JP2790844B2 - Liquid jet recording head - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid jet recording head, and more particularly, to protection of a heating portion or an electrode portion of a bubble jet type ink jet head.

2. Description of the Related Art Non-impact recording methods have recently attracted attention in that the generation of noise during recording is extremely small to a negligible level. Among them, the so-called ink jet recording method, which can perform high-speed recording and can perform recording on so-called plain paper without requiring a special fixing process, is an extremely powerful recording method. Some have been proposed, and some have been commercialized with improvements, while others are still being put to practical use.

In such an ink jet recording method, recording is performed by flying droplets of a recording liquid called so-called ink and attaching the droplets to a recording member. The control method for controlling the flying direction of the generated recording liquid droplet is roughly classified into several types.

First, the first system is, for example, a system disclosed in US Pat. No. 3,060,429 (Tele type system) in which droplets of a recording liquid are electrostatically attracted, and the generated droplets of the recording liquid are generated. Is controlled by an electric field according to a recording signal, and recording is performed by selectively adhering a recording liquid droplet onto a recording member.

More specifically, in more detail, an electric field is applied between the nozzle and the accelerating electrode to discharge a uniformly charged droplet of the recording liquid from the nozzle, and the discharged droplet of the recording liquid is converted into a recording signal. In accordance with this, the recording is performed by causing the droplets to fly between the xy deflection electrodes configured so as to be electrically controllable and selectively adhering small droplets to the recording member by a change in the intensity of the electric field.

The second method is described, for example, in US Pat. No. 3,596,275,
A method (Sweet method) disclosed in U.S. Pat. No. P3298030 and the like, in which a droplet of a recording liquid whose charge amount is controlled by a continuous vibration generation method is generated, and the generated charge amount is controlled. The droplet is made to fly between the deflection electrodes to which a uniform electric field is applied, thereby performing recording on the recording member.

More specifically, a charging electrode configured so that a recording signal is applied in front of an orifice (ejection port) of a nozzle, which is a part of a recording head provided with a piezoelectric vibrating element, is separated by a predetermined distance. The piezoelectric vibrating element is mechanically vibrated by applying an electric signal of a constant frequency to the piezoelectric vibrating element, and a droplet of the recording liquid is discharged from the discharge port. At this time, a charge is electrostatically induced in the recording liquid droplet discharged by the charging electrode, and the droplet is charged with a charge amount according to the recording signal. When the droplet of the recording liquid whose charge amount is controlled flies between the deflection electrodes to which a constant electric field is uniformly applied, the droplet is deflected according to the added charge amount and carries a recording signal. Only the recording material can be deposited on the recording member.

The third method is, for example, a method (Hertz method) disclosed in US Pat. No. 3,416,153, in which an electric field is applied between a nozzle and a ring-shaped charging electrode, and a small amount of recording liquid is applied by a continuous vibration generation method. In this method, droplets are generated and atomized and recorded. That is, in this method, the atomization state of the small droplet is controlled by modulating the electric field intensity applied between the nozzle and the charging electrode in accordance with the recording signal, and the image is recorded with the gradation of the recorded image.

The fourth system is, for example, a system (Stemme system) disclosed in US Pat. No. 3,747,120, and this system is fundamentally different from the above three systems in principle.

That is, in each of the three methods, the droplet of the recording liquid discharged from the nozzle is electrically controlled during the flight, and the droplet carrying the recording signal is selectively attached to the recording member. On the other hand, according to the Stemme method, recording is performed by ejecting a small droplet of recording liquid from an ejection port in accordance with a recording signal.

That is, in the Stemme method, the piezoelectric vibrating element attached to the recording head having the ejection port for ejecting the recording liquid includes:
Applying an electrical recording signal, converting the electrical recording signal into mechanical vibration of a piezo-vibrating element, and ejecting a droplet of the recording liquid from the ejection port in accordance with the mechanical vibration to cause the droplet to fly and adhere to the recording member. Is to record.

Each of these four conventional methods has its own features, but on the other hand, there are points that can be solved.

That is, in the first to third methods, the direct energy of the generation of the droplet of the recording liquid is electric energy,
Droplet deflection control is also electric field control. Therefore, the first method is simple in structure, but requires a high voltage to generate small droplets, and is not suitable for high-speed printing because it is difficult to use a multi-nozzle recording head.

The second method enables multi-nozzle recording heads and is suitable for high-speed recording. However, the method is complicated in structure, and the electrical control of small droplets of recording liquid is difficult and difficult. Are liable to occur.

The third method has a feature that an image having excellent gradation can be recorded by atomizing a recording liquid droplet, but on the other hand, it is difficult to control the atomization state, and fogging occurs in the recorded image. In addition, there are problems such as the fact that it is difficult to use a multi-nozzle recording head, and it is not suitable for high-speed recording.

The fourth scheme has relatively many advantages over the first to third schemes. That is, in order to perform recording by discharging the recording liquid from the discharge port of the nozzle on demand (on-demand), the configuration is simple. It is unnecessary to collect small droplets that are not required for recording an image, and there is no need to use a conductive recording liquid as in the first and second methods, and the recording liquid material There are great advantages such as a large degree of freedom. However, on the other hand, it is difficult to form a multi-nozzle recording head because there are problems in processing the recording head and it is extremely difficult to reduce the size of the piezoelectric vibrating element having a desired resonance number. However, since the recording liquid droplets are ejected and fly by the mechanical energy of mechanical vibration of the piezo-vibration element, it is not suitable for high-speed recording.

As described above, the conventional method has advantages and disadvantages in terms of configuration, high-speed recording, multi-nozzle recording head, generation of satellite dots and occurrence of fogging of a recorded image, etc. There was a restriction that only the application was possible.

Japanese Patent Application Laid-Open No. 55-128468 discloses that the specific resistance is 5 × 10
It is disclosed that a heating element is protected by a thin film of ⁵ Ω · cm or more.

FIG. 7 is a view for explaining an example of the liquid jet recording head disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 55-128468. A heating element 2 is provided on the surface of a heating element installation substrate 1. or,
As a material of the substrate 3, glass, ceramics, heat-resistant plastic, or the like is used. On the substrate 3, a chamber 4 'for accommodating ink before ejection and a long groove 4 constituting an ejection orifice 5 are formed beforehand. After aligning
Joined and integrated with an adhesive.

FIG. 8 is a sectional view taken along the axis of the groove 4, and the recording ink is supplied into the chamber 4 'as shown by the arrow in the figure. Now, when a signal is externally applied to the heat generating portion 2 attached to one part in the chamber 4 ', the heat generating portion 2 generates heat and gives heat energy to ink in the vicinity thereof. The ink that has received the thermal energy causes a state change such as volume expansion or bubble generation to generate a pressure change. This pressure change is transmitted in the direction of the discharge orifice 5, and the ink is discharged as small droplets. Then, recording is performed by the small droplets adhering to an arbitrary recording material such as paper (not shown).

FIG. 8 shows a detailed structure of the heating element installation board 1. The heating section 2 has a heat storage layer 7, a heating resistor 10, and an electrode 8 formed on a substrate 6 made of alumina or the like in the order of thin films. After laminating by a technique and patterning the heating resistor 10 and the electrode 8 into a predetermined shape, the protective layer 9 is further laminated. Then, the heat generating portion 2 is configured to discharge into the groove 4. In the heating element installation substrate 1, it is the protection layer 9 that the ink is directly applied to.
The electrode 10 and the electrode 8 are in contact with the ink and are oxidized, and on the contrary, they are insulated to prevent the ink from being electrolyzed. Specifically, the protective layer 9 has a specific resistance of 5 × 10 ⁵ Ω.・ C
A thin film having a thickness of about 0.1 μm to 5 μm which is not less than m is formed.

However, in the above-described liquid jet recording head, when the protection of the heating element portion is considered, the specific resistance of the thin film is one of the important factors, but more specifically, it is discussed in relation to the heating resistor layer. There must be.

Further, JP-A-59-143650 discloses that the surface of an electrode is altered to form a protective layer made of an inorganic insulating material.

9 and 10 are views for explaining an example of the liquid jet recording head disclosed in the above-mentioned JP-A-59-143650. FIG. 9 is a partial front view seen from the orifice side. No.
FIG. 10 is a partial cross-sectional view taken along the line indicated by the dashed line AA ′ in FIG. 9, and the liquid jet recording head shown in FIG. A substrate 12 for liquid jet recording (thermal ink jet: abbreviated as T / J) that uses the provided heat for liquid ejection, and a groove having a desired number of grooves provided corresponding to the electrothermal transducer 11 Board 13
And the main part is constituted.

The T / J substrate 12 and the grooved plate 13 are joined to each other with an adhesive or the like at a predetermined location, so that the portion of the T / J substrate 12 where the electrothermal converter 11 is provided, and the groove of the grooved plate 13 Part and the liquid flow path 14
The liquid flow path 14 has a heat acting part 15 in a part of its configuration.

The T / J substrate 12 has a support 16 made of silicon, glass, ceramics, or the like, a lower layer 17 made of SiO ₂ or the like on the support 16, a heating resistance layer 18, and the like. Tier 18
On both sides of the surface of the electrode 19, there are portions along the liquid flow path 14 that are not covered with the electrodes 19, 20 and the electrodes of the heating resistance layer 18, and the electrodes 19, 20.
And a protective layer (upper layer) 21 made of an inorganic material so as to cover the above portion.

The electrothermal converter 11 has a heat generating part 22 as a main part thereof, and the heat generating part 22 includes a lower layer 17, a heating resistor layer 18, and an upper layer part 21 on a support 16 sequentially from the support 16 side. The surface (thermally acting surface) 23 of the upper layer 21 is
It is in direct contact with the filling liquid. In the case of the liquid jet recording head shown in the figure, the upper layer 21 has a double-layer structure in which layers 26 and 27 are provided in order to further increase the mechanical strength of the layer 21. For example, inorganic oxides such as SiO ₂ and Si ₃ N
_The layer 27 is made of an inorganic material having relatively excellent electrical insulation, thermal conductivity, and heat resistance, such as inorganic nitrides such as ₄ , and the layer 27 is sticky and has relatively excellent mechanical strength. For example, when the layer 26 is formed of SiO ₂
It is composed of a metal material such as Ta.

Since the surface layer of the upper layer 21 is made of a relatively sticky and mechanically strong inorganic material such as a metal in this way, the cavitation effect generated at the time of liquid ejection on the heat acting surface 23 is reduced. Shock can be sufficiently absorbed, and there is an effect that the life of the electrothermal converter 11 is significantly extended.
The liquid jet recording head, characterized in that a protective layer 24 made of an inorganic insulating material is provided on the surface of the electrodes 19 and 20 by altering the surface of the electrode.
Although not shown, at least on the bottom surface of the common liquid chamber provided on the extension of the electrode 20 and upstream of the liquid flow path 14.

The protective layer 24 is provided on the surface of the electrode portion, and its main functions are to prevent liquid penetration and to act as a liquid. Further, by providing the electrode wiring portion behind the common liquid chamber so as to cover the electrode wiring portion, it is possible to prevent the electrode wiring portion from being scratched during the manufacturing process and from being disconnected. .

As described above, in the liquid jet recording head, in order to protect the electrodes, the relationship between the electrodes and the volume resistivity of the protective layer is important. However, Japanese Patent Application Laid-Open No.
JP-143650-A only describes "inorganic insulating material" but does not specifically describe how much insulation should be achieved. Further, the insulation is not a problem of the protective layer alone, but must be defined in relation to the electrodes.

Furthermore, in JP-A-55-128468, the heater size is 200 μm × 40 μm, and in JP-A-59-143650, the heater size is relatively large, such as 150 μm × 30 μm. For example, if the heater pattern width is 25μm or less,
For a head having a very fine heater pattern, which has a problem in production yield or durability when used for a long period of time, JP-A-55-128468 or JP-A-59-143650 is merely used. Good results were not always obtained with only the technology disclosed in the gazette.

This is disclosed in JP-A-55-128468 or JP-A-59-128468.
As described in Japanese Patent Application Laid-Open No. 143650, a problem that was not a problem with a relatively large heater pattern (or an electrode pattern) (a pattern caused by minute defects or particles of a material such as a heating element layer, an electrode layer, and a protective layer). Defects etc.)
Also, because the pattern width is fine, due to the manufacturing process,
Or, it has become a problem in design. In addition, in the case of a head that is driven continuously at a very high speed (eg, higher than 5 KHz), the number of heat cycles is very large. (Corrosion due to ink, etc.), and its protection means must be more strictly studied than in the case where the response frequency of the repetition is not so fast.

Object The present invention has been made in view of the above circumstances, and particularly has a fine heater size and a fine electrode pattern, is arranged at a very high density (for example, 16 lines / mm or more), and High-speed drive (continuous drive response frequency
The purpose of the present invention is to provide a bubble jet type liquid jet recording apparatus operated at a speed higher than 5 KHz) for the purpose of (1) protecting the heat generating portion and (2) improving the durability of the electrode portion.

Configuration The present invention provides: (1) a flow path provided with a thermal energy action section for containing a recording liquid to be introduced, generating bubbles in the recording liquid by heat, and generating an action force accompanying an increase in the volume of the bubbles. An orifice for communicating with the flow path to discharge the recording liquid as droplets by the action force, and a liquid chamber for communicating with the flow path and introducing the recording liquid into the flow path; In a liquid jet recording head comprising means for introducing the recording liquid into a liquid chamber, the liquid jet recording head is driven at a continuous drive response frequency higher than 5 KHz, and the heat energy action section includes a heating resistor layer, At least one pair of electrodes electrically connected to the heating resistor layer, and a protective layer provided on the heating resistor layer for preventing the heating resistor layer from contacting the recording liquid, Departure When the pattern width of the resistor and the pattern width of the electrode connected to the resistor are a fine pattern of 25 μm or less at the connection portion, the thickness of the protective layer is set to be about three times or more the thickness of the heating resistance layer, The volume resistivity of the heating resistor layer is ρh, and the volume resistivity of the protective layer is ρhi.
When And (2) accommodating the recording liquid to be introduced and generating bubbles in the recording liquid by heat, thereby generating an action force accompanying an increase in the volume of the bubbles. A flow path provided with a thermal energy action section to be applied, an orifice for communicating with the flow path to discharge the recording liquid as droplets by the acting force, and a recording medium for communicating with the flow path in the flow path. In a liquid chamber for introducing a liquid, and a liquid jet recording head comprising means for introducing the recording liquid into the liquid chamber, the liquid jet recording head is driven at a continuous drive response frequency higher than 5 KHZ, The heat energy action section is provided so as to cover the heating resistor layer, at least a pair of electrodes electrically connected to the heating resistor layer, and the electrode, and to contact the electrode with the recording liquid. An electrode protection layer for preventing squeezing, and when the pattern width of the heating resistor and the pattern width of an electrode connected to the heating resistor are a fine pattern of 25 μm or less in the vicinity of the connection portion, the electrode protection layer is made of an inorganic material. In the case of, the thickness is equal to or greater than the thickness of the electrode,
In the case of an organic substance, when the thickness is set to approximately twice or more the thickness of the electrode, and the volume resistivity of the electrode is ρe, and the volume resistivity of the electrode protection layer is ρei, And (3) accommodating the recording liquid to be introduced and generating bubbles in the recording liquid by heat, thereby generating an action force associated with an increase in the volume of the bubbles. A flow path provided with a thermal energy action section to be applied, an orifice for communicating with the flow path to discharge the recording liquid as droplets by the acting force, and a recording medium for communicating with the flow path in the flow path. In a liquid jet recording head comprising a liquid chamber for introducing a liquid and a means for introducing the recording liquid into the liquid chamber, the liquid jet recording head is driven at a continuous drive response frequency higher than 5 KHz, and the thermal energy The action section includes a heating resistor layer, at least one pair of electrodes electrically connected to the heating resistor layer, and a contact portion provided on the heating resistor layer to contact the heating resistor layer with the recording liquid. A protective layer for preventing squeezing, and an electrode protective layer provided so as to cover the electrode and prevent the electrode from contacting the recording liquid, and the width of the pattern of the heating resistor and the electrode connected thereto. When the pattern width is a fine pattern of 25 μm or less in the vicinity of the connection portion, the thickness of the protective layer is set to be approximately three times or more the thickness of the heating resistor layer, and the volume resistance of the heating resistor layer is increased. When the resistivity is ρh and the volume resistivity of the protective layer is ρhi, Constituting the thermal energy acting portion by a material to be,
When the electrode protective layer is an inorganic material, its thickness is equal to or greater than the thickness of the electrode, and when it is an organic material, the thickness is approximately twice or more the thickness of the electrode, and the volume resistivity of the electrode is Is ρe, and the volume resistivity of the electrode protection layer is ρei, The electrode portion is made of a material to be described below. Hereinafter, a description will be given based on examples of the present invention.

FIG. 1 is a main part configuration diagram for explaining an example of the above-mentioned object (1), that is, an example of a liquid jet recording head for improving the durability of the heating element portion, and FIG. 3) That is, a main part configuration diagram of a liquid jet recording head for improving the durability of an electrode, and FIG. 3 is a diagram for explaining the operation of a bubble jet head as an example of an ink jet head to which the present invention is applied. FIG. 4 is a perspective view showing an example of a bubble jet head, and FIG. 5 is a lid substrate constituting the head shown in FIG. 4 (FIG. 5 (a)).
And a perspective view when disassembled into a heating element substrate (FIG. 5 (b)).
FIG. 6 is a perspective view of the lid substrate shown in FIG. 5 (a) as viewed from the back side, in which 31 is a lid substrate, 32 is a heating element substrate, 33 is a recording liquid inlet, 34 is an orifice, 35 is a flow path, 36 is a region for forming a liquid chamber, 37 is an individual (independent) electrode, 38 is a common electrode, 39 is a heating element (heater), 40 is ink, 41 is a bubble,
Reference numeral 42 denotes a flying ink droplet, and the present invention is applied to such a bubble jet type liquid jet recording head.

First, the ink ejection by the bubble jet will be described with reference to FIG. 3. (a) is a steady state, in which the surface tension of the ink 40 and the external pressure are in an equilibrium state at the orifice surface.

6B, the heater 39 is heated until the surface temperature of the heater 39 sharply rises and the adjacent ink layer is heated until boiling development occurs, and the micro bubbles 41 are scattered.

FIG. 3C shows a state in which the adjacent ink layer heated rapidly on the entire surface of the heater 39 is instantaneously vaporized to form a boiling film, and the bubbles 41 grow. At this time, the pressure in the nozzle rises by an amount corresponding to the growth of the bubble, the balance with the external pressure on the orifice surface is lost, and the ink column starts to grow from the orifice.

(D) is a state in which the bubble has grown to the maximum, and the ink 40 corresponding to the volume of the bubble is pushed out from the orifice surface. At this time, no current is flowing through the heater 39, and the surface temperature of the heater 39 is decreasing. The maximum value of the volume of the bubble 41 is slightly delayed from the timing of applying the electric pulse.

(E) shows a state in which the bubble 41 has been cooled by ink or the like and has begun to contract. At the front end of the ink column, the ink moves forward while maintaining the pushed speed, and at the rear end, the ink flows backward from the orifice surface into the nozzle due to a decrease in the nozzle internal pressure due to the contraction of the bubble, and the ink column is constricted. .

4F, the bubble 41 is further contracted, the ink comes into contact with the heater surface, and the heater surface is cooled more rapidly. At the orifice surface, the external pressure is higher than the internal pressure of the nozzle, so that the meniscus largely enters the nozzle. The tip of the ink column becomes a droplet and moves in the direction of the recording paper.
Flying at a speed of 10m / sec.

(G) is a process in which the ink is again supplied (refilled) to the orifice by capillary development and returns to the state of (a).
The bubbles have completely disappeared.

Thus, in the embodiment shown in FIG. 1, reference numeral 43 denotes a heat storage layer, reference numeral 44 denotes a heating resistor protection layer, reference numeral 45 denotes an electrode protection layer. The drawing is a cross-sectional view of a heat energy action section. As shown in the figure, a heating resistor layer 39 heats a recording liquid (ink) 40 via a protective layer 44. . In this part, the generation, shrinkage, and disappearance of bubbles are repeated, and the heat cycle is constantly repeated. In addition, this repetition is repeated more than 5,000 times per second at a maximum, and the impact due to the cavitation action of the heat cycle or the disappearance of bubbles is concentrated in a very fine region, that is, a region of 25 μm or less in the pattern width. So
In terms of durability, they are in very harsh conditions. In addition, because of the extremely severe conditions that the surroundings are a recording liquid having a corrosive action, dielectric breakdown in this portion is one of the most important issues for bubble jet technology. In order to solve this, it is not necessary to simply determine the specific resistance of the protective layer 44, but it is necessary to suppress the relationship with the heating resistor layer 39 that receives a pulse signal and generates heat. The present inventor has determined that the heating resistor layer 39 and the protective layer 44
Prototype of a bubble jet type liquid jet recording head with different volume resistivity (this can change the material itself, or change the film quality of each layer by changing the production conditions). When a test was conducted to achieve a configuration satisfying the following relationship, the durability of the heating element (thermal energy action section) of the recording head was improved, and its life was extended.
We found that we could do more than 10 ⁹ pulses.

However, ρhi: the volume resistivity of the protective layer 44 ρh: the volume resistivity of the heating resistor layer 39 Examples of useful materials for forming the heating resistor layer 39 include tantalum nitride, nichrome, silver-palladium alloy, Silicon semiconductor or boride of metal such as hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium, vanadium and the like can be given. Among the materials constituting these heating resistor layers,
In particular, metal borides can be mentioned as excellent,
Among them, hafnium boride has the best characteristics, followed by zirconium boride, tantalum boride, lanthanum boride, vanadium boride, and niobium boride in that order.

The heating resistor layer can be formed using the above-mentioned materials by a technique such as electron beam evaporation or sputtering. The thickness of the heating resistor layer is determined according to its area, material, shape and size of the heat acting portion, and furthermore, the actual power consumption so that the amount of heat generated per unit time is as desired. Is usually 0.001 to 5 μm,
Preferably it is 0.01 to 1 μm.

Useful materials for forming the protective layer include, for example, silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, zirconium oxide, and the like, which are formed by using a technique such as electron beam evaporation or sputtering. Can be formed. The thickness of the protective layer is usually desirably 0.01 to 10 μm, preferably 0.1 to 3 μm.

As a material for forming the electrode, many of the commonly used electrode materials are effectively used, and specifically, for example, Al, Ag, Au, Pt, Cu, etc., are used. It is provided at a predetermined position in a predetermined size, shape and thickness by a technique such as vapor deposition.

The embodiment shown in FIG. 2 is intended to improve the durability of the electrode portions 37 and 38 in contact with the recording liquid (ink) against dielectric breakdown. FIG. 2 is an enlarged view of the heating element substrate. The hatched portion 46 in the figure is an electrode protection layer. In addition,
The pattern of the electrode protection layer is an example, and may be formed independently for each electrode instead of covering the entire surface as illustrated. The electrode protection layer is provided to prevent the electrodes from contacting the recording liquid (ink). The condition that not only the electrode protective layer itself is in contact with the recording liquid but also that the heating resistor layer (thermal energy action part) in the vicinity repeats the heat cycle more than 5,000 times per second. It is in a very difficult situation. In addition, since the heat cycle, the corrosive action by ink, and the action of dielectric breakdown are added to a very fine area with an electrode pattern width of 25 μm or less, it is exposed to extremely severe conditions in terms of durability. It can be said that. It is the role of the electrode protection layer to protect the electrode from dielectric breakdown under such conditions. Therefore, when forming the electrode protection layer, it is necessary to determine not only the material itself but also the relationship with the electrode material. The present inventor has changed the volume resistivity of each of the electrode and the electrode protective layer (this can change the material itself, or can change the film conditions of each layer by changing the production conditions). An ejection recording head was prototyped and subjected to an ejection durability test, and it was found that dielectric breakdown of the electrode was unlikely to occur when the structure was such that the following relationship was satisfied.

However, ρei: the volume resistivity of the heat generation protection layer ρe: the volume resistivity of the electrode As the material constituting the electrode, many of the commonly used electrode materials are effectively used. As in the case of the embodiment shown in the figure, Al, Ag, Au, Pt, Cu, etc. are used, and they are provided at a predetermined position, in a predetermined size, shape, and thickness by a method such as vapor deposition using these. Can be

As a material constituting the electrode protection layer, for example, an organic epoxy resin, a Teflon resin, a polyethylene resin, or the like is used. In the case of an inorganic substance, silicon oxide, nitrogen silicon, or the like can be formed by a technique such as sputtering.

As a material constituting the other members, for example, useful as a material constituting the heating resistor layer include nitrogen tantalum, nichrome, silver-palladium alloy, silicon semiconductor, or hafnium, lanthanum, zirconium, titanium, tantalum, Tungsten, molybdenum, niobium,
Borides of metals such as chromium and vanadium can be mentioned. Among these materials constituting the heating resistor layer, metal borides can be mentioned as being particularly excellent. Among them, hafnium boride has the most excellent properties, and zirconium boride is second. , Lanthanum boride, tantalum boride,
The order is vanadium boride and niobium boride.

The heating resistor layer can be formed using the above-mentioned materials by a technique such as electron beam evaporation or sputtering. The film layer of the heating resistor layer is determined according to its area, material, shape and size of the heat acting portion, and furthermore, power consumption in the actual plane, so that the amount of heat generated per unit time is as desired. , But usually 0.001-5μ
m, preferably 0.01 to 1 μm.

Useful materials for forming the protective layer include, for example, silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, zirconium oxide, and the like, which are formed by using a technique such as electron beam evaporation or sputtering. Can be formed. The thickness of the protective layer is usually desirably 0.01 to 10 μm, preferably 0.1 to 3 μm.

Results are continuously driven in Examples 1 and 2 both 5.4 kHz, and function normally without being broken even when driven over ¹⁰⁹ times.

Results As is apparent from the above description, according to the present invention, in the bubble jet type liquid jet recording head, the durability of the heating element portion is remarkably improved, the dielectric breakdown of the electrodes is hardly caused, and the durability is improved. Can be significantly improved.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are each a main part configuration diagram for explaining an embodiment of the present invention, and FIGS. 3 to 6 are diagrams for explaining an example of a liquid jet recording head to which the present invention is applied. 7 to 10 are views for explaining an example of a conventional liquid jet recording head. 32 Heating element substrate, 37, 38 Electrodes, 39 Heating element, 44
... Heating element protection layer, 45 ... Electrode protection layer.

Claims (3)

(57) [Claims] A flow path provided with a thermal energy action portion for containing a recording liquid to be introduced, generating bubbles by heat in the recording liquid, and generating an action force accompanying an increase in the volume of the bubbles; An orifice for communicating with a path to discharge the recording liquid as droplets by the action, a liquid chamber for communicating with the flow path and introducing the recording liquid into the flow path, and In a liquid jet recording head comprising means for introducing a recording liquid, the liquid jet recording head is driven at a continuous drive frequency higher than 5 KHz, and the heat energy action section includes a heating resistor layer and the heating resistor layer. And a protection layer provided on the heating resistor layer for preventing the heating resistor layer from contacting the recording liquid. When the pattern width of the electrode and the pattern width of the electrode connected thereto is a fine pattern of 25 μm or less at the connection portion, the thickness of the protective layer is set to be about three times or more the thickness of the heating resistor layer, When the volume resistivity of the heating resistor layer is ρh and the volume resistivity of the protective layer is ρhi, A liquid jet recording head, wherein the thermal energy action section is made of a material to be used. 2. A flow path provided with a thermal energy action portion for containing a recording liquid to be introduced, generating bubbles by heat in the recording liquid, and generating an action force accompanying an increase in the volume of the bubbles. An orifice for communicating with a path to discharge the recording liquid as droplets by the action force; a liquid chamber for communicating with the flow path and introducing the recording liquid into the flow path; In the liquid jet recording head comprising the means for introducing the recording liquid, the liquid jet recording head is driven at a continuous drive frequency higher than 5 KHz, and the heat energy action section includes a heating resistor layer and the heating resistor. A pattern of the heating resistor, comprising at least a pair of electrodes electrically connected to the body layer, and an electrode protection layer provided over the electrodes to prevent the electrodes from contacting the recording liquid; When the width of the electrode and the pattern width of the electrode connected to it are a fine pattern of 25 μm or less in the vicinity of the connection portion, when the electrode protective layer is an inorganic material, the thickness is equal to or greater than the thickness of the electrode, In the case of an organic substance, when the thickness is set to be approximately twice or more the thickness of the electrode, the volume resistivity of the electrode is ρe, and the volume resistivity of the electrode protection layer is ρei, A liquid jet recording head, wherein the electrode portion is made of a material to be used. 3. A flow path provided with a thermal energy action portion for containing a recording liquid to be introduced, generating bubbles by heat in the recording liquid, and generating an action force accompanying an increase in the volume of the bubbles. An orifice for communicating with a path to discharge the recording liquid as droplets by the action force; a liquid chamber for communicating with the flow path and introducing the recording liquid into the flow path; In the liquid jet recording head comprising the means for introducing the recording liquid, the liquid jet recording head is driven at a continuous drive frequency higher than 5 KHz, and the heat energy action section includes a heating resistor layer and the heating resistor. At least a pair of electrodes electrically connected to the layer, a protective layer provided on the heating resistor layer for preventing the heating resistor layer from contacting the recording liquid, and a protective layer covering the electrodes. An electrode protection layer for preventing the electrode from being brought into contact with the recording liquid, wherein the pattern width of the heating resistor and the pattern width of the electrode connected thereto are smaller than 25 μm in the vicinity of the connection portion. In the case of a pattern, the thickness of the protective layer is approximately three times or more the thickness of the heating resistor layer, the volume resistivity of the heating resistor layer is ρh, and the volume resistivity of the protection layer is ρhi. and when, Constituting the thermal energy acting portion by a material to be,
When the electrode protective layer is made of an inorganic material, its thickness is made equal to or more than the thickness of the electrode, and when made of an organic material, its thickness is made almost twice or more the thickness of the electrode, and the volume resistivity of the electrode is made. Is ρe, and the volume resistivity of the electrode protection layer is ρei, A liquid jet recording head, wherein the electrode portion is made of a material to be used.