EP3411240B1 - Printing method and printing device - Google Patents

Description

The invention relates to a method and a device for printing a large area, in particular a large area located on a substrate that cannot be fed to a printing device. Examples of such surfaces are building walls, walls of trucks or railway wagons, surfaces on containers or even entire side walls of ships.

The FR 2 601 265 A1 describes such a method in which the print head is movably attached to a first axis along a printing path, the first axis being attached to a frame movable in the horizontal x-direction, and wherein the surface is printed by the sequential printing of the printing paths. The vertical distance of a reference point of the device is determined at several points distributed over the printing path to the surface to be printed and the vertical distance of the print head from the surface to be printed is set at the points distributed over the printing path according to a previously recorded measurement value. Similar processes are also shown by FR 2 735 420 A1 and the EP 2 644 392 A1 .

Large format printers have been known for many years. With such printers it is possible to print paper, but also other substrates with a width of up to 5m or even more and a theoretically endless length. The printing process takes place in one plane, i.e. two-dimensional, above a printing table. In these printers, the printing table is more or less linear, i. E. its extension in the width direction transversely to the feed direction of the substrate is significantly greater than in the substrate feed direction. Usually the substrate is rolled up on a roll and is fed to the printer, this feed covering the first axis of the two-dimensional printing process. A print head with a paint application system moves across the substrate at right angles to this axis. Inkjet printers are widespread, the color to be applied being an ink which spray ink drop by drop onto the substrate via nozzles that are controlled by a controller. Several nozzles for different colors can be arranged next to one another in the printhead, with which multicolor printing is possible. The printing plane usually corresponds to the horizontal. Because of the feed, the substrate must be flexible at least in the longitudinal direction.

Flatbed printers are also known. In such printers, the substrate is stretched in a bed, the printing table. The print head is attached to a cross table, which makes the print head itself in both directions Level is movable. With such flatbed printers it is possible to print on rigid substrates. The dimensions of such cross tables are finite and cannot be enlarged as desired, since the axes of the cross table can only be supported at their end points and must nevertheless have a minimum degree of stability. Even with flatbed printers, the substrate is fed to the printer.

In both systems, by feeding the substrate onto a printing table, the distance between the printing head in the spatial direction, i.e. orthogonal to the plane spanned by the x and y directions and here and below called the z direction, constant and precisely defined. This distance is important to get a clean print image. The ink nozzles are focused at this distance.

With either system, it is not possible to print on the surface of a non-moving substrate, for example the wall of a room or building.

In recent times, wall printers have become known with which it should be possible to print on walls. These printers use print heads from commercially available inkjet printers, which are attached to an axis so as to be movable in one direction, here and in the following named vertical direction or y-direction. This axis is fastened to a chassis, the chassis being movable in a direction essentially orthogonal to the vertical direction, here and hereinafter referred to as the horizontal direction or the x-direction. The printing principle corresponds to that of the large format printer described first: The vertical direction of the print head is realized by its up and down movement in the y-direction, while the horizontal direction is realized by the movement of the chassis in the x-direction. The printhead now prints a vertical path with an extension in the y-direction given by the printhead, i.e. with a web width in the horizontal direction. For printing on a web that is next to it in the horizontal direction, the chassis is moved past a wall in the x-direction while the print head remains in the upper or lower end position.

In practice, however, there are some problems: If the floor is not level, which is for example with tiled floors because of the joints between the tiles is usually the case, these unevenness are transferred into the print image. To solve this problem, known wall printers run on a rail system that bridges such unevenness. The disadvantage of this is that the rails have to be laid out and aligned, which means effort, and on the other hand long rails are required for long walls to be printed, which increases the cost of transporting the wall printer to a place of use, increases the costs for the wall printer and in turn the Increased printing effort.

Another problem with known wall printers is the limited height of the printable area: the y-axis consists of a profile of a finite length of usually 2 m, the print head movement along this axis taking place via a toothed belt. This means that the length of the y-axis cannot initially be extended, or can only be extended with great effort. In addition, the fastening and design of the stability of the y-axis is designed for this length, so that an extension of the axis would lead to a very unsatisfactory print image due to mechanical instability and associated fluctuations in the x and z directions of the y axis. Furthermore, the walls of buildings are rarely aligned exactly perpendicular to the ground, but are usually inclined relative to the ground. In most cases, the inclination is only small angular dimensions of a few degrees. Above a room height of usually around 2.50 m for residential buildings and significantly more for commercial buildings, however, a 1 ° inclination already makes a difference of more than 4 cm, which means that the print image is very different in terms of contour sharpness between the bottom end and the top end. In the prior art, it is known to use ultrasonic sensors to measure for subsequent tracking of the distance between the print head and the wall. These sensors are attached to the printhead and are therefore only able to detect the distance in real time, ie at the moment when the printhead is at the relevant point. A readjustment based on such a measurement can only be very imperfect because of the dead time between measurement and readjustment. Above this, a wall can also have unevenness that can destroy the printhead if it collides with them. The y-axes of known wall printers are more or less centrally mounted on the chassis in the x-direction, at least they are not mounted on an end of the chassis located in the x-axis. Thereby it is not possible to print into a corner. In other words, more or less wide, non-printable strips always remain in the corners of the room. The rails for the chassis can only be laid straight, ie it is not possible to print on curved surfaces. Also today it is only possible to print on areas that are perpendicular to the floor on which the chassis is running. It is not possible to print on differently oriented surfaces, for example ceiling or floor surfaces. It is especially not possible to print three-dimensionally shaped surfaces, for example vaulted ceilings. The object of the invention is therefore to provide a method for printing a large area, in particular a large area located on a substrate that cannot be fed to a printing device, which avoids the limitations and disadvantages described above. A further object of the invention is to specify a device for carrying out the method.

According to the invention, this object is achieved by a method having the features of independent claim 1. Advantageous developments of the method emerge from the subclaims 2-6. The object is also achieved by a device according to claim 7. Advantageous embodiments of the device emerge from the dependent claims 8-13.

The inventive method is suitable for printing a large area located on a substrate that cannot be fed to a printing device. , Areas such as the walls of buildings, trucks or railroad cars, areas on containers, etc., wherein the area to be printed can be divided into print paths in one direction according to the print width of a print head and the print head on a first axis along a print path in vertical y-direction is movably attached, the first axis is attached to a movable chassis in the horizontal x-direction and the surface is printed by the sequential printing of the vertical printing paths. In addition, the orthogonal distance A _z0 in the horizontal z-direction, which is orthogonal to the horizontal x-direction, of a reference point of the device at several points distributed over the vertical printing path to the surface to be printed is determined, and the orthogonal distance A _{z of} the print head of the area to be printed at the points distributed over the vertical printing path, corresponding to one previously recorded measurement value is set. The multiple points can be evenly distributed over the length of the vertical printing path. When deciding on the number of dots, the evenness of the surface to be printed and / or the expected number and extent of imperfections on the surface to be printed can be taken into account. In the case of a very flat surface without significant defects, a few points are sufficient; in the case of uneven surfaces with many defects, especially if at least some of these defects are large, many measurement points should be recorded. In the extreme case, the number of measuring points can be selected so large that a quasi-continuous measurement is available. The recorded measured values of each vertical print path are stored in series of measurements for each point measured along the print path, with a trend being determined from the measured values of at least one series of measurements, with a steering movement of the horizontally movable chassis being triggered when the trend exceeds a previously defined threshold exceeds. If the surface to be printed is, for example, a wall that is essentially perpendicular to the floor surface on which the horizontally movable chassis moves, for example a wall of a living room, a steering movement of the chassis is triggered when the distance between the wall and the chassis is approx The course of the movement of the chassis changed, for example because the wall direction bends or the wall describes a curve. According to the invention, the measured values of each measurement at a certain height are combined into series of measurements in the control device and a trend is calculated. If the trend of at least one measurement series changes above a previously defined threshold, the control device outputs a steering impulse to the chassis so that the distance of the chassis from the wall moves back into the previously defined corridor. In this way, it is also possible to print on walls that follow a curve or the course of which changes compared to a direction initially taken

The device for carrying out the method has a measuring device for contactless measurement of the distance between a reference point of the device and the surface to be printed. The device also has a control unit for evaluating the measured values and generating Control pulses for setting the distance A _{z of} the print head from the surface to be printed on.

With the setting of the distance A _{z of} the print head from the wall to be printed, the problems of the prior art with regard to a clearly contoured print image are solved despite the not exactly planar and equidistant alignment of the surface to be printed with respect to the print head. In order to be able to set the distance A _{z of} the print head at every location on the printing path so that it is always the same despite unevenness or, for example, non-perpendicular walls, the distance A _z must be determined. In a preferred embodiment, this is done without contact, preferably optically, for example with a laser range finder. Since the distance A _{z of} the print head from the surface to be printed is set so that it always has the same distance A _z , it cannot collide with an unevenness on this surface, for example. The measurement takes place via a reference point of the device. This reference point can be located, for example, on the first axis on which the print head is moved along a printing path. As a result, the reference point is moved together with the print head along a print path, so that the distance A _{z0 of} the reference point to the corresponding print head positions is known. The required print head position with regard to the distance A _z from the surface to be printed can be determined via the known geometric relationships of the device. A corresponding distance measuring device can be attached to the reference point. The reference point can be arranged in the horizontal x-direction next to the print head, so that the distance A _{z0 of} the reference point from the surface to be printed leads in one direction in _front of the print head during printing. This is the preferred direction of printing. By rushing ahead, the distance is already measured while the print head is still scanning the previous print path. This gives the control unit a lead time for calculating the printhead distance A _z from the surface to be printed.

In a preferred embodiment of the inventive method, at the beginning of a printing process, the first printing path is traversed without activating the print head, the orthogonal distance A _{z0 of} a reference point of the

Printhead is determined at several points distributed over the vertical printing path to the surface to be printed leading to the printing path traveled during the measurement. The print head travels the first path of the print image without printing. The print head for this travel is advantageously in a position as far away as possible from the surface to be printed. During this drive, only the distance measuring device is active. The recorded distances are sent to the control unit, where they are calculated for the position of the print head for a constant distance A _{z of} the print head from the wall for each location on the print path. Then the same printing path is traversed again, this time the print head is active and the area under the path is printed.

In an advantageous embodiment, the start position of the print head at the beginning of a print path is displayed optically. In a particularly advantageous embodiment, the starting position of the print head is displayed optically at the beginning of each print path. The print head has an optical display device for this purpose. This optical display device can be a laser lamp, for example. In particular, the optical display device can be a laser pointer. A laser pointer projects a point of light onto the substrate to be printed in a manner known per se and thus indicates where the print head is located. If this point is not identical to the point at which the print path begins, the print head can be readjusted accordingly.

It has proven to be advantageous if the printing is carried out by applying ink to the substrate, the ink being tempered to a temperature of approx. 43 ° C. The device has a corresponding temperature control device for this purpose. The printing takes place via an inkjet print head known per se, which can have several nozzles, for example for multi-color printing. The use of different inks is basically possible. In particular, if the surface to be printed is outside and exposed to weather conditions, it is advantageous to use a waterproof and UV-stable ink that can withstand rain and sunlight exposure for at least a certain period of time. Such inks can be optimally processed at a temperature of approx. 43 ° C possible processing temperature interval is approx. 1 K. It has proven to be advantageous if the ink is stored in bags and conveyed from bags, the bags being made of an aluminum alloy. In an advantageous embodiment, the ink bags are stored in the device on individual surface heating devices in the form of circuit boards, the heating power of the surface heating being regulated, the respective actual temperature of the surface heating being detected by a sensor and the information being fed to a regulating device. The aluminum alloy of the ink bags have good thermal conductivity, so that the ink temperature can be controlled very well via the temperature of the surface heating.

In a further advantageous embodiment, the print head is shaded from UV radiation by a device when it is not active. The device has a movable shading device for this purpose. Inks that have good water resistance and UV stability as well as good properties in terms of color brilliance and abrasion resistance are, for example, UV-curing. After the ink has been applied to the substrate, it cures under the influence of UV light, i.e. the monomers in the paint polymerize and the color pigments are fixed in the solid polymer layer. This should shade these inks from UV light as long as they have not yet been applied to the substrate. To this end, the device has a device, for example in the form of a slidably mounted plate, which can be pushed over the print head when it is inactive. If the print head has several nozzles, for example for different colors, the plate can have several openings which cover the different nozzles or open them again for printing after the plate has been moved. In one embodiment, the plate is a stainless steel sheet which has a possible travel path of, for example, 4 mm.

It is conceivable that the print head is pivoted depending on the orientation of the surface to be printed, so that the print head is always oriented essentially orthogonally to the surface to be printed. Walls of buildings can have projections or depressions, for example, the course of the wall extending at an angle in the direction of the projection or depression emotional. By pivoting the print head, it is also possible to print wall parts that run at an angle. In particular, it is also possible, for example, to print vaulted ceilings in which a wall extends continuously into a ceiling, ie an alignment pivoted essentially perpendicularly to the original alignment of the wall surface.

A device according to the invention for printing large areas, in particular those located on a substrate that cannot be fed to a printing device, such as walls of buildings, trucks or railway wagons, areas on containers, etc., in one direction in print paths corresponding to the print width of a print head, where the print head is movably attached to a first axis along a print path in the vertical y-direction, the first axis being attached to a chassis moveable in the horizontal x-direction, and wherein the surface is printable by the sequential printing of the vertical print paths, is thereby characterized in that the distance A _{z of} the printhead from the surface to be printed is adjustable according to the aforementioned method and the device has a measuring device for contactless measurement of the distance A _z0 between the reference point of the device and the surface to be printed and the Vorri It also has a control unit for evaluating the measured values and generating control pulses for setting the distance A _{z of} the print head from the surface to be printed.

The chassis can be moved in the horizontal x-direction, the chassis being designed to be steerable and the device also having a control unit for calculating the steering angle of the chassis. For this purpose, the recorded measured values of each print path for each point measured along the print path are stored in series of measurements and a trend is determined from the measured values of at least one series of measurements, with a steering movement of the horizontally movable chassis being changed if the trend exceeds a previously defined threshold.

It is conceivable that the print head is fastened so that it can be swiveled at least 180 ° about the horizontal on a third axis along a printing path. As the print head can be pivoted, it is possible to print on surfaces that are inclined in space. It is also possible to print on walls. Finally, it is even possible to print surfaces whose spatial orientation changes continuously, as is the case with vaults, for example.

In a further advantageous embodiment, the device has an extendable first axis for moving the print head along a printing path, the first axis having a toothed rack. By using a rack, the first axis can be easily extended by, for example, attaching a further axis module, also equipped with a rack, to the existing first axis. In one embodiment, a unit carrying the print head has a servomotor that drives a gear wheel that meshes with the rack of the first axis, whereby the unit carrying the print head can be moved very precisely and smoothly along the first axis, even if the first axis is extended is.

In a further advantageous embodiment, the device has a second axis for setting the distance A _{z of} the print head from the surface to be printed, the second axis having a spindle. The second axis is advantageously part of the unit that carries the printhead. It has proven to be advantageous if the spindle is driven by a servomotor. As a result, the distance A _{z of} the print head from the surface to be printed can be set very precisely and quickly.

The chassis has wheels with which it stands on a floor and can move in the horizontal x-direction. It has proven to be advantageous if the chassis has at least three, in particular four wheels, the wheels being arranged at its respective corners. Each wheel can have an adjustable height compensation. The chassis itself can have a measuring device with which the horizontal alignment of the chassis can be checked. In addition, the chassis can have a distance measuring device at its corners in the vicinity of the respective wheel. This is preferably implemented without contact, preferably as an optical measuring device. Furthermore, the chassis can have a control device that is dependent on the measurement results of each distance measuring device, the height compensation of each wheel can be activated so that the chassis levels itself at any time, especially if the floor is tiled, for example, and has deeper joints between the tiles. In addition, an activated height compensation of each wheel has an advantageous effect on the freedom from jerking of the horizontal movement of the chassis.

The device can have a device for displacing the print head in the direction or counter to the direction of movement of the chassis, in particular a third axis in this direction. This third axis can serve to move the print head to the end points or via the end points of the chassis in the direction of movement of the chassis. For example, if the area to be printed is a wall of a living room, it is possible with the aid of the third axis to print into the corners and to minimize or even close the areas of the wall that are not to be printed due to the necessary expansion of the chassis in the direction of movement eliminate.

The chassis is able to move forwards and backwards in the direction of movement. It also has a motor. This motor can be a stepper motor or a servo motor. One or more wheels can be driven for movement. The wheel or wheels can be driven directly or via a transmission, the wheel or wheels being able to be connected to the motor rigidly or via a transmission element, for example a chain or a belt, for example a toothed belt.

To implement the function of swiveling the print head, the alternatives are to swivel only the print head or to swivel a print head support unit consisting of the third axis with alignment in the direction of movement of the chassis together with the print head. Further advantages, special features and expedient developments of the invention emerge from the subclaims and the following illustration of preferred exemplary embodiments on the basis of the figures.

• Fig. 1 Eine erfindungsgemäße Vorrichtung in einer dreidimensionalen Prinzipskizze
• Fig. 2 Die erfindungsgemäße Vorrichtung in einer Draufsicht beim Bedrucken einer Wandfläche
• Fig. 3 Die erfindungsgemäße Vorrichtung in einer Draufsicht beim Bedrucken einer Wandfläche nahe einer Wandecke
• Fig. 4 zeigt einen erfindungsgemäßen Druckkopf 200 in einer Prinzipskizze

From the pictures shows:

• Fig. 1 A device according to the invention in a three-dimensional schematic diagram
• Fig. 2 The device according to the invention in a plan view when printing a wall surface
• Fig. 3 The device according to the invention in a plan view when printing a wall surface near a wall corner
• Fig. 4 shows a print head 200 according to the invention in a schematic diagram

Fig. 1 shows a device 100 according to the invention in a three-dimensional schematic diagram. The device 100 has a chassis 110 which can be moved on four wheels 111 in the horizontal x-direction on the floor 400. A distance measuring device (not shown) is provided at the corners of the chassis 110 in the vicinity of each wheel. This optically measures the distance to the ground 400 and forwards the measurement signal to a control device (not shown). Each wheel 111 has an adjustable height compensation (not shown). Depending on the measurement results of each distance measuring device, the height compensation of each wheel 111 can be activated so that the chassis 110 levels itself at any time, especially if the floor 400 is tiled, for example, and has deeper joints between the tiles. The device 100 also has a first axis 120 in the y direction. This first axle 120 has a toothed rack which is attached to the axle in the y direction. The first axis 120 can be designed in a standard industrial profile, with the rack being sunk and thus protected in the profile. The first axis 120 can be extended in that one or more axis modules, which can also be implemented in the standard industrial profile, are plugged onto the first axis. The attachable axis modules also have a rack.

For example, the first axis 120 in the non-extended version is approx. 2.50 m long, which means that it can be used in residential buildings with standard ceiling heights. If higher surfaces 300 are to be printed, for example in a commercial property or on an external facade, the first axis 120 can be extended with corresponding axis modules so that printing paths longer than 2.50 m can also be printed.

A second axis 130 with a main extent in the z-direction is attached to the first axis 120 via a slide 121. The slide 121 has a drive in the form of a servomotor and a gear wheel meshing with the rack of the first axis 120. As a result of the up and down movement that the second axis 130 and a print head 200 attached to the second axis 130 can exert, a print path can be traversed in the y direction by the print head 200 and printed. After completion of this printing path, the device 100 can be moved by a printing path width in the x-direction by means of the chassis 110, so that the next printing path can be printed. A measuring device 190 in the form of a laser rangefinder is attached to the slide 121. This measuring device emits a measuring beam 192 in the direction of the surface 300 to be printed, where it strikes a measuring point 191. The distance of the measuring device 190 from the surface 300 to be printed at this point 191 is recorded and sent as a reference _distance A _z0 to a control device of the device 100, where it is stored. The second axis 130 has a spindle. Another servomotor for driving the spindle is located in the carriage 121. By evaluating the reference point _distance A _z0 in the control unit, it is possible to _infer the current distance A _{z of} the print head 200 from the surface 300 to be printed. This distance can be set quickly and precisely to a previously determined setpoint value stored in the control unit via the servomotor and the spindle. As a result, the distance A _{z of} the print head from the surface to be printed can be set very precisely and quickly.

An axis head 131 is attached to the second axis 130 at the end directed towards the surface 300 to be printed. This axis head 131 in turn houses a servomotor, which has a third axis 140 with alignment in x-direction, ie the direction of movement of the chassis 110, drives. The print head 200 is fastened to this third axis 140 such that it can move in the x direction. The print head 200 can thus be moved in the x-direction independently of the movement of the chassis 110. This is advantageous if you want to print into a corner of the wall, with a non-printable area being minimized.

The third axle 140 is pivotably mounted on the axle head 131, the pivoting range being at least 180 °. As a result, the print head 200 can both be pivoted upwards, whereby, for example, a ceiling can be printed, and it can also be pivoted downwards, whereby the floor on which the chassis 110 is movably placed can be printed.

For the printing of a room ceiling, the second axis 130, together with the axis head 131, third axis 140 and print head 200, can be rotatably fastened in the carriage 121, the rotational movement being at least 90 °, so that the ceiling can be printed with a corresponding upward rotation is.

Fig. 2 shows the device 100 when printing a wall surface 300 in a plan view from above. At least two wheels 111 can be steered so that the chassis can also follow a curved wall. The device has a control unit for calculating the steering angle of the chassis 110. The recorded measured values A _z0 of each print path for each point measured along the print path are stored in series of measurements and a trend is determined from the measured values of at least one series of measurements, a steering movement of the horizontally movable chassis 110 being changed when the trend exceeds a previously defined threshold exceeds.

Fig 3 shows the device 100 during printing on a wall surface 300 in a plan view from above, the device 100 being located in a corner formed from two walls. The print head 200 is moved to the corner-side end of the third axis 140 in order to print into the corners and to minimize or even eliminate the areas of the wall 300 in the direction of movement of the chassis 100 that are not to be printed due to the necessary expansion of the chassis 100 in the direction of movement .

Fig. 4 shows a print head 200 according to the invention in a schematic diagram. The print head 200 has four nozzles 220 which are located behind a shading plate 210. The shading plate 210 has four slots 211, the shading plate 210 being mounted displaceably in a guide 212 in the y-direction so that the nozzles 220 can be shaded from UV radiation by the shading plate when the nozzles are inactive. Furthermore, the print head 200 has a laser pointer 230, with the aid of which the position of the print head 200 at the beginning of a print path on the substrate to be printed can be displayed. The print head 200 has circuit boards 240 which are arranged on a shelf one above the other inside the print head 200. The boards 240 have a temperature control device. Certain inks can be processed optimally at a temperature of approx. 43 ° C. The ink is stored and conveyed in bags, the bags being made of an aluminum alloy. The ink bags are stored in the print head 200 on individual surface heating devices which are arranged on the circuit boards 240.

List of reference symbols:

100

Device for printing on large, non-moving surfaces

110

chassis

111

wheel

120

first axis, y-axis

121

Sledge

130

second axis, z-axis

131

Axle head

140

third axis, x-axis

190

Measuring device

191

Measuring point

192

Measuring beam

200

Printhead

210

Shading plate

211

slot

212

guide

220

jet

230

Laser pointer

240

circuit board

300

surface to be printed on, wall

400

ground

Claims (13)

1. A method for printing a large surface (300), in particular for a surface which is located on a substrate which cannot be fed to a printing device and which can be divided in one direction into printing paths corresponding to the printing width of a print head (200), the print head (200) being mounted on a first axis (120) so as to be movable along a printing path in the vertical y-direction, wherein the first axle (120) is mounted on a chassis (110) movable in the horizontal x-direction, and wherein the surface (300) is printed by sequentially printing the vertical printing paths, wherein the orthogonal distance Az0 in the horizontal z-direction, which is orthogonal to the horizontal x-direction, of a reference point of the device is determined at a plurality of points distributed over the vertical printing path to the surface (300) to be printed and the orthogonal distance Az0 in the horizontal z-direction of the print head (200) from the surface (300) to be printed at the points distributed over the vertical printing path is set in each case in accordance with a previously recorded measured value, characterized in that the recorded measured values Az0 of each vertical printing path for each point measured along the printing path are combined in a control device at a specific height in the y-direction to form measurement series, wherein a trend is determined from the measured values of at least one measurement series, a steering movement of the chassis (110), which can be moved in the horizontal direction, being changed if the trend exceeds a previously defined threshold.
2. The method according to claim 1, characterized in that at the beginning of a printing process the first printing path is traversed without activating the print head (200), wherein the orthogonal distance Az0 of a reference point of the print head (200) at several points distributed over the vertical printing path to the surface (300) to be printed is determined in advance of the printing path traversed during the measurement.
3. The method according to claim 1 or 2, characterized in that the starting position of the print head (200) at the beginning of a printing path is optically indicated.
4. The method according to one of the previous claims, characterized in that the print head (200) is pivoted depending on the orientation of the surface (300) to be printed, so that the print head (200) is always oriented substantially orthogonally to the surface (300) to be printed.
5. The method according to one of the previous claims, characterized in that the printing is performed by applying ink to the substrate, the ink being tempered to a temperature of about 43°C.
6. The method according to one of the previous claims, characterized in that the print head (200) is shaded from UV radiation by a device when it is not active.
7. A device (100) for printing a large surface (300) and a surface (300) which is located in particular on a substrate which cannot be fed to a printing device and which can be divided in one direction into printing paths corresponding to the printing width of a print head, the print head (200) being mounted on a first axis (120) so as to be movable in the vertical y-direction along a printing path, the first axis (120) being mounted on a chassis (110) which can be moved in the horizontal x-direction, and the surface (300) being printable by the sequential printing of the vertical printing paths, wherein the distance Az of the print head (200) from the surface (300) to be printed is adjustable according to a method according to one of claims 1 to 6, and the device (100) comprises a measuring device (190) for contactless measurement of the distance Az0 between the reference point of the device (100) and the surface (300) to be printed, and the device (100) further comprises a control unit for evaluation of the measured values and generation of control pulses for adjustment of the distance Az of the print head (200) from the surface (300) to be printed, wherein the chassis (110) is movable in horizontal x-direction, wherein the chassis (110) is designed to be steerable and the device (100) further comprises a control unit for calculating the steering angle of the chassis (110).
8. The device (100) according to one of claims 8 to 9, characterised in that the measuring device comprises a laser rangefinder for contactless measurement of the distance Az0 between a reference point of the device (100) and the surface (300) to be printed.
9. The device (100) according to one of claims 8 to 10, characterized in that the print head (200) has an optical sensor for detecting the starting point of the print head (200) at the beginning of each print path.
10. The device (100) according to any one of claims 8 to 11, characterized in that the device (100) comprises an extendable first axis (120) for moving the print head (200) along a print path, the first axis (120) comprising a rack.
11. The device (100) according to any one of claims 8 to 12, characterized in that the device (100) has a second axis (130) for adjusting the distance Az of the print head (200) from the surface (300) to be printed, the second axis (130) having a spindle.
12. The device (100) according to any one of claims 8 to 13, characterised in that the apparatus (100) has a temperature control device for controlling the temperature of ink to a temperature of about 43°C.
13. The device (100) according to one of claims 8 to 14, characterized in that the device (100) has a movable shading device which shades the print head (200) from UV radiation when not in use.

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