JP5028782B2 - Droplet ejector - Google Patents

Description

  The present invention relates to a liquid droplet ejecting apparatus that ejects liquid droplets from a discharge port.

  In an inkjet head (droplet ejecting apparatus) that ejects ink from a nozzle by applying pressure to ink in the pressure chamber, a common that is generated in the pressure chamber when pressure is applied to the ink in the pressure chamber and communicates with the pressure chamber By suppressing the pressure wave propagating to the liquid chamber in the common liquid chamber and preventing the pressure wave from further propagating to other pressure chambers, it is possible to suppress variations in the ejection characteristics of the ink from the nozzles. There is something. For example, in an ink jet recording head (ink jet head) described in Patent Document 1, a plurality of pressure generating chambers (pressure chambers) communicating with nozzles communicate with an ink storage chamber (common liquid chamber) via an ink supply path. A recess is formed in a portion corresponding to the ink storage chamber of the head case. The portion overlapping the concave portion of the diaphragm acts as a damper that releases pressure fluctuation (attenuates the pressure wave) in the ink storage chamber.

Japanese Patent Laying-Open No. 2003-127354 (FIG. 3)

  However, in the ink jet head described in Patent Document 1, if the ink jet head is to be miniaturized, the head case in which the concave portion is formed needs to be miniaturized, and has a sufficient size to attenuate the pressure wave. It becomes difficult to form a portion that functions as a damper that can sufficiently attenuate the pressure wave in the head body, such as a recess cannot be formed and the area of the portion that acts as a damper of the diaphragm is reduced. The pressure wave may not be sufficiently attenuated in the common liquid chamber.

  An object of the present invention is to provide a liquid droplet ejecting apparatus that can efficiently attenuate a pressure wave in a common liquid chamber.

Means for Solving the Problems and Effects of the Invention

The liquid droplet ejecting apparatus of the present invention includes a common liquid chamber, a plurality of individual liquid passages extending from the connection port of the common liquid chamber to the discharge port through the pressure chamber, and energy application for applying discharge energy to the liquid in the pressure chamber. And a damper member that is disposed in the common liquid chamber and includes a thin film exposed on the surface, and a damper film that is in contact with the thin film and in the thickness direction and has a lower rigidity than the thin film. The common liquid chamber and the damper member extend in the same direction, and when viewed from a direction orthogonal to the bottom surface of the common liquid chamber, a part of the wall surface defining the common liquid chamber is Between the connection ports, it extends to the area overlapping the damper member toward the inside of the common liquid chamber, and when viewed from the direction orthogonal to the bottom surface of the common liquid chamber, the wall surface that defines the common liquid chamber Some of the common material is shared between the damper member and the bottom surface of the common liquid chamber. It extends to the area overlapping the damper member toward the inside of the liquid chamber, the portion of the wall surface extending to the area overlapping the damper member between the damper member and the connection port, and the damper member and the common liquid chamber The portions extending to the region overlapping with the damper member between the bottom surfaces are alternately arranged in the extending direction of the common liquid chamber.

According to this, the pressure wave generated in the pressure chamber when the discharge energy is applied to the liquid in the pressure chamber by the energy applying means and propagated to the common liquid chamber can be attenuated by the deformation of the thin film of the damper member. For this reason, it can suppress that a pressure wave propagates to the other pressure chambers connected to the common liquid chamber and crosstalk occurs. Further, since the damper member is a member separate from the members forming the common liquid chamber and the individual liquid flow path, the damper member is large enough to attenuate the pressure wave even when the droplet ejecting device is downsized. The thin film and the damper chamber can be easily formed.
Moreover, according to this, since the damper member is disposed along the extending direction of the common liquid chamber, the pressure wave can be efficiently attenuated by the damper member.
Further, according to this, since a part of the wall of the common liquid chamber exists between the damper member and the connection port, it is possible to prevent the connection port from being blocked by the damper member and obstructing the liquid flow. it can. In addition, since a part of the wall of the common liquid chamber exists between the damper member and the connection port, the damper member is prevented from reaching the wall on the connection port side of the common liquid chamber, and the damper member is always provided on both surfaces of the damper member. The liquid comes into contact, and a high damper effect is obtained.
Further, according to this, since a part of the wall of the common liquid chamber exists between the damper member and the bottom surface of the common liquid chamber, the damper member is prevented from reaching the bottom surface of the common liquid chamber, and both surfaces of the damper member are prevented. As a result, the liquid always comes into contact with each other, and a high damper effect is obtained.
Further, in the liquid droplet ejecting apparatus of the present invention, when the portion of the wall surface that extends to the region overlapping the damper member between the damper member and the connection port is viewed from the direction orthogonal to the bottom surface of the common liquid chamber. It may be arranged so as not to overlap the connection port.

  In the droplet ejecting apparatus of the present invention, the entire surface of the damper member may be covered with a thin film. According to this, since the liquid in the common liquid chamber and the thin film come into contact with each other on the entire surface of the damper member, the pressure wave in the common liquid chamber can be efficiently attenuated.

  In the droplet ejecting apparatus of the present invention, the damper chamber may be filled with gas. When the liquid in the common liquid chamber has a lower viscosity as the temperature of the ink is higher, the pressure wave is easily propagated and hardly attenuated in a high temperature environment. Therefore, the pressure wave in the common liquid chamber remains for a long time. However, according to this, the higher the temperature, the higher the pressure in the damper chamber due to the expansion of the gas in the damper chamber and the higher the damper performance of the damper chamber. Therefore, even in such a case, the pressure wave can be efficiently attenuated. it can.

  At this time, the atmospheric pressure in the damper chamber may be higher than the atmospheric pressure. According to this, since the damper performance of the damper chamber is increased, the pressure wave can be reliably attenuated.

  At this time, the gas may be air, nitrogen, oxygen, helium, or carbon dioxide. According to this, a damper member can be easily comprised by filling the gas which does not cost but is easy to obtain.

  In the liquid droplet ejecting apparatus of the present invention, the damper member may be a member in which two thin films are bonded and a damper chamber as a closed space is formed between the two thin films. . According to this, a damper member can be easily formed by bonding two thin films and forming a space serving as a damper chamber therein.

  At this time, the volume of the damper chamber may be 5% to 10% of the volume of the common liquid chamber. According to this, since the volume of the damper chamber is sufficiently large, the pressure wave in the common liquid chamber can be efficiently attenuated by the damper member.

  At this time, the thickness of the thin film may be not less than 5 μm and not more than 40 μm. According to this, since the thickness of the thin film is sufficiently thin and easily deformed, the pressure wave in the common liquid chamber can be efficiently attenuated by the damper member.

  Further, in the liquid droplet ejecting apparatus of the present invention, when the damper member is projected from the direction orthogonal to the bottom surface of the common liquid chamber, the projected area of the damper member on the bottom surface of the common liquid chamber is equal to that of the bottom surface of the common liquid chamber. It may be 70% or more of the area. According to this, since the area of the damper member is sufficiently large, the pressure wave in the common liquid chamber can be efficiently attenuated.

  In the liquid droplet ejecting apparatus of the present invention, the energy applying means includes a piezoelectric layer facing the pressure chamber and a pair of electrodes for applying an electric field to the piezoelectric layer in order to change the volume of the pressure chamber. Also good. According to this, the energy applying means can be easily configured with a simple configuration including a piezoelectric layer facing the pressure chamber and a pair of electrodes for applying an electric field to the piezoelectric layer.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. This embodiment is an example in which the present invention is applied to an inkjet head that ejects ink from nozzles.

  FIG. 1 is a schematic perspective view of an ink jet printer 1 according to the present embodiment. As shown in FIG. 1, an inkjet printer 1 includes a carriage 2 that can be moved in a scanning direction (left and right in FIG. 1), and a serial inkjet head that is configured to move together with the carriage 2 and that ejects ink onto recording paper P. (Droplet ejecting device) 3, a paper transporting roller 4 for transporting the recording paper P in the paper feeding direction (front side in FIG. 1), and the like are provided. The inkjet head 3 is configured to perform printing on the recording paper P from the nozzles 16 (see FIG. 3) disposed on the lower surface thereof while moving in the scanning direction integrally with the carriage 2. Further, the recording paper P on which printing has been performed by the ink jet head 3 is discharged by the paper transport roller 4 in the paper feeding direction.

  Next, the inkjet head 3 will be described with reference to FIGS. FIG. 2 is a plan view of the inkjet head 3 of FIG. 3 is a cross-sectional view taken along line III-III in FIG. As shown in FIGS. 2 and 3, the inkjet head 3 includes a flow path unit 31 in which ink flow paths such as a pressure chamber 10 and a manifold flow path 11 are formed, and a piezoelectric actuator disposed on the upper surface of the flow path unit 31. (Energy applying means) 32.

  As shown in FIG. 3, the flow path unit 31 is disposed in a cavity plate 21, a base plate 22, a manifold plate 23, a spacer plate 24 and a nozzle plate 25 that form an ink flow path, and a manifold flow path 11 described later. And a damper member 50. The four plates 21 to 24 excluding the nozzle plate 25 are made of a metal material such as stainless steel. In addition, ink flow paths such as the pressure chamber 10 and the manifold flow path 11 are formed in these plates 21 to 24 by etching. The nozzle plate 25 is made of a synthetic resin material such as polyimide. In the nozzle plate 25, nozzles 16 corresponding to the pressure chambers 10 on a one-to-one basis are formed by laser processing. The nozzle plate 25 may also be made of a metal material such as stainless steel, like the other four plates 21 to 24. Thereby, the warp of the flow path unit 31 due to the difference in linear expansion coefficient and the positional deviation between the flow path formed in the plates 21 to 24 and the nozzle 16 are eliminated.

  As shown in FIGS. 2 and 3, the cavity plate 21 is formed with six pressure chambers 10 arranged in two rows in the paper feeding direction (vertical direction in FIG. 2). The pressure chamber 10 is configured in a substantially oval shape that is long in the scanning direction (left-right direction in FIG. 2). In the base plate 22, a plurality of through holes 12 and 13 are formed at positions overlapping in the vicinity of both ends in the longitudinal direction of the plurality of pressure chambers 10 in plan view.

  Two manifold channels 11 extending in the paper feeding direction are formed in the manifold plate 23. One of the two manifold channels 11 overlaps substantially the left half of the three pressure chambers 10 arranged on the left side of FIG. 2 in plan view, and the other of the three pressure chambers 10 arranged on the right side of FIG. It is arranged so that it almost overlaps the right half. Ink is supplied to the manifold channel 11 from the ink supply port 9. The manifold plate 23 is formed with a communication hole 14 in a region overlapping the communication hole 13 in plan view. The manifold channel 11 is formed by closing a through-hole extending in the paper feeding direction of the manifold plate 23 from above and below with a base plate 22 and a spacer plate 24, respectively. Further, the spacer plate 24 is formed with a plurality of communication holes 15 in regions overlapping the communication holes 14 in plan view. In the nozzle plate 25, a plurality of nozzles 16 are formed in a region overlapping the plurality of communication holes 15 in plan view. The nozzle 16 can be formed by excimer laser processing when the nozzle plate 25 is made of a synthetic resin material, and a punch is used when the nozzle plate 25 is made of a metal material. It can be formed by press working. The ink inlet 9 is formed at one end (lower side in FIG. 2) in the paper feeding direction so as to avoid the region where the piezoelectric actuator 32 of the flow path unit 31 is disposed. Here, one ink inlet 9 is provided for each manifold channel 11.

  The damper member 50 is disposed in the manifold channel 11 and extends in the paper feed direction that is the direction in which the manifold channel 11 extends. The damper member 50 is for attenuating the pressure wave in the manifold channel 11 and has two metal thin plates 51 (thin film) having a thickness of about 5 to 40 μm, more preferably about 5 to 15 μm. ) Are joined to each other by an adhesive 52. A space enclosed by the two thin plates 51 and the adhesive 52 (closed space) is a damper chamber 53. The damper chamber 53 is filled with air, and the rigidity of the damper chamber 53 is lower than the rigidity of the thin plate 51. In the damper member 50, the area of the thin plate 51 (projected area on the bottom surface of the manifold channel 11) is 70% or more of the bottom area of the manifold channel 11. The volume of the damper chamber 50 is about 5 to 10% of the volume of the manifold channel 11.

  The damper member 50 is produced by bonding the peripheral portions of the two thin plates 51 with the adhesive 52 under a temperature lower than the usage environment. As a result, the atmospheric pressure in the damper chamber 53 rises and becomes higher than the atmospheric pressure under the usage environment, and the damper performance (attenuation characteristics) against the pressure wave of the damper member 50 is improved. Furthermore, the higher the temperature of the air, the larger the volume of the damper chamber 53 due to the expansion of the air, and the higher the air pressure in the damper chamber 53, and the damper performance as the damper member 50 is further improved.

  The flow path unit 31 joins the three plates 21 to 23 and the two plates 24 and 25 separately, and joins the three plates 21 to 23 out of the five plates 21 to 25. After the damper member 50 is inserted into the manifold channel 11 formed by the above, the three plates 21 to 23 joined and the two plates 24 and 25 joined are joined together. Is formed.

  In such a flow path unit 31, as shown in FIG. 3, the manifold flow path 11 communicates with the pressure chamber 10 through the communication hole 12, and the pressure chamber 10 communicates with the communication holes 13, 14, 15. Via the nozzle 16. As described above, the flow path unit 31 is formed with a plurality of individual ink flow paths from the outlet (connection port) of the manifold flow path 11 to the nozzle 16 through the pressure chamber 10.

  As shown in FIG. 3, the piezoelectric actuator 32 includes a vibration plate 40 disposed on the upper surface of the flow path unit 31, a piezoelectric layer 41 disposed on the upper surface of the vibration plate 40, and a plurality of pressures on the upper surface of the piezoelectric layer 41. And a plurality of individual electrodes 42 formed corresponding to the chamber 10.

  The diaphragm 40 is made of a substantially rectangular metal material in plan view, and is made of, for example, an iron-based alloy such as stainless steel, a copper-based alloy, a nickel-based alloy, or a titanium-based alloy. The vibration plate 40 is disposed on the upper surface of the cavity plate 21 so as to cover the plurality of pressure chambers 10 and is joined to the cavity plate 21. Further, the diaphragm 40 made of metal has conductivity, and also serves as a common electrode for applying an electric field to a portion sandwiched between the individual electrodes 42 in the piezoelectric layer 41 and is always kept at the ground potential. ing. When the diaphragm 40 is formed of an insulating member such as ceramic, a common electrode may be provided on the upper surface of the diaphragm 40, and the common electrode, the individual electrode 42, and the like may be provided as in the present embodiment. An electric field can be applied to the piezoelectric layer 41 sandwiched between.

  On the upper surface of the diaphragm 40, a piezoelectric layer 41 made of a piezoelectric material mainly composed of lead gluconate titanate (PZT), which is a solid solution of lead titanate and lead gluconate and has ferroelectricity, is formed. . The piezoelectric layer 41 is continuously formed in a sheet shape across the plurality of pressure chambers 10. The piezoelectric layer 41 can be formed, for example, by an aerosol deposition method (AD method) in which particles of very small piezoelectric material are sprayed at a high speed to collide against the substrate and deposited on the surface of the substrate. The piezoelectric layer 41 can also be formed by a sputtering method, a chemical vapor deposition method (CVD method), a sol-gel method, a hydrothermal synthesis method, or the like. Alternatively, a piezoelectric sheet obtained by firing a PZT green sheet may be cut into a predetermined size and attached to the upper surface of the vibration plate 41.

  On the upper surface of the piezoelectric layer 41, a plurality of individual electrodes 42 having a substantially oval shape that is slightly smaller than the pressure chamber 10 are formed in a region overlapping the pressure chamber 10 in plan view. The individual electrode 42 is made of a conductive material such as gold, copper, silver, palladium, platinum, or titanium. One end of the individual electrode 42 in the longitudinal direction extends to a region that does not overlap the pressure chamber 10 in plan view in the longitudinal direction of the individual electrode 42, and this portion serves as a contact 42 a. The individual electrodes 42 and the contacts 42a can be formed by methods such as screen printing, sputtering, and vapor deposition.

  A flexible printed circuit board (FPC) (not shown) is formed on the upper surface of the piezoelectric actuator 32, and the contact 42a and the signal line of the FPC are electrically connected. The FPC is connected to a driver IC (not shown), and the potential of the individual electrode 42 is controlled by the driver IC via the FPC. The FPC ground line is also connected to the common electrode, and is held at the ground potential.

  Next, the operation of the piezoelectric actuator 32 will be described. When a predetermined potential is selectively applied to the individual electrode 42 by the driver IC, a potential difference is generated between the individual electrode 42 to which the predetermined potential of the piezoelectric layer 41 is applied and the diaphragm 40 as a common electrode, An electric field in the thickness direction acts on a portion of the piezoelectric layer 41 sandwiched between them. When the polarization direction of the piezoelectric layer 41 is the same as the thickness direction, the piezoelectric layer 41 contracts in the horizontal direction perpendicular to the thickness direction. In contrast to the contraction of the piezoelectric layer 41, the diaphragm 40 functions to restrict the contraction. At this time, the piezoelectric actuator 32 is deformed so that the portion corresponding to the selected individual electrode 42 is convex toward the pressure chamber 10. As a result, the volume of the pressure chamber 10 is reduced and the pressure of the ink in the pressure chamber 10 is increased, so that ink is ejected from the nozzle 16 communicating with the pressure chamber 10.

  A pressure wave is generated in the pressure chamber 10 due to an increase in pressure at this time, and this pressure wave propagates from the pressure chamber 10 to the manifold channel 11. In the manifold channel 11, the damper member 50 attenuates this pressure wave by the deformation of the thin plate 51. Accordingly, crosstalk in which the pressure wave propagated to the manifold channel 11 further propagates to the other pressure chambers 10 and the ink ejection characteristics from the nozzles 16 vary is suppressed. Here, the ink ejection characteristics refer to the ejection speed of the ink droplets and the volume of the ejected ink droplets.

  Here, the viscosity of the ink in the manifold channel 11 decreases as the temperature increases, and the pressure wave is less likely to attenuate. However, even if a large pressure wave propagates to the manifold channel 11, Since the air is filled with air, the air expands to increase the volume of the damper chamber 53 and increase the pressure in the damper chamber 53, and the damper performance of the damper member 50 increases. Therefore, the pressure wave can be efficiently attenuated even in a high temperature environment. Furthermore, since the damper member 50 is configured in advance at a lower temperature even in a low temperature environment, a gap that does not hinder the deformation of each thin plate 51 due to the pressure wave is secured as the damper chamber 53. For this reason, at least between the adjacent pressure chambers 10 does not cause crosstalk that affects ink ejection characteristics.

  According to the embodiment described above, since the damper member 50 is provided in the manifold flow path 11, the pressure wave propagated from the pressure chamber 10 to the manifold flow path 11 is transmitted in the manifold flow path 11 to the damper member 50. It can be attenuated by deformation of the thin plate 51. Accordingly, it is possible to suppress crosstalk in which the pressure wave propagates from the manifold channel 11 to another pressure chamber 10 and the ink ejection characteristics from the nozzles 16 change. Furthermore, since the damper member 50 is a separate member from the plates 21 to 25 that form the ink flow path, even when the flow path unit 31 is downsized, the damper member 50 is large enough to attenuate the pressure wave. The thin plate 51 and the damper chamber 53 can be easily formed.

  Further, since the damper member 50 is formed by bonding the peripheral portions of the two thin plates 51 with the adhesive 52 and forming the damper chamber 53 between the two thin plates 51, the entire thin plate 51 is the manifold channel 11. It is in contact with the ink inside and can efficiently attenuate the pressure wave.

  Moreover, since the damper chamber 53 is filled with air having a pressure higher than the atmospheric pressure and the damper performance of the damper member 50 is increased, the pressure wave can be efficiently attenuated. Furthermore, under a high temperature environment, the pressure in the damper chamber 53 is further increased, and the damper performance of the damper member 50 is improved. For this reason, even if the pressure wave is less likely to be attenuated due to a decrease in the viscosity of the ink in a high temperature environment, the pressure wave can be efficiently attenuated even when a large pressure wave propagates to the manifold channel 11. In addition, the damper member 50 can be easily configured by filling the damper chamber 53 with air that is inexpensive and easy to obtain.

  Moreover, since the volume of the damper chamber 53 is about 5 to 10% of the volume of the manifold channel 11 and has a sufficiently large volume, the pressure wave can be attenuated efficiently.

  Moreover, since the thickness of the thin plate 51 of the damper member 50 is 5-40 micrometers, the thin plate 51 is easy to deform | transform and it can attenuate a pressure wave efficiently.

  Moreover, since the area of the damper member 50 is 70% or more of the bottom area of the manifold channel 11 in plan view and has a sufficiently large area, the pressure wave can be attenuated efficiently.

  Next, modified examples in which various changes are made to the present embodiment will be described. However, the same reference numerals are given to those having the same configuration as the present embodiment, and the description thereof is omitted as appropriate.

  In one modified example, as shown in FIGS. 4 and 5, three protruding portions 63 and three protruding portions 64 are formed on both side walls of the manifold channel 11 (modified example 1). 4 is an enlarged plan view of a part of the manifold flow path 11 of the inkjet head according to the first modification, and FIG. 5 is a cross-sectional view taken along the line V-V in FIG. However, in FIG. 4, illustration of the upper part from the base plate 22 is omitted, and the positions of the pressure chamber 10 and the communication holes 12 and 13 are indicated by two-dot chain lines. The protrusions 63 and 64 are formed on the first manifold plate 61 and the second manifold plate 62 by half-etching or the like, respectively, and the protrusions 63 and 64 are respectively in plan view above and below the damper member 50. In this way, it extends alternately from the both side walls of the manifold channel 11 to the inside of the manifold channel 11 at a predetermined interval so as to overlap a part of the damper member 50.

  In this case, since the protruding portion 63 is formed, the damper member 50 does not move above the protruding portion 63. That is, the damper member 50 does not reach the upper surface of the manifold channel 11. Therefore, it is possible to prevent the communication hole 12 from being blocked by the damper member 50 and stopping the ink flow. Further, since the protrusions 63 and 64 are formed, the surface of the damper member 50 does not contact the bottom surface or the top surface of the manifold channel 11. For this reason, both of the two thin plates 51 of the damper member 50 are always in contact with the ink, and the pressure wave can be efficiently attenuated by the deformation of the two thin plates 51 of the damper member 50.

  Further, in this case, as shown in FIG. 5, the first manifold plate 61 is formed with the upper part of the manifold channel 11, and the second manifold plate 62 is formed with the lower part of the manifold channel 11, The manifold channel 11 is formed by joining the first manifold plate 61 and the second manifold plate 62. Further, as corresponding to the communication hole 14 of the embodiment, the first manifold plate 61 is formed with a communication hole 65 communicating with the communication hole 13, and the second manifold plate 62 is formed with the communication hole 65 and the communication hole 15. A communication hole 66 that communicates is formed. In addition, although the protrusion part 63 and the protrusion part 64 are formed in the modification 1, from a viewpoint of attenuation | damping of an unnecessary pressure wave, only one of these may be formed.

  In another modification, as shown in FIGS. 6 and 7, the first damper support member 71 is disposed above the damper member 50 of the manifold channel 11 so as to overlap a part of the damper member 50 in plan view. A second damper support member 72 is formed below the damper member 50 of the manifold channel 11 so as to overlap a part of the damper member 50 in a plan view (Modification 2). 6 is an enlarged plan view of a part of the manifold flow path 11 of the inkjet head according to the second modification, and FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. However, in FIG. 6, illustration of the upper part from the baseplate 22 is abbreviate | omitted, and the position of the pressure chamber 10 and the communicating holes 12 and 13 is shown with the dashed-two dotted line. In this case, the first damper support member 71 extends the manifold channel 11 above one end (the right end of the manifold channel 11 in FIG. 6) in the width direction of the manifold channel 11 (the left-right direction in FIG. 6). The both ends of the extending direction extend inward in the width direction of the manifold channel 11 and are longer than half of the width of the manifold channel 11 while extending in the existing direction (vertical direction in FIG. 6). On the other hand, the second damper support member 72 extends in the extending direction of the manifold channel 11 below the other end in the width direction of the manifold channel 11 (the left end of the manifold channel 11 in FIG. 6). Are extended longer than the half of the width of the manifold channel 11 inside the manifold channel 11 in the width direction. Here, the portion of the first damper support member 71 extending in the vertical direction in FIG. 6 extends to the inside of the manifold channel 11 and partially closes the opening of the communication hole 12. That is, the extending portion also functions as a throttle portion that regulates the flow rate of ink from the manifold channel 11 to the pressure chamber 10.

  In this case, since the first damper support member 71 is formed, the damper member 50 does not move higher than the first damper support member 71. For this reason, it is possible to prevent the communication hole 12 from being blocked by the damper member 50 and stopping the ink flow. Further, since the first damper support member 71 and the second damper support member 72 are formed, none of the two thin plates 51 of the damper member 50 contacts the bottom surface or the top surface of the manifold channel 11. Therefore, both of the two thin plates 51 of the damper member 50 are always in contact with the ink, and the pressure wave can be efficiently attenuated by the deformation of the two thin plates 51. In the second modification, the first damper support member 71 and the second damper support member 72 are provided, but from the viewpoint of unnecessary pressure wave attenuation, either one of them may be provided. Good.

  Further, the damper chamber 53 of the damper member 50 may be filled with a relatively easily available gas other than air, such as nitrogen, oxygen, helium, carbon dioxide, instead of air. Further, instead of gas, a liquid may be enclosed in the damper chamber 53 as long as the thin plate 51 is not eroded or altered. Alternatively, although depending on the required damper performance, a porous resin having pores may be enclosed in the damper chamber 53.

  Further, the damper member is not limited to a member in which two flat thin plates are bonded together, and may be a member in which a space filled with air is formed inside a curved thin film, for example. . As an example of creating such a space, if the two thin plates 51 are directly joined with the adhesive 52, each of the two thin plates 51 is joined by a pressure wave between the two thin plates 51. It is preferable that the thin plate 51 is preliminarily molded so that a gap that allows the thin plate 51 to freely deform each other is formed. Further, if the thin plate 51 is not molded in advance, a spacer member that generates a similar gap may be interposed at the joint between the two thin plates 51.

  Further, the thin film of the damper member 50 is not limited to the material as long as it is a flexible member, and may be a resin film such as polyimide that has been subjected to a treatment for improving gas permeability resistance. Also in this case, the thickness is preferably about 5 to 40 μm.

  In addition, from the viewpoint of combining attenuation of pressure waves and good ink supply, a gap is formed between the damper member 50 and the communication hole 12 such as at least the protrusion 63 and the first damper support member 71. It is preferable to have a regulating member that can be used. In addition, a damping member that can create a gap between the damper member 50 and the bottom of the manifold channel 11, such as the protrusion 64 and the second damper support member 72, can further reduce the damping force against pressure waves. Will improve.

  Also at this time, even if the rigidity of the peripheral portion of the damper member 50 is increased so as to extend into the manifold channel 11 as a common liquid chamber, the flexible member (thin plate 51) is deformed well and the peripheral portion is deformed. In order to avoid this, the two thin plates 51 may be joined via a spacer member as a frame member having a predetermined rigidity, regardless of whether or not the thin plate 51 is molded in advance.

  That is, in a liquid droplet ejecting apparatus that ejects liquid from an ejection port, a common liquid chamber that temporarily stores the liquid, and a plurality of individual liquid flow paths that extend from the connection port of the common liquid chamber to the ejection port via the pressure chamber And an energy applying means for applying discharge energy to the liquid in the pressure chamber, and a damper member installed in the common liquid chamber so as to be opposed to the connection port and movable in a direction to be separated from and connected to the connection port. The member is exposed on the surface and faces the connection port, the flexible member, the frame member that supports the peripheral edge of the flexible member, and the frame member is surrounded by the flexible member and its thickness. Between the damper member and the wall surface when viewed from the direction perpendicular to the wall surface of the common liquid chamber in which the connection port is formed. Placed so as to overlap the frame member It may have a regulating member.

  As a result, the damper member 50 is supported by the restricting member at the portion of the frame member having high rigidity, so that the damper member 50 is not bent or detached from the restricting member in the manifold channel 11. That is, the damper member 50 does not block the flow path, and the desired damper performance can be exhibited.

  Further, the common liquid chamber is composed of at least a wall surface where the connection port is opened and an opposing wall surface facing in parallel with the wall surface, and when viewed from a direction orthogonal to the wall surface, between the damper member and the facing wall surface. And another restricting member arranged so as to overlap the frame member.

  As a result, the damper member 50 is positioned at substantially the center of the manifold channel 11 in the stacking direction, and the upper and lower surfaces thereof are in contact with the ink in the channel, so that the damper performance is improved accordingly.

  The piezoelectric actuator 32 used in the present embodiment is composed of the piezoelectric layer 41 sandwiched between the pair of electrodes (common electrode and individual electrode) on the vibration plate 40. The configuration of the piezoelectric actuator 32 is not limited to this.

  For example, as shown in FIG. 8A, a plurality of layers sandwiched between a pair of electrodes may be laminated on the upper surface of the cavity plate 21. That is, the piezoelectric layer 241 in which the common electrode 246 is formed on the surface opposite to the pressure chamber 10 and the individual electrode 244 disposed on the upper surface and facing the pressure chamber 10 on the surface opposite to the pressure chamber 10. Each of the piezoelectric layers 242 formed with a single set may have a configuration in which a plurality of sets are stacked. Here, three sets are laminated in order, and the piezoelectric actuator 280 is formed by laminating the piezoelectric layer 241 and two piezoelectric layers 243 on which no electrode is formed on the laminated body. Each of the piezoelectric layers 241 and 242 is polarized in the stacking direction. In the piezoelectric actuator 280 having this configuration, when a predetermined voltage is applied between the common electrode 246 and the individual electrode 244, the piezoelectric layers 241 and 242 sandwiched between both electrodes expand and contract in the stacking direction, thereby corresponding pressure chambers 10. The volume of changes. For the FPC, the common 246 and the individual electrodes 244 may be electrically led through through holes to the uppermost layer and connected in the uppermost layer.

  Further, as shown in FIG. 8B, a configuration in which a plurality of piezoelectric layers 341 in which a common liquid chamber 346 and individual electrodes 344 are formed on the surface opposite to the pressure chamber 10 on the upper surface of the cavity plate 21 is laminated. You may have. Here, a piezoelectric actuator 380 is formed from five piezoelectric layers 341 and an uppermost piezoelectric layer 342 on which no electrode is formed. Each individual electrode 344 is formed to face the pressure chamber 10, and each common electrode 346 is arranged to face a digit that defines the pressure chamber 10. In the piezoelectric actuator having this configuration, when a predetermined voltage is applied between the common liquid chamber 346 and the individual electrode 344, the piezoelectric layer 341 sandwiched between the selected individual electrode 344 and the two common electrodes 346 adjacent thereto. Cause thickness slip deformation. As a result, the portion of the piezoelectric actuator 380 facing the pressure chamber 10 is displaced so as to change the volume of the pressure chamber 10. For the FPC, the common electrode 346 and the individual electrode 344 may be electrically led to the uppermost layer through holes and connected on the surface of the uppermost layer.

  In the present embodiment, an example in which the present invention is applied to an ink jet head has been shown. In addition to this, liquids other than ink such as reagents, biological solutions, wiring material solutions, electronic material solutions, refrigerants, and fuels are ejected. It is also possible to apply to a droplet ejecting apparatus.

1 is a schematic perspective view of an ink jet printer according to an embodiment of the present invention. It is a top view of the inkjet head of FIG. It is the III-III sectional view taken on the line of FIG. 10 is an enlarged plan view of a part of a manifold of an ink jet head according to Modification 1. FIG. It is the VV sectional view taken on the line of FIG. 10 is an enlarged plan view of a part of a manifold of an inkjet head according to a second modification. It is the VII-VII sectional view taken on the line of FIG. It is sectional drawing which shows the example of another form of the piezoelectric actuator used.

Explanation of symbols

3 Inkjet Head 10 Pressure Chamber 11 Manifold Channel 16 Nozzle 31 Channel Unit 32 Piezoelectric Actuator 50 Damper Member 51 Thin Plate 53 Damper Chamber 63, 64 Projection 71 First Damper Support Member 72 Second Damper Support Member

Claims (11)

A common liquid chamber;
A plurality of individual liquid flow paths from the connection port with the common liquid chamber to the discharge port through the pressure chamber;
Energy applying means for applying discharge energy to the liquid in the pressure chamber;
A thin film exposed on the surface, and a damper member including a thin film and a damper chamber that is in contact with the thin film in the thickness direction and has a rigidity lower than that of the thin film. Prepared ,
The common liquid chamber and the damper member extend in the same direction;
When viewed from a direction orthogonal to the bottom surface of the common liquid chamber, a part of the wall surface defining the common liquid chamber is directed toward the inside of the common liquid chamber between the damper member and the connection port. Extending to the area overlapping the damper member,
When viewed from a direction orthogonal to the bottom surface of the common liquid chamber, a part of the wall surface defining the common liquid chamber is located between the damper member and the bottom surface of the common liquid chamber, and inside the common liquid chamber. Extending to the area overlapping the damper member,
A portion of the wall surface that extends to a region that overlaps the damper member between the damper member and the connection port, and a region that overlaps the damper member between the damper member and the bottom surface of the common liquid chamber. The liquid droplet ejecting apparatus , wherein the existing portions are alternately arranged in the extending direction of the common liquid chamber .   A portion of the wall surface that extends to a region overlapping the damper member between the damper member and the connection port does not overlap the connection port when viewed from a direction orthogonal to the bottom surface of the common liquid chamber. The droplet ejecting apparatus according to claim 1, wherein the droplet ejecting apparatus is arranged as described above. The liquid-droplet jetting apparatus according to claim 1 or 2, characterized in that the entire surface of said damper member is covered with the thin film. The droplet ejecting apparatus according to claim 1, wherein the damper chamber is filled with a gas. The liquid droplet ejecting apparatus according to claim 4 , wherein an atmospheric pressure in the damper chamber is higher than an atmospheric pressure. The droplet ejecting apparatus according to claim 4 , wherein the gas is air, nitrogen, oxygen, helium, or carbon dioxide. The damper member has two said thin film is bonded, of claims 1 to 6, characterized in that said damper chamber as a closed space between these two of the thin film is formed Liquid regular injection device given in any 1 paragraph. The droplet ejecting apparatus according to claim 1, wherein a volume of the damper chamber is 5% or more and 10% or less of a volume of the common liquid chamber. The droplet ejecting apparatus according to claim 1, wherein the thin film has a thickness of 5 μm or more and 40 μm or less. When the damper member is projected from a direction orthogonal to the bottom surface of the common liquid chamber, the projected area of the damper member onto the bottom surface of the common liquid chamber is 70% or more of the area of the bottom surface of the common liquid chamber. The liquid droplet ejecting apparatus according to claim 1, wherein Said energy application means, according to claim 1, wherein the piezoelectric layer facing the pressure chamber, that it contains a pair of electrodes for applying an electric field to the piezoelectric layer in order to change the volume of the pressure chamber The droplet ejecting apparatus according to any one of 10 to 10 .

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