Liquid discharge apparatus and liquid discharge method

Abstract

A liquid discharge apparatus includes: a discharge unit including nozzles from which liquid droplets are dischargeable to a target; a moving mechanism to relatively move at least one of the target and the discharge unit in a relative movement direction; and a control unit configured to control an amount of one droplet of the liquid droplets and a landing interval of the liquid droplets on the target in accordance with an incident angle of the one droplet of the liquid droplets with respect to a surface of the target at a landing position where the one droplet of the liquid droplets lands on the target.

Description

[DESCRIPTION][Title of Invention]LIQUID DISCHARGE APPARATUS AND LIQUID DISCHARGE METHOD [Technical Field]

[0001] The present embodiment relates to a liquid discharge apparatus and a liquid discharge method.[Background Art]

[0002] There is known a liquid discharge apparatus that discharges liquid droplets from a nozzle to attach the liquid to a target.

[0003] For example, Patent Literature (PTL) 1 (Japanese Patent No. 4792701) proposes a liquid discharge apparatus that, to increase a resolution at a discharge position, moves a discharge head obliquely with respect to a direction of a nozzle row to control a discharge timing of liquid droplets.

[0004] By the way, when liquid droplets are discharged in a direction oblique to a surface of a target, some of the liquid droplets discharged to the target may bounce back and become a mist, making it difficult to favorably attach the liquid to the target.[Summary of Invention][Problems to be Solved]

[0005] An object of the present embodiment is to suppress generation of a mist and to favorably attach a liquid to a target.[Solution to Problem]

[0006] In an aspect of the present disclosure, a liquid discharge apparatus is provided that includes: a discharge unit including nozzles from which liquid droplets are dischargeable to a target; a moving mechanism to relatively move at least one of the target and the discharge unit in a relative movement direction; and a control unit configured to control an amount of one droplet of the liquid droplets and a landing interval of the liquid droplets on the target in accordance with an incident angle of the one droplet of the liquid droplets with respect to a surface of the target at a landing position where the one droplet of the liquid droplets lands on the target.In another aspect of the present disclosure, a liquid discharge apparatus is provided that includes: a discharge unit including nozzles to discharge liquid droplets to a target, the nozzles arrayed with an interval in an array direction; a moving mechanism to relatively move at least one of the target and the discharge unit; and a control unit configured to: cause the discharge unit to discharge the liquid droplets to the target; control a landing interval betweenthe liquid droplets adjacent to each other on the target to be smaller than the interval of the nozzles in the array direction; and control the liquid droplets landing adjacent to each other to be partially overlapped with each other, when an incident angle of the liquid droplets, at a landing position where the liquid droplets land on the target, is a predetermined angle larger than 0°.In further another aspect of the present disclosure, a liquid discharge method is provided that includes: discharging liquid droplets from nozzles to a target; and controlling an amount of one droplet of the liquid droplets and a landing interval of the liquid droplets on the target in accordance with an incident angle of the liquid droplets of the liquid droplets with respect to a surface of the target at a landing position where the liquid droplets land on the target to discharge the liquid droplets to the target.[Effects of the Invention]

[0007] According to the present embodiment, it is possible to suppress generation of a mist and to favorably attach a liquid to a target.[Brief Description of Drawings]

[0008] A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings.[FIG. 1]FIG. 1 illustrates an overall configuration of a liquid discharge apparatus according to a first embodiment of the present embodiment.[FIG. 2]FIG. 2 illustrates a more specific configuration of a liquid supply unit according to the first embodiment of the present embodiment.[FIG. 3]FIG. 3 is a perspective view of a discharge unit according to the first embodiment of the present embodiment.[FIG. 4]FIG. 4 is a cross-sectional view of the discharge unit according to the first embodiment of the present embodiment.[FIG. 5]FIG. 5 illustrates an aspect in which coating is performed in a state where a nozzle surface of the discharge unit is inclined with respect to a surface of a target.[FIG. 6]FIG. 6 illustrates a relationship between an incident angle and a mist amount.[FIGS. 7 A, 7B, and 7C]FIGS. 7A, 7B, and 7C illustrate a liquid discharge method according to the first embodiment of the present embodiment.[FIG. 8]FIG. 8 is a block diagram illustrating a hardware configuration of a coating system according to the first embodiment of the present embodiment.[FIG. 9]FIG. 9 illustrates a generation flow of coating data according to the first embodiment of the present embodiment.[FIG. 10]FIG. 10 illustrates a coating flow according to the first embodiment of the present embodiment.[FIG. 11]FIG. 11 is a block diagram illustrating another hardware configuration of the coating system.[FIG. 12]FIG. 12 illustrates a coating flow according to the other hardware configuration.[FIGS. 13A, 13B, 13C, and 13D]FIGS. 13A, 13B, 13C, and 13D illustrate a liquid discharge method according to a second embodiment of the present embodiment.[FIG. 14]FIG. 14 illustrates an example in which an incident angle is different for each nozzle.[FIG. 15]FIG. 15 illustrates an example of a determination criterion for an incident angle.[FIG. 16]FIG. 16 illustrates a center of an arrayed range of nozzles when the nozzles are arranged in a zigzag manner in two rows.[FIGS. 17 A and 17B]FIGS. 17A and 17B illustrate a change in an interval between nozzles in a movement orthogonal direction when a discharge unit having the nozzles arranged in a zigzag manner is inclined with respect to a movement direction X.[FIG. 18]FIG. 18 is a block diagram of a control unit having a machine learning function.[FIG. 19]FIG. 19 illustrates an example of another liquid discharge apparatus to which it is possible to apply the present embodiment.[FIG. 20]FIG. 20 illustrates an example of still another liquid discharge apparatus to which it is possible to apply the present embodiment.The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views. [Description of Embodiments]In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.Referring now to the drawings, embodiments of the present disclosure are described below. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0009] Hereinafter, some embodiments will be described with reference to some accompanying drawings. Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views thereof, a liquid discharge apparatus according to an embodiment of the present disclosure is described below.

[0010] Overall Configuration of Liquid discharge apparatusAn overall configuration of a liquid discharge apparatus according to a first embodiment of the present embodiment will now first be described with reference to FIG. 1.

[0011] A coating device 100 that discharges liquid droplets to a vehicle body of an automobile representing a target 200 to perform coating on the vehicle body is exemplified herein as an example of a liquid discharge apparatus. The target 200 may be a body of an aircraft, a hull of a ship, or another three-dimensional structure, instead of the vehicle body of the automobile.

[0012] As illustrated in FIG. 1, the coating device 100 according to the first embodiment of the present embodiment includes four coating robots 2.

[0013] The coating robots 2 each include a base portion 10 installed on a floor surface, a first arm 11 provided to the base portion 10, a second arm 12 coupled to the first arm 11, and a head unit 13 provided at a distal end of the second arm 12, for example. The first arm 11 and the second arm 12 of the coating robot 2 are robot arms rotatably and swingably coupled to each other via joint portions, and function as moving mechanisms that are rotation-driven or swing- driven to move the head unit 13 to a desired position.

[0014] Specifically, the first arm 11 is provided to be rotatable in directions indicated by arrows A illustrated in FIG. 1 and to be swingable in directions indicated by arrows B with respect to the base portion 10. The second arm 12 is provided to be rotatable in directions indicated by arrows C illustrated in FIG. 1 and to be swingable in directions indicated by arrows D with respect to a distal end of the first arm 11. The head unit 13 is attached to be rotatable in directions indicated by arrows E illustrated in FIG. 1 and to be swingable in directionsindicated by arrows F with respect to the distal end of the second arm 12. A number of the coating robots 2 is not limited to four, and may be one, two, three, or five or more.

[0015] The head unit 13 includes a discharge unit 1 that discharges liquid droplets and a position detection unit 3 that detects a position of the target 200. The discharge unit 1 includes a plurality of nozzles for discharging liquid droplets. The position detection unit 3 is attached to the distal end of the second arm 12 integrally with the discharge unit 1. The position detection unit 3 includes, for example, a stereo camera that detects three-dimensional positional information of three or more feature points on the target 200. The stereo camera includes a plurality of cameras. The position detection unit 3 uses a triangulation method based on parallax between images captured by the plurality of cameras to acquire a distance image of the target 200.

[0016] The coating device 100 according to the first embodiment of the present embodiment includes a liquid supply unit 4 and a control unit 5, in addition to the coating robots 2.

[0017] 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 internally stores a liquid 8 such as paint. The air supply unit 7 is, for example, a compressor 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 liquid storage unit 6 is internally pressurized. The liquid 8 in the liquid storage unit 6 is supplied to the discharge unit 1, and discharged as liquid droplets from the nozzles of the discharge unit 1. In addition to liquid droplets, the discharge unit 1 is also able to discharge a liquid in a threadlike manner. Although FIG. 1 illustrates only a path through which the liquid 8 is supplied to one of the discharge units 1, the liquid 8 is similarly supplied from the liquid storage unit 6 to all the discharge units 1. A plurality of the liquid storage units 6 that stores liquids that are different in color or type from each other may be prepared to make it possible to switch and supply the liquids that are different in color or type from each other to each of the discharge units 1.

[0018] The control unit 5 is configured to control an operation of each of the coating robots 2 and discharge operation of each of the discharge units 1 based on positional information of the target 200, which is detected by each of the position detection units 3, in addition to shape data of the target 200 and image data for coating, which are inputted in advance. As a result, the head units 13 are moved along a shape of the target 200. Liquid droplets are thus discharged from the discharge units 1 to a surface of the target 200. Although FIG. 1 only illustrates a signal line from the control unit 5 to one of the coating robots 2 and one of the discharge units 1 and a signal line from one of the position detection units 3 to one of the control units 5, the control unit 5 controls operation of all the coating robots 2 and all the discharge units 1 and receives detection signals from all the position detection units 3.

[0019] FIG. 2 is a view illustrating a more specific configuration of the liquid supply unit 4 according to the first embodiment of the present embodiment.

[0020] As illustrated in FIG. 2, the liquid supply unit 4 includes a plurality of air regulators 9, in addition to the liquid storage unit 6 and the air supply unit 7. The air regulators 9 are provided in an air flow path 111 coupling the air supply unit 7 and a plurality of the liquid storage units 6. The air regulators 9 adjust air pressure at which air is supplied from the air supply unit 7 to each of the liquid storage units 6. The plurality of liquid storage units 6 is each individually coupled to each of the discharge units 1 via each of air flow paths 112. When each of the liquid storage units 6 is internally pressurized, the liquid 8 is supplied from each of the liquid storage units 6 to each of the discharge units 1. The liquid storage units 6 may not be each provided for each of the discharge units 1. However, there may be one liquid storage unit provided in common for all the discharge units 1.

[0021] Configuration of Discharge unitNext, a configuration of the discharge unit 1 according to the first embodiment of the present embodiment will now be described with reference to FIGS. 3 and 4. FIG. 3 is a perspective view of the discharge unit 1 according to the first embodiment of the present embodiment. FIG. 4 is a cross-sectional view of the discharge unit 1 according to the first embodiment of the present embodiment.

[0022] As illustrated in FIG. 3, the discharge unit 1 includes a housing 20, and a supply port 21 and a collection port 22 provided in the housing 20.

[0023] As illustrated in FIG. 4, a plurality of discharge modules 23 is arranged in a row or a plurality of rows in the housing 20. The discharge modules 23 each include 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 to discharge liquid droplets for the discharge modules 23, respectively. The nozzles 24 are openable by the nozzle valves 26. The piezoelectric element 27 is a driving means that expands and contracts when a voltage is applied to open and close the nozzle valve 26. The liquid flow paths 28 communicate with each other among the discharge modules 23 to form a common flow path. The liquid flow paths 28 also communicate with the supply port 21 and the collection port 22.

[0024] When a liquid is supplied from the supply port 21 into the housing 20 in a state where a valve of the collection port 22 is closed, the liquid flows into the liquid flow paths 28 and is pressurized. When no voltage is applied to the piezoelectric element 27 at this time, the nozzle 24 is closed by the nozzle valve 26. The nozzle 24 discharges no liquid droplets. When a voltage is applied to the piezoelectric element 27, the nozzle valve 26 is driven. Thenozzle 24 is opened. Liquid droplets are discharged from the nozzle 24. The liquid that has not been discharged from the nozzle 24 is discharged to outside through the collection port 22.

[0025] Problem of Mist generated during CoatingA mist generated during coating will now be described herein with reference to the configuration of the first embodiment of the present embodiment as an example.

[0026] In a configuration in which it is possible to move the discharge unit 1 by the coating robot 2 to discharge liquid droplets at a desired angle, similar to the first embodiment of the present embodiment, it is possible to dispose a nozzle surface (also referred to as the nozzle plate 25 illustrated in FIG. 4) of the discharge unit 1 in parallel to the surface of the target 200. It is thus possible to favorably perform coating. When coating is to be performed on a three- dimensional structure having a complicated shape such as a vehicle body, there may be a case where it is necessary to perform coating in a state where a nozzle surface 15 of the discharge unit 1 is inclined with respect to a surface 201 of the target 200, as illustrated in FIG. 5. In this case, some of liquid droplets 29 discharged to the target 200 bounce back and become a mist, making it difficult to favorably attach the liquid to the target 200. In a portion where it is necessary to perform coating in a state where the nozzle surface 15 is inclined with respect to the surface 201 of the target 200, it may be difficult to favorably perform coating due to a generated mist, possibly deteriorating coating quality.

[0027] An amount of a mist generated due to liquid droplets that bounce back varies depending on an incident angle of the liquid droplets with respect to the surface of a target. The "incident angle" refers to an angle a illustrated in FIG. 5, and means an inclination in a landing direction of the liquid droplets 29 or a normal direction of the nozzle surface 15 with respect to a normal direction of the surface 201 of the target 200 at a landing position where the liquid droplets 29 land.

[0028] FIG. 6 illustrates a relationship between the incident angle and the mist amount.

[0029] In FIG. 6, three graphs indicated by a solid line, an alternate long and short dash line, and an alternate long and two short dashes line illustrate the relationships between the incident angle and the mist amount when a liquid amount (a volume) of one droplet discharged from the nozzle is different.Among the three graphs, the solid line indicates a case where the liquid amount of one droplet is largest, the alternate long and short dash line indicates a case where the liquid amount is second largest, and the alternate long and two short dashes line indicates a case where the liquid amount is smallest. According to the relationships illustrated in FIG. 6, the mist amount tends to increase as the incident angle increases in all the cases. Even at an identicalincident angle, the mist amount increases when the liquid amount of one droplet is larger than when the liquid amount of one droplet is smaller. The mist amount also varies depending on the liquid amount of one droplet, in addition to the incident angle. That is, the larger the incident angle, the more the mist to be generated. The more the liquid amount of one droplet, the more the mist to be generated.

[0030] As described above, the mist tends to increase due to an increase in incident angle or an increase in liquid amount of one droplet. When focusing on this relationship, it can be said, that reducing a liquid amount of one droplet makes it possible to reduce a mist amount. If a liquid amount of one drop is simply reduced, an amount of the liquid to be discharged to the target is reduced. Other problems thus rise such as a reduced thickness of a coating film and an exposed base.

[0031] In the present embodiment, a liquid discharge method described below is proposed to allow a liquid to be favorably attached to a target while suppressing a mist. The liquid discharge method according to the first embodiment of the present embodiment will now be described herein.

[0032] Liquid discharge method According to First Embodiment of Present Embodiment FIGS. 7A, 7B, and 7C are views illustrating a liquid discharge method according to the first embodiment of the present embodiment.

[0033] FIGS. 7A-1 to 7A-3 illustrate an inclination p (pi) of a nozzle row, a landing area S (SI) of each of the liquid droplets 29, and landing intervals Px and Py (Pxl and Pyl) of the liquid droplets 29 when the incident angle a is al (for example, 0°). FIGS. 7B-1 to 7B-3 illustrate an inclination P (P2) of the nozzle row, a landing area S (S2) of each of the liquid droplets 29, and landing intervals Px and Py (Px2 and Py2) of the liquid droplets 29 when the incident angle a is an angle a2 that is larger than the incident angle al. Similarly, FIGS. 7C-1 to 7C- 3 illustrate an inclination p (P3) of the nozzle row, a landing area S (S3) of each of the liquid droplets 29, and landing intervals Px and Py (Px3 and Py3) of the liquid droplets 29 when the incident angle a is an angle a3 that is larger than the incident angle a2. In each of FIGS. 7A, 7B, and 7C, drawings indicated as <Incident Angle> are side views of the discharge unit 1 as viewed from a side. Drawings indicated as inclination of Nozzle Row> are plan views of the discharge unit 1 as viewed from above. Drawings indicated as <Landing Area and Landing Interval > are plan views of landing portions of the liquid droplets 29 on the surface 201 of the target 200 as viewed from above.

[0034] The "inclination p of the nozzle row" refers to an inclination of an array direction of the nozzles 24 with respect to a movement direction X of the discharge unit 1 when the discharge unit 1 moves along the surface 201 of the target 200. The array direction of the nozzles 24refers to, when the nozzles 24 are arranged in a zigzag or latticed pattern other than in one row, a direction in which the nozzles 24 are arranged longest.

[0035] The "landing area S of each of the liquid droplets 29" refers to an area where one droplet of the liquid droplets 29 lands on the surface 201 of the target 200. The "landing intervals Px and Py of the liquid droplets 29" refers to landing intervals of the liquid droplets 29 adjacent to each other, and include the landing interval Px in the movement direction X of the discharge unit 1 and the landing interval Py in a movement orthogonal direction Y that is orthogonal to the movement direction X.

[0036] In the first embodiment of the present embodiment, as illustrated in FIGS. 7A, 7B, and 7C, the landing area S of each of the liquid droplets 29 is caused to decrease (SI > S2 > S3), as the incident angle a increases (al < a2 < a3). That is, since a mist may easily occur as the incident angle a increases (FIG. 6), the liquid amount of one droplet is reduced to decrease the landing area S of each of the liquid droplets 29, when the incident angle a is large. It is possible to adjust the amount of each of the liquid droplets 29 by allowing a nozzle valve drive control unit 402 illustrated in FIG. 8 to change any one or two or more of an opening time of each of the nozzles 24, an opening amount of each of the nozzles 24, and discharge pressure for the liquid droplets 29. When the incident angle a is large, the nozzle valve drive control unit 402 is allowed to perform any one or two or more of shortening of the opening time of each of the nozzles 24, reduction of the opening amount of each of the nozzles 24, and reduction of the discharge pressure for the liquid droplets 29 to reduce the amount of each of the liquid droplets 29. As a result, it is possible to reduce the mist amount.

[0037] If the amount of each of the liquid droplets 29 is simply reduced, the amount of the liquid to be discharged to the target 200 is also reduced. When the incident angle a is large in the first embodiment of the present embodiment, the landing intervals Px and Py of the liquid droplets 29 are also shortened (Pxl > Px2 > Px3 and Pyl > Py2 > Py3).In this case, both the landing interval Px in the movement direction X and the landing interval Py in the movement orthogonal direction Y are shortened.

[0038] It is possible to adjust the landing interval Px in the movement direction X by changing at least one of a movement speed of the discharge unit 1 moved by a robot control device 600 illustrated in FIG. 8 and a time interval at which the liquid droplets 29 adjacent to each other illustrated in FIGS. 7A, 7B, and 7C are discharged from the discharge unit 1 by a head control device 500 illustrated in FIG. 8. When the incident angle a is large, it is possible to shorten the landing interval Px in the movement direction X (Pxl > Px2 > Px3) by performing any one or both of reduction of the movement speed of the discharge unit 1 and shortening of the time interval at which the liquid droplets 29 are discharged. Even when a number of thenozzles 24 is not plural, but singular, it is possible to adjust the landing interval Px in the movement direction X in a similar manner.

[0039] It is possible to change the landing interval Py in the movement orthogonal direction Y by changing the inclination [1 of the nozzle row, as illustrated in FIGS. 7A, 7B, and 7C. When the incident angle a is large, the robot control device 600 controls an orientation of the discharge unit 1 to reduce the inclination P of the nozzle row (pi > P2 > P3), making it possible to shorten the landing interval Py in the movement orthogonal direction Y (Pyl > Py2 > Py3).

[0040] In the first embodiment of the present embodiment, as described above, when the incident angle a is large, the head control device 500 reduces the amount of one droplet of the liquid droplets 29 and shortens the landing intervals Px and Py of the liquid droplets 29 to discharge the liquid droplets 29. As a result, when the incident angle a is large, the amount of one droplet of the liquid droplets 29 is reduced to suppress a mist. As a result, even if the landing area S of one droplet of the liquid droplets 29 is reduced, shortening the landing intervals Px and Py among the liquid droplets 29 makes it possible to secure an adhesion amount of the liquid per unit area. According to the first embodiment of the present embodiment, it is possible to favorably secure a thickness of a coating film without allowing a base to be exposed. It is thus possible to implement suppression of a mist and favorable adhesion of a liquid, improving coating quality.

[0041] In the first embodiment of the present embodiment, the landing intervals Px and Py in both the movement direction X and the movement orthogonal direction Y of the discharge unit 1 are shortened. However, only one of the landing intervals may be shortened. Even in this case, it is possible to increase an adhesion amount of a liquid per unit area. It is thus possible to expect improvement in coating quality. To more securely prevent coating defects and improve coating quality, it is preferable to shorten the landing intervals Px and Py in both the movement direction X and the movement orthogonal direction Y.

[0042] In the first embodiment of the present embodiment, the landing area S and the landing intervals Px and Py are changed in two stages from FIG. 7A to FIG. 7B and from FIG. 7B to FIG. 7C, as the incident angle a increases, as illustrated in FIGS. 7A, 7B, and 7C. However, a response to such an increase may be made by a change in only one stage. That is, in both a case of FIG. 7B where the incident angle a is larger than the incident angle a illustrated in FIG. 7A and a case of FIG. 7C where the incident angle a is larger than the incident angle a illustrated in FIG. 7A, the landing area S and the landing intervals Px and Py may be changed in only one stage, similar to the aspect illustrated in FIG. 7C, for example. Even in such a case, it is possible to secure an adhesion amount of a liquid per unit area while suppressing a mist. If the landing area S and the landing intervals Px and Py are changed to the landingarea S and the landing intervals Px and Py in the aspect illustrated in FIG. 7C, in a case where the incident angle a is the incident angle a illustrated in FIG. 7B, however, a coating area per unit time is reduced, compared with a case where the landing area S and the landing intervals Px and Py are the landing area S and the landing intervals Px and Py in the aspect illustrated in FIG. 7B. There is thus such a concern that a coating time extends longer. To efficiently perform coating while securing coating quality, it is preferable to change the landing area S and the landing intervals Px and Py in two or more stages in accordance with a magnitude of the incident angle a, similar to the first embodiment of the present embodiment.

[0043] Hardware Configuration of Coating SystemFIG. 8 is a block diagram illustrating a hardware configuration of a coating system according to the first embodiment of the present embodiment.

[0044] As illustrated in FIG. 8, a coating system 1000 according to the first embodiment of the present embodiment includes, in addition to the plurality of coating robots 2, an input device 700, a computer 300, a controller 400, the head control device 500, and the robot control device 600. Only the two coating robots 2 are displayed in here, and the remaining coating robots 2 are omitted.

[0045] Each of the coating robots 2 includes encoder sensors 16 and a robot drive unit 17. The encoder sensors 16 are, for example, optical sensors that each optically detect a slit of each of encoders provided in a coupling portion between the base portion 10 and the first arm 11, a coupling portion between the first arm 11 and the second arm 12, and a coupling portion between the second arm 12 and the head unit 13 of the coating robot 2. Since it is possible to grasp a rotation amount and a swing amount of each of the first arm 11, the second arm 12, and the head unit 13 through detection by the encoder sensors 16, it is possible to acquire three-dimensional positional information of the head unit 13. The robot drive unit 17 is a drive unit that performs rotating operation and swinging operation of the first arm 11, the second arm 12, and the head unit 13.

[0046] The input device 700 is a device to which information regarding the shape data of the target 200, image data for coating, coordinate data, a coating mode, a coating range (a coating start position and a coating end position), and a coating instruction is to be inputted. The input device 700 includes a keyboard, a mouse, and a touch panel with which a user performs input operation, for example. Various pieces of information inputted in the input device 700 are transmitted to the computer 300.

[0047] The computer 300 includes a routing information protocol (RIP) unit 301 that performs image processing on the image data received from the input device 700 and a rendering unit 302 that decomposes the image data into coating data used for each scan by each of the head units 13.The computer 300 receives the shape data of the target 200 from the input device 700, acquires actual positional information of the target 200, which is detected by the position detection unit 3, and generates a coating route for each of the coating robots 2 based on the shape data and the actual positional information of the target 200. The computer 300 calculates an incident angle a for liquid droplets with respect to the target 200 in the generated coating route. The incident angle a is calculated by using any one of the shape data of the target 200, which is received from the input device 700, the positional information of the target 200, which is detected by the position detection unit 3, and the three-dimensional positional information of the head units 13, which is detected by the encoder sensors 16, or a plurality of these pieces of information.

[0048] The controller 400, the head control device 500, and the robot control device 600 function as the control unit 5 that controls operation of each of the coating robots 2 and discharge operation of each of the discharge units 1. In this case, one head control device 500 and one robot control device 600 are provided. However, the head control device 500 and the robot control device 600 may be individually provided for each of the coating robots 2.

[0049] The controller 400 includes a system control unit 401, the nozzle valve drive control unit 402, a discharge cycle signal generation unit 403, a memory control unit 404, a data storage unit 405, and a robot control signal generation unit 406. The system control unit 401 receives the coating data and a command signal from the computer 300, and controls entire operation of the coating system 1000. The system control unit 401 may include functions of the RIP unit 301 and the rendering unit 302 included in the computer 300. The nozzle valve drive control unit 402 generates a control signal for controlling opening-and-closing drive of each of the nozzle valves 26 based on the coating data and the incident angle a received from the computer 300. The discharge cycle signal generation unit 403 generates a discharge cycle signal for each of the discharge units 1 based on an output signal from each of the encoder sensors 16 and the coating data and the incident angle a received from the computer 300.The memory control unit 404 controls the data storage unit 405. The data storage unit 405 includes memories such as a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD), and stores the coating data and coating range data received from the computer 300. The robot control signal generation unit 406 generates a synchronization control signal for achieving matching between driving and liquid droplet discharge operation of each of the coating robots 2 based on information of the coating data and the coating route provided from the computer 300. The robot control signal generation unit 406 generates a control signal for determining an inclination P of the nozzle row of each of the discharge units 1 based on the incident angle a calculated by the computer 300.

[0050] The head control device 500 receives the control signal from the nozzle valve drive control unit 402 and the discharge cycle signal from the discharge cycle signal generation unit 403,and controls a discharge amount and a discharge timing for each of the discharge units 1 based on the received control signal and the received discharge cycle signal. At this time, as the discharge amount and the discharge timing for each of the discharge units 1 are controlled based on the incident angle a, an amount of liquid droplets to be discharged and a landing interval Px in the movement direction X are controlled to an amount of liquid droplets and a landing interval in accordance with the incident angle a.

[0051] The robot control device 600 receives the control signal from the robot control signal generation unit 406, and controls driving of the robot drive unit 17 based on the received synchronization control signal. At this time, as the robot drive unit 17 is controlled based on the incident angle a, the inclination 0 of the nozzle row of each of the discharge units 1 is controlled. The landing interval Py in the movement orthogonal direction Y is then controlled to a landing interval in accordance with the incident angle a.

[0052] Generation Flow of Coating DataNext, a generation flow of coating data according to the first embodiment of the present embodiment will now be described herein with reference to FIG. 9.

[0053] When generation of coating data is started, as illustrated in FIG. 9, the computer 300 reads data regarding the target 200 from the input device 700. Coating data is then generated for each piece of the read data in a step Si l. As a result, operation of each of the coating robots 2 and discharge operation of each of the discharge units 1 are set based on the coating data.

[0054] The computer 300 calculates an incident angle a for liquid droplets with respect to the target 200 based on the coating data in a step S 12. As a result, when there is a coating portion where the incident angle a is equal to or larger than a threshold T that is set in advance, the coating data is corrected to reduce an amount of liquid droplets to be discharged and to shorten the landing interval at the coating portion in steps S13 and S14. That is, when the amount and the landing interval of liquid droplets are changed, operation of each of the coating robots 2 and discharge operation of each of the discharge units 1 are changed. The coating data is thus corrected in accordance with the operation after the amount and the landing interval are changed. At a coating portion where the incident angle a is smaller than the threshold T, the amount and the landing interval of liquid droplets to be discharged are not changed. The coating data already generated is used. As described above, generation of coating data is completed.

[0055] Coating FlowNext, a coating flow according to the first embodiment of the present embodiment will now be described herein with reference to FIG. 10.

[0056] When coating is started, as illustrated in FIG. 10, the controller 400 acquires coating data generated by the computer 300 in a step S21. Next, the controller 400 controls each of the coating robots 2 based on the acquired coating data, and causes the coating robot 2 to move the discharge unit 1 to the coating portion on the target 200.

[0057] The controller 400 confirms the incident angle a at the coating portion from the acquired coating data. As a result, when the incident angle a is smaller than the predetermined threshold T in a step S22, liquid droplets are discharged in the aspect of FIG. 7A, for example. When the incident angle a is equal to or larger than the predetermined threshold T in the step S22, liquid droplets are discharged to reduce an amount of each of the liquid droplets to be discharged and to shorten the landing interval, compared with a case where the incident angle a is smaller than the threshold T in a step S23. For example, liquid droplets are discharged in the aspect illustrated in FIG. 7B or 7C. Thereafter, similarly, the incident angle a is confirmed by the controller 400, and an amount of one droplet of the liquid droplets and the landing interval of the liquid droplets are controlled in accordance with the incident angle a for each coating portion that is a movement destination of each of the discharge units 1.

[0058] Other Hardware ConfigurationFIG. 11 is a block diagram illustrating another hardware configuration of the coating system.

[0059] The hardware configuration that the coating system according to the present embodiment has may be such a hardware configuration as illustrated in FIG. 11. The hardware configuration illustrated in FIG. 11 is different from the example illustrated in FIG. 8 in that the position detection unit 3 detects positional information of the target 200 in a real time manner, and the detected positional information does not pass through the computer 300, but is directly inputted to the head control device 500 and the robot control device 600.

[0060] When coating is started, as illustrated in FIG. 12, in this case, the controller 400 first acquires coating data generated by the computer 300 in a step S31. A generation flow of coating data is identical to the flow illustrated in FIG. 9. Its description is thus omitted. Next, the controller 400 controls each of the coating robots 2 based on the acquired coating data, and causes the coating robot 2 to move the discharge unit 1 to the coating portion on the target 200.

[0061] When the discharge unit 1 moves to the coating portion on the target 200, the position detection unit 3 acquires positional information of the coating portion in a real time manner in a step S32. The acquired positional information is then directly inputted to the head control device 500 and the robot control device 600. The head control device 500 and the robot control device 600 control operation of the coating robots 2 and the discharge units 1 based onthe inputted positional information. When the incident angle a at the coating portion is equal to or larger than the predetermined threshold T at this time in a step S33, liquid droplets are discharged to reduce an amount of each of the liquid droplets to be discharged and to shorten the landing interval, compared with a case where the incident angle a is smaller than the threshold T in a step S34. Thereafter, similarly, an amount of one droplet of the liquid droplets and the landing interval of the liquid droplets are controlled in accordance with the incident angle a for each coating portion that is a movement destination of the discharge unit 1.

[0062] Second Embodiment of Present EmbodimentFIGS. 13A, 13B, 13C, and 13D illustrate a liquid discharge method according to a second embodiment of the present embodiment.

[0063] In the second embodiment of the present embodiment, as illustrated in FIGS. 13A, 13B, 13C, and 13D, as the incident angle a increases from al to a2, a3, and a4, the head control device 500 controls the discharge amount and the discharge interval of each of the discharge units 1. The robot control device 600 controls the orientation of each of the discharge units 1 to change the landing area S of each of and the landing intervals Px and Py of the liquid droplets 29 in three stages in accordance with the incident angles a2 to a4. The inclination p of the nozzle row is also changed from pi in three stages of 2, 03, and 4. As described above, changing the landing area S and the landing intervals Px and Py in three stages in accordance with the incident angles a2 to a4 makes it possible to perform more efficient coating while securing coating quality.

[0064] When the incident angle a is 0°, in the second embodiment of the present embodiment, as illustrated in FIG. 13 A, the nozzle row is arranged in the orientation of 90° with respect to the movement direction X of the discharge unit 1. When the incident angle a is 0°, as described above, the inclination of the nozzle row may be 90°. Setting the inclination p of the nozzle row to 90° makes it possible to widely secure the landing interval Py particularly in the movement orthogonal direction Y, making it possible to perform efficient coating.

[0065] In short, when the incident angle a is equal to a predetermined angle larger than 0° (the case other than FIGS. 7A and 13A), in both the embodiments illustrated in FIGS. 7A, 7B, and 7C and the embodiments illustrated in FIGS. 13A, 13B, 13C, and 13D, in the present embodiment, the liquid droplets 29 are discharged from the nozzles 24 in a state where the discharge unit 1 is inclined with respect to the movement direction X. That is, in the cases of FIGS. 7B and 7C and in the cases of FIGS. 13B, 13C, and 13D, the liquid droplets 29 are discharged to allow the interval Py in the movement orthogonal direction Y between the liquid droplets 29 that land adjacent to each other on a coating surface of the target 200 to be shorter than an interval G (illustrated in FIGS. 7A, 7B, and 7C and 13A, 13B, 13C, and 13D)in the array direction between the nozzles 24 that discharge the liquid droplets 29, and to allow the liquid droplets 29 that land adjacent to each other to partially overlap each other. As a result, it is possible to secure an adhesion amount of the liquid per unit area and to improve coating quality.

[0066] The "interval G in the array direction between the nozzles 24 that discharge the liquid droplets 29" means an interval in the array direction between the nozzles 24 arranged adjacent to each other among the nozzles 24 that actually discharge liquid droplets. When the liquid droplets 29 are discharged from only some of the nozzles 24, the interval Py in the movement orthogonal direction Y between the liquid droplets 29 that land adjacent to each other is allowed to be shorter than the interval G in the array direction between the nozzles 24 arranged adjacent to each other in the some of the nozzles 24.

[0067] Determination Criterion for Incident AngleNext, an example of a determination criterion for the incident angle a will now be described herein.

[0068] When the surface 201 of the target 200 is a curved surface, as illustrated in FIG. 14, for example, the incident angles al to a4 of the nozzles 24 may be different from each other. In such a case, it is difficult to change the inclination 0 of the nozzle row for each of the incident angles al to a4. It is necessary to determine an incident angle a0 as a reference for setting the inclination 0 of the nozzle row.

[0069] If the incident angle al of the nozzle 24 at a left end illustrated in FIG. 14 is used as a reference, an amount of liquid droplets is determined based on the incident angle al that is smallest among the four incident angles, for example. Therefore, for the nozzle 24 at a right end where the incident angle a4 that is largest, the setting of the amount of liquid droplets may be insufficient for mist suppression. That is, when an incident angle of any one of the nozzles 24 arranged at both ends is set as a reference, a deviation (an absolute value) of the incident angle from the incident angle of the other one increases. There is thus a possibility that it is difficult to sufficiently reduce the amount of liquid droplets for the other one, leading to generation of a mist.

[0070] When the incident angle a is different for each of the nozzles 24, it is preferable to determine the incident angle a0 based on a center m of an arrayed range H of the nozzles 24 as illustrated in FIG. 15 as a reference. As a result, a maximum deviation (an absolute value) between the incident angle a0 that serves as a reference and each of the incident angles al and a4 at both the ends is reduced. A mist is thus less likely to occur.

[0071] A position of the incident angle aO serving as a reference is not limited to the center m of the arrayed range H of the nozzles 24. Another positron may be used as a reference. For example, when the incident angle is constantly large at the position of the nozzle 24 at one end among the nozzles 24 at both the ends, the incident angle aO may be determined based on the position of the nozzle 24 at the one end. When only some of the nozzles 24 discharge liquid droplets, the incident angle aO may be determined based on the position of the center of the arrayed range of the nozzles 24 that actually discharge the liquid droplets.It is possible to appropriately change a method of how to determine the incident angle aO serving as a reference, in accordance with the shape of the target 200 or the arrangement of the nozzles 24, for example.

[0072] When the nozzles 24 are arranged in a zigzag manner in two rows, as illustrated in the example illustrated in FIG. 16, the center m of the arrayed range H of the nozzles 24 may be set as an intersection of diagonal lines of a parallelogram in which the nozzles 24 are arranged. The incident angle aO may then be determined based on the position of the intersection.

[0073] When the nozzles 24 are arranged in a zigzag manner, and when the discharge unit 1 is inclined with respect to the movement direction X, from the state illustrated in FIG. 17A to the state illustrated in FIG. 17B, for example, intervals VI and V2 between the nozzles 24 in the movement orthogonal direction Y do not become uniform. In this case, intervals in the movement orthogonal direction Y of the liquid droplets adjacent to each other, which are discharged from the nozzles 24, also do not become uniform. There may thus be deteriorated coating quality.

[0074] When the discharge unit 1 discharges liquid droplets in a state of being inclined with respect to the movement direction X, in the discharge unit 1 in which the nozzles 24 are arranged in a zigzag manner, it is preferable to discharge the liquid droplets from the nozzles 24 in one (one row) of an upper row and a lower row among the nozzles 24 arranged in the upper and lower two rows illustrated in FIGS. 17A and 17B.In this case, the incident angle aO serving as a reference is preferably determined based on the center of the arrayed range of the nozzles 24 from which the liquid droplets are actually discharged in the upper row and the lower row. When liquid droplets are discharged from only some of the nozzles 24 in the upper row or the lower row, a range from the nozzle 24 at one end to the nozzle 24 at another end of the some of the nozzles 24 that actually discharge the liquid droplets may be set as the arrayed range. The incident angle aO may then be determined based on the center of the arrayed range.

[0075] Even when liquid droplets are discharged from only the nozzles 24 in one of the upper and lower two rows, the incident angle aO serving as a reference may be determined based on thecenter m of the arrayed range H of the nozzles illustrated in FIG. 16. The incident angle aO serving as a reference may be determined based on the center of the arrayed range of the nozzles 24 in a row that is different from a row in which the liquid droplets are to be actually discharged.

[0076] When the incident angles a of some of the nozzles 24 are very large, there may be a case where it is difficult to effectively suppress a mist of liquid droplets discharged from the some of the nozzles 24, even when the incident angle aO is determined based on the center m of the arrayed range H of the nozzles 24. When the incident angles a of some of the nozzles 24 exceed a predetermined value that is set in advance, discharge of liquid droplets from the some of the nozzles 24 may be stopped. As a result, it is possible to prevent generation of a mist.

[0077] The predetermined value of the incident angle a serving as a criterion for determining whether or not to discharge liquid droplets may not be a fixed value that is set in advance. However, the value may be a value updated through machine learning.

[0078] Configuration of Machine LearningFIG. 18 is a block diagram of the control unit 5 having a machine learning function.

[0079] The control unit 5 illustrated in FIG. 18 includes a data accumulation unit 85, a learning unit 86, and an estimation unit 87.Functions of the data accumulation unit 85, the learning unit 86, and the estimation unit 87 may be implemented based on a machine learning program implemented on the control unit 5.

[0080] The data accumulation unit 85 accumulates data including at least the shape data of the target, the incident angle a, an amount of liquid droplets to be discharged, the inclination of the nozzle row, the landing intervals Px and Py, and a mist amount.

[0081] The learning unit 86 extracts the mist amount at a predetermined incident angle a based on the data accumulated in the data accumulation unit 85, and performs learning on a relationship between the incident angle a, the amount of liquid droplets to be discharged, and the inclination 0 of the nozzle row.

[0082] For example, the learning unit 86 may generate a learned model 88 having undergone learning on the relationship among the incident angle a, the amount of liquid droplets to be discharged, and the inclination 0 of the nozzle row using a data set in which the incident angle a, the amount of liquid droplets to be discharged, and the inclination 0 of the nozzle row, which are stored in the data accumulation unit 85, are associated with each other as teacher data. The learning unit may then cause the estimation unit 87 to hold the learned model.

[0083] There is no particular limitation in algorithm to be used in the learning unit 86. It is possible to apply deep learning based on a neutral network, an unsupervised learning model, a supervised learning model, and a reinforcement learning model, for example.

[0084] The estimation unit 87 estimates a predetermined value of the incident angle a serving as a criterion for determining whether or not to discharge liquid droplets based on learning that the learning unit 86 performs. When a value indicating an allowable mist generation amount is inputted, for example, the estimation unit 87 inputs the inputted value to the learned model 88, and estimates a predetermined value of the incident angle a, which is to be outputted from the learned model 88.

[0085] The control unit 5 controls an amount of liquid droplets to be discharged from the discharge unit 1 and the inclination p of the nozzle row based on the predetermined value of the incident angle a that the estimation unit 87 has estimated.

[0086] A liquid discharge apparatus according to the present embodiment, which includes the control unit 5 illustrated in FIG. 18, makes it possible to use a learned model through machine learning to adjust an amount of liquid droplets to be discharged from the discharge unit 1 and the inclination P of the nozzle row.

[0087] Example of Other Liquid discharge apparatusThe present embodiment is also applicable to liquid discharge apparatus having configurations described below.

[0088] FIG. 19 is an example of a coating device 800 that moves the target 200 instead of the discharge unit 1 to perform coating. In this case, the coating device 800 includes a robot arm 90 that holds and moves the target 200 and the discharge unit 1 fixed to a support table, for example. As the robot arm 90 moves the target 200, the discharge unit 1 discharges a liquid to the target 200. The liquid is thus applied to the target 200. The "movement" of the target 200 includes not only a case where the target 200 is moved in a linear or curvilinear manner, but also a case where the target 200 is rotated, its orientation with respect to the discharge unit 1 is changed, and the surface of the target 200 is moved.

[0089] When the incident angle a is large between the target 200 and the discharge unit 1, even in the coating device 800 having such a configuration as described above, a mist may be generated, leading to difficulties in favorably performing coating. When the incident angle a is large, it is preferable to reduce the amount of liquid droplets (reduce the landing area) and to reduce the landing interval of the liquid droplets, similar to each of the embodiments of the present embodiment. As a result, it is possible to suppress a mist and to favorably perform coating.

[0090] The moving mechanism included in the coating device according to the present embodiment is not limited to the moving mechanism that moves any one of the target 200 and the discharge unit 1 with respect to the other. The moving mechanism may be such a moving mechanism that relatively moves both the target 200 and the discharge unit 1. The moving mechanism is not limited to the robot arm, and may be, for example, a linear actuator that moves at least one of the target 200 and the discharge unit 1 in a linear manner in one direction, two directions orthogonal to each other, or three directions.

[0091] The discharge unit 1 according to the present embodiment is not limited to one including the nozzle plate 25 provided with the nozzles 24 as illustrated in FIG. 4. For example, the present embodiment is also applicable to a coating device 900 having a configuration in which the nozzles 24 protrude from the discharge unit 1 as illustrated in FIG. 20. In this case, the nozzle surface described above is represented by distal end surfaces 24a of the nozzles 24 or a main body outer surface 1 a of the discharge unit 1.

[0092] The present embodiment is also applicable to coating performed for purposes other than coloring and designing on a vehicle body of an automobile, for example. For example, a coating process for a vehicle body of an automobile includes undercoating aiming to secure adhesion of a coating film on and rust prevention for a base material of a vehicle body, intermediate coating aiming to secure impact resistance and durability, and top coating aiming to coloring and designing, for example. The coating device according to the present embodiment may be used for undercoating or intermediate coating, in addition to top coating. When there is, after the top coating, a coating process for applying a protective layer such as a clear layer aiming to lustering and protection of the coating film, the coating device according to the present embodiment may be used in the coating process for applying the protective layer. Furthermore, when a peelable protective layer for protecting the coating surface is coated on an automobile that is shipped or that is in a factory, it is also possible to use the coating device according to the present embodiment for coating the protective layer. The peelable protective layer may be any layer as long as it adheres to a coating surface of a vehicle body to make it possible to chemically or physically protect a coating portion from dust, metal powder, oil, salt, acid, and ultraviolet rays, and is preferably formed to include a material mainly containing an acrylic copolymer agent, for example.

[0093] The present embodiment is also applicable to a liquid discharge apparatus that discharges liquid droplets for purposes other than coating.For example, there is a marking device that discharges liquid droplets to a target to mark a specific portion.

[0094] The present embodiment is not limited to a liquid discharge apparatus that discharges liquid droplets to a three-dimensional structure such as a vehicle body or a building material, and is also applicable to a liquid discharge apparatus that discharges liquid droplets to a planar target such as a plate material or a sheet. Even in a case of a planar target, the incident angle of the liquid droplets with respect to the surface of the target may change when the surface is curved. Therefore, applying the present embodiment makes it possible to favorably attach a liquid to a target while suppressing a mist. Even when the surface of a target is a flat surface, it is preferable to apply the present embodiment in a case where it is necessary to discharge liquid droplets in a state where the nozzle surface is inclined with respect to the surface of the target. The "liquid discharge apparatus" according to the present embodiment may include a post-processing device, for example, in addition to a means relating to conveyance of a target and a pre-processing device.

[0095] To summarize the aspects of the present embodiment described above, the present embodiment includes at least the following aspects.

[0096] First AspectAccording to a first aspect, a liquid discharge apparatus includes: a discharge unit including nozzles that discharge liquid droplets to a target; and a moving mechanism that relatively moves at least one of the target and the discharge unit, in which an amount of one droplet of the liquid droplets and a landing interval of the liquid droplets are controlled in accordance with an incident angle of the liquid droplets at a landing position where the liquid droplets land on the target.

[0097] Second AspectAccording to a second aspect, in the liquid discharge apparatus of the first aspect, an inclination of an array direction of the nozzles with respect to a relative movement direction between the target and the discharge unit is changed to control the landing interval of the liquid droplets.

[0098] Third AspectAccording to a third aspect, in the liquid discharge apparatus of the first or second aspect, a relative movement speed between the target and the discharge unit is changed to control the landing interval of the liquid droplets.

[0099] Fourth AspectAccording to a fourth aspect, in the liquid discharge apparatus of any one of the first to third aspects, a time interval at which the liquid droplets are to be discharged is changed to control the landing interval of the liquid droplets.

[0100] Fifth AspectAccording to a fifth aspect, in the liquid discharge apparatus of any one of the first to fourth aspects, an opening time of each of the nozzles or an opening amount of each of the nozzles is changed to control the amount of the one droplet of the liquid droplets.

[0101] Sixth AspectAccording to a sixth aspect, in the liquid discharge apparatus of any one of the first to fifth aspects, discharge pressure for the liquid droplets is changed to control the amount of the one droplet of the liquid droplets.

[0102] Seventh AspectAccording to a seventh aspect, in the liquid discharge apparatus of any one of the first to sixth aspects, the amount of the one droplet of the liquid droplets and the landing interval of the liquid droplets are changed in two or more stages in accordance with the incident angle.

[0103] Eighth AspectAccording to an eighth aspect, in the liquid discharge apparatus of any one of the first to seventh aspects, the incident angle is determined based on a center of an arrayed range of the nozzles.

[0104] Ninth AspectAccording to a ninth aspect, in the liquid discharge apparatus of any one of the first to eighth aspects, when the incident angle at a position of one of some of the nozzles exceeds a predetermined value, discharging of the liquid droplets from the some of the nozzles is stopped.

[0105] Tenth AspectAccording to a tenth aspect, a liquid discharge apparatus includes: a discharge unit including a plurality of nozzles that discharges liquid droplets to a target; and a moving mechanism that relatively moves at least one of the target and the discharge unit, in which, when an incident angle of the liquid droplets at a landing position where the liquid droplets land on the target is a predetermined angle larger than 0°, the discharge unit discharges the liquid droplets to allow an interval between the liquid droplets that land adjacent to each other to be smaller than an interval in an array direction between the nozzles that discharge the liquid droplets, and to allow the liquid droplets that land adjacent to each other to partially overlap each other.

[0106] Eleventh AspectAccording to an eleventh aspect, a liquid discharge method for discharging liquid droplets from nozzles to a target, includes controlling an amount of one droplet of the liquid droplets and a landing interval of the liquid droplets in accordance with an incident angle of the liquiddroplets at a landing position where the liquid droplets land on the target to discharge the liquid droplets.The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and / or features of different illustrative embodiments may be combined with each other and / or substituted for each other within the scope of the present invention. Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.This patent application is based on and claims priority to Japanese Patent Application No. 2023-155831, filed on September 21, 2023, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.[Explanation of Reference Numerals]

[0107] 1 Discharge unit2 Coating robot11 First arm (moving mechanism)12 Second arm (moving mechanism)29 Liquid droplet90 Robot arm (moving mechanism)100 Coating device (liquid discharge apparatus)200 Target a Incident angleP Inclination of nozzle rowH Arrayed range of nozzles m CenterPx Landing interval in movement directionPy Landing interval in movement orthogonal directionS Landing areaX Movement directionY Movement orthogonal direction[Citation List][Patent Publication Reference]

[0108] [PTL 1] Japanese Patent No. 4792701

Claims

[CLAIMS]

1. A liquid discharge apparatus comprising: a discharge unit including nozzles from which liquid droplets are dischargeable to a target; a moving mechanism to relatively move at least one of the target and the discharge unit in a relative movement direction; and a control unit configured to control an amount of one droplet of the liquid droplets and a landing interval of the liquid droplets on the target in accordance with an incident angle of the one droplet of the liquid droplets with respect to a surface of the target at a landing position where the one droplet of the liquid droplets lands on the target.

2. The liquid discharge apparatus according to claim 1, wherein the discharge unit includes the nozzles arrayed in an array direction, and the control unit changes an inclination of the array direction of the nozzles with respect to the relative movement direction to control the landing interval of the liquid droplets.

3. The liquid discharge apparatus according to claim 1, wherein the control unit changes a relative movement speed between the target and the discharge unit to control the landing interval of the liquid droplets.

4. The liquid discharge apparatus according to claim 1, wherein the control unit changes a time interval at which the discharge unit discharges the liquid droplets to control the landing interval of the liquid droplets.

5. The liquid discharge apparatus according to claim 1, wherein the control unit changes an opening time of each of the nozzles or an opening amount of each of the nozzles to control the amount of the one droplet of the liquid droplets.

6. The liquid discharge apparatus according to claim 1, wherein the control unit changes discharge pressure of the discharge unit to discharge the liquid droplets to control the amount of the one droplet of the liquid droplets.

7. The liquid discharge apparatus according to claim 1, wherein the control unit controls the amount of the one droplet of the liquid droplets and the landing interval of the liquid droplets are changed in two or more stages in accordance with the incident angle.

8. The liquid discharge apparatus according to claim 1, wherein the control unit determines the incident angle based on a center of an arrayed range of the nozzles.

9. The liquid discharge apparatus according to claim 1, wherein the control unit cause the discharge unit to stop discharging the liquid droplets from a part of the nozzles when the incident angle at a position of the part of the nozzles exceeds a predetermined value.

10. A liquid discharge apparatus comprising: a discharge unit including nozzles to discharge liquid droplets to a target, the nozzles arrayed with an interval in an array direction; a moving mechanism to relatively move at least one of the target and the discharge unit; and a control unit configured to: cause the discharge unit to discharge the liquid droplets to the target; control a landing interval between the liquid droplets adjacent to each other on the target to be smaller than the interval of the nozzles in the array direction; and control the liquid droplets landing adjacent to each other to be partially overlapped with each other, when an incident angle of the liquid droplets, at a landing position where the liquid droplets land on the target, is a predetermined angle larger than 0°.

11. A liquid discharge method comprising: discharging liquid droplets from nozzles to a target; and controlling an amount of one droplet of the liquid droplets and a landing interval of the liquid droplets on the target in accordance with an incident angle of the liquid droplets of the liquid droplets with respect to a surface of the target at a landing position where the liquid droplets land on the target to discharge the liquid droplets to the target.

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