JP2018144474A - Droplet injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress pressure fluctuations generated within a common liquid chamber.SOLUTION: A channel unit, which is formed in such a manner that a plurality of laminated plates are stacked, has a first damper chamber that is extended to overlap a plurality of pressure chambers in such a manner that a direction of arrangement of the pressure chambers is set to be a longitudinal direction, when seen from the side where a plurality of nozzles are opened. At a height along a lamination direction in which the plurality of laminated plates are stacked, the first damper chamber is arranged at a height between the pressure chamber and a common liquid chamber. A first support part is provided within the first damper chamber.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a droplet ejecting apparatus.

  As a liquid droplet ejecting apparatus that ejects liquid droplets from nozzles, an apparatus configured to eject liquid droplets individually from a plurality of nozzles by selectively applying pressure to a liquid in a pressure chamber is known. . In this liquid droplet ejecting apparatus, when a liquid droplet is ejected from a certain nozzle, the residual pressure in the pressure chamber communicating with that nozzle propagates to another pressure chamber via the common liquid chamber. In some cases, droplet ejection from a nozzle different from the ejected nozzle may be affected.

  In Patent Document 1, a plurality of damper chambers are provided between the common liquid chamber and the plurality of pressure chambers so as to have the same pitch as the plurality of pressure chambers, and a communication hole communicating with the common liquid chamber is provided in the damper chamber. Thus, a technique for suppressing pressure fluctuation generated in the common liquid chamber is disclosed.

JP 2012-192641 A

  In order to improve droplet ejection accuracy in a droplet ejecting apparatus, it is conceivable to employ a configuration in which a plurality of nozzles are arranged at high density. Arranging a plurality of nozzles at high density means that the pressure chambers communicating with the nozzles are also arranged at high density. When the technique of Patent Document 1 is used, a plurality of damper chambers arranged at the same pitch as the plurality of pressure chambers are also arranged at a high density. For this reason, each damper chamber itself is inevitably reduced in size, and there is a possibility that the effect of suppressing the pressure fluctuation generated in the common liquid chamber cannot be sufficiently obtained.

  An object of the present invention is to provide a droplet ejecting device that suppresses pressure fluctuations that occur in a common liquid chamber even when nozzles or pressure chambers are arranged at high density.

  A droplet ejecting apparatus according to an aspect of the present invention includes a plurality of nozzles, a plurality of pressure chambers each communicating with each of the plurality of nozzles, and a common liquid chamber communicating with the plurality of pressure chambers. A flow path unit in which a liquid flow path is formed, and an actuator that selectively applies pressure to the liquid in the plurality of pressure chambers, and the flow path unit is formed by laminating a plurality of laminated plates. The flow path unit further includes a first damper chamber extending so as to overlap the plurality of pressure chambers with a direction in which the plurality of pressure chambers are arranged as a longitudinal direction when viewed from a side where the plurality of nozzles are opened. The first damper chamber is disposed at a height between the pressure chamber and the common liquid chamber at a height along the stacking direction in which the plurality of stacked plates are stacked, In the first damper chamber There is a first supporting portion to, characterized in that.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where a nozzle or a pressure chamber is arrange | positioned with high density, the droplet ejecting apparatus which suppresses the pressure fluctuation which generate | occur | produces in a common liquid chamber can be provided.

It is a schematic plan view of an inkjet printer. It is a top view of an inkjet head. FIG. 3 is a partially enlarged view of FIG. 2. (A) is the sectional view on the IVA-IVA line of FIG. 3, (b) is the sectional view on the IVB-IVB line of FIG. It is a top view of an inkjet head. FIG. 6 is a partially enlarged view of FIG. 5. It is the VII-VII sectional view taken on the line of FIG. It is a top view of an inkjet head.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. However, the relative arrangement of the constituent elements described in this embodiment, the device shape, and the like are merely examples, and the scope of the present invention is not intended to be limited thereto. In the embodiments described below, an example of an ink jet printer that includes an ink jet head that ejects ink droplets onto a recording sheet will be described as an example of a droplet ejecting apparatus.

<Embodiment 1>
First, a schematic configuration of the inkjet printer 1 of the present embodiment will be described. FIG. 1 is a schematic plan view of an ink jet printer 1 according to the present embodiment. The ink jet printer 1 includes an ink jet head 3 for recording an image or the like on a recording paper 2, a carriage 4 configured to reciprocate along the scanning direction of FIG. 1, and transporting the recording paper 2 perpendicular to the scanning direction. And a transport mechanism 5 for transporting in the direction. A platen 7 that supports the recording paper 2 is provided in the printer housing 6 along the horizontal direction. Above the platen 7, two guide rails 8a and 8b extending in parallel with the scanning direction are provided. The carriage 4 is driven by a carriage drive motor (not shown), and moves in the scanning direction along the two guide rails 8a and 8b in a region facing the recording paper 2 on the platen 7.

  The inkjet head 3 is attached to the lower part of the carriage 4 along the horizontal direction with a gap between the inkjet head 3 and the platen 7. The lower surface of the inkjet head 3 is a droplet ejecting portion 3a. The ink jet head 3 is connected to the ink cartridge holder 9 by a tube (not shown). Four ink cartridges 10 a, 10 b, 10 c, and 10 d are mounted on the ink cartridge holder 9. The four ink cartridges 10a, 10b, 10c, and 10d are filled with magenta, cyan, yellow, and black inks, respectively. These inks are supplied to the inkjet head 3 through a tube. When the inkjet head 3 is not used, the inkjet head 3 moves to above the maintenance unit 11 along the guide rails 8a and 8b.

  The maintenance unit 11 is provided with a cap 12, a suction pump 13, a wiper 14, and the like. The cap 12 is driven up and down by a cap drive unit (not shown) configured by a drive source such as a motor and a power transmission mechanism such as a gear. The cap 12 is moved upward by the cap driving unit and is capped by being in close contact with the droplet ejecting unit 3a of the inkjet head 3. After capping, the suction pump 13 connected to the cap 12 sucks air inside the cap 12 and decompresses the inside of the cap 12. As a result, the suction purge for forcibly discharging the ink into the cap 12 from the droplet ejecting portion 3a of the inkjet head 3 is performed. By this suction purge, bubbles and dust mixed in the ink or ink having increased viscosity is discharged. By such processing, it is suppressed that the quality of the droplet ejection is deteriorated. The wiper 14 is arranged to perform wiping to wipe off ink adhering to the droplet ejecting portion 3a of the inkjet head 3 when the inkjet head 3 moves to the droplet ejecting position after the suction purge.

  As described above, the ink jet printer 1 ejects liquid droplets while moving the ink jet head 3 in the scanning direction while transporting the recording paper 2 toward the recording paper discharge unit 15 by the transport mechanism 5. With such an operation, the inkjet printer 1 is configured to record images, characters, and the like on the recording paper 2.

  The structure of the inkjet head 3 will be described in detail with reference to FIGS. FIG. 2 is a plan view of the inkjet head 3. FIG. 3 is a partially enlarged view in which the portion a of FIG. 2 is enlarged. 4 is a longitudinal sectional view of FIG. 3, FIG. 4 (a) is a sectional view taken along line IVA-IVA in FIG. 3, and FIG. 4 (b) is a sectional view taken along line IVB-IVB in FIG. As shown in FIGS. 2 to 4, the inkjet head 3 includes a flow path unit 31 in which a liquid flow path (ink flow path) including a nozzle 45 and a pressure chamber 43 is formed. The inkjet head 3 includes a piezoelectric actuator 32 that can selectively apply pressure to ink in the pressure chamber 43 according to a recording signal or the like.

  As shown in FIG. 4, the flow path unit 31 in this embodiment is comprised from 11 laminated plates as follows. First, the cavity plate 20, the base plate 21, the aperture plate 22, the spacer plate 23, the first damper plate 24, and the second damper plate 25. A first manifold plate 26, a second manifold plate 27, a third damper plate 28, a cover plate 29, and a nozzle plate 30. These plates 20 to 30 are joined to each other by an adhesive, and of the plates 20 to 30, except for the lowermost nozzle plate 30, the plates 20 to 29 are each a metal plate such as a stainless steel plate or a nickel alloy steel plate. is there. On the other hand, the lowermost nozzle plate 30 is formed of a synthetic resin material such as polyimide. These are merely examples, and the number of laminated plates is not limited to the example shown in FIG. Thus, the flow path unit is formed by laminating a plurality of laminated plates. A direction in which the laminated plates are laminated (vertical direction in FIG. 4) is defined as a lamination direction.

  As shown in FIG. 2, four ink supply holes 40 are provided in the flow path unit 31 that is a stacked body of the plates 20 to 30. The four ink supply holes 40 are connected to ink cartridges of four colors (magenta, cyan, yellow, and black), respectively. The flow path unit 31 is provided with four common liquid chambers 41. The four common liquid chambers extend linearly with the ink supply hole 40 as one end and communicate with the four ink supply holes 40, respectively. As shown in FIGS. 2 to 4, the individual ink flow from the common liquid chamber 41 to the nozzle 45 through the second communication channel 46, the aperture 42, the pressure chamber 43, and the first communication channel 44. Many roads are provided. Thus, the common liquid chamber 41 has a so-called manifold structure in which a plurality of flow paths branch from the common liquid chamber 41. The aperture 42 is a throttle channel, and the second communication channel 46 has a small channel area in the aperture 42.

  The flow channel structure of the flow channel unit 31 will be described in detail. The nozzle plate 30 in the lowermost layer of the flow path unit 31 includes four nozzle rows in which a plurality of nozzles 45 are arranged at a predetermined pitch in the transport direction. In the four nozzle rows, four colors of ink are ejected, respectively. The cavity plate 20 located in the uppermost layer is formed with a plurality of pressure chambers 43 arranged at a predetermined pitch in the transport direction like the nozzle 45, and constitutes four pressure chamber rows. Further, the plates 21 to 29 between the cavity plate 20 and the nozzle plate 30 are respectively formed with through holes constituting the first communication flow path 44 that allows the pressure chamber 43 and the nozzle 45 to communicate with each other.

  As shown in FIG. 2, four ink supply holes 40 that supply the four color inks respectively supplied from the four ink cartridges to the common liquid chamber 41 are scanned at one end in the conveyance direction of the cavity plate 20. It is formed side by side in the direction. The common liquid chamber 41 is formed corresponding to each of the four pressure chamber rows. That is, in the example of FIG. 2, four common liquid chambers 41 are formed. One common liquid chamber 41 communicates with a pressure chamber 43 belonging to one corresponding pressure chamber row. Although not shown, these four common liquid chambers 41 are respectively connected to the four ink supply holes 40 formed in the cavity plate 20 through the communication channels formed in the five plates 21 to 25. Communicate. A plurality of second communication channels 46 are formed in the five plates 21 to 25 between the cavity plate 20 and the two manifold plates 26 and 27. The plurality of second communication channels 46 are channels in which one common liquid chamber 41 and a plurality of pressure chambers 43 corresponding to the common liquid chamber 41 communicate with each other.

  When the plates 20 to 30 described above are joined in a stacked state, the ink flow path from the ink supply hole 40 to the common liquid chamber 41 and the common liquid chamber 41 to the pressure chamber 43 are formed in the flow path unit 31. A second communication channel 46 and a pressure chamber 43 are formed. In addition, an individual ink flow path is formed from the pressure chamber 43 to the nozzle 45 via the first communication flow path 44.

  The two types of damper chambers 47 and 48 will be described. In the flow path unit 31 of the present embodiment, in addition to the flow paths described above, a first damper chamber 47 and a second damper chamber 48 for attenuating pressure fluctuations in the common liquid chamber 41 are formed. Has been. The first damper chamber 47 and the second damper chamber 48 are arranged so as to sandwich the common liquid chamber 41 in the vertical direction (the stacking direction of the plates 20 to 30). That is, the common liquid chamber 41 is disposed between the first damper chamber 47 and the second damper chamber 48 in the vertical direction. The first damper chamber 47 is installed above the common liquid chamber 41. More specifically, the first damper chamber 47 is formed between the pressure chamber 43 and the common liquid chamber 41 at a height along the stacking direction in which a plurality of stacked plates are stacked. . The first damper chamber 47 is preferably formed on a line connecting the pressure chamber 43 and the common liquid chamber 41. However, if the first damper chamber 47 is formed so that the height in the stacking direction is located between the two, You may form in the position which shifted | deviated from the line which connected both. The second damper chamber 48 is installed below the common liquid chamber 41. As shown in FIG. 4, the first damper chamber 47 is formed by the first damper plate 24 and the second damper plate 25. As shown in FIG. 2, the first damper chamber 47 extends in the transport direction so as to face the common liquid chamber 41 in the stacking direction. As shown in FIGS. 2 to 4, the first damper chamber 47 is installed so as to cover the common liquid chamber 41. That is, the width of the first damper chamber 47 in the scanning direction and the conveying direction (direction perpendicular to the plate stacking direction) in FIG. 2 is equal to or larger than the width of the common liquid chamber 41. The partition wall 25d between the first damper chamber 47 and the common liquid chamber 41 shown in FIG. 4A functions as a damper film that deforms due to pressure fluctuations generated in the common liquid chamber 41. For this reason, the width of the first damper chamber 47 is preferably wide. Therefore, in the present embodiment, the first damper chamber 47 is installed so as to cover the common liquid chamber 41. As shown in FIGS. 2 and 3, the first damper chamber 47 has a plurality of pressure chambers when the flow path unit 31 is viewed from the side where the plurality of nozzles 45 are opened, that is, in the bottom view of FIGS. 43 so as to overlap with 43. The longitudinal direction of the first damper chamber 47 extends in a direction along the direction in which the plurality of pressure chambers 43 are arranged. For this reason, even when the nozzles or pressure chambers are arranged at high density, they are arranged so as to overlap the plurality of pressure chambers 43. Thereby, even if a nozzle or a pressure chamber is densified, the pressure fluctuation which generate | occur | produces in a common liquid chamber can be suppressed favorably. Moreover, since the area of the partition wall 25d that functions as a damper film can be provided wide, it is possible to suppress pressure fluctuations that occur in the common liquid chamber. Further, the second damper chamber 48 is arranged below the common liquid chamber 41, so that the pressure fluctuation in the common liquid chamber 41 is further suppressed. The surface opposite to the surface shown in FIG. 2 is a surface (opening surface) where the plurality of nozzles 45 of the flow path unit 31 are opened, and when viewed from the side where the nozzles 45 are opened, a position corresponding to the opening surface It means to see the opening surface from. In the present embodiment, such first damper chamber 47 suppresses pressure fluctuations. However, since the first damper chamber 47 increases in the direction in which the pressure chambers 43 are arranged, the deformation of the pressure chamber 43 may be excessively large. There is. For this reason, a first support portion 70 is formed in the first damper chamber 47. Details of the first support portion 70 will be described later.

  Next, a method for forming the first damper chamber 47 will be described in detail. First, in the first damper plate 24, a through hole 24a arranged in the longitudinal direction (conveying direction) of the common liquid chamber 41 in a portion facing the common liquid chamber 41 (a portion covering the common liquid chamber 41 as described above). Is formed. In the example of FIG. 2, since four common liquid chambers 41 are provided, the four through holes 24a are formed side by side in the transport direction.

  Next, in the second damper plate 25, a concave portion 25a opened upward is formed on the upper surface of the portion facing the through hole 24a in the stacking direction. Since the recess 25a is formed on the upper surface of the portion facing the through hole 24a of the first damper plate 24, the first damper plate 24 and the second damper plate 25 are laminated on the upper surface of the recess 25a. In some cases, space will be created. In addition, in the second damper plate 25, the concave portion 25a is formed, and a convex portion 25b and a communication hole 25c for communicating the second damper plate 25 including the convex portion 25b are formed on the concave portion 25a. The As will be described later, the convex portion 25 b forms a part of the first support portion 70. As shown in FIGS. 3 and 4, the convex portion 25 b (a part of the first support portion 70) is formed below the position where the pressure chamber 43 is formed in the stacking direction. As shown in FIG. 4B, at the position where the convex portion 25b is not formed, a space is generated on the upper surface of the concave portion 25a when the first damper plate 24 and the second damper plate 25 are laminated. become. 4B shows a cross section at a position where the communication hole 25c is included, the cross section at a position where neither the communication hole 25c nor the convex portion 25b is formed is as shown by a dotted line in FIG. 4A. A space is created on the upper surface of the recess 25a. The communication hole 25 c is a hole that communicates the common liquid chamber 41 and the first damper chamber 47.

  Thereafter, the upper portion of the space formed by the through hole 24 a and the recess 25 a is closed by the spacer plate 23, whereby the first damper chamber 47 is formed above the common liquid chamber 41. Moreover, the 1st support part 70 mentioned later is also formed. The first damper chamber 47 is in a state where air is present inside. As described above, the partition wall 25d functions as a damper film that is deformed by the pressure fluctuation generated in the common liquid chamber 41, so that the pressure fluctuation generated in the common liquid chamber 41 can be attenuated.

  In the present embodiment, as shown in FIG. 2, the first damper chamber 47 has an oval shape in plan view, but the first damper chamber 47 is not limited to the oval shape, and air exists. Any shape that can satisfy the function of the damper film may be used.

  The spacer plate 23 is formed with a convex portion 23 a at a position facing the convex portion 25 b of the second damper plate 25. Therefore, when the first damper chamber 47 is formed, the convex portion 23 a formed on the spacer plate 23 overlaps with the convex portion 25 b formed on the concave portion 25 a of the second damper plate 25. Thereby, the first support portion 70 is formed in the first damper chamber 47. The first support part 70 supports the pressure chamber and the first damper chamber. As a result, the pressure chamber is easily deformed as the first damper chamber expands in the direction in which the pressure chambers are arranged, and the effect of suppressing the deformation of the pressure chamber and the first damper chamber is exhibited. To do. As shown in FIG. 2, a plurality of first support portions 70 are provided inside the first damper chamber 47 corresponding to each pressure chamber row. The plurality of first support portions 70 are formed at the same pitch as the plurality of pressure chambers 43 (or the plurality of nozzles 45). Note that even if there is a pitch shift due to a manufacturing error or the like, the pitch is regarded as the same. Within the first damper chamber 47 corresponding to each pressure chamber row, a region where the first support portion 70 is formed and a region where the first support portion 70 is not formed are arranged in a direction in which a plurality of pressure chambers are arranged. It is continuous along. The first support portion 70 functions to increase the rigidity of the pressure chamber 43. When pressure for ejecting droplets is applied to the pressure chamber 43, excessive deformation of the pressure chamber 43 is suppressed by the first support portion 70. For this reason, it is possible to efficiently eject droplets without dispersing pressure necessary for droplet ejection. In the example of FIG. 4, the first support portion 70 is formed below the pressure chamber 43 in the plate stacking direction, but is not limited thereto. That is, it may be formed at a position that does not overlap with the pressure chamber 43 in plan view. Further, the first support portion 70 can suppress bending deformation that occurs in the pressure chamber 43. A suitable shape of the first support portion 70 for suppressing the bending deformation generated in the pressure chamber 43 is preferably a shape along the longitudinal shape of the pressure chamber 43 as shown in FIG. In addition, as a preferable shape when torsional deformation occurs in the pressure chamber 43, the shape of the first support portion 70 that overlaps a line connecting the corner portions of the pressure chamber 43 diagonally in order to obtain torsional rigidity. Is preferred. It is preferable that the first support portion 70 is formed in contact with two opposing surfaces constituting the first damper chamber 47.

  In addition, the formation method of the 1st damper chamber 47 mentioned above is only an example, and is not restricted to this example. For example, in the example of FIG. 4A, the upper surface of the convex portion 25b is shown as being formed at the same position as the upper surface of the second damper plate 25 in the stacking direction of the plates. It may be formed below the upper surface of 25. Even in this case, the upper portion is blocked by the spacer plate 23, so that the first support portion 70 is formed. In addition, the above-described first support portion 70 is illustrated as being formed at a position where a space is opened in the longitudinal direction of the pressure chamber 43 (scanning direction in FIG. 2) in the longitudinal section shown in FIG. However, it is not limited to this. The first support portion 70 may be formed in contact with the side wall surface inside the first damper chamber 47 (one of the left and right surfaces in FIG. 4).

  As described above, the communication hole 25 c is formed so as to communicate the first damper chamber 47 and the common liquid chamber 41. With such a configuration, when a large pressure fluctuation occurs in the common liquid chamber 41, not only the partition wall 25d is deformed, but also the pressure fluctuation in the common liquid chamber 41 causes the air in the first damper chamber 47 to be deformed. Communicate directly to. For this reason, the effect of suppressing pressure fluctuation can be obtained. The communication hole 25c has a straight hole shape in which the hole diameter (hole cross-sectional area) does not change in the hole axis direction. The diameter of the communication hole 25c is, for example, 70 to 150 μm, and can be made larger than the diameter of the nozzle 45 (for example, 15 to 20 μm). In the example of FIG. 2, the communication holes 25c are formed one by one at a predetermined pitch interval in the row direction of the pressure chamber row, but are not limited to this example. A plurality of the pressure chambers may be formed at predetermined pitch intervals in the row direction of the pressure chamber row. That is, a plurality of communication holes 25c may be formed in FIG.

  Next, a method for forming the second damper chamber 48 will be described in detail. The second damper chamber 48 is formed by a third damper plate 28 located on the lower side in the stacking direction of the two manifold plates 26 and 27. In the third damper plate 28, a recess 28 a extending in the longitudinal direction of the common liquid chamber 41 is formed on the lower surface of the portion facing the common liquid chamber 41 in the stacking direction. The concave portion 28 a is closed below by the lower cover plate 29 in the stacking direction, whereby the second damper chamber 48 is formed below the common liquid chamber 41. Similar to the first damper chamber 47, the width of the second damper chamber 48 can be greater than or equal to the width of the common liquid chamber 41. In the example of FIG. 4, the width of the second damper chamber 48 is substantially the same as the width of the first damper chamber 47, but may be a different size.

  Similarly to the first damper chamber 47, the second damper chamber 48 is in a state where air is present therein, and the partition wall 28b between the common liquid chamber 41 and the second damper chamber 48 is provided with a common liquid. It functions as a damper film that is deformed by pressure fluctuations generated in the chamber 41. Thereby, the pressure fluctuation generated in the common liquid chamber 41 is suppressed. Further, a second support portion (not shown) for increasing the rigidity of the flow path unit 31 may be provided in the second damper chamber 48. The second support portion (not shown) may be formed of the same material as the third damper plate. The second support portion (not shown) is preferably formed directly below the first support portion 70, but may be formed at a different position.

  In addition, the hole and recessed part which comprise said flow-path structure and damper chamber provided in the plates 20-30 are formed by an etching, press work, or laser processing.

  Next, the piezoelectric actuator 32 will be described. As shown in FIGS. 2 to 4, the piezoelectric actuator 32 is provided with a diaphragm 50 on the upper surface of the flow path unit 31 in the stacking direction so as to cover the plurality of pressure chambers 43. On the upper surface of the diaphragm 50, a piezoelectric layer 51 disposed so as to face the plurality of pressure chambers 43 and a plurality of individual electrodes 52 disposed on the upper surface of the piezoelectric layer 51 are provided.

  The diaphragm 50 is formed of a metal material, and is joined to the flow path unit 31 in a state of being disposed on the upper surface of the flow path unit 31 so as to cover the plurality of pressure chambers 43. The upper surface of the diaphragm 50 having conductivity also serves as a common electrode. That is, by arranging the upper surface of the diaphragm 50 on the lower surface side of the piezoelectric layer 51, a common electrode that generates an electric field in the thickness direction between the plurality of individual electrodes 52 on the upper surface of the piezoelectric layer 51 is formed. Configure. The diaphragm 50 as the common electrode is connected to the ground wiring of the driver IC 53 and is held at the ground potential.

  The piezoelectric layer 51 is made of a piezoelectric material mainly composed of lead zirconate titanate (PZT), which is a solid solution of lead titanate and lead zirconate and is a ferroelectric substance, and is formed in a flat plate shape. As shown in FIGS. 2 to 4, the piezoelectric layer 51 is continuously formed across the plurality of pressure chambers 43 on the upper surface of the vibration plate 50 in the stacking direction. A plurality of individual electrodes 52 are respectively arranged in regions on the upper surface of the piezoelectric layer 51 facing the plurality of pressure chambers 43. Each individual electrode 52 has a substantially elliptical planar shape that is slightly smaller than the pressure chamber 43, and faces the central portion of the pressure chamber 43. In addition, a plurality of contact portions 52 a are drawn from the end portions of the plurality of individual electrodes 52 along the longitudinal direction of the individual electrodes 52.

  A flexible wiring board (not shown) on which a driver IC 53 for driving the piezoelectric actuator 32 is mounted is connected to the plurality of contact portions 52a respectively corresponding to the plurality of individual electrodes 52. Then, the driver IC 53, the plurality of individual electrodes 52, and the diaphragm 50 as a common electrode are electrically connected through wiring formed on the flexible wiring board. The flexible wiring board is further connected to a main control board (not shown) of the inkjet printer 1. The driver IC 53 receives a command from the main control board, supplies a driving pulse signal to each of the plurality of individual electrodes 52, and applies a predetermined driving voltage to an active portion (not shown) of the individual electrodes. .

  Next, the operation of the piezoelectric actuator 32 when the drive pulse signal is supplied will be described. When a drive pulse signal is supplied from a driver IC 53 to a certain individual electrode 52, a predetermined active region is sandwiched between the individual electrode 52 and the diaphragm 50 as a common electrode held at the ground potential. Is applied, and an electric field in the thickness direction acts on the active portion. As a result, the active portion contracts in a plane direction orthogonal to the thickness direction, and a portion covering the pressure chamber 43 of the diaphragm 50 is deformed so as to protrude toward the pressure chamber 43 along with the contraction. At this time, since the volume in the pressure chamber 43 decreases, the ink pressure in the pressure chamber 43 rises, and ink is ejected from the nozzle 45 communicating with the pressure chamber 43.

  In order to eject ink droplets from the plurality of nozzles 45, when pressure is simultaneously applied to the ink in the plurality of pressure chambers 43 by the piezoelectric actuator 32, the common liquid is caused by propagation of residual pressure waves in the pressure chambers 43. There is a possibility that a large pressure fluctuation occurs in the chamber 41. However, as shown in FIG. 4, the first damper chamber 47 is disposed above the common liquid chamber 41, whereby the pressure fluctuation in the common liquid chamber 41 is suppressed. Furthermore, the rigidity of the pressure chamber 43 is enhanced by providing the first support portion 70 on the partition wall 25 d that partitions the first damper chamber 47 and the common liquid chamber 41. As a result, when a pressure for ejecting droplets is applied to the pressure chamber 43, the droplets can be efficiently ejected without the pressure necessary for ejecting the droplets being dispersed.

  Next, modified embodiments in which various modifications are made to the embodiment will be described. However, description of components having the same configuration as in the above embodiment will be omitted as appropriate.

<Embodiment 2>
In the first embodiment, one row (one) of the first pressure chamber row (row of the plurality of pressure chambers 43 corresponding to one common liquid chamber 41) in which the plurality of pressure chambers 43 are arranged side by side. A mode in which one damper chamber 47 is formed has been described. However, the first damper chambers 47 arranged for one row of pressure chambers are not limited to those described in the first embodiment. In the present embodiment, another embodiment will be described.

  FIG. 5 is a schematic plan view of the inkjet head 3 of the present embodiment. FIG. 6 is a partially enlarged view of part b of FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. In this embodiment, as shown in FIGS. 5 to 7, two rows of first damper chambers 47 are formed for one row of pressure chambers corresponding to one common liquid chamber. Between the first damper chambers 47 arranged in this row, a beam 80 formed by a part 24e of the first damper plate 24 and a part 25e of the second damper plate 25 is a pressure chamber row. Exists along the column. For this reason, the rigidity of the inkjet head 3 itself can be increased.

  Further, first support portions 70 are respectively formed in the two first damper chambers 47 arranged in two rows. In addition, about the shape and number of the 1st support parts 70, if the rigidity required for a pressure chamber is maintained by the 1st support part 70 to arrange | position, it can be made into arbitrary things.

  Further, in the example of FIG. 7, the configuration in which the beam 80 exists between the two first damper chambers 47 is described as an example, but the present invention is not limited thereto. As described in the first embodiment, the through hole 24a is formed in the first damper plate 24, and the spacer plate 23 having a convex portion is stacked below the row of pressure chambers at a position corresponding to the beam 80. Thus, a support portion similar to the beam 80 may be formed.

  In the example of FIGS. 5 to 7, an example in which the first damper chambers 47 arranged in two rows per one pressure chamber row is described as an example. The first damper chambers 47 arranged in a plurality of rows (three or more rows) may be formed.

<Embodiment 3>
In the first embodiment, one row (one) of the first pressure chamber row (row of the plurality of pressure chambers 43 corresponding to one common liquid chamber 41) in which the plurality of pressure chambers 43 are arranged side by side. A mode in which one damper chamber 47 is formed has been described. In the present embodiment, a mode in which one first damper chamber 47 is formed for a plurality of pressure chamber rows among the pressure chamber rows in which the plurality of pressure chambers 43 are arranged will be described. In the present embodiment, a mode in which one first damper chamber 47 is formed for all the pressure chamber rows among the pressure chamber rows in which the plurality of pressure chambers 43 are arranged will be described.

  FIG. 8 is a schematic plan view of the inkjet head 3 of the present embodiment. As shown in FIG. 8, one first damper chamber 47 is provided for every pressure chamber row. According to this embodiment, the size of the first damper chamber 47 can be increased. For this reason, since the attenuation effect of pressure fluctuation is high, the second damper chamber 48 may not be formed.

  In the example of FIG. 8, a form in which one first damper chamber 47 is provided for every pressure chamber row is shown, but the present invention is not limited to this. For example, as described in Embodiment 1 or Embodiment 2, when there are four rows of pressure chamber systems, a configuration in which two first damper chambers 47 including two rows are provided may be employed. Or you may employ | adopt the structure which provides the 1st damper chamber 47 containing 3 rows and the 1st damper chamber 47 corresponding to 1 row.

41 Common liquid chamber 43 Pressure chamber 47 1st damper chamber 48 2nd damper chamber 70 1st support part

Claims (18)

A flow path unit formed with a liquid flow path including a plurality of nozzles, a plurality of pressure chambers each communicating with each of the plurality of nozzles, and a common liquid chamber communicating with the plurality of pressure chambers; An actuator that selectively applies pressure to the liquid in the plurality of pressure chambers,
The flow path unit is formed by laminating a plurality of laminated plates,
The flow path unit further includes a first damper chamber extending so as to overlap with the plurality of pressure chambers with a direction in which the plurality of pressure chambers are arranged as a longitudinal direction when viewed from a side where the plurality of nozzles are opened. And
The first damper chamber is arranged at a height between the pressure chamber and the common liquid chamber at a height along the stacking direction in which the plurality of stacked plates are stacked,
The liquid droplet ejecting apparatus according to claim 1, wherein a first support portion is provided inside the first damper chamber.   2. The droplet ejecting apparatus according to claim 1, wherein a plurality of the first support portions are provided inside the first damper chamber. 3.   The droplet ejecting apparatus according to claim 2, wherein the plurality of first support portions are provided at the same pitch as the plurality of pressure chambers.   The droplet ejecting apparatus according to claim 2, wherein the plurality of first support portions are provided at the same pitch as the plurality of nozzles.   The region where the first support portion is formed and the region where the first support portion is not formed are continuous along the direction in which the plurality of pressure chambers are arranged inside the first damper chamber. 3. A liquid droplet ejecting apparatus according to 2.   6. The liquid droplet ejecting apparatus according to claim 1, wherein the first support portion is in contact with two opposing surfaces constituting the first damper chamber.   The liquid droplet ejection according to claim 1, wherein the first support portion is disposed so as to overlap a part of the pressure chamber when viewed from a side where the plurality of nozzles are opened. apparatus.   The droplet ejecting apparatus according to claim 1, wherein the first support portion has a shape along a longitudinal shape of the pressure chamber.   The said 1st support part is a shape which overlaps with the line | wire which connected the corner | angular part of the said pressure chamber diagonally seeing from the side in which these nozzles open. The liquid droplet ejecting apparatus described.   10. The droplet ejecting apparatus according to claim 1, wherein a width of the first damper chamber is equal to or greater than a width of the common liquid chamber in a direction perpendicular to the stacking direction.   The first support portion includes a convex portion provided on a first plate and a convex portion provided on a second plate that is lower in the stacking direction than the first plate. Item 11. The droplet ejecting device according to any one of Items 1 to 10. The first damper chamber is configured by a through hole of a third plate between the first plate and the second plate, and a recess provided in the second plate,
The liquid droplet ejecting apparatus according to claim 11, wherein the convex portion provided on the second plate is formed in a concave portion provided on the second plate.   The liquid droplet ejecting apparatus according to claim 1, wherein the flow path unit further includes a communication hole that communicates the first damper chamber and the common liquid chamber.   14. The liquid droplet ejecting apparatus according to claim 1, wherein the flow path unit further includes a second damper chamber separately from the first damper chamber.   The droplet ejecting apparatus according to claim 14, wherein the common liquid chamber is provided between the first damper chamber and the second damper chamber in the stacking direction.   The liquid droplet ejecting apparatus according to claim 14, wherein one or more second support portions are formed inside the second damper chamber.   2. The plurality of first damper chambers are provided so as to overlap with a plurality of pressure chambers in a pressure chamber array including a plurality of pressure chambers when viewed from a side where the plurality of nozzles are opened. The liquid droplet ejecting apparatus according to any one of 1 to 16.   The droplet ejecting apparatus according to claim 17, wherein a beam is formed between the plurality of first damper chambers.

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