Patent Publication Number: US-2023139118-A1

Title: Liquid Ejecting Head And Liquid Ejecting Apparatus

Description:
The present application is based on, and claims priority from JP Application Serial Number 2021-176204, filed Oct. 28, 2021, 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 that eject liquid from a nozzle, and particularly to an ink jet type recording head and an ink jet type recording apparatus that eject ink as liquid. 
     2. Related Art 
     The liquid ejecting head is provided with a pressure adjustment unit that opens and closes a flow path to adjust a supply pressure of the liquid in the middle of the flow path for supplying the liquid from a storage unit in which the liquid is stored (for example, see JP-A-2019-51614 and JP-A-2009-83471). 
     The pressure adjustment unit opens and closes the flow path by forming a part of the flow path by a diaphragm, making a pressure of the liquid in the flow path negative with respect to an atmospheric pressure, deforming the diaphragm in accordance with a differential pressure between the pressure of the liquid in the flow path and the atmospheric pressure outside the diaphragm, and moving a valve body by the diaphragm. 
     In the liquid ejecting head having the pressure adjustment unit as in JP-A-2019-51614, in some cases, it is necessary to forcibly open the flow path in the pressure adjustment unit. Examples of when it is necessary to forcibly open the flow path in the pressure adjustment unit include a time of pressurization cleaning in which the liquid is discharged from the nozzle by pressurizing the liquid from upstream of the pressure adjustment unit, and a time of initial filling in which the liquid is supplied to the liquid ejecting head by pressurizing the liquid from upstream of the pressure adjustment unit. In addition, another example thereof includes a time of a printing inspection in which a valve function of the pressure adjustment unit is invalidated and the liquid is ejected from the liquid ejecting head to confirm a printing state to confirm a liquid ejection characteristic. 
     However, when the pressure adjustment unit is disposed in a housing of the liquid ejecting head as in JP-A-2009-83471, in order to forcibly open the flow path blocked by the valve body, it is necessary to dispose a mechanism that presses a flexible film of the pressure adjustment unit by pressurizing and supplying air, or a mechanism that mechanically presses a flexible film of the pressure adjustment unit using an eccentric cam or a drive rod in the housing of the liquid ejecting head. There is a problem that a size of the liquid ejecting head is increased in order to secure a space for disposing such a mechanism in the housing of the liquid ejecting head. 
     SUMMARY 
     According to an aspect of the present disclosure, there is provided a liquid ejecting head including a liquid ejecting section that ejects liquid, a first valve unit that adjusts a pressure of the liquid to be supplied to the liquid ejecting section, and a housing that accommodates the liquid ejecting section and the first valve unit, in which the first valve unit includes a first flow path that communicates with the liquid ejecting section, a first flexible film that has a first inner surface defining a part of the first flow path and a first outer surface being opposite to the first inner surface and being in contact with an atmosphere, and is displaceable in a first direction from the first outer surface toward the first inner surface and in a second direction opposite to the first direction, and a first valve body that is moved between an opening position at which the first flow path is opened and a closing position at which the first flow path is closed, due to displacement of the first flexible film, and the housing has a first opening portion that is formed at a position facing at least a part of the first outer surface. 
     In addition, according to another aspect of the present disclosure, there is provided a liquid ejecting apparatus including the liquid ejecting head according to the aspect described above, and a liquid storage section that stores the liquid to be supplied to the liquid ejecting head. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic view of a liquid ejecting apparatus. 
         FIG.  2    is a schematic view of a main section of the liquid ejecting apparatus. 
         FIG.  3    is an exploded perspective view of a supply member and a head unit. 
         FIG.  4    is a plan view of the head unit. 
         FIG.  5    is a perspective view of a recording head. 
         FIG.  6    is an exploded perspective view of the recording head. 
         FIG.  7    is an exploded perspective view of the recording head. 
         FIG.  8    is a plan view of the recording head. 
         FIG.  9    is a cross-sectional view of the recording head. 
         FIG.  10    is a cross-sectional view of the recording head. 
         FIG.  11    is a side view of a valve unit. 
         FIG.  12    is a cross-sectional view of the valve unit. 
         FIG.  13    is a cross-sectional view of the valve unit. 
         FIG.  14    is a cross-sectional view of the recording head and a pressing mechanism. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     In the following, the present disclosure will be described in detail based on the embodiments. It should be noted that the following description shows one aspect of the present disclosure, and can be optionally changed within the scope of the present disclosure. The components having the same reference numerals in the figures indicate the same members, and the description thereof will be omitted as appropriate. Also, X, Y, and Z in each figure indicate three spatial axes that are orthogonal to each other. In the present specification, the directions along these spatial axes are referred to as an X direction, a Y direction, and a Z direction. In the description, a direction in which an arrow in each figure is directed is referred to as a positive (+) direction, and an opposite direction of the arrow is referred to as a negative (−) direction. In addition, the three spatial axes that do not limit the positive direction and the negative direction will be described as an X axis, a Y axis, and a Z axis. 
     First Embodiment 
       FIG.  1    is a schematic view showing a schematic configuration of a liquid ejecting apparatus according to a first embodiment of the present disclosure as viewed in the +Z direction.  FIG.  2    is a schematic view of an ink jet type recording apparatus, which is the liquid ejecting apparatus, as viewed in the +X direction. 
     As shown in  FIGS.  1  and  2   , an ink jet type recording apparatus I, which is an example of the “liquid ejecting apparatus” according to the present embodiment is a printing apparatus that ejects and impacts ink, which is a type of liquid, on a medium S, such as printing paper, to perform printing of an image or the like (also referred to as a recording operation) by arranging dots formed on the medium S. It should be noted that, any material, such as a resin film or cloth, can be used as the medium S in addition to the printing paper. In addition, the ink jet type recording apparatus I according to the present embodiment is a so-called line-type recording apparatus that performs printing by ejecting and impacting the ink from an ink jet type recording head  10  to the medium S while transporting the medium S in a state being fixed to the ink jet type recording head  10  during printing. 
     The ink jet type recording apparatus I includes a head unit  1  including the ink jet type recording head  10  (hereinafter, also simply referred to as a recording head  10 ), which is an example of a “liquid ejecting head”, a supply member  2  that supplies the ink to the head unit  1 , a liquid storage section  4  that stores the ink, an apparatus main body  7 , and a control unit  8 . 
     The head unit  1  has a plurality of recording heads  10  capable of ejecting the ink from a nozzle  21  (see  FIG.  7   ). The plurality of recording heads  10  are arranged side by side in a direction intersecting the +Y direction, which is a transport direction of the medium S, that is, a direction along the X axis in the present embodiment. It should be noted that the details of the head unit  1  will be described later. In addition, although the head unit  1  according to the present embodiment has the plurality of recording heads  10 , the number of the recording heads  10  constituting the head unit  1  is not particularly limited, and the head unit  1  may include one recording head  10 . The supply member  2  is fixed to such a head unit  1 . The ink supplied from the supply member  2  is supplied to each recording head  10  constituting the head unit  1 . 
     The liquid storage section  4  stores the ink to be supplied to the recording head  10 . The ink stored in the liquid storage section  4  is the ink that contributes to printing, that is, the ink that is ejected as droplets from the nozzle  21  of the recording head  10  in order to form an image or the like on the medium S. Examples of the liquid storage section  4  include a cartridge that can be attached to and detached from the ink jet type recording apparatus I, a bag-shaped ink pack made of a flexible film, and a tank that can be refilled with the liquid. In the present embodiment, such a liquid storage section  4  is fixed to the apparatus main body  7 . It should be noted that, although not particularly shown, a plurality of types of ink having different colors or types are individually stored in the liquid storage section  4 . In addition, a sub tank may be provided between the liquid storage section  4  and the head unit  1 . When the ink in the sub tank is reduced, the reduced amount of the ink may be replenished from the liquid storage section  4  to the sub tank. 
     The ink from the liquid storage section  4  is supplied to each recording head  10  of the head unit  1  via a supply pipe  4   a,  such as a tube. In addition, in the middle of the supply pipe  4   a,  a pump  4   b,  which is a pressurizing mechanism that pressurizes and supplies the ink from the liquid storage section  4  toward the recording head  10 , is provided. It should be noted that the pressurizing mechanism is not limited to the pump  4   b,  and may be a pressing mechanism or the like that presses the liquid storage section  4  from the outside. In addition, the pressurizing mechanism may use a water head differential pressure generated by adjusting a relative position in a vertical direction between the recording head  10  and the liquid storage section  4 . It should be noted that, in the present embodiment, the liquid storage section  4  is fixed to the apparatus main body  7 , but for example, a liquid storage section, such as an ink cartridge, may be mounted on the supply member  2 , that is, on the −Z direction side of the supply member  2 . 
     In addition, the ink jet type recording apparatus I may include a transport unit. A first transport unit  5  as an example of the transport unit is provided on the −Y direction side of the ink jet type recording apparatus I. The first transport unit  5  includes a first transport roller  501  and a first driven roller  502  that is driven by the first transport roller  501 . The first transport roller  501  is provided on a back surface side opposite to an impact surface on which the ink of the medium S is impacted, and is driven by a driving force of a first drive motor  503 . In addition, the first driven roller  502  is provided on the impact surface side on which the ink of the medium S is impacted, and interposes the medium S with the first transport roller  501 . Such a first driven roller  502  presses the medium S toward the first transport roller  501  side by an urging member, such as a spring (not shown). 
     In addition, a second transport unit  6  as an example of the transport unit is disposed in the +Y direction downstream of the transport direction of the medium S with respect to the first transport unit  5 , and includes a transport belt  601 , a second drive motor  602 , a second transport roller  603 , a second driven roller  604 , and a tension roller  605 . The second transport roller  603  is driven by the driving force of the second drive motor  602 . The transport belt  601  is formed by an endless belt, and is hung on outer circumferences of the second transport roller  603  and the second driven roller  604 . Such a transport belt  601  is provided on the back surface side of the medium S. The tension roller  605  is provided between the second transport roller  603  and the second driven roller  604 , abuts on an inner circumferential surface of the transport belt  601 , and applies tension to the transport belt  601  by an urging force of the urging member  606 , such as a spring. As a result, the transport belt  601  has a flat surface that faces the recording head  10  between the second transport roller  603  and the second driven roller  604 . 
     The control unit  8  is a controller according to the present embodiment, and although not particularly shown, for example, includes a control device, such as a central processing unit (CPU) or a field programmable gate array (FPGA), and a storage device, such as a semiconductor memory. In the control unit  8 , each element of the ink jet type recording apparatus I, that is, the recording head  10 , the first transport unit  5 , the second transport unit  6 , the pump  4   b,  and the like are comprehensively controlled by the control device executing a program stored in the storage device. That is, the control unit  8  controls the recording operation and the like. In addition, the control unit  8  controls a pressing mechanism  80  (see  FIG.  14   ) that forcibly opens a valve unit  60 , which will be described later in detail, to open a valve unit flow path  64 . 
     In such an ink jet type recording apparatus I, printing is performed by ejecting the ink from the recording head  10  in the +Z direction while transporting the medium S by the first transport unit  5  and the second transport unit  6  in the +Y direction with respect to the head unit  1 , and impacting the ejected ink in the medium S. The transport unit is not limited to the first transport unit  5  and the second transport unit  6  described above, and a transport unit including a drum or the like may be used. 
     The head unit  1  will be described with reference to  FIGS.  3  to  10   . It should be noted that  FIG.  3    is an exploded perspective view of the supply member  2  and the head unit  1 .  FIG.  4    is a plan view of the head unit  1  as viewed in the +Z direction.  FIG.  5    is a perspective view of the recording head  10 .  FIGS.  6  and  7    are exploded perspective views of the recording head  10 .  FIG.  8    is a plan view of the recording head  10  as viewed in the −Z direction.  FIG.  9    is a cross-sectional view taken along the line IX-IX of  FIG.  8   .  FIG.  10    is a cross-sectional view taken along the line X-X of  FIG.  9   . 
     As shown in  FIGS.  3  and  4   , the head unit  1  includes the plurality of recording heads  10  and a support  3  that supports the plurality of recording heads  10 . 
     The support  3  is formed of a plate-shaped member, and is provided with support holes  3   a  for holding a plurality of recording heads  10 . In the present embodiment, the support holes  3   a  are provided independently for each recording head  10 . Of course, the support holes  3   a  may be continuously provided over the plurality of recording heads  10 . 
     An ejection surface of the recording head  10  is held in the support hole  3   a  of the support  3  in a state of protruding from the +Z direction side of the support  3 . It should be noted that, in the present embodiment, the surface of the recording head  10  facing the medium S is referred to as the ejection surface. 
     As shown in  FIG.  4   , there are the plurality of recording heads  10  held by such a support  3  along the X axis, in the present embodiment, two rows each having three recording heads  10  arranged side by side are provided along the Y axis. That is, six recording heads  10  are held on one support  3 . 
     Each recording head  10  is provided with fixing holes  11  at both end portions in the +X direction and the −X direction. The support  3  is provided with a screw hole  3   b  for fixing each recording head  10 , and a screw  12  is inserted into the fixing hole  11  and screwed into the screw hole  3   b,  so that each recording head  10  is fixed to the support  3 . 
     Here, as shown in  FIGS.  5  to  10   , the recording head  10  includes a plurality of liquid ejecting sections  20  having the nozzles  21  that eject the ink, a holder  30  that holds the plurality of liquid ejecting sections  20 , a fixing plate  40  that fixes the plurality of liquid ejecting sections  20 , a flow path member  50  that supplies the ink to the liquid ejecting section  20 , a valve unit  60  that supplies the ink to the flow path member  50 , and a cover  70  that accommodates the valve unit. 
     As shown in  FIG.  8   , the nozzles  21  that eject the ink are arranged side by side along the X axis in the liquid ejecting section  20 . In addition, the liquid ejecting section  20  is provided with, along the Y axis, a plurality of rows of the nozzles  21  arranged side by side along the X axis, and two rows in the present embodiment. 
     A flow path that communicates with the nozzle  21  and a pressure generation unit that causes a pressure change in the ink in the flow path are provided in an inside (not shown) of the liquid ejecting section  20 . As the pressure generation unit, for example, a unit that changes a volume of the flow path by the deformation of a piezoelectric actuator having a piezoelectric material exhibiting an electromechanical conversion function, causing the pressure change in the ink in the flow path, and ejects the ink droplets from the nozzle  21  can be used. In addition, as other pressure generation unit, a unit in which a heat generation element is disposed in the flow path to eject the ink droplets from the nozzle  21  by bubbles generated due to the heat of the heat generation element, or a so-called electrostatic actuator that generates an electrostatic force between a vibration plate and an electrode, deforms the vibration plate by the electrostatic force, and ejects the ink droplets from the nozzle  21  can be used. It should be noted that the surface of the liquid ejecting section  20  on which the nozzle  21  is open is a nozzle surface. That is, the ejection surface of the head unit  1  includes the nozzle surface on which the nozzle  21  is formed. 
     In addition, a wiring substrate  22  coupled to an internal pressure generation unit (not shown) is derived from the surface of the liquid ejecting section  20  on the −Z direction side. As the wiring substrate  22 , a flexible sheet-like material, for example, a so-called flexible substrate, such as a COF substrate, can be used. In addition, for example, on the wiring substrate  22 , a switching element that drives the pressure generation unit may or may not be mounted. That is, the wiring substrate  22  may be flexible wiring, such as FFC or FPC. 
     As shown in  FIGS.  7 ,  8 , and  9   , the holder  30  holds the plurality of liquid ejecting sections  20 . Specifically, an accommodation section  31  is provided on the surface of the holder  30  in the +Z direction. The accommodation section  31  has a recessed shape that is open on the surface in the +Z direction, and accommodates a plurality of liquid ejecting sections  20  fixed by the fixing plate  40 . In addition, an opening of the accommodation section  31  is covered with the fixing plate  40 . That is, the liquid ejecting section  20  is accommodated inside a space constituted by the accommodation section  31  and the fixing plate  40 . The accommodation section  31  is independently provided for each liquid ejecting section  20 . Of course, the accommodation section  31  may be continuously provided over the plurality of liquid ejecting sections  20 . In addition, the surface of the liquid ejecting section  20  on the −Z direction side is adhered to a bottom portion of the accommodation section  31 , that is, the surface of an inner surface of the accommodation section  31  on the −Z direction side with an adhesive. 
     In such a holder  30 , the liquid ejecting sections  20  are disposed in a staggered manner along the X axis. Here, disposing the liquid ejecting sections  20  in a staggered manner along the X axis means that the liquid ejecting sections  20  arranged side by side along the X axis are disposed to be alternately displaced from the Y axis. That is, two rows of the liquid ejecting sections  20  arranged side by side along the X axis are arranged side by side along the Y axis, and two rows of the liquid ejecting sections  20  are disposed to deviate by half a pitch along the X axis. By disposing the liquid ejecting sections  20  in a staggered manner along the X axis in this way, the nozzles  21  of two liquid ejecting sections  20  can be partially overlapped along the X axis to form a continuous row of the nozzles  21  in the direction along the X axis. 
     In addition, a recess portion  33  having a recessed shape in which the fixing plate  40  is fixed is provided on the surface of the holder  30  on the +Z direction side on which the accommodation section  31  is provided. The recess portion  33  has an opening of a size and a shape in which the fixing plate  40  is fitted and fixed. The fixing plate  40  is constituted by a plate-shaped member, and is fixed in the recess portion  33  of the holder  30  with an adhesive or the like. The fixing plate  40  is provided with an exposure opening portion  41  that exposes the nozzle  21  of each liquid ejecting section  20 . In the present embodiment, the exposure opening portion  41  is provided independently for each liquid ejecting section  20 . It should be noted that a periphery portion of the exposure opening portion  41  of the fixing plate  40  is fixed to the nozzle  21  side of the liquid ejecting section  20 , that is, the surface on the +Z direction side with an adhesive or the like. The surface of the fixing plate  40  in the +Z direction constitutes a part of the ejection surface. 
     In addition, inside the holder  30 , a flow path for flowing the ink may be provided between the liquid ejecting section  20  and the flow path member  50 . Of course, a flow path of the flow path member  50  and a flow path of the liquid ejecting section  20  may directly communicate with each other without passing through the holder  30 . 
     In addition, the holder  30  is provided with a wiring insertion hole  34  into which the wiring substrate  22  of the liquid ejecting section  20  is inserted. The wiring insertion hole  34  is provided to be open on a bottom surface of the accommodation section  31 , that is, on the surface of the accommodation section  31  on the −Z direction side, and also to be open on the surface of the holder  30  on the −Z direction side. 
     A pair of flange portions  35  protruding in the +X direction and the −X direction, respectively, are provided on the −Z direction side of the holder  30 . The fixing hole  11  into which the screw  12  described above is inserted is provided to penetrate the flange portion  35  in the +Z direction. 
     Here, a shape of the recording head  10  in a plan view as viewed in the −Z direction will be described with reference to  FIG.  8   . The recording head  10  includes a first portion P 1  (portion shown by hatching in  FIG.  8   ), a second portion P 2 , and a third portion P 3 . 
     When a rectangle having the minimum area including the recording head  10  is denoted by R, a long side E 1  of the rectangle R overlaps with a side along the +X direction of the holder  30 , and a short side E 2  of the rectangle R overlaps with a side along the +Y direction of the holder  30 . A center line parallel to the long side E 1  of such an imaginary rectangle R is denoted by LC. 
     The first portion P 1  is a rectangular portion through which the center line LC passes. The second portion P 2  is a rectangular portion protruding from the first portion P 1  in the −X direction. The third portion P 3  is a rectangular portion protruding from the first portion P 1  in the +X direction. That is, the second portion P 2 , the first portion P 1 , and the third portion P 3  are arranged in this order along the X axis in the +X direction. 
     The second portion P 2  and the third portion P 3  are positioned in opposite directions along the Y axis with the center line LC interposed therebetween. Moreover, the plurality of recording heads  10  are arranged along the X axis such that the second portion P 2  of one recording head  10  and the third portion P 3  of the other recording head  10  face each other in the direction of the Y axis. In this way, by disposing the second portion P 2  of one recording head  10  and the third portion P 3  of the other recording head  10  to face each other in the direction of the Y axis, the nozzles  21  of the recording heads  10  adjacent to each other along the X axis can be partially overlapped along the X axis to form a continuous row of the nozzles  21  over the X axis. It should be noted that the second portion P 2  and the third portion P 3  have a width along the Y axis that does not pass through the center line LC. Therefore, when the plurality of recording heads  10  are arranged along the X axis, the width in the direction along the Y axis occupied by the plurality of recording heads  10  is further narrowed, and the size of the head unit  1  can be reduced in the direction along the Y axis. 
     As shown in  FIGS.  5  to  10   , the flow path member  50  is fixed to the surface of the holder  30  on the −Z direction side. A flow path for supplying the ink to the liquid ejecting section  20  is provided inside the flow path member  50  (not shown), and the ink supplied from the liquid storage section  4  is supplied to the flow path member  50  via the valve unit  60  and is supplied from the flow path member  50  to each liquid ejecting section  20 . It should be noted that the flow path provided inside the flow path member  50  may be branched. In addition, a filter or the like for removing foreign substances, such as air bubbles, contained in the ink may be provided in the middle of the flow path of the flow path member  50 . 
     In addition, the valve unit  60  and the cover  70  are provided on the surface of the flow path member  50  in the −Z direction. A plurality of valve units  60  are provided in accordance with the number of the liquid ejecting sections  20 . That is, in the present embodiment, since one recording head  10  is provided with four liquid ejecting sections  20 , four valve units  60  are also provided in accordance with the number of the liquid ejecting sections  20 . It should be noted that the number of the valve units  60  and the number of the liquid ejecting sections  20  do not necessarily have to match. Similar to the liquid ejecting section  20 , four valve units  60  are provided with two rows each having two valve units  60  arranged side by side along the X axis on the Y axis. Two rows of the liquid ejecting sections  20  provided on the Y axis are disposed at positions deviating from each other along the X axis. In the present embodiment, among the four valve units  60 , in the recording head  10 , the valve unit  60  positioned relatively in the −X direction and the −Y direction is referred to as a first valve unit  60 A, and the valve unit  60  positioned on the −X direction and the +Y direction side is referred to as a second valve unit  60 B. In addition, in the recording head  10 , among the four valve units  60 , the valve unit  60  positioned relatively in the +X direction and the −Y direction is referred to as a third valve unit  60 C, and the valve unit  60  positioned on the +X direction and the +Y direction side is referred to as a fourth valve unit  60 D. In the following, the first valve unit  60 A, the second valve unit  60 B, the third valve unit  60 C, and the fourth valve unit  60 D are referred to as the valve unit  60  when the distinction is necessary. 
     Here, the valve unit  60  will be described with reference to  FIGS.  11  to  13   . It should be noted that  FIG.  11    is a side view of the valve unit  60  as viewed in the −W direction.  FIGS.  12  and  13    are cross-sectional views taken along the lines XII-XII and XIII-XIII of  FIG.  11   . In addition,  FIG.  12    shows a valve closed state, and  FIG.  13    shows a valve open state. Further, in  FIGS.  11  to  13   , L, W, and H represent three spatial axes orthogonal to each other. In the present specification, the directions along these axes are referred to as an L direction, a W direction, and an H direction. In the description, a direction in which an arrow in each figure is directed is referred to as a positive (+) direction, and an opposite direction of the arrow is referred to as a negative (−) direction. 
     The valve unit  60  closes an internal valve to prevent the ink from being supplied to the liquid ejecting section side when the pressure on the liquid ejecting section  20  side is equal to or higher than a predetermined pressure, and opens the internal valve to supply the ink supplied from the liquid storage section to the liquid ejecting section side when the pressure on the liquid ejecting section side is lower than the predetermined pressure. The valve unit  60  can also be referred to as a “self-sealing valve” or a “differential pressure valve”. The valve unit  60  also plays a role of partitioning a negative pressure state in the liquid ejecting section and a positive pressure state on the liquid supply section side such that a pressurizing force does not directly act on the liquid ejecting section in a negative pressure state from the liquid storage section. 
     As shown in  FIGS.  11  to  13   , the valve unit  60  includes a valve unit main body  61 , a valve body  62 , and a flexible film  63 . In addition, the valve unit  60  has a valve unit flow path  64  that communicates with the liquid storage section  4  and the liquid ejecting section  20 . The valve unit flow path  64  includes a supply path  641  coupled to the liquid storage section  4 , a liquid supply chamber  642  coupled to the supply path  641 , a discharge path  643  coupled to the liquid ejecting section  20  side, and a pressure chamber  644  coupled to the discharge path. The liquid supply chamber  642  and the pressure chamber  644  are arranged side by side in this order in the +W direction, and the liquid supply chamber  642  and the pressure chamber  644  are partitioned by a flow path partition wall  65 . The flow path partition wall  65  is formed with a communication hole  651  that communicates the liquid supply chamber  642  and the pressure chamber  644 . That is, the ink from the liquid storage section  4  is supplied to the liquid supply chamber  642  via the supply path  641 . In addition, the ink in the liquid supply chamber  642  is supplied to the pressure chamber  644  via the communication hole  651 . Moreover, the ink in the pressure chamber  644  is supplied to the liquid ejecting section  20  via the discharge path  643 . 
     The pressure chamber  644  has a recessed shape that is open on the surface of the valve unit main body  61  in the +W direction. The pressure chamber  644  is sealed by the flexible film  63  fixed to the surface of the valve unit main body  61 . That is, the flexible film  63  defines a part of the pressure chamber  644 . For the flexible film  63 , a flexible material having resistance to the ink can be used. In addition, as the flexible film  63 , it is preferable to use a material having a low water permeability or a low gas permeability of liquid oxygen, nitrogen, or the like. Examples of the material of the flexible film  63  include a configuration in which a nylon film coated with vinylidene chloride (Saran) is adhered and laminated to a high-density polyethylene film or a polypropylene (PP) film. In addition, polyethylene terephthalate (PET) or the like may be used as another material of the flexible film  63 . In addition, as a method of joining the flexible film  63  to the valve unit main body  61 , for example, heat welding, vibration welding, adhesion with an adhesive or the like can be used. 
     An inner surface of the pressure chamber  644  defined by the flexible film  63 , that is, the surface on the −W direction side is referred to as an inner surface  631 , and the surface of the flexible film  63  opposite to the inner surface  631 , that is, the surface on the +W direction side is referred to as an outer surface  632  in contact with the atmosphere. It should be noted that the inner surface  631  of the flexible film  63  refers to a portion of the flexible film  63  that defines the pressure chamber  644 , that is, a portion that overlaps with an opening of the pressure chamber  644  in the +W direction. In addition, the outer surface  632  of the flexible film  63  means a portion that overlaps with the inner surface  631  as viewed in the −W direction. That is, the inner surface  631  and the outer surface  632  of the flexible film  63  refer to a so-called diaphragm region that is displaced due to the differential pressure between the inside and the outside of the pressure chamber  644 . It should be noted that the flexible film  63  is joined to the valve unit main body  61  on the outside of the inner surface  631 . In addition, the flexible film  63  can be displaced in the −W direction toward the inner surface  631  from the outer surface  632  and in the +W direction opposite to the −W direction. 
     Further, a pressure reception plate  66  is disposed on the inner surface  631  of the flexible film  63 . The pressure reception plate  66  is made of a material having a Young&#39;s modulus higher than the flexible film  63 , for example, a thin plate, such as SUS, or a resin. In the present embodiment, the pressure reception plate  66  is constituted by a plate-shaped member having an outer diameter smaller than the inner surface  631  of the flexible film  63 , and is joined to the inner surface of the flexible film  63 , that is, the region that defines the pressure chamber  644 . Therefore, the pressure reception plate  66  can be moved in the +W direction and the −W direction in accordance with the bending deformation of the flexible film  63 . It should be noted that the pressure reception plate  66  is not particularly limited to this, and one end of the pressure reception plate  66  may be supported at a joint portion between the valve unit main body  61  and the flexible film  63 . That is, the pressure reception plate  66  may be bent and deformed like a plate spring. When one end of the pressure reception plate  66  is supported between the valve unit main body  61  and the flexible film  63  in this way, the pressure reception plate  66  and the flexible film  63  may or may not be joined. 
     The valve body  62  has a base end portion  621  accommodated in the liquid supply chamber  642 , a shaft portion  622  protruding from the base end portion  621  through the communication hole  651  to the pressure chamber  644  side, and an elastic member  623  provided on the +W direction side of the base end portion  621 . The base end portion  621  has a substantially disk-shaped shape, and is larger than the outer diameter in a cross section perpendicular to the +W direction of the shaft portion. The base end portion  621  can also be referred to as a flange portion. The shaft portion  622  passes through the communication hole  651  formed in the flow path partition wall  65 , and a distal end portion thereof is positioned in the pressure chamber  644 . The distal end portion of the shaft portion  622  can come into contact with the flexible film  63  that defines a part of the pressure chamber  644  via the pressure reception plate  66 . The ink in the liquid supply chamber  642  flows into the pressure chamber  644  through an interval between the shaft portion  622  and the inner surface of the communication hole  651 . The elastic member  623  is provided inside the outer circumferences of the base end portion  621  and outside the shaft portion  622  as viewed in the −W direction. A protrusion is formed on the +W direction side of the elastic member  623  at a portion coming in contact with a valve seat  652 . 
     The valve seat  652  having an annular shape is provided around the communication hole  651  on the surface of the flow path partition wall  65  on the liquid supply chamber  642  side in the −W direction. The valve seat  652  is a sealing portion that blocks the communication hole  651  by coming into contact with the elastic member  623  provided on the valve body  62 . The valve seat  652  according to the present embodiment is separate from the flow path partition wall  65 , and is formed of, for example, a metal, such as SUS or titanium. In addition, the surface of the valve seat  652  coming into contact with the elastic member  623  in the −W direction may be subjected to liquid repellent treatment, such as a fluorine coating. 
     In the liquid supply chamber  642 , a coil spring  67 , which is an example of an urging member, is interposed between the base end portion  621  of the valve body  62  and the valve unit main body  61  that defines the inner surface of the liquid supply chamber  642  in the −W direction. The valve body  62  is urged by the coil spring  67  in the +W direction. It should be noted that, as the urging member, for example, a plate spring or a disk spring can be used in addition to the coil spring  67 . In addition, the pressure chamber  644  may be provided with the urging member, such as the coil spring, that urges the flexible film  63  with respect to the valve unit main body  61  in the +W direction. 
     An opening/closing operation of the valve unit  60  configured as described above will be described. In the following description, a state is assumed in which the liquid supply chamber  642  and the pressure chamber  644  are filled with the ink by the initial filling of the nozzle  21  with the ink or the previous ejection of the ink. As shown in  FIG.  12   , the coil spring  67  urges the valve body  62  in the +W direction, which is the direction in which the valve body  62  is always in the valve closed state. In the valve closed state in which the valve body  62  is positioned in the +W direction, the elastic member  623  is in a state of coming into contact with the valve seat  652  to block the communication hole  651 , that is, the liquid supply chamber  642  and the pressure chamber  644  are in a non-communication state. In the present embodiment, a position of the valve body  62  at which the valve unit flow path  64  is closed is referred to as a closing position. At the closing position of the valve body  62 , the distal end of the shaft portion  622  of the valve body  62  may or may not come into contact with the pressure reception plate  66 . 
     In the non-communication state of the liquid supply chamber  642  and the pressure chamber  644 , when the ink is ejected from the liquid ejecting section  20 , the ink in the pressure chamber  644  is decreased. As a result, as shown in  FIG.  13   , the inside of the pressure chamber  644  has a negative pressure due to the differential pressure with the pressure on the outer surface  632  side of the flexible film  63 , that is, the atmospheric pressure, and the flexible film  63  and the pressure reception plate  66  are displaced to bend in the −W direction on the liquid supply chamber  642  side. Then, the pressure reception plate  66  pushes the distal end of the shaft portion  622  in the −W direction, and the valve body  62  is pushed down to the liquid supply chamber  642  side against the urging force of the coil spring  67 . As a result, the elastic member  623  is separated from the valve seat  652  due to the movement of the valve body  62  in the −W direction, and the valve body  62  is in the valve open state. Moreover, when the valve body  62  is in the valve open state, it is a state in which the communication hole  651  is open, that is, the valve open state in which the liquid supply chamber  642  and the pressure chamber  644  communicate with each other. In the present embodiment, the position of the valve body  62  at which the valve unit flow path  64  is opened is referred to as an opening position. That is, the valve body  62  is moved between the closing position and the opening position due to the displacement of the flexible film  63 . At the opening position of the valve body  62 , the distal end of the shaft portion  622  of the valve body  62  comes into contact with the pressure reception plate  66 . 
     When the valve body  62  is in the valve open state, the ink in the liquid supply chamber  642  flows into the pressure chamber  644  via the communication hole  651 . When the pressure chamber  644  is sufficiently replenished with the ink, the negative pressure in the pressure chamber  644  is eliminated, the flexible film  63  and the pressure reception plate  66  return to original positions thereof, and the valve body  62  is in the valve closed state due to the urging force of the coil spring  67  as shown in  FIG.  12   . By the opening/closing operation of the valve body  62  in this way, the ink in the pressure chamber  644  is adjusted such that the pressure is always substantially fixed. 
     Four such valve units  60  are disposed in the recording head  10 . Here, the disposition of the valve unit  60  disposed in the recording head  10  with respect to the support  3  will be mainly described with reference to  FIG.  10   . 
     The first valve unit  60 A is disposed such that the +H direction matches the −Z direction, the +W direction matches the +Y direction, and the +L direction matches the +X direction, with respect to the flow path member  50 . In such a first valve unit  60 A, the valve unit flow path  64  of the valve unit  60  described above is a “first flow path  64 A” that communicates with the liquid ejecting section  20 . In addition, the flexible film  63  of the valve unit  60  is a “first flexible film  63 A” in the first valve unit  60 A. In addition, the pressure reception plate  66  of the valve unit  60  is a “first pressure reception plate  66 A” in the first valve unit  60 A. In addition, the valve body  62  of the valve unit  60  is a “first valve body  62 A” in the first valve unit  60 A. Moreover, the inner surface  631  of the first flexible film  63 A in the first valve unit  60 A is a “first inner surface  631 A”, and the outer surface  632  of the first flexible film  63 A is a “first outer surface  632 A”. The −W direction from the first outer surface  632 A to the first inner surface  631 A matches the −Y direction. In the following, the first direction from the first outer surface  632 A to the first inner surface  631 A will be described as the −Y direction. In addition, the +W direction, which is the opposite direction to the −W direction, matches the +Y direction. In the following, the second direction will be described as the +Y direction. Further, the third direction orthogonal to the −Y direction, which is the first direction, is the direction along the X axis and the direction along the Z axis, but in the present embodiment, the third direction is the +X direction orthogonal to the +Z direction, which is the ejection direction. In the following, in the present embodiment, the third direction will be described as the +X direction. 
     In the second valve unit  60 B, the +H direction matches the −Z direction, the +W direction matches the −Y direction, and the +L direction matches the −X direction, with respect to the flow path member  50 . That is, the second valve unit  60 B is disposed such that the valve unit  60  is rotated 180 degrees with respect to the first valve unit  60 A about an imaginary axis along the +H direction. In such a second valve unit  60 B, the valve unit flow path  64  of the valve unit  60  described above is a “second flow path  64 B” that communicates with the liquid ejecting section  20 . In addition, the flexible film  63  of the valve unit  60  is a “second flexible film  63 B” in the second valve unit  60 B. In addition, the pressure reception plate  66  of the valve unit  60  is a “second pressure reception plate  66 B” in the second valve unit  60 B. In addition, the valve body  62  of the valve unit  60  is a “second valve body  62 B” in the second valve unit  60 B. Moreover, the inner surface  631  of the second flexible film  63 B in the second valve unit  60 B is a “second inner surface  631 B”, and the outer surface  632  of the second flexible film  63 B is a “second outer surface  632 B”. Such a second valve unit  60 B is disposed such that the direction from the second outer surface  632 B to the second inner surface  631 B is the +Y direction, which is the second direction, and the direction from the second inner surface  631 B to the second outer surface  632 B is the −Y direction, which is the first direction. 
     The third valve unit  60 C is held by the flow path member  50  in the same posture as the first valve unit  60 A. That is, the third valve unit  60 C is disposed such that the +H direction matches the −Z direction, the +W direction matches the +Y direction, and the +L direction matches the +X direction, with respect to the flow path member  50 . In such a third valve unit  60 C, the valve unit flow path  64  of the valve unit  60  is a “third flow path  64 C” that communicates with the liquid ejecting section  20 . In addition, the flexible film  63  of the valve unit  60  is a “third flexible film  63 C” in the third valve unit  60 C. In addition, the pressure reception plate  66  of the valve unit  60  is a “third pressure reception plate  66 C” in the third valve unit  60 C. In addition, the valve body  62  of the valve unit  60  is a “third valve body  62 C” in the third valve unit  60 C. Moreover, the inner surface  631  of the third flexible film  63 C in the third valve unit  60 C is a “third inner surface  631 C”, and the outer surface  632  of the third flexible film  63 C is a “third outer surface  632 C”. Such a third valve unit  60 C is disposed such that the direction from the third outer surface  632 C to the third inner surface  631 C is the −Y direction, which is the first direction, and the direction from the third inner surface  631 C to the third outer surface  632 C is the +Y direction, which is the second direction. 
     The fourth valve unit  60 D is held by the flow path member  50  in the same posture as the second valve unit  60 B. That is, in the fourth valve unit  60 D, the +H direction matches the −Z direction, the +W direction matches the −Y direction, and the +L direction matches the −X direction, with respect to the holder  30 . In such a fourth valve unit  60 D, the valve unit flow path  64  of the valve unit  60  described above is a “fourth flow path  64 D” that communicates with the liquid ejecting section  20 . In addition, the flexible film  63  of the valve unit  60  is a “fourth flexible film  63 D” in the fourth valve unit  60 D. In addition, the pressure reception plate  66  of the valve unit  60  is a “fourth pressure reception plate  66 D” in the fourth valve unit  60 D. In addition, the valve body  62  of the valve unit  60  is a “fourth valve body  62 D” in the fourth valve unit  60 D. Moreover, the inner surface  631  of the fourth flexible film  63 D in the fourth valve unit  60 D is a “fourth inner surface  631 D”, and the outer surface  632  of the fourth flexible film  63 D is a “fourth outer surface  632 D”. Such a fourth valve unit  60 D is disposed such that the direction from the fourth outer surface  632 D to the fourth inner surface  631 D is the +Y direction, which is the second direction, and the direction from the fourth inner surface  631 D to the fourth outer surface  632 D is the −Y direction, which is the first direction. 
     Here, the first valve unit  60 A and the second valve unit  60 B are disposed at the same position in the +Z direction as shown in  FIGS.  6  and  9   . In addition, the second valve unit  60 B and the third valve unit  60 C are disposed at the same position in the +Z direction. Further, the third valve unit  60 C and the fourth valve unit  60 D are disposed at the same position in the +Z direction. That is, in the present embodiment, the first valve unit  60 A, the second valve unit  60 B, the third valve unit  60 C, and the fourth valve unit  60 D are disposed at the same position in the +Z direction. It should be noted that the fact that two members are disposed at the same position in the +Z direction means that the coordinates of the centers of two members along the Z axis are at the same position on the Z axis. By disposing all the valve units  60  at the same position in the +Z direction in this way, the size of the recording head  10  can be reduced in the +Z direction. Of course, any one or a plurality of two or more of the first valve unit  60 A, the second valve unit  60 B, the third valve unit  60 C, and the fourth valve unit  60 D may be disposed at different positions in the +Z direction with respect to the others. 
     In addition, as shown in  FIG.  10   , the second valve unit  60 B is disposed to overlap with a part of the first valve unit  60 A as viewed in the −Y direction, which is the first direction, to deviate from the first valve unit  60 A in the +Y direction, which is the second direction, and the +X direction, which is the third direction. That is, as viewed in the −Y direction, an end portion of the second valve unit  60 B in the −X direction is disposed to overlap with an end portion of the first valve unit  60 A in the +X direction. In addition, as viewed in the −Y direction, an end portion of the second valve unit  60 B in the +X direction does not overlap with the first valve unit  60 A, and an end portion of the first valve unit  60 A in the −X direction is disposed at a position that does not overlap with the second valve unit  60 B. 
     In addition, at least a part of the first outer surface  632 A of the first valve unit  60 A does not overlap with the second valve unit  60 B as viewed in the −Y direction. In the present embodiment, the first outer surface  632 A and the second valve unit  60 B partially overlap with each other as viewed in the −Y direction. That is, in the present embodiment, as viewed in the −Y direction, an end portion of the first outer surface  632 A in the +X direction overlaps with the second valve unit  60 B, and an end portion thereof in the −X direction does not overlap with the second valve unit  60 B. Of course, the first outer surface  632 A and the second valve unit  60 B may be disposed at positions that do not completely overlap with each other as viewed in the −Y direction. It should be noted that, by disposing the first outer surface  632 A and the second valve unit  60 B to partially overlap with each other as viewed in the −Y direction, the size of the recording head  10  can be reduced in the +X direction. 
     Further, at least a part of the second outer surface  632 B of the second valve unit  60 B does not overlap with the first valve unit  60 A as viewed in the +Y direction. 
     In the present embodiment, the second outer surface  632 B and the first valve unit  60 A partially overlap with each other as viewed in the +Y direction. That is, in the present embodiment, as viewed in the +Y direction, an end portion of the second outer surface  632 B in the −X direction overlaps with the first valve unit  60 A, and an end portion thereof in the +X direction does not overlap with the second valve unit  60 B. Of course, the second outer surface  632 B and the first valve unit  60 A may be disposed not to completely overlap with each other as viewed in the +Y direction. It should be noted that, by disposing the second outer surface  632 B and the first valve unit  60 A to partially overlap with each other as viewed in the +Y direction, the size of the recording head  10  can be reduced in the +X direction. 
     In addition, at least a part of the second outer surface  632 B of the second valve unit  60 B does not overlap with the third valve unit  60 C as viewed in the +Y direction. In the present embodiment, the second outer surface  632 B and the third valve unit  60 C partially overlap with each other as viewed in the +Y direction. That is, in the present embodiment, as viewed in the +Y direction, an end portion of the second outer surface  632 B in the +X direction overlaps with the third valve unit  60 C, and an end portion thereof in the −X direction does not overlap with the third valve unit  60 C. Of course, the second outer surface  632 B and the third valve unit  60 C may be disposed not to completely overlap with each other as viewed in the +Y direction. It should be noted that, by disposing the second outer surface  632 B and the third valve unit  60 C to partially overlap with each other as viewed in the +Y direction, the size of the recording head  10  can be reduced in the +X direction. 
     That is, the second outer surface  632 B of the second flexible film  63 B of the second valve unit  60 B overlaps with both the first valve unit  60 A and the third valve unit  60 C as viewed in the +Y direction. 
     The third valve unit  60 C is disposed in the +X direction, which is the third direction, with respect to the first valve unit  60 A. In the present embodiment, the first valve unit  60 A and the third valve unit  60 C are disposed at the same position in the +Y direction and different positions in the +X direction. That is, the first valve unit  60 A is disposed in the −X direction with respect to the third valve unit  60 C, and the third valve unit  60 C is disposed in the +X direction with respect to the first valve unit  60 A. Of course, the first valve unit  60 A and the third valve unit  60 C may be disposed to deviate from each other in the direction along the Y axis. It should be noted that, by disposing the first valve unit  60 A and the third valve unit  60 C at positions that at least partially overlap with each other as viewed in the +X direction, the size of the recording head  10  can be reduced in the +Y direction. 
     In addition, the third valve unit  60 C is disposed to overlap with a part of the second valve unit  60 B as viewed in the +Y direction, which is the second direction. That is, the third valve unit  60 C is disposed such that a part of the third valve unit  60 C in the −X direction and a part of the second valve unit  60 B in the +X direction overlap with each other as viewed in the +Y direction. 
     In addition, a part of the third outer surface  632 C of the third valve unit  60 C does not overlap with the second valve unit  60 B as viewed in the −Y direction. In the present embodiment, the third outer surface  632 C and the second valve unit  60 B partially overlap with each other as viewed in the −Y direction. That is, in the present embodiment, as viewed in the −Y direction, an end portion of the third outer surface  632 C in the −X direction overlaps with the second valve unit  60 B and an end portion thereof in the +X direction does not overlap with the second valve unit  60 B. Of course, the third outer surface  632 C and the second valve unit  60 B may be disposed not to completely overlap with each other as viewed in the −Y direction. It should be noted that, by disposing the third outer surface  632 C and the second valve unit  60 B to partially overlap with each other as viewed in the +X direction, the size of the recording head  10  can be reduced in the +Y direction. 
     In addition, the third valve unit  60 C is disposed to overlap with a part of the fourth valve unit  60 D as viewed in the +Y direction. That is, the third valve unit  60 C is disposed such that a part of the third valve unit  60 C in the +X direction and a part of the fourth valve unit  60 D in the −X direction overlap with each other as viewed in the +Y direction. 
     In addition, at least a part of the third outer surface  632 C of the third valve unit  60 C does not overlap with the fourth valve unit  60 D as viewed in the −Y direction. In the present embodiment, the third outer surface  632 C and the fourth valve unit  60 D partially overlap with each other as viewed in the −Y direction. That is, in the present embodiment, as viewed in the −Y direction, an end portion of the third outer surface  632 C in the +X direction overlaps with the fourth valve unit  60 D and an end portion thereof in the −X direction does not overlap with the fourth valve unit  60 D. Of course, the third outer surface  632 C and the fourth valve unit  60 D may be disposed not to completely overlap with each other as viewed in the +X direction. It should be noted that, by disposing the third outer surface  632 C and the fourth valve unit  60 D to partially overlap with each other as viewed in the −Y direction, the size of the recording head  10  can be reduced in the +Y direction. 
     That is, the third outer surface  632 C of the third valve unit  60 C overlaps with the second valve unit  60 B and the fourth valve unit  60 D as viewed in the −Y direction. 
     The fourth valve unit  60 D is disposed in the +Y direction, which is the third direction, with respect to the second valve unit  60 B. In the present embodiment, the second valve unit  60 B and the fourth valve unit  60 D are disposed at the same position in the +Y direction and different positions in the +X direction. That is, the second valve unit  60 B is disposed in the −X direction with respect to the fourth valve unit  60 D, and the fourth valve unit  60 D is disposed in the +X direction with respect to the second valve unit  60 B. Of course, the second valve unit  60 B and the fourth valve unit  60 D may be disposed to deviate from each other in the direction along the Y axis. It should be noted that, by disposing the second valve unit  60 B and the fourth valve unit  60 D at positions that at least partially overlap with each other as viewed in the +X direction, so that the size of the recording head  10  can be reduced in the +Y direction. 
     In addition, the fourth valve unit  60 D is disposed to overlap with a part of the third valve unit  60 C as viewed in the +Y direction, which is the second direction, as described above. That is, the fourth valve unit  60 D is disposed such that a part of the fourth valve unit  60 D in the −X direction and a part of the third valve unit  60 C in the +X direction overlap with each other as viewed in the +Y direction. 
     In addition, at least a part of the fourth outer surface  632 D of the fourth valve unit  60 D does not overlap with the third valve unit  60 C as viewed in the +Y direction. In the present embodiment, the fourth outer surface  632 D and the third valve unit  60 C partially overlap with each other as viewed in the +Y direction. That is, in the present embodiment, as viewed in the +Y direction, an end portion of the fourth outer surface  632 D in the −X direction overlaps with the third valve unit  60 C, and an end portion thereof in the +X direction does not overlap with the third valve unit  60 C. Of course, the fourth outer surface  632 D and the third valve unit  60 C may be disposed not to completely overlap with each other as viewed in the +Y direction. It should be noted that, by disposing the fourth outer surface  632 D and the third valve unit  60 C to partially overlap with each other as viewed in the +Y direction, the size of the recording head  10  can be reduced in the +X direction. 
     As described above, the four valve units  60  according to the present embodiment are disposed such that, as viewed in the direction along the Y axis, the first outer surface  632 A and the second valve unit  60 B partially overlap with each other, the second outer surface  632 B, and the first valve unit  60 A and the third valve unit  60 C partially overlap with each other, the third outer surface  632 C and the second valve unit  60 B and the fourth valve unit  60 D partially overlap with each other, and the fourth outer surface  632 D and the third valve unit  60 C partially overlap with each other. Therefore, as compared with when the outer surface  632  of one valve unit  60  is disposed not to overlap with the other valve unit  60  as viewed in the direction along the Y axis, the size of the recording head  10  in the direction along the X axis can be reduced. 
     It should be noted that, in the present embodiment, as viewed in the direction along the Z axis, a part of the first valve unit  60 A, the second valve unit  60 B, the third valve unit  60 C, and a part of the fourth valve unit  60 D overlap with the first portion P 1 , a part of the first valve unit  60 A overlaps with the second portion P 2 , and a part of the fourth valve unit  60 D overlaps with the third portion P 3 . 
     In addition, the four valve units  60  disposed in this way are covered with the cover  70 . The cover  70  is fixed to the surface of the flow path member  50  in the −Z direction and covers the valve unit  60  with the flow path member  50 . Specifically, the cover  70  is formed with a valve unit accommodation section  71  that is open in the +Z direction. The valve unit accommodation section  71  has a recessed shape that is open on the surface in the +Z direction, and an opening of the valve unit accommodation section  71  in the +Z direction is covered with the flow path member  50 . The valve unit accommodation section  71  is provided independently for each valve unit  60 , and one valve unit  60  is accommodated in each of the valve unit accommodation sections  71 . That is, in the present embodiment, a “housing” that accommodates the liquid ejecting section  20  and the valve unit  60  is constituted by the fixing plate  40 , the holder  30 , the flow path member  50 , and the cover  70 . It should be noted that the cover  70  may be divided into two or more portions. In addition, since the valve unit accommodation section  71  is independently provided for each valve unit  60 , on the cover  70 , the valve unit accommodation section  71  in which the first valve unit  60 A is accommodated and the valve unit accommodation section  71  in which the third valve unit  60 C is accommodated are partitioned by a first partition wall  72 A, which is a partition wall. Similarly, the valve unit accommodation section  71  in which the second valve unit  60 B is accommodated and the valve unit accommodation section  71  in which the fourth valve unit  60 D is accommodated are partitioned by a second partition wall  72 B which is the partition wall. 
     The cover  70  has a first opening portion  73  formed at a position facing at least a part of the first outer surface  632 A of the first valve unit  60 A. The first opening portion  73  penetrates the cover  70  along the Y axis to communicate the inside and the outside of the valve unit accommodation section  71 . That is, a part of the first outer surface  632 A of the first valve unit  60 A is exposed to the outside by the first opening portion  73  provided in the cover  70 . By exposing the first outer surface  632 A of the first flexible film  63 A to the outside of the cover  70 , that is, the outside of the valve unit accommodation section  71  by the first opening portion  73  in this way, the first flexible film  63 A can be pressed from the outside of the cover  70  in the −Y direction, which is the first direction. Therefore, even when the differential pressure between the pressure on the first inner surface  631 A side and the pressure on the first outer surface  632 A side, that is, the atmospheric pressure of the pressure chamber  644  of the first valve unit  60 A is not equal to or higher than the predetermined pressure, the first flexible film  63 A can be moved to the −Y direction to move the first valve body  62 A to the −X direction, and the valve open state can be obtained in which the liquid supply chamber  642  and the pressure chamber  644  of the first flow path  64 A communicate with each other. In the present embodiment, an operation of pressing the outer surface  632  of the flexible film  63  in the valve unit  60  by an external force other than the differential pressure between the inner surface  631  and the outer surface  632  to move the valve body  62  and open the valve is referred to as forcible valve opening. 
     The forcible valve opening is performed, for example, by so-called initial filling in which the recording head  10  in an empty state in which the ink used for printing is not filled is filled with the ink used for printing, or a cleaning operation of discharging the ink from the nozzle  21 . By providing the first opening portion  73  in this way, the first flexible film  63 A can be operated from the outside of the cover  70 , so that it is not necessary to provide the mechanism that operates the first flexible film  63 A inside the cover  70 , that is, inside the valve unit accommodation section  71 , and the size of the recording head  10  can be reduced, the structure thereof can be simplified, and the forcible valve opening can be easily performed. 
     It should be noted that, it is preferable that the first opening portion  73  overlap with at least a part of the first valve body  62 A as viewed in the −Y direction, which is the first direction. In the present embodiment, a part of the first opening portion  73  on the +X direction side is disposed at a position that overlaps with the −X direction side of the first valve body  62 A. By providing the first opening portion  73  to overlap with the first valve body  62 A as viewed in the −Y direction in this way, when the first flexible film  63 A is pressed in the −Y direction for the forcible valve opening, the movement of the valve body  62  in the −Y direction can be stabilized. By the way, when the forcible valve opening is performed, by pressing the first flexible film  63 A at a position as close as possible to the shaft portion  622  of the first valve body  62 A, the force applied to the shaft portion  622  in the direction inclined with respect to the Y axis can be decreased, so that the valve body  62  can be stably moved along the Y axis. Therefore, it is further preferable that the first opening portion  73  be disposed to overlap with the shaft portion  622  of the first valve body  62 A as viewed in the −Y direction. 
     In addition, it is preferable that the first opening portion  73  overlap with at least a part of the first pressure reception plate  66 A as viewed in the −Y direction, which is the first direction. It should be noted that, when the first opening portion  73  is provided at a position that overlaps with the first pressure reception plate  66 A, the first opening portion  73  may or may not overlap with at least a part of the first valve body  62 A as viewed in the −Y direction. By providing the first opening portion  73  to overlap with the first pressure reception plate  66 A as viewed in the −Y direction in this way, when the first flexible film  63 A is pressed in the −Y direction via the first opening portion  73 , the pressure reception plate  66  can be pressed, and the movement of the first valve body  62 A that is moved by the first pressure reception plate  66 A can be stabilized. Therefore, the forcible valve opening can be stably performed. 
     In addition, as described above, the first valve unit  60 A is disposed not to partially overlap with the second valve unit  60 B as viewed in the −Y direction. Therefore, the first opening portion  73  can be formed further relatively wide in the −Y direction at a position in the −Y direction of the second valve unit  60 B. 
     In addition, it is preferable that a gap t 1  between a portion facing the first outer surface  632 A at a position different from the first opening portion  73  on an inner wall surface  71   a  forming the valve unit accommodation section  71  of the cover  70 , and the first outer surface  632 A be smaller than a dimension W 1  of the first valve unit  60 A in the −Y direction. In addition, it is further preferable that the gap t 1  be smaller than ½ of the dimension W 1  of the first valve unit  60 A. Here, the gap t 1  between the portion facing the first outer surface  632 A and the first outer surface  632 A on the inner wall surface  71   a  is the minimum dimension in a state in which the first flexible film  63 A is most displaced in the +Y direction. In addition, the dimension W 1  of the first valve unit  60 A in the −Y direction is the maximum dimension in a state in which the first flexible film  63 A is most displaced in the +Y direction. By making the gap t 1  between the first outer surface  632 A and the inner wall surface  71   a  smaller than the dimension W 1  of the first valve unit  60 A in the −Y direction, the size of the recording head  10  can be reduced in the +Y direction. 
     In addition, it is preferable that the gap t 1  between the portion facing the first outer surface  632 A at a position different from the first opening portion  73  on the inner wall surface  71   a  forming the valve unit accommodation section  71  of the cover  70 , and the first outer surface  632 A be smaller than a maximum displacement amount D 1  (see  FIG.  13   ) of the first flexible film  63 A in the −Y direction. Here, the maximum displacement amount D 1  of the first flexible film  63 A in the −Y direction is the dimension of a portion positioned most in the −Y direction when the first flexible film  63 A is displaced in the −Y direction, and a portion positioned most in the +Y direction when the first flexible film  63 A is displaced in the +Y direction. By making the gap t 1  between the first outer surface  632 A and the inner wall surface  71   a  smaller than the maximum displacement amount D 1  of the first flexible film in this way, the size of the recording head  10  can be reduced in the +Y direction. 
     The cover  70  has a second opening portion  74  formed at a position facing at least a part of the second outer surface  632 B of the second valve unit  60 B. The second opening portion  74  penetrates the cover  70  along the Y axis to communicate the inside and the outside of the valve unit accommodation section  71 . That is, a part of the second outer surface  632 B of the second valve unit  60 B is exposed to the outside by the second opening portion  74  provided in the cover  70 . By exposing the second outer surface  632 B of the second flexible film  63 B to the outside of the cover  70  by the second opening portion  74  in this way, the second flexible film  63 B can be pressed from the outside of the cover  70  in the +Y direction. Therefore, it is possible to forcibly open the second valve unit  60 B from the outside of the cover  70 . 
     In addition, as described above, at least a part of the second outer surface  632 B of the second valve unit  60 B does not overlap with the first valve unit  60 A as viewed in the +Y direction. In addition, at least a part of the second outer surface  632 B does not overlap with the third valve unit  60 C as viewed in the +Y direction. Therefore, the second opening portion  74  is provided at a position on the second outer surface  632 B that does not overlap with the first valve unit  60 A and the third valve unit  60 C as viewed in the +Y direction. That is, the second opening portion  74  is provided between the first valve unit  60 A and the third valve unit  60 C. Specifically, the second opening portion  74  is provided in the first partition wall  72 A between the valve unit accommodation section  71  that accommodates the first valve unit  60 A and the valve unit accommodation section  71  that accommodates the third valve unit  60 C to penetrate in the direction along the Y axis. The second opening portion  74  is formed to have the same opening area in the direction along the Y axis. In addition, a dimension of the first partition wall  72 A in the direction along the Y axis, that is, the distance L 2  along the Y axis of the second opening portion  74  is larger than a maximum width W 1  of the valve unit  60  along the Y axis. The maximum width W 1  along the Y axis of the valve unit  60  is the maximum dimension in a state in which the flexible film  63  is most displaced toward a side opposite to the valve unit main body  61 . 
     Here, a distance L 1  from one end of the first opening portion  73  to the other end thereof is shorter than a distance L 2  from one end of the second opening portion  74  to the other end thereof. That is, L 1 &lt;L 2 . It should be noted that the distance L 1  from one end of the first opening portion  73  to the other end thereof is the distance from the opening of the first opening portion  73  in the −Y direction along the Y axis to the opening thereof in the +Y direction. Similarly, the distance L 2  from one end of the second opening portion  74  to the other end thereof is the distance from the opening of the second opening portion  74  in the −Y direction to the opening thereof in the +Y direction along the Y axis. 
     In addition, it is preferable that an area of the first opening portion  73  be larger than an area of the second opening portion  74 . Here, the areas of the first opening portion  73  and the second opening portion  74  are the areas of the opening portions on the outer surface of the cover  70 . The first outer surface  632 A has a portion that is not covered with the second valve unit  60 B as viewed in the −Y direction, and the valve unit  60  is not disposed in the −X direction with respect to the second valve unit  60 B, so that the first opening portion  73  can be provided by expanding a width Wa in the −X direction. On the other hand, the second outer surface  632 B overlaps both the first valve unit  60 A and the third valve unit  60 C as viewed in the +Y direction, and the second opening portion  74  is provided in the first partition wall  72 A, so that a width Wb of the second opening portion  74  along the X axis is relatively small. Therefore, since the width Wa of the first opening portion  73  in the direction along the X axis can be made larger than the width Wb of the second opening portion  74 , the area of the first opening portion  73  can be made larger than the area of the second opening portion  74  provided in the first partition wall  72 A. 
     In addition, it is preferable that the gap t 1  between a portion facing the first outer surface  632 A at a position different from the first opening portion  73  on the inner wall surface  71   a  of the cover  70 , and the first outer surface  632 A be narrower than an interval t 2  between of the first valve unit  60 A and the second valve unit  60 B in the −Y direction. That is, it is preferable that t 1 &lt;t 2 . The interval t 2  between the first valve unit  60 A and the second valve unit  60 B in the −Y direction is a distance in the −Y direction between a position at which the first flexible film  63 A is most displaced toward a side opposite to the valve unit main body  61  of the first valve unit  60 A, and a position at which the second flexible film  63 B is most displaced toward a side opposite to the valve unit main body  61  of the second valve unit  60 B. By making the gap t 1  smaller than the interval t 2  in this way, the size of the recording head  10  can be reduced in the direction along the Y axis. 
     In addition, similarly to the first opening portion  73  described above, it is preferable that the second opening portion  74  overlap with at least a part of the second valve body  62 B as viewed in the +Y direction. In addition, it is preferable that the second opening portion  74  overlap with at least a part of the second pressure reception plate  66 B as viewed in the +Y direction. As described above, by providing the second opening portion  74  at a position that overlaps with the second valve body  62 B or a position that overlaps with the second pressure reception plate  66 B as viewed in the +Y direction, the movement of the second valve body  62 B can be stabilized when the second flexible film  63 B is pressed from the outside of the cover  70  via the second opening portion  74 . Therefore, the forcible valve opening of the second valve unit  60 B can be stably performed. 
     The cover  70  has a third opening portion  75  formed at a position facing at least a part of the third outer surface  632 C of the third valve unit  60 C. The third opening portion  75  penetrates the cover  70  along the Y axis to communicate the inside and the outside of the valve unit accommodation section  71 . That is, a part of the third outer surface  632 C of the third valve unit  60 C is exposed to the outside by the third opening portion  75  provided in the cover  70 . By exposing the third outer surface  632 C of the third flexible film  63 C to the outside of the cover  70  by the third opening portion  75  in this way, the third flexible film  63 C can be pressed from the outside of the cover  70  in the −Y direction. Therefore, it is possible to forcibly open the third valve unit  60 C from the outside of the cover  70 . 
     In addition, as described above, at least a part of the third outer surface  632 C of the third valve unit  60 C does not overlap with the second valve unit  60 B as viewed in the −Y direction. In addition, at least a part of the third outer surface  632 C does not overlap with the fourth valve unit  60 D as viewed in the −Y direction. Therefore, the third opening portion  75  is provided at a position on the third outer surface  632 C that does not overlap with the second valve unit  60 B and the fourth valve unit  60 D as viewed in the −Y direction. That is, the third opening portion  75  is provided between the second valve unit  60 B and the fourth valve unit  60 D. Specifically, the third opening portion  75  is provided in the second partition wall  72 B between the valve unit accommodation section  71  that accommodates the second valve unit  60 B and the valve unit accommodation section  71  that accommodates the fourth valve unit  60 D to penetrate in the direction along the Y axis. The third opening portion  75  is formed to have the same opening area in the direction along the Y axis. In addition, a dimension of the second partition wall  72 B in the direction along the Y axis, that is, the distance L 3  along the Y axis of the third opening portion  75  is larger than the maximum width W 1  of the valve unit  60  along the Y axis. 
     Here, a distance L 3  from one end of the third opening portion  75  to the other end thereof is provided with substantially the same dimension as the distance L 2  from one end of the second opening portion  74  to the other end thereof. Therefore, the distance L 1  of the first opening portion  73  is shorter than the distance L 3  of the third opening portion  75 . That is, L 1 &lt;L 3 . 
     In addition, similarly to the first opening portion  73  described above, it is preferable that the third opening portion  75  overlap with at least a part of the third valve body  62 C as viewed in the −Y direction. In addition, it is preferable that the third opening portion  75  overlap with at least a part of the third pressure reception plate  66 C as viewed in the −Y direction. As described above, by providing the third opening portion  75  at a position that overlaps with the third valve body  62 C or a position that overlaps with the third pressure reception plate  66 C as viewed in the −Y direction, the movement of the third valve body  62 C can be stabilized when the third flexible film  63 C is pressed from the outside of the cover  70  via the third opening portion  75 . Therefore, the forcible valve opening of the third valve unit  60 C can be stably performed. 
     The cover  70  has a fourth opening portion  76  formed at a position facing at least a part of the fourth outer surface  632 D of the fourth valve unit  60 D. The fourth opening portion  76  penetrates the cover  70  along the X axis to communicate the inside and the outside of the valve unit accommodation section  71 . That is, a part of the fourth outer surface  632 D of the fourth valve unit  60 D is exposed to the outside by the fourth opening portion  76  provided in the cover  70 . By exposing the fourth outer surface  632 D of the fourth flexible film  63 D to the outside of the cover  70 , that is, the outside of the valve unit accommodation section  71  by the fourth opening portion  76  in this way, the fourth flexible film  63 D can be pressed from the outside of the cover  70  in the +Y direction, which is the second direction. Therefore, it is possible to forcibly open the fourth valve unit  60 D from the outside of the cover  70 . 
     In addition, it is preferable that an area of the fourth opening portion  76  be larger than an area of the third opening portion  75 . Here, the areas of the fourth opening portion  76  and the third opening portion  75  are the areas of the opening portions on the outer surface of the cover  70 . The fourth outer surface  632 D has a portion that is not covered with the third valve unit  60 C as viewed in the +Y direction, and the valve unit  60  is not disposed in the +X direction with respect to the third valve unit  60 C, so that the fourth opening portion  76  can be provided by expanding a width Wd in the +X direction. Therefore, the area of the fourth opening portion  76  is the same as the area of the first opening portion  73 . On the other hand, the third outer surface  632 C overlaps both the second valve unit  60 B and the fourth valve unit  60 D as viewed in the −Y direction, and the third opening portion  75  is provided in the second partition wall  72 B, so that a width Wc of the third opening portion  75  along the X axis is relatively small. In the present embodiment, the opening area of the third opening portion  75  is the same as the area of the second opening portion  74 . Therefore, the width Wd of the fourth opening portion  76  in the direction along the X axis can be made larger than the width Wc of the third opening portion  75 , so that the area of the fourth opening portion  76  can be made larger than the area of the third opening portion  75  provided in the second partition wall  72 B. 
     In addition, it is preferable that the relationship of t 1 , W 1 , t 2 , and D 1  between the first valve unit  60 A and the second valve unit  60 B described above be the same relationship even when the first valve unit  60 A and the second valve unit  60 B are replaced with the fourth valve unit  60 D and the third valve unit  60 C. That is, it is preferable that t 1 , W 1 , t 2 , and D 1  between the fourth valve unit  60 D and the third valve unit  60 C satisfy the relationship described above even when the first valve unit  60 A is replaced with the fourth valve unit  60 D and the second valve unit  60 B is replaced with the third valve unit  60 C. 
     In addition, similarly to the first opening portion  73  described above, it is preferable that the fourth opening portion  76  overlap with at least a part of the fourth valve body  62 D as viewed in the +Y direction. In addition, it is preferable that the fourth opening portion  76  overlap with at least a part of the fourth pressure reception plate  66 D as viewed in the +Y direction. As described above, by providing the fourth opening portion  76  at a position that overlaps with the fourth valve body  62 D or a position that overlaps with the fourth pressure reception plate  66 D as viewed in the +Y direction, the movement of the fourth valve body  62 D can be stabilized when the fourth flexible film  63 D is pressed from the outside of the cover  70  via the fourth opening portion  76 . Therefore, the forcible valve opening of the fourth valve unit  60 D can be stably performed. 
     A relay substrate  51  is fixed to each of the surfaces of the flow path member  50  in the +X direction and −X direction. The relay substrate  51  is formed by a rigid substrate, and is provided independently for each liquid ejecting section  20 . That is, in the present embodiment, two relay substrates  51  are fixed side by side along the X axis on the surface of the flow path member  50  in the +Y direction. In addition, the two relay substrates  51  are fixed side by side along the X axis on the surface of the flow path member  50  in the −Y direction. Of course, the two relay substrates  51  provided on each of the surfaces in the +Y direction and the −Y direction may be used as one common relay substrate  51  that is continuous along the X axis. 
     The wiring substrate  22  of each liquid ejecting section  20  is electrically coupled to each of such relay substrates  51 . That is, an end portion of the wiring substrate  22  on a side opposite to the liquid ejecting section  20  is derived to the outside from a side surface in the direction along the Y axis, and is electrically coupled to an end portion in the +Z direction of the relay substrate  51  fixed to the side surface of the flow path member  50  of the Y axis. 
     In addition, a convex portion  77  protruding in the −Z direction is provided on the surface of the cover  70  in the −Z direction. The convex portion  77  is continuously provided along the X axis. A coupling substrate  78  is fixed to each of the surfaces of the convex portion  77  in the +Y direction and −Y direction. The coupling substrate  78  is formed by a rigid substrate, and two coupling substrates  78  are provided, one in each of the +Y direction and the −Y direction of the convex portion  77 . Each of the coupling substrates  78  is provided with two connectors  78   a  to which each of two wiring members  52  is coupled and a connector  78   b  to which a wiring from the outside (not shown) is coupled, and various signals, such as a printing signal, are supplied from the outside via the connector  78   b.  Such a coupling substrate  78  and a relay substrate  51  are electrically coupled via the wiring member  52 . As the wiring member  52 , a flexible sheet-like member, for example, a so-called flexible wiring, such as a COF substrate, FFC, or FPC, is used. The wiring member  52  is provided independently for each relay substrate  51 . That is, the wiring members  52  are arranged side by side along the X axis on the surface of the cover  70  in the +Y direction. In addition, the wiring members  52  are arranged side by side along the X axis on the surface of the cover  70  in the −Y direction. Here, among the wiring members  52 , the wiring member  52  disposed at a position that overlaps with the first valve unit  60 A as viewed in the +Y direction is referred to as a first wiring member  52 A. In addition, the wiring member  52  disposed at a position that overlaps with the second valve unit  60 B as viewed in the −Y direction is referred to as a second wiring member  52 B. Similarly, the wiring member  52  disposed at a position that overlaps with the third valve unit  60 C as viewed in the +Y direction is referred to as a third wiring member  52 C, and the wiring member  52  disposed at a position that overlaps with the fourth valve unit  60 D as viewed in −Y direction is referred to as a fourth wiring member  52 D. Moreover, the first wiring member  52 A is provided on the side opposite to the first outer surface  632 A of the first valve unit  60 A in the cover  70  in the −Y direction. In addition, the second wiring member  52 B is provided on the side opposite to the second outer surface  632 B of the second valve unit  60 B in the cover  70  in the +Y direction. Similarly, the third wiring member  52 C is provided on the side opposite to the third outer surface  632 C of the third valve unit  60 C in the cover  70  in the −Y direction, and the fourth wiring member  52 D is provided on the side opposite to the fourth outer surface  632 D of the fourth valve unit  60 D in the cover  70  in the +Y direction. It should be noted that, in the present embodiment, the first wiring member  52 A and the first outer surface  632 A are disposed at overlapping positions as viewed in the +Y direction. In addition, the second wiring member  52 B and the second outer surface  632 B are disposed at overlapping positions as viewed in the −Y direction. In addition, the third wiring member  52 C and the third outer surface  632 C are disposed at overlapping positions as viewed in the +Y direction. Further, the fourth wiring member  52 D and the fourth outer surface  632 D are disposed at overlapping positions as viewed in the −Y direction. It should be noted that each wiring member  52  is disposed at a position that does not block the openings of the first opening portion  73 , the second opening portion  74 , the third opening portion  75 , and the fourth opening portion  76 . 
     In this way, the wiring member  52  is provided on the outside of the cover  70 , that is, on the side surfaces in the +Y direction and the −Y direction, so that each valve unit  60  is disposed such that the outer surface  632  of the flexible film  63  faces the opposite side of the wiring member  52  in the Y axis. That is, since the first wiring member  52 A is positioned in the −Y direction with respect to the first valve unit  60 A, the first valve unit  60 A is disposed such that the first outer surface  632 A of the first flexible film  63 A faces the +Y direction opposite to the first wiring member  52 A. In other words, the first wiring member  52 A is provided on a side opposite to the first outer surface  632 A with respect to the surface of the first valve unit  60 A opposite to the first outer surface  632 A. The same applies to the second valve unit  60 B, the third valve unit  60 C, and the fourth valve unit  60 D. In this way, by disposing the valve unit  60  such that the outer surface  632  of the flexible film  63  is on the side opposite to the wiring member  52 , it is possible to prevent the wiring member  52  from inhibiting the deformation of the flexible film  63 . In addition, by providing the wiring member  52  on the outside of the cover  70 , even when the outer surface  632  of the flexible film  63  of each valve unit  60  faces the center side of the recording head  10  in the +Y direction, the flexible film  63  can be pressed from the outside of the cover  70  via the first opening portion  73 , the second opening portion  74 , the third opening portion  75 , and the fourth opening portion  76  to forcibly open the valve unit  60 . 
     In addition, a flow path opening portion  79  for exposing the supply path  641  of each valve unit  60  is provided on the surface of the cover  70  in the −Z direction. An end portion of the valve unit  60  in which the supply path  641  is opened is provided in a protrusion portion protruding in the −Z direction, and the protrusion portion in which the supply path  641  is opened is inserted into the flow path opening portion  79  of the cover  70 . As a result, the supply member  2  can be coupled to the supply path  641  on the −Z direction side of the recording head  10 . 
     Here, an example of the pressing mechanism that forcibly opens the valve unit  60  will be described with reference to  FIG.  14   . It should be noted that  FIG.  14    is a cross-sectional view of the recording head  10  and the pressing mechanism  80  taken along the line XIV-XIV. In addition,  FIG.  14    shows a state in which the forcible valve opening is performed by the pressing mechanism  80 . 
     As shown in  FIG.  14   , the pressing mechanism  80  is separately provided on the outside of the cover  70  of the recording head  10 . In the present embodiment, two pressing mechanisms  80  are provided, one in each of the +Y direction and the −Y direction of the recording head  10 . In the following, the pressing mechanism  80  disposed in the +Y direction of the recording head  10  will be described. 
     The pressing mechanism  80  is constituted by, for example, a push solenoid, and moves a shaft  82  coupled to a plunger  81  by on/off control from the control unit  8  along the Y axis with respect to a frame member  83 . The frame member  83  is fixed to, for example, the support  3  or the apparatus main body  7 . The shaft  82  is bifurcated on a distal end side, and two distal ends of the shaft are disposed at positions facing the first outer surface  632 A exposed to the first opening portion  73  and the third outer surface  632 C exposed to the third opening portion  75 , respectively, on the −Y axis. In the pressing mechanism  80 , by moving the shaft  82  in the −Y direction with respect to the frame member  83 , the distal ends of the shaft  82  abut on the first outer surface  632 A and the third outer surface  632 C exposed to the first opening portion  73  and the third opening portion  75 , respectively, and the first flexible film  63 A and the third flexible film  63 C are pressed by the shaft  82  in the −Y direction and displaced. As a result, it is possible to forcibly open the first valve unit  60 A and the third valve unit  60 C at the same time. 
     It should be noted that, since the pressing mechanism  80  disposed in the −Y direction is the same as the pressing mechanism  80  disposed in the +Y direction, the overlapping description will be omitted. It is possible to forcibly open the second valve unit  60 B and the fourth valve unit  60 D at the same time by the pressing mechanism  80  disposed in the −Y direction. 
     In the present embodiment, since two valve units  60  can be forcibly opened by one pressing mechanism  80 , the configuration can be simplified, the cost can be reduced, and the size can be reduced, as compared with the configuration in which the pressing mechanism is provided for each of the valve units  60 . Of course, the pressing mechanism may be provided for each of the valve units  60 . 
     In addition, three recording heads  10  are arranged side by side along the X axis in one head unit  1 . Therefore, when the distal end of the shaft  82  is branched in accordance with the number of the valve units  60  to be forcibly opened, the valve units  60  provided in two or more of the plurality of the recording heads  10  can be forcibly opened at the same time by one pressing mechanism  80 . That is, in the present embodiment, it is possible to forcibly open at maximum six valve units  60  by one pressing mechanism  80 . 
     In addition, in the present embodiment, the second opening portion  74  and the third opening portion  75  are provided in the first partition wall  72 A and the second partition wall  72 B, and have a shape in which the opening areas in the direction along the Y axis are substantially the same. Therefore, the distal end of the shaft  82  can be moved toward the second flexible film  63 B and the third flexible film  63 C by being guided by the inner wall surfaces of the second opening portion  74  and the third opening portion  75 , so that the forcible valve opening by the distal end of the shaft  82  can be reliably performed. 
     It should be noted that, in the head unit  1  according to the present embodiment, two rows each having three recording heads  10  arranged side by side along the X axis are provided on the Y axis. Therefore, a gap between two recording heads  10  adjacent to each other in the direction along the Y axis is relatively small. Therefore, when pressing the flexible film  63  exposed toward the gap between the recording heads  10  adjacent to each other in the direction along the Y axis, the shaft  82  of the pressing mechanism  80  need only be derived in the +X direction or the −X direction of the gap. 
     In addition, in the present embodiment, the push solenoid is used as the pressing mechanism  80 , but the present disclosure is not particularly limited to this, and an eccentric cam and a drive motor that rotates the eccentric cam may be used, and a hydraulic pump or the like may be used. 
     In addition, in the present embodiment, one pressing mechanism  80  forcibly opens two valve units  60  of one recording head  10  at the same time, but the present disclosure is not particularly limited to this, and one pressing mechanism  80  may forcibly open four valve units  60  of one recording head  10 . For example, the shafts  82  may be provided at both end portions of the plunger  81 , one shaft  82  may forcibly open two valve units  60  by moving the plunger  81  in the −Y direction the other shaft  82  may forcibly open two valve units  60  by moving the plunger  81  in the +Y direction. In addition, one pressing mechanism may forcibly open the four valve units  60  at the same time by combining gears and the like. 
     In addition, in the present embodiment, the pressing mechanism  80  is provided, but the present disclosure is not particularly limited to this, and an operator may forcibly open the valve by using a finger, a pin, or the like. Since the first opening portion  73  or the fourth opening portion  76  has a larger area than the second opening portion  74  or the third opening portion  75 , the first opening portion  73  or the fourth opening portion  76  can easily pass a finger, and it is easy to directly press the first flexible film  63 A and the fourth flexible film  63 D with a finger. 
     As described above, the recording head  10 , which is the liquid ejecting head according to the present embodiment, includes the liquid ejecting section  20  that ejects the ink, which is the liquid, the first valve unit  60 A that adjusts the pressure of the ink to be supplied to the liquid ejecting section  20 , and the cover  70  constituting the housing that accommodates the liquid ejecting section  20  and the first valve unit  60 A. In addition, the first valve unit  60 A has the first flow path  64 A that communicates with the liquid ejecting section  20 , and the first flexible film  63 A that has the first inner surface  631 A defining a part of the first flow path  64 A and the first outer surface  632 A being opposite to the first inner surface  631 A and being in contact with the atmosphere, and is displaceable in the −Y direction, which is the first direction, from the first outer surface  632 A toward the first inner surface  631 A and in the +Y direction, which is the second direction, opposite to the −Y direction. In addition, the first valve unit  60 A includes the first valve body  62 A that is moved between the opening position at which the first flow path  64 A is opened and the closing position at which the first flow path  64 A is closed, due to the displacement of the first flexible film  63 A. The cover  70  has the first opening portion  73  formed at the position facing at least a part of the first outer surface  632 A. 
     In this way, since the first outer surface  632 A is exposed to the outside by the first opening portion  73  formed in the cover  70 , the first flexible film  63 A can be operated from the outside of the recording head  10 . Therefore, it is not necessary to provide the pressing mechanism or the like that operates the first flexible film  63 A inside the recording head  10 , and the size of the recording head  10  can be reduced and the structure thereof can be simplified. In addition, since the first flexible film  63 A can be easily operated from the outside of the recording head  10  via the first opening portion  73 , it is possible to cause the forcible displacement due to the external force regardless of the differential pressure between the first inner surface  631 A and the first outer surface  632 A of the first flexible film  63 A, and it is possible to move the first valve body  62 A to the opening position to perform the forcible valve opening. 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the first opening portion  73  overlap with at least a part of the first valve body  62 A as viewed in the −Y direction, which is the first direction. According to this, when the first flexible film  63 A is pressed in the −Y direction for the forcible valve opening, the movement of the valve body  62  in the −Y direction can be stabilized. Therefore, it is possible to perform the stable forcible valve opening. 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the first valve unit  60 A include the first pressure reception plate  66 A, which is the pressure reception plate  66 , that has a higher Young&#39;s modulus than the first flexible film  63 A, is provided on the first inner surface  631 A of the first flexible film  63 A, and comes into contact with the distal end of the first valve body  62 A when the first valve body  62 A is positioned at the opening position, and the first opening portion  73  overlap with at least a part of the first pressure reception plate  66 A as viewed in the −Y direction, which is the first direction. According to this, when the first flexible film  63 A is pressed in the −Y direction for the forcible valve opening, the first pressure reception plate  66 A can be pressed, and the movement of the first valve body  62 A that is moved by the first pressure reception plate  66 A can be stabilized. Therefore, it is possible to perform the stable forcible valve opening. 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the gap t 1  between the portion facing the first outer surface  632 A at a position different from the first opening portion  73  on the inner wall surface  71   a  of the cover  70  constituting the housing, and the first outer surface  632 A be smaller than the dimension W 1  of the first valve unit  60 A in the −Y direction, which is the first direction. According to this, the size of the recording head  10  can be reduced in the −Y direction. It should be noted that, it is further preferable that the gap t 1  be smaller than ½ of the dimension W 1  of the first valve unit  60 A. 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the gap t 1  between the portion facing the first outer surface  632 A at a position different from the first opening portion  73  on the inner wall surface  71   a  of the cover  70  constituting the housing, and the first outer surface  632 A be smaller than the maximum displacement amount D 1  of the first flexible film  63 A in the −Y direction, which is the first direction. According to this, the size of the recording head  10  can be reduced in the −Y direction. 
     In addition, the recording head  10  according to the present embodiment further includes the second valve unit  60 B that is disposed in the cover  70  constituting the housing, and adjusts the pressure of the ink, which is the liquid, to be supplied to the liquid ejecting section  20 . In addition, the second valve unit  60 B has the second flow path  64 B that communicates with the liquid ejecting section  20 , and the second flexible film  63 B that has the second inner surface  631 B defining a part of the second flow path  64 B and the second outer surface  632 B being opposite to the second inner surface  631 B and being in contact with the atmosphere, and is displaceable in the +Y direction, which is the second direction, from the second outer surface  632 B toward the second inner surface  631 B and in the −Y direction, which is the first direction. In addition, the second valve unit  60 B includes the second valve body  62 B that is moved between the opening position at which the second flow path  64 B is opened and the closing position at which the second flow path  64 B is closed, due to the displacement of the second flexible film  63 B. The second valve unit  60 B is positioned to deviate from the first valve unit  60 A in the +Y direction, and the +Z direction or the +Y direction, which is the third direction orthogonal to the −Y direction, to overlap with a part of the first valve unit  60 A as viewed in the −Y direction. In addition, at least a part of the first outer surface  632 A does not overlap with the second valve unit  60 B as viewed in the −Y direction. In addition, at least a part of the second outer surface  632 B does not overlap with the first valve unit  60 A as viewed in the +Y direction. In addition, it is preferable that the cover  70  constituting the housing have the second opening portion  74  formed at a position facing at least a part of the second outer surface  632 B. 
     As described above, even when the recording head  10  is provided with the plurality of valve units  60  and the outer surfaces  632  of the plurality of valve units  60  are disposed to face each other, since at least a part of the outer surface  632  of the valve unit  60  is disposed not to overlap with other valve units  60 , it is possible to perform the forcible valve opening via the first opening portion  73  and the second opening portion  74 . It should be noted that the outer surfaces  632  of the plurality of valve units  60  may be disposed facing the outside and not to face each other. 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the third direction be the +X direction orthogonal to the +Z direction, which is the ejection direction, in which the liquid ejecting section  20  ejects the ink, which is the liquid. According to this, it is possible to suppress the increase in the size of the recording head  10  in the +Z direction and to reduce the size thereof in the +Z direction. 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the first valve unit  60 A and the second valve unit  60 B be disposed at the same position in the +Z direction, which is the ejection direction. According to this, the size of the recording head  10  can be reduced in the +Z direction. 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the distance L 1  from the opening at one end of the first opening portion  73  to the opening at the other end thereof be shorter than the distance L 2  from the opening at one end of the second opening portion  74  to the opening at the other end thereof. By forming the cover  70  in a shape along the disposition of the plurality of valve units  60 , the distance L 1  of the first opening portion  73  can be made shorter than the distance L 2  of the second opening portion  74 . Therefore, the size of the cover  70  can be reduced. 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the area of the first opening portion  73  be larger than the area of the second opening portion  74 . By making the area of the first opening portion  73  larger than the area of the second opening portion  74 , it is easy to press the first flexible film  63 A via the first opening portion  73 . 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the gap t 1  between the portion facing the first outer surface  632 A at a position different from the first opening portion  73  on the inner wall surface  71   a  of the cover  70  constituting the housing, and the first outer surface  632 A be narrower than the interval t 2  between of the first valve unit  60 A and the second valve unit  60 B in the −Y direction, which is the first direction. According to this, the size of the recording head  10  can be reduced in the −Y direction. 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the first outer surface  632 A and the second valve unit  60 B partially overlap with each other as viewed in the −Y direction, which is the first direction. According to this, the size of the recording head  10  can be reduced in the +X direction. 
     In addition, it is preferable that the recording head  10  according to the present embodiment include the first wiring member  52 A that is provided on a side opposite to the first outer surface  632 A with respect to a surface of the first valve unit  60 A opposite to the first outer surface  632 A, and is coupled to the liquid ejecting section  20 , and the second wiring member  52 B that is provided on a side opposite to the second outer surface  632 B with respect to a surface of the second valve unit  60 B opposite to the second outer surface  632 B, and is coupled to the liquid ejecting section  20 . In the disposition in which the wiring member  52  is drawn around the outside of the region in which the valve unit  60  is provided, it is necessary to make the flexible film  63  of the valve unit  60  face to the inside of the recording head  10 . Even in the configuration in which the flexible film  63  faces the inside of the recording head  10  in this way, the valve unit  60  can be forcibly opened by operating the flexible film  63  from the outside by the first opening portion  73  and the second opening portion  74 . 
     In addition, the recording head  10  according to the present embodiment further includes the third valve unit  60 C that is disposed in the cover  70  constituting the housing, and adjusts the pressure of the ink, which is the liquid, to be supplied to the liquid ejecting section  20 . It is preferable that the third valve unit  60 C be disposed in the +Z direction or the +X direction, which is the third direction, with respect to the first valve unit  60 A and be disposed to overlap with a part of the second valve unit  60 B as viewed in the +Y direction, which is the second direction, and the second opening portion  74  be provided between the first valve unit  60 A and the third valve unit  60 C. Even when the first valve unit  60 A, the second valve unit  60 B, and the third valve unit  60 C are disposed as described above, the second opening portion  74  can be provided between the first valve unit  60 A and the third valve unit  60 C. Moreover, the second valve unit  60 B can be forcibly opened by operating the second flexible film  63 B from the outside of the housing via the second opening portion  74 . 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the cover  70  constituting the housing have the first partition wall  72 A, which is the partition wall, that partitions the first valve unit  60 A and the third valve unit  60 C, and the second opening portion  74  be formed to penetrate the first partition wall  72 A in the −Y direction, which is the first direction. The shaft  82  that operates the second flexible film  63 B can be guided by the inner wall surface of the second opening portion  74 , and the second valve unit  60 B can be reliably forcibly opened. 
     In addition, in the recording head  10  according to the present embodiment, it is preferable that the second flexible film  63 B overlap with both the first valve unit  60 A and the third valve unit  60 C as viewed in the +Y direction, which is the second direction. According to this, the size of the recording head  10  can be reduced in the +X direction. 
     In addition, the ink jet type recording apparatus I, which is an example of the liquid ejecting apparatus according to the present embodiment, includes the recording head  10  which is an example of the liquid ejecting head described above, and the liquid storage section  4  that stores the ink, which is the liquid, to be supplied to the recording head  10 . As described above, it is not necessary to provide the pressing mechanism or the like that operates the first flexible film  63 A inside the recording head  10 , and the size of the recording head  10  can be reduced and the structure thereof can be simplified. Therefore, the size of the ink jet type recording apparatus I including the recording head  10  can be reduced and the structure thereof can be simplified. 
     Other Embodiments 
     One embodiment of the present disclosure has been described above, but the basic configuration of the present disclosure is not limited to the above. 
     For example, in the first embodiment described above, the configuration has been described in which the relay substrate  51  and the wiring member  52  are exposed to the side surfaces of the flow path member  50  and the cover  70 , but the present disclosure is not limited to this, and wiring covers that cover the relay substrate  51  and the wiring member  52 , respectively, may be provided on both sides of the cover  70  in the +Y direction and the −Y direction. When the wiring cover is provided, the communication holes that communicate with the first opening portion  73 , the second opening portion  74 , the third opening portion  75 , and the fourth opening portion  76  are provided on the wiring cover, so that the flexible film  63  of each valve unit  60  can be exposed to the outside, and the flexible film  63  can be operated from the outside of the wiring cover and forcibly opened. 
     In addition, the valve unit  60  may be provided with a flow path or the like for collecting the ink that has not been ejected from the nozzle  21  out of the ink supplied to the liquid ejecting section  20 . That is, the ink may be circulated between the liquid storage section  4  and the liquid ejecting section  20 . 
     In addition, the valve unit  60  may be provided with a filter that removes foreign substances, such as dust or air bubbles, contained in the ink flowing through the valve unit flow path  64 . 
     In addition, in the first embodiment described above, the third direction is the +X direction, but the present disclosure is not particularly limited to this. Since the third direction need only be the direction orthogonal to the −Y direction, which is the first direction, for example, the third direction may be the +Z direction. That is, the second valve unit  60 B may be disposed at a position deviating from the first valve unit  60 A in the +Y direction and the +Z direction to partially overlap with the first valve unit  60 A as viewed in the −Y direction. Even in this case, since the first flexible film  63 A can be pressed in the −Y direction, which is the first direction, via the first opening portion  73 , the first valve unit  60 A can be forcibly opened. It should be noted that the same applies to the third valve unit  60 C and the fourth valve unit  60 D. 
     Further, the present disclosure is intended for a wide range of the liquid ejecting head in general, and can be applied to, for example, a recording head, such as various ink jet type recording heads used in image recording apparatuses, such as printers, a color material ejecting head used in the manufacture of a color filter of a liquid crystal display or the like, an electrode material ejecting head used for electrode formation of an organic EL display, a field emission display (FED), or the like, and a bioorganic matter ejecting head used for biochip manufacture. In addition, although the ink jet type recording apparatus has been described as an example of the liquid ejecting apparatus, the present disclosure can also be used for a liquid ejecting apparatus using the other liquid ejecting head described above.