EP2523809A1

EP2523809A1 - Method and apparatus for optimizing the relative position of at least two printing-unit cylinders

Info

Publication number: EP2523809A1
Application number: EP11700822A
Authority: EP
Inventors: Björn Weidmann; Holger Delere
Original assignee: Windmoeller and Hoelscher KG
Current assignee: Windmoeller and Hoelscher KG
Priority date: 2010-01-14
Filing date: 2011-01-10
Publication date: 2012-11-21
Anticipated expiration: 2031-01-10
Also published as: DE102010000907B4; WO2011086044A1; DE102010000907A1; ES2601844T3; EP2523809B1

Abstract

The invention describes a method for optimizing the relative position of at least two printing-unit cylinders (21, 37, 40), in which method the relative position of the at least two printing-unit cylinders is set on the basis of measured values. The measured values comprise first values with respect to the size of the surface area (9), with which at least one of the printing-unit cylinders makes contact with a further body (5, 25, 40).

Description

Method and device for optimizing the relative position of at least two printing cylinder

The invention relates to a method according to the preamble of claim 1 and a device according to the preamble of claim 9.

Such methods and devices are used in printing machines and especially in flexographic printing presses for adjusting the distance of the cylinders involved in the printing process. Only when this distance is optimized, it comes to the order of a printed image, in which the ink transfer is in the desired range.

For this purpose, EP 1249346 A1 proposes to examine the printed image which is produced after the cylinders involved in the printing process are set against each other with an optical sensor. Based on the results, the employment is optimized. This procedure leads to good starting results. However, at the beginning of the printing process, images of inferior quality are often printed until the job is optimized.

To avoid waste, EP 1 916 102 A1 proposes measuring the topography of the printing form or of the printing cylinder with a laser or by mechanical scanning and thus obtaining values which are used in the printing press before starting the printing operation for adjusting the printing cylinder can. In this measurement of the surface of the printing plate cylinder, however, a number of factors that affect the transfer of color in the printing operation, are not taken into account. These factors include the behavior of the printing plate under the conditions prevailing in the printing gap and the Change almost all physical parameters of the pressure in the current printing operation.

In particular, in order to maintain a proper employment, it has been known for some time to monitor the pressure in the nip during the printing process. EP 0 867 281 A1 proposes this for a flexographic printing machine. However, it has been shown that due to dynamic changes of the printing plates even at a constant pressure in the nip to undesirable changes in the printed image can occur.

Therefore, the object of the present invention is to propose an apparatus and a method in which the optimization of the relative position of the at least two rollers involved in the printing process is more reliable than in the prior art.

For this purpose, the invention proceeds from the two last-mentioned publications, according to the teachings of which the optimization of the relative position - before and / or during the printing operation - is carried out on the basis of measured values.

The present invention achieves the object by recording measured values which comprise first values relative to the size of the surface with which at least one of the cylinders involved in the printing process touches another body. This may once be the absolute size of this area meant. Of this size, however, a share of a possible contact surface can be derived.

In this case, the present invention makes use of the fact that, in particular in the gravure or high-pressure processes, it depends on which components of the printing form touch the printing material in the printing nip. When high pressure printing the raised areas of the printing form during gravure printing in the engraved areas color transported and also transferred to the substrate.

As a result, it is important for the quality of the print image that all areas of the printing form to be printed also come into contact with the printing material. The same naturally also applies to a color transfer between cylinders upstream of the printing gap. In flexographic printing machines, this can be the transfer of ink from an anilox roll to the forme cylinder. Also In offset printing presses, ink and / or fountain solution is transferred between a number of rollers.

Therefore, in the present invention, the size of the areas in contact with another body is measured. This further body can be another printing cylinder, the color to be transferred. When the two printing couple cylinders are printing plate cylinders and impression cylinders, the printing material imparts contact. However, it is also possible to introduce as an additional body an additional measuring body, which is otherwise not involved in the printing process.

If such a further body has the same distance from a printing cylinder as the respective other of the at least two printing group cylinders, the optimization of the relative position of the two cylinders relative to one another can easily be carried out with the aid of the measured values of the further body. However, the further body can also be one of the at least two printing cylinder. If the at least two printing cylinders of the printing plate and the impression cylinder, so often touch these under the intermediary of the printing material. In particular, when the measurements are performed on the printing plate cylinder, the so-called area coverage, that is, the proportion of the print image is actually transferred to the substrate when the plate cylinder is in turn fully colored, by a measurement on the printing plate cylinder and not on the substrate such as for the teaching of EP 1249346 A1 be determined. This possibility is very advantageous, since the completeness of the image transfer is of course exactly the size that one intends to optimize by setting the relative position.

Another advantage is that, in addition to the first values for at least a first physical quantity, second values are also measured at a second size, which is not necessarily different. Thus, it is possible to measure the values of the size of the contact surface with a printing film having a plurality of pressure sensors, which can measure the contact pressure, which results in each case in a partial area of the surface. The second measured values can also be pressure values that manifest themselves, for example, in two exposed areas of the nip. It is also possible with a flexible printing plate print marks on the substrate aufzudrucken and to use the increase in area of the pressure point as a result of an increase of Anstelldruckes as a second value. Alternatively, the positions of the roller bearings could also be assigned as second values to the respectively determined first measured values. Also, a measurement of the position of the respective roll shell - which could be done for example with optical measuring means - appears advantageous. Importantly, in all of these methods, certain first values relating to the interface can be assigned to the relative position of the rollers or to pressure in the nip. Often the determination of the second values will be limited to the front end areas of the roller.

The determination of the second values in addition to the first values is particularly advantageous if the determination of the first values takes place in a device which is external to the actual printing unit and is often referred to as external stretching. In this case, it can be determined in the external horizontal bar at which relative position and / or at which adjusting pressure (second values) to another body a satisfactory positioning situation (first values) is achieved. The printing unit cylinder thus measured can then be positioned in the printing unit accordingly (that is to say corresponding to the second values with good first values) to the at least one other printing unit cylinder.

In this way one can save the certainly more expensive measuring devices for determining the first values in the printing unit. Measured values for carrying out the method according to the invention can also be obtained by recording electromagnetic radiation. Often you will record this radiation, which is reflected by the surface of one of the inking cylinder.

One way is to take advantage of the effect of frustrated total reflection. For this purpose, a light-conducting body can be brought to the printing cylinder. In a contact between a total reflecting surface of the light guide or radiation conductor and the surface of the printing cylinder, the effect of total reflection is usually weakened (especially if the surface is optically denser (higher refractive index) than the light guide and a diffuse reflection on the surface of the cylinder leads. In this case, the light is diffusely reflected back into the light guide, traverses it substantially transversely to its original propagation direction, therefore hits at an acute angle to the printing cylinder remote from the surface of the light guide and therefore occurs - for lack of total reflection because of the acute angle - from the light guide out.

If the light reflected in this way is recorded by a sensor which measures the intensity of the reflected light or of the electromagnetic radiation, for example, a measured variable is obtained that depends on the size of the contact surface.

To improve the effect and to avoid contamination of the light guide, a further foil-like body will be provided between the cylinder surface and the total reflecting surface of the light guide, which, inter alia, has an optical density which weakens the total reflection to a suitable extent. The film may be attached to the cylinder or preferably the total reflecting surface in a manner that allows for more intimate contact of the film with the total reflecting surface due to the pitch of the cylinder. When evaluating the first values (regardless of whether with pressure sensors, optically or otherwise as measured), a comparison can be made with absolute nominal values. However, a target image, in which the pressure-active components of the printing plate are distinguished from inactive, appears to be more advantageous especially with regard to a printing plate cylinder in high or low pressure. By comparing the measured contact image ("where does contact") with the target image also becomes clearer, where employment is still catching up.Another possibility, which shows good results especially in the high-pressure process flexographic printing, is the evaluation of the area increase: It has It has been shown that the area with which a flexographic printing plate transmits color increases sharply as a function of employment after reaching a first point of contact (often called the kiss-print point), and then saturates To bring about the relative position of the cylinders involved based on the course of the area increase:

For this purpose, an over-squeezing of the cylinder to be measured can be made to come in the saturation region. However, it is also possible to stop the setting process for a specific curve due to an analytical and / or empirical knowledge of the saturation behavior.

In this way, an optimized relative position of the at least two cylinders involved in the printing process can be assumed if the first values are at the setting of the at least one cylinder to the one further cylinder a desired value of a saturation point.

Which measured values are generated with the various devices and which measurements are thus based on the curves or graphs mentioned, will be further elaborated in the present description.

An apparatus for carrying out the method according to the invention has a measuring device with which the size of the surface, with which at least one printing cylinder cylinder touches a further body, can be measured.

As already mentioned, such a measuring device may comprise a foil which has pressure sensors each measuring the pressure in a surface section. If the resolution of this printing film is therefore sufficiently large-and thus the individual area sections are sufficiently small-even the contact of individual pressure points with the measuring device can be measured. If the number of pressure points coming into contact with the measuring device when the printing cylinder is set stagnates after a strong growth phase, the above-mentioned saturation approaches.

In a device utilizing frustrated total reflection and measuring the light intensity of the diffusely reflected radiation, the measured light intensity saturates when the contact surface between the cylinder and the measuring device does not grow as in the growth phase in the further employment. Further embodiments of the invention will become apparent from the description and the claims.

The individual figures show:

Fig. 1 shows an exemplary light intensity distribution, as they are for the

Camera 8 in Figure 2 results

Fig. 2 is a diagram of a device according to the invention with a

Light guide 5

Fig. 3 is a diagram of a second device according to the invention

Fig. 4 is a diagram of a third device according to the invention

Fig. 5 is a diagram of a fourth device according to the invention

6 shows the section A-A from FIG. 5

7 shows a view from FIG. 6

8 shows a diagram of a fifth device according to the invention

Fig. 9 is a diagram of a sixth device according to the invention

10 is a diagram of a device analogous to the third device according to the invention

Fig. 1 1 A scheme of an inking unit of a

Zentralzylinderflexodruckmaschine

Fig. 12 A printing plate cylinder with pressure sensors for determining second

values

13 is a sketch of a measuring roller 49th

Fig. 14 A temporal juxtaposition of measured values of the measuring roller

49

2 shows a device according to the invention, in which an optimized relative position between the at least two printing unit cylinders is found by the evaluation of electromagnetic radiation. This radiation is emitted by the radiation source 4. It enters the body 6 transparent to the radiation 6 at an angle which leads to a total reflection of the radiation 6 on the walls 7 of the body 5. The angle of incidence α of the radiation 6 on the walls 7 must move within a certain range in order to allow the total reflection. Another condition for total reflection is that the refractive index n1 of the body 5 is greater than the refractive index nO of the surrounding air. Due to these circumstances, the body 5 serves as the conductor of the radiation 6. In the case of light as a light guide.

The separators 1 1 space the film 3 on the body 5 and can 1 1 attach them to the film 5. The film has three important properties in this context and would be interchangeable with any material that also has these properties:

It has a certain flexibility compared to mechanical pressure. It can diffusely reflect the radiation 6 and has a higher refractive index n 2 than the body 5.

Also interesting are the flexibility, formability and depth of the unit Film Separators: Depending on the roughness and hardness of the roll to be measured, these can be adjusted. For example, if examining a printing plate cylinder with a flexible printing plate and a small distance between raised and lowered areas of the printing forme, a relatively hard "design" of the unit separators 1 1 / slide 3 and a small distance of the film 3 to the body 5 to If, on the other hand, the roller to be examined is an anilox roller 37 with a hard surface which has large distances between raised and lowered regions, then a relatively soft "design" of the unit is required for separators 1 1 / foil 3 and a small distance between the foil 3 recommended to the body 5.

If - as shown in Figure 2 - the grid point 2 is pressed in the direction of arrow 12 against the film 5, the film 3 gets in touch with the body 5. The total reflection is canceled in the area of the contact surface between the body 5 and film 7, the film is reflected the radiation diffuse back into the body 5. Those portions of the diffuse radiation 13, which incident on the wall 7 at a suitable acute angle ß, penetrate almost completely. As a result, the camera 8 registers an increase in light intensity, which is in proportion to the contact area between grid point 2 and body 5 (even if the film 3 mediates).

The camera (actually sensor for electromagnetic radiation) offers an image as sketched in FIG. 9 marks the contact surface of a grid point on the body. The camera gets a clear idea of the size of the touchpad. The contact surface 9 is located in the contact region 10, which is for example between two cylinders as a nip. The contact area 10 is thus the surface area in which contact between the cylinders could take place at all. The contact surface 9 is a partial region of the contact region 10 in which 9 actually takes contact.

If the transparent body 5 and the printing form carrier 1 are formed as cylinders rolling against each other, then different contact areas 10 \ 10 ^" are formed during the rolling process, which successively rush through the field of view of the camera 8. If the printing form carrier 1 carries an entire printed image, then the camera, the contact image of this printed image on the body 5 and the film 3 from successively recorded contact areas 10, 10 ^' , 10 ^" put together.

In the future contact areas 10 ^' , 10 ^" , the future contact areas 9 ^' and 9 ^{" are} sketched in FIG.

If the camera 8 records the intensity of the light remitted in the described manner from the film 3 due to the contact with the printing form, then the light intensity, as mentioned, is a measure for the contact surface. It can be measured for different zones of the contact area. Comparisons with absolute nominal values are possible. It is also possible to check how far the light intensity values in the whole contact area or, advantageously, in individual zones thereof are approaching a saturation point. Based on calculations and / or empirical values, it is possible to determine at which distance from this saturation point an optimized employment is achieved.

Figure 3 shows an alternative device. Again, electromagnetic radiation 6 is emitted from the radiation source 4. The angle γ under which the radiation 6 strikes the body 5 causes the radiation to penetrate largely into the body and only at the interface 17 (transition into an optically thinner medium) undergoes a total reflection when the body 5 is not -. as shown - in contact with the grid point 2. As a consequence of the total reflection at the interface 17, a very large part of the radiation 6 irradiated by the radiation source 4 arrives at the camera 8. If the grid point 2 - the here in contrast to Figure 2 a direct contact with the Body 5 has - in contact with the body 5, the total reflection is weakened because the grid point has a higher refractive index than the body. 5

As a result, diffuse reflection at the halftone dot 2 (diffusely reflected radiation 13) and transmission into the halftone dot (radiation 16) again occurs.

The contact through the grid point thus leads to a decrease in the light intensity to be measured by the camera. This decrease is a function of the contact surface 9 between grid point 2 and body 5. (This would also be the case if again a film with higher refractive index than the body 5 between body 5 and grid point 2)

FIG. 4 also shows a device in which the light source 4, transparent body 5, halftone dot 2 and camera 8 are arranged or shaped in such a way that as a result of contact between halftone dot 2 and body 5 and the concomitant weakening of the total reflection, a decrease in the distance from the camera 8 light intensity to be measured is reported. This is again a function of the contact surface 9 and can be used to measure the same.

Figures 5 to 7 show a device which operates according to the principle set out with reference to Figure 2. However, here the transparent body 5 is already designed as a transparent roller 25. The printing plate support 1 shown in FIG. 2 here is a printing plate cylinder 21. The roller arrangement of transparent roller 25 and pressure plate cylinder 21 can be made in the manner outlined in an external bar 22. As already mentioned above, such an arrangement can also be made in a printing unit. Then the transparent roller would either assign the further function of a roller normally arranged in the printing unit or the roller 25 would additionally be arranged in the relevant printing unit.

In both cases, the two rollers or cylinders 21, 25 to make against each other, which is sketched in Figure 5 by the arrow 26, which indicates the direction of movement of the roller block 18. This moves with the roller bearing 19 and the transparent roller 25 in the direction of the printing plate cylinder 21st This movement of the Bock 18 is usually expected with rail guides, linear motors or spindle drives on the base frame of the deck 23 are accomplished. The representation of all these individual components is not necessary in the present context. In all cases, it is now possible for the expert to monitor the position of the block 18 with position encoders as well as encoders (especially in the spindle drive). In this position or the positions of the two roller bearings 19 and 20 on the end faces of the transparent roller 25 may be second values within the meaning of the present document. Additionally or alternatively, it is possible to pressurize at least one of the two cylinders 21, 25 with pressure sensors. In this way, the resulting pressure in the nip can be measured and used as a second value. With regard to these second pressure values, it is also advantageous if at least two values are available from the region of an end face of the nip in each case. In this case, the extraction of the second measured values can also be limited to smaller partial areas or partial areas. In contrast, it is advantageous if the first values are obtained at least from the areas in which a contact between cylinders can take place (for example, in the case of a printing form cylinder size of the printing plate).

With the help of the usually easier to obtain second values, the relative position can then be found again, in which the first values to the size of the contact surface were in a desired range.

This is advantageous in particular when the first values for the contact surface in an external bar 22 are obtained and then only the same optimized setting situation as in the external bar 22 is to be found again in the printing unit.

FIG. 6 shows the transparent roller 25 from FIG. 5 once more in detail from the perspective of the arrows 29 along the section A-A:

Radiation carrier holders 24, which carry radiation sources 4, are attached to the end faces of the roller 25. The radiation sources 4 are positioned relative to the roller 5 such that the radiation remains in the transparent body analogous to that in FIG. 2, since it experiences a total reflection on its outer walls. However, the total reflection is inhibited when the film 3 is pressed by elements of the printing plate cylinder to the walls of the transparent roller. As a result, for the camera 8 within the roller 25, the contact surfaces 9 visible analogously to the situation shown in Figures 2 and 1. Rolling the rollers 25 and 21 against each other in their contact, it is possible to assemble different contact areas 10 and so to gain an impression of the color transfer of the entire printing plate of the printing plate cylinder 21 (ie the entire printed image of the printing unit). This possibility exists according to the present invention mind you, without having to apply color to the substrate and without that waste must be created by a pressure.

Of course, however, the teachings of the invention can also be applied to the simultaneous transfer of color, as will be shown later.

FIG. 7 shows the roller 25 from the perspective of the arrows 20, wherein among other things the roller bearing 19 'of the carrier of the radiation sources 24 and the foil 3 have been omitted for illustrative reasons.

Figure 8 corresponds largely to Figure 5, wherein the function of the transparent roller 25 is again perceived by a transparent body 5. In this radiation is irradiated by the radiation source 4. The transparent to this radiation body 5 can be made with the buck against the cylinder 21. The body in this case hangs on the bearing arm of the bracket 34 and can be moved along the rail 33 in the vertical direction, as indicated by the arrows 32. Body 5 and cylinder 21 can thus roll against each other (rotational movement of the cylinder is indicated by arrows 31). In this way, even with the device shown in Figure 8, a larger peripheral portion of the cylinder 21 can be brought into rolling contact with the body. On the representation of any actuators to the movement of the body 5 has been omitted.

In Figure 9, a device is sketched, which works on the optical principle as the device of Figure 3: touches the body 5, the cylinder 21 so comes through the weakening of the total reflection at the contact surfaces less radiation 6 at the camera 8.

The body 5 is made as shown in FIG. 9 like a punch along the rail 33 against the cylinder 21. By a plurality of such Anstellprozesse the entire surface of the cylinder 21, which can be successively rotated for this purpose by certain angles, scanned. FIG. 10 shows a device of a construction which is reminiscent of the beam path in FIG. Again, the light intensity decreases due to contact between body 5 and cylinder 21st If the body is moved by means of a rail 33 along the cylinder surface (represented by double arrow 35), again different contact areas 10 between body 5 and cylinder 21 can be swept over at different times.

In the figures, a variety of devices have been shown, in which a determination of the contact surface 9 was made by means of optical methods. If this undertaking is carried out with the aid of duck foil (pressure sensor in foil form), the printing foil takes the place of the surface of the body 5 or the roller 25, which touches the cylinder 21. One advantageous in part for the optical methods film 3 is not required to do so usually. Also, in this context, no description of a ray path or the like is required. Therefore, no additional figures need to be described at this point, which show a printing film instead of the described surface of the body 5 or the roller 25.

In Figure 11, two inking units 36 and 38 of a central cylinder flexographic printing machine with a central cylinder 40 are roughly sketched. These dyeing or printing units show how methods according to the invention can also be used. In a Zentralzylinderflexodruckmaschine of the type shown, a printing material 39 is fed to a central cylinder 40 and pressed there by means of a feed roller 41. The printing substrate 39 is transported by the rotation of the impression cylinder through nips 42, which the impression cylinder 40 with the printing plate cylinders 21 (called in flexographic printing forme cylinder) pronounced. In these nips he is 39 printed with the color of the respective printing unit, so that a multi-colored printing unit is created. There are now Zentralzylinderflexodruckmaschinen, which have a two-digit number of such inking units 36, 38. The direction of rotation of the cylinders 21, 40 and 37 is indicated by the arrows A, B and C.

The pressure in the flexographic printing process takes place here by the raised components of so-called clichés 45 - ie flexible printing forms - often as Raster points 2 are configured. The clichés are often colored by so-called anilox rollers 37 - ie also printing unit rollers in the sense of this document.

Further elements of the printing units such as doctoring chambers or roller blocks for adjusting the cylinder and roller 40, 21, 37 are not shown in FIG. 11. In FIG. 11, the impression cylinder 40 is equipped with a transparent body 5 and a camera 8. The transparent body 5 forms virtually a window in the lateral surface of the impression cylinder 40 (the impression cylinder is thus partially transparent). The camera 8 is rotated by the impression cylinder and in this way remains during the rotation of the impression cylinder 40 in a position in which it 8 diffuse radiation 13, which penetrates from the body 5 record. The operating principle of the measuring device 47 comprising camera 8 and body 5 in FIG. 11 corresponds to the functional principle which has already been explained with reference to FIGS. 3 and 5 to 7:

At at least one front end of the impression cylinder 40, radiation is emitted from radiation sources 4 into the transparent body 5 (eg shown in FIG. This is subject to a total reflection on the surfaces of the body 5, which is weakened when touches between parts of the cliché 45 and the body 5 come about. These contacts can also be mediated by a film 3. The printing material 39 can take the role of the film 3. It is advantageous to provide separators 1 1 between film 3 or printing material web 39 and body 5.

When the printing plate cylinders 21 are re-set using the measuring device 47 of the impression cylinder 40 (initial adjustment of the relative position between these two printing cylinder cylinders 40, 21) and the impression cylinder 40 transports stock 39 in this process, the production of waste paper is unlikely to occur be avoided.

However, it is possible that the measuring device 47 during a rotation of the impression cylinder data to the touch of the impression cylinder 40 with several or even all printing plate cylinders 21 wins. Thus, the relative positions can be optimized much faster than with positioning, the optimization of the relative positions at the beginning of printing Make inking unit 36, 38 for inking unit. Another advantage of the just described method is that it can do without second values in the sense of this document. Furthermore, a continuous dynamic monitoring of the contact surface 9 during the printing operation in the manner described appears particularly advantageous.

Another measuring device 48, which is shown in FIG. 11, consists of a cylinder 25, which is constructed analogously to the cylinder 25 in FIGS. 5 to 7. He 25 has a positioning device 43 which is articulated at the articulation point 44 fixed, for example, on the machine frame. The cylinder 25 can be made to the printing cylinder 21 and 37 of the inking units 36 and 38 and so measure the contact surface 9 (first values). FIG. 12 shows a printing plate cylinder 21, which is often used in the execution of the flexographic printing process. He 21 carries a flexible plate 45. In addition, the cylinder 21 shown in Figure 12 is provided with two pressure sensors 46, which are located in the vicinity of the front ends of the cylinder 21. These pressure sensors 46 can determine the contact pressure in the nip 42 and thus determine second values in the sense of this publication.

These can be used as follows:

With the measuring device 48 shown in FIG. 11, first values are obtained by the transparent roller 25 with the setting device 43 being set against the printing plate cylinder 21 located in the inking unit 38. For the optimized first values for the size of the contact area 9 between the cylinders 21 and 25, second (contact pressure) values are measured with the pressure sensors 46.

These are usually saved. They indicate at which pressure conditions (second values) at both ends of the nip there was an optimal area coverage, which was determined by means of the transparent roller. Before printing begins, the printing plate cylinder 21 is then turned against the impression cylinder 40. As a first approximation, it can be assumed that the same optimized area coverage is achieved at the same nip pressure values in the nip 42 (second values), so that a pressure is applied at the same nip pressure values can. Advantageously, however, one will introduce over the course of time correction factors for the print pressure, which take into account that the cylinders 25 and 40 have different diameters and that the printing material 39 has a certain elasticity.

In principle, a waste-free recovery pressure is possible with the method just described. Furthermore, it is possible to check the change in area coverage with the cylinder 25 from time to time, taking into account the contamination of the same 25 of course with color.

Instead of attaching the pressure sensors 46 in the execution of the described method to the printing plate cylinder 21, these 46 can also be attached to both the impression cylinder 40 and the transparent cylinder 25. This also applies to other means with which second values in the sense of this application can be obtained.

As already described, second values in the sense of the present document can also be obtained by position sensors which reproduce the position of the respective cylinder in its setting device 43. In particular, when using linear motors and the contact force can be measured. Since the cylinders are held by end-side bearings and these usually each have a setting device, it is advantageous to raise at least two second values to the Anstellsituation at each end face of the cylinder.

The method last described using the measuring device 48, which also uses second values, is also advantageous if the first values are obtained with an external bar 22.

Figures 13 and 14 illustrate once again the extraction of first and second measured values. FIG. 13 shows a measuring roller 49, which also has pressure sensors 46 for obtaining second values. The pressure sensors shown here cover a rectangular measuring range. It is expedient if these pressure sensors can continuously measure a certain increase in pressure so that it can be precisely assigned at which pressures at both end faces of the roller 49 which first values have resulted. In the middle region in the axial direction of the roller is the measuring range 50 for the first measured values. It is useful to subdivide it 50 into sections 51.

If this measuring area 50 is represented by a printing foil, the size of the subareas 51 often results from the resolution of the printing foil (resolution = in which area units pressure can be measured). For many of these slides, it is only possible to provide binary information about the prevailing pressure (if a certain pressure threshold is exceeded or not). However, the use of such a film may be sufficient.

It is also possible to make the measuring area 50 of the measuring roller 49 essentially as the aforementioned light-conducting body 5 or as the transparent roller 25. Also in this case, portions 51 of the measuring range 50 can be formed. This can be done, inter alia, by assigning the camera 8, the light emerging from the light guide 5 or the transparent roller 25 radiation to the subregions. For this purpose, the camera 8 may inter alia consist of a diode array which is mounted very close to the light guide.

FIG. 14 shows a juxtaposition of measured values of the measuring roller 49, which results in a time period T, while the measuring roller 49 is set against a plate roller 21.

In the illustrated period T, the cliché 45 is just starting to unroll on the measuring roller. The contact area, that is, the total area in which contact between the measuring roller and the cliché is possible, is - for illustrative reasons - outlined by the rectangles 45 ', 45 "and 45"'. At the beginning of the period T (top), no contact (rectangle 45 ') is present at all and no first measured values in the partial regions 51 of the measuring region 50 are determined. Only the pressure sensors 46, which have sensors which are raised above the surface of the roller 49, are already in contact with the plate roller 21 and each deliver a measured value 46 '(the measured values of the two sensors 46 recorded at one time are often different To set an optimized roll position, it may even be necessary to set different measured values at the two ends. After another rotation of the roller has due to further employment of the rollers 21, 49 A contact surface 9 is formed in a partial region 51 of the measuring region 50 which lies within the possible contact surface 49 ", which is illustrated as a black square in a partial region 51. In this way it is made clear that in this partial region a contact of the cylinders 21, 49 has taken place with a certain intensity If, for example, simple printing foils are used to determine the second values, then the associated statement that a contact with a certain minimum pressure has occurred in a certain subarea.

At the time the contact surface 9 is received, the pressure sensors 46 also report changed second pressure values 46 ", which are characteristic of the relative position of the rollers 21, 49 with respect to one another at that time, The above first and second 46" values thus form a pair of values the area coverage of a pressure at a certain relative position of the rollers can characterize each other.

After a further roll revolution - and the associated additional employment of the rollers 21, 49 against each other - four contact surfaces 9 have already formed within the possible contact surface 45 "'.

As already mentioned, it is u. a. possible to determine the optimized roller position by the rollers 21, 49 are employed against each other,

until a desired area (eg, partial areas 51 of the measuring area 50 which report contact) is reached and / or

- Until the contact surfaces 9 constitutes a certain proportion of the possible contact area and / or

- Until the contact surface 9 in its extension and shape corresponds to a desired image and / or

- Until the increase in contact surface 9, which results in a further employment of the rollers against each other, shows a saturation behavior or shows a certain (often empirically or analytically determined) behavior that promises rapid saturation ("curve").

In particular, the alternative listed in the last preceding indent can be implemented particularly well with the disclosed in this document optical methods. Here is the course of the camera 8 recorded light intensity as a function of the second values such as roll adjustment or pressure in the nip (at which the sensors 46 provide meaningful values) are recorded. In this case, the light intensity profile in the entire measuring range for the first measured values and / or the light intensity profile in a possible contact region 19 and / or the light intensity profile in partial regions 51 can be used to find the optimized relative position.

LIST OF REFERENCE NUMBERS

Printing plate carrier

dot

foil

Source of electromagnetic radiation (eg of light)

Transparent body / optical fiber

Wave field (usually electromagnetic waves)

Total reflecting surface of the body 5

camera

Touchpad

contact area

separators

Arrow in the "pressing direction" of the raster point 2 in FIG. 2

Diffuse radiation (backscatter)

Measuring range of the camera 8

Serrations of the body 5

radiation

Total reflecting surface of the body 5 (FIG. 3)

roller block

Roller bearing transparent roller 25

Roller bearing pressure plate cylinder 21

Plate cylinder

horizontal bar

Basic frame of the deck

Carrier of the radiation sources

Transparent roller

Arrow in the direction of movement of the roller block 18

Arrow in the direction of rotation of the roller 21

Arrow in the direction of rotation of the roller 25

Arrow in the direction of the figure 6

Arrow in the direction of the figure 7

Arrow in the direction of rotation of the roller 32 arrow in the direction of movement of the body 5

33 rail

34 bearing arm

35 double arrow figure 10

36 printing unit / inking unit

37 Anilox roller

38 printing unit / inking unit

39 substrate web

40 nip

41 application roller

42 nip

43 Adjustment device

44 articulation point of the adjusting device

45 cliché

46 Pressure sensor for determining second values

47 measuring device

48 measuring device

49 measuring roller

50 measuring range for first values

51 subregions of the measuring range 50 for first values

52

A, B, C arrow in the direction of movement of a cylinder

α acute angle, suitable for total reflection

ß Dull angle, radiation penetrates surface 7

Entry angle of the radiation into the body 5

Ί

t time

T period

45 ', 45 ", 45"' Possible contact area measuring roller / cliché

46 ', 46 ", 46"' measured values of the pressure sensors 46

50 'Timing of the Measured Values 51'

51 'measured values in the subareas

Claims

claims

Method for optimizing the relative position of at least two printing group cylinders (21, 37, 40), in which the relative position of the at least two printing group cylinders is adjusted on the basis of measured values,

characterized in that

the measured values comprise first values relative to the size of the surface (9) with which at least one of the printing-cylinder cylinders contacts a further body (5, 25, 40).

Method according to claim 1,

characterized in that

the measured values comprise second values for at least one second physical variable such as contact pressure between the printing unit cylinders (21, 37, 40) and / or relative position of the printing cylinder bearings.

Method according to one of the preceding claims,

characterized in that

the first values in turn comprise pressure values which denote the pressure which, upon contact of at least one printing cylinder (21, 37, 40) with the at least one further body (5, 25, 40) in area units of the possible contact area (10) between the at least one printing cylinder (21, 37, 40) and the at least one further body (5, 25, 40) builds up.

Method according to one of the preceding claims,

characterized in that

the first values in turn comprise measured values which are obtained on the basis of the recording of electromagnetic radiation (6, 13).

Method according to the preceding claim,

characterized in that

the electromagnetic radiation (6, 13) from the printing form (1, 45), the ink transfer surface of a printing cylinder (21, 37, 40) or a body, the the printing form or the ink transfer surface of a participating in the printing process cylinder (21, 37, 40) is touched (3, 39), is reflected, before the recording of the radiation takes place.

Method according to one of the preceding claims,

characterized in that

electromagnetic radiation (6, 13) is recorded, the (6, 13) was previously coupled out due to frustrated total reflection from a radiation conductor (5, 25).

Method according to one of the preceding claims,

characterized in that

an optimized relative position of the at least two printing plate cylinders (21, 37, 40) is assumed when the first values in the employment of the at least one printing plate cylinder (21, 37, 40) to the one further body (5, 25, 40) has a nominal value of a saturation point away.

Device for optimizing the relative position of at least two printing group cylinders (21, 37, 40), with which an optimized relative position of the at least two on the printing unit cylinder (21, 37, 40) can be determined on the basis of measured values,

marked by

a measuring device (47, 48) with which the size of the surface, with which at least one printing cylinder (21, 37, 40) has a further body (5, 25, 40) touched, measurable.

9. Device according to the preceding claim,

characterized in that

the measuring device is mounted in or on the at least one printing unit cylinder (21, 37, 40) and / or in or on the one further body (5, 25).

10. Device according to one of the preceding claims,

characterized in that

the measuring device comprises a pressure measuring unit with which the pressure distribution arising in at least part of the contact surface between the printing cylinder and the further body can be measured.

1 1. Device according to one of the preceding claims,

characterized in that

the measuring device comprises sensors (8) for recording electromagnetic radiation (6, 13).

12. Device according to one of the preceding claims,

characterized in that

the further body (5, 25, 40) has regions that are transparent to the electromagnetic radiation (6, 13).

13. Device according to one of the preceding claims,

characterized in that

the measuring device comprises sources (4) of electromagnetic radiation (6, 13).

14. Device according to the two preceding claims,

characterized in that

the sources (4) of electromagnetic radiation are arranged in such a way to the areas (5, 25), which are transparent to the electromagnetic radiation (6, 13), that the areas serve as radiation conductors (5, 25).