Coating nozzle and coating apparatus

Abstract

To shorten the time of washing work and suppress a reduction in coating productivity.SOLUTION: A coating nozzle 10 comprises: a nozzle hole 1 which discharges a liquid coating material; a liquid chamber 2 which communicates with the nozzle hole 1; a coating material supply part 3 which supplies the liquid coating material to the liquid chamber 2; and a switching part 4 which switches whether the liquid coating material can be discharged from the nozzle hole 1. A washing liquid supply part 7 which supplies washing liquid is provided in the liquid chamber 2. With this, the time of washing work is shortened and a reduction in coating productivity is suppressed.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, there is known a coating nozzle having a nozzle hole from which a liquid paint is discharged, a liquid chamber communicating with the nozzle hole, a paint supply unit for supplying the liquid paint to the liquid chamber, and a switching unit for switching the discharge of the liquid paint from the nozzle hole.

[0003] For example, Patent Document 1 discloses an inkjet nozzle (coating nozzle) that switches the discharge of ink (liquid paint) from a nozzle hole by opening and closing the nozzle hole with a needle valve (switching unit) disposed in an ink chamber (liquid chamber) communicating with the nozzle hole.

Summary of the Invention

Problems to be Solved by the Invention

[0004] When cleaning the nozzle hole and the liquid chamber with a cleaning liquid to suppress paint clogging where the liquid paint clogs in the nozzle hole and the liquid chamber in the coating nozzle, there is a problem that the cleaning work takes time and the coating productivity decreases.

Means for Solving the Problems

[0005] In order to solve the above problems, The present invention a coating nozzle having a nozzle hole from which a liquid paint is discharged, a liquid chamber communicating with the nozzle hole, a paint supply unit for supplying the liquid paint to the liquid chamber, and a switching unit for switching the discharge of the liquid paint from the nozzle hole, Therefore, a needle valve opens and closes the paint inlet of the liquid chamber from which liquid paint is supplied from the paint supply unit. , A cleaning liquid supply unit that supplies cleaning liquid to the aforementioned liquid chamber, is characterized in that The needle valve is configured to close the paint inlet with its tip protruding from the paint inlet into the liquid chamber, and the cleaning liquid supply unit is configured such that the tip of the needle valve protruding from the paint inlet is cleaned. a cleaning liquid is supplied to the liquid chamber Ruko and the like.

Effects of the Invention

[0006] According to the present invention, since cleaning can be performed by introducing cleaning liquid into the liquid chamber and nozzle holes without using cleaning jigs, the time required for cleaning can be shortened and a decrease in coating productivity can be suppressed. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram illustrating the state in which the needle valve is in the closed position in a coating nozzle according to an embodiment. [Figure 2] This diagram schematically illustrates the state in which the needle valve is in the open position in the coating nozzle. [Figure 3] An explanatory diagram showing an example in which nozzle components are configured to be replaceable with respect to the coating nozzle body. [Figure 4] An explanatory diagram showing an example of a coating nozzle having a circulation path for circulating paint. [Figure 5] A schematic diagram showing an example of a coating apparatus using a coating nozzle in an embodiment. [Modes for carrying out the invention]

[0008] The following describes one embodiment in which the present invention is applied to a coating nozzle used in a coating apparatus. Figures 1 and 2 are schematic explanatory diagrams showing the coating nozzle 10 according to this embodiment. The coating nozzle 10 of this embodiment includes a nozzle hole 1 from which liquid paint (hereinafter simply referred to as "paint") is discharged, a liquid chamber 2 communicating with the nozzle hole 1, and a paint supply unit 3 that supplies paint to the liquid chamber 2. The coating nozzle 10 also includes a needle valve 4 as an opening / closing unit that opens and closes the paint inlet 2a of the liquid chamber 2, which serves as a switching unit to switch whether or not paint can be discharged from the nozzle hole 1. The coating nozzle 10 also includes a drive unit 5 that drives the needle valve, and an elastic diaphragm 6 as an intrusion prevention unit that prevents paint from the paint supply unit 3 from entering the housing space 11 that houses the drive unit 5. Furthermore, the coating nozzle 10 of this embodiment includes a cleaning liquid supply unit 7 that supplies cleaning liquid to the liquid chamber 2.

[0009] In the coating nozzle 10 of this embodiment, a paint supply unit 3 is connected to a paint supply mechanism 21, and a cleaning liquid supply unit 7 is connected to a cleaning liquid supply mechanism 22. The paint supply mechanism 21 and the cleaning liquid supply mechanism 22 can perform liquid supply operations independently of each other. Therefore, while the operation of supplying cleaning liquid from the cleaning liquid supply mechanism 22 to the cleaning liquid supply unit 7 is stopped, the operation of supplying paint from the paint supply mechanism 21 to the paint supply unit 3 can be performed. Conversely, while the operation of supplying paint from the paint supply mechanism 21 to the paint supply unit 3 is stopped, the operation of supplying cleaning liquid from the cleaning liquid supply mechanism 22 to the cleaning liquid supply unit 7 can be performed.

[0010] There are no particular restrictions on the paint supply mechanism 21 and the cleaning liquid supply mechanism 22, but syringe pumps, pressurized tanks, etc., can be suitably used. However, for the paint supply mechanism 21, if the paint impact efficiency of the paint discharged from the nozzle hole 1 is very high, it is preferable to have one that can control the supply even of minute amounts of paint.

[0011] Furthermore, in the coating nozzle 10 of this embodiment, when paint is not to be discharged from the nozzle hole 1, as shown in Figure 1, the needle valve 4 is moved to a closed position that closes the paint inlet 2a of the liquid chamber 2, thereby prohibiting the supply of paint from the paint supply unit 3 to the liquid chamber 2. On the other hand, when paint is to be discharged from the nozzle hole 1, as shown in Figure 2, the needle valve 4 is moved to an open position that opens the paint inlet 2a of the liquid chamber 2, thereby enabling the supply of paint from the paint supply unit 3 to the liquid chamber 2. In this way, by controlling the drive unit 5 to switch the needle valve 4 between the open position and the closed position, the paint sent from the paint liquid delivery mechanism 21 to the paint supply unit 3 can be discharged or not discharged from the nozzle hole 1 via the liquid chamber 2.

[0012] In this embodiment, the nozzle hole 1 discharges paint from the liquid chamber 2 during coating work and discharges paint and cleaning liquid from the liquid chamber 2 during cleaning work. The shape of the cross-section perpendicular to the discharge direction of the nozzle hole 1 is appropriately selected considering the characteristics of the object to be coated and the paint. Generally, a circular or square cross-section is preferred considering the ease of processing of the nozzle hole 1.

[0013] From the viewpoint of reducing uneven coating and reducing coating cycle time, the opening dimensions of the nozzle hole 1 are preferably such that the minimum dimension is 20 μm or more and the maximum dimension is 500 μm or less. For example, if the opening shape of the nozzle hole 1 is circular, it is preferable that its diameter is between 20 μm and 500 μm. Also, for example, if the opening shape of the nozzle hole 1 is square, it is preferable that the shorter side is 20 μm or more and the diagonal is 500 μm or less. If the minimum opening dimension of the nozzle hole 1 is less than 20 μm, the nozzle hole 1 is prone to clogging with foreign matter, and if the maximum opening dimension of the nozzle hole 1 exceeds 500 μm, uneven coating tends to worsen.

[0014] The nozzle hole 1 may be formed directly on the coating nozzle body, or a nozzle component including the discharge-side opening of the nozzle hole 1 may be integrally fixed to the coating nozzle body. However, from the viewpoint of maintainability, as shown in Figure 3, the nozzle component 12 including the opening (discharge-side opening) of the nozzle hole 1 may be configured to be replaceable with respect to the coating nozzle body. By making the nozzle component 12 replaceable in this way, it becomes easy to maintain (clean, etc.) the nozzle hole 1 or to change the shape and dimensions of the nozzle hole 1 according to the coating application.

[0015] There are no particular restrictions on the material of the component that forms the nozzle hole 1, but it is preferable that the material be corrosion-resistant to the paint and cleaning solution used.

[0016] There are no particular restrictions on the paint that can be used with the coating nozzle 10 of this embodiment, but it is preferable to appropriately select the viscosity and solid content concentration according to the opening size of the nozzle hole 1 and the amount of paint discharged during the coating operation. When the opening size of the nozzle hole 1 is small, if the viscosity of the paint is high, it may not be possible to discharge it or the discharge may be unstable. On the other hand, if the viscosity of the paint is lowered by lowering the solid content concentration of the paint, discharge becomes more stable, but problems may occur such as the amount of paint required to obtain the desired film thickness increasing, the wet film thickness on the object being coated becoming thicker, resulting in greater film thickness unevenness, and the touch-dry time becoming longer.

[0017] The paint may contain fine particles, but fine particles larger than the opening dimension of the nozzle holes 1 are likely to cause poor discharge, and poor discharge may not be restored even after cleaning. Therefore, sufficient consideration is required in selecting the particle size of the fine particles.

[0018] In order to suppress paint clogging where the liquid paint clogs in the nozzle holes and the liquid chamber in the coating nozzle 10, a method of cleaning the nozzle holes and the liquid chamber with a cleaning liquid is effective. However, the conventional method of cleaning with a cleaning liquid is a method of introducing the cleaning liquid from the outlet side of the nozzle holes using a cleaning jig for cleaning. Therefore, the cleaning operation is complicated and time-consuming, and the coating productivity is reduced. In this aspect, since a cleaning liquid supply unit for supplying a cleaning liquid to the liquid chamber is provided, the cleaning liquid can be introduced into the liquid chamber and the nozzle holes without using a cleaning jig, and the cleaning operation can be performed.

[0019] There are no particular restrictions on the cleaning liquid that can be used for the coating nozzle 10 of this embodiment. Generally, a cleaning liquid using the same solvent as that contained in the paint or a more soluble solvent is desirable. Specific examples include, for example, water, methanol, ethanol, toluene, tetrahydrofuran, methyl ethyl ketone, cyclohexanone, cyclopentanone, acetone, N-methyl-2-pyrrolidone, N,N-dimethylformamide, etc., but are not limited thereto.

[0020] The paint supply unit 3 includes a flow path for transporting the paint sent from the paint liquid feed mechanism 21 to the liquid chamber 2. The downstream end of the flow path of the paint supply unit 3 connected to the paint inlet 2a of the liquid chamber 2 has a tapered shape as shown in FIGS. 1 and 2. The tip side of the needle valve 4 is disposed in the paint supply unit 3. As shown in FIG. 1, when the tip of the needle valve 4 closes the downstream end of the flow path of the paint supply unit 3 (the paint inlet 2a of the liquid chamber 2) (closed position), the supply of paint from the paint supply unit 3 to the liquid chamber 2 is prohibited. On the other hand, as shown in FIG. 2, when the tip of the needle valve 4 retreats from the downstream end of the flow path of the paint supply unit 3 (the paint inlet 2a of the liquid chamber 2) (open position), the supply of paint from the paint supply unit 3 to the liquid chamber 2 becomes possible.

[0021] The drive unit 5 that drives the needle valve 4 biases the needle valve 4 toward the paint inlet 2a side of the liquid chamber 2 by the biasing force of a biasing member such as a spring, thereby positioning the needle valve 4 at the closed position. On the other hand, when positioning the needle valve 4 at the open position, the drive unit 5 includes a drive mechanism that moves the needle valve 4 backward with a force exceeding the biasing force of the biasing member to position it at the open position. There are no particular restrictions on this drive mechanism, but from the viewpoints of responsiveness, safety, and convenience, generally, an electromagnetic drive or an air drive is preferably used.

[0022] As the drive mechanism of the electromagnetic drive, for example, a solenoid can be used. The fixed core of the solenoid is arranged so as to face the magnetic body portion provided at the rear end portion of the needle valve, a current is passed through the solenoid to generate a magnetic field, and the rear end portion of the needle valve is adsorbed to the fixed core, thereby pulling down the needle valve 4 backward to position it at the open position. Such a drive mechanism can precisely control the opening and closing operation of the paint inlet 2a by the needle valve 4 by controlling the current supplied to the solenoid, so that it is possible to control the discharge pattern and discharge amount of the paint discharged from the nozzle hole 1 with high accuracy.

[0023] The drive mechanism of the air drive is suitable when safety and convenience are prioritized. In such a drive mechanism, the needle valve is driven to be lowered backward by utilizing the pressure of compressed air.

[0024] Also, as the drive mechanism of the drive unit 5, a piezoelectric element drive is also preferable. For example, the rear end portion of the needle valve 4 is fixed to the piezoelectric element, and the displacement of the piezoelectric element according to the applied voltage is utilized to move the needle valve 4 between the closed position and the open position. According to this, since the position of the needle valve 4 can be controlled at high speed, the opening and closing operation of the paint inlet 2a can be controlled with high responsiveness.

[0025] In this embodiment, an elastic diaphragm 6 is provided to separate the paint supply unit 3, where the tip of the needle valve 4 is positioned together with the paint, from the housing space 11, where the drive unit 5, positioned at the rear end of the needle valve 4, is housed. The elastic diaphragm 6 is provided to allow the needle valve 4 to move between a closed position and an open position while sealing the gap between the paint supply unit 3 and the housing space 11. Although the paint in the paint supply unit 3 is pressurized by the paint supply from the paint liquid delivery mechanism 21, the elastic diaphragm 6 prevents the paint in the paint supply unit 3 from entering the housing space 11.

[0026] The material of the elastic diaphragm 6 is preferably selected to match the solvent used in the paint. In particular, when using organic solvents, the material of the elastic diaphragm 6 being solvent-resistant extends the life of the elastic diaphragm 6 and enables stable operation over a long period of time. Furthermore, if there is a risk of cleaning liquid entering the paint supply unit 3, it is preferable that the material of the elastic diaphragm 6 be solvent-resistant to the solvent contained in the cleaning liquid.

[0027] When performing a coating operation using the coating nozzle 10, first, the supply of cleaning liquid from the cleaning liquid supply mechanism 22 to the cleaning liquid supply unit 7 is stopped, and then paint is supplied from the paint supply mechanism 21 to the paint supply unit 3. At this time, if the needle valve 4 is positioned in the closed position by the drive unit 5, and the paint inlet 2a of the liquid chamber 2 is closed by the needle valve 4, the paint supplied to the paint supply unit 3 will not be supplied to the liquid chamber 2, and no paint will be discharged from the nozzle hole 1.

[0028] When the paint supply unit 3 is filled with paint and the needle valve 4 is moved to the open position by the drive unit 5, a gap is created between the tip of the needle valve 4 and the downstream end of the flow path of the paint supply unit 3, and the paint inlet 2a of the liquid chamber 2, to which the downstream end of the flow path is connected, is opened. As a result, the paint in the paint supply unit 3 is supplied to the liquid chamber 2 from the paint inlet 2a, and the paint is discharged from the nozzle hole 1 which is in communication with the liquid chamber 2.

[0029] At this time, the operation of supplying cleaning liquid from the cleaning liquid supply mechanism 22 to the cleaning liquid supply unit 7 is stopped, so cleaning liquid is not supplied from the cleaning liquid supply unit 7 to the liquid chamber 2, and only paint is discharged from the nozzle hole 1. In this embodiment, the cleaning liquid inlet 2b of the liquid chamber 2 to which cleaning liquid is supplied from the cleaning liquid supply unit 7 is always open, but an opening / closing unit for opening and closing the cleaning liquid inlet 2b may be provided. In this case, by closing the cleaning liquid inlet 2b with the opening / closing unit when discharging paint, it is possible to stably suppress the mixing of cleaning liquid with the paint.

[0030] At the end of the coating process, the nozzle hole 1 and liquid chamber 2 are either coated with paint or filled with paint. If left in this state, the paint may harden or the paint components may settle, potentially causing clogging of the nozzle hole 1 and liquid chamber 2. An effective way to prevent this clogging is to clean the inside of the nozzle hole 1 and liquid chamber 2 with a cleaning solution. However, conventional cleaning methods involve introducing the cleaning solution from the outlet side of the nozzle hole 1 using a cleaning jig, which makes the cleaning process cumbersome and time-consuming, reducing coating productivity.

[0031] Therefore, the coating nozzle 10 in this embodiment is provided with a cleaning liquid supply unit 7 that supplies cleaning liquid to the liquid chamber 2. As a result, the cleaning liquid supplied to the cleaning liquid supply unit 7 by the cleaning liquid delivery mechanism 22 is supplied to the liquid chamber 2, and the cleaning liquid in the liquid chamber 2 is discharged from the nozzle hole 1, allowing cleaning work to be performed by cleaning the nozzle hole 1 and the inside of the liquid chamber 2 with cleaning liquid without using a cleaning jig. Moreover, by performing cleaning work as appropriate during the coating work, the coating work can be continued while repeating coating and cleaning, thereby reducing the maintenance burden.

[0032] Here, between the cleaning operation and the resumption of the coating operation (for example, immediately before starting the coating operation), it is necessary to drain the cleaning liquid remaining in the liquid chamber 2 and nozzle hole 1 from the nozzle hole 1 and refill the liquid chamber 2 and nozzle hole 1 with paint. At this time, if the cleaning liquid introduced into the liquid chamber 2 during the cleaning operation enters the paint supply unit 3, the cleaning liquid will mix with the paint in the paint supply unit 3. In this case, during the paint refilling operation, it becomes necessary to drain not only the cleaning liquid in the liquid chamber 2 and nozzle hole 1, but also the paint in the paint supply unit 3 that has been mixed with the cleaning liquid, from the nozzle hole 1. This results in unnecessary consumption of paint.

[0033] In this embodiment, a needle valve 4 is used as an opening / closing unit that opens and closes the paint inlet 2a of the liquid chamber 2, serving as a switching unit to switch whether or not paint can be discharged from the nozzle hole 1. With this configuration, during cleaning operations, the paint inlet 2a of the liquid chamber 2 can be closed using the needle valve 4, preventing the cleaning liquid supplied from the cleaning liquid supply unit 7 to the liquid chamber 2 from entering the paint supply unit 3. Therefore, no mixing of cleaning liquid with the paint in the paint supply unit 3 occurs, and during paint filling operations, only the cleaning liquid in the liquid chamber 2 and the nozzle hole 1 needs to be discharged from the nozzle hole 1. Consequently, unnecessary consumption of paint can be suppressed.

[0034] In particular, in this embodiment, a needle valve 4 is used to switch whether or not paint can be discharged from the nozzle hole 1 in order to prevent cleaning fluid from entering the paint supply unit 3 during cleaning. Therefore, there is no need to provide a new configuration to prevent cleaning fluid from entering the paint supply unit 3 during cleaning.

[0035] It should be noted that the configuration for preventing cleaning fluid from entering the paint supply unit 3 during cleaning is not limited to this. For example, in this embodiment, as described above, the paint supply mechanism 21 and the cleaning fluid supply mechanism 22 are configured to perform fluid supply operations independently of each other. With this configuration, during cleaning, the paint supply mechanism 21 can be stopped to prevent backflow of paint, thereby preventing the cleaning fluid supplied from the cleaning fluid supply unit 7 to the liquid chamber 2 from entering the paint supply unit 3.

[0036] In particular, in the liquid chamber 2 of this embodiment, by positioning the cleaning liquid inlet 2b closer to the nozzle hole 1 than the paint inlet 2a, the cleaning liquid supplied from the cleaning liquid inlet 2b to the liquid chamber 2 during cleaning is less likely to move to the paint inlet 2a, thereby suppressing the mixing of cleaning liquid into the paint supply unit 3.

[0037] Furthermore, it is preferable that the paint inlet 2a and the cleaning fluid inlet 2b be located close together. In this embodiment, during the cleaning operation, the needle valve 4 is in the closed position, and the tip of the needle valve 4 protrudes from the paint inlet 2a into the liquid chamber 2. Therefore, by arranging the paint inlet 2a and the cleaning fluid inlet 2b close together, it becomes possible to clean the tip of the needle valve 4 protruding from the paint inlet 2a with the cleaning fluid flowing into the liquid chamber 2 from the cleaning fluid inlet 2b.

[0038] Furthermore, in the coating nozzle 10 of this embodiment, as shown in Figure 4, a circulation path 8 for circulating the paint may be provided in the paint supply unit 3. In this case, by connecting a return channel to the paint supply unit 3 to the outlet of the circulation path 8 of the coating nozzle 10, it becomes possible to circulate the paint in the paint supply unit 3. By circulating the paint when paint is not being discharged from the nozzle hole 1, separation and sedimentation of paint components can be suppressed, making it possible to use paints that are prone to component separation or sedimentation, thereby broadening the range of paint types that can be used with this coating nozzle 10. Paint circulation can be achieved, for example, by circulating the paint using energy applied from a gear pump, air pump, etc., while the paint inlet 2a of the liquid chamber 2 is closed with a needle valve 4.

[0039] Next, an example of a coating apparatus using the coating nozzle 10 in this embodiment will be described. Figure 5 is a schematic diagram showing an example of a coating apparatus 30 using the coating nozzle 10 in this embodiment. There are no particular restrictions on the coating apparatus using the coating nozzle 10 in this embodiment, and it can be suitably used with, for example, spray coating apparatuses and other general nozzle coating apparatuses. In particular, as shown in Figure 5, a coating apparatus 30 is preferred in which a coating object W, such as a cylindrical member or a belt-shaped member, is held in a holder 31 which is a rotating part, and paint is discharged from the coating nozzle 10 onto the coating object W on the holder 31 which is rotated by a motor 32 to perform the coating work. This coating apparatus 30 is preferred in that it is easy to control the uniformity of the coating film and the coating cycle time.

[0040] In the coating apparatus 30 shown in Figure 5, the motor 33 rotates the shaft of the slide unit 34, allowing the coating nozzle 10 mounted on the shaft to move along the rotation axis of the holder 31. This makes it easier to maintain uniformity of the coating film even on objects W with a wide coating width.

[0041] The above is just one example; each of the following embodiments produces its own unique effects. [First aspect] The first embodiment is a coating nozzle 10 having a nozzle hole 1 from which liquid paint is discharged, a liquid chamber 2 communicating with the nozzle hole, a paint supply unit 3 that supplies liquid paint to the liquid chamber, and a switching unit (for example, a needle valve 4) that switches whether or not the liquid paint is discharged from the nozzle hole, characterized in that a cleaning liquid supply unit 7 is provided to supply cleaning liquid to the liquid chamber. To prevent paint clogging in the nozzle holes and liquid chambers of coating nozzles, cleaning the nozzle holes and liquid chambers with a cleaning solution is an effective method. However, conventional cleaning methods using a cleaning solution involve introducing the cleaning solution from the outlet side of the nozzle hole using a cleaning jig, which makes the cleaning process complicated and time-consuming, reducing coating productivity. In this embodiment, a cleaning liquid supply unit is provided to supply cleaning liquid to the liquid chamber, so that cleaning liquid can be introduced into the liquid chamber and nozzle holes and cleaning can be performed without using a cleaning jig. Therefore, the time required for cleaning can be shortened and the decrease in coating productivity can be suppressed compared to when cleaning is performed using a cleaning jig.

[0042] [Second aspect] The second embodiment is characterized in that, in the first embodiment, the nozzle component 12, including the discharge-side opening of the nozzle hole, is configured to be replaceable with respect to the main body. This makes it easier to maintain (clean, etc.) the nozzle holes and to change the shape and dimensions of the nozzle holes according to the coating application.

[0043] [Third aspect] The third embodiment is characterized in that, in the first or second embodiment, the cleaning liquid inlet 2b of the liquid chamber to which the cleaning liquid is supplied from the cleaning liquid supply unit is located closer to the nozzle hole than the paint inlet 2a of the liquid chamber to which the liquid paint is supplied from the paint supply unit. According to this, the cleaning liquid supplied from the cleaning liquid inlet 2b to the liquid chamber 2 during the cleaning process is less likely to move to the paint inlet 2a, thereby suppressing the mixing of cleaning liquid into the paint supply unit 3.

[0044] [Fourth aspect] The fourth embodiment is characterized in that, in any of the first to third embodiments, the switching unit is an opening / closing unit (for example, a needle valve 4) that opens and closes the paint inlet 2a of the liquid chamber to which liquid paint is supplied from the paint supply unit. After the cleaning process, before resuming the coating process, it is necessary to drain the cleaning solution remaining in the liquid chamber and nozzle holes through the nozzle holes and then refill the liquid chamber and nozzle holes with paint. However, if the cleaning solution introduced into the liquid chamber during the cleaning process enters the paint supply unit, the cleaning solution will mix with the paint in the paint supply unit. In this case, during the paint refilling process, it becomes necessary to drain not only the cleaning solution in the liquid chamber and nozzle holes, but also the paint in the paint supply unit that has been mixed with the cleaning solution, through the nozzle holes. This results in unnecessary consumption of paint. In this embodiment, an opening / closing unit is used as a switching unit to switch whether or not liquid paint can be discharged from the nozzle hole. This unit opens and closes the paint inlet of the liquid chamber, which is supplied with liquid paint from the paint supply unit. As a result, during cleaning operations, by using this opening / closing unit to close the paint inlet of the liquid chamber, it is possible to prevent the cleaning liquid supplied from the cleaning liquid supply unit into the liquid chamber from entering the paint supply unit. Furthermore, since the paint inlet of the liquid chamber can be closed using an opening / closing mechanism to switch whether or not liquid paint can be discharged from the nozzle hole, there is no need to provide a new configuration to prevent the cleaning liquid supplied to the liquid chamber from entering the paint supply section.

[0045] [Fifth aspect] The fifth aspect is characterized in that, in the fourth aspect, the opening and closing section includes a needle valve 4. According to this, the opening and closing mechanism for opening and closing the paint inlet 2a of the liquid chamber can be easily constructed.

[0046] [Sixth aspect] The sixth aspect is characterized in that, in the fifth aspect, it includes a drive unit 5 for driving the needle valve and an intrusion prevention unit (for example, an elastic diaphragm 6) for preventing the liquid paint of the paint supply unit 3 from entering the housing space 11 housing the drive unit. According to this, the intrusion prevention unit prevents the paint in the paint supply unit 3 from entering the containment space 11, thereby suppressing the instability of the drive unit 5's operation due to contact with the paint.

[0047] [Seventh aspect] The seventh aspect is characterized in that, in the sixth aspect, the drive unit drives the needle valve by either electromagnetic drive, piezoelectric element drive, or air drive. According to this, the needle valve can be driven properly.

[0048] [8th aspect] The eighth aspect is characterized in that, in the sixth or seventh aspect, the intrusion prevention portion has solvent resistance to the solvent contained in the liquid paint or the cleaning solution. According to this, the lifespan of the intrusion prevention part can be extended, and stable operation can be achieved over a long period of time.

[0049] [Ninth aspect] The ninth aspect is characterized in that, in any of the first to eighth aspects, the opening dimensions of the nozzle hole are such that the minimum dimension is 20 μm or more and the maximum dimension is 500 μm or less. This method suppresses the clogging of the nozzle holes with foreign matter while also preventing the deterioration of uneven coating due to the nozzle holes being too large.

[0050] [Tenth aspect] The tenth embodiment is characterized in that, in any of the first to ninth embodiments, the paint supply unit has a circulation path 8 for circulating the liquid paint. According to this method, circulating the paint can suppress the separation and sedimentation of paint components. As a result, it becomes possible to use paints that are prone to component separation or sedimentation, thereby broadening the range of paint types that can be used with this coating nozzle.

[0051] [Aspect 11] The eleventh embodiment is a coating apparatus characterized by comprising a coating nozzle according to any of the first to tenth embodiments. According to this embodiment, it is possible to provide a coating apparatus that can shorten the cleaning time and suppress a decrease in coating productivity.

[0052] [Twelfth aspect] The twelfth embodiment is characterized in that, in the eleventh embodiment, it has a rotating part (for example, a holder 31) for rotating the object to be coated, and liquid paint is discharged from the nozzle hole onto the object to be coated W which is being rotated by the rotating part. According to this embodiment, it is possible to provide a coating apparatus that allows for easy control of coating film uniformity and coating cycle time. [Explanation of Symbols]

[0053] 1: Nozzle hole 2:Liquid chamber 2a:Paint inlet 2b: Cleaning solution inlet 3:Paint supply section 4: Needle valve 5: Drive unit 6: Elastic diaphragm 7: Cleaning fluid supply unit 8:Circulation path 10: Coating nozzle 11: Containment space 12: Nozzle parts 21: Liquid delivery mechanism for paints 22: Fluid delivery mechanism for cleaning solution 30: Coating equipment 31: Holder 32,33: Motor 34: Slide Unit W: Object to be coated [Prior art documents] [Patent Documents]

[0054] [Patent Document 1] Patent No. 4123897

Claims

1. A nozzle hole from which liquid paint is dispensed, A liquid chamber communicating with the nozzle hole, A paint supply unit that supplies liquid paint to the liquid chamber, To switch whether or not the liquid paint can be discharged from the nozzle hole, a needle valve is provided to open and close the paint inlet of the liquid chamber from which the liquid paint is supplied from the paint supply unit, A coating nozzle having a cleaning liquid supply unit that supplies cleaning liquid to the liquid chamber, The needle valve is configured to close the paint inlet with its tip protruding from the paint inlet into the liquid chamber, The coating nozzle is characterized in that the cleaning liquid supply unit supplies cleaning liquid to the liquid chamber so that the tip of the needle valve protruding from the paint inlet is cleaned.

2. In the coating nozzle according to claim 1, A coating nozzle characterized in that the nozzle component, including the discharge-side opening of the nozzle hole, is configured to be replaceable with respect to the coating nozzle body.

3. In the coating nozzle according to claim 1, A coating nozzle characterized in that the cleaning liquid inlet of the liquid chamber, to which the cleaning liquid is supplied from the cleaning liquid supply unit, is located closer to the nozzle hole than the paint inlet.

4. In the coating nozzle according to Claim 1, A drive unit for driving the needle valve, A coating nozzle characterized by having an intrusion prevention part that prevents the liquid paint from the paint supply part from entering the housing space that houses the drive part.

5. In the coating nozzle according to claim 4, The coating nozzle is characterized in that the drive unit drives the needle valve by either electromagnetic drive, piezoelectric element drive, or air drive.

6. In the coating nozzle according to claim 4, The coating nozzle is characterized in that the intrusion-blocking portion has solvent resistance to the solvent contained in the liquid paint or the cleaning solution.

7. In the coating nozzle according to claim 1, A coating nozzle characterized in that the opening dimensions of the nozzle hole are such that the minimum dimension is 20 μm or more and the maximum dimension is 500 μm or less.

8. In the coating nozzle according to claim 1, The coating nozzle is characterized in that the paint supply unit has a circulation path for circulating the liquid paint.

9. A coating apparatus characterized by comprising a coating nozzle according to any one of claims 1 to 8.

10. In the coating apparatus according to claim 9, It has a rotating part that rotates the object to be coated, A coating apparatus characterized by discharging liquid paint from the nozzle hole onto an object to be coated that is being rotated by the aforementioned rotating part.

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