Liquid discharge apparatus and liquid discharge method

Abstract

A liquid discharge apparatus includes a liquid discharge head and a movement mechanism. The liquid discharge head has multiple nozzles including multiple first nozzles arrayed in a nozzle array direction to discharge a liquid in a form of individual liquid droplets from each of the multiple first nozzles onto a coating region of an object and a second nozzle adjacent to one end of the multiple first nozzles to discharge the liquid in a form of seamless liquid stream onto an edge of the coating region of the object. The movement mechanism moves at least one of the object or the liquid discharge head relative to another in a relative movement direction intersecting the nozzle array direction.

Description

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

[0001] Embodiments of the present disclosure relate to a liquid discharge apparatus and a liquid discharge method.[Background Art]

[0002] In the related art, a liquid discharge apparatus includes a liquid discharge head having multiple nozzles and discharges a liquid onto an object such as a component of a vehicle body (e.g., PTL 1).[Citation List][Patent Literature]

[0003] [PTL 1]Japanese Translation of PCT International Application Publication No. JP-T-2020-513315 [Summary of Invention] [Technical Problem]

[0004] However, with the technique of PTL 1, it is difficult to form a coating surface having a smooth edge in a scanning direction while preventing streaks in the coating surface.The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a liquid discharge apparatus and a liquid discharge method that form a coating surface having a smooth edge in the scanning direction while preventing streaks in a coating region.[Solution to Problem]

[0005] A liquid discharge apparatus includes a liquid discharge head and a movement mechanism. The liquid discharge head has multiple nozzles including multiple first nozzles arrayed in a nozzle array direction to discharge a liquid in a form of individual liquid droplets from each of the multiple first nozzles onto a coating region of an object and a second nozzle adjacent to one end of the multiple first nozzles to discharge the liquid in a form of seamless liquid stream onto an edge of the coating region of the object. The movement mechanism moves at least one of the object or the liquid discharge head relative to another in a relative movement direction intersecting the nozzle array direction.A liquid discharge method includes discharging a liquid in a form of individual liquid droplets from multiple first nozzles onto a coating region of an object to form multiple rows of the individual liquid droplets on the coating region of the object, discharging the liquid in a formof seamless liquid stream from a second nozzle onto an edge of the coating region of the object, and moving at least one of a liquid discharge head or the object relative to another. [Advantageous Effects of Invention]

[0006] According to one aspect of the present disclosure, a liquid discharge apparatus and a liquid discharge method can be provided that form a coating surface having a smooth edge in the scanning direction while preventing streaks in the coating region.[Brief Description of Drawings]

[0007] 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 is a diagram illustrating an overall configuration of a liquid discharge apparatus according to a first embodiment of the present disclosure.[FIG. 2]FIG. 2 is a diagram illustrating a configuration of a head of the liquid discharge apparatus of FIG. 1, according to the first embodiment.[FIG. 3]FIG. 3 is a cross-sectional view of the head of FIG. 2, according to the first embodiment.[FIG. 4]FIG. 4 is a diagram illustrating a configuration of a supply unit of the liquid discharge apparatus of FIG. 1, according to the first embodiment.[FIG. 5]FIG. 5 is a diagram illustrating a movement (scanning) of the head according to the first embodiment.[FIG. 6A]FIG. 6A is a block diagram illustrating a hardware configuration of a controller of the liquid discharge apparatus of FIG. 1, according to the first embodiment.[FIG. 6B]FIG. 6B is a block diagram illustrating a functional configuration of the liquid discharge apparatus of FIG. 1, according to the first embodiment.[FIGS. 7 A to 7D]FIGS. 7A to 7D are diagrams illustrating a state in which a liquid discharge apparatus according to a comparative example discharges liquid.[FIGS. 8 A and 8B]FIGS. 8 A and 8B are diagrams illustrating a state in which the liquid discharge apparatus of FIG. 1 discharges liquid, according to the first embodiment.[FIGS. 9 A and 9B]FIGS. 9A and 9B are diagrams each illustrating a waveform of a voltage applied to a piezoelectric element of the liquid discharge apparatus of FIG. 1, according to the first embodiment.[FIGS. 10A and 10B]FIGS. 10A and 10B are diagrams each illustrating another waveform of the voltage applied to the piezoelectric element of the liquid discharge apparatus of FIG. 1, according to the first embodiment.[FIG. 11]FIG. 11 is a diagram illustrating an arrangement relationship between nozzles and channels of the head according to the first embodiment.[FIG. 12]FIG. 12 is a diagram illustrating a discharge face of the head according to the first embodiment, and an application pattern of liquid discharged from the head.[FIG. 13]FIG. 13 is a diagram illustrating the discharge face of the head according to the first embodiment, and a first variation of the application pattern of liquid discharged from the head.[FIG. 14]FIG. 14 is a diagram illustrating the discharge face of the head according to the first embodiment, and a second variation of the application pattern of liquid discharged from the head.[FIG. 15]FIG. 15 is a diagram illustrating the discharge face of the head of according to the first embodiment, and a third variation of the application pattern of liquid discharged from the head.[FIG. 16]FIG. 16 is a diagram illustrating the discharge face of the head of according to the first embodiment, and a fourth variation of the application pattern of liquid discharged from the head.[FIG. 17]FIG. 17 is a diagram illustrating the discharge face of the head according to the first embodiment, and a fifth variation of the application pattern of liquid discharged from the head.[FIG. 18]FIG. 18 is a diagram illustrating the discharge face of the head according to the first embodiment, and a sixth variation of the application pattern of liquid discharged from the head.[FIG. 19]FIG. 19 is a diagram illustrating a first modification of the discharge face of the head according to the first embodiment.[FIG. 20]FIG. 20 is a diagram illustrating a second modification of the discharge face of the head according to the first embodiment.[FIG. 21]FIG. 21 is a diagram illustrating an overall configuration of a liquid discharge apparatus according to a second embodiment of the present disclosure.[FIGS. 22 A and 22B]FIGS. 22A and 22B are diagrams illustrating an overall configuration of a liquid discharge apparatus according to a third embodiment of the present disclosure.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]

[0008] 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] A liquid discharge apparatus and a liquid discharge method according to embodiments of the present disclosure will be described in detail with reference to the drawings. However, the following embodiments are merely examples of the liquid discharge apparatus and the liquid discharge method for embodying the technical idea of the present embodiment, and the present disclosure is not limited to the following embodiments. For example, the dimensions, materials, shapes of components described in the following embodiments, and relative arrangements thereof are not intended to limit the scope of the present disclosure thereto unless otherwise specified, and are merely examples for description. For example, the size and positional relationship of the components illustrated in the drawings may be exaggerated for clarity of description. In the following description, like names and like reference signs denote like or equivalent components, and a detailed description thereof may be omitted as appropriate.

[0010] First EmbodimentOverall Configuration of Liquid Discharge ApparatusFIG. 1 is a diagram illustrating an overall configuration of a liquid discharge apparatus 100 according to a first embodiment of the present disclosure. In FIG. 1, the liquid discharge apparatus 100 includes a liquid discharge unit 10 that discharges liquid to an object 200 and a controller 20 that controls the liquid discharge unit 10. The liquid discharge apparatus 100 includes four liquid discharge units 10 (10-1, 10-2, 10-3, and 10-4). The liquid discharge units 10 are arranged around the object 200 positioned at a coating position. Each of the liquid discharge units 10 includes a head 11 corresponding to a liquid discharge head, a detector 12, and a robot arm 13. The object 200 is, for example, a body of a vehicle, an aircraft, or a ship. The vehicle includes an automobile, a truck, and a train. In the example illustrated herein, the object 200 is a vehicle.

[0011] Each of the heads 11 (11-1, 11-2, 11-3, and 11-4) has a nozzle face in which multiple nozzles are formed, and are attached to the tip of the robot arm 13. The head 11 discharges liquid from the multiple nozzles. The robot arm 13 serves as a movement mechanism that moves the head 11 relative to the object 200. In the example illustrated in FIG. 1, the robot arm 13 moves the head 11 along the surface of the object 200, which may be referred to as a scanning of the head 11, to move the head 11 relative to the object 200. The head 11 applies the liquid discharged from the nozzles to the object 200 while being moved by the robot arm 13.

[0012] Each of the detectors 12 (12-1, 12-2, 12-3, and 12-4) is attached to the tip of the robot arm 13. The detector 12 outputs data of feature points regarding three-dimensional positions of three or more feature points in the object 200. The detector 12 may include a three-dimensional (3D) camera such as a stereo camera, a 3D sensor other than the stereo camera, or a laser displacement gauge. In the example illustrated in FIG. 1, the detector 12 includes a stereo camera. For example, the stereo camera measures the position and inclination in X and Y directions, detects a coating start position, and detects a coating target size. The stereo camera includes multiple cameras and acquires a distance image of the object 200 by a triangulation based on a parallax between images captured by the multiple cameras. The stereo camera can output the distance image to the controller 20 as the data of feature points. The detector 12 may include a laser displacement gauge. For example, the laser displacement gauge may measure a distance in a Z direction, detect the height of the roof of the object 200, and detect the curvature of the object 200.

[0013] Each of the robot arms 13 (13-1, 13-2, 13-3, and 13-4) includes links and joints. The robot arm 13 rotates or displaces the links and the joints to change the relative position and the relative inclination of the head 11 and the object 200. Thus, the nozzle face of the head 11 faces the object 200.

[0014] The controller 20 drives the robot arms 13 holding the respective four heads 11 based on shape data of the predetermined object 200 and the data of feature points regarding the three- dimensional positions of the three or more feature points output from the corresponding four detectors 12. The liquid discharge apparatus 100 applies the liquid discharged from the four heads 11 to the object 200 to coat the object 200 with the liquid.

[0015] The liquid discharge apparatus 100 may include a supply unit and a maintenance unit in addition to the configuration illustrated in FIG. 1. The supply unit supplies liquid to be discharged to the object 200 to each of the four heads 11. The maintenance unit removes thickened liquid and foreign substances adhering to the nozzle face of the head 11 or inside the head 11. With such a configuration, abnormal discharge such as non-discharge, oblique discharge, and discharge speed fluctuation in the head 11 can be prevented, and the discharge state of the head 11 can be maintained in a normal condition.

[0016] In the liquid discharge apparatus 100, the object 200 is conveyed to the coating position, and the head 11 is moved by the robot arm 13 relative to the object 200 not in motion to coat the object 200. The object 200 that has been coated is conveyed from the coating position to the outside, and the next object 200 is conveyed to the coating position.

[0017] Configuration of Head of Liquid Discharge ApparatusAn example of the configuration of the head 11 of the liquid discharge apparatus 100 will be described below with reference to FIGS. 2 and 3. FIG. 2 is a diagram illustrating the configuration of the head 11 according to the first embodiment. FIG. 3 is a cross-sectional view of the head 11 according to the first embodiment, taken along plane S 1 in FIG. 2. In FIGS. 2 and 3, the head 11 includes a supply port 111, a collection port 112, and discharge modules 340.

[0018] A pressurized liquid is supplied from the outside to the discharge modules 340 through the supply port 111. The liquid, which has not been discharged from a nozzle 311 when a valve of the nozzle 311 is opened, is drained to the outside through the collection port 112. The nozzle 311 is described in detail later.

[0019] The discharge module 340 includes a housing 110, a nozzle plate 321 having the nozzle 311, a channel 322 of the liquid, a valve 310, and a piezoelectric element 324.

[0020] The nozzle plate 321 is bonded to the housing 110. The liquid supplied from the supply port 111 is discharged from the nozzle 311 of the nozzle plate 321. The channel 322 (i.e., acommon channel) is shared with the multiple discharge modules 340 (eight discharge modules in FIG. 2) in the housing 110.

[0021] The valve 310 is an example of a needle-shaped valve body. The valve 310 is driven by the piezoelectric element 324 and reciprocally moves in a liquid discharge direction in the housing 110 to open and close the nozzle 311. In the head 11 according to the present embodiment, the pressurized liquid is supplied from the supply port 111 through the channel 322 with a valve of the collection port 112 closed. When the valve 310 closes the nozzle 311, the liquid is not discharged from the nozzle 311. When the piezoelectric element 324 is driven to move the valve 310 upward, the valve 310 opens the nozzle 311, and the liquid is discharged from the nozzle 311.

[0022] Configuration of Supply Unit of Liquid Discharge ApparatusFIG. 4 is a diagram illustrating a configuration of a supply unit 14 of the liquid discharge apparatus 100. In FIG. 4, the supply unit 14 includes liquid tanks 330 (330-1, 330-2, 330-3, and 330-4) as sealed containers that store liquid 325 to be discharged from the head 11. The liquid tanks 330 and inlets (i.e., the supply ports 111) of the heads 11 are connected via tubes 333, respectively. Thus, the liquid 325 flows from the liquid tanks 330 to the heads 11 through the tubes 333.

[0023] The liquid tanks 330 are connected to a compressor 230 via a pipe 331 including air regulators 332. The compressor 230 supplies pressurized air to the liquid tanks 330. Accordingly, the pressurized liquid 325 is supplied to the inlet of the head 11, and the liquid discharge apparatus 100 discharges the liquid 325 from the nozzles 311 of the head 11.

[0024] In the present embodiment, the liquid tanks 330 are provided for the heads 11, respectively. Alternatively, the liquid 325 may be supplied from one liquid tank 330 to all the heads 11.

[0025] Example of Movement of Head of Liquid Discharge ApparatusFIG. 5 is a diagram illustrating an example of movement (scanning) of the head 11 of the liquid discharge apparatus 100. In FIG. 5, an example of the object 200 is an automobile, and the coating areas 211 (211-1, 211-2, 211-3, and 211-4) are the roof of the automobile. The four robot arms 13 illustrated in FIG. 1 move the corresponding heads 11 relative to the object 200 to coat the object 200 with liquid in the respective coating areas 211. The coating areas 211 and movement paths T1 (Tl-1, Tl-2, Tl-3, and Tl-4) are different for the four heads 11, respectively. The movement path T1 may be referred to as a scanning route.

[0026] The robot arm 13-1 moves the head 11-1 relative to the object 200 to coat the object 200 with the liquid in the coating area 211-1. The head 11-1 is moved relative to the object 200 along the movement path Tl-1.

[0027] The robot arm 13-2 moves the head 11-2 relative to the object 200 to coat the object 200 with the liquid in the coating area 211-2. The head 11-2 is moved relative to the object 200 along the movement path Tl-2.

[0028] The robot arm 13-3 moves the head 11-3 relative to the object 200 to coat the object 200 with the liquid in the coating area 211-3. The head 11-3 is moved relative to the object 200 along the movement path Tl-3.

[0029] The robot arm 13-4 moves the head 11-4 relative to the object 200 to coat the object 200 with the liquid in the coating area 211-4. The head 11-4 is moved relative to the object 200 along the movement path Tl-4.

[0030] Configuration of Hardware of Liquid Discharge ApparatusFIG. 6A is a block diagram illustrating an example of a coating system 10000, which will be described as a functional configuration of the liquid discharge apparatus 100. FIG. 6B is a block diagram illustrating a software configuration of a controller 901 illustrated in FIG. 6A. In FIG. 6A, the coating system 10000 includes the controller 901, a head control device 902, a robot control device 904, coating robots 1000A and 1000B, and a personal computer (PC) 903. In FIG. 6 A, the controller 901 includes a central processing unit (CPU) 9001, a readonly memory (ROM) 9002, a random-access memory (RAM) 9003, and an interface (I / F) 9004. The controller 901, the head control device 902, and the robot control device 904 in FIGS. 6 A and 6B correspond to the controller 20 in FIG. 1. A head unit 103 in FIG. 6 A corresponds to the liquid discharge unit 10 in FIG. 1. Although, the four liquid discharge units 10 are illustrated in FIG. 1, two head units 103 are illustrated in FIG. 6A for simplicity. In the following description, the two coating robots 1000A and 1000B are collectively referred to as “coating robots 1000,” each of which is referred to as a coating robot 1000 unless distinguished.The PC 903 includes a raster image processor (RIP) unit 9031 that performs image processing in accordance with a color profile and user settings, and a rendering unit 9032 that decomposes data of a coating portion of the object 200 (e.g., a body of an automobile) into coating data (image data) for each scanning (e.g., each movement of the head 11 in the main scanning direction).

[0031] An input device 9033 is connected to the PC 903, for example, to set image data and coordinate data of the coating portion of the object 200, to select a coating mode, to set acoating area (e.g., the coating start position and coating end position), and to input an instruction for coating. The input device 9033 includes, for example, a keyboard, a mouse, and a touch panel to receive input from a user. The PC 903 acquires position data from a position measuring device 400 of the coating robot 1000 and generates a coating route of the coating robot 1000.

[0032] The controller 901 is connected to the PC 903. The CPU 9001 is an arithmetic device that loads a program or data stored in, for example, the ROM 9002 into the RAM 9003 and executes processing to implement functions of the coating robot 1000. The CPU 9001 has a function of a system control unit 9011 that controls the overall operation of the coating system 10000 using the image data of the coating portion and commands received from the PC 903. The CPU 9001 has a function of a memory control unit 9013 that controls a data storage unit 9012, a function of a discharge cycle signal generation unit 9014 that generates a discharge cycle signal of liquid, and a function of a synchronization control unit 9015 that synchronizes the movements of the coating robots 1000A and 1000B with an ink discharge operation. The CPU 9001 that functions as the memory control unit 9013 executes a program recorded in advance as stored data to implement the functions as the controller 901.

[0033] The ROM 9002 is a nonvolatile memory that retains the program or data even after the power is turned off. The RAM 9003 is a volatile memory that is used as, for example, a work area for the CPU 9001. The ROM 9002 and the RAM 9003 have a function of the data storage unit 9012 that stores, for example, the image data received from the PC 903 and data of the coating area (coating target size). For example, a hard disk drive (HDD) or a solid-state drive (SSD) may be used as a configuration having the function of the data storage unit 9012.

[0034] The PF 9004 is an interface for inputting and outputting, for example, characters, numerals, and various instructions to and from various external devices. The PF 9004 is an interface that allows the controller 901 to communicate with an external device such as the PC 903.

[0035] The coating robot 1000 is, for example, a multi-articulated robot as illustrated in FIG. 1. The coating robot 1000 includes a first joint, a second joint, and a third joint provided with an encoder sensor 109.

[0036] The encoder sensor 109 optically detects slits of encoders of, for example, the first joint, the second joint, and the third joint. Then, the positions of a first arm and a second arm of the robot arm 13, and the head unit 103 are detected from the rotation amounts of the first arm, the second arm, and the head unit 103 to acquire three-dimensional position data of the head unit 103. The discharge cycle signal generation unit 9014 generates the discharge cyclesignal of liquid based on an output signal of the encoder sensor 109 and information indicating the resolution of the image data received from the PC 903.

[0037] The synchronization control unit 9015 synchronizes the movements of the coating robots 1000A and 1000B with the ink discharge operation based on the image data and the instruction for coating received from the PC 903.

[0038] The head control device 902 receives the discharge cycle signal from the discharge cycle signal generation unit 9014 of the controller 901 and controls the ink discharge operation in the head 11 based on the discharge cycle signal. The robot control device 904 receives a synchronization control signal from the synchronization control unit 9015 of the controller 901 and controls the driving of a robot driver 72 based on the synchronization control signal. The first arm, the second arm, and the head unit 103 of the coating robot 1000 are moved to desired positions by controlling the driving of the robot driver 72.

[0039] The coating robot 1000 includes the head unit 103, the encoder sensor 109, and the robot driver 72. The head unit 103 includes the head 11 and the detector 12. The head 11 discharges liquid in response to a drive signal from the head control device 902. The detector 12 transmits a detection result of the object 200 to the PC 903.

[0040] The robot driver 72 moves the first arm, the second arm, and the head unit 103 of the coating robot 1000 to desired positions in response to a drive signal from the robot control device 904. Although the head control device 902 and the robot control device 904 according to the present embodiment are shared by the two coating robots 1000A and 1000B, the head control device 902 and the robot control device 904 may be provided for each coating robot. The RIP unit 9031 and the rendering unit 9032 are installed in the PC 903 in the present embodiment, but may be installed in the system control unit 9011 of the controller 901 in another embodiment.

[0041] Comparison of Liquid Discharge Apparatuses between Comparative Example and Present EmbodimentA liquid discharge apparatus according to a comparative example and the liquid discharge apparatus 100 according to the present embodiment are compared with each other with reference to FIGS. 7A to 8B. FIGS. 7A to 7D are diagrams illustrating a state in which a liquid discharge apparatus according to the comparative example discharges liquid. FIG. 7 A illustrates a state in which the liquid discharge apparatus intermittently discharges the liquid, and FIG. 7B illustrates a shape of a coating surface when the liquid is intermittently applied. FIG. 7C illustrates a state in which the liquid discharge apparatus continuously discharges the liquid, and FIG. 7D illustrates a shape of the coating surface when the liquid is continuouslyapplied. FIGS. 8 A and 8B are diagrams illustrating a state in which the liquid discharge apparatus 100 according to the present embodiment discharges liquid. FIG. 8A illustrates a state in which the liquid discharge apparatus 100 discharges the liquid according to the present embodiment, and FIG. 8B illustrates a shape of the coating surface when the liquid is applied by the configuration according to the present embodiment.

[0042] The phrase “intermittently discharging liquid” means that a head cyclically repeats a state of discharging liquid and a state of not discharging liquid while moving in the main scanning direction (X-axis direction). A specific example of intermittently discharging liquid is discharging liquid droplets. On the other hand, the phrase “continuously discharging liquid” means that the head continues discharging liquid while moving in the main scanning direction. In other words, the phrase “continuously discharging liquid” means that the head seamlessly (without interruption) discharges liquid (in other words, discharges liquid in the form of a continuous liquid stream or seamless liquid stream) in the main scanning direction of the head while moving in the main scanning direction. In the following description, the liquid intermittently discharged may be referred to as “liquid droplets,” and the liquid continuously discharged may be referred to as a “liquid thread.”

[0043] As illustrated in FIGS. 7A and 7B, when the liquid discharge apparatus discharges liquid droplets, the liquid droplets land on an object to be coated and spread in a circular shape on the object to form dots. The formed dots overlap with surrounding dots so as to fill gaps therebetween to form the coating surface. At this time, since the formed dots are circular, an edge of the coating surface is formed in a waved shape along the shape of the dots. Accordingly, the liquid discharge apparatus that discharges liquid droplets to form a coating surface does not form the smooth edge of the coating surface in the movement (scanning) direction of the head.

[0044] As illustrated in FIGS. 7C and 7D, when the liquid discharge apparatus discharges the liquid thread, the liquid thread landed on the object to be coated does not form a dot but forms a line extending in the main scanning direction (X-axis direction) of the liquid discharge apparatus. Accordingly, the edge of the coating surface in the sub-scanning direction (Y-axis direction) has a smooth shape extending in the main scanning direction (X-axis direction). However, the formed line spreads narrower than the dots in a direction (Y-axis direction: also referred to as the sub-scanning direction) orthogonal to the main scanning direction. As a result, lines adjacent to each other in the sub- scanning direction may not form the coating surface, and a streak extending in the main scanning direction may be generated between the lines.

[0045] By contrast, the liquid discharge apparatus 100 according to the present embodiment can discharge liquid droplets and a liquid thread in parallel while the head moves in the mainscanning direction (i.e., in one scanning or one movement) as illustrated in FIGS. 8A and 8B. Thus, the edge of the coating surface extending in the main scanning direction can be formed by the liquid thread. The head discharges the liquid droplets and the liquid thread so that the line formed by the liquid thread overlaps the waved shape of the edge of the shape of the dots. Accordingly, the liquid discharge apparatus 100 can form the coating surface having the smooth edge extending in the scanning direction of the head while preventing streaks in a coating region by one scanning (movement).

[0046] Method of Discharging Liquid Droplet and Liquid ThreadA method of discharging liquid droplets and a liquid thread by the liquid discharge apparatus 100 according to the present embodiment will be described below with reference to FIGS. 9 A and 9B. FIGS. 9A and 9B are diagrams each illustrating a waveform of a voltage applied to the piezoelectric element 324. FIG. 9A illustrates a waveform when the liquid discharge apparatus 100 intermittently discharges liquid (also referred to as the liquid droplets), and FIG. 9B illustrates a waveform when the liquid discharge apparatus 100 continuously discharges liquid (also referred to as the liquid thread).

[0047] As illustrated in FIG. 9A, when the liquid droplets are discharged, for example, a voltage is applied in a square wave shape, and thus the valve of the nozzle 311 is repeatedly opened and closed. On the other hand, as illustrated in FIG. 9B, when the liquid thread is discharged, for example, a constant voltage is applied, and thus the valve of the nozzle 311 is continuously opened without repeating the opened state and the closed state. As described above, the voltage applied to the piezoelectric element 324 controls the opening and closing of the valve of the nozzle 311 to switch between the discharge of the liquid droplets and the discharge of the liquid thread.

[0048] At this time, when the maximum values of the voltages applied for discharging the liquid droplets and for discharging the liquid thread are the same, the amount of liquid per unit time discharged from the nozzle for discharging the liquid droplets, which includes the valve in the closed state, is smaller than that discharged from the nozzle for discharging the liquid thread. For this reason, unevenness in an application amount of liquid may be generated between the region into which the liquid droplets are applied and the region into which the liquid thread is applied. Accordingly, to apply liquid evenly regardless of the liquid discharge method, the applied voltages are preferably adjusted for discharging liquid droplets and for discharging a liquid thread so that the amounts of liquid discharged per unit time for the liquid droplets and for the liquid thread are equal to each other.

[0049] Examples of the applied voltage for adjusting the amount of liquid discharged per unit time will be described below with reference to FIGS. 10A and 10B. FIGS. 10A and 10B arediagrams each illustrating a waveform of a voltage applied to the piezoelectric element 324. The discharge amounts of the liquid droplets and the liquid thread per unit time are adjusted as illustrated in FIGS. 10A and 10B. FIG. 10A illustrates a waveform when the liquid discharge apparatus 100 intermittently discharges liquid, and FIG. 10B illustrates a waveform when the liquid discharge apparatus 100 continuously discharges liquid. In the following description, the nozzle for discharging the liquid droplets and the nozzle for discharging the liquid thread have the same configuration such as the diameter of hole and the structure of channel. However, the nozzle for discharging the liquid droplets and the nozzle for discharging the liquid thread may have different configurations such as the diameter of hole and the structure of channel. Even when the diameter of hole and the structure of channel are different, the discharge amounts of the liquid droplets and the liquid thread per unit time can be adjusted by adjusting the applied voltages.

[0050] As illustrated in FIG. 10A, the voltage applied for discharging the liquid droplets is adjusted to be higher than the voltage before adjustment (broken line) applied for discharging the liquid thread. The adjusted voltage increases the discharge amount of liquid (i.e., the liquid droplets) per unit time when the valve of the nozzle 311 is opened. As illustrated in FIG. 10B, the voltage applied for discharging the liquid thread is adjusted to be lower than the voltage before adjustment (broken line) applied for discharging the liquid droplets. The adjusted voltage decreases the discharge amount of liquid (i.e., the liquid thread) per unit time. As described above, the discharge amount of liquid discharged in the form of the liquid droplets is increased, and the discharge amount of liquid discharged in the form of the liquid thread is decreased. As a result, the discharge amounts of the liquid droplets and the liquid thread per unit time can be equalized. The equalized discharge amounts of the liquid droplets and the liquid thread per unit time can perform uniform coating with the liquid.

[0051] The applied voltage may be adjusted using a reference voltage determined for each nozzle 311. For example, a predetermined discharge amount of liquid is discharged by the reference voltage, corresponding to a standard value calculated from the film thickness of coating and the covering power of the liquid against a foundation. When the applied voltage is adjusted using the reference voltage, the voltage applied for discharging the liquid droplets is set to be higher than the reference voltage, and the voltage applied for discharging the liquid thread is set to be lower than the reference voltage. However, when the applied voltage is adjusted using the reference voltage, either the voltage applied for discharging the liquid droplets or the voltage applied for discharging the liquid thread may be adjusted.

[0052] Relationship between Channel and NozzleAn arrangement of the nozzles 311 and the channel 322 of the head 11 according to the present embodiment will be described below with reference to FIG. 11. FIG. 11 is a diagramof a discharge face of the head 11, illustrating an example of an arrangement relationship between the nozzles 311 and the channel 322. In FIG. 3, the head 11 has eight nozzles 311 arranged in a row. In FIG. 11, for the sake of simplicity, the head 11 has two nozzles 311 and three nozzles 311 arranged in parallel.

[0053] The head 11 has the nozzles 311 arranged in a staggered manner and the channel 322 for supplying liquid to each of the nozzles 311. The channel 322 branches into two through which the liquid is supplied from the supply port 111 to the nozzles 311 on the left and right sides in FIG. 11, respectively. The two branched channels 322 join into one, through which the liquid that has not discharged from the nozzles 311 on the left and right sides flows to the collection port 112, on the downstream side.

[0054] Example of Application of LiquidExamples of an application of the liquid discharged by the head 11 according to the present embodiment will be described below with reference to FIGS. 12 to 18. FIG. 12 is a diagram illustrating the discharge face of the head 11 and an example of an application pattern of the liquid discharged from the head 11. In FIGS. 12 to 18, the head 11 has the two nozzles 311 and the three nozzles 311 arrayed in two parallel rows (i.e., in a nozzle array direction) as illustrated in FIG. 11. Blank arrows illustrated in FIGS. 12 to 18 indicate examples of the relative movement of the head 11 and the object 200. In FIGS. 12 to 18, the head 11 moves relative to the object 200 in a scanning direction (i.e., a relative movement direction intersecting the nozzle array direction) indicated by the blank arrows. In other examples of the relative movement of the head 11 and the object 200, the object 200 may move relative to the head 11 in a direction opposite to the scanning direction indicated by the blank arrows. An upper (lower) direction described below indicates +Y (-Y) direction illustrated in each of FIGS. 12 to 18, and a right (left) direction described below indicates +X (-X) direction illustrated in each of FIGS. 12 to 18. The rotation in the clockwise (counterclockwise) direction indicates that the head 11 rotates in the clockwise (counterclockwise) direction around the Z axis as viewed in the Z direction. These directions do not limit the scanning direction of the head 11 and the arrangement of the nozzles 311, and may be directions described below, the reversed directions thereof, or the rotated directions thereof.

[0055] In FIG. 12, the head 11 applies the liquid thread to the edge of the coating region of the object 200 in the sub- scanning direction at one end (lower end) in the vertical direction. The vertical direction in FIG. 12 is the sub-scanning direction intersecting the main scanning direction. The head 11 discharges the liquid thread from a nozzle 31 IL (i.e., an example of a second nozzle) and discharges the liquid droplets from the other nozzles 311 (i.e., an example of a first nozzle) while moving in the main scanning direction. At this time, the nozzle 31 IL is positioned at the end (lower end) in the vertical direction in FIG. 12 among the nozzles fromwhich liquid is discharged. In other words, the nozzle 31 IL is disposed at the end of the head 11 in the sub-scanning direction among the nozzles, from which liquid is discharged, i.e., in the direction (nozzle array direction) intersecting the direction of the relative movement of the head 11. The nozzles 311 and the nozzle 31 IL adjacent to each other are disposed such that intervals LI, L2, L3, and L4 between the centers thereof in the longitudinal direction of the head 11 are equal to each other.

[0056] Liquid droplets 510 discharged from the nozzles 311 land on the object 200 and spread on the surface of the object 200 so that adjacent liquid droplets 510 overlap each other. At this time, the lower end of the region coated by the nozzle 311 is formed in a waved shape along the shape of the liquid droplets 510 which are disposed adjacent to each other in the main scanning direction and spread so as to overlap each other. However, since a liquid thread 501 is applied from the nozzle 31 IL onto the object 200 so as to overlap the waved shape of the region coated with the liquid droplets, the lower end (edge of the coating region) can be formed in a smooth shape extending in the main scanning direction of the head 11. In the present embodiment, the head 11 moves in a straight line as an example, i.e., the scanning of the head 11 is straight. Alternatively, the head 11 may move in a curved line, i.e., the scanning of the head 11 may be partly curved. As illustrated in FIG. 13, the inclined head 11 may discharge the liquid droplets 510 and the liquid thread 501 while moving in the main scanning direction. In this case, since the interval between the adjacent liquid droplets 510 and the interval between the liquid droplet 510 and the liquid thread 501 in the same row are narrowed in the direction orthogonal to the main scanning direction, the liquid can be applied more densely.

[0057] In FIG. 14, the head 11 applies the liquid threads to the edges of the coating region of the object 200 in the sub-scanning direction at both ends in the vertical direction (also referred to as the sub- scanning direction) intersecting the main scanning direction. The head 11 discharges the liquid threads 501 and 502 from the nozzles 31 IL positioned at both ends in the vertical direction and discharges the liquid droplet 510 from the other nozzles 311 while moving in the scanning direction. The liquid threads 501 and 502 discharged from the nozzles 31 IL positioned at both ends in the vertical direction overlap the waved shapes formed at the upper and lower ends of the region coated by the nozzles 311. Thus, both ends in the vertical direction (edge portions of the coating region) can be formed in the smooth shape extending in the main scanning direction of the head 11.

[0058] In FIG. 15, the width of the coating region of the object 200 in the sub-scanning direction is narrower than the width which can be coated by one movement (scanning) of the head 11 in the sub-scanning direction. The head 11 discharges the liquid thread 501 from the nozzle 31 IL positioned at the lower end in the vertical direction among the nozzles from whichliquid is being discharged and discharges the liquid droplets 510 from other nozzles 311 while moving in the main scanning direction. At this time, a nozzle 31 In positioned below the nozzle 31 IL in the vertical direction is set to discharge neither the liquid droplets 510 nor the liquid thread 501 (i.e., a non-discharge nozzle). The liquid thread 501 discharged from the nozzle 31 IL overlaps the waved shape formed at the lower end of the region coated by the nozzle 311. Thus, the lower end in the vertical direction (edge of the coating region) can be formed in the smooth shape extending in the main scanning direction of the head 11.

[0059] As illustrated in FIG. 16, in the vertical direction intersecting the main scanning direction of the head 11, even when the width of the coating region of the object 200 in the sub-scanning direction is narrower than the width which can be coated by one movement (scanning) of the head 11 in the sub-scanning direction, the nozzles from which liquid is being discharged at both ends in the vertical direction can be the nozzles 31 IL. Thus, similarly to the second variation described with reference to FIG. 14, both ends in the vertical direction (edge portions of the coating region) can be formed in the smooth shape extending in the main scanning direction of the head 11.

[0060] In FIG. 17, in the vertical direction intersecting the main scanning direction of the head 11, the width of the coating region of the object 200 in the sub-scanning direction is wider than the width which can be coated by one movement (scanning) of the head 11 in the subscanning direction. As illustrated in FIG. 17, the head 11 discharges the liquid droplets 510 from all the nozzles 311 while moving in the main scanning direction from left to right. In other words, the controller 20 sets all of the multiple nozzles to the nozzles 311. When one line of the coating region in the main scanning direction has been coated, the head 11 moves below the coated one line in parallel with the sub-scanning direction while keeping the posture thereof. At this time, the head 11 does not discharge the liquid droplets 510 and the liquid thread 501.

[0061] After the head 11 moves downward, the head 11 moves from right to left. At this time, the controller 20 sets (converts) the nozzle 311 at the position facing the edge (lower end in FIG. 17) of the coating region to the nozzle 31 IL for discharging the liquid thread 501 when the head 11 moves from right to left (this scanning direction of the head 11 is also referred to as the main scanning direction). At the same time, the controller 20 sets the other nozzles to the nozzles 311 for discharging the liquid droplets 510. Accordingly, even when the width of the coating region of the object 200 in the sub- scanning direction is wider than the width which can be coated by one movement (scanning) of the head 11, the coating region having the smooth edge extending in the main scanning direction can be formed while preventing streaks in the coating region.

[0062] In FIG. 18, the head 11 discharges the liquid threads 501 onto two edges of the coating region intersecting each other.

[0063] As illustrated in FIG. 18, the head 11 discharges the liquid droplets 510 from all the nozzles 311 while moving in the main scanning direction (X-axis direction) from left to right. When one line of the coating region in the main scanning direction has been coated, the head 11 is rotated in the counterclockwise direction with the discharge face of the head 11 facing the object 200.

[0064] After the head 11 is rotated, the head 11 discharges the liquid while moving from the upper side to the lower side in FIG. 18 (in the Y-axis direction, and in this example, the Y-axis direction is also referred to as the main scanning direction). At this time, when the head 11 moves below the coated line, the controller 20 sets two nozzles on the left side of the head 11 (also referred to as two nozzles in the X-axis direction) to the nozzles 311 for discharging the liquid droplets 510. At the same time, the controller 20 sets the third nozzle from the left in FIG. 18 in the X-axis direction to the nozzle 31 IL for continuously discharging the liquid thread 501, and sets the remaining nozzles 311 to non-discharge nozzles. When the setting of the liquid discharge type of each nozzle is completed, the head 11 moves from the upper side to the lower side in FIG. 18 to discharge the liquid. After the head 11 moves below the coated line, the head 11 stops moving and discharging the liquid, and the head 11 is rotated in the clockwise direction.

[0065] After the head 11 is rotated, the head 11 discharges the liquid while moving from right to left in FIG. 18 (in the X-axis direction). At this time, the controller 20 sets the nozzle 311 corresponding to the edge (lower end in FIG. 18) of the coating region to the nozzle 31 IL for discharging the liquid thread 501 when the head 11 moves from right to left in FIG. 18. At the same time, the controller 20 sets the other nozzles to the nozzles 311 for discharging the liquid droplets 510.Accordingly, even when the width of the coating region of the object 200 is wider than the width which can be coated by one movement (scanning) of the head 11, the coating region having two smooth edges extending in the scanning directions can be formed while preventing streaks in the coating region.

[0066] According to the above-described embodiment, the liquid droplets can be applied inside the coating region without a gap, and the liquid thread can be applied to the edge of the coating region to form a smooth edge extending in the scanning direction. Thus, for example, when the roof of the automobile illustrated in FIG. 5 is an object to be coated, the four heads 11 can coat the inside of the broken lines surrounding the coating areas 211-1, 211-2, 211-3, and 211-4 with liquid (liquid droplets) without a gap and can linearly coat the broken lines (edges)with liquid (liquid thread), respectively. However, in a portion of the coating area adjacent to the coating area of another head 11 among the broken lines, the liquid droplets may be discharged and applied onto the object without a gap.

[0067] Example of Nozzle ArrangementA modification of the arrangement of the nozzles 311 in the head 11 will be described below with reference to FIGS. 19 and 20. FIG. 19 is a diagram illustrating a first modification of the discharge face of the head 11. FIG. 20 is a diagram illustrating a second modification of the discharge face of the head 11.

[0068] In the first modification illustrated in FIG. 19, a head unit 103a includes multiple heads described in the first embodiment. In FIG. 19, the head unit 103a includes two heads 11 (11A and 1 IB) described with reference to FIGS. 11 to 18. The head 11A and the head 1 IB are shifted by half of a nozzle interval (also referred to as a half pitch) in the nozzle array direction (the vertical direction in FIG. 19 or the sub-scanning direction intersecting the main scanning direction). In other words, the multiple nozzles of the head 11 A are positioned between the multiple nozzles of the head 1 IB in the nozzle array direction. In this case, the nozzle interval is, for example, a center-to-center distance between nozzles adjacent to each other in the nozzle array direction. The head unit 103a illustrated in the present modification can move and apply the liquid to the coating region in the same manner as in the first embodiment described above.

[0069] In FIG. 19, a channel branches from the liquid tank 330 to the head 11 A and the head 1 IB to supply liquid to the head 11A and the head 1 IB, but the channel for supplying liquid is not limited thereto. For example, the liquid may be supplied from the liquid tanks 330 to the respective heads separately.

[0070] The second modification illustrated in FIG. 20 is different from the first embodiment in that a head unit 103b includes different heads 11D and HE having the nozzles 311 for discharging the liquid droplets and the nozzles 31 IE for discharging the liquid thread, respectively. In the head 11 described in the first embodiment, the nozzles are switched between the nozzles 311 for discharging the liquid droplets and the nozzles 31 IL for discharging the liquid thread. By contrast, the head unit 103b described in the present modification includes the head 1 ID having the nozzles 311 for discharging only the liquid droplets and the head 1 IE having the nozzles 31 IL for discharging only the liquid thread.

[0071] To coat the coating region with the smooth edge, extending the main scanning direction, in the sub-scanning direction by one movement (scanning) of the head 11 as in the first embodiment, the head 1 ID and the head 1 IE are preferably arranged in the main scanningdirection and the nozzles are arrayed in the vertical direction (also referred to as the subscanning direction) intersecting the main scanning direction. However, since the interval between adjacent nozzles in the sub- scanning direction is small, it is structurally difficult to arrange the head 1 ID and the head 1 IE so that the discharged liquid droplets and liquid thread overlap.

[0072] For this reason, in the present modification, the head 1 ID and the head 1 IE are arranged side by side in the main scanning direction. The nozzle 31 IL of the head 1 IE and the nozzle 311 on the right side of the head 1 ID are arranged in the main scanning direction. Accordingly, the liquid thread discharged from the nozzle 31 IL of the head 1 IE overlaps the liquid droplets discharged from the nozzle 311 at the end of the head 1 ID in the vertical direction. Thus, as in the first embodiment, the edge of the coating region can be formed in the smooth shape extending in the scanning direction. The head 1 IE does not discharge the liquid from all the nozzles 31 IL, but discharges the liquid (liquid thread) only from the nozzle 31 IL disposed at a position facing the edge of the coating region.

[0073] Second EmbodimentA liquid discharge apparatus according to a second embodiment of the present disclosure will be described below with reference to FIG. 21. FIG. 21 is a diagram illustrating an overall configuration of a liquid discharge apparatus 150 according to the second embodiment. The liquid discharge apparatus 150 is different from the first embodiment in that the head 11 is fixed and the object 200 is moved to be coated.

[0074] The liquid discharge apparatus 150 illustrated in FIG. 21 holds the object 200 by the robot arm 13 and moves the object 200 to the vicinity of the fixed head 11. Then, the robot arm 13 moves the object 200 to a liquid discharge position of the head 11, and the head 11 coats the object 200. The liquid discharge apparatus 150 according to the present embodiment is preferably applied to a case where the object 200 is light or small enough to be movable by, for example, the robot arm 13. The liquid discharge method in the first embodiment can be adopted in the present embodiment.

[0075] Third EmbodimentA liquid discharge apparatus according to a third embodiment will be described below with reference to FIGS. 22A and 22B. FIGS. 22A and 22B are schematic diagrams illustrating an overall configuration of a liquid discharge apparatus 160 according to the third embodiment. The liquid discharge apparatus 160 includes the head 11, a first guide 800 that moves the head 11 in the main scanning direction (X-axis direction) of the head 11, a fixed guide 810 that unitizes the head 11 and the first guide 800, and a second guide 820 that moves the head 11 in the vertical direction (Y-axis direction) intersecting the scanning direction. The liquiddischarge apparatus 160 is different from the first embodiment in that the head 11 is attached to a component other than the robot arm 13.

[0076] As illustrated in FIGS. 22A and 22B, the head 11 of the liquid discharge apparatus 160 is mounted on the first guide 800 and is movable in the left-right direction (scanning direction). The head 11 and the first guide 800 are unitized by the fixed guide 810 and are movable in the vertical direction along the second guide 820. Accordingly, the head 11 is movable in two- dimensional directions along the first guide 800 and the second guide 820, and can apply liquid to the object 200. The liquid discharge method in the first embodiment can be adopted in the present embodiment.

[0077] Although the liquid discharge apparatus and the liquid discharge method according to an embodiment of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiment. Within a range conceivable by those skilled in the art, another embodiment may be added, or elements may be added, changed, or omitted. Any of such aspects that provides an action and an effect of the present disclosure is within the scope of the present disclosure.

[0078] Aspect 1A liquid discharge apparatus includes a liquid discharge head having multiple nozzles for discharging a liquid onto an object. The liquid discharge apparatus moves the object or the liquid discharge head relative to each other and discharges the liquid. The multiple nozzles include a first nozzle for discharging the liquid in a liquid droplet form and a second nozzle for discharging the liquid continuously (in a seamless liquid stream form). The second nozzle is disposed at an end of the liquid discharge head in a direction intersecting a direction of a relative movement of the object and the liquid discharge head among the multiple nozzles for discharging the liquid.In other words, a liquid discharge apparatus includes a liquid discharge head and a movement mechanism. The liquid discharge head has multiple nozzles including multiple first nozzles arrayed in a nozzle array direction to discharge a liquid in a form of individual liquid droplets from each of the multiple first nozzles onto a coating region of an object and a second nozzle adjacent to one end of the multiple first nozzles to discharge the liquid in a form of seamless liquid stream onto an edge of the coating region of the object. The movement mechanism moves at least one of the object or the liquid discharge head relative to another in a relative movement direction intersecting the nozzle array direction.In addition, the second nozzle is disposed at an end of the liquid discharge head in the nozzle array direction.

[0079] Aspect 2The liquid discharge apparatus according to Aspect 1 includes the multiple first nozzles. An interval between the first nozzles adjacent to each other in the direction intersecting the direction of the relative movement is equal to an interval between the first nozzle and the second nozzle adjacent to each other in the direction intersecting the direction of the relative movement.In other words, an interval between two of the multiple first nozzles adjacent to each other in the nozzle array direction is equal to an interval between the second nozzle and the one end of the multiple first nozzles adjacent to the second nozzle in the nozzle array direction.

[0080] Aspect 3In the liquid discharge apparatus according to Aspect 1 or 2, the second nozzle and at least one of the first nozzles are arranged in the direction of the relative movement.In other words, the second nozzle and at least one of the multiple first nozzles are arranged in the relative movement direction.

[0081] Aspect 4In the liquid discharge apparatus according to any one of Aspects 1 to 3, a diameter of the first nozzle and a diameter of the second nozzle are equal to each other.In other words, a diameter of the multiple first nozzles is equal to a diameter of the second nozzle.

[0082] Aspect 5In the liquid discharge apparatus according to any one of Aspects 1 to 4, a channel that supplies the liquid to be discharged from the first nozzle and the second nozzle to the liquid discharge head includes a common channel.In other words, the liquid discharge apparatus according to Aspects 1 to 4, further comprising a common channel through which the liquid to be discharged from the multiple first nozzles and the second nozzle is supplied to the liquid discharge head.

[0083] Aspect 6In the liquid discharge apparatus according to any one of Aspects 1 to 5, an amount of liquid discharged from the second nozzle per unit time is equal to an amount of liquid discharged from the first nozzle per unit time.In other words, an amount of the liquid discharged from the second nozzle per unit time is equal to an amount of the liquid discharged from each of the multiple first nozzles per unit time.

[0084] Aspect 7The liquid discharge apparatus according to any one of Aspects 1 to 6, includes the multiple liquid discharge heads. In the direction intersecting the direction of the relative movement, a nozzle included in one of the multiple liquid discharge heads is positioned between two nozzles adjacent to each other in the intersecting direction included in another of the multiple liquid discharge heads.In other words, the liquid discharge apparatus according to Aspects 1 to 6, further includes multiple liquid discharge heads including the liquid discharge head. One of the multiple nozzles of one of the multiple liquid discharge heads is positioned between two of the multiple nozzles adjacent to each other of another of the multiple liquid discharge heads in the nozzle array direction.

[0085] Aspect 8The liquid discharge apparatus according to any one of Aspects 1 to 7, includes a controller to control opening and closing of the first nozzle and the second nozzle by a valve body. The controller switches at least one of the first nozzles disposed at an end among the multiple nozzles to the second nozzle. The multiple nozzles are arranged in the direction intersecting the direction of the relative movement.In other words, the liquid discharge apparatus according to Aspects 1 to 7, further includes multiple valves including multiple first valves to respectively open and close the multiple first nozzles and a second valve to open and close the second nozzle, multiple piezoelectric elements including multiple first piezoelectric elements to respectively drive the multiple first valves and a second piezoelectric element to drive the second valve, and circuitry to apply voltages to the multiple piezoelectric elements to move the multiple valves to respectively open and close the multiple nozzles.Further, the circuitry converts at least one of the multiple first nozzles disposed at both ends of the liquid discharge head in the nozzle array direction into the second nozzle.

[0086] Aspect 9In the liquid discharge apparatus according to Aspect 8, the controller switches the first nozzles positioned at both ends in the direction intersecting the direction of the relative movement among the nozzles to the second nozzles.In other words, the circuitry converts each of the multiple first nozzles disposed at both ends of the liquid discharge head in the nozzle array direction into the second nozzle.

[0087] Aspect 10The liquid discharge apparatus according to Aspect 8 or 9, moves the object or the liquid discharge head relative to each other in two-dimensional directions and discharges the liquid into a predetermined region. The controller sets all of the multiple nozzles to the first nozzles when the liquid discharge head discharges the liquid into a region not including an end of thepredetermined region, and sets the nozzle positioned at the end of the predetermined region to the second nozzle when the liquid discharge head discharges the liquid into a region including the end of the predetermined region.In other words, the movement mechanism moves the at least one of the object or the liquid discharge head relative to another in two-dimensional directions. Further, the circuitry sets all of the multiple nozzles to the multiple first nozzles to discharge the liquid into a portion of the coating region other than the edge of the coating region, and set a nozzle of the multiple nozzles disposed at the position facing the edge of the coating region to the second nozzle to discharge the liquid in a portion of the coating region including the edge of the coating region.

[0088] According to another aspect, in the liquid discharge apparatus according to Aspect 9, the circuitry adjusts the voltages to be applied to each of the multiple first piezoelectric elements and the second piezoelectric element to equalize an amount of the liquid discharged from the second nozzle per unit time with an amount of the liquid discharged from each of the multiple first nozzles per unit time.

[0089] Aspect 11In a liquid discharge method by a liquid discharge apparatus, the liquid discharge apparatus discharges a liquid to an object by a liquid discharge head including multiple nozzles. A controller controls discharge of the liquid from the liquid discharge head and a relative movement of the object and the liquid discharge head. The multiple nozzles include a first nozzle for discharging the liquid in a liquid droplet form and a second nozzle for continuously discharging the liquid in a seamless liquid stream form. The second nozzle is disposed at an end of the liquid discharge head in a direction intersecting a direction of the relative movement among the multiple nozzles for discharging the liquid.In other words, a liquid discharge method includes discharging a liquid in a form of individual liquid droplets from multiple first nozzles onto a coating region of an object to form multiple rows of the individual liquid droplets on the coating region of the object, discharging the liquid in a form of seamless liquid stream from a second nozzle onto an edge of the coating region of the object, and moving at least one of a liquid discharge head or the object relative to another.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.

[0090] The present invention can be implemented in any convenient form, for example using dedicated hardware, or a mixture of dedicated hardware and software. The present invention may be implemented as computer software implemented by one or more networked processing apparatuses. The processing apparatuses include any suitably programmed apparatuses such as a general purpose computer, a personal digital assistant, a Wireless Application Protocol (WAP) or third-generation (3G)-compliant mobile telephone, and so on. Since the present invention can be implemented as software, each and every aspect of the present invention thus encompasses computer software implementable on a programmable device. The computer software can be provided to the programmable device using any conventional carrier medium (carrier means). The carrier medium includes a transient carrier medium such as an electrical, optical, microwave, acoustic or radio frequency signal carrying the computer code. An example of such a transient medium is a Transmission Control Protocol / Intemet Protocol (TCP / IP) signal carrying computer code over an IP network, such as the Internet. The carrier medium may also include a storage medium for storing processor readable code such as a floppy disk, a hard disk, a compact disc read-only memory (CD- ROM), a magnetic tape device, or a solid state memory device.

[0091] The functionality of the elements disclosed herein may be implemented using circuitry or processing circuitry which includes general purpose processors, special purpose processors, integrated circuits, application- specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and / or combinations thereof which are configured or programmed, using one or more programs stored in one or more memories, to perform the disclosed functionality. Processors are considered processing circuitry or circuitry as they include transistors and other circuitry therein. In the disclosure, the circuitry, units, or means are hardware that carry out or are programmed to perform the recited functionality. The hardware may be any hardware disclosed herein which is programmed or configured to carry out the recited functionality.There is a memory that stores a computer program which includes computer instructions. These computer instructions provide the logic and routines that enable the hardware (e.g., processing circuitry or circuitry) to perform the method disclosed herein. This computer program can be implemented in known formats as a computer-readable storage medium, a computer program product, a memory device, a record medium such as a CD-ROM or DVD, and / or the memory of an FPGA or ASIC.

[0092] This patent application is based on and claims priority to Japanese Patent Application No. 2023-148497, filed on September 13, 2023, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.[Reference Signs List]

[0093] , 10-1, 10-2, 10-3, 10-4 Liquid discharge unit, 11-1, 11-2, 11-3, 11-4 11A, 11B, 11D, HE head, 12-1, 12-2, 12-3, 12-4 Detector , 13-1, 13-2, 13-3, 13-4 Robot arm Controller 3, 103a, 103b Head unit 0, 150, 160 Liquid discharge apparatus 1 Supply port 2 Collection port 0 Object 0 Valve (an example of a valve body) 1, 31 IL, 31 In Nozzle 2 Channel 0 Liquid droplet 1, 502 Liquid thread

Claims

[CLAIMS]

1. A liquid discharge apparatus comprising: a liquid discharge head having multiple nozzles including: multiple first nozzles arrayed in a nozzle array direction to discharge a liquid in a form of individual liquid droplets from each of the multiple first nozzles onto a coating region of an object; and a second nozzle adjacent to one end of the multiple first nozzles to discharge the liquid in a form of seamless liquid stream onto an edge of the coating region of the object; and a movement mechanism to move at least one of the object or the liquid discharge head relative to another in a relative movement direction intersecting the nozzle array direction.

2. The liquid discharge apparatus according to claim 1, wherein the second nozzle is disposed at an end of the liquid discharge head in the nozzle array direction.

3. The liquid discharge apparatus according to claim 1 or 2, wherein an interval between two of the multiple first nozzles adjacent to each other in the nozzle array direction is equal to an interval between the second nozzle and the one end of the multiple first nozzles adjacent to the second nozzle in the nozzle array direction.

4. The liquid discharge apparatus according to any one of claims 1 to 3, wherein the second nozzle and at least one of the multiple first nozzles are arranged in the relative movement direction.

5. The liquid discharge apparatus according to any one of claims 1 to 4, wherein a diameter of the multiple first nozzles is equal to a diameter of the second nozzle.

6. The liquid discharge apparatus according to any one of claims 1 to 5, further comprising a common channel through which the liquid to be discharged from the multiple first nozzles and the second nozzle is supplied to the liquid discharge head.

7. The liquid discharge apparatus according to any one of claims 1 to 6, wherein an amount of the liquid discharged from the second nozzle per unit time is equal to an amount of the liquid discharged from each of the multiple first nozzles per unit time.

8. The liquid discharge apparatus according to any one of claims 1 to 7, further comprising multiple liquid discharge heads including the liquid discharge head,wherein one of the multiple nozzles of one of the multiple liquid discharge heads is positioned between two of the multiple nozzles adjacent to each other of another of the multiple liquid discharge heads in the nozzle array direction.

9. The liquid discharge apparatus according to any one of claims 1 to 8, further comprising: multiple valves including: multiple first valves to respectively open and close the multiple first nozzles; and a second valve to open and close the second nozzle; multiple piezoelectric elements including: multiple first piezoelectric elements to respectively drive the multiple first valves; and a second piezoelectric element to drive the second valve; and circuitry configured to apply voltages to the multiple piezoelectric elements to move the multiple valves to respectively open and close the multiple nozzles.

10. The liquid discharge apparatus according to claim 9, wherein the circuitry is further configured to convert at least one of the multiple first nozzles disposed at both ends of the liquid discharge head in the nozzle array direction into the second nozzle.

11. The liquid discharge apparatus according to claim 9, wherein the circuitry is further configured to convert each of the multiple first nozzles disposed at both ends of the liquid discharge head in the nozzle array direction into the second nozzle.

12. The liquid discharge apparatus according to any one of claims 9 to 11, wherein the movement mechanism moves the at least one of the object or the liquid discharge head relative to another in two-dimensional directions, and the circuitry is further configured to: set all of the multiple nozzles to the multiple first nozzles to discharge the liquid into a portion of the coating region other than the edge of the coating region, and set a nozzle of the multiple nozzles disposed at the position facing the edge of the coating region to the second nozzle to discharge the liquid in a portion of the coating region including the edge of the coating region.

13. The liquid discharge apparatus according to any one of claims 9 to 12, wherein the circuitry further configured to adjust the voltages to be applied to each of the multiple first piezoelectric elements and the second piezoelectric element to equalize an amount of the liquid discharged from the second nozzle per unit time with an amount of the liquid discharged from each of the multiple first nozzles per unit time.

14. A liquid discharge method comprising: discharging a liquid in a form of individual liquid droplets from multiple first nozzles onto a coating region of an object to form multiple rows of the individual liquid droplets on the coating region of the object; discharging the liquid in a form of seamless liquid stream from a second nozzle onto an edge of the coating region of the object; and moving at least one of a liquid discharge head or the object relative to another.

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