JP2010105164A - Liquid jet head, liquid discharge method, maintenance method, and printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jet head which can form liquid droplets of a desired volume. <P>SOLUTION: The liquid jet head 100 includes a nozzle plate 10, a pressure chamber 22 formed above the nozzle plate 10, a diaphragm 30 formed above the pressure chamber 22, and a first piezoelectric element 40 formed above the diaphragm 30. The nozzle plate 10 has a substrate 11 in which a nozzle hole 12 is bored, and a second piezoelectric element 13 formed below the substrate 11 and provided with an opening 14 in communication with the nozzle hole 12 bored. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head, a liquid ejecting method, a maintenance method, and a printer.

  In recent years, inkjet technology has been used in various fields such as industrial printers and industrial printers as well as household printers. Depending on these fields, the ink jet technology needs to eject inks of various compositions. Among them, particularly high-viscosity inks made of a polymer or the like are difficult to cut off the ink liquid columns ejected from the nozzle holes, and it is difficult to form ink droplets having a desired volume.

For example, in Patent Document 1, a heater for changing the temperature of the liquid is provided on the inner wall of the nozzle, and a temperature difference is generated between the constricted portion of the liquid column and the portion located in the vicinity of the inner wall of the nozzle. A method for separating droplets from a liquid column is disclosed.
JP 2007-229960 A

  However, in the method disclosed in Patent Document 1, the ink around the nozzle is dried by the heat of the heater, and the nozzle hole may be clogged. In addition, when discharging at a high frequency, switching of heater ON / OFF cannot follow and discharge stability may decrease. Furthermore, organic ink may ignite due to the heat of the heater, and there is a problem in terms of safety.

  An object of the present invention is to provide a liquid ejecting head capable of forming a droplet having a desired volume. Another object of the present invention is to provide a liquid ejection method using the liquid ejecting head, a maintenance method, and a printer having the liquid ejecting head.

A liquid ejecting head according to the present invention includes:
A nozzle plate;
A pressure chamber formed above the nozzle plate;
A diaphragm formed above the pressure chamber;
A first piezoelectric element formed above the diaphragm;
Including
The nozzle plate is
A substrate provided with nozzle holes;
A second piezoelectric element formed below the substrate and provided with an opening communicating with the nozzle hole;
Have

  The liquid jet head according to the present invention can form droplets having a desired volume.

  In the description of the present invention, the word “upper” is, for example, “forms another specific thing (hereinafter referred to as“ B ”)“ above ”a specific thing (hereinafter referred to as“ A ”)”. Etc. In the description according to the present invention, in the case of this example, the case where B is directly formed on A and the case where B is formed on A via another are included. The word “upward” is used. Similarly, the term “below” includes a case where B is directly formed under A and a case where B is formed under another through A.

In the liquid jet head according to the present invention,
The second piezoelectric element is
A first electrode;
A piezoelectric layer formed above the first electrode;
A second electrode formed above the piezoelectric layer;
Can have.

In the liquid jet head according to the present invention,
The opening diameter of the opening may be greater than or equal to the opening diameter of the nozzle hole.

In the liquid jet head according to the present invention,
The nozzle plate is
Furthermore, an insulating layer formed between the substrate and the second piezoelectric element can be provided.

In the liquid jet head according to the present invention,
A liquid having a viscosity of 10 mPa · s or more can be discharged.

The liquid ejection method according to the present invention includes:
Preparing a liquid jet head according to the present invention;
Pressurizing the liquid in the pressure chamber with the first piezoelectric element;
Discharging the pressurized liquid from the nozzle hole toward the opening;
Generating sound waves from the second piezoelectric element;
Cutting the liquid ejected into the opening by the sound wave;
including.

In the liquid ejection method according to the present invention,
The liquid discharged into the opening has a liquid column shape,
In the cutting step, the liquid in a liquid column shape can be made into a droplet shape.

In the liquid ejection method according to the present invention,
The step of generating the sound wave can generate the sound wave having a different frequency according to the type of the liquid.

In the liquid ejection method according to the present invention,
The frequency of the sound wave generated when the liquid is oil-based ink may be higher than the frequency of the sound wave generated when the liquid is water-based ink.

The maintenance method according to the present invention includes:
Preparing a liquid jet head according to the present invention;
Generating sound waves from the second piezoelectric element;
Cleaning the inner wall of the opening with the sound wave;
including.

The printer according to the present invention is
The liquid ejecting head according to the invention is provided.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

1. Liquid Ejecting Head First, the liquid ejecting head according to the present embodiment will be described. FIG. 1 is a cross-sectional view schematically showing a main part of the liquid jet head 100 according to the present embodiment. FIG. 2 is a plan view schematically showing a main part of the liquid jet head 100 according to the present embodiment. FIG. 3 is an exploded perspective view of the liquid jet head 100 according to the present embodiment, which is shown upside down from a state in which it is normally used. 1 is a cross-sectional view taken along line AA shown in FIG. FIG. 2 is a plan view of the liquid jet head 100 according to the present embodiment as viewed from below.

  As illustrated in FIGS. 1 to 3, the liquid ejecting head 100 includes a nozzle plate 10, a pressure chamber 22, a vibration plate 30, and a first piezoelectric element 40. Further, the liquid ejecting head 100 can include the pressure chamber substrate 20, the supply path 24, the reservoir 26, and the housing 50.

  The nozzle plate 10 includes a substrate 11 provided with nozzle holes 12 and a second piezoelectric element 13 provided with an opening 14. Further, the nozzle plate 10 can have an insulating layer 18.

  The substrate 11 is made of, for example, nickel, silicon, stainless steel, stainless steel, or the like. The thickness of the substrate 11 is, for example, 10 to 100 μm.

  The nozzle hole 12 is formed in the substrate 11. A plurality of nozzle holes 12 can be provided, and the number thereof is not particularly limited. The nozzle holes 12 can eject liquid (ink) in the thickness direction (−Z direction) of the substrate 11. The viscosity of the liquid discharged from the nozzle hole 12 is, for example, 10 mPa · s or more, further 20 mPa · s or more at 25 ° C.

The second piezoelectric element 13 is formed under the substrate 11. The second piezoelectric element includes a first electrode 15, a piezoelectric layer 16 formed on the first electrode 15, and a second electrode 17 formed on the piezoelectric layer 16. The first electrode 15 and the second electrode 17 are made of, for example, platinum or iridium. The thickness of the first electrode 15 and the second electrode 17 is, for example, 50 nm to 500 nm. The first electrode 15 and the second electrode 17 can be connected to an external drive circuit (not shown). The piezoelectric layer 16 is made of, for example, lead zirconate titanate (Pb (Zr, Ti) O ₃ : PZT). The thickness of the piezoelectric layer 16 is, for example, 300 nm to 3000 nm. The second piezoelectric element 13 can generate a sound wave when the piezoelectric layer 16 vibrates by an applied electric signal. Details will be described later.

  The insulating layer 18 is formed between the substrate 11 and the second piezoelectric element 13. The insulating layer 18 is made of, for example, silicon dioxide or silicon nitride. The thickness of the insulating layer 16 is, for example, 50 nm to 500 nm. The insulating layer 18 can insulate the first electrode 15 and the second electrode 17 from the first substrate 11.

  The opening 14 is formed in the second piezoelectric element 13 and the insulating layer 18. The opening 14 communicates with the nozzle hole 12. The size of the opening diameter 14 </ b> L of the opening 14 is equal to or larger than the size of the opening diameter 12 </ b> L of the nozzle hole 12. More specifically, the opening diameter 14 </ b> L of the opening 14 is larger than the opening diameter 12 </ b> L of the nozzle hole 12. That is, as shown in FIG. 2, the outer periphery of the nozzle hole 12 is located inside the outer periphery of the opening 14 when viewed in plan. In the illustrated example, the outer periphery of the opening 14 is circular, but the shape is not particularly limited, and may be, for example, a quadrangle.

  As shown in FIG. 1, the pressure chamber substrate 20 is formed on the nozzle plate 10 (lower in FIG. 3). The pressure chamber substrate 20 is made of, for example, silicon or nickel. The pressure chamber substrate 20 can partition the pressure chamber 22, the supply path 24 and the reservoir 26.

  The pressure chamber 22, the supply path 24, and the reservoir 26 are formed on the nozzle plate 10 (lower in FIG. 3) as shown in FIG. The pressure chamber 22 communicates with the nozzle hole 12. As shown in FIG. 3, the pressure chamber 22 communicates with a reservoir 26 via a supply path 24. The reservoir 26 can supply liquid to the pressure chamber 22 through the supply path 24. A through hole 28 is formed in the reservoir 26, and the liquid is supplied into the reservoir 26 from the outside through the through hole 28.

  As shown in FIG. 1, the diaphragm 30 is formed on the pressure chamber 22 and the pressure chamber substrate 20 (lower in FIG. 3). The diaphragm 50 is made of, for example, an insulating film such as zirconium dioxide or silicon dioxide, a metal film such as nickel, or a polymer material film such as polyimide.

The first piezoelectric element 40 is formed on the diaphragm 30 above the pressure chamber 22. Although not shown, the first piezoelectric element 40 may be formed on the diaphragm 30 via a diaphragm or an adhesive. The first piezoelectric element 40 can vibrate the diaphragm 30 in the vertical direction (Z direction) in accordance with an applied electric signal. The first piezoelectric element 40 has a structure in which a piezoelectric layer is sandwiched between electrodes. The direction in which the electrodes of the first piezoelectric element 40 extend may be perpendicular (longitudinal mode) to the vibration direction of the diaphragm 30 or may be parallel (transverse mode). In the longitudinal mode, the upper part of the first piezoelectric element 40 is fixed to a fixed substrate (not shown). The electrodes of the first piezoelectric element 40 are connected to an external drive circuit by, for example, a cable (not shown). The piezoelectric layer of the first piezoelectric element 40 is made of, for example, lead zirconate titanate (Pb (Zr, Ti) O ₃ : PZT). The electrodes of the first piezoelectric element 40 are made of, for example, platinum or iridium.

  As shown in FIG. 3, the housing 50 can accommodate the first piezoelectric element 40, the nozzle plate 10, and the like. The housing 50 is made of, for example, various resin materials or various metal materials.

  The liquid jet head 100 according to the present embodiment has, for example, the following characteristics.

  The liquid ejecting head 100 can include the second piezoelectric element 13 provided with the opening 14 communicating with the nozzle hole 12. The second piezoelectric element 13 can generate a sound wave when the piezoelectric layer 16 vibrates. A droplet having a desired volume (size) can be formed by the sound wave. Details will be described later.

  In the liquid ejecting head 100, the opening diameter 14 </ b> L of the opening 14 is equal to or larger than the opening diameter 12 </ b> L of the nozzle hole 12. More specifically, the opening diameter 14 </ b> L of the opening 14 is larger than the opening diameter 12 </ b> L of the nozzle hole 12. Therefore, the liquid ejected from the nozzle hole 12 can fly without contacting the second piezoelectric element 13. That is, the second piezoelectric element 13 does not prevent the liquid from flying, and the liquid can fly in a desired direction.

  In the liquid ejecting head 100, the insulating layer 18 can be formed between the substrate 11 and the second piezoelectric element 13. The insulating layer 18 can insulate the first electrode 15 and the second electrode 17 from the first substrate 11. This is particularly effective when the substrate 11 is made of a conductor.

  In the liquid jet head 100, for example, a high-viscosity liquid having a viscosity of 10 mPa · s or more and further 20 mPa · s or more can be discharged at 25 ° C. That is, as described above, since the second piezoelectric element 13 can generate a sound wave, the sound wave can cut even a high-viscosity liquid to form a droplet having a desired volume. be able to.

2. Next, a method for manufacturing a liquid jet head according to the present embodiment will be described with reference to the drawings. 4 to 7 are cross-sectional views schematically showing manufacturing steps of main parts of the liquid jet head 100 according to the present embodiment. 4 and 5 are shown upside down from FIG. 1 for convenience.

  As shown in FIG. 4, the insulating layer 18, the second electrode 17, the piezoelectric layer 16, and the first electrode 15 are formed on the substrate 11 in this order. The insulating layer 18 is formed by, for example, a CVD (Chemical Vapor Deposition) method. The first electrode 15 and the second electrode 17 are formed by, for example, a sputtering method, a plating method, a vacuum evaporation method, or the like. The piezoelectric layer 16 is formed by, for example, a CVD method, a MOD (Metal Organic Deposition) method, a sputtering method, or the like. Each layer can be patterned into a desired shape for each layer formation.

  As shown in FIG. 5, the second piezoelectric element 13 and the insulating layer 18 are patterned to form the opening 14. Next, the substrate 11 is patterned to form nozzle holes 12. Thus, the nozzle plate 10 can be formed. In addition, the formation of the opening part 14 and the formation of the nozzle hole 12 are not limited.

  As shown in FIG. 6, the diaphragm 30 is formed on the pressure chamber substrate 20. The diaphragm 30 is formed by, for example, a CVD method, a sputtering method, or a plating method. Next, the first piezoelectric element 40 is formed on the vibration plate 30. The first piezoelectric element 40 is formed by, for example, a known method.

  As shown in FIG. 7, the pressure chamber substrate 20 is patterned to form an opening 20a. The patterning is performed using a photolithography technique and an etching technique, and the vibration plate 30 can function as an etching stopper.

  As shown in FIG. 1, the nozzle plate 10 is formed under the pressure chamber substrate 22 so that the opening 20 a and the nozzle hole 12 communicate with each other. Thereby, the pressure chamber 22 can be formed. At the same time, the supply path 24 and the reservoir 26 can be formed.

  The liquid ejecting head 100 can be manufactured by the above method. Note that the manufacturing method of the liquid jet head 100 is not limited to the above-described manufacturing method.

3. Liquid Discharge Method Next, the liquid discharge method according to the present embodiment will be described. In the liquid ejection method according to the present embodiment, the liquid jet head according to the present invention is prepared. Hereinafter, an example using the liquid ejecting head 100 will be described. 8 to 11 are diagrams for explaining the liquid ejection method according to the present embodiment.

  As shown in FIG. 8, the first piezoelectric element 40 pressurizes the liquid 60 in the pressure chamber 22 and the nozzle hole 12. More specifically, the diaphragm 30 is vibrated (displaced) by applying an electrical signal to the first piezoelectric element 40, and the volume of the pressure chamber 40 is changed by the displacement of the diaphragm 30 to apply pressure to the liquid 60. .

  As shown in FIG. 9, the pressurized liquid 60 is discharged from the nozzle hole 12 toward the opening 14. As described above, the liquid 60 has a high viscosity at 25 ° C., for example, 10 mPa · s or more, and further 20 mPa · s or more. Therefore, for example, the liquid 60 discharged from the nozzle hole 12 into the opening 14 has a liquid column shape (liquid column 60 a), and is continuous with the liquid 60 in the pressure chamber 22 and the nozzle hole 12.

  As shown in FIG. 10, an electric signal is given to the second piezoelectric element 13, and a sound wave 70 is generated from the second piezoelectric element 13 toward the liquid column 60a. The second piezoelectric element 13 can generate sound waves 70 having different frequencies depending on the type of liquid. Specifically, the frequency of the sound wave 70 can be changed by changing the electrical signal applied to the second piezoelectric element 13.

  When the liquid 60 is water-based ink, the second piezoelectric element 13 can generate a sound wave 70 having a frequency of 20 kHz to 100 kHz, for example. For example, water-based ink tends to cause cavitation due to sound waves having a frequency of 20 kHz to 100 kHz. By this cavitation, as shown in FIG. 11, the liquid 60 (liquid column 60a) discharged into the opening 14 can be cut. The cut liquid 60 becomes droplets 62 and flies in the −Y direction. The water-based ink is ink that uses water as a main solvent.

  When the liquid 60 is oil-based ink, the second piezoelectric element 13 can generate a sound wave 70 having a frequency of 1 MHz or more, for example. Oil-based inks are less likely to cause cavitation than water-based inks, for example. Therefore, a sound wave 70 having a higher frequency than that in the case of water-based ink is generated, and molecules in the oil-based ink are vibrated. By this vibration, the liquid column 60a can be cut as shown in FIG. Oil-based ink is ink that uses an organic solvent as a main solvent.

  The liquid ejection method according to the present embodiment has the following features, for example.

  In the liquid discharge method according to the present embodiment, the liquid 60 discharged into the opening 14 can be cut by the sound wave 70 generated from the second piezoelectric element 13 as described above. That is, the droplets 62 having a desired volume can be formed by the sound wave 70.

  In the liquid discharge method according to the present embodiment, the sound wave 70 having a different frequency can be generated according to the type of the liquid 60, and the liquid 60 discharged into the opening 14 can be cut. More specifically, the frequency of the sound wave 70 generated when the liquid 60 is oil-based ink is higher than the frequency of the sound wave 70 generated when the liquid 60 is water-based ink. Thereby, the liquid ejection method according to the present embodiment can deal with various types of liquid 60.

4). Maintenance Method Next, a maintenance method according to the present embodiment will be described. In the maintenance method according to the present embodiment, the liquid jet head according to the present invention is prepared. Hereinafter, an example using the liquid ejecting head 100 will be described. FIG. 12 is a diagram for explaining a maintenance method according to the present embodiment.

  As shown in FIG. 12, when the liquid ejecting head 100 is on standby (for example, when an electric signal is not given to the first piezoelectric element 40), an electric signal is given to the second piezoelectric element 13, and the second piezoelectric element 13 is given. A sound wave 70 is generated from the head toward the inner wall 14 a of the opening 14. The inner wall 14 a of the opening 14 can also be said to be a side surface of the second piezoelectric element 13 that partitions the opening 14. For example, a substance constituting the liquid 60 may adhere to the inner wall 14a. In such a case, the sound wave 70 can be generated to remove the deposit on the inner wall 14a. That is, the inner wall 14a of the opening 14 can be cleaned. The frequency of the sound wave 70 generated at this time can be, for example, 20 kHz to 100 kHz. Since the sound wave 70 having such a frequency has low directivity, a wide area can be cleaned.

  In the maintenance method according to the present embodiment, as described above, the inner wall 14a of the opening 14 can be easily cleaned without preparing a separate cleaning device.

5). Printer Next, the printer according to the present embodiment will be described. The printer according to this embodiment includes the liquid ejecting head according to the present invention. Here, a case where the printer 300 according to the present embodiment is an inkjet printer will be described. FIG. 13 is a perspective view schematically showing the printer 300 according to the present embodiment.

  The printer 300 includes a head unit 330, a drive unit 310, and a control unit 360. In addition, the printer 300 includes an apparatus main body 320, a paper feeding unit 350, a tray 321 on which the recording paper P is placed, a discharge port 322 for discharging the recording paper P, and an operation panel 370 disposed on the upper surface of the apparatus main body 320. And can be included.

  The head unit 330 includes, for example, an ink jet recording head (hereinafter also simply referred to as “head”) configured from the liquid ejecting head 100 described above. The head unit 330 further includes an ink cartridge 331 that supplies ink to the head, and a transport unit (carriage) 332 on which the head and the ink cartridge 331 are mounted.

  The drive unit 310 can reciprocate the head unit 330. The drive unit 310 includes a carriage motor 341 serving as a drive source for the head unit 330, and a reciprocating mechanism 342 that receives the rotation of the carriage motor 341 and reciprocates the head unit 330.

  The reciprocating mechanism 342 includes a carriage guide shaft 344 supported at both ends by a frame (not shown), and a timing belt 343 extending in parallel with the carriage guide shaft 344. The carriage guide shaft 344 supports the carriage 332 while allowing the carriage 332 to freely reciprocate. Further, the carriage 332 is fixed to a part of the timing belt 343. When the timing belt 343 is caused to travel by the operation of the carriage motor 341, the head unit 330 is reciprocated by being guided by the carriage guide shaft 344. During this reciprocation, ink is appropriately discharged from the head, and printing on the recording paper P is performed.

  The control unit 360 can control the head unit 330, the driving unit 310, and the paper feeding unit 350.

  The paper feed unit 350 can feed the recording paper P from the tray 321 to the head unit 330 side. The paper feed unit 350 includes a paper feed motor 351 serving as a drive source thereof, and a paper feed roller 352 that is rotated by the operation of the paper feed motor 351. The paper feed roller 352 includes a driven roller 352a and a drive roller 352b that face each other up and down across the feeding path of the recording paper P. The drive roller 352b is connected to the paper feed motor 351. When the paper feeding unit 350 is driven by the control unit 360, the recording paper P is sent so as to pass below the head unit 330.

  The head unit 330, the drive unit 310, the control unit 360, and the paper feed unit 350 are provided inside the apparatus main body 320.

  The printer 300 can include the liquid ejecting head according to the invention. As described above, the liquid jet head according to the present invention can form droplets having a desired volume. Therefore, the printer 300 that can form droplets having a desired volume can be obtained.

  In the example described above, the case where the printer 300 is an ink jet printer has been described. However, the printer of the present invention can also be used as an industrial liquid ejecting apparatus. As the liquid (liquid material) discharged in this case, various functional materials adjusted to an appropriate viscosity with a solvent or a dispersion medium can be used.

  Although the embodiments of the present invention have been described in detail as described above, those skilled in the art will readily understand that many modifications are possible without substantially departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention.

FIG. 3 is a cross-sectional view schematically illustrating the liquid ejecting head according to the embodiment. FIG. 3 is a plan view schematically showing the liquid ejecting head according to the embodiment. FIG. 3 is an exploded perspective view schematically illustrating the liquid ejecting head according to the embodiment. FIG. 6 is a cross-sectional view schematically showing a manufacturing process of the liquid jet head according to the embodiment. FIG. 6 is a cross-sectional view schematically showing a manufacturing process of the liquid jet head according to the embodiment. FIG. 6 is a cross-sectional view schematically showing a manufacturing process of the liquid jet head according to the embodiment. FIG. 6 is a cross-sectional view schematically showing a manufacturing process of the liquid jet head according to the embodiment. The figure for demonstrating the liquid discharge method which concerns on this embodiment. The figure for demonstrating the liquid discharge method which concerns on this embodiment. The figure for demonstrating the liquid discharge method which concerns on this embodiment. The figure for demonstrating the liquid discharge method which concerns on this embodiment. The figure for demonstrating the maintenance method which concerns on this embodiment. 1 is a perspective view schematically showing a printer according to an embodiment.

Explanation of symbols

10 nozzle plate, 11 substrate, 12 nozzle hole, 13 second piezoelectric element,
14 opening, 15 first electrode, 16 piezoelectric layer, 17 second electrode, 18 insulating layer,
20 pressure chamber substrate, 22 pressure chamber, 24 supply path, 26 reservoir, 28 through-hole,
30 diaphragm, 40 first piezoelectric element, 50 housing, 60 liquid, 62 droplet,
70 sound wave, 100 liquid jet head, 300 printer, 310 drive unit,
320 device main body, 321 tray, 322 discharge port, 330 head unit,
331 ink cartridge, 332 carriage, 341 carriage motor,
342 reciprocating mechanism, 343 timing belt, 344 carriage guide shaft,
350 paper feed unit, 351 paper feed motor, 352 paper feed roller, 360 control unit,
370 Operation panel

Claims (11)

A nozzle plate;
A pressure chamber formed above the nozzle plate;
A diaphragm formed above the pressure chamber;
A first piezoelectric element formed above the diaphragm;
Including
The nozzle plate is
A substrate provided with nozzle holes;
A second piezoelectric element formed below the substrate and provided with an opening communicating with the nozzle hole;
A liquid ejecting head. In claim 1,
The second piezoelectric element is
A first electrode;
A piezoelectric layer formed above the first electrode;
A second electrode formed above the piezoelectric layer;
A liquid ejecting head. In claim 1 or 2,
The liquid ejecting head, wherein an opening diameter of the opening is equal to or larger than an opening diameter of the nozzle hole. In any of claims 1 to 3,
The nozzle plate is
The liquid ejecting head further includes an insulating layer formed between the substrate and the second piezoelectric element. In any of claims 1 to 4,
A liquid ejecting head that ejects a liquid having a viscosity of 10 mPa · s or more. Preparing the liquid jet head according to claim 1;
Pressurizing the liquid in the pressure chamber with the first piezoelectric element;
Discharging the pressurized liquid from the nozzle hole toward the opening;
Generating sound waves from the second piezoelectric element;
Cutting the liquid ejected into the opening by the sound wave;
A liquid ejection method comprising: In claim 6,
The liquid discharged into the opening has a liquid column shape,
The step of cutting is a liquid ejection method in which the liquid in a liquid column shape is made into a droplet shape. In claim 6 or 7,
The step of generating a sound wave is a liquid ejection method of generating the sound wave having a different frequency according to the type of the liquid. In claim 8,
The liquid ejection method, wherein a frequency of the sound wave generated when the liquid is oil-based ink is higher than a frequency of the sound wave generated when the liquid is water-based ink. Preparing the liquid jet head according to claim 1;
Generating sound waves from the second piezoelectric element;
Cleaning the inner wall of the opening with the sound wave;
Including maintenance methods.   A printer comprising the liquid ejecting head according to claim 1.

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