Method and device for manufacturing moulds for engraved printing intended for production of security papers

FIELD: printing industry.

SUBSTANCE: invention relates to a method and device for manufacturing moulds for engraved printing, intended for production of security papers, which uses a laser beam (2) for engraving pattern (3, 3.1, 3.2, 3.3) of engraved printing directly on the surface of the moulding material (1), in particular metal, made with the ability of laser engraving. Laser engraving of the moulding material (1) is carried out in layers in several separate stages of engraving. The stages are carried out one after another with the absolute register so that the pattern (3, 3.1, 3.2, 3.3) of engraved printing is gradually engraved on the surface of the moulding material (1) to the required depth of engraving. The surface of the engraved moulding material (1) is cleaned from wastes of a process of laser engraving after each separate stage of engraving, while the laser engraving unit is in the inoperative state.

EFFECT: improvement of quality of engraving.

24 cl, 10 dwg

 

The technical field to which the invention relates.

This invention generally relates to the field of gravure printing, applied to the production of securities, including notes, tax stamps, ribbons with logos or labels, identity or travel documents, etc.

More precisely, this invention relates to a method and apparatus for the manufacture of printed forms for gravure printing, designed for gravure printing sheets or rolls of securities that are based on direct laser engraving of the plate material, mainly metal plate material.

Background of invention

In printing technology is already known production of printing forms for gravure printing, designed for the production of securities, with the help of laser engraving.

For example, in International publication no WO 97/48555 A1 disclosed a method of directly etching a metal plate material, in which precise engraving tool, for example, laser engraving cutter, is directed in a predetermined path engraving, within a given contour and with a given depth of penetration, for removing material from the surface layer of the printing plate within a given path at a given depth. This engraving process is, essentially, a vector in the sense that the Les, laser engraving cutter follows a given trajectory of the tool corresponding to the engraving on the form of the figure gravure printing.

In European patent application no EP 1334822 A2 discloses a method and equipment for direct laser engraving forms for gravure printing or cylinders, in which the etching is performed by using a laser beam generated by a pulsed Nd-YAG laser (laser yttrium aluminate with neodymium). The engraving laser plate material is mounted on a platform with a motor drive, which can move relative to two axes of a rectangular coordinate system and which controls the computer; the computer also controls the actuation of the pulse laser and the mode of its operation. A pulsed laser is mounted so that it can move in the vertical direction, and its height relative to the platform is controlled through the motor, which is controlled by the computer, in order to adjust and focus the laser beam on the engraving form. Used an optical system with galvanometric motors to direct the laser beam at the focal lens which focuses the laser beam at a given point within a specified area of the engraving, which covers only a limited part of the entire surface of the printing form is. A pulsed laser, in particular, is designed to generate pulses, the capacity of which is much higher than the normal power lasers operating in continuous mode. This decision has one drawback: the engraving process requires recurrent local processing to process by etching the entire area of the printing form, because once processed area of the order of 100 mm × 100 mm Provided by the optical system with the appropriate focal length to process each specified area within the site engraving. The angle of incidence of the laser beam relative to the surface of the printing form thus changes depending on the position of the laser beam relative to the location of the engraving area, thereby potentially leading to uneven etching. This process, moreover, requires a very high precision, so that between adjacent zones engraving not have any overlapping or gaps.

In International publication no WO 2006/045128 A1 disclosed a system of direct laser engraving for the manufacture of forms for gravure printing, which uses technological approach similar to that described in the aforementioned European patent application no EP 1334822 A2, that is, laser engraving plate material analogues is but mounted on movable relative to the coordinate system x-y platform and control the laser, to engrave a limited portion of the surface of the printing form. For more details about this system of direct laser engraving can be found in the article Harald Deinhammer, Daniel Schwarzbach, Rudolf Kefeder and Peter Fajmann entitled "The Memorandum of direct laser engraved intaglio printing plates on banknote security" ("the Influence of forms for gravure printing, is made by way of direct laser engraving, on the security of banknotes"), Proceedings of SPIE, Vol.6075, 2006, 607503-1 to 607503-11 (hereinafter referred to as Deinhammer 2006). The area of the engraving of this system is approximately 70 mm × 70 mm, and this implies that at one time may be engraved only a limited portion of the drawing gravure printing, and that the engraving process should be repeated with high precision so that there were no visible overlaps or gaps between adjacent engraved regions. As disclosed in International publication no WO 2006/045128 A1, it requires equal intervals of time of calibration operations, which are laborious and time-consuming.

There is also another drawback of the system of direct laser engraving as described in International publication no WO 2006/045128 A1, due to the fact that the angle of incidence of the laser beam relative to the surface of the printing form changes depending on the positioning of the laser beam relative to the location is the I of the engraving area, that potentially leads to heterogeneity of engraving and what to avoid.

Another disadvantage of this system of direct laser engraving (which is also characterized by the technology disclosed in International publication no WO 97/48555 A1) is that the data used to control the unit laser engraving, based mainly on data vectorized graphics. This implies that the time of engraving will increase with increasing complexity of the sketch, as discussed in Deinhammer 2006.

Further discussion of direct laser engraving forms for gravure printing can be found in International publication no WO 2005/002869 A1 and in the related article Harald Deinhammer, Franz Loos, Daniel and Peter Schwarzbach Fajmann, entitled "Direct Laser Engraving of an Intaglio Printing Plates" ("Direct laser engraving forms for gravure printing), Proceedings of SPIE, Vol.5310, 2004, pp.184-193 (hereinafter referred to as Deinhammer 2004). According to International publication no WO 2005/002869 A1, printing form, which is made or has a top layer made of brass or alloy, engraved directly by the laser and, after it is fully engraved, is cleaned to remove any residue of the molten material after the process of laser engraving; the cleanup operation is a chemical treatment in a bath of acid is of astora, before the surface of the form will, in the end, polished and chrome plated. Before any chemical treatment can be carried out pre-cleaning the surface of the engraved printing forms of solid carbon dioxide, by spraying pellets of solid carbon dioxide (see also Deinhammer 2006). Proposed chemical postprocessing engraved printing plates, as well as pre-treatment of solid carbon dioxide, is quite aggressive and can lead to deterioration of the quality of the engraving, if this process is not controlled and will not run properly. In addition, the postprocessing engraving pretreatment of solid carbonic acid and treatment with acidic solution to cause damage because they can lead to differences in the engraving and the lack of repeatability, that is, the differences between the two forms for gravure printing, made on the same sketch.

In International publication no WO 03/103962 A1 on behalf of the Applicant of the present invention, which is incorporated herein in its entirety by reference, discloses a variety of approaches to the manufacture of engraved forms for gravure printing. While the initial sketch, which will be played engraving, designed in the CAD system using vector and/or raster graphics, OK is Nately sketch is converted into a so-called depth map, which usually consists of a three-dimensional data about the image element gravure printing, reproducing the pattern of gravure printing, where the intensity of each picture element is represented by the depth to which will be engraved in the appropriate place in printed form. Then, on the basis of this plan the depths of the control unit of the laser engraving machine to perform a sequence of elementary steps engraving corresponding to each picture element in terms of the depths. Typical resolution engraving can be up to 8000 dpi, the interval between two consecutive elementary steps of etching is approximately 3 microns. Thus, in order to reproduce the engraving on the surface of the printing form, the printing form can be engraved with a laser beam based on the generated plan depths.

A significant advantage of this approach is that the various elements of the sketch, the components of the engraving on the printing form, the full sketch gravure printing, gravious not individually, but all at the same time, item by item. In addition, unlike the above approaches, the duration of the stages of engraving does not depend on the complexity of the sketch of the printing form, and depend only on the maximum depth of the engraving sketch. This p is the finite element method also gives more flexibility and control in relation to the profile of engraving and its shape.

Method of engraving, disclosed in International publication no WO 03/103962 A1, can be used, in particular, the technology of engraving particularly complex drawings gravure printing, as disclosed in International publication no WO 2005/090090 A1 and WO 2007/119203 A1, also on behalf of the Applicant of the present invention. Elemental principle of engraving, disclosed in WO 03/103962 A1, is the most suitable to create microrelease pattern, as discussed in International publication no WO 2007/119203 A1, and shows a high degree of complexity and density of elements in combination with an acceptably low time of engraving. Illustrative image of gravure printing shown in figures 1 and 2, and these images are similar to those that can be found on most banknotes, printed by intaglio. Figure 1 is a magnified image of the eye in the portrait, which can be found in International publication no WO 03/103962 A1 and figure 2 is an enlarged image of the eye is another portrait, according to the description of International publication no WO 2007/119203 A1, which is typical curvilinear image printed by the method of metallography, intertwined with microbubble, which is spatially modulated to form variations in tones. These are printed by the method of metallography images are usually formed from complex located the way spatially modulated curvilinear elements, forming a set of halftone graphic image that you want to create securities. Curvilinear elements usually have a line width of about 10 microns or more.

As discussed in International publication no WO 03/103962 A1, element-by-element method of engraving can be applied either to create a blank form for gravure printing, for example, polymeric forms, which is then used for the manufacture of any number of identical printed forms by electroplating duplication, either for direct engraving metal forms, which eventually will be used as forms for gravure printing, usually after plating the surface. Mainly, the etching process is carried out by fixing the laser engraving of the plate material at the circumference of the rotating cylinder and the moving block laser engraving in a direction parallel to the axis of the cylinder.

Laser engraving polymer blanks forms for gravure printing, as discussed in International publication no WO 03/103962 A1, was successfully put into production by the Applicant, which has now sold a number of Computer to an Intaglio Plate®machine, or CTiP® (Computers for forms of intaglio®), systems for printing banknotes worldwide. Such systems CTiP® is now used by a significant number of centres prepress p is gotowka for the production of banknotes around the world for the manufacture of forms for gravure printing, used to print banknotes and other securities.

Laser engraving polymer blanks forms for gravure printing, compared with the direct laser engraving of the printing form, has the advantage that the etching of the polymer workpiece can be performed in one pass and with high quality engraving. Engraving of polymer materials, respectively, is particularly suitable for the production of forms for gravure printing of high quality and high resolution, used for the manufacture of banknotes.

Another advantage of laser engraving polymer blanks forms for gravure printing is that these forms, once engraved, can be used for manufacturing, using galvanic technology, the so-called "Alto", which can be used for the manufacture of the primary (or original) of the printing form, which is used for replication of many identical forms for gravure printing, or the same as the original Alto for the direct production of many identical forms for gravure printing. Because galvanic technology is very stable and monotonous process, there is virtually no likelihood that there will be differences between multiple printed forms, which copiers who were from the same original. In addition, there may be used the same materials printed forms, which are traditionally used in the industry, without having any negative impact on the practical operation of the printer operating the printing machine.

However, direct laser engraving forms for gravure printing has the advantage in terms of requirements for the protection of the environment, as it allows not to use electroplating operations that make use of environmentally harmful chemicals.

Tests performed by the Applicant have demonstrated that the direct laser engraving of the plate materials, mainly metal materials, leads to the formation of waste that must be removed to ensure proper quality of engraving and printing. The amount of waste depends on the depth of etching and, therefore, increases with the depth of engraving. The amount of waste is particularly critical to remove them as soon as the need arises to perform relatively deep engraving in the material of the printing form, mainly engraving with a depth of more than 50 microns (and even more critical than 100 microns).

While the choice of material of the printing form affects the formation of the molten mix is s, this waste is inevitable in direct laser engraving forms for gravure printing, and you need to take action to remove these wastes, in order to avoid the deterioration of the specified quality engraving. This, again, is especially important in the case of etching deep drawings gravure printing, because produce large amounts of waste, to remove which becomes more difficult.

This is one of the reasons why Deinhammer 2006 proposed to perform an operation for pre-cleaning the surface of the mold for gravure printing, spraying pellets of solid carbon dioxide at low temperature (-80°C) on the surface of the mold and then subjecting the pre-treated printing plate chemical treatment in the acid solution. As already mentioned, these operations can potentially cause damage, as it may lead to uneven engraving. In addition, these clean-up operations can be performed only when the printing form is fully engraved.

It was also noted that, although the laser beam energy is well absorbed and converted into thermal energy in the first few micrometers of the material thickness of the engraving of the printing form as a result of local melting and evaporation of the material of thermal energy is no longer directed, and distributes the I deep into the material of the printing form evenly in all directions. As a result, a higher laser energy not only creates a deeper engraving, but also increases the width of the lines (see also Deinhammer 2004).

Thus, there is a need for an improved method and device for the manufacture of forms for gravure printing, in which a laser beam is used to etch the drawings gravure printing directly on the surface of the engraving laser, mainly metal, the material of the printing form.

The invention

The main objective of the invention to provide improved method and device for the manufacture of forms for gravure printing, for the manufacture of securities in which a laser beam is used to etch the pattern of gravure printing directly on the surface of the engraving laser plate material.

Another objective of the invention to provide such method and device, which improves the formation of the profile engraving drawings gravure printing, which you must engrave directly on the surface of the printing form.

Another objective of the invention to provide such method and device that allow you to limit the formation of molten waste and facilitate their removal and cleaning them, providing high quality engraving.

Another objective of the invention with the costs in creating solutions which allows the maximum extent possible to avoid the use of aggressive treatment technologies for the removal of the molten waste of the process of laser etching from the surface of the printing form, as these aggressive treatment technology can negatively affect the uniformity of etching and its quality.

These goals have been achieved thanks to the solution defined in the claims.

According to this invention, a method of making forms for gravure printing for producing securities, which use a laser beam to etch the pattern of gravure printing directly on the surface of the engraving laser plate material, mainly metal, and the laser engraving of the plate material layers perform in several distinct phases engraving, executed one after the other with accurate wiring so that the image of gravure printing gradually engraved on the surface of the plate material to the desired depth of etching, the surface of the material, engraved printing plate is cleaned from the waste of the process of laser engraving after each individual step of engraving and between these steps.

Also, an apparatus for direct laser engraving for implementing the above method, namely the laser device engraving, containing the reference element serving to fasten it material laser engraving of the printing form, block laser engraving, generating a laser beam, which is directed at the surface of the plate material in order to engrave the surface of the plate material in layers, in several separate stages of etching, and cleaning unit designed to clean the surface of the engraving of the plate material and remove it waste engraving process after each individual step of engraving and between these steps.

With this solution, the etching process is divided into many individual creating the microrelief of stages, each of which includes removing a limited amount of material from the surface of the printing plate and, accordingly, limits the generation of waste. In addition, the surface material of the engraving of the printing form is cleared after each individual step of etching so that the waste is removed before it will be executed the next stage of the etching, which ultimately improves the quality of the engraving.

According to a variant implementation of the invention, each separate stage etching leads to the selective removal of the layer of material from the surface of the printing form, the thickness of which does not exceed a preset max the maximum value. This predefined maximum value is preferably in the range of 10-15 microns.

According to another variant implementation of the invention, the cleaning of the surface material of the engraving of the printing form after each individual step of engraving and between these stages perform mechanical way, mainly with the help of rotating brushes which move over the surface of the engraving of the plate material after each individual step of engraving.

According to another variant implementation of the invention, the plate material set on the circumferential surface of the support cylinder, rotating in front of a movable block laser engraving, which generates a laser beam directed to the surface of the material of the printing form; when this unit laser engraving is arranged to move in a direction parallel to the axis of rotation of the support cylinder.

According to another variant implementation of the invention, the angle of incidence of the laser beam relative to the surface of the engraving of the plate material remain constant, thereby providing a perfect uniformity of the engraving during the entire process of engraving.

According to another variant implementation of the invention, the block laser engraving, generating a laser beam, which is directed to the surface the t of the plate material, moving on the surface of the plate material during each individual step of engraving from the initial position to the end position, and the cleaning of the surface material of the engraving of the printing form is performed in a time when the power of laser engraving, being idle is returned from the end position to the initial position.

Mainly in the context of a variant implementation of the invention in which the plate material is mounted on the circumferential surface of the support cylinder, as mentioned above, block laser engraving is moved during each individual step of engraving from the initial position to a final position step by step along the axis of rotation of the support cylinder with the processing software serial annular surface areas of the plate material, and the cleaning of the surface material of the engraving of the printing form is performed in a time when the power of laser engraving, being idle is returned from the end position to the initial position.

According to another variant implementation of the invention, etching the surface of the plate material begin with the deepest drawings gravure and gradually less deep drawings gravure during successive stages of engraving. It allows you to protect is from damage less deep and more subtle drawings gravure printing to complete the final stages of engraving, because less deep and more subtle drawings gravure printing more sensitive to clearance operations. This can be done using an automatic focusing device used to adjust the focus of the laser beam during different stages of etching, or by dividing the sequence of engraving in several phases, each of which includes one or more separate stages of etching, whereby during each phase of engraving engraved only part of the desired pattern of gravure printing.

The following are preferred embodiments of the invention, which form the essence of the claims.

Brief description of drawings

Other features and advantages of this invention will become clearer after reading the following detailed description of embodiments of the present invention, which are represented only in the form of Pogranichnaya examples and explained with the aid of the attached drawings, on which:

Figure 1 shows the magnified image of the eye in the portrait, made by the method of gravure printing, whose description can be found in International publication no WO 03/103962 A1;

Figure 2 shows an enlarged image of the eye on another portrait, made by the method of deep pécs is ti, according to the description of International publication no WO 2007/119203 A1;

Figure 3 illustrates a sample sketch of gravure printing for excise stamps or tape with logo, consisting of a set of structural elements that can be obtained direct laser engraving according to this invention;

Figure 4 depicts a grayscale photograph of a section of the form for gravure printing, engraved according to this invention; in the form of intaglio engraved multiple drawings gravure printing, shown in figure 3;

Figa and 5b depict two schematic illustration of a single phase etching and subsequent purification steps, in accordance with this invention;

6 depicts a schematic illustration showing a possible sequence of separate stages of engraving form for gravure printing according to the invention;

7 depicts a schematic illustration showing another possible sequence of separate stages of engraving form for gravure printing according to the invention;

Figa and 8b depict schematic illustrations showing another possible sequence of separate stages of engraving form for gravure printing according to the invention;

Fig.9 depicts a schematic side view of the laser device engraving done for the effect of the proposed method; and

Figure 10 depicts a schematic view of a perspective view of the laser engraving device depicted in Fig.9, which shows only part of the components of the device.

Detailed description of embodiments of the invention

In the context of this invention the concept of "sketches gravure printing or pictures of gravure printing" should be understood as a reference to the sketches and drawings that are produced by etching and which consist of an ordered set of curvilinear elements with varying line width and the depth of the engraving. Such sketches and drawings gravure produce characteristic of the printed image and images on printed materials that you can easily see and find on most securities. Examples of such designs and drawings, printed by intaglio shown in figures 1 and 2, which have already been discussed, as well as figure 3, which shows a sample sketch gravure printing, which may be engraved in the form of corresponding drawings gravure printing to form gravure printing by means of direct laser engraving according to this invention. These examples, of course, purely illustrative and should not be construed as limitations of the scope of this invention.

Sketches gravure printing and graphics obtained according to this invention, ledue is to be distinguished from sketches and drawings, used in the context of gravure printing (or gravure printing on rotary machines), where they simply consist of a matrix of many cells with varying width and/or depth, engraved on the surface of the cylinder and separated from each other by the walls of the cells. When gravure printing uses low-viscosity pastes, which can fill the cell above the walls of the cells so that individual cells are not visible in the print. Cells in the gravure printing typically have a depth of 50 microns (usually the depth of the cell is in the range of 10-30 microns), and gravure printing does not produce significant relief pattern on the printed final product. Detailed explanation of gravure printing can be found in "Handbook of Print Media" ("guidelines for print media") Helmut Kipphan, Springer-Verlag, 2001, ISBN 3-540-67326-1 (see for example, Chapter 1.3.2.2 on p.48-53, and Chapter 2.2 on SCR-394).

In contrast, gravure printing, used for fabrication of securities based on the use of engraved printing forms, in which the depth of the curved lines forming the drawings, at least some of them, usually greater than 50 microns. These drawings gravure printing, also covered with ink of high viscosity, and printing is performed under high pressure, resulting in the characteristic relief lettering printed on the final p is oducti.

Figure 3 shows a sample sketch gravure printing, indicated generally by the number 12 position, for excise stamps or tapes with emblems, which can be obtained direct laser engraving according to this invention. This sketch 12 gravure contains many structural elements 12A-12g, including, for example, so-called latent image 12A, texts or similar alphanumeric signs 12b, 12, 12d variable size, large surface figure 12E printed items gravure (not shown), logos 12f and figures 12g of blokeret. Can be provided, and any other drawings or combination thereof, including figures, such as those that can be found on a typical portraits made by intaglio, as shown in figures 1 and 2.

The various elements 12A-12g of illustration gravure printing, shown in figure 3, can be performed using appropriate software, such as software system ONE®, sold by the Applicant of this application. Profile of engraving each item 12A-12g can be determined individually in accordance with the parameters selected by the designer to create a so-called initial terms of the depths, as discussed in International publication no WO 03/103962 A1. This initial plan depth is then copied digitally so what about the times as you need to get the original terms of the depths of forms for gravure printing for engraving. Partial view of the surface of the mold 1 for gravure printing, which was engraved on the basis of the sketch gravure printing, is shown in figure 3, shown in grayscale pictures in figure 4. On halftone pictures in figure 4 actually shows the mirror image engraved form 1; this means that the drawings gravure printing, which is engraved on the printing form 1, are the mirror image of the sketch gravure printing, as shown in Fig 3.

The following describes, with reference to figa and 5b, the basic principle of the proposed method. On figa schematically shows the plate material 1 in the process of engraving the laser beam 2 to receive on its surface engraved 3. The shaded area on figa indicates the material that is removed by the laser beam 2. The size of the engravings 3 is increased for the purpose of illustration. For example, at least part of figure 3 gravure printing can be engraved with a depth of approximately 80 microns. It should be understood that the depth of the engravings can reach up to 150 (or eventually more) microns, while the typical line width is in the range of 10-500 microns. A wider range of the width of the lines or surfaces are possible under the conditions that the engravings of the formation is carried out corresponding to the printing elements, which prevent the removal of paint from the engraving in the operation of the system remove the residual ink in gravure printing presses.

The etching is preferably performed element-by-element on the basis of three-dimensional data about the image element of the plan depth of engraving for the given drawings gravure printing, as described in International publication no WO 03/103962 A1. The plate material 1 is preferably manufactured, or has an outer layer of metal, such as Nickel, steel, brass, zinc, or their alloys; all of these materials are widely used in printing technology.

According to this invention, the plate material 1 is engrave in several distinct phases engraving (figa illustrated the first of a series of separate stages engraving), performed one after the other so that the drawings intaglio engraved slowly and in layers on the surface of the plate material 1 to the required depth of the engraving. Preferably, each individual step of etching leads to the selective removal of the layer of material from the surface of the printing form 1, the thickness of which does not exceed a preset maximum value ΔMAX. This maximum value ΔMAXpreferably 10-15 microns.

As schematically shown in fig.5b, the surface of the material of the engraving printed Faure is s 1 are cleaned after each individual step of engraving, that is, after removal of each layer. Cleaning the surface of the material of the printing form 1 can be easily performed by mechanical means (i.e., without resorting to the use of aggressive cleaning methods). This treatment may preferably be performed using a rotating brush 9, which is moved over the surface of the engraving of the plate material 1.

As will be shown, the plate material 1 preferably can be mounted on the circumferential surface of the reference cylinder, which rotates in front of a movable block laser engraving, which generates a laser beam directed to the surface of the plate material 1, the block laser engraving is arranged to move parallel to the axis of rotation of the support cylinder. In this regard, can be easily performed every step in the engraving, while the power of the laser engraving is moved from the initial position to the final position, step by step, along the axis of the support cylinder, the processing of successive annular surface of the plate material, and the cleaning of the surface of the plate material 1 may be performed when the unit laser engraving, being idle is returned from the end position to the initial position.

Preferably, the angle of incidence of the laser beam 2 on the surface the material of the engraving of the printing form 1 was kept constant, that guarantees a perfect uniformity of etching during the process of engraving.

In the context of the present invention may provide a different sequence of the individual steps of engraving. Figure 6 illustrates a possible sequence in which the first and second images gravure printing, designated respectively by the numbers 3.1 and 3.2 positions, gradually form a layer-by-layer method. The first figure 3.1 gravure printing, for example, is engraved in three stages, with the formation of the first partial engraving during the first stage of etching, the deepening of engraving and obtaining the second partial engraving during the second stage etching, and, ultimately, getting the final figure 3.1 gravure printing in the third phase etching. Less deep figure 3.2 printing, similarly, engrave in two steps, which are performed simultaneously with the first and second partial engravings of the first figure 3.1 gravure printing, partial engraving obtained during the first stage, consistently deepens to the final figure 3.2 gravure printing during the second stage etching. The shaded areas of figure 6 similarly show a layer of material that is removed by the laser beam 2 during each phase etching (the same applies to Fig.7 and figa and 8b, which consider the next camping). In addition, it should be understood that the surface of the plate material 1 is peeled from the waste after each individual step of engraving.

7 illustrates another possible sequence in which the layer-by-layer etching of the surface of the plate material 1 start with the deepest drawings gravure printing, for example of figure 3.1, with a gradual transition to a less deep drawings gravure printing, for example for figure 3.2, then during successive stages of engraving receive figure 3.3 gravure printing. For example, during the first phase etching partially engraved only figure 3.1. During the second stage deepens the figure 3.1 and are formed simultaneously partial engraving of figure 3.2. In the third phase of figures 3.1 and 3.2 delve further, while on the surface of the plate material 1 is formed a third, smaller, figure 3.3 gravure printing.

As can be seen in Fig.7. in this case, during the second and third stages of etching, it is required to adjust the focus of the laser beam 2, as the material is removed at different levels of the plate material 1. This can be accomplished using a suitable device to adjust the focus of the laser beam 2 during the stages of engraving (this adjustment is the focus of the laser beam 2 was not a necessity and during the first phase etching).

Alternatively, as shown in figa and 8b, can be decomposed into a sequence of layer-by-layer etching on many phases of engraving, each of which includes one or more separate stages of etching, resulting in the course of each phase of engraving engraved only part of the set of drawings gravure printing.

On figa and 8b, for example, shows the case when the figure 3.1 gravure printing is formed during the first phase of engraving and figures 3.2 and 3.3 gravure printing are formed during the subsequent second phase etching. Or more precisely, figa and 8b shown to perform first, second, third and fourth stages of engraving (all of which correspond to the first phase etching) with the formation of figure 3.1, while smaller figures 3.2 and 3.3 form simultaneously during the fifth and sixth stages of engraving (fifth and sixth stages of engraving correspond to the second phase etching). Obviously that can be provided more than two phases engraving.

Unlike the previous stages of etching, illustrated in Fig.7, the focus of the laser beam 2 must not be adjusted during each stage of the etching, and just at the transition from one stage to the next, as in the case of a sequence of stages in the engraving, is illustrated in Fig.6.

<> The sequence of stages engraving discussed above with reference to Fig.7 and figa and 8b, can be effective in the formation of smaller and more delicate drawings gravure printing during the final stages of the engraving process and do not require re-clearance operations.

The sequence of stages engraving discussed above with reference to Fig.6, 7, 8A and 8b, are only examples of possible sequences of engraving. Can be provided by other stages of engraving.

Figure 9 schematically shows a partial side view of the laser engraving device for the implementation of the proposed method. As mentioned, the material 1 of the printing form is preferably mounted on a circumferential surface of the support cylinder 5 (see also figure 10), rotating in front of a movable block 4 engraving, which generates the laser beam 2 is directed to the surface of the material 1 of the printing form; block 4 laser engraving can be moved parallel to the axis Of rotation of the support cylinder 5.

The block 4 may be the appropriate unit for laser engraving of any type, for example ytterbium fiber laser. The laser beam may be supplied from a source of laser generator (not shown) to the laser head unit 4 through the fiber optic cable 40. Unit 4 caps is conducted on a frame (not shown in figure 10) and can be moved parallel to the axis Of rotation of the cylinder 5 between the initial position (shown in figure 10 left) and end position, indicated by the position 4* (in the right part of figure 10).

Unit 4 is arranged to move during each individual step of engraving from the initial position to the final position (e.g., from left to right in figure 10) step by step along the axis Of rotation of the support cylinder 5, by processing another annular surface areas of the plate material 1.

The cleaning unit, indicated generally by the number 6 position, preferably is mounted by a bracket (not shown) on the same frame as the block 4, move along with it. The bracket is made with the possibility of moving block 6 cleaning between the working position (as shown in Fig.9), in which the block 6 is introduced into contact with the surface of the plate material 1 is moved on the supporting cylinder 5, and a retracted non-working position (not shown), in which the block 6 is diverted from the surface of the plate material 1. Unit 6 cleaning preferably operates in a while block 4 laser engraving, being idle is returned from the end position to the initial position, for example, from right to left on figure 10. Can be provided, however, other structures for mounting block 6 cleaning, including structures in which the block 6 and block 4 are installed on separate frames, and/or structures in which the block 6 are the two which is retractable, for example, due to the rotation unit 6 in the direction to the surface of the material 1 is moved in the cylinder 5.

Unit 6 cleaning preferably is a rotary brush 9, which is designed to clean the surface of the plate material 1. Unit 6 mainly may also be provided with a suction head 10 for suction of waste that can be removed from the surface of the material of the printing form 1. In this example, a rotating brush 9 is located inside the suction head 10 so that the waste can easily be absorbed from all areas surrounding the rotating brush 9.

The rotational speed of the brush 9, the clamp brush 9 to the surface of the plate material 1 and/or the speed of movement of the block 6 purification parallel to the axis Of rotation of the support cylinder 5 are preferably adjustable to provide optimum cleaning performance.

Figure 9 and 10 of the plate material 1 is preferably engraved, being held on the supporting cylinder 5 in the same way as it is held on the circumferential surface of the plate cylinder gravure printing. This ensures that the profile of the engraving on the engravings remains essentially unchanged when the material 1 of the engraving of the printing form will eventually be installed in the machine gravure printing, which is more preferable in comparison with the solution disclosed in the international publication no WO 97/48555 A1, European patent application no EP 1334822 A2, International publication no WO 2006/045128 A1 or Deinhammer 2006, where the plate material 1 is to be engraved, being fixed on the plane. For completeness, disclosed gravure printing in the following European patent applications No. EP 0091709 A1, EP 0351366 A, EP 0406157 A, EP 0415881 A1, EP 0563007 A1, EP 0683123 A1, EP 0873866 A1, EP 1400353 A1, EP 1442878 A1, EP 1445098 A1, EP 1448393 A1 (WO 03/047862 A1), EP 1580015 A1, EP 1602482 A1, EP 1602483 A1, EP 1622769 A1 (WO 2004/101282 A1 and EP 1704052 A1 (WO 2005/077656 A1), all on behalf of the Applicant of this application.

Can be made of various modifications and/or improvements to the above described embodiment of the invention, without departing from the scope of the present invention, which is defined in the attached claims. For example, although the above embodiment of the laser engraving device includes a rotary support cylinder, a circumferential surface of which is mounted laser engraving of the plate material, the invention is equally applicable to printing systems having a flat table with a rectangular coordinate system X-Y.

1. A method of making forms for gravure printing, designed for the production of securities, including the use of a laser beam (2)generated by the unit (4) laser engraving machine for engraving pattern (3, 3.1, 3.2, 3.3) gravure printing directly to the and the surface of the plate material (1), made with engraving laser, wherein the laser engraving of the plate material (1) perform in layers in several distinct phases engraving, executed one after the other with accurate wiring so that the pattern (3, 3.1, 3.2, 3.3) gravure printing gradually engraved on the surface of the plate material (1) to the required depth of the engraving, the surface of the engraving of the plate material (1) is cleaned from the waste of the process of laser engraving after each individual step of engraving and between these stages, when the block (4) laser engraving is idling.

2. The method according to claim 1, in which each individual step of etching carry out selective removal of the layer of material with the plate material (1), the thickness of the specified layer does not exceed a preset maximum value.

3. The method according to claim 2, in which a predefined maximum value is from 10 to 15 microns.

4. The method according to any one of claims 1, 2 or 3, wherein at least part of the image of gravure printing engrave to a depth of at least 80 microns.

5. The method according to any one of claims 1 to 3, in which the cleaning of the surface of the engraving of the plate material (1) after each individual step of engraving and between these stages perform mechanically.

6. The method according to claim 5, in which the cleaning of the surface of the plate material (1) after each individual step of engraving and between these stages is carried out by means of the rotating brush (9), which move over the surface of the engraving of the plate material (1) after each individual step of engraving and between these steps.

7. The method according to any one of claims 1 to 3, in which each stage of the engraving represents elementwise engraving plate material (1) on the basis of three-dimensional data about the image element according to the plan of the depth of the engraving drawings gravure printing.

8. The method according to any one of claims 1 to 3, in which the laser beam (2)generated by the unit (4) laser engraving, send to the specified surface, and the block (4) laser engraving move during each individual step of engraving the surface of the plate material (1) from the initial position to the end position, and the cleaning of the surface of the engraving of the plate material (1) is performed in the time unit (4) laser engraving, being inactive, return from the end position to the initial position.

9. The method according to any one of claims 1 to 3, in which the plate material (1) installed on the circumferential surface of the support cylinder (5), which rotates in front of the moving block (4) laser engraving, while the laser beam (2), generiruemykh (4), send to a surface of the plate material (1), and block (4) laser engraving is arranged to move parallel to the axis (O) of rotation of the support cylinder (5), and this block (4) is moved during each individual step of engraving from the initial position to a final position step by step along an axis (O) of rotation of the support cylinder (5) with the processing software serial annular surface areas of the plate material (1), and cleaning the surface of the engraving of the plate material (1) is performed in the time unit (4) laser engraving, being inactive, return from the end position to the initial position.

10. The method according to any one of claims 1 to 3, wherein etching the surface of the plate material (1) begin with the deepest drawings gravure and gradually less deep drawings gravure during successive stages of engraving.

11. The method according to claim 10, in which the focusing of the laser beam (2) is adjusted during at least one of the separate stages of engraving.

12. The method according to claim 10, in which the focusing of the laser beam (2) do not regulate during different stages of etching, and engraving the surface of the plate material (1) is divided into many phases of engraving, each of which includes one and more separate stages of engraving, resulting during each phase of engraving engrave only part of a given figure (3.1, 3.2, 3.3) gravure printing.

13. The method according to any one of claims 1 to 3, in which the angle of incidence of the laser beam (2) relative to the surface of the plate material (1) remain constant during the entire process of engraving.

14. The method according to any one of claims 1 to 3, in which the plate material (1) is a metallic material.

15. The laser engraving device for the manufacture of forms for gravure printing, designed for the production of securities, containing supporting element (5), designed for the installation of the plate material (1)made with the possibility of engraving laser unit (4) laser engraving, generating a laser beam (2), which is directed at the surface of the plate material (1) to etch the pattern (3, 3.1, 3.2, 3.3) gravure printing directly on this surface layers in several distinct phases of engraving and block (6) cleaning, designed to clean the surface of the engraving of the plate material (1) and remove it waste engraving process after each individual step of engraving and between these stages, when the block (4) laser engraving is idling.

16. The device according to item 15, in which the block (4) laser engraving is configured to move the deposits during each individual step of engraving from the initial position to the end position on the surface of the plate material (1), the block (6) cleaning works in the while block (4) laser engraving, being idle is returned from the end position to the initial position.

17. The device according to item 15, in which the plate material (1) is installed on the circumferential surface of the reference cylinder (5), applicable as specified support element and rotating in front of the unit (4) laser engraving, which is arranged to move parallel to the axis (O) of rotation of the support cylinder (5).

18. The device according to 17, in which the block (4) laser engraving made with the possibility of movement during each individual step of engraving from the initial position to a final position step by step along an axis (O) of rotation of the support cylinder (5) with the processing software serial annular surface areas of the plate material (1)and block (6) cleaning works in the while block (4) laser engraving, being idle is returned from the end position to the initial position.

19. Device according to any one of p-18, in which the block (4) laser engraving and block (6) clean installed on a frame, is arranged to move relative to the surface of the plate material (1).

20. Device according to any one of p-18, in which the block (6) cleaning configured to perform the mechanical the Russian cleaning the surface of the engraving of the plate material (1) after each individual step of engraving and between these steps.

21. Device according to any one of p-18, in which the block (6) contains rotating cleaning brush (9), which can be put into contact with the surface of the engraving of the plate material (1) for the mechanical removal of waste from a given surface.

22. Device according to any one of p-18, in which the block (4) laser engraving is made to control for selective removal of the layer of material with the plate material (1) during each individual step of etching, the thickness of the specified layer does not exceed a preset maximum value.

23. The device according to item 22, in which a predefined maximum value is from 10 to 15 microns.

24. Device according to any one of p-18, in which the block (4) laser engraving made with the possibility of regulation to perform elementwise engraving plate material (1) on the basis of three-dimensional data about the image element according to the plan of the depth of the engraving drawings gravure printing.



 

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