JP3695509B2 - Inkjet recording head and inkjet recording apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording head and an ink jet recording apparatus that include a pressure generating chamber that communicates with a nozzle opening that discharges ink droplets, and a pressure generating means that generates ink discharge pressure in the pressure generating chamber.
[0002]
[Prior art]
An ink jet recording head that generates pressure in a pressure generating chamber by a piezoelectric element or a heat generating element and discharges ink droplets from the nozzle opening by the pressure is a resistance that generates Joule heat by a driving signal in the pressure generating chamber as pressure generating means. Two types, a bubble jet type provided with a wire and a piezoelectric vibration type in which a part of the pressure generating chamber is constituted by a vibration plate, and the vibration plate is deformed by a piezoelectric element to eject ink droplets from a nozzle opening. It is divided roughly into. In addition, there are two types of piezoelectric vibration-type ink jet recording heads, one that uses a longitudinal vibration mode piezoelectric actuator that expands and contracts in the axial direction of the piezoelectric element and another that uses a flexural vibration mode piezoelectric actuator. Has been.
[0003]
The former can change the volume of the pressure generation chamber by bringing the end face of the piezoelectric element into contact with the vibration plate, and it is possible to manufacture a head suitable for high-density printing, while the piezoelectric element is arranged in an array of nozzle openings. There is a problem that the manufacturing process is complicated because a difficult process of matching the pitch into a comb-like shape and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are necessary.
[0004]
On the other hand, the latter can flexibly vibrate, although a piezoelectric element can be built on the diaphragm by a relatively simple process of sticking a green sheet of piezoelectric material according to the shape of the pressure generation chamber and firing it. There is a problem that a certain amount of area is required for the use of, and high-density arrangement is difficult.
[0005]
On the other hand, in order to eliminate the inconvenience of the latter recording head, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of the diaphragm as seen in Japanese Patent Laid-Open No. 5-286131. A material in which a piezoelectric layer is formed so that a material layer is cut into a shape corresponding to a pressure generation chamber by a lithography method and independent for each pressure generation chamber is proposed.
[0006]
This eliminates the need to affix the piezoelectric element to the diaphragm, so that not only can the piezoelectric element be created by a precise and simple technique called lithography, but also the thickness of the piezoelectric actuator can be reduced. There is an advantage that high-speed driving is possible. In this case, the piezoelectric material layer is provided on the entire surface of the diaphragm, and at least only the upper electrode is provided for each pressure generating chamber, so that the piezoelectric actuator corresponding to each pressure generating chamber can be driven.
[0007]
In such an ink jet recording head, generally, a reservoir is formed as an ink chamber common to the pressure generating chambers, and ink is supplied from the reservoir to the pressure generating chambers. In addition, in order to keep the internal pressure of the reservoir below a certain value, the reservoir is provided with a compliance portion that absorbs a change in pressure when the piezoelectric element is driven by deformation.
[0008]
In addition, such a compliance portion is, for example, a method of forming a part of the reservoir wall with a thin film, or a method of providing an absorption member made of a porous member or the like in the reservoir and causing the absorption member to absorb a pressure change. Is used.
[0009]
[Problems to be solved by the invention]
However, the compliance section as described above has no effect unless the volume is large, and in this case, there is a problem that bubbles are likely to be retained in the reservoir. Therefore, a high-density ink jet recording head that ejects minute ink droplets. There is a problem that cannot be applied.
[0010]
Furthermore, there is a method in which a drive element is provided on one wall constituting the reservoir and the internal pressure is forcibly controlled by driving this drive element. However, it is difficult to adjust the phase accurately, and the drive is driven. There is a problem that it is very difficult to drive appropriately according to the amount of segments.
[0011]
In view of such circumstances, it is an object of the present invention to provide a small and high-density ink jet recording head that effectively absorbs pressure changes in a reservoir and has no crosstalk.
[0018]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the flexible film includes a plurality of segments, wherein at least one of the pair of counter electrodes is divided into a plurality of segments. In the ink jet recording head, the driving element is provided.
[0019]
In the fourth aspect, since the drive elements are formed at a plurality of locations, the pressure change in the reservoir can be absorbed more effectively.
[0020]
[Means for Solving the Problems]
According to a first aspect of the present invention for solving the above-described problem, a pressure generating chamber communicating with a nozzle opening, a reservoir communicating with the pressure generating chamber, and a pressure for generating a pressure for ejecting ink in the pressure generating chamber. In the ink jet recording head comprising the generating means, a flexible film having flexibility is provided on at least one side of the reservoir, and the flexible film is provided on the piezoelectric material layer and on both sides thereof. A driving element including a pair of counter electrodes, wherein the flexible film is divided into a plurality of segments along a traveling direction of a bending wave in which at least one of the pair of counter electrodes propagates to the flexible film. The ink-jet recording head is divided and substantially includes a plurality of driving elements.
[0021]
In the first aspect, the pressure change in the reservoir is absorbed by the deformation of the flexible film and is more effectively absorbed by driving the drive element. And since the drive elements are formed at a plurality of locations along the traveling direction of the bending wave propagating to the flexible film, it is driven in response to the bending wave displacement and effectively absorbs the pressure change of the reservoir. Is done.
[0024]
According to a second aspect of the present invention, in the first aspect, a pitch of the divided counter electrode in a propagation direction of a bending wave propagated to the flexible film is equal to a main bending wavelength of the flexible film. In the ink jet recording head, it is 1/2 or less.
[0025]
In the second aspect, the drive element is more reliably driven in response to the bending wave displacement, and the pressure change is effectively absorbed.
[0026]
According to a third aspect of the present invention, there is provided the ink jet recording head according to the first or second aspect, wherein the piezoelectric material layer constituting the driving element is made of a polymer piezoelectric material.
[0027]
In the third aspect, a flexible drive element can be formed relatively easily.
[0028]
According to a fourth aspect of the present invention, there is provided the ink jet recording head according to the third aspect, wherein the polymer piezoelectric material is polyvinylidene fluoride.
[0029]
In the fourth aspect, by forming the piezoelectric material layer with a specific material, a flexible and thin driving element can be formed relatively easily.
[0030]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the piezoelectric layer constituting the driving element is formed by a sol-gel method, a CVD method, or a sputtering method. An ink jet recording head characterized by the above.
[0031]
In the fifth aspect, a thin piezoelectric material layer can be formed relatively easily.
[0032]
According to a sixth aspect of the present invention, in any one of the first to fourth aspects, the pressure generating means is a piezoelectric element disposed on a vibration plate provided on one surface of the pressure generating chamber. An ink jet recording head characterized by the above.
[0033]
In the sixth aspect, pressure is applied to the pressure generating chamber by ejecting ink droplets by displacing the diaphragm by driving each piezoelectric element.
[0034]
According to a seventh aspect of the present invention, in the sixth aspect, the flow path forming substrate in which the pressure generating chamber is formed is formed of ceramics, and each layer of the piezoelectric element is formed by pasting or printing a green sheet. An ink jet recording head characterized by the above.
[0035]
In the seventh aspect, the head can be easily manufactured by laminating and firing the green sheets.
[0036]
According to an eighth aspect of the present invention, in the sixth aspect, the flow path forming substrate on which the pressure generating chamber is formed is a silicon single crystal substrate, the pressure generating chamber is formed by anisotropic etching, and the piezoelectric The ink jet recording head is characterized in that each layer of the element is formed by a thin film and a lithography method.
[0037]
In the eighth aspect, a large number of ink jet recording heads having high-density nozzle openings can be manufactured relatively easily.
[0038]
A ninth aspect of the present invention is the ink jet recording head according to any one of the first to fifth aspects, wherein the pressure generating means is a heat generating element provided in the pressure generating chamber.
[0039]
In the ninth aspect, by heating the heating elements, Ru ink droplets pressure is applied is discharged to the pressure generating chamber.
A tenth aspect of the present invention is an ink jet recording apparatus comprising the ink jet recording head according to any one of the first to ninth aspects.
In the tenth aspect, an ink jet recording apparatus with improved head ink ejection characteristics can be realized.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments.
[0041]
(Embodiment 1)
FIG. 1 is an exploded view showing an ink jet recording head according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view of FIG.
[0042]
As shown in the drawing, the flow path forming substrate 10 is composed of a silicon single crystal substrate having a plane orientation (110) in this embodiment. As the flow path forming substrate 10, one having a thickness of about 150 to 300 μm is usually used, preferably about 180 to 280 μm, more preferably about 220 μm. This is because the arrangement density can be increased while maintaining the rigidity of the partition between adjacent pressure generating chambers.
[0043]
One surface of the flow path forming substrate 10 is an opening surface, and the silicon single crystal substrate is anisotropically etched in this opening surface, so that the pressure generation chamber 12 partitioned by a plurality of partition walls is formed in the width direction. It is installed side by side. In addition, a nozzle opening 11 through which ink is ejected is formed at one end in the longitudinal direction of each pressure generating chamber 12, and a reservoir 13 serving as a common ink chamber for each pressure generating chamber 12 is formed at the other end. The pressure generating chambers 12 communicate with one end in the longitudinal direction of each pressure generating chamber 12 via an ink supply path 14.
[0044]
Here, in the anisotropic etching, when the silicon single crystal substrate is immersed in an alkaline solution such as KOH, the first (111) plane perpendicular to the (110) plane is gradually eroded and the first (111) The second (111) plane that forms an angle of about 70 degrees with the (110) plane and the angle of about 35 degrees with the (110) plane appears, and is compared with the etching rate of the (110) plane (111) This is performed by utilizing the property that the etching rate of the surface is about 1/180. By this anisotropic etching, precision processing can be performed based on the parallelogram depth processing formed by two first (111) surfaces and two oblique second (111) surfaces. The pressure generating chambers 12 can be arranged with high density. In the present embodiment, the long side of each pressure generating chamber 12 is formed by the first (111) plane and the short side is formed by the second (111) plane.
[0045]
Each nozzle opening 11 communicating with one end of each pressure generation chamber 12 is formed narrower and shallower than the pressure generation chamber 12. On the other hand, each ink supply path 14 that communicates with the other end of each pressure generation chamber 12 is also formed shallower than the pressure generation chamber 12 to maintain a constant flow path resistance of the ink flowing into the pressure generation chamber 12. Yes.
[0046]
These pressure generation chamber 12, nozzle opening 11 and ink supply path 14 are formed by etching the silicon single crystal substrate halfway in the thickness direction (half etching), and the depth is adjusted by adjusting the etching time, respectively. Has been adjusted.
[0047]
Here, the size of the pressure generation chamber 12 that applies ink droplet discharge pressure to the ink and the size of the nozzle opening 11 that discharges ink droplets are optimized according to the amount of ink droplets to be discharged, the discharge speed, and the discharge frequency. The For example, when recording 360 ink droplets per inch, the nozzle opening 11 needs to be accurately formed with a groove width of several tens of μm.
[0048]
Further, an ink introduction port 15 for supplying ink to the reservoir 13 is formed on the side wall of the reservoir 13 of the flow path forming substrate 10, and ink is supplied to the reservoir 13 through the ink introduction port 15. .
[0049]
An elastic film 50 having a through hole 55 in a region facing the reservoir 13 is joined to the opening surface side of the flow path forming substrate 10. Further, as will be described in detail later, the through-hole 55 of the elastic membrane 50 is sealed by the flexible membrane 100 and serves as a compliance portion for absorbing the pressure change in the reservoir. In the present embodiment, the elastic film 50 is made of, for example, silicon dioxide having a thickness of 1 to 2 μm.
[0050]
In the region corresponding to the pressure generation chamber 12 of the elastic film 50, the lower electrode film 60 having a thickness of, for example, about 0.5 μm, the piezoelectric film 70 having a thickness of, for example, about 1 μm, and the thickness of, for example, The upper electrode film 80 of about 0.1 μm is laminated by a process described later to constitute the piezoelectric element 300. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric film 70, and the upper electrode film 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric film 70 are patterned for each pressure generating chamber 12. In addition, here, a portion that is configured by any one of the patterned electrodes and the piezoelectric film 70 and in which piezoelectric distortion is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion 320. In this embodiment, the lower electrode film 60 is a common electrode of the piezoelectric element 300, and the upper electrode film 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. In either case, a piezoelectric active part is formed for each pressure generating chamber. Further, here, the piezoelectric element 300 and the vibration plate that is displaced by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. In the example described above, the elastic film 50 and the lower electrode film 60 act as a diaphragm, but the lower electrode film may also serve as the elastic film.
[0051]
Further, a flexible film 100 that is elastically deformable in the thickness direction is provided in a region corresponding to the through hole 55 of the elastic film 50, and the through hole 55 is sealed by the flexible film 100. .
[0052]
In the present embodiment, a drive element 310 including a piezoelectric material film 75 and a pair of counter electrodes 65 and 85 provided with the piezoelectric material film 75 interposed therebetween is formed in a region corresponding to the through hole 55 of the elastic film 50. The drive element 310 is the flexible film 100.
[0053]
The compliance of the flexible membrane 100 is preferably 10 times or more of the total compliance of the diaphragms in the region facing each pressure generating chamber 12 communicating with the reservoir 13.
[0054]
The material of the pair of counter electrodes 65 and 85 constituting the driving element 310 to be the flexible film 100 is not particularly limited. For example, in this embodiment, aluminum (Al) having a thickness of 0.1 μm is used. Using. The material of the piezoelectric material film 75 is also not particularly limited. For example, in this embodiment, the piezoelectric material film 75 is formed using a polymer piezoelectric material such as polyvinylidene fluoride having a thickness of 2 to 20 μm.
[0055]
The flexible film 100 including the driving element 310 absorbs the pressure change by elastic deformation when the pressure change occurs in the reservoir 13 due to the driving of the piezoelectric element 300 or the like. In other words, the bending wave generated by the pressure change is propagated to the flexible film 100 so that the pressure change is absorbed. As a result, the internal pressure of the reservoir 13 is always kept below a certain value, and the ink ejection characteristics are maintained well.
[0056]
In the present embodiment, as shown in FIG. 2B, the pair of counter electrodes 65 and 85 of the drive element 310 that is the flexible film 100 are connected via a resistor R1 having a predetermined resistance value. ing.
[0057]
Here, when the piezoelectric material film 75 is deformed by the pressure change in the reservoir 13, electric charges are generated between the pair of counter electrodes 65 and 85 sandwiching the piezoelectric material film 75. In the present embodiment, since the pair of counter electrodes 65 and 85 are connected via the resistor R1, the generated charges are discharged by the resistor R1. As a result, the piezoelectric material film 75 is deformed in a direction to return to the original, so that the bending wave is efficiently attenuated. That is, when the driving element 310 is deformed, the bending wave can be attenuated passively.
[0058]
In such an ink jet recording head of this embodiment, when ink is supplied from the ink introduction port 15 to the reservoir 13, the reservoir is usually caused by, for example, the flow of ink when the piezoelectric element 300 is driven or the ambient heat. A pressure change occurs in 13. However, since the flexible film 100 having the drive element 310 is provided on one surface of the reservoir 13, the drive element 310 is bent and deformed to effectively absorb the pressure change. That is, when the driving element 310 is deformed by a bending wave due to a pressure change in the reservoir 13, a force acts in a direction to return to the original, and the bending wave can be passively attenuated. Therefore, the inside of the reservoir 13 is always maintained at a constant pressure or less, and a small and high density ink jet recording head without crosstalk can be realized.
[0059]
Further, since the inside of the reservoir 13 can always be maintained at a pressure equal to or lower than a certain value, the reservoir 13 can be made small. Therefore, the flow rate of the ink in the reservoir 13 is increased, and bubbles can be prevented from remaining in the reservoir 13.
[0060]
In the present embodiment, a through hole 55 is provided in the elastic film 50 in a region facing the reservoir 13, and the driving element 310 provided on the through hole 55 is the flexible film 100. For example, the through-hole 55 may be sealed with a layer made of another member, and a driving element may be provided thereon to form a flexible film.
[0061]
(Embodiment 2)
3 and 4 are a plan view and a cross-sectional view of a main part of the ink jet recording head according to the second embodiment.
[0062]
In the present embodiment, as shown in FIG. 3, on one side of a pair of counter electrodes constituting the drive element 310 to be the flexible film 100, for example, in this embodiment, the counter electrode formed on the piezoelectric material film 75. This is an example in which the electrode 85 is divided into a plurality of segments, and is the same as in the first embodiment except that the flexible membrane 100 substantially includes a plurality of driving elements 310.
[0063]
That is, in this embodiment, the counter electrode 85 is an individual electrode of each drive element 310 of each drive element 310, while the counter electrode 65 is a common electrode of each drive element 310. As shown in FIG. 4, the pair of counter electrodes 65 and 85 of each driving element 310 are connected to each other via a resistor R1 as in the first embodiment.
[0064]
Here, the pitch of the divided counter electrodes 85 in the propagation direction of the bending wave propagating to the flexible film 100 is preferably ½ or less of the main bending wavelength. As a result, the segment of the counter electrode 85 can be provided at a position that deforms in the same phase, and the deformation in the reverse direction of the flexible film 100 caused by the propagation of the bending wave is attenuated more effectively by each drive element 310. Can be made.
[0065]
The traveling direction of the bending wave propagated to the flexible film 100 due to the pressure change in the reservoir 13 is mainly the direction in which ink flows. In other words, in this embodiment, the ink inlet 15 for supplying ink to the reservoir 13 and the ink supply path 14 for supplying ink from the reservoir 13 to the pressure generating chamber 12 are connected.
[0066]
In the present embodiment, the counter electrode 85 formed on the piezoelectric material film 75 is divided into a plurality of segments. However, the present invention is not limited to this. Of course, the other counter electrode 65 is divided into a plurality of segments. You may make it divide | segment.
[0067]
(Embodiment 3)
FIG. 5 is a plan view of an essential part of the ink jet recording head according to the third embodiment.
[0068]
In the present embodiment, as shown in FIG. 5, the counter electrode 85 constituting a part of the flexible film 100 is divided into a plurality of segments along the propagation direction of the bending wave, and a plurality of driving elements 310 are formed. ing.
[0069]
Further, the counter electrode 85 constituting each drive element 310 is further divided in the vicinity of the end portion thereof, and a detection electrode 86 for detecting a potential generated in the drive element 310 due to ink pressure fluctuation in the reservoir 13. A driving electrode 87 for applying a potential to the piezoelectric material film 75 to drive the driving element 310 is provided. The detection electrode 86 and the drive electrode 87 are connected via an inverting amplifier 110 so that the potential is detected by the detection electrode 86 and inverted and amplified by a predetermined factor and applied to the drive electrode 87. It has become.
[0070]
That is, in this embodiment, when a bending wave is propagated to the flexible film 100 due to a pressure change in the reservoir 13, the potential generated by this deformation is detected by the detection electrode 86. The detected electric potential is amplified to a predetermined electric potential by the inverting amplifier 110 and reversed in phase and applied to the driving electrode 87. Thereby, the drive element 310 is actively driven, and the bending wave due to the pressure change can be effectively attenuated.
[0071]
In such a configuration, for example, as in the above-described embodiment, each driving electrode 86 and the other counter electrode 65 may be connected via a resistor. For example, when the pressure change in the reservoir 13 is large immediately after ink is ejected by driving the piezoelectric element 300, the bending wave is actively attenuated as in this embodiment, and in other cases Similarly to the above-described embodiment, the bending wave may be passively attenuated by the resistance.
[0072]
(Embodiment 4)
FIG. 6 is a cross-sectional view of a main part of the ink jet recording head according to the fourth embodiment.
[0073]
In the present embodiment, the drive element 310 that constitutes the flexible film 100 is an example in which the same layer as each layer that constitutes the piezoelectric element 300 is formed.
[0074]
In the present embodiment, as shown in FIG. 6, one surface of the flow path forming substrate 10 is an opening surface, and unlike the above-described embodiment, the thickness is made of silicon dioxide previously formed on the other surface by thermal oxidation. An elastic film 50 having a thickness of 1 to 2 μm is formed.
[0075]
On the other hand, the pressure generating chamber 12, the reservoir 13, and the ink supply path 14 are formed on the opening surface of the flow path forming substrate 10 by anisotropic etching of the silicon single crystal substrate. A nozzle plate 17 having a nozzle opening 11A communicating with the side opposite to the ink supply path 14 of each pressure generating chamber 12 is provided on the opening surface side of the flow path forming substrate 10 with an adhesive, a heat-welded film, or the like. It is fixed through.
[0076]
And the piezoelectric element 300 is formed in the area | region corresponding to the pressure generation chamber 12 of this elastic film 50 similarly to the above-mentioned embodiment, The area | region facing the reservoir | reserver 13 is the same as each layer which comprises the piezoelectric element 300 A driving element 310 composed of layers is formed. That is, the pair of counter electrodes 65 and 85 that constitute the drive element 310 are made of the same layer as the lower electrode film 60 and the upper electrode film 80 that constitute the piezoelectric element 300, and the piezoelectric material layer 75 is the same as the piezoelectric film 70. It consists of layers. In the present embodiment, the through hole is not formed in the elastic film 50 below the flexible film 100, and the elastic film 50 constitutes a part of the flexible film 100.
[0077]
Even with this configuration, it is needless to say that the same effects as those of the above-described embodiment can be obtained. Further, in the present embodiment, since the drive element 310 can be manufactured in the same process as the piezoelectric element 300, the manufacturing process can be simplified and the cost can be reduced. Further, in this embodiment, the elastic film 50 constitutes a part of the flexible film 100. However, since the elastic film 50 is also flexible, the elastic film 50 includes the elastic film 50. However, the pressure change in the reservoir 13 can be sufficiently absorbed.
[0078]
(Embodiment 5)
FIG. 7 is an exploded perspective view of the ink jet recording head according to the fifth embodiment, and FIG. 8 is a cross-sectional view thereof.
[0079]
As illustrated, the present embodiment is an example in which the reservoir 13 is formed by stacking a plurality of substrates on the flow path forming substrate 10 without forming the reservoir 13 on the flow path forming substrate 10.
[0080]
That is, in the present embodiment, one surface of the flow path forming substrate 10 is an opening surface, and an elastic film 50 made of silicon dioxide previously formed by thermal oxidation is formed on the other surface as in the fourth embodiment. On the other hand, a nozzle opening 11 and a pressure generating chamber 12 are formed on the opening surface of the flow path forming substrate 10 by anisotropically etching the silicon single crystal substrate.
[0081]
In addition, a sealing plate 20 in which an ink supply port corresponding to each pressure generating chamber 12 is provided is provided on the opening surface side of the flow path forming substrate 10 so as to cover the entire surface. The reservoir forming substrate 30 and the ink chamber side plate 40 are joined to the sealing plate 20 to form the reservoir 13.
[0082]
The reservoir forming substrate 30 forms the peripheral wall of the reservoir 13 and is manufactured by punching a stainless steel plate having an appropriate thickness according to the nozzle numerical aperture and the ink droplet ejection frequency. The ink chamber side plate 40 constitutes one wall surface of the reservoir 13 on one surface, and an ink introduction port 41 for receiving ink supply from the outside to the reservoir 13 is formed by punching on the other surface. Yes. Further, a part of the region facing the reservoir 13 is removed by etching to form a through hole 42.
[0083]
The through-hole 42 is sealed with a flexible film 100 constituted by a driving element 310 including a piezoelectric material film 75 and a pair of counter electrodes 65 and 85. Similarly to the above-described embodiment, the through-hole 42 of the reservoir 13 is sealed. It is a compliance department.
[0084]
In such a configuration, the pressure generation chamber 12 and the reservoir 13 are communicated with each other through the ink supply communication port 21 formed at a position corresponding to one end of each pressure generation chamber 12 of the sealing plate 20. Ink is supplied from the reservoir 13 through the ink supply communication port 21 and is distributed to the pressure generating chambers 12.
[0085]
Of course, also in the configuration of this embodiment, the pressure change in the reservoir 13 can be effectively absorbed as in the above-described embodiment, and the inside of the reservoir 13 is always maintained at a constant pressure or less. A compact and high-density ink jet recording head without talk can be realized.
[0086]
(Other embodiments)
While the embodiments of the present invention have been described above, the basic configuration of the ink jet recording head is not limited to that described above.
[0087]
For example, in each of the above-described embodiments, the thin film type ink jet recording head manufactured by applying the film forming and lithography processes is taken as an example. However, the present invention is not limited to this example. The present invention can be applied to a thick film type ink jet recording head formed by such a method.
[0088]
In the above-described embodiment, an ink jet recording head having a flexural displacement type piezoelectric element has been described. For example, a longitudinal vibration mode having a structure in which piezoelectric materials and electrode forming materials are alternately sandwiched and stacked. The present invention can be applied to an ink jet recording head having a piezoelectric element.
[0089]
Further, the present invention is not limited to the above-described piezoelectric vibration type ink jet recording head, and can of course be applied to ink jet recording heads having various structures such as a bubble jet ink jet recording head.
[0090]
In addition, the ink jet recording heads of these embodiments constitute a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and are mounted on the ink jet recording apparatus. FIG. 9 is a schematic view showing an example of the ink jet recording apparatus.
[0091]
As shown in FIG. 9, in the recording head units 1A and 1B having the ink jet recording head, cartridges 2A and 2B constituting ink supply means are detachably provided, and a carriage 3 on which the recording head units 1A and 1B are mounted. Is provided on a carriage shaft 5 attached to the apparatus body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.
[0092]
The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S which is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.
[0093]
【The invention's effect】
As described above, in the present invention, since the flexible film having the driving element is provided on one surface of the reservoir, when the bending wave generated by the pressure change in the reservoir is propagated to the flexible film, The drive element can be driven passively or actively to effectively attenuate the bending wave. Thereby, the pressure in the reservoir can always be kept below a certain value.
[0094]
Further, since the inside of the reservoir can always be maintained at a pressure below a certain value, the reservoir can be made small. As a result, the flow rate of the ink in the reservoir increases, and it is possible to prevent bubbles from remaining in the reservoir.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an ink jet recording head according to a first embodiment of the invention.
FIG. 2 is a cross-sectional view of the ink jet recording head according to Embodiment 1 of the invention.
FIG. 3 is a plan view of an ink jet recording head according to a second embodiment of the invention.
FIG. 4 is a cross-sectional view of an ink jet recording head according to a second embodiment of the invention.
FIG. 5 is a plan view of an ink jet recording head according to a third embodiment of the invention.
FIG. 6 is a plan view of an ink jet recording head according to a fourth embodiment of the invention.
FIG. 7 is an exploded perspective view of an ink jet recording head according to a fifth embodiment of the invention.
FIG. 8 is a cross-sectional view of an ink jet recording head according to a fifth embodiment of the invention.
FIG. 9 is a schematic view of an ink jet recording apparatus according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate 11 Nozzle opening 12 Pressure generation chamber 13 Reservoir 14 Ink supply path 60 Lower electrode film 65 Counter electrode 70 Piezoelectric film 75 Piezoelectric material film 80 Upper electrode film 85 Counter electrode 100 Flexible film 300 Piezoelectric element 310 Drive element

Claims (10)

In an ink jet recording head comprising a pressure generating chamber communicating with a nozzle opening, a reservoir communicating with the pressure generating chamber, and pressure generating means for generating a pressure for ejecting ink in the pressure generating chamber.
A flexible film having flexibility is provided on at least one side of the reservoir, and the flexible film includes a driving element including a piezoelectric material layer and a pair of counter electrodes provided on both sides thereof, The flexible membrane is divided into a plurality of segments along the traveling direction of the bending wave propagating to the flexible membrane, and at least one of the pair of counter electrodes substantially includes a plurality of driving elements. An ink jet recording head comprising: In claim 1, the pitch of the divided counter electrode in the propagation direction of the bending wave is propagated to the flexible membrane, and wherein the flexible membrane is 1/2 or less of the main bending wavelengths Inkjet recording head. According to claim 1 or 2, ink jet recording head wherein piezoelectric material layer constituting the driving element, characterized in that it consists of a polymeric piezoelectric material. 4. The ink jet recording head according to claim 3 , wherein the polymeric piezoelectric material is polyvinylidene fluoride. In any one of claims 1-4, wherein the piezoelectric layer constituting the driving element, the sol - an ink jet recording head, wherein the gel method, and is formed by a CVD method or a sputtering method. In any one of claims 1-5, wherein the pressure generating means, an ink jet recording head, which is a piezoelectric element disposed on the vibration plate provided on one surface of the pressure generating chamber. 7. The ink jet recording head according to claim 6 , wherein the flow path forming substrate on which the pressure generating chamber is formed is formed of ceramics, and each layer of the piezoelectric element is formed by pasting or printing a green sheet. Formed according to claim 6, wherein become channel forming substrate which pressure generating chambers is formed of a silicon single crystal substrate, the pressure generating chamber is formed by anisotropic etching, each layer of the piezoelectric element by a thin film and lithography An ink jet recording head characterized by being made.   6. The ink jet recording head according to claim 1, wherein the pressure generating means is a heat generating element provided in the pressure generating chamber. An ink jet recording apparatus characterized by comprising any of the ink jet recording head according to claim 1-9.

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