JPH01196352A - Liquid jet-recording head - Google Patents

Abstract

PURPOSE:To improve the durability of a heat generating part by making a specific relationship between the volume resistivity of a thermal resistor layer in a thermal energy action part and the volume resistivity of a protection layer provided on the thermal resistor layer. CONSTITUTION:The thermal resistor layer 39 of a thermal energy action part heats recording liquid 40 through a protection layer 44. At that time, if the volume resistivity of the thermal resistor layer 39 is taken to be rhoh and the volume resistivity of the protection layer 44 is taken to be rhohi, the relationship of the formula I should be satisfied. In addition, in order to improve the durability of electrode parts 37, 38 which come into contact with the recording liquid against the insulation breakdown of the electrode parts, an electrode protection part is provided. At that time, if the volume resistivity of the electrodes 37, 38 is taken to be rhoe and the volume resistivity of the electrode protection layer 46 is taken to be rhoei, the relationship of the formula II should be satisfied. The preferable materials used for the thermal resistor layer 39 are hafnium boride, zirconium boride, etc. The recommendable materials used for the protection layer 44 are aluminium oxide, zirconium oxide, etc. and those for the electrode protection layers 37, 38 are organic polyethylene resin, etc. as well as inorganic silicon oxide, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid jet recording head, and more particularly to protection of a heat generating part or an electrode part of a bubble jet type ink jet head.

The non-impact recording method of Asahimai sailing has recently attracted attention because the noise generated during recording is so small that it can be ignored. Among them, high-speed recording is possible,
However, the so-called inkjet recording method, which allows recording on plain paper without the need for special fixing treatment, is an extremely powerful recording method, and various methods have been proposed and improvements have been made to improve the quality of products. Some have been developed, and efforts are still being made to put them into practical use.

Such an inkjet recording method involves jetting droplets of a recording liquid called ink.

Recording is performed by attaching the recording liquid to a recording member, and it is roughly divided into several methods depending on the method of generating recording liquid droplets and the control method for controlling the flight direction of the generated recording liquid droplets. Ru.

First, the first method is the one disclosed in, for example, USP 3060429 (Tels type method), in which droplets of recording liquid are generated by electrostatic absorption, and the generated recording liquid droplets are used as a recording signal. Recording is performed by controlling the electric field in accordance with the temperature and selectively depositing recording liquid droplets on the recording member.

To explain this in more detail, an electric field is applied between the nozzle and the accelerating electrode to eject a negatively charged recording liquid droplet from the nozzle, and the ejected recording liquid droplet is converted into a recording signal. Accordingly, the droplet is caused to fly between x and y deflection electrodes configured to be electrically controllable, and the droplet is selectively deposited on the recording member by changing the intensity of the electric field to perform recording.

The second method is described, for example, in USP 3596275, U
The method disclosed in SP 3298030 etc. (Swe
et method), in which droplets of recording liquid with a controlled amount of charge are generated by a continuous vibration generation method, and a --like electric field is applied to the generated droplets with a controlled amount of charge. Recording is performed on a recording member by flying between deflection electrodes.

Specifically, the orifice (discharge port) of a nozzle, which is a part of the recording head to which the piezo vibrating element is attached.
A charged electrode configured to have a recording signal applied thereto is arranged at a predetermined distance in front of the piezo vibrating element, and an electric signal of a constant frequency is applied to the piezo vibrating element to mechanically vibrate the piezo vibrating element, A small droplet of recording liquid is ejected from the ejection port. At this time, charges are electrostatically induced in the recording liquid droplet discharged by the charging electrode, and the droplet is charged with an amount of charge corresponding to the recording signal. When a droplet of recording liquid with a controlled amount of charge flies between deflection electrodes to which a constant electric field is uniformly applied, it is deflected according to the amount of charge applied.
Only the droplets carrying the recording signal are allowed to deposit on the recording member.

The third method is a method (Hertz method) disclosed, for example, in U.S. Pat. This is a method of converting and recording. That is, in this method, the atomization state of droplets is controlled by modulating the electric field intensity applied between the nozzle and the charging electrode in accordance with the recording signal, and the gradation of the recorded image is produced.

The fourth method is, for example, the method disclosed in USP 3747120 (Stemme method), and this method is fundamentally different in principle from the above three methods.

That is, in all three methods, the droplets of recording liquid ejected from the nozzle are electrically controlled while they are in flight, and the droplets carrying the recording signal are selectively attached to the recording member. In contrast, this Steam method
Recording is performed by ejecting small droplets of recording liquid from an ejection port in response to a recording signal.

In other words, in the Ste+mme method, an electrical recording signal is applied to a piezo vibrating element attached to a recording head that has an ejection port for discharging recording liquid, and this electrical recording signal is applied to the mechanical vibration of the piezo vibrating element. In this method, recording is performed by ejecting small droplets of recording liquid from the ejection opening according to the mechanical vibrations and adhering them to the recording member.

These four conventional methods each have their own advantages, but there are also points that can be solved in the other method.

That is, in the first to third methods, the direct energy for generating droplets of the recording liquid is electrical energy, and the deflection control of the droplets is also electric field control.

Therefore, although the first method is simple in structure, it requires a high voltage to generate droplets, and it is difficult to use a multi-nozzle recording head, making it unsuitable for high-speed recording.

The second method allows the recording head to have multiple nozzles and is suitable for high-speed recording, but it has a complicated structure, and the electrical control of recording liquid droplets is sophisticated and difficult, and satellite dots are placed on the recording member. There are problems such as easy occurrence of. - The third method has the advantage of being able to record images with excellent gradation by atomizing small droplets of recording liquid, but on the other hand, it is difficult to control the atomization state and fogging may occur in the recorded image. It is difficult to create a multi-nozzle recording head.
There are various problems such as being unsuitable for high-speed recording.

The fourth method has relatively many advantages compared to the first to third methods. In other words, the structure is simple, and since recording is performed by ejecting recording liquid from the ejection opening of the nozzle on-demand, it is possible to reduce the number of small droplets that fly as in the first to third methods. Second, it is not necessary to collect droplets that are not needed to record an image, and unlike the first and second methods, there is no need to use a conductive recording liquid, and the material of the recording liquid is It has great advantages such as a high degree of freedom. On the other hand, it is difficult to make the recording head multi-nozzle because there are problems in processing the recording head, and it is extremely difficult to miniaturize the piezoelectric vibrating element having the desired resonance number. This method has drawbacks such as that it is not suitable for high-speed recording because the recording liquid droplets are ejected and ejected in flight using the mechanical energy of the mechanical vibration of the piezoelectric vibrating element.

Furthermore, Japanese Patent Application Laid-Open No. 48-9622 (the above-mentioned USP
No. 3,747,120) describes, as a modification, the use of thermal energy instead of the mechanical vibration energy provided by means such as the piezo vibration element.

That is, the above-mentioned publication describes a so-called bubble jet liquid jet recording device that uses a heating coil that directly heats liquid as a pressure increasing means instead of a piezo vibrating element to generate steam that causes a pressure increase. There is.

However, in the above publication, the liquid ink in the bag-shaped ink chamber (liquid chamber), which has only one opening through which liquid ink can go in and out, is directly heated and vaporized by energizing the heating coil as a pressure increasing means. However, when discharging liquid continuously and repeatedly, it is not clear how to heat it.
In addition, the heating coil is located at the deepest part of the bag-shaped liquid chamber far from the liquid ink supply path, so the head structure is complicated. In addition, it is not suitable for continuous, repeated use at high speeds.

Moreover, with the technical content described in the above-mentioned publication, it is not possible to quickly prepare for the next liquid discharge after discharging the liquid using the generated heat, which is important in practice.

As described above, conventional methods have advantages and disadvantages in terms of structure, high-speed recording, multi-nozzle recording heads, generation of satellite dots, and fogging of recorded images. There was a restriction that it could only be applied.

Further, Japanese Patent Application Laid-open No. 128468/1983 discloses that a heating element is protected by a thin film having a specific resistance of 5 x 10' ohms or more.

FIG. 7 is a diagram for explaining an example of the liquid jet recording head disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 55-128468, in which a heat generating portion 2 is provided on the surface of a heat generating body installation substrate 1. Further, as the material of the substrate 3, glass, ceramics, heat-resistant plastic, etc. are 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 in advance. After alignment, they are joined and integrated with 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 indicated by the arrow in the figure. Now, when a signal is applied from the outside to the heat generating part 2 attached to a part of the chamber 4', the heat generating part 2 generates heat and gives thermal energy to the ink in the vicinity thereof. The ink that has received thermal energy undergoes a change in state such as volumetric expansion or generation of bubbles, resulting in a pressure change, and this pressure change is transmitted in the direction of the ejection orifice 5, and the ink is ejected in the form of small droplets. Then, recording is performed by attaching these droplets to an arbitrary recording material such as paper (not shown).

FIG. 8 shows the detailed structure of the heating element installation board 1, and the heating unit 2 is made by sequentially forming a heat storage layer 7, a heating resistor 10, and an electrode 8 as a thin film on a substrate 6 made of alumina or the like. After the heating resistor 10 and the electrode 8 are laminated using a technique and patterned into a predetermined shape, a protective layer 9 is further laminated. The heat generating portion 2 is configured to discharge heat into the groove 4. In the heating element installation board 1, the protective layer 9 is in direct contact with the ink, but this protective layer 9 prevents the heating resistor 10 and the electrode 8 from coming into contact with the ink and being oxidized, or conversely insulating them. It prevents the ink from being electrolyzed, and specifically, the protective layer 9 has a specific resistance of 5
A thin film with a thickness of about 0.1 μm to 5 μm and a resistance of 10′Ω·■ or more is formed.

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

Furthermore, JP-A-59-143650 discloses altering the electrode surface to form a protective layer made of an inorganic insulating material.

Figures 9 and 10 are from the above-mentioned Japanese Patent Application Laid-Open No. 59-143650.
FIG. 9 is a partial front view as seen from the orifice side, and FIG. 10 is a diagram showing an example of the liquid jet recording head disclosed in the publication, and FIG. A partial cross-sectional view is shown in which the liquid jet recording head shown in the figure is a liquid jet recording head that is provided with a desired number of electrothermal converters 11 and utilizes heat for liquid ejection.
The main parts thereof include a substrate 12 for thermal inkjet (abbreviated as T/J) and a grooved plate 13 having a desired number of grooves provided corresponding to the electrothermal transducers 11.

The T/J board 12 and the grooved plate 13 are joined at predetermined locations with an adhesive or the like, so that the electrothermal converter 11 of the T/J board 12
The portion where the grooved plate 13 is provided and the groove portion of the grooved plate 13 form a liquid flow path 14, and the liquid flow path 14 has a heat acting portion 15 as a part of its structure.

The T/J board 12 includes a support 16 made of silicon, glass, ceramics, etc., and a 5i0
The heating resistor layer 18 has a lower layer 17, a heat generating resistor layer 18, etc., and both sides of the surface of the heat generating resistor layer 18 are covered with electrodes 19, 20 and the electrodes of the heat generating resistor layer 18 along the liquid flow path 14. A protective layer (upper layer) 21 made of an inorganic material is provided so as to cover the exposed portions and the electrode portions 19 and 20.

The electrothermal converter 11 has a heat generating section 22 as its main part, and the heat generating section 22 has a lower layer 17, a heating resistance layer 18, and an upper layer 21 formed on the support 16 in this order from the support 16 side. The upper layer 21 has a layered structure, and the surface (thermal action surface) 23 of the upper layer 21 is in direct contact with the liquid filling the liquid flow path 14 . In the case of the liquid jet recording head shown in the figure, the upper layer 2
1 is a layer 2 in order to further increase the mechanical strength of the core layer 21.
It has a double layer structure with 6.27, and the layer 26 is
For example, inorganic oxides such as Sin and 5i1N.

The layer 27 is made of an inorganic material with relatively excellent electrical insulation, thermal conductivity, and heat resistance, such as inorganic nitrides such as For example, when the layer 26 is made of SiC2, it is made of a metal material such as Ta.

By constructing the surface layer of the upper layer 21 from an inorganic material such as metal that is relatively sticky and has mechanical strength, the heat-active surface 23 is protected from the cavitation effect that occurs when liquid is discharged. Shocks can be sufficiently absorbed and the life of the electrothermal converter 11 can be significantly extended. The liquid jet recording head has 5! on the surfaces of the electrodes 19 and 20. II: A protective layer 24 made of an insulating material is provided by changing the quality of the electrode surface, and although not shown, the protective layer 24 is provided on the liquid flow path 14 on the extension of the electrode 20. The common liquid chamber is also provided at least at the bottom portion of the common liquid chamber provided upstream of the liquid chamber.

The protective layer 24 is provided on the surface of the electrode portion, and its main role is to prevent liquid penetration and provide liquid resistance. Furthermore, by covering the electrode wiring part behind the common liquid chamber, it is possible to prevent the electrode wiring part from being scratched or disconnected during the manufacturing process. .

Therefore, in the liquid jet recording head, the above-mentioned
In order to protect the electrode, the relationship between the volume resistivity of the electrode and its protective layer is important. However, the above-mentioned JP-A-59-
Publication No. 143650 only mentions ``inorganic insulating material'' but does not specifically state how much insulation should be used.

Further, the insulation must be determined not only by the protective layer but also by the relationship with the electrode.

Purpose The present invention was made in view of the above-mentioned circumstances.
In particular, in a bubble jet type liquid jet recording device,
This was done to (1) protect the heat generating part and (2) improve the durability of the electrode part.

(1) In order to achieve the above object (1), in other words, in order to protect the heat generating part, the present invention accommodates the recording liquid introduced and generates bubbles in the recording liquid by heat. a flow path provided with a thermal energy acting portion that generates an action force as the body f of bubbles increases; an orifice connected to the flow path for ejecting the recording liquid as droplets by the action force; In a liquid jet recording head comprising a liquid chamber for communicating with a flow path and introducing the recording liquid into the flow path, and a means for introducing the recording liquid into the liquid chamber, the thermal energy application section includes a heating resistor. a layer, at least one pair of electrodes electrically connected to the heating resistor layer, and a protective layer provided on the heating resistor layer to prevent the heating resistor layer from coming into contact with the recording liquid. When the volume resistivity of the heating resistor layer is ρh and the volume resistivity of the protective layer is ρhi, the following relationship is satisfied. In other words, to achieve
In order to improve the durability of the electrode section, a thermal energy application section is attached that accommodates the recording liquid introduced, generates bubbles in the recording liquid by heat, and generates an acting force as the volume of the bubbles increases. a flow path, an orifice communicating with the flow path to cause the recording liquid to be ejected as droplets by the acting force, and a liquid chamber communicating with the flow path to introduce the recording liquid into the flow path. In a liquid jet recording head comprising means for introducing the recording liquid into the liquid chamber, the thermal energy applying section includes a heating resistor layer and at least one pair of electrodes electrically connected to the heating resistor layer. , an electrode protective layer provided to cover the electrode to prevent the electrode from coming into contact with the recording liquid,
When the volume resistivity of the electrode is ρe and the volume resistivity of the electrode protective layer is ρei, the following relationship is satisfied. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a configuration diagram of a main part for explaining an example of a liquid jet recording head designed to improve the durability of the heating element part (1), that is, the above objective (2), and FIG. )
In other words, FIG. 3 is a diagram illustrating the main part of a liquid jet recording head designed to improve the durability of the electrodes. 4 is a perspective view showing an example of a bubble jet head, and FIG. 5 shows a lid substrate (FIG. 5(a)) and a heating element substrate (FIG. (b)) Perspective view when disassembled, No. 6
The figure is a perspective view of the lid substrate shown in FIG. 5(a), seen from the back side. In the figure, 31 is the lid substrate, 32 is the heating element substrate, 33 is the recording liquid inlet, 34 is the orifice, and 35 is the Channel, 36
37 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), 4o is ink, 41 is a bubble, 42 is a flying ink droplet, and the present invention includes:
This invention is applied to such a bubble jet type liquid jet recording head.

First, ink ejection by a 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 equilibrium on the orifice surface.

In (b), the heater 39 is heated until the surface temperature of the heater 39 rises rapidly and boiling a development occurs in the adjacent ink layer, and microbubbles 41 are scattered.

(c) shows a state in which adjacent ink layers that are rapidly heated over the entire surface of the heater 39 are instantaneously vaporized to form a boiling film, and the bubbles 41 grow. At this time, the pressure inside the nozzle increases by the amount of bubble growth, and the balance with the external pressure on the orifice surface is lost, causing an ink column to begin to grow from the orifice.

(d) shows a state in which the bubbles have grown to their maximum, and ink 40 corresponding to the volume of the bubbles 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 electric pulse application.

(e) shows a state in which the bubbles 41 are cooled by ink or the like and begin to contract.The tip of the ink column moves forward while maintaining the extruded speed, and the rear end of the column moves forward as the bubbles contract. Due to a decrease in internal pressure, ink flows back into the nozzle from the lift surface, creating a constriction in the ink column.

In (f), the air bubbles 41 are further contracted, the ink comes into contact with the heater surface, and the heater surface is cooled even more rapidly. At the orifice surface, the external pressure is higher than the nozzle internal pressure, so the meniscus is largely moving into the nozzle. The tip of the ink column becomes a droplet and drops 5 to 1 droplets toward the recording paper.
It is flying at a speed of 0 m/see.

In (g), the air bubbles have completely disappeared in the process of refilling the orifice with ink by capillary action and returning to the state of (a).

In the embodiment shown in FIG. 1, 43 is a heat storage layer, 44 is a heating resistor protective layer, and 45 is an electrode protective layer, and this embodiment is designed to improve the durability against insulation damage of the heating element. This figure shows a cross-sectional view of the thermal energy acting part, and as shown, the heating resistor layer: 39
The recording liquid (ink) 40 is transferred through the storage layer 44.
heat up. In this part, bubbles are repeatedly generated, contracted, and disappeared, and the heat cycle is constantly repeated. Moreover, since the surroundings are recording liquid, which is a very severe condition, dielectric breakdown in this part is one of the most important issues for bubble jet technology. In order to solve this problem, it is not enough to simply determine the specific resistance of the protective layer 44, but it is also necessary to control the relationship with the heating resistor layer 39, which receives a pulse signal and generates heat.

The present inventor changed the volume resistivity of each of the heating resistor layer 39 and the protective layer 44 (this can be done by changing the material itself or
Alternatively, by changing the formation conditions, the film quality of each layer can be changed.) A bubble jet type liquid jet recording head was prototyped, a jetting durability test was conducted, and when the configuration satisfied the following relationship, the recording head It has been found that the durability of the heating element portion (thermal energy acting portion) of the device is improved, and its lifespan can be extended to 109 pulses or more.

However, ρhi: Volume resistivity of the protective layer 44 ρh: Volume resistivity of the heat generating resistor layer 39 Examples of materials useful for forming the heat generating resistor layer 39 include tantalum nitride, nichrome, silver-palladium alloy, Examples include silicon semiconductors and borides of metals such as hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium, and vanadium. Among the materials constituting these heating resistor layers, metal borides are particularly excellent, and among these, hafnium boride has the best properties, followed by zirconia boride. 11. The order is lanthanum boride, tantalum boride, vanadium boride, and niobium boride.

The heating resistor layer can be formed using the above-mentioned materials by techniques such as electron beam IX evaporation and sputtering. The thickness of the heating resistor layer is determined in accordance with its area, material, shape and size of the heat acting part, and actual power consumption, etc. so that the amount of heat generated per unit time is as desired. However, in normal cases, it is 0.001 to 5
μm, preferably 0.01 to 1 μm.

Examples of useful materials for forming the protective layer include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, and zirconium oxide, which can be prepared using techniques such as electron beam evaporation and sputtering. can be formed. The thickness of the protective layer is usually 0.01 to 10 μm, preferably 0.1 to 3 μm.
It is desirable to set it to m.

As the material for forming the electrode, many commonly used electrode materials can be effectively used. Specifically, for example, A A * A gt A u + P L + C
These materials are used to provide a predetermined size, shape, and thickness at a predetermined location by means of vapor deposition or the like.

The embodiment shown in Figure 2 was designed to improve the durability against dielectric breakdown of the electrode parts 37 and 38 that come into contact with the recording liquid (ink), and the figure shows an enlarged view of the heating element substrate. The shaded area 46 in FIG. 1 is the electrode protective layer.

Note that this pattern of the electrode protective layer is just an example, and instead of covering the entire surface as shown in the figure, it may be formed independently for each electrode. This electrode protective layer is provided to prevent the electrode from coming into contact with the recording liquid (ink). The electrode protective layer is not only in contact with the recording liquid itself, but is also subjected to extremely severe conditions in which the heating resistor layer (thermal energy acting part) is repeatedly subjected to heat cycles nearby. ing. The role of the electrode protective layer is to protect the electrode from dielectric breakdown under such conditions. Therefore, when forming an electrode protective layer, it is necessary to determine not only the material itself but also the relationship with the electrode material. The present inventor has developed a bubble-jet liquid injection method in which the volume resistivity of the electrode and the electrode protective layer are changed (this can be done by changing the material itself or by changing the production conditions to change the film quality of each layer). A recording head was prototyped, a jetting durability test was conducted, and it was found that dielectric breakdown of the electrodes is less likely to occur when the configuration satisfies the following relationship.

However, ρei: Volume resistivity of the heat-generating protective layer ρe: Volume resistivity of the electrode As the material constituting the electrode, many commonly used electrode materials can be effectively used.
As in the embodiment shown in the figure.

Al1. Examples include AK, Au, Pt, Cu, etc., and these are used to deposit them in a predetermined position, in a predetermined size, and by a method such as vapor deposition.
Available in different shapes and thicknesses.

As the material constituting the electrode protective layer, for example, organic epoxy resin, Teflon resin, polyethylene resin, etc. may be used. As an inorganic material, silicon oxide, silicon nitride, etc. can be formed using a technique such as sputtering.

Examples of materials useful for forming the heating resistor layer include tantalum nitride, nichrome, silver-palladium alloy, silicon semiconductor, hafnyl 11, lanthanum, zirconyl 11,
Examples include borides of metals such as titanium, tantalum, tungsten, molybdenum, niobium, chromium, and vanadium.

Among the materials constituting these heating resistor layers, metal borides are particularly excellent, and among these, hafnium boride has the best properties, followed by zirconium boride. , lanthanum boride, tantalum boride, vanadium boride, and niobium boride.

The heating resistor layer can be formed using the above-mentioned materials by techniques such as electron beam evaporation and sputtering. The thickness of the heating resistor layer is determined in accordance with its area, material, shape and size of the heat acting part, and actual power consumption, etc. so that the amount of heat generated per unit time is as desired. However, in normal cases, it is 0.001~5μ
m, preferably 0.01 to 1 μm.

Examples of useful materials for forming the protective layer include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, and zirconium oxide, which can be prepared using techniques such as electron beam evaporation and sputtering. can be formed. The thickness of the protective layer is usually 0.01 to 10 μm, preferably 0.1 to 3 μm.
It is desirable to set it to m.

Effects As is clear from the above explanation, according to the present invention, in a bubble jet liquid jet recording head, the durability of the heating element portion is significantly improved, the dielectric breakdown of the electrodes is made less likely to occur, and the durability is improved. can significantly improve performance.

[Brief explanation of the drawing]

1 and 2 are main part configuration diagrams for explaining the present invention in detail, and FIGS. 3 to 6 are diagrams for explaining an example of a liquid jet recording head to which the present invention is applied. figure,
FIGS. 7 to 10 are diagrams for explaining examples of conventional liquid jet recording heads. 32...Heating element substrate, 37.38...Electrode, 39.
... Heating element, 44... Heating element protective layer, 45... Electrode protective layer. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8"7 9 Figure

Claims (1)

[Scope of Claims] 1. A flow channel that contains a recording liquid to be introduced, generates bubbles in the recording liquid by heat, and is provided with a thermal energy acting section that generates an acting force as the volume of the bubbles increases. , an orifice that communicates with the flow path and causes the recording liquid to be ejected as droplets by the acting force; a liquid chamber that communicates with the flow path and introduces 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 thermal energy application section includes a heat generating resistor layer, at least one pair of electrodes electrically connected to the heat generating resistor layer, and a a protective layer provided on the resistor layer to prevent the heat generating resistor layer from coming into contact with the recording liquid, the volume resistivity of the heat generating resistor layer being ρh, and the volume resistivity of the protective layer being ρh; A liquid jet recording head characterized in that, when ρhi, the following relationship is satisfied: 10^1^5<ρhi/ρh. 2. A flow channel connected to the flow channel that accommodates the recording liquid to be introduced and is provided with a thermal energy acting section that generates bubbles in the recording liquid by heat and generates an acting force as the volume of the bubbles increases. an orifice for ejecting the recording liquid as droplets by the acting force; a liquid chamber for communicating with the flow path and introducing the recording liquid into the flow path; and a liquid chamber for introducing the recording liquid into the flow path; In the liquid jet recording head, the thermal energy application section includes a heating resistor layer, at least one pair of electrodes electrically connected to the heating resistor layer, and a heating resistor layer provided to cover the electrodes. and an electrode protective layer for preventing the electrode from coming into contact with the recording liquid, and when the volume resistivity of the electrode is ρe and the volume resistivity of the electrode protective layer is ρei, 10^1^7< A liquid jet recording head characterized in that it satisfies the relationship ρei/ρe.