JP2007168319A - Droplet discharge head, droplet discharge device and process for manufacturing droplet discharge head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mount piezoelectric elements with high density by forming pressure chambers precisely. <P>SOLUTION: In a droplet head, a piezoelectric plate A is formed by laminating a plurality of piezoelectric plates 66 in which a first trench 68 is formed and a pressure chamber is formed in the first trench 68. Since formation of the first trench 68 is easier than boring, the pressure chamber can be formed precisely. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a droplet discharge head that discharges droplets, a droplet discharge apparatus that includes the droplet discharge head, and a droplet discharge head manufacturing method that manufactures the droplet discharge head.

  As a droplet discharge head that discharges droplets, an inkjet recording head that discharges ink and records an image on a recording medium is well known.

  Ink jet recording heads that use piezoelectric elements for ink ejection, especially in head configurations that use actuators that utilize the piezoelectric longitudinal or piezoelectric transverse effects of piezoelectric elements, in order to increase the deformation efficiency of the actuator, a part of the pressure chamber It is necessary to provide a portion with low rigidity. However, providing a low-rigidity portion in the pressure chamber is problematic because it reduces the efficiency of pressure generation.

  On the other hand, in order to achieve high resolution by printing with an ink jet recording head, it is necessary to narrow the nozzle pitch and arrange the nozzles in high density, for example, in a matrix, and accordingly, piezoelectric elements provided corresponding to each nozzle Is required to have a small and high-density structure.

  Therefore, a pressure chamber is formed inside the laminated piezoelectric element, and the nozzle plate and the supply path plate are arranged opposite to each other with the piezoelectric element sandwiched in the laminating direction, so that a low rigidity portion is not provided in the pressure chamber. In both cases, there has been proposed a head configuration that can improve the pressure generation efficiency and can increase the density of the nozzle arrangement as compared with a conventional Kaiser-type piezoelectric element (see, for example, Patent Document 1).

  However, in the above-described configuration, since the pressure chamber is formed by making a long hole in the stacking direction in the stacked piezoelectric element, the positive and negative electrodes are exposed in the pressure chamber. Therefore, it is necessary to completely seal this electrode portion, and further, processing such as a through hole and a groove is required in accordance with the electrode, which causes a manufacturing problem. In addition, it is necessary to provide an electrically inactive region between the piezoelectric elements provided corresponding to the respective nozzles, which becomes an obstacle in mounting the piezoelectric elements at a higher density. Further, when the piezoelectric element is compressed / expanded and deformed in the stacking direction, the deformation state of the end surface on the supply path plate side is not flat, and stress may be generated at the joint between the supply path plate and the piezoelectric element, leading to a failure. .

In addition, in order to improve the pressure generation efficiency, the pressure chamber is made more than the pressure chamber is deformed in one direction (piezoelectric element stacking direction) and pressure (discharge energy) is applied to the ink as in the above configuration. It is desirable to deform in multiple directions and apply pressure to the ink on many faces in the pressure chamber.
Japanese Patent Laid-Open No. 7-81055

  By the way, in an ink jet recording head in which nozzles are arranged with high density in order to realize high resolution, pressure chambers are also arranged with high density, and therefore it is necessary to form pressure chambers with high accuracy.

  However, in the configuration as in Patent Document 1, since the piezoelectric elements are stacked and thick in the stacking direction, it is difficult to process with high accuracy when forming a pressure chamber by opening a long hole in the stacking direction.

  In view of the above-described facts, the present invention provides a droplet discharge head capable of forming a pressure chamber with high accuracy, a droplet discharge apparatus including the droplet discharge head, and a droplet discharge head manufacturing method for manufacturing the droplet discharge head. The task is to do.

  The droplet discharge head according to claim 1 of the present invention is a droplet head in which a piezoelectric actuator pressurizes a pressure chamber to which a liquid is supplied and discharges the droplet, and the piezoelectric actuator includes a plurality of grooves formed with grooves. A piezoelectric plate is formed by laminating and bonding, and the pressure chamber is formed in the groove.

  In this configuration, the piezoelectric actuator pressurizes the pressure chamber to which the liquid is supplied to discharge the droplets.

  Here, the piezoelectric actuator according to claim 1 of the present invention is formed by laminating and joining a plurality of piezoelectric plates each having a groove, and a pressure chamber is formed in the groove. Since forming the groove is easier to process than forming the hole, according to the configuration of the first aspect, the pressure chamber can be formed with high accuracy.

  The droplet discharge head according to claim 2 of the present invention is a droplet head in which a piezoelectric actuator pressurizes a pressure chamber to which a liquid is supplied and discharges the droplet, and the piezoelectric actuator includes a plurality of through holes formed therein. The piezoelectric plate is formed by laminating and bonding, and the pressure chamber is formed in the through hole.

  In this configuration, the piezoelectric actuator pressurizes the pressure chamber to which the liquid is supplied to discharge the droplets.

  Here, the piezoelectric actuator according to claim 2 of the present invention is formed by stacking and joining a plurality of piezoelectric plates each having a through hole, and a pressure chamber is formed in the through hole. Since the piezoelectric plate in which the holes are formed is laminated and bonded more easily than the case in which the elongated holes are formed after the piezoelectric plate is laminated and bonded, the pressure chamber can be accurately formed. Can be formed.

  According to a third aspect of the present invention, there is provided a liquid droplet ejection apparatus comprising the liquid droplet ejection head according to the first or second aspect.

  According to a fourth aspect of the present invention, there is provided a liquid discharge head manufacturing method for manufacturing the liquid discharge head according to the first aspect, wherein a plurality of piezoelectric plates having grooves are laminated and bonded. And a bonding step of forming a cavity to be a pressure chamber in the groove.

  In this configuration, a plurality of piezoelectric plates in which grooves are formed are laminated and joined to form a cavity that becomes a pressure chamber in the groove. Since forming the groove is easier to process than forming the hole, the pressure chamber can be formed with high accuracy according to the configuration of claim 4.

  According to a fifth aspect of the present invention, there is provided the method for manufacturing a liquid ejection head according to the fourth aspect, wherein the joining step includes laminating and baking a plurality of piezoelectric plates on which the grooves are formed. To do.

  In this configuration, a plurality of piezoelectric plates in which grooves are formed are stacked, fired, and bonded. This eliminates the need for bonding using an adhesive or the like, and prevents an adhesive or the like from entering a supply path to which a liquid is supplied and blocking the supply path or the like.

  According to a sixth aspect of the present invention, in the method of manufacturing a liquid ejection head according to the fourth or fifth aspect, the piezoelectric plate bonded in the bonding step is perpendicular to the groove forming direction in which the grooves are formed. And a cutting step for cutting.

  A liquid discharge head manufacturing method according to a seventh aspect of the present invention is a liquid discharge head manufacturing method for manufacturing the liquid discharge head according to the second aspect, wherein a plurality of piezoelectric plates having through holes are laminated and bonded. And it has the joining process which forms the cavity used as a pressure chamber in the said through-hole.

  In this configuration, a plurality of piezoelectric plates formed with through holes are laminated and joined to form a cavity serving as a pressure chamber in the through hole. Compared to the case where the elongated holes are formed after the piezoelectric plates are laminated and bonded, it is easier to process by laminating and bonding the piezoelectric plates in which the holes are formed. Can be formed.

  According to an eighth aspect of the present invention, in the liquid ejection head manufacturing method according to any one of the fourth to seventh aspects, a peripheral groove is formed on a surface around the cavity formed in the joining step, and A groove forming step for forming the peripheral portion of the cavity into a cylindrical shape is provided.

  According to a ninth aspect of the present invention, in the method of manufacturing a liquid ejection head according to the eighth aspect, a substrate bonding step of bonding a wiring substrate for sending a drive signal to the electrode of the piezoelectric actuator to the piezoelectric actuator, and the substrate. And an electrode forming step of forming an electrode of the piezoelectric actuator after the joining step.

  According to a tenth aspect of the present invention, in the configuration of the ninth aspect, the electrode forming step further includes electrically connecting the electrode and the wiring board.

  According to an eleventh aspect of the present invention, in the liquid ejection head manufacturing method according to the ninth or tenth aspect of the present invention, the electrode forming step forms an electrode by sputtering or vapor deposition. .

  In the liquid discharge head manufacturing method according to a twelfth aspect of the present invention, in the configuration according to any one of the ninth to eleventh aspects, the electrode forming step is performed from the outer peripheral surface of the peripheral portion of the hollow cavity. Separation in which an electrode is formed over the inner peripheral surface of the cavity, the end face of the peripheral portion made into a cylindrical shape is polished, and the electrode is separated into the outer peripheral surface of the peripheral portion of the cavity and the inner peripheral surface of the cavity A process is provided.

  A liquid discharge head manufacturing method according to a thirteenth aspect of the present invention includes the protective film forming step of forming a protective film for protecting the electrode from the liquid in the configuration according to any one of the ninth to twelfth aspects. It is characterized by.

  According to a fourteenth aspect of the present invention, in the liquid ejection head manufacturing method according to the thirteenth aspect, the protective film is a low water permeable film.

  According to a fifteenth aspect of the present invention, in the liquid ejection head manufacturing method according to the thirteenth aspect, the protective film is an inorganic protective film containing any one of silicon oxide, silicon nitride, and silicon oxynitride. And

  A liquid discharge head manufacturing method according to a sixteenth aspect of the present invention is the method according to any one of the thirteenth to fifteenth aspects, wherein the liquid is supplied to the cavity serving as the pressure chamber in one of the piezoelectric actuator and the electric wiring board. A supply plate bonding step for bonding a supply plate in which a supply path for supply is formed, and a nozzle for bonding a nozzle plate formed with a nozzle for discharging the droplets to the other of the piezoelectric actuator and the electric wiring board And a plate joining step.

  Since the present invention has the above configuration, the pressure chamber can be formed with high accuracy.

  Hereinafter, an example of an embodiment according to a droplet discharge head, a droplet discharge device, and a droplet discharge head manufacturing method of the present invention will be described with reference to the drawings.

  First, an outline of an ink jet recording apparatus 100 as a droplet discharge apparatus will be described with reference to FIG. The recording medium will be described as recording paper P. In FIG. 1, the conveyance direction of the recording paper P in the inkjet recording apparatus 100 is represented by an arrow S as a sub-scanning direction, and the direction orthogonal to the conveyance direction is represented by an arrow M as a main scanning direction.

  As shown in FIG. 1, the ink jet recording apparatus 100 according to the present embodiment includes a carriage 112 on which black, yellow, magenta, and cyan ink jet recording units 130 (ink jet recording heads 10) are mounted. The carriage 112 has a pair of brackets 114 protruding from the upstream side in the conveyance direction of the recording paper P (only one bracket 114 is shown in the figure), and circular holes formed in the pair of brackets 114 respectively. The shaft 120 installed in the main scanning direction is inserted.

  A driving pulley (not shown) and a driven pulley (not shown) constituting the main scanning mechanism 116 are disposed on both ends in the main scanning direction with respect to the carriage 112. A part of a timing belt 122 that is wound around these driving pulleys and driven pulleys and travels in the main scanning direction is fixed to the carriage 112. Accordingly, when the timing belt 122 travels in the main scanning direction by the rotational driving of the driving pulley, the carriage 112 is reciprocated in the main scanning direction by the pair of brackets 114 being guided by the shaft 120.

  A paper feed tray 126 for storing recording paper P before image printing in a bundle is provided at the lower front side of the inkjet recording apparatus 100. Above the paper feed tray 126, a paper discharge tray 128 for discharging the recording paper P on which an image has been printed by the ink jet recording unit 130 for each color is provided. Also, below the carriage 112 and the shaft 120, there is a sub-scanning mechanism 118 composed of a transport roller and a discharge roller for transporting the recording paper P fed one by one from the paper feed tray 126 at a predetermined pitch in the sub-scanning direction. Is provided.

  In addition, the inkjet recording apparatus 100 is provided with a control panel 124 for performing various settings during printing, a maintenance station (not shown), and the like. The maintenance station includes a cap member, a suction pump, a dummy jet receiver, a cleaning mechanism, and the like, and performs maintenance operations such as a suction recovery operation, a dummy jet operation, and a cleaning operation.

  Each color ink jet recording unit 130 is configured by integrally forming the ink jet recording head 10 shown in FIGS. 2 and 3 and an ink tank (not shown) for supplying ink to the ink jet recording head 10. A plurality of nozzles 22 (see FIG. 3) formed on the lower surface (ink ejection surface) of the recording medium P are mounted on the carriage 112 so as to face the recording paper P. As a result, the ink jet recording head 10 selectively ejects ink droplets from the nozzles 22 on the recording paper P while moving in the main scanning direction by the main scanning mechanism 116, thereby image data for a predetermined band region. A part of the image based on is recorded.

  When one movement in the main scanning direction is completed, the recording paper P is conveyed by a predetermined pitch in the sub scanning direction by the sub scanning mechanism 118, and the ink jet recording head 10 (ink jet recording unit 130) is again moved in the main scanning direction ( A part of the image based on the image data is recorded in the next band area while moving in the opposite direction). By repeating such an operation a plurality of times, the recording paper P The entire image based on the image data is recorded in full color.

  Next, the ink jet recording head (droplet discharge head) 10 mounted on the ink jet recording apparatus 100 will be described.

  The inkjet recording head 10 of this embodiment shown in FIGS. 2 to 4 includes a nozzle plate 12, a printed wiring board 14, a piezoelectric element substrate (piezoelectric actuator) 16, a supply path plate 18, and an ink pool plate from the lower side of the figure. The members are laminated in the order of 20, and each member is joined to each other.

  As shown in FIG. 2, the nozzle plate 12 has a plurality of nozzles 22 each having a circular through hole, and these nozzles 22 are arranged in a matrix at predetermined intervals.

  In the printed wiring board 14, communication paths 24 each having a circular through hole having a diameter slightly larger than the nozzle diameter are formed at positions corresponding to the nozzles 22 of the nozzle plate 12 (FIGS. 4A and 4B). B)). An annular contact electrode 26 is formed on the upper surface of the printed wiring board 14 at a position corresponding to each communication path 24, and each contact electrode 26 is connected via a wiring pattern 28 formed on the upper surface of the substrate. The drive IC 30 mounted in the vicinity of the end of the upper surface of the substrate is electrically connected. The drive IC 30 receives a control signal (printing command) from the outside (head control unit) through a contact portion 31 formed on the printed wiring board 14, and a piezoelectric element described below based on the control signal. An electric signal (drive signal) is transmitted to each piezoelectric element 32 on the substrate 16 to drive each piezoelectric element 32 at a predetermined timing.

  Further, a common connection electrode 67 is formed in parallel with the annular contact electrode 26 at a position where the upper surface of the printed wiring board 14 is not provided with the communication passage 24. The common connection electrode 27 is connected to the GND potential via a wiring pattern 69 formed on the upper surface of the printed wiring board 14.

  As shown in FIG. 5, the piezoelectric element substrate 16 includes a plurality of piezoelectric elements 32 that are individually driven by the driving IC 30 and a common electrode connecting piezoelectric body 73. These piezoelectric elements 32 have a rectangular cylindrical shape, and a circular cavity R penetrating along the thickness direction of the piezoelectric element substrate 16 is formed therein. The inner diameter of the cavity R is slightly larger than the communication path 24 (see FIGS. 4A and 4B). The piezoelectric elements 32 are arranged in a matrix corresponding to the nozzles 22 and the communication paths 24, and the lower ends thereof are integrated with the thin base substrate portion 33.

  The common electrode connecting piezoelectric body 73 has substantially the same shape as the piezoelectric element 32, and is formed at a position corresponding to the common connecting electrode 67. The height of the common electrode connecting piezoelectric body 73 is configured to be lower than the height of the piezoelectric element 32 (at least by the thickness of electrodes 38 and 34 described later).

  As shown in FIGS. 4A and 4B, the positive electrode 34 is formed on the outer peripheral surfaces of the piezoelectric element 32 and the common electrode connecting piezoelectric body 73 so as to cover the entire outer peripheral surface. Each piezoelectric element 32 and the electrode 34 of the common electrode connecting piezoelectric body 73 are electrically connected to each other via a common electrode 36 formed on the upper surface of the base substrate portion 33. On the inner peripheral surfaces of the piezoelectric element 32 and the common electrode connecting piezoelectric member 73, a negative electrode 38 is formed so as to cover the entire inner peripheral surface. The electrodes 38 of each piezoelectric element 32 are electrically connected with their lower ends in contact with the respective contact electrodes 26 on the printed wiring board 14.

  A distal end surface electrode 73 </ b> C is formed on the distal end surface of the common electrode connecting piezoelectric body 73. Accordingly, in the common electrode connecting piezoelectric body 73, the electrode 38 and the front end surface electrode 73 </ b> C are connected to the electrode 34, and each piezoelectric element 32 starts from the cavity R portion provided in the common electrode connecting piezoelectric body 73. The common electrode 34 is drawn out and connected to the GND potential via the wiring pattern 69.

  Thus, in the cylindrical piezoelectric element 32, the positive electrode (electrode 38) is provided on the outer peripheral surface and the negative electrode (electrode 34) is provided on the inner peripheral surface, so that the polarization direction is the inner and outer directions of the piezoelectric element 32. Specifically, the piezoelectric element 32 is configured so as to be directed from the outside toward the inside. The positive and negative electrodes can be arranged oppositely inside and outside the piezoelectric element 32. The piezoelectric element 32 is configured as a so-called wall-type piezoelectric element by having a structure in which a side surface (outer surface) in the polarization direction is connected to a wall portion (base substrate portion 33). Thus, when an electrical signal from the driving IC 30 is applied to the piezoelectric element 32 disposed between the electrodes 34 and 38, the piezoelectric element 32 performs a predetermined deformation operation described later.

  In the supply path plate 18, supply paths 40 each having a circular through hole slightly smaller than the inner diameter of the piezoelectric element 32 are formed at positions corresponding to the piezoelectric elements 32 of the piezoelectric element substrate 16 (FIG. 4 ( A) and (B)). At a position corresponding to each piezoelectric element 32 on the lower surface of the supply path plate 18, there is a protruding part (thick part) 42 that protrudes in a circular shape having the same diameter as the outer diameter of the piezoelectric element 32 around the supply path 40. These protrusions 42 are provided, and the protrusions 42 are firmly joined to the piezoelectric elements 32. Further, the protruding portions 42 are connected to each other, and the connecting portions (around the protruding portions 42) are thinner than the supply path plate main body and the protruding portions 42. A low-rigidity damper portion 44 is formed by the connecting portions. Has been.

  When the supply path plate 18 is laminated on the piezoelectric element substrate 16, as shown in FIGS. 4A and 4B, a pressure chamber 46 is formed in the cavity R inside the square cylindrical piezoelectric element 32. In the pressure chamber 46, the upper wall surface 46 </ b> A is formed by the lower surface (movable inner wall surface) of the projecting portion 42, and the inner wall surface 46 </ b> B having a peripheral surface shape is the inner peripheral surface ( It is formed by the deformation part.

  As shown in FIG. 4A, the ink pool plate 20 has a cavity formed on the lower surface side, and an ink inlet (ink supply path) 48 communicating with the cavity is provided on the upper surface. Yes. When the ink pool plate 20 is stacked on the supply path plate 18, an ink pool 50 is formed between the ink path plate 18 and the supply path plate 18. Further, the damper portion 44 of the supply path plate 18 is a constituent part constituting a part of the inner wall of the ink pool 50, and ink is passed through the ink inlet 48 from the outside (ink tank) to the ink pool 50. Supplied and stored.

  The ink jet recording head 10 of the present embodiment has the above-described configuration. In the ink jet recording head 10, as described above, each part from the nozzle 22 to the ink pool 50 (nozzle 22, communication path 24, pressure chamber 46 ( The piezoelectric element 32), the supply path 40, and the ink pool 50) are arranged in layers by the respective constituent members.

  Next, the printing (ink ejection) operation and action by the above-described inkjet recording head 10 of the present embodiment will be described.

  In printing by the ink jet recording head 10, first, ink stored in the ink pool 50 is supplied to the pressure chamber 46 through the supply path 40, and further filled from the pressure chamber 46 to the nozzle 22 through the communication path 24.

  Here, when an electrical signal is not applied between the electrodes 34 and 38, the piezoelectric element 32 is maintained in a cylindrical shape as shown in FIG. Further, when an electrical signal is applied between the electrodes 34 and 38 by a printing command, the piezoelectric element 32 is charged and deformed so as to expand in a barrel shape when viewed in the axial cross section as shown in FIG. 6B. To do.

  In the piezoelectric element 32 of this embodiment, as shown in FIG. 6 (C), the piezoelectric longitudinal effect (d33) that applies an electric signal in the polarization direction and causes distortion in the direction parallel to the electric signal causes the inside and outside indicated by the arrow d33. The piezoelectric transverse effect (d31) that expands and deforms in the direction, adds an electric signal in the polarization direction, and generates distortion in the direction perpendicular thereto, compresses and deforms in the axial direction indicated by the arrow d31 (a), and moves to the arrow d31 ( It contracts and deforms in the side direction indicated by b). As described above, the cylindrical piezoelectric element 32 is deformed in three directions, ie, an inner and outer direction due to the piezoelectric longitudinal effect, an axial direction due to the piezoelectric lateral effect, and a side direction.

  Here, due to the compressive deformation in the axial direction due to the piezoelectric lateral effect of the piezoelectric element 32, the protrusion 42 of the supply path plate 18 joined to the upper end surface of the piezoelectric element 32, that is, the upper wall surface 46A of the pressure chamber 46 is on the nozzle 22 side. (Arrow A in FIG. 6B), the ink in the pressure chamber 46 is pressurized and compressed. Further, the expansion deformation in the inner and outer directions due to the piezoelectric longitudinal effect of the piezoelectric element 32 and the contraction deformation in the side direction due to the piezoelectric lateral effect are combined, and the inner peripheral surface (deformation portion) of the piezoelectric element 32, that is, the pressure chamber 46. The inner wall surface 46B bulges inward (arrow B in FIG. 6B), and pressurizes and compresses the ink in the pressure chamber 46. The ink in the pressure chamber 46 pressurized by the deformation of the pressure chamber 46 in the two directions by these two deformation operations is ejected from the nozzle 22 as an ink droplet through the communication path 24.

  Subsequently, when the application of the electric signal between the electrodes 34 and 38 is stopped and the electric charge accumulated in the piezoelectric element 32 is discharged, the piezoelectric element 32 is shown in FIG. 6A from the state of FIG. Return to the original cylindrical shape. Along with this, due to the return force of the meniscus formed in the nozzle 22, the ejected ink is replenished from the ink pool 50 into the pressure chamber 46 through the supply path 40.

  By repeating this ink ejection operation, ink droplets are continuously ejected from the nozzles 22 of the inkjet recording head 10 and printed on paper or the like.

  As described above, in the inkjet recording head 10 of the present embodiment, the ink supplied from the ink pool 50 to the pressure chamber 46 via the supply path 40 is ejected from the nozzle 22 as ink droplets. The pressure chamber 46 is deformed by deformation, and pressure is applied to the ink in the pressure chamber 46. This piezoelectric element 32 deforms the pressure chamber 46 in two directions by deformation of the piezoelectric longitudinal effect and the piezoelectric transverse effect. For example, the pressure generation efficiency is improved as compared with the case where the pressure chamber is deformed by deformation of only the piezoelectric longitudinal effect or only the piezoelectric lateral effect.

  In this embodiment, the inner peripheral surface, which is a deformed portion of the piezoelectric element 32 that forms the inner wall surface 46B of the pressure chamber 46, directly pressurizes the ink in the pressure chamber 46, so that the pressure applied to the ink is reduced. The loss is reduced, and the pressure generated by the deformation of the piezoelectric element 32 is efficiently transmitted to the ink.

  In the present embodiment, the upper wall surface 46A of the pressure chamber 46 moves in accordance with the deformation of the piezoelectric element 32, and the ink in the pressure chamber 46 is pressurized / depressurized in the ejection direction (nozzle 22 side). Thereby, the pressure chamber 46 can be deformed in the ink discharge direction, and the pressure generation efficiency can be improved. Further, the upper wall surface 46A (movable inner wall surface) of the pressure chamber 46 having the movable structure is formed by the supply path plate 18 (projecting portion 42), so that a dedicated inner wall surface is formed to form such a movable inner wall surface. Compared with the case where a plate or the like is provided, the inkjet recording head 10 can be configured in a small size.

  In the present embodiment, the piezoelectric element 32 is driven at a high speed by the above-described ink ejection operation. When the piezoelectric element 32 and the upper wall surface 46A (the protruding portion 42) of the pressure chamber 46 vibrate due to the high speed driving, The vibration is attenuated by the damper portion 44 that connects the protruding portions 42 and has a lower rigidity than the supply plate main body. Thereby, the influence (crosstalk) of the driving operation between the adjacent piezoelectric elements 32 can be reduced.

  Further, since the damper portion 44 is a constituent part that constitutes a part of the inner wall of the ink pool 50, the pressure generated in the pressure chamber 46 for ejecting ink droplets is absorbed by the damper portion 44. Thereby, the pressure generated in the specific pressure chamber 46 when ink droplets are ejected is transmitted from the supply path 40 to the ink pool 50, and the adverse effect on the pressure generation in the adjacent pressure chamber 46 can be improved. Accordingly, the ink ejection performance is stabilized.

  Further, in the ink jet recording apparatus 100 of this embodiment, the power consumption can be reduced by providing the ink jet recording head 10 described above.

  As shown in FIG. 7A, the plurality of piezoelectric elements 62 provided in the piezoelectric element substrate 60 form a cavity R having a square cross section penetrating along the thickness direction of the piezoelectric element substrate 16 therein. May be. When an electric signal is applied between the electrodes 34 and 38, the piezoelectric element 62 also expands and deforms in the inner and outer directions indicated by the arrow d33 due to the piezoelectric longitudinal effect (d33), as shown in FIG. Further, the piezoelectric lateral effect (d31) causes compression deformation in the axial direction indicated by the arrow d31 (a), contraction deformation in the side direction indicated by the arrow d31 (b), and a sectional view in the axial direction is shown in FIG. It is deformed in the directions of arrows A and B shown in (B).

  Therefore, even in the case of the piezoelectric element 62 having such a cavity R having a quadrangular cross section, the deformations of the piezoelectric longitudinal effect and the piezoelectric transverse effect are combined, and the pressure generation efficiency can be improved.

  Here, a method for manufacturing the inkjet recording head 10 will be described.

  The method of manufacturing the inkjet recording head 10 of the present embodiment includes a step of manufacturing a piezoelectric plate A in which cavities R are formed in a matrix, a step of manufacturing a piezoelectric element substrate 16 before electrode formation from the piezoelectric plate A, and electrodes. The step of joining the piezoelectric element substrate 16 and the printed wiring board 14 before formation to form electrodes, the protective film forming step for forming a protective film for protecting the formed electrodes from liquid, the piezoelectric element substrate 16 and the printed wiring board 14 And laminating and joining the plates.

  The process of manufacturing the piezoelectric plate A in which the cavities R are formed in a matrix form includes a first groove forming process, a joining process, and a cutting process. In the first groove forming step, as shown in FIG. 8, a plurality of first grooves 68 are formed in a rectangular piezoelectric plate (plate-shaped piezoelectric body) 66 so as to be parallel to the side surface 66A. To do. The plurality of first grooves have a rectangular shape cut to a predetermined depth, and are formed so as to be parallel to each other at equal intervals. The first groove 68 is formed by scraping and processing the groove portion using a cutter or the like. A part of the cavity in the groove finally becomes a space of the pressure chamber 46 of the inkjet recording head 10.

  Next, in the joining step, as shown in FIG. 9, a plurality of piezoelectric plates 66 in which the first grooves 68 are formed in the first groove forming step are sandwiched between the piezoelectric plates 70 in which no grooves are formed. Then, the piezoelectric plates 66 and 70 are laminated. The piezoelectric plate 66 is laminated with the surface on which the grooves are formed facing in one direction (upward in FIG. 9). The laminated piezoelectric plates 66 and 70 are integrally fired to join the piezoelectric plates 66 and 70 together. Since the piezoelectric plates 66 and 70 are bonded after being laminated, it is not necessary to use an adhesive or the like.

  Alternatively, the first groove 68 may be formed in the piezoelectric plate 66 after firing, and the piezoelectric plate 66 and the fired piezoelectric plate 70 may be laminated and bonded with an adhesive or the like.

  Next, in the cutting step, the piezoelectric plates 66 and 70 bonded in the bonding step are cut in a direction orthogonal to the groove forming direction in which the first groove 68 is formed so as to have a predetermined thickness.

  Thus, the piezoelectric plate A in which the cavities R are formed in a matrix is manufactured through the first groove forming step, the joining step, and the cutting step.

  As shown in FIG. 10, the first groove 68 may be a groove having a semicircular cross section. In the first groove forming step in this case, semicircular first grooves 68 are formed on both surfaces of the three piezoelectric plates 66, and the semicircular first grooves 68 are formed on one surface of the two piezoelectric plates 66. Form.

  In the bonding step, the piezoelectric plate 66 having the first groove 68 formed on both sides is arranged in the center, and the piezoelectric plate 66 having the first groove 68 formed on one side is sandwiched between both sides thereof. Further, on both sides, piezoelectric plates 70 having no grooves are disposed, and the piezoelectric plates 66 and 70 are laminated. The piezoelectric plates 66 are stacked such that the first grooves 68 face each other and the first grooves 68 are joined together to form a cavity R having a circular cross section. The laminated piezoelectric plates 66 and 70 are integrally fired to join the piezoelectric plates 66 and 70 together.

  In the cutting step, the piezoelectric plate A is manufactured which is cut to a predetermined thickness and in which a cavity R having a circular cross section is formed in a matrix shape.

  Next, another example of the process for manufacturing the piezoelectric plate A in which the cavities R are formed in a matrix will be described.

  In this example, as shown in FIG. 11, through holes 74 having a rectangular cross section are formed in a matrix in a rectangular piezoelectric plate 72 that is thinner than the piezoelectric plate A. A plurality of piezoelectric plates 72 (three in the present embodiment) in which the through-holes 74 are formed are stacked and joined to manufacture the piezoelectric plate A. As shown in FIG. 12, the through hole formed in the piezoelectric plate 72 may be a through hole 76 having a circular cross section.

  The through holes 74 and 76 are formed by sandblasting, water jet processing, ultrasonic processing, or the like. The piezoelectric plate 72 may be fired after the through holes 74 and 76 are formed by punching before firing. The piezoelectric plate 72 may be joined by a method of laminating the piezoelectric plates 72 before firing and firing them together, or a method of bonding and joining the piezoelectric plates 72 after firing.

Next, a process of manufacturing the piezoelectric element substrate 16 before electrode formation from the piezoelectric plate A is performed.
In this step, first, a portion (K) where the common electrode connecting piezoelectric body 73 on the piezoelectric plate A shown in FIG. 13A is arranged is removed on a straight line by a predetermined depth (FIG. 13B). )reference). The removal here can be performed by dicing or the like.

  Next, a peripheral groove forming step for forming peripheral grooves around the plurality of cavities R formed in the piezoelectric plate A is performed. In the peripheral groove forming step, first, as shown in FIG. 13C, a plurality of second grooves 78 parallel to the K portion where the common electrode connecting piezoelectric body 73 is arranged are formed in the portion where the piezoelectric element 32 is arranged. To do. The plurality of second grooves 78 have a rectangular shape cut to a predetermined depth, and are formed to be parallel to each other at equal intervals.

  Then, as shown in FIG. 13D, a plurality of third grooves 80 orthogonal to the second grooves 78 are formed and separated into the piezoelectric element 32 and the common electrode connecting piezoelectric body 73. The second groove 78 and the third groove 80 can be formed by wire processing, dicing processing or the like. In this way, by forming the second groove 78 and the third groove 80 that are orthogonal to each other, a peripheral groove is formed around the cavity R, and the peripheral portion of the cavity R is formed into a square cylinder, and the piezoelectric element 32 and the common electrode A connecting piezoelectric body 73 is formed.

  The order of performing the step of removing the portion where the common electrode connecting piezoelectric body 73 is disposed, the step of forming the second groove 78, and the step of forming the third groove 80 can be performed in any order. Further, the second groove 78 and the third groove 80 may be formed at the same time by using blasting such as sand blasting or water jet.

  Further, as shown in FIG. 14, the piezoelectric element substrate before electrode formation is manufactured through the same process in the piezoelectric plate A in which a cavity having a square cross section is formed. In this case, the piezoelectric element substrate 60 shown in FIG. 7A is manufactured.

  Next, the process of joining the piezoelectric element board | substrate 16 and the printed wiring board 14, and forming an electrode is performed. In this step, the printed wiring board 14 is bonded to the back surface side (side where the piezoelectric element 32 is not formed) of the base substrate portion 33 of the piezoelectric element substrate 16 before electrode formation. A communication path 24 is formed in the printed wiring board 14 at a position corresponding to the cavity of the piezoelectric element 32. The communication path 24 has a smaller diameter than the inner diameter of the cavity.

  As shown in FIG. 15 (A), the printed circuit board 14 and the piezoelectric element substrate 16 before electrode formation are joined with the base substrate portion 33 side of the piezoelectric element substrate 16 and the wiring surface of the printed circuit board 14 facing each other. Bonding is performed so that the contact electrode 26 on the upper surface of the printed wiring board 14 is exposed to the cavity R of the piezoelectric element 32 and the common connection electrode 67 is exposed to the cavity R of the common electrode connecting piezoelectric body 73. .

  Next, as shown in FIG. 15B, an electrode film D is formed on the entire surface on the piezoelectric element substrate 16 side and on the inner wall of the communication path 24 of the printed wiring board 14. The electrode film D can be formed by Cu deposition, sputtering, or the like. As a result, the electrode film D, the contact electrode 26 of the printed wiring board 14, and the common connection electrode 67 are also connected.

  Then, as shown in FIG. 15C, the electrode film D formed on the tip surface 32C of the piezoelectric element 32 is removed. The removal of the electrode film D can be performed by one-side polishing such as CMP. Thus, the electrode film D is separated into an electrode 38 formed on the inner wall 32A of the piezoelectric element 32 and an electrode 34 formed on the outer wall 32B of the piezoelectric element 32.

  Next, a protective film forming step for forming a protective film for protecting the contact electrode 26 and the electrode 38 from ink (liquid) is performed.

  The surface of the piezoelectric element substrate 16 is filled with a protective film resin, and a protective film 88 is formed on the surface of the electrode 38 including the contact electrode 26. The electrode 38 and the contact electrode 26 which are portions that come into contact with ink may be covered, but the protective film 88 may be formed on all electrode films.

  As the protective film, a low water-permeable film can be used. Specifically, an inorganic protective film containing any of silicon oxide, silicon nitride, and silicon oxynitride can be used. In FIG. 16, a black portion indicates an electrode film including the electrode 38 and the contact electrode 26, and a white portion indicates a protective film.

  Next, as shown in FIG. 4, the nozzle plate 12 is bonded to the lower side of the printed wiring board 14, and the supply path plate 18 is bonded to the upper side of the piezoelectric element substrate 16. At this time, the nozzle 22 and the communication path 24 are communicated with each other, and the positioning is performed so that the cavity R of the piezoelectric element 32 and the supply path 40 communicate with each other.

  Then, the ink pool plate 20 is joined to the upper part of the supply path plate 18 to manufacture the ink jet recording head 10.

  According to the above manufacturing method, the piezoelectric element substrate 16 is formed by laminating and bonding a plurality of piezoelectric plates on which the first grooves 68 are formed, and the pressure chambers 46 are formed in the first grooves 68. Since the groove is easier to process than the hole, the pressure chamber 46 can be formed with high accuracy.

  Moreover, the electrode 38 and the electrode 34 can be easily formed by forming the electrode film D and then removing the electrode film D from the tip end surface 32C of the piezoelectric element 32. Further, the contact electrode 26, the common connection electrode 67, and the electrode film can be connected in the electrode film forming step.

  Further, since the common electrode connecting piezoelectric body 73 is made lower than the piezoelectric element 32, when the electrode film D on the tip end surface 32C portion of the piezoelectric element 32 is removed, the tip end face 73A of the common electrode connecting piezoelectric body 73 is removed. The electrode film is not removed by polishing, and the common electrode can be easily pulled out to the printed wiring board 14 side through driving.

  In addition, in the case of such a square cylindrical shape, when forming a plurality of piezoelectric elements on a single substrate using etching or the like, it is easier to form individual piezoelectric elements than in a cylindrical shape, And it can arrange | position with a narrower space | interval. As a result, when a plurality of piezoelectric elements are arranged in a matrix, the rectangular cylindrical piezoelectric elements can be arranged at a higher density without creating wasted space than the cylindrical ones. Can be made dense.

  Further, in this embodiment, each part (nozzle 22, communication path 24, pressure chamber 46 (piezoelectric element 32), supply path 40, and ink pool 50) provided in the inkjet recording head 10 is arranged in different layers. In addition, the ink jet recording head 10 can be manufactured by forming each of these parts into a plurality of constituent members and stacking the constituent members. Thereby, the manufacturability of the inkjet recording head 10 is improved.

  In the above embodiment, an ink jet recording apparatus that records an image by ejecting ink is described as a liquid droplet ejecting apparatus that ejects liquid droplets, and ink is ejected as a liquid droplet ejecting head that ejects liquid droplets. The ink jet recording head for recording an image has been described. However, the droplet discharge device and the droplet discharge head according to the present invention are not limited to those that record an image on a recording sheet, and the liquid to be discharged is not limited to ink.

  For example, it is used industrially, such as a device that creates a color filter for display by discharging ink onto a polymer film or glass, or a device that forms bumps for component mounting by discharging solder in a welded state onto a substrate. The present invention can be applied to a droplet discharge device and a droplet discharge head in general used in the droplet discharge device.

  The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made without departing from the gist of the present invention.

FIG. 1 is a perspective view showing an appearance of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is an exploded perspective view showing an exploded state of the ink jet recording head according to the present embodiment. FIG. 3 is a perspective view showing an appearance of the ink jet recording head according to the present embodiment. 4A and 4B are cross-sectional views of the ink jet recording head according to the present embodiment. FIG. 4A is a cross-sectional view taken along the line 4A-4A in FIG. 3, and FIG. FIG. 5 is a perspective view showing the appearance of the piezoelectric element substrate according to the present embodiment. 6A is a cross-sectional view showing an undeformed state of the piezoelectric element and the pressure chamber according to the present embodiment, FIG. 6B is a cross-sectional view showing the deformed state, and FIG. 6C is a view of the piezoelectric element. It is an expansion perspective view which shows a deformation | transformation direction. FIG. 7 shows a modification of the piezoelectric element substrate according to the present embodiment, (A) is a perspective view showing the appearance of the piezoelectric element substrate according to the modification, and (B) is an enlarged view showing the deformation direction of the piezoelectric element. It is a perspective view. FIG. 8 is a view showing a first groove forming step according to the present embodiment. FIG. 9 is a diagram illustrating a joining process and a cutting process according to the present embodiment. FIG. 10 is a diagram showing a joining step and a cutting step when a circular cavity is formed in the piezoelectric plate according to the present embodiment. FIG. 11 is a diagram showing another example of a process for manufacturing a piezoelectric plate in which a cavity having a quadrangular cross section is formed according to the present embodiment. FIG. 12 is a diagram showing another example of a process for manufacturing a piezoelectric plate in which a cavity having a circular cross section is formed according to the present embodiment. FIG. 13 is a view showing a peripheral groove forming step for forming a peripheral groove around a cavity having a circular cross section formed in the piezoelectric plate according to the present embodiment. FIG. 14 is a diagram showing a peripheral groove forming step of forming a peripheral groove around a cavity having a quadrangular cross section formed in the piezoelectric plate according to the present embodiment. FIG. 15 is a diagram illustrating an electrode forming process according to the present embodiment. FIG. 16 is a diagram illustrating a protective film forming process according to the present embodiment.

Explanation of symbols

10 Inkjet recording head 12 Nozzle plate 14 Printed wiring board (wiring board)
16 Piezoelectric element substrate (piezoelectric actuator)
18 Supply path plate 34 Electrode 36 Common electrode 38 Electrode 46 Pressure chamber 66 Piezoelectric plate 68 First groove (groove)
70 Piezoelectric plate 72 Piezoelectric plate 74 Through hole 76 Through hole 78 Second groove (peripheral groove)
80 Third groove (peripheral groove)
88 Protective film 100 Inkjet recording apparatus R cavity

Claims (16)

In a droplet head in which a piezoelectric actuator pressurizes a pressure chamber to which a liquid is supplied and ejects a droplet,
The piezoelectric actuator is formed by laminating and bonding a plurality of piezoelectric plates each having a groove, and the pressure chamber is formed in the groove. In a droplet head in which a piezoelectric actuator pressurizes a pressure chamber to which a liquid is supplied and ejects a droplet,
The piezoelectric actuator is formed by laminating and joining a plurality of piezoelectric plates each having a through hole, and the pressure chamber is formed in the through hole.   A droplet discharge apparatus comprising the droplet discharge head according to claim 1. A liquid discharge head manufacturing method for manufacturing the liquid discharge head according to claim 1,
A method of manufacturing a liquid discharge head, comprising: a step of laminating and bonding a plurality of piezoelectric plates having grooves formed therein to form a cavity serving as a pressure chamber in the groove.   5. The method of manufacturing a droplet discharge head according to claim 4, wherein in the joining step, a plurality of piezoelectric plates in which the grooves are formed are stacked and fired to join.   6. The droplet discharge according to claim 4, further comprising a cutting step of cutting the piezoelectric plate bonded in the bonding step in a direction perpendicular to a groove forming direction in which the grooves are formed. Head manufacturing method. A liquid discharge head manufacturing method for manufacturing the liquid discharge head according to claim 2,
A method of manufacturing a droplet discharge head, comprising: a joining step of laminating and joining a plurality of piezoelectric plates formed with through holes to form a cavity serving as a pressure chamber in the through hole.   8. A groove forming step of forming a peripheral groove on a surface around a cavity formed in the joining step so that a peripheral portion of the cavity is formed into a cylindrical shape. 2. A method for producing a droplet discharge head according to 1. A substrate bonding step of bonding a wiring substrate for sending a drive signal to the electrode of the piezoelectric actuator to the piezoelectric actuator;
An electrode forming step of forming electrodes of the piezoelectric actuator after the substrate bonding step;
The method of manufacturing a droplet discharge head according to claim 8, comprising:   The method of manufacturing a droplet discharge head according to claim 9, wherein the electrode forming step further includes electrically connecting the electrode and the wiring board.   The method of manufacturing a droplet discharge head according to claim 9, wherein the electrode forming step forms an electrode by sputtering or vapor deposition. In the electrode forming step, an electrode is formed from the outer peripheral surface of the peripheral portion of the hollow cavity to the inner peripheral surface of the hollow,
10. A separation step of polishing an end face of a peripheral portion made into a cylindrical shape and separating the electrode into an outer peripheral surface of the peripheral portion of the cavity and an inner peripheral surface of the cavity. 12. The method for manufacturing a droplet discharge head according to any one of 11 above.   The method of manufacturing a droplet discharge head according to claim 9, further comprising a protective film forming step of forming a protective film that protects the electrode from the liquid.   The method of manufacturing a droplet discharge head according to claim 13, wherein the protective film is a low water permeable film.   14. The method of manufacturing a droplet discharge head according to claim 13, wherein the protective film is an inorganic protective film containing any one of silicon oxide, silicon nitride, and silicon oxynitride. A supply plate joining step of joining a supply plate in which a supply path for supplying a liquid to the cavity serving as the pressure chamber is formed on one of the piezoelectric actuator and the electric wiring board;
A nozzle plate joining step for joining a nozzle plate on which nozzles for discharging the droplets are formed on the other of the piezoelectric actuator and the electrical wiring board;
The method of manufacturing a droplet discharge head according to claim 13, comprising:

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