JP5569047B2 - Liquid ejecting head and liquid ejecting apparatus - Google Patents

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus that supply liquid from a manifold to a plurality of pressure chambers via a liquid supply path.

As a typical example of the liquid ejecting head, for example, an ink jet recording head that ejects ink from a plurality of nozzle openings constituting a nozzle row by using a pressure change in a pressure chamber due to displacement of a piezoelectric element that is a pressure generating unit. Are known.
Specifically, a piezoelectric element is provided in a pressure chamber communicating with the nozzle opening, and a voltage is applied to the piezoelectric element to contract or expand the piezoelectric element so that the pressure chamber is depressurized to supply ink or the pressure chamber. Pressure is applied and ink is ejected from the nozzle openings.
The ink is stored in ink supply means such as an ink cartridge, passes through the ink introduction path, is supplied from the ink introduction port to the manifold, and is supplied to the plurality of pressure chambers through the ink supply path.
There is known a structure in which an ink introduction port is provided in a reservoir which is a manifold, and ink is supplied from the ink introduction port to a pressure chamber via an ink supply path and a communication path (see, for example, Patent Document 1).
In addition, a structure is known in which ink is branched into a manifold and an air chamber by an ink supply chamber, and air is confined in the air chamber (see, for example, Patent Document 2).

Japanese Patent Laying-Open No. 2009-96128 (page 7, FIG. 2) JP 2008-126646 A (page 9, FIG. 5)

The bubbles that have entered the manifold from the liquid introduction port are likely to enter the pressure chamber through the liquid supply path and the communication path because the liquid flow is directed toward the liquid supply path and the communication path. Bubbles that have entered the pressure chamber absorb pressure in response to pressure changes in the pressure chamber. As a result, the pressure chamber is not sufficiently pressurized and a liquid ejection failure occurs.
In addition, even when branched into the manifold and the air chamber, bubbles that directly enter the manifold exist with a certain probability, and liquid ejection failure occurs.

  The present invention has been made to solve the above-described problems, and can be realized as the following forms or application examples.

[Application Example 1]
A pressure chamber communicating with a nozzle opening for injecting liquid, pressure generating means for changing the pressure in the pressure chamber, a manifold that is a common liquid chamber communicating with the plurality of pressure chambers, a plurality of the pressure chambers, and A liquid supply path that communicates with the manifold, a liquid introduction path that supplies the liquid to the manifold, a bubble storage portion that is formed in the manifold and is located in a direction opposite to the gravitational direction from the liquid introduction path, and the manifold And an outlet of the liquid introduction path that allows the liquid to flow out from the liquid supply path to the manifold, and the outlet of the liquid introduction path is in the direction of gravity relative to the liquid supply path in the manifold. together are arranged in the opposite direction, liquid is gravity direction the liquid to said manifold, characterized in that to flow out in the opposite direction Injection head.
In the liquid ejecting head, the manifold has a bottom surface disposed in a direction opposite to the direction of gravity from the liquid supply path, and the outlet of the liquid introduction path is provided on the bottom surface. And

According to this application example, the liquid flowing through the liquid introduction path flows out from the outlet of the liquid introduction path in a direction opposite to the direction of gravity, so that bubbles generated or entered before the liquid introduction path exits into the liquid flow. It rides toward the bubble reservoir formed in the direction opposite to the direction of gravity. In addition, buoyancy acting in the direction opposite to the direction of gravity also causes the bubbles to go in the direction opposite to the direction of gravity. The air bubbles that have reached the air bubble storage unit are combined with each other to form a larger air bubble or space and are less likely to be taken into the liquid. Therefore, intrusion of bubbles into the pressure chamber via the liquid supply path communicating from the manifold to the pressure chamber is suppressed, and when the pressure is increased by the pressure generating means to eject the liquid from the nozzle opening, A liquid ejecting head with reduced pressure loss due to bubbles and reduced liquid ejection defects can be obtained.
Here, the range opposite to the gravitational direction includes not only a direction having an angle of 180 ° with respect to the gravitational direction but also a direction having an angle greater than 90 ° and smaller than 180 °.

[Application Example 2]
In the liquid ejecting head, the outlet is formed in a direction opposite to a gravitational direction from the liquid supply path.
In this application example, since the outlet of the liquid introduction path is formed in the direction opposite to the gravity direction from the liquid supply path, bubbles that travel in the direction opposite to the gravity direction together with the liquid are formed in the liquid supply path formed in the gravity direction. Thus, a liquid ejecting head that is less likely to enter and that has reduced liquid ejection defects can be obtained.

[Application Example 3]
In the liquid ejecting head, the manifold includes a first common liquid chamber and a second common liquid chamber, and the first common liquid chamber communicates with the pressure chamber via the liquid supply path. The liquid ejecting head, wherein the two common liquid chambers are formed with the bubble storage portion and the outlet, and include a communication path that communicates the first common liquid chamber and the second common liquid chamber.
In this application example, the manifold is formed separately from the first common liquid chamber and the second common liquid chamber through the communication path, and the second common liquid chamber includes a bubble storage section. The liquid flows out from the outlet of the liquid introduction path in the direction opposite to the direction of gravity, and the bubbles in the liquid are stored in the bubble storage part of the second common liquid chamber. Compared to the case where the manifold has one chamber, the bubbles stored in the second common liquid chamber are less likely to enter the first common liquid chamber through the communication path. Accordingly, intrusion of bubbles from the first common liquid chamber to the pressure chamber is further suppressed, and a liquid ejecting head with reduced liquid ejection defects can be obtained.

[Application Example 4]
In the liquid ejecting head, the outlet is formed in a direction opposite to a gravitational direction from the communication path.
In this application example, since the outlet of the liquid introduction path is formed in the direction opposite to the gravity direction from the communication path, bubbles that move in the direction opposite to the gravity direction together with the liquid are caused by the communication path formed in the gravity direction. A liquid ejecting head that is difficult to enter and has a reduced liquid ejection defect is obtained.

[Application Example 5]
The liquid ejecting head according to claim 1, wherein a region on the opposite side to the gravitational direction of the bubble reservoir has a convex shape in a direction opposite to the gravitational direction.
In this application example, the bubbles that have flowed in the direction opposite to the gravity direction along with the outflow of the liquid from the outlet of the liquid introduction path reach the region on the opposite side to the gravity direction of the bubble storage portion. The bubbles gather at the top of the convex shape, move away from the liquid supply path or the communication path, and are difficult to move from the top of the convex shape. Accordingly, it is possible to obtain a liquid ejecting head in which bubbles are further prevented from entering the liquid supply path or the communication path and liquid ejection defects are further reduced.

[Application Example 6]
A liquid ejecting apparatus comprising the liquid ejecting head.

  According to this application example, a liquid ejecting apparatus having the above-described effects can be obtained.

1 is a schematic perspective view illustrating an ink jet recording apparatus according to a first embodiment. FIG. 2 is an exploded perspective view illustrating a schematic configuration of an ink jet recording head. (A) is a partial top view of an inkjet recording head, (b) is an AA schematic sectional drawing in (a). FIG. 9 is an exploded perspective view illustrating a schematic configuration of an ink jet recording head according to a second embodiment. (A) is a partial top view of an inkjet recording head, (b) is a BB schematic sectional drawing in (a). FIG. 9 is an exploded perspective view showing a schematic configuration of an ink jet recording head in Modification 1; (A) is a partial top view of an inkjet recording head, (b) is CC schematic sectional drawing in (a). FIG. 4 is a schematic cross-sectional view corresponding to the AA schematic cross-sectional view of FIG. FIG. 10 is a schematic cross-sectional view of an ink jet recording head according to a third embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic perspective view illustrating an ink jet recording apparatus 1000 as an example of a liquid ejecting apparatus according to the present embodiment. The ink jet recording apparatus 1000 is an apparatus that performs recording by ejecting ink as a liquid onto a recording sheet S that is a recording medium. In FIG. 1, the gravity direction g is shown.

In FIG. 1, an ink jet recording apparatus 1000 includes recording head units 1A and 1B each having an ink jet recording head 1 as a liquid ejecting head. The recording head units 1A and 1B are detachably provided with cartridges 2A and 2B constituting ink supply means.
Here, the ink jet recording head 1 is provided on the side of the recording head units 1A and 1B facing the recording sheet S, and is not shown in FIG.

  The carriage 3 on which the recording head units 1A and 1B are mounted is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B discharge, for example, a black ink composition and a color ink composition, respectively, toward the recording sheet S in the gravity direction g.

Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted moves along the carriage shaft 5. .
On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage 3. The platen 8 can be rotated by a driving force of a paper feed motor (not shown), and a recording sheet S which is a recording medium such as paper fed by a paper feed roller is wound around the platen 8 and conveyed. It has become so.

Hereinafter, the ink jet recording head 1 will be described in detail with reference to FIGS. 2 and 3.
FIG. 2 is an exploded perspective view showing a schematic configuration of an ink jet recording head 1 as a liquid ejecting head according to the present embodiment, FIG. 3A is a partial plan view of the ink jet recording head 1, and FIG. ) Is an AA schematic cross-sectional view in (a).
2 and 3, the ink jet recording head 1 includes a flow path forming substrate 10, a nozzle plate 20, and a protective substrate 30. The ink jet recording head 1 is assembled by sandwiching a flow path forming substrate 10 between a nozzle plate 20 and a protective substrate 30.
The nozzle plate 20 faces the recording sheet S shown in FIG. 2 and 3 also show the gravity direction g.

The flow path forming substrate 10 is composed of a silicon single crystal substrate having a plane orientation (110) which is a silicon substrate, and an elastic film 50 having a thickness of 2 μm formed in advance by thermal oxidation is formed on one surface thereof.
A plurality of pressure chambers 12 partitioned by a partition wall 11 are arranged in parallel on the flow path forming substrate 10. Further, a communication portion 13 is formed in a region outside the pressure chamber 12 in the longitudinal direction of the flow path forming substrate 10, and the communication portion 13 and each pressure chamber 12 serve as a liquid supply path provided for each pressure chamber 12. The ink supply path 14 communicates.
The communication portion 13 constitutes a part of the manifold 200 that communicates with the protective substrate 30 and serves as a common ink chamber for the pressure chambers 12. The ink supply path 14 is formed with a narrower width than the pressure chamber 12, and keeps the flow path resistance of the ink L flowing into the pressure chamber 12 from the communicating portion 13 constant.

  Further, on the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end of each pressure chamber 12 on the side opposite to the ink supply path 14 is provided with a mask film 52. It is fixed by an adhesive, a heat welding film or the like via The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, or stainless steel.

On the other hand, an actuator 100 as pressure generating means is provided on the side opposite to the opening surface of the flow path forming substrate 10. The actuator 100 includes a diaphragm 53 and a piezoelectric element 300 that is a driving means.
The diaphragm 53 includes an elastic film 50 having a thickness of about 1.00 μm, for example, and an insulator film 54 made of zirconium oxide formed on the elastic film 50 and having a thickness of about 0.35 μm. .
The piezoelectric element 300 is formed in a region facing the pressure chamber 12 through the vibration plate 53.

On the insulator film 54, a lower electrode 60 having a thickness of, for example, about 0.10 to 0.20 μm, a piezoelectric layer 70 having a thickness of, for example, about 0.50 to 5.00 μm, and a thickness of For example, the piezoelectric element 300 including the upper electrode 80 of about 0.05 μm is formed.
In general, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure chamber 12. In the embodiment, the lower electrode 60 is a common electrode of the piezoelectric element 300, and the upper electrode 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring.

  In addition, a lead electrode 90 made of, for example, gold (Au) or the like is connected to the upper electrode 80 of each piezoelectric element 300, and a voltage is selectively applied to each piezoelectric element 300 via the lead electrode 90. It is to be applied.

A protective substrate 30 having a piezoelectric element holding portion 31 for protecting the piezoelectric element 300 is bonded to the flow path forming substrate 10 in an area facing the piezoelectric element 300 by an adhesive or the like.
The piezoelectric element holding part 31 only needs to secure a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or not sealed.

In the protective substrate 30, a reservoir portion 32 including a bubble storage portion 322 is formed in a region facing the communication portion 13, and this reservoir portion 32 is communicated with the communication portion 13 of the flow path forming substrate 10 to be connected to each other. A manifold 200 serving as an ink chamber common to the pressure chambers 12 is configured. The bubble storage part 322 is located near the surface 321 in the direction opposite to the gravity direction g of the reservoir part 32.
In addition, an ink introduction path 33 for introducing the ink L into the reservoir portion 32 is formed in the protective substrate 30. The ink introduction path 33 has a J-shaped tube shape.
The inlet 331 of the ink introduction path 33 is formed on the upper surface 301 of the protective substrate 30. On the other hand, the outlet 332 of the ink introduction path 33 is formed in the reservoir portion 32 so as to open in the direction opposite to the gravity direction g.
The outlet 332 is preferably formed in the direction opposite to the gravitational direction g from the ink supply path 14. Here, a plurality of ink introduction paths 33 may be formed.

Ink L is supplied to the inlet 331 of the ink introduction path 33 from the cartridge 2A or 2B shown in FIG. 1 in the gravitational direction g as indicated by an arrow in the drawing.
The supplied ink L passes through the J-shaped ink introduction path 33 and flows out in the direction opposite to the gravity direction g as indicated by an arrow in the drawing at the outlet 332. In the following embodiments and modifications, the flow of the ink L is indicated by arrows in the drawing.
In the figure, it flows out in a direction having an angle of 180 ° with respect to the gravitational direction g, but the range opposite to the gravitational direction g is 90 ° in addition to the direction having an angle of 180 ° with respect to the gravitational direction g. Includes directions having an angle greater than 180 °.

A through hole 34 that penetrates the protective substrate 30 in the thickness direction is provided in a region between the piezoelectric element holding portion 31 and the manifold 200 of the protective substrate 30, and a part of the lower electrode 60 and the through hole 34 are provided in the through hole 34. The leading end of the lead electrode 90 is exposed, and one end of a connection wiring extending from a drive IC (not shown) is connected to the lower electrode 60 and the lead electrode 90.
As the protective substrate 30, it is preferable to use a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, a ceramic material, a silicon single crystal substrate, or the like.

  In the ink jet recording head 1, the ink L is taken from the cartridge 2 </ b> A or 2 </ b> B shown in FIG. 1, and the interior from the manifold 200 to the nozzle opening 21 is filled with the ink L. A voltage is applied between the lower electrode 60 and the upper electrode 80 corresponding to 12. By applying the voltage, the elastic film 50 and the piezoelectric layer 70 are bent and deformed, the pressure in each pressure chamber 12 is increased, and the ink L is ejected from the nozzle openings 21.

FIG. 3B also shows a state where the bubbles B are taken in when the ink L is supplied from the cartridge 2A or 2B shown in FIG.
According to the present embodiment described above, the following effects can be obtained.
(1) Since the ink L flowing through the ink introduction path 33 flows out from the outlet 332 of the ink introduction path 33 in the direction opposite to the gravity direction g, the bubble B generated or entered until the outlet 332 of the ink introduction path 33 is It rides on the flow of the ink L and moves toward the bubble reservoir 322 formed in the direction opposite to the gravity direction g. In addition, the bubble B is directed in the direction opposite to the gravity direction g due to the buoyancy acting in the direction opposite to the gravity direction g. The bubbles B that have reached the bubble storage unit 322 are combined with each other to form a larger bubble B or space and are less likely to be taken into the ink L. Accordingly, it is possible to suppress the intrusion of the bubbles B into the pressure chamber 12 through the ink supply path 14 communicating from the manifold 200 to the pressure chamber 12, and the pressure in the pressure chamber 12 is increased by the actuator 100 and the ink L from the nozzle opening 21. When the ink is discharged, the pressure loss due to the bubbles B in the pressure chamber 12 can be reduced, and the ink jet recording head 1 in which the discharge failure of the ink L is reduced can be obtained.

  (2) Since the outlet 332 of the ink introduction path 33 is formed in the direction opposite to the gravitational direction g from the ink supply path 14, the bubbles B that move in the direction opposite to the gravitational direction g together with the ink L are moved in the gravitational direction g. It is possible to obtain the ink jet recording head 1 which can be made difficult to enter by the formed ink supply path 14 and in which the ejection failure of the ink L is further reduced.

(3) When the pressure in the pressure chamber 12 is increased, not only the ink L is ejected from the nozzle opening 21 but also the ink L from the ink supply path 14 that connects the pressure chamber 12 and the manifold 200 to the manifold 200 side. A jet is generated. As a result, the pressure in the manifold 200 fluctuates, and the fluctuation in pressure propagates to the pressure chamber 12 communicating with the adjacent nozzle opening 21 to change the discharge characteristics, so that so-called crosstalk occurs.
By the bubbles B being accumulated in the bubble reservoir 322 of the manifold 200, the pressure fluctuation in the manifold 200 due to the ink jet flow is absorbed by the bubbles B accumulated in the bubble reservoir 322, and the change in ejection characteristics due to the pressure fluctuation is alleviated. Can do. Therefore, it is possible to prevent crosstalk between adjacent pressure chambers 12 and to prevent occurrence of print density.

  (4) The ink jet recording apparatus 1000 having the above-described effects can be obtained.

(Second Embodiment)
FIG. 4 is an exploded perspective view showing a schematic configuration of the ink jet recording head 101 in the present embodiment, FIG. 5A is a partial plan view of the ink jet recording head 101, and FIG. It is BB schematic sectional drawing. The same components as those in the first embodiment are denoted by the same reference numerals.
This embodiment is different from the first embodiment in that the manifold structure and a plurality of ink introduction paths are formed. The manifold 400 of the present embodiment includes a first common liquid chamber 410 and a second common liquid chamber 420 in which a bubble reservoir 322 is formed.

The first common liquid chamber 410 corresponds to the communication portion 13 in the first embodiment, and is formed on the flow path forming substrate 10. The second common liquid chamber 420 is formed across the flow path forming substrate 10 and the protective substrate 30. A slit-shaped communication path 430 is formed between the first common liquid chamber 410 and the second common liquid chamber 420 in the direction in which the pressure chambers 12 are arranged in parallel. The two common liquid chambers 420 communicate with each other through a communication passage 430.
Here, the common liquid chamber is not limited to the two chambers of the first common liquid chamber 410 and the second common liquid chamber 420, but one or more common liquid chambers are provided between the first common liquid chamber 410 and the second common liquid chamber 420. A liquid chamber may be provided. For example, in addition to the first common liquid chamber 410 and the second common liquid chamber 420, a common liquid chamber connected to the communication passage 430 may be provided.

In the second common liquid chamber 420, the ink introduction path 33 is formed as in the first embodiment. The shape of the ink introduction path 33 is the same as that of the first embodiment. The outlet 332 of the ink introduction path 33 is preferably formed in the direction opposite to the gravity direction g from the communication path 430.
In the present embodiment, a plurality of ink introduction paths 33 are formed.

According to the present embodiment described above, the following effects can be obtained.
(5) The manifold 400 is formed separately from the first common liquid chamber 410 and the second common liquid chamber 420 through the communication path 430, and the second common liquid chamber 420 includes the bubble storage part 322. The ink L flows out from the outlet 332 of the ink introduction path 33 in the direction opposite to the gravity direction g, and the bubbles B in the ink L are stored in the bubble storage part 322 of the second common liquid chamber 420. Compared with the case where the manifold has one chamber, the bubbles B stored in the second common liquid chamber 420 are less likely to enter the first common liquid chamber 410 by the communication path 430. Accordingly, the bubble B can be prevented from entering the pressure chamber 12 from the first common liquid chamber 410, and the ink jet recording head 101 can be obtained in which the ejection failure of the ink L is further reduced.

  (6) Since the outlet 332 of the ink introduction path 33 is formed in the direction opposite to the gravitational direction g from the communication path 430, the bubbles B that go in the direction opposite to the gravitational direction g together with the ink L are in the gravitational direction g. It is possible to obtain the ink jet recording head 101 which is less likely to enter due to the formed communication path 430 and in which defective ejection of the ink L is further reduced.

  (7) Since a plurality of ink introduction paths 33 are formed, ink L can be easily supplied from the cartridge 2A or 2B shown in FIG. 1 to the manifold 400 without resistance.

(Modification 1)
FIG. 6 is an exploded perspective view showing a schematic configuration of the ink jet recording head 102 in this modification, FIG. 7A is a partial plan view of the ink jet recording head 102, and FIG. 7B is a diagram of FIG. It is CC schematic sectional drawing. The same components as those in the first embodiment are denoted by the same reference numerals.
This modification differs from the first embodiment in the shape of the ink introduction path. The ink introduction path 35 of this modification has a J-shaped cross section in the direction in which the pressure chambers 12 are arranged in parallel, and is formed in a slit shape in the direction in which the pressure chambers 12 are arranged in parallel. . Therefore, the inlet 351 and the outlet 352 have an elongated rectangular shape.

According to the modification described above, the following effects can be obtained.
(8) Since the ink introduction path 35 is formed in a slit shape, the opening area of the inlet 351 and the outlet 352 can be increased, and the supply of the ink L from the cartridge 2A or 2B shown in FIG. It can be done more easily.

(Modification 2)
FIG. 8 is a schematic cross-sectional view showing a schematic configuration of the ink jet recording head 103 in this modification. The schematic cross-sectional view of this modification corresponds to the AA schematic cross-sectional view of FIG. The same components as those in the first embodiment are denoted by the same reference numerals.
This modification differs from the first embodiment in the shape of the reservoir. The reservoir portion 36 of this modification has a surface 323 on the side opposite to the direction of gravity g inclined. Specifically, the surface 323 opposite to the gravity direction g of the bubble storage portion 324 is inclined so as to move away from the outlet 332 in the direction opposite to the gravity direction g. Therefore, the region on the opposite side to the gravity direction g of the bubble reservoir 324 has a convex shape in the direction opposite to the gravity direction g.

According to the modification described above, the following effects can be obtained.
(9) The bubble B that has flowed in the direction opposite to the gravity direction g along with the outflow of the ink L from the outlet 332 of the ink introduction path 33 reaches the region on the opposite side to the gravity direction g of the bubble storage unit 324. The bubbles B gather at the top of the convex shape, move away from the ink supply path 14, and are difficult to move from the top of the convex shape. Accordingly, it is possible to obtain the ink jet recording head 103 in which the invasion of the bubbles B into the ink supply path 14 is further suppressed and the ejection failure of the ink L is further reduced.

(Third embodiment)
Hereinafter, the ink jet recording head 2 in the present embodiment will be described in detail with reference to FIG.
FIG. 9 is a schematic sectional view of the ink jet recording head 2.
In FIG. 9, the ink jet recording head 2 includes an actuator unit 110, a flow path unit 120, and a case 130 as pressure generating means. The flow path unit 120 and the case 130 are joined.

The actuator unit 110 includes a piezoelectric element 111 and an elastic plate 112.
The piezoelectric element 111 is inserted into the storage chamber 131 of the case 130 so as to face the pressure chamber 123 formed in the flow path unit 120 with the elastic plate 112 interposed therebetween, and is fixed to the fixing substrate 132.
The piezoelectric element 111 is connected to the recording head unit 1 </ b> A or 1 </ b> B shown in FIG. 1 by the flexible cable 9, and expands and contracts toward the elastic plate 112 when a voltage is applied, thereby changing the volume of the pressure chamber 123.

The elastic plate 112 has a two-layer structure of an elastic film 113 made of a polymer film such as PPS (polyphenylene sulfite) or polyimide having a thickness of 2 to 10 μm and a stainless steel plate 114 having a thickness of several tens of μm.
The portion of the elastic plate 112 corresponding to the pressure chamber 123 includes an island portion 115 for abutting and fixing the piezoelectric element 111 obtained by etching the stainless steel plate 114 and an elastic film 113 on which the island portion 115 is not formed. A thin film portion 116.
The island 115 is displaced by the expansion and contraction of the piezoelectric element 111, the thin film 116 made of the elastic film 113 is deformed, and the volume of the pressure chamber 123 changes.

  The flow path unit 120 is configured by laminating a nozzle plate 121 having a plurality of nozzle openings 1210 and an elastic plate 112 having a function as a sealing plate on both sides with a flow path forming substrate 122 interposed therebetween. Yes.

  In the flow path forming substrate 122, a plurality of pressure chambers 123 that communicate with the nozzle openings 1210 and are arranged across the pressure chamber partition walls 126, a manifold 124A that stores ink L to be supplied to each pressure chamber 123, and An ink supply path 125 and the like communicating between the manifold 124A and each pressure chamber 123 are formed by partitioning by a partition wall.

  A silicon wafer is used as the flow path forming substrate 122, and a part of the manifold 124A is formed as a through hole by anisotropic full etching, and the pressure chamber 123 and the ink supply path 125 are formed as concave parts by anisotropic half etching. . An ink supply path 125 is connected to one end of the pressure chamber 123, and a nozzle opening 1210 is located near the end opposite to the ink supply path 125.

  Note that the flow path forming substrate 122 can be made of a metal or glass member that can be etched and has corrosion resistance. Moreover, you may comprise by laminating | stacking the etching film which decomposed | disassembled into several layers in the thickness direction and formed the through-hole corresponding to the through-hole of each layer.

The case 130 is formed with a manifold 124 </ b> B constituting the manifold 124 in communication with the ink introduction path 133 communicating with the cartridges 2 </ b> A and 2 </ b> B shown in FIG. 1 and the manifold 124 </ b> A formed on the flow path forming substrate 122.
The ink L is introduced from the inlet 1331 of the ink introduction path 133 toward the gravity direction g. An outlet 1332 of the ink introduction path 133 is formed in the manifold 124B. Here, the ink introduction path 133 has a J-shaped tube shape as in the first and second embodiments. The manifold 124B includes a bubble storage part 1242.
The bubble storage part 1242 is located near the surface 1241 in the direction opposite to the gravity direction g of the manifold 124B.

  The ink jet recording head 2 supplies the ink L to the manifold 124 from the cartridges 2 </ b> A and 2 </ b> B shown in FIG. 1, supplies the ink L from the manifold 124 into each pressure chamber 123, and extends the piezoelectric element 111, thereby 115 is pressed to pressurize the inside of the pressure chamber 123, and the ink L is ejected from the nozzle opening 1210 by this pressure.

According to the present embodiment described above, the following effects can be obtained.
(10) Since the ink L flowing through the ink introduction path 133 flows out from the outlet 1332 of the ink introduction path 133 in the direction opposite to the gravitational direction g, the bubbles B generated or entered until the outlet 1332 of the ink introduction path 133 are It rides on the flow of the ink L and heads toward the bubble reservoir 1242 formed in the direction opposite to the gravity direction g. In addition, the bubble B is directed in the direction opposite to the gravity direction g due to the buoyancy acting in the direction opposite to the gravity direction g. The bubbles B that have reached the bubble storage unit 1242 are combined with each other to form a larger bubble B or space, and are less likely to be taken into the ink L. Accordingly, it is possible to suppress the intrusion of the bubbles B into the pressure chamber 123 via the ink supply path 125 communicating with the pressure chamber 123 from the manifold 124, and the pressure in the pressure chamber 123 is increased by the actuator unit 110, and the ink is discharged from the nozzle opening 1210. When ejecting L, the pressure loss due to the bubbles B in the pressure chamber 123 is reduced, and the ink jet recording head 2 with reduced ejection failure of the ink L can be obtained.

While the embodiment and the modification have been described above, the basic configuration is not limited to that described above.
For example, the shape of the ink introduction paths 33 and 133 may be any shape as long as the introduced ink L flows out in the direction opposite to the gravity direction g at the outlets 332 and 1332. For example, a tube having a cross-sectional shape different from a circle such as a rectangle or a triangle may be used.

Further, the ink introduction paths 33 and 133 may be formed at two or more locations, or the manifold 400 may be composed of two or more common liquid chambers.
The shape of the surfaces 321, 323, 1241 of the bubble reservoirs 322, 324, 1242 is such that the region opposite to the gravity direction g of the bubble reservoirs 322, 324, 1242 is convex in the direction opposite to the gravity direction g If it has, it may be not only a plane but a curved surface. For example, it may be a spherical surface.

  Further, as a pressure generating means, a heating element is arranged in the pressure chamber, and a liquid droplet is discharged from the nozzle opening by a bubble generated by heat generation of the heating element, or static electricity is generated between the diaphragm and the electrode. Alternatively, a so-called electrostatic actuator that deforms the diaphragm by electrostatic force and discharges droplets from the nozzle openings may be used.

  The ink jet recording heads 1, 2, 101, 102, and 103 have been described as an example of the liquid ejecting head. However, as other liquid ejecting heads, for example, colors used for manufacturing a color filter such as a liquid crystal display. Examples thereof include a material ejection head, an organic EL display, an electrode material ejection head used for electrode formation such as an FED (field emission display), and a bio-organic matter ejection head used for biochip production.

  1, 2, 101, 102, 103... Inkjet recording head as a liquid ejecting head, 12, 123... Pressure chamber, 21, 1210... Nozzle opening, 14, 125. 133: Ink introduction path as a liquid introduction path, 100: Actuator as pressure generation means, 110: Actuator unit as pressure generation means, 124, 200, 400 ... Manifold, 322, 324, 1242 ... Bubble storage section, 332 , 352, 1332 ... outlet, 410 ... first common liquid chamber, 420 ... second common liquid chamber, 430 ... communication path, 1000 ... ink jet recording apparatus as liquid ejecting apparatus, L ... ink as liquid.

Claims (6)

A pressure chamber communicating with a nozzle opening for ejecting liquid;
Pressure generating means for changing the pressure in the pressure chamber;
A manifold that is a common liquid chamber communicating with the plurality of pressure chambers;
A liquid supply path communicating the plurality of pressure chambers and the manifold;
A liquid introduction path for supplying the liquid to the manifold;
A bubble reservoir formed in the manifold and positioned in a direction opposite to the gravitational direction from the liquid introduction path;
An outlet of the liquid introduction path formed in the manifold and allowing the liquid to flow out from the liquid supply path to the manifold;
Equipped with a,
The outlet of the liquid introduction path is disposed in the manifold in a direction opposite to the gravitational direction than the liquid supply path, and allows the liquid to flow out from the manifold in a direction opposite to the gravitational direction. A liquid ejecting head. The said manifold has the bottom face arrange | positioned in the direction opposite to a gravitational direction from the said liquid supply path, The said exit of the said liquid introduction path is provided in this bottom face. Liquid jet head. The liquid ejecting head according to claim 1, wherein
The manifold has a first common liquid chamber and a second common liquid chamber,
The first common liquid chamber communicates with the pressure chamber via the liquid supply path,
In the second common liquid chamber, the bubble storage portion and the outlet are formed,
A liquid ejecting head, comprising: a communication path that communicates the first common liquid chamber and the second common liquid chamber. The liquid ejecting head according to claim 3,
The liquid ejecting head, wherein the outlet is formed in a direction opposite to a gravitational direction from the communication path. In the liquid jet head according to any one of claims 1 to 4,
The liquid jet head is characterized in that a region on the opposite side to the gravity direction of the bubble reservoir has a convex shape in a direction opposite to the gravity direction. A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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