JP2009148985A - Liquid jetting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a change in elastic modulus of the vibration plate by preventing quality deterioration of the vibration plate. <P>SOLUTION: The liquid jetting head 10 includes: a flow-path forming base plate 12 where a liquid flow path with a pressure generation chamber 11 communicating with a nozzle opening 13 for jetting the liquid is formed; the vibration plate 13 disposed facing the pressure generation chamber 11; and a pressure generating means for generating a pressure change in the pressure generating chamber 11 through the vibration plate 15. A protective film 60 is disposed in an area constituting the pressure generation chamber 11 on the surface, located on the pressure generation chamber 11 side, of the vibration plate 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head that ejects liquid from nozzle openings, and more particularly to an ink jet recording head that ejects ink as liquid.

  As a typical example of a liquid ejecting head, for example, an ink jet recording head that ejects ink droplets from nozzle openings using pressure generated by displacement of a piezoelectric element is known. Specifically, a flow path unit having a flow path forming plate provided with a pressure generating chamber communicating with the nozzle opening and a vibration plate provided on one side thereof, and bonded to the flow path unit via an adhesive A nozzle plate having a nozzle opening; a piezoelectric element (piezoelectric vibrator) provided corresponding to each pressure generating chamber and fixed to a support substrate; and a case head (base) having a storage chamber for storing the piezoelectric element; (For example, refer to Patent Document 1).

JP 2000-33713 A (for example, refer to claim 1)

  In the ink jet recording head of the above aspect, since the vibration plate is provided on one surface side of the flow path forming plate in which the pressure generating chamber is provided, the surface of the vibration plate on the flow path forming plate side is directly pressurized. It is in contact with the ink in the generation chamber. Depending on the content of the ink, the diaphragm may change over time, and may deteriorate particularly when the diaphragm is made of a resin film. If the vibration plate changes in quality, the elastic modulus of the vibration plate changes, and as a result, there is a problem that the print characteristics of the ink jet recording head may change.

  On the other hand, when the material of the diaphragm itself is changed to a material having ink resistance, the elastic modulus of the diaphragm itself changes, and there is a problem that the design of the entire ink jet recording head must be changed. .

  In view of the above-described problems of the related art, it is an object of the present invention to provide a liquid ejecting head that can be adapted to an existing liquid ejecting head without causing the diaphragm to change over time.

  The liquid ejecting head of the present invention includes a flow path forming substrate having a liquid flow path having a pressure generating chamber communicating with a nozzle opening for ejecting liquid, a diaphragm provided to face the pressure generating chamber, and a vibration A liquid ejecting head including pressure generating means for generating a pressure change in the pressure generating chamber via a plate, the surface of the diaphragm on the pressure generating chamber side being resistant to the liquid in the pressure generating chamber A protective film is provided. By forming a protective film having resistance to the liquid in the pressure generation chamber on the surface on the pressure generation chamber side, it is possible to prevent the vibration plate from being altered.

  In this case, it is preferable that the protective film is provided on a surface portion of the vibration plate on the pressure generation chamber side facing the liquid flow path of the flow path forming substrate. Since the diaphragm comes into contact with the liquid at the surface portion facing the liquid flow path, and the vibration plate changes in quality, if a protective film is provided on the surface portion facing the liquid flow path, the vibration of the vibration plate and the elasticity resulting therefrom The rate change can be suppressed.

  Here, in the case where the diaphragm includes an elastic film made of a resin film, by providing a protective film that is resistant to the liquid in the pressure generating chamber, the diaphragm is altered by the liquid in the pressure generating chamber. It can prevent more effectively.

  Further, as a liquid ejecting head that may change the quality of the vibration plate due to the liquid in the pressure generating chamber, the pressure generating means is formed by vertically stacking a piezoelectric material and an electrode forming material, and cutting the piezoelectric element into comb teeth. A piezoelectric element unit including a formed piezoelectric element forming member and a fixed substrate to which the piezoelectric element forming member is fixed, and the liquid ejecting head exposes the piezoelectric element in a state where a tip surface of the piezoelectric element is exposed. The case includes a case head in which the fixed substrate is fixed by an adhesive, and the diaphragm is joined to an end surface of the case head at which a tip surface of the piezoelectric element is exposed. Examples include fixing the front end surface of the piezoelectric element. By providing the protective film of the present invention with respect to such a liquid jet head, it is possible to suppress the deterioration of print quality.

  It is preferable that a protective member is provided at the periphery of the opening provided in the diaphragm for communicating the ink flow path provided in the case head and the pressure generation chamber of the flow path forming substrate. By providing a protective member not only on the surface facing the pressure generating chamber but also on the peripheral portion of the opening provided in the diaphragm, it is possible to further suppress the deterioration of the diaphragm.

  In this case, it is preferable that the protective member provided at the peripheral edge portion of the opening is formed by extending an adhesive for bonding the case head and the diaphragm. When it is difficult to provide a protective member at the periphery of the opening, it is possible to easily suppress the deterioration of the diaphragm by extending an adhesive for bonding the case head and the diaphragm. .

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2.
(Embodiment 1)
FIG. 1 is a cross-sectional view of an ink jet recording head that is an example of a liquid ejecting head according to Embodiment 1 of the invention. FIG. 2 is an enlarged sectional view of the ink jet recording head shown in FIG. In FIG. 1 and FIG. 2, the same reference numerals are assigned to the same components. First, an example of an ink jet recording head according to Embodiment 1 of the present invention will be described. However, the present invention can be applied to ink jet recording heads having other configurations.

  As shown in FIG. 1, the ink jet recording head 10 includes a flow path forming substrate 12 having a plurality of pressure generation chambers 11 and a nozzle plate 14 in which a plurality of nozzle openings 13 communicating with the pressure generation chambers 11 are formed. And a flow path unit 16 including a vibration plate 15 provided on the surface of the flow path forming substrate 12 opposite to the nozzle plate 14. Furthermore, a piezoelectric element unit 18 having a piezoelectric element 17 provided in a region corresponding to each pressure generating chamber 11 on the vibration plate 15, and an accommodating portion 19 that is fixed on the vibration plate 15 and accommodates the piezoelectric element unit 18. And a case head 20.

  In the flow path forming substrate 12, a plurality of pressure generating chambers 11 are partitioned by a partition wall and arranged in parallel in the width direction on the surface layer portion on one side. For example, in the present embodiment, a plurality of pressure generating chambers 11 are arranged in parallel on the flow path forming substrate 12. A reservoir 22 to which ink is supplied via an ink flow path 21 communicating with ink supply means (not shown) outside the case head 20 is disposed outside the row of the pressure generating chambers 11. It is provided penetrating in the thickness direction. The reservoir 22 and each pressure generation chamber 11 communicate with each other via an ink supply path 23, and ink is supplied to each pressure generation chamber 11 via an ink flow path 21 and the reservoir 22 from an ink supply unit. . In this embodiment, the ink supply path 23 is formed with a width narrower than that of the pressure generation chamber 11, and plays a role of maintaining a constant flow path resistance of ink flowing from the reservoir 22 into the pressure generation chamber 11. Further, a nozzle communication hole 24 penetrating the flow path forming substrate 12 is formed on the end side of the pressure generating chamber 11 opposite to the reservoir 22. That is, in the present embodiment, the flow generation substrate 12 is provided with the pressure generation chamber 11, the reservoir 22, the ink supply path 23, and the nozzle communication hole 24 as liquid flow paths. In this embodiment, the flow path forming substrate 12 is made of a silicon single crystal substrate, and the pressure generating chamber 11 and the like provided in the flow path forming substrate 12 are formed by etching the flow path forming substrate 12. ing.

  A nozzle plate 14 in which nozzle openings 13 are formed is bonded to one surface side of the flow path forming substrate 12 via an adhesive 50, and each nozzle opening 13 communicates with a nozzle provided on the flow path forming substrate 12. The pressure generating chambers 11 communicate with each other through the holes 24.

  Further, a diaphragm 15 is bonded to the other surface side of the flow path forming substrate 12, that is, the opening surface side of the pressure generating chamber 11, and each pressure generating chamber 11 is sealed by the diaphragm 15.

  The diaphragm 15 is formed of a composite plate of, for example, an elastic film 25 made of an elastic member such as a resin film and a support plate 26 made of, for example, a metal material that supports the elastic film 25 and is elastic. The film 25 side is bonded to the flow path forming substrate 12. For example, in the present embodiment, the elastic film 25 is made of a PPS (polyphenylene sulfide) film having a thickness of about several μm, and the support plate 26 is made of a stainless steel plate (SUS) having a thickness of about several tens of μm. In addition, an island portion 27 with which the tip end portion of the piezoelectric element 17 abuts is provided in a region of the vibration plate 15 facing each pressure generation chamber 11. The front end surface of the piezoelectric element 17 is bonded to the island portion 27 with an adhesive 28. Further, in the present embodiment, a compliance portion 29 that is substantially composed only of the elastic film 25 is provided in the region of the diaphragm 15 that faces the reservoir 22 by removing the support plate 26 by etching. The compliance portion 29 absorbs the pressure change by the deformation of the elastic film 25 of the compliance portion 29 when the pressure change in the reservoir 22 occurs, and always keeps the pressure in the reservoir 22 constant. Fulfill. Further, as shown in FIG. 2, an opening 30 is provided in the vibration plate 15 so that the ink flow path 21 and the reservoir 22 communicate with each other.

  Such a diaphragm 15 is bonded to the flow path forming substrate 12 via an adhesive 51.

  Here, in the present embodiment, an ink-resistant protective film 60 is provided on the entire surface of the vibration plate 15 on the flow path forming substrate 12 side (the opening surface side of the pressure generation chamber 11). Since the vibration plate 15 is joined to the opening surface side of the pressure generation chamber 11 and each pressure generation chamber 11 is sealed by the vibration plate, the vibration plate 15 is directly inside the pressure generation chamber 11. Contact ink. In this case, the vibration plate 15 may be deteriorated over time due to components contained in the ink in the pressure generation chamber 11, and the elastic modulus of the vibration plate 15 may be reduced. Therefore, by providing the ink-resistant protective film 60 on the flow path forming substrate 12 side (the opening surface side of the pressure generating chamber 11) of the vibration plate 15 as described above, the vibration plate 15 is deteriorated by ink and accompanying this. It is possible to suppress the deterioration of the printing quality of the ink jet recording head 10 configured to discharge the ink by the vibration of the vibration plate 15 while suppressing the decrease in the elastic modulus of the vibration plate 15. In addition, since the diaphragm 15, particularly the elastic film 25 itself that is easily altered by the ink constituting the diaphragm 15, is not made of a material that is difficult to alter, the protective film 60 is provided on the existing diaphragm 15, so that the ink There is no need to design a new diaphragm itself that affects the printing characteristics of the printer.

  In view of the ease of formation, the protective film 60 is provided over the entire surface of the vibration plate 15 on the flow path forming substrate 12 side as described above, but faces the liquid flow path of the vibration plate 15. If the surface is provided on at least the portion of the ink contact surface 61 facing the pressure generation chamber 11, the reservoir 22, and the ink supply path 23, the lowering of the elastic modulus can be suppressed. Preferably, the protective film 60 is provided on the entire ink contact surface 61 of the vibration plate 15. By being provided on the entire ink contact surface 61 (surface facing the liquid flow path), it is possible to suppress the deterioration of the vibration plate 15 due to the ink and the accompanying decrease in the elastic modulus of the vibration plate 15.

  Further, examples of the ink contact portion of the vibration plate 15 include not only the ink contact surface 61 but also the peripheral portion 62 of the opening 30 of the vibration plate 15 provided for communicating the ink flow path 21 and the reservoir 22. . Although the peripheral edge 62 is separated from the surface facing the pressure generating chamber 11, the influence of the deterioration of the diaphragm 15 from the peripheral edge 62 may be increased after a long time has passed. It is preferable to provide the protective member 63. The protective member 63 may be the same as the protective film 60 described above, but it may be difficult to form a protective film on the peripheral edge 62. Therefore, in the present embodiment, the protective member 63 is formed by overhanging the adhesive 28 provided to bond the case head 20 and the diaphragm 15 to the fixed substrate 26 side. . The protective member 63, which is the adhesive 28, protects the peripheral edge 62 of the opening of the diaphragm 15 and prevents the diaphragm 15 from being altered.

  Further, a protective film 60 may be provided on the piezoelectric element 17 side of the vibration plate 15 or on the piezoelectric element 17 side of the elastic film 25. In this case, the protective film is provided on both sides of the vibration plate 15. In order not to change the elastic modulus, the protective film 60 is formed thinner, for example, or made of a material that does not change the elastic modulus. Of course, the elastic film 25 can be made thin and the protective film 60 can be made thick.

As the protective film 60, any film can be applied as long as it can suppress deterioration of the diaphragm 15 due to ink. Examples of such a film include a metal film, an organic film, and an inorganic film. Examples of the metal used as the metal film include Cr, Mo, Zr, Ni, and Pt. Examples of the organic film include a film made of a rubber material having particularly high solvent resistance, such as a fluorine rubber film and a silicone rubber film. Examples of the inorganic film include a metal oxide film (Al ₂ O ₃ film, SiO ₂ film, etc.) and the like. In addition, since the present invention is intended for not only an ink jet recording head that ejects ink but also a liquid ejecting head that ejects liquid other than ink, the material of the protective film 60 is changed from the above material to the type of liquid. It can be appropriately selected depending on the case. According to the present embodiment, for example, even if the acidity of the ink is high and the elastic film 25 is easily deteriorated, by providing a highly acid-resistant film (for example, a SiO ₂ film) according to the ink, Alteration of the elastic film 25 can be suppressed.

  When a metal film is formed as the protective film 60, it is formed on the ink contact portion of the diaphragm 15, that is, the ink contact surface 61 or the ink contact surface 61 and the peripheral edge portion 62 of the opening 30. This is because if the metal film as the protective film 60 is provided on the piezoelectric element 17 side of the vibration plate 15, the island part 27 is connected to other members, and the insulation of the island part 27 cannot be maintained.

  In this case, the protective film 60 is provided with a thickness that does not change the printing characteristics due to the change in the elastic modulus of the diaphragm 15. Although the allowable thickness of the protective film 60 depends on the material constituting the protective film 60, for example, the thickness is preferably about 100 mm or more if it is the above material.

  The protective film 60 is formed on the surface of the elastic film 25 constituting the vibration plate 15 opposite to the surface to which the support plate 26 is fixed after the elastic film 25 and the support plate 26 are joined via an adhesive layer (not shown). It is formed. As a formation method, a known film formation method such as a PVD method, a CVD method, a spin coating method, a dipping method, or the like can be given, and can be appropriately selected depending on the material of the protective film 60 and the shape of the protective film 60.

  For example, when the protective film 60 is formed on the entire flow path forming substrate 12 side of the diaphragm 15 as shown in FIG. 1, the protective film 60 is provided on the diaphragm 15 by the PVD method, the CVD method, or the spin coating method. Just do it. In the case where the protective film 60 is also formed on the peripheral portion of the opening 30 of the vibration plate 15, the vibration film 15 in which the elastic film 25 and the support plate 26 are bonded via an adhesive layer (not shown) by dipping is used. By immersing in a liquid made of 60 materials, the protective film 60 can be easily formed on the peripheral edge of the opening 30 of the diaphragm 15. In this case, since the diaphragm 15 is formed on both sides, the protective film 60 to be formed may be an insulating film in order to insulate the island portion 27 as described above.

  Here, the piezoelectric element 17 which is a pressure generating means for generating a pressure for ejecting ink droplets into the pressure generating chamber 11 will be described. In the present embodiment, the piezoelectric element 17 is integrally formed in one piezoelectric element unit 18. That is, a piezoelectric element forming member 34 in which the piezoelectric material 31 and the electrode forming materials 32 and 33 are vertically sandwiched and laminated is formed to correspond to each pressure generating chamber 11. Each piezoelectric element 17 is formed by cutting into comb teeth. That is, in the present embodiment, the plurality of piezoelectric elements 17 are integrally formed. An inactive region that does not contribute to the vibration of the piezoelectric element 17 (piezoelectric element forming member 34), that is, the base end side of the piezoelectric element 17 is fixed to the fixed substrate 35. In the present embodiment, the piezoelectric element unit 18 is configured by the piezoelectric element 17 (piezoelectric element forming member 34) and the fixed substrate 35. In the vicinity of the base end portion of the piezoelectric element 17, a circuit board 37 having a wiring 36 for supplying a signal for driving each piezoelectric element 17 is connected to the surface opposite to the fixed board 35.

  Such a piezoelectric element unit 18 is fixed in a state where the distal end portion of the piezoelectric element 17 is in contact with the island portion 27 of the diaphragm 15 as described above. For example, in this embodiment, the case head 20 is fixed on the diaphragm 15 as described above, and the piezoelectric element unit 18 is accommodated in the accommodating portion 19 of the case head 20 and the piezoelectric element 17 is fixed. The fixed substrate 35 thus fixed is fixed to the case head 20 on the side opposite to the piezoelectric element 17. Specifically, a stepped portion 38 is provided in the accommodating portion 19 of the case head 20, and the fixed substrate 35 is bonded to the stepped portion 38 of the case head 20 with an adhesive 39.

  Further, a wiring board 41 provided with a plurality of conductive pads 40 to which the respective wirings 36 of the circuit board 37 are connected is fixed on the case head 20. 41 is substantially blocked. The wiring board 41 is formed with a slit-like opening 42 in a region facing the housing part 19 of the case head 20, and the circuit board 37 is drawn out of the housing part 19 from the opening 42 of the wiring board 41. It is.

  Moreover, the circuit board 37 which comprises the piezoelectric element unit 18 consists of chip-on-film (COF) in which the drive IC (not shown) for driving the piezoelectric element 17 was mounted in this embodiment, for example. Each wiring 36 of the circuit board 37 is connected to the electrode forming materials 32 and 33 constituting the piezoelectric element 17 by, for example, solder, anisotropic conductive material, or the like on the base end side. On the other hand, each wiring 36 is joined to each conductive pad 40 of the wiring board 41 on the tip side. Specifically, each wiring 36 is connected to the wiring board 41 in a state in which the tip of the circuit board 37 drawn out of the housing part 19 from the opening 42 of the wiring board 41 is bent along the surface of the wiring board 41. The conductive pads 40 are joined to each other.

  In such an ink jet recording head 10, when ejecting ink droplets, the volume of each pressure generating chamber 11 is changed by deformation of the piezoelectric element 17 and the vibration plate 15 to eject ink droplets from a predetermined nozzle opening 13. It is designed to be discharged. Specifically, when ink is supplied to the reservoir 22 from an ink cartridge (not shown), the ink is distributed to each pressure generating chamber 11 via the ink supply path 23. Actually, the piezoelectric element 17 is contracted by applying a voltage to the piezoelectric element 17. As a result, the diaphragm 15 is deformed together with the piezoelectric element 17 to expand the volume of the pressure generating chamber 11, and ink is drawn into the pressure generating chamber 11. After the ink is filled up to the nozzle opening 13, the voltage applied to the electrode forming materials 32 and 33 of the piezoelectric element 17 is released according to a recording signal supplied via the wiring board. As a result, the piezoelectric element 17 is expanded to return to the original state, and the diaphragm 15 is also displaced to return to the original state. As a result, the volume of the pressure generation chamber 11 contracts, the pressure in the pressure generation chamber 11 increases, and ink droplets are ejected from the nozzle openings 13.

  The ink jet recording head 10 of the present embodiment constitutes a part of a recording head unit including an ink flow path communicating with an ink cartridge or the like, and is mounted on an ink jet recording apparatus. FIG. 3 is a schematic view showing an example of the ink jet recording apparatus.

  As shown in FIG. 3, the recording head units 1A and 1B having the ink jet recording head 10 are detachably provided with cartridges 2A and 2B constituting ink supply means, and a carriage on which the recording head units 1A and 1B are mounted. 3 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.

  In the first embodiment described above, the longitudinal vibration type piezoelectric element 17 has been described as the pressure generating means for causing a pressure change in the pressure generating chamber 11, but the present invention is not limited to this, and a method of attaching a green sheet or the like. A thick film type piezoelectric element formed by the above can be used. Hereinafter, the second ink jet recording head of the present invention to which a thick film type piezoelectric element is applied will be briefly described. 4 is an exploded perspective view of an ink jet recording head according to Embodiment 2 of the present invention, and FIG. 5 is a cross-sectional view of the ink jet recording head according to Embodiment 2 of the present invention.

  According to FIG. 4, the ink jet recording head 110 of this embodiment includes a plurality of, for example, four actuator units 120, one flow path unit 130 to which the four actuator units 120 are fixed, and the actuator unit 120. It is comprised with the film-form wiring board 150 connected to.

  The actuator unit 120 is an actuator device including the piezoelectric element 140, and includes a flow path forming substrate 122 in which the pressure generation chamber 121 is formed, a vibration plate 123 provided on one surface side of the flow path forming substrate 122, And a pressure generation chamber bottom plate 124 provided on the other surface side of the path forming substrate 122.

The flow path forming substrate 122 is made of, for example, a ceramic plate such as alumina (Al ₂ O ₃ ) or zirconia (ZrO ₂ ) having a thickness of about 150 μm, and in the present embodiment, the plurality of pressure generation chambers 121 have their widths. Two rows arranged in parallel along the direction are formed. A vibration plate 123 made of, for example, a 10 μm-thick zirconia thin plate is fixed to one surface of the flow path forming substrate 122, and one surface of the pressure generating chamber 121 is sealed with the vibration plate 123.

  A protective film 60 is provided on the flow path forming substrate side of the vibration plate 123. Also in the present embodiment, by providing the ink-resistant protective film 60 on the pressure generating chamber 121 side of the diaphragm 123, the deterioration of the diaphragm 123 and the accompanying change in the elastic modulus of the diaphragm can be prevented, and printing can be performed. Quality deterioration can be prevented. In this case, for example, since the diaphragm 123 is made of zirconia, its characteristics are different from those of the elastic film 25 described in the first embodiment. Therefore, a material corresponding to the diaphragm 123 is used as the protective film 60. If selected and provided with a thickness that does not change the elastic modulus of the diaphragm 123, it is possible to suppress the deterioration of the printing characteristics due to the deterioration of the diaphragm 123 over time without changing the design of the existing diaphragm 123. .

  The piezoelectric element 140 is provided in each of the regions facing the pressure generation chambers 121 on the diaphragm 123. For example, in this embodiment, two rows of the pressure generation chambers 121 are provided. There are also two rows. The flow path forming substrate 122, the vibration plate 123, and the pressure generation chamber bottom plate 124, which are each layer of the actuator unit 120, are formed of a clay-like ceramic material, a so-called green sheet, to a predetermined thickness, for example, a pressure generation chamber. After drilling 121 and the like, they are laminated and fired to integrate them without requiring an adhesive.

  Here, each piezoelectric element 140 is provided on the lower electrode film 143 provided on the vibration plate 123, the piezoelectric layer 144 provided independently in each pressure generation chamber 121, and each piezoelectric layer 144. And an upper electrode film 145. The piezoelectric layer 144 is formed by attaching or printing a green sheet made of a piezoelectric material.

  On the other hand, the flow path unit 130 includes an ink supply port forming substrate 131 joined to the pressure generating chamber bottom plate 124 of the actuator unit 120 and a reservoir forming substrate on which a reservoir 132 serving as a common ink chamber for the plurality of pressure generating chambers 121 is formed. 133 and a nozzle plate 135 in which nozzle openings 134 are formed.

  In the first and second embodiments, the ink jet recording head has been described as the liquid ejecting head. However, the present invention is widely intended for all liquid ejecting heads, and ejects liquid other than ink. Of course, it can also be applied. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

FIG. 3 is a cross-sectional view of the liquid ejecting head according to the first embodiment of the invention. FIG. 3 is a cross-sectional view of a main part of the liquid jet head according to the first embodiment of the invention. 1 is a schematic diagram illustrating an example of an ink jet recording apparatus using a liquid jet head according to the present invention. FIG. 6 is an exploded perspective view of a liquid jet head according to a second embodiment of the present invention. FIG. 6 is a cross-sectional view of a liquid jet head according to a second embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Inkjet recording head, 11 Pressure generation chamber, 12 Flow path formation board, 13 Nozzle opening, 14 Nozzle plate (joining member), 15 Diaphragm (joining member), 16 Flow path unit, 17 Piezoelectric element, 18 Piezoelectric element unit , 19 accommodating portion, 20 case head, 35 fixed substrate, 36 wiring, 37 circuit substrate, 41 wiring substrate, 50, 51 adhesive, 60 protective film, 61 ink contact surface, 62 peripheral portion

Claims (6)

A flow path forming substrate in which a liquid flow path having a pressure generation chamber communicating with a nozzle opening for ejecting liquid is formed, a diaphragm provided to face the pressure generation chamber, and the pressure generation chamber via the vibration plate A liquid ejecting head comprising pressure generating means for generating a pressure change,
A liquid ejecting head, wherein a protective film having resistance to a liquid in the pressure generating chamber is provided on a surface of the diaphragm on the pressure generating chamber side.   The liquid ejecting head according to claim 1, wherein the protective film is provided on a surface portion of the vibration plate on the pressure generation chamber side facing the liquid flow path of the flow path forming substrate. The liquid ejecting head according to claim 1, wherein the diaphragm includes an elastic film made of a resin film. The pressure generating unit includes a piezoelectric element forming member in which a piezoelectric material and an electrode forming material are vertically stacked and cut into comb teeth to form a piezoelectric element, and a fixed substrate on which the piezoelectric element forming member is fixed. The liquid ejecting head includes a case head in which the piezoelectric element unit is accommodated in a state in which a front end surface of the piezoelectric element is exposed, and the fixing substrate is fixed by an adhesive, The vibration plate is bonded to an end surface of the case head where the front end surface of the piezoelectric element is exposed, and the vibration plate fixes the front end surface of the piezoelectric element. 2. A liquid jet head according to item 1. The protective member is provided at a peripheral portion of an opening provided in a vibration plate for communicating an ink flow path provided in the case head and a pressure generation chamber of a flow path forming substrate. 4. The liquid jet head according to 4. The liquid ejecting head according to claim 5, wherein the protective member provided on the peripheral edge of the opening is formed by extending an adhesive for bonding the case head and the diaphragm.