JPH02187354A - Base for liquid jet recording head and liquid jet recording head using - Google Patents

Abstract

PURPOSE:To improve general durability, printing quality as a liquid jet recording head by forming a protective layer of an organic material provided on an electrode inside from the edge line of a base. CONSTITUTION:An electrothermal converter 101 has a heat generator 107 as its essential section. The heat generator 107 is sequentially laminated from a base plate side with a lower layer 109, a heat generating resistor layer 110, and lower and upper layers of a first protective layer 111 composed of an inorganic insulating material on a base plate 116, and the surface (heat operating surface) of the upper layer of the protective layer 111 is brought into direct contact with liquid in a liquid passage. The most surface of a selecting electrode 114 is covered with an upper layer laminated sequentially from an electrode side with a second protective layer 112 and the first protective layer 111. The lower layer of the first protective layer 111 is composed, for example, of an inorganic insulating material such as inorganic nitride, etc., such as Si3N4, etc., and composed of metal material of Ta, etc. Thus, a layer made of an inorganic material having mechanical strength with relatively high viscosity such as metal is disposed on the upper layer of the protective layer 111 to sufficiently absorb a shock due to cavitation generated in case of discharge of liquid, thereby prolonging the life of the electrothermal converter 101.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid jet recording head that performs recording by jetting liquid and forming flying droplets, and a recording head substrate that constitutes the recording head.

[Conventional technology]

A liquid jet recording head includes an orifice provided for ejecting liquid, and a heat acting part that communicates with the orifice and acts on the liquid to form droplets. a liquid discharge section having a liquid flow path;
It is equipped with 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 FIGS. 2(a) to 2(c). FIG. 2(a) is a perspective view of the liquid jet recording head, and FIG. 2(b) is a perspective view of the liquid jet recording head.
It is a partial view cut along the X-Y line in FIG. 2(a), and FIG. 2(c) is a plan view of the base before being divided into individual heads.

The recording head 200 includes a grooved plate 20 in which a predetermined number of grooves of a predetermined width and depth are provided at a predetermined linear density on the surface of a base body 202 on which an electrothermal transducer 201 is provided.
Join so as to cover with 3. Further, an orifice plate 217 having an orifice 204 serving as a liquid discharge port is provided in accordance with the layer.

Although the recording head shown in the figure is shown as having a plurality of orifices 204, the present invention is of course not limited to such a recording head, and a recording head with a single orifice is also applicable to the present invention. It falls under Noriharu.

The liquid flow path 215 has an orifice 204 at its end for discharging liquid, and thermal energy generated by the electrothermal converter 201 acts on the liquid to generate bubbles, causing rapid expansion and contraction of the volume. It has a heat acting part 206 which is a part that causes a state change.

The heat acting part 206 is the heat generating part 20 of the electrothermal converter 201.
7 and has a heat acting surface 208 as a surface in contact with the liquid of the heat generating section 207 as its bottom surface.

The heat generating section 207 is a lower layer 2 provided on the base 202.
09. Heat generating resistance layer 210 provided on the lower layer 209
, a first protective layer 21 provided on the heat generating resistance layer zio.
1. The heating resistance layer 210 includes an electrode 213.2 for supplying electricity to the core layer 210 to generate heat.
14 is provided on its surface. The electrode 213 is a common electrode for the heat generating part of each liquid discharge part, and the electrode 214 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 generation section 207, the first protective layer 211 fills the heat generation resistance layer 210 and the liquid flow path of the liquid discharge section 205 in order to chemically and physically protect the heat generation resistance layer 210 from the liquid used. The heating resistor layer 210 has a protective function of isolating the electrodes 213 and 214 from the liquid and preventing a short circuit between the electrodes 213 and 214 through the liquid. Furthermore, the first protective layer 211 also plays a role in preventing electrical leakage between adjacent electrodes. In particular, between each selected electrode 21
It is important to prevent electrical leakage in step 4, or to prevent electrolytic corrosion of the electrodes that occurs when the electrodes under each liquid flow path come into contact with the liquid for some reason and are energized. For this purpose, a first protective layer 211 having the function of a protective layer is provided at least on the electrode located below the liquid flow path.

The upper layers including the first protection M have different required characteristics depending on the location where they are provided.

That is, for example, in the heat generating section 207, (1) heat resistance, (2)
Liquid resistance, ■Liquid penetration prevention, ■Thermal conductivity, ■Antioxidation,
■Excellent insulation properties and ■tear resistance are required, which can be alleviated by thermal conditions in areas other than the heat generating part 207, but liquid permeation prevention properties, liquid resistance, and rupture resistance are required. It is required to be excellent.

However, there is currently no material constituting the upper layer that sufficiently satisfies all of the above characteristics (■) to (■) as desired;
Currently, some of the characteristics of ~■ are relaxed and used. That is, in the heat generating section 207, priority is given to ■, ■, and ■ when selecting the material, while in other parts other than the heat generating section 207, for example, in the electrode section, priority is given to ■, ■, and ■. The selection of materials is then made, and the upper layer is formed with each corresponding material on each corresponding area surface.

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, each layer is formed on the substrate. At the stage where the upper layer is formed by repeatedly removing a portion of the formed layer, the surface on which the upper layer is formed has a fine unevenness with step wedge parts (steps). The step coverage of the upper layer in this stepped portion is important. In other words, if the coverage of this stepped portion is poor, liquid will penetrate into that portion, leading to electrolytic corrosion or electrical breakdown. Furthermore, if there is a high possibility that the formed upper layer will have defects due to the manufacturing method, liquid will penetrate through the defects, which will significantly reduce the lifespan of the electrothermal converter. There is.

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 must be to a practically negligible level or more. less is required.

Conventionally, in order to meet these requirements, 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 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 good mechanical strength, and adheres closely to the first and second protective layers. It may be made of an inorganic material such as metal, which has elasticity and adhesive properties, or it may be made of a second material.
Further above the protective layer, a third protective layer made of an inorganic material such as metal is disposed.

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. 2(c).

[Problems to be Solved by the Invention] However, in the conventional example described above, when cutting and dividing the head substrate into desired sizes, the organic material is usually cut using a cutting tool or the like as shown in FIG. 3(a). Since the protective layer is also cut at the same time, the protection M around the cutting ridge line is
), the film is torn off, and a Paris-like protrusion occurs at a height of 5 to 10 times the film thickness. When the head base having the Paris-like protrusions is joined to the grooved plate, a gap is created on the orifice surface as shown in FIG. 3(c), and mutual interference occurs between adjacent channels. The ejection characteristics were significantly deteriorated, which was a factor in deteriorating printing quality.

The present invention has been made in view of the above problems, and a main object of the present invention is to provide a liquid jet recording head that has excellent overall durability and high printing quality. Another object of the present invention is to provide a liquid jet recording head that is highly reliable in the manufacturing process and has a high manufacturing yield.

[Means for Solving the Problems] That is, the present invention has a substrate, a heating resistor layer provided on the substrate, and an electrode electrically connected to the heating resistor layer, and has an electric wire that generates thermal energy. In a substrate for a liquid jet recording head comprising a heat converter and a protective layer made of an organic material provided on the electrode, the protective layer made of the organic material is formed inside the ridgeline portion of the substrate. The present invention is a characteristic feature of a liquid jet recording head substrate, and is a liquid jet recording head comprising a liquid path communicating with an ejection port for ejecting liquid, and the head substrate.

The present invention will be specifically described below with reference to the drawings.

FIGS. 1(a), 1(b), and 1(c) show preferred embodiments of the liquid jet recording head of the present invention.

In the liquid jet recording head substrate 102 shown in FIG. 1(a), the second protective layer 112 is formed excluding the area on the cutting line.

The liquid jet recording head 100 shown in the figure includes a substrate 102 for liquid jet recording (bubble jet: abbreviated as BJ) that utilizes heat for liquid ejection, on which a desired number of electrothermal converters 101 are provided, and The main part thereof is constituted by a grooved plate 103 having a desired number of grooves provided corresponding to the heat exchangers 101.

The BJ base 102 and the grooved plate 103 are joined at desired locations with an adhesive or the like, thereby forming the electrothermal converter 1 of the BJ base 102.
A liquid flow path 115 is formed by the portion where 01 is provided and the groove portion of the grooved plate 103, and the liquid flow path 11
5 has a heat acting part 106 as a part of its structure.

The BJ base body 102 includes a substrate 116 made of silicon, glass, ceramics, etc., and a silicon layer on the substrate 116.
A lower layer 109 composed of O□, etc., and a heating resistance layer 110
A common electrode 113 and a selection electrode 114 are disposed along the liquid flow path 115 on both sides of the upper surface of the heat generating resistor layer.
0 parts not covered with electrodes and electrodes 113.1
A first protective layer 111 is provided to cover the portion 14.

The electrothermal converter 101 has a heat generating section 10 as its main part.
7, and the heat generating section 107 is arranged on the substrate 116 in order from the substrate side: a lower layer, a heating resistance layer, a lower layer of the first protective layer made of an inorganic insulating material, and a first protective layer made of an inorganic material. The upper layer of the first protective layer is laminated, and the surface (thermal action surface) of the upper layer of the first protective layer is in direct contact with the liquid filling the liquid flow path.

Almost the majority of the surface of the selection electrode 114 is protected by the second protection J'
1l12 and the first protective layer 111 are laminated in this order from the electrode side, and the upper layer is covered with the bottom surface of the common liquid chamber provided upstream of the liquid flow path +15. provided. The upper layers do not have to be formed in this order, but may be formed in the order of the first protective layer 111 and the second protective layer 112 from the selection electrode side. Alternatively, a second protective layer 112 may be formed as a lower layer of the first protective layer 111 so that the first protective layer N11 in the liquid jet recording head shown in FIG.
The layer formed as the upper layer of 1 may be formed as the third protective layer as the outermost layer. The lower layer of the first protective layer 111 is made of an inorganic insulating material such as an inorganic oxide such as SiO□ or an inorganic nitride such as 5isN4, and the lower layer of the first protective layer 111 is
The upper layer of 1 is sticky, has relatively excellent mechanical strength, and has adhesiveness and adhesion to the lower layer of the first protective layer.
For example, when the lower layer of the first protective layer is made of SiO□, it is made of a metal material such as Ta. In this way, 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 ejected, especially on the heat acting surface 108. The shock from the cavitation action that occurs can be sufficiently absorbed, and the life of the electrothermal converter 101 can be significantly extended. Even if the upper layer of the first protective layer 111 is formed as the third protective layer as described above, the same effect can be obtained.

In the case of the liquid jet recording head 100 shown in FIG. 1, the common electrode is covered only by the first protective layer 111.

As the material constituting the lower layer of the first protective layer 111, an inorganic insulating material with relatively excellent thermal conductivity and heat resistance is suitable. For example, transitions of inorganic oxides such as SiO Metal oxides, metal oxides such as aluminum oxide, calcium oxide, strontium oxide, barium oxide, silicon oxide, and their composites, high-resistance nitrides such as silicon nitride, aluminum nitride, boron nitride, tantalum nitride, etc. Composites of oxides and nitrides, as well as semiconductors such as amorphous silicon and amorphous selenium, may have low resistance in bulk, but can become highly resistive during manufacturing processes such as sputtering, CVD, vapor deposition, gas phase reaction, and liquid coating. Mention may be made of thin film materials that can be made resistive.

In addition to the above-mentioned Ta, materials that can form the upper layer of the first protective layer and the third protective layer include elements of group II a of the periodic table such as Se and Y, Ti, Zr, and Hf. Group ■A elements, V, Group Va elements such as Nb, C
r, Mo.

Group Vla elements such as W, Group II elements such as Fe, Co, Ni, Ti-Ni, Ta-W, Ta-Mo-Ni,
Ni-Cr, Fe-Co, Ti-W.

Fe-Ti, Fe-Ni, Fe-Cr, Fe-N
Alloys of the above metals such as i-Cr; Ti-B, Ta
-B, Hf-B, borides of the above metals such as W-B;
Ti-C, Zr-C, V-C, Ta-C, Mo-C
, 5i-C; carbides of the above metals such as Mo-5i,
Silicides of the above metals such as W-Si and Ta-3i;
Examples include nitrides of the above metals such as Ti-N, Nb-N, and Ta-N. The upper layer of the first protective layer and the third protective layer can be formed using these materials by a method such as a vapor deposition method, a sputtering method, or a CVD method.

The upper layer of the first protective layer and the third protective layer may be the above-mentioned layers alone, but of course some of them can also be combined. Further, the third protective layer is not limited to the above materials alone, but can also be used in combination with the material of the layer below the first protective layer, like the first protective layer shown in FIG.

The second protective layer 112 is made of an organic insulating material that has excellent liquid penetration prevention and liquid resistance properties, and has the following characteristics: (1) good film formability, (2) a dense structure with few pinholes, It is desirable that the material has physical properties such as not swelling or dissolving in the ink used, (1) good insulation properties when formed into a film, and (2) high heat resistance. Examples of such organic materials include the following resins, such as silicone resins, fluororesins, aromatic polybumides, addition-polymerized polybenzimidazoles, metal chelate polymers, titanate esters, epoxy resins, phthalate resins, and thermosetting resins. phenolic resin, p-
Examples include vinyl phenol resin, Zyrotsuta resin, triazine resin, BT resin (triazine resin and bismaleimide addition polymer resin), and the like. In addition, polyxylylene resin and derivatives thereof are deposited to form the second protective layer 112.
can also be formed.

Furthermore, various organic compound monomers such as thiourea,
Thioacetamide, vinylferrocene, 1,3.5-
Trichlorobenzene, chlorobenzene, styrene, ferrocene, viroline, naphthalene, pentamethylbenzene, nitrotoluene, acrylonitrile, diphenylselenide, p-toluidine, p-xylene, N,N-dimethyl-p-toluidine, toluene, aniline, diphenylmercury- Film formation by plasma polymerization using hexamethylbenzene, malononitrile, tetracyanethylene, thiophene, benzeneselenol, tetrafluoroethylene, ethylene, N-nitrosodiphenylamine, acetylene, 1.2.4-trichlorobenzene, propane, etc. The second protective layer 112 can also be formed in this manner.

However, if a recording head like this embodiment 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 112, in addition to the above-mentioned organic materials. is desirable. Specifically, such organic materials include, for example,
Polyimide isoindoquinazolinedione (Product name: P
IQ, manufactured by Hitachi Chemical), polyimide resin (product name: PY
Preferred examples include RALIN (manufactured by DuPont), cyclized polybutadiene (product name: JSR-CBR, CBR-M2O3, manufactured by Japan Synthetic Rubber), Photonease (product name: Toshi), and other photosensitive polyimide resins. It will be done.

The lower layer 109 is provided as a layer that mainly controls the flow of heat generated from the heat generating section 107 toward the substrate 116, and when thermal energy is applied to the liquid in the heat applying section 106, the heat is applied to the liquid. The heat generated from the heat generating section 107 is made to flow more toward the heat acting section 106, and when the electricity to the electrothermal converter 101 is turned off, the heat remaining in the heat generating section is quickly transferred to the substrate side. The selection of constituent materials and the design of their layer thickness are done in a way that flows with the flow. In addition to the above-mentioned 5t(h), examples of the material constituting the lower layer include inorganic materials typified by metal oxides such as zirconium oxide, tantalum oxide, and magnesium oxide.

As the material constituting the heat generating resistor layer 110, 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,
Alternatively, metals such as hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium, vanadium, alloys thereof, and borides thereof are preferred.

Among these materials constituting the heating resistance layer 110, metal borides are particularly excellent, and among them, hafnium boride has the most excellent properties.
This is followed by zirconium boride, lanthanum boride, vanadium boride, and niobium boride.

The heat generating resistor layer 110 can be formed using the above-mentioned materials using techniques such as electron beam evaporation and sputtering.

As the material constituting the electrodes 113 and 114, many commonly used electrode materials can be effectively used, and specific examples include Ajl, Ag, and Au.

Examples include metals such as Pt and Cu, and using these,
It is provided in a predetermined position and with a predetermined size, shape, and thickness by a method such as vapor deposition.

The grooved plate 103 and the materials constituting the common liquid chamber provided on the upstream side of the heat acting section 106 should be such that their shapes are not affected by heat during the working or use environment of the recording head. or is hardly susceptible to micro-precision machining, and
Most of the materials are effective as long as they can easily achieve the desired surface precision and can be processed so that the liquid can flow smoothly through the flow path formed by them.

Typical examples of such materials include ceramics, glass, metals, plastics, and silicon wafers.

Next, in order to improve printing accuracy on the orifice surface of the laminate of the BJ base 102 and the grooved plate 103, an orifice plate 117 with a round hole of high roundness is drilled as shown in FIG.
), an ink-repellent coating layer 119 is applied to the resin or metal thin film 118 provided with the orifice 04 on the side that will become the orifice surface, and an adhesive J@ 120 is applied to the side that will become the bonding surface with the head. It has a layered structure.

Examples of the resin forming the orifice plate include resins with appropriate heat resistance, such as polyimide, polyethersulfone, polysulfone, polyester, acrylic resin, phenolic resin, urea resin, melamine resin, epoxy resin, and silicone resin. It will be done. Further, fillers may be mixed into these resins to increase the strength of the plate.

On the other hand, examples of the metal material include SUS material, nickel, gold, silver, and platinum.

[Example J The substrate for a liquid jet recording head shown in FIG. 1 was manufactured as follows. An Si0g film with a thickness of 5 μm was formed by thermal oxidation of an St wafer and used as a substrate. HfB2 was formed on the substrate as a heating resistance layer to a thickness of 1500 by sputtering, and then a Ti layer of 50A, A/! was formed by electron beam evaporation. layer 500
0. lf.

was deposited continuously.

Next, electrodes 113 and 114 were formed by a photolithography process. The size of the heat-active surface is A4 with a width of 30 mm and a length of 150 μm.
The resistance was 150 ohms including the resistance of the electrodes.

Subsequently, a 5iOz sputtering layer was deposited to a thickness of 2.2 μm as a lower layer of the first protective layer by high-rate sputtering.
Further, as an upper layer of the first bonding RTJH, a Ta layer was deposited to a thickness of 0.5 Im by sputtering Ta.

Next, as a second protective layer, a 2.0 μm thick Photoneese layer was formed on the shaded area in FIG. 1(C) according to the following steps.

That is, the substrate formed into a predetermined pattern in the above process,
After washing and drying, the Photonice solution was coated with a spinner.

Next, it was left at 80° C. for 10 minutes to perform baking. Thereafter, exposure was performed using a mask aligner and development treatment was performed to obtain a desired photonice layer pattern. After washing and drying with isopropyl alcohol, baking was performed at 150° C. for 60 minutes to complete the process of forming the photonice layer pattern.

Next, the substrate was cut and cut using a dicing saw to produce the desired substrate for a liquid jet recording head.

Next, a liquid jet recording head was manufactured using the substrate thus manufactured. First, in order to connect the head base and the wiring board, the head base is bonded to a metal support plate. The wiring board and head base were connected by wire bonding. Next, a grooved plastic plate having grooves of 400 DPI (Dot Per Inch) having the same density as the substrate was bonded and fixed onto the head substrate after alignment.

Furthermore, a multilayer film with an ink-repellent coating layer formed on one side of the 20 μm resin film and an adhesive layer formed on the other side was bonded after aligning an orifice plate with orifices formed by continuous perforation to the grooves. Fixed.

Table 1 shows the results of printing evaluation of the recording head produced in this manner. 1000 heads of each sample were prepared for both the present example and the conventional example.

Table 1 [Effects of the Invention] As is clear from the results in Table 1, the head of the present invention has almost no printing defects, high printing quality, and excellent reliability compared to the conventional head. be. Furthermore, the manufacturing yield is high, and a large quantity of inexpensive heads can be supplied.

[Brief explanation of the drawing]

FIG. 1 shows the structure of the liquid jet recording head of the present invention, (a) is a perspective view of the recording head, (b) is an X-
(C) is a schematic plan view before being divided into head substrates; FIG. 2 shows the configuration of a conventional liquid jet recording head; (a), (b), (c) ) correspond to (a), (b), and (c) in Fig. 1, respectively, and Fig. 3 shows the state of occurrence of burrs due to cutting and division of the conventional head base, and (a) shows the state in which pars occur due to the cutting and division of the conventional head base. (b) is a schematic cross-sectional view after cutting and dividing, and (C) is a schematic cross-sectional view of a liquid recording head using a head substrate which has been cut and divided. 100, 200...liquid jet recording heads 101, 20
1... Electrothermal converter 102, 202... Head base 103, 203... Grooved plate 104, 204... Orifice 105, 205... Groove 106, 206... Heat acting part 07 , 20? ...Heat generating portions 08, 208...Heat action surfaces 09, 209...Lower layer 0.20...Heating resistance layers 1, 21...First protective layer (upper layer) 2, 212・・・
- Second protective layer (upper layer) 3.23... Common electrode 4.24... Selection electrode 5.25... Liquid flow path 6... Substrate 7, 217... Orifice plate 8, 218... Orifice plate base material 9, 219
... Ink-repellent coating layer 20.220 ... Adhesive layer 21 ... Support plate 22 ... Wiring board (b) (C) (C) No. ■ (a) Fig. (a) (b ) (C) Figure

Claims (1)

[Claims] 1. An electrothermal converter that generates thermal energy and includes a substrate, a heating resistance layer provided on the substrate, and an electrode electrically connected to the heating resistance layer; A substrate for a liquid jet recording head comprising a protective layer made of an organic material provided on an electrode, wherein the protective layer made of the organic material is formed inside a ridgeline portion of the substrate. Base for head. 2. A liquid path communicating with a discharge port for discharging liquid; Claim 1
A liquid jet recording head comprising the liquid jet recording head substrate described above.