Printing press for producing security documents
By combining a printing press with microlenses and a special printing fluid, the problem of achieving multi-angle dynamic effects and machine readability in existing technologies for secure documents has been solved, thus realizing dynamic effects and machine readability for secure documents.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KOENIG & BAUER AG
- Filing Date
- 2023-04-06
- Publication Date
- 2026-05-05
AI Technical Summary
Existing technologies make it difficult to effectively combine microlenses and printed patterns in the production of security documents to achieve dynamic effects and machine readability under multi-angle observation.
By combining microlenses with printed patterns using a printing press, dynamic effects are presented at different angles through an optical imaging structure, and machine readability is achieved by using a special printing fluid that is readable in the non-visible spectrum.
It achieves dynamic effects and machine readability when the secure document is viewed from different angles, thus enhancing the anti-counterfeiting performance of the secure document.
Smart Images
Figure CN118574730B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a printing press for producing security documents according to claim 1. Background Technology
[0002] A method for forming a structure of microprime is known from US2021 / 0206192A1, wherein the microprime is variable in its material composition. The method includes the steps of: applying a first region of a layer made of a first material to a surface of a first material carrier; applying a second region of a layer made of a second material different from the first material to a surface of a second material carrier; mixing the first and second regions of the first and second materials such that the mixed region of the first and second materials exhibits a gradual change in the relative concentration of the first and second materials along a first direction; the step of mixing the first and second regions of the first and second materials includes: contacting a first mixed surface with a first material on the surface of the first material carrier; and making the first mixed surface... The mixing surface moves relative to the surface of the first material carrier along a direction corresponding to a first direction so that the layers of the first material are distributed along the direction corresponding to the first direction, and the second mixing surface contacts the second material on the second material carrier, and the second mixing surface moves relative to the surface of the second material carrier along a direction corresponding to the first direction so that the layers of the second material are distributed along the direction corresponding to the first direction; the mixed layer of the first and second materials contacts a patterned material carrier in the mixing region, the surface of the patterned material carrier defining a pattern corresponding to the structure of the micro-primitives, the patterned material carrier selectively removing the first and second materials according to the pattern at least in the mixing region; the mixed layer of the first and second materials defining the micro-primitive array is transferred onto the carrier layer.
[0003] EP2493700A2 discloses a method for manufacturing a safety device, the method comprising: providing an arrangement of lenticular focusing elements on one side of a transparent substrate; and providing a corresponding arrangement of stripe groups on the other side of the transparent substrate, the stripes and the lenticular focusing elements defining a lenticular device such that, in different viewing directions, the corresponding stripes from each group can be viewed through the corresponding lenticular focusing elements.
[0004] A method for producing a safety element or safety document is known from DE102017218800B3, wherein the safety element or safety document has a structure of multiple microlenses forming an optical imaging structure in the form of a geometric shape. A first subset of these microlenses arranged on the surface of the geometric shape is arranged in a grid composed of grid cells, wherein the microlenses arranged in the grid are respectively rotationally symmetrically spherical or rotationally symmetrically aspherical. A second subset of the microlenses belonging to the associated optical imaging structure are arranged in the same geometric shape in at least one lens grid having multiple microlenses respectively designed in a rod-like, axisymmetric manner. A substrate is printed simultaneously and / or at the same printing location on a first side by at least one printing mechanism with multiple superimposed sub-printed patterns. An optical imaging structure including microlenses is applied inline on the same or other side of the substrate by a spraying device.
[0005] A secure document is known through WO2011 / 107783A1, comprising: a document substrate having at least two transparent or see-through windows spaced apart from each other, and means comprising the transparent substrate, the transparent substrate carrying: i) a uniform arrangement of micro-focusing elements on a first surface, wherein the focusing elements define a focal plane; ii) micro-primitives of a first color and a corresponding first arrangement located in a plane substantially coinciding with the focal plane of the focusing elements; and iii) micro-primitives of a different color and a corresponding second arrangement located in a plane substantially coinciding with the focal plane of the focusing elements, wherein the pitch of the micro-focusing elements and the first and second arrangements of the micro-primitives and their relative positions such that: the micro-focusing elements The arrangement of the components corresponds to each of the first and second arrangements of micro-primitives to generate a corresponding enlarged version of the micro-primitives for each arrangement according to the moiré effect; and at least one segment of the first arrangement of micro-primitives does not overlap with the second arrangement of micro-primitives, and at least one segment of the second arrangement of micro-primitives does not overlap with the first arrangement of micro-primitives; wherein the means is processed into or applied thereon in alignment with at least two windows, the means being registered relative to the document substrate such that an enlarged version of the first micro-primitive arrangement is visible through the first window of the two windows, and an enlarged version of the second micro-primitive arrangement is visible through the second window of the two windows, the transition between the two micro-primitive arrangements being occluded by the document substrate between the two windows.
[0006] A lens array for imaging multiple primitives in an object plane is known from DE112010000957T5. This lens array comprises multiple microlenses arranged in a transparent or translucent material having primitives on opposite sides, or on one side. The lens array has a measured thickness corresponding to the distance from the vertex of each microlens to the object plane. Each microlens has a set of lens parameters, wherein the measured thickness and / or at least one lens parameter are optimized such that the focal size of each microlens in the object plane is substantially equal to, or deviates from, the size of the primitive in the object plane by a predetermined amount. Here, the measured thickness of the lens array is preferably less than the focal length of all the microlenses. The primitives may, for example, be assumed to be in the form of points or lines. The lens array of DE112010000957T5 is designed such that: in the cone or angular field of light incident on the relevant microlens in the direction toward the primitive, parallel to the main plane of the respective microlens, there is always only one primitive arranged side by side with each other, so that for a viewer viewing the printed image from a specific viewing angle, only a single frame can always be perceived at a certain point in time. Summary of the Invention
[0007] The purpose of this invention is to provide a printing press for producing secure documents.
[0008] This objective is achieved by a printing press having the features of claim 1. The dependent claims illustrate advantageous designs and / or improvements to the discovered solution. Attached Figure Description
[0009] An embodiment is shown in the accompanying drawings.
[0010] in:
[0011] Figure 1 A security document showing a security element with an optical imaging structure is displayed.
[0012] Figure 2 A strongly magnified cross-sectional view is shown of an arrangement having at least one printed pattern and individual plano-convex microlenses integrated into an optical imaging structure, wherein light is incident from a first viewing angle.
[0013] Figure 3 Showing according to Figure 2 The arrangement is such that light enters from a second viewing angle.
[0014] Figure 4 It shows security documentation for an organization that uses self-verification;
[0015] Figure 5 The security document is shown on the back with enhanced contrast;
[0016] Figure 6The back is shown with enhanced contrast, and the security documents for the self-verification mechanism are displayed.
[0017] Figure 7 Showing in particular according to Figure 5 A simplified diagram of a printing press used to produce secure documents, or 6. Detailed Implementation
[0018] In optics, the term "lens" refers to a structural element that is transparent to light and has at least one light-refracting surface arranged in the optical path of light. Here, "light" refers to the visible portion of electromagnetic radiation. In the electromagnetic spectrum, light ranges from approximately 380 nm (violet) to 780 nm (red). The following is based on converging lenses, which are lenses that converge incident light, particularly plano-convex lenses. Preferred configurations are, on the one hand, rotationally symmetric lenses with a spherical or aspherical design, and on the other hand, axisymmetric rod lenses, wherein the respective axes of symmetry of the relevant lenses are aligned with their optical axes. Thus, the optical axis is generally a straight line extending through the center of curvature of a convex lens surface. For a flat lens surface, the optical axis is perpendicular to the lens surface. The curvature of a refracting, for example, convex surface is given by its radius of curvature, the origin of which lies on the optical axis. A flat lens surface is defined by an infinitely large radius of curvature.
[0019] Rod lenses are designed in the form of straight cylindrical or elliptical cylinders, each bisected by half the length of the rod, wherein the corresponding axis of symmetry of such lenses extends orthogonally to the corresponding rod length. In the case of spherical lenses, the refractive surface is designed as a segment of surface composed of spheres, i.e., in the form of a dome. Aspherical lenses have at least one refractive surface that deviates from a spherical or planar shape. The shape of rotationally symmetric aspherical lenses is usually given in the form of conic sections (circles, ellipses, parabolas, hyperbolas) plus a correction polynomial of higher-order deformation.
[0020] A lens has two surfaces that intersect the optical path of light, known as its envelope. For the purpose of light beam focusing, the definition applicable is that light enters a convex lens with a plano-convex construction on its convex, curved envelope, and exits the lens on its flat envelope. The envelope is the interface between different media in which light propagates. One of these media is formed by a material, namely the material of the relevant lens. At least one other medium is the space where the relevant lens is located, typically filled with air. Because the optical material properties of at least two media arranged in the optical path differ from each other, light is refracted at the interface between these adjacent media. Therefore, light refraction occurs on at least one envelope of the respective lens, particularly on its curved envelope. The optical material properties associated with the refraction of light are represented by the corresponding refractive index of the relevant medium. The refractive index is a dimensionless physical quantity that indicates by what factor the wavelength and phase velocity of light in the relevant medium are smaller than in vacuum. Of the two media with different refractive indices forming a common interface, the medium with the higher refractive index is called the optically denser medium. The Abbe number (also known as the Abbe number) is a dimensionless quantity that characterizes the optical dispersion properties of a lens and indicates the degree to which its refractive index varies with the wavelength of light. The ability of a lens to produce an optical image of an object viewed through it depends on the refractive index of the lens material and the shape of the envelope surface that forms the interface between different media.
[0021] The principal plane of a lens is a plane arranged orthogonally to the axis of symmetry of the relevant lens within the structural element. In the case of a thin lens, where its maximum extension along the axis of symmetry—that is, the thickness of the lens—is considered very small compared to the radius of curvature of the convex envelope surface, since the radius of curvature of the convex envelope surface is, for example, at least five times larger than the thickness, a single principal plane is sufficient as a basis for obtaining sufficiently accurate observations of the characteristics of the relevant lens. In a plano-convex lens, this principal plane coincides with the flat lens surface. The focal length of a lens is the distance between the principal plane of the relevant lens and its focal point (focal point), where the focal point is understood here as the intersection of parallel rays incident into the lens and converged by the lens. Here, the parallel rays incident into the lens are not necessarily parallel to their optical axes, but rather at an arbitrary, particularly acute, angle of incidence relative to the principal plane of the relevant lens. The plane arranged orthogonally to the optical axis at the focal point is called the focal plane.
[0022] The envelope of a lens for light incidence has two opposing edge points, for example, located in the principal plane of the lens, that define the envelope with respect to its optical axis. The distance between these two edge points determines the width of the lens (=lens width). The aperture or opening width of a lens refers to its free opening or diameter through which light can be received unobstructed and is at most equivalent to the lens width. The point where the optical axis intersects with the envelope of the lens for light incidence is called a vertex. This vertex is arranged on the envelope for light incidence that is furthest from the focal point of the lens.
[0023] A rotationally symmetric lens with a spherical or aspherical construction focuses incident light into a cone or conical shape, wherein the diameter of the base of the cone or conical shape is approximately equal to the width of the lens, and the height perpendicular to the base of the cone or conical shape is approximately equal to the focal length of the lens. An axisymmetric lens with a rod-like design focuses incident light into an acute-angle field, the origin of which is located at the focal point of the lens. Numerical aperture represents the ability of a lens to focus light. Numerical aperture determines the minimum size of the spot that can be produced at its focal point, and is therefore an important parameter limiting resolution.
[0024] Multiple lenses, each rotationally symmetrically constructed in a spherical or aspherical shape, form a lens grid, also known as a lens array. These lenses are arranged in a preferably uniform grid composed of square or hexagonal grid cells, particularly without gaps or overlaps. Multiple lenses, each axisymmetrically constructed in a rod-like shape, form a lens grid, also called a biconvex lens, wherein the lenses are arranged side-by-side with their respective rod lengths orthogonal, preferably without gaps or overlaps. Multiple lenses arranged in a grid-like lens grid and / or multiple lenses arranged in a lens grid, in their respective combinations, form optical imaging structures in geometric form, extending on flat or curved surfaces. The surfaces of the optical imaging structure can have any shape, such as rectangular, circular, elliptical, or polygonal. In geometry, a geometric figure is considered as a set of points. Referring to the optical imaging structure, at least one lens is arranged on a subset of the points forming the geometric figure.
[0025] In an optical imaging structure, only one or more lens grids, each in a grid-like configuration, or only one or more lenses arranged within a lens grid, and both of these lens arrangements can be mixed together with their respective different lens arrangements, such that the grid-like lens grids and the lenses arranged within the lens grids are arranged together in the same optical imaging structure. For example, the lens grids constructed in the relevant optical imaging structure can each have different orientations, wherein the corresponding orientation of the relevant lens grid is determined by the corresponding direction of the rod length of the lens involved in the structure of the relevant lens grid.
[0026] Microlenses are miniaturized forms of traditional lenses. The term "microlens" is used to refer to lenses with a width less than 100 μm, preferably in the range of 20 μm to 65 μm. The focal length of a microlens is less than, for example, 100 μm, preferably a maximum of 95 μm. Microlenses can now be industrially produced. Microlenses made of synthetic materials or resins can be produced, for example, using (spray coating) casting methods, (spray coating) embossing methods, or printing methods. Optical imaging structures composed of microlens meshes are also called micro-optical structures.
[0027] When an optical imaging structure, particularly formed by microlenses, is arranged in combination with a printed image preferably composed of a flat surface, different effects can be produced for an observer viewing the printed image through the optical imaging structure by applying the optical imaging structure, for example, to a substrate having the printed image. For example, an arrangement consisting of at least one printed image and at least one optical imaging structure can be used, such as so-called transforming images or shaky images (flips) and / or spatial images, i.e., achieving three-dimensional effects and / or distortion effects and / or scaling effects and / or animation. These effects can be perceived without optical aids when the observer alternately views the printed image from different viewing angles. The sensory experience presented to the viewer through different viewing angles is also called a biconvex lens image.
[0028] Generally, planar printed images are preferably printed on a two-dimensional substrate, for example, preferably manufactured by a printing machine during industrial production. The substrate is, for example, a web of printing material or designed for printing on single sheets of paper. Therefore, the printed image is applied to the substrate, for example, in a dotted or linear grid. Thus, the printed image consists, for example, of multiple, particularly a large number of pixels and / or lines. Here, the pixel size or line thickness is less than 100 μm, preferably less than 50 μm, particularly less than 20 μm, for example, in the range of about 5 μm to 10 μm. In the following, it is assumed that the pixel size and / or line thickness of the pixels constituting the printed image used with an optical imaging structure (e.g., an optical imaging structure) are, for example, at most as large as, preferably smaller than, and particularly less than half of, the corresponding lens width involved in the construction of the relevant optical imaging structure.
[0029] In optics, resolution is the ability to distinguish fine structures; that is, the minimum distance between two pixels or two lines in order to be perceived as separate pixels or lines. The resolution of the human eye varies from person to person. An adult with normal vision can typically distinguish structures 150 micrometers apart at a distance of 25 centimeters. This corresponds to a viewing angle of approximately 2 arcminutes, known as angular resolution. In low-contrast environments, human vision deteriorates significantly, becoming the reciprocal of resolution. The lens width of a microlens is typically smaller than the resolving power of the human eye in an adult with normal vision.
[0030] To produce a color print, the substrate is printed with various printing inks, such as primary colors red, green, and blue, and, if necessary, black. A print typically consists of an arrangement of multiple small-area pixels at different locations within the print, each pixel preferably having multiple pixels or lines, and generally extending less than 100 μm in length. Each pixel or group of adjacent pixels, for example, forms an object observable through a lens. The individual pixels in the print are generally arranged to form the printed subject matter that defines the information content of the print. Due to their limited, generally insufficient resolving power, the individual pixels used in conjunction with microlenses are usually imperceptible to the naked eye. The color impression of a print, or at least a segment thereof, perceived by a person is achieved through additive color mixing of pixels and / or lines printed with different inks in the relevant pixels, occurring in the viewer's eye and brain. The superposition of two primary colors produces the color impressions of yellow, cyan, and magenta, called secondary colors. The superposition of all three primary colors produces the impression of white. Color registration, i.e., the matching degree of the printing plates, i.e. the accuracy of the matching of pixels and / or lines of different printing inks in their relative arrangement, is less than 20 μm, preferably less than 10 μm, and particularly in the range of about 5 μm in the embodiments of the present invention.
[0031] The optical imaging structure configured in conjunction with the embodiments of the invention considered herein is preferably arranged in combination with pixels and / or lines of different printing inks. The printed image is preferably generated as or by superimposing multiple sub-printed images, wherein each sub-printed image, for example, is printed with different printing inks. Superposition can be achieved by sequentially overprinting onto a substrate or preferably by collecting the sub-printed images on a printing element (e.g., a roller) and simultaneously conveying them to the substrate. The sub-printed images are further composed of pixels and / or lines, the pixel size of which and / or the line thickness of the associated lines being in the micrometer range, for example, on the micrometer scale, such as in the range of less than 20 μm. For a viewer viewing the printed image, in terms of their sensory perception, the superposition of the multiple sub-printed images involved in the printed image, for example, forms an overall color impression.
[0032] An arrangement comprising at least one printed image and at least one optical imaging structure enables a viewer viewing the printed image to perceive multiple distinct individual images from different viewing angles, wherein a series of individual images are perceived by the viewer as alternating or shaky images (flipped) and / or spatial images, i.e., three-dimensional effects and / or distorted effects and / or scaling effects and / or animation. Each of these individual images is also referred to as a frame. The images perceived by the viewer at a defined viewing angle are generated by the optical imaging structure from a set of sub-printed images, derived from multiple sub-printed images perceptible at corresponding positions of microlenses based on at least one or more primitives therein, wherein the overall color impression associated with the position of the printed image is generated by superimposing all sub-printed images present and perceptible at that position. Thus, the optical imaging structure arranged in combination with the printed image is an optical mask of the sub-printed images of the associated printed image, arranged in a surface-overlapping manner with the optical imaging structure.
[0033] To allow viewers of a printed image to simultaneously see multiple frames at a defined viewing angle, such as to enable more complex and / or differentiated animations, an arrangement is employed, for example, of a printed image and an optical imaging structure composed of a grid of multiple plano-convex microlenses. This arrangement includes multiple, preferably more than three, particularly five to ten primitives arranged side-by-side below at least one microlens of the associated optical imaging structure. These primitives are arranged between the lens width extension of the associated microlens and their focal points in a sectional plane parallel to the principal plane of the associated microlens. This sectional plane intersects with cones or angular fields of light incident through the lens width of the associated microlens toward the side-by-side primitives. Within the sectional plane, multiple distinct primitives are simultaneously arranged side-by-side within the cones or angular fields.
[0034] Thus, an arrangement is obtained having a printed pattern and an optical imaging structure composed of a plurality of plano-convex microlens grids, each of which has a lens width along the printed pattern preferably less than 100 μm, wherein the printed pattern has a plurality of elements, wherein a plurality of elements are arranged below at least one microlens of the associated optical imaging structure, the plurality of elements arranged below at least one microlens of the associated optical imaging structure are arranged side by side along the lens width and extend in the lens width direction at a length shorter than the associated lens width, wherein a plurality of, preferably at least three, particularly more than three, distinct elements are arranged side by side in a sectional plane in the cone or angular field of light incident on the principal plane of the associated microlens in the direction of the lens width of the associated microlens toward the adjacent elements, between the extension of the lens width of the associated microlens and its conical or angular focal point, and in the direction of the light incident on the principal plane of the associated microlens. With this arrangement, viewers of the printed image can perceive multiple frames simultaneously from a certain viewing angle, which produces complex and / or differentiated animations, as well as smooth color transitions when sliding through the corresponding color-designed primitives, and / or smooth frame transitions when the primitives form different printed themes.
[0035] The substrate is, for example, a fibrous printing material, particularly paper or film, preferably a polymer film. The substrate can be opaque or transparent. The substrate can be designed as a single layer or multiple layers, particularly segmented in a multi-layered design. Different layers in a multi-layered substrate can be made of different materials, for example, one layer of paper and another layer of polymer film. The substrate, or at least one corresponding layer of the substrate, has a material thickness, i.e., for example, less than 100 μm, preferably less than 50 μm, particularly about 25 μm. The printed image formed on the substrate has a layer thickness, for example, less than 10 μm, preferably less than 5 μm, particularly in the range of 1 μm to 2 μm. The substrate can be printed on one or both sides.
[0036] In a preferred embodiment of the invention, the arrangement of the printed image and the optical imaging structure is part of a security element or document, particularly a security document. These documents include, for example, banknotes, credit cards, checks, securities, stocks, passports, identity cards, driver's licenses, property certificates, travel documents (e.g., airline or train tickets), tickets, educational certificates, and other official or formal documents such as birth, death, or marriage certificates. This list is merely illustrative and not exhaustive. However, banknotes are preferred.
[0037] Figure 1Example illustration shows document 02, particularly security document 02, on which at least one security element 01 is arranged. Document 02 and / or the associated security element 01 have at least one optical imaging structure 03 on a portion or the entire surface of its surface, wherein the corresponding optical imaging structure 03 is preferably designed as a micro-optical structure 03 formed by microlenses 11. The associated optical imaging structure 03 is arranged such that it at least partially covers, for example, the printed image 27 constructed or applied to document 02.
[0038] Figure 2 Example: a significantly enlarged sectional view, especially as Figure 1 The partial view of security element 01 or document 02 shows an arrangement with a single plano-convex microlens 11, which is integrated into an assembly of microlenses 11 or arranged in a grid. Each associated microlens 11 has an axis of symmetry 12 that also forms the optical axis 12 of the microlens 11. The microlens 11 can be designed rotationally symmetrically as a spherical or non-spherical shape, or it can be designed, for example, axisily symmetrically as a rod, with the axis of symmetry 12 extending orthogonally to the length of the rod for an axisily symmetrically rod-shaped microlens 11. The microlens 11 is made, for example, from a transparent synthetic material or resin by injection molding, casting, die casting, or printing. The microlens 11 has a convex envelope surface 13 for light incidence, onto which a beam of, for example, parallel light rays 14 is incident. Microlens 11 has two opposing edge points 16; 17 that define the convex envelope 13, symmetrically with respect to its optical axis 12 passing through the vertex 37 of the convex envelope 13. The distance between the two edge points 16; 17 determines the width of microlens 11, referred to as lens width 18. The lens width 18 of microlens 11 is less than 100 μm. The two edge points 16; 17 of the convex envelope 13 lie in a plane orthogonal to the optical axis 12 of the associated microlens 11, which is also called the principal plane 19 of the microlens 11. Figure 2 In the illustrated embodiment, the principal plane 19 forms a flat envelope 21 of the associated microlens 11. The distance between the principal plane 19 of the microlens 11 and its focal point 23 (focal point) forms the focal length 22 of the associated microlens 11, where the focal point 23 is the intersection of the bundled, particularly parallel, light rays 14 incident into the microlens 11. The focal length 22 of the microlens 11 is less than 100 μm. The plane orthogonally arranged at the focal point 23 to the optical axis 12 is called the focal plane 24.
[0039] exist Figure 2In the illustrated embodiment, the microlens 11 is part of a lens array or lens grid in which a large number of microlenses 11 are arranged, preferably without gaps and without overlap, in relation to defined surfaces of arbitrary profiles. The lens array or lens grid is arranged on a substrate 26, which is designed, for example, as a fibrous printing material with transparent windows, particularly paper, or as a film, preferably a transparent polymer film. The substrate 26 has a material thickness 29, for example less than 100 μm, preferably less than 50 μm, particularly about 25 μm. The substrate 26 is preferably part of a security element 01 or document 02, particularly a security document 02. The substrate 26 is designed to be transparent at least in the area covered by the flat envelope surface 21 of the respective microlens 11.
[0040] exist Figure 2 In the illustrated embodiment, a printed pattern 27 with a small layer thickness 36, for example less than 10 μm, is applied on the back side of the substrate 26, i.e., on the side of the substrate 26 facing away from the microlens 11. This printed pattern 27 has a large number of individual, distinct primitives 28. These individual primitives 28 are designed to be very small in area and extend parallel to the lens width 18 in only a few micrometers, for example, at a maximum of 10 μm. Thus, it is feasible for multiple, for example, ten such primitives 28a-28j to be arranged, for example, side by side, in the area covered by the flat envelope surface 21 of the microlens 11. At least one of these primitives 28a-28j preferably has pixels and / or lines printed with different printing inks, and in particular, depending on the number of primitives 28a-28j arranged side by side, their respective pixels have a pixel size 38 and / or their lines have a line thickness 38, respectively in the range of a few micrometers, preferably in the range of less than 20 μm. The printed pattern 27 is preferably composed of the overprinting or superposition of multiple sub-printed patterns, each printed with different printing inks. In the area covered by the flat envelope 21 of the microlens 11, i.e., below the respective microlens 11, the graphic elements 28a-28j arranged side by side preferably correspond to different printing subjects.
[0041] Below the respective microlens 11, the elements 28a-28j arranged side-by-side are advantageously positioned closer to the microlens 11 than to its focal point 23. These elements 28a-28j are preferably arranged between the respective microlens 11 and its focal point 23 in a cutting plane 31 parallel to the principal plane 19 of the respective microlens 11. This cutting plane 31 intersects with the cones 32 or angular fields 32 of light incident through the lens width 18 of the respective microlens 11 toward, for example, the elements 28a-28j arranged side-by-side. Preferably, multiple elements 28a-28j are simultaneously arranged side-by-side within the intersecting plane 31 of the cones 32 or angular fields 32. Figure 2In the illustrated embodiment, within the cone 32 or angular field 32, for example, five primitives 28c to 28g are arranged side-by-side. Conversely, the remaining primitives 28a, 28b, and 28h to 28j, arranged in the area covered by the flat envelope 21 of the microlens 11, are imperceptible to a viewer viewing the printed image 27 at a first viewing angle 33, for example, an acute angle, corresponding to the incident light ray 14. If, for the viewer viewing the printed image 27, the viewing angle now becomes a second viewing angle 34, different from the first viewing angle 33, for example, an obtuse angle, then the primitives 28a-28j that can be perceived by the viewer also change. This is in Figure 3 As shown in the figure, it has the same Figure 2 The same arrangement, featuring printed diagram 27 and an optical imaging structure 03 composed of multiple plano-convex microlenses 11, is used. Because the second viewing angle 34 differs from the first viewing angle 33, in… Figure 3 In the embodiment shown, only primitives 28d to 28h are perceptible to a viewer viewing printed image 27, while the other primitives are not perceptible.
[0042] As mentioned, in Figure 2 and Figure 3 The primitives 28a-28j shown, arranged in the area covered by the flat envelope surface 21 of each microlens 11, are formed by pixels and / or lines, preferably printed with different printing inks. Typically, the corresponding pixel size 38 of the associated pixels and / or the line thickness 38 of the associated lines are significantly smaller than the lens width 18 of the corresponding microlens 11, preferably in the range of a few micrometers, particularly in the range of less than 20 μm. Specifically, to make the printed image 27 containing these primitives 28a-28j machine-readable, at least one of these primitives 28a-28j, having pixels and / or lines, is printed using special printing fluids, particularly inks, which differ in their optical properties from common printing fluids, particularly from commonly used printing inks. These special printing fluids are, for example, inks invisible to the naked eye of a normal-vision observer in the absence of excitation located outside the electromagnetic spectrum visible to the human eye, particularly inks that absorb or reflect infrared radiation or convert infrared radiation into visible radiation, or ultraviolet fluorescent inks or magnetic inks. These inks, which are particularly invisible under sunlight, can be detected in different hues, such as blue, green, or red, upon appropriate stimulation, just like other printing inks. The stimulation is preferably electromagnetic or magnetic.
[0043] Here, the term "ink" should be understood to refer to a liquid that intensely dyes and colors, typically consisting of a solution or dispersion of colorants in water or other solvents that are free of binders, or, in the case of inks designed as liquid ink, contain a small amount of binder. Colorants are coloring substances, such as pigments and dyes, which can be inorganic or organic, natural or synthetic. In contrast, printing inks are mixtures containing colorants that are applied to a substrate, that is, transferred to the substrate by means of a printing plate, i.e., transferred to the printing medium. Printing inks contain inorganic and organic pigments, such as titanium dioxide as a white pigment or carbon black as a black pigment, and binders that encapsulate the pigments. Both conventional printing inks and inks, including those invisible to the naked eye under sunlight, can be categorized under the term printing fluid.
[0044] For example, the aforementioned special inks that react with infrared radiation (IR) are used in conjunction with electromagnetic radiation from the near-infrared (NIR) range, wherein radiation with wavelengths in the range of 780 nm to 2000 nm, particularly in the range of 780 nm to 1200 nm, is preferred. Infrared radiation (IR; NIR) reactive inks, for example, contain inorganic, generally pigment-like luminescent materials that emit radiation in the visible spectrum and / or the infrared (NIR) range after absorbing energy. Inks that convert infrared radiation into visible light contain so-called anti-Stokes pigments.
[0045] Ultraviolet radiation, or UV radiation for short, is a type of electromagnetic radiation invisible to the human eye with wavelengths shorter than visible light. According to a widely accepted classification, the ultraviolet spectrum includes wavelengths from 100 nm to 380 nm, spanning from the shortwave range to the boundary of visible light. Inks that emit ultraviolet fluorescence contain fluorescent pigments; when exposed to ultraviolet radiation, these pigments glow intensely, utilizing the ultraviolet rays of sunlight when necessary.
[0046] Magnetic ink is understood to refer specifically to ink mixed with iron oxide particles. These particles can be magnetized by an external magnetic field relative to the associated substrate 26 and optical imaging structure 03, which is different from the Earth's magnetic field, and thus magneto-optical analysis and reading are possible.
[0047] An arrangement advantageous in terms of machine readability, comprising a printed image 27 applied to a substrate 26 and an optical imaging structure 03 covering at least a portion of the printed image 27, is configured such that the optical imaging structure 03 has a group or grid of a plurality of plano-convex microlenses 11, the flat envelope surfaces 21 of which face the substrate 26. The printed image 27 arranged on the substrate 26 is preferably arranged on its side facing the optical imaging structure 03 and has at least one element 28a to 28j, the element having at least one pixel and / or a line, wherein the pixel and / or line is formed by a printing fluid according to a printing technique, the printing fluid being visible to the human eye only based on excitations located outside the electromagnetic spectrum visible to the human eye. The printing fluid is preferably formed as an infrared radiation absorbing ink or an infrared radiation reflecting ink, or an ink that converts infrared radiation into visible radiation, or an ultraviolet fluorescent ink, or a magnetic ink. Thus, the associated at least one element 28a-28j of the machine-readable printed image 27 is an integral part of the integration of associated arrangements, for example, on a security element 01 or document 02, particularly on a security document 02. Excitation of the printing fluid outside the visible electromagnetic spectrum occurs on the front side in relation to the optical imaging structure 03 covering at least a portion of the printed pattern 27, i.e., on the corresponding convex envelope surface 13 pointing to the microlens 11, in which case the excitation is designed to act through the optical imaging structure 03, or the excitation occurs on the back side, i.e. on the substrate side, or on the corresponding flat envelope surface 21 pointing to the microlens 11, in which case the optical imaging structure 03 is designed to block the excitation.
[0048] If it is set that printing fluid visible only to the human eye should not interact with the microlens 11 of the optical imaging structure 03 based solely on excitations located outside the electromagnetic spectrum visible to the human eye, then in such an arrangement, the corresponding pixel size 38 of the line thickness 38 of the associated pixel and / or the associated line z is, for example, larger than the lens width 18 of the corresponding microlens 11.
[0049] Furthermore, it can be configured such that, in a group having multiple plano-convex microlenses 11 or in a grid having multiple plano-convex microlenses 11 at multiple individual locations, a related arrangement consisting of a substrate 26 and an optical imaging structure 03 is provided, in the corresponding optical imaging structure 03, the corresponding microlens 11 remains unconstructed, and at least one element 28a-28j of the printed pattern 27 having at least one pixel and / or line is arranged at the relevant missing portion, the pixel and / or line being constituted, in terms of the printing technology, by a printing fluid that is only visible to the human eye based on excitation outside the electromagnetic spectrum visible to the human eye. Therefore, a printing fluid invisible to the human eye under normal conditions is applied or arranged at selected missing portions in the corresponding optical imaging structure 03.
[0050] As mentioned, the arrangement of the substrate 26 and the optical imaging structure 03 can have a printed image 27, which allows an observer with normal vision viewing the printed image 27 through the optical imaging structure 03 to perceive multiple different single images at different viewing angles. This series of single images is perceived by the viewer as alternating or shaky images (flipping) and / or spatial, i.e., three-dimensional effects and / or distortion and / or scaling and / or animation. These different single images are also referred to as frames. These aforementioned effects are based on multiple sub-printed images, and at least one associated printed image 27 is composed of multiple sub-printed images. To form an arrangement consisting of the substrate 26 and the optical imaging structure 03 having at least one machine-readable printed image 27, it is configured that the associated printed image 27 has multiple sub-printed images at least in the area covered by the optical imaging structure 03. Here, at least one of these sub-printed drawings has primitives 28a-28j, each primitive having at least one pixel and / or one line, the associated pixel and / or associated line being constructed, in terms of printing technology, by printing fluid visible to the human eye only based on excitations located outside the visible electromagnetic spectrum. In an alternative or additional design, it can be configured such that at least one primitive 28a-28j of the machine-readable printed drawing 27 having at least one sub-printed drawing among multiple sub-printed drawings is constructed by a hybrid scheme, wherein the hybrid scheme includes printing fluid visible to the human eye, particularly under daylight conditions, and printing fluid visible to the human eye only based on excitations located outside the visible electromagnetic spectrum.
[0051] Furthermore, in order to form an arrangement having at least one machine-readable printed pattern 27, it can be configured such that, in this arrangement having a substrate 26 having the printed pattern 27 and a structure 03 for optically imaging the printed pattern 27, in a first region covered by the optical imaging structure 03, the elements 28a-28j of the printed pattern 27 arranged therein are respectively visible to the human eye, especially under sunlight conditions, of the printing fluid, and in a second region covered by the optical imaging structure 03, the elements 28a-28j of the printed pattern 27 arranged therein are respectively formed to the human eye-visible printing fluid based only on excitations located outside the electromagnetic spectrum visible to the human eye.
[0052] Regardless of the design and / or construction of the substrate 26, the optical imaging structure 03 thereon, and / or the design of the printing fluid used to form at least one printed image 27, whether the printed image is visible to the human eye, especially under sunlight conditions, or only visible to the human eye based on excitations outside the electromagnetic spectrum visible to the human eye, or for the purpose of forming a security element 01 or a security document 02, the following can be set up to achieve the same printed image 27 using both types of printing fluids described above.
[0053] Figure 4An example of a security document 02, such as a banknote, is shown, whose substrate 26 is made of a fibrous printing material, particularly paper, and has at least one transparent window 04. Alternatively, the substrate 26 of the security document 02 may also be a film, preferably a transparent polymer film or a film with a transparent window 04. On one side of the security document 02, at least in the area of the associated transparent window 04, a micro-optical structure 03 is arranged that partially or completely covers the window 04. This micro-optical structure 03 is designed as a lens array or a biconvex lens, which is composed of plano-convex microlenses 11.
[0054] In the case of lens arrays and, for example, biconvex lenses, these microlenses 11 are rotationally symmetric spherical or non-spherical, for example, axially symmetric rod-shaped designs. Outside the area of the transparent window 04 and spaced apart from it on the other side of the security document 02, i.e., on the side of the security document 02 without the aforementioned lens array or biconvex lens, a printed image 27 is formed or applied, particularly by a printing fluid visible to the human eye, especially under sunlight conditions, or by a printed image visible only to the human eye based on excitations outside the electromagnetic spectrum visible to the human eye. The associated printed image 27 may contain information immediately recognizable to a human or may be designed to be machine-readable. The printed image 27 is applied to the substrate 26 in a grid of elements 28a-28j, for example, in a dotted or linear manner, and preferably in an industrial printing method, such as lithography. The pixel size 38 or line thickness 38 of the primitives 28a-28j applied to the substrate 26 in the printed figure 27 is smaller than the lens width 18 of the microlens 11 arranged in the lens array or biconvex lens, and is therefore significantly smaller than 100 μm, preferably about 20 μm or smaller. If the window 04, which is partially or completely covered by the micro-optical structure 03, also has another printed image 27 on the back side of the substrate 26 of the security document 02, i.e., on the side of the substrate 26 of the security document 02 away from the micro-optical structure 03, preferably also implemented using a lithographic printing method, this other printed image 27 has at least one unprinted surface, i.e., a notch 06, in the area of the other printed image 27 arranged in the area of the transparent window 04, in the area covered by the micro-optical structure 03, such that the relevant notch 06 in the other printed image 27 arranged in the area of the window 04 partially exposes the micro-optical structure 03 applied to the substrate 26 of the security document 02, and opens the view through the transparent window 04 of the corresponding flat envelope surface 21 of the plano-convex microlens 11 arranged in the micro-optical structure 03.
[0055] The method for verifying security document 02 having a micro-optical structure 03 now involves: placing a substrate 26 of security document 02, such as... Figure 4As indicated by the middle arrow, the document is folded at the preferred fold line 07 that runs through the security document 02, and thus, the printed pattern 27, constructed or applied outside and spaced apart from the area of the transparent window 04, overlaps or is at least able to overlap with the micro-optical structure 03 applied to the other side of the substrate 26 of the security document 02, or at least with the notch 06 in the printed pattern 27 arranged in the area of the transparent window 04 that partially exposes the micro-optical structure 03. As shown in Figure 4 As shown, the substrate 26 of the security document 02 is folded at the fold line 07, for example, approximately in half, such that the folded portion of the substrate 26, having printed patterns 27 applied outside and at intervals from the area of the transparent window 04, is placed, or at least can be placed, on another portion having the transparent window 04 and the micro-optical structure 03. By folding the substrate 26 of the security document 02, the printed patterns 27 in the transparent window 04 of the substrate 26 of the security document 02, applied outside and at intervals from the area of the transparent window 04, are placed onto the corresponding flat envelope surface 21 of the plano-convex microlens 11 arranged in the micro-optical structure 03.
[0056] If necessary, by performing relative movement between the micro-optical structure 03 and the printed image 27, which overlaps with and is applied at intervals to the area outside the transparent window 04, or by performing a flipping movement of the entire security document 02 folded on the fold line 07, such that: when viewed from the direction of the convex envelope surface 13 through the fold line towards the associated printed image 27, the printed image 27, or at least the information contained therein, is visible or identifiable, which in Figure 4 For example, it can be indicated by the human-readable symbol "&".
[0057] The advantage of the discovered solution lies in its ability to authenticate secure document 02 without the aid of external means. Therefore, the proposed method enables self-authentication of the relevant secure document 02 solely based on the mechanisms or means inherent in the document itself. Thus, the authentication presented here provides proof that the relevant secure document 02 is an original document, particularly genuine banknotes, that it can be performed anytime, anywhere.
[0058] It can be observed that on the back side of the substrate 26, that is, on the side of the substrate 26 facing away from the micro-optical structure 03, in the area of the transparent window 04, the printed pattern generated by the printing fluid that is generally visible to the human eye, especially under sunlight conditions, is sometimes not sufficiently recognizable when viewed from the direction of the convex envelope surface 13 through the relevant micro-optical structure 03 under weak light, such as dim lighting conditions.
[0059] To improve the legibility of this printed image 27, particularly to the human eye, it is proposed that the printed image 27, generated on the back side of the substrate 26 in the area of the transparent window 04, be overprinted with a printing fluid having a lighter hue than the printing fluid 27 used to generate the associated printed image 27. If the printed image 27 generated on the back side of the substrate 26 in the area of the transparent window 04 is generated by printing fluids of various different hues, then a printing fluid having a lighter hue than the lightest hue of the printing fluid used to generate the associated printed image 27 is used for overprinting the printed image 27 generated in this way. Preferably, the printed image 27 applied on the back side of the substrate 26 in the area of the transparent window 04 is at least partially overprinted with a white ink layer 39. This layer 39 forms a planar extended cover layer composed of light-colored, particularly white, ink for the printed image 27 applied on the back side of the substrate 26 in the area of the transparent window 04. Here, the covering layer can be opaque, meaning it is not transparent to electromagnetic radiation in the wavelength range of approximately 380 nm (violet) to 780 nm (red), or it can be designed to be partially transparent to electromagnetic radiation in the same wavelength range. The partial transparency can be designed to gradually vary along the two-dimensional planar extension of the covering layer, such that some locations are designed to be more transparent than others. The transparency to incident light is preferably in the range of 10% to 90%.
[0060] Therefore, as in Figure 5As shown in the example, a security document 02 is formed having a transparent window 04 constructed in its substrate 26. A micro-optical structure 03, consisting of microlenses 11, is arranged at least on one side of the substrate 26, in the area of the transparent window 04, and at least one printed image 27 is arranged on the opposite side of the substrate 26 to the micro-optical structure 03. Here, the associated printed image 27 has a plurality of primitives 28a-28j in a dotted or linear grid pattern, these primitives 28a-28j being formed in a hue different from white. The pixel size 38 or line thickness 38 of these primitives 28a-28j is designed to be smaller than the lens width 18 of the microlenses 11 arranged in the micro-optical structure 03. To enhance contrast, it is now configured that at least on a portion of the associated printed image 27, on its side facing away from the micro-optical structure 03, a layer 39 extending in a planar shape and covering the associated printed image 27 is arranged, this layer 39 being composed of a hue lighter than at least one hue different from white constituting the associated printed image 27. As previously mentioned, layer 39 covering the relevant printed pattern 27 can be designed to be opaque to electromagnetic radiation with wavelengths in the range of 380 nm to 780 nm, or layer 39 can be transparent to electromagnetic radiation with wavelengths in the range of 380 nm to 780 nm, wherein the transparency to electromagnetic radiation is, for example, in the range of 10% to 90%. Furthermore, the transparency can be designed to gradually vary along the two-dimensional planar extension of layer 39 covering the relevant printed pattern 27, such that some locations of layer 39 are designed to have different transparency than other locations of layer 39. Therefore, specific elements 28a-28j of the relevant printed pattern 27 are emphasized for their improved legibility to the human eye, while other elements 28a-28j of the relevant printed pattern 27 are intentionally kept weaker in terms of their respective legibility. In a preferred embodiment, the layer 39 covering the associated printed pattern 27 is produced by inkjet printing, lithography, or screen printing, while the associated printed pattern 27 arranged on the opposite side of the substrate 26 to the micro-optical structure 03 is implemented by lithography.
[0061] By overprinting the printed image 27 applied to the back of the substrate 26 in the area of the transparent window 04, the contrast between the pixels and / or lines of the elements 28a-28j contained in the printed image 27 and their respective immediate surroundings is improved. Contrast is generally the difference in brightness between adjacent bright and dark areas in an image. By overprinting the printed image 27 applied to the back of the substrate 26 in the area of the transparent window 04 with a layer 39 made of light-colored, especially white ink, the contrast of the plurality, preferably most, especially all, elements 28a-28j in the related printed image 27 is increased when viewed through the micro-optical structure 03 from the direction of the convex envelope surface 13, so that the printed image 27, or at least the information contained therein, can be better discerned by the human eye even under low light, such as dim lighting conditions.
[0062] In a particularly advantageous embodiment of the invention, a layer 39 with enhanced contrast is obtained on the back side of the substrate 26, along with a security document 02 for a self-verifying mechanism, such as... Figure 6 The example is shown in the cross-sectional view and as described below.
[0063] Figure 6 Shown in Figure 5 The security document 02 illustrated in the example has a transparent window 04 constructed in its substrate 26, wherein a microlens structure 03 composed of microlenses 11 is arranged on one side of the substrate 26, at least in the area of the transparent window 04, and a first printed pattern 27 is arranged on the opposite side of the substrate 26 opposite to the microlens structure 03. Also in this embodiment, the first printed pattern 27 has a plurality of pixels 28a-28j in a dotted or linear grid pattern, which pixels 28a-28j are preferably formed in a tone different from white. The pixel size 38 or line thickness 38 of these pixels 28a-28j are respectively designed to be smaller than the lens width 18 of the microlenses 11 arranged in the micro-optical structure 03. For contrast enhancement, a layer 39 is arranged in a planar manner covering the surface of the first printed image 27, at least in a portion or segment of the first printed image 27 on the side facing away from the micro-optical structure 03. This layer 39 is preferably composed of a hue that is lighter than at least one hue different from white that constitutes the first printed image 27.
[0064] Now according to Figure 6 The proposed security document 02 and Figure 5The embodiment shown differs in that a second, preferably also offset-printed, pattern 41 is arranged on the side of layer 39 that partially covers the first printed pattern 27, opposite to the micro-optical structure 03. This second printed pattern 41 is arranged on layer 39 covering a portion of the first printed pattern 27 in such a way that the second printed pattern 41, when performing… Figure 6 Following the fold indicated by the arrow at the preferred fold line 07 that runs through security document 02, as in... Figure 4 As illustrated in the example, the micro-optical structures 03 applied to the other side of the substrate 26 of the security document 02 overlap, or at least are capable of overlapping, such that the second printed image 41, or at least one piece of information contained therein, is visible and / or identifiable when viewed from the direction of the micro-optical structures 03. The fold lines 07 folded on the substrate 26 of the security document 02 are preferably arranged outside the layer 39 that partially covers the first printed image 27, i.e., spaced apart from the layer 39. The fold lines 07 are preferably arranged in the portion of the first printed image 27 not covered by the layer 39 arranged on the first printed image 27.
[0065] According to the present invention Figure 6 In one embodiment, the elements 28a-28j of the first printed image 27 may be formed in a hue different from white, wherein the layer 39 that partially covers the first printed image 27 is composed of a hue that is lighter than at least one hue different from white that constitutes the first printed image 27.
[0066] Furthermore, the present invention is based on Figure 6 The implementation methods have at least some of the components already combined in each technically reasonable combination. Figure 1 and Figure 5 The features described.
[0067] Reference Figure 7 Now, let's explain: how can we, in particular, based on... Figure 5 or Figure 6The illustrated embodiment is used to manufacture security document 02. As already mentioned, the layer 39 covering the associated printed image 27, particularly for enhancing contrast, can also be produced by lithography or screen printing, although in the preferred embodiment this layer is produced by inkjet printing, while the associated printed image 27 arranged on the opposite side of the substrate 26 to the micro-optical structure 03 is produced by lithography. Here, the printed image 27 consists of a plurality of primitives 28a-28j printed with at least two different printing inks, these primitives 28a-28j themselves constituting pixels and / or lines. The pixel size 38 or line thickness 38 is preferably in the range of less than 20 μm, for example in the range of about 5 μm to 10 μm. The color registration accuracy of the primitives 28a-28j printed with different printing inks, i.e., the accuracy of their relative arrangement to each other, is less than 20 μm, preferably less than 10 μm, and particularly in the range of about 5 μm, in the embodiment considered here.
[0068] The manufacture of the printed image 27 with the aforementioned color registration accuracy is carried out, for example, in a printing press designed as a rotary printing press, particularly in a printing press used for printing securities, wherein a substrate 26, designed as a printing material web or a sheet of paper, is guided via a cylinder, for example, designed as a pressure cylinder 42, wherein printing ink relating to the associated printed image 27 is applied to the substrate 26 by continuous overprinting, or, in a preferred embodiment, the printing ink relating to the associated printed image 27 is collected, for example, on a transfer cylinder 43 and output together from the transfer cylinder 43 to the substrate 26 guided by the pressure cylinder 42. The substrate 26 is, for example, designed as a printing material web in the form of a polymer film or a sheet of paper.
[0069] At least two plate cylinders 44 are abutted or at least can abutted against the circumference of the transfer cylinder 43, each of these plate cylinders 44 transferring one of the printing inks involved in printing Figure 27 onto the transfer cylinder 43. The respective rotation directions of the pressure cylinder 42, the transfer cylinder 43, and the plate cylinder 44 are as follows: Figure 7 The directions of rotation are indicated by arrows. As is known to those skilled in the art, each printing cylinder 44 is equipped with... Figure 7 The inking unit is not shown. In a preferred embodiment, the printing inks delivered by the plate cylinder 44, which is attached to the transfer cylinder 43, are different in color.
[0070] Downstream of the transfer section (where the transfer roller 43 prints the ink collected thereon onto the substrate 26 guided by the pressure roller 42 to produce a printed image 27), a printing device is arranged on the same side of the substrate 26 as the printed image 27 produced on the transfer section, wherein the printing device at least partially overlays the printed image 27 with a layer 39 made of light-colored, preferably white, ink. This printing device is preferably designed as at least one inkjet printhead 46. In a preferred embodiment, the ink printed by the associated inkjet printhead 46 is lighter in tone than the corresponding tone of the ink applied to the substrate 26 by the transfer roller 43.
[0071] Preferably, an impression device 47 is also provided in the printing press, which forms a micro-optical structure 03 composed of microlenses 11 on the substrate 26. Thus, the impression device 47 can be arranged upstream of the pressure roller 42 in the printing press. However, in a particularly advantageous embodiment, the pressure roller 42 has the impression device 47 on its circumference, wherein the micro-optical structure 03 composed of microlenses 11 is formed by the impression device 47, and during rotation, the pressure roller 42 is arranged on the substrate 26 guided by the pressure roller 42. For example, the microlenses 11, made of synthetic materials or resin, have a lens width 18, for example, less than 100 μm, preferably between 20 μm and 65 μm.
[0072] Thus, a printing press for manufacturing security document 02 is obtained, wherein a pressure roller 42 is provided to guide the substrate 26 of security document 02, and a transfer roller 43, which cooperates with the pressure roller 42 at the transfer section, to print a printed image 27 onto the substrate 26. The substrate 26 of security document 02 has at least one transparent window 04, wherein a micro-optical structure 03 composed of microlenses 11 is provided on one side of the substrate 26, at least in the area of the relevant transparent window 04. The pressure roller 42 and the transfer roller 43 are arranged in such a way that, during the printing process, the micro-optical structure 03 composed of microlenses 11 is arranged on one side of the substrate 26, at least in the area of the relevant transparent window 04, and at least one printed image 27 is arranged on the opposite side of the substrate 26, at least in the area of the relevant transparent window 04. The arrangement of the micro-optical structure 03 made of microlens 11, implemented by the imprinting device 47, and at least one printed image 27 generated by the pressure roller 42 and the transfer roller 43 in the area of the transparent window 04, can be implemented simultaneously at the aforementioned transfer position or at different positions and staggered in time in relation to the circumference of the pressure roller 42.
[0073] The printing press also includes a printing device that applies a planar layer 39 covering the relevant printed image 27 on at least one segment of the image, on the side facing away from the micro-optical structure 03. This printing device is arranged downstream of a transfer section, where a transfer roller 43 prints the printed image 27 onto a substrate 26 guided by a pressure roller 42. The printing device is arranged on the same side of the substrate 26 as the printed image 27 implemented at the transfer section and is designed according to the invention as at least one inkjet printhead 46. In its preferred configuration, the relevant printed image 27 has a plurality of different shades of pixels 28a-28j arranged in a dotted or linear grid, wherein these pixels 28a-28j are each composed of a shade different from white, and the layer 39 formed by the at least one inkjet printhead 46 is composed of a shade lighter than the different white shade constituting the relevant printed image 27.
[0074] Advantageously, to maintain high registration accuracy, the pressure roller 42 has an imprinting device 47 on its circumference, wherein the imprinting device 47 forms a micro-optical structure 03 composed of microlenses 11 and is arranged such that the imprinting device constructs the micro-optical structure 03 composed of microlenses 11 on the substrate 26 guided by the pressure roller 42 during the rotation of the pressure roller 42, that is, during the ongoing printing process. The pixel size 38 or line thickness 38 of the elements 28a-28j of the associated printed figures 27 is preferably smaller than the lens width 18 of the microlenses 11 arranged in the micro-optical structure 03.
[0075] In a preferred design of the printing press, at least two plate cylinders 44 are provided that abut or are able to abut on the circumference of the transfer cylinder 43. Each of these plate cylinders 44 transfers one of the printing inks relating to the relevant printed image 27 to the transfer cylinder 43, wherein the transfer cylinder 43 collects these different colored printing inks and transfers the printing inks collected on the transfer cylinder 43 together onto the substrate 26 guided by the pressure cylinder 42.
[0076] List of reference numerals
[0077] 01 Security Elements
[0078] 02 Security Documents
[0079] 03 Optical imaging structures; micro-optical structures
[0080] 04 Window
[0081] 05-06 Notch
[0082] 07 Broken line 08 -09 -10 -11 Microlens
[0083] 12. Axis of symmetry; optical axis
[0084] 13. Convex envelope surface
[0085] 14 Beams 15-16 Edge Points
[0086] 17 Edge Points
[0087] 18 Lens width
[0088] 19 Principal plane 20-21 Flat envelope
[0089] 22 focal length
[0090] 23 Focus
[0091] 24 Focal plane 25-26 Substrate
[0092] 27 Printing Figure 28 Element (28a-28j)
[0093] 29. Material thickness; Thickness 30-31. Cutting plane
[0094] 32. Cone; Corner Field
[0095] 33 First viewing angle; 34 Second viewing angle; 35-36 Layer thickness
[0096] 37 Vertex; 38 Pixel Size; 39 Line Thickness; 40-41 Printing Image
[0097] 42 Pressing Rollers
[0098] 43 Transfer cylinder 44 Plate cylinder 45-46 Inkjet printhead 47 Imprinting unit
Claims
1. A printing press for producing security documents (02), wherein, An impression cylinder (42) is provided on a substrate (26) containing a security document (02), and a transfer cylinder (43) is provided on the substrate (26) in conjunction with the impression cylinder (42) at the transfer position to print a printed image (27) onto the substrate (26). The substrate (26) of the security document (02) has at least one transparent window (04), and a micro-optical structure (03) composed of microlenses (11) is provided on one side of the substrate (26) at least in the area of the corresponding transparent window (04). The impression cylinder (42) and the transfer cylinder (43) are arranged in such a way that a micro-optical structure (03) composed of microlenses (11) is provided on one side of the substrate (26) at least in the area of the corresponding transparent window (04). The micro-optical structure (03) is composed of a lens (11), and on the opposite side of the substrate (26) from the micro-optical structure (03), at least one printed pattern (27) is arranged in the area of the corresponding transparent window (04), wherein the corresponding printed pattern (27) has multiple elements (28a-28j) in a dotted or line grid, wherein these elements (28a-28j) of the printed pattern (27) are designed with a color tone different from white, wherein a layer (39) extending in a planar shape and covering the corresponding printed pattern (27) is provided on at least a portion of the corresponding printed pattern (27) on the side of the corresponding printed pattern opposite to the micro-optical structure (03). A printing apparatus for printing ink, wherein the printing apparatus is arranged downstream of the transfer portion on the substrate (26) guided by the impression cylinder (42) where the transfer cylinder (43) prints a printout (27) onto the transfer portion, and is located on the same side of the substrate (26) as the printout (27) produced on the transfer portion, and the printing apparatus is designed such that the layer (39) formed by the printing apparatus is composed of a shade lighter than the white hue constituting the corresponding printout (27), characterized in that the printing apparatus arranged downstream of the transfer portion on the transfer cylinder (43) where the transfer cylinder (43) prints the printout (27) onto the substrate (26) guided by the impression cylinder (42) is designed as at least one inkjet printhead (46). The at least one inkjet printhead (46) is designed such that the layer (39) formed by the inkjet printhead is formed of white ink, wherein the impression cylinder (42) has an impression mechanism (47) on its circumference, wherein the impression mechanism (47) forms a micro-optical structure (03) composed of microlenses (11), and the impression mechanism is arranged such that the impression mechanism forms the micro-optical structure (03) composed of microlenses (11) on a substrate (26) guided by the impression cylinder (42) during the rotation of the impression cylinder (42), wherein the impression mechanism (47) is designed to form the microlenses (11) using a die-casting method.
2. The printing press according to claim 1, characterized in that, The corresponding printed image (27) has primitives (28a-28j) consisting of at least two different hues, wherein the layer (39) formed by the at least one inkjet printhead (46) consists of a hue that is lighter than each hue constituting the corresponding printed image (27).
3. The printing press according to claim 1 or 2, characterized in that, The pixel size (38) or line thickness (38) of the corresponding printed pattern (27) elements (28a-28j) is designed to be smaller than the lens width (18) of the microlens (11) arranged in the micro-optical structure (03).
4. The printing press according to claim 1 or 2, characterized in that, At least two printing plate cylinders (44) are provided on the circumference of the transfer cylinder (43), wherein each of the printing plate cylinders (44) transfers the printing ink constituting the corresponding printed image (27) to the transfer cylinder (43), wherein the transfer cylinder (43) collects these different shades of printing ink and is designed such that the printing ink collected on the transfer cylinder (43) is transferred together to the substrate (26) guided by the impression cylinder (42).
5. The printing press according to claim 1 or 2, characterized in that, The printing mechanism (47) and the transfer roller (43) that cooperates with the printing roller (42) at the transfer position to print the printed image (27) onto the substrate (26) are arranged in the printing press in such a way that the arrangement of the micro-optical structure (03) composed of microlenses (11) and the arrangement of at least one printed image (27) to be arranged in the area of the transparent window (04) are carried out simultaneously.
6. The printing press according to claim 1 or 2, characterized in that, The printing mechanism (47) and the transfer roller (43) that cooperates with the printing roller (42) at the transfer position to print the printed image (27) onto the substrate (26) are arranged in the printing press in such a way that the arrangement of the micro-optical structure (03) composed of microlenses (11) and the arrangement of at least one printed image (27) to be arranged in the area of the transparent window (04) are staggered in time.
7. The printing press according to claim 1 or 2, characterized in that, The imprinting mechanism (47) is designed such that it forms a microlens (11) made of synthetic material.
8. The printing press according to claim 1 or 2, characterized in that, The embossing mechanism (47) is designed such that it forms a microlens (11) made of resin.
9. The printing press according to claim 1 or 2, characterized in that, The substrate (26) is designed as a web of printing material or a sheet of printing material.
10. The printing press according to claim 1 or 2, characterized in that, The substrate (26) is designed to be a polymer film or made of paper.
11. The printing press according to claim 1 or 2, characterized in that, The printing press is designed as a rotary printing press for printing securities.
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