JP7268396B2 - Liquid ejection head, droplet forming device, droplet forming method, and dispensing device - Google Patents

Description

The present invention relates to a liquid ejection head, a droplet forming apparatus, a droplet forming method, and a dispensing apparatus.

In recent years, along with the progress of stem cell technology, technology development has been carried out to form tissue bodies by ejecting cell suspensions. In this technical field, a liquid ejecting apparatus employing an ink-jet method has been developed, which is capable of ejecting a cell suspension without damaging the cells.

For example, a film member having a discharge port formed in the center thereof is deformed by a piezoelectric element arranged in a ring shape on the periphery of the lower surface of the film member, and the hydraulic pressure of the liquid contained in the upper surface of the film member is changed. A droplet ejection device that ejects liquid from an ejection port using such a liquid droplet has been proposed (see, for example, Patent Document 1).

An object of the present invention is to provide a liquid ejection head capable of stable ejection.

A liquid ejection head of the present invention as a means for solving the above-mentioned problems includes an ejection port, a liquid holding portion for holding the liquid to be ejected from the ejection port, and a liquid holding portion connected to the liquid holding portion so as to allow the liquid to flow. a pair of liquid storage units that store the liquid; and a pair of liquid feeding units that are connected to the pair of liquid storage units and feed the liquid between the liquid storage unit and the liquid storage unit. and a pair of switching portions respectively arranged between the liquid feeding portion and the liquid storing portion for switching the liquid storing portion to which the liquid is fed.

According to the present invention, it is possible to provide a liquid ejection head capable of stable ejection.

FIG. 1A is a schematic diagram showing an example of a liquid ejection head. FIG. 1B is a schematic diagram showing an example of the operation of the liquid ejection head. FIG. 2 is a schematic diagram showing an example of liquid level detection means for detecting the liquid level height of the solution in the liquid holding portion of the liquid ejection head. FIG. 3A is an explanatory diagram showing an example of a stirring operation of the liquid in the liquid holding section using a pair of liquid feeding sections. FIG. 3B is an explanatory diagram showing an example of a stirring operation of the liquid in the liquid holding section using a pair of liquid feeding sections. FIG. 3C is an explanatory diagram showing an example of a stirring operation of the liquid in the liquid holding section using a pair of liquid feeding sections. FIG. 4A is an explanatory diagram showing an example of alternate operation of a pair of liquid sending units. FIG. 4B is an explanatory diagram showing an example of alternate operation of a pair of liquid feeding units. FIG. 4C is an explanatory diagram showing an example of alternate operation of a pair of liquid feeding units. FIG. 5 is an explanatory diagram showing an example of transition of the liquid level height of the liquid holding section when the pair of liquid feeding sections alternately operate. FIG. 6 is a plan view showing an example of the liquid ejection device of the present invention. FIG. 7A is a schematic diagram showing an example of the operation of the switching section in the liquid ejection head of the present invention. FIG. 7B is a schematic diagram showing an example of the operation of the switching section in the liquid ejection head of the present invention. FIG. 7C is a schematic diagram showing an example of the operation of the switching section in the liquid ejection head of the present invention.

(liquid ejection head)
The liquid ejection head of the present invention includes an ejection port, a liquid holding portion for holding the liquid to be ejected from the ejection port, and a pair of liquids which are connected to the liquid holding portion so as to allow the liquid to flow therethrough and store the liquid. a storage portion, a pair of liquid feeding portions connected to the pair of liquid storage portions and feeding the liquid between the liquid storage portion and the liquid storage portion, the liquid feeding portion and the liquid storage portion and a pair of switching portions for switching the liquid storage portion that feeds the liquid, and if necessary, other members.

The present inventors have studied a liquid ejection head capable of stable ejection, and have obtained the following findings.
In a conventional liquid ejection device, when a cell suspension is ejected as the liquid, the liquid amount decreases as the cell suspension is ejected, and the liquid pressure applied to the ejection port decreases, resulting in a small ejection amount. There is a problem of becoming

Specifically, in the conventional liquid ejection device, the upper side of the liquid storage container is open to the atmosphere in order to remove air bubbles generated inside the liquid storage container. (Static pressure) depends on the height from the membrane member to the liquid surface of the cell suspension, that is, the so-called head. Therefore, the driving force for ejecting droplets is determined by the combination of the dynamic pressure due to the contraction stress (vibration) of the piezoelectric element that drives the film member and the static pressure due to the water head. For this reason, in the conventional liquid ejecting apparatus, the liquid volume of the cell suspension in the liquid container decreases due to the continuous ejection of droplets, and when the water head decreases, the driving force for ejecting the droplets decreases. As a result, there is a problem that "non-ejection" in which droplets cannot be ejected may occur.
In addition, in the conventional liquid ejecting device, when the cell suspension is allowed to stand still, the ejecting port is likely to be clogged with precipitated cells, which may cause "non-ejection".

Accordingly, the present inventors proposed an ejection port, a liquid holding portion for holding the liquid to be ejected from the ejection port, a pair of liquid storage portions respectively connected to the liquid holding portions so that the liquid can be circulated and storing the liquid, a pair of liquid feeding sections connected to the pair of liquid storage sections and feeding liquid between the liquid storage section and the liquid holding section; By providing a liquid discharge head having a pair of switching parts for switching the liquid storage part to be sent, it is possible to selectively and reliably send the liquid into the liquid holding part where the amount of liquid is reduced. Therefore, the inventors have found that the liquid level in the liquid holding portion can be easily kept constant, and the discharge can be stabilized.

It should be noted that the present invention is not limited to the case of a cell suspension, and can be used in the case of a white ink containing a heavy pigment contained in the ink or an ink containing fine metal flakes to express a metallic effect on a printed matter. may be used to agitate the ink in the liquid holding portion so that the ink does not settle.

For convenience of explanation, the liquid holding portion side of the vibrating member is the upper side, the nozzle plate side of the vibrating member is the lower side, and the upper side is the upper side, and the lower side is the lower side.

<Liquid holding part>
The liquid retaining portion is a member that retains liquid.
The liquid holding portion preferably has a nozzle plate having an ejection port, further has a vibrating member, and more preferably has other members as necessary.
When the droplet discharge means is an open head, it is preferable to have an atmosphere opening portion on the upper side. In addition, the position of the atmosphere opening portion is not limited to the upper portion. Air bubbles entrained in the liquid are configured to be discharged from the air release portion.

The shape, size, material, and structure of the liquid holding portion are not particularly limited, and can be appropriately selected according to the purpose.
Examples of materials for the liquid holding portion include stainless steel, nickel, aluminum, silicon dioxide, alumina, zirconia, and the like.
Among these, when particles are contained in a liquid and cells or proteins are used as the particles, it is preferable to use materials with low adhesion to cells or proteins.
Adhesion of cells is generally said to depend on the contact angle of the material with water, and the adhesion of cells is low when the material is highly hydrophilic or highly hydrophobic. Various metal materials and ceramics (metal oxides) can be used as highly hydrophilic materials, and fluorine resins and the like can be used as highly hydrophobic materials.
In addition to these, it is also conceivable to reduce the cell adhesiveness by coating the surface of the material. For example, the surface of the material can be coated with the aforementioned metal or metal oxide material, or with a synthetic phospholipid polymer that mimics cell membranes (for example, Lipidure manufactured by NOF Corporation).
The volume of the liquid holding part is not particularly limited and can be appropriately selected according to the purpose. In particular, when an expensive liquid such as a cell suspension is used as the liquid, the volume of the liquid holding part is preferably 1 μL or more and 200 μL or less so that droplets can be formed in a small amount. .

The liquid retained by the liquid retaining portion is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include water, organic solvents, cell suspensions, and the like. Organic solvents include, for example, alcohols, mineral oils, vegetable oils and the like.
When water is used as the liquid, it preferably contains additives such as a wetting agent for suppressing evaporation and a surfactant for lowering surface tension. As additives contained in the liquid, very general materials used for inkjet inks can be used.
Particles contained in the liquid retained by the liquid retaining portion are not particularly limited and can be appropriately selected according to the purpose. Examples thereof include metal microparticles, inorganic microparticles, and cells.
Materials for the fine metal particles are not particularly limited, and examples thereof include silver and copper. When the material of the fine metal particles is silver or copper, they can be used for drawing wiring with discharged droplets.
Materials for the inorganic fine particles are not particularly limited, and examples thereof include titanium oxide and silicon oxide. When the material of the inorganic fine particles is titanium oxide or silicon oxide, it can be used for white ink applications, spacer material application applications, and the like.
Cells are not particularly limited, and examples include animal cells, plant cells, bacteria and the like. The cells are preferably animal cells, particularly human-derived cells. When the cells are human-derived cells, they can be used for cell ejection devices for forming cell plates for drug testing and tissue pieces for evaluation of cosmetics.

－Nozzle plate－
The nozzle plate is a member that is formed with ejection openings (nozzles) and that ejects the liquid held in the liquid holding portion as droplets from the ejection openings by vibration caused by the amplitude motion of the liquid.
The nozzle plate is fixed to the lower end portion of the liquid holding portion when the droplet ejection means is an open head.
The nozzle plate is fixed to the upper end portion of the liquid holding portion when the liquid ejection head is a closed head.
The liquid held in the liquid holding portion is ejected as droplets from ejection openings, which are through holes, due to vibration of the nozzle plate.

The planar shape, size, material, and structure of the nozzle plate are not particularly limited, and can be appropriately selected according to the purpose.
Examples of the planar shape of the nozzle plate include circular, elliptical, rectangular, square, and rhombic.
The material of the nozzle plate is not particularly limited and can be appropriately selected according to the purpose. It is preferable to use a material having a certain degree of hardness, and examples thereof include metals, ceramics, polymer materials, etc. Specific examples include stainless steel, nickel, aluminum, silicon dioxide, alumina, zirconia, and the like. Among these materials, when cells or proteins are used as the particles, it is preferable to use materials with low adhesion to cells or proteins, as in the case of the liquid holding portion. Adhesion of cells is generally considered to depend on the contact angle of the material with water, and when the material is highly hydrophilic or hydrophobic, the adhesion of cells is low. Examples of highly hydrophilic materials include metals and ceramics (metal oxides). Examples of highly hydrophobic materials include fluororesins. In addition, cell adhesiveness can be reduced by coating the surface of the material. The method of coating the material surface is not particularly limited and can be appropriately selected according to the purpose. Coating with a synthetic phospholipid polymer (for example, manufactured by NOF Corporation, trade name: Lipidure) can be mentioned.

-Outlet-
There are no particular restrictions on the number of ejection ports, the arrangement mode, the spacing (pitch), the shape of the openings, the size of the openings, and the like, and they can be appropriately selected according to the purpose.
The number of ejection openings arranged is not particularly limited, and can be appropriately selected according to the purpose. , more preferably 1 to 4 rows. By providing one or more rows of ejection openings, the number of droplets ejected per unit time can be increased, and the rows can be changed according to the type of particles (for example, the type of cell) to eject at one time. can be done.
The number of ejection openings per row is not particularly limited and may be appropriately selected depending on the intended purpose. More preferred are: When the number of ejection openings per row is 2 or more and 100 or less, the number of droplets ejected per unit time can be increased, so that a droplet forming apparatus with high productivity can be provided. can.
The arrangement mode of the ejection openings is not particularly limited, and can be appropriately selected according to the purpose.
When there are multiple rows of ejection ports, it is preferable to provide a partition member between each row in order to prevent interference between droplets ejected from adjacent ejection ports and to improve particle detection sensitivity. . Examples of the partition member include a partition plate.
The ejection ports are preferably arranged at regular intervals, and the interval (pitch) P, which is the shortest distance between the centers of adjacent ejection ports, is not particularly limited and may be appropriately selected according to the purpose. However, for example, 50 μm or more and 1,000 μm or less is preferable.
The opening shape of the ejection port is not particularly limited and can be appropriately selected according to the purpose.
The average diameter of the ejection port is not particularly limited and can be appropriately selected depending on the intended purpose.
When the particles are, for example, animal cells, particularly human cells, the size of human cells is generally 5 μm or more and 50 μm or less. 10 μm or more and 100 μm or less is preferable.
On the other hand, if the droplets are too large, it will be difficult to achieve the purpose of forming fine droplets. Therefore, the average diameter of the ejection port is more preferably 10 μm or more and 200 μm or less.

-Vibration member-
The vibrating member is a member that vibrates the nozzle plate to eject liquid droplets from ejection ports (nozzles). The vibrating member may also be referred to as a displacement section.
The vibrating member is formed on the lower surface side of the nozzle plate when the droplet ejecting means is an open head.
The vibrating member is formed on the upper surface side of the nozzle plate when the liquid droplet ejecting means is a closed head.
The shape, size, material, and structure of the vibrating member are not particularly limited, and can be appropriately selected according to the purpose.
The shape of the vibrating member is not particularly limited, and can be appropriately designed according to the shape of the nozzle plate. is preferably provided. In the case of an open head, it is preferable to form a vibrating member having a circular planar shape (ring shape) around the ejection port.

The vibrating member is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include a piezoelectric element and a material having a coefficient of linear expansion different from that of the nozzle plate.

The piezoelectric element includes, for example, a structure in which electrodes for applying a voltage are provided on the upper and lower surfaces of a piezoelectric material. In this case, by applying a voltage between the upper and lower electrodes of the piezoelectric element from the driving means, a compressive stress is applied in the horizontal direction of the film, and the nozzle plate can be vibrated in the vertical direction of the film.
The piezoelectric material is not particularly limited and can be appropriately selected according to the purpose. Examples include lead zirconate titanate (PZT), bismuth iron oxide, metal niobate, barium titanate, or these materials to which metals or different oxides are added. Among these, lead zirconate titanate (PZT) is preferred.

The material having a coefficient of linear expansion different from that of the nozzle plate is a material that vibrates the nozzle plate using the difference in coefficient of linear expansion by applying the material on the nozzle plate and heating the material.
Means for heating a material having a coefficient of linear expansion different from that of the nozzle plate is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include heaters.

The vibrating member is driven by the driving section. The drive section applies an ejection waveform (ejection signal) to the vibrating member to vibrate the nozzle plate to form droplets. In other words, the drive section applies a discharge waveform to the vibrating member and controls the vibration state of the nozzle plate, thereby discharging the solution held in the liquid holding section as droplets from the discharge port.

<Pair of Liquid Reservoir>
The pair of liquid reservoirs are members that are respectively connected to the liquid holders so that the liquid can flow therethrough, and that store the liquid. That is, the liquid storage part is a member that temporarily stores the liquid.
The shape, material, size, structure, etc. of the liquid reservoir are not particularly limited and can be appropriately selected according to the purpose.
Examples of the shape of the liquid reservoir include a tubular shape and a tubular shape.
Examples of materials for the liquid reservoir include resins, rubbers, elastomers, and metals. Among these, resin is preferable. Examples of resins include silicone rubber, nylon, and urethane.

The liquid reservoir is preferably replaceable. If the liquid reservoir is replaceable, it is possible to change the type of ejection target by replacing only the liquid reservoir.
The volume of the liquid reservoir is preferably variable. If the volume of the liquid reservoir is changeable, it is possible to adjust the amount of suction and discharge required to agitate the ejection target, which varies depending on the type of the ejection target and the volume change of the liquid reservoir. It can be changed by adjusting the inner diameter, length, shape, and the like.
The volume of the liquid reservoir can be calculated, for example, from the inner diameter A and the length B of the liquid reservoir by the following equation, volume=(A/2) ² π×B.
It is preferable that the volumes of the liquid reservoirs be the same, since unnecessary liquid reservoirs are not generated when the liquid suction amount and the discharge amount are made the same in order to keep the liquid level constant.

It is preferable that the liquid reservoir communicates with the liquid holder and is arranged at an angle with respect to the ejection port (or nozzle plate). That is, it is preferable that they are arranged to be inclined with respect to the central axis passing through the discharge port.
The inclination angle of the liquid reservoir is preferably 45° or more and 80° or less with respect to the ejection port (or nozzle plate). By setting the inclination angle of the liquid reservoir to 45° or more and 80° or less, it is possible to generate an upward flow in the liquid reservoir and disperse the particles deposited on the bottom of the liquid reservoir.
It is preferable that the liquid reservoirs are arranged symmetrically with respect to the central axis passing through the ejection port, in order to make the distribution of the particles in the liquid reservoir uniform.
It is preferable that the central axes of the liquid reservoirs do not lie on the same plane, because it is possible to disperse the particles near the inner wall of the liquid reservoir.
It is preferable that the liquid reservoir retains a predetermined amount of liquid in advance. Since the liquid reservoir holds a predetermined amount of liquid in advance, the liquid to be supplied to the liquid holding section can be rapidly supplied.
The "predetermined amount" of the predetermined amount of liquid means an amount equal to or greater than the amount of liquid ejected from the ejection port.

<A pair of liquid sending parts>
The pair of liquid feeding parts are members for sucking and discharging the liquid in the liquid holding part.
The shape, material, size, structure, and the like of the liquid feeding portion are not particularly limited, and can be appropriately selected according to the purpose.
Examples of the liquid feeding unit include pumps capable of sucking, holding, and discharging a fixed amount of liquid, such as syringe type and plunger type electric pumps.

The pair of liquid feeding units can be switched to a plurality of liquid feeding amounts, so that when the type of discharge target or the volume of the liquid holding unit is changed, the amount of suction and discharge required to sufficiently stir the discharge target can be achieved. This is preferable because it can be switched.
It is preferable that the liquid feeding amount of the pair of liquid feeding parts be the same, since the liquid level in the liquid holding part does not change during stirring and the liquid level can be kept constant.
Here, the amount of liquid to be fed includes, for example, the amount of aspirated liquid and the amount of discharged liquid.
In the present invention, each maximum amount of aspirated liquid in the liquid feeding section is less than the volume of the liquid storing section. As a result, it is possible to prevent the liquid being agitated in the liquid holding section from entering the liquid feeding section, so it is not necessary to clean the inside of the liquid feeding section or replace the liquid feeding section each time the type of ejection target is changed. .

Further, it is preferable that one of the pair of liquid-feeding units performs a discharging operation in synchronization with the suction operation of the other liquid-feeding unit. As a result, even when the liquid ejection head performs the ejection operation while maintaining the uniform dispersion state of the particles contained in the solution in the liquid holding portion, the liquid surface height from the ejection port (or nozzle plate) does not change. , Since the static pressure applied to the ejection port (or nozzle plate) is constant, it is possible to eject droplets with a constant falling speed and a constant concentration of contained particles without changing the falling speed of the droplets. becomes.
It is preferable that the pair of liquid feeding units be switchable between a plurality of liquid feeding speeds.
Here, the liquid feeding speed includes, for example, a suction speed, a discharge speed, and the like.

It is preferable that the liquid suction operation of one of the pair of liquid feeding units is performed during the ejection operation of the liquid ejection head. By carrying out the liquid suction operation of one of the pair of liquid feeding units during the ejection operation of the liquid ejection head, it is possible to prevent "lowering of productivity due to stopping ejection" and "drying of the ejection port". can.

<A pair of switching parts>
The pair of switching parts are members that are arranged between the liquid feeding part and the liquid storage part, respectively, and switch the liquid storage part that feeds the liquid.
The shape, size, material, and structure of the switching portion are not particularly limited, and can be appropriately selected according to the purpose.
The switching unit is not particularly limited and can be appropriately selected according to the purpose. Among these, multi-way valves are preferred. If the switching section is a multi-way valve, it is possible to control liquid feeding to a plurality of liquid storage sections simply by providing one switching section for each branch point between the liquid feeding section and the pair of liquid storage sections. .
By providing the switching portion in the liquid ejection head of the present invention, it is possible to replenish the liquid only to the liquid storage section that requires liquid replenishment. In addition, the provision of the switching section eliminates the need for a complicated design, enabling a space-saving and inexpensive head configuration.

<Other Sections>
Other parts are not particularly limited and can be appropriately selected according to the purpose. Examples thereof include a liquid volume detection part and a control part.

<<Liquid volume detector>>
The liquid volume detection section is a member that detects the liquid volume in the liquid holding section.
By providing the liquid amount detection section, it is possible to detect changes in the liquid amount due to not only ejection but also volatilization by detecting the amount of liquid in the liquid holding section, which is preferable. Further, the pair of switching units may be controlled based on the detection result of the liquid amount by the liquid amount detection unit. As a result, the liquid ejection head of the present invention can keep the amount of liquid in the liquid holding portion constant, so that the ejection can be more reliably stabilized.
Examples of the liquid volume detection unit include a sensor that counts the number of ejected droplets, an image sensor that captures an image of the liquid surface and detects the position of the liquid surface by image processing, a light emitting element and a position sensor, and a photoelectric sensor. A sensor-based water detection sensor and the like are included.
Further, it is preferable that at least the liquid level detection range of the liquid holding portion of the liquid ejection head is transparent.
A sensor for counting the number of droplets includes, for example, an ejection signal output counter in a controller equipped with a microcomputer.
Examples of sensors that take an image of the liquid surface and detect the position of the liquid surface by image processing include a camera, a capacitance type liquid level detection sensor, and a laser displacement meter from above when the liquid is opaque. be done.

In the liquid ejection head of the present invention, when the liquid in the liquid holding portion contains particles, the liquid in the liquid holding portion is stirred by feeding the liquid in the liquid holding portion into the liquid holding portion, thereby agitating the liquid in the liquid holding portion. can be redispersed, the particles can be prevented from clogging the ejection port, and the ejection can be stabilized.

Further, in the liquid discharge head of the present invention, the pair of liquid feeding sections transfer the liquid stored in one of the liquid storage sections to the liquid storage section, and also transfer the liquid from the liquid storage section to the other liquid storage section. You can let it run. As a result, the liquid ejection head of the present invention can adjust the amount of liquid in the liquid holding portion to keep the height of the liquid level constant, so that the ejection can be stabilized.

Further, the liquid ejection head of the present invention further includes a control section for controlling at least one of the pair of liquid transfer sections and the pair of switching sections so that the liquid level in the liquid holding section is constant. good too. Accordingly, the liquid ejection head of the present invention can stabilize ejection.

Further, when the liquid ejection head of the present invention includes a plurality of liquid holding portions, the amount of liquid transferred by at least one of the liquid holding portions is different from the amount of liquid transferred by the other liquid holding portions. You may make it control like this. As a result, the liquid discharge head of the present invention can perform appropriate stirring depending on the type of liquid even when the type of liquid in one of the liquid holding portions is different and the required stirring power is different. Ejection can be stabilized.

Further, the liquid ejection head of the present invention may further include a flow rate detection section for detecting the flow rate of the liquid in the liquid reservoir. Accordingly, the liquid ejection head of the present invention can more reliably stabilize ejection by controlling at least one of the pair of liquid feeding sections and the pair of switching sections based on the detection result of the flow rate detection section. .

Further, in the liquid ejection head of the present invention, liquid may be stored in advance in at least one of the pair of liquid storage portions. As a result, the liquid discharge head of the present invention can rapidly feed (supply) the liquid from at least one of the pair of liquid reservoirs to the liquid reservoir when the amount of liquid in the liquid reservoir is less than a predetermined value. can do.

Further, in the liquid discharge head of the present invention, when the amount of liquid in the liquid holding section is less than a predetermined value, control is performed to feed the liquid from at least one of the pair of liquid holding sections to the liquid holding section. may As a result, the liquid ejection head of the present invention can rapidly feed (supply) the liquid to the liquid holding portion.

Further, the liquid ejection head of the present invention may perform control so that the liquid is not transferred to the liquid sending section side rather than the switching section. As a result, the liquid discharge head of the present invention has a plurality of liquid holding portions, and even when the types of liquids held in the plurality of liquid holding portions are different, the different liquids are prevented from being mixed. be able to.

<<control section>>
The control section controls the pair of liquid feeding sections and the pair of switching sections so that the liquid level of the liquid held by the liquid holding section is constant.
The control unit has a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a main memory, etc., and performs various processes based on a control program for controlling the operation of the entire liquid ejection head. Execute.

Here, an embodiment of the liquid ejection head of the present invention will be described in more detail with reference to the drawings. However, the liquid ejection head of the present invention is not limited to these modes. In addition, in each drawing, the same code|symbol may be attached|subjected to the same component part, and the overlapping description may be abbreviate|omitted. Further, the number, positions, shapes, etc. of the constituent members described below are not limited to those described below, and the number, positions, shapes, etc., can be set to be preferable in carrying out the present invention.

FIG. 1A is a schematic diagram showing an example of the liquid ejection head of the invention, and FIG. 1B is a schematic diagram showing an example of the operation of the liquid ejection head of the invention.
As shown in FIG. 1A, the liquid ejection head 100 includes a nozzle plate 101, a vibrating member 111, a liquid holding section 121, liquid storage sections 131 and 132, liquid feeding sections 141 and 142, and a switching section (not shown). have.

In this embodiment, for convenience of explanation, the vibrating member 111 is used as a reference, the liquid holding portion 121 side of the vibrating member 111 is the upper side, the nozzle plate 101 side of the vibrating member 111 is the lower side, and the upper side of each part is the upper side. Let the bottom side be the bottom side.
Further, "planar view" means viewing an object from above or below, and "planar shape" means the shape of an object seen from above or below.

As shown in FIG. 1A, the nozzle plate 101 is provided with ejection openings 102 for ejecting a liquid 123 containing particles 124 held in a liquid holding portion 121 . Further, the vibrating member 111 includes a driving section 112 that drives the vibrating member 111 and a control section 113 that controls the driving section 112 .

Liquid holding portion 121 holds liquid 123 containing particles 124 (in which particles 124 are dispersed). In other words, the liquid holding portion 121 holds the liquid to be ejected from the ejection port 102 .
The liquid holding part 121 has an air opening part 122 whose upper surface is open to the atmosphere, so that the gas mixed in the liquid 123 can be released to the atmosphere. The liquid holding portion 121 is connected to at least one of liquid storage portions 131 and 132 to be described later so that the liquid 123 can flow therethrough.

The nozzle plate 101 is fixed to the lower end portion of the liquid holding portion 121 via the vibrating member 111 .
A discharge port (nozzle) 102 that is a through hole is formed in a portion of the nozzle plate 101 substantially at the center of the liquid holding portion 121 . The liquid 123 held in the liquid holding portion 121 is ejected as droplets from the nozzles 102 by the vibration of the nozzle plate 101 .

The vibrating member 111 is formed on the upper surface side of the nozzle plate 101 . That is, the vibrating member 111 is arranged on the side of the liquid holding portion 121 that holds the liquid 123 to be ejected from the ejection port 102 .

The driving section 112 drives the vibrating member 111 . The drive unit 112 can apply an ejection waveform (ejection signal) to the vibrating member 111 to vibrate the nozzle plate 101 to form droplets.
In other words, the driving section 112 applies a discharge waveform to the vibrating member 111 and controls the vibration state of the nozzle plate 101 to discharge the liquid 123 held in the liquid holding section 121 from the nozzle 102 as droplets. .

A pair of liquid feeding units 141 and 142 are connected to liquid storage units 131 and 132, respectively, and are members for sucking and discharging the liquid 123 in the liquid storage units between the liquid storage units 131 and 132 and the liquid storage unit 121. be.
When the liquid 123 is fed by the liquid feeding units 141 and 142, the liquid 123 stored in one of the liquid storage units 131 and 132 is caused to flow out to the liquid storage unit 121, and the liquid 123 is discharged from the one liquid storage unit. It is preferable that the flow rate of the liquid 123 flowing out to the liquid holding portion 121 is caused to flow from the liquid holding portion 121 into the other liquid storing portion. As a result, the liquid level of the liquid 123 held in the liquid holding portion 121 can be kept constant. Therefore, as in the present embodiment, the liquid 123 is discharged by the liquid pressure (static pressure) applied to the discharge port 102 by the liquid 123 contained in the liquid holding portion 121 and the movement (dynamic pressure) that displaces the discharge port 102 . In the liquid ejection head 100, the ejection can be stabilized by keeping the liquid pressure constant.
When the amount of the liquid 123 held in the liquid holding portion 121 is less than a predetermined value, the liquid sending portion preferably causes the liquid 123 to flow into the liquid holding portion 121 from at least one of the channels. As a result, the liquid ejection head 100 can supply the liquid 123 to the liquid holding portion 121, so that the liquid pressure can be kept constant and ejection can be stabilized.

The liquid storage units 131 and 132 are connected to the liquid storage unit 121 so as to allow the liquid 123 to flow therethrough, and can temporarily store the liquid 123 .
Also, the liquid reservoirs 131 and 132 are replaceable, and the capacity can be changed by adjusting the inner diameter and length. These two flow paths are inclined with respect to the nozzle 102 (nozzle plate 101). In other words, it is arranged at an angle with respect to the central axis passing through the nozzle 102 .
The liquid reservoirs 131 and 132 are arranged such that the extended line of the central axis of the connecting portion coincides with the corner formed by the nozzle plate 101 and the vibrating member 111 or is slightly closer to the nozzle 102 than the corner. It is preferred to

The switching units are arranged between the liquid feeding units 141 and 142 and the liquid storage units 131 and 132 respectively, and open and close the liquid storage units 131 and 132 . Details of the switching unit will be described later.

The control unit 113 controls the liquid feeding units 141 and 142 and the switching unit so that the liquid level of the liquid 123 held by the liquid holding unit 121 is constant.
The control unit 113 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a main memory, etc., and controls various operations based on a control program for controlling the operation of the entire liquid ejection head 100. Execute the process.

The control section 113 controls the liquid feeding sections 141 and 142 and the switching sections 151 and 152 so that the liquid level of the liquid 123 held by the liquid holding section 121 is constant.
The control unit 113 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), main memory, etc., and performs various processes based on a control program for controlling the operation of the entire liquid ejection apparatus. to run.

FIG. 1B is a schematic diagram showing an example of a process in which droplets are formed by the liquid ejection head. FIG. 1B schematically shows a state in which a discharge waveform is input from the driving section 112 to the vibrating member 111 and droplets 125 are formed by vibrating the nozzle plate 101 .
A portion of the nozzle plate 101 not in contact with the vibrating member 111 vibrates through the vibrating member 111 in accordance with the ejection waveform, and the amplitude of the ejection port 102 portion becomes the largest. Liquid 123 in liquid holding portion 121 is discharged as droplets 125 by vibration of discharge port 102 .

FIG. 2 is a schematic diagram showing an example of a state in which a liquid level detection section for detecting the liquid level height is arranged as a liquid level detection section for detecting the liquid level in the liquid holding section of the liquid ejection head.
The liquid level detection unit 161 always detects the liquid level height of the liquid 123 in the liquid holding unit 121, and feedback-controls the liquid feeding units 141 and 142 based on the detection result.
As shown in FIG. 2, an image sensor is provided as a liquid level detection section 161 capable of constantly detecting changes in the liquid level in the liquid holding section 121 of the liquid ejection head 100. When the liquid level deviates from a specified value, By controlling the switching of the discharge/suction operation of the pair of liquid feeding units (pumps) based on the detection results, the amount of liquid in the liquid holding unit 121 of the liquid ejection head 100 is kept constant, and the liquid level is maintained. can do.
The specified value of the liquid surface height when controlling the switching of the discharge/suction operation of a pair of liquid supply units (pumps) is the upper limit value, the lower limit value, or both, which can be operated externally using the SP mode of the control unit. It is also possible to have a configuration that can be set by the user.
In addition, if an output device for the detection result of the liquid level detection section is provided and the liquid level height can be digitally displayed on the operation section, the operator can always check the liquid level change in the liquid holding section of the head. can.
Furthermore, by providing an LED lamp or the like, it is possible to emit light to indicate when the liquid level deviates from the specified value, according to the signal from the output device of the detection result of the liquid level detection means.

Normally, one of a pair of liquid feeding units performs a suction operation and the other performs a discharging operation at the same time. The liquid in the liquid holding part is stirred while the liquid level of the liquid holding part is kept constant.
However, the amount of liquid in the liquid holding portion decreases as the liquid discharge continues, or the liquid level in the liquid holding portion decreases due to volatilization of the liquid in the liquid holding portion.
Therefore, the reduced liquid amount ΔS is detected from the change in the liquid level in the liquid holding portion detected by the liquid level detecting portion during the ejection operation, and the supply amount is increased by ΔS from the discharge amount at the next operation of the liquid feeding means. With such control, a reduced amount of liquid can be supplied, so that the position of the liquid surface can be maintained at all times.

3A to 3C are explanatory diagrams showing an example of the stirring operation of the liquid in the liquid holding section using the liquid feeding section 1. FIG.
More specifically, FIG. 3A is an explanatory diagram showing an example of a state when the liquid 123 containing the particles 124 is placed in the liquid holding portion 121 and left standing. In FIG. 3A, the particles 124 settle and accumulate on the bottom of the liquid holding portion 121 due to the free sedimentation of the particles 124 . If the droplet ejection operation is performed in this state, the particles 124 are aggregated in the vicinity of the ejection port 102, so that the ejection port 102 is clogged with the aggregated particles 124, and no droplet is formed. Failure to do so may result in malfunction.
Also, even if a droplet can be formed, the initial droplet contains a large amount of particles 124 and is ejected, and the content of the particles 124 contained in the droplet gradually decreases. Therefore, when the particles 124 above the ejection port 102 are ejected, only the supernatant liquid is ejected, and there is a problem that the content of the particles 124 in the droplet 125 varies greatly over time. be.

3B and 3C are explanatory diagrams showing an example of the redispersion process of the particles 124 by stirring the liquid 123 held in the liquid holding section 121 using the liquid feeding sections 141 and 142. FIG.
First, as shown in FIG. 3A, one of the liquid feeding units 141 and 142 performs a suction operation in advance to create a negative pressure state in the flow path, thereby removing a certain amount of the liquid 123 in the liquid holding unit 121. Aspirate and hold. In this embodiment, an example in which the liquid feeding unit 141 sucks and holds is shown.

FIG. 3B is a diagram showing an example of a state in which the liquid feeding section 141 performs a discharge operation and the liquid feeding section 142 performs a suction operation.
By the discharging operation of the liquid feeding section 141 , the inside of the liquid storing section 131 is brought into a positive pressure state, and the liquid 123 sucked and held is discharged into the liquid holding section 121 . The discharged liquid 123 forms a flow substantially parallel to the central axis of the portion where the liquid reservoir 131 is connected to the liquid holder 121, and the particles 124 accumulated in the corner formed by the nozzle plate 101 and the vibrating member 111 are removed. An upward flow along the wall surface of the liquid holding portion 121 causes the liquid to rise above the liquid holding portion 121 .
Further, the liquid feeding section 142 performs a suction operation to make the inside of the liquid storage section 132 into a negative pressure state, thereby sucking and holding a certain amount of the liquid 123 in the liquid holding section 121 .

Subsequently, as shown in FIG. 3C , the liquid feeding unit 142 performs a discharging operation to bring the inside of the liquid storage unit 131 into a positive pressure state and discharge the liquid 123 sucked and held into the liquid holding unit 121 . The discharged liquid 123 causes an upward flow again in the liquid holding section 121 , and has the effect of whirling up the particles 124 above the liquid holding section 121 .
By repeating the above operation, it is possible to re-disperse the particles 124 that have settled on the bottom of the liquid holding portion 121 with a small amount of liquid. By performing the droplet forming operation in a re-dispersed state, it is possible to prevent non-ejection due to sedimentation of the particles 124 and change in concentration of the particles 124 contained in the ejected droplets 125 over time. .

If the liquid storage section 131 and the liquid storage section 132 are arranged on one side with respect to the central axis passing through the ejection port 102, the distribution of the particles 124 in the liquid holding section 121 is uneven. is preferred.
In order to uniformly disperse the particles 124 in the liquid holding portion 121, the liquid feeding portions 141 and 142 must have the same suction speed, discharge speed, suction liquid amount, and discharge liquid amount. values are preferred.

4A to 4C are explanatory diagrams showing an example of alternate operation of the liquid feeding units.
FIG. 4A shows an example of a state in which liquid 123 is held in advance in liquid storage section 131 connecting liquid feeding section 141 and liquid holding section 121 while both liquid feeding section 141 and liquid feeding section 142 are stopped. ing.

FIG. 4B shows an example of the state when the liquid sending unit 141 performs the discharging operation, generates a stirring flow in the liquid 123 in the liquid holding unit 121, and redisperses the particles 124 contained in the liquid 123. showing. At this time, since the liquid feeding portion 142 is stopped, the liquid 123 previously sucked into the liquid storing portion 131 flows into the liquid holding portion 121, and the liquid amount of the liquid 123 in the liquid holding portion 121 increases. and the liquid level rises.

FIG. 4C shows an example of a state in which the liquid feeding section 142 performs the suction operation after the liquid feeding section 141 completes its operation. By sucking the amount of liquid that has flowed into the liquid holding portion 121 by the liquid feeding portion 142 and holding it in the liquid storing portion 132, the liquid amount of the liquid 123 in the liquid holding portion 121 decreases and the liquid level drops. You can revert to the previous state.

FIG. 5 is an explanatory diagram showing an example of transition of the liquid level height of the liquid holding section when the liquid feeding section operates alternately.
Contrary to the examples shown in FIGS. 3B and 3C, when the discharging operation is performed by the other liquid feeding means after the suction operation by one liquid feeding means is performed, the liquid level in the liquid holding portion 121 is lowered once. After that, it rises and returns to the state before the operation.
In the case of redispersing the particles 124 that have settled while the ejection of droplets from the ejection port 102 is stopped, the redispersion can be performed by this operation.

On the other hand, the agitation of the liquid 123 is generally expected to have the effect of suppressing sedimentation of the dispersed particles 124 in addition to redispersion of the sedimented particles 124 .
By executing the stirring operation in the liquid holding unit 121 during the droplet ejection operation shown in FIGS. 3A to 3C, the sedimentation of the particles 124 is suppressed, and the droplets are ejected while always maintaining a uniform dispersion state. It is possible to maintain a constant concentration of particles contained in droplet 125 over time.

However, when the liquid feeding section 141 and the liquid feeding section 142 operate alternately as shown in FIG. The water pressure applied to the nozzle plate 101 changes, and the falling speed of the ejected droplets 125 also changes.
This is good when the droplets 125 are continuously ejected at one point, but when the droplets 125 are arranged at regular intervals, generally the liquid ejection head or the droplets 125 are placed. A discharge operation is performed at a constant cycle while moving the droplet holding member at a constant speed. Therefore, when the falling speed of the droplet 125 changes, the landing position of the droplet 125 changes, and the intervals between the droplets 125 on the droplet holding member are not uniform.
As shown in FIG. 5, the suction operation of the liquid sending unit 142 is performed in synchronization with the discharging operation of the liquid sending unit 141, or the discharging operation of the liquid sending unit 142 is performed in synchronization with the suction operation of the liquid sending unit 141. , the liquid 123 can be stirred while the liquid volume in the liquid holding portion 121 is kept constant.

FIG. 6 is a schematic diagram showing an example of a plan view of part of the liquid ejection head 100 of the present invention.
As shown in FIG. 6, when a portion of the liquid ejection head 100 is viewed from above, the adjacent liquid holding portions 121a and 121b are connected via liquid storage portions 131a and 131b and liquid storage portions 132a and 132b. . A pair of switching portions 151 and 152 are provided at the branch point of the liquid storage portions 131a and 131b and the branch point of the liquid storage portions 132a and 132b.
Here, the switching units 151 and 152 will be described in detail with reference to FIGS. 7A to 7C.
7A to 7C are schematic diagrams showing an example of the operation of the switching section in the liquid ejection head of the present invention. 7A to 7C show an example of using a three-way valve as a switching section when two liquid holding sections are connected to one liquid feeding section as shown in FIG. .
7A shows a state in which the liquid storage section 131a and the liquid delivery section 141 in FIG. 6 are connected, FIG. 7B shows a state in which the liquid storage section 131b and the liquid delivery section 141 in FIG. 6 are connected, and FIG. It shows a state in which both the liquid storage portions 131a and 131b and the liquid feeding portion 141 in FIG. 6 are connected. Thus, by providing the switching portion at the branch point of the liquid storage portion, it is possible to select and switch the liquid storage portion for sucking and discharging the liquid. As the switching unit, other means such as a configuration in which an electromagnetic valve or the like is provided in each liquid storage section to switch opening and closing of the liquid storage section may be used.
As shown in FIGS. 7A and 7B, when only one of the liquid storage units 131a and 131b is connected, the liquid supply unit is controlled by a liquid supply amount that allows stirring of only one liquid storage unit. If both the liquid reservoirs 131a and 131b are connected as in the state of 7C, a flow rate necessary for stirring the two liquid reservoirs is required, so only one of the liquid reservoirs 131a and 131b is connected. By driving and controlling the liquid feeding unit, the liquid can be fed at twice the liquid feeding amount as compared with the case where the liquid is fed.
As shown in FIGS. 7A to 7C, by providing a switching portion at the branch point of the liquid reservoirs, one liquid reservoir can be closed by a valve to open the other liquid reservoirs. The switching timing can be controlled more easily than when a valve as a switching section is arranged independently in each liquid storage section. Further, as shown in FIGS. 7A to 7C, by providing a switching section at the branch point of the liquid reservoirs, there is no need to provide a switching section independently for each liquid reservoir. The number of valves can be reduced. In addition, as shown in FIGS. 7A to 7C, by providing a switching section at the branch point of the liquid storage section, a complicated design becomes unnecessary, and a space-saving and inexpensive head can be obtained.

Further, when the liquid agitation of the two liquid holding parts is performed by a pair of liquid feeding parts, the two liquid feeding parts communicate with the liquid holding part and simultaneously feed the same amount of liquid. When the two liquid holding parts operate under different ejection conditions or when the types of liquid are different, the amount of decrease in the liquid level in the two liquid holding parts is different. occurs.
Therefore, when the liquid level detection unit detects that the liquid level in one of the liquid holding units is lower than the reference level, the liquid level is maintained (restored) by the amount of the drop in the liquid level. An operation is performed to increase the amount of liquid discharged from the storage section to the liquid holding section. However, since the liquid feeding portion is also connected to the other liquid holding portion, if there is no switching portion for switching between the liquid holding portions, the liquid will be excessively fed to the other liquid holding portion. , the liquid level rises above the standard.
In the liquid ejection head of the present invention, since the liquid storage section that connects the liquid feeding section and the liquid holding section is provided with the switching section, when the discharging operation for recovering the liquid level height is performed, the liquid discharge head shown in FIG. 7A or FIG. As shown in 7B, by connecting (switching) the liquid feeding unit only to the liquid storage unit that connects the liquid holding unit with the lowered liquid level, the liquid is discharged only to the liquid holding unit with the lowered liquid level. Therefore, the liquid level can be maintained (restored).

(Droplet forming device and droplet forming method)
The droplet forming apparatus of the present invention has the liquid ejection head of the present invention and, if necessary, other means.
Since the droplet forming apparatus of the present invention has the liquid ejection head of the present invention, it is possible to stabilize ejection of droplets.
The droplet forming method of the present invention is a droplet forming method capable of forming droplets, and uses the liquid ejection head of the present invention to dispense liquid between a liquid reservoir and a liquid holding section. a step of feeding a liquid to each of a liquid storage portion and a liquid holding portion by a pair of liquid feeding portions for feeding a liquid; and a step of switching the liquid storage portion by a pair of switching portions; and other steps.
The droplet forming method of the present invention can be suitably carried out by using the liquid ejection head of the present invention, and the step of feeding the liquid to each of the liquid storage section and the liquid holding section is performed by a pair of liquid feeding sections. The process of switching the liquid reservoir can be suitably performed by a pair of switching parts, and the other processes can be performed by other means.
The "liquid holding section", "liquid storage section", "liquid feeding section" and "switching section" in the droplet forming apparatus and droplet forming method of the present invention are the same as those of the liquid ejection head of the present invention. Therefore, the description is omitted. Also, each step in the droplet formation method of the present invention is the same as the description of the operation of the liquid ejection head of the present invention, so the description is omitted.

(dispensing device)
The dispensing device of the present invention has the droplet forming device of the present invention and, if necessary, particle number counting means and other means.
Since the dispensing apparatus of the present invention can stabilize ejection by having the droplet forming apparatus of the present invention, it is possible to reduce variations in the amount of liquid containing the ejected droplets.

<Particle number counting means>
The particle number counting means is means for counting particles contained in a droplet, and the number of particles contained in the droplet is counted by a sensor after the droplet is ejected and before the droplet lands on the object to be adhered. Preferably, it is a means for
Sensors are used to capture the mechanical, electromagnetic, thermal, acoustic, or chemical properties of natural phenomena and artifacts, or the spatial and temporal information indicated by them, by applying some scientific principles to human beings and human beings. It means a device that replaces a signal of another medium that is easy for a machine to handle.

The particle number counting means is not particularly limited and can be appropriately selected according to the purpose, and may include a process of observing particles before discharge and a process of counting particles after landing.

Counting the number of particles contained in the droplet after the droplet is ejected and before the droplet lands on the object to be adhered ensures that the droplet enters the well of the plate as the object to be adhered. It is preferable to observe the particles in the droplet at a timing that is directly above the expected well opening.

The plate is not particularly limited, and a plate having holes generally used in the biotechnology field can be used.
The number of wells in the plate is not particularly limited and can be appropriately selected depending on the purpose, and may be singular or plural.
As a plate having a plurality of wells, it is preferable to use a plate having holes formed in the number and dimensions generally used in the industry, such as 24, 96, or 384 wells.
The material of the plate is not particularly limited and can be appropriately selected according to the purpose, but it is preferable to use a material that suppresses adhesion of cells or nucleic acids to the wall surface for later treatment.

Methods for observing particles in droplets include, for example, an optical detection method, an electric/magnetic detection method, and the like.

<Other means>
Other means are not particularly limited and can be appropriately selected according to the purpose. For example, it is preferable to have control means, display means, recording means, and the like.

As described above, the liquid ejection head of the present invention includes an ejection port, a liquid holding portion, a pair of liquid storage portions, a pair of liquid feeding portions, and a pair of switching portions. A pair of liquid feeding units and a pair of switching units are controlled so that the liquid level height of the liquid held by the liquid holding unit is constant, and the liquid held by the liquid holding unit is fed and agitated to discharge the liquid. can be stabilized. Similar effects can also be obtained in a droplet forming apparatus and a dispensing apparatus having this liquid ejection head.

Aspects of the present invention are, for example, as follows.
<1> a discharge port;
a liquid holding part that holds the liquid to be discharged from the discharge port;
a pair of liquid storage units respectively connected to the liquid storage unit so as to allow the liquid to flow therethrough and storing the liquid;
a pair of liquid feeding units connected to the pair of liquid storage units and feeding the liquid between the liquid storage unit and the liquid holding unit;
a pair of switching units arranged between the liquid feeding unit and the liquid storage unit and switching between the liquid storage units that deliver the liquid;
It is a liquid ejection head characterized by having
<2> The liquid ejection head according to <1>, wherein the switching unit is a three-way valve.
<3> The liquid ejection head according to any one of <1> to <2>, further including a vibrating member for ejecting the liquid held by the liquid holding portion from the ejection port.
<4> The liquid ejection head according to any one of <1> to <3>, further including a liquid amount detection unit that detects the amount of liquid in the liquid holding unit.
<5> The liquid according to any one of <1> to <4>, further comprising a control section that controls opening and closing of the pair of switching sections based on the detection result of the liquid level height detected by the liquid amount detection section. It is an ejection head.
<6> The pair of liquid feeding units feeds the liquid stored in one of the liquid storage units to the liquid storage unit, and transfers the liquid from the liquid storage unit to the other liquid storage unit. The liquid ejection head according to <1> or <5>, which sends liquid.
<7> The above <1> to <6, wherein the control unit controls at least one of the pair of liquid feeding units and the pair of switching units so that the liquid level in the liquid holding unit is constant. > is the liquid ejection head according to any one of the above.
<8> having a plurality of liquid holding portions,
One of the liquid holding parts is a pair of liquid reservoirs in which one of the liquid storage parts is connected to the liquid delivery part, and a plurality of the other liquid storage parts are connected to the other liquid delivery part. Department and
the same number of the pair of switching units as the pair of liquid storage units;
has
By controlling the pair of liquid feeding units and the pair of switching units in the same number as the pair of liquid storage units, at least one of the plurality of liquid holding units is selectively fed. The liquid ejection head according to any one of 1> to <7>.
<9> The liquid ejection according to <8>, wherein the amount of the liquid transferred by at least one of the liquid holding portions is controlled so as to be different from the amount of the liquid transferred by the other liquid holding portions. is the head.
<10> further comprising a flow rate detection section for detecting the flow rate of the liquid in the liquid storage section;
The liquid ejection head according to any one of <1> to <9>, wherein at least one of the pair of liquid transfer sections and the pair of opening/closing sections is controlled based on the detection result of the flow rate detection section.
<11> The liquid ejection head according to any one of <1> to <10>, wherein the liquid is stored in advance in at least one of the pair of liquid storage portions.
<12> When the amount of the liquid in the liquid holding portion is less than a predetermined value,
The liquid ejection head according to any one of <1> to <11>, which performs control to feed the liquid from at least one of the pair of liquid storage sections to the liquid holding section.
<13> The liquid ejection head according to any one of <1> to <12>, wherein control is performed so that the liquid is not sent to the liquid transfer section side of the switching section.
<14> The liquid ejection head according to any one of <1> to <13>, wherein the liquid contains particles.
<15> A droplet forming apparatus including the liquid ejection head according to any one of <1> to <14>.
<16> A dispensing device comprising the droplet forming device according to <15>.
<17> A droplet forming method capable of forming droplets,
Using the liquid ejection head according to any one of <1> to <14>,
The liquid is fed to the liquid storage section and the liquid holding section by a pair of liquid feeding sections that feed the liquid between the liquid storage section that stores the liquid and the liquid holding section. process and
a step of switching the liquid storage section by the pair of switching sections;
A method for forming droplets, comprising:

The liquid ejection head according to any one of <1> to <14>, the droplet forming device according to <15>, the dispensing device according to <16>, and the dispensing device according to any one of <17>. According to the droplet formation method of 1, the above problems in the conventional art can be solved and the object of the present invention can be achieved.

JP 2016-116489 A

REFERENCE SIGNS LIST 100 liquid ejection head 101 nozzle plate 102 ejection port 111 vibration member (displacement portion)
112 drive unit 113 control unit 121 liquid holding unit 123 liquid 125 droplet 131, 132 liquid storage unit 141, 142 liquid sending unit 151, 152 switching unit 161 liquid amount detection unit

Claims (7)

a discharge port;
a liquid holding part that holds the liquid to be discharged from the discharge port;
a pair of liquid storage units respectively connected to the liquid storage unit so as to allow the liquid to flow therethrough and storing the liquid;
a pair of liquid feeding units connected to the pair of liquid storage units and feeding the liquid between the liquid storage unit and the liquid holding unit;
a pair of switching units arranged between the liquid feeding unit and the liquid storage unit and switching between the liquid storage units that deliver the liquid;
A liquid ejection head comprising: 2. The liquid ejection head according to claim 1, wherein the switching portion is a three-way valve. 3. The liquid ejection head according to claim 1, further comprising a vibrating member for ejecting the liquid held by the liquid holding portion from the ejection port. 4. The liquid ejection head according to any one of claims 1 to 3, further comprising a liquid amount detection section that detects the amount of liquid in the liquid holding section. A droplet forming apparatus comprising the liquid ejection head according to any one of claims 1 to 4. A dispensing device comprising the droplet forming device according to claim 5 . A droplet forming method capable of forming droplets,
Using the liquid ejection head according to any one of claims 1 to 4,
The liquid is fed to the liquid storage section and the liquid holding section by a pair of liquid feeding sections that feed the liquid between the liquid storage section that stores the liquid and the liquid holding section. process and
a step of switching the liquid storage section by the pair of switching sections;
A droplet forming method comprising:

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