JP2001270105A - Liquid drop discharge head, ink jet recorder and microactuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge head which can be particularly highly densely arranged in terms of a thickness and a flatness of a diaphragm, an ink jet recorder which can record at high speeds with a high density, and a microactuator which can be highly densely formed in order to thin the diaphragm according to requirements of a high speed, a high density and a low voltage in a piezoelectric type or an electrostatic type ink jet head which discharges ink drops by deforming and displacing the diaphragm and to maintain a highly accurate flatness of the diaphragm without deflecting and waving the diaphragm to enable efficient driving with a gap between the diaphragm and an electrode narrowed particularly in the electrostatic type ink jet head. SOLUTION: The diaphragm 42 is formed of a silicon nitride film 81 having tensile stress property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a droplet discharge head, an ink jet recording apparatus and a microactuator.

[0002]

2. Description of the Related Art In general, an ink jet head, which is a liquid droplet ejection head including a microactuator used in an ink jet recording apparatus used as an image recording apparatus (image forming apparatus) such as a printer, a facsimile, a copying apparatus, and a plotter, discharges ink droplets. A nozzle for discharging, an ink flow path (also referred to as a pressure chamber, a pressure chamber, a pressurized liquid chamber, a liquid chamber, a discharge chamber, etc.) communicating with the nozzle, and pressurizing the ink in the ink flow path. A pressure generating means (actuator means) is provided, and the ink in the ink flow path is pressurized by driving the pressure generating means to eject ink droplets from the nozzles.

[0003] Conventional ink jet heads are of the piezo type, in which the walls of the pressurizing chamber are formed using piezoelectric elements and the diaphragm is deformed and displaced to discharge ink droplets in terms of the type of pressure generating means. A bubble type in which a bubble is generated by ink film boiling using a heating resistor disposed in a pressurized chamber to discharge ink droplets, and a diaphragm (or an electrode integrated therewith) which forms a wall surface of the pressurized chamber ) And an electrostatic type in which an ink droplet is ejected by deforming and displacing the diaphragm with electrostatic force using an electrode.

[0004] Further, in the case of conventional ink jet heads, especially in the piezo type and the electrostatic type, from the viewpoint of the direction of ejection of ink droplets, JP-A-6-8449, JP-A-6-23986, and the like. As described in
An edge shooter method in which ink droplets are ejected in a direction orthogonal to the direction of displacement of the diaphragm, and an ink jet in the direction of displacement of the diaphragm as described in JP-A-9-314837 and JP-A-10-304865. It is broadly divided into a side shooter method that discharges droplets.

In the above-described piezo-type or electrostatic-type ink jet head using a diaphragm, the diaphragm is required to be made thinner and more precise in accordance with the demand for higher speed, higher density, or lower voltage. As the film becomes thinner, it is important to ensure the thickness (rigidity) of the vibration plate and the ink contact property (elution resistance to ink). In addition, a diaphragm and an electromechanical transducer for deforming and displacing the diaphragm,
Alternatively, a portion composed of the diaphragm and the electrode facing the diaphragm is referred to as a microactuator. Further, the microactuator is not limited to the head, but may be used for a micropump or the like. Here, the head will be described.

Therefore, in the conventional ink jet head, Japanese Patent Application Laid-Open Nos. Hei 6-23986 and Hei 6-71
As described in Japanese Patent Application Laid-Open No. 882 or Japanese Patent Application Laid-Open No. 9-267479, a high-concentration boron diffusion layer in which boron is diffused is formed on a silicon substrate forming a diaphragm, and this silicon substrate is anisotropically etched. As a result, the etching is stopped at the high concentration boron diffusion layer,
A diaphragm made of a high-concentration boron diffusion layer is formed. In addition, by stopping the etching using the silicon oxide film as an etching stop layer, a diaphragm using an SOI substrate or a SIMOX substrate can be formed.

[0007]

The conventional piezoelectric or electrostatic ink jet head has a discharge density of about 200 dpi or less, and the recording density is increased by increasing the number of passes (the number of head scans) using this head. The recording density is set to about 1200 dpi. However, since the ejection density of the head itself is low, to increase the recording density, the number of passes increases and the recording speed decreases.

Therefore, the ejection density of the head itself is set to 300 d
By increasing it to more than pi, the recording speed can be increased,
The pitch between adjacent channels (between bits) is 85 μm in order to make the ejection density of the head itself 300 dpi or more.
About. Therefore, the width of the diaphragm for discharge must be narrowed, but in order to narrow the width of the diaphragm and obtain stable discharge characteristics at a desired low voltage, the thickness of the diaphragm must be reduced. In particular, in the case of an electrostatic ink jet head, the gap between the diaphragm and the electrode must be reduced as much as possible to drive as efficiently as possible.

As described above, when the thickness of the diaphragm is reduced,
As a result, it is easily damaged by tears and the like, and also easily damaged by elution into the ink. Further, in order to maintain a small gap, it is necessary to maintain high-precision flatness without slack or waving. In addition, in order to mass-produce the head, it is necessary to stably produce a thin diaphragm capable of maintaining high-precision flatness with a high yield.

However, when the diaphragm is formed by the high-concentration boron diffusion layer used in the above-mentioned conventional electrostatic ink-jet head, the diaphragm has a thickness of 1.5 μm.
When it exceeds m, it is suitable for mass production. However, a diaphragm having a thickness of 1.5 μm or less, particularly 1.0 μm to 0.3 μm, is formed stably at a low cost while suppressing variations in the plate thickness and with high plane accuracy. It is extremely difficult.

As described above, in the conventional droplet discharge head, the density and the flatness of the diaphragm are particularly high (300
(dpi or more) cannot be obtained at a low cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides a droplet discharge head capable of high density, an ink jet recording apparatus capable of high speed and high density recording, and a microactuator capable of high density. The purpose is to provide.

[0013]

In order to solve the above-mentioned problems, a droplet discharge head according to the present invention is configured such that a diaphragm is made of an insulating film having tensile stress.
In this specification, the “diaphragm” means a deformable region. Here, the insulating film is preferably a silicon nitride film. Further, it is preferable to have an electrode film on the surface of the diaphragm.

In the droplet discharge head according to the present invention, the vibration plate is formed of a laminated film of insulating films, and has a structure having tensile stress as a whole. Here, it is preferable that the film forming the laminated film includes a silicon nitride film. Further, it is preferable that the film forming the laminated film includes a silicon oxide film. Further, it is preferable to have an electrode film on the surface or inside of the laminated film.

When an electrode film is provided, the electrode film may be separated for each bit.

In the droplet discharge head according to the present invention, the diaphragm is made of a conductive film having tensile stress. Here, the conductive film is preferably a titanium nitride film, a high-temperature metal film, or a polysilicon film.

The droplet discharge head according to the present invention has a configuration in which the diaphragm is made of a laminated film of conductive films and has tensile stress as a whole. Here, the film forming the stacked film preferably includes a titanium nitride film, a high-temperature metal film, or a polysilicon film.

In the droplet discharge head according to the present invention, the diaphragm is made of a laminated film of an insulating film and a conductive film, and has a structure having tensile stress as a whole. Here, it is preferable that the film forming the laminated film includes a silicon nitride film. Further, it is preferable that the film forming the laminated film includes a silicon oxide film. Further, it is preferable that the film forming the laminated film includes a titanium nitride film, a high-temperature metal film, or a polysilicon film.

In the droplet discharge head according to the present invention, the diaphragm is a laminated film of a film having a tensile stress property and a film having a compressive stress property, and has a structure having a tensile stress property as a whole. Here, the tensile stress film may be an insulating film, a stacked film of insulating films, a conductive film, a stacked film of conductive films, or a stacked film of an insulating film and a conductive film.
In this case, the compressive stress film is preferably an insulating film. Preferably, the diaphragm is a laminated film of a silicon nitride film and a silicon oxide film. Further, it is preferable that the diaphragm is a titanium nitride film, a high-temperature metal film, a polysilicon film, or a laminated film of a film of a combination of two or more thereof and a silicon oxide film.

Each of the droplet discharge heads according to the present invention has a
Especially effective when the output density is 300 dpi or more.
You. Further, the tensile stress of the diaphragm is 1E + 11 (dyne
/ Cm ^Two) Is preferably not exceeded. In addition, "1E +
11 ”is“ 1 × 10¹¹Has the same meaning as In addition,
High-concentration boron diffused into silicon on the channel side surface of the moving plate
It preferably has a higher liquid contact property than the layer. Further
In addition, the diaphragm has a thickness of 0.3 μm to 1.5 μm.
It must be within the range having the same rigidity as the recon diaphragm
preferable.

Further, each of the droplet discharge heads according to the present invention has an electrode facing the diaphragm, and can be configured to discharge droplets by displacing the diaphragm with electrostatic force. Alternatively, an electromechanical transducer that deforms the diaphragm may be provided, and the diaphragm may be displaced by the displacement of the electromechanical transducer to discharge droplets.

The ink jet recording apparatus according to the present invention comprises:
An ink jet head having a nozzle for discharging ink droplets, an ink flow path communicating with the nozzle, and pressure generating means for pressurizing ink in the ink flow path is configured to be a droplet discharge head according to the present invention. Things.

The microactuator according to the present invention comprises:
A diaphragm, and a driving unit for deforming the diaphragm,
The diaphragm has a configuration having tensile stress properties as a whole. Here, the diaphragm is an insulating film, a laminated film of insulating films,
A conductive film, a stacked film of conductive films, or a stacked film of an insulating film and a conductive film can be used.

The microactuator according to the present invention comprises:
A diaphragm, and a driving unit for deforming the diaphragm,
The diaphragm is a laminated film of a tensile stress film and a compressive stress film, and has a structure having tensile stress as a whole.

In the microactuator according to the present invention, the diaphragm has a tensile stress of 1E + 11 (dyne / cm).
It is preferable not to exceed ² ). Further, it is preferable that the thickness of the diaphragm is within a range having a rigidity equivalent to that of a silicon diaphragm having a thickness of 0.3 μm to 1.5 μm. Further, it is preferable that an electrode facing the diaphragm is provided, and the diaphragm is displaced by electrostatic force.

[0026]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic perspective explanatory view of a mechanism of an ink jet recording apparatus according to the present invention, and FIG. 2 is a side explanatory view of the mechanism.

This ink jet recording apparatus includes a carriage movable in the main scanning direction inside the recording apparatus main body 1, a recording head including an ink jet head mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. A paper feed cassette (or a paper feed tray) 4 capable of loading a large number of sheets 3 from the front side is detachably attached to a lower portion of the apparatus main body 1. In addition, the manual tray 5 for manually feeding the paper 3 can be opened, and the paper 3 fed from the paper feed cassette 4 or the manual tray 5 is taken in. After recording the image, the sheet is discharged to the sheet discharge tray 6 mounted on the rear side.

The printing mechanism 2 slides the carriage 13 in the main scanning direction (the direction perpendicular to the paper surface in FIG. 2) by a main guide rod 11 and a sub guide rod 12 which are guide members which are horizontally mounted on left and right side plates (not shown). This carriage 1
Reference numeral 3 denotes a head 14 which is an ink-jet head which is a liquid-jet head according to the present invention which discharges ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). The ink tank (ink cartridge) 15 for supplying ink of each color to the head 14 is exchangeably mounted on the upper side of the carriage 13.

Here, the carriage 13 is slidably fitted to the main guide rod 11 on the rear side (downstream side in the paper transport direction), and the front side (downstream side in the paper transport direction) of the slave guide rod 1.
2 slidably mounted. The main scanning motor 1 is moved to scan the carriage 13 in the main scanning direction.
A timing belt 20 is stretched between a driving pulley 18 and a driven pulley 19, which are driven to rotate by 7, and the timing belt 20 is fixed to the carriage 13. Further, although the heads 14 of each color are used here as the recording head, a single head having nozzles for ejecting ink droplets of each color may be used.

On the other hand, the paper 3 set in the paper feed cassette 4
Roller 21 and a friction pad 22 for separating and feeding the paper 3 from the paper feed cassette 4 and a guide member 23 for guiding the paper 3
A transport roller 24 that reverses and transports the fed paper 3, a transport roller 25 that is pressed against the peripheral surface of the transport roller 24, and a tip roller 26 that defines an angle at which the paper 3 is fed from the transport roller 24. Is provided. The transport roller 24 is driven to rotate by a sub-scanning motor 27 via a gear train.

A print receiving member 29 is provided as a paper guide member for guiding the paper 3 fed from the transport roller 24 below the recording head 14 in accordance with the moving range of the carriage 13 in the main scanning direction. I have. On the downstream side of the printing receiving member 29 in the sheet conveying direction, a conveying roller 31 and a spur 32, which are driven to rotate in order to send out the sheet 3 in the sheet discharging direction.
And a paper discharge roller 33 and a spur 34 for feeding the paper 3 to the paper discharge tray 6 and guide members 35 and 36 for forming a paper discharge path.

A reliability maintenance / recovery mechanism (hereinafter referred to as a "subsystem") 37 for maintaining and recovering the reliability of the head 14 is disposed on the right end side in the moving direction of the carriage 13. The carriage 13 is moved to the subsystem 37 side during printing standby, and the head 14 is capped by capping means or the like.

Next, the ink jet head according to the first embodiment of the present invention including the microactuator according to the present invention, which constitutes the head 14 of the ink jet recording apparatus, will be described with reference to FIGS. 3 is an exploded perspective view of the head, FIG. 4 is a cross-sectional view of the head in the longitudinal direction of the diaphragm, FIG. 5 is an enlarged view of a main part of FIG. 4, and FIG. 7 is an enlarged sectional explanatory view of FIG.
FIG. 3 is an explanatory plan view of a main part showing the head in a transmission state.

The ink jet head 40 is provided on a flow path substrate (also referred to as a liquid chamber substrate or a first substrate) 41 using a silicon substrate such as a single crystal silicon substrate or an SOI substrate, and provided on the lower surface of the flow path substrate 41. A vibrating plate 42, a silicon substrate provided below the flow path substrate 41 via the vibrating plate 42,
An electrode substrate 43 using a Pyrex (registered trademark) glass substrate, a ceramic substrate, or the like, and a nozzle plate 44 provided above the flow path substrate 41 are provided. A pressurizing chamber 46 serving as an ink flow path, and a common liquid chamber 48 communicating with each pressurizing chamber 46 via a fluid resistance part 47 also serving as an ink supply path are formed.

A pressure chamber 46, which is a plurality of liquid flow paths to which a nozzle 45 communicates, and a vibration plate 42 serving as a bottom surface of the pressure chamber 46 are formed in the flow path substrate 41. A groove for forming a common liquid chamber 48 is formed in the channel substrate 41 and the electrode substrate 43.

Here, the diaphragm 42 forming the wall surface of the pressurizing chamber 46, which is a liquid flow path, has tensile stress as a whole. The thickness of the diaphragm 42 is 300 d in this case.
In order to obtain a pi-shaped nozzle pitch (discharge density), the nozzle pitch is set to 0.
It has an arbitrary value selected from the range of 3 μm to 1.5 μm. Further, the tensile stress of the entire diaphragm 42 is set to 1E + 11 (dyne / cm 2) so as not to cause breakage due to the stress.
² ) It should be within the value not exceeding. Note that "1
“E + 11” means “1 × 10 ¹¹ ”.

The diaphragm 42 may have a single-layer structure or a multi-layer structure. When the vibration plate 42 has a multi-layer structure, it can be a laminated film of a tensile stress film and a compressive stress film. Film, conductive film, laminated film of insulating film, laminated film of conductive film,
Any of a stacked film of an insulating film and a conductive film may be used.

Here, a silicon nitride film (tensile stress) as an insulating film, a silicon nitride film and a silicon nitride film as a laminated film of an insulating film which is also a laminated film of a tensile stress film and a compressive stress film. An oxide film (compressive stress) or a laminate of a silicon nitride film and boron glass (compressive stress) can be given. Examples of the conductive film or the laminated film of the conductive film include a titanium nitride (TiN) film, a polysilicon film, a high-temperature metal film such as Ti, W, and Mo, and a combination of these films. Further, as a laminated film of an insulating film and a conductive film which is also a laminated film of a tensile stress film and a compressive stress film, the above-mentioned silicon nitride film, silicon oxide film, boron glass, titanium nitride (Ti
N) films, polysilicon films, or combinations of high-temperature metal films such as Ti, W, and Mo.

When an insulating film or a laminated film of insulating films is used for the diaphragm 42, an electrode film is formed on the surface or inside (between the laminated films) of the diaphragm 42. As the electrode film, use is made of titanium nitride (TiN), polysilicon, or a high-temperature metal film of Ti, W, Mo, or the like, which is used as the above-described conductive film (not limited to one having a tensile stress property). Can be.

A silicon oxide film (layer) 43a is formed on the electrode substrate 43, a concave portion 54 is formed in the portion of the oxide film 43a, and an electrode 55 facing the diaphragm 42 is provided on the bottom surface of the concave portion 54. A gap 56 of about 1.0 μm or less is formed between the diaphragm 42 and the electrode 55, and the diaphragm 42 and the electrode 55 constitute a microactuator according to the present invention.

Here, as shown in FIG. 4, the concave portion 54 of the electrode substrate 43 has a cross-sectional shape having an inclined surface in the transverse direction of the diaphragm, and an electrode 55 is formed on the bottom surface of the concave portion 54 to form The diaphragm 42 and the electrode 55 are opposed to each other in a non-parallel state in the short direction of the diaphragm. The gap 56 formed between the non-parallel diaphragm 42 and the electrode 55 is referred to as a non-parallel gap. Of course, the diaphragm 42
The electrode 55 and the electrode 55 can be opposed to each other in a parallel state, or can be a non-parallel gap in the longitudinal direction of the diaphragm.

The electrode 55 is provided as a connecting portion (electrode take-out portion) 55a which extends to the outside and is connected to a connecting means connected to an external driving circuit. An electrode protection film 57 made of an oxide-based insulating film such as a SiO ₂ film or a nitride-based insulating film such as a Si ₃ N ₄ film is formed on the surface of the electrode 55. Instead of forming the film 57, an insulating film can be formed on the diaphragm 42 side.

When a single crystal silicon substrate is used as the electrode substrate 43, a normal silicon wafer can be used. The thickness varies depending on the diameter of the silicon wafer, but in the case of a 4-inch diameter silicon wafer, the thickness is about 500 μm, and in the case of a 6-inch diameter silicon wafer, the thickness is often about 600 μm. When a material other than the silicon wafer is selected, the smaller the difference in thermal expansion coefficient from silicon of the flow path substrate, the more the reliability can be improved when bonding to the diaphragm.

The bonding between the vibration plate 42 of the flow path substrate 41 and the electrode substrate 43 is performed in order to secure the gap 56 with high accuracy, so that a more reliable physical connection, for example, the electrode substrate 43 is formed of silicon. In this case, bonding is performed using a direct bonding method via an oxide film. This direct bonding is 500-12
It is carried out at a high temperature of about 00 ° C. In the direct bonding of silicon, the higher the temperature, the higher the bonding strength, and it is difficult to generate voids (poor bonding) at the bonding surface, so that in this respect, the vibration plate 42 has a silicon nitride film or a silicon nitride film and an oxide film. Is preferably used. In particular, by using a silicon nitride film or a laminated film of a silicon nitride film and an oxide film, the ink contact property with the alkaline ink is excellent, so that long-term stable driving can be performed.

When a glass such as Pyrex (borosilicate glass) is used as the electrode substrate 43, anodic bonding can be performed. When the electrode substrate 43 is formed of silicon and anodic bonding is performed, the electrode substrate 43 and the diaphragm 4
Pyrex glass may be formed between the first and second films, and anodic bonding may be performed via this film. Further, the vibration plate 42 and the electrode substrate 43 can be bonded by eutectic bonding in which a binder such as gold is interposed between bonding surfaces using a silicon substrate.

The electrode 55 of the electrode substrate 43 is
A commonly used in the process of forming a semiconductor element
Metal materials such as l, Cr, and Ni, high melting point metals such as Ti, TiN, and W, and polycrystalline silicon materials whose resistance has been reduced by impurities can be used. When the electrode substrate 43 is formed of a silicon wafer, it is necessary to form an insulating layer (the above-described oxide film layer 43a) between the electrode substrate 43 and the electrode 55. When an insulating material such as a glass substrate or a ceramic substrate is used for the electrode substrate 43, it is not necessary to form an insulating layer between the electrode substrate 43 and the electrode 55.

When a silicon substrate is used as the electrode substrate 43, an impurity diffusion region can be used as the electrode 55. In this case, the impurity used for diffusion is an impurity having a conductivity type opposite to the conductivity type of the substrate silicon, a pn junction is formed around the diffusion region, and the electrode 55 and the electrode substrate 43 are formed.
Are electrically insulated from each other.

The nozzle plate 44 has a number of nozzles 45 formed thereon. The pitch of the nozzles 45 is 30 in terms of ejection density.
0 dpi. Further, the nozzle plate 44 has a groove for forming a fluid resistance part 47 for communicating the common liquid chamber 48 and the pressure chamber 46. Here, the nozzle plate 44 may be formed by Ni electroforming, SUS, or a multilayer structure of a polymer resin layer and a metal layer.

The nozzle plate 44 is formed larger than the electrode substrate 42 so that a part of the nozzle plate 44 covers the electrode extraction portion 55a of the actuator member. By thus making the nozzle plate 44 larger than the actuator member, the nozzle plate 43 can completely cover the electrode lead-out portion 55a of the actuator member, and the ink staying on the nozzle plate 44 is removed from the electrode lead-out portion 55a. Intrusion into the part can be reliably prevented.

In the ink jet head 40, the nozzles 44 are arranged in two rows, and the pressurizing chamber 46, the vibration plate 42, the electrodes 55 and the like are arranged in two rows corresponding to the nozzles 44, respectively. A configuration is adopted in which a common liquid chamber 48 is disposed in the (center portion), and ink is distributed from the common liquid chamber 48 to the left and right pressurizing chambers 46 and supplied. Thereby, the ink supply to each pressurizing chamber 46 can be evenly distributed,
With almost no buffering of the driving state of each pressurizing chamber,
Uniform ink droplet ejection characteristics can be ensured, and a multi-nozzle head having a large number of nozzles can be configured with a simple head configuration.

Then, an FPC cable 61 in which a driver IC (driving IC chip) 60 as a head driving circuit is mounted by wire bonding on an electrode take-out portion 55a continuous with the electrode 55 of the ink jet head 40 is formed of an anisotropic conductive film or the like. Connected through. At this time, the electrode substrate 4
As shown in FIGS. 4 and 5, gap sealing using an adhesive such as epoxy resin is performed between the electrode extraction portion 55a and the nozzle plate 44, including the space between the nozzle plate 3 and the nozzle plate 44 (the entrance of the gap 56). The diaphragm 62 is hermetically sealed to prevent moisture from entering the gap 56 and preventing the diaphragm 42 from being displaced.

Further, the electrode substrate 43 and the nozzle plate 44 are joined on the frame member 65 with an adhesive. Also,
The end of the nozzle plate 44 and the frame member 65 are sealed and joined with a gap sealing agent 68 using an adhesive such as epoxy resin, and the ink on the surface of the nozzle plate 44 having water repellency is applied to the electrode substrate 43 or the like. It is prevented from wrapping around the FPC cable 61 and the like.

The frame member 65 has an ink supply hole 66 for supplying ink from the outside to the common liquid chamber 48 of the ink jet head 40. The FPC cable 61 and the like have holes formed in the frame member 65. 67.

The frame member 6 of the head 14
5 includes a joint member 70 with the ink cartridge 15.
Are connected, and ink is supplied from the ink cartridge 15 to the common liquid chamber 48 through the ink supply hole 66 via the filter 71 thermally fused to the frame member 65.

In the ink-jet head 40, the diaphragm 42 is used as a common electrode, the electrode 55 is used as an individual electrode, and a driving waveform (driving voltage) is applied between the diaphragm 42 and the electrode 55, whereby the diaphragm 42 is used. The diaphragm 42 is deformed and displaced toward the electrode 55 due to an electrostatic force generated between the diaphragm 55 and the electrode 55, and the diaphragm 42 is returned and deformed by discharging electric charges between the diaphragm 42 and the electrode 55 from this state, When the internal volume (volume) / pressure of the pressurizing chamber 46 changes, ink droplets are ejected from the nozzle 45.

Since the vibration plate 42 of the ink-jet head 40 has tensile stress as a whole, it does not deform when there is no load (in a state where no driving waveform is applied), and the small gap (0. (About 5 μm) can be stably secured, and the thickness of the diaphragm 42 can be reduced (thickness having a rigidity corresponding to a silicon diaphragm having a thickness of 0.3 to 1.5 μm). Even if the discharge density is 300 dpi or more, sufficient discharge characteristics can be obtained at a low voltage. As a result, a discharge density of 300
A high density head of dpi or more can be obtained.

On the other hand, as shown in FIG. 8, when a thin film is formed by using a conventionally used compressive stress diaphragm 72, the diaphragm 72 remains on the diaphragm 72 'even when no drive waveform is applied. As shown in the figure, it is deformed to either the discharge chamber side or the electrode substrate side, making it difficult to maintain a small gap. In addition, since the steady state of the diaphragm 72 is not constant, the discharge characteristics between the channels are reduced. Variations will occur.

In a conventional silicon vibration plate (solid vibration plate) formed by leaving a part of the silicon substrate, if the surface is oxidized for the purpose of obtaining ink resistance or the like, if the oxide film is thick, it is deformed. I'm sure it will. For example, 2
When an oxide film of about 0.2 μm is formed on a silicon plate of μm, bending of about 0.02 to 0.2 μm occurs. This bending amount is a fatal deformation amount when an actuator having a gap length of 1 μm or less is formed. In the case of a conventional silicon diaphragm formed by leaving a part of a silicon substrate, it is extremely difficult to form a thickness of about 1.5 μm or less with good controllability, and the whole diaphragm has a compressive stress property. With a complicated configuration (deflection problem), its realization becomes more difficult.

Next, an ink jet head according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 9 is an explanatory plan view of the head, FIG. 10 is an explanatory sectional view in the longitudinal direction of the diaphragm along the line AA in FIG.
FIG. 1 is an explanatory cross-sectional view of the diaphragm in the lateral direction along the line BB in FIG.

This ink jet head has a nozzle 45
Are arranged in a line, and the bottom surface of the concave portion 54 of the electrode substrate 42 is formed in parallel with the diaphragm 42, and the electrode 55 is formed on the bottom surface of the concave portion 54. The gap 56 is arranged as a parallel gap. The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, ink jet heads according to the third to fifteenth embodiments of the present invention including the microactuator according to the present invention will be described with reference to FIGS. Each drawing is a cross-sectional explanatory view of a main part showing a portion of a flow path substrate and a diaphragm. The configuration of the first embodiment or the second embodiment can be applied to all other portions.

The third embodiment shown in FIG.
Is formed of a silicon nitride film 81 which is an insulating film having a tensile stress, and the diaphragm 42 has a tensile stress as a whole. Since the silicon nitride film 81 itself is an insulating film and cannot function as an electrode, an additional electrode film is formed when electrostatic force is used (the same applies to the following embodiments).

The silicon nitride film 81 is formed, for example, by CVD.
(Chemical-Vaper-Deposition) method. As the CVD method, a low pressure CVD method and a plasma CVD method are known, but a film formed by the low pressure CVD method has a larger tensile stress than a film formed by the plasma CVD method.

The absolute value of the tensile stress differs depending on the film forming conditions even if the same film forming method is used. In this case, if the tensile stress is too large, the flow path substrate 41 may be warped, the rigidity of the diaphragm may be significantly affected, or the membrane may be damaged when the membrane enters a membrane (diaphragm) state. Set an appropriate stress value.

The fourth embodiment shown in FIG.
1, a buffer oxide film 82 for etching stop is formed, and the vibration plate 42 is formed of a silicon nitride film 81 which is an insulating film having tensile stress and a silicon oxide film (layer) 83 which is an insulating film having compressive stress. The vibration plate 42 has tensile stress as a whole. That is, the tensile stress of the silicon nitride film 81 is relaxed by the compressive stress of the silicon oxide film 83, and the film as a whole has a tensile stress.

As described above, by combining the insulating film film having the tensile stress property and the insulating film having the compressive stress property, the tensile stress can be reduced by the compressive stress. Stress can be easily obtained.

The fifth embodiment shown in FIG.
Is formed of a four-layered film of a buffer oxide film 84 (the buffer oxide film 82 of the fourth embodiment is left as it is), a silicon nitride film 81, a silicon oxide film 83, and a silicon nitride film 81. The diaphragm 42 is formed as a film having tensile stress properties as a whole. Also in this case, the oxide film 8
The combination of the silicon nitride films 81 and 81 and the silicon nitride films 81 and 81 makes it possible to easily obtain an appropriate tensile stress on the diaphragm 42 as a whole.

The sixth embodiment shown in FIG.
Formed of a conductive film 85 made of a TiN film, a polysilicon film, or a high-temperature metal film such as Ti, W, or Mo having tensile stress, and the diaphragm 42 has tensile stress as a whole. . If direct bonding with the silicon substrate cannot be performed when the conductive film 85 is used, anodic bonding or eutectic bonding may be used as described above. Further, by using the conductive film 85, the diaphragm 42 can be used as a common electrode as it is.

The seventh embodiment shown in FIG.
Is formed of a laminated film of a silicon nitride film 81 which is an insulating film having tensile stress and a conductive film 85 having tensile stress, and the diaphragm 42 also has tensile stress as a whole. In this case, the insulating silicon nitride film 81 is used, but the conductive film 85 can be used as an electrode film.

The eighth embodiment shown in FIG.
Is formed by a laminated film of a silicon nitride film 81 which is an insulating film having tensile stress, a conductive film 85 having tensile stress and a silicon oxide film 83 which is an insulating film having compressive stress. 42 as a whole has tensile stress properties.

Also in this case, the tensile stress of the silicon nitride film 81 and the conductive film 85 is relaxed by the compressive stress of the silicon oxide film 83, so that the required tensile stress of the entire diaphragm 42 can be easily obtained. Further, a conductive film 85 is provided between the silicon nitride film 81 and the silicon oxide film 83 which are insulating films.
Are sandwiched, so that the conductive film 85 can be used as an electrode film (which becomes a common electrode), and the contact between the conductive film 85 and the counter electrode is made by the silicon oxide film 8.
3 can prevent it.

The ninth embodiment shown in FIG.
1, a buffer oxide film 82 for etching stop is formed, and the vibration plate 42 is formed by forming a silicon nitride film 81 which is an insulating film having tensile stress, a conductive film 85 and a silicon oxide film having compressive stress similarly to the eighth embodiment. It is formed by a laminated film with the film 83.

The tenth embodiment shown in FIG.
2 is a silicon oxide film 84 which is a compressive stress insulating film.
(The buffer oxide film 82 of the ninth embodiment is left as it is.), A laminated film of a conductive film 85 having tensile stress and a silicon nitride film 81 which is an insulating film having tensile stress. The diaphragm 42 has tensile stress as a whole.

Also in this case, the tensile stress of the silicon nitride film 81 and the conductive film 85 can be relaxed by the compressive stress of the silicon oxide film 84, and the required tensile stress of the entire diaphragm 42 can be easily obtained. Further, a conductive film 85 is provided between the silicon oxide film 84 and the silicon nitride film 81 which are insulating films.
Is sandwiched, so that the conductive film 85 can be used as an electrode film (which becomes a common electrode), and the contact between the conductive film 85 and the counter electrode is made by the silicon nitride film 8.
1 can prevent it.

The eleventh embodiment shown in FIG.
2 is a silicon nitride film 81 which is a tensile stress insulating film.
Formed to have tensile stress properties as a whole,
In order to use 2 as an electrode, a conductive layer 86 as an electrode film is formed on the silicon nitride film 81, and the conductive layer 86 is separated for each bit (each channel). As the conductive layer 86, a TiN film, a polysilicon film, a high-temperature metal film such as Ti, W, and Mo as described above, and other materials similar to those of the above-described electrode 55 can be used. In this case, the conductive layer 86 is not limited to a tensile stress conductive film.

By providing the conductive layer 86 divided for each bit on the vibration plate 42 side, it is not necessary to provide an individual electrode on the electrode substrate side. Note that the conductive film 8 which also serves as an electrode film inside as in the ninth and tenth embodiments described above.
Similarly, when 5 is stacked, the bit can be separated for each bit.

The twelfth embodiment shown in FIG.
2 is a silicon nitride film 81 which is a tensile stress insulating film.
Formed to have tensile stress properties as a whole,
In order to use 2 as an electrode, a conductive layer 86 which is an electrode film separated for each bit is formed on the silicon nitride film 81, and an insulating film 87 covering the conductive layer 86 is further formed. The conductive layer 86 is not limited to a film having a tensile stress, and the insulating film 87 is not limited to a film having a compressive stress.

By providing the conductive layer 86 divided for each bit on the vibration plate 42 side in this way, it is not necessary to provide an individual electrode on the electrode substrate side, and this conductive layer 86
Is formed, an electrical contact (short circuit, destruction) with the counter electrode can be prevented.

Further, it has been confirmed that when the protective film (insulating film) 57 is formed only on the counter electrode 55, the generation of residual charges is significantly increased. The residual charge is the vibration plate 42
Is a phenomenon in which when an electrode comes into contact with the counter electrode 55, electric charges remain on the surface, interface, or inside of a protective film (insulating film) sandwiched therebetween (there is a thought that the insulating film is polarized). Although there are still many unknown mechanisms of the residual charge, when the protective film (insulating film) is formed on both the diaphragm 42 and the counter electrode 55, the residual charge is practically used to the extent that it does not hinder the driving of the actuator. Has been confirmed to be suppressed. That is, by forming the insulating film 87 on the diaphragm 42 as in this embodiment, the generation of residual charges can be practically suppressed.

In the thirteenth embodiment shown in FIG. 22, a buffer oxide film 82 is formed on a flow path substrate 41, and a vibration plate 42 is formed of a silicon nitride film 81 which is an insulating film having a tensile stress. The diaphragm 42 has a tensile stress property.
Conductive layers 88 and 8 which are electrode films which are separated for each bit (channel) so that
8 and an insulating film 89 such as a silicon oxide film thicker than the conductive layer 88 is formed on the diaphragm 42 between the divided conductive layers 88 and 88. Also, the diaphragm 4
An insulating film 79 is also provided on a portion corresponding to the second pressure chamber spacing wall.

By providing the conductive layer 88 divided for each bit on the vibration plate 42 side in this way, it is not necessary to provide an individual electrode on the electrode substrate side, and this conductive layer 88
By forming the insulating film 89 having a larger thickness, electrical contact with the counter electrode can be prevented, and generation of residual charge can be reduced.

In the fourteenth embodiment shown in FIG. 23, a buffer oxide film 82 is formed on a flow path substrate 41, and a vibration plate 42 is formed of a silicon nitride film 81 which is an insulating film having tensile stress. The diaphragm 42 has a tensile stress property.
Conductive layers 88 and 8 which are electrode films which are separated for each bit (channel) so that
8 and an insulating film 89 such as a silicon oxide film thicker than the conductive layer 88 is formed on the diaphragm 42 between the divided conductive layers 88 and 88. In addition, a portion corresponding to the pressure chamber spacing wall of the vibration plate 42 serves as a gap spacer for defining the length of the gap 56 between the vibration plate 42 and the electrode 55 and an insulating portion serving as a joint portion with the electrode substrate 43. A film 90 is provided.

Therefore, in addition to the function and effect of the thirteenth embodiment, it is not necessary to provide the concave portion 54 for defining the gap length on the electrode substrate 43 side, and the flat silicon substrate can be used as it is as the electrode substrate. it can.

The fifteenth embodiment shown in FIG.
In addition to the fourth embodiment, an insulating film 91 also serving as a protective film for the conductive layers 88 and 88 is formed. By doing so, the residual charges can be more reliably reduced.

Next, ink jet heads including a microactuator according to the sixteenth to twentieth embodiments of the present invention will be described with reference to FIGS. 25 to 29. In addition, each drawing is a cross-sectional explanatory view in the transverse direction of the diaphragm.

The sixteenth embodiment shown in FIG.
2 is used, and a silicon oxide layer 43 is formed on an electrode substrate 43 made of a silicon substrate.
a, and a gap 56 is formed in the silicon oxide layer 43a.
A concave portion 54 to be formed is formed leaving a portion to be an electrode protective film (protective layer) 57, and the vibration plate 4 is formed on the electrode substrate 43.
2 etc. are joined.

Therefore, by applying a drive waveform using the conductive layer 86 of the diaphragm 42 as an individual electrode and the entire electrode substrate 43 as a common electrode, the diaphragm 42 is deformed and displaced, and ink droplets are ejected from the nozzle 45. . Thus, the diaphragm 42
Is divided for each individual bit,
The electrode substrate 43 can be used as a common electrode.

The seventeenth embodiment shown in FIG.
The second embodiment uses the one of the twelfth embodiment (FIG. 21), and the gap spacer 9
The vibration plate 42 and the like are joined through the intermediary 2 and a gap 56 having a predetermined length is formed between the vibration plate 42 and the plate-like electrode substrate 43 serving as a counter electrode. Also in this embodiment, the entire electrode substrate 43 is used as a common electrode.

The eighteenth embodiment shown in FIG.
The eleventh embodiment (FIG. 20) is used as the second electrode 2. A silicon oxide layer 43 is formed on an electrode substrate 43 made of a silicon substrate.
a, and a gap 56 is formed in the silicon oxide layer 43a.
Is formed except for a portion to be the electrode protection layer 57, and the vibration plate 42 and the like are joined on the electrode substrate 43. Also in this embodiment, the entire electrode substrate 42 is used as a common electrode.

The nineteenth embodiment shown in FIG.
The electrode substrate 43 of the twelfth embodiment (see FIG. 21) is used as the electrode substrate 2, and the electrode substrate of the second embodiment (see FIG. 11) is used as the electrode substrate.
A silicon oxide layer 43a is formed on the silicon oxide layer 43a, and a recess 54 serving as an electrode formation groove is formed in the silicon oxide layer 43a.
An electrode 55 is formed therein.

In this embodiment, the conductive layer 86 of the diaphragm 42 and the electrode 55 of the electrode substrate 43 correspond to each bit, and a drive waveform can be selected by selecting each bit.

The twentieth embodiment shown in FIG.
As the second embodiment, the one of the fourteenth embodiment (FIG. 23) is used.
The insulating layer 90 which becomes the gap spacer member on the side is joined.

In this case, the entire electrode substrate 43 is used as a common electrode. However, when the diaphragm 42 is deformed, the convex insulating layer 89 comes into contact with the electrode substrate 43 (works as a stopper). Contact (electric short-circuit) with the electrode substrate 43 can be prevented. Further, as described in the description of the twelfth embodiment, it is considered that the generation of the residual charges is caused by the protective film (insulating film). In the configuration of the present embodiment, since there is no insulating film on both electrode surfaces, there should be no generation of residual charges in principle. However, in practice, a natural oxide film is slightly formed on the silicon substrate surface. In addition, some residual charges are generated due to the influence of the discharge. Still,
By adopting the configuration as in the present embodiment, it is possible to suppress the residual charge to a level at which there is no practical problem.

Next, a process of manufacturing an ink jet head using the diaphragm according to the ninth embodiment will be described with reference to FIGS. First, a buffer oxide film 82 is formed on a silicon substrate 41 as shown in FIG. 1A (formed on both surfaces of the substrate) as shown in FIG.
Then, a silicon nitride film 81 is formed on the buffer oxide film 82 by a low pressure CVD method, a polysilicon film 85 as a conductive layer is formed on the silicon nitride film 81, and the surface of the polysilicon film 85 is The surface protection layer (silicon oxide film) 83 was formed by oxidation. In this case, since the polysilicon film has substantially the same thermal expansion coefficient as the silicon substrate 41, no stress is generated.

Next, the surface of the vibration plate (laminated film) 42, that is, the surface of the oxide film 83 is polished (polished), and the polished surface is formed with the electrode 55 and the like separately manufactured as shown in FIG. The surface of the electrode substrate 43 thus formed was joined by a silicon direct joining method as shown in FIG. In addition,
Naturally, the surface of the oxide layer 43a of the silicon substrate 43 is finished to have a surface property capable of directly bonding silicon without damage such as etching.

Next, as shown in FIG. 31A, after the silicon substrate 41 is polished to the discharge height, a mask pattern 95 corresponding to the pressure chamber 46 and the like is formed by, for example, plasma CVD.
It is formed by removing the nitride film formed by the method according to the pattern. Then, as shown in FIG. 4B, the silicon substrate 4 is subjected to alkaline etching using a KOH solution.
1 is etched to stop the etching by using the buffer oxide film 82 as an etch stop detection layer, and remove the remaining buffer oxide film 82 to form a concave portion to be the pressure chamber 46 and a diaphragm for forming the wall surface (bottom surface) thereof. 42 is formed. After that, as shown in FIG.
The nozzle plate 44 manufactured as shown in FIG.
Joining on the top to complete the inkjet head.

Next, an ink jet head according to a twentieth embodiment of the present invention will be described with reference to FIGS. FIG. 32 is an explanatory plan view of the head, and FIG.
3 is an explanatory cross-sectional view in the longitudinal direction of the diaphragm along the line CC in FIG. 32, and FIG. 34 is an explanatory cross-sectional view in the lateral direction of the diaphragm along the line DD in FIG.

This ink jet head is provided with a diaphragm 42
Is a piezo-type head provided with a piezoelectric element 96 for deforming and displacing. Note that an electrode 97 connected to the piezoelectric element 96 is provided on the electrode substrate 42. The present invention can be applied to such a piezo type head and a microactuator.

Next, the tensile stress of the diaphragm 42 will be described. In order to evaluate the film stress of the diaphragm and the bending state of the diaphragm, a TiN film was formed on a silicon substrate by an RF sputtering apparatus, and the film was used as a diaphragm or as a part of the diaphragm. The gas pressure dependency and the gas flow rate ratio dependency of the bending and deformation were evaluated. Table 1 shows the evaluation results of the gas pressure dependency, and Table 2 shows the evaluation results of the gas flow ratio dependency.
Is shown in The standard conditions are reactive gas Ar / N
2. The gas pressure is 6E-03Torr.

[0100]

[Table 1]

[0101]

[Table 2]

From these evaluation results, it was found that the film of the tensile stress type was good without any bending as a diaphragm, but the film of the compressive stress type was bent. However, TiN /
In the case of using a structure made of Si (110), if the stress is too large (about 1E + 11 dyne / cm ² ), a phenomenon that a crack is formed on the Si (111) plane perpendicular to the Si (110) at the time of passing through a thermal history or the like (defective) ) Occurred. This is Si (111)
This is because the surface is originally a surface that is easily broken.

In the case of an actuator using a small gap (about 1 μm or less) as in the present invention, the flexure or dent of the diaphragm is fatal, and in order to prevent this, the diaphragm must have tensile stress as a whole. However, from the viewpoint of high yield in the production process and reliability and durability (for example, from the viewpoint of preventing cracks), it is better that the tensile stress is not too large, and the material used for the diaphragm and its forming method Or, in the case of a laminated film, its configuration (film thickness, material, lamination order, etc.)
Although it is presumed that they are different from each other, it is preferable that the value does not exceed 1E + 11 (dyne / cm ² ) from the above-described evaluation results.

Next, the ink contact property of the vibration plate 42 will be described. Table 3 shows the results of evaluating the ink wettability of various materials. In the same table, ○ indicates that the film veri in 5 years does not affect device driving.
The symbol “Δ” indicates that the film veri in 5 years is estimated to affect the device driving, and the symbol “x” indicates that the film veri in 5 years affects the device driving.

[0105]

[Table 3]

Here, the ink resistance is evaluated by pH. According to the evaluation results, the Si or B diffusion layer has a large amount of film erosion due to the ink, which affects device driving. The thermal oxide film and the SiN film have little effect if the ink has a pH of about 7. Further, a TiN film, a Zr film, and the like exhibit good ink resistance in a wide range (at least up to about pH 11). On the other hand, Ni is an advantageous material when an ink having a high pH is used.

Therefore, the diaphragm to which the present invention is applied is
It is important that the entire diaphragm has a tensile stress within the allowable range. When forming a diaphragm with a laminated film, provide a material with high ink resistance on the liquid flow path side. Is preferred.

In each of the above embodiments, the present invention has been described as an example in which the present invention is applied to an ink jet head. However, the present invention can be applied to a droplet discharge head which discharges a liquid resist or the like. In addition, although the present invention is applied to a head having a resolution of 300 dpi or more, the present invention can be applied to a head having a resolution of less than 300 dpi, and the same operation and effect can be obtained. Further, although the description has been given of the example in which the microactuator according to the present invention is applied to the actuator section of the ink jet head, it can be applied to an actuator section such as a micropump. Furthermore, a silicon nitride film as an insulating film having a tensile stress property, a silicon oxide film or boron glass as an insulating film having a compressive stress property, and a titanium nitride film, a polysilicon film, and a high-temperature metal film as a conductive film. However, it is not limited to these.

[0109]

As described above, according to the droplet discharge head according to the present invention, since the diaphragm is made of an insulating film having a tensile stress property, an ultra-thin layer with high planar accuracy and small thickness variation is provided. Therefore, it is possible to obtain a high-density head which can be driven at a low voltage and has no variation in the droplet discharge characteristics.

Here, by using a silicon nitride film as the insulating film, a diaphragm having tensile stress can be easily formed. Further, by having an electrode film on the surface of the diaphragm, the diaphragm can be used as an electrode.

According to the droplet discharge head of the present invention, since the vibration plate is formed of a laminated film of insulating films and has a tensile stress property as a whole, it is extremely thin with high planar accuracy and small thickness variation. Since the diaphragm of the layer can be formed, it is possible to obtain a high-density head that can be driven at a low voltage and has no variation in the droplet discharge characteristics, and it is possible to easily obtain an appropriate tensile stress property of the entire diaphragm. it can.

Here, since the silicon nitride film is included in the film forming the laminated film, an insulating film having a tensile stress can be easily obtained. By including the oxide film, the tensile stress of the entire laminated film can be easily adjusted. Further, by having an electrode film on the surface or inside the laminated film, the diaphragm can be used as an electrode.

When the electrode film is provided, the electrode film is separated for each bit, so that the counter electrode side when the diaphragm is deformed and displaced by electrostatic force can be used as a common electrode. The configuration is simplified.

According to the droplet discharge head according to the present invention, since the diaphragm is made of a conductive film having tensile stress, it is possible to form a diaphragm having an extremely thin layer with a small thickness variation with high planar accuracy. It is possible to obtain a high-density head which can be driven at a low voltage and has no variation in droplet discharge characteristics.
Here, when the conductive film is a titanium nitride film, a high-temperature metal film, or a polysilicon film, a film having tensile stress can be easily obtained.

According to the droplet discharge head of the present invention, since the diaphragm is formed of a laminated film of conductive films and has a tensile stress property as a whole, it is extremely thin with high planar accuracy and small thickness variation. Since the diaphragm of the layer can be formed, it is possible to obtain a high-density head that can be driven at a low voltage and has no variation in droplet discharge characteristics. Here, a film having a tensile stress property can be easily obtained by using a titanium nitride film, a high-temperature metal film, or a polysilicon film as the film forming the laminated film.

According to the droplet discharge head of the present invention, since the diaphragm is formed of a laminated film of an insulating film and a conductive film and has a structure having tensile stress as a whole, the thickness is improved with high planar accuracy. Since a diaphragm with an extremely thin layer with small variations can be formed, a high-density head that can be driven at a low voltage and has no variation in droplet discharge characteristics can be obtained.
The diaphragm can also serve as the electrode.

Here, since the film forming the laminated film includes a silicon nitride film, it can easily have a tensile stress property. Since the silicon oxide film is included, the tensile stress can be reduced by a compressive stress. Moderate tensile stress can be easily obtained by relaxation. Furthermore, since the film forming the laminated film includes a titanium nitride film, a high-temperature metal film, or a polysilicon film, the film can easily have tensile stress.

According to the droplet discharge head of the present invention, the diaphragm is a laminated film of a film having a tensile stress and a film having a compressive stress, and has a structure having a tensile stress as a whole. A moderate tensile stress can be obtained,
Since an extremely thin diaphragm having a small thickness variation can be formed with high planar accuracy, a high-density head that can be driven at a low voltage and has no variation in droplet ejection characteristics can be obtained.

Here, the tensile stress film is an insulating film, a laminated film of an insulating film, a conductive film, a laminated film of a conductive film, or a laminated film of an insulating film and a conductive film. High tensile stress properties. In this case, since the compressive stress film is an insulating film, contact with the electrode can be prevented when the diaphragm is deformed and displaced by electrostatic force while relaxing the tensile stress.

Further, by forming the diaphragm as a laminated film of a silicon nitride film and a silicon oxide film, an appropriate tensile stress can be easily provided. Further, the diaphragm is made of a titanium nitride film, a high-temperature metal film, a polysilicon film,
With the laminated film of the film of the combination described above and the silicon oxide film, the diaphragm can also serve as the electrode.

Each of the droplet discharge heads according to the present invention can perform high-speed, high-density recording by setting the discharge density to 300 dpi or more. Also, the tensile stress of the diaphragm is 1E
By not exceeding +11 (dyne / cm ² ), breakage of the diaphragm due to tensile stress can be prevented. Further, the flow path side surface of the diaphragm has a higher liquid contact property than a layer in which high-concentration boron is diffused in silicon, so that reliability can be secured for a long period of time. Further, it is preferable that the thickness of the diaphragm is within a range having a rigidity equivalent to that of a silicon diaphragm having a thickness of 0.3 μm to 1.5 μm, so that even if the diaphragm is arranged at a high density, sufficient vibration can be obtained at a low voltage. Plate displacement can be ensured.

Each of the droplet discharge heads according to the present invention has an electrode facing the diaphragm and discharges droplets by displacing the diaphragm with electrostatic force, thereby achieving high speed and high speed. An electrostatic head capable of density recording can be obtained. Or,
A piezo-type head capable of high-speed and high-density recording can be obtained by having a configuration in which an electromechanical transducer is used to deform the diaphragm, and droplets are ejected by displacing the diaphragm by displacement of the electromechanical transducer. .

According to the ink jet recording apparatus of the present invention, an ink jet head having a nozzle for discharging ink droplets, an ink flow path communicating with the nozzle, and pressure generating means for pressurizing ink in the ink flow path. Is a droplet discharge head according to the present invention, so that high-speed, high-density recording can be performed.

According to the microactuator of the present invention, since the vibration plate and the driving means for deforming the vibration plate are provided and the vibration plate has a tensile stress property as a whole, the thickness can be increased with high plane accuracy. It is possible to form an ultra-thin layer diaphragm with small variations, and obtain an actuator that can be driven at a low voltage and arranged at a high density.

The diaphragm is made of an insulating film, a laminated film of an insulating film, a conductive film, a laminated film of a conductive film, or a laminated film of an insulating film and a conductive film, so that a suitable tensile strength can be obtained. Stress can be easily provided.

According to the microactuator of the present invention, the diaphragm is provided with a driving means for deforming the diaphragm, and the diaphragm is a laminated film of a tensile stress film and a compressive stress film. Because it has a structure with tensile stress as a whole, it can have an appropriate tensile stress, it can form a diaphragm of ultra-thin layer with high plane accuracy and small thickness variation, low voltage driving and high density arrangement A possible actuator is obtained.

In the microactuator according to the present invention, the diaphragm has a tensile stress of 1E + 11 (dyne / cm
^By not exceeding ² ), it is possible to prevent the diaphragm from being damaged by tensile stress. The thickness of the diaphragm is 0.3
By setting the rigidity within the range having the same rigidity as that of the silicon diaphragm having a thickness of μm to 1.5 μm, it is possible to secure a sufficient diaphragm displacement at a low voltage. Furthermore, by providing an electrode facing the diaphragm and displacing the diaphragm with electrostatic force, an electrostatic actuator that can be driven at a low voltage and has a high density arrangement can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic perspective explanatory view of a mechanism section of an ink jet recording apparatus according to the present invention.

FIG. 2 is an explanatory side sectional view of the recording apparatus.

FIG. 3 is an exploded perspective view of the inkjet head according to the first embodiment of the invention.

FIG. 4 is an explanatory cross-sectional view of the head in the longitudinal direction of the diaphragm.

FIG. 5 is an enlarged view of a main part of FIG. 4;

FIG. 6 is an explanatory cross-sectional view of the head in a lateral direction of the diaphragm.

FIG. 7 is an explanatory plan view of a main part showing the head in a transparent state;

FIG. 8 is an explanatory diagram illustrating a steady state of a diaphragm in a head using a conventional diaphragm.

FIG. 9 is an explanatory plan view of an inkjet head according to a second embodiment of the present invention.

FIG. 10 is an explanatory cross-sectional view in the longitudinal direction of the diaphragm along the line AA in FIG. 9;

FIG. 11 is an explanatory cross-sectional view taken along the line BB of FIG. 9 in the transverse direction of the diaphragm.

FIG. 12 is an explanatory cross-sectional view of a main part of an ink jet head according to a third embodiment of the invention in a lateral direction of a diaphragm.

FIG. 13 is an explanatory cross-sectional view of a main part of an ink jet head according to a fourth embodiment of the invention in a lateral direction of a diaphragm.

FIG. 14 is an explanatory cross-sectional view of a main part in a lateral direction of a diaphragm of an inkjet head according to a fifth embodiment of the present invention.

FIG. 15 is an explanatory cross-sectional view of a main part of an ink jet head according to a sixth embodiment of the invention, taken along a lateral direction of a diaphragm.

FIG. 16 is an explanatory cross-sectional view of a main part of an ink jet head according to a seventh embodiment of the invention in a lateral direction of a diaphragm.

FIG. 17 is an explanatory cross-sectional view of a main part of an ink jet head according to an eighth embodiment of the invention in a lateral direction of a diaphragm.

FIG. 18 is an explanatory cross-sectional view of a main part of an ink jet head according to a ninth embodiment of the present invention in a lateral direction of a diaphragm.

FIG. 19 is an explanatory cross-sectional view of a principal part in a lateral direction of a diaphragm of an inkjet head according to a tenth embodiment of the present invention.

FIG. 20 is an explanatory cross-sectional view of a main part of an inkjet head according to an eleventh embodiment of the present invention in a lateral direction of a diaphragm.

FIG. 21 is an explanatory cross-sectional view of a main part of an inkjet head according to a twelfth embodiment of the present invention, taken along the width direction of the diaphragm.

FIG. 22 is an explanatory cross-sectional view of a principal part in a lateral direction of a diaphragm of an inkjet head according to a thirteenth embodiment of the present invention.

FIG. 23 is an explanatory cross-sectional view of a main part of an inkjet head according to a fourteenth embodiment of the present invention, taken along a lateral direction of a diaphragm.

FIG. 24 is an explanatory cross-sectional view of a main part of an ink jet head according to a fifteenth embodiment of the present invention, taken along a lateral direction of a diaphragm.

FIG. 25 is an explanatory cross-sectional view of an ink jet head according to a sixteenth embodiment of the present invention, taken along a lateral direction of a diaphragm.

FIG. 26 is an explanatory cross-sectional view of an ink jet head according to a seventeenth embodiment of the present invention, taken along a lateral direction of a diaphragm.

FIG. 27 is an explanatory cross-sectional view of an ink-jet head according to an eighteenth embodiment of the present invention, taken along a lateral direction of a diaphragm.

FIG. 28 is an explanatory cross-sectional view of an ink-jet head according to a nineteenth embodiment of the present invention, taken in a lateral direction of a diaphragm.

FIG. 29 is an explanatory cross-sectional view of an ink jet head according to a twentieth embodiment in a lateral direction of a diaphragm.

FIG. 30 is an explanatory diagram for explaining a manufacturing process of the inkjet head according to the ninth embodiment.

FIG. 31 is an explanatory view illustrating a manufacturing process of the head.

FIG. 32 is an explanatory plan view of an inkjet head according to a twenty-first embodiment of the present invention.

FIG. 33 is an explanatory cross-sectional view in the longitudinal direction of the diaphragm along the line CC in FIG. 32;

FIG. 34 is an explanatory cross-sectional view taken along the line DD of FIG. 32 in the transverse direction of the diaphragm.

[Explanation of symbols]

13: carriage, 14: head, 24: transport roller,
33: paper ejection roller, 40: ink jet head, 41
... flow path substrate, 42 ... diaphragm, 43 ... electrode substrate, 44 ... nozzle plate, 45 ... nozzle, 46 ... pressurizing chamber, 47 ... fluid resistance part, 48 ... common liquid chamber, 54 ... concave part, 55 ... electrode, 56 ...
Gap, 81: silicon nitride film, 83: silicon oxide film, 85: conductive film, 86, 88: conductive layer, 87: insulating film, 96: piezoelectric element.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2C057 AF37 AF55 AF93 AG14 AG16 AG30 AG53 AG54 AG55 AG99 AN01 AP02 AP14 AP25 AP27 AP28 AP33 AP38 AP53 AP56 AQ01 AQ02 AQ06 BA03 BA14 BA15

Claims (34)

[Claims] A diaphragm that forms a wall of the liquid flow path;
In a droplet discharge head that discharges droplets by deforming the vibration plate, the vibration plate is formed of an insulating film having tensile stress. 2. The droplet discharge head according to claim 1, wherein said insulating film is a silicon nitride film. 3. The droplet discharge head according to claim 1, wherein the diaphragm has an electrode film on a surface of the vibration plate. 4. A vibration plate forming a wall surface of the liquid flow path,
In a droplet discharge head that discharges droplets by deforming the vibration plate, the vibration plate is formed of a laminated film of insulating films, and has a tensile stress as a whole. 5. The droplet discharge head according to claim 4, wherein the film forming the laminated film includes a silicon nitride film. 6. The droplet discharge head according to claim 4, wherein the film forming the laminated film includes a silicon oxide film. 7. The droplet discharge head according to claim 4, further comprising an electrode film on a surface or inside the laminated film. 8. The droplet discharge head according to claim 3, wherein the electrode film is separated for each bit. 9. A vibration plate forming a wall surface of a liquid flow path,
In a droplet discharge head that discharges droplets by deforming the vibration plate, the vibration plate is made of a conductive film having tensile stress. 10. The droplet discharge head according to claim 9, wherein the conductive film is a titanium nitride film, a high-temperature metal film, or a polysilicon film. 11. A droplet discharge head that has a vibration plate that forms a wall surface of a liquid flow path and discharges droplets by deforming the vibration plate, wherein the vibration plate is formed of a laminated film of a conductive film. And a droplet discharge head having tensile stress as a whole. 12. The droplet discharge head according to claim 11, wherein the film forming the laminated film includes a titanium nitride film, a high-temperature metal film, or a polysilicon film. 13. A droplet discharge head that has a diaphragm that forms a wall surface of a liquid flow path and discharges droplets by deforming the diaphragm, wherein the diaphragm includes an insulating film and a conductive film. Characterized by having a tensile stress as a whole. 14. The droplet discharge head according to claim 13, wherein the film forming the laminated film includes a silicon nitride film. 15. The droplet discharge head according to claim 13, wherein the film forming the laminated film includes a silicon oxide film. 16. The droplet discharge head according to claim 13, wherein the film forming the laminated film includes a titanium nitride film, a high-temperature metal film, or a polysilicon film. Droplet ejection head. 17. A droplet discharge head that has a vibration plate that forms a wall surface of a liquid flow path and discharges a droplet by deforming the vibration plate, wherein the vibration plate is formed of a film having a tensile stress and a compression film. A droplet discharge head which is a laminated film with a film having a stress property and has a tensile stress property as a whole. 18. The droplet discharge head according to claim 17, wherein the tensile stress film is an insulating film, a laminated film of an insulating film, a conductive film, a laminated film of a conductive film or an insulating film. A droplet discharge head, which is a laminated film with a conductive film. 19. The droplet discharge head according to claim 17, wherein the compressive stress film is an insulating film. 20. The droplet discharge head according to claim 17, wherein the vibration plate is a stacked film of a silicon nitride film and a silicon oxide film. 21. The droplet discharge head according to claim 17, wherein the vibration plate is a titanium nitride film, a high-temperature metal film, a polysilicon film, or a laminated film of a film of a combination of two or more of these and a silicon oxide film. A droplet discharge head, comprising: 22. The droplet discharge head according to claim 1, wherein the discharge density of the head is 30.
A droplet discharge head having a resolution of 0 dpi or more. 23. The droplet discharge head according to claim 1, wherein the diaphragm has a tensile stress of 1%.
E + 11 (dyne / cm ² ). 24. The droplet discharge head according to claim 1, wherein the surface of the diaphragm on the flow path side has a higher liquid contact property than a layer in which high-concentration boron is diffused into silicon. A droplet discharge head characterized in that: 25. The droplet discharge head according to claim 1, wherein the diaphragm has a thickness of 0.3 μm.
A droplet discharge head having a rigidity equivalent to that of a silicon diaphragm having a thickness of m to 1.5 μm. 26. The droplet discharge head according to claim 1, further comprising an electrode facing the vibration plate, and discharging the liquid droplet by displacing the vibration plate with electrostatic force. A droplet discharge head characterized in that: 27. The droplet discharge head according to claim 1, further comprising: an electromechanical transducer for deforming the diaphragm, wherein the diaphragm is displaced by displacement of the electromechanical transducer. A droplet discharge head characterized by discharging droplets by the above method. 28. An ink jet recording apparatus equipped with an ink jet head having a nozzle for discharging ink droplets, an ink flow path communicating with the nozzle, and pressure generating means for pressurizing ink in the ink flow path. An ink jet recording apparatus comprising the liquid droplet ejection head according to any one of claims 1 to 27. 29. A microactuator comprising a diaphragm and driving means for deforming the diaphragm, wherein the diaphragm has tensile stress as a whole. 30. The microactuator according to claim 29, wherein the vibration plate is an insulating film, a laminated film of an insulating film, a conductive film, a laminated film of a conductive film, or a film of an insulating film and a conductive film. A microactuator characterized by being a laminated film. 31. In a microactuator comprising a diaphragm and a driving means for deforming the diaphragm, the diaphragm is a laminated film of a film having a tensile stress and a film having a compressive stress. A microactuator having stress properties. 32. The microactuator according to claim 29, wherein a tensile stress of the diaphragm does not exceed 1E + 11 (dyne / cm ² ). 33. The microactuator according to claim 29, wherein the thickness of the diaphragm is within a range having a rigidity equivalent to that of a silicon diaphragm having a thickness of 0.3 μm to 1.5 μm. A microactuator characterized by the following. 34. The microactuator according to claim 29, further comprising an electrode facing the diaphragm, wherein the diaphragm is displaced by electrostatic force.