Device, use and method for dosing or leveling

Abstract

The invention relates to a device and to a method for metering or leveling a liquid or pasty application medium onto a running surface, comprising a metering element for contacting the application medium in a contact region, and a pressing unit for pressing the metering element against the running surface, the metering element is made entirely or partially of a magnetic or ferromagnetic material, and the device further comprises at least one magnet element which is arranged such that a magnetic force acts on the metering element between the pressing unit and the contact region, in particular in the region of the contact region.

Description

Technical Field

[0001] The invention relates to a device for metering or leveling a liquid or pasty coating medium onto a moving surface according to the preamble of claim 1, as well as to an associated method and use. Background Art

[0002] When finishing fiber webs, for example when coating or sizing paper, cardboard and packaging webs, liquid or pasty coating agents are usually applied to the fiber web or to a transfer surface as a thin liquid film. Typically, these films have a thickness in the range of 1 µm to 100 µm. For metering the coating agent, both volumetric and hydrodynamic metering principles can be used.

[0003] For example, the dosing devices known from EP 1761341 B1 and WO 02 / 27097 can be used for dosing. Here, a grooved scraper bar is used for volumetric dosing, while a smooth scraper bar is used for hydrodynamic dosing. As shown in WO 02 / 27097, a scraper blade can also be used for dosing. In the case of volumetric dosing, the scraper bar contacts the coating surface, while in the case of hydrodynamic dosing, the scraper bar or scraper blade floats and does not contact the coating surface (hydroplaning effect). However, these two dosing principles can also be implemented in other ways. Therefore, a blade can also be used as a dosing element for hydrodynamic dosing.

[0004] All hydraulic metering elements have in common that they do not come into direct contact with the substrate, since they float on a liquid film (as in the case of water skiing) without contacting the surface of the application roller or of the substrate.

[0005] Volumetric metering is mainly used when the coating liquid has a very low "low shear viscosity" (e.g. Brookfield viscosity < 200 mPas at 100 rpm) or when the machine speed is so low (< 1000 m / min) that the available hydraulic metering elements cannot generate sufficient hydraulic forces to form the film. Volumetric metering is also used if greater film thicknesses (> 25 µm) need to be applied directly or indirectly to the fiber web.

[0006] Hydrodynamic metering is only used or can only be used if the "low shear viscosity" of the coating medium is high (e.g. Brookfield viscosity > 800 mPas) or if the "high shear viscosity" of the coating medium is high (e.g. > 80 mPas, measured with a capillary viscometer at high shear rates > 1.E-05). In order to be able to use hydrodynamic metering, the geometry of the metering element must be designed in such a way that it generates sufficient hydrodynamic pressure below the metering element so that a liquid film with the desired film thickness can be formed. The longer the contact length between the liquid and the metering element, the greater the hydrodynamic force generated below the metering element. The faster the machine speed or the higher the viscosity, the greater the hydrodynamic force generated, so that a wide working window can be achieved for adjusting and controlling the wet film thickness.

[0007] The starch coating (sizing) by means of a film laminator is a common and increasingly economical application for film coating. In this case, a starch film is metered onto the surface of a transfer roll and then transferred to the fibrous web in a transfer nip. In particular, when sizing packaging paper, there is a tendency to use transfer rolls with harder surfaces. Such a film laminator is described, for example, in DE 102018100924 A1.

[0008] In such applications, it is often the case that at low production speeds and / or when a low viscosity of the starch solution is technically required, the desired wet film thickness cannot be generated using a hydraulic dosing element. These required film thicknesses can only be produced by a volumetric dosing element.

[0009] However, the volumetric dosing element must be in direct contact with the coating surface, in this case with the transfer roller. As a result, the dosing element or the transfer roller wears very quickly. This can also cause negative marks in the coating pattern on the substrate. Summary of the invention

[0010] The object of the present invention is to overcome the limitations of hydraulic metering elements.

[0011] In particular, the object of the present invention is to provide a hydraulic metering element which has a significantly increased range of applications compared to the prior art.

[0012] Furthermore, the object of the invention is to expand the range of use of the laminator, in particular in the area of ​​hard nip sizing.

[0013] Unless expressly stated otherwise, within the scope of this application, the viscosity of the coating medium is always referred to as the “high shear viscosity”, ie the viscosity measured with a capillary viscometer at a high shear rate > 1.E-05.

[0014] This object is achieved according to the invention by a device according to independent claim 1 and a method according to claim 14. Further advantageous embodiments of the invention are found in the dependent claims.

[0015] With regard to the device, the invention is solved by a device for metering or leveling a liquid or pasty coating medium onto a running surface. The device comprises a metering element for contacting the coating medium in a contact zone and a pressing unit for pressing the metering element onto the running surface. According to the invention, it is provided that the metering element consists entirely or partially of a magnetic material, in particular a ferromagnetic material, and that the device further comprises at least one magnetic element which acts repulsively or attractively on the metering element.

[0016] In one embodiment, it can be provided that the magnetic element is arranged in such a way that a magnetic force acts on the metering element between the pressing unit and the contact area, in particular in the region of the contact area. In this embodiment, it is advantageous if at least one magnetic element is designed in such a way that the magnetic force reacts to the pressing force of the pressing unit and acts on the metering element in an especially attractive manner. The magnetic force acts as a restoring force on the metering element.

[0017] In other embodiments, it can be provided that the magnetic force acts on the metering element in a repulsive manner and assumes the function of the extrusion unit in whole or in part. In this embodiment, it is advantageous to provide the metering element with a restoring force, which acts against the repulsive magnetic force. This can be achieved via a restoring mechanism, for example via a preloaded or bent elastically resilient blade, via a preloaded, elastically resilient holder of a scraper rod or via a similar mechanism.

[0018] In the embodiment with the repulsive magnetic element, magnetic force is of vital importance for the work of the dosing device. The repulsive magnet assumes the function of the extrusion unit here. The extrusion force of the dosing element can be adjusted by changing the magnetic force. For example, the restoring force realized by the preloaded or bent blade with elastic resilience or the preloaded retaining portion with elastic resilience of the scraper rod can be affected and sensitively adjusted by changing the repulsive magnetic force. In this respect, this embodiment is very advantageous, because the dosing device only needs very few mechanical parts, and is therefore simple to manufacture and low in cost.

[0019] Here, elements known from the prior art, such as metering blades or metering elements with scraper bars, can be used as metering elements. It is advantageous to use smooth, groove-free scraper bars. The scraper bar can be a hard or soft scraper bar, and its surface can be made of rubber, polyurethane or metal, for example.

[0020] It is advantageous that metering blades are applied in the equipment according to aspect of the present invention, because these metering blades are usually made of magnetic or ferromagnetic material. Yet this magnetic or ferromagnetic element can also be placed on the metering device with scraper bar very easily.

[0021] As with the metering devices known from the prior art, within the scope of the invention, the pressing force with which the metering element is pressed against the moving surface can also be adjusted via a pressing unit. Typically, these pressing units are mechanical pressing units, wherein the pressing force can be generated, for example, by means of an adjustment screw, by means of a pressing hose or by means of a deflection.

[0022] In particular when using a metering blade as the metering element, the blade geometry, such as the blade deflection and the position of the contact zone, can also be adjusted by means of the pressing unit.

[0023] The contact zone is the region in which the metering element is in contact with the coating medium or the region in which hydrodynamic forces act on the metering element.

[0024] The inventors have recognized that by adding a magnetic field, in particular in the region of this contact zone (for example in the form of one or more magnetic elements), the pressing force can be influenced very precisely and specifically, in particular can be reduced.

[0025] This allows a significantly increased range of applications, especially in the case of hydrodynamic dosing elements. In order for the so-called "hydroplaning effect" to occur, the force generated by the hydrodynamic force must be sufficiently large to compensate for the extrusion force of the dosing element. This is not possible in many relevant applications due to the low speed of the coating medium or due to its low viscosity.

[0026] However, when the pressing force is reduced, the blade geometry may be changed, which is usually undesirable. In addition, the known pressing devices only allow a rough and relatively imprecise adjustment of the pressing force.

[0027] Now, with the proposed magnetic element, the extrusion force can be influenced very specifically and also very sensitively. The magnetic element acts on the metering element, which for this purpose must be made of a magnetic or ferromagnetic material or must include at least one element consisting of a magnetic or ferromagnetic material. In principle, this action can be repulsive or attractive. However, in order to be able to realize or support hydrodynamic metering, it is advantageous here if at least one magnetic element is designed so that the magnetic force reacts to the extrusion force of the extrusion unit. In this case, the magnetic element reduces the extrusion force exerted by the metering element on the surface in motion without causing significant geometric changes in the positioning and deflection of the metering element.

[0028] A further advantage of the device is that by providing the magnetic element it is possible to influence the pressing force without the geometry of the metering element (such as blade deflection or contact area) changing noticeably. In the case of metering blades, a magnetic field often changes the rigidity of the blade, but the blade hardly deforms.

[0029] For an external observer, the effect of the magnetic element is similar to that in the case of hydrodynamic metering of a liquid or pasty film, such as a (virtual) increase in the viscosity of the coating medium.

[0030] The proposed solution is also advantageous because it can also be retrofitted very easily into existing systems. In this case, it is only necessary to add the magnetic element to the holding device of the dosing element. The magnetic element can also be sensitively guided without great difficulty using an accurate positioning device. This allows the user to greatly expand the variety of applications of his coating device with little effort. Since the restoration by disassembling the magnetic element is also very convenient and quick, the user also does not have any risks when retrofitting, which further increases the acceptance of the new device.

[0031] The magnetic element can be embodied as an electromagnet or as a permanent magnet.

[0032] It can be provided that the distance between the magnet element and the metering element is less than 20 mm, in particular less than 10 mm, in particular less than 5 mm. A distance of 1 mm or less is also possible.

[0033] In an advantageous embodiment, it can be provided that the magnetic force acting on the metering element is controllable. In particular, it can also be provided that the effect of the magnet on the metering element is completely or largely turned off.

[0034] When using a suitable electromagnet, this control can be achieved very easily via the control of the current intensity. However, when using a permanent magnet, the magnetic force can also be controlled. Thus, it can be provided, for example, that the distance between the magnet element and the dosing element is adjustable.

[0035] In principle, a manually operable adjustment device is conceivable for such an adjustment, but for such a distance adjustment it is advantageous if at least one servomotor is provided in order to adjust the distance between the magnet element and the metering element. Using such a servomotor, in particular a linear servomotor, a very precise and sensitive adjustment of the distance can be achieved. In this case, a movement of the magnet relative to the magnetic or ferromagnetic part of the metering element in the μm range or in the range of 1 / 10 mm can be achieved, whereby the magnetic force acting on the metering element can be reduced or increased in very small steps. Thus, a relief of the metering element by the magnetic force can be achieved in very small steps.

[0036] This very sensitive variation of the pressing force achieved by the pressing element is not possible with the pressing elements customary today.

[0037] In modern installations such as paper machines, the metering element may extend for 10 m or more. In order to be able to achieve a uniform control of the forces acting on the metering element, it is advantageous if the magnet element extends (in the cross-machine direction) over the entire length of the metering element.

[0038] Such a long magnetic element can be realized in many ways. Therefore, the magnetic element can be implemented as a continuous magnetic strip, for example. Alternatively, the magnetic element can be constructed by a plurality of individual magnets arranged side by side. The spacing of these individual magnets can be matched according to the type of the dosing element and the material used. The spacing between two adjacent magnets is usually 10 mm or larger, especially 20 mm or larger. When using a magnetic dosing strip (which is composed of a plurality of magnet segments arranged in a row), the pitch (and thus the spacing between adjacent magnet segments) can be in the range of 50 mm to 100 mm, or higher than 100 mm in individual cases.

[0039] It is particularly advantageous if a mechanism is provided for shaping the magnetic force over the length of the dosing element and thus in the machine transverse direction in the case of an installed device. This allows the effective extrusion force acting on the surface in motion to be shaped very accurately. This mechanism is implemented, for example, by providing a servomotor for a plurality of these magnets, in particular all of them, in the case of a plurality of individual magnets, in order to adjust the spacing between the magnets and the dosing element. Alternatively, a plurality of electromagnets can also be used, the magnetic forces of which can be varied independently of one another, for example by varying the current intensity. Alternatively, manual adjustment via a spindle with a fine spindle thread is also feasible.

[0040] In a preferred embodiment, it can be provided that the magnetic force per centimeter is between 0.01 g / cm and 10 kg / cm, preferably between 0.1 g / cm and 10 kg / cm, in particular between 0.05 g / cm and 5 kg / cm, particularly preferably between 0.5 g / cm and 3 kg / cm. It is particularly advantageous if the magnetic force acting on the metering element can be varied within a given range, for example by changing the distance between the magnetic element and the metering element.

[0041] In order to achieve stable operation of the device, it is advantageous that the magnetic or ferromagnetic material used does not lose its (ferro)magnetic properties even when the temperature at the place of use increases (for example due to operating errors or special production conditions). Therefore, in a preferred embodiment, it is provided that the Curie temperature (T C) is at least 80°C, in particular at least 100°C. This is particularly advantageous when a starch solution is used as the coating medium. This starch solution must be heated before coating. Depending on the starch used (wheat starch / potato starch / corn starch / barley starch), different temperatures are required for gelatinization, so that the degree to which the metering element is heated by contact with the starch will necessarily also vary. However, in the case of a Curie temperature of over 80°C, in particular over 100°C, the metering element can be used for all common starch types without the risk of magnetic or ferromagnetic materials losing their magnetism and thus impairing the function of the metering device.

[0042] In addition to iron (T C = 759°C) and nickel (T C = 353℃), CrO2 (T C = 116°C) have also been shown to have a corresponding Curie temperature. Neodymium magnets can be adjusted to a Curie temperature of over 100°C. These materials are therefore particularly suitable for use as magnetic or ferromagnetic materials for metering elements.

[0043] Neodymium magnets are particularly suitable since they can provide a high magnetic force with a small material volume, which enables a compact design of the coating device.

[0044] With regard to the method, the object is achieved by a method for metering or leveling a liquid or pasty coating medium onto a moving surface, wherein the coating medium is first applied to the moving surface and then metered or leveled with the aid of a device, wherein the device is implemented according to aspects of the invention.

[0045] The running surface can be either a material web to be coated, such as a paper web, packaging web or cardboard web ("direct coating"). Alternatively, the running surface can also be the surface of a transfer element, in particular a transfer roller, from which the coating medium is then transferred to the material web.

[0046] In an advantageous embodiment of the method, it can be provided that the coating medium has a “high shear viscosity” of less than 80 mPas and / or a film thickness of between 5 μm and 100 μm, in particular between 5 μm and 50 μm.

[0047] The use of starch solutions as coating medium is a particularly preferred embodiment.

[0048] Alternatively, low-viscosity coating liquids for producing barrier layers (water vapor barriers, grease barriers, oxygen barriers, bacteria barriers, light barriers, etc.) can also be used as coating medium.

[0049] The advantages of the device according to aspects of the invention are particularly evident when such a device is used for metering or leveling a liquid or pasty coating medium onto a running surface, wherein the running surface is the surface of a roller and wherein the surface has a hardness between 60 Shore D and 100 Shore D, preferably between 80 Shore D and 95 Shore D. Such rollers are increasingly being used in the field of starch coating. In the case of so-called hard nip sizing, in a laminator, a starch solution is metered onto two hard rollers, and the two hard rollers then transfer the starch from the transfer gap formed by the two rollers to the fiber web.

[0050] In the case of such hard surfaces, the use of contact metering systems is undesirable due to the high degree of wear. Therefore, non-contact hydraulic metering systems have particularly great advantages here. Compared with previous hydraulic metering, the device proposed here allows a significantly larger range of applications. The range of applications of the laminator in the field of hard nip sizing is also significantly expanded as a result.

[0051] When metering the surfaces of rotating rollers, in particular hard rollers with a surface hardness between 60 Shore D and 100 Shore D, it is particularly advantageous if the concentricity deviation is very small, in particular in the range of ≤ 40 µm. This is particularly advantageous for stable hydrodynamic metering with uniform film thickness.

[0052] When metering the rotating roll, the coating medium can be transferred from the roll surface to the fibrous web, such as a paper, cardboard or packaging web, by means of a transfer nip. In this case, it is referred to as indirect coating.

[0053] Alternatively, the coating medium can be metered directly onto the fiber web as a running surface. In the case of direct coating of the surface of the fiber web, the fiber web can be guided on a roller, in particular in the area where the coating takes place.

[0054] In the case of direct as well as indirect coating, the fiber web can have a g / m 2 With 400 g / m 2 between, preferably between 40 g / m 2 ~120 g / m 2 The weight per unit area is between .

[0055] The running surface may have a speed of more than 1000 m / min, in particular more than 1500 m / min, preferably 1800 m / min or more. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The present invention is explained below in conjunction with the accompanying drawings. The present invention is not limited to these embodiments. In detail:

[0057] Figure 1 An apparatus for dosing and leveling according to aspects of the invention is shown;

[0058] Figure 2 An apparatus for dosing and leveling according to a further aspect of the invention is shown;

[0059] Figure 3a and Figure 3b Aspects of the mode of action in a variant according to the invention are schematically shown;

[0060] Figure 4a and Figure 4b An apparatus for dosing and leveling according to a further aspect of the invention is shown;

[0061] Figure 5 Aspects of the mode of action in another variant of the invention are schematically shown. DETAILED DESCRIPTION

[0062] Figure 1 The device according to aspects of the present invention is shown. Here, in this embodiment, a metering blade 1 is used as a metering element 1. The metering blade 1 is pressed against a moving surface 5 by means of a pressing unit 2. The pressing unit 2 is implemented as a mechanical pressing unit 2, wherein the pressing is controlled by means of an adjustment screw. A plurality of such adjustment screws are arranged on the length of the metering element 1 in order to be able to achieve shaping of the pressing force. However, alternatively, other implementations of the pressing unit 2 are also feasible and applied.

[0063] The coating medium 4 is applied to the running surface 5 by means of a coating device (not explicitly shown). The coating blade 1 is in contact with the coating medium 4 in a contact area 6. If the coating medium 4 is applied in excess, the excess coating medium 4 can be removed by the metering blade 1, so that only the desired amount remains on the running surface 5. Alternatively or additionally, the coating medium 4 can also be leveled by the blade 1 over the length of the metering element 1.

[0064] In addition, a magnetic element 3 is also provided in the device. The magnetic element 3 is arranged so that the magnetic force is exerted between the pressing unit 2 and the contact area 6 (such as Figure 1 directly in the region of the contact zone 6) acts on the metering element 1. Figure 1 In the embodiment shown, the entire metering element 1 is made in the form of a metering blade 1 made of a magnetic or ferromagnetic material. Alternatively or additionally, it can also be provided that an element made of a magnetic or ferromagnetic material is arranged on the metering element 1 in the region of the contact area 6.

[0065] The magnetic element 3 can be realized via an electromagnet or a permanent magnet. A plurality of such magnets can be arranged side by side over the length of the metering element 1 in order to enable shaping. Alternatively, the magnetic element 3 can also be implemented as a continuous magnetic strip 3.

[0066] Neodymium magnets are particularly suitable since they provide a high magnetic force with a small material volume, which enables a compact design of the coating device.

[0067] Advantageously, the magnetic force acting on the metering element 1 can be controlled. Figure 1 In the embodiment of , this is achieved by making the distance between the magnet element 3 and the metering element 1 adjustable. For example, this can be achieved by a suitable servomotor, such as a linear servomotor.

[0068] Figure 2 An alternative implementation of a device according to aspects of the invention is shown. Figure 1 The difference is that here, the metering element 1 is not a metering blade 1. Instead, metering is performed by means of a scraper rod 8 rotatably supported on a holder. Figure 2 The implementation of a hydrodynamic dosing is also shown. The scraper 8 is preferably designed as a smooth scraper 8 for this purpose. The scraper contacts the coating medium 4 in the contact zone 6, but does not directly contact the running surface 5 in the case of hydrodynamic dosing. The holder for the scraper 8 is usually made of a non-magnetic plastic material. However, in order to still enable the magnetic force of the magnetic element 3 to act on the dosing element 1, an additional element 7 made of a magnetic or ferromagnetic material is provided here by way of example, which is arranged on the dosing element 1, especially in the area of ​​the contact zone.

[0069] The design of the extrusion unit 2 and the magnetic element 3 is Figure 1 The corresponding elements in are the same.

[0070] Figure 3a and 3b An aspect of the mode of operation of an embodiment of the present invention shall once again be shown by way of example. Figure 3aHere the force situation in the contact zone 6 is shown. Here the pressing force F-klinge of the metering blade 1 acts in the direction of the running surface 5, while the hydrodynamic force F-hydrodyne of the coating medium acts in the opposite direction. In this case, for example, very low film thicknesses are usually obtained in the case of a low "high shear viscosity" of the coating medium 4, because due to the additional low speed of the running surface 5, the resultant force ΔF in the direction of the blade force F-klinge exceeds the hydrodynamic force. Therefore, this resultant force ΔF will be directed in the direction of the running surface 5 and reduce the film thickness until equilibrium is reached. As a result, the desired floating ("hydroplaning") of the metering element does not occur and the metering element 1 may even touch the running surface 5, because no "lubricating film" is formed.

[0071] like Figure 3b As shown, in the device according to aspects of the present invention, a magnetic force F-magnet is now also added as an additional force component. This magnetic force acts in the same direction as the hydrodynamic force F-hydrodyn. The magnetic force F-magnet can now advantageously be adjusted in such a way that the resultant force ΔF no longer points in the direction of the blade force F-Klinge, but in the direction of the hydrodynamic force F-hydrodyn. Here, in an embodiment according to aspects of the invention, the resultant force ΔF can be adjusted very precisely via the adjustment of the magnetic force F-magnet, so that, for example, the desired film thickness is achieved despite a low viscosity of the coating medium 4 or a low speed of the moving surface 5.

[0072] Figure 4a and Figure 4b A possible implementation of a device according to aspects of the invention is shown. Figure 4a The equipment here is Figure 2 The device in FIG. 1 corresponds largely to that in FIG. 2 , except that the element 7 made of magnetic or ferromagnetic material is replaced by a further magnetic element 3 a. The two magnetic elements 3 , 3 a are arranged relative to each other in such a way that they attract each other. This embodiment thus functions in a similar manner to Figure 2 The embodiment in is basically similar, however, the effective magnetic force is increased by the additional magnetic element 3a compared to the element 7 made of magnetic or ferromagnetic material.

[0073] Figure 4b The device in the embodiment also replaces the element 7 made of magnetic or ferromagnetic material with another magnetic element 3a. Figure 4a compared to, Figure 4b The magnetic elements 3, 3a in are arranged relative to each other in such a way that they repel each other!

[0074] In accordance with Figure 4a In the embodiments of the invention, the metering element 1 is pressed by the pressing unit 2 in the direction of the running surface 5. The attraction of the magnetic elements 3, 3a counteracts the blade force and relieves the metering element. In these embodiments, the magnetic force thus acts in the direction of the hydrodynamic force, while the blade force counteracts the hydrodynamic force.

[0075] In such Figure 4b In the embodiment shown in , the magnetic force counteracts the hydrodynamic force. For this purpose, the metering unit 1 is designed so that the blade force acts in the direction of the hydrodynamic force. The metering device 1 has a blade part or a spring part, which should push the metering device 1 away from the running surface 5. The function of the pressing unit 2 is assumed by the repelling magnetic elements 3, 3a.

[0076] Figure 5 Schematically shows Figure 4b Here, too, the magnetic force F-magnet acts on the blade force F-klinge. Here, too, the magnetic force F-magnet can be adjusted very sensitively so that the force ΔF resulting from the magnetic force F-magnet acting on one side and the F-klinge and the hydrodynamic force F-hydrodyne acting on the other side has the desired value.

[0077] In accordance with Figure 1 , Figure 2 or Figure 4a In the embodiment of the invention, the attractive magnetic force F-magnet is only used to adjust the resultant force ΔF. In the embodiment with repulsive magnetic elements 3, 3a, the magnetic force F-magnet is essential for the operation of the metering device. The repulsive magnets 3, 3a assume the function of the squeezing unit 2. The squeezing force of the metering element 1 can be adjusted by changing the position of the magnet 3 relative to the position of the repulsive magnet 3a. By changing the repulsive magnetic force F-magnet, the pre-tightened retaining portion with elastic rebound energy of the pre-tightened or bent blade or scraper rod with elastic rebound ability can be influenced and sensitively adjusted. In this respect, this embodiment is very advantageous because the metering device requires fewer mechanical parts and is therefore simpler and more cost-effective to manufacture.

[0078] In the embodiment with an attractive magnet or with an attractive magnet and a ferromagnetic scraper element, it is possible in principle that the magnet element 3 and the scraper element 7 attract each other too strongly, so that the ferromagnetic scraper element suddenly jumps up and adheres to the magnet. This state is undesirable.

[0079] This occurs if the distance between the magnet element 3 and the ferromagnetic or magnetic scraper element 7 is below a certain minimum. This behavior does not occur in embodiments with repelling magnets, because the repelling force increases when the distance between the magnets 3, 3a decreases.

[0080] Reference numerals list

[0081] 1 metering element

[0082] 2 Extrusion units

[0083] 3 Magnetic elements

[0084] 3a Magnetic element

[0085] 4 Coating medium

[0086] 5 Moving Surfaces

[0087] 6 Contact Area

[0088] 7. Components made of magnetic or ferromagnetic materials

[0089] 8 Scraping rod

Claims

1. A device for metering or leveling a liquid or pasty coating medium (4) onto a running surface (5), the device comprising a metering element (1) for contacting the coating medium (4) in a contact zone (6) and a pressing unit (2) for pressing the metering element (1) against the running surface (5), characterized in that: The dosing element (1) is made entirely or partially of a magnetic or ferromagnetic material, and the device further comprises at least one magnetic element (3) which acts repulsively or attractively on the dosing element (1).

2. The device according to claim 1, characterized in that The magnetic element (3) is arranged so that a magnetic force acts on the metering element (1) between the pressing unit (2) and the contact area (6), in particular in the area of ​​the contact area (6), wherein the at least one magnetic element (3) is implemented so that the magnetic force counteracts the pressing force of the pressing unit (2), and the magnetic force acts on the metering element (1) in an attractive manner.

3. The device according to claim 1, characterized in that The magnetic force acts on the metering element (1) in a repulsive manner and fully or partially assumes the function of the pressing unit (2).

4. The device according to claim 3, characterized in that The metering element has a restoring mechanism which counteracts the repelling magnetic force.

5. The device according to any one of the preceding claims, characterized in that The metering element (1) comprises a metering blade (1) or a scraper rod (8).

6. The device according to any one of the preceding claims, characterized in that The magnetic force acting on the metering element (1) can be controlled.

7. The device according to claim 6, characterized in that The distance between the magnetic element (3) and the metering element (1) is adjustable.

8. The device according to claim 7, characterized in that At least one servomotor, in particular a linear servomotor, is provided in order to adjust the distance between the magnet element (1) and the metering element (1).

9. The device according to any one of the preceding claims, characterized in that The distance between the magnetic element (3) and the metering element (1) is less than 20 mm, in particular less than 5 mm, preferably 1 mm or less.

10. The device according to any one of the preceding claims, characterized in that The magnetic element (3) extends in the cross-machine direction over the entire length of the metering element (1).

11. The device according to any one of the preceding claims, characterized in that Means are provided for shaping the magnetic force over the length of the metering element (1).

12. The device according to any one of the preceding claims, characterized in that The magnetic force per centimeter is between 0.01 g / cm and 10 kg / cm, in particular between 0.05 g / cm and 5 kg / cm, particularly preferably between 0.5 g / cm and 3 kg / cm.

13. The device according to any one of the preceding claims, characterized in that The magnetic or ferromagnetic material has a Curie temperature of at least 80° C., in particular at least 100° C.

14. A method for metering or leveling a liquid or pasty coating medium (4) onto a moving surface (5), wherein: The coating medium (4) is first applied to the running surface (5) and then metered or leveled by means of a device, characterized in that the device is embodied in accordance with one of the preceding claims.

15. The method according to claim 14, characterized in that The coating medium (4) has a "high shear viscosity" of less than 80 mPas and / or is metered to a film thickness of between 5 µm and 100 µm, in particular between 5 µm and 50 µm.

16. Use of the device according to any one of claims 1 to 13 for metering or leveling a liquid or pasty coating medium (4) onto a moving surface (5), wherein: The running surface (5) is the surface (5) of a roller, and wherein the surface (5) has a hardness between 60 Shore D hardness and 100 Shore D hardness, preferably between 80 Shore D hardness and 95 Shore D hardness.

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