TW201622831A - Coating device and accumulated gas removing method - Google Patents

Abstract

The invention provides a coating device and accumulated gas removing method capable of easily removing the accumulated gas in the pipe. The composition of the coating device according to the invention is that: a coating liquid tank storing coating liquid and a coating unit spraying the coating liquid are connected through a plurality of pipes, and the coating liquid of the coating liquid tank is sprayed through the coating unit. The aforesaid pipes are connected through the pipe connection part making the pipes to connect with each other, and is characterized by having a counter-flow liquid-sending device, which delivers the liquid toward the aforesaid coating liquid tank side through the aforesaid pipes, between the pipe connection part and the coating unit that are arranged in the position nearest the aforesaid coating unit.

Description

Coating device and method for removing accumulated gas

The present invention relates to a coating apparatus and an accumulated gas removing method for applying a coating liquid onto a substrate, and more particularly to a coating apparatus capable of easily removing a gas existing in a pipe connecting the coating nozzles from a coating liquid tank in the coating apparatus and Accumulated gas removal method.

In a flat panel display such as a liquid crystal display or a plasma display, a resist liquid (referred to as a coated substrate) is applied to a substrate made of glass or the like. This coated substrate is formed by a coating apparatus that uniformly applies a resist liquid (hereinafter referred to as a coating liquid). In other words, the coating apparatus includes a stage on which the substrate is placed, and a coating unit having a head portion that ejects the coating liquid, and the coating operation of moving the substrate and the coating unit while ejecting the coating liquid from the slit nozzle of the head portion is performed. A coating film of a specific thickness is formed on the substrate.

Here, FIG. 6 is a view showing a path of the pipe 102 of the coating device. The coating liquid supplied to the coating unit 100 is stored in the coating liquid tank 101, and is supplied by connecting the coating liquid tank 101 and the tubular pipe 102 of the coating unit 100. The pipe 102 is formed by connecting the pipe connecting portions 103 of the connecting pipes 102 such as the pipe 102 joint or the valve. Then, the coating liquid tank 101 is pressurized by a liquid feeding pressurizing device (not shown), and the coating liquid of the coating liquid tank 101 is transported to the pump 104 provided on the path of the piping 102. Then, by operating the pump 104, the coating liquid is ejected from the head portion of the coating unit 100 to form a coating film on the substrate.

In general, in such a coating apparatus, a liquid passing step is performed as a preparation step for performing a coating operation. This liquid passing step is to flow the coating liquid in the pipe 102 in a dry state. The step of filling the coating liquid in the piping 102 is performed when the coating apparatus is operated for the first time or when the coating liquid is changed. Specifically, the inside of the coating liquid tank 101 in which the coating liquid is placed is a low pressure, and the coating liquid is sufficiently degassed (see, for example, Patent Document 1 below). Thereby, it is possible to suppress the occurrence of uneven coating due to fluctuations in the discharge pressure when the coating liquid is ejected when a gas is present in the coating liquid. Then, the coating liquid is sent from the coating liquid tank 101 to the coating unit 100 side through the pipe 102 (passing liquid step). As a result, the accumulated gas existing in the pipe 102 is sent to the coating unit 100 (head unit) together with the coating liquid, and the slit nozzle from the head portion is discarded together with the coating liquid. Then, the gas discharge processing for removing the air bubbles remaining in the head portion is finally performed (for example, refer to Patent Document 2 below). Thereby, a coating film is formed by removing the gas in the coating liquid, and a stable coating film is formed on the substrate.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2011-139972

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2005-144376

However, it is difficult to remove the gas in the coating liquid by the above-described degassing treatment and gas discharge treatment. In other words, the pipe connecting portion 103 such as the pipe 102 joint or the valve is provided at a plurality of positions of the pipe 102, and the accumulated gas is formed in the pipe connecting portion 103. Specifically, as shown in FIG. 7 , the pipe connecting portion 103 has an ineffective space 105 such as a concavo-convex portion or a curved portion. Therefore, the accumulating gas 106 is easily formed in the ineffective space 105 ( FIG. 7( a )). Therefore, in the liquid passing step, there is a problem that even if the coating liquid 107 subjected to the deaeration treatment is conveyed, the gas in the pipe 102 escapes to the ineffective space 105 to form the accumulated gas 106. When the accumulated gas 106 is formed in the dead space 105, even if the accumulated gas 106 continues to remain in the dead space 105 (Fig. B(b)) during the liquid feeding, even if the liquid feeding operation is completed After the gas discharge treatment, the accumulated gas 106 in the pipe 102 cannot be removed, and as a result, the coating accuracy is affected.

The present invention has been made in view of the above problems, and it is an object of the invention to provide a coating apparatus and an accumulating gas removing method which can easily remove an accumulated gas in a pipe.

In order to solve the problem, the coating apparatus of the present invention connects a coating liquid tank for storing a coating liquid to a coating unit for discharging a coating liquid by connecting a plurality of pipes, and the coating liquid of the coating liquid tank is ejected by the coating unit. In the above-mentioned piping, the piping is connected to each other by a pipe connecting portion between the connecting pipes, and the pipe connecting portion and the coating unit disposed at a position closest to the coating unit are provided to the pipe through the pipe. A countercurrent liquid feeding device for feeding liquid on the coating liquid tank side.

Since the coating device is provided with a reverse flow liquid supply device, the accumulated gas remaining in the pipe in the liquid passing step can be removed. In other words, in the liquid-passing step, the coating liquid is supplied from the coating liquid tank to the coating liquid unit side (positive flow direction), and the coating liquid is filled in the piping, and then the coating liquid in the piping is transferred to the coating liquid by the reverse flow liquid feeding device. Slot side (countercurrent direction). Then, as the coating liquid is conveyed in the forward flow direction, the liquid supply of the coating liquid is alternately repeated in the forward flow direction and the reverse flow direction, and finally the coating liquid is discarded from the coating liquid unit, whereby the storage portion can be retained in the piping connection portion. The accumulation of gas in the dead space is removed. In other words, the accumulated gas which is blocked in the ineffective space (concave portion or curved portion) of the pipe connection portion due to the liquid supply in the forward flow direction is released from the fixed direction (positive flow direction) by the liquid supply in the reverse flow direction. Therefore, the blockage is released and moved in the countercurrent direction. Then, by supplying the liquid in the forward flow direction again, the accumulated gas is accelerated at a speed corresponding to the movement in the countercurrent direction, passes through the uneven portion or the bent portion, and is conveyed in the forward flow direction together with the coating liquid. Further, since all the pipe connecting portions are located closer to the coating liquid tank than the countercurrent liquid feeding device, the effect of the movement of the accumulated gas due to the backflow can be obtained in all the pipe connecting portions. That is, when it is convenient to pass through the concave or convex portion or the curved portion in the liquid feeding in the countercurrent direction, it is also possible to alternately The liquid supply in the forward flow direction and the reverse flow direction is repeated, and the accumulated gas is passed through the uneven portion or the bent portion, so that the accumulated gas can be easily removed from the dead space.

Further, the backflow liquid supply device may be configured to include a counterflow pipe connecting portion that is disposed at the pipe connecting portion that is disposed closest to the coating unit, and the above-described Between the coating units, a counterflow tank connected to the counterflow piping connecting portion via a pipe and storing the coating liquid, and a liquid feeding pressurizing device that applies a pressing force to the counterflow tank to supply the liquid.

For example, by using the three-way valve as the counterflow pipe connecting portion, the communication between the countercurrent liquid feeding device and the coating tank can be easily switched, and the countercurrent liquid feeding device and the coating unit can communicate with each other. Therefore, the coating liquid can be formed by a simple configuration. The flow direction is switched to the positive flow direction and the reverse flow direction.

In order to solve the problem, the method of removing an accumulated gas according to the present invention is a method for removing an accumulated gas in a coating apparatus that connects a plurality of pipes by a pipe connecting portion that connects pipes to each other to store a coating liquid. The coating liquid tank is connected to the coating unit that ejects the coating liquid, and a counterflow that feeds the liquid to the coating liquid tank through the pipe is connected between the pipe connecting portion disposed at a position closest to the coating unit and the coating unit. a liquid supply device; the method for removing accumulated gas in the coating device, comprising: a positive flow liquid supply step of conveying a coating liquid having a maximum capacity of at least more than a capacity of each of the pipe connection portions from the coating tank to the coating unit a countercurrent liquid feeding step for conveying a coating liquid having a maximum capacity of at least more than the capacity of each of the pipe connecting portions from the above-mentioned skip flow liquid feeding device to the coating tank; and a gas discharging step which is present in the coating unit The gas is discharged; and the above-mentioned positive-flow liquid feeding step and the above-mentioned counter-current liquid feeding are alternately repeated at least one time or more After the step, the above gas discharge step is performed.

According to the above-described accumulated gas removal method, the accumulated gas remaining in the pipe in the liquid passing step can be removed by alternately repeating at least one of the positive flow liquid supply step and the reverse flow liquid supply step. That is, due to the ineffective space of the coating liquid in the pipe connection portion due to the positive flow liquid feeding step The accumulated gas formed by the obstruction or the curved portion is transported in the countercurrent direction by the countercurrent liquid supply step, and the pressing force is released from the fixed direction (positive flow direction), so that the blocking is released and moved in the countercurrent direction. . At this time, in the positive flow liquid supply step and the reverse flow liquid supply step, the next liquid supply step (the positive flow liquid supply step or the counter current liquid supply step) is utilized by transporting at least the coating liquid having the largest capacity in the pipe joint portion. The accumulated gas can surely pass through the pipe joint. In other words, by supplying the liquid again in the forward flow direction, the accumulated gas is accelerated at a speed corresponding to the movement in the countercurrent direction, passes through the uneven portion or the bent portion, and is conveyed in the forward flow direction together with the coating liquid. That is, when it is difficult to pass through the uneven portion or the curved portion in the liquid feeding in the countercurrent direction, the liquid supply in the positive flow direction and the reverse flow direction may be alternately repeated, and the accumulated gas may be passed through the concave or convex portion or bent. And so that the accumulated gas can be easily removed from the ineffective space.

According to the coating apparatus and the accumulated gas removing method of the present invention, the accumulated gas in the piping can be easily removed.

1‧‧‧ Coating device

2‧‧‧ coating tank

3‧‧‧ Coating unit

4‧‧‧Pipe

5‧‧‧Pipe connection

6‧‧‧ Coating liquid pump

7‧‧‧Countercurrent liquid feeding device

8‧‧‧Reflow piping connection

9‧‧‧Invalid space

10‧‧‧ Coating device body

11‧‧‧ platform

21‧‧‧ Liquid feeding device

22‧‧‧Overflow valve

31‧‧‧ feet

34‧‧‧Spray Department

34a‧‧‧Slit nozzle

51‧‧‧T-shaped pipe joint

52‧‧‧L type pipe joint

53‧‧‧ suction valve

54‧‧‧Spray valve

71‧‧‧Reverse flow slot

72‧‧‧ Liquid feeding device

73‧‧‧Relief valve

81‧‧‧Three-way valve

91‧‧‧ accumulating gas

100‧‧‧ Coating unit

101‧‧‧ coating tank

102‧‧‧Pipe

103‧‧‧Pipe connection

104‧‧‧ pump

105‧‧‧Invalid space

106‧‧‧ accumulating gas

107‧‧‧ Coating solution

S1~S5‧‧‧Steps

W‧‧‧Substrate

Fig. 1 is a view schematically showing a piping system of a coating apparatus of the present invention.

Fig. 2 is a schematic perspective view of the main body of the coating apparatus.

Fig. 3 is a view showing the vicinity of the leg portion of the coating unit of the coating device.

Fig. 4 is a view showing the ineffective space and the accumulated gas in the pipe connecting portion, wherein (a) shows a state in which the coating liquid is filled in the pipe immediately after the coating liquid is filled, and (b) shows that the liquid is supplied in the countercurrent direction. (c) is a diagram showing a state in which liquid is supplied to the positive flow direction.

Fig. 5 is a flow chart showing the method of removing accumulated gas of the present invention.

Figure 6 is a piping system diagram of a prior coating apparatus.

Fig. 7 is a view showing the dead space and the accumulated gas in the previous pipe connecting portion, wherein (a) shows a pattern immediately after filling the coating liquid in the pipe by the liquid passing step, and (b) shows the case from (a). A state in which the state of the liquid is further supplied.

Embodiments of the present invention will be described using the drawings.

Fig. 1 is a schematic view showing a piping system of a coating apparatus according to the present invention, Fig. 2 is a schematic perspective view of the main body of the coating apparatus, and Fig. 3 is a view showing a vicinity of a leg portion of a coating unit of the coating apparatus.

As shown in FIGS. 1 to 3, the coating device 1 includes a coating liquid tank 2 for storing a coating liquid, and a coating device main body 10 including a coating unit 3 for discharging a coating liquid supplied from the coating liquid tank 2. The coating liquid tank 2 and the coating apparatus main body 10 are connected to each other by a plurality of pipes 4, and the connecting portions of the pipes 4 are connected by a valve or a pipe joint. In the present invention, a valve or a pipe joint or the like for connecting the pipes 4 to each other is collectively referred to as a pipe connecting portion 5. Further, a coating liquid pump 6 is provided between the coating liquid tank 2 and the coating unit 3, and the coating liquid pump 6 is actuated by filling the coating liquid pump 6 with a coating liquid of a desired amount from the coating liquid tank 2. On the other hand, the coating unit 3 of the coating apparatus main body 10 ejects the coating liquid, and forms a coating film on the substrate fixed to the coating apparatus main body 10.

The coating liquid tank 2 is a liquid material (hereinafter referred to as a coating liquid) such as a chemical liquid or a resist liquid which is a material of a coating film formed on the substrate W. The coating liquid tank 2 is provided with a bubble removing mechanism to prevent air bubbles or the like from being mixed into the coating liquid to be stored. In the coating liquid tank 2, a liquid feeding pressurizing device 21 is provided, and by applying the liquid feeding pressurizing device 21, the coating liquid in the coating liquid tank 2 can be transported to the downstream side. In other words, the pipe 4 is connected to the bottom surface of the coating liquid tank 2, and the inside of the coating liquid tank 2 is pressurized by the liquid feeding and pressurizing device 21, thereby passing the pipe 4 to the coating liquid pump 6, the coating unit 3, and the like located on the downstream side. The coating liquid is delivered. In the present embodiment, the liquid-feeding pressurizing device 21 supplies a clean dry gas (CDA) to the coating liquid tank 2, and by supplying CDA into the coating liquid tank 2, the coating liquid tank 2 is pressurized. The coating liquid is delivered. Further, the coating liquid tank 2 is provided with a relief valve 22, and after the pressure in the coating liquid tank 2 is opened, the overflow valve 22 is opened to return the inside of the coating liquid tank 2 to atmospheric pressure, thereby applying the inside of the coating liquid tank 2. open put.

The coating apparatus main body 10 is formed by forming a coating film of a liquid material (hereinafter referred to as a coating liquid) such as a chemical liquid or a resist liquid on the substrate W, and includes a stage 11 on which the substrate W is placed, and The platform 11 can be configured to move the coating unit 3 in a specific direction.

Moreover, the coating unit 3 is a method in which a coating liquid is discharged onto the substrate W to form a coating film. As shown in FIGS. 2 and 3, the coating unit 3 has a leg portion 31 movable in the X-axis direction and a head portion 34 extending in the Y-axis direction. The head portion 34 is connectable to the substrate W held by the stage 11. / Supported separately. The head portion 34 is a person who ejects a coating liquid to form a coating film on the substrate W. The head portion 34 of the present embodiment has a columnar member having a shape extending in one direction, and is provided to be substantially orthogonal to the traveling direction of the leg portion 31 of the coating unit 3. Further, the head portion 34 is formed with a slit nozzle 34a extending in the longitudinal direction, and the coating liquid supplied to the head portion 34 is uniformly discharged from the slit nozzle 34a in the longitudinal direction.

Specifically, a manifold for storing the coating liquid is formed in the head portion 34, and the coating liquid supplied from the coating liquid supply port is temporarily stored. In other words, the coating liquid supply port is connected to the pipe 4, and the coating liquid conveyed from the coating liquid pump 6 described below is supplied into the manifold through the coating liquid supply port, and the coating liquid pump 6 is actuated to coat the inside of the manifold. The liquid is ejected through the slit nozzle 34a. Therefore, the coating unit 3 is moved in the X-axis direction while the coating liquid is ejected from the slit nozzle 34a, and a coating film having a constant thickness is formed on the substrate W in the longitudinal direction of the slit nozzle 34a.

Further, a gas discharge hole is formed in the shower head portion 34, and a gas such as a bubble or an accumulated gas contained in the coating liquid stored in the manifold is discharged through the gas discharge hole by performing a gas discharge process.

Moreover, the coating liquid pump 6 conveys the coating liquid supplied from the coating liquid tank 2 to the coating apparatus main body 10. The coating liquid pump 6 is connected to the pipe 4, and is connected to and connected to the coating liquid tank 2 and the coating unit 3 via the pipe coupling portion 5 which is the T-shaped pipe joint 51. In the present embodiment, a syringe pump is provided, and the amount of coating required for one substrate is accommodated by a suction operation. The liquid can be transported to the coating device body 10 by a discharge operation.

Further, the coating liquid tank 2, the coating liquid pump 6, and the coating apparatus main body 10 (coating unit 3) connect and connect a plurality of pipes 4 to each other. Specifically, the plurality of pipes 4 are connected by a pipe connecting portion 5 such as a valve or a pipe joint. In the example of Fig. 1, an L-shaped pipe joint 52 is provided at a portion where the path of the pipe 4 is bent at a right angle, and a T-shaped pipe joint 51 is provided at a portion to be connected to the coating liquid pump 6. In other words, a flow path for connecting the coating liquid tank 2, the coating liquid pump 6, and the coating apparatus main body 10 is formed by providing an appropriate piping joint as needed.

Further, a valve is provided in the path of the pipe 4, and in the example of Fig. 1, a suction valve 53 is provided between the coating liquid tank 2 and the coating liquid pump 6, and is disposed between the coating liquid pump 6 and the coating device body 10. There is a discharge valve 54. For the suction valve 53 and the discharge valve 54, for example, a diaphragm valve is used. By opening or closing the suction valve 53 and the discharge valve 54, the flow path formed by the pipe 4 can be switched. For example, by opening the suction valve 53, the discharge valve 54 is closed, and the coating liquid tank 2 is connected to and connected to the coating liquid pump 6, so that the coating liquid can be supplied from the coating liquid tank 2 to the coating liquid pump 6. Further, by closing the suction valve 53, the discharge valve 54 is opened, and the coating liquid pump 6 is connected to and connected to the coating unit 3, so that the coating liquid can be supplied from the coating liquid pump 6 to the coating unit 3.

Moreover, the coating apparatus 1 of the present invention is provided with a countercurrent liquid feeding device 7 that transports the coating liquid in the countercurrent direction. The counter-current liquid supply device 7 transports the coating liquid to the counterflow direction from the coating unit 3 side to the coating liquid tank 2 side with respect to the positive flow direction in which the coating liquid flows from the coating liquid tank 2 side toward the coating unit 3 side. The reverse flow liquid supply device 7 includes a reverse flow tank 71, a liquid supply pressurizing device 72 for pressurizing the reverse flow tank 71, and a counterflow pipe connecting portion 8. Specifically, the counterflow pipe connecting portion 8 is provided between the discharge valve 54 and the coating unit 3, and the counterflow pipe connecting portion 8 communicates with the counterflow pipe connecting portion 8 via the pipe 4 to connect the counterflow groove 71. Thereby, the coating liquid of the counterflow tank 71 is conveyed to the coating liquid tank 2 side through the piping 4.

The counterflow tank 71 is the same as the above-described coating liquid tank 2, and is a storage liquid. Similarly to the coating liquid tank 2, a bubble removing mechanism is provided to prevent air bubbles or the like from being mixed into the coating liquid to be stored. Further, in the counterflow tank 71, a liquid supply pressurizing device 72 is also provided, When the liquid feeding and pressurizing device 72 is actuated, the coating liquid in the counterflow tank 71 can be transported to the upstream side. In other words, the pipe 4 is connected to the bottom surface of the coating liquid tank 2, and the inside of the coating liquid tank 2 is pressurized by the liquid feeding and pressurizing device 72, and can be conveyed and coated to the coating liquid tank 2 on the upstream side by the pipe 4. Liquid (to make it countercurrent). In the counterflow tank 71, the overflow valve 73 is provided, and after the counterflow tank 71 is pressurized, the relief valve 73 is opened to return the inside of the counterflow tank 71 to the atmospheric pressure, whereby the counterflow tank 71 is opened. .

Further, the pipe connecting portion 8 for the counterflow is connected and connected to the pipe 4 connected to the counterflow groove 71 and the pipe 4 connecting the coating liquid tank 2 and the coating unit 3, and is connected to the counter flow tank 71 and the coating liquid tank 2. The flow path and the flow path connecting the counterflow tank 71 and the coating unit 3 are switched. The counterflow pipe connecting portion 8 and the pipe connecting portion 5 are common to the connecting pipe. However, in the present invention, the concept is different, and only the counterflow groove 71 is connected.

The counterflow pipe connecting portion 8 is disposed between the discharge valve 54 (pipe connecting portion 5) provided at a position closest to the coating unit 3 and the coating unit 3. In other words, when the counter-flowing tank 71 flows back to the coating liquid tank 2, the coating liquid conveyed from the counterflow tank 71 passes through the counterflow piping connecting portion 8 and is located above the counterflow piping connecting portion 8 All the pipe connecting portions 5 on the side (the side of the coating liquid tank 2) are conveyed to the coating liquid tank 2.

In the counterflow pipe connecting portion 8, the three-way valve 81 is used in the present embodiment, and the counterflow groove 71, the coating unit 3, and the coating liquid tank 2 are connected and connected by the three-way valve 81. In other words, by operating the three-way valve 81, the connection between the counterflow groove 71 and the coating unit 3, and the connection between the counterflow groove 71 and the coating liquid tank 2 can be switched. Further, the counterflow pipe connecting portion 8 can also combine the T-shaped pipe joint 51 and the diaphragm valve. In other words, the pipe 4 from the coating liquid tank 2, the coating unit 3, and the counterflow groove 71 is connected to the T-shaped pipe joint 51, and a diamondphragm valve is provided between the reverse flow groove 71 and the T-shaped pipe joint 51. The connection between the counterflow groove 71 and the coating unit 3, and the connection between the counterflow groove 71 and the coating liquid tank 2 are switched.

Next, the method of removing the accumulated gas of the coating device 1 will be described based on the flowchart shown in FIG. 5. The accumulated gas removal can be removed from the state in which all the pipes 4 are dried. When the coating liquid is supplied to the coating device 1 once, or when the coating liquid is exchanged, the accumulated gas remaining in the pipe 4 is accumulated.

First, the coating liquid filling step (liquid passing step) is performed by step S1. This coating liquid filling step is a processing step for filling the inside of the air-filled pipe 4 with the coating liquid. In the present embodiment, the air from the flow-reverse groove 71 to the flow path of the discharge valve 54 is discharged, and then the air from the coating liquid tank 2 to the flow path of the three-way valve 81 is intermittently discharged. Specifically, after the degassing treatment is performed on the coating liquid stored in the counterflow tank 71, the three-way valve 81 is opened in the counterflow direction (closed from the counterflow tank 71 in the direction of the coating unit 3, and opened in the direction of the coating liquid tank 2). The discharge valve 54 and the suction valve 53 are opened, and the pressurized liquid supply device of the reverse flow tank 71 is actuated to transport the coating liquid from the counterflow tank 71 to the coating liquid tank 2 side (countercurrent direction). Thereby, the coating liquid is conveyed from the counterflow tank 71 to the coating liquid tank 2 side via the three-way valve 81. At this time, the air in the pipe 4 is pressed by the coating liquid in the countercurrent direction and discharged to the coating liquid tank 2. Then, the liquid supply state in the piping 4 is confirmed, and the pressurized liquid supply device of the reverse flow tank 71 is stopped in a state where the coating liquid is filled in the piping 4 from the reverse flow tank 71 to the discharge valve 54. The flow valve 73 is opened to open the counterflow groove 71 to the atmosphere.

Then, the coating liquid is supplied to the coating liquid tank 2, and the coating liquid stored in the coating liquid tank 2 is subjected to a degassing treatment, and then the three-way valve 81 is switched so that the coating liquid flows from the coating liquid tank 2 to the coating unit 3 side. . Then, the pressurized liquid supply device of the coating liquid tank 2 is operated to transport the coating liquid in the forward flow direction. In other words, a large amount of air is present on the side of the coating liquid tank 2 from the portion where the coating liquid is not transported by the coating liquid in the reverse flow direction in the previous direction, but the coating liquid is applied from the coating liquid tank 2 In the forward flow direction, the coating liquid is discharged from the slit nozzle through the manifold of the coating unit 3 together with the air. Thereby, the coating liquid 4 from the coating liquid tank 2 to the counterflow tank 71 is filled with the coating liquid. Then, after the pressurized liquid feeding device that turns the coating liquid is stopped, the overflow valve 22 is opened to open the coating liquid tank 2 to the atmosphere.

Next, a countercurrent liquid feeding step is performed by step S2. The accumulation gas in the pipe 4 is removed by the reverse flow liquid supply step and the subsequent positive flow liquid supply step. That is, by In the coating liquid filling step, the air existing in the pipe 4 is removed, and the inside of the pipe 4 from the coating liquid tank 2 to the counterflow tank 71 is substantially filled with the coating liquid. However, since the air is easily trapped in the dead space of the pipe connecting portion 5 and the accumulated gas is slightly formed, it is necessary to exclude the accumulated gas.

Specifically, the three-way valve 81 is set so as to flow the coating liquid from the counterflow groove 71 to the coating liquid tank 2 in the countercurrent direction. Then, the liquid feeding and pressurizing device 72 of the counterflow tank 71 is operated to transport the coating liquid in the countercurrent direction. At this time, the amount of liquid to be supplied is a coating liquid that is transported more than the maximum capacity of the pipe connecting portion 5. Here, the capacity of the pipe connecting portion 5 is the capacity from the connection portion of the pipe joint or the valve of the pipe connecting portion 5 to the connection portion with the pipe 4 of the other side. Further, the coating liquid having the largest capacity among all the pipe connecting portions 5 used in the path of the pipe 4 is transported. In the example of Fig. 1, the discharge valve 54, the suction valve 53, and the maximum volume of the coating liquid in each of the pipe joints are conveyed. Thereby, the gas of the accumulated gas remaining in the ineffective space moves in the countercurrent direction.

Next, a positive flow liquid feeding step is performed by step S3. Specifically, the liquid feeding and pressurizing device 72 of the counterflow tank 71 is stopped, and after the relief valve 73 is opened, the three-way valve 81 is flown in the positive flow direction, that is, from the coating liquid tank 2 to the coating unit 3 side. Switch. Then, the liquid supply pressurizing device 21 of the coating liquid tank 2 is operated to transport the coating liquid in the forward flow direction. Regarding the liquid supply amount, the coating liquid having a larger capacity than the maximum capacity of the pipe connecting portion 5 is transported. Thereby, the accumulated gas 91 can be removed from the dead space of the pipe connecting portion 5. In other words, as shown in FIG. 4, the coating liquid is transported by the coating liquid filling step, and when the accumulated gas 91 is formed in the dead space 9 of the pipe connecting portion 5, the accumulated gas 91 is blocked in the dead space 9, even if the coating liquid is filled. In the direction in which the medium is conveyed, the liquid supply is performed, and since the pressing direction added to the accumulated gas 91 is the same, the ineffective space 9 cannot be passed, and the accumulated gas 91 is retained at the position (Fig. 4(a)). Therefore, by applying the countercurrent liquid supply step to the counterflow direction in the pipe 4, the pressing force in the positive flow direction of the accumulating gas 91 formed in the ineffective space 9 is released, and the transport is more than the most in the pipe connecting portion 5. a coating liquid of a capacity, whereby the position in the countercurrent direction away from the ineffective space 9 Moving, the block in the invalid space 9 is released (Fig. 4(b)). Then, the coating liquid is conveyed in the forward flow direction in the pipe 4 by the positive flow liquid supply step, and the accumulated gas 91 moved from the ineffective space 9 is moved in the forward flow direction. At this time, by transporting the coating liquid having the largest capacity among the pipe connecting portions 5, the accumulated gas 91 moved in the counter-current liquid feeding step is brought closer to the positive flow direction toward the position of the previously blocked empty space 9 together with the coating liquid. The side is conveyed, whereby the previously ineffective void space 9 can be passed (Fig. 4(c)). Further, the three-way valve 81 of the counter-current liquid supply device 7 is disposed between the pipe connecting portion 5 provided at the position closest to the coating unit 3 and the coating unit 3, and all the pipe connecting portions 5 are located closer to the three-way valve 81. The gas 91 is accumulated in the entire pipe joint portion 5 so as to pass through the previously ineffective space 9 blocked. In addition, even when the accumulated gas 91 is formed in the dead space 9 of the three-way valve 81 (reverse flow pipe connecting portion 8), the above-described effects can be obtained in the same manner as the pipe connecting portion 5.

Next, it is confirmed whether or not there is a bubble in the invalid space 9 (step S4). When the air bubbles are present in the dead space 9 by the countercurrent liquid feeding step and the normal liquid feeding step, the step S4 proceeds to the No direction, and the reverse flow feeding step of the step S2 and the step S3 are performed again. The liquid feeding step is repeated until the bubbles of the dead space 9 disappear. Then, if the bubble disappears in the dead space 9, the process proceeds in the Yes direction in step S4, and the gas discharge step in the next step is performed. Further, the confirmation step may be performed visually, or may be performed by providing a sensor or the like to detect the presence or absence of a bubble in the dead space 9. Further, according to the adjustment test of the coating apparatus 1 in advance, it is understood that the bubble can be removed from the dead space 9 by performing the reverse flow liquid supply step and the normal flow liquid supply step a predetermined number of times, and the reverse flow liquid supply step of repeating the number of times can be repeated. And after the positive flow step, the next step is entered. By repeating the plurality of times as described above, even in the case of the reverse flow liquid supply step and the positive flow liquid supply step, the accumulation gas 91 can be prevented from passing through the dead space 9 when the dead space 9 is blocked. The accumulated gas 91 retained in the dead space 9 can be removed.

Next, the gas discharge step is performed by step S5. After the three-way valve 81 is switched in the forward flow direction, the coating liquid is transferred from the coating liquid tank 2 from the coating unit 3 The slit nozzle discharges the coating liquid. At this time, the accumulating gas 91 having passed through the dead space 9 in the countercurrent liquid feeding step and the normal flow liquid feeding step is sent to the manifold of the coating unit 3 together with the coating liquid, and is discharged from the slit nozzle or the gas discharge hole. Thereby, the state in which the accumulated gas 91 is not formed can be formed in the piping 4 from the coating liquid tank 2 to the coating unit 3.

As described above, the accumulating gas 91 remaining in the pipe 4 in the liquid passing step can be removed by repeating the positive flow liquid supply step and the reverse flow liquid supply step at least once alternately. In other words, the accumulating gas 91 formed by the coating liquid in the dead space 9 (concavo-convex portion or curved portion) of the pipe connecting portion 5 is prevented from being transported in the countercurrent direction by the countercurrent liquid feeding step. Since the pressing in the fixed direction (positive flow direction) is released, the blocking is released and moved in the reverse flow direction. At this time, by supplying the coating liquid having at least more than the maximum capacity in the pipe connecting portion 5 in the normal flow liquid feeding step and the reverse flow liquid feeding step, the next liquid feeding step (positive flow liquid feeding step or reverse flow feeding) can be utilized. In the liquid step), the accumulated gas 91 is surely passed through the pipe joint portion 5. In other words, by accumulating the liquid in the forward flow direction again, the accumulated gas 91 is accelerated at a speed corresponding to the movement in the countercurrent direction, passes through the uneven portion or the curved portion, and is conveyed in the forward flow direction together with the coating liquid. That is, in the case where it is not possible to pass through the uneven portion or the curved portion in the liquid feeding in the countercurrent direction, the accumulating gas 91 can be passed through the uneven portion or by alternately repeating the liquid feeding in the positive flow direction and the reverse flow direction. The bent portion is such that the accumulated gas 91 can be easily removed from the dead space 9.

Further, in the above embodiment, after the coating liquid filling step, the reverse flow liquid feeding step and the normal flow liquid feeding step are sequentially described. However, after the coating liquid filling step, the positive liquid feeding step may be followed. The sequence of the countercurrent liquid feeding step is performed.

Further, in the above embodiment, an example in which a plurality of countercurrent liquid supply steps and a positive flow liquid supply step are performed by repeating the steps will be described, but by performing only one countercurrent liquid supply step and a positive current liquid supply step. When the accumulated gas 91 can be removed, only the reverse flow liquid supply step and the normal flow liquid supply step may be performed once, and the confirmation step of the above step S4 may be omitted.

1‧‧‧ Coating device

2‧‧‧ coating tank

3‧‧‧ Coating unit

4‧‧‧Pipe

5‧‧‧Pipe connection

6‧‧‧ Coating liquid pump

7‧‧‧Countercurrent liquid feeding device

8‧‧‧Reflow piping connection

10‧‧‧ Coating device body

21‧‧‧ Liquid feeding device

22‧‧‧Overflow valve

51‧‧‧T-shaped pipe joint

52‧‧‧L type pipe joint

53‧‧‧ suction valve

54‧‧‧Spray valve

71‧‧‧Reverse flow slot

72‧‧‧ Liquid feeding device

73‧‧‧Relief valve

81‧‧‧Three-way valve

W‧‧‧Substrate

Claims (3)

A coating apparatus that connects a coating liquid tank for storing a coating liquid to a coating unit that discharges a coating liquid by connecting a plurality of pipes, and the coating liquid of the coating liquid tank is discharged by the coating unit; The piping is connected by a pipe connecting portion between the connecting pipes, and the pipe connecting portion and the coating unit disposed at a position closest to the coating unit are provided with liquid to the coating liquid tank side through the pipe. Countercurrent liquid delivery device. In a coating device, the countercurrent liquid supply device includes a counterflow pipe connecting portion disposed between the pipe connecting portion provided at a position closest to the coating unit and the coating unit, and a counterflow groove. The pipe for the counterflow pipe is connected to the counterflow pipe connecting portion via a pipe, and the liquid feeding pressurizing device applies a pressing force to the counterflow groove to supply the liquid. A method for removing an accumulated gas in a coating device, wherein the coating device is connected to a coating unit for discharging a coating liquid by connecting a plurality of pipes by a pipe connecting portion that connects the pipes to each other, and A countercurrent liquid feeding device that supplies liquid to the coating liquid tank side through the pipe is connected between the pipe connecting portion disposed at a position closest to the coating unit and the coating unit, and is characterized in that: a positive flow feeding step is provided And conveying a coating liquid having a maximum capacity of at least more than the capacity of each of the pipe connecting portions from the coating tank to the coating unit; and a countercurrent liquid feeding step of conveying at least a plurality of the countercurrent liquid feeding device to the coating tank a coating liquid having a maximum capacity among the capacities of the respective pipe connecting portions; and a gas discharging step of discharging the gas existing in the coating unit; and repeating the positive current feeding step at least one time or more After the countercurrent liquid feeding step, the gas discharging step is performed.