EP3112176B1 - Coating device and associated coating method - Google Patents

Description

The invention relates to a coating device for coating, in particular painting, motor vehicle body components with a paint. The invention also relates to a corresponding coating method.

Figure 1 shows a cross-sectional view through a conventional painting installation for painting motor vehicle body components. Here, the motor vehicle body components to be painted are transported on a conveyor 1 at right angles to the plane of the drawing through a painting booth 2 in which the motor vehicle body components are then painted in a conventional manner by painting robots 3, 4. The painting robots 3, 4 have several pivotable robot arms and each guide an application device, such as a rotary atomizer, an air atomizer or a so-called airless device, via a multi-axis robot hand axis.

The disadvantage of these known application devices, however, is the sub-optimal application efficiency, so that part of the sprayed paint called overspray does not land on the motor vehicle body component to be painted and has to be removed from the paint booth 2 with the booth air. A so-called plenum 5 is therefore located above the paint booth 2, from which air is introduced into the paint booth 2 through a ceiling 6 of the paint booth 2 downwards in the direction of the arrow. The cabin air then comes with the overspray contained therein down from the painting booth 2 into a washout 7 located below the painting booth 2, in which the overspray is again removed from the booth air and bound to water.

This wastewater with the overspray contained in it then has to be treated again in a complex process, whereby the paint sludge that arises is hazardous waste and has to be disposed of in a correspondingly complex manner.

In addition, the air speed in the painting booth 2 must be at least in the range of approx. 0.3-0.5 m / s in order to quickly remove the overspray produced during painting from the painting booth 2.

Furthermore, the overspray produced during painting can temporarily and locally create an explosive atmosphere, so that the relevant statutory ATEX product guidelines (ATEX: Atmosphere explosible) must be observed.
On the one hand, because of their unsatisfactory application efficiency and the resulting overspray, the known application devices cause high investment costs for the required washing out and the necessary explosion protection.
On the other hand, due to the overspray produced during operation, the known application devices are also associated with high operating costs due to paint losses and the disposal costs for disposing of the overspray.
The invention is therefore based on the object of creating a corresponding improvement. See also document EP2208541 .

DE 10 2004 044 655 A1 discloses a coating device for painting a curved surface, in particular an aircraft or an automobile, with a nozzle print head of the inkjet type, which is moved by a multi-axis robot along a predeterminable path over the surface to be painted. To maintain a certain distance between the print head and the surface to be painted, a laser measurement system is provided that measures a relative position of the print head with respect to the surface and transmits the measured relative position to a control unit of the robot for corresponding readjustment of the distance.

The above-mentioned object is achieved by a coating device according to the invention and a corresponding coating method according to the independent claims.

The invention encompasses the general technical teaching of using an application device with such a high application efficiency that it is possible to dispense with washing out, in which the overspray is conventionally washed out of the cabin air. In the preferred exemplary embodiment, one advantage of the coating device according to the invention is that a separate washout can be dispensed with. However, the invention is not limited to painting systems that have no washout at all. Rather, through the use of application devices with a higher transfer efficiency, there is the possibility of a smaller dimensioning of the washout, if it is not possible to do without it completely.

The application device is preferably a print head of the type used in a similar form, for example, in inkjet printers. For example, it can be a bubble jet print head or a piezo print head act. However, with regard to the technical principle of the print head used, the invention is not limited to bubble jet print heads and piezo print heads, but can in principle also be implemented with other ejection mechanisms.

Furthermore, within the scope of the invention there is the possibility that the print head ejects the coating agent pneumatically. For example, the individual droplets of coating agent can be ejected by short air pulses, which the drops of coating agent in the direction of the to be coated Accelerate component, whereby the painting distance can be increased.

It should also be mentioned that the print head can either eject the coating agent in individual coating agent droplets or continuously. In addition, within the scope of the invention there is the possibility that some of the coating agent nozzles of the print head continuously eject the coating agent, whereas another part of the coating agent nozzles of the print head ejects the coating agent in individual coating agent droplets.

In the preferred embodiment of the invention, the print head is positioned by a multi-axis robot, the robot preferably having a plurality of pivotable robot arms and a multi-axis robot hand axis on which the print head is mounted.

Alternatively, there is also the possibility that the print head is attached to a machine which positions the print head so as to be movable relative to the component to be coated. For example, such a machine can be a conventional roof machine or a side machine, which are known per se from the prior art and therefore do not need to be described in more detail.

In contrast to the conventional print heads, which are used, for example, in inkjet printers, the print head in the coating device according to the invention preferably has a significantly greater surface coating performance, which is preferably greater than ¹ m ² / min., 2 m ² / min., 3 m ² per minute or 4m ² / min. is.

In contrast to conventional inkjet printers, the print head in the coating device according to the invention must also be able to apply liquid lacquers that contain solid lacquer components, such as pigments and so-called metallic flakes (Mika's). The individual coating agent nozzles of the print head are therefore preferably adapted in terms of their size to the solid paint components, so that the print head can also apply paints with the solid paint components.

In the case of the coating device according to the invention, too, the application device is preferably arranged in a painting booth in which the components are coated with the coating agent. Painting booths of this type are known from the prior art and therefore need not be described in more detail.

However, it has already been mentioned above that the pressure heads used as application devices within the scope of the invention have a significantly greater application efficiency than conventional application devices, such as rotary atomizers. The washout located below the painting booth can therefore be dimensioned much smaller than in conventional painting systems with rotary atomizers as application devices. In one embodiment of the invention, the high transfer efficiency of the print heads used as application devices even enables a complete waiver of washing out or other costly filter measures, such as dry separation or the like below the paint booth. In In this case, simple filters that are replaced or cleaned cyclically (e.g. weekly, monthly, half-yearly or yearly).

Furthermore, the high transfer efficiency of the print heads used as application devices in the context of the invention makes it possible to dispense with explosion protection measures in accordance with the relevant statutory ATEX guidelines, since less overspray is generated and therefore no explosive atmosphere is created during operation. In one embodiment of the invention, therefore, no explosion protection is provided in the painting booth.

However, in the coating device according to the invention, too, an air suction device is preferably provided which sucks the booth air out of the painting booth, the suction preferably taking place downwards. The booth air is preferably sucked off through an air filter that filters the overspray from the booth air, whereby the air filter can be designed, for example, as a filter cover, which is arranged on the floor of the painting booth, so that the booth air is sucked down through the filter cover out of the painting booth becomes.

Due to the greater application efficiency of the print heads used as application devices within the scope of the invention and the lower overspray, the air speed in the painting booth can be lower than in conventional painting systems that use, for example, rotary atomizers as application devices. In the paint shop according to the invention, the air speed in the paint booth can therefore be less than 0.5 m / s, 0.4 m / s, 0.3 m / s, 0.2 m / s or 0.1 m / s.

In a variant of the invention, at least one color changer is assigned to the print head, which is connected to the print head on the output side and is supplied with different coating agents on the input side, so that the color changer selects one of the coating agents and feeds the print head with the selected coating agent. The color changer is preferably supplied with various coating agents in the basic colors of a color system (e.g. the CMYK color system) so that a desired color can be mixed together from the differently colored coating agents.

In addition, the color changer can be supplied with various effect paints on the input side, such as special paints, metallic paints or mica paints.

It can be advantageous here if the color changer supplies only a single coating agent nozzle of the print head with the selected coating agent. In a variant of the invention, each coating agent nozzle of the print head is assigned a separate color changer, so that the coating agent to be applied can be selected individually for the individual coating agent nozzles.

The individual color changers can preferably be controlled independently of one another and individually in order to select the desired coating agent for the respective coating agent nozzles.

In another exemplary embodiment of the invention, the color changer feeds a group of several coating agent nozzles with the same coating agent on the output side, the coating agent nozzles, for example, in one Row can be arranged, for example in a row or a column.

Furthermore, there is the possibility that a color mixer is arranged upstream of the color changer on the input side, which is supplied on the input side with different colored coating agents in the basic colors of a color system (e.g. CMYK color system). The color mixer can then mix a desired color tone from the various basic colors of the respective color system and feed it to the color changer for selection. Furthermore, in this exemplary embodiment, the color changer is preferably supplied with at least one effect paint, for example a mica paint, a metallic paint and / or a special paint. The color changer can then either select the color tone mixed together by the color mixer or access one of the effect lacquers.

In another exemplary embodiment of the invention, a group of adjacent coating agent nozzles is each supplied with a basic color of a color system. For example, four adjacent coating agent nozzles can be supplied with the basic colors cyan, magenta, yellow or black. In this exemplary embodiment, a further adjacent coating agent nozzle is then supplied with one of several effect paints by a color changer. The coating agent nozzles for the basic colors and for the effect paint are here arranged spatially so closely adjacent in the print head that the ejected coating agents on the component to be coated mix to a desired color shade with a desired effect paint. In this exemplary embodiment, color mixing takes place on the component to be coated.

It has already been mentioned above that the coating agent nozzles in the print head can be arranged in rows, for example in rows and columns. The coating agent nozzles are therefore preferably arranged in the form of a matrix in the print head.

Here, within the scope of the invention, there is the possibility that a basic color (e.g. cyan, magenta, yellow, black) is assigned to the individual rows of coating agents, so that the coating agent nozzles in a row apply the same color. There is also the option of supplying the coating agent nozzles within a row of nozzles alternately with the respective basic color (e.g. cyan, magenta, yellow, black) and with an effect paint.

There is also the possibility that the individual rows of nozzles are each supplied with the coating agent to be applied by a color changer, the color changers in each row of nozzles being supplied with a specific base color and with an effect paint. For example, the color changer of one row of nozzles can be supplied with a coating agent of the color cyan and a special varnish, while the color changer of the next row of nozzles is supplied with a coating agent of the color magenta and the special varnish. With a CMYK color system, the color changers in the next row of nozzles are then supplied with the colors yellow or black and the special color.

In addition, there is the possibility that the color changers of the individual rows of nozzles are connected on the inlet side together with another color changer that selects one of several effect paints. The color changers in the individual rows of nozzles can then either use the directly supplied basic color or access the special colors supplied indirectly via the additional color changer.

In another exemplary embodiment of the invention, a group of coating agent nozzles is jointly supplied with a specific color tone via a color mixer, which is mixed together from the basic colors of a color system by the color mixer. In contrast, in this exemplary embodiment, an adjacent further coating agent nozzle is supplied with another color changer that selects one of several effect paints. Here, too, the selected effect paint is mixed with the previously mixed color on the component to be coated.

In another exemplary embodiment of the invention, some of the coating agent nozzles of the print head are jointly connected to a color mixer, which is supplied on the input side with the primary colors of a color system. In contrast, another part of the coating agent nozzles of the print head is connected here together with a special color supply. Here, too, the coating agent nozzles are preferably arranged in the form of a matrix in the print head in rows and columns. There is the possibility that the coating agent nozzles in the individual nozzle rows (rows or columns) are alternately connected to the paint mixer and the special paint supply.

In addition, within the scope of the invention there is also the possibility that all coating agent nozzles of the pressure head, or at least a large part thereof, are jointly connected to a single coating agent feed line and therefore apply the same coating agent.

Alternatively, within the scope of the invention, there is the possibility that part of the coating agent nozzles of the print head is connected to a first coating agent feed line, while a second part of the coating agent nozzles of the print head is connected to a second coating agent feed line so that the print head can apply two different coating agents. The coating agent nozzles in the individual rows of nozzles (rows or columns) are in this case alternately connected to one coating agent feed line or to the other coating agent feed line.

In one embodiment of the invention, the pressure head has at least one separate coating agent nozzle, which only applies effect paint with effect particles contained therein. In addition, the print head then preferably has at least one further coating agent nozzle that applies normal lacquer that does not contain any effect particles. The various coating agent nozzles can then be adapted accordingly.

It is also conceivable that in the color mixing process described above, the effect particles (e.g. metallic, mica, etc.) are applied to the object with a separate coating agent nozzle. This means that effects can be applied to the object in a targeted manner and with local differences. Under certain circumstances, effects can also be created that are inconceivable today. With the new inkjet technology it is possible to add effect particles e.g. just to place on the surface of the layer.

Furthermore, it is a major main advantage of the invention that with the solution according to the invention it is possible for the first time to have a complete body with sufficient area coverage to coat, but also to print specific details and graphics.

It has already been mentioned above that the coating agent nozzles in the print head are preferably arranged in the form of a matrix in several rows and columns. In a variant of the invention, the individual coating agent nozzles of the print head are essentially the same size. The adjacent rows of nozzles can be arranged offset from one another in the longitudinal direction, in particular by half a nozzle width, which enables a maximum packing density of the coating agent nozzles in the nozzle head. In addition, the individual rows of nozzles are preferably aligned transversely, in particular at right angles to the direction of advance of the nozzle head.

In another embodiment of the invention, the printhead has nozzle openings of different sizes. Thus, for example, rows of nozzles with large coating agent nozzles and rows of nozzles with small coating agent nozzles can be arranged alternately in the print head. Here, too, it can be useful if the rows of nozzles with the larger coating agent nozzles are arranged offset relative to one another, in particular by half a nozzle width.

In another variant of the invention, the print head is rotatably mounted and rotates during the coating. Here, too, the print head can have coating agent nozzles of different sizes, the smaller coating agent nozzles preferably being arranged closer to the axis of rotation of the print head than the larger coating agent nozzles.

In another variant of the invention, several print heads are provided, which are shared by a device (eg multi-axis robots) and are pivotable relative to each other, which allows adaptation to curved component surfaces.

It has already been mentioned above that, within the scope of the invention, different basic colors of a color system can be mixed in order to obtain a desired color shade, with the color mixing optionally taking place in a color mixer or on the component surface to be coated. The color system can be either the CMYK color system or the RGB color system, to name just a few examples. However, with regard to the color system used, the invention is not restricted to the examples given above.

Furthermore, it has already been mentioned above that, for example, a special paint, a metallic paint or a mica paint can be used as the effect paint.

Furthermore, it can be advantageous to provide the surface areas of the pressure head (e.g. lines) coming into contact with the coating agent at least partially with a wear-reducing coating, such as a DLC coating (DLC: Diamond-like Carbon), a diamond coating, a hard metal or a material combination of a hard and a soft material. Furthermore, the surface areas of the print head that come into contact with the coating agent can be coated with titanium nitride, titanium oxide or chemical nickel or with another layer that is formed in the PVC process (PVC: Physical Vapor Deposition), in the CVD process (CVD: Chemical Vapor Deposition ) or in the anodizing process (anodizing: electrolytic oxidation of aluminum) or provided with an "easy-to-clean" coating.

Furthermore, an electrostatic coating agent charge and / or compressed air support can be provided to improve the application efficiency wheel of the print head.

Another possibility is a position detection, which detects the spatial position of the print head and / or the component surface to be coated and controls or regulates the positioning of the print head accordingly.

Efforts are currently being made to mix automotive paints directly in the paint shops from 6-10 base pastes. For this purpose, the pastes are mixed in the conventional way in mixing stations and the color tones are set. All paints used in the automotive industry (uni, metallic and mica or effect paints) can be produced from these pastes. It is conceivable that these pastes are mixed directly in the atomizer or an upstream device. This has the advantage that only the required amount is made available fully automatically directly before or during the application. The dosing of the individual components can be done with the known dosing techniques (pressure regulators, dosing pumps, gear measuring cells, flow measuring cells, piston dosing devices, ...). The "mixing space" can be a mixing chamber, a piece of tubing or a mixing system (e.g. Keenix mixer). The problem is the very precise dosage of the individual components in order to achieve the exact shade. A color sensor can therefore be useful to control the dosing unit.

However, inkjet technology can also be used as the metering technology. The required amount can be generated from individual droplets, which are dependent on the opening time of the nozzle and the pressure. These inkjet nozzles mix the color in turn in a mixing room.

Furthermore, within the scope of the invention there is the possibility that a sensor is provided which detects the course of a guide track in order to position the print head in relation to the guide track.

In a preferred embodiment, the sensor is attached to the print head or to the robot, but other designs are also possible in principle. For example, the sensor can detect the previous painting path so that the current painting path can be applied in a certain relative position relative to the previous painting path. It is therefore generally desirable for the current painting path to be applied at a certain distance parallel to the previous painting path, which is possible using the sensor detection described above.

In the preferred exemplary embodiment, the sensor is an optical sensor, but other types of sensors are also possible in principle.

The guide track mentioned above can also be a separate track applied for guiding purposes only and, for example, may comprise a normally invisible paint that is only visible to the sensor when illuminated with ultraviolet (UV) or infrared (IR) light.

In this context, there is also the possibility of using a laser measurement system, as is known per se from the prior art. Such a laser measuring system can also detect the distance to the surface of the component to be coated and keep it constant within the framework of a regulation. In this variant of the invention, a robot controller is provided which is connected on the input side to the sensor and on the output side to the robot, the robot controller positioning the print head as a function of the course of the guideway.

In a variant of the invention, the print head has a sheath flow nozzle which emits a sheath flow of air or another gas, the sheath flow enveloping the coating agent flow released from the coating agent nozzle in order to atomize or delimit the coating agent droplets. In addition, this enveloping flow in the form of an air curtain can direct the resulting overspray onto the component surface, thereby improving the application efficiency.

In one embodiment of the invention, the pressure head has several coating agent nozzles which are arranged next to one another with respect to the web direction, the outer coating agent nozzles emitting less coating agent than the inner coating agent nozzles, which leads to a corresponding layer thickness distribution transversely to the web direction. Nozzles do not necessarily have to be arranged in a row. The amount of paint can be controlled for each nozzle and each pixel. By different amounts of color z. B. also controlled the hue intensity. There is the possibility that the layer thickness distribution is a Gaussian normal distribution. Alternatively, there is the possibility that the amount of coating agent released by the individual coating agent nozzles is selected such that the layer thickness distribution is a trapezoidal distribution. Such a trapezoidal layer thickness distribution is advantageous because the adjacent coating agent webs can overlap one another in such a way that the trapezoidal ones are superimposed Layer thickness distributions of the adjacent coating agent webs lead to a constant layer thickness.

In another exemplary embodiment of the invention, the components to be coated are conveyed along a conveying path, which is known per se from the prior art of painting systems and therefore does not need to be described in more detail. In this exemplary embodiment, a portal spans the conveying path, numerous print heads being attached to the portal, which are directed at the components on the conveying path and coat these components.

It should also be mentioned that the coating agent is preferably applied to the component in the form of pixels, the individual pixels each consisting of several basic colors of a color system in order to achieve a desired color shade of the pixel by color mixing. The color mixing can be, for example, a subtractive color mixing, but it is in principle also possible to achieve the desired color tone by an additive color mixing. The different basic colors (e.g. red, green, blue) of the respective color system (e.g. RGB color system) are arranged in layers one above the other in the individual pixels. With such a pixel-shaped application of the coating agent, there is the possibility that the top layer of each pixel has an effect lacquer and is semi-transparent, so that the top layer achieves the desired effect and at the same time lets through the desired color that is generated by the layers below.

Finally, the invention also includes a corresponding coating method, as can already be seen from the description above.

Figur 1

eine Querschnittsansicht durch eine herkömmliche Lackieranlage zur Lackierung von Kraftfahrzeugkarosseriebauteilen,

Figur 2

eine Querschnittsansicht durch eine erfindungsgemäße Lackieranlage zur Lackierung von Kraftfahrzeugkarosseriebauteilen mit Druccköpfen als Applikationsgeräte,

Figur 3A

eine Düse des Druckkopfs mit einem Farbwechsler und der zugehörigen Beschichtungsmittelversorgung,

Figur 3B

eine Düsenreihe des Druckkopfs mit mehreren Beschichtungsmitteldüsen und jeweils individuell zugeordneten Farbwechslern,

Figur 4A

eine Düsenreihe mit mehreren Beschichtungsmitteldüsen und einem zugeordneten Farbwechsler

Figur 4B

eine Abwandlung von Figur 4A, wobei der Farbwechsler eingangsseitig nur eine einzige Sonderfarbversorgung aufweist,

Figur 5

eine Abwandlung von Figur 4A, wobei der Farbwechsler eingangsseitig mit einem Farbmischer verbunden ist, der mit den Grundfarben eines Farbsystems versorgt wird,

Figur 6

eine Düsenreihe des Druckkopfs mit mehreren Beschichtungsmitteldüsen, wobei vier der Beschichtungsmitteldüsen jeweils mit einer Grundfarbe eines CMYK-Farbsystems gespeist werden, während die fünfte Beschichtungsmitteldüse von einem Farbwechsler mit einem Effektlack gespeist wird,

Figur 7

mehrere Düsenreihen des Druckkopfs, denen jeweils eine Grundfarbe eines CMYK-Farbsystems zugeordnet ist,

Figur 8

mehrere Düsenreihen des Druckkopfs, denen jeweils ein Farbwechsler und jeweils eine Grundfarbe eines CMYK-Farbsystems zugeordnet ist,

Figur 9

mehrere Düsenreihen des Druckkopfs, denen jeweils eine Grundfarbe eines CMYK-Farbsystems und ein Farbwechsler zugeordnet ist, wobei die Düsenreihen alternativ über einen weiteren Farbwechsler mit einem Effektlack versorgt werden können,

Figur 10

eine Düsenreihe des Druckkopfs, wobei vier benachbarte Beschichtungsmitteldüsen über einen Farbmischer mit einem gemischten Farbton versorgt werden, während die fünfte Beschichtungsmitteldüse über einen Farbwechsler einem Effektlack versorgt wird,

Figur 11

mehrere Düsenreihen des Druckkopfs, die gemeinsam über einen Farbmischer mit einem Mischfarbton versorgt werden,

Figur 12

mehrere Düsenreihen des Druckkopfs mit jeweils einem Farbwechsler, wobei die Farbwechsler der einzelnen Düsenreihen über einen Farbmischer mit einem Farbmischton versorgt werden,

Figur 13

mehrere Düsenreihen des Druckkopfs, die gemeinsam über einen Farbwechsler und einen Farbmischer mit dem zu applizierenden Beschichtungsmittel versorgt werden,

Figur 14

mehrere Düsenreihen des Druckkopfs, die gemeinsam über eine einzige Beschichtungsmittelzuleitung versorgt werden,

Figur 15

mehrere Düsenreihen des Druckkopfs, wobei die einzelnen Düsen innerhalb der Düsenreihen abwechselnd mit einer ersten Beschichtungsmittelzuleitung und einer zweiten Beschichtungsmittelzuleitung verbunden sind,

Figur 16

eine Düsenanordnung in einem Druckkopf,

Figur 17

eine alternative Düsenanordnung in dem Druckkopf mit kleineren Beschichtungsmitteldüsen,

Figur 18

eine alternative Anordnung der Beschichtungsmitteldüsen in dem Druckkopf, wobei die Beschichtungsmitteldüsen unterschiedliche Düsengrößen aufweisen,

Figur 19

eine Abwandlung von Figur 18, wobei die Düsenreihen mit den größeren Beschichtungsmitteldüsen versetzt zueinander angeordnet sind,

Figur 20

ein Schema zur Verdeutlichung der Lackierung einer scharfen Kante mit dem erfindungsgemäßen Druckkopf,

Figur 21

einen rotierenden Druckkopf,

Figur 22

eine Druckkopfanordnung mit mehreren verschwenkbaren Druckköpfen zur Anpassung an gekrümmte Bauteiloberflächen,

Figur 23

ein schichtförmig aufgebautes Pixel mit mehreren Schichten in den Grundfarben eines Farbsystems und einer obersten Schicht aus einem Metalliclack,

Figur 24

eine schematische Darstellung einer erfindungsgemäßen Beschichtungseinrichtung mit einem mehrachsigen Roboter, der einen Drucckopf und einen Sensor führt, um den Drucckopf zu positionieren,

Figur 25

eine schematische Darstellung einer erfindungsgemäßen Beschichtungseinrichtung, bei der mehrere Komponenten zu einem Gemisch zusammengemischt werden, wobei der Druckkopf dann das Gemisch appliziert,

Figur 26

eine schematische Darstellung eines erfindungsgemäßen Druckkopfs, der mehrere Komponenten unabhängig voneinander appliziert, wobei die Mischung auf der Bauteiloberfläche erfolgt,

Figur 27

eine schematische Darstellung eines erfindungsgemäßen Druckkopfs mit einer Hüllstromdüse,

Figur 28

eine schematische Darstellung eines erfindungsgemäßen Druckkopfs, bei dem die Beschichtungsmitteltropfen pneumatisch ausgestoßen und beschleunigt werden,

Figur 29

eine schematische Darstellung eins Drucckopfs, der eine trapezförmige Schichtdickenverteilung erzeugt,

Figur 30

eine schematische Darstellung einer erfindungsgemäßen Beschichtungseinrichtung, bei der zahlreiche Druckköpfe an einem Portal angebracht sind,

Figur 31 und 32

Abwandlungen der Figuren 18 und 19 mit einer maximalen Packungsdichte der einzelnen Düsen.

The technology according to the invention can also be used for the targeted coating of cut edges of pre-coated metal sheets, punched plates or for the efficient sealing of seams and edges
Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred exemplary embodiments of the invention with reference to the figures. Show it:

Figure 1

a cross-sectional view through a conventional paint shop for painting motor vehicle body components,

Figure 2

a cross-sectional view through a painting system according to the invention for painting motor vehicle body components with pressure heads as application devices,

Figure 3A

a nozzle of the print head with a color changer and the associated coating agent supply,

Figure 3B

a row of nozzles of the printhead with several coating agent nozzles and each individually assigned color changer,

Figure 4A

a row of nozzles with several coating agent nozzles and an associated color changer

Figure 4B

a variation of Figure 4A whereby the color changer has only one special color supply on the input side,

Figure 5

a variation of Figure 4A The color changer is connected on the input side to a color mixer that is supplied with the primary colors of a color system,

Figure 6

a row of nozzles of the print head with several coating agent nozzles, whereby four of the coating agent nozzles are each fed with a basic color of a CMYK color system, while the fifth coating agent nozzle is fed by a color changer with an effect paint,

Figure 7

several rows of nozzles of the printhead, each of which is assigned a basic color of a CMYK color system,

Figure 8

several rows of nozzles of the print head, each of which is assigned a color changer and a basic color of a CMYK color system,

Figure 9

Several rows of nozzles of the printhead, each of which is assigned a basic color of a CMYK color system and a color changer, whereby the rows of nozzles can alternatively be supplied with an effect varnish via another color changer,

Figure 10

a row of nozzles of the printhead, whereby four adjacent coating agent nozzles are supplied with a mixed color shade via a color mixer, while the fifth coating agent nozzle is supplied with an effect paint via a color changer,

Figure 11

several rows of nozzles of the printhead, which are jointly supplied with a mixed color via a color mixer,

Figure 12

Several rows of nozzles of the printhead, each with a color changer, whereby the color changers of the individual rows of nozzles are supplied with a color mixture via a color mixer,

Figure 13

several rows of nozzles of the print head, which are jointly supplied with the coating agent to be applied via a color changer and a color mixer,

Figure 14

several rows of nozzles of the print head, which are jointly supplied via a single coating agent feed line,

Figure 15

several rows of nozzles of the printhead, the individual nozzles within the rows of nozzles being alternately connected to a first coating agent feed line and a second coating agent feed line,

Figure 16

a nozzle arrangement in a print head,

Figure 17

an alternative nozzle arrangement in the print head with smaller coating agent nozzles,

Figure 18

an alternative arrangement of the coating agent nozzles in the print head, the coating agent nozzles having different nozzle sizes,

Figure 19

a variation of Figure 18 The rows of nozzles with the larger coating agent nozzles are offset from one another,

Figure 20

a scheme to illustrate the painting of a sharp edge with the print head according to the invention,

Figure 21

a rotating printhead,

Figure 22

a printhead arrangement with several pivotable printheads for adaptation to curved component surfaces,

Figure 23

a layered pixel with several layers in the basic colors of a color system and a top layer of a metallic paint,

Figure 24

a schematic representation of a coating device according to the invention with a multi-axis robot, which guides a pressure head and a sensor to position the pressure head,

Figure 25

a schematic representation of a coating device according to the invention, in which several components are mixed together to form a mixture, the print head then applying the mixture,

Figure 26

a schematic representation of a print head according to the invention, which applies several components independently of one another, the mixing taking place on the component surface,

Figure 27

a schematic representation of a print head according to the invention with a sheath flow nozzle,

Figure 28

a schematic representation of a print head according to the invention, in which the coating agent drops are pneumatically ejected and accelerated,

Figure 29

a schematic representation of a pressure head that generates a trapezoidal layer thickness distribution,

Figure 30

a schematic representation of a coating device according to the invention, in which numerous print heads are attached to a portal,

Figures 31 and 32

Variations of the Figures 18 and 19th with a maximum packing density of the individual nozzles.

The cross-sectional view in Figure 2 shows a painting system according to the invention, which is partially with the initially described and in Figure 1 conventional painting system shown corresponds, so that to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of the painting system according to the invention is first of all that the painting robots 3, 4 do not use rotary atomizers as application devices, but print heads 8, 9, which have a much greater application efficiency of more than 95% and therefore generate significantly less overspray.

On the one hand, this offers the advantage that in the conventional painting system according to Figure 1 existing washout 7 can be dispensed with.

Instead, in the paint shop according to the invention, there is an air suction device 10 under the paint booth 2, which sucks the booth air down through a filter ceiling 11 from the paint booth 2. The filter ceiling 11 filters out the overspray that is slightly present in the booth air, without the need for washing 7 as in the conventional painting system.

The print heads 8, 9 in this embodiment work like conventional print heads according to the piezo principle, but the surface coating performance of the print heads 8, 9 significantly larger in comparison to conventional print heads, so that the motor vehicle body components can be painted at a satisfactory operating speed.

Figure 3A shows a coating agent nozzle 12 which is arranged in each of the print heads 8, 9 next to numerous other coating agent nozzles, the coating agent nozzle 12 being supplied with the coating agent to be applied by a color changer 13. On the input side, the color changer 13 is connected to a total of seven coating agent feed lines, of which the color changer 13 can select one for supplying the coating agent to the coating agent nozzle 12. Four coating agent supply lines of the color changer 13 are used to supply differently colored coating agents in the basic colors C (cyan), M (magenta), Y (yellow = yellow) and K (key = black). The other three coating agent feed lines of the color changer 13, on the other hand, serve to supply a metallic paint, a mica paint and a special paint.

In this exemplary embodiment, the desired color shade of the coating agent is mixed on the motor vehicle body component to be coated, with either temporal or local mixing being possible.

In the case of temporal mixing, for example, coating agent droplets in the basic colors C, M, Y and K are applied successively in the desired color ratio, so that the coating agent droplets then mix on the motor vehicle body component to be coated.

In the case of a local mixture, on the other hand, coating agent droplets of a certain basic color C, M, Y or K are applied from the coating agent nozzle 12, which then dissolve Mix on the motor vehicle body components to be coated with other coating agent droplets which are applied from another coating agent nozzle, not shown here.

Figure 3B shows a modification of the embodiment according to Figure 3A , wherein a row of nozzles with four coating agent nozzles 14.1-14.4 and four color changers 15.1-15.4 is shown.

The color changers 15.1-15.4 are jointly connected to five coating agent feed lines via which the color changers 15.1-15.4 are supplied with the four basic colors C, M, Y, K of the CMYK color system and also with a special varnish S.

Figure 4A shows a group of coating agent nozzles 16.1-16.5, which are connected together with the output of a color changer 17 and therefore apply the same coating agent during operation.

The color changer 17 is connected on the input side to seven coating agent feed lines, four of the coating agent feed lines supplying the basic colors C, M, Y, K of the CMYK color system, while the other three coating agent supply lines supply a metallic paint, a mica paint or a special paint.

The embodiment according to Figure 4B largely agrees with that described above and in Figure 4A illustrated embodiment, so that to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this embodiment is first of all that the color changer 17 is connected on the output side to a total of six coating agent nozzles 16.1-16.6, which thus apply the same coating agent.

Another special feature of this embodiment is that the input side of the color changer 17 is only connected to five coating agent feed lines, four of the coating agent feed lines supplying the basic colors C, M, Y, K of the CMYK color system, whereas the fifth coating agent supply line is supplying a special paint.

The embodiment according to Figure 5 partly agrees with the embodiment according to Figure 4A agree, so that to avoid repetition reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this exemplary embodiment is that the color changer 17 is connected on the input side to a color mixer 18, the color mixer 18 being connected on the input side to four coating agent supply lines which supply the four basic colors C, M, Y, K of the CMYK color system. The color mixer 18 can therefore mix any color tone from the four basic colors C, M, Y, K and feed it to the color changer 17.

Furthermore, it can be seen from the drawing that the color changer 17 can optionally only supply the coating agent nozzle 16.1 with the coating agent to be applied or optionally also the coating agent nozzles 16.2, 16.3 and possibly also other coating agent nozzles that are not shown in the drawing.

The embodiment according to Figure 6 again partially corresponds to the exemplary embodiments described above, so that reference is made to the above description to avoid repetition, the same reference symbols being used for corresponding details.

A special feature of this exemplary embodiment is that the adjacent coating agent nozzles 16.1-16.4 are each connected directly to a coating agent feed line via which one of the basic colors C, M, Y, K of the CMYK color system is supplied.

The adjacent coating agent nozzle 16.5, on the other hand, is connected via the color changer 17 to three further coating agent feed lines that supply a metallic paint, a mica paint or a special paint.

During operation, the color changer then selects the desired effect paint (metallic paint, mica paint or special paint) and applies it via the coating agent nozzle 16.5. In addition, the four basic colors C, M, Y and K of the CMYK color system are applied in the desired ratio via the coating agent nozzles 16.1-16.4. On the component to be coated, the basic colors C, M, Y, K mix with the selected effect paint.

Figure 7 shows several rows of nozzles 19.1-19.4 with numerous coating agent nozzles 20, each of the rows of nozzles 19.1-19.4 being assigned one of the four primary colors C, M, Y, K of the CMYK color system. The coating agent nozzles 20 of the coating agent row 19.1 apply the basic color C (cyan), while the coating agent row 19.2 applies the basic color M (magenta). The coating agent nozzles 20 of the row of nozzles 19.3, on the other hand, apply coating agents of the basic color Y (yellow), while the coating agent nozzles 20 of the row of nozzles 19.4 apply coating agents of the basic color K (key = black).

In addition, the rows of nozzles 19.1-19.4 can also apply a special lacquer S. In the individual rows of nozzles 19.1-19.4, every second of the coating agent nozzles 20 is therefore connected to a special paint supply line. In the individual rows of nozzles 19.1-19.4, the individual coating agent nozzles 20 can thus alternately apply the special lacquer S and one of the four basic colors C, M, Y, K.

Figure 8 likewise shows four rows of nozzles 21.1-21.4, each of which includes numerous coating agent nozzles 22.

Furthermore, four color changers 23.1-23.4 are provided, each of which supplies all coating agent nozzles 22 of one of the four rows of nozzles 21.1-21.4 with a coating agent. Thus, the color changer 23.1 feeds all coating agent nozzles 22 of the nozzle row 21.1, while the color changer 23.2 feeds all coating agent nozzles 22 of the nozzle row 21.2. The color changer 23.3, on the other hand, feeds all coating agent nozzles 22 of the nozzle row 21.3, while the color changer 23.4 supplies all coating agent nozzles 20 of the nozzle row 21.4 with the coating agent to be applied.

On the input side, the color changers 23.1-23.4 are each supplied with a basic color C, M, Y, K, so that each of the basic colors C, M, Y, K is assigned to one of the four rows of nozzles 21.1-21.4. In addition, the color changers 23.1-23.4 are connected to several special color feed lines via which special colors, Metallic paints or the like can be supplied.

With this nozzle arrangement, too, there is color mixing on the component to be coated.

The embodiment according to Figure 9 partially agrees with that described above and in Figure 8 illustrated embodiment, so that to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this exemplary embodiment is that the color changers 23.1-23.4 are connected on the input side together with a further color changer 24, the color changer 24 being supplied with three different effect paints S1, S2, S3 on the input side. The color changer 24 thus selects one of the effect paints S1, S2 or S3 during operation and makes the selected effect paint available to the other color changers 23.1-23.4 for selection. The color changers 23.1-23.4 can therefore selectively select the respective basic color C. M, Y or K or the effect lacquer provided by the color changer 24.

The embodiment according to Figure 10 partly agrees with the embodiment according to Figure 6 agree, so that to avoid repetition reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this exemplary embodiment is that the coating agent nozzles 16.1-16.4 are not separated from one another with one of the basic colors C, M, Y or K, respectively are supplied. Rather, the coating agent nozzles 16.1-16.4 are jointly supplied with the coating agent to be applied by a paint mixer 25, the input side of the paint mixer 25 being supplied with the basic colors C, M, Y, K of the CMYK color system and mixing a desired color tone according to the control is then applied from the coating agent nozzles 16.1-16.4.

The embodiment according to Figure 11 partially agrees with that described above and in Figure 7 illustrated embodiment, so that to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this exemplary embodiment is that the individual rows of nozzles 19.1-19.4 are not supplied with different basic colors, but with a mixed coating agent that is mixed from the basic colors C, M, Y and K by a color mixer 26.

The embodiment according to Figure 12 partially agrees with that described above and in Figure 8 illustrated embodiment, so that to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this exemplary embodiment is that the individual color changers 23.1-23.4 are jointly supplied with a color mixture which is provided by a color mixer 27, the color mixer 27 being supplied with the primary colors C, M, Y and K on the input side.

Figure 13 shows a further embodiment of a nozzle arrangement in the print heads 8, 9, four rows of nozzles 28.1-28.4 being shown here, each of which has numerous coating agent nozzles 29. All of the coating agent nozzles 29 and all of the rows of coating agents 28.1-28.4 are jointly supplied with the same coating agent by a color changer 30.

On the input side, the color changer 30 is connected to three special color feed lines via which three special paints S1, S2, S3 are fed.

In addition, the color changer 30 is connected on the input side to a color mixer 31 which mixes a desired color tone from the basic colors, C, M, Y, K and provides the color changer 30 for selection.

The embodiment according to Figure 14 partially agrees with that described above and in Figure 13 illustrated embodiment, so that to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this exemplary embodiment is that all coating agent nozzles 29 in all nozzle rows 28.1-28.4 are connected to a common coating agent feed line 31 via which the same coating agent is fed.

The embodiment according to Figure 15 partly agrees with the embodiment according to Figure 11 agree so that for Avoid repetition, reference is made to the above description.

A special feature of this exemplary embodiment is that the coating agent nozzles 20 in the individual rows of nozzles 19.1-19.4 are alternately connected to a first coating agent line 32 and a second coating agent feed line 33.

Figure 16 shows a nozzle arrangement 34 for the print heads 8, 9 of the painting installation according to the invention, the arrow indicating the advance direction of the print heads 8, 9, ie the printing direction.

It can be seen from the drawing that the nozzle arrangement 34 has several rows of nozzles 35.1-35.7, each of which comprises several coating agent nozzles 36.

The coating agent nozzles 36 here have a uniformly large nozzle opening within the entire nozzle arrangement 34.

The adjacent rows of nozzles 35.1-35.7 are arranged offset from one another in the longitudinal direction, namely by half a nozzle width, which enables a maximum packing density of the coating agent nozzles 36 within the nozzle arrangement 34.

Figure 17 FIG. 3 shows a modified nozzle assembly 34 which is largely similar to that described above and in FIG Figure 16 corresponds to the nozzle arrangement shown, so that reference is made to the above description to avoid repetition.

A special feature of this exemplary embodiment is first of all that the individual nozzles 36 have a significantly smaller nozzle size.

Another special feature of this exemplary embodiment is that the adjacent rows of nozzles are not offset from one another.

Figure 18 shows a further embodiment of a nozzle arrangement 37 with five parallel rows of nozzles 38.1-38.5 with relatively large nozzle openings and four rows of nozzles 39.1-39.4 with relatively small nozzle openings.

The embodiment according to Figure 19 largely corresponds to the embodiment described above Figure 18 agree, so that to avoid repetition reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this exemplary embodiment is that the nozzle rows 38.1-38.5 with the larger nozzle openings are offset from one another in the longitudinal direction, namely by half a nozzle width.

Figure 20 shows a scheme for painting a sharp edge 39. It can be seen from this that the edge 39 is composed of differently sized coating agent surfaces 40, 41, 42, the differently sized coating agent surfaces 40-42 being produced by correspondingly differently sized coating agent nozzles.

When printing a graphic, larger areas of a color tone are printed with the large coating agent nozzles, whereas areas that require a certain edge sharpness are also printed small coating agent nozzles are refined. This process is particularly useful for two-tone paintwork (two-tone paintwork; e.g. sill area of a body in a contrasting color). The illustration shows an edge zone that is printed with three different nozzle sizes with sharp edges.

Figure 21 shows schematically a rotatable print head 43 with four large coating agent nozzles 44 and numerous smaller coating agent nozzles 45, the larger coating agent nozzles 44 being arranged on the outside with respect to the axis of rotation of the print head 43, while the smaller coating agent nozzles 45 are located on the inside with respect to the axis of rotation of the print head 43.

Finally shows Figure 22 a printhead arrangement 46 with a total of four printheads 47-50, which are pivotable relative to one another in order to enable better adaptation to the surface of a curved component 51.

Figure 23 shows a pixel 52 which can be printed onto a component 53 with the coating method according to the invention by means of a print head, the pixel 52 being shown individually in the drawing for the sake of simplicity. In practice, however, numerous pixels 52 are applied.

The pixel 52 consists of several layers 54-57 which are arranged one above the other.

The three lower layers 55-57 consist of the basic colors red, green and blue of the RGB color system. Alternatively, however, there is also the possibility that the lower layers consist of the basic colors of another color system, such as the CMYK color system. The one on top of the other Layers 55-57 lying on the ground then generate a certain color tone by subtractive color mixing.

The top layer, on the other hand, consists of a semi-transparent metallic lacquer in order to achieve a metallic effect. Figure 24 shows, in a greatly simplified form, a coating device according to the invention with a multi-axis robot 58 which moves a print head 59 along predetermined coating agent paths over a component surface 60, the robot 58 being controlled by a robot controller 61. The robot controller 61 controls the robot 58 in such a way that the print head 59 is guided in each case along predetermined coating agent paths over the component surface 60, the coating agent paths lying next to one another in a meandering manner.

A special feature here is that an optical sensor 62 is additionally attached to the pressure head 59, which detects the position and the course of the previous coating agent path during operation so that the current coating agent path can be precisely aligned with the previous coating agent path.

Figure 25 shows in a greatly simplified form a variant of a coating device according to the invention with three separate coating agent feeds 63-65, each of which feeds a component of the coating agent to be applied.

The coating agent feeds 63-65 are connected on the output side to a mixer 66, which mixes the individual components together to form a coating agent mixture, which is then fed to a print head 67. The mix of the different In this case, components of the coating agent take place before application by the print head 67.

Figure 26 shows, in a simplified form, a print head 68 which applies three different components of a coating agent separately from one another to the component surface, the individual components only being mixed on the component surface.

Figure 27 shows in schematic form a print head 69 for applying drops of coating agent 70 to a component surface 71.

The print head 69 here has a coating agent nozzle 72 from which the individual coating agent drops 70 are ejected pneumatically or in some other way.

In addition, the print head 69 has a sheath flow nozzle 73 which surrounds the coating agent nozzle 72 in an annular manner and emits an annular sheath flow which surrounds the individual drops 70 of coating agent.

On the one hand, this serves to atomize or delimit the individual drops of coating agent 70.

On the other hand, the sheath flow emitted by the sheath flow nozzle 73 directs any overspray in the direction of the component surface 71 and thereby improves the application efficiency.

Figure 28 shows in a likewise greatly simplified form a print head 69 according to the invention, which is partially connected to the print head 69 according to FIG Figure 27 corresponds, so that reference is made to the above description to avoid repetition the same reference numerals being used for corresponding details.

A special feature of this exemplary embodiment is that the individual coating agent drops 70 are pneumatically ejected from the coating agent nozzle 72, the coating agent drops 70 being accelerated pneumatically, which increases the maximum possible painting distance, since the individual coating agent drops 70 have a correspondingly greater genetic energy due to the pneumatic acceleration to have.

Figure 29 shows in a greatly simplified form a print head 74 during the application of two adjacent painting paths, the position of the print head 74 in the current painting path being denoted without an apostrophe, whereas the position of the print head 74 'in the previous painting path is marked with an apostrophe.

The print head 74 has several coating agent nozzles 75 which are arranged next to one another transversely to the web direction, the outer coating agent nozzles 75 emitting less coating agent than the inner coating agent nozzles 75. As a result, the printing head 74 generates a trapezoidal layer thickness distribution 76 on the component surface. This is advantageous because the trapezoidal layer thickness distribution 76 is then superimposed with the likewise trapezoidal layer thickness distribution 76 'of the preceding coating path, which leads to a constant layer thickness.

Figure 30 shows in simplified form a coating device according to the invention, in which the components 77 to be painted along a linear conveying path 78 through a painting booth be transported, which is known per se from the prior art and therefore does not need to be described in more detail.

The conveying path 78 is spanned by a portal 79, numerous print heads 80 being attached to the portal, which are directed at the components 77 on the conveying path 78 and coat them with a coating agent.

Figure 31 shows a modification of Figure 19 so that to avoid repetition, reference is made to the above description, the same reference symbols being used for corresponding details.

A special feature of this exemplary embodiment is the significantly greater packing density of the individual coating agent nozzles.

Figure 32 shows a modification of Figure 18 so that to avoid repetition, reference is made to the above description, the same reference symbols being used for corresponding details.

Here, too, the special feature is that the packing density of the individual coating agent nozzles is significantly greater.

The invention is not restricted to the preferred exemplary embodiments described above. Rather, a large number of variants and modifications are possible which also make use of the inventive concept and therefore fall within the scope of protection.

Claims (20)

1. Coating device for coating motor vehicle body parts with a multi-axis robot (3, 4, 58) having a multi-axis robot hand on which an application device is mounted applying the coating agent as coating agent paths,
   characterised in that the application device is a print head (8, 9, 59) which discharges the coating agent from a plurality of coating agent nozzles,
   and a position detection system is provided for detecting the spatial position of the print head (8, 9, 59) and/or the component surface to be coated, with a sensor (62) which detects the course of a guide path on the component surface (60) to be coated in order to position the print head with reference to the course of the guide path.
2. Coating device in accordance with claim 1, characterised in that the sensor (62) is positioned together with the print head (59) by the robot (58) and detects the course of a guide path on the component (60) to be coated, and a robot controller (61) is provided, which on the input side is connected to the sensor (62) and on the output side to the robot (58), whereby the robot controller (61) positions the print head (59) as a function of the course of the guide path.
3. Coating device in accordance with claim 2, characterised in that the sensor (62) is an optical sensor,
   and/or the guide path is a previously applied coating agent path, or
   the guide path contains a coating agent that is only visible when illuminated with UV light or IR light.
4. Coating device in accordance with claim 2 or 3, characterised in that the guide path is a previous coating agent path detected by the sensor (62) or a separate path which is applied for guiding purposes.
5. Coating device in accordance with any one of the preceding claims,
   characterised in that
   the print head (74) includes a plurality of coating agent nozzles (75) which are arranged next to each other in relation to the path direction and the outer coating agent nozzles (75) emit less coating agent than the inner coating agent nozzles (75).
6. Coating device in accordance with any one of the preceding claims,
   characterised in that the print head (74) applies a coating agent path with a layer thickness distribution (76) transversely to the path direction which is a trapezoidal distribution or a Gaussian normal distribution.
7. Coating device in accordance with any one of the preceding claims,
   characterised in that the coating agent nozzles (75) are arranged in a row.
8. Coating device in accordance with any one of the preceding claims,
   characterised in that the coating agent nozzles of the print head (8, 9) are jointly connected to a coating agent supply line via which the coating agent to be applied is supplied.
9. Coating device in accordance with any one of the preceding claims,
   characterised in that the print head (8, 9) exhibits an area coating performance of at least 1 m²/min, 2 m²/min, 3 m²/min, 4 m²/min or 5 m²/min.
10. Coating device in accordance with any one of the preceding claims with a painting cabin, characterised in that during operation the air downdraft speed in the painting cabin (2) is less than 0.3 m/s, 0.2 m/s, 0.1 m/s, 70 cm/s or 50 cm/s.
11. Coating device in accordance with any one of the preceding claims,
    characterised in that
    the coating agent is fluid paint and contains pigments, metallic flakes or other solid paint components, and
    the coating agent nozzles of the print head (8, 9) are large enough to apply the paint containing the solid paint components.
12. Coating device in accordance with any one of the preceding claims,
    characterised in that

    a) the print head (8, 9) is arranged in a painting cabin (2) in which the components are coated with the coating agent,

    b) no wash-out (7) is arranged under the painting cabin (2), which in conventional painting installations washes overspray out of the cabin air in the painting cabin (2),

    c) the coating device is not protected against explosion,

    d) an air extractor (10) is provided which extracts the cabin air from the painting cabin (2) downwards and/or through side channels, and /or

    e) an air filter (11) is provided which is arranged upstream of the air extractor (10) and filters the overspray from the cabin air, and the air filter (11) is designed as a filter cover which is arranged on the base of the painting cabin (2) so that the cabin air is extracted from the painting cabin (2) downwards through the filter cover (11).
13. Coating device in accordance with any one of the preceding claims,
    characterised in that the joint coating agent supply line is supplied by a colour changer.
14. Coating device in accordance with any one of the preceding claims,
    characterised in that

    a) the print head (8, 9, 43) is rotatably mounted about an axis of rotation and rotates during coating or between consecutive coating sessions, and/or

    b) the print head (8, 9, 43) has coating agent nozzles of different sizes, and/or

    c) the smaller coating agent nozzles (45) are arranged closer to the axis of rotation of the print head (8, 9, 43) than the larger coating agent nozzles (44).
15. Coating device in accordance with any one of the preceding claims,
    characterised in that a plurality of application devices are provided which are designed as print heads,
    and/or to coat curved component surfaces several print heads (47-50) are provided which preferably can swivel with regard to each other.
16. Coating device in accordance with any one of the preceding claims,
    characterised by an electrostatic coating agent charger and/or compressed air support to improve the application efficiency of the print head (8, 9).
17. Coating device in accordance with any one of the preceding claims,
    characterised in that the print head (69) has a sheath flow nozzle (73), the sheath flow nozzle (73) emits a sheath flow of air or another gas, and the sheath flow encompasses the coating agent emitted from the coating agent nozzle.
18. Coating method for coating motor vehicle body parts, the coating agent being applied as coating agent paths by a print head (8, 9, 59) which is mounted on the multi-axis robot hand of a multi-axis robot (3, 4, 58) and discharges the coating agent from a plurality of coating agent nozzles, characterised by the following steps:

    a) detecting of the spatial position of the print head (8, 9, 59) and/or the component surface (60) to be coated,

    b) control and/or regulation of the spatial position of the print head (8, 9, 59) as a function of the detected position, wherein the course of a guide path on the component surface (60) to be coated is detected by a sensor (62) in order to position the print head with reference to the guide path.
19. Coating method in accordance with claim 18, in which the coating agent nozzles (75) of the print head (8, 9) are arranged next to each other in relation to an applied coating agent path and the outer coating agent emitting less coating agent than the inner coating agent nozzles (75).
20. Coating method in accordance with claim 18 or 19, characterised in that the coating agent nozzles of the print head (8, 9) are jointly connected to a coating agent supply line via which the coating agent to be applied is supplied.

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