JP2019171681A - Liquid discharge head - Google Patents

Abstract

A liquid discharge head capable of easily supplying a charge through another through hole to a portion where the charge has been supplied through the through hole even if a disconnection occurs in one through hole. A bypass wiring including a plurality of conductor layers is formed on an upper piezoelectric layer at a position overlapping with an extending portion of an intermediate common electrode in a laminating direction. At least two through holes 168 are formed in a region where the position of the bypass wiring in the scanning direction is the same as the extending portion 244 of the intermediate common electrode 241. [Selection diagram] FIG.

Description

  The present invention relates to a liquid ejection head that ejects a liquid such as ink toward a medium.

  As a liquid ejecting apparatus, an ink jet head of an ink jet printer that forms an image by ejecting ink onto a recording medium while moving relative to the recording medium is known. For example, in the ink jet printer shown in Patent Document 1, an ink jet head having a piezoelectric body in which a plurality of piezoelectric material layers (ceramic sheets) are laminated is disclosed.

JP 2011-212865

  The inkjet head of Patent Document 1 has a piezoelectric body in which a plurality of piezoelectric material layers are stacked. A plurality of individual surface electrode arrays are formed on the uppermost piezoelectric material layer, and a common electrode is formed on the intermediate piezoelectric material layer. In the uppermost piezoelectric material layer, a surface electrode for supplying a potential to the common electrode of the intermediate piezoelectric material layer is also formed. The surface electrode extends between the end of the piezoelectric material layer and the individual surface electrode array in a direction orthogonal to the extending direction of the individual surface electrode array. A plurality of through holes are formed between the surface electrode and the common electrode, and the surface electrode and the common electrode are electrically connected through the conductive material filled in the through hole. Thereby, the electric potential in each part of a common electrode can be made constant.

  However, if an electrical disconnection occurs, for example, because a sufficient amount of conductive material was not filled in one through hole, the charge was supplied through that through hole to another location. It is difficult to supply charges.

  The object of the present invention is to supply electric charge through the through-hole even when it is electrically disconnected because, for example, a sufficient amount of conductive material is not filled in one through-hole. It is an object to provide a liquid discharge head capable of easily supplying a charge to a location through another through hole.

According to an aspect of the present invention, a piezoelectric body in which a plurality of piezoelectric layers are stacked, the first end and the second end separated in a first direction orthogonal to the stacking direction of the plurality of piezoelectric layers, and the stack A piezoelectric body having a third end and a fourth end separated in a direction and a second direction orthogonal to the first direction;
A common electrode formed along a first surface which is a surface orthogonal to the stacking direction;
A bypass wiring formed along a second surface that is perpendicular to the stacking direction and whose position in the stacking direction is different from the position in the stacking direction of the first surface;
The second surface or a surface orthogonal to the stacking direction, the position in the stacking direction being formed along a third surface different from the position in the stacking direction of the first surface and the second surface. A plurality of individual electrodes,
The plurality of individual electrodes constitute a plurality of individual electrode rows arranged with a gap between the first end and the second end,
The plurality of individual electrode rows include a first individual electrode row, a second individual electrode row arranged in the first direction with the first individual electrode row, and the first individual electrode row includes: The first individual electrode row is located between the first end and the second individual electrode row in the first direction, and the second individual electrode row is located between the first individual electrode row and the second end in the first direction. Position to,
The plurality of individual electrodes constituting the first individual electrode row are arranged along the second direction,
The plurality of individual electrodes constituting the second individual electrode row are arranged along the second direction,
The common electrode is
A first extension portion extending in the first direction between the fourth end in the second direction and one of the individual electrodes closest to the fourth end in the second direction;
A second extending portion extending in the second direction from the first extending portion toward the third end;
A plurality of first projecting portions projecting in the one direction from the second extending portion toward the first end or the second end, each constituting the first individual electrode array in the stacking direction A plurality of first protrusions that at least partially overlap the individual electrodes;
A third extending portion located between the second extending portion and the second end in the first direction and extending in the second direction from the first extending portion toward the third end; ,
A plurality of second projecting portions projecting in the one direction from the third extending portion toward the first end or the second end, each constituting the second individual electrode array in the stacking direction A plurality of second protrusions that at least partially overlap the individual electrodes,
The bypass wiring extends in the first direction between the fourth end in the second direction and one of the individual electrodes closest to the fourth end in the second direction, and At least a portion overlaps the first extension in the stacking direction;
The piezoelectric body includes a first through hole extending in the stacking direction between the conductor layer and the first extension portion, and a stack between the conductor layer and the first extension portion. A second through hole extending in the direction,
Provided is a liquid discharge head, wherein the conductor layer and the first extending portion are electrically connected by a conductive material disposed in the first through hole and the second through hole. Is done.

  According to the above configuration, the bypass wiring and the first extending portion of the common electrode are connected by the conductive material disposed in the first through hole and the second through hole. One extending portion is electrically connected to at least two places. Therefore, even if an electrical disconnection occurs due to a sufficient amount of conductive material not filling one through hole, the disconnected through hole in the common electrode is charged through the other through hole. It is possible to easily supply electric charge to the portion that has been supplied. Therefore, the reliability of electrical connection between the bypass wiring and the common electrode can be improved.

1 is a plan view illustrating an outline of an inkjet printer 1 according to an embodiment. 2 is a schematic view of an inkjet head 5 and a wiring member 50 according to the present embodiment. FIG. It is a schematic exploded view of the laminated body which concerns on this embodiment. (A) is a schematic sectional drawing of the scanning direction of the inkjet head which concerns on this embodiment, (b) is a schematic sectional drawing of the conveyance direction of the inkjet head which concerns on this embodiment. 4 is a top view of an upper piezoelectric layer 140 according to the present embodiment. FIG. (A) is explanatory drawing to which a part of upper surface of the upper piezoelectric layer 140 which concerns on this embodiment was expanded, (b) is the schematic for demonstrating an electrical path | route. 4 is a top view of an intermediate piezoelectric layer 240 according to the present embodiment. FIG. 3 is a top view of a lower piezoelectric layer 340 according to the present embodiment. FIG. (A) is a schematic diagram showing the overlap between the upper piezoelectric layer 140 and the intermediate piezoelectric layer 240 according to the present embodiment, and (b) is a schematic diagram showing the overlap between the upper piezoelectric layer 140 and the lower piezoelectric layer 340 according to the present embodiment. FIG. FIG. 5 is a schematic cross-sectional explanatory view showing the joining of the piezoelectric body 40 and the COF 51 according to the present embodiment. (A)-(c) is the schematic for demonstrating the deformation | transformation which generate | occur | produces in a piezoelectric material. (A)-(c) is the schematic for demonstrating DC junction. (A), (b) is the schematic for demonstrating DC junction. (A) is the schematic for demonstrating the conductor layer 190 for barriers, (b) is the schematic for demonstrating the conductor layer 191 for barriers. It is the schematic for demonstrating the conductor layer 160S concerning a change form.

<Schematic configuration of printer>
An embodiment of the present invention will be described. As shown in FIG. 1, the ink jet printer 1 mainly includes a platen 2, a carriage 3, a carriage drive mechanism 4, an ink jet head 5, a transport mechanism 6, a controller 7, and an ink supply unit 8. Yes.

  A recording sheet 100 as a recording medium is placed on the upper surface of the platen 2. The carriage 3 is configured to reciprocate in the left-right direction (hereinafter also referred to as the scanning direction) along the two guide rails 10 and 11 in a region facing the platen 2 by the carriage driving mechanism 4. The carriage drive mechanism 4 includes a belt 12, two rollers 13 disposed so as to sandwich the platen 2 on both sides in the scanning direction of the platen 2, and a carriage drive motor 14. A belt 12 is connected to the carriage 3. The belt 12 is stretched between two rollers 13 that are arranged apart in the scanning direction so as to form an oval ring that is long in the scanning direction when viewed from above. As shown in FIG. 1, the right roller 13 is connected to the rotation shaft of the carriage drive motor 14. By rotating the carriage drive motor 14, the belt 12 can be rotated around the two rollers 13. Accordingly, the carriage 3 coupled to the belt 12 can be reciprocated in the scanning direction.

  The inkjet head 5 is attached to the carriage 3 and reciprocates in the scanning direction together with the carriage 3. The ink supply unit 8 includes four ink cartridges 17 each storing ink of four colors (black, yellow, cyan, magenta), a cartridge holder 18 to which the four ink cartridges 17 are mounted, a tube (not shown), Is provided. The inkjet head 5 and the four ink cartridges 17 are connected through a tube (not shown). As a result, four colors of ink are supplied from the ink supply unit 8 to the inkjet head 5.

  A plurality of nozzles 23 are formed on the lower surface of the inkjet head 5 (the surface on the other side of the paper in FIG. 1) (see FIG. 3). The plurality of nozzles 23 eject the ink supplied from the ink cartridge 17 toward the recording paper 100 placed on the platen 2.

  The transport mechanism 6 includes two transport rollers 18 and 19 disposed so as to sandwich the platen 2 in the front-rear direction. The transport mechanism 6 transports the recording paper 100 placed on the platen 2 forward (hereinafter also referred to as a transport direction) by two transport rollers 18 and 19.

  The controller 7 includes a ROM (Read Only Memory), a RAM (Random Access Memory), an ASIC (Application Specific Integrated Circuit) including a control circuit, and the like. The controller 7 executes various processes such as printing on the recording paper 100 by the ASIC according to the program stored in the ROM. For example, in the printing process, the controller 7 controls the inkjet head 5, the carriage drive motor 14, and the like based on a print command input from an external device such as a PC, and prints an image on the recording paper 100. Specifically, an ink discharge operation for discharging ink while moving the inkjet head 5 in the scanning direction together with the carriage 3 and a transport operation for transporting the recording paper 100 in the transport direction by the transport rollers 18 and 19 are alternately performed. To do.

  The ink jet head 5 mainly includes a flow path unit 20, a diaphragm 30, a piezoelectric body 40, and a wiring member 50 (see FIG. 2). 2 and 3, the flow path unit includes five metal plates 21 </ b> A to 21 </ b> E and a nozzle plate 22. Further, the vibration plate 30 is joined on the metal plate 21 </ b> A of the flow path unit 20. In the following description, a combination of the flow path unit and the diaphragm 30 is referred to as a laminate 60. That is, as shown in FIG. 3, the laminated body 60 includes the vibration plate 30, five metal plates 21 </ b> A to 21 </ b> E, and the nozzle plate 22, and these plates are laminated and joined in this order. It is. In the following description, the direction in which these plates are stacked in the stacked body 60 is referred to as a stacking direction.

  The diaphragm 30 is a substantially rectangular metal plate that is long in the transport direction. The metal plates 21A to 21E and the nozzle plate 22 are also substantially rectangular plates having the same planar shape. As shown in FIGS. 2 and 3, four openings 31 a to 31 d serving as ink supply ports for supplying ink to a manifold, which will be described later, are formed at the end of the vibration plate 30 in the transport direction. . The four openings 31a to 31d are arranged side by side in the scanning direction (left-right direction). The opening 31a is an ink supply port for yellow ink, the opening 31b is an ink supply port for magenta ink, the opening 31c is an ink supply port for cyan ink, and the opening 31d is an ink supply port for black ink. It is. There are three manifolds for black ink, and the opening 31d is a supply port for supplying black ink to the three manifolds. On the other hand, there is one manifold for color ink (each ink of cyan, magenta, and yellow), and each of the openings 31a to 31c is a supply port for supplying one of the color inks to one manifold. It is. Therefore, the area of the opening 31d is larger than the areas of the openings 31a to 31c.

  The plate 21A is a metal plate in which openings functioning as a plurality of pressure chambers 26 are regularly formed. In addition, openings are respectively formed at positions overlapping the four openings 31 a to 31 d of the diaphragm 30. The plurality of pressure chambers 26 constitute a pressure chamber row 25 arranged in the conveying direction at an arrangement pitch P, and 12 such pressure chamber rows 25 are formed. The twelve pressure chamber rows 25 are arranged side by side in the scanning direction (left-right direction).

  Of the twelve pressure chamber rows 25, six rows are color ink pressure chamber rows 25, and the remaining six rows are black ink pressure chamber rows 25. As shown in FIG. 2, six black ink pressure chamber rows 25 are provided so as to be aligned with the openings 31d in the transport direction. The six pressure chamber rows 25 for color ink have two pressure chamber rows 25 for cyan ink, two pressure chamber rows 25 for magenta ink, and two pressure chamber rows 25 for yellow ink. is doing. Two rows of cyan ink pressure chambers 25 are provided so as to be aligned with the openings 31c in the transport direction. Two rows of magenta ink pressure chambers 25 are provided so as to be aligned with the openings 31b in the transport direction. Two rows of yellow ink pressure chambers 25 are provided so as to be aligned with the openings 31a in the transport direction.

  Between the two pressure chamber rows 25 for cyan ink, the position of the pressure chamber 26 in the transport direction is shifted by a half (P / 2) of the arrangement pitch P of each pressure chamber row 25. The same applies to the two magenta ink pressure chamber rows 25 and the two yellow ink pressure chamber rows 25. Although not clearly shown in FIG. 2, the pressure chamber rows 25 for six black inks are arranged so that the positions of the pressure chambers 26 in the transport direction are 1/6 of the arrangement pitch P of the pressure chamber rows 25. It is shifted by (P / 6).

  The plate 21B has a communication hole 28a that forms a flow path from the manifold 27 (common ink chamber) described later to each pressure chamber 26 and a communication hole 28b that forms a flow path from each pressure chamber 26 to each nozzle 23 described later. Is formed. A communication passage 28c that communicates the pressure chamber 26 and the manifold 27 is formed as a recess on the upper surface of the plate 21C. Furthermore, the plate 21 </ b> C is formed with a communication hole 28 d that forms a flow path from the manifold 27 to the pressure chamber 26 and a communication hole 28 e that forms a flow path from the pressure chamber 26 to the nozzle 23. In addition, openings are formed at positions where the plates 21B and 21C overlap with the four openings 31a to 31d of the diaphragm 30, respectively. Through holes 29a and 29b forming the manifold 27 are formed in the plates 21D and 21E, and communication holes 29c and 29d forming a flow path from the pressure chamber 26 to the nozzle 23 are formed, respectively.

  The nozzle plate 22 is a synthetic resin (for example, polyimide resin) plate, and nozzles 23 are formed corresponding to the pressure chambers 26 formed in the plate 21A.

  These diaphragm 30, plates 21A to 21E, and nozzle plate 22 are stacked and joined, so that the manifold 23 reaches the nozzle 23 via the pressure chamber 26 as shown in FIGS. A plurality of flow paths are formed. At the same time, an ink supply channel for supplying ink to the manifold 27 is also formed.

  Since the vibration plate 30 and the plates 21A to 21E are metal plates, they can be joined by metal diffusion bonding. Further, since the nozzle plate 22 is a resin plate, it is joined to the plate 21E by an adhesive or the like instead of metal diffusion joining. The nozzle plate 22 may be a metal plate, and in that case, the nozzle plate 22 can be joined by metal diffusion bonding similarly to the other plates. Alternatively, all the plates may be joined with an adhesive or the like.

<Piezoelectric body 40>
For example, as shown in FIGS. 2 and 3, the piezoelectric body 40 is disposed on the diaphragm 30. The piezoelectric body 40 has a substantially rectangular planar shape. As shown in FIGS. 4A and 4B, a plurality of piezoelectric elements 401 are formed on the piezoelectric body 40. The plurality of piezoelectric elements 401 are provided corresponding to the plurality of pressure chambers 26, respectively. Each piezoelectric element 401 cooperates with the diaphragm 30 to change the volume of the corresponding pressure chamber 26. As a result, each piezoelectric element 401 cooperates with the diaphragm 30 to apply pressure to the ink in the corresponding pressure chamber 26 and to discharge energy from the nozzles 23 communicating with the pressure chamber 26. Has been granted.

  Hereinafter, the configuration of the piezoelectric body 40 will be described. 4A and 4B, the piezoelectric body 40 has three piezoelectric layers (an upper piezoelectric layer 140, an intermediate piezoelectric layer 240, a lower piezoelectric layer 340), an individual electrode (upper electrode) 141, an intermediate A common electrode (intermediate electrode) 241 and a lower common electrode (lower electrode) 341 are provided. On the diaphragm 30, a lower piezoelectric layer 340, an intermediate piezoelectric layer 240, and an upper piezoelectric layer 140 are laminated in this order. The three piezoelectric layers 140, 240, and 340 are made of a piezoelectric material mainly composed of lead zirconate titanate (PZT), which is a mixed crystal of lead titanate and lead zirconate. Alternatively, the three piezoelectric layers 140, 240, and 340 may be formed of a lead-free piezoelectric material that does not contain lead. A lower common electrode 341 is disposed on the upper surface of the lower piezoelectric layer 340, an intermediate common electrode 241 is disposed on the upper surface of the intermediate piezoelectric layer 240, and the individual electrode 141 and the conductor layer 160 are disposed on the upper surface of the upper piezoelectric layer 140. 165, etc. are arranged.

  In the following description, both end portions in the scanning direction of the upper piezoelectric layer 140 are referred to as end portions 140L and 140R, and both end portions in the transport direction are referred to as end portions 140U and 140D (see FIG. 5). Both end portions in the scanning direction of the intermediate piezoelectric layer 240 are called end portions 240L and 240R, and both end portions in the transport direction are called end portions 240U and 240D (see FIG. 7). Both end portions in the scanning direction of the lower piezoelectric layer 340 are referred to as end portions 340L and 340R, and both end portions in the transport direction are referred to as end portions 340U and 340D (see FIG. 8).

  As shown in FIG. 5, six terminals 180 </ b> R arranged in the transport direction are formed at the end portion 140 </ b> R of the upper piezoelectric layer 140 in the scanning direction. As shown in FIG. 7, terminals 280 </ b> R are formed at positions where the end portions 240 </ b> R in the scanning direction of the intermediate piezoelectric layer 240 overlap with the five terminals 180 </ b> R in the stacking direction. The terminals 180R and 280R are formed of the same conductive material (silver palladium (AgPd)) as the individual electrode 141 described later. Further, two through holes 181R are formed at positions overlapping the respective terminals 180R of the upper piezoelectric layer 140. Two through holes 281R are formed at positions overlapping the terminals 280R of the intermediate piezoelectric layer 240, respectively. Note that the through hole 181R and the through hole 281R are positioned so as to be continuous in the stacking direction. The two continuous through holes 181R and 281R define a through hole that penetrates the upper piezoelectric layer 140 and the intermediate piezoelectric layer 240. The through holes 181R and 281R are filled with the same conductive material (silver palladium (AgPd)) as the terminals 180R and 280R. As will be described later, a process of filling the through holes 181R and 281R with a conductive material and a process of forming the terminals 180R and 280R by a method such as screen printing are performed as a series of processes. The conductive material filled in the through hole 281R is electrically connected to the lower common electrode 341 (extended portion 343 (see FIG. 8) described later). That is, the lower common electrode 341 is drawn to the terminal 180R on the upper surface of the upper piezoelectric layer 140 through the conductive material in the through holes 281R and 181R.

  As shown in FIG. 5, five terminals 180 </ b> L arranged in the transport direction are formed at the end portion 140 </ b> L of the upper piezoelectric layer 140 in the scanning direction. The terminal 180L is formed of the same conductive material (silver palladium (AgPd)) as the individual electrode 141 and the terminal 180R described later. Two through holes 181L are formed at positions overlapping the terminals 180L of the upper piezoelectric layer 140, respectively. The inside of the through hole 181L is filled with the same conductive material (silver palladium (AgPd)) as the terminal 180L. The conductive material filled in the through hole 181L is electrically connected to the intermediate common electrode 241 (extended portion 243 described later (see FIG. 7)). That is, the intermediate common electrode 241 is drawn to the terminal 180L on the upper surface of the upper piezoelectric layer 140 through the conductive material in the through hole 181L.

  Bumps 182L and 182R connected to terminals (not shown) of COF 51 described later are formed on the terminals 180L and 180R, respectively. By connecting the bumps 182L and 182R to the COF 51, a predetermined potential (for example, 0V) can be supplied from the driver IC 58 to the intermediate common electrode 241 and the lower common electrode 341 through the COF 51.

<Individual electrode 141>
As shown in FIGS. 4A and 4B, a plurality of individual electrodes 141 are formed at positions corresponding to the plurality of pressure chambers 26 on the upper surface of the upper piezoelectric layer 140, respectively. The individual electrode 141 can be formed of a conductive material such as silver palladium (AgPd), platinum (Pt), or iridium (Ir), for example. The individual electrode 141 of this embodiment is formed of silver palladium (AgPd). As shown in FIG. 5, 12 individual electrode rows 150 are formed corresponding to 12 pressure chamber rows 25. Twelve individual electrode rows 150 are arranged in the scanning direction. Each individual electrode row 150 of each individual electrode row includes 37 individual electrodes 141 arranged at a predetermined pitch P in the transport direction. In the following description, the nth element counted from the one close to the end 140L of the upper piezoelectric layer 140 in the scanning direction is simply called the nth element from the left. Similarly, in the intermediate piezoelectric layer 240 and the lower piezoelectric layer 340, the nth one counted from the one close to the end 240 </ b> L (see FIG. 7) of the intermediate piezoelectric layer 240 in the scanning direction, and the lower piezoelectric layer 340. Everything that is nth from the one near the end 340L (see FIG. 8) is called the nth from the left. The first and second individual electrode rows 150 from the left are shifted from each other by ½ of the arrangement pitch P in the transport direction. Similarly, the third and fourth individual electrode rows 150 from the left and the fifth and sixth individual electrode rows 150 from the left are shifted from each other by ½ of the arrangement pitch P in the transport direction. . Further, the seventh and eighth individual electrode rows 150 from the left are shifted from each other by 1/6 of the arrangement pitch P in the transport direction. Similarly, the eighth and ninth individual electrode rows 150 from the left, the ninth and tenth individual electrode rows 150 from the left, the tenth and eleventh individual electrode rows 150 from the left, and the eleventh and twelfth electrodes from the left The individual electrode rows 150 are shifted from each other by 1/6 of the arrangement pitch P in the transport direction.

  Among the 12 individual electrode arrays 150, the first, second, third and fourth, fifth and sixth individual electrode arrays 150 from the left are respectively the cyan ink pressure chamber array 25 and magenta. This corresponds to the pressure chamber row 25 for ink and the pressure chamber row 25 for yellow ink. In addition, the sixth, eighth, ninth, tenth, eleventh, and twelfth individual electrode rows from the left correspond to the pressure chamber row 25 for black ink.

  As shown in FIGS. 5 and 6A, each individual electrode 141 has either a wide portion 142 (an example of a first portion) having a rectangular planar shape, or a left-right direction (scanning direction) from the wide portion 142. A narrow portion 143 (an example of a second portion) extending in one direction. Each narrow portion 143 is formed with a bump 191 that is electrically joined to a contact (not shown) provided on a COF 51 of the wiring member 50 described later. As shown in FIG. 5, among the 12 individual electrode rows 150, in the individual electrode 141 constituting the first, third, fifth, eighth, tenth, and twelfth individual electrode rows 150 from the left, The narrow portion 143 extends in the scanning direction from the end portion 142R in the scanning direction of the wide portion 142 toward the end portion 140R of the upper piezoelectric layer 140. Among the 12 individual electrode rows 150, the individual electrodes 141 constituting the second, fourth, sixth, seventh, ninth, and eleventh individual electrode rows 150 from the left are arranged in the scanning direction of the wide portion 142. A narrow portion 143 extends in the scanning direction from the end 142L toward the end 140L of the upper piezoelectric layer 140. Note that the narrow portion 143 extends on the opposite side in the scanning direction to the nozzle formed in the corresponding pressure chamber 26 (see FIG. 4A). That is, in the pressure chambers 26 constituting the first, third, fifth, eighth, tenth, and twelfth pressure chamber rows 25 from the left, the upper piezoelectric layer of each pressure chamber 26 is located above the center in the scanning direction. The nozzle 23 is formed at a position close to the end 140L of 140. In the pressure chambers 26 constituting the second, fourth, sixth, seventh, ninth, and eleventh pressure chamber rows 25 from the left, the upper piezoelectric layer 140 of each pressure chamber 26 is located more than the center in the scanning direction. The nozzle 23 is formed at a position close to the end portion 140R.

  Among the individual electrode rows 150 adjacent in the scanning direction, (1) the first individual electrode row 150 and the second individual electrode row 150 from the left, and (2) the third individual electrode row 150 from the left and the left The fourth individual electrode row 150 from the left, (3) the fifth individual electrode row 150 from the left and the sixth individual electrode row 150 from the left, and (4) the eighth individual electrode row 150 from the left and the ninth from the left. The fifth individual electrode row 150, (5) the tenth individual electrode row 150 from the left and the eleventh individual electrode row 150 from the left, respectively, have a narrow portion 143 of the individual electrode 141 constituting the individual electrode row 150. Are arranged so as to face each other in the scanning direction. Therefore, the distance (XL1) in the scanning direction of the wide portion 142 of the individual electrode 141 constituting these two individual electrode rows 150 is the two individual electrode rows in which the narrow portion 143 is not facing in the scanning direction. This is larger than the size (XL2) of the interval in the scanning direction of the wide portion 142 of the individual electrode 141 constituting 150. The distance (XL3) in the scanning direction between the sixth individual electrode row 150 from the left and the wide portion 142 of the individual electrode 141 constituting the seventh individual electrode row 150 from the left is from XL1 and XL2. Is even bigger. This is because the first to sixth individual electrode rows 150 from the left correspond to the pressure chamber rows 25 for color ink, and the seventh to twelfth individual electrode rows 150 from the left correspond to pressure chamber rows for black ink. This is due to the fact that it corresponds to 25.

  Between the sixth individual electrode row 150 from the left and the seventh individual electrode row 150 from the left in the scanning direction, a dummy electrode 171 arranged at the same arrangement pitch P as the arrangement pitch P of the individual electrodes 141 in the transport direction. A dummy electrode array 170 is provided. The dummy electrode 171 is made to correspond to the wide portion 142 of the individual electrode 141, and the size and shape of the dummy electrode 171 are substantially the same as the size and shape of the wide portion 142 of the individual electrode 141. is there. Note that since the potential is not supplied from the driver IC 58 to the dummy electrode 171, a portion corresponding to the narrow portion 143 of the individual electrode 141 is not provided. The distance between the wide portion 142 of the individual electrode 141 constituting the sixth individual electrode row 150 from the left and the dummy electrode 171 in the scanning direction and the width of the individual electrode 141 constituting the seventh individual electrode row 150 from the left The distance in the scanning direction between the portion 142 and the dummy electrode 171 is XL1.

<Conductor layer 160>
As shown in FIG. 5, seven conductor layers 160 are formed between the end portion 140U of the upper piezoelectric layer 140 and the individual electrode 141 closest to the end portion 140U of each individual electrode row 150 in the transport direction. Has been. The seven conductor layers 160 are formed at positions overlapping with the extending portions 242 of the intermediate common electrode 241 in the stacking direction. The conductor layer 160 is formed of the same conductive material (silver palladium (AgPd)) as that of the individual electrode 141. As shown in FIGS. 5 and 6A, the seven conductor layers 160 are arranged in a line in the scanning direction. The positions of the seven conductor layers 160 in the transport direction are all the same. In other words, the distance in the transport direction between the end portion 140U of the upper piezoelectric layer 140 and the conductor layer 160 is the same.

  The position in the scanning direction of the first conductor layer 160 from the left is the same as the position in the scanning direction of the individual electrode 141 of the first individual electrode row 150 from the left. The position in the scanning direction of the second conductor layer 160 from the left is the same as the position in the scanning direction of the individual electrode 141 of the second and third individual electrode rows 150 from the left. The position in the scanning direction of the third conductor layer 160 from the left is the same as the position in the scanning direction of the individual electrode 141 of the fourth and fifth individual electrode rows 150 from the left. The position in the scanning direction of the fourth conductor layer 160 from the left is the same as the position in the scanning direction of the individual electrode 141 of the sixth individual electrode row 150 from the left. The position in the scanning direction of the fifth conductor layer 160 from the left is the same as the position in the scanning direction of the individual electrode 141 of the seventh and eighth individual electrode rows 150 from the left. The position in the scanning direction of the sixth conductor layer 160 from the left is the same as the position in the scanning direction of the individual electrodes 141 of the ninth and tenth individual electrode rows 150 from the left. The position in the scanning direction of the seventh conductor layer 160 from the left is the same as the position in the scanning direction of the individual electrodes 141 of the eleventh and twelfth individual electrode rows 150 from the left.

  The shape of the first and fourth conductor layers 160 from the left is substantially the same as the shape of the individual electrode 141. Similarly to the individual electrode 141, the first and fourth conductor layers 160 from the left are a wide portion 162 having a rectangular planar shape, and a narrow portion 163 extending from the wide portion 162 in either the left-right direction (scanning direction). With. The length in the scanning direction of the wide portion 162 of the first and fourth conductive layers 160 from the left is the same as the length in the scanning direction of the wide portion 142 of the individual electrode 141. The length in the transport direction of the wide portion 162 of the first and fourth conductor layers 160 from the left is the same as the length of the wide portion 142 of the individual electrode 141 in the transport direction. The shapes of the second, third, and fifth to seventh conductor layers 160 from the left are the same, and each of them has a wide portion 162 having a rectangular planar shape and 2 extending from the wide portion 162 in the left-right direction (scanning direction). Two narrow portions 163. As shown in FIG. 5, the length in the scanning direction of the wide portion 162 of the second, third, fifth to seventh conductor layers 160 from the left is twice the length of the wide portion 142 of the individual electrode 141 in the scanning direction. Bigger than. The length of the wide portion 162 of the second, third, fifth to seventh conductor layers 160 from the left is the same as the length of the wide portion 142 of the individual electrode 141 in the transport direction.

<Conductor layer 165>
As shown in FIGS. 5 and 6A, between the wide portions 162 of the two conductor layers 160 adjacent in the scanning direction in the scanning direction, the conductive portions that connect the end portions 162L in the conveying direction of the wide portions 162. A body layer 165 is provided. In addition, a conductor layer 165 that connects the first conductor layer 160 from the left and the terminal 180L is also provided between the first conductor layer 160 from the left and the terminal 180L. The conductor layer 165 is formed of a conductive adhesive such as silver paste, and is bonded to the COF 51 (see FIG. 10) by DC bonding described later. As will be described later, the conductor layer 165 is formed by crushing a plurality of bumps arranged at predetermined intervals with the COF 51 from above, thereby forming a conductor layer 165 in which the deformed bumps are connected in a daisy chain.

<Through hole 168>
As shown in FIGS. 5 and 6 (a), six through holes 168 are formed in the substantially central portion in the scanning direction of the wide portion 162 of the second conductor layer 160 from the left. The six through holes 168 are arranged in two rows in the scanning direction, and three through holes 168 are arranged in the transport direction in each row. The positions of the six through holes 168 in the scanning direction are the same as the positions in the scanning direction of the first extending portion 244 from the left of the later-described intermediate common electrode 241. In FIG. 6A, the extended portion 244 of the intermediate common electrode 241 is indicated by a dotted line. For simplification of the drawing, the extended portion 242 and the protruding portion 245 of the intermediate common electrode 241 are not shown. As shown in FIG. 6A, the positions of the six through holes 168 in the scanning direction are the same as the positions of the extending portions 244 in the scanning direction. Furthermore, the six through holes 168 are located inside the extending portion 242 in the scanning direction. Similarly, the wide portions 162 of the third, fifth, and seventh conductor layers 160 from the left are each formed with six through holes 168. The position of any through hole 168 in the scanning direction is the same as the position of the extending portion 244 in the scanning direction. Further, as shown in FIG. 6A, three through holes 168 are formed in the substantially central portion in the scanning direction of the wide portion 162 of the first conductor layer 160 from the left. Similarly, three through-holes 168 are also formed in the substantially central portion in the scanning direction of the wide portion 162 of the fourth conductor layer 160 from the left.

  An extension portion 242 of an intermediate common electrode 241 described later is provided at a position of the intermediate piezoelectric layer 240 that overlaps the through hole 168 (see FIG. 7). Each through hole 168 is filled with the same conductive material (silver palladium (AgPd)) as that of the conductor layer 160, and the conductive material in the through hole 168 is electrically connected to the extending portion 242 of the intermediate common electrode 241. ing. As described above, all the conductor layers 160 are electrically connected to each other through the conductor layer 165, and are also electrically connected to the terminal 180L. Thereby, the intermediate common electrode 241 and the terminal 180 </ b> L are electrically connected through the conductive layers 160 and 165 and the conductive material in the through hole 168.

  As described above, the conductor layer 160 in which the plurality of through holes 168 are formed is arranged so as to be dispersed at a plurality of locations separated in the scanning direction. Therefore, not only one electrical path from the terminal 180L to the intermediate common electrode 241 but also a bypass path is formed. That is, the conductors 160 and 165 and the conductor in the through hole 168 form a plurality of bypass wirings extending from the terminal 180L to the intermediate common electrode 241.

  For example, as shown in FIG. 6B, the charge supplied from the terminal 180L is supplied to the intermediate common electrode 241 via a plurality of electrical paths. In FIG. 6B, the electrical path on the upper surface of the upper piezoelectric layer 140 is illustrated by a solid arrow, and the electrical path on the upper surface of the intermediate piezoelectric layer 240 is illustrated by a dotted arrow. In FIG. 6B, the individual electrodes 141 and the dummy electrodes 198 are not shown and some hatching is omitted for simplification of the drawing. As shown in FIG. 6B, a part of the electric charge supplied from the terminal 182L is supplied to the extending portion 243 of the intermediate common electrode 241 through one of the two through holes 181L, and further 1 from the left. To the second extension 245. Further, another part of the electric charge supplied from the terminal 182L passes through the first conductor layer 165 from the left and reaches the first conductor layer 160 from the left. Then, a part of the electric charge reaching the first conductor layer 160 from the left reaches the second conductor layer 160 from the left through the second conductor layer 165 from the left. Part of the electric charge that has reached the second conductive layer 160 from the left is supplied to the extended portion 242 of the intermediate common electrode 241 through one of the six through holes 168 formed in the conductive layer 160. , And supplied to the first extension 245 from the left.

  As described above, electric charges can be supplied to one extension portion 245 through an electrical path through the upper piezoelectric layer 140 and an electrical path through the intermediate piezoelectric layer 240. Note that the electrical paths illustrated in FIG. 6B are merely examples, and there are a plurality of electrical paths that are not illustrated. Although not shown in FIG. 6B, when a large amount of charge is required in the first extending portion 245 from the left, one of the charges supplied to another extending portion 245 is used. The portion may be supplied to the first extension portion 245 from the left via the extension portion 242.

<Dummy electrodes 198, 199>
As shown in FIGS. 5 and 6, a dummy electrode 198 made of the same conductive material as that of the individual electrode 141 is disposed between the conductor layer 160 and the individual electrode row 150 in the transport direction. Further, as described above, since the individual electrode rows 150 are arranged so as to be shifted from each other in the transport direction, the interval in the transport direction between the conductor layer 160 and the individual electrode rows 150 varies depending on the individual electrode rows 150. ing. Similarly, the distance between the end portion 140 </ b> D and the individual electrode row 150 in the transport direction also differs depending on the individual electrode row 150. The length of the dummy electrode 198 in the transport direction is set according to the distance between the conductor layer 160 and the individual electrode row 150 in the transport direction. The length of the dummy electrode 199 in the transport direction is set according to the distance between the end portion 140D and the individual electrode row 150 in the transport direction. Specifically, the distance in the transport direction between the dummy electrode 198 and the conductor layer 160 and the distance in the transport direction between the dummy electrode 198 and the individual electrode 141 are equal to each other between the two individual electrodes 141 adjacent in the transport direction. The length in the transport direction of each dummy electrode 198 is set so as to be the same as the interval.

  As shown in FIG. 5, among the individual electrodes 141 of the individual electrode row 150, the distance between the individual electrode 141 closest to the end portion 140 </ b> D in the transport direction and the end portion 140 </ b> D in the transport direction is the same as the individual electrode 141. A dummy electrode 199 made of a conductive material is disposed. The shape of the dummy electrode 199 is the same as that of the individual electrode 144. The distance in the transport direction between the individual electrode 141 and the dummy electrode 199 closest to the end portion 140D in the transport direction is the same as the distance between the two individual electrodes 141 adjacent in the transport direction.

  By providing such dummy electrodes 198 and 199, a characteristic difference does not occur between the individual electrodes 141 located at both ends in the conveyance direction of the individual electrode row 150 and the other individual electrodes 141.

<Intermediate common electrode 241>
As shown in FIGS. 4A and 4B, an intermediate common electrode 241 is formed on the upper surface of the intermediate piezoelectric layer 240. As shown in FIG. 7, the intermediate common electrode 241 includes an extension part 242 extending in the scanning direction (left-right direction) so as to cover the end part 240 U in the transport direction of the intermediate piezoelectric layer 240, and the intermediate piezoelectric layer 240. An extending portion 243 extending in the transport direction so as to cover the end portion 240L in the scanning direction, and six extending from the extending portion 242 toward the end portion 240D in the transport direction of the intermediate piezoelectric layer 240 in the transport direction. Extending portions 244 and a plurality of protruding portions 245 protruding from the extending portions 244 to both sides in the scanning direction. A plurality of projecting portions 245 also project from the extending portion 243 toward the end portion 240 </ b> R of the intermediate piezoelectric layer 240 in the scanning direction.

  The extending part 242 and the extending part 243 are in positions that do not overlap the pressure chamber 26 and the individual electrode 141 in the stacking direction. As shown in FIG. 9A, the extending portion 244 includes two individual electrode rows that are adjacent in the scanning direction so as not to overlap the wide portion 142 of the individual electrode 141 constituting the individual electrode row 150 in the stacking direction. 150 extends in the transport direction between the wide portions 142 of the individual electrodes 141 composing 150. In FIG. 6, among the six extending portions 244, the first extending portion 244 from the left passes between the wide portions 142 constituting the second and third individual electrode rows 150 from the left in the scanning direction. It extends in the transport direction. The second extending portion 244 from the left side extends in the transport direction so as to pass between the wide portions 142 constituting the fourth and fifth individual electrode rows 150 from the left. The third extending portion 244 from the left side extends in the transport direction so as to pass between the wide portion 142 constituting the sixth individual electrode row 150 from the left and the dummy electrode 171 constituting the dummy electrode row 170 in the scanning direction. It is extended. The fourth extending portion 244 from the left side extends in the transport direction so as to pass between the wide portions 142 constituting the seventh and eighth individual electrode rows 150 from the left in the scanning direction. The fifth extending portion 244 from the left side extends in the transport direction so as to pass between the wide portions 142 constituting the ninth and tenth individual electrode rows 150 from the left. The sixth extending portion 244 from the left extends in the transport direction so as to pass between the wide portions 142 constituting the eleventh and twelfth individual electrode rows 150 from the left in the scanning direction.

  The third extending portion 244 from the left is located at the boundary between the pressure chamber row 25 for color ink and the pressure chamber row 25 for black ink, and between the pressure chamber rows 25 in the scanning direction as described above. The width is wider than the other extending portions 244 in accordance with the increase in the interval. The remaining five extending portions 244 have the same width. Regarding the five extending portions 244 excluding the third extending portion 244 from the left, the individual electrodes 141 constituting the two individual electrode rows 150 sandwiching each extending portion 244 in the scanning direction are narrow in the scanning direction. The part 143 is arranged so as to extend to the opposite side. That is, with respect to the five extending portions 244 excluding the third extending portion 244 from the left, the scanning of the wide portion 142 of the individual electrode 141 constituting the two individual electrode rows 150 sandwiching each extending portion 244 in the scanning direction. The size of the interval in the direction is L2. In accordance with this, the width in the scanning direction of the five extending portions 244 excluding the third extending portion 244 from the left is also L2.

  Next, the positional relationship among the pressure chamber 26, the individual electrode 141, and the intermediate common electrode 241 will be described with reference to FIG. In FIG. 9A, four rows of individual electrodes arranged in the scanning direction are shown, but here, individual electrodes included in the second row of individual electrodes from the left in FIG. 9A. These positional relationships will be described by taking 141 as an example the pressure chamber 26 and the intermediate common electrode 241 that overlap in the stacking direction. In order to make the drawing easy to see, the intermediate common electrode 241 and the conductor layer 260 formed on the intermediate conductor layer 240 are indicated by solid lines, and the pressure chamber 26, the individual electrode 141, and the like are indicated by dotted lines.

  The length of the pressure chamber 26 in the scanning direction is longer than the length of the wide portion 142 of the individual electrode 141 in the scanning direction. The entire length of the individual electrode 141 including the wide portion 142 and the narrow portion 143 in the scanning direction is longer than the length of the pressure chamber 26 in the scanning direction. The length of the protruding portion 245 of the intermediate common electrode 241 in the scanning direction is substantially the same as the length of the wide portion 142 of the individual electrode 141 in the scanning direction.

  The nozzle 23 is located closer to the end 26R than the end 26L in the scanning direction of the pressure chamber in the scanning direction. The end portion 26R of the pressure chamber 26 is located between the end portion 244L and the end portion 244R in the scanning direction of the extending portion 244 in the scanning direction. The end portion 26L of the pressure chamber 26 is located between the end portion 142L of the wide portion 142 and the end portion 143L of the narrow portion 143 in the scanning direction in the scanning direction. The end 245L in the scanning direction of the protruding portion 245 of the intermediate common electrode 241 and the end 142L of the wide portion 142 are substantially at the same position in the scanning direction. The end portion 141R in the scanning direction of the wide portion 142 of the individual electrode 141, the end portion 244L of the extending portion 244, and the nozzle 23 are at substantially the same position in the scanning direction.

  The center position in the transport direction of the protrusion 245 of the intermediate common electrode 241, the center position in the transport direction of the pressure chamber 26, and the center position in the transport direction of the wide portion 142 of the individual electrode 141 are substantially the same in the transport direction. . The length of the pressure chamber 26 in the transport direction is longer than the length of the protrusion 245 of the intermediate common electrode 241 in the transport direction, and the ratio of these lengths is about 2: 1. For this reason, both end portions of the pressure chamber 26 in the transport direction (about ¼ of the length of the pressure chamber in the transport direction) do not overlap the protruding portion 245 of the intermediate common electrode 241 in the stacking direction. Further, the length of the wide portion 142 of the individual electrode 141 in the transport direction is longer than the length of the pressure chamber 26 in the transport direction.

<Lower common electrode 341>
As shown in FIG. 8, a lower common electrode 341 is formed on the upper surface of the lower piezoelectric layer 340. As shown in FIG. 8, the lower common electrode 341 includes an extending portion 342 extending in the scanning direction (left-right direction) so as to cover an end 340 </ b> D in the transport direction of the lower piezoelectric layer 340, and the lower piezoelectric layer 340. An extending portion 343 extending in the transport direction so as to cover the end portion 340R in the scanning direction, and six extending in the transport direction from the extending portion 342 toward the end portion 340U in the transport direction of the lower piezoelectric layer 340 It has the extended part 344 and the some protrusion part 345 which protrudes from the extended part 344 to the both sides of a scanning direction. A plurality of projecting portions 345 also project from the extending portion 343 in the scanning direction toward the end portion 340L of the lower piezoelectric layer 340 in the scanning direction. The extending portion 342 is located at a position that does not overlap the pressure chamber 26 and the individual electrode 141 in the stacking direction. Further, it is in a position that does not overlap with the intermediate common electrode 241 in the stacking direction.

  Each of the six extending portions 344 includes individual electrodes constituting two individual electrode rows 150 adjacent to each other in the scanning direction so as not to overlap with the wide portion 142 of the individual electrode 141 constituting the individual electrode row 150 in the stacking direction. 141 extends in the transport direction between the wide portions 142. In FIG. 8, among the six extending portions 344, the first extending portion 344 from the left passes between the wide portions 142 constituting the first and second individual electrode rows 150 from the left in the scanning direction. It extends in the transport direction. The second extending portion 344 from the left extends in the transport direction so as to pass between the wide portions 142 constituting the third and fourth individual electrode rows 150 from the left. The third extending portion 344 from the left side extends in the transport direction so as to pass between the wide portions 142 constituting the fifth and sixth individual electrode rows 150 from the left in the scanning direction. The third extending portion 344 from the left side is a conveyance direction so as to pass between the dummy electrode 171 constituting the dummy electrode row 170 and the wide portion 142 constituting the seventh individual electrode row 150 from the left in the scanning direction. It extends to. The fifth extending portion 344 from the left side extends in the transport direction so as to pass between the wide portions 142 constituting the eighth and ninth individual electrode rows 150 from the left. The sixth extending portion 344 from the left extends in the transport direction so as to pass between the wide portions 142 constituting the tenth and eleventh individual electrode rows 150 from the left.

  The fourth extending portion 344 from the left is located at the boundary between the pressure chamber row 25 for color ink and the pressure chamber row 25 for black ink. The six extending portions 344 have the same width. Regarding the five extending portions 344 excluding the fourth extending portion 344 from the left, the individual electrodes 141 constituting the two individual electrode rows 150 sandwiching each extending portion 344 in the scanning direction are narrow portions 143 in the scanning direction. Are arranged so as to face each other (see FIG. 5). That is, with respect to the five extending portions 344 excluding the fourth extending portion 344 from the left, the scanning of the wide portion 142 of the individual electrode 141 constituting the two individual electrode rows 150 sandwiching each extending portion 344 in the scanning direction. The size of the interval in the direction is XL1. Also, between the dummy electrode 171 constituting the dummy electrode row 170 and the wide portion 142 of the individual electrode 141 constituting the seventh individual electrode row 150 sandwiching the fourth extending portion 344 from the left in the scanning direction. The distance in the scanning direction is also XL1. In accordance with this, the width of the six extending portions 344 in the scanning direction is also XL1.

  Next, the positional relationship among the pressure chamber 26, the individual electrode 141, and the lower common electrode 341 will be described with reference to FIG. In FIG. 9B, four rows of individual electrodes arranged in the scanning direction are illustrated, but here, individual electrodes included in the second row of individual electrodes from the left in FIG. 9B. 141, and the positional relationship between the pressure chamber 26 and the lower common electrode 341 overlapping with each other in the stacking direction will be described as an example. In order to make the drawing easier to see, the lower common electrode 341 and the through hole 360 formed in the lower conductor layer 340 are indicated by solid lines, and the pressure chamber 26, the individual electrode 141, and the like are indicated by dotted lines.

  The length of the protruding portion 345 of the lower common electrode 341 in the scanning direction is substantially the same as the length of the wide portion 142 of the individual electrode 141 in the scanning direction.

  The end portion 26L of the pressure chamber 26 is located between the end portion 344L and the end portion 344R in the scanning direction of the extending portion 344 in the scanning direction. The end portion 26R of the pressure chamber 26 is substantially at the same position in the scanning direction as the end portion 345R of the protruding portion 345 of the lower common electrode 341 in the scanning direction. An end 344R of the extending portion 344 of the lower common electrode 341 is between the end 26L of the pressure chamber 26a and the end 142L of the wide portion 142 of the individual electrode 141 in the scanning direction.

  As described above, the end 142L of the wide portion 142 is substantially in the same position in the scanning direction as the end 245L of the protruding portion 245 of the intermediate common electrode 241 in the scanning direction (see FIG. 9A). Therefore, it can be seen that the protruding portion 245 of the intermediate common electrode 241 and the extending portion 344 of the lower common electrode 341 do not overlap in the stacking direction. Further, the end portion 244L of the extending portion 244 of the intermediate common electrode 241 is substantially at the same position as the nozzle 23 in the scanning direction (see FIG. 9A). Therefore, it can be seen that the protruding portion 345 of the lower common electrode 341 and the extending portion 244 of the intermediate common electrode 241 overlap in the scanning direction.

  The center position in the transport direction of the protrusion 345 of the lower common electrode 341 substantially coincides with the center position of the gap between two pressure chambers 26 adjacent in the transport direction in the transport direction. The length in the transport direction of the gap between two pressure chambers 26 adjacent to each other in the transport direction is shorter than the length in the transport direction of the protrusion 345 of the lower common electrode 341. Therefore, both end portions of the pressure chamber 26 in the transport direction overlap with the protruding portion 345 of the lower common electrode 341 in the stacking direction. Note that the length in the transport direction of the overlapping portion of the pressure chamber 26 and the protrusion 345 of the lower common electrode 341 in the stacking direction is shorter than ¼ of the length of the pressure chamber 26 in the transport direction. As described above, at both ends of the pressure chamber 26 in the transport direction, about ¼ of the length of the pressure chamber 26 in the transport direction does not overlap with the protruding portion 245 of the intermediate common electrode 241 in the stacking direction. Therefore, the protruding portion 345 of the lower common electrode 341 and the protruding portion 245 of the intermediate common electrode 241 do not overlap in the stacking direction.

  As described above, the center position of the pressure chamber 26 in the transport direction and the center position of the wide portion 142 of the individual electrode 141 substantially coincide with each other in the transport direction, and the wide portion of the individual electrode 141. The length of 142 in the transport direction is longer than the length of pressure chamber 26 in the transport direction. Therefore, both end portions of the wide portion 142 in the transport direction overlap with the protruding portions 345 of the lower common electrode 341 in the stacking direction. The length of the overlapping portion of the wide portion 142 and the protruding portion 345 of the lower common electrode 341 in the stacking direction is the length of the overlapping portion of the overlapping portion of the pressure chamber 26 and the protruding portion 345 of the lower common electrode 341 in the stacking direction. Longer than the direction length.

<Wiring member 50>
As shown in FIG. 2, the wiring member 50 includes a COF 51 (Chip On Film) and a driver IC 58 disposed in the COF 51. A contact (not shown) formed on the COF 51 is electrically connected to a bump 191 (see FIG. 6) provided on the narrow portion 143 of each individual electrode 141, and is individually connected to each individual electrode 141. Potential can be set. Further, as described above, the driver IC 58 can set a predetermined constant potential for the intermediate common electrode 241 and the lower common electrode 341. As shown in FIG. 10, the thickness of the COF 51 is not uniform. The COF 51 includes a substrate 52, a plurality of wirings 53 disposed on the substrate 52, and a solder resist layer 54 for protecting the wirings 53. The wirings 53 are not uniformly arranged on the substrate 52, and there are a portion where the wirings 53 are dense and a portion where the wirings 53 are not arranged. The portion of the COF 51 where the wirings 53 are dense is thicker than the portion where the wirings 53 are not provided by the amount covered with the solder resist layer 54. In the following description, a portion of the COF 51 where the wiring 53 is covered with the solder resist layer 54 is referred to as a film thickness portion 51A, and a portion where the wiring 53 of the COF 51 is not present is referred to as a thin film portion 51B. Call. The COF 51 is disposed such that the film thickness portion 51A and the conductor layer 160 overlap in the stacking direction, and the film thin portion 51B and the conductor layer 165 overlap in the stacking direction.

<Driving of piezoelectric element 401>
As described above, the piezoelectric body 40 is a substantially rectangular plate-like member that is disposed on the diaphragm 30 so as to cover the plurality of pressure chambers 26 (see, for example, FIG. 2). A plurality of piezoelectric elements 401 provided corresponding to the plurality of pressure chambers 26 are formed in the piezoelectric body 40. Hereinafter, driving of the piezoelectric element 401 will be described. A portion of the upper piezoelectric layer 140 sandwiched between the individual electrode 141 and the intermediate common electrode 241 in the stacking direction (hereinafter referred to as the first active portion 41 (see FIGS. 4A and 4B)) is in the stacking direction. Polarized. Further, a portion of the upper piezoelectric layer 140 and the intermediate piezoelectric layer 240 sandwiched between the individual electrode 141 and the lower common electrode 341 in the stacking direction (hereinafter referred to as the second active portion 42 (see FIGS. 4A and 4B)). )) Is also polarized in the stacking direction. Here, in a state where the driver IC 58 is energized, a predetermined first potential (for example, 24V) is always applied to the intermediate common electrode 241 and a predetermined second potential (for example, 0V) is always applied to the lower common electrode 341. Applied. Further, a first potential and a second potential are selectively applied to each individual electrode 141. Specifically, when ink is not ejected from the pressure chamber 26 corresponding to a certain individual electrode 141, the second potential is applied to the individual electrode 141. At this time, since no potential difference is generated between the individual electrode 141 and the lower common electrode 341, the second active part 42 is not deformed. However, a potential difference (here, 24 V) between the first potential and the second potential is generated between the individual electrode 141 and the intermediate common electrode 241. Thereby, the 1st active part 41 is changing so that it may become convex on the lower side (pressure chamber 26 side).

  When ink is ejected from the pressure chamber 26 corresponding to a certain individual electrode 141, the first potential is applied to the individual electrode 141, and then the second potential is returned. That is, a pulse-like voltage signal that increases from the second potential to the first potential and returns to the second potential after a predetermined time has elapsed is applied to the individual electrode 141. When the first potential is applied to the individual electrode 141, the potential difference between the individual electrode 141 and the intermediate common electrode 241 disappears, so the first electrode that has been deformed to protrude downward (on the pressure chamber 26 side) is used. The active part 41 tries to return to the original state. At this time, since the first active portion 41 is displaced upward, the volume of the pressure chamber 26 is thereby increased. At this time, a potential difference (24 V in this case) is generated between the individual electrode 141 and the lower common electrode 341, and the second active portion 42 is deformed so as to lift the central portion of the pressure chamber 26 upward. The increase in the volume of can be increased. Next, when the potential of the individual electrode 141 returns to the second potential, there is no potential difference between the individual electrode 141 and the lower common electrode 341 as described above, so the second active portion 42 returns. A potential difference (here, 24 V) between the first potential and the second potential is generated between the individual electrode 141 and the intermediate common electrode 241 again. Thereby, the 1st active part 41 deform | transforms so that it may protrude below (pressure chamber 26 side). At this time, the ink in the pressure chamber 26 is ejected from the nozzles 23 by the pressure applied to the pressure chamber 26.

<About warping deformation of piezoelectric material layer>
In general, when a metal thin film layer such as an individual electrode, an intermediate common electrode, or a lower common electrode is formed on the surface of the piezoelectric material layer, the metal thin film layer is formed on the piezoelectric material sheet by printing or the like. It is firing. As shown in FIG. 11C, thermal stress in the compression direction remains in the fired piezoelectric layer. In the following description, the thermal stress remaining in the fired piezoelectric layer is simply referred to as residual stress. The strength of the residual stress increases as the area of the metal thin film layer increases. In the stacking direction, when the magnitude of the residual stress remaining on the upper side across the neutral plane NP is different from the magnitude of the residual stress remaining on the lower side, the piezoelectric body 40 according to the difference between these residual stresses. Is deformed to warp in the stacking direction.

  The distance in the stacking direction from the neutral plane NP to the upper surface of the upper piezoelectric layer 140 on which the individual electrode 141 is formed is the distance in the stacking direction from the neutral plane NP to the upper surface of the intermediate piezoelectric layer 240 and the neutral plane NP. Greater than the distance from the top surface of the lower piezoelectric layer 340. Therefore, when an excess metal thin film layer is formed on the upper surface of the upper piezoelectric layer 140 and fired, warping deformation of the piezoelectric body 40 is increased.

  In the above embodiment, the conductor layer 165 formed on the upper surface of the upper piezoelectric layer 140 is formed by bumps for bonding to the COF 51 by DC bonding, and thus does not contribute to warping deformation of the piezoelectric body 40. . The reason will be described below.

  In general, CC bonding (Cover Coat bonding), DC bonding (Direct Connection bonding), and the like are known as methods for bonding a metal thin film layer such as an electrode formed on the surface of a piezoelectric material layer and COF. . In the CC bonding, first, bumps are formed on a metal thin film layer such as an electrode by a technique such as printing (screen printing), and the formed bumps are cured. Next, a thermosetting adhesive is printed on the COF at a position facing the bump. And after aligning the bump formed on the metal thin film layer and the thermosetting adhesive disposed on the surface of the COF, the bump and the thermosetting adhesive are joined by heating and pressing. . As described above, in the CC bonding, the bump and the COF are bonded by the thermosetting adhesive. On the other hand, in the DC bonding employed in the present embodiment, the bumps formed on the metal thin film layer and the COF are directly bonded without using a thermosetting adhesive.

  The DC junction will be described with reference to FIGS. 12A to 12C and FIGS. 13A and 13B. First, as shown in FIG. 12A, a piezoelectric body in which a lower piezoelectric layer 340, an intermediate piezoelectric layer 240 in which an intermediate common electrode 241 is formed, and an upper piezoelectric layer 140 in which a through hole 168 is formed are stacked. Prepare 40. Although not shown in FIG. 12A, a lower common electrode 341 is formed on the lower piezoelectric layer 340, and a terminal 280R and a through hole 281 are formed on the intermediate piezoelectric layer 240. Further, through holes 181L and 181R are also formed in the upper piezoelectric layer 140. Next, as shown in FIG. 12B, a mask M having an opening having substantially the same diameter as the through hole 168 is overlaid on the upper piezoelectric layer 140, and a conductive material (silver palladium (AgPd)) is placed on the upper portion. The piezoelectric layer 140 is applied. Although not shown in FIG. 12B, the mask M also has openings having substantially the same diameter as the through holes 181L and 181R, and the mask M is disposed above the upper piezoelectric layer 140 in alignment. At this time, the through holes 168, 181L, and 181R are exposed from the mask M. In this state, a conductive material (silver palladium (AgPd)) is applied to the upper piezoelectric layer 140, thereby filling the through holes 168, 181L, and 181R with the conductive material. Next, as shown in FIG. 12C, the conductor layer 160 is formed using silver palladium (AgPd) on the upper surface of the upper piezoelectric layer 140 by a method such as screen printing with the mask M removed. To do. At this time, the individual electrode 141, the terminals 180L and 180R, and the dummy electrodes 198 and 199 are also formed of the same conductive material (silver palladium (AgPd)). Next, after the laminate 40 is fired, bumps BP are formed on the conductor layer 160 by a method such as screen printing, as shown in FIG. As described above, the bump BP is formed by a conductive adhesive such as silver paste. Next, after the bump BP is uncured and the bump BP formed on the conductor layer 160 is aligned with the COF 51, the COF 51 is turned into the bump BP as shown in FIG. 13B. The bump BP is cured by heating while being pressed. Thereby, the bump BP and the COF 51 are joined. In the process of pressing the COF 51 against the bump BP, the bump BP is crushed. As described above, in the present embodiment, the bump BP that has been crushed and deformed by the COF 51 is cured, whereby the conductor layer 165 in which the deformed bump BP is connected in a daisy chain is formed. As described above, since the DC junction is performed in the state where the conductor layer 160 is formed, a part of the conductor layer 165 overlaps with the conductor layer 160 as shown in FIG. Placed in.

  Also in the above-described DC bonding, heating is performed when the bump is cured, but heating is performed at a temperature lower than the temperature when firing the individual electrode 141 and the conductor layer 160. Therefore, the thermal stress remaining in the conductor layer 165 is negligibly small as compared with the thermal stress remaining in the individual electrode 141 and the conductor layer 160 when the individual electrode 141 and the conductor layer 160 are baked.

<About the effect of this embodiment>
In the above embodiment, the intermediate common electrode 241 and the terminal 180 </ b> L are electrically connected through the conductor layers 160 and 165 and the conductor in the through hole 168. The plurality of conductor layers 160 in which the through holes 168 are formed are arranged so as to be dispersed at a plurality of locations separated in the scanning direction. Thereby, a plurality of electrical paths (bypass wiring) from the terminal 180L to the intermediate common electrode 241 are provided. For this reason, even if one electrical path is disconnected due to, for example, a sufficient conductor not being filled in one of the through holes 168, electric charges are supplied to the intermediate common electrode 241 through the bypass wiring. And the reliability of electrical connection can be improved.

  In the above embodiment, the plurality of conductor layers 165 are formed in the vicinity of the end portion 140U of the upper piezoelectric layer 140, and are connected to the COF 51 by DC bonding. Since the vicinity of the end portion 140U of the upper piezoelectric layer 140 is a portion where the COF 51 is particularly easily bent, the bonding strength between the COF 51 and the piezoelectric body 40 can be increased by providing the conductor layer 165 at this portion.

  In the above embodiment, the seven conductor layers 160 are arranged in the scanning direction at intervals, and the conductor layer 165 is formed so as to connect the seven conductor layers 160. Since the conductor layer 165 is formed by bumps for bonding to the COF 51 by DC bonding, it does not contribute to warping deformation of the piezoelectric body 40. Therefore, compared with the case where the long conductor layer 160 is provided in one scanning direction (see FIG. 14), the residual stress can be suppressed to be small, and the warp deformation of the piezoelectric body 40 can be reduced.

  When the piezoelectric body 40 is bonded to the diaphragm 30 using an adhesive, the adhesive may protrude from the upper surface of the piezoelectric body 40 (that is, the upper surface of the upper piezoelectric layer 140). When the adhesive flows up to the region where the individual electrode 141 is formed, it can cause the function of the piezoelectric element to be impaired. In the present embodiment, since the conductor layers 160 and 165 are provided between the end portion 140U of the upper piezoelectric layer 140 and the individual electrode 141, the conductor layers 160 and 165 function as a barrier that blocks the adhesive. ing. The conductor layers 160 adjacent in the scanning direction can function as a barrier because the narrow portions 163 are arranged so as to face each other in the scanning direction. In the present embodiment, the conductor layer 165 connects the wide portions 162 of the conductor layers 160 adjacent in the scanning direction. In order to avoid the influence of the adhesive as much as possible, the end portions away from the end portion 140U in the conveying direction of the wide portion 162 are connected by the conductor layer 165. Therefore, the reliability of electrical connection between the conductor layer 165 and the conductor layer 160 can be improved.

  In addition, since the conductor layer 165 is formed higher than the conductor layer 160, the effect as a barrier is high. The position of the conductor layer 165 in the scanning direction is the same as the position of the narrow portion 143 of the individual electrode 141 in the scanning direction, and the narrow portion 143 is provided with bumps 191 that are bonded to the COF 51. Therefore, the conductor layer 165 can suppress the adhesive from reaching the bumps 191, so that the reliability of electrical bonding between the COF 51 and the bumps 191 can be improved. Since the bump 191 is disposed on the narrow portion 143, the diameter of the bump 191 cannot be made larger than the length of the narrow portion 143 in the transport direction. However, there is no such limitation on the size of the bump provided when forming the conductor layer 165, and thus the barrier function of the conductor layer 165 can be enhanced by making it larger than the diameter of the bump 191. In addition, since the cross-sectional area of the conductor layer 165 can be increased, the resistance value can be reduced.

  It should be noted that another conductor layer may be provided as a barrier for blocking the adhesive between the end portion 140U of the upper piezoelectric layer 140 and the individual electrode 141. For example, as shown in FIG. 14A, a conductor layer 190 extending in the scanning direction may be provided between the end 140U of the upper piezoelectric layer 140 and the conductor layers 160 and 165. For example, as shown in FIG. 14B, a conductor layer 191 may be provided so as to connect the wide portions 162 of the conductor layer 160 to each other. The conductor layers 190 and 191 can be formed of a conductive material such as silver palladium (AgPd) in the same manner as the conductor layer 160. In that case, the conductive layer 160 and the individual electrode 141 can be formed in the same process. Alternatively, the conductor layers 190 and 191 may be formed of a conductive adhesive such as a silver paste similarly to the conductor layer 160. In that case, the conductor layer 165 and the conductor layers 190 and 191 can be formed in the same step. Similarly to the conductor layer 165, the connection strength between the piezoelectric body 40 and the COF 51 can be further increased by bonding the conductor layers 190 and 191 to the COF 51 by DC bonding.

<Modification>
In the above embodiment, seven conductor layers 160 are provided, but the number of conductor layers 160 can be arbitrarily set. Further, the shape of the conductor layer 160 is not limited to the example of the above embodiment, and can be arbitrarily set. For example, the conductor layer 160 can have the same shape as the terminal 180L. Alternatively, as shown in FIG. 15, 1 extending in the scanning direction between the end portion 140 </ b> U of the upper piezoelectric layer 140 and the individual electrode 141 closest to the end portion 140 </ b> U of each individual electrode row 150. Two conductor layers 160S can also be formed. Similar to the above embodiment, the conductor 160S is formed at a position overlapping the extending portion 242 of the intermediate common electrode 241 in the stacking direction. An end of the conductor layer 160S in the scanning direction is connected to the terminal 180L. The conductor layer 160S can be formed of a conductive material such as silver palladium (AgPd) similarly to the individual electrode 141 and the terminal 180L. In this case, the conductor layer 160S can be formed in the same process as the individual electrode 141 and the terminal 180L. A plurality of through holes 168 are formed in the conductor layer 160S, and each through hole 168 is filled with a conductor. Similar to the above embodiment, the conductor filled in each through-hole 168 is electrically connected to the extending portion 242 of the intermediate common electrode 241.

  In the above embodiment, the piezoelectric body 40 has three piezoelectric layers, and electrodes are formed on the upper surface of each piezoelectric layer. However, the present teaching is not limited to such an aspect. The piezoelectric body may have two or more piezoelectric layers, and an electrode may be formed on the lower surface of each piezoelectric layer. In the above embodiment, the piezoelectric body has two common electrodes (an intermediate common electrode and a lower common electrode). However, the present teaching is not limited to such an aspect, and has only one common electrode. Also good. In addition, the shape of the common electrode (the shape of the extending portion and the protruding portion) can be arbitrarily set as necessary. In the above embodiment, the individual electrode 141 has the wide portion 142 and the narrow portion 143, but the shape of the individual electrode is not necessarily limited to such an aspect. For example, the width of the individual electrodes in the transport direction may be uniform in the scanning direction. The number of individual electrode rows, the number of individual electrodes per individual electrode row, the pitch of individual electrodes in the scanning direction, the magnitude of shift in the scanning direction of adjacent individual electrode rows, and the like are also examples of the above embodiment. It is not restricted to, It can set arbitrarily.

  In the above-described embodiment and modification, the present teaching is applied to the inkjet head 5 that prints an image or the like by ejecting ink onto a recording sheet. In the above-described embodiment, the ink jet head 5 is a so-called serial ink jet head, but the present teaching is not limited to this, and can be applied to a so-called line ink jet head. Further, the present teaching is not limited to an inkjet head that ejects ink. The present teaching can also be applied to a liquid ejecting apparatus used for various purposes other than printing of images and the like. For example, the present teaching can also be applied to a liquid ejection apparatus that ejects a conductive liquid onto a substrate to form a conductive pattern on the surface of the substrate.

5 Inkjet head 40 Piezoelectric body 140 Upper piezoelectric layer 141 Individual electrode 240 Intermediate piezoelectric layer 241 Intermediate common electrode 340 Lower piezoelectric layer 341 Lower common electrode

Claims (15)

A piezoelectric body in which a plurality of piezoelectric layers are stacked, the first end and the second end being separated in a first direction orthogonal to the stacking direction of the plurality of piezoelectric layers, and the stacking direction and the first direction orthogonal A piezoelectric body having a third end and a fourth end separated in a second direction;
A common electrode formed along a first surface which is a surface orthogonal to the stacking direction;
A bypass wiring formed along a second surface that is perpendicular to the stacking direction and whose position in the stacking direction is different from the position in the stacking direction of the first surface;
The second surface or a surface orthogonal to the stacking direction, the position in the stacking direction being formed along a third surface different from the position in the stacking direction of the first surface and the second surface. A plurality of individual electrodes,
The plurality of individual electrodes constitute a plurality of individual electrode rows arranged with a gap between the first end and the second end,
The plurality of individual electrode rows include a first individual electrode row, a second individual electrode row arranged in the first direction with the first individual electrode row, and the first individual electrode row includes: The first individual electrode row is located between the first end and the second individual electrode row in the first direction, and the second individual electrode row is located between the first individual electrode row and the second end in the first direction. Position to,
The plurality of individual electrodes constituting the first individual electrode row are arranged along the second direction,
The plurality of individual electrodes constituting the second individual electrode row are arranged along the second direction,
The common electrode is
A first extension portion extending in the first direction between the fourth end in the second direction and one of the individual electrodes closest to the fourth end in the second direction;
A second extending portion extending in the second direction from the first extending portion toward the third end;
A plurality of first projecting portions projecting in the one direction from the second extending portion toward the first end or the second end, each constituting the first individual electrode array in the stacking direction A plurality of first protrusions that at least partially overlap the individual electrodes;
A third extending portion located between the second extending portion and the second end in the first direction and extending in the second direction from the first extending portion toward the third end; ,
A plurality of second projecting portions projecting in the one direction from the third extending portion toward the first end or the second end, each constituting the second individual electrode array in the stacking direction A plurality of second protrusions that at least partially overlap the individual electrodes,
The bypass wiring extends in the first direction between the fourth end in the second direction and one of the individual electrodes closest to the fourth end in the second direction, and At least a portion overlaps the first extension in the stacking direction;
The piezoelectric body includes a first through hole extending in the stacking direction between the conductor layer and the first extension portion, and a stack between the conductor layer and the first extension portion. A second through hole extending in the direction,
The liquid discharge head, wherein the conductor layer and the first extending portion are electrically connected by a conductive material disposed in the first through hole and the second through hole. The second surface is the outermost surface of the piezoelectric body,
The bypass wiring is
A layer of the conductive material disposed on the second surface, the conductive material layer disposed around an opening of the first through hole so as to be electrically connected to the inside of the first through hole. A first layer,
The conductive material layer disposed on the second surface, the conductive material layer disposed around the opening of the second through hole so as to be electrically connected to the inside of the second through hole. A second layer,
The liquid ejection head according to claim 1, further comprising: the first film unit and a third layer disposed on the second film unit. The plurality of individual electrodes are formed on the second surface,
A dummy electrode of the individual electrode is disposed in the second direction between the conductor layer and one of the individual electrodes closest to the fourth end in the second direction on the second surface. The liquid discharge head according to claim 1 or 2. The plurality of individual electrodes are formed on the second surface,
The second surface is the outermost surface of the piezoelectric body,
The liquid discharge head further includes
A wiring member in electrical communication with the plurality of individual electrodes and the bypass wiring;
A plurality of conductive bonding members for bonding a part of the plurality of terminals provided on the wiring member and the terminals of the plurality of individual electrodes;
The liquid ejection head according to claim 1, wherein at least a part of the bypass wiring and the conductive bonding member are formed of the same material.   5. The liquid according to claim 4, wherein a length in the second direction of the bypass wiring is longer than a length in one second direction of the conductive bonding member that bonds one of the individual electrodes and one of the terminals. Discharge head. The bypass wiring includes a first portion and a second portion made of the same conductive material as the individual electrode, the first portion and the second portion being arranged apart from each other in the first direction, and the conductive portion. A third portion formed of the same conductive adhesive as the joining member, the third portion electrically connecting the first portion and the second portion;
6. The liquid ejection head according to claim 4, wherein the first through hole is formed in the first portion, and the second through hole is formed in the second portion.   The third portion is an end portion of the first portion in the second direction and close to the fourth end, and an end portion of the second portion in the second direction and the fourth end. The liquid discharge head according to claim 6, wherein the liquid discharge head is connected to an end portion close to. The first portion includes a first narrow portion, and a first wide portion having a length in the second direction larger than a length in the second direction of the first narrow portion,
The second portion includes a second narrow portion, and a second wide portion having a length in the second direction larger than a length in the second direction of the second narrow portion,
8. The liquid ejection head according to claim 6, wherein the first narrow portion and the second narrow portion are disposed so as to face each other in the first direction.   The liquid ejection head according to claim 8, wherein the third portion extends in the first direction so as to connect the first wide portion and the second wide portion. A conductor layer having a length in the first direction longer than the interval in the first direction between the first narrow portion and the second narrow portion, and is not connected to the bypass wiring. With a conductor layer,
The liquid ejection head according to claim 9, wherein the position of the conductor layer in the second direction is between the third end and the first portion in the second direction. A conductor layer having a length in the first direction that is longer than an interval in the first direction between the first narrow portion and the second narrow portion;
The conductor layer is an end portion in the second direction of the first portion and close to the third end, and an end portion in the second direction of the second portion and the third end. The liquid discharge head according to claim 9, wherein the liquid discharge head is connected to a near end.   The liquid discharge head according to claim 10, wherein the conductor layer is formed of the same conductive material as that of the individual electrode. The wiring member includes a plurality of wirings connected to the plurality of individual electrodes, and a wiring protective film covering the wirings,
13. The liquid ejection head according to claim 4, wherein the third portion is disposed at a position that does not overlap the wiring protective film of the wiring member in the stacking direction. The plurality of individual electrodes are formed on the second surface,
The bypass wiring extends in the first direction so that the position of the conductor layer in the second direction overlaps the position of the first individual electrode row and the second individual electrode row in the second direction. The liquid discharge head according to any one of claims 1 to 13. A piezoelectric body in which a plurality of piezoelectric layers are stacked, the first end and the second end being separated in a first direction orthogonal to the stacking direction of the plurality of piezoelectric layers, and the stacking direction and the first direction orthogonal A piezoelectric body having a third end and a fourth end separated in a second direction;
A common electrode formed along a first surface which is a surface orthogonal to the stacking direction;
A bypass wiring formed along a second surface that is perpendicular to the stacking direction and whose position in the stacking direction is different from the position in the stacking direction of the first surface;
The common electrode is
A first extending portion extending in the first direction;
A second extending portion extending in the second direction from the first extending portion toward the third end;
A plurality of first projecting portions projecting in the one direction from the second extending portion toward the first end or the second end;
A third extending portion located between the second extending portion and the second end in the first direction and extending in the second direction from the first extending portion toward the third end; ,
A plurality of second projecting portions projecting in the one direction from the third extending portion toward the first end or the second end;
The bypass wiring extends in the first direction, and at least a part of the bypass wiring overlaps the first extending portion in the stacking direction,
The piezoelectric body includes a first through hole extending in the stacking direction between the conductor layer and the first extension portion, and a stack between the conductor layer and the first extension portion. A second through hole extending in the direction,
The liquid discharge head, wherein the conductor layer and the first extending portion are electrically connected by a conductive material disposed in the first through hole and the second through hole.

Images