DE102005008135A1 - Disk with halftone image - Google Patents

Abstract

The invention relates to a data support (20) with a continuous tone image produced by gravure printing, comprising printed part surfaces (26, 28) with defined tone values, whereby at least three printed part surfaces have differing tone values. According to the invention, one or more of the different tone values for the printed partial surfaces (28) which appears fully printed to the naked eye is formed with a certain proportion of non-printed white regions (W).

Description

The The invention relates to a data carrier with a half-tone image produced in intaglio printing, the printed subareas having certain tonal values, with at least three printed ones subareas have different tonal values. The invention further relates a gravure printing plate and a gravure printing method for printing Halftone images with three or more different tonal values as well a method for producing such a gravure printing plate.

Data carrier in the sense The present invention relates, in particular, to security or value documents. like banknotes, passports, Identity documents, check forms, shares, certificates, stamps, vouchers, Air tickets and the like, as well as labels, seals, packaging and other elements for the product assurance. The term "data carrier" in the following includes all such Documents and product safety devices.

safety and value documents, their commercial value or value in use, the material value far exceeds are usually identified by appropriate action as genuine and imitations and counterfeits made distinguishable. They are usually with special security elements provided that ideally not or only with great effort imitable and not fake are.

In In the past, especially those security elements have become proven, the viewer identified without aids and recognized as genuine can be but at the same time only with high technical or economic Effort can be made. These are, for example, watermarks that are only during the Paper production in the disk can be introduced or printed images produced by intaglio printing, which are through one too for the Laypersons recognize easily recognizable characteristic tactility, which can be obtained by other printing methods and in particular by copying machines or Scanner not reproduced.

The Line or intaglio printing technique, in particular the steel intaglio technique, has for the printing of data carriers, in particular of securities, such as banknotes and the like, a great importance. The intaglio printing is characterized by the fact that in the printing plates linear depressions are introduced to create a printed image. The color-transmitting Areas of the printing plate are thus present as depressions in the printing plate surface. These depressions are by means of a suitable engraving tool or by means of etching generated. In the case of the mechanically produced printing plate for intaglio printing is due to the usual tapered engraving tools with increasing stitch depth creates a wider line. Furthermore takes the ink receptivity the engraved line and thus the opacity of the printed line with increasing stitch depth too.

at the etching of intaglio printing plates are the non-printing areas of the Pressure plate covered with a chemically inert paint. By subsequent etching is in the exposed plate surface generates the engraving, wherein the depth of the engraving lines depends in particular on the etching time.

In front the actual printing process is on the engraved printing plate Color pasty Consistency applied and the excess ink by means of a doctor blade or a wiping cylinder from the surface of the Pressure plate removed, leaving the paint only in the wells remains. Subsequently, will a substrate, usually paper, against the printing plate and in the process also in the color filled Recesses of the pressure plate pressed and withdrawn, where the paint is pulled out of the depressions of the printing plate, at the substrate surface sticks and forms a printed image there. Be transparent colors used, the thickness of the paint application determines the hue. How to get at Printing on a white disk with light color layer thicknesses a light tint, when printing with thick ones Color layers darker shades. The ink layer thickness is in turn dependent to some extent on the engraving depth.

The Line intaglio printing technique leaves compared to other common ones Printing techniques, such as offset printing, a relatively thick Paint application on a data carrier to. The line-inprinting method generated comparatively thick paint layer is together with the partial deformation of the Paper surface, by pressing the paper into the engraving of the printing plate comes about, also for The layman can feel it easily and manually as well as their tactility easily recognizable as an authenticity feature. The tactility is with a copier not imitate, so the line intaglio printing a high quality protection against counterfeiting offers.

However, conventional line intaglio printing methods have the disadvantage that tactility and simultaneously full-surface printing can not be realized in one print run in the print image. As a remedy, it has been proposed in document WO 03/052702 A2 to provide a data carrier with an im Intaglio printing provided half-tone image comprising at least a portion of the image directly adjacent printed partial areas, wherein the partial surfaces have certain tonal values and at least a portion of the image is tactile perceptible. As used herein, the term "halftone image" refers to an image that has intermediate tones between the brightest and darkest image locations, and where "black level" is a "black level" image, as is conventional, a value to understand on a gray scale from white to black. However, the present invention relates not only to black and white halftone images containing the achromatic colors, namely, white, black and gray, but also to monochrome or multicolor halftone images comprising the so-called bright colors. In the case of the colorful halftone images, the term "tone value" is understood to mean the brightness of the color under consideration.

to Production of such a printed image is described in WO 03/052702 A2 a template, such as a portrait, divided into halftone-related sub-areas and the individual tone values or groups of tone values on the used printing ink, different engraving depths for the assigned to be produced pressure plate. The tonal values of the template be implemented in corresponding engraving depths on the printing plate, wherein the for the generation of a special tone value necessary engraving depth can vary from ink to ink.

outgoing It is the object of the invention to provide a data carrier with increased counterfeit security to create, which is a half-tone picture produced in the intaglio printing with a large number from available having standing halftone values.

These Task is through the disk with the features of the main claim. A gravure printing process and a gravure printing plate for producing a data carrier according to the invention, and a method for producing such a gravure printing plate are given in the independent claims. further developments The invention are the subject of the dependent claims.

According to the invention are with a disk of the type mentioned one or more of the different Tonal values for the mere Eye over the entire surface appearing printed areas formed with a certain proportion of unprinted white areas. By the Use of such white areas can be the number of available halftone values significantly increased and at the same time a targeted halftone control can be achieved.

For example can when using three different engraving depths through the use of different greater White shares Eight different tonal values can be easily realized that already have one extraordinarily realistic representation of halftone images, such as portraits, allow. Furthermore It has been found that the use of the white areas according to the invention leads to a stabilization of the color of the printed faces, what especially when using poorly translucent printing inks makes beneficial noticeable.

In A preferred embodiment provides that the unprinted White areas at least one of the different tonal values by a crowd parallel white lines are formed. Alternatively or additionally, according to a another, likewise preferred embodiment, the unprinted White areas at least one of the different tonal values through a regular cross grid educated. The white areas arise, for example, by the intersecting between two Flocks of parallel printing lines remaining diamond-shaped spaces.

According to one Another advantageous embodiment of the invention form the unprinted white areas at least one of the different tonal values a hidden information, like a pattern or a string. By such, with naked Eye not recognizable Additional information in the fine structure of the printed image can the counterfeit security of the disk further increased become. The information of the white areas can be present as positive or negative information. she may also be provided only in a portion of the halftone image.

With Advantage is at least one of the printed faces of the Halftone image tactilely perceptible or contains a tactile perceptible Structural element and thereby forms an effective protection against Imitation, e.g. by copying.

The Expansion of the unprinted white areas is in at least a dimension smaller than 100 μm, preferably less than 80 μm, more preferably less than 60 microns, even more preferably smaller than 40 μm and more preferably less than 20 microns. To meet this condition, the white areas For example, lines with a width smaller than 100 microns (or smaller as 80 μm or 60 μm or 40 μm or 20 μm) or through areas of any kind Shape with a surface area smaller than 100 μm × 100 μm (or smaller as 80 μm × 80 μm or 60 μm × 60 μm or 40 μm × 40 μm or 20 μm × 20 μm) be.

In a preferred embodiment At least six, for example eight, printed partial areas have different tonal values which are each formed by printed partial areas which appear to be full-surface to the naked eye and have a certain proportion of unprinted white areas. With such a fine resolution of the tonal values, almost photorealistic-looking representations can be achieved in intaglio printing.

The subareas of the halftone image derived in particular from a halftone image template superimposed grid be as described in international application WO 03/052702. Also, the halftone image as described in WO 03/052702, additional Have tactile structural elements, or at least in some areas superimposed with fine structures be that affect its visual appearance and in individual subareas have a different orientation. WO 03/052702 describes also different possibilities for converting a halftone original into a gravure printing image, the can also be used in the present invention. Regarding the mentioned objects is the disclosure of WO 03/052702 by reference in the present Registration received.

The Invention contains Further, a gravure printing plate for printing a halftone image with at least three different engraved areas in the Printing plate surface, which serve to print different tonal values. One or more of at least three engraved areas have a specific one Proportion of non-printing white areas on top of that through the printing plate surface lying surfaces are formed and their extent at least in one dimension below the resolution limit of the bare one Eye is lying.

With Advantage can the non-printing white areas at least one of the engraved areas of such a printing plate from a family of parallel engraving lines whose distance is greater than the line width of the engraving lines is. Under distance is not to understand the non-printing space between the engraving lines, but the distance e.g. from the left flank of an engraving line to the left flank of the next Engraved line. Alternatively or in addition can the non-printing white areas at least one of the engraved areas also consists of two sub an angle crossing groups of parallel engraving lines result. The distance of the engraving lines within each flock is bigger here as well the line width of the engraving lines, so that diamond-shaped white areas result. The two hosts cross each other favorably under one Angle between 40 ° and 80 °, preferably between 50 ° and 70 °, for example is about 60 °.

The Engraving lines of the intaglio printing plate or the printed lines preferably have a width below 60 microns, more preferably below 50 μm, in particular preferably below 30 microns on.

According to one Development of the invention form the non-printing white areas at least one of the engraved areas has hidden information, such as a pattern or a string to the counterfeit security of the generated Halftone images continue to increase. The hidden information can be positive or negative Information is available and only in a partial area of the halftone image be provided.

Preferably sit down in the amount the printing plate surface lying surfaces the white areas with a flank angle α in the depth of the pressure plate continues, between 15 ° and 60 °, preferably between 30 ° and 50 °, respectively based on the surface normal the pressure plate, lies. At least one of the engraved areas advantageously has a base area with a basic roughness pattern, such as for example the method described in the document WO 97/48555 can be.

• – Bereitstellen einer Druckplatte mit einer Druckplattenoberfläche,
• – Gravieren von wenigstens drei unterschiedlichen Bereichen in die Druckplatte, wobei in einem oder mehreren der drei Bereiche ein bestimmter Anteil nichtdruckender Weißbereiche stehen gelassen wird, welche durch in Höhe der Druckplattenoberfläche liegende Flächen gebildet werden, deren Ausdehnung zumindest in einer Dimension unterhalb der Auflösungsgrenze des bloßen Auges liegt.

The invention also includes a method for producing a gravure printing plate for printing a halftone image having three or more different tone values, comprising the steps of:

• Providing a printing plate with a printing plate surface,
• Engraving at least three different areas in the printing plate, leaving in one or more of the three areas a certain proportion of non-printing white areas formed by surfaces lying at the level of the printing plate surface, the extent of which is at least one dimension below the resolution limit of the bare area Eye is lying.

The in height the printing plate surface lying surfaces the white areas are advantageously designed so that they are with a Flank angle α in extend the depth of the pressure plate, between 15 ° and 60 °, preferably between 30 ° and 50 °, based on the surface normal of the Pressure plate, lies. For engraving is appropriate Engraving tool used with a corresponding flank angle α.

The intaglio printing plates according to the invention are preferably produced by engraving with a stylus, particularly preferably with a rapidly rotating, conically tapering stylus, as described in the document WO 97/48555. As a result, in particular colorful, so example monochrome blue or red halftone images are generated with bright, intense hues that show no signs of gray or brown blending in the various tone gradations. In principle, however, the engravings can also be produced by means of laser engraving or etching or any other suitable removal method.

By the use of intaglio printing technology, in particular the Stahlstichtiefdrucktechnik for the halftone images according to the invention becomes a characteristic, easily recognizable also for laymen Print and embossed image achieved with other common printing methods can not be readjusted. The intaglio printing technique and the Therefore, innovations disclosed herein are particularly valuable for printing or security-related data carriers, such as security or security Value documents suitable, the high requirements in terms of counterfeit protection have to do justice.

Further embodiments as well as advantages of the invention are described below with reference to FIGS explains in their representation on a scale and proportion Play has been omitted in order to increase the clarity.

It demonstrate:

1 1 is a schematic representation of a banknote with a half-tone image produced in intaglio printing according to an embodiment of the invention,

2 a section of the banknote 1 in the area of the halftone image in cross section,

3 a corresponding section of the profile of the production of the halftone image of 2 used intaglio printing plate, also according to an embodiment of the invention, and

4 in (a) to (e) various views on printed according to the invention partial areas of a data carrier when viewed with a magnifying glass or a microscope.

The invention will now be explained using the example of a banknote. 1 shows a banknote 10 , which with a halftone image produced by intaglio printing 12 is provided, which is shown schematically in the figure as a black and white portrait. Typically, the entire printed image of the banknote consists of a superposition of a plurality of printed images, which are produced with different printing methods. Beside or instead of the portrait 12 can also be another graphic motif 14 be executed as intaglio halftone image according to the invention. In the latter case, the portrait 12 also be produced with conventional intaglio printing.

In addition, the banknote 10 a pattern produced in offset printing 16 For example, a guilloche pattern of regularly interlaced lines or other finely structured pattern, as well as a serial number printed in letterpress printing 18 , It is also possible to provide areas created by screen printing or by further printing processes.

2 shows for illustration a section of the banknote 10 in the area of intaglio halftone image 12 in cross section. The section shown shows the deformed during the printing process by the contact pressure banknote paper 20 , which recesses on the banknote back 22 and on the banknotes front elevations 24 having. In the printed partial areas 26 and 28 , of which only a part is shown in the figure, are the surveys 24 each with color layers 36 respectively. 38 covered when printing from the engraved areas 46 and 48 ( 3 ) of the printing plate 40 were recorded.

The first printed part 26 is with a color layer 36 a certain color layer thickness D covered and appears within the halftone image 12 in a first tone value determined by the nature of the printing ink and banknote paper used.

The second printed part 28 is with a color layer 38 covered, the same thickness D as the color layer 36 the first partial area 26 having. In contrast to the first partial area, the printed image is the second partial area 28 However, formed with a certain proportion of unprinted white areas W. The extent of the white areas W is at least in one dimension below the resolution limit of the naked eye, so that they can not be resolved without aids.

The second printed part 28 therefore appears to the naked eye as a uniform, fully printed surface. However, due to the presence of white, it appears within the halftone image 12 despite the same color layer thickness D in a second tone that is lighter than the first tone of the patch 26 is.

In this way, with the aid of a constant ink layer thickness, it is possible in each case to set several different tonal values by means of the white component, the brightness of which is in each case up to the brightness of the continuous ink layer 36 the first partial area 26 pass. By a combination of different color layer thicknesses D and different white Thus, a multiplicity of tonal values can be obtained between "white" and "black" (or the completely covering characteristic of the printing ink used). It is understood that in a halftone image, there does not necessarily have to be a tone value that is due to a full-surface color layer 36 is pictured. Rather, it may be advantageous to represent all occurring tonal values by partial areas with a certain amount of white.

3 shows the representation of the 2 corresponding section of the profile of the associated intaglio printing plate 40 , In the printing plate surface 42 are a first engraving area 46 and a second engraving area 48 each engraved with the same engraving depth T. During the first engraving area 46 is formed throughout and thus during the printing process to a continuous color layer 36 leads, is the second engraving area 48 with up to the printing plate surface 42 reaching bridges 50 equipped, whose at the level of the printing plate surface 42 lying surfaces 52 form non-printing white areas.

The bridges 50 sit down on the surface 42 the pressure plate lying surfaces 52 with a flank angle α in the depth of the pressure plate, which is given essentially by the engraving tool used. In the exemplary embodiment, the engraving areas of the intaglio printing plate 40 Engraved with a rotating stylus whose flank angle to be generated flank angle of the webs 50 equivalent.

In order to produce different white areas or different white parts at the same engraving depth, the engraving tool can be guided along different paths for the different partial areas. 4 shows in (a) to (e) some exemplary embodiments. Shown in each case is a plan view of a uniformly printed partial area of a data carrier, as it shows when viewed with a magnifying glass or a microscope.

4 (a) shows a first section 60 in which the associated intaglio printing plate contains a family of parallel engraving lines whose spacing is greater than the line width of the engraving lines. In the exemplary embodiment, for example, at an engraving depth of 15 .mu.m, approximately 30 .mu.m wide engraving lines were produced with a spacing of 60 .mu.m. In the printed image, this results in a relatively bright partial area appearing to the naked eye over the entire surface, which under the magnifying glass or a microscope is exactly the same as in 4 (a) shown structure from a line of parallel printing lines 62 and intermediate parallel white lines 64 shows.

The use of cross gratings, as they result from two sets of parallel engraving lines crossing at a certain angle β, also leads to very good results. As in the clipping 70 of the 4 (b) shown, the intersecting lines of lines produce 72 in the printed image small, diamond-shaped white areas 74 , On the associated intaglio printing plate small, up to the printing plate surface reaching truncated pyramids are left by the intersecting engraving lines whose non-printing top surfaces in intaglio printing just the diamond-shaped white areas shown 74 result.

The engraving lines of the printing plate do not necessarily have to be rectilinear, as in the in 4 (c) shown detail 80 illustrates the two intersecting, curved lines of lines 82 and white areas included 84 shows.

The white areas may also represent hidden information, such as a pattern or a string, which is recognizable only when magnified accordingly. Merely by way of example, the sections show 90 respectively. 94 of the 4 (d) and (e) simple variants of such designs in which the white areas in the form of the letter "D" are positive information (reference numerals) 92 . 4 (d) ) or negative information (reference numeral 96 . 4 (e) ). Different tonal values can also be set here by the line width of the engraving lines and / or the spacing of the individual information elements (in this case the letter "D"). Of course, even more complex information can be introduced into the printed image in this way.

Claims (29)

Data carrier with a halftone image produced by intaglio printing, having printed sub-areas with specific tonal values, wherein at least three printed subareas have different tonal values, characterized in that one or more of the different tonal values are printed areas with a certain proportion of unprinted white areas appearing to the naked eye are formed. disk according to claim 1, characterized in that the unprinted White areas at least one of the different tonal values by a crowd parallel white lines are formed. disk according to claim 1 or 2, characterized in that the unprinted White areas at least one of the different tonal values through a regular cross grid are formed. disk according to at least one of the claims 1 to 3, characterized in that the unprinted white areas at least one of the different tonal values a hidden information, how to form a pattern or a string. disk according to at least one of the claims 1 to 4, characterized in that the at least one of the printed subareas of the halftone image is tactile perceptible. disk according to at least one of the claims 1 to 5, characterized in that the extension of the unprinted White areas in at least one dimension smaller than 100 μm, preferably smaller than 80 μm, especially preferably less than 60 microns is. disk according to at least one of the claims 1 to 6, characterized in that at least six printed subareas have different tonal values, each by the naked eye entire area appearing printed areas are formed with a certain proportion of unprinted white areas. disk according to at least one of the claims 1 to 7, characterized in that the halftone image is a portrait represents. Intaglio printing plate for printing a halftone image with at least three different engraved areas in the Printing plate surface for printing different tonal values, characterized that one or more of the at least three engraved areas have a certain proportion of non-printing white areas, which through in height the printing plate surface lying surfaces are formed whose extent at least in one dimension below the resolution limit of the bare one Eye is lying. Intaglio printing plate according to claim 9, characterized that the non-printing white areas at least one of the engraved areas is made up of a group of parallel Engraving lines whose distance is greater than the line width of the engraving lines is. Intaglio printing plate according to claim 9 or 10, characterized characterized in that the non-printing white areas at least one of engraved areas are made up of two, intersecting at an angle Scales each parallel engraving lines result, the distance each greater than the line width of the engraving lines is. Intaglio printing plate according to claim 11, characterized in that that the two coulters at an angle between 40 ° and 80 °, preferably between 50 ° and Cross 70 °. Intaglio printing plate according to at least one of claims 10 to 12, characterized in that the engraving lines have a width below of 60 μm, preferably below 50 microns exhibit. Intaglio printing plate according to at least one of claims 9 to 13, characterized in that the non-printing white areas at least one of the engraved areas has hidden information, how to form a pattern or a string. Intaglio printing plate according to at least one of claims 9 to 14, characterized in that lying in height of the printing plate surface surfaces the white areas with a flank angle α in Continue the depth of the printing plate between 15 ° and 60 °, preferably between 30 ° and 50 °, based on the surface normal of the Pressure plate, lies. Intaglio printing plate according to at least one of claims 9 to 15, characterized in that at least one of the engraved Areas a base area having a roughness basic pattern. Intaglio printing plate according to at least one of claims 9 to 16, characterized in that at least six different engraved areas intended for printing different tonal values each having a certain proportion of non-printing white areas which are characterized by in height the printing plate surface lying surfaces are formed whose extent at least in one dimension below the resolution limit of the naked Eye is lying. Intaglio printing process for printing a halftone image with three or more different tonal values, in which a gravure printing plate according to one of the claims 9 to 17 is used. Method for producing a gravure printing plate for printing a halftone image with three or more different ones Tone values, with the process steps: - Providing a printing plate with a printing plate surface, - Engraving at least three different areas in the pressure plate, wherein in one or more of the three areas a certain proportion of non-printing White areas is left, which by lying at the level of the printing plate surface Surfaces formed whose extent is at least one dimension below the resolution limit of the bare one Eye is lying. A method according to claim 19, characterized ge indicates that the non-printing white areas of at least one of the engraved areas are generated from a family of parallel engraving lines whose spacing is greater than the line width of the engraving lines. Method according to claim 19 or 20, characterized that the non-printing white areas at least one of the engraved areas of two is under one Angle-crossing crowds each generated parallel engraving lines whose distance is greater than the line width of the engraving lines is. Method according to claim 21, characterized that the two flocks at an angle between 40 ° and 80 °, preferably between 50 ° and Cross 70 °. Method according to at least one of claims 20 to 22, characterized in that the engraving lines with a width below 60 microns, preferably below 50 microns be generated. Method according to at least one of claims 19 to 23, characterized in that the non-printing white areas at least one of the engraved areas in the form of a hidden Information about how to create a pattern or a string. Method according to at least one of claims 19 to 24, characterized in that lying in height of the printing plate surface surfaces the white areas with a flank angle α in the depth of the printing plate continues to be generated, the between 15 ° and 60 °, preferably between 30 ° and 50 °, based on the surface normal the pressure plate, lies. Method according to claim 25, characterized in that that used for engraving a engraving tool with a corresponding flank angle α becomes. Method according to at least one of claims 19 to 26, characterized in that for engraving a rotating stylus is used. Method according to at least one of claims 19 to 26, characterized in that the engraving by means of laser beam or by etching. Method according to at least one of claims 19 to 28, characterized in that in at least one of the engraved Areas a base area is generated with a roughness basic pattern.