JPH0551459B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ink jet recording head that performs recording using flying droplets formed by ejecting liquid from an ejection port, and particularly to an ink jet recording head that uses thermal energy. There are various types of liquid jet recording devices, but
Among them, for example, the German Open Gazette (OLS) 2843064
The liquid jet recording apparatus of the type disclosed in US Pat. No. 2,944,005, and US Pat. Since the ejection ports (orifices) for forming flying droplets can be arranged in high density, high resolution can be obtained, and at the same time, the overall recording head can be made more compact. In addition, it has recently been developed because it is suitable for mass production, and it is easy to make it longer by taking full advantage of the advantages of IC technology and micro-processing technology, which have seen remarkable technological progress and improved reliability in the semiconductor field. Their wealth is attracting a lot of attention. The characteristic recording head of the above-mentioned liquid jet recording apparatus is provided with an electrothermal transducer as means for generating thermal energy for ejecting liquid from an orifice to form flying droplets. The electrothermal converter is capable of efficiently applying the generated thermal energy to the liquid, and of reducing the thermal effect on the liquid.
In order to increase the ON-OFF response speed, etc., it is desirable to have a structure in which the heat-acting part is connected to the orifice so as to be in direct contact with the liquid. However, the above-mentioned electrothermal converter basically consists of a heating resistor that generates heat when energized, and a pair of electrodes for energizing the heating resistor. If the exothermic antibody is in direct contact with the liquid, depending on the electrical resistance of the recording liquid, electricity may flow through the liquid, or the liquid itself may be electrolyzed by the flow of electricity through the liquid. Or, when the heating resistor is energized, the heating resistor and liquid react with each other, resulting in a change in resistance value due to corrosion of the heating resistor itself, and even damage or destruction of the heating resistor. Furthermore, the surface of the heating resistor may be damaged or the heating resistor may be damaged due to mechanical shock due to sudden changes in the state of the liquid, preferably including the generation of vapor bubbles, due to the thermal action generated by the heating resistor. Parts of the body may crack or be destroyed. For this reason, in the past, alloys such as NiCr and
The heating resistor is made of an inorganic material that has relatively excellent properties as a heating resistor material, such as metal borides such as ZrB ₂ and HfB ₂ , and SiO ₂ etc. By providing a protective layer (upper layer) made of a material with excellent oxidation resistance, the heating resistor is prevented from coming into direct contact with the liquid, solving the above problems and improving reliability. It has been proposed to improve durability against repeated use. However, a liquid jet recording device having a recording head equipped with an electrothermal converter having the above-mentioned configuration uses a liquid with relatively low electrical conductivity (for example, distilled liquid as a liquid medium) as a colored liquid for recording. When using water or alcohol), it has excellent oxidation resistance and is satisfactory in terms of repeated use durability, but due to the high content of Na ions, etc., the electrical conductivity decreases. When a large recording liquid or electrolyte liquid is used, the durability against repeated use and the resistance to change over time are insufficient. Therefore, there are restrictions on the selection of the recording liquid to be used, which is particularly an obstacle when recording in multiple colors or in natural colors. Furthermore, even when a protective layer is provided on the heating resistor as described above, it has been proven that liquid intrusion toward the heating resistor side is virtually completely prevented due to defects in the protective layer itself that occur during layer formation, for example. It is extremely difficult in terms of performance and mass production. However, in the case of so-called high-density multi-orifice design, in which liquid channels (nozzles) are provided with a large number of high-density heat-acting parts (nozzles), at least as many electrothermal converters as the number of liquid channels are provided. Since it is necessary to provide the protective layer at one time, the influence of defects in the protective layer on the manufacturing yield of the electrothermal converter is a big problem, including the manufacturing cost. Therefore, even if there is no protective layer and the heating resistor is in direct contact with the recording liquid, the liquid resistance and
There is a strong desire to develop a liquid jet recording device equipped with an electrothermal converter that is excellent in repeatability of use, mechanical shock resistance, and electrochemical reaction resistance. The present invention has been made in view of the above points, and its main object is to provide an excellent ink ejecting recording head that solves all of the conventional problems mentioned above. Another object of the present invention is to provide an ink jet recording head that is excellent in liquid resistance, mechanical impact resistance, repeated use characteristics, resistance value stability, and electrochemical reaction resistance. The ink jet recording head of the present invention is provided with a heating resistor layer that forms a heat acting surface that directly applies thermal energy to the ink and generates thermal energy to form bubbles in the ink on the heat acting surface when energized. In an ink jet recording head that performs recording by ejecting ink, the heat generating resistive layer of the electrothermal converter is composed of Sn oxide as a main component and V, Cr, Mn, Fe, and Co. ,Ni,
Cu, Zn, Ga, Zr, Nb, Mo, Ru, Pd, Cd,
It is characterized by being formed using an oxide containing at least one element selected from the group consisting of Sb, Hf, Ta, W, Re, Au, and Bi. The ink jet recording head of the present invention configured as described above has excellent durability against repeated use, liquid resistance, and fidelity and reliability of response to recording signals, and is capable of recording high-resolution, high-quality images at high speed. You can. Furthermore, when the electrothermal transducer is configured so that the heating resistor is in direct contact with the recording liquid, the thermal energy generated by the heating resistor effectively acts on the recording liquid, so that the electric The threshold value of the driving voltage for driving the heat converter is low, and the actual driving voltage for stably forming flying droplets is also low, making it possible to easily realize energy savings. Further, since there is a wide range of recording liquids to choose from, it is possible to easily perform color recording in desired multi-colors and natural colors. Hereinafter, the present invention will be explained in more detail with reference to the drawings. Fig. 1a is a partial front view of the main part of the liquid jet recording device of the present invention as seen from the orifice side, and Fig. 1b
1 is a partial cross-sectional view taken along a portion indicated by a dashed line XY in FIG. 1a. The recording head 1 shown in the figure has a grooved surface 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 substrate 3 on which an electrothermal transducer 2 is provided. It has a structure in which an orifice 5 and a liquid discharge part 6 are formed by joining so as to be covered with a plate 4. Although the liquid jet recording device shown in the figure is shown as having a plurality of orifices 5, the present invention is of course not limited to this, and can also be applied to a recording device with a single orifice. This falls within the scope of the present invention. The liquid discharge section 6 has an orifice 5 at its terminal end for discharging liquid to form flying droplets, and thermal energy generated by the electrothermal converter 2 acting on the liquid to generate vapor bubbles. Thermal action part 7 is a place that causes rapid state changes due to expansion and contraction of its volume.
and has. The heat acting part 7 is located above the heat generating part 8 of the electrothermal converter 2, and has a heat acting surface 9 that contacts the liquid of the heat generating part 8 as its bottom surface. The heat generating section 8 is a lower layer 1 provided on the substrate 3.
0, a heat generating resistor layer (heat generating resistor) 11 provided on the lower layer 10, and an upper layer 12 provided on the heat generating resistor layer 11 as required. The heating resistor layer 11 is provided with electrodes 13 and 14 on its surface for supplying electricity to the layer 11 in order to generate heat. The electrode 13 is an electrode common to the heat generating section of each liquid discharging section, and the electrode 14 is a selection electrode for selectively generating heat in the heat generating section of each liquid discharging section. It is located along the road. The upper layer 12 isolates the heating resistance layer 11 from the liquid in the liquid discharge part 6 in order to chemically and physically protect the heating resistance layer 11 from the liquid used, and also connects the electrodes 13 and 14 through the liquid. The heating resistor layer 11 has a protective function of preventing short circuits. The upper layer 12 has the above-mentioned functions, but since the heat-generating resistance layer 11 in the liquid jet recording device of the present invention has the above-described characteristics, electricity is generated between the electrodes 13 and 14 through the liquid. If there is no risk of short-circuiting, it is not necessarily necessary to provide it, and even if there is the above-mentioned concern, it is not necessary to provide it on the heating resistor layer 11.
Simply covering the surfaces of the electrodes 13 and 14 completely eliminates the above concerns. The lower layer 10 mainly has a heat flow control function.
That is, when forming flying droplets, the heating resistance layer 11
Rather than the heat generated in is conducted toward the board 3 side,
The rate of conduction toward the heat acting part 7 side is increased as much as possible, and after the flying droplets are formed and the power to the clogging heat generating resistor layer 11 is turned off, the heat in the heat acting part 7 and the heat generating part 8 is This is provided so that the liquid in the heat acting section 7 and the generated air bubbles are rapidly cooled by being quickly discharged to the substrate 3 side. By designing the lower layer 10 such that it can fully exhibit the above-mentioned functions in relation to the heat generating resistor layer 11 and the substrate 3, the liquid jet recording device of the present invention becomes more excellent. That is, when forming flying droplets, the heat acting part 7
When the heat flow rate to the side is as large as possible, and the power to the heat generating resistor layer 11 is turned off, the substrate 3
By increasing the ratio of heat flow to the side as much as possible, we can improve the efficiency of droplet ejection energy, high thermal response, and continuous repeatable droplet ejection, improve the droplet formation frequency, and increase the amount of droplets. uniformity, stabilization of droplet flight direction, uniformity of droplet initial flight speed,
Furthermore, it is possible to more effectively improve the fidelity and reliability of responses to recorded signals. As described above, the heat generating resistance layer 11 in the liquid jet recording device of the present invention mainly contains Sn oxide,
In addition, V, Cr, Mn, Fe, Co, Ni, Cu, Zn,
Ga, Zr, Nb, Mo, Ru, Pd, Cd, Sb, Hf,
It is provided as a thin layer doped with an oxide containing at least one element selected from the group of Ta, W, Re, Au, and Bi. In the present invention, the number of oxides to be added is not limited to one type, and two or more types may be mixed in order to obtain the desired characteristics to the maximum. In the present invention, the proportion of the oxide added is preferably 10 mol% or more, more preferably 15 mol%.
As mentioned above, the optimum content is preferably 20 mol% or more. In addition, the Sn oxide which is the main component is preferably
It is desirable that the content be 50 mol% or more. Examples of particularly preferably used additive oxides in the present invention include vanadium oxide (e.g. V ₂ O ₅ ), chromium oxide (e.g. Cr ₂ O ₃ ), cobalt oxide (e.g. CoO), nickel oxide (e.g.
NiO), zirconium oxide (e.g. ZrO ₂ ), antimony oxide (e.g. Sb ₂ O ₃ ), tantalum oxide (e.g. Ta ₂ O ₅ ), tungsten oxide (e.g. WO ₃ ),
Examples include bismuth oxide (eg, Bi ₂ O ₅ ).
Furthermore, chemical stability can be improved by adding two or more types of the above oxides. In the present invention, even if elements other than the above are contained in trace amounts (5 atomic % or less) in the heating resistance layer 11, no deterioration in performance is observed, so there is no problem with the mixing of other elements to this extent. . In the present invention, the content rate of oxygen contained in the oxide is determined depending on the type of partner metal, the content ratio of the partner metals when there are multiple partner metals, etc. in the heating resistance layer that meets the purpose of the present invention. However, from the chemical stability of the surface state and the stability of specific resistance, the amount contained in the film in the entire film constituting the heating resistor layer 11 is It is desirable that the content of oxygen is 70 atomic (at.) % or less based on all atoms. In the present invention, the layer thickness of the heat generating resistor layer 11 is determined based on the characteristics, type and content of the constituent materials, as well as the flying droplet formation characteristics required for the device itself, so that appropriate thermal energy is effectively generated. It can be determined as appropriate depending on the situation, but it is preferably about 500 Å to 10 μ.
Optimally, 2000 Å to 5 μ is desirable. In the present invention, the heating resistance layer 11 made of oxide
is preferably formed by Co-sputtering or electron beam evaporation using a desired oxide target as the main component and additive oxide pellets. Further, it is preferable to form the oxide by a CVD method using a desired metal halide. In the present invention, it is desirable that the resistance value of the oxide be stabilized in advance by a treatment with electricity. Next, an overview of the manufacturing method and form of a liquid jet recording device manufactured in Examples or Comparative Examples of the present invention, which will be described later, will be explained. First, heating resistor installed substrates corresponding to the following Examples and Comparative Examples were prepared in the following manner. Lower layer 1 of alumina substrate 3 that also serves as lower layer 10
After forming the heat generating resistor layer 11 and the aluminum electrode layer on
m, heating resistors 11-1 to 11- with a length of 200 μm
3... was formed. Further, the selection electrode 14 and the common electrode 13 were formed by etching. Furthermore, a protective layer (upper layer) 12 was laminated on the surface of each electrode and each heating resistor, if necessary. Separately from these, a grooved glass plate is formed by cutting a glass plate with multiple grooves (for example, width 40 μm, depth 40 μm) and a groove serving as a common ink chamber (not shown) using a micro cutter. Plate 4 was also created. The heat generating resistor installation board and the grooved plate created in this way are joined after aligning the heat generating resistor and the groove, and liquid ink is supplied from an ink supply section (not shown) to the common ink chamber. An ink introduction tube (not shown) for introducing the ink was also connected to complete the recording device. Further, this recording device was provided with a lead substrate having lead electrodes (a common lead electrode and a selection lead electrode) connected to the selection electrode and common electrode described above. In the liquid jet recording device having the above configuration, if a thin layer of SiO ₂ with a thickness of 1.4μ and a layer of Ta with a thickness of 0.5μ is laminated on each heating resistor layer 11 as the upper layer 12, A drive voltage margin of 1.5 to 1.9 times was obtained. This shows that heat resistance is further improved by providing the upper layer 12 compared to a system in which the heating resistance layer 11 is exposed to the liquid. At this time, the system without the upper layer 12 has a driving voltage margin of about 1.3 times the foaming threshold voltage, which is shown to be superior to the conventional system. As the substrate 3, in addition to the above alumina substrate,
A silicon wafer is used, and as the lower layer 10, layers 2 to 2 are formed by thermally treating the surface of the silicon wafer.
A similar evaluation was performed using a 5μ SiO ₂ layer, and similar good results were obtained. Further, as the substrate 3, in addition to those used in the embodiments, glass, ceramics, heat-resistant plastic, etc. can also be used. In addition to Al, electrode materials include Al-Cu, Al-
Si, etc. can be used, but when using these materials, in order to isolate the electrode and the liquid, for example, a coating made of hardened photosensitive heat-resistant resin is used, excluding the heat-active surface. It is preferred to cover the electrode and the area around the electrode. Example For a liquid jet recording device (sample Nos. 0-1 to 3-3) having the configuration described above (100 liquid channels, one electrothermal converter per one liquid channel), one electrothermal converter was used. Reliability was measured by counting the number of failed electrothermal transducers when pulse driving was performed 5×10 ⁸ times per body. The results are shown in the table below.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1a is a partial front view from the orifice side of a preferred embodiment of a liquid jet recording apparatus to which the present invention is applied, and FIG. 1b is a dashed-dotted line in FIG. 1a.
FIG. 3 is a partial cross-sectional view taken along a section indicated by XY. DESCRIPTION OF SYMBOLS 1... Liquid jet recording device, 2... Electrothermal converter, 3... Substrate, 4... Grooved plate, 5... Orifice, 6... Liquid discharge part, 7... Heat action part, 8... Heat generating part, 9...Heat action surface, 10...Lower layer, 11
...Heating resistance layer, 12... Upper layer, 13... Common electrode, 14... Selective electrode.

Claims (1)

[Scope of Claims] 1. An electrical device comprising a heat-generating resistor layer that forms a heat-active surface that directly applies thermal energy to ink and generates thermal energy to form bubbles in the ink on the heat-active surface when energized. In an ink jet recording head that includes a thermal converter and performs recording by ejecting ink, the heating resistance layer of the electrothermal converter contains Sn oxide as a main component, V, Cr, Mn, Fe, Co, Ni,
Cu, Zn, Ga, Zr, Nb, Mo, Ru, Pd, Cd,
An ink jet recording head characterized in that it is formed using an oxide containing at least one element selected from the group consisting of Sb, Hf, Ta, W, Re, Au, and Bi. 2. The ink jet recording head according to claim 1, wherein the heat acting surface of the electrothermal converter is formed by a protective layer on the heat generating resistance layer. 3 The protective layer is made of Ta that forms the heat acting surface.
3. The ink jet recording head according to claim 2, comprising: a Si insulating layer interposed between the Ta layer and the heating resistance layer. 4. The heat acting surface of the electrothermal converter is formed by the heat generating resistance layer.
The ink-jet recording head described in . 5. The ink jet recording head according to claim 1, wherein the content of oxygen contained in the heat generating resistive layer is 70 atomic % or less. 6. The ink jet recording head according to claim 1, wherein the heat generating resistor layer has a thickness of 500 Å to 10 μm. 7. The ink jet recording head according to claim 6, wherein the heat generating resistor layer has a thickness of 2000 Å to 5 μm.