JP2010182710A - Piezoelectric element unit, liquid injection head and liquid injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric element unit which can be easily connected to external wiring while reducing a cost, and to provide a liquid injection head and a liquid injection device. <P>SOLUTION: The piezoelectric element unit includes: a piezoelectric element 17; and a first substrate 35 which has one end surface 35a bonded to a first surface 34a of the piezoelectric element 17. The piezoelectric element 17 has: a second surface 34c which is a surface on the side of a second substrate 12 on the opposite side from the first surface 34a; a third surface 34b which is orthogonal to the first surface 34a and second surface 34c, and in which an individual external electrode 43 to be a connection portion for the external wiring 50 is formed; a common external electrode 44 which is provided on the external surface of the piezoelectric element 17; and a sloping surface which is provided at the border between the first surface 34a and third surface 34b, and is formed with a slope to the first surface 34a and third surface 34b. The sloping surface is a border portion 40 which decouples the individual external electrode 43 and common external electrode 44. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a piezoelectric element unit including a piezoelectric element and a fixed substrate that fixes the piezoelectric element, a liquid ejecting head, and a liquid ejecting apparatus.

  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 generation unit provided with a pressure generation chamber communicating with the nozzle opening and having a flow path formation substrate and a diaphragm provided on one side thereof, and a fixed substrate provided corresponding to each pressure generation chamber There is known one having a piezoelectric element unit having a piezoelectric element fixed to and a case head (structure) having a storage chamber to which the fixed substrate is fixed (see, for example, Patent Document 1).

  In such a piezoelectric element unit, the side surface of the end portion of the piezoelectric element and the side surface of the end portion of the fixed substrate are fixed to each other.

JP 2004-74740 A

  However, in order to fix the piezoelectric element to the side surface on the one end portion side of the fixed substrate, the piezoelectric element needs an inactive region (non-drive region) fixed to the fixed substrate. There is a problem that the piezoelectric element becomes longer depending on the region, resulting in higher costs.

  In addition, there is a problem that an inactive region fixed to the fixed substrate of the piezoelectric element requires an electrode patterned with high precision for connecting the individual electrode or common electrode of the piezoelectric element and the external wiring.

  Such a problem is not limited to the piezoelectric element unit mounted on the liquid ejecting head, and similarly exists in piezoelectric element units mounted on other apparatuses.

  In view of such circumstances, an object of the present invention is to provide a piezoelectric element unit, a liquid ejecting head, and a liquid ejecting apparatus that can be easily connected to an external wiring at a reduced cost.

An aspect of the present invention that solves the above-described problem includes a piezoelectric element and a first substrate having one end surface joined to the first surface of the piezoelectric element, and the piezoelectric element includes the first element. The second surface, which is the surface on the second substrate side opposite to the surface, and the first surface and the second surface are orthogonal to each other, and an individual external electrode serving as a connection portion with the external wiring is formed. A third surface, a common external electrode provided on the outer surface of the piezoelectric element, and a boundary between the first surface and the third surface, and the first surface and the third surface. The piezoelectric element unit has an inclined surface formed obliquely with respect to the surface, and the inclined surface serves as a boundary portion that divides the individual external electrode and the common external electrode.
In such an embodiment, compared to fixing the side surfaces of the piezoelectric element and the first substrate so as to overlap each other, an inactive region is substantially unnecessary in the piezoelectric element, and the piezoelectric element can be shortened. it can. Further, even if the external electrode is not patterned with high accuracy on the surface of the piezoelectric element by a photolithography method or the like, the external electrode can be easily divided by the boundary portion, and the cost can be reduced.

  Here, the piezoelectric element is formed by alternately laminating piezoelectric material layers and electrode material layers, and the first surface is fixed to the first substrate in a direction crossing the laminating direction. It is preferable that the piezoelectric material layer on the boundary side is thicker than other regions. According to this, it can suppress that an electrode material layer is cut | disconnected and an inactive area | region is formed when a boundary part is formed.

  In addition, it is preferable that an external wiring is connected to the individual external electrode, and the external wiring is electrically connected to the common external electrode via the first substrate. According to this, electrical connection between the external electrode and the piezoelectric element can be facilitated. In addition, the wiring pattern of the external wiring can be easily arranged and the external wiring can be downsized.

  Moreover, it is preferable that the first substrate has conductivity. According to this, the common external electrode and the external wiring can be easily electrically connected via the first substrate.

  In addition, the first substrate may be provided with a connection wiring that connects the external wiring and the common external electrode. According to this, the common external electrode and the external wiring can be electrically connected via the connection wiring provided on the first substrate.

  Further, the piezoelectric element is provided perpendicularly to an end face of the first substrate to which the piezoelectric element is fixed, and protrudes from a side surface provided across a plurality of piezoelectric elements, and the boundary portion is provided. It is preferable that the first surface of the piezoelectric element is provided in a region protruding from the first substrate. According to this, after fixing the first substrate and the piezoelectric element, the boundary portion can be easily formed by grinding or etching.

  Moreover, it is preferable that two rows of the piezoelectric elements are provided on one end surface of the first substrate in a direction intersecting with the parallel arrangement direction of the piezoelectric elements. According to this, the density of the piezoelectric element can be increased.

Furthermore, another aspect of the present invention provides the piezoelectric element unit according to any one of the above aspects, a diaphragm to which the second surface of the piezoelectric element of the piezoelectric element unit is fixed, and the second A liquid ejecting head comprising: a pressure generating chamber provided on a substrate and having one surface defined by the diaphragm and communicating with a nozzle opening.
In this aspect, since the repulsive force when the diaphragm of the piezoelectric element is pressed is directly received by the first substrate, the displacement of the piezoelectric element can be efficiently transmitted to the diaphragm to improve the liquid ejection characteristics. it can.

According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head according to the above aspect.
In this aspect, it is possible to realize a liquid ejecting apparatus that improves the liquid ejecting characteristics and improves the print quality.

FIG. 3 is a cross-sectional view of the recording head according to the first embodiment of the invention. It is a perspective view of the piezoelectric element unit which concerns on Embodiment 1 of this invention. It is the top view and sectional drawing of a piezoelectric element unit which concern on Embodiment 1 of this invention. It is sectional drawing of the piezoelectric element unit which concerns on Embodiment 2 of this invention. FIG. 6 is a cross-sectional view of a recording head according to Embodiment 2 of the invention. 1 is a schematic diagram illustrating an example of an ink jet recording apparatus according to an embodiment.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is a cross-sectional view of an ink jet recording head which is an example of a liquid jet head according to Embodiment 1 of the present invention.

  As shown in the drawing, the ink jet recording head I is provided with a flow path forming substrate 12 (second substrate) having a plurality of pressure generation chambers 11 and a plurality of nozzle openings 13 communicating with the pressure generation chambers 11. The flow path unit 16 includes a nozzle plate 14 and 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. The case head 20 is provided.

  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. A reservoir 22 to which ink is supplied via an ink introduction path (not shown) that is a liquid introduction path of the case head 20 is arranged outside the row of the pressure generation chambers 11 in the thickness direction. It is provided through. The reservoir 22 and each pressure generation chamber 11 communicate with each other via an ink supply path 23, and each pressure generation chamber 11 communicates with ink via an ink introduction path (not shown), the reservoir 22, and the ink supply path 23. Is supplied. 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 that penetrates the flow path forming substrate 12 is formed on the end side of the pressure generating chamber 11 opposite to the reservoir 22. In other words, in the present embodiment, the pressure generation chamber 11, the reservoir 22, the ink supply path 23, and the nozzle communication hole 24 are provided as the liquid flow path in the flow path forming substrate 12. 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 joined to one surface side of the flow path forming substrate 12, and each nozzle opening 13 is connected to each other via a nozzle communication hole 24 provided in the flow path forming substrate 12. It communicates with the pressure generation chamber 11.

  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 vibration plate 15 is formed by a composite plate of an elastic film 25 made of an elastic member such as a resin film and a support plate 26 that supports the elastic film 25, and the elastic film 25 side is formed on the flow path forming substrate 12. It is joined. For example, in this 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. That is, a thin portion 28 having a thickness smaller than that of the other regions is formed in a region of the vibration plate 15 facing the peripheral portion of each pressure generating chamber 11, and island portions 27 are provided inside the thin portion 28. ing. Further, in the present embodiment, in the region facing the reservoir 22 of the vibration plate 15, similarly to the thin portion 28, the support portion 26 is removed by etching, and the compliance portion 29 configured substantially only by the elastic film is provided. It has been. 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.

  Here, the piezoelectric element unit 18 will be described in detail. 2 is a perspective view of the piezoelectric element unit according to Embodiment 1 of the present invention, and FIG. 3 is a plan view of FIG. 2 and a cross-sectional view taken along line AA ′ thereof.

  As shown in FIGS. 2 and 3, the piezoelectric element unit 18 according to this embodiment includes a piezoelectric element forming member 34 having a row in which a plurality of piezoelectric elements 17 are arranged in parallel in the width direction, and a piezoelectric element forming member 34. And a fixed substrate 35 (first substrate) to which the base end surface of the other end portion is bonded so that the distal end portion (one end portion) side becomes a free end.

  As will be described in detail later, the piezoelectric element forming member 34 has a comb-like shape in which a plurality of rows of piezoelectric elements 17 are provided by slits 39 on the front end side of the rectangular parallelepiped. The distal end surface 34 c on which the piezoelectric element 17 is formed is fixed to the island portion 27, and the proximal end surface 34 a is fixed to the fixed substrate 35.

  The fixed substrate 35 is formed of a rectangular parallelepiped made of a metal material such as stainless steel (SUS), and is one end surface 35a on the flow path unit 16 side, that is, a surface facing the pressure generation chamber 11 side, and the tip of the piezoelectric element 17 It has one end surface 35a facing the same direction as the surface. A proximal end surface 34a that is a first surface of the piezoelectric element 17 is fixed to the one end surface 35a. That is, the piezoelectric element forming member 34 (piezoelectric element 17) and the fixed substrate 35 are integrated with the end faces 34a and 35a fixed to each other.

  The fixed substrate 35 has a side surface 35 b formed across the plurality of piezoelectric elements 17.

  Further, the side surface 34b of the piezoelectric element forming member 34 (piezoelectric element 17), that is, the base end surface 34a that is the first surface of the piezoelectric element 17, is orthogonal to the connection surface with the circuit board 50 that is external wiring described later. The third surface is fixed to the fixed substrate 35 in a state protruding from the side surface 35 b of the fixed substrate 35. This is because the circuit board 50 as the external wiring can be easily connected to the region (side surface 34b as the third surface) protruding from the fixed substrate 35 of the piezoelectric element forming member 34.

  Here, the piezoelectric element forming member 34 (piezoelectric element 17) will be described in detail. The piezoelectric element forming member 34 includes a piezoelectric material layer 36 and an electrode material layer constituting two poles of the piezoelectric element 17, that is, an individual internal electrode 37 constituting an individual electrode electrically independent of the adjacent piezoelectric element 17. In addition, a common internal electrode 38 that constitutes a common electrode that is electrically common to adjacent piezoelectric elements 17 is alternately stacked and stacked. In this embodiment, the stacking direction of the piezoelectric material layer 36, the individual internal electrode 37, and the common internal electrode 38 is the base end surface 34a fixed to the fixed substrate 35 from the front end surface 34c fixed to the island portion of the piezoelectric element 17. It is the same direction as the direction which intersects the direction which goes to, ie, the surface direction of tip end face 34c and base end face 34a.

  In the piezoelectric element forming member 34, a slit 39 is formed by a wire saw or the like on the distal end portion (free end) side opposite to the proximal end portion (base end surface) fixed to the fixed substrate 35, for example. . The distal end portion side of the piezoelectric element forming member 34 is cut into a comb-like shape corresponding to each pressure generating chamber 11 by the slit 39, thereby forming a row of each piezoelectric element 17. That is, the piezoelectric element forming member 34 is formed so that the plurality of piezoelectric elements 17 are integrated on the base end side.

  The slit 39 is a surface opposite to the base end surface 34a which is the first surface of the piezoelectric element forming member 34, and is fixed from the distal end surface 34c (second surface) side which is the surface on the pressure generating chamber 11 side. The base end surface 34a fixed to the substrate 35 is provided obliquely to the boundary portion 40 that is one corner (the bottom surface of the slit 39 on the base end surface 34a side is inclined with respect to the base end surface 34a). That is, at least a part of the base end surface 34a fixed to the fixed substrate 35 is integrally provided without being cut.

  The first surface (base end surface 34a) of the piezoelectric element 17 is orthogonal to the surface on which the individual internal electrode 37 and the common internal electrode 38 are exposed, as shown in FIG. 3B.

  Then, the base end surface 34a opposite to the tip end surface 34c contacting the island portion 27 of the piezoelectric element 17 (piezoelectric element forming member 34) is fixed to the one end surface 35a of the fixed substrate 35 as described above. 17 is fixed to the case head 20 via a fixed substrate 35.

  As described above, the piezoelectric element forming member 34 and the fixed substrate 35 are integrated by fixing the end faces 34a and 35a thereof, whereby the piezoelectric element forming member 34 can be shortened. That is, when the piezoelectric element (piezoelectric element forming member) and the fixed substrate are fixed in a state where the side surfaces overlap each other instead of the end faces, an inactive region is required for fixing the piezoelectric element forming member to the fixed substrate. Thus, the piezoelectric element (piezoelectric element forming member) becomes longer. In contrast, the piezoelectric element forming member 34 and the fixed substrate 35 are integrated by fixing their end faces 34a and 35a, so that the slit 39 for separating the piezoelectric elements 17 is substantially the length of the piezoelectric element forming member 34. It can be formed up to the direction. Therefore, the piezoelectric element forming member 34 only needs to be provided with a length substantially equal to that of the piezoelectric element 17 (substantially the active region), and the piezoelectric element forming member 34 can be shortened to reduce the cost.

  In the present embodiment, the slit 39 is provided so that the base end surface 34a side fixed to the fixed substrate 35 of the piezoelectric element forming member 34 is not completely cut. However, the present invention is not particularly limited thereto. The slit 39 may be provided so that the piezoelectric element forming member 34 can be completely cut. If the slit 39 is formed by a wire saw after fixing the piezoelectric element forming member 34 to the fixed substrate 35, the plurality of piezoelectric elements 17 can be easily fixed to the fixed substrate 35.

  In addition, positioning portions 41 are provided on both outer sides of the row of piezoelectric elements 17 in order to position each piezoelectric element 17. The positioning portion 41 is for positioning the piezoelectric element unit 18 with high accuracy with respect to the housing portion 19 of the case head 20 when the piezoelectric element unit 18 is incorporated into the ink jet recording head I.

  Here, the electrodes of the piezoelectric element 17 will be described. As shown in FIG. 3B, external electrodes 42 connected to the individual internal electrodes 37 and the common internal electrode 38 are formed on the outer surface of the piezoelectric element forming member 34. As described above, the external electrode 42 includes the individual external electrode 43 continuous from the distal end surface 34c to the one side surface and the common external electrode 44 provided on the proximal end surface 34a side.

  The individual internal electrodes 37 serving as the individual electrodes of each piezoelectric element 17 are basically provided over substantially the entire surface of the piezoelectric element forming member 34, but the common external electrode on the base end face 34 a side fixed to the fixed substrate 35. The electrode 44 is provided so as to be discontinuous without conducting. On the other hand, the common internal electrode 38 serving as the common electrode is basically provided over substantially the entire surface of the piezoelectric element forming member 34, but like the individual internal electrode 37, the individual external electrode is provided near the tip surface 34 c of the piezoelectric element 17. It is provided so as to be discontinuous without being electrically connected to the electrode 43. That is, almost all of the piezoelectric element 17 of the present embodiment is a vibration region that is vibrated, and no extra inactive region is required in the region fixed to the fixed substrate 35.

  The individual external electrode 43 and the common external electrode 44 are formed by a boundary portion 40 formed by removing a continuous electrode layer provided on the outer peripheral surface of the piezoelectric element forming member 34 together with a corner portion of the piezoelectric element forming member 34. It is formed by separating. Specifically, an electrode layer is provided over the distal end surface 34c and the proximal end surface 34a of the piezoelectric element forming member 34 and on one side surface 34b between the distal end surface 34c and the proximal end surface 34a. The boundary portion 40 is formed by removing the corner portions of the base end surface 34a and the side surface 34b fixed to the fixed substrate 35 together with the electrode layer by grinding or etching. That is, the boundary portion 40 is provided at the boundary between the base end surface 34a that is the first surface and the side surface 34b that is the third surface, and is an inclined surface that is formed obliquely with respect to the base end surface 34a and the side surface 34b. It has become.

  The individual external electrodes 43 and the common external electrode 44 are formed by separating the electrode layers by the boundary portion 40 thus formed. That is, the individual external electrode 43 and the common external electrode 44 are formed of the same layer, but are provided so as to be discontinuous (insulated) by the boundary portion 40. The plurality of slits 39 are formed with a length reaching the boundary portion 40 from the front end surface 34c of the piezoelectric element forming member 34, and the individual external electrodes 43 are separated from each other by the slits 39 and electrically connected to the piezoelectric elements 17 adjacent to each other. Independent. Further, the slit 39 is provided in the base end surface 34 a fixed to the fixed substrate 35 of the piezoelectric element forming member 34 without reaching the corner opposite to the boundary portion 40. Therefore, the common external electrode 44 is electrically in common with the piezoelectric elements 17 adjacent to each other. It should be noted that the common external electrode 44 and the individual external electrode 43 are formed by forming the slit 39 with a length that reaches the corner opposite to the boundary portion 40, that is, a length that completely separates the piezoelectric element forming member 34. Although separated in the same manner, the common external electrode 44 of this embodiment is electrically connected to the piezoelectric elements 17 adjacent to each other via the fixed substrate 35 because the common external electrode 44 is connected to the fixed substrate 35 having conductivity. )can do. Incidentally, the fixed substrate 35 and the piezoelectric element forming member 34 (piezoelectric element 17) are fixed to each other by a conductive fixing method such as a conductive adhesive or solder.

  In the present embodiment, the boundary portion 40 is provided at a corner portion protruding from one side surface of the fixed substrate 35 of the piezoelectric element forming member 34. Thus, after the piezoelectric element forming member 34 is fixed to the fixed substrate 35, the electrode layer and the corners of the piezoelectric element forming member 34 can be removed to easily form the boundary portion 40.

  The boundary 40 is formed by removing the corners of the piezoelectric element forming member 34. Therefore, the presence of the common internal electrode 38 in this region is not preferable because the connection between the common internal electrode 38 and the common external electrode 44 is disconnected by forming the boundary portion 40. Therefore, it is preferable to form the piezoelectric material layer 36 relatively thicker on the side where the boundary portion 40 is provided than in other regions. As a result, it is possible to prevent the active region from being reduced due to the formation of the inactive region (non-vibration region) by cutting the common internal electrode 38 and to prevent the inactive region from vibrating the active region. Can be reduced.

  In such a piezoelectric element unit 18, as described above, the individual external external electrode 42 is formed by simply forming the slit 39 and the boundary portion 40 in the piezoelectric element forming member 34 having the electrode layer formed on the outer peripheral surface. The electrode 43 and the common external electrode 44 are patterned. Therefore, it is not necessary to pattern the individual external electrode 43 and the common external electrode 44 on the outer peripheral surface of the piezoelectric element forming member 34 with high accuracy by photolithography or the like, and the cost can be reduced.

  In such a piezoelectric element unit 18, the individual external electrodes 43 are arranged in parallel on one side surface (one side surface between the distal end surface 34 c bonded to the island portion 27 and the proximal end surface 34 a bonded to the fixed substrate 35). In addition, a common external electrode 44 exists on the base end surface 34 a fixed to the fixed substrate 35. The individual external electrodes 43 in the vicinity of the boundary portion 40 of the piezoelectric element 17 are connected to a circuit board 50 that is an external wiring for supplying a signal for driving each piezoelectric element 17.

  For example, in this embodiment, the circuit board 50 is made of a chip-on-film (COF) on which a drive IC (not shown) for driving the piezoelectric element 17 is mounted. Then, each wiring 51 of the circuit board 50 is connected to the individual external electrode 43 of the piezoelectric element 17 by, for example, solder, anisotropic conductive material, or the like on the tip end side. Further, the wiring 51 of the circuit board is electrically connected to the fixed board 35 in a region opposite to the fixed board 35, and the common external electrode 44 of the piezoelectric element 17 is connected to the circuit board 50 through the fixed board 35. The wiring 51 is connected.

  Note that the fixed substrate 35 may be made of an insulating material. When the fixed substrate 35 made of an insulating material is used, a connection wiring or the like for electrically connecting the common external electrode 44 and the wiring 51 of the circuit substrate 50 may be provided on the surface of the fixed substrate 35.

  In this way, by connecting the common external electrode 44 to the circuit board 50 that is the external wiring via the fixed board 35, the connection area between the circuit board 50 and the individual external electrode 43 can be made relatively wide. That is, since the individual external electrodes 43 are also densified as the piezoelectric elements 17 are densified, the wiring 51 of the circuit board 50 is also densified. At this time, if the individual external electrode 43 and the common external electrode 44 are arranged side by side on the base end side of the piezoelectric element forming member 34, all the wirings must be arranged at the front end portion of the circuit board 50. Therefore, miniaturization and connection are difficult. On the other hand, if the common external electrode 44 is connected to the circuit board 50 via the fixed board 35 as in the present embodiment, these connections are in areas where the fixed board 35 and the circuit board 50 are close to each other. It becomes possible. Therefore, only the individual external electrode 43 needs to be connected at the tip of the circuit board 50, and the wiring 51 can be easily routed, and the circuit board 50 can be reduced in size and improved in connectivity.

  As shown in FIG. 1, such a piezoelectric element unit 18 is fixed to the housing portion 19 of the case head 20 on the side surface of the fixed substrate 35 opposite to the protruding side surface 35 b of the piezoelectric element forming member 34.

  Specifically, the piezoelectric element unit 18 is opposite to the projecting side surface 35 b of the piezoelectric element forming member 34 of the fixed substrate 35 in a state where the tip surface of the piezoelectric element 17 is in contact with the island portion 27 of the diaphragm 15. The side surface on the side is fixed to the accommodating portion 19 of the case head 20.

  The case head 20 is provided with an accommodating portion 19 that penetrates in a thickness direction in a region facing the island portion 27. A stepped portion 19a is provided in the accommodating portion 19, and the fixed substrate 35 is fixed in a state of being in contact with the stepped portion 19a.

  Such a case head 20 is made of, for example, a resin material. And the inner surface of the accommodating part 19 of the case head 20 is an alignment surface with which at least a part of the side surface of the piezoelectric element unit 18 abuts. In the present embodiment, the alignment surface is an inner surface on one side of the accommodating portion 19 in the direction in which the piezoelectric elements 17 are juxtaposed, and the direction in which the piezoelectric elements 17 are juxtaposed as at least part of the piezoelectric element unit 18 on this alignment surface. The piezoelectric element 17 is positioned with respect to the diaphragm 15 (island portion 27) by being held in a state where the one side surface (positioning portion 41) is in contact therewith. Note that a plurality of pressure generation chambers 11 are arranged in the short direction (the width direction, the direction in which the nozzle openings 13 are arranged in parallel), and the piezoelectric elements 17 correspond to the plurality of pressure generation chambers 11. A plurality of end faces are arranged in parallel in the short direction (width direction). That is, the piezoelectric elements 17 are arranged in a short direction on the end surface fixed to the island portion 27, and the piezoelectric elements 17 are arranged in parallel with the alignment surface, which is the side surface of the housing portion of the case head 20. Positioning of the short side direction of the piezoelectric element 17 and the short side direction of the island part 27 is performed by bringing the side surface (positioning part 41) on one side into contact. Incidentally, the width in the short direction of the island part 27 and the width in the short direction of the piezoelectric element 17 are both only about several tens of μm, and both are formed with substantially the same width. If positioning in the short direction between the ridge 17 and the island portion 27 is not performed with high accuracy, the displacement of the piezoelectric element 17 cannot be transmitted to the diaphragm 15 via the island portion 27, and ink ejection characteristics deteriorate. End up. In this embodiment, the short side direction of the piezoelectric element 17 and the short side direction of the island portion 27 are determined by abutting and positioning the alignment surface of the case head 20 and one side surface of the piezoelectric element 17 in the juxtaposed direction. Are positioned and fixed with high accuracy and have excellent ink ejection characteristics.

  Further, a wiring board 53 provided with a plurality of conductive pads 52 to which the respective wirings 51 of the circuit board 50 are connected is fixed on the case head 20, and the housing portion 19 of the case head 20 is connected to the wirings 53. The substrate 53 is substantially closed. The wiring board 53 has a slit-like opening 54 formed in a region facing the housing part 19 of the case head 20, and the circuit board 50 is drawn out of the housing part 19 from the opening part 54 of the wiring board 53. It is.

  Then, on the base end side of the circuit board 50 drawn out from the housing portion 19, each wiring 51 of the circuit board 50 is bonded to each conductive pad 52 of the wiring board 53. Specifically, in the state where the base end portion of the circuit board 50 drawn out from the opening 54 of the wiring board 53 to the outside of the housing part 19 is bent along the surface of the wiring board 53, each wiring 51 is connected to the wiring board 53. 53 are joined to the respective conductive pads 52.

  In such an ink jet recording head I, when ejecting ink droplets, the volume of each pressure generating chamber 11 is changed by deformation of the piezoelectric element 17 and the diaphragm 15 to eject ink droplets from a predetermined nozzle opening 13. It is like that. 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 individual internal electrode 37 and the common internal electrode 38 of the piezoelectric element 17 is released according to the recording signal supplied through the wiring board 53. . 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.

  At this time, the repulsive force when the piezoelectric element 17 presses the diaphragm 55 is directly received by the fixed substrate 35 that fixes the base end face 34a of the piezoelectric element 17 (piezoelectric element forming member 34). That is, when the diaphragm 15 is pressed, since the base end surface 34 a of the piezoelectric element 17 is regulated by the fixed substrate 35, the pressing force due to the displacement of the piezoelectric element 17 can be directly transmitted to the diaphragm 15. Thereby, excellent ink ejection characteristics can be obtained. Incidentally, when the piezoelectric element (piezoelectric element forming member) and the fixed substrate are fixed with the side surfaces overlapping each other instead of the end surfaces, the repulsive force of the piezoelectric element causes the bonding surface between the piezoelectric element and the fixed substrate to be fixed. Accepted to shear along the side. Therefore, the repulsive force of the piezoelectric element tends to escape in the shearing direction, and there is a possibility that the ink ejection characteristics are deteriorated.

(Embodiment 2)
FIG. 4 is a cross-sectional view of a piezoelectric element unit according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 4, the piezoelectric element unit 18 </ b> A of the present embodiment includes a fixed substrate 35 and two piezoelectric element forming members 34 (piezoelectric elements 17) fixed to one end surface 35 a of the fixed substrate 35.

  One piezoelectric element forming member 34 is used for one nozzle row, and this piezoelectric element forming member 34 has a portion divided into a plurality of piezoelectric elements 17 according to the number of nozzle openings 13. . Here, the two piezoelectric element forming members 34 are respectively fixed to both end portions in the short direction of the one end surface 35 a of the fixed substrate 35. Here, the short side direction of the one end face 35a is the direction in which the nozzle rows are arranged. Further, a leg portion 60 is provided between the two piezoelectric element forming members 34 on the one end surface 35 a to which the piezoelectric element forming member 34 of the fixed substrate 35 is fixed. The end surfaces of the leg portions 60 are formed so as to be flush with the front end surfaces 34 c of the two piezoelectric elements 17.

  Thus, even in the piezoelectric element unit 18A in which two rows of the piezoelectric elements 17 are provided on one fixed substrate 35, the piezoelectric elements 17 can be shortened to reduce the cost and the vibration of the piezoelectric elements 17 can be reduced. The repulsive force that presses the plate 15 can be directly received by the fixed substrate 35, and the piezoelectric characteristics can be improved.

  A circuit board 50 is connected to each piezoelectric element forming member 34 of the piezoelectric element unit 18A. The circuit board 50 is electrically connected to the piezoelectric elements 17 on both side surfaces of the fixed board 35. That is, two piezoelectric element forming members 34 are fixed to one fixed substrate 35, but the circuit boards 50 arranged along different side surfaces of the fixed substrate 35 are respectively connected to the two piezoelectric element forming members 34. Is connected. Therefore, the circuit board 50 can be easily connected to the two rows of piezoelectric elements 17.

  Here, an ink jet recording head I having such a piezoelectric element unit will be described. FIG. 5 is a cross-sectional view of an ink jet recording head which is an example of a liquid jet head according to Embodiment 2 of the present invention.

  As shown in FIG. 5, the ink jet recording head IA of this embodiment includes a flow path unit 16A, a piezoelectric element unit 18A, and a case head 20A.

  The case head 20A is provided with an accommodating portion 19A in which the piezoelectric element unit 18A is disposed. The flow path unit 16A is provided with a reservoir 22, which is a liquid flow path, an ink supply path 23, a pressure generation chamber 11, a nozzle communication hole 24, and the like corresponding to each piezoelectric element 17. That is, in this embodiment, since the piezoelectric element unit 18A is provided with two rows of the piezoelectric elements 17, the flow path unit 16A has liquid flow paths corresponding to the two rows of the piezoelectric elements 17. Two rows are provided.

  And each row | line | column of the piezoelectric element 17 of 18 A of piezoelectric element units is being fixed to the island part 27 provided in the area | region corresponding to the pressure generation chamber 11 of each liquid flow path. Further, the leg portion 60 is fixed via a diaphragm 15 in a region where the flow path forming substrate 12 between the two liquid flow paths exists.

  The case head 20A is provided with an accommodating portion 19A in which the piezoelectric element unit 18A is disposed. The case head 20 </ b> A and the fixed substrate 35 of the piezoelectric element unit 18 </ b> A are fixed on both side surfaces in the juxtaposed direction in the row of piezoelectric elements 17 (not shown). That is, the side surface of the fixed substrate 35 on which the piezoelectric element 17 protrudes is not fixed to the case head 20A.

  In the ink jet recording head IA having such a configuration, the two rows of the piezoelectric elements 17 are provided on the fixed substrate 35, so that the rows of the piezoelectric elements 17 adjacent to each other can be provided close to each other. Accordingly, it is possible to increase the density of the piezoelectric elements 17 and increase the density of the nozzle openings 13 to improve the printing quality.

  In addition, since the piezoelectric elements 17 are provided in two rows on the fixed substrate 35 and the leg portions 60 are provided between the rows of the piezoelectric elements 17, the rigidity of the piezoelectric element unit 18A can be maintained. That is, the repulsive force when the piezoelectric element 17 presses the diaphragm 15 is directly received by the fixed substrate 35, but is fixed to the case head 20A at both ends of the fixed substrate 35 in the direction in which the piezoelectric elements 17 are juxtaposed. If only, the entire flow path unit 16A is displaced with the displacement of the diaphragm 15, and there is a possibility that good ink ejection characteristics cannot be obtained. On the other hand, by providing the leg portion 60 and fixing the leg portion 60 to the flow path forming substrate 12 via the diaphragm 15, the leg portion 60 is in the direction opposite to the displacement direction of the piezoelectric element 17. 16A will be pressed, the deformation | transformation of the whole flow path unit 16A accompanying the displacement of the diaphragm 15 can be suppressed, and an ink discharge characteristic can be improved.

  Incidentally, the leg portion 60 is not provided with the slit 39 for separating the piezoelectric element 17. This can be realized by forming the slits 39 obliquely in the same manner as in the first embodiment described above when the slits 39 are formed in the piezoelectric element forming member 34 after the piezoelectric element forming member 34 is fixed to the fixed substrate 35. . Since the leg portion 60 is not separated by the slit 39 in this way, the rigidity of the leg portion 60 can be increased. Therefore, when the piezoelectric element 17 is driven, the flow path unit 16A is reliably pressed through the fixed substrate 35. Ink ejection characteristics can be improved.

  Further, since the piezoelectric element unit 18A described above can stand alone, the piezoelectric element unit 18A can be fixed to the flow path unit 16A before the case head 20A is fixed to the flow path unit 16A. Therefore, the positioning of the piezoelectric element unit 18A and the island portion 27 can be visually recognized from the side surface direction, and the positioning of the piezoelectric element unit 18A and the island portion 27 can be performed with high accuracy.

(Other embodiments)
As mentioned above, although each embodiment of this invention was described, the basic composition of this invention is not limited to what was mentioned above. For example, in the first and second embodiments described above, one or two piezoelectric element forming members 34 are provided on the fixed substrate 35. However, the present invention is not particularly limited to this. For example, three or more piezoelectric element forming members 34 are provided on one fixed substrate 35. The piezoelectric element forming member 34 may be provided. That is, the row of the piezoelectric elements 17 may be composed of two or more piezoelectric element forming members 34 in the direction in which the piezoelectric elements 17 are arranged.

  Further, in the first embodiment described above, the end surface in the direction intersecting the stacking direction in which the piezoelectric element forming members 34, the individual internal electrodes 37 and the common internal electrodes 38 are alternately stacked is used as the base end surface 34a. However, the present invention is not limited to this. For example, one end surface in the stacking direction of the piezoelectric element forming member 34, the individual internal electrode 37, and the common internal electrode 38 is used as a base end surface 34a and fixed to the fixed substrate 35. May be. In this case, the other end surface in the stacking direction may be the tip surface 34 c that is the second surface, and the tip surface 34 c may be fixed to the diaphragm 15.

  Furthermore, the fixed board | substrate of embodiment mentioned above can be utilized also as a thermal radiation member which has a thermal radiation function. That is, by using a material having a relatively high thermal conductivity as the fixed substrate 35, heat generated by driving the piezoelectric element 17 can be radiated through the fixed substrate 35. Further, as the fixed substrate 35, a heat radiating fin having an enlarged surface area may be used. That is, the fixed substrate 35 has both a function as a heat radiating member that radiates heat and a function as a fixing member that fixes the piezoelectric element 17 (piezoelectric element forming member 34) to the case heads 20 and 20A. You may do it. Of course, by contacting or bonding the circuit board 50, which is an external wiring, to the fixed board 35, the circuit board 50 can also function as a heat dissipation member for the driving IC provided on the fixed board 35. Of course, the fixed substrate 35 may have only a function as a heat radiating member.

  Note that the ink jet recording heads I and IA of the above-described embodiment constitute a part of a recording head unit including an ink flow path communicating with an ink cartridge and the like, and are mounted on the ink jet recording apparatus. FIG. 6 is a schematic view showing an example of the ink jet recording apparatus.

  As shown in FIG. 6, the ink jet recording apparatus II includes recording head units 1A and 1B each having an ink jet recording head I or IA. The recording head units 1A and 1B are detachably provided with cartridges 2A and 2B constituting ink supply means. A carriage 3 on which the recording head units 1A and 1B are mounted is attached to a carriage shaft 5 attached to the apparatus main body 4. It is provided 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 that 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 ink jet recording apparatus II described above, the ink jet recording head I or IA (head units 1A, 1B) is mounted on the carriage 3 and moves in the main scanning direction. However, the invention is not particularly limited thereto. For example, the present invention can also be applied to a so-called line type recording apparatus in which an ink jet recording head I or IA is fixed and printing is performed simply by moving a recording sheet S such as paper in the sub-scanning direction.

  In the first and second embodiments described above, an ink jet recording head has been described as an example of a liquid ejecting head. However, the present invention is intended for a wide range of liquid ejecting heads, and liquids other than ink. Needless to say, the present invention can also be applied to a method of manufacturing a liquid ejecting head that ejects water. 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. Further, although the ink jet recording apparatus II has been described as an example of the liquid ejecting apparatus, the liquid ejecting apparatus using the other liquid ejecting heads described above can also be used.

I, IA Inkjet recording head (liquid ejecting head), II Inkjet recording apparatus (liquid ejecting apparatus), 11 Pressure generating chamber, 16, 16A Channel unit, 17 Piezoelectric element, 18, 18A Piezoelectric element unit, 19, 19A Housing part, 20, 20A case head, 34 piezoelectric element forming member, 34a base end surface (first surface), 34b side surface (third surface), 34c distal end surface (second surface), 35 fixed substrate, 36 piezoelectric Material layer, 37 individual internal electrodes, 38 common internal electrodes, 40 border, 42 external electrodes, 43 individual external electrodes, 44 common external electrodes, 50 circuit board (external wiring), 53 wiring board, 60 legs

Claims (9)

A piezoelectric element; and a first substrate having one end surface joined to the first surface of the piezoelectric element;
The piezoelectric element is
The second surface which is the surface on the second substrate side opposite to the first surface, and the individual external which is orthogonal to the first surface and the second surface and serves as a connection portion with external wiring A third surface on which an electrode is formed;
A common external electrode provided on the external surface of the piezoelectric element;
An inclined surface provided at a boundary between the first surface and the third surface and formed obliquely with respect to the first surface and the third surface;
The piezoelectric element unit characterized in that the inclined surface serves as a boundary portion that divides the individual external electrode and the common external electrode.   The piezoelectric element is formed by alternately laminating piezoelectric material layers and electrode material layers, and is provided with the first surface fixed to the first substrate in a direction intersecting with the laminating direction. 2. The piezoelectric element unit according to claim 1, wherein the piezoelectric material layer on the boundary side is thicker than other regions.   The external wiring is connected to the individual external electrode, and the external wiring is electrically connected to the common external electrode via the first substrate. The piezoelectric element unit described.   The piezoelectric element unit according to claim 3, wherein the first substrate has conductivity.   4. The piezoelectric element unit according to claim 3, wherein the first substrate is provided with connection wiring for connecting the external wiring and the common external electrode.   The piezoelectric element is provided so as to protrude from a side surface formed across a plurality of piezoelectric elements and orthogonal to an end surface of the first substrate to which the piezoelectric element is fixed, and the boundary portion includes the piezoelectric element. The piezoelectric element unit according to claim 1, wherein the piezoelectric element unit is provided in a region protruding from the first substrate on the first surface of the element.   The one end surface of the first substrate is provided with two rows of the piezoelectric elements in a direction intersecting with a direction in which the piezoelectric elements are arranged side by side. The piezoelectric element unit according to one item.   The piezoelectric element unit according to any one of claims 1 to 7, a diaphragm to which the second surface of the piezoelectric element of the piezoelectric element unit is fixed, and the second substrate provided on the second substrate, A liquid ejecting head comprising: a pressure generating chamber having one surface defined by a diaphragm and communicating with a nozzle opening.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 8.

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