JPH0584910A - Liquid jet recording head - Google Patents

Abstract

PURPOSE:To increase durability of a protective layer in complicated repetitive use of a recording head and in its continuous use for long time. CONSTITUTION:In a liquid jet recording head which has a liquid discharge opening for discharging recording liquid, a heat energy generating means for feeding discharge energy to the recording liquid, and a protective layer provided on the heat energy generating means, and is composed of, at least, one pair of wiring electrodes 3 wherein the heat energy generating means is electrically connected to a heating element layer 2 and the heating element layer 2, the protective layer 4 is provided by, at least, not less than two layers, and a depressed part is provided to, at least, one layer of the protective layers 401 under the upmost protective layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid jet recording head, and more particularly to a liquid jet recording head for jetting a recording liquid used in a liquid jet recording system to form flying droplets of the recording liquid. Is.

[0002]

2. Description of the Related Art The ink jet recording method (liquid jet recording method) is extremely small in the generation of noise during recording and enables high-speed recording, and does not require a special fixing process on plain paper. Recently, there has been much interest in being able to record.

Among them, for example, JP-A-54-51837.
The liquid jet recording method described in Japanese Laid-Open Patent Publication No. 2843064 and German publication (DOLS) No. 2843064 is another liquid jet recording method in that thermal energy is applied to the liquid to obtain a driving force for ejecting droplets. It has different characteristics from the law.

That is, in the recording method disclosed in the above publication, the liquid subjected to the action of thermal energy causes a state change accompanied by a sharp increase in volume, and the action force based on the state change causes the recording head portion to change. Liquid is ejected from the orifice at the tip to form flying droplets, and the droplets adhere to the recording member to perform recording.

In particular, the liquid jet recording method disclosed in DOLS 2843064 is a so-called drop method.
-On-demand recording method is not only very effectively applied to the recording method,
Since a recording head with a high density multi-orifice type can be easily embodied, it has a feature that a high resolution and high quality image can be obtained at a high speed.

The recording head portion of the apparatus applied to the above-mentioned recording method communicates with an orifice provided for ejecting a liquid, and thermal energy for ejecting a liquid drop acts on the liquid. It is provided with a liquid discharge part having a liquid flow path whose part is a heat acting part, and an electrothermal converter as means for generating heat energy.

The electrothermal converter comprises a pair of electrodes, and a heating resistance layer having a region (heat generating portion) connected to the electrodes and generating heat between the electrodes.
The pair of electrodes is generally composed of a selection electrode and a common electrode, and by supplying electricity between these electrodes, heat energy for ejecting a suitable liquid from the orifice is generated from the heat generating portion.

A protective layer is usually provided on these heat generating portions and at least on the electrodes provided under the region where the liquid flows or stays in the recording head. The protective layer chemically and physically protects the electrodes and the heat-generating resistance layer forming the heat generating portion from the liquid above them, and also prevents short circuit between the electrodes caused by the liquid and It is provided in order to prevent leakage between the same kind of electrodes, in particular, the selection electrodes, and further to prevent electrolytic corrosion of the electrodes caused by contact between the liquid and the electrodes and electric conduction to the electrodes.

The protective layer has different required properties depending on the place where it is provided. For example, on the heat generating portion, heat resistance, liquid resistance, liquid permeation prevention, thermal conductivity, oxidation resistance, and insulation are provided. And is required to have excellent puncture resistance, and is relaxed under thermal conditions in areas other than the heat-generating part, but is sufficiently excellent in liquid permeation prevention, liquid resistance, insulation and puncture resistance. Is required.

However, a single protective layer material capable of covering all of the above-mentioned properties (1) to (3) with only one protective layer and covering all of the heat generating portion and the electrode is desired. In the actual recording head, various materials that complement each other in characteristics required depending on the place where the recording head is provided are selected, and the protective layer is formed by a plurality of layers made of these materials. In such a multi-layered protective layer, the adhesive force between the newly laminated overlapping layers is sufficiently strong, and adhesion such as peeling or rising between layers is caused during the manufacturing process of the recording head and the actual use period. It is required that a failure due to a decrease in force does not occur.

On the other hand, in addition to these, in the case of a multi-orifice type liquid jet recording head, in order to simultaneously form a large number of fine electrothermal transducers on the substrate, in the manufacturing process, on the substrate. The formation of each layer and the removal of a part of the formed layer are repeated, and at the stage of forming the protective layer, the surface on which the protective layer is formed has fine unevenness with step edges (steps). Therefore, the coverage of the protective layer on the stepped portion (Step cover
age property) is important. That is, if the coverage of the step portion is poor, the liquid may penetrate into the step portion, which may cause electrolytic corrosion or electrical breakdown. Also,
In the case where the protective layer formed has a high probability of producing a defective portion in the manufacturing method, permeation of the liquid occurs through the defective portion, which is a factor that significantly shortens the life of the electrothermal converter.

For these reasons, the protective layer has good coverage in the step portion, and the probability that defects such as pinholes are generated in the formed layer is low, and even if it occurs, it can be practically ignored. It is further required to be of the order of magnitude or less.

Particularly on the heat-acting surface, the liquid on the heat-acting surface is exposed to the harsh conditions in which a cycle of thousands of vigorous temperature changes between high temperature and low temperature is repeated per second, and the liquid on the heat-acting surface is vaporized at high temperature. The pressure changes that the pressure in the liquid flow passage decreases as the temperature rises, the pressure in the liquid flow passage increases, and the vaporized liquid condenses as the temperature decreases and the bubbles disappear. It is repeated and the mechanical stress caused by them is constantly being applied. For this reason,
The protective layer provided so as to cover at least the upper surface of the heat generating portion is required to have excellent impact resistance against mechanical stress and excellent adhesiveness between a plurality of layers constituting the protective layer.

However, in the conventional liquid jet recording head, the above-mentioned various requirements cannot be sufficiently satisfied, and in particular, the peeling of the multi-layered protective layer provided on the upper surface of the heat generating portion between the multiple layers is long. When such a liquid jet recording apparatus is used, it cannot be prevented, and such peeling often occurs. In addition, a manufacturing process of the recording head, for example, a process of forming a liquid flow path on a substrate provided with an electrothermal converter protected by a protective layer, a recording head for separating the recording head or for forming an orifice. In the step of cutting, etc., the adhesiveness between the plurality of layers forming the protective layer was likely to deteriorate, and peeling between the layers was likely to occur. On the other hand, the protection formed by giving priority to designing the protective layer so as to sufficiently satisfy the above-mentioned characteristics required depending on the place where the protective layer is provided, or by forming a slight variation in conditions when laminating the protective layer. In many cases, the thickness of each layer was out of balance, and the adhesion between the layers was not sufficient.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is excellent in durability in frequent repeated use of a recording head and continuous use for a long time.
A main object of the present invention is to provide a liquid jet recording head capable of stably forming good droplets for a long period of time.

Another object of the present invention is to provide a liquid jet recording head which is highly reliable in manufacturing and processing.

A further object of the present invention is to provide a liquid jet recording head having a high manufacturing yield even when a multi-orifice is used.

[0018]

In order to achieve such an object, a liquid jet recording head according to the present invention is provided with a liquid ejection port for ejecting a recording liquid and an ejection energy for the recording liquid. Of heat energy generating means and a protective layer provided on the heat energy generating means, wherein the heat energy generating means includes a heating resistance layer and at least a pair of wiring electrodes electrically connected to the heating resistance layer. In the liquid jet recording head, the protective layer has at least 2
One or more layers are provided, and the recess is provided in at least one protective layer below the uppermost protective layer.

[0019]

According to the present invention, at least two or more protective layers are provided, and at least one protective layer below the uppermost protective layer is provided with a recess, thereby increasing the bonding area between the protective layers and making a bite. It is possible to reinforce the joining force by and to increase the impact resistance against mechanical stress.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings.

FIG. 1A is a plan partial view of the vicinity of a heat generating portion of a liquid jet recording head, and FIG. 1B is a cutting view taken along a dashed line XY in FIG. 1A. FIG.

In FIG. 1, the substrate 1 comprises a support 101 made of silicon, glass, ceramics or the like, and a lower layer 102 made of SiO ₂ or the like on the support 101.

The lower layer 102 is provided as a layer for controlling the flow of heat mainly generated from the heat generating portion 6 to the support 101 side, and is used when heat energy is applied to the liquid on the heat acting surface 5. Causes more heat generated from the heat generating portion 6 to flow toward the heat acting surface 5 side, and when the electricity to the electrothermal converter 7 is turned off, the heat remaining in the heat generating portion 6 is The selection of the constituent materials and the design of the layer thickness are made so that they flow quickly to the support 101 side. Lower layer 1
Examples of the material constituting 02 include inorganic materials represented by metal oxides such as zirconium oxide, tantalum oxide, magnesium oxide, and aluminum oxide, in addition to the above-described SiO ₂ .

The heating resistor layer 2 is laminated on the upper part of the substrate, and the electrode layer 3 is further laminated on the upper part thereof. The heating resistance layer 2 and the electrode layer 3 are selectively removed from the substrate 1 by a photoetching method or the like while leaving a desired shape. In the heat generating portion 6, as shown in FIG. 1, the electrode layer 3 is removed from the heating resistance layer 2 and patterned so that the ends thereof face each other with a predetermined distance. The removed portion of the heating resistor layer 2 of the electrode layer 3 is the electrode layer 3
It becomes an area (heat generation part 6) that generates heat by energizing the.

As the material forming the heat generating resistance layer 2, almost any material can be adopted as long as it can generate desired heat when energized.

Among such materials, metal borides can be mentioned as excellent ones. Among them, hafnium boride has the most excellent characteristics, and then zirconium boride and boride are most excellent. Lanthanum, vanadium boride,
The order is niobium boride.

The layer thickness of the heating resistance layer 2 depends on the area, the material, the shape and size of the heat-acting portion, and the power consumption in practice so that the amount of heat generated per unit time is as desired. It is determined, but preferably 0.
001 to 5 μm, and more preferably 0.01 to 1 μm.

As the material constituting the electrode layer 3, many of the commonly used electrode materials are effectively used.
Specific examples include metals such as Al, Ag, Au, Pt, and Cu.

On the surface of the substrate 1 on which the heating resistance layer 2 and the electrodes 3 are formed, a protective layer 4 is further laminated as an upper part.

In the protective layer of the present invention shown in FIG. 1, the protective layer 4 includes a first protective layer (hereinafter abbreviated as a first layer) 401 and a second protective layer (hereinafter simply referred to as a second layer). (Abbreviated as “layer”) 401.

The protective layer 4 has the characteristics described above as a protective layer provided on the heat generating portion 6, and in consideration of the adhesiveness with the substrate 1 and the adhesiveness between the layers forming the protective layer 4, the respective layers are protected. Materials are selected and configured.

The first layer laminated as the lowermost layer of the protective layer 4.
The layer 401 is provided mainly for maintaining the insulating property between the electrodes 3 which are provided on the heating resistance layer 2 so as to face each other.

[0033] As the material constituting the first layer 401, excellent insulating properties and excellent relatively thermal conductivity and heat resistance, also for example of adhesion to the substrate 1, an inorganic oxide such as SiO ₂ And inorganic insulating materials such as inorganic nitrides such as Si ₃ N _{4 and the} like.

As the material forming the first layer 401, titanium oxide, vanadium oxide, in addition to the above-mentioned inorganic materials,
Transition metal oxides such as niobium oxide, molybdenum oxide, tantalum oxide, tungsten oxide, chromium oxide, zirconium oxide, hafnium oxide, lanthanum oxide, yttrium oxide, and manganese oxide, as well as aluminum oxide, calcium oxide, strontium oxide, barium oxide, and oxidation. Metal oxides such as silicon and their composites, silicon nitride, aluminum nitride, boron nitride, tantalum nitride and other high resistance nitrides, and composites of these oxides and nitrides,
Further, in the bulk such as semiconductors such as amorphous silicon and amorphous selenium, a thin film material that can have high resistance in the manufacturing process such as sputtering method, CVD method, vapor deposition method, gas phase reaction method, liquid coating method, etc. The layer thickness is preferably 0.1 to 5 μm.
m, more preferably 0.2 to 3 μm, and particularly preferably 0.5 to 3 μm.

The second layer 402, which is laminated as an upper layer of the protective layer 4, is located in a portion of the liquid flow path provided above the heat generating portion 6 and in direct contact with the liquid. The protective layer 4 is mainly provided with reinforcement of liquid permeation preventive property, liquid resistance and mechanical strength.

The material forming the second layer 402 is a material that is viscous and relatively excellent in mechanical strength, and is also excellent in thermal conductivity, liquid resistance and liquid permeation prevention property. as, for example Sc, periodic table III _a group element such as Y, Ti, Zr, the IV _a-group element, such as Hf, Ta,
Group V _a elements such as V and Nb, and Group VI elements such as Cr, Mo and W
elements _a group, Fe, Co, metal consisting of elements of Group VIII such as Ni or the like; Ti-Ni, Ta-W , Ta-Mo-N
i, Ni-Cr, Fe-Co, Ti-W, Fe-Ti,
Alloys of the above metals such as Fe-Ni, Fe-Cr, and Fe-Ni-Cr; Borides of the above metals such as Ti-B, Ta-B, Hf-B, WB; Ti-C, Zr-C. , V-C,
Carbides of the above metals such as Ta-C, Mo-C and Ni-C; silicides of the above metals such as Mo-Si, W-Si and Ta-Si; such as Ti-N, Nb-N and Ta-N. Examples thereof include nitrides of the above metals. The second layer can be formed by a method such as a vapor deposition method, a sputtering method or a CVD method using these materials, and the film thickness thereof is preferably 0.01 to 5 μm, more preferably 0.1 to 5 μm. 5 μm,
Particularly preferably, the thickness is 0.2 to 3 μm.

Second layer 402 made of such a material
By providing the protective layer 4 on the surface of the protective layer 4, it is possible to sufficiently absorb the shock due to the cavitation effect generated when the liquid is ejected on the heat acting surface 5, and it is possible to remarkably extend the life of the heat generating portion.

In the first layer 401 of the protective layer, the recess is provided in the region excluding the heat acting surface.

The role of the concave portion of the first layer of this embodiment is that the first
The bonding area between the layer 401 and the second layer 402 is increased, and the second
It is to strengthen the adhesive force between the first layer 401 and the second layer 402 by strengthening the bonding force of the layer 402 due to the biting of the first layer 401.

The formation of the recess is performed by the photoetching method.

The etching depth, which is the amount of depression of the recess, is
From the viewpoint of adhesiveness, deeper is preferable, but it is set within a range that does not deteriorate the characteristics such as liquid resistance, insulation, and damage resistance required for the protective layer.

The etching depth is preferably 1/2 or less of the thickness of the protective layer for forming the concave portion, that is, the thickness of the first layer 401 in the present embodiment, and the upper protective layer, that is, the second thickness in the present embodiment.
It is preferable that the thickness of the layer 402 be 1/2 or less.

If a concave portion is formed on the heat acting surface, it is not preferable because it affects discharge characteristics, durability and the like.
It is not preferable to form a recess near the stepped portion of the wiring because it affects the insulation and durability.

Therefore, it is preferable to provide a concave portion other than near the heat acting surface and the step portion of the wiring. The shape and size of the recess can be set within a range that does not deteriorate the characteristics required for the protective film.

From the viewpoint of adhesiveness, it is advantageous to form fine and high-density recesses. Further, from the viewpoint of the covering property of the upper protective layer, the shape of the recess is circular and the size is 1 μm.
The above is preferable.

The protective layer does not have to be two layers, and even with three or more protective layers, a recess may be formed in the lower protective layer between the protective layers which are required to have enhanced adhesiveness.

Therefore, when the protective layer is multi-layered, the protective layer forming the recess need not be a single layer and can be selected as required.

Further, on a substrate provided with a heat generating portion formed by an electrothermal converter protected by a protective layer 4 as shown in FIG. 1, a liquid flow path and an orifice corresponding to the heat generating portion. The liquid jet recording head of the present invention is completed by forming.

FIG. 2 is a schematic exploded perspective view of an example of one embodiment of the completed liquid jet recording head.

In this recording head, a photosensitive resin dry film is laminated on a substrate 201, exposed and developed by a predetermined pattern mask, and a flow path wall 203 corresponding to a heat generating portion on the substrate and a common liquid chamber 205. And a top plate 207 having an orifice 208 made of a glass plate, a plastic plate, or the like is further laminated and bonded onto the flow path wall using an epoxy adhesive. In this recording head, an orifice is provided in the ceiling portion of the liquid flow path 202 having a heat acting surface, facing the heat acting surface.

FIG. 3 is a schematic perspective view of a liquid jet recording head according to another embodiment of the present invention manufactured by the same method.
In this recording head, the orifice 302 is provided in the direction of the liquid flow path 304, and the ink supplied from the ink supply port 306 and stored in the common liquid chamber 305 is used as the heat generating portion 303.
Orifice 302 due to the thermal energy generated by
The recording medium is ejected from the recording medium and adheres to the recording paper or the like for recording.

EXAMPLE A Si wafer was subjected to a thermal oxidation method to obtain SiO _{2 having} a thickness of 5 μm.
A film was formed and used as the substrate 1. The H _f B ₂ of 1500Å thickness was formed as a heat generating resistor layer 2 by a sputtering method on the substrate 1, followed of 50Å thickness by electron beam evaporation method Ti
Layer, an Al layer 3 as an electrode having a thickness of 5000 Å was continuously deposited.

An Al layer 3 having a predetermined pattern is formed by a photolithography process, and the size of the heat acting surface is a width of 30.
The length was 150 μm. The total resistance of the heating resistance layer and the Al electrode was 150Ω.

Next, SiO ₂ was laminated on the entire surface of the substrate 1 by the high rate sputtering method to a thickness of 2.5 μm. A predetermined pattern was formed on the SiO ₂ layer 401 by a photolithography process. The pattern of the recesses had a circular diameter of 2 μmφ and a depth of 0.3 μm and was arranged at a pitch of 10 μm in the region excluding the heat acting surface and the wiring step portion.

This circular recess can be formed as follows. First, a photoresist (trade name: OFPR-800, manufactured by Tokyo Ohka Co., Ltd.) is coated on SiO ₂ to a film thickness of 2 μm and prebaked, and the prebaked coating film is masked by a conventional method. Exposure, development, and post-baking were performed. The pre-baking condition was 90 ° C. for 30 minutes,
The exposure was performed by irradiating 10 mJ / cm ² of ultraviolet rays through a mask. Development was carried out at 25 ° C. for 1 minute. Post-baking was performed at 140 ° C. for 30 minutes.

Then, reactive etching is performed,
The photoresist was removed to complete the patterning. The conditions of this reactive are: high frequency power: 500 W, etching time: 10 minutes, base pressure: 1 × 10 ⁻³ Pa or less, etching gas: CF ₄ , etching gas pressure: 3P
It was a. In this way, a circular recess was formed.

Next, a Ta layer, which is the second layer 402, was deposited on the first layer 401, which was a SiO ₂ layer, to a thickness of 6000 Å by a sputtering method to complete the protective layer.

A thickness of 5 is formed on the substrate thus formed.
A photosensitive resin drum of 0 μm is laminated, exposed and developed with a predetermined pattern mask to provide a liquid flow path and a common liquid chamber corresponding to the heat generating portion on the substrate, and further used as an epoxy adhesive. Then, glass top plates were laminated to prepare a liquid jet recording head as shown in FIG.

Comparative Example Except for forming a pattern of recesses in SiO ₂ .
A liquid jet recording head was manufactured in the same manner as in the above-described example.

Comparative Experiments 100 liquid ejecting recording heads were manufactured in each of the examples and the comparative examples, liquid was actually ejected, and an ejection durability test was performed to compare the durability.

The voltage applied to the heating resistor is the minimum voltage required to eject the liquid, and is multiplied by 1.15. The pulse width is 8 μs
ec, the pulse frequency was 1 KHz. As a result, no failure occurred due to peeling between the layers forming the protective film of the liquid jet recording head according to the example.

(Others) The present invention is provided with a means (for example, an electrothermal converter or a laser beam) for generating heat energy as energy used for ejecting ink, particularly in the ink jet recording system. The present invention provides excellent effects in a recording head and a recording apparatus of the type in which the thermal energy causes a change in ink state. This is because such a system can achieve high density recording and high definition recording.

Regarding the typical structure and principle thereof, see, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal as a result
This is effective because bubbles can be formed inside. Due to the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection openings to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the straight liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications, U.S. Pat. No. 4,558,333, U.S. Pat. No. 44, which discloses a configuration in which a heat acting portion is arranged in a bending region.
The configuration using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in Japanese Patent Laid-Open No. 59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads or a configuration as one recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the ink jet from the main body of the apparatus is electrically connected to the main body of the apparatus by mounting the recording head. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add ejection recovery means of the recording head, preliminary auxiliary means and the like because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping means, a cleaning means, a pressure or suction means for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads to be mounted, for example, only one is provided corresponding to a single color ink, and a plurality of inks having different recording colors and densities are supported. A plurality of pieces may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but may be either integrally formed of the recording heads or a combination of a plurality of them. The present invention is also very effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet method, it is common to adjust the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. At times, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy for changing the state of the ink from the solid state to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in a standing state. You may use the ink liquefied by. In any case, by applying heat energy such as ink that is liquefied by applying heat energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP 54-56847 A or JP 60-7.
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus of the present invention, besides the one used as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function can be used. It may be in a form or the like.

[0071]

As described above, according to the present invention,
By providing at least two or more protective layers and forming a recess in at least one protective layer below the uppermost protective layer, the bonding area between the protective layers is increased, and the bonding force by biting is strengthened to improve mechanical strength. Impact resistance to stress can be increased.

Further, according to the present invention, since a plurality of protective layers are laminated with a strong adhesive force, when the recording head is repeatedly used or continuously used for a long time, a failure such as peeling between layers of the protective layer does not occur. Good droplets can be stably discharged without being generated, and reliability is improved and yield is improved.

[Brief description of drawings]

1A and 1B are a plan view and a sectional view in the vicinity of a heat generating portion provided on a substrate of a liquid jet recording head of the present invention.

FIG. 2 is a schematic exploded perspective view of an embodiment of a liquid jet recording head of the present invention.

FIG. 3 is a schematic perspective view of an embodiment of a liquid jet recording head of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Heating resistance layer 3 Electrode layer 4 Protective layer 5 Thermal action surface 6 Heat generation part 7 Electrothermal converter 101 Substrate support 102 Lower layer 201,301 Substrate 202,304 Liquid flow channel 203 Flow channel wall 204 Communication hole 205 , 305 Common liquid chamber 206 Second common liquid chamber 207, 307 Top plate 208, 302 Orifice 303 Heat generating part 306 Ink supply port 401 First layer 402 Second layer

Claims (1)

[Claims] 1. A liquid ejecting port for ejecting a recording liquid, a thermal energy generating unit for supplying an ejecting energy to the recording liquid, and a protective layer provided on the thermal energy generating unit. In the liquid jet recording head, wherein the thermal energy generating means is composed of a heat generating resistance layer and at least a pair of wiring electrodes electrically connected to the heat generating resistance layer, at least two protective layers are provided, and the uppermost protection is provided. A liquid jet recording head, wherein a recess is provided in at least one protective layer below the layer.