JPS60116454A - Liquid jet recording head - Google Patents

Abstract

PURPOSE:To maintain a better liquid forming property by providing an electrothermal conversion body having a heat generating section formed thereon and a protective layer made of organic material at a portion excluding an orifice surface and the heat generating section on a certain area below a liquid passage of an electrode. CONSTITUTION:The main part of a liquid jet recording head 200 is composed of a base plate 202 for liquid jet recording (bubble jet: abbreviated to BJ) utilizing heat for discharge of liquid provided with a desired number of electrothermal conversion body 201 and a grooved plate 203 having a desired number of grooves provided corresponding to the electrothermal conversion body 201. The BJ substrate 202 and the grooved plate 203 are joined together with an adhesive or the like at a specified point so that a liquid passage 215 is formed with a part where the electrothermal conversion body 201 is provided on the BJ substrate 202 and the part of groove on the grooved plate 203 and has a heat acting part 206 as a part of the construction thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid jet recording head that performs recording by jetting liquid and forming flying droplets.

The inkjet recording method (liquid jet recording method) is capable of high-speed recording, in that the noise generated during recording is extremely small and can be ignored, and can be recorded without the need for special processing such as fixing on so-called plain paper. Recently, there has been a lot of interest in how it can be carried out.

Among them, for example, the liquid jet recording method described in Japanese Patent Application Laid-open No. 54-51837 and German Opening Publication (DOLS) No. 2848064 applies thermal energy to a liquid to obtain the motive force for ejecting droplets. In this respect, it has different characteristics from other liquid jet recording methods.

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

2- In particular, the liquid jet recording method disclosed in DOL8 2848064 is a so-called drop-on deman
d Not only is it very effectively applied to the Recording Act;
Since the recording head section can be easily implemented as a full 1ine type recording head with high density multi-orifice, it has the characteristic of being able to obtain high-resolution, high-quality images at high speed.

The recording head section of the apparatus applied to the above recording method is a part that communicates with an orifice provided for ejecting liquid and where thermal energy acts on the liquid in order to eject droplets. The apparatus includes a liquid discharge part having a liquid flow path in which a heat acting part is a part of the structure, and an electrothermal converter as a means for generating thermal energy.

This electrothermal converter includes a pair of electrodes, and a heat generating resistance layer connected to these electrodes and having a heat generating region (heat generating portion) between these electrodes.

Typical examples of the structure of such a liquid jet recording head are shown in FIG. 1(a), FIG. 1(b), and FIG. 1(C). Figure 1 (a) is a partial front view of the liquid jet recording head seen from the orifice side;
FIG. 1(a) is a partial cross-sectional view taken along the dashed line XY, and FIG. 1(c) is a partial view of the first protective layer 1.
11 is a plan view of the substrate with portion 11 removed. FIG.

The recording head 100 has a grooved plate 108 on the surface of a substrate 102 on which an electrothermal transducer 101 is provided, in which a predetermined number of grooves of a predetermined width and depth are provided at a predetermined linear density.
By joining so as to cover the orifice 104
It has a structure in which a liquid discharge part 105 is formed. In the case of the recording head shown in the figure, the recording head is shown as having a plurality of orifices 104, but the present invention is of course not limited to such a recording head, and the present invention also includes a recording head with a single orifice. It falls within the scope of this.

The liquid discharge section 105 has an orifice 104 at its terminal end for discharging the liquid, and thermal energy generated by the electrothermal converter 101 acts on the liquid to generate bubbles, causing rapid expansion and contraction of the volume. It has a heat acting part 106 which is a part that causes a state change.

The heat acting part 106 is the heat generating part 10 of the electrothermal converter 101.
The bottom surface thereof is a heat acting surface 108 which is located at the upper part of the heat generating section 7 and comes into contact with the liquid of the heat generating section 107.

The heat generating section 107 is a lower layer 1 provided on the substrate 102.
09. A heating resistance layer 110 provided on the lower layer 109
．． A first protective layer 11 provided on the heating resistance layer 110
1. The heating resistance layer 110 includes an electrode 118.1 for supplying current to the layer 110 to generate heat.
14 is provided on its surface. The electrode 11B is an electrode common to the heat generating part of each liquid discharge part, and the electrode 114 is
This is a selection electrode for selectively generating heat in the heat generating section of each liquid discharge section, and is provided along the liquid flow path of the liquid discharge section.

In the heat generating section 107, the first protective layer 111 protects the heat generating resistor layer 110 from the liquid used by chemically and physically protecting the heat generating resistor layer 110 and the liquid flow path of the liquid discharge section 105. The heating resistor layer 110 has a protective function of isolating the filling liquid and preventing a short circuit between the electrodes 118 and 114 through the liquid. The first protective layer 111 also has the role of preventing electrical leakage between adjacent electrodes. In particular, prevention of electrical leakage between each selection electrode, or prevention of electrical leakage caused by contact between the electrode and the liquid due to some reason between the electrodes under each liquid flow path. Preventing electrolytic corrosion is important, and for this purpose, the first protective layer 111 having the function of a protective layer is provided at least on the electrodes located below the liquid flow path.

The upper layers including the first protective layer have different characteristics depending on where they are provided.

That is, for example, in the heat generating part 107, (1) heat resistance, (2)
Liquid resistance, ■Liquid penetration prevention, ■Thermal conductivity, ■Antioxidation,
■It is required to have excellent insulation properties and ■tear resistance.
Areas other than the heat generating portion 107 are relieved by thermal conditions, but are required to have sufficiently excellent liquid penetration prevention properties, liquid resistance, and tear resistance.

However, there is currently no material constituting the upper layer that fully satisfies all of the above characteristics (■~■) as desired.
Currently, some of the characteristics of (2) are relaxed. That is, in the heat generating section 107, priority is given to ■, ■, and ■ in selecting the material;
In areas other than 7, for example, in the electrode part, priority is given to ①, ②, and ③ to select the material, and the upper layer is formed on the surface of each corresponding area using the corresponding material. It is formed.

On the other hand, 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,
The formation of each layer and the removal of a portion of the formed layer are repeated on the substrate, and at the stage where the upper layer is formed, the surface on which the upper layer is formed forms a step wedge.
Because it has a certain fine unevenness, the upper layer has good coverage at this step (5tep coverage).
has become important. In other words, if the coverage of this stepped portion is poor, liquid will penetrate into that portion, causing electrolytic corrosion or electrical breakdown. In addition, if the upper layer to be formed has a high probability of having defects due to the manufacturing method, liquid may penetrate through the defects.
This is a factor that significantly reduces the lifespan of electrothermal converters.

For these reasons, the upper layer must have good coverage at the stepped portion, and the probability that defects such as pinholes will occur in the formed layer is low, and even if they occur, they can be ignored in practical terms. Or even less is required.

Conventionally, in order to meet these demands, the upper layer is formed by laminating a first protective layer made of an inorganic insulating material and a second protective layer made of an organic material, or even a second protective layer made of an organic material. The first protective layer has a two-layer structure, the lower layer is made of an inorganic insulating material, and the upper layer is sticky, has relatively excellent mechanical strength, and has good adhesion to the first and second protective layers. For example, a third protective layer made of an inorganic material such as a metal is disposed on top of the second protective layer.

The second protective layer made of an organic material has excellent coverage but poor heat resistance and is therefore formed in a pattern as shown in FIG. 1(c). However, in the case of such a structure, partition walls of organic material are formed on the orifice surface formed by cutting, and the partition walls are subjected to force during cutting, resulting in a decrease in mechanical strength. A part of the flying droplets transmitted from the orifice surface penetrates into this portion where the mechanical strength has decreased, and the adhesion of the second protective layer decreases, causing layer peeling. For this reason, there is a problem in that electrical leakage to the liquid in the liquid flow path increases and stable flying droplets are not formed.

The present invention has been developed in view of the above points, and has excellent overall durability in frequent repeated use and long-term continuous use, and maintains good initial droplet formation characteristics over a long period of time. The main object of the present invention is to provide a liquid jet recording head that can be stably maintained.

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

Another object of the present invention is to provide a liquid jet recording head that has a high manufacturing yield even when it has multiple orifices.

The liquid jet recording head of the present invention includes an orifice provided for ejecting liquid to form flying droplets, and communicating with the orifice, so that thermal energy for forming the droplets acts on the liquid. A liquid discharge part has a liquid flow path that includes a heat acting part as a part of the structure, a common liquid chamber that stores the liquid to be supplied to the flow path, and an electric heating resistor layer provided on the substrate. an electrothermal transducer having at least one pair of opposing electrodes connected to each other and having a heat generating portion formed between the electrodes; A liquid jet recording head comprising at least an upper layer having a protective layer made of an organic material, wherein the protective layer of the organic material is formed on a portion excluding an orifice surface and a heat generating part. do.

The distance between the orifice surface and the organic material protective layer is at least 80
Preferably it is μm.

Hereinafter, the liquid jet recording head of the present invention will be specifically explained with reference to the drawings.

Figures 2(a), (1)), and (C) are similar to Figure 1(a), (1)), and (C).
These are preferred embodiments of the liquid jet recording head of the present invention corresponding to (a), (b), and (C), respectively.

In the liquid jet recording head shown in FIG. 2, the orifice side front view (FIG. 2(a)) is the same as FIG. 1(a), but the cross-sectional view through the liquid flow path (FIG. 2(b)) and the substrate Floor plan 2nd
As is clear from Figure (C), the second protective layer is not provided on the orifice surface and the heat generating portion.

The liquid jet recording head 200 shown in the figure includes a substrate 202 for liquid jet recording (bubble jet) (abbreviated as BJ) that utilizes heat for liquid ejection, on which a desired number of electrothermal transducers 201 are provided, and The main part thereof is constituted by a grooved plate 208 that spreads grooves provided corresponding to the heat exchanger 201 as desired.

The BJ board 202 and the grooved plate 208 are joined at predetermined locations with an adhesive or the like, so that the electrothermal converter 2 of the BJ board 202
A liquid flow path 215 is formed by the portion where 01- is provided and the groove portion of the grooved plate 208, and the liquid flow path 2
15 has a heat acting part 206 as a part of its configuration.

The BJ substrate 202 includes a support 216 made of silicon, glass, ceramics, etc., a lower layer 209 made of SiO2, etc. on the support 216, and a heating resistor layer 2.
10, and liquid flow paths 2 on both sides of the heating resistance layer 210.
15 along the common electrode 218 and the selection electrode 214, the portion of the heating resistance layer 210 that is not covered with the electrode, and the electrode 2.
], 8, and 21.4 are provided with a first protective layer 2], l.

The electrothermal converter 201 has a heat generating section 20 as its main part.
7, the heat generating section 207 includes a lower layer 209, a heating resistance layer 210, and a heating resistor layer 210.
The lower layer of the first protective layer 211 - made of an inorganic insulating material and the upper layer of the first protective layer 211 made of an inorganic material are laminated, and the surface of the upper layer of the first protective layer 211 is laminated. (Thermal action surface 208) is in direct contact with the liquid filling the liquid flow path 215.

Almost the majority of the surface of the selection electrode 214 is covered with the second protective layer 2
12 and the first protective layer 211 are stacked in this order from the electrode side. provided. The upper layers do not need to be formed in this order, starting with the first protective layer 21.1 from the selection electrode side. Second protective layer 212
may be formed in this order. Alternatively, the first protective layer 21
In the liquid jet recording head shown in FIG. It may be formed on the outermost layer. The lower layer of the first protective layer 211 is made of an inorganic insulating material such as an inorganic oxide such as 5i02 or an inorganic nitride such as Si3N.
The first layer is sticky, has relatively good mechanical strength, and has adhesion and adhesion to the lower layer of the first protective layer. For example, the lower layer of the first protective layer is formed of SiO□. In this case, it is made of a metal material such as Ta. By disposing a layer made of an inorganic material such as a metal that is relatively sticky and has mechanical strength on the upper layer of the first protective layer, it is possible to prevent the liquid from being discharged, especially on the heat acting surface 208. The shock from the cavitation action that occurs during this process can be sufficiently absorbed, and the life of the electrothermal converter 201 can be significantly extended. Even if the upper layer of the first protective layer 211 is formed as the eighth protective layer as described above, the same effect can be obtained.

The surface of the common electrode is covered with an upper layer formed by laminating the second protective layer 212 and the first protective layer in this order from the electrode side.

As the material constituting the lower layer of the first protective layer 211, an inorganic insulating material with relatively excellent thermal conductivity and heat resistance is suitable. For example, inorganic oxides such as 8102, titanium oxide, vanadium oxide, niobium oxide, molybdenum oxide, tantalum oxide, tungsten oxide, chromium oxide, zirconium oxide, hafnium oxide, lanthanum oxide, and yttrium oxide.

Transition metal oxides such as manganese oxide, as well as aluminum oxide, calcium oxide, and strontium oxide.

Metal oxides such as barium oxide, silicon oxide, and their composites, high resistance nitrides such as silicon nitride, aluminum nitride, boron nitride, tantalum nitride, and these oxides,
Even if the bulk resistance of semiconductors such as nitride composites and amorphous silicon and amorphous selenium is low, sputtering method, CVD method, vapor deposition method, vapor phase reaction method,
Examples include thin film materials that can be made to have high resistance through a manufacturing process such as a liquid coating method.

Materials that can form the first protective layer and the eighth protective layer include, in addition to the above-mentioned Ta, elements of group 1RLA of the periodic table such as Sc and Y, Ti, and Zr.

Group 1 Va elements such as Hf, Group Va elements such as V and Nb, Group Vi elements such as Cr1M09W, Fe
Group II elements such as , Co, and Ni; T 1-Ni
, Ta-W, Ta-Mo-Ni, Ni-Cr,
Fe-Co, Ti-W, Fe-Ti.

Alloys of the above metals such as Fe-Ni, Fe-Cr, Fe-Ni-Cr; Ti-B, Ta-B, Hf-B, W
-B borides of the above metals such as Ti-C, Zr-C
, V-C, Ta-C, Mo-C, Ni-C and other carbides of the above metals; Mo-8i, W-8i, Ta
-silicides of the above metals such as 8i; Ti-N, Nb-
Examples include nitrides of the above metals such as N and Ta-N. The upper layer of the first protective layer and the eighth protective layer can be formed using these materials by methods such as vapor deposition, sputtering, and CVD. The protective layer No. 8 may be the above-mentioned layer alone, but of course it is also possible to combine some of these layers.
The third protective layer is not limited to the above-mentioned material alone, but can also be used in combination with the material underlying the first protective layer, as in the case of the first protective layer shown in FIG.

The second protective layer 212 is made of an organic insulating material that has excellent liquid penetration prevention and liquid resistance properties, and has the following characteristics: ■ good film formability, ■ dense structure with few pinholes, and ■ use. It is desirable that the material has physical properties such as not swelling or dissolving in ink, (1) having good insulation properties when formed into a film, and (2) having high heat resistance. Such organic materials include the following resins, such as silicone resins, fluororesins,
Aromatic polyamide, addition polymerized polyimide, polybenzimidazole, metal chelate polymer, titanate ester, epoxy resin, phthalic acid resin, thermosetting phenol resin, P-vinylphenol resin, Zylock resin, triazine resin, BT resin ( Examples include triazine resin and bismaleimide addition polymer resin). In addition to this, the second protective layer 212 can also be formed by vapor depositing polyxylylene resin and its derivatives.

Furthermore, various organic compound monomers such as thiourea,
Thioacetamide, vinylferrocene.

1.8.5-) Licrobenzene, chlorobenzene.

Styrene, ferrocene, pyrroline, naphthalene.

Pentamethylbenzene, nitrotoluene, acrylonitrile, diphenylselenide, P-toluidine, P-xylene, N,N-dimethyl-P-)luidine, toluene, aniline, diphenylmercury, hex”J-)
tilbenzene, malononitrile.

Tetracyanoethene, thiophene, benzeneselenol, tetrafluoroethylene, ethylene.

N-nitron diphenylamine, acetylene, ■.

2.4-) The second protective layer 2 is formed by plasma polymerization using IJ chlorobenzene, fluoropane, etc.
12 can also be formed.

However, if a high-density multi-orifice type recording head is to be manufactured, an organic material that is extremely easy to process using fine photolithography is used as the material for forming the second protective layer 212, in addition to the above-mentioned organic materials. is desirable. Specifically, such organic materials include, for example, polyimide isoindoquinazolinedione (trade name: PIQ, manufactured by Hitachi Chemical), polyimide resin (trade name: PYRALIN, manufactured by DuPont), and cyclized polybutadiene (trade name: JSR-CBR, CBR-
Preferable examples include M 901° manufactured by Nippon Synthetic Rubber Co., Ltd.), Photoneese (trade name: manufactured by Toshi Co., Ltd.), and other photosensitive polyimide resins.

The lower layer 209 is provided as a layer that mainly controls the flow of heat generated from the heat generating section 207 toward the support body 216, and when applying thermal energy to the liquid in the heat acting section 206, , so that more heat generated from the heat generating section 207 flows toward the heat acting section 206, and when the electricity to the electrothermal converter 201 is turned off, the heat generating section 207
The constituent materials are selected and the layer thicknesses thereof are designed so that the heat remaining in 07 quickly flows to the support 216 side. Materials constituting the lower layer 209 include, in addition to the above-mentioned SiO□, inorganic materials typified by metal oxides such as zirconium oxide, tantalum oxide, magnesium oxide, and aluminum oxide.

As the material constituting the heat generating resistor layer 210, almost any material can be used as long as it generates desired heat when energized.

Specific examples of such materials include tantalum nitride, nichrome, silver-palladium alloy, silicon semiconductor,
Or hafnium, lanthanum.

Zirconium, titanium, tantalum, tungsten.

Preferred examples include gold layers such as molybdenum, niobium, chromium, and vanadium, alloys thereof, and borides thereof.

Among these materials constituting the heating resistance layer 210, metal borides can be cited as particularly excellent, and among them, hafnium boride has the most excellent properties.
This is followed by zirconium boride, lanthanum boride, tantalum boride, vanadium boride, and niobium boride.

The heat generating resistor layer 210 can be formed using the above-mentioned materials using techniques such as electron beam evaporation and sputtering.

As the material constituting the electrodes 213 and 214, many commonly used electrode materials can be effectively used.
Specifically, metals such as AllAg1Au and Pt1Cu can be used, and these are used to provide a predetermined size, shape, and thickness at a predetermined position by a method such as vapor deposition.

The materials constituting the components of the grooved plate 203 and the common liquid chamber provided on the upstream side of the heat acting section 206 are materials whose shape is not affected by thermal effects during the construction of the recording head or under the environment during use. It is possible to easily apply micro-precision machining because it is not susceptible or hardly susceptible, and it is also possible to easily obtain the desired surface accuracy, and furthermore, it is possible to Most materials are effective as long as they can be processed to allow liquid to flow smoothly.

Typical examples of such materials include ceramics, glass, metals, plastics, silicone wafers, and the like. In particular, glass and silicon wafer are suitable materials because they are easy to process and have appropriate heat resistance, thermal expansion coefficient, and thermal conductivity. If the liquid is water-based, the outer surface around the orifice 204 should be treated with water repellent treatment to prevent liquid from leaking and flowing around the outside of the orifice 204.
If the liquid is non-aqueous, it is better to apply oil repellent treatment.

The liquid jet recording head of the present invention will be specifically explained below with reference to Examples.

EXAMPLE The liquid jet recording head shown in FIG. 2 was manufactured as follows.

A 5 μm thick SiO□ film was formed by thermal oxidation of a Si wafer and used as a substrate. HfB2 was formed on the substrate as a heating resistance layer to a thickness of 1500A by sputtering, and then a Ti layer 50A and an AI layer 5000X were successively deposited by electron beam evaporation.

A pattern as shown in FIG. 2(C) was formed by a photolithography process, and electrodes 218 and 214 were formed. The size of the heat-active surface was 80 μm wide, 150 μm long, and 150 ohms including the AI main electrode resistance.

Next, a 20 μm thick PIQ layer was formed as a second protective layer 212 on the shaded area in FIG. 2(c) according to the following steps.

That is, the support on which the heating resistance layer and electrodes were formed in a predetermined pattern was washed and dried, and then coated with the PIQ solution using a spinner (the spinner rotation conditions in the coating conditions were: 500 rpm in the first step;
c, second step 4000 rpm + 40 sec). Next, leave it at 80℃ for 10 minutes, and after drying the solvent,
Temporary baking was performed at 0°C for 60 minutes.

On top of this, photoresist OMR-s 8 (manufactured by Tokyo Ohka)
was applied using a spinner, dried, exposed using a mask aligner, and developed to obtain a desired PIQ layer pattern. Next, the PIQ layer was etched at room temperature using a PIQ etchant. After washing with water and drying, the stripping solution for OMR resist was removed, and baking was performed at 350° C. for 60 minutes to complete the process of forming a PIQ layer pattern.

The thickness of the PIQ layer is 2.0 μm on the heating resistor layer on the support, where there is no electrode, and 1.8 μm on the top surface of the heating resistor layer and electrode.
It was m. This shows that the 5tep coverage property is good.

Following the formation of the PIQ@ pattern, a 5IO2 sputtered layer of 2.2 μm was deposited as a lower layer of the first protective layer 211 by high rate sputtering, and a Ta layer of 0.5 μm was further deposited as an upper layer of the first protective layer 211 by Ta sputtering. Laminated thickly.

Next, a grooved glass plate was adhered to the BJ substrate in a predetermined manner. That is, as shown in FIG. 2(b), BJ
Grooved glass plate for forming an ink introduction channel and a heat acting part on the substrate (groove size width 50 μm x depth 50 μm x length 'l)
trrm) is glued.

The electrothermal transducer of the recording head created in this way has a temperature of 10
When a μs aOV rectangular voltage of 800 H2 is applied, liquid is ejected from the orifice according to the applied signal, and flying droplets are stably formed.In addition, the leakage current that occurred in the conventional 107 pulse platform can be reduced. The increase is gone and 8
Flying droplets were stably formed up to 1.08 pulses.

As described above, the liquid jet recording head of the present invention can stably maintain good initial droplet formation characteristics over a long period of time, has high reliability in manufacturing processing, and has low manufacturing yield when made into a multi-orifice structure. It was also expensive.

[Brief explanation of the drawing]

FIGS. 1(a), (b), and (C) are for explaining the configuration of a conventional liquid jet recording head, respectively. FIG. 1(a) is a schematic front partial view, and FIG. b) is a partial cross-sectional view taken along the dashed-dotted line XY in Fig. 1(a), Fig. 1(C)
are schematic plan views of the BJ board, Figures 2(a) and (b)
, (C) are schematic plan views of a BJ substrate corresponding to FIG. 1 (C) for explaining the structure of the liquid jet recording head of the present invention. 100.200: Liquid jet recording head 101.20
1: Electrothermal converter 102.202: Substrate 108.208: Grooved plate 104.204: Orifice. 105: Liquid discharge part 106.206: Heat action part 107.207: Heat generation part 108.208: Heat action surface 109.209: Lower layer 110.210: Heat generating resistance layer 111.211: First protective layer (upper layer) 112.
212: Second protective layer (upper layer) -9ζ - 118,218: Common electrode 114.214: Selection electrode 215: Liquid flow path 216: Support patent applicant Canon Inc. 26-

Claims (1)

[Claims] It comprises an orifice provided for ejecting liquid to form flying droplets, and a heat acting part that communicates with the orifice and is a part where thermal energy acts on the liquid to form the droplets. A liquid discharge part having a liquid flow path as a part, a common liquid chamber storing the liquid to be supplied to the flow path, and at least one pair of an electrothermal converter comprising opposing electrodes and a heat generating portion formed between these electrodes; and a protective layer made of at least an organic material on at least a portion of the electrodes that is below the liquid flow path. What is claimed is: 1. A liquid jet recording head comprising: an upper layer having a top layer comprising: a protective layer made of an organic material;