Patent Publication Number: US-8523326-B2

Title: Liquid ejecting head and liquid ejecting apparatus

Description:
This application claims a priority to Japanese Patent Application No. 2011-246065 filed on Nov. 10, 2011 which is hereby expressly incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a liquid ejecting head such as an ink jet recording head and a liquid ejecting apparatus and, more specifically, to a liquid ejecting head including a holding member provided with a head unit configured to eject liquid from a nozzle, a wiring member configured to be electrically connected to pressure generating units, and a wiring substrate configured to supply drive signals to the pressure generating units through the wiring member, and a liquid ejecting apparatus. 
     2. Related Art 
     A liquid ejecting apparatus is an apparatus including a liquid ejecting head, and configured to eject various types of liquid from the liquid ejecting head. Examples of a liquid ejecting apparatus include image recording apparatuses such as ink jet printers and ink jet plotters. However, in recent years, liquid ejecting apparatuses have also been applied to various types of manufacturing apparatuses by taking advantage of property that an extremely small amount of liquid is dropped accurately on a predetermined position. For example, the invention can be applied to display manufacturing apparatuses configured to manufacture color filters such as liquid crystal displays, electrode forming apparatuses configured to form electrodes such as those of organic electro luminescence displays, FEDs (surface emitting displays), and chip manufacturing apparatuses configured to manufacture biochips (biochemical elements). A recording head for image recording apparatuses ejects liquid ink, and a color material ejecting head for display manufacturing apparatuses ejects liquid solutions of respective color materials of R (Red), G (Green), and B (Blue). An electrode material ejecting head for an electrode forming apparatuses ejects a liquid electrode material and a bioorganic substance ejecting head for a chip manufacturing apparatuses ejects a liquid solution of bioorganic substance. 
     There are various types of liquid ejecting heads as described above, and those employing a so-called on-demand system which is in widespread use include a series of liquid flow channels, provided in a plurality, extending from a common liquid chamber (also referred to as a reservoir or a manifold) via pressure chambers to nozzles so as to correspond to nozzles, and are configured, for example, to eject liquid droplets from the nozzles by using pressure variations generated in the liquid in the pressure chambers by driving pressure generating units such as piezoelectric elements or heat generating elements. 
     A supply flow channel to which liquid from a liquid supply source such as an ink cartridge is supplied communicates with the common liquid chamber. The supply flow channel is located at a center portion of the common liquid chamber in the longitudinal direction, and is configured in such a manner that the distance from a communicating point (introduction port) between the supply flow channel and the common liquid chamber to the pressure chamber located at the farthest position from the introduction port from among the respective pressure chambers communicating with the common liquid chamber is as small as possible (that is, the distance is approximately half the dimension of the common liquid chamber in the longitudinal direction) (for example, see JP-A-2010-023437 (FIG. 2, and so forth). Accordingly, pressures of ink supplied to the respective pressure chamber communicating the same common liquid chamber are prevented from becoming unbalanced. 
     Incidentally, examples of a liquid ejecting head of this type include a liquid ejecting head provided on a case member (holding member), the liquid ejecting head including a wiring substrate (printed board) configured to receive a drive signal from an apparatus body side and supply the received drive signal to the pressure generating units, and the drive signal is supplied from the wiring substrate to the respective pressure generating units through a wiring member having flexibility (hereinafter, referred to as a flexible cable) such as a COP (chip on film) or TCP (tape carrier package). The flexible cable has a configuration in which a conductive pattern is formed on a surface of, for example, a base film such as polyimide using copper foil or the like, and the conductive pattern is covered with resist. A terminal portion on one end of the flexible cable is connected to a terminal portion of the pressure generating unit, and a terminal portion on the other end is connected to a base terminal portion on the wiring substrate. 
     The flexible cable is wired in a limited space in a recording head (in the case member). In particular, in the configuration in which the supply flow channel is connected to the center portion of the common liquid chamber, wiring of the flexible cable that bypasses the supply flow channel or provision of a clearance hole configured to allow passage of the supply flow channel of the flexible cable is needed. In the former case, in a configuration in which the length of the flexible cable is fixed to a certain length because of a layout or the like of the conductive pattern, it is necessary to wire the flexible cable along the direction of the height of the case member in order to avoid interference with respect to the supply flow channel, and hence the case member is required to have a height that correspondingly depends on the length of the flexible cable. Therefore, there is a problem of an increase in the size of the recording head. In the latter case, when the clearance hole as described above is formed in the flexible cable, formation of a conductive pattern on the flexible cable that bypasses the clearance hole is necessary. Therefore, there is a problem of an increase in the size of the flexible cable and an increase in cost. In the same manner, in the latter configuration, formation of the clearance hole configured to allow passage of the supply flow channel in the wiring substrate is needed, and hence the cost is increased in association with increase in the size of the wiring substrate in this aspect as well. 
     SUMMARY 
     An advantage of some aspects of the invention is that there is provided a liquid ejecting head configured to be capable of having a reduced size of the head and a reduced cost, and a liquid ejecting apparatus having the same. 
     In order to achieve the above described object, there is provided a liquid ejecting head comprising: 
     a holding member (case  15 ), the holding member including: a head unit ( 16 ) including a nozzle forming surface (nozzle plate  23 ) formed with nozzles ( 28 ) arranged horizontally in a first direction; a pressure generating unit (piezoelectric elements  36 ) configured to cause pressure variations in a pressure chamber ( 32 ) communicating the nozzles; and a common liquid chamber ( 33 ) formed along the first direction and to which liquid common to a plurality of the pressure chambers is introduced, and configured to eject the liquid from the nozzles by driving the pressure generating unit; a wiring member (flexible cables  40 ) electrically connected at an end portion thereof to the pressure generating unit; a wiring substrate ( 30 ) electrically connected to the other end portion of the wiring member and configured to supply a drive signal to the pressure generating unit via the wiring member; a supply flow channel ( 14 ) configured to supply the liquid from a liquid supply source to the common liquid chamber, wherein the head unit is fixed to the holding member in a position in which the nozzle forming surface faces a first surface and the wiring substrate is arranged on a second surface side on the opposite side from the first surface of the head fixing portion, the supply flow channel communicates with the common liquid chamber at an end of the common liquid chamber in the first direction, and the wiring member is disposed inside the supply flow channel in the first direction in the interior of the holding member. 
     According to the invention, since the supply flow channels communicate with the common liquid chambers at the end portions of the common liquid chambers in the first direction, and the wiring member is disposed inside the supply flow channel in the first direction in the interior of the holding member, the wiring member may be wired by being bent as needed without causing the interference with the supply flow channel between the pressure generating unit and the wiring substrate or without providing clearance holes or the like to allow passage of the supply flow channel in the wiring member. Therefore, even when the entire length of the wiring member is determined to be constant, a wiring space in the height direction of the holding member can be reduced by wiring the wiring member in a bent state or by wiring obliquely with respect to the nozzle forming surface, which contributes to downsizing of the liquid ejecting head. Since the clearance hole or the like which allows passage of the supply flow channels does not have to be provided in the wiring member, the size of the wiring member may be reduced correspondingly, which contributes to downsizing of the liquid ejecting head. 
     Preferably, an opening portion on an inlet port side of the supply flow channel is formed on the outside of the wiring substrate in the first direction in the second surface side. 
     In this configuration, since the clearance hole which allows passage of the supply flow channels in the wiring substrate does not have to be provided, the size of the wiring substrate may be reduced correspondingly, which contributes to downsizing of the liquid ejecting head. 
     Furthermore, in the configuration as described above, preferably, the wiring substrate includes a substrate terminal portion on the first surface side in a state of being arranged on the second surface, and the substrate terminal portion and the other end terminal portion of the wiring member are electrically connected. 
     In this configuration, since the wiring substrate has a configuration in which the substrate terminal portion is provided on the first surface side in the state in which the wiring substrate is arranged on the on the second surface and the substrate terminal portions and the other end terminal portions of the wiring member are electrically connected, though holes for allowing insertion of the wiring member do not have to be provided in the wiring substrate, so that the size of the wiring substrate may be reduced correspondingly. Accordingly, contribution to further downsizing of the liquid ejecting head is made. 
     The liquid ejecting apparatus includes the liquid ejecting head according to any one of the liquid ejecting head configured as described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  illustrates a perspective view for explaining a configuration of a printer. 
         FIG. 2  illustrates a cross-sectional view of a recording head in the direction orthogonal to a nozzle row (second direction). 
         FIG. 3  illustrates a cross-sectional view of the recording head in the direction of the nozzle row (first direction). 
         FIG. 4  illustrates a bottom view of the recording head. 
         FIG. 5  illustrates a top view of the recording head. 
         FIG. 6  illustrates a flexible cable. 
         FIG. 7  is a cross-sectional view of a head unit. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Referring now to attached drawings, embodiments of the invention will be described below. In the embodiments described below, various definitions are made as preferred embodiments of the invention. However, the scope of the invention is not limited to these modes unless otherwise specified in description given below to the effect of defining the invention. In the description given below, an ink jet printer (a type of liquid ejecting apparatus of the invention) including an ink jet recording head as a type of liquid ejecting head (hereinafter, referred to as a recording head) will be exemplified as the liquid ejecting apparatus of the invention. 
     Referring now to  FIG. 1 , a configuration of a printer  1  will be described. The printer  1  is an apparatus configured to perform recording of an image or the like by ejecting liquid ink to a surface of a recording medium  2  (a type of an object to be ejected) such as a recording sheet or the like. The printer  1  includes a recording head  3  configured to eject ink, a carriage  4  on which the recording head  3  is mounted, a carriage movement mechanism  5  configured to move the carriage  4  in a primary scanning direction, and a platen roller  6  configured to transport the recording medium  2  in a secondary scanning direction. The ink described above is a type of liquid of the invention, and is stored in an ink cartridge  7  as a liquid supply source. The ink cartridge  7  is demountably mounted on the recording head  3 . A configuration in which the ink cartridge  7  is arranged on the side of a main body of the printer  1  and ink is supplied from the ink cartridge  7  through an ink supply tube to the recording head  3  may also be employed. 
     The carriage movement mechanism  5  described above is provided with a timing belt  8 . Then, the timing belt  8  is driven by a pulse motor  9  such as a DC motor. Therefore, when the pulse motor  9  is activated, the carriage  4  is reciprocated in the primary scanning direction (the widthwise direction of the recording medium  2 ) while being guided by a guide rod  10  spanning across the printer  1 . 
       FIG. 2  illustrates a cross-sectional view of the recording head  3  in a direction orthogonal to nozzle rows (a second direction) and  FIG. 3  illustrates a cross-sectional view of the recording head  3  in the direction of the nozzle rows (a first direction).  FIG. 4  illustrates a bottom view of the recording head  3  and  FIG. 5  illustrates a top view of the recording head  3  (a state in which a needle holder  18  is not mounted). The recording head  3  of the embodiment includes a case  15  (corresponding to a holding member in the invention), a head unit  16 , a unit fixing plate  17 , and the needle holder  18 . 
     The needle holder  18  is a member provided with a plurality of ink introduction needles  20 , that extend upright from an upper surface side thereof, and is formed of, for example, synthetic resin. In the embodiment, a total of four of the ink introduction needles  20  are disposed horizontally on the upper surface of the needle holder  18  in a one to one correspondence with ink in each of the ink cartridges  7  for the respective colors. The ink introduction needles  20  are hollow needle shaped members to be inserted into the ink cartridges  7 , and introduce ink stored in the ink cartridges  7  from introduction holes (not illustrated) formed at distal ends thereof to the head unit  16  side through supply flow channels  14  in the case  15 . As illustrated in  FIG. 3 , the needle holder  18  is formed in the interior thereof with flat flow channels  13  each communicating with internal flow channels of the ink introduction needles  20 . The flat flow channels  13  each branch to the left and right in the first direction, which is the direction of the nozzle row below each of the ink introduction needles  20 , and extend to both ends in the same direction. Each of the flat flow channels  13  communicates with a corresponding one of the supply flow channels  14  in the case  15  respectively in a liquid tight manner via a packing  29  formed of a resilient material such as rubber or elastomer at both end portions in the direction of the nozzle rows. On a lower surface side of the needle holder  18 , a substrate housing  21  (see  FIG. 2 ) is formed in which a wiring substrate  30  arranged on a substrate mounting surface  46  (corresponding to a second surface of the invention), which is an upper surface of the case  15 , is housed. The needle holder  18  is fixed to the substrate mounting surface  46  side of the case  15  in a state in which the wiring substrate  30  is housed in the substrate housing  21 . 
     The case  15  is a hollow-box-shaped member formed of, for example, a synthetic resin. The case  15  includes a head fixing portion  15   a  to which the head unit  16  is fixed, and a substrate holding portion  15   b  in which the wiring substrate  30  is held and the needle holder  18  is fixed. In the interior of the head fixing portion  15   a  on a bottom surface (a first surface in the invention) side, a head unit housing space  19  is formed in which the head unit  16  is housed. In the interior of the head unit housing space  19  of the embodiment, a total of two of the head units  16  are housed horizontally in the second direction (the left and right direction in  FIG. 2 ) orthogonal to the direction of the nozzle rows. The respective head units  16  in the head unit housing space  19  are fixed to the metallic unit fixing plate  17  having two openings  17 ′ formed so as to correspond to the respective head units  16 . 
     In the interior of the head fixing portion  15   a  on the substrate holding portion  15   b  side (the substrate mounting surface  46  side), wiring spaces  22  are formed that communicate at lower ends thereof with the head unit housing space  19  and are open at upper ends thereof to the substrate mounting surface  46 . In the embodiment, a total of two of the wiring spaces  22  corresponding to the two head units  16  are provided in the head fixing portion  15   a  by being partitioned by a partitioning wall  22 ′. Part of an inner wall of each of the wiring spaces  22 , more specifically, a substantially upper half of the inner wall surface on the outside in the second direction is inclined upward toward the substrate mounting surface  46 . These surfaces function as guide surfaces  39  configured to guide flexible cables  40  toward wiring areas  49  on the substrate mounting surface  46  as described later. 
     The substrate holding portion  15   b  is a member formed integrally with the head fixing portion  15   a  on an upper surface side thereof. An upper surface of the substrate holding portion  15   b  corresponds to the substrate mounting surface  46  on which the wiring substrate  30  and the other end portions of the flexible cables  40  are placed. In plan view, the surface area of the substrate mounting surface  46  is larger than the surface area of the head fixing portion  15   a . A portion of the substrate holding portion  15   b  projecting sideward with respect to the head fixing portion  15   a  corresponds to a flange portion  47 . The wiring spaces  22  of the head fixing portion  15   a  are respectively open at a center portion of the substrate mounting surface  46 . As illustrated in  FIG. 5 , the wiring areas  49  where the other end portions of the flexible cables  40  drawn from the wiring spaces  22  are arranged are respectively partitioned on the outsides of the openings of the respective wiring spaces  22  in the second direction on the substrate mounting surface  46 . Positioning pins  51  are provided at both end portions of the wiring areas  49  in the first direction so as to project therefrom. In the embodiment, since the two wiring areas  49  are defined, a total of four of the positioning pins  51  are provided on the substrate mounting surface  46 . The positioning pins  51  are configured to set a relative position between the flexible cable  40  and the wiring substrate  30  on the substrate mounting surface  46 . 
     On the substrate mounting surface  46 , upstream ends of the supply flow channels  14  are open at both end portions of the openings of the respective wiring spaces  22  (or the wiring areas  49 ) in the first direction. As illustrated in  FIG. 3 , the respective supply flow channels  14  are elongated flow channels extending along the direction of the height of the case  15  from the substrate mounting surface  46  side to the head units  16  side in the interior of the case  15 . Lower ends of the supply flow channels  14  communicate with common liquid chambers  33  via ink introduction channels  43  of the head units  16 . In the embodiment, two of the supply flow channels  14  are provided for each common liquid chamber  33 . A pair of the supply flow channels  14  communicating with the same common liquid chamber  33  are formed on both sides with the wiring spaces  22  interposed therebetween in the first direction in the interior of the case  15 . Therefore, the respective supply flow channels  14  communicate with the common liquid chambers  33  at ends of the common liquid chambers  33  in the first direction. 
     As illustrated in  FIG. 4 , the flange portion  47  of the substrate holding portion  15   b  is formed with wiring openings  50  each having an elongated rectangular opening in a state of penetrating through the substrate holding portion  15   b  in the thickness direction. The wiring openings  50  are formed at positions corresponding to joint portions  60  which are at superposed positions at which substrate terminal portions  53  of the wiring substrate  30  and the other end side terminal portions  54  of the flexible cables  40  arranged so as to be positioned at predetermined positions on the substrate mounting surface  46  are superposed with each other. The dimensions of the wiring openings  50  are set to be slightly larger than those of the other end terminal portions  54  and the substrate terminal portions  53 . Accordingly, when the other end portions of the flexible cables  40  and the wiring substrate  30  are arranged on the substrate mounting surface  46  in the state of being positioned by the positioning pins  51 , the joint portions  60  face the interior of the wiring openings  50 . 
     The flexible cables  40  are each configured in such a manner that a drive IC  58  configured to control application of a drive voltage to a piezoelectric element  36  is mounted on a surface of a base film such as a polyimide film, and a conductive pattern to be connected to the drive IC  58  is formed of a copper film, and the conductive pattern and the drive IC  58  are covered with resist. At one end portion of each of the flexible cables  40 , a one-end side terminal portion (not illustrated) is formed to be in conductive contact with the piezoelectric element  36  and at the other end portion thereof, the other end terminal portion  54  (wiring end portion) is formed to be in conductive contact with the substrate terminal portion  53  of the wiring substrate  30 . At the other end portions of the flexible cables  40  at positions corresponding to the positioning pins  51  of the substrate mounting surface  46 , cable through holes  59  which allow insertion of the positioning pins  51  are formed (see  FIG. 5 ) at two positions. 
     The flexible cables  40  are housed in the wiring spaces  22  in a state in which one end portion thereof is connected to an element end portion of the piezoelectric element  36 . In other words, as illustrated in  FIG. 2 , the flexible cables  40  are drawn out from the head unit  16  into the wiring spaces  22  in a substantially vertical position with respect to a nozzle forming surface (nozzle plate  23 ). As described above, the wiring spaces  22  are formed between the supply flow channels  14  at both sides in the first direction in the case  15 . Therefore, the flexible cables  40  are disposed between the supply flow channels  14  without being interfered with by the supply flow channels  14 . In other words, since the supply flow channels  14  do not pass through the wiring spaces  22  because the supply flow channels  14  are formed on the both sides of the wiring spaces  22  in the first direction, the wiring spaces  22  can be used effectively for wiring the flexible cables  40 . The flexible cables  40  drawn out into the wiring spaces  22  are each bent at a midpoint (between one end portion and the other end portion thereof) in the wiring spaces  22 . Portions on the distal sides of the bent portion (the other end portion sides) take positions inclined with respect to the nozzle forming surface so as to extend along the guide surfaces  39  of the wiring spaces  22 . In this manner, by wiring the flexible cables  40  by bending the same, the height of the case  15  may be reduced, which contributes to decrease in the size of the entire recording head  3 . The other end portions of the flexible cables  40  are drawn out from the wiring spaces  22  along the guide surfaces  39  toward the substrate mounting surface  46 , and the positioning pins  51  are respectively inserted into the respective cable through holes  59 , and are arranged on the wiring areas  49  of the substrate mounting surface  46 . 
       FIG. 6  illustrates a plan view for explaining a configuration of the wiring substrate  30  and illustrates a surface on the substrate mounting surface  46  side of the wiring substrate  30 . The wiring substrate  30  is a substrate configured to receive a drive signal from the printer body, and is formed with a wiring pattern or the like for supplying the drive signal to the piezoelectric element  36  via the flexible cables  40 . The wiring substrate  30  is formed with the substrate terminal portions  53  which are in conductive contact with the other end terminal portions  54  of the flexible cables  40 , and includes a connector  55  for connection to the printer body side and other electronic components mounted thereon. On the wiring substrate  30  of the embodiment, two of the substrate terminal portions  53  are formed so as to correspond to the other end terminal portions  54  of the two flexible cables  40  arranged on the substrate mounting surface  46 . Wiring members such as a FFC (Flexible Flat Cable) are connected to the connector  55 , and the wiring substrate  30  is configured to receive the drive signal from the printer body side via the FFC. 
     On the wiring substrate  30 , a total of four substrate through holes  56  which allow insertion of the positioning pins  51  are formed at positions corresponding to the positioning pins  51  of the substrate mounting surface  46 . The wiring substrate  30  is arranged between openings of the supply flow channels  14  formed on both sides in the first direction on the substrate mounting surface  46  in a state in which a substrate terminal portion forming surface faces the substrate mounting surface  46  of the case  15 , the positioning pins  51  are inserted through the respective substrate through holes  56 , and other end portions  9   b  of the flexible cables  40  are interposed therebetween. Accordingly, the positions of the substrate terminal portions  53  and the other end terminal portions  54  of the flexible cables  40  on a flat surface match. The positions of superimposition of the terminal portions correspond to the joint portions  60 . 
       FIG. 7  illustrates a cross-sectional view showing an internal configuration of the head unit  16 . The head unit  16  of the embodiment basically includes the nozzle plate  23 , a flow channel substrate  24 , a common liquid chamber substrate  25 , and a compliance substrate  26 , and is fitted in a unit case  27  in a state in which these members are stacked. The nozzle plate  23  (a type of nozzle formed member) is a plate-like member having a plurality of nozzles  28  formed in rows at a pitch corresponding to a dot formation density. In this embodiment, each nozzle row is configured by forming  360  nozzles  28  at a pitch of 360 dpi. 
     The flow channel substrate  24  is formed of a thin resilient film  31  formed of silicon dioxide on an upper surface (the surface on the common liquid chamber substrate  25  side) by thermal oxidation. The flow channel substrate  24  is formed of a plurality of pressure chambers  32  defined by a plurality of partitioning walls by using an anisotropic etching process so as to correspond to the respective nozzles  28 . Outside the row of the pressure chambers  32  in the flow channel substrate  24 , communicating spaces  34  are formed which define parts of the common liquid chambers  33  as chambers to allow introduction of ink common to the respective pressure chambers  32 . The communicating spaces  34  communicate with the respective pressure chambers  32  via the ink introduction channels  43 . 
     On the resilient film  31  on the upper surface of the flow channel substrate  24 , the piezoelectric elements  36  are formed by stacking a metallic lower electrode film, a piezoelectric body layer formed of lead zirconate titanate (PZT), and a metallic upper electrode film in this order for the respective pressure chambers  32 . The piezoelectric elements  36  are piezoelectric elements of a so-called flexible mode, and are formed so as to cover upper portions of the pressure chambers  32 . Electrode wiring portions  48   a  and  48   b  extend over the resilient film  31  respectively from respective element electrodes of the piezoelectric elements  36 , and wiring terminals (not illustrated) provided at one end portions of the flexible cables  40  are electrically connected to portions corresponding to electrode terminals of the electrode wiring portions. The respective piezoelectric elements  36  are deformed when a drive voltage is applied between the upper electrode film and the lower electrode film through the flexible cables  40 . 
     Arranged on the flow channel substrate  24  formed with the respective piezoelectric elements  36  is the common liquid chamber substrate  25  having through spaces  37  penetrating therethrough in the thickness direction. The common liquid chamber substrate  25  is manufactured by using a silicone monocrystal substrate in the same manner as the flow channel substrate  24  and the nozzle plate  23 . The through spaces  37  on the common liquid chamber substrate  25  communicate with the communicating spaces  34  of the flow channel substrate  24  and define the parts of the common liquid chambers  33 . 
     The compliance substrate  26  is arranged on an upper surface side of the common liquid chamber substrate  25 . In areas of the compliance substrate  26  facing the through spaces  37  of the common liquid chamber substrate  25 , ink introduction ports  41  for supplying ink from the ink introduction needle  20  side to the common liquid chambers  33  are formed so as to penetrate through the direction of the thickness. Two of the ink introduction ports  41  are provided for each of the common liquid chambers  33 . A pair of the ink introduction ports  41  communicating with the same common liquid chamber  33  are formed at positions corresponding to both sides of the common liquid chambers  33  in the first direction. Areas of the compliance substrate  26  other than the ink introduction ports  41  of the areas facing the through spaces  37  are the flexible portions  42  formed to be thin, and the common liquid chambers  33  are defined and formed by sealing upper openings of the through spaces  37  by the flexible portions  42 . The flexible portions  42  function as compliance portions which absorb pressure variations of the ink in the common liquid chambers  33 . 
     The common liquid chambers  33  in the embodiment are spaces extending along the nozzle rows (first direction) for each of the nozzle rows, and ink common to the respective pressure chambers  32  belonging to the nozzle rows is introduced thereto. As described above, the common liquid chambers  33  communicate with the supply flow channels  14  of the case  15  via the ink introduction channels  43  at the both end portions in the first direction. Therefore, the ink introduced from the ink introduction channels  43  side to the common liquid chambers  33  flows toward the center portion from the both end sides in the first direction. As illustrated in  FIG. 3 , ceiling surfaces of the common liquid chambers  33  have a tapered shape inclining gradually downward (toward the nozzle forming surface) from the both end portions in the first direction respectively toward the center portion. In other words, the height of the flow channel in the common liquid chambers  33  is gradually reduced from the both end sides in the first direction toward the center side. Accordingly, the ink introduced into the common liquid chambers  33  flows smoothly from the both end portions to the center portion. Therefore, the pressure of ink supplied to the respective pressure chambers  32  communicating with the common liquid chambers  33  may be aligned as much as possible. 
     The unit case  27  is a member formed with the ink introduction channels  43  communicating with the ink introduction ports  41  for introducing ink introduced from the ink introduction needle  20  side toward the common liquid chambers  33 , and each formed with a depression for allowing swelling of the flexible portion  42  in areas opposing the flexible portion  42 . Two each of the ink introduction channels  43  are provided for each of the common liquid chambers  33 , and formed in the state of penetrating therethrough in the height direction of the unit case  27 . Upstream ends of the ink introduction channels  43  communicate with the supply flow channels  14  of the case  15 , and downstream ends thereof communicate with the common liquid chambers  33  via the ink introduction ports  41 . A pair of the ink introduction channels  43  communicating with the same common liquid chamber  33  are formed respectively at the positions corresponding to the both sides of the common liquid chamber  33  in the first direction. At a center portion of the unit case  27  (an area between the ink introduction channels  43  on the both sides in the first direction), a space  44  is formed so as to penetrate therethrough in the thickness direction, and one end of each of the flexible cables  40  is inserted into the space  44  and is electrically connected to an electrode wiring portion  48  of the piezoelectric elements  36 . 
     The nozzle plate  23 , the flow channel substrate  24 , the common liquid chamber substrate  25 , the compliance substrate  26 , and the unit case  27  are joined with respect to each other by being heated in the stacked state with an adhesive agent or a thermally adhesive film interposed therebetween. 
     The recording head  3  provided with the head units  16  configured as described above is mounted on the carriage  4  so that the nozzle row direction (the first direction) is aligned with the secondary scanning direction in a state in which the respective nozzle plates  23  face the platen. The head units  16  each take ink from the ink cartridge  7  to the common liquid chamber  33  side from the ink introduction port  41  through the ink introduction needle  20 , the flat flow channel  13 , the supply flow channels  14 , and the ink introduction channels  43 , and ink flow channels extending from the common liquid chambers  33  to the nozzles  28  are filled with ink. Then, pressure variations are caused in ink in the corresponding pressure chambers  32  by causing the piezoelectric elements  36  to be flexibly deformed by applying the drive voltage from the flexible cables  40  to the piezoelectric elements  36 , and ink is ejected from the nozzles  28  by using the pressure variations of ink. 
     Subsequently, a method of manufacturing the recording head  3  will be described. 
     The flexible cables  40  connected at one of the end portions thereof to the electrode wiring portions  48  of the piezoelectric elements  36  of the head units  16  are drawn out into the wiring spaces  22  in the substantially vertical position with respect to the nozzle forming surfaces from the head units  16 , and are bent at the midpoint in the interior of the wiring spaces  22 , while portions of the other ends on the distal side from the bent portion are drawn out from the wiring space  22  sides along the guide surfaces  39  to the substrate mounting surfaces  46 . Then, the flexible cables  40  are arranged on the wiring areas  49  of the substrate mounting surfaces  46  in a state of being positioned by the positioning pins  51  inserted into the respective cable through holes  59 , respectively. In this case, the surfaces of the other end portions of the flexible cables  40  where the other end terminal portions  54  are formed face the opposite side from the substrate mounting surface  46  (upward). 
     Subsequently, the wiring substrate  30  is stacked on the other end portions of the flexible cables  40  on the substrate mounting surface  46 . In this case, the wiring substrate  30  is mounted on the substrate mounting surface  46  by inserting the positioning pins  51  into the substrate through holes  56  and in a state in which the surface where the substrate terminal portions  53  are formed faces the substrate mounting surface  46  side, that is, the other end portions of the flexible cables  40  on the substrate mounting surface  46  in a state in which the other end portions of the flexible cables  40  are interposed therebetween. Accordingly, the other end terminal portions  54  and the substrate terminal portions  53  are overlapped in a state in which the relative positions between the respective terminals of the other end terminal portions  54  and the respective terminals of the substrate terminal portions  53  match. In this state, the joint portions  60  where the other end terminal portions  54  and the substrate terminal portions  53  are overlapped face into the wiring openings  50  provided on the substrate holding portion  15   b . Solder plating is applied in advance on at least one of the other end terminal portions  54  and the substrate terminal portions  53 . In the embodiment, the other end terminal portions  54  and the substrate terminal portions  53  are soldered and electrically joined by heating the joint portions  60  through the wiring openings  50  using a heat tool or the like. 
     As described above, in the recording head  3  of the invention, since the supply flow channels  14  communicate with the common liquid chambers  33  at the end portions of the common liquid chambers  33  in the first direction, and the flexible cables  40  are disposed inside the supply flow channels  14  in the first direction in the interior of the case  15 , the flexible cables  40  may be wired by being bent as needed without causing the interference with the supply flow channels  14  between the piezoelectric elements  36  and the wiring substrate  30  or without providing clearance holes or the like to allow passage of the supply flow channels  14  in the flexible cables  40 . Therefore, even when the entire length of the flexible cables  40  are determined to be constant, the wiring space in the height direction of the case  15  can be reduced by wiring the flexible cables  40  in a bent state or by wiring obliquely with respect to the nozzle forming surface, which contributes to downsizing of the recording head  3 . 
     As described above, since the clearance holes or the like which allow passage of the supply flow channels  14  does not have to be provided in the flexible cables  40 , the size of the flexible cables  40  may be reduced correspondingly, which contributes to downsizing of the recording head  3 . In the same manner, since the clearance holes or the like which allow passage of the supply flow channels  14  do not have to be provided on the wiring substrate  30  as well, the size of the wiring substrate  30  may be reduced correspondingly. 
     Also, since the recording head  3  of the embodiment has a configuration in which the substrate terminal portions  53  are provided on the nozzle forming surface side in a state in which the wiring substrate  30  is arranged on the substrate mounting surface  46  and the substrate terminal portions  53  and the other end terminal portions  54  of the flexible cables  40  are electrically connected, though holes for allowing insertion of the flexible cables  40  do not have to be provided in the wiring substrate  30 , so that the size of the wiring substrate  30  may be reduced correspondingly, which contributes to further downsizing of the recording head  3 . 
     In the recording head  3  of the embodiment, since two in total supply flow channels  14  communicate in parallel at both end portions in the first direction for each of the common liquid chambers  33 , pressure loss in the supply flow channels  14  may be reduced in comparison with a configuration in which one supply flow channel  14  communicate with one common liquid chamber  33 . In addition, the distance to the pressure chamber  32  located at the farthest position from the communicating portions of the common liquid chambers  33  (that is, the openings of the ink introduction channels  43  in the embodiment) with respect to the supply flow channels  14  becomes half the length of the common liquid chambers  33  in the first direction. Therefore, lowering of the pressure of ink supplied to the pressure chambers  32  may be inhibited. 
     The invention is not limited to the embodiments described above and various modifications may be made on the basis of description of claims. 
     For example, in the embodiment, an example in which two each of the supply flow channels  14  and the ink introduction channels  43  communicating therewith and so forth are provided at positions corresponding to the both sides of the common liquid chambers  33  in the first direction has been exemplified, the invention is not limited thereto. A configuration in which one each of the supply flow channel  14  and the ink introduction channel  43  communicating thereto are provided for each of the common liquid chambers  33 , and the supply flow channels  14  communicate at one end portion of the common liquid chambers  33  in the first direction may be employed. 
     In the description given above, a so-called flexural oscillation type piezoelectric element has been exemplified as the pressure generating unit in the invention. However, the invention is not limited thereto, and the invention may be applied to a configuration in which a so-called electrostatic type actuator which displaces part of the pressure chamber by an electrostatic force, or other types of pressure generating units such as heat generating element or the like which causes pressure variations in the pressure chamber by air bubbles caused by heating. 
     In the description given above, the ink jet recording head  3  as a type of liquid ejecting head is exemplified, the invention may also be applied to other liquid ejecting heads employing a configuration including a holding member provided with a head unit configured to eject liquid from a nozzle, a wiring member configured to be electrically connected to a pressure generating unit, and a wiring substrate configured to supply a drive signal to the pressure generating unit through the wiring member. For example, the invention may be applied to a color material ejecting head used for manufacturing color filters such as liquid crystal display or the like, an electrode ejecting head used for forming electrode such as an organic EL (Electro Luminescence) display, an FED (surface light-emitting display), a bioorganic substance ejecting head used for manufacturing a biochip, and so forth.