Patent Publication Number: US-11040534-B2

Title: Liquid ejecting head and liquid ejecting apparatus

Description:
The present application is based on, and claims priority from JP Application Serial Number 2018-244286, filed Dec. 27, 2018, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a liquid ejecting head and a liquid ejecting apparatus which eject a liquid from a nozzle, particularly, to an ink jet type recording head and an ink jet type recording apparatus which discharge an ink as a liquid. 
     2. Related Art 
     As a liquid ejecting head that ejects a liquid, there is known an ink jet type recording head that performs printing by discharging an ink as a liquid onto a printed medium. 
     The ink jet type recording head includes an individual flow path having a pressure chamber that communicates with a nozzle, a common liquid chamber that communicates in common with a plurality of the individual flow paths, and an energy generating element such as a piezoelectric actuator that induces a change in the pressure of the ink in the pressure chamber. If the energy generating element induces a change in the pressure of the ink in the pressure chamber, ink droplets are discharged from the nozzle. 
     In the ink jet type recording head described above, if air bubbles stay in the pressure chamber, the air bubbles absorb the pressure change induced by the energy generating element, and thus it is not possible to normally discharge the ink droplets from the nozzle. 
     For this reason, there is proposed an ink jet type recording head having a configuration where a first common liquid chamber and a second common liquid chamber are provided as common liquid chambers which are in common with individual flow paths, and an ink flows, namely, so-called circulation is performed from the first common liquid chamber to the second common liquid chamber through the individual flow paths (for example, refer to JP-A-2012-143948). 
     However, there occurs a problem like the occurrence of a discharge defect such as the ink being thickened in the vicinity of the nozzle, the nozzle being clogged by air bubbles that infiltrate from the nozzle, or a deviation in the flying direction of ink droplets. 
     The above-mentioned problem exists not only in the ink jet type recording head, similarly but also in liquid ejecting heads that eject liquids other than an ink. 
     SUMMARY 
     An advantage of some aspects of the present disclosure is to provide a liquid ejecting head and a liquid ejecting apparatus which are capable of preventing a discharge defect by removing a thickened liquid in the vicinity of a nozzle and air bubbles. 
     According to an aspect of the present disclosure, there is provided a liquid ejecting head including a flow path substrate which includes a nozzle plate and in which a flow path is formed; and an energy generating element inducing a change in a pressure of a liquid in the flow path. The flow path includes a first common liquid chamber, a second common liquid chamber, and a plurality of individual flow paths which communicate with the first common liquid chamber and the second common liquid chamber and through which the liquid flows from the first common liquid chamber toward the second common liquid chamber. The individual flow path includes a nozzle communicating with an outside, a first flow path, in the middle of which the nozzle is disposed and which extends in a first direction that is an in-plane direction of a nozzle surface of the nozzle plate in which the nozzle opens, a second flow path coupled to the first flow path and extending in a second direction other than the first direction, a third flow path coupled to the second flow path and extending in a third direction other than the second direction, and a pressure chamber which is disposed in the third flow path and in which a pressure change is induced by the energy generating element. The first flow path includes a portion having a first cross-sectional area on a side that is closer to the second flow path than the nozzle, and a portion having a second cross-sectional area, which is smaller than the first cross-sectional area, on a side that is opposite to the second flow path across the nozzle. 
     In addition, according to another aspect, there is provided a liquid ejecting apparatus including the liquid ejecting head described in the aspect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a recording head according to Embodiment 1 of the present disclosure. 
         FIG. 2  is a cross-sectional view of the recording head according to Embodiment 1 of the present disclosure. 
         FIG. 3  is a cross-sectional view of the recording head according to Embodiment 1 of the present disclosure. 
         FIG. 4  is a cross-sectional view of the recording head according to Embodiment 1 of the present disclosure. 
         FIG. 5  is a cross-sectional view of the recording head according to Embodiment 1 of the present disclosure. 
         FIG. 6  is a cross-sectional view of a recording head according to Embodiment 2 of the present disclosure. 
         FIG. 7  is a cross-sectional view of the recording head according to Embodiment 2 of the present disclosure. 
         FIG. 8  is a cross-sectional view of the recording head according to Embodiment 2 of the present disclosure. 
         FIG. 9  is a cross-sectional view illustrating a comparative example of the recording head according to Embodiment 2 of the present disclosure. 
         FIG. 10  is a plan view of a recording head according to Embodiment 3 of the present disclosure. 
         FIG. 11  is a cross-sectional view of the recording head according to Embodiment 3 of the present disclosure. 
         FIG. 12  is a cross-sectional view of the recording head according to Embodiment 3 of the present disclosure. 
         FIG. 13  is a diagram schematically illustrating flow paths according to Embodiment 3 of the present disclosure. 
         FIG. 14  is a cross-sectional view illustrating a recording head according to an embodiment of the present disclosure. 
         FIG. 15  is a cross-sectional view illustrating the recording head according to the embodiment of the present disclosure. 
         FIG. 16  is a cross-sectional view illustrating a recording head according to an embodiment of the present disclosure. 
         FIG. 17  is a cross-sectional view illustrating the recording head according to the embodiment of the present disclosure. 
         FIG. 18  is a cross-sectional view illustrating a recording head according to an embodiment of the present disclosure. 
         FIG. 19  is a cross-sectional view illustrating the recording head according to the embodiment of the present disclosure. 
         FIG. 20  is a diagram schematically illustrating flow paths according to the embodiment of the present disclosure. 
         FIG. 21  is a view illustrating a schematic configuration of a recording apparatus according to one embodiment of the present disclosure. 
         FIG. 22  is a block diagram describing an ink system according to one embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, the present disclosure will be described in detail based on embodiments. However, the following description illustrates one aspect of the present disclosure, and can be arbitrarily changed within the scope of the present disclosure. In each drawing, the same reference signs are assigned to the same members, and the description will be appropriately omitted. In addition, in each drawing, X, Y, and Z denote three space axes that orthogonally intersect each other. In the specification, directions along the axes are an X direction, a Y direction, and a Z direction, respectively. In each drawing, a direction pointed by an arrow is described as a positive (+) direction, and a direction opposite to the arrow is described as a negative (−) direction. In addition, the Z direction indicates a vertical direction, a +Z direction indicates a vertical downward direction, and a −Z direction indicates a vertical upward direction. 
     Embodiment 1 
     An ink jet type recording head which is one example of a liquid ejecting head of an embodiment will be described with reference to  FIGS. 1 to 5 . Incidentally,  FIG. 1  is a plan view of the ink jet type recording head which is one example of a liquid ejecting head according to Embodiment 1 of the present disclosure, which is seen from a nozzle surface side.  FIG. 2  is a cross-sectional view taken along a line II-II in  FIG. 1 .  FIG. 3  is an enlarged view of a main part in  FIG. 2 . 
     An ink jet type recording head  1  (hereinafter, referred to simply also as a recording head  1 ) which is one example of the liquid ejecting head of the embodiment includes, as illustrated, a plurality of members as a flow path substrate such as a flow path formation substrate  10 , a communication plate  15 , a nozzle plate  20 , a protection substrate  30 , a case member  40 , and a compliance substrate  49 . 
     The flow path formation substrate  10  is made of a single crystal silicon substrate, and a vibrating plate  50  is formed on one surface thereof. The vibrating plate  50  may be a single layer or a lamination layer selected from a silicon dioxide layer or a zirconium oxide layer. 
     The flow path formation substrate  10  is provided with a plurality of pressure chambers  12  which form individual flow paths  200  and are partitioned off by a plurality of partition walls. The plurality of pressure chambers  12  are arranged side by side at a predetermined pitch along the X direction where a plurality of nozzles  21  discharging an ink are arranged side by side. In addition, in the embodiment, one row of the pressure chambers  12  are arranged side by side in the X direction. In addition, the flow path formation substrate  10  is disposed such that an in-plane direction includes the X direction and the Y direction. Incidentally, in the embodiment, a portion between the pressure chambers  12  which are arranged side by side in the flow path formation substrate  10  in the X direction is referred to as a partition wall. The partition wall is formed along the Y direction. Namely, the partition wall refers to a portion that overlaps the pressure chamber  12  of the flow path formation substrate  10  in the Y direction. 
     Incidentally, in the embodiment, only the pressure chamber  12  is provided in the flow path formation substrate  10 ; however, but a flow path resistance application portion having a flow path cross-sectional area smaller than that of the pressure chamber  12  may be provided in the flow path formation substrate  10  so as to apply a flow path resistance to the ink to be supplied to the pressure chamber  12 . 
     The vibrating plate  50  is formed on one surface side of the flow path formation substrate  10  described above in the −Z direction. A piezoelectric actuator  300  is formed by laminating a first electrode  60 , a piezoelectric layer  70 , and a second electrode  80  on the vibrating plate  50  by deposition and lithography. In the embodiment, the piezoelectric actuator  300  is an energy generating element that induces a change in the pressure of the ink in the pressure chamber  12 . Herein, the piezoelectric actuator  300  is referred to also as a piezoelectric element, and refers to a portion including the first electrode  60 , the piezoelectric layer  70 , and the second electrode  80 . Generally, either one electrode of the piezoelectric actuator  300  is configured as a common electrode, and the other electrode and the piezoelectric layer  70  are formed for each of the pressure chambers  12  by patterning. In the embodiment, the first electrode  60  is formed as a common electrode of the piezoelectric actuator  300 , and the second electrode  80  is formed as an individual electrode of the piezoelectric actuator  300 , but even though the configuration becomes reversed for the reasons of drive circuits or wirings, there is no problem. Incidentally, in the example described above, the vibrating plate  50  and the first electrode  60  act as a vibrating plate. However, naturally, the present disclosure is not limited to this configuration, for example, the vibrating plate  50  may not be provided, and only the first electrode  60  may act as a vibrating plate. In addition, the piezoelectric actuator  300  may serve substantially as a vibrating plate. 
     In addition, lead electrodes  90  are coupled to the second electrodes  80  of the piezoelectric actuators  300  described above, and a voltage is selectively applied to the piezoelectric actuators  300  via the lead electrodes  90 . 
     In addition, the protection substrate  30  is joined to a surface of the flow path formation substrate  10 , on which the piezoelectric actuator  300  is provided. 
     A piezoelectric actuator holding portion  31  having a space not to obstruct the motion of the piezoelectric actuator  300  is provided in a region of the protection substrate  30 , which faces the piezoelectric actuator  300 . The piezoelectric actuator holding portion  31  may have a space not to obstruct the motion of the piezoelectric actuator  300 , and the space may be sealed or may not be sealed. In addition, the piezoelectric actuator holding portion  31  is formed having a size to integrally cover a row of the plurality of piezoelectric actuators  300  that are arranged side by side in the first direction X. Naturally, the piezoelectric actuator holding portion  31  is not specifically limited to the configuration, and may individually cover the piezoelectric actuator  300 , or may cover each group formed of two or more piezoelectric actuators  300  that are arranged side by side in the first direction X. 
     Preferably, a material, for example, a glass or ceramic material having substantially the same coefficient of thermal expansion as that of the material of the flow path formation substrate  10  is used as the material of the protection substrate  30  described above. In the embodiment, the protection substrate  30  is formed of a single crystal silicon substrate which is the same material as that of the flow path formation substrate  10 . 
     In addition, the protection substrate  30  is provided with a through hole  32  penetrating the protection substrate  30  in the Z direction. The vicinity of an end portion of the lead electrode  90  leading out from each of the piezoelectric actuators  300  extends so as to be exposed in the through hole  32 , and is electrically coupled to a flexible cable  120  in the through hole  32 . The flexible cable  120  is a wiring substrate having flexibility, and in the embodiment, a drive circuit  121  which is a semiconductor element is mounted thereon. Incidentally, the lead electrode  90  may be electrically coupled to the drive circuit  121  without via the flexible cable  120 . In addition, the protection substrate  30  may be provided with a flow path. 
     In addition, the case member  40 , which, together with the protection substrate  30 , defines supply side supply flow paths communicating with the plurality of pressure chambers  12 , is fixed onto the protection substrate  30 . The case member  40  is provided to be joined to a surface side of the protection substrate  30 , which is opposite to the flow path formation substrate  10 , and joined also to the communication plate  15  (to be described later). 
     The case member  40  described above is provided with a first liquid chamber portion  41  forming part of a first common liquid chamber  101 , and a second liquid chamber portion  42  forming part of a second common liquid chamber  102 . The first liquid chamber portion  41  and the second liquid chamber portion  42  are provided on both sides in the Y direction, respectively, where one row of the pressure chambers  12  are interposed therebetween. 
     Each of the first liquid chamber portion  41  and the second liquid chamber portion  42  has a recessed shape that opens in a +Z side surface of the case member  40 , and is continuously provided over the plurality of pressure chambers  12  that are arranged side by side in the X direction. 
     In addition, the case member  40  is provided with an inlet port  43  which communicates with the first liquid chamber portion  41  and through which the ink flows into the first liquid chamber portion  41 , and an outlet port  44  which communicates with the second liquid chamber portion  42  and through which the ink flows out from the second liquid chamber portion  42 . 
     Furthermore, the case member  40  is provided with a coupling port  45  which communicates with the through hole  32  of the protection substrate  30 , and into which the flexible cable  120  is inserted. 
     On the one hand, the communication plate  15 , the nozzle plate  20 , and the compliance substrate  49  are provided on the +Z side that is a surface side of the flow path formation substrate  10 , which is opposite to the protection substrate  30 . 
     The nozzle plate  20  is provided with the plurality of nozzles  21  which communicate with the outside and communicate with the pressure chambers  12 . In the embodiment, as illustrated in  FIG. 1 , one row of a nozzle row  22  is formed by disposing the plurality of nozzles  21  on a straight line along the X direction. 
     The nozzle  21  has a first hole  21   a  and a second hole  21   b  which have different inner diameters. The first hole  21   a  and the second hole  21   b  are disposed side by side in the Z direction which is a thickness direction of the nozzle plate  20 . The inner diameter of the first hole  21   a  is smaller than the inner diameter of the second hole  21   b . The first hole  21   a  of the nozzle  21  is disposed on an outside of the nozzle plate  20 , namely, on the +Z side, and the second hole  21   b  is disposed on a −Z side of the nozzle plate  20 , which is a side close to a first flow path  201  (to be described in detail later). 
     As described above, if the nozzle  21  is provided with the first hole  21   a  having a relatively small inner diameter, it is possible to improve the flow speed of the ink and the discharge speed of ink droplets to be discharged. In addition, if the nozzle  21  is provided with the second hole  21   b  having a relatively large inner diameter, when the ink flows through the individual flow path  200  from the first common liquid chamber  101  toward the second common liquid chamber  102  (to be described in detail later), namely, when so-called circulation is performed, it is possible to reduce a portion that is not influenced by the flow of circulation. Therefore, a speed gradient becomes large, and thus it is possible to easily remove the ink thickened by the nozzle  21 . 
     Incidentally, in the embodiment, the inner diameter of the nozzle  21  is stepwise changed by the first hole  21   a  and the second hole  21   b , but is not limited to the stepwise change. The inner diameter of the nozzle  21  may be continuously changed such that an inner surface of the nozzle  21  is an inclined surface inclined with respect to the Z direction. In addition, the shape of the nozzle  21  in a plan view from the Z direction is not specifically limited, and may be a circular shape, an oval shape, a rectangular shape, a polygonal shape, a dharma shape, or the like. 
     The nozzle plate  20  described above can be formed of a planar member made of metal such as stainless steel (SUS), an organic matter such as polyimide resin, or silicon. In addition, preferably, the thickness of the nozzle plate  20  is from 60 μm to 100 μm. It is possible to improve the handleability of the nozzle plate  20 , and the ease to assemble the recording head  1  by using the nozzle plate  20  having the above-mentioned thickness. 
     In the embodiment, the communication plate  15  has a first communication plate  151  and a second communication plate  152 . The first communication plate  151  and the second communication plate  152  are laminated on top of each other in the Z direction such that the first communication plate  151  is positioned close to the flow path formation substrate  10  and the second communication plate  152  is positioned close to the nozzle plate  20  in the Z direction. 
     The first communication plate  151  and the second communication plate  152  forming the communication plate  15  described above can be manufactured of a metallic material such as stainless steel, a glass material, or a ceramic material, or the like. Incidentally, preferably, a material having substantially the same coefficient of thermal expansion as that of the material of the flow path formation substrate  10  is used as the material of the communication plate  15 . In the embodiment, the communication plate  15  is formed of a single crystal silicon substrate which is the same material as that of the flow path formation substrate  10 . 
     The communication plate  15  is provided with a first communication portion  16  that communicates with the first liquid chamber portion  41  of the case member  40  and forms part of the first common liquid chamber  101 , and a second communication portion  17  and a third communication portion  18  that communicate with the second liquid chamber portion  42  of the case member  40  and form part of the second common liquid chamber  102 . In addition, the communication plate  15  is, as will be described in detail later, provided with a flow path through which the first common liquid chamber  101  communicates with the pressure chamber  12 , a flow path through which the pressure chamber  12  communicates with the nozzle  21 , and a flow path through which the nozzle  21  communicates with the second common liquid chamber  102 . The flow paths provided in the communication plate  15  form part of the individual flow path  200 . 
     The first communication portion  16  is provided at a position to overlap the first liquid chamber portion  41  of the case member  40  in the Z direction, and opens in both of the +Z and −Z side surfaces of the communication plate  15 , namely, is provided to penetrate the communication plate  15  in the Z direction. The first communication portion  16  communicates with the first liquid chamber portion  41  on the −Z side to form the first common liquid chamber  101 . Namely, the first common liquid chamber  101  is formed of the first liquid chamber portion  41  of the case member  40  and the first communication portion  16  of the communication plate  15 . In addition, the first communication portion  16  extends in the Y direction to a position on the +Z side to overlap the pressure chamber  12  in the Z direction. Incidentally, the communication plate  15  may not be provided with the first communication portion  16 , and the first common liquid chamber  101  may be formed of the first liquid chamber portion  41  of the case member  40 . 
     The second communication portion  17  is provided at a position to overlap the second liquid chamber portion  42  of the case member  40  in the Z direction, and is provided to be open in the −Z side surface of the first communication plate  151 . In addition, the second communication portion  17  is provided on the +Z side so as for the width to be widened toward the nozzle  21  in a +Y direction. 
     The third communication portion  18  is provided to penetrate the second communication plate  152  in the Z direction at a position which permits communication with a portion of the second communication portion  17 , the width of which is widened on the +Z side toward the nozzle  21  in the +Y direction. A +Z side opening of the third communication portion  18  is covered with the nozzle plate  20 . 
     The second common liquid chamber  102  is formed of the second communication portion  17  and the third communication portion  18  provided in the communication plate  15  described above, and the second liquid chamber portion  42  provided in the case member  40 . Incidentally, the communication plate  15  may not be provided with the second communication portion  17  and the third communication portion  18 , and the second common liquid chamber  102  may be formed of the second liquid chamber portion  42  of the case member  40 . 
     The compliance substrate  49  having a compliance portion  494  is provided in the +Z side surface of the communication plate  15 , in which the first communication portion  16  opens. The compliance substrate  49  seals an opening of the first common liquid chamber  101 , which is close to a nozzle surface  20   a.    
     In the embodiment, the compliance substrate  49  described above includes a sealing film  491  made of a thin film having flexibility, and a fixation substrate  492  made of a hard material such as metal. Since a region of the fixation substrate  492  which faces the first common liquid chamber  101  becomes an opening portion  493  formed by completely removing the region in a thickness direction, part of a wall surface of the first common liquid chamber  101  becomes the compliance portion  494  which is a flexible portion sealed only with the sealing film  491  having flexibility. As described above, if the compliance portion  494  is provided in part of the wall surface of the first common liquid chamber  101 , the compliance portion  494  is capable of, by being deformed, absorbing a fluctuation in the pressure of the ink in the first common liquid chamber  101 . 
     In addition, in the embodiment, since the first common liquid chamber  101  is provided so as to open on the +Z side on which the nozzle  21  opens, the nozzle plate  20  and the compliance portion  494  are disposed on the +Z side which is the same side with respect to the individual flow path  200  having the pressure chamber  12  and the nozzle  21  in the Z direction which is a normal direction of the nozzle surface  20   a . As described above, if the compliance portion  494  is disposed on the same side as the nozzle  21  with respect to the individual flow path  200 , it is possible to provide the compliance portion  494  in a region where the nozzle  21  is not provided, and it is possible to provide the compliance portion  494  having a relatively wide area. In addition, if the compliance portion  494  and the nozzle  21  are disposed on the same side with respect to the individual flow path  200 , the compliance portion  494  is disposed at a position close to the individual flow path  200 , and thus the compliance portion  494  is capable of effectively absorbing a fluctuation in the pressure of the ink in the individual flow path  200 . 
     In addition, the flow path formation substrate  10 , the communication plate  15 , the nozzle plate  20 , the compliance substrate  49 , and the like which form the flow path substrate are provided with a plurality of the individual flow paths  200  which communicate with the first common liquid chamber  101  and the second common liquid chamber  102  and deliver the ink of the first common liquid chamber  101  to the second common liquid chamber  102 . Herein, the individual flow paths  200  of the embodiment communicate with the first common liquid chamber  101  and the second common liquid chamber  102 , are provided for each of the nozzles  21 , and include the nozzle  21 . As described above, three individual flow paths  200  adjacent to each other in the X direction which is a direction where the nozzles  21  are arranged side by side are provided to communicate with the first common liquid chamber  101  and the second common liquid chamber  102 . Namely, the plurality of individual flow paths  200  provided for each of the nozzles  21  are provided to communicate only with the first common liquid chamber  101  and the second common liquid chamber  102 . The plurality of individual flow paths  200  do not communicate with parts other than the first common liquid chamber  101  and the second common liquid chamber  102 . Namely, in the embodiment, flow paths provided with one nozzle  21  and one pressure chamber  12  are referred to as the individual flow path  200 , and the individual flow paths  200  are provided to communicate only with the first common liquid chamber  101  and the second common liquid chamber  102 . 
     In addition, in the embodiment, flow paths of the individual flow path  200  which are closer to the first common liquid chamber  101  than the nozzle  21  are referred to as upstream flow paths, and flow paths of the individual flow path  200  which are closer to the second common liquid chamber  102  than the nozzle  21  are referred to as downstream flow paths. 
     As illustrated in  FIG. 2 , the individual flow path  200  includes the nozzle  21 ; the pressure chamber  12  forming a third flow path; the first flow path  201 ; a second flow path  202 ; and a supply path  203 . 
     The pressure chamber  12  is, as described above, provided in the flow path formation substrate  10 , and extends in the Y direction which is a third direction. Namely, the pressure chamber  12  is provided such that the supply path  203  is coupled to one end portion of the pressure chamber  12  in the Y direction, the second flow path  202  is coupled to the other end portion thereof in the Y direction, and the ink flows through the pressure chamber  12  in the Y direction. Namely, an extending direction of the pressure chamber  12  is a direction where the ink flows through the pressure chamber  12 . 
     Since the pressure chamber  12  of the embodiment extends, as described above, in the Y direction, the pressure chamber  12  extends in a direction other than the Z direction which is a second direction where the second flow path  202  (to be described in detail later) extends. 
     In addition, the pressure chamber  12  forms the third flow path which is a flow path extending in the direction other than the Z direction. The third flow path of the embodiment is formed only of the pressure chamber  12 . Naturally, the third flow path is not limited to the configuration. As described above, if a flow path resistance application portion having a cross-sectional area smaller than that of the pressure chamber  12  is provided so as to apply a flow path resistance to the end portions of the pressure chamber  12 , the third flow path is formed of the pressure chamber  12  and the flow path resistance application portion. In addition, the pressure chamber  12  of the embodiment extends in the Y direction, but may extend in a direction that is different from the Z direction which is the second direction, or may extend in the X direction. 
     The supply path  203  is a flow path through which the pressure chamber  12  is coupled to the first common liquid chamber  101 , and is provided to penetrate the first communication plate  151  in the Z direction. Namely, one end portion of the supply path  203  on the +Z side communicates with the first common liquid chamber  101 , and the other end portion thereof on the −Z side communicates with the pressure chamber  12 . The supply path  203  described above extends in the Z direction. Herein, the extending direction of the supply path  203  is a direction where the ink flows through the supply path  203 . 
     The first flow path  201  extends in an in-plane direction of the nozzle plate  20 , namely, an in-plane direction of the nozzle surface  20   a . In the embodiment, the first flow path  201  extends in the Y direction between directions including the X direction, which is the in-plane direction of the nozzle surface  20   a , and the Y direction. Namely, the first direction of the embodiment is the Y direction. 
     In addition, an extending direction of the first flow path  201  is a direction where the ink flows through the first flow path  201 . In the embodiment, since the first flow path  201  communicates with the second flow path  202  at one end in the Y direction, and communicates with the second common liquid chamber  102  at the other end in the Y direction, the ink flows through the first flow path  201  in the Y direction. Therefore, the extending direction of the first flow path  201  is the Y direction. 
     The first flow path  201  described above is provided between the second communication plate  152  and the nozzle plate  20  along the Y direction. Specifically, the first flow path  201  is formed by providing a recessed portion in the second communication plate  152  and covering an opening of the recessed portion with the nozzle plate  20 . Incidentally, the first flow path  201  is not specifically limited to being formed by the method, and may be formed by providing a recessed portion in the nozzle plate  20  and covering the recessed portion of the nozzle plate  20  with the second communication plate  152 , or may be formed by providing recessed portions in both of the second communication plate  152  and the nozzle plate  20 , respectively. 
     Herein, the first flow path  201  of the embodiment has a first portion  201   a  that is a portion having a first cross-sectional area as a cross-sectional area, and a second portion  201   b  that is a portion having a second cross-sectional area, which is smaller than the first cross-sectional area of the first portion  201   a , as a cross-sectional area. 
     Herein, the cross-sectional area of a flow path is the area of a cross section across a direction where the ink flows through the flow path. Therefore, the cross-sectional area of the first flow path  201  is the area of a cross section across the Y direction which is an ink flow direction. Namely, the direction of the first flow path  201  which is across the Y direction is a direction including the X direction and the Z direction, and the cross-sectional area of the first flow path  201  is the area of a cross section in the direction including the X direction and the Y direction. 
     In the embodiment, the first portion  201   a  and the second portion  201   b  are formed having the same width in the X direction. The second cross-sectional area of the second portion  201   b  is made smaller, compared to the first cross-sectional area of the first portion  201   a , by changing the height in the Z direction which is the normal direction of the nozzle surface  20   a . Specifically, as illustrated in  FIG. 3 , a height h 2  of the second portion  201   b  is smaller than a height h 1  of the first portion  201   a . In the embodiment, a difference in height between the first portion  201   a  and the second portion  201   b  is made, specifically, the height h 2  of the second portion  201   b  is made smaller than the height h 1  of the first portion  201   a  by positioning a ceiling, which is opposite to the nozzle  21  in the Z direction, of the second portion  201   b  closer to the nozzle plate  20  than a ceiling of the first portion  201   a.    
     The first portion  201   a  and the second portion  201   b  described above are disposed side by side in the Y direction which is the ink flow direction. In the embodiment, the first portion  201   a  is provided close to the second flow path  202 , and the second portion  201   b  is disposed close to the second common liquid chamber  102 . 
     The second flow path  202  is coupled to the first flow path  201 , and extends in the second direction, in the embodiment, extends in the Z direction other than the Y direction which is the first direction where the first flow path  201  extends. Herein, the extending direction of the second flow path  202  is a direction where the ink flows through the second flow path  202 . In the embodiment, since the second flow path  202  is provided to penetrate the communication plate  15  in the Z direction, communicates with the pressure chamber  12  at one end in the Z direction, and communicates with the first flow path  201  at the other end in the Z direction, the pressure chamber  12  communicates with the first flow path  201 . Therefore, the ink flows through the second flow path  202  in the Y direction. 
     The nozzle  21  may be disposed at a position in the middle of the first flow path  201  so as to communicate therewith. Namely, the nozzle  21  is provided such that one end of the nozzle  21  communicates with a portion in the middle of the first flow path  201  and the other end opens in the nozzle surface  20   a  of the nozzle plate  20  on the +Z side to communicate with the outside. 
     Herein, the fact that the nozzle  21  is provided in the middle of the first flow path  201  so as to communicate therewith implies that the nozzle  21  is disposed at a position to overlap the first flow path  201  in the plan view from the Z direction. By the way, the fact that the nozzle  21  is disposed at a position to overlap the second flow path  202  in the plan view from the Z direction does not imply that the nozzle  21  is provided in the middle of the first flow path  201  so as to communicate therewith. Namely, the first flow path  201  of the embodiment is a portion that does not overlap the second flow path  202  in the Z direction. 
     In addition, the nozzle  21  is provided at a position where the nozzle  21  communicates with the first portion  201   a  of the first flow path  201 . Namely, the first flow path  201  includes the first portion  201   a  that is closer to the second flow path  202  than the nozzle  21 , and the second portion  201   b  that is closer to the second common liquid chamber  102 , which is opposite to the second flow path  202 , than the nozzle  21 . Herein, the fact that the first flow path  201  includes the first portion  201   a  having the first cross-sectional area on a side closer to the second flow path  202  than the nozzle  21  implies that the first portion  201   a  includes also a portion communicating with the nozzle  21 . Namely, the configuration does not include a case where the nozzle  21  is provided at a position where the nozzle  21  communicates with the second portion  201   b . In addition, in the embodiment, the nozzle  21  is provided to communicate with a portion of the first portion  201   a  which is close to the second portion  201   b . Namely, the second portion  201   b  is provided proximate to a downstream portion of the nozzle  21 . 
     Incidentally, preferably, the cross-sectional area of the first flow path  201  communicating with the nozzle  21  is smaller than the cross-sectional area of the second flow path  202 . Namely, preferably, the first cross-sectional area of the first portion  201   a  of the first flow path  201  is smaller than the cross-sectional area of the second flow path  202 . In the embodiment, the cross-sectional area of the first portion  201   a  is made smaller than the cross-sectional area of the second flow path  202  by forming the first portion  201   a  and the second flow path  202  which have the same width in the X direction which is the direction where the nozzles  21  are arranged side by side, and making the height h 1  of the first portion  201   a  of the first flow path  201  in the Z direction smaller than a height h 3  of the second flow path  202  in the Y direction. 
     The individual flow path  200  described above has the supply path  203 , the pressure chamber  12 , the second flow path  202 , and the first flow path  201  in the order from an upstream region communicating with the first common liquid chamber  101  toward a downstream region communicating with the second common liquid chamber  102 . Namely, in the embodiment, in the individual flow path  200 , the pressure chamber  12  and the nozzle  21  are disposed in the order from the upstream region toward the downstream region with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 . 
     In the individual flow path  200  described above, the ink flows, namely, so-called circulation is performed from the first common liquid chamber  101  to the second common liquid chamber  102  through the individual flow path  200 . In addition, when a change in the pressure of the ink in the pressure chamber  12  is induced by driving the piezoelectric actuator  300 , and the pressure of the ink in the nozzle  21  is increased, ink droplets are discharged from the nozzle  21  to the outside. When the ink flows from the first common liquid chamber  101  to the second common liquid chamber  102  through the individual flow path  200 , the piezoelectric actuator  300  may be driven, and when the ink does not flow from the first common liquid chamber  101  to the second common liquid chamber  102  through the individual flow path  200 B, the piezoelectric actuator  300  may be driven. In addition, the ink may temporarily flow from the second common liquid chamber  102  to the first common liquid chamber  101  due to a pressure change induced by driving the piezoelectric actuator  300 . 
     In addition, in the recording head  1  of the embodiment, since the nozzle  21  communicates with a portion in the middle of the first flow path  201 , the ink flowing through the first flow path  201  enables the ink, which is dried and thickened by the nozzle  21 , to flow to the second common liquid chamber  102  in the downstream region. Therefore, the thickened ink is prevented from staying in the nozzle  21  and in the vicinity of the nozzle  21 , and thus it is possible to prevent the occurrence of a discharge defect such as the nozzle  21  being clogged by the thickened ink or a deviation in the flying direction of ink droplets discharged from the nozzle  21 . 
     On the other hand, for example, if the nozzle  21  is disposed at a position which permits communication with the second flow path  202 , namely, if the nozzle  21  is disposed at a position to overlap the second flow path  202  in the plan view from the Z direction, the ink dried and thickened by the nozzle  21  is likely to stay at corners between the second flow path  202  and the nozzle plate  20 , particularly, at a corner opposite to the first flow path  201  in the Y direction. A discharge defect such as the nozzle  21  being clogged by the thickened ink or a deviation in the flying direction of discharged ink droplets is likely to occur due to the thickened ink staying in the vicinity of the nozzle  21 . 
     In the embodiment, since the nozzle  21  communicates with the first flow path  201  extending in the Y direction, it is possible to dispose the nozzle  21  apart from the corner between the second flow path  202 , in which the ink is likely to stay, and the nozzle plate  20 , it is difficult for the ink thickened by the nozzle  21  to stay in the vicinity of the nozzle  21 , and it is easy to remove the thickened ink. 
     In addition, since the nozzle  21  communicates with a portion in the middle of the first flow path  201  extending in the Y direction, air bubbles infiltrating from the nozzle  21  are capable of flowing to the second common liquid chamber  102  in the downstream region by virtue of the ink flowing through the first flow path  201 . Therefore, air bubbles infiltrating from the nozzle  21  are prevented from entering the pressure chamber  12  or the first common liquid chamber  101 , and thus it is possible to prevent a defect in discharging ink droplets, which is caused due to a fluctuation in the pressure of the ink in the pressure chamber  12  being absorbed by air bubbles that infiltrate the pressure chamber  12 . By the way, if the nozzle  21  is provided at a position to communicate with the second flow path  202 , air bubbles infiltrating from the nozzle  21  are likely to move to the pressure chamber  12  against the flow of the ink due to the buoyancy of the air bubbles. If air bubbles infiltrate the pressure chamber  12  from the nozzle  21 , the air bubbles infiltrating the pressure chamber  12  absorb a fluctuation in the pressure of the ink in the pressure chamber  12 , and a defect in discharging ink droplets occurs, which is a concern. 
     In addition, if the first portion  201   a  having the first cross-sectional area is provided closer to the second flow path  202  than the nozzle  21 , an increase in flow path resistance from the pressure chamber  12  to the nozzle  21  is prevented, and thus it is possible to reduce a pressure loss from the pressure chamber  12  to the nozzle  21 , and it is possible to prevent a decrease in the weight of ink droplets to be discharged from the nozzle  21 . By the way, if the first flow path  201  is formed only of the second portion  201   b , since the flow path resistance from the pressure chamber  12  to the nozzle  21  is large and the pressure loss becomes large, the weight of ink droplets to be discharged from the nozzle  21  becomes small. For this reason, the piezoelectric actuator  300  has to be driven at a higher drive voltage, and discharge efficiency deteriorates. In the embodiment, since the nozzle  21  communicates with the first portion  201   a , it is possible to prevent a decrease in the weight of ink droplets, and thus it is possible to drive the piezoelectric actuator  300  at a lower drive voltage and to improve the discharge efficiency. In addition, if the nozzle  21  communicates with the first portion  201   a , there is no restriction in the position of the nozzle  21  that communicates a portion in the middle of the first flow path  201 . Namely, if the first flow path  201  is formed only of the second portion  201   b , in order to reduce the pressure loss from the pressure chamber  12  to the nozzle  21 , it is necessary to provide the nozzle  21  at a position close to the second flow path  202 . However, in the embodiment, since the first portion  201   a  includes the nozzle  21  and is provided closer to the second flow path  202  than the nozzle  21 , it is possible to reduce the pressure loss, and thus it is not necessary to dispose the nozzle  21  at a position close to the second flow path  202 , and it is possible to increase a degree of freedom in the disposition of the nozzle  21 . 
     In addition, since the second portion  201   b  is provided closer to the downstream region than the nozzle  21 , it is possible to increase the flow speed of the ink flowing the second portion  201   b , and the ink thickened by the nozzle  21  or air bubbles infiltrating from the nozzle  21  can be removed by the ink flowing through the second portion  201   b  at a relatively high flow speed. Namely, the ink thickened by the nozzle  21  or air bubbles infiltrating from the nozzle  21  easily flow toward the second portion  201   b  in the downstream region, and air bubbles flowing into the second portion  201   b  flow to the downstream region at a high flow speed, and thus it is difficult for the air bubbles to flow backward toward the second flow path  202  in the upstream region. Therefore, it is difficult for the thickened ink or the air bubbles to stay in the vicinity of the nozzle  21  and to flow backward to the upstream region. 
     In addition, in the embodiment, since the nozzle  21  communicates with the first portion  201   a  of the first flow path  201  which has a cross-sectional area smaller than that of the second flow path  202 , during the circulation of the ink, it is possible to further increase the flow speed of the ink flowing through the first flow path  201  directly above the nozzle  21  compared to the flow speed of the ink flowing through the second flow path  202 , and thus the ink flowing through the first flow path  201  enables the ink, which is thickened by the nozzle  21 , or air bubbles, which infiltrate from the nozzle  21 , to easily flow to the second common liquid chamber  102  in the downstream region. Therefore, the thickened ink or the infiltrated air bubbles have a reduced possibility of staying in the vicinity of the nozzle  21 , and thus it is possible to prevent the occurrence of a defect in discharging ink droplets. 
     By the way, for example, it is possible to consider also a configuration where the nozzle  21  is provided at a position to communicate with the second flow path  202 , and the flow speed of a portion of the second flow path  202  which is close to the nozzle  21  is increased by making the cross-sectional area of the portion of the second flow path  202  which is close to the nozzle  21  smaller than the cross-sectional area of a portion close to the pressure chamber  12 , and thus the thickened ink flows downstream. However, even in the configuration described above, air bubbles infiltrating from the nozzle  21  infiltrate the pressure chamber  12  against the flow of the ink due to the buoyancy of the air bubbles, which is a concern. In the embodiment, since the extending direction of the first flow path  201 , in the middle of which the nozzle  21  communicates with a portion, is a direction intersecting the Z direction which is a vertical direction, it is possible to prevent air bubbles from infiltrating the pressure chamber  12 . 
     Incidentally, in the embodiment, the first flow path  201  and the second common liquid chamber  102  of the individual flow path  200  are directly coupled to each other; however, the present disclosure is not specifically limited to the configuration. Another flow path may be provided between the first flow path  201  and the second common liquid chamber  102 . For example, if another flow path is provided between the first flow path  201  and the second common liquid chamber  102 , preferably, the distance in the first flow path  201  from the nozzle  21  to the second flow path  202  is shorter than a distance in the first flow path  201  from the nozzle  21  to the other flow path. 
     Incidentally, preferably, the flow path resistance from the nozzle  21  to the pressure chamber  12  is smaller than the flow path resistance from the nozzle  21  to the second common liquid chamber  102 . Namely, preferably, the flow path resistance of a portion of the first flow path  201  which is upstream of the position where the first flow path  201  communicates with the nozzle  21 , and the second flow path  202  are smaller than the flow path resistance of a portion of the first flow path  201  which is downstream of the position where the first flow path  201  communicates with the nozzle  21 . Accordingly, the pressure loss from the pressure chamber  12  to the nozzle  21  is reduced, and thus it is possible to prevent a decrease in the weight of ink droplets to be discharged from the nozzle  21 , and it is possible to improve discharge efficiency. 
     In addition, in the individual flow path  200 , preferably, the flow path resistance from the nozzle  21  to the second common liquid chamber  102  is in a range from −50% to +50% with respect to the flow path resistance from the nozzle  21  to the first common liquid chamber  101 . 
     Namely, the flow path resistance from the nozzle  21  to the first common liquid chamber  101  is the flow path resistance of the portion of the first flow path  201 , which is from the position where the first flow path  201  communicates with the nozzle  21  to a position close to the second flow path  202 , the second flow path  202 , and the supply path  203 . In addition, the flow path resistance from the nozzle  21  to the second common liquid chamber  102  is the flow path resistance of a portion from the position where the first flow path  201  communicates with the nozzle  21  to the second common liquid chamber  102 . If in the individual flow path  200 , the flow path resistance from the nozzle  21  to the second common liquid chamber  102  is set in a range from −50% to +50% with respect to the flow path resistance from the nozzle  21  to the first common liquid chamber  101 , it is easy to manage the position of the meniscus of the ink of the nozzle  21 . For example, if the direction of circulation is reversed with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 , namely, even though the ink flows from the second common liquid chamber  102  toward the first common liquid chamber  101 , if the flow path resistance is set as described above, it is easy to align the position of the meniscus of the ink in the nozzle  21 . By the way, preferably, the flow path resistance from the nozzle  21  to the first common liquid chamber  101  is made equal to the flow path resistance from the nozzle  21  to the second common liquid chamber  102 . Accordingly, it is further easy to align the position of the meniscus of the ink of the nozzle  21 . 
     As described above, the ink jet type recording head  1  which is one example of the liquid ejecting head of the embodiment includes a flow path substrate which includes the nozzle plate  20  and in which a flow path is formed, and the piezoelectric actuator  300  which is an energy generating element for inducing a change in the pressure of an ink which is a liquid in the flow path. The flow path includes the first common liquid chamber  101 ; the second common liquid chamber  102 ; and the plurality of individual flow paths  200  which communicate with the first common liquid chamber  101  and the second common liquid chamber  102  and through which the ink flows from the first common liquid chamber  101  toward the second common liquid chamber  102 . The individual flow path  200  includes the nozzle  21  that communicates with the outside; the first flow path  201 , in the middle of which the nozzle  21  is disposed and which extends in the Y direction that is the first direction which is the in-plane direction of the nozzle surface  20   a  of the nozzle plate  20  in which the nozzle  21  opens; the second flow path  202  that is coupled to the first flow path  201  and extends in the Z direction which is the second direction other than the Y direction; the third flow path that is coupled to the second flow path  202  and extends in the Y direction which is the third direction other than the Z direction; and the pressure chamber  12  which is disposed in the third flow path and in which a pressure change is induced by the piezoelectric actuator  300 . The first flow path  201  includes the first portion  201   a , which is a portion having the first cross-sectional area, on the side closer to the second flow path  202  than the nozzle  21 , and the second portion  201   b , which is a portion having the second cross-sectional area that is smaller than the first cross-sectional area, on a side that is opposite to the second flow path  202  across the nozzle  21 . 
     As described above, since the nozzle  21  communicates with a portion in the middle of the first flow path  201  extending in the Y direction, the ink flowing through the first flow path  201  enables the ink, which is dried and thickened by the nozzle  21 , to flow to the second common liquid chamber  102  in the downstream region. Therefore, it is possible to dispose the nozzle  21  apart from a portion, for example, the corner between the second flow path  202  and the nozzle plate  20 , in which the ink stays, and the ink thickened by the nozzle  21  is prevented from staying at the corner between the second flow path  202  and the nozzle plate  20 , and thus it is possible to prevent the occurrence of a discharge defect such as the nozzle  21  being clogged by the thickened ink or air bubbles, or a deviation in the flying direction of ink droplets discharged from the nozzle  21 . In addition, air bubbles infiltrating from the nozzle  21  can be prevented from staying at the corner between the second flow path  202  and the nozzle plate  20 , and the air bubbles infiltrating from the nozzle  21  are prevented from moving to the pressure chamber  12 , and thus it is possible to prevent a defect in discharge ink droplets. 
     In addition, since the first portion  201   a  having the first cross-sectional area is provided closer to the second flow path than the nozzle  21 , it is possible to reduce the pressure loss from the pressure chamber  12  to the nozzle  21 , and to prevent a decrease in the weight of ink droplets to be discharged from the nozzle  21 . 
     Furthermore, since the second portion  201   b  having the second cross-sectional area is provided closer to the second common liquid chamber  102  than the nozzle  21 , it is possible to increase the flow speed of the ink flowing the second portion  201   b , the ink thickened by the nozzle  21  or air bubbles infiltrating from the nozzle  21  can be removed by the ink flowing through the second portion  201   b  at a relatively high flow speed, and it is difficult for the thickened ink or the air bubbles to flow backward to the upstream region. 
     In addition, in the recording head  1  of the embodiment, preferably, the cross-sectional area of the first flow path  201  is smaller than the cross-sectional area of the second flow path  202 . Namely, preferably, the first cross-sectional area of the first portion  201   a  which is small between the cross-sectional areas of the first flow path  201  is smaller than the area of a cross section of the second flow path  202  which is across the flow of the ink. As described above, since the nozzle  21  communicates with the first portion  201   a  of the first flow path  201  which has a cross-sectional area smaller than that of the second flow path  202 , during the circulation of the ink, it is possible to further increase the flow speed of the ink flowing through the first flow path  201  directly above the nozzle  21  compared to the flow speed of the ink flowing through the second flow path  202 , and thus the ink flowing through the first flow path  201  enables the ink, which is thickened by the nozzle  21 , or air bubbles, which infiltrate from the nozzle  21 , to easily flow to the second common liquid chamber  102  in the downstream region. Therefore, the thickened ink or the infiltrated air bubbles have a reduced possibility of staying in the vicinity of the nozzle  21 , and thus it is possible to prevent the occurrence of a defect in discharging ink droplets. 
     In addition, in the recording head  1  of the embodiment, the second portion  201   b  which is a portion having the second cross-sectional area is formed to have a smaller cross-sectional area than the first portion  201   a  by reducing the height of the first portion  201   a , which is a portion having the first cross-sectional area, in the Z direction which is the normal direction of the nozzle surface  20   a  in which the nozzle  21  opens. As described above, if the second portion  201   b  is formed by not reducing the width in the X direction where the nozzles  21  are arranged side by side but reducing the height in the Z direction, it is possible to dispose the first flow paths  201  in the X direction at a high density without forming the first portion  201   a  having a wide width in the X direction, and it is possible to improve the rigidity of a wall between the first flow paths  201  adjacent to each other in the X direction, and thus it is possible to prevent the occurrence of variations in the discharge characteristics of ink droplets, which is caused due to the wall being deformed by the pressure of the ink in the flow path. Namely, if ink droplets are simultaneously discharged from the nozzles  21  on both sides of the nozzle  21  discharging ink droplets, pressures are applied, at the same timing, from both sides to the wall between the first flow paths  201  adjacent to each other. In this case, since the pressures are applied from both sides to the wall, regardless of the rigidity of the wall, it is difficult for the wall to be deformed. On the other hand, if ink droplets are not discharged from the nozzles  21  on both sides of the nozzle  21  discharging ink droplets, a pressure is applied only to one side of the wall between the first flow paths  201  adjacent to each other. At that time, if the rigidity of the wall is low, the wall is deformed to absorb a pressure fluctuation, and the discharge characteristics of the ink droplets deteriorate. For this reason, variations in the discharge characteristics of ink droplets occur depending on a difference in condition such as which nozzle discharging ink droplets among the plurality of nozzles  21 . In the embodiment, since the second portion  201   b  of the first flow path  201  is formed by not changing the width of the first portion  201   a  in the X direction but reducing the height of the first portion  201   a  in the Z direction, it is possible to prevent a reduction in the rigidity of a wall between the second portions  201   b  adjacent to each other in the X direction, and thus it is possible to prevent the occurrence of variations in the discharge characteristics of ink droplets. 
     In addition, in the individual flow path  200  of the recording head  1  of the embodiment, preferably, the flow path resistance of the region upstream of the nozzle  21  is in a range from −50% to +50% with respect to the flow path resistance of the region downstream thereof. As described above, if in the individual flow path  200 , the flow path resistance of the region downstream thereof is set in a range from −50% to +50% with respect to the flow path resistance of the region upstream of the nozzle  21 , regardless of the direction where the ink flows through the individual flow path  200 , it is easy to manage the position of the meniscus of the ink of the nozzle  21 . 
     Incidentally, in the embodiment, the first portion  201   a  is formed and a step surface which is a surface along the Z direction is formed in a portion, in which the height in the Z direction differs between the first portion  201   a  and the second portion  201   b , by reducing the height of the first flow path  201  which is a height in the Z direction on one side opposite to the nozzle  21 ; however, the present disclosure is not specifically limited to the configuration. Herein, a modification example of the first flow path  201  of the embodiment is illustrated in  FIG. 4 . Incidentally,  FIG. 4  is an enlarged cross-sectional view of a main part illustrating the modification example of the first flow path according to Embodiment 1 of the present disclosure, which is taken along the line IV-IV in  FIG. 1 . 
     As illustrated in  FIG. 4 , the second portion  201   b  is formed by lowering a ceiling of the first portion  201   a  which is opposite to the nozzle  21  in the Z direction. In addition, a coupling portion having a reduced height between the first portion  201   a  and the second portion  201   b  is an inclined surface  201   c  that is inclined with respect to the normal direction of the nozzle surface  20   a . Namely, the inclined surface  201   c  is formed in the ceiling such that the height in the Z direction is gradually reduced in the Y direction from the first portion  201   a  toward the second portion  201   b.    
     As described above, since the inclined surface  201   c  is provided in a ceiling of the coupling portion between the first portion  201   a  and the second portion  201   b , even though an air bubble  210  from the second portion  201   b  rises upward to the vicinity of the ceiling due to buoyancy, by virtue of the ink flowing through the first flow path  201 , the air bubble  210  is capable of moving to the downstream region along the inclined surface  201   c , and it is possible to prevent the air bubble  210  from staying in the vicinity of the nozzle  21 . By the way, in the configuration described above and illustrated in  FIG. 3 , a step having a surface along the Z direction is provided in a ceiling portion which couples the first portion  201   a  to the second portion  201   b , air bubbles move to the ceiling due to buoyancy and are caught by the step, and thus the air bubbles do not flow downstream, which is a concern. 
     In addition, the second portion  201   b  is formed by lowering the ceiling opposite to the nozzle  21  in the Z direction; however, the present disclosure is not specifically limited to the configuration. Herein, a modification example of the first flow path  201  is illustrated in  FIG. 5 . Incidentally,  FIG. 5  is an enlarged cross-sectional view of a main part illustrating the modification example of the first flow path according to Embodiment 1 of the present disclosure, which is taken along the line V-V in  FIG. 1 . 
     As illustrated in  FIG. 5 , the first portion  201   a  of the first flow path  201  is formed by lowering a bottom surface, in which the nozzle  21  is provided, in the normal direction of the nozzle surface  20   a . Namely, a ceiling portion of a coupling portion between the first portion  201   a  and the second portion  201   b  is flush with the ceilings thereof. In the first flow path  201  described above, even though air bubbles infiltrating from the nozzle  21  move in the −Z direction due to buoyancy, the air bubbles are prevented from staying in the coupling portion between the first portion  201   a  and the second portion  201   b , and thus it is possible to prevent a discharge defect which is caused due to the air bubbles staying in the vicinity of the nozzle  21 . 
     In addition, the embodiment employs a configuration where the nozzle plate  20  and the compliance substrate  49  are provided as separate bodies; however, the present disclosure is not specifically limited to the configuration. For example, the nozzle plate  20  may be provided having a size to cover the opening of the first common liquid chamber  101 , and the compliance portion  494  may be provided in part of the nozzle plate  20 . The nozzle plate  20  provided with the compliance portion  494  as described above can be manufactured of a resin film such as a polyimide film or a metallic material such as stainless steel. 
     Embodiment 2 
       FIG. 6  is a cross-sectional view of an ink jet type recording head which is one example of a liquid ejecting head according to Embodiment 2 of the present disclosure which is taken along the line VI-VI in  FIG. 1 .  FIG. 7  is a cross-sectional view of a main part which is taken along a line VII-VII in  FIG. 6 . Incidentally, the same reference signs are assigned to the same members as those in the embodiment described above, and the duplicated description will be omitted. 
     As illustrated in  FIGS. 6 and 7 , the first flow path  201  has the first portion  201   a  having the first cross-sectional area on the side closer to the second flow path  202  than the nozzle  21 , and the second portion  201   b  having the second cross-sectional area, which is smaller than the first cross-sectional area, on the side closer to the second common liquid chamber  102  than the nozzle  21 . 
     As illustrated in  FIG. 7 , the second portion  201   b  is formed by reducing the width of the first portion  201   a  in the X direction which is the direction where the nozzles  21  are arranged side by side. Namely, a width w 2  of the second portion  201   b  in the X direction is narrower than a width w 1  of the first portion  201   a  in the X direction. In addition, in the embodiment, the width of the second portion  201   b  in the X direction is formed by reducing the first portion  201   a  from both sides in the X direction. 
     Incidentally, the first portion  201   a  and the second portion  201   b  are provided having the same height in the Z direction. 
     As described above, the ink jet type recording head  1  which is one example of the liquid ejecting head of the embodiment includes a flow path substrate which includes the nozzle plate  20  and in which a flow path is formed, and the piezoelectric actuator  300  which is an energy generating element for inducing a change in the pressure of an ink which is a liquid in the flow path. The flow path includes the first common liquid chamber  101 ; the second common liquid chamber  102 ; and the plurality of individual flow paths  200  which communicate with the first common liquid chamber  101  and the second common liquid chamber  102  and through which the ink flows from the first common liquid chamber  101  toward the second common liquid chamber  102 . The individual flow path  200  includes the nozzle  21  that communicates with the outside; the first flow path  201 , in the middle of which the nozzle  21  is disposed and which extends in the Y direction that is the first direction which is the in-plane direction of the nozzle surface  20   a  of the nozzle plate  20  in which the nozzle  21  opens; the second flow path  202  that is coupled to the first flow path  201  and extends in the Z direction which is the second direction other than the Y direction; the third flow path that is coupled to the second flow path  202  and extends in the Y direction which is the third direction other than the Z direction; and the pressure chamber  12  which is disposed in the third flow path and in which a pressure change is induced by the piezoelectric actuator  300 . The first flow path  201  includes the first portion  201   a , which is a portion having the first cross-sectional area, on the side closer to the second flow path  202  than the nozzle  21 , and the second portion  201   b , which is a portion having the second cross-sectional area that is smaller than the first cross-sectional area, on the side that is opposite to the second flow path  202  across the nozzle  21 . 
     As described above, since the nozzle  21  communicates with a portion in the middle of the first flow path  201  extending in the Y direction, the ink flowing through the first flow path  201  enables the ink, which is dried and thickened by the nozzle  21 , to flow to the second common liquid chamber  102  in the downstream region. Therefore, it is possible to dispose the nozzle  21  apart from a portion, for example, the corner between the second flow path  202  and the nozzle plate  20 , in which the ink stays, and the ink thickened by the nozzle  21  is prevented from staying at the corner between the second flow path  202  and the nozzle plate  20 , and thus it is possible to prevent the occurrence of a discharge defect such as the nozzle  21  being clogged by the thickened ink or air bubbles, or a deviation in the flying direction of ink droplets discharged from the nozzle  21 . In addition, air bubbles infiltrating from the nozzle  21  can be prevented from staying at the corner between the second flow path  202  and the nozzle plate  20 , and the air bubbles infiltrating from the nozzle  21  are prevented from moving to the pressure chamber  12 , and thus it is possible to prevent a defect in discharge ink droplets. 
     In addition, since the first portion  201   a  having the first cross-sectional area is provided closer to the second flow path than the nozzle  21 , it is possible to reduce the pressure loss from the pressure chamber  12  to the nozzle  21 , and to prevent a decrease in the weight of ink droplets to be discharged from the nozzle  21 . 
     Furthermore, since the second portion  201   b  having the second cross-sectional area is provided closer to the second common liquid chamber  102  than the nozzle  21 , it is possible to increase the flow speed of the ink flowing the second portion  201   b , the ink thickened by the nozzle  21  or air bubbles infiltrating from the nozzle  21  can be removed by the ink flowing through the second portion  201   b  at a relatively high flow speed, and it is difficult for the thickened ink or the air bubbles to flow backward to the upstream region. 
     In addition, in the recording head  1  of the embodiment, the second portion  201   b  which is a portion having the second cross-sectional area is formed to have a cross-sectional area smaller than the first cross-sectional area of the first portion  201   a  by reducing the width of the first portion  201   a , which is a portion having the first cross-sectional area, in the X direction which is the direction where the nozzles  21  are arranged side by side. As described above, since the second portion  201   b  is provided by reducing the width in the X direction, it is possible to prevent an increase in the height of the first portion  201   a  in the Z direction. Therefore, it is possible to reduce the thickness of the communication plate  15  in the Z direction to a relatively small thickness. Accordingly, the flow path length of the second flow path  202  is relatively shortened, and thus the pressure loss from the pressure chamber  12  to the nozzle  21  is reduced, and it is possible to prevent a decrease in the weight of ink droplets to be discharged from the nozzle  21 . 
     In addition, since the width of the second portion  201   b  in the X direction is reduced, a step is not formed at a ceiling, which is opposite to the nozzle  21  in the Z direction, in a coupling portion between the first portion  201   a  and the second portion  201   b . Therefore, the step is prevented from causing air bubbles to stay in the vicinity of the nozzle  21 , and thus it is possible to prevent the occurrence of a discharge defect which is caused by the air bubbles. 
     Incidentally, in the embodiment, the second portion  201   b  is formed by reducing the width of the first portion  201   a  in the X direction from both sides, but is not specifically limited to being formed by the method. The second portion  201   b  may be formed by reducing the width in the X direction from one side. Herein, in a case where a single crystal silicon substrate, in which a surface plane orientation is preferentially aligned in a (100) plane, is used as the communication plate  15 , the first flow path  201  will be described with reference to  FIG. 8 . Incidentally,  FIG. 8  is a cross-sectional view illustrating a modification example of the first flow path which is taken along the line VIII-VIII in  FIG. 6 . 
     As illustrated in  FIG. 8 , the communication plate  15  is made of a single crystal silicon substrate in which the surface plane orientation is preferentially aligned in a (110) plane. It is possible to form the first portion  201   a  and the second portion  201   b  of the first flow path  201  with a high accuracy by performing anisotropic etching (referred to also as wet etching) on the communication plate  15  using an alkaline solution. 
     Herein, anisotropic etching is performed by using a difference between the etching rates of the single crystal silicon substrate. Namely, anisotropic etching is performed by using the property that in the single crystal silicon substrate having the surface plane orientation in the (110) plane, the etching rate of a (111) plane is approximately 1/180 compared to the etching rate of the (110) plane. Namely, if the single crystal silicon substrate in which the surface plane orientation is preferentially aligned in the (110) plane is immersed in an alkaline solution such as a potassium hydroxide aqueous solution (KOH) or tetramethylammonium hydroxide (TMAH), the single crystal silicon substrate is gradually eroded, and there appear a first (111) plane perpendicular to the (110) plane, and a second (111) plane that forms an angle of 70.53 degrees with the first (111) plane and an angle of 37.5 degrees with the (110) plane. With the anisotropic etching, it is possible to perform precision machining based on a parallelogram formed by the first (111) planes which are two parallel planes and the second (111) planes which are two parallel planes. In the embodiment, the second portion  201   b  is formed by reducing the width of the first portion  201   a  in the X direction from one side such that no sharp corner is formed in the coupling portion between the first portion  201   a  and the second portion  201   b  of the first flow path  201 . Namely, the second portion  201   b  is not formed so as to overlap the first portion  201   a  in the plan view from the X direction. Accordingly, an obtuse corner is formed in the coupling portion between the first portion  201   a  and the second portion  201   b , and thus the air bubble  210  is prevented from being caught by a corner between the first portion  201   a  and the second portion  201   b , and the air bubble  210  is prevented from staying in the first portion  201   a , thereby being capable of improving the outflow of the air bubbles. On the other hand, for example, as illustrated in  FIG. 9 , if a sharp corner is formed in the coupling portion between the first portion  201   a  and the second portion  201   b , it is difficult for the air bubble  210  to pass over the sharp corner from the first portion  201   a , and to move to the second portion  201   b . Therefore, the air bubble  210  stays in the vicinity of the nozzle  21 , and there occurs a defect in discharging ink droplets due to the air bubble  210 , which is a concern. 
     Embodiment 3 
       FIG. 10  is a plan view of an ink jet type recording head which is one example of a recording head according to Embodiment 3 of the present disclosure.  FIG. 11  is a cross-sectional view taken along a line XI-XI in  FIG. 10 .  FIG. 12  is a cross-sectional view taken along a line XII-XII in  FIG. 10 .  FIG. 13  is a diagram schematically illustrating a flow path configuration according to Embodiment 3. Incidentally, the same reference signs are assigned to the same members as those in the embodiment described above, and the duplicated description will be omitted. 
     As illustrated in  FIGS. 11 and 12 , the flow path formation substrate  10 , the communication plate  15 , the nozzle plate  20 , the compliance substrate  49 , the case member  40 , and the like which are flow path substrates are provided with the first common liquid chamber  101 , the second common liquid chamber  102 , and a plurality of the individual flow paths  200  through which an ink flows from the first common liquid chamber  101  to the second common liquid chamber  102 . 
     Two rows of the pressure chambers  12  which are arranged side by side in the X direction are arranged side by side in the flow path formation substrate  10  in the Y direction. In addition, in two rows of the pressure chambers  12 , the pressure chamber  12  in one row is referred to as a first pressure chamber  12 A, and the pressure chamber  12  in the other row is referred to as a second pressure chamber  12 B. The first pressure chamber  12 A and the second pressure chamber  12 B are disposed at positions which do not overlap each other in a plan view from the X direction. In addition, the first pressure chambers  12 A and the second pressure chambers  12 B are disposed in a so-called staggered pattern where the first pressure chambers  12 A deviate from the second pressure chamber  12 B in the X direction. In the embodiment, the row in which the first pressure chambers  12 A are arranged side by side in the X direction, and the row in which the second pressure chambers  12 B are arranged side by side in the X direction are disposed at positions which deviate by half a pitch from each other in the X direction. Incidentally, part of the first pressure chamber  12 A and part of the second pressure chamber  12 B may be disposed at positions which overlap each other in the plan view from the first direction X. 
     In addition, in the embodiment, the nozzle  21  communicating with the first pressure chamber  12 A is referred to as a first nozzle  21 A, and the nozzle  21  communicating with the second pressure chamber  12 B is referred to as a second nozzle  21 B. In the embodiment, as illustrated in  FIG. 10 , in the nozzle row  22 , the first nozzle  21 A and the second nozzle  21 B are alternately disposed in the X direction. In addition, in the embodiment, the first nozzle  21 A and the second nozzle  21 B are disposed at the same position in the Y direction. Namely, the nozzles  21  are disposed on a straight line along the X direction. Incidentally, the first nozzle  21 A and the second nozzle  21 B may be disposed so as not to be at the same position in the second direction Y. Namely, two nozzle rows including a nozzle row where the first nozzles  21 A are arranged side by side and a nozzle row where the second nozzles  21 B are arranged side by side may be provided. 
     In addition, as illustrated in  FIGS. 11 and 12 , the communication plate  15  is provided with the first communication portion  16  forming the first common liquid chamber  101 , and a fourth communication portion  19  forming the second common liquid chamber  102 . 
     Since the first communication portion  16  is the same as that in the Embodiment 1, the duplicated description will be omitted. 
     The fourth communication portion  19  is provided at a position to overlap the second liquid chamber portion  42  of the case member  40  in the Z direction, and is provided to be open in both of the +Z and −Z side surfaces of the communication plate  15 , namely, is provided to penetrate the communication plate  15  in the Z direction. The fourth communication portion  19  communicates with the second liquid chamber portion  42  on the −Z side to form the second common liquid chamber  102 . Namely, the second common liquid chamber  102  is formed of the second liquid chamber portion  42  of the case member  40  and the fourth communication portion  19  of the communication plate  15 . In addition, the fourth communication portion  19  extends on the +Z side in the Y direction to a position to overlap the second pressure chamber  12 B in the Z direction. 
     In addition, the compliance substrate  49  is provided on an open surface of the second common liquid chamber  102  on the +Z side, and part of a wall surface of the second common liquid chamber  102  becomes the compliance portion  494 . In the embodiment, the compliance portion  494  provided in the first common liquid chamber  101  is referred to as a first compliance portion  494 A, and the compliance portion  494  provided in the second common liquid chamber  102  is referred to as a second compliance portion  494 B. As described above, if the compliance portion  494  is provided in part of the wall surface of each of the first common liquid chamber  101  and the second common liquid chamber  102 , the compliance portion  494  is capable of, by being deformed, absorbing a fluctuation in the pressure of the ink in the first common liquid chamber  101  and the second common liquid chamber  102 . 
     By the way, if the second compliance portion  494 B is not provided and only the first compliance portion  494 A is provided, a pressure fluctuation when ink droplets are discharged in an individual flow path which is provided with the pressure chamber  12  and the nozzle  21  is transmitted to another individual flow path via the second common liquid chamber  102 , and thus the discharge characteristics of ink droplets discharged from the other individual flow path are not stable, and there occur variations in the discharge characteristics of ink droplets discharged from the plurality of nozzles  21 , which is a concern. Similarly, if the first compliance portion  494 A is not provided and only the second compliance portion  494 B is provided, a pressure fluctuation of the individual flow path is transmitted via the first common liquid chamber  101 , and there occur variations in the discharge characteristics of ink droplets, which is a concern. In the embodiment, since the compliance portions are provided in both of the first common liquid chamber  101  and the second common liquid chamber  102 , it is difficult for a pressure fluctuation of an individual flow path to be transmitted to another individual flow path via the first common liquid chamber  101  and the second common liquid chamber  102 , and it is possible to prevent the occurrence of variations in the discharge characteristics of ink droplets. 
     In addition, if the second compliance portion  494 B is not provided and only the first compliance portion  494 A is provided, when ink droplets are discharged from a small number of the nozzles  21 , the ink is sufficiently supplied to the pressure chambers  12  by the deformation of the first compliance portions  494 A. However, when ink droplets are simultaneously discharged from a large number of the nozzles  21 , the ink is not sufficiently supplied to the pressure chambers  12  only by the deformation of the first compliance portions  494 A, and depending on the number of the nozzles  21  that simultaneously discharge the ink, there occur variations in the discharge characteristics of ink droplets, particularly, in the weight of ink droplets, which is a concern. In the embodiment, since both of the first compliance portion  494 A and the second compliance portion  494 B are provided, the occurrence of a shortage of ink supply to the pressure chamber  12  is prevented which is caused by the number of the nozzles  21  that simultaneously discharge ink droplets, and thus it is possible to prevent the occurrence of variations in the discharge characteristics of ink droplets. 
     In addition, as described above, if the compliance portion  494  is provided in both of the first common liquid chamber  101  and the second common liquid chamber  102 , in the embodiment, since the first common liquid chamber  101  and the second common liquid chamber  102  are provided so as to open on the +Z side on which the nozzle  21  opens, the nozzle plate  20  and the compliance portion  494  are disposed on the +Z side which is the same side with respect to the individual flow path  200  having the pressure chamber  12  and the nozzle  21  in the Z direction which is the normal direction of the nozzle surface  20   a . As described above, if the compliance portion  494  is disposed on the same side as the nozzle  21  with respect to the individual flow path  200 , it is possible to provide the compliance portion  494  in a region where the nozzle  21  is not provided, and it is possible to provide the compliance portion  494  having a relatively wide area. In addition, if the compliance portion  494  and the nozzle  21  are disposed on the same side with respect to the individual flow path  200 , the compliance portion  494  is disposed at a position close to the individual flow path  200 , and thus the compliance portion  494  is capable of effectively absorbing a fluctuation in the pressure of the ink in the individual flow path  200 . 
     Incidentally, the position of the compliance portion  494  is not specifically limited to the position, and the compliance portion  494  may be disposed opposite to the nozzle  21  with respect to the individual flow path  200  in the Z direction. Namely, it is also possible to provide the compliance portion  494  on a −Z side surface of the case member  40 , side surfaces of the case member  40  and the communication plate  15 , or the like. However, as described above, since the compliance portion  494  is disposed on the same +Z side as the nozzle  21 , the compliance portion  494  is disposed at a position close to the individual flow path  200 , and thus the compliance portion  494  is capable of effectively absorbing a fluctuation in the pressure of the ink in the individual flow path  200 , and the compliance portion  494  can be formed having a relatively wide area. 
     In addition, two compliance portions  494  of the embodiment are provided, as illustrated in  FIG. 10 , in one compliance substrate  49 . Naturally, the compliance substrate  49  is not limited to the configuration, and the compliance substrate  49  may be independently provided for each of the compliance portions  494 . 
     In addition, the individual flow path  200  of the embodiment includes a first individual flow path  200 A having the first nozzle  21 A, and a second individual flow path  200 B having the second nozzle  21 B. The first individual flow path  200 A and the second individual flow path  200 B are alternately disposed in the X direction. 
     Herein, as illustrated in  FIG. 11 , the first individual flow path  200 A includes the first nozzle  21 A; the first pressure chamber  12 A; a first flow path  201 A; a second flow path  202 A; a first supply path  203 A; a fourth flow path  204 A; and a fifth flow path  205 A. 
     The first supply path  203 A is a flow path through which the first pressure chamber  12 A communicates with the first common liquid chamber  101 , and is provided to penetrate the first communication plate  151  in the Z direction, namely, extends along the Z direction. 
     The first pressure chamber  12 A forms the third flow path that extends in the direction other than the Z direction. The third flow path of the first individual flow path  200 A of the embodiment is formed only of the first pressure chamber  12 A. The first pressure chamber  12 A is, as described above, provided in the flow path formation substrate  10 . In addition, the first pressure chamber  12 A forms a first resolution in the X direction which is a direction where the flow paths are arranged. Incidentally, since the first pressure chamber  12 A and the second pressure chamber  12 B are disposed at different positions in the Y direction, the first resolution is the resolution of each of the first pressure chamber  12 A and the second pressure chamber  12 B. In addition, the first resolution is a pitch of the flow paths in the X direction which is the direction where the flow paths are arranged. 
     Similar to Embodiment 1 described above, the first flow path  201 A extends between the nozzle plate  20  and the communication plate  15  in the Y direction which is the first direction. The first flow path  201 A of the embodiment is formed by providing a recessed portion in the second communication plate  152  and covering an opening of the recessed portion with the nozzle plate  20 . Incidentally, the first flow path  201 A is not specifically limited to being formed by the method, and may be formed by providing a recessed portion in the nozzle plate  20  and covering the recessed portion of the nozzle plate  20  with the second communication plate  152 , or may be formed by providing recessed portions in both of the second communication plate  152  and the nozzle plate  20 , respectively. 
     The first nozzle  21 A is disposed in the middle of the first flow path  201 A so as to communicate therewith. 
     In addition, the first flow path  201 A has the first portion  201   a  having the first cross-sectional area on a side closer to the second flow path  202  than the first nozzle  21 A, and the second portion  201   b  having the second cross-sectional area, which is smaller than the first cross-sectional area, on a side closer to the second common liquid chamber  102  than the first nozzle  21 A. In the embodiment, similar to Embodiment 1 described above, the second portion  201   b  is formed by reducing the height of the first portion  201   a  in the Z direction. Naturally, the second portion  201   b  is not limited to being formed by the method, and similar to Embodiment 2, the second portion  201   b  may be formed by reducing the width of the first portion  201   a  in the X direction. 
     Similar to Embodiment 1 described above, the second flow path  202 A is coupled to the first flow path  201 A, and extends in the second direction, in the embodiment, extends in the Z direction other than the Y direction which is the first direction where the first flow path  201 A extends. The second flow path  202 A is provided to penetrate the communication plate  15  in the Z direction, communicates with the first pressure chamber  12 A at one end in the Z direction, and communicates with the first flow path  201 A at the other end in the Z direction. 
     The fourth flow path  204 A is provided to penetrate the second communication plate  152  in the third direction such that one end of the fourth flow path  204 A communicates with the first flow path  201 A and the other end communicates with the fifth flow path  205 A. Namely, the fourth flow path  204 A extends in the Z direction different from the Y direction which is the first direction where the first flow path  201 A extends. 
     The fifth flow path  205 A extends between the first communication plate  151  and the second communication plate  152  along the Y direction in the in-plane direction of the nozzle surface  20   a  such that one end of the fifth flow path  205 A communicates with the fourth flow path  204 A and the other end communicates with the second common liquid chamber  102 . The fifth flow path  205 A of the embodiment is formed by providing a recessed portion in the second communication plate  152  and covering the recessed portion with the first communication plate  151 . Naturally, the fifth flow path  205 A may be formed by providing a recessed portion in the first communication plate  151  and covering the recessed portion with the second communication plate  152 , or may be formed by providing recessed portions in both of the first communication plate  151  and the second communication plate  152 , respectively. 
     As described above, the first individual flow path  200 A has the first supply path  203 A, the first pressure chamber  12 A, the second flow path  202 A, the first flow path  201 A, the first nozzle  21 A, the fourth flow path  204 A, and the fifth flow path  205 A in the order from an upstream region communicating with the first common liquid chamber  101  toward a downstream region communicating with the second common liquid chamber  102 . Namely, in the embodiment, as illustrated in  FIG. 13 , in the first individual flow path  200 A, the first pressure chamber  12 A and the first nozzle  21 A are disposed in the order from the upstream region toward the downstream region with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 . 
     In the first individual flow path  200 A described above, the ink flows from the first common liquid chamber  101  to the second common liquid chamber  102  through the first individual flow path  200 A. In addition, when a change in the pressure of the ink in the first pressure chamber  12 A is induced by driving the piezoelectric actuator  300 , and the pressure of the ink in the first nozzle  21 A is increased, ink droplets are discharged from the first nozzle  21 A to the outside. When the ink flows from the first common liquid chamber  101  to the second common liquid chamber  102  through the first individual flow path  200 A, the piezoelectric actuator  300  may be driven, and when the ink does not flow from the first common liquid chamber  101  to the second common liquid chamber  102  through the first individual flow path  200 A, the piezoelectric actuator  300  may be driven. In addition, the ink may temporarily flow from the second common liquid chamber  102  to the first common liquid chamber  101  due to a pressure change induced by driving the piezoelectric actuator  300 . 
     Incidentally, in the embodiment, flow paths of the first individual flow path  200 A which are positioned upstream of the first nozzle  21 A, namely, a portion of the first flow path  201 A which is closer to the second flow path  202 A than the first nozzle  21 A, the second flow path  202 A, the first pressure chamber  12 A, and the first supply path  203 A are referred to as first upstream flow paths. In addition, flow paths of the first individual flow path  200 A which are positioned downstream of the first nozzle  21 A, namely, a portion of the first flow path  201 A which is closer to the fourth flow path  204 A than the first nozzle  21 A, the fourth flow path  204 A, and the fifth flow path  205 A are referred to as first downstream flow paths. 
     As illustrated in  FIG. 12 , the second individual flow path  200 B includes the second nozzle  21 B; the second pressure chamber  12 B; a first flow path  201 B; a second flow path  202 B; a second supply path  203 B; a fourth flow path  204 B; and a fifth flow path  205 B. 
     The second supply path  203 B is a flow path through which the second pressure chamber  12 B communicates with the second common liquid chamber  102 , and penetrates the first communication plate  151  in the Z direction, namely, extends along the Z direction. 
     The second pressure chamber  12 B forms the third flow path that extends in the direction other than the Z direction. The third flow path of the second individual flow path  200 B of the embodiment is formed only of the second pressure chamber  12 B. The second pressure chamber  12 B is, as described above, provided in the flow path formation substrate  10 . In addition, the second pressure chamber  12 B is disposed at a position that is different from the position of the first pressure chamber  12 A of the first individual flow path  200 A in the Y direction. The first pressure chamber  12 A and the second pressure chamber  12 B are provided at positions which do not overlap each other in the plan view from the X direction. Similar to the first pressure chamber  12 A, the second pressure chamber  12 B described above is formed with the first resolution in the X direction. 
     In addition, the second pressure chamber  12 B and the fifth flow path  205 A of the first individual flow path  200 A are disposed at different positions in the Z direction which is the normal direction of the nozzle surface  20   a . Specifically, the second pressure chamber  12 B is provided close to the −Z side with respect to the first communication plate  151 , and the fifth flow path  205 A is provided close to the +Z side with respect to the first communication plate  151 . The second pressure chamber  12 B and the fifth flow path  205 A are disposed at the different positions in the Z direction. For this reason, even though the second pressure chamber  12 B and the fifth flow path  205 A are disposed proximate to each other in the X direction, since the second pressure chamber  12 B and the fifth flow path  205 B are disposed at different positions in the Z direction, the thickness of a partition wall partitioning the second pressure chamber  12 B is prevented from being reduced, and thus it is possible to prevent the occurrence of variations in discharge characteristics, which is caused due to a pressure being absorbed by the deformation of the partition wall of the second pressure chamber  12 B. In addition, even though the second pressure chamber  12 B and the fifth flow path  205 A are disposed such that at least parts of the second pressure chamber  12 B and the fifth flow path  205 A overlap each other in the plan view from the Z direction, the second pressure chamber  12 B and the fifth flow path  205 A do not communicate with each other. 
     Similar to Embodiment 1 described above, the first flow path  201 B extends between the nozzle plate  20  and the communication plate  15  in the Y direction which is the first direction. The first flow path  201 B of the embodiment is formed by providing a recessed portion in the second communication plate  152  and covering an opening of the recessed portion with the nozzle plate  20 . Incidentally, the first flow path  201 B is not specifically limited to being formed by the method, and may be formed by providing a recessed portion in the nozzle plate  20  and covering the recessed portion of the nozzle plate  20  with the second communication plate  152 , or may be formed by providing recessed portions in both of the second communication plate  152  and the nozzle plate  20 , respectively. 
     The first flow path  201 A of the first individual flow path  200 A and the first flow path  201 B of the second individual flow path  200 B are alternately disposed between the communication plate  15  and the nozzle plate  20  in the X direction. A resolution defined by alternately disposing the first flow path  201 A and first flow path  201 B in the X direction is referred to as a second resolution. The second resolution of the first flow path  201 A and the first flow path  201 B is larger than the first resolution of the first pressure chamber  12 A or the second pressure chamber  12 B. For example, if the first pressure chamber  12 A is formed with the first resolution of 300 dpi and the second pressure chamber  12 B is formed with the first resolution of 300 dpi, the first flow path  201 A and the first flow path  201 B are formed with the second resolution of 600 dpi. Therefore, if the first resolution of each of the first pressure chamber  12 A and the second pressure chamber  12 B is set smaller than the second resolution of the first flow path  201 A and the first flow path  201 B, it is possible to widen the opening widths of the first pressure chamber  12 A and the second pressure chamber  12 B in the X direction, and it is possible to increase the excluded volume of the pressure chamber  12 . 
     The second nozzle  21 B is disposed in the middle of the first flow path  201 B described above so as to communicate therewith. In the embodiment, the second nozzle  21 B is disposed at the same position as the position of the first nozzle  21 A in the Y direction, namely, at a position where the first nozzle  21 A and the second nozzle  21 B overlap each other in the plan view from the X direction. 
     In addition, in the embodiment, the first flow path  201 B has a third portion  201   d  having the first cross-sectional area on a side closer to the second flow path  202 B than the second nozzle  21 B, and a fourth portion  201   e  having the second cross-sectional area, which is smaller than the first cross-sectional area, on a side closer to the second common liquid chamber  102  than the second nozzle  21 B. 
     Similar to the second portion  201   b , the fourth portion  201   e  is formed by reducing the height of the third portion  201   d  in the Z direction, specifically, lowering a ceiling of the third portion  201   d  which is opposite to the nozzle  21 . 
     Similar to Embodiment 1 described above, the second flow path  202 B is coupled to the first flow path  201 B, and extends in the second direction, in the embodiment, extends in the Z direction other than the Y direction which is the first direction where the first flow path  201 B extends. The second flow path  202 B is provided to penetrate the communication plate  15  in the Z direction, communicates with the second pressure chamber  12 B at one end in the Z direction, and communicates with the first flow path  201 B at the other end in the Z direction. 
     The fourth flow path  204 B is provided to penetrate the second communication plate  152  in the third direction such that one end of the fourth flow path  204 B communicates with the first flow path  201 B and the other end communicates with the fifth flow path  205 B. Namely, the fourth flow path  204 B extends in the Z direction different from the Y direction which is the first direction where the first flow path  201 B extends. 
     The fifth flow path  205 B extends between the first communication plate  151  and the second communication plate  152  along the Y direction in the in-plane direction of the nozzle surface  20   a  such that one end of the fifth flow path  205 B communicates with the fourth flow path  204 B and the other end communicates with the second common liquid chamber  102 . The fifth flow path  205 B of the embodiment is formed by providing a recessed portion in the second communication plate  152  and covering the recessed portion with the first communication plate  151 . Naturally, the fifth flow path  205 B may be formed by providing a recessed portion in the first communication plate  151  and covering the recessed portion with the second communication plate  152 , or may be formed by providing recessed portions in both of the first communication plate  151  and the second communication plate  152 , respectively. 
     The fifth flow path  205 B of the second individual flow path  200 B described above and the first pressure chamber  12 A of the first individual flow path  200 A are disposed at different positions in the Z direction which is the normal direction of the nozzle surface  20   a . Specifically, the first pressure chamber  12 A is provided close to the −Z side with respect to the first communication plate  151 , and the fifth flow path  205 B is provided close to the +Z side with respect to the first communication plate  151 . The first pressure chamber  12 A and the fifth flow path  205 B are disposed at the different positions in the Z direction. For this reason, even though the first pressure chamber  12 A and the fifth flow path  205 B are disposed proximate to each other in the X direction, since the first pressure chamber  12 A and the fifth flow path  205 B are disposed at different positions in the Z direction, the thickness of a partition wall partitioning the first pressure chamber  12 A is prevented from being reduced, and the partition wall of the first pressure chamber  12 A is prevented from, by being deformed, absorbing the pressure of the ink in the first pressure chamber  12 A, and thus it is possible to prevent the occurrence of variations in discharge characteristics. In addition, even though the first pressure chamber  12 A and the fifth flow path  205 B are disposed such that at least parts of the first pressure chamber  12 A and the fifth flow path  205 B overlap each other in the plan view from the Z direction, since the first pressure chamber  12 A and the fifth flow path  205 B are disposed at the different positions in the Z direction, the first pressure chamber  12 A and the fifth flow path  205 B do not communicate with each other. 
     The second individual flow path  200 B described above has the fifth flow path  205 B, the fourth flow path  204 B, the first flow path  201 B, the second nozzle  21 B, the second flow path  202 B, the second pressure chamber  12 B, and the second supply path  203 B in the order from the upstream region communicating with the first common liquid chamber  101  toward the downstream region communicating with the second common liquid chamber  102 . Namely, in the embodiment, as illustrated in  FIG. 13 , in the second individual flow path  200 B, the second nozzle  21 B and the second pressure chamber  12 B are disposed in the order from the upstream region toward the downstream region with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 . Namely, the order of disposition of the pressure chamber  12  and the nozzle  21  differs between the first individual flow path  200 A and the second individual flow path  200 B with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 . In the embodiment, since each of the individual flow paths  200  is provided with one pressure chamber  12  and one nozzle  21 , the order of disposition of the pressure chamber  12  and the nozzle  21  is reversed between the first individual flow path  200 A and the second individual flow path  200 B. 
     In the second individual flow path  200 B described above, the ink flows from the first common liquid chamber  101  to the second common liquid chamber  102  through the second individual flow path  200 B. In addition, when a change in the pressure of the ink in the second pressure chamber  12 B is induced by driving the piezoelectric actuator  300 , and the internal pressure of the second nozzle  21 B is increased, ink droplets are discharged from the second nozzle  21 B to the outside. When the ink flows from the first common liquid chamber  101  to the second common liquid chamber  102  through the second individual flow path  200 B, the piezoelectric actuator  300  may be driven, and when the ink does not flow from the first common liquid chamber  101  to the second common liquid chamber  102  through the second individual flow path  200 B, the piezoelectric actuator  300  may be driven. In addition, the ink may temporarily flow from the second common liquid chamber  102  to the first common liquid chamber  101  due to a pressure change induced by driving the piezoelectric actuator  300 . By the way, the discharge of ink droplets from the second nozzle  21 B is determined by the pressure of the ink in the second nozzle  21 B. The pressure of the ink in the second nozzle  21 B is determined by the pressure of the ink flowing from the first common liquid chamber  101  toward the second common liquid chamber  102 , namely, a so-called circulation pressure and the pressure of the ink that flows from the second pressure chamber  12 B toward the second nozzle  21 B due to the piezoelectric actuator  300  being driven. 
     For example, with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 , due to a fluctuation in the pressure of the ink in the second pressure chamber  12 B, the ink may flow backward from the second pressure chamber  12 B toward the second nozzle  21 B, and ink droplets may be discharged from the second nozzle  21 B. As described above, the fact that the ink flows backward from the second pressure chamber  12 B toward the second nozzle  21 B implies that the pressure of circulation from the first common liquid chamber  101  toward the second common liquid chamber  102  is low, and thus it is possible to reduce a pressure loss of the individual flow path  200  by reducing the pressure of circulation to a relatively low pressure. If the pressure loss of each of the individual flow paths  200  is reduced, since it is possible to reduce a difference in pressure loss between the individual flow paths  200 , it is possible to reduce variations in the discharge characteristics of ink droplets to be discharged from each of the nozzles  21 . 
     In addition, for example, with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 , due to a fluctuation in the pressure of the ink in the second pressure chamber  12 B, the ink may be discharged from the second nozzle  21 B without the backflow of the ink from the second pressure chamber  12 B toward the second nozzle  21 B. In this case, since the flow of the ink from the second pressure chamber  12 B toward the second nozzle  21 B is not formed, it is difficult for air bubbles to flow backward from the second pressure chamber  12 B toward the second nozzle  21 B, and it is difficult for air bubbles to cause a defect in discharging ink droplets from the second nozzle  21 B. 
     Incidentally, in the embodiment, flow paths of the second individual flow path  200 B which are positioned upstream of the second nozzle  21 B, namely, a portion of the first flow path  201 B which is closer to the fourth flow path  204 B than the second nozzle  21 B, the fourth flow path  204 B, and the fifth flow path  205 B are referred to as second upstream flow paths. In addition, flow paths of the second individual flow path  200 B which are positioned downstream of the second nozzle  21 B, namely, a portion of the first flow path  201 B which is closer to the second flow path  202 B than the second nozzle  21 B, the second flow path  202 B, the second pressure chamber  12 B, and the second supply path  203 B are referred to as second downstream flow paths. 
     The first individual flow path  200 A and the second individual flow path  200 B described above are, as illustrated in  FIG. 13 , alternately provided in the X direction. Namely, regardless of the positions of the pressure chamber  12  and the nozzle  21  with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 , it is possible to discharge ink droplets from the nozzle  21  due to a fluctuation in the internal pressure of the pressure chamber  12 . Namely, even though as in the first individual flow path  200 A, the first pressure chamber  12 A is disposed upstream and the first nozzle  21 A is disposed downstream, and even though as in the second individual flow path  200 B, the second nozzle  21 B is disposed upstream and the second pressure chamber  12 B is disposed downstream, it is possible to selectively discharge ink droplets from both of the first nozzle  21 A and the second nozzle  21 B due to a fluctuation in the pressure of the ink in the pressure chamber  12 . For this reason, as described above, if with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 , the first individual flow path  200 A and the second individual flow path  200 B between which the order of the pressure chamber  12  and the nozzle  21  differs are alternately disposed in the X direction, it is possible to change the position of the pressure chamber  12  between the first individual flow path  200 A and the second individual flow path  200 B, namely, to dispose the first pressure chamber  12 A and the second pressure chamber  12 B at different positions in the Y direction. Therefore, it is possible to form the pressure chamber  12  having a wide width in the X direction in each of the individual flow paths  200 , and it is possible to dispose the pressure chambers  12  at a high density in the X direction. Namely, if the first pressure chamber  12 A and the second pressure chamber  12 B are disposed at the different positions in the Y direction, it is possible to thicken a partition wall between the first pressure chambers  12 A that are arranged side by side in the X direction, and it is possible to thicken a partition wall between the second pressure chambers  12 B that are arranged side by side in the X direction. Therefore, even though each of the first pressure chamber  12 A and the second pressure chamber  12 B is formed having a wide width in the X direction, it is possible to prevent a reduction in the rigidity of the partition wall, it is possible to improve the discharge characteristics of ink droplets, namely, to increase the weight of ink droplets by increasing the excluded volume, and it is possible to prevent the occurrence of cross talk caused by a reduction in the rigidity of the partition wall. In addition, even though the first pressure chambers  12 A and the second pressure chambers  12 B are disposed at a high density in the X direction, it is possible to prevent a reduction in the rigidity of the partition wall, and it is possible to prevent the occurrence of cross talk caused by a reduction in the rigidity of the partition wall. 
     By the way, for example, if the second individual flow path  200 B is not provided and only the first individual flow paths  200 A are arranged side by side in the X direction, when the first pressure chambers  12 A are disposed at a high density in the X direction, the thickness of the partition wall between the first pressure chambers  12 A adjacent to each other is reduced, and the rigidity of the partition wall is reduced. As described above, if the rigidity of the partition wall is reduced, cross talk occurs due to the deformation of the partition wall. Namely, if ink droplets are simultaneously discharged from the nozzles  21  on both sides of the nozzle  21  discharging ink droplets, pressures are applied, at the same timing, from both sides to the partition wall between the first pressure chambers  12 A adjacent to each other. In this case, since pressures are applied from both sides to the partition wall, regardless of the rigidity of the partition wall, it is difficult for the partition wall to be deformed. On the other hand, if ink droplets are not discharged from the nozzles  21  on both sides of the nozzle  21  discharging ink droplets, a pressure is applied only to one side of the partition wall between the first pressure chambers  12 A adjacent to each other. At that time, if the rigidity of the partition wall is low, the partition wall is deformed to absorb a pressure fluctuation, and the discharge characteristics of the ink droplets deteriorate. For this reason, variations in the discharge characteristics of ink droplets occur depending on a difference in condition such as which nozzle discharging ink droplets among the plurality of nozzles  21 . Therefore, if only the first pressure chamber  12 A is provided, it is not possible to form the first pressure chamber  12 A having a wide width in the X direction, and it is not possible to dispose the first pressure chambers  12 A at a high density in the X direction. 
     In the embodiment, since the first pressure chamber  12 A and the second pressure chamber  12 B are disposed at the different positions in the Y direction, it is possible to increase the thickness of the partition wall between the first pressure chambers  12 A, which are adjacent to each other in the X direction, to a relatively large thickness, and it is possible to increase the thickness of the partition wall between the second pressure chambers  12 B, which are adjacent to each other in the X direction, to a relatively large thickness. For this reason, even though each of the first pressure chamber  12 A and the second pressure chamber  12 B is formed having a wide width in the X direction, it is possible to prevent a reduction in the rigidity of the partition wall between the first pressure chambers  12 A and in the rigidity of the partition wall between the second pressure chambers  12 B. Therefore, it is possible to increase the volumes of the first pressure chamber  12 A and the second pressure chamber  12 B by preventing a size increase of the flow path substrate in the X direction, it is possible to improve the discharge characteristics of ink droplets, particularly, to increase the weight of ink droplets by increasing the excluded volume by the drive of the piezoelectric actuator  300 , and it is possible to prevent the occurrence of cross talk caused by a reduction in the rigidity of the partition wall. 
     In addition, even though a gap between the first pressure chamber  12 A and the second pressure chamber  12 B in the X direction is shortened, since it is possible to prevent a reduction in the rigidity of the partition wall between the first pressure chambers  12 A and in the rigidity of the partition wall between the second pressure chambers  12 B, it is possible to dispose the first pressure chambers  12 A and the second pressure chambers  12 B at a high density in the X direction. Therefore, it is possible to attain a size reduction of the flow path substrate in the X direction and to improve the discharge characteristics of ink droplets by increasing the excluded volume of the pressure chamber  12 , it is possible to dispose the pressure chambers  12  at a high density in the X direction and to dispose the nozzles  21  at a high density, and it is possible to prevent the occurrence of cross talk caused by a reduction in the rigidity of the partition wall. 
     In addition, since it is possible to reduce the second resolution of the first flow path  201 A and the first flow path  201 B compared to the first resolution of the first pressure chamber  12 A or the second pressure chamber  12 B, it is possible to dispose the first nozzle  21 A and the second nozzle  21 B close to each other. Namely, since the nozzle  21  is disposed at a position in the middle of each of the first flow path  201 A and the first flow path  201 B, which extend in the in-plane direction of the nozzle surface  20   a , so as to communicate therewith, even though the first pressure chamber  12 A and the second pressure chamber  12 B are disposed at different positions in the Y direction, it is possible to easily adjust the position of the nozzle  21  in the Y direction, and thus it is possible to dispose the plurality of nozzles  21  close to each other in the Y direction, and it is possible to easily dispose the plurality of nozzles  21  in one row on a straight line along the X direction. 
     In the configuration described above, in the plan view from the X direction which is the direction where the nozzles  21  are arranged side by side, in two individual flow paths adjacent to each other in the X direction, namely, in the first individual flow path  200 A and the second individual flow path  200 B, a gap between the nozzle  21 , namely, a gap between the first nozzle  21 A and the second nozzle  21 B is smaller than a gap between the pressure chambers  12 , namely, a gap between the first pressure chamber  12 A and the second pressure chamber  12 B. 
     As described above, if the gap between the first nozzle  21 A and the second nozzle  21 B is made smaller than the gap between the first pressure chamber  12 A and the second pressure chamber  12 B in the Y direction, it is possible to dispose the plurality of nozzles  21  close to each other at a high density, it is possible to dispose the first pressure chamber  12 A and the second pressure chamber  12 B at positions apart from each other in the Y direction, and it is possible to dispose a row of the first pressure chambers  12 A and a row of the second pressure chambers  12 B at a low density compared to the nozzle  21 . Therefore, it is possible to attain a size reduction of the flow path substrate by increasing the excluded volume of each of the pressure chambers  12  or disposing the pressure chambers  12  at a high density. 
     In addition, if the plurality of nozzles  21  are disposed at the same position in the Y direction, it is not necessary to adjust the timing of discharging ink droplets from each of the nozzles  21  so as for the timings to deviate from each other, and it is possible to simplify control of the drive of the piezoelectric actuator  300 . By the way, the reason is that when the recording head  1  moves in the Y direction and discharges ink droplets, if the ink droplets are discharged at the same timing from the nozzles  21  disposed at different positions in the Y direction, since the hitting positions of the ink droplets on an ejection target medium deviate from each other in the Y direction, it is necessary to adjust the drive timing of the piezoelectric actuator  300  so as for the ink droplets to hit the same position in the Y direction. 
     In addition, if the first nozzle  21 A and the second nozzle  21 B are disposed at positions which are relatively apart from each other in the Y direction, turbulent flows generated by ink droplets discharged from the first nozzle  21 A and the second nozzle  21 B influence each other, and there occurs a deviation in the flying direction of the ink droplets, which is a concern. As in the embodiment, if the first nozzle  21 A and the second nozzle  21 B are disposed at relatively close positions, it is possible to prevent turbulent flows from influencing ink droplets discharged from the nozzles  21 , to prevent variations in the flying direction of the ink droplets, and to prevent a deviation in the hitting position of the ink droplets on the ejection target medium. 
     In addition, in the embodiment, the first nozzle  21 A and the second nozzle  21 B are disposed on a straight line along the X direction; however, the present disclosure is not specifically limited to the disposition. For example, if the first nozzle  21 A and the second nozzle  21 B communicate with portions in the middle of the first flow path  201 A and the first flow path  201 B, respectively, the first nozzle  21 A and the second nozzle  21 B may be disposed at deviated positions in the Y direction. 
     As described above, the ink jet type recording head  1  which is one example of the liquid ejecting head of the embodiment includes a flow path substrate which includes the nozzle plate  20  and in which a flow path is formed, and the piezoelectric actuator  300  which is an energy generating element for inducing a change in the pressure of an ink which is a liquid in the flow path. The flow path includes the first common liquid chamber  101 ; the second common liquid chamber  102 ; and the plurality of individual flow paths  200  which communicate with the first common liquid chamber  101  and the second common liquid chamber  102  and through which the ink flows from the first common liquid chamber  101  toward the second common liquid chamber  102 . The individual flow path  200  includes the nozzle  21  that communicates with the outside; the first flow path  201 , in the middle of which the nozzle  21  is disposed and which extends in the Y direction that is the first direction which is the in-plane direction of the nozzle surface  20   a  of the nozzle plate  20  in which the nozzle  21  opens; the second flow path  202  that is coupled to the first flow path  201  and extends in the Z direction which is the second direction other than the Y direction; the third flow path that is coupled to the second flow path  202  and extends in the Y direction which is the third direction other than the Z direction; and the pressure chamber  12  which is disposed in the third flow path and in which a pressure change is induced by the piezoelectric actuator  300 . The first flow path  201  includes the first portion  201   a , which is a portion having the first cross-sectional area, on the side closer to the second flow path  202  than the nozzle  21 , and the second portion  201   b , which is a portion having the second cross-sectional area that is smaller than the first cross-sectional area, on the side that is opposite to the second flow path  202  across the nozzle  21 . 
     As described above, since the nozzle  21  communicates with a portion in the middle of the first flow path  201  extending in the Y direction, the ink flowing through the first flow path  201  enables the ink, which is dried and thickened by the nozzle  21 , to flow to the second common liquid chamber  102  in the downstream region. Therefore, it is possible to dispose the nozzle  21  apart from a portion, for example, the corner between the second flow path  202  and the nozzle plate  20 , in which the ink stays, and the ink thickened by the nozzle  21  is prevented from staying at the corner between the second flow path  202  and the nozzle plate  20 , and thus it is possible to prevent the occurrence of a discharge defect such as the nozzle  21  being clogged by the thickened ink or air bubbles, or a deviation in the flying direction of ink droplets discharged from the nozzle  21 . In addition, air bubbles infiltrating from the nozzle  21  can be prevented from staying at the corner between the second flow path  202  and the nozzle plate  20 , and the air bubbles infiltrating from the nozzle  21  are prevented from moving to the pressure chamber  12 , and thus it is possible to prevent a defect in discharge ink droplets. 
     In addition, since the first portion  201   a  having the first cross-sectional area is provided closer to the second flow path than the nozzle  21 , it is possible to reduce the pressure loss from the pressure chamber  12  to the nozzle  21 , and to prevent a decrease in the weight of ink droplets to be discharged from the nozzle  21 . 
     Furthermore, since the second portion  201   b  having the second cross-sectional area is provided closer to the second common liquid chamber  102  than the nozzle  21 , it is possible to increase the flow speed of the ink flowing the second portion  201   b , the ink thickened by the nozzle  21  or air bubbles infiltrating from the nozzle  21  can be removed by the ink flowing through the second portion  201   b  at a relatively high flow speed, and it is difficult for the thickened ink or the air bubbles to flow backward to the upstream region. 
     In addition, in the recording head  1  of the embodiment, among the individual flow paths  200 , three individual flow paths  200  adjacent to each other in the X direction which is the direction where the nozzles  21  are arranged side by side communicate with the first common liquid chamber  101  and the second common liquid chamber  102 , and the arrangement order of the pressure chamber  12  and the nozzle  21  in the flow direction of the ink as a liquid from the first common liquid chamber  101  toward the second common liquid chamber  102  differs between the first individual flow path  200 A and the second individual flow path  200 B adjacent to each other in the X direction. 
     As described above, if the first individual flow path  200 A and the second individual flow path  200 B, which are individual flow paths  200  between which the arrangement order of the pressure chamber  12  and the nozzle  21  differs, are disposed so as to be adjacent to each other in the X direction, the pressure chambers  12  of the individual flow paths  200  adjacent to each other can be disposed at different positions in the Y direction. Therefore, compared to the case where the individual flow paths  200  between which the order of the pressure chamber  12  and the nozzle  21  is the same are arranged side by side, it is possible to increase the discharge weight of ink droplets by providing the pressure chamber  12  having a wide width in the direction where the nozzles  21  are arranged side by side and increasing the excluded volume of the pressure chamber  12  using the piezoelectric actuator  300 , and it is possible to reduce the size of the flow path substrate by arranging the pressure chambers  12  side by side in the X direction at a high density. In addition, since the pressure chambers  12  of the individual flow paths  200  adjacent to each other can be disposed at deviated positions in the Y direction, the density where the pressure chambers  12  of the individual flow paths  200  adjacent to each other in the X direction are provided is improved, and thus it is possible to dispose the nozzles  21  at a high density. 
     In addition, since the individual flow paths  200  do not merge together at a location in the middle thereof, and the individual flow paths  200  communicate independently with the first common liquid chamber  101  and the second common liquid chamber  102 , it is possible to prevent the occurrence of cross talk which is caused by the influence of a pressure fluctuation between the individual flow paths  200 . Namely, if the individual flow paths  200  merge together before communicating with the first common liquid chamber  101  and the second common liquid chamber  102 , a change in the pressure of the ink in one individual flow path  200  greatly influences the other individual flow path  200 , and there occurs variations in ink discharge characteristics. In the embodiment, since the plurality of individual flow paths  200  communicate only with the first common liquid chamber  101  and the second common liquid chamber  102  which have a relatively large volume, it is possible to reduce the influence of a pressure fluctuation between the plurality of individual flow paths  200 , and it is possible to prevent variations in ink discharge characteristics. 
     Furthermore, since the first common liquid chamber  101  communicate with the second common liquid chamber  102  only through the individual flow path  200 , the ink in the first common liquid chamber  101  does not flow in the X direction which is the direction where the individual flow paths  200  are arranged side by side, a difference in the pressure of the ink to be supplied to the plurality of individual flow paths  200  is unlikely to occur, and variations in the discharge characteristics of the ink discharged from the nozzle  21  are unlikely to occur. By the way, if the ink flows through the first common liquid chamber  101  in the X direction, compared to the pressure of the ink supplied to the individual flow path  200  communicating with an upstream portion of the first common liquid chamber  101 , there occurs a decrease in the pressure of the ink supplied to the individual flow path  200  communicating with a downstream portion, and thus variations in ink discharge characteristics are likely to occur due to variations in the pressure of the ink supplied to the individual flow paths  200 . 
     Incidentally, in the embodiment, preferably, in the individual flow path  200 , the flow path resistance of the downstream flow path closer to the second common liquid chamber  102  than the nozzle  21  is in a range from −50% to +50% with respect to the flow path resistance of the upstream flow path closer to the first common liquid chamber  101  than the nozzle  21 . As described above, if in the individual flow path  200 , the flow path resistance from the nozzle  21  to the second common liquid chamber  102  is set in a range from −50% to +50% with respect to the flow path resistance from the nozzle  21  to the first common liquid chamber  101 , when the first individual flow path  200 A and the second individual flow path  200 B have shapes which are inverted with respect to the ink flow direction from the first common liquid chamber  101  toward the second common liquid chamber  102 , it is easy to equalize the internal pressures of the first nozzle  21 A and the second nozzle  21 B, and thus it is possible to prevent the occurrence of variations in the discharge characteristics of ink droplets. 
     In addition, more preferably, the individual flow path  200  is provided such that the flow path resistance of the upstream flow path closer to the first common liquid chamber  101  than the nozzle  21  is equal to the flow path resistance of the downstream flow path closer to the second common liquid chamber  102  than the nozzle  21 . Accordingly, when the first individual flow path  200 A and the second individual flow path  200 B have shapes which are inverted with respect to the ink flow direction from the first common liquid chamber  101  toward the second common liquid chamber  102 , it is possible to equalize the flow path resistances of the first individual flow path  200 A and the second individual flow path  200 B, and it is possible to further reduce variations in the discharge characteristics of ink droplets. 
     In addition, the flow path resistances of the upstream flow path and the downstream flow path of the individual flow path  200  are not limited to the relationship described above. For example, the flow path resistance may differ between the upstream flow path and the downstream flow path. In the case described above, different voltages may be applied to the piezoelectric actuators  300  of the individual flow paths  200  adjacent to each other in the direction where the nozzles  21  are arranged side by side. 
     For example, if the first individual flow path  200 A and the second individual flow path  200 B have inverted structures, when the flow path resistance of the first upstream flow path is larger than that of the first downstream flow path, the pressure of the ink in the first nozzle  21 A becomes low, and the weight of ink droplets to be discharged from the first nozzle  21 A becomes small. On the other hand, if the first individual flow path  200 A and the second individual flow path  200 B have inverted structures, the flow path resistance of the second upstream flow path is smaller than the flow path resistance of the second downstream flow path, and the pressure of the ink in the second nozzle  21 B becomes low. Therefore, the weight of ink droplets to be discharged from the second nozzle  21 B becomes large. Therefore, a voltage to be applied to the piezoelectric actuator  300  corresponding to the first individual flow path  200 A is made relatively higher than a voltage to be applied to the piezoelectric actuator  300  corresponding to the second individual flow path  200 B. Incidentally, in order to make a voltage to be applied to the piezoelectric actuator  300  corresponding to the first individual flow path  200 A relatively higher than a voltage to be applied to the piezoelectric actuator  300  corresponding to the second individual flow path  200 B, for example, the voltage to be applied to the piezoelectric actuator  300  corresponding to the first individual flow path  200 A may be made high, the voltage to be applied to the piezoelectric actuator  300  corresponding to the second individual flow path  200 B may be made low, or both voltages may be adjusted with respect to a reference voltage. Accordingly, even though there occurs a relatively large difference in internal ink pressure between the first nozzle  21 A and the second nozzle  21 B, it is possible to reduce variations in the weight of ink droplets to be discharged from the first nozzle  21 A and the second nozzle  21 B, and to improve print quality by adjusting a voltage to be applied to the piezoelectric actuator  300 . 
     Other Embodiments 
     The embodiments of the present disclosure are described above; however, basic configurations of the present disclosure are not limited to the configurations described above. 
     For example, in each of the embodiments described above, the communication plate  15  is formed by laminating the first communication plate  151  and the second communication plate  152  on top of each other in the Z direction; however, the present disclosure is not specifically limited to the configuration. The communication plate  15  may be formed of one piece of substrate, or may be formed by laminating three or more pieces of substrates on top of each other. 
     In addition, for example, in each of the embodiments described above, the configuration where one first common liquid chamber  101  and one second common liquid chamber  102  are provided in one flow path substrate is exemplified; however, the present disclosure is not specifically limited to the configuration. 
     Herein, a modification example of the recording head  1  will be described with reference to  FIGS. 14 and 15 . Incidentally,  FIG. 14  is a schematic cross-sectional view describing a flow path configuration which is taken along a line XIV-XIV in  FIG. 10 .  FIG. 15  is a schematic cross-sectional view describing the flow path configuration which is taken along a line XV-XV in  FIG. 10 . 
     As illustrated in  FIGS. 14 and 15 , the first common liquid chamber  101  and the second common liquid chamber  102  are alternately and repeatedly disposed in a flow path substrate  400  in the Y direction. In addition, a plurality of the individual flow paths  200  are provided so as to supply an ink from the first common liquid chamber  101  to the second common liquid chamber  102 . The plurality of individual flow paths  200  are provided along the X direction for one set of one first common liquid chamber  101  and one second common liquid chamber  102 . The individual flow path  200  is positioned between the first common liquid chamber  101  and the second common liquid chamber  102  in the Y direction. 
     The individual flow path  200  has the first individual flow path  200 A having the first nozzle  21 A, and the second individual flow path  200 B having the second nozzle  21 B. 
     As illustrated in  FIG. 14 , the first individual flow path  200 A includes the first nozzle  21 A; the first pressure chamber  12 A; the first flow path  201 A; the second flow path  202 A; and the first supply path  203 A. The first nozzle  21 A is provided in the middle of the first flow path  201 A so as to communicate therewith. 
     The first individual flow path  200 A described above has the first supply path  203 A, the first pressure chamber  12 A, the second flow path  202 A, the first flow path  201 A, and the first nozzle  21 A in the order from an upstream region communicating with the first common liquid chamber  101  toward a downstream region communicating with the second common liquid chamber  102 . Namely, in the embodiment, in the first individual flow path  200 A, the first pressure chamber  12 A and the first nozzle  21 A are disposed in the order from the upstream region toward the downstream region with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 . 
     As illustrated in  FIG. 15 , the second individual flow path  200 B includes the second nozzle  21 B; the second pressure chamber  12 B; the first flow path  201 B; the second flow path  202 B; and the second supply path  203 B. The second nozzle  21 B is provided in the middle of the first flow path  201 B so as to communicate therewith. 
     The second individual flow path  200 B described above has the first flow path  201 B, the second nozzle  21 B, the second flow path  202 B, and the second supply path  203 B in the order from the upstream region communicating with the first common liquid chamber  101  toward the downstream region communicating with the second common liquid chamber  102 . Namely, in the embodiment, in the second individual flow path  200 B, the second nozzle  21 B and the second pressure chamber  12 B are disposed in the order from the upstream region toward the downstream region with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 . Namely, the order of disposition of the pressure chamber  12  and the nozzle  21  differs between the first individual flow path  200 A and the second individual flow path  200 B with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102 . In the embodiment, since each of the individual flow paths  200  is provided with one pressure chamber  12  and one nozzle  21 , the order of disposition of the pressure chamber  12  and the nozzle  21  is reversed between the first individual flow path  200 A and the second individual flow path  200 B. 
     In the embodiment, the first nozzle  21 A and the second nozzle  21 B are arranged side by side on a straight line in the X direction. By the way, the first nozzle  21 A and the second nozzle  21 B may not be arranged side by side on a straight line in the X direction. In addition,  FIGS. 14 and 15  illustrate only two sets of the first common liquid chamber  101  and the second common liquid chamber  102 ; however, three or more sets may be provided in the Y direction, or may be disposed in a so-called matrix pattern. In addition, the flexible cable  120  may be coupled in common to the piezoelectric actuators  300  corresponding to three or more sets of the first common liquid chamber  101  and the second common liquid chamber  102 . 
     In addition,  FIGS. 16 and 17  illustrate a modification example of the recording head  1  in  FIGS. 14 and 15 . Incidentally,  FIG. 16  is a schematic cross-sectional view describing a flow path configuration which is taken along the line XVI-XVI in  FIG. 10 .  FIG. 17  is a schematic cross-sectional view describing the flow path configuration which is taken along the line XVII-XVII in  FIG. 10 . 
     As illustrated in  FIGS. 16 and 17 , the first common liquid chamber  101  and the second common liquid chamber  102  are alternately disposed in the Y direction. 
     In addition, two rows of the individual flow paths  200  deliver the ink from one first common liquid chamber  101  to the second common liquid chambers  102  on both sides in the Y direction. In addition, two rows of the individual flow paths  200  deliver the ink from one second common liquid chamber  102  to the first common liquid chambers  101  on both sides in the Y direction. Namely, one first common liquid chamber  101  communicates with two rows of the individual flow paths  200 , and one second common liquid chamber  102  communicates with two rows of the individual flow paths  200 . As described above, since the first common liquid chamber  101  and the second common liquid chamber  102  are used for both of two rows of the individual flow paths  200 , it is possible to attain a size reduction of the flow path substrate  400  by disposing the nozzles  21  at a high density. 
     In addition, in each of the embodiments described above, the configuration where the individual flow path  200  is provided between the first common liquid chamber  101  and the second common liquid chamber  102  in the Y direction is exemplified; however, the present disclosure is not specifically limited to the configuration. Herein, a modification example of the recording head  1  will be described with reference to  FIGS. 18 to 20 . Incidentally,  FIG. 18  is a schematic cross-sectional view describing a flow path configuration which is taken along the line XVIII-XVIII in  FIG. 10 .  FIG. 19  is a schematic cross-sectional view describing the flow path configuration which is taken along the line XIX-XIX in  FIG. 10 .  FIG. 20  is a diagram schematically illustrating flow paths. 
     As illustrated in  FIGS. 18 and 19 , the first common liquid chamber  101  and the second common liquid chamber  102  are arranged side by side in the Y direction. In addition, the nozzle  21  of the individual flow path  200  which delivers the ink from the first common liquid chamber  101  to the second common liquid chamber  102  is disposed opposite to the first common liquid chamber  101  and the second common liquid chamber  102  in the Y direction. 
     Specifically, the individual flow path  200  includes the first individual flow path  200 A having the first nozzle  21 A, and the second individual flow path  200 B having the second nozzle  21 B. 
     As illustrated in  FIG. 18 , the first individual flow path  200 A includes the first nozzle  21 A; the first pressure chamber  12 A; the first flow path  201 A; the second flow path  202 A; and the first supply path  203 A. 
     The first supply path  203 A extends along the Y direction from the first common liquid chamber  101  toward a side which is opposite to the second common liquid chamber  102  in the Y direction. 
     The first pressure chamber  12 A is disposed in a portion of the flow path substrate  400  which is close to the −Z side. 
     The second flow path  202 A extends along the Z direction, and the first pressure chamber  12 A communicates with the first flow path  201 A through the second flow path  202 A. 
     The first flow path  201 A extends along the Y direction, and the second flow path  202 A communicates with the second common liquid chamber  102  through the first flow path  201 A. 
     Namely, the first individual flow path  200 A extends from the first common liquid chamber  101  toward the side which is opposite to the second common liquid chamber  102  in the Y direction. The first individual flow path  200 A is provided to communicate with the second common liquid chamber  102 . 
     In the first individual flow path  200 A described above, the first pressure chamber  12 A and the first nozzle  21 A are disposed in the order with respect to the ink flow direction from the first common liquid chamber  101  toward the second common liquid chamber  102 . 
     As illustrated in  FIG. 19 , the second individual flow path  200 B includes the second nozzle  21 B; the second pressure chamber  12 B; the first flow path  201 B; the second flow path  202 B; the second supply path  203 B; and the sixth flow path  206 . 
     The second supply path  203 B extends along the Y direction, and the second pressure chamber  12 B communicates with the second common liquid chamber  102  through the second supply path  203 B. 
     The second pressure chamber  12 B is disposed in a portion of the flow path substrate  400  which is close to the −Z side. In addition, the second pressure chamber  12 B is disposed at a position which is different from the position of the first pressure chamber  12 A in the Y direction. 
     The second flow path  202 B extends along the Z direction, and the second pressure chamber  12 B communicates with the first flow path  201 B through the second flow path  202 B. 
     The first flow path  201 B extends along the Y direction, and the second flow path  202 B communicates with the sixth flow path  206  through the first flow path  201 B. 
     The sixth flow path  206  extends along the Z direction, and the first flow path  201 B communicates with the first common liquid chamber  101  through the sixth flow path  206 . 
     Namely, the second individual flow path  200 B extends from the first common liquid chamber  101  toward the side which is opposite to the second common liquid chamber  102  in the Y direction. The second individual flow path  200 B is provided to communicate with the second common liquid chamber  102 . 
     In the second individual flow path  200 B described above, the second nozzle  21 B and the second pressure chamber  12 B are disposed in the order with respect to the ink flow direction from the first common liquid chamber  101  toward the second common liquid chamber  102 . Namely, as illustrated in  FIG. 20 , the order of disposition of the pressure chamber  12  and the nozzle  21  with respect to the flow of the ink from the first common liquid chamber  101  toward the second common liquid chamber  102  differs between the first individual flow path  200 A and the second individual flow path  200 B. In the embodiment, since each of the individual flow paths  200  is provided with one pressure chamber  12  and one nozzle  21 , the order of disposition of the pressure chamber  12  and the nozzle  21  is reversed between the first individual flow path  200 A and the second individual flow path  200 B. 
     In the configuration described above, since the order of the pressure chamber  12  and the nozzle  21  differs between the first individual flow path  200 A and the second individual flow path  200 B, it is possible to dispose the first pressure chamber  12 A and the second pressure chamber  12 B at different positions in the Y direction, and it is possible to increase the excluded volume, or to dispose the pressure chambers  12  at a high density by widening the width of the pressure chamber  12  in the X direction which is the direction where the nozzles  21  are arranged side by side. 
     In addition, in the recording head  1  illustrated in  FIGS. 18 and 19 , the first nozzle  21 A and the second nozzle  21 B are disposed on one side in the Y direction with respect to the first common liquid chamber  101  and the second common liquid chamber  102 , but may be disposed on both sides. Namely, the individual flow path  200  may be provided on both sides in the Y direction with respect to one first common liquid chamber  101 , and the individual flow path  200  may be provided on both sides in the Y direction with respect to one second common liquid chamber  102 . 
     In addition, since the first nozzle  21 A and the second nozzle  21 B communicate with portions in the middle of the first flow path  201 A and the first flow path  201 B, respectively, the ink thickened by the first nozzle  21 A and the second nozzle  21 B or infiltrated air bubbles are capable of flowing downstream by virtue of the ink flowing through the first flow path  201 A and the first flow path  201 B at a high flow speed. Therefore, it is possible to prevent the occurrence of a discharge defect caused by the thickened ink or air bubbles. 
     Incidentally, compared to the configuration described above where the nozzle  21  is not provided between the first common liquid chamber  101  and the second common liquid chamber  102  in the plan view from the Z direction which is the normal direction of the nozzle surface  20   a  as illustrated in  FIGS. 18 and 19 , as in each of the embodiments described above, in the configuration where the nozzle  21  is provided between the first common liquid chamber  101  and the second common liquid chamber  102  in the plan view from the Z direction, it is possible to simplify the configuration of the individual flow path  200 , and it is possible to prevent the multi-layering of the communication plate  15 . 
     In addition, in each of the embodiments described above, the configuration where one nozzle  21  and one pressure chamber  12  are provided for each of the individual flow paths  200  is exemplified, but the number of the nozzles  21  and the number of the pressure chambers  12  are not specifically limited. Two or more plurality of the nozzles  21  may be provided for one pressure chamber  12 , and two or more plurality of the pressure chambers  12  may be provided for one nozzle  21 . However, ink droplets are simultaneously discharged in one discharge period from the nozzles  21  provided in one individual flow path  200 . Namely, even though the plurality of nozzles  21  are provided in one individual flow path  200 , only either of a discharge mode in which ink droplets are simultaneously discharged from the plurality of nozzles  21  and a non-discharge mode in which ink droplets are not simultaneously discharged therefrom is performed. Namely, in the configuration where the plurality of nozzles  21  are provided in one individual flow path  200 , the discharge mode in which ink droplets are discharged from the plurality of nozzles  21  and the non-discharge mode in which ink droplets are not discharged therefrom may not be simultaneously performed. 
     In addition, in each of the embodiments described above, the flow path substrate has the flow path formation substrate  10 , the communication plate  15 , the nozzle plate  20 , the compliance substrate  49 , the case member  40 , and the like; however, the present disclosure is not specifically limited to the configuration. The flow path substrate may be one piece of substrate, or may be formed by laminating two or more plurality of pieces of substrates on top of each other. For example, the flow path substrate may include the flow path formation substrate  10  and the nozzle plate  20 , and may not include the communication plate  15 , the compliance substrate  49 , and the case member  40 . In addition, one pressure chamber  12  may be formed by a plurality of the flow path formation substrates  10 , and the pressure chamber  12 , the first common liquid chamber  101 , and the second common liquid chamber  102  may be formed in the flow path formation substrate  10 . 
     In addition, in each of the embodiments described above, the piezoelectric actuator  300  which is a thin film type is described as an energy generating element that induces a pressure change in the pressure chamber  12 ; however, the present disclosure is not specifically limited to the type. It is possible to use, for example, a thick film type piezoelectric actuator formed by a method such as pasting green sheets together, or a longitudinal vibration type piezoelectric actuator in which a piezoelectric material and an electrode forming material are alternately laminated on top of each other and which expands and contracts in an axial direction. In addition, as an energy generating element, it is possible to use, for example, an actuator in which a heating element is disposed in a pressure chamber and discharges liquid droplets from a nozzle by means of bubbles formed by heat of the heating element, or a so-called electrostatic actuator that discharges liquid droplets from a nozzle opening by generating static electricity between a vibrating plate and an electrode, and deforming the vibrating plate with the static electricity. 
     Herein, one example of an ink jet type recording apparatus which is one example of a liquid ejecting apparatus of the embodiment will be described with reference to  FIG. 21 . Incidentally,  FIG. 21  is a view illustrating a schematic configuration of the ink jet type recording apparatus of the present disclosure. 
     As illustrated in  FIG. 21 , in an ink jet type recording apparatus I which is one example of the liquid ejecting apparatus, a plurality of the recording heads  1  are mounted on a carriage  3 . The carriage  3  on which the recording heads  1  are mounted are provided on a carriage shaft  5  attached to an apparatus main body  4 , so as to be movable in an axial direction. In the embodiment, a movement direction of the carriage  3  is the Y direction. 
     In addition, the apparatus main body  4  is provided with a tank  2  which is a storage unit that stores an ink as a liquid. The tank  2  is coupled to the recording heads  1  via a supply pipe  2   a  such as a tube, and the ink from the tank  2  is supplied to the recording heads  1  via the supply pipe  2   a . In addition, the recording heads  1  are coupled to the tank  2  via an outlet pipe  2   b  such as a tube, and the ink flowing out from the recording heads  1  returns to the tank  2  via the outlet pipe  2   b , namely, so-called circulation is performed. Incidentally, a plurality of the tanks  2  may be provided. 
     If a drive force of a drive motor  7  is transmitted to the carriage  3  via a plurality of gears (not illustrated) and a timing belt  7   a , the carriage  3  on which the recording heads  1  are mounted move along the carriage shaft  5 . On the one hand, a transport roller  8  as a transport unit is provided in the apparatus main body  4 , and a recorded sheet S such as paper which is an ejection target medium is transported by the transport roller  8 . Incidentally, the transport unit which transports the recorded sheet S is not limited to the transport roller  8 , and may be a belt, a drum, or the like. In the embodiment, a transport direction of the recorded sheet S is the X direction. 
     Incidentally, in the ink jet type recording apparatus I described above, a configuration where the recording heads  1  are mounted on the carriage  3  and move in a main scanning direction is exemplified; however, the present disclosure is not specifically limited to the configuration. The present disclosure can be applied, for example, also to a so-called line type recording apparatus that performs printing only by moving the recorded sheet S such as paper in an auxiliary scanning direction in a state where the recording heads  1  are fixed. 
     Incidentally, in each of the embodiments, the ink jet type recording head and the ink jet type recording apparatus are exemplarily described as one example of the liquid ejecting head and one example of the liquid ejecting apparatus, respectively. The present disclosure is intended for a wide range of liquid ejecting heads and liquid ejecting apparatuses in general, and naturally, can be applied also to liquid ejecting heads or liquid ejecting apparatuses which eject liquids other than an ink. Examples of other liquid ejecting heads include various recording heads used in image recording apparatuses such as a printer, a color material ejecting head used to manufacture color filters such as a liquid crystal display, an electrode material ejecting head used to form electrodes such as an organic EL display and a field emission display (FED), a bioorganic matter ejecting head used to manufacture biochips. The present disclosure can be applied also to liquid ejecting apparatuses including the liquid ejecting heads. 
     Herein, one example of a liquid circulation system of the embodiment will be described with reference to  FIG. 22 . Incidentally,  FIG. 22  is a block diagram describing the liquid circulation system of the ink jet type recording apparatus which is the liquid ejecting apparatus of the present disclosure. 
     As illustrated in  FIG. 22 , the liquid circulation system includes a main tank  500 ; the recording head  1  of each of the embodiments described above; a first tank  501 ; a second tank  502 ; a compressor  503 ; a vacuum pump  504 ; a first liquid delivery pump  505 ; and a second liquid delivery pump  506 . 
     The recording head  1  and the compressor  503  are coupled to the first tank  501 , and the ink in the first tank  501  is supplied to the recording head  1  at a predetermined positive pressure by the compressor  503 . 
     The second tank  502  is coupled to the first tank  501  via the first liquid delivery pump  505 , and the ink in the second tank  502  is delivered to the first tank  501  by the first liquid delivery pump  505 . 
     In addition, the recording head  1  and the vacuum pump  504  are coupled to the second tank  502 , and the ink in the recording head  1  flows out to the second tank  502  at a predetermined negative pressure due to the vacuum pump  504 . 
     Namely, the ink is supplied from the first tank  501  to the recording head  1 , and the ink flows out from the recording head  1  to the second tank  502 . The ink is delivered from the second tank  502  to the first tank  501  by the first liquid delivery pump  505 . As a result, the circulation of the ink is completed. 
     In addition, the main tank  500  is coupled to the second tank  502  via the second liquid delivery pump  506 , and a volume of the ink which is as much as consumed by the recording head  1  is replenished from the main tank  500  to the second tank  502 . Incidentally, the ink may be replenished from the main tank  500  to the second tank  502  at a timing, for example, when the liquid level of the ink in the second tank  502  becomes lower than a predetermined height.