Coating device

Abstract

To suppress curing of liquid in piping connected to a port of a head.SOLUTION: A coating device 10 comprises a supply tank 11 that stores liquid L, a head 12 having a discharge unit 21 that discharges the liquid L onto a workpiece W, and a flow path section 13 having piping for supplying the liquid L from the supply tank 11 to the head 12. The head 12 has a first port 31 through which the liquid L can pass and a second port 32 through which the liquid L can pass. For a coating operation of discharging the liquid L from the discharge unit 21 and applying the liquid L to the workpiece W, a first supply state in which the supply tank 11 and the head 12 are connected through the first port 31 to supply the liquid L to the head 12, and a second supply state in which the supply tank 11 and the head 12 are connected through the second port 32 to supply the liquid L to the head 12 can be alternatively switched.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a coating apparatus.

Background Art

[0002] In order to discharge a liquid onto a workpiece such as glass or a film and form films (film patterns) of various shapes on the workpiece, for example, a coating apparatus disclosed in Patent Document 1 is used. The coating apparatus includes a supply tank for storing the liquid, a head having a nozzle (discharge portion) for discharging the liquid, and a flow path portion having a pipe for supplying the liquid from the supply tank to the head.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the coating apparatus as described above, for example, gas (air) may be mixed into the liquid in the head. If a large amount of gas is contained in the liquid, it may not be possible to correctly discharge the liquid from the nozzle. Therefore, before the coating operation of discharging the liquid onto the workpiece, a discharging operation is performed to discharge the liquid filled in the head and the pipe connected to the head to a waste liquid tank.

[0005] That is, the gas present in the liquid is forcibly discharged from the head together with the liquid, and the liquid is finally sent to a waste liquid tank. Thereby, the gas mixed into the liquid in the head and the pipe connected to the head is removed. FIG. 6 is an explanatory diagram of a discharging operation by a conventional coating apparatus. The head 90 has a supply port 91 and a discharge port 99 in addition to a nozzle 95 for discharging the liquid onto the workpiece W.

[0006] Before the coating operation, startup preparation is performed. In the startup preparation, the first valve 93 of the supply pipe 92 connected to the supply port 91 and the second valve 97 of the discharge pipe 98 connected to the discharge port 99 are both opened. Liquid is supplied from a supply tank (not shown) to the head 90 through the supply port 91, and the liquid that has passed through the head 90 is discharged to a waste liquid tank (not shown) through the discharge port 99. Thereby, the gas of the liquid in the head 90 and the like is discharged.

[0007] Thereafter, as shown in FIG. 7, the second valve 97 is closed, and the coating operation is started. FIG. 7 is an explanatory diagram of the coating operation by a conventional coating apparatus. During the coating operation, the liquid existing in the flow path (a part of the discharge pipe 98) from the discharge port 99 to the second valve 97 is in a state of staying. If the state of staying of the liquid continues for a long time, it deteriorates and hardens. Then, when the next discharge operation is performed, there is a possibility that the liquid cannot be discharged from the head 90 through the discharge port 99. In particular, when the liquid has a property of being easily cured like UV ink, such a problem is likely to occur.

[0008] Therefore, an object of the present disclosure is to provide a coating apparatus capable of suppressing the hardening of the liquid in the pipe connected to the port of the head.

Means for Solving the Problems

[0009] The coating apparatus of the present invention includes a supply tank for storing a liquid, a head having a discharge part for discharging the liquid to a work, and a flow path part having a pipe for supplying the liquid from the supply tank to the head. The head has a first port through which the liquid can pass and a second port through which the liquid can pass. For the coating operation of discharging the liquid from the discharge part and applying the liquid to the work, the supply tank and the head are connected through the first port to supply the liquid to the head in a first supply state, and the supply tank and the head are connected through the second port to supply the liquid to the head in a second supply state, and can be selectively switched.

Effects of the Invention

[0010] According to the coating apparatus of the present invention, it is possible to suppress the hardening of the liquid in the pipe connected to the port of the head.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0012] <Summary of Embodiments of the Present Invention> Hereinafter, the summary of the embodiments of the present invention will be listed and described. (1) The coating apparatus of the present invention includes a supply tank for storing a liquid, a head having a discharge unit for discharging the liquid onto a workpiece, and a flow path unit having a pipe for supplying the liquid from the supply tank to the head. The head has a first port through which the liquid can pass and a second port through which the liquid can pass. For the coating operation of discharging the liquid from the discharge unit and applying the liquid to the workpiece, the supply tank and the head are connected through the first port to supply the liquid to the head in a first supply state, and the supply tank and the head are connected through the second port to supply the liquid to the head in a second supply state, and the two states can be selectively switched.

[0013] According to the coating device, for the coating operation, the first supply state and the second supply state are switched at a predetermined timing, so that an opportunity for the liquid to flow occurs in both the first port and the second port. Therefore, hardening of the liquid in the pipes connected to the first port and the second port respectively can be suppressed.

[0014] (2) In the coating device of (1) above, it has a waste liquid section for receiving the liquid discharged from the head through the first port or the second port. According to the above configuration, it is possible to perform a discharging operation of flowing the liquid from the head to the waste liquid section to discharge the gas contained in the liquid of the head. As described above, since hardening of the liquid in the pipes connected to the first port and the second port respectively can be suppressed, the discharging operation is surely performed.

[0015] (3) In the coating device of (1) or (2) above, the flow path section includes a first pipe connecting the first port and the supply tank, a second pipe connecting to the second port, a bypass pipe connecting the first pipe and the second pipe, and a valve whose opening / closing state is switched to flow the liquid in the supply tank to the head through either one of the first port and the second port. According to the above configuration, the liquid in the supply tank is supplied to the head through the first port by flowing through the first pipe (first supply state). From the first supply state, by switching the opening / closing state of the valve, the liquid in the supply tank is supplied to the head through the second port via the bypass pipe in the middle (second supply state).

[0016] (4) The coating device of (2) above can alternatively switch between a first discharge state in which the first port and the waste liquid section are connected through the pipe in the flow path section to discharge the liquid of the head to the waste liquid section, and a second discharge state in which the second port and the waste liquid section are connected through the pipe in the flow path section to discharge the liquid of the head to the waste liquid section, for the discharging operation of flowing the liquid from the head to the waste liquid section to discharge the gas contained in the liquid of the head. According to the above configuration, for the discharging operation, the first discharging state and the second discharging state are switched at a predetermined timing, so that opportunities for liquid to flow occur in both the first port and the second port. Therefore, hardening of the liquid in the pipes connected to the first port and the second port respectively can be suppressed.

[0017] (5) In the coating device of (4) above, the flow path section includes a first pipe connecting the first port and the supply tank, a second pipe connecting the second port and the waste liquid section, a bypass pipe connecting the first pipe and the second pipe, and a valve whose opening and closing state is switched in order to flow the liquid of the head to the waste liquid section through either one of the first port and the second port. According to the above configuration, the liquid of the head flows through the first port, passes through the bypass pipe in the middle, and is discharged to the waste liquid section (first discharging state). By switching the opening and closing state of the valve from the first discharging state, the liquid of the head flows through the second pipe through the second port and is discharged to the waste liquid section (second discharging state).

[0018] (6) The coating device of (4) or (5) above switches from one of the first discharging state and the second discharging state to the other during the discharging operation. According to the above configuration, for example, even if gas is difficult to escape in the first discharging state, when the second discharging state is reached, it may be possible to expect the discharge of the gas that was difficult to escape. The performance of discharging gas from the head is enhanced.

[0019] <Details of Embodiments of the Present Invention> Hereinafter, details of embodiments of the present invention will be described. 〔Overall Configuration of Coating Device〕 FIG. 1 is a configuration diagram showing an example of the coating apparatus of the present invention. The coating apparatus 10 is an apparatus for applying a liquid to a workpiece W such as glass or a film. The coating apparatus 10 shown in FIG. 1 is an inkjet coating apparatus, which discharges a liquid onto the surface of the workpiece W by an inkjet method to form films (film patterns) of various shapes such as a line segment or a rectangle. The liquid used in the coating apparatus 10 is not limited, but the liquid described in this embodiment is a coating liquid having a property of easily curing over time, such as UV ink.

[0020] The coating apparatus 10 includes a supply tank 11 for storing the liquid L, a head (inkjet head) 12, a flow path section 13, and a waste liquid section 17. The coating apparatus 10 further includes a stage 14 for placing and holding the workpiece W, a transfer device 15 for relatively moving the head 12 and the workpiece W, and a control device 16.

[0021] The workpiece W may be a single-sheet substrate or a continuous sheet. Hereinafter, the case where the workpiece W is a single-sheet substrate will be mainly described. The supply tank 11 stores an amount of the liquid L required for production. That is, the supply tank 11 stores an amount of the liquid L that enables coating of a plurality of workpieces W.

[0022] The head 12 has a discharge section 21 for discharging the liquid L onto the workpiece W. In the case of this embodiment, the discharge section 21 has a plurality of nozzles 212 (inkjet nozzles). The nozzles 212 open on the lower surface of the head 12. Inside the head 12, the pressure of the liquid L applied to the nozzles 212 is maintained below atmospheric pressure. Thereby, the liquid L is held in the nozzles 212. A drive element (piezo element) is provided in the nozzles 212. When a drive voltage is applied to the drive element, the nozzles 212 discharge the liquid L as droplets.

[0023] The head 12 has a first port 31 through which the liquid L can pass and a second port 32 through which the liquid L can pass. The head 12 has an internal flow path 22 inside thereof. The internal flow path 22 is a flow path provided along the longitudinal direction of the head 12. The liquid in the internal flow path 22 is supplied to each nozzle 212. One longitudinal direction of the internal flow path 22 is connected to the first port 31, and the other longitudinal direction of the internal flow path 22 is connected to the second port 32.

[0024] A first pipe 51 included in the flow path section 13 is connected to the first port 31. A second pipe 52 included in the flow path section 13 is connected to the second port 32. In the case of the form shown in FIG. 1, the first pipe 51 is a pipe from the supply tank 11 to the first port 31. The second pipe 52 is a pipe from the second port 32 to the waste liquid section 17.

[0025] As will be described later, the first port 31 allows the liquid L supplied from the supply tank 11 to pass through and also allows the liquid L to pass through for discharging the liquid L from the head 12. That is, the first port 31 may function as a supply port for supplying the liquid L to the head 12 and may function as a discharge port for discharging the liquid L from the head 12. The second port 32 allows the liquid L supplied from the supply tank 11 to pass through and also allows the liquid L to pass through for discharging the liquid L from the head 12. That is, the second port 32 may function as a supply port for supplying the liquid L to the head 12 and may function as a discharge port for discharging the liquid L from the head 12.

[0026] The application operation of the liquid L by the head 12 will be described. During the coating operation, the transfer device 15 moves the stage 14, which holds the workpiece W, relative to the head 12. Alternatively, during the coating operation, the transfer device 15 moves the head 12 relative to the stage 14, which holds the workpiece W. That is, the transfer device 15 relatively moves the workpiece W (stage 14) and the head 12. During this movement, the liquid L is discharged from the discharge portion 21 of the head 12, and the liquid L is applied to the workpiece W. Thus, the operation of discharging the liquid L from the discharge portion 21 and applying the liquid L to the workpiece W is referred to as the "coating operation".

[0027] The control device 16 is composed of a computer. The control device 16 executes control for the coating operation and the discharge operation described later. Specifically, the control device 16 controls the operation of the transfer device 15, the discharge of the liquid L by the discharge portion 21 (nozzle 212) of the head 12, and the opening and closing operations of the respective valves (71 to 75) of the flow path portion 13.

[0028] The waste liquid portion 17 receives the liquid L discharged from the head 12. The waste liquid portion 17 of the present embodiment is a waste liquid tank. Hereinafter, the waste liquid portion 17 will be described as the waste liquid tank 17. Gas (air) may be mixed into the liquid L in the head 12. If a large amount of gas is contained in the liquid L, it may not be possible to correctly discharge the liquid L from the nozzle 212 during the coating operation. Therefore, before the coating operation, it is necessary to discharge a part of the liquid L filled in the head 12 and the liquid L filled in the pipe connected to the head 12 to the waste liquid tank 17. Thus, the operation of flowing the liquid L from the head 12 to the waste liquid tank 17 to discharge the gas contained in the liquid L of the head 12 is referred to as the "discharge operation".

[0029] The flow path portion 13 has a plurality of pipes for supplying the liquid L from the supply tank 11 to the head 12. These pipes also function as pipes for flowing the liquid L from the head 12 to the waste liquid tank 17. The supply tank 11 and the head 12 are connected by the pipes of the flow path section 13, and the head 12 and the waste liquid tank 17 are connected by the pipes of the flow path section 13. Each pipe of the flow path section 13 may be made of resin or metal.

[0030] 〔Regarding the piping structure〕 The piping structure of the flow path section 13 of the present embodiment will be described. In addition to the first pipe 51 and the second pipe 52, the flow path section 13 has a bypass pipe. In the case of the present embodiment, the bypass pipe includes a first bypass pipe 53 and a second bypass pipe 54. The first pipe 51 has a first branch section (first branch pipe) 61 on the supply tank 11 side and a second branch section (second branch pipe) 62 on the head 12 side. The second pipe 52 has a third branch section (third branch pipe) 63 on the head 12 side and a fourth branch section (fourth branch pipe) 64 on the waste liquid tank 17 side.

[0031] The first bypass pipe 53 is a pipe connecting the first branch section 61 and the third branch section 63. The second bypass pipe 54 is a pipe connecting the second branch section 62 and the fourth branch section 64. The flow path section 13 has a first valve 71, a second valve 72, a third valve 73, a fourth valve 74, and a fifth valve 75. These valves (71 to 75) are electromagnetic on-off valves and can be switched between an open state and a closed state. The control of the opening and closing operations of the valves (71 to 75) is performed by the control device 16.

[0032] The first valve 71 is provided in the first bypass pipe 53. The second valve 72 is provided between the first branch section 61 and the second branch section 62. The third valve 73 is provided in the second bypass pipe 54. The fourth valve 74 is provided between the third branch section 63 and the fourth branch section 64. The fifth valve 75 is provided between the fourth branch section 64 and the waste liquid tank 17.

[0033] 〔Regarding the coating operation〕 The coating operation performed by the coating apparatus 10 having the above configuration will be described. FIG. 2 is an explanatory diagram showing the case where the coating apparatus 10 is in the first supply state, and FIG. 3 is an explanatory diagram showing the case where the coating apparatus 10 is in the second supply state. The coating apparatus 10 can alternatively switch between the first supply state and the second supply state.

[0034] The first supply state is a state in which the supply tank 11 and the head 12 are connected through the first port 31, and the liquid L in the supply tank 11 is supplied to the head 12. That is, the first valve 71 is in the closed state, the second valve 72 is in the open state, the liquid L in the supply tank 11 flows through the first pipe 51, and is supplied from the first port 31 to the head 12. The liquid L in the supply tank 11 is not supplied to the head 12 through the second port 32.

[0035] In the first supply state, the first valve 71, the third valve 73, and the fourth valve 74 are in the closed state. The liquid L in the head 12 is in a state where it cannot pass through the second port 32. Therefore, the liquid L in the head 12 cannot be discharged through the second port 32. The liquid L supplied to the head 12 through the first port 31 can be discharged from the discharge part 21, and the coating operation is performed. During the coating operation, the fifth valve 75 is in the closed state whether it is in the first supply state or the second supply state.

[0036] The second supply state is a state in which the supply tank 11 and the head 12 are connected through the second port 32, and the liquid L in the supply tank 11 is supplied to the head 12. That is, the first valve 71 is in the open state, the second valve 72 is in the closed state, and the liquid L in the supply tank 11 flows through the portion of the first pipe 51 up to the first branch part 61, the first bypass pipe 53, and the portion on the head 12 side from the third branch part 63 of the second pipe 52, and is supplied from the second port 32 to the head 12. The liquid L in the supply tank 11 is not supplied to the head 12 through the first port 31.

[0037] In the second supply state, the second valve 72, the third valve 73, and the fourth valve 74 are in the closed state. The liquid L in the head 12 is in a state where it cannot pass through the first port 31. Therefore, the liquid L in the head 12 cannot be discharged through the first port 31. The liquid L supplied to the head 12 through the second port 32 can be discharged from the discharge part 21, and the coating operation is performed.

[0038] Thus, in the case of this embodiment, the flow path part 13 has a first pipe 51 connecting the first port 31 and the supply tank 11, a second pipe 52 connected to the second port 32, and a first bypass pipe 53 and a second bypass pipe 54 connecting the first pipe 51 and the second pipe 52. Furthermore, the flow path part 13 has a plurality of valves (71 to 75) whose open / closed states can be switched, and flows the liquid L in the supply tank 11 to the head 12 by switching the ports of the head 12. That is, the flow path part has a plurality of valves (71 to 75) whose open / closed states can be switched in order to flow the liquid L in the supply tank 11 to the head 12 through either one of the first port 31 and the second port 32.

[0039] The change of the supply state by switching the valves will be further described. As shown in FIG. 2, when the first valve 71 is closed and the second valve 72 is open, the liquid L in the supply tank 11 is supplied to the head 12 through the first pipe 51 and the first port 31 (first supply state). From the first supply state shown in FIG. 2, as shown in FIG. 3, the open / closed states of the valves (71 to 75) are switched.

[0040] Thereby, the liquid L in the supply tank 11 is supplied to the head 12 through the first bypass pipe 53 on the way and through the second port 32 (second supply state). That is, when the first valve 71 is open and the second valve 72 is closed, the liquid L in the supply tank 11 reaches the middle part of the first pipe 51 (first branch part 61), and through the first bypass pipe 53, the second pipe 52 (however, from the third branch part 63), and the second port 32, it is supplied to the head 12 (second supply state).

[0041] For the coating operation, the first supply state and the second supply state are switched at a predetermined timing (first timing). By this switching, an opportunity for the liquid L to flow occurs in both the pipe connected to the first port 31 (the pipe on the head 12 side of the first pipe 51) and the pipe connected to the second port 32 (the pipe on the head 12 side of the second pipe 52). Therefore, hardening of the liquid L in the pipes connected to the first port 31 and the second port 32 respectively is suppressed.

[0042] An example of the "predetermined timing (first timing)" will be described. When the work W is a single-sheet substrate, the predetermined timing is, for example, for each coating operation of one work W. That is, every time the work W to be coated is replaced, the coating apparatus 10 is switched between the first supply state and the second supply state. Alternatively, the predetermined timing may be for each coating operation of a plurality (predetermined number) of works W. Alternatively, the predetermined timing may be for each predetermined time, such as every hour, every day, or every week. Note that the interval for switching from the first supply state to the second state and the interval for switching from the second supply state to the first state, that is, the predetermined timing, is preferably short. Therefore, it is preferable that the state is switched for each sheet of the work W.

[0043] Note that when the work W is a continuous sheet, although not shown, the sheet is wound around a roll, and the coating apparatus 10 performs a coating operation on the sheet fed out from the roll. Therefore, the predetermined timing may be every time the roll is replaced. Or it may be the same as when the work W is a single sheet. That is, even when the work W is a continuous sheet, since the coating operation is intermittently executed, the predetermined timing may be, for example, for each coating operation.

[0044] 〔Regarding the discharging operation〕 The discharging operation performed by the coating apparatus 10 having the above configuration will be described. FIG. 4 is an explanatory view showing the case where the coating apparatus 10 is in the first discharging state, and FIG. 5 is an explanatory view showing the case where the coating apparatus 10 is in the second discharging state. The coating device 10 can alternatively switch between a first discharge state and a second discharge state. As described above, the coating device 10 has a waste liquid tank (waste liquid section) 17. The waste liquid tank 17 receives the liquid L discharged from the head 12 through the first port 31 or the second port 32.

[0045] The first discharge state is a state in which the first port 31 and the waste liquid tank 17 are connected through the piping of the flow path section 13, and the liquid L in the head 12 is discharged to the waste liquid tank 17. That is, the second valve 72 and the fourth valve 74 are in a closed state, the first valve 71, the third valve 73, and the fifth valve 75 are in an open state, and the liquid L in the supply tank 11 flows through the portion of the first pipe 51 up to the first branch section 61, the first bypass pipe 53, and the portion on the head 12 side from the third branch section 63 of the second pipe 52, and is supplied to the head 12 from the second port 32.

[0046] The liquid L supplied to the head 12 passes through the internal flow path 22 of the head 12 and is discharged from the first port 31. Further, it flows through the portion of the first pipe 51 up to the second branch section 62, the second bypass pipe 54, and the second pipe 52 (the portion from the fourth branch section 64), and is sent to the waste liquid tank 17.

[0047] The second discharge state is a state in which the second port 32 and the waste liquid tank 17 are connected through the piping of the flow path section 13, and the liquid L in the head 12 is discharged to the waste liquid tank 17. That is, the second valve 72, the fourth valve 74, and the fifth valve 75 are in an open state, the first valve 71 and the third valve 73 are in a closed state, and the liquid L in the supply tank 11 flows through the first pipe 51 and is supplied to the head 12 from the first port 31. The liquid L supplied to the head 12 passes through the internal flow path 22 of the head 12, is discharged from the second port 32, flows through the second pipe 52, and is sent to the waste liquid tank 17.

[0048] In this way, in either the first discharge state or the second discharge state, the liquid L can be flowed from the head 12 to the waste liquid tank 17 to discharge the gas contained in the liquid L of the head 12.

[0049] From the above, in the case of this embodiment, the flow path section 13 includes a first pipe 51 connecting the first port 31 and the supply tank 11, a second pipe 52 connecting the second port 32 and the waste liquid tank 17, and a bypass pipe connecting the first pipe 51 and the second pipe 52. The flow path section 13 of this embodiment has a first bypass pipe 53 and a second bypass pipe 54 as the bypass pipe. Furthermore, the flow path section 13 has a plurality of valves (71 to 75) whose opening and closing states can be switched, and the liquid L of the head 12 is made to flow to the waste liquid tank 17 by switching the ports of the head 12. That is, the flow path section 13 has valves (71 to 75) whose opening and closing states can be switched in order to make the liquid L of the head 12 flow to the waste liquid tank 17 through either one of the first port 31 and the second port 32.

[0050] The change in the discharge state due to the switching of the valves will be further described. As shown in FIG. 4, when the first valve 71, the third valve 73, and the fifth valve 75 are open and the second valve 72 and the fourth valve 74 are closed, the liquid L in the supply tank 11 reaches the middle part of the first pipe 51 (the first branch part 61), and is supplied to the head 12 through the first bypass pipe 53 and the second pipe 52 (however, from the third branch part 63). Further, the liquid L is discharged from the first port 31 through the internal flow path 22 of the head 12, and is discharged to the waste liquid tank 17 through the first pipe 51 (up to the second branch part 62) and the second bypass pipe 54 (the first discharge state).

[0051] From the first discharge state shown in Fig. 4, as shown in Fig. 5, the opening and closing states of the valves (71 - 75) are switched. That is, with the first valve 71 and the third valve 73 closed and the second valve 72, the fourth valve 74, and the fifth valve 75 open, the liquid L in the supply tank 11 is supplied to the head 12 through the first pipe 51 and the first port 31. The liquid L is discharged from the second port 32 through the internal flow path 22 of the head 12. The liquid L discharged from the second port 32 is discharged into the waste liquid tank 17 through the second pipe 52 (second discharge state).

[0052] For the discharging operation, the first discharge state and the second discharge state are switched at a predetermined timing (second timing). By this switching, opportunities for the liquid L to flow occur in both the pipe connected to the first port 31 (the pipe on the head 12 side of the first pipe 51) and the pipe connected to the second port 32 (the pipe on the head 12 side of the second pipe 52). Therefore, hardening of the liquid L in the pipes connected to the first port 31 and the second port 32 respectively is suppressed.

[0053] An example of the "predetermined timing (second timing)" will be described. The second timing for switching the state in the discharging operation is different from the first timing for switching the state in the coating operation. That is, in the discharging operation, during the series of discharging operations, it is switched from one of the first discharge state and the second discharge state to the other. The discharging operation is executed before the coating operation, and during this discharging operation, it is switched from one of the first discharge state and the second discharge state to the other.

[0054] By performing the switching in this way, for example, in the first discharge state, even if it is difficult for gas to escape inside the head 12, when switched to the second discharge state, it may be possible to expect the discharge of the gas that was difficult to escape. That is, the performance of discharging gas from the head 12 is enhanced. In addition, the switching between the first discharge state and the second discharge state may be performed for each discharge operation, other than during the discharge operation. That is, the first discharge operation performed first as a series may be in the first discharge state, and then the coating operation is executed, and the subsequent discharge operation may be in the second discharge state.

[0055] 〔Regarding the discharge operation and the coating operation〕 As described above, the discharge operation is executed before the coating operation. In one discharge operation, first, when the first discharge state shown in FIG. 4 is set and then switched to the second discharge state shown in FIG. 5, the coating operation performed subsequent to that discharge operation (FIG. 5) is performed in the first supply state shown in FIG. 2. In this case, in order to change the operation from the second discharge state (FIG. 5) to the first supply state (FIG. 2), the valves for changing the opening / closing state (changing from open to closed), the fourth valve 74 and the fifth valve 75, are sufficient.

[0056] Furthermore, the discharge operation performed after that coating operation (FIG. 2) starts from the second discharge state (FIG. 5) and is switched to the first discharge state (FIG. 4) midway. In this way, in order to start the discharge operation performed after the coating operation in the first supply state (FIG. 2) from the second discharge state (FIG. 5), the valves for changing the opening / closing state (changing from closed to open), the fourth valve 74 and the fifth valve 75, are sufficient.

[0057] Another pattern will be described. In one discharge operation, first, when the second discharge state shown in FIG. 5 is set and then switched to the first discharge state shown in FIG. 4, the coating operation performed subsequent to that discharge operation (FIG. 4) is performed in the second supply state shown in FIG. 3. In this case, in order to change the operation from the first discharge state (FIG. 4) to the second supply state (FIG. 3), the valves for changing the opening / closing state (changing from open to closed), the third valve 73 and the fifth valve 75, are sufficient.

[0058] Furthermore, the discharging operation performed after the coating operation (Fig. 3) is started from the first discharging state (Fig. 4) and switched to the second discharging state (Fig. 5) midway. Thus, in order to start the discharging operation performed after the coating operation in the second supply state (Fig. 3) from the first discharging state (Fig. 4), the valves for changing the opening / closing state (changing from closed to open), namely, the third valve 73 and the fifth valve 75, are sufficient.

[0059] 〔Regarding the coating apparatus 10 of the present embodiment〕 During the coating operation in the first supply state (Fig. 2), it is conceivable that the liquid L stays without flowing in the pipe on the second port 32 side. If the liquid L stays for a long time, the liquid L hardens. Then, when the liquid L is discharged to the waste liquid tank 17 after the coating operation through the second port 32, the discharge may become difficult. However, the coating apparatus 10 of the present embodiment can be switched from the first supply state (Fig. 2) to the second supply state (Fig. 3) at a predetermined timing (the first timing). The liquid L passes through the second port 32. Therefore, the hardening of the liquid L on the second port 32 side is suppressed.

[0060] Similarly, during the coating operation in the second supply state (Fig. 3) of the coating apparatus 10, it is conceivable that the liquid L stays without flowing in the pipe on the first port 31 side. If the liquid L stays for a long time, the liquid L hardens. Then, when the liquid L is discharged to the waste liquid tank 17 after the coating operation through the first port 31, the discharge may become difficult. However, the coating apparatus 10 of the present embodiment can be switched from the second supply state (Fig. 3) to the first supply state (Fig. 2) at a predetermined timing (the first timing). The liquid L passes through the first port 31. Therefore, the hardening of the liquid L on the first port 31 side is suppressed.

[0061] Furthermore, in the coating apparatus 10 of the present embodiment, a discharging operation is performed. In the discharging operation, a first discharging state (FIG. 4) in which the first port 31 and the waste liquid tank 17 are connected through the piping of the flow path section 13 to discharge the liquid L in the head 12 to the waste liquid tank 17, and a second discharging state (FIG. 5) in which the second port 32 and the waste liquid tank 17 are connected through the piping of the flow path section 13 to discharge the liquid L in the head 12 to the waste liquid tank 17 are alternatively switched.

[0062] For the discharging operation, by switching between the first discharging state and the second discharging state at a predetermined timing (the second timing), an opportunity for the liquid L to flow occurs in both the first port 31 and the second port 32. Therefore, hardening of the liquid in the piping connected to each of the first port 31 and the second port 32 is suppressed.

[0063] 〔Others〕 The piping structure of the flow path section 13 may be other than the illustrated structure. In the coating apparatus 10 of the above embodiment, the first pipe 51 is directly connected to the supply tank 11, and the second pipe 52 is not directly connected to the supply tank 11 but is indirectly connected to the supply tank 11 via the bypass pipes 53 and 54.

[0064] In addition to this, for the coating operation, since the first supply state and the second supply state are alternatively switched, the flow path section 13 may have another configuration. For example, although not shown, a first pipe 51 connected to the first port 31 is directly connected to the supply tank 11, and a second pipe 52 connected to the second port 32 is directly connected to the supply tank 11, and when supplying the liquid L to the head 12, a configuration in which the first pipe 51 (first port 31) and the second pipe 52 (second port 32) are alternatively used may be adopted. That is, a configuration in which two pipes are independently connected to the supply tank 11, one is connected to the first port 31, and the other is connected to the second port 32 may also be adopted.

[0065] Although the coating apparatus 10 of this embodiment has been described as having an inkjet head 12, the coating apparatus 10 may have a head 12 of other types.

[0066] As the invention of the present disclosure, the coating apparatus 10 focusing on the discharging operation is as follows. The coating apparatus 10 has a supply tank 11 for storing the liquid L, a head 12 having a discharge part 21 (nozzle 212) for discharging the liquid L to the work W, a flow path part 13 having a pipe for supplying the liquid L from the supply tank 11 to the head 12, and the head 12 has a first port 31 through which the liquid L can pass, a second port 32 through which the liquid L can pass, and has a waste liquid part (waste liquid tank) 17 for receiving the liquid L discharged from the head 12 through the first port 31 or the second port 32, For the discharging operation of flowing the liquid L from the head 12 to the waste liquid part 17 to discharge the gas contained in the liquid L of the head 12, a first discharge state in which the first port 31 and the waste liquid part 17 are connected through the pipe of the flow path part 13 to discharge the liquid L of the head 12 to the waste liquid part 17, a second discharge state in which the second port 32 and the waste liquid part 17 are connected through the pipe of the flow path part 13 to discharge the liquid L of the head 12 to the waste liquid part 17, can be selectively switched.

[0067] For the coating apparatus 10 focusing on such a discharging operation, each configuration of the coating apparatus 10 according to the above-described embodiment shown in FIGS. 1 to 5 can be adopted.

[0068] All the embodiments disclosed this time are illustrative in all respects and not restrictive. The technical scope of the present invention is not limited to the above-described embodiments, and this technical scope includes all modifications within the scope equivalent to the configurations described in the claims.

Description of Symbols

[0069] 10 Coating device 11 Supply tank 12 Head 13 Flow path section 17 Waste liquid tank (waste liquid section) 21 Discharge section 31 First port 32 Second port 51 First pipe 52 Second pipe 53 First bypass pipe (bypass pipe) 54 Second bypass pipe (bypass pipe) 71 First valve 72 Second valve 73 Third valve 74 Fourth valve 75 Fifth valve L Liquid W Workpiece

Claims

1. A supply tank for storing a liquid, a head having a discharge portion for discharging the liquid onto a workpiece, a flow path portion having a pipe for supplying the liquid from the supply tank to the head, and the head has a first port through which the liquid can pass, and a second port through which the liquid can pass, and for a coating operation of discharging the liquid from the discharge portion and applying the liquid to the workpiece, a first supply state in which the supply tank and the head are connected through the first port to supply the liquid to the head, a second supply state in which the supply tank and the head are connected through the second port to supply the liquid to the head, and can be alternatively switched, a coating device.

2. The coating device according to claim 1, further comprising a waste liquid portion for receiving the liquid discharged from the head through the first port or the second port.

3. The flow path portion has a first pipe connecting the first port and the supply tank, a second pipe connected to the second port, a bypass pipe connecting the first pipe and the second pipe, and a valve whose opening / closing state is switched to flow the liquid in the supply tank to the head through either one of the first port and the second port, and is the coating device according to claim 1 or claim 2.

4. For a discharging operation of flowing the liquid from the head to the waste liquid portion to discharge gas contained in the liquid in the head, a first discharge state in which the first port and the waste liquid portion are connected through the pipe in the flow path portion to discharge the liquid in the head to the waste liquid portion, a second discharge state in which the second port and the waste liquid portion are connected through the pipe in the flow path portion to discharge the liquid in the head to the waste liquid portion, and can be alternatively switched, is the coating device according to claim 2.

5. The flow path portion has a first pipe connecting the first port and the supply tank, a second pipe connecting the second port and the waste liquid portion, a bypass pipe connecting the first pipe and the second pipe, and a valve whose opening / closing state is switched to flow the liquid in the head to the waste liquid portion through either one of the first port and the second port, and is the coating device according to claim 4.

6. During the discharging operation, switch from one of the first discharge state and the second discharge state to the other, is the coating device according to claim 4 or claim 5.

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