JP2009029062A - Droplet ejection head, manufacturing method of droplet ejection head, and droplet ejection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a droplet ejection head or the like which can provide stable ejection characteristics, causes no pressure interference between nozzles and is not affected by a change in outside atmospheric pressure, further, can be made compact and can easily materialize high density and the large number of the nozzles. <P>SOLUTION: The droplet ejection head includes: a nozzle board 1 formed with a plurality of nozzle holes 5 for ejecting a droplet; a cavity board 2 which has a bottom wall forming a vibrating plate 7 and which is formed with a recessed portion serving as an ejection chamber 6 for each nozzle hole; an electrode board 3 which faces the vibrating plate and is formed with a plurality of individual electrodes 8 driving the vibrating plate; and a reservoir board 4 which is formed with a recessed portion serving as a first reservoir 11 for supplying the droplet to the ejection chamber. The nozzle board, the cavity board, the electrode board and the reservoir board are stacked and arranged in this order. The cavity board is provided with an opening serving as a second reservoir 12, the electrode board is provided with an opening serving as a third reservoir 13 and the recessed portion serving as the first reservoir, the opening serving as the second reservoir and the opening serving as the third reservoir are communicated with each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a droplet discharge head used for an inkjet head or the like, a method for manufacturing the droplet discharge head, and a droplet discharge apparatus.

As a droplet discharge head for discharging droplets, for example, an inkjet head mounted on an inkjet recording apparatus is known. In general, an inkjet head includes a nozzle substrate in which a plurality of nozzle holes for discharging ink droplets are formed, and a discharge chamber, a reservoir unit, and the like that are joined to the nozzle substrate and communicate with the nozzle holes. And a cavity substrate having an ink flow path formed therein, and configured to discharge ink droplets from selected nozzle holes by displacing the vibration plate at the bottom of the discharge chamber by applying pressure to the discharge chamber by the drive unit. Has been. As the driving means, there are an electrostatic driving method using an electrostatic force, a piezoelectric driving method using a piezoelectric element, a method using a heating element, and the like.

Such ink-jet heads have been reduced in size from the past, and there is one disclosed in Patent Document 1, for example. This is based on a piezoelectric drive system, and has a structure in which an actuator, an ink pressure chamber (ejection chamber), and a common ink chamber (reservoir) are partitioned on different planes, and these are stacked.
Patent Document 2 discloses an ink jet head in which an actuator and an ink pressure chamber are partitioned and formed on different planes, and a common ink chamber is arranged vertically with respect to these.
Further, Patent Document 3 and Patent Document 4 disclose an edge ejection type or face ejection type inkjet head in which an actuator, an ink pressure chamber, and a common ink chamber are stacked and arranged.

However, if the ink jet head is further miniaturized, the common ink chamber is also miniaturized, and pressure interference between nozzles occurs due to a decrease in compliance. Therefore, for example, as shown in Patent Document 5, an ink jet head in which a reservoir substrate provided with a common ink chamber is disposed between a nozzle substrate and a cavity substrate has been proposed. However, in this structure, the reservoir substrate must be thick, and there is a limit to downsizing.

In addition, the actuator chamber formed between the diaphragm and the individual electrode is hermetically sealed and completely shut off from the outside air, so when the atmospheric pressure changes, the internal pressure of the actuator chamber changes, Along with this, the diaphragm having low rigidity is displaced, and the volume of the actuator chamber changes. As a result, the ink discharge amount is not stable, which causes the discharge characteristics to become unstable. Therefore, as a means for suppressing such displacement of the diaphragm, an ink jet head having the following structure is conventionally known.

For example, in Patent Document 6, a pressure compensation chamber having a displacement plate that can be displaced according to a change in external air pressure is formed in a cavity substrate. In this case, it is necessary to form a large pressure compensation chamber in the cavity substrate, and there is a problem that it is difficult to reduce the size of the inkjet head.
In Patent Document 7, a displacement plate that can be displaced according to a change in external air pressure is formed of a material other than a diaphragm or a member provided with an electrode, such as a polyimide film. In this case, a process of attaching the film with an adhesive or the like is necessary, and there is a problem that it is difficult to ensure the airtightness of the actuator chamber (also referred to as a vibration chamber).

JP-A-8-58089 JP 2001-334663 A JP 2001-253072 A JP 2006-272574 A JP 2006-103167 A WO99 / 47357 Publication JP 2003-94637 A

In recent years, there has been a demand for a recording apparatus that can increase the recording density and increase the recording speed for these conventional inkjet heads.
Therefore, it is necessary to further increase the density of arrangement of ink flow paths, actuators, and the like. For further downsizing of the head, the common ink chamber, wiring, IC mounting, etc., and the portion that occupies a large partition area in the inkjet head, such as a displacement plate that can be displaced according to changes in the external air pressure It is necessary to reduce the area of the ink in accordance with the increase in the density of the ink flow path and the actuator described above.

In view of the above-described problems, the present invention has no pressure interference between nozzles and is not affected by changes in external air pressure, and can obtain stable discharge characteristics and can be downsized. The purpose is to provide a droplet discharge head capable of easily realizing a higher density and a larger number of nozzles, and further, by mounting the droplet discharge head of the present invention, the apparatus can be miniaturized,
An object of the present invention is to provide a droplet discharge device that can cope with high-definition and high-quality droplet discharge and high-speed driving.

The droplet discharge head according to the present invention includes a nozzle substrate having a plurality of nozzle holes for discharging droplets, a cavity in which a bottom wall forms a vibration plate, and a recess to be a discharge chamber is formed for each nozzle hole. A substrate; an electrode substrate on which a plurality of individual electrodes that are opposed to the diaphragm and drive the diaphragm are formed; and a reservoir substrate on which a recess serving as a first reservoir for supplying droplets to the discharge chamber is formed. The nozzle substrate, cavity substrate, electrode substrate, and reservoir substrate are stacked in this order. The cavity substrate is provided with an opening serving as a second reservoir, and the electrode substrate has an opening serving as a third reservoir. The recessed portion that is provided and serves as the first reservoir, the opening that serves as the second reservoir, and the opening that serves as the third reservoir communicate with each other.

The droplet discharge head of the present invention includes three reservoirs. Therefore, since the volume of the reservoir is increased, the compliance is increased by the compression of the ejection liquid itself, and pressure interference between the nozzles is suppressed. Therefore, it is possible to realize a high-quality liquid droplet ejection head with stable ejection characteristics. In addition, since the nozzle substrate, cavity substrate, electrode substrate, and reservoir substrate are stacked in this order, three reservoirs can be stacked and the droplet discharge head can be reduced in size, increased in density, and multi-nozzle Can be realized.

In the liquid droplet ejection head of the present invention, it is preferable that a diaphragm is provided in the recess serving as the first reservoir. In order to suppress the pressure interference between the nozzles, it is possible only by expanding the volume of the reservoir. However, by providing a diaphragm in the recess serving as the first reservoir, the diaphragm absorbs (buffers) the pressure fluctuation in the reservoir. Therefore, it is more effective.

In the droplet discharge head of the present invention, it is preferable that the reservoir substrate is provided with a displacement plate that can be displaced according to a change in the external pressure.
Thus, the displacement plate can be provided using the same reservoir substrate, and the droplet discharge head can be miniaturized. Since the displacement plate that can be displaced according to the change in the external air pressure is provided, the displacement of the vibration plate due to the change in the external air pressure can be suppressed, and stable discharge without variation in the droplet discharge amount is possible.

In the droplet discharge head of the present invention, the reservoir substrate is silicon. Thereby, since the diaphragm is made of silicon, chemical resistance is improved. Further, the dimensional accuracy of the displacement plate can be ensured with high accuracy.

In the droplet discharge head of the present invention, the cavity substrate, the electrode substrate, and the reservoir substrate are preferably laminated by anodic bonding.
A high bonding strength can be ensured by anodic bonding, and the airtightness between the diaphragm and the individual electrodes can be increased.

In the droplet discharge head of the present invention, the driver IC connected to the individual electrode is preferably mounted on the same surface as the surface on which the individual electrode is formed on the electrode substrate.
As a result, the driver IC can be easily mounted, the wiring and the IC mounting area can be reduced, and the droplet discharge head itself can be reduced in size.

A droplet discharge apparatus according to the present invention is equipped with any of the above droplet discharge heads.
As a result, the apparatus can be miniaturized, and a liquid droplet ejection apparatus that can cope with high-definition, high-quality liquid droplet ejection and high-speed driving can be realized.

A method for manufacturing a droplet discharge head according to the present invention includes forming a plurality of nozzle holes in a silicon substrate,
A step of obtaining a nozzle substrate, a step of forming a cavity substrate on a silicon substrate, forming a plurality of recesses serving as discharge chambers, and an opening serving as a second reservoir to obtain a cavity substrate, and glass Forming an individual electrode for driving the diaphragm and an opening serving as a third reservoir on the substrate to obtain an electrode substrate; forming a recess serving as the first reservoir on the silicon substrate; A nozzle substrate, a cavity substrate, an electrode substrate, and a reservoir substrate are laminated in this order, and the cavity substrate and the electrode substrate, and the electrode substrate and the reservoir substrate are anodically bonded.

With this manufacturing method, multiple reservoirs can be produced, stable ejection characteristics without pressure interference between nozzles can be obtained, and miniaturization is possible, and high density and multiple nozzles can be easily realized. A droplet discharge head capable of achieving the above is obtained.

Hereinafter, an embodiment of a droplet discharge head to which the present invention is applied will be described with reference to the drawings. Here, an electrostatic drive type inkjet head will be described with reference to FIGS. 1 and 2 as an example of a droplet discharge head. The present invention is not limited to the structure and shape shown in the following figures.

FIG. 1 is an exploded perspective view showing an exploded schematic configuration of an inkjet head according to an embodiment of the present invention, and a part thereof is shown in a sectional view. FIG. 2 is a partial cross-sectional view of the ink jet head in an assembled state.
The inkjet head 10 is configured by stacking four substrates, a nozzle substrate 1, a cavity substrate 2, an electrode substrate 3, and a reservoir substrate 4, in this order. The ink jet head 10 has a configuration in which the nozzle holes 5 are formed in two rows per one, but the head portion may be configured to have a single row of nozzle holes 5. Further, the number of nozzle holes 5 is not limited.

The nozzle substrate 1 is made of, for example, a single crystal silicon substrate, and a plurality of nozzle holes 5 for discharging ink droplets are formed by drilling by dry etching.
The nozzle hole 5 has a small-diameter hole and a large-diameter hole formed in two stages concentrically, but the form and structure of the nozzle hole 5 are not limited to this. Further, a narrow groove 19 serving as an ink supply port 18 is formed on the joint surface of the nozzle substrate 1 with the cavity substrate 2. The narrow groove 19 may be provided on the upper surface of a partition wall that divides each discharge chamber 6 and the second reservoir 12 of the cavity substrate 2 described later.

The cavity substrate 2 is made of, for example, a single crystal silicon substrate having a plane orientation of (110), and is a recess 21 that becomes the discharge chamber 6 and a first ink chamber that is a common ink chamber for each discharge chamber 6 (recess 21). A through-opening 22 serving as the second reservoir 12 is formed. Here, the “through opening” means an opening provided in a state of penetrating the substrate, and is distinguished from a “concave portion” having a bottom surface.
The bottom wall of the recess 21 serving as the discharge chamber 6 is formed with high accuracy with a very thin thickness by, for example, a boron diffusion layer, and functions as the diaphragm 7 that performs out-of-plane deformation.
In addition, a driver IC, which will be described later, is provided at the substantially central portion of the cavity substrate 2 as shown in FIG.
50 IC insertion openings 23 are provided.
The nozzle substrate 1 in which the nozzle holes 5 described above are formed is bonded and bonded to the upper surface (the upper surface in FIG. 2) of the cavity substrate 2 thus configured.

The electrode substrate 3 is made of, for example, a borosilicate glass substrate, and a groove portion 31 is formed by etching in a portion corresponding to the vibration plate 7 on the upper surface (bonding surface with the cavity substrate 2) of the glass substrate. Further, individual electrodes 8 made of, for example, ITO (Indium Tin Oxide) are formed in the groove 31. Further, the glass substrate of the electrode substrate 3 is formed with a through opening 32 serving as the third reservoir 13 so as to be directly connected to the through opening 22 serving as the second reservoir 12. That is, as shown in FIG. 1, the through-opening 32 is located directly below the through-opening 22 and is formed in substantially the same shape as a large-area rectangular opening at the bottom thereof.
It is not always necessary to provide the third reservoir 13 on the electrode substrate 3. It is good also as a through-hole which connects the 1st reservoir | reserver 11 and the 2nd reservoir | reserver 12 which are provided in the reservoir | reserver board | substrate 4 mentioned later. However, the through hole is a narrow groove 19 that becomes the ink supply port 18 described above.
It is necessary that the cross-sectional area is sufficiently larger than that and the flow path resistance is low.

The individual electrode 8 is disposed opposite to the diaphragm 7 with a predetermined interval, and the space formed between the individual electrode 8 and the diaphragm 7 is hermetically sealed by a sealing material 35. Room 2
4 Although illustration is omitted, an insulating film for preventing dielectric breakdown, short circuit, or the like is formed on one or both of the diaphragm 7 and the individual electrode 8. Insulating film is SiO ₂
Or SiN, or a so-called High-k material (high dielectric constant insulating film) such as Al ₂ O ₃ or HfO ₂ is used. The diaphragm 7, the individual electrode 8, and the insulating film (not shown) constitute an electrostatic actuator.
A communication port 33 communicating with each actuator chamber 24 is provided through the glass substrate of the electrode substrate 3 and each individual electrode 8.

Furthermore, a driver IC 50 for driving the electrostatic actuator is mounted on the terminal portion 8a of each individual electrode 8. The driver IC 50 is an IC provided on the cavity substrate 2.
Through the insertion port 23, it is mounted on the same surface as the surface on which the electrostatic actuator (individual electrode 8) is formed. For this reason, the mounting of the driver IC 50 is facilitated.
An input wiring portion 51 and an FPC mounting terminal (IC input terminal) 52 to the driver IC 50 are formed at one or both side end portions of the glass substrate.

The driver IC 50 is bonded and mounted with an anisotropic conductive adhesive so as to be connected to the terminal portion of the individual electrode 8 formed on the glass substrate and the IC input terminal. FPC (not shown) is FP
It is connected to the C mounting terminal 52 and electrically connected to an external circuit.
The segment output terminals of the IC are connected to the terminal portions of these individual electrodes 8 by IC mounting.
The FPC mounting terminal 52 forms an IC input terminal and a common electrode terminal. The IC input terminal includes a power supply Vp for driving the electrostatic actuator, a power supply Vcc for driving the IC, and a ground potential GND.
And logic signal clock CLK, data DI, latch LP, and other terminals F
Wiring is formed between the PC mounting terminal and the IC mounting terminal. Further, the common electrode terminal is connected to a through-hole electrode (terminals on both outer sides of the FPC connection terminal row 52 not shown) connected to the cavity substrate 2 by wiring. In this embodiment, the common electrode terminal is connected to the FPC without passing through the driver IC 50.
In the electrode substrate 3 configured in this way, the cavity substrate 2 described above is anodically bonded to the upper surface of the glass substrate on which the individual electrodes 8 are formed.

The reservoir substrate 4 is made of, for example, a single crystal silicon substrate having a plane orientation of (100), and a recess 41 serving as the first reservoir 11 and a recess 42 serving as the pressure compensation chamber 16 are defined. . The recess 41 is formed of a deep first step recess 41a and a shallow second step recess 41b. The first step recess 41a and the second step recess 41b. Are connected via a rib-like stepped portion 41c. Further, the bottom of the first-stage recess 41a is formed thick, and the bottom of the second-stage recess 41b is formed thin by forming the recess 43 on the back side. With this configuration, the bottom of the second-stage recess 41 b forms the diaphragm 15. As described above, the diaphragm 15 is formed as a part of the bottom of the concave portion 41 to be the first reservoir 11 without enlarging the area.
In addition, since the diaphragm 15 is supported on one side by the rib-shaped step portion 41c, stable support and vibration operation of the diaphragm 15 can be ensured.
In addition, an ink intake port 44 is formed at the bottom of the first-stage recess 41a, and the connection member 4 is connected to the ink intake port 44 through an ink supply pipe (not shown).
5 is adhesively bonded.
Although the diaphragm 15 may be formed on the entire bottom surface of the recess 41, it is preferable that the bottom surface of the recess 41 is divided into a thick portion and a thin portion as described above. Recess 41
This is because the thick-walled portion is immobile and increases in strength, so that it is easy to attach the ink tank connecting means such as the ink intake port 44, and there is little risk of breakage or the like.

The bottom of the recess 42 that becomes the pressure compensation chamber 16 is formed from the both sides of the silicon substrate by the recess 42 and the recess 46.
Are formed as a displacement plate 17 having a rigidity lower than that of the diaphragm 7.
The thus configured reservoir substrate 4 is anodically bonded to the surface of the electrode substrate 3 opposite to the individual electrode 8.

Here, the operation of the inkjet head 10 will be briefly described. The ink is supplied from an ink tank (not shown), and from the first reservoir 11 provided on the reservoir substrate 4 to the third reservoir 13 or the through hole provided on the electrode substrate 3 and the first reservoir 11 provided on the cavity substrate 2. Each ink flow path is filled without generating bubbles until it reaches the tip of the nozzle hole 5 of the nozzle substrate 1 via the second reservoir 12, and the ink flows in the direction indicated by the arrow in FIG.
When performing printing, when a nozzle is selected by the driver IC 50 and a predetermined pulse voltage is applied between the diaphragm 7 and the individual electrode 8, electrostatic attraction is generated and the diaphragm 7 moves toward the individual electrode 8 side. It draws and bends, contacts the individual electrode 8 and generates a negative pressure in the discharge chamber 6. As a result, the ink in the second reservoir 12 is sucked into the discharge chamber 6 through the ink supply port 18 to generate ink vibration (meniscus vibration). When the voltage is released when the vibration of the ink becomes substantially maximum, the vibration plate 7 is detached from the individual electrode 8 and the ink is pushed out from the selected nozzle hole 5 by the restoring force of the vibration plate 7, and the ink droplet Are discharged toward a recording sheet (not shown).

  The inkjet head 10 according to this embodiment has the following effects.

Since the inkjet head 10 includes at least two, preferably three reservoirs, the volume of the common ink chamber can be increased. As a result, the compliance can be increased from the compression of the ink itself by expanding the volume of the common ink chamber. That is, the pressure absorption effect of absorbing the pressure fluctuation at the time of ink droplet ejection by the compression of the ink itself is improved. In addition, unless the second reservoir 12 has an extremely high aspect ratio, the common ink chamber serves as a flow path and the cross-sectional area is increased, so that the flow path resistance is also reduced. Therefore, by expanding the volume of the common ink chamber, it is possible to realize an inkjet head having stable ejection characteristics without pressure interference between the ink nozzles.
In addition, by providing the electrode substrate 3 with the third reservoir 13 as the third common ink chamber, the volume of the common ink chamber can be further increased, and the pressure absorption effect can be further improved. It becomes possible.

Further, since the first reservoir 11 is provided with the diaphragm 15, the pressure fluctuation in the common ink chamber can be absorbed by the vibration of the diaphragm 15, so that the ink jet head has stable ejection characteristics without pressure interference between the ink nozzles. Can be realized.
Further, since the diaphragm 15 is made of silicon, an ink jet head having more excellent chemical resistance can be configured.

The inkjet head 10 has a structure in which a nozzle substrate 1, a cavity substrate 2, an electrode substrate 3, and a reservoir substrate 4 are stacked in this order. Therefore, the inkjet head 10 is not enlarged in the longitudinal direction, and can be reduced by providing a plurality of reservoirs that occupy a large partition area, thereby reducing the size of the inkjet head, increasing the nozzle density, and increasing the number of nozzles. Can be realized simultaneously.

Since the driver IC 50 is mounted on the same surface as the surface on which the individual electrodes 8 of the electrode substrate 3 are formed, the driver IC 50 can be easily mounted, and the wiring and IC mounting area can be reduced. It has become. In addition, the electrode substrate 3 can be easily manufactured.

The reservoir substrate 4 is provided with a pressure compensation chamber 16 that communicates with the sealed actuator chamber 24 through a communication port 33, and the pressure compensation chamber 16 is provided with a displacement plate 17 that can be displaced in accordance with a change in external atmospheric pressure. Yes. Therefore, for example, when the external air pressure is lower than the internal pressure of the actuator chamber 24, the vibration plate 7 tends to be displaced upward in a direction away from the individual electrode 8, but the displacement plate 17 conversely moves downward. Since it is displaced in a convex shape, the upward displacement of the diaphragm 7 can be suppressed. This effect is the same when the external air pressure is higher than the internal pressure of the actuator chamber 24. As a result, the diaphragm 7 can always be held at a normal position regardless of changes in the external air pressure, and the volume of the actuator chamber 24 does not change, so that there is no variation in the ink discharge amount, and stable discharge characteristics can be obtained. It is done.

Since the pressure compensation chamber 16 is provided on the same reservoir substrate 4, it is possible to reduce the size of the inkjet head.
Since the displacement plate 17 is made of silicon, the dimensional accuracy is high.
Since the reservoir substrate 4 and the electrode substrate 3 are anodically bonded, the air tightness of the pressure compensation chamber 16 is high.

Next, the outline of the method for producing the ink jet head of the present invention will be described with reference to FIGS. 3 is a flowchart showing an example of the manufacturing process of the inkjet head of the present invention, FIG. 4 is an explanatory diagram of the manufacturing process of the cavity substrate, FIG. 5 is an explanatory diagram of the manufacturing process of the electrode substrate, and FIG. 6 is the manufacturing process of the reservoir substrate It is explanatory drawing.

First, a method for manufacturing the electrode substrate 3 will be described with reference to FIGS.
(Step 1) A glass substrate 300 having a thickness of about 1 mm is prepared, and both surfaces are polished.
(Step 2) On one surface of the glass substrate 300, gold / chrome is resist-patterned by photolithography as an etching mask 301 and etched with hydrofluoric acid to form a groove 31 for an individual electrode having a desired depth ( (See FIGS. 5A and 5B).
(Step 3) An ITO (Indium Tin Oxide) film 80 having a thickness of 100 nm is formed on the entire surface of the glass substrate 300 on which the groove 31 has been formed, for example, by sputtering (FIG. 5C).
Next, the ITO film 80 is subjected to resist patterning by photolithography, and the portions other than the individual electrodes are removed by etching to form the individual electrodes 8 in the grooves 31 (see FIG. 5D). When an insulating film is formed on the individual electrode 8, for example, a metal mask having an opening only on the individual electrode 8 is covered on the electrode substrate 3, and TEOS (Tetraethoxys) is formed.
ilane: Plasma CVD using tetraethoxysilane as a source gas
The r Deposition) method, may be formed of SiO ₂ film.
(Step 4) Next, for example, a dry film 302 is attached to the other surface of the glass substrate 300, and portions corresponding to the third reservoir 13 and the communication port 33 are subjected to resist patterning by photolithography (FIG. 5E). 3) by sandblasting
The through-opening 32 and the communication port 33 that serve as the reservoir 13 are formed (see FIG. 5F). Thereafter, the dry film 302 is peeled off (see FIG. 5G).
The wafer-like electrode substrate 3 is manufactured by the above process.

Next, a method for manufacturing the cavity substrate 2 will be described with reference to FIG.
As shown in FIG. 4A, for example, a silicon substrate 200 having a thickness of 280 μm is prepared,
Thermal oxide films 201 are formed on both surfaces, and portions corresponding to the recesses 21 for the discharge chamber and the second reservoir 12 are subjected to resist patterning by photolithography. At this time, a portion corresponding to the second reservoir 12 is patterned on the thermal oxide film 201 on both sides of the silicon substrate.
Next, as shown in FIG. 4B, the discharge chamber recess 21 having the bottom wall as the diaphragm 7 and the through opening 2 serving as the second reservoir 12 by anisotropic wet etching using a KOH aqueous solution.
2 are formed. Thereafter, the thermal oxide film 201 is peeled off (see FIG. 4C).
Finally, the surface of the silicon substrate 200, TEOS: forming by plasma CVD (Chemical Vapor Deposition) method using (Tetraethoxysilane tetraethoxysilane) as a source gas, a surface protective film made of SiO ₂ film (ink resistance protective film) To do. Further, when an insulating film is formed on the surface of the diaphragm 7 facing the individual electrode 8, an SiO ₂ film may be formed by plasma CVD as in the case of forming the surface protective film.

Next, a method for manufacturing the reservoir substrate 4 will be described with reference to FIG.
As shown in FIG. 6A, for example, a silicon substrate 400 having a thickness of 525 μm is prepared,
A thermal oxide film 401 having a thickness of about 1 μm is formed on both surfaces, and one thermal oxide film 401 is
The resist patterning is performed on the portion corresponding to the first-stage concave portion 41a to be the first reservoir 11 by photolithography.
Next, as shown in FIG. 6B, a second patterning is performed on the thermal oxide film 401 on the same surface, and a buffered hydrofluoric acid aqueous solution in which a hydrofluoric acid aqueous solution and an ammonium fluoride aqueous solution are mixed 1: 6. The portions corresponding to the second-stage recess 41b of the first reservoir 11 and the recess 42 of the pressure compensation chamber 16 are half-etched. The thermal oxide film 401 on the opposite surface is protected with a resist so as not to be etched.
Next, as shown in FIG. 6C, the third patterning is performed on the thermal oxide film 401 on the opposite surface, and the recesses 43 and 46 and the ink intake port 44 are formed with the same buffered hydrofluoric acid solution as described above.
Half-etch the portions corresponding to each of the above.
Next, as shown in FIG. 6 (d), a portion corresponding to the first step recess 41a is dug down by anisotropic wet etching using a KOH aqueous solution, and then, as shown in FIG. 6 (e),
The thermal oxide film 401 remaining in the second-stage recess 41b, recesses 42, 43, and 46 and the ink intake port 44 is removed by half-etching with a buffered hydrofluoric acid solution.
Next, as shown in FIG. 6 (f), a concave portion 41 to be the first reservoir 11, a concave portion 42 to be the pressure compensation chamber 16, a concave portion 43 on the back side thereof, by anisotropic wet etching with an aqueous KOH solution. 46 and the ink intake 44 are formed simultaneously. Thereby, the diaphragm 15 and the displacement plate 17 having a desired thickness are formed.
Finally, as shown in FIG. 6G, the thermal oxide film 401 is peeled off.
Further, when a surface protective film is required on both surfaces of the reservoir substrate 4, a thermal oxide film may be further formed.
Through the above process, the wafer-like reservoir substrate 4 is manufactured.

Again, as shown in FIG.
(Step 5) The wafer-like cavity substrate 2 and the electrode substrate 3 are aligned and anodic bonded. Thereby, the through opening 22 serving as the second reservoir 12 and the through opening 32 serving as the third reservoir 13 are directly connected.
(Step 6) Further, the wafer-like reservoir substrate 4 manufactured as described above is aligned with the opposite surface of the electrode substrate 3 on which the cavity substrate 2 has already been anodically bonded, and then anodic bonded. Thereby, the first reservoir 11 and the pressure compensation chamber 16 are defined between the electrode substrate 3 and the electrode substrate 3.
Here, in Step 5 and Step 6, if the cavity substrate 2 and the electrode substrate 3 and the electrode substrate 3 and the reservoir substrate 4 are aligned in advance, the cavity substrate 2 and the electrode substrate 3 are aligned.
Since the anodic bonding and the anodic bonding of the electrode substrate 3 and the reservoir substrate 4 can be performed continuously, the process can be simplified.
(Step 7) The chip driver IC 50 is mounted on the electrode substrate 3. It is assumed that the IC input wiring part 51 and the IC input terminal 52 are formed on the glass substrate of the electrode substrate 3 by sputtering.
(Step 8) The nozzle substrate 1 is bonded and bonded onto the surface of the cavity substrate 2 manufactured as described above. The nozzle substrate 1 is manufactured in a separate process. For example, a silicon substrate having a thickness of 180 μm is used, and the nozzle holes 5 are formed in the same number and at the same pitch as the plurality of discharge chamber recesses 21 by dry etching. . Then, surface treatment is performed and the nozzle substrate 1 is produced.
(Step 9) Then, it is divided into a plurality of head chips by dicing.
(Step 10) Finally, the FPC 60 is electrically connected to the head chip using a conductive adhesive, and the ink supply pipe 70 connected to the ink tank is connected to the connecting member 45.
Thus, the assembly of the ink jet head shown in this embodiment is completed.

According to this ink jet head manufacturing method, the following effects are obtained.
The first reservoir 11 and the displacement plate 17 can be manufactured simultaneously by wet etching.
Moreover, since it manufactures by wet etching, the 1st reservoir | reserver 11 and the displacement plate 17 can be formed with high precision and high quality.
Since the cavity substrate 2 and the electrode substrate 3 and the electrode substrate 3 and the reservoir substrate 4 can be continuously anodically bonded, the manufacturing is easy, the bonding strength is high, and the reliability is high.

In the above embodiment, the inkjet head and the manufacturing method thereof have been described.
The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the idea of the present invention. For example, the droplet discharge head according to the present invention can be used to manufacture color filters for liquid crystal displays, organic EL display devices in addition to the inkjet printer 100 as shown in FIG. 7 by changing the liquid material discharged from the nozzle holes. It can be used as a droplet discharge device for various uses such as formation of a light-emitting portion, production of a microarray of a biomolecule solution used for genetic testing and the like.

FIG. 2 is an exploded perspective view of a partial cross section illustrating a schematic configuration of the inkjet head according to the first embodiment of the invention. FIG. 3 is a partial cross-sectional view of an ink jet head in an assembled state. 5 is a flowchart showing an example of a manufacturing process of the inkjet head of the present invention. Explanatory drawing of the manufacturing process of a cavity board | substrate. Explanatory drawing of the manufacturing process of an electrode substrate. Explanatory drawing of the manufacturing process of a reservoir substrate. 1 is a schematic perspective view showing an example of an ink jet printer to which an ink jet head of the present invention is applied.

Explanation of symbols

1 Nozzle substrate, 2 Cavity substrate, 3 Electrode substrate, 4 Reservoir substrate, 5 Nozzle hole, 6 Discharge chamber, 7 Vibration plate, 8 Individual electrode, 10 Inkjet head, 11 1st
Reservoir, 12 second reservoir, 13 third reservoir, 15 diaphragm, 16
Pressure compensation chamber, 17 displacement plate, 18 ink supply port, 19 narrow groove, 21 recess, 22 through opening, 23 IC insertion port, 24 actuator chamber, 31 groove, 32 through opening, 33 communication port, 41 recess, 41a First step recess, 41b Second step recess, 41
c Stepped portion, 42 Recessed portion, 43 Recessed portion, 44 Ink intake port, 45 Connection member, 46
Concave part, 50 driver IC, 51 input wiring part, 52 FPC mounting terminal (IC input terminal), 60 FPC, 70 ink supply tube, 100 inkjet printer, 200 silicon substrate, 300 glass substrate, 400 silicon substrate.

Claims (8)

A nozzle substrate having a plurality of nozzle holes for discharging droplets;
A cavity substrate in which a bottom wall forms a vibration plate, and a recess serving as a discharge chamber is formed for each nozzle hole;
An electrode substrate formed with a plurality of individual electrodes facing the diaphragm and driving the diaphragm;
A reservoir substrate having a recess serving as a first reservoir for supplying droplets to the discharge chamber;
The nozzle substrate, the cavity substrate, the electrode substrate, and the reservoir substrate are stacked in this order,
The cavity substrate is provided with an opening serving as the second reservoir,
The electrode substrate is provided with an opening serving as a third reservoir,
The liquid droplet ejection head, wherein the recess serving as the first reservoir, the opening serving as the second reservoir, and the opening serving as the third reservoir communicate with each other. The droplet discharge head according to claim 1, wherein a diaphragm serving as the first reservoir is provided with a diaphragm. The droplet discharge head according to claim 1, wherein the reservoir substrate is provided with a displacement plate that can be displaced in accordance with a change in external air pressure. 4. The liquid droplet ejection head according to claim 1, wherein the reservoir substrate is made of silicon. 5. The liquid droplet ejection head according to claim 1, wherein the cavity substrate, the electrode substrate, and the reservoir substrate are laminated by anodic bonding. 6. The liquid according to claim 1, wherein the driver IC connected to the individual electrode is mounted on the same surface of the electrode substrate as the surface on which the individual electrode is formed. Drop ejection head. A droplet discharge apparatus comprising the droplet discharge head according to claim 1. Forming a plurality of nozzle holes in a silicon substrate and forming a nozzle substrate;
Forming a cavity substrate on a silicon substrate by forming a diaphragm with a bottom wall forming a plurality of recesses serving as discharge chambers and an opening serving as a second reservoir;
Forming a separate electrode for driving the diaphragm and an opening serving as a third reservoir on a glass substrate to obtain an electrode substrate;
Forming a recess serving as a first reservoir in a silicon substrate to obtain a reservoir substrate;
Have
The nozzle substrate, the cavity substrate, the electrode substrate, and the reservoir substrate are laminated in this order, and the cavity substrate and the electrode substrate, and the electrode substrate and the reservoir substrate are anodically bonded. A method for manufacturing a droplet discharge head.

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