EP1466726A1 - Process and device for engraving text and pictures on a printing cylinder by using an electronic engraving machine - Google Patents

Abstract

An electronic engraver operates a controlled, driven engraving system that handles line and vibration engraving so as to execute an engraving process on a printing cylinder. Text and image components for an engraving are each generated by different engraving processes. Line-engraving is used to engrave text and vibration-engraving to engrave images. An independent claim is also included for a device for engraving text and images on printing cylinders.

Description

The invention relates to a method for engraving texts and images on printing cylinders using an electronic Engraving machine and a device for Execution of such a procedure.

For the engraving of printing cylinders like those used in gravure printing two methods are generally used, namely the well-known vibration engraving and the well-known line engraving. With vibration engraving spatial, limited depressions are created, which in the subsequent printing process with Color can be filled and made from these for execution of the printing process is delivered. The playback of This gives details of the print with the vibration engraving limited that these wells or cells, which in a certain grid, the grid and thus the dimensions of the maximum possible cell per Specify area. So it can be between a rough grid can be decided which is a larger volume Color allows for the printing process, and a finer Grid, which has the advantage of increased detail reproduction has during printing.

Between the two extremes, namely a large volume for the printing ink and the greatest possible reproduction of detail was previously dependent on the print object weighed, which had the result that so far many times unsatisfactory printing results have been achieved.

This is essentially due to the fact that the Choice of a coarse grid when using vibration engraving, as I said, a large volume of wells or the well can be reached, but with the disadvantage of an unsatisfactory contour rendering the information to be engraved. When choosing one very fine grid when vibrating engraving can a very precise reproduction of the details of the engraving Information can be achieved, but with the disadvantage small volumes of the wells or cells. The The result is that the overall print density in these areas is not big enough. Therefore, the vibration engraving not used in all cases which both requirements must be met, i.e. size Volumes of the wells or cells in the case of very large ones Rendering accuracy of the details of a text or Silhouette.

For the reproduction of very fine details during printing the said line engraving is used for the engraving of the impression cylinder used. With the line engraving method the engraving tool, for example a stylus, is dependent on the engraving data based on the print data inserted at different depths in the impression cylinder, without the signal necessary for line engraving is superimposed by a signal that the vibration engraving performs. That is, only in those places of the impression cylinder on which to carry out an engraving process is the engraving element or the stylus in the The printing cylinder is immersed. There is a so-called support grid provided or to adhere to a spatial Separation of the depressions created by the line engraving leads, so that in the actual printing process later the squeegee also for reaching a defined volume enable during printing.

So far, the impression cylinders were either by the method the line engraving or engraved using the method of Vibration engraving, with each engraving process like this had been designed so that the largest possible print volume achieved with the greatest possible contour accuracy was, but always from the above Reasons had to lead to compromises with the result that certain printing results where there is a big Print volume and great detail reproduction could not be reached.

It is therefore an object of the present invention Method and device for engraving printing cylinders to create with both large print volumes as well as a great detail reproduction of the contours of Texts and images to be printed are achieved be, the classic engraving methods known per se to be used and a device to carry out an engraving of printing cylinders by means of known engraving devices operated or executed can be, so that the device essentially not about building in terms of Device complexity and operability compared to those of known devices for engraving Printing cylinders goes beyond, and thus the budget known devices at least not essential exceed.

The object is achieved according to the invention in view on the process in that both an engraving process using the line engraving method as well as an engraving method according to the method of vibration engraving for Execution of the engraving process of the impression cylinder used become.

The advantage of the method according to the invention lies in essential in that both engraving methods in the inventive methods are used in this way can that they have their respective advantages, namely great Contour accuracy and the creation of large printing ink volumes, can virtually unite, being for the execution of the method that provided for the overall engraving process Amount of data related to those to be printed Text and image information used almost simultaneously can be. Although the proposed according to the invention Procedure an increase in the size for the overall engraving process of the printing cylinder in time Measures greater than the time it takes to run either the vibration engraving would be required or for execution a line engraving, this time increase can but by increasing the speed of each Engraving methods according to the invention in a wide range be compensated.

According to an advantageous embodiment of the method becomes the text component of the engraving and the image component engraving with different engraving methods generated. In this way, the invention Overall procedures are operated so that for in each case different components of the Engraving, namely text engraving and image engraving, the most suitable method for each of these engravings is used.

According to another advantageous embodiment of the method is in the combined method according to the invention the line engraving for the engraving of the text and the Vibration engraving is used to engrave the images so that e.g. the line engraving only applies to those print data limited, which also increased as required Detail reproduction should do justice.

In yet another advantageous embodiment of the The data representing the texts is the procedure to carry out the line engraving and those representing the images Vibration engraving data generated as separate databases if For example, the basic data stock separated into image and text components is present. In the case of the separately available The image component is usually included with data a resolution of 120 to 200 lines per centimeter before, while the text component is several times higher Has resolution. In the case of separately available data one speaks of CT data (continuous tone) for image data and LW data (line work) for text data. Although the LW data in the case of a separate submission in a higher one Resolution will be available, this will be higher However, resolution for the engraving itself is not regular in previous engraving methods known in the prior art used. With the advantageous described above Design of the method according to the invention this disadvantage of the known engraving processes overcome.

In a preferred yet different embodiment of the The method according to the invention is a common one Texts and data representing the images to perform the engraving before, being used for execution the entire engraving, a data set for the Execution of the line engraving and a data set for the Vibration engraving can be separated. at the presence of a text and pictures representing each common database is called "All-in-CT data."

Since it is in the execution of the method according to the invention it is often not necessary to add the core component serious texts, i.e. of the individual letters, with the time-consuming line engraving process it can be extremely beneficial to perform the common one, representing the texts and images Generate the amount of data needed for engraving only the contours of the texts can be used should. The core part of the texts and the whole The image would then be part of the vibration engraving can be engraved, while only the one generated in this way Contour component of the texts or letters needs to be engraved with the line engraving, whereby for the execution of the overall engraving of the impression cylinder considerably by means of the method according to the invention Time can be saved.

After all, it is advantageous from the common that Data and text representing images (all-in-CT data) generate a subset of data with the least partly both positive and negative Writings of texts as well as at least partially pictures be engraved. Not only the contour, but the entire LW data is regenerated, in such a way that not only the contour is reproduced will, but these areas will be interconnected, so that in the LW database, as I said, both positive / negative fonts as well as areas, which are done with line engraving, whereas the remaining CT database with the usual Screening can be documented and with the vibration engraving is applied to the impression cylinder.

For certain applications, it may also be useful the text component by means of the method according to the invention the engraving at least in part through use using the method of vibration engraving, i.e. for certain parts of the the contours in their entirety, including the contours of texts or letters not separately with the Execute line engraving, but certain selected ones Areas of the texts only with the method of Engrave vibration engraving.

An apparatus for performing the above Process for engraving texts and images on printing cylinders using an electronic engraving machine is characterized in that the engraving system both close to the line engraving method as well Can be controlled and driven using the vibration engraving method is.

The advantage of the basic design of the invention Device is that only one Engraving system is provided that includes both the line engraving as well as vibration engraving. This Basic design of the device has the advantage that the basic principles of constructive design Such device compared to the previous one designed for line engraving and vibration engraving Devices of known type are used can, so that such a device inexpensive can be provided, even if the time required with which the overall engraving should be carried out on the basis of Use of an engraving system for both types of engraving is relatively high.

To make the engraving process faster and more suitable and adapted to those for line engraving on the one hand and the vibration engraving, on the other hand, has sufficient specifics To be able to better meet, it is advantageous to Advantageously to further develop the device according to the invention, that at least one engraving system for the Execution of the line engraving and at least one engraving system intended for the execution of the vibration engraving is. By means of an engraving system developed in this way can the engraving settings to the used engraving system or the engraving process be adjusted and criteria can be set, according to which the vibration or line engraving on the each best way can be set to play a data also changing in the best possible way Enable engraving information.

For example, according to the basic version of the invention Device only an engraving system for execution both the line engraving as well as the vibration engraving are provided, it can be advantageous that the engraving system for the execution of the line engraving and for the execution the vibration engraving can be controlled and driven sequentially is. For example, the vibration engraving first and then the line engraving or vice versa. But also sequential control and sequential Drive of a uniform single engraving system is possible, in which case the sequential Engraving by exchanging filter parameters with respect to the total engraving Data takes place, i.e. by filtering the The engraving system then performs data after performing the data the first type of engraving selected, the second type selected the engraving.

The invention is now based on the device described to carry out the method.

An electronic engraving machine, for example, is considered to be state of the art for the engraving of printing cylinders as they are made of DE-C-25 08 734 is known. The experts are such electronic engraving machines have long been known so that there is no detailed description here becomes. It should only be pointed out that the Device for engraving text or images on Printing cylinders using an electronic engraving machine So far at least one engraving system for execution the engraving included.

The tool with which the impression cylinder is used to execute its engraving is regularly a diamond, usually used to carry out the vibration engraving an angle of 120 to 130 degrees, based on a imagined solder on the surface of the engraving Printing cylinder has. With engraving systems, the one If the line is engraved, the angle can be chosen smaller as the stresses on the diamond due to the regularly lower number of punctures in the surface of the impression cylinder compared to those of the vibration engraving are reduced. The result is that in the case the line engraving of the diamond is regularly larger Has service life.

Usually the line depth is the engraving depth at max. 120 µm. In the later printing process with the invention engraved impression cylinders are said to the line engraving was used for the execution the contours of the text or the LW data absolutely comparable volumes as in the case of vibration engraving can be achieved. According to the invention the engraving depths in the order of 15 to 25 µm, it has been shown that despite this in any case for Engraving depth of the pure line engraving of low value sufficient due to the areal distribution Volume is achievable. This applies in particular to the Case of contour data generation and engraving with the help of line engraving, which is only partial information to those engraved by the vibration engraving Should add cells. For this reason, too a diamond with a relatively large one for line engraving 120 degree angles are used, i.e. the line engraving and the vibration engraving are done with the same Diamond operated. An exchange of diamonds between Both types of engraving are then no longer necessary. Depending on the type to be carried out later larger angles of pressure can be used, For example, a diamond angle of 130 or 140 degrees, if e.g. water colors are used for the printing process should. In this case, too, is the vibration engraving and line engraving with a single engraving system or feasible on a single diamond.

In the case of the provision of an engraving system Number of engraving systems, i.e. e.g. a Engraving system for vibration engraving and an engraving system for the line engraving, however, diamonds be used at different angles as they are previously standard for line engraving and the execution of the vibration engraving applied become.

If only one engraving system is used per engraving channel and the use of different diamonds with different angles or shapes or bringing one over the other (phase in) Engravings to each other. This can be done through the Engraving of individual cells is carried out, the spacing in to determine the two coordinate directions to each other are. This difference is an offset, i.e. a Mechanical displacement or a time delay Start the engraving in both coordinate directions. This offset can be used when using cylindrical Printing forms due to a spatial shift of the engraving system. Another realization the shift of the two engravings to each other the print form results, as I said, from the temporal Shift in the beginning of the engraving. A shift in the circumferential direction can be caused by a phase shift respectively.

Due to the data separation for the operation of the engraving system and performing various engraving processes, which of the best reproduction of the different Data can do justice with the engraving according to the embodiment of the method according to the invention and the device meets both requirements, namely a maximum achievable with the vibration engraving Volume and the possible with the line engraving high detail reproduction at least in the edge area of the Text dataset. So for the vibration engraving coarser grid are used and the demand for volume as large as possible. This is also from the point of view of the total engraving time to be spent important. Such a consideration is special in case of using two engravings in sequential execution important. By such Overall, the engraving time can be short being held. The resulting reduced engraving time is reduced the total time required for both engravings. Another measure to reduce engraving time can e.g. in the case of line engraving by increasing their Surface speed when operating the engraving unit when performing the line engraving.

When using existing or generated LW data or contour data, there are two options for use the line engraving. In addition to generating the contours of text data (outlining function) can be engraved Information in the resolution of the line engraving line spacing or nominal grid used lie. So the strength of the contour smoothing depends on the choice of line spacing or grid.

In the case of a vibration engraving, for example in grid 60 result from line engraving with a line spacing two additional engraving lines of 46 µm. The spatial resolution in the circumferential direction lies in the same order of magnitude so that the range between two Cup of the vibrating grid several ways of Filling allows so that the contour is closed Can take shape.

In the case of a line spacing of, for example, 33 μm the possibility of three more information in line form in the contour area a lettering in the edge area insert. The resolution in the circumferential direction is in this case so that in this case with a Vibration grid of 60 three engraving lines are possible. Through such a process, the open Marginal areas filled with small engravings.

In the case of such positioning of the marginal information by filling the open marginal areas Information generation for this line engraving accordingly be processed. The fillings of the border areas should not be those created by the vibration engraving Cut the well. For this reason, the information specially prepared for the line engraving. Here you can phase in or make a fixed assignment both engravings (via the sequential engraving) to each other an exact positioning of the line engravings in the Vibrations grid take place.

In general, the inventive method with the Overlay of the two engravings both for the case of the Circular mode as well as used for helix engraving become. However, in the case of helix engraving, this is increased Precise positioning required.

As a numerical example, 100% engraving time for one Engraving in grid 70 angle 4 with one engraving frequency assumed from 7.5 kHz. When changing from a 70s to a 60s grid is reduced in the case of vibration engraving 70% of the engraving time for vibration engraving the originally envisaged engraving time.

To ensure sufficient detail reproduction with the help of line engraving to achieve, e.g. a line spacing of equal or finer than 47 µm or e.g. in the order of magnitude of 50 µm can be selected. This corresponds to one Grid of 117 at angle 2 if the specified line spacing is taken as a basis. The corresponding engraving time for such a line engraving in the case of an elevated Surface speed of corresponding 25 kHz this corresponds to an engraving time of 41%. All in all this results in an engraving time of around 120% inclusive the procedure of the engraving system between linear and vibration engraving.

Is of a required line spacing of 33 µm for the line engraving runs out, then there is a total engraving time of 150%.

In the event of an increase in surface speed to a value which corresponds to an engraving frequency of Corresponds to 11 kHz, would be indicated for the two Cases result in an engraving time of 170% or 250%. Also with these increased engraving times, these are opposite the advantage of much better detail reproduction weigh.

The inventive method of data division and the separate feeding of the data to the two different ones Engraving process, namely vibration engraving and the line engraving, regardless of whether these now with a uniform for both types of engraving Engraving system can be carried out or in the device separate engraving systems are provided for each the method according to the invention can also be modified so that the line component created by a vibration engraving with a fine grid becomes. In any case, there is no compromise when choosing a grid between reaching a large volume and one increased detail reproduction more necessary because the inventive Procedure both criteria through each different (partial) processes.

Claims (11)

Process for engraving texts and images on printing cylinders using an electronic engraving machine, characterized in that both an engraving process using the line engraving method and an engraving process using the vibration engraving method are used to carry out the engraving process of the printing cylinder. Method according to Claim 1, characterized in that the text component of the engraving and the image component of the engraving are each produced using different engraving methods. Method according to one or both of claims 1 or 2, characterized in that the line engraving is used to engrave the texts and the vibration engraving is used to engrave the images. Method according to one or more of claims 1 to 3, characterized in that the data representing the texts for performing the line engraving and the data representing the images for performing the vibration engraving are generated as separate databases. Method according to one or more of claims 1 to 3, characterized in that there is a common data set representing the texts and the pictures for carrying out the engraving, with a total amount of data for the execution of the line engraving and a data set for the execution of the total engraving Vibration engraving can be separated. Method according to one or more of claims 1 to 5, characterized in that from the common database representing the texts and images, the amount of data is generated which is used to engrave the contours of the texts. Method according to claim 5, characterized in that a partial data set is generated from the common database representing the texts and images, with which at least partially both positive and negative fonts of texts and at least partially images are engraved. Method according to one or more of claims 1 to 7, characterized in that the text component of the engraving is carried out at least partially by using the method of vibration engraving. Device for engraving texts and images on printing cylinders by means of an electronic engraving machine, comprising an engraving system for carrying out the engraving, for carrying out the method according to one or more of claims 1 to 8, characterized in that the engraving system according to the method of line engraving as well can be controlled and driven by the method of vibration engraving. Apparatus according to claim 9, characterized in that at least one engraving system for performing the line engraving and at least one engraving system for performing the vibration engraving is provided. Device according to one or both of claims 9 or 10, characterized in that the engraving system for performing the line engraving and the engraving system for performing the vibration engraving can be controlled and driven in parallel or sequentially.