EP1262315A1 - Method and apparatus for making a printing plate - Google Patents

Abstract

A relief pattern is produced in the surface (2) of a polymeric type form preform by material removal from the surface. Material is burnt away by irradiation along paths. Different depths of relief area(A,B,C) are produced along the same path by repeated irradiation along the path. An Independent claim is made for the process equipment which has a laser for irradiating a surface (2) of the preform (1) and a laser control unit. Data files contain commands for switching laser beams on and off along a path and each file allows time-displaced operation of beams.

Description

The invention relates to a method and an apparatus for manufacturing a printing form according to claims 1 and 21. In the printing form can it be z. B. a flexographic printing form or a rigid printing form act as letterpress or gravure forms, and the like.

It is already generally known to use a conventional CO ₂ laser to burn material directly out of a printing plate, which can be a polymer plate, for example, in order to produce a relief in this way in the printing plate in order to produce a flexographic printing plate. With this method, however, the CO ₂ laser is permanently power-modulated, so that the method is relatively slow.

Furthermore, it is already known from PCT / EP96 / 05277 for production a flexographic printing forme to use two laser beam sources the first laser beam source fine structures of a desired profile produce while deep with the second laser beam source Areas are created in the profile.

Fine and low-lying areas can be found at relatively high Working speed with the above two methods is not so easily manufacture. The pure power modulation is to this Purpose to be sluggish while using an acousto-optic modulator the laser power must be limited to relatively low values, so as not to destroy the modulator.

The invention has for its object a method for manufacturing to specify a printing form, in particular a flexographic printing form, with the very fine and deep structures quickly and easily have it made. In addition, a suitable for this purpose Device will be provided.

A procedural solution to the problem is in claim 1 specified. In contrast, there is a device-side solution to the posed Object in claim 21. Advantageous refinements of the invention are identified in the subordinate claims.

In a method according to the invention for producing a printing form, in particular a flexographic printing plate, is in the surface of a Printing blank a relief introduced that material of Printing blank is removed along traces by radiation, So by radiation that z. B. is turned on and off, for example by Modulators, e.g. B. acousto-optical modulators, light deflectors, such as movable Mirrors, etc. to change the intensity of the radiation. The removal occurs because along one and the same Track differently deep relief areas by accordingly frequent irradiation are generated. It can focus radiation be used or parallel radiation, provided they are for the named Purpose is intense or powerful enough.

According to the invention it is so that to form a relief in the Surface of the printing plate blank only relatively flat recesses can be obtained by irradiating the printing form blank once, during deep recesses by repeated irradiation the corresponding locations of the printing form blank are formed. This repeated irradiation of the printing form blank to produce the deeper one lying areas are staggered or successively so that a lower lying area can be obtained by repeated stripping becomes.

Because the lower lying areas of the relief structure by repeated irradiation can be worked out, the beam power can be relatively low be what brings with it that even very fast modulators on and off Switching off the beam power can be used in their Use the beam power just needs to be limited to that To protect modulators from destruction, such as acousto-optic modulators. According to the invention, it is thus possible to also be relatively fine and to be able to quickly develop deep structures at the same time to create reliefs to be able to manufacture with even better quality. This also applies in particular in view of the fact that between the individual burning processes the printing plate material when forming the deeper structural areas cools down again before it is removed again, which leads to that the printing form material does not heat up so much in these areas, so that the relief is extremely precise or true to form leaves. The material can be removed between the individual burning processes also be dissipated, e.g. B. be sucked off, which is a more accurate Working at the next removal process enables and better quality Structures leads.

According to one embodiment of the invention, the surface is irradiated of the blank with one and the same jet, which repeats is guided along a track. In this case there is only one radiation source required what construction and control of the appropriate device simplified and therefore cheaper. A track then has to be trained however, the beam traverses deeper areas several times be what increases the processing time. This disadvantage could be but are compensated for by the fact that several radiation sources for generation parallel rays are provided, each repeated be guided along one and the same track. The group of parallel Blasting could then block by block (in block mode) relative to Printing form blank to be moved to a group of additional tracks edit, etc. The areas or groups of tracks also be nested within each other to suppress block boundaries. Here, there are traces of another between the traces of a block Blocks.

According to one embodiment of the invention, the surface is irradiated of the printing form blank with several jets, one after the other be guided along one and the same track. One and the same track is processed one after the other with different beams. For this For example, the multiple beams can be juxtaposed in one direction be arranged lying, which runs transversely to the longitudinal direction of the track. After each lane crossing there is a relative shift between printing form blank and radiation group, so that now the same Track is processed by another beam of the beam group, etc.

In a further embodiment of the invention, the multiple beams can also be arranged side by side in a direction that in The longitudinal direction of the track runs. In this case too, an and processed the same track one after the other by different beams, where the time offset is the distance between the beams in the longitudinal direction corresponds to the track.

By using one and the same track using different Blasting can be edited, it is possible to have different depths To remove relief areas, for example, by jets of different powers or by rays of different wavelengths. To this In this way, printing forms with even better quality can be produced. So can, for example, be directly on the surface of the printing form blank ablate lying relief areas by rays, their performance less and / or its wavelength is shorter than that of those rays, which serve to remove deeper relief areas. In this way the surface-side border (pressure contour) of a trainee Create reliefs very precisely, what areas outside the Bordering is not absolutely necessary as it is not printed here becomes. These areas can therefore be more powerful and therefore faster be removed to accelerate the machining process.

Advantageously, the relief becomes material areas delimiting the surface of the printing form blank first removed in this way the relief contours at a relatively low temperature of the blank to be able to determine. Only then is the further removal of the Printing blank for the formation of the lower areas. At this The procedure is very precise on the surface side of the relief. In principle, however, the reverse procedure is also used possible that the surface-side borders of the relief be formed last.

According to an advantageous embodiment of the invention, the relief is on the surface side limiting material areas of the printing form blank in their spectral sensitivity to the wavelength of the abrading radiation adjusted, which affects the removal process of these material areas controls even better to get reliefs with even greater precision receive.

In a further embodiment of the invention, the irradiation of the Printing blank with laser radiation, because in this way the required Radiant energy can be easily provided. In this regard, focused laser radiation can be used.

To process the printing form blank along the tracks, the Beams or laser beams are moved relative to the printing form blank, or the procedure is such that the printing form blank is relatively stationary Blasting is moved. The jets and blank can also be used both and are moved relative to each other.

Here, for. B. uses a printing blank that has a printing surface has forming elastic material, such as polymer material, silicone or rubber. The printing surface could also be rigid, for example are made of metal.

For example, a plate-shaped printing form blank made of polymer material or other suitable elastic material on the surface of a rotatably mounted cylinder and firmly attached there are, for example by clamping, by suction using a vacuum, by Magnets, etc. To form a printing form blank, elastic can also be used or polymer material on the surface of a rotatably mounted Cylinders are drawn up or applied. This can be, for. B. are hoses that are pulled onto the cylinder, or it can liquid material or polymer material by doctor blade, spraying and Diving, etc., are applied.

According to a very advantageous development of the invention, the irradiation takes place of the printing form blank along a respective track depending of data files, one of which is one of the different ones Depth relief areas to be removed is assigned. The removal the material areas of the printing form blank are therefore purely digital controlled so that changes in radiation power are carried out very quickly can be what accelerates the machining process. The Data files can also be combined into an overall file that contains the data files as links in a chain, which are processed one after the other become.

According to an advantageous embodiment of the data files Invention produced as follows: Education and electronic storage of a basic two-dimensional relief pattern; Formation of one or more in different borders to the basic relief pattern for marking relief areas that increase with increasing Distance from the basic relief pattern should be lower; Drawing a track by the bordered basic relief pattern; Searching for limits of Relief basic pattern and the relief areas based on the borders on the track; and setting beam turn-on and turn-off commands based on the boundaries found and sorted into respective data files for the basic relief pattern and the lower-lying relief areas.

If the basic relief pattern is specified, for example by scanning a template or by graphic design from a designer on the screen of a computer, so with a given track width and Traces of the tracks relative to the basic relief pattern to be removed in the blank in different depths Create areas in a very simple way, in an automated way, which also speeds up the process.

The respective data files are used for modulation or for switching on / off of rays. For example, these could be Data files are used to control acousto-optical modulators, with the help of which the beams or laser beams are switched on and off become, and the functioning of which is generally known.

To let rays with different intensities pass through the acousto-optic modulators with different control voltages can be controlled. In this respect, the respective data files can be different Control voltages assigned to modulate the beams to be one of the respective when using a respective data file Use control voltages to control a modulator. The respective Control voltage is then in accordance with the data file connected. This switched control voltage then reaches the modulator.

An inventive device for producing a printing form, In particular, a flexographic printing form contains a holder for holding a Printing form blank; an optical device for irradiating a Surface of the printing form blank along a track by means of at least a beam to thereby ablate areas of the printing form blank; and a controller that uses a beam on and off commands contained data files corresponding intensity changes of the at least one ray on its way along the track controls. According to the invention, this device is characterized in that that the control device is designed so that it has several each Data files containing beam switch-on and switch-off commands (sample information) provides, each of which is used to process the blank serves along the entire track, and the time offset are workable.

Through this processing of the pattern information or The data files related to one and the same track can go along areas the track may be exposed to radiation one or more times, accordingly to get shallower or deeper areas along the track so that it is possible due to the quick controllability of the beam and the fact that this one on the same several times in succession Area of a track can be directed very short in the longitudinal direction and to create deep recesses in order to be very to obtain precise reliefs in the surface of a printing form blank.

According to one embodiment of the invention, the optical device formed so that it emits at least one beam, the Control device is designed such that a beam is one and the same Traces through and a new data file can be read out with each pass is. For example, if there is only one beam and there are three data files be processed to three depth levels in the surface of the To obtain printing form blanks, a respective track would have to be three times from Beam will be traversed.

But it is also possible to design the optical device so that it outputs several beams, each with only a separate data file are controllable. In this case, all rays would have to be on the same track go through one after the other.

For this purpose, the beams can be arranged side by side in one direction be transverse to the longitudinal direction of the track, so that by appropriate Shifting the beams in the transverse direction one after the other Cover with the track can be brought.

However, the rays can also lie side by side in one direction be arranged, which runs in the longitudinal direction of the track. In this case the beams are driven offset by the data files at a time interval, which corresponds to the distance of the beams in the longitudinal direction of the track.

Focused rays, such as focused rays, can be used as rays Laser beams.

Basically, the printing form blank can be a plate-shaped blank or be a cylindrical blank. At least he's at his Surface elastic and preferably consists of polymer material or at least contains one. But it can also be made of silicone, Rubber or other material, such as metal.

To process the printing form blank, this can be done in the form of a plate Training, for example, can be processed in a flat state if Beams guided along tracks and kept parallel to them at a distance become. Radiation sources and blank blank could then be in parallel planes are shifted relative to each other.

According to an advantageous embodiment of the invention, the printing form blank designed as a cylinder rotatably mounted about its longitudinal axis, which has an elastic material on its surface, for example polymer material, wearing. This can be plate-shaped and around its Surface. It is in the form of a plate on the cylinder surface attached, the plate can be removed from this after processing can also be removed to be used as a flat pressure plate become. The elastic or polymer material can also be firmly on the Surface of the cylindrical support remain after it is on it has been raised or applied in another form, such as by a Dipping, doctoring or spraying, and the like. In this case later the entire cylinder was used as a pressure cylinder.

When processing or irradiating the printing cylinder for generation the surface relief can be rotated while simultaneously a slidably arranged in the direction of the longitudinal axis of the cylinder Carriage is moved, the at least parts of the optical device wearing. This slide can be used, for example, to deflect mirrors of laser beams, or there can be laser beam sources directly on it be mounted. It is also possible to turn the cylinder around its longitudinal axis this also in the direction of its To move the longitudinal axis to the surface of the printing form blank to be able to edit fixed positioned optical equipment. This variant would be advantageous if the optical device itself from a Variety of radiation sources for generating a variety of rays exists and therefore a misalignment by vibrations is relatively large.

It has already been mentioned that for intensity control or power control, thus provided for switching the beams on and off modulators are that can be controlled via the data files. Here it can are preferably acousto-optical modulators that are very can be controlled quickly.

Each of the modulators is equipped with at least one analog switch connected, via which the modulator one of the pattern information appropriate control voltage can be supplied, the analog switch through which the data file can be switched. This makes a very precise digital Control of the processing beam or laser beam possible.

For example, according to an embodiment of the invention, a modulator be connected to the outputs of several analog switches, each by one of the several needed to engrave along a track Data files (pattern information) can be switched, the analog switch switch different control voltages. Depending on The data file and thus selected analog switch thus get another control voltage to the modulator corresponding to the pattern information, so that this one according to the selected control voltage Beam with greater or lesser intensity or power.

According to another embodiment of the invention, however, several can There are modulators, each of which is assigned an analog switch is, each by one of those for engraving along a track required multiple data files can be switched, the analog switch switch different control voltages.

Figur 1 das Prinzip der Erfindung bei der Bearbeitung eines Druckformrohlings zur Erzeugung eines Reliefs in seiner Oberfläche;

Figur 2 das Prinzip nach Figur 1 mit spektral angepaßter Oberfläche des Druckformrohlings;

Figur 3 ein Relief-Grundmuster mit Umrandungen zur Kennzeichnung von Reliefbereichen, die mit zunehmendem Abstand von Relief-Grundmuster tieferliegen sollen;

Figur 4 einen Schnitt entlang der Linie A-A von Figur 3 zur Erläuterung der Struktur eines fertigen Reliefs in der Oberfläche des Druckformrohlings; Figur 5 drei aus dem Relief-Grundmuster gemäß Figur 3 entlang der Linie A-A erzeugte Datenfiles;

Figur 6 eine Vorrichtung nach einem ersten Ausführungsbeispiel der Erfindung zur Herstellung einer Druckform;

Figur 7 den genauen Aufbau der Vorrichtung nach Figur 6;

Figur 8 eine Vorrichtung nach einem zweiten Ausführungsbeispiel der Erfindung zur Herstellung einer Druckform;

Figur 9 eine Vorrichtung nach einem dritten Ausführungsbeispiel der Erfindung zur Herstellung einer Druckform; und

Figur 10 eine Vorrichtung nach einem vierten Ausführungsbeispiel der Erfindung zur Herstellung einer Druckform.

The invention and exemplary embodiments are described in detail below with reference to the drawings. Show it:

Figure 1 shows the principle of the invention in the processing of a printing form blank to create a relief in its surface;

Figure 2 shows the principle of Figure 1 with a spectrally adjusted surface of the printing form blank;

FIG. 3 shows a basic relief pattern with borders for identifying relief regions which are to lie deeper with increasing distance from the basic relief pattern;

FIG. 4 shows a section along the line AA from FIG. 3 to explain the structure of a finished relief in the surface of the printing form blank; FIG. 5 three data files generated from the basic relief pattern according to FIG. 3 along the line AA;

Figure 6 shows a device according to a first embodiment of the invention for producing a printing form;

Figure 7 shows the exact structure of the device of Figure 6;

Figure 8 shows a device according to a second embodiment of the invention for producing a printing form;

FIG. 9 shows a device according to a third exemplary embodiment of the invention for producing a printing form; and

Figure 10 shows a device according to a fourth embodiment of the invention for producing a printing form.

The working principle on which the invention is based is described below With reference to Figure 1 described in more detail. In Figure 1 with the Reference numeral 1 denotes a printing blank, which is made of polymer material is made. To manufacture z. B. a flexographic printing plate becomes a relief engraved into a surface 2 of the printing form blank 1 by using Help from z. B. three focused laser beams 3, 4 and 5 polymer material the printing form blank 1 is burned away in some areas. It could more or less than three laser beams can also be used. To this For this purpose, the laser beams 3, 4 and 5 are sequentially along in time a track running on the surface 2 moves in the direction arrow 6 runs. The laser beam 3 is the leading laser beam and acts on the surface 2 of the printing form blank 1 first. Him follows along the same track and the laser beam 4, the in turn along the same track and again the laser beam is staggered in time 5 follows. Depending on the depth one in the surface 2 of the printing form blank 1 recess to be made in order to form the relief either only the laser beam 3, the laser beams 3 and 4 or all laser beams 3, 4 and 5 used. If the recess is to be relatively flat, only the laser beam 3 switched on, through which only a section A is burned away below the surface 2 of the printing form blank 1. The laser beams 4 and 5 are then not switched on. Are against it If deeper recesses are desired, laser beams 4 and 4 also come 5 used. Here again, the laser beam is used first 1 the upper section A of the printing form blank 1 burned away while a short time later the section lying below the bottom of section A. B is burned away using the laser beam 4. At even deeper Recess will be after using the laser beam 4 below the floor Section C of section B with the aid of the laser beam 5 burned away, etc. The laser beams 3, 4 and 5 thus create relief areas, in which relatively deep recesses are created should be irradiated several times in succession in order to be successive in time Steps the bottom of the first recess burn further away or dig.

The advantage of this principle is that it can be removed repeatedly the bottom of the same area with only one or more laser beams the beam power can be kept relatively low, what has the consequence that optical switching elements for switching on and off the laser beams can be used which is a relatively fast Have switching behavior, but are not loaded with too much power allowed to. This allows fine and very deep structures to be created at the same time generate, resulting in a significant quality improvement in manufacture of printing forms (printing plates, printing rollers, etc.) leads. As Switching elements of the type mentioned could be acousto-optical, for example Modulators are used, deflectors or beam deflectors, such as Mirrors, etc.

The printing form blank according to FIG. 1 can be, for example, one act as a plate-shaped blank that is processed in a flat state, or around a cylindrical printing form blank, for example on the Surface of a rotatably mounted cylinder lies and from this again is removable. The cylinder itself could also be used as a blank be referred to when it is on its surface, for example with polymer material would be coated.

The laser beams 3, 4 and 5 could have different powers according to an embodiment of the invention. The leading laser beam 3 could, for example, have a lower power than the two lagging laser beams 4 and 5, in order to be able to use the laser beam 3 to first of all better define the edges of the relief at a relatively low power. Lower-lying areas of recesses could then be burned away with the more powerful laser beams 4 and 5. For example, a CO ₂ laser beam with 100 watts could be used as laser beam 3, while the laser beams 4 and 5 are CO ₂ laser beams of 200 watts each.

The laser beams themselves are focused with the help of lenses 7, 8 and 9, which is why these lenses can be in the same plane, for example, however have different focal lengths, depending on the depth of the laser beam area to be burned. In Figure 1, the lens 7 has the shortest Focal length and the lens 9 the longest focal length. Naturally you could also use lenses with the same focal length in different Use layers if desired. With less accurate reliefs Lenses with approximately the same focal length at the same distance from the Printing blank 1 lie. It would also be possible to have different ones To use beam diameters for the individual laser beams 3, 4 and 5, if desired.

FIG. 2 shows a variant of the principle shown in FIG. 1. Here, an upper region 10 of the printing form blank 1 and the laser beam 3 for processing this upper region 10 are spectrally matched to one another. For this purpose, the surface of the printing form blank 1 is coated in the upper region 10 with a corresponding material which is particularly sensitive to the wavelength of the laser beam 3. The laser beam 3 can z. B. generated by a YAG laser whose wavelength is 1.060 microns. The beam itself can have an output of 50 to 100 watts. By means of such a laser, a beam waist in the focus of approximately 10 μm is obtained, so that extremely fine structures can be produced in the surface area of the printing form blank 1. For this purpose, the material in the area 10 must be selected so that it can be easily burned away by the laser beam 3. The remaining laser beams 4 and 5 can in turn be generated by CO ₂ lasers of 200 watts each in order to be able to burn away deeper regions at a distance from the relief edges. Not so high accuracy is required here, so that beam waists of 30 to 35 µm in the focus area can be accepted.

Figures 1 and 2 show how the relief structures socketed become. For this purpose, laser beams 3, 4 and 5 are turned on in track direction 6 different places in the track direction 6 switched off. It follows then a stair-shaped base course, the slope of the flanks corresponds approximately to the course of the focused laser radiation. The base flanks are designated in Figures 1 and 2 with 11, 12 and 13.

FIG. 3 shows a basic relief pattern 14 in the form of a uniformly blackened pattern Range. This basic relief pattern 14 represents the printing Area and must be on the circumferential side of lower lying areas 15, 16 and 17 be surrounded. The material of the printing form blank 1 must therefore be in areas 15, 16 and 17 are burned away. The resulting one Structure can be seen in Figure 4. This is a cross section along the line A-A in Figure 3.

The one shown in FIG. 3 is used to switch the laser beams on and off Relief basic pattern 14 used. On the screen of a computer the basic relief pattern can be shown first and in an electronic Memory can be cached. Then there are traces set on which the laser beams are guided when the relief is engraved. It is assumed that line A-A in Figure 3 is such a trace. The basic relief pattern 14 can be previously or then be provided with borders 18, 19, inside and outside to define the areas 15, 16, 17 in which the material of the Printing blank 1 to be burned away. At the intersections track A-A in FIG. 3 with the basic relief pattern or the borders 18, 19 are then on-off points for the laser beams, which, sorted according to the areas to be combined into data files.

For example, move along line A-A in Figure 3 in the direction of arrow 6, specifically with laser beams 3, 4 and 5 in FIG. 1, results the first intersection of track A-A with the basic relief pattern 14 one Switch-off point X3 for the laser beam 3, which is shown in Figure 5. The The intersection of the border 18 with the track A-A then results in a switch-off point X4 for the laser beam 4, during the intersection of the border 19 with the track A-A a switch-off point X5 for the laser beam 5 results. Points X4 and X5 are also shown in FIG. 5. With another Movement along the track A-A in Figure 3 in the direction of arrow 6 result turn on for the laser beams 3, 4 and 5 switch-on points, again switch-off points etc., so that finally the three shown in Figure 5 Data files D3, D4 and D5 for switching the laser beams on and off 3, 4 and 5 can be obtained.

The data files D3, D4 and D5 each have values "1" and "0" and serve for controlling acousto-optical modulators, which in turn are used for Switching the laser beams 3, 4 and 5 can be used. The beginning of a Track in Figure 5 at X = 0, so that the first time through the track using the Laser beam 3 burned the areas 17, 16 and 15 over the section A. until the laser beam 3 is switched off at X3. At the second time Passing through the track, the laser beam 4 is switched on at X = 0 and at X4 switched off, so that by the second laser beam 4, the section B is burned over the areas 17 and 16. At the third lane run if the laser beam 5 is switched on at X = 0 and switched off at X5, so that now only section 17 is burned away via section C. Seen from the location X = 0, the laser beam 3 is switched off at the latest, and the laser beam 5 earliest. After passing through the right branch of the basic relief pattern in FIG. 3 is then switched on again the laser beams 3, 4 and 5 in that order, etc.

The switch-on and switch-off points or data files can be made after production the borders 18 and 19 and defining the track A-A and the track direction generated automatically with the help of suitable computer programs become.

Figure 3 shows the structure of a device according to the invention Production of a printing form, such as a flexographic printing form.

The device includes a laser engraver with a machine bed 20. On the machine bed 20, the one to be engraved is here hollow-cylindrical trained printing blank 1 rotatably mounted. The Printing blank 1 on a central shaft 20a on the machine bed 20 provided bearings 20b is added. By means of a motor 21 the printing form blank 1 can be rotated about its central axis. On Encoder 22 or rotary pulse generator is used to generate pulses which correspond to the respective rotational position of the printing form blank 1. A carriage 23 is on guides 24 parallel to the axis of the printing form blank 1 moves. A screw 25 is used to drive this Carriage 23 along the guides 24, the screw 25 is rotated in one direction or the other via a drive 26 to take the carriage 23 accordingly.

A laser 27 is mounted on the carriage 23, which laser beam 28 emitted. The laser beam 28 is sealed off with the aid of a shutter 29, when it is not needed. The laser beam 28 passes through on and off Turn off a modulator 30 and is by a deflecting mirror 31 um z. B. deflected 90 ° and through a lens system 32 on the surface of the cylindrical printing blank 1 focused. With the help of the focused Laser beam 28 become the upper areas of the printing form blank 1 burned away in places to get into the surface of the blank 1 to engrave a relief. The cylindrical printing form blank also supports this a polymer coating on its surface so that after insertion a flexographic printing form is obtained.

A machine control 33 is provided to control the operation of the system, the control lines with the laser 27, the modulator 30, the rotary drive 26, the motor 21 and the rotary pulse generator 22 connected is.

6 also includes a CAD system 34, which is connected to a control computer 35, which in turn is used for control the machine control 33 is used.

With the help of the CAD system 34, a designer can view the associated screen design a pattern, such as the basic relief pattern shown in FIG 14. The designer can then use appropriate commands on the CAD system 34 borders 18 and 19 relative to the basic relief pattern 14 Define the areas in which the surface of the printing form blank 1 is to be removed outside the basic relief pattern. The designer can also determine the track A-A in Figure 3, along later the printing form blank 1 is to be engraved. The CAD system 34 calculates then the pattern information or data files shown in FIG. 5, where the number of data files corresponds to the number of areas that are removed should be. As already stated, this can be done using only one or more used in succession Laser beams are made. The sample information or data files D3 to D5 then become CAD system 34 to control computer 35 transferred and stored there, eventually to be processed to be fed to the machine control. This ensures the rotation the printing form blank 1 about its central axis, for the corresponding Displacement of the carriage 23 around the laser beam 28 the predetermined track on the surface of the printing form blank 1 lead, and for switching the laser beam 28 on and off in accordance with the data files D3 to D5 using the modulator 30, which is designed here as an acousto-optical modulator.

The internal structure of the machine control system is shown in more detail in FIG. Identical elements as in FIG. 6 are provided with the same reference symbols and will not be described again.

The machine control 33 contains a central control 36 as well several analog switches, in this case three analog switches 37, 38 and 39. Each of the analog switches 37 to 39 with the control input is on the output side of the modulator 30 in connection. In contrast, the analog switches receive 37 to 39 each have a different control voltage on the input side via lines 41, 42 and 43 from the central controller 36. Each after commissioning one of the analog switches 37 to 39, one arrives Control voltage of different sizes to the modulator 30, so that in Agreement with the selection of one of the analog switches 37 to 39 Intensity or power control of the laser beam 28 by the modulator 30 can be done. The selection or switching of each of the Analog switch 37 to 39 takes place via control lines 44, 45 and 46, via the central controller 36 each one of the data files D3, D4 and D5 sends to one of the analog switches 37, 38 and 39.

In the following it is assumed that the pattern according to FIG. 4 is along a circumferential line of the printing form blank 1 is to be engraved, and using only the single laser 27. In this case three rounds of the printing blank 1 required or three track runs. The first time the track is passed, the radiation intensity should be relatively low the surface area over section A in FIG. 4 be engraved. For this purpose the data file D3 succeeded at the control input of the analog switch 37, which is then in accordance with the data file D3 switches a relatively low voltage and this switched low Transmits voltage to the control input of the modulator 30. The next time the track is run, the data file D4 reaches the control input of the analog switch 38, which is now, for example, for removal of region B in Figure 4 has a higher voltage in accordance with the data file D4 switches and this higher voltage to the control input of the modulator 30 transmits, so that now the laser beam 28 with higher intensity reaches the surface of the printing form blank 1. In the third pass of the track, control is carried out using the Data files D5 at the control input of the third analog switch 39, the also switch a higher voltage to control the modulator can.

The above process can be for a next track in parallel can be repeated, etc. Of course, the above system can be repeated provide to shorten the engraving time. Every time the track is passed then the carriage 23 silent. Also an engraving along helical paths is possible, but you can also work in interlace mode, to avoid block boundaries.

Figure 8 shows a second embodiment of an inventive Laser processing system. The same elements as in FIGS. 6 and 7 are again provided with the same reference numerals not described again.

In deviation from the exemplary embodiment according to FIGS. 6 and 7 here on the carriage 23 three lasers 27a to 27c lying side by side available. Each of these lasers has its own shutter, its own modulator and assigned its own lens system. Each of the modulators 30a to 30c, which in turn are designed as acousto-optical modulators a separate analog switch is assigned in the machine control 33, which correspond to the analog switches 37 to 39 in FIG. 7. you will be also with the same or different input voltages supplied to provide focused laser radiation of different powers to be able to.

Will when rotating the cylindrical printing form blank 1 to its Longitudinal axis of the sled 23 simultaneously from right to left in FIG. 8 shifted, the focused laser beams 28a to 28c run up helical traces over the surface of the printing form blank 1. The focused laser beam 28a goes ahead and initially engraves Surface areas that correspond to areas A in Figure 4. Next, the focused laser beam 28b travels along it helical trace, engraving areas that match the areas B in Figure 4 correspond. Next, the same track will be focused Laser beam 28c swept to cover the areas along the track engrave that correspond to areas C in Figure 4. Here too the power of the focused laser beams in accordance with the Control the embodiment of Figure 7, for example, different high voltages at the control input of the acousto-optic modulators created and in accordance with the corresponding data files be switched. Block operation would also be possible here only cylindrical tracks can be traversed.

A third embodiment of the device according to the invention is shown in Figure 9. The same elements as in Figures 6 to 8 are again provided with the same reference number and will not be repeated described. In contrast to the exemplary embodiment according to FIG. 8 If the carriage 23 is fixed here, it is no longer in the longitudinal direction of the cylinder-shaped printing plate blank. Rather, the printing form blank 1 is now in its cylinder longitudinal direction slidably mounted, for which he is now arranged on the guides 24 is and z. B. is driven by means of the screw 25, the in turn rotated in one direction or the other by the rotary drive 26 becomes. This arrangement is advantageous if a large number of lasers are used at the same time Machining of the printing form blank 1 can be used, since this multitude of lasers is then no longer stable and low-vibration enough to be transported on a movable carriage.

A fourth exemplary embodiment of the system according to the invention is shown in FIG 10 shown. Here three focused laser beams 28a, 28b, 28c arrive at the same time in the circumferential direction of the cylindrical printing blank 1 running track. The focused laser beams 28a to 28c offset in this circumferential direction. Be generated by means of three lasers 27a, 27b and 27c, which are mounted on the slide 23 for example, are arranged one above the other and by three acousto-optical Modulators 30a to 30c are switchable or modulatable. The Focusing takes place with the aid of three lenses 32a to 32c, whereby for the the top and for the bottom beam deflection mirrors 31a and 31c are. Again, the control of the three laser beams could be done with the help of acousto-optic modulators 30a to 30c in accordance with the scheme shown in Figure 5.

Claims (36)

A method for producing a printing form, in which a relief is introduced into the surface of a printing form blank (1) by removing material from the printing form blank (1) along traces by radiation, characterized in that along one and the same track each lies at different depths Relief areas (A, B, C) are generated by correspondingly frequent irradiation. A method according to claim 1, characterized in that the irradiation is carried out with one and the same beam (3) which is repeatedly guided along a track. Method according to Claim 1, characterized in that the irradiation is carried out with a plurality of beams (3, 4, 5) which are guided in succession along the same track. A method according to claim 3, characterized in that the plurality of beams are arranged side by side in a direction which is transverse to the longitudinal direction of the track. Method according to Claim 3, characterized in that the plurality of beams are arranged side by side in a direction which runs in the longitudinal direction of the track. Method according to one of Claims 3 to 5, characterized in that relief regions (A, B, C) of different depths are removed by jets of different power. Method according to one of claims 3 to 6, characterized in that relief regions (A, B, C) lying at different depths are removed by beams of different wavelengths. Method according to Claim 6 or 7, characterized in that relief regions (A) lying directly on the surface (2) of the printing form blank (1) are removed by jets whose power is lower and / or whose wavelength is shorter than that of those jets which are used for Remove deeper relief areas (B, C). Method according to one of Claims 1 to 8, characterized in that material areas of the printing form blank delimiting the relief on the surface side are removed first. Method according to one of Claims 1 to 9, characterized in that the material regions (A) of the printing form blank (1) which delimit the surface on the surface are adapted in their spectral sensitivity to the wavelength of the abrading radiation. Method according to one of claims 1 to 10, characterized in that the irradiation of the printing form blank (1) with laser radiation, for. B. focused laser radiation. Method according to one of claims 1 to 11, characterized in that the jets are moved relative to the printing form blank (1). Method according to one of claims 1 to 11, characterized in that the printing form blank (1) is moved relative to stationary jets. Method according to one of claims 1 to 13, characterized in that a printing form blank comprising polymer material is irradiated. A method according to claim 14, characterized in that a plate-shaped printing form blank made of polymer material is placed on the surface of a rotatably mountable cylinder. A method according to claim 14, characterized in that polymer material is drawn or applied to the surface of a rotatably mountable cylinder to form a printing form blank (1). Method according to one of Claims 1 to 16, characterized in that the printing form blank (1) is irradiated along a respective track as a function of data files (D3, D4, D5), one of which is one of the relief areas to be removed at different depths (A, B, C) is assigned. Method according to Claim 17, characterized in that the data files (D3, D4, D5) are generated as follows: Formation and electronic storage of a two-dimensional relief basic pattern (14); Formation of one or more borders (18, 19) lying at different distances from the basic relief pattern for identifying relief regions (15, 16, 17) which are to be lower with increasing distance from the basic relief pattern (14); Drawing a track (AA) through the edged basic relief pattern (14); Searching for boundaries (X3, X4, X5) of the basic relief pattern (14) and the relief regions (15 to 17) on the basis of the borders on the track; and Defining beam switch-on and switch-off commands on the basis of the boundaries found and sorted into respective data files (D3, D4, D5) for the basic relief pattern (14) and the lower-lying relief areas (15 to 17). Method according to Claim 18, characterized in that the respective data files (D3 to D5) are used to modulate the beams. Method according to claim 19, characterized in that the respective data files (D3 to D5) are each assigned different control voltages for modulating the beams. Device for producing a printing form, with a holder for holding a printing form blank (1); an optical device (27) for irradiating a surface (2) of the printing form blank (1) along a track by means of at least one beam (28), in order to thereby remove areas of the printing form blank (1); and a control device using a beam and data files containing switch-off commands controls intensity changes of the at least one beam on its way along the track, characterized in that
the control device is designed in such a way that it provides a number of data files (D3 to D5) containing beam switch-on and switch-off commands, each of which is used to process the printing form blank (1) along the entire track, and which can be processed at different times. Apparatus according to claim 21, characterized in that the optical device is designed such that it outputs at least one beam (28a), and that the control device is designed such that a beam passes through the same track several times and a new one with each track run Data file (D3 to D5) can be read out. Apparatus according to claim 21, characterized in that the optical device is designed such that it outputs a plurality of beams (28a to 28c) which can be controlled by only one separate data file (D3 to D5). Apparatus according to claim 23, characterized in that the beams are arranged side by side in a direction which is transverse to the longitudinal direction of the track. Apparatus according to claim 23, characterized in that the beams are arranged side by side in a direction which runs in the longitudinal direction of the track. Device according to one of claims 21 to 25, characterized in that the beams are laser beams. Device according to one of claims 21 to 26, characterized in that the printing form blank (1) is designed as a cylinder rotatably mounted about its longitudinal axis, which on its surface is an elastic material, for. B. polymeric material. Apparatus according to claim 27, characterized in that there is a slide (23) which is displaceable in the direction of the longitudinal axis of the cylinder and carries at least parts of the optical device. Apparatus according to claim 27, characterized in that the cylinder is displaceable in the direction of its longitudinal axis and the optical device is firmly positioned. Device according to one of claims 21 to 29, characterized in that modulators (30) are provided for intensity control of the beams, which can be controlled at least indirectly via the data files (D3 to D5). Apparatus according to claim 30, characterized in that a respective modulator (30a to 30c) is connected to at least one analog switch (37 to 39), via which a control voltage can be supplied to the modulator, and that the analog switch through the data file (D3 to D5) is switchable. Apparatus according to claim 31, characterized in that a modulator (30) is connected to the outputs of a plurality of analog switches (37 to 39), each of which can be switched by one of the several data files (D3 to D5) required for engraving along a track, and in that the analog switches (37 to 39) each switch different control voltages (FIG. 7). Apparatus according to claim 31, characterized in that a plurality of modulators (30a to 30c) are present, each of which is assigned an analog switch (37 to 39), which can each be switched by one of the multiple data files (D3 to D5) required for engraving along a track and that the analog switches each switch different control voltages (Figures 8, 9, 10). Device according to one of claims 30 to 33, characterized in that the modulators (30; 30a to 30c) are acousto-optic modulators. Device according to one of claims 30 to 33, characterized in that the modulators are deflectors or beam deflectors. Device according to one of claims 21 to 35, characterized in that the beams are focused beams.

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