JP2003266690A - Liquid drop discharge head and electrostatic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a liquid drop discharge head with a high yield which has a high reliability and a high ink discharge efficiency and is capable of high image quality printing. <P>SOLUTION: An electrostatic attraction is generated between electrodes 4a and 4b of a movable plate 5 by impressing a voltage between the electrodes, and the movable plate 5 is deformed by a slight displacement of electrodes 4, whereby liquid drops 12 are discharged. Since the movable plate 5 is electrically isolated from the electrodes 4, the voltage impressed to the electrodes 4 is prevented from leaking towards the movable plate 5. The voltage can be efficiently impressed to the electrodes 4. Although a short circuit is brought about to result in operation failures in some cases when small dust is laid on the electrodes or minute water drops are generated at surfaces of the electrodes 4 by a humidity of the air because a void between the electrodes is considerably minute, a withstand voltage can be improved and the operation failures due to the short circuit between electrodes can be reduced by setting an insulating film 26. <P>COPYRIGHT: (C)2003,JPO

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, a microactuator, a micropump, and an optical modulation device using electrostatic force, and for example, an inkjet recording device, a micropump used for transporting and transferring a minute flow rate of liquid. It can be applied to a projector, etc.

[0002]

2. Description of the Related Art An ink jet head, which is a liquid drop ejection head used in an ink jet recording apparatus used as an image recording apparatus such as a printer, a facsimile, a copying machine, or an image forming apparatus, has a nozzle for ejecting an ink droplet and a nozzle for ejecting the ink droplet. The pressure generated by the pressure generating means is provided with a communicating discharge chamber (also called a pressurized liquid chamber, a pressure chamber, an ink flow path, etc.) and a pressure generating means for generating a pressure for pressurizing the ink in the discharge chamber. The ink is ejected from the nozzle by pressurizing the ink in the ejection chamber.

In such a droplet ejection head, an electromechanical conversion element such as a piezoelectric element is used as a pressure generating means to deform and displace a movable plate forming a wall surface of an ejection chamber to eject an ink droplet. Piezo type, bubble type (thermal type) that generates bubbles by ink film boiling using an electrothermal conversion element such as a heating resistor arranged in the discharge to discharge ink droplets, and discharge chamber There is an electrostatic type in which a movable plate forming a wall surface is deformed by electrostatic force to eject ink droplets.

In recent years, lead-free bubble type and electrostatic type have attracted attention due to environmental problems, and many of the applicants are lead-free and electrostatic type, which has little influence on the environment from the viewpoint of low power consumption. Several types have been proposed.

For example, in the invention described in Japanese Patent Laid-Open No. 6-71882, a pair of electrodes is provided with a minute gap therebetween, and one electrode functions as a movable plate, which is opposite to the opposing electrode of the movable plate. The side is filled with ink. When a voltage is applied to the electrode pair, an electrostatic attractive force acts between the electrodes to deform the electrode (movable plate), and when the voltage is removed, the movable plate returns to its original state due to the elastic force, and the force is used to generate ink. Is discharged.

In this structure, the volume of ink droplets / the amount of deformation of the movable plate is mainly defined by the gap width between the electrodes facing each other and the movable plate area (the short side width and the long side width of the movable plate). / High-speed printing requires high density nozzles, and in that case, it is necessary to reduce the movable plate width / area. On the other hand, since the electrostatic force acting between the opposing electrodes is inversely proportional to the square of the gap width, it is necessary to reduce the gap width in order to bend the movable plate at a low voltage, and as a result, it is necessary to form an image. There is a problem that a sufficient ink droplet volume cannot be obtained.

In Japanese Patent Laid-Open No. 2000-15805, a large number of protrusions having electrodes formed on the surface are arranged on a movable plate,
A structure is proposed in which the movable plate is deformed by applying a voltage between the electrodes. With this configuration, it is possible to increase the displacement of the movable plate even if the width between the electrodes is reduced,
This is suitable for increasing the density of the nozzles.

[0008]

However, in this structure in which a plurality of protrusions / electrodes are formed on a thin movable plate, the probability that the movable plate / electrode protrusion will be damaged during manufacture if the movable plate / electrode protrusions are not protected. Higher and lower yield. In addition, the air gap between the electrodes is very narrow, so dust in the atmosphere will
If it adheres between the voids, the movement of the protrusion / movable plate will be restricted, ink ejection failure will occur, and the electrodes / movable plate will be damaged due to an electrical short circuit between the electrodes.

(Purpose of the Invention) The present invention has been made in view of the above-mentioned circumstances, and has a high yield of a droplet discharge head which has high reliability, high ink discharge efficiency, and high image quality printing. It is an object of the present invention to provide an ink jet recording apparatus which is manufactured and has this droplet discharge head, an ink cartridge in which the droplet discharge head is integrated, and the droplet discharge head.

[0010]

According to a first aspect of the present invention, there is provided a nozzle for ejecting a liquid droplet, and a pressurized liquid chamber communicating with the nozzle.
A movable plate that constitutes a part of the wall surface of the pressurized liquid chamber and a plurality of electrodes provided on the surface of the movable plate are provided, and the movable plate is deformed by an electrostatic force that acts between the electrodes. In a droplet discharge head that discharges droplets from a nozzle, a support protection substrate that protects the electrode is bonded to the surface of the movable plate on the side where the electrode is formed.

According to a second aspect of the invention, in the first aspect of the invention, a space is formed between the support / protective substrate and the electrode on the movable plate surface.

According to a third aspect of the present invention, in the first or second aspect of the invention, the space is formed by forming a step on the side of the support / protection substrate.

According to a fourth aspect of the invention, in the first or second aspect of the invention, the space is formed by forming a step on the substrate on the side where the electrodes are formed.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the joint portion of the support / protective substrate is formed in the electrode lead portion.

According to a sixth aspect of the invention, in the fifth aspect of the invention, the supporting and protective substrate is an insulating substrate.

The invention of claim 7 is characterized in that, in the invention of claim 5, an insulating layer is formed on the surface of the electrode lead portion and / or the support / protection substrate.

The invention of claim 8 is characterized in that, in the invention of claim 1 or 2, the space is formed by a patterned spacer formed between the supporting and protecting substrate and an electrode surface. Is.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the joint between the supporting and protecting substrate and the movable plate surface is formed so as to surround the outer periphery of the chip. It was done.

According to a tenth aspect of the present invention, in any one of the first to eighth aspects, the joint portion of the support / protection substrate is
It is characterized in that it is formed so as to surround the movable plate array.

According to an eleventh aspect of the present invention, in any one of the first to eighth aspects of the present invention, the joint portion of the support / protective substrate is
It is characterized in that it is formed so as to surround the bit.

According to a twelfth aspect of the present invention, in an ink cartridge in which an ink jet head for ejecting ink droplets and an ink tank for supplying ink to the ink jet head are integrated, the ink jet head is the first ink jet head.
The inkjet head according to any one of 1 to 13 above.

According to a thirteenth aspect of the present invention, in an ink jet recording apparatus equipped with an ink jet head for ejecting ink droplets, the ink jet head is the liquid droplet ejection head according to any one of the first to thirteenth aspects. It is what

According to a fourteenth aspect of the present invention, there is provided a micropump for transporting a liquid by deforming a movable plate, wherein at least two electrodes are provided on at least one surface of the movable plate,
It is characterized in that the movable plate is deformed by an electrostatic force acting between these electrodes.

According to a fifteenth aspect of the present invention, there is provided an optical modulation device which changes a reflection direction of light by deforming a mirror.
The mirror is deformed by deformation of the movable plate, at least two electrodes are provided on at least one surface of the movable plate, and the movable plate is deformed by electrostatic force acting between the electrodes.

[0025]

1 is an exploded perspective view of a droplet discharge head according to a first embodiment of the present invention, which is a partial cross-sectional view. This embodiment shows an example of a side shooter type in which ink droplets are ejected from nozzle holes provided on the surface of the substrate. FIG. 2 shows a cross-sectional view of the assembled whole apparatus, and for convenience sake, only two discharge chambers are shown. The inkjet head of this embodiment has a laminated structure in which three substrates 1, 2 and 3 having a structure described in detail below are stacked and joined.

The intermediate first substrate 1 is a silicon substrate, and a discharge chamber 6 whose bottom wall is a movable plate 5 and each discharge chamber 6
It has a common liquid chamber 10 for supplying ink. A plurality of electrodes 4 are formed on the lower surface of the movable plate 5, and the movable plate 5 and the electrodes 4, and the adjacent electrodes 4a and 4b are electrically separated. In FIG. 2, the movable plate 5 and the electrode 4 are
An insulating film 21 is formed between them. FIG. 3 shows the substrate 1
Electrode 4 for one movable plate when viewed from the electrode 4 side
This is an example of the shape of the above, and different potentials are applied to the adjacent electrodes 4a and 4b.

The second substrate 2 bonded to the lower surface of the first substrate 1 is used during the manufacture of the inkjet head, and, for example,
This is a support / protection substrate for preventing the electrode 4 and the movable plate 5 from being damaged when mounted on an inkjet printer or the like, and for reinforcing the strength of the substrate 1. Substrate 1 in which discharge chamber 6 is formed
Is preferably 100 μm or less from the viewpoint of ink ejection efficiency, and is very easily damaged by the substrate 1 alone, but by bonding the supporting / protecting substrate 2 having a certain strength, handling during manufacturing is easy. become. In addition, since the movable plate and the electrodes are sometimes formed on the order of submicron, they are also easily damaged, and the surface on which the electrodes are
By joining the support / protection substrate 2, the electrode surface is prevented from coming into direct contact with the work surface.

Further, the gap between the electrodes 4a and 4b is 1 μm.
Since it is very narrow below, the displacement between the electrodes is obstructed when atmospheric dust enters the void. By sealing the part surrounded by the electrode part and the support / protective substrate with a separate member, dust in the electrode part can be suppressed. As the material of the support / protection substrate 2, a substrate made of glass, metal, silicon, resin, ceramics, or the like is used. The support / protection substrate 2 is provided with recesses 7 at positions corresponding to the respective electrodes / movable plates. There is. The recess 7 is formed in order to prevent the electrode 4 from being damaged by the substrate 2 coming into contact with the electrode 4 on the substrate 1 when the substrate 1 and the substrate 2 are bonded together.

As the third substrate 3 bonded to the upper surface of the first substrate 1, a nickel substrate having a thickness of 50 μm is used, and the surface of the substrate 3 is provided with nozzle holes 8 so as to communicate with the discharge chamber 6. A groove 9 serving as a fluid resistance that connects the common liquid chamber 10 and the ejection chamber 6 is provided, and an ink supply port 11 is provided so as to communicate with the common liquid chamber 10.

Next, the operation of the droplet discharge head configured as described above will be described. 0V to the electrode 4a by the oscillation circuit
When a pulse potential of 40 V is applied to the electrode 4a and the surface of the electrode 4a is positively charged, the electrode 4 not applied with the pulse potential
The movable plate 5 bends upward due to the electrostatic attraction between it and b. As a result, the pressure in the ejection chamber 6 rapidly rises, and the ink droplets 12 are ejected from the nozzle holes 8 toward the recording paper 13. Next, when the potential of the electrode 4a returns to 0V, the electrode 4b
And the potential difference disappears, and the movable plate 5 is restored. When the movable plate 5 is restored, ink is replenished from the common liquid chamber 10 into the ejection chamber 6 through the fluid resistance path 9.

In the droplet discharge head of the present invention, the electrode 4 of the movable plate 5 is formed, and by applying a voltage between the electrodes 4a and 4b, an electrostatic attractive force is generated between the electrodes 4a and 4b. A large displacement of the movable plate 5 can be obtained by a slight displacement of the electrode 4. Since the movable plate 5 and the electrode 4 are electrically separated, the voltage applied to the electrode 4 does not leak to the movable plate 5 side, and the voltage can be efficiently applied to the electrode 4. Here, the insulating film 21 is formed between the movable plate 5 and the electrode 4 as an example of electrically separating the movable plate 5 and the electrode 4.

An insulating film 26 may be provided on the surface of the electrode 4 as shown in FIG. As described above, the gaps between the electrodes are very small, so if small dusts are placed on the electrodes or minute water droplets are generated on the surface of the electrode 4 due to the humidity of the air, it may cause a short circuit and malfunction. Wake up. In addition, a discharge may occur between the electrodes when a voltage is applied, which may cause a malfunction. By providing the insulating film 26, the withstand voltage can be improved and the malfunction due to the short circuit between the electrodes can be reduced.

(Embodiment 1) FIG. 5 is a main part configuration diagram for explaining one embodiment of the present invention. In this embodiment, a spacer 25 is provided with the same material as the electrode 4. The spacer 25 is formed simultaneously with the electrode 4, and can be formed without removing the electrode material other than the movable plate region. The spacer 25 plays a role of protecting the electrode 4 which is a minute structure in a process before the substrate 1 is bonded to the substrate 2, and reduces defects due to wafer transfer in the manufacturing process and damage of the electrode 4 during the process. it can.
In the joining of the substrate 1 and the substrate 2, in order to prevent the substrate 2 from coming into contact with the electrode 4, the substrate 2 is provided with a recess 7 corresponding to the electrode / movable plate. The recess 7 may be formed so as to penetrate the substrate 2 as shown by 7'in FIG.

(Embodiment 2) FIGS. 7 to 9 are views for explaining a manufacturing process of the droplet discharge head having the structure shown in FIG. 6, and in this embodiment, the electrode 4 is formed of a polysilicon film. (Polycrystalline silicon).

(A): Thickness 4 with (110) as the plane orientation
The silicon substrate 14 having a thickness of 00 μm is used as the base substrate, and the thickness of the silicon having the (100) plane orientation is 1 μm with the oxide film 15 interposed therebetween.
SOI (Silicon on) including the active layer 16 of
An Insulator wafer 17 is prepared. (B): A thermal oxide film 18 having a thickness of 50 nm is formed by wet oxidation at 900 ° C. for 5 minutes. Here, as a method for forming the oxide film, there are plasma CVD, sputtering, HTO, TEOS and the like, but a thermal oxide film is preferable in terms of withstand voltage, defects, residual charges, durability and the like. In addition to the silicon oxide film, a silicon nitride film formed by LPCVD or the like can be applied. As with the thermal oxide film, it has high withstand voltage and tensile film stress, so that buckling of the movable plate does not occur.

(C): A 5 μm thick polysilicon film is formed on the surface, and the upper polysilicon layer is removed by etching. Further, the surface of the lower polysilicon layer 19 is polished by CMP. (D): A resist pattern is formed on the polysilicon layer 19 by photolithography, and the polysilicon is etched by dry etching with a line width of 1 μm and 0.5 μm to form the electrode 4. At this time, the oxide film 18 forms an etching stop layer. The shape of the electrode 4 is, for example, a comb tooth shape.

(E): A BSG film is formed to a thickness of 0.1 μm on the silicon substrate 2 which is a supporting and protective substrate having a concave portion 7 and a thermal oxide film formed on the surface in advance, and the electrode 4 is formed. After pre-bonding the thus-formed silicon substrate 14 at room temperature, it is heated at 1000 ° C. for 2 hours to be bonded. (F): The substrate 14 is polished to a thickness of 100 μm by a polishing method such as polishing or grinding. (G): A silicon nitride film 20 serving as a mask for potassium hydroxide etching is formed by LP-CVD. A resist pattern having a shape such as the discharge chamber 6 or the common liquid chamber 10 is obtained on the silicon nitride film 20. Next, the silicon nitride film 20 in the opening of the resist is removed by etching by dry etching, and then the resist is removed to obtain a mask pattern of the silicon nitride film.

(H): The silicon nitride film 20 and the silicon substrate 1 were formed with a 25 wt% potassium hydroxide aqueous solution at 80 ° C.
Etch 4 openings. Etching is oxide film 15
When the temperature reaches, the oxide film is hardly etched and the etching stops. In this embodiment, since the (110) plane silicon wafer is used as the base substrate (silicon substrate) 14, the (111) plane vertical wall is formed by anisotropic etching with potassium hydroxide. (110)
Since the vertical wall is obtained by using the surface wafer, the discharge chambers can be arranged in high density. Although an aqueous solution of potassium hydroxide is used here, an alkaline solution such as TMAH (tetramethylammonium hydroxide solution), EDP (ethylenediaminepyrocatechol) or lithium hydroxide may be used. (I): After that, the silicon nitride film 20 is removed by hot phosphoric acid, hydrofluoric acid or the like, and the exposed portions of the thermal oxide film 18 and the oxide film 15 are removed by hydrofluoric acid or the like.

(Embodiment 3) FIG. 10 is a view for explaining another embodiment of the present invention. This embodiment is an improved version of Embodiment 1, in which the thickness of the spacer 25 is different from that of the electrode 4. The recess 7 between the electrode 4 and the support / protection substrate 2 is formed to be larger than the thickness. With this structure,
There is an advantage that the concave portion may not be formed in the supporting and protecting substrate 2 below the substrate 1, and the probability that the electrode 4 comes into contact with the protecting substrate by the spacer 25 and is damaged as compared with the first embodiment is reduced. It is possible to reduce defects due to breakage. It is also possible to join the supporting and protective substrate 2 without forming an alignment pattern.

(Embodiment 4) FIGS. 11 to 13 are views for explaining a process of manufacturing a droplet discharge head having the structure shown in FIG. 10. In this embodiment, the electrode 4 is made of single crystal silicon. ing. The movable plate 5 in the ink jet head of this embodiment is a high-concentration p-type impurity layer, and the high-concentration p-type impurity layer has a thickness equal to a desired movable plate thickness, in this case 1
μm.

(A): Thickness 4 with the plane orientation of (110)
Boron is diffused in a silicon substrate 21 of 00 μm by an ion implantation method to form a high concentration boron diffusion layer 22. Here, a high-concentration boron diffusion layer having a depth of 1 μm was formed. A compound layer of silicon and boron is formed on the surface of the high-concentration boron diffusion layer. This layer can be removed by thermal oxidation of the compound layer and etching with a hydrofluoric acid-based etching solution. Roughness may occur on the surface where the silicon is diffused, and a strong bond may not be obtained in the subsequent direct bonding. Therefore, the high-concentration boron diffusion layer 22 is polished to form a smooth surface. (B): 900 ° C. after removing the compound layer and polishing
A thermal oxide film 23 having a thickness of 50 nm is formed by wet oxidation for / 5 minutes. Here, plasma C is used as a method for forming the oxide film.
Although there are VD, sputter, HTO, TEOS, etc., a thermal oxide film is preferable in terms of withstand voltage, defects, residual charge, durability and the like.

(C): Prepare another silicon substrate 24,
The silicon substrate 24 is directly bonded to the high-concentration boron diffusion layer 22 side. Here, a silicon wafer having a (100) plane orientation was used. The two wafers are firmly bonded by sticking together a silicon wafer having a good surface property and heating it at a high temperature. Here, heat treatment was performed at 1000 ° C./2 hours. (D): CMP polishing the silicon substrate 24 to a thickness of 20 μm. Subsequently, the recess 7 is formed in the portion where the electrode / movable plate is formed.

(E): A resist pattern is formed in the concave portion 7 of the silicon substrate 24 polished by photolithography, and the silicon substrate 24 is spaced by 0.5 μm by dry etching.
By etching with a line width of m and a width of 0.5 μm, another concave portion 57 which becomes a part of the electrode 4 and the opening is formed. The shape of the electrode 4 is, for example, a comb tooth shape. In the etching, the thermal oxide film 23 serves as a stop layer. Since it is necessary to finely etch very deep grooves, dry etching is
CP is effective.

FIG. 14 shows the chip shape of this embodiment in a plan view after the electrodes are formed. The portion bordered by the solid line 54 shows the surface to be joined to the supporting and protective substrate, and the wavy line 55 shows. The part shown corresponds to the electrode on the movable plate, corresponds to the recess 7, and the thickness of the silicon substrate 24 is thin.

Furthermore, when forming the slits between the electrodes,
Also, a connection path 58 for connecting each bit and connecting to an opening 60 (described later) formed through the silicon substrates 21 and 24 to open the recess of each bit to the atmosphere is also formed. An electrode lead-out portion 59 for applying a voltage to the electrodes is also formed at the same time.

(F): The unpatterned silicon substrate 2 having the thermal oxide film formed on its surface and the silicon substrate 24 having the electrodes 4 formed thereon are prebonded under reduced pressure, and then 1000 again.
Bonding is performed by heat treatment at ° C / 2 hours. (G): The silicon substrate 21 is polished to a thickness of 100 μm by a polishing method such as polishing or grinding. Then, a silicon nitride film 20 serving as a mask for potassium hydroxide etching is formed by LP-CVD. Then, the discharge chamber 6, the common liquid chamber 10 and the opening 6 are formed on the silicon nitride film 20.
A resist pattern having a shape of 0, the electrode extraction opening 61, etc. is obtained. Next, the silicon nitride film 20 in the opening of the resist is removed by etching by dry etching, and the resist is removed to obtain a silicon nitride film pattern.

In the configuration of this embodiment, the electrode lead-out portion 59
Are bonded to the support / protection substrate 2. Therefore, the electrode can be taken out from the discharge chamber side, and the electrode lead-out port can be formed at the same time when the discharge chamber and the common liquid chamber are formed. However, for the purpose of preventing electrical crosstalk between bits via the support / protection substrate 2, it is preferable to use, as the substrate 2, a substrate such as glass or ceramic which itself has an insulating property. When a conductive silicon substrate is used as in this embodiment, it is necessary to thicken an insulating film such as an oxide film or a nitride film to reduce the capacitance of the support substrate and the electrode extraction portion. Reducing the capacitance can also be achieved by forming an insulating film on the bonding surface on the electrode side.

(H): Immediately before reaching the high-concentration boron diffusion layer 22 through the openings of the silicon nitride film 20 and the thermal oxide film 23 with a 25 wt% potassium hydroxide aqueous solution at 80 ° C. (remaining 1
Etching is performed up to about 0 μm. Next, the etching solution was changed to a 30 wt% potassium hydroxide aqueous solution at 80 ° C. in which IPA was supersaturated, and etching was continued,
When reaching the high-concentration boron diffusion layer 22, etching spontaneously stops. A 25 wt% aqueous solution of potassium hydroxide has a high etching rate and stable etching can be obtained. Further, in the 30 wt% potassium hydroxide aqueous solution to which IPA is added, the etching selection ratio between the silicon substrate and the high-concentration boron layer is large, and the etching can be stopped accurately. I
Since PA has a low boiling point and evaporates significantly when heat is applied, it is preferable to attach a reflux device for cooling the vapor to liquefy it and returning it to the etching tank. As an etchant capable of increasing the etching selection ratio of the high-concentration boron diffusion layer, potassium hydroxide aqueous solution having a low concentration of about 3 wt% to 10 wt% or EDP may be used other than potassium hydroxide added with IPA.

(I): Thereafter, the silicon nitride film 20 is removed with hot phosphoric acid, hydrofluoric acid or the like, and the thermal oxide film 23 is removed with hydrofluoric acid or the like. (J): The depression 7 in a depressurized state is opened to the atmospheric pressure through the opening 60, and the external power source and the electrode lead-out portion 59 are connected through the electrode take-out opening 61. After protecting the liquid chamber portion with the quartz mask 62, the silicon thin film and the oxide film portion which are the movable plate layers are removed by dry etching.

FIG. 15 shows a schematic top view from the discharge chamber side after dry etching corresponding to the electrode schematic plan view of FIG. Since the electrode 4 is made of single crystal silicon and the thickness of the electrode 4 can be determined by polishing after bonding the wafers, a thick electrode that cannot be formed by film formation can be formed. If the electrodes are thick (high in height), the movable plate can be deformed with a small force and can be driven at a low voltage. It is also possible to integrate the drive circuit of the droplet discharge head by utilizing the region of the bonded silicon substrate 24 which is not used as an electrode. Since the silicon substrate 24 itself is used for forming a semiconductor element, it is suitable for forming a drive circuit.

In this embodiment, since the electrode portion is not exposed to wet etching, the probability that foreign matter will enter the gap between the electrodes is reduced. Further, since the thin movable plate is not exposed to the etching solution on both sides, the probability of damage during the wet process can be reduced.

Further, in the fourth embodiment, the communication passage is formed on the electrode member side. However, when the concave portion is formed on the supporting and protecting substrate side as in the first and second embodiments, it is formed on the supporting and protecting substrate side. Is also good. Further, although the electrode outlet 61 and the opening 57 are formed on the substrate on which the electrodes and the discharge chamber are formed, they may be formed on the side of the support / protection substrate 2 as shown in FIG.

(Embodiment 5) FIG. 17 is a cross-sectional view of a main part for explaining another embodiment of the present invention. In Embodiments 1 to 4, a space formed between an electrode and a support / protective substrate is In contrast to the case where the electrode member and the support / protective substrate are provided with the concave portions, in this embodiment, the patternable members are sandwiched between the members without forming the concave portions. Is simplified. For example, when a dry film resist or a photosensitive resin is used for the spacer member 66, patterning and etching processes are usually required, but it can be formed only by photolithography. When an organic material is used for the spacer, the silicon nitride film cannot be formed as an etching mask as in Examples 2 and 4, but can be formed by dry etching such as ICP using a resist as a mask. Of course, the spacer may be formed by patterning and then etching the electrode member or the film formed on the supporting and protecting substrate.

(Embodiment 6) FIGS. 18A and 18B are views for explaining another embodiment of the present invention. FIG. 18A shows a chip outer circumference 71, FIG. 18B shows a movable plate array outer circumference 72, and FIG. (C) is a joint 7 between the support / protection member and the electrode / vibration plate member for each bit 75
3 shows the case where 3 is formed together with the projected electrode / movable plate position. As shown in FIGS. 18A and 18B, when a bonding portion is provided on the chip outer periphery 71 or the movable plate array outer periphery 72, a recess 74 is formed in the support protection member as in the first and second embodiments, for example. In this case, the process cost can be suppressed because alignment accuracy is not required so much. Further, even when a conductive substrate such as a silicon substrate is used as the support / protection substrate, the ready-made capacitance with the electrode / movable plate member can be reduced. When a metal or ceramics such as a nickel plate is used for the nozzle plate, the coefficient of thermal expansion is greatly different from that of a silicon substrate that can be used for the electrode / discharge chamber member and the support / protection substrate, and therefore bonding strength is required. ), The joint strength can be increased when the joint portion 73 is provided for each bit 75.

(Embodiment 7) FIG. 19 is a diagram for explaining a recording head according to the present invention.
The inkjet head 81 according to any one of the above-described embodiments having the nozzle holes 8 and the like, and the inkjet head 8
The ink tank 82 for supplying the ink to the unit 1 is integrated. As described above, in the case of the head integrated with the ink tank, the cost reduction and reliability of the head immediately lead to the cost reduction and reliability of the entire ink cartridge. Becoming
By reducing manufacturing defects, the yield and reliability of the ink cartridge can be improved, and the cost of the head-integrated ink cartridge can be reduced.

(Embodiment 8) Next, an example of an ink jet recording apparatus equipped with an ink jet head according to the present invention will be described with reference to FIGS. 20. FIG. 20 is a perspective explanatory view of the recording apparatus, and FIG. 21 is a side view of a mechanical portion of the recording apparatus. This inkjet recording apparatus includes a carriage movable in the main scanning direction inside a recording apparatus main body 90, a recording head including an inkjet head according to the present invention mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. The printing mechanism unit 91 and the like constituted by are housed, and a paper feed cassette (or a paper feed tray) 84 capable of loading a large number of papers 83 from the front side is detachably attached to the lower portion of the apparatus main body 90. Further, the manual feed tray 85 for manually feeding the paper 83 can be opened, the paper 83 fed from the paper feed cassette 84 or the manual feed tray 85 can be taken in, and the printing mechanism unit 91 can be used. After recording a desired image by, the paper is discharged to the paper discharge tray 86 mounted on the rear surface side.

The printing mechanism portion 91 slides the carriage 93 in the main scanning direction (the direction perpendicular to the paper surface in FIG. 21) by the main guide rod 92a and the sub guide rod 92b which are guide members which are horizontally mounted on the left and right side plates (not shown). A plurality of recording heads 94, each of which is an ink jet head according to the present invention, which is freely held and ejects ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) on the carriage 93. The ink ejection ports (nozzles) are arranged in a direction intersecting the main scanning direction, and the ink droplet ejection direction is attached downward. Further, each ink cartridge 95 for supplying each color ink to the recording head 94 is replaceably mounted on the carriage 93.

The ink cartridge 95 has an atmosphere port communicating with the atmosphere above, a supply port supplying ink to the ink jet head below, and a porous body filled with ink inside. The ink supplied to the inkjet head is maintained at a slight negative pressure by the capillary force of. Further, although the recording heads 94 of the respective colors are used as the recording heads here, one head having nozzles for ejecting ink droplets of the respective colors may be used.

Here, the carriage 93 is slidably fitted to the main guide rod 92a on the rear side (downstream side in the sheet conveying direction) and slidably fitted to the sub guide rod 92b on the front side (upstream side in the sheet conveying direction). It is placed in. Then, in order to move and scan the carriage 93 in the main scanning direction, a drive pulley 98 and a driven pulley 9 which are rotationally driven by a main scanning motor 97.
9, a timing belt 100 is stretched between the carriage 9 and the carriage 93, and the carriage 93 is fixed to the timing belt 100.
Is driven back and forth.

On the other hand, in order to convey the paper 83 set in the paper feed cassette 84 to the lower side of the recording head 94, the paper feed roller 1 for separating and feeding the paper 83 from the paper feed cassette 84.
01 and friction pad 102, a guide member 103 for guiding the paper 83, a transport roller 104 for inverting and transporting the fed paper 83, and the transport roller 10.
A transport roller 105 pressed against the peripheral surface of the sheet No. 4 and a leading end roller 106 that regulates the delivery angle of the sheet 83 from the transport roller 104 are provided. The conveyance roller 104 is rotationally driven by the sub-scanning motor 107 via a gear train.

A print receiving member 109, which is a paper guide member for guiding the paper 83 sent out from the conveying roller 104 below the recording head 94 in correspondence with the moving range of the carriage 93 in the main scanning direction, is provided. There is. At the downstream side of the print receiving member 109 in the sheet conveying direction, the conveying roller 11 that is rotationally driven to send out the sheet 83 in the sheet discharging direction.
1, the spur 112 is provided, and the paper 83 is further ejected to the paper ejection tray 8
A sheet discharge roller 113 and a spur 114 that are sent to the sheet 6, and guide members 115 and 116 that form a sheet discharge path are arranged.

At the time of recording, by driving the recording head 94 in accordance with the image signal while moving the carriage 93, ink is ejected onto the stopped paper 83 to record one line, and the paper 83 is moved by a predetermined amount. After transportation, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the sheet 83 has reached the recording area, the recording operation is terminated and the sheet 83 is discharged.

A recovery device 117 for recovering the ejection failure of the head 94 is arranged at a position outside the recording area on the right end side of the carriage 93 in the moving direction. The recovery device 117 has a cap means, a suction means, and a cleaning means. The carriage 93 is moved to the recovery device 117 side during printing standby, the recording head 94 is capped by the capping means, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant, and stable ejection performance is maintained.

When an ejection failure occurs or the like, the ejection port (nozzle) of the recording head 94 is sealed by the capping means, and the bubbles and the like are sucked out from the ejection port by the suction means through the tube and adhered to the ejection port surface. Ink, dust, etc. are removed by the cleaning means and the ejection failure is recovered. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed in the lower portion of the main body, and is absorbed and held by an ink absorber inside the waste ink reservoir.

As described above, since this ink jet recording apparatus is equipped with the ink jet head embodying the present invention, there is no ink droplet ejection failure due to defective driving of the movable plate, and stable ink droplet ejection characteristics can be obtained. Image quality is improved. Further, since a head that can be driven at a low voltage is mounted, the power consumption of the entire inkjet recording device can be reduced. Although the present invention is applied to the inkjet head in the above-described embodiments, the present invention can also be applied to a droplet ejection head that ejects droplets other than ink, for example, a liquid resist for patterning.

(Embodiment 9) FIG. 22 is an application of the droplet discharge head according to the present invention to a micropump, and the operation principle thereof will be described with reference to FIG. As shown, a plurality of movable plates 5 provided with electrodes 4 are provided, and the flow path 3
The structure is such that the fluid flows through the inside of 1. By sequentially driving the movable plate 5 from the right side in the figure, the fluid in the flow path 31 flows in the direction of the arrow, and the fluid can be transported. In this embodiment, an example in which a plurality of movable plates are provided has been shown, but the number of movable plates may be one, and a valve or the like may be provided in order to improve transportation efficiency.

(Embodiment 10) FIG. 23 shows an application of the droplet discharge head according to the present invention to an optical device.
As shown in, a plurality of movable plates 5 provided with the electrodes 4 are arranged, and the movable plates 5 also serve as mirrors. A dielectric multilayer film or a metal film may be formed on the surface of the movable plate 5 to increase the reflectance. Light from the light source 32 is applied to the movable plate (mirror) 5 via the lens 33. Movable plate (mirror)
If 5 is not driven, the light will be reflected at the same angle as the angle of incidence. When the movable plate (mirror) 5 is driven, since the movable portion serves as a convex mirror, the reflected light becomes divergent light and is not projected through the projection lens 34, and thus the light modulation device can be realized by the present invention.

FIG. 24 shows an example in which the optical device shown in FIG. 23 is applied. Light from the light source 32 is applied to the movable plate (mirror) 5 through the lens 33, and the movable plate (mirror) is irradiated.
The light incident on the part where 5 is not driven enters the projection lens 34. On the other hand, a voltage is applied to the electrode 4 to deform the movable plate (mirror) 5 (movable part) becomes a convex mirror, so that light diverges and hardly enters the projection lens 34. The light incident on the projection lens 34 is projected on a screen (not shown) or the like. An image can be displayed on the screen by arranging this structure two-dimensionally as shown in FIG. 24 and driving each movable part independently. In FIG. 24, an example in which 4 × 4 movable parts are arranged is shown as an example, but a larger number can be arranged, and the number is not limited to this.

In the ninth and tenth embodiments, the operating principle is briefly described, but the manufacturing method and structure shown in the first to sixth embodiments can be applied to the ninth and tenth embodiments. Although the configuration of the present invention has been described by taking the droplet discharge head, the micro pump, and the optical modulation device as an example, the present invention can be applied to other optical devices, micro actuators, and the like. In the embodiment described above, the electrode 4 is separated only in one direction. However, as shown in FIG. 25, the electrode 4 is separated in a grid pattern so that the movable plate 5 is biaxial. It may be deformed.

[0070]

EFFECTS OF THE INVENTION By supporting a thin substrate on which a discharge chamber is formed so as to protect the surface on which an electrode and a movable plate that are easily destroyed are protected, it is possible to improve the yield and to support it. By sealing the space formed by the protective substrate and the electrode portion, it is possible to prevent dust and moisture from entering the minute gap between the electrodes, and prevent deformation of the movable plate.

By forming a space between the electrode and the support / protection substrate, it is possible to prevent destruction and adsorption of the electrode portion when the substrate on which the electrode is formed and the support / protection substrate are bonded. it can.

By forming the concave portion in the support / protection substrate in advance, a space for preventing damage at the time of bonding can be formed.

By making the thickness of the electrode member on the movable plate, which is to be the electrode, smaller than that of the surrounding area, the height of the electrode portion is always lower than that of the joint surface, and damage during the joint can be further suppressed.

By forming a spacer that is a member separate from the electrode member and the support / protection substrate, a photosensitive organic material or the like can be used, and a space for preventing breakage can be formed by a simpler process.

By making the electrode lead-out surface a joint surface with the support / protective substrate, the electrode can be led out from the discharge chamber side, and the electrode lead-out port can be formed by etching simultaneously with the discharge liquid chamber, the common liquid chamber, and the like. Therefore, the manufacturing process can be simplified.

By making the supporting and protective substrate an insulating substrate,
By reducing the coupling between the electrode lead-out portion and the support / protection substrate, suppressing crosstalk between bits, and reducing the capacitance of the entire head, it is possible to achieve high-speed response drive and low power consumption.

By forming an insulating film between the support / protective substrate and the electrode lead-out portion, crosstalk between bits can be easily suppressed.

By forming the joint between the electrode member and the support / protective substrate on the outer periphery of the chip, the joint alignment is facilitated and the coupling capacitance between the electrode member and the support / protective substrate can be reduced.

By forming the joint between the electrode member and the support / protective substrate on the outer periphery of the diaphragm array, the joint alignment is facilitated, and the coupling capacity between the electrode member and the support / protective substrate is reduced, while the joint strength is increased. Can be increased.

By forming a joint between the electrode member and the support / protective substrate on the outer periphery of each bit, the joint strength can be made extremely strong, and a wide choice of other constituent members such as the nozzle plate can be taken. Therefore, it becomes possible to easily reduce the cost and improve the yield.

Since the ink jet head, which is the droplet discharge head according to the present invention, and the ink tank for supplying the ink to the ink jet head are integrated, manufacturing defects can be reduced and the cost can be reduced.

According to the ink jet recording apparatus of the present invention, since any one of the ink jet heads of the present invention is mounted, the manufacturing defects can be reduced and the cost can be reduced.

Since the movable plate is deformed by the electrostatic force acting between the electrodes, a micropump having a small size and low power consumption can be realized.

Since the movable plate is deformed by the electrostatic force acting between the electrodes, it is possible to realize a small size and low power consumption optical modulation device.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a droplet discharge head according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the assembled whole device.

FIG. 3 is a diagram showing an example of the shape of an electrode with respect to a movable plate when the substrate is viewed from the electrode side.

FIG. 4 is a diagram showing an example in which an insulating film is provided on a surface of an electrode.

FIG. 5 is a main part configuration diagram for explaining another embodiment of the present invention.

FIG. 6 is a diagram showing an example in which a recess is formed so as to penetrate the substrate.

FIG. 7 is a diagram for explaining a manufacturing process of the droplet discharge head having the configuration shown in FIG.

FIG. 8 is a diagram for explaining a process that follows the manufacturing process of the droplet discharge head having the configuration shown in FIG.

FIG. 9 is a diagram for explaining a further subsequent process of the manufacturing process of the droplet discharge head having the configuration shown in FIG. 6;

FIG. 10 is a diagram for explaining another embodiment of the present invention.

FIG. 11 is a diagram for explaining a manufacturing process of the droplet discharge head having the configuration shown in FIG.

FIG. 12 is a diagram for explaining a process that follows the manufacturing process of the droplet discharge head having the configuration shown in FIG.

FIG. 13 is a diagram for explaining still another process following the manufacturing process of the droplet discharge head having the configuration shown in FIG.

FIG. 14 is a diagram showing the chip shape of the present example in a plan view after electrode formation.

15 is a schematic top view from the ejection chamber side after dry etching corresponding to the electrode plan view shown in FIG.

FIG. 16 is a diagram showing an example in which an electrode tap is formed on the side of a support / protection substrate.

FIG. 17 is a cross-sectional configuration diagram of main parts for explaining another embodiment of the present invention. It is a figure which shows the example of the junction part of a support holding electrode and an electrode / diaphragm member.

FIG. 18 is a diagram for explaining another embodiment of the present invention.

FIG. 19 is a perspective view for explaining a recording head according to the present invention.

FIG. 20 is a perspective view of a recording apparatus according to the present invention.

FIG. 21 is a side view illustrating a mechanism portion of the recording apparatus according to the present invention.

FIG. 22 is a diagram showing an example in which the droplet discharge head according to the present invention is applied to a micro pump.

FIG. 23 is a diagram showing an example in which the droplet discharge head according to the present invention is applied to an optical device.

FIG. 24 is a diagram showing an application example of the optical device shown in FIG. 23.

FIG. 25 is a diagram showing an example in which electrodes are separated into a grid shape and a movable plate is deformed biaxially.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 2 ... Support protective substrate, 3 ... Nickel substrate, 4, 4a, 4b ... Electrode, 5 ... Movable plate, 6 ... Discharge chamber,
7 ... Recessed portion, 8 ... Nozzle hole, 9 ... Fluid resistance path, 10 ... Common liquid chamber, 11 ... Ink supply port, 12 ... Ink droplet, 13 ...
Recording paper, 14 ... Silicon substrate, 15 ... Oxide film, 16 ... Active layer, 17 ... SOI wafer, 18 ... Thermal oxide film, 19 ... Polysilicon layer, 20 ... Silicon nitride film, 21 ... Insulating film,
22 ... High concentration boron diffusion layer, 23 ... Thermal oxide film, 24 ... Silicon substrate, 25 ... Spacer, 26 ... Insulating film, 31 ... Flow path, 32 ... Light source, 33, 34 ... Lens, 57 ... Opening port,
58 ... Connection path, 59 ... Electrode take-out part, 60 ... Opening port, 6
DESCRIPTION OF SYMBOLS 1 ... Electrode extraction port, 62 ... Quartz mask, 66 ... Spacer member, 71 ... Chip outer periphery, 72 ... Movable plate arrangement outer periphery, 73
... Joining portion, 74 ... Recessed portion, 75 ... Bit, 80 ... Recording head, 81 ... Inkjet head, 82 ... Ink tank, 83 ... Paper, 84 ... Paper feed cassette, 85 ... Manual feed tray, 86 ... Paper ejection tray, 90 ... Recording device main body, 91 ...
Printing mechanism portion, 92a ... Main guide rod, 92b ... Sub guide rod, 93 ... Carriage, 94 ... Recording head, 95
Ink cartridge, 97 ... Main scanning motor, 98 ... Drive pulley, 99 ... Followed pulley, 100 ... Timing belt, 101 ... Paper feed roller, 102 ... Friction pad, 103 ... Guide member, 104 ... Conveying roller, 105
... conveyance roller, 106 ... front end roller, 107 ... sub-scanning motor, 109 ... printing receiving member, 111 ... conveyance roller, 112
... spur, 113 ... ejection roller, 114 ... spur, 115,
116 ... Guide member, 117 ... Recovery device.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takahiko Kuroda             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Junichi Azumi             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Mitsuru Irinoda             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Kaihei Isshiki             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F-term (reference) 2C057 AF52 AF93 AG30 AG53 AG54                       AG70 AP14 AP32 AP34 AP56                       AP79 AQ02 BA05 BA15                 3H077 AA06 BB10 CC01 CC09 DD05                       DD11 EE15 EE26 EE34 EE36                       EE37 FF02 FF03 FF06 FF32

Claims (15)

[Claims] 1. A nozzle for discharging a droplet, a pressurized liquid chamber communicating with the nozzle, a movable plate forming a part of a wall surface of the pressurized liquid chamber, and a movable plate provided on a surface of the movable plate. A plurality of electrodes, which deforms the movable plate by an electrostatic force acting between the electrodes to discharge droplets from the nozzles, in the side where the electrodes of the movable plate are formed. A droplet discharge head characterized in that a supporting and protective substrate for protecting the electrodes is bonded to the surface. 2. A space is formed between the support / protective substrate and the electrode on the movable plate surface.
The droplet discharge head according to 1. 3. The droplet discharge head according to claim 1, wherein the space has a step formed on the side of the support / protection substrate. 4. The droplet discharge head according to claim 1, wherein the space is formed by forming a step on the substrate on the side where the electrode is formed. 5. The droplet discharge head according to claim 1, wherein the joint portion of the support / protection substrate is formed in an electrode lead portion. 6. The droplet discharge head according to claim 5, wherein the support / protection substrate is an insulating substrate. 7. The droplet discharge head according to claim 5, wherein an insulating layer is formed on the surface of the electrode lead portion and / or the support / protection substrate. 8. The liquid droplet ejection head according to claim 1, wherein the space is formed by a patterned spacer formed between the support / protective substrate and an electrode surface. 9. The liquid droplet ejection head according to claim 1, wherein the joint between the support / protective substrate and the movable plate surface is formed so as to surround the outer periphery of the chip. 10. The droplet discharge head according to claim 1, wherein the joint portion of the support / protection substrate is formed so as to surround the movable plate array. 11. The bonding portion of the support / protection substrate is formed so as to surround the bit.
9. The droplet discharge head according to any one of 8 to 8. 12. An ink cartridge in which an ink jet head for ejecting ink droplets and an ink tank for supplying ink to the ink jet head are integrated,
An ink cartridge, wherein the inkjet head is the inkjet head according to any one of claims 1 to 13. 13. An ink jet recording apparatus equipped with an ink jet head for ejecting ink droplets, wherein the ink jet head is the liquid droplet ejecting head according to any one of claims 1 to 13. . 14. A micropump for transporting a liquid by deformation of a movable plate, wherein at least two electrodes are provided on at least one surface of the movable plate, and the movable plate is deformed by an electrostatic force acting between these electrodes. A micro pump characterized by that. 15. A light modulation device that changes the reflection direction of light by deforming a mirror, wherein the mirror is deformed by deforming a movable plate, and at least two electrodes are provided on at least one surface of the movable plate, An optical modulation device characterized in that the movable plate is deformed by an electrostatic force acting between electrodes.