JP4227735B2 - Actuator, inkjet head, inkjet recording apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an actuator, an inkjet head , and an inkjet recording apparatus , and more specifically, an actuator that displaces a diaphragm using electrostatic attraction and an inkjet head that discharges ink droplets by compressing a liquid chamber on the diaphragm. The present invention also relates to an ink jet recording apparatus .
[0002]
[Prior art]
Inkjet recording devices do not require processes such as development and fixing, and can perform non-contact recording, so the recording noise is extremely low, the degree of freedom of ink is high, and inexpensive plain paper is used. Since it has many advantages, it can be used as an image recording apparatus such as a printer, a facsimile machine, and a copying machine.
[0003]
An ink jet head used in such an ink jet recording apparatus is also referred to as a nozzle hole for discharging ink droplets and a discharge chamber (pressure chamber, pressurized liquid chamber, liquid chamber, ink flow path, etc.) through which the nozzle hole communicates. And an energy generating means (actuator) for generating energy for pressurizing the ink in the discharge chamber, and driving the actuator to pressurize the ink in the discharge chamber and discharge ink droplets from the nozzle holes. An ink-on-demand system that ejects ink droplets only when recording is necessary is the mainstream.
[0004]
Actuators and inkjet heads are roughly classified into several methods depending on the method for generating ink droplets (recording liquid) and the control method for controlling the flight direction. Ink jet heads using electric actuators are often used (see, for example, JP-A-4-52214 and JP-A-3-293141).
[0005]
This electrostatic actuator generally forms a liquid chamber and a diaphragm that forms one wall surface of the liquid chamber by etching on a first substrate (vibrating plate substrate) made of a silicon substrate. An electrostatic actuator is configured by disposing a second substrate (electrode substrate) on which an electrode is formed on the lower side and making the electrode face each other with a predetermined gap between the diaphragm and the diaphragm of the electrostatic actuator. By applying a voltage between the electrodes, the diaphragm is deflected by an electrostatic force to change the internal volume of the liquid chamber, and ink droplets are ejected from nozzles communicating with the liquid chamber.
[0006]
The driving method of the actuator of the electrostatic ink jet head is classified into two types according to the limit of displacement when the diaphragm is pulled by electrostatic force, and is disclosed in JP-A-7-10470 and the like. In addition, a method of displacing the diaphragm until it contacts (abuts) the opposing electrode (opposite electrode) (referred to as a “contact driving” system) and a displacement of the diaphragm are limited to a range not contacting the counter electrode. System (referred to as “non-contact drive” system).
[0007]
Compared to the non-contact driving method, the contact driving method increases the displacement of the diaphragm about three times if the distance between the diaphragm and the electrode facing it is the same. Even if it is made small, an injection amount equivalent to non-contact driving can be obtained, and as a result, there is an advantage that driving can be performed at a lower voltage. In addition, the contact drive method is not appropriate because the amount of displacement of the diaphragm is regulated by the gap size between the diaphragm and the electrode facing the diaphragm, and the droplet ejection amount is easily kept constant. Excellent for contact drive.
[0008]
[Problems to be solved by the invention]
However, in the electrostatic actuator, gas exists between the diaphragm and the electrode facing the diaphragm, and when the diaphragm approaches the electrode, the gas is compressed, and thus a repulsive force is generated in the diaphragm. This is said to be the air damper effect, and is conspicuous when the diaphragm is moved at a high speed so that the space between the diaphragm and the electrode facing it is sealed or there is no time for gas to escape even if it is not sealed. Observed at. In particular, when the actuator is sealed, the volume of the space between the diaphragm and the electrode facing it changes due to changes in atmospheric pressure or changes in temperature of the actuator, and the air damper effect changes significantly, resulting in displacement of the actuator. This causes the amount to vary.
[0009]
In addition, this air damper effect is particularly noticeable in the case of the contact drive method because the diaphragm compresses air more than the non-contact drive method, and increases the voltage required for driving. It is the main cause.
[0010]
Therefore, conventionally, the electrode or its periphery is provided with a recess, and this recess is used as an air escape place, or the space between the diaphragm and the electrode facing the diaphragm is in a state of opening to the atmosphere that is not sufficiently sealed. Or drive at speed.
[0011]
However, with the former method, the absolute value of the air damper effect can be reduced to some extent, but it is not sufficient, and the volume of the space between the diaphragm and the electrode facing it increases, so the temperature and atmospheric pressure of the actuator There is a problem that the variation in the displacement amount of the actuator due to the change of the actuator becomes further larger. In addition, the latter method not only has a fundamental problem that the actuator is slow, but also dust and other foreign matters enter the actuator, and the surface of the electrode and the diaphragm is deteriorated by moisture, oxygen, etc. in the atmosphere. As a result, the reliability of the actuator is reduced. As a result, neither of these methods is sufficient as a solution.
[0012]
The present invention has been made in view of the above problems, and an object of the present invention is to reduce the air damper effect with respect to the displacement of the diaphragm so that it can be driven with a low driving voltage.
[0021]
[Means for Solving the Problems]
To solve the above problems, an actuator according to the present invention,
The diaphragm and the electrode are arranged opposite to each other with a predetermined gap forming a gas chamber, and the diaphragm is displaced in the electrode direction by electrostatic force by applying a voltage between the diaphragm and the electrode. In the actuator where the diaphragm is restored by stopping the application of the voltage ,
The space between the gas chamber and the outside is sealed with a sealing member,
The sealing member is formed with a communication hole that communicates between the gas chamber and the outside.
The communication hole is provided with an opening / closing valve that opens when gas flows out from the gas chamber to the outside, and closes when gas flows from the outside into the gas chamber,
The gas chamber is depressurized by repeatedly displacing the diaphragm.
The configuration.
[0022]
The ink jet head according to the present invention includes the actuator according to the present invention.
[0023]
An ink jet recording apparatus according to the present invention includes the ink jet head according to the present invention.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. The embodiments described below are preferred embodiments of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. As long as there is no description which limits, it is not restricted to these aspects.
[0040]
1 and 2 are views showing a first embodiment of an actuator and an inkjet head according to the present invention. FIG. 1 is an inkjet head to which the first embodiment of the actuator and the inkjet head according to the present invention is applied. FIG.
[0041]
In FIG. 1, an inkjet head 1 includes a diaphragm substrate 3, a liquid chamber substrate 4, and a nozzle plate 5 sequentially stacked on an electrode substrate 2, and the vibration plate substrate 3, the liquid chamber substrate 4, and the nozzle plate 5 A plurality of pressurized liquid chambers 6 are defined in the front and back direction on the paper surface of FIG. The nozzle plate 5 is formed with a plurality of nozzles 7 communicating with the pressurized liquid chambers 6.
[0042]
The diaphragm substrate 3 is formed with a recess 8 that becomes the pressurized liquid chamber 6, and the bottom surface of the recess 8 is formed as a diaphragm 9. Although not shown, the diaphragm substrate 3 includes a common ink chamber that supplies ink to each pressurized liquid chamber 6, a recess that forms a fluid resistance portion that communicates the common ink chamber and the pressurized liquid chamber 6, and the like. A groove or the like is formed. The diaphragm substrate 3 is formed by etching a metal substrate such as a SUS substrate, a silicon substrate, or the like to form a desired fine liquid chamber pattern, and the pressurizing liquid chamber 6, the concave portion, the groove, and the like are formed.
[0043]
The liquid chamber substrate 4 is formed with a hole 10 that forms the pressurized liquid chamber 6 together with the concave portion 8 of the vibration plate substrate 3, and the nozzle plate 5 is joined to the upper portion of the liquid chamber substrate 4 to form the pressurized liquid chamber. (Liquid chamber) 6 is defined.
[0044]
The electrode substrate 2 and the recess 11 are formed, and the individual electrode 12 serving as the second electrode is provided at a position facing the diaphragm 9 on the bottom surface of the recess 11 with a predetermined (for example, 0.2 μm) gap. And is sealed with a sealing member 14 in a state where a gas chamber 13 is defined in a gap portion between the individual electrode 12 and the diaphragm 9. The individual electrode 12 and the diaphragm 9 constitute an actuator unit (actuator) 15 that displaces the diaphragm 9 and changes the internal volume of the pressurized liquid chamber 6. The electrode substrate 2 is formed by etching a metal such as SUS, glass, Si or the like to form a recess 11, and electrode material such as Ni, Al, Ti, Pt, or Cu is formed in the recess 11 by sputtering, CVD, vapor deposition, or the like. The individual electrodes 12 are formed only in the recesses 11 by forming a photoresist with a desired thickness by a film formation technique, and then forming a photoresist and etching it. Further, an insulating layer 16 such as SiO 2 is formed on the individual electrode 12 of the electrode substrate 2 in order to prevent the individual electrode 12 from being damaged by a short circuit or discharge.
[0045]
The nozzle plate 5 is formed of a metal plate such as Ni or SUS, glass, resin, or the like, and is manufactured by a known method such as etching or an electroforming method of nickel. In the nozzle plate 5, the nozzles 7 are arranged in two rows in a zigzag pattern so that the nozzle density is high. Correspondingly, the vibrating plate substrate 3 and the liquid chamber substrate 2 have a pressurized liquid. The chamber 6 and the diaphragm 9 are formed on the electrode substrate 2 and the individual electrodes 12 are formed in two rows. Further, a water repellent film is formed on the nozzle surface (surface in the ejection direction) of the nozzle plate 5 by a known method such as a plating film or a water repellent coating to ensure water repellency with ink. Yes.
[0046]
The diaphragm substrate 3, the liquid chamber substrate 4, the electrode substrate 2 and the nozzle plate 5 are bonded by a direct bonding method such as an adhesive or anodic bonding, a eutectic bonding method, or the like.
[0047]
The ink jet head 1 is charged by applying a voltage between the diaphragm 9 and the individual electrode 12 to generate a coulomb by electric charge, and bends the diaphragm 9 until it contacts (contacts) the individual electrode 12. The volume of the pressurized liquid chamber 6 is expanded. From this state, the ink jet head 1 suddenly discharges the electric charge between the individual electrode 12 and the diaphragm 9, thereby returning the diaphragm 9 by its elastic restoring force, and the volume in the pressurized liquid chamber 6 is increased. The ink droplet is ejected from the nozzle 7 by the ink pressure generated in the pressurized liquid chamber 6 at this time. The inkjet head 1 again applies a voltage between the vibration plate 9 and the individual electrode 12 to displace the vibration plate 9 until it contacts the individual electrode 12 and keeps the state in that state. In the state where negative pressure is generated in the ink 6 and ink is supplied from the common ink flow path to the pressurized liquid chamber 6 through the ink supply path (fluid resistance portion) and the ink meniscus of the nozzle 7 is stabilized to some extent, Transition to the droplet discharge process.
[0048]
A gas chamber 13 between the diaphragm 9 and the individual electrode 12 is filled with a predetermined gas, for example, an inert gas or air. Conventionally, the pressure of the gas in the gas chamber 13 is the same as the atmospheric pressure in a state where the diaphragm 9 is not subjected to electrostatic force and the diaphragm 9 is stationary.
[0049]
However, in the inkjet head 1 of the present embodiment, the pressure in the gas chamber 13 is lower than the atmospheric pressure in a state where the diaphragm 9 is not subjected to electrostatic force and the diaphragm 9 is stationary. It is set lower than 95% of atmospheric pressure.
[0050]
Therefore, in the inkjet head 1, the gas chamber 13 is sealed with the sealing member 14 as described above to reduce the pressure in the gas chamber 13, or the gas chamber 13 is sealed as shown in FIG. 2. 14, the actuator unit 15 is put in the chamber 20 without sealing, and the chamber 20 and the decompression pump 21 are connected by the air guide tube 22. The interior of the chamber 20 is decompressed by the decompression pump 21, and the gas chamber 13 is decompressed. To do.
[0051]
Next, the operation of the present embodiment will be described. As described above, the inkjet head 1 according to the present embodiment seals the gas chamber 13 with the sealing member 14 as described above to decompress the gas in the gas chamber 13, or as shown in FIG. Without sealing the gas chamber 13 with the sealing material 14, the actuator unit 15 is put in the chamber 20, the chamber 20 and the decompression pump 21 are connected by the air conduit 22, and the interior of the chamber 20 is decompressed by the decompression pump 21. Thus, the pressure in the gas chamber 13 is reduced.
[0052]
On the other hand, the air damper effect generated when the diaphragm 9 approaches the individual electrode 12 is a repulsive force generated when the gas in the gas chamber 13 is compressed by the diaphragm 9, and the change in pressure due to the compression of the gas is a temperature change. When is constant, it is expressed by the following Boyle equation.
[0053]
PV = constant (1)
Here, P is the pressure of the gas, and V is the volume of the gas.
[0054]
When this Boyle equation is modified, the air damper effect is that, under the condition that the temperature T is constant, the volume V of the gas chamber 13 is reduced by ΔV by the diaphragm 9, so that the pressure P is expressed by the following equation (2). This can be explained as a phenomenon that increases by ΔP indicated by.
[0055]
ΔP = PV / (V + ΔV) −P (2)
In this equation (2), when the gas pressure P is reduced, the pressure change amount ΔP is reduced as shown in FIG. 3 even if the volume is changed by the same amount as the pressure change amount ΔV.
[0056]
Here, FIG. 3 is a diagram showing the relationship between the pressure P and the pressure change amount ΔP when the volume change amount ΔV is 80% of the volume V of the gas chamber 13, and the horizontal axis indicates the pressure (atmospheric pressure) of the gas. P, the vertical axis represents the gas pressure change ΔP, and both the gas pressure P and the pressure change ΔP are normalized as the pressure when the atmospheric pressure is 1.
[0057]
As can be seen from FIG. 3, the lower the pressure P, the higher the effect of reducing the air damper effect. For example, as an extreme example, if the gas chamber 13 is in a vacuum, the air damper effect is zero. As a practical standard when the actuator unit 15 is used in the inkjet head 1, the degree of reduction of the air damper effect becomes conspicuous from about 95% or less of the atmospheric pressure in FIG.
[0058]
Moreover, since the product of the pressure P and the volume V of the gas chamber 13 increases in proportion to the temperature when the temperature in the actuator unit 15 changes, the inkjet head 1 increases the volume V due to the temperature change as the original pressure P decreases. As a result, the fluctuation of the air damper effect is also reduced. For example, when the inside of the gas chamber 13 is a vacuum, the vacuum remains regardless of the temperature, and the fluctuation becomes zero.
[0059]
In addition, as described above, the inkjet head 1 according to the present embodiment is lower than the atmospheric pressure in a state where the diaphragm 9 is not subjected to electrostatic force and the diaphragm 9 is stationary. It is set lower than 95%.
[0060]
Therefore, the air damper effect can be reduced and driving can be performed with a low driving voltage.
[0061]
4 and 5 are diagrams showing a second embodiment of the actuator and the ink jet head of the present invention, and FIG. 4 is an ink jet head to which the second embodiment of the actuator and the ink jet head of the present invention is applied. FIG. 5 is a partial cross-sectional plan view of the inkjet head 30 of FIG. 4.
[0062]
The present embodiment is applied to an ink jet head similar to the ink jet head 1 of the first embodiment. In the description of the present embodiment, the ink jet head of the first embodiment is used. The same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0063]
In FIG. 4, the ink jet head 30 of the present embodiment communicates with a gas chamber 31 through a communication path 32 and a common gas chamber 33, and each gas chamber 31 further includes a gas as shown in FIG. 5. The chamber 31 is communicated by a chamber communication passage 34 having a predetermined opening diameter formed in the partition wall of the electrode substrate 2 defining the chamber 31.
[0064]
Therefore, in the inkjet head 30 of the present embodiment, the pressure change in each gas chamber 31 escapes to the common gas chamber 33 through the communication path 32 and escapes to the adjacent gas chamber 31 through the inter-chamber communication path 34. The pressure in each gas chamber 31 can be kept uniform.
[0065]
In the present embodiment, the gas chambers 31 communicate with each other through the common gas chamber 33 and the communication path 32, and the gas chambers 31 communicate with each other through the inter-chamber communication path 34. Only one may be used.
[0066]
FIG. 6 is a cross-sectional view of an essential part in the short side direction of an ink jet head 40 to which a third embodiment of the actuator and the ink jet head of the present invention is applied.
[0067]
The present embodiment is applied to an ink jet head similar to the ink jet head 1 of the first embodiment. In the description of the present embodiment, the ink jet head of the first embodiment is used. The same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0068]
In FIG. 6, in the inkjet head 40 of the present embodiment, a through hole 41 is formed in the sealing member 14 that seals the gas chamber 13, and an air guide tube 42 is attached to the through hole 41. The air guide tube 42 is connected to a decompression pump 43, and the gas chamber 13 is decompressed by the decompression pump 43 through the air guide tube 42 and the through hole 41.
[0069]
In order to maintain a predetermined reduced pressure state, at least during the driving of the actuator unit 15, the inkjet head 40 either reduces the pressure during the driving of the actuator unit 15 or starts the pressure reduction before the actuator unit 15 is driven. The actuator unit 15 starts to be driven after a predetermined pressure reduction state.
[0070]
Accordingly, the ink jet head 40 can drive the actuator unit 15 in a predetermined reduced pressure state even when the gas chamber 13 is incompletely sealed, and can reduce the set pressure of the reduced pressure even when the atmospheric pressure fluctuates. It can be easily corrected by changing.
[0071]
FIG. 7 is a cross-sectional view of an essential part in the short side direction of an inkjet head 50 to which the actuator and the fourth embodiment of the inkjet head of the present invention are applied.
[0072]
The present embodiment is applied to an ink jet head similar to the ink jet head 1 of the first embodiment. In the description of the present embodiment, the ink jet head of the first embodiment is used. The same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0073]
In FIG. 7, the inkjet head 50 according to the present embodiment includes a through- hole that is a communication hole that communicates between the gas chamber 13 and the outside to the sealing member 14 that seals between the gas chamber 13 and the outside. 51 is formed, and the outer side of the sealing member 14 in which the through hole 51 is formed opens and closes when the gas flows out from the gas chamber 13 to the outside, and opens from the outside to the gas chamber 13. A check valve 52 that opens and closes the through-hole 51 is attached so as to be closed when gas flows in.
[0074]
Further, in the inkjet head 50, a communication path 53 having a predetermined opening diameter is formed in the partition wall of the electrode substrate 2 that partitions each gas chamber 13, and each gas chamber 13 communicates with the adjacent gas chamber 13 through the communication path 53. Has been.
[0075]
In the inkjet head 50 according to the present embodiment, when the pressure of the gas chamber 13 is increased due to the bending of the vibration plate 9, the check valve 52 is opened and the gas in the gas chamber 13 flows out to the outside. Is reduced, the check valve 52 is closed to prevent the gas from flowing into the gas chamber 13. In addition, when the pressure in a certain gas chamber 13 increases, the ink jet head 50 escapes into the adjacent gas chamber 13 having a lower pressure through the communication hole 53, and the gas chamber 13 When the pressure in 13 becomes lower than the pressure in the adjacent gas chamber 13, gas flows from the adjacent gas chamber 13.
[0076]
Therefore, the actuator unit 15 operates as a decompression pump for decompressing each gas chamber 13 by forming the through-hole 51, the check valve 52, and the communication hole 53, and without providing a decompression pump outside, The chamber 13 can be depressurized. As a result, the inkjet head 50 can be made small and inexpensive.
[0077]
FIG. 8 is a cross-sectional view of an essential part in the short side direction of an ink jet head 60 to which a fifth embodiment of the actuator and the ink jet head of the present invention is applied.
[0078]
The present embodiment is applied to an ink jet head similar to the ink jet head 1 of the first embodiment. In the description of the present embodiment, the ink jet head of the first embodiment is used. The same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0079]
In FIG. 8, in the inkjet head 60 of the present embodiment, a through-hole 61 is formed in the sealing member 14 that seals each gas chamber 13, and outside the sealing member 14 in which the through-hole 61 is formed. Is equipped with a check valve 62 that opens and closes the through-hole 61 by opening and closing outward.
[0080]
In the inkjet head 60 according to the present embodiment, when the pressure of the gas chamber 13 is increased due to the bending of the diaphragm 9, the check valve 62 is opened and the gas in the gas chamber 13 flows out to the outside. Is lowered, the check valve 62 is closed to prevent the gas from flowing into the gas chamber 13.
[0081]
Therefore, the actuator portion 15 operates as a decompression pump for individually decompressing each gas chamber 13 by forming the through-hole 61 and the check valve 62, and without providing a decompression pump outside, the gas chamber 13 Can be depressurized. As a result, the inkjet head 60 can be made small and inexpensive.
[0082]
FIG. 9 is a cross-sectional view of the main part in the short side direction of an ink jet head 70 to which the sixth embodiment of the actuator and the ink jet head is applied.
[0083]
The present embodiment is applied to an ink jet head similar to the ink jet head 1 of the first embodiment. In the description of the present embodiment, the ink jet head of the first embodiment is used. The same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0084]
In FIG. 9, in the inkjet head 70 of the present embodiment, a through hole 71 is formed in the sealing member 14 that seals each gas chamber 13.
[0085]
In the ink jet head 70 of the present embodiment, when the actuator unit 15 is driven, when the vibration plate 9 moves slowly, the gas is discharged from the through hole 71 of the sealing member 14 when the vibration plate 9 moves down to the individual electrode 12 side. Then, when the diaphragm 9 rises in a direction away from the individual electrode 12, the inhalation is performed. Therefore, the pressure in the gas chamber 13 only pulsates, and on average, the pressure does not increase or decrease.
[0086]
However, as the speed of the diaphragm 9 increases, the speed of the gas passing through the through hole 71 of the sealing member 14 cannot catch up with the speed of the diaphragm 9, and when the speed of the diaphragm 9 is sufficiently high, The average pressure is a constant pressure lower than the outside atmospheric pressure.
[0087]
Therefore, the actuator unit 15 acts as a decompression pump, and a compact decompression pump with a small number of parts is formed.
[0088]
The average pressure in the gas chamber 13 at this time is proportional to the ratio of the stroke volume of the diaphragm 9 and the volume of the gas chamber 13, and when the actuator unit 15 is driven with a rectangular pulse voltage waveform, Proportional. The duty is preferably 20% or more, and preferably 50% or more. If the amount is less than this, the loss as a result of the viscosity of the air reduces the effect of the decompression pump.
[0089]
The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the scope of the invention. Needless to say.
[0090]
For example, in each of the above embodiments, the case where the actuator unit is applied to an ink jet head has been described, but the use of the actuator unit is not limited to the ink jet head.
[0091]
【The invention's effect】
As described above, according to the actuator of the present invention, the gas chamber and the outside are sealed with the sealing member, and the sealing member has the communication hole that communicates between the gas chamber and the outside. An open / close valve is formed in the communication hole that opens when the gas flows out from the gas chamber and closes when the gas flows from the outside into the gas chamber. Since the pressure is reduced, the air damper effect with respect to the displacement of the diaphragm can be reduced and driven with a low driving voltage.
[0092]
According to the ink jet head according to the present invention, since the actuator according to the present invention is provided, the ejection performance is improved. According to the ink jet recording apparatus of the present invention, since the ink jet head according to the present invention is provided, the image quality is improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part in a short side direction of an ink jet head to which a first embodiment of an actuator and an ink jet head of the present invention is applied.
2 is a cross-sectional view of an essential part showing an example in which the gas chamber is decompressed by inserting an actuator into the chamber without sealing the gas chamber of the inkjet head of FIG. 1;
FIG. 3 is a diagram showing the relationship between the pressure and the amount of change in pressure when the volume of the gas chamber in FIG. 1 is 80%.
FIG. 4 is a cross-sectional view of an essential part in the short side direction of an ink jet head to which a second embodiment of an actuator and an ink jet head of the present invention is applied.
5 is a partial cross-sectional plan view of the inkjet head of FIG. 4;
FIG. 6 is a cross-sectional view of an essential part in the short side direction of an inkjet head to which a third embodiment of an actuator and an inkjet head of the present invention is applied.
FIG. 7 is a cross-sectional view of an essential part in a short side direction of an ink jet head to which a fourth embodiment of an actuator and an ink jet head of the present invention is applied.
FIG. 8 is a cross-sectional view of an essential part in a short side direction of an ink jet head to which a fifth embodiment of an actuator and an ink jet head of the present invention is applied.
FIG. 9 is a cross-sectional view of an essential part in a short side direction of an ink jet head to which a sixth embodiment of an actuator and an ink jet head of the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inkjet head 2 Electrode board | substrate 3 Vibrating plate board | substrate 4 Liquid chamber board | substrate 5 Nozzle plate 6 Pressurizing liquid chamber 7 Nozzle 8 Recessed part 9 Vibrating plate 10 Hole 11 Recessed part 12 Individual electrode 13 Gas chamber 14 Sealing member 15 Actuator part 16 Insulating layer 20 Chamber 21 Depressurization pump 22 Intake pipe 30 Inkjet head 31 Gas chamber 32 Communication path 33 Common gas chamber 34 Inter-chamber communication path 40 Inkjet head 41 Through hole 42 Induction pipe 43 Decompression pump 50 Inkjet head 51 Through hole 52 Check valve 53 Communication path 60 Inkjet head 61 Through-hole 62 Check valve 70 Inkjet head 71 Through-hole

Claims (3)

The diaphragm and the electrode are arranged opposite to each other with a predetermined gap forming a gas chamber, and the diaphragm is displaced in the electrode direction by electrostatic force by applying a voltage between the diaphragm and the electrode. In the actuator where the diaphragm is restored by stopping the application of the voltage ,
The space between the gas chamber and the outside is sealed with a sealing member,
The sealing member is formed with a communication hole that communicates between the gas chamber and the outside.
The communication hole is provided with an opening / closing valve that opens when gas flows out from the gas chamber to the outside, and closes when gas flows from the outside into the gas chamber,
The actuator, wherein the gas chamber is depressurized by repeatedly displacing the diaphragm. An ink jet head comprising the actuator according to claim 1 . An inkjet recording apparatus comprising the inkjet head according to claim 2.

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