Head cleaning device, coating apparatus, and method for cleaning head

Abstract

To enhance cleaning performance in head cleaning.SOLUTION: A head cleaning device according to one aspect of the present invention includes: a liquid discharge head including a nozzle and a nozzle surface; a capping unit including a first channel serving as a channel for a first cleaning solution; and a control unit to control supply of the first cleaning solution. The control unit performs control so as to: supply the first cleaning solution to the first channel; stop the supply of the first cleaning solution in a state where the nozzle surface is immersed in the first cleaning solution; supply the first cleaning solution again after a predetermined immersion time has elapsed after the supply of the first cleaning solution is stopped; and stop the supply of the first cleaning solution again.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a head cleaning device, a coating device, and a head cleaning method.

Background Art

[0002] A head cleaning device and a head cleaning method for cleaning the nozzles and nozzle surface of a liquid ejection head, and a coating device having the above head cleaning device are known.

[0003] Also, a head cleaning device is disclosed that has a cleaning groove into which a nozzle surface can be inserted and supplies a cleaning liquid to the cleaning groove with the nozzle surface inserted therein (see, for example, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the device of Patent Document 1, there is room for improvement in the cleanability of the liquid ejection head.

[0005] An object of the present invention is to improve cleanability in head cleaning.

Means for Solving the Problems

[0006] A head cleaning device according to an aspect of the present invention includes a liquid ejection head including a nozzle and a nozzle surface, a capping portion including a first flow path that serves as a flow path for a first cleaning liquid, and a control portion that controls supply of the first cleaning liquid. The control portion supplies the first cleaning liquid to the first flow path, stops supply of the first cleaning liquid in a state where the nozzle surface is immersed, and after a predetermined immersion time has elapsed since supply of the first cleaning liquid was stopped, supplies the first cleaning liquid again, and then controls to stop supply of the first cleaning liquid.

Effects of the Invention

[0007] According to the present invention, cleanability in head cleaning can be improved.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] The head cleaning apparatus, coating apparatus, and head cleaning method according to the embodiments of the present invention will be described in detail with reference to the drawings. However, the following embodiments illustrate the head cleaning apparatus, coating apparatus, and head cleaning method for embodying the technical idea of the embodiments of the present invention, and are not limited thereto.

[0010] Also, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments of the present invention are not intended to limit the scope of the embodiments of the present invention only thereto, but are merely illustrative examples unless otherwise specified. Note that the sizes, positional relationships, etc. of the members shown in each drawing may be exaggerated for clarity of explanation. In the following description, the same names and reference numerals denote the same or similar members, and detailed descriptions thereof are omitted as appropriate.

[0011] [Embodiment] <Overall configuration of the coating apparatus according to an embodiment of the present invention> First, based on FIG. 1, the overall configuration of the coating apparatus according to an embodiment of the present invention will be described.

[0012] Here, as an example of the coating apparatus, a coating apparatus 100 that applies a liquid to the body of an automobile, which is an object 200, to perform body coating is exemplified. Note that the object 200 may be an aircraft fuselage, a ship hull, or other three-dimensional structures in addition to the body of an automobile.

[0013] As shown in FIG. 1, the coating apparatus 100 according to an embodiment of the present invention includes four coating robots 2.

[0014] Each coating robot 2 has a base portion 10 installed on a floor surface or the like, a first arm 11 provided on the base portion 10, a second arm 12 connected to the first arm 11, and a head unit 13 provided at the tip of the second arm 12. The first arm 11 and the second arm 12 of the coating robot 2 are robot arms that are rotatably and swingably connected via joint portions, and function as a moving mechanism that moves the head unit 13 to a desired position by rotational drive or swing drive. Note that the moving mechanism for moving the head unit 13 may be a linear actuator or the like that linearly moves the head unit 13 in one direction or two or three directions orthogonal to each other, in addition to the robot arm.

[0015] Specifically, the first arm 11 is rotatable in the direction of arrow A in FIG. 1 with respect to the base portion 10 and is swingably provided in the direction of arrow B. Further, the second arm 12 is rotatable in the direction of arrow C in FIG. 1 with respect to the tip of the first arm 11 and is swingably provided in the direction of arrow D. The head unit 13 is rotatable in the direction of arrow E in FIG. 1 with respect to the tip of the second arm 12 and is swingably attached in the direction of arrow F. The number of coating robots 2 is not limited to four, and may be one, two, three, or five or more.

[0016] The head unit 13 includes a liquid ejection head 1 and a position detection unit 3 that detects the position of the object 200. The liquid ejection head 1 includes a nozzle and a nozzle surface, and can eject liquid from the nozzle. The position detection unit 3 is attached to the tip of the second arm 12 integrally with the liquid ejection head 1. The position detection unit 3 includes, for example, a stereo camera or the like that detects three-dimensional position information of three or more feature points on the object 200. The stereo camera has a plurality of cameras. The position detection unit 3 acquires a distance image of the object 200 by a triangulation method based on the parallax between the images captured by the plurality of cameras.

[0017] In addition to the painting robot 2, the painting apparatus 100 according to the embodiment of the present invention includes a liquid supply unit 4, a maintenance and recovery unit 40, and a control unit 5.

[0018] The liquid supply unit 4 includes a liquid storage unit 6 and an air supply unit 7. The liquid storage unit 6 is, for example, a tank that stores a liquid 8 such as paint inside. The air supply unit 7 is a compressor or the like that supplies air into the liquid storage unit 6. When air is supplied from the air supply unit 7 to the liquid storage unit 6, the inside of the liquid storage unit 6 is pressurized, so that the liquid 8 in the liquid storage unit 6 is supplied to the liquid ejection head 1 and ejected as droplets from the nozzles of the liquid ejection head 1. Note that the liquid ejection head 1 can also eject the liquid in a filamentous form in addition to droplets. In FIG. 1, only the path for supplying the liquid 8 from the liquid storage unit 6 to one liquid ejection head 1 is shown, but the liquid 8 is supplied to all the liquid ejection heads 1 from the liquid storage unit 6 in the same manner. Further, a plurality of liquid storage units 6 for storing different colors or types of liquids may be prepared so that the color or type of the liquid can be switched and supplied to each liquid ejection head 1.

[0019] The maintenance and recovery unit 40 includes a capping unit 700 and the like for maintaining and recovering the functions of the liquid ejection head 1. The maintenance and recovery unit 40 is provided for each painting robot 2. When the next painting is not performed for a while after painting, or when painting is performed by switching the liquid to a different color or type, after the previous painting is completed, the maintenance and recovery operation by the maintenance and recovery unit 40 is performed. Specifically, the nozzle surface of the liquid ejection head 1 is capped, and the residual liquid adhering to the liquid ejection head 1 is washed away by the cleaning liquid. Thereby, it is possible to prevent clogging of the nozzles due to drying of the residual liquid, and to prevent adhesion of the residual liquid to the object when painting by switching the liquid.

[0020] The control unit 5 controls the operations of each painting robot 2 and the ejection operations of each liquid ejection head 1 based on the shape data of the object 200 input in advance, the image data of the painting, and the position information of the object 200 detected by the position detection unit 3. Thereby, the head unit 13 is moved along the shape of the object 200, and the liquid is applied from the liquid ejection head 1 to the surface of the object 200. Further, the control unit 5 controls the operation of the maintenance and recovery unit 40. Furthermore, the control unit 5 controls the supply of the first cleaning liquid. In FIG. 1, only the signal lines from the control unit 5 to one painting robot 2, one liquid ejection head 1, and one maintenance and recovery unit 40, and the signal line from one position detection unit 3 to the control unit 5 are shown, but the control unit 5 controls the operations of all the painting robots 2, all the liquid ejection heads 1, and all the maintenance and recovery units 40, and receives the detection signals from all the position detection units 3.

[0021] FIG. 2 is a diagram showing a more specific configuration of the liquid supply unit 4 included in the painting apparatus 100 according to the embodiment of the present invention.

[0022] As shown in FIG. 2, the liquid supply unit 4 includes a liquid storage unit 6, an air supply unit 7, and a plurality of air regulators 9. The air regulator 9 is provided in an air flow path 111 that connects the air supply unit 7 and the plurality of liquid storage units 6. The air regulator 9 adjusts the air pressure sent from the air supply unit 7 to each liquid storage unit 6. Further, the plurality of liquid storage units 6 are individually connected to each liquid discharge head 1 via an air flow path 112. Therefore, when the inside of each liquid storage unit 6 is pressurized, the liquid 8 is supplied from each liquid storage unit 6 to each liquid discharge head 1. Note that the liquid storage unit 6 may be a single liquid storage unit provided in common for all the liquid discharge heads 1, rather than being provided for each liquid discharge head 1.

[0023] <Configuration of the liquid discharge head 1> Next, with reference to FIGS. 3 and 4, the configuration of the liquid discharge head 1 included in the coating apparatus 100 according to the embodiment of the present invention will be described. FIG. 3 is a perspective view of the liquid discharge head 1 included in the coating apparatus 100 according to the embodiment of the present invention. FIG. 4 is a cross-sectional view of the liquid discharge head 1 included in the coating apparatus 100 according to the embodiment of the present invention, including a plurality of nozzles 24.

[0024] As shown in FIG. 3, the liquid discharge head 1 includes a nozzle 24 that discharges a liquid, and a nozzle surface 250 on which the nozzle holes of the nozzle 24 are arranged. Further, in the example shown in FIG. 3, the liquid discharge head 1 has a housing 20, a supply port 21 and a recovery port 22 provided in the housing 20.

[0025] As shown in FIG. 4, a plurality of ejection modules 23 are arranged side by side in one row or multiple rows within the housing 20. Each ejection module 23 includes a nozzle plate 25, a nozzle valve 26, a piezoelectric element 27, and a liquid flow path 28. The nozzle plate 25 is provided with nozzles 24 for ejecting liquid for each ejection module 23. The nozzle plate 25 includes a nozzle surface 250 on the side opposite to the side where the nozzle valve 26 is located. The nozzle 24 is configured to be openable and closable by the nozzle valve 26. The piezoelectric element 27 is a driving means that expands and contracts when a voltage is applied, and drives the nozzle valve 26 to open and close. The liquid flow paths 28 communicate with each other between the respective ejection modules 23 to form a common flow path. Further, the liquid flow path 28 also communicates with both the supply port 21 and the recovery port 22.

[0026] When liquid is supplied from the supply port 21 into the housing 20 with the valve of the recovery port 22 closed, the liquid flows into the liquid flow path 28 and is pressurized. At this time, if no voltage is applied to the piezoelectric element 27, the nozzle 24 is closed by the nozzle valve 26, so no liquid is ejected from the nozzle 24. On the other hand, when a voltage is applied to the piezoelectric element 27, the nozzle valve 26 is driven and the nozzle 24 is opened, so that liquid is ejected from the nozzle 24. Also, the liquid that was not ejected from the nozzle 24 is discharged to the outside through the recovery port 22.

[0027] <Hardware Configuration of the Coating Device 100> FIG. 5A is a block diagram showing the hardware configuration of a coating device 100 according to an embodiment of the present invention.

[0028] As shown in FIG. 5A, the coating device 100 includes, in addition to a plurality of coating robots 2, an input device 700A, a computer 300, a controller 400, a head control device 500, and a robot control device 600. Here, only two coating robots 2 are shown, and the remaining coating robots 2 are omitted.

[0029] Each painting robot 2 has an encoder sensor 16 and a robot drive unit 17. The encoder sensor 16 is an optical sensor or the like that optically detects the slits of encoders provided at the connecting portion between the base portion 10 and the first arm 11 of the painting robot 2, the connecting portion between the first arm 11 and the second arm 12, and the connecting portion between the second arm 12 and the head unit 13. Since the rotation amount and swing amount of each of the first arm 11, the second arm 12, and the head unit 13 can be grasped by the detection of the encoder sensor 16, the three-dimensional position information of the head unit 13 can be obtained. The robot drive unit 17 is a drive unit that performs the rotation operation and swing operation of the first arm 11, the second arm 12, and the head unit 13.

[0030] The input device 700A is a device into which information regarding the shape data of the object 200, the painting image data, the coordinate data, the painting mode, the painting range (painting start position, painting end position), the painting instruction, etc. is input. The input device 700A has a keyboard, a mouse, a touch panel, etc. for a user or the like to perform an input operation. Various information input in the input device 700A is sent to the computer 300.

[0031] The computer 300 has a RIP (Raster Image Processor) unit 301 that performs image processing of the image data received from the input device 700A, and a rendering unit 302 that decomposes the image data into painting data for each scan of the head unit 13. Further, the computer 300 receives the shape data of the object 200 from the input device 700A, acquires the actual position information of the object 200 detected by the position detection unit 3, and generates a painting route of the painting robot 2 based on the shape data of the object 200 and the actual position information. Further, the computer 300 calculates the incident angle α of the droplets with respect to the object 200 in the generated painting route. The incident angle α is calculated using any one of the shape data of the object 200 received from the input device 700A, the position information of the object 200 detected by the position detection unit 3, and the three-dimensional position information of the head unit 13 detected by the encoder sensor 16, or a plurality of these pieces of information.

[0032] The controller 400, the head control device 500, and the robot control device 600 function as the control unit 5 shown in FIG. 1, which controls the operations of each painting robot 2 and the discharging operations of each liquid discharge head 1. In this case, one head control device 500 and one robot control device 600 are provided, but the head control device 500 and the robot control device 600 may be provided individually for each painting robot 2.

[0033] The controller 400 receives painting data and command signals from the computer 300 and controls the overall operation of the painting apparatus 100.

[0034] The controller 400 includes a CPU (Central Processing Unit) 401, a ROM (Read Only Memory) 402, a RAM (Random Access Memory) 403, an HDD / SSD (Hard Disk Drive / Solid State Drive) 404, and an I / F 405. These are connected to be mutually communicable via a system bus S.

[0035] The CPU 401 executes control processing including various arithmetic processes. The ROM 402 stores programs used for driving the CPU 401 such as an IPL (Initial Program Loader). The RAM 403 is used as a work area for the CPU 401. The HDD / SSD 404 stores various information such as programs, captured images acquired by a stereo camera, detection information from various sensors such as an encoder sensor 16, and the like.

[0036] The I / F 405 is an interface for connecting the controller 400 to various external devices. The external devices here are the head control device 500, the robot control device 600, the first supply unit 800, the second supply unit 820, and the like.

[0037] Note that at least a part of the functions realized by the CPU 401 may be realized by an electric circuit or an electronic circuit.

[0038] The head control device 500 receives a control signal and a discharge cycle signal from the controller 400, and controls the discharge amount and discharge timing of the liquid discharge head 1 based on the received control signal and discharge cycle signal. At this time, by controlling the discharge amount and discharge timing of the liquid discharge head 1 based on the incident angle α, the amount of droplets discharged and the landing interval Px in the moving direction X are controlled to the amount of droplets and the landing interval corresponding to the incident angle α.

[0039] The robot control device 600 receives a control signal from the controller 400, and controls the drive of the robot drive unit 17 based on the received synchronization control signal. At this time, by controlling the robot drive unit 17 based on the incident angle α, the inclination β of the nozzle row of the liquid discharge head 1 is controlled, and the landing interval Py in the direction orthogonal to the movement is controlled to the landing interval corresponding to the incident angle α.

[0040] The capping unit 700 includes a first flow path that serves as a flow path for the first cleaning liquid. Further, the capping unit 700 can form a sealed space in contact with the liquid discharge head 1. More specifically, the upper surface (the surface facing the nozzle surface 250) of the capping unit 700 is open, and when cleaning, the opening contacts the nozzle surface 250 to form a sealed space including the nozzle surface 250. From another perspective, the capping unit 700 can seal the nozzle surface 250 of the liquid discharge head 1 by contacting the nozzle surface 250. The first supply unit 800 supplies the first cleaning liquid for cleaning the nozzle surface 250 shown in FIG. 4 to the capping unit 700 that forms a sealed space. The second supply unit 820 supplies the second cleaning liquid for cleaning the liquid flow path 28 of the liquid discharge head 1 to the liquid discharge head 1.

[0041] <Functional Configuration of Controller 400> FIG. 5B is a block diagram showing the functional configuration of the controller 400 provided in the coating apparatus according to the embodiment of the present invention. This will be described with appropriate reference to FIG. 5A as well.

[0042] The controller 400 includes a system control unit 411, a nozzle valve drive control unit 412, a discharge cycle signal generation unit 413, a memory control unit 414, a data storage unit 415, a robot control signal generation unit 416, a first supply control unit 417, and a second supply control unit 418.

[0043] The functions of the system control unit 411, the nozzle valve drive control unit 412, the discharge cycle signal generation unit 413, the memory control unit 414, and the robot control signal generation unit 416 are realized by a processor such as the CPU 401 executing processes defined in a program stored in a non-volatile memory such as the ROM 402. The function of the data storage unit 415 is realized by a non-volatile memory such as the HDD / SSD 404.

[0044] The system control unit 411 receives painting data and command signals from the computer 300 and controls the overall operation of the painting system 1000. Further, the system control unit 411 may include the functions of the RIP unit 301 and the rendering unit 302 included in the computer 300.

[0045] The nozzle valve drive control unit 412 generates a control signal for controlling the opening and closing drive of the nozzle valve 26 based on the painting data received from the computer 300 and the incident angle α. The discharge cycle signal generation unit 413 generates a discharge cycle signal for the liquid discharge head 1 based on the output signal from the encoder sensor 16, the painting data received from the computer 300, and the incident angle α. The memory control unit 414 controls the data storage unit 415. The data storage unit 415 stores the painting data and painting range data received from the computer 300 and the like. The robot control signal generation unit 416 generates a synchronization control signal for coordinating the drive of each painting robot 2 and the droplet discharge operation based on the painting data and the information on the painting route received from the computer 300. Further, the robot control signal generation unit 416 generates a control signal for determining the inclination β of the nozzle row of the liquid discharge head 1 based on the incident angle α calculated by the computer 300. The first supply control unit 417 controls the supply of the first cleaning liquid by the first supply unit 800. The second supply control unit 418 controls the supply of the second cleaning liquid by the second supply unit 820.

[0046] [First Embodiment] <Configuration Example of Head Cleaning Device According to First Embodiment> Next, with reference to FIGS. 6 to 9, a head cleaning device according to the first embodiment of the present invention provided in the painting device 100 will be described.

[0047] FIG. 6 is a first diagram showing the configuration of the head cleaning device 150 according to the first embodiment of the present invention. FIG. 7 is a second diagram showing the configuration of the head cleaning device 150 according to the first embodiment of the present invention. FIG. 6 shows the head cleaning device 150 in which the liquid discharge head 1 is arranged so as to be able to discharge liquid in the direction indicated by the arrow G10. FIG. 7 shows the head cleaning device 150 in which the liquid discharge head 1 is arranged so as to be able to discharge liquid in the direction indicated by the arrow G20 that is orthogonal to the direction indicated by the arrow G10 in FIG. 6.

[0048] FIG. 8 is a first diagram showing the configuration of a capping unit 700 included in the head cleaning device 150 according to the first embodiment of the present invention. FIG. 9 is a second diagram showing the configuration of the capping unit 700 included in the head cleaning device 150 according to the first embodiment of the present invention. FIG. 9 shows a cross-section of the head cleaning device 150 including a plurality of nozzles 24 included in the head cleaning device 150.

[0049] As shown in FIGS. 6 to 9, the head cleaning device 150 includes a liquid ejection head 1 including a nozzle 24 and a nozzle surface 250, a capping unit 700 including a first flow path 703 serving as a flow path for the first cleaning liquid, and a control unit 5 that controls the supply of the first cleaning liquid. The control unit 5 supplies the first cleaning liquid to the first flow path 703, stops the supply of the first cleaning liquid in a state where the nozzle surface 250 is immersed, and after a predetermined immersion time has elapsed since the supply of the first cleaning liquid was stopped, supplies the first cleaning liquid again, and then controls to stop the supply of the first cleaning liquid. In the example shown in FIGS. 6 to 9, the head cleaning device 150 includes a liquid ejection head 1 including a nozzle 24 that ejects liquid and a nozzle surface 250 where the nozzle holes 240 of the nozzle 24 are arranged. The head cleaning device 150 also includes a capping unit 700 that can form a sealed space in contact with the liquid ejection head 1, and a first supply unit 800 that supplies a first cleaning liquid for cleaning at least one of the nozzle 24 and the nozzle surface 250 to the capping unit 700 that forms the sealed space, and a control unit 5 that controls the supply of the first cleaning liquid by the first supply unit 800. The capping unit 700 includes a flow path member 702 that is arranged to face the nozzle surface 250 in the sealed space and forms the first flow path 703 for the first cleaning liquid. The control unit 5 can control to supply the first cleaning liquid to the first flow path 703 for the first cleaning liquid, stop the supply of the first cleaning liquid in a state where the nozzle surface 250 is immersed, supply the first cleaning liquid again after a predetermined immersion time has elapsed since the supply of the first cleaning liquid was stopped, and then stop the supply of the first cleaning liquid.

[0050] Here, conventionally, in a head cleaning device, various cleaning methods are used, such as a method of wiping the nozzles and nozzle surfaces with a wiping blade or an absorption member to clean the nozzles and nozzle surfaces of a liquid ejection head, or a method of spraying a cleaning liquid or air onto the nozzles and nozzle surfaces. However, in the conventional cleaning methods, when the nozzles have a complex shape or when a high-viscosity liquid is used for the coating liquid, in at least one of these cases, the coating liquid remains in the nozzles and on the nozzle surfaces, and the cleanability may be reduced. In particular, in a method of controlling the ejection of liquid by opening and closing the nozzle holes with a nozzle valve (for example, the valve jet method), since the surface layer of the nozzle has a constricted shape and a high-viscosity liquid is ejected, the cleanability tends to be low.

[0051] Also, in the first embodiment of the present invention, a first flow path 703 is formed by a flow path member 702 provided in the capping portion 700 and the nozzle surface 250, and by flowing a first cleaning liquid through the first flow path 703, each of the nozzle holes 240 and the nozzle surface 250 can be immersed in the first cleaning liquid. At this time, the coating liquid that has flowed out or eluted from inside the liquid ejection head 1 and the first cleaning liquid are in a mixed state. If it continues to be immersed in the mixed state, it becomes difficult to promote the outflow or elution of the coating liquid from inside the liquid ejection head 1, and the cleanability may not increase. For example, if the cross-sectional area of the first flow path 703 in a direction orthogonal to the direction in which the first cleaning liquid flows is narrowed in order to increase the fluid resistance of the first flow path 703, the amount of the first cleaning liquid flowing through the first flow path 703 decreases, and it becomes difficult to promote the outflow or elution of the coating liquid from inside the liquid ejection head 1.

[0052] In the first embodiment of the present invention, the head cleaning device 150 supplies the first cleaning liquid to the first flow path 703 under the control of the control unit 5, stops the supply of the first cleaning liquid in a state where the nozzle surface 250 is immersed, and after a predetermined immersion time has elapsed since the supply of the first cleaning liquid was stopped, supplies the first cleaning liquid again, and then controls to stop the supply of the first cleaning liquid. Thereby, by refreshing the first cleaning liquid in the first flow path 703, the outflow or elution of the liquid for coating from the liquid discharge head 1, which has become difficult to promote, can be promoted, and the cleaning performance by the head cleaning device 150 can be enhanced. As described above, in the first embodiment of the present invention, a head cleaning device 150 capable of improving the cleaning performance can be provided.

[0053] Further, in the head cleaning device 150, the shape of the surface of the flow path member 702 facing the nozzle surface 250 can be made substantially flat. Thereby, a narrow first flow path 703 through which the first cleaning liquid can flow can be formed between the flow path member 702 and the nozzle surface 250, and the nozzle surface 250 can be cleaned with the first cleaning liquid. In this specification, a substantially flat surface means that even if there is a deviation of 1 / 10 or less of the distance between the flow path member 702 and the nozzle surface 250 with respect to an ideal plane, it is acceptable.

[0054] In the head cleaning device 150, the liquid discharge head 1 includes a nozzle valve 26 as a valve body for opening and closing the nozzle hole 240, and a piezoelectric element 27 as a driving means for driving the nozzle valve 26 to open and close. When a sealed space is formed, the piezoelectric element 27 drives the nozzle valve 26 to open and close. Thereby, the head cleaning device 150 can control the supply of the first cleaning liquid to the first flow path 703.

[0055] In the example shown in FIGS. 6 to 9, the capping portion 700 includes a rubber member 701. The capping portion 700 can form a sealed space when the rubber member 701 contacts the nozzle surface 250 of the liquid ejection head 1. The flow path member 702 is disposed inside the rubber member 701 and faces the nozzle surface 250 in the sealed space when the capping portion 700 forms a sealed space, and as shown in FIG. 9, a first flow path 703 can be formed between the flow path member 702 and the nozzle surface 250. In FIGS. 6 to 9, for the purpose of showing that the capping portion 700 includes the rubber member 701 and the flow path member 702, the reference numerals of the capping portion 700 and the rubber member 701 are shown together, and the reference numerals of the capping portion 700 and the flow path member 702 are shown together. There may be cases where reference numerals are shown together for the same purpose hereinafter.

[0056] In the example shown in FIGS. 6 to 9, the head cleaning device 150 includes a movable plate 710 on which the capping portion 700 is placed, a plurality of springs 721 that move the movable plate 710 by applying a biasing force to the movable plate 710, and a substrate 720 that faces the movable plate 710 via the plurality of springs 721. The movable plate 710, the plurality of springs 721, and the substrate 720 constitute the maintenance and recovery portion 40 in FIG. 1. The movable plate 710 can move in the direction of arrow G30 shown in FIG. 8 and move the capping portion 700.

[0057] In the examples shown in FIGS. 6 and 7, the head cleaning device 150 includes a first cleaning liquid tank 910 that stores a first cleaning liquid, a first compressor 920 that can supply air to the capping unit 700, and a first switching valve 930 that switches the supply of the first cleaning liquid or air to the capping unit 700. The head cleaning device 150 also has a supply port 730 to which either the first cleaning liquid or air is supplied to the capping unit 700, and a discharge port 740 from which either the first cleaning liquid or air is discharged from the capping unit 700. The head cleaning device 150 further includes a first drainage tank 940 that stores the drainage of the first cleaning liquid discharged from the capping unit 700, and a second switching valve 950 that switches the flow or non-flow of the first cleaning liquid from the capping unit 700 to the first drainage tank 940. Additionally, the head cleaning device 150 includes a coating liquid tank 810 that stores the liquid for coating supplied to the liquid ejection head 1, and a liquid supply unit 4 that supplies the liquid staying in the coating liquid tank 810 to the liquid ejection head 1. In the examples shown in FIGS. 6 and 7, a configuration in which the head cleaning device 150 does not include the second supply unit 820 is illustrated, but the head cleaning device 150 may include the second supply unit 820.

[0058] An air pressurization tank, a pump, or the like can be used for the first supply unit 800. In the examples shown in FIGS. 6 and 7, the first supply unit 800 supplies the first cleaning liquid stored in the first cleaning liquid tank 910 to the first flow path 703 in the capping unit 700 through the first supply pipe 911. In the example shown in FIG. 6, the first cleaning liquid is sent through the first supply pipe 911 in the direction of arrow G11 and supplied to the first flow path 703 of the capping unit 700 through the supply port 730. In the example shown in FIG. 7, the first cleaning liquid is sent through the first supply pipe 911 in the direction of arrow G21 and supplied to the first flow path 703 of the capping unit 700 through the supply port 730.

[0059] For the first switching valve 930 and the second switching valve 950, an electromagnetic valve or the like can be used. When ending the head cleaning operation, the head cleaning device 150 stops the drive of the first supply unit 800 to stop the supply of the first cleaning liquid from the first cleaning liquid tank 910. Then, by driving the first compressor 920 to send air, the first cleaning liquid in the first flow path 703 of the capping unit 700 is discharged to the first drainage tank 940 through the first discharge pipe 941. In the example shown in FIG. 6, the first cleaning liquid discharged from the capping unit 700 through the discharge port 740 is sent in the direction of arrow G12 in the first discharge pipe 941 and discharged to the first drainage tank 940. In the example shown in FIG. 7, the first cleaning liquid discharged from the capping unit 700 through the discharge port 740 is sent in the direction of arrow G22 in the first discharge pipe 941 and discharged to the first drainage tank 940.

[0060] When the head cleaning device 150 cleans the nozzle surface 250 of the liquid ejection head 1, there are no special restrictions on the posture of the liquid ejection head 1. For example, as shown in FIG. 6, even when the liquid ejection head 1 is in a posture capable of ejecting in the direction of arrow G10, or even when it is in a posture capable of ejecting in a direction orthogonal to arrow G10, the head cleaning device 150 can clean the nozzle surface 250 of the liquid ejection head 1. In the posture shown in FIG. 7, when the supply of the first cleaning liquid to the capping unit 700 is stopped, the head difference relationship may be adjusted so that the first flow path 703 is filled with the first cleaning liquid as it is, or a configuration without a valve body may be adopted.

[0061] The component of the first cleaning liquid corresponds to the liquid for painting, and those with excellent solubility are preferred. Generally, pure water for dye-based waterborne paints and thinner for solvent paints can be mentioned. However, in practice, individual evaluation of the compatibility of the first cleaning liquid may be required for each type of paint.

[0062] <Operation Example of Head Cleaning Device 150> Next, with reference to FIGS. 10A to 10I, the operation of the head cleaning device 150 will be described. FIG. 10A is a first diagram showing a cleaning operation by the head cleaning device according to the first embodiment of the present invention. FIG. 10B is a second diagram showing a cleaning operation by the head cleaning device according to the first embodiment of the present invention. FIG. 10C is a third diagram showing a cleaning operation by the head cleaning device according to the first embodiment of the present invention. FIG. 10D is a fourth diagram showing a cleaning operation by the head cleaning device according to the first embodiment of the present invention. FIG. 10E is a fifth diagram showing a cleaning operation by the head cleaning device according to the first embodiment of the present invention. FIG. 10F is a sixth diagram showing a cleaning operation by the head cleaning device according to the first embodiment of the present invention. FIG. 10G is a seventh diagram showing a cleaning operation by the head cleaning device according to the first embodiment of the present invention. FIG. 10H is an eighth diagram showing a cleaning operation by the head cleaning device according to the first embodiment of the present invention. FIG. 10I is a ninth diagram showing a cleaning operation by the head cleaning device according to the first embodiment of the present invention. Note that FIGS. 10A to 10I are diagrams showing an enlarged view of the first flow path 703, the nozzle 24, and the nozzle valve 26 in the cross-sectional view of the liquid discharge head 1 shown in FIG. 9.

[0063] When the nozzle surface 250 of the liquid discharge head 1 is sealed by the capping portion 700, the first cleaning liquid flows through the first flow path 703, and thus, dirt such as the liquid for coating attached to the nozzle surface 250 is easy to clean. On the other hand, since it is difficult for the first cleaning liquid to flow into the nozzle 24 of the liquid discharge head 1, the cleanability inside the nozzle 24 may not be improved.

[0064] First, the head cleaning device 150 seals the liquid discharge head 1 with the capping portion 700 and fills the first flow path 703 with the first cleaning liquid. Then, a state in which the inside of the first flow path 703 is filled with the first cleaning liquid is maintained for a predetermined immersion time. As a result, the liquid for coating in the nozzle 24 flows out or elutes to the outside of the nozzle 24 due to the diffusion action of the fluid. When the liquid for coating in the nozzle 24 flows out or elutes to the outside of the nozzle 24, the head cleaning device 150 can clean the inside of the nozzle 24. Hereinafter, the cleaning operation by the head cleaning device 150 will be specifically described with reference to FIGS. 10A to 10I. Note that FIGS. 6 to 9 will also be referred to as appropriate for the description.

[0065] First, as shown in FIG. 10A, the head cleaning device 150 lowers the liquid discharge head 1 toward the flow path member 702 (in the direction of arrow G40).

[0066] Subsequently, the head cleaning device 150 brings the liquid discharge head 1 into contact with the rubber member 701 of the capping portion 700. As a result, as shown in FIG. 10B, a sealed space is formed between the liquid discharge head 1 and the capping portion 700, and a first flow path 703 is formed in the sealed space by the nozzle surface 250 and the flow path member 702.

[0067] Subsequently, the head cleaning device 150 supplies the first cleaning liquid 80 from the first cleaning liquid tank 910 to the first flow path 703 by the first supply portion 800. As shown in FIG. 10C, when the first flow path 703 is filled with the first cleaning liquid 80, in other words, when the nozzle surface 250 is immersed in the first cleaning liquid 80, the head cleaning device 150 stops the supply of the first cleaning liquid 80.

[0068] Subsequently, the head cleaning device 150 waits for a predetermined immersion time T while the supply of the first cleaning liquid is stopped. During this time, as shown in FIG. 10D, the liquid 8 for painting in the nozzle 24 flows out or elutes into the first flow path 703 due to the diffusion action of the fluid. Arrow G41 indicates the direction in which the liquid 8 for painting flows out or elutes.

[0069] Subsequently, as shown in FIG. 10E, when the liquid for coating flows out or elutes into the first flow path 703, the first cleaning liquid 80 in the first flow path 703 becomes mixed with the liquid for coating 8. Portion 81 exemplifies the portion where the first cleaning liquid 80 and the liquid for coating 8 are mixed. Even if immersed in such a mixed state, the outflow or elution of the liquid for coating 8 into the first flow path 703 is not easily promoted. This is partly because the cross-sectional area of the first flow path 703 in the direction orthogonal to the direction in which the first cleaning liquid 80 flows (the direction of arrow G42) is narrow, resulting in a small amount of the first cleaning liquid 80 flowing through the first flow path 703. Therefore, when it is necessary for the head cleaning device 150 to continue causing the liquid for coating 8 in the nozzle 24 to flow out or elute, the supply of the first cleaning liquid 80 to the first flow path 703 is started again. Thereby, the first cleaning liquid 80 is supplied from the first cleaning liquid tank 910 to the first flow path 703, and the first cleaning liquid 80 in the first flow path 703 is refreshed by flowing in the direction of arrow G42 within the first flow path 703. When the first cleaning liquid 80 in the first flow path 703 is refreshed, the head cleaning device 150 stops the supply of the first cleaning liquid 80.

[0070] Using FIG. 10F, a case where the head cleaning device 150 needs to continue causing the liquid for coating 8 in the nozzle 24 to flow out or elute will be described. After the head cleaning device 150 supplies the first cleaning liquid 80 to the first flow path 703 again and then stops the supply of the first cleaning liquid 80, it waits for a predetermined immersion time T. During this time, as shown in FIG. 10F, the liquid for coating 8 in the nozzle 24 flows out or elutes into the first flow path 703 due to the diffusion effect of the fluid. Arrow G43 indicates the direction in which the liquid for coating 8 flows out or elutes.

[0071] Subsequently, the head cleaning device 150 supplies the first cleaning liquid 80 from the first cleaning liquid tank 910 to the first flow path 703. Thereby, as shown in FIG. 10G, the first cleaning liquid 80 in the first flow path 703 is refreshed. Arrow G44 indicates the direction in which the first cleaning liquid 80 flows through the first flow path 703.

[0072] Subsequently, when the head cleaning device 150 opens the capping unit 700 after the cleaning is completed, in order to prevent the first cleaning liquid 80 remaining in the capping unit 700 from leaking, the first compressor 920 shown in FIG. 6 is driven to supply air 90 into the first flow path 703. As a result, as shown in FIG. 10H, the first cleaning liquid 80 in the first flow path 703 is discharged. Arrow G45 indicates the direction in which the first cleaning liquid 80 is discharged from the first flow path 703.

[0073] By the above procedure, as shown in FIG. 10I, the liquid 8 for painting and the first cleaning liquid 80 inside the nozzle 24 and the first flow path 703 are discharged respectively, and the state where air 90 exists is achieved. Thereby, the head cleaning device 150 can clean at least one of the nozzle 24 of the liquid discharge head 1 and the nozzle surface 250.

[0074] In addition, in the example shown in FIGS. 10A to 10I, the flow path member 702 between the liquid discharge head 1 and the capping unit 700 is a narrow flow path in which the cross-sectional area of the first flow path 703 in the direction orthogonal to the direction in which the first cleaning liquid 80 flows is narrow. Thereby, by increasing the fluid resistance to the wall surface of the first flow path 703, the cleanability of the wall surface of the first flow path 703 can be improved, and the usage amount of the first cleaning liquid 80 can be reduced.

[0075] Next, FIG. 11 is a flowchart showing the cleaning operation by the head cleaning device 150 according to the first embodiment of the present invention. The head cleaning device 150 starts the operation shown in FIG. 11, for example, when receiving an operation input for starting cleaning from the operation unit or the like of the coating device 100 shown in FIG. 1.

[0076] First, in step S11, the head cleaning device 150 moves the liquid discharge head 1 and brings the liquid discharge head 1 into contact with the capping unit 700. As a result, the nozzle surface 250 of the liquid discharge head 1 is sealed, and a sealed space is formed by the capping unit 700 (see FIGS. 10A and 10B).

[0077] Subsequently, in step S12, the head cleaning device 150 supplies the first cleaning liquid 80 to the first flow path 703 by the first supply unit 800 (see FIG. 10C). Thereafter, the head cleaning device 150 continues to supply the first cleaning liquid 80 by the first supply unit 800 until the supply of the first cleaning liquid 80 is stopped.

[0078] Subsequently, in step S13, the head cleaning device 150 determines whether the filling of the first cleaning liquid 80 into the first flow path 703 is completed (whether the nozzle surface 250 is immersed in the first cleaning liquid 80).

[0079] In step S13, if it is determined that the filling is not completed (step S13, NO), the head cleaning device 150 repeats the operation of step S13. On the other hand, if it is determined that the filling is completed (step S13, YES), the head cleaning device 150 stops the supply of the first cleaning liquid 80 to the first flow path 703 by the first supply unit 800 in step S14 (see FIG. 10D).

[0080] Subsequently, in step S15, the head cleaning device 150 measures the elapsed time since the supply of the first cleaning liquid 80 was stopped, and determines whether the elapsed time has passed a predetermined first immersion time T.

[0081] In step S15, if it is determined that the time has not passed (step S15, NO), the head cleaning device 150 repeats the operation of step S15. On the other hand, if it is determined that the time has passed (step S15, YES), the head cleaning device 150 determines whether to supply the first cleaning liquid 80 to the first flow path 703 again in order to cause the liquid for coating in the nozzle 24 to flow out or elute (see FIG. 10E).

[0082] In step S16, if it is determined that supply is required (step S16, YES), the head cleaning device 150 will perform the operations after step S12 again. On the other hand, if it is determined that supply is not required (step S16, NO), in step S17, for refreshing, the head cleaning device 150 will supply the first cleaning liquid 80 to the first flow path 703 by the first supply unit 800. After that, the head cleaning device 150 will continue to supply the first cleaning liquid 80 by the first supply unit 800 until the supply of the first cleaning liquid 80 is stopped.

[0083] Subsequently, in step S18, the head cleaning device 150 stops the supply of the first cleaning liquid 80 to the first flow path 703 by the first supply unit 800. The timing of stopping the supply of the first cleaning liquid 80 is preferably the timing when the first cleaning liquid 80 in the first flow path 703 has been refreshed. The stop of the supply of the first cleaning liquid 80 may be made according to the determination result of whether the preset refreshable time has elapsed, or may be made according to the detection result of whether a predetermined concentration has been reached by a sensor provided in the first flow path 703.

[0084] Subsequently, in step S19, the head cleaning device 150 supplies air 90 to the first flow path 703 by the first compressor 920 to discharge the first cleaning liquid 80 in the first flow path 703 (see Fig. 10H).

[0085] Subsequently, in step S20, the head cleaning device 150 opens the capping unit 700. The capping unit 700 may also be operated by the operator of the head cleaning device 150.

[0086] In the above manner, the head cleaning device 150 can clean at least one of the nozzles 24 and the nozzle surface 250 of the liquid ejection head 1.

[0087] <Modification example of cleaning operation> Hereinafter, various modified examples of the cleaning operation by the head cleaning device 150 will be described. Regarding the same names and reference numerals as those in the embodiments of the present invention already described, the same or similar members or configurations are indicated, and detailed descriptions will be omitted as appropriate. This also applies to the modified examples shown hereinafter and the embodiments of the present invention.

[0088] (First Modified Example) First, the first modified example will be described. The main difference between this modified example and the first embodiment of the present invention is that the control unit 5 causes the liquid ejection head 1 to eject liquid in a state where the nozzle surface 250 is immersed in the first cleaning liquid 80.

[0089] For example, when the nozzle holes 240 of the nozzles 24 are blocked by a thickened liquid 8 for painting or the like, the first cleaning liquid 80 may not enter the nozzles 24 as it is. In the head cleaning device 150 according to this modified example, the control unit 5 drives the nozzle valve 26 to open the nozzle holes 240, and discharges a predetermined amount of the painting liquid 8 in the nozzles 24 to the first flow path 703 between the liquid ejection head 1 and the capping unit 700. As a result, the thickened painting liquid 8 blocking the nozzle holes 240 is removed, and the first cleaning liquid 80 can enter the nozzles 24. As a result, in this modified example, the cleaning performance of the head cleaning device 150 can be improved. Hereinafter, with reference to FIGS. 12A to 12I, the cleaning operation according to the first modified example will be specifically described. Note that the figures overlapping with FIGS. 10A to 10I described above will be omitted as appropriate.

[0090] FIG. 12A is a first diagram showing a cleaning operation by the head cleaning device 150 according to the first modification. FIG. 12B is a second diagram showing a cleaning operation by the head cleaning device according to the first modification. FIG. 12C is a third diagram showing a cleaning operation by the head cleaning device according to the first modification. FIG. 12D is a fourth diagram showing a cleaning operation by the head cleaning device according to the first modification. FIG. 12E is a fifth diagram showing a cleaning operation by the head cleaning device according to the first modification. FIG. 12F is a sixth diagram showing a cleaning operation by the head cleaning device according to the first modification. FIG. 12G is a seventh diagram showing a cleaning operation by the head cleaning device according to the first modification. FIG. 12H is an eighth diagram showing a cleaning operation by the head cleaning device according to the first modification. FIG. 12I is a ninth diagram showing a cleaning operation by the head cleaning device according to the first modification. FIGS. 12A to 12I are diagrams showing an enlarged view of the first flow path 703, the nozzle 24, and the nozzle valve 26 in the cross-sectional view of the liquid ejection head 1 shown in FIG. 9. FIGS. 6 to 9 will also be referred to as appropriate for explanation.

[0091] First, the head cleaning device 150 lowers the liquid ejection head 1 toward the flow path member 702.

[0092] Subsequently, the head cleaning device 150 brings the liquid ejection head 1 into contact with the rubber member 701 of the capping portion 700. As a result, a sealed space is formed between the liquid ejection head 1 and the capping portion 700, and the first flow path 703 is formed in the sealed space by the nozzle surface 250 and the flow path member 702.

[0093] Subsequently, the head cleaning device 150 supplies the first cleaning liquid 80 from the first cleaning liquid tank 910 to the first flow path 703 by the first supply unit 800. As shown in FIG. 12A, when the first flow path 703 is filled with the first cleaning liquid 80, in other words, when the nozzle surface 250 is immersed in the first cleaning liquid 80, the head cleaning device 150 stops the supply of the first cleaning liquid 80.

[0094] When the first cleaning liquid 80 is filled in the first flow path 703, as shown in FIG. 12B, the nozzle hole 240 may be blocked by the thickened liquid for coating (referred to as the thickened liquid 8a), and the first cleaning liquid 80 may not enter the nozzle 24.

[0095] The head cleaning device 150 drives the nozzle valve 26 so that the first cleaning liquid 80 can enter the nozzle 24, and as shown in FIG. 12C, moves the nozzle valve 26 in the direction of arrow G50. Since the liquid 8 for coating is filled in the liquid flow path 28 under a pressurized state, the movement of the nozzle valve 26 causes the liquid 8 for coating to pass through the nozzle 24 and be discharged from the nozzle hole 240. Arrow G51 indicates the direction in which the liquid 8 for coating flows into the nozzle 24 in response to the movement of the nozzle valve 26. By this discharging operation, the liquid 8 in the nozzle 24 is discharged, and the thickened liquid 8a blocking the nozzle hole 240 is discharged. Thereby, the first cleaning liquid 80 can enter the nozzle 24.

[0096] Subsequently, the head cleaning device 150 waits for a predetermined immersion time T with the supply of the first cleaning liquid stopped. During this period, since the thickened liquid 8a blocking the nozzle hole 240 is removed and the nozzle hole 240 is opened, as shown in FIG. 12D, the liquid 8 for coating in the nozzle 24 flows out or elutes into the first flow path 703 due to the diffusion action of the fluid. Arrow G52 indicates the direction in which the liquid 8 for coating flows out or elutes and flows.

[0097] Subsequently, when the liquid for coating flows out or elutes into the first flow path 703, as shown in FIG. 12E, the first cleaning liquid 80 in the first flow path 703 becomes mixed with the liquid for coating 8. Portion 81 illustrates the portion where the first cleaning liquid 80 and the liquid for coating 8 are mixed. Even if the immersion continues in this mixed state, the outflow or elution of the liquid for coating 8 into the first flow path 703 is not easily promoted. This is partly because the cross-sectional area of the first flow path 703 in the direction orthogonal to the direction in which the first cleaning liquid 80 flows (the direction of arrow G53) is narrow, resulting in a small amount of the first cleaning liquid 80 flowing through the first flow path 703. Therefore, when it is necessary for the head cleaning device 150 to continue causing the liquid for coating 8 in the nozzle 24 to flow out or elute, the supply of the first cleaning liquid 80 to the first flow path 703 is started again. Thereby, the first cleaning liquid 80 is supplied from the first cleaning liquid tank 910 to the first flow path 703, and the first cleaning liquid 80 in the first flow path 703 is refreshed as it flows in the direction of arrow G53 within the first flow path 703. When the first cleaning liquid 80 in the first flow path 703 is refreshed, the head cleaning device 150 stops the supply of the first cleaning liquid 80.

[0098] Using FIG. 12F, a case where the head cleaning device 150 needs to continue causing the liquid for coating 8 in the nozzle 24 to flow out or elute will be described. After the head cleaning device 150 supplies the first cleaning liquid 80 to the first flow path 703 again and then stops the supply of the first cleaning liquid 80, it waits for a predetermined immersion time T. During this time, as shown in FIG. 12F, the liquid for coating 8 in the nozzle 24 flows out or elutes into the first flow path 703 due to the diffusion effect of the fluid. Arrow G54 indicates the direction in which the liquid for coating 8 flows out or elutes.

[0099] Subsequently, the head cleaning device 150 supplies the first cleaning liquid 80 from the first cleaning liquid tank 910 to the first flow path 703. Thereby, as shown in FIG. 12G, the first cleaning liquid 80 in the first flow path 703 is refreshed. Arrow G55 indicates the direction in which the first cleaning liquid 80 flows through the first flow path 703.

[0100] Subsequently, the head cleaning device 150 waits for a predetermined immersion time T with the supply of the first cleaning liquid 80 stopped. During this time, as shown in FIG. 12H, the liquid 8 for coating in the nozzle 24 flows out or elutes into the first flow path 703 due to the diffusion effect of the fluid. Arrow G56 indicates the direction in which the liquid 8 for coating flows out or elutes.

[0101] Subsequently, as shown in FIG. 12I, the first cleaning liquid 80 is supplied from the first cleaning liquid tank 910 to the first flow path 703, and the first cleaning liquid 80 in the first flow path 703 is refreshed. Arrow G57 indicates the direction in which the first cleaning liquid 80 flows in the first flow path 703.

[0102] As described above, the head cleaning device 150 can perform the head cleaning operation according to the second modification.

[0103] (Second Modification) Next, the first modification will be described. In this modification, the main difference from the first embodiment of the present invention is that the control unit 5 causes the liquid ejection head 1 to eject liquid in a state where the nozzle surface 250 is immersed in the first cleaning liquid 80.

[0104] For example, when the surface layer of the nozzle hole 240 is dried and an air layer 8b is formed, the first cleaning liquid 80 may not penetrate into the nozzle 24 as it is. The head cleaning device 150 according to this modification drives the nozzle valve 26 by the control unit 5 to open the nozzle hole 240, and discharges a predetermined amount of the liquid 8 for coating in the nozzle 24 into the first flow path 703 between the liquid ejection head 1 and the capping unit 700. As a result, the air layer 8b blocking the nozzle hole 240 is removed, and the first cleaning liquid 80 can enter the nozzle 24. As a result, in this modification, the cleaning performance of the head cleaning device 150 can be improved. Hereinafter, the cleaning operation according to the second modification will be specifically described with reference to FIGS. 13A to 13I. Note that the figures overlapping with FIGS. 10A to 10I described above will be omitted as appropriate.

[0105] FIG. 13A is a first diagram showing a cleaning operation by the head cleaning device 150 according to the second modification. FIG. 13B is a second diagram showing a cleaning operation by the head cleaning device according to the second modification. FIG. 13C is a third diagram showing a cleaning operation by the head cleaning device according to the second modification. FIG. 13D is a fourth diagram showing a cleaning operation by the head cleaning device according to the second modification. FIG. 13E is a fifth diagram showing a cleaning operation by the head cleaning device according to the second modification. FIG. 13F is a sixth diagram showing a cleaning operation by the head cleaning device according to the second modification. FIG. 13G is a seventh diagram showing a cleaning operation by the head cleaning device according to the second modification. FIG. 13H is an eighth diagram showing a cleaning operation by the head cleaning device according to the second modification. FIG. 13I is a ninth diagram showing a cleaning operation by the head cleaning device according to the second modification. Note that FIGS. 13A to 13I are diagrams showing an enlarged view of the first flow path 703, the nozzle 24, and the nozzle valve 26 in the cross-sectional view of the liquid ejection head 1 shown in FIG. 9. FIGS. 6 to 9 will also be referred to as appropriate for the description.

[0106] First, the head cleaning device 150 lowers the liquid ejection head 1 toward the flow path member 702.

[0107] Subsequently, the head cleaning device 150 brings the liquid ejection head 1 into contact with the rubber member 701 of the capping portion 700. As a result, a sealed space is formed between the liquid ejection head 1 and the capping portion 700, and the first flow path 703 is formed in the sealed space by the nozzle surface 250 and the flow path member 702.

[0108] Subsequently, the head cleaning device 150 supplies the first cleaning liquid 80 from the first cleaning liquid tank 910 to the first flow path 703 by the first supply unit 800. As shown in FIG. 13A, when the first flow path 703 is filled with the first cleaning liquid 80, in other words, when the nozzle surface 250 is immersed in the first cleaning liquid 80, the head cleaning device 150 stops the supply of the first cleaning liquid 80.

[0109] When the first flow path 703 is filled with the first cleaning liquid 80, as shown in FIG. 13B, the nozzle hole 240 may be blocked by the air layer 8b, and the first cleaning liquid 80 may not enter the nozzle 24.

[0110] The head cleaning device 150 drives the nozzle valve 26 so that the first cleaning liquid 80 can enter the nozzle 24, and as shown in FIG. 13C, moves the nozzle valve 26 in the direction of arrow G60. Since the liquid 8 for painting is filled in the liquid flow path 28 under pressure, the movement of the nozzle valve 26 causes the liquid 8 for painting to pass through the nozzle 24 and be discharged from the nozzle hole 240. Arrow G61 indicates the direction in which the liquid 8 for painting flows into the nozzle 24 due to the movement of the nozzle valve 26. By this discharging operation, the liquid 8 in the nozzle 24 is discharged, and the air layer 8b blocking the nozzle hole 240 is discharged. As a result, the first cleaning liquid 80 can enter the nozzle 24.

[0111] Subsequently, the head cleaning device 150 waits for a predetermined immersion time T with the supply of the first cleaning liquid stopped. During this time, since the air layer 8b blocking the nozzle hole 240 is removed and the nozzle hole 240 is opened, as shown in FIG. 13D, the liquid 8 for painting in the nozzle 24 flows out or elutes into the first flow path 703 due to the diffusion action of the fluid. Arrow G62 indicates the direction in which the liquid 8 for painting flows out or elutes and flows.

[0112] Subsequently, as shown in FIG. 13E, when the liquid for coating flows out or elutes into the first flow path 703, the first cleaning liquid 80 in the first flow path 703 becomes mixed with the liquid for coating 8. Portion 81 illustrates the portion where the first cleaning liquid 80 and the liquid for coating 8 are mixed. Even if immersed in this mixed state, the outflow or elution of the liquid for coating 8 into the first flow path 703 is not easily promoted. This is partly because the cross-sectional area of the first flow path 703 in the direction orthogonal to the direction in which the first cleaning liquid 80 flows (the direction of arrow G63) is narrow, resulting in a small amount of the first cleaning liquid 80 flowing through the first flow path 703. Therefore, when it is necessary for the head cleaning device 150 to continue causing the liquid for coating 8 in the nozzle 24 to flow out or elute, the supply of the first cleaning liquid 80 to the first flow path 703 is started again. Thereby, the first cleaning liquid 80 is supplied from the first cleaning liquid tank 910 to the first flow path 703, and the first cleaning liquid 80 in the first flow path 703 is refreshed as it flows in the direction of arrow G63 within the first flow path 703. When the first cleaning liquid 80 in the first flow path 703 has been refreshed, the head cleaning device 150 stops the supply of the first cleaning liquid 80.

[0113] Using FIG. 13F, a case where the head cleaning device 150 needs to continue causing the liquid for coating 8 in the nozzle 24 to flow out or elute will be described. After the head cleaning device 150 supplies the first cleaning liquid 80 to the first flow path 703 again and then stops the supply of the first cleaning liquid 80, it waits for a predetermined immersion time T. During this time, as shown in FIG. 13F, the liquid for coating 8 in the nozzle 24 flows out or elutes into the first flow path 703 due to the diffusion effect of the fluid. Arrow G64 indicates the direction in which the liquid for coating 8 flows out or elutes.

[0114] Subsequently, the head cleaning device 150 supplies the first cleaning liquid 80 from the first cleaning liquid tank 910 to the first flow path 703. Thereby, as shown in FIG. 13G, the first cleaning liquid 80 in the first flow path 703 is refreshed. Arrow G65 indicates the direction in which the first cleaning liquid 80 flows through the first flow path 703.

[0115] Subsequently, with the supply of the first cleaning liquid 80 stopped, the head cleaning device 150 waits for a predetermined immersion time T. During this period, as shown in FIG. 13H, the liquid 8 for coating in the nozzle 24 flows out or elutes into the first flow path 703 due to the diffusion effect of the fluid. Arrow G66 indicates the direction in which the liquid 8 for coating flows out or elutes.

[0116] Subsequently, as shown in FIG. 13I, the first cleaning liquid 80 is supplied from the first cleaning liquid tank 910 to the first flow path 703, and the first cleaning liquid 80 in the first flow path 703 is refreshed. Arrow G67 indicates the direction in which the first cleaning liquid 80 flows in the first flow path 703.

[0117] As described above, the head cleaning device 150 can perform the head cleaning operation according to the second modified example.

[0118] (Third Modified Example) Next, the third modified example will be described. The main difference between this modified example and the first embodiment of the present invention is that the head cleaning device 150 further includes a vibration applying unit that applies vibration to the first cleaning liquid 80 flowing through the first flow path 703.

[0119] The function of the vibration applying unit is realized by, for example, the control unit 5. The vibration applying unit can control the operation of the first supply unit 800 to periodically vary the flow rate of the first cleaning liquid 80 supplied to the capping unit 700, and apply the vibration accompanying the flow rate change to the first cleaning liquid 80. However, the vibration applying unit is not limited to the above. For example, the function of the vibration applying unit may be realized by a piezo actuator. The vibration applying unit can contact the piezo actuator with the first supply pipe 911 and vibrate the first supply pipe 911 by the expansion and contraction of the piezo actuator according to the applied voltage, thereby applying vibration to the first cleaning liquid 80 flowing through the first flow path 703.

[0120] FIG. 14 is a flowchart showing the cleaning operation by the head cleaning device 150 according to the third modified example. Note that the operations similar to those described in FIG. 11 will be omitted as appropriate, and the differences from FIG. 11 will be mainly described.

[0121] In step S24, after the supply of the first cleaning liquid 80 is stopped, the head cleaning device 150, in step S25, applies vibration to the first cleaning liquid 80 flowing through the first flow path 703 by the vibration applying unit. The head cleaning device 150 then continues to apply vibration to the first cleaning liquid 80 by the vibration applying unit until the application of vibration is stopped. By applying vibration to the first cleaning liquid 80, it is possible to diffuse the liquid 8 for coating that has flowed out or eluted near the nozzle holes 240 and prevent a decrease in solubility. As a result, in this modified example, the cleaning performance by the head cleaning device 150 can be improved. Also, in this modified example, the apparent holding time of the first cleaning liquid 80 may be shortened. Note that the vibration applying unit may continue to apply vibration for a predetermined time, or may repeatedly apply vibration and stop the application of vibration periodically or aperiodically.

[0122] Also, in step S27, the head cleaning device 150 determines whether to supply the first cleaning liquid 80 to the first flow path 703 again in order to continue to cause the liquid for coating in the nozzle 24 to flow out or elute.

[0123] If it is determined in step S27 that supply is to be made (step S27, YES), the head cleaning device 150 stops the application of vibration by the vibration applying unit in step S28. Then, the operations after step S22 are performed again. On the other hand, if it is determined that supply is not to be made (step S27, NO), the head cleaning device 150 stops the application of vibration by the vibration applying unit in step S29 in order to end the head cleaning operation. Then, in step S30, the first cleaning liquid 80 is supplied to the first flow path 703 for refreshing.

[0124] The head cleaning device 150 can perform the cleaning operation according to the third modified example according to the procedure illustrated in FIG. 14.

[0125] (Fourth Modified Example) Next, a fourth modification example will be described. In this modification example, in order to remove the thickened liquid 8a and the air layer 8b described above, the nozzle valve 26 is opened to discharge the liquid to the liquid discharge head 1. After the first filling of the first cleaning liquid 80, the nozzle valve 26 is opened. After the second filling of the first cleaning liquid 80, the main difference from the second modification example is that the nozzle valve 26 is closed.

[0126] FIG. 15 is a flowchart showing the cleaning operation by the head cleaning device 150 according to the fourth modification example. Note that the operations similar to those described in FIG. 11 will be omitted as appropriate, and the differences from FIG. 11 will be mainly described.

[0127] In step S45, the head cleaning device 150 determines whether to open or close the nozzle valve 26.

[0128] In step S45, if it is determined not to open or close (step S45, NO), the head cleaning device 150 repeats the operation of step S45. On the other hand, if it is determined to open or close (step S45, YES), the head cleaning device 150 executes the opening and closing operation of the nozzle valve 26 in step S46. For example, the head cleaning device 150 opens the nozzle valve 26.

[0129] In step S48, the head cleaning device 150 determines whether to supply the first cleaning liquid 80 to the first flow path 703 again in order to cause the liquid for coating in the nozzle 24 to flow out or elute.

[0130] In step S48, if it is determined to supply (step S48, YES), the head cleaning device 150 closes the nozzle valve 26 in step S49. Then, the operations after step S42 are repeated. On the other hand, if it is determined not to supply (step S48, NO), the head cleaning device 150 closes the nozzle valve 26 in step S50 to end the head cleaning operation. Then, in step S51, the first cleaning liquid 80 is supplied to the first flow path 703 for refreshing.

[0131] The head cleaning device 150 can perform the cleaning operation according to the fourth modification example by the procedure illustrated in FIG. 15.

[0132] [Second Embodiment] <Configuration Example of Head Cleaning Device According to Second Embodiment> Next, with reference to FIG. 16, the head cleaning device according to the second embodiment of the present invention provided in the coating device 100 will be described. FIG. 16 is a diagram showing the configuration of the head cleaning device 150a according to the second embodiment of the present invention.

[0133] In the second embodiment of the present invention, the head cleaning device 150a has a second supply unit 820 that supplies a second cleaning liquid for cleaning the liquid flow path 28 of the liquid ejection head 1 to the liquid ejection head 1. Here, the liquid flow path 28 is an example of the second flow path. After cleaning the liquid ejection head 1 by supplying the second cleaning liquid to the liquid ejection head 1 by the second supply unit 820, the control unit 5 supplies the first cleaning liquid 80 to the first flow path 703 of the capping unit 700 by the first supply unit 800. The above points are mainly different from the first embodiment.

[0134] In the second embodiment of the present invention, by supplying the second cleaning liquid to the liquid flow path 28 of the liquid ejection head 1 by the second supply unit 820, in addition to at least one of the nozzles 24 and the nozzle surface 250 of the liquid ejection head 1, the liquid flow path 28 of the liquid ejection head 1 can be further cleaned.

[0135] In the example shown in FIG. 16, the coating apparatus 100 has a second cleaning liquid tank 830 that stores a second cleaning liquid. The head cleaning device 150a includes a second compressor 840 capable of supplying air to the liquid ejection head 1, and a third switching valve 850 that switches the supply of the second cleaning liquid or air to the capping unit 700. The head cleaning device 150a also has a fourth switching valve 860 that switches the supply of the liquid for coating or the second cleaning liquid to the liquid ejection head 1. Further, the head cleaning device 150a includes a second drainage tank 870 that stores the drained second cleaning liquid discharged from the capping unit 700, and a fifth switching valve 880 that switches the flow or non-flow from the capping unit 700 to the second drainage tank 870. The above points are mainly different from FIG. 6.

[0136] In the second embodiment of the present invention, when coating an object, the head cleaning device 150a switches the fourth switching valve 860. As a result, the liquid 8 for coating can be supplied from the coating liquid tank 810 to the liquid ejection head 1, and the supply of the second cleaning liquid through the second supply pipe 831 from the second cleaning liquid tank 830 to the liquid ejection head 1 is blocked. The liquid supplied from the coating liquid tank 810 is supplied to the supply port 21 (see FIG. 4). The second discharge pipe 871 leading to the second drainage tank 870 in FIG. 16 is connected to the recovery port 22 (see FIG. 4) of the liquid ejection head 1.

[0137] On the one hand, when cleaning the liquid flow path 28 in the liquid ejection head 1, the head cleaning device 150a switches the fourth switching valve 860. Thereby, the supply of liquid from the coating liquid tank 810 to the liquid ejection head 1 is stopped, and the second cleaning liquid can be supplied from the second cleaning liquid tank 830 to the liquid ejection head 1 through the second supply pipe 831. In the head cleaning device 150a, the coating liquid tanks 810 for supplying the liquid ejection head 1 may be provided for each of a plurality of colors, and the fourth switching valves 860 provided for each of the plurality of colors may be switched. By doing so, the coating device 100 can change the color to be coated. When the color to be coated is changed, the head cleaning device 150a stops the supply of liquid from the coating liquid tank 810 to the liquid ejection head 1 and enables the supply of the second cleaning liquid from the second cleaning liquid tank 830 to the liquid ejection head 1. After the head cleaning device 150a cleans the liquid ejection head 1 with the second cleaning liquid, it can supply the liquid for coating from the coating liquid tank of another color to the liquid ejection head 1.

[0138] In the example shown in FIG. 16, the second cleaning liquid tank 830 for supplying the second cleaning liquid to the liquid ejection head 1 and the first cleaning liquid tank 910 for supplying the first cleaning liquid to the capping unit 700 are provided separately. However, the present invention is not limited to this configuration, and the first cleaning liquid and the second cleaning liquid may be the same, and the cleaning liquid tanks may be shared. The cleaning liquid may be branched from a common cleaning liquid tank to the liquid ejection head 1 and the capping unit 700 to enable the supply of the cleaning liquid.

[0139] <Operation example of the head cleaning device 150a> FIG. 17A is a first diagram showing a cleaning operation by the head cleaning device according to the second embodiment of the present invention. FIG. 17B is a second diagram showing a cleaning operation by the head cleaning device according to the second embodiment of the present invention. FIG. 17C is a third diagram showing a cleaning operation by the head cleaning device according to the second embodiment of the present invention. FIG. 17D is a fourth diagram showing a cleaning operation by the head cleaning device according to the second embodiment of the present invention. FIG. 17E is a fifth diagram showing a cleaning operation by the head cleaning device according to the second embodiment of the present invention. FIG. 17F is a sixth diagram showing a cleaning operation by the head cleaning device according to the second embodiment of the present invention. FIG. 17G is a seventh diagram showing a cleaning operation by the head cleaning device according to the second embodiment of the present invention. FIG. 17H is an eighth diagram showing a cleaning operation by the head cleaning device according to the second embodiment of the present invention. FIG. 17I is a ninth diagram showing a cleaning operation by the head cleaning device according to the second embodiment of the present invention. Note that FIGS. 17A to 17I are diagrams showing an enlarged view of the first flow path 703, the nozzle 24, and the nozzle valve 26 in the cross-sectional view of the liquid discharge head 1 shown in FIG. 9. The description will be made with appropriate reference to FIGS. 9 and 16 as well.

[0140] First, as shown in FIG. 17A, the head cleaning device 150a lowers the liquid discharge head 1 toward the flow path member 702 (in the direction of arrow G70). Note that in the nozzle hole 240 shown in FIG. 17A, a thickened liquid 8a that closes the nozzle hole 240 is generated.

[0141] Subsequently, the head cleaning device 150a brings the liquid discharge head 1 into contact with the rubber member 701 of the capping unit 700. As a result, as shown in FIG. 17B, a sealed space is formed between the liquid discharge head 1 and the capping unit 700, and the first flow path 703 is formed in the sealed space by the nozzle surface 250 and the flow path member 702.

[0142] Subsequently, as shown in FIG. 17C, the head cleaning device 150a starts and continues to supply the second cleaning liquid 82 from the second cleaning liquid tank 830 to the liquid flow path 28 through the second supply unit 820. Arrow G71 indicates the direction in which the second cleaning liquid 82 flows in the liquid flow path 28. When the second cleaning liquid 82 is being supplied, the coating liquid 8 and the second cleaning liquid 82 are discharged to the second drainage tank 870 downstream of the liquid discharge head 1.

[0143] Subsequently, the head cleaning device 150a supplies the first cleaning liquid 80 from the first cleaning liquid tank 910 to the first flow path 703 through the first supply unit 800. As shown in FIG. 17D, when the first flow path 703 is filled with the first cleaning liquid 80, in other words, when the nozzle surface 250 is immersed in the first cleaning liquid 80, the head cleaning device 150a stops supplying the first cleaning liquid 80. During this time, the supply of the second cleaning liquid 82 to the liquid flow path 28 continues.

[0144] Subsequently, the head cleaning device 150a waits for a predetermined immersion time T while the supply of the first cleaning liquid is stopped. During this time, as shown in FIG. 17E, the coating liquid 8 in the nozzle 24 flows out or elutes into the first flow path 703 due to the diffusion action of the fluid. During this time, the supply of the second cleaning liquid 82 to the liquid flow path 28 continues.

[0145] Subsequently, as shown in FIG. 17F, the head cleaning device 150a drives the nozzle valve 26 and moves the nozzle valve 26 in the direction of arrow G72. As a result, the second cleaning liquid 82 in the liquid flow path 28 flows from the liquid flow path 28 into the nozzle 24. Arrow G73 indicates the direction in which the second cleaning liquid 82 flows from the liquid flow path 28 into the nozzle 24. In response to the outflow of the second cleaning liquid 82 into the nozzle 24, the coating liquid 8 in the nozzle 24 is discharged from the nozzle holes 240 into the first flow path 703. By this discharge operation, the liquid 8 in the nozzle 24 is discharged, and the thickened liquid 8a blocking the nozzle holes 240 is discharged.

[0146] Subsequently, as shown in FIG. 17G, the liquid 8 for coating flows out or elutes into the first flow path 703. Arrow G74 indicates the direction in which the liquid 8 for coating flows out or elutes into the first flow path 703.

[0147] At this time, when it is necessary to continuously cause the liquid 8 for coating in the nozzle 24 to flow out or elute, the head cleaning device 150a supplies the first cleaning liquid 80 from the first cleaning liquid tank 910 to the first flow path 703 again by the first supply unit 800. Arrow G75 indicates the direction in which the first cleaning liquid 80 flows in the first flow path 703. As shown in FIG. 17H, when the first flow path 703 is filled with the first cleaning liquid 80, in other words, when the nozzle surface 250 is immersed in the first cleaning liquid 80, the head cleaning device 150a stops the supply of the first cleaning liquid 80.

[0148] Subsequently, as shown in FIG. 17I, the liquid 8 for coating flows out or elutes into the first flow path 703. Arrow G76 indicates the direction in which the liquid 8 for coating flows out or elutes into the first flow path 703.

[0149] By the above procedure, the head cleaning device 150a can clean at least one of the nozzle 24 and the nozzle surface 250 of the liquid discharge head 1.

[0150] FIG. 18 is a flowchart showing a cleaning operation by the head cleaning device according to the second embodiment of the present invention. Note that operations similar to those described in FIG. 11 are appropriately omitted, and differences from FIG. 11 will be mainly described.

[0151] In step S62, the head cleaning device 150a supplies the second cleaning liquid 82 to the liquid discharge head 1 by the second supply unit 820 (see FIG. 17C). The head cleaning device 150a then continues to supply the second cleaning liquid 82 by the second supply unit 820 until the supply of the second cleaning liquid 82 is stopped.

[0152] Subsequently, in step S63, the head cleaning device 150a determines whether the liquid discharge head 1 can be cleaned by the supply of the second cleaning liquid. The completion of cleaning may be determined, for example, based on the supply time of the second cleaning liquid 82, or a sensor may be provided in the liquid flow path 28 and the determination may be made according to the detection result of the cleaning state by the sensor. Also at this time of determination, the supply of the second cleaning liquid 82 from the second cleaning liquid tank 830 to the liquid discharge head 1 continues. The fifth switching valve 880 downstream of the liquid discharge head 1 closes the valve so as to stop the discharge of the second cleaning liquid 82 to the second drainage tank 870.

[0153] Subsequently, in step S64, the head cleaning device 150a supplies the first cleaning liquid 80 to the capping unit 700 by the first supply unit 800 (see FIG. 17D).

[0154] Also, in step S67, the head cleaning device 150a executes the opening and closing operation of the nozzle valve 26. For example, the head cleaning device 150a opens the nozzle valve 26. By executing the opening and closing operation of the nozzle valve 26, at least one of the thickened liquid 8a and the air layer 8b can be discharged to the first flow path 703 (see FIG. 17F). Since the second cleaning liquid 82 is filled in the liquid flow path 28, the cleanability inside the nozzle 24 is improved by the discharge operation.

[0155] Also, in step S69, the head cleaning device 150a determines whether to supply the first cleaning liquid 80 to the first flow path 703 again in order to cause the liquid for coating inside the nozzle 24 to flow out or elute.

[0156] In step S69, if it is determined that supply is required (step S69, YES), the head cleaning device 150a closes the nozzle valve 26 in step S70. Thereafter, the operations after step S64 are performed again. On the other hand, if it is determined that supply is not required (step S69, NO), the head cleaning device 150a closes the nozzle valve 26 in step S71 in order to end the head cleaning operation. Thereafter, in step S72, for refreshing, the first supply unit 800 supplies the first cleaning liquid 80 to the first flow path 703. The head cleaning device 150a then continues to supply the first cleaning liquid 80 by the first supply unit 800 until the supply of the first cleaning liquid 80 stops.

[0157] Subsequently, in step S73, the head cleaning device 150a stops the supply of the first cleaning liquid 80 to the first flow path 703 by the first supply unit 800 and also stops the supply of the second cleaning liquid 82 to the liquid flow path 28 by the second supply unit 820.

[0158] Subsequently, in step S74, the head cleaning device 150a supplies air 90 to the first flow path 703 by the first compressor 920 to discharge the first cleaning liquid 80 in the first flow path 703, and supplies air to the liquid flow path 28 by the second compressor 840 to discharge the second cleaning liquid 82 in the liquid flow path 28.

[0159] The head cleaning device 150a can perform the cleaning operation according to the second embodiment of the present invention according to the procedure illustrated in FIG. 18. In the example shown in FIG. 18, after the cleaning of the liquid flow path 28 of the liquid ejection head 1 is completed, a procedure for cleaning at least one of the nozzle 24 and the nozzle surface 250 using the capping unit 700 is shown. However, the procedure of the cleaning operation according to the second embodiment of the present invention is not limited to this procedure. For example, the cleaning of the liquid flow path 28 of the liquid ejection head 1 and the cleaning of at least one of the nozzle 24 and the nozzle surface 250 using the capping unit 700 may be performed in parallel.

[0160] [Third Embodiment] Next, the flow path member of the head cleaning device according to the third embodiment of the present invention will be described. FIG. 19 is a diagram showing the flow path member 702 of the head cleaning device according to the third embodiment of the present invention.

[0161] In the third embodiment of the present invention, the main difference from the first embodiment is that the flow path member 702 includes a recess 704 that is arranged to face the nozzle hole 240 disposed on the nozzle surface 250 when the capping portion 700 forms a sealed space.

[0162] By arranging the recess 704, the flow path member 702 can hold a larger volume of the first cleaning liquid 80 in the region facing the nozzle hole 240 in the first flow path 703 than in the region other than the region facing the nozzle hole 240 in the first flow path 703. Thereby, in the flow path member 702, it is possible to prevent the liquid 8 for painting flowing out or eluting into the first flow path 703 from mixing with the first cleaning liquid 80 near the nozzle hole 240 and reducing the solubility. Further, by supplying the first cleaning liquid 80, a retention indicated by the arrow G80 occurs in the recess 704, so that in the flow path member 702, it is possible to further facilitate the elution of the liquid 8 for painting from the nozzle hole 240. Note that at least one of the recess 704 and the groove portion can be arranged at a position facing the nozzle hole 240 disposed on the nozzle surface 250. Further, the effects other than those described above in the third embodiment of the present invention are the same as the effects of the first embodiment of the present invention.

[0163] [Fourth Embodiment] Next, the flow path member of the head cleaning device according to the fourth embodiment of the present invention will be described. FIG. 20 is a diagram showing the flow path member 702 of the head cleaning device according to the fourth embodiment of the present invention.

[0164] In the fourth embodiment of the present invention, the main difference from the first embodiment is that the flow path member 702 includes a convex portion 705 that is arranged to face the nozzle hole 240 of the nozzle 24 when the capping portion 700 forms a sealed space.

[0165] The convex portion 705 has an inclined surface where the downstream side gradually becomes higher than the upstream side in the flowing direction of the first cleaning liquid 80 (the direction of arrow G90). The first cleaning liquid 80 that has passed through the position where the convex portion 705 is disposed easily flows toward the nozzle holes 240 according to the shape of the inclined surface. Thereby, in the flow path member 702, it is possible to easily discharge the liquid 8 for painting in the nozzle 24 to the first flow path 703. The effects other than the above in the fourth embodiment of the present invention are the same as the effects of the first embodiment of the present invention.

[0166] [Fifth Embodiment] Next, with reference to FIG. 21, the control unit 5 included in the head cleaning device according to the fifth embodiment of the present invention will be described. FIG. 21 is a block diagram showing a functional configuration of the control unit 5 included in the head cleaning device according to the fifth embodiment of the present invention. Note that the control unit 5 may further include a functional configuration other than the functional configuration shown in FIG. 21.

[0167] The control unit 5 shown in FIG. 21 includes a data storage unit 85, a learning unit 86, and an estimation unit 87. The functions of the data storage unit 85, the learning unit 86, and the estimation unit 87 may be realized by a machine learning program installed in the control unit 5.

[0168] (Example of updating the immersion time T by machine learning) The data storage unit 85 stores data including at least the number of filling times (α1, α2,...), the immersion time T, and the paint content of the cleaning liquid (in a state where the paint dissolved in the cleaning liquid is mixed) discharged from the capping to the drainage tank for each filling time. In addition, data on the number of cleaning times and the paint content for each of the plurality of immersion times T is also stored.

[0169] The learning unit 86 learns the relationship between the number of times (α1, α2,...) of filling the flow path between the head and the capping with the cleaning liquid and the paint content β of the discharged cleaning liquid after each filling based on the data stored in the data storage unit 85.

[0170] The learning unit 86 may generate a learned model 88 that learns the relationship between the filling times (α1, α2, ···) and the paint content β by using, as teacher data, a data set in which the filling times (α1, α2, ···) stored in the data storage unit 85 are associated with the paint content β, and cause the estimation unit 87 to hold the learned model 88.

[0171] The algorithm used in the learning unit 86 is not particularly limited, and deep learning using a neural network, an unsupervised learning model, a supervised learning model, a reinforcement learning model, or the like can be applied.

[0172] The estimation unit 87 estimates a predetermined value of the filling times (α1, α2, ···) based on the learning of the learning unit 86. For example, when a value indicating an acceptable filling time (α1, α2, ···) is input, the estimation unit 87 inputs the input value into the learned model 88 and estimates a predetermined value of the immersion time T output from the learned model 88.

[0173] The control unit 5 controls the time for immersing the cleaning liquid based on the predetermined value of the immersion time T estimated by the estimation unit 87.

[0174] By including the control unit 5 shown in FIG. 21, the head cleaning device according to the fifth embodiment of the present invention can adjust the immersion time T by using a learned model obtained by machine learning.

[0175] (Example of updating the number of nozzle openings / closing by machine learning) The data storage unit 85 stores data including at least the filling times (α1, α2, ···), the immersion time T, the paint content of the cleaning liquid (in a state where the cleaning liquid and the dissolved paint are mixed) discharged from the capping corresponding to each filling into the drain tank, and the number of nozzle openings. Also, data on the cleaning times and the paint content for each of the plurality of immersion times T are stored.

[0176] The learning unit 86 learns the relationship between the number of times the flow path between the head cappings is filled with the cleaning liquid (α1, α2, ···), the paint content β of the discharged cleaning liquid after each filling, and the number of times the nozzle is opened, based on the data stored in the data storage unit 85.

[0177] For example, the learning unit 86 may use, as teacher data, a data set in which the filling times (α1, α2, ···), the paint content β, and the number of times the nozzle is opened, stored in the data storage unit 85, are associated with each other, to generate a learned model 88 that has learned the relationship between the filling times (α1, α2, ···), the paint content β, and the number of times the nozzle is opened, and cause the estimation unit 87 to hold it.

[0178] The algorithm used in the learning unit 86 is not particularly limited, and deep learning using a neural network, an unsupervised learning model, a supervised learning model, a reinforcement learning model, etc. can be applied.

[0179] The estimation unit 87 estimates a predetermined value of the number of times the nozzle is opened, based on the learning of the learning unit 86. For example, when a value indicating an acceptable filling time (α1, α2, ···) is input, the estimation unit 87 inputs the input value to the learned model 88, and estimates a predetermined value of the immersion time T and the number of times the nozzle is opened, output from the learned model 88.

[0180] The control unit 5 controls the time for immersing the cleaning liquid, based on the immersion time T and the predetermined value of the number of times the nozzle is opened, estimated by the estimation unit 87.

[0181] By including the control unit 5 shown in FIG. 21, the head cleaning device according to the fifth embodiment of the present invention can adjust the immersion time T and the number of times the nozzle is opened, using a learned model by machine learning.

[0182] [Sixth Embodiment] Next, with reference to FIG. 22, the scanning method of the liquid ejection head 1 in the coating apparatus according to the sixth embodiment of the present invention will be described. FIG. 22 is a diagram showing the scanning method of the liquid ejection head 1 in the coating apparatus 100S according to the sixth embodiment of the present invention.

[0183] The coating apparatus 100S includes a head 11S, a first guide unit 800S that moves the head 11S in the main scanning direction (X-axis direction) of the head 11S, a fixed guide unit 810S that unitizes the head 11S and the first guide unit, and a second guide unit 820S that moves the head 11S in the vertical direction (Y-axis direction) intersecting the scanning direction. The coating apparatus 100S has the head 11S provided on a member other than the robot arm 13S.

[0184] As shown in FIG. 22, the head 11S of the coating apparatus 100S is provided on the carriage 311S of the first guide unit 800S and is movably provided in the left-right direction (scanning direction). Further, the head 11S and the first guide unit 800S are unitized by the fixed guide unit 810S and are movably provided in the vertical direction along the second guide unit 820S. Thereby, the head 11S can be scanned in a two-dimensional direction along the first guide unit 800S and the second guide unit 820S, and liquid can be applied to the object.

[0185] Note that the head 11S can be read as the liquid ejection head 1 shown in FIG. 6 described above. The coating apparatus 100S includes the head cleaning device 150 described above. The head cleaning device 150 can seal the head 11S by the capping unit 700 and clean at least one of the nozzle 24 and the nozzle surface 250 of the head 11S. The coating apparatus 100S can also include the head cleaning device 150a described above. The head cleaning device 150a can seal the head 11S by the capping unit 700 and clean at least one of the nozzle 24 and the nozzle surface 250 of the head 11S and the liquid flow path 28.

[0186] Although the preferred embodiments have been described in detail above, the present invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments of the present invention without departing from the scope described in the claims.

[0187] The numbers such as ordinal numbers and quantities used in the description of the embodiments of the present invention are all exemplified for specifically explaining the technology of the present invention, and the present invention is not limited to the exemplified numbers. Also, the connection relationship between components is exemplified for specifically explaining the technology of the present invention, and the connection relationship for realizing the functions of the present invention is not limited thereto.

[0188] Aspects of the present invention are, for example, as follows. <1> A head cleaning device including a liquid ejection head having a nozzle and a nozzle surface, a capping portion including a first flow path serving as a flow path for a first cleaning liquid, and a control portion for controlling the supply of the first cleaning liquid, wherein the control portion supplies the first cleaning liquid to the first flow path, stops the supply of the first cleaning liquid in a state where the nozzle surface is immersed, and after a predetermined immersion time has elapsed since the supply of the first cleaning liquid was stopped, supplies the first cleaning liquid again, and then controls to stop the supply of the first cleaning liquid. <2> The head cleaning device according to <1>, wherein the control portion causes the liquid ejection head to eject liquid in a state where the nozzle surface is immersed in the first cleaning liquid. <3> The head cleaning device according to <1> or <2>, wherein the shape of the surface of the first flow path facing the nozzle surface is a substantially flat shape. <4> The head cleaning device according to any one of <1> to <3>, wherein the first flow path includes at least one of a recess and a groove portion disposed opposite to a nozzle hole disposed on the nozzle surface when the capping portion forms a sealed space. <5> The head cleaning device according to any one of <1> to <4>, wherein the first flow path has a convex portion disposed opposite to a nozzle hole disposed on the nozzle surface when the capping portion forms a sealed space. <6> The head cleaning device according to any one of <1> to <5>, further comprising a vibration applying unit that applies vibration to the first cleaning liquid flowing through the first flow path. <7> The head cleaning device according to any one of <1> to <5>, further comprising a second supply unit that supplies a second cleaning liquid for cleaning a second flow path of the liquid discharge head to the liquid discharge head, and the control unit supplies the second cleaning liquid to the liquid discharge head by the second supply unit After cleaning the liquid discharge head, the first cleaning liquid is supplied to the first flow path of the capping unit by the first supply unit. <8> The liquid discharge head has a valve body that opens and closes a nozzle hole and a driving means that drives the valve body to open and close. When a sealed space is formed, the driving means drives the valve body to open and close. The head cleaning device according to any one of <1> to <7>. <9> The capping unit forms a sealed space by contacting the liquid discharge head. The head cleaning device according to any one of <1> to <8>. <10> The first flow path is disposed opposite to the nozzle surface in the sealed space of the capping unit. The head cleaning device according to any one of <1> to <9>. <11> A coating device having the head cleaning device according to any one of <1> to <10>. <12> A head cleaning method using a head cleaning device including a liquid discharge head having a nozzle and a nozzle surface, a capping unit including a first flow path that serves as a flow path for a first cleaning liquid, and a control unit that controls the supply of the first cleaning liquid. The control unit supplies the first cleaning liquid to the first flow path, stops the supply of the first cleaning liquid in a state where the nozzle surface is immersed, and after a predetermined immersion time has elapsed since the supply of the first cleaning liquid was stopped, the first cleaning liquid is supplied again, and then the supply of the first cleaning liquid is stopped. A head cleaning method for controlling as described above.

Explanation of symbols

[0189] 1 Liquid discharge head 2 Painting robot 3 Position detection unit 4 Liquid supply unit 5 Control unit 6 Liquid storage unit 7 Air supply unit 8 Liquid 8a Viscous liquid 8b Air layer 9 Air regulator 10 Base part 11 First arm 12 Second arm 13 Head unit 16 Encoder sensor 17 Robot drive unit 20 Housing 21 Supply port 22 Recovery port 23 Discharge module 24 Nozzle 240 Nozzle holes 25 Nozzle plate 250 Nozzle surface 26 Nozzle valve 27 Piezoelectric element 28 Liquid flow path (an example of the second flow path) 40 Maintenance and recovery unit 80 First cleaning liquid 81 Part 82 Second cleaning liquid 85 Data storage unit 86 Learning unit 87 Estimation unit 88 Learned model 90 Air 100, 100S Painting device 111, 112 Air flow path 150, 150a Head cleaning device 200 Object 300 Computer 301 RIP unit 302 Rendering unit 400 Controller 401 CPU 402 ROM 403 RAM 404 HDD / SSD 405 I / F 411 System control unit 412 Nozzle valve drive control unit 413 Discharge cycle signal generation unit 414 Memory control unit 415 Data storage unit 416 Robot control signal generation unit 417 First supply control unit 418 Second supply control unit 500 Head control device 600 Robot control device 700A Input device 700 Capping unit 701 Rubber member 702 Flow path member 703 First flow path 704 Recess 705 Protrusion 710 Movable plate 721 Spring 720 Substrate 730 Supply port 740 Drain port 800 First supply unit 810 Coating liquid tank 820 Second supply unit 830 Second cleaning liquid tank 831 Second supply pipe 840 Second compressor 850 Third switching valve 860 Fourth switching valve 870 Second drain tank 871 Second discharge pipe 880 Fifth switching valve 11S Head 311S Carriage 800S First guide part 810S Fixed guide part 820S Second guide part 910 First cleaning liquid tank 911 First supply pipe 920 First compressor 930 First switching valve 940 First Drain Tank 941 First Discharge Pipe 950 Second Switching Valve 820 Second Supply Unit Arrows A - F Arrows G10 - G12, G20 - G22, G30, G40 - G45, G50 - G57 Arrows G60 - G67, G70 - G76, G80, G90 - G91 S System Bus

Prior Art Documents

Patent Documents

[0190]

Patent Document 1

Claims

1. A nozzle, a nozzle surface, and a liquid ejection head including the same, a capping unit including a first flow path that serves as a flow path for a first cleaning liquid, a control unit that controls the supply of the first cleaning liquid, and the control unit supplies the first cleaning liquid to the first flow path, stops the supply of the first cleaning liquid in a state where the nozzle surface is immersed, and after a predetermined immersion time has elapsed since the supply of the first cleaning liquid was stopped, supplies the first cleaning liquid again, and then controls to stop the supply of the first cleaning liquid. A head cleaning device.

2. The control unit causes the liquid ejection head to eject liquid in a state where the nozzle surface is immersed in the first cleaning liquid. The head cleaning device according to claim 1.

3. The shape of the surface of the first flow path facing the nozzle surface is a substantially flat shape. The head cleaning device according to claim 1.

4. The first flow path includes at least one of a concave portion and a groove portion that are arranged to face a nozzle hole arranged on the nozzle surface when the capping unit forms a sealed space. The head cleaning device according to claim 1.

5. The first flow path has a convex portion that is arranged to face a nozzle hole arranged on the nozzle surface when the capping unit forms a sealed space. The head cleaning device according to claim 1.

6. The head cleaning device according to claim 1, further comprising a vibration applying unit that applies vibration to the first cleaning liquid flowing through the first flow path.

7. The head cleaning device further includes a second supply unit that supplies a second cleaning liquid for cleaning a second flow path of the liquid ejection head to the liquid ejection head, and after the control unit cleans the liquid ejection head by supplying the second cleaning liquid to the liquid ejection head by the second supply unit, the control unit supplies the first cleaning liquid to the first flow path of the capping unit by the first supply unit. The head cleaning device according to claim 1.

8. The liquid ejection head has a valve body that opens and closes a nozzle hole and a driving means that drives the valve body to open and close, and when a sealed space is formed, the driving means drives the valve body to open and close. The head cleaning device according to claim 1.

9. The capping unit forms a sealed space by contacting the liquid ejection head. The head cleaning device according to claim 1.

10. The first flow path is arranged to face the nozzle surface in the sealed space of the capping unit. The head cleaning device according to claim 1.

11. A painting apparatus having the head cleaning device according to any one of claims 1 to 10.

12. A nozzle, A liquid discharge head including a nozzle surface, A capping portion including a first flow path serving as a flow path for a first cleaning liquid, A head cleaning method by a head cleaning device including a control unit that controls the supply of the first cleaning liquid, wherein the head cleaning device Supplies the first cleaning liquid to the first flow path by the control unit, stops the supply of the first cleaning liquid in a state where the nozzle surface is immersed, and after a predetermined immersion time has elapsed since the supply of the first cleaning liquid was stopped, supplies the first cleaning liquid again, and then controls to stop the supply of the first cleaning liquid.

Images