JP5073561B2 - Electrostatic actuator, method for manufacturing the same, droplet discharge head, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrostatic actuator, a manufacturing method thereof, a droplet discharge head, and an image forming apparatus.

  A liquid droplet ejection head used in an image recording apparatus such as a printer, a facsimile apparatus, a copying apparatus, or a plotter or an ink jet recording apparatus used as an image forming apparatus includes a nozzle that ejects liquid droplets and a liquid chamber (discharge chamber) that communicates with the nozzle. And an actuator means for generating energy for pressurizing the ink in the liquid chamber, and pressure is applied to the recording liquid in the liquid chamber by the energy generated by the actuator means. Droplets are ejected from the nozzle.

  Droplet discharge heads that use piezoelectric actuators such as electromechanical transducers, those that use thermal actuators that use film boiling for electrothermal transducers, and electrostatic forces between the diaphragm and electrodes Some of them use electrostatic actuators. Among them, droplet discharge heads using electrostatic actuators are smaller than other types of droplet discharge heads in terms of size, speed, density, and power saving. Because of its superiority, development is actively underway.

  The driving of an electrostatic actuator used in an electrostatic drive type liquid droplet ejection head includes non-contact driving that does not contact the diaphragm and the counter electrode, and contact driving that contacts the diaphragm and the counter electrode. is there. In non-contact driving in which the diaphragm and the counter electrode are not in contact, a much larger voltage is required than in the case of contact driving in order to obtain a large generated force, which increases the cost of the drive element and the like. On the other hand, a large driving force can be obtained in the contact drive in which the diaphragm and the counter electrode are in contact. However, if the contact drive in which the diaphragm and the counter electrode are contacted repeatedly, electrostatic attraction characteristics or electrostatic Phenomena such as a phenomenon in which the rebound characteristics are deteriorated or an insulating film is peeled off from the electrode surface and the insulation property is hindered and the electrostatic actuator is destroyed.

  In order to avoid the adverse effect at the time of the contact drive of the electrostatic actuator, the inkjet head disclosed in Patent Document 1 is subjected to a hydrophobic treatment on the actuator surface. Further, in order to obtain sufficient durability of the hydrophobic film, a gas (vapor) of a hydrophobic agent having a predetermined concentration or more is hermetically sealed in a gap between the diaphragm and the electrode. At this time, by connecting a plurality of gaps with communication paths (bypass pipes) and introducing a hydrophobic agent from one place or a small number of places, it is possible to perform sealing in a short time and improve airtightness. It is also possible.

  In addition, the electrostatic actuator disclosed in Patent Document 2 is configured such that when the air opening hole (hydrophobic agent introduction hole) is sealed with a sealant, the sealant is connected between the diaphragm and the electrode through the communication path by capillary action. In order to prevent it from reaching the gap between them and being unable to operate normally, it forms resistance to the inflow of the sealant into the communication path, and forms a meandering path for increasing the distance, Intrusion of the sealant into the gap is prevented.

  In addition, the electrostatic actuator disclosed in Patent Document 3 is a hydrophobic agent that forms a hydrophobic film inside the gap between the diaphragm and the electrode in the case where the gap between the diaphragm and the electrode is formed by sacrificial layer etching. In order to efficiently introduce the vapor into the gap, a portion for forming the common communication path is formed when patterning the individual electrode formation layer, and the common communication path of the insulating film on the electrode formation layer is formed. By forming an opening at a location and forming a portion for forming a common communication path in the sacrificial layer deposited thereon, the electrode forming layer and the portion for forming the common communication path are integrally formed with the sacrificial layer. After the formation, the sacrificial layer is removed by etching to form a common communication path having a height higher than the gap.

Furthermore, in Patent Document 2 and Patent Document 3, various proposals have also been made regarding the arrangement of the air opening holes and the communication paths in order to efficiently introduce the hydrophobic agent and improve the uniformity between the voids.
Japanese Patent No. 4038864 JP 2007-77864 A JP 2006-115624 A

  As described above, even when the hydrophobic agent vapor is introduced into the gap between the diaphragm and the electrode, if the sealing of the air opening hole (hydrophobic agent introduction hole) is not complete, the concentration of the hydrophobic agent in the gap is changed over time. There is a disadvantage that the durability of the electrostatic actuator deteriorates due to the decrease.

  The present invention improves such disadvantages and prevents deterioration in durability by preventing a decrease in the concentration of the hydrophobic agent in the gap over time even when the sealing performance of the air opening hole (hydrophobic agent introduction hole) is not perfect. It is an object of the present invention to provide an electrostatic actuator that can be prevented, a manufacturing method thereof, a droplet discharge head, and an image forming apparatus.

  The electrostatic actuator according to the present invention includes a deformable diaphragm, at least a part of which is a movable electrode, and a fixed electrode disposed opposite to the diaphragm via a gap, and the movable electrode and the fixed electrode In an electrostatic actuator that deforms the diaphragm by an electrostatic force generated when a voltage is applied between the electrodes, the atmosphere opening having a communication path that communicates with the gap and an atmosphere opening hole that communicates the communication path with the outside. And a hydrophobic agent holding portion in contact with the communication path, a hydrophobic film is formed on the surface of the diaphragm and the fixed electrode on the gap side, and a hydrophobic agent vapor having a hydrophobic group in the gap And a hydrophobic hydrophobic agent is held in the hydrophobic agent holding portion.

  A membrane that does not allow liquid hydrophobic agent to pass but allows hydrophobic agent vapor to pass therethrough is provided between the communication path communicating with the gap and the hydrophobic agent holding portion.

  Moreover, it is good to arrange | position an absorber in the said hydrophobic agent holding | maintenance part, and hold | maintain a liquid hydrophobic agent in an absorber.

  Another electrostatic actuator according to the present invention includes a deformable diaphragm, at least a part of which is a movable electrode, and a fixed electrode disposed opposite to the diaphragm with a gap between the movable electrode and the movable electrode. In the electrostatic actuator that deforms the diaphragm with an electrostatic force generated when a voltage is applied between the fixed electrodes, a communication path that communicates with the gap, and an atmosphere opening portion that includes the communication path and an atmosphere opening hole. And a hydrophobic film is formed on the surface of the diaphragm and the fixed electrode on the gap side, and a vapor of a hydrophobic agent having a hydrophobic group is enclosed in the gap. In addition, a liquid hydrophobic agent is held in the hydrophobic agent holding portion.

  In another electrostatic actuator of the present invention, the side of the communicating path of the hydrophobic agent holding portion may have a meandering shape so that a liquid hydrophobic agent does not flow into the gap.

  The manufacturing method of the electrostatic actuator according to the present invention includes a deformable diaphragm at least a part of which is a movable electrode, a fixed electrode disposed opposite to the diaphragm via a gap, the diaphragm and the diaphragm A hydrophobic film formed on the surface of the fixed electrode on the space side, a communication path provided in communication with the space, an air release portion having an air release hole for communicating the communication path with the outside, and the communication path A method for manufacturing an electrostatic actuator having a hydrophobic agent holding portion in contact with the diaphragm and deforming the diaphragm with an electrostatic force generated when a voltage is applied between the movable electrode and the fixed electrode, After sealing a hydrophobic agent vapor having a hydrophobic group, liquid hydrophobic agent is injected into the hydrophobic agent holding portion and sealed.

  The droplet discharge head according to the present invention includes the electrostatic actuator, and deforms the diaphragm with an electrostatic force generated when a voltage is applied between the movable electrode and the fixed electrode, thereby dropping droplets from the nozzle. It is made to discharge.

  The image forming apparatus of the present invention includes the droplet discharge head, and records an image by discharging ink droplets from nozzles of the droplet discharge head.

  The electrostatic actuator according to the present invention forms a hydrophobic film on the surface of the diaphragm and the fixed electrode on the gap side, encloses a vapor of a hydrophobic agent having a hydrophobic group in the gap, and is in contact with the communication path communicating the gap. Since the hydrophobic agent holding part that holds the liquid hydrophobic agent is provided, the hydrophobic agent holding part that holds the liquid hydrophobic agent is more effective than the hydrophobic agent holding part that holds the liquid hydrophobic agent even if the sealing of the hydrophobic agent vapor in the gap is slightly incomplete. Since the steam is supplied, it is possible to prevent a decrease in the concentration of the hydrophobic agent in the gap and to deteriorate the durability of the electrostatic actuator.

  In addition, by providing a membrane that does not allow the liquid hydrophobic agent to pass but allows the vapor of the hydrophobic agent to pass between the communication path communicating with the gap and the hydrophobic agent holding portion, the liquid hydrophobic agent can be prevented from entering the gap. The electrostatic actuator can be driven stably.

  Furthermore, by disposing the absorber in the hydrophobic agent holding portion and holding the hydrophobic agent in the absorber, it is possible to prevent the liquid hydrophobic agent from entering the gap.

  Further, by providing a hydrophobic agent holding portion between the communication path communicating with the gap and the atmosphere opening portion having the atmosphere opening hole, the hydrophobic agent holding portion is held between the gap and the hydrophobic agent holding portion. It can be formed simultaneously with the communication path, and the manufacturing process can be simplified. Also, the communicating path side of the hydrophobic agent holding portion has a meandering shape, so that the liquid hydrophobic agent can be surely prevented from flowing into the gap and the electrostatic actuator can be driven stably.

  In addition, the droplet discharge head provided with this electrostatic actuator can improve durability and stably discharge droplets, thereby improving reliability.

  Further, an image forming apparatus that has this droplet discharge head and discharges ink droplets from the nozzles of the droplet discharge head to record an image stably discharges ink droplets. As well as forming, durability and reliability can be improved.

  1 to 9 show the configuration of the droplet discharge head of the present invention, FIG. 1 is an exploded perspective view, FIG. 2 is a plan view showing a see-through state, FIG. 3 is a sectional view taken along line X11-X11 in FIG. 2 is a sectional view taken along line X12-X12 in FIG. 2, FIG. 5 is a sectional view taken along line X13-X13 in FIG. 2, FIG. 6 is a sectional view taken along line Y11-Y11 in FIG. 2 is a cross-sectional view of Y13-Y13, and FIG. 9 is an enlarged view of the periphery of the open hole.

  The droplet discharge head 1 uses an electrostatic actuator as pressure generating means, and includes an actuator substrate 10, a liquid chamber substrate 30, a nozzle plate 40 having a plurality of nozzle holes 41, a frame (not shown), an FPC, and a driver. It consists of IC.

  The nozzle plate 40 is, for example, a polyimide film in which a water repellent film is coated on the paper surface (upper surface side in FIG. 2), and the nozzle hole 41 is opened by laser processing after the nozzle plate 40 is bonded to the liquid chamber substrate 30. It is a thing. The liquid chamber substrate 30 has an opening 42 at a portion corresponding to the liquid hydrophobic agent holding portion (liquid hydrophobic agent injection portion) 52. Although the opening 42 is opened in such a manner that only a portion that needs to be opened is opened, it may be cut out linearly. Alternatively, the nozzle plate 40 and the liquid chamber substrate 30 may be bonded and then opened, or a previously opened one may be bonded.

  As the liquid chamber substrate 30, a silicon substrate having a crystal orientation (110) is used, and a common liquid chamber 31, a fluid resistance portion 32, and a pressurized liquid chamber 33 are formed on the surface opposite to the nozzle plate 40. Further, a communication pipe 34 for communicating the nozzle hole 41 and the pressurized liquid chamber 33 is formed through the liquid chamber substrate 30. By adopting such a configuration, the height of the pressurized liquid chamber 33 can be made lower than the thickness of the liquid chamber substrate 30, and the pressurized liquid chamber 33 can be formed while using a substrate having a thickness that is easy to handle. The height can be optimized from the viewpoint of ejection characteristics. The thickness of the liquid chamber substrate 30 is, for example, 400 μm, and the height of the pressurized liquid chamber 30 is 80 μm. In addition, since a silicon substrate having a crystal orientation (110) is used as the liquid chamber substrate 30, the pressurized liquid chamber 33 and the like can be processed with high accuracy by known anisotropic etching. Also, as shown in FIG. 4, after forming the pressurized liquid chamber 33 and others, an oxide film to be a liquid chamber substrate wet film 35 is formed on the surface by thermal oxidation, thereby improving wettability and discharging liquid such as ink. This is intended to prevent corrosion of silicon, which is a base material. At this time, although not shown, a dummy pattern is provided on the adhesive surface side of the liquid chamber substrate 30 with the nozzle plate 40 to prevent the substrate from warping due to internal stress of the oxide film after thermal oxidation. Here, depending on the type of discharge liquid, the liquid chamber substrate wetted film 35 may be unnecessary or may be another film.

  The actuator substrate 10 includes a diaphragm 20, a gap 15a, and a fixed electrode layer formed on a silicon substrate 11 having a crystal orientation (100) by a sacrificial layer process capable of forming a gap with high accuracy via a substrate insulating film 12. An electrostatic actuator composed of a fixed electrode 13 a formed on 13 is formed. The actuator substrate 10 is formed with a communication path 53 that communicates the gaps 15 a with each other in the direction in which the nozzle holes 41 are arranged, and the other end of the communication path 53 is an opening that connects the inside of the communication path 53 and the outside of the actuator substrate 10. It communicates with the hole 51. Further, in order to supply the discharge liquid from the surface opposite to the liquid chamber substrate 30 of the actuator substrate 10 (hereinafter referred to as the back surface), a liquid supply path 60 is provided through the surface, as shown in FIG. A liquid supply passage liquid contact film 61 is formed on the surface.

  The diaphragm 20 is formed of a laminated film. As shown in FIG. 3, the diaphragm side insulating film 21, the diaphragm electrode layer 22, the tensile stress film 23, the sacrificial layer removing hole sealing film 24, and the liquid contact are formed from the gap 15a side. The film 25 is formed. The diaphragm-side insulating film 21 prevents a short circuit when the diaphragm 20 and the fixed electrode 13a contact each other, and is formed of a silicon oxide film. The diaphragm electrode layer 22 has a diaphragm electrode 22a that generates an electrostatic force by applying a voltage to the fixed electrode 13a, and is formed of, for example, an arsenic doped polysilicon film. The tensile stress film 23 is used to make the diaphragm 20 as a whole to have a tensile stress so that the diaphragm 20 is not stretched and secures a repulsive force during driving. The tensile stress film 23 is formed of, for example, a silicon nitride film. The sacrificial layer removal hole sealing film 24 serves to both seal the sacrificial layer removal hole and prevent cracking of the tensile stress film 23, and is formed of, for example, a silicon oxide film. The liquid contact film 25 is made of, for example, PBO (polybenzoxazole) in order to prevent corrosion due to a discharge liquid such as ink. Here, a silicon oxide film may be provided between the diaphragm electrode layer 22 and the tensile stress film 23 as a diaphragm deflection preventing film.

  Phosphorous-doped polysilicon is used for the fixed electrode layer 13, and a silicon oxide film is formed as an insulating film on the gap 15a side. In addition, a silicon oxide film is formed as the substrate insulating film 12 between the fixed electrode layer 13 and the silicon substrate 11 to ensure insulation between the fixed electrode layer 13 and the silicon substrate 11. Here, one of the diaphragm electrode 22a and the fixed electrode 13a is an individual electrode separated into nozzles (channels), and the other is a plurality of nozzles (channels), for example, nozzles that discharge as a common electrode common to all nozzles (channels). (Channel) can be selected. Here, the diaphragm electrode 22a is a common electrode, and the fixed electrode 13a is an individual electrode.

  The gap 15a and the communication path 53 were formed by a sacrificial layer process using polysilicon as a sacrificial layer. The sacrificial layer removal hole and the detailed structure around it in this sacrificial layer process are not shown in the figure, but have the same configuration as in Patent Document 2. The diaphragm electrode 22a and the fixed electrode 13a are formed of polysilicon like the sacrificial layer, but as described above, the portion facing the portion that becomes the gap 15a is a silicon oxide film provided as an insulating film. Etching at the time of sacrificial layer removal by removing the sacrificial layer using an etchant having sufficient selectivity between polysilicon and silicon oxide film, for example, TMA (tetramethylammonium hydroxide) aqueous solution. To prevent it.

  As for the communication path 53, as disclosed in Patent Document 3, the polysilicon of the fixed electrode layer 13 is also used as a sacrificial layer for forming the communication path, thereby increasing the conductance of the communication path 53. As in Patent Documents 1 to 3, by introducing hexamethyldisilazane (HMDS) vapor through the communication path 53, a hydrophobic film is formed on the surface of the diaphragm 20 and the fixed electrode side insulating film 14 on the gap 15a side, HMDS vapor is sealed in the gap 15a to ensure the driving durability of the electrostatic actuator.

  The opening hole 51 of the actuator substrate 10 has a first opening hole 51a and a second opening hole 51b. The first opening hole 51a is a PBO film (hereinafter referred to as a PBO film formed simultaneously with the formation of the diaphragm wetted film 25). The second open hole 51b is sealed with a sealant 54a made of, for example, an ultraviolet curable epoxy resin. As shown in FIG. 9, a plurality of first open holes 51a having an opening diameter of about 2 μm are formed. The diaphragm wetted film 25 covering the first open hole 51a is formed so as to cover only the surface without entering the first open hole 51a. On the other hand, the second opening hole 51b has a size of an opening diameter of about 30 μm, and the vicinity thereof is a meandering passage so that the sealant 54a enters the second opening hole 51b and the meandering passage to some extent.

  As shown in FIG. 4, a recess 37 is formed in the liquid chamber substrate 30 in the portion of the sealant 54a that seals the second open hole 51b, and the actuator substrate 10 and the liquid chamber substrate due to the rise of the sealant 54a. This prevents 30 joint failures. If the sealant 54a does not rise here, the depression 37 is unnecessary. In addition, as shown in FIG. 5, a penetrating portion is provided so as to cover the first open hole 51 a to form a hydrophobic agent holding portion 52. A liquid hydrophobic agent 52a is held in the hydrophobic agent holding portion 52, and the nozzle plate 40 side of the hydrophobic agent holding portion 52 is sealed with a sealing agent 54b.

  In the figure, the nozzle hole 42 is drawn upward. However, for example, when the recording liquid ejection head is mounted in image formation, the nozzle hole 42 is mounted downward. Therefore, in a state of being mounted on the apparatus, the liquid hydrophobic agent 52a is accumulated on the nozzle hole 42 side, and the actuator substrate 10 side becomes a space (gas portion). The PBO film, which is a material for forming the diaphragm wetted film 25 that covers the first open hole 51a, does not allow liquid to pass therethrough, but is slightly permeable, and when the HMDS concentration in the gap 15a and the communication path 53 is reduced. HMDS vapor is supplied through the BBO membrane.

  As described above, since the hydrophobic agent holding portion 52 that holds the liquid hydrophobic agent 52a is provided in contact with the communication passage 53 that communicates with the gap 15a, the liquid hydrophobic agent is held even if the sealing is slightly incomplete. Hydrophobic agent vapor is supplied from the portion 52 to prevent a decrease in the concentration of the hydrophobic agent in the gap 15a, thereby preventing durability deterioration of the electrostatic actuator. Here, the liquid hydrophobic agent holding part 52 is a simple space formed in the liquid chamber substrate 30, but an absorbent body made of, for example, a porous material may be arranged in this part to hold the liquid hydrophobic agent.

  FIGS. 10 to 13 show other configurations and arrangements of the opening 51 and the hydrophobic agent holding portion 52 that holds the liquid hydrophobic agent 52a. As shown in FIG. 10, the nozzle side can be narrowed so that the shape of the hydrophobic agent holding portion 52 can be easily sealed with the sealing agent 54b. Moreover, as shown in FIG. 11, you may form the hydrophobic agent holding | maintenance part 52 so that both the 1st open hole 51a and the 2nd open hole 51b may be covered. In addition, as shown in FIG. 12, the second open hole 51b is formed on the side of the communication path 53 communicating with the gap 15a rather than the first open hole 51a, and the hydrophobic of the liquid is formed so as to cover the second open hole 51b. The hydrophobic agent holding part 52 that holds the agent 52a may be formed. In such a configuration, the air permeability of the second open hole 51b portion depends on the type of sealing agent 54a, the coating thickness, whether or not it enters the meander, or the amount of penetration, but the first open hole 51a portion. Is extremely smaller than the air permeability of the material (including the material permeability, thickness, and cross-sectional area). It does not compensate for a decrease in the HMDS concentration in the gap 15a due to completeness or the like. On the other hand, even if the diaphragm wetted film 25 enters the inside of the first opening hole 51a from the opening hole 51a, it is not affected.

  In the above description, an example in which the first atmosphere opening hole 51a and the second atmosphere opening hole 51b are arranged in series has been shown. However, as shown in FIG. 13, the first opening hole 51a and the second opening hole 51b. May be arranged in parallel.

  A manufacturing process for forming the first air opening hole 51a, the second air opening hole 51b, and the hydrophobic agent holding portion 52 to seal the hydrophobic agent 52a will be described with reference to the flowchart of FIG. 14 and the process diagram of FIG. To do.

  First, the main part of the electrostatic actuator of the actuator substrate 10 is formed using a sacrificial layer process as in the known example (step S1). Since the sacrificial layer removal hole is sealed with a silicon oxide film formed by a low pressure CVD method when forming the main part of the electrostatic actuator, in this state, the space 15a is held at a low pressure, and vibration is generated in a normal temperature / normal pressure environment. The plate 20 is pushed by the atmospheric pressure and bent toward the fixed electrode 13a. Next, as shown in FIG. 15A, the first open hole 51a is opened in the diaphragm 20 by photolithography etching (step S2). As a result, the pressure in the gap 15a can be made equal to the external pressure, and the bending of the diaphragm 20 is eliminated.

  Next, as shown in FIG. 15B, a PBO film to be the diaphragm wetted film 25 is formed by a coating method (step S3). When the diaphragm wetted film 25 is formed, a solution containing a precursor that becomes PBO is applied to the surface of the actuator substrate 10 by spin coating, and then soft-baked to volatilize the solvent. Then, the PBO unnecessary portion is exposed by mask exposure and immersed in an alkaline solution to remove the PBO precursor film in the exposed portion, and hard-baked at a temperature of about 320 ° C. to form PBO. Thus, a PBO film can be easily formed only on a desired portion using a photosensitive material. Due to the formation of the diaphragm wetted film 25, the first open hole 51a is also covered with the PBO film. Although this PBO film is permeable but does not transmit liquid, even if the surface of the actuator substrate 10 is exposed to a liquid, for example, a resist solution, an etching solution, a stripping solution, pure water, a liquid hydrophobic agent, or the like in a later process. These liquids are prevented from entering the passage 53 and the gap 15a.

  Next, the liquid supply path 60 and the liquid supply path wetted film 61 are formed on the actuator substrate 10 (step S4). The liquid supply path 60 is formed by a known photolithography / etching process. That is, when the liquid supply path 60 is formed, the oxide film / nitride film laminated film on the surface of the actuator substrate 10 is a normal dry etcher using a resist having an opening in the portion where the liquid supply path 60 is formed as a mask. 11 etches with a silicon deep dry etcher. In addition, it is possible to use a method of forming by water laser or sand blasting. Further, the liquid supply path wetted film 61 attaches a solution containing a PBO precursor to the inner wall of the liquid supply path 60 by spray coating from the back side of the actuator substrate 10, and then performs solvent volatilization and PBO by soft baking and hard baking. To do.

  Next, as shown in FIG. 15C, the second opening hole 51b is opened (step S5). The second open hole 51b is opened by dry etching using, for example, the diaphragm wetted film 25 that has previously been opened as a mask. At this time, the hard mask 55 that is slightly larger than the opening is covered except for the vicinity of the second open hole 51b to prevent damage during dry etching. Thereafter, as shown in FIG. 15 (d), the diaphragm wetted film 25 in the portion damaged by the etching with oxygen plasma and the deposits during the oxide film dry etching are removed.

  Next, the void hydrophobization process is performed (step S6). In this intracavity hydrophobization treatment, gas that becomes a hydrophobic film such as HMDS (hexamethyldisilazane) is introduced from the second open hole 51b to the gap 15a through the communication path 53, and the diaphragm-side insulating film 21 and the fixed electrode. The portion of the side insulating film 14 facing the gap 15a is subjected to a hydrophobic treatment. At this time, as disclosed in Patent Document 1, it is desirable to perform a pretreatment (drying) step to reduce moisture adhering to the surface as much as possible. For example, a vacuum heating process in which the actuator substrate 10 is left in a processing tank supplied with dry air and the inside of the processing tank is heated to a vacuum, a process of alternately switching the inside of the processing tank to a vacuum atmosphere and a nitrogen atmosphere, and a combination thereof. It can be employed as a pretreatment step. Also, in the hydrophobic film forming process, similarly to the one disclosed in Patent Document 1, a container containing the actuator substrate 10 and a liquid phase HMDS is placed in a treatment tank, and HMDS vapor is generated at normal temperature and normal pressure. It is left until it sufficiently penetrates into the gap 15a by diffusion. Alternatively, the actuator substrate 10 is immersed in a container containing the liquid phase HMDS in a decompressed treatment tank to introduce the liquid phase HMDS into the gap 15a, and then the actuator substrate 10 is placed in another treatment tank. The liquid phase HMDS may be removed by evaporation from the inside of the gap 15a by heating. At this time, an appropriate HMDS vapor is introduced into the heat treatment tank so that a desired concentration of HMDS vapor remains in the gap 15a.

  Next, as shown in FIG. 15E, the second open hole 51b is sealed (step S7). In the step of sealing the second opening hole 51b, the actuator substrate 10 is taken out from the hydrophobic treatment tank, and the second opening hole 51b is immediately hermetically sealed with the sealing agent 54a. As the sealant 54a, an ultraviolet curable epoxy resin or the like can be used. Thereafter, as shown in FIG. 15 (f), the liquid chamber substrate 20 and the actuator substrate 10 are bonded together, and the nozzle plate 40 having the nozzle holes 41 and the openings 42 is adhered with an adhesive as in the known example (step). S8). And as shown in FIG.15 (g), HMDS used as the liquid hydrophobic agent 52a is inject | poured into the hydrophobic agent holding | maintenance part 52 from the opening part 42 of the nozzle plate 40, and an opening part is sealed with the sealing agent 54b (FIG. 15G). Step S9). As the sealant 54b, an ultraviolet curable epoxy resin or the like can be used as in the sealant 54a. In this way, the hydrophobic agent 52a is sealed with the sealing agent 54b.

  Next, an arrangement example of the first atmosphere opening hole 51a, the second atmosphere opening hole 51b, and the communication path 53 will be described with reference to FIGS. FIG. 16 shows an example in which the first atmosphere opening hole 51a and the second atmosphere opening hole 51b provided in one place in the chip are communicated from one end of each gap 15a through the communication path 53, and FIG. The first air opening hole 51a and the second air opening hole 51b are provided at two locations on both sides of the chip so that the hydrophobic agent can be introduced in a shorter time, and at the same time, the HMDS concentration in the gap 15a is suppressed from being reduced. It is designed to be more stable. In FIG. 18, the first atmosphere opening holes 51a are further effectively provided at two positions on both sides of the gap 15a via the communication path 53 and a total of four positions in the chip. In FIG. 19, the arrangement in which the communication passages 53 are provided from both ends of each gap 15a is the same as the arrangement example of FIG. 18, but the first atmosphere opening hole 51a and the second atmosphere opening hole 51b are connected to both sides of the communication path. As common to 53, the number of air opening holes is reduced. In the case of the arrangement shown in FIG. 19, the introduction of the hydrophobic agent and the suppression of the decrease in the HMDS concentration remain the same as the configuration of FIG. It becomes. Further, although not shown in the drawings, as disclosed in Patent Document 2, each gap 15a is grouped according to the required number, and each gap group is arranged so as to branch and form a sub-common communication path. The hydrophobic agent may be introduced uniformly into 15a. The same applies to the arrangement of the opening hole 51 and the hydrophobic agent holding portion 52 shown in FIGS. 11 to 13, and various other arrangement examples are conceivable.

  Next, with respect to the second droplet discharge head 1a, an exploded perspective view showing component configurations of the nozzle substrate, the liquid chamber substrate, and the actuator substrate of FIG. 20, and a perspective state plane arrangement of the nozzle substrate, the liquid chamber substrate, and the actuator substrate of FIG. A description will be given with reference to the cross-sectional view taken along the line Y21-Y21 in FIG.

  The electrostatic actuator of the droplet discharge head 1a has the same configuration as that of the droplet discharge head 1, but has a configuration in which only one type of opening hole 51 is provided. The electrostatic actuator of the droplet discharge head 1 opens the first open hole 51a and allows the inside of the gap 15a to communicate with the outside world, thereby eliminating the bending of the vibration plate 20 in the normal pressure environment. Although the diaphragm wetted film 25 was formed, the electrostatic actuator of the droplet discharge head 1a formed a polyparaxylylene film by vacuum deposition to form the diaphragm wetted film 25. For this reason, there is no need to set the air gap 15a to atmospheric pressure when the diaphragm wetted film 25 is formed, and the opening hole 51 can be of only one type. Moreover, although the diaphragm wetted film 25 is not necessary depending on the type of the discharged liquid, such a configuration can also be adopted in that case.

  A manufacturing process for sealing the hydrophobic agent 52a by forming the air opening hole 51 and the hydrophobic agent holding portion 52 of the electrostatic actuator of the droplet discharge head 1a with reference to the flowchart of FIG. 23 and the process diagram of FIG. explain.

  First, as shown in FIG. 24A, the main part of the actuator substrate 10 is formed by a sacrificial layer process (step S11). In this process, the sacrificial layer removal hole is sealed with a silicon oxide film formed by a low pressure CVD method, and thus the inside of the gap 15a is kept at a low pressure in this state. Next, the liquid supply path 60 is formed in the actuator substrate 10 by a photolithography / etching process (step S12). Next, as shown in FIG. 24B, a polyparaxylylene film that will be the diaphragm wetted film 25 and the liquid supply path wetted film 61 is simultaneously formed by vacuum deposition (step S13). In this method, a film is formed almost uniformly on the exposed portion in the vapor deposition chamber. After the film formation, polyparaxylylene formed on unnecessary portions such as the electrical connection portion 29 is removed by a normal photolithography / etching process. At this time, the polyparaxylylene in the portion that opens the open hole 51 is also removed. Etching is easily performed with oxygen plasma. In addition, although the resist used as a mask is also etched, it can be used as a mask by making it sufficiently thicker than the polyparaxylylene film. Thereafter, the resist is removed with a stripping solution. Next, as shown in FIG. 24C, an opening is formed by dry etching using the diaphragm wetted film 25 having a portion where the opening 51 is previously formed as a mask (step S14). At this time, the hard mask 55 that is slightly larger than the opening is covered except for the vicinity of the open hole 51 to prevent damage during dry etching. Thereafter, the portion of the diaphragm wetted film 25 damaged by the etching with oxygen plasma and the deposits during the oxide film dry etching are removed.

  Thereafter, as shown in FIG. 24 (d), a gas that becomes a hydrophobic film such as HMDS is introduced from the open hole 51 into the gap 15 a through the communication path 53, and the gap between the diaphragm side insulating film 21 and the fixed electrode side insulating film 14 is introduced. Hydrophobization of the portion facing 15a is performed (step S15). In this hydrophobization treatment, a desired concentration of HMDS vapor is left in the gap 15a. Next, the actuator substrate 10 is taken out from the hydrophobic treatment tank, and the open hole 51 is immediately hermetically sealed with the sealant 54a (step S16). As the sealing agent 54a, as described above, an ultraviolet curable epoxy resin or the like can be used. Thereafter, the liquid chamber substrate 30 and the actuator substrate 10 are bonded together (step S17), HMDS that becomes the liquid hydrophobic agent 52a is injected into the hydrophobic agent holding portion 52 from the opening portion 42 of the nozzle plate 40, and the opening portion is sealed. Sealing is performed at 54b (step S18).

  Next, the third droplet discharge head 1b will be described with reference to the sectional views of FIGS. In any of the cases shown in FIGS. 25 to 27, the electrostatic actuator of the droplet discharge head 1b has the absorber disposed in the liquid hydrophobic agent holding portion 52 to hold the liquid hydrophobic agent in the absorber and the second opening. The holes 51b are not sealed and are left open. With such a configuration, it is possible to easily supply the hydrophobic agent vapor from the hydrophobic agent holding portion 52 to the gap 15a. The rest is the same as the electrostatic actuator of the droplet discharge head 1. Further, the manufacturing process can be obtained by omitting the step of sealing the second open hole 51b after the hydrophobic treatment in the gap in the configuration shown in FIG. 25 and arranging the absorber so as to cover the open hole 51. . Further, in the configuration shown in FIG. 26, the step of sealing the second opening hole 51b is omitted, and the second opening hole 51b is obtained by placing it in the hydrophobic agent holding portion 52 provided in the liquid chamber substrate 30 in advance. 27 can be obtained by including a hydrophobic agent in the absorber before the actuator substrate 10 and the liquid chamber substrate 30 are bonded together after the absorber is disposed. Further, although not shown, the absorber can be arranged on the liquid chamber substrate 30 side in the configuration of FIG.

  Next, with respect to the fourth droplet discharge head 1c, an exploded perspective view showing component configurations of the nozzle substrate, the liquid chamber substrate, and the actuator substrate of FIG. 28, and a perspective plane arrangement of the nozzle substrate, the liquid chamber substrate, and the actuator substrate of FIG. This will be described with reference to FIG. 29 and the X41-X41 cross-sectional view of FIG. 29 shown in FIG. 30 and the Y42-Y42 cross-sectional view of FIG. 29 shown in FIG.

  The electrostatic actuators from the droplet discharge head 1 to the droplet discharge head 1b form the liquid hydrophobic agent holding portion 52 on the liquid chamber substrate 30, whereas the droplet discharge head 1c uses the liquid-hydrophobic agent holding portion as a liquid-hydrophobic material. It is set as the agent holding | maintenance part and it is set as the structure sealed around with the sealing agent 54b by resin materials etc. Since the liquid hydrophobic agent is held by the absorbent body, as shown in the cross-sectional view of FIG. 32, the first opening hole 51a may not be sealed with the sealing agent 54a. Various modifications can be adopted for the arrangement of the opening hole 51, the liquid hydrophobic agent holding part 52, and the communication path 43. Such a configuration can also be applied when the electrostatic actuator is used for purposes other than the droplet discharge head.

  A manufacturing process for forming the air opening hole 51 and the hydrophobic agent holding portion 52 of the electrostatic actuator of the droplet discharge head 1c will be described with reference to the flowchart of FIG.

  The process up to forming the main part of the actuator substrate 10 and sealing the second open hole is the same as the manufacturing process of the electrostatic actuator of the droplet discharge head 1 (steps S21 to S27). Then, after installing an absorber and injecting and sealing the liquid hydrophobic agent, the liquid chamber substrate 30 and the actuator substrate 10 are bonded together (steps S28 to S30). In this case, especially in the configuration in which the second open hole 51b is not sealed with the sealing agent 54a, the hydrophobic agent is supplied again from the hydrophobic agent holding portion after the hydrophobic treatment in the gap, so that even if it falls out of the gap. Although it does not become a big problem, since it is necessary to avoid that a water | moisture content penetrates into the space | gap 15a, it was set as such a process. Of course, the storage and process environment may be controlled so that the absorber installation, the liquid hydrophobic agent injection, and the sealing may be performed after the liquid hydrophobic substrate is injected after the liquid chamber substrate 30 and the actuator substrate 10 are bonded together.

  Next, with respect to the fifth droplet discharge head 1d, an exploded perspective view showing component configurations of the nozzle substrate, the liquid chamber substrate, and the actuator substrate of FIG. 34, and a perspective state plane arrangement of the nozzle substrate, the liquid chamber substrate, and the actuator substrate of FIG. 36, the X51-X51 cross section of FIG. 35 shown in FIG. 36, the X52-X52 cross section of FIG. 35 shown in FIG. 37, the X53-X53 cross section of FIG. 35 shown in FIG. 35, and a partially enlarged plan view around the liquid hydrophobic agent holding part in FIG. 40.

  The electrostatic actuator of the droplet discharge head 1 d has a liquid hydrophobic agent holding part 52 formed on the actuator substrate 10. The liquid hydrophobic agent holding part 52 is formed on the side closer to the gap 15a than the first atmosphere opening hole 51a and the second atmosphere opening hole 51b. Note that various arrangements may be adopted for this arrangement example.

  The hydrophobic agent holding portion 52 is formed by etching the sacrificial layer for forming the gap 15a and the lower electrode layer for increasing the cross-sectional area, like the communication path 53. If there is no need to increase the cross-sectional area, the sacrificial layer alone may be used. In the case where the gap 15a is formed by bonding the concave portion formed in the electrode substrate and the diaphragm forming substrate, the hydrophobic agent holding portion 52 and the communication path 53 can be formed in the same manner as the gap 15a.

  In addition, as shown in FIG. 40, the hydrophobic agent holding part 52 that holds the liquid hydrophobic agent has a structure in which the surface area is increased by, for example, bundling a plurality of fine tubes 521, and a structure that holds the liquid hydrophobic agent by capillary force. The void side 522 of the hydrophobic agent holding part 52 is preferably meandered so that the liquid hydrophobic agent does not flow into the void 15a. In this way, when the hydrophobic agent holding part 52 that holds the liquid hydrophobic agent is configured and the hydrophobic agent is difficult to be introduced in the intracavity hydrophobization step, the open hole 51 may be formed in parallel with the hydrophobic agent holding part 52.

  As shown in the flowchart of FIG. 41, the manufacturing process of the electrostatic actuator is substantially the same as the manufacturing process of the droplet discharge head 1, but after the hydrophobization process in the gap (steps S31 to S36), The liquid hydrophobic agent is injected into the liquid hydrophobic agent holding part 52 through the second opening hole 51b, and then the second opening hole 51b is sealed (steps S37 and S38). As described above, since the liquid hydrophobic agent can be injected and sealed immediately after the hydrophobization treatment in the void, it is easy to prevent moisture from entering the void after the hydrophobic treatment.

  Next, an example of an ink jet recording apparatus on which the droplet discharge head 1 is mounted will be described with reference to a perspective view of FIG. 42 and a side view showing a configuration of a mechanism portion of FIG. The ink jet recording apparatus 90 includes a carriage 98 movable in the main scanning direction inside the apparatus main body, a droplet discharge head 1 mounted on the carriage 98, an ink cartridge 99 for supplying ink to the droplet discharge head 1, and the like. A paper feed cassette (or a paper feed tray) 93 on which a large number of sheets 92 can be stacked from the front side is detachably attached to the lower part of the apparatus main body. Further, it has a manual feed tray 94 that is opened to manually feed the paper 92, takes in the paper 92 fed from the paper feed cassette 93 or the manual feed tray 94, and records a required image by the printing mechanism 91. Thereafter, the paper is discharged onto a paper discharge tray 95 mounted on the rear side.

  The printing mechanism 91 holds a carriage 98 slidably in the main scanning direction by a main guide rod 96 and a sub guide rod 97 which are guide members horizontally mounted on left and right side plates (not shown). A droplet discharge head 1 that discharges ink droplets of each color (Y), cyan (C), magenta (M), and black (Bk) is arranged in a direction intersecting the main scanning direction with a plurality of ink discharge ports (nozzles). However, it is mounted with the ink droplet ejection direction facing downward. Further, each ink cartridge 99 for supplying ink of each color to the droplet discharge head 1 is replaceably mounted on the carriage 98.

  The ink cartridge 99 is provided with an air port communicating with the atmosphere at the upper side, and a supply port for supplying ink to the droplet discharge head 1 at the lower side, and has a porous body filled with ink inside. The ink supplied to the droplet discharge head 1 is maintained at a slight negative pressure by the capillary force of the material. In addition, although the droplet discharge head 1 of each color is used as the droplet discharge head 1, a single liquid chamber discharge head having nozzles for discharging ink droplets of each color may be used.

  Here, the carriage 98 is slidably fitted to the main guide rod 96 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the secondary guide rod 97 on the front side (upstream side in the paper conveyance direction). is doing. In order to move and scan the carriage 98 in the main scanning direction, a timing belt 104 is stretched between the driving pulley 102 and the driven pulley 103 that are rotationally driven by the main scanning motor 101, and the timing belt 104 is moved to the carriage 98. The carriage 98 is reciprocally driven by forward and reverse rotations of the main scanning motor 101.

  On the other hand, in order to convey the paper 92 set in the paper feed cassette 93 to the lower side of the droplet discharge head 1, the paper feed roller 105 and the friction pad 106 for separating and feeding the paper 92 from the paper feed cassette 93, and the paper 92 A guide member 107 that guides the sheet 92, a conveying roller 108 that reverses and conveys the fed paper 92, a conveying roller 109 that is pressed against the peripheral surface of the conveying roller 108, and a feeding angle of the sheet 92 from the conveying roller 108. And a tip roller 110 for defining. The transport roller 108 is rotationally driven through a gear train by a sub-scanning motor.

  Then, a printing receiving member 111 which is a paper guide member is provided to guide the paper 92 sent from the transport roller 108 corresponding to the movement range of the carriage 98 in the main scanning direction on the lower side of the droplet discharge head 1. Yes. A conveyance roller 112 and a spur 113 that are rotationally driven to send the paper 92 in the paper discharge direction are provided on the downstream side of the printing receiving member 111 in the paper conveyance direction, and the paper 92 is further discharged to the paper discharge tray 95. A roller 114, a spur 115, and guide members 116 and 117 that form a paper discharge path are disposed.

  When recording with the inkjet recording apparatus 90, the droplet discharge head 1 is driven in accordance with the image signal while moving the carriage 98, thereby discharging ink onto the stopped sheet 92 to record one line. Thereafter, after the sheet 92 is conveyed by a predetermined amount, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the paper 92 reaches the recording area, the recording operation is terminated and the paper 92 is discharged.

  Further, a recovery device 117 for recovering the ejection failure of the droplet ejection head 1 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 98. The recovery device 117 includes a cap unit, a suction unit, and a cleaning unit. During printing standby, the carriage 98 is moved to the recovery device 117 side, and the droplet discharge head 1 is capped by the capping unit to keep the discharge port portion in a wet state, thereby preventing discharge failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  In addition, when a discharge failure occurs, the discharge port (nozzle) of the droplet discharge head 1 is sealed with a capping unit, and bubbles and the like are sucked out from the discharge port with a suction unit through the tube, and adhere to the discharge port surface. The discharged ink, dust, etc. are removed by the cleaning means, and the ejection failure is recovered. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  As described above, since the ink jet recording apparatus 90 is equipped with the liquid droplet ejection head 1 having the electrostatic actuator, there is no ink droplet ejection failure due to vibration plate drive failure and stable ink droplet ejection characteristics. As a result, the image quality is improved. In addition, since a head that can be driven at a low voltage is mounted, the power consumption of the entire inkjet recording apparatus can be reduced.

  In the above description, the case where the droplet discharge head 1 is used in the ink jet recording apparatus 90 has been described. However, even if the droplet discharge head 1 is applied to a device that discharges droplets other than ink, for example, a liquid resist for patterning. good.

1 is an exploded perspective view showing a configuration of a droplet discharge head of the present invention. FIG. 3 is a plan layout view showing a configuration of a droplet discharge head. It is X11-X11 sectional drawing of FIG. It is X12-X12 sectional drawing of FIG. It is X13-X13 sectional drawing of FIG. It is Y11-Y11 sectional drawing of FIG. It is Y12-Y12 sectional drawing of FIG. It is Y13-Y13 sectional drawing of FIG. It is an enlarged view around the opening hole of an actuator substrate. It is an arrangement drawing showing the 2nd composition of the opening hole of an actuator substrate, and a hydrophobic agent maintenance part. It is an arrangement drawing showing the 3rd composition of the opening hole of an actuator substrate, and a hydrophobic agent maintenance part. It is an arrangement drawing showing the 4th composition of the opening hole of an actuator substrate, and a hydrophobic agent maintenance part. FIG. 10 is a layout diagram illustrating a fifth configuration of the opening hole and the hydrophobic agent holding portion of the actuator substrate. It is a flowchart which shows the manufacturing process which forms the 1st and 2nd air | atmosphere open hole and a hydrophobic agent holding | maintenance part, and seals a hydrophobic agent. It is process drawing which shows the manufacturing process which forms a 1st and 2nd air | atmosphere open hole and a hydrophobic agent holding | maintenance part, and seals a hydrophobic agent. It is a layout diagram showing the layout of the first and second atmosphere opening holes and the communication path. It is a layout diagram showing the second layout of the first and second atmosphere opening holes and the communication path. It is a layout diagram showing a third layout of the first and second atmosphere opening holes and the communication path. It is a layout diagram showing a fourth layout of the first and second atmosphere opening holes and the communication path. It is a disassembled perspective view which shows the structure of a 2nd droplet discharge head. FIG. 6 is a plan view showing a configuration of a second droplet discharge head. It is Y21-Y21 sectional drawing of FIG. It is a flowchart which shows the manufacturing process which forms the air release hole and hydrophobic agent holding | maintenance part of a 2nd droplet discharge head, and seals a hydrophobic agent. It is process drawing which shows the manufacturing process which forms the atmospheric | air release hole and hydrophobic agent holding | maintenance part of a 2nd droplet discharge head, and seals a hydrophobic agent. It is sectional drawing which shows the structure of the hydrophobic agent holding | maintenance part in a 3rd droplet discharge unit. It is sectional drawing which shows the 2nd structure of the hydrophobic agent holding | maintenance part in a 3rd droplet discharge unit. It is sectional drawing which shows the 3rd structure of the hydrophobic agent holding | maintenance part in a 3rd droplet discharge unit. It is a disassembled perspective view which shows the structure of a 4th droplet discharge head. FIG. 10 is a plan layout view showing a configuration of a fourth droplet discharge head. It is X41-X41 sectional drawing of FIG. It is Y42-Y42 sectional drawing of FIG. It is sectional drawing which shows the part of the 1st and 2nd open hole in a 4th droplet discharge unit. It is a flowchart which shows the manufacturing process which forms the air release hole and hydrophobic agent holding | maintenance part of a 4th droplet discharge head. It is a disassembled perspective view which shows the structure of a 5th droplet discharge head. FIG. 10 is a plan layout view showing a configuration of a fifth droplet discharge head. It is X51-X51 sectional drawing of FIG. It is X52-X52 sectional drawing of FIG. It is X53-X53 sectional drawing of FIG. It is Y51-Y51 sectional drawing of FIG. FIG. 9 is an enlarged plan view showing a configuration around a liquid hydrophobic agent holding unit in a fifth droplet discharge head. It is a flowchart which shows the manufacturing process which forms the air | atmosphere open hole and hydrophobic agent holding | maintenance part of a 5th droplet discharge head, and seals a hydrophobic agent. It is a perspective view showing an ink jet recording apparatus equipped with a droplet discharge head. It is a side view which shows the structure of the mechanism part of an inkjet recording device.

Explanation of symbols

1; droplet discharge head, 10; actuator substrate, 11; silicon substrate,
12; substrate insulating film, 13; fixed electrode layer, 13a; fixed electrode, 14; fixed electrode side insulating film,
15a; gap, 20; diaphragm, 21; diaphragm side insulating film, 22; diaphragm electrode layer,
22a; diaphragm electrode, 30; liquid chamber substrate, 31; common liquid chamber, 32; fluid resistance portion,
33; pressurized liquid chamber, 34; communication pipe, 40; nozzle plate, 41; nozzle hole, 42;
51; Open hole, 51a; First open hole, 51b; Second open hole, 52; Hydrophobic agent holding part,
53; Communication path, 54; Sealant, 60; Liquid supply path, 90; Inkjet recording apparatus.

Claims (8)

When a deformable diaphragm having at least a part of a movable electrode and a fixed electrode disposed opposite to the diaphragm via a gap, when a voltage is applied between the movable electrode and the fixed electrode In the electrostatic actuator that deforms the diaphragm with the generated electrostatic force,
A communication passage communicating with the gap, an air release portion having an air release hole for communicating the communication passage with the outside, and a hydrophobic agent holding portion in contact with the communication passage, the diaphragm and the fixed electrode A hydrophobic film is formed on the surface of the void side, a vapor of a hydrophobic agent having a hydrophobic group is sealed in the void, and a liquid hydrophobic agent is held in the hydrophobic agent holding portion. Type actuator.   2. The electrostatic actuator according to claim 1, wherein a film that does not allow the liquid hydrophobic agent to pass but allows the hydrophobic agent vapor to pass is provided between the communication path communicating with the gap and the hydrophobic agent holding portion.   The electrostatic actuator according to claim 1, wherein an absorber is disposed in the hydrophobic agent holding portion, and the liquid hydrophobic agent is held in the absorber. When a deformable diaphragm having at least a part of a movable electrode and a fixed electrode disposed opposite to the diaphragm via a gap, when a voltage is applied between the movable electrode and the fixed electrode In the electrostatic actuator that deforms the diaphragm with the generated electrostatic force,
A communicating path communicating with the gap, and a hydrophobic agent holding portion provided between the communicating path and an atmosphere opening portion having an atmosphere opening hole, on the surface of the diaphragm and the fixed electrode on the gap side An electrostatic actuator, wherein a hydrophobic film is formed, a vapor of a hydrophobic agent having a hydrophobic group is sealed in the gap, and a liquid hydrophobic agent is held in the hydrophobic agent holding portion.   5. The electrostatic actuator according to claim 4, wherein the hydrophobic agent holding portion has a meandering shape on the communication path side so that liquid hydrophobic agent does not flow into the gap. A deformable diaphragm at least a part of which is a movable electrode, a fixed electrode opposed to the diaphragm via a gap, and formed on a surface of the diaphragm and the fixed electrode on the gap side A movable membrane having a hydrophobic membrane, a communication passage provided in communication with the air gap, an air release portion having an air release hole for communicating the communication passage with the outside, and a hydrophobic agent holding portion in contact with the communication passage; An electrostatic actuator manufacturing method for deforming the diaphragm with an electrostatic force generated when a voltage is applied between an electrode and the fixed electrode,
A method for manufacturing an electrostatic actuator, comprising: sealing a vapor of a hydrophobic agent having a hydrophobic group in the gap, and then injecting a liquid hydrophobic agent into the hydrophobic agent holding portion.   7. The electrostatic actuator according to claim 1, wherein the diaphragm is deformed by an electrostatic force generated when a voltage is applied between the movable electrode and the fixed electrode, and droplets are discharged from the nozzle. A liquid droplet discharge head characterized by discharging liquid.   An image forming apparatus comprising: the droplet discharge head according to claim 7, wherein an image is recorded by discharging an ink droplet from a nozzle of the droplet discharge head.

Images