Liquid discharge apparatus and liquid discharge method

Abstract

A liquid discharging apparatus includes a head that discharges liquid onto an object and a moving mechanism that relatively moves the head and the object. The head discharges the liquid that lands on the object. The moving mechanism moves the head relative to the object in a first direction that is perpendicular to a second direction. The head discharges the liquid onto a discharge region on the object. The discharge region has a downstream end region in the first direction. The downstream end region defines a tail end region. The liquid that lands on the tail end region has a length in the second direction that is less than a length in the second direction of the liquid that lands on a region of the discharge region other than the tail end region.

Description

Technical Field

[0001] Embodiments of the present invention relate to a liquid discharge device and a liquid discharge method. Background Technology

[0002] A liquid discharge device is known in which the head discharges liquid onto an object.

[0003] For example, patent document (PTL) 1 discloses an inkjet printer that prints an image at a reduced resolution from a preset resolution upstream of the printer to reduce the impact of secondary droplets.

[0004] [List of Citations]

[0005] [Patent Literature]

[0006] [PTL1]

[0007] Japanese Unexamined Patent Application Publication No. 2015-024599 Summary of the Invention

[0008] [Technical Issues]

[0009] However, the inkjet printer disclosed by PTL1 aims to improve the effects of secondary droplets at the downstream end of the image.

[0010] The purpose of this invention is to reduce the impact caused by secondary droplets.

[0011] [Solution to the problem]

[0012] A liquid discharging device according to an embodiment of the present invention includes a head and a moving mechanism. The head discharges liquid onto an object. The moving mechanism causes relative movement between the head and the object. The head discharges the liquid that has fallen onto the object. The moving mechanism moves the head relative to the object in a first direction perpendicular to a second direction. The head discharges the liquid in a discharging region on the object, the discharging region including a downstream end region in the first direction. The downstream end region defines a tail end region. The length of the liquid falling onto the tail end region in the second direction is less than the length of the liquid falling onto the region of the discharging region other than the tail end region in the second direction.

[0013] [Beneficial effects of the invention]

[0014] The liquid discharge device according to an embodiment of the present invention reduces the impact caused by secondary droplets.

[0015] Attached Figure Description

[0016] A more complete understanding of the embodiments of this disclosure and its many accompanying advantages and features can be readily obtained and understood from the following detailed description with reference to the accompanying drawings.

[0017] [ Figure 1 ]

[0018] Figure 1 This is a view showing the overall structure of a liquid discharge device according to a first embodiment of the present invention.

[0019] [ Figure 2 ]

[0020] Figure 2 This is a perspective view of the head incorporated in a liquid discharge device according to a first embodiment of the present invention, showing the structure of the head.

[0021] [ Figure 3 ]

[0022] Figure 3 Is Figure 2 The cross-sectional view of the head taken from plane S1 depicted in the figure.

[0023] [ Figure 4 ]

[0024] Figure 4 This is a view incorporating the supply section of a liquid discharge device according to a first embodiment of the present invention, showing the structure of the supply section.

[0025] [ Figure 5 ]

[0026] Figure 5 This is a block diagram of a liquid discharge device according to a first embodiment of the present invention, showing its configuration.

[0027] [ Figure 6 ]

[0028] Figure 6 This is a block diagram of a controller incorporated in a liquid discharge device according to a first embodiment of the present invention, illustrating the functional configuration of the controller.

[0029] [ Figure 7 ]

[0030] Figure 7 This is a view of the relative movement path through which the head of the liquid discharge device according to the first embodiment of the present invention moves relative to an object, as an example of a relative movement path.

[0031] [ Figure 8 ]

[0032] Figure 8 This is a schematic diagram of a droplet discharged from a liquid discharge device according to a first embodiment of the present invention, showing a first example of the state of the droplet.

[0033] [ Figure 9]

[0034] Figure 9 It is by Figure 8 A schematic diagram depicting the point where the droplets are generated.

[0035] [ Figure 10 ]

[0036] Figure 10 This is a schematic diagram of a droplet discharged from a liquid discharge device according to a first embodiment of the present invention, showing a second example of the state of the droplet.

[0037] [ Figure 11 ]

[0038] Figure 11 It is by Figure 10 A schematic diagram depicting the point where the droplets are generated.

[0039] [ Figure 12 ]

[0040] Figure 12 This is a schematic diagram of the point on the object from the liquid discharge device according to a first embodiment of the present invention, as a first example.

[0041] [ Figure 13 ]

[0042] Figure 13 This is a schematic diagram of the point on the object from the liquid discharge device according to the first embodiment of the present invention, as a second example.

[0043] [ Figure 14 ]

[0044] Figure 14 This is a schematic diagram of the point on the object from the liquid discharge device according to the first embodiment of the present invention, as a third example.

[0045] [ Figure 15 ]

[0046] Figure 15 This is a diagram illustrating the points that fall on the object as a comparative example.

[0047] [ Figure 16 ]

[0048] Figure 16 This is a graph showing the moving speed of the head of a liquid discharge device according to a first embodiment of the present invention, as a first example.

[0049] [ Figure 17 ]

[0050] Figure 17This is a graph showing the moving speed of the head of the liquid discharge device according to the first embodiment of the present invention, as a second example.

[0051] [ Figure 18 ]

[0052] Figure 18 This is a schematic diagram illustrating the relationship between the droplet discharge cycle as a first example and the thickness of the coating produced by the liquid discharge device according to a first embodiment of the present invention.

[0053] [ Figure 19 ]

[0054] Figure 19 This is a schematic diagram illustrating the relationship between the droplet discharge cycle as a second example and the thickness of the coating produced by the liquid discharge device according to the first embodiment of the present invention.

[0055] [ Figure 20 ]

[0056] Figure 20 This is a schematic diagram illustrating the relationship between the droplet discharge cycle as a third example and the thickness of the coating produced by the liquid discharge device according to the first embodiment of the present invention.

[0057] [ Figure 21 ]

[0058] Figure 21 This is a graph of the drive voltage at the head of a liquid discharge device used as a comparative example.

[0059] [ Figure 22 ]

[0060] Figure 22 This is a graph of the driving voltage of the head of the liquid discharge device according to the first embodiment of the present invention, which serves as a first example.

[0061] [ Figure 23 ]

[0062] Figure 23 This is a graph of the driving voltage of the head of the liquid discharge device according to the first embodiment of the present invention, which serves as a second example.

[0063] [ Figure 24 ]

[0064] Figure 24 This is a graph of the driving voltage of the head of the liquid discharge device according to the first embodiment of the present invention, which serves as a third example.

[0065] [ Figure 25 ]

[0066] Figure 25This is a graph of the driving voltage of the head of the liquid discharge device according to the first embodiment of the present invention, which serves as a fourth example.

[0067] [ Figure 26 ]

[0068] Figure 26 This is a graph of the driving voltage of the head of the liquid discharge device according to the first embodiment of the present invention, which is the fifth example.

[0069] [ Figure 27 ]

[0070] Figure 27 This is a flowchart of a process for setting point data executed by a liquid discharge device according to a first embodiment of the present invention.

[0071] [ Figure 28 ]

[0072] Figure 28 This is a flowchart of a process performed by the liquid discharge device of the first embodiment of the present invention to determine parameters for dealing with secondary droplets.

[0073] [ Figure 29 ]

[0074] Figure 29 This is a schematic diagram of the head of the liquid discharge device according to the first embodiment of the present invention reciprocating relative to the object.

[0075] [ Figure 30 ]

[0076] Figure 30 This is a schematic diagram of the reciprocating movement of the head of a liquid discharge device relative to an object according to a first embodiment of the present invention, showing the first discharge performed by the head.

[0077] [ Figure 31A ]

[0078] Figure 31A This is a schematic diagram of the reciprocating movement of the head of a liquid discharge device relative to an object according to a first embodiment of the present invention, showing a second discharge performed by the head.

[0079] [ Figure 31B ]

[0080] Figure 31B This is a schematic diagram of the reciprocating movement of the head of a liquid discharge device relative to an object according to a first embodiment of the present invention, showing a second discharge performed by the head.

[0081] [ Figure 32 ]

[0082] Figure 32This is a schematic diagram of the head of a liquid discharge device according to a first embodiment of the present invention reciprocating relative to an object, showing a third discharge performed by the head.

[0083] [ Figure 33 ]

[0084] Figure 33 This is a schematic diagram of the head of a liquid discharge device according to a first embodiment of the present invention reciprocating relative to an object, showing a fourth discharge pattern performed by the head.

[0085] [ Figure 34 ]

[0086] Figure 34 This is a view of the head of a liquid discharge device according to a first embodiment of the present invention, showing the discharge area as a first example.

[0087] [ Figure 35 ]

[0088] Figure 35 This is a view of the head of a liquid discharge device according to a first embodiment of the present invention, showing the discharge area as a second example.

[0089] [ Figure 36 ]

[0090] Figure 36 This is a view of the head of a liquid discharge device according to a first embodiment of the present invention, showing the discharge area as a third example.

[0091] [ Figure 37 ]

[0092] Figure 37 This is a view of a liquid discharge device according to a second embodiment of the present invention, showing its structure.

[0093] [ Figure 38 ]

[0094] Figure 38 This is a view of a liquid discharge device according to a third embodiment of the present invention, showing its structure.

[0095] [ Figure 39 ]

[0096] Figure 39 Is Figure 38 A cross-sectional view of the liquid discharge device taken from the XXXIX-XXXIX line.

[0097] The accompanying drawings are intended to depict embodiments of this disclosure and should not be construed as limiting its scope. Unless explicitly stated otherwise, the drawings are not considered to be drawn to scale. Furthermore, throughout the several views, the same or similar reference numerals denote the same or similar parts. Detailed Implementation

[0098] A detailed description of a liquid discharge device and liquid discharge method according to embodiments of the present invention is provided with reference to the accompanying drawings. The embodiments described below depict liquid discharge devices and liquid discharge methods that implement the technology of embodiments of the present invention, but are not limited to those described below. As examples, the embodiments describe elements having dimensions, materials, shapes, relative positions, etc., which do not limit the scope of the invention unless otherwise described. The drawings may emphasize the dimensions, positional relationships, etc., of components to clarify the description. In the following description, components with the same names and reference numerals denote the same or equivalent components, and detailed descriptions of these components are appropriately omitted.

[0099] As an example, a description of the overall structure of a liquid discharge device 100 according to a first embodiment of the present invention is provided. Figure 1 This is a view of a liquid discharging device 100 according to a first embodiment of the present invention, showing an example of its overall structure. The liquid discharging device 100 includes a liquid discharging device 10, a head 11, and a moving mechanism 13. The moving mechanism 13 moves the head 11 relative to the object 200 in a first direction. Figure 1 The liquid discharge device 100 depicted, by way of example, also includes a control unit 20 for controlling the liquid discharger 10.

[0100] The liquid discharge device 100 includes four liquid dischargers 10, namely liquid dischargers 10-1, 10-2, 10-3, and 10-4. The four liquid dischargers 10 (e.g., liquid dischargers 10-1, 10-2, 10-3, and 10-4) surround the object 200 located at the coating position. Each of the four liquid dischargers 10 (e.g., liquid dischargers 10-1, 10-2, 10-3, and 10-4) includes a head 11 for discharging liquid onto the object 200 and a moving mechanism 13. As an example... Figure 1 The liquid discharger 10 depicted includes a detector 12.

[0101] For example, object 200 is the body of a vehicle. Vehicles include cars, trucks, etc. Object 200 described as an example in this specification is a vehicle.

[0102] Each of the heads 11 (e.g., heads 11-1, 11-2, 11-3, and 11-4) includes multiple nozzles for discharging liquid and is mounted on the tip of the moving mechanism 13. The moving mechanism 13 moves the head 11 relative to the object 200. As an example... Figure 1 The depicted moving mechanism 13 moves the head 11 relative to the object 200 along the surface of the object 200. When the moving mechanism 13 moves the head 11 relative to the object 200, the nozzle of the head 11 discharges liquid applied to the object 200, thereby coating the object 200.

[0103] Each of the detectors 12 (e.g., detectors 12-1, 12-2, 12-3, and 12-4) is mounted on the tip of the moving mechanism 13. The detectors 12 output feature point data relating to the three-dimensional positions of three or more feature points on the object 200. The detectors 12 include three-dimensional (3D) cameras such as stereo cameras, three-dimensional (3D) sensors other than stereo cameras, laser displacement gauges, etc. As an example... Figure 1 The detector 12 depicted includes a stereo camera that performs measurements of the position of the head 11 in the X and Y directions, the tilt of the head 11, the detection of the coating start position of the head 11, and the detection of the size of the object 200 to be coated. The detector 12 includes multiple stereo cameras. Based on the parallax between images captured by the multiple stereo cameras, the detector 12 obtains a distance image of the object 200 using triangulation. The stereo cameras output the distance image as feature point data to the control unit 20. Alternatively, the detector 12 may include a laser displacement meter that performs measurements of the position of the head 11 in the Z direction, the detection of the height of the top of the object 200, and the curvature of the object 200.

[0104] Each of the moving mechanisms 13 (e.g., moving mechanisms 13-1, 13-2, 13-3, and 13-4) includes a link and a joint. As the moving mechanism 13 rotates or moves the links and joints, the moving mechanism 13 changes the position and tilt of the head 11 relative to the object 200, such that the nozzle plate of the head 11 faces the object 200.

[0105] Based on the predetermined shape data of the object 200 and the feature point data related to the three-dimensional position of three or more feature points output from the four detectors 12 respectively, the control unit 20 drives the moving mechanism 13 that holds the four heads 11 respectively.

[0106] Besides serving as an example Figure 1 In addition to the components depicted, the liquid discharge device 100 may also include a supply section and a maintenance section. The supply section supplies liquid to four heads 11 that discharge liquid onto the object 200. The maintenance section removes thickener, foreign matter, etc., adhering to the surface of the nozzle plate of the head 11 or from inside the head 11. The maintenance section of the liquid discharge device 100 reduces undesirable discharge from the head 11, such as nozzle malfunction, liquid jet deviation, and changes in discharge speed, thereby maintaining proper discharge from the head 11.

[0107] In the liquid discharge device 100, after the object 200 is conveyed to the coating position, the moving mechanism 13 moves the head 11 relative to the stationary object 200, so that the head 11 coats the object 200. When the head 11 has finished coating the object 200, the object 200 is conveyed to a position outside the coating position, so that subsequent objects 200 are conveyed to the coating position.

[0108] Reference Figure 2 and Figure 3 A description of the structure of the head 11 incorporated in the liquid discharge device 100 is provided. Figure 2 This is a view of the head 11 according to the first embodiment, which shows an example of the structure of the head. Figure 3 According to the first embodiment Figure 2 A cross-sectional view taken from the plane S1. (See figure.) Figure 2 and Figure 3 As shown, the head 11 includes a supply port 111, a collection port 112, and a discharge module 340.

[0109] Supply port 111 supplies pressurized liquid, pressurized externally to head 11, to discharge module 340. Collection port 112 discharges liquid that is not discharged when nozzle 311 is open (described later) to the outside of head 11. Discharge module 340 includes body 110, nozzle plate 321 with nozzle 311, channel 322 for liquid, valve 310, and piezoelectric element 324. Nozzle plate 321 is connected to body 110 and discharges liquid supplied from supply port 111 through nozzle 311. Channel 322 connects to multiple discharge modules 340 mounted on body 110 (e.g., ...). Figure 3 The eight discharge modules 340 described in the text are shared.

[0110] Figure 3 The valve 310 depicted is a needle valve. A piezoelectric element 324 drives the valve 310. When the valve 310 reciprocates within the body 110 in the liquid discharge direction, the valve 310 opens and closes the nozzle 311. With the valve at the collection port 112 closed, fluid flows from the supply port 111 through the flow path 322 to... Figure 3 The head 11 shown supplies pressurized liquid. When valve 310 is in the position where valve 310 closes nozzle 311, nozzle 311 does not discharge liquid. Instead, as piezoelectric element 324 is actuated to lift valve 310, nozzle 311 opens and discharges liquid.

[0111] A description of the structure of the supply section 14 incorporated in the liquid discharge device 100 is provided. Figure 4This is a schematic diagram of the supply section 14 incorporated in the liquid discharge device 100, showing its structure as an example. The supply section 14 includes liquid tanks 330, namely liquid tanks 330-1, 330-2, 330-3, and 330-4, which serve as sealed containers and contain liquid 325 discharged from heads 11-1, 11-2, 11-3, and 11-4, respectively. The liquid tanks 330 are connected to the inlets (e.g., supply ports 111) of heads 11-1, 11-2, 11-3, and 11-4 via pipes 333, such that liquid 325 flows from the liquid tanks 330 to heads 11-1, 11-2, 11-3, and 11-4 through the pipes 333.

[0112] Liquid tank 330 is connected to compressor 230 via pipe 331 equipped with air conditioner 332. Compressor 230 supplies compressed air, which in turn supplies pressurized liquid 325 to the inlet of head 11. Liquid 325 is then discharged from nozzle 311 of head 11 of liquid discharge device 100. Instead of separate liquid tanks 330 for each head 11, a single liquid tank 330 can supply liquid 325 to head 11.

[0113] A description of the configuration of control unit 20 is provided. Figure 5 This is a block diagram of a liquid discharge device 100, illustrating its configuration as an example. The liquid discharge device 100 includes a controller 901, a head control unit 902, a movement mechanism control unit 904, an input device 905, movement mechanisms 13-1 and 13-2, and a personal computer (PC) 903.

[0114] The controller 901 includes a central processing unit (CPU) 9001, a read-only memory (ROM) 9002, a random access memory (RAM) 9003, and an interface (I / F) 9004. The controller 901, the head control unit 902, and the movement mechanism control unit 904 constitute the control unit 20. The head 11 and the detector 12 constitute the head unit 103. The movement mechanisms 13-1 and 13-2 are... Figure 1 Two of the four moving mechanisms 13 depicted.

[0115] PC 903 includes a coating path generation unit 9031 and a coating data generation unit 9032. Figure 5 The depicted coating path generation unit 9031 and coating data generation unit 9032 define the functional units of PC 903. The coating path generation unit 9031 and coating data generation unit 9032 have functions created when the CPU integrated in PC 903 executes processes specified by programs stored in memory such as ROM.

[0116] The coating path generation unit 9031 obtains position data from the detector 12 mounted on the moving mechanism 13 and generates a coating path as the path through which the head 11 moves using the moving mechanism 13. The coating data generation unit 9032 generates coating point data based on the coating path generated by the coating path generation unit 9031. The coating data generation unit 9032 includes a discharge frequency generation unit 9033, a movement speed generation unit 9034, and a raster image processor (RIP) 9035. In the coating data generation unit 9032, the discharge frequency generation unit 9033 generates the discharge frequency of the liquid discharged by the head 11 based on the generated point data. The movement speed generation unit 9034 generates the movement speed at which the head 11 moves using the moving mechanism 13 and generates the driving conditions for the head 11, thereby creating the coating data.

[0117] RIP 9035 performs image processing according to a color profile or user-specified settings. RIP 9035 includes a rendering unit 9036. The rendering unit 9036 decomposes coating data used for coating the object 200 into image data. During coating of the object 200 by the head 11, the liquid discharge device 100 moves the head 11 in a main scanning direction and a sub-scanning direction perpendicular to the main scanning direction. The image data defines the data included in the coating data and used for coating each time the head 11 moves in the main scanning direction.

[0118] PC 903 is connected to input device 905, which performs actions such as setting image and coordinate data for coating object 200, selecting coating mode, setting coating range (e.g., coating start and end positions), and coating instructions. Input device 905 includes a keyboard, mouse, and touch panel, and receives input from the user.

[0119] The controller 901 is connected to the PC 903. The CPU 9001 is a processing unit that reads programs or data stored in ROM 9002, etc., into RAM 9003 and performs processing to realize the function of the liquid discharge device 100 used as a coating robot. The controller 901 may also include a hard disk drive (HDD), solid-state drive (SSD), etc.

[0120] The CPU 9001 controls the overall operation of the liquid dispensing device 100 based on image data or instructions received from the PC 903. The ROM 9002 is a non-volatile memory that retains programs or data even when the liquid dispensing device 100 is powered off. The RAM 9003 is a volatile memory used as the working area of ​​the CPU 9001, etc. The I / F 9004 is an interface for inputting and outputting characters, values, instructions, etc., to external devices, etc. The I / F 9004 is the interface through which the controller 901 communicates with external devices such as the PC 903.

[0121] The moving mechanism 13 includes a head unit 103, an encoder sensor 109, and a driver 72. The head 11 discharges liquid according to a drive signal sent from the head control unit 902. The detector 12 sends the detection result of the object 200 to the PC 903.

[0122] For example, each of the encoder sensors 109 optically detects the slits of the encoder mounted on each of the first joint, second joint, third joint, etc. The encoder sensors 109 detect the position of the slits based on the amount of rotation of the moving mechanisms 13-1 and 13-2, respectively, thereby obtaining three-dimensional position data of the head unit 103.

[0123] The driver 72 moves the head unit 103, supported by the moving mechanism 13, to the target position according to the drive signal sent from the moving mechanism control unit 904. The head control unit 902 and the moving mechanism control unit 904 are shared by the moving mechanisms 13-1 and 13-2. Alternatively, the head control unit 902 and the moving mechanism control unit 904 can be configured for each of the moving mechanisms 13-1 and 13-2. The RIP 9035, including the rendering unit 9036, can be integrated into the controller 901 instead of the PC 903.

[0124] The head control unit 902 receives a discharge cycle signal from the controller 901 and controls the discharge of liquid from the head 11 based on the discharge cycle signal. The movement mechanism control unit 904 receives a synchronization control signal from the controller 901 and controls the drive of the driver 72 based on the synchronization control signal. The movement mechanism control unit 904 controls the drive of the driver 72, causing the movement mechanism 13, including the head unit 103, to move to the target position.

[0125] Provides a description of the functional configuration of controller 901. Figure 6This is a block diagram of the controller 901 integrated with the liquid discharge device 100 according to a first embodiment of the present invention, showing an example of the functional configuration of the controller 901. The controller 901 includes a system control unit 9011, a data storage unit 9012, a memory control unit 9013, a discharge cycle signal generation unit 9014, and a cycle control unit 9015.

[0126] The system control unit 9011 controls the overall operation of the liquid discharge device 100 based on image data or instructions received from the PC 903. The data storage unit 9012 stores coating data, etc., received from the PC 903. The memory control unit 9013 controls the data storage unit 9012. The discharge cycle signal generation unit 9014 generates a liquid discharge cycle signal based on the output signal from the encoder sensor 109 and data representing the resolution of the image data received from the PC 903. The cycle control unit 9015, based on image data, coating instructions, etc., received from the PC 903, synchronizes the movement of the moving mechanisms 13-1 and 13-2 with the liquid discharge from the heads 11-1 and 11-2.

[0127] Provides a description of the relative movement path taken by the head 11 relative to the object 200. Figure 7 This is a view of object 200 and, as an example, a relative movement path through which the head 11 of the liquid discharge device 100 according to a first embodiment of the present invention moves relative to object 200.

[0128] Figure 7 The diagram shows a coating area 211 (e.g., coating areas 211-1, 211-2, 211-3, and 211-4) on an object 200 of a car and on the roof 201 of the car. The coating area 211 defines the region described above. Figure 1 The four moving mechanisms 13 depicted move the head 11 relative to the object 200 so that the head 11 coats the object 200. The four heads 11 are provided with different coating areas 211 and relative movement paths T10 (e.g., relative movement paths T1-1, T1-2, T1-3 and T1-4).

[0129] The coating area 211-1 defines the area where the moving mechanism 13-1 moves the head 11-1 relative to the object 200 to coat the object 200. The relative movement path T1-1 defines the path traversed by the head 11-1 relative to the object 200.

[0130] The coating area 211-2 defines the area where the moving mechanism 13-2 moves the head 11-2 relative to the object 200 to coat the object 200. The relative movement path T1-2 defines the path traversed by the head 11-2 relative to the object 200.

[0131] The coating area 211-3 defines the area where the moving mechanism 13-3 moves the head 11-3 relative to the object 200 to coat the object 200. The relative movement path T1-3 defines the path traversed by the head 11-3 relative to the object 200.

[0132] The coating area 211-4 defines the area where the moving mechanism 13-4 moves the head 11-4 relative to the object 200 to coat the object 200. The relative movement path T1-4 defines the path traversed by the head 11-4 relative to the object 200.

[0133] As described above, the liquid discharge device 100 includes four moving mechanisms 13, which respectively move four heads 11 relative to the roof 201 of the vehicle 200, so that the heads 11 discharge liquid applied to the roof 201.

[0134] This describes the liquid discharged from the head as the head moves in the main scanning direction. The state of intermittent liquid discharge by the head is defined as follows: during the movement of the head in the main scanning direction, the head periodically repeats the discharge and interruption of liquid discharge. For example, the state of intermittent liquid discharge by the head is defined as the state of the head discharging droplets. Conversely, the state of continuous liquid discharge by the head is defined as follows: during the movement of the head in the main scanning direction, the head continuously discharges liquid. In other words, the state of continuous liquid discharge by the head is defined as follows: during the movement of the head in the main scanning direction, the head discharges liquid uninterruptedly or in a continuous flow in the main scanning direction. In the following description, intermittently discharged liquid may be referred to as droplets. Continuously discharged liquid may be referred to as liquid filaments.

[0135] When droplets are discharged from the liquid discharge device, the droplets that fall onto the object to be coated wet and spread in a circular motion, thus forming dots. The formed dots overlap with surrounding dots and fill the gaps between the dots, thereby forming the coated surface. Because the formed dots have a circular shape, the coated surface has a wavy edge based on the circular shape of the dots.

[0136] Conversely, when the liquid filaments are discharged from the liquid discharge device, the liquid filaments landing on the object to be coated do not form dots, but rather form filaments in the main scanning direction of the movement of the head of the liquid discharge device. Therefore, the coated surface has edges in the secondary scanning direction that are smoother in the main scanning direction.

[0137] A description of the operation of the liquid discharge device 100 is provided. A description of the reduction of the effect on secondary droplets performed by the liquid discharge device 100 is now given. The following description is given with reference to a droplet as an example. However, the basic concepts are shared with liquid filaments.

[0138] As valve 310 opens and closes, head 11 discharges liquid in the form of droplets, i.e., liquid droplets. As liquid is discharged from head 11, it falls onto object 200. As the liquid discharged from head 11 falls onto object 200, it forms a point on object 200. After valve 310 opens, control unit 20 controls the time period required until valve 310 closes, thereby controlling the volume of the droplets discharged from head 11. As the time period required from valve 310 opening to valve 310 closing increases, the droplet volume increases. As the droplet volume increases, the diameter of the substantially circular point formed on object 200 increases.

[0139] Depending on the liquid's viscosity, surface tension, etc., the droplet discharged from head 11 may produce a tail called a ligament, which follows the droplet in the direction of its travel through the air. If the ligament separates from the droplet during its travel through the air, the separated ligament atomizes into tiny droplets following the droplet due to the liquid's surface tension. In this specification, the main body of the droplet, excluding the ligament, is called the main droplet. The tiny droplets generated as the ligament separates from the main droplet and is atomized are called secondary droplets. Secondary droplets have a volume smaller than that of the main droplet. Because secondary droplets are spaced apart from the main droplet, they are also called satellite droplets. As the main droplet lands on object 200, a main droplet formation point is formed. As secondary droplets land on object 200, satellite droplets are formed.

[0140] Reference Figures 8 to 11 It provides a description of the relationship between the state of the droplets discharged from head 11 and the points formed by the droplets. Figure 8 This is a schematic diagram of a droplet discharged by a liquid discharge device 100 according to a first embodiment of the present invention, showing the droplet state as a first example. Figure 9 It is by Figure 8 A schematic diagram depicting the point and satellite points where the droplet forms. Figure 10 This is a schematic diagram of a droplet discharged from a liquid discharge device 100 according to a first embodiment of the present invention, showing the droplet state as a second example. Figure 11 It is by Figure 10 A schematic diagram depicting the point and satellite points where the droplet forms. Figure 8 and Figure 10 The state of the droplet is shown as viewed from a direction substantially perpendicular to the discharge direction C from the head 11. Figure 9 and Figure 11The diagram shows the points and satellite points formed on object 200 by droplets falling on object 200, as viewed from a direction parallel to the normal vector of object 200.

[0141] Figure 8 A droplet 80a is shown as a first example. The droplet 80a includes a main droplet 81a and a liquid line 82a following the main droplet 81a. Figure 8 The diagram shows a droplet 80a1 generated after a predetermined time has elapsed following the generation of droplet 80a. Droplet 80a1 comprises a plurality of secondary droplets 83a, which are generated as the liquid line 82a separates from the main droplet 81a and the separated liquid line 82a is atomized according to the surface tension of the liquid.

[0142] Figure 9 The diagram shows a point 91a formed by a main droplet 81a and a satellite point 92a formed by a plurality of secondary droplets 83a, as a first example. Length L1 defines the distance from the position of the end of point 91a to the position of the end of satellite point 92a, wherein the end of point 91a is positioned opposite to satellite point 92a in a first direction A of movement of head 11, and the end of satellite point 92a is opposite to another end of satellite point 92a positioned opposite to point 91a in the first direction A. According to an embodiment of the invention, the first direction A defines a direction (e.g., the main scanning direction) in which the moving mechanism 13 moves head 11 relative to object 200 when head 11 discharges liquid in the discharge area on object 200 to form a point.

[0143] Figure 10 The droplet 80b is shown as a second example. The droplet 80b includes a main droplet 81b and a liquid line 82b following the main droplet 81b. Figure 10 Also shown is a droplet 80b1 generated after a predetermined time has elapsed following the generation of droplet 80b. Droplet 80b1 comprises a plurality of secondary droplets 83b, which are generated as the liquid line 82b separates from the main droplet 81b and the separated liquid line 82b is atomized according to the surface tension of the liquid.

[0144] Figure 11 The diagram shows a point 91b formed by a main droplet 81b and a satellite point 92b formed by a plurality of secondary droplets 83b, as a second example. A length L2 defines the distance from the position of the end of point 91b to the position of the end of satellite point 92b, wherein the end of point 91b is positioned opposite to satellite point 92b in a first direction A, and the end of satellite point 92b is opposite to another end of satellite point 92b positioned opposite to point 91b in the first direction A.

[0145] Figure 8 The liquid volume and quantity of the described droplet 80a are greater than Figure 10The depicted droplet 80b has a larger liquid volume. Because droplet 80a has a larger liquid volume, the length of liquid line 82a in the discharge direction C is greater than the length of liquid line 82b. Because liquid line 82a has a larger length, the number of secondary droplets 83a generated by liquid line 82a is greater than the number of secondary droplets 83b generated by liquid line 82b. Furthermore, the total length defined by the plurality of secondary droplets 83a arranged in the discharge direction C is greater than the total length defined by the plurality of secondary droplets 83b arranged in the discharge direction C. Because the plurality of secondary droplets 83a arranged in the discharge direction C defines a larger total length, on object 200, Figure 9 The area of ​​the depicted satellite point 92a is greater than Figure 11 The area of ​​the depicted satellite point 92b. The length L1 defined by the satellite points 92a arranged in the first direction A is greater than the length L2 defined by the satellite points 92b.

[0146] For example, if the size of the satellite points increases, or the length defined by the satellite points arranged in the first direction A increases, excess liquid may adhere to the object 200, thereby soiling the object 200.

[0147] Reference Figures 12 to 15 This provides a description of points formed on an object 200 by a liquid discharge device 100 according to a first embodiment of the present invention. Figure 12 This is a schematic diagram, as a first example, showing how a point 91 is placed on a coating object 200 by a liquid discharge device 100 according to a first embodiment of the present invention. Figure 13 This is a schematic diagram, as a second example, showing how a point 91 is placed on a coating object 200 by a liquid discharge device 100 according to a first embodiment of the present invention. Figure 14 This is a schematic diagram, as a third example, showing how a point 91 is placed on a coating object 200 by a liquid discharge device 100 according to a first embodiment of the present invention. Figure 15 This is a schematic diagram of point 91 falling on object 200 as a comparative example. Figures 12 to 14 Point 91 is shown to be assigned reference numerals 911 and 912, indicating that point 91 includes points 911 and 912. Figure 15 Point 91 is indicated by reference numerals 911 and 912X, which indicate that point 91 includes points 911 and 912X. The front and rear regions of the discharge region 120 are described below. The front region defines an upstream region in a first direction A. The rear region defines a downstream region in the first direction A. A direction perpendicular to the first direction A is defined as a second direction.

[0148] exist Figures 12 to 14In the depicted liquid discharge device 100, the discharge region 120 on the object 200 to which liquid is discharged has a tail region 121 and an outer region in the first direction A, excluding the tail region 121. The diameter dc of point 912 in the tail region 121 is smaller than the diameter d of point 911 in the outer region. Therefore, the length of liquid falling on the tail region 121 in the second direction is less than the length of liquid falling on the outer region in the second direction.

[0149] For example, the head 11 of the liquid discharge device 100 discharges liquid into the tail region 121 of the discharge region 120. Figure 18 The amount of droplets 80 depicted is less than the amount of droplets 80 discharged into the outer region of the discharge area 120, excluding the tail region 121. Therefore, the diameter dc of point 912 in the tail region 121 is less than the diameter d of point 911 in the outer region excluding the tail region 121. Because the amount of droplets 80 is reduced, the length of the liquid line is reduced. Therefore, the liquid discharge device 100 reduces the impact caused by secondary droplets. Because the impact caused by secondary droplets is reduced, the liquid discharge device 100 reduces satellite points, thereby preventing excess liquid from adhering to and soiling the object 200. Each of the first to third examples reduces the impact caused by secondary droplets.

[0150] The tail region 121 defines a span that extends upstream from the rear end of the discharge region 120 in a first direction A of movement of the head 11 by a length not less than the diameter d of point 911. The diameter dc of point 912 is preferably not greater than 90% of the diameter d of point 911.

[0151] exist Figure 15 In the comparative example shown, the discharge region 120X includes a tail region 121X, in which the amount of droplets 80 discharged from the head 11 is not less than the amount of droplets 80 discharged into the outer regions of the discharge region 120X excluding the tail region 121X. Therefore, compared with Figure 12 The first example described Figure 13 The second example depicted and Figure 14 Compared to satellite point 92 in the third example depicted, satellite point 92X in the comparative example has more satellite points and is larger in size.

[0152] A description is provided of the reduction in the thickness unevenness of the coating produced by the liquid discharge device 100.

[0153] For example, if the amount of droplets 80 in the tail region 121 is less than the amount of droplets 80 in the outer region excluding the tail region 121, the thickness of the coating in the tail region 121 may be less than the thickness of the coating in the outer region excluding the tail region 121, resulting in uneven coating thickness.

[0154] exist Figure 12 In the first example of the liquid discharge device 100 depicted, the center-to-center distance pc between adjacent points 912 in the first direction A in the tail region 121 is less than the center-to-center distance p between adjacent points 911 in the first direction A in the outer region of the discharge region 120 excluding the tail region 121. Therefore, the amount of droplets 80 in the tail region 121 is equal to the amount of droplets 80 in the outer region excluding the tail region 121. Consequently, the thickness of the coating in the tail region 121 is equal to the thickness of the coating in the outer region excluding the tail region 121, thereby reducing coating thickness unevenness.

[0155] exist Figure 13 In the second example of the liquid discharge device 100 depicted, with Figure 12 Compared to the first example of the liquid discharge device 100 depicted, the center-to-center distance pc between adjacent points 912 in the first direction A in the tail region 121 of the discharge region 120 is further reduced. Also in the second example of the liquid discharge device 100, the amount of droplets 80 in the tail region 121 is equal to the amount of droplets 80 in the outer region excluding the tail region 121.

[0156] exist Figure 14 In the third example of the liquid discharge device 100 depicted, as the head 11 moves in the tail region 121 along the first direction A, the diameter dc of point 912 gradually decreases. Furthermore, the center-to-center distance pc between adjacent points 912 along the first direction A decreases. Also in this third example of the liquid discharge device 100, the amount of droplets 80 in the tail region 121 is equal to the amount of droplets 80 in the outer region excluding the tail region 121.

[0157] In order to reduce the unevenness of the coating produced by the liquid discharge device 100, the moving speed of the head 11 relative to the object 200 in the tail region 121 can be lower than the moving speed of the head 11 relative to the object 200 in the outer region of the discharge region 120 other than the tail region 121. Figure 16 This is a graph illustrating a first example of the moving speed of the head 11 of the liquid discharge device 100 according to a first embodiment of the present invention. Figure 17 This is a graph illustrating a second example of the moving speed of the head 11 of the liquid discharge device 100 according to a first embodiment of the present invention. For example, the liquid discharge device 100 controls the number of rotations of the gears of the moving mechanism 13, thereby controlling the moving speed of the head 11.

[0158] exist Figure 16In the process, the first time period T1 defines the time period when the head 11 discharges liquid in the outer region of the discharge area 120, excluding the tail region 121. The second time period T2 defines the time period when the head 11 discharges liquid in the tail region 121 of the discharge area 120. In the second time period T2, the moving speed of the head 11 in the first direction A is slower than the moving speed of the head 11 in the first direction A in the first time period T1. The amount of droplets 80 discharged by the head 11 at the slower moving speed onto the tail region 121 is greater than the amount of droplets 80 discharged when the head 11 moves at the higher moving speed. Therefore, the amount of droplets 80 in the tail region 121 is equal to the amount of droplets 80 in the outer region excluding the tail region 121. Therefore, the thickness of the coating in the tail region 121 is equal to the thickness of the coating in the outer region excluding the tail region 121, thereby reducing coating thickness unevenness.

[0159] like Figure 17 As shown, as the head 11 moves, its moving speed in the first direction A gradually decreases during the second time period T2. Even with the decreasing moving speed of the head 11, the amount of droplets 80 in the tail region 121 increases compared to when the head 11 moves at an increasing speed. Therefore, the amount of droplets 80 in the tail region 121 is equivalent to the amount of droplets 80 in the outer region excluding the tail region 121. Consequently, the coating thickness in the tail region 121 is equivalent to the coating thickness in the outer region excluding the tail region 121, thereby reducing coating thickness unevenness.

[0160] Reference Figures 18 to 20 This provides a description of the relationship between the discharge cycle of the head 11 of the liquid discharge device 100 according to a first embodiment of the present invention and the thickness of the coating. Figure 18 This is a schematic diagram as a first example illustrating the relationship between the discharge cycle of the head 11 of the liquid discharge device 100 according to a first embodiment of the present invention and the thickness of the coating film. Figure 19 This is a schematic diagram as a second example illustrating the relationship between the discharge cycle of the head 11 of the liquid discharge device 100 according to a first embodiment of the present invention and the thickness of the coating film. Figure 20 This is a schematic diagram as a third example illustrating the relationship between the discharge cycle of the head 11 of the liquid discharge device 100 according to a first embodiment of the present invention and the thickness of the coating film.

[0161] Figures 18 to 20 The discharge cycle q1 of droplets 80 and the thickness t1 of coating 180 in the first time period T1 are shown, and the discharge cycle q2 of droplets 80 and the thickness t2 of coating 180 in the second time period T2 are shown. Coating 180 defines the film of the coated object 200.

[0162] exist Figure 18 In the first example shown, the amount of droplets 80 discharged in the second time period T2 is less than the amount of droplets 80 discharged in the first time period T1. The discharge cycle q2 in the second time period T2 is equivalent to the discharge cycle q1 in the first time period T1. Therefore, in the first example, the thickness t2 of the coating film 180 produced in the second time period T2 is less than the thickness t1 of the coating film 180 produced in the first time period T1.

[0163] exist Figure 19 In the second example shown, the amount of droplets 80 discharged in the second time period T2 is less than the amount of droplets 80 discharged in the first time period T1. The discharge cycle q2 in the second time period T2 is shorter than the discharge cycle q1 in the first time period T1. As the discharge cycle q2 shortens, the amount of droplets 80 discharged onto the object 200 increases. Therefore, in the second example, the thickness t2 of the coating film 180 produced in the second time period T2 is substantially equal to the thickness t1 of the coating film 180 produced in the first time period T1. If the discharge cycle q2 in the second time period T2 is the same as the discharge cycle q1 in the first time period T1, the thickness t2 of the coating film 180 produced in the second time period T2 may be less than the thickness t1 of the coating film 180 produced in the first time period T1. In this case, the thickness unevenness of the coating film 180 may increase. Conversely, in the second example, the thickness t2 of the coating film 180 produced in the second time period T2 is substantially equal to the thickness t1 of the coating film 180 produced in the first time period T1, thereby reducing the thickness unevenness of the coating film 180.

[0164] exist Figure 20 In the third example shown, the amount of droplets 80 discharged in the second time period T2 is less than the amount of droplets 80 discharged in the first time period T1. Furthermore, as the head 11 moves in the first direction A, the amount of droplets 80 discharged in the second time period T2 gradually decreases. The discharge cycle q2 in the second time period T2 is shorter than the discharge cycle q1 in the first time period T1. Additionally, as the head 11 moves in the first direction A, the discharge cycle q2 gradually shortens. As the discharge cycle q2 shortens, the amount of droplets 80 discharged onto the object 200 increases. Therefore, in the third example, the thickness t2 of the coating 180 produced in the second time period T2 is substantially equal to the thickness t1 of the coating 180 produced in the first time period T1. Therefore, in the third example, the thickness of the coating 180 decreases unevenly.

[0165] Reference Figures 21 to 26 This provides a description of the driving voltage applied to the head 11 of the liquid discharge device 100 according to a first embodiment of the present invention. Figure 21 This is a graph showing, as an example, the driving voltage applied to the head 11 of the liquid discharge device 100 according to the comparative example. Figure 22This is a graph showing, as a first example, the driving voltage applied to the head 11 of the liquid discharge device 100 according to a first embodiment of the present invention. Figure 23 This is a graph showing, as a second example, the driving voltage applied to the head 11 of the liquid discharge device 100 according to the first embodiment of the present invention. Figure 24 The graph shown is a third example illustrating the driving voltage applied to the head 11 of the liquid discharge device 100 according to the first embodiment of the present invention. Figure 25 The graph shown is a fourth example illustrating the driving voltage applied to the head 11 of the liquid discharge device 100 according to the first embodiment of the present invention. Figure 26 The graph shown is a fifth example illustrating the driving voltage of the head 11 of the liquid discharge device 100 according to the first embodiment of the present invention.

[0166] exist Figure 21 In the comparative example shown, the liquid discharge device 100 applies a driving voltage V1 to the head 11 at a discharge cycle q1 during the opening period Δ1. As the valve 310 moves by an amount according to the driving voltage V1, the nozzle 311 opens and discharges liquid according to the amount of movement of the valve 310 and the opening period Δ1. In this case, the amount of liquid is not less than the amount of liquid discharged in the outer region of the discharge region 120 excluding the tail region 121. Therefore, the number and size of the satellite points generated in the comparative example may be increased compared to the satellite points generated in the first to fifth examples described below. To address this situation, the liquid discharge device 100 according to an embodiment of the present invention employs the following reference... Figures 22 to 26 The configuration described.

[0167] exist Figure 22 In the first example shown, the liquid discharge device 100 applies a driving voltage V1 to the head 11 at a discharge cycle q1 during the opening period Δ1 in the first time period T1. In the second time period T2, the liquid discharge device 100 applies a driving voltage V2 to the head 11 at a discharge cycle q2 during the opening period Δ2. Therefore, the liquid discharge device 100 in the first example differs from that in the example shown. Figure 21 The liquid discharge device 100 of the comparative example is depicted. Since the opening period Δ2 is shorter than the opening period Δ1, the amount of liquid discharged in the second period T2 is less than the amount of liquid discharged in the first period T1. As the liquid discharge device 100, as a first example, is executed... Figure 22 The discharge control shown is used to discharge from head 11. Figure 18 The depicted droplet is 80.

[0168] Figure 23 The liquid discharge device 100 depicted as a second example and Figure 22The difference in the liquid discharge device 100 depicted as a first example is that the discharge cycle q2 is shorter than the discharge cycle q1. With the liquid discharge device 100 as a second example performing... Figure 23 The discharge control shown is used to discharge from head 11. Figure 19 The depicted droplet is 80.

[0169] Figure 24 The liquid discharge device 100 described as a third example and Figure 23 The difference in the liquid discharge device 100 depicted as a second example is that the discharge cycle q2 gradually shortens as the head 11 moves. This is further illustrated by the liquid discharge device 100 as a third example. Figure 24 The discharge control shown is used to discharge from head 11. Figure 20 The depicted droplet is 80.

[0170] Figure 25 The liquid discharge device 100 depicted as a fourth example and Figure 21 The difference in the liquid discharge device 100 depicted as a comparative example is that the driving voltage V2 is lower than the driving voltage V1. With the liquid discharge device 100 as a fourth example performing... Figure 25 The discharge control shown is used to discharge from head 11. Figure 18 The depicted droplet is 80.

[0171] Figure 26 The liquid discharge device 100 depicted as the fifth example and Figure 21 The difference in the liquid discharge device 100 described as a comparative example is that the opening period Δ1 is equivalent to the first period T1, and the opening period Δ2 is equivalent to the second period T2. With the liquid discharge device 100 as a fifth example performing... Figure 26 The discharge control shown allows the head 11 to discharge a continuous stream of liquid instead of droplets, thereby creating a liquid filament.

[0172] Liquid discharge device 100 Figure 22 The first example depicted to Figure 26 The driving voltage used in any of the fifth examples depicted drives the head 11. The discharge control performed by the liquid discharge device 100 is not limited to the control of applying voltage to the head 11 to control the amount of movement of the valve 310 and the opening period of the valve 310. For example, the discharge control performed by the liquid discharge device 100 could be the control of air-driven valve 310 to control the amount of movement of valve 310 and the opening period of valve 310.

[0173] Because the discharge control of head 11 changes the amount of movement of valve 310 according to the length of the opening period of nozzle 311, the sound generated as valve 310 moves will vary. Therefore, if the amount of droplets 80 discharged by head 11 in tail region 121 is less than the amount of droplets 80 discharged in the outer region excluding tail region 121, the sound generated as valve 310 moves in tail region 121 will be different from the sound generated as valve 310 moves in the outer region excluding tail region 121. Therefore, in one respect, the sound generated as valve 310 moves can indicate that the amount of droplets 80 discharged by head 11 in tail region 121 is less than the amount of droplets 80 discharged in the outer region excluding tail region 121.

[0174] A description of the operation of the liquid discharge device 100 is provided. (Refer to...) Figure 27 The process for setting point data performed by the liquid discharge device 100 according to the first embodiment of the present invention is now described. Figure 27 This is a flowchart, as an example, of a process for setting point data performed by a liquid discharge device 100 according to a first embodiment of the present invention. Whenever the liquid discharge device 100 coats the object 200, before the liquid discharge device 100 begins coating, the liquid discharge device 100 performs... Figure 27 The process is shown.

[0175] In step S11, in order to monitor the movement of head 11 according to the shape of object 200, coating path generation unit 9031 of liquid discharge device 100 PC903 reads the coating path stored in a memory such as ROM of PC 903.

[0176] Subsequently, in step S12, the liquid discharge device 100 designates the tail region 121 of each discharge region 120 in the coating path read in step S11.

[0177] Subsequently, in step S13, the liquid discharge device 100 determines whether the tail region 121 of each discharge region 120 specified in step S12 overlaps with other discharge regions 120.

[0178] If the liquid discharge device 100 determines that the tail region 121 in each discharge region 120 does not overlap with other discharge regions 120 ("No" in step S13), the liquid discharge device 100 proceeds to step S15. In this case, the point data retains its default value. Conversely, if the liquid discharge device 100 determines that the tail region 121 in a particular discharge region 120 overlaps with other discharge regions 120 ("Yes" in step S13), the liquid discharge device 100 determines the following reference in step S14. Figure 28The parameters of the secondary droplet mitigation measures described are used to deal with secondary droplets. The liquid discharge device 100 changes the point data according to the parameters of the secondary droplet mitigation measures.

[0179] Subsequently, in step S15, the liquid discharge device 100 applies the point data to the coating path read in step S11.

[0180] As described above, the liquid discharge device 100 performs a process for setting point data.

[0181] Reference Figure 28 This document provides a description of a process performed by a liquid discharge device 100 according to a first embodiment of the present invention for determining parameters of secondary droplet mitigation measures. The parameters of the secondary droplet mitigation measures define parameters for various mitigation measures used to reduce the effects caused by secondary droplets. Figure 28 This is a flowchart, as an example, of a process performed by a liquid discharge device 100 according to a first embodiment of the present invention for determining parameters of a secondary droplet mitigation measure. The liquid discharge device 100 in... Figure 27 The described step S14 begins Figure 28 The process is described. The liquid discharge device 100 performs the process in the tail region 121 of each of the plurality of discharge regions 120. Figure 28 The process in each step described.

[0182] In step S21, the control unit 20 of the liquid discharge device 100 determines the span of the tail region 121 to which the secondary droplet mitigation measures are applied. For example, the liquid discharge device 100 determines a multiple of the diameter d of point 911, which specifies the span of the tail region 121 to which the secondary droplet mitigation measures are to be applied. This span is upstream of the rear end of the discharge region 120 in the first direction A of movement of the head 11. The determined multiple of the diameter d of point 911 is defined as n in the process described below.

[0183] Subsequently, in step S22, the control unit 20 of the liquid discharge device 100 determines the number of additional points to be added in order to perform the secondary droplet mitigation measures. The determined number of additional points is limited to m, which is limited by the relationship n ≤ m.

[0184] Subsequently, in step S23, the control unit 20 of the liquid discharge device 100 determines the amount of droplets 80 discharged onto the tail region 121, the amount being adjusted based on the drive voltage V2 and the opening time period Δ2.

[0185] Subsequently, in step S24, the control unit 20 of the liquid discharge device 100 determines the moving speed of the head 11 in the tail region 121.

[0186] Subsequently, in step S25, the control unit 20 of the liquid discharge device 100 determines the discharge cycle q2 in the tail region 121 based on the moving speed determined in step S24. The discharge cycle q2 can be constant or non-constant. However, the discharge cycle q2 defines the relationship q1 ≥ q2.

[0187] Subsequently, in step S26, based on the amount of droplets 80 discharged onto the tail region 121 determined in step S23, the control unit 20 of the liquid discharge device 100 determines the driving voltage for controlling the discharge from the head 11, for example, determining the driving voltage to use. Figures 22 to 26 Which of the driving voltages V1 and V2 in the first through fifth examples depicted?

[0188] As described above, the liquid discharge device 100 performs a process for determining parameters for secondary droplet mitigation measures.

[0189] Reference Figure 29 , Figure 30 , Figure 31A , Figure 31B , Figure 32 and Figure 33 This provides a description of the discharge of the head 11 of a liquid discharge device 100 according to a first embodiment of the present invention during reciprocating movement relative to an object 200. Figure 29 This is a schematic diagram illustrating, as an example, the reciprocating motion of the head 11 relative to the object 200 in a liquid discharge device 100 according to a first embodiment of the present invention. Figure 30 This is a first schematic diagram showing the discharge of a head 11 that reciprocates relative to an object 200 in a liquid discharge device 100 according to a first embodiment of the present invention. Figure 31A and Figure 31B Each of these is a second schematic diagram illustrating the discharge of a head 11 that reciprocates relative to an object 200 in a liquid discharge device 100 according to a first embodiment of the present invention. Figure 32 This is a third schematic diagram illustrating the discharge of a head 11 that reciprocates relative to an object 200 in a liquid discharge device 100 according to a first embodiment of the present invention. Figure 33 This is a fourth schematic diagram showing the discharge of a head 11 that reciprocates relative to an object 200 in a liquid discharge device 100 according to a first embodiment of the present invention.

[0190] Figure 29 , Figure 30 , Figure 31A , Figure 31B , Figure 32 and Figure 33Each of the figures shows the head 11 as viewed from above, moving relative to and across the object 200. A forward direction A1 defines one direction of the first direction A. A backward direction A2 defines a direction in the first direction A opposite to the forward direction A1. Figure 29 and Figure 30 The forward direction A1 is shown together with the reference numeral A for the first direction A to indicate that the first direction A includes the forward direction A1. Figure 29 , Figure 32 and Figure 33 The rearward direction A2 is shown together with the reference numeral A for the first direction A to indicate that the first direction A includes the rearward direction A2.

[0191] like Figure 29 As shown, the head 11 moves relative to the object 200 in the forward direction A1 to coat a first row of regions on the object 200. After the head 11 completes coating the first row of regions, it moves relative to the object 200 in a second direction B perpendicular to the first direction A to perform a feed. After the head 11 completes the feed, it moves relative to the object 200 in the rearward direction A2 to coat a second row of regions on the object 200. After the head 11 completes coating the second row of regions, it moves relative to the object 200 in the second direction B to perform a feed. After the head 11 completes the feed, it moves relative to the object 200 in the forward direction A1 to coat a third row of regions on the object 200. The head 11 of the liquid discharge device 100 moves relative to the object 200 as described above to discharge liquid.

[0192] Figure 30 yes Figure 29 An enlarged view of action 1 in the image. Figure 31A and Figure 31B Each of them is Figure 29 An enlarged view of action 2 in the diagram. (See attached image.) Figure 31A As shown, head 11 moves in the second direction B while maintaining its posture. Figure 31B As shown, for example, in action 2, the orientation of head 11 can be mirrored about an axis extending in the second direction B as a rotation axis. Figure 32 yes Figure 29 An enlarged view of action 3 in the video. Figure 33 yes Figure 29 A magnified view of action 4 in the video. Figure 30 , Figure 31A , Figure 31B , Figure 32 and Figure 33 In the example shown, the head 11 includes five nozzles 311 that discharge droplets.

[0193] For example, if the diameter dc of point 912 in tail region 121 is smaller than the diameter d of point 911 in the outer region excluding tail region 121, then the length in the second direction B defined by point 912 in tail region 121 is smaller than the length in the second direction B defined by point 911 in the outer region. Therefore, for example, areas where no droplets were applied may occur between the first row region and the second row region, i.e., printing defects. Printing defects may reduce the coating quality of the liquid discharge device 100.

[0194] Figure 1 The moving mechanism 13 of the depicted liquid discharge device 100 causes the head 11 to reciprocate relative to the object 200 in the forward direction A1 and the backward direction A2. Figure 30 As shown, in the tail region 121 in the forward direction A1, the diameter dc of point 912 is smaller than the diameter d of point 911 in the outer region of the discharge region 120 excluding the tail region 121. For example, the length of liquid falling on the tail region 121 in the forward direction A1 in the second direction B is less than the length of liquid falling on the outer region of the discharge region 120 in the forward direction A1 excluding the tail region 121 in the second direction B. Figure 32 As shown, the diameter de of point 913 in the upstream region of the front end region 122 of the discharge region 120, i.e., the upstream end region in the rearward direction A2, is greater than the diameter d of point 911 in the outer region of the discharge region 120 excluding the front end region 122. For example, the length of liquid in the upstream end region of the discharge region 120 in the rearward direction A2, where the head 11 discharges the liquid onto the object 200, in the second direction B is greater than the length of liquid in the outer region of the discharge region 120 excluding the upstream end region in the rearward direction A2, in the second direction B. For convenience, the upstream end region in the rearward direction A2 is described as the front end region 122. Figure 32 and Figure 33 As shown, the tail region 121 and the front region 122 are aligned in the first direction A.

[0195] Tail region 121 serves as a downstream region of discharge region 120 in the forward direction A1 or an upstream region of discharge region 120 in the backward direction A2. Front region 122 serves as a downstream region of discharge region 120 in the forward direction A1 or an upstream region of discharge region 120 in the backward direction A2. From another perspective, the configuration where tail region 121 and front region 122 are aligned in the first direction A is defined as follows: front region 122 includes tail region 121 in the first direction A. The alignment of tail region 121 and front region 122 in the first direction A is not limited to the following reversing positions in the reciprocating movement path: where head 11 changes its movement direction from forward direction A1 to backward direction A2; and where head 11 changes its movement direction from backward direction A2 to forward direction A1. The alignment of tail region 121 and front region 122 in the first direction A can be any position in the reciprocating movement path other than the reversing position.

[0196] The diameter de of point 913 in the front end region 122 in the rearward direction A2 of the discharge region 120 is greater than the diameter d of point 911 in the outer region of the discharge region 120 excluding the front end region 122. Therefore, the length of the front end region 122 in the second direction B increases. Since the front end region 122 is aligned with the tail end region 121 in the first direction A, the head 11 coats the uncoated areas on the object 200, i.e., the uncoated areas when the head 11 moves over the tail end region 121 on the object 200, and additionally, the uncoated areas when the head 11 moves over the front end region 122 on the object 200. As a result, the liquid discharge device 100 reduces printing defects. The reduction in printing defects suppresses the deterioration of the coating quality of the liquid discharge device 100.

[0197] exist Figure 32 In the depicted region XXXII, end point 914 partially overlaps with point 912 in the tail region 121. Figure 32 and Figure 33 In the example shown, the plurality of points 913 arranged in the second direction B in the front end region 122 include end points 914 and points 915 other than end points 914. End points 914 are located at the ends of the front end region 122 in the second direction B, adjacent to the tail end region 121. The diameter de of each end point 914 is greater than the diameter df of each point 915. Therefore, compared to a configuration where each of the plurality of points 913 has an increased diameter, the liquid discharge device 100 reduces the amount of droplets formed at points 915 other than end points 914, thereby saving droplets. Alternatively, the liquid discharge device 100 may be configured such that the diameter de of each of the plurality of points 913 arranged in the second direction B in the front end region 122 is greater than the diameter d of point 911.

[0198] exist Figure 33 In the example shown, the center-to-center distance pe between adjacent points 913 in the first direction A in the front end region 122 is greater than the center-to-center distance p between adjacent points 911 in the first direction A in the outer region of the discharge region 120 excluding the front end region 122. Therefore, the liquid discharge device 100 reduces the coating thickness difference between the front end region 122 and the outer region excluding the front end region 122. This difference may be caused by the amount of droplets forming at point 913 being greater than the amount of droplets forming at point 911. Therefore, the liquid discharge device 100 reduces coating thickness unevenness.

[0199] Reference Figures 34 to 36 It provides a description of the discharge areas of liquid discharge device 100 and liquid discharge device 100A. Figure 34 This is a view of object 200, showing the discharge area 120 of a liquid discharge device 100 according to a first embodiment of the present invention, as a first example. Figure 35 This is a view of object 200, showing the discharge area of ​​a liquid discharge device 100A according to a first embodiment of the present invention, as a second example. Figure 36 This is a view of object 200, showing the discharge area of ​​a liquid discharge device 100A according to a first embodiment of the present invention, as a third example.

[0200] exist Figure 34 In the liquid discharge device 100 depicted as a first example, a single head 11 reciprocates relative to the object 200 and discharges liquid into the discharge region 120, thereby coating the object 200. The tail region 121 defines the rear end of the discharge region 120 in the direction of reciprocating movement of the head 11 relative to the object 200.

[0201] Figure 35 The depiction serves as a second example and Figure 36 The liquid dispensing device 100A, depicted as a third example, includes a first head 11a that reciprocates relative to an object 200 and dispenses liquid into a first region 120a, thereby coating the object 200. The first region 120a includes a tail region 121a that defines a rear end of the first region 120a in the direction of reciprocating movement of the first head 11a relative to the object 200. The liquid dispensing device 100A also includes a second head 11b that reciprocates relative to the object 200 and dispenses liquid into a second region 120b, thereby coating the object 200. The second region 120b includes a tail region 121b that defines a rear end of the second region 120b in the direction of reciprocating movement of the second head 11b relative to the object 200.

[0202] exist Figure 35 In the second example shown, the first head 11a reciprocates relative to the object 200 to coat the first region 120a on the object 200. The second head 11b reciprocates relative to the object 200 to coat the second region 120b on the object 200.

[0203] exist Figure 36 In the third example shown, a first head 11a moves relative to the object 200 in a predetermined direction A3, thereby coating a first region 120a on the object 200. A second head 11b moves relative to the object 200 in a direction opposite to the predetermined direction A3, thereby coating a second region 120b on the object 200. At least a portion of the tail region 121a of the first region 120a in the predetermined direction A3 overlaps with the second region 120b. Because at least a portion of the tail region 121a of the first region 120a in the predetermined direction A3 overlaps with the second region 120b, the liquid discharge device 100A reduces contamination of the object 200 by secondary droplets while the first head 11a moves at a substantially constant speed and discharges droplets in a substantially constant amount.

[0204] A description of the structure of a liquid discharge device 100B according to a second embodiment of the present invention is provided. Elements having the same names and reference numerals as those according to the above embodiments denote the same or equivalent components or structures. Therefore, detailed descriptions of these elements are appropriately omitted. Detailed descriptions of these elements are similarly omitted in subsequent embodiments.

[0205] Reference Figure 37 This provides a description of the structure of the liquid discharge device 100B according to the second embodiment. Figure 37 This is a view of a liquid dispensing device 100B according to a second embodiment of the present invention, showing its structure as an example. The liquid dispensing device 100B includes a head 11A, which differs from the head 11 of the first embodiment in that the head 11A is fixed in place and applies coating to the moving object 200.

[0206] Figure 37The depicted liquid dispensing device 100B includes a moving mechanism 13 that holds the object 200 and moves it to a position near a stationary head 11A. Thereafter, the moving mechanism 13 moves the object 200 to a liquid dispensing position at the head 11A, where the head 11A coats the object 200. The liquid dispensing device 100B is preferably used for an object 200 that is sufficiently light or compact to be movable by the moving mechanism 13, etc. The liquid dispensing device 100B according to a second embodiment of the invention employs a liquid dispensing method similar to that employed by the liquid dispensing device 100 or 100A according to a first embodiment of the invention.

[0207] Reference Figure 38 and Figure 39 This document provides a description of the structure of a liquid discharge device 100C according to a third embodiment of the present invention. Figure 38 This is a view of a liquid discharge device 100C according to a third embodiment of the present invention, showing its structure as an example. Figure 39 It is a liquid discharge device 100C along Figure 38 A cross-sectional view taken from the XXXIX-XXXIX line.

[0208] The liquid discharge device 100C includes a head 11, a first guide 800, a fixed guide 810, and a second guide 820. The first guide 800 guides the head 11 and moves the head 11 in a first direction A. The fixed guide 810 combines the head 11 and the first guide 800 into a unit. The second guide 820 guides the head 11 and moves the head 11 in a second direction B perpendicular to the first direction A. The liquid discharge device 100C according to the third embodiment differs from the liquid discharge device 100 according to the first embodiment in that the head 11 is mounted on a component other than the moving mechanism 13.

[0209] like Figure 38 and Figure 39 As shown, the head 11 of the liquid dispensing device 100C is mounted on the first guide 800, allowing the head 11 to move in a first direction A. A fixing guide 810 combines the head 11 and the first guide 800 into a unit, allowing the head 11 and the first guide 800 to move along a second guide 820 in a second direction B. Therefore, the head 11 scans the object 200 in a two-dimensional direction along the first guide 800 and the second guide 820, thereby applying liquid to the object 200. The liquid dispensing device 100C according to the third embodiment of the present invention employs a liquid dispensing method similar to that employed by the liquid dispensing device 100 or 100A according to the first embodiment of the present invention.

[0210] The embodiments of the present invention have been described above. However, the technology of the present invention is not limited to the above embodiments. For example, various modifications and improvements can be made to the embodiments of the present invention within the scope of the present invention.

[0211] According to the embodiments described, the liquid discharged from the heads (e.g., heads 11 and 11A, first head 11a, and second head 11b) includes solutions, suspensions, emulsions, etc., which contain solvents such as water and organic solvents, colorants such as dyes and pigments, functional materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as deoxyribonucleic acid (DNA), amino acids, proteins, and calcium, and edible ingredients such as natural pigments. For example, the liquid is used as ink for inkjet printing, coating materials, surface treatment liquids, liquids for forming components of electronic components and light-emitting elements, liquids for forming resist patterns for electronic circuits, liquids for manufacturing three-dimensional objects, etc.

[0212] The functional units according to the above embodiments are implemented by one or more processing circuits. The processing circuits in this specification include processors programmed to execute the functional units using software, such as processors implemented by electronic circuits. The processing circuits also include devices designed to execute the above functional units, such as application-specific integrated circuits (ASICs), digital signal processors (DSPs), field-programmable gate arrays (FPGAs), and general-purpose circuit modules.

[0213] The technology of this invention is also applicable to coatings for purposes other than coloring and applying designs to the body of automobiles, etc. For example, a coating process for coating an automobile body includes: a primer process to ensure the adhesion, corrosion resistance, etc., of the coating film on the body substrate (e.g., the base layer of the body); a base coat process to ensure impact resistance, durability, etc.; and a top coat process for coloring and applying designs. The coating apparatus using the technology of this invention can be used not only in the top coat process but also in the primer or base coat process. If, after the top coat process, a coating process is performed to apply a protective layer, such as a clear layer, to increase gloss and protect the coating film, the coating apparatus using the technology of this invention can be used in the coating process to apply the protective layer. If, after the automobile leaves the factory or during the automobile manufacturing process, a peelable protective layer is applied to the coated surface to protect it, the coating apparatus using the technology of this invention can be used in the coating process to apply the protective layer. A peelable protective layer is attached to the coated surface of the vehicle body and protects the coated area from dust, metal powder, oil, salt, acid, ultraviolet light, etc., by chemical or physical means. For example, the protective layer is preferably formed of a material with acrylic copolymers as the main component.

[0214] The technology of this invention is also applicable to droplet ejection devices for purposes other than coating. For example, the technology of this invention is applicable to marking devices that eject droplets onto an object to mark specific locations on the object.

[0215] The following describes various aspects of embodiments of the present invention.

[0216] A first aspect of an embodiment of the invention is described. A liquid discharging device includes a head for discharging liquid onto an object and a moving mechanism for moving the head relative to the object. The head discharges liquid, which lands on the object. The moving mechanism moves the head relative to the object in a first direction perpendicular to a second direction. The head discharges the liquid into a discharging region on the object. The discharging region has a downstream end region in the first direction. The downstream end region is defined as a tail end region. The length of the liquid landing on the tail end region in the second direction is less than the length of the liquid landing on the regions of the discharging region other than the tail end region in the second direction.

[0217] A second aspect of embodiments of the invention is described below. In the liquid discharge device according to the first aspect, the relative movement speed of the head in the tail region is lower than the relative movement speed of the head in the discharge region excluding the tail region.

[0218] A third aspect of embodiments of the invention is described. In the liquid discharge device according to the first or second aspect, a first direction is defined as a forward direction. A direction opposite to the forward direction is defined as a rearward direction. A moving mechanism causes a head and an object to reciprocate relative to each other in the forward and rearward directions. The length of liquid falling on the tail region in the forward direction is less than the length of liquid falling on the region of the discharge area in the forward direction excluding the tail region in the second direction. The length of liquid falling on the upstream region in the rearward direction of the discharge area where the head discharges liquid onto the object is greater than the length of liquid falling on the region of the discharge area excluding the upstream region in the rearward direction, where the head discharges liquid onto the object. The position of the tail region in the forward direction is aligned with the position of the upstream region in the rearward direction in the first direction.

[0219] A fourth aspect of embodiments of the invention is described. In a liquid discharge device according to any one of the first to third aspects, a head discharges liquid, which falls onto an object to form a plurality of points.

[0220] A fifth aspect of embodiments of the invention is provided. In the liquid discharge device according to the fourth aspect, the center-to-center distance between adjacent points in the tail region in a first direction is less than the center-to-center distance between adjacent points in the first direction in the discharge region excluding the tail region.

[0221] A sixth aspect of embodiments of the invention is described. In a liquid discharge device according to a fourth or fifth aspect, a plurality of points are arranged in an upstream region in a second direction, and include an end point located at an end of the upstream region in the second direction. The end point is adjacent to a tail region. The diameter of the end point is larger than the diameter of the points other than the end point among the plurality of points.

[0222] A seventh aspect of embodiments of the invention is provided. In a liquid discharge device according to any one of the fourth to sixth aspects, the center-to-center distance between adjacent points in the upstream region in a first direction is greater than the center-to-center distance between adjacent points in the first direction in the discharge region other than the upstream region.

[0223] An eighth aspect of embodiments of the invention is described. A liquid discharge device according to any one of the first to seventh aspects includes a plurality of heads, the plurality of heads including a first head and a second head. The first head moves in a predetermined direction in a first direction to define a first region on an object. The second head moves in the first direction in a direction opposite to the predetermined direction to define a second region on the object. At least a portion of the tail region of the first region in the predetermined direction overlaps with the second region.

[0224] A ninth aspect of an embodiment of the invention is described. A liquid discharging device performs a liquid discharging method in which a head of the liquid discharging device discharges liquid onto an object. A moving mechanism moves the head and the object relative to each other in a first direction. The head discharges liquid, which falls onto the object. The moving mechanism moves the head relative to the object in a first direction perpendicular to a second direction. The head discharges liquid onto a discharging region on the object. The discharging region has a downstream end region in the first direction. The downstream end region is defined as a tail end region. The liquid falling onto the tail end region has a length in a second direction that is less than the length in a second direction of the liquid falling onto the regions of the discharging region other than the tail end region.

[0225] The above embodiments are exemplary and do not limit the invention. Therefore, many other modifications and variations can be made based on the above teachings. For example, within the scope of the invention, elements and / or features of different exemplary embodiments can be combined with and / or substituted for each other. Any of the above operations can be performed in various other ways, for example, in an order different from that described above.

[0226] This patent application is based on and claims priority to Japanese Patent Application No. 2024-041275, filed with the Japan Patent Office on March 15, 2024, the entire disclosure of which is hereby incorporated by reference.

[0227] List of reference numerals

[0228] 11: Head

[0229] 11-1, 11-2, 11-3, 11-4: Head

[0230] 11a: First head

[0231] 11b: Second head

[0232] 12, 12-1, 12-2, 12-3, 12-4: Detectors

[0233] 13, 13-1, 13-2, 13-3, 13-4: Moving mechanisms

[0234] 14: Supply Section

[0235] 20: Control Unit

[0236] 72: Driver

[0237] 80: Droplet

[0238] 81a, 81b: Main droplets

[0239] 82a, 82b: Liquid lines

[0240] 83a, 83b: Secondary droplets

[0241] 91, 91a, 91b: Points

[0242] 92, 92a, 92b: Satellite points

[0243] 911, 912, 913, 915: points

[0244] 914: Endpoint

[0245] 120: Discharge area

[0246] 120a: Zone 1

[0247] 120b: Second Zone

[0248] 121: Tail end area

[0249] 122: Front end area

[0250] 180: Coating

[0251] 800: First Guide

[0252] 810: Fixed guide

[0253] 820: Second Guide

[0254] 901: Controller

[0255] 9001: CPU

[0256] 9002: ROM

[0257] 9003: RAM

[0258] 9004: I / F

[0259] 9011: System Control Unit

[0260] 9012: Data storage unit

[0261] 9013: Memory Control Unit

[0262] 9014: Discharge periodic signal generation unit

[0263] 9015: Periodic Control Unit

[0264] 902: Head Control Unit

[0265] 903: PC

[0266] 9031: Coating Path Generation Unit

[0267] 9032: Coating Data Generation Unit

[0268] 9033: Exhaust frequency generation unit

[0269] 9034: Movement Speed ​​Generation Unit

[0270] 9035: RIP

[0271] 9036: Rendering Unit

[0272] 904: Mobility Control Unit

[0273] 905: Input device

[0274] 100: Liquid discharge device

[0275] 103: Head Unit

[0276] 109: Encoder Sensor

[0277] 110: Main Body

[0278] 111: Supply Port

[0279] 112: Collection Port

[0280] 200: Object

[0281] 201: Roof

[0282] 211, 211-1, 211-2, 211-3, 211-4: Coating area

[0283] 230: Compressor

[0284] 310: Valve

[0285] 311: Nozzle

[0286] 321: Nozzle plate

[0287] 322: Channel

[0288] 324: Piezoelectric element

[0289] 325: Liquid

[0290] 330: Liquid tank

[0291] 331: pipe

[0292] 332: Air conditioner

[0293] 333: Pipe

[0294] 340: Discharge Module

[0295] A: First direction

[0296] A1: Forward direction

[0297] A2: Backward direction

[0298] A3: Pre-determined direction

[0299] A4: Opposite direction

[0300] B: Second direction

[0301] C: Discharge direction

[0302] d, dc, de, df: diameter

[0303] p, pc, pe: Distance from center to center

[0304] L1, L2: Length

[0305] q1, q2: Period

[0306] t1, t2: Thickness

[0307] T1: First period

[0308] T2: Second period

[0309] T10, T1-1, T1-2, T1-3, T1-4: Relative movement paths

[0310] Δ1, Δ2: Opening period

[0311] V1, V2: Driving voltage

Claims

1. A liquid discharge device, comprising: The head is used to discharge liquid onto the object; and A moving mechanism for causing relative movement between the head and the object. The head discharges the liquid that has landed on the object. The moving mechanism moves the head relative to the object in a first direction perpendicular to the second direction. The head discharges the liquid onto a discharge area on the object, the discharge area having a downstream end region in the first direction, the downstream end region defining a tail end region. The liquid falling on the tail end region has a length in the second direction that is less than the length in the second direction of the liquid falling on the area of ​​the discharge region other than the tail end region.

2. The liquid discharge device according to claim 1, The relative movement speed of the head in the tail region is lower than the relative movement speed of the head in the discharge region other than the tail region.

3. The liquid discharge device according to claim 1 or 2, The first direction is defined as the forward direction. The direction opposite to the forward direction is defined as the backward direction. The moving mechanism causes the relative movement between the head and the object to reciprocate in the forward and backward directions. The length of the liquid falling on the tail end region in the forward direction in the second direction is less than the length of the liquid falling on the region of the discharge region other than the tail end region in the forward direction in the second direction. The length of liquid falling on the upstream end region in the rearward direction of the discharge region where the head discharges liquid onto the object in the second direction is greater than the length of liquid falling on the region in the second direction of the discharge region excluding the upstream end region in the rearward direction. The position of the tail end region in the forward direction is aligned with the position of the upstream end region in the rearward direction in the first direction.

4. The liquid discharge device according to any one of claims 1 to 3, The head discharges liquid that falls onto the object to form multiple points.

5. The liquid discharge device according to claim 4, The plurality of points includes points adjacent in the first direction, and The center-to-center distance between adjacent points in the tail region is less than the center-to-center distance between adjacent points in the discharge region other than the tail region.

6. The liquid discharge device according to claim 4 or 5, The plurality of points are arranged in the upstream region of the discharge region in the rearward direction, and include an end point located at the end of the upstream region in the second direction, the end point being adjacent to the tail region. The diameter of the end point is greater than the diameter of the points other than the end point among the plurality of points.

7. The liquid discharge device according to any one of claims 4 to 6, The plurality of points includes points adjacent in the first direction, and The center-to-center distance between adjacent points in the upstream region of the discharge region in the rearward direction is greater than the center-to-center distance between adjacent points in the region of the discharge region excluding the upstream region.

8. The liquid discharge device according to any one of claims 1 to 7, further comprising another head for discharging liquid onto the object, The head moves in a predetermined direction in the first direction to define a first region on the object. The other head moves in a direction opposite to a predetermined direction from the first direction to define a second region on the object, and At least a portion of the tail region of the first region in the predetermined direction overlaps with the second region.

9. A liquid discharge method performed by a liquid discharge device, the liquid discharge method comprising: The moving mechanism moves the head relative to the object in a first direction perpendicular to the second direction; The head discharges the liquid that has fallen onto the object; The head discharges liquid into a discharge region on the object, the discharge region having a downstream end region in the first direction, the downstream end region defining a tail end region; and The length of the liquid falling on the tail end region in the second direction is less than the length of the liquid falling on the discharge region other than the tail end region in the second direction.

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