JP2018094867A - Liquid jet head and liquid jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid jet head which can reduce a pressure wave leaking from a pressure chamber to a liquid passage without reducing a reflection rate of the pressure wave in a connection portion between the liquid passage and the pressure chamber, and to provide a liquid jet recording device.SOLUTION: An inkjet head 4 has: ink introduction passages 62 to which a liquid is supplied; multiple pressure chambers 60 respectively connected with the ink introduction passages 62 and to which an ink flows; a nozzle plate 43 which is disposed facing the pressure chambers 60 and is formed with nozzles 43A; an actuator plate 40 which varies the volumetric capacity of the pressure chambers 60 to jet the ink in the pressure chambers 60 from the nozzles 43A as ink droplets; and filters 64, each of which is provided at the ink introduction passage 62 side spaced away from a connection portion between the ink introduction passage 62 and the pressure chamber 60 and through which the ink passes. Further, a printer has: the inkjet head 4; ink supply means which supplies the ink to the inkjet head 4; and scanning means which scans the ink jet head 4 in a direction intersecting with a recording medium transport direction.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a liquid jet head and a liquid jet recording apparatus having the liquid jet head.

  2. Description of the Related Art Conventionally, an ink jet type liquid ejecting head that draws an image, characters, or the like by ejecting droplet-like ink from a nozzle toward a recording medium has been used. Further, as an ink jet type liquid ejecting head, ink is caused to flow from the nozzle to the pressure chamber by causing the ink to flow into the pressure chamber and changing the volume of the pressure chamber by a piezoelectric actuator or the like to generate a pressure wave in the ink in the pressure chamber. A so-called piezo-type liquid jet head for jetting is known.

  In this piezo-type liquid ejecting head, the pressure wave generated in the pressure chamber is reflected at the connection portion between the pressure chamber at the open end and the liquid flow path, and almost returns to the pressure chamber. May leak into the liquid flow path without being reflected at the open end. In order to reduce the pressure wave leaking into the liquid flow path, for example, Patent Document 1 discloses a pumping chamber (pressure chamber) or a connection portion between a pumping chamber (pressure chamber) and a nozzle flow path (liquid flow path). The structure which provides the filter which absorbs a pressure wave is disclosed.

JP 2010-76453 A

  When the filter is provided in the pressure chamber, the pressure wave in the pressure chamber is absorbed by the filter, and therefore, the energy efficiency of the ejection operation may be deteriorated particularly when performing the ink ejection operation a plurality of times in a short time. In addition, when the filter is provided at the connection portion between the pressure chamber and the liquid flow path, the opening area of the connection portion (opening end) of the pressure chamber is narrowed by the filter. There is a possibility that the reflectance of the pressure wave is reduced.

  In view of the above fact, the present invention can reduce the pressure wave leaking from the pressure chamber into the liquid channel without reducing the reflectance of the pressure wave at the connection portion between the liquid channel and the pressure chamber. An object is to provide an ejection head and a liquid ejection recording apparatus.

  The liquid ejecting head according to claim 1, wherein a liquid channel to which a liquid is supplied, a plurality of pressure chambers connected to the liquid channel and into which the liquid flows, and a nozzle that is disposed facing the pressure chamber are formed A nozzle plate, an actuator for changing the volume of the pressure chamber to eject the liquid in the pressure chamber as droplets from the nozzle, and the liquid flow away from a connection portion between the liquid flow path and the pressure chamber. And a filter that is provided on the road side and through which the liquid passes.

  By changing the volume of the pressure chamber with the actuator, the liquid in the pressure chamber is ejected as droplets from the nozzle. At this time, the pressure wave generated in the pressure chamber travels to the liquid flow path side and is mostly reflected at the connection portion between the liquid flow path and the pressure chamber and returns to the pressure chamber. It leaks into the liquid flow path without being reflected.

  Here, according to the above configuration, the filter through which the liquid passes is provided on the side of the liquid flow channel away from the connection portion between the liquid flow channel and the pressure chamber. For this reason, the pressure wave leaked from the pressure chamber into the liquid channel can be reduced by the filter, and the ejection behavior of the liquid ejected from the nozzles of the other pressure chambers through the liquid channel can be reduced. Disturbing so-called crosstalk can be suppressed.

  In addition, since the filter is provided at a position away from the connection portion between the liquid flow path and the pressure chamber, it is possible to prevent the opening area of the connection portion between the pressure chamber from being narrowed by the filter. It can suppress that the reflectance of the pressure wave in a connection part reduces.

  The liquid ejecting head according to claim 2 is the liquid ejecting head according to claim 1, wherein the filter is provided on an extension line in a longitudinal direction of the pressure chamber, and the connection portion of the pressure chamber is provided. An opening end correction distance derived from the opening area is provided away from the connection portion toward the liquid channel.

  According to the said structure, the pressure wave which leaked from the connection part of a liquid flow path and a pressure chamber can be efficiently absorbed and reduced by a filter by providing a filter on the extension line | wire of the longitudinal direction of a pressure chamber. In addition, the filter reduces the reflectance of the pressure wave at the connection part by providing the filter farther from the connection part of the pressure chamber to the liquid channel side than the opening end correction distance derived from the opening area of the connection part of the pressure chamber. It can be suppressed more.

  A liquid ejecting head according to a third aspect is the liquid ejecting head according to the first or second aspect, wherein the height of the filter is higher than the height of the connecting portion of the pressure chamber.

  According to the above configuration, since the height of the filter is higher than the height of the connection portion of the pressure chamber, the height of the filter is less than the height of the connection portion of the pressure chamber, so that The leaked pressure wave can be further reduced.

  A liquid ejecting head according to a fourth aspect is the liquid ejecting head according to any one of the first to third aspects, wherein the filters protrude from the inner wall surface of the liquid flow channel at a distance from each other. It is composed of a plurality of protrusions.

  According to the above configuration, since the filter is configured by a plurality of projections spaced from each other, it is possible to reduce pressure waves leaking from the pressure chamber into the liquid flow path while allowing the liquid to pass therethrough. it can. In addition, by forming the filter with a plurality of protrusions, the filter can be easily manufactured and installed as compared with a configuration in which the filter is formed with a plurality of holes provided in a wall body or the like.

  The liquid ejecting head according to claim 5 is the liquid ejecting head according to claim 4, wherein the pressure chamber is provided in parallel on both sides of the liquid flow path, and the liquid flow path The connecting portion with the pressure chamber is displaced in a direction along the liquid flow path, and the protrusion is along a virtual line that connects the walls constituting the pressure chamber facing each other across the liquid flow path. Are lined up.

  According to the above configuration, since the protrusion is provided along the imaginary line that connects the walls of the pressure chambers facing each other across the liquid flow path, the pressure waves leaking from the pressure chamber into the liquid flow path are arranged in parallel. Disturbing the ejection behavior of the liquid in the other pressure chamber can be suppressed by the protrusion.

  A liquid jet recording apparatus according to a sixth aspect records the liquid jet head according to any one of the first to fifth aspects, a liquid supply unit that supplies a liquid to the liquid jet head, and the liquid jet head. And a scanning unit that scans in a direction that intersects the conveyance direction of the medium.

  By supplying liquid from the liquid supply means of the liquid jet recording apparatus to the liquid jet head, and scanning the liquid jet head in a direction intersecting with the conveyance direction of the recording medium by the scanning means, jetting droplets onto the recording medium, An image can be formed on a recording medium. Here, according to the above configuration, since the liquid ejecting head includes the configuration according to any one of claims 1 to 5, variations in ejection speed and ejection volume of the droplet ejected from the nozzle are suppressed. can do.

  According to the present invention, the pressure wave leaking from the pressure chamber into the liquid channel can be reduced without reducing the reflectance of the pressure wave at the connection portion between the liquid channel and the pressure chamber.

1 is a perspective view showing an ink jet printer as a liquid jet recording apparatus according to a first embodiment. FIG. 2 is a perspective view illustrating an ink jet head of an ink jet printer as a liquid ejecting head according to the first embodiment. It is a perspective view which shows the head chip of an inkjet head. FIG. 4 is an exploded perspective view of the head chip in FIG. 3. FIG. 5 is an enlarged exploded perspective view illustrating a state where an actuator plate and a cover plate of the head chip in FIG. 4 are disassembled. It is the sectional view on the AA line in FIG. FIG. 6 is a perspective view showing a head chip of an ink jet head as a liquid jet head according to a second embodiment. It is the BB sectional view taken on the line in FIG. FIG. 9 is an enlarged plan view corresponding to the cross-sectional view taken along the line CC of FIG. 8 showing a modification of the head chip of the second embodiment. (A), (B) is an enlarged plan view equivalent to the DD sectional view of Drawing 8 showing other modifications of the head chip of a 2nd embodiment.

<First Embodiment>
Hereinafter, a liquid jet head and a liquid jet recording apparatus according to a first embodiment of the invention will be described with reference to FIGS. In the following embodiments, an ink jet printer (hereinafter referred to as “printer”) that performs recording on a recording medium using ink as a liquid will be described as an example of a liquid jet recording apparatus including a liquid jet head.

(Printer)
As shown in FIG. 1, a printer 1 includes a pair of conveying units 2 and 3 that convey a recording medium S such as recording paper, and an ink jet head as a liquid ejecting head that ejects ink (liquid) (not shown) to the recording medium S. 4 is provided.

  The printer 1 includes an ink supply unit 5 as a liquid supply unit that supplies ink to the inkjet head 4, a scanning unit 6 that scans the inkjet head 4 in a scanning direction X that intersects the transport direction Y of the recording medium S, It has. In the present embodiment, the direction perpendicular to the two directions of the transport direction Y and the scanning direction X is defined as the vertical direction Z.

  The pair of conveying means 2 and 3 are arranged with a gap in the conveying direction Y, one conveying means 2 is located upstream in the conveying direction Y, and the other conveying means 3 is downstream in the conveying direction Y. Is located.

  The conveying means 2 and 3 are arranged parallel to the grid rollers 2A and 3A extending in the scanning direction X and the grid rollers 2A and 3A, and printing is performed between the grid rollers 2A and 3A. Pinch rollers 2B and 3B that sandwich the medium S and drive mechanisms such as a motor (not shown) that rotate the grid rollers 2A and 3A around their axes are provided. The recording medium S can be transported in the direction of arrow A along the transport direction Y by rotating the grid rollers 2A and 3A of the pair of transport means 2 and 3.

  The ink supply unit 5 includes an ink tank 10 that contains ink, and an ink pipe 11 that connects the ink tank 10 and the inkjet head 4. In this embodiment, for example, ink tanks 10Y, 10M, 10C, and 10B each containing four colors of ink of yellow (Y), magenta (M), cyan (C), and black (B) are arranged in the transport direction Y. Is arranged in. The ink pipe 11 is a flexible hose having flexibility, for example, and can follow the operation (movement) of the carriage 16 that supports the inkjet head 4.

  The scanning means 6 extends in the scanning direction X, and is paired with a pair of guide rails 15 arranged in parallel with each other in the transport direction Y, and a carriage 16 disposed so as to be movable along the pair of guide rails 15; And a drive mechanism 17 that moves the carriage 16 in the scanning direction X.

  The drive mechanism 17 is disposed between the pair of guide rails 15, is wound between the pair of pulleys 18 disposed at a distance in the scanning direction X, and moved in the scanning direction X. An endless belt 19 and a drive motor 20 that rotationally drives one pulley 18 are provided.

  The carriage 16 is connected to an endless belt 19 and is movable in the scanning direction X along with the movement of the endless belt 19 by the rotational drive of one pulley 18. A plurality of inkjet heads 4 are mounted on the carriage 16 in a state of being aligned in the scanning direction X.

  In the present embodiment, four inkjet heads 4 that respectively eject yellow (Y), magenta (M), cyan (C), and black (B) inks, that is, inkjet heads 4Y, 4M, 4C, and 4B are mounted. ing.

(Inkjet head)
As shown in FIG. 2, the inkjet head 4 includes a fixed plate 25 fixed to the carriage 16 shown in FIG. 1, and a head chip 26 fixed on the fixed plate 25. Further, an ink supply unit 27 that supplies the ink supplied from the ink supply unit 5 shown in FIG. 1 to a common ink chamber 41A (described later) of the head chip 26, a control unit 28 that applies a drive voltage to the head chip 26, and It has.

  The inkjet head 4 ejects ink of each color with a predetermined ejection amount by applying a driving voltage. At this time, as shown in FIG. 1, the inkjet head 4 is moved in the scanning direction X by the scanning unit 6, so that recording can be performed in a predetermined range on the recording medium S. By repeating this scanning, it is possible to perform recording on the entire recording medium S while the recording medium S is intermittently conveyed in the conveying direction Y by the conveying means 2 and 3.

  As shown in FIG. 2, a base plate 30 made of metal such as aluminum is fixed to the fixed plate 25 in an upright direction Z, and ink is placed in a common ink chamber 41 </ b> A (described later) of the head chip 26. The flow path member 31 for supplying is fixed.

  Above the flow path member 31, a pressure buffer 32 having a storage chamber for storing ink is disposed in a state supported by the base plate 30. The flow path member 31 and the pressure buffer 32 are connected via an ink connecting pipe 33, and the ink pipe 11 is connected to the pressure buffer 32.

  The ink supplied to the pressure buffer 32 via the ink pipe 11 is temporarily stored in the storage chamber of the pressure buffer 32, and then a predetermined amount of the ink is supplied to the common ink chamber 41 </ b> A via the ink connection pipe 33 and the flow path member 31. To be supplied. The flow path member 31, the pressure buffer 32, and the ink connection pipe 33 function as the ink supply unit 27.

  An IC substrate 36 on which a control circuit (drive circuit) 35 such as an integrated circuit for driving the head chip 26 is mounted is attached to the fixed plate 25. The control circuit 35 and the common electrode 50 and the individual electrode 52 (to be described later) of the head chip 26 are electrically connected via a flexible substrate 37 on which a wiring pattern (not shown) is printed.

  As a result, the control circuit 35 can apply a drive voltage between the common electrode 50 and the individual electrode 52 via the flexible substrate 37. Note that the IC substrate 36 and the flexible substrate 37 on which these control circuits 35 are mounted function as the control means 28.

(Head chip)
As shown in FIGS. 3 and 4, the head chip 26 of the inkjet head 4 includes an actuator plate 40 as an actuator, a cover plate 41, a support plate 42, and a nozzle plate 43 in which a plurality of nozzles 43A are formed. It has.

  The head chip 26 (inkjet head 4) is a so-called edge chute type that ejects ink from a nozzle 43A that faces an end in the longitudinal direction of a discharge channel 45A described later.

  As shown in FIGS. 4 and 5, the actuator plate 40 is a laminated plate (laminated substrate) obtained by laminating two plates, a first actuator plate 40A and a second actuator plate 40B.

  Both the first actuator plate 40A and the second actuator plate 40B are piezoelectric substrates that are polarized in the thickness direction, for example, PZT (lead zirconate titanate) ceramic substrates, with the polarization directions of the substrates opposite to each other. It is joined. The actuator plate 40 is long in a first direction (arrangement direction) L2 orthogonal to the thickness direction L1 and short in a second direction L3 orthogonal to the thickness direction L1 and the first direction L2, and is substantially rectangular in plan view. Is formed.

  Since the inkjet head 4 of this embodiment is an edge shoot type, the thickness direction L1 of the actuator plate 40 coincides with the scanning direction X in the printer 1, and the first direction L2 is the transport direction Y and the second direction L3. Coincides with the vertical direction Z. In the present embodiment, among the side wall surfaces of the actuator plate 40, the side wall surface that faces the nozzle plate 43 is referred to as a front end surface 39A, and the side wall surface that is located on the opposite side of the second direction L3 from the front end surface 39A. This is referred to as a rear end face 39B.

  A plurality of channels 45 arranged at predetermined intervals in the first direction L2 are formed on one main surface (surface on which the cover plate 41 overlaps) 39C of the actuator plate 40. The plurality of channels 45 extend in a straight line along the second direction L3 in a state opened to the one main surface 39C side, and one side in the longitudinal direction opens to the front end surface 39A side of the actuator plate 40.

  A drive wall 46 is formed between the plurality of channels 45 and has a substantially rectangular cross section and extends in the second direction L3. Each channel 45 is divided by the drive wall 46.

  The plurality of channels 45 are roughly divided into an ejection channel 45A filled with ink and a dummy channel 45B not filled with ink. The discharge channels 45A and the dummy channels 45B are alternately arranged in the first direction L2.

  Among these, the discharge channel 45 </ b> A is formed in a state of opening only to the front end surface 39 </ b> A side without opening to the rear end surface 39 </ b> B side of the actuator plate 40. On the other hand, the dummy channel 45B is formed to open not only on the front end surface 39A side of the actuator plate 40 but also on the rear end surface 39B side.

  A common electrode 50 is formed on the inner wall surface of the discharge channel 45A, that is, the pair of side wall surfaces and the bottom wall surface facing the first direction L2. The common electrode 50 extends in the second direction L3 along the discharge channel 45A and is electrically connected to a common terminal 51 formed on one main surface 39C of the actuator plate 40. Note that a common electrode 50 is formed on an inner wall surface of the ejection channel 45 </ b> A through an insulating film (not shown) at a portion overlapping a common ink chamber 41 </ b> A described later in plan view.

  On the other hand, of the inner wall surface of the dummy channel 45B, individual electrodes 52 are formed on the pair of side wall surfaces facing the first direction L2 so as to be electrically separated from each other. Each of the individual electrodes 52 extends in the second direction L3 along the dummy channel 45B and is electrically connected to an individual terminal 53 formed on one main surface 39C of the actuator plate 40.

  The individual terminals 53 are formed on the rear end surface 39B side on the one main surface 39C of the actuator plate 40. The individual electrodes 52 located on both sides of the ejection channel 45A (individual electrodes 52 formed in different dummy channels 45B) are connected to each other.

  At this time, the individual terminal 53 extends in the first direction L2 at a position separated from the common terminal 51 on the rear end surface 39B side on the one main surface 39C so as to connect the individual electrodes 52 in a bridge shape. Is formed.

  When the control circuit 35 applies a drive voltage between the common electrode 50 and the individual electrode 52 through the common terminal 51 and the individual terminal 53 via the flexible substrate 37, the drive wall 46 is deformed in a shear mode (shear mode). As a result, pressure waves are generated in the ink in the ejection channel 45A, and the ink in the ejection channel 45A is ejected from the nozzle 43A, so that various information such as characters and images can be recorded on the recording medium S.

  Here, a common electrode 50 is formed on the inner wall surface of the ejection channel 45A over the common ink chamber 41A in plan view with an insulating film interposed therebetween. For this reason, the ejection channel 45A is formed with a drive region that is deformed by the application of the drive voltage and substantially contributes to the ink ejection operation, and a non-drive region that hardly contributes to the ink ejection operation. The driving area is a pressure chamber 60 described later, and the non-driving area is an ink introduction path 62 as a liquid flow path described later.

  As shown in FIGS. 3 and 4, the cover plate 41 is superimposed on one main surface 39 </ b> C of the actuator plate 40. In the cover plate 41, a common ink chamber 41A to which ink is supplied via the flow path member 31 shown in FIG. 2 is formed in a rectangular shape in plan view that is long in the first direction L2.

  The common ink chamber 41A is provided with an ink regulating plate 55 in which a plurality of slits 55A are formed. The plurality of slits 55A are formed at positions corresponding to the ejection channel 45A, and the ink in the common ink chamber 41A is introduced only into the ejection channel 45A by the ink regulating plate 55, and the introduction into the dummy channel 45B is regulated. .

  The cover plate 41 is formed of, for example, the same PZT ceramic substrate as the actuator plate 40, and suppresses warping and deformation with respect to a temperature change by causing the same thermal expansion as the actuator plate 40. However, the present invention is not limited to this case, and the cover plate 41 may be formed of a material different from that of the actuator plate 40. However, it is preferable that the actuator plate 40 and the cover plate 41 are made of materials having close thermal expansion coefficients.

  The support plate 42 supports the actuator plate 40 and the cover plate 41 that are superimposed, and simultaneously supports the nozzle plate 43. A fitting hole 42A is formed in the support plate 42 along the first direction L2, and the overlapped actuator plate 40 and cover plate 41 are supported in a state of being fitted in the fitting hole 42A. . At this time, the support plate 42 is combined with the front end surface 39A of the actuator plate 40 so as to be flush with the front end surface 39A.

  The nozzle plate 43 is fixed to the front end face 39A of the support plate 42 and the actuator plate 40 by, for example, adhesion, and is a plate-like member formed of, for example, glass. Note that a surface of the nozzle plate 43 facing the recording medium S may be coated with a water repellent film for preventing ink adhesion or the like, for example.

  Further, the nozzle plate 43 is formed with a plurality of nozzles 43A arranged in a line at a predetermined interval in the first direction L2. The nozzles 43A are formed at positions facing the plurality of discharge channels 45A, and communicate with each discharge channel 45A. Further, as shown in FIG. 6, the nozzle 43A is formed in a tapered shape so as to be gradually tapered.

  Specifically, the hole diameter of the surface 44B on the actuator plate 40 side of the nozzle plate 43 of the nozzle 43A is set to about 60 μm, for example. On the other hand, the hole diameter of the surface 44A on the ink droplet ejection side of the nozzle plate 43 of the nozzle 43A is set to about 30 μm, for example. An appropriate meniscus is maintained in each nozzle 43A so that ink is not ejected from the nozzle 43A during normal operation.

  As shown in FIGS. 5 and 6, the ejection channel 45 </ b> A includes a pressure chamber 60 and an ink introduction path 62 as a liquid flow path. As described above, the pressure chamber 60 is a driving region that is deformed by the application of the driving voltage and substantially contributes to the ink ejecting operation. As shown in FIG. 6, the front end side of the ejection channel 45A (the nozzle plate 43). On the side facing the surface).

  The pressure chamber 60 has one end (front end side) in the longitudinal direction communicating with the nozzle 43 </ b> A, and the other end side (rear end side) in the longitudinal direction is an open end that serves as a connection portion with the ink introduction path 62. 60A.

  On the other hand, as described above, the ink introduction path 62 is a non-driving area that hardly contributes to the ink ejection operation, and is provided in a portion overlapping the common ink chamber 41A on the rear end side of the ejection channel 45A in plan view. . The ink introduction path 62 communicates with the common ink chamber 41 </ b> A through the slit 55 </ b> A of the cover plate 41 at the top, and is connected to the opening end 60 </ b> A of the pressure chamber 60 at the front end side.

  Further, a filter 64 composed of a plurality of cylindrical protrusions 64A is provided on the extension line in the longitudinal direction of the pressure chamber 60 in the ink introduction path 62. The protrusions 64 </ b> A protrude from the bottom wall surface of the ink introduction path 62 at intervals from each other, and the protrusion height of the protrusion 64 </ b> A is substantially the same as the height of the opening end 60 </ b> A of the pressure chamber 60.

  Further, the protrusion 64 </ b> A (filter 64) is provided at a position away from the opening end correction distance L with respect to the opening end 60 </ b> A of the pressure chamber 60. Here, the “opening end correction distance L” is a distance derived from the opening area of the opening end 60 </ b> A, and is a substantial reflection position of the pressure wave in the pressure chamber 60. For example, when the pressure chamber 60 is a circular pipe having a radius r, the opening end correction distance L can be obtained by 0.6r.

(Function and effect)
When recording information on the recording medium S by the printer 1 configured as described above, for example, the recording medium S is conveyed in the conveying direction Y by a pair of conveying means 2 and 3 as shown in FIG. However, each inkjet head 4 is reciprocated in the scanning direction X by the scanning means 6 via the carriage 16.

  During this time, in each inkjet head 4, a drive voltage is applied between the common terminal 51 and the individual terminal 53 by the control circuit 35, thereby causing the drive wall 46 to deform in a shear mode (shear mode). At this time, since the individual electrodes 52 formed on the pair of opposing side wall surfaces of the dummy channel 45B are electrically separated from each other, each drive wall 46 can be driven individually.

  Here, first, the drive wall 46 is deformed so as to increase the volume of the ejection channel 45A, whereby the ink in the common ink chamber 41A is supplied into the ink introduction path 62 through the slit 55A, and the ink introduction path 62 is supplied. The ink inside flows into the pressure chamber 60 from the opening end 60A (connection portion).

  Next, the drive wall 46 is deformed so as to reduce the volume of the ejection channel 45 </ b> A, so that a pressure wave is generated in the ink filled in the pressure chamber 60. Due to this pressure wave, the internal pressure of the pressure chamber 60 increases, so that ink can be ejected from the nozzle 43A, and various information such as characters and images can be recorded on the recording medium S by the ink droplets ejected from the nozzle 43A. it can.

  Note that the pressure wave generated in the pressure chamber 60 travels along the longitudinal direction of the pressure chamber 60 to the nozzle 43A side which is one side and the ink introduction path 62 side which is the other side. The pressure wave that has traveled toward the ink introduction path 62 is reflected at a position away from the opening end 60A, which is a connection portion with the ink introduction path 62, at an opening end correction distance L, and most of the pressure wave returns into the pressure chamber 60. The pressure wave leaks into the ink introduction path 62 without being reflected.

  Here, according to the present embodiment, since the filter 64 is provided in the ink introduction path 62, the pressure wave leaking from the pressure chamber 60 into the ink introduction path 62 is absorbed by the filter 64 and reduced. Can do. For this reason, so-called crosstalk that disturbs the ejection behavior of the ink ejected from the nozzles 43 </ b> A of the other pressure chambers 60 via the ink introduction path 62 can be suppressed.

  In addition, according to the present embodiment, since the filter 64 is provided on the extension line in the longitudinal direction of the pressure chamber 60, ink is introduced from the pressure chamber 60 as compared with a configuration not provided on the extension line in the longitudinal direction. The pressure wave leaking into the passage 62 can be efficiently absorbed by the filter 64.

  Further, the filter 64 is provided at a position away from the opening end correction distance L with respect to the opening end 60 </ b> A of the pressure chamber 60. Therefore, the opening area of the opening end 60A of the pressure chamber 60 can be suppressed from being narrowed by the filter 64, and the reflection of the pressure wave at the position away from the opening end 60A by the opening end correction distance L is reflected by the filter 64. It can be prevented that the reflectance of the pressure wave is reduced.

  Further, according to the present embodiment, since the filter 64 is composed of a plurality of protrusions 64A spaced apart from each other, it is compared with a configuration in which a damper made of an elastic body is provided in the ink introduction path 62 to absorb pressure waves. Thus, it is possible to prevent the inflow of ink into the pressure chamber 60 from being hindered.

  That is, since the protrusion 64A constituting the filter 64 hardly obstructs the ink flow, it is as close to the pressure chamber 60 as possible at a position away from the opening end correction distance L with respect to the opening end 60A of the pressure chamber 60. Can be arranged. Specifically, the distance between the filter 64 and the opening end 60A of the pressure chamber 60 can be less than 70 μm, preferably less than 50 μm, more preferably less than 30 μm.

  Further, according to the present embodiment, the filter 64 is formed by the plurality of protrusions 64A, so that the filter 64 can be easily manufactured and installed as compared with the configuration in which the filter is formed by the plurality of holes provided in the wall body or the like. can do.

Second Embodiment
Hereinafter, an ink jet head as a liquid jet head according to a second embodiment of the present invention will be described with reference to FIGS. Since the printer as the liquid jet recording apparatus has the same configuration as the printer 1 of the first embodiment, illustration and description thereof are omitted.

(Inkjet head)
The inkjet head 4 according to the first embodiment is configured to deform the pressure chamber 60 in the shear mode (shear mode) by the electrodes formed on both side walls of the pressure chamber 60, whereas the inkjet head according to the second embodiment. The head 66 is configured to be deformed in a bending mode (bent mode).

  Specifically, as shown in FIGS. 7 and 8, the head chip 68 of the inkjet head 66 includes a nozzle plate 70, a flow path forming plate 72 stacked on the nozzle plate 70, and a flow path forming plate 72. And a diaphragm 74 stacked on top of each other.

  In the flow path forming plate 72, an ink introduction path 76 as a liquid flow path and a pair of ink discharge paths 78A and 78B provided at positions sandwiching the ink introduction path 76 are arranged in parallel at a predetermined interval. Is formed. The ink introduction path 76 communicates with a supply common ink chamber (not shown), and the ink discharge paths 78A and 78B communicate with a discharge common ink chamber (not shown).

  Further, a plurality of pressures extending between the ink introduction path 76 and the ink discharge path 78A in the flow path forming plate 72 in a direction intersecting with the ink introduction path 76 and the ink discharge path 78A and arranged at intervals. A chamber 80 is formed. Both ends of the pressure chamber 80 in the longitudinal direction are open ends 80A and 80B, and the open ends 80A and 80B are connected to the ink introduction path 76 and the ink discharge path 78A.

  Similarly, between the ink introduction path 76 and the ink discharge path 78B in the flow path forming plate 72, a plurality of lines extending in a direction intersecting with the ink introduction path 76 and the ink discharge path 78B and arranged at intervals from each other. A pressure chamber 82 is formed.

  As with the pressure chamber 80, the pressure chamber 82 has both ends in the longitudinal direction as open ends 82A, and the open ends 82A serve as connecting portions between the ink introduction path 76 and the ink discharge path 78B. The pressure chambers 82 are alternately arranged with the pressure chambers 80 so that the central axis along the longitudinal direction is shifted from the central axis along the longitudinal direction of the pressure chamber 80.

  A diaphragm 74 is placed on top of the pressure chambers 80 and 82, and the diaphragm 74 is a top surface of the pressure chambers 80 and 82. An actuator plate (PZT ceramic substrate) 84 as an actuator is provided along the longitudinal direction of the pressure chambers 80 and 82 at positions corresponding to the plurality of pressure chambers 80 and 82 in the upper part of the diaphragm 74. A drive electrode (not shown) for applying a voltage to the actuator plate 84 to selectively deform the actuator plate 84 is formed on the diaphragm 74.

  As shown in FIG. 8, the nozzle plate 70 is formed with a nozzle 70 </ b> A that communicates with the central portion in the longitudinal direction of the bottom wall surface of the pressure chamber 80. The nozzle 70 </ b> A is formed at a position corresponding to the bottom wall surface of the plurality of pressure chambers 80 and 82 in the nozzle plate 70.

  Further, as shown in FIG. 7, a plurality of columnar projections 86A constituting the filter 86 are respectively provided at positions corresponding to the ink introduction path 76 and the ink discharge paths 78A and 78B on the upper surface of the nozzle plate 70. ing.

  The plurality of protrusions 86A are juxtaposed in two rows along the open ends 80A, 80B, and 82A, which are connection portions between the ink introduction paths 76 and the ink discharge paths 78A and 78B of the plurality of pressure chambers 80 and 82. The first row of protrusions 86A and the second row of protrusions 86A are arranged alternately.

  Further, as shown in FIG. 8, the protrusion 86 </ b> A (filter 86) is provided on the extension line in the longitudinal direction of the pressure chambers 80 and 82, and is open to the opening ends 80 </ b> A and 82 </ b> A of the pressure chambers 80 and 82. It is provided at a position separated from the end correction distance L. Furthermore, the protrusion height of the protrusion 86A is higher than the height of the opening ends 80A and 82A.

  In the present embodiment, the flow path forming plate 72 is made of, for example, a silicon wafer, and the ink introduction path 76, the ink discharge paths 78A and 78B, the pressure chambers 80 and 82, and the protrusion 86A (filter 86) are provided. It is formed by etching.

(Function and effect)
As with the inkjet head 4 of the first embodiment, the inkjet head 66 of the present embodiment performs an ink ejection operation by applying a drive voltage to a drive electrode (not shown) to deform the actuator plate 84.

  In the present embodiment, since the actuator plate 84 is provided above the pressure chambers 80 and 82, the diaphragm 74 is deformed in the bending mode (vent mode) when the actuator plate 84 is deformed.

  At this time, first, the diaphragm 74 is deformed to enlarge the volume of the pressure chambers 80 and 82, whereby the ink in the ink introduction path 76 flows into the pressure chambers 80 and 82 from the opening ends 80A and 82A (connection portion). Let

  Next, the diaphragm 74 is deformed to reduce the volume of the pressure chambers 80 and 82, thereby generating a pressure wave in the ink filled in the pressure chambers 80 and 82 and ejecting the ink from the nozzle 70A. The ink in the pressure chambers 80 and 82 that has not been ejected from the nozzle 70A is discharged to the ink discharge paths 78A and 78B.

  The pressure wave generated in the pressure chambers 80 and 82 travels along the longitudinal direction of the pressure chambers 80 and 82 toward the ink introduction path 76 and the ink discharge paths 78A and 78B. The pressure wave that has traveled toward the ink introduction path 76 and the ink discharge paths 78A and 78B is corrected to the opening end correction distance L from the opening ends 80A, 80B, and 82A, which are the connection portions between the ink introduction path 76 and the ink discharge paths 78A and 78B. Most of the light waves are reflected back to the pressure chambers 80 and 82, but some pressure waves are not reflected and leak into the ink introduction path 76 and the ink discharge paths 78A and 78B.

  Here, according to the present embodiment, the longitudinal direction of the pressure chambers 80 and 82 of the ink introduction path 76 and the ink discharge paths 78A and 78B and the opening ends 80A, 80B and 82A of the pressure chambers 80 and 82 are defined. Thus, a filter 64 is provided at a position farther from the opening end correction distance L.

  For this reason, as in the first embodiment, the pressure chamber is reduced by the filter 64 without reducing the reflectance of the pressure wave at the connection portion between the ink introduction path 76 and the ink discharge paths 78A and 78B and the pressure chambers 80 and 82. Pressure waves leaking from 80 and 82 into the ink introduction path 76 and the ink discharge paths 78A and 78B can be reduced.

  Further, the height of the protrusion 64A of the filter 64 is higher than the height of the opening ends 80A and 82A of the pressure chambers 80 and 82. For this reason, the height of the protrusion 64A is lower than the height of the opening ends 80A and 82A of the pressure chambers 80 and 82 from the pressure chambers 80 and 82 into the ink introduction path 76 and the ink discharge path 78A. The pressure wave leaking into 78B can be further reduced.

<Modification>
A modification of the head chip 68 of the inkjet head 66 according to the second embodiment of the present invention will be described below with reference to FIG. In addition, about the structure similar to 2nd Embodiment, while attaching | subjecting the same code | symbol, some illustrations and description are abbreviate | omitted.

  As described above, the pressure chamber 80 and the pressure chamber 82 face each other with the ink introduction path 76 interposed therebetween, and the central axis along the longitudinal direction of the pressure chamber 80 is the central axis along the longitudinal direction of the pressure chamber 82. On the other hand, they are alternately arranged so as to be displaced along the ink introduction path 76. That is, as shown in FIG. 9, the wall portion 88 constituting the side wall surfaces of the plurality of pressure chambers 80 and the wall portion 90 constituting the side wall surfaces of the plurality of pressure chambers 82 are provided at positions shifted from each other by a half pitch. Yes.

  Here, in this modification, a plurality of protrusions 92A of the filter 92 provided in the ink introduction path 76 are arranged between the wall parts 88 and 90 facing each other with a half-pitch deviation across the ink introduction path 76. , 90 are arranged side by side along an imaginary line M connecting the two.

  As a result, the filter 92 is provided in a zigzag shape in plan view so as to divide the pressure chambers 80, 82 facing each other and between the adjacent pressure chambers 80, between the pressure chambers 82. The plurality of protrusions 92 </ b> A are arranged in two rows and are provided at positions away from the opening end correction distance L with respect to the opening ends 80 </ b> A and 82 </ b> A of the pressure chambers 80 and 82.

(Function and effect)
According to this modification, the protrusion 82 </ b> A of the filter 92 is provided along the imaginary line M that connects the wall portions 88, 90 of the pressure chambers 80, 82 that face each other across the ink introduction path 76. Therefore, the filter 92 prevents the pressure wave leaking from the pressure chambers 80 and 82 into the ink introduction path 76 from disturbing the behavior of the ink in the other pressure chambers 80 and 82 in parallel and the other pressure chambers 80 and 82 facing each other. Can be further suppressed.

<Other embodiments>
As described above, the first and second embodiments and the modified examples of the present invention have been described. However, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It is.

  For example, in the first and second embodiments, the protrusions 64A, 86A, and 92A of the filters 64, 86, and 92 are circular cylinders in plan view. However, the shape of the protrusions 64A, 86A, and 92A is not limited to a circular shape, and may be a concave shape in a plan view, and is triangular in a plan view like the protrusion 94A of the filter 94 shown in FIG. It may be said.

  In the first and second embodiments, the protrusions 64A, 86A, and 92A of the filters 64, 86, and 92 protrude from the bottom wall surface of the ink introduction paths 62 and 76 or the ink discharge paths 78A and 78B. However, as shown in FIG. 10B, the protrusion 96A of the filter 96 is formed so as to protrude from the wall surface (flow path forming plate 72) facing the opening end 80B of the pressure chamber 80 toward the opening end 80B. Also good.

  By changing the shape and formation position of the protrusions 64A, 86A, 92A, 94A, and 96A, the reflection direction and the absorption rate of the pressure wave by the protrusions 64A, 86A, 92A, 94A, and 96A can be adjusted.

  In the above embodiment, the ink jet printer (printer 1) is described as an example of the liquid jet recording apparatus. However, the liquid jet recording apparatus is not limited to the ink jet printer, and may be a fax machine, an on-demand printing machine, or the like. There may be.

  Moreover, in the said embodiment, as an example of the inkjet heads 4 and 66, the non-circulation type edge chute type which deform | transforms the pressure chamber 60 by shear mode (shear mode), and the pressure chambers 80 and 82 by bending mode (vent mode). The circulation side shoot type to be deformed was explained. However, the inkjet head may be a circulation side shoot type that is deformed in a shear mode (shear mode) or a non-circulation type side shoot type that is deformed in a bending mode (vent mode).

  Furthermore, in the above-described embodiment, the filters 64, 86, and 92 are provided so as to be separated from the opening ends 60A, 80A, 80B, and 82A of the pressure chambers 60, 80, and 82 by the opening end correction distance L. explained. However, the filters 64, 86, and 92 are provided at least at a position where pressure waves leaking from the open ends 60A, 80A, 80B, and 82A can be reduced, and at positions away from the open ends 60A, 80A, 80B, and 82A. It only has to be done.

  By separating the filters 64, 86, and 92 from the opening ends 60A, 80A, 80B, and 82A, the pressure chamber 60 is compared with the configuration in which the filters 64, 86, and 92 are in contact with the opening ends 60A, 80A, 80B, and 82A. , 80 and 82 can be prevented from reducing the reflectance of the pressure wave at the open ends 60A, 80A, 80B and 82A.

  In the above embodiment, the filters 64, 86, 92, 94, and 96 are configured by the plurality of protrusions 64 </ b> A, 86 </ b> A, 92 </ b> A, 94 </ b> A, and 96 </ b> A, but a plurality of holes are formed in the wall body and film body. The filter may be configured with

1 Printer (an example of a liquid jet recording device)
4, 66, 100 Inkjet head 5 Ink supply means (an example of liquid supply means)
6 Scanning means 40, 74, 118 Actuator plate (an example of an actuator)
43, 70, 104 Nozzle plate 43A, 70A, 104A Nozzle 60, 80, 82 Pressure chamber 60A, 80A, 80B, 82A Open end (an example of a connecting portion)
62, 76 Ink introduction path (an example of a liquid flow path)
64, 86, 92, 94, 96 Filter 64A, 86A, 92A, 94A, 96A Projection 88, 90 Wall L Open end correction distance M Virtual line

Claims (6)

A liquid flow path through which liquid is supplied;
A plurality of pressure chambers connected to the liquid flow path and into which liquid flows;
A nozzle plate arranged facing the pressure chamber and having nozzles formed thereon;
An actuator for varying the volume of the pressure chamber and ejecting the liquid in the pressure chamber as droplets from the nozzle;
A filter that is provided on the liquid flow path side away from a connection portion between the liquid flow path and the pressure chamber, and through which the liquid passes;
A liquid ejecting head.   The filter is provided on an extension line in the longitudinal direction of the pressure chamber, and is provided farther from the connection portion toward the liquid flow path than an opening end correction distance derived from an opening area of the connection portion of the pressure chamber. The liquid ejecting head according to claim 1.   The liquid ejecting head according to claim 1, wherein a height of the filter is higher than a height of a connection portion of the pressure chamber.   The liquid ejecting head according to claim 1, wherein the filter is configured by a plurality of protrusions protruding from an inner wall surface of the liquid flow path at intervals. The pressure chamber is provided in parallel on both sides across the liquid flow path, and a connection portion between the liquid flow path and the pressure chamber is displaced in a direction along the liquid flow path,
The liquid ejecting head according to claim 4, wherein the protrusions are arranged along an imaginary line that connects the walls configuring the pressure chambers facing each other across the liquid flow path. The liquid jet head according to any one of claims 1 to 5,
Liquid supply means for supplying liquid to the liquid ejecting head;
Scanning means for scanning the liquid ejecting head in a direction intersecting the conveyance direction of the recording medium;
A liquid jet recording apparatus having:

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