JP4086461B2 - Inkjet head and inkjet printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inkjet head and an inkjet printer, and more specifically, an inkjet head that ejects ink from a nozzle by utilizing deformation of a magnetostrictive element, and an on-demand system that ejects ink with good controllability by using the inkjet head. The present invention relates to an inkjet printer.
The present invention is not limited to ink, and can be applied to an element that ejects liquid from a nozzle hole with good controllability and an apparatus using the element.
[0002]
[Prior art]
Conventionally, impact dot printers, etc., were often used as printers for output from information processing devices such as personal computers, but later changed to laser printers. Recently, on-demand inkjet printers have been demanded for low cost and colorization. Many printers are used.
A typical on-demand ink jet printer is a method in which ink is heated rapidly and ink is ejected by the pressure of ink volume change (for example, Japanese Patent Publication No. 61-59911), and voltage is applied. There is a method of ejecting ink using a piezoelectric body having a property of being deformed by doing so (for example, Japanese Patent Publication No. 2-51734).
[0003]
The piezoelectric system is characterized by good controllability of ink ejection, and a piezoelectric material is used for the head, and various configurations are well known. For example, a cylindrical piezoelectric element such as a vibrator cylindrical can is attached and ink is ejected by volume change when a voltage is applied to the piezoelectric element, or a flat vibrator is arranged outside the ink chamber and the voltage is There is a method of ejecting ink by changing the volume of the ink chamber when applying.
A conventional inkjet head using a piezoelectric element has an ink chamber having a nozzle at the tip, and is filled with ink. A vibration plate is provided outside the ink chamber, and a piezoelectric element is provided above the vibration plate. Electrodes are provided on both sides of the piezoelectric element, and the piezoelectric element is deformed by turning on and off the voltage applied to the electrode, and the bending deformation occurs due to the bimetallic effect between the piezoelectric element and the diaphragm, and the ink changes due to the volume change. Exhaled.
[0004]
Although there is a conventional technique using a magnetostrictive element instead of a piezoelectric element, there is no detailed specific report because the piezoelectric element can be simply replaced.
In addition, those using electrostatic force have been reported (for example, JP-A-7-81088). This principle utilizes a phenomenon in which when a voltage is applied to two flat plates, an electrostatic force acts between the flat plates to attract or repel each other. Those using electrostatic force are easy to simplify the structure, and can be manufactured using microfabrication processes such as semiconductors, which is advantageous for miniaturization. As a result, the phenomenon that the element breaks easily occurs, so that there is a drawback that the electrode interval is widened and precise control is required.
[0005]
[Problems to be solved by the invention]
As described above, an ink jet head using a piezoelectric element or electrostatic force has been reported. However, in a piezoelectric element, since the material of the piezoelectric element is generally ceramic, it is necessary to sinter at a high temperature when producing the element. Thus, there is a problem that there are restrictions on materials other than the vibrator. In addition, since it is a sintered body, there is a problem that it is difficult to adapt to a thin film process such as semiconductor processing, and the production becomes complicated.
In addition, in the case of an ink jet head using electrostatic force, the force becomes larger as the electrode interval becomes narrower. Therefore, it is advantageous that the electrode interval is narrower. There was a problem that it was necessary to control the electrode spacing.
[0006]
The problems of the conventional ink jet head as described above are solved by using a magnetostrictive material for the drive unit, and an ink jet head having a drive unit having a large deformation amount and generating force can be realized. However, since the magnetostrictive material needs to be excited, there has been a problem that an exciting portion such as a coil becomes large.
Accordingly, an object of the present invention is to realize an ink jet head and an ink jet printer that have a large deformation amount and generated force of the drive unit and are superior in controllability, power saving performance, productivity, and the like as compared with the conventional example. And
[0007]
[Means for Solving the Problems]
The present invention has been made in order to solve the above-mentioned problems, and the first technical means thereof uses a magnetostrictive element in a drive unit for ejecting ink, and constantly applies a magnetic field to the magnetostrictive element. And an ink jet head that ejects ink by causing the deformation to return the deformation by applying heat to the deformed magnetostrictive element.
[0008]
According to a second technical means, in the ink jet head of the first technical means, the magnetostrictive element is made of a compound containing Tb and Fe or a compound containing Sm and Fe .
[0009]
According to a third technical means of the present invention, in the ink jet head according to the first technical means, the magnetostrictive element has a property of extending in a direction parallel to the magnetic field by applying a magnetic field and a property of contracting in the direction parallel to the magnetic field. The fourth technical means is characterized in that the magnetostrictive element comprises a laminate of a compound containing Tb and Fe and a compound containing Sm and Fe .
[0010]
According to a fifth technical means of the present invention, in the ink jet head of the first to fourth technical means, the means for applying a magnetic field to the magnetostrictive element is a permanent magnet.
[0011]
According to a sixth technical means of the present invention, in the ink jet head of the fifth technical means, the permanent magnet is made of an SmCo-based alloy or an NdFeB-based alloy.
[0012]
According to a seventh technical means of the present invention, in the ink jet head of the first to sixth technical means , one or both of the magnetostrictive element and the permanent magnet are made of a thin film.
[0013]
According to an eighth technical means of the present invention, in the ink jet head of the first to seventh technical means, the means for applying heat to the magnetostrictive element is a heating element.
[0014]
According to a ninth technical means of the present invention, in the ink jet head of the first to seventh technical means, the means for applying heat to the magnetostrictive element is light or electromagnetic waves.
[0015]
A tenth technical means of the present invention is an ink jet printer using the ink jet heads of the first to ninth technical means as ink jet heads for ejecting ink.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on the examples shown in FIGS. The technical scope of the present invention is not construed as being limited in any way by the description of the examples.
(First embodiment)
The first embodiment corresponds to the invention of claim 1 and uses a magnetostrictive element as a drive unit for ejecting ink. In order to excite the magnetostrictive element, a magnetic field is applied to the magnetostrictive element to deform the magnetostrictive element. The present invention relates to an ink jet head that ejects ink by causing a change to return deformation by applying heat to a magnetostrictive element.
[0017]
Here, the magnetostriction is a property that causes a deformation such that a magnetic material expands or contracts when a magnetic field is applied, and a magnetic material has this property although there is a difference in degree. In particular, a material having a large amount of deformation is called a magnetostrictive material, which has been used for a long time as a vibrator for generating ultrasonic waves.
Examples of magnetostrictive materials include Ni, FeAl, FeCo, NiFe, NiCo, FeSi, FeB, FeSiB, FeCoSiB, FePd, and other alloy systems, and one or more of Fe, Ni, Co, Cu, etc. are mixed and sintered. There are also ferrite materials such as NiCo ferrite and NiCuCo ferrite produced by the above method.
Alloys such as FeB, FeSiB, and FeCoSiB have a relatively small amount of strain, but an electromechanical coupling coefficient indicating good conversion efficiency for converting electrical energy into mechanical energy is higher than that of a piezoelectric element. There is what is shown, and using these materials has a great effect.
Among ferrite materials, a magnetite-based material has a property that it operates well even when a strong pressure is applied to the material. In addition, the magnetostrictive material includes a material having a property of extending in a direction parallel to the applied magnetic field and a material having a property of contracting.
[0018]
FIG. 1 is a cross-sectional view schematically showing the periphery of a magnetostrictive element of an ink jet head according to a first embodiment of the present invention, which is an example using a magnetostrictive element having a property of contracting when a magnetic field is applied.
The ink jet head has a substrate 1, a diaphragm 2, a nozzle 3, a magnetostrictive element 4, a magnetic field applying means (not shown), and a heating means (not shown) as main components, and applies a magnetic field to the magnetostrictive element 4. And the ink in the ink chamber 5 is ejected from the nozzle 3 and ejected based on the deformation and the change that the deformation returns to the original state by heating by the heating means.
In the state of FIG. 1, no magnetic field is applied to the magnetostrictive element 4 and the magnetostrictive element 4 is not deformed, so the ink chamber 5 occupies a large volume. When the ink jet head of the first embodiment is used, since the magnetic field H is constantly applied to the magnetostrictive element 4, the magnetostrictive element 4 is deformed so that the length in the magnetic field direction is shortened, and as shown in FIG. Further, the diaphragm 2 is also deformed so that the volume of the ink chamber 5 is reduced. In this state, when the magnetostrictive element 4 is heated by the heating means and heated to a temperature equal to or higher than the Curie point, the state returns to the state shown in FIG.
A specific example of the heating means will be described later.
[0019]
Next, the principle of ejecting ink will be described.
FIG. 2 is a diagram showing a state in which the magnetic field H is applied to the magnetostrictive element 4 from the state of the ink jet head shown in FIG. 1, and the diaphragm 2 is deformed by the deformation of the magnetostrictive element 4 due to the application of the magnetic field H, and ink is ejected. The magnetostrictive element 4 immediately after that is in a contracted state.
Next, when heat is applied to the magnetostrictive element 4 from that state and the magnetostrictive element 4 is heated to the Curie temperature or higher, the magnetostrictive element 4 returns to the state before deformation, and the magnetostrictive element 4 and the diaphragm 2 are deformed as shown in FIG. Return to the state of the previous plane. At this time, ink is supplied into the ink chamber 5 from the supply port 6 and the ink chamber 5 is filled with ink.
When the temperature of the magnetostrictive element 4 drops when the ink chamber 5 is filled with ink, the magnetostrictive element 4 and the diaphragm 2 are deformed again as shown in FIG. 7 is injected.
The method for applying the magnetic field is not particularly limited.
Further, the magnetostrictive element 4 can be used alone instead of the diaphragm 2. In that case, the deformation can be further increased and the element can be miniaturized. In that case, it is more preferable to form a thin protective layer or the like on the surface where the magnetostrictive element 4 and the ink are in contact.
[0020]
(Second embodiment)
The second embodiment corresponds to the invention of claim 2, and as the magnetostrictive element 4, a material having a property of extending in a direction parallel to the magnetic field by applying a magnetic field H and a material having a property of contracting in the direction parallel to the magnetic field are laminated. It is related with the inkjet head used.
It is possible to increase the amount of deformation of the magnetostrictive element by laminating a material having the property of extending in a direction parallel to the magnetic field H and a material having a property of contracting in the direction parallel to the magnetic field H.
5 and 6 are diagrams showing the configuration of the magnetostrictive element 4 used in the ink jet head of the second embodiment. For example, by stacking TbFe and SmFe, they are parallel when no magnetic field is applied as shown in FIG. However, when a magnetic field H is applied as shown in FIG. 6, TbFe expands and SmFe contracts, causing deformation.
Since a large deformation can be obtained as compared with the case where each magnetostrictive element is used alone, it becomes easy to control ink ejection.
[0021]
(Third embodiment)
The third embodiment corresponds to the invention of claim 3 and relates to an ink jet head using a compound containing Tb and Fe or a compound containing Sm and Fe as the magnetostrictive element 4.
In a TbFe ₂ alloy having a so-called Laves phase such as a TbFe, SmFe alloy or the like, if the amount of elongation or contraction of the magnetic material when a magnetic field is applied in the length direction of the magnetic material of length L is ΔL, ΔL / L It is known that the displacement amount is as large as about 2000 × 10 ⁻⁶ . TbFe has a property of extending when a magnetic field is applied, and SmFe has a property of contracting.
Examples of the compound used in the magnetostrictive element of the present invention include alloy systems such as TbDyFe, TbDyHoFe, TbFeB, and SmFeB. A material having a small magnetocrystalline anisotropy while maintaining a large magnetostriction is preferred.
[0022]
The ink jet head of FIGS. 1 and 2 is made of a material having a property that the magnetostrictive element 4 contracts in a direction parallel to the magnetic field H when the magnetic field H is applied. In the example of FIGS. An example of an ink jet head using a material having a property of extending in a direction parallel to the magnetic field H when the magnetic field H is applied is shown.
In the state of FIG. 3 in which the magnetic field H is applied to the magnetostrictive element 4, the magnetostrictive element 4 is stretched and deformed, and the diaphragm 2 is also deformed accordingly, and the ink chamber 5 whose volume is increased is filled with ink. .
The principle of ejecting ink is almost the same as that shown in the first embodiment of FIGS. 1 and 2, and the diaphragm 2 is deformed by the deformation of the magnetostrictive element 4, and is deformed by a heating means (not shown). When the magnetostrictive element 4 is heated to the Curie temperature or higher, the ink in the ink chamber 5 is pushed out from the nozzle 3 and ejected.
[0023]
The principle of ejecting ink when a TbFe ₂ alloy is used as the compound containing Tb and Fe will be described.
As shown in FIG. 3, in a state immediately after ink is ejected, the magnetostrictive element 4 is deformed by applying a magnetic field H and extending. In this state, ink is supplied from the supply port 6 and the ink chamber 5 is filled with ink.
Next, when heat is applied to the magnetostrictive element 4 from that state and the temperature becomes equal to or higher than the Curie temperature, the magnetostrictive element 2 and the diaphragm 4 return to the plane state before deformation as shown in FIG. At this time, the ink in the ink chamber 7 is ejected from the extrusion nozzle 3 as ink droplets 7.
The method for applying the magnetic field is not particularly limited. It is also possible to eliminate the diaphragm 4 and use the magnetostrictive element 2 alone as a diaphragm. In that case, the deformation can be further increased and the element can be miniaturized. In this case, it is more preferable to form a thin protective layer on the surface where the magnetostrictive element 2 and the ink are in contact.
When SmFeB is used as the compound containing Sm and Fe, the ink is ejected by repeating the deformation of FIGS. 1 and 2 as described in the first embodiment.
[0024]
(Fourth embodiment)
The fourth embodiment corresponds to the invention of claim 4 and relates to an ink jet head using a permanent magnet as means for applying a magnetic field to the magnetostrictive element.
A magnetic field can be generated using a coil as a means for generating the magnetic field H applied to the magnetostrictive element 4, but a permanent magnet is used to further reduce power consumption, and the magnetic field generated therefrom is used to drive the magnetostrictive element. Use.
FIG. 7 is a plan view of the magnetostrictive element 4 as viewed from above. Permanent magnets 8 and 8 are arranged on both sides of the magnetostrictive element 4 so that the magnetic field H is applied.
Further, as shown in FIG. 8, the magnetic circuit can be closed by disposing the soft magnetic material 9 on the upper surface or the lateral surface of the magnetostrictive element 4, and the magnetic field H can be efficiently applied to the magnetostrictive element 4. This is preferable.
[0025]
(5th Example)
The fifth embodiment corresponds to the invention of claim 5 and relates to an ink jet head using SmCo alloy or NdFeB alloy as permanent magnets 8 and 8 for exciting a magnetostrictive element.
The SmCo-based alloy has an advantage that the magnet is strong and the Curie temperature is high, so that it is also resistant to temperature.
Further, since the NdFeB alloy has the strongest magnetic force as a magnet, a strong magnetic field can be applied.
Moreover, what added the element to these alloys is also developed. Recently, it has become clear that nitrides and carbides such as SmFeN have a strong magnetic force, and their alloy systems are also applicable.
Further, in order to prevent performance deterioration due to magnet corrosion or the like, it may be covered with a protective film or the like.
[0026]
Here, an example using an SmCo ₅ alloy is shown.
FIG. 9 is a schematic plan view of the magnetostrictive element 4 used in the ink jet head of the fifth embodiment. SmCo ₅ alloys are arranged as permanent magnets 8a and 8a on both sides of the magnetostrictive element 4a made of SmFe ₂ , and the permanent magnet is shown. Each element was configured such that a closed magnetic circuit was formed using a NiFe alloy or the like as the soft magnetic material 9a so that a magnetic field was efficiently applied to 8a, 8a and the magnetostrictive element 4a.
[0027]
(Sixth embodiment)
The sixth embodiment corresponds to the invention of claim 6 and relates to an ink jet head in which a magnetostrictive element and / or a permanent magnet is made of a thin film.
FIG. 10 is a diagram showing a schematic cross section of the ink jet head of the sixth embodiment. The magnetostrictive element 4 or the permanent magnets 8b and 8b, or both the magnetostrictive element 4b and the permanent magnets 8b and 8b are made of a thin film. .
By producing a magnetostrictive element and a permanent magnet with a thin film, process technology such as photolithography can be applied, and the production method becomes easy.
[0028]
(Seventh embodiment)
The seventh embodiment corresponds to the invention of claim 7, and relates to an ink jet head using a heating element as a heating means for applying heat to the magnetostrictive element.
FIG. 11 is a schematic plan view of the magnetostrictive element 4 used in the ink jet head of the seventh embodiment. A heating element 10 is provided in the vicinity of the magnetostrictive element 4, and the temperature is raised by passing a current through the heating element 10. The magnetostrictive element 4 is driven by making the temperature equal to or higher than the Curie temperature. A TbDyFeB amorphous alloy is used as the magnetostrictive element 4. Since the heating element 10 can be composed of only heater wires, an ink jet head having a simple configuration can be formed.
[0029]
(Eighth embodiment)
The eighth embodiment corresponds to the invention of claim 8 and relates to an ink jet head using light or electromagnetic waves as means for applying heat to the magnetostrictive element.
By irradiating the magnetostrictive element 4 with light such as a laser, the energy of the light is converted into heat, and the magnetostrictive element is brought to a Curie temperature or higher. The temperature of the magnetostrictive element 4 is controlled by light and driven.
FIG. 12 is a diagram showing a schematic cross section of the ink jet head of the eighth embodiment. The magnetostrictive element 4 is irradiated with the laser light emitted from the laser diode 11 and the energy thereof is changed to heat. To drive. By using light such as a laser, the driving means can be configured away from the magnetostrictive element 4, and the light has a quick response and is suitable for high-speed driving.
[0030]
(Ninth embodiment)
The ninth embodiment corresponds to the invention of claim 9 and relates to an ink jet printer using the ink jet heads of the first to ninth embodiments as ink jet heads for ejecting ink.
FIG. 13 is a side sectional view showing a schematic configuration of the ink jet printer.
In this ink jet printer, the paper 22 delivered from the paper feed cassette 21 is conveyed by the paper feed roller 23, and further, the image is recorded on the paper 22 by the recording head 25 composed of an ink jet head while the paper 22 is being conveyed by the conveying unit 24. The paper is discharged to the paper discharge tray 26.
A sensor 27 and a sensor 28 for detecting the presence or absence of the paper 22 and detecting the type of the paper 22 are arranged downstream of the paper feed roller 23. Here, the sensor 27 and the sensor 28 can be transmissive photosensors, but are not limited to this, and various other detection means such as other optical and mechanical types can be used.
[0031]
【The invention's effect】
As is clear from the above description, the present invention has the following effects.
(1) According to the invention of claim 1, since the drive part of the inkjet head is formed by a magnetostrictive element, a magnetic field is applied to the magnetostrictive element, and the magnetostrictive element is heated to drive it. Thus, an ink jet head excellent in controllability, power saving and productivity can be realized.
[0032]
(2) According to the invention of claim 2, since the magnetostrictive element uses a laminate of a magnetostrictive element material that extends in a direction parallel to the magnetic field and a magnetostrictive element material that contracts in a direction parallel to the magnetic field when a magnetic field is applied. In comparison with the case where the magnetostrictive element material is used alone, a large deformation can be obtained, so that the ink ejection control is easy.
[0033]
(3) According to the invention of claim 3, since a compound containing Tb and Fe or a compound containing Sm and Fe is used as the magnetostrictive element, the volume change of the ink chamber of the inkjet head can be increased, and the amount of ink ejected Controllability is improved.
[0034]
(4) According to the invention of claim 4, since the means for applying a magnetic field to the magnetostrictive element is a permanent magnet, it is possible to save power consumption.
[0035]
(5) According to the invention of claim 5, since the permanent magnet is made of an SmCo alloy or an NdFeB alloy, a larger driving force can be obtained.
[0036]
(6) According to the invention of claim 6, since the magnetostrictive element and the permanent magnet are made of a thin film, it is possible to apply a simpler process in producing the ink jet head.
[0037]
(7) According to the seventh aspect of the present invention, since the heating means of the magnetostrictive element is a heating element, the structure of the element can be made relatively simple, and a large driving force can be obtained even with the simple structure.
[0038]
(8) According to the invention of claim 8, since the heating means of the magnetostrictive element is light or electromagnetic wave, the controllability with respect to the driving of the element is improved and the controllability of the ink ejection amount and the like is improved.
[0039]
(9) According to the ninth aspect of the invention, since the drive unit uses an ink jet head having a magnetostrictive element, the ink jet printer is excellent in controllability, power saving and productivity with a new configuration different from the conventional one. Is feasible.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a configuration in a case where a magnetostrictive element of a driving unit is made of a material that contracts when a magnetic field is applied in an ink jet head according to a first embodiment.
FIG. 2 is a schematic cross-sectional view when the ink jet head shown in FIG. 1 ejects ink.
FIG. 3 is a schematic cross-sectional view showing a configuration in the case where the magnetostrictive element of the drive unit is a material having a property of extending when a magnetic field is applied in the ink jet head of the first embodiment.
4 is a schematic cross-sectional view when the ink jet head shown in FIG. 2 ejects ink. FIG.
FIG. 5 is a schematic diagram showing a laminated state of magnetostrictive elements made of a laminated body of SmFe and TbFe alloy in the ink jet heads of the second and third embodiments.
6 is a schematic diagram showing a laminated state of SmFe and TbFe alloy when a magnetic field is applied to the magnetostrictive element shown in FIG.
FIG. 7 is a schematic plan view showing magnetic field applying means using a permanent magnet in the ink jet head of the fourth embodiment.
8 is a schematic plan view showing magnetic field applying means in which a magnetic circuit is formed on the permanent magnet shown in FIG.
FIG. 9 is a schematic plan view showing magnetic field applying means using a permanent magnet made of an SmCo alloy or NdFeB alloy in an ink jet head of a fifth embodiment.
FIG. 10 is a schematic view of a cross section of an inkjet head using magnetostrictive elements and permanent magnets made of a thin film in the inkjet head of the sixth embodiment.
FIG. 11 is a schematic plan view showing a magnetic field applying unit including a heating unit made of a heating element in an ink jet head of a seventh embodiment.
FIG. 12 is a schematic sectional view showing an ink jet head provided with heating means using light in the ink jet head of the eighth embodiment.
FIG. 13 is a schematic sectional view of an ink jet printer according to a ninth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Diaphragm, 3 ... Nozzle, 4, 4a, 4b ... Magnetostrictive element, 5 ... Ink chamber, 6 ... Supply port, 7 ... Ink drop, 8, 8a, 8b ... Permanent magnet, 9, 9a ... Soft magnetic material, 10 ... heating element, 11 ... laser diode, 21 ... feed cassette, 22 ... paper, 23 ... roller, 24 ... conveying section, 25 ... recording head, 26 ... discharge tray, 27 ... sensor, 28 ... Sensor.

Claims (10)

A magnetostrictive element is used in the drive unit for ejecting ink, and a magnetic field is constantly applied to the magnetostrictive element to deform the magnetostrictive element, and heat is applied to the deformed magnetostrictive element to cause a change to return the deformation. An ink jet head characterized by ejecting the ink. The inkjet head according to claim 1, wherein the magnetostrictive element is made of a compound containing Tb and Fe or a compound containing Sm and Fe.   2. The ink jet head according to claim 1, wherein the magnetostrictive element is a laminate of a material having a property of extending in a direction parallel to a magnetic field when a magnetic field is applied and a material having a property of contracting in a direction parallel to the magnetic field. The magnetostrictive element, an ink jet head according to claim 3, characterized in that a laminate of a compound comprising a compound and Sm and Fe containing Tb and Fe. It said means for applying a magnetic field to the magnetostrictive element, according to claim 1 to 4 inkjet head according to any one characterized in that it is a permanent magnet. 6. The ink jet head according to claim 5 , wherein the permanent magnet is made of an SmCo alloy or an NdFeB alloy. Said magnetostrictive element and one or both of the permanent magnet, according to claim 1 to 6 inkjet head according to any, characterized in that to produce a thin film. It said means for applying heat to the magnetostrictive element, an ink jet head according to any one of claims 1 to 7, characterized in that a heating element. It said means for applying heat to the magnetostrictive element, an ink jet head according to any one of claims 1 to 7, characterized in that a light or electromagnetic wave. Inkjet heads for ejecting ink-jet printer which is a ink-jet head according to any one of claims 1 to 9.

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