JP4117504B2 - Inkjet recording head and inkjet recording apparatus - Google Patents

Description

  The present invention relates to an ink jet recording head and an ink jet recording head in which a piezoelectric element is formed through a vibration plate in a part of a pressure generating chamber communicating with a nozzle opening for ejecting ink droplets, and ink droplets are ejected by displacement of the piezoelectric element. The present invention relates to a recording apparatus.

  A part of the pressure generation chamber communicating with the nozzle opening for discharging ink droplets is constituted by a vibration plate, and the vibration plate is deformed by a piezoelectric element to pressurize the ink in the pressure generation chamber to discharge ink droplets from the nozzle opening. Two types of ink jet recording heads have been put into practical use: those using a piezoelectric actuator in a longitudinal vibration mode in which a piezoelectric element extends and contracts in the axial direction, and those using a piezoelectric actuator in a flexural vibration mode.

  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.

  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.

  On the other hand, in order to eliminate the disadvantages of the latter recording head, a uniform piezoelectric material layer is formed over the entire surface of the diaphragm by a film forming technique, and this piezoelectric material layer is shaped to correspond to the pressure generating chamber by lithography. There has been proposed one in which a piezoelectric element is formed so as to be separated for each pressure generating chamber (see Patent Document 1).

  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 element can be reduced. There is an advantage that high-speed driving is possible.

Japanese Patent Laid-Open No. 5-286131

  However, a piezoelectric element manufactured by such a thin film technique and a lithography method has a problem that dielectric breakdown occurs when driving is repeated by applying a voltage to the piezoelectric element. This dielectric breakdown is likely to occur at the boundary portion between the piezoelectric layer and the upper electrode film or the lower electrode film, particularly in the region facing the vicinity of the end of the pressure generating chamber.

  In addition, the influence of humidity is considered as the cause of this dielectric breakdown, and as a countermeasure against this, a structure in which the entire piezoelectric element is covered with a protective film has been proposed. Although this structure can prevent dielectric breakdown, vibration due to driving of the piezoelectric element is proposed. There is a problem that the amount of displacement of the plate decreases.

  In view of such circumstances, it is an object of the present invention to provide an ink jet recording head and an ink jet recording apparatus that prevent dielectric breakdown of a piezoelectric element without reducing the displacement of a diaphragm.

According to a first aspect of the present invention for solving the above-described problems, a pressure generating chamber communicating with a nozzle opening and an area corresponding to the pressure generating chamber are arranged in the order of a lower electrode, a piezoelectric layer and an upper electrode from the pressure generating chamber side. An ink jet recording head comprising a piezoelectric element laminated with a protective film provided on an outer peripheral surface of the piezoelectric element, and the protective film is provided inside the peripheral area of the upper surface of the upper electrode. Having a thin film part with a thinner film thickness than
The protective film extends to the diaphragm on both sides in the width direction of the piezoelectric element in a region facing the pressure generating chamber, and the film thickness of this region is larger than the film thickness of the thin film portion. In the ink jet recording head.
In the first aspect, since the piezoelectric element is covered with the protective film, the dielectric breakdown of the piezoelectric layer is prevented, and the protective film in the region facing the main part of the upper surface of the piezoelectric element is more than in the other regions. Since the thin film portion is a thin film, deformation of the diaphragm due to driving of the piezoelectric element is not hindered. Further, since the rigidity of the diaphragm on the outer side in the width direction of the piezoelectric element, that is, the arm portion of the so-called diaphragm is increased, destruction of the diaphragm due to driving of the piezoelectric element is prevented.

The second aspect of the present invention is characterized in that the piezoelectric element is patterned so that its width gradually decreases toward the upper electrode, and the outer peripheral surface of the piezoelectric element is an inclined surface. In the ink jet recording head of the first aspect.
In the second aspect, since the outer peripheral surface of the piezoelectric element is an inclined surface, a protective film can be formed on the outer peripheral surface of the piezoelectric element relatively easily.

According to a third aspect of the present invention, there is provided the ink jet recording head according to the second aspect, wherein the protective film is formed by a sputtering method.
In the third aspect, the protective film can be formed relatively easily on the outer peripheral surface of the piezoelectric element.

A fourth 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 third aspects.
In the fourth aspect, an ink jet recording apparatus with improved head reliability can be realized.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing an ink jet recording head according to Embodiment 1 of the present invention, and FIG. 2 is a plan view and a cross-sectional structure in the longitudinal direction of one pressure generating chamber.

  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.

  One surface of the flow path forming substrate 10 is an opening surface, and an elastic film 50 having a thickness of 0.1 to 2 μm made of silicon dioxide previously formed by thermal oxidation is formed on the other surface.

  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.

  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. The pressure generation chamber 12 is formed by etching until it substantially passes through the flow path forming substrate 10 and reaches the elastic film 50. Note that the elastic film 50 is extremely small in the amount of being attacked by the alkaline solution for etching the silicon single crystal substrate.

  On the other hand, each nozzle opening 11 communicating with one end of each pressure generating chamber 12 is formed narrower and shallower than the pressure generating chamber 12. That is, the nozzle opening 11 is formed by etching (half etching) the silicon single crystal substrate halfway in the thickness direction. Half etching is performed by adjusting the etching time.

  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.

  Further, each pressure generating chamber 12 and a common ink chamber 31 described later communicate with each other through an ink supply communication port 21 formed at a position corresponding to one end portion of each pressure generating chamber 12 of a sealing plate 20 described later. The ink is supplied from the common ink chamber 31 through the ink supply communication port 21 and is distributed to the pressure generating chambers 12.

The sealing plate 20 is provided with an ink supply communication port 21 corresponding to each of the pressure generation chambers 12 described above, has a thickness of, for example, 0.1 to 1 mm, a linear expansion coefficient of 300 ° C. or less, and, for example, 2 5 to 4.5 [× 10 ⁻⁶ / ° C.]. As shown in FIGS. 3A and 3B, the ink supply communication port 21 may be a single slit hole 21A that crosses the vicinity of the ink supply side end of each pressure generating chamber 12, or a plurality of slits. It may be a hole 21B. The sealing plate 20 entirely covers one surface of the flow path forming substrate 10 on one side, and also serves as a reinforcing plate that protects the silicon single crystal substrate from impact and external force. Further, the sealing plate 20 constitutes one wall surface of the common ink chamber 31 on the other surface.

  The common ink chamber forming substrate 30 forms the peripheral wall of the common ink chamber 31, and is produced by punching a stainless plate having an appropriate thickness according to the nozzle numerical aperture and the ink droplet ejection frequency. In the present embodiment, the common ink chamber forming substrate 30 has a thickness of 0.2 mm.

  The ink chamber side plate 40 is made of a stainless steel substrate, and constitutes one wall surface of the common ink chamber 31 on one surface. Further, the ink chamber side plate 40 is formed with a thin wall 41 by forming a recess 40a by half-etching on a part of the other surface, and an ink introduction port 42 for receiving ink supply from the outside is punched and formed. ing. The thin wall 41 is for absorbing the pressure generated when ink droplets are discharged toward the opposite side of the nozzle opening 11, and is unnecessary for the other pressure generation chamber 12 via the common ink chamber 31. Prevent the application of positive or negative pressure. In the present embodiment, the ink chamber side plate 40 is set to 0.2 mm and a part thereof is a thin wall having a thickness of 0.02 mm in consideration of rigidity required when the ink introduction port 42 is connected to an external ink supply unit. Although the wall 41 is used, the thickness of the ink chamber side plate 40 may be 0.02 mm from the beginning in order to omit the formation of the thin wall 41 by half etching.

  On the other hand, on the elastic film 50 opposite to the opening surface of the flow path forming substrate 10, the lower electrode film 60 with a thickness of, for example, about 0.2 to 0.5 μm and a thickness of, for example, about 1 μm. The piezoelectric layer 70 and the upper electrode film 80 having a thickness of, for example, about 0.02 μm are 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 layer 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 layer 70 are patterned for each pressure generating chamber 12. In this case, a portion that is configured by any one of the patterned electrodes and the piezoelectric layer 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. Here, the piezoelectric element 300 and the elastic film that is displaced by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. In the above-described example, the elastic film 50 and the lower electrode film 60 function as a diaphragm, but the lower electrode film may also serve as the elastic film.

  In addition, as will be described in detail later, in the present embodiment, the protective film 100 made of an insulator is provided on the outer peripheral surface of the piezoelectric element 300 to prevent dielectric breakdown of the piezoelectric layer 70.

  Here, a process of forming the piezoelectric element 300 and the like on the flow path forming substrate 10 made of a silicon single crystal substrate will be described with reference to FIGS. 4 is a cross-sectional view of the pressure generating chamber 12 in the longitudinal direction, and FIG. 5 is a cross-sectional view of the pressure generating chamber 12 in the width direction.

  As shown in FIG. 4A, first, a silicon single crystal substrate wafer to be the flow path forming substrate 10 is thermally oxidized in a diffusion furnace at about 1100 ° C. to form an elastic film 50 made of silicon dioxide.

  Next, as shown in FIG. 4B, the lower electrode film 60 is formed by sputtering. As a material of the lower electrode film 60, platinum or the like is suitable. This is because a piezoelectric layer 70 described later formed by sputtering or sol-gel method needs to be crystallized by firing at a temperature of about 600 to 1000 ° C. in an air atmosphere or an oxygen atmosphere after the film formation. Because. That is, the material of the lower electrode film 60 must be able to maintain conductivity at such a high temperature and in an oxidizing atmosphere, particularly when lead zirconate titanate (PZT) is used as the piezoelectric layer 70. It is desirable that the change in conductivity due to diffusion of lead oxide is small, and platinum is preferable for these reasons.

  Next, as shown in FIG. 4C, the lower electrode film 60 is patterned into a predetermined shape. That is, the lower electrode film 60 is patterned in a region facing the vicinity of one end portion in the longitudinal direction of the pressure generating chamber 12 and provided for each pressure generating chamber 12 from the vicinity of one end portion in the longitudinal direction to the region facing the peripheral wall. Then, the lower electrode film 61 for wiring that forms a part of the wiring that connects the upper electrode film 80 of the piezoelectric active part 320 and the external wiring is formed.

  Next, as shown in FIG. 4D, the piezoelectric layer 70 is formed. In the present embodiment, a so-called sol-gel method is used in which a so-called sol in which a metal organic material is dissolved and dispersed in a solvent is applied and dried to be gelled, and further fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. Formed. As a material for the piezoelectric layer 70, a lead zirconate titanate (PZT) -based material is suitable for use in an ink jet recording head. In addition, the film-forming method of this piezoelectric material layer 70 is not specifically limited, For example, you may form by sputtering method.

  Furthermore, after forming a lead zirconate titanate precursor film by a sol-gel method or a sputtering method, a method of crystal growth at a low temperature by a high-pressure treatment method in an alkaline aqueous solution may be used.

  Next, as shown in FIG. 4E, an upper electrode film 80 is formed. The upper electrode film 80 only needs to be a highly conductive material, and many metals such as aluminum, gold, nickel, and platinum, conductive oxides, and the like can be used. In this embodiment, the platinum film is formed by sputtering.

  Next, as shown in FIG. 5A, the piezoelectric layer 70 and the upper electrode film 80 are collectively etched to pattern the piezoelectric active portion 320 in a region facing each pressure generating chamber 12. At this time, in the present embodiment, patterning is performed so that the width of the piezoelectric active portion 320 gradually becomes narrower toward the upper electrode film 80 side, and the peripheral surface of the piezoelectric active portion 320 is inclined.

  Next, as shown in FIG. 5B, for example, a conductor such as Cr—Au is formed on the entire surface and then patterned to form an upper electrode film 80 and a lower electrode for wiring in each piezoelectric active portion 320. A lead electrode 90 that connects the film 61 is formed.

Next, as shown in FIG. 5C, a protective film 100 made of an insulator is formed on the surface of the piezoelectric active portion 320. The protective film 100 is preferably formed of an oxide film or a nitride film such as SiO ₂ , SiN or ZrO ₂ . In the present embodiment, the protective film 100 made of SiO ₂ is formed with a thickness of about 1 μm on the entire surface by, eg, sputtering, and then patterned to have a predetermined shape. In this embodiment, the piezoelectric active portion A thin film portion 100a having a smaller thickness than other regions is formed in a region facing the main portion of the upper surface of 320. In addition, the patterning method of this thin film part 100a is not specifically limited, For example, what is necessary is just to form in desired thickness by half etching etc.

  Here, in this embodiment, since the outer peripheral surface of the piezoelectric active part 320 is formed as an inclined surface as described above, the protective film 100 is relatively formed on the outer peripheral surface of the piezoelectric active part 320 by sputtering or the like. It can be easily formed thin.

  Thereafter, as shown in FIG. 5D, the silicon single crystal substrate is anisotropically etched with the alkali solution described above to form the pressure generating chamber 12 and the like.

  Through the series of film formation and anisotropic etching described above, a large number of chips are simultaneously formed on a single wafer, and after the completion of the process, for each channel-forming substrate 10 having a single chip size as shown in FIG. To divide. Further, the divided flow path forming substrate 10 is sequentially bonded and integrated with the sealing plate 20, the common ink chamber forming substrate 30, and the ink chamber side plate 40 to form an ink jet recording head.

  The ink jet recording head configured in this manner takes in ink from an ink inlet 42 connected to an external ink supply means (not shown), fills the interior from the common ink chamber 31 to the nozzle opening 11, and then does not show the ink. Pressure is generated by applying a voltage between the lower electrode film 60 and the upper electrode film 80 in accordance with a recording signal from an external drive circuit to bend and deform the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70. The pressure in the chamber 12 increases and ink droplets are ejected from the nozzle openings 11.

  FIG. 6 is a plan view and a cross-sectional view showing the main part of the ink jet recording head of this embodiment formed as described above.

  As shown in FIG. 6, the lower electrode film 60 constituting the piezoelectric element 300 is continuously provided in a region facing the plurality of pressure generating chambers 12 arranged side by side and in the vicinity of one end in the longitudinal direction of the pressure generating chamber 12. Patterned with In addition, a lower electrode film 61 for wiring that is discontinuous with the lower electrode film 60 is provided outside the end portion of the lower electrode film 60 from the region facing the pressure generation chamber 12 to the peripheral wall.

  On the other hand, in this embodiment, the piezoelectric layer 70 and the upper electrode film 80 are provided in a region facing the pressure generation chamber 12 to form the piezoelectric active portion 320. Further, the piezoelectric active portion 320 is patterned so that the width becomes narrower toward the upper electrode film 80 side as described above, and its side surface is inclined. Further, the upper electrode film 80 is connected to the lower electrode film 61 for wiring in the vicinity of the end portion in the longitudinal direction through the lead electrode 90, and the lower electrode film 61 for wiring is connected to an external wiring, although not shown. This constitutes a part of the wiring of the piezoelectric active part 320.

  Further, a protective film 100 made of an insulator is provided on the surface of the piezoelectric element 300 (piezoelectric active part 320), and the region covering the main part of the upper surface of the piezoelectric active part 320 of the protective film 100 is other than The thin film portion 100a is thinner than the thickness of the region. The film thickness of the thin film portion 100a is not particularly limited, but may be thin enough that the deformation of the diaphragm due to the driving of the piezoelectric active portion 320 is not hindered.

  Thus, in this embodiment, since the protective film 100 is provided on the outer peripheral surface of the piezoelectric active part 320, moisture, hydrogen, alkali metal, alkaline earth metal, etc. pass through the upper electrode film 80 to the piezoelectric layer 70. Since the thin film portion 100a is a region covering the main part of the upper surface of the piezoelectric active portion 320 of the protective film 100, the piezoelectric active portion 320 can be prevented from penetrating and deteriorating the piezoelectric layer 70. Therefore, the deformation of the diaphragm due to the driving of the ink is not hindered, and the ink ejection characteristics can be maintained well.

  Furthermore, by providing the protective film 100 on the outer peripheral surface of the piezoelectric active part 320, it is not necessary to provide a sealing member or the like that seals the piezoelectric element and shields it from the outside air, thereby simplifying the head and reducing the cost. Can be reduced.

(Embodiment 2)
FIG. 7 is a cross-sectional view of a main part of the ink jet recording head according to the second embodiment.

  In the present embodiment, as shown in FIG. 7, the protective film 100 formed on the outer peripheral surface of the piezoelectric active part 320 is formed as a thin film part 100 a having such a thin film thickness that does not hinder driving of the piezoelectric active part 320. It was. Further, the protective film 100 is extended to the diaphragms on both sides in the width direction of the piezoelectric active part 320, and the protective film 100 in the region facing the diaphragm is formed with a thick film part 100b thicker than the thin film part 100a. Except for the above, this embodiment is the same as Embodiment 1.

  In such a configuration, the protective film 100 on the diaphragm in the width direction of the piezoelectric active part 320, that is, the arm part of the so-called diaphragm is the thick film part 100b, so the film thickness of the arm part of the diaphragm is Thickness increases and rigidity increases. Thereby, it is possible to prevent the diaphragm from being destroyed due to deformation caused by driving the piezoelectric active part 320.

  Further, since the protective film 100 on the outer peripheral surface of the piezoelectric active part 320 is the thin film part 100a, the driving of the piezoelectric active part 320 is not hindered as in the above-described embodiment, and the ink ejection characteristics. Can also be held well.

  In the present embodiment, the protective film 100 on the outer peripheral surface of the piezoelectric active part 320 is entirely the thin film part 100a. However, the present invention is not limited to this, and as shown in FIG. 8, at least the upper surface of the piezoelectric active part 320 It is only necessary that the protective film 100 of the main part is the thin film part 100a. Of course, the same effect can be obtained with such a configuration.

(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.

  For example, in the above-described embodiment, the example in which the side surface of the piezoelectric active part 320 is the inclined surface has been described, but it is needless to say that the side surface need not be inclined.

  Further, for example, in the above-described embodiment, the protective film 100 is patterned for each of the piezoelectric active portions 320. However, the present invention is not limited to this, and the protective film 100 is continuously provided on the plurality of piezoelectric active portions 320. Also good.

  Further, for example, in addition to the sealing plate 20 described above, the common ink chamber forming substrate 30 may be made of glass ceramics, and may be made of glass ceramics with the thin wall 41 as a separate member. Is free.

  Furthermore, in the above-described embodiment, the nozzle opening 11 is formed on the end face of the flow path forming substrate 10, but a nozzle opening protruding in a direction perpendicular to the face may be formed.

  FIG. 9 shows an exploded perspective view of the embodiment configured as described above, and FIG. 10 shows a cross section of the flow path. In this embodiment, the nozzle openings 11 are formed in the nozzle substrate 120 opposite to the piezoelectric elements, and the nozzle communication ports 22 that connect the nozzle openings 11 and the pressure generation chambers 12 are the sealing plate 20 and the common ink chamber. Arranged so as to penetrate the formation substrate 30, the thin plate 41A, and the ink chamber side plate 40A.

  The present embodiment is basically the same as the above-described embodiment except that the thin plate 41A and the ink chamber side plate 40A are separate members, and the opening 40b is formed in the ink chamber side plate 40A. Are denoted by the same reference numerals, and redundant description is omitted.

  Of course, the present invention can be similarly applied to an ink jet type recording head in which a common ink chamber is formed in a flow path forming substrate.

  As described above, the present invention can be applied to ink jet recording heads having various structures as long as the gist of the invention is not contradicted.

  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. 11 is a schematic view showing an example of the ink jet recording apparatus.

  As shown in FIG. 11, 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.

  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.

  As described above, according to the present invention, since the outer peripheral surface of the piezoelectric element is completely covered with the protective film made of an insulator, the insulation of the piezoelectric layer of the piezoelectric element due to the external environment such as moisture in the atmosphere. Destruction can be prevented.

  In addition, since the thin film portion having a smaller film thickness than the other regions is provided in the region of the protective film facing the upper surface main portion of the piezoelectric element, deformation of the diaphragm due to driving of the piezoelectric element may be hindered. The ink ejection characteristics can be maintained well.

1 is an exploded perspective view of an ink jet recording head according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an ink jet recording head according to Embodiment 1 of the invention, and is a plan view and a cross-sectional view of FIG. It is a figure which shows the modification of the sealing plate of FIG. It is a figure which shows the thin film manufacturing process of Embodiment 1 of this invention. It is a figure which shows the thin film manufacturing process of Embodiment 1 of this invention. 1A and 1B are a plan view and a cross-sectional view of a main part of an ink jet recording head according to Embodiment 1 of the invention. It is principal part sectional drawing of the inkjet recording head which concerns on Embodiment 2 of this invention. It is principal part sectional drawing which shows the other example of the inkjet recording head which concerns on Embodiment 2 of this invention. FIG. 6 is an exploded perspective view of an ink jet recording head according to another embodiment of the present invention. It is sectional drawing which shows the inkjet recording head which concerns on other embodiment of this invention. 1 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, 12 Pressure generating chamber, 50 Elastic film, 55 Insulating film, 60 Lower electrode film, 70 Piezoelectric layer, 80 Upper electrode film, 90 Lead electrode, 100 Protective film, 300 Piezoelectric element, 320 Piezoelectric active Part

Claims (4)

An ink jet recording head comprising: a pressure generating chamber communicating with a nozzle opening; and a piezoelectric element formed by laminating a lower electrode, a piezoelectric layer, and an upper electrode in this order from the pressure generating chamber side in a region corresponding to the pressure generating chamber In
A protective film provided on the outer peripheral surface of the piezoelectric element, the protective film has a thin film portion having a film thickness thinner than the peripheral region inside the peripheral region of the upper surface of the upper electrode ;
The protective film extends to the diaphragm on both sides in the width direction of the piezoelectric element in a region facing the pressure generating chamber, and the film thickness of this region is larger than the film thickness of the thin film portion. An ink jet recording head.   2. The ink jet type according to claim 1, wherein the piezoelectric element is patterned so that its width gradually becomes narrower toward the upper electrode side, and an outer peripheral surface of the piezoelectric element is an inclined surface. Recording head.   The ink jet recording head according to claim 2, wherein the protective film is formed by a sputtering method.   An ink jet recording apparatus comprising the ink jet recording head according to claim 1.

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