JPH0465246A - Liquid-jet recorder - Google Patents

Abstract

PURPOSE:To attain an especially easy production of a recorder which is excellent in durability and capable of performing a high density array and a gradation recording, by a method wherein a heat dissipating element is formed so that it had a heat gradient in the direction of the power supply in t he vicinity of a heat releasing resistance layer. CONSTITUTION:A heat dissipating element 16 is composed of a material having a higher thermal conductivity than those of a heat releasing layer and a protective layer 15, and its area which covers the heat releasing element 12 is changed in the direction from a control electrode 13 side to an earth electrode 14 side. By this constitution, a heat gradient in the direction of power supply can be obtained on the heat releasing layer 12 due to the effect of the heat dissipating element 16. As the heat dissipating element 16 is of a plane, its production and construction can be simplified. The position of critical point of bubble generation is shifted in turn by changing the input energy value from larger one to smaller one. Thereby, bubbles 18 are gradually increased in size in the order from a bubble 1 to bubbles 2, 3 and 4, so that the amount of ink is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid jet recording device, and more particularly to a liquid jet recording device that enables gradation recording in an inkjet printer.

Conventional non-impact recording methods have recently attracted attention because the noise generated during recording is so small that it can be ignored. Among them, high-speed recording is possible, and I! The so-called inkjet recording method, which allows recording on plain paper without requiring any special fixing process, is an extremely powerful recording method.

Various methods have been proposed so far, some have been improved and commercialized, and others are still being worked on to put them into practical use.

In this type of inkjet recording method, recording is performed by causing droplets of a recording liquid called ink to fly and adhere to a recording member, and the method of generating the droplets of the recording liquid is The method is roughly divided into several methods depending on the control method for controlling the flying direction of the generated recording liquid droplets.

First, the first method is the one disclosed in U S P3060429 (Tele type method), in which droplets of recording green liquid are generated by electrostatic attraction, and the generated recording liquid droplets are used as a recording signal. Recording is performed by controlling the electric field in accordance with the temperature and selectively depositing recording liquid droplets on the recording member.

To explain this in more detail, an electric field is applied between the nozzle and the accelerating electrode to eject a negatively charged recording liquid droplet from the nozzle, and the ejected recording liquid droplet is converted into a recording signal. Accordingly, the droplet is caused to fly between x and y deflection electrodes configured to be electrically controllable, and the droplet is selectively deposited on the recording member by changing the intensity of the electric field to perform recording.

The second method is described, for example, in USP 3596275, U
The method disclosed in SP 3298030 etc. (5we
et method), in which droplets of recording liquid with a controlled amount of charge are generated by a continuous vibration generation method, and a --like electric field is applied to the generated droplets with a controlled amount of charge. Recording is performed on a recording member by flying between deflection electrodes.

Specifically, the orifice (discharge port) of a nozzle, which is a part of the recording head to which the piezo vibrating element is attached.
A charged electrode configured to have a recording signal applied thereto is arranged at a predetermined distance in front of the piezo vibrating element, and an electric signal of a constant frequency is applied to the piezo vibrating element to mechanically vibrate the piezo vibrating element, A small droplet of recording liquid is ejected from the ejection port. At this time, charges are electrostatically induced in the recording liquid droplet discharged by the charging electrode, and the droplet is charged with an amount of charge corresponding to the recording signal. When a droplet of recording liquid with a controlled amount of charge flies between deflection electrodes to which a constant electric field is uniformly applied, it is deflected according to the amount of charge applied.
Only the droplets carrying the recording signal are allowed to deposit on the recording member.

The third method is, for example, the method disclosed in U.S.P. 3416153 (Hertz method), in which an electric field is applied between a nozzle and a ring-shaped charged electrode, and small droplets of recording liquid are generated by a continuous vibration generation method. This method records by atomizing it. That is, in this method, the atomization state of droplets is controlled by modulating the electric field intensity applied between the nozzle and the charging electrode in accordance with the recording signal, and the gradation of the recorded image is produced.

The fourth method is, for example, the method disclosed in US Pat. No. 3,747,120 (Stemme method), and this method is fundamentally different in principle from the above three methods.

That is, in all three methods, the droplets of recording liquid ejected from the nozzle are electrically controlled while they are in flight, and the droplets carrying the recording signal are selectively attached to the recording member. In contrast, this Stem e method
Recording is performed by ejecting small droplets of recording liquid from an ejection port in response to a recording signal.

In other words, the Steam method applies an electrical recording signal to a piezo vibrating element attached to a recording head that has an ejection port for ejecting recording liquid, and converts this electrical recording signal into mechanical vibration of the piezo vibrating element. In this method, recording is performed by ejecting small droplets of recording liquid from the ejection opening according to the mechanical vibrations and adhering them to the recording member.

These four conventional methods each have their own advantages, but there are also points that can be solved in the other method.

That is, in the first to third methods, the direct energy for generating droplets of the recording liquid is electrical energy, and the deflection control of the droplets is also electric field control.

Therefore, although the first method is simple in structure, it requires a high voltage to generate droplets, and it is difficult to use a multi-nozzle recording head, making it unsuitable for high-speed recording.

The second method allows the recording head to have multiple nozzles and is suitable for high-speed recording, but it has a complicated structure, and the electrical control of recording liquid droplets is sophisticated and difficult, and satellite dots are placed on the recording member. There are problems such as easy occurrence of.

The third method has the advantage of being able to record images with excellent gradation by atomizing small droplets of recording liquid, but on the other hand, it is difficult to control the atomization state and fogging occurs in the recorded image. There are various problems such as the fact that the recording head is difficult to form a multi-nozzle recording head, and is therefore unsuitable for high-speed recording.

The fourth method has relatively many advantages compared to the first to third methods. In other words, the configuration is simple, and in order to perform recording by ejecting the recording liquid from the ejection port of the nozzle on-demand (on-dei+and), the method of ejecting flying small droplets as in the first to third methods is effective. Second, it is not necessary to collect droplets that are not needed to record an image, and unlike the first and second methods, there is no need to use a conductive recording liquid, and the material of the recording liquid is However, on the other hand, there are problems in processing the recording head, and it is extremely difficult to miniaturize a piezo vibrating element having a desired resonance number. For these reasons, it is difficult to create a multi-nozzle recording head, and because recording liquid droplets are ejected and ejected using mechanical energy from the mechanical vibration of the piezoelectric vibrating element, it is not suitable for high-speed recording. have

As described above, conventional liquid jet recording methods have advantages and disadvantages in terms of structure, high-speed recording, multi-nozzle recording heads, generation of satellite dots, and fogging of recorded images. There was a restriction that it could only be applied to uses that benefit the public.

However, this inconvenience can be almost eliminated by adopting the inkjet recording method previously proposed by the applicant. The details of this inkjet recording method are explained in Japanese Patent Publication No. 56-9429.
To summarize it here, the ink in the liquid chamber is heated to generate bubbles, which causes a pressure increase in the ink, and the ink is ejected from a fine capillary nozzle to record. Since then, many inventions have been made using this principle. As one of them, for example,
There is a publication No. 943. This is characterized by applying a signal with gradation information to an electrothermal transducer equipped with a heat generating part having a heat generating amount adjustment structure, and performing gradation recording by causing the heat generating part to generate an amount of heat according to the signal. It was intended to be. Specifically, the structure is such that the thickness of the protective layer, the heat storage layer, or the heat generating layer gradually changes, or the pattern width of the heat generating layer gradually changes.

Figures 24 to 26 are respectively
This is a cross-sectional structural diagram showing an example of the electrothermal converter disclosed in FIGS. 4 to 6 of the 1943 publication, and in the figure, 71 is a substrate;
2 is a heat storage layer, 73 is a heating element 574, 75 is an electrode, and 76 is a protective film. In the example shown in FIG.
By providing a thickness gradient from the 4th side toward the electrode 75.

A gradient is provided in the amount of heat generated per unit time from the surface of the heat generating portion ΔΩ to the liquid that is in contact with the surface.

Further, in the example shown in FIG. 25, the thickness of the accumulation layer 72 is gradually decreased from A to B in the heat generating part ΔΩ,
A distribution is given to the amount of heat generated by the heating element 73 that is radiated to the substrate 71, and a gradient is provided in the amount of heat per unit time given to the liquid that is in contact with the surface of the heating portion ΔQ.

In addition, in the example shown in FIG. 26, the thickness of the heating element 73 is formed on the accumulation layer 72 by providing a gradient in the thickness of the heating element 73 at the heating part ΔQ, and each part from A to B is formed on the accumulation layer 72. The amount of heat generated per unit time is controlled by changes in resistance at a location.

In addition, Figures 27 to 31 are respectively
27 is a plan view showing an example of the electrothermal converter disclosed in FIG. 9 to FIG. 13 of Publication No. 9-31943. An example is
The planar shape of the heat generating part 81 is rectangular, and the electrode 82 and the heat generating part 8
The connection part between the electrode 83 and the heat generating part 81 is made smaller than the connection part between the electrode 83 and the heat generating part 81. In the examples shown in FIGS. 28 and 29, the central portion of the heat generating portion 81 has a planar shape that is thinner than both ends. Furthermore, the example shown in Fig. 30 is
The planar shape of the heat generating part 81 is a trapezoid, and electrodes 82 and 83 are connected to opposite sides of the trapezoid, which are not parallel, as shown in the figure.

In addition, in the example shown in FIG. 31, the central part of the heat generating part 81 is made wider than both ends, and these examples give a negative gradient to the current density from A to B of one heat generating part. By configuring it differently and varying the applied power level,
The size of the ejected droplets is changed by controlling the abrupt change in the state of the liquid that occurs in the heat-acting part, thereby performing gradation recording.

However, it is virtually impossible to form three-dimensional structures such as the examples shown in Figs. 24 to 26 using thin film formation technology, and even if it were possible, the cost would be extremely high. It has the disadvantage of being Also, Figures 27 to 3
When the pattern width was changed as shown in Figure 1, wire breakage was likely to occur where the pattern was narrowest, and good results were not necessarily obtained in terms of durability.

On the other hand, Japanese Patent Laid-Open No. 63-42872 also discloses a similar gradation recording technique. Similar to the technique disclosed in Japanese Patent Publication No. 59-31943, this technique is also characterized in that the heating layer has a three-dimensional structure, and has the disadvantage that it is extremely difficult to manufacture. As other gradation recording technology
Japanese Patent Publication No. 2-46358, Japanese Patent Publication No. 62-46359, and Japanese Patent Publication No. 62-48585 are known. They select a predetermined number of heating elements from a plurality of heating elements arranged in one flow path, or select one heating element from a plurality of heating elements with different calorific values to suppress the generated bubbles. The discharge amount was changed by changing the size or by variably controlling the input timing of drive signals to the plurality of heat generating elements.

However, in these technologies, multiple heating elements are
Since the number of control electrodes connected to the plurality of heating elements increases, it has been impossible to arrange the discharge ports at a high density. Also, JP-A-59-124863, JP-A-59-12486
Publication No. 4 discloses a technology for controlling the discharge amount by having a heating element separate from the heating element for discharging and a bubble generating section, but these also have difficulty in high-density arrangement due to the presence of the bubble generating section. It has the disadvantage of being Furthermore, JP-A-63-42
Japanese Patent Application No. 869 discloses a technique for controlling the discharge amount by changing the number of times bubbles are generated by changing the time during which the resistor is energized. However, in a normal bubble jet, the energizing time is limited to several to tens of microseconds, and if the energizing element is energized for longer than that, the heating element will be disconnected. This is not possible.

As described above, various attempts have been made in the prior art to perform single-gradation recording, but satisfactory results have not always been obtained from the viewpoint of manufacturing, durability, or high-density arrangement. do not have.

The present invention was made in view of the above-mentioned circumstances.
The purpose of this invention is to provide a liquid jet recording device that is particularly easy to manufacture, has excellent durability, is capable of high-density arrangement, and is capable of gradation recording.

! -1 In order to achieve the above object, the present invention includes an ejection port for ejecting a liquid to form flying droplets, and a state change caused by heat in the liquid in order to eject the liquid. In a liquid jet recording device comprising a liquid jet recording head having a heat generating resistor layer for heating and a pair of electrodes electrically connected to the heat generating resistor layer, the current flow direction is set in the vicinity of the heat generating resistor layer. A heat dissipation structure is formed so as to have a thermal gradient, and the heat dissipation structure includes a layer that is in contact with the heat dissipation structure above or below the heat dissipation structure in the vicinity of the heating resistor layer. It is characterized in that it is made of a material with a thermal conductivity higher than that of the constituent materials, and that the input energy is made variable in accordance with one image information. Below 1
An explanation will be given based on an example of the present invention.

FIG. 18 is a diagram for explaining the operation of a bubble jet head as an example of an ink jet head to which the present invention is applied, FIG. 19 is a perspective view showing an example of a bubble jet head, and FIG. 20 is a diagram for explaining the operation of a bubble jet head as an example of an ink jet head to which the present invention is applied.

The lid substrate that constitutes the head shown in Fig. 19 (Fig. 20 (
FIG. 21 is a perspective view of the lid substrate shown in FIG. 20(a) seen from the back side.

In the figure, 21 is a lid substrate, 22 is a heating element substrate, 23 is a recording liquid inlet, 24 is an orifice, 25 is a flow path, 26 is a region for forming a liquid chamber, 27 is an individual (independent) electrode, 28
is a common electrode, 29 is a heating element (heater), 30 is ink,
Reference numeral 31 indicates a bubble, and reference numeral 32 indicates a flying ink droplet.The present invention is applied to such a bubble jet type liquid jet recording head.

First, ink jetting by a bubble jet will be described with reference to FIG. 18. (a) is a steady state, in which the surface tension of the ink 30 and the external pressure are in equilibrium on the orifice surface.

In (b), the heater 29 is heated until the surface temperature of the heater 29 rises rapidly and boiling development occurs in the adjacent ink layer, and microbubbles 31 are scattered.

(c) shows a state in which the adjacent ink layer that is rapidly heated on the entire surface of the heater 29 is instantaneously vaporized to form a boiling film, and the bubbles 31 grow. At this time, the pressure inside the nozzle increases by the amount of bubble growth, and the balance with the external pressure on the orifice surface is lost, causing an ink column to begin to grow from the orifice.

(d) shows a state in which the bubble has grown to its maximum, and ink 30 corresponding to the volume of the bubble is pushed out from the orifice surface. At this time, no current is flowing through the heater 29, and the surface temperature of the heater 29 is decreasing. The maximum value of the volume of the bubble 31 is slightly delayed from the timing of electric pulse application.

(e) shows a state in which the bubbles 31 are cooled by ink or the like and begin to contract. At the tip of the ink column, it moves forward while maintaining the extruded speed, and at the rear end, the ink flows backward from the orifice surface into the nozzle due to the decrease in nozzle internal pressure as the bubbles contract, creating a constriction in the ink column. .

In (f), the air bubbles 31 are further contracted, the ink comes into contact with the heater surface, and the heater surface is cooled even more rapidly. At the orifice surface, the external pressure is higher than the nozzle internal pressure, so the meniscus is largely moving into the nozzle. The tip of the ink column becomes a droplet and drops 5 to 1 droplets toward the recording paper.
It is flying at a speed of 0m/sec.

In (g), the air bubbles have completely disappeared in the process of refilling the orifice with ink by capillary action and returning to the state of (a).

FIG. 22 is a diagram showing a typical example for explaining the main part configuration of the liquid jet recording head as described above, and FIG. 22(a)
22(b) is a detailed front partial view of the bubble jet recording head as seen from the orifice side, and FIG. It is.

The recording head 41 shown in these figures has a predetermined number of grooves of a predetermined width and depth at a predetermined linear density on a substrate 43 on which an electrothermal transducer 42 is provided on the back surface. By bonding the grooved plate 44 so as to cover the substrate 43, a liquid discharge portion 46 including an orifice 45 for ejecting liquid is formed. Liquid discharge part 46
has an orifice 45 and a heat acting part 47 where thermal energy generated by the electrothermal converter 42 acts on the liquid to generate bubbles and cause rapid changes in state due to expansion and contraction of the volume.

The heat acting part 47 is located above the heat generating part 48 of the electrothermal converter 42, and has a heat acting surface 49, which is a surface of the heat generating part 48 that comes into contact with the liquid, as its lower surface. The heat generating section 48 is
It is composed of a lower layer 50 provided on the base 43, a heating resistance layer 51 provided on the lower layer 50, and an upper layer 52 provided on the heating resistance layer 51.

The heating resistance layer 51 is provided with electrodes 53 and 54 on its surface for supplying electricity to the core layer 51 in order to generate heat, and the heating resistance layer between these electrodes allows the heat generating portion 4
8 is formed.

The electrode 53 is an electrode common to the heat generating section of each liquid discharging section, and the electrode 54 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 protective layer 52 is a heat generating resistor layer 51 in the heat generating section 48.
In order to chemically and physically protect the liquid from the liquid used, the heating resistor layer 51 and the liquid filling the liquid flow path of the liquid discharge part 46 are separated, and the electrodes 53 and 54 are connected through the liquid.
It has the role of preventing short circuits between adjacent electrodes and further preventing electrical leakage between adjacent electrodes.

The liquid flow paths provided in each liquid discharge portion are communicated with each other via a common liquid chamber (not shown) that constitutes a part of the liquid flow path upstream of each liquid discharge ridge portion. Due to design considerations, the electrodes 53 and 54 connected to the electrothermal converter 42 provided in each liquid discharge section are protected by the upper layer and are connected to the bottom of the common liquid chamber on the upstream side of the heat acting section. It is set up to pass through.

FIG. 23 is a detailed diagram for explaining the structure of a bubble generating means using a heating resistor, in which 61 is a heating resistor;
Reference numeral 2 indicates an electrode, 63 a protective layer, and 64 a power supply device. 1 Useful materials for forming the heating resistor 61 include, for example, a tantalum-3iO□ mixture, tantalum nitride,
Nichrome, silver-palladium alloy, silicon semiconductor, or hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium,
Examples include borides of metals such as vanadium.

Among the materials constituting these heating resistors 61, metal borides are 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 heating resistor 61 can be formed using the above-mentioned materials using techniques such as electron beam evaporation and sputtering. The film thickness of the heating resistor 61 is determined by its area, material, and shape and size of the heat-acting portion so that the amount of heat generated per unit time is as desired.

Furthermore, it is determined according to actual power consumption, etc., but in normal cases, it is 0.001 to 5 μm, preferably 0.
．． 01 to 1 μm.

As the material constituting the electrode 62, many commonly used electrode materials can be effectively used, and specifically,
For example, AQ, Ag, Au, Pt.

Examples include Cu, and these are used to provide a predetermined size, shape, and thickness at a predetermined position by a method such as vapor deposition.

The characteristics required of the protective layer 63 are to protect the heat generating resistor 61 from the recording liquid without preventing the heat generated by the heat generating resistor 61 from being effectively transferred to the recording liquid. Examples of useful materials for forming the protective layer 63 include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, and zirconium oxide. It can be formed by The thickness of the protective layer 63 is usually 0.01 to 10 μm, preferably 0.1 to 5 μm, and most preferably 0.1 to 3 μm.

In the bubble jet technology having the above-mentioned principle or heating element structure, the present invention provides an ejection port for ejecting liquid to form flying droplets, and an ejection port for ejecting liquid to form flying droplets, and for causing a state change in the liquid due to heat. In a liquid jet recording apparatus equipped with a liquid jet recording head having a heat generating resistor layer for ejecting liquid and a pair of electrodes electrically connected to the heat generating resistor layer, A heat dissipation structure is formed in the vicinity so as to have a thermal gradient in the direction of current flow, and the heat dissipation structure is present above or below the heat dissipation structure in the vicinity of the heating resistor layer in contact with the heat dissipation structure. It is characterized by being made of a material with a thermal conductivity higher than that of the material constituting the layers, and having variable input energy depending on image information.

FIG. 1 is a configuration diagram of the main part (heating element part) of a bubble jet liquid jet recording apparatus according to the present invention, and FIG. 2 is a configuration diagram of the heating element part of a bubble jet liquid jet recording apparatus that does not perform normal gradation recording. In the figure, (a) is a plan view, and (b) is a (
, ) is a cross-sectional view taken along the line B-B of the figure. In the figure, 10 is the substrate, 1
1 is a heat storage layer, 12 is a heat generating layer, 13 is a control electrode, 14 is a ground electrode, 15 is a protective layer, 16 is a heat sink, and 17 is an insulating layer. In the present invention, as shown in FIG. A heat sink 16 is provided on the heat generating layer 12. This heat sink 16
is made of a material with higher thermal conductivity than both the material constituting the heat generating layer 12 sandwiching it and the material constituting the protective layer 15, and is not provided uniformly over the entire surface of the first heat generating layer 12. As shown in FIG. 1, the area covering one heating element layer 12 changes from the control electrode 13 side to the ground electrode 14 side. By doing this.

On the heating element layer, it is possible to create a thermal gradient in the direction of current flow due to the effect of the heat radiating element.

In the present invention, since the heat sink is formed in a planar (two-dimensional) manner as described above, there is an advantage that it can be easily and simply manufactured in terms of manufacturing or structure. As mentioned above, the material constituting the heat dissipating body must be a material with higher thermal conductivity than the materials constituting the heat generating layer and the protective layer, and it must be a material that has a higher thermal conductivity than the materials constituting the heat dissipating layer and the protective layer, and must be thin film formed by vapor deposition, sputtering, etc., and microfabricated by photoetching, etc. It is preferable that the material is a material that can be easily formed, and examples of such materials include gold, silver, copper, aluminum, tungsten, chromium, germanium, platinum, tantalum, titanium, etc.
The present invention is not particularly limited to these. In addition,
In the case of FIG. 1, the heat sink 16 is formed in direct contact with the heat generating layer, but the pattern of the heat sink 16 is different from the earth electrode 14 so that the heat sink 16 does not function as a ground electrode. Appropriate insulation treatment 17 is performed without contacting with. In the present invention, for a head having such a thermal gradient on the heat generating layer, the input energy to the heat generating layer is changed in accordance with two pieces of image information. Generally, in the bubble jet technology, when bubbles are generated on the heating element layer by a film boiling phenomenon, the surface temperature on the heating element layer must instantaneously rise to a certain temperature or higher.

In other words, in order for film boiling to occur, it is necessary for the temperature to exceed a certain critical temperature, but if a region that reaches that critical temperature is formed at any position on the heating element layer, the size of the generated bubbles will increase. This means that it can be changed arbitrarily. Figure 3 shows the principle.

FIG. 3 shows the generated bubbles in the cross section of FIG. 1 with dotted lines. As described above, in the present invention, the heat radiator 16 provided on the heat generating layer 12 creates a thermal gradient on the heat generating layer with respect to the current supply direction.

Therefore, by changing the input energy from a small value to a large value, the position of the critical point of bubble generation due to film boiling is sequentially moved in accordance with the thermal gradient. As a result, as shown by the dotted line in Figure 3, from small bubbles 1 to 2 and 3,
．． The size of the bubble 18 increases to 4.

FIG. 4 shows the relationship between the input energy and the size of the generated bubbles, and FIG. 5 shows the relationship between the generated bubbles and the amount of ink ejected. The input energy is pulse voltage,
Although either pulse width may be changed, it is desirable to change the pulse voltage in order to instantaneously generate bubbles using the film boiling phenomenon. However, the pulse width is also up to 30 μS.
As long as it is changed within a range of about eC, there is no problem in practice.

FIG. 6 is a diagram for explaining another embodiment of the present invention, in which the heat sink 16 is formed under the heat generating layer 12 with an insulating layer 17 interposed therebetween.

Therefore, the heat sink 16 is made of a material that has higher thermal conductivity than both the material that makes up the insulating layer 17 and the material that makes up the heat storage layer 11 . Generally, the thermal conductivity of the material constituting the heat storage layer 11 or the material constituting the insulating layer 17 is about the same or lower than the thermal conductivity of the material constituting the protective layer 15. The materials for the heat sink mentioned in the embodiment shown in FIG. 1 are also suitable for this embodiment. Furthermore, the insulating layer 17 is sufficiently thick so that the amount of heat transmitted to the heat generating layer 12 is small, and the thermal conductivity of the material constituting the heat storage layer 11 and the material constituting the AM layer 17 is such that the heat of the material constituting the heat generating layer 12 is small. If the conductivity is lower than the conductivity, the material constituting the heating resistor 61 explained in FIG. A material having a thermal conductivity of

FIG. 7 shows yet another embodiment, in which a heat sink 16 made of a material with higher thermal conductivity than the material constituting the protective layer 15 is formed on the protective layer 15. . In this case as well, the material constituting the heat sink 16 is first
The material of the heat dissipation body mentioned in the example shown in the figure is suitable, but the thermal conductivity of the material constituting the protective layer 15 is
If the thermal conductivity is lower than that of the material constituting the heat sink 16, the material constituting the heating resistor 61 explained in FIG. A wide range of materials having thermal conductivity comparable to those of these materials can be used as the material constituting the heat sink 16.

FIGS. 8 and 9 show modified examples of the pattern of the heat sink 16. The pattern shown in FIG. 8 is advantageous because it reduces the cost when manufacturing a photomask.

On the other hand, when heat radiators are formed on both sides as shown in FIG. 9, there is an advantage that the symmetry of generated bubbles is improved and stabilized.

Although the embodiments of the present invention have been briefly explained above,
Some explanations have been omitted to avoid complicating the diagram. For example, Figures 1 and 2.

In the cross-sectional views of Figures 3, 6, and 7 (Figure (b)), the electrodes are exposed, but this is because they are covered with a suitable protective film (
It is preferable to prevent direct contact with the ink using polyimide, etc.). Similarly, for the heat sink, if a material that is corroded by ink (eg AQ) is used, a protective film should be provided. Also, the first
Figure, Figure 2.

In the plan views ((a)) of Figures 6, 7, and 10, as well as Figures 8 and 9, the protective film on the heating element layer is omitted, but this also complicates the illustrations. This is to avoid this, and in reality, a protective film exists.

Next, a specific method for manufacturing the liquid jet recording head shown in FIG. 1 will be described. First, a silicon wafer is thermally oxidized to grow a 2 μm thick Si film on the surface to form the heat storage layer 12 . Next, as the heating element layer 13, 2 HfB2
Sputtering for 200 people. Next, as the heat dissipation body 16, 10,000 AQ was vapor-deposited, and the electrodes 13 and 14 were
As a result, 8,000 people deposited Au. At this time, the heat sink AΩ
Si is used as the insulating layer 17 to prevent contact between the
Form O2. Next, Sio2 was sputtered by 9000 people as a protective film 15 for the heat generating layer. Furthermore, 3000% Ta is added as an anti-cavitation layer on top of it.
People sputtered. During the formation of each of these films, well-known photolithography and photoetching techniques are used, and the final pattern of the heating element is a rectangle of 24 .mu.m.times.80 .mu.m. Note that the electrode width is 24 μm in the short direction of one heating element pattern.

FIG. 10 is another embodiment of the invention. Therefore, the first
In the embodiment shown in the figure, the heat sink 16 is connected to the ground electrode 1
In the embodiment shown in FIG. 10, there is no SiO2 insulating layer, and the heat sink 16 is in contact with the ground electrode 14. Therefore, the heat sink 16 also plays the role of a ground electrode. In other words, the heat generating part of the heat generating layer is not rectangular, but the part that is not covered by the heat sink in FIG. 10, that is, the right angle in FIG. It has a triangular shape, and the heat generating layer itself has a thermal gradient. In this case, both the thermal gradient of the heat sink and the thermal gradient of the heat generating layer come into play. In this case, the material constituting the electrode 62 shown in FIG. 23 can be used as the material for the heat sink and earth electrode.

In addition, in the explanation of the manufacturing method in the case of Figure 1, it was shown that the heat sink and the electrode (earth electrode) were manufactured separately, but the
In the case of Figure 0, they may be manufactured simultaneously (integrated).

FIG. 11 shows yet another embodiment, for example 16
In order to enable a higher density arrangement than this, the present invention is applied to a heating element substrate with an electrode laminated structure to form a heat sink. A method for manufacturing a heating element substrate having an electrode laminated structure will be briefly described.

FIG. 12 is a sectional view for explaining one embodiment of the present invention, in which 10 is a substrate, 12 is a heating resistor layer, 13 is a first electrode, 14 is a second electrode, and 15 is a A protective layer (ink-resistant), 17 is an insulating layer, part A of the first electrode 13 is a part from which a lead wire is taken out, and B is a part to which a heating resistor is connected.

13(a) to (e) are diagrams showing the procedure for obtaining the configuration shown in FIG. 12. First, the first electrode 13 is formed on the substrate 10 (see FIG. 13). a))+ On this electrode 13, except for at least a portion A from which a lead wire is taken out and a portion B to which a heating resistor layer 12 (described later) is connected,
An insulating layer 17 is provided (FIG. 13(b)), then a heating resistor layer 12 is provided (FIG. 13(c)), and then.

The second electrode 14 is the first electrode 13 of the heating resistor layer 12.
(FIG. 13(d)). Finally, a protective film 15 is formed to protect the heating resistor layer 12 from ink, and the process is completed (FIG. 13(e)). In addition to this, an electrode protective layer or an anti-cavitation protective film is also provided if necessary, but the explanation is omitted here for the sake of brevity. FIG. 11 is a plan configuration diagram showing an example in which a heat dissipation body 16 of the present invention is provided to a heat dissipation body substrate having an electrode laminated structure manufactured by the above-described process.

Figures 14(a) to (g) are diagrams showing the manufacturing process of the heating element substrate of the present invention, and Figure 15 is an AA cross-sectional view of the heating element substrate completed in Figure 14(g). Yes (Configuration 5
). In the figure, 91 is a heating element (HfB2), 92 is a first electrode (AQ), 93 is an insulating layer (Sun), 94 is a second electrode (AQ), 95 is a thermal insulation layer (Sio2), 96
97 is an anti-cavitation layer (Ta), and 97 is an electrode protective layer (
(Photonice), 98 is a bonding pad. The shaded area is the pattern formed in each step.

(a) S with a Sio2 film formed on the surface by thermal oxidation etc.
A heating element 91 is formed on the i-wafer. Here, HfB2 was formed by 3000 person sputtering as a heating element material. (b) 100% AQ92 as the first electrode
It was formed by sputtering. (C) As the insulating layer 93, Sio2 was formed by sputtering with 8,000 people. Note that when forming this pattern, an insulating layer is not attached to a portion connected to a second electrode, which will be described later, and a bonding pad portion. (d) Second
AQ 94 was formed as an electrode by 10,000 sputtering. This second electrode also serves as a heat dissipation structure, and as is clear from the figure, the area it occupies is continuous so that there is a thermal gradient due to heat dissipation in the current direction in the part above the heating element through the insulating layer. It has changed to In addition,
AQ is excellent as an electrode material and has good thermal conductivity, making it one of the most suitable materials for heat dissipation structures. (e
) Next, a thermal insulating layer 95 of 5 in 2 was formed by sputtering with 5,000 people. This is to thermally separate the anti-cavitation layer, which will be described later, and the heat dissipation structure described above, so that the heat dissipation structure can better perform its function.

(f) 3000% Ta as anti-cavitation layer 96
Formed by manual sputtering. This is to absorb the physical impact force when the generated bubbles disappear, protect the first heating element from damage, and extend its life. (
g) Photoneese (Toshiku Co., Ltd.) as the electrode protective layer 97
12,000 people were formed.

16(a) to 16(g) are diagrams showing other embodiments of the manufacturing process of the heating element substrate of the present invention, and FIG. 17 shows the B- It is a sectional view of B (corresponding to configuration 6). In the figure, 101 is the first electrode (AQ)
, 102 is an insulating layer (Sin), 103 is a heating element (H
fB, ), 104 is the second electrode (Afi), 105 is the heating element protective layer (SxOz), 106 is the anti-cavitation layer (Ta), 107 is the electrode protective layer (Photonice), 10
8 is a pounding pad. The shaded area is the pattern formed in each step. (a) Si on the surface by thermal oxidation etc.
n. AQ was formed as a first electrode 101 on the Si wafer on which the film was formed by sputtering with 10,000 people.

This first electrode also serves as a heat dissipation structure, and as is clear from Figure 1, the pattern of the portion where the heating element is laminated via the insulating layer, which will be described later, is in the direction of current flow of the heating element. The area it occupies changes continuously, creating a thermal gradient due to heat radiation. (b) As the insulating layer 102, 5i
n2 was formed by 8000 person sputtering. Note that when forming this pattern, an insulating layer is not applied to a portion connected to a second electrode and a bonding pad portion, which will be described later.

(c) As the heating element 103, HfB2 was formed by 3000 person sputtering. (d) Second electrode 104
AQ was formed by sputtering with 10,000 people. (e) Next, a 5 in 2 layer was formed as a heating element protective layer 105 by sputtering with 10,000 people. This is mainly to prevent the heating element from being chemically corroded by the ink, and is formed to reduce defects such as pinholes.

In other words, the film thickness is formed to be as thick as possible. On the other hand, from the standpoint of heat transfer efficiency to the ink or thermal stress, it is desirable that the thickness be as thin as possible, and in the present invention, 10,000 is used as the optimum value. (f
) Ta was formed as the anti-cavitation layer 106 by sputtering using 3,000 sputtering methods. This is to absorb the physical impact force when the generated bubbles disappear, protect the heating element from damage, and extend its life. (g
) 12,000 layers of Photonice (manufactured by Toshiku Co., Ltd.) were formed as the electrode protective layer 107. Although the explanation was omitted,
In each of the embodiments of Structure 5 and Structure 6 explained in FIGS. 14 to 17 above, the pattern is formed by forming each layer by sputtering, and then using positive photoresist 0FPR (manufactured by Tokyo Ohka Co., Ltd.). Each pattern was formed by photolithography and etching.

The heating element substrate according to the present invention formed in this way is coated with a polyimide electrode protective layer as described above, if necessary.
The thickness is 5 to 5 μm. The lid substrate shown in FIG. 20(a) is bonded to the heating element substrate of the present invention thus produced to complete the head.

By using this head and varying the input pulse voltage from 18 to 40V, the bubble size (the length of the bubbles on the heating element pattern) could be varied from 15 to 110 μm, and the amount of ejected ink could be changed accordingly. The pixel diameter on the paper surface could be changed from 50 μm to 120 μm. Note that the pulse width at this time is 6 μsec.

- Since the heat sink can be formed in a flat plane using thin film formation technology, photolithography technology, photoetching technology, etc., manufacturing is easy and can be performed with high precision.

- Since the thermal conductivity of the heat dissipating body is higher than that of the layers sandwiching it, it is possible to easily create a thermal gradient on the heat acting surface where the heat generating part contacts the liquid.

In order to verify the effects of the present invention, in addition to the above-mentioned examples, the following two examples and a comparative example were prototyped and discharge experiments were conducted.

Thick back ↓ Structure: Material and thickness of the same layer as in Figure 1: Heat sink 16...A fl (10
000 people) heating element layer 12-=TaSiO,, (3000
(people) Protective layer 15...Sio, (10,000 people) Results: A thermal gradient was created in the thermal energy application area, the size of the bubbles changed depending on the input energy, and the amount of ejected ink could also be changed.

DaijMJf! L4 Structure: Same layer material and thickness as in Figure 1: Heat sink 16...A Q (100
00 people) Heating layer 12-Ta2N (2500 people) Protective layer 15...S 1o2 (10000 people) Result: A thermal gradient is created at the thermal energy acting part, the size of bubbles changes depending on the input energy, and discharge I was also able to change the amount of ink.

However, structure: Material and thickness of the same layer as in Figure 1: Heat sink 16...S i O2 (8
000 people) Heating layer 12-TaSi○2 (3000 people)
Protective layer 15-S 1o2 (10,000 people) Results: No thermal gradient was formed in the thermal energy application area, and no effect of the heat sink was observed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a heat generating section of a bubble jet liquid jet recording apparatus according to the present invention, and FIG. Fig. 3 is a diagram for explaining the principle of changing the size of bubble generation, and Fig. 4 is a diagram showing input energy and bubble generation. FIG. 5 is a diagram showing the relationship between the size of bubbles and the amount of output ink, and FIGS.
The figures show other embodiments of the invention, FIGS. 8 and 9 show modified examples of the heat sink pattern, and FIG. 10 explains another embodiment of the invention. FIGS. 11 to 13 are diagrams for further explaining other embodiments of the present invention, and FIGS. 14 and 15 are diagrams illustrating the manufacturing process of the heating element substrate of the present invention. Figure 16 and 1
FIG. 7 is a diagram showing another embodiment of the manufacturing process of the heat generating substrate of the present invention, and FIG. 18 is a diagram for explaining the operation of a bubble jet head as an example of an ink jet head to which the present invention is applied. , FIG. 19 is a perspective view showing an example of a bubble jet recording head, FIG. 20 is an exploded perspective view, FIG. 21 is a view of the lid substrate viewed from the back, and FIG. 22 is a detailed view of the bubble jet recording head. Figure 2 to explain
3 is a diagram for explaining the structure of a bubble generating means using a heating resistor, and FIGS. 24 to 31 are diagrams showing the configuration of a conventional heating element layer, respectively. The figure shows an example in which the thickness of the protective layer, heat storage layer, or heat generating layer is gradually changed, and Figures 27 to 31 are examples in which the pattern width of the heat generating layer is gradually changed. . DESCRIPTION OF SYMBOLS 10... Substrate, 11... Heat storage layer, 12... Heat generating layer, 13... Control electrode, 14... Earth electrode, 15
... Protective layer, 16 ... Heat sink, 17 ... Insulating layer,
18...Generated bubbles/

Claims (1)

[Claims] 1. An ejection port for ejecting a liquid to form flying droplets, a heating resistor layer for causing a state change in the liquid due to heat and ejecting the liquid, and an electrical connection to the heating resistor layer. In a liquid jet recording device equipped with a liquid jet recording head having a pair of electrodes that are electrically connected to each other, a heat dissipation structure is formed so as to have a thermal gradient in the current direction in the vicinity of the heating resistor layer, and The heat dissipation structure is made of a material having a thermal conductivity higher than that of a material constituting a layer that is present above or below the heat dissipation structure in contact with the heat dissipation structure in the vicinity of the heating resistor layer. 1. A liquid jet recording device characterized in that the input energy is made variable according to image information.