JP2018099822A - Liquid injection head and liquid injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid injection head capable of removing air bubbles entering pressure chambers and discharging the air bubbles in manifolds to the outside, and a liquid injection device.SOLUTION: A liquid injection head comprises: a flow passage formation substrate on which a plurality of pressure generating chambers communicating with nozzle openings discharging liquid is formed side-by-side in a first direction X; and a communication member 15 having a flow passage causing manifolds 17 and 18 commonly communicating with the plurality of pressure generating chambers to communicate with the pressure generating chambers. The flow passage of the communication member includes: a plurality of supply passages 19 communicating with each of the pressure generating chambers; and a communication flow passage constituting at least a part of the manifolds while communicating with the plurality of supply passages. At a supply passage side of the communication flow passage, a plurality of communication narrow passages 181 is provided. An open width in the first direction of opening at an opposite side to a supply passage side of each communication narrow passage is less than a pitch of each supply passage. The liquid injection head comprises a flow generating mechanism 110 generating flow of the liquid in the first direction in the communication flow passage at an opposite side to the supply passage side of each communication narrow passage.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus, and more particularly to an ink jet recording head and an ink jet recording apparatus that eject ink as a liquid.

  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.

  The ink jet recording head includes a manifold common to a plurality of nozzle openings, and ink is supplied to the manifold from an ink supply means such as an ink cartridge. The ink may contain bubbles and may enter the pressure chamber from the manifold.

  Such bubbles are mainly generated when the ink cartridge is replaced or leaching out from the adhesive that joins the members that define the flow path, but the generated bubbles are generated in the filter immediately downstream of the ink cartridge. Some are trapped but may enter the pressure chamber from the manifold. In order to discharge the air bubbles inside the manifold and the pressure chamber to the outside, for example, the air bubbles must be sucked together with the ink from the nozzle opening side at a negative pressure. This increases the consumption of ink not used for printing. There is a problem that it ends up.

  In the liquid ejecting head described above, in order to discharge the air bubbles stored in the air bubble storage portion of the manifold to the outside, for example, the air bubbles must be sucked together with the ink from the nozzle opening side with a negative pressure. For this reason, the consumption of the ink which is not used for printing will increase.

  On the other hand, a pressure chamber forming substrate in which a plurality of pressure generation chambers are formed, and a communication substrate in which a concave portion constituting at least a part of a common liquid chamber (also referred to as a manifold) communicating in common with the plurality of pressure generation chambers is formed. And a concave portion is provided on the side of the communication substrate opposite to the pressure chamber forming substrate, and a supply channel that communicates the concave portion and each pressure generating chamber is provided through the communication substrate along the stacking direction. Has been proposed (see, for example, Patent Document 1).

JP 2014-037133 A

  However, even in the structure described above, there is a problem of bubbles entering the pressure chamber, and in order to discharge such bubbles to the outside, the bubbles must be sucked together with the ink from the nozzle opening side at a negative pressure. There is a problem that consumption of ink not used for printing increases.

  Such a problem exists not only in an ink jet recording head but also in a liquid ejecting head that ejects liquid other than ink.

  In view of such circumstances, it is an object of the present invention to provide a liquid ejecting head and a liquid ejecting apparatus that can eliminate bubbles entering the pressure chamber and discharge the bubbles in the manifold to the outside.

  An aspect of the present invention that solves the above problem is common to a plurality of pressure generating chambers and a flow path forming substrate in which a plurality of pressure generating chambers communicating with nozzle openings for discharging liquid are formed side by side in the first direction. And a communication member having a flow path for communicating the pressure generation chamber, and the flow path of the communication member includes a plurality of supply paths communicating with each of the pressure generation chambers, and A communication channel that communicates with a plurality of supply channels and forms at least a part of the manifold, and a plurality of communication narrow channels are provided on the supply channel side of the communication channel, The opening width in the first direction of the opening on the side opposite to the supply path is smaller than the pitch of the supply path, and the first communication channel on the side of the communication narrow path opposite to the supply path is in the first communication path. Generated liquid flow along the direction A liquid-jet head characterized by comprising that flow generation mechanism.

  In this aspect, since the opening on the side opposite to the supply channel of the communication narrow path has a small opening width in the first direction, bubbles having a diameter larger than the opening width are trapped in the opening and enter the pressure generation chamber. There is nothing. Further, the bubbles trapped in the opening can be discharged to the outside from the end in the first direction by the liquid flow along the first direction formed by the flow generation mechanism.

  Here, it is preferable that the length of the opening of the communication narrow path in the direction intersecting the first direction is larger than the opening width of the opening in the first direction. According to this, it is possible to prevent clogging when bubbles are trapped in the opening of the communication narrow path.

  Moreover, the said communication narrow path is provided between the some wall which protruded between the said supply paths, and was arranged in parallel with the said 1st direction, for example. According to this, the gap between the walls becomes a communication narrow path, and bubbles are trapped by the opening formed between the adjacent walls.

  Further, the wall protrudes partway in the thickness direction of the communication member, and the opening on the side opposite to the supply path of the communication narrow path is in the thickness direction of the communication member of the adjacent wall And an end surface extending in the direction of the surface of the communicating member. According to this, since the communication narrow path is defined between the walls, and the opening of the communication narrow path is open in two orthogonal directions, even if the opening between one end face is closed, the other The liquid can be supplied to the supply path through the opening between the end faces, and the flow path resistance does not increase greatly.

  Moreover, it is preferable that the said communication narrow path is provided between the several pillars which protruded in the thickness direction of the said communication member in the said communication flow path, and was arranged in parallel in the said 1st direction. According to this, bubbles having a diameter larger than the opening width are trapped at the opening portion of the communication narrow channel between the columns and do not enter the pressure generating chamber, and the opening portion of the communication member of the communication flow path Since it has dimensions in the thickness direction, even if a part of the opening is closed, the liquid can be supplied to the supply path through the other part of the opening, so the flow resistance is greatly increased. Never do.

  In addition, the column is provided on the supply path side with respect to, for example, half the length of the communication member in the thickness direction of the communication member and the second direction orthogonal to the first direction. According to this, the communication flow path is divided by the pillars, and the supply path side also becomes a common flow path communicating with the plurality of supply paths, but bubbles having a diameter larger than the opening width are trapped by the openings between the pillars and supplied. Air bubbles do not enter the communication channel on the road side.

  Moreover, it is preferable that the dimension of the said 1st direction of the said opening part on the opposite side to the said supply path of the said communication narrow path is 30 micrometers or less. According to this, bubbles having a diameter of 30 μm are trapped by the opening portion of the communication narrow passage, and generally, the bubbles below this are naturally annihilated, so that the problem of bubbles on the downstream side of the communication narrow passage is solved.

  Moreover, it is preferable that the dimension of the said 1st direction of the said opening part on the opposite side to the said supply path of the said communication narrow path is a dimension of the bubble which extinguishes naturally in the said liquid. According to this, even if there is a bubble passing through the communication narrow path, it will naturally disappear thereafter, so the problem of the bubble on the downstream side of the communication narrow path is solved.

  The flow generation mechanism is, for example, a circulation mechanism that circulates the liquid in the manifold. According to this, bubbles trapped at the opening of the communication narrow path can be discharged to the outside by using a circulation mechanism provided for the purpose of preventing precipitation of components in the liquid.

  Another aspect of the invention is a liquid ejecting apparatus including the liquid ejecting head according to the aspect.

  In this aspect, the manifold and the supply path that communicates with the pressure generation chamber communicate with each other only through the communication narrow path, and the opening on the side opposite to the supply path of the communication narrow path is the opening in the first direction. Since the width is small, bubbles having a diameter larger than the opening width are trapped in the opening, and a liquid ejecting apparatus that does not enter the pressure generating chamber is realized. Further, the bubbles trapped in the opening can be discharged to the outside from the end in the first direction by the liquid flow along the first direction formed by the flow generation mechanism.

FIG. 2 is an exploded perspective view of a recording head according to Embodiment 1 of the invention. It is a top view of the flow path formation board concerning Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view of the recording head according to the first embodiment of the invention. FIG. 2 is an enlarged cross-sectional view of a main part of the recording head according to Embodiment 1 of the invention. It is a top view of the communicating board concerning Embodiment 1 of the present invention. It is the perspective view which notched the principal part of the communicating plate which concerns on Embodiment 1 of this invention. It is principal part sectional drawing explaining the effect | action which concerns on Embodiment 1 of this invention. It is a figure which shows the behavior of the bubble in a liquid. It is a top view of the communicating board concerning Embodiment 2 of the present invention. It is the perspective view which notched the principal part of the communicating plate which concerns on Embodiment 2 of this invention. It is principal part sectional drawing explaining the effect | action which concerns on Embodiment 2 of this invention. 1 is a schematic diagram of a recording apparatus according to an embodiment of the present invention.

  Hereinafter, the present invention will be described in detail based on embodiments.

(Embodiment 1)
FIG. 1 is an exploded perspective view of an ink jet recording head that is a liquid ejecting head according to Embodiment 1 of the present invention, FIG. 2 is a plan view of a main part of a flow path forming substrate of the recording head, and FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. 2, FIG. 4 is an enlarged view of the main part of FIG. 3, FIG. 5 is a plan view of the communication plate, and FIG. It is the perspective view which notched the part.

  As shown in the figure, the flow path forming substrate 10 constituting the ink jet recording head 1 (hereinafter also simply referred to as the recording head 1) of the present embodiment has a plurality of partition walls by anisotropic etching from one side. The pressure generating chambers 12 partitioned by 11 are juxtaposed along the direction in which a plurality of nozzle openings 21 for discharging ink are juxtaposed. Hereinafter, this direction is referred to as a direction in which the pressure generating chambers 12 are arranged side by side or a first direction X. Further, the flow path forming substrate 10 is provided with a plurality of rows in which the pressure generation chambers 12 are arranged in parallel in the first direction X, and in this embodiment, two rows. An arrangement direction in which a plurality of rows of the pressure generating chambers 12 are arranged is hereinafter referred to as a second direction Y. Furthermore, a direction orthogonal to both the first direction X and the second direction Y is referred to as a third direction Z. In detail, the case member 40 side described later is referred to as a Z1 side, and the nozzle plate 20 side is referred to as a Z2 side. The first direction X, the second direction Y, and the third direction Z are directions orthogonal to each other, but are not particularly limited thereto, and may be directions that intersect at an angle other than orthogonal. .

  A communication plate 15 as a communication member and a nozzle plate 20 are sequentially stacked on the Z2 side surface side of the flow path forming substrate 10. The communication member may be formed by stacking a plurality of communication plates.

  As shown in FIGS. 3 and 4, the communication plate 15 is provided with a nozzle communication path 16 that communicates the pressure generation chamber 12 and the nozzle opening 21. The communication plate 15 has a larger area than the flow path forming substrate 10, and the nozzle plate 20 has a smaller area than the flow path forming substrate 10. By providing the communication plate 15 in this manner, the nozzle opening 21 of the nozzle plate 20 and the pressure generating chamber 12 can be separated from each other, so that the ink in the pressure generating chamber 12 is contained in the ink generated by the ink near the nozzle opening 21. Less susceptible to thickening due to moisture evaporation. Further, since the nozzle plate 20 only needs to cover the opening of the nozzle communication passage 16 that communicates the pressure generating chamber 12 and the nozzle opening 21, the area of the nozzle plate 20 can be made relatively small, and the cost can be reduced. be able to. In the present embodiment, a surface on which the nozzle openings 21 of the nozzle plate 20 are opened and ink droplets are ejected is referred to as a liquid ejecting surface 20a.

  Further, the communication plate 15 is provided with a first manifold portion 17 that constitutes a part of the manifold 100 and a second manifold portion 18 that is a concave portion of the present embodiment.

  The first manifold portion 17 is provided through the communication plate 15 in the third direction Z. On the other hand, the second manifold portion 18 is a recess provided to open to the nozzle plate 20 side of the communication plate 15 without penetrating the communication plate 15 in the third direction Z.

  Further, the communication plate 15 is provided with a supply path 19 that communicates with one end of the pressure generation chamber 12 in the second direction Y, corresponding to each of the pressure generation chambers 12. The supply path 19 communicates the second manifold portion 18 and the pressure generation chamber 12. That is, the supply path 19 is arranged in parallel in the first direction X.

  Further, on the supply path 19 side of the second manifold portion 18, a plurality of walls 171 protruding in the middle of the thickness direction of the communication plate 15 between the supply paths 19 are arranged in parallel in the first direction X. Yes.

The flow path between the walls 171 is a communication narrow channel 181 that allows the second manifold portion 18 and the supply channel 19 to communicate with each other. The communication narrow channel 181 has an opening 182 opposite to the supply channel 19. The opening width d ₁ that is the dimension in the first direction X is smaller than the pitch d ₂ of the supply path 19 and is, for example, about 30 μm.

Here, the opening 182 is formed continuously between the end surface 172 on the second direction Y side of the adjacent wall 171 and the end surface 173 on the Z2 side that is continuous therewith, and the opening 182 is open at any location. The width d ₁ is smaller than the pitch d ₂ of the supply path 19 and is, for example, about 30 μm. The direction of the length crossing the opening width d ₁ which is the dimension in the direction intersecting the first direction X of the opening 182, i.e., the length in the direction in this embodiment perpendicular to the opening width d ₁ is The dimension L _{1 in} the third direction Z of the communication plate 15 on the end face 172 and the dimension in the second direction Y of the end face 173 are the sum of L ₂ (L ₁ + L ₂ ), which is sufficient.

  Further, in this embodiment, the communication narrow channel 181 communicates with the supply channel 19 as it is, and is an individual channel that communicates with the second manifold portion 18 that is a common channel. The second manifold portion 18 is configured to communicate with only the communication narrow path 181.

Therefore, by providing such a communication narrow channel 181, bubbles having a diameter larger than the dimension d ₁ are trapped in the opening 182 between the end surfaces 172 and 173 of the wall 171, and pressure is generated through the supply channel 19. It does not enter the chamber 12.

In addition, the length (L ₁ + L ₂ ) of the opening 182 of the communication narrow path 181 is significantly larger than the dimension d ₁ , so that bubbles are trapped between the end surfaces 172 and 173 of the wall 171 and the opening 182. Even if the liquid is blocked, the entire opening 182 is not blocked, and the liquid flow is ensured through the non-blocked opening 182, so that the discharge of the liquid is not hindered. Further, as will be described in detail later, the movement of the bubbles trapped in a part of the opening 182 is restricted by the flow of liquid through the other part of the opening 182, and the bubbles are trapped at the end of the opening 182. There is also an advantage that it becomes easier to collect bubbles later. Here, the length of the opening 182 _(L 1 + L ₂₎ is significantly larger intent compared to the dimension _{d 1} is as described above, is remarkably large, the length of the opening 182 _(L 1 + L ₂ ) Is equal to or larger than the dimension in the thickness direction of the communication member. In the present embodiment, L ₁ is smaller than the thickness of the communication plate, but L ₂ is sufficiently larger than the thickness, and as a whole is larger than the thickness.

  Here, in this embodiment, the communication plate 15 is made of a silicon substrate (silicon single crystal substrate), and the wall 171 is formed by anisotropic etching (wet etching) using at least the second manifold portion 18 using an alkaline solution such as KOH. ) Can be formed by devising an etching pattern. Of course, it may be formed by dry etching or the like.

  The nozzle plate 20 joined to the Z2 side of the communication plate 15 is formed with nozzle openings 21 communicating with the pressure generation chambers 12 via the nozzle communication passages 16. That is, nozzle openings 21 that eject the same type of liquid (ink) are juxtaposed in the first direction X, and the rows of nozzle openings 21 juxtaposed in the first direction X are in the second direction. Two rows are formed in Y.

  On the other hand, a diaphragm 50 is formed on the surface of the flow path forming substrate 10 on the Z1 side. In the present embodiment, an elastic film 51 made of silicon oxide provided on the flow path forming substrate 10 side and an insulator film 52 made of zirconium oxide provided on the elastic film 51 are provided as the diaphragm 50. I made it. The liquid flow path such as the pressure generation chamber 12 is formed by anisotropically etching the flow path forming substrate 10 from one side (the side where the nozzle plate 20 is bonded). The other surface is defined by an elastic film 51.

  In addition, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are laminated on the diaphragm 50 of the flow path forming substrate 10 by film formation and lithography to form the piezoelectric actuator 300. In the present embodiment, the piezoelectric actuator 300 serves as a pressure generating unit that causes a pressure change in the ink in the pressure generating chamber 12. Here, the piezoelectric actuator 300 is also referred to as a piezoelectric element 300 and refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. A portion where piezoelectric distortion occurs in the piezoelectric layer 70 when a voltage is applied between the first electrode 60 and the second electrode 80 is referred to as an active portion 310. In this embodiment, as will be described in detail later, an active portion 310 is formed for each pressure generation chamber 12. That is, a plurality of active portions 310 are formed on the flow path forming substrate 10. In general, any one electrode of the active part 310 is configured as a common electrode common to the plurality of active parts 310, and the other electrode is configured as an individual electrode independent for each active part 310. In the present embodiment, the first electrode 60 is an individual electrode and the second electrode 80 is a common electrode, but this may be reversed. In the above-described example, the diaphragm 50 and the first electrode 60 act as a diaphragm. However, the present invention is not limited to this. For example, the diaphragm 50 is not provided, and only the first electrode 60 vibrates. You may make it act as a board. Further, the piezoelectric actuator 300 itself may substantially serve as a diaphragm.

  Here, the first electrode 60 constituting the piezoelectric actuator 300 of the present embodiment is separated for each pressure generation chamber 12, and an independent electrode is provided for each active part 310 that is a substantial driving part of the piezoelectric actuator 300. Configure. The first electrode 60 is formed with a width narrower than the width of the pressure generation chamber 12 in the second direction Y of the pressure generation chamber 12. That is, in the first direction X of the pressure generation chamber 12, the end portion of the first electrode 60 is located inside the region facing the pressure generation chamber 12. In the second direction Y, both end portions of the first electrode 60 are extended to the outside of the pressure generation chamber 12.

  The piezoelectric layer 70 is continuously provided in the first direction X so that the second direction Y has a predetermined width. The width of the piezoelectric layer 70 in the second direction Y is wider than the length of the pressure generation chamber 12 in the second direction Y. Therefore, in the second direction Y of the pressure generation chamber 12, the piezoelectric layer 70 is provided to the outside of the pressure generation chamber 12.

  In the second direction Y of the pressure generating chamber 12, the end of the piezoelectric layer 70 on the ink supply path side is located outside the end of the first electrode 60. That is, the end portion of the first electrode 60 is covered with the piezoelectric layer 70. The end of the piezoelectric layer 70 on the nozzle opening 21 side is located on the inner side (pressure generation chamber 12 side) of the end of the first electrode 60, and the end of the first electrode 60 on the nozzle opening 21 side. The portion is not covered with the piezoelectric layer 70.

The piezoelectric layer 70 is made of a piezoelectric material of the oxide having a polarization structure formed on the first electrode 60, for example, it may consist of a perovskite oxide represented by the general formula ABO _3, lead containing lead For example, a lead-based piezoelectric material or a lead-free piezoelectric material containing no lead can be used.

  In such a piezoelectric layer 70, recesses 71 corresponding to the respective partition walls are formed. The width of the recess 71 in the first direction X is substantially the same as or wider than the width of each partition wall in the first direction. As a result, the rigidity of the portion (the so-called arm portion of the diaphragm 50) that opposes the end of the pressure generation chamber 12 of the diaphragm 50 in the second direction Y is suppressed, so that the piezoelectric actuator 300 can be displaced favorably. it can.

  The second electrode 80 is provided on the opposite surface side of the piezoelectric layer 70 from the first electrode 60 and constitutes a common electrode common to the plurality of active portions 310. Further, the second electrode 80 may or may not be provided on the inner surface of the recess 71, that is, on the side surface of the recess 71 of the piezoelectric layer 70.

  Further, an individual wiring 91 that is a lead-out wiring is led out from the first electrode 60 of the piezoelectric actuator 300. Further, from the second electrode 80, a common wiring 92 that is a lead-out wiring is drawn out. Further, the flexible cable 120 is connected to the extended ends of the individual wiring 91 and the common wiring 92 opposite to the ends connected to the piezoelectric actuator 300. The flexible cable 120 is a flexible wiring board, and in this embodiment, a drive circuit 121 that is a drive element is mounted.

  A protective substrate 30 having substantially the same size as the flow path forming substrate 10 is bonded to the surface of the flow path forming substrate 10 on the Z1 side. The protective substrate 30 has a holding portion 31 that is a space for protecting the piezoelectric actuator 300. Two holding portions 31 are formed side by side in the second direction Y between the rows of piezoelectric actuators 300 arranged in parallel in the first direction X. Further, the protective substrate 30 is provided with a through hole 32 penetrating in the third direction Z between two holding portions 31 arranged in parallel in the second direction Y. The ends of the individual wires 91 and the common wires 92 drawn out from the electrodes of the piezoelectric actuator 300 are extended so as to be exposed in the through holes 32, and the individual wires 91 and the common wires 92 and the flexible cable 120 pass through. The holes 32 are electrically connected. In addition, the connection method of the individual wiring 91 and the common wiring 92, and the flexible cable 120 is not specifically limited, For example, soldering, brazing, etc., eutectic bonding, welding, conductive including conductive particles Adhesive (ACP, ACF), non-conductive adhesive (NCP, NCF) and the like.

  On the protective substrate 30, a case member 40 that fixes the manifold 100 communicating with the plurality of pressure generating chambers 12 together with the flow path forming substrate 10 is fixed. The case member 40 has substantially the same shape as the communication plate 15 described above in a plan view, and is bonded to the protective substrate 30 and is also bonded to the communication plate 15 described above. Specifically, the case member 40 has a recess 41 having a depth in which the flow path forming substrate 10 and the protective substrate 30 are accommodated on the protective substrate 30 side. The concave portion 41 has an opening area larger than the surface of the protective substrate 30 bonded to the flow path forming substrate 10. The opening surface on the nozzle plate 20 side of the recess 41 is sealed by the communication plate 15 in a state where the flow path forming substrate 10 and the like are accommodated in the recess 41. As a result, the third manifold portion 42 is defined by the case member 40 and the flow path forming substrate 10 on the outer periphery of the flow path forming substrate 10. Then, the first manifold portion 17 and the second manifold portion 18 provided on the communication plate 15, and the third manifold portion 42 defined by the case member 40 and the flow path forming substrate 10, the manifold of this embodiment. 100 is configured. The manifold 100 is provided continuously in the first direction X, which is the direction in which the pressure generating chambers 12 are arranged, and the supply path 19 that communicates each pressure generating chamber 12 and the manifold 100 has a first passage. They are juxtaposed in the direction X.

  A compliance substrate 45 is provided on the Z2 side surface of the communication plate 15 where the first manifold portion 17 and the second manifold portion 18 open. The compliance substrate 45 seals the openings of the first manifold portion 17 and the second manifold portion 18 on the liquid ejection surface 20a side. In this embodiment, the compliance substrate 45 includes a sealing film 46 made of a flexible thin film and a fixed substrate 47 made of a hard material such as metal. Since the region facing the manifold 100 of the fixed substrate 47 is an opening 48 that is completely removed in the thickness direction, one surface of the manifold 100 is sealed only with a flexible sealing film 46. The compliance portion 49 is a flexible portion.

  The case member 40 is provided with an introduction path 44 that communicates with the manifold 100 and supplies ink to each manifold 100. The case member 40 is provided with a connection port 43 through which the flexible cable 120 is inserted in communication with the through hole 32 of the protective substrate 30.

  Further, in the present embodiment, as shown in FIG. 5, the circulation channel 110 and the circulation channel 110 are used as flow generation means for generating a liquid flow along the first direction X in the second manifold portion 18. A pump 111 provided in the middle is provided. The circulation flow path 110 is formed by, for example, a flexible tube connected to a circulation port 151 provided in the communication plate 15, and is supplied to the liquid in the second manifold portion 18 by the pump 111. Configured to form a flow from top to bottom. Further, on the downstream side of the pump 111, liquid storage means for temporarily storing liquid is provided in order to remove bubbles from the circulating liquid. The liquid flow in the second manifold portion 18 is for removing bubbles trapped in the opening 182 of the communication narrow channel 181 by moving them in the end direction in the first direction X. For this reason, the circulation port 151 is preferably provided so as to open in the vicinity of the opening 182 of the communication narrow narrow path 181 of the second manifold portion 18.

  The structure of the flow generation mechanism including the circulation flow path 110 and the pump 111 is not limited to this, and may be provided inside the communication plate 15 or on a substrate stacked separately from the communication plate 15. The configuration is not particularly limited. In this case, instead of the liquid storage means 112, a structure such as a bubble reservoir can be provided to return the liquid from which the bubbles have been removed.

  Furthermore, conventionally, a head having a circulation mechanism that circulates the liquid in the reservoir is known as a measure for preventing the increase in viscosity due to drying and evaporation of the liquid and the prevention of precipitation of easily precipitated components in the liquid. Such a conventionally known circulation mechanism can also be employed as the flow generation mechanism of the present invention.

  In the recording head 1 described above, when ink is ejected, the ink is taken in from the introduction path 44 and the inside of the flow path is filled with ink from the manifold 100 to the nozzle opening 21. Thereafter, in accordance with a signal from the drive circuit 121, a voltage is applied to each active portion 310 corresponding to the pressure generating chamber 12, so that the diaphragm 50 is bent and deformed together with the active portion 310. As a result, the pressure in the pressure generating chamber 12 is increased and ink droplets are ejected from the predetermined nozzle openings 21.

  The operation and effect of the present invention in such a recording head 1 will be described in more detail with reference to FIGS.

In the present embodiment, a plurality of walls 171 protruding in the middle of the thickness direction of the communication plate 15 between the supply paths 19 on the supply path 19 side of the second manifold portion 18 are arranged in parallel in the first direction X. Has been. The flow path between the walls 171 becomes the communication narrow path 181, and the dimension d _{1 in} the first direction X of the opening 182 on the side opposite to the supply path 19 of the communication narrow path 181 is the pitch d of the supply path 19. _It is smaller than ₂ , for example, about 30 μm. In addition, each supply path 19 and the second manifold portion 18 are configured to communicate with each other only through the communication narrow path 181.

Therefore, by providing such a communication narrow channel 181, bubbles having a diameter larger than the opening width d ₁ are trapped in the opening 182 between the end surfaces 172 and 173 of the wall 171, and the pressure is passed through the supply channel 19. It does not enter the generation chamber 12.

Further, since the length (L ₁ + L ₂ ) of the opening 182 of the communication narrow channel 181 is significantly larger than the opening width d ₁ , bubbles are trapped between the end surfaces 172 and 173 of the wall 171 and the opening Even if 182 is blocked, the entire opening 182 is not blocked.

  FIG. 7 schematically shows this state, and the trapped bubbles A1 and A2 move to the positions farthest from the end surfaces 172 between the end surfaces 172 and the end surfaces 173, and grow. Since the opening 182 between them is sufficiently open, the liquid flow is not hindered.

  In addition, the bubbles A1 and A2 trapped in a part of the opening 182 in this manner are the liquids along the first direction X formed by the circulation flow path 110 and the pump 111 provided as the flow generation means. Due to the flow, the bubbles are removed by the liquid storage means 112 via the circulation channel 110 and returned to the original state.

With such a configuration, by providing the communication narrow channel 181, bubbles having a diameter larger than the opening width d ₁ of the opening 182 are trapped in the opening 182 and enter the pressure generation chamber 12 through the supply channel 19. There is nothing.

  Therefore, unlike the prior art, there is no need to perform a suction operation for discharging the bubbles that have entered the pressure generating chamber 12 to the outside, and the consumption of ink that is not used for printing is significantly reduced.

   In addition, the bubbles trapped at the opening 182 are discharged to the outside through the circulation channel 110, and are returned after the bubbles are removed by the liquid storage means 112. Therefore, a suction operation for discharging the trapped bubbles is also performed. There is an advantage that there is no need to use a wasteful liquid.

In this embodiment, the opening width d ₁ of the opening 182 of the communicating narrow passage 181 was about 30μm, in the water-based ink, the following bubble 30μm is because been found when natural mortality with time.

FIG. 8 shows the behavior of bubbles in a liquid such as ink. As shown in FIG. 8, it is known that bubbles below a certain threshold S become smaller with time and disappear at the end, but bubbles having a size exceeding the threshold S become larger in diameter with time. This differs depending on the type of the liquid, and the threshold S in the liquid to be used can be grasped by measuring the behavior of the bubbles. When the threshold value S was measured with a water-based ink containing a dye, the threshold value S was approximately above 30 μm. Therefore, if the opening width d ₁ is about 30 μm, even if there is a bubble passing through the opening width d ₁ , the bubble disappears naturally, so that no bubble exists in the pressure generation chamber 12 or the like.

(Embodiment 2)
9 to 11 are a plan view, a main part perspective view, and a main part cross-sectional view of a communication plate according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

In this embodiment, a column 271 is provided instead of the wall 171. The columns 271 are juxtaposed in the first direction X in the vicinity of the supply path 19 in the second manifold section 18, on the first manifold section 17 side, at a position corresponding to the space between the supply paths 19. Further, the pillars 271 may have a third identical dimensions L ₃ and the dimension of the direction Z of the second manifold portion 18, the distance between the first direction X, i.e., provided so that the opening width is d ₁ ing. Furthermore, the columns 271 are arranged in parallel along the first direction X of the second manifold portion 18, and the second manifold portion 18 is supplied to the first manifold portion 17 side by the arranged columns 271. The road 19 is divided into two parts. The second manifold section 18 on the first manifold side and the second manifold section 18 on the supply path 19 side are configured to communicate with each other only through the communication narrow path 181 between the columns 271. In this configuration, the flow path 183 that is the second manifold portion 18 on the supply path 19 side is also a common flow path.

In addition, the opening width d ₁ of the opening 182 of the communication narrow channel 181 is about 30 μm as in the first embodiment, and the length of the opening 182 in the direction intersecting the first direction X, that is, the opening width d _1. as length in a direction intersecting the above, the has a dimension L _3, significantly larger than the opening width d _1, equal to the dimension length L ₃ in the thickness direction of the communication member of the opening 182 It has become.

Therefore, by providing such a communication narrow channel 181, bubbles having a diameter larger than the opening width d ₁ are trapped in the opening 182 between the end surfaces 272 of the column 271 and pass through the supply channel 19 to generate a pressure generating chamber. No twelve in.

In addition, since the length L ₃ of the opening 182 of the communication narrow path 181 is significantly larger than the opening width d ₁ , air bubbles are trapped between the end surfaces 272 of the columns 271 and a part of the opening 182 is blocked. Even if it is peeled off, the entire opening 182 is not blocked.

  FIG. 11 schematically shows this state, and the trapped bubble A3 moves to a position farthest from the supply path 19 between the end faces 272 and grows, but is a part close to the supply path 19 Since the opening 182 is sufficiently open, the liquid flow is not hindered.

  Further, the bubble A3 trapped in a part of the opening 182 in this way is caused by the flow of the liquid along the first direction X formed by the circulation flow path 110 and the pump 111 provided as the flow generation means. The point that bubbles are removed by the liquid storage means 112 via the circulation channel 110 and returned to the original state is the same as in the first embodiment.

With such a configuration, by providing the communication narrow channel 181, bubbles having a diameter larger than the opening width d ₁ of the opening 182 are trapped in the opening 182 and enter the pressure generation chamber 12 through the supply channel 19. There is nothing.

  Therefore, unlike the prior art, there is no need to perform a suction operation for discharging the bubbles that have entered the pressure generating chamber 12 to the outside, and the consumption of ink that is not used for printing is significantly reduced.

  In addition, the bubbles trapped at the opening 182 are discharged to the outside through the circulation channel 110, and are returned after the bubbles are removed by the liquid storage means 112. Therefore, a suction operation for discharging the trapped bubbles is also performed. There is an advantage that there is no need to use a wasteful liquid.

(Other embodiments)
As mentioned above, although each embodiment of this invention was described, the fundamental structure of this invention is not limited to what was mentioned above.

  For example, the wall 171 of the first embodiment has a height halfway in the third direction Z of the second manifold portion 18, but may have the same dimensions as the second manifold portion 18. In this case, the length of the opening 182 is L3 similar to that of the second embodiment, and the same effect as that of the second embodiment is achieved.

  In the above-described second embodiment, the shape, position, etc. of the column 271 are not limited to those described above. The cross-sectional shape of the column 271 is not limited to a rectangular shape, and may be a polygonal shape or a circular shape. Further, the position of the column 271 along the second direction Y is not particularly limited, but the column 271 is provided closer to the supply path 19 than half the length of the second manifold portion 18 in the second direction Y. preferable. Moreover, it is good also as a position where the trapped bubble is easy to move with the flow of a liquid from the relationship with the position which provides the circulation port 115 which connects the circulation channel 110.

  Further, the position of the column 271 along the first direction X is not particularly limited, and as described above, it is not necessary to provide between the supply paths 19, and it is also necessary to provide according to the number of supply paths 19. Absent. In any case, the second manifold section 18 on the first manifold section side and the second manifold section 18 on the supply path 19 side, which are divided by the columns 271 arranged side by side, communicate with each other. What is necessary is just to become the structure connected via only 181.

  Further, in each of the embodiments described above, the thin film piezoelectric actuator 300 has been described as the pressure generating means for causing a pressure change in the pressure generating chamber 12, but the present invention is not particularly limited thereto. For example, a green sheet is attached. It is possible to use a thick film type piezoelectric actuator formed by such a method, a longitudinal vibration type piezoelectric actuator in which piezoelectric materials and electrode forming materials are alternately stacked and expanded and contracted in the axial direction. Also, as a pressure generating means, a heating element is arranged in the pressure generating chamber, and droplets are discharged from the nozzle opening by bubbles generated by the heat generated by the heating element, or static electricity is generated between the diaphragm and the electrode. Thus, a so-called electrostatic actuator that discharges liquid droplets from the nozzle openings by deforming the diaphragm by electrostatic force can be used.

  Such a recording head 1 is mounted on an ink jet recording apparatus I. FIG. 12 is a schematic diagram illustrating an example of an ink jet recording apparatus according to the present embodiment.

  In the ink jet recording apparatus I shown in FIG. 12, the recording head 1 is provided with a cartridge 2 constituting a liquid supply means in a detachable manner, and a carriage 3 on which the recording head 1 is mounted is a carriage attached to the apparatus body 4. The shaft 5 is provided so as to be movable in the axial direction.

  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 1 is mounted is moved along the carriage shaft 5. On the other hand, the apparatus main body 4 is provided with a conveyance roller 8 as a conveyance means, and a recording sheet S which is a recording medium such as paper is conveyed by the conveyance roller 8. Note that the conveyance means for conveying the recording sheet S is not limited to the conveyance roller, and may be a belt, a drum, or the like.

  In the above-described example, the ink jet recording apparatus I has a configuration in which the cartridge 2 as the ink supply unit is mounted on the carriage 3. However, the invention is not particularly limited thereto, and for example, a liquid supply unit such as an ink tank is used. The liquid supply means and the recording head 1 may be connected to each other via a supply pipe such as a tube by being fixed to the apparatus main body 4. Further, the liquid supply means may not be mounted on the ink jet recording apparatus.

  Further, in the above-described ink jet recording apparatus I, the recording head 1 is mounted on the carriage 3 and exemplarily moves in the main scanning direction. However, the present invention is not particularly limited thereto. For example, the recording head 1 is fixed, The present invention can also be applied to a so-called line type recording apparatus that performs printing only by moving a recording sheet S such as paper in the sub-scanning direction.

  In addition, the present invention is intended for a wide range of liquid ejecting heads in general, for example, for manufacturing recording heads such as various ink jet recording heads used in image recording apparatuses such as printers, and color filters such as liquid crystal displays. The present invention can also be applied to a coloring material ejecting head, an organic EL display, an electrode material ejecting head used for forming electrodes such as an FED (field emission display), a bioorganic matter ejecting head used for biochip manufacturing, and the like. Further, although the ink jet recording apparatus I has been described as an example of the liquid ejecting apparatus, the liquid ejecting apparatus using the other liquid ejecting heads described above can also be used.

  DESCRIPTION OF SYMBOLS I ... Inkjet recording device (liquid ejecting apparatus), 1 ... Inkjet recording head (liquid ejecting head), 2 ... Cartridge, 10 ... Channel formation substrate (substrate), 11 ... Partition, 12 ... Pressure generating chamber, 15 ... Communication plate, 16 ... Nozzle communication passage, 17 ... First manifold portion, 18 ... Second manifold portion (concave portion), 19 ... Supply passage, 20 ... Nozzle plate, 21 ... Nozzle opening, 30 ... Protection substrate, 40 ... Case member 45 ... Compliance substrate 50 ... Vibration plate 60 ... First electrode 70 ... Piezoelectric layer 71 ... Recessed portion 80 ... Second electrode 91 ... Individual wiring 92 ... Common wiring 100 ... Manifold 120 ... Flexible Cable 121, drive circuit 171 wall 172 173 end face 181 communication narrow path 182 opening 271 pillar 272 end face 300 piezoelectric Position actuator (pressure generating means), 310 ... active portion

Claims (10)

A flow path forming substrate in which a plurality of pressure generating chambers communicating with a nozzle opening for discharging liquid are formed side by side in the first direction;
A communication member having a flow path communicating the manifold and the pressure generation chamber in common with a plurality of the pressure generation chambers;
Comprising
The flow path of the communication member includes a plurality of supply paths communicating with each of the pressure generation chambers, and a communication flow path communicating with the plurality of supply paths and constituting at least a part of the manifold,
A plurality of communication narrow passages are provided on the supply passage side of the communication passage, and the opening width in the first direction of the opening portion on the side opposite to the supply passage side of the communication narrow passage is the pitch of the supply passage. Smaller than
A liquid ejecting head comprising: a flow generating mechanism for generating a liquid flow along the first direction in the communication flow path on the opposite side of the communication narrow path from the supply path side.   The liquid ejecting head according to claim 1, wherein a length of the opening portion of the communication narrow path in a direction intersecting the first direction is larger than an opening width of the opening portion in the first direction. .   3. The liquid jet according to claim 1, wherein the narrow communication path is provided between a plurality of walls protruding between the supply paths and arranged in parallel in the first direction. head.   The wall protrudes partway in the thickness direction of the communication member, and the opening of the communication narrow path opposite to the supply path extends in the thickness direction of the communication member of the adjacent wall. The liquid ejecting head according to claim 3, wherein the liquid ejecting head is defined between an end face and an end face extending continuously in the surface direction of the communication member.   The communication narrow channel is provided between a plurality of pillars protruding in the thickness direction of the communication member in the communication channel and arranged in parallel in the first direction, and the supply of the communication narrow channel The liquid ejecting head according to claim 1, wherein the opening opposite to the path is defined by an end surface extending in a thickness direction of the adjacent column.   The column is provided on the supply path side with respect to a thickness direction of the communication member of the communication channel and a half of a length in a second direction orthogonal to the first direction. Item 6. The liquid jet head according to Item 5.   The liquid ejection according to any one of claims 1 to 6, wherein a dimension of the opening portion on the opposite side of the communication narrow path from the supply path is 30 µm or less. head.   The dimension of the said 1st direction of the said opening part on the opposite side to the said supply path of the said communication narrow path is a dimension of the bubble which naturally extinguishes in the said liquid. The liquid ejecting head according to claim 1.   The liquid ejecting head according to claim 1, wherein the flow generation mechanism is a circulation mechanism that circulates the liquid in the manifold.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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