JP4924339B2 - Cavity unit for droplet discharge head - Google Patents

Description

  The present invention relates to a cavity unit of a droplet discharge head that discharges droplets.

  In general, a droplet discharge device, such as an inkjet printer device, includes a droplet discharge head that discharges a droplet from a nozzle hole. The droplet discharge head uses a liquid flow to a nozzle hole that discharges a droplet. A path has a cavity unit formed inside (see Patent Document 1). As disclosed in Patent Document 1, the cavity unit has a configuration in which a plurality of plates each having a through hole serving as a liquid flow path are stacked, and the through hole formed in each plate A liquid flow path is formed by communicating with each other, and liquid from a liquid supply source such as a liquid tank is supplied to the nozzle through the liquid flow path.

  A plurality of pressure chambers arranged in a row are arranged in the middle of the liquid flow path, and a long common liquid chamber is provided on the upstream side of the pressure chamber in the row direction of these pressure chambers. The nozzle holes arranged in rows corresponding to the pressure chambers are located at the downstream end of the liquid flow path. Then, when the actuator stacked in the cavity unit is selectively driven, a discharge pressure is applied to the liquid filled in the corresponding pressure chamber and the liquid is discharged from the nozzle hole to the outside, and from the common liquid chamber to the pressure chamber. The liquid is replenished by negative pressure.

At this time, the discharge pressure acting on the liquid in the selected one pressure chamber includes not only the forward component propagating to the nozzle holes but also the backward component propagating to the common liquid chamber. This backward component may cause so-called crosstalk in which the pressure reaches the other pressure chamber through the common liquid chamber. In this way, if the pressure propagates to an undesired pressure chamber, the liquid in the pressure chamber may be pumped to cause droplet discharge from an undesired nozzle hole, which is not preferable. Therefore, as disclosed in Patent Document 1, the plate (damper plate) stacked in the common liquid chamber is positioned on the side opposite to the surface facing the common liquid chamber at a position corresponding to the common liquid chamber. The surface is recessed to form a thin damper wall, and the pressure fluctuation in the common liquid chamber due to the pressure flowing back from the pressure chamber is alleviated by this damper wall.
Japanese Patent Laid-Open No. 2004-25636 (refer to FIG. 5 in particular)

  By the way, as the thickness of the damper wall is smaller (thin), the effect of relieving the pressure fluctuation can be enhanced, and in recent years, it is demanded to form the damper wall with a thickness of about several tens of microns. . However, in the ingot of the metal material on which the damper plate is formed, there is a trace amount of contaminants including additives injected at the time of manufacture, and as the damper wall becomes thinner, the thickness dimension of the damper wall However, when the particle size of such a contaminant is about the same, there may be a case where a partial chipping or crack, or a defect or a through hole is formed in the damper wall due to the falling off of the contaminant in the damper wall. When such a deficit or through hole is formed, the common liquid chamber and the concave space (damper space) located on the opposite side of the damper wall communicate with each other, and the damper space is filled with liquid. The damper wall may not be able to fully function to relieve pressure fluctuation in the common liquid chamber.

  Such a damper wall can be formed by wet etching. Specifically, a thin damper wall can be formed by half-etching the area of the damper plate masked in areas other than the area corresponding to the damper wall with an etching solution so that the area is concave in a sectional view. When such wet etching is employed, the flow rate of the etching solution increases at the peripheral portion of the concave portion, and this portion tends to be etched deeper than the central portion. Accordingly, when the central portion of the damper wall is etched to have a desired thickness dimension, the peripheral edge portion is etched deeper than the desired dimension. Therefore, when the contaminants fall off at this portion, There is a greater possibility that cracks, defects and through holes will be formed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cavity unit for a droplet discharge head that solves the above-described problems associated with thinning of a damper wall.

The present invention has been made in view of the above-described circumstances, and a cavity plate for a droplet discharge head according to the present invention includes a plurality of nozzles arranged in parallel through a plurality of pressure chambers arranged in the middle. A cavity unit for a droplet discharge head, which has a liquid flow path leading to a hole and is laminated with an actuator for applying pressure to the liquid in the pressure chamber so that the liquid is discharged from the nozzle hole. A common liquid chamber plate in which a common liquid chamber hole that forms a common liquid chamber that guides liquid from a source to the plurality of pressure chambers is formed in a long hole shape along the parallel arrangement direction of the pressure chambers, and the common liquid The wall portion laminated and bonded to the chamber plate, the surface opposite to the surface facing the common liquid chamber plate is recessed and a part of the wall is left on the common liquid chamber side is the pressure in the common liquid chamber Damper press that forms a damper wall to mitigate fluctuations And a preparative, the damper wall, the when viewed along the stacking direction of each plate, larger than the outline shape of the contour shape is the common liquid chamber hole, and thickness than the central portion to the peripheral portion and small thin portion is extended with the the common liquid chamber plate and the damper plate, the adhesive in the state in which the thin portion is positioned outwardly of said common liquid chamber hole when viewed along the stacking direction Furthermore, the thin-walled portion has the thinnest portion with the smallest thickness dimension in the middle of the cross section perpendicular to the extending direction of the thin-walled portion, and the thinnest portion is along the stacking direction. When viewed, it is located outside the common liquid chamber hole .

With this configuration, the thin wall portion formed on the periphery of the damper wall of the damper plate is located outside the common liquid chamber hole of the common liquid chamber plate and is located below the common liquid chamber plate. Since the surface is laminated and adhered, even if a defect or a through-hole is formed in the thin wall portion due to dropping off of contaminants, it is possible to prevent the common liquid chamber and the damper space from communicating with each other. In addition, by adopting such a configuration, the thinnest part where a defect or a through hole is most likely to be formed due to the removal of contaminants is located outside the common liquid chamber. The communication between the common liquid chamber and the damper space due to the formation can be effectively prevented.

  In addition, the damper wall may be formed by half-etching the region of the damper plate masked except for the region corresponding thereto with an etching solution. By adopting such a configuration, a thin wall portion is easily formed on the periphery of the damper wall by the etching solution. Therefore, by laminating and bonding the common liquid chamber plate and the damper plate as described above, the through hole is formed in the thin wall portion. Even if formed, it is possible to prevent the common liquid chamber and the damper space from communicating with each other.

  According to the cavity unit for a droplet discharge head according to the present invention, as the damper wall of the damper plate is thinned, contaminants in the material fall off from the damper wall, and a defect or a through hole is formed in the damper wall. Even in this case, it is possible to prevent the common liquid chamber and the damper space from communicating with each other.

  Hereinafter, a cavity unit of a droplet discharge head according to an embodiment of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a carriage on which a droplet discharge head including a cavity unit according to this embodiment is mounted, and is applied to an inkjet head that discharges ink of an inkjet printer as a droplet discharge head. The ink jet printer of the present invention can be applied not only as a single printer device but also as a printer of a multi-function device (MFD) having a copy function, a scanner function, a facsimile function, and the like. It is.

  An ink jet printer (not shown) is configured such that a carriage 1 on which an ink jet head is mounted is mounted across two guide shafts, and can be reciprocated (scanned) in the left-right direction in FIG. The ink jet head reciprocates in the scanning direction together with the carriage 1 and from a nozzle hole 28a (see FIG. 2) provided on the lower surface (lower side in FIG. 1) of FIG. Ink droplets are ejected onto a recording sheet transported downward (paper feeding direction intersecting the scanning direction, the back side of the paper surface in FIG. 1). As a result, desired characters and images are recorded on the recording paper P.

  As shown in FIG. 1, the carriage 1 includes, for example, a liquid tank 3 that supplies inks (liquids) of each color such as cyan, magenta, yellow, and black independently to a cavity unit 10 described later, and the liquid A holder case 4 that accommodates and holds the tank 3 and an inkjet head 6 that is attached to a lower portion of the holder case via a support frame 5 are provided.

  Further, the inkjet head 6 has a plate-type piezoelectric unit 11 laminated and bonded to the upper surface of the cavity unit 10 having a plurality of plates laminated and bonded and having a liquid flow path 10a (see FIG. 2) inside. A wiring unit (chip on film) 12 used for electrical connection with an external device is further joined to the upper surface of the piezoelectric unit 11, and a driver IC 51, which is a drive circuit, is connected to the wiring unit 12. The driver IC outputs a drive signal for selectively driving the piezoelectric unit 10 based on print data from the ink jet printer main body. The carriage 1 having such an ink jet head 6 is configured to be movable in parallel with the paper surface of the recording paper, and is opened to the lower surface side of the droplet discharge head 6 while moving as in the case of a known ink jet printer printer. By ejecting ink downward from the nozzle, an image can be formed on the paper surface.

  2 is an enlarged cross-sectional view of the ink jet head 6 provided in the carriage 1 shown in FIG. 1, and FIG. 3 is a perspective view when the ink jet head 6 is disassembled into a cavity unit 10, a piezoelectric unit 11, and a wiring unit 12. It is. FIG. 4 is an exploded perspective view of the cavity unit 10 and the piezoelectric unit 11, and FIG. 5 is an enlarged exploded perspective view of the cavity unit 10.

  As shown in FIGS. 2 and 4, the cavity unit 10 included in the inkjet head 6 includes a pressure chamber plate 20, a first spacer plate 21, a throttle plate 22, a second spacer plate 23, a first common liquid chamber plate 24, 2 The common liquid chamber plate 25, the damper plate 26, the cover plate 27, and the nozzle plate 28 are laminated from above in this order so that their flat surfaces face each other, and are bonded and joined.

  Among these, the nozzle plate 28 is a resin sheet such as polyimide, and the other plates 21 to 27 are metal plates such as 42% nickel alloy steel plate (42 alloy), and each has a rectangular shape in plan view. , Each has a thickness of about 50 to 150 μm. Each of the plates 20 to 27 is formed with an opening or a recess constituting the liquid flow path (channel) 10a by electrolytic etching, laser processing, plasma jet processing, or the like.

  In the lowermost nozzle plate 28, a large number of nozzle holes 28 a (nozzle diameter 20 μm) for ejecting droplets having a minute diameter are provided at a minute interval along the long side direction (X direction) of the nozzle plate 28. It has been drilled. The nozzle holes 28a are arranged at appropriate intervals in five rows in the Y direction. That is, a plurality of nozzle holes 28a are perforated along the X direction for each ink color, and five nozzle hole rows are arranged along the Y direction. Although not shown, two nozzle hole rows for black ink are arranged from the back side in FIG. 4, and one nozzle hole row for another ink color is arranged for each one row.

  In the pressure chamber plate 20 located in the uppermost layer in the cavity unit 10, a large number of pressure chamber holes 20a are arranged corresponding to each row of the nozzle holes 28a (from the back side in FIG. 2 rows, 1 row each for other ink colors). The pressure chamber hole 20a has an elongated shape in plan view along the short side direction (Y direction) of the pressure chamber plate 20, and is formed so as to penetrate the pressure chamber plate 20 in the plate thickness direction. Are arranged along a direction (Y direction) orthogonal to the row of nozzle holes 28a. And this pressure chamber hole 20a forms the pressure chamber 31 which has internal space by laminating | stacking the piezoelectric unit 11 from upper direction and laminating | stacking the 1st spacer plate 21 from the downward direction.

  The first spacer plate 21 is formed with a communication hole 21a that communicates with one end of the pressure chamber hole 20a, and the second spacer plate 23 (shown in a state of being bonded to the lower surface of the diaphragm plate 22 in FIG. 4). A communication hole 23 a is formed, and a diaphragm plate 22 interposed between these plates 21 and 23 is formed with a throttle hole 22 a having a long hole shape. One end of the throttle hole 22 a communicates with the communication hole 21 a of the first spacer plate 21, and the other end communicates with the communication hole 23 a of the second spacer plate 23. These communication holes 21a and 23a and the throttle hole 22a form a throttle passage 33 that allows the pressure chamber 31 to communicate with a common liquid chamber 35 described later. The restricting hole 22a ejects ink from the nozzle hole 28a, so that when each pressure chamber 31 receives the ejecting pressure, the ink retreating component toward the common liquid chamber 35 is prevented, and the ink is efficiently ejected from the nozzle. It is for making it advance to the hole 28a side.

  The other end of each pressure chamber hole 20a is formed in the first spacer plate 21, the throttle plate 22, the second spacer plate 23, the two manifold plates 25 and 26, the damper plate 26, and the spacer plate 27. The small-diameter communication holes communicated with each nozzle hole 28a of the nozzle plate 28 through a liquid flow path 36 formed in communication with each other.

  In the first common liquid chamber plate 24 and the second common liquid chamber plate 25 located below the second spacer plate 23, the pressure chamber holes 20a are located at lower positions corresponding to the positions in the row direction (X direction). Thus, common liquid chamber holes 24a and 25a extending along the column direction (X direction) are formed through the plate thickness. The common liquid chamber holes 24a and 25a are provided for each ink color corresponding to the nozzle row and the pressure chamber row, specifically, two rows for black ink from the back side of FIG. A total of five rows are provided for each of ink, magenta ink, and yellow ink (see also FIG. 6). Then, a total of five common liquid chambers 35 are formed by stacking the two common liquid chamber plates 24 and 25, covering the upper surface with the second spacer plate 23, and covering the lower surface with the damper plate 26. .

  The damper plate 26 is a surface on the opposite side to the surface facing the common liquid chamber 35, and the portions corresponding to the positions of the common liquid chambers 35 are formed in a thin shape by being recessed from below. A damper wall 26a is provided. Even when the pressure fluctuation generated in the pressure chamber 31 propagates to the common liquid chamber 35 during ink ejection, the damper wall 26a exhibits a damper effect that absorbs and attenuates the pressure fluctuation by elastically deforming and oscillating. Suppresses crosstalk propagating to the other pressure chamber 31 through the common liquid chamber 35. A cover plate 27 is laminated and bonded to the damper plate 26 from below, so that a damper space 26 b is formed between the plates 26 and 27. Although the shape of each damper space 26b will be described in detail later, it is slightly larger (outer dimension is larger) in the outer direction than the planar view contour shape of each common liquid chamber 35. In addition, a nozzle plate 28 having a plurality of nozzle holes 28a is laminated and bonded to the cover plate 27 from below.

In addition, four liquid supply paths 34 are provided for each ink color at one end in the longitudinal direction (X direction) of each plate of the second spacer plate 23 from the pressure chamber plate 20 so as to correspond to the upper and lower positions. The ink from the ink cartridge, which is communicated with the liquid tank 3 (see FIG. 1) and is stationary on the ink jet printer main body (not shown), passes through one end in the longitudinal direction of the common liquid chambers 24a and 25a from the liquid supply path 34. Supplied to the department. Further, each common liquid chamber hole 24 a communicates with the pressure chamber 31 through the throttle passage 33 at the other end. The four liquid supply paths 34 are provided in accordance with the number of ink colors, respectively, whereas five damper chambers, common liquid chambers 24a and 25a, nozzles 28a, and five pressure chambers 31a are provided. The black ink is supplied from one liquid supply path 34 for black ink (the innermost liquid supply path 34 in FIG. 4) to the nozzle hole arrays through the two common liquid chambers 24a and 25a and the two pressure chamber arrays. This is because the black ink is used more frequently than other color inks. A filter 29 having a filtration part 29a corresponding to the liquid supply path 34 is attached to the upper surface of the cavity unit 10 with an adhesive or the like. By laminating and bonding such plates 20 to 28, FIG. And the cavity unit 10 as shown in FIG. 4 is comprised. In the cavity unit 10, ink is supplied from the liquid supply path 34 communicating with the liquid tank 3 to the common liquid chamber 35, and then distributed and supplied to the pressure chamber 31 via the throttle path 33, and the nozzle path 36. Then, a liquid flow path 10a through which ink flows is formed so as to reach the nozzle hole 28a.

  On the other hand, as shown in FIG. 2, the piezoelectric unit 11 is configured by laminating a large number of piezoelectric sheets 40 to 45 and an insulating top sheet 46 (constraint layer). The piezoelectric sheets 40 to 45 are made of a lead zirconate titanate (PZT) ceramic material having a thickness of about 30 μm.

  Among the piezoelectric sheets 40 to 45, a large number of piezoelectric sheets 41 and 43 that are counted upward from the lowermost piezoelectric sheet 40 are arranged on the upper surface so as to individually correspond to the positions of the pressure chambers 31. The individual electrodes 47 are printed and formed in five rows so as to correspond to the respective rows formed by the pressure chambers 31. Further, on the upper surface of the odd-numbered piezoelectric sheets 40, 42, 44 counted upward from the lowermost piezoelectric sheet 40, a common electrode is arranged so as to cover all the individual electrodes 47 for each row when viewed in plan. 48 is printed. The individual electrodes 47 and the common electrode 48 are relay wirings (not shown) provided on the side end surfaces of the piezoelectric sheets 40 to 45 and the top sheet 46 or through holes (not shown) (configured by filling or applying a conductive adhesive or the like). Are electrically connected to the respective external electrodes 49 (see also FIG. 3) provided on the upper surface of the top sheet 46. The piezoelectric unit 11 is bonded and fixed to the cavity unit 10 with each individual electrode facing each pressure chamber 31 of the cavity unit 10. The common electrode 48 is grounded through a through hole. The external electrode 49 is screen-printed using an Ag—Pd-based conductive material.

  One end of the wiring unit 12 is laminated and joined to the upper surface of the piezoelectric unit 11, and the other end is drawn in a direction (Y direction) perpendicular to the row direction of the nozzle holes 28a. The wiring unit 12 is a flexible strip-shaped wiring member, and has one of its ends having a plurality of power supply terminals 50 corresponding to the external electrodes 49 on the top surface of the piezoelectric unit 11. It is electrically connected to an IC chip 51 (see FIG. 3) including a drive circuit mounted on the middle part pulled out to the other end side. In the wiring unit 12, a lead wire (not shown) for inputting / outputting a drive signal to / from the IC chip 51 is wired along the lead-out direction (Y direction) via the IC chip, and the IC chip and each power supply terminal 50 are connected to each other. Electrically connected. Further, solder bumps are formed on the power supply terminals 50, and the power supply terminals 50 and the external electrodes 49 are electrically connected to the piezoelectric unit 11 and the wiring unit 12 stacked on the upper surface thereof via the solder bumps. The

  A portion of the piezoelectric sheet sandwiched between the plurality of individual electrodes 47 and the common electrode 48 that overlap with each other when viewed in the stacking direction with respect to one pressure chamber 31 follows the print data from the main body side. By selectively outputting a drive signal from the IC chip 51, an active portion that is deformed and driven is formed, and an ejection pressure is applied to the ink in the pressure chamber 31 by the deformation of the active portion.

  The ink jet head 6 having such a configuration operates as follows and discharges liquid from the nozzle hole 28a. That is, the liquid supplied from the liquid tank 3 through a filter (not shown) is filled in the liquid flow path 10 a including the liquid supply path 34, the common liquid chamber 35, the throttle path 33, the pressure chamber 31, and the nozzle path 36. ing. In this state, when a potential is applied from the wiring unit 12 to the piezoelectric unit 11 and the plurality of individual electrodes 47 are selectively set to a predetermined potential, a potential difference is generated between the individual electrode 47 to which the potential is applied and the common electrode 48, An electric field acts on the active portions of the piezoelectric sheets 41 to 44 to cause distortion in the stacking direction. When the active portion is deformed in this way, the lowermost piezoelectric sheet 40 protrudes into the pressure chamber 31, so that the internal pressure of the pressure chamber 31 rises and the ink in the pressure chamber 31 changes to the ink in the nozzle passage 36. The pressure wave is propagated and ink is ejected to the outside from the nozzle hole 28a.

  In addition, the pressure wave generated by the increase in the internal pressure of the pressure chamber 31 includes not only a forward component toward the nozzle hole 28 a but also a backward component toward the common liquid chamber 35. The backward component is attenuated by the throttle passage 33 having a smaller sectional area than the surroundings, and the remaining pressure wave is absorbed by the elastic deformation of the damper wall 26a. This suppresses the pressure wave generated in one pressure chamber 31 from reaching the other pressure chamber 31 via the common liquid chamber 35. The absorption of the pressure wave can be performed only by elastic vibration of the damper wall 26a, but can also be used together with the air in the damper space 16b.

  The 26 configuration of the damper plate of this embodiment will be described in detail.

  FIG. 6 is a plan view showing the configuration of the second common liquid chamber plate 25 and the damper plate 26 laminated and bonded to each other, and shows the configuration when viewed from the second common liquid chamber plate 25 side. FIG. 7 is an enlarged partial cross-sectional view showing the configuration when the second common liquid chamber plate 25 and the damper plate 26 are cut along the line V-V shown in FIG.

As shown in FIG. 6, the second common liquid chamber plate 25 is formed with five rows of common liquid chamber holes 25a arranged in the Y direction, and the two adjacent rows on the right side of FIG. For black ink, the other three are common liquid chamber holes for inks of other colors (magenta, cyan, yellow). The common liquid chamber holes 25a are both forms of the slender hole shape length L ₁ along the longitudinal direction (X direction) of the second common liquid chamber plate 25, and has a width dimension W _1. Further, the second common liquid chamber plate 25 has a plurality of through holes 25b forming nozzle passages 36 along the respective common liquid chamber holes 25a. The two adjacent rows on the right side of FIG. The other three rows are formed for each color for the other color inks. The common liquid chamber hole 24a of the first common liquid chamber plate 24 has the same shape as the common liquid chamber 25a.

The damper plate 26 bonded to the lower side of the second common liquid chamber plate 25 is formed with a damper wall 26a (indicated by a broken line in FIG. 6) at a position corresponding to each common liquid chamber hole 25a. The damper wall 26a has a contour shape in plan view (that is, when viewed along the stacking direction of the plates 25 and 26) larger than the contour shape of the common liquid chamber hole 25a. The damper wall 26a corresponding to the hole 25a has a width dimension W ₂ (> W ₁ ) and a length dimension L ₂ (> L ₁ ). As shown in FIG. 6, each common liquid chamber hole 25a has some differences in size and shape, but the shape and dimensions of the damper wall 26a correspond to the contour shape of each common liquid chamber hole 25a. It is formed so as to become large.

Further, as shown in FIG. 7, the damper wall 26a has a thickness (thin wall) thinner than the thickness dimension of the damper plate 26, that is, the thickness dimension T ₁ (for example, 50 μm) of the plate before the damper wall 26a is formed. Is formed. Specifically, as shown in FIG. 7, the central portion 26 c positioned so as to overlap and face the region of the common liquid chamber 35 in a plan view has an inside of the common liquid chamber 35 due to the discharge pressure flowing backward from the pressure chamber 31. The peripheral portion of the damper wall 26a having an elongated hole shape in plan view has a thinner portion 26d that is thinner than the thickness dimension T ₂ (for example, 15 μm) of the central portion 26c. The thin-walled portion 26d is extended along the periphery of the damper wall 26a so as to reach the entire periphery.

Further, the thinnest part 26d, which is the peripheral part of the damper wall 26a, has the thinnest part 26e having the smallest thickness dimension T ₃ (for example, 8 μm) on the inner side (closer to the center part) than the outer edge. It is formed so as to extend. Cross section (i.e., a width direction orthogonal to the extending direction of the thin portion 26 d (X direction) (Y-direction) cross-section along), the damper wall 26a of the width W ₂ along the Y direction, of the central portion thickness T _2, in thin walled portion 26d than the width direction of both end (periphery) of thickness T _2, the thinnest part 26e of the smallest thickness T ₃ to slightly above the central portion than at both ends is formed Yes. In the present embodiment, the thinnest portion 26e is formed at a substantially central portion in the width direction (Y direction) in the thin portion 26d.

In the damper plate 26 and the second common liquid chamber plate 25, the central portion 26c of the damper wall 26a overlaps the common liquid chamber hole 25a in plan view, and the thin wall portion 26d at the peripheral portion overlaps the common liquid chamber hole 25a. And is laminated and bonded to the lower surface of the second common liquid chamber plate 25 (on the damper plate 26 side). In particular, the thinnest portion 26e is disposed so as to be bonded to the lower surface of the second common liquid chamber plate 25. (See also Fig. 5)
Although FIG. 7 shows the damper wall 26a corresponding to one common liquid chamber hole 25a arranged on the leftmost side, the thin wall portion is similarly applied to the damper wall 26a corresponding to the other common liquid chamber hole 25a. 26d and the thinnest part 26e are formed, the central part 26c is opposed to each common liquid chamber hole 25a, the thinnest part 26e and the thin part 26d are outside the common liquid chamber hole 25a, and the second part It arrange | positions so that it may adhere | attach with the lower surface side of a common plate. Further, since the thin portion 26d and the thinnest portion 26e are formed in the entire peripheral portion of the damper wall, the thin wall portion is thinner than the central portion 26d on the longitudinal section side (X direction) which is the longitudinal direction of the damper wall. The thinned portion 26d and the thinnest portion 26e are formed, but at least the thin-walled portion 26d and the thinnest portion 26e on the side of the cross section (Y direction side) are bonded to face the lower surface of the second common liquid chamber plate 25. It is preferable.

FIG. 8 is a schematic diagram for explaining an example of a manufacturing method for forming the damper wall 26 a as described above on the damper plate 26. As shown in FIG. 8, resists 70 and 71 are laminated on both surfaces of a flat plate 260 to be a flat damper plate 26, and a region A ₁ corresponding to the damper wall 26a on the surface of the resist 70 on one surface. A mask 71 is applied to a region A ₂ other than the above. Then, the area A ₁ is exposed and developed, whereby the area A ₁ in the resist 70 is removed to partially expose one surface of the flat plate 260.

Next, such a flat plate 260 is moved at a predetermined speed in a space S in which a predetermined etching solution is sprayed from above and below and is filled in a mist. As a result, the exposed portion of the region A ₁ not covered by the resist 70 is half-etched to form a concave shape, and a damper wall 26a having a smaller thickness than the surrounding region A ₂ is formed on the bottom wall. A damper space 26b is formed in the concave portion removed by etching, and a damper plate 26 having such a damper wall 26a and a damper space 26b is formed. At this time, between the damper plate 26 (flat plate 260) moves the space S, with accumulated on the exposed portion of the etching solution region A _1, easily flows along the periphery of the region A _1. Therefore, the peripheral edge portion is dissolved deeper than the central portion 26c, and the thin portion 26d and the thinnest portion 26e as described above are formed.

  As shown in FIG. 7, the damper plate 26 has a second common liquid chamber plate 25 such that a thin portion 26d that circulates in a plan view is positioned outward from the peripheral edge of the common liquid chamber hole 25a. And laminated. More specifically, the surface of the damper plate 26 opposite to the side where the damper space 26 b opens is opposed to the second common liquid chamber plate 25. The plates 25 and 26 are laminated and bonded to each other so that at least the thinnest portion 26e of the thin portion 26d that circulates around the peripheral portion of the damper wall 26a is located outside the common liquid chamber hole 25a. .

  The central portion 26c of the damper wall 26a is half-etched while being controlled so as to have a thickness necessary for absorbing the backward component of the pressure wave. In addition, FIG. 8 illustrates a state in which one row of damper walls 26a is manufactured with respect to one flat plate 260 to be the damper plate 26, but other damper wall 26a rows are formed simultaneously, As known from Japanese Patent Laid-Open No. 2002-192732, it is possible to simultaneously manufacture a plurality of damper plates 26 by etching the entire lead frame in which a plurality of flat plates 260 to be a plurality of damper plates 26 are connected by connecting pieces. It is.

  According to the cavity unit 10 for the inkjet head 6 described above, the planar view contour shape of the damper wall 26 is larger than the planar view contour shape of the common liquid chamber hole 25a at a position corresponding to the common liquid chamber hole 25a. Therefore, when the damper wall 26a is manufactured by half-etching, even if the peripheral edge portion is thinner than the central portion 26c (even if the thin portion 26d is formed), the thin portion 26d , Located outside the common liquid chamber hole 25a and bonded to the lower surface side of the second common liquid chamber plate 25 (adhesion allowance). Therefore, even if a defect or a through-hole is formed in the thin-walled part 26d of the damper wall 26a while the damper effect is secured at the central part 26c due to a drop of contaminants or the like, It is possible to suppress communication between the common liquid chamber 35 and the damper space 26b.

  In particular, since the thinnest portion 26e that is most likely to be lost due to the removal of contaminants is disposed so as to be positioned outside the common liquid chamber 35, the risk of ink leakage is further reduced, and the product Reliability can be maintained. Further, even when the amount of contaminants in the ingot, which is a material used for the damper plate 26, is increased (using a low-purity ingot), if the configuration as in the present embodiment is adopted, defects or penetrations due to the loss of contaminants will occur. Since ink leakage can be prevented by forming the holes, the cost of the damper plate material can be reduced.

  Further, according to the above configuration, the upper surface of the thin portion 26d (that is, the surface opposite to the damper space 26b) and the lower surface of the second common liquid chamber plate 25 can be bonded. In this case, since the thin part 26d is fixed to the second common liquid chamber plate 25 on its upper surface, it is advantageous because it is possible to suppress the dropout of contaminants from the thin part 26d itself.

  In the configuration of this embodiment, since the damper effect can be improved if the damper wall 26a at the position facing the common liquid chamber 35 is thin, the thin portion 26d is slightly closer to the common liquid chamber hole (inward). In this case, the thinnest portion 26e inside the ridge line of the thin-walled portion 26d is positioned outside the peripheral portion of the common liquid chamber hole 25a. Is preferred.

  The present invention can be applied not only to an inkjet head that ejects ink, but also to a cavity unit for a droplet ejection head that ejects droplets in which a common liquid chamber plate and a damper plate are stacked and bonded.

FIG. 4 is a cross-sectional view of a carriage on which a liquid discharge head including a cavity unit according to the present embodiment is mounted, and illustrates an inkjet printer head as a droplet discharge head. It is an expanded sectional view of the inkjet head with which the carriage shown in FIG. 1 is provided. It is a perspective view when an ink jet head is disassembled into a channel unit, a piezoelectric unit, a wiring unit, and a support frame. It is a disassembled perspective view of a cavity unit and a piezoelectric unit. It is an expansion disassembled perspective view of a cavity unit. It is a top view which shows the structure of the 2nd common liquid chamber plate and damper plate which were mutually laminated | stacked, and it has shown the structure when it sees from the 2nd common liquid chamber plate side. It is a fragmentary sectional view which expands and shows the structure when the 2nd common liquid chamber plate and damper plate are cut | disconnected by the VV arrow line shown in FIG. It is a schematic diagram for demonstrating an example of the manufacturing method which forms a damper wall in a damper plate.

Explanation of symbols

6 Inkjet head (droplet discharge head)
DESCRIPTION OF SYMBOLS 10 Cavity unit 10a Liquid flow path 11 Actuator 25 2nd common liquid chamber plate 25a Common liquid chamber hole 26 Damper plate 26a Damper wall 26b Damper space 26c Center part 26d Thin part 26e Thinnest part

Claims (2)

It has a liquid flow path that reaches a plurality of nozzle holes arranged in parallel through a plurality of pressure chambers arranged in the middle, and applies pressure to the liquid in the pressure chamber to discharge the liquid from the nozzle holes. A cavity unit for a droplet discharge head on which an actuator is stacked,
A common liquid chamber plate in which a common liquid chamber hole that forms a common liquid chamber that guides liquid from a liquid supply source to the plurality of pressure chambers is formed in a long hole shape along the parallel direction of the pressure chambers;
A wall portion laminated and bonded to the common liquid chamber plate, the surface opposite to the surface facing the common liquid chamber plate is recessed, and a part of the wall is left on the common liquid chamber side. And a damper plate that forms a damper wall that relieves pressure fluctuations in the room,
The damper wall has a contour shape larger than the contour shape of the common liquid chamber hole when viewed along the stacking direction of the plates , and a peripheral portion has a thin portion having a thickness dimension smaller than that of the central portion. Extended ,
The common liquid chamber plate and the damper plate are bonded in a state where the thin portion is located outside the common liquid chamber hole when viewed along the stacking direction ,
Furthermore, the thin-walled portion has a thinnest portion having the smallest thickness dimension in the middle portion of the cross section perpendicular to the extending direction of the thin-walled portion, and when the thinnest portion is viewed along the stacking direction. A cavity unit for a droplet discharge head, wherein the cavity unit is located outside the common liquid chamber hole . 2. The droplet discharge head for a droplet ejection head according to claim 1, wherein the damper wall is formed by half-etching the region with an etchant, wherein the damper plate is masked in regions other than the region corresponding thereto. Cavity unit.

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