Method for engraving an intaglio plate, intaglio plate and printing method

Description

[0001] The invention relates to a method for engraving an intaglio intaglio printing plate according to the preamble of patent claim 1.

[0002] Methods for producing an intaglio intaglio printing plate are known, whereby the intaglio intaglio printing plate is engraved directly using a laser or stylus. Engraving methods that use direct ablation using a laser are also referred to as Direct Laser Engraving (DLE). Here, the surface of the intaglio printing plate blank is scanned in several layers using a laser in order to ablate the surface layer by layer. This also allows complex three-dimensional depth profiles to be produced for intaglio printing. Here, several two-dimensional engraving layers are generated from a three-dimensional depth profile and are ablated one after the other. One such method is known, for example, from EP 2 119 527 A1.

[0003] DE 196 24 131 A1 discloses a method that enables the simple and automated production of embossing plates, particularly steel gravure printing plates. First, the edge of a target contour is removed, followed by the removal of a residual area within the target contour. Furthermore, during the removal of the residual area at the base of the engraving, the offset and shape of the engraving tool create a defined roughness structure, which can serve as an ink trap for an applied steel gravure printing ink.

[0004] From DE 198 45 440 A1, an intaglio printing process comprising separating strips that protrude vertically from the printing ink of the engraving areas is known.

[0005] EP 1 393 925 A1 also discloses a gravure printing plate for a rotary printing press.

[0006] DE 196 24 131 A1, DE 198 45 440 A1 and EP 1 393 925 A1 do not show the engraving of several engraving layers in descending order of depth, so that an engraving layer with a greater depth is engraved before an engraving layer with a lesser depth.

[0007] The disadvantage is that if the intaglio ink is applied to the intaglio intaglio plate and wiped off to remove excess ink, intaglio ink is also inadvertently removed from the three-dimensional depth profile. This results in a loss of quality in the printed result.

[0008] The object of the invention is therefore to provide a method of the type mentioned at the outset with which the disadvantages mentioned can be avoided and with which an intaglio intaglio printing plate for high-quality intaglio printing can be easily produced.

[0009] According to the invention, this is achieved by the features of patent claim 1.

[0010] This has the advantage that the micro-grooving better retains the intaglio ink during the wiping step in engraving sections that run in the wiping direction. From a topographical perspective, the micro-grooving prevents excessive ink removal from the intaglio plate, especially from larger, connected areas, such as a depression. This means that the ink application of lines along and across the wiping direction is more similar because less intaglio ink is wiped out from engraving sections or areas along the wiping direction. Due to the particularly extensive micro-grooving in the depth profile or above the engraving areas, no individual separating strips or other additional design elements need to be arranged to maintain the ink retention topography.By engraving the micro-grooving using essentially parallel lines with a predetermined first line spacing, good ink retention on the intaglio intaglio plate during the wiping step can be achieved easily and without additional design effort.

[0011] Furthermore, an intaglio intaglio printing plate with an ink retention topography formed as a micro-fluting is provided.

[0012] The object of the invention is therefore to provide an intaglio intaglio printing plate of the type mentioned at the outset, with which the disadvantages mentioned can be avoided and with which the quality of the intaglio printing can be improved.

[0013] According to the invention, this is achieved by the features of patent claim 6.

[0014] The advantages of the intaglio intaglio printing plate correspond to the advantages of the process.

[0015] A method for printing a security feature using the intaglio intaglio printing plate is also provided.

[0016] The object of the invention is therefore to provide a method of the type mentioned at the outset with which the disadvantages mentioned can be avoided and with which the quality of intaglio intaglio printing can be improved.

[0017] According to the invention, this is achieved by the features of patent claim 7.

[0018] The advantages of the procedure correspond to those mentioned above.

[0019] The subclaims relate to further advantageous embodiments of the invention.

[0020] Express reference is hereby made to the wording of the claims, whereby the claims are incorporated into the description at this point by reference and are deemed to be reproduced verbatim.

[0021] The invention will be described in more detail with reference to the accompanying drawings, in which only preferred embodiments are shown by way of example. In the drawings: Fig. 1 a schematic representation of a first preferred embodiment of an intaglio intaglio printing plate in side view; Fig. 2 a schematic representation of a depth profile with a micro-grooving according to a first preferred embodiment of an intaglio intaglio printing plate in side view; Fig. 3 a schematic representation of a second preferred embodiment of an intaglio intaglio printing plate in side view; Fig. 4 a schematic representation of a depth profile with two micro-grooves according to a second preferred embodiment of an intaglio intaglio printing plate in side view; Fig. 5 a schematic representation of a first laser engraving path in side view; Fig. 6 a schematic representation of a depth profile of a third preferred embodiment of an intaglio intaglio printing plate in side view; Fig. 7 a schematic representation of a second laser engraving path in side view; Fig. 8 a schematic representation of a depth profile of a fourth preferred embodiment of an intaglio intaglio printing plate in side view; Fig. 9 a preferred embodiment of a multitonal printed image in plan view; Fig. 10 a schematic representation of a depth profile of a fifth preferred embodiment of an intaglio intaglio printing plate with color pigments of different sizes in side view and Fig. 11 a schematic representation of a depth profile of a sixth preferred embodiment of an intaglio intaglio printing plate with dipolar and neutral color pigments.

[0022] The Fig. 1 bis 11 show at least parts of a preferred embodiment of an intaglio intaglio printing plate 1 with an ink retention topography formed as micro-grooving 9,10.

[0023] Furthermore, a method for engraving an intaglio intaglio printing plate 1 is provided, wherein a depth profile 2 of the intaglio intaglio printing plate 1 is produced by engraving at least one engraving layer 4, 5, 6, 7, wherein at least one region of the depth profile 2 of the intaglio intaglio printing plate 1 is provided with a micro-groove 9, 10 to produce an ink retention topography, wherein the micro-groove 9, 10 is produced by engraving essentially parallel lines with a predetermined first line spacing 11.

[0024] Furthermore, a method for printing a security feature with an intaglio intaglio printing plate 1 is provided, wherein in an ink application step an intaglio printing ink is applied to the intaglio intaglio printing plate 1, wherein in a wiping step excess intaglio printing ink is wiped off the intaglio intaglio printing plate 1 along a wiping direction and wherein in a printing step the intaglio printing ink is transferred from the intaglio intaglio printing plate 1 to the object to be printed.

[0025] This results in the advantage that, due to the micro-grooving 9, 10, the intaglio printing ink is better retained during the wiping step in engraving sections that run in the wiping direction. From a topographical perspective, the micro-grooving 9, 10 prevents excessive ink removal from, in particular, larger, connected areas, for example from a depression, of the intaglio intaglio printing plate 1 during wiping. Thus, the ink application of lines longitudinally and transversely to the wiping direction is more similar because less intaglio printing ink is wiped out from engraving sections or engraving areas along the wiping direction. Due to the particularly extensive micro-grooving 9, 10 in the depth profile or above the engraving areas, no individual separating bars or other additional design elements need to be arranged to maintain the ink retention topography.By engraving the micro-grooving 9, 10 by means of essentially parallel lines with a predetermined first line spacing 11, good ink retention on the intaglio intaglio printing plate 1 during the wiping step can be achieved easily and without additional design effort.

[0026] Intaglio printing is a printing process for printing with an engraved intaglio printing plate 1, whereby the form of the engraving is not only applied as ink to the sheets to be printed, but also results in a lasting and often palpable plastic deformation of the printed sheets, which is why intaglio printing is often used as a security feature for security documents such as banknotes, stamps or securities.

[0027] In particular, it can be provided that the intaglio intaglio printing plate 1 is used to produce a security document, since this allows security features of high quality to be reliably applied to the security document.

[0028] The finished engraved intaglio intaglio printing plate 1 has in particular a three-dimensional depth profile 2, which is applied in reverse to the sheets to be printed during the printing process.

[0029] In particular, it can be provided that a substantially flat intaglio intaglio printing plate 1 is engraved. Such flat intaglio intaglio printing plates 1 are particularly flexible in use.

[0030] It can preferably be provided that a depth profile 2 of the intaglio intaglio printing plate 1 is produced by engraving several engraving layers 4, 5, 6, 7, wherein the engraving layers 4, 5, 6, 7 are determined on the basis of a predetermined target depth profile 16.

[0031] The engraving layers 4, 5, 6, 7 are preferably produced in such a way that several essentially parallel engraving sections are engraved in an overlapping manner, whereby a smooth surface is removed in the engraving layer 4, 5, 6, 7. Particularly preferably, it can be provided that continuous engraving sections are produced, thus removing continuous lines and not creating a dot matrix. The overlapping engraving sections are exemplified in Fig. 5 which creates a smooth surface created by the engraving layer, as shown in Fig. 6 is shown as an example.

[0032] Particularly preferably, it can be provided that the engraving is carried out by means of a laser beam.

[0033] For this purpose, it can be particularly preferably provided that a printing plate consisting of metal, in particular brass, is engraved directly by the laser beam. In this context, "directly engraved" means that instead of first engraving a so-called master made of a less stable material such as plastic, and then molding the final intaglio intaglio plate 1 from this master, the intaglio intaglio plate 1 intended for printing is engraved directly by the laser beam. This eliminates a processing step in the production of the intaglio intaglio plate 1, and the associated errors can also be avoided. Brass offers the advantage of being both easy to process and, at the same time, able to withstand the high mechanical stresses of intaglio intaglio printing.

[0034] Preferably, a pulsed laser can be used as the laser. Such pulsed lasers do not emit the laser beam continuously, but rather in the form of periodically recurring short pulses, with the instantaneous output power of the laser during the pulse being a multiple of the time-averaged output power of the laser. This allows for targeted removal of material from the intaglio intaglio printing plate 1 without unduly high thermal stress on the intaglio intaglio printing plate 1.

[0035] It can be particularly preferably provided that an ultrashort pulse laser is used as the laser. Pulse lasers whose pulse duration is in the range of picoseconds, femtoseconds or attoseconds are referred to as ultrashort pulse lasers. Such an ultrashort pulse laser can, for example, have a pulse duration of a few picoseconds. Due to this short pulse duration and the high output power during a pulse of the ultrashort pulse laser, material of the intaglio intaglio printing plate 1 is essentially removed at specific points without neighboring areas being melted or vaporized. This eliminates the formation of burrs around the removed areas of the intaglio intaglio printing plate 1, whereby complex post-treatment of the intaglio intaglio printing plate 1, for example using chemicals or polishing, which has a negative impact on the quality of the engraving, can be omitted.The use of an ultrashort pulse laser advantageously results in significantly steeper flanks of the ablated areas. Furthermore, stable laser operation is achieved because the laser continuously emits pulses, whose impact on the intaglio printing plate 1 is controlled depending on the original.

[0036] Alternatively, it may be provided that a continuous laser is used as the laser.

[0037] Furthermore, it can alternatively be provided that the engraving layers 4, 5, 6, 7 and the micro-grooving 9, 10 are engraved by means of a stylus.

[0038] Furthermore, it can preferably be provided that the laser beam is moved in parallel lines across the engraving area to remove an engraving layer 4, 5, 6, 7, wherein in particular the movement speed of the laser beam is kept approximately constant in each subsequent line after an initial acceleration range up to a final deceleration range, and that the impact of the laser beam on the engraving area is controlled by means of a shutter element. The impact of the laser beam on an engraving area can be controlled by means of the shutter element depending on a template. This allows targeted engraving of the intaglio intaglio printing plate 1 depending on the template, even with a constant movement speed of the laser beam.

[0039] The intaglio intaglio printing plate 1 has, at least in some areas, an ink retention topography in the form of micro-grooves 9, 10. The ink retention topography is a topography of the intaglio intaglio printing plate 1 intended to prevent intaglio printing ink from being removed during the wiping step.

[0040] The micro-grooving 9, 10 is arranged in particular in the depth profile 2 of the intaglio intaglio printing plate. The micro-grooving 9, 10 can also be referred to as microtopography. The micro-grooving 9, 10 can preferably be in the form of grooves arranged at a distance from one another. These grooves can preferably be substantially parallel to one another.

[0041] The micro-grooves 9, 10 can be created by engraving individual micro-groove layers 3, 8. The micro-groove layers 3, 8 are similar to the other engraving layers, with one or more parameters being changed so that a micro-groove 9, 10 is created instead of a smooth surface. This is exemplified in the Fig. 7 und 8 illustrated.

[0042] Particularly preferably, it can be provided that the engraving is carried out by means of a laser beam, and that for engraving the micro-grooving 9, 10, the first line spacing 11 and the diameter of the laser beam are selected such that the micro-grooving 9, 10 is created. The first line spacing 11 is the distance between the centers of the individual engraving lines in the respective micro-grooving layer 3, 8.

[0043] For this purpose, it can be provided that for engraving the micro-grooving 9, 10 the first line spacing 11 of the laser beam is selected to be larger than for the other engraving layers 4, 5, 6, 7, whereby the micro-grooving 9, 10 can be produced particularly easily.

[0044] However, it can also be provided that for engraving the micro-grooving 9, 10 the first line spacing 11 of the laser beam is selected to be the same size as for the other engraving layers 4, 5, 6, 7 and the diameter of the laser is changed.

[0045] For this purpose, it may further be provided that the diameter of the laser beam for engraving the micro-grooves 9, 10 is selected to be larger than for the other engraving layers 4, 5, 6, 7. The first line spacing 11 can be adjusted accordingly.

[0046] Alternatively, it may be provided that for engraving the micro-grooving 9, 10 the diameter of the laser beam is selected to be smaller than for the other engraving layers 4, 5, 6, 7.

[0047] However, it can also be provided that for engraving the micro-grooving 9, 10 the diameter of the laser beam is selected to be the same as for the other engraving layers 4, 5, 6, 7 and the laser power and / or the first line spacing 11 are adjusted.

[0048] Preferably, it can further be provided that the at least one engraving layer 4, 5, 6, 7 is produced by engraving substantially parallel lines with a predetermined second line spacing 12, and that the second line spacing 12 is smaller than the first line spacing 11.

[0049] It may preferably be provided that the second line spacing 12 is kept constant.

[0050] It can also be provided that the first line spacing 11 is kept constant.

[0051] For engraving smooth surfaces, the second line spacing 12 can be approximately half the laser diameter, so that the superposition of the individual ablation profiles creates a smooth surface, as shown for example in Fig. 6 An overlay of individual Gaussian profiles or a laser engraving path is shown as an example in Fig. 5 shown.

[0052] Depending on the laser power, the laser diameter can preferably be 15 µm to 40 µm, in particular 18 µm to 38 µm, particularly preferably 20 µm to 35 µm.

[0053] The distance between the engraving lines can preferably be 10 µm, whereby the ratio of the distance to the laser diameter is 0.5 to approximately 0.33.

[0054] For engraving the micro-grooves 9, 10, it is particularly preferable to increase the distance between the engraving sections, especially with the same laser power, so that the individual ablation profiles overlap less. The ratio of distance to diameter is therefore increased, which is exemplified in the Fig. 7 und 8 is illustrated.

[0055] The ratio of the distance between the engraving paths to the laser diameter may preferably be at least 0.75, in particular at least 1, particularly preferably at least 1.5.

[0056] It can preferably be provided that, with a distance between the engraving sections of 25 µm to 50 µm, a height of the micro-grooving 9, 10 in the range of 2 µm to 7 µm is achieved for a micro-grooving layer 3, 8.

[0057] It can also be provided that with an increase in laser power and with a distance between the engraving lines of 60 µm to 100 µm, a height of the micro-grooving 9, 10 in the range of 8 µm to 16 µm is achieved.

[0058] The height of the micro-grooving 9, 10 is taken to be the difference between the highest and lowest points of the micro-grooving 9, 10, thus the difference between elevations and depressions within the micro-grooving 9, 10. The height of the micro-grooving 9, 10 is determined on the one hand by the laser power and on the other hand by the distance between the engraving lines.

[0059] To create an even higher micro-grooving 9, 10, it is particularly preferred that the micro-grooving layers 3, 8 are engraved multiple times. In this case, the existing micro-grooving 9, 10 is engraved with the same micro-grooving layer 3, 8 for the micro-grooving 9, 10, thereby increasing the height of the micro-grooving 9, 10.

[0060] It can further preferably be provided that essentially the entire surface of the depth profile 2 is provided with the micro-grooving 9, 10. This allows for particularly good ink retention of the intaglio printing ink on the intaglio intaglio printing plate 1 during the wiping step. The entire depth profile 2 is provided with a micro-grooving 9, 10, which further enhances the quality of the intaglio intaglio printing.

[0061] According to the invention, the micro-grooving 9, 10 is engraved last. This ensures that the micro-grooving 9, 10 is not affected by the engraving of subsequent engraving layers 4, 5, 6, 7.

[0062] According to the invention, an engraving layer 4, 5, 6, 7 is assigned to each depth based on the depth profile 2 to be engraved, wherein the engraving layer of a first depth is engraved after the engraving layer of a second depth, wherein the second depth is deeper than the first depth. The sequence of the engraving layers 4, 5, 6, 7 is selected such that the engraving layers 4, 5, 6, 7 are engraved in descending order of depth. It is advantageous in this case that if the sequence of engraving layers 4, 5, 6, 7 is reversed, the staircase effect is reduced, since the last layer is the widest and thus at least slightly overlaps previous layers. With such a reversal, the micro-grooving 9, 10 can be produced particularly easily.

[0063] The depth of an engraving layer 4, 5, 6, 7 is seen from the side of the intaglio intaglio plate 1 to be engraved.

[0064] In Fig. 1 The engraving layers 4, 5, 6 and the micro-corrugation layer 3 for generating a depth profile 2 of a first embodiment are shown as examples. In Fig. 1 , and later also in Fig. 3 The desired depth profile 16 is represented by the solid line. The levels of the engraving layers 4, 5, 6 and the micro-corrugation layer 3 are represented by dashed or dotted lines. The size of the area of ​​the individual levels within the desired depth profile 16 also represents the size of the respective engraving layers 4, 5, 6 and micro-corrugation layer 3. The third engraving layer 6 represents the deepest engraving layer. The second engraving layer 5 is the engraving layer arranged above the third engraving layer 6. The first engraving layer 4 is the engraving layer arranged above the second engraving layer 5 and therefore has a shallower depth than the engraving layer 5. The micro-corrugation layer 3 is the engraving layer by means of which the micro-corrugation 9 is produced.

[0065] Preferably, provision can be made for the third engraving layer 6 to be engraved first, followed by the second engraving layer 5, then the first engraving layer 4, and finally the micro-grooving layer 3. This reduces the stair-step effect and allows the micro-grooving 9 to be clearly formed.

[0066] In Fig. 2 a depth profile 2 with a micro-groove 9 is shown as an example, which is created by means of the sequence of the engraving layers 4, 5, 6 according to Fig. 1 was generated.

[0067] In Fig. 3 The engraving layers 4, 5, 6, 7 and several micro-corrugation layers 3, 8 for generating a depth profile 2 of a second preferred embodiment are depicted by way of example. Compared to the first preferred embodiment, an additional fourth engraving layer 7 appears, which is deeper than the third engraving layer 6, as well as two different micro-corrugation layers 3, 8: a first micro-corrugation layer 3 and a second micro-corrugation layer 8. The first micro-corrugation layer 3 is larger than the second micro-corrugation layer 8.

[0068] The depth profile 2 resulting from these engraving layers 4, 5, 6, 7 and micro-corrugation layers 3, 8 is shown as an example in Fig. 4 shown. Due to the two different micro-grooving layers 3, 8, two different micro-grooves 9, 10 were also created. The first micro-groove 9 was created solely by the first micro-groove layer 3. The second micro-groove 10 was engraved by both micro-groove layers 3, 8 and is therefore more pronounced than the first micro-groove 9.

[0069] An intaglio intaglio printing plate 1 typically has a predetermined wiping direction during its planning and production. The wiping direction is the direction in which the intaglio intaglio printing plate 1 is wiped, particularly with a doctor blade, after the intaglio printing ink has been applied. In particular, the head and foot of the intaglio intaglio printing plate 1 are predetermined, with the wiping direction running along this direction.

[0070] Preferably, the micro-grooves 9, 10 are not engraved parallel to the specified wiping direction. This results in good ink retention.

[0071] Particularly preferably, the micro-grooving 9, 10 can be engraved obliquely to the predetermined wiping direction. Therefore, the micro-grooving 9, 10 preferably does not run perpendicular to the wiping direction.

[0072] In particular, it can be provided that the micro-corrugation 9, 10 runs in an angular range to the wiping direction of at least 45°.

[0073] Preferably, it can be provided that the micro-corrugation 9, 10 extends in an angular range to the wiping direction of a maximum of 87°.

[0074] This allows for good ink retention of the intaglio printing ink on the intaglio printing plate 1 during the wiping step in the depth profile 2. It has been shown that this significantly improves the quality of the intaglio printing.

[0075] Particularly preferably, it can be provided that the intaglio intaglio printing plate 1 is set to a predeterminable electrical potential before the wiping step and is kept at the electrical potential during the wiping step, which is exemplified in Fig. 11 Here, the intaglio printing plate 1 is set to a negative potential V-. Dipole-like pigments, whose dipole is in the Fig. 11 indicated by + / - are therefore pulled more tightly to the micro-grooves 9, 10 of the intaglio intaglio plate 1 and are pushed or removed less strongly from the depth profile 2 during the wiping step than pigments and other color components marked with n.

[0076] The intaglio printing ink contains color pigments that either have a permanent dipole moment or in which a dipole moment can be induced by an electrostatic field. The intaglio printing plate 1 is preferably made of metal and is set to an electrical potential V- before or after the ink application step, but in any case before the wiping step. As a result, the pigment dipoles align in the resulting electrostatic field and are attracted to the intaglio printing plate 1. During the wiping step, increased ink retention on the intaglio printing plate 1 is achieved.By engraving a micro-groove 9, 10, in particular by the protruding elements, such as points, of the micro-groove 9, 10, a locally higher field strength is achieved, whereby the attraction, in particular at the points of the micro-groove 9, 10, is higher than at the planum of the intaglio intaglio printing plate 1. Before the printing process, the intaglio intaglio printing plate 1 is grounded to reset the potential.

[0077] The advantage here is that multi-tonality in intaglio printing can be easily controlled via the electrostatic properties of the pigments. This allows for local variation in the color tone and also allows for dynamic effects.

[0078] This results in a synergistic effect, since the field effects are locally increased by the peak effect of the unevenness of the micro-grooving 9, 10, which enables particularly good ink retention.

[0079] It may further preferably be provided that the intaglio intaglio printing plate 1 is magnetized via a predeterminable external magnetic field before the wiping step.

[0080] In this case, the intaglio intaglio printing plate 1 is intended to contain color pigments with hard or soft magnetic properties. The intaglio intaglio printing plate 1 consists in particular of a metal with ferromagnetic properties and is magnetized via an external magnetic field before the wiping step. The color pigments are magnetostatically attracted to the intaglio intaglio printing plate 1 and are therefore less easily removed during the wiping step. Here, too, a locally higher field strength is achieved at the tips of the micro-grooves 9, 10, whereby the attraction is higher, in particular at the tips of the micro-grooves 9, 10, than at the flat surface of the intaglio intaglio printing plate 1. Before the printing process, the magnetic field of the intaglio intaglio printing plate 1 is reset in order to facilitate the ink transfer from the intaglio intaglio printing plate 1 to the object to be printed.

[0081] The advantage here is that multi-tonality in intaglio printing can be easily controlled using the magnetostatic properties of the pigments. This allows for local variation in the color tone and also allows for dynamic effects.

[0082] Here, too, a synergy effect results, since the field effects are locally increased by the peak effect of the unevenness of the micro-grooving 9, 10, which enables particularly good ink retention.

[0083] It can be specified that the electric and / or magnetic field is not reset before the printing process, meaning that no grounding is applied or demagnetization is not performed. In this case, the dipole pigments are oriented according to the field direction during the printing process. Using pigments that exhibit different color impressions depending on their orientation can achieve a local variation in the color tone.

[0084] It may also be particularly preferred that an intaglio printing ink with pigments of different colours and sizes is used to print the security feature.

[0085] In particular, it can be provided that the intaglio printing ink is not a powder ground to a uniform size, but has pigments of different shapes and sizes.

[0086] In the Fig. 9 A multi-tonal print image 13 is shown as an example, using an intaglio printing ink with two different pigments of different sizes.

[0087] The Fig. 10shows, by way of example, an arrangement of pigments of different sizes in a depth profile 2 of an intaglio intaglio printing plate 1. Large pigments 14 can be retained particularly well in a partial area with a deeply formed micro-groove 10. Between and next to the large pigments 14, higher concentrations of small pigments 15 with isolated large pigments 14 can also be arranged in a further partial area. This creates a multi-tonality in the finished printed image, which can be specifically influenced by means of one or more micro-grooves 9, 10. In this case, the large pigments 14 can be pigments of a first color, for example, and the small pigments 15 can be pigments of a second color, for example.

[0088] Micro-grooves 9, 10 can preferably be engraved with different heights, adapted to the size of different pigments. The shape, in particular the height of a micro-groove 9, 10, and the spacing of the individual grooves from one another can essentially be adapted to the size of a pigment.

[0089] It can also be provided that two or more than two micro-corrugations 9, 10 with different heights are arranged next to each other.

[0090] Furthermore, dynamic effects can be created using pigment flakes with a color variation via thin-film interference.

[0091] By means of one or more micro-grooves 9, 10, which are adapted to the shape and size of the pigments and specifically selected in different areas of the depth profile 2 of the intaglio intaglio printing plate 1, the different pigments can be retained particularly well during the wiping step.

Claims

1. Method for engraving an intaglio printing plate (1), wherein a depth profile (2) of the intaglio printing plate (1) is produced by engraving a plurality of engraving layers (4, 5, 6, 7), wherein, based on the depth profile (2) to be engraved, an engraving layer (4, 5, 6, 7) is assigned to each depth, wherein the sequence of the engraving layers (4, 5, 6, 7) is determined by the depth profile (2) to be engraved, and wherein the engraving layers ( wherein, on the basis of the depth profile (2) to be engraved, each depth is assigned an engraving layer (4, 5, 6, 7), wherein the sequence of the engraving layers (4, 5, 6, 7) is selected such that the engraving layers (4, 5, 6, 7) are engraved in descending order according to their depth, wherein the engraving layer (4, 5, 6, 7) of a first depth is engraved after the engraving layer (4, 5, 6, 7) of a second depth, wherein the second depth is deeper than the first depth, wherein at least one region of the depth profile (2) of the intaglio printing plate (1) is provided with a micro-corrugation (9, 10) for producing an ink retention topography, wherein the micro-corrugation (9, 10) is produced by engraving substantially parallel lines with a predetermined first line spacing (11), wherein the micro-corrugation (9, 10) is engraved last.

2. Method according to claim 1, characterized in that the engraving is carried out by means of a laser beam, and that for engraving the micro-corrugation (9, 10), the first line spacing (11) and the diameter of the laser beam are selected such that the micro-corrugation (9, 10) is produced.

3. Method according to claim 1 or 2, characterized in that the engraving layers (4, 5, 6, 7) are produced by engraving essentially parallel lines with a predetermined second line spacing (12), and in that the second line spacing (12) is smaller than the first line spacing (11).

4. Method according to one of claims 1 to 3, characterized in that the micro-corrugation (9, 10) is not engraved parallel to a predetermined wiping direction.

5. Method according to one of claims 1 to 4, characterized in that substantially the entire surface of the depth profile (2) is provided with the micro-corrugation (9, 10).

6. Intaglio printing plate (1) with an ink-retaining topography embodied as micro-corrugation (9, 10), manufactured according to a method according to one of claims 1 to 5.

7. Method for printing a security feature with an intaglio printing plate (1) according to claim 6, wherein in an ink application step, an intaglio printing ink is applied to the intaglio printing plate (1), wherein, in a wiping step, excess intaglio printing ink is wiped off the intaglio printing plate (1) along a wiping direction, and wherein, in a printing step, the intaglio printing ink is transferred from the intaglio printing plate (1) to the object to be printed.

8. Method according to claim 7, characterized in that the intaglio printing plate (1) is set to a predeterminable electrical potential before the wiping step and is maintained at the electrical potential during the wiping step.

9. Method according to claim 7, characterized in that the intaglio printing plate (1) is magnetized via a preselectable external magnetic field before the wiping step.

10. Method according to any of claims 7 to 9, characterized in that an intaglio printing ink with pigments (14, 15) of different colors and different sizes is used to print the security feature.