JPS59124868A - Liquid jet recorder - Google Patents

Abstract

PURPOSE:To enhance liquid resistance, mechanical shock resistance, repeatedly usable property and resistance to electrochemical reaction, by a method wherein a heating resistor layer constituting an electrothermal converting element is formed of an oxide containing a specified element. CONSTITUTION:In the liquid jet recorder 1, the surface of a substrate provided thereon with the electrothermal converting element 2 is jointedly covered by a grooved plate 4 provided with a predetermined number of grooves having a specified width and a specified depth in a predetermined line density, whereby orifices 5 and liquid-ejecting parts 6 are provided. The heating resistor layer 11 is provided in the form of a thin layer of an oxide of Nb, Ir, Pb, Ti, Fe, Re or the like. A particularly preferable example of the metallic oxide is niobium oxide (e.g., Nb2O5) or the like. From the viewpoints of chemical stability of a surface state and stability of specific resistance, the content of oxygen in the layer 11 is preferably not more than 72 atom% of the total atoms in the layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid jet recording device that performs recording using flying droplets formed by discharging liquid from a discharge port, and particularly relates to a liquid jet recording device that uses thermal energy. .

There are various types of liquid injection symbol devices, among which, for example, OLS No. 2843064,
The liquid jet recording apparatus of the type disclosed in USF No. 2944005, USF No. 4335389, etc. can easily perform high-speed color recording, and the recording head, which is the main part of the output section, ejects recording liquid. Since the ejection ports (orifices) for forming flying droplets can be arranged in a high density, high resolution can be obtained, and at the same time, the overall recording head can be made more compact. It is suitable for mass production, and it is easy to make it longer by taking full advantage of the advantages of TC technology and micro processing technology, which have seen remarkable technological progress and improved reliability in the semiconductor field.
Recently, wealth has been attracting a lot of attention.

The characteristic recording head of the liquid jet recording apparatus described above is provided with an electrothermal converter as a means for generating thermal energy for ejecting the i-body from an orifice to form flying droplets. .

The electrothermal converter is connected to an orifice so as to be in direct contact with the liquid in order to efficiently apply the generated thermal energy to the liquid and increase the ON-OFF response speed of the thermal effect on the liquid. It is said that it is desirable to have a structure in which the heat acting part is provided in a heat-acting part.

Both years et al., 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, so it is called a heating resistor. If the body 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 or formed due to the flow of electricity through the liquid. When the heating resistor is energized, the heating resistor reacts with the liquid, resulting in a change in resistance value due to corrosion of the heating resistor itself, damage or destruction of the heating resistor, and even heat generation. Due to the thermal action generated by the resistor, the surface of the heating resistor may be damaged or a portion of the heating resistor may be damaged due to the mechanical shock associated with the sudden change in the state of the liquid, preferably including the generation of vapor bubbles. This may cause cracks to form on the surface and result in destruction.

For this reason, in the past, alloys such as Ni0r and ZrB
The heating resistor is made of an inorganic material that has relatively excellent characteristics as a heating resistor material, such as metal boride such as HfB2, and 5i0
By providing a protective layer (upper M) made of a material with excellent oxidation resistance such as No. It was proposed to try to improve the durability and repeated use durability.

A liquid jet recording device having a recording head equipped with an electrothermal converter configured as described above uses a liquid with relatively low electrical conductivity (for example, a 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 poses an obstacle, especially when performing multicolor or natural color recording.

Furthermore, even when a protective layer is provided on the heating resistor as described above, it has been demonstrated that liquid infiltration 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 fertility and productivity. However, in the case of so-called high-density multi-orifice construction, in which liquid flow channels (nozzles) are provided with a large number of heat-acting parts at high density, it is necessary to use at least as many electrothermal converters as there are liquid flow channels. - Because of the need to provide a protective layer, the impact of failure due to defects in the protective layer on the manufacturing yield of the electrothermal converter is significant, including in terms of manufacturing costs. Therefore, even if there is no protective layer and the heat-generating resistor is in direct contact with the recording liquid, it will have excellent liquid resistance, repeatability, especially resistance value stability, mechanical shock resistance, and electrical resistance. There is a strong desire to develop a liquid jet recording device that includes an electrothermal converter with excellent chemical reactivity.

The present invention has been made in view of the above-mentioned points, and its main object is to provide an excellent liquid jet recording apparatus that solves all of the conventional problems mentioned above.

Another object of the present invention is to provide a liquid jet recording device that is excellent in liquid resistance, mechanical shock resistance, repeated use, and electrochemical reaction resistance.

The liquid jet recording device of the present invention has an ejection port provided for ejecting liquid to form flying droplets, and a discharge port (orifice) that communicates with the ejection port (orifice) to eject liquid to form flying droplets. The heel includes a heat acting part where energy acts on the liquid, and an electrothermal converter as a means for generating the thermal energy, and a heating resistance layer 1b constituting the electrothermal converter.

It is characterized by being made of an oxide containing at least one element selected from the group consisting of Tr, Pb, Ti, Fe, and Rθ.

Since the heat generating resistor layer as described above has a high specific resistance and can be made thick, the resistance to change in resistance value of the heat generating resistor layer over time is improved even if the surface condition changes.

The liquid jet recording device of the present invention configured as described above has the following features:
It has excellent repeatability, liquid resistance, fidelity and reliability of response to recording signals, and can record high-resolution, high-quality images at high speed.

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 one drive voltage for driving the heat converter is low, and the actual drive voltage for stably forming flying droplets is also low, making it possible to easily realize energy savings.

Furthermore, 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. 1(a) is a front view of the main part of the liquid jet recording apparatus of the present invention as seen from the orifice side, and FIG. 1(1)l is the portion indicated by the dashed line XY in FIG. FIG.

The liquid jet recording device 1 shown in the figure has a predetermined number of grooves of a predetermined width and depth 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 the grooved plate 4 so as to cover it. In the case of the liquid jet recording device 1 shown in the figure, a plurality of orifices 5 are overlapped, but the present invention is of course not limited to this, and can be applied to a recording device with a single orifice. This case also falls within the scope of the present invention.

The liquid discharge section 6 has an orifice 5 at its end for discharging the liquid to form flying droplets, and an orifice 5 for discharging the liquid to form flying droplets, and an electrothermal converter 2 for generating unsaturated energy acting on the liquid to generate vapor bubbles. , and has a heat acting part 7 which causes a rapid state change due to expansion and contraction of its volume.

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 includes a lower layer 10 provided on the substrate 3 and a heating resistor layer (heating resistor) 11 provided on the lower layer 10.
, and an upper layer 12 provided on the heating resistance layer 11 as necessary. 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 16 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 provided along the flow path.

The upper part r@12 isolates the heat generating resistor layer 11 from the liquid in the discharge part B in order to chemically and physically protect the heat generating resistor 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 between the two.

The upper layer 12 has the above-mentioned functions, but
The heat generating resistance layer 11 in the liquid jet recording device of the present invention is
Since it has the characteristics described above, the electric fence 13. If there is no risk of an electrical short circuit between the electrodes 13. Just by covering the surface of 14, the above-mentioned concerns are completely eliminated.

The lower layer 10 mainly has a heat flow control function.

That is, when forming flying droplets, the heat generated in the heat generating resistor layer 11 is conducted as much as possible toward the heat acting section 7 side than toward the substrate 6 side. After the flying droplets are formed and the power to the heating resistor layer 11 is turned off, the heat in the heat acting part 7 and the heat generating part 8 is quickly transferred to the substrate 6.
It is provided to rapidly cool the liquid and generated air bubbles in the heat acting part 7 by being discharged to the 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 6, the liquid jet recording device of the present invention becomes even more excellent.

That is, when the flying droplets are formed, the proportion of the heat flow towards the heat acting part Z side is as large as possible, and when the power to the heating resistor layer 11 is turned off, the proportion of the heat flow towards the substrate 6 side is as large as possible. By increasing the heat flow rate as much as possible, we can improve the efficiency of droplet ejection energy, high thermal response, and continuous repeatable droplet ejection, improve the convergence formation frequency, and make the amount of droplets uniform. , 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.

The heat generating resistance layer 11 in the liquid jet recording device of the present invention is
As mentioned above, niobium (N'b), iridium (N'b)
, lead (PI)), titanium (Ti), iron (Fe), and rhenium (Rθ).

In the present invention, the oxide constituting the heat generating resistor layer is not limited to one type, but may be used in combination of two or more types in order to obtain the desired characteristics to the maximum, and the heat generating resistor layer may be composed of two or more layers. A laminated structure may also be used.

In the present invention, specific examples of particularly preferably used metal oxides include niobium oxide (for example, N1) 2
0. ), iridium oxide (e.g. IrO2), lead oxide (
For example, Pl: +O,), titanium oxide (for example, T10),
Examples include iron oxide (eg, Fe50., Fe, O8) and rhenium oxide (eg, Red).

In the present invention, particularly preferred combinations of two types of oxides include niobium oxide-lead oxide, niobium oxide-iridium oxide, iridium oxide-lead oxide, and iridium oxide-iron oxide. Small heating resistance layer 1
Examples of the two-layer structure of No. 1 include rhenium oxide (lower layer), niobium decaoxide (upper layer), iron oxide (lower layer), and titanium decaoxide (upper layer).

In the present invention, the content rate of oxygen contained in the heat generating resistive layer depends on the type of mating metal, the content ratio of the mating metals when there is a plurality of mating metals, etc. The content of oxygen contained in the heat generating resistor layer is determined as desired depending on the chemical stability of the surface state and the stability of specific resistance.
72 atoms relative to all atoms in the layer (hereinafter referred to as % "at0%
(abbreviated as J) is preferred. In addition, when titanium oxide is included, the oxygen content is 40% of all atoms in the layer.
At is preferably 9% or more.

In the present invention, the layer thickness of the heating resistor layer is determined depending on the characteristics, type, content of the constituent materials, and the flying droplet formation characteristics required for the device itself, so that appropriate thermal energy is effectively generated. It is desirable to decide accordingly.

In the present invention, the heat-generating resistance layer made of a metal oxide is formed by snobbing or slatting using a desired oxide target.
Preferably, it is formed by electron beam evaporation using pellets of the desired oxide. Preferably, the oxide is still formed by an OVD method using the desired metal chloride with controlled oxygen content.

In the present invention, it is desirable that the resistance value of the heat-generating resistance layer made of a metal oxide be stabilized by applying electricity in advance.

Next, a general description will be given of nine aspects of manufacturing methods and embodiments of liquid jet recording devices manufactured in Examples or Comparative Examples of the present invention which will be described hereinafter.

First, electrothermal converter installation boards corresponding to the following Examples and Comparative Examples were created using the following nine areas.

After forming the heat generating resistor layer 11 and the aluminum electrode layer on the lower layer 10 of the alumina substrate 6 which also serves as the lower layer 10, selective etching is performed, for example, 1 layer 40 μm, length 200 mm.
Heat generating resistance layers 11-1 to 11-3 of .mu.m were 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 heat generating resistor layer as necessary to form an electrothermal converter on the substrate s.

Apart from these, there is also a grooved plate formed by cutting a glass plate with a plurality of grooves (for example, width 40 μm, depth 40 μm) and a groove serving as a common ink chamber (not shown) using a micro cutter. 4 was also created.

The thus created electrothermal converter installation substrate and grooved plate are bonded together after aligning the electrothermal converter with the grooves, and furthermore, liquid is supplied from an ink supply section (not shown) to the common ink chamber. An ink introduction pipe (not shown) for introducing ink was also connected to complete the recording device.

Furthermore, this recording device was provided with a lead substrate having lead electrodes (a common lead electrode and a selection lead electrode) connected to the aforementioned selection electrode and one common pole.

In the scattering jet recording device having the above configuration, the upper layer 12 has a thickness of 5102 or SiO 1.0 μm.

In the case where a thin layer of Ta with a thickness of 3.5μ is laminated on each heating resistor rfi11, the voltage is 1.5 to 1.
A driving voltage margin of 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.

In addition to the alumina substrate described above, a silicon wafer was used as the substrate 6, and as the lower layer 10, a 2-5 μm SiO□ layer formed by heat-treating the surface of the silicon wafer 9 was used, and similar evaluations were conducted. I did it and got similar good results.

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 At, the electrode materials include At-0u and A4-3.
i, 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.

Embodiment A liquid jet recording apparatus (Sample AO) having the configuration described above
-i~14-1) (100 liquid channels, one electrothermal converter per 81 liquid channels), -! The reliability was measured by counting the number of failed heating resistors when pulse driving was performed 3×10a times per air-thermal converter. The results are shown in Table 1 below.

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[Brief explanation of drawings]

FIG. 1(a) is a partial front view from the orifice side of a preferred embodiment of a liquid jet recording head to which the present invention is applied; Dot-dashed line X
FIG. 2 is a partial cross-sectional view taken along a portion indicated by Y; 1... Liquid jet recording device 2... Electrothermal converter 3... Substrate 4... Grooved plate 5... Orifice 6... Liquid discharge part 7... -Heat acting part 8...Heat generating part 9...Heat acting surface 10...Lower layer 11...Heating resistance layer 12...Upper layer 13...Common electrode 14 ...Selective electrode.

Claims (1)

[Claims] (1) An ejection port provided for ejecting liquid to form flying droplets, and a place communicating with the ejection port where thermal energy acts on the liquid to form flying droplets. and an electrothermal converter as a means for generating the thermal energy, the heating resistance layer constituting the electrothermal converter being a group consisting of Nb, Tr, Pb, Ti, Fe, and Re. A liquid jet recording device comprising an oxide containing at least one element selected from the following.