JPH03224742A - Liquid jet recording device and method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid jet recording apparatus and method, more specifically,
The present invention relates to a liquid jet recording device and a recording method that enable gradation recording using 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,
However, the so-called inkjet recording method, which allows recording on plain paper without the need for special fixing treatment, is an extremely powerful recording method, and various methods have been proposed, improved, and commercialized. Some have been developed, and efforts are still being made 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. There are several types of methods depending on the control method used to control the flight direction of the generated recording liquid droplets.

First, the first method is the one disclosed in, for example, USP 3060429 (Tele type method), in which small droplets of recording liquid are generated by electrostatic attraction, and the generated droplets of recording liquid are used as a recording signal. The electric field is controlled accordingly.

Recording is performed by selectively depositing recording liquid droplets onto a 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. (Swe
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, a charge is electrostatically induced in the recording liquid droplet ejected by the charging electrode, and the droplet is charged with an amount of charge according to the recording signal.6 The recording liquid droplet with a controlled amount of charge is kept constant. When it flies between deflection electrodes where an electric field is uniformly applied, it is deflected according to the amount of charge added,
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 USP 3747120 (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 Stemme 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 Stemme method applies an electrical recording signal to a piezo vibrating element attached to a recording head that has an ejection port for discharging 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 recording liquid droplets, but on the other hand, it is difficult to control the atomization state and fog occurs in the recorded image. In addition, it is difficult to create a multi-nozzle recording head.
There are various problems such as being unsuitable for high-speed recording.

The fourth method has relatively many advantages compared to the first to third methods. In other words, the structure is simple, and since recording is performed by ejecting recording liquid from the ejection opening of the nozzle on-demand, it is possible to reduce the number of small droplets that fly as in the first to third methods. 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 It has great advantages such as a high degree of freedom. On the other hand, it is difficult to make the recording head multi-nozzle because there are problems in processing the recording head, and it is extremely difficult to miniaturize the piezoelectric vibrating element having the desired resonance number. This method has drawbacks such as that it is not suitable for high-speed recording because the recording liquid droplets are ejected and ejected in flight using the mechanical energy of the mechanical vibration of the piezoelectric vibrating element.

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 converter equipped with a heat generating part having a heat generating plate adjustment structure, and recording gradation by causing the heat generating part to generate an amount of heat according to the signal. It was intended to be. in particular.

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 27 to 29 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, and 73 is a heating element.

74 and 75 are electrodes, and 76 is a protective film. In the example shown in FIG. 24, by providing the protective film 76 with a thickness gradient from the electrode 74 side toward the electrode 75, A gradient is provided in the amount of heat that acts on the liquid that is in contact with the surface per unit time.

Further, in the example shown in FIG. 28, the thickness of the accumulation layer 72 is gradually decreased from A to B in the heat generating part ΔQ,
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 heat generating portion ΔQ.

Further, in the example shown in FIG. 29, the thickness of the heating element 73 is formed on the registration layer 62 by providing a gradient in the thickness of the heating element 73 at the heating part ΔQ. The amount of heat generated per unit time is controlled by changes in resistance at a location.

In addition, Figures 30 to 34 are respectively
FIG. 9 to FIG. 13 of Publication No. 9-31943 are planar structural views showing examples of the electrothermal converter disclosed in FIG. 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. 31 and 32, the central portion of the heat generating portion 81 has a planar shape that is thinner than both ends. Moreover, the example shown in FIG.
The planar shape of the heat generating part 81 is a trapezoid, and electrodes 82 and 83 are connected to opposite, non-parallel sides of the trapezoid as shown in the figure.

Further, in the example shown in FIG. 34, the central part of the first 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 the 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. 27 to 29 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 30 to 3
When the pattern width was changed as shown in Fig. 4, 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, in the prior art, various attempts have been made to perform gradation recording, but satisfactory results have not always been obtained in terms of manufacturing, durability, or high-density arrangement. do not have.

Purpose The present invention was made in view of the above-mentioned circumstances.
The first objective is to provide a liquid jet recording device that is easy to manufacture, has excellent durability, and is capable of gradation recording that allows for high-density arrays.The other objective is to propose a gradation recording method. It's about doing.

To achieve the above object, the present invention provides (1) an ejection port for ejecting a liquid to form flying droplets, and a state change due to heat in the liquid for ejecting the liquid. In a liquid jet recording apparatus comprising a liquid jet recording head having an electrothermal converter layer for generating an electrothermal converter and a pair of electrodes electrically connected to the electrothermal converter layer, the electrothermal converter A heat dissipation structure is formed on the layer so as to have a thermal gradient in the current direction, and input energy is made variable according to image information, or (2) liquid is ejected to form flying droplets. an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and a pair of electrodes electrically connected to the electrothermal converter layer. In a liquid jet recording method using a liquid jet recording head having a liquid jet recording head, input energy is changed according to image information, a thermal gradient is generated in the current direction on the electrothermal converter layer, and a thermal gradient is generated on the electrothermal converter layer. or (3) an ejection port for ejecting liquid to form flying droplets and for ejecting the liquid. A liquid jet recording comprising a liquid jet recording head having an electrothermal converter layer for causing a state change in the liquid due to heat, and a pair of electrodes electrically connected to the electrothermal converter layer. In the apparatus, a heat dissipation structure is formed under the electrothermal converter layer so as to have a thermal gradient in the direction of current flow, and the input energy is made variable according to image information, or (4) the liquid is ejected. an ejection port for forming flying droplets; an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the predistributed liquid; In a liquid jet recording method using a liquid jet recording head having a pair of electrodes connected to the electrode, the input energy is changed according to image information to generate a thermal gradient in the current direction under the electrothermal converter layer. (5) to eject the liquid to form flying droplets; and (5) to eject the liquid to form flying droplets. an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and a pair of electrodes electrically connected to the electrothermal converter layer. In a liquid jet recording apparatus having a liquid jet recording head, a heat dissipation structure is formed on the electrothermal converter layer so as to have a thermal gradient in the current direction, and the heat dissipation structure is one of the pair of electrodes. The input energy can be made variable depending on the image information, or
(6) an ejection port for ejecting a liquid to form flying droplets; an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid; In a liquid jet recording device comprising a liquid jet recording head having a pair of electrodes electrically connected to a converter layer, a heat dissipation structure is provided so as to have a thermal gradient in the current conduction direction under the electrothermal converter layer. (7) The heat dissipation structure also serves as one of the pair of electrodes, and the input energy is made variable according to the image information, or (7) the liquid is ejected to form flying droplets. an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and a pair of electrothermal converters electrically connected to the electrothermal converter layer. In a liquid jet recording apparatus equipped with a liquid jet recording head having an electrode, a heat radiation structure is formed on the electrothermal converter layer so as to have a thermal gradient in the direction of current flow, and the heat radiation structure is located on the ejection port side. (8) A discharge port for discharging liquid to form flying droplets; A liquid jet recording head includes an electrothermal converter layer for causing a state change due to heat in the liquid for ejection, and a pair of electrodes electrically connected to the electrothermal converter layer. In the liquid jet recording device, a heat dissipation structure is formed below the electrothermal converter layer so as to have a thermal gradient in the direction of current flow, and the heat dissipation structure is provided to have a greater heat dissipation effect on the ejection port side. , the input energy is made variable according to the image information, or (9
) an ejection port for ejecting a liquid to form flying droplets; an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid; and the electrothermal converter. comprising a liquid jet recording head having a pair of electrodes electrically connected to the layer, and forming a heat dissipation structure on the electrothermal converter layer so as to have a thermal gradient in the direction of current flow;
In a liquid jet recording device in which the heat dissipation structure also serves as one of the pair of electrodes and input energy is varied according to image information, the heat dissipation structure has a greater heat dissipation effect on the ejection port side. or (10) an ejection port for ejecting the liquid to form flying droplets, and electricity for causing a state change in the liquid due to heat in order to eject the liquid. a heat converter layer;
A liquid jet recording head is provided with a pair of electrodes electrically connected to the electrothermal converter layer, and a heat dissipation structure is provided below the electrothermal converter layer so as to have a thermal gradient in the direction of current flow. In the liquid jet recording device, the heat dissipation structure also serves as one of the pair of electrodes, and the input energy is made variable according to image information. It is characterized by being formed to have a greater heat dissipation effect on the sides. Hereinafter, the present invention will be explained based on examples.

FIG. 21 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. 22 is a perspective view showing an example of a bubble jet head, and FIG. A lid substrate (FIG. 23(a)) and a heating element substrate (FIG. 23(a)) constituting the head shown in FIG.
Figure 24 is a perspective view when disassembled in Figure (b)).
This is a perspective view of the lid substrate shown in FIG. 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, 31
is a bubble, and 32 is a flying ink droplet, and the present invention is applied to such a bubble jet type liquid jet recording head.

First, ink ejection by a bubble jet will be described with reference to FIG. 21. (a) is a steady state, in which the surface tension of the ink 30 and external pressure are in equilibrium on the orifice surface.

In (b), the heater 29 is heated, and the surface temperature of the heater 29 rises rapidly, and the adjacent ink layer is heated until an image is formed, 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 0+a/see.

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. 25 is a diagram showing a typical example for explaining the main part configuration of the liquid jet recording head as described above, and FIG. 25(a)
25(b) is a detailed front partial view of the bubble jet recording head as seen from the orifice side, and FIG. 25(b) is a partial cross-sectional view of 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. 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
Lower layer 50 provided on base 43. It is composed of 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 layer 51 in order to generate heat, and the heating resistance layer between these electrodes allows the heat generating portion 4 to be
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 part 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 part. 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. 26 is a detailed diagram for explaining the structure of a bubble generating means using one heating resistor, and in FIG.
Reference numeral 2 indicates an electrode, 63 indicates a protective layer, and 64 indicates a power supply device. Materials useful 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, tankle, 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 according to its area, material, shape and size of the heat-acting part, and actual power consumption, etc. so that the amount of heat generated per unit time is as desired. However, in the normal case, o, oot
~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, A Q y A g HA ur P t
Examples include rCu, which is 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 a method for applying heat to the liquid in order to eject the liquid. In a liquid jet recording apparatus comprising a liquid jet recording head having an electrothermal converter layer and a pair of electrodes electrically connected to the electrothermal converter layer for causing a state change due to the electrothermal So that there is a thermal gradient in the current direction on or below the converter layer,
A heat dissipation structure is formed and input energy is made variable according to image information, or an ejection port is used to eject liquid to form flying droplets.

A liquid jet recording head comprising an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and a pair of electrodes electrically connected to the electrothermal converter layer. In the liquid jet recording method used, the input energy is changed according to the image information, a thermal gradient is generated in the current direction on or below the electrothermal converter layer, and the bubbles generated on the electrothermal converter layer are suppressed. It is characterized in that the amount of liquid discharged from the discharge port is changed by changing the size of the discharge port.

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 (
a) A sectional view taken along the line B-B in the figure, in which 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 not provided uniformly over the entire surface of the heating element layer 12, but rather in the first
As shown in the figure, the area covering the heat generating layer 12 changes from the control electrode 13 side to the ground electrode 14 side. By doing so, it is possible to create a thermal gradient in the direction of current flow on one heating element layer due to the effect of the heat radiator. The material for forming the heat dissipation body is generally A, which has high thermal conductivity and can be easily formed into thin films such as evaporation and sputtering, and microfabricated by photoetching.
Q, Au, etc. are preferably used. 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. In the case of FIG. 1, the heat radiator 16 is formed in direct contact with the heat radiator layer, but the pattern of the heat radiator 16 is designed so that the heat radiator 16 does not function as a ground electrode. Appropriate insulation treatment 17 is performed without contacting the electrode 14. For a head having such a thermal gradient on the heat generating layer, the present invention further changes the input energy to the heat generating layer in accordance with 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 FIG. 3, the bubbles 18 gradually increase in size from the small bubble 1 to 2, 3.4.

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 50Ps.
As long as it is changed within the range of ec, there is no problem in practical terms.

FIG. 6 is a diagram for explaining another embodiment of the present invention, in which a heat sink 16 is formed under the heat generating layer 12. FIG. 7 shows yet another embodiment, in which a heat sink 16 is formed on the protective layer 15. FIGS. 8 and 9 show modified examples of the pattern of the heat dissipation body. 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 due to an appropriate 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 (for example, Afl) is used, a protective film should be provided. Also, Figures 1 and 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 2 μm thick SiO2 film is grown on the surface of a silicon wafer by thermal oxidation to form the heat storage layer 12. Next, as the heating element layer 13, HfB2
2,200 people sputter. Next, 8000 AQ layers were deposited as the heat sink 16. Next, electrode 13.1
As 4, Au is 1ooo.

People were deposited. At this time, SiO is formed as the insulating layer 17 so that the heat sink A+2 and the electrode Au do not come into contact with each other.

Next, as the protective film 15 of the heating element layer, SiO2 was deposited at a concentration of 9000
People sputtered. Further, 3000 Ta was sputtered thereon as an anti-cavitation layer.

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 μm×80/Am. Note that the electrode [11 is 24μ in the short direction of the heating element pattern.
It is m.

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 5 in 2 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 where the heat sink is not covered 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 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
The present invention is applied to a heating element substrate having an electrode laminated structure in order to enable a high-density arrangement of more than a book/picture, and a heat radiating element is formed. 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). , )), on this electrode 13 there is at least a portion A from which the lead wire is taken out;
An insulating layer 17 is provided except for a portion B to which a heating resistor layer 12 (described later) is connected (FIG. 13(b)). Next, a heating resistor N12 is provided (FIG. 13(c)), and
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). be. In the figure,
91 is a heating element (Hf B,), 92 is a first electrode (AQ)
, 93 is an insulating layer (Sin-), 94 is a second electrode (AQ)
, 95 is a thermal insulation layer (Sin2), 96 is an anti-cavitation layer (Ta), 97 is an electrode protection layer (Photonice),
98 is a bonding pad. The shaded area is the pattern formed in each step. (a) 5 on the surface due to thermal oxidation, etc.
A heating element 91 is formed on the S1 wafer on which the in2 film is formed. Here, HfB2 was formed by 3000 person sputtering as a heating element material. (b) AQ92 was formed as a first electrode by sputtering with 10,000 people. (c) 800% SiO2 as the insulating layer 93
It was formed by zero-person sputtering.

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) AQ94 was formed as a second electrode by 10,000 person 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 Note that Afl is excellent as an electrode material and has good thermal conductivity, so it is one of the most suitable materials for heat dissipation structures. (e) Next, Sio2 was formed as a thermal insulating layer 95 by sputtering with 5,000 people. This is the anti-cavitation layer described later,
This is to thermally separate the heat dissipation structure from the above-mentioned heat dissipation structure so that the heat dissipation structure can better perform its function. (f) Ta was formed as the anti-cavitation layer 96 by sputtering with 3,000 people. This is to absorb the physical impact force when the generated bubbles disappear, protect the heating element from damage, and extend its life. (g) As the electrode protective layer 97, 1 layer of Photonice (manufactured by Toshiku Co., Ltd.) was used.
2000 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. In the figure, 101 is the first electrode (Afl), 102 is the insulating layer (Sin), 103 is the heating element (HfB2), 10
4 is the second electrode (AQ), 105 is the heating element protective layer (Sin
2) , 106 is an anti-cavitation layer (Ta), 10
7 is an electrode protective layer (Photonice), and 108 is a bonding pad. The shaded area is the pattern formed in each step.

(,) S with a Sio2 film formed on the surface by thermal oxidation etc.
AQ was formed as a first electrode 101 on an i-wafer by sputtering with 10,000 people. This first electrode is
It also serves as a heat dissipation structure, and as is clear from the figure, the pattern of the part where heat generating elements are laminated via an insulating layer (described later) has a thermal gradient due to heat dissipation in the direction of current flow of the heat generating elements. The area it occupies is changing continuously. (b) As the insulating layer 102, SiO□ was formed by sputtering with 8,000 people. 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, HfB was formed by sputtering with 3000 people.

(d) AQ was formed as the second electrode 104 by sputtering with 10,000 people. (e)? A layer of Sio was formed as a heat generating element protective layer 105 on K by 10,000 sputtering. 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 with 3,000 people. This is to absorb the physical impact force when the generated bubbles disappear, protect the heating element from damage, and extend its life. (g) 1 layer of Photonice (manufactured by Toshiku Co., Ltd.) was used as the electrode protective layer 107.
2000 people were formed. Although the explanation is omitted, each of the embodiments explained in FIGS. 14 to 17 above,
The pattern is formed using a positive photoresist 0FPR (Tokyo Ohka Co., Ltd.) after each layer is formed by sputtering.
Each pattern was formed by photolithography and etching.

18(a) to (n) are for explaining one embodiment of the liquid jet recording device of the present invention (corresponding to claims 5 and 7, particularly the detailed structure of claim 7), and show the manufacturing process. are shown in order. This will be briefly explained below. In addition, the branch number 1 in the figure is a plan view, and 2 is an AA sectional view of 1, respectively.

(a) A 5in2 film of 1 to 2μ is deposited on a Si wafer by thermal oxidation.
m grow.

(b) Sputtering HfB2 as a heating element material.

(c) Sputtering Afi as the first electrode material.

(d) A pattern is formed by photolithography and etching to form a lead electrode pattern.

Note that for the sake of simplicity, only two elements are shown in the plan view (d)-1.

(e) AQ of the heating element portion is removed by photolithography and etching to expose the 5 heating layer.

(f) Sputter 5in2 over the entire surface to form an insulating layer.

(g) Remove SiO2 from the contact hole portion by photolithography and etching.

(h) Sputtering AQ as the second electrode material.

(i) Afl on the heating element, part of the lead electrode, and the bonding pad area is removed by photolithography and etching. Since the AQ as the second electrode also serves as a heat dissipation structure in the present invention, the AQ on the heating element is not completely removed, but the shape is such that the area covered by the AQ gradually changes. to be removed. Note that (n
), a cutting process is involved when forming the discharge port, but the area where AQ exists is on the right side (on the heating element side) of the cutting part so that AQ is not exposed at that time.

(j) Sputtering Sin as a thermal insulating layer and protective layer over the entire surface, and removing SiO□ at the bonding pad portion by photolithography and etching.

(k) As an anti-cavitation layer, Ta is sputtered and formed by photolithography and etching so as to cover the vicinity of the heating element.

(1) Form a polyimide layer as a protective layer for the lead electrode portion.

(m) Laminate dry film photoresist and form a channel pattern by photolithography. In the present invention, a pattern is formed so that the left side of the figure is the discharge port, and the positional relationship between the heat dissipation structure and the discharge port is as follows. In other words, the heat dissipation structure is provided so as to have a greater heat dissipation effect on the discharge port side.

(n) Join the lid plate onto the dry film channel and cut the discharge port to complete the discharge port.

FIG. 19 shows a rectangular heating element extending in the direction of the ejection port and a rectangular heating element formed above (or below) the ejection port in order to make it easier to understand the principle that the ink ejection amount changes due to ejection of the recording device of the present invention. This figure shows an AΩ heat dissipation structure, an ink flow path, and an ejection port.

FIGS. 20(a) to 20(c) show how the ink ejection amount changes due to the ejection of the recording apparatus of the present invention, and FIG. 20(a)
1 shows the case where the input energy is small, FIG. 9B shows the case where the input energy is medium, and FIG. In the present invention, the heat dissipation structure is formed to have a greater heat dissipation effect on the discharge port side. Therefore, when the input energy to one heating element is small as shown in Figure 20(a), much of the heat generated by the heating element is instantly absorbed by the heat dissipation structure and diffused, causing film boiling. As shown in the figure, the area where bubbles are generated is far from the discharge port, and the bubbles generated in that area are narrow and small. Therefore, the volume of the ink droplets ejected from the ejection ports is small and is used to form minute dots. Next, as shown in FIGS. 2(b) and 2(c), the input energy is gradually increased, that is, specifically, the driving voltage of one heating element is increased. Alternatively, if the pulse width is not too long (less than 50 μsec), then if the pulse width is made longer, the heat generation effect of the heating element influences the system more than the heat dissipation effect of the heat dissipation structure, so the film boiling region will change depending on the input energy. increases in the direction of the ejection port, that is, the area where the temperature at which film boiling occurs increases in the direction of the ejection port, so that a boiling film grows so as to push ink toward the ejection port.

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. 23(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. On the other hand, 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.

Effect As is clear from the above explanation, claim 1 (structure 1
), according to the invention described in Item 3 (Structure 3), a heat dissipation body is formed in a two-dimensional manner by using a thin film forming technique, a photolithography technique, a photoetching technique, etc. on the heat generating body part of a conventionally known bubble jet head. Since it can be formed, manufacturing is easy and can be done with high precision. Further, according to the invention described in the second aspect (configuration 2) and the fourth aspect (configuration 4), by changing the input energy using the head formed as described above, it is possible to easily eject ink. Since the amount can be controlled, there are advantages such as gradation recording becomes possible.

Furthermore, a common effect of Structures 5 and 6 is that the layer structure of the heating element section is simplified by providing one of the electrodes with the function of a heat dissipation structure. This improves the efficiency of heat transfer to the ink, extremely reduces deterioration or disconnection of the heating element due to thermal stress, lengthens the life of the heating element, or improves yield in the manufacturing process. There is also a significant advantage in terms of reduced manufacturing costs due to simplification. Furthermore, similar to the effects of claims 2 (structure 2) and 4 (structure 4), the amount of ejected ink can be easily controlled by using the liquid jet recording apparatus of the present invention and changing the input energy. , gradation recording becomes possible. In particular, as an effect corresponding to configuration 5, since the second electrode, that is, the heat dissipation structure is formed closer to the ink, the effect of the heat dissipation structure is large and is particularly advantageous for controlling the ejection amount. A corresponding effect is that since the heating element is formed closer to the ink, the efficiency of heat transfer to the ink is improved.

In addition, claim 5 (configuration 7) to claim 8 (configuration 1)
As shown in 0), by clarifying the positional relationship between the heat dissipation structure and the ejection port, not only can the bubble volume be varied, but the growth direction of the bubbles also grows toward the ejection port, improving ink ejection power and efficiency. It is also effective in terms of energy saving.

[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 each show other embodiments of the present invention, and FIGS. 8 and 9 each show modified examples of the heat sink pattern. FIG. 10 is a diagram for explaining another embodiment of the present invention,
FIGS. 11 to 13 are diagrams for explaining other embodiments of the present invention, FIGS. 14 and 15 are diagrams showing the manufacturing process of the heating element substrate of the present invention, and FIGS. 17th
The figure shows another embodiment of the manufacturing process of the heat generating substrate according to the present invention, and FIGS. FIG. 19 is a diagram showing the relationship between the manufacturing process in order, and FIG.
~(c) are diagrams showing how the ink ejection amount changes, FIG. 21 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, and FIG. , FIG. 23 is a perspective view showing an example of a bubble jet recording head, FIG. 23 is an exploded perspective view, FIG. 24 is a view of the lid substrate viewed from the back, and FIG. 25 is a diagram for explaining details of the bubble jet recording head. 26 are diagrams for explaining the structure of a bubble generating means using a heating resistor,
FIGS. 27 to 34 are diagrams showing the configurations of conventional heat generating layers, respectively, and FIGS. 27 to 29 show structures in which the thickness of the protective layer, heat storage layer, or heat generating layer is gradually changed. The examples shown in FIGS. 30 to 34 are examples in which the pattern width of one heating element 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. Figure 1 (a) Figure (b) Voltage (v) Size of air envelope (#n1 (b). Figure 8 Figure 0 Figure (a) 65 No. 1 Fig. 1, j Fig. 3 Fig. 18 (d-I Fig. 8 + f) J Fig. 8 <7+-1 (k-n Fig. 8 tl+-1 Fig. 19 Fig. 0 Fig. 1 Bow =: Fig. 2 Fig. 23 Fig. 4 Fig. 5 Fig. IQ) (Fig. 6 Fig. 7 Fig. 28 Fig. 9 Fig. 0 Fig. 1 Fig. 2 Fig. 4)

Claims (1)

[Claims] 1. An ejection port for ejecting a liquid to form flying droplets, and an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid. and a pair of electrodes electrically connected to the electrothermal converter layer. 1. A liquid jet recording device characterized in that a heat dissipation structure is formed as described above, and input energy is made variable according to image information. 2. An ejection port for ejecting a liquid to form flying droplets, an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and the electrothermal converter. In a liquid jet recording method using a liquid jet recording head having a pair of electrodes electrically connected to a body layer, the input energy is changed according to image information, and the input energy is changed in the current direction on the electrothermal converter layer. A liquid jet recording method characterized in that the amount of liquid ejected from the ejection port is changed by creating a thermal gradient and changing the size of bubbles generated on the electrothermal converter layer. 3. An ejection port for ejecting a liquid to form flying droplets, an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and the electrothermal converter. In a liquid jet recording device including a liquid jet recording head having a pair of electrodes electrically connected to a body layer, a heat dissipation structure is provided below the electrothermal converter layer so as to have a thermal gradient in the direction of current flow. A liquid jet recording device characterized by forming a body and making input energy variable according to image information. 4. An ejection port for ejecting a liquid to form flying droplets, an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and the electrothermal converter. In a liquid jet recording method using a liquid jet recording head having a pair of electrodes electrically connected to a body layer, the input energy is changed according to image information, and the current direction is changed under the electrothermal converter layer. creating a thermal gradient in
A liquid jet recording method characterized in that the amount of liquid discharged from the discharge port is varied by changing the size of bubbles generated on the electrothermal converter layer. 5. An ejection port for ejecting a liquid to form flying droplets, an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and the electrothermal converter. In a liquid jet recording device including a liquid jet recording head having a pair of electrodes electrically connected to a body layer, a heat dissipation structure is provided on the electrothermal converter layer so as to have a thermal gradient in the direction of current flow. A liquid jet recording apparatus characterized in that the heat dissipation structure is provided so as to have a greater heat dissipation effect on the ejection port side, and input energy is made variable in accordance with image information. 6. An ejection port for ejecting a liquid to form flying droplets, an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and the electrothermal converter. In a liquid jet recording device comprising a liquid jet recording head having a pair of electrodes electrically connected to a body layer, a heat dissipation structure is provided below the electrothermal converter layer so as to have a thermal gradient in the direction of current flow. 1. A liquid jet recording apparatus characterized in that the heat radiation structure is provided so as to have a greater heat radiation effect on the ejection port side, and input energy is made variable in accordance with image information. 7. An ejection port for ejecting a liquid to form flying droplets, an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and the electrothermal converter. a liquid jet recording head having a pair of electrodes electrically connected to a body layer; a heat dissipation structure is formed on the electrothermal converter layer so as to have a thermal gradient in the current direction; The structure also serves as one of the pair of electrodes,
1. A liquid jet recording device in which input energy is variable according to image information, wherein the heat radiation structure is formed to have a greater heat radiation effect on the ejection port side. 8. An ejection port for ejecting a liquid to form flying droplets, an electrothermal converter layer for causing a state change in the liquid due to heat in order to eject the liquid, and the electrothermal converter. a liquid jet recording head having a pair of electrodes electrically connected to a body layer; a heat dissipation structure is formed below the electrothermal converter layer so as to have a thermal gradient in the direction of current flow; In the liquid jet recording device, the heat dissipation structure also serves as one of the pair of electrodes, and the input energy is made variable in accordance with image information, wherein the heat dissipation structure has greater heat dissipation on the ejection port side. What is claimed is: 1. A liquid jet recording device characterized in that the liquid jet recording device is configured to perform an action.