JP2016128271A - Liquid spray head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid spray head which can improve a bubble discharging efficiency in a reservoir without generating stagnation in a confluence area of liquid in a case where a plurality of liquid supply ports are provided therein.SOLUTION: The liquid spray head has: pressure generating chambers 11 parallely arranged to respectively discharge inner liquid through each nozzle opening 13 by pressure variation; piezoelectric elements 17 which are arranged corresponding to the respective pressure generating chambers 11 and deformed by being supplied with driving signals so as to cause pressure variation of the liquid in the pressure generating chambers 11; and a reservoir 22 arranged over the parallely arranging direction of the pressure generating chambers 11 to communicate with the chambers. The reservoir 22 communicates with a plurality of ink introduction ports 21a and 21b, and has a wall at the opposite side of the pressure generating chambers 11 protruded in a confluence area of liquid supplied from the respective ink introduction ports 21a and 21b so as to have a throttling part 22a formed so that a width of the protrusion is smaller than widths of other portions.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus that eject liquid from nozzle openings, and is particularly useful when applied to an ink jet recording head and an ink jet recording apparatus that eject ink as liquid.

  As an ink jet recording head which is an example of a liquid ejecting head, for example, an actuator unit provided with a piezoelectric element and a pressure generating chamber, a nozzle plate provided with a nozzle opening communicating with the pressure generating chamber and discharging ink, Some have a flow path unit provided with a reservoir serving as a common ink chamber for the pressure generating chamber.

  The reservoir of such an ink jet recording head is configured such that its width becomes narrower as it moves away from the liquid inlet arranged in the center (see Patent Document 1), or the reservoir is branched to branch ports. A configuration in which the flow resistance of each branch flow path is made uniform by matching the direction of the flow (see Patent Document 2) is known. The former is designed to increase the flow rate in the area where bubbles tend to stay to prevent the bubbles from staying, and the latter is designed to simultaneously fill the pressure generating chambers with ink so that the remaining bubbles in the reservoir remain. It is devised to suppress this.

JP 2002-292868 A JP 2006-297897 A

  However, the reservoir structure as described above cannot cope with the increase in length of the ink jet recording head. That is, in the past, ink was introduced into the reservoir through a single liquid inlet provided in the central portion of the reservoir. However, in an ink jet recording head having a length exceeding 1 inch, the reservoir is also proportional. As a result, the pressure loss in the reservoir increases. In order to remove the influence of such an increase in pressure loss and ensure ink supply, it is necessary to provide two or more liquid inlets. However, in this case, there arises a new problem that the flow becomes stagnant in the ink confluence region, making it difficult to discharge the bubbles. As described above, the techniques disclosed in Patent Documents 1 and 2 cannot cope with the new problem of deterioration of bubble discharge properties caused by ink stagnation when a plurality of liquid supply ports are provided. This is because all of them are premised on the case where one reservoir is provided in one reservoir.

  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 the above-described problems of the prior art, the present invention provides a liquid ejecting head capable of improving bubble discharge performance in a reservoir without generating stagnation in a confluence region of liquid when a plurality of liquid supply ports are provided, and An object is to provide a liquid ejecting apparatus.

  An aspect of the present invention that solves the above-described problems includes a pressure generation chamber arranged in parallel to a substrate so as to discharge liquid through a nozzle opening due to pressure fluctuation, and pressure generation that causes pressure fluctuation in the liquid in the pressure generation chamber. Means and a reservoir provided on the substrate to supply the liquid to the pressure generating chamber and to form a common liquid chamber provided across the juxtaposed direction of the pressure generating chamber. The liquid is supplied from a plurality of liquid inlets, and the cross-sectional area of the reservoir in the merging area of the liquid supplied from each liquid inlet is larger than the cross-sectional area of the reservoir in a predetermined area other than the merging area. The liquid ejecting head is configured to be small.

  According to this aspect, the stagnation in the confluence region of the liquid supplied from the plurality of liquid supply ports can be removed in the narrow portion of the confluence region, so that the bubbles remaining due to the stagnation can be discharged well. . In addition, since the flow of liquid supplied to each pressure generating chamber through the reservoir can be made to be a flow that is more parallel to the longitudinal direction of each pressure generating chamber, this also ensures good bubble discharge performance. can do.

  By the way, when multiple heads or multiple reservoirs are simply arranged for lengthening, the structural strength variation of each head or multiple reservoirs, the static pressure variation of the reservoirs, and the compliance between reservoirs Crosstalk occurs due to variations and the like. However, in this embodiment, it is easy to use one common reservoir even if the head is lengthened. Therefore, the structural strength variation, the reservoir static pressure balance, and the compliance variation in the reservoir are aligned. As a result, the bubble discharge performance can be made sufficiently good while suppressing crosstalk.

  Here, the reservoir is configured to supply the liquid to the pressure generation chamber via a liquid supply port in a direction along the surface of the substrate, and the inner wall of the reservoir facing the liquid supply port in the merging region However, it can be configured to be convex toward the liquid supply port. In this case, in the liquid ejecting head of the type that supplies the liquid to the pressure generating chamber through the liquid supply port from the direction parallel to the surface direction of the substrate, the above-described operation and effect can be exhibited. The reservoir is configured to supply the liquid to the pressure generation chamber via a liquid supply port in the thickness direction of the substrate, and the pressure generation chambers are arranged in parallel with the liquid supply port interposed therebetween. Each of the inner walls of the reservoir extending in the direction can be configured to be convex toward the opposite inner walls of the reservoir in the merge region. In this case, in the liquid ejecting head of the type that supplies the liquid to the pressure generating chamber through the liquid supply port from the direction parallel to the thickness direction of the substrate, the above-described operation and effect can be exhibited. it can. In addition, the reservoir inner walls extending in the direction in which the pressure generating chambers are juxtaposed across the liquid supply port in the predetermined region are all separated from the liquid supply port by a distance larger than the diameter of the bubble that can naturally disappear. It is desirable. This is because harmful bubbles tend to grow as the distance becomes smaller.

  As described above, reducing the width can be easily realized by, for example, forming a constricted portion in the merging region. In addition, it is preferable that the throttle portion has a shape in which the width gradually decreases from the liquid inlet side in the juxtaposed direction of the pressure generating chambers toward an intermediate portion of the adjacent liquid inlet. This is because bubbles can be effectively discharged by causing the liquid flow to follow the throttle portion. Here, it is optimal that the width of the narrowed portion has a shape that gradually decreases along the streamline of the liquid. This is because the flow of the liquid becomes the smoothest, and the bubbles are discharged well accordingly.

  Further, a plurality of the throttle portions may be provided in the reservoir. In this case, a plurality of fluid merging regions can be formed to remove stagnation of fluid in each merging region. Therefore, it becomes particularly useful when the longitudinal dimension of the reservoir becomes long.

  Another aspect of the invention is a liquid ejecting apparatus including the liquid ejecting head as described above.

  According to this aspect, not only the printing speed can be increased with a long head, but also the printing quality can be improved.

FIG. 3 is a cross-sectional view of the liquid jet head according to the first embodiment of the invention. It is a top view which extracts and shows the reservoir | reserver part of FIG. It is a top view which shows the case where it does not have a throttle part with respect to the reservoir | reserver shown in FIG. FIG. 6 is a cross-sectional view of a liquid jet head according to a second embodiment of the present invention. It is a top view which extracts and shows the reservoir | reserver part of FIG. 1 is a schematic view of an ink jet recording apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view of an ink jet recording head which is an example of a liquid jet head according to the first embodiment of the present invention. As shown in the figure, an ink jet recording head 10 includes a flow path forming substrate 12 having a plurality of pressure generating chambers 11 and a nozzle plate 14 in which a plurality of nozzle openings 13 communicating with the pressure generating chambers 11 are formed. And a flow path unit 16 including a vibration plate 15 provided on the surface of the flow path forming substrate 12 opposite to the nozzle plate 14. Furthermore, a piezoelectric element unit 18 having a piezoelectric element 17 provided in a region corresponding to each pressure generating chamber 11 on the vibration plate 15, and an accommodating portion 19 that is fixed on the vibration plate 15 and accommodates the piezoelectric element unit 18. And a case head 20.

  In the flow path forming substrate 12, a plurality of pressure generating chambers 11 are partitioned by a partition wall and arranged in parallel in the width direction on the surface layer portion on one side. For example, in this embodiment, a plurality of pressure generating chambers 11 are arranged in parallel on the flow path forming substrate 12. A reservoir 22 to which ink is supplied via an ink introduction port 21 communicating with ink supply means (not shown) outside the case head 20 is disposed outside the row of the pressure generating chambers 11. It is provided penetrating in the thickness direction. The reservoir 22 and each pressure generation chamber 11 communicate with each other via an ink supply port 23, and ink is supplied to each pressure generation chamber 11 from an ink supply unit via an ink introduction port 21 and the reservoir 22. . The ink supply port 23 is formed with a narrower width than the pressure generation chamber 11, and plays a role of maintaining a constant flow path resistance of ink flowing from the reservoir 22 into the pressure generation chamber 11. Further, a nozzle communication hole 24 that penetrates the flow path forming substrate 12 is formed on the end side of the pressure generating chamber 11 opposite to the reservoir 22.

  Thus, in this embodiment, each pressure generating chamber 11 is filled with ink by flowing ink from the reservoir 22 through the ink supply port 23 toward the surface of the flow path forming substrate 12. That is, the flow path forming substrate 12 is provided with the pressure generating chamber 11, the reservoir 22, the ink supply port 23, and the nozzle communication hole 24. Such a flow path forming substrate 12 is made of a silicon single crystal substrate, and the pressure generating chamber 11 and the like provided on the flow path forming substrate 12 are formed by etching the flow path forming substrate 12.

  A nozzle plate 14 having nozzle openings 13 is bonded to one surface side of the flow path forming substrate 12 via an adhesive 50, and each nozzle opening 13 is connected to a nozzle communication hole provided in the flow path forming substrate 12. Each pressure generating chamber 11 is communicated with each other via 24. On the other hand, the diaphragm 15 is bonded to the other surface side of the flow path forming substrate 12, that is, the opening surface side of the pressure generating chamber 11. Each pressure generating chamber 11 is sealed by the vibration plate 15. Here, the vibration plate 15 is formed of a composite plate of an elastic film 25 made of an elastic member such as a resin film and a support plate 26 made of, for example, a metal material that supports the elastic film 25 and is elastic. The film 25 side is bonded to the flow path forming substrate 12. In addition, an island portion 27 with which the tip end portion of the piezoelectric element 17 abuts is provided in a region of the vibration plate 15 facing each pressure generation chamber 11. The front end surface of the piezoelectric element 17 is bonded to the island portion 27 with an adhesive 28. In addition, a compliance portion 29 that is substantially composed only of the elastic film 25 is provided in the region of the vibration plate 15 facing the reservoir 22 by removing the support plate 26 by etching. The compliance portion 29 absorbs the pressure change by the deformation of the elastic film 25 of the compliance portion 29 when the pressure change in the reservoir 22 occurs, and always keeps the pressure in the reservoir 22 constant. Fulfill. Further, the diaphragm 15 is provided with an opening 30 so that the ink introduction port 21 and the reservoir 22 communicate with each other. The diaphragm 15 is bonded to the flow path forming substrate 12 via an adhesive 51.

  The piezoelectric element 17 is integrally formed in one piezoelectric element unit 18. That is, a piezoelectric element forming member 34 in which the piezoelectric material 31 and the electrode forming materials 32 and 33 are vertically sandwiched and laminated is formed to correspond to each pressure generating chamber 11. Each piezoelectric element 17 is formed by cutting into comb teeth. An inactive region that does not contribute to the vibration of the piezoelectric element 17 (piezoelectric element forming member 34), that is, the base end side of the piezoelectric element 17 is fixed to the fixed substrate 35. In this embodiment, the piezoelectric element unit 18 is constituted by the piezoelectric element 17 (piezoelectric element forming member 34) and the fixed substrate 35. In the vicinity of the base end portion of the piezoelectric element 17, a circuit board 37 having a wiring 36 for supplying a signal for driving each piezoelectric element 17 is connected to the surface opposite to the fixed board 35.

  Such a piezoelectric element unit 18 is fixed in a state where the distal end portion of the piezoelectric element 17 is in contact with the island portion 27 of the diaphragm 15 as described above. For example, in this embodiment, the case head 20 is fixed on the diaphragm 15 as described above, and the piezoelectric element unit 18 is accommodated in the accommodating portion 19 of the case head 20 and the piezoelectric element 17 is fixed. The fixed substrate 35 thus fixed is fixed to the case head 20 on the side opposite to the piezoelectric element 17. Specifically, a stepped portion 38 is provided in the accommodating portion 19 of the case head 20, and the fixed substrate 35 is bonded to the stepped portion 38 of the case head 20 with an adhesive 39.

  Further, a wiring board 41 provided with a plurality of conductive pads 40 to which the respective wirings 36 of the circuit board 37 are connected is fixed on the case head 20, and the housing portion 19 of the case head 20 is connected to the wiring board 41. 41 is substantially blocked. The wiring board 41 is formed with a slit-like opening 42 in a region facing the housing part 19 of the case head 20, and the circuit board 37 is drawn out of the housing part 19 from the opening 42 of the wiring board 41. It is.

  Moreover, the circuit board 37 which comprises the piezoelectric element unit 18 consists of chip-on-film (COF) in which the drive IC (not shown) for driving the piezoelectric element 17 was mounted in this embodiment, for example. Each wiring 36 of the circuit board 37 is connected to the electrode forming materials 32 and 33 constituting the piezoelectric element 17 by, for example, solder, anisotropic conductive material, or the like on the base end side. On the other hand, each wiring 36 is joined to each conductive pad 40 of the wiring board 41 on the tip side. Specifically, each wiring 36 is connected to the wiring board 41 in a state in which the tip of the circuit board 37 drawn out of the housing part 19 from the opening 42 of the wiring board 41 is bent along the surface of the wiring board 41. The conductive pads 40 are joined to each other.

  FIG. 2 is an explanatory view showing the planar shapes of various reservoirs according to this embodiment. Here, four types of FIG. 2A to FIG. 2D are shown, but the present invention is not limited to these. However, each of the reservoirs 22, 72, 82, 92 in this embodiment has a plurality (2 to 3 in the figure) of ink inlets (21a, 21b), (71a-71c), (81a-81c), (91a, 91b). ) Is a common first feature. At the same time, the side opposite to the pressure generation chamber 11 (see FIG. 1) in the merged region of the inks supplied from the ink introduction ports (21a, 21b), (71a to 71c), (81a to 81c), and (91a, 91b). Project the wall (upper side in the figure) so that the width in the direction (vertical direction in the figure) perpendicular to the longitudinal direction (horizontal direction in the figure) is smaller than the width of other parts. A common second characteristic is that the aperture portions 22a, (72a, 72b), (82a, 82b), and 92a are formed. That is, from the viewpoint of suppressing ink pressure loss due to the lengthening of the reservoir 22, first, the number of ink inlets (21a, 21b), (71a-71c), (81a-81c), (91a, 91b) In each case, throttle portions 22a, (72a, 72b), (82a, 82b), and 92a are formed in the merging area from the viewpoint of removing ink stagnation in the reservoir 22.

  FIG. 2A shows a case where the reservoir 22 communicates with the two ink inlets 21a and 21b at both ends in the longitudinal direction. The streamline in this case is indicated by an arrow in the figure, and the constricted portion 22a is formed in the merge region where the tip of this arrow hits. Thereby, it is possible to prevent ink stagnation at the merged portion. As a result, the bubbles staying in the stagnation portion can be effectively excluded and the bubble discharge performance can be improved. Further, the streamlines in this case are closer to being parallel to the axis (the vertical direction in the figure) of the pressure generating chamber 11 formed on the lower side in the figure. Therefore, the bubbles can be discharged well by this.

  FIG. 2B shows a case where the reservoir 72 communicates with the two ink introduction ports 71a and 71b at both ends in the longitudinal direction and also communicates with one ink introduction port 71c at the center. That is, although it is a case where it communicates with the three ink introduction ports 71a to 71c, the narrowed portions 72a and 72b are formed in the merge region where the ink introduced from each of the ink introduction ports 71a to 71c merges. In FIG. 2C, the reservoir 82 is divided into three blocks, and the central portion of each block is communicated with the ink inlets 81a, 81b, 81c. In this case, in order to suppress a decrease in the flow velocity at the left end portion to the right end portion of the blocks at both ends, not only the constricting portions 82a and 82b are provided in the confluence region where the inks merge, but also the both end portions of the reservoir 82 are constricted. Relative narrow portions 82c and 82d are formed. Thus, the bubble discharge function of the narrowed portions 82a and 82b and the narrow portions 82c and 82d can be combined to discharge the bubbles well.

  FIG. 2D shows a case where the reservoir 92 communicates with the two ink inlets 91a and 91b at both ends in the longitudinal direction. In this respect, it is the same as that shown in FIG. 2A, but in the case shown in FIG. 2D, the shape of the reservoir 92 itself is further directed from the respective ink inlets 91a and 91b toward the merge region. The width (the dimension in the vertical direction in the drawing) is gradually reduced along the longitudinal direction. Therefore, in this case, the ink flow can be made smooth by the change in the width of the reservoir 92 itself. However, since the flow path resistance increases, it is necessary to adjust the rate of change in width in consideration of the pressure loss due to the flow path resistance.

  2 (a) to 2 (d), the throttle portions 22a and the like are each shaped so that the width gradually decreases from both sides along the longitudinal direction of the reservoir 22 and the like toward the central portion in a predetermined merge region. In addition, the shape is such that the width gradually decreases in a curved manner, but is not limited thereto. The width of the aperture 22 or the like may be a shape that gradually decreases linearly. However, in the case where the width of the narrowed portion 22 and the like is gradually reduced along the ink flow line, the ink can flow most smoothly, and the bubble discharge performance is the best.

  Incidentally, when the long reservoir connected to the plurality of ink inlets does not have the throttle portion 22a or the like as shown in FIG. 2, as shown in FIG. 3 (a) and FIG. 3 (b). Problems occur. That is, the stagnation region 105 of the flow as shown in FIG. 3B is formed in the merging region of the ink supplied from the ink introduction ports 101a and 101b in the reservoir 102, and this causes the phenomenon as shown in FIG. As shown in FIG. 3, the bubbles 104 stay in the stagnation region 105 of FIG. 3B and are not discharged, thereby deteriorating the printing performance.

  According to the present embodiment as described above, ink droplets can be ejected by changing the volume of each pressure generating chamber 11 by deformation of the piezoelectric element 17 and the diaphragm 15. Specifically, when ink is supplied from an ink cartridge (not shown) to the reservoir 22 via the plurality of ink introduction ports 21, the ink is distributed from the ink supply port 23 to each pressure generating chamber 11. Actually, the piezoelectric element 17 is contracted by applying a voltage to the piezoelectric element 17. As a result, the diaphragm 15 is deformed together with the piezoelectric element 17 to expand the volume of the pressure generating chamber 11, and ink is drawn into the pressure generating chamber 11. After the ink is filled up to the nozzle opening 13, the voltage applied to the electrode forming materials 32 and 33 of the piezoelectric element 17 is released according to a recording signal supplied via the wiring board. As a result, the piezoelectric element 17 is expanded to return to the original state, and the diaphragm 15 is also displaced to return to the original state. As a result, the volume of the pressure generation chamber 11 contracts, the pressure in the pressure generation chamber 11 increases, and ink droplets are ejected from the nozzle openings 13.

  When the ink is ejected, the ink in the reservoir 22 is guided to the constricted region restricting portion 22a (see FIG. 2A) as described above and flows into the pressure generating chamber 11 satisfactorily. As a result, it is possible to prevent ink stagnation in the merging region and to obtain good bubble discharge properties.

(Second Embodiment)
FIG. 4 is a cross-sectional view of an ink jet recording head which is an example of a liquid jet head according to the second embodiment of the present invention. As shown in the figure, the ink jet recording head 110 according to this embodiment includes an actuator unit 120 and a flow path unit 130 to which the actuator unit 120 is fixed.

  The actuator unit 120 is an actuator device including the piezoelectric element 140, and includes a flow path forming substrate 122 in which the pressure generation chamber 121 is formed, a vibration plate 123 provided on one surface side of the flow path forming substrate 122, And a pressure generation chamber bottom plate 124 provided on the other surface side of the path forming substrate 122.

The flow path forming substrate 122 is made of, for example, a ceramic plate such as alumina (Al ₂ O ₃ ) or zirconia (ZrO ₂ ) having a thickness of about 150 μm. In this embodiment, the plurality of pressure generating chambers 121 are arranged in the width direction. Are arranged side by side. A vibration plate 123 made of, for example, a stainless steel (SUS) thin plate having a thickness of 10 to 12 μm is fixed to one surface of the flow path forming substrate 122, and one surface of the pressure generating chamber 121 is formed by the vibration plate 123. It is sealed.

  The pressure generation chamber bottom plate 124 is fixed to the other surface side of the flow path forming substrate 122 to seal the other surface of the pressure generation chamber 121, and is provided near one end in the longitudinal direction of the pressure generation chamber 121. A supply communication hole 125 that communicates the generation chamber 121 with a reservoir, which will be described later, and a nozzle communication hole 126 that is provided near the other end in the longitudinal direction of the pressure generation chamber 121 and communicates with a nozzle opening 134 that will be described later.

  The piezoelectric element 140 is provided in each of the regions facing the pressure generation chambers 121 on the vibration plate 123.

  Here, each piezoelectric element 140 is provided on the lower electrode film 141 provided on the vibration plate 123, the piezoelectric layer 142 provided independently for each pressure generation chamber 121, and the piezoelectric layer 142. The upper electrode film 143 is formed. The piezoelectric layer 142 is formed by attaching or printing a green sheet made of a piezoelectric material. The lower electrode film 141 is provided across the piezoelectric layers 142 arranged side by side, serves as a common electrode for each piezoelectric element 140, and functions as a part of the diaphragm. Of course, the lower electrode film 141 may be provided for each piezoelectric layer 142.

  The flow path forming substrate 122, the vibration plate 123, and the pressure generation chamber bottom plate 124, which are each layer of the actuator unit 120, are formed of a clay-like ceramic material, a so-called green sheet, to a predetermined thickness, for example, a pressure generation chamber. After drilling 121 and the like, they are laminated and fired to integrate them without requiring an adhesive. Thereafter, the piezoelectric element 140 is formed on the diaphragm 123.

  On the other hand, the flow path unit 130 is a reservoir forming substrate on which a liquid supply port forming substrate 131 joined to the pressure generating chamber bottom plate 124 of the actuator unit 120 and a reservoir 132 serving as a common ink chamber of the plurality of pressure generating chambers 121 are formed. 133, a compliance substrate 150 provided on the opposite side of the reservoir forming substrate 133 from the liquid supply port forming substrate 131, and a nozzle plate 135 in which the nozzle openings 134 are formed.

  The liquid supply port forming substrate 131 is made of a stainless steel (SUS) thin plate having a thickness of 60 μm, and includes a nozzle communication hole 136 that connects the nozzle opening 134 and the pressure generation chamber 121, and the reservoir 132 together with the supply communication hole 125 described above. An ink supply port 137 that connects to the pressure generating chamber 121 is formed, and an ink introduction port 138 that communicates with each reservoir 132 and supplies ink from an external ink tank is provided. Here, the ink supply ports 137 are provided in the same number as the pressure generation chambers 121 at the same arrangement pitch corresponding to the pressure generation chambers 121. A plurality of ink inlets 138 are provided in accordance with the longitudinal dimension of the reservoir 132. Accordingly, the ink flowing into the reservoir 132 from a plurality of locations joins in an intermediate region between the adjacent ink inlets 138. That is, in the reservoir 132, an ink merging region is formed in an intermediate region between the adjacent ink introduction ports 138.

  The reservoir forming substrate 133 is supplied with ink from an external ink tank (not shown) on a plate material having corrosion resistance such as 150 μm stainless steel, which is suitable for forming an ink flow path. A reservoir 132 for supplying ink, and a nozzle communication hole 139 for communicating the pressure generating chamber 121 and the nozzle opening 134.

  The reservoir 132 is provided across the plurality of pressure generation chambers 121, that is, across one direction that is the direction in which the pressure generation chambers 121 are arranged side by side. Furthermore, the reservoir 132 is configured such that the width between the reservoir inner walls facing each other across the ink supply port 137 is smaller than the width in other regions in the ink merging region as described above. In this embodiment, the narrowed portions 132a and 132b are formed on the inner walls of the reservoir 132 facing each other in the ink merging region to reduce the width of the reservoir 132 in the ink merging region. This will be described in detail later with the addition of FIG.

  The compliance substrate 150 is bonded to the surface of the reservoir forming substrate 133 opposite to the liquid supply port forming substrate 131 to seal the bottom surface of the reservoir 132. Here, the area of the compliance substrate 150 that faces the reservoir 132 is formed with a smaller thickness than the other areas, thereby forming a compliance portion 151 that is deformed by the pressure change of the reservoir 132. As a material of the compliance substrate 150, for example, a metal such as stainless steel or a ceramic can be used. Of course, the compliance substrate 150 is not particularly limited to this. For example, the compliance substrate 150 may be configured by a film-like elastic film constituting the compliance portion 151 and a support substrate provided with a part in the thickness direction penetrating therethrough. May be.

  Further, the compliance substrate 150 is provided with a nozzle communication hole 152 that penetrates in the thickness direction and communicates the nozzle communication hole 139 provided in the reservoir forming substrate 133 and the nozzle opening 134. That is, the ink from the pressure generation chamber 121 is ejected from the nozzle opening 134 through the nozzle communication holes 136, 139, and 152 provided in the liquid supply port forming substrate 131, the reservoir forming substrate 133, and the compliance substrate 150.

  The nozzle plate 135 is formed, for example, by forming nozzle openings 134 in a thin plate made of stainless steel at the same arrangement pitch as the pressure generating chambers 121.

  Such a flow path unit 130 is formed by fixing the liquid supply port forming substrate 131, the reservoir forming substrate 133, the compliance substrate 150, and the nozzle plate 135 with an adhesive, a heat welding film, or the like. And such a flow path unit 130 and the actuator unit 120 are joined and fixed via an adhesive or a heat welding film.

  FIG. 5 is an explanatory view showing the planar shapes of various reservoirs according to this embodiment. The reservoir 132, in particular its throttle parts 132a and 132b, etc. will be described in detail with the addition of this figure.

  FIG. 5A shows a case where the reservoir 132 communicates with the two ink introduction ports 138a and 138b at both ends in the longitudinal direction, and is shown in FIG. 2A in the first embodiment. Corresponds to the case. In the case of the first embodiment shown in FIG. 1 and FIG. 2A, the reservoir 22 supplies ink to the pressure generating chamber 11 from the direction parallel to the surface direction of the flow path forming substrate 12 through the ink supply port 23. Since the ink supply port 23 is configured to supply, only the inner wall surface of the reservoir 22 with which the ink supply port 23 opposes is projected.

  On the other hand, in this embodiment, since the ink supply port 137 is formed between the opposing inner walls 132c and 132d of the reservoir 132, only the throttle portion 132a is provided on the inner wall 132c side on the ink introduction ports 138a and 138b side. Is not enough. Stagnation occurs in the merging region on the inner wall 132d side of the ink that has flowed into the reservoir 132 through the ink introduction ports 138a and 138b, and bubbles resulting from this stagnation grow, and the pressure generation chamber 121 passes through the ink supply port 137. This is because there is a possibility of flowing into the inside. In particular, when the distance d from the inner wall 132d to the ink supply port 137 is larger than the size of a small-sized bubble that is likely to disappear naturally or a bubble that is desired to be discharged, the grown bubble is pressurized through the ink supply port 137. The possibility of flowing into the generation chamber 121 is increased.

  Therefore, in this embodiment, the throttle part 132b is also provided on the inner wall 132d side. That is, the narrowed portions 132a and 132b are formed on the inner walls 132c and 132d of the reservoir 132 facing each other in the ink merging region to reduce the width of the reservoir 132 in the ink merging region.

  FIG. 5A shows streamlines in this case by arrows. The constricted portions 132a and 132b are formed in the merging region where the tips of the arrows meet. Thereby, it is possible to prevent ink stagnation at the merged portion. As a result, the bubbles staying in the stagnation portion can be effectively excluded and the bubble discharge performance can be improved.

  FIG. 5B shows a case where the reservoir 172 communicates with the two ink introduction ports 171a and 171b at both ends in the longitudinal direction, and communicates with one ink introduction port 171c at the center. This corresponds to the case shown in FIG. 2B in the first embodiment. That is, in the case of communicating with the three ink introduction ports 171a to 171c, not only the constricted portions 172a and 172b are formed in the merge region where the inks introduced from the ink introduction ports 171a to 171c merge. The diaphragm portions 172c and 172d are formed at positions opposite to these.

  In FIG. 5C, the reservoir 182 is divided into three blocks, and the central portion of each block is communicated with the ink inlets 181a, 181b, and 181c. This corresponds to the case shown in FIG. 2C in the first embodiment. In this case, in order to suppress a decrease in the flow velocity at the left end portion to the right end portion of the blocks at both ends, not only the constricting portions 182a and 182b are provided in the confluence region where the inks merge, but also the both end portions of the reservoir 182 are constricted. Relative narrow portions 182c and 182d are formed. At the same time, narrowed portions 182e and 182f are provided at positions facing the narrowed portions 182a and 182b, and narrow portions 182g and 182h are provided at positions facing the narrowed portions 182c and 182d, respectively.

  Thus, the bubble discharge function of the narrowed portions 182a, 182b, 182e, 182f and the narrow portions 182c, 182d, 182g, 182h can be combined to discharge the bubbles well.

  FIG. 5D shows a case where the reservoir 192 communicates with the two ink inlets 191a and 191b at both ends in the longitudinal direction. This point is the same as the case shown in FIG. 5A, but in the case shown in FIG. 5D, the shape of the reservoir 192 itself is further directed from the respective ink inlets 191a and 191b toward the merge region. The inner wall 192c is formed so that the width (dimension in the vertical direction in the drawing) gradually decreases along the longitudinal direction, and the inner wall 192d opposite to the inner wall 192c is also formed in a symmetrical shape. Thus, the narrowed portions 192a and 192b are formed in the ink merging region.

  Therefore, in this case, the flow of ink can be made smooth by the change in the width of the reservoir 192 itself. However, since the flow path resistance increases, it is necessary to adjust the rate of change in width in consideration of the pressure loss due to the flow path resistance.

  5 (a) to 5 (d), the narrowed portion 132a or the like has a shape in which the width gradually decreases from both sides along the longitudinal direction of the reservoir 132 or the like toward the central portion in a predetermined merging region. In addition, the shape is such that the width gradually decreases in a curved manner, but is not limited thereto. The width of the aperture 132a or the like may be a shape that gradually decreases linearly. However, in the case where the width of the narrowed portion 132a and the like is gradually reduced along the ink flow line, the ink can flow most smoothly, and the bubble discharge performance is the best.

  According to this embodiment as described above, ink is taken into the reservoir 132 from the ink cartridge (reserving means) via the plurality of ink inlets 138, and the ink flow path from the reservoir 132 to the nozzle opening 134 is filled with ink. After that, according to a recording signal from a drive circuit (not shown), a voltage is applied to each piezoelectric element 140 corresponding to each pressure generating chamber 121 to bend and deform the diaphragm 123 together with the piezoelectric element 140, thereby each pressure generating chamber 121. The internal pressure increases and ink droplets are ejected from the nozzle openings 134.

  When the ink is ejected, the ink in the reservoir 132 is guided to the constricted areas 132a and 132b in the merge area as described above and flows into the pressure generating chamber 121 satisfactorily. As a result, it is possible to prevent ink stagnation in the merging region and to obtain good bubble discharge properties.

(Other embodiments)
In the above embodiment, an inkjet recording head or the like having a longitudinal vibration type piezoelectric element in which piezoelectric materials and electrode forming materials are alternately stacked and expanded and contracted in the axial direction has been described. The type of ink jet recording head is not limited. For example, an ink jet recording head having a thick film type piezoelectric element, for example, an ink jet recording head having a thin film type piezoelectric element having a piezoelectric material formed by a sol-gel method, a MOD method, a sputtering method, etc. Ink-jet recording head with so-called electrostatic actuator that arranges electrodes with a predetermined gap and controls the vibration of the diaphragm with electrostatic force. The same effect can be obtained even with an ink jet recording head that ejects liquid droplets from the nozzle openings using bubbles.

  The ink jet recording head according to the above embodiment constitutes a part of a recording head unit having an ink introduction port communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 6 is a schematic view showing an example of the ink jet recording apparatus. As shown in the figure, recording head units 1A and 1B having ink jet recording heads are provided with cartridges 2A and 2B constituting ink supply means in a detachable manner, and a carriage 3 on which the recording head units 1A and 1B are mounted. Is provided on a carriage shaft 5 attached to the apparatus body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

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

  In the above-described embodiment, an ink jet recording head has been described as an example of a liquid ejecting head. However, the present invention is widely intended for all liquid ejecting heads and ejects liquids other than ink. Of course, the present invention can also be applied to an inspection method for a liquid jet head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

  10,110 Inkjet recording head, 11,121 pressure generating chamber, 12,122 flow path forming substrate, 13,134 nozzle opening, 14,135 nozzle plate, 15,123 diaphragm, 16,130 flow path unit, 17, 140 piezoelectric elements, 18 piezoelectric element units, 19 housing parts, 20 case heads, 21, 138 ink inlets, 22, 132 reservoirs, 22a, 132a throttle parts

An aspect of the present invention that solves the above-described problems includes a pressure generation chamber arranged in parallel to a substrate so as to discharge liquid through a nozzle opening due to pressure fluctuation, and pressure generation that causes pressure fluctuation in the liquid in the pressure generation chamber. Means and a reservoir that is supplied with the liquid via a plurality of inlets and supplies the liquid to each of the pressure generating chambers via a supply port, the plurality of inlets being a first inlet. An inner wall of the reservoir, and a convex portion between the first inlet and the second inlet, the inner wall of the reservoir being deformed by a pressure change in the reservoir. The liquid ejecting head is characterized in that a front end of the throttling portion does not overlap the compliance portion .
The compliance portion may be provided on a bottom surface of the reservoir, and the throttle portion may be provided on a side surface of the reservoir.
The compliance unit may be provided on a compliance substrate fixed to the substrate on which the reservoir is provided.
In another aspect of the present invention, a pressure generating chamber arranged in parallel to the substrate so as to discharge liquid through a nozzle opening due to pressure fluctuation, and pressure generating means for causing pressure fluctuation in the liquid in the pressure generating chamber, A reservoir provided on the substrate to supply the liquid to the pressure generation chamber and to form a common liquid chamber provided in the direction in which the pressure generation chambers are juxtaposed, and the reservoir includes a plurality of reservoirs. The liquid is supplied from the liquid introduction port, and a cross-sectional area of the reservoir is smaller than a cross-sectional area of the reservoir in a predetermined region other than the confluence region in the confluence region of the liquid supplied from the liquid introduction ports. The liquid ejecting head is configured as described above.

Claims (9)

A pressure generating chamber arranged in parallel to the substrate so as to discharge liquid through the nozzle opening due to pressure fluctuation;
Pressure generating means for causing a pressure fluctuation in the liquid in the pressure generating chamber;
A reservoir provided on the substrate to supply the liquid to the pressure generating chamber and to form a common liquid chamber provided across the direction in which the pressure generating chambers are arranged;
The reservoir is supplied with the liquid from a plurality of liquid inlets, and the cross-sectional area of the reservoir in a merging region of the liquid supplied from the liquid inlets is a disconnection of the reservoir in a predetermined region other than the merging region. A liquid ejecting head characterized by being configured to be smaller than an area. The liquid ejecting head according to claim 1,
The reservoir is configured to supply the liquid to the pressure generation chamber via a liquid supply port in a direction along the surface of the substrate, and an inner wall of the reservoir facing the liquid supply port in the merging region includes A liquid ejecting head having a convex shape toward a liquid supply port. The liquid ejecting head according to claim 1,
The reservoir is configured to supply the liquid to the pressure generation chamber via a liquid supply port in the thickness direction of the substrate, and extends in a direction in which the pressure generation chambers are arranged across the liquid supply port. Each of the reservoir inner walls is configured to be convex toward the opposite reservoir inner walls in the merging region. The liquid ejecting head according to claim 3,
The reservoir inner walls extending in the direction in which the pressure generating chambers are juxtaposed across the liquid supply port in the predetermined region are all separated from the liquid supply port by a distance larger than the diameter of the bubble that can naturally disappear. A liquid ejecting head. In the liquid ejecting head according to any one of claims 1 to 4,
A liquid ejecting head, wherein a constricted portion is formed in the merging region. The liquid ejecting head according to claim 5,
The narrowed portion has a shape such that the width gradually decreases from the liquid inlet side in the juxtaposed direction of the pressure generating chambers toward an intermediate portion of the adjacent liquid inlet. . In the liquid ejecting head according to claim 5 or 6,
The liquid ejecting head according to claim 1, wherein the width of the narrowed portion is formed so as to gradually decrease along a flow line of the liquid. The liquid ejecting head according to any one of claims 5 to 7,
The liquid ejecting head according to claim 1, wherein a plurality of the throttle portions are provided in the reservoir.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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