JP4165420B2 - Electrostatic actuator, method for manufacturing electrostatic actuator, droplet discharge head using these, method for manufacturing droplet discharge head, and droplet discharge apparatus - Google Patents

Description

The present invention relates to an electrostatic actuator provided with an electromechanical transducer having a diaphragm portion and electrodes arranged opposite to each other at a predetermined interval, a method for manufacturing the electrostatic actuator, a droplet discharge head using these, a liquid discharge head, and a liquid The present invention relates to a method for manufacturing a droplet discharge head and a droplet discharge device.

An ink jet head as a droplet discharge head including an electrostatic actuator having a diaphragm portion and electrodes arranged to face each other at a predetermined interval has attracted attention from the viewpoints of downsizing and low voltage driving.

This electrostatic actuator applies a DC driving voltage between a diaphragm (diaphragm) and an electrode (individual electrode) facing the diaphragm, so that the diaphragm is applied to the electrode by electrostatic force (Coulomb force). When the drive voltage is released, the diaphragm is returned to its original position. The ink jet head pressurizes the liquid filled in the chamber facing the vibration plate portion using the displacement of the vibration plate portion, and discharges the liquid droplets from the nozzle.

As a method for driving the ink jet head, a flow path substrate on which a plurality of ink flow paths, nozzles, and a vibration plate portion are formed, and individual electrodes that are disposed to face the vibration plate portion and have a predetermined interval are provided. And the flow path substrate is made of P-type silicon, and B + (boron ion) is formed on the flow path substrate.
There is known a method of driving an ink-jet head obtained by diffusing 1 × 10E19 / cubic cm or more.

In this case, the flow path substrate is grounded to the GND potential, and a pulse voltage that changes from the GND potential to the + potential is applied to the individual electrode to deform the vibration plate portion, and ink is ejected from the nozzle to perform recording (
Patent Document 1).

In an inkjet head having such an electrostatic actuator, an insulating film (layer) that electrically prevents a short circuit between the vibration plate portion and the electrode is formed between the vibration plate portion and the electrode facing the vibration plate portion. When the diaphragm part is made of a semiconductor material, this insulating film (layer) functions as a dielectric, and it is known that a charge remains and is charged between the diaphragm part and the electrode by applying a driving voltage for a long time. (Patent Document 2).

In addition to this insulating film (layer), a dielectric may be present. For example, in order to prevent the diaphragm portion and the electrode from coming into close contact with each other, the HMDS (Hexa) treated with each surface is prevented.
Methyl Di Silazane) and other hydrophobically treated membranes and moisture adsorbed on the surface are charged by an electric field during driving (literature related to HMDS; Patent Document 3).

If charging occurs between the diaphragm and the electrode, the relative displacement between the diaphragm and the electrode changes due to the electric field generated by this charging, resulting in ejection characteristics (e.g., ejected ink mass and ink speed). Changes and affects print quality. Therefore, in the manufacturing process of the ink jet head, a print inspection or the like is performed to determine whether the charge amount is within a predetermined range, and the product is commercialized.

Further, when driving an ink jet printer equipped with this ink jet head, a voltage having a polarity different from the voltage at the time of driving is applied at a predetermined cycle to remove the electrostatic charge between the diaphragm portion and the electrode. It is known to perform actuator refresh processing (Patent Document 4).

Japanese Patent Laid-Open No. 10-181011 JP 7-81088 A Japanese Patent Laid-Open No. 10-18028 JP-A-7-214775

In such a conventional ink jet head, it is necessary to inspect whether or not the charge amount between the diaphragm portion and the electrode is within a predetermined range as described above, and the manufacturing yield is not easily improved. Therefore, in the manufacturing process of the inkjet head provided with the electrostatic actuator,
There is a need for a technique for accurately grasping the amount of charge due to the residual charge between the diaphragm portion and the electrode, and for judging the quality of the product based on this and feeding it back to the manufacturing process.

The present invention has been made in consideration of the above-mentioned problems, and has established a technique for quantifying the amount of charge between the diaphragm portion and the electrode, and provides an electrostatic actuator, It is an object of the present invention to provide an actuator manufacturing method, a droplet discharge head using these, a method of manufacturing a droplet discharge head, and a droplet discharge device.

The method for measuring the amount of charge of an electrostatic actuator according to the present invention is a method for measuring the amount of charge of an electrostatic actuator having an electromechanical conversion element having a diaphragm part and an electrode opposed to the diaphragm part at a predetermined interval. In the method, a measurement step of measuring a capacitance between the diaphragm portion and the electrode while applying a bias voltage between the diaphragm portion and the electrode, and a specific value within a region in which the capacitance is minimum And a calculation step of obtaining a charge amount charged between the diaphragm portion and the electrode from a bias voltage when taking the voltage. Here, the “minimum neighborhood region” refers to a predetermined region in the minimum neighborhood including the minimum.

According to this configuration, in the measurement step, the electrostatic capacitance between the diaphragm portion and the electrode is measured while applying a bias voltage between the diaphragm portion and the electrode, and in the calculation step, the electrostatic capacitance is measured. The amount of charge between the diaphragm and the electrode is quantified by obtaining the amount of charge charged between the diaphragm and the electrode from the bias voltage when taking a plurality of specific values in the minimum neighborhood region be able to.

In this case, in the measurement step, the electrostatic capacitance between the diaphragm portion and the electrode with respect to the bias voltage is measured at a plurality of points, and in the calculation step, the bias voltage and the bias voltage are determined by the least square method based on the capacitance measured at the plurality of points. It is preferable to approximate the relationship with the capacitance as a quadratic curve, and obtain the charge amount from the bias voltage when the quadratic curve takes a specific value within the minimum vicinity region.

According to this configuration, the relationship between the bias voltage and the capacitance is approximated as a quadratic curve by the least square method based on the capacitance measured at a plurality of points, and the quadratic curve is a specific region within the minimum neighborhood region. Since the charge amount is obtained from the bias voltage when taking a plurality of values, the charge amount between the diaphragm portion and the electrode can be reliably quantified. If the measurement process and the calculation process are repeated, a more accurate charge amount can be obtained.

In this case, in the calculation process, when the relationship between the bias voltage and the capacitance is approximated as a quadratic curve, measured values of the rising portion and the falling portion where the diaphragm portion is suddenly displaced by applying the bias voltage. It is preferable to approximate except.

According to this configuration, the relationship between the bias voltage and the capacitance approximated as a quadratic curve is obtained by excluding measured values at the rising and falling portions where the diaphragm portion is suddenly displaced by applying the bias voltage. Since it is approximated, the amount of charge between the diaphragm portion and the electrode can be obtained by accurately grasping the change in capacitance due to the charge between the diaphragm portion and the electrode.

The method for manufacturing an electrostatic actuator according to the present invention is the above method for manufacturing an electrostatic actuator including an electromechanical conversion element having a diaphragm portion and an electrode disposed opposite to the diaphragm portion at a predetermined interval. A measuring step of measuring the amount of charge charged between the diaphragm portion and the electrode using the method for measuring the amount of charge of the electrostatic actuator of the invention, and the driving voltage of the electrostatic actuator to a value corresponding to the measured amount of charge And an adjusting step for adjusting.

According to this configuration, in the measurement step, the charge amount charged between the diaphragm portion and the electrode is measured using the method for measuring the charge amount of the electrostatic actuator according to the invention described above, and in the adjustment step, the electrostatic actuator is driven. Since the voltage is adjusted to a value corresponding to the measured charge amount, an appropriate driving voltage for the electrostatic actuator corresponding to the charge amount charged between the diaphragm and the electrode can be set. Therefore, an electrostatic actuator having stable driving characteristics can be manufactured.

In this case, it is preferable to further include a determination step of determining whether or not the measured charge amount indicates an abnormal value, and when determining that the measured charge amount indicates an abnormal value, this electrostatic actuator is excluded as a failure.

The method of manufacturing a droplet discharge head according to the present invention includes a diaphragm portion and an electrostatic actuator having an electromechanical conversion element having a diaphragm portion and an electrode disposed opposite to the diaphragm portion at a predetermined interval. In a method of manufacturing a droplet discharge head that discharges droplets from a nozzle by pressurizing a liquid filled in a discharge chamber that faces the droplet, the droplet discharge head includes a liquid flow that includes an electrostatic actuator and a discharge chamber. The electrostatic actuator according to the present invention has a droplet discharge portion in which a plurality of passages and nozzles communicating with the discharge chamber are formed. Measurement step using the above charge amount measurement method, adjustment step for adjusting the driving voltage of the electrostatic actuator in the method for manufacturing the electrostatic actuator of the invention, or whether the charge amount of the invention shows an abnormal value Or it determines, characterized by comprising a determination step that eliminates the electrostatic actuator as defective if indicating an abnormal value.

According to this configuration, it is considered that the electrostatic actuator formed in a plurality of sections of the droplet discharge portion has substantially the same level of charge. Therefore, in the measurement process, the charge amount of one of the plurality of electrostatic actuators can be measured, and in the adjustment process, the drive voltage of the electrostatic actuator can be set to a value corresponding to the charge amount. Alternatively, in the determination step, an electrostatic actuator having an abnormal charge amount can be detected and eliminated. Therefore, a droplet discharge head including an electrostatic actuator having stable driving characteristics can be manufactured.

In this case, it is preferable that the droplet discharge unit has at least one dummy electrostatic actuator, and in the measurement step, the charge amount between the diaphragm portion of the dummy electrostatic actuator and the electrode is measured.

According to this configuration, since the droplet discharge unit has the dummy electrostatic actuator for measuring the charge amount, it is not necessary to measure the charge amount using the electrostatic actuator that pressurizes the original liquid. Also good. Also, in the measurement process, when a bias voltage is applied between the diaphragm and the electrode within the upper and lower voltage ranges that can drive the electrostatic actuator, there is a risk that the original electrostatic actuator will be degraded by the applied bias voltage. Can be avoided.

According to another method of manufacturing a liquid droplet ejection head of the present invention, an electrostatic actuator including an electromechanical conversion element having a vibration plate portion and an electrode disposed opposite to the vibration plate portion with a predetermined interval is provided. In a manufacturing method of a droplet discharge head that pressurizes a liquid filled in a discharge chamber located facing a vibration plate portion and discharges a droplet from a nozzle, a wafer-like first substrate on which an electrode is formed;
A plurality of droplet discharge heads are formed on the wafer-like laminate obtained by bonding the wafer-like second substrate on which the vibration plate portion is formed, and droplet discharge is performed. A manufacturing step of forming at least one dummy electrostatic actuator in a region other than the formation region of the head, and a cutting step of cutting out the plurality of droplet discharge heads from the wafer-like laminate,
A measurement step of measuring at least one charge amount of the dummy electrostatic actuator with respect to the droplet discharge head obtained by the cutting step by using the charge amount measurement method of the electrostatic actuator of the invention; An adjustment step for adjusting the driving voltage of the electrostatic actuator in the method for manufacturing the electrostatic actuator or whether or not the charge amount of the invention shows an abnormal value,
And a determination step of eliminating the electrostatic actuator as defective when an abnormal value is indicated.

According to this configuration, in the manufacturing process, by joining the wafer-like first substrate on which the electrode is formed and the second substrate on which the vibration plate portion is formed, the region other than the region where the droplet discharge head is formed At least one dummy electrostatic actuator is formed in the region, and in the measurement step, the charge amount of the dummy electrostatic actuator is measured. Therefore, the charge amount measurement result can be replaced with the original charge amount of the electrostatic actuator. When applying a bias voltage between the diaphragm and the electrode within the upper and lower voltage ranges in which the electrostatic actuator can be driven in the measurement process, the risk of degrading the original electrostatic actuator due to the applied bias voltage Can be avoided. In addition, it is possible to grasp the variation in the charge amount by using a plurality of droplet discharge heads including electrostatic actuators formed in wafer units as one manufacturing lot.

The electrostatic actuator of the present invention is manufactured using the method for manufacturing an electrostatic actuator of the present invention. According to this, a measurement step of measuring the charge amount between the diaphragm portion of the electrostatic actuator and the electrode, and an adjustment step of adjusting the drive voltage of the electrostatic actuator to a value corresponding to the measured charge amount, Or since the determination process which excludes the electrostatic actuator in which charge amount shows an abnormal value as a defect is provided, the electrostatic actuator which has the stable drive characteristic can be provided.

The droplet discharge head of the present invention is manufactured using the method for manufacturing a droplet discharge head of the above invention. According to this, since the electrostatic actuator having a stable driving characteristic is provided, a droplet discharge head having a stable discharge characteristic can be provided.

In addition, another droplet discharge head of the present invention includes a vibration plate portion by an electrostatic actuator including an electromechanical conversion element having a vibration plate portion and an electrode disposed opposite to the vibration plate portion at a predetermined interval. In a droplet discharge head that pressurizes a liquid filled in a discharge chamber located facing and discharges droplets from a nozzle, an electrostatic actuator, a liquid flow path including the discharge chamber, and a nozzle communicating with the discharge chamber And a droplet discharge section having a plurality of sections, and the droplet discharge section is provided with at least one dummy electrostatic actuator for measuring a charge amount between the vibration plate section and the electrode. And

According to this configuration, the droplet discharge unit constituting the droplet discharge head includes a plurality of electrostatic actuators and a dummy electrostatic actuator for measuring the amount of charge between the diaphragm and the electrode. Therefore, the charge amount between the vibration plate portion and the electrode of the dummy electrostatic actuator can be measured and replaced with the charge amount between the vibration plate portion and the electrode of the original electrostatic actuator that pressurizes the liquid. In addition, it is possible to avoid the risk of deteriorating the original electrostatic actuator due to the influence of a bias voltage or the like applied when measuring the charge amount.

The liquid droplet ejection apparatus of the present invention is equipped with the liquid droplet ejection head of the above invention. According to this, since a droplet discharge head having stable discharge characteristics is mounted, a droplet discharge device having high discharge quality can be provided.

The droplet discharge device of the present invention is a recording device such as an ink jet printer using ink as a liquid, or a substrate from a droplet discharge head using a functional liquid such as a color filter material, a light emitting material, or a metal wiring material as a liquid. It includes a drawing device that draws the color filter layer, the light emitting layer, the metal wiring, and the like made of the functional liquid by discharging onto the (work).

The wafer-like laminate of the present invention faces the vibration plate portion by an electrostatic actuator having an electromechanical transducer having a vibration plate portion and electrodes opposed to the vibration plate portion at a predetermined interval. A wafer-like first substrate on which electrodes are formed in a wafer-like laminate in which a plurality of droplet ejection heads that pressurize a liquid filled in an ejection chamber located at a position and eject droplets from a nozzle are formed A wafer-like second substrate on which a liquid flow path serving as a vibration plate portion and a discharge chamber is formed, and a wafer-like third substrate on which a nozzle is formed, and the wafer-like first substrate And at least one dummy electromechanical conversion element for specifying the charge amount of the electrostatic actuator is formed in an area other than the formation area of the droplet discharge head by bonding the wafer and the wafer-like second substrate. And

According to this configuration, the wafer-like laminate includes the dummy electromechanical conversion element for specifying the amount of charge between the diaphragm portion of the electrostatic actuator and the electrode, the first wafer-like substrate and the first substrate. 2
At least one of them is formed by bonding the substrate to the substrate, so that by measuring the amount of charge between the diaphragm portion of the dummy electromechanical conversion element and the electrode, a partition is formed on the wafer-like substrate. In addition, it can be replaced with the amount of charge between the vibration plate portion of the electrostatic actuator and the electrodes constituting the plurality of droplet discharge heads. In addition, since the dummy electromechanical transducer is provided in a region other than the region where the droplet ejection head is formed, the droplet ejection head can be compared with the case where the dummy electromechanical transducer is provided in the droplet head. The size can be reduced, and the use area efficiency of the wafer-like laminate can be increased.

The present invention relates to an electrostatic charge measuring device for an electrostatic actuator having an electromechanical transducer element having a diaphragm part and an electrode disposed opposite to the diaphragm part at a predetermined interval. A power supply unit for applying a predetermined bias voltage between them, a capacitance measuring unit for measuring the capacitance between the diaphragm unit and the electrode to which the bias voltage is applied, and capacitance measurement of the capacitance measuring unit And a calculation unit that calculates a charge amount between the diaphragm unit and the electrode from a bias voltage when the capacitance takes a plurality of specific values in the minimum vicinity region based on the result. To do.

According to this configuration, the power supply unit that generates the bias voltage, the capacitance measurement unit that measures the capacitance, and the calculation unit that calculates the charge amount (voltage) from the measurement result of the capacitance, Measure the capacitance between the diaphragm and the electrode while applying a bias voltage between the diaphragm and the electrode of the electrostatic actuator. The amount of charge between the diaphragm portion and the electrode can be obtained from the bias voltage when taking the value and digitized.

In this case, the calculation unit approximates the relationship between the bias voltage and the capacitance as a quadratic curve, and determines the diaphragm portion from the bias voltage when the capacitance takes a plurality of specific values in the minimum vicinity region. It is preferable to calculate the amount of charge between the electrode and the electrode. According to this, the charge amount between the diaphragm portion and the electrode can be quantified more accurately.

Furthermore, in this case, it is preferable to include an adjustment unit that adjusts the drive voltage of the electrostatic actuator to a value corresponding to the charge amount calculated and output by the calculation unit. If this charge amount measuring device is used,
An appropriate drive voltage can be set according to the measurement of the charge amount.

First, an ink jet printer which is a recording apparatus as a liquid droplet ejection apparatus equipped with an ink jet head according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing the structure of an inkjet printer. Specifically, the inkjet head 10
FIG. 6 is a schematic view seen from the scanning direction of a carriage on which is mounted.

As shown in FIG. 1, the ink jet printer 400 includes feed rollers 402 and 405 for transporting the recording paper 401, and the recording paper 401 disposed to face the feed rollers 402 and 405.
Press rollers 403 and 404, an inkjet head 10 as a droplet discharge head, an ink supply pipe 41, and an ink tank member 409.

The inkjet head 10 is fixed to the carriage 406 via the base member 43 so that the nozzle surface 44 is parallel to the printing surface of the recording paper 401 at a predetermined interval. An ink supply pipe 41 connected to the ink tank member 409 is joined to the glass surface 45.

A carriage 406 that moves the inkjet head 10 is supported by a carriage shaft 408 and includes a belt 407 that moves the carriage 406 in connection with a driving mechanism (not shown).

The ink jet printer 400 includes a face ink jet type ink jet head 10, and ink is supplied from an ink tank member 409 through an ink supply pipe 41 joined to a glass surface 45 of the ink jet head 10. That is, the ink supply direction K and the ink discharge direction L are configured to be the same direction. Therefore, when the inkjet head 10 is driven, the ink droplets 42 are ejected onto the recording paper 401 positioned in parallel with the nozzle surface 44, and printing is performed by scanning the carriage 406 and feeding the recording paper 401.

Next, the ink jet head of this embodiment and the manufacturing method thereof will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing the structure of the inkjet head. The ink jet head 10 includes an electrode 1 disposed opposite to the diaphragm 5 and the diaphragm 5 at a predetermined interval.
1 is provided by an electrostatic actuator 19 having an electromechanical transducer 18 having
The liquid (ink) filled in the discharge chamber 6 located facing the surface is pressurized to discharge droplets from the nozzle 4.

In addition, the manufacturing process of the ink jet head according to the present embodiment includes a measurement process for measuring the charge amount between the diaphragm portion 5 of the electrostatic actuator 19 and the electrode 11, and whether the measured charge amount shows an abnormal value. If the abnormal value is indicated, a determination step of eliminating the electrostatic actuator 19 as defective, and, for a non-defective product, an adjustment step of adjusting the drive voltage of the electrostatic actuator 19 to a value corresponding to the measured charge amount And.

The ink jet head 10 has a three-layer structure including a glass substrate 1 having an electrode 11, a silicon substrate 2 having a diaphragm portion 5, and a nozzle plate 3 having nozzles 4.

The glass substrate 1 uses borosilicate glass with a thickness of 1 mm having the same thermal expansion coefficient as that of the silicon substrate 2, and a recess 1 for disposing the electrode 11 opposite to the diaphragm portion 5 at a predetermined interval.
5 is etched to a depth of approximately 0.3 μm. As an etching method, glass substrate 1
The surface other than the etched surface is masked with Cu—Au, and the glass substrate 1 is immersed in a mixed solution of ammonium fluoride and hydrogen peroxide at room temperature.

The electrode of the glass substrate 1 is made of an ITO (Indium Tin Oxide) film formed to a thickness of about 0.1 μm by sputtering or vapor deposition, and the electrode 11, the lead portion 12, and the terminal portion 13 are recessed by photolithography. 15 is formed in a predetermined shape on the bottom surface.

The silicon substrate 2 is a silicon single crystal substrate polished on both sides to a thickness of about 200 μm. First, a thermal oxidation process is performed to form SiO 2 oxide films having a thickness of about 0.1 μm on both sides of the substrate. This SiO 2 oxide film functions as an insulating layer 25 so that the diaphragm portion 5 and the electrode 11 are not electrically short-circuited.

The silicon substrate 2 is formed by a wet etching method immersed in an aqueous KOH solution, with a concave portion 22 serving as a discharge chamber 6 having the diaphragm portion 5 as a bottom surface and communicating with the nozzle 4, a concave portion 24 serving as a reservoir 8 serving as a common ink cavity, and a discharge A narrow groove 23 that forms an orifice 7 that connects the chamber 6 and the reservoir 8 is formed.

Further, the silicon substrate 2 is masked on the adhesive surfaces of the recesses 22 and 24 and the narrow grooves 23 and the nozzle plate 3 serving as the ink flow paths, and Pt (platinum) is deposited by vacuum evaporation or vacuum sputtering. A film-formed common electrode 26 is formed.

Then, by bonding the glass substrate 1 and the silicon substrate 2, an electrostatic actuator 19 having an electromechanical conversion element 18 in which the vibration plate portion 5 and the electrode 11 are arranged at a predetermined interval in the vibration chamber 9 is formed. ing. The vibration chamber 9 is sealed by sealing the gap between the glass substrate 1 and the silicon substrate 2 above the terminal portion 13. Furthermore, the glass substrate 1
And the silicon substrate 2 are formed with ink inlets 14 for supplying ink to the reservoir 8 which is a common ink cavity.

In this case, the distance between the electrode 11 of the glass substrate 1 and the diaphragm portion 5 of the silicon substrate 2 is about 0.2 μm.

The nozzle plate 3 is a silicon thin plate similar to the silicon substrate 2. The nozzle plate 3 is formed with a nozzle 4 for ejecting ink and another concave portion 17 constituting the orifice 7.

By further joining the nozzle plate 3 to the joined glass substrate 1 and silicon substrate 2, ink comprising a reservoir 8 connected to the ink intake 14 and a discharge chamber 6 connected to the reservoir 8 via the orifice 7. A flow path is formed.

FIG. 2 shows a schematic cross section of one electrostatic actuator 19 of the inkjet head 10 and an ink flow path corresponding to the electrostatic actuator 19. The inkjet head 10 having such a three-layer structure is shown in FIG.
Includes a liquid droplet discharge section in which a plurality of ink flow paths including a plurality of electrostatic actuators 19 and discharge chambers 6 and a plurality of nozzles 4 communicating with the discharge chamber 6 are formed.

The manufacturing method of the inkjet head 10 includes a wafer-shaped glass substrate 1 on which electrodes 11 corresponding to a plurality of inkjet heads 10 are formed, and a plurality of diaphragm portions 5.
And a method for forming a wafer-like laminate W by joining a wafer-like silicon substrate 2 on which ink flow paths are formed and a wafer-like nozzle plate 3 on which a plurality of nozzles 4 are formed at predetermined positions. It is. Then, the inkjet head 10 formed in a plurality of sections on the wafer-like laminate W is cut and taken out by a cutting method such as dicing.

Although not shown in the drawings, the liquid droplet ejection portion of the inkjet head 10 of the present embodiment is provided with one dummy electrostatic actuator for specifying the amount of charge between the diaphragm 5 of the electrostatic actuator 19 and the electrode 11. It has been. Needless to say, this dummy electrostatic actuator has the same structure and shape as the electrostatic actuator 19.

For the method and measuring device to measure the charge amount using this dummy electrostatic actuator,
It will be described later.

The ink jet head 10 includes an electrode 11 disposed to face the diaphragm 5 at a predetermined interval.
And a common electrode 2 provided on the silicon substrate 2.
6, an FPC (flexible circuit board) on which a driver IC 50 for driving the electrostatic actuator 19 is mounted is connected, a signal is input from the outside, and a voltage is applied.

The inkjet head 10 is driven by a common electrode 2 that defines the potential of the diaphragm 5.
6 is set to GND, and a positive (+) driving voltage pulse is applied to the electrode 11 with a predetermined pulse width and the number of pulses to displace the diaphragm portion 5 to fill the discharge chamber 6 having the diaphragm portion 5 as a bottom surface. Ink droplets are ejected from the nozzle 4 by pressurizing the ink.

Further, when the ink jet head 10 is used by being mounted on the ink jet printer 400 described above, a drive voltage pulse is used in order to reduce the charge generated between the diaphragm portion 5 and the electrode 11 due to the driving of the ink jet head 10. The negative (−) drive voltage pulse is applied to the electrode 11 at a rate of once every 400 times. In this case, the negative drive voltage pulse may be a drive voltage pulse having the same potential width and having a polarity opposite to that of the positive drive voltage pulse.

The ink used is prepared by dissolving or dispersing a surfactant such as ethylene glycol and a dye or pigment in a main solvent such as water or alcohol. Furthermore, if a heater or the like is attached to the inkjet head 10, hot melt type ink can also be used. The ink jet head 10 of the present embodiment is a face ink jet system, but may be an edge ink jet system in which the nozzles 4 for ejecting ink are opened on the end surface of the silicon substrate 2 or the nozzle plate 3.

Next, the charge amount measuring apparatus of this embodiment will be described with reference to FIG. FIG. 3 is a schematic diagram showing the configuration of the charge amount measuring apparatus.

The charge amount measuring apparatus 100 includes a power supply unit 101 for applying a predetermined bias voltage between the vibration plate unit 5 and the electrode 11 of the measurement workpiece 105, and the vibration plate unit 5 to which a bias voltage (V) is applied. An LCR meter 102 as a capacitance measuring unit that measures the capacitance (C) between the electrode 11 and the electrode 11.
A personal computer (PC) 1 connected to the power supply unit 101 and the LCR meter 102
03.

The PC 103 approximates the relationship between the bias voltage and the capacitance as a quadratic curve based on the capacitance measurement result of the LCR meter 102, and the diaphragm unit 5, the electrode 11, and the like from the bias voltage that minimizes the capacitance. And a control processing unit that connects to and controls the power supply unit 101 and the LCR meter 102 are executed. The calculation unit is constructed by the PC 103 that executes the calculation process, and the control unit is constructed by the PC 103 that executes the control process.

In addition, a monitor 104 is connected to the PC 103, and the monitor 104 can display an operation state of the measurement system and measurement data or a graph based on the measurement data.

The power supply unit 101 is connected to the LCR meter 102 and outputs DC bias voltages having different polarities over a predetermined range. Further, it has an interface (IEEE 488) for receiving a command from the PC 103 and outputting a bias voltage. The power supply unit 101 may be any type of stabilized power supply as long as it has an interface that can be controlled from the PC 103.

The measurement terminal of the LCR meter 102 is an inkjet head 1 that is a measurement workpiece 105.
Zero dummy electrostatic actuators are connected by a four-terminal method. In this case, the measurement workpiece 10
5 may be the original electrostatic actuator 19.

The charge amount measuring apparatus 100 measures the electrostatic capacitance between the diaphragm unit 5 and the electrode 11 with the LCR meter 102 while applying a bias voltage between the diaphragm unit 5 and the electrode 11 of the measurement work 105. , Stored in the PC 103. The PC 103 outputs a calculation result as a charge amount between the diaphragm unit 5 and the electrode 11 from a bias voltage that minimizes the capacitance by a calculation program stored based on the stored data.

Next, a method for measuring the charge amount of the electrostatic actuator according to the present embodiment will be described with reference to FIGS. This method of measuring the amount of charge uses a bias voltage (V) between the diaphragm 5 and the electrode 11.
Measuring step of measuring the capacitance (C) between the diaphragm portion 5 and the electrode 11 while applying
This is constituted by a calculation step of obtaining a charge amount charged between the diaphragm portion and the electrode from a bias voltage at which the electrostatic capacitance is minimized.

More specifically, in the measurement step, a plurality of capacitances between the diaphragm portion 5 and the electrode 11 with respect to the bias voltage are measured, and in the calculation step, the least square method is used based on the capacitance measured at the plurality of points. In this method, the relationship between the bias voltage and the capacitance is approximated as a quadratic curve, and the charge amount is obtained from the bias voltage that minimizes the quadratic curve.

In this case, in the calculation step, when the relationship between the bias voltage and the capacitance is approximated as a quadratic curve, the rising portion and the falling portion where the diaphragm portion 5 is suddenly displaced by applying the bias voltage are applied. The approximation method is used except for the measured values. In this case, the data obtained sequentially in the measurement process are compared, and the measurement value of the portion where the capacitance change rate between the previous and subsequent data is ± 50% or more is excluded.

FIG. 4 is a graph showing the bias voltage applied during measurement. As described above, the ink-jet head 10 is driven by drive voltage pulses having different positive and negative (reverse) polarities.
In this case, the range of the drive voltage is positive side + 40V and negative (reverse) side -30V. Therefore, the bias voltage applied at the time of measurement is obtained in order to obtain the charge amount charged by the drive voltage range. In the same bias voltage range, a DC voltage is applied by increasing / decreasing with time. Although not shown in detail in FIG. 4, the application of the bias voltage is performed by stepping the voltage.
It is increased or decreased stepwise in 2 seconds. The method for applying the bias voltage will be described in the subsequent measurement process.

FIG. 5 is a measurement flowchart showing the measurement process. Measurement is cnt (count) = 1
To 6 and a positive electric field measurement routine for applying a positive electric field three times, and a reverse electric field measurement routine for applying a reverse electric field once to cnt (count) = 7 to 8.

First, in step S1, the inkjet head 10 is connected to the LCR meter 102 of the charge amount measuring apparatus 100, and the system is initialized. The bias voltage at this time is 0V.

  Next, in step S2, the measurement is started by setting the measurement count to cnt = 1.

  In step S3, the capacitance when the bias voltage is 0 V is measured, and the data is stored.

In steps S4 to S5, the bias voltage applied between the diaphragm portion 5 and the electrode 11 is 2v.
In step / 2 sec, the capacitance between the diaphragm portion 5 and the electrode 11 is measured, and the data is stored.

In step S6, it is determined whether or not the bias voltage has reached the upper limit (40V). If not, the process returns to step S4 and repeats the measurement. If the upper limit (40V) is reached, the process proceeds to the next step S7.

In step S7, the current cnt is incremented by one to set cnt = 2, and the process proceeds to the next step S8.

In steps S8 to S9, the bias voltage is decreased at -2v step / 2sec, and c
As in the case of nt = 1, the capacitance is measured and the data is stored. The first positive electric field application charges between the diaphragm portion 5 and the electrode 11.

In step S10, it is determined whether or not the bias voltage has reached 0V. If not, the process returns to step S8 and repeats the measurement. If 0V is reached, the process proceeds to the next step S11.

In step S11, the current cnt is incremented by 1 and cnt = 3, and the process proceeds to the next step S12.

In step S12, it is determined that steps S4 to S11 are repeated until cnt reaches 7, and the bias voltage 0V to 40V is further increased and decreased twice, and the capacitance during this time is measured. When cnt becomes 7, the process proceeds to the next steps S13 to S14.

In steps S13 to S14, the bias voltage is lowered at -2v step / 2 sec, the capacitance is measured, and the data is stored.

In step S15, it is determined whether or not the bias voltage has reached the lower limit (−30V).
If not, the process returns to step S13 to repeat the measurement. If the lower limit (−30V) is reached, the process proceeds to the next step S16.

In step S16, the current cnt is incremented by 1 and cnt = 8, and the next steps S17 to S17 are performed.
Proceed to 18.

In steps S17 to S18, the bias voltage is increased at 2v steps / 2 seconds, the capacitance is measured, and the data is stored.

In step S19, it is determined whether or not the bias voltage has reached 0V. If not, the process returns to step S17 to repeat the measurement. The measurement ends when 0V is reached. cn
The reverse electric field measurement routine from 0V to −30V is completed once by t = 7-8.

By the above measurement of cnt = 1 to 8, the capacitance data between the diaphragm portion 5 and the electrode 11 is stored in the range of the bias voltage of 40V to −30V.

FIG. 7 shows an electrostatic actuator 1 of an inkjet head that is actually used by using the above measurement method.
It is a graph which shows the result of having measured the CV characteristic of 9. FIG. When a bias voltage is applied between the diaphragm portion 5 of the electrostatic actuator 19 and the electrode 11 as shown in FIG.
It can be seen that the distance between the diaphragm portion 5 and the electrode 11 is narrowed and the CV characteristic is changed by being drawn to 1.

The electrostatic actuator 19 constituting the ink jet head 10 includes the vibration plate portion 5 and the electrode 1.
An insulating layer 25 made of a SiO2 oxide film is interposed between the insulating layer 25 and the insulating layer 25 functions as a dielectric when a voltage is applied between the vibration plate portion 5 and the electrode 11, so that the insulating layer 25 is charged. Electrification occurs.

Therefore, for example, the relationship between the electrostatic capacity and the bias voltage when there is no charging and the relationship between the electrostatic capacity and the bias voltage when there is charging are graphs of CV characteristics shown in FIG.

8 shows a bias voltage of 40 V to −3 between the diaphragm portion 5 and the electrode 11 as shown in FIG.
It is the graph which compared the CV characteristic when it applied in the range of 0V so that it may be intelligible with the case where there is no charge temporarily. As shown in FIG. 8, the CV characteristic is shifted to the positive side when the insulating layer 25 is charged to the positive side. In other words, this shift amount Vc can be treated as a charge amount between the diaphragm portion 5 and the electrode 11.

FIG. 9 is an enlarged graph around the bias voltage of 0 V in the CV characteristic of FIG. As shown in FIG. 9, the curve indicating the CV characteristic is a gentle curve near the bias voltage of 0V. Therefore, when there is a charge, this gentle curve portion is approximated as a quadratic curve, and if a minimum bias voltage is obtained, it can be converted into a numerical value as a charge amount.

Next, a calculation process for digitizing the shift amount Vc will be described with reference to FIG.
FIG. 6 is a flowchart showing the calculation program of the calculation process.

The least square method is used as a method of approximating as a quadratic curve. If Y is an electrostatic capacity and X is a bias voltage, an approximate expression of Y = aX2 + bX + c is applied. a, b, and c are coefficients.

In step S21 of FIG. 6, the bias voltage of the positive electric field measurement routine extracted by cnt = 1 by the charge amount measuring method described above and the value of the capacitance with respect to the bias voltage are taken in as data.

In step S22, four bias voltages in the vicinity of the minimum capacitance of the captured data are extracted. In this case, as described above, the data of the portion where the diaphragm portion 5 is rapidly displaced by the application of the bias voltage is excluded and not adopted.

In step S23, calculation is performed by applying the extracted bias voltages of the four points to the above approximate expression to calculate coefficients a, b, and c.

In step S24, it is determined whether or not the coefficient a is a positive value. If the coefficient a is 0 (zero) or a negative value, an error display is output. If the coefficient a is positive, it is determined that the approximation has been correctly performed, and the process proceeds to the next step S25.

In step S25, the bias voltage value X that is minimized by differentiating the approximated quadratic equation.
t = −b / (2 × a) is calculated and output as a charge amount of cnt = 1 which is the current count.

In the next step S26, it is determined whether or not cnt has been calculated up to 8. If cnt is not 8, the process returns to step S21 to fetch the next cnt data and repeat the calculation. cnt =
When the calculation is completed up to 8, the process proceeds to the next step S27.

In step S27, the charge amount of cnt = 1 when the positive electric field is applied for the first time is displayed on the monitor 104.

In step S28, the charge amount of cnt = 2 to 6 when a positive electric field is applied is displayed on the monitor 104.

In step S29, the charge amount of cnt = 7 to 8 when a negative (reverse) electric field is applied is displayed on the monitor 104.

In step S30, the average value of the bias voltage value Xt obtained by the measurement of cnt = 2 to 6 is output as the charge amount. At the same time, the average value range is also calculated. If statistical processing is performed using the average value of the charge amount and the range of the average value, fluctuations in the manufacturing process of the inkjet head 10 including the electrostatic actuator 19 can be grasped.

In step S31, it is determined whether or not the charge amount value and range obtained in step S30 are within a predetermined standard value. If it is within the standard value, the calculation process is terminated. If it is outside the standard value, the process proceeds to step S32, and after outputting a defective product exclusion signal, the calculation process is terminated.

Steps S31 and S32 determine whether or not the calculated charge amount indicates an abnormal value.
In the case where an abnormal value is indicated, this is a determination step of eliminating the electrostatic actuator 19 as defective.
When the charge amount shows an abnormal value, there may be an abnormal cause such as the vibration chamber 9 formed by the diaphragm portion 5 and the electrode 11 not being securely sealed. Therefore, it is possible to detect an abnormality of the inkjet head 10 using this charge amount measurement method.

In the electrostatic actuator charge amount measuring method of the present embodiment, the inkjet head 10 having the electrostatic actuator 19 is driven mainly by applying a positive drive voltage pulse. Therefore, as shown in the measurement flowchart of FIG. 5, a positive electric field measurement routine of cnt = 2 to 6 excluding the initial positive electric field measurement routine that causes charging between the diaphragm portion 5 of cnt = 1 and the electrode 11. Based on the data obtained from the above, the average value of the bias voltage that minimizes the capacitance is used as the charge amount.

The measurement flowchart shown in FIG. 5 is not limited to this setting, and the measurement method can be set in consideration of the driving method of the inkjet head 10. For example, positive and negative (reverse)
The inkjet head 10 has an application pattern in which drive voltage pulses having different polarities are combined.
In the measurement routine, it is preferable that the measurement routine applies bias voltages having different positive and negative (reverse) polarities in accordance with the application pattern. Further, it is preferable to set the voltage range to which the bias voltage is applied in accordance with the drive voltage range.

The flowchart showing the calculation program of the calculation process shown in FIG. 6 is not limited to this method, and the selection of the measurement routine for the positive electric field or the reverse electric field to be taken in can be set as appropriate based on the setting of the measurement process. For example, in order to increase the accuracy of the required charge amount, the number of bias voltage data for approximating the quadratic curve is not limited to four, and may be increased.

Further, in the manufacturing process of the inkjet head 10, as shown in FIG. 2, a plurality of inkjet heads 10 are formed on the wafer-like laminate W in which the glass substrate 1, the silicon substrate 2, and the nozzle plate 3 are laminated. Then, the wafer-like laminate W is cut using a method such as dicing, and the inkjet head 10 is taken out. The taken out inkjet head 1
After the drive circuit having the driver IC 50 is mounted on 0, the charge amount of the electrostatic actuator 19 is measured by using the above-described electrostatic actuator charge amount measurement method. And the adjustment process which adjusts a drive voltage to the value according to this charge amount is provided so that the inkjet head 10 may be in an optimal drive state.

The adjustment step uses a method of ranking the obtained charge amount for each adjustable voltage range and setting the output voltage level of the drive circuit according to the voltage rank. The relationship between the driving voltage V applied between the diaphragm portion 5 of the electrostatic actuator 19 having the electromechanical conversion element 18 and the electrode 11 and the pressure P generated in the diaphragm portion 5 is as follows when there is no charge. Derived by mathematical formula.

P = 1/2 × ε × (V / d) 2, ε is a dielectric constant between the diaphragm portion 5 and the electrode 11, and d is an interval (gap) between the diaphragm portion 5 and the electrode 11. Charge amount V between diaphragm 5 and electrode 11
When c is provided, the gap d between the diaphragm portion 5 and the electrode 11 is narrowed by charging. Therefore, in order to make the pressure P constant, it is necessary to reduce the actual drive voltage Vd accordingly.

The inkjet head 10 including the electrostatic actuator 19 with the drive voltage adjusted in this way can obtain stable ejection characteristics by being driven under appropriate drive conditions.

The effects in the above embodiment are as follows.
(1) The method for measuring the charge amount of the electrostatic actuator according to the present embodiment is such that a bias voltage (V) is applied between the diaphragm 5 and the electrode 11 while a static voltage between the diaphragm 5 and the electrode 11 is applied. Electric capacity (C)
And the average value of the bias voltage Xt that minimizes the electrostatic capacitance is used as the charge amount, so that the charge amount between the diaphragm portion 5 and the electrode 11 can be quantified.
(2) The charge amount measuring apparatus 100 approximates the relationship between the bias voltage (V) and the capacitance (C) as a quadratic curve based on the measurement result of the LCR meter 102 as the capacitance measuring unit, and the capacitance PC 10 provided with a calculation unit that calculates the average value of the bias voltage Xt that minimizes the charge amount
3, the amount of charge between the diaphragm 5 and the electrode 11 can be accurately quantified.
(3) The droplet discharge portion of the inkjet head 10 has the same structure as the electrostatic actuator 19,
Since the dummy electrostatic actuator having the same shape is provided, if the charge amount between the diaphragm portion 5 and the electrode 11 of this dummy electrostatic actuator is measured, it can be handled as the original charge amount of the electrostatic actuator 19. it can. Moreover, in order to measure without using the electrostatic actuator 19,
The risk that the electrostatic actuator 19 deteriorates due to application of a bias voltage during measurement can be avoided.
(4) When the arithmetic processing unit of the PC 103 of the charge amount measuring apparatus 100 approximates the relationship between the bias voltage (V) and the capacitance (C) as a quadratic curve, the diaphragm unit is applied by applying the bias voltage. Since the approximation method is used except for the measured values at the rising and falling portions where 5 is abruptly displaced, the charge amount can be digitized by accurately approximating this quadratic curve.
(5) Since the adjustment process of adjusting the drive voltage of the electrostatic actuator 19 based on the result of the charge amount measurement of the electrostatic actuator 19 in the manufacturing process of the inkjet head 10 is provided, the adjusted electrostatic actuator Inkjet head 10 with 19 is
Stable ejection characteristics can be obtained by being driven under appropriate driving conditions.
(6) When the charge amount measurement of the inkjet head 10 is performed using the charge amount measuring apparatus 100, the abnormality of the electrostatic actuator 19 constituting the inkjet head 10 can be detected from the obtained charge amount result.
(7) Since the inkjet printer 400 is equipped with the inkjet head 10 having stable ejection characteristics, stable ejection quality can be realized.

The modification of the said embodiment is as follows.
(Modification 1) The specific plural values in the minimum neighborhood region are not limited to the minimum value. For example, in the quadratic curve of the CV characteristic, an average value obtained by dividing the sum of bias voltages at two points where the capacitances have the same value by 2 may be employed. In this case, an approximate value of the charge amount can be obtained although it does not necessarily match the minimum value.
(Modification 2) The measurement workpiece 105 may be a dummy electromechanical conversion element provided in at least one region other than the inkjet head 10 formation region of the wafer-like laminate W in which the inkjet head 10 is formed in a plurality of sections. . If the charge amount is measured using this dummy electromechanical transducer, the charge amount of the original electrostatic actuator 19 can be replaced. Further, the inkjet head 10 can be reduced in size as compared with the case where the dummy electrostatic actuator is provided in the inkjet head 10. Thereby, the use area efficiency of the wafer-like laminated body W in which the inkjet head 10 is formed in a plurality of sections can be improved.
(Modification 3) The charge amount measurement step of the electrostatic actuator 19 and the drive voltage adjustment step may be a series of steps. Further, the charge amount measuring apparatus 100 may be added with a function for ranking the voltage from the output charge amount, a function for adjusting the drive voltage, and the like.
(Modification 4) In the inkjet head 10 of the present embodiment, the liquid to be filled is not limited to ink. For example, the functional liquid that is discharged when a color filter or an organic EL display device is manufactured by an inkjet method may be filled in the inkjet head 10 as a liquid.

The technical idea grasped from the above-described embodiments and modifications is as follows.
(1) In a method of manufacturing an electrostatic actuator having an electromechanical transducer having a diaphragm portion and an electrode disposed opposite to the diaphragm portion at a predetermined interval, a charge amount of the electrostatic actuator is measured. A method for manufacturing an electrostatic actuator, comprising: a measuring step for determining, and a determining step for determining whether or not the amount of charge in the previous period obtained in the measuring step is an abnormal value.
(2) In a method for manufacturing an electrostatic actuator having an electromechanical transducer having an oscillating plate and an electrode disposed opposite to the oscillating plate at a predetermined interval, a charge amount of the electrostatic actuator is measured. A measuring step, and a step of ranking the charge amount obtained in the measuring step as a voltage rank having a predetermined voltage width, and adjusting a driving voltage of the electrostatic actuator for each voltage rank. Manufacturing method of electrostatic actuator.
(3) A discharge chamber positioned facing the vibration plate portion by an electrostatic actuator having an electromechanical transducer having a vibration plate portion and an electrode disposed opposite to the vibration plate portion at a predetermined interval. In a method of manufacturing a droplet discharge head that pressurizes a liquid filled in a nozzle and discharges droplets from a nozzle, a measurement step for measuring the charge amount of the electrostatic actuator, and the charge amount obtained in the measurement step include A determination step for determining whether or not the value is an abnormal value and the charge amount obtained in the measurement step are ranked as a voltage rank having a predetermined voltage width, and the driving voltage of the electrostatic actuator is adjusted for each voltage rank. A method for manufacturing a droplet discharge head comprising an adjusting step.

1 is a schematic diagram showing the structure of an inkjet printer according to an embodiment. FIG. 2 is a schematic cross-sectional view showing the structure of an inkjet head. Schematic which shows the structure of a charge amount measuring apparatus. The graph which shows the bias voltage applied between a diaphragm part and an electrode. The measurement flowchart which shows a measurement process. The flowchart which shows the calculation program of a calculation process. The graph which shows the result of having measured the CV characteristic of the electrostatic actuator. The graph which compared the CV characteristic with the case where there is no electrification and the case where it exists. The graph which expanded the bias voltage 0V vicinity of the CV characteristic of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Glass substrate as 1st board | substrate, 2 ... Silicon substrate as 2nd board | substrate, 3 ... Nozzle plate as 3rd board | substrate, 4 ... Nozzle, 5 ... Vibration plate part, 6 ... Discharge chamber, 10 ... Inkjet head as a droplet discharge head, 11 ... electrode, 18 ... electromechanical transducer, 19 ... electrostatic actuator, 100 ... charge amount measuring device, 101 ... power supply unit, 102 ... LCR meter as capacitance measuring unit, 103 ... PC (personal computer) as a calculation unit and a control unit, 400... Inkjet printer as a droplet discharge device.

Claims (13)

In the method for measuring the amount of charge of an electrostatic actuator comprising an electromechanical transducer having a diaphragm part and an electrode disposed opposite to the diaphragm part at a predetermined interval,
A measurement step of measuring a capacitance between the diaphragm portion and the electrode while applying a bias voltage between the diaphragm portion and the electrode;
And a calculation step of obtaining a charge amount charged between the diaphragm portion and the electrode from the bias voltage when the capacitance takes a plurality of specific values in a minimum vicinity region. A method for measuring the charge amount of an electrostatic actuator. In the measurement step, a plurality of points of capacitance between the diaphragm portion and the electrode with respect to the bias voltage are measured,
In the calculation step, a relationship between the bias voltage and the capacitance is approximated as a quadratic curve by a least square method based on the capacitance measured at the plurality of points, and the quadratic curve is a minimum neighborhood region. 2. The method for measuring a charge amount of an electrostatic actuator according to claim 1, wherein the charge amount is obtained from the bias voltage when taking a plurality of specific values.   In the calculating step, when approximating the relationship between the bias voltage and the capacitance as the quadratic curve, a rising portion and a falling portion where the diaphragm portion is suddenly displaced by applying the bias voltage are applied. The method for measuring the charge amount of the electrostatic actuator according to claim 2, wherein the charge amount is approximated except for a measurement value. In a method of manufacturing an electrostatic actuator having an electromechanical transducer having a diaphragm part and an electrode disposed opposite to the diaphragm part with a predetermined interval,
A measurement step of measuring a charge amount charged between the diaphragm portion and the electrode using the method for measuring the charge amount of the electrostatic actuator according to any one of claims 1 to 3,
An adjustment step of adjusting a drive voltage of the electrostatic actuator to a value corresponding to the measured charge amount.   5. The method according to claim 4, further comprising a determination step of determining whether or not the measured charge amount indicates an abnormal value, and determining that the measured value indicates an abnormal value, and rejecting the electrostatic actuator as a failure. A method for producing the electrostatic actuator according to 1. The discharge chamber located facing the diaphragm is filled by an electrostatic actuator having an electromechanical transducer having a diaphragm and an electrode disposed opposite to the diaphragm at a predetermined interval. In a method of manufacturing a droplet discharge head that pressurizes the liquid and discharges a droplet from a nozzle,
The droplet discharge head has a droplet discharge portion in which a plurality of compartments are formed with the electrostatic actuator, a liquid flow path including the discharge chamber, and a nozzle communicating with the discharge chamber,
The measurement which measures the charge amount of one of the electrostatic actuators formed in the plurality of sections of the droplet discharge section using the method for measuring the charge amount of an electrostatic actuator according to any one of claims 1 to 3. A method for manufacturing a droplet discharge head, comprising: a step; and an adjustment step according to claim 4 or a determination step according to claim 5.   The droplet discharge unit includes at least one dummy electrostatic actuator, and in the measurement step, the charge amount between the diaphragm portion and the electrode of the dummy electrostatic actuator is measured. A method for manufacturing a droplet discharge head according to claim 6. The discharge chamber located facing the diaphragm is filled by an electrostatic actuator having an electromechanical transducer having a diaphragm and an electrode disposed opposite to the diaphragm at a predetermined interval. In a method of manufacturing a droplet discharge head that pressurizes the liquid and discharges a droplet from a nozzle,
The droplet discharge is applied to the wafer-like laminate obtained by joining the wafer-like first substrate on which the electrode is formed and the wafer-like second substrate on which the diaphragm is formed. Forming the electrostatic actuator for a plurality of heads, and forming at least one dummy electrostatic actuator in a region other than the formation region of the droplet discharge head;
A cutting step of cutting out the plurality of droplet discharge heads from the wafer-shaped laminate;
4. The electrostatic actuator charge amount measuring method according to claim 1, wherein at least one charge amount of the dummy electrostatic actuator is applied to the droplet discharge head obtained by the cutting step. 5. And a measuring step for measuring using, and an adjusting step for adjusting the driving voltage according to claim 4 or a determining step for determining whether or not the charge amount according to claim 5 shows an abnormal value. A method for manufacturing a droplet discharge head.   An electrostatic actuator manufactured using the method for manufacturing an electrostatic actuator according to claim 4.   A droplet discharge head manufactured using the method for manufacturing a droplet discharge head according to claim 6. In the electrostatic charge measuring device of an electrostatic actuator comprising an electromechanical transducer having a diaphragm part and an electrode disposed opposite to the diaphragm part at a predetermined interval,
A power supply for applying a predetermined bias voltage between the diaphragm and the electrode;
A capacitance measuring unit for measuring a capacitance between the diaphragm unit to which the bias voltage is applied and the electrode;
Based on the capacitance measurement result of the capacitance measurement unit, the charge amount between the diaphragm unit and the electrode from the bias voltage when the capacitance takes a plurality of specific values in the minimum vicinity region A charge amount measuring device for an electrostatic actuator, comprising: The arithmetic unit approximates the relationship between the bias voltage and the capacitance as a quadratic curve, and the vibration is generated from the bias voltage when the capacitance takes a plurality of specific values within a minimum vicinity region. 12. The electrostatic charge measuring device for an electrostatic actuator according to claim 11, wherein a charge amount between the plate portion and the electrode is calculated.   The static unit according to claim 11 or 12, further comprising an adjusting unit that adjusts a driving voltage of the electrostatic actuator to a value corresponding to the charge amount calculated and output by the calculating unit. Electric actuator charge amount measuring device.

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