DE102020205495A1 - Printing form, in particular relief printing plate, and a method for producing the same - Google Patents

Abstract

The present invention relates to a printing forme 1 with at least one relief printing area 2 for letterpress printing, which is provided with a predetermined pattern 4 in the form of grooves for gravure printing and is intended for the application of a color and / or a film to its surface 3, the Grooves are preferably produced by etching the printing form and are designed such that the grooves have walls 4a, 4b, the surface of which in an upper region of the groove each form an angle α of 70 ° to 90 ° with a plane of the relief printing region 2 and the surface of the wall in a lower region of the groove, in particular in a bottom region of the groove, is designed / shaped at an angle to the opposite wall. The present invention also relates to a two-stage etching process and a single-stage etching process for producing a printing form, in particular printing form 1.

Description

Technical area

The invention relates to a printing form, in particular a relief printing plate, which is used as a cliché for direct image printing. The present invention also relates to a method for producing a printing form of the generic type.

State of the art

In the strong competition of the packaging industry and increasingly in corporate design of companies, it is important to attract the attention of customers with new visual and haptic effects. The most common use in the finishing of particularly high-quality packaging, business cards and other advertising media such as labels is hot foil stamping, also known as foil stamping.

Here, under the effect of pressure, temperature and contact time, transfer layers of an embossing foil are transferred to the material with the help of an embossing tool (embossing die / embossing cliché), which undergoes a permanent change in shape. These stamps are usually made of magnesium, copper or steel and are produced using an etching process.

In order to counteract the increasing trade in plagiarism, in addition to unusual product design, holographic effects in the form of protective patterns are also increasingly playing a role. For this purpose, embossing forms are required that allow a combination of letterpress and gravure printing. The design of the gravure pattern of the embossing stamp in the form of grooves or the guilloche pattern (grid of crossed lines) enables the printing of protective patterns with holographic elements or lenticular effects (images that change with the viewing angle), as can be found on securities , will be realized.

Embossing dies that enable both letterpress and gravure printing are currently manufactured with the help of CNC milling using micro and nano engraving techniques. However, the problem here is that due to the diameter of the respective milling head or a mechanical effect of the engraving on the metal, which can deform the walls of adjacent grooves, only a maximum image resolution of 20 lines per centimeter can be achieved. This resolution is often not sufficient for high security and quality standards. This is particularly due to the fact that the security of the securities is guaranteed, among other things, by the uniqueness of the protective pattern, which is directly dependent on the line density and the repetition accuracy of these lines on the print.

Furthermore, when engraving the grooves to a depth of 20 to 80 µm, the groove walls become inclined due to the shape of the engraving pen, so that the line boundaries do not always have a clear and precise image when printing.

In addition, 10 times the processing time is required for the production of an embossing stamp with the graphic technique compared to production with the etching process, which means that production from batch size 1 cannot be economically implemented. One of the reasons for this is that the shape has to be machined after milling or engraving in order to remove burrs and chips.

Specifically, holograms and protective patterns largely consist of a pattern of very fine point and strip-shaped structures. While the pattern in most holograms consists of black zones within a translucent film, in certain types of holograms it exists in the form of elevations and depressions on the surface. These structures can be duplicated with the help of embossing processes. Embossing tools are used for this, on the surfaces of which the negative forms of the structures are present. As already mentioned at the beginning, the production of the embossing tools for holographic applications and protective patterns is realized according to the current state of the art with the help of different milling and engraving techniques.

Some manufacturers of such printing plates, which are used, for example, for 2D holograms, use magnesium plates with a thickness of 1 to 7 mm or micro-engraved brass plates with a thickness of 3 to 7 mm. The holographic effect is created by changing reflections or light refractions and shading effects of the embossed image. The production of commercially available three-dimensional hologram foils, such as those used for the production of hologram labels, also requires elaborately produced master holograms and the corresponding embossing stamps.

In a further known method for producing embossing blocks for embossing holograms in metallic sheet materials, a holographic master structure is transferred to a silicon substrate by means of a maskless imagesetter in photoresist. The embossing tool is then manufactured in a galvanic molding process. To generate the holographic effect, the surface of the sheet is reshaped so that it is illuminated with white light, depending on the viewing angle reflects different colors, which makes the motif seem to lie behind the surface. However, this method is also characterized by a very high expenditure of time and energy.

Etching is an alternative to the production of embossing dies or embossing clichés using machining processes such as milling and engraving. This process is particularly established in the production of embossing clichés for hot foil stamping and enables cost-effective production from batch size 1. For the etching process, automatic etching machines are used used. In contrast to the production of PCBs or the steel etching of molded parts, the metal is not etched through for the production of embossing plates, but a contour is etched into the solid material. Contour etching is much more difficult, since parameters such as acid strength, temperature of the acid bath, rotation of the machine blades in the acid bath and also the proportion of already dissolved metal in the acid bath have an influence on the etching speed and thus on the etching depth after a certain time. In addition, these parameters also influence the quality of the etched image.

Only one-step etching processes are used in the production of embossing clichés by means of etching technology. This results in a uniform contour depth. However, the different depths required for holographic effects are not achieved with the currently established process sequences.

Due to the high costs for the production of embossing clichés and stamps for the production of 2D holograms, a finished endless hologram foil with a scattering pattern, which can be freely placed, is usually used to produce holographic effects. The holographic effect of these foils is only simulated by a color change. 3D effects and lenticular effects cannot be achieved with this.

In the area of hot foil stamping, the optical and haptic effects are currently only achieved through the protruding surface and the contrast between the foils and the printing material. The direct hot foil stamping of holographic effects and lenticular effects is not possible with the stamping plates currently produced by means of the one-step etching process and therefore the object of the present invention to be solved is part of the present invention.

Presentation of the invention

The invention is based on the object of providing a printing form, in particular a relief printing plate or an embossing block, which enables the printing of holographic images, in particular holographic protective patterns, and lenticular effects, in particular in the area of hot foil stamping. Furthermore, the present invention relates to a method for producing a generic printing form that, on the one hand, enables such a printing form to be produced in the first place and, on the other hand, enables cost-effective and time-saving production.

This object is achieved by a printing form according to claim 1 and a method for producing a generic printing form according to claim 11. Preferred developments of the invention are specified in the dependent claims, the subject matter of the claims relating to the printing form in the context of the two methods for producing a printing form can be used and vice versa. Furthermore, the process steps or process features described in the context of the first or two-stage etching process for producing the printing form can be used in the second or one-stage etching process and vice versa.

One of the basic ideas of the present invention is that, on the one hand, a printing form is provided which has at least one relief printing area for letterpress printing, with a pattern or image (e.g. image of a protective pattern) in the form of grooves for gravure printing being provided in the relief printing area, with the grooves have walls, the surface of which is formed approximately perpendicular to a plane of the relief printing region and the surface of the wall in a bottom region of the groove is designed obliquely to the opposite wall.

Another basic idea of the present invention is to provide a two-stage etching process for producing a generic printing form, the pattern or image (image of the protective pattern or of holographic elements) being transferred to a photoresist-coated form or plate in a first step, then in a first step Etching process, the pattern or image in the form of grooves is etched into the material of the mold or plate and, in preparation for a second etching process for the high-pressure area, a protective solution is introduced into the previously etched grooves in order to seal them. The actual embossing motif, the relief printing area for the letterpress printing, is then etched with the second etching process.

In this way, a printing form can be provided which, on the one hand, combines the advantages of the two printing techniques “letterpress” and “gravure”, whereby, for example, the direct hot foil stamping of holographic effects and lenticular effects is made possible Embossing quality or printing quality compared to known printing forms, which are realized by means of milling and engraving techniques, can be increased considerably. The improved embossing quality can be achieved on the one hand by increased image resolution, since the distances between individual lines are no longer limited by the tool size and plastic deformation that can be caused by the action of the tool, in particular the engraving pen. This makes it possible to increase the achievable line density to up to 90 lines per 1 cm and more. On the other hand, the achievable groove contour, in particular the fact that the groove walls are straight, i.e. approximately perpendicular to the printing surface of the relief printing area, at least in an upper region of the groove, contributes to an improvement in the embossing quality, in particular an increase in the accuracy of the line boundaries of the pattern or picture at. Furthermore, the production of the printing form in the two-stage etching process enables a drastic reduction in the processing time compared to the conventional milling and engraving techniques, whereby a cost-effective and time-saving production process can be provided.

According to one aspect of the present invention, a printing form, in particular a relief printing plate, has at least one relief printing area for letterpress printing, which is provided with a predetermined, additional pattern in the form of grooves for intaglio printing and for the application of a color and / or a film over its entire area Surface is intended on. The grooves are preferably produced by etching the printing form and are designed in such a way that the grooves have walls, the surface of which in an upper region of the groove each form an angle α of 70 ° to 90 ° with a plane of the relief printing region and the surface of the wall in a lower region of the groove, in particular in a bottom region of the groove, is designed at least partially obliquely to the opposite wall.

It is also advantageous if the two opposing walls of the grooves in the upper area each form an angle α of 80 ° to 90 °, preferably 85 ° to 90 °, with the plane of the relief printing area and the opposing walls in the lower area of the Grooves preferably have an angle β of 0 ° to 20 °, preferably 5 ° to 15 °, to an imaginary line that is parallel to the plane of the relief printing area, so that the groove has the shape of a blind hole in cross section.

According to a further aspect, the upper region of the groove walls extends into the printing form, in particular into the relief printing plate, to a depth of 30 to 500 μm.

Furthermore, it is preferred if an aspect ratio between the upper region and the lower region of the groove is 3 to 1, preferably 5 to 1, and more preferably 10 to 1.

Here, the grooves of the additional pattern can advantageously have a depth of 50 to 1000 μm, preferably 70 to 700 μm, more preferably 80 to 600 μm.

Furthermore, it is preferred if a height (thickness) of the printing form surface on the side of the relief printing area is from 900 to 1800 μm, preferably from 1000 to 1300 μm. Here, under height or thickness, the portion that was etched away from the original printing form or relief printing plate is to be provided in order to form the relief printing area.

Here, within the scope of the present invention, the term “printing forme surface” is to be understood as the area of the printing forme or the relief printing plate to which, for example, a color for printing is applied later.

According to a further embodiment, the printing form, in particular the printing plate, is at least partially made of copper, magnesium, zinc, steel or the like.

Furthermore, it is advantageous if at least a section of the surface of the relief printing area has a grain structure which is formed by grid points distributed on the surface, the depth of the grain structure depressions (grid points) being preferably 5 to 25 μm, more preferably 10 to 35 μm . It is also preferred here if the grid points are distributed uniformly on the surface.

The relief printing area preferably has at least one area which is not provided with the pattern for intaglio printing, i.e. is designed as a usual area for typographic printing. Additionally or alternatively, at least one further relief printing area can be provided which has no pattern for intaglio printing and thus represents a common area for the typographic printing process.

According to a further embodiment of the present invention, the surface of the printing form, in particular a relief printing plate made of steel, is provided with a metallic protective layer at least on the side of the relief printing area, which is preferably selected from the titanium group. It is also preferred here that the protective layer is applied by a metal spraying process such as flame, powder, arc and plasma spraying.

In this way, the wear resistance of the printing form, in particular the surface provided with the relief printing area, can be increased and the service life of the printing form can thus be increased.

• Einbringen von Rillen eines vorgegebenen Musters für den Tiefdruck in einen Reliefdruckbereich einer Druckform, insbesondere einer Reliefdruckplatte, mittels eines ersten Ätzprozesses,
• Verschließen der durch den ersten Ätzprozess erzeugten Rillen mittels bevorzugt einer Schutzlösung, und
• Entfernen des Materials der Druckform außerhalb eines Musterumrisses des vorgegebenen Musters, insbesondere außerhalb eines Reliefdruckbereichs, mittels eines zweiten Ätzprozesses, um den Reliefdruckbereich für den Hochdruck zu bilden.

The present invention also relates to a method for producing a printing form, in particular the printing form described above, comprising at least the following steps:

• Introduction of grooves of a predetermined pattern for gravure printing into a relief printing area of a printing form, in particular a relief printing plate, by means of a first etching process,
• Closing the grooves produced by the first etching process by means of preferably a protective solution, and
• Removal of the material of the printing form outside a pattern outline of the predetermined pattern, in particular outside a relief printing area, by means of a second etching process in order to form the relief printing area for the letterpress.

Furthermore, it is preferred if, before the first etching process, an image of the pattern to be produced for gravure printing is applied to a photosensitive layer of the printing form and developed. Additionally or alternatively, an image of a final embossing motif for the relief area for the letterpress can be applied and developed on a photosensitive layer of the printing form, which was preferably applied to the printing form after the first etching process, before the second etching process.

Furthermore, it is advantageous if the first and / or second etching process or the single-stage etching process takes place with simultaneous rotation of the printing form and rotation of blades for stirring the etching solution, the rotation of the printing form preferably being carried out at a constant speed and the rotation of the Shoveling is preferably carried out at a variable speed.

Here, the first and / or second etching process or the single-stage etching process are usually carried out in automatic etching machines that have a rotary turntable on which the printing form to be etched, in particular a relief printing plate, is clamped and then rotated during the etching process. The rotary platter can be pivoted out of the automatic etching machine in order to facilitate the attachment of the printing form to the rotary platter and is usually in a horizontal orientation during the etching process.

It is also advantageous to use two pairs of blades with different sizes in the automatic etching machine. The first pair of blades here has a common size with a diameter of approximately 110 to 120 mm. The second pair of blades is provided with a smaller diameter, for example with a diameter of approx. 105 to 115 mm. In this way, the smaller pair of blades creates a much finer spray mist, which significantly increases the imaging quality of the etching process.

The absolute diameter of the two pairs of blades is not decisive here, what is important is that the smaller pair of blades is slightly less immersed in the etching liquid than the larger pair of blades, the difference in diameter being selected so that the pair of blades with the smaller diameter by approx. 1 to 3 mm less deep than the pair of blades with the larger diameter is immersed in the etching liquid. In this way it is made possible for the pair of blades with the smaller diameter to spray the etching liquid more finely, that is to say to produce a finer spray mist, as a result of which the imaging quality of the etching process can be significantly increased. The pair of blades with the smaller diameter dips approx. 5 to 10 mm into the etching liquid. The pair of blades with the larger diameter, on the other hand, dips about 8 to 15 mm deep into the etching liquid.

Here, depending on the size of the automatic etching machine, 5 to 9 pairs of blades can be provided on the rotating shafts. The decisive advantage of this arrangement lies in the fine misting of the etching bath on the plate to be etched.

It is also preferred if, for the formation of the grooves with an approximately vertical wall surface, the etching in the first etching process is carried out for a predetermined first time t ₁ with a first rotation speed of the blades and then in a second step for a predetermined second time t ₂ a second rotational speed of the blades is carried out, the rotational speed of the first rotational speed being selected to be higher than the rotational speed of the second rotational speed, in particular being selected to be 70 to 150 rpm higher.

Furthermore, it is advantageous if the first rotation speed of the blades is in a range from 500 to 700 rpm, preferably 500 to 630 rpm, and the second rotation speed of the blades is preferably in a range from 400 to 600 rpm 480 to 530 rpm.

To the multi-stage process described above with a first etching process and a second etching process of a printing form, in particular To simplify a universal printing form (printing form / image carrier) of a mixed type, a method for producing a generic printing form is proposed according to a further aspect of the present invention, in which the two-stage etching process can be dispensed with.

For this purpose, a special film is proposed which, on the one hand, restricts all image properties (patterns) with an etching depth of 70 to 700 µm and, on the other hand, restricts the etching depth of the printing elements to a required value of 10 to 35 µm by achieving the highest possible parameters with the selected printing elements. The superfluous metal in the non-printing areas can be removed from all sides to a depth of 1,800 to 3,500 µm using the continuous etching process.

The production of such an image on a light-sensitive layer is achieved by producing a grid with dimensions of points and a line thickness of 10 to 120 µm. The distance between image-free or pattern-free areas can be 10 to 50 µm.

By producing such a film (light-sensitive layer), the production of two separate films, as in the above two-step process, can be dispensed with, which on the one hand simplifies the production of the film or the light-sensitive layer, since it is not necessary to close the two films overlay, that is, to apply the second film precisely at the position on the printing form where the first film was previously applied, and on the other hand, a second etching process can be dispensed with. This also has the advantage that no protective layer has to be applied to the printing form, in particular the grooves that were produced in the previous first etching process. Accordingly, the entire manufacturing process can be simplified and thus the costs can be reduced. Furthermore, by eliminating the superposition of the previous two films, the print quality can be increased.

• Aufbringen auf eine lichtempfindliche Schicht der Druckform ein Abbild eines endgültigen Prägemotives, wobei das Abbild die Kontur (Linien) mindestens eines Reliefdruckbereichs für den Hochdruck sowie die Kontur (Linien) mindestens eines vorgegebenen Musters für den Tiefdruck umfasst,
• Einbringen von Rillen des vorgegebenen Musters für den Tiefdruck in den Reliefdruckbereich und Entfernen des Materials der Druckform außerhalb der Kontur des mindestens einen Reliefdruckbereichs mittels eines einstufigen Ätzprozesses.

Accordingly, the present invention relates to a further method for producing a printing form, in particular the printing form described above, comprising at least the following steps:

• Applying an image of a final embossing motif to a light-sensitive layer of the printing form, the image comprising the contour (lines) of at least one relief printing area for letterpress printing and the contour (lines) of at least one predetermined pattern for intaglio printing,
• Introducing grooves of the predetermined pattern for the gravure printing into the relief printing area and removing the material of the printing form outside the contour of the at least one relief printing area by means of a one-step etching process.

It is also advantageous if the image applied to the light-sensitive layer of the printing form has at least one further contour (lines) for a grain structure.

It is further preferred here that the contour of the film for the specified pattern has a line thickness of 10 to 120 μm and the distances between the lines are preferably in a range of 10 to 100 μm, which means the depth of the grooves of the specified pattern is limited to a range of 70 to 300 microns, and the contour for the grain structure has a line thickness of 10 to 50 microns and the distances between the lines are preferably in a range of 25 to 100 microns, so that the depth of the grain structure to a range of 10 to 35 µm is limited.

Furthermore, it is advantageous if a distance between image-free or pattern-free areas of the image applied to the light-sensitive layer of the printing form is between 10 and 50 μm, the line thicknesses of the respective contours being preferably selected such that, regardless of the duration of the etching process, none Depth is achieved which is greater than the predetermined areas 70 to 300 µm (grooves for gravure printing) or 10 to 35 µm (grain structure).

Figure list

• 1 eine Gesamtansicht einer Ausführungsform einer offenbarungsgemäßen Reliefdruckplatte;
• 2 zeigt eine Schnittansicht entlang der Linie A - A in 1,
• 3 zeigt eine vergrößerte Schnittansicht der Druckform von 1,
• 4 zeigt eine Gesamtansicht eines Films für einen ersten Ätzprozess zur Herstellung des Musters der in 1 gezeigten Ausführungsform für den Tiefdruck,
• 5 zeigt eine Gesamtansicht eines Films für einen zweiten Ätzprozess zur Herstellung des endgültigen Prägemotives für den Hochdruck,
• 6 zeigt eine Schnittansicht einer weiteren Ausführungsform einer offenbarungsgemäßen Reliefdruckplatte,
• 7 zeigt eine Gesamtansicht eines Films für das einstufige Ätzverfahren,
• 8 zeigt ein universelles Beispiel einer Druckform mit verschiedenen Linien und Rasterpunkten hergestellt im einstufigen Ätzverfahren,
• 9 zeigt eine vergrößerte Schnittansicht von Rillen, die mittels des erfindungsgemäßen Verfahrens hergestellt wurden, und
• 10 zeigt eine schematische Seitenansicht zweier Schaufelpaare für einen Ätzautomaten die auf einer gemeinsamen Drehwelle angeordnet sind.

Further features and advantages of a device, a use and / or a method emerge from the following description of embodiments with reference to the accompanying figures. Further modifications of certain features mentioned in this context can each be individually combined with one another in order to form further embodiments. From these figures shows:

• 1 an overall view of an embodiment of a relief printing plate according to the disclosure;
• 2 FIG. 13 shows a sectional view along the line A - A in FIG 1 ,
• 3 FIG. 13 shows an enlarged sectional view of the printing form of FIG 1 ,
• 4th FIG. 13 shows an overall view of a film for a first etching process to produce the pattern of FIG 1 shown embodiment for gravure printing,
• 5 shows an overall view of a film for a second etching process to produce the final embossing motif for the letterpress,
• 6th shows a sectional view of a further embodiment of a relief printing plate according to the disclosure,
• 7th shows an overall view of a film for the one-step etching process,
• 8th shows a universal example of a printing form with different lines and raster points produced in a one-step etching process,
• 9 FIG. 11 shows an enlarged sectional view of grooves produced by the method according to the invention, and FIG
• 10 shows a schematic side view of two pairs of blades for an automatic etching machine, which are arranged on a common rotating shaft.

Description of embodiments

The same reference symbols, which are listed in different figures, designate identical, corresponding, or functionally similar elements.

1 shows an overall view of an embodiment of a relief printing plate according to the disclosure. Again 1 can be removed, has the relief printing plate according to the disclosure 1 a relief printing area 2 for high pressure, which in the embodiment shown has the shape of an oak tree leaf with two acorns arranged below it. Furthermore, the relief printing plate shown 1 a pattern 4th that is in the relief printing area 2 is arranged and is used for gravure printing. The pattern 4th in the embodiment shown is intended to emphasize the leaf edges of the leaves (oak tree leaves) as well as the sleeve of the acorns or to give them a structure. The relief printing area 2 is here for the application of a color or a film on its entire surface 3 certainly. The non-printing area 9 which is etched away by the second etching process described later is highlighted by hatching. When the printing form is used later, no color is applied to this area, which is why it does not contribute to the printing result and is accordingly a non-printing area.

2 FIG. 13 shows a sectional view along the line A - A in FIG 1 . As the 2 As illustrated, a relief printing plate according to the disclosure can have a thickness of 1 to 7 mm, the relief printing area 2 , which is produced by the second etching process, can have a height or thickness of 0.9-1.8 mm, for example. In the embodiment shown, the relief printing plate 1 several relief print areas (three oak tree leaves and two acorns), each with etched patterns 4th , or grooves that were created by the first etching process, are provided. As the 2 can also shows the depth of the pattern 4th can be varied in a range from 70 to 700 µm. Furthermore, as also in 2 shown is the relief printing area 2 additionally with a grain structure 5 be provided (see also 3 ). The grain structure 5 can have a depth of 10 to 35 µm. The grain structure can be provided to further increase the degree of protection of the pattern. The grain structure 5 usually consists of uniformly on the surface 3 distributed grid points.

The application of the color to such a printing form or relief printing plate takes place evenly on the entire surface of the relief printing area by means of a conventional ink roller, which is used for printing according to the typographic process, or with a roller which is used for applying the color to a matrix Gravure printing is used (matrix roller) such that the entire surface 3 the printing area is covered with a relief pattern (for letterpress printing) with paint and the grooves of the etched pattern 4th be well filled with ink or foil for gravure printing, but without subsequently removing the excess of ink or foil from the printed material again. The thickness of the ink or foil on the printed materials for letterpress printing can vary between 6 and 30 µm.

3 FIG. 13 shows an enlarged sectional view of the printing form of FIG 1 and the sectional view of 2 . Again 3 can be seen on the right side of the figure, the bottom can be seen 6th of the grooves created by the first etching process 4th also have a line grid. The grid of lines on the floor 6th be formed by a grain structure in the form of a line grid and / or by engraved lines. Such line grids can be on the floor 6th the grooves 4th are provided which form the gravure printing area of the printing form, regardless of whether the respective relief printing area 2 with a grain structure 5 is provided or not. Usually the grid of lines is on the floor 6th generated during the first etching process.

Again 3 also clearly visible are the walls of the grooves 4th formed approximately vertically in an upper region of the grooves, ie to the surface 3 of the relief printing area 2 formed approximately vertically. the 3 further illustrates that the grooves 4th in a lower region, in particular in a bottom region of the grooves, run obliquely to the opposite wall of the same groove. Here are usually the grooves 4th deeper formed as the depressions of the grain structure 5 as well as the grooves of the line grid.

4th Fig. 13 shows an overall view of a film for a first etching process to produce the pattern 4th the in 1 Embodiment shown for intaglio printing, in particular for the leaf edges of the deciduous leaves and the structure of the sleeve of the acorn, which here as a grain structure 5 is trained. This film or photoresist (in English "photoresist") is applied to a prepared steel sheet (or substrate with a metal surface in preparation for the implementation of a first etching process. The photoresist with the correspondingly developed image serves as a mask for the subsequent etching process (resp. By means of the first etching process, grooves are created in the metal surface of the substrate in accordance with the shape of the image shown or of the lithographic mask produced thereby.

5 shows an overall view of a film for a second etching process to produce the final embossing motif for the letterpress. Again 5 can be removed, the second film has the shape of the outer contour to be produced of the final embossed motif to be imaged for the relief area 2 on. The second film or photoresist shown here is applied to the metal surface of the substrate after the grooves of the pattern have been created by means of the first etching process 4th were introduced into the metal surface and the previously applied photoresist was removed, preferably chemically removed. After applying the second photoresist and developing the image or the lithographic mask produced thereby, a second etching process is carried out, with the aid of which the material of the metal surface is removed outside the outline or the outer contour of the image, whereby the relief area is removed 2 for the high pressure with its surface 3 is created.

6th shows a sectional view of a further embodiment of a relief printing plate according to the disclosure 1 . Again 6th can be removed, a relief printing plate according to the disclosure 1 also enable a mixed printing form. Here the area (zone) 7th a relief printing area as described above 2 for the letterpress, its (printing) surface 3 with etched grooves for a pattern 4th or protective pattern, which is used for gravure printing, is provided. Furthermore, the printing form shown 1 an area 8th on, which has a relief printing area 2 B with no etched grooves or patterns 4th is provided and is therefore only intended for conventional typographic printing. In this case it will be on the area 7th Printing ink or foil applied, which changes its color, for example, under certain optical conditions, and on the area 8th , here is the area 8th In the form of a star, a conventional printing ink is applied. In both cases without removing the excess paint or film. The thickness of the ink or film applied to the relief printing areas 2a , 2 B can vary from 8 to 40 µm.

In this way, a printing form can be provided with which a plurality of protective patterns can be easily printed, which are distributed on the surface of the security to be printed with the protective background and main pattern. With the preferred use of the optically changing color, the two-color effect on the entire printing surface is enhanced by the fact that the grain structure and consequently the grid also have reflective facets with different orientations, which give the impression of different colors.

An embodiment of a method for producing a printing form according to the present invention is described in detail below by way of example. The process for producing a printing form, in particular a straight cliché for letterpress and gravure printing, begins with the use of a transparency (negative or positive) to apply a motif or image to be printed / embossed to a light-sensitive image under UV light and a specified exposure time Layer that is applied to the printing form, in particular the metallic surface of the relief printing plate (substrate).

This is followed by development in the development bath (stereo mixture) until a glossy image has developed on the exposure surface of the printing form. After the image has been etched with nitric acid, which is preferably done using a brush and approximately 6% nitric acid, a first etching process is carried out using an automatic etching machine at a solution temperature of 28 to 32 ° C, preferably 30 to 31.5 ° C . It is assumed here that a profile depth of approx. 0.2 µm is achieved with an etching time of one minute. The first etching process takes place with a rotating speed of the rotary turntable of 8 to 10 rpm, the rotating speed of the machine blades being 480 rpm for paper and cardboard and 450 to 530 rpm for leather.

After the printing form has been etched, it is rinsed and dried. In order to achieve a good intermediate depth in the range of 20 to 150 µm when etching small elements such as labels, coats of arms, medals, etc., etching with variable blade speeds is recommended. Here, for example, in the first few minutes, for example the first three minutes, the speed of the blades of the automatic etching machine can be increased by 100 rpm compared to the standard speed, ie the speed of the Shoveling reaches approx. 580 to 630 rpm. In the subsequent etching time, the speed of the blades is reduced to 480 to 530 rpm, the standard value. This allows the etching of small and closely spaced printing elements.

After performing the first etching process, with which the grooves 4th For gravure printing, these are sealed with a protective solution such as a retouching varnish. This is followed by a second etching process in order to deepen the non-printing areas of the printing sheet to 900 µm to 1800 µm. In other words, to remove the material from these areas.

7th Figure 13 shows an overall view of a film for the above-described one-step etching process. As already stated above, the film used for the one-step etching process, in contrast to the two films that are used in the two-step etching process, has all the image properties (patterns) necessary for the final motif. Here, the film shown is designed in such a way that, as in FIG 8th is shown, the picture elements (grooves) are limited to a depth of 70 to 300 µm, and the printing elements are limited to a required value of 10 to 35 µm. This is achieved in that the respective elements may only have a certain width. The production of such an image on a light-sensitive layer is achieved by producing a grid with dimensions of points and a line thickness of 10 to 120 µm. The distance between image-free or pattern-free areas can be 10 to 50 µm.

Furthermore, the 8th a universal example of a printing form with different lines and raster points, the printing form being produced by means of the one-step etching process described above. Again 8th can be removed, the printing forme 1 several relief printing areas 2 on, being a relief printing area (area (zone) with pattern 7th ) with a predetermined pattern in the form of grooves 4th (Fir tree) is formed, the grooves having a depth of 70 to 300 microns. There is also another relief printing area 2 B (Area (zone) without a pattern 8th ) formed, which does not have a predetermined pattern 4th (Grooves), the second relief printing area is corresponding 2 B a conventional printing area which is in the shape of a star.

Another printing area is ring-shaped around the relief printing area 2 B (Star) arranged by a grain structure 5 is realized. In this way, the printing form shown is provided with three different picture elements, namely conventional printing area (letterpress), gravure printing and grain structure. Which significantly improves the protection against counterfeiting.

9 Fig. 13 is an enlarged sectional view of grooves 4th which were produced by means of the method according to the invention. Again 9 can be seen, the grooves have walls 4a , 4b on, the surface of which in an upper region of the groove in each case an angle α of 70 ° to 90 ° with a plane of the relief printing area 2 form and the surface of the wall in a lower region of the groove, in particular in a bottom region of the groove, is designed obliquely to the opposite wall.

Here, the two opposite walls point 4a , 4b of the grooves in the upper area each make an angle α of 80 ° to 90 °, preferably 85 ° to 90 °, with the plane of the relief printing area 2 on and the opposite walls 4a , 4b preferably have an angle β of 0 ° to 20 °, preferably 5 ° to 15 °, in the lower region of the groove, to an imaginary line which is parallel to the plane of the relief printing region.

10 shows a schematic side view of two pairs of blades of an automatic etching machine which are arranged on a common rotating shaft. As can be seen from the figure, a pair of blades 10 a slightly smaller outer diameter than the other pair of blades 10 on, with the two blades of a pair of blades 10 , 11 are each arranged opposite one another on the rotating shaft, that is to say are each arranged around the rotating shaft distributed at an angle of 180 °. Correspondingly, the four blades are each arranged offset by an angle of 90 ° around the rotating shaft. In the example shown, the blades 10 with the smaller diameter has an outer diameter of 112 mm and the blades 11 with the larger diameter, an outer diameter of 116 mm. The shovels dive accordingly 10 with the smaller outer diameter 2 mm less into the etching bath.

It is evident to the person skilled in the art that individual features, each described in different embodiments, can also be implemented in a single embodiment, provided that they are not structurally incompatible. Likewise, various features that are described in the context of a single embodiment can also be provided in several embodiments individually or in any suitable sub-combination.

List of reference symbols

1

Printing form (or relief printing plate)

2

Relief printing area

2a

Relief printing area with pattern

2 B

Relief printing area without a pattern

3

surface

4th

Predefined pattern (grooves)

4a

Grooved wall

4b

Grooved wall

5

Grain structure

6th

floor

7th

Area (zone) with pattern

8th.

Area (zone) without a pattern

9.

Non-printing area

10

Pair of blades with a small diameter

11

Large diameter pair of blades

Claims (19)

Printing forme (1), in particular a relief printing plate, with at least one relief printing area (2) for letterpress printing, which is provided with a predetermined pattern (4) in the form of grooves for gravure printing and for applying a color and / or a film to its surface ( 3) is determined, characterized in that the grooves are preferably produced by etching the printing form and are designed in such a way that the grooves have walls (4a, 4b), the surface of which in an upper region of the groove each an angle α of 70 ° to Form 90 ° with a plane of the relief printing area (2) and the surface of the wall in a lower area of the groove, in particular in a bottom area of the groove, is designed obliquely to the opposite wall. Printing forme (1) Claim 1 , the two opposing walls (4a, 4b) of the grooves in the upper area each forming an angle α of 80 ° to 90 °, preferably 85 ° to 90 °, with the plane of the relief printing area (2) and the opposing walls (4a, 4b) in the lower region of the groove preferably have an angle β of 0 ° to 20 °, preferably 5 ° to 15 °, to an imaginary line which is parallel to the plane of the relief printing region. Printing forme (1) Claim 1 or 2 , the upper region of the groove walls (4a, 4b) extending into the printing forme (1) to a depth of 30 to 500 μm. Printing forme (1) Claim 1 or 2 , wherein an aspect ratio between the upper region and the lower region of the groove is 3 to 1, preferably 5 to 1, and more preferably 10 to 1. Printing form (1) according to one of the preceding claims, wherein the grooves of the pattern (4) have a depth of 50 to 1000 µm, preferably 70 to 700 µm, more preferably 80 to 600 µm. Printing forme (1) according to one of the preceding claims, the height of the printing forme surface 3 on the side of the relief printing area being 900 to 1800 µm, preferably 1000 to 1300 µm. Printing forme (1) according to one of the preceding claims, which is at least partially made of copper, magnesium, zinc, steel or the like. Printing forme (1) according to one of the preceding claims, in which at least a section of the surface (3) of the relief printing area (2) has a grain structure (5) which is formed by grid points distributed preferably evenly on the surface (3), the depth the grain structure depressions is preferably 5 to 50 μm, more preferably 10 to 35 μm. Printing forme (1) according to one of the preceding claims, wherein the relief printing area (2) has at least one area that is not provided with the pattern (4) for gravure printing, and / or at least one further relief printing area (2b) is provided which is not Has pattern (4) for gravure printing. Printing forme (1) according to one of the preceding claims, in which the surface (3) of the printing forme (1), in particular a relief printing plate made of steel, is provided on the side of the relief printing area (2) with a metallic protective layer, which is preferably selected from the titanium group and which is applied in particular by a metal spraying process such as flame, powder, arc and plasma spraying. Method for producing a printing form (1), in particular the printing form (1) according to one of the preceding claims, comprising the steps: Introducing grooves of a predetermined pattern (4) for gravure printing into a relief printing area (2) of a printing forme (1) by means of a first etching process, Closing the grooves produced by the first etching process by means of preferably a protective solution, and Removal of the material of the printing form (1) outside a pattern outline of the predetermined pattern (4), in particular outside the relief printing area (2), by means of a second etching process in order to form the relief printing area (2) for the letterpress. Procedure according to Claim 11 , wherein before the first etching process, an image of the to a photosensitive layer of the printing form generating pattern (4) for gravure printing is applied and developed, and / or before the second etching process on a light-sensitive layer of the printing form, which was preferably applied to the printing form after the first etching process, an image of a final embossing motif for the relief area (2) for which high pressure is applied and developed. Method for producing a printing form (1), in particular the printing form (1) according to one of the preceding claims, comprising the steps: Applying an image of a final embossing motif to a light-sensitive layer of the printing form, the image comprising a contour of at least one relief printing area (2) for letterpress printing and a contour of at least one predetermined pattern (4) for intaglio printing, Introducing grooves of the predetermined pattern (4) for the gravure printing into the relief printing area (2) and removing the material of the printing form (1) outside the contour of the at least one relief printing area (2) by means of a one-step etching process. Procedure according to Claim 13 , wherein the image applied to the light-sensitive layer of the printing form also has at least one further contour for a grain structure, the contour for the specified pattern (4) preferably having a line thickness of 10 to 120 μm and the distances between the lines preferably in one area from 10 to 100 microns, whereby the depth of the grooves of the predetermined pattern (4) is limited to a range of 70 to 300 microns, and the contour for the grain structure (5) has a line thickness of 10 to 50 microns and the distances between the lines are preferably in a range from 25 to 100 μm, whereby the depth of the grain structure is limited to a range from 10 to 35 μm. Procedure according to Claim 13 or 14th , wherein a distance between image-free or pattern-free areas of the image applied to the photosensitive layer of the printing form is between 10 to 50 μm, the line thicknesses of the respective contours being preferably selected such that, regardless of the duration of the etching process, no depth is reached that is larger than the predetermined ranges 70 to 300 µm or 10 to 35 µm. Method according to one of the Claims 11 until 15th , the first and / or second etching process or the single-stage etching process taking place with simultaneous rotation of the printing form and rotation of blades for stirring the etching solution, the rotation of the printing form preferably being carried out at a constant speed and the rotation of the blades preferably being carried out at a variable speed Speed is carried out. Procedure according to Claim 16 , wherein for the formation of the grooves with an approximately perpendicular wall surface, the etching in the first etching process or in the single-stage etching process is carried out for a predetermined first time t ₁ with a first rotation speed of the blades and then for a predetermined second time t ₂ with a second rotation speed of the Shoveling is carried out, wherein the speed of the first rotation speed is selected to be higher than the speed of the second rotation speed, in particular 70 to 150 U / min higher is selected. Procedure according to Claim 17 , the first rotation speed of the blades in a range from 500 to 700 rpm, preferably 500 to 630 rpm, and the second rotation speed of the blades in a range from 400 to 600 rpm, preferably 480 to 530 rpm min. Method according to one of the preceding Claims 11 until 18th , wherein after completion of the second etching process or the one-step etching process, the photosensitive layer is removed by means of a resin solvent and a metal protective layer, preferably from the titanium group, is applied, in particular sprayed, to the mold surface on the side of the relief printing area.

Images