Coating application systems and methods for coating a substrate

Abstract

Coating application systems and methods for using them are provided. In an exemplary embodiment, a coating application system comprises a carrier system defined in an XYZ coordinate system, wherein the XYZ coordinate system includes an X-axis, a Y-axis, and a Z-axis, all perpendicular to each other. The X- and Y-axes define an XY plane at a zero Z-axis position. The carrier system comprises a first and a second rod, both extending in the X-direction of the XY plane. A motion rod is connected to the first and second rods and is configured to extend in the X-direction. A plurality of printheads is connected to the motion rod, the plurality of printheads comprising a first and a second printhead configured to be oriented independently of each other.

Description

PRIORITY CLAIM

[0001] This application claims priority over US Provisional Patent Application No. 63 / 510,064, filed on June 23, 2023, which is incorporated herein by reference. TECHNICAL AREA

[0002] The technical field generally concerns coating application systems and methods for coating a substrate, and in particular coating application systems that use applicators with high transfer efficiency. BACKGROUND

[0003] Inkjet printing is a non-impact printing process in which a stream of liquid ink (or other liquid coating) is applied to a substrate. These processes offer the advantage of digitally printing the substrate, which can be easily tailored to different individual requirements. The ink stream can be blasted onto the substrate using a variety of nozzle application methods, including a continuous liquid stream, drop-on-demand printing, and other techniques. The liquid coating is typically ejected by a high-efficiency applicator located in a printhead.

[0004] Conventional inkjet coatings were typically formulated to print on porous substrates such as paper and textiles, with the ink being rapidly absorbed by the substrate to allow for drying and handling shortly after printing. However, other applications are being developed, such as inkjet printing coatings for automobiles or other vehicles, as well as a wide variety of other substrates. Automotive coatings have durability requirements that are far greater than those for paper or fabric in terms of physical durability, corrosion resistance, longevity, and so on, as well as appearance requirements. Therefore, inkjet printing in automobiles typically uses different types of coatings than those used for paper, fabric, and other substrates. Other specialized coatings can be used for other applications, such as wood substrates, plastic substrates, and so on.

[0005] In the automotive industry, a vehicle body is typically coated with a series of finishes, including, for example, electrocoating, a primer, a colored basecoat that provides the color, and a clear topcoat to provide additional protection and an attractive finish. Currently, most automotive bodies are painted, with the basecoat applied in a spraying process where the paint droplets contact the substrate as an aerosol. The coating is applied using a pneumatic sprayer or rotary device that produces a wide stream of paint droplets with a broad droplet size distribution. This has the advantage of producing a uniform, high-quality coating in a relatively short time through an automated process.However, if a vehicle is to be coated with multiple colors, masking and multi-color application techniques are required. Furthermore, aerosol coating application typically results in some loss of coating product due to overspray and other factors.

[0006] Beam printing often involves applying coatings from one or more high-efficiency applicators within a printhead, with the printhead being passed sequentially over adjacent sections of the substrate during the coating process. Beam printing of automotive surfaces frequently produces visible defects at the overlap or valley between successive beam printing passes. As such, stripe overlap or stripe valley is a prevalent defect in digital printing applications. This problem is exacerbated by poor mechanical indexing precision and the flashing of a previous stripe before the continuous stripe is applied. The slight overlap or valley between different passes of a high-efficiency applicator within the printhead often produces a varying coating thickness that is visible to the human eye.

[0007] Accordingly, devices and methods for jet printing automotive components or other substrates that do not produce visible variations at the interface of different print passes are desirable. Furthermore, devices and methods for uniformly coating an automobile or other substrate using an applicator with high transfer efficiency are desirable. Other desirable features and properties will also become apparent from the following detailed description and the attached claims in conjunction with this background. BRIEF SUMMARY

[0008] Coating application systems and methods for using them are provided. In an exemplary embodiment, a coating application system comprises a carrier system defined in an XYZ coordinate system, wherein the XYZ coordinate system includes an X-axis, a Y-axis, and a Z-axis, all perpendicular to each other. The X- and Y-axes define an XY plane at a zero Z-axis position. The carrier system comprises a first and a second rod, both extending in the X-direction of the XY plane. A motion rod is connected to the first and second rods and is configured to move in the X-direction. A plurality of printheads is connected to the motion rod, the plurality of printheads comprising a first and a second printhead configured to be independently oriented.

[0009] In another embodiment, a method for coating a substrate is provided. The method comprises positioning the substrate on a substrate carrier of a coating application system, wherein the substrate has a maximum Y-substrate length and a maximum X-substrate length, as determined by an XYZ coordinate system. The substrate also has a substrate surface. A plurality of printheads is supported by a motion rod, wherein the plurality of printheads comprises a first and a second printhead, and wherein each printhead includes a high-transfer-efficiency applicator. The first and second printheads are configured to be independently oriented and are located at different Y-positions on the motion rod. The motion rod has a Y-length that is greater than the maximum Y-substrate length.The motion rod is moved across the substrate, allowing the majority of printheads to traverse the entire substrate surface. A coating is sprayed with high transfer efficiency by the applicators onto the entire substrate surface as the rod moves. The first and second printheads are independently aligned while the coating is sprayed onto the substrate surface, being positioned approximately perpendicular to the substrate surface during spraying.

[0010] Another coating application system is provided in a different embodiment. This system comprises a support system defined in an XYZ coordinate system having an X-axis, a Y-axis, and a Z-axis, all perpendicular to each other. The X- and Y-axes define an XY plane at a zero Z-axis position. The support system includes a first and a second rod, both extending in the X-direction of the XY plane. A motion rod is connected to the first and second rods and is configured to move in the X-direction. A plurality of printheads is connected to the motion rod, each plurality comprising a first and a second printhead. A substrate support is configured to carry a substrate having a maximum X-substrate length, a maximum Y-substrate length, and a substrate surface area.The motion rod has a Y-length greater than the maximum Y-substrate length, and the first and second rods have first and second rod lengths, respectively, greater than the maximum X-substrate length. A first adjustable support connects the first printhead to the motion rod, and the first adjustable support is configured to vary a first Z-printhead position. A second adjustable support connects the second printhead to the motion rod, and the second adjustable support is configured to vary a second Z-printhead position independently of the first printhead. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present disclosure is described below in conjunction with the following drawing figures, where the same reference numerals denote the same elements and where: Fig. 1 a perspective view of an embodiment of a substrate to be coated, Fig. 2 a top view of an embodiment of a substrate to be coated, Fig. 3 is a perspective view of an embodiment of a coating application system, wherein the first rod has been partially removed to provide better clarity of the embodiment of the coating application system, Fig. 4 is a side section view of an embodiment of a coating application system, Fig. 5 is a front view of an embodiment of a coating application system and Fig. Figure 6 shows a bottom view of an embodiment of a moving rod of the coating application system. DETAILED DESCRIPTION

[0012] The following detailed description is merely exemplary and is not intended to limit the application or uses of the described embodiment. Furthermore, there is no intention to be bound by any theory presented in the preceding technical field, background, summary, or the following detailed description.

[0013] A coating application system provides complete coating of a substrate surface in a single coating pass. A bridge-like carrier supports multiple printheads, each comprising one or more high-efficiency applicators. The printheads are mounted on a motion bar, which starts at one end of the substrate to be coated and moves across the substrate during the coating process. The coating application system includes enough printheads mounted on the motion bar to span the entire width of the substrate, ensuring that the entire substrate is coated in a single pass.High-efficiency applicators are preferably positioned approximately perpendicular to the substrate surface at a set printing distance for optimal performance, but the substrate surface may not be flat. For example, the substrate surface may have curves, corrugations, bumps, or other surface features for appearance, aerodynamics, ventilation, or other purposes. Therefore, at least some of the printheads align themselves during the printing process so that the high-efficiency applicators remain approximately perpendicular to the substrate surface throughout the entire printing process, even at positions where the substrate surface is not parallel to the path of the moving rod.Furthermore, the printheads can be attached to the movement shaft with an adjustable carrier such that the carrier can move the printhead up and down during the printing process, ensuring that the print distance remains within a specified range throughout the entire printing process. Since the substrate surface geometry can vary, at least some of the printheads can be oriented independently, and at least some of the printheads can adjust the print distance independently during the printing process.

[0014] With reference to Fig. 1 and Fig. 2. A substrate 10 has a substrate surface 12 that is to be coated. In some embodiments, the substrate 10 can be a component of a motor vehicle, such as a fender, hood, roof, bumper, or other component. In other embodiments, however, the substrate 10 can be other objects, such as a car, a satellite dish, or anything else. In one exemplary embodiment, the substrate 10 is a motor vehicle body part and has been coated with a primer and, optionally, an electrolytic coating. Thus, the substrate surface 12 to be coated can be the surface of the primer on the base substrate 10. The substrate 10 can be metallic in some embodiments, but in other embodiments, the substrate 10 can also be made of polymer, wood, clay, or any other solid material.In some embodiments, the substrate 10 may also be made of glass, whereby in some cases glass is not considered a "solid", the substrate 10 is essentially anything that constitutes a defined substrate surface 12 which can be coated.

[0015] The substrate 10 can have a curved substrate surface 12, as shown by the shading in Fig. Figure 1 is shown. For reference, the substrate is defined in a 3-dimensional XYZ coordinate system, where each of the X-axis 14, the Y-axis 16, and the Z-axis 18 are perpendicular to each other. The plane formed by the X- and Y-axes 14 and 16 is called the XY plane and is generally considered to be horizontal. However, it is possible for the XY plane to be vertical, horizontal, or any other angle, as long as the X-, Y-, and Z-axes 14, 16, and 18 are all perpendicular to each other and can be used to identify any point in space. As such, a point in space is defined by one X-value, one Y-value, and one Z-value, where the X-, Y-, and Z-values ​​indicate a distance along their respective axes from an origin 20, with the X-, Y-, and Z-values ​​being zero at the origin 20. The X, Y and Z coordinate system, or the Cartesian coordinate system, is well known.

[0016] Substrate 10 has a maximum X-substrate length 22, a maximum Y-substrate length 24, and a maximum Z-substrate length, where these maximum lengths are the longest dimensions of substrate 10 in each of the X, Y, and Z axes 14, 16, and 18, respectively. Each point on substrate 10 (or on the substrate surface 12) can be identified by an X, Y, and Z value representing its distance from the origin in each of the directions of the X-axis 14, the Y-axis 16, and the Z-axis 18. The X, Y, and / or Z value for any point on the substrate can be negative. For example, if substrate 10 is positioned below a reference XY plane, the Z-direction values ​​of the substrate surface would be negative or less than zero.

[0017] A partially perspective view of an embodiment of a coating application system 30 is shown in Fig. 3 illustrates, with further reference to Fig. 4. The coating application system 30 comprises a first rod 32 and a second rod 34, the first rod 32 being cut off to allow viewing of the other components. The first and second rods 32, 34 are positioned in the XY plane and extend in the X direction at a zero point along the Z-axis 18 or at a zero-Z-axis position. The first and second rods 32, 34 form a type of bridge system, with a movement rod 36 movably connected to the first and second rods 32, 34. Thus, the moving rod 36 extends along the Y-direction and moves in the X-direction along the length of the first and second rods 32, 34. The moving rod 36 can be connected to the first and second rods 32, 34 in a wide variety of ways that allow movement along the length of the first and second rods 32, 34 (i.e., movement in the X-direction).For example, the first and second rods 32, 34 can be round, and the moving rod 36 can be connected by a clamp or bearing that extends around the first and second rods 32, 34. A separate drive shaft (not illustrated) could then be used to provide the driving force to the moving rod 36. Alternatively, the first and second rods 32, 34 could include gears or teeth (not illustrated) with matching gears or teeth (not illustrated) in the moving rod 36, and a motor could engage the gears in the moving rod 36 or in the first and / or second rods 32, 34 to provide the driving force. In another embodiment, an air cushion could support the moving rod 36 on the first and second rods 32, 34 such that the moving rod 36 does not physically touch the first and second rods 32, 34, but is nevertheless connected to them by the air cushion.A wide variety of other connection systems and drive mechanisms could be used in different designs.

[0018] The moving rod 36 is illustrated as a single structure, but in some embodiments it is possible for the moving rod 36 to comprise more than one piece. In embodiments where the moving rod 36 has more than one piece, the different pieces can be connected in such a way that the pieces of the moving rod 36 move at the same speed and in the same direction.

[0019] A plurality of printheads 40 is connected to the motion rod 36, wherein the plurality of printheads 40 comprises a first printhead 42 and a second printhead 44. Each of the plurality of printheads 40 comprises one or more applicators 48 with high transfer efficiency (in Fig. (4 illustrated), wherein the coating material is ejected by the applicators 48 with high transfer efficiency. Each of the plurality of printheads 40 can comprise the same number of applicators 48 with high transfer efficiency in an exemplary embodiment, but the number of applicators 48 with high transfer efficiency per printhead can vary within a single coating application system 30.

[0020] The high-efficiency applicator 48 is used to eject the coating onto the substrate 10. The coating is ejected from one or more nozzles in a designed / controlled manner that generates a fine stream which may or may not break up into droplets. The fluid stream is directed onto the substrate 10 such that the jet or droplets arrive at specific locations to form a continuous film or pattern on the substrate 10. In an alternative embodiment, the high-efficiency applicator 48 can be configured to apply a plurality of points or droplets of the coating to the substrate, with the eye tending to combine the points to create a desired visual effect. The continuous coating described above offers more protection from the environment than the droplets, which is desirable in some embodiments.As a result, there is essentially no overspray (droplets that miss their target) and a transfer efficiency of nearly 100% (essentially all of the coating reaches the target location). In one exemplary embodiment, the transfer efficiency of the coating ultimately applied to substrate 10 is 99.9% or greater. A flat rate should be considered for starting and stopping the high-transfer-efficiency applicator 48. Devices of this type have been termed drop-on-demand, stream-on-demand, overspray-free, or ultra-high-transfer-efficiency applicators. The high-transfer-efficiency applicator 48 differs from spray atomization techniques, in which energy, such as pneumatic, hydraulic, or centrifugal energy, is supplied to produce a partially controlled, random distribution of droplet sizes, trajectories, and velocities.An additional mechanism (electrostatics and / or forming air) can optionally transfer the coating further to the substrate 10. In the case of paint spraying, there is always a certain loss of overspray and transfer efficiency.

[0021] In one embodiment, the high-efficiency applicator 48 comprises a nozzle defining a nozzle opening and having a nozzle diameter of approximately 0.00002 meters (m) to approximately 0.0004 m. In another embodiment, the high-efficiency applicator 48 can be fluidically connected to a reservoir (not illustrated) configured to contain a coating composition. For example, the high-efficiency applicator 48 can be configured to receive the coating composition from the reservoir and to eject the coating composition through the nozzle opening onto the substrate 10 to form a coating layer. The high-efficiency applicator 48 can be configured to eject the coating composition through the nozzle opening at an impact velocity of approximately 0.2 meters per second (m / s) to approximately 20 m / s.Alternatively, the applicator 48 can be designed with high transfer efficiency to eject the coating composition through the nozzle opening at an impact velocity of approximately 0.4 m / s to approximately 10 m / s or alternatively at a value outside these ranges.

[0022] The high-efficiency applicator 48 itself can be any type known in the art. For example, the high-efficiency applicator 48 is described in various embodiments as described in one or more of patent or patent publication numbers US2004 / 0217202A1, US2009 / 0304936A1, US2020 / 0070182A1, US7,824,015B2, US8,091,987B2, or US11,117,160B2, each of which is expressly incorporated herein in its entirety for use in various non-limiting embodiments. The high-efficiency applicator 48 can be mounted in a printhead.

[0023] The substrate 10 is positioned on a substrate support 46. The first and second rods 32, 34 are positioned in the XY plane, which is defined at a zero value in the Z direction. In an exemplary embodiment, the substrate support 46 and the substrate 10 on the substrate support 46 are positioned below the XY plane, so that the Z value for the entire substrate 10 and the substrate support 46 has negative values. In alternative embodiments, it is possible that the moving rod 36 is positioned in a different XY plane than the first and second rods 32, 34 and moves such that at least a portion of the substrate 10 and / or the substrate support 46 is positioned at a point above the first and second rods 32, 34, so that the Z value at a point on the substrate 10 and / or the substrate surface 12 could be positive.

[0024] The moving rod 36 has a moving rod Y-length 38 that is greater than the maximum Y-substrate length, so that the coating application system 30 can cover the entire Y-length (i.e., width) of the substrate in a single pass. The first rod 32 has a first rod length 33 (in Fig. (Figure 4 illustrates) that is greater than the maximum X-substrate length, and the second rod 34 has a second rod length 35 that is greater than the maximum X-substrate length 22. The first rod length 33 and the second rod length 35 can be the same in an exemplary embodiment, but it is also possible for these lengths to be different. Since the first and second rod lengths 33, 35 are greater than the maximum X-substrate length 22, the coating application system 30 can be configured to coat the entire X-length of the substrate 10 (i.e., the length) in a single pass. Thus, the entire substrate surface 12 can be coated in a single pass of the coating application system 30. This eliminates the overlap or valley between successive passes of a printhead, since there are no successive printhead passes.Adjacent printheads create a coating layer that may exhibit some flow at the time of application, allowing the coating from adjacent printheads to merge and combine without leaving a visible valley or overlap area on the substrate 10.

[0025] The first printhead 42 and the second printhead 44 are configured to be independently oriented, allowing them to move simultaneously in different directions relative to the motion rod 36. The first and second printheads 42, 44 (and any other printheads that can be independently oriented) can be connected to the motion rod 36 by a linkage that allows movement (relative to the motion rod 36) in the X-direction or the Y-direction, or simultaneously in both directions. For example, the linkage can be a ball-and-socket joint, allowing movement in any direction within the XY plane. Alternatively, a flexible linkage can be used that allows movement in the X- and / or Y-direction, or a set of gears can be employed.

[0026] The driving force for the movement of the first and second printheads 42, 44 can be provided in a wide variety of ways. For example, small servos or other motors can be used. Alternatively, pneumatic or hydraulic mechanisms could be used for the movement and articulation of the first and second printheads 42, 44. Other possible techniques can also be used in different embodiments. The independent alignability of the first and second printheads 42, 44 can extend to other printheads of the plurality of printheads 40. In one exemplary embodiment, all of the plurality of printheads 40 can be aligned (articulated) independently of all other printheads 40, so that each printhead can be individually aligned (articulated) independently of every other printhead.

[0027] Each of the plurality of printheads 40 can be aligned such that the high-efficiency applicator 48 is positioned approximately perpendicular to the substrate surface 12 at the point on the substrate surface 12 where coating material is applied by the high-efficiency applicator(s) 48 for each printhead. For example, the first and second printheads 42, 44 can be aligned to position the high-efficiency applicator(s) located on them within approximately ±1 degree of perpendicular to the substrate surface 12 at the point of coating application by that printhead.In an alternative embodiment, the first and second printheads 42, 44 can align themselves for coating application within approximately + / - 2 degrees perpendicular or + / - 5 degrees perpendicular or + / - 10 degrees perpendicular or within other specified ranges in different embodiments.

[0028] In some embodiments, one or more of the plurality of printheads 40 can span an area of ​​the substrate 10 that includes corrugations or other surface variations, such that the printhead 40 may be approximately perpendicular to some points of the substrate 10, but not approximately perpendicular to other areas of the substrate 10 within the area where coating is applied by the single printhead 40. As such, areas of the substrate 10 that are corrugated or otherwise have a varying surface topography may not be perpendicular to the printhead, while other areas of the substrate 10 are. Large changes in the inclination of the substrate 10 remain approximately perpendicular to the substrate 10, so that "perpendicular" to the substrate 10 means perpendicular to an average of the surface area over which each individual printhead traverses.

[0029] A side view of an embodiment of a coating application system is shown in Fig. 4 shown, with further reference to Fig. 3. The substrate 10 has a maximum Z-substrate position 58 that is smaller than the zero-Z position, the zero-Z position being located on a central axis of the first rod 32. As such, the moving rod 36 and the attached plurality of printheads 40 can be configured to move across the substrate 10 during coating application. As mentioned previously, the XY plane may not be horizontal in some embodiments, so the reference to moving “across” the substrate 10 is intended to encompass the plurality of printheads 40 all moving along one side or substrate surface 12.The first printhead 42 is connected to the motion rod 36 by a first adjustable support 50, the first adjustable support 50 being configured to vary and set a first Z-printhead position by moving the first printhead 42 up or down (relative to the motion rod 36) to adjust changes in the height (i.e., the first Z-printhead position) of the point at which the first printhead 42 applies the coating to the substrate surface 12. In one exemplary embodiment, the first printhead 42 moves up and down in a direction parallel to the Z-axis 18, but in some embodiments, the first adjustable support 50 can move the first printhead 42 in a direction that is not exactly parallel to the Z-axis 18.Similarly, the second printhead 44 is connected to the motion rod 36 via a second adjustable support 52, and the remaining plurality of printheads 40 can be connected to the motion rod 36 via a plurality of adjustable supports 54. The second Z-printhead position and optionally one or more of the remaining plurality of Z-printhead positions are adjusted such that the print distance for each printhead is within the desired specification.

[0030] The plurality of adjustable carriers 54 can be set such that a print distance, which is the distance from the high-efficiency applicator 48 to the substrate surface 12 at the coating application point, lies in a range of approximately 0.1 to approximately 3 centimeters. In alternative embodiments, however, the plurality of adjustable carriers 54 can be used to maintain the position of the plurality of printheads 40 at a print distance of approximately 0.2 to approximately 2.5 centimeters, or of approximately 0.5 to approximately 2.5 centimeters, or of 1.5 to approximately 2.5 centimeters throughout the entire coating application process in different embodiments.In embodiments where the substrate has 10 corrugations or other surface changes within the area covered by a single printhead, the printhead should be positioned such that all areas are within the aforementioned print distance range.

[0031] The amount of coating material applied per unit time can be adjusted to accommodate the orientation of any one of the plurality of printheads 40 in an exemplary embodiment. For example, if the substrate surface 12 is inclined such that the first printhead 42 is significantly angled to remain approximately perpendicular to the substrate surface 12 at the point of application, the first printhead 42 may be configured to increase the amount of coating material applied, since the inclined substrate surface 12 has a larger total surface area than a flat substrate surface 12. In alternative embodiments, however, the plurality of printheads 40 may be configured to apply the same amount of coating per unit time regardless of the angle of the substrate surface 12 and, consequently, regardless of the degree at which the printhead is oriented.

[0032] Fig. Figure 4 illustrates a Z-length detector 56 that can be used to determine the distance between the moving rod 36 (or any other suitable reference point) and the substrate surface 12 at a point under any given printhead. The Z-length detector 56 can employ light detection and distance measurement (LIDAR), acoustic detection, a probe, or other techniques to determine the distance to the substrate surface 12. The Z-length detector 56 can comprise a plurality of Z-length detectors, with each of the plurality of printheads 40 having a separate Z-length detector 56. In alternative embodiments, however, a single Z-length detector 56 can be used, or a plurality of Z-length detectors 56 can be used, with each Z-length detector 56 determining the distance to the substrate surface 12 for a section of the substrate 10. Other techniques can also be employed.

[0033] The Z-length detector 56 is connected to the coating application system 30 at a position above the substrate carrier 46. In an exemplary embodiment, the Z-length detector 56 is positioned on one or more printheads, as shown in Fig. Figure 4 illustrates this, but in alternative embodiments the Z-length detector 56 could also be positioned at a separate mounting position. For example, the Z-length detector 56 could be mounted on a separate motion rod (not illustrated), with the Z-length detector 56 moving across the substrate 10 in front of the motion rod 36, to which the plurality of printheads 40 are connected. The Z-length detector 56 can move back and forth on the separate motion rod (not illustrated), or a plurality of Z-length detectors 56 can be used, or a single position on the separate motion rod (not illustrated) may suffice to determine the distance to the substrate surface at all relevant points. Alternative embodiments for the Z-length detector 56 can also be used.

[0034] In an alternative embodiment, the coating application system 30 includes a substrate map (not illustrated) wherein the Z-position of the substrate surface 12 is stored in a memory device for positioning the plurality of printheads 40 in the Z-direction. As such, the substrate map comprises a substrate Z-position at a plurality of XY coordinate points. The substrate map (not illustrated) would be individually adapted to each substrate so that when different types of components are coated, the appropriate substrate map would be used.

[0035] With reference to Fig. 5, with further reference to Fig. 3 and Fig. Figure 4 shows the substrate carrier 46 with stands for supporting the substrate 10 in a position for coating, the stands being part of the substrate carrier 46. The movement rod 36 is positioned below the first and second rods 32, 23, and the plurality of adjustable supports 54 are shown such that the plurality of printheads 40 extend within the printing distance 60 of the substrate surface 12. The plurality of printheads 40 are shown oriented such that they remain approximately perpendicular to the substrate surface 12 at the point of coating application by each of the plurality of printheads 40.

[0036] The motion rod 36 can include one or more rows of printheads, as shown in Fig. 6 illustrates, with further reference to Fig. 3- Fig. 5. Fig. Figure 6 is a bottom view of the movement rod 36. In the Fig. In the illustrated embodiment 6, there are 3 rows of printheads, comprising a first row 62 at a first X-position 64, a second row 66 at a second X-position 68, and a third row 70 at a third X-position 72. The first, second, and third X-positions are all different and have different positions on the X-axis at any given time. The different rows 62, 66, 70 of printheads can be configured to apply different coatings in an exemplary embodiment. For example, the first row 62 at the first X-position 64 can apply a first coating to the substrate surface 12, the second row 66 at the second X-position 68 can apply a second coating to the substrate surface 12, and the third row 70 at the third X-position 72 can apply a third coating to the substrate surface 12.In some embodiments with different rows 62, 66, 70 of printheads 40, the printheads 40 in one row along the Y-axis 16 can be offset in the X-direction relative to the printheads 40 in another row along the Y-axis 16, so that printing from one of the rows (for example, the third row 70) covers gaps that were filled by a previous row (for example, the second row 66, as in ). Fig. (Illustrated in Figure 6) may be present. This type of arrangement, with the printheads 40 for rows at one Y-position offset along the X-direction relative to another row at a different Y-position, can provide a more complete and cleaner coating, as for the second and third rows 66 and 70 in Figure 6. Fig. 6 illustrates.

[0037] The first, second, and third coatings can all be different from one another, and the coating application system can include more or fewer than three rows of printheads. For example, the different coatings can be different colors, allowing a detailed color image to be printed in a single pass. The number of printhead rows could be expanded to include as many colors as needed for the color image. Alternatively, the different coatings could provide different types of coatings, such as a color layer followed by a clear coat. In yet another embodiment, the different types of coatings can provide better protection for the substrate, for example, by using different coatings with different types of binders.Other types of coating combinations are also possible.

[0038] The coating application system 30 can include one or more controller(s) 80, as shown in Fig. 4 and Fig.Figure 5 illustrates this. The controller 80 is connected to the first and second printheads 42, 44 and can be connected to the first and second adjustable carriers 50, 52. The controller is configured to control the orientation of the first and second printheads 42, 44 independently and can be configured to control the orientation of up to a majority of the printheads 40 independently. Similarly, the controller 80 (or another controller 80) can be configured to control the extension of the first and second adjustable carriers 50, 52, thereby controlling the first Z-position and the second Z-position of the printhead independently. Thus, the controller can be configured to maintain the print distance for the first and second printheads 42, 44 within the set specification, as discussed above.The controller 80 can be connected to more than just the first and second printheads 42, 44 and the first and second adjustable carriers 50, 52, so that the alignment and Z-direction settings for up to all of the majority of printheads 40 can be controlled independently by the controller.

[0039] The controller 80 can comprise a computer, a memory, a processing unit, or other devices capable of issuing commands to devices. In one exemplary embodiment, the controller 80 receives an input, such as the Z-substrate position and the substrate surface topography, and issues commands to control the position of the first and second printheads 42, 44, as discussed above. The controller 80 can comprise a physical and non-volatile memory, as well as associated components. For example, the controller 80 can include an input device, such as a keyboard and / or a mouse, and electronic communication devices, such as a modem, etc. The controller 80 can, in various embodiments, be a plurality of processing devices.In embodiments comprising a Z-length detector 56, the Z-length detector 56 transmits the Z-position of the substrate surface 12 at the desired application point, and the controller 80 uses the Z-position of the substrate surface 12 to set the Z-position of the corresponding printheads. Alternatively, the substrate map can be stored in the controller's memory and referenced to control the position and angle of the corresponding printheads.

[0040] A wide variety of coating compositions can be used in the coating application system 30. A coating composition is selected to be suitable for use in the provided process and for the substrate 10. The coating composition is particularly suitable for overspray-free applications and provides a good appearance through suitable flow and leveling, while maintaining low sag under the described conditions. The coating composition is formulated as a fluid suitable for the jet requirements of the applicators 48 with high transfer efficiency.

[0041] The coating composition contains a binder, which may be present in an amount of approximately 15 to approximately 70 wt.%, based on the total weight of the coating composition. In different embodiments, the binder is present in an amount of approximately 20 to approximately 65 wt.%, for example, approximately 25 to approximately 60 wt.%, or approximately 30 to approximately 55 wt.%. In another embodiment, the binder is present in an amount of approximately 40 to approximately 50 wt.%, for example, approximately 45 to approximately 50 wt.%, the aforementioned wt.% being based on the total weight of the coating composition. The term "binder" refers to film-forming components of the coating composition.The binder may comprise polymers, oligomers, or a combination thereof, used to form a coating composition with desired properties such as hardness, protection, adhesion, and others. In various embodiments, the binder comprises polymers capable of crosslinking during curing. Examples of binders suitable for use in the coating composition include, but are not limited to, polyurethane polymers, polyester polymers, latex polymers, acrylic and / or methacrylic polymers, epoxy polymers, melamine polymers, and a polymer possessing a crosslinkable functional group, such as an isocyanate-reactive group, wherein the polymers may be homopolymers or copolymers.Binders that crosslink upon curing typically comprise a crosslinkable component and a crosslinking component, but binders can crosslink functional groups on a single type of polymer. The binder can also cure upon exposure to ultraviolet light, electron beams, or other energy sources.

[0042] As described in more detail below, the coating composition is not particularly restricted in its form prior to application. The coating composition can be formulated and used as a one-component (i.e., "1K") composition. Alternatively, the coating composition can be a two-component (i.e., "2K") composition. It is even possible to use coating compositions with more than two components. The coating composition can be water-based or solvent-based. However, in certain embodiments, the coating composition is a solvent-based 1K composition.In an exemplary embodiment of a 1K coating composition, the composition may comprise: an acrylic binder, a polyester binder, or combinations thereof, a melamine crosslinker, an optional pigment, an organic solvent, and a polyamide wax. Control agents and / or rheology control agents, as well as other additives, such as antioxidants, surfactants, etc., may also be included. In an exemplary embodiment of a 2K coating composition, the composition comprises a hydroxyl-functional resin, an isocyanate crosslinker, an optional pigment, an organic solvent, and other additives, which may also be included, such as antioxidants, surfactants, etc. Many other types of coatings or coating compositions may also be used in various embodiments.The type of coating can be individually adapted to the desired use and effects, as experts understand.

[0043] While at least one exemplary embodiment has been presented in the preceding detailed description, it should be acknowledged that a large number of variations exist. It should also be acknowledged that the exemplary embodiment or embodiments are merely examples and are not intended to limit the scope, applicability, or configuration in any way. Rather, the preceding detailed description will provide those skilled in the art with useful guidance for implementing an exemplary embodiment. It is understood that various modifications to the function and arrangement of elements described in an exemplary embodiment may be made without deviating from the scope as set forth in the appended claims. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2004 / 0217202A1

[0022] US 2009 / 0304936A1

[0022] US 2020 / 0070182A1

[0022] US 7,824,015B2

[0022] US 8,091,987B2

[0022] US 11,117,160B2

[0022]

Claims

[1] Coating application system, comprising: a support system defined in an XYZ coordinate system, wherein the XYZ coordinate system includes an X-axis, a Y-axis and a Z-axis, all perpendicular to each other, wherein the X-axis and the Y-axis define an XY-plane, the XY-plane being at a zero Z-axis position, and wherein the support system includes a first rod and a second rod, both extending in an X-direction in the XY-plane. a movement rod connected to the first rod and the second rod, the movement rod being configured to move in the X direction, and a plurality of printheads connected to the movement rod, wherein the plurality of printheads comprises a first printhead and a second printhead, wherein the first printhead and the second printhead are configured to be aligned independently of each other. [2] Coating application system according to claim 1, further comprising: a substrate support configured to support a substrate having a maximum X-substrate length and a maximum Y-substrate length, wherein the movement rod has a Y-movement rod length greater than the maximum Y-substrate length, wherein the first rod has a first X-rod length and the second rod has a second X-rod length, wherein both the first X-rod length and the second X-rod length are greater than the maximum X-substrate length. [3] Coating application system according to claim 2, wherein: The substrate support is designed to carry the substrate in such a way that a maximum Z-substrate position is smaller than the zero Z-axis position. [4] Coating application system according to claim 2, wherein: The majority of printheads are designed to provide continuous coating of the substrate over the maximum X-substrate length and the maximum Y-substrate length in a single pass. [5] Coating application system according to claim 2, wherein: The majority of printheads comprise a first row of printheads at a first X-position and a second row of printheads at a second X-position, wherein the first X-position and the second X-position have different positions in the X-direction at any given time. [6] Coating application system according to claim 5, wherein: the first row of printheads is designed to apply an initial coating to a substrate surface, and the second row of printheads is designed to apply a second coating to the substrate surface, the second coating being different from the first coating. [7] Coating application system according to claim 2, further comprising: a Z-length detector connected to the coating application system at a position above the substrate carrier, wherein the Z-length detector is configured to determine a Z-position of a substrate surface at an XY coordinate point. [8] Coating application system according to claim 1, further comprising: a control system that is connected to the first printhead and the second printhead, wherein the control system is configured to control the orientation of the first printhead and the orientation of the second printhead such that the first printhead and the second printhead are approximately perpendicular to a substrate surface while the first printhead and the second printhead move across the substrate surface. [9] Coating application system according to claim 8, wherein: The controller includes a memory configured to store a substrate map, wherein the substrate map includes a substrate Z-position at a plurality of XY coordinate points. [10] Coating application system according to claim 1, wherein: the first printhead is connected to the motion rod by a first adjustable support, the second printhead is connected to the motion rod by a second adjustable support, the first adjustable support being configured to vary a first Z-printhead position, and the second adjustable support being configured to vary a second Z-printhead position independently of the first Z-printhead position. [11] Coating application system according to claim 10, further comprising: a controller connected to the first adjustable carrier and the second adjustable carrier, wherein the controller is configured to control an extension of the first adjustable carrier to set the first Z-printhead position, the controller is configured to control an extension of the second adjustable carrier to set the second Z-printhead position independently of the first Z-printhead position, and wherein the controller is configured to maintain a print distance of approximately 0.1 to approximately 3 centimeters for each of the first and second printheads, the print distance being individually defined by a distance between each of the plurality of printheads and a substrate surface. [12] Coating application system according to claim 1, wherein: Each of the multiple printheads is configured to be alignable independently of each other of the multiple printheads. [13] Coating application system according to claim 12, wherein: each of the plurality of printheads is connected to the motion rod by an adjustable carrier, such that the coating application system comprises a plurality of adjustable carriers, and wherein a controller is associated with each of the plurality of adjustable carriers, the controller being configured to set a Z-position of each of the plurality of printheads independently of any other of the plurality of printheads. [14] Method for coating a substrate, the method comprising the steps: Positioning the substrate on a substrate carrier of a coating application system, wherein the substrate has a maximum Y-substrate length and a maximum X-substrate length as determined by an XYZ coordinate system, and wherein the substrate further comprises a substrate surface, Carrying a plurality of printheads on a motion rod, wherein the plurality of printheads comprises a first printhead and a second printhead, each printhead comprising a high-efficiency transfer applicator, wherein the first printhead and the second printhead are configured to be independently oriented, wherein the first printhead and the second printhead are located at different Y-positions on the motion rod, and wherein the motion rod has a Y-motion rod length that is greater than the maximum Y-substrate length. Moving the motion rod across the substrate in such a way that the majority of printheads travel across the entire substrate surface, Spraying a coating from the applicators with high transfer efficiency onto the entire substrate surface while the moving rod travels over the substrate surface, and Align the first printhead and the second printhead independently while the coating is sprayed onto the substrate surface, so that the first printhead is approximately perpendicular to the substrate surface and the second printhead is approximately perpendicular to the substrate surface while the coating is sprayed onto the substrate surface. [15] Method for coating the substrate according to claim 14, wherein: The alignment of the first printhead and the second printhead further includes the use of a controller to control the alignment of the first printhead and the second printhead, wherein the controller is connected to the first printhead and the second printhead. [16] Method for coating the substrate according to claim 14, wherein: The majority of printheads are designed to spray the coating along the entire length and width of the substrate surface in a single pass. [17] Method for coating the substrate according to claim 14, wherein: Each of the multiple printheads is configured to be alignable independently of each other of the multiple printheads. [18] Method for coating the substrate according to claim 14, further comprising: Setting a first Z-position of the first printhead with a first adjustable support, wherein the first printhead is connected to the motion rod by the first adjustable support such that the first printhead is held at a printing distance of approximately 0.1 to approximately 3 centimeters from the substrate surface while the first printhead moves over the substrate surface, and Setting a second Z-printhead position of the second printhead independently of the first Z-printhead position, wherein the second Z-printhead position is set using a second adjustable support connecting the second printhead to the movement rod, and wherein the second printhead is held at a printing distance of approximately 0.1 to approximately 3 centimeters from the substrate surface while the second printhead moves across the substrate surface. [19] Method for coating the substrate according to claim 18, wherein the substrate is a motor vehicle body part. [20] Coating application system, comprising: a support system defined in an XYZ coordinate system, wherein the XYZ coordinate system includes an X-axis, a Y-axis and a Z-axis, all perpendicular to each other, wherein the X-axis and the Y-axis define an XY-plane, the XY-plane being at a zero Z-axis position, and wherein the support system includes a first rod and a second rod, both extending in an X-direction in the XY-plane. a movement rod connected to the first rod and the second rod, wherein the movement rod is configured to move in the X direction, a plurality of printheads connected to the movement rod, wherein the plurality of printheads comprises a first printhead and a second printhead, a substrate carrier configured to support a substrate having a maximum X-substrate length, a maximum Y-substrate length, and a substrate surface area, wherein the moving rod has a Y-movement rod length greater than the maximum Y-substrate length, the first rod has a first X-rod length, and the second rod has a second X-rod length, wherein both the first X-rod length and the second X-rod length are greater than the maximum X-substrate length. a first adjustable support connecting the first printhead to the motion rod, the first adjustable support being configured to vary a first Z-printhead position, and a second adjustable support connecting the second printhead to the movement rod, the second adjustable support being configured to vary a second Z-printhead position independently of the first printhead.

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