Painting system

Abstract

To provide a coating system that can improve the property of discharging air bubbles and foreign matter from inside a coating head unit.SOLUTION: A painting robot 10 comprises: a painting head unit 50 comprising a painting head 53; a robot arm R1, which moves the painting head unit 50 to a desired position; a head control unit 90, which controls operation of the painting head 53; and a control unit comprising a robot arm control unit 70, which controls operation of the robot arm R1. The robot arm control unit 70 is configured to perform: head movement control to move the painting head unit 50 to shift a posture of the painting head unit 50 from an ejection position of ejecting droplets, so as to move air bubbles B1 present in the painting head 53; and posture return control to return the posture of the painting head unit 50 to the ejection position. The head control unit 90 is configured to perform droplet ejection control to eject droplets from a nozzle 54 during or immediately after the posture return control.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a painting system including a painting robot. [Background technology]

[0002] Robotic painting using robots has become mainstream in painting lines for vehicles such as automobiles. As an example of a configuration related to this robotic painting, for example, Patent Document 1 discloses a configuration including a degassing module, a tank as an air bubble removal member, and the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7066035 Summary of the Invention [Problem to be solved by the invention]

[0004] The configuration of Patent Document 1 can remove air bubbles flowing through the flow path. It can also remove foreign matter flowing through the flow path using a filter. However, it is difficult to remove air bubbles and foreign matter that have entered the interior of an inkjet coating head unit.

[0005] If air bubbles or foreign matter remain inside the coating head unit, this can cause poor or no ejection of paint droplets from the nozzles.

[0006] The present invention has been made in light of the above circumstances, and has as its object to provide a coating system that can improve the discharge of air bubbles and foreign matter from inside a coating head unit. [Means for solving the problem]

[0007] In order to solve the above problems, according to a first aspect of the present invention, there is provided a painting system including a painting robot that paints a part of a vehicle to be painted, wherein the painting robot includes a painting head unit having a plurality of nozzles that eject droplets of paint, an internal flow path for supplying liquid paint from an external supply path to the nozzles, and a painting head that is driven to push the droplets out of the nozzles; a robot arm that has the painting head unit attached to its tip and moves the painting head unit to a desired position; a head control unit that controls the operation of the piezoelectric element of the painting head, and a robot arm control unit that controls the operation of the robot arm; the robot arm control unit controls the robot arm to perform head movement control to change the attitude of the painting head unit from an ejection position where droplets are ejected so as to move air bubbles present in the internal flow path due to the difference in specific gravity between the droplets and the bubbles, and attitude return control to return the attitude of the painting head unit to the ejection position after the head movement control; and the head control unit controls droplet ejection control to eject droplets from the nozzles of the painting head immediately after the attitude return control or between periods of the attitude return control and immediately after. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a coating system that can improve the discharge of air bubbles and foreign matter from inside the coating head unit. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing the overall configuration of a painting robot according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram showing a schematic configuration of a painting system including the painting robot shown in FIG. [Figure 3] 2 is a front view of a nozzle forming surface that ejects paint, of a paint head unit provided in the paint robot shown in FIG. 1. FIG. [Figure 4]2 is a diagram showing a schematic configuration for supplying paint to each nozzle in the painting robot shown in FIG. 1. FIG. [Figure 5] 2 is a cross-sectional view showing the configuration of the vicinity of a column-directional supply flow path, a nozzle pressurizing chamber, and a column-directional discharge flow path in the painting robot shown in FIG. 1. FIG. [Figure 6] 4 is a plan view showing the configuration of a nozzle formation surface of another paint head unit different from the paint head unit shown in FIG. 3. FIG. [Figure 7] 6 is a diagram showing an image of air bubbles and foreign matter accumulated in the nozzle pressurizing chamber in the configuration in the vicinity of the nozzle pressurizing chamber shown in FIG. 5. FIG. [Figure 8] 2A and 2B are diagrams showing an image of the operation of the paint head unit of the painting robot shown in FIG. 1 to expel air bubbles and foreign matter, where (a) shows the paint head unit inverted, (b) shows the paint head unit swung, and (c) shows the paint head unit returned to its discharge position. [Figure 9] 2A and 2B are diagrams showing an image of the operation of the paint head unit provided on the painting robot shown in FIG. 1 to expel air bubbles and foreign matter, where (a) shows the state in which paint is ejected to expel air bubbles and foreign matter, (b) shows the state in which the nozzle formation surface is wiped, and (c) shows the state in which a test pattern is printed. [Figure 10] 9(a) is a diagram showing an example of a test pattern printed in the state of FIG. 9(c), and FIG. 9(b) is an enlarged view of area A of the test pattern in FIG. 9(a). DETAILED DESCRIPTION OF THE INVENTION

[0010] A coating system 1 and a coating robot 10 according to one embodiment of the present invention will be described below with reference to the drawings. In the following description, where necessary, the X direction will be the longitudinal direction of the nozzle forming surface 52 (painting head 53), the X1 side will be the right side in Fig. 3, and the X2 side will be the left side in Fig. 3. The Y direction will be the lateral direction (width direction) of the nozzle forming surface 52 (painting head 53), the Y1 side will be the upper side in Fig. 3, and the Y2 side will be the lower side in Fig. 3.

[0011] (1. Overview of the Painting System 1 and Painting Robot 10) The painting system 1 and painting robot 10 of this embodiment "paint" objects to be painted, such as vehicles or vehicle parts (hereinafter, vehicle parts that are part of a vehicle will also be described as vehicles) located on a painting line in an automobile manufacturing factory, and are intended to form a paint film on the surface of the object to protect the surface and provide a beautiful appearance. Therefore, it is necessary to paint vehicles moving along the painting line at predetermined intervals within a certain time with the desired painting quality.

[0012] Furthermore, the painting system 1 and painting robot 10 of this embodiment are capable of not only forming the above-mentioned coating film but also forming various designs and images on objects to be painted, such as vehicles and vehicle parts. Note that the objects to be painted are not limited to vehicles and vehicle parts, and may be any parts other than automobiles (for example, exterior parts of airplanes and trains) that require painting.

[0013] (1-1. Overall Configuration of Painting System 1 and Painting Robot 10) Fig. 1 is a schematic diagram showing the overall configuration of a painting robot 10 according to one embodiment of the present invention. Fig. 2 is a diagram showing the schematic configuration of a painting system 1 including the painting robot 10 shown in Fig. 1. As shown in Fig. 2, the painting system 1 includes the painting robot 10, an image processing device 200, a camera 300, and a wiping means 400.

[0014] (1-2. About Painting Robot 10) As shown in Fig. 1, the painting robot 10 mainly comprises a robot body 20 and a painting head unit 50. The painting robot 10 shown in Fig. 1 is, as an example, a six-axis vertical articulated robot, but the painting robot 10 may be any type of robot, such as a vertical articulated type other than six axes, a horizontal articulated type, or an Cartesian robot.

[0015] (1-3. Robot body 20) 1, the robot main body 20 mainly comprises a base 21, first to sixth rotation shafts 22a to 22f, legs 23, a first rotating arm 24, a second rotating arm 25, a rotating arm 26, a wrist 27, and motors M1 to M6 (see FIG. 2) that drive these components. The portion from the legs 23 to the wrist 27 corresponds to the robot arm R1, but other portions such as the base 21 may also correspond to the robot arm R1.

[0016] Of these, the base 21 is a part that is installed on an installation site such as a floor, but the base 21 may be movable relative to the installation site. The legs 23 are parts that stand upward from the base 21 and are provided so as to be rotatable relative to the base 21 via a first rotation shaft 22a driven by a motor M1 (see FIG. 2). The legs 23 may also be configured not to rotate relative to the base 21.

[0017] A first rotating arm 24 is provided at the upper end of leg 23 so as to be rotatable via second rotating shaft 22b when driven by motor M2. Furthermore, a second rotating arm 25 is provided at the tip end of first rotating arm 24 so as to be rotatable via third rotating shaft 22c when driven by motor M3.

[0018] A rotating arm 26 is provided at the tip of the second rotating arm 25, rotatably about the center axis of the second rotating arm 25. This rotating arm 26 is rotatable via a fourth rotating shaft 22d when driven by a motor M4. A wrist unit 27 is provided at the tip of the rotating arm 26. This wrist unit 27 is capable of rotational movement around a plurality of, e.g., two, differently oriented shafts when driven by motors M5 and M6. In FIG. 1, the rotational shafts capable of this rotational movement are designated as a fifth rotating shaft 22e and a sixth rotating shaft 22f, respectively. This allows for precise control of the orientation of the painting head unit 50. The number of shafts may be any number greater than two.

[0019] Furthermore, the painting head unit 50 is attached to the wrist portion 27, but this painting head unit 50 may be provided so as to be detachable from the wrist portion 27.

[0020] (1-4. Regarding the paint / cleaning liquid supply unit 40) As shown in Fig. 2, the coating system 1 and the coating robot 10 are provided with a paint / cleaning liquid supply unit 40. The paint / cleaning liquid supply unit 40 is a part for supplying paint or cleaning liquid to the coating head unit 50. For this purpose, the paint / cleaning liquid supply unit 40 is equipped with a supply path 41 (see Fig. 4) for supplying paint from a paint reservoir (not shown) or cleaning liquid from a cleaning liquid reservoir (not shown), a pump (not shown), valves (not shown), and a return flow path 42 for recovering paint that has not been ejected or cleaning liquid that has been used for cleaning.

[0021] Here, the paint / cleaning liquid supply unit 40 is provided with a switching control valve 45. The switching control valve 45 is a control valve for switching between supplying paint from a paint reservoir (not shown) and supplying cleaning liquid from a cleaning liquid reservoir (not shown), and is operated under the control of a paint / cleaning liquid supply control unit 80 (described later). By providing such a switching control valve 45, the paint / cleaning liquid supply unit 40 can selectively supply either paint or cleaning liquid.

[0022] In addition, when a configuration is adopted in which paint is supplied from outside the painting robot 10, the painting robot 10 does not need to have a part for storing paint, and may have a part for storing paint outside the painting robot 10.

[0023] (1-5. About the painting head unit) Next, the paint head unit 50 will be described. FIG. 3 is a front view of the nozzle forming surface 52 of the paint head unit 50, from which paint is ejected. As shown in FIG. 3, the paint head unit 50 is equipped with a head cover (not shown), and various components are housed within the head cover. As shown in FIG. 3, the nozzle forming surface 52 is provided with a plurality of nozzle rows 55, in which nozzles 54 are arranged in a direction inclined with respect to the longitudinal direction of the paint head unit 50. In this embodiment, the nozzle rows 55 include a first nozzle row 55A located on one side (Y2 side) in the main scanning direction (Y direction) and a second nozzle row 55B located on the other side (Y1 side) in the main scanning direction.

[0024] When discharging paint, the drive timing of each nozzle 54 is controlled so that droplets discharged from nozzles 54 in the second nozzle row 55B land between droplets discharged from adjacent nozzles 54 in the first nozzle row 55A, thereby improving dot density during coating.

[0025] 3, a single paint head 53 is present on the nozzle forming surface 52. However, the nozzle forming surface 52 may also have a head group made up of a plurality of paint heads 53. In this case, one example is a configuration in which the plurality of paint heads 53 are aligned and arranged in a staggered pattern, but the arrangement of the paint heads 53 in the head group does not have to be staggered.

[0026] Fig. 4 is a diagram showing a schematic configuration for supplying paint to each nozzle 54. Fig. 5 is a cross-sectional view showing the configuration in the vicinity of the column-directional supply flow channel 58, the nozzle pressurizing chamber 59, and the column-directional discharge flow channel 60. As shown in Figs. 4 and 5, the coating head 53 is equipped with a large supply flow channel 57, a column-directional supply flow channel 58, the nozzle pressurizing chamber 59, a column-directional discharge flow channel 60, and a large discharge flow channel 61. The large supply flow channel 57 is a flow channel through which paint is supplied from the supply channel 41. The column-directional supply flow channel 58 is a flow channel into which the paint in the large supply flow channel 57 is diverted.

[0027] Furthermore, the nozzle pressurizing chambers 59 are connected to the column-directional supply channels 58 via the nozzle supply channels 59a. As a result, paint is supplied to the nozzle pressurizing chambers 59 from the column-directional supply channels 58. The nozzle pressurizing chambers 59 are provided in a number corresponding to the number of nozzles 54, and the paint inside can be ejected from the nozzles 54 using a piezoelectric substrate 62, which will be described later.

[0028] The nozzle pressurizing chamber 59 is also connected to the column-directional discharge flow path 60 via the nozzle discharge flow path 59b. Therefore, paint not ejected from the nozzle 54 is discharged from the nozzle pressurizing chamber 59 to the column-directional discharge flow path 60 via the nozzle discharge flow path 59b. The column-directional discharge flow path 60 is also connected to a large discharge flow path 61. The large discharge flow path 61 is a flow path where the paint discharged from each column-directional discharge flow path 60 joins together. This large discharge flow path 61 is connected to the return flow path 42.

[0029] With this configuration, paint supplied from the supply passage 41 passes through the supply-side large flow passage 57, the column-directional supply flow passage 58, the nozzle supply flow passage 59a, and the nozzle pressurizing chamber 59, before being ejected from the nozzle 54. Furthermore, paint that is not ejected from the nozzle 54 passes from the nozzle pressurizing chamber 59 through the nozzle discharge flow passage 59b, the column-directional discharge flow passage 60, and the discharge-side large flow passage 61, and is returned to the return flow passage 42.

[0030] 4, one column-directional supply flow path 58 is arranged to correspond to one column-directional discharge flow path 60. However, a plurality of (for example, two) column-directional discharge flow paths 60 may be arranged to correspond to one column-directional supply flow path 58. Also, a plurality of column-directional supply flow paths 58 may be arranged to correspond to one column-directional discharge flow path 60.

[0031] 5, a piezoelectric substrate 62 is disposed on the ceiling surface of the nozzle pressurizing chamber 59 (the surface opposite to the nozzle 54). The piezoelectric substrate 62 includes two piezoelectric ceramic layers 63a and 63b, which are piezoelectric bodies, and further includes a common electrode 64 and an individual electrode 65. The piezoelectric ceramic layers 63a and 63b are members that can expand and contract when a voltage is applied from the outside. Ferroelectric ceramic materials such as lead zirconate titanate (PZT), NaNbO3, BaTiO3, (BiNa)NbO3, and BiNaNb5O15 can be used for the piezoelectric ceramic layers 63a and 63b.

[0032] As shown in FIG. 5, the common electrode 64 is disposed between the piezoelectric ceramic layer 63a and the piezoelectric ceramic layer 63b. A surface electrode (not shown) for the common electrode is formed on the upper surface of the piezoelectric substrate 62. The common electrode 64 and the surface electrode for the common electrode are electrically connected through a through conductor (not shown) in the piezoelectric ceramic layer 63a. The individual electrodes 65 are disposed in positions facing the nozzle pressurizing chamber 59. The portion of the piezoelectric ceramic layer 63a sandwiched between the common electrode 64 and the individual electrode 65 is polarized in the thickness direction. Therefore, when a voltage is applied to the individual electrode 65, the piezoelectric ceramic layer 63a is distorted due to the piezoelectric effect. Therefore, when a predetermined drive signal is applied to the individual electrode 65, the piezoelectric ceramic layer 63b moves relatively to the nozzle pressurizing chamber 59, reducing the volume of the nozzle pressurizing chamber 59, thereby ejecting paint.

[0033] 5, the common electrode 64 is arranged on the ceiling surface of the nozzle pressurizing chamber 59, but the common electrode 64 is not limited to being arranged on the ceiling surface of the nozzle pressurizing chamber 59 as shown in Fig. 5. For example, the common electrode 64 may be arranged on a side surface of the nozzle pressurizing chamber 59 (a surface perpendicular or nearly perpendicular to the ceiling surface), or any other configuration may be adopted as long as the paint can be ejected from the nozzle 54 satisfactorily.

[0034] (1-6. Other configurations of the painting head unit) Next, another configuration of the paint head unit 50 will be described. FIG. 6 is a plan view showing the configuration of the nozzle formation surface 52 of another paint head unit 50. As shown in FIG. 6, a nozzle row 55 may be formed by arranging a plurality of nozzles 54 along the short side direction (width direction; Y direction) of the paint head 53. Note that in the configuration shown in FIG. 6, the nozzle row 55 is formed by arranging a plurality of nozzles 54 along the short side direction (width direction; main scanning direction) of the paint head 53. However, a configuration in which only one (single) nozzle 54 is arranged in the short side direction (width direction; main scanning direction) of the paint head 53 may also be used. In other words, the nozzle row 55 may be formed by a single nozzle 54.

[0035] Furthermore, when painting a vehicle using a paint head 53 such as that shown in Fig. 6, painting may be performed with the longitudinal direction of the paint head 53 slightly tilted relative to the main scanning direction of the paint head 53. For example, in the configuration of the paint head 53 shown in Fig. 3, if the nozzle rows 55 are tilted at a predetermined angle relative to the main scanning direction, then the shorter side of the paint head 53 shown in Fig. 6 can be tilted at a predetermined angle relative to the main scanning direction of the paint head 53. When tilted in this way, painting equivalent to that achieved by the paint head 53 shown in Fig. 3 can be achieved simply by adjusting the timing at which paint is ejected from each nozzle 54.

[0036] (1-7. Control configuration of painting system 1) Next, a description will be given of the control configuration for controlling the operation of the painting system 1. The control configuration described below corresponds to the control unit. As shown in FIG. 2, the painting robot 10 includes a robot arm control unit 70, a paint / cleaning liquid supply control unit 80, a head control unit 90, an imaging control unit 100, and a main control unit 110. The painting robot 10 is connected to an image processing device 200, and further includes a camera 300 and a wiping means 400, thereby constituting the painting system 1.

[0037] The robot arm control unit 70, paint / cleaning liquid supply control unit 80, head control unit 90, imaging control unit 100, main control unit 110, and image processing unit 210 (described later) are each composed of a CPU (Central Processing Unit), memory such as a storage unit (ROM (Read Only Memory), RAM (Random Access Memory), non-volatile memory, etc.), and other elements. The image processing unit 210 may use a GPU (Graphics Processing Unit) together with or instead of a CPU with excellent image processing performance.

[0038] The painting robot 10 also includes various sensors (not shown), and outputs from the sensors are input to one of the robot arm control unit 70, the paint / cleaning liquid supply control unit 80, the head control unit 90, the imaging control unit 100, and the main control unit 110. Examples of the various sensors include acceleration sensors, angular velocity sensors, position detection sensors that detect the positions of the drive units, and image sensors, but other sensors may also be used.

[0039] Of these, the robot arm control unit 70 is a part that controls the driving of the above-mentioned motors M1 to M6. The robot arm control unit 70 is provided with a memory 71, which stores programs and data created by robot teaching.

[0040] The robot arm control unit 70 controls the driving of the motors M1 to M6 based on the programs and data stored in the memory 71 and the image processing by the image processing unit 210 of the image processing device 200. This control allows the paint head unit 50 to pass through desired positions for painting at a desired speed and stop at a predetermined position. Note that the memory 71 may be provided in the paint robot 10, but it may also be external to the paint robot 10, and information may be sent and received to the memory 71 via wired or wireless communication means.

[0041] The paint / cleaning liquid supply control unit 80 controls the supply of paint or cleaning liquid to the paint head unit 50, and specifically controls the operation of the pumps and valves provided in the paint / cleaning liquid supply unit 40. The paint / cleaning liquid supply control unit 80 also controls the operation of the switching control valve 45 to selectively supply either paint or cleaning liquid from a paint reservoir (not shown) or a cleaning liquid reservoir (not shown). The paint / cleaning liquid supply control unit 80 also controls the supply pressure when paint is supplied to the paint head 53 and the recovery pressure when paint not ejected from the paint head is recovered via the return flow path.

[0042] It is preferable that the paint / cleaning liquid supply control unit 80 controls the operation of the pumps and valves so that the paint or cleaning liquid is supplied at a constant pressure to the painting head unit 50. The paint / cleaning liquid supply control unit 80 corresponds to a pressure control unit.

[0043] The head control unit 90 controls the operation of the piezoelectric substrate 62 in the paint head unit 50 based on the image processing performed by the image processing unit 210. The imaging control unit 100 controls the operation of the camera 300, which will be described later.

[0044] The main control unit 110 is a part that transmits predetermined control signals to the robot arm control unit 70, the paint and cleaning liquid supply control unit 80, the head control unit 90, and the imaging control unit 100, so that the motors M1 to M6, the paint and cleaning liquid supply unit 40, and the piezoelectric substrate 62 work together to paint the object to be painted.

[0045] The painting system 1 is also provided with an image processing device 200. The image processing device 200 includes an image processing unit 210, a determination unit 220, and a memory 230. The image processing unit 210 is a part that creates image data for each painting pass, which is a path along which the painting head 53 performs painting.

[0046] The determination unit 220 is a part that determines the test pattern captured by the camera 300, which operates under the control of the imaging control unit 100. The determination unit 220 can determine whether or not a discharge defect has occurred in the nozzle 54 and the extent of the discharge defect, based on the image data of the image of the test pattern and the image data for determination that has been stored in advance in the memory 230. The determination unit 220 corresponds to the determination means.

[0047] The memory 230 is a section that stores image data for each painting pass in correspondence with the painting order, and is also capable of storing the above-mentioned test pattern images and the judgment results from the judgment section 220.

[0048] The image processing device 200 corresponds to, for example, a computer, but the computer may be a component of the painting robot 10 or may be provided separately from the painting robot 10. When the image processing device 200 is provided separately from the painting robot 10, data is transmitted and received between the image processing device 200 and the painting robot 10 via wired or wireless communication. Even if the image processing device 200 is provided separately from the painting robot 10, it may or may not be included in the concept of the painting robot 10.

[0049] (1-8. Camera 300 and wiping means 400) Next, the camera 300 and the wiping means 400 will be described. The camera 300, which corresponds to the imaging means, can be positioned near the area where the paint head 53 applies a test pattern to the object to be painted. Therefore, the camera 300 may be fixedly disposed near the area where painting is to be performed, or may be attached to the robot arm R1 so as to move together with the paint head 53. The camera 300 may also be installed outside the paint booth where painting is performed on the vehicle.

[0050] The operation of this camera 300 is controlled by the above-mentioned imaging control unit 100. The camera 300 is also connected to the image processing device 200 so that captured image data can be transmitted via wireless or wired communication. The camera 300 is equipped with an image sensor such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor.

[0051] The wiping means 400 is provided outside the painting line where the vehicle is painted by the painting head 53 (i.e., at a location that does not interfere with the area of ​​the vehicle being painted). The wiping means 400 is a means for wiping the nozzle forming surface 52, and includes, for example, at least one of a wire and a sponge.

[0052] The wiping means 400 includes, for example, a long or flat wiping portion 410 in order to wipe the nozzle forming surface 52. Therefore, the nozzle forming surface 52 can be wiped by operating the robot arm R1 to move the nozzle forming surface 52 while the nozzle forming surface 52 is in contact with the wiping portion.

[0053] (2. About the action) The operation of the painting system 1 and painting robot 10 configured as above will be described below.

[0054] In the paint head 53 shown in Figure 5, when a predetermined amount of paint is discharged, a predetermined amount of air bubbles and foreign matter may accumulate in the flow paths of the paint head 53 (the column-directional supply flow paths 58, the nozzle supply flow paths 59a, the nozzle discharge flow paths 59b, the column-directional discharge flow paths 60, and the large discharge-side flow path 61, etc.) and in the nozzle pressurizing chamber 59. Figure 7 shows a state in which a predetermined amount of air bubbles B1 and foreign matter B2 has accumulated in the nozzle pressurizing chamber 59. As shown in Figure 7, if the accumulated state of air bubbles B1 and foreign matter B2 is left as it is, there is a risk that the discharge performance of the paint from the nozzle 54 will deteriorate.

[0055] Therefore, in this embodiment, the robot arm R1 and the coating head 53 are operated as follows to discharge the air bubbles B1 and the foreign matter B2 from the nozzle 54.

[0056] (a) Upside-down reversal of the coating head 53 from the discharge position First, as shown in Figure 8(a), in response to a command from the main control unit 110, the robot arm control unit 70 operates the robot arm R1 to turn the paint head unit 50 (paint head 53) upside down. Then, in each flow path and nozzle pressurizing chamber 59 in the paint head 53, the specific gravity between the paint and air bubbles B1 and between the paint and foreign matter B2 causes the air bubbles B1 and foreign matter B2 to move in the paint or float in the paint.

[0057] (b) Swing of the painting head 53 Next, in the upside-down state, the robot arm control unit 70 operates the robot arm R1 to swing the paint head unit 50 (paint head 53) in response to a command from the main control unit 110, as shown in Figure 8(b). This causes air bubbles B1 and foreign matter B2 to become more suspended in the paint. In particular, foreign matter B2 that has accumulated in specific locations and would not have drifted if the paint had only been turned upside down becomes more likely to drift in the paint.

[0058] This rocking may be performed after the paint head unit 50 has been turned upside down, or may be performed during the operation of turning the paint head unit 50 upside down. Rocking may also be performed both during the operation of turning the paint head unit 50 upside down and after the operation of turning the paint head unit 50 upside down. Furthermore, "rocking" includes the operation of applying a certain amplitude to the paint head 53, and therefore includes not only large rocking motions but also vibrations of the paint head 53.

[0059] Furthermore, the "oscillation" may be a reciprocating movement in a specific direction, an arc-shaped movement, a regular or irregular movement within a specific plane, or a regular or irregular movement within a specific space. In particular, when the coating head 53 is oscillated so as to move regularly or irregularly within a specific space, it is possible to increase the number of air bubbles B1 and foreign matter B2 floating in the paint.

[0060] (c) Returning to the discharge position After or in conjunction with the above-mentioned swinging of the paint head 53, the robot arm control unit 70, in response to a command from the main control unit 110, operates the robot arm R1, as shown in Figure 8(c), to return the paint head unit 50 (paint head 53) to the ejection position from which paint is ejected.

[0061] (d) Discharge of paint (air bubbles B1 and foreign matter B2) Next, in response to a command from the main control unit 110, the head control unit 90 drives the piezoelectric substrate 62 to eject paint from the paint head 53, as shown in FIG. 9(a). This ejection causes air bubbles B1 and foreign matter B2 floating in the paint to be expelled from the nozzles 54 along with the paint. It is preferable to eject paint from all of the nozzles 54 at this time in order to expel the air bubbles B1 and foreign matter B2 floating in the paint. However, it is also possible to prevent paint from being ejected from some or a single area of ​​the nozzles 54. Furthermore, the head control unit 90 may eject droplets from the nozzles 54 of the paint head 53 not only immediately after the orientation return control of the paint head unit 50 (paint head 53) but also during or immediately after the orientation return control.

[0062] By performing the above-described operations from turning the coating head 53 upside down to discharging the coating material, it is possible to discharge the air bubbles B1 and foreign matter B2 that have accumulated in the coating head 53.

[0063] (e) Wiping the nozzle forming surface 52 Next, in response to a command from the main control unit 110, the robot arm control unit 70 operates the robot arm R1 to move the coating head 53 to the outside of the coating line where coating is to be performed, as shown in Figure 9(b). The robot arm control unit 70 then presses the nozzle forming surface 52 against the wiping portion 410 of the wiping means 400 provided outside the coating line, and moves the nozzle forming surface 52 while maintaining the pressed state. This causes the wiping means 400 (wiping portion 410) to wipe the nozzle forming surface 52.

[0064] This wiping removes the paint adhering to the nozzle forming surface 52. Therefore, when droplets are ejected from the nozzles 54, the paint adhering to the nozzle forming surface 52 is prevented from being drawn in when the droplets are ejected.

[0065] Depending on the type of paint, it may be necessary to set the paint recovery pressure stronger than the paint supply pressure to the paint head 53. In such cases, there is a high possibility that air will be sucked in through the nozzles 54, making it easier for bubbles B1 to form. Therefore, with such types of paint, it is preferable to control the droplet discharge that causes paint to be discharged from the nozzles 54 before wiping the surface of the nozzle forming surface 52, and then wipe the nozzle forming surface 52 with the wiping means 400 (wiping unit 410).

[0066] (f) Printing test pattern TP After wiping the nozzle forming surface 52, the head control unit 90, in response to a command from the main control unit 110, drives the piezoelectric substrate 62 to eject paint onto the object to be painted, as shown in Fig. 9(c), and prints a predetermined test pattern TP. This test pattern TP is used to check for missing paint ejection from the nozzles 54, as is commonly done in inkjet printers. By checking this test pattern TP, it is possible to determine which nozzle 54 is experiencing a paint ejection failure.

[0067] An example of the test pattern TP is shown in Figure 10. Note that Figure 10(a) is a diagram showing an example of the test pattern TP printed in the state of Figure 9(c), and Figure 10(b) is a diagram showing an enlarged view of area A of the test pattern TP in Figure 10(a). As shown in Figures 10(a) and 10(b), the test pattern TP has a plurality of check lines MCL extending in the main scanning direction (direction S1 in Figure 10) and a plurality of check lines SCL extending in the sub-scanning direction (direction S2 in Figure 10).

[0068] The check lines SCL (SCL1 to SCL9) extending in the sub-scanning direction are check lines generated by ejecting droplets of paint from each of the multiple nozzles 54 provided on the nozzle forming surface 52 of the painting head 53 when the nozzles 54 reach a specific position in the main scanning direction.

[0069] The check lines MCL (MCL1 to MCL8) extending in the main scanning direction are generated by moving the paint head 53 in the main scanning direction while switching the nozzle 54 that ejects the paint droplets and ejecting paint droplets multiple times in succession from one of the nozzles 54, for all of the nozzles 54. The number of these check lines MCL and check lines SCL varies depending on the number of nozzles provided on the nozzle forming surface 31.

[0070] In addition, since the test pattern TP shown in FIG. 10 is intended to determine whether any of the multiple nozzles 54 is clogged or not, the check line SCL extending in the sub-scanning direction is not necessarily required, and the test pattern may consist of only the check line MCL extending in the main scanning direction.

[0071] (g) Image capture by camera 300 After printing the test pattern TP, the main control unit 110 instructs the imaging control unit 100 to operate the camera 300 to capture an image of the test pattern TP and obtain image data. The imaging data is then transmitted to the image processing device 200 via wireless or wired communication, and the image data is stored in the memory 230.

[0072] (h) Determination by the Determining Unit 220 Next, the judgment unit 220 of the image processing device 200 compares the image data stored in the memory 230 with the judgment image data, extracts unpainted check lines MCL from the test pattern TP, and judges that the nozzles 54 corresponding to the unpainted check lines MCL (corresponding to check lines MCL that are not formed due to paint gaps) are ejection defective.

[0073] If the discharge defect from the nozzle 54 satisfies a certain condition, the determination unit 220 determines that there is a discharge defect in the entire paint head 53. Here, cases where a certain condition is satisfied include when a certain number of missing check lines MCL (paint defects) in the test pattern TP has been reached, or when a certain number of missing check lines MCL (paint defects) in a certain area has been reached, but other conditions may also be used as the certain condition.

[0074] (i) Cleaning the painting head 53 If the determining unit 220 determines that there is a discharge defect in the entire paint head 53, the paint / cleaning liquid supply control unit 80 switches the switching control valve 45 from a state in which paint is supplied to a state in which cleaning liquid is discharged, in response to a command from the main control unit 110. Then, based on the command from the main control unit 110, the paint / cleaning liquid supply control unit 80 operates the pumps and valves (not shown) of the paint / cleaning liquid supply unit 40 to supply cleaning liquid to the paint head 53 and clean the paint head 53. This makes it possible to recover from the discharge defect from the nozzle 54.

[0075] However, if the above-described series of operations from turning the paint head 53 upside down to cleaning it still results in poor discharge from the nozzles 54 meeting certain conditions, the series of operations from turning the paint head 53 upside down to cleaning it may be repeated. Also, if the above-described series of operations from turning the paint head 53 upside down to cleaning it still results in poor discharge from the nozzles 54 that cannot be recovered from and affects the paint quality, the paint head 53 (paint head unit 50) may be replaced.

[0076] (3. Supplementary Note) The contents described in the above-described embodiment can be understood, for example, as follows. [1] That is, a painting system 1 including a painting robot 10 that paints a painting part of a vehicle, the painting robot 10 including a painting head unit 50 having a painting head 53 with a plurality of nozzles 54 that eject paint droplets, a robot arm R1 that has the painting head unit 50 attached to its tip and moves the painting head unit 50 to a desired position, a head control unit 90 that controls the operation of the painting head 53, and a control unit including a robot arm control unit 70 that controls the operation of the robot arm R1, the robot arm control unit 70 being the robot The head control unit 90 controls the paint head arm R1 to execute head movement control, which moves the paint head unit 50 from a discharge position where droplets are discharged so as to move air bubbles present in the paint head 53 due to the difference in specific gravity between the droplets and the air bubbles, and attitude return control, which returns the attitude of the paint head unit 50 to the discharge position after the head movement control.The head control unit 90 executes droplet discharge control, which discharges droplets from the nozzles 54 of the paint head 53 immediately after the attitude return control or during or immediately after the attitude return control.

[0077] In this way, by moving the paint head unit 50 to move the air bubbles B1 and foreign matter B2, and then ejecting droplets from all the nozzles 54 after the paint head unit 50 has returned to its original position, it is possible to expel the air bubbles B1 and foreign matter B2 that have moved inside the paint head 53 due to the change in position, along with the droplets. This reduces the amount of air bubbles B1 and foreign matter B2 remaining inside the internal flow paths of the paint head 53, making it possible to prevent poor or incapable paint droplet ejection from the nozzles 54.

[0078] [2] In addition to the above-described embodiment [1], it is preferable that the robot arm control unit 70 controls the painting head unit 50 in the discharge position to be inverted upside down when the head movement control is performed on the moving position.

[0079] In this way, by turning the paint head unit 50 upside down, the possibility of air bubbles B1 moving inside the internal flow paths of the paint head 53 increases. Also, the possibility of foreign matter B2, such as pigment in the paint that has settled inside the paint head 53, becoming floating within the paint increases. Therefore, it is possible to improve the reliability of discharging air bubbles B1 and foreign matter B2 that have moved inside the paint head 53 together with the liquid droplets.

[0080] [3] In addition to the above-described embodiments, in addition to the contents of [1] and [2], or a combination thereof, it is preferable that the robot arm control unit 70 oscillates the painting head unit 50 in the head movement control.

[0081] In this way, by rocking the paint head unit 50, the possibility of air bubbles B1 moving inside the internal flow paths of the paint head 53 increases. Also, the possibility of foreign matter B2, such as pigment in the paint that has settled inside the paint head 53, becoming floating within the paint increases. Therefore, it is possible to improve the reliability of discharging air bubbles B1 and foreign matter B2 that have moved inside the paint head 53 together with the liquid droplets.

[0082] [4] Furthermore, in the above-described embodiment, in addition to any one of the above-described items [1] to [3] or a combination thereof, it is preferable that the embodiment has a wiping means 400 for wiping the nozzle forming surface 52 of the paint head unit 50, and that after droplet ejection control, the wiping means 400 is used to wipe the nozzle forming surface 52.

[0083] In this way, by wiping the nozzle forming surface 52 with the wiping means 400 after controlling the droplet discharge, it is possible to prevent droplets adhering to the periphery of the opening of the nozzle 54 from being drawn in and discharged when actually painting a vehicle. It is also possible to prevent droplets adhering to the nozzle forming surface 52 from drying out and becoming difficult to remove from the nozzle forming surface 52.

[0084] [5] In addition to the above-mentioned embodiments described in any one of [1] to [4] above or a combination thereof, the present invention further includes a camera 300 (imaging means) capable of capturing an image of a coating area using the coating head 53, an imaging control unit 100 for controlling the operation of the camera 300 (imaging means), and a determination unit 220 (determination means) for making a predetermined determination when the image of the coating area is captured by the camera 300 (imaging means). Also included is a paint / cleaning liquid supply control unit 80 for controlling the supply of paint to the coating head unit 50 or cleaning liquid for cleaning the coating head 53, and a head control unit 90 for controlling the droplet discharge control. After execution, the operation of the paint head 53 is controlled to print a test pattern TP to check whether there are any defects in the ejection of droplets from each nozzle 54, the imaging control unit 100 controls the operation of the imaging means to capture image data for judgment by imaging after the test pattern TP is printed on the specified painting area, and the paint / cleaning liquid supply control unit 80 preferably supplies cleaning liquid to the paint head 53 and performs cleaning control of the paint head 53 when the judgment unit 220 (judgment means) judges based on the judgment image data that the ejection defects of the multiple nozzles 54 satisfy certain conditions.

[0085] In this way, after droplet discharge control, the test pattern TP is printed, and the test pattern TP is judged by the judgment unit 220 (judgment means) to confirm whether the defect in the nozzle 54 satisfies certain conditions, thereby making it possible to appropriately determine whether or not to clean the paint head 53. Then, by performing cleaning control on the paint head 53 when the discharge defect in the nozzle 54 satisfies certain conditions, it becomes possible to prevent painting defects from occurring during vehicle painting.

[0086] [6] Furthermore, in the above embodiment, in addition to any of the above items [1] to [5] or a combination thereof, it is preferable that the robot arm control unit 70 controls the painting head unit 50 to be inverted upside down, and then, in the head movement control, oscillates the painting head unit 50.

[0087] In this way, by turning the paint head unit 50 upside down and then rocking the paint head unit 50, the possibility of air bubbles B1 moving inside the internal flow paths of the paint head 53 increases. Also, the possibility of foreign matter B2, such as pigment in the paint that has settled inside the paint head 53, becoming floating within the paint increases. Therefore, it is possible to improve the reliability of discharging air bubbles B1 and foreign matter B2 that have moved inside the paint head 53 together with the liquid droplets.

[0088] [7] Furthermore, in the above embodiment, in addition to the contents described in any one of [1] to [6] above or a combination thereof, a paint / cleaning liquid supply control unit 80 (pressure control unit) is provided which controls the supply pressure when supplying paint to the paint head 53 and the recovery pressure when recovering paint not ejected from the paint head via the return flow path, and when it is determined in the control by the paint / cleaning liquid supply control unit 80 (pressure control unit) that the recovery pressure is higher than the supply pressure, it is preferable that the droplet ejection control is performed prior to the wiping operation of the wiping means 400 on the nozzle forming surface 52.

[0089] For example, depending on the type of paint, when the paint recovery pressure needs to be set higher than the paint supply pressure to the paint head 53, there is a high possibility that air will be sucked in from the nozzle 54, making it easier for bubbles B1 to be generated. However, as described above, the paint / cleaning liquid supply control unit 80 (pressure control unit) executes droplet discharge control for discharging droplets before the wiping means 400 performs the wiping operation on the nozzle forming surface 52, thereby making it possible to improve the discharge of bubbles B1 sucked in from the nozzle 54.

[0090] (4. Modifications) Although one embodiment of the present invention has been described above, the present invention can be modified in various ways other than the above embodiment. Modifications will be described below.

[0091] In the above-described embodiment, the paint head 53 employs an inkjet system that ejects droplets from the nozzles 54 using the piezoelectric substrate 62. However, the paint head is not limited to the inkjet system, and a dispenser system may also be used.

[0092] Furthermore, in the above-described embodiment, a test pattern is printed, the printed test pattern TP is captured as image data for determination using an imaging device such as the camera 300, and the determination unit 220 (determination device) determines whether or not defects in the nozzles 54 satisfy certain conditions based on the image data for determination. However, it is also possible to inspect whether or not defects exist in the nozzles 54 by directly observing the paint based on the ejected paint, rather than based on image data for determination captured from the printing of the test pattern TP. It is also possible to measure the film thickness of the test pattern TP using a device other than a camera, such as a three-dimensional displacement meter, to inspect whether or not defects exist in the nozzles 54. [Explanation of symbols]

[0093] 1...painting system, 10...painting robot, 20...robot body, 21...base, 22a...first rotating shaft, 22b...second rotating shaft, 22c...third rotating shaft, 22d...fourth rotating shaft, 22e...fifth rotating shaft, 22f...sixth rotating shaft, 23...leg, 24...first rotating arm, 25...second rotating arm, 26...rotating arm, 27...wrist section, 40...paint / cleaning liquid supply section, 41...supply path, 42...return path, 45...switching control valve, 50...painting head unit, 52...nozzle forming surface, 53...painting head, 54...nozzle, 55...nozzle row, 55A...first nozzle row, 55B...second nozzle row, 57...supply-side large flow path, 58...row-direction supply flow path, 59...nozzle pressurizing chamber, 59a...nozzle supply flow path, 59b... Nozzle discharge flow path, 60... column-direction discharge flow path, 61... discharge-side large flow path, 62... piezoelectric substrate, 63a... piezoelectric ceramic layer, 63b... piezoelectric ceramic layer, 64... common electrode, 65... individual electrode, 70... robot arm control unit, 71... memory, 80... paint / cleaning liquid supply control unit (corresponding to pressure control unit), 90... head control unit, 100... imaging control unit, 110... main control unit, 200... image processing device, 210... image processing unit, 220... determination unit (corresponding to determination means), 230... memory, 300... camera (corresponding to imaging means), 400... wiping means, 410... wiping unit, B1... air bubbles, B2... foreign matter, M1 to M6... motors, MCL, SCL... check line, R1... robot arm, TP... test pattern

Claims

1. A painting system including a painting robot that paints a painting portion of a vehicle, The painting robot a paint head unit including a paint head having a plurality of nozzles for ejecting paint droplets; a robot arm having the painting head unit attached to its tip and moving the painting head unit to a desired position; a control unit including a head control unit that controls the operation of the painting head and a robot arm control unit that controls the operation of the robot arm, The robot arm control unit controls the robot arm. a head movement control that moves the attitude of the paint head unit from a discharge position where the droplets are discharged so as to move air bubbles present in the paint head due to the difference in specific gravity between the droplets and the air bubbles; an attitude return control for returning the attitude of the painting head unit to the discharge position after the head movement control; and executes the following control. the head control unit executes droplet discharge control to discharge the droplets from the nozzles of the paint head immediately after the posture return control or during or immediately after the posture return control. A coating system characterized by:

2. 2. The coating system of claim 1, the robot arm control unit controls the painting head unit at the discharge position to be turned upside down at a movement position in the head movement control. A coating system characterized by:

3. 2. The coating system of claim 1, The robot arm control unit swings the painting head unit in the head movement control. A coating system characterized by:

4. 2. The coating system of claim 1, a wiping means for wiping the nozzle forming surface of the coating head unit; After the droplet ejection control, the wiping unit wipes the nozzle formation surface. A coating system characterized by:

5. 2. The coating system of claim 1, The coating apparatus includes an imaging means capable of imaging a coating portion by the coating head, an imaging control unit that controls the operation of the imaging means, and a determination means that makes a predetermined determination when the coating portion is imaged by the imaging means, a paint / cleaning liquid supply control unit for controlling the supply of the paint or cleaning liquid for cleaning the paint head to the paint head unit; the head control unit controls the operation of the coating head so as to print a test pattern after the droplet ejection control is performed to check whether there is any defect in the ejection of the droplets from each of the nozzles; the imaging control unit controls the operation of the imaging means to capture image data for determination by imaging after printing a test pattern on the predetermined painted area; the paint / cleaning liquid supply control unit supplies the cleaning liquid to the paint head and executes cleaning control of the paint head when the determination means determines, based on the determination image data, that the ejection defects of the plurality of nozzles satisfy a certain condition. A coating system characterized by:

6. 3. The coating system according to claim 2, the robot arm control unit swings the painting head unit in the head movement control after performing the control of turning the painting head unit upside down. A coating system characterized by:

7. 5. The coating system of claim 4, a pressure control unit that controls a supply pressure when the paint is supplied to the paint head and a recovery pressure when the paint not discharged from the paint head is recovered via a return flow path, when it is determined in the control by the pressure control unit that the recovery pressure is higher than the supply pressure, the droplet ejection control is executed before the wiping unit executes the wiping operation of the nozzle formation surface. A coating system characterized by:

Images