnetic field generating device, and the magnetic field provided by the at least one compensating magnetic field generating device is the same as the magnetic field of at least a portion of the magnetic field of one of the magnetic blocks, which includes the Mth magnetic field generating device.

The second-state transmission device is largely the same as the first-state transmission device. The components in the second-state transmission device that share the same names as those in the first-state transmission device will not be described again to avoid repetition. The difference between the first and second-state transmission devices is that the second-state transmission device includes a compensating magnetic block instead of a shielding element.

Compensating magnetic blocks are placed along the alignment line before the first magnetic block to simulate additional magnetic blocks. Therefore, the first to (N-1)th magnetic blocks of the N magnetic blocks each have two adjacent magnetic blocks along the alignment line, which means that the block magnetic field of each of these blocks is equally disturbed by the adjacent blocks, thereby achieving constant exposure to the magnetic field for the first to (N-1)th security documents formed on the substrate along the alignment line.

The first and second embodiments of the conveying apparatus offer different solutions to the same problem of reducing the irregularity of the magnetic field that orients magnetic or magnetizable pigment particles on different security documents of the substrate. The method for solving this same problem is to provide a shielding element in the first embodiment of the conveying apparatus and a compensating magnetic block in the second embodiment. While the shielding element allows for the prevention of interference between the block magnetic fields of adjacent magnetic blocks, the compensating magnetic block does not perform any shielding function; instead, it adds additional magnetic blocks to the N magnetic blocks, making the interference between adjacent magnetic blocks equal.

The compensating magnetic block can be aligned with other magnetic blocks along the alignment line. The compensating magnetic block can be the same magnetic block as the N magnetic blocks. Alternatively, the magnetic field provided by the compensating magnetic field generating device is the same as the magnetic field of at least a portion of the magnetic field of one of the magnetic blocks, which includes the Mth magnetic field generating device. Therefore, the compensating magnetic block can be a magnetic block that includes at least the Mth magnetic field generating device, thereby reproducing the magnetic field effect of the magnetic block placed before any of the N magnetic blocks except the first one. In addition to the Mth magnetic field generating device, the compensating magnetic block may further include the (M-1)th magnetic field generating device, and so on, until it includes the first magnetic field generating device or all magnetic field generating devices except the first magnetic field generating device. The magnetic field generating devices of the compensating magnetic block are specifically arranged in the same manner (at the same location) as in the N magnetic blocks. The distance between the compensating magnetic block and the first magnetic block is specifically equal to the distance between two adjacent magnetic blocks in the N magnetic blocks. The compensating magnetic field generating device may also be different from the magnetic field generating devices of the magnetic blocks, but the magnetic field it provides is the same as the magnetic field of one or more of the magnetic field generating devices of the magnetic blocks.

Although N magnetic blocks are used in the process of creating N security files to orient the sheet-like magnetic or magnetizable pigment particles respectively, the compensating magnetic block is an additional block that specifically does not correspond to one of the N security files. In other words, each magnetic block except the compensating magnetic block is associated with one security file. The compensating magnetic block adjusts the magnetic field of the first adjacent magnetic block to orient the sheet-like magnetic or magnetizable pigment particles of the first security file accordingly.

According to one embodiment, the second-state transmission device further includes an additional compensating magnetic block disposed next to the Nth magnetic block along an alignment line, such that the Nth magnetic block is positioned between the additional compensating magnetic block and the (N-1)th magnetic block. The additional compensating magnetic block includes at least one additional compensating magnetic field generating device, and the magnetic field provided by the at least one additional compensating magnetic field generating device is the same as the magnetic field of at least a portion of the magnetic field of one of the magnetic blocks, wherein the magnetic block includes the first of M magnetic field generating devices.

An additional compensating magnetic block is disposed at the other end of the alignment line (after the Nth magnetic block) and has the same properties and serves the same purpose as the aforementioned compensating magnetic block. That is, the additional compensating magnetic block is placed after and aligned with the Nth magnetic block along the alignment line to simulate the additional magnetic block. Therefore, each of the first to Nth magnetic blocks among the N magnetic blocks has two adjacent magnetic blocks along the alignment line, which means that the block magnetic field of each of these magnetic blocks is equally disturbed by the adjacent magnetic blocks, thereby achieving constant exposure of the magnetic field for the first to Nth security documents formed on the substrate along the alignment line.

The additional compensating magnetic block can be the same magnetic block as the N magnetic blocks. Alternatively, the magnetic field provided by the additional compensating magnetic field generating device is the same as the magnetic field of at least a portion of one of the magnetic blocks, which includes the first magnetic field generating device. Therefore, the additional compensating magnetic block can be a magnetic block that includes at least the first magnetic field generating device, thereby reproducing the magnetic field effect of any magnetic block other than the Nth magnetic block placed in the Nth magnetic block, or the magnetic blocks following all magnetic field generating devices except the first magnetic field generating device. In addition to the first magnetic field generating device, the additional compensating magnetic block can further include a second magnetic field generating device, and so on, up to including the Mth magnetic field generating device. The magnetic field generating device for the additional compensation magnetic block is specifically configured in the same manner (at the same location) as the N magnetic blocks. The distance between the additional compensation magnetic block and the Nth magnetic block is specifically equal to the distance between two adjacent magnetic blocks among the N magnetic blocks. The additional compensation magnetic field generating device may also differ from the magnetic field generating device for the magnetic blocks, but the magnetic field it provides is the same as the magnetic field of one or more of the magnetic field generating devices for the magnetic blocks.

Although N magnetic blocks are used in the process of creating N security files to orient the sheet-like magnetic or magnetizable pigment particles respectively, the compensating magnetic block and the additional compensating magnetic block are additional blocks, specifically not corresponding to one of the N security files. In other words, each magnetic block except for the compensating magnetic block and the additional compensating magnetic block is associated with one security file. The additional compensating magnetic block adjusts the magnetic field of the adjacent Nth magnetic block to correspondingly orient the sheet-like magnetic or magnetizable pigment particles of the Nth security file.

The second-state transmission device may further include N housings, each for housing a magnetic block. Preferably, in the second state, the N housings do not include the shielding elements described above.

According to another embodiment of the second state, the magnetic field provided by at least one of the compensating magnetic field generating devices included in the compensating magnetic block is the same as the magnetic field of the Mth magnetic field generating device, and/or the magnetic field provided by at least one of the additional compensating magnetic field generating devices included in the additional compensating magnetic block is the same as the magnetic field of the first magnetic field generating device.

According to another embodiment, the second-state transmission device further includes: a shielding element disposed between every two adjacent magnetic blocks and between the compensating magnetic block and the first magnetic block among the N magnetic blocks, the shielding element being made of a material that at least partially isolates the block magnetic field of each magnetic block from the magnetic fields of the other magnetic blocks and from the magnetic field of the compensating magnetic block.

In the case where an additional compensating magnetic block is provided, the shielding element is further disposed between the additional compensating magnetic block and the Nth magnetic block. In this case, the shielding element is made of a material that at least partially isolates the block magnetic field of each magnetic block from the magnetic fields of other magnetic blocks, the magnetic field of the compensating magnetic block, and the magnetic field of the additional compensating magnetic block.

The shielding element may be the same as the shielding element described for the conveying device of the first state sample. The features described for the conveying device of the first state sample are also applicable in the context of this embodiment. This embodiment relates to a combination of conveying devices according to the first and second states samples. The advantage of combining the shielding element solution with the compensating magnetic block solution is that it can better ensure that the pigment particles of all security documents on the same substrate are oriented in the same way, thereby resulting in identical visual features on all security documents.

According to another embodiment of the first or second state of the transmission device, each magnetic block includes at least two different magnetic field generating devices.

This corresponds to M≥2, where the two magnetic field generating devices produce different magnetic fields, thereby producing different magnetic effects on the security document. These magnetic effects specifically include dynamic effects that provide motion illusions (such as those described below) and 3D effects that provide embossed illusions (such as those described below). In other embodiments, each magnetic block includes at least two identical magnetic field generating devices.

For example, an engraved magnetic plate containing one or more engravings, each engraved with a marked shape, can be used. As used herein, the term "mark" should mean a continuous or discontinuous layer consisting of a prominent mark, symbol, or pattern. Preferably, the one or more marks are selected from codes, symbols, alphanumeric characters, patterns, geometric patterns (e.g., circles, triangles, and regular or irregular polygons), letters, words, numbers, emblems, graphics, portraits, and combinations thereof. Examples of codes include encoded symbols, such as encoded alphanumeric data, one-dimensional barcodes, two-dimensional barcodes, QR codes, data matrices, and infrared readout codes. When an OEL containing one or more marks is tilted, the security feature can exhibit dynamic movement. For example, a magnetic field generating device includes at least a bar dipole magnet and an engraved magnetic plate, the engraved magnetic plate including one or more engravings, the one or more engravings having a marked shape.

The aforementioned effect may include dynamic movements such as: bright reflective stripes moving in one direction when the substrate is tilted around an axis, as described in, for example, US 2005/0106367, WO 2020/160993 A1, and WO 2014/198905 A2. The effect may also include dynamic movements such as: patterns in bright and dark areas moving when the substrate is tilted, as described in, for example, WO 2013/167425 A1, WO 2021/083808 A1, and WO 2021/083809 A1. The effect may also include dynamic movements such as: toroidal bodies moving when the substrate is tilted, as described in, for example, WO 2014/108404 A2 and WO 2014/108303 A2. The effect may also include dynamic movements in which the toroidal body has a size that changes when the substrate is tilted, as described in WO 2017/064052 A1, WO 2017/080698 A1 and WO 2017/148789 A1. The effect may also include dynamic movements in which one or more toroidal bodies have shapes that change when the substrate is tilted, as described in WO 2018/054819 A1. The effect may also include dynamic movements in which a crescent shape moves and rotates when the substrate is tilted, as described in WO 2019/215148 A1. The effect may also include dynamic motions such as: the rings surrounded by one or more rings having shapes and/or brightness that change when the substrate is tilted, for example, as described in WO 2020/193009 A1. The effect may also include dynamic motions such as: at least one comet-shaped spot rotating around the center of rotation when the substrate is tilted, for example, as described in WO 2019/038371 A1, WO 2019/038370 A1 and WO 2019/038369 A1.

According to the third state sample, a magnetic orientation unit is provided for a conveying device of the first state sample, the second state sample, or any embodiment of the first or second state sample. The magnetic orientation unit is used to orient sheet-like magnetic or magnetizable pigment particles contained in a radiation-curable coating composition and coated on a substrate. The magnetic orientation unit comprises: a magnetic block, the magnetic block including M magnetic field generating devices, each of the magnetic field generating devices generating a corresponding magnetic field, such that the magnetic block generates a block magnetic field, wherein M is greater than or equal to one; and a shielding element and/or a compensating magnetic block; wherein the shielding element is disposed next to the magnetic block, the shielding element being made of a material that at least partially blocks the block magnetic field; and/or a compensating magnetic block disposed next to the magnetic block, the compensating magnetic block including at least one compensating magnetic field generating device, the magnetic field provided by the at least one compensating magnetic field generating device being the same as the magnetic field of at least a portion of the magnetic field of one of the magnetic blocks, the one magnetic block including the Mth magnetic field generating device.

The magnetic orientation unit according to the third state corresponds to a sub-part of the conveying device of the first or second state, the sub-part comprising only one magnetic block and a shielding element and/or a compensating magnetic block. Alternatively, the magnetic orientation unit may also include additional compensating blocks as defined above. Elements with the same names as those previously described in the first or second state are identical and therefore will not be described again. The advantages are the same as those described for the first and second states. All features described for the first or second state (or any embodiment thereof) also apply to the magnetic orientation unit according to the third state.

According to the fourth specification, a printing press is provided, which includes a conveying device according to the first or second specification (or any embodiment thereof).

This printing press is used to print security features on security documents on a substrate in the form of an optical effect layer (OEL). In addition to the conveying device, the printing press specifically includes components for coating pigment particles onto the substrate, conveying the substrate, curing the coating composition including the pigment particles, and/or optionally dividing the substrate. All features described for the first or second sample (or any embodiment thereof) are also applicable to the printing press according to the fourth sample.

According to the fifth state, a method is provided for generating at least N security documents, each of which contains a security feature, the security feature containing at least M security elements (each specifically forming an OEL), where N is equal to or greater than two, and M is greater than or equal to one. The method comprises: a) providing a substrate, preferably in the form of paper; b) coating the surface of the substrate with a radiation-curable coating composition comprising sheet-like magnetic or magnetizable pigment particles, the coating composition being in a first state, the coating composition being coated with M independent and optionally spaced patterned designs for each of N security features; c) exposing the magnetic or magnetizable pigment particles to the magnetic field of a conveying device according to a first state, a second state, or any embodiment of the first or second state, so as to orient at least a portion of the sheet-like magnetic or magnetizable pigment particles of each of the M coated patterned designs of a security feature according to the bulk magnetic field of the magnetic block of the conveying device; and d) Preferably, the coating composition of step b) is cured to a second state simultaneously with step c) to fix the sheet-like magnetic or magnetizable pigment particles in their adopted positions and orientations, so that each cured pattern forms one of the safety elements.

Elements having the same name as those previously described in the first or second aspect are identical and therefore will not be described again. All features described for the first or second aspect (or any embodiment thereof) also apply to the method according to the fifth aspect. The described method allows the generation of at least N security files, specifically N security files. These are generated on the same substrate and can then be divided (specifically using separate machines) to obtain individual security files. At least N security files can be generated simultaneously.

The coating step b) described herein is preferably performed by a printing process, preferably a combination of freehand screen printing, rotary gravure printing, flexographic printing, and gravure printing (also known in this technique as engraved copperplate printing and engraved stencil printing), more preferably a combination of freehand screen printing, rotary gravure printing, and flexographic printing. These processes are well known to those skilled in the art and are described, for example, in Printing Technology, J. M. Adams and P. A. Dolin, Delmar Thomson Learning, 5th Edition.

Furthermore, after applying the coating composition described herein (step b) to the surface of the substrate described herein, and simultaneously with or concurrently with thereon, the plate-like magnetic or magnetizable pigment particles are oriented by applying a magnetic field to align them along magnetic field lines (step c). Following or simultaneously with step c, which involves orienting/aligning the plate-like magnetic or magnetizable pigment particles by applying a magnetic field, the orientation of the plate-like magnetic or magnetizable pigment particles is fixed or frozen, i.e., by curing the coating composition (step d). The coating composition must therefore noteworthyly possess: a first state, i.e., a liquid or paste state, in which the coating composition is sufficiently wet or soft such that the sheet-like magnetic or magnetizable pigment particles dispersed in the coating composition can move, rotate, and/or orient themselves freely when exposed to a magnetic field; and a second hardened (e.g., solid) state, in which the sheet-like magnetic or magnetizable pigment particles are fixed or frozen in their respective positions and orientations.

These first and second states are preferably provided by using a certain type of coating composition. For example, the components of the coating composition, other than the lamellar magnetic or magnetizable pigment particles, can be in the form of inks or coating compositions, such as those used in security applications (e.g., for banknote printing). The aforementioned first and second states can be provided by using materials that exhibit an increase in viscosity in response to stimuli (such as temperature changes or exposure to electromagnetic radiation). That is, when the fluid binder material hardens, solidifies, or solidifies, the binder material transforms into the second state, i.e., a hardened, solidified, or solid state, in which the lamellar magnetic or magnetizable pigment particles are fixed in their current position and orientation and can no longer move or rotate within the binder material.

In step b), a coating composition comprising pigment particles is applied, particularly to the substrate locations where the substrate will align with the magnetic field generating device of the conveying device when it faces the conveying device in step c). In step b), the coating composition can be printed to form patterned designs at those predetermined locations. As described above, the conveying device comprises N magnetic blocks, each having M magnetic field generating devices. The coating composition is applied to the substrate to form M independent and optionally spaced (i.e., non-contacting) patterned designs for each of the N security features (corresponding to a total of N x M patterned designs). These patterned designs may be applied along a line. Each coated pattern can be oriented towards a magnetic field generating device in step c). Therefore, each magnetic field orients the pigment particles of the M coated patterns for the same security feature. The M coated patterns of the security feature can have the same shape or different shapes. Preferably, all N security features are identical, meaning that each of the N security features includes the same M pattern patterns and the same magnetic effect, i.e., each of the N security features includes the same M security elements (in terms of shape and magnetic orientation).

M independent patterned designs may be in contact with each other (i.e., not spaced apart) to increase anti-counterfeiting capabilities. The term "independent" here refers to the fact that the M patterned designs are different patterns and/or different magnetic effects applied to them, creating different security elements within the security feature. The independent patterned designs can form visually separate and distinguishable security elements within the security feature.

As defined herein, a secure document (such as a banknote) includes a security feature. A security feature consists of multiple security elements characterized by (i) their shape (pattern) and (ii) the magnetic effect applied to them by a corresponding magnetic field generating device. In a non-cured state, a coating composition comprising pigment particles is coated onto a substrate in the form of a pattern. Each of the M cured pattern (i.e., each of the M OELs) forms a security element, and the M security elements (M OELs) form the security feature present in each of the N secure documents.

According to one embodiment, the fifth-state method further includes the following steps: e) dividing the substrate among N security features to obtain individual and identical security documents.

As a result of segmentation among N security features, N individual and identical security documents are obtained. Each security document (such as a banknote) may include one security feature, each of which specifically includes a multiplicity of M security elements. The security features may have an elongated shape and extend, for example, along the entire width of the security document (especially the banknote). Typical examples of such elongated security features referenced in this technique are security threads, security strips, and security foils. The fifth-state method can be extended to create an array of N x P security documents, each of which includes one security feature. In this case, a transmission device with N x P magnetic blocks provides not just one but P alignments of the N security features on the substrate. Therefore, a large number of identical security documents can be generated using a single substrate. Segmentation can be interpreted as cutting.

According to the fifth-state implementation, each of the N security features includes at least two different security elements.

Each security feature includes at least two distinct security elements, which in particular means that the security elements have different patterns (shapes) and/or different magnetic effects associated with them, and are at least partially adjacent to each other on a security document.

According to one embodiment, the fifth-state method further includes: between step b) and step c), exposing the sheet-like magnetic or magnetizable pigment particles to a time-correlated magnetic field to pre-orient the sheet-like magnetic or magnetizable pigment particles in a biaxial manner.

The orientation of sheet-like magnetic or magnetizable pigment particles in an adhesive material is achieved through two orientation steps, which are performed by: i) biaxial orientation of the sheet-like magnetic or magnetizable pigment particles according to an external time-correlated magnetic field generated by a first magnetic field generating device (the time-correlated magnetic field is static or constant, and the substrate is subjected to the time-correlated magnetic field by moving the substrate in front of the magnetic field generating device that generates the static or constant magnetic field); and subsequently ii) uniaxial reorientation of the sheet-like magnetic or magnetizable pigment particles according to a static external magnetic field generated by a second magnetic field generating device, which corresponds to the conveying device described herein. For example, such two-step orientation of pigment particles is described in EP 3079836 A1.

Biaxial orientation means orienting plate-like magnetic or magnetizable pigment particles in a manner that restricts their two principal axes. That is, each plate-like magnetic or magnetizable pigment particle can be considered to have a major axis in the plane of the pigment particle and an orthogonal minor axis in the plane of the pigment particle. The major and minor axes of the plate-like magnetic or magnetizable pigment particles are each oriented according to a time-dependent magnetic field. In practice, this results in adjacent plate-like magnetic pigment particles that are close to each other in space being substantially parallel to each other. To perform biaxial orientation, the plate-like magnetic pigment particles must be subjected to a strongly time-dependent external magnetic field.

Examples of such first magnetic field generating devices for biaxially oriented pigment particles include, but are not limited to, the devices disclosed in EP 2 157 141 A1, Z.Q. Zhu and D. Howe (Halbach permanent magnet machines and applications: a review, IEE. Proc. Electric Power Appl., 2001, 148, p. 299-308), US 2007/0172261 A1, CN 102529326 B, WO 2015/082344 A1, WO 2016/026896 A1, WO2018/141547 A1, and WO 2021/239607 A1.

Alternatively, the pigment particles can be oriented by exposing the curable coating composition to the magnetic field resulting from the combination of the first magnetic field generating device for biaxially oriented pigment particles and a soft magnetic plate comprising one or more recesses and/or one or more voids and/or one or more protrusions, as described in WO 2019/14142 A1, WO 2019/141453 A1 and WO 2015/086257 A1.

The invention will be described more fully below with reference to the accompanying figures, in which the same numbers throughout the different figures represent the same elements, and in which the distinctive features and characteristics of the invention are shown.

The magnetic assemblies and methods described herein are now described in more detail with reference to the accompanying drawings and specific embodiments for generating an optical effect layer (OEL) as a security feature on a substrate (particularly on a polymer substrate, preferably on a non-devitrifying region of a security foil that mimics a devitrifying layer on a polymer substrate). These features include security lines, security strips, or security foils.

Figure 1 schematically illustrates a sheet of paper S forming a substrate for printing banknotes 1, particularly polymer banknotes 1. The sheet of paper S comprises multiple banknotes 1 arranged edge-to-edge along multiple rows (six rows Y1-Y6 in the example of Figure 1) and multiple columns (eight columns R1-R8 in the example of Figure 1). At the end of the printing process, individual banknotes 1 are obtained by cutting (dividing) the sheet of paper S along the dotted lines shown in Figure 1 between columns R1-R8 and between rows Y1-Y6. For example, the sheet of paper S shown in Figure 1 will produce 48 individual banknotes 1. In Figure 1, in the case of polymer banknote paper S, the gray area 2 schematically represents the deoptery area, while the white stripe 3 schematically represents the non-deoptery transparent area that mimics the security foil.

As shown in Figure 1, the paper S includes the leading edge FE and trailing edge BE of the banknote 1, allowing it to be conveyed through the printing press using conveying components (clamps, rollers, brushes, etc.) during various printing processes. The non-opaque area 3 of each of the banknotes 1 has three security elements A-C. In an alternative embodiment, the security elements A-C may be located on opaque areas, such as opaque area 2 of the banknote 1.

Figures 2a and 2b schematically illustrate examples of banknotes 1 on substrate S of Figure 1. These banknotes include an opaque coating (gray area 2) and a non-opaque area (transparent area 3). The non-opaque area represents a security foil and has security elements A-C in the shape of patterned designs F1-F3 (e.g., sailboat F1, flower F2, and pine tree F3 in Figure 2a). These security elements A-C contain magnetic or magnetizable pigment particles oriented according to magnetic effects G1-G3. Different magnetic effects G1-G3 provide different visible light effects (represented by gray lines or gray rings). Figure 2a shows an example of a banknote with three patterned designs F1, F2, and F3 forming security elements A and B, and two magnetic effects G1 and G2. Figure 2b illustrates an example of a banknote with three patterned designs F1, F2, and F3 forming security elements A, B, and C, and three magnetic effects G1, G2, and G3. The banknote 1 may be designed differently from the example shown in Figure 2. For example, each banknote 1 may include one, two, or more designs F1-F3, which may have pigment particles oriented according to at least one, but preferably multiple, different magnetic effects G1-G3. Security elements A-B-A and A-B-C form elongated security features 4.

Figure 3 illustrates a conveying device 100 used to orient pigment particles on a substrate S to obtain a desired effect. Figure 3 shows the outer surface of the conveying device 100. The conveying device 100 here is a cylindrical conveying device 100. The side surfaces forming the outer surface of the cylindrical conveying device 100 have a rectangular shape when unfolded, corresponding to the representation in Figure 3. The conveying device 100 has a structure similar to that of the substrate S in Figure 1, because the conveying device 100 is used to orient the pigment particles on the substrate S when the substrate S is placed in front of the conveying device 100. Therefore, the conveying device 100 has N×P magnetic blocks 102 (for ease of reading, only some magnetic blocks 102 with reference numerals are shown in Figure 3), where N is the number of columns and N=8, and P is the number of rows and P=6. N=8 identical magnetic blocks 102 are arranged along each alignment line 103 (aligned and parallel to the alignment line), which in the representation of Figure 3 extends through a row but follows the outer circumference of the cross section of the cylindrical conveying device 100. Each magnetic block 102 has M=3 magnetic field generating devices 101 for generating magnetic fields according to magnetic effects G1-G3. In the example of Figure 3, the magnetic blocks 102 in the leftmost three rows each include magnetic field generating devices 101 that generate magnetic effects G1-G2-G1 (i.e., the banknotes in Figure 2a) in this order, while the magnetic blocks 102 in the rightmost three rows each include magnetic field generating devices 101 that generate magnetic effects G1-G2-G3 (i.e., the banknotes in Figure 2b) in this order.

As can be seen in Figure 3, the upper and lower magnetic blocks 102 (i.e., the magnetic blocks 102 adjacent to the rear edge BE and front edge FE of the paper S) form an edge magnetic block 104. This edge magnetic block has only one neighbor along its alignment line 103, while all other magnetic blocks 102 have two perpendicular neighbors. Since adjacent magnetic blocks 102 along the alignment line 103 affect each other's magnetic fields, a magnetic block 102 with one neighbor (i.e., magnetic block 104) exposes the pigment particles to a different magnetic field than a magnetic block 102 with two neighbors. Therefore, not all banknotes 1 are exposed to the same magnetic field, resulting in variations in the effects produced on the banknotes 1. Such variations are undesirable; therefore, the transmission device 100 includes components to prevent variations in the effects produced by different magnetic blocks 102 on the banknote 1. These components may take different forms as described below. First Embodiment

According to a first embodiment of the transmission device 100, the aforementioned problem is solved by providing shielding elements 105 along the alignment line 103 between adjacent magnetic blocks 102. This is shown in Figure 4, which shows an example of a row of the transmission device 100 of Figure 3, wherein shielding elements 105 are provided along the alignment line 103 between each adjacent magnetic block 102. In the example of Figure 4, seven shielding elements 105 are provided. More generally, (N-1) shielding elements 105 are provided to align N magnetic blocks 102 along the alignment line 103. The shielding elements 105 are made of S235 steel. The shielding elements 105 isolate the magnetic field of each magnetic block 102 from the magnetic fields of adjacent magnetic blocks 102. This means that the magnetic fields from adjacent magnetic blocks 102 do not interact with each other. Therefore, whether a magnetic block 102 has a single neighbor along the alignment line 103 (as in the case of the edge magnetic block 104) or two neighbors, the block magnetic field provided by each magnetic block 102 to the substrate S is the same. This results in the same effect on all banknotes 1 on the substrate S.

The shielding element 105 may be part of a housing 301, each housing a magnetic block 102. This housing 301 is shown in Figure 5, which illustrates a magnetic orientation unit 300 comprising the housing 301 for housing a magnetic block 102. Here, the shielding element 105 is formed from the sidewall of the housing 301. The housing 301 houses three magnetic field generating devices 101 forming a magnetic block 102. The housing 301 includes a cover 302. Figure 5a shows a cross-sectional view of the magnetic assembly 300, and Figure 5b shows a top view of the magnetic assembly 300 (in Figure 5b, the cover 302 is not shown for clarity). Figure 5c schematically shows a cross-sectional view accommodating only the shell 301. Second Embodiment

According to a second embodiment of the transmission device 100, the above-mentioned problem is solved by providing the transmission device 100 with compensating magnetic blocks 106 and optional additional compensating magnetic blocks 107, which are shown in Figure 6. Figure 6 shows a row of N=8 magnetic blocks 102 of the transmission device 100 in Figure 3, which are aligned along the alignment line 103. Compared with the magnetic blocks 102, the compensating magnetic blocks 106 and additional compensating magnetic blocks 107 are not used to create corresponding effects on the substrate S, but are only used to simulate additional adjacent magnetic blocks 102 for the edge magnetic blocks 104.

The compensating magnetic block 106 faces the leading edge FE of the paper S when it is placed on the conveying device 100 and aligned with the alignment line 103. The compensating magnetic block 106 includes a compensating magnetic field generating device 108, which is the magnetic field generating device 101 that generates the magnetic effect G3 and thus corresponds to the third (Mth) magnetic field generating device 101 of each aligned magnetic block 102 in Figure 6. Similarly, the additional compensating magnetic block 107 faces the trailing edge BE of the paper S when it is placed on the conveying device 100 and aligned with the alignment line 103. The additional compensating magnetic block 107 includes an additional compensating magnetic field generating device 109, which is the magnetic field generating device 101 that generates the magnetic effect G1 and thus corresponds to the first magnetic field generating device 101 of each aligned magnetic block 102 in Figure 6. Therefore, the compensating magnetic block 106 and the additional compensating magnetic block 107 simulate the magnetic field of the adjacent magnetic block 102 for the edge magnetic block 104. Therefore, the magnetic field generated on the substrate S by each magnetic block 102 is the same, resulting in the same security feature 4 on each banknote 1.

The compensating magnetic block 106 and/or the additional compensating magnetic block 107 may include multiple magnetic field generating devices 101, rather than just one compensating magnetic field generating device 108 or 109, and in particular, as many as the other magnetic blocks 102, so that the compensating magnetic block 106 and/or the additional compensating magnetic block 107 can be the same as the magnetic block 102.

Each magnetic block 102, compensating magnetic block 106, and/or additional compensating magnetic block 107 can be accommodated by a housing 301 as described in Figure 5. The housing 301 may include a shielding element 105, or may be provided without a shielding element 105. Method for generating security documents.

The transmission device 100 of the first or second embodiment described above can be used in a process that generates at least N secure documents (here, banknote 1). This process is illustrated in Figures 7 and 8, and will be described in detail below.

In step a) of Figure 7, a paper-like substrate S is provided. In step b), a radiation-curable coating composition 200 containing sheet-like magnetic or magnetizable pigment particles is applied to the surface of the substrate S. The coating composition 200 is applied in a first state, in which the pigment particles can move on the surface of the substrate S. The coating composition 200 is here applied by screen printing for each of the N security features in the form of M independent and optionally spaced patterns. In other words, one pattern is printed for each security element A-C of the banknote 1 to be created. The patterns are printed in the shapes of patterns F1-F3 shown in Figure 2.

In optional step f), pigment particles are exposed to a time-dependent magnetic field generated by the magnetic field generating device 201 for generating a time-dependent magnetic field, in order to pre-orient the pigment particles in a biaxial manner. The substrate S is moved in front of the magnetic field generating device 201 for generating a time-dependent magnetic field, as indicated by the right-pointing arrow in step f) of Figure 7. The substrate S is then placed on the conveying device 100.

In subsequent step c), pigment particles are exposed to a block magnetic field generated by the magnetic block 102 of the conveying device 100. For this purpose, the substrate S is positioned facing the conveying device 100, such that each pattern F1-F3 coated on the substrate S in step b) of the process faces the magnetic field generating device 101 of the magnetic block 102 of the conveying device 100.

In step d) of the process in Figure 7, the coating composition 200 is cured to a second dry state, in which the pigment particles are fixed. Curing is performed using a UV lamp 202. As a result, each pattern F1-F3 coated in step b) is cured into the security elements A-C. Thus, a substrate S with at least N security features 4 is obtained. By dividing the substrate between the N security features 4, N banknotes 1 can be obtained.

As defined herein, a secure document (banknote 1) includes a security feature 4. A security feature 4 comprises multiple security elements (multiple OELs) A-C, characterized by (i) their shape (patterns F1-F3) and (ii) the magnetic effects G1-G3 applied to them by corresponding magnetic field generating devices 101. In a non-cured state, a coating composition 200 comprising pigment particles is coated onto a substrate S in the form of patterns F1-F3, each cured pattern forming a security element A-C. Security elements A-C may be spaced apart or at least partially adjacent (i.e., at least partially in contact with each other).

Figure 8 schematically illustrates an example of a printing press 500 performing the process of Figure 7 to produce at least N security documents 1. As can be seen in Figure 8, a sheet of paper S is inserted and guided through the printing press 500. The sheet of paper S has N independent and spaced-apart multi-layers 203 of coated pattern (each including pattern F1-F3, therefore the multi-layer is a triplet here), which together form the coating composition 200. The pattern triplets 203 are coated by a screen printing device 204 (corresponding to step b) of Figure 7. In the example of Figure 8, the printing press 500 includes a magnetic field generating device 201 for generating a time-correlated magnetic field to biaxially orient the pigment particles before the paper S reaches the conveying device 100 (step f in Figure 7). As shown in Figure 8, the cylindrical conveying device 100 rotates, thereby guiding the paper S through the printing press 500.

The distance between the magnetic blocks 102 is the same as the distance between the pattern multiply 203, so each magnetic block 102 orients the pigment particles of the pattern multiply 203 it faces. The ultraviolet lamp 202 is positioned such that curing (step d in Figure 7) and the step of orienting the pigment particles (step c in Figure 7) are performed simultaneously.

Figure 9 shows a variation of the printing press 500 in Figure 8, wherein the magnetic field generating device 201 for generating a time-correlated magnetic field to biaxially orient pigment particles is configured to face the cylindrical conveying device 100.

Figure 10 shows another variation of the printing press 500 of Figures 8 and 9, which includes two magnetic field generating devices 201 of Figures 8 and 9 for generating time-correlated magnetic fields, which are used for biaxial orientation of pigment particles.

The subject matter disclosed above should be considered illustrative rather than restrictive, and is intended to provide a better understanding of the invention as defined in the independent claim.

1: Banknote 2: Opaque Area 3: Transparent Area 4: Security Feature 100: Transmission Device 101: Magnetic Field Generating Device 102: Magnetic Block 103: Alignment Line 104: Edge Magnetic Block 105: Shielding Element 106: Compensating Magnetic Block 107: Additional Compensating Magnetic Block 108: Compensating Magnetic Field Generating Device 109: Additional Compensating Magnetic Field Generating Device 200: Coating Composite 201: Time-Related Generation Magnetic field generating device 202: Ultraviolet lamp 203: Pattern multi-body 204: Screen printing device 300: Magnetic orientation device 301: Housing 302: Cover 500: Printing press A-C: Safety element or optical effect layer (OEL) BE: Trailing edge FE: Leading edge F1-F3: Pattern G1-G3: Magnetic effect R1-R8: Column S: Substrate Y1-Y6: Row

Figure 1 shows an example of a substrate for printing banknotes; Figures 2a and 2b show examples of banknotes; Figure 3 shows a conveying device; Figure 4 shows a cross-section of the conveying device according to the first embodiment; Figures 5a and 5c show magnetic orientation units; Figure 6 shows a cross - section of the conveying device according to the second embodiment; Figure 7 shows a method for generating security documents; Figure 8 schematically shows a first example of a printing press; Figure 9 schematically shows a second example of a printing press; and Figure 10 schematically shows a third example of a printing press.

1: Banknotes

2: Opaque Areas

3: Transparent Areas

R1-R8: Columns

S:Substrate

Y1-Y6: Rows

BE: Back Edge

FE: Leading edge

Claims (15)

A conveying device (100) for orienting sheet-like magnetic or magnetizable pigment particles contained in a radiation-curable coating composition (200) and coated on a substrate (S), the conveying device (100) being a flat conveying device (100) or a cylindrical conveying device (100), the conveying device (100) comprising: N identical magnetic blocks (102) aligned along an alignment line (103) disposed on an outer surface of the conveying device (100), the... Each of the magnetic blocks (102) includes M magnetic field generating devices (101), each of which generates a corresponding magnetic field, such that each of the magnetic blocks (102) generates a block magnetic field, where N is greater than or equal to two and M is greater than or equal to one; and a shielding element (105) disposed between every two adjacent magnetic blocks (102), the shielding element (105) being made of a material that at least partially isolates the block magnetic field of each magnetic block (102) from the block magnetic fields of other magnetic blocks (102). The transmission device as described in claim 1 further includes N housings (301) for each housing a magnetic block (102), at least a section of the housings (301) forming the shielding element (105). The transmission device as described in claim 1 or 2, wherein the material of the shielding element (105) is a material having a relative permeability greater than 40; and/or steel, particularly S235 steel. The conveying device described in claim 1, wherein: the conveying device (100) is the cylindrical conveying device (100) and the alignment line (103) is an outer circumference of a cross section of the cylindrical conveying device (100); or a side line on the outer surface of the cylindrical conveying device (100), the side line being parallel to an axis of the cylindrical conveying device (100); or the conveying device (100) is the flat plate conveying device (100) having a rectangular shape and the alignment line (103) being parallel to one side of the rectangular flat plate conveying device (100). A conveying device (100) is used to orient sheet-like magnetic or magnetizable pigment particles contained in a coating composition (200) and coated on a substrate (S) to generate N security documents (1) on the substrate (S). The conveying device (100) is a flat conveying device (100) or a cylindrical conveying device. The conveying device (100) includes: N identical magnetic blocks (102) aligned along an alignment line (103) disposed on an outer surface of the conveying device (100). Each of the magnetic blocks (102) includes M magnetic field generating devices (101), each of the magnetic field generating devices (101) generating a corresponding magnetic field, such that the magnetic... Each of the N magnetic blocks (102) generates a magnetic field, where N is greater than or equal to two and M is greater than or equal to one; and a compensating magnetic block (106) is disposed next to the first magnetic block (102) along the alignment line (103), such that the first of the N magnetic blocks (102) is positioned between the compensating magnetic block (106) and the N magnetic blocks. Between the second of the blocks (102), the compensating magnetic block (106) includes at least one compensating magnetic field generating device (108), which provides a magnetic field that is the same as the magnetic field of at least a portion of one of the magnetic blocks (102), which includes the Mth magnetic field generating device (101). The transmission device as described in claim 5 further includes an additional compensating magnetic block (107) disposed next to the Nth magnetic block (102) along the alignment line (103), such that the Nth magnetic block (102) is positioned between the additional compensating magnetic block (107) and the (N-1)th magnetic block (102). The additional compensating magnetic block (107) includes at least one additional compensating magnetic field generating device (109), which provides a magnetic field that is the same as the magnetic field of at least a portion of one of the magnetic blocks (102), which includes the first of the M magnetic field generating devices (101). The transmission device as described in claim 5 or 6, wherein a magnetic field provided by the at least one compensating magnetic field generating device (108) included in the compensating magnetic block (106) is the same as the magnetic field of the Mth magnetic field generating device (101), and/or a magnetic field provided by the at least one additional compensating magnetic field generating device (109) included in the additional compensating magnetic block (107) is the same as the magnetic field of the first magnetic field generating device (101). The transmission device as described in claim 5 further includes a shielding element (105) disposed between every two adjacent magnetic blocks (102) and between the compensating magnetic block (106) and the first of the N magnetic blocks (102), the shielding element (105) being made of a material that at least partially isolates the block magnetic field of each magnetic block (102) from the block magnetic fields of the other magnetic blocks (102) and from the magnetic field of the compensating magnetic block (106). The transmission device as described in claim 1, wherein each magnetic block (102) includes at least two different magnetic field generating devices (101). A magnetic orientation unit (300) for use in a transmission device (100) as described in any of claims 1 to 9, the magnetic orientation unit (300) being used to orient sheet-like magnetic or magnetizable pigment particles contained in a radiation-curable coating composition (200) and coated on a substrate (S), the magnetic orientation unit (300) comprising: a magnetic block (102) including M magnetic field generating devices (101), each of the magnetic field generating devices (101) generating a corresponding magnetic field, such that the magnetic block (102) generates a magnetic field, wherein M is greater than or equal to one; and a shielding element (105) and/or a compensating magnetic block (106); wherein the shielding element (105) is disposed next to the magnetic block (102), the shielding element (105) is made of a material that at least partially blocks the magnetic field of the block; and/or the compensating magnetic block (106) is disposed next to the first magnetic block (102), the compensating magnetic block (106) includes at least one compensating magnetic field generating device (108), the magnetic field provided by the at least one compensating magnetic field generating device (108) is the same as the magnetic field of at least a portion of the magnetic block (102) including the Mth magnetic field generating device (101). A printing press (500) comprising one of the conveying devices (100) as described in any one of claims 1 to 9. A method for generating at least N security documents (1), each of which includes a security feature (4), the security feature (4) comprising at least M security elements (A-C), where N is equal to or greater than two, and M is greater than or equal to one, the method comprising the steps of: a) providing a substrate, preferably in the form of a sheet of paper; b) coating a surface of the substrate with a radiation-curable coating composition (200) comprising sheet-like magnetic or magnetizable pigment particles, the coating composition (200) being in a first state, the coating composition (200) being coated with each of the N security features (4) in the form of M independent and optionally spaced patterned designs (F1-F3); c) The magnetic or magnetizable pigment particles are exposed to a magnetic field of one of the conveying devices (100) as described in any of claims 1 to 9, so as to orient at least a portion of the sheet-like magnetic or magnetizable pigment particles of each of the M coated pattern (F1-F3) of a safety feature (4) according to a magnetic field of a magnetic block (102) of the conveying device (100); and d) preferably simultaneously with part of step c) the coating composition (200) of step b) is cured to a second state to fix the sheet-like magnetic or magnetizable pigment particles in their adopted positions and orientations, such that each cured pattern forms one of the safety elements (A-C). The method described in claim 12 further includes the following steps: e) dividing the substrate (S) among the N security features (4) to obtain individual and identical security documents (1). The method as described in claim 12 or 13, wherein each of the N security features (4) includes at least two different security elements (A-C). The method as described in claim 12, wherein the method further includes the following step f): between step b) and step c), exposing the sheet-like magnetic or magnetizable pigment particles to a time-correlated magnetic field to pre-orient the sheet-like magnetic or magnetizable pigment particles in a biaxial manner.