EP2574462A2 - Device and method for coating a container and container - Google Patents

Abstract

The apparatus has a coating agent storage unit, and a unit for transmitting the coating material from a coating material supply unit designed for the coating surface transmission arrangement. Water contained in the coating material supply unit is set with a viscosity of less than 100s, in particular to contain paint. A recess is formed at the removal area obtained by removing the coating material from the coated surface of the container. A transfer roller (30) with resilient outer surface is arranged between removal device and applicator device. An independent claim is included for a method for coating a coating surface of cup-shaped container.

Description

The invention relates to a device for coating a coating surface of a preferably cup-shaped container, in particular a food container, with a storage device containing a coating agent and a transfer arrangement designed to transfer the coating agent from the storage device to the coating surface, a coating process that can be carried out with such a device, the use of such Apparatus for coating containers and containers made using such apparatus.

Devices and methods of the type described above are used for example for printing cup-shaped plastic packages for dairy products, such as yogurt. The cup-shaped packs usually have a cylindrical jacket-shaped or frustoconical jacket surface which is to be printed with a desired motif. This is for example from the DE-A-10 2009 043 332 Known methods applied to the motif to be printed on the mug image on a spanned on a rotatably mounted cylinder blanket and transferred from there to the jacket surface to be printed, so the coating surface. This is through Rotation of the cylinder jacket-shaped carrier of the blanket, the previously applied to the blanket motive unrolled on the cup surface. For application of the motif on the blanket usually color is evenly distributed from a storage device in the form of a color box over a plurality of rollers on the lateral surfaces of the rollers and transferred to the plate cylinder. On the plate cylinder a corresponding motif to be printed raised structure is formed so that the color is applied only to the raised lateral surface areas of the plate cylinder and can be transferred from there to the blanket. In this case, a cliché cylinder can be provided for each color of the motif to be printed on which the part to be printed is formed mirror-inverted for the corresponding color. In such devices, the rollers used for removing the ink from the ink fountain and for uniformly distributing the ink together with the plate cylinder and the blanket mounted on the cylinder, ie the blanket cylinder, form a transfer arrangement in the sense of the invention. When using the from the DE-A-10 2009 043 332 known devices for printing on plastic containers, which may be formed for example of PET, polystyrene or the like, it has been found that often only unsatisfactory optical and haptic properties of the printed product can be achieved.

In the EP 1 372 866 B1 For example, a method and apparatus is described for coating PET bottles with a 5% aqueous polyvinyl alcohol-based coating agent by means of a rotary atomizer to improve the barrier properties of the containers. The methods and devices described in the cited document are not suitable for coating cup-shaped containers, because they require a clamping head 37 which can be releasably fixed in a bottle neck and on which the bottles can be suspended.

In view of the problems of the prior art described above, it is an object of the present invention to provide apparatuses and methods for coating preferably cup-shaped containers with which satisfactory optical and haptic properties of the coating surface can be achieved and to provide corresponding containers.

According to a first aspect of the invention, this object is achieved by a development of the known devices, which essentially thereby characterized in that the coating agent contained in the storage device has a viscosity of less than 100 s at 20 ° C in 4 mm DIN cup (DIN 53211), in particular at least partially lacquer, more preferably a UV lacquer contains. In preferred embodiments of the invention, the viscosity of the coating composition is less than 80 s, in particular 60 s or less, but more than 10 s, in particular more than 20 s.

The invention is based on the finding that when using coating compositions with a particularly low viscosity particularly smooth surfaces on the coating surface can be produced, which produce a gloss, which can otherwise be obtained only using shrink films (sleeve) or the like. The device according to the invention and thus carried out coating process therefore allow the production of printed or painted cups with the appearance of slepped cup.

The lacquer is expediently a UV-drying lacquer, preferably a UV-curable polyacrylic lacquer. UV-drying coatings are characterized by very high gloss, high surface smoothness and low odor development during the drying process.

UV-drying lacquers having one or more of the following properties have proven to be particularly suitable: solids content between 95% and 100%, in particular between 98% and 100%, fast-drying, fast-curing, abrasion-resistant, non-scrapable, high-gloss and / or on dried paint applied.

In particular, coatings with a high solids content have proven to be advantageous with regard to the layer thickness which can be achieved thereby and with regard to favorable drying properties.

Conveniently, the coating device according to the invention is set up such that the lacquer layer with a basis weight (wet) of 1.5-6 g / m ² , preferably 2-4 g / m ^{2 is} applied.

The UV-curing lacquer is irradiated with UV light after application and thus cured. The radiated by the UV lamp power can be about 200 watts per cm ² be. An irradiation power to be absorbed by the lacquer layer for hardening at the intended speed is preferably about 165-170 watts per cm ² .

The lacquer layer can be applied to an underlying color layer or alternatively applied directly to the cup-shaped container, which is usually made of plastic.

If desired, the coating surface of a container obtained with a device according to the invention can also be at least partially roughened after completion of the coating in order to obtain desired haptic properties in predetermined lateral surface areas.

For carrying out a contact coating method, the transfer arrangement of a device according to the invention can have a removal device coming into contact with the coating agent contained in the storage device and designed to remove the coating agent from the storage device and an application device designed to apply the removed coating agent to the coating surface. In this case, the removal device similar to that in the DE 10 2009 043 332 A Having described device having a lifting roller with a preferably approximately circular cylindrical jacket and in contact with the in the preferably designed as a colorant box containing coating means removal surface.

In conventional printing units, the color distribution on the squeegee roller is adjusted mechanically by means of screws and slides associated with the ink fountain. In an embodiment which is particularly preferred in the context of the invention, the removal surface of the lifting roller has at least one depression which promotes removal of the coating agent from the storage device. By suitable dimensioning and distribution of the recesses on the removal surface, the desired distribution of the coating composition can be adjusted on the removal surface of the squeegee roller. Furthermore, the provision of the recesses in the removal surface enables removal of a sufficient amount of the coating agent, even if the coating agent has only a low viscosity.

The depressions in the removal surface may be executed dome-shaped or with a surface in the form of spherical shell segments. In this case, the depth and diameter can be selected so that a scoop volume of a total of 9 to 12 cm ³ per square meter of the sampling surface results. The scoop volume is adjusted by appropriate choice of the lift roller depending on the requirements of the case. In a preferred embodiment of the invention, the depressions are introduced by means of a laser engraving. In this case, the depressions can be arranged in a line-shaped circumferential manner, wherein a line density of 100 to 200 lines per centimeter of axial length of the lifting roller can be set. In a preferred embodiment, the line density is 140 to 180 lines per centimeter of axial length, more preferably about 160 lines per centimeter of axial length.

The removal of the coating agent by means of corresponding lifting rollers can be further promoted if the introduced by laser engraving lines do not rotate in radial planes, but in planes that are employed with respect to the radial planes by about 60 °. As a result, the entrainment of the coating agent in the wells is favored. In any case, it has proven to be expedient if a scoop volume of 9 to 12 cm ³ per square meter removal surface is set, wherein even with linear depressions, the scoop volume can be adjusted by selecting appropriate lift rollers. The diameter of the lifting roller is about 40 to 80 mm, preferably 50 to 70 mm, in particular about 61 mm.

Particularly suitable for the removal of the coating agent from the storage device, a rubber roller has been found, wherein the rubber roller is a squeegee roller with a rubber surface such as a solid rubber roller, a rubberized roller, a rubber-coated roller o. The like. The rubber surface coming into contact with the coating agent is preferably rough. Due to the roughness of the rubber surface, the entrainment of the coating agent is promoted by the lifting roller. The surface roughness may be greater than Ra = 0.1 mm and less than Ra = 2.5 mm. Particularly suitable is a surface roughness between Ra = 0.3 mm and Ra = 1.8 mm.

Similar to the ones in the DE 10 2009 043 332 described devices between the removal device and the applicator also at least one transfer roller, Verreiberwalze and / or application roller may be provided, which also has a may have a yielding lateral surface, so as to favor the transfer of the coating agent.

Furthermore, the device according to the invention may have a cliché cylinder arranged between the transfer roller and the applicator with a profiling of the cylinder jacket surface corresponding to a print motif. Thus, due to the profiling, the plate cylinder has a raised structure corresponding to the motif to be printed, so that the ink is applied only to the raised lateral surface areas of the plate cylinder.

The emergence of so-called shadow images on the coated containers can be prevented if the diameter of the plate cylinder corresponds to the diameter of the transfer roller or an integer multiple thereof. In this way, it is ensured that a one-to-one transfer from the transfer roller to the plate cylinder, in which always the same areas of the transfer roller with the same areas of the plate cylinder come into contact, so that no unequal distribution of the coating composition on the raised structure of the Cliched cylinder corresponding surface areas of the transfer roller takes place. Such unequal distribution is observed when a part of the transfer roller surface, which has not been previously contacted with a raised structure of the plate cylinder, comes into contact with a raised structure in a next pass and at the same time a part of the transfer roller comes in contact with the raised structure , which has previously been in contact with the raised structure. This leads to an uneven coating mass transfer from the transfer roller to the plate cylinder. In the dimensioning according to the invention, in which the diameter of the plate cylinder corresponds to the diameter of the transfer roller or an integer multiple thereof, such errors are not observed.

In an alternative, particularly preferred embodiment of the invention, two applicator rollers are arranged between the transfer roller and the plate cylinder, which are provided for transferring the coating agent from the transfer roller to the plate cylinder. Through the interposition of transfer roller and two applicator rollers between the squeegee roller and plate cylinder, the coating agent is particularly evenly transferred to the plate cylinder. The emergence of Shadowing is effectively prevented when the diameter of the plate cylinder is the diameter of the applicator rolls or an integer multiple thereof.

The coating compositions used according to the invention have only a low viscosity. Therefore, under the influence of the centrifugal forces generated by the rotation of the transfer roller and / or the plate cylinder, these coating compositions may jets from the surfaces of the transfer roller and / or the plate cylinder. For this reason, in inventive devices transfer rollers and / or plate cylinders are used with a particularly large diameter of more than 100 mm, preferably more than 120 mm, in particular 150 mm or more, because the centrifugal forces with increasing diameter decrease at the same peripheral speed. However, the diameters of the transfer roller and plate cylinder can not be increased arbitrarily for reasons of space and in view of the desired transfer between the individual elements of the transfer arrangement. Therefore, the diameters of the transfer roller and / or plate cylinder of the devices of the invention are preferably 200 mm or less, more preferably 180 mm or less, more preferably 170 mm or less. To obtain a sufficient coating of the transfer roller by means of the squeegee roller, the ratio of the diameter of the transfer roller to the diameter of the squeegee roller is suitably chosen so that it is greater than 1.5, in particular more than 2, so several revolutions of the squeegee roller for transferring the coating agent to provide on the peripheral surface of the transfer roller. Taking into account the above-mentioned peculiarities of the influence of centrifugal force on liquids of low viscosity, it has proved in the invention, however, to be particularly useful when the ratio of the diameter of the transfer roller to the diameter of the lifting roller is less than 4, in particular less than 3.

As in the device according to DE 10 2009 043 322 For example, the applicator of a device according to the invention can have a blanket cylinder with a resilient outer surface. It is also ensured in the dimensioning of the blanket cylinder that a 1: 1 transmission between the plate cylinder and blanket cylinder takes place. The diameter of the blanket cylinder is therefore an integer multiple of the diameter of the plate cylinder.

The wound on the blanket cylinder cloth can according to the in the DE 10 2009 043 322 be described transfer arrangement and have a forming a transfer surface deformable transfer layer on the side facing away from the transfer surface a greater compliance than the transfer layer having matching layer is arranged. In this case, the transfer layer may have a Shore hardness in the range of 60 to 90 Shore / A, preferably 75 to 80 Shore A and the matching layer a Shore hardness in the range of 15 to 30 Shore A, preferably 22 to 24 Shore A. , With such transmission arrangements and profiled coating surfaces can be coated. This is particularly advantageous in the coating of cups, which have a sealing flange encircling a removal opening, which merges via a stacking edge into a conically downwardly tapering lateral surface area, wherein the stacking edge can be embodied by a convexly curved surface area. The use of the in the DE 10 20 Q9 043 322 described transmission arrangement in devices according to the invention enables the coating of such cups in the region of the stack edge and / or in the region of a bottom region, which can also proceed from the frustoconical jacket surface via a stack edge in the cup bottom.

In the contact printing methods described so far, the coating agent is transferred to the coating surface via a number of contact surfaces, such as the boundary surfaces of the squeegee roller, transfer roller of the plate cylinder, and / or the blanket cylinder. By selecting the surface materials and / or surface structures of the rollers and cylinders as well as by selecting the viscosity of the coating composition, the amount of coating agent to be applied can be set particularly accurately in this printing process. In this way, the gloss, the color, the permeability of the container wall of the container, etc. can be controlled.

Additionally or alternatively, a device according to the invention can also have a contactless transmission arrangement. A contactless transmission arrangement has an atomizing device with which the coating agent received in the storage device is atomized. The container is conveyed for coating by the coating agent mist thus obtained, so that the coating agent droplets can settle on the coating agent surface so as to form the desired coating. In this context, it has proven to be particularly advantageous if the atomizing device for generating an electrically charged paint droplets is designed with a plurality of preferably arranged in a common horizontal plane, in particular lying approximately on a circular line sputtering nozzles and the paint is atomized, in particular with respect to the plate axis approximately radially outward. In other words, the axis of the Tellerzerstäubers is preferably oriented vertically. A Tellerzerstäuber can also be designed as rotatable about a Zerstäuberachse rotary atomizer. Such rotary atomizers are in the EP 1 372 866 B1 described. The disclosure of this document with regard to the structure and function of rotary atomizers is hereby incorporated by explicit reference into this description.

The atomizing device is expediently arranged in a spray chamber which is closed apart from an inlet opening for the containers and an outlet opening for the container. In the course of the coating, the containers are preferably conveyed by means of a conveying device from the inlet opening to the outlet opening along a predetermined path which at least partially, preferably approximately Ω-shaped, circulates the atomizing device. The circulation of the atomizing device results in a particularly effective coating. The conveyor may comprise individual along the predetermined path arranged behind one another carrier elements for cup-shaped container to which the container with downwardly facing container opening are placed such that engaging portions of the support members protrude from below into the container interior. In terms of a uniform coating of the container, it has proven to be expedient if the support elements are designed to rotate the container about an approximately vertical axis of the container.

For painting cups, the present in a horizontal cup bar cups are isolated and placed on the support elements of the conveyor so that the sealing flange of the cup rests on the support element. As carrier elements carrier rings are preferably used with annular bearing surfaces, wherein the usually annular sealing flanges of the cups rest on the annular bearing surfaces. The annular bearing surfaces of the carrier rings can be dimensioned so that cups with different diameters can be placed on the support surfaces. The device according to the invention can then be used to coat cups of different sizes without requiring replacement of the carrier rings of the conveyor.

Preferably, a plurality of identical carrier rings with cups placed thereon are conveyed on an Ω-shaped path around the plate atomizer through the spray chamber, wherein the cups parked on the carrier rings can rotate about their own axis during spraying with the coating agent. Such a coating device works particularly efficiently and coated particularly evenly.

Additionally or alternatively, the conveying device and / or the atomizing device can be assigned a device for generating a relative movement between the atomizing device and the containers placed on the carrier elements in the direction of gravity so as to further promote a uniform coating.

In a preparatory step, the surface of the containers can be polarized. For this purpose, the containers may be subjected to a corona treatment or another surface treatment. A corona treatment polarises a nonpolar plastic surface of the container that is nonpolar in the untreated state and therefore difficult to wet with the coating agent, thereby increasing wettability and chemical affinity of the surface. In this way, a thicker coating agent layer can be applied to the container.

Coating with charged coating droplets may be favored when an outer periphery of the engaging portion of the support members is at least partially electrically conductive and can be adjusted to a predetermined electrostatic potential so as to accelerate the charged particles toward the coating surface.

The engaging portion of the support members may be a vertically movable projection, which is feasible through the central opening of support rings of the support elements. For this purpose, the containers to be coated are placed on the bearing surfaces of the carrier rings and then the projections are retracted through the openings of the carrier rings up into the container interior. The outer boundary surface of the projection is set at least in sections to a predetermined electrical potential. In order for the projection due to its electrical potential on the one hand the coating of predetermined areas of the coating surface and holds the container to another firmly on the support ring, as by the projection slipping of the container from the support ring is prevented. Following the coating process, the projection can be extended downwardly from the container interior and the container is then removed from the carrier ring.

The projection is preferably at least partially cylindrical and / or formed in the form of a metal antenna.

In the alternative embodiment, the projection is immovable and protrudes upward from a central region of the carrier ring. In this case, the containers are placed over the projection prior to coating and placed on the support surface of the carrier ring.

In this connection, it is also contemplated to provide the boundary surface of the engaging portion only partially with a conductive coating so as to achieve a "spot coating" in which a coating limited to the lateral region of the container corresponding to the conductive portion of the engaging portion is applied. The engagement region may also include a pattern of conductive regions which may be separated by insulating regions and separately adjusted to predetermined potentials to create corresponding patterns on the confining surface of the container. Additionally or alternatively, the use of masks or cover coats on the outer periphery of the container is also intended to provide corresponding patterns.

It has surprisingly been found that a coating device according to the invention with annular bearing surfaces for the application of sealing edges cup-shaped container during spraying no bridge of the coating agent between the sealing edges of the container and the bearing surfaces of the carrier rings produced. In other words, during the spraying of the containers parked on the carrier rings, there is no continuous lacquer layer that crosses over the transitions between sealing edges and bearing surfaces. The coated cups can thus be easily removed from the carrier elements after passing through the spray chamber. This effect is due among other things to the low viscosity of the coating composition.

A conveying device of a device according to the invention is preferably associated with a separating device which is used for separating in the form of a stack of cups from cups stacked in cups and designed to pass the singulated cups to the conveyor.

If the coating composition has a UV-curable lacquer which can be cured very quickly under the influence of UV rays, it has proven to be expedient if the conveying device for conveying the lacquered containers is designed by a UV drying chamber, where behind in the conveying direction the UV drying device can also be arranged a stacking device for stacking the painted cups.

As already explained above, the coating surface may have a circular-cylindrical jacket-shaped and / or truncated cone-shaped and / or a convexly curved and / or a concavely curved region, wherein the convex / or. concave areas can form stacking edges, which can also be coated with devices of the invention. An inventive method for coating containers is essentially characterized in that a coating surface of the container is coated with a low viscosity paint of 100 s or less, whereby contact methods and non-contact methods can be used. In both cases, the corresponding coating device has holders for holding the containers to be coated, these containers being expediently cup-shaped with a removal opening and a lateral surface preferably conically tapering from the removal opening in the direction of the bottom and the holding device preferably holds corresponding cups, that the lateral surface is exposed. According to the invention, therefore, an apparatus is used for coating a coating surface of a container with a coating having a viscosity of less than 100 s, or a coating composition having a viscosity of 100 s or less is used to produce a plastic container, preferably polystyrene. PET or the like to coat. A cup according to the invention has a coating which has been produced from a coating composition having a viscosity of less than 100 s, wherein the coating surface of the container can have a circular-cylinder-jacket-shaped, truncated-cone-shaped, convexly curved and / or concavely curved region and is expediently designed as a cup. which has a jacket extending downwardly from an upper opening and preferably tapering towards the container bottom, wherein the upper opening may be circumscribed by a sealing flange which merges via a stacking edge into a frustoconical jacket region.

Figur 1

eine erste Ausführungsform einer erfindungsgemäßen Vorrichtung und

Figur 2

eine Vorrichtung gemäß einer zweiten Ausführungsform der Erfindung,

Figur 3

eine Vorrichtung gemäß einer dritten Ausführungsform der Erfindung,

Figur 4

eine Vorrichtung gemäß einer vierten Ausführungsform der Erfindung in einer schematischen Darstellung, und

Figur 5

eine Schnittansicht einer Trägereinrichtung der vierten Ausführungsform der Erfindung.

In the following, the invention will be explained with reference to the drawing, to which reference is made for all details which are essential to the invention and are not further pointed out in the description. In the drawing shows:

FIG. 1

a first embodiment of a device according to the invention and

FIG. 2

a device according to a second embodiment of the invention,

FIG. 3

a device according to a third embodiment of the invention,

FIG. 4

a device according to a fourth embodiment of the invention in a schematic representation, and

FIG. 5

a sectional view of a support device of the fourth embodiment of the invention.

In the FIG. 1 The apparatus shown comprises a designed as an ink fountain for a coating composition with a low viscosity of 100 s or less, a squeegee roller 20, a transfer roller 30, a plate cylinder 40 and a blanket cylinder 50 and a support for a container or cup to be coated 60th mit the squeegee roller 20, the coating composition is removed from the ink fountain 10 and passed to the transfer roller 30, with which it is transferred to the plate cylinder 40. With the help of the plate cylinder 40, a coloring of the blanket cylinder 50 corresponding to the raised areas 40 of the plate cylinder is effected, the coating material finally being transferred from the blanket cylinder 50 to the container arranged on the carrier 60.

In the FIG. 2 illustrated embodiment of the invention substantially corresponds to the basis of FIG. 1 explained embodiment, wherein in the in FIG. 2 explained embodiment, waiving a blanket cylinder taken from the ink fountain 10 coating composition by means of the lifting roller 20, a first transfer roller 30 and a second transfer roller 40 is transferred to the cup 60. At the in FIG. 1 In the illustrated embodiment of the invention, the diameter of the transfer roller corresponds to the diameter of the plate cylinder, so as to effect a 1: 1 transfer of the coating material from the transfer roller to the plate cylinder. Likewise, the diameter of the first corresponds Transfer roller 30 to the diameter of the second transfer roller 40 in the second embodiment of the invention. The diameters of the plate cylinder and the transfer roller are about 170 mm.

In the FIG. 3 illustrated embodiment of the invention substantially corresponds to the basis of FIG. 1 explained embodiment, wherein in this embodiment, two applicator rollers 35 are arranged between the transfer roller 30 and the plate cylinder. In this way an even more uniform coating result is achieved. On the right in FIG. 3 For example, as in the first embodiment, a blanket cylinder (not shown) may be connected to the plate cylinder 40. The squeegee roller 20 is formed as a rubber roller with a rough surface, which is particularly suitable for removing the paint from the ink fountain 10. The surface roughness of the rubber roller 20 is between Ra = 0.3 and Ra = 1.8 mm, depending on the layer thickness to be applied.

While the FIGS. 1 to 3 Coating apparatuses for a contact printing method, in which the coating agent is transferred to the coating surface via a number of contact surfaces, such as the boundary surfaces of the squeegee roller, the transfer roller, the plate cylinder and / or the blanket cylinder, show the FIGS. 4 and 5 a coating device with a contactless transmission arrangement. Non-contacting transmission arrangements operate independently of geometry, so that containers of any geometry and shape of their lateral surface can be printed with such arrangements, in contrast to contact printing methods.

The coating apparatus 100 of the FIGS. 4 has an atomizing device 79 in the form of a Tellerzerstäubers with perpendicular atomizer axis. Cup-shaped containers are conveyed through the coating agent mist for coating so that the coating agent droplets may settle on the coating surface so as to form the desired coating. The Tellerzerstäuber 79 is designed to produce an electrically charged paint droplets having paint mist.

Stacks 70 of uncoated cups are fed to the coating apparatus 100 via an elevator 71, the cups are singulated and then pass via a conveyor belt 72 to the carrier elements 800, which circulate on a closed path and thereby pass through the spray chamber 810.

The support members 800 have support rings with annular bearing surfaces on which the cups are turned off by means of an erector 73 so that the cup bottom is directed upwards. In other words, the cups bear with their annular sealing edges on the annular bearing surfaces of the carrier rings 800.

The carrier elements are conveyed via positioning screws 74 to a corona treatment station 75 in which the cups are subjected to a surface treatment for polarizing the cup surface.

Via an ionization station 76, the cups resting on the carrier rings 800 pass into the closed spray chamber 810. The inlet opening 77 and the outlet opening 820 of the spray chamber are each covered with air curtains.

In the spray chamber 810, the carrier elements 800 circulate the plate atomizer 79 on an Ω-shaped path. During the spraying, the cups rotate around their own axis. Alternatively or additionally, the cups move during spraying relative to the Tellerzerstäuber in the vertical direction.

Subsequent to the spraying, the cups resting on the carrier elements 800 pass through a drying station 81 in which they are irradiated with UV light and a vacuum receptacle 82. The irradiation with UV light ensures the curing of the UV lacquer used.

The coated cups are then removed from the support members 800, pass through a stack counter 83 and pass onto a packing table 84.

The carrier elements 800, which may be wetted by the coating agent, are cleaned in a cleaning station 85 and then run through the coating cycle again.

Fig. 5 shows a support member 800 of in Fig. 4 shown embodiment of the invention. The carrier element 800 has a carrier ring 900 with an annular bearing surface 910 for placing the cup-shaped container 930. More specifically, the sealing edge 940 of the cup rests on the support surface 910. Through the central opening 920 of the support ring 900 is a projection 78 into the cup inside and out of the Cup inside out in the vertical direction movable. The outer boundary surface of the projection is at least partially electrically conductive and is set to a predetermined electrical potential, so that the charged paint droplets are accelerated in the direction of the projection. In this way it can be controlled, which areas of the lateral surface of the cup are wetted by the paint. Due to its low viscosity, the lacquer does not form a bridge in the transition region between the sealing edge 940 and the support surface 910.

The invention is not limited to the embodiments explained with reference to the drawing. Rather, it is also intended to use contactless coating systems with atomizing devices. Furthermore, three or more transfer rollers can be used. The blanket cylinder may be associated with two, three or more plate cylinder with corresponding two, three or more color boxes.

Claims (28)

Apparatus for coating a coating surface of a preferably cup-shaped container, in particular a food container, with a storage device containing a coating agent and a transfer arrangement designed to transfer the coating agent from the storage device to the coating surface, characterized in that the coating agent contained in the storage device has a viscosity of less than 100 s, in particular contains a lacquer. Device according to Claim 1, characterized in that the transfer arrangement has a removal device which comes into contact with the coating agent contained in the storage device and is designed to remove the coating agent from the storage device, a device designed to apply the removed coating agent to the coating surface and to come into contact with the coating surface Having applicator. Apparatus according to claim 2, characterized in that the removal device has a lifting roller with a preferably approximately circular cylindrical jacket and in contact with the coating means contained in the preferably executed in the form of ink fountain as extraction surface. Apparatus according to claim 3, characterized in that at least one recess which facilitates the removal of the coating agent from the storage device is provided in the removal surface. Apparatus according to claim 4, characterized in that at least one of the recesses is executed dome-shaped or linear, wherein dimensions and density of the recesses are preferably adjusted so that a scoop volume of a total of 9 to 12 cm ³ per square meter results of the sampling area. Device according to one of claims 2 to 5, characterized in that the lifting roller is a rubber roller whose surface roughness is preferably greater than Ra = 0.1 mm and less than Ra = 2.5 mm, in particular greater than Ra = 0.3 mm and smaller than Ra = 1.8 mm. Device according to one of claims 2 to 6, characterized in that between the removal device and the applicator at least one transfer roller with preferably compliant lateral surface and / or at least one applicator roller for applying the coating agent is arranged on a plate cylinder with a printing motif corresponding profiling of the cylinder jacket surface. Apparatus according to claim 7, characterized in that the diameter of the plate cylinder corresponds to the diameter of the transfer roller and / or the diameter of the applicator roll or an integer multiple thereof. Apparatus according to claim 7 or 8, characterized in that the diameter of the transfer roller and / or the plate cylinder is 100 to 200 mm, preferably 120 to 180 mm, in particular 150 to 170 mm. Device according to one of claims 6 to 9, characterized in that the ratio of the diameter of the transfer roller to the diameter of the lifting roller is greater than 1.5, in particular 2 or more and / or less than 4, in particular less than 3. Device according to one of claims 2 to 10, characterized in that the applicator has a blanket cylinder with a resilient outer surface. Device, in particular according to one of the preceding claims, characterized in that the transfer arrangement has a device for atomizing the coating agent. Apparatus according to claim 12, characterized in that the atomizing device is designed to produce a paint mist having electrically charged paint droplets. Apparatus according to claim 13, characterized in that the atomizing device has a Tellerzerstäuber or rotary atomizer with a plurality of preferably arranged in a common horizontal plane, in particular lying approximately on a circular atomizing nozzles, wherein the paint is atomized with respect to the plate axis approximately radially outward. Apparatus according to claim 13 or 14, characterized in that the atomizing device is arranged in a closed spray chamber with an inlet opening for the container and an outlet opening for the container. Apparatus according to claim 15, characterized by a conveyor for conveying the container from the inlet opening to the outlet opening along a sputtering at least partially, preferably approximately Ω-shaped circulating path. Apparatus according to claim 16, characterized in that the conveying device has carrier elements for cup-shaped containers, to which the containers can be placed with the container opening pointing downwards, engagement regions of the carrier elements projecting from below into the container interior. Apparatus according to claim 17, characterized in that the carrier elements have carrier rings with annular bearing surfaces for supporting sealing edges of the cup-shaped containers, wherein the engaging regions are preferably in the vertical direction in the cup interior retractable projections. Apparatus according to claim 17 or 18, characterized in that the carrier elements are designed for rotating the containers about a vertical container axis. Device according to one of claims 15 to 19, characterized by a device for generating a relative movement between the atomizing device and the containers, preferably approximately in the direction of gravity. Device according to one of claims 17 to 20, characterized in that an outer boundary surface of the engagement region is at least partially electrically conductive and is adjustable to a predetermined electrostatic potential. Device according to one of the preceding claims, characterized in that the lacquer is a curable by irradiation with UV radiation lacquer. Apparatus according to claim 22, characterized in that the conveying device for conveying the painted container is designed by a UV drying chamber. Device according to one of the preceding claims, characterized in that the coating surface has a circular cylinder jacket-shaped and / or truncated cone-shaped and / or a convexly curved and / or a concavely curved region. Method for coating containers, in which a coating surface of the containers is coated by means of a device according to one of claims 1 to 24 with a coating composition having a viscosity of less than 100 s, in particular a coating composition containing a lacquer. Use of a device according to Claims 1 to 24 for coating a coating surface of a container with a coating composition having a coating having a viscosity of less than 100 s. Use of a coating composition having a viscosity of less than 100 s for coating cup-shaped containers, in particular food containers. Container produced by a method according to claim 25.

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