JPH09109396A - Ink jet head and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the charge chemical reaction of an electrode and thereby prevent oxidation and dissolution by modifying an electrode material, to perform quality printing by maintaining the long-term stability of durable discharge characteristics, and to obtain reliability of ensuring high frequency of printing. SOLUTION: An ink jet head 1 equipped with an ink route 3 filled with ink, a nozzle hole 4 made in the wall surface of the ink route 3, a pair of electrodes 5 arranged in opposition to each other on the wall surface of the ink route 3, the electrodes 5 contain titanium and a metal whose valence of electrons is 5 or more, and the surface of the electrodes are oxidized.

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 for conducting recording by energizing a conductive ink and causing the conductive ink to boil and discharge by ink joule heat, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, ink jet printers have been widely used as output printers for home and office computers because of their quietness during recording, high-speed recording capability, and easy colorization. Such ink jet printers make ink into small droplets and eject the ink to permeate the recording paper to perform recording. The ink jet printer is roughly classified into a continuous method and an on-demand method according to a method of generating a small droplet and a control method of an ejection direction. To be done. The continuous method is, for example,
By the method disclosed in US Pat. No. 30,604,29, a small drop of ink is electrostatically attracted, and the generated small drop is subjected to electric field control according to a recording signal to selectively form the small drop on the recording paper. Since the recording is carried out by adhering the droplets, a high voltage is required to generate small droplets, and it is difficult to realize multi-nozzle, which is not suitable for high-speed recording. The on-demand system is a system disclosed in, for example, U.S. Pat. No. 3,474,120, in which an electrical recording signal is added to a piezoelectric vibration element attached to a recording head having a nozzle hole for ejecting a small droplet, This electric recording signal is converted into mechanical vibration of the piezoelectric vibrating element, and small ink droplets are ejected from the nozzle holes according to the mechanical signal to adhere to and penetrate the recording paper to perform recording. Since recording is performed by ejecting from the nozzle hole, it is not necessary to collect the small droplets unnecessary for image recording among the small droplets ejected as in the continuous method. A simpler configuration is possible compared to an ass type inkjet printer. In addition, Tokiko Sho 6
1-59911, Japanese Patent Publication No. 61-59914, and Japanese Patent Publication No. 62-11035 disclose a method of heating ink by a heating resistor to cause boiling and ejecting ink from a nozzle hole by boiling pressure. ing.

As another example of the on-demand system, the system disclosed in US Pat. No. 3,179,042 discloses a method in which a current is passed through ink through a pair of electrodes instead of using a piezoelectric vibrating element or a heating resistor. The inkjet heating method using an electric heating method is described in which the Joule heat is used to heat the ink to cause boiling and the ink is ejected from the nozzle holes by the boiling pressure. Compared with a method using a piezoelectric vibrating element or a heating resistor, this method has a feature that energy exchange efficiency is high and the structure of the inkjet head is simple, so that it is easy to realize multi-nozzle. Here, an electrically heated inkjet head using an electrically heated method (hereinafter, the electrically heated inkjet head is simply referred to as an inkjet head) will be described.

A conventional ink jet head will be described below with reference to the drawings. FIG. 11 is a cross-sectional side view of a main part of an inkjet head in the conventional example, and FIG. 12 is a schematic sectional view of electrodes of the inkjet head in the conventional example. In FIG. 11, 101 is an inkjet head in a conventional example, 2 is a substrate made of glass or the like having a mirror-finished surface, and 3 is 30 to 80 in width and height.
An ink channel 4 formed to have a thickness of 4 μm is formed in the wall surface of the ink channel 2, and a nozzle hole 5 for ejecting ink described later as a small droplet is formed on the substrate 2 and made of titanium. Electrodes 5b are arranged to face each other, 6 is a lead wire for connecting the electrode 5 to the outside, 7 is a power source for generating a drive voltage applied to the electrode 5, and 8 is for turning on / off the power source 7. A switch, 9 is an insulating layer laminated on the substrate 2 except for the electrode 5 portion, and 10 is 8 to 50 at a specific resistance of 25 ° C.
Ink having a conductivity of Ω · cm, and 11 is a recording paper which is positioned about 1 mm in front of the nozzle hole 4 and information is sequentially printed as ink dots.

In FIG. 12, 2 is a substrate, 5 is an electrode, 5
a is a first electrode and 5b is a second electrode.

A method of manufacturing the ink jet head having the above-described structure will be described below with reference to the drawings. First, a step of forming a substrate having a large number of electrodes will be described with reference to the drawings. 13A is a perspective view showing a substrate cleaning process of an inkjet head in the conventional example, FIG. 13B is a perspective view showing a titanium thin film forming process of the inkjet head in the conventional example, and FIG. 14A is a perspective view showing an electrode forming process of an inkjet head in the conventional example, FIG. 14A is a perspective view showing a lead wire forming process of the inkjet head in the conventional example, and FIG. It is a perspective view which shows the insulating film formation process of an inkjet head.
In FIG. 13, 20 is a substrate, 21 is a titanium thin film, 22
Is an electrode. In FIG. 14, 20 is a substrate, 22 is an electrode, 23 is a lead wire, and 24 is an insulating layer. First, FIG.
As shown in FIG. 3A, the substrate 20 is cleaned with steam to clean the surface. Next, as shown in FIG. 13B, a titanium thin film 21 is laminated on the surface of the substrate 20 to a thickness of 0.5 to 5 μm by using the DC sputtering method. As a forming condition, a titanium target having a purity of 99.9% or more is used, a pressure during sputtering is 3 Pa or more, and a substrate temperature is 250 ° C. or more. Next, as shown in FIG. 13C, the electrodes 22 are formed at predetermined intervals by etching or ion milling. Next, gold is laminated by a plating method or a vacuum evaporation method to a thickness of 0.1 to 1 μm, and then, as shown in FIG.
As shown in, the lead wire 23 is formed by etching or ion milling. Next, the photosensitive resin 1
After application to a thickness of ˜5 μm, the electrode portions are removed by photolithography and the insulating layer 24 is formed as shown in FIG. A polyimide resin having excellent ink resistance and insulating properties is used as the photosensitive resin. Inorganic substances such as aluminum oxide and silicon oxide may be used instead of the photosensitive resin.

Next, the step of forming the nozzle plate which forms the ink flow path and the nozzle hole will be described with reference to the drawings. 15A is a perspective view showing a pretreatment process of a nozzle plate of an inkjet head in a conventional example, and FIG. 15B is a perspective view showing an ultraviolet irradiation process of a nozzle plate of an inkjet head in a conventional example, FIG. 15C is a perspective view showing a step of etching a nozzle plate of an inkjet head in a conventional example. In FIG. 15, 25 is a nozzle plate,
Reference numeral 26 is a crystallization part, 27 is an ink flow path, and 28 is a nozzle hole. First, the nozzle plate 25 is washed as shown in FIG. The nozzle plate uses photosensitive glass. Next, as shown in FIG. 15B, the positions to be the ink flow paths and the nozzle holes are crystallized to form the crystallized portion 26. The crystallization part 26 is irradiated with ultraviolet rays and heat-treated at 400 ° C. for 1 hour in a heating furnace in the atmosphere. Next, since the crystallized portion 26 has an etching rate 100 times or more higher than that of the non-crystallized portion, the crystallized portion 26 is etched into a groove shape by performing an etching process. As the etching solution, 5% hydrogen fluoride water is used. As shown in FIG. 15C, the ink flow path 27 and the nozzle hole 28 are formed in the nozzle plate. As the nozzle plate 25, a polymer material such as a polyimide resin, an acrylic resin, or a polyethylene terephthalate resin, an insulating material such as photosensitive glass, glass, or a ceramic, a semiconductor, or a metal, an alloy, or an insulator whose surface is coated with a polymer material. , Semiconductor, etc. are used.

Finally, the step of adhering the nozzle plate and the substrate will be described with reference to the drawings. FIG. 16A is a perspective view showing a state of a nozzle plate and a substrate of an inkjet head in a conventional example, and FIG. 16B is a perspective view showing a bonded state of a nozzle plate of an inkjet head in the conventional example and a substrate. . In FIG. 16, 20
Is a substrate, 22 is an electrode, 23 is a lead wire, 24 is an insulating layer,
Reference numeral 25 is a nozzle plate, 27 is an ink flow path, and 28 is a nozzle hole. First, as shown in FIG. 16A, a nozzle plate 25 having an ink flow path 27 and a nozzle hole 28, a substrate 20 having an electrode 22 and a lead wire 23 formed thereon.
Prepare Next, as shown in FIG. 16B, the nozzle plate 25 and the substrate 20 are bonded with an adhesive. At this time, the alignment is performed so that the electrode 22 is arranged in the ink flow path 27. Further, an epoxy adhesive having good ink resistance is used as the adhesive. Ink is filled in the ink flow path 27 through a common ink chamber (not shown).

Here, the electrode material in the conventional example will be described. As electrode materials other than titanium, gold, which is a material that has an appropriate oxygen overvoltage and is excellent in corrosion resistance,
Platinum, nickel, palladium, etc. are used. However, since a large current density of 1 kA / cm ² or more is applied to the electrodes during operation of the inkjet head, when gold, platinum, nickel, or palladium is used as an electrode material, an electrochemical reaction easily occurs and oxidation or dissolution occurs, The progress tends to be fast. On the other hand, titanium is stable and is most preferably used as an electrode material, but it still suffers from considerable oxidation and dissolution, which hinders the printing life. However, since the titanium film formed under the forming conditions by the manufacturing method described above has a columnar structure, the actual surface area of the titanium surface can be increased. As a result, titanium, which is electrochemically stable and has a large actual surface area, can be used as the electrode of the inkjet head, so that the current density is reduced and the electrochemical reaction can be suppressed. Therefore, titanium having a columnar structure and a large actual surface area is most preferably used as a conventional electrode material.

The conventional ink jet head manufactured as described above will be described below with reference to the drawings. FIG. 17A is a cross-sectional side view of an essential part of the conventional inkjet head before application of an AC voltage, and FIG. 17B is a schematic view of the conventional inkjet head showing generation of ink bubbles after application of an AC voltage. 17C is a side sectional view of a part, and FIG. 17C is a side sectional view of an essential part showing ejection of ink droplets after application of an AC voltage to the inkjet head in the conventional example, and FIG. FIG. 17 is a cross-sectional side view of a main part showing disappearance of ink bubbles after the application of an AC voltage is stopped.
(E) is a cross-sectional side view of essential parts showing the filling of ink after stopping the application of the alternating voltage to the inkjet head in the conventional example. 17, 2 is a substrate, 3 is an ink flow path, 4 is a nozzle hole, 5a is a first electrode, 5b is a second electrode, 6 is a lead wire, 7 is a power supply, 8 is a switch, 9 is an insulating layer, 10 Is an ink, 11 is a recording paper, 30 is a bubble generated by boiling of the ink, and 31 is an ink droplet ejected from the ink 10.
First, as shown in FIG. 17A, the inkjet head in the conventional example has a frequency of 100 k to 5 MHz and a voltage of 10 to 40 between the first electrode 5a and the second electrode 5b made of titanium.
An AC signal of V is applied to flow an AC current of 5 to 20 mA in the ink 10. In the case of AC driving with a frequency of 2 MHz, the cycle is 500 nanoseconds. 5 in this cycle
When electricity is applied for 20 μs, the ink 10 generates Joule heat of W = I ² × R × t, and the temperature of the ink 10 is 150 to 20.
It rises to about 0 ° C. Due to the Joule heat generated at this time, the ink 10 boils and bubbles 3 are generated as shown in FIG.
0 occurs between the first electrode 5a and the second electrode 5b. Further, as shown in FIG. 17C, the bubbles 30 grow and the pressure energy of boiling causes the ink droplets 31 to be ejected from the nozzle holes 4 toward the recording paper 11. Next, FIG.
As shown in (d), the ink droplet 31 is ejected and the application of the AC signal voltage is stopped, and at the same time, the bubble 30 is rapidly cooled, reduced and disappears, and the ink ejection operation is completed. In addition, the ejected ink droplets 31 adhere to the recording paper 11 and permeate to be printed. Here, the ink 10 is supplied to the ink flow path 3 from a common ink chamber (not shown) by a capillary phenomenon.
As shown in FIG. 7E, the ink 10 is filled in the ink flow path 3. By repeating this operation, continuous printing is performed.

The ink used in the present invention may be either water-soluble or oil-soluble, but is preferably water-soluble in consideration of odor and safety. The ink contains a dye, a wetting agent, a surfactant, an antiseptic agent and the like in a solvent. As a dye,
Azo dyes, acid dyes, basic dyes, direct dyes and the like are used. As the pigment, carbon black, azo lake pigment, insoluble azo pigment, condensed azo pigment, chelate azo pigment, phthalocyanine pigment, berylene pigment, atraquinone pigment, quinacridone pigment, dioxazine pigment, thioindico pigment, isoindolinone pigment, quinophthalone pigment,
Basic dye type lake, nitro pigment, aniline black,
Fluorescent pigment, titanium oxide, iron oxide, etc. are used. As the solvent, water, ethyl alcohol, methyl alcohol, n
-Propyl alcohol, isopropyl alcohol, n-
Butyl alcohol, sec-butyl alcohol, ter
Ketones or keto alcohols such as t-butyl alcohol, isobutyl alcohol, n-pentanol, diethylene glycol, lower dialkyl ethers, acetone and diacetone alcohol, and amides such as dimethylformamide and dimethylacetamide are used. As the wetting agent, alkylene glycol such as polyethylene glycol, polypropylene glycol, butylene glycol and hexylene glycol having 2 to 6 carbon atoms, diethylene glycol lower than ethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, etc. Alkyl ether, glycerin, urea, sorbitan, sorbitol, inositol, chelating agent and the like are used. As the viscosity modifier, polyvinyl alcohol, hydroxypropyl cellulose, methyl cellulose, water-soluble acrylic resin, polyvinyl pyrrolidone, gum arabic starch, glycerin and the like are used. As the surface tension adjusting agent, diaeranolamine, triethanolamine, anionic surfactant, nonionic surfactant and the like are used. pH
As a regulator, potassium hydroxide, sodium hydroxide, diaanolamine, etc. are used. As the dispersant, proteins, natural rubbers, cellulose dielectrics, natural polymers, nonionic polymers, anionic surfactants, nonionic surfactants and the like are used. Isopropyl alcohol, polyhydric alcohol, etc. are used as a foaming agent. As the antioxidant, vitamin C, sodium sulfite, hydroquinone, pyrazolidone, hydrazine and the like are used. As the preservative, alcohol, formalin, omasin sodium and the like are used. As the conductivity-imparting agent, an alkali metal compound salt of lithium or the like, an inorganic salt such as ammonium sulfate, lithium chloride, sodium chloride or potassium chloride, an organic salt or a derivative of a quaternary organic ammonium salt is used. Examples of compounds include monoethanolamine sulfate, diethanolamine sulfate, triethanolamine sulfate, monoethanolamine nitrate, diethanolamine nitrate, triethanolamine nitrate, monoethanolamine phosphate, diethanolamine phosphate, triethanolamine phosphate. Acid salt, dimethanolamine sulfate, trimethanolamine sulfate, diethylamine sulfate, triethylamine sulfate, dimethylamine sulfate, trimethylamine sulfate, monopropylamine sulfate, dipropylamine sulfate, tripropylamine sulfate, Phenylamine sulfate, diphenylamine sulfate, dimethyleneamine sulfate, trimethyleneamine sulfate, diethyleneamine sulfate, triethyleneamine sulfate, dipropyleneamine sulfate, Propylene amine sulfate, pyridine sulfate, pyrrole sulfate or the like is used. As the surfactant, fatty acid salts, higher alcohol sulfates, liquid fatty acid sulfates, fatty alcohol phosphate esters, dibasic fatty acid ester sulfonates, fatty acid amide sulfonates, alkylallyl sulfonates, Formalin-condensed naphthalene sulfonates, alkylpyridium salts, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, polyoxyethylene sorbitan alkyl esters You can Further, a resin polymer such as an alkyd resin, an acrylic resin, an acrylamide resin, polyvinyl alcohol, or polyvinylpyrrolidone may be added in order to reinforce the strength of the ink film when attached to the printing paper. Addition of an antifungal agent is advantageous from the viewpoint of ensuring reliability during long-term storage. The specific resistance of the ink is 8 to 50 Ω · cm, preferably 15 to 25 Ω · c at 25 ° C.
m is used. When the specific resistance is less than 15 Ω · cm, the content of the conductivity-imparting agent increases, the dissolution stability of the dye decreases, and the nozzle clogging tends to deteriorate, which is not preferable. If the AC frequency of the voltage applied to the electrode is lowered as the specific resistance exceeds 25 Ω · cm, the chemical reaction on the substrate cannot be prevented, the electrode is dissolved and the ejection stability tends to be deteriorated, which is not preferable. Viscosity is 1-10 cp,
Preferably 1 to 5 cp is suitably used. Viscosity 1c
When it is less than p, it tends to be impossible to mix appropriate raw materials, which is not preferable. When the viscosity exceeds 5 cp, it is not preferable because ink droplets having an appropriate size cannot be obtained. The surface tension is 28 to 55 dyne / cm, preferably 30 to 45 dyne / cm. When the surface tension is less than 30 dyne / cm, fine line bleeding of the print is deteriorated and the print density tends to decrease, which is not preferable. When the surface tension exceeds 45 dyne / cm, the color bleeding property of color overprinting tends to decrease, which is not preferable. The pH used is 6 to 10, preferably 7 to 9. When the pH is less than 7, the dissolution stability of the dye tends to decrease, which is not preferable. As the pH exceeds 9, discoloration of the dye tends to occur, which is not preferable.

[0012]

However, in the above-mentioned conventional ink jet head, even when titanium, which has the columnar structure and which has a large actual surface area, is used most preferably as the electrode, the ink and the electrode are mediated by current during the operation of the ink jet head. An electrochemical reaction occurs between them. Further, since the ink generates Joule heat and the temperature of the ink in the vicinity of the electrode rises, there is a problem that the electrochemical reaction is promoted and the electrode is oxidized and dissolved to proceed. When the oxidation of the electrode progresses, an oxide hydrate is formed on the electrode surface. Moreover, since this oxidized hydrate has a faint structure, oxidation easily progresses from the electrode surface to the inside. There is a problem that oxidation and dissolution of this electrode cause a large resistance and a sufficient current cannot flow into the conductive ink, bubbles cannot be generated, and ink droplets cannot be ejected. Further, in the ink jet head in the conventional example, when the areas of the first electrode and the second electrode, which are a pair of electrodes, are different, the current concentrates on the electrode having a small area, and the oxidation and dissolution of the electrodes progress more and more, and the electrodes themselves disappear. In some cases, the function as an ink jet head is impaired, the number of printing lives is short, and there is a serious problem in practical use.

The present invention solves the above-mentioned conventional problems. By modifying the electrode material, the electrochemical reaction of the electrode can be suppressed and oxidation and dissolution can be prevented, and the durability is excellent and the ejection characteristics are long. Providing highly reliable inkjet heads that can perform high-quality printing while maintaining stable printing for a long period of time, and manufacture highly durable and highly reliable inkjet heads with high manufacturing yield and stability It is an object of the present invention to provide a method of manufacturing an inkjet head which is excellent in productivity and mass productivity.

[0014]

In order to solve this problem, the present invention provides an electrode containing titanium and a metal having a valence electron number of 5 or more, and the surface of the electrode is oxidized. It is composed.

As a result, it is possible to obtain an ink jet head which is less likely to undergo an oxidation reaction or a dissolution phenomenon of the electrode when a voltage is applied, and which is less likely to elute the electrode substance and has excellent durability.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink jet head according to claim 1 of the present invention is provided with an ink flow path, a nozzle hole formed in a wall surface of the ink flow path, and a wall surface of the ink flow path. An ink jet head including a pair of electrodes, wherein the electrode contains titanium and a metal having a valence number of 5 or more, and the surface of the electrode is oxidized. Since the surface of the electrode in contact with is covered with titanium and an oxide of a metal having a valence of 5 or more, extra electrons of the metal having a valence of 5 or more become free electrons, and the oxide is used as a semiconductor. You can Further, the metal element having a valence electron number of 5 or more acts on a donor atom in the n-type semiconductor of titanium oxide to improve the electrical conductivity of titanium oxide. Therefore, since oxidation and dissolution are oxidation reactions in a broad sense, electrochemical reactions such as oxidation and dissolution can be suppressed. Further, even if the oxidation progresses, the electric conductivity is higher than that of the conventional electrode, so that there is an effect that a current can be stably passed through the electrode through the ink.

According to a second aspect of the present invention, there is provided an ink jet head according to the first aspect, wherein the metal having a valence electron number of 5 or more is contained in a proportion of 0.01 to 1.0 atom%. More preferably, it is used in the range of 0.05 to 0.5 atom%. When the content is less than 0.05 atom%, the ejection performance is the same as that of the conventional electrode made of titanium, and there is a tendency that no significant effect is observed in suppressing the electrochemical reaction, which is not preferable. As the content exceeds 0.5 atom%, a dense oxide film peculiar to a metal having 5 or more valence electrons is formed on the electrode surface, which increases the resistance between the electrodes and supplies a sufficient current in the ink. It is difficult to do so, which is not preferable.

An ink jet head according to a third aspect of the present invention includes an ink flow path, a nozzle hole formed in a wall surface of the ink flow path, and a pair of electrodes arranged to face the wall surface of the ink flow path. An inkjet head provided with an electrode having a titanium film and a valence electron number of 5 stacked on the titanium film.
It is assumed that the surface of the electrode is oxidized with a metal film having a valence of 5 or more and the number of valence electrons is 5 on the surface of the electrode.
Since it is coated with a metal oxide having a valency or more, it has the effect of suppressing electrochemical reactions such as oxidation and dissolution.

According to a fourth aspect of the present invention, there is provided an ink jet head according to the third aspect, wherein the metal film having a valence number of 5 or more has a thickness of 0.02 to 0.2 μm. It is preferably used in the range of 0.05 to 0.1 μm. When the thickness is less than 0.05 μm, the ejection performance is similar to that of an ink jet head having a conventional electrode made of titanium, and there is a tendency that the effect of suppressing the electrochemical reaction of the electrode cannot be seen, which is not preferable. If the thickness exceeds 0.1 μm, the electric resistance increases, the generation of bubbles is not sufficient, and the ink ejection performance tends to deteriorate, which is not preferable.

An inkjet head according to a fifth aspect of the present invention is the inkjet head according to any one of the first to fourth aspects, wherein the metal having a valence electron number of 5 or more is niobium, tantalum, tungsten, or antimony. As described above, it has a function of forming a solid solution by sufficiently forming a solid solution in titanium and easily forming a metal film on the titanium surface.

According to a sixth aspect of the present invention, there is provided an ink jet head manufacturing method, which includes an electrode film forming step of forming an electrode film containing titanium and a metal having a valence number of 5 or more, and an electrode film forming step. And an oxidation treatment step of oxidizing the surface of the electrode film to form a surface oxide layer, which has the function of forming an electrode having excellent durability without causing an oxidation reaction or a dissolution phenomenon. .

According to a seventh aspect of the present invention, in the ink jet head manufacturing method of the sixth aspect, the oxidation treatment step is
It is said that it comprises a treatment step of heating the electrode film in a temperature range of 0 to 800 ° C., and particularly preferably 400 to 500.
A range of ° C is used. When the heating temperature is lower than 400 ° C., the electrode surface is not sufficiently oxidized, and when the inkjet head is operated, there is a tendency that there is no effect of suppressing the electrochemical reaction of the electrode, which is not preferable. When the heating temperature exceeds 500 ° C., the amount of oxidation of titanium increases, volume expansion occurs, and the surface area of the electrode decreases, so that the current density increases and the effect of suppressing the electrochemical reaction of the electrode tends not to be observed, which is preferable. Absent.

According to an eighth aspect of the present invention, in the ink jet head manufacturing method of the sixth aspect, the oxidation treatment step comprises a treatment step of anodizing the electrode film.
This has the effects of simplifying the manufacturing apparatus, increasing the production speed, and producing products with stable quality, and increasing the production yield.

According to a ninth aspect of the present invention, in the ink jet head manufacturing method according to the sixth aspect, the oxidation treatment step includes a treatment step of oxidizing the electrode film with oxygen plasma, so that the product is less contaminated by impurities. It has an effect that a high quality product can be obtained.

According to a tenth aspect of the present invention, there is provided a method of manufacturing an ink jet head, wherein a titanium film forming step of forming a titanium film, and a metal film having a valence number of 5 or more on the titanium film formed in the titanium film forming step. And a titanium film forming step of heating the titanium film and the metal film formed in the metal film forming step at a temperature of 300 to 800 ° C. to form a surface oxide layer. The heating temperature in the oxidation step is particularly preferably 40
A range of 0-500 ° C is used. Heating temperature is 400 ℃
When the amount is less than the above range, the electrode surface is not sufficiently oxidized, and when the inkjet head is operated, the effect of suppressing the electrochemical reaction of the electrode tends to be unfavorable. Heating temperature is 50
When the temperature exceeds 0 ° C., the amount of oxidized titanium increases, the volume expansion occurs, and the surface area of the electrode decreases, so that the current density increases and a large effect on suppressing the electrochemical reaction of the electrode tends not to be seen, which is not preferable.

In the method of manufacturing an ink jet head according to claim 11, a titanium film forming step of forming a titanium film, and a metal having a valence number of 5 or more on the titanium film formed in the titanium film forming step. It is provided with a coating step of coating a solution containing it, and a thermal decomposition treatment step of thermally decomposing a solution containing a metal having a valence number of 5 or more applied in the coating step. The film can be oxidized, and at the same time, a metal having a valence number of 5 or more can be diffused inside the titanium film to form a metal film having high bonding strength and to be uniformly oxidized and have a stable oxidized state.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a sectional side view of an essential part of an inkjet head according to a first embodiment of the present invention.
FIG. 3 is a schematic view of a main part of an electrode of the inkjet head according to the first embodiment of the present invention. In FIG. 1, 1 is the first
Inkjet head in the embodiment, 2 is a substrate,
3 is an ink flow path, 4 is a nozzle hole, 5 is an electrode, and 5a is a first
An electrode, 5b is a second electrode, 6 is a lead wire, 7 is a power source, 8 is a switch, 9 is an insulating layer, and 10 is ink.

In FIG. 2, 2 is a substrate, 5 is an electrode, and 5a.
Is a first electrode and 5b is a second electrode. These are the same as those in the conventional example, and the same reference numerals are given to omit the description. In the first embodiment, the electrode 5 contains titanium containing 0.01% niobium, tantalum, tungsten, and antimony, respectively.
It differs from the comparative example in that it contains 0.1 and 1.0 atomic% and that the electrode surface is heated and oxidized.

As the substrate 2, an insulating material such as glass or ceramics, a semiconductor, a metal whose surface is coated with a high resistance material, a metal alloy, an insulator or a semiconductor is used. As the glass, potassium lime glass, borosilicate glass, crown glass, zinc crown glass, soda potassium glass, barium borosilicate glass, 96% silicate glass, 99.5% silicate glass phosphate glass, low melting point glass, lithium silicate glass, zinc Aluminum silicate glass, zirconium silicate glass, etc. are used. As ceramics, aluminum oxide (alumina), titanium oxide (titania), MgO.SiO ₂
(Steatite), 2MgO.SiO ₂ (holsterite), BeO (beryllia), MgO.Al ₂ O ₃ (spinel) and the like. Examples of the semiconductor include silicon, silicon carbide, germanium and the like.

As the insulating layer 9, an insulating organic material such as a heat-resistant polyimide resin, a polyamideimide resin, a urea resin, a phenol resin, an epoxy resin, a fluororesin, an acrylic resin, a silicon resin, or an insulating inorganic material is used. To be

A method of manufacturing the ink jet head of the first embodiment having the above structure will be described below with reference to the drawings. The method of manufacturing the inkjet head according to the present embodiment is the same as the conventional example except for the electrode forming step, and thus the description of the other steps will be omitted.
FIG. 3A is a process diagram for cleaning the substrate of the inkjet head according to the first embodiment, and FIG. 3B contains a metal having a valence number of 5 or more in the inkjet head according to the first embodiment. 3C is a process diagram of forming a titanium thin film, FIG. 3C is a process diagram of forming electrodes of a substrate of the inkjet head in the first embodiment, and FIG. 4A is a process diagram of forming a substrate of the inkjet head in the first embodiment. FIG. 4B is an oxidation process diagram, FIG. 4B is a lead wire formation process diagram of the substrate in the first embodiment, and FIG.
FIG. 7 is a process diagram of forming an insulating layer on a substrate of an inkjet head in the embodiment. In FIG. 3, 20 is a substrate and 21
Is a titanium thin film, and 22 is an electrode. In FIG.
Is a substrate, 22 is an electrode, 23 is a lead wire, and 24 is an insulating layer. First, as shown in FIG. 3A, the substrate 20 was subjected to ultrasonic cleaning and vapor cleaning with an organic solvent. Next, as shown in FIG. 3B, a titanium thin film 21 is laminated by DC sputtering with titanium containing 0.01, 0.1 and 1.0 atomic% of niobium, tantalum, tungsten and antimony. did. As molding conditions, the pressure is 3 Pa or more in an argon gas atmosphere, the substrate temperature is 250 ° C. or more,
The titanium thin film 21 has a thickness of 0.5 to 5.0 μm. As a method for forming the titanium thin film 21, a vacuum thin film forming technique such as a DC sputtering method, an RF sputtering method, or a vacuum evaporation method is used. Next, as shown in FIG. 3C, a titanium thin film 21 was formed on the electrode 22 of 30 × 40 μm by photolithography. At this time, the distance between the electrodes 22 was 3 μm. Next, as shown in FIG. 4A, the electrode 22 was heated to form an oxide layer on the surface.
The heating conditions were as follows: oxidation was performed by leaving it in a heating furnace at 500 ° C. for 15 minutes. The appearance of the electrode 22 was blackened and an oxide layer was formed. Next, as shown in FIG. 4B, a lead wire 23 made of gold was formed by a plating method. The thickness of the lead wire 23 was 0.1 to 1 μm. Next, the insulating layer 24 made of a photosensitive resin was formed by photolithography. As shown in FIG. 4C, the insulating layer 24 was not formed between the electrodes 22. The thickness of the insulating layer 24 is 3 μm
And A polyimide resin having excellent ink resistance and insulating properties was used as the photosensitive resin.

The performance evaluation of the ink jet head having the above structure will be described below. As a durability test of the inkjet head, the number of printing lifespan was measured. The definition of the number of printing lifespan is that the size of the ink dot on the paper surface is 70% or less compared to the beginning of printing or 13
The print life was defined as when it reached 0% or more, and the number of ejections of dots printed up to that point was measured. The applied AC voltage is 25V,
The applied AC voltage frequency was 3 MHz and the printing cycle was 5 kHz. The specific resistance of the ink used was 20 Ω · cm. The results are shown in (Table 1). Further, the specific resistance of the electrodes was measured, and the results are shown in (Table 2).

[0033]

[Table 1]

[0034]

[Table 2]

As a comparative example, the electrodes are niobium, tantalum,
0.001 of tungsten and antimony, 1.5 atom%
Titanium was included, titanium alone was subjected to an oxidation treatment, and titanium was not subjected to an oxidation treatment. Other configurations were the same as in the first embodiment.

As is clear from (Table 1) and (Table 2), it was found that the present embodiment has a printing count of 200 million or more and is excellent in durability. Resistivity is 1450-180
It was found to be in the range of 0 μΩ · cm, which was slightly smaller than that of the comparative example, and the conductivity was increased. Further, it was found that in the present embodiment, no change in appearance was observed before and after the test, and neither oxidation nor dissolution occurred.

In the present embodiment, the heat treatment is performed in the atmosphere, but if the heat treatment time is extended even in vacuum, the same oxide layer can be formed and an ink jet head having a long printing life can be realized.

As described above, according to the present embodiment, niobium, tantalum, tungsten and antimony are added in an amount of 0.01 to 0.01%.
Since the electrode made of titanium whose content is 1.0 atomic% and whose surface is heated and oxidized is provided, the electrode is not oxidized or dissolved, and the change over time is small, the printing life is long, and the durability can be improved.

(Embodiment 2) FIG. 5 is a schematic view of an essential part of an electrode of an ink jet head according to a second embodiment of the present invention. In FIG. 5, 2 is a substrate, 40 is an electrode, 41
Is a titanium film, 42 is niobium, tantalum, tungsten,
Also, a metal film containing any one of antimony and having a thickness of 0.02 to 0.2 μm whose surface is oxidized, 43a is a first electrode, and 43b is a second electrode. The ink jet head in the second embodiment is different from the first embodiment only in the configuration of the electrodes, and the other configurations are the same, so the description thereof will be omitted. In the second embodiment, the electrode 40 is the titanium film 4
1 and titanium film 41 with niobium, tantalum, tungsten, and antimony at 0.02, 0.05, and 0.
A metal film is formed by stacking layers with a thickness of 1, 0.2 μm and then oxidizing the surface.

A method of manufacturing the ink jet head of the second embodiment having the above structure will be described below with reference to the drawings. The method of manufacturing the inkjet head according to the present embodiment is the same as the conventional example except for the electrode forming step, and thus the description of the other steps will be omitted.
FIG. 6A is a process diagram for cleaning the substrate of the inkjet head in the second embodiment, FIG. 6B is a process diagram for forming a titanium thin film in the inkjet head in the second embodiment, and FIG. 6] is a process diagram of forming a metal thin film of the inkjet head in the second embodiment.
7D is a process diagram of forming electrodes on the substrate of the inkjet head in the second embodiment, FIG. 7A is a process diagram of oxidizing the substrate of the inkjet head in the second embodiment, and FIG. FIG. 7 is a process diagram of forming a lead wire of an inkjet head according to the second embodiment.
FIG. 6C is a process diagram of forming an insulating layer on a substrate of an inkjet head according to the second embodiment. In FIG. 6, 20
Is a substrate, 40 is an electrode, 44 is a titanium thin film, and 45 is a metal thin film. In FIG. 7, 20 is a substrate, 23 is a lead wire, 24 is an insulating layer, and 40 is an electrode. First, FIG.
As shown in (a), the substrate 20 was subjected to ultrasonic cleaning and vapor cleaning with an organic solvent. Next, as shown in FIG. 6B, titanium was deposited on the substrate 20 by the DC sputtering method to form a titanium thin film 44. As molding conditions,
In an argon gas atmosphere, the pressure is 3 Pa or higher, the substrate temperature is 250 ° C. or higher, and the titanium thin film 44 has a thickness of 0.5 to 5.0.
μm. Next, as shown in FIG. 6C, niobium,
Any one of tantalum, tungsten, and antimony was laminated on the titanium thin film 44 by the DC sputtering method to form the metal thin film 45. The molding condition is a purity of 99.
Using 9% or more of each metal as a target material, the vacuum pressure was 1 to 2 Pa and the substrate temperature was 100 to 250 ° C. FIG.
As shown in (d), the titanium thin film 44 and the metal thin film 45 are formed on the electrode 4 of 30 × 40 μm by photolithography.
Formed to 0. At this time, the interval between the electrodes 40 was set to 3 μm. Next, as shown in FIG. 7A, the electrode 40 was heated to form an oxide layer on the surface. The heating conditions were as follows: oxidation was performed by leaving it in a heating furnace at 500 ° C. for 15 minutes. Next, FIG.
As shown in (b), the lead wire 23 made of gold was formed by a plating method. The thickness of the lead wire 23 is 0.1 to 1 μm
And Next, as shown in FIG. 4C, an insulating layer 24 made of a photosensitive resin was formed by photolithography. A polyimide resin having excellent ink resistance and insulating properties was used as the photosensitive resin.

The performance evaluation of the ink jet head having the above structure will be described below. The printing life and specific resistance of the inkjet head of the second embodiment were measured in the same manner as the inkjet head of the first embodiment, and the results are shown in (Table 3) and (Table 4).

[0042]

[Table 3]

[0043]

[Table 4]

As a comparative example, niobium, tantalum, tungsten, and antimony are used for the metal film, and each is 0.0
One having a thickness of 1 and 0.3 .mu.m, a titanium element having an oxidation treatment and a titanium element having no oxidation treatment were prepared, and other configurations were the same as those in the second embodiment. Printing life and specific resistance were measured in the same manner.

As is clear from (Table 3) and (Table 4), it has been found that the number of printings is 200 million or more and the durability is excellent in the present embodiment. Resistivity is 2450-280
It was found to be in the range of 0 μΩ · cm, which was slightly smaller than that of the comparative example, and the conductivity was increased. Further, it was found that in the present embodiment, no change in appearance was observed before and after the test, and neither oxidation nor dissolution occurred.

In the present embodiment, the heat treatment is performed in the atmosphere, but if the heat treatment time is extended even in vacuum, the same oxide layer can be formed and an ink jet head having a long printing life can be realized.

As described above, according to the present embodiment, niobium, tantalum, tungsten, and antimony are added in an amount of 0.02 to 0.02.
Since the electrodes in which the surfaces of the metal film, the titanium film, and the metal film, which are laminated by 0.2 μm, are heated and oxidized are provided, the electrodes are not oxidized or dissolved, the change with time is small, the printing life is long, and the durability can be improved.

(Third Embodiment) FIG. 8 is a schematic view of a main part of an electrode of an ink jet head according to a third embodiment of the present invention. In FIG. 8, 2 is a substrate, 50 is an electrode, and 51.
Is a titanium film, 52 is niobium, tantalum, tungsten,
A metal film containing any one of antimony and having a thickness of 0.02 to 0.2 μm whose surface is oxidized, 53a is a first electrode, and 53b is a second electrode. The ink jet head in the third embodiment is different from the first embodiment only in the structure of the electrodes, and the other structures are the same, so the description thereof will be omitted. In the third embodiment, the electrode 50 is the titanium film 5
1 and titanium film 51 as a whole with niobium, tantalum, tungsten and antimony at 0.02, 0.05 and 0.
After coating with a thickness of 1 and 0.2 μm, the surface is oxidized to form a metal film.

A method of manufacturing the ink jet head of the third embodiment having the above structure will be described below with reference to the drawings. The method of manufacturing the inkjet head according to the present embodiment is the same as the conventional example except for the electrode forming step, and thus the description of the other steps will be omitted.
FIG. 9A is a process drawing of the substrate of the inkjet head according to the third embodiment, FIG. 9B is a process drawing of the titanium thin film of the inkjet head according to the third embodiment, and FIG. 10A is a process diagram of forming electrodes on a substrate of an inkjet head according to the third embodiment, FIG. 10A is a process diagram of forming a metal film on a substrate of an inkjet head according to the third embodiment, and FIG. FIG. 10A is a process drawing of forming a lead wire on a substrate in the third embodiment, and FIG. 10C is a process drawing of forming an insulating layer on a substrate of an inkjet head according to the third embodiment. In FIG. 9, 20 is a substrate, 44 is a titanium thin film, and 51 is a titanium film. In FIG. 10, 20 is a substrate, 23 is a lead wire, 24 is an insulating layer, 50 is an electrode, and 52 is a metal film.
First, as shown in FIG. 9A, the substrate 20 was subjected to ultrasonic cleaning and vapor cleaning with an organic solvent. Next, FIG.
As shown in (b), titanium was sputtered on the substrate 20 by a DC sputtering method to form a titanium thin film 44.
As the molding condition, the pressure is set to 3P in an argon gas atmosphere.
The substrate temperature was 250 ° C. or higher, and the thickness of the titanium thin film 44 was 0.5 to 5.0 μm. Next, as shown in FIG. 9C, a titanium thin film 44 was formed on the titanium film 51 of 30 × 40 μm by photolithography. At this time, the titanium film 51 was arranged at an interval of 3 μm. Next, a solution prepared by mixing 1 g of niobium chloride, 10 cc of unsaturated oil such as lavender oil or anise oil as a reducing agent, and 50 cc of polyhydric alcohol such as isopropyl alcohol or butanol as an organic solvent was spin-coated on the substrate 20. Spin coating conditions were 3000 rpm for 30 seconds. After that, the substrate 20 coated with the solution is left at 80 ° C. for 15 minutes to vaporize isopropyl alcohol, and then at 500 ° C. for 15 minutes.
10 (a), heat treatment is performed under the condition of minutes to decompose by heat.
A metal film 52 was formed as shown in FIG. In the thermal decomposition treatment step, thermal decomposition is performed in a heating furnace under an air atmosphere.
The thermal decomposition temperature is 300 to 800 ° C., and more preferably 40.
A temperature range of 0-500 ° C is used. Heating temperature is 40
When the temperature is lower than 0 ° C., the adhesion of a metal having a valence electron number of 5 or more to the titanium film is weak and the metal tends to be peeled off during operation, resulting in poor durability. Heating temperature is 500
As the temperature exceeds 0 ° C., the amount of oxidation of the titanium film increases, volume expansion occurs, and the surface area of the electrode decreases, so that it is difficult to stack a metal having a valence number of 5 or more on the titanium film, which is not preferable. Although the case of niobium has been described here, other tantalum, tungsten, and antimony chlorides were used to form the films at four levels of 0.02, 0.05, 0.1, and 0.2. Next, as shown in FIG. 10B, a lead wire 23 made of gold was formed by a plating method. The thickness of the lead wire 23 was 0.1 to 1 μm. Next, FIG.
As shown in (c), the insulating layer 24 made of a photosensitive resin was formed by photolithography. A polyimide resin having excellent ink resistance and insulating properties was used as the photosensitive resin.

The performance evaluation of the ink jet head having the above structure will be described below. The printing life and the specific resistance of the inkjet head of the third embodiment were measured in the same manner as the inkjet head of the first embodiment, and the results are shown in (Table 5) and (Table 6).

[0051]

[Table 5]

[0052]

[Table 6]

As a comparative example, niobium, tantalum, tungsten, and antimony were used for the metal film, and each was 0.0
One having a thickness of 1 and 0.3 μm, a layer of titanium which was subjected to an oxidation treatment and a layer of which titanium was not subjected to the oxidation treatment were prepared, and other configurations were the same as those of the third embodiment. Printing life and specific resistance were measured in the same manner.

As is clear from (Table 5) and (Table 6), it was found that the present embodiment has a printing count of 200 million or more and is excellent in durability. Specific resistance is 2100-230
It was found to be in the range of 0 μΩ · cm, which was slightly smaller than that of the comparative example, and the conductivity was increased. Further, it was found that in the present embodiment, no change in appearance was observed before and after the test, and neither oxidation nor dissolution occurred.

As described above, according to the present embodiment, niobium, tantalum, tungsten and antimony are added in an amount of 0.02 to 0.02.
Since the electrodes in which the surfaces of the metal film, the titanium film, and the metal film, which are laminated by 0.2 μm, are heated and oxidized are provided, the electrodes are not oxidized or dissolved, the change with time is small, the printing life is long, and the durability can be improved.

[0056]

As described above, according to the present invention, the ink flow path filled with ink, the nozzle hole formed in the wall surface of the ink flow path, and the pair of ink flow paths disposed opposite to the wall surface of the ink flow path. An ink-jet head including the electrode according to claim 1, wherein the electrode contains titanium and a metal having a valence number of 5 or more, and the surface of the electrode is oxidized. The electrochemical reaction is suppressed and the electrical characteristics of the electrode are stable, and the deterioration of printing over time is small and the durability is excellent. Further, since the electric conductivity is high, the current flows stably, the generation of bubbles is stabilized, and an ink jet head having excellent printing characteristics can be realized.

Further, according to the present invention, an electrode film forming step of forming an electrode film containing titanium and a metal having a valence electron number of 5 or more, and a surface of the electrode film formed in the electrode film forming step are oxidized. Since the oxidation treatment process for forming the oxide layer is provided, electrochemical reactions such as electrode oxidation and dissolution are suppressed, and the durability is excellent and the printing life and printing accuracy are high, the manufacturing yield is high, and the productivity and mass productivity are high. It is possible to realize an excellent inkjet head manufacturing method.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an essential part of an inkjet head according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a main part of an electrode of the inkjet head according to the first embodiment of the present invention.

FIG. 3A is a diagram illustrating a step of cleaning the substrate of the inkjet head according to the first embodiment. FIG. 3B is a step of forming a titanium thin film containing a metal having a valence number of 5 or more in the inkjet head according to the first embodiment. FIG. (C) Electrode forming process diagram of the substrate of the inkjet head according to the first embodiment

4A is a process diagram of oxidizing the substrate of the inkjet head according to the first embodiment; FIG. 4B is a process diagram of forming lead wires of the substrate according to the first embodiment; and FIG. 4C is a substrate of the inkjet head according to the first embodiment. Of insulating layer formation process

FIG. 5 is a schematic view of an essential part of an electrode of an inkjet head according to a second embodiment of the present invention.

FIG. 6A is a process diagram of cleaning a substrate of an inkjet head according to the second embodiment. FIG. 6B is a process diagram of forming a titanium thin film of the inkjet head according to the second embodiment. FIG. 6C is a process diagram of an inkjet head according to the second embodiment. Metal thin film forming process diagram (d) Electrode forming process diagram of the substrate of the inkjet head in the second embodiment

FIG. 7A is a process diagram of oxidizing a substrate of an inkjet head according to the second embodiment; FIG. 7B is a process diagram of forming lead wires of an inkjet head according to the second embodiment; and FIG. 7C is a process diagram of an inkjet head according to the second embodiment. Substrate insulation layer formation process diagram

FIG. 8 is a schematic view of a main part of an electrode of an inkjet head according to a third embodiment of the present invention.

FIG. 9A is a process drawing of a substrate of an inkjet head according to the third embodiment. FIG. 9B is a titanium thin film forming process drawing of the inkjet head according to the third embodiment. FIG. 9C is an inkjet head according to the third embodiment. Substrate electrode formation process diagram

10A is a process diagram of forming a metal film on a substrate of an inkjet head according to the third embodiment. FIG. 10B is a process diagram of forming a lead wire on a substrate according to the third embodiment. FIG. 10C is an inkjet head according to the third embodiment. Process diagram of insulating layer formation on the substrate

FIG. 11 is a sectional side view of a main part of an inkjet head in a conventional example.

FIG. 12 is a schematic sectional view of electrodes of an inkjet head in a conventional example.

13A is a perspective view showing a substrate cleaning process of an inkjet head in a conventional example, FIG. 13B is a perspective view showing a titanium thin film forming process of an inkjet head in a conventional example, and FIG. 13C is an electrode forming process of an inkjet head in a conventional example. Perspective view showing

FIG. 14A is a perspective view showing a lead wire forming process of an inkjet head in a conventional example. FIG. 14B is a perspective view showing an insulating film forming process of an inkjet head in a conventional example.

15A is a perspective view showing a pretreatment process of a nozzle plate of an inkjet head in a conventional example. FIG. 15B is a perspective view showing an ultraviolet irradiation process of a nozzle plate of an inkjet head in a conventional example. FIG. 15C is an inkjet head in a conventional example. Perspective view showing the etching process of the nozzle plate of FIG.

FIG. 16A is a perspective view showing a state of a nozzle plate and a substrate of an inkjet head in a conventional example. FIG. 16B is a perspective view showing a bonded state of a nozzle plate of an inkjet head and a substrate in a conventional example.

FIG. 17A is a cross-sectional side view of a main part of the conventional inkjet head before application of an AC voltage, and FIG. 17B is a cross-sectional side view of a main part of the inkjet head of the conventional example showing generation of ink bubbles after application of an AC voltage. c) Cross-sectional side view of essential parts showing ejection of ink droplets after application of AC voltage to inkjet head in conventional example. (d) Cross-sectional side view of essential parts showing disappearance of ink bubbles after stopping application of AC voltage in inkjet head in conventional example. (E) A cross-sectional side view of essential parts showing filling of ink after stopping application of an alternating voltage to an inkjet head in a conventional example

[Explanation of symbols]

 1 Inkjet head 2 Substrate 3 Ink flow path 4 Nozzle hole 5 Electrode 5a First electrode 5b Second electrode 6 Lead wire 7 Power supply 8 Switch 9 Insulating layer 10 Ink 11 Recording paper 20 Substrate 21 Titanium thin film 22 Electrode 23 Lead wire 24 Insulating layer 25 Nozzle Plate 26 Crystallized Part 27 Ink Flow Path 28 Nozzle Hole 30 Bubble 31 Ink Drop 40 Electrode 41 Titanium Film 42 Metal Film 43a First Electrode 43b Second Electrode 44 Titanium Thin Film 45 Metal Thin Film 50 Electrode 51 Titanium Film 52 Metal Film 53a First electrode 53b Second electrode 101 Conventional inkjet head

Claims (11)

[Claims] 1. An ink jet head comprising an ink flow path, a nozzle hole formed in a wall surface of the ink flow path, and a pair of electrodes arranged so as to face the wall surface of the ink flow path. The inkjet head is characterized in that the electrode contains titanium and a metal having a valence electron number of 5 or more, and the surface of the electrode is oxidized. 2. A metal having a valence electron number of 5 or more is 0.01
The ink jet head according to claim 1, wherein the ink is contained in a proportion of ˜1.0 at%. 3. An ink jet head comprising an ink flow path, a nozzle hole bored in the wall surface of the ink flow path, and a pair of electrodes arranged so as to face the wall surface of the ink flow path. And an electrode in which the electrode is formed of a titanium film and a metal film laminated on the titanium film and having a valence electron number of 5 or more, and the surface of the electrode is oxidized. head. 4. The ink jet head according to claim 3, wherein the metal film having a valence electron number of 5 or more has a thickness of 0.02 to 0.2 μm. 5. The metal having a valence number of 5 or more is any one or more of niobium, tantalum, tungsten, and antimony. The described inkjet head. 6. An electrode film forming step of forming an electrode film containing titanium and a metal having a valence number of 5 or more, and a surface of the electrode film formed in the electrode film forming step by oxidizing the surface. An inkjet head manufacturing method, comprising: an oxidation treatment step of forming an oxide layer. 7. The method of manufacturing an ink jet head according to claim 6, wherein the oxidation treatment step includes a treatment step of heating the electrode film in a temperature range of 300 to 800 ° C. 8. The method of manufacturing an ink jet head according to claim 6, wherein the oxidation treatment step includes a treatment step of anodizing the electrode film. 9. The method for manufacturing an ink jet head according to claim 6, wherein the oxidation treatment step comprises a treatment step of oxidizing the electrode film with oxygen plasma. 10. A titanium film forming step of forming a titanium film, and a metal film forming step of laminating a metal film having a valence number of 5 or more on the titanium film formed in the titanium film forming step, The titanium film and the metal film formed in the titanium film forming step and the metal film forming step are
An inkjet head manufacturing method comprising: an oxidation treatment step of forming a surface oxide layer by heating at a temperature of 800 ° C. 11. A titanium film forming step of forming a titanium film, and a coating step of applying a solution containing a metal having a valence number of 5 or more on the titanium film formed in the titanium film forming step. And a thermal decomposition treatment step of thermally decomposing the solution containing a metal having a valence electron number of 5 or more applied in the applying step, the manufacturing method of the inkjet head.