COATING NOZZLE AND COATING APPARATUS

A coating nozzle includes: a nozzle hole from which a liquid paint is discharged in a liquid discharge direction; a liquid chamber communicating with the nozzle hole: a paint supply channel communicating with the liquid chamber, the paint supply channel configured to supply the liquid paint to the liquid chamber; a cleaning-liquid supply channel communicating with the liquid chamber, the cleaning-liquid supply channel configured to supply a cleaning liquid to the liquid chamber: and a switching section configured to selectively switch communication and non-communication between the paint supply channel and the liquid chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is based on and claims priority pursuant to 35 U.S.C. §119(a) to Japanese Patent Application No. 2022-069307. filed on Apr. 20, 2022, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.

BACKGROUND

Technical Field

Embodiments of the present disclosure relate to a coating nozzle and a coating apparatus.

Related Art

Coating nozzles provided with a nozzle hole, a liquid chamber, a paint supply unit, and a switching section have been developed. In such coating nozzles, the nozzle hole discharges liquid paint, and the liquid chamber communicates with the nozzle hole. Further, the paint supply unit supplies liquid paint to the liquid chamber, and the switching section enables or disables the nozzle hole to discharge the liquid paint.

An inkjet nozzle (or a coating nozzle) in the background art, for example, opens and closes the nozzle hole using a needle valve (i.e., the switcher) in the ink chamber (or the liquid chamber) communicating with the nozzle hole, so as to switch between enabling or disabling discharge of ink (i.e., liquid paint) from the nozzle hole.

SUMMARY

An embodiment of the present disclosure provides a coating nozzle includes: a nozzle hole from which a liquid paint is discharged in a liquid discharge direction; a liquid chamber communicating with the nozzle hole: a paint supply channel communicating with the liquid chamber, the paint supply channel configured to supply the liquid paint to the liquid chamber; a cleaning-liquid supply channel communicating with the liquid chamber, the cleaning-liquid supply channel configured to supply a cleaning liquid to the liquid chamber; and a switching section configured to selectively switch communication and non-communication between the paint supply channel and the liquid chamber.

Embodiments of the present disclosure enable a shorter cleaning time and reduce or prevent a decrease in coating productivity by injecting a cleaning liquid into the liquid chamber and the nozzle hole to clean the coating nozzle without the use of a cleaning tool.

DETAILED DESCRIPTION

A coating nozzle for use in a coating apparatus according to an embodiment of the present disclosure is described below.

FIGS.1and2are illustrations of a coating nozzle10according to an embodiment of the present disclosure.

The coating nozzle10according to an embodiment includes a nozzle hole1, from which a liquid paint (hereinafter simply referred to as paint or coating material) is discharged in a liquid discharge direction, a liquid chamber2communicating with the nozzle hole1, and a paint supplier3as a paint supply channel that supplies paint to the liquid chamber2. Further, the coating nozzle10further includes a needle valve4(or an opening and closing section) that opens and closes a paint inlet2aof the liquid chamber2. The needle valve4servesas a switching section that enables or disables the discharge of coating material from the nozzle hole1(i.e., the switching section selectively switches communication and non-communication between the paint supply channel and the liquid chamber). The coating nozzle10still further includes a driver5that drives the needle valve4and an elastic diaphragm6(or a blocker) that blocks the paint of the paint supplier3from entering an accommodating space11accommodating the driver5. Furthermore, the coating nozzle10according to an embodiment includes a cleaning-liquid supplier7as a cleaning-liquid supply channel that supplies a cleaning liquid to the liquid chamber2.

In the coating nozzle10according to an embodiment of the present disclosure, a paint feeding mechanism21is connected to the paint supplier3, and a cleaning-liquid feeding mechanism22is connected to the cleaning-liquid supplier7. The paint feeding mechanism21and the cleaning-liquid feeding mechanism22feed the respective liquids, independently of each other. In this configuration, the operation of feeding the paint from the paint feeding mechanism21to the paint supplier3is executed while the operation of feeding the cleaning liquid from the cleaning-liquid feeding mechanism22to the cleaning-liquid supplier7is stopped. Conversely, the operation of feeding the paint from the cleaning-liquid feeding mechanism22to the cleaning-liquid supplier7is executed while the operation of feeding the cleaning liquid from the paint feeding mechanism21to the paint supplier3is stopped.

The paint feeding mechanism21and the cleaning-liquid feeding mechanism22are not particularly limited, but a syringe pump, a pressurized tank, or the like can be suitably used. However, when the landing efficiency of the paint discharged from the nozzle hole1is extremely high, the paint feeding mechanism21is preferably controlled to supply a tiny amount of paint.

In the coating nozzle10of the present embodiment, when the paint is not discharged from the nozzle hole1, as illustrated inFIG.1, the needle valve4is moved to a closed position to close the paint inlet2aof the liquid chamber2so as to disable the supply of the paint from the paint supplier3to the liquid chamber2. When the paint is discharged from the nozzle hole1, as illustrated inFIG.2, the needle valve4is moved to an open position to open the paint inlet2aof the liquid chamber2so as to enable the supply of the paint from the paint supplier3to the liquid chamber2. This configuration controls the driver5to switch or move the position of the needle valve4between the open position and the closed position to enable or disable the paint fed from the paint feeding mechanism21to the paint supplier3to be discharged from the nozzle hole I through the liquid chamber2.

The nozzle hole1according to an embodiment of the present disclosure discharges the paint within the liquid chamber2during the coating operation, and discharges the paint or the cleaning liquid within the liquid chamber2during the cleaning operation. The shape of the cross section of the nozzle hole1. which is orthogonal to the discharge direction of the nozzle hole1is appropriately selected in consideration of the characteristics of the coating object and the paint. A typical shape of the cross-section of the nozzle hole1is preferably a circular shape or a quadrangular shape in consideration of the ease of processing of the nozzle hole1.

The nozzle hole1preferably has a minimum opening dimension of 20 µm or more and a maximum opening dimension of 500 µm or less to reduce the non-uniformity in coating film and shorten a coating tact time. When the opening of the nozzle hole1has a circular shape, for example, its diameter is preferably 20 µm or more and 500 µm or less. When the opening of the nozzle hole1has a rectangular shape, for example, its short side is preferably 20 µm or more, and its diagonal line is 500 µm or less. A nozzle hole having a minimum opening dimension of less than 20 µm may become clogged with foreign matter, and a nozzle hole having a maximum opening dimension of more than 500 µm may more likely cause the non-uniformity in coating film to deteriorate.

The nozzle hole1may be directly formed in a body of the coating nozzle. Alternatively, a nozzle part including the outlet opening of the nozzle hole1may be fixed to the coating nozzle main body in an integral manner. However, as illustrated inFIG.3, a nozzle part12including the opening (or an outlet opening) of the nozzle hole1may be attached to or detachable from the body of the body of the coating nozzle for ease of maintenance. The body includes the paint supplier3(the paint supply channel), the cleaning-liquid supplier7(the cleaning-liquid supply channel), and the needle valve4(the switching section). Such an attachable or detachable nozzle part12facilitates the maintenance of the nozzle hole1(e.g., cleaning) or a change in the shape or dimension of the nozzle hole1according to the coating application.

The material of an element forming the nozzle hole1is not limited, but is preferably a material having corrosion resistance to a paint or a cleaning liquid to be used.

The coating material for the coating nozzle10according to an embodiment of the present disclosure is not particularly limited. However, the characteristics such as the viscosity and the solid content concentration are appropriately selected according to the opening dimension of the nozzle hole1and the amount of paint discharged from the nozzle hole1during the coating operation. The nozzle hole1with a small opening dimension may fail to discharge paint having a high viscosity or have difficulty in stably discharging paint having a high viscosity. The solid content concentration and viscosity of the paint may be reduced to deal with such a situation. The reduction in the solid content concentration and viscosity of the paint (coating material) allows stable discharge from the nozzle hole1, but causes disadvantages: more amount of paint to be discharged to obtain desired coating thickness; a deterioration in the non-uniformity in film thickness due to an increase in a wet film thickness of an object to be coated; and a longer dry-to-touch time.

Fine particles may be contained in the coating material, but if the fine particles are larger than the opening dimension of the nozzle hole1, discharge failure is likely to occur, and discharge failure may not be recovered by washing. For this reason, sufficient consideration is to be given to the selection of the particle diameter of the fine particles.

To prevent or reduce clogging of the nozzle hole or the liquid chamber with liquid coating material, or paint in the coating nozzle10, cleaning the nozzle hole and the liquid chamber with a cleaning liquid is effective. However, a typical cleaning method involves injecting a cleaning liquid into the outlet of the nozzle hole using a cleaning tool. The typical cleaning method causes complicated and time-consuming cleaning operation and lowers coating productivity.

By contrast, embodiments of the present disclosure include a cleaning-liquid supplier for supplying a cleaning liquid to the liquid chamber and involve injecting a cleaning liquid into the liquid chamber and the nozzle hole without using a cleaning tool.

There are no particular restrictions on the cleaning liquid that can be used in the coating nozzle10according to an embodiment of the present disclosure, but in general, a cleaning liquid using a solvent that is the same as or more soluble than the solvent contained in the coating material is desirable.

The paint supplier3includes a channel for conveying paint fed from the paint feeding mechanism21to the liquid chamber2. As illustrated inFIGS.1and2, the downstream end of the paint supplier3connected to the paint inlet2aof the liquid chamber2along a channel from the paint feeding mechanism21to the paint inlet2ais tapered. The front-end portion of the needle valve4is arranged in the paint supplier3. As illustrated inFIG.1, the leading end of the needle valve4is moved to the closed position to close the downstream end of the paint supplier3(i.e., the paint inlet2aof the liquid chamber2) so as to block paint from being supplied from the paint supplier3to the liquid chamber2. As illustrated inFIG.2, the leading end of the needle valve4is moved to the open position to open the downstream end of the paint supplier3(i.e., the paint inlet2aof the liquid chamber2) so as to enable the paint to be supplied from the paint supplier3to the liquid chamber2.

The driver5that drives the needle valve4presses the needle valve4toward the paint inlet2aof the liquid chamber2A using a biasing force of a biasing member such as a spring, to move the needle valve4to the closed position. To move the needle valve4to the open position, the driver5includes a driving mechanism that moves the needle valve4backward (i.e., in an upstream direction) to the open position using a force exceeding the biasing force of the biasing member.

The driving mechanism is not particularly limited, but is preferably electromagnetically driven or pneumatically driven in view of responsiveness, safety, and convenience.

The electromagnetic drive mechanism may be, for example, a solenoid. A fixed iron core of a solenoid is arranged facing a magnetic body at a rear end of a needle valve, and a current is applied to the solenoid to generate a magnetic field. This causes the rear end of the needle valve to be attracted to the fixed iron core to pull down the needle valve4backward and position it at the open position. Such a driving mechanism can precisely control the opening and closing operation of the paint inlet2ausing the needle valves4by controlling the electric current supplied to the solenoid. This enables control of the discharge pattern and the discharge amount of paint discharged from the nozzle holes1with high accuracy.

The pneumatically-driven mechanism is suitable for placing a high priority on safety and convenience. In such a drive mechanism, the pressure of the compressed air is used to drive the needle valve to move it rearward.

The driving mechanism of the driver5may be driven by a piezoelectric element. In the driving mechanism using the piezoelectric element, the needle valve4with its rear end fixed to the piezoelectric element is moved between the close position and the open position using the distortion or displacement of the piezoelectric element in response to applied voltage. This enables a high-speed control of the position of the needle valve4and thus allows control of the open-close operation of the paint inlet2awith high response.

In the coating nozzle10according to an embodiment of the present disclosure, the elastic diaphragm6is disposed to divide the paint supplier3in which the front-end portion of the needle valve4and the paint are included, from the accommodating space11accommodating the driver5attached to the rear-end portion of the needle valve4. The elastic diaphragm6is provided to close a gap between the paint supplier3and the accommodating space11while allowing the needle valve4to move between the closed position and the open position. A pressure produced by the paint feeding mechanism21supplying paint to the paint supplier3is applied to the paint in the paint supplier3. Irrespective of the pressure being applied to the paint supplier3, the elastic diaphragm6blocks the paint of the paint supplier3from entering the accommodating space11.

The material of the elastic diaphragm6is preferably selected according to the solvent contained in the paint. Particularly when an organic solvent is used, the elastic diaphragm6made of a solvent-resistant material extends the life of the elastic diaphragm6and achieves a stable driving over a long period of time. Further, the material of the elastic diaphragm6is preferably resistant to a solvent contained in a cleaning liquid, in consideration of the possibility that the cleaning liquid might be mixed into the interior of the paint supplier3.

In the coating process using the coating nozzle10, the paint feeding mechanism21first feeds paint to the paint supplier3with the cleaning-liquid feeding mechanism22deactivated (i.e., the operation of feeding a cleaning liquid from the cleaning-liquid feeding mechanism22to the cleaning-liquid supplier7is stopped). In this state, when positioned at the closed position to close the paint inlet2aof the liquid chamber2after being moved by the driver5, the needle valve4blocks the paint fed from the paint supplier3from being supplied to the liquid chamber2. Thus, the paint is not discharged from the nozzle hole1.

When the needle valve4is positioned at the open position after being moved by the driver5with the paint supplier3filled with the paint, a gap is created between the leading end of the needle valve4and the downstream end of the paint supplier3along the channel from the paint feeding mechanism21to the paint inlet2a. Thus, the paint inlet2aof the liquid chamber2is opened, the paint inlet2abeing connected to the downstream end of the paint supplier3. This allows the paint supplier3to supply its paint to the liquid chamber2through the paint inlet2aand thus enables discharge of the paint from the nozzle hole1communicating with the liquid chamber2.

At this time, since the operation of feeding the cleaning liquid from the cleaning-liquid feeding mechanism22to the cleaning-liquid supplier7is stopped, the cleaning liquid is not supplied from the cleaning-liquid supplier7to the liquid chamber2, and only the paint (coating material) is discharged from the nozzle hole1. In examples as illustrated inFIGS.1to4, a cleaning-liquid inlet2b, from which a cleaning liquid is supplied from the cleaning-liquid supplier7to the liquid chamber2. is designed to be open. In some other examples, the cleaning-liquid inlet2bis provided with a opening and closing section for opening and closing the cleaning-liquid inlet2b. In this case, the cleaning-liquid inlet2bis kept closed by the opening and closing section during discharge of paint from the nozzle hole1. This stably reduces or prevents the cleaning liquid from being mixed into the paint.

At the time when the coating operation is finished, the nozzle hole1and the liquid chamber2have paint adhering to or are filled with paint. If the nozzle hole1and the liquid chamber2are left in such a condition, the paint may be solidified, or the paint component may be precipitated, possibly causing clogging of the nozzle hole1or the liquid chamber2. To prevent or reduce such clogging, the nozzle hole1and the liquid chamber2are cleaned or washed with a cleaning liquid, which is effective. However, a typical cleaning method involves injecting a cleaning liquid into the outlet of the nozzle hole1using a cleaning tool. The typical cleaning method may cause complicated and time-consuming cleaning operation and lower coating productivity.

To deal with such disadvantages, the coating nozzle10according to an embodiment includes a cleaning-liquid supplier7that supplies a cleaning liquid to the liquid chamber2. The cleaning-liquid supplier7supplies a cleaning liquid fed by the cleaning-liquid feeding mechanism22to the liquid chamber2and thus allows the cleaning liquid in the liquid chamber2to be discharged from the nozzle hole1. This enables a cleaning operation involving cleaning the nozzle hole1and the interior of the liquid chamber2with the cleaning liquid without using a cleaning tool. Moreover, since the coating operation can be continued while repeating the coating and the cleaning by appropriately executing the cleaning operation in the middle of the coating operation, it is possible to reduce the maintenance load.

During the period from the cleaning operation to the restart of the coating operation (for example, immediately before the start of the coating operation), a paint filling operation is performed, including causing a cleaning liquid remaining in the liquid chamber2and the nozzle hole1to be discharged therefrom and injecting paint into the liquid chamber2and the nozzle hole1again to make the liquid chamber2and the nozzle hole1filled with the paint. At this time, if the coating nozzle has a configuration that causes the cleaning liquid injected into the liquid chamber2to enter the paint supplier3during the cleaning operation, the cleaning liquid may be mixed into the paint in the paint supplier3. In such a case, both the cleaning liquid in the liquid chamber2and the nozzle hole1and the paint mixed with the cleaning liquid in the paint supplier3are discharged from the nozzle hole1in the paint filling operation. This involves unnecessary consumption of the paint.

The coating nozzle1as illustrated inFIGS.1to4includes the needle valve4(or an opening and closing section) that opens and closes the paint inlet2aof the liquid chamber2. The needle valve4serves as a switching section that selectively enables or disables discharge of coating material from the nozzle hole1. This configuration using the needle valve4closes the paint inlet2aof the liquid chamber2to prevent the cleaning liquid supplied from the cleaning-liquid supplier7to the liquid chamber2from entering the paint supplier3in the cleaning operation. This further prevents mixture of the cleaning liquid and the paint in the paint supplier3and eliminates a process of discharging the paint mixed with the cleaning liquid in the paint supplier3, thus facilitating the paint filling operation that involves discharging only the cleaning liquid within the liquid chamber2and the nozzle hole1. Thus, the coating nozzle according to an embodiment of the present disclosure prevents or reduce unnecessary consumption of the paint.

The coating nozzle10as illustrated inFIGS.1to4particularly features the needle valve4that enables or disables the discharge of paint from the nozzle hole1, i.e., the configuration that prevents mixture of the cleaning liquid into the paint supplier3in the cleaning operation. This configuration eliminates an additional element or structure for preventing the mixture of the cleaning liquid into the paint supplier3in the cleaning operation.

The configuration that prevents the cleaning liquid into the paint supplier3in the cleaning operation is not limited to the above-described configuration. As described above, in the configuration as illustrated inFIGS.1to4, the paint feeding mechanism21and the cleaning-liquid feeding mechanism22feed the respective liquids, independently of each other. This configuration stops the paint feeding mechanism21to prevent the backflow of paint and thus prevents the cleaning liquid fed from the cleaning-liquid supplier7to the liquid chamber2from entering the paint supplier3in the cleaning operation.

In the liquid chamber2according to an embodiment of the present disclosure, the liquid chamber2has paint inlet2a(a first inlet) at which the paint supplier3is connected to the liquid chamber2and the cleaning-liquid inlet2b(a second inlet) at which the cleaning-liquid supplier7is connected to the liquid chamber2. The cleaning-liquid inlet2b(the second inlet) is closer to the nozzle hole1than the paint inlet2a(the first inlet). This arrangement reduces the cleaning liquid fed from the cleaning-liquid inlet2bto the liquid chamber2from being moved to the paint inlet2aand thus prevents or reduces the cleaning liquid from being mixed into the interior of the paint supplier3.

The paint inlet2aand the cleaning-liquid inlet2bare preferably close to each other. In the embodiment illustrated inFIGS.1to4, the needle valve4is at the closed position to have its leading end protruding beyond the paint inlet2ainto the liquid chamber2in the cleaning operation. This arrangement in which the paint inlet2aand the cleaning-liquid inlet2bare close to each other allows the leading end of the needle valve4protruding beyond the paint inlet2ato be washed or cleaned with the cleaning liquid flown into the liquid chamber2from the cleaning-liquid inlet2b.

In the coating nozzle10according to an embodiment as illustrated inFIG.4, the paint supplier3includes a circulation channel8for circulating the paint. In this case, the circulation channel8of the coating nozzle10has an outlet connected to a return channel for returning the paint to the paint supplier3. This configuration allows circulation of the paint within the paint supplier3. Circulating the paint while the operation of discharging the paint from the nozzle hole1is stopped reduces and prevents separation and precipitation of paint component from the paint. This allows the use of paint, from which paint component is likely to separate or precipitate and enables a wider range of kinds of coating materials to be used in the coating nozzle10. The paint (coating material) is circulated using energy applied from, for example, a gear pump or an air pump, with the paint inlet2aof the liquid chamber2closed by the needle valve4.

The following describes a coating apparatus incorporating the coating nozzle10according to an embodiment of the present disclosure.

FIG.5is a diagram of a coating apparatus30incorporating a coating nozzle10according to an embodiment of the present disclosure.

The coating apparatus incorporating the coating nozzle10according to an embodiment of the present disclosure is not limited to the example inFIG.5. For example, the coating apparatus may be a spray coating apparatus or other typical nozzle coating apparatuses. The coating apparatus30as illustrated inFIG.5is particularly preferable, which includes: the coating nozzle10; a holder31as a rotator holding an object W to be coated (e.g., a columnar member and a belt-shaped member) on the holder31: and a motor32configured to rotate the holder31. The coating nozzle10discharges paint onto the object W to be coated in the coating operation. Such a coating apparatus30facilitates control of the uniformity of the coating film and a coating tact time.

The coating apparatus30inFIG.5further includes a slid unit34on the axis of which the coating nozzle10is disposed; and another motor33configured to rotate the axis of the slid unit34to allow the coating nozzle10to move along the axis of rotation of the holder31. This allows the coating film to maintain its uniformity on the object W to be coated having a wide width for coating.

The above-described embodiments are limited examples, and the present disclosure includes, for example, the following aspects having advantageous effects.

A coating nozzle includes: a nozzle hole1from which a liquid paint is discharged in a liquid discharge direction; a liquid chamber2communicating with the nozzle hole1: a paint supply channel (a paint supplier3) communicating with the liquid chamber, the paint supply channel configured to supply the liquid paint to the liquid chamber; a cleaning-liquid supply channel (a cleaning-liquid suppler7) communicating with the liquid chamber, the cleaning-liquid supply channel configured to supply a cleaning liquid to the liquid chamber: and a switching section (e.g., a needle valve4) configured to selectively switch communication and non-communication between the paint supply channel and the liquid chamber.

To prevent or reduce clogging of the nozzle hole or the liquid chamber with liquid coating material, or paint in the coating nozzle, cleaning the nozzle hole and the liquid chamber with a cleaning liquid is effective. However, a typical cleaning method involves injecting a cleaning liquid into the outlet of the nozzle hole using a cleaning tool. The typical cleaning method causes complicated and time-consuming cleaning operation and lowers coating productivity.

By contrast, embodiments of the present disclosure include a cleaning-liquid supplier for supplying a cleaning liquid to the liquid chamber and involve injecting a cleaning liquid into the liquid chamber and the nozzle hole without using a cleaning tool. Embodiments of the present disclosure enable a shorter cleaning time and reduce or prevent a decrease in coating productivity as compared to a cleaning operation using a cleaning tool.

The coating nozzle according to Aspect 1, further includes: a body including: the paint supply channel: the cleaning-liquid supply channel; and the switching section; and a nozzle part12including: the liquid chamber; and the nozzle hole. The nozzle part is attachable to or detachable from the body.

This facilitates the maintenance of the nozzle hole (e.g.. cleaning) or a change in the shape or dimension of the nozzle hole according to the coating application.

The coating nozzle according to Aspect 1 or 2, the liquid chamber has: a first inlet (a paint inlet21) at which the paint supply channel is connected to the liquid chamber; and a second inlet (a cleaning-liquid inlet2b) at which the cleaning-liquid supply channel is connected to the liquid chamber. The second inlet is closer to the nozzle hole than the first inlet in the liquid discharge direction.

This arrangement reduces the cleaning liquid fed from the cleaning-liquid inlet2bto the liquid chamber2from being moved to the paint inlet2aand thus prevents or reduces the cleaning liquid from being mixed into the interior of the paint supplier3.

The coating nozzle according to any one of Aspect 1 to Aspect 3, the switching section (e.g., the needle valve 4) openably closes the first inlet.

During the period from the cleaning operation to the restart of the coating operation, a paint filling operation is performed, including causing a cleaning liquid remaining in the liquid chamber and the nozzle hole to be discharged therefrom and injecting paint into the liquid chamber and the nozzle hole again to fill the paint into the liquid chamber and the nozzle hole. At this time, if the coating nozzle has a configuration that causes the cleaning liquid injected into the liquid chamber to enter the paint supplier during the cleaning operation, the cleaning liquid may be mixed into the paint in the paint supplier. In such a case, both the cleaning liquid in the liquid chamber and the nozzle hole and the paint mixed with the cleaning liquid in the paint supplier are discharged from the nozzle hole in the paint filling operation. This involves unnecessary consumption of the paint.

In this configuration, the coating nozzle includes an opening and closing section that opens and closes the paint inlet of the liquid chamber to which the liquid paint is supplied from the paint supplier. The opening and closing section serves as a switching section that enables or disables discharge of the liquid paint from the nozzle hole.

This configuration using the opening and closing section closes the paint inlet of the liquid chamber to prevent the cleaning liquid supplied from the cleaning-liquid supplier to the liquid chamber from entering the paint supplier in the cleaning operation.

Further, the opening and closing section that enables or disables the discharge of the liquid paint from the nozzle hole allows the paint inlet of the liquid chamber to be closed. This eliminates the use of an additional configuration that prevents the cleaning liquid fed to the liquid chamber from entering the paint supplier.

The coating nozzle according to Aspect 4, the switching section includes a needle valve 4 that openably closes the first inlet.

This configuration enables a simple opening and closing section that opens and closes the paint inlet2aof the liquid chamber.

The coating nozzle according to Aspect 5, further includes: a driver5in an accommodating space11, the driver configured to drive the needle valve: and a blocker (e.g., an elastic diaphragm6) attached to the needle valve. The blocker blocks the liquid paint in the paint supply channel (the paint supplier3) from entering the accommodating space.

In this configuration, the blocker prevents the paint in the paint supplier3from entering the accommodating space11, thus preventing or reducing an unstable operation of the driver5due to contact of the driver5with the paint.

The coating nozzle according to Aspect 7, the driver electromagnetically, pneumatically, or piezoelectrically drives the needle valve.

This enables an appropriate driving of the needle valve.

The coating nozzle according to Aspect 6 or 7, the blocker is resistant to a solvent contained in the liquid paint or the cleaning liquid.

This configuration extends the life of the blocker and achieves a stable driving over a long period of time.

The coating nozzle according to any one of Aspect 1 to Aspect 8, the nozzle hole has: a minimum opening dimension of 20 µm or more; and a maximum opening dimension of 500 µm or less.

This configuration prevents or reduces clogging of the nozzle hole with foreign substance as well as a deterioration in the non-uniformity of the coating film due to an excessively large opening of the nozzle hole.

The coating nozzle according to any one of Aspect 1 to Aspect 9, the paint supply channel includes a circulation channel, from which the liquid paint is discharged, to circulate the liquid paint.

This configuration prevents or reduces paint component from separating or precipitating from the paint by circulating the paint. This allows the use of paint from which paint component is likely to separate or precipitate, and enables a wider range of kinds of coating materials to be used in the coating nozzle.

A coating apparatus includes: the coating nozzle according to Aspect 1; and a slider including an axis to which the coating nozzle is attached, the slider configured to move the coating nozzle in an axial direction of the axis.

This configuration provides a coating apparatus that enables a shorter cleaning time and reduces or prevents a decrease in coating productivity.

In Aspect 11, the coating apparatus further includes a rotator (e.g., a holder31) configured to rotate an object W. The coating nozzle is configured to discharge the liquid paint to the object rotated by the rotator to coat the object with the liquid paint.

This configuration provides a coating apparatus that facilitates control of the uniformity of the coating film and a coating tact time.

The coating nozzle according to Aspect 1, the first inlet is in a vicinity of the second inlet. The needle valve has a leading end to close the first inlet at a closed position. The leading end of the needle valve at the closed position protrudes into an interior of the liquid chamber from the first inlet.

The coating nozzle according to Aspect 11, the cleaning liquid supplied from the cleaning-liquid supply channel is supplied from the second inlet to the liquid chamber in a state where the needle valve closes the first inlet.