JPH10286952A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control deformations of each of vibrating plates which are obtained by dividing a single vibrating plate with a high degree of freedom. SOLUTION: This ink jet recording head is equipped with nozzle holes 5, a pressure chamber 10 communicating with each of the nozzle holes 5, a vibrating plate 11 provided on the wall face of the pressure chamber 11 and opposite electrodes against, across a specified distance, the vibrating plate 11. In addition, the ink jet recording head is of such a functional construction that the vibrating plate 11 is deformed by applying voltage to a space between the vibrating plate 11 and the opposite electrodes and thereby, an ink droplet is discharged from the nozzle holes 5. In this case, at least, a first and a second opposite face 14, 15 and a first and a second individual electrode 12, 13, positioned independently of each other are provided which are opposed to the vibrating plate 11 with at least, a first gap level and a second gap level which is higher than the first gap level and with which the vibrating plate 11 can be brought into contact at the time of its deformation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head which deforms a diaphragm by using an electrostatic force generated when a voltage is applied to an electrode arranged at a predetermined distance from the diaphragm. More specifically, the present invention relates to an ink jet recording head which improves the capability of ejecting large ink droplets, ejecting small ink droplets, and both, or improving responsiveness and ink droplet flight characteristics.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 2-289351 discloses an ink jet recording head in which electrodes are arranged at a slight distance from a diaphragm forming a pressure chamber, and the diaphragm is deformed by electrostatic force to discharge ink droplets. JP-A-6-239
No. 80, JP-A-7-246706, JP-A-7-214
No. 769, JP-A-8-290567, JP-A-8-72
No. 240, JP-A-9-39228, JP-A-9-392
It is described in each gazette of No. 35. In particular, the last two cases describe the contents closest to the present invention.

However, high-quality color printing comparable to silver halide photography can be performed, and high-speed printing can be performed with high response, gradation recording, high-density ink can be used, and the amount of ejected ink droplets can be increased. However, with respect to the requirement that the flight position be highly accurate, the above-described conventional structure is still insufficient in its degree of freedom and reliability.

[0004]

With this type of head,
When the voltage between the diaphragm and the counter electrode exceeds a certain threshold value, the diaphragm starts to deform, and when the voltage exceeds a certain threshold value, the deformation returns. For example, in Japanese Unexamined Patent Publication No. 9-39235, a small gap, a medium gap Even if only the diaphragm is brought into contact with the opposing surface, the diaphragm is already approaching the counter electrode even in the large gap, so that the diaphragm is pulled or abutted on the counter electrode even in the large gap. Also, when returning the diaphragm, a method is described in which the slope of the voltage drop is gradual in order to gradually return the diaphragm.However, when the voltage exceeds a certain threshold value, the diaphragm returns depending on the elastic characteristics of the diaphragm. However, in reality, the voltage does not return according to the slope of the voltage drop, and the return speed cannot be sufficiently controlled. In consideration of the variation in the elastic force and the variation in the gap of the diaphragm, it becomes increasingly difficult to control the deformation amount and the deformation speed of the diaphragm with only one voltage waveform.

The present invention has been made in view of such a problem, and an object of the present invention is to make it easy to control the amount of deformation and the deformation speed of a diaphragm. It is an object of the present invention to secure the ink jet recording head and to stably impart control performance to the meniscus, and to realize such an ink jet recording head.

[0006]

In order to solve the above-mentioned problems, an ink jet recording head according to the present invention is provided with a plurality of nozzle holes, a pressure chamber communicating with each of the nozzle holes, and a wall provided on the pressure chamber. Provided with a counter electrode facing the diaphragm at a predetermined distance, applying a voltage between the diaphragm and the counter electrode, deforming the diaphragm, In an ink jet head for ejecting ink droplets, at least a first gap amount and a second gap amount larger than the first gap amount are opposed to the vibration plate, and the vibration is generated when the vibration plate is deformed. 1st, 2nd that the board can abut
, And first and second individual electrodes independent of each other are provided corresponding to the first and second gap amounts.

[0007]

[Operation] As a result, by providing a plurality of gap amounts represented by the second gap amount and corresponding individual electrodes,
The deformation amount and the deformation speed of the diaphragm can be controlled with a high degree of freedom in a manner following the voltage waveform applied to the individual electrode.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments.

FIG. 1 is an external view of an embodiment of an ink jet recording head according to the present invention. Reference numeral 2 denotes a nozzle plate, on the surface of which is provided two rows of nozzle holes 5. Reference numeral 3 denotes a flow path forming substrate including a pressure chamber or the like communicating with the nozzle hole 5, reference numeral 4 denotes an opposing substrate laminated on the flow path forming substrate 3, and reference numeral 6 denotes a flexible cable for applying a voltage signal. is there. Reference numeral 7 denotes a case member that holds the opposing substrate 4 and is attached to the carriage of the printer. The case member also has an ink supply path to the flow path forming substrate. Ink is supplied to the ink chamber in the flow path forming substrate from the lower side of the figure through a path such as a needle.

FIG. 2 is an exploded perspective view of a main part of the ink jet recording head according to the present invention. FIG. 3 is a sectional view of the pressure chamber portion cut in a longitudinal direction. FIG. It is sectional drawing at the time of cutting along the aa of arrangement direction.

The nozzle plate 2 has nozzle holes 5 arranged in two rows. Reference numeral 8 denotes a recess provided so that the periphery of the nozzle hole 5 is slightly depressed. In the concave portions formed in the flow path forming substrate 3, reference numeral 9 denotes a common ink chamber, and reference numeral 10 denotes a pressure chamber. One wall surface of the pressure chamber 10 is a thin diaphragm 11.

On the surface of the counter substrate 4, there is provided a recess 28 for providing a minute gap with respect to the diaphragm 11, and this recess 28 is formed in two steps in this embodiment. Thin electrode films 12 and 13 are formed on the surface of the recess 28. The number of steps in the depth of the recess 28 and the formation of more electrodes are significant, as will be understood from the following description.

The nozzle plate 2, the flow path forming substrate 3, and the opposing substrate 4 are laminated, the nozzle plate 2 forms one wall surface of the ink chamber 9 and the pressure chamber 10, and the nozzle hole 5 communicates with the pressure chamber 10. The plate 11 has individual electrodes 12 on the counter substrate 4,
13 face each other.

The thickness of the nozzle plate 2 is approximately 0.05 to
0.13mm, nozzle hole arrangement pitch is 0.141mm
It is. The material is a thin plate material such as a metal such as stainless steel, ceramic, plastic, or glass. The nozzle hole can be formed by electroforming, chemical etching, dry etching, laser processing, molding, punching, or the like, and it is important to appropriately select a method suitable for the material. The diameter of the nozzle hole is selected so as to have a proper ejection speed with respect to the amount of ink droplet to be ejected, but empirically, the ink droplet amount is 20 to 50 ng and the diameter is approximately 30 to 40 μm.

The flow path forming substrate 3 has a thickness of 0.2 to 0.5 m.
m is obtained by anisotropically etching a silicon substrate. After forming a boron-doped layer which is an etching-resistant layer on one surface of a silicon substrate, it is selectively etched from the other surface using a thermal oxide film as a mask to form a recess which becomes a pressure chamber 10 or an ink chamber 9 having a width of 0.1 mm. Then, the remaining boron-doped layer becomes the vibrating plate 11, and the flow path forming substrate 3 integrated with the vibrating plate is completed. After removing the thermal oxide film used as the mask after the etching, thermal oxidation is performed again to cover the inner and outer wall surfaces with the oxide film. The oxide film on the diaphragm functions as an insulating film. The thickness of the diaphragm 11 is approximately 1 to 2 μm including the oxide film.
m, design optimally according to the discharge target.

The diaphragm may be formed of a separate member.
In that case, after the diaphragm is formed, it is attached to the flow path forming substrate. Alternatively, a diaphragm is formed on the flow path forming substrate. When the diaphragm is formed of a separate member, the choice of materials for the flow path forming substrate and the diaphragm is expanded. In addition, a photosensitive resin, ceramic, or the like can be used as the flow path forming substrate, and a metal, a resin film, or ceramic can be used for the diaphragm.

The opposing substrate 4 is made of glass having a thickness of 1 to 3 mm, and the recess 28 on the surface is formed by etching. After an oxide conductive film such as ITO or a conductive film such as gold is sputtered thereon, patterning is performed by etching to function as opposing individual electrodes. The thickness of the opposing individual electrode is 0.1 μm.

Silicon can be used as the counter substrate 4, and other fine recesses can be processed with high precision.
Other materials that can be joined to the diaphragm can also be used.

The nozzle plate 2, the flow path forming substrate 3, and the counter substrate 4 are laminated and integrated by applying a precision bonding technique such as adhesive, brazing, and anodic bonding.

The recess 28 formed in the counter substrate 4 of the present embodiment.
Are only 0.3 μm and 0.5 μm, respectively, and the thickness of the individual electrodes 12 and 13 formed thereon is 0.1 μm as described above. Therefore, the first gap amount g1 is 0.2 μm.
m, and the second gap amount g2 is 0.4 μm. In this embodiment, the surfaces of the individual electrodes 12 and 13 are also contact surfaces that the diaphragm 11 can contact when deformed. An insulating film may be formed on the individual electrodes 12 and 13, which is more preferable in terms of reliability. At this time, the surface of the insulating film becomes a contact surface to which the diaphragm 11 can contact when deformed.

For the gap amounts g1 and g2, g1 ≧ g2-g
1 is desirable. This is because, as can be understood from the following description, the diaphragm in the gap amount g2 portion has a small area and therefore is less likely to be deformed than the diaphragm in the gap amount g1 portion, and also to alleviate the stress applied to the diaphragm. .

The first gap g1 of the diaphragm 11
The diaphragm part opposing with the diaphragm <first> and the diaphragm part opposing with the second gap amount g2 are the diaphragm <second>
>.

The individual electrodes 12 and 13 are drawn out to the end of the opposing substrate 4 and connected to the flexible cable 6 via an anisotropic conductive film. On the other hand, a common electrode 18 is formed by removing an oxide film on a part of the flow path forming substrate 3 made of silicon to form a common electrode 18 provided with a metal film, and then connected to the flexible cable 6 in the same manner. FIG. 5 is a pattern plan view showing an example of the shape of the opposing individual electrodes 12 and 13.

Next, the deformation operation of the diaphragm will be described with reference to FIGS. The diaphragm 11 in the flat state shown in FIG. 6A has electrodes 12 and 13 based on a recording signal.
When applying voltage waveforms 23 and 53 as shown in FIGS. 7A and 7C, respectively, first, when the threshold voltage V1 determined by the rigidity of the diaphragm and the gap amount g1 is reached, FIG. Thus, the diaphragm <1> is deformed, and then the diaphragm <2> whose gap amount is reduced due to the deformation is deformed as shown in FIG. 6 (c) by the voltage 53a which rises with a delay. FIG. 7
(B) shows the maximum deformation amount of the diaphragm 11. After holding for a short appropriate time determined by the pressure oscillation cycle, the voltage release 53c
When the threshold voltage V3 is passed in the process, the diaphragm <second>
Next, voltage release 23 which is started at a required timing
When the threshold voltage V4 is passed in the process of c, the diaphragm <first>
Is returned to the position shown in FIG. 6A by the elastic force. The return of the vibration plate 11 increases the ink pressure in the pressure chamber 10 and ejects ink droplets from the nozzle holes 5.

Conventionally, only a deformation speed which tends to depend on the elastic characteristics of the diaphragm can be obtained.
The deformation amount and the deformation timing can be freely determined by dividing into the gap amount g2 and the first gap amount g1. For example, the average deformation speed can be controlled by the magnitude and timing of the voltage waveform for application and release.

Of course, the slope and pulse width of each voltage waveform,
The voltage and the application timing can be set independently. Further, if the gaps are designed to have the third, fourth,... Gap amounts, the degree of freedom increases and the deformation amount in a large range,
It can be understood that the deformation speed can be controlled, and the present invention includes such a structure. Since the first and second gaps are arranged in the longitudinal direction of the pressure chamber, a large amount of deformation can be obtained without lowering the nozzle arrangement density (pitch between nozzles).

Next, another embodiment will be described with reference to FIGS. After the opposing individual electrodes 12 and 13 are separated so that a signal can be applied independently, a voltage as shown in FIG. 8A is applied to the individual electrode 12 in advance to bring the diaphragm <first> into the opposing surface. (FIG. 9)
(B)). The application timing of the voltage 24a may be any time before it does not affect the subsequent ink droplet ejection. In this state, when the recording signal is received, the voltage waveform 2 is applied to the individual electrode 13.
5a is applied to deform the diaphragm <second> (FIG. 9).
(C)) After holding for a certain short appropriate time determined by the pressure oscillation cycle and then releasing the voltage as in 25c, the diaphragm <second
Is restored (FIG. 9B)), and a small ink droplet is ejected only by the deformation operation of the diaphragm <Second>.

In the conventional example, since there is one electrode, the operation of the diaphragm <second> is not separated, and the diaphragm <first>
The diaphragm <second> is deformed with the contact of <>, and the worst contact occurs. When the diaphragm <second> is released from deformation, the diaphragm <first> also separates from the facing surface, and the diaphragm <
It is not possible to achieve the idea of operating only the diaphragm <second> while securing the first>.

However, according to the present invention, in an ink jet recording head capable of ejecting a large ink droplet by using the entire diaphragm, a part of the diaphragm 11 is used independently.
Moreover, the target small ink droplet can be ejected in a state where the diaphragm portion that does not contribute to ejection is securely fixed to the facing surface so as to reduce compliance. For example, small ink droplets of 10 ng or less can be ejected at a high speed of 7 m / s or more.

Next, another embodiment will be described with reference to FIGS. After separating the opposing electrodes 12 and 13 so that signals can be applied independently, the individual electrodes 12
In advance, a voltage as shown at 26d in FIG. 10 is applied in advance to deform the diaphragm <1> so as to abut on the facing surface (FIG. 11).
(A)). When the recording signal is received in that state, if the voltage waveform 27a is applied to the individual electrode 13, the diaphragm <second> is deformed (FIG. 11B). , 26c, 27c (both waveforms drop in voltage at the same timing), the diaphragm <first> and the diaphragm <second> are caused by the elastic force of FIG. Then, the ink pressure in the pressure chamber 10 increases and ink droplets are ejected from the nozzle holes 5. After the ink droplets are ejected, the meniscus repeats residual vibration, but the residual vibration is canceled. At a certain timing, a voltage 26a for deforming the diaphragm <1> so as to contact the opposing surface is applied to the individual electrode 12 (FIG. 11A), and thereafter, this cycle is repeated every time a recording signal is received.

The method relating to the meniscus control has already been proposed by the present applicant in an ink jet type recording head using a piezoelectric element as a pressure generating source. According to the method, first, the diaphragm <first> can be reliably brought into contact with the diaphragm <second> without instably affecting the diaphragm <second> by the application of the signal 26d, and in this state, only the diaphragm <second> receives The shape of the meniscus before the ejection can be made constant regardless of the driving frequency by being deformed by 27a. As described above, the return of the diaphragm at the time of ink droplet ejection can be optimized with a high degree of freedom by using both voltage waveforms. After the ejection, the residual vibration of the meniscus can be suppressed only by the voltage applied to the individual electrode 12, the unnecessary satellite drop can be eliminated, and the meniscus can be attenuated at an early stage. It can be prepared for a recording signal. According to this embodiment, stable ejection and high response can be achieved such that the ejection ink droplet reaches 30 ng and 30 KHz.

Next, an effective embodiment for suppressing a local increase in the ink viscosity in the nozzle hole 5 at rest will be described with reference to FIGS.

The voltage waveform 29 shown in FIG.
, The diaphragm <first> is deformed (FIG. 13).
By repeating (b)) and return (FIG. 13 (a)), a minute swing of the meniscus can be caused in the nozzle hole. In addition, the gap amount g1 and the area of the diaphragm <first> are set so that the ink droplets are not ejected and only a slight swing of the meniscus is caused.
It goes without saying that the voltage is optimally set.

Before starting ejection of ink droplets for recording,
After diffusing the high-viscosity ink that has risen in the nozzle hole by the oscillating voltage waveform 29 of at least one pulse, preferably 10 pulses or more, the diaphragm <1> stands by in a deformed state (FIG. 13B). . When the recording signal is input, the voltage signal 30 is applied to the individual electrode 13, and the diaphragm <second> is deformed (FIG. 13C), and then the voltage drops 31c and 30c
(Here, both voltage drops have the same timing, but 31c may be delayed in order to slow down the deformation speed.)
As a result, the diaphragm <first> and the diaphragm <second> return,
The ink pressure in the pressure chamber 10 increases, and ink droplets are ejected from the nozzle holes 5. Thereafter, the voltage 31a for canceling the residual vibration of the meniscus is applied to the individual electrode 12 as in the previous embodiment, and the standby state shown in FIG.

The method relating to the meniscus oscillation has already been proposed in an ink jet recording head using a piezoelectric element as a pressure source, but this type of head handled by the present invention does not lead to ejection during standby. However, it has been difficult to perform control so that ejection can be performed when a recording signal enters while giving only the swing of the meniscus. However, according to the above-described recording head of the present invention, the signal for meniscus oscillation and the ejection signal can be operated independently. Diaphragm <No.
When the diaphragm <1> is deformed small and the meniscus swings in the free state of <2>, the diaphragm <1> deforms slowly because the compliance of the diaphragm is large. Also, the ink pressure does not increase. Even if the ink has a high concentration, the increase in viscosity can be suppressed, and necessary ejection can be performed with the increase in viscosity suppressed.

FIG. 14 shows an application example of another ejection operation of the ink jet recording head according to the present invention. FIG. 14 shows a voltage waveform (an upper side shows a voltage waveform applied to the first individual electrode, and a lower side shows a voltage waveform applied to the second individual electrode). (Showing a voltage waveform applied to the diaphragm). Voltage waveform 32 (32
After the diaphragm <first> is deformed by a, b, c) to give a slight swing to the meniscus, the diaphragm <first> maintains the deformed state in the section 33b. Waveforms 34a, b, c and 33
In step c, the diaphragm <second> is deformed, and the diaphragm <first, second> returns to eject a large ink droplet, and again in section 35b, the diaphragm <
The first> returns to the deformed state, and in the waveforms 36a, b, and c, the diaphragm <second> deforms to discharge small ink droplets. Thereafter, the waveforms 32, 33, 35 and 34, 3
This cycle is repeated while 6 is selectively applied.

This method selectively performs meniscus minute vibration, small ink droplet ejection, and large ink droplet ejection during a printing operation in accordance with a recording signal, and provides a plurality of individual electrodes for one diaphragm. It was realized in.

FIG. 15 shows another embodiment of the counter substrate 4 of the ink jet recording head according to the present invention, and FIG. 16 (a) is a sectional view thereof. The individual electrode 42 is common to each pressure chamber. Therefore, if a voltage is applied to the electrode 42, the diaphragm <first> of all the pressure chambers arranged in a row can be deformed (FIG. 16 (b)). When the voltage waveforms shown in FIGS. 10 and 12 are applied to the electrodes 42 and 13,
1, the same operation as in FIG. 13 can be performed. For example, in the case of a minute vibration of the meniscus, it is possible to carry out all the nozzles simultaneously.

According to this structure, the wiring from the counter electrode can be omitted, the input terminal can be omitted, and the area required for the electrode can be reduced. It is also effective in reducing the number of pins and the area of the driving integrated circuit.

FIG. 17 shows still another embodiment of the ink jet recording head of the present invention, and is a cross-sectional view when cut along the longitudinal direction of the pressure chamber. FIG.
8 is a plan view of the pattern of the individual electrodes facing each other.

A second gap is provided at the center in the longitudinal direction of the pressure chamber, and a first gap is provided on both sides thereof. The deformation operation of the diaphragm is the same as described above. Since the gap amount is symmetrically arranged so as to match the bending shape of the diaphragm 11, the stress of the diaphragm can be reduced.

FIG. 19 shows still another embodiment of the ink jet recording head of the present invention. FIG. 19 (a) is a sectional view taken along the longitudinal direction of the pressure chamber, and FIG.
FIG. 9B is a sectional view when cut along the direction in which the pressure chambers are arranged. There is a projection 16 protruding from the counter substrate 4 in the direction of the diaphragm 11, and a first gap amount g1 is formed between the tip surface of the projection and the diaphragm. The first gap g1 is 0.1 μm, the second gap g2 is 0.2 μm, and the projection height is 0.1 μm from the surface of the electrode 12. Individual electrodes 12, 1
3 and a voltage as shown at 24a in FIG.
> Can be deformed so as to abut on the facing surface (FIGS. 20A and 20B).

According to this embodiment, the diaphragm 11 and the individual electrode 1
3 and the distance between the individual electrodes 12 are the same, and there is no effect of increasing the maximum deformation amount. However, as in the previous embodiment, the amount of deformation of the diaphragm 11 can be controlled in two stages corresponding to the gap amounts g1 and g2. Further, since there is no need to provide a step between the individual electrodes 12 and 13, the opposing surface of the opposing substrate 4 and the electrodes are easily formed.

FIG. 21 shows still another embodiment of the ink jet recording head of the present invention. FIG. 21 (a) is a sectional view taken along the longitudinal direction of the pressure chamber, and FIG.
FIG. 1B is a cross-sectional view when cut along the direction in which the pressure chambers are arranged. There is a protrusion 17 protruding from the vibration plate 11 in the direction of the counter substrate 4, and forms a first gap between the protrusion surface and the counter surface. The first gap amount g1 is 0.1 μm,
The second gap g2 is 0.2 μm, and the height of the protrusion is 0.1 μm from the diaphragm surface. After the signal can be applied to the individual electrodes 12 and 13, the individual electrodes 12
By applying a voltage as shown in (1), the diaphragm <first> can be deformed so as to be in contact with the facing surface.

As in the above-described embodiment, the amount of deformation of the diaphragm 11 can be controlled in two stages corresponding to the gap amounts g1 and g2. Further, since there is no need to provide a step between the individual electrodes 12 and 13, the opposing surface of the opposing substrate 4 and the electrodes are easily formed.

The height of the projection is only 0.1 μm, and the projection can be formed by forming a film on the surface of the diaphragm by sputtering and patterning the film by etching.

FIG. 22 shows another embodiment of the ink jet recording head according to the present invention. The diaphragm 11 is a pressure chamber 10
The counter substrate 4 is composed of a laminate composed of boron-doped silicon, a silicon oxide film, individual electrodes, and an insulating film from the side.
The electrodes formed on the diaphragm 11 were formed as common electrodes, the individual electrodes 52 and 53 were formed on the diaphragm 11 so as to face the common electrodes, and the electrodes 52 were common to the pressure chambers. The step is provided in the recess 28 on the surface of the counter substrate 4 so as to have the first and second gap amounts as in the previous embodiment. Individual electrodes 52, 53
Is formed by applying a conductive oxide film or a metal film and then patterning by a photolithography technique, and the insulating film is formed by sputtering silicon oxide.

FIG. 23 is a sectional view of still another embodiment of the ink jet recording head according to the present invention, in which individual electrodes 52 and 53 are provided on the diaphragm 11 and a step is provided on the surface thereof to form a first gap g1. And a second gap amount g2. The configuration and operation can be understood from the above description.

The present invention has been described in detail with reference to the embodiments. The basic principle and manufacturing method of ink droplet ejection are also described in the above-mentioned patent publication, and any unknown points can be supplemented.

[0050]

As described above, according to the present invention, a plurality of nozzle holes, a pressure chamber communicating with each of the nozzle holes, a diaphragm provided on the wall surface of the pressure chamber, An inkjet head comprising a counter electrode facing at a predetermined distance, applying a voltage between the diaphragm and the counter electrode to deform the diaphragm, and ejecting ink droplets from the nozzle holes. An opposing surface that can face the diaphragm with at least a first gap amount and a second gap amount larger than the first gap amount, and that the diaphragm can abut when the diaphragm is deformed. Since the first and second individual electrodes are provided independently of each other in accordance with the first and second gap amounts, the divided individual vibrations are made to follow the voltage waveform applied to the individual electrodes. The deformation of the plate can be controlled independently.
As a result, the meniscus can be controlled with a high degree of freedom. In addition, more sophisticated and reliable operation has been made possible in ejecting small ink droplets and preventing an increase in viscosity.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing one embodiment of an ink jet recording head of the present invention.

FIG. 2 is an exploded perspective view showing one embodiment of the ink jet recording head of the present invention.

FIG. 3 is a cross-sectional view of the embodiment of FIG. 2 cut along the longitudinal direction of the pressure chamber.

FIG. 4 is a cross-sectional view of the embodiment of FIG. 2 when cut along the direction in which the pressure chambers are arranged.

FIG. 5 is a plan view showing one embodiment of a pattern of a counter electrode in the embodiment of FIG. 2;

FIG. 6 is an explanatory view of an embodiment of the deformation operation of the diaphragm of the ink jet recording head of the present invention.

FIG. 7 is an example of a voltage waveform applied to the ink jet recording head of the present invention.

FIG. 8 is another embodiment of a voltage waveform applied to the ink jet recording head of the present invention.

9 is an explanatory diagram of a deformation operation of the diaphragm based on the voltage waveform of FIG.

FIG. 10 is another example of the voltage waveform applied to the ink jet recording head of the present invention.

11 is an explanatory diagram of a deformation operation of the diaphragm based on the voltage waveform of FIG.

FIG. 12 is another embodiment of the voltage waveform applied to the ink jet recording head of the present invention.

13 is an explanatory diagram of a deformation operation of the diaphragm based on the voltage waveform of FIG.

FIG. 14 shows another embodiment of the voltage waveform applied to the ink jet recording head and the diaphragm deformation operation of the present invention.

FIG. 15 is a view showing another embodiment of the ink jet recording head of the present invention.

16 is a cross-sectional view of the embodiment of FIG. 15 when cut along the longitudinal direction of the pressure chamber.

FIG. 17 is a view showing another embodiment of the ink jet recording head of the present invention.

18 is a plan view of the individual electrode of the embodiment of FIG.

FIG. 19 is a view showing another embodiment of the ink jet recording head of the present invention.

FIG. 20 is a sectional view of the embodiment of FIG. 19;

FIG. 21 is a sectional view showing another embodiment of the ink jet recording head of the present invention.

FIG. 22 is an exploded perspective view showing another embodiment of the ink jet recording head of the present invention.

FIG. 23 is a sectional view showing another embodiment of the ink jet recording head of the present invention.

[Explanation of symbols]

 2 Nozzle plate 3 Flow path forming substrate 4 Counter substrate 5 Nozzle hole 6 Flexible cable 7 Case 9 Ink chamber 10 Pressure chamber 11 Vibration plate 12 First individual electrode 13 Second individual electrode 16 Convex portion formed on opposing substrate 17 Vibration Projection formed on plate 19 Insulating film 23 Voltage waveform 24 Voltage waveform applied to first electrode 25 Voltage waveform applied to second electrode 52 Individual electrode on diaphragm 53 Individual electrode on diaphragm

Claims (13)

[Claims] 1. A plurality of nozzle holes, a pressure chamber communicating with each of the nozzle holes, a vibration plate provided on a wall surface of the pressure chamber, and a counter electrode facing the vibration plate at a predetermined distance. An inkjet head that applies a voltage between the diaphragm and the counter electrode to deform the diaphragm and eject ink droplets from the nozzle holes, wherein at least a first gap is provided with respect to the diaphragm. At least a first and a second opposing surface that the diaphragm can contact when the diaphragm is deformed, and the first and the second surfaces are opposed to each other with a second gap amount larger than the first gap amount. An ink jet recording head comprising: first and second individual electrodes independent of each other provided corresponding to a second gap amount. 2. The ink jet recording head according to claim 1, wherein said first and second individual electrodes are formed on said counter electrode. 3. The ink jet recording head according to claim 1, wherein said first and second individual electrodes are opposed to said counter electrode via an insulator, and are electrodes laminated on a surface of said diaphragm. . 4. The ink jet recording head according to claim 1, wherein the thickness of the diaphragm is stepped so as to form the first gap amount and the second gap amount. 5. The device according to claim 1, further comprising: a first opposing surface protruding from the opposing electrode in the direction of the diaphragm, wherein a first gap is formed between the first opposing surface and the diaphragm. Ink jet recording head. 6. The diaphragm has a protruding surface projecting from the diaphragm in the direction of the counter electrode, and a first gap is formed between the protruding surface and the first facing surface. The ink jet recording head according to the above. 7. The ink jet recording head according to claim 1, wherein a second gap amount is arranged at a central portion in the longitudinal direction of the pressure chamber, and the first gap amount is arranged on both sides thereof. 8. The ink jet recording head according to claim 1, wherein the individual electrodes corresponding to the first gap amount are common to each pressure chamber. 9. A deformation of the diaphragm of the first gap portion for applying a voltage to the first individual electrode, and a diaphragm of the second gap portion for applying a voltage to the second individual electrode. Deformation,
9. The ink jet recording head according to claim 1, wherein the deformation of the diaphragm in the first and second gap portions for applying a voltage to the first and second individual electrodes can be operated independently in timing. . 10. A state in which a voltage is applied to said first individual electrode to deform said diaphragm of said first gap portion in advance,
A voltage is applied to and released from the second individual electrode,
9. The ink jet recording head according to claim 1, wherein the diaphragm at the gap portion is deformed to discharge ink droplets. 11. In a state in which no voltage is applied to the second individual electrode, by applying and releasing a voltage to the first individual electrode, the diaphragm in the first gap amount portion is deformed to form an ink. 9. The ink jet recording head according to claim 1, wherein the meniscus of the nozzle opening is swung so as not to eject a droplet. 12. A state in which a voltage is applied to the first individual electrode to deform the diaphragm of the first gap portion in advance,
A voltage is applied to the second individual electrode to deform the diaphragm of the second gap, and then the voltage of the first and second gaps is released by releasing the voltage of the first and second individual electrodes. The deformation of the diaphragm is released and ink droplets are ejected, and then a voltage is applied only to the first individual electrode to deform the diaphragm of the first gap portion. 9. The ink jet recording head according to claim 1, which performs ejection. 13. The first gap amount is the second gap amount from the second gap amount.
2. The ink jet recording head according to claim 1, wherein the value is larger than a value obtained by subtracting the gap amount of 1.