Method for manufacturing a printing form

FIELD: method for manufacturing "intaglio" deep printing forms.

SUBSTANCE: in accordance to the method, a laser is used to manufacture the form on basis of brass alloy and/or with external layer of brass alloy, with recesses and/or lines, where Vickers rigidity of the brass alloy exceeds 140.

EFFECT: form manufacture stages are shortened.

2 cl, 2 dwg

 

The invention relates to a method of manufacturing a printing plate for gravure printing "intaglio" (metallography).

In the manufacture of counterfeit documents, in particular banknotes, certificates, diplomas and the like, it is usual to have at least one stage of printing in gravure printing "intaglio", which operate with very high pressures. Therefore, the printing plate for gravure printing "intaglio" must withstand heavy loads.

In the known methods of manufacturing a printing plate for gravure printing "intaglio" exhibit (i.e. exposed to radiation) photopolymer plate with the exposed plate by electroforming to form a working matrix, and is already working with matrix electroforming form print form. The drawback of these methods lies in the fact that the production of printing forms is very time consuming. Another disadvantage is that when the electroformed or Department galvanically deposited layer defects often arise that require extensive retouching working matrix or printed form, and in some cases, the working matrix or printed form can be rejected. Another disadvantage is that the depth of the lines, depending, in particular, on the duration of exposure and the width of the Lin is th, cannot be chosen independently from each other.

In other known methods through the use of multiple exposure patterns in the multistage process of exposure you can achieve different depths of the lines. The drawback to this is that you cannot receive a passing depths lines and that these methods are particularly error-prone and time-consuming.

In DE 4430430 C1 disclosed a method of manufacturing an engraved rolls and plates for printing methods, according to which the metal base cause of the engraving layer, and after the engraving of the engraving layer on it put at least two layers of metal or compound of metal to increase the hardness and corrosion protection.

In EP 0103680 A2 uncovered the plate cylinder (shaft) gravure printing, consisting of a cylindrical core and placed on the pipe as a medium for engraving picture. The pipe consists of engraving machine by material which, in particular, on the one hand, provides the engraving without problems, but on the other hand, in accordance with high hardness also has a long service life. Imprinted picture vygravirovany mainly by electron-controlled engraving device with a diamond cutter. The galvanization process and the etching process in the case of such plate cylinder of the intaglio printing are unnecessary.

From GB 1044547 And the method for engraving printing forms by means of laser.

In DE 10134150 A1 discloses a method and device for execution by laser holes in printed form for gravure printing, mainly in the copper surface of the plate cylinder.

In WO 01/40272 A1 disclosed a method of manufacturing a raster of holes in printed form for gravure printing modulated by time of laser radiation, and this printed form is deleted auxiliary layer through which the laser radiation do raster fossa. Then remove this auxiliary layer is removed.

US 4301727 And refers to the printed form with a plastic core and a metal coating.

US 3556883 And discloses a method of polishing copper or copper alloys.

DE 4033230 A1 relates to a method for applying custom engraving for stamping on large metal pressure plate and/or an endless belt for surface treatment of a cloth or plates of plastic, wood, leather or other materials or pressed laminates for use in heating presses periodic or continuous action.

From DE 4212582 A1 is known a method for engraving printing forms, which consists of a copper engraving of the surface layer before etching provide mechanically stable protective layer is m, and then by e-beam fulfill located in the printed raster deepening.

The aim of the invention is to provide a method of the above kind, which would avoid the known disadvantages, took a little bit of time and would provide a high reliability and accuracy.

According to the invention this is achieved by using laser based brass alloy and/or the outer layer of brass alloy perform deepening and/or lines and that the hardness of the brass alloy Vickers choose more than 140.

It offers the advantage that the printed form has the required strength and durability can be enhanced, in particular, due to the chrome plating. In addition, by using a laser in the basis can be made small (thin) structure. The accuracy of these structures can be further improved through additional processing to remove the melting of burrs. Another advantage is that the depth of the lines can be chosen independently of each other, which increases the degree of protection is made via a printed form of the document.

In an improved embodiment of the invention can be provided that after the execution of the recesses and/or lines melting remove burrs. Due to this, the can is to significantly improve the accuracy of the lines and/or grooves, resulting in increased reproducibility of the printing form and its resolution.

In this regard, according to another variant embodiment of the invention, can be provided that the melting burrs are removed by further chemical processing (finishing), in particular in an acid bath, the electrolytic etc. With subsequent chemical treatment of the melting burrs can be removed simply and quickly and purposefully removed only the copper oxide or zinc oxide melting burrs, and not the base material.

According to another variant embodiment of the invention can be provided that the acid bath contains acetic acid, phosphoric acid and nitric acid, in particular about 40 vol.% acetic acid, 50% vol. phosphoric acid and 10% vol. nitric acid. In this composition the acid bath can be processed by immersion for a few minutes to get the mirror and smooth the surface of the base, and the other stages of further processing is not required.

In another embodiment of the invention can be provided that the depth of each of the recesses and/or each line or group of recesses and/or lines set independently from each other. Due to the different choice of the depth of the recesses and/or lines can be implemented more sometypes, making it possible to increase the degree of protection against forgery is made via a printed form of the document. In addition, in some other embodiments, execution of the printing form according to the invention is guaranteed that all the cavities and/or lines have essentially the same depth, making it possible to ensure a particularly uniform printed image (reprint).

According to another variant embodiment of the invention can be provided that is used as a base flat plate. The flat plate can be processed simply and quickly, allowing the required time of manufacture of the printing form can be maintained particularly short.

In this regard, in an improved embodiment of the invention can be provided that is connected with the laser engraving head and/or basis fixed by means of a carriage mounted for movement in at least two different and essentially parallel flat plate directions. Due to this engraving head and/or plate-base can move in the direction of the running lines and/or grooves. In addition, this motion can be further optimized with the possibility of achieving the shortest possible time the manufacture of printed forms and more low on the Lee passable, but not machined surfaces.

In another embodiment of the invention can be provided that the basis for the next step of the method homeroot. Due to the chrome plating can further increase the resistance of the printing form.

According to another variant embodiment of the invention can be provided that the emission of laser pulses are controlled by the control device. Using the control device is an easy way to control the proper execution of the recesses and/or lines, which makes possible direct "fine-tuning" nespasennyh laser pulses and increases the reliability of the method according to the invention.

The invention relates also to a printed form for gravure printing "intaglio" (metallography).

Such known printing plates consist of galvanically deposited and chrome-plated Nickel. The drawback to this is that the manufacture of these printed forms is very time consuming and requires a long nish and additional processing steps of printing forms, such as grinding, polishing, etc. and printed form because of defects is necessary in some cases to reject.

The aim of the invention is the creation of printing plates described above kind, which would not have the known disadvantages and which is what you would produce simply and quickly.

According to the invention this is achieved due to the fact that it contains the basis of brass alloy and/or the outer layer of brass alloy.

It offers the advantage that the printing plate has high strength, and durability can be enhanced, in particular, due to the chrome plating. In addition, by using a laser in the basis can be made small (thin) structure, and the accuracy of these structures can be further improved through further processing to remove the melting burrs.

In another embodiment of the invention can be provided that the recess and/or lines have a different depth, and the depth of these recesses and/or lines does not depend on the width of the recesses and/or lines, and can therefore be increased degree of protection against forgery of documents produced using the printing plate according to the invention. Due to the specified distribution of the depth of the recesses and/or lines can be used to implement additional protective feature.

According to another variant embodiment of the invention can be provided that the hardness of the brass alloy Vickers is more than 140. This ensures sufficient stability of the printing form according to the invention.

The invention will be further described in more detail with reference to the attached line and, depicting variations in its implementation.

The drawings show:

figure 1 - block diagram of the various methods of making printing plates for intaglio printing "intaglio";

figure 2 is printed by intaglio "intaglio" the site notes.

1 shows a block diagram of two well-known ways, and one variant of the method according to the invention of manufacturing the printing plate for gravure printing "intaglio". Numbers in circles indicate required for this stage is the time in days.

The assumption is made graphics 1, which can be represented, in particular, in electronic form in the form of a data file. In the case shown in the middle column of the way to step 6 first exhibit the film, essentially having a size made the basis on which some times is schedule 1. Then in step 7 exhibit photopolymer plate with this film as a template, and then with photopolymer plates on the next stage 15 by electrotype made a working matrix, defective places which retouch on stage 16. On stage 17 with a working matrix by electrotype made printed form, on which stage 18 retouch and phase 4 homeroot, resulting in getting ready printing plate 5. This method takes about 15 days.

In the beam shown in the left column known way on stage, 6 on the film exhibited only image graphics 1, which in step 7 is used as a template for exposing photopolymer plates. To get a working matrix, which repeatedly contains schedule 1, at the intermediate stages 8-15 first by forming 8 polymer, electrotype 9, further retouching 10 and re-electrotype 11 made creaser with one image, which after re-retouching 12 phase 13 TISNET several separate images on the stage 14 are in the whole image, which is at the stage 15 by electroplating to form a working matrix. Further, the manufacturing process of the finished printing form corresponds to the above-described method. At the same time to produce the finished printing form takes about 48 days.

On the plate cylinder for gravure printing "intaglio" set usually several, in particular three, printed form. For the manufacture of two other printed forms with working matrix requires approximately 9 days.

In accordance with the method according to the invention for manufacturing a printing plate for gravure printing "intaglio", an implementation option which is depicted in the right column of figure 1, with a laser in the base of the brass alloy perform deepening and/or lines. In other embodiments of the method according to the of the invention can be also provided the basis of a composite (multi-layered) material with an outer layer of brass alloy.

Brass called copper-zinc alloy containing at least 50% Cu. In addition to copper and zinc, it can still contain up to 3% lead. When alloying with other elements in addition to lead talk about special brass. Brass alloys in the sense of the invention can be brass and special brass.

It may be provided that information of a graphic file by computer controlled laser systems convert directly to control the laser team. Due to this, the production of printed forms can occur immediately after creating a graphic file, and essentially no additional intermediate steps.

In a preferred embodiment of the method in addition to the contour of the recesses and/or lines set the depth of the recesses and/or lines. This can occur separately for each of deepening and/or each line or collectively for a group of recesses and/or lines. While setting individual depths are not dependent on each other. Different depths can be achieved in the case of the method according to the invention in a simple manner by controlling the power of the laser beam or due to repeated passage of the laser.

In the case of traditional printed form, in the manufacture of which exhibit photopolymer plate and the like, the job is different the depths of the recesses and/or lines is impossible, because the depth is set at the stage of exposure. Due to the manufacturer, these printed forms broad lines have a greater depth than a thin line.

In contrast, in the method according to the invention the depth of the recesses and/or lines set regardless of their width. Can be provided by changing the depth of the individual lines on the contour and width of the line can remain the same.

As a laser can be used solid-state laser with basic fashion, preferably Nd:YAG laser with diode pumping.

Due to its profile of the laser beam cone penetrates into the surface of the material. In the marginal zone of the focused beam processes are melting as a result of which part of the material solidifies in the form of unwanted emissions and spray. The type and size of the regional emissions depend on the material power of the pulse and the depth of the engraving. Laser engraving metals, ceramics and some plastics, and the power density of the laser beam is so high that the material during processing within a few nanoseconds partially evaporates. In the material occurs colorless in itself, the recess - etching. Often the result of the interaction of molten core material with oxygen oxides, which is C their colour, do the engraving significantly eye-catching.

If used as a base flat plate, the recesses and/or lines can be carried out particularly quickly and simply, allowing the required time of manufacture can be maintained short. It may be provided that is connected with the laser engraving head and/or plate-based fixed by means of a carriage mounted for movement in at least two different and essentially parallel flat plate directions, which is implemented movable in the directions of x-engraving head and/or movable in the directions of the x-plate basis.

This makes it possible to move the laser beam from any point of the flat plate to freely definable another point along a freely definable curve, in particular direct. To set the original, in particular, the above graphic file, you can define the sequence of movements, guaranteeing a minimum time of manufacture of the printing form. While not required to complete the surface, in which lines and/or deepening should not be searched.

Engraving head can keep your optics or galvanically rejected mirror system (gallocanta). Especially high quality laser processing and short manufacturing time can be up to Tignale by combining these two optics. In other embodiments of the method according to the invention can be provided by several galvanically rejected mirror systems that are optimized for different widths of lines and ranges of depth. Using the engraving head in addition to bitmap 1 may be processed vector graphics 1, and, thus, can be selectively processed only those areas that contain the printed picture (reprint).

Figure 2 shows the banknote 20, having a section 21 gravure "intaglio". Usually there is a section 21 extends not across the banknote 20.

In other embodiments of the method according to the invention, the base may also be convex, in particular in the form of a cylinder, bucket cylinder, etc.

In the case of the method according to the invention the reliability and quality of the printing form during execution of the recesses and/or lines can be controlled in a simple way by means of the control device due to the fact that detected the emission of laser pulses. If the laser pulse is not emitted, the control unit gives a command for re-emission of a laser pulse, which reduces the risk of defective places.

The accuracy of the recesses and/or lines may be increased if you remove the casting burrs generated by the deepe the deposits and/or lines in the basis. These melting burrs consist essentially of oxidized base material, in particular of copper oxide or zinc oxide.

Removal melting burrs especially appropriate is the subsequent chemical treatment, which may include, in particular, the treatment in an acid bath, the electrolytic etc. you can guarantee that as a result of such subsequent chemical treatment removes the copper oxide or zinc oxide, and not brass alloy base.

Subsequent chemical processing can occur, in particular, by immersing the base in an acid bath, etc. containing phosphoric acid, acetic acid, nitric acid, arsenic acid, etc. or a combination of these acids. Particularly suitable is represented acidic bath containing acetic acid, phosphoric acid and nitric acid, and this acid bath may contain, in particular, about 40% vol. acetic acid, 50% vol. phosphoric acid and 10% vol. of nitric acid.

After execution of the recesses and/or lines and, if necessary, after removal of the melting of burrs can be provided for further retouching and/or control of the printing form in order to detect possible defects and fix them.

The service life of the printing plate can be further increased pic what edstam chrome framework at a later stage of the method.

The method according to the invention are produced printing plate for gravure printing "intaglio", contains the basis of brass alloy and/or composite material with an outer layer of brass alloy. It turned out that the brass alloy has a suitable strength to perform the printing plate for gravure printing "intaglio" and that using the laser in the basis can be made quite small (thin) structure.

In addition, formed by laser melting burrs can be simply and quickly removed from the base of the brass alloy by subsequent processing.

To ensure the appropriate strength of the printing form is good, if brass alloy has a Vickers hardness of more than 140.

Printing form according to the invention may have recesses and/or lines of different depths, and the depth of these recesses and/or lines can be set regardless of the width of the recesses and/or lines. Different depth of the recesses and/or lines may form a self-protective sign or may be part of another protective feature. This may be provided, in particular, the line is continuously changing depth.

When choosing a material for printed forms are of great importance to its mechanical properties, as gravure-printing "intaglio" re the OS paints happens mainly due to a very large pressure of the printing form to the imprinted material (paper or polymer). On an industrial scale it uses pressure up to 60 tons. To achieve a long service life of printing forms for gravure printing "intaglio" unsuitable materials with small hardness, for example copper.

Also of great importance to apply the material could be processed by the laser optimal "subtlety"and the spike can be removed more easily and, above all, selectively. Based on detailed research, for use in the method according to the invention are less suitable seem, therefore, also Nickel or steel. These materials subsequent chemical treatment always leads to the removal, though small, core material, which has a negative influence on the fineness of the lines.

It turned out that hardened variants brass meet all requirements in order to find use in gravure printing "intaglio" is protected from forgery.

1. A method of manufacturing a printing plate for gravure printing "intaglio", characterized in that the laser in the basis of brass alloy and/or the outer layer of brass alloy perform deepening and/or lines, and the hardness of the brass alloy Vickers choose the greater, h is m 140.

2. The method according to claim 1, wherein after execution of the recesses and/or lines melting remove burrs.

3. The method according to claim 2, characterized in that the melting burrs are removed by subsequent chemical treatment, in particular, in an acid bath, the electrolytic etc.

4. The method according to claim 3, characterized in that the acid bath contains acetic acid, phosphoric acid and nitric acid, in particular about 40 vol.% acetic acid, 50% vol. phosphoric acid and 10% vol. of nitric acid.

5. The method according to claims 1, 2, 3 or 4, characterized in that the depth of each of the recesses and/or each line or group of recesses and/or lines set independently from each other.

6. The method according to claims 1, 2, 3 or 4, characterized in that is used as a base flat plate.

7. The method according to claim 5, characterized in that is used as a base flat plate.

8. The method according to claim 6, characterized in that the laser is fixed by means of a carriage mounted for movement in at least two different and essentially parallel flat plate directions.

9. The method according to claim 7, characterized in that the laser is fixed by means of a carriage mounted for movement in at least two different and essentially parallel flat plate directions.

10. The method according to claims 1, 2, 3 or 4, trichosis fact, what is the basis for the next stage homeroot.

11. The method according to claim 5, characterized in that the basis for the next stage homeroot.

12. The method according to claim 6, characterized in that the basis for the next stage homeroot.

13. The method according to claim 7, 8 or 9, characterized in that the basis for the next stage homeroot.

14. The method according to claims 1, 2, 3 or 4, characterized in that the emission of laser pulses are controlled by the control device.

15. The method according to claim 5, characterized in that the emission of laser pulses are controlled by the control device.

16. The method according to claim 6, characterized in that the emission of laser pulses are controlled by the control device.

17. The method according to claims 7, 8, 9, 11 or 12, characterized in that the emission of laser pulses are controlled by the control device.

18. The method according to claim 10, characterized in that the emission of laser pulses are controlled by the control device.

19. The method according to item 13, characterized in that the emission of laser pulses are controlled by the control device.

20. Printing plate for gravure printing "intaglio", characterized in that it contains a base of brass alloy and/or the outer layer of brass alloy, the hardness of the brass alloy Vickers is more than 140.

21. Printing plate for gravure printing in aglio" according to claim 20, characterized in that it has recesses and/or lines of different depths, and the depth of these recesses and/or lines does not depend on the width of the recesses and/or lines.



 

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