KR100221458B1 - Recording liquid ejecting apparatus of print head - Google Patents

Abstract

The present invention relates to a recording liquid ejecting apparatus for a printhead.

The present invention allows the restoring force to be increased by a pressure lower than atmospheric pressure when the film is restored to its original state while the film is cooled, so that the printing time is increased after the injection of the recording liquid, that is, the operating frequency is increased, thereby improving printing performance. A recording liquid injector of a head, in particular, a thin film of a shape memory alloy that changes shape according to a temperature change, a power supply unit that generates a temperature change of the thin film, and the thin film is combined to force a shape change than atmospheric pressure. A substrate having a low space portion, a liquid chamber provided on the thin film and storing a recording liquid therein, and a flow path plate having a flow path formed therein so that the recording liquid flows into one side of a wall surface surrounding the liquid chamber, and the flow path plate. The recording liquid may be sprayed in the form of droplets when the thin film is installed on the top and is changed in shape. The nozzle plate is characterized in that the nozzle plate is formed with a nozzle having a smaller area than the liquid chamber area of the flow path plate.

Description

Printhead spray from the printhead

1 is a cross-sectional view of a conventional heated injector.

2 is a cross-sectional view of a conventional piezoelectric element injector.

Figure 3 is an exploded perspective view of the injector of one embodiment of the present invention.

4 is a perspective view showing the recording liquid flow in one embodiment of the present invention.

Figure 5 is a front sectional view of the injector of one embodiment of the present invention.

6 is a side cross-sectional view of the injector of the embodiment of the present invention, in which a to d show before and after operation.

7 is a diagram showing a phase change of a thin film composed of the shape memory alloy of the present invention.

8 is a manufacturing process of the one-way thin film according to the present invention.

9 is a manufacturing process of the one-way thin film according to the present invention.

10 is a diagram showing the heating time and temperature of the thin film of the present invention.

Figure 11 is a schematic diagram showing a sample for the residual compressive stress test of the thin film of the present invention.

* Explanation of symbols for main parts of the drawings

10 substrate 11 space part

12: thin film 12a: pressure plate

13: Europan 14: liquid chamber

16: Euro 18: nozzle plate

19: nozzle 20: recording liquid

21: power supply

The present invention relates to a recording liquid injector of a printhead, and more particularly, to allow the pressure of the liquid chamber to be adjusted by deformation in the process of changing the thin film abnormality, and to allow the thin film to be pulled and restored by a pressure lower than atmospheric pressure, thereby operating frequency. The present invention relates to a recording liquid ejecting apparatus for a print head, in which print performance is increased, the manufacturing process can be made compact, and the manufacturing process is simplified.

In general, a widely used printhead uses a DoD On Demand (DOD) method. The DOD method is increasingly used because it does not need to charge or deflect recording liquid drops, does not require high pressure, and can easily print by spraying the recording liquid droplets under atmospheric pressure. Typical spraying principles include a heating spray method using a resistance and a vibration spray method using a piezo-electric.

Fig. 1 is for explaining the principle of the heating jetting method, which has a chamber a1 in which recording liquid is incorporated, and has an injection hole a2 for improving the recording material from this chamber a1. At the bottom of the chamber a1, on the opposite side, a resistor a3 is embedded to cause the air to expand. Therefore, the bubble expanded by resistance causes the recording liquid in the chamber a1 to be pushed out to the injection port a2, and the recording liquid is ejected toward the recording material by the force.

However, this heating spray method causes a chemical change since the recording liquid is heated to heat, and the recording liquid adheres to the inner diameter of the injection hole (a2), causing clogging. Documents must be used, resulting in poor document retention.

Fig. 2 is for explaining the principle of the vibrating jetting method by the piezoelectric element, and there is also a chamber b1 in which recording liquid is incorporated, and there is an injection hole b2 from the chamber b1 toward the recording material. Piezoelectric elements (Piezo Transducer) is embedded in the bottom opposite the injection port is configured to cause vibration.

As described above, when the piezoelectric element b3 causes vibration at the bottom of the chamber b1, the recording liquid is pushed out to the injection hole b2 by the vibration force, and thus the recording liquid is transferred to the recording material by the vibration force. To be sprayed.

As the spraying method by vibrating the piezoelectric element does not use heat, there is a wide range of choice of the recording liquid, but it is difficult to process the piezoelectric element, and in particular, the operation of attaching the piezoelectric element to the bottom of the chamber b1 is difficult. Since it is difficult, there exists a problem that mass productivity falls.

In order to solve the various problems described above, the present inventors are in the application of a printhead to allow the recording liquid to be injected while the pressure of the liquid chamber is changed by the deformation generated during the phase change process of the thin film. According to the pre- filed printhead, the actuating force of the thin film is increased to reduce the clogging of the nozzle and the deformation of the thin film is large. Therefore, the thin film can be manufactured in a small size. Since the thin film can be attached to the substrate by using the, the aspect is increased.

The present invention relates to an improvement of a pre- filed printhead, and an object of the present invention is to increase its restoring force by a pressure lower than atmospheric pressure when the film is restored to its original state during cooling, so that the recording liquid is injected into the liquid chamber. It is an object of the present invention to provide a recording liquid ejection apparatus for a printhead in which the replenishment time, that is, the operating frequency is increased, thereby improving print performance.

In order to achieve the above object, the recording liquid jetting apparatus of the printhead according to the present invention includes a thin film of a shape memory alloy which changes shape according to temperature change, a power supply unit for generating a temperature change of the thin film, and the thin film is combined. A substrate having a space portion at a lower state than atmospheric pressure to be forcedly changed in shape, and a liquid chamber formed on the thin film and storing a recording liquid therein, and a flow channel having a flow path formed so that the recording liquid flows into one side of a wall surface surrounding the liquid chamber. And a nozzle plate provided on the flow path plate and having a nozzle having a smaller area than the liquid chamber area of the flow path plate so that the recording liquid can be ejected in the form of droplets when the thin film is changed in shape. There is a characteristic.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 is an exploded perspective view of the jetting apparatus of one embodiment of the present invention, and Figure 4 is a perspective view showing the recording liquid flow of one embodiment of the present invention. In the jetting apparatus of the present invention, in order to increase the resolution, the nozzles 19 to which the recording liquid 20 is sprayed are arranged in multiple rows vertically and horizontally, and the thin film 12 which substantially sprays the recording liquid 20 has each nozzle ( 19) and one-to-one correspondence.

That is, a plurality of spaces 11 penetrated in the vertical direction in front and rear of the substrate 10 are formed, and a plurality of thin films 12 are coupled to the upper portion of the substrate 10 to cover each space 11. It is provided. The thin film 12 causes a phase change in accordance with temperature to cause warpage and to spray the recording liquid 20 by the generated force generated at this time. In addition, the pressure plate 12a for making the space 11 lower than atmospheric pressure is coupled to the bottom of the substrate 10. When the pressure plate 12a is coupled, the interior of the space 11 is lower than atmospheric pressure, thereby forcing bending of the thin film 12 according to the degree of vacuum. Therefore, the bending strain rate (restoration force) of the thin film 12 is increased to increase the operating frequency.

In addition, a flow path plate 13 covering the upper portion of the substrate 10 is provided, and the flow path plate 13 is formed with a liquid chamber 14 in which the recording liquid 20 is accommodated in each of the upper portions of the thin film 12. In addition, an oil passage 15 through which the recording liquid 20 flows is provided in the center of the passage plate 13, and the oil passage 15 and the liquid chamber 14 communicate with each other through the passage 16. In addition, a liquid inlet 17 communicating with one side oil passage 15 of the flow path plate 13 is provided at one side of the substrate 10 to supply the recording liquid 20 toward the oil passage 15.

In addition, the nozzle plate 18 coupled to the upper portion of the flow path plate 13 is provided, and the nozzle plate 18 is provided with a plurality of nozzles 19 corresponding to each liquid chamber 14 formed in the flow path plate 13. In addition, each nozzle 19 corresponds to the thin film 12 exposed toward the corresponding liquid chamber 14, and when the thin film 12 is deformed, the pressure of the liquid chamber 14 changes so that the recording liquid 20 is in the state of droplets. It is sprayed onto the paper via each nozzle 19.

The thin film 12 is continuously changed in phase with temperature change, and vibration occurs due to deformation in this process, and the recording liquid 20 is sprayed in the form of droplets through each nozzle 19. 6A to 6B are side cross-sectional views of the injector of one embodiment of the present invention, in which one thin film is extracted. In the initial state convexly deformed to the opposite side of the nozzle 19 of the thin film 12, when the thin film 12 is heated above the set temperature, the thin film 12 is unfolded by phase change, and at this time, the internal pressure of the liquid chamber 14 is increased and compressed, and at the same time recording liquid 20 is sprayed through the nozzle 19. On the other hand, the space 11 maintains a state in which the degree of vacuum inside is increased, and when the thin film 12 falls below the set temperature, the space 11 is restored to its original convex state and the internal pressure of the liquid chamber 14 is lowered so that the nozzle ( The recording liquid 20 flows into the liquid chamber 14 through the liquid inlet 17, the oil passage 15, and the flow path 16 by the capillary phenomenon and suction force of FIG. 19. Thereafter, the above process is repeated continuously, and the recording liquid is sprayed in the form of droplets.

In addition, when the thin film 12 is deformed into a convex original state, the inside of the space part 11 pulls the thin film 12 to maintain a state lower than the original atmospheric pressure. Thus, the thin film 12 has a resilience force to increase the operating frequency. do. That is, the vacuum degree of the space part 11 increases the resilience of the thin film 12, so that it can be quickly restored, and thus the refilling of the recording liquid can be made quickly, so that the injection of the recording liquid can be performed immediately. The operating speed of the printhead is increased.

The thin film 12 is also heated by the power supply 21. That is, when the power of the power supply unit 21 is applied to the transfer root 21a coupled to both ends of the thin film 12, the thin film 12 is heated by a resistance, the temperature is increased, and deformation occurs due to phase change. In addition, when power is not applied to the power supply 21, the thin film 12 is naturally cooled and restored to its original convex state by deformation. In addition, the thin film 12 may use a separate heater without using the power supply unit 21. That is, a heater may be attached to the bottom of the thin film 12 to directly heat it.

The thin film 12 is a shape memory alloy (phase memory alloy) is used to change the phase according to the temperature and the material is made of titanium (Ti) and nickel (Ni). In addition, the thin film 12 composed of the shape memory alloy has a direction according to the manufacturing method. 8 is a manufacturing process diagram of a one-way thin film according to the present invention, Figures 3 to 6 is a one-way thin film. After depositing the thin film 12 on the substrate 10 made of a material such as silicon and heat-treated at a constant temperature for a predetermined time, it is changed into a crystallized austenite structure and the shape of the flat plate is memorized. Subsequently, when the martensite finish temperature (Mf) is cooled to about 45 ° C. or lower, the austenite structure becomes a martensite structure having 24 different orientations that are crystallographically equivalent so that the residual compressive stress exists in the thin film 12. do.

In addition, when the silicon substrate is directly etched in the lower portion of the thin film 12, the space portion 11 is formed on the substrate 10, and the thin film 12 is exposed to the outside, and is flexed and deformed toward the lower (or upper) portion due to residual compressive stress. Becomes The flexurally deformed thin film 12 maintains the martensite structure, and then, when the thin film 12 is raised to a set temperature, that is, the austenite termination temperature (Af) of about 70 ° C. or more, it is inversely transformed into austenite structure. It is changed and spread out in the form of a flat plate as shown in Fig. 6C. Then, when the thin film 12 is cooled, it is transformed into martensitic structure and is flexurally deformed by the residual compressive stress to be restored to its original state.

Also coupled to the bottom of the substrate 10 is a pressure plate 12a that makes the space 11 a vacuum lower than atmospheric pressure. The pressure plate 12a is made of glass (Corning # 7740) having similar thermal expansion coefficients and general characteristics to silicon, which is a material of the substrate 10, and is bonded to the bottom surface of the substrate 10 by electrostatic bonding in a vacuum state. In addition, a metal such as stainless or nickel, as well as a polymer may be used to insert a bonding layer between the substrate 10 and the pressure plate 12a to be bonded in a vacuum.

As such, the pressure plate 12a for making the space 11 lower than atmospheric pressure is coupled to the bottom surface of the substrate 10 to increase the bending strain rate (restoration force) when the thin film 12 is restored to its original state by bending deformation. In addition, as the internal pressure of the liquid chamber 14 is compressed and expanded in accordance with the temperature change of the thin film 12, the recording liquid is ejected in the form of droplets through the nozzle 19.

9 is a manufacturing process diagram of a two-way thin film according to the present invention. When the thin film 12 is heat-treated in the chamber 22 for a predetermined temperature for a predetermined time, the thin film 12 is changed into crystallized austenite structure, and when the martensite finish temperature (Mf) is cooled below about 45 ° C., the austenite structure is It is transformed into martensite tissue with 24 different orientations that are crystallographically equivalent. In addition, deformation is performed by applying an external force to the martensite structure within a range where plastic slip does not occur. At this time, the martensite structure is formed in a specific direction to have a desired displacement. Then, when the temperature of the austenite termination temperature (Af) is increased to about 70 ° C. or more, the martensite structure is inversely transformed into austenite structure and unfolded.

Thereafter, the above process is repeated several times, and then when the film 12 is lowered to a temperature below the martensite end temperature (Mf), bending deformation occurs even without external force and the austenite end temperature (Af). Increasing the temperature above is in the form of a flat plate causes a reciprocating motion in both directions depending on the temperature. In addition, the bidirectional thin film can be applied to a frit head that needs to obtain a high generating force because the amount of deflection is determined according to the degree of external force applied in the manufacturing process.

In addition, when manufacturing the bidirectional thin film 12, the pressure plate 12a is coupled to the lower portion of the substrate 10 to make the interior of the space portion 11 lower than atmospheric pressure. In this case, when the thin film 12 is restored to an initial state, the restoring force is increased according to the degree of vacuum of the space 11, thereby improving the operating frequency.

The thin film 12 having bidirectionality may be applied to FIG. 6, which is an embodiment of the present invention. For example, the thin film 12 is deposited on one side of the substrate 10, and then the space portion 11 is formed by silicon etching so that the thin film 12 is warped and deformed due to residual compressive stress. . In addition, when the pressure plate 12a is coupled to the bottom of the substrate 10 to make the space 11 lower than atmospheric pressure, and then the thin film 12 is heated and deformed into a flat plate, the vacuum degree of the space 11 is increased. When the thin film 12 is cooled and deflected to the convex original state, the bending strain rate, that is, the restoring force is increased by the degree of vacuum in this process.

In addition, the thin film 12 of the present invention is unfolded in the austenite structure according to the temperature difference and is flexurally deformed in the martensite structure, so that the frequency difference (operation parking number) of the thin film 12 increases as the temperature difference is reduced. Therefore, copper (Cu) may be added to an alloy of titanium (Ti) and nickel (Ni) to reduce the phase change temperature difference. As such, the shape memory alloy using titanium (Ti), nickel (Ni), and copper (Cu) reduces the phase change temperature difference, thereby increasing the frequency, ie, operating frequency, of the thin film 12, thereby increasing printing.

The droplet implementation of the thin film of the present invention configured as described above is as follows.

If the energy density generated by the thin film is 10 × 10 6 J / m 3, and the size of the thin film is 200 × 200 × 1 μm 3, the diameter of the droplet generated is 60 μm, it is possible to determine whether the thin film can be sprayed as follows. .

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U = energy required to generate droplets of the desired recording liquid

US = surface energy of recording liquid

UK = kinetic energy of recordings

R = diameter of the droplet

v = speed of recording liquid

ρ = density of recording liquid (1000 kg / ㎥)

γ = surface tension of recording solution (0.073 N / m)

If the desired droplet velocity is 10m / sec, the required energy (U)

The maximum energy generated by the film

이다.Required energy when the droplet diameter is 100㎛

to be.

이므로 원하는 크기의 액적을 구현할 수 있다. 즉 박막은 발생력이 매우 크기 때문에 원하는 기록액의 액적을 쉽게 구현할 수 있다.therefore,

Therefore, droplets of a desired size can be realized. That is, since the thin film has a very high generating force, droplets of a desired recording liquid can be easily realized.

In addition, when the displacement amount according to the heating time and energy consumption and residual compressive stress of an embodiment of the present invention is as follows. Heat is applied to the thin film 12 to generate heat according to the resistance, and the phase change occurs by the heat, but the heating time until the thin film 12 at 25 ° C. is heated to 70 ° C., that is, austenite structure. The excess energy consumption is as follows.

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Material of thin film = TiNi

Thin Film Length (1) = 400㎛

Density of thin film (ρ _s ) = 6450kg / ㎥

Temperature change = 70-25 = 45 ℃

Specific heat (C _p ) = 230 J / kg ℃

Specific resistance of thin film (ρ) = 80μ

Applied current (1) = 1.0A

Resistance line width (W) = 300㎛ (width of thin film)

Resistance height (t) = 1.0 μm (thin film height)

Heating time (t _h )

= 7.4 μsec

Heater resistance (R) = ρ (1 / w · t) = 1.1Ω

Power Consumption (I ² R) = 1.1 Watt

The energy needed to generate droplets

Heating time × Power consumption = 8.1 μJ

Therefore, the energy required for ejecting the recording liquid 18 to generate droplets is about 8.1 mu J, which consumes less energy than 20 mu J of the conventional heating method.

9 is a diagram showing the heating time and temperature of the thin film of the present invention, and the physical properties for the experiment are as follows.

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However, the thickness of the thin film 12 is 1 micrometer and the ambient temperature is 25 degreeC.

If the ambient temperature is 25 ℃, the time to cool to 30 ℃ after changing to austenite structure heated to 70 ℃ is converted to a frequency of about 200μsec is about 5㎑. Therefore, the operating frequency of the print head is about 5 kHz. However, since the temperature at which the deformation is completed (martensite end temperature) is about 45 ° C, there is no need to wait until it cools to 30 ° C, and it can be heated again before continuing to spray the recording liquid 18. Can be. Large operating frequencies increase printing speed.

In addition, when the displacement amount according to the residual compressive stress of the thin film is analyzed with reference to FIG.

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Material of thin film = TiNi

Young's Modulus of Thin Films = 50 GPa

Poisson's ratio (ν) = 0.3

The length of the film = a

Film thickness = h

Film width = b

Critical stress of thin film ()

Central displacement of thin film (W _s )

Using (1) and (2), when the residual compressive stress (S) of the thin film is 36 MPa (Compressive stress), the displacement amount of the thin film and the droplet size of the recording liquid 18 are shown in the chart below. At this time, the size of the droplet was calculated assuming that half of the volume change caused by the deformation of the thin film went out toward the liquid chamber 14 and the other half was sprayed out of the nozzle 19.

In addition, the calculation of the displacement amount of the thin film due to the pressure lower than the atmospheric pressure and the energy loss relationship in the injection of the recording liquid are as follows.

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The relationship between pressure and displacement is shown below.

P: pressure differance

ν: Poisson's ratio

E _δ : Young's modulus of the thin film

L: center distance of square thin film

δ: displacement of thin film

h: thickness of thin film

σ _o : residual stress

c: constant (3.41)

Ignoring the residual stress of the thin film, the pressure applied to the thin film is about atmospheric pressure (100 KPa). Under this pressure, if the amount of deformation of the thin film is found using the above equation, about 4.3 μm is generated.

When the displacement of the thin film is 4.3 µm, the volume (ΔV) change is

ΔV: (1/4) (W _o a ² ) = 4.3 × 10 ^-14 ㎥)

The energy (W) consumed by the pressure difference (atmospheric pressure) when the film becomes flat

W = P.ΔV = 4.3 × 10 ^-9 J)

The maximum energy that the thin film (200 × 200 × 1μ㎥) can exert is (W _max )

W _max = W _υV

W _v : maximum energy per unit volume of thin film (10 × 10 ⁶ J / ㎥)

V: volume of thin film

W _max = 10 × 10 ⁶ ) · (200 × 200 × 1) = 4.3 × 10 ^-1 J

The energy ratio (W / Wmax) consumed by the pressure below atmospheric pressure is 1% compared to the maximum energy the thin film can produce. Therefore, the influence of the pressure difference in discharging the recording liquid can be ignored.

As described above, according to the present invention, the thin film for ejecting the recording liquid causes a phase change as the temperature is changed, and the recording liquid is ejected by the deformation in this process. In addition, the space portion formed in the substrate is maintained by the pressure plate lower than atmospheric pressure. Therefore, when the thin film is restored to its initial state, the restoring force is strengthened by the degree of vacuum, and the operating frequency is increased. Also, since the thin film has a large displacement, each space portion formed in the substrate and each liquid chamber formed in the flow path plate can be made small. The overall size is reduced and can be made compact, which is advantageous for achieving high resolution by increasing the concentration of nozzles.

In addition, since the generating force is large, the pushing force of the recording liquid is increased to reduce the clogging of the nozzle, thereby improving reliability, and the droplet size of the recording liquid can be sufficiently reduced, which is advantageous for achieving high image quality. In addition, the driving voltage is less than 5 volts, so it is easy to design and manufacture the driving circuit, and it is possible to deposit a thin film, which is a shape memory alloy, on the surface of the substrate made of silicon wafer using the existing semiconductor process. It has the effect of being.

Claims (19)

Atmospheric pressure such that the thin film 12 of the shape memory alloy, which changes in shape according to temperature change, the power supply 21 for generating a temperature change of the thin film 12, and the thin film 12 are forcibly changed in shape. A substrate 10 having a lower space portion 11 and a liquid chamber 14 provided on the thin film 12 and for storing the recording liquid 20 are formed, and a wall surface surrounding the liquid chamber 14 is formed. A flow path plate 13 having a flow path 16 formed thereon so that the recording liquid 20 flows into one side thereof, and the recording liquid 20 installed on the flow path plate 13 when the thin film 12 is changed in shape. The recording liquid jetting apparatus of the printhead comprising a nozzle plate 18 having a nozzle 19 having an area smaller than the area of the liquid chamber 14 of the flow path plate 13 so that the jet can be ejected in the form of droplets. The apparatus according to claim 1, wherein the thin film 12 is a shape memory alloy mainly composed of titanium (Ti) and nickel (Ni). The apparatus according to claim 1, wherein the thin film 12 is a shape memory alloy to which copper (Cu) is further added to reduce the phase change temperature difference to increase the operating frequency. The recording liquid jetting apparatus of claim 1, wherein the thin film 12 has a thickness of 0.5 μm to 3 μm. The method of claim 1, wherein the substrate 10 is coupled to the thin film 12 on the upper portion of the space portion 11 that is open to the upper and lower side to make the inside of the lower portion of the space portion 11 lower than atmospheric pressure The recording liquid injector of the printhead, characterized in that the pressure plate 12a is coupled The printing liquid jetting apparatus of claim 5, wherein the pressure plate 12a is made of metal and adhered to a vacuum by putting an adhesive between the substrate 10 and the substrate 10. The recording liquid jetting apparatus according to claim 5, wherein the pressure plate (12a) is made of a polymer and adhered in a vacuum by putting an adhesive between the substrate and the substrate (10). The recording liquid jetting apparatus of claim 5, wherein the substrate 10 is made of silicon. The recording liquid jetting apparatus of claim 8, wherein the input plate 12a is a glass material having a similar thermal expansion coefficient and various properties to the silicon. 10. The recording liquid jetting apparatus of claim 9, wherein the input plate 12a is electrostatically bonded to the substrate 10 in a vacuum state. When the thin film 12 is heated to an austenite termination temperature and changed into an austenite structure, the thin film 12 is unidirectional, which is flexurally deformed by residual compressive stress when cooled to below the end temperature of martensite and changed into martensite structure. Recording liquid injection device of the printhead, characterized in that The method of claim 11, wherein the thin film 12 is deposited on the surface of the substrate 10 to be phase changed into a martensite structure having residual compressive stress, and the space 11 is formed by silicon etching to form the thin film 12. ), The thin film 12 is warped and deformed due to residual compressive stress. 12. The recording liquid ejection of the printhead according to claim 11, wherein when the thin film 12 is martensitic, both ends thereof are fixed to the substrate 10 so that the thin film 12 is flexurally deformed around the space 11. Device The method according to claim 1, wherein the thin film 12 is heated to the austenite termination temperature or more to form an austenite structure, and becomes a flat plate, and when cooled below the martensite termination temperature to be converted into martensite structure, the thin film 12 is bent by magnetic force. The recording liquid jetting apparatus of the printhead, characterized in that it has a bidirectional deformation 15. The recording liquid jetting apparatus according to claim 14, characterized in that the thin film (12) is martensitic and applied with an external force several times to be learned, and then, upon cooling, the martensitic tissue is formed in a specific direction to have a desired displacement. The apparatus of claim 11, wherein the austenite finish temperature is about 60 ° C to 80 ° C, and the martensite end temperature is about 40 ° C to 60 ° C. 15. The apparatus of claim 14, wherein the austenite finish temperature is about 60 ° C to 80 ° C and the martensite end temperature is about 40 ° C to 60 ° C. 12. The recording liquid jetting apparatus of claim 11, wherein a time from heating to the austenite structure to cooling to the martensite structure is about 200 µsec or less and an operating frequency is 5 Hz or more. 15. The recording liquid jetting apparatus according to claim 14, wherein a time from heating to the austenite tissue to cooling to the martensite tissue is about 200 µsec or less and an operating frequency is 5 Hz or more.

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