JP2006347000A - Liquid droplet delivering device with cleaning function and method of cleaning liquid droplet delivering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet delivering device which does not require a large space, does not impose a large load on itself and can clean a liquid droplet delivering nozzle easily and in a short time, and a method of cleaning the device. <P>SOLUTION: An ultrasonic vibrator is fitted to a cap mounted on a delivering head in order to prevent a delivering liquid from vaporizing. Next, the cap is set to cover the delivering nozzle in such a state that the delivering nozzle and the cap are internally filled with the liquid, and the delivering nozzle and a nozzle plate are cleaned by emitting an ultrasonic wave with the help of the ultrasonic vibrator. After that, and the ultrasonic wave is emitted from the ultrasonic vibrator. Further, it is also possible to increase the cleaning effect by emitting the ultrasonic wave from a piezoelectric element for discharging the liquid droplet, preferably in resonance with the ultrasonic wave from the ultrasonic vibrator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a droplet discharge device having a cleaning function and a cleaning method for the droplet discharge device. In particular, the present invention relates to a droplet discharge device having a function of cleaning the inside of a nozzle hole of a discharge nozzle and a nozzle plate used in an inkjet device, and a cleaning method thereof.

The liquid ejection device usually passes through a plurality of droplet ejection nozzles provided in the droplet ejection head.
A desired liquid such as ink is ejected onto the object due to the fluctuation of the piezoelectric element. The liquid discharged from the droplet discharge device is usually one obtained by dissolving or dispersing a desired component such as a pigment in a solvent. For this reason, if the droplet discharge nozzle is left unused for a long time, the solvent of the discharge liquid evaporates, and components such as pigments thicken or solidify in the nozzle holes and on the nozzle plate. . Even if the droplet discharge device is operated, the discharge liquid is not always discharged from all the discharge nozzles. For this reason, solidification or thickening of the discharge liquid occurs in the nozzle holes and on the nozzle plate where the discharge liquid does not circulate for a long time or has a low distribution frequency. The solidified product of the discharged liquid thus generated causes nozzle clogging and droplet bending.

For this reason, the droplet discharge device normally prevents evaporation of the solvent from the discharge nozzle port, that is, prevents solidification and thickening of the discharge liquid, prevents dust from adhering to the discharge nozzle, and discharge liquid adhering to the nozzle plate. For the purpose of removal or the like, a cap that covers the droplet discharge nozzle (droplet discharge head surface) is provided (see, for example, Patent Document 1). Normally, this cap is automatically attached to the discharge nozzle when the operation of the droplet discharge device is stopped, and prevents evaporation of the solvent and adhesion of dust. Further, an absorbent body can be arranged in the cap, and the discharged liquid adhering to the nozzle plate when the cap is mounted can be sucked and removed.

However, when the droplet discharge device is in operation or not in use for a long period of time, the evaporation of the solvent cannot be suppressed, and it is difficult to completely prevent the generation of a solidified discharge liquid. As a method of removing the solidified product of the discharge liquid generated in the droplet discharge nozzle hole or on the nozzle plate,
For example, there is a method in which a solidified product is dissolved in its main solvent. As another method, as in Patent Document 1, a suction device is connected to the cap, and the solidified or thickened substance of the discharge liquid adhering to the discharge nozzle is removed by suction, or the discharge liquid or its main solvent is discharged. There is a method of dissolving or peeling a solidified product or a thickened product by suction through a nozzle.

In addition, as an apparatus for cleaning the discharge nozzle, an apparatus using ultrasonic waves is known. For example, in the cleaning apparatus described in Patent Document 2, a nozzle hole of an inkjet nozzle is brought into contact with water droplets supplied onto a vibration plate of an ultrasonic vibrator, and the vibration plate is vibrated by the ultrasonic vibrator to form a nozzle hole. We are cleaning.

JP 2001-287374 A JP 7-329310 A

Since the discharge nozzles of the droplet discharge device are fine and usually installed in plural, it is difficult to manually remove the solidified product of the discharge liquid adhering to the discharge nozzles one by one, and the efficiency is also high. bad. Therefore, it is preferable to remove the solidified substance adhering to the discharge nozzle by using the discharge liquid itself or its main solvent as in the method described above.

However, in the method of dissolving the solidified product by immersing it in the discharge liquid or the main solvent, it takes much time to dissolve all the solidified product, and the efficiency is poor. Moreover, the solidified substance with poor solubility cannot be completely removed by just dipping.

Further, in the method of sucking the discharge liquid or the main solvent from the discharge port, a large amount of the discharge liquid or solvent is consumed, so that there is a problem in terms of cost. Further, a solidified product having poor solubility cannot be easily dissolved or peeled off even when sucked.

Ultrasound is useful for cleaning the solidified material. However, as in the cleaning device described in Patent Document 2, newly providing an ultrasonic cleaning device in the droplet discharge device makes the droplet discharge device large. So
It is not preferable. Further, in the cleaning device described in Patent Document 2, since a very small amount of water is used for ultrasonic cleaning, the load on the device itself is large due to reflection of ultrasonic waves and the device may be damaged.

The object of the present invention is not to require a large space and without placing a heavy burden on itself.
It is another object of the present invention to provide a droplet discharge device and a cleaning method thereof that can clean the droplet discharge nozzle in a short time and easily.

The present invention makes it possible to save space in a droplet discharge device having an ultrasonic cleaning function and to discharge a droplet by utilizing a cap of a component normally provided in the droplet discharge device as a liquid tank and an ultrasonic transmission source. Improved nozzle cleaning efficiency.

According to the basic form of the first aspect of the present invention, the liquid droplet discharge apparatus includes a discharge nozzle that discharges a liquid droplet and a cap that covers the discharge port of the discharge nozzle, and the cap includes an ultrasonic vibrator. Providing the device.

According to a preferred form of the basic form of the first aspect, the droplet discharge device of the present invention has a discharge head including a plurality of discharge nozzles, and the cap is large enough to cover a plurality of nozzle openings of the discharge nozzles. The portion that comes into contact with the ejection head has flexibility.

According to a preferred form of each of the above forms, the droplet discharge device of the present invention includes a piezoelectric element that can oscillate ultrasonic waves as means for discharging droplets from the discharge nozzle.

According to a preferable form of each of the above embodiments, the droplet discharge device of the present invention includes the cap liquid supply device that fills the recess in the cap with the liquid and the suction device that sucks the liquid from the recess.

According to the preferable form of each said form, a liquid is a liquid which can melt | dissolve the deposit | attachment adhering to the discharge nozzle.

  According to the preferable form of said each form, a cap is equipped with the heating apparatus which heats a liquid.

According to the basic form of the second aspect of the present invention, the liquid is filled in the concave portion of the cap that covers the discharge port of the discharge nozzle that discharges the droplet, and the cap is covered with the discharge nozzle. A cleaning method for a droplet discharge device, including a cleaning preparation step for cleaning preparation and an oscillation / cleaning step for cleaning an ejection nozzle by oscillating ultrasonic waves from an ultrasonic vibrator disposed on a cap. .

According to a preferred form of the basic form, the method for cleaning a droplet discharge device of the present invention further includes a step of vibrating the piezoelectric element between the oscillation and cleaning steps.

According to a preferred form of the above aspect, the method for cleaning a droplet discharge device of the present invention further includes a step of resonating the ultrasonic wave oscillated from the ultrasonic vibrator and the ultrasonic wave oscillated from the piezoelectric element.

According to the preferable form of each said form, a cleaning preparation process includes the filling process which fills a recessed part with a liquid, and the covering process which covers a cap on a discharge nozzle after a filling process. According to another preferred embodiment, the cleaning preparation step includes a covering step for covering the cap on the discharge nozzle, and a filling step for filling the recess with the liquid after the covering step.

According to a preferred form of each of the above embodiments, the cleaning preparation step is performed by increasing the liquid level position of the liquid supply tank that supplies the liquid to the discharge nozzle relative to the position of the liquid surface in the discharge nozzle hole. And a step of filling the inside of the discharge nozzle hole with liquid up to at least the discharge port of the discharge nozzle. According to another preferred embodiment, the cleaning preparation step includes the position of the liquid surface in the discharge nozzle hole,
It includes a step of filling the inside of the discharge nozzle hole with liquid up to at least the discharge port of the discharge nozzle by lowering relative to the liquid surface position of the discharge liquid tank that supplies the liquid to the discharge nozzle.

According to a preferred form of each of the above embodiments, the method for cleaning a droplet discharge device of the present invention further includes a step of sucking and removing at least the liquid in the discharge nozzle and the cap after the oscillation / cleaning step.

According to the preferable form of each said form, the cleaning method of the droplet discharge apparatus of this invention uses the liquid which can melt | dissolve the deposit | attachment adhering to the discharge nozzle as a liquid.

According to the apparatus and method of the present invention, since cleaning is performed using ultrasonic waves, solidified substances and deposits that cannot be easily dissolved or peeled off only by immersion or suction with a solvent or the like can be easily removed. In addition, by resonating the piezoelectric element that discharges the liquid droplets, the cleaning effect can be enhanced with small energy. Furthermore, since the discharge nozzle is cleaned using a cap that covers the droplet discharge head, the inside of the nozzle hole and the nozzle plate surface can be cleaned simultaneously. Further, since a large amount of discharge liquid or solvent is not consumed as in the case of suction cleaning, cleaning costs and waste can be reduced.

Furthermore, according to the apparatus of the present invention, instead of separately providing a dedicated apparatus for cleaning the discharge nozzle,
Since the configuration and components that the droplet discharge device normally has are utilized, the droplet discharge device can be provided with a cleaning function for the discharge nozzle without increasing the size. Since the cap is filled with the liquid, the burden on the ultrasonic vibrator and the like can be reduced, and ultrasonic cleaning can be performed efficiently.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a droplet discharge head portion that covers a cap in the droplet discharge apparatus of the present invention. The cap 4 is used as a cover for the droplet discharge head 1 when the operation of the droplet discharge device is stopped in order to prevent evaporation of the solvent of the discharge liquid and adhesion of dust in the droplet discharge nozzle 2. The ejection head 1 has a plurality of ejection nozzles 2, and the cap can cover one ejection head 1, that is, the plurality of ejection nozzles 2 arranged in the ejection head 1. The size and number of caps 4 can be appropriately set according to the size of the ejection head 1 and the number of ejection nozzles 2. Any material can be used for the cap 4 as long as it can transmit ultrasonic waves and can hold a liquid. For example, stainless steel, plastic resin, or the like can be used.

A packing 3 made of an elastic material is disposed at the cap end 4c of the cap 4 that contacts the surface of the discharge head 1. The packing 3 prevents the gas from flowing inside and outside the cap 4 during normal operation to prevent evaporation of the solvent, and prevents the liquid from leaking outside the cap 4 during nozzle cleaning. The material of the packing 3 may be any material as long as it can exhibit the above functions, but has elasticity such as rubber, urethane, etc. and has resistance to the liquid filling the cap. Is preferred. Also, instead of providing the cap 4 with the packing 3,
The cap peripheral portion 4b may be made from an elastic material.

The ultrasonic transducer 5 is disposed on the outer surface of the cap 4. Preferably, the ultrasonic transducer 5 is disposed on the cap bottom 4 a of the cap 4. According to this arrangement, the oscillated ultrasonic wave can be propagated linearly into the discharge nozzle 2 hole. The ultrasonic vibrator 5 may be any one as long as it can be used in an ultrasonic cleaning device or the like, but is preferably a flat plate to be attached to the cap 4. The number and size of the ultrasonic transducers 5 attached to one cap are appropriately determined according to conditions such as the size of the ejection head, the arrangement and number of ejection nozzles, and the like. In addition, it is preferable that the ultrasonic vibration be controlled so that the ultrasonic wave can be controlled according to the type of liquid to be filled in the cap, the depth of the cap, the type of solidified material (attachment), the position of the solidified material, and the like. An ultrasonic vibrator control device (not shown) for controlling the oscillation frequency, intensity, time, etc. of the child is provided.

The droplet discharge device of the present invention is preferably provided with a cap liquid supply device that supplies liquid to the cap recess 4d of the cap 4 and / or a suction device that sucks the liquid in the cap recess 4d and the discharge nozzle 2. To do. FIG. 2 shows a schematic diagram in which the cap liquid supply device 7 and the suction device 8 are connected to the cap 4 via the connecting pipes 9 and 10, respectively. The cap liquid supply device 7 shown in FIG. 2 is configured to supply liquid from the bottom of the cap by the pressure of the water level difference. The connection pipe 9 is a pipe that guides the liquid from the cap liquid supply device 7 to the cap 4. In this embodiment, the connection pipe 9 has flexibility. As other forms, liquid supply from the opening of the cap, liquid supply means such as a pump may be used, or a discharge nozzle liquid supply tank for supplying liquid to the discharge nozzle 2 may be used. Good. The suction device 8
It has a suction pump and collects liquid through the connecting pipe 10. The suction device 8 is preferably one that can apply a sufficient negative pressure in the cap and the discharge nozzle.

The cap 4 preferably includes a heating device (not shown) for heating the liquid 6 in the cap recess 4d in order to enhance the cleaning effect. The location of the heating device is the ultrasonic vibrator 5
It can be set as appropriate as long as it does not affect the process. Instead of providing a heating device, the cap liquid supply device 7 may be provided with a heating device to supply the appropriately heated liquid 6 to the cap recess 4d.

Next, a method for cleaning the droplet discharge device will be described. In the cleaning method of the present invention, first, the cap recess 4d of the cap 4 is filled with the liquid 6, and the cap 4 is covered with the discharge nozzle. The filling method for filling the cap 4 with the liquid 6 includes a method of supplying from the bottom 4a or the peripheral portion 4b of the cap 4 using the cap liquid supply device 7 as described above, a method of supplying from the opening of the cap 4, Discharge nozzle liquid supply tank (for example,
Various methods such as a method of supplying from the discharge liquid supply tank) through the discharge nozzle 2 can be selected. The liquid 6 filling the cap 4 needs to be filled up to at least the uppermost portion of the end 4c (or packing 3) of the cap 4. Preferably, the liquid 6 is piled up using surface tension. This is because, when the cap 4 is attached to the ejection head 1, the presence of gas (bubbles) in the liquid halves the cavitation effect due to ultrasonic waves. This is to prevent generation. At this time, since the liquid 6 is easily spilled from the cap 4, the cap 4 is preferably attached to the ejection head 1 by lowering the ejection head 1. As another filling method, after the empty cap 4 is attached to the discharge head 1, the liquid 6 is filled into the cap 4 from the cap liquid supply device or from the discharge nozzle liquid supply tank through the discharge nozzle 2. You can also. In this case, the peripheral edge 4b or the end 4c of the cap 4 or the packing 3
It is necessary to provide means for venting air such as a valve for letting the air in the cap 4 escape. Liquid 6 is
Although heating can be performed as necessary, in that case, the heating temperature is set lower than the boiling point of the liquid 6.

When the cap 4 filled with the liquid 6 is mounted on the discharge head 1 or when the liquid 6 is supplied to the cap 4 mounted on the discharge head 1, it is preferable that the discharge nozzle 2 is also filled with the liquid 6. FIG. 3 is a schematic cross-sectional view of the discharge nozzle portion for explaining the state in the discharge nozzle hole in a state where the inside of the cap covering the discharge nozzle is filled with liquid, and FIG. FIG. 2 is a diagram showing a discharge nozzle 2 connected to the discharge nozzle and a discharge nozzle liquid supply tank 11 for supplying a liquid to the discharge nozzle 2. Here, the discharge nozzle liquid supply tank 11 may be a discharge nozzle liquid supply tank that supplies a discharge liquid (for example, ink) to the discharge nozzle 2 when the droplet discharge apparatus is operated, or supplies a liquid dedicated for cleaning. It may be a cleaning liquid supply tank. When the operation of the droplet discharge device is stopped, that is, when the liquid in the discharge nozzle is not pressurized, the discharge nozzle 2
The liquid level of the nozzle liquid supply tank 11 communicating with the liquid surface and the liquid surface (interface) in the discharge nozzle 2
The height of the meniscus (hereinafter referred to as a meniscus) is relatively adjusted, and the height (position) of the meniscus in the discharge nozzle 2 hole is kept constant. At this time, the meniscus is in a state in which a hemispherical depression is formed in the discharge nozzle 2 hole as shown in FIG. In this state,
When the cap 4 filled with the liquid 6, for example, a solvent is pressed, the gas between the meniscus and the nozzle port is confined in the discharge nozzle hole as shown in FIG. 3B, or FIG. As a result, bubbles are formed and float inside the discharge nozzle. In the case of FIG. 3B, since the inside of the discharge nozzle hole is not filled with the liquid 6, the ultrasonic wave is not propagated to the nozzle hole, and the solidified substance adhering to the discharge nozzle hole cannot be removed. On the other hand, in the case of FIG. 3C, since bubbles are present in the liquid, the ultrasonic waves are reflected by the bubbles, so that cavitation hardly occurs, and the cleaning effect is reduced by half. Therefore, before mounting the cap 4 filled with liquid, it is necessary to fill the inside of the discharge nozzle 2 with the liquid 6 and exclude the gas existing between the meniscus and the nozzle opening. Therefore, as shown in FIG. 4, the liquid level of the discharge nozzle liquid supply tank 11 is increased, the position of the meniscus of the discharge nozzle 2 is decreased, or both operations are performed. The inside of the discharge nozzle 2 is pressurized through the connecting pipe 12 and the meniscus (liquid surface) is pushed down to at least the discharge nozzle port as shown in FIG. If the cap 4 filled with the liquid 6 is attached in the state of FIG.
The generation of bubbles can be prevented as shown in FIG.

As the liquid 6 filling the cap recess 4 d of the cap 4 and the liquid 6 in the discharge nozzle 2, suitable ones can be appropriately used according to the deposit (solidified material) of the discharge nozzle 2. For example, the liquid 6 may be a discharge liquid itself (for example, ink) that is a source of the solidified product, a main solvent of the discharge liquid, a solvent that is suitable for dissolving the solidified product, a medicine that is adjusted for ultrasonic cleaning, or the like. it can. Here, the liquid 6 in the discharge nozzle 2 and the liquid 6 supplied to the cap recess 4d may be the same or different. The liquid in the discharge nozzle liquid supply tank is normally a discharge liquid (for example, ink). During cleaning, if the liquid in the liquid supply tank is replaced with another liquid (for example, a solvent), or if the discharge nozzle 2 is connected to a tank having another liquid, the inside of the discharge nozzle is replaced with the discharge liquid after cleaning. Work is required. Therefore, for example, the liquid 6 in the discharge nozzle 2 is a discharge liquid, but the liquid 6 filling the cap 4 is used.
Can be cleaned by using different liquids in the discharge nozzle 2 and the cap 4, such as using a main solvent of the discharge liquid. In this way, not only the replacement work with the discharge liquid after cleaning can be omitted, but also the use of a solvent can facilitate the dissolution of the solidified product, and the consumption of the discharge liquid more expensive than the solvent can be minimized. be able to.

Next, after the cap 4 is attached to the ejection head 1 and the cap 4 is filled with the liquid 6, ultrasonic waves (20 kHz or more) are oscillated from the ultrasonic transducer 5 to the ejection nozzle 2,
Clean nozzle holes and nozzle plate. The frequency and intensity of the ultrasonic wave and the irradiation time are appropriately set according to the type of the liquid 6, the type, amount, solubility, and attachment location of the deposit. It is also possible to eliminate uneven cleaning by changing the frequency over time.

In the present invention, the cleaning effect can be further enhanced by vibrating the piezoelectric element 13 for discharging droplets from the discharge nozzle 2 in addition to the ultrasonic vibrator 5.
FIG. 5 is a schematic cross-sectional view of the portion of the discharge nozzle 2 when ultrasonic waves are oscillated from the ultrasonic transducer 5 and the piezoelectric element 13. The piezoelectric element 13 propagates vibration to the liquid 6 via the vibration plate 14.
When ultrasonic waves are generated from the piezoelectric element 13, the ultrasonic waves from the piezoelectric element 13 and the cap 4
If the frequency of each ultrasonic wave is adjusted so that the ultrasonic wave from the ultrasonic transducer 5 disposed in the nozzle resonates, a larger cleaning effect can be obtained with a small amount of energy. Furthermore, cleaning unevenness can be eliminated by changing the resonance frequency over time. In addition, the ultrasonic wave from the ultrasonic transducer 5 is supplemented with the ultrasonic wave from the piezoelectric element 13 where the cleaning power is weak.
The frequency of the ultrasonic wave from the piezoelectric element 13 can also be set. Furthermore, it is possible to perform cleaning only with ultrasonic waves from the piezoelectric element 13.

When the ultrasonic oscillation is finished, the liquid 6 contaminated by the cleaning is discharged from the discharge nozzle 2 and the cap 4. The liquid 6 is preferably discharged by suction from the bottom of the cap 4 while the cap 4 is attached to the ejection head 1. After discharge, a new liquid may be supplied from the discharge nozzle liquid supply tank to wash out the discharge nozzle 2. Thereafter, the liquid or discharge liquid adhering to the nozzle plate surface is removed by wiping or the like. In addition, an absorber can be disposed in the cap 4, and the cap 4 can be covered again to remove the liquid or discharge liquid adhering to the nozzle plate. After the cleaning is completed, the cap 4 is reattached to the ejection head 1 and used as a means for preventing solvent evaporation of the ejection liquid.

The present invention is not limited to the above embodiment, and it goes without saying that the present invention includes various modifications and variations within the scope of the present invention.

In the embodiment of the droplet discharge device of the present invention, it is a schematic cross-sectional view of a discharge head covering a cap. In the droplet discharge device of the present invention, it is a schematic view showing an embodiment provided with a cap liquid supply device and a suction device. In the embodiment of the droplet discharge device of the present invention, it is a schematic cross-sectional view for explaining the state in the discharge nozzle hole in a state where the cap covered with the discharge nozzle is filled with liquid. It is a cross-sectional schematic diagram for demonstrating the method to fill the inside of a discharge nozzle hole with the liquid in the washing | cleaning method of this invention. It is a cross-sectional schematic diagram of the discharge nozzle part which shows one Embodiment of the washing | cleaning method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge head 2 Discharge nozzle 3 Packing 4 Cap 4a Cap bottom part 4b Cap peripheral part 4c Cap end part 4d Cap recessed part 5 Ultrasonic vibrator 6 Liquid 7 Cap liquid supply apparatus 8 Suction apparatus 9 Connection pipe 10 Connection pipe 11 Discharge nozzle liquid supply Tank 12 Connecting pipe 13 Piezoelectric element 14 Diaphragm

Claims (15)

A discharge nozzle for discharging liquid droplets, and a cap covering the discharge port of the discharge nozzle,
The droplet discharge device, wherein the cap includes an ultrasonic transducer. A discharge head comprising a plurality of the discharge nozzles;
The droplet discharge device according to claim 1, wherein the cap has a size capable of covering a plurality of nozzle openings of the discharge nozzle, and a portion in contact with the discharge head has flexibility. . The droplet discharge device according to claim 1, further comprising a piezoelectric element capable of oscillating ultrasonic waves as means for discharging droplets from the discharge nozzle. The droplet discharge device according to claim 1, further comprising: a liquid supply device that fills the recess in the cap with a liquid; and a suction device that sucks the liquid from the recess. 5. The liquid droplet ejection apparatus according to claim 1, wherein the liquid is a liquid capable of dissolving the deposit attached to the ejection nozzle. The said cap is provided with the heating apparatus which heats the said liquid.
The droplet discharge device according to claim 5. A cleaning preparation step of preparing the cleaning so that the liquid is filled in the concave portion of the cap covering the discharge port of the discharge nozzle discharging the droplets, and the cap is covered with the discharge nozzle;
An oscillation / cleaning step of cleaning the discharge nozzle by oscillating ultrasonic waves from an ultrasonic vibrator disposed in the cap;
A method for cleaning a droplet discharge device, comprising: 8. The method of cleaning a droplet discharge device according to claim 7, further comprising a step of vibrating the piezoelectric element between the oscillation and cleaning steps. 9. The method for cleaning a droplet discharge device according to claim 8, further comprising the step of resonating the ultrasonic wave oscillated from the ultrasonic transducer and the ultrasonic wave oscillated from the piezoelectric element. The cleaning preparation step includes
A filling step of filling the recess with a liquid;
A covering step of covering the discharge nozzle with the cap after the filling step;
The method for cleaning a droplet discharge device according to claim 7, comprising: The cleaning preparation step includes
A covering step of covering the discharge nozzle with the cap;
After the covering step, a filling step for filling the recess with liquid;
The method for cleaning a droplet discharge device according to claim 7, comprising: The cleaning preparation step includes
By increasing the liquid level position of the liquid supply tank that supplies the liquid to the discharge nozzle with respect to the position of the liquid surface in the discharge nozzle hole, the discharge is performed to at least the discharge port of the discharge nozzle. The method for cleaning a droplet discharge device according to any one of claims 7 to 11, further comprising a step of filling a nozzle hole with the liquid. The cleaning preparation step includes
By lowering the position of the liquid surface in the discharge nozzle hole relative to the liquid surface position of the discharge liquid tank that supplies the liquid to the discharge nozzle, the discharge is performed up to at least the discharge port of the discharge nozzle. The method for cleaning a droplet discharge device according to any one of claims 7 to 11, further comprising a step of filling a nozzle hole with the liquid. After the oscillation and cleaning process,
The method for cleaning a droplet discharge device according to any one of claims 7 to 13, further comprising a step of sucking and removing at least the liquid in the discharge nozzle and the cap. The method for cleaning a droplet discharge device according to any one of claims 7 to 14, wherein a liquid capable of dissolving deposits attached to the discharge nozzle is used as the liquid.

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