JP2003300328A - Ink jet head and its fabricating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet head exhibiting excellent ink ejection properties, and its fabricating method, by preventing outflow of adhesive to the barrier wall of a channel substrate at the time of bonding the channel substrate and a cover substrate. <P>SOLUTION: The ink jet head having ink channels formed by covering the barrier wall 13 and the upper surface of a channel substrate 1 with a cover substrate 2 and ejecting ink in the ink channel through shear deformation of the barrier wall 13 of the ink channel is fabricated by a step for forming a metal electrode on the surface of the barrier wall 13 of the channel substrate 1, a step for superposing the cover substrate 2 on the upper end face of the barrier wall 13 such that the ink channel is formed by the barrier wall 13 and the cover substrate 2 under such a state as the hardness of adhesive is 10<SP>5</SP>dyne/cm<SP>2</SP>or above, and a step for pressing the barrier wall 13 and the cover substrate 2 such that the upper end face of the barrier wall 13 and the cover substrate 2 are bonded with the hardness of adhesive being in the range of 10<SP>5</SP>dyne/cm<SP>2</SP>and 10<SP>9</SP>dyne/cm<SP>2</SP>. <P>COPYRIGHT: (C)2004,JPO

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 having excellent curability of an adhesive, good adhesiveness, and excellent ink ejectability, and a method for producing the same.

[0002]

2. Description of the Related Art A shear mode type ink jet head is provided with a channel substrate provided with an ink flow path divided by partition walls using a polarized piezoelectric element, and a cover substrate fixed to the upper surface of the channel substrate. The partition is shear-deformed to eject ink droplets from a nozzle connected to an ink flow path, and recording is performed on a recording medium such as paper or film.

As a means for fixing the channel substrate and the cover substrate, a method is generally used in which an adhesive is applied to the cover substrate, and then the channel substrate and the cover substrate are superposed and pressed to bond them. When a plurality of members are bonded using an adhesive, in order to improve the handleability of the member to which the adhesive is applied, the applied adhesive should be B-staged and then stacked and bonded to other members. It is known that, when the channel substrate and the cover substrate are superposed, it is effective to superpose the adhesive applied to the cover substrate on the B-stage and then superpose it.
The B stage refers to a semi-cured state of the adhesive.

[0006] The inventors of the present invention, in bonding the channel substrate and the cover substrate, a method in which the adhesive applied to the cover substrate is once brought into the B stage state, and then the channel substrate and the cover substrate are overlapped and bonded. As a result of diligent study, it was found that various problems occur due to the hardness of the adhesive from the time of superposition to the time of completion of adhesion.

That is, when the channel substrate and the cover substrate are superposed on each other and pressed and bonded together, the adhesive does not have an appropriate hardness due to the problem of the wettability of the metal electrodes provided on the side surfaces of the partition walls of the channel substrate. Then, the phenomenon that the adhesive flows out through the metal electrode occurred. This tendency is particularly large when the metal electrode is formed by the vapor deposition method. Because
When the metal electrode is formed on the side surface of the partition wall by the vapor deposition method, in order to properly form the metal electrode on the side surface of the partition wall, the side surface of the partition wall is obliquely inclined with respect to the evaporation source. In many cases, the film formed by such oblique vapor deposition has a porous and columnar structure. Further, the metal film formed by vapor deposition is very active and has a characteristic that the surface is easily wetted. When such a film is used as an electrode, the adhesive coated on the cover substrate easily flows out to the electrode side from the bonding to the curing.

The adhesive flowing out to the channel substrate has an extremely fine channel structure forming the ink flow path even when the ink jet head is washed with an organic solvent or the like which dissolves it, and the ink jet head Since the shape of the ink is complicated, it is difficult to completely clean all of them, and thus the adhesive flowing out to the partition or the adhesive remaining on the partition even after cleaning causes a problem that the ejection speed of the ink is lowered. If the adhesive flows too much, there is a problem that the adhesive at the bonding portion becomes insufficient and the bonding becomes insufficient, or the injection itself cannot be performed.

Further, when the channel substrate and the cover substrate are superposed on each other and then pressure-bonded, unless the adhesive has a hardness satisfying a predetermined condition, sufficient adhesion is achieved as described above. However, there is a problem in that adhesion failure occurs and ink ejection properties deteriorate and ejection itself becomes impossible.

[0008]

SUMMARY OF THE INVENTION Therefore, according to the present invention, in bonding the channel substrate and the cover substrate, the adhesive is prevented from flowing out to the partition walls of the channel substrate, and an ink jet head excellent in ink jetting property and its manufacture. The challenge is to provide a method.

Further, other problems of the present invention will be further clarified by the following description.

[0010]

The above-mentioned problems of the present invention are solved by the following inventions.

(Claim 1) The partition wall of the channel substrate and the upper surface of the channel substrate are covered with a cover substrate to form an ink flow path, and the partition wall of the ink flow path is sheared and deformed to cause ink in the ink flow path. A method of manufacturing an inkjet head for ejecting ink, comprising: forming a metal electrode on a surface of a partition wall of the channel substrate; applying an adhesive to the cover substrate; and the adhesive satisfying Condition 1 below. In this state, a step of stacking the cover substrate on the upper end surface of the partition wall so that the partition wall and the cover substrate form an ink flow path; and the adhesive satisfies the following condition 1 and the following condition 2 A step of pressurizing the channel substrate and the cover substrate so that the upper end surface of the partition wall and the cover substrate are bonded to each other. Method of manufacturing a head. (Condition 1) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁵ dyne / cm ² or more. (Condition 2) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁵ dyne / cm ² or more and 10 ⁹ dyne / cm ² or less.

(Claim 2) The method of manufacturing an ink jet head according to claim 1, wherein the hardness of the adhesive under the condition 2 is 10 ⁶ dyne / cm ² or more and 10 ⁸ dyne / cm ² or less. .

(Claim 3) The method for producing an ink jet head according to claim 1 or 2, wherein the hardness of the adhesive under the condition 1 is 10 ⁶ dyne / cm ² or more.

(Claim 4) In the step of forming the ink flow path, a step of joining two different channel substrates so that their polarization directions are opposite to each other before the step of superposing the cover substrates. The method for manufacturing an inkjet head according to any one of claims 1 to 3, further comprising a step of processing a groove for the ink flow path in the bonded channel substrate.

(Claim 5) The pressure applied in the step of pressurizing the channel substrate and the cover substrate is 14 to 20.
method for manufacturing an ink jet head according to any one of claims 1 to 4, characterized in that a kg / cm ^2.

(Claim 6) In the step of forming the metal electrode, the metal electrode is formed on the surface of the partition wall made of a non-metallic piezoelectric material as the channel substrate. A method for manufacturing an inkjet head according to claim 1.

(Claim 7) The step of forming the metal electrode on the surface of the partition wall of the channel substrate is a step of forming the metal electrode by vapor deposition, according to any one of claims 1 to 6. Inkjet head manufacturing method.

(Claim 8) In the step of applying the adhesive, the adhesive is applied to a cover substrate obtained by depolarizing a piezoelectric element plate of the same type as the channel substrate. Item 8. A method for manufacturing an inkjet head according to any one of Items 1 to 7.

(Claim 9) A partition wall of the channel substrate and an upper surface of the channel substrate are covered with a cover substrate to form an ink flow path, and the partition wall of the ink flow path is sheared and deformed to cause ink in the ink flow path. In the inkjet head for discharging, a metal electrode is formed on the surface of the partition wall of the channel substrate, the cover substrate is coated with an adhesive, and the partition wall and the The channel substrate and the cover substrate are overlapped with each other so that an ink flow path is formed by the cover substrate, the channel substrate and the cover substrate are pressed, and the adhesive is formed under the following condition 1.
An inkjet head, which satisfies the following condition 2 and is adhered. (Condition 1) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁵ dyne / cm ² or more. (Condition 2) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁵ dyne / cm ² or more and 10 ⁹ dyne / cm ² or less.

(Item 10) The ink jet head according to Item 9, wherein the hardness of the adhesive under the condition 2 is 10 ⁶ dyne / cm ² or more and 10 ⁸ dyne / cm ² or less.

(Claim 11) The ink jet head according to Claim 9 or 10, wherein the adhesive of Condition 1 has a hardness of 10 ⁶ dyne / cm ² or more.

(Claim 12) The ink flow channel is formed by bonding two different channel substrates so that their polarization directions are opposite to each other, and the ink flow channel is connected to the bonded channel substrate. The inkjet head according to any one of claims 9 to 11, wherein a groove for use is processed.

(Claim 13) The ink jet head according to any one of claims 9 to 12, wherein the channel substrate and the cover substrate are adhered under pressure of 14 to 20 kg / cm ^2. .

(Claim 14) The ink jet head according to any one of claims 9 to 13, wherein the metal electrode is formed by vapor deposition.

(Claim 15) The channel substrate is made of a non-metallic piezoelectric material.
The inkjet head according to any one of 1.

(Claim 16) The ink jet head according to any one of claims 9 to 15, wherein the cover substrate is a substrate obtained by depolarizing a piezoelectric element plate of the same type as the channel substrate.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway perspective view showing the outline of an ink jet head, and FIG. 2 is a vertical sectional view of the same head.

In FIG. 1, 1 is a channel substrate, 2 is a cover substrate, 3 is a nozzle plate, 4 is a back plate,
Reference numeral 5 is an ink manifold.

As the piezoelectric material used for the channel substrate 1, for example, a piezoelectric material which is deformed by applying an electric field can be used, and examples thereof include a substrate made of an organic material and a non-metal substrate.

Examples of the organic material used for the substrate made of an organic material include an organic polymer such as polyvinylidene fluoride and a hybrid material of an organic polymer and an inorganic material.

Examples of the non-metallic substrate include a piezoelectric ceramics substrate formed through steps such as molding and firing, and a substrate formed without requiring molding and firing.

In the present invention, the piezoelectric material used for the channel substrate 1 is preferably a non-metal channel substrate. The reason is that non-metallic channel substrates such as piezoelectric ceramics are generally harder, have less pressure loss when deformed to generate pressure, and often have good electromechanical conversion efficiency. is there.

In a non-metal channel substrate, molding,
As a piezoelectric ceramic substrate formed through a process such as firing, for example, lead zirconate titanate (hereinafter referred to as “PZ
T "and abbreviated), more BaTiO _3, Zn
O, LiNbO ₃ , LiTaO ₃ or the like may be used.

As PZT, P containing no third component added
ZT and (PbZrO ₃ -PbTiO _3), there is a PZT added with a third component.

The third component added is Pb (Mg _{1/2
Nb 2/3) O 3, Pb (} Mn 1/3 Sb 2/3) O 3, Pb (C
o _1/3 Nb _2/3 ) O _{3 and the} like.

In the non-metal channel substrate,
The substrate formed without requiring molding and firing can be formed by, for example, a sol-gel method, a laminated substrate coating method, or the like.

The channel substrate 1 is composed of two channel substrates 1.
It is formed by joining a and 1b vertically with their polarization directions opposite to each other. Examples of means for joining the two channel substrates 1a and 1b include means for joining using an epoxy adhesive or the like.

The thickness (dry film thickness) of the adhesive layer after curing is
The range of 1 to 100 μm is preferable.

In this embodiment, the channel substrate 1 is composed of two channel substrates 1a and 1b in order to increase the amount of shear deformation, but the present invention is not limited to such a configuration. is not.

Ink is stored in the channel substrate 1 by processing a plurality of parallel rows of grooves at a predetermined pitch using a known grinder such as a disk-shaped grindstone (dicing blade). A channel portion 10 including an ink channel 11 serving as an ink flow path, an air channel 12 that does not store ink, and a partition wall 13 between the respective channel portions 10 are alternately formed.

In the present invention, in order to obtain a larger effect of the present invention, the channel height is 50 μm or more and 500 or more.
It is preferably μm or less. The aspect ratio (channel height / channel width) is preferably 1 or more and 5 or less.

Next, after the groove is processed as described above, the metal electrode 6 is formed on the wall surface of each partition wall 13. As a method of forming the metal electrode 6, known methods such as a vapor deposition method, a sputtering method, and a plating method can be used.

Since each partition wall 13 is composed of two channel substrates 1a and 1b having different polarization directions, each metal electrode 6 corresponding to each partition wall 13 has at least each partition wall 1a and 1b in order to drive both the substrates 1a and 1b. 13 is formed on the entire side surface extending over the channel substrates 1a and 1b forming the substrate 13.

As the metal capable of forming the metal electrode 6, Au, Pt, Ag, Ni, Co, Cu,
Examples of the main component include Al, and among others, Al
Those having Ni or Cu as a main component are preferable, and those having Ni as a main component are particularly preferable.

The electroless plating is particularly preferable as the plating used when the metal electrode 6 is formed by the plating method. This is because the electroless plating can easily form a more uniform and pinhole-free metal film.

In forming electrodes by electroless plating,
Ni-P (phosphorus) plating or Ni-B (boron) plating may be used alone, or Ni-P and Ni-
B may be layered.

In the case of Ni-P plating, the electrical resistance increases as the P content increases, so the P content is preferably about 1 to several percent. Since the B content of Ni-B plating is usually 1% or less, N
Ni-B is preferable to Ni-P because it has a higher Ni content than i-P, low electric resistance, and good connectivity with external wiring. However, Ni-B is expensive, so Ni-P and Ni-P are more expensive.
It is also preferable to combine B.

The metal electrode 6 made of Ni-P or Ni-B by the electroless plating method has uniform deposition and, as a result, has a smooth surface property.

The thickness of the metal electrode 6 is preferably in the range of 0.5 to 5 μm.

The metal electrode 6 is formed on the partition wall 13 by forming a plating film by, for example, electroless plating of Ni-B, and then performing electroless plating of Ni-P. You can also In this case, it is also possible to make each plating metal different.

After the plating film is formed on the partition wall 13 by electroless plating, the plating film may be subjected to electrolytic plating such as gold plating.

Further, after the metal film is formed on the partition wall 13 by the sputtering method, the vapor deposition method or the like, the metal electrode 6 is formed by performing the electrolytic plating treatment on the metal film to form the plated film. Good.

When the metal electrode 6 is formed by the vapor deposition method, after the protective film is provided on the upper end surface of the partition wall 13, the partition wall 13 is formed.
The metal serving as an electrode is evaporated from a vapor deposition source located in a plane that forms a constant angle with the extended surface of. Thereby, metal is vapor-deposited on the entire side surfaces of the channel substrates 1a and 1b forming each partition wall 13.

As the metal used as the electrode, gold, aluminum, and nickel-chromium alloy are preferable from the viewpoints of electrical characteristics, corrosion resistance, and workability.

Next, the cover substrate 2 is attached to the upper surface of the channel substrate 1 formed as described above.

As the cover substrate 2, it is preferable to use the same piezoelectric element plate as that used for the channel substrate 1 after depolarizing it, because warping, deformation, and peeling due to a difference in thermal expansion coefficient do not occur at the time of bonding.

Further, it may be a non-piezoelectric substrate having a thermal expansion coefficient similar to that of the channel substrate 1. Examples of the non-piezoelectric substrate include a ceramic substrate formed through steps such as molding and firing, a substrate formed without requiring molding and firing, and the like.

As a ceramic substrate formed through a process such as firing, for example, Al ₂ O ₃ , SiO ₂ , a mixture thereof, a mixed melt, and further ZrO ₂ , BeO, AlN, SiC.
Etc. can be used.

In addition, the non-piezoelectric substrate may be a substrate made of an organic material, or may be an organic polymer or a hybrid material of an organic polymer and an inorganic material.

In the present invention, when the channel substrate 1 and the cover substrate 2 are bonded, it is preferable to use a curable adhesive.

Examples of the curable adhesive include, but are not limited to, epoxy adhesives.

In the present invention, as described above, after the metal electrode 6 is provided on the surface of the partition wall 13 of the channel substrate 1, the cover substrate 2 is formed.
When an adhesive is applied to the substrate, the cover substrate 2 is superposed on the upper surface of the channel substrate 1 in a state where the adhesive satisfies the following condition 1, and the channel substrate 1 and the cover substrate 2 are bonded while being pressed. In addition, the adhesive satisfies the following condition 1, and the channel substrate 1 and the cover substrate 2 are bonded to each other under the following condition 2.

(Condition 1) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁵ dyne / cm ² or more. (Condition 2)
The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁵ dy
It is ne / cm ² or more and 10 ⁹ dyne / cm ² or less.

If the hardness of the adhesive is less than 10 ⁵ dyne / cm ² , there is a problem that the adhesive flows out to the metal electrode 6 when the channel substrate 1 and the cover substrate 2 are superposed on each other. This is a necessary condition from when the channel substrate 1 and the cover substrate 2 are superposed to each other until they are bonded to each other.

Further, when the channel substrate 1 and the cover substrate 2 are bonded while being pressed, it is necessary that the adhesive has tackiness. At this time, the hardness of the adhesive is 10 ⁹
If it exceeds dyne / cm ² , the adhesiveness of the adhesive will be insufficient and the adhesion between the channel substrate 1 and the cover substrate 2 will be poor.

If the upper part of the partition wall 13 is not sufficiently adhered,
When the head is driven, the generated pressure becomes smaller than that in the case where the adhesion is sufficiently performed, which causes an increase in the drive voltage and the occurrence of variations in each channel. If it gets worse, the ink may leak from the ink channel 11 and cause defective ink ejection.

In a more preferred embodiment of the present invention, after the metal electrode 6 is provided on the surface of the partition wall 13 of the channel substrate 1 as described above, the cover substrate 2 is coated with an adhesive, and the adhesive has the following Condition 3 The cover substrate 2 is superposed on the upper surface of the channel substrate 1 while satisfying the condition, and when the channel substrate 1 and the cover substrate 2 are adhered while being pressed, the adhesive satisfies the following Condition 3. In addition to being satisfied, the channel substrate 1 and the cover substrate 2 are adhered to each other under the following Condition 4.

(Condition 3) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁶ dyne / cm ² or more. (Condition 4) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁶ dyne / cm ² or more and 10 ⁸ dyne / cm ² or less.

In the present invention, the adhesive is used under the above condition 1,
Or, more preferably, when the channel substrate 1 and the cover substrate 2 are overlapped and pressed under the condition 3 above, the pressure applied is preferably 14 to 20 kg / cm ² .

The curing time is not particularly limited, but is preferably about 30 minutes to 3 days.

After the cover substrate 2 is bonded to the upper surface of the channel substrate 1 in this way, an insulating protective film for protecting the metal electrode 6 is formed in at least the ink channel 11 of the channel portion 10. Is preferred.

As the insulating protective film, insulating protective films made of various known materials can be used.
It is particularly preferable to use a parylene film. This is because when the parylene film is formed, it becomes possible to use a water-based ink as the ink. In this embodiment, this insulating protective film is referred to as a parylene film 7.

As a method for forming the parylene film 7, a known method by a CVD method (Chemical Vapor Deposition) using a solid diparaxylylene dimer as a vapor deposition source can be used. That is, the diradical paraxylylene generated by vaporization and thermal decomposition of the diparaxylylene dimer is adsorbed on the substrate and polymerized to form a film.

The parylene film 7 preferably has a thickness of 1.0 to 10 μm. Parylene film 7 has a thickness of 1.0 μm
If it is thinner, it becomes difficult to maintain a sufficient insulating property, and if the thickness exceeds 10 μm, the rigidity of the film itself restricts the movement of the partition wall 13. The more preferable range of the film thickness of the parylene film 7 is 1.0.
To 5.0 μm, and a particularly preferable range is 1.0 to 3.
It is 0 μm. Even if the parylene film 7 is formed as a sufficiently thin film in the ink channel 11, it is possible to obtain sufficient ink ejection sensitivity and ink ejection characteristics without reducing the effective sectional area in the ink channel 11. is there.

In the present invention, the surface of the parylene film 7 is preferably treated with oxygen plasma to make it hydrophilic. When air bubbles are mixed in the ink stored in the ink channel 11 in which the parylene film 7 is formed, the air bubbles may adhere to the parylene film 7 and stick to the parylene film 7, which makes it difficult for the air bubbles to escape. This is because it can be resolved.

Next, the nozzle plate 3 having the nozzle holes 31 for ejecting ink is bonded to the front end surface of the channel substrate 1 by using an epoxy adhesive or the like. Also,
An ink manifold 5 for supplying ink into the ink channel 11 is joined to the rear end surface of the channel substrate 1 through a back plate 4 having an ink introduction hole 41 using an adhesive such as an epoxy adhesive, and the inkjet Make up the head.

Although the manufacturing method of the present invention and an example of the ink jet head obtained by the manufacturing method have been described above, the present invention provides a method of forming a channel substrate by using an adhesive after providing a metal electrode on the partition wall surface of the channel substrate. The present invention can be applied to any manufacturing method of an inkjet head that adopts a technique of adhering a cover substrate to the upper surface of the channel substrate while heating and pressing the channel substrate so as to cover the channel portion, or any inkjet head.

[0079]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1-6, Comparative Example 1-5 Two PZT plates each having a thickness of 150 μm and a thickness of 900 μm
It was immersed in insulating oil heated to 50 ° C., polarized by applying a DC voltage of 10 KV, and two PZT plates were bonded with an epoxy adhesive so that the polarization directions were opposite.

Then, a positive photoresist "PMER P-LA10" manufactured by Tokyo Ohka Kogyo Co., Ltd. was formed on the surface of the PZT plate.
0 "by spin coating to a dry film thickness of 5 μm, and
Put in an oven at 00 ° C for 30 minutes to cure, then
Using a diamond blade from the surface of the ZT plate, an ink channel for the ink flow passage having a width of 70 μm and a depth of 300 μm extending in the front-rear direction and a width of 70 μ extending in the front-rear direction.
m, air channels for air grooves having a depth of 300 μm were alternately ground at intervals of 70 μm to form a channel substrate, ultrasonic cleaning was performed to remove grinding debris, and Ni—B electroless plating was performed.

In the electroless plating method, first, the degreasing liquid "PT-0" (organic acid salt 0.4% + inorganic alkali salt 0.
2% + nonionic activator 0.5%, pH = 1) for 30 seconds for washing. After washing with water, it was immersed in an etching solution "PT-1" manufactured by World Metal Co., Ltd. (inorganic acid salt 5% + ammonium sulfate 4%, fluorine salt 1.5%, pH = 2) for 30 seconds and washed with water. Later, World Metal Co., Ltd. oxidation solution "PT-2" (15% organic acid salt + 2% inorganic salt, pH =
Soak in 1) for 30 seconds. After further washing with water, stannous chloride solution "PT-3" manufactured by World Metal Co., Ltd. (0.4% organic acid salt + 0.8% inorganic acid salt + 0.6% stannous chloride + N)
aCl 3.5%, pH = 1) for 30 seconds, lightly washed with water, and then palladium chloride solution “PT-4” (organic acid salt 1% + inorganic acid salt 3% + palladium chloride 0) manufactured by World Metal Co., Ltd. It was soaked in 0.1%, pH = 1) for 45 seconds. After washing this with water, the treatments with "PT-3" and "PT-4" were repeated once again.

Next, the pretreated channel substrate is
World Metal Nickel heated to 60 ° C
The electroless plating solution of boron "Nivolon 70" was added with the surfactant "AP555" for 20 minutes to plate the channel substrate while rocking it vertically at a speed of 2.5 cm / sec. A plated metal was formed.

Then, the head is immersed in a resist stripping solution "PS" manufactured by Tokyo Ohka Kogyo Co., Ltd. to remove the resist,
On the ceramic sample mounting plate, fix the channel substrate with wax with the front wall of the plated channel substrate facing upwards, and place it on the rotating lapping plate of the High Plus wrapping machine manufactured by Nippon Engis Co., Ltd. Put,
3 while spraying diamond slurry with a particle size of 3 μm
The front wall of the channel substrate was polished for minutes to remove the plated metal.

Subsequently, the plating metal deposited on the rear wall and the bottom surface of the channel substrate was removed with a YAG laser having a wavelength of 532 nm at an energy density of about 50 J / cm ² to form a plating removal portion, whereby each channel portion was formed. The electrodes in between were separated to form head wiring.

On the other hand, the cover substrate was formed by depolarizing the same piezoelectric element plate as the channel substrate.

Eleven sets of such channel substrates and cover substrates were prepared, and the following adhesives (the types of adhesives used in each Example and Comparative Example are shown in Table 1) were applied to the respective cover substrates. Then, the temperature is raised from room temperature at a constant rate of 2 ° C./min, and the time of maintaining at 80 ° C. is changed, or the time of leaving it at room temperature (about 25 ° C.) is changed, and adhesion at the time of overlapping with the channel substrate is performed. Different states of the agent were made.

Further, at the time of pressing after superposition, the temperature is kept at room temperature without heating after superposition, or the temperature of heating after superposition is controlled so that the hardness of the adhesive at the time of pressurization varies. It was made.

The pressure applied after the channel substrate and the cover substrate were superposed on each other was 20 kg / cm ² .

(Adhesive 1) Epoxy adhesive Bisphenol A diglycidyl ether (DGEBA) Dicyandiamide (DICY) Epoxy adduct curing accelerator

(Adhesive 2) Epoxy adhesive Bisphenol A diglycidyl ether (DGEBA) Diethylenetriamine

The hardness of the adhesive coated on the cover substrate at the time of superposition and pressure application is Rheometric Scienti
It was determined by measurement with a viscoelasticity measuring instrument "ARES" manufactured by fic. However, since the measurement with the viscoelasticity measuring device cannot be performed after the cover substrate is attached to the channel substrate, the hardness of the adhesive was confirmed with the above viscoelasticity measuring device as follows.

As shown in FIG. 3, in the viscoelasticity measuring machine, the tip of the upper shaft 102 attached to the converter 101 side and the tip of the lower shaft 104 attached to the motor 103 are
Temperature control chamber 10 whose temperature is controlled by the temperature controller 105
6 are opposed to each other. This temperature controller 105
It is possible to form the same environment as the manufacturing temperature environment of the cover substrate to which the adhesive is actually applied. At the tip of the upper shaft 102 and the tip of the lower shaft 104, a disc-shaped jig 102 is provided.
a and 104a are attached so as to form a predetermined gap, and the adhesive 200 is present in the gap between the disc-shaped jigs 102a and 104a. The motor 103 and the temperature controller 105 are the computer (PC) 1
Controlled by 07, the data from the converter 101 is input to the computer 107.

When measuring the hardness of the adhesive, first, the inside of the temperature adjusting chamber 106 is controlled in the same manner as the temperature atmosphere in which each set of the cover substrate and the channel substrate is actually placed. In the gap between the disc-shaped jigs 102a and 104a, adhesive 2 is applied under the same conditions as the actual cover substrate.
00 is present. Then, in accordance with an instruction from the computer 107, the motor 103 is rotated at a predetermined frequency to rotate the lower shaft 104, and at that time, the torque transmitted to the upper shaft 101 via the adhesive 200 is detected by the converter 101. And outputs it to the computer 107, and measures the hardness of the adhesive 200 from the torque and the time lag of the torque.

After the cover substrate was attached to the channel substrate, it was washed with acetone, and the weight before and after that was measured,
The presence or absence of the uncured portion of the adhesive was confirmed.

After that, a parylene film is provided as a protective film,
The nozzle plate was joined to the front wall side, the back plate and the manifold were joined to the rear wall side, and predetermined wiring was performed to form an inkjet head.

Whether or not the channel substrate and the cover substrate were reliably adhered was determined by the presence or absence of the resonance frequency of the ink jet head and the ink ejection test.

The presence / absence of the resonance frequency can be determined by applying a voltage to the partition of the ink jet head to drive the deformation.
By utilizing the fact that the resonance frequency differs depending on the presence or absence of adhesion with the cover substrate, it is a method of checking the adhesion state by checking the presence or absence of a specific resonance frequency. When the resonance frequency is “present”, it indicates that strong adhesion is achieved over the entire head.

In the ink ejection test, the ejection voltage was measured by actually ejecting the ink and the ink drop velocity was 7 m / sec, and at the same time, the variations among the channels were compared. The low voltage indicates that the cover substrate is firmly adhered to the upper surface of the partition wall, so that the force at the time of deformation of the partition wall is used for ink ejection without loss. At the same time, this is a preferable state because the power consumption can be suppressed. Further, the occurrence of variation indicates that a defective adhesion is partially generated between each partition wall of the channel substrate and the cover substrate.

Table 1 shows the above evaluation results.

An ink ejection test of 100,000 shots was conducted on Examples 1 to 6. As a result, in Examples 1 and 5, a decrease in the overall injection speed and an increase in speed variation between channels were observed, but Examples 2 to 4 and 6
With respect to No. 3, the ejection performance was not deteriorated even when the ink was ejected for 100,000 shots, and the durability was excellent.

[0102]

[Table 1]

In Table 1, the hardness of the adhesive by the viscoelasticity measuring instrument at the time of pressurization was set to be substantially uniform, and one value was shown for each. From the hardness at the time of stacking to the hardness shown in Table 1 as the hardness at each pressurization,
Even when pressure-bonding is performed while the hardness of the adhesive changes, pressurization starts after the layers have a hardness higher than the hardness of each layer or after the state. The same evaluation results as in Table 1 were obtained even when pressure bonding was performed while the hardness of the adhesive was changed to the respective hardness values under pressure shown in Table 1.

Examples 7-12 and Comparative Examples 6-10 Since this example is formed in the same manner as in Example 1 except for the method of forming the metal electrode, the method of forming the metal electrode, and
Only the evaluation of the inkjet head formed thereby will be described.

Ink channels and air channels were ground in two bonded PZT plates, ultrasonic cleaning was performed, and then electrodes were formed by aluminum vapor deposition.

In the aluminum vapor deposition method, first, a protective film (dry film) is provided on the upper end surface (adhesion surface with the cover substrate) of each partition wall. Then, aluminum serving as an electrode is evaporated from a vapor deposition source located within a plane forming a certain angle with the extended surface of the partition wall, and aluminum is vapor deposited on the entire surface of the PZT plate.

After vapor deposition, the protective film on the upper end surface of each partition is removed. Thus, the aluminum electrode can be easily formed on each partition.

Similar to Example 1, Table 2 shows the presence / absence of resonance frequency of the ink jet head and the evaluation result of the ink ejection test.

[0109]

[Table 2]

In the above embodiments, the adhesive 1
Although an example in which an epoxy-based adhesive is used as both the adhesive 2 and the adhesive 2 is shown, the present invention is not limited to the epoxy-based adhesive and various adhesives can of course be applied.

However, it is preferable to use the epoxy adhesive because the ink resistance and fixing strength required for the ink jet head can be easily achieved. Also,
Especially when a PZT channel substrate is used, it is not desirable to keep the channel substrate at a high temperature in order to prevent adverse effects on the polarized PZT, and the epoxy adhesives used in this example are compared. It is particularly preferable to use an epoxy adhesive because it can be cured at a relatively low temperature.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of an inkjet head.

FIG. 2 is a partial sectional view of an inkjet head.

FIG. 3 is a schematic diagram of a viscoelasticity measuring machine.

[Explanation of symbols]

1: Channel substrate 2: Cover substrate 3: Nozzle plate 4: Back plate 5: Ink manifold 6: Metal electrode 7: Parylene film 10: Channel part 11: Ink channel 12: Air channel 13: Partition wall

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C057 AF93 AG45 AP02 AP03 AP14                       AP22 AP25 AP45 AP52 AP53                       AP54 AP55 AP59 BA03 BA05                       BA14

Claims (16)

[Claims] 1. A partition wall of a channel substrate and an upper surface of the channel substrate are covered with a cover substrate to form an ink flow path, and the partition wall of the ink flow path is sheared and deformed to eject ink in the ink flow path. A method of manufacturing an inkjet head, comprising the steps of forming a metal electrode on a surface of a partition wall of the channel substrate, applying an adhesive to the cover substrate, and in a state where the adhesive satisfies the following condition 1, A step of overlaying the cover substrate on an upper end surface of the partition wall so that an ink flow path is formed by the partition wall and the cover substrate; and the adhesive satisfies the following condition 1 and the partition wall through the following condition 2. A step of pressurizing the channel substrate and the cover substrate so that the upper end surface of the substrate and the cover substrate are adhered to each other. Production method. (Condition 1) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁵ dyne / cm ² or more. (Condition 2) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁵ dyne / cm ² or more and 10 ⁹ dyne / cm ² or less. 2. The hardness of the adhesive under the condition 2 is 10 ⁶ dyne.
The method for producing an ink jet head according to claim 1, wherein the density is not less than / cm ^{2 and not} more than 10 ⁸ dyne / cm ² . 3. The hardness of the adhesive under the condition 1 is 10 ⁶ dyne.
^{3. The} method for producing an inkjet head according to claim 1, wherein the inkjet head has a density of not less than / cm ² . 4. The step of forming the ink flow path, before the step of superposing the cover substrates, the step of joining two different channel substrates so that their polarization directions are opposite to each other, and the joining step. 2. The method according to claim 1, further comprising a step of processing a groove for the ink flow path on the formed channel substrate.
4. The method for manufacturing an inkjet head according to any one of 3 to 3. 5. The ink jet head manufacturing method according to claim 1, wherein the pressure applied in the step of pressurizing the channel substrate and the cover substrate is 14 to 20 kg / cm ^2. Method. 6. The step of forming the metal electrode comprises forming a metal electrode on a surface of a partition wall made of a non-metallic piezoelectric material as the channel substrate. Manufacturing method of inkjet head. 7. The ink jet head according to claim 1, wherein the step of forming the metal electrode on the surface of the partition wall of the channel substrate is a step of forming the metal electrode by vapor deposition. Production method. 8. The step of applying the adhesive comprises applying the adhesive to a cover substrate obtained by depolarizing a piezoelectric element plate of the same type as the channel substrate. 7. The method for manufacturing an inkjet head according to any one of 7. 9. An ink flow path is formed by covering a partition wall of a channel substrate and an upper surface of the channel substrate with a cover substrate, and the partition wall of the ink flow channel is sheared and deformed to eject ink in the ink flow channel. In the inkjet head, a metal electrode is formed on a surface of a partition wall of the channel substrate, the cover substrate is coated with an adhesive, and then the following condition 1 is satisfied.
In a state of satisfying the above, the partition wall and the cover substrate are superposed on the upper end surface of the partition wall so that an ink flow path is formed, the channel substrate and the cover substrate are pressed, and the adhesive is An ink jet head, characterized in that it is adhered under the following condition 2 while satisfying the following condition 1. (Condition 1) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁵ dyne / cm ² or more. (Condition 2) The hardness of the adhesive measured by a viscoelasticity measuring device is 10 ⁵ dyne / cm ² or more and 10 ⁹ dyne / cm ² or less. 10. The hardness of the adhesive under the condition 2 is 10 ⁶ dy.
The ink jet head according to claim 9, wherein the ink jet head is ne / cm ² or more and 10 ⁸ dyne / cm ² or less. 11. The adhesive of Condition 1 has a hardness of 10 ⁶ dy.
The inkjet head according to claim 9 or 10, wherein the inkjet head has a ne / cm ² or more. 12. The ink flow path is formed by joining two different channel substrates so that their polarization directions are opposite to each other, and the groove for the ink flow channel is formed in the joined channel substrate. Are processed.
11. The inkjet head according to any one of 11. 13. The ink jet head according to claim 9, wherein the channel substrate and the cover substrate are adhered under pressure of 14 to 20 kg / cm ² . 14. The ink jet head according to claim 9, wherein the metal electrode is formed by vapor deposition. 15. The ink jet head according to claim 9, wherein the channel substrate is made of a non-metallic piezoelectric material. 16. The ink jet head according to claim 9, wherein the cover substrate is a substrate obtained by depolarizing a piezoelectric element plate of the same type as the channel substrate.