JP2002205409A - Ink-jet head and ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet head which generates little irregularity in the ink droplet ejecting characteristic, and an ink-jet recording apparatus which improves image quality. SOLUTION: An engraved part 12 to provide a gap 16 is formed in a vibration plate 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art An ink jet head used in an image recording apparatus such as a printer, a facsimile, a copying apparatus, a plotter or the like which is used as an image forming apparatus includes a nozzle for discharging ink droplets and a discharge chamber communicating with the nozzle. (Pressurized liquid chamber, pressure chamber, liquid chamber,
Also referred to as an ink flow path. ), A diaphragm forming a wall surface in the discharge chamber, and an electrode facing the diaphragm,
There is an electrostatic inkjet head that presses ink in a discharge chamber by deforming and displacing a diaphragm by electrostatic force to discharge ink droplets from nozzles.

[0003] As such an electrostatic ink jet head, conventionally, as described in Japanese Patent Application Laid-Open No. 6-71882, a diaphragm forming a wall surface of a discharge chamber and electrodes are arranged in parallel ( The gap formed by this is called a “parallel gap”.

Further, as described in Japanese Patent Application Laid-Open No. 9-39235, a gap is provided between a diaphragm and an electrode, and the gap is gradually changed by arranging the electrode in a stepwise manner. Or JP-A-9
As described in JP-A-193375, by disposing an electrode obliquely and obliquely so as to face the diaphragm, the cross-sectional shape of the gap between the diaphragm and the electrode is changed to the surface (side) on the diaphragm side. There is also known one in which at least a part thereof is non-parallel to a surface (side) on the electrode side (such a gap is referred to as a “non-parallel gap”).

In such an electrostatic ink-jet head, a gap formed between the diaphragm and the electrode must be formed with high precision. Using a silicon substrate formed with an oxide film on a silicon substrate or an insulating substrate such as Pyrex (registered trademark) glass, a groove for forming an electrode having a predetermined depth is carved in the oxide film or the insulating substrate, and a predetermined thickness is formed on the bottom of the groove. By forming an electrode other than the oxide film or the groove of the insulating substrate as a gap spacer portion that defines a gap between the diaphragm and the electrode, a predetermined gap is formed between the diaphragm and the electrode. The gap length is obtained.

[0006]

However, in the above-mentioned conventional electrostatic ink-jet head, even when a parallel gap is formed between the diaphragm and the electrode, the depth of the groove (recess) for forming the electrode is reduced. (The height of the gap spacer part), the thickness of the electrode, and the thickness of the protective insulating film when the protective insulating film is formed on the surface of the electrode, the gap length ( The distance between the diaphragm surface and the electrode surface) varies, and the miniaturization of the gap is limited.

When a non-parallel gap is formed between the diaphragm and the electrode, particularly when a non-parallel gap starting from a gap length of zero is to be formed, a carved portion having a non-parallel gap shape is formed on the electrode substrate. Since an electrode must be formed in the engraved portion, the end of the electrode or the end of the protective insulating film formed on the surface of the electrode protrudes from the upper surface of the electrode substrate (the upper surface of the gap spacer portion) or becomes lower than the upper surface of the electrode substrate. As a result, steps and irregularities occur on the electrode substrate surface.

For this reason, it becomes difficult to bond such an electrode substrate and a substrate provided with a diaphragm (referred to as a diaphragm substrate or a flow path substrate), or to join the electrode substrate and the diaphragm substrate. As a result, the polishing allowance for enabling the polishing is increased, and the variation in the gap length is increased. When the gap length varies as described above, the ejection characteristics such as the ink droplet ejection volume and the ink droplet speed vary, and the ink landing position varies, thereby deteriorating the image quality.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide an ink jet head having less variation in ink droplet ejection characteristics and an ink jet recording apparatus having improved image quality.

[0010]

In order to solve the above-mentioned problems, an ink-jet head according to the present invention has a structure in which a sculpture portion serving as a gap is formed on a diaphragm.

The ink jet head according to the present invention has a structure in which a carved portion serving as a gap is formed in the diaphragm, and the electrodes are at least wider than the carved portion and are flat within the range.

In each of these ink jet heads according to the present invention, it is preferable that a carved portion serving as a gap is formed by thermal oxidation and removal of the portion by using a silicon substrate as a substrate for forming a diaphragm.

An ink jet head according to the present invention has a structure in which a carved portion serving as a gap is formed in an insulating film formed on the surface of a diaphragm.

The ink jet head according to the present invention has a structure in which a carved portion serving as a gap is formed in the insulating film formed on the surface of the diaphragm, and the electrodes are at least wider than the carved portion and are flat within the range. Things.

In each of these ink jet heads according to the present invention, a silicon substrate is used as a substrate for forming a vibration plate, and the silicon substrate has a vibration comprising a high-concentration boron diffusion layer only in an area where a carved portion or a gap is formed. Preferably, a plate is formed.

Further, in the ink jet head according to the present invention in which the engraved portion serving as a gap is formed on the diaphragm, a silicon substrate is used as a substrate on which the diaphragm is formed, and the diaphragm is formed only in a portion where the gap is formed on the silicon substrate. It is preferable that a high-concentration boron diffusion layer is formed, and the engraved portion serving as a gap is formed by accelerated oxidation of the boron diffusion layer and removal of the oxide film.

Further, in the ink jet head according to the present invention in which the diaphragm is formed of a high-concentration boron layer, it is preferable that the discharge chamber is located in a region where the high-concentration boron diffusion layer is formed.

It is preferable that the gap formed by the engraved portion has an inclined surface having a cross-sectional shape and a gap length of zero. Further, the opening of the gap is preferably sealed. Here, it is preferable to provide a means for releasing the gap internal pressure to the atmospheric pressure during the production.

An ink jet recording apparatus according to the present invention comprises:
It is equipped with an inkjet head according to the present invention.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a first embodiment of an ink jet head to which the present invention is applied is shown in FIGS.
This will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view of the head in the transverse direction of the diaphragm, and FIG. 2 is a schematic cross-sectional view of the head in the longitudinal direction of the diaphragm.

This ink jet head has a flow path substrate 1 as a first substrate, an electrode substrate 3 as a second substrate provided below the flow path substrate 1, and a third substrate provided above the flow path substrate 1. It has a structure in which a nozzle plate 4 serving as a substrate is laminated, and has a plurality of nozzles 5 for discharging ink droplets, a discharge chamber 6 which is an ink flow path communicating with each nozzle 5, and each discharge chamber 6 also serves as an ink supply path. A common liquid chamber 8 and the like communicating with each other via the fluid resistance portion 7 are formed.

The flow path substrate 1 has a plurality of discharge chambers 6 with which the nozzles 5 communicate with each other, and a concave portion forming a diaphragm 10 (also serving as a common electrode) serving as a bottom surface which is a wall surface of the discharge chamber 6, and a fluid resistance portion. 7 and a recess forming the common liquid chamber 8 are formed.

On the surface of the flow path substrate 1 in the out-of-plane direction (on the side of the electrode substrate 3) of the vibration plate 10, a carved portion 12 serving as a gap having a predetermined sectional shape is formed. A portion of the flow path substrate 1 without the engraved portion 12 forms a gap spacer portion 13 for precisely maintaining a gap 16 with an electrode 15 as an individual electrode described later.

For the flow path substrate 1, an SOI substrate in which an active layer substrate 23 is bonded to a base substrate 21 made of a silicon substrate via an oxide film 22 is used, and the concave portion serving as the discharge chamber 6 is etched with a KOH aqueous solution or the like. By performing anisotropic etching using the liquid, the vibration plate 10 including the active layer substrate 22 can be formed with the oxide film 22 serving as an etch stop layer.

As the electrode substrate 3, a silicon substrate is used.
An oxide film 3 is formed on the surface of the silicon substrate by a thermal oxidation method or the like.
a, an electrode (individual electrode) 15 is formed on the oxide film 3a through a gap 16 formed by the engraved portion 12 in the vibration plate 10, and a protective insulating film 17 is formed on the electrode 15. The electrode 15 and the protective insulating film 17 are separated into each channel by a separation groove 18. An electrostatic microactuator is constituted by the diaphragm 10 and the electrode 15 facing each other via the gap 16. The electrode 15 extends to near the end of the electrode substrate 3 to form an electrode pad portion 15a for connection to an external drive circuit via a connection means.

Here, the electrode 15 is a polysilicon film,
The protective insulating film 17 is formed of an HTO film (high-temperature oxide film: High-Temper).
and formed flat at least in a region wider (larger) than the engraved portion 12 forming the gap 16. By forming the electrode 15 and the protective insulating film 17 flat in a region wider than the engraved portion 12 as described above, a highly accurate gap 16 can be obtained.

It should be noted that, as the electrode 15, a tungsten silicide film, a titanium silicide film, or a laminated film thereof may be used instead of the polysilicon film. As the protective insulating film 17, a polysilicon oxide film obtained by thermally oxidizing polysilicon or an HTO film formed by high-temperature thermal CVD is preferably used.

As the protective insulating film 17, for example, an LP-CVD nitride film, a plasma oxide film, a plasma nitride film, a sputter-based insulating film, or a laminated film thereof may be used. The film has many levels of electron traps in the film, and the electrical deterioration is accelerated. In this case, the film thickness can be increased in order to alleviate electrical deterioration, but the drive voltage must be increased because the gap length (the distance between the diaphragm 10 and the electrode 15) increases.

Here, the gap 16 formed by the engraved portion 12 between the electrode 15 and the diaphragm 10 is the gap 1
At the end of No. 6, there is a portion where the gap length becomes “0” (zero) (an inclined surface having a gap length of zero in cross-sectional shape). The Gaussian shape is preferable as the cross-sectional shape of the gap 16 in order to facilitate low-voltage driving. However, even if the shape is other than this, the effect of lowering the voltage can be obtained to some extent by having an appropriate inclination. However, the present invention is not limited to this.

Although the gap 16 formed by the engraved portion 12 is notably shown in the figure, the actual dimensions are, for example, a thickness of the diaphragm 10 of 2 μm, a width of the diaphragm 10 of 125 μm, 10, length 800 μm, depth of the engraved part 12 0.2 μm, thickness of the electrode 15 0.3
μm, the thickness of the protective insulating film 17 of the electrode 15 is 0.2 μm, and the width of the gap spacer portion 13 (the width of the region directly joined).
It will be 44 μm.

The flow path substrate 1 (more specifically, the gap spacer portion 13) and the electrode substrate 3 (more specifically, the protective insulating film 17) are directly bonded to silicon (DB: silicon).
conDirect-Bonding) method.

The nozzle plate 4 has a large number of nozzles 5 formed by using a metal layer or a laminated member in which a metal layer and a polymer layer are joined, a resin member, nickel electroforming, or the like. In order to ensure water repellency with the ink, a water repellent film is formed on the surface in the direction (ejection surface) by a known method such as a plating film or a water repellent coating. The nozzle plate 4 has an ink supply port 19 for supplying ink to the common liquid chamber 8 from outside.

In the ink-jet head thus configured, the diaphragm 10 is used as a common electrode, the electrode 15 is used as an individual electrode, and a driving voltage is applied between the diaphragm 10 and the electrode 15 so that the diaphragm 10 The vibrating plate 10 is deformed and displaced toward the electrode 15 by an electrostatic force generated between the vibrating plate 10 and the electrode 15, and in this state, the electric charge between the vibrating plate 10 and the electrode 15 is discharged (driving voltage is set to zero) to vibrate. When the plate 10 undergoes a return deformation and the internal volume (volume) / pressure of the ejection chamber 6 changes, ink droplets are ejected from the nozzles 5.

That is, when a pulse voltage is applied to the electrode 15 serving as an individual electrode, a potential difference is generated between the electrode 15 and the diaphragm 10, and an electrostatic force is generated between the electrode 15 and the diaphragm 10. As a result, the diaphragm 10 is displaced according to the magnitude of the applied voltage. After that, the applied pulse voltage falls, whereby the displacement of the diaphragm 10 is restored, and the restoring force increases the pressure in the ejection chamber 6, thereby ejecting ink droplets from the nozzles 5.

In this case, since the electrostatic force acting on the diaphragm 10 becomes larger as the gap length between the diaphragm 10 and the electrode 15 becomes shorter, the deformation of the diaphragm 10 starts from the portion where the gap length is zero, Since the gap length becomes shorter in accordance with the deformation, the diaphragm 10 can be deformed and displaced at a low voltage, and low voltage driving can be achieved.

In the ink jet head, the engraved portion 12 serving as the gap 16 is formed on the diaphragm 10.
, A highly accurate non-parallel gap can be easily formed. Then, the diaphragm 10 and the electrode 15
Is formed by the engraved portion 12 formed on the diaphragm 10 itself, and the electrode 15 and the protective insulating film 17 are at least wider (larger) than the engraved portion 12.
Since it is formed flat in the region, a highly accurate non-parallel gap can be easily formed.

Here, it has been found that the non-parallel gap is extremely advantageous for lowering the voltage as compared with the parallel gap. In this case, although depending on the inclination angle, when the inclination is gentle, the diaphragm 10 smoothly abuts on the electrode 15 from the gap side where the gap length is zero (electrode 1).
5), and not only the effect of lowering the voltage, but also the pressure fluctuation in the discharge chamber 6 and the meniscus vibration near the nozzle 5 can be reduced.

Therefore, the gap 16 formed by the engraved portion 12 is formed to have a cross-sectional shape having an inclined surface having a gap length of zero, so that variations in the amount of ink droplets ejected and the ink ejection speed are small, and controllability is low. In addition, the accuracy of the ink droplet landing position on the paper surface is improved, and high-quality printing can be performed.

In this embodiment, the gap 16 has a Gaussian distribution shape (the shape is triangular for simplicity). This Gaussian shape is
It has been confirmed through simulations and experiments that it is most effective in lowering the voltage, although it is inferior in terms of smooth contact as compared with a gentle inclination.

In this ink jet head, since the opening (periphery) of the gap 16 is sealed by the gap spacer portion 13, it is possible to prevent foreign matters such as water and dust from entering the gap 16.

Next, an ink jet head according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a schematic cross-sectional explanatory view of the head in the lateral direction of the diaphragm, and FIG. 4 is a schematic cross-sectional explanatory view of the head in the longitudinal direction of the diaphragm.

This ink jet head is provided with a flow path substrate 1
A high-concentration P-type impurity layer (here, a high-concentration boron diffusion layer) 30 is formed on the silicon substrate, and a diaphragm 10 including the high-concentration boron diffusion layer 30 is formed. Then, the engraved portion 1 serving as a gap 16 is formed in an out-of-plane direction (the electrode substrate 2 side) of the diaphragm 10.
2 are formed. The discharge chamber 6 is formed in the region where the high-concentration boron diffusion layer 30 is formed.

Here, the diaphragm 10 made of the high-concentration boron diffusion layer 30 is formed only in the area where the engraved portion 12 or the gap 16 is formed. Thereby, as described later, the formation of the gap 16 and the formation of the boron diffusion layer 30 for the diaphragm can be performed with one mask, and the manufacturing cost can be reduced.

Further, the diaphragm 10 is made of the high-concentration boron diffusion layer 3.
By setting the thickness to 0, the thickness control of the diaphragm becomes easier as compared with the case where the diaphragm is formed using the active layer substrate of the SOI substrate described in the first embodiment. That is, several μ
Although an SOI substrate having an active layer substrate 23 of m or less is already on the market, it is still strict at this stage to satisfy the specifications required for the electrostatic ink jet head. For example, in the case of the active layer substrate 23 having a thickness of 2 μm, the specification value due to the variation is about ± 0.5 μm or less. On the other hand, when a high-concentration boron diffusion layer is formed on a silicon substrate and this is used as an etching stop layer to stop etching (hereinafter referred to as boron stop) to form the diaphragm 10 including the high-concentration boron diffusion layer. For example, about 2 μm ± 0.1 to 0.2 μm, or
It is possible to control the thickness less than that.

Next, a manufacturing process of the ink jet head according to the second embodiment will be described with reference to FIGS. First, as shown in FIG.
On a silicon substrate 31 (using a silicon wafer) serving as a flow path substrate 1 that forms a base of the discharge chamber 6 and the discharge chamber 6.
An oxide film mask pattern 33 is formed corresponding to the region where the engraved portion 12 is to be formed. Then, as shown in FIG. 1B, a high-concentration boron diffusion layer 30 for forming the diaphragm 10 is formed by a known solid diffusion method or coating diffusion method. At this time, a boron glass layer 34 is formed on the entire surface of the silicon substrate 31.

Then, as shown in FIG. 3C, after the boron glass 34 and the oxide film mask pattern 33 are removed by buffered hydrofluoric acid, a desired surface of the silicon substrate 31 on the high concentration boron diffusion layer 30 side is formed. Using a mask (a type of photomask) in which a gradation pattern corresponding to the engraving depth is formed, a resist pattern 36 in which a concave portion 35 corresponding to the engraved portion 12 having a desired engraving depth and cross-sectional shape is formed.

Then, as shown in FIG. 4D, the engraved portion 12 is formed in the high-concentration boron diffusion layer 30 by transferring the resist pattern 36 to the surface of the silicon substrate 31 by using a dry etching technique. In this case, the etching rate of the resist pattern 36 is
1 (more specifically, the high-concentration boron diffusion layer 30) is usually set to be higher than the etching rate. However, since the transfer is not performed simply in proportion to the etching rate ratio, the resist shape corresponding to the desired shape is not always obtained. The etching conditions are matched.

Thereafter, as shown in FIG. 4E, the remaining resist pattern 36 is removed to remove the silicon substrate 31 having the engraved portion 12 formed in the high-concentration boron diffusion layer 30 forming the diaphragm 10. Is obtained.

On the other hand, as shown in FIG. 6A, an oxide film 3a having a thickness of, for example, about 0.5 to 2.0 μm is formed on the electrode substrate 3 made of a silicon substrate by a thermal oxidation method or the like. The type of the oxide film is not limited to this. The thickness is preferably relatively large in order to reduce the capacitive coupling between the electrodes 15 via the electrode substrate 3. The resistance is appropriately set by the resistance, the capacitance of the driver for driving the resistor, and the voltage, and is not limited thereto.

Then, as shown in FIG. 3B, a polysilicon film 37 for forming the electrode 15 is formed on the oxide film 3a of the electrode substrate 3. Here, phosphorus was ion-implanted and thermally diffused to reduce the resistance of the polysilicon film 37.

The introduction of the impurity for lowering the resistance into the polysilicon film 37 is not limited to this, and any other known technique may be used. The roughness can be minimized. It has also been confirmed that doped polysilicon, which introduces impurities during film formation, has relatively good surface properties, but the surface properties decrease when the film thickness is increased in accordance with the reduction in resistance. In addition, it has been confirmed that the crystal growth of polysilicon is remarkable and the surface roughness is increased by the method using deposition diffusion using a diffusion source. Other than the polysilicon film 37, tungsten silicide, titanium silicide, a laminated film of these, or the like can be used as an electrode material.

Subsequently, on the surface of the polysilicon film 37, an HTO film (high-temperature oxide film) 38 formed by high-temperature thermal CVD to be a protective insulating film 17 is formed in order to insulate the vibration plate 10 and the electrode 15 from each other. Film. Note that the protective insulating film 17 may be, for example, a polysilicon oxide film obtained by thermally oxidizing the polysilicon film 37.

Then, the surface of the HTO film 38 is mirror-polished. This polishing step is for improving the morphology of the surface and easily directly joining the electrode substrate 3 and the silicon substrate 31 to be the flow path substrate 1. Since this polishing step is intended to improve the morphology of the surface, the polishing amount is preferably as small as possible. However, it is necessary to polish the micro-roughness of the polished surface until the surface morphology becomes about 1 nm or less. A desired polished surface can be obtained with a polishing amount of about 0.005 to 0.2 μm.

It should be noted that the polishing amount is the polysilicon film 37 and / or
Alternatively, the polishing amount is appropriately determined based on the surface morphology of the HTO film 38, and is not limited to the range of the polishing amount. Since the morphology of the polysilicon film 37 varies depending on the polysilicon forming method (such as a film forming method, an impurity introducing method for lowering resistance, an impurity activating method, etc.) and a film thickness, it is necessary to appropriately set the polishing amount accordingly. However, this does not mean that the polishing amount varies within the range of the polishing amount. If such a polishing step is not performed, the bonding strength at the time of direct bonding becomes extremely weak, and the number of voids generated on the bonding surface increases,
Sometimes they are not joined at all.

Further, S used for manufacturing a semiconductor LSI or the like can be used.
The formation of the OI substrate usually requires a morphology of about 0.3 nm or less, but in the case of the present invention, the electrode substrate 2 does not peel off from the silicon substrate 31 serving as the flow path substrate 1 in a later step. It is sufficient that a bonding strength of a certain level can be obtained, and experiments have confirmed that such bonding is possible if the surface morphology does not exceed 1 nm.

Next, as shown in FIG. 3C, the isolation trenches 18 are formed in the polysilicon film 37 and the HTO film 38 by using a known photolithography technique and etching technique, so that the polysilicon of each channel is formed. Electrode 1 made of silicon film 37
5 and a protective insulating film 17 composed of an HTO film 38. At this time, the pattern of the laminated film of the electrode 15 and the protective insulating film 17 is the same as that of the silicon substrate 3 serving as the flow path substrate 1 described above.
1, the surface of the uppermost protective insulating film 17 is flattened by the above-described surface polishing treatment.

Next, as shown in FIG. 7A, the silicon substrate 31 serving as the flow path substrate 1 and the electrode substrate 3 are directly bonded. At this time, as described above, the high-concentration boron diffusion layer 30 is formed only on the engraved portion 12 (the portion where the gap 16 is formed) on the silicon substrate 31, and the high-concentration boron diffusion layer 30 is formed on the portion to be the gap spacer portion 13. Is not formed, the direct bonding with the electrode substrate 3 can be performed without going through the polishing step of the silicon substrate 31.

That is, when the high-concentration boron diffusion layer 30 is formed, the micro-roughness of the surface is usually large. Therefore, when bonding the boron diffusion surface to another silicon substrate, the surface of the silicon substrate is polished. It is necessary to reduce the micro roughness. On the other hand, the silicon substrate 31 avoids the gap spacer portion 13 which is bonded to the electrode substrate 3 so as to avoid the high-concentration boron diffusion layer 30.
Is formed, the bonding surface (gap spacer portion 13) is formed.
No micro-roughness occurs on the surface of the silicon substrate 31 and the electrode substrate 3 (which is a silicon substrate) can be directly bonded without polishing the surface of the silicon substrate 31.

Next, as shown in FIG. 6B, a concave portion 38 for a flow pattern such as the discharge chamber 6 is carved in the silicon substrate 31, and a diaphragm composed of the discharge chamber 6 and the high-concentration boron diffusion layer 30 is formed. 10 and the like are formed to obtain the flow path substrate 1. Here, a silicon substrate having a crystal plane orientation (110) is used as the flow channel substrate 1 and KOH of about 10 to 30 wt% is used.
Anisotropic etching was performed using an aqueous solution, and a mask for the anisotropic etching was used by patterning a nitride film or a stacked film of an oxide film and a nitride film by low-pressure CVD or plasma CVD.

Thereafter, as shown in FIG. 1C, the nozzle plate 4 having the nozzles 5 formed thereon is joined to the flow path substrate 1 to complete a desired ink jet head.

Here, the fact that the non-parallel gap can be easily formed in the ink jet heads according to the first and second embodiments will be described with reference to FIGS. 8 and 9 showing a comparative example. As described above, in each embodiment, the engraved portion 1 in which the gap 16 is engraved on the diaphragm 10.
2, and the electrode 15 (more specifically, the surface of the protective insulating film 17) is flat in a wider range than the engraved portion 12, that is, the engraved portion 12 (or the gap 1).
Since the area of the protective insulating film 17 and the area of the electrode 15 are formed larger than the area of 6), the gap shape and the engraving depth can be manufactured uniformly with good controllability, and the gap can be smoothly contacted. Zero non-parallel shapes can be easily formed.

On the other hand, when a concave portion is formed in the electrode substrate 3 and the electrode 15 is formed in this concave portion, that is, the bonding portion of the electrode substrate 3 and the electrode 15 (or the laminated film including the protective insulating film 17) are formed. If the layers are in different layers, a considerable amount of positive / negative step occurs, and a desired gap length cannot be obtained, or in some cases, direct bonding cannot be performed.

That is, as shown in FIG. 8A, for example, a concave portion 41 which is a groove for forming an electrode is formed in the oxide film 3a of the electrode substrate 3, and the electrode 15 and the protective insulating film 17 are formed on the bottom surface of the concave portion 41. When the protective insulating film 1 is formed by laminating
7 is lower than the bonding surface of the bonding portion 43 of the electrode substrate 3, the silicon substrate 31 serving as the flow path substrate 1 can be bonded as shown in FIG.
(The distance between the electrode and the diaphragm) is affected by the variation in the depth of the concave portion 41, the variation in the thickness of the electrode 15, and the variation in the thickness of the protective insulating film 17, and the gap length varies.

As shown in FIG. 9A, for example, a concave portion 41 serving as a groove for forming an electrode is formed in an oxide film 3a of an electrode substrate 3.
When the electrode 15 and the protective insulating film 17 are laminated on the bottom surface of the concave portion 41 and the surface of the protective insulating film 17 is higher than the bonding surface of the bonding portion 43 of the electrode substrate 3,
As shown in FIG. 2B, it becomes impossible to join the silicon substrate 31 serving as the flow path substrate 1 to the electrode substrate 3.

Therefore, when forming the engraved portion 12 serving as the gap 16 on the diaphragm 10, the electrode 15 extends over a wider area than the engraved portion 12, that is, the junction between the electrode substrate 3 and the flow path substrate 1 (gap spacer portion). It is preferable that the region including 13) be a flat surface.

Next, an ink jet head according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 10 is a schematic cross-sectional view of the head in the transverse direction of the diaphragm, and FIG. 11 is a schematic cross-sectional view of the head in the longitudinal direction of the diaphragm. In this ink jet head, an electrode 15 made of a polysilicon film is formed on an oxide film 3a of an electrode substrate 3, and a protective insulating film 17 made of an HTO film is formed on the surface of each electrode 15 and in a separation groove 18 between each electrode 15. It was done.

In this case as well, the resistance was reduced by ion-implanting phosphorus and thermally diffusing phosphorus into the polysilicon film serving as the electrode 15, but the introduction of impurities for lowering the resistance is not limited to this. The electrode 15 is not only a polysilicon film, but also
A tungsten silicide film, a titanium silicide film, a stacked film thereof, or the like can also be used. The reason why the HTO film is used as the protective insulating film 47 is that the
This is because the O film is of a surface reaction type, which can reliably fill the separation groove 18 between the electrodes 15 and has high insulation quality, but the surface reaction type protection insulating film is not limited to this. Further, the pattern of the laminated film of the electrode 15 and the protective insulating film 47 is a flat surface in an area (large pattern) wider than the engraved portion 12 on the diaphragm 10.

As the flow path substrate 1, the first substrate described above is used.
A high-concentration boron diffusion layer is formed on the flow path substrate 1 in which the vibration plate 10 is formed of an active layer substrate using the SOI substrate of the embodiment, or on the silicon substrate of the second embodiment.
Any of the flow path substrates 1 on which is formed can be used. Therefore, in order to show that either of the embodiments may be used, detailed illustration of the flow path substrate 1 is omitted (the same applies to the following description of the embodiments).

In order to manufacture such an ink jet head, the oxide film 3a of the electrode substrate 3 made of a silicon substrate is required.
A polysilicon film as an electrode material is formed thereon, and a separation groove 18 having a width of, for example, 0.5 μm is formed in the polysilicon film by a known photoengraving technique and etching technique, and is separated into electrodes 15 for each channel. After that, an HTO film as a protective insulating film 17 is formed on the electrode 15 and the isolation groove 18 is filled with the HTO film. After that, the surface of the protective insulating film 17 is mirror-polished so that the surface can be directly bonded to the silicon substrate to be the flow path substrate 1. The steps after the direct bonding step with the silicon substrate serving as the flow path substrate 1 are the same as those described as the manufacturing steps of the ink jet head of the second embodiment.

According to the ink jet head configured as above, the same operation and effect as those of the first and second embodiments can be obtained, and the separation groove 18 between the electrodes 15 is completely buried with the protective insulating film 17. Therefore, the entire surface of the electrode substrate 3 becomes flat, and the periphery of the gap 16 can be completely sealed. This also allows for
In the case where the inside of the gap 16 is used at atmospheric pressure, even if the communication hole is formed, there is no flow of air or inflow of water from the electrode pad portion 15a, for example, no inflow of water during the dicing step. Without passing through the step of sealing the air, the air flow and the inflow of water can be prevented.

Next, an ink jet head according to a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 12 is a schematic cross-sectional explanatory view of the head in the longitudinal direction of the diaphragm, and FIG. 13 is a schematic cross-sectional explanatory view of the head in the transverse direction of the diaphragm. The ink jet head includes a surface of the flow path substrate 1 on the electrode side of the diaphragm 10 and the electrode substrate 3
Protective insulating film 4 on any of the surfaces of the electrodes 15 on the diaphragm side.
7 and 17 are formed.

In the case where the protective insulating films 47 and 17 are formed on both the surface of the diaphragm 10 and the electrode 15 as described above, the residual insulating films 47 and 17 remain as compared with the case where the protective insulating films 47 and 17 are formed on the surface of either the diaphragm 10 and the electrode 15. Experiments have confirmed that the charge is reduced.

That is, although the details of the mechanism of the electrostatic ink jet head are unknown, even when the applied voltage between the diaphragm 10 and the electrode 15 is turned off, apparently electric charges remain between the electrodes 15. The phenomenon of doing so has been confirmed. Various electrical measures are taken to avoid this effect.
It has been confirmed that this effect is small when the protective insulating films 48 and 17 are provided on both the zero surfaces.

Next, an ink jet head according to a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 14 is a schematic cross-sectional view of the head in the transverse direction of the diaphragm, and FIG. 15 is a schematic cross-sectional view of the head in the longitudinal direction of the diaphragm. In this ink jet head, an oxide film 48 also serving as a protective insulating film is formed on the electrode side surface of the vibration plate 10 of the flow path substrate 1, and the engraved portion 12 serving as the gap 16 is formed in the oxide film 48.

Although the protective insulating film 17 is not formed on the electrode 15 side here, as described in the fourth embodiment, it is more desirable to form the protective insulating film 17 on the electrode 15 side as well. It is effective for securing and avoiding residual charges.

The engraved portion 12 is formed on the insulating film (oxide film) 48 formed on the diaphragm 10 like the ink jet head.
The gap controllability (gap accuracy) of the non-parallel shape is improved as compared with the case where the engraved portion 12 is formed on the diaphragm 10 itself. That is, the engraving part 1
In the case where 2 is formed by etching, the gap accuracy of the engraved portion 12 is caused by the selectivity to the resist mask and the etching stability. However, when the oxide film 48 is processed, it is more controlled than when the silicon substrate is processed. The nature becomes high.

When the engraved portion 12 is formed in the insulating film 48 of the diaphragm 10, the insulating film 48 is formed as compared with the case where the engraved portion 12 is formed in the diaphragm 10 (in the first to fourth embodiments). Since the distance between the diaphragm 10 and the electrode 15 increases by the thickness of the gap, the effective electric field of the gap 16 is correspondingly lost, and the effect of lowering the voltage by using a non-parallel gap is slightly reduced. However, the insulating film 48
Since the dielectric constant (relative dielectric constant: 3.8) of the oxide film is about four times that of air (relative dielectric constant: 1), the effect of lowering the voltage is slightly reduced. Engraved part 1 that becomes gap 16
2 may be formed on the diaphragm 10 or the insulating film 48 depending on the purpose. However, if emphasis is placed on the process surface, it is better to form the engraved portion 12 on the insulating film 48. This is considered to be more advantageous than the case of forming

Next, an ink jet head according to a sixth embodiment of the present invention will be described with reference to FIGS. FIG. 16 is a schematic cross-sectional view of the head in the transverse direction of the diaphragm, and FIG. 17 is a schematic cross-sectional view of the head in the longitudinal direction of the diaphragm. In this ink-jet head, the engraved portion 12 serving as the gap 16 of the flow path substrate 1 is formed by thermal oxidation and removal of the portion. The engraved portion 12 here has a shape that forms a parallel gap.

As described above, by forming the engraved portion 12 for the gap by thermal oxidation and removing the portion, the gap accuracy and reproduction can be improved more than in the process of forming the engraved portion using a resist mask or photolithography. The performance is improved.

The manufacturing process of the ink jet head according to the sixth embodiment will be described with reference to FIGS. First, as shown in FIG. 18A, a buffer oxide film 54 for preventing surface roughness of a surface directly bonded to the silicon substrate 31 to be the flow path substrate 1 is formed. LP-C used as prevention mask
A low-pressure nitride film such as a VD nitride film, an LP-SiN film or the like is formed, and these are patterned using a known photolithography technique and an etching technique to form a mask pattern of the buffer oxide film 54 and the nitride film 55. .

Then, as shown in FIG. 9B, thermal oxidation for obtaining a desired gap 16 is performed using the nitride film 55 as an oxidation mask to form an oxide film 56. For example, in order to obtain the gap 16 having a gap length of 0.2 μm, the oxide film 56 having a thickness of about 0.44 μm may be formed.

Next, as shown in FIG.
6 is removed. Here, the oxide film 56 was removed with buffered hydrofluoric acid. Next, as shown in FIG. 4D, the nitride film 55 and the buffer oxide film 54 are sequentially removed. Here, the nitride film 55 was removed with hot phosphoric acid. As a result, the engraved portion 12 is formed on the silicon substrate 31 by thermal oxidation and removal of the portion.

Therefore, as shown in FIG. 19, the silicon substrate 31 is directly bonded to the electrode substrate 3 and discharged to the silicon substrate 31 in the same process as described in the manufacturing process of the ink jet head according to the second embodiment. After forming the recess such as the chamber 6 and the diaphragm 10, the nozzle plate 4 is joined to complete the ink jet head.

As described above, by forming the engraved portion 12 serving as a gap by thermal oxidation and its removal, the thickness control of the oxide film 56 is higher than the etching depth control. Higher gap accuracy and reproducibility can be obtained as compared with the formation of the engraved portion used.

Although the engraved portion having a parallel gap shape is formed here, a non-parallel shape gap can be formed by devising the mask pattern. However, as compared with the case where the photolithography technique using the gradation mask and the etching transfer technique are used, the degree of freedom is small and some restrictions are applied.

Next, an ink jet head according to a seventh embodiment of the present invention will be described with reference to FIGS. FIG. 20 is a schematic cross-sectional explanatory view of the head in the lateral direction of the diaphragm, and FIG. 21 is a schematic cross-sectional explanatory view of the head in the longitudinal direction of the diaphragm. This inkjet head has a high-concentration boron diffusion layer 3 for forming the diaphragm 10.
0 is formed only on the engraved portion 12 that becomes the gap 16,
Alternatively, the high-concentration boron diffusion layer 30 is formed only in the region where the engraved portion 12 for the gap is formed (which is a difference in the manufacturing process), and the same heat as in the sixth embodiment is used. The engraved portion 12 is formed by performing oxidation and removal of the portion.

As described above, the diaphragm 10 is used for forming
More specifically, the high-concentration boron diffusion layer 30 used for the boron stop is formed only in the engraved portion 12 serving as the gap 16 or only in the region where the engraved portion 12 for the gap is formed, so that direct bonding is performed later. As described above, the surface morphology of the gap spacer portion 13 to be formed does not decrease, a bonding surface having good surface properties can be secured, and the bonding reliability is improved.

Therefore, an example of the manufacturing process of the ink jet head according to the seventh embodiment will be described with reference to FIGS.
3 will be described. First, as shown in FIG. 22A, a buffer oxide film 54 for preventing surface roughness of a surface directly bonded to the silicon substrate 31 serving as the flow path substrate 1 is formed, and an oxide film is formed on the buffer oxide film 54. A low-pressure nitride film such as an LP-CVD nitride film or an LP-SiN film serving as a prevention mask is formed, and these are patterned using a known photolithography technique and etching technique to form a buffer oxide film 5.
4 and a mask pattern of the nitride film 55 are formed.

Then, as shown in FIG. 9B, thermal oxidation for obtaining a desired gap 16 is performed using the nitride film 55 as an oxidation mask to form an oxide film 56. For example, in order to obtain the gap 16 having a gap length of 0.2 μm, the oxide film 56 having a thickness of about 0.44 μm may be formed.

Next, after removing the oxide film 56 with buffered hydrofluoric acid or the like as shown in FIG.
As shown in FIG. 3, a high-concentration boron diffusion layer 3 for forming the diaphragm 10 by a known solid diffusion method or coating diffusion method.
0 is formed. At this time, a boron glass layer 34 is formed on the entire surface of the silicon substrate 31.

Therefore, as shown in FIG. 11E, the boron glass 34, the nitride film 55, and the buffer oxide film 54 are removed by buffered hydrofluoric acid, so that the high-concentration boron diffusion layer 30 forming the diaphragm 10 is formed. The silicon substrate 31 which becomes the flow path substrate 1 in which only the engraved portion 12 is formed is obtained.

Thereafter, as shown in FIG. 23, the silicon substrate 31 is replaced with the electrode substrate 3 in the same steps as those described in the manufacturing process of the ink jet head according to the second embodiment.
After forming the concave portion such as the discharge chamber 6 and the vibration plate 10 in the silicon substrate 31, the nozzle plate 4 is bonded to complete the ink jet head.

Next, another example of the manufacturing process of the ink jet head according to the seventh embodiment will be described with reference to FIG. First, as shown in FIG. 2A, a buffer oxide film 54 for preventing surface roughness of a surface directly bonded to the silicon substrate 31 serving as the flow path substrate 1 is formed, and an oxide film is formed on the buffer oxide film 54. Forming a low-pressure nitride film such as an LP-CVD nitride film, an LP-SiN film, etc., which serves as a prevention mask,
These are patterned using a known photoengraving technique and etching technique to form a buffer oxide film 54 and a nitride film 5.
5 are formed.

Next, as shown in FIG. 2B, using the buffer oxide film 54 and the nitride film 55 as a mask, high-concentration boron for forming the diaphragm 10 is formed by a known solid diffusion method or coating diffusion method. The diffusion layer 30 is formed. At this time,
A boron glass layer 34 is formed on the entire surface of the silicon substrate 31.

Then, after the boron glass 34 is removed by buffered hydrofluoric acid, thermal oxidation for obtaining a desired gap 51 is performed by using the nitride mask layer 55 as an oxidation mask as shown in FIG. Then, an oxide film 56 is formed. For example, in order to obtain a gap 51 having a gap length of 0.2 μm, an oxide film 56 having a thickness of about 0.44 μm may be formed. Next, as shown in FIG. 3D, the oxide film 56 is removed with buffered hydrofluoric acid.

Next, the nitride film 55 and the buffer oxide film 54 are sequentially removed as shown in FIG. Here, the nitride film 55 was removed with hot phosphoric acid. As a result, the high-concentration boron diffusion layer 30 is formed only in the region where the gap 16 is formed on the silicon substrate 31, and the engraved portion 12 is formed by thermal oxidation and removal of the portion.

Thereafter, as shown in FIG. 23, the silicon substrate 31 is directly bonded to the electrode substrate 3 in the same steps as those described in the manufacturing process of the ink jet head according to the second embodiment, and After forming the recess such as the discharge chamber 6 and the vibration plate 10, the nozzle plate 4 is joined to complete the ink jet head.

In any of the above manufacturing steps,
Gap formation and formation of high-concentration boron diffusion layer for diaphragm
This can be performed with one mask (nitride film 55), so that the manufacturing process can be simplified and the cost can be reduced.

Next, an ink jet head according to an eighth embodiment of the present invention will be described with reference to FIGS. FIG. 25 is a schematic cross-sectional view of the head in the transverse direction of the diaphragm, and FIG. 26 is a schematic cross-sectional view of the head in the longitudinal direction of the diaphragm. In this ink jet head, a high-concentration boron diffusion layer 30 for forming the vibration plate 10 is formed on a silicon substrate serving as the flow path substrate 1, and the high-concentration boron diffusion layer 30 is subjected to accelerated oxidation when thermally oxidized. Then, an oxide film in the high-concentration boron diffusion layer region is formed in a self-selective and thick manner, and then the oxide film is removed to form the engraved portion 12 which becomes the gap 16.

As described above, the engraved portion 12 is formed by the accelerated oxidation of the high-concentration boron diffusion layer and the removal of the oxide film, whereby the gap can be formed by a simple process at a low cost. Cost can be reduced.

The manufacturing process of the ink jet head according to the eighth embodiment will be described with reference to FIGS. First, as shown in FIG. 27A, the flow path substrate 1 forming the base of the diaphragm 10 and the discharge chamber 6 and the like.
Silicon substrate 31 (using a silicon wafer)
On top, a mask pattern 33 of an oxide film is formed corresponding to the region where the engraved portion 12 is to be formed. Then, FIG.
As shown in (1), a high-concentration boron diffusion layer 30 for forming the diaphragm 10 is formed by a known solid diffusion method or coating diffusion method. At this time, a boron glass layer 34 is formed on the entire surface of the silicon substrate 31.

Then, after removing the boron glass 34 and the oxide film mask pattern 33 with buffered hydrofluoric acid as shown in FIG. 3C, the silicon substrate 31 is thermally oxidized as shown in FIG. Perform processing. At this time, the oxide film 56 in a region corresponding to the boron diffusion layer 30 is formed to be thicker in a self-selective manner by utilizing the accelerated oxidation phenomenon of the boron diffusion layer 30.

Then, as shown in FIG. 11E, the oxide film 56 is removed with buffered hydrofluoric acid or the like. This allows
The engraved portion 12 that becomes the desired gap 16 is formed on the silicon substrate 31.

Thereafter, as shown in FIG. 28, the silicon substrate 31 is replaced with the electrode substrate 3 in the same steps as those described in the manufacturing process of the ink jet head according to the second embodiment.
After forming the concave portion such as the discharge chamber 6 and the vibration plate 10 in the silicon substrate 31, the nozzle plate 4 is bonded to complete the ink jet head.

Here, the relationship between the formation region of the high-concentration boron diffusion layer 30 forming the engraved portion for the gap and the formation region of the discharge chamber 6 will be described with reference to FIGS. It will be described with reference to FIG. As previously mentioned,
The high-concentration boron diffusion layer 30 forming the diaphragm 10 is formed only in the range where the engraved portion 12 is formed or the range where the gap 16 is formed so that micro roughness is not generated on the joint surface (the surface of the gap spacer portion 13). In this case, the discharge chamber 6 is formed in a region where the high-concentration boron diffusion layer 30 is formed, as shown in FIG.

On the other hand, when the size of the discharge chamber 6 is larger than the region where the high-concentration boron diffusion layer 30 is formed,
Since the boron stop does not work, as shown in FIG.
Since the flow path substrate 1 and the diaphragm 10 are partially or wholly separated from each other, the fixed end of the diaphragm 10 is only a small joint, and the diaphragm strength is weakened.

Therefore, by forming the discharge chamber 6 in the region where the high-concentration boron diffusion layer 30 is formed, the strength of the device is improved and the yield is improved.

Next, the sealing effect of the gap opening by forming the engraved portion 12 serving as the gap 16 in the vibration plate 10 or the insulating film 47 of the vibration plate 10 will be described with reference to FIGS. In the ink jet head according to the present invention, as shown in FIG. 30, since the engraved portion 12 serving as the gap 16 is formed in the vibration plate 10 or the insulating film 47 of the vibration plate 10, the opening (periphery) of the gap 16 is formed. Is completely sealed.

Therefore, when separating each head chip from the silicon wafer (during dicing), even if a part 1a of the flow path substrate 1 corresponding to the electrode pad portion 15a is removed as shown in FIG. Since the process does not flow into the gap 16, the process is simplified, and the cost can be reduced. In addition, since the opening (periphery) of the gap 16 is sealed, it is not affected by the use environment such as humidity and temperature. In an environment with high humidity, polka dots or water molecules are crosslinked by condensation. The diaphragm 10 is the electrode substrate 3
The phenomenon of sticking to the side can be avoided.

On the other hand, as shown in FIG. 31, an electrode forming groove (recess) 64 is formed in the oxide film 63a of the electrode substrate 63, and an electrode 65 is formed on the bottom surface of the electrode forming groove 64. In the case of a head configuration in which a protective insulating film 67 is formed on the surface of the electrode 65 and a portion other than the electrode forming groove 64 is a gap spacer portion 68 that defines the gap 66, the gap 66 is opened through the opening 66a on the electrode pad portion 55a side. Is done. Further, as shown in FIG. 32, a head configuration in which a protrusion 63b is formed between the electrode forming groove 64 and the opening 66a is also conceivable.

In the head structure of FIG. 31 or 32, however, the gap 66 is opened through the opening 66a, and it is difficult to completely seal the opening 66a. When the head chip group is divided into individual chips by dicing, water flows into the gap 66 from the opening 66a.

In order to prevent this, as shown in FIGS. 31 and 32, after dicing (chip formation) while leaving a portion 1a corresponding to the electrode pad portion 15a of the flow path substrate 1,
A step of removing the portion 1a and opening the electrode pad portion 15a must be taken. Therefore, it is necessary to form an electrode lead-out opening for each chip, and the merit of the wafer process is reduced by half. Further, when the electrode lead-out opening is formed in the wafer state, only the opening 66a must be sealed before sealing without sealing the electrode lead-out opening before dicing. Such sealing is considerably difficult in view of the heat history and the like in the post-process.

Therefore, the gap 16 can be easily formed by forming the engraved portion 12 on the diaphragm side (the diaphragm 10 itself or the protective insulating film 47 on the surface thereof) and forming the gap 16 like the ink jet head according to the present invention. 16 can be completely sealed, and the inconvenience caused by the opening of the gap 16 can be avoided.

Next, an ink jet head according to a ninth embodiment of the present invention will be described with reference to FIGS. FIG. 33 is an explanatory top view of the head with the nozzle plate omitted, and FIG. 34 is a schematic cross-sectional explanatory view in the longitudinal direction of the diaphragm along the line AA in FIG.

In this ink jet head, a communication path 71 communicating with each gap 16 is formed in the protective insulating film 17 of the electrode substrate 3 and a common communication path 72 communicating with each communication path 71 is provided. An air opening port 73 for opening an end of the common communication path 72 to the atmosphere is formed. The communication path 71, the common communication path 72, and the atmosphere opening port 73
This constitutes means for releasing the internal pressure of the gap to the atmospheric pressure during the production.

The communication passage 71, the common communication passage 72, and the air opening 73 are formed so as to avoid the electrode lead-out opening (electrode take-out part) and the dicing line. This prevents water or the like from flowing in during dicing. Further, the atmosphere opening port 73 performs the same processing as that of the diaphragm 10, that is, the flow path substrate 1 is made to have the same thickness as the diaphragm 10 at the portion of the atmosphere opening port 73, and at a necessary time, It can be abutted or penetrated by a laser beam or the like.

With such a configuration, the pressure in the gap can be easily released to the atmospheric pressure during the production, so that a reduction in injection efficiency and a variation in injection characteristics can be reduced. That is, the pressure in the sealed gap 16 is usually either positive pressure or negative pressure. For example, when the above-described direct bonding between the electrode substrate 3 and the flow path substrate 1 (silicon substrate 31) is performed under reduced pressure, the inside of the gap 16 is maintained at a certain reduced pressure. In this case, if the diaphragm 10 is extremely deformed before the voltage is applied between the diaphragm 10 and the electrode 15, not only the ejection efficiency is lowered, but also the driving voltage variation, the amount of ejected ink and the amount of ejected ink are reduced. Since various variations such as a variation in the speed and a variation in the ink droplet landing position occur, it is preferable to open the gap 16 to the atmospheric pressure in the atmosphere, nitrogen, or a rare gas. Therefore, in this inkjet head, a communication path 71 for opening the inside of the gap 16 to the atmosphere, a common communication path 72, and an atmosphere opening port 73 are provided.

If there is a gap in the separation groove 18 between the electrodes 15, water can flow from the gap through the common communication path 72 at the time of dicing or other cleaning. For complete prevention,
As in the ink jet head of the third embodiment, it is preferable that the electrode separation groove 18 is completely buried flat with no gap with the protective insulating film 17.

Next, the outline of the mechanism of the ink jet recording apparatus according to the present invention equipped with the ink jet head according to the present invention will be briefly described with reference to FIGS. 35 and 36. FIG. 35 is a perspective view for explaining an example of the ink jet printing apparatus according to the present invention, and FIG. 36 is an explanatory view of a mechanism of the printing apparatus. This ink jet head recording apparatus includes a carriage movable in the main scanning direction inside a recording apparatus main body 81, a recording head including an inkjet head mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. The mechanism unit 82 and the like are housed, the paper 83 fed from the paper feed cassette 84 or the manual feed tray 85 is taken in, a required image is recorded by the printing mechanism unit 82, and then the paper is fed to the paper output tray 86 mounted on the rear side. Discharge paper.

The printing mechanism 82 moves the carriage 93 in the main scanning direction (see FIG. 3) with a main guide rod 91 and a sub guide rod 92, which are guide members that are horizontally mounted on left and right side plates (not shown).
9 (in the direction perpendicular to the paper surface), and the carriage 93 ejects ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) according to the present invention. Head 94 composed of an inkjet head
Are mounted with the ink droplet ejection direction facing downward, and on the upper side of the carriage 93, ink tanks (ink cartridges) 95 for supplying ink of each color to the head 94 are exchangeably mounted.

Ink is supplied from the ink cartridge 95 into the head 94 through the ink supply port 19. Here, the ink supply port 19 is provided on the ink ejection surface (the nozzle plate 4 mounting surface) side in the examples up to the above embodiment, but is provided on the opposite side (rear surface side, base substrate side) or side surface side. Is not limited to this.

The carriage 93 is slidably fitted on the main guide rod 91 on the rear side (downstream side in the paper transport direction), and is mounted on the front guide rod 9 on the front side (upstream side in the paper transport direction).
2 slidably mounted. The carriage 93 is moved and scanned in the main scanning direction.
A timing belt 100 is stretched between a driving pulley 98 and a driven pulley 99 which are driven to rotate by the driving unit 7, and the timing belt 100 is fixed to a carriage 93.

Although the heads 94 of each color are used here as recording heads, a single head having the nozzles 5 for ejecting ink droplets of each color may be used.

On the other hand, in order to transport the paper 83 set in the paper feed cassette 84 to the lower side of the head 94, a paper feed roller 101 which separates and feeds the paper 83 from the paper feed cassette 84.
And a friction member 102, a guide member 103 for guiding the paper 83, a transport roller 104 for inverting and transporting the fed paper 83, a transport roller 105 and a transport roller 1 pressed against the peripheral surface of the transport roller 104.
And a tip roller 106 for defining an angle at which the sheet 83 is fed from the sheet 04. The transport roller 104 is driven to rotate by a sub-scanning motor 107 via a gear train.

A printing guide member 109, which is a paper guide member for guiding the paper 83 sent from the transport roller 104 below the recording head 94 in accordance with the moving range of the carriage 93 in the main scanning direction, is provided. I have. On the downstream side of the printing receiving member 109 in the sheet conveying direction, a conveying roller 11 that is rotationally driven to send out the sheet 83 in the sheet discharging direction.
1. A spur 112 is provided, and the paper 83
The paper discharge rollers 113 and spurs 114 that feed the paper to the paper 6 and guide members 115 and 116 that form a paper discharge path are provided.

A reliability maintenance / recovery mechanism (hereinafter, referred to as a “subsystem”) 117 for maintaining and recovering the reliability of the head 94 is disposed on the right end side in the moving direction of the carriage 93. The carriage 93 is moved to the subsystem 117 side during standby for printing, and the head 94 is capped by capping means or the like.

In each of the above embodiments, the side shooter system in which the diaphragm displacement direction and the nozzle droplet ejection direction are the same has been described. However, the side shooter system in which the diaphragm displacement direction and the nozzle droplet ejection direction are orthogonal to each other. You can also In addition, the present invention, in addition to the inkjet head,
For example, the present invention can be applied to a droplet discharge head that discharges droplets other than ink, for example, a liquid resist for patterning, and further can be applied to a micromotor, a micropump, and other microactuators.

[0128]

As described above, according to the ink jet head of the present invention, since the engraved portion serving as a gap is formed on the diaphragm, the gap accuracy is improved and the variation in the ink droplet ejection characteristics is reduced. In addition, a highly accurate non-parallel gap can be easily formed.

According to the ink jet head of the present invention, the engraved portion serving as a gap is formed on the diaphragm, and the electrode is at least wider than the engraved portion and is flat within the range. The ink droplet ejection characteristics are improved, and a high-precision gap can be formed with a high process yield. In particular, a high-precision non-parallel gap can be easily formed.

In each of these ink jet heads according to the present invention, a silicon substrate is used as a substrate on which the diaphragm is formed, and the engraved portion serving as a gap is formed by thermal oxidation and removal of the portion, thereby providing a low cost and high cost. An accurate gap can be formed with good reproducibility.

According to the ink jet head of the present invention, since the engraved portion serving as a gap is formed in the insulating film formed on the surface of the vibration plate, the gap accuracy is improved, and the variation in ink droplet ejection characteristics is reduced. At the same time, a non-parallel gap with particularly high precision can be easily formed.

According to the ink jet head of the present invention, the engraved portion serving as a gap is formed in the insulating film formed on the surface of the diaphragm, and the electrode is at least wider than the engraved portion and is flat within the range. In addition, the gap accuracy is improved, the variation in the ink droplet ejection characteristics is reduced, and a high-precision gap can be formed with a high process yield. In particular, a high-precision non-parallel gap can be easily formed. become able to.

In each of these ink jet heads according to the present invention, a silicon substrate is used as the substrate for forming the vibration plate, and the silicon substrate is formed of a vibrating layer composed of a high-concentration boron diffusion layer only in an area where a carved portion or a gap is formed. Since the plate is formed, the formation of the gap and the formation of the high-concentration boron diffusion layer for the diaphragm can be performed with one mask, and the high-precision gap can be formed at a low cost by a simple process. can do.

Further, in the ink jet head according to the present invention in which the engraved portion serving as a gap is formed on the diaphragm, a silicon substrate is used as the substrate on which the diaphragm is formed, and the diaphragm is formed only on the portion serving as the gap on the silicon substrate. By forming a high-concentration boron diffusion layer for forming a gap, and forming the engraved portion serving as a gap by removing the accelerated oxide film and the oxide film, a highly accurate gap can be easily formed at low cost.

Further, in the ink jet head according to the present invention, in which the diaphragm is formed of a high-concentration boron layer, the discharge chamber is located in the region where the high-concentration boron diffusion layer is formed, so that the production yield of boron is improved. The strength of the diaphragm can be secured.

Further, since the gap formed by the engraved portion has an inclined surface having a gap length of zero in cross-sectional shape, it is possible to drive the head at a low voltage and improve the ejection characteristics.
Further, since the opening of the gap is sealed, it is possible to easily prevent water or the like from entering the gap at the time of chipping, thereby simplifying the manufacturing process. In this case, by providing a means for releasing the internal pressure of the gap to the atmospheric pressure during the production, the internal pressure of the gap can be easily released to the atmospheric pressure, and the variation in the ink droplet ejection characteristics can be suppressed.

According to the ink jet recording apparatus of the present invention, the ink jet head for jetting ink droplets is one of the above-described liquid drop ejecting heads, so that the ink jetting characteristics and the ink drop landing position accuracy are improved. And the image quality is improved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional explanatory view in a lateral direction of a diaphragm of an inkjet head according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional explanatory view of the head in a longitudinal direction of a diaphragm.

FIG. 3 is a schematic cross-sectional explanatory view in a lateral direction of a diaphragm of an inkjet head according to a second embodiment of the invention.

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

FIG. 5 is an explanatory view illustrating a manufacturing process of a silicon substrate serving as a flow path substrate of the head.

FIG. 6 is an explanatory view illustrating a manufacturing process of the electrode substrate of the head.

FIG. 7 is an explanatory view illustrating a manufacturing process of the head.

FIG. 8 is an explanatory diagram illustrating an example of a head to be compared with the head.

FIG. 9 is an explanatory diagram illustrating another example of a head to be compared with the same head.

FIG. 10 is a schematic cross-sectional explanatory view in a lateral direction of a diaphragm of an inkjet head according to a third embodiment of the invention.

FIG. 11 is an explanatory schematic cross-sectional view of the head in the longitudinal direction of the diaphragm.

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

FIG. 13 is a schematic cross-sectional explanatory view of the head in the longitudinal direction of the diaphragm.

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

FIG. 15 is an explanatory schematic sectional view of the head in the longitudinal direction of the diaphragm.

FIG. 16 is an explanatory schematic cross-sectional view of an ink jet head according to a sixth embodiment of the present invention, taken along a lateral direction of a diaphragm.

FIG. 17 is a schematic cross-sectional explanatory view of the head in the longitudinal direction of the diaphragm.

FIG. 18 is an explanatory view illustrating a manufacturing process of a silicon substrate serving as a flow path substrate of the head.

FIG. 19 is an explanatory diagram illustrating a manufacturing process of the head.

FIG. 20 is an explanatory schematic cross-sectional view of an ink jet head according to a seventh embodiment of the present invention, taken along a lateral direction of a diaphragm.

FIG. 21 is a schematic cross-sectional explanatory view of the head in the longitudinal direction of the diaphragm.

FIG. 22 is an explanatory view illustrating an example of a manufacturing process of a silicon substrate serving as a flow path substrate of the head.

FIG. 23 is an explanatory view illustrating a manufacturing process of the head.

FIG. 24 is an explanatory view illustrating another manufacturing process of the silicon substrate serving as the flow path substrate of the head.

FIG. 25 is a schematic cross-sectional explanatory view in the lateral direction of the diaphragm of the inkjet head according to the eighth embodiment of the invention.

FIG. 26 is an explanatory schematic sectional view of the head in the longitudinal direction of the diaphragm.

FIG. 27 is an explanatory view illustrating a manufacturing process of a silicon substrate serving as a flow path substrate of the head.

FIG. 28 is an explanatory diagram illustrating a manufacturing process of the head.

FIG. 29 is a schematic cross-sectional view in the transverse direction of the diaphragm of the head for comparison for explaining the relationship between the ejection chamber and the high-concentration boron layer in the ink-jet head according to the present invention.

FIG. 30 is a schematic cross-sectional view in the longitudinal direction of the diaphragm of the head for explaining the effect of sealing the gap opening in the ink jet head according to the present invention.

FIG. 31 is a schematic cross-sectional view in the longitudinal direction of the diaphragm of an example of a head for comparison, which is also used for describing the effect of sealing the gap opening.

FIG. 32 is a schematic cross-sectional view in the longitudinal direction of the diaphragm of another example of a head for comparison, which is also used for describing the effect of sealing the gap opening.

FIG. 33 is an explanatory top view of the inkjet head according to the ninth embodiment of the present invention, from which the nozzle plate is omitted.

FIG. 34 is a schematic cross-sectional explanatory view in the longitudinal direction of the diaphragm along the line AA in FIG. 33;

FIG. 35 is a schematic perspective explanatory view of a mechanism section of the ink jet recording apparatus according to the present invention.

FIG. 36 is an explanatory side sectional view of the recording apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flow path board, 3 ... Electrode board, 4 ... Nozzle plate, 5 ... Nozzle, 6 ... Discharge chamber, 10 ... Vibration plate, 12 ... Carved part, 1
5 ... electrode, 16 ... gap, 17 ... protective insulating film, 18 ...
Separation groove, 30: high-concentration boron diffusion layer, 73: open port to atmosphere.

Claims (12)

[Claims] A nozzle for discharging ink droplets, a discharge chamber communicating with the nozzle, a diaphragm forming a wall surface of the discharge chamber, and an electrode facing the diaphragm with a gap therebetween; An ink jet head for discharging an ink droplet from the nozzle by deforming and displacing the vibration plate by electrostatic force, wherein the engraved portion serving as the gap is formed in the vibration plate. A nozzle for discharging ink droplets, a discharge chamber communicating with the nozzle, a diaphragm forming a wall surface of the discharge chamber, and an electrode facing the diaphragm with a gap therebetween; In the ink jet head which discharges ink droplets from the nozzles by deforming and displacing the vibration plate by electrostatic force, a sculpture portion serving as the gap is formed in the vibration plate, and the electrode is wider than at least the sculpture portion. An inkjet head characterized by being flat within a range. 3. A nozzle for discharging ink droplets, a discharge chamber communicating with the nozzle, a diaphragm forming a wall surface of the discharge chamber, and an electrode facing the diaphragm with a gap therebetween, In the ink jet head for discharging the ink droplets from the nozzle by deforming and displacing the vibration plate by electrostatic force, the engraved portion serving as the gap is formed in an insulating film formed on the surface of the vibration plate. Ink jet head. 4. A nozzle for discharging ink droplets, a discharge chamber communicating with the nozzle, a vibration plate forming a wall surface of the discharge chamber, and an electrode facing the vibration plate via a gap, In the ink jet head which discharges ink droplets from the nozzles by deforming and displacing the vibration plate by electrostatic force, an engraved portion serving as the gap is formed in an insulating film formed on a surface of the vibration plate, and the electrode is at least formed. An ink jet head which is wider than the engraved portion and is flat within the range. 5. The ink jet head according to claim 1, wherein the substrate forming the diaphragm is a silicon substrate, and the engraved portion serving as the gap is formed by thermal oxidation and removal of the portion. An ink jet head characterized by the following. 6. The ink jet head according to claim 1, wherein the substrate on which the vibration plate is formed is a silicon substrate, and the silicon substrate is provided only in an area where the engraved portion or the gap is formed. An ink jet head comprising a diaphragm made of a high-concentration boron diffusion layer. 7. The ink jet head according to claim 1, wherein the substrate on which the vibration plate is formed is a silicon substrate, and the silicon substrate has a high-density structure in which the vibration plate is formed only in the gap portion. An ink-jet head, wherein a boron diffusion layer is formed, and the engraved portion serving as the gap is formed by accelerated oxidation of the boron diffusion layer and removal of the oxide film. 8. The ink jet head according to claim 6, wherein the discharge chamber is located in a region where the high-concentration boron diffusion layer is formed. 9. The ink jet head according to claim 1, wherein the gap formed by the engraved portion has an inclined surface having a cross-sectional shape with a gap length of zero. Ink jet head. 10. The ink jet head according to claim 1, wherein an opening of the gap is sealed. 11. The ink jet head according to claim 10, further comprising means for releasing the pressure in the gap to atmospheric pressure during the production. 12. An ink jet recording apparatus equipped with an ink jet head for discharging ink droplets, wherein the ink jet head comprises the ink jet head according to any one of claims 1 to 11.