Patent Publication Number: US-9840076-B2

Title: Liquid ejecting head and liquid ejecting apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2014-159063 filed on Aug. 4, 2014 and Japanese Patent Application No. 2014-159064 filed on Aug. 4, 2014. The entire disclosures of Japanese Patent Application Nos. 2014-159063 and 2014-159064 are hereby incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a technique for ejecting liquid such as ink. 
     2. Related Art 
     Various techniques for ejecting liquid such as ink onto a medium such as printing paper are proposed in the related art. For example, JP-A-2013-103429 discloses a liquid ejecting head which causes ink inside a pressure chamber to be ejected from a nozzle by driving each of a plurality of piezoelectric elements that are arranged in two rows of a first row and a second row. A plurality of electrodes (connection terminals) for electrically connecting the plurality of piezoelectric elements to wirings on a flexible wiring board (flexible cable) are formed in a region between the first row and the second row (hereinafter referred to as a “mounting region”). 
     It is possible to arrange the plurality of piezoelectric elements in various aspects according to a nozzle position that corresponds to each piezoelectric element. Meanwhile, each of the plurality of electrodes within the mounting region are formed at a position corresponding to each piezoelectric element. Accordingly, for example, if a configuration is assumed where the position in the arrangement direction of the piezoelectric elements is made different for the first row and the second row, in a region in which the first row and the second row of the piezoelectric elements overlap with one another in the mounting region, there is a configuration in which electrodes that are connected to each of the piezoelectric elements of the first row and electrodes that are connected to each of the piezoelectric elements of the second row are mixed, in a region at an end section side of the mounting region, electrodes that are connected to each of the piezoelectric elements of only one of the first row or the second row are present, and so the density of the electrodes is different in each region within the mounting region. 
     However, it is possible for various problems caused by the densities of the electrodes within the mounting region to occur. For example, the degree of flow of an adhesive differs according to the densities of the electrodes within the mounting region in the process of mounting components of wiring boards or the like using an adhesive within the mounting region, and it is possible for a problem resulting in adhesion failure or the like to occur. Alternatively, for example, in a case where a liquid ejecting head is heated in the manufacturing process, it is possible that biasing in heat distribution within the mounting region occurs according to the densities of the electrodes within the mounting region and non-uniformity of characteristics of the components formed hereafter is caused. 
     SUMMARY 
     An advantage of some aspects of the invention is to uniformize the densities of electrodes within the mounting region. 
     According to an aspect of the invention, there is provided a liquid ejecting head including: a plurality of driving elements which cause liquid to be ejected from nozzles by imparting pressure to a pressure chamber in which the liquid is filled, the plurality of driving elements including a plurality of first driving elements which are arranged along a first direction and a plurality of second driving electrodes which are arranged along the first direction at the opposite side to the plurality of first driving elements with a mounting region, in which a mounting component is installed, interposed therebetween; and a plurality of electrodes which are formed in the mounting region so as to extend along the second direction which intersects with the first direction, in which the plurality of electrodes include: a plurality of first electrodes which are arranged along the first direction in a first region within the mounting region and are electrically connected to the plurality of first driving elements; a plurality of second electrodes which are arranged along the first direction across the first region within the mounting region and a second region within the mounting region which is positioned at one side in the first direction viewed from the first region, and are electrically connected to the plurality of second driving elements; and a third electrode which does not contribute to ejection of the liquid and is formed between each of the second electrodes that are adjacent to one another along the first direction in the second region. In the above aspect, in the configuration where the first electrodes and the second electrodes are formed in the first region and the second electrodes are formed in the second region of the mounting region, the third electrodes that do not contribute to ejection of liquid are formed between each of the second electrodes which are adjacent to one another along the first direction within the second region. Accordingly, in comparison to the configuration where the third electrodes are not formed in the second region, the difference in density of the electrodes between the first region and the second region is reduced. That is, it is possible to uniformize density of the electrodes within the mounting region. According to a configuration where the numerical values of a pitch where the first electrodes and the second electrodes are arranged within the first region and a pitch where the second electrodes and third electrodes are arranged in the second region are equal, the effect in which it is possible to uniformize the densities of the electrodes within the mounting region is particularly remarkable. 
     Here, the “third electrodes do not contribute to ejection of liquid” has the meaning of, for example, so-called dummy electrodes which include electrodes that are not electrically connected to the driving elements, electrodes that are electrically connected to an ineffective driving element that does not contribute to ejection of liquid, and the like. The ineffective driving element is the same as a component configured by an effective driving element that contributes to ejection of liquid where a section is defective (that is, an element which does not actually operate) or a driving element where the structure of the driving element is effective (accordingly, actually operating due to supply of an electrical signal), but includes a driving element which is arranged corresponding to a flow path that reaches externally that is blocked at an arbitrary location (for example, a flow path where the nozzle furthest downstream is blocked or a flow path where a middle location is blocked). 
     Here, based on the configuration where a flexible wiring board on which a plurality of connection terminals, which are electrically connected to the plurality of first electrodes and plurality of second electrodes, are formed is set as an electric wiring (e.g. a mounting component) and fixed using an adhesive, in a case where the densities of the electrodes in the first region and the second region are different, it is possible that the optimal coating amount and flow amount of the adhesive are different in the first region and the second region, therefore it is possible that a problem such as insufficient adhesive strength or positional error of the wiring board manifests. Accordingly, the invention in which it is possible to uniformize densities of the electrodes within the mounting region is particularly effective in a case where the flexible wiring board is set as the mounting component and is fixed using an adhesive. In particular, in a configuration provided with a structure that includes a first wall surface positioned between the mounting region and a plurality of first driving elements and a second wall surface positioned between the mounting region and the second driving elements, it is possible for an error to occur at a position on the wiring board due to stress from the adhesive resulting from an excess of adhesive blocking the first wall surface and the second wall surface. The invention where it is possible to uniformize densities of the electrodes within the mounting region is particularly preferable in a configuration where a structure including the first wall surface and the second wall surface is installed. 
     In the aspect of the invention, a plurality of third electrodes are arranged at a first pitch along the first direction at an opposite side to the first region in the second region. In the aspect above, in addition to the third electrodes being formed in a region where the second electrodes are formed in the second region, a plurality of electrodes are arranged at the first pitch at an opposite side to the first region in the second region. Accordingly, it is advantageous in that it is possible to uniformize densities of electrodes across a wide range including a region where the second electrodes are not present in the second region. 
     In a configuration where each of the plurality of driving elements includes a first driving electrode, a piezoelectric body which is formed on an upper surface of the first driving electrode in a process including heat treatment, and a second driving electrode which is formed on an upper surface of the piezoelectric body, the first electrode is electrically connected to the first driving electrode of the first driving element, and the second electrode is electrically connected to the first driving electrode of the second driving element, in a heat treatment process in which a piezoelectric body is formed, it is possible that biasing in heat distribution occurs according to the presence or absence of the first electrodes and that a problem such as film formation failure of the piezoelectric body is caused. Considering the circumstances above, the liquid ejecting head according to the aspect of the invention includes fourth electrodes that are formed on the same layer as the first driving electrodes at an opposite side to another end section that interposes one end section in an array of the plurality of first driving elements. In the above aspect, since the fourth electrodes are formed on the same layer as the first driving electrodes at the opposite side to the other end section that interposes the one end section in an array of the plurality of first driving elements, biasing in heat distribution between the region in which the first driving elements are arranged and another region is reduced. Accordingly, it is possible to eliminate the problem such as film formation failure of a piezoelectric body of each driving element. As a result of the above, an interval between the first driving electrode of the first driving element and the first driving electrode of the second driving element is particularly remarkable in a wide configuration in comparison to the range in which the fourth electrodes are distributed along the first direction. 
     In the aspect of the invention, the range in which the first electrodes are present along the second direction and the range in which the second electrodes are present along the second direction overlap with one another in the second direction. In the above aspect, the range in which the first electrodes are present along the second direction and the range in which the second electrodes are present along the second direction overlap, therefore in a simple process in which mounting components are installed within the range of overlapping, it is possible to connect the first electrodes and the second electrodes with respect to the mounting components. 
     In the aspect of the invention, a virtual line that links a nozzle corresponding to a first driving element which is positioned at an end section at one side in the first direction among the plurality of first driving elements and a nozzle corresponding to a second driving element which is positioned at an end section at one side in the first direction among the plurality of second driving elements is inclined at an angle within the range of 30° to 60° inclusive in the first direction (further preferably, within the range of 30° to 40° inclusive, or 50° to 60° inclusive). In the above aspect, since the virtual line and the first direction are inclined to one another, in comparison, for example, to a configuration where a plurality of nozzles are arranged in a direction perpendicular to the first direction, it is possible to increase the dot density (resolution) in the direction. 
     A liquid ejecting apparatus according to another aspect of the invention includes the liquid ejecting head according to each of the above aspects. A printing apparatus which ejects ink is a preferred example of the liquid ejecting head, but the applications of the liquid ejecting apparatus according to the invention are not limited thereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a configuration diagram of a printing apparatus according to a first embodiment of the invention. 
         FIG. 2  is a planar diagram of a liquid ejecting module. 
         FIG. 3  is an exploded perspective diagram of a liquid ejecting unit. 
         FIG. 4  is explanatory diagram of an array of a plurality of nozzles. 
         FIG. 5  is sectional diagram of a liquid ejecting head. 
         FIG. 6  is sectional diagram of the liquid ejecting head which is enlarged in the vicinity of a piezoelectric element. 
         FIG. 7  is an explanatory diagram of the liquid ejecting head which is focused on a mounting region. 
         FIG. 8  is an explanatory diagram of a liquid ejecting head according to a second embodiment. 
         FIG. 9  is an explanatory diagram of a liquid ejecting head according to a third embodiment. 
         FIG. 10  is an explanatory diagram of a liquid ejecting head according to a fourth embodiment. 
         FIG. 11  is an explanatory diagram of an array of a plurality of nozzles according to a modification example. 
         FIG. 12  is an explanatory diagram of a pitch in an array of a plurality of electrodes. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     First Embodiment 
       FIG. 1  is a partial configuration diagram of an ink jet type printing apparatus  10  according to a first embodiment of the invention. The printing apparatus  10  of the first embodiment is a liquid ejecting apparatus which ejects ink, which is an exemplification of a liquid, onto a medium  12  (ejection target) such as printing paper and includes a control device  22 , a transport mechanism  24 , and a liquid ejecting module  26 . A liquid container (cartridge)  14  which retains ink of a plurality of colors is mounted in the printing apparatus  10 . In the first embodiment, ink of four colors: cyan (C); magenta (M); yellow (Y); and black (B) is retained in the liquid container  14 . 
     The control device  22  collectively controls each of the components of the printing apparatus  10 . The transport mechanism  24  transports the medium  12  in the Y direction under control by the control device  22 . The liquid ejecting module  26  ejects ink supplied from the liquid container  14  onto the medium  12  under control by the control device  22 . The liquid ejecting module  26  of the first embodiment is a line head with a long dimension in the X direction that intersects with (typically orthogonal to) the Y direction. A desired image is formed on the surface of the medium  12  by the liquid ejecting module  26  ejecting ink onto the medium  12  in parallel with transport of the medium  12  by the transport mechanism  24 . Here, a direction which is perpendicular to the X-Y horizontal plane (the horizontal plane which is parallel to the surface of the medium  12 ) is represented below as the Z direction. The ejection direction of ink by the liquid ejecting module  26  is equivalent to the Z direction. 
       FIG. 2  is a planar diagram of an opposite surface of the liquid ejecting module  26  to the medium  12 . As exemplified in  FIG. 2 , the liquid ejecting module  26  includes a plurality of liquid ejecting units U which are arranged along the X direction.  FIG. 3  is an exploded perspective diagram of each liquid ejecting unit U. As exemplified in  FIGS. 2 and 3 , each of the plurality of liquid ejecting units U contains a plurality of (6) liquid ejecting heads  30  which are arranged along the X direction. A plurality of nozzles (ejection openings) N are formed on each liquid ejecting head  30 . As exemplified in  FIG. 3 , the six liquid ejecting heads  30  of the liquid ejecting module  26  are fixed to the surface of a fixing plate  32  with a flat plate form. Opening sections  322  which expose the nozzles N of each liquid ejecting head  30  are formed in the fixing plate  32 . Ink of four colors that is retained in the liquid container  14  is supplied in parallel to the plurality of liquid ejecting heads  30  of each liquid ejecting module  26  and ejected from the nozzles N of each liquid ejecting head  30 . 
       FIG. 4  is planar diagram focusing on an array of the plurality of nozzles N of the liquid ejecting head  30 . As exemplified in  FIG. 4 , the plurality of nozzles N of each liquid ejecting head  30  are classified into a first nozzle row N 1  and a second nozzle row N 2 . The first nozzle row N 1  and the second nozzle row N 2  respectively make up an aggregate of the plurality of nozzles N which are arranged along a W 1  direction (the first direction) within the X-Y horizontal plane. The total number of nozzles N making up the first nozzle row N 1  and the second nozzle row N 2  are equal. The W 1  direction is a direction which intersects with the X direction and the Y direction at a non-right-angle within the X-Y horizontal plane. In detail, the W 1  direction is inclined at an angle θ with respect to the Y direction. The angle θ is set to 30° to 60° inclusive (preferably, within the range of 30° to 40° inclusive, or 50° to 60° inclusive). As above, in the first embodiment, since the plurality of nozzles N are arranged in the W 1  direction which is inclined with respect to the Y direction along which the medium  12  is transported, in comparison to a configuration where the plurality of nozzles N are arranged along the X direction, it is possible to increase the practical dot density (resolution) of the medium  12  in the X direction. 
     The first nozzle row N 1  and the second nozzle row N 2  are arranged side by side with an interval from one another along a W 2  direction (the second direction) that intersects with (typically orthogonal to) the W 1  direction within the X-Y horizontal plane. As understood from  FIG. 4 , the first nozzle row N 1  and the second nozzle row N 2  of each liquid ejecting head  30  is arranged at an equal interval across each of the plurality of liquid ejecting heads  30 . When focusing on the first nozzle row N 1  and the second nozzle row N 2  which are adjacent to one another in the W 2  direction, the range in the X direction along which the plurality of nozzles N of the first nozzle row N 1  are distributed and the range in the X direction along which the plurality of nozzles N of the second nozzle row N 2  are distributed overlap one another. 
     Each nozzle N of the first nozzle row N 1  and each nozzle N of the second nozzle row N 2  have a common position in the X direction. That is, each nozzle N of the first nozzle row N 1  and each nozzle N of the second nozzle row N 2  are positioned on parallel straight lines in the Y direction. For example, a virtual line L links between the centers of one nozzle N which is positioned at an end section at the negative side in the W 1  direction out of the first nozzle row N 1  and one nozzle N which is positioned at an end section at the negative side in the W 1  direction out of the second nozzle row N 2  extends in a direction parallel to the Y direction and is inclined at the angle θ (30°≦θ≦60°) with respect to the W 1  direction. Accordingly, it is possible to cause ink which is ejected from the nozzles N of the first nozzle row N 1  and ink which is ejected from the nozzles N of the second nozzle row N 2  to overlap at the same position on the medium  12  which is transported in the Y direction. 
     In addition, the respective plurality of nozzles N of the first nozzle row N 1  and the second nozzle row N 2  are formed such that a pitch (a distance between the centers of each of the nozzles N which are adjacent to one another) PX of each nozzle N in the X direction and a pitch PY of each nozzle N in the Y direction have an integer ratio (for example, PX:PY=1:2). According to the configuration above, it is advantageous in that in a case where an image in which a plurality of pixels are arranged in a matrix form is printed on the medium  12 , a correspondence relationship between each pixel of the image which is specified by image data and each nozzle N of the liquid ejecting head  30  is simplified. 
     Each of the first nozzle row N 1  and the second nozzle row N 2  are utilized in ejection of ink of two different colors (four colors in total of the two colors of the first nozzle row N 1  and the second nozzle row N 2 ). In detail, as exemplified in  FIG. 4 , yellow (Y) ink is ejected from a prescribed number of nozzles N which are positioned at the negative side in the W 1  direction out of the first nozzle row N 1  of each liquid ejecting head  30  and cyan (C) ink is ejected from a prescribed number of nozzles N which are positioned at the positive side in the W 1  direction out of the first nozzle row N 1 . In addition, magenta (M) ink is ejected from a prescribed number of nozzles N which are positioned at the negative side in the W 1  direction out of the second nozzle row N 2  of each liquid ejecting head  30  and black (B) ink is ejected from a prescribed number of nozzles N which are positioned at the positive side in the W 1  direction out of the second nozzle row N 2 . In the configuration above, each of the nozzles N which correspond to the four different colors are arranged along the Y direction. Accordingly, it is possible to cause ink of the four colors to overlap at the same position on the medium  12  which is transported in the Y direction. 
       FIG. 5  is sectional diagram of one arbitrary liquid ejecting head  30  and is illustrated by the section of a line V-V in  FIG. 4  (section perpendicular to the W 1  direction). As exemplified in  FIG. 5 , the liquid ejecting head  30  has a structure (head chip) where a pressure chamber substrate  44 , a vibration plate  46 , a sealing body  52 , and a support body  54  are installed on an upper surface at the negative side in the Z direction on a flow path substrate  42 , and a nozzle plate  62  and a compliance section  64  are installed on an upper surface at the positive side in the Z direction on the flow path substrate  42 . Each of the components of the liquid ejecting head  30  is a member with a substantially flat plate shape with a long dimension in the W 1  direction in outline, and are fixed to one another utilizing, for example, an adhesive. 
     The plurality of nozzles N described above with reference to the  FIG. 4  are formed on the nozzle plate  62 . As understood from  FIG. 5 , a structure which corresponds to each nozzle N of the first nozzle row N 1  and a structure which corresponds to each nozzle N of the second nozzle row N 2  is formed in substantial line symmetry in each liquid ejecting head  30 , therefore the structure of the liquid ejecting head  30  will be described below focusing on the first nozzle row N 1  for convenience. 
     The flow path substrate  42  is a flat plate member which forms a flow path, and is formed by an opening section  422 , a supply flow path  424 , and a linking flow path  426 . The supply flow path  424  and the linking flow path  426  are formed in each nozzle N, and the opening section  422  links across the plurality of nozzles N which eject one color of ink. The pressure chamber substrate  44  is a flat plate member which is formed by a plurality of the opening sections  422  which correspond to different nozzles N. The flow path substrate  42  and the pressure chamber substrate  44  are formed, for example, from a silicon single crystal substrate. 
     The compliance section  64  of  FIG. 5  is a component for suppressing (absorbing) pressure variation within the flow path inside the liquid ejecting head  30 , and is configured to include, for example, a flexible member formed in a sheet form. In detail, the compliance section  64  is fixed on the surface of the flow path substrate  42  such that the opening section  422  of the flow path substrate  42  and each supply flow path  424  are blocked. 
     As exemplified in  FIG. 5 , the support body  54  is fixed to the surface at the negative side in the Z direction on the flow path substrate  42 . An accommodating section  542  and an introduction flow path  544  are formed in the support body  54 . The accommodating section  542  is a concave section (cavity) with an outer form which corresponds to the opening section  422  of the flow path substrate  42  in planar view (that is, viewed from the Z direction), and the introduction flow path  544  is a flow path which links to the accommodating section  542 . As understood from  FIG. 5 , the space, which links the opening section  422  of the flow path substrate  42  and the accommodating section  542  of the support body  54  with one another, functions as a liquid retaining chamber (reservoir) SR. The liquid retaining chamber SR is formed with each color of ink which is supplied from the liquid container  14  independent from one another, and retains ink which passes through the introduction flow path  544 . That is, the four liquid retaining chambers SR which correspond to different ink are formed inside one arbitrary liquid ejecting head  30 . The compliance section  64  in  FIG. 5  configures the bottom surface of the liquid retaining chamber SR and absorbs pressure variation in ink inside the liquid retaining chamber SR. 
     The pressure chamber substrate  44  is a flat plate member which is formed by the plurality of opening sections  442  which correspond to different nozzles N. The vibration plate  46  is installed on the surface on the opposite side to the flow path substrate  42  on the pressure chamber substrate  44 . The vibration plate  46  is a member with a flat plate form which is able to vibrate elastically. The vibration plate  46  is configured by, for example, a layer of an elastic film which is formed from an elastic material such as silicon oxide and an insulation film which is formed from an insulation material such as zirconium oxide. As understood from  FIG. 5 , the vibration plate  46  and the flow path substrate  42  are opposed so as to open a gap between one another at the inner side of each opening section  442  of the pressure chamber substrate  44 . The space which is interposed between the flow path substrate  42  and the vibration plate  46  at the inner side of each opening section  442  functions as a pressure chamber (cavity) SC in which pressure is imparted to ink. Each pressure chamber SC is linked to the nozzle N via each linking flow path  426  of the flow path substrate  42 . 
     A plurality of driving elements F which correspond to different nozzles N (pressure chambers SC) are formed on the surface which is opposite to the pressure chamber substrate  44  on the vibration plate  46 .  FIG. 6  is a sectional diagram (section perpendicular to the W 1  direction) which is enlarged in the vicinity of one arbitrary driving element F. As exemplified in  FIG. 6 , each of the plurality of driving elements F are piezoelectric elements containing a first driving electrode  72  which is formed on an upper surface of the vibration plate  46 , a piezoelectric body  74  which is formed on an upper surface on the first driving electrode  72 , and a second driving electrode  76  which is formed on an upper surface of the piezoelectric body  74 . An opposing region in which the first driving electrode  72  and the second driving electrode  76  interpose the piezoelectric body  74  functions as the driving element F. 
     The piezoelectric body  74  is formed, for example, in a process including heat treatment (firing). In detail, the piezoelectric body  74  is formed by a piezoelectric material which is coated on the surface of the vibration plate  46  on which a plurality of first driving electrodes  72  are formed being fired by means of heat treatment inside a firing furnace then molded (for example, milled utilizing plasma) in each driving element F. Each of the first driving electrodes  72  are individually formed in each driving element F and electrically insulated from one another, and each of the second driving electrodes  76  are individually formed in each driving element F and commonly connected to a wiring of a constant potential (for example, a reference potential such as a ground potential). Here, it is also possible to adopt a configuration in which the second driving electrode  76  is linked across the plurality of driving elements F. 
       FIG. 7  is a schematic diagram of each component viewed from the negative side (opposite side to the medium  12 ) of the liquid ejecting head  30  in the Z direction. As exemplified in  FIG. 7 , the plurality of driving elements F of the liquid ejecting head  30  are classified into a first element group G 1  and a second element group G 2 . The first element group G 1  is an aggregate of the plurality of driving elements F (first driving elements) which correspond to each nozzle N of the first nozzle row N 1  and the second element group G 2  is an aggregate of the plurality of driving elements F (second driving elements) which correspond to each nozzle N of the second nozzle row N 2 . The plurality of driving elements F of the first element group G 1  are arranged along the W 1  direction, and in the same manner the plurality of driving elements F of the second element group G 2  are also arranged along the W 1  direction. A prescribed number of the driving elements F which are positioned at the negative side in the W 1  direction within the first element group G 1  correspond to yellow (that is, yellow ink is ejected from the nozzles N by imparting pressure to the pressure chamber SC in which yellow ink is filled), and a prescribed number of the driving elements F which are positioned at the positive side in the W 1  direction within the first element group G 1  correspond to cyan. Meanwhile, a prescribed number of the driving elements F which are positioned at the negative side in the W 1  direction within the second element group G 2  correspond to magenta and a prescribed number of the driving elements F which are positioned at the positive side in the W 1  direction within the second element group G 2  correspond to black. 
     The first element group G 1  and the second element group G 2  are arranged side by side with an interval from one another along the W 2  direction. As exemplified in  FIG. 7 , a region in which mounting components are installed (hereinafter referred to as a “mounting region”) Q is secured between the first element group G 1  and the second element group G 2  on the surface of the vibration plate  46 . That is, the plurality of the driving elements F of the first element group G 1  and the plurality of the driving elements F of the second element group G 2  interpose the mounting region Q with a long dimension in the W 1  direction and are positioned at opposite sides to one another. In the first embodiment, as exemplified in  FIG. 5  and  FIG. 6 , a flexible wiring board  34  (COF: chip on film) for electrically connecting the liquid ejecting head  30  to an external apparatus (the control device  22  and a power supply circuit) is mounted in the mounting region Q as the mounting component. 
     The sealing body  52  in  FIG. 5  is a structure that protects each driving element F (for example, prevents adhesion of water or the like to the driving elements F) and reinforces the mechanical strength of the pressure chamber substrate  44  and the vibration plate  46 , and is fixed to the surface of the vibration plate  46  using, for example, an adhesive. Each driving element F is accommodated in a concave section which is formed on the surface at the vibration plate  46  side within the sealing body  52 . As exemplified in  FIG. 5 , the sealing body  52  of the first embodiment includes a first wall surface  521  which is positioned between the mounting region Q and the first element group G 1  in planar view and a second wall surface  522  which is positioned between the mounting region Q and the second element group G 2  in planar view. That is, the mounting region Q can be said to be a region which is interposed by the first wall surface  521  and the second wall surface  522  in planar view. 
     As exemplified in  FIG. 7 , a plurality of electrodes E are formed in the mounting region Q on the surface of the vibration plate  46 . Each electrode E is a conductive body which is formed (patterned) in a shape that extends in the W 2  direction in planar view, and is utilized electrically connected to each wiring on the wiring board  34  and each driving element F on the surface of the vibration plate  46 . The plurality of electrodes E within the mounting region Q includes the plurality of first electrodes E 1 , the plurality of second electrodes E 2 , and the plurality of third electrodes E 3 . Here, in a configuration in which the vibration plate  46  is removed in the mounting region Q, it is possible to form the plurality of electrodes E on the surface of the pressure chamber substrate  44 . 
     As exemplified in  FIG. 7 , the mounting region Q is classified into a first region A 1 , a second region A 2 , and a third region A 3 . The second region A 2  is positioned at the negative side in the W 1  direction viewed from the first region A 1  and the third region A 3  is positioned at the positive side in the W 1  direction viewed from the first region A 1 . That is, the first region A 1  is positioned between the second region A 2  and the third region A 3 . As understood from  FIG. 7 , the first region A 1  is equivalent to a region in which the first element group G 1  and the second element group G 2  (the first nozzle row N 1  and the second nozzle row N 2 ) overlap with one another along the W 1  direction. Meanwhile, the second region A 2  is equivalent to a region that the first element group G 1  does not overlap within the range in the W 1  direction in which the second element group G 2  is present, and the third region A 3  is equivalent to a region that the second element group G 2  does not overlap within the range in the W 1  direction in which the first element group G 1  is present. 
     The plurality of first electrodes E 1  are arranged at a prescribed pitch PW along the W 1  direction across the first region A 1  and the third region A 3  within the mounting region Q. Meanwhile, the plurality of second electrodes E 2  are arranged along the W 1  direction at the same pitch PW as each first electrode E 1  across the first region A 1  and the second region A 2  within the mounting region Q. Each of the plurality of first electrodes E 1  are electrically connected to each driving element F (the first driving elements) of the first element group G 1  extending to the positive side of the W 2  direction within the mounting region Q, and each of the plurality of second electrodes E 2  are electrically connected to each driving element F (the second driving elements) of the second element group G 2  extending to the negative side in the W 2  direction within the mounting region Q. In detail, as exemplified in  FIG. 6 , each first electrode E 1  and each second electrode E 2  is configured by layers of a connection wiring  82  and a connection terminal  84 . The connection wiring  82  is a conductive body (wiring) which is connected to the first driving element  72  of each driving element F. In the first embodiment, a configuration is exemplified in which the connection wiring  82  is linked to the same layer as the first driving electrode  72 , but it is possible to connect the connection wiring  82 , which is formed on a separate layer to the first driving electrode  72 , to the first electrode E 1 . Meanwhile, the connection terminal  84  is a conductive body (crimped terminal) which is formed on the surface of an end section at the opposite side to the driving elements F on the connection wiring  82 . 
     As exemplified in  FIG. 7 , the plurality of first electrodes E 1  and the plurality of second electrodes E 2  are alternately arranged along the W 1  direction at a half pitch P 0  of the pitch PW (P 0 =PW/2) within the first region A 1  in the mounting region Q. That is, the second electrode E 2  is positioned between two first electrodes E 1  which are adjacent to one another in the W 1  direction. The range in which the first electrodes E 1  are present along the W 2  direction and the range in which the second electrodes E 2  are present along the W 2  direction overlap with one another in the W 2  direction. That is, both the first electrodes E 1  and the second electrodes E 2  are present within a prescribed range α in the W 2  direction within the mounting region Q. 
     As exemplified in  FIG. 7 , the plurality of third electrodes E 3  are formed in each of the second region A 2  and the third region A 3 . Meanwhile, the third electrodes E 3  are not formed in the first region A 1 . In addition, the third electrodes E 3  of the first embodiment are not electrically connected to any of the driving elements F with respect to the first electrodes E 1  and the second electrodes E 2  which are electrically connected to each driving element F as above. That is, the third electrodes E 3  are dummy electrodes (ineffective wirings) that do not actually contribute to operation (ink ejection) of the driving elements F. 
     Each of the plurality of third electrodes E 3  is formed on the same layer as the first electrodes E 1  and the second electrodes E 2  (the layer of the connection wiring  82  and the connection terminal  84 ). Each third electrode E 3  which is formed within the second region A 2  in the mounting region Q is positioned between two second electrodes E 2  which are adjacent to one another at the pitch PW along the W 1  direction within the second region A 2 . In detail, as exemplified in  FIG. 7 , the second electrodes E 2  and the third electrodes E 3  are alternately arranged along the W 1  direction within the second region A 2  at a pitch P 0  which is the same as the pitch P 0  at which the first electrodes E 1  and the second electrodes E 2  are arranged within the first region A 1  of the mounting region Q. Meanwhile, each third electrode E 3  which is formed within the third region A 3  in the mounting region Q is positioned between two first electrodes E 1  which are adjacent to one another at the pitch PW along the W 1  direction within the third region A 3 . In detail, as exemplified in  FIG. 7 , the first electrodes E 1  and the third electrodes E 3  are alternately arranged along the W 1  direction within the third region A 3  at the same pitch P 0  at which the first electrodes E 1  and the second electrodes E 2  are arranged within the first region A 1 . As understood from the above explanation, in the first embodiment, the plurality of electrodes E, across the entire mounting region Q which includes the second region A 2  and the third region A 3  in addition to the first region A 1 , are arranged at the equal pitch P 0  along the W 1  direction. 
     The range in which the third electrodes E 3  are present along the W 2  direction within the mounting region Q overlaps with the range of the first electrodes E 1  and the second electrodes E 2  in the W 2  direction. That is, each third electrode E 3  is present in the second region A 2  and the third region A 3  within the range α in which the first electrodes E 1  and the second electrodes E 2  overlap and are present within the mounting region Q. 
     As above, the flexible wiring board  34  is mounted in the mounting region Q. As exemplified in  FIG. 6 , the wiring board  34  is fixed to the surface of the vibration plate  46  using adhesive  36  in a state where the connection terminal  342  (wiring) which is formed on the surface of the wiring board  34  is in contact with each electrode E (connection terminal  84 ) on the surface of the vibration plate  46 . In detail, the adhesive  36  with a liquid form is coated within the mounting region Q (range α), and the wiring board  34  is mounted on the liquid ejecting head  30  by curing the adhesive  36  in a state where an end section of the wiring board  34  is pressed on the surface of the vibration plate  46 . Driving signals for controlling each of the driving elements F are supplied from each of the connection terminals  342  of the wiring board  34  to each of the driving elements F of the first element group G 1  via the first electrodes E 1  and supplied to each of the driving elements F of the second element group G 2  via the second electrodes E 2 . 
     A configuration in which the third electrodes E 3  are not formed in the second region A 2  or the third region A 3  is assumed as a comparative example of the first embodiment. In the comparative example, the first electrodes E 1  and the second electrodes E 2  are alternatively arranged within the first region A 1  at the pitch P 0  along the W 1  direction, but only the second electrodes E 2  are arranged within the second region A 2  at the pitch PW and only the first electrodes E 1  are arranged within the third region A 3  at the pitch PW. That is, the densities of the electrodes E in the second region A 2  and the third region A 3  are different from the first region A 1 . In detail, the densities of each of the electrodes E of the second electrodes E 2  and the third electrodes E 3  are lower than the densities in the first region A 1 . In the comparative example above, it is possible to distribute the adhesive  36  which is coated on the surface of the vibration plate  46  for mounting on the wiring board  34  in a narrow space between the first electrodes E 1  and the second electrodes E 2  which are adjacent to one another at the pitch P 0  in the first region A 1  and in a wide space between each of the second electrodes E 2  which are adjacent to one another at the pitch PW (PW=P 0 ×2) in the second region A 2 . Accordingly, in a case where the coating amount of the adhesive  36  is selected so as to optimally distribute the adhesive  36  within the first region A 1 , the adhesive  36  is insufficient within the second region A 2  and as a result it becomes difficult to sufficiently secure the adhesive strength of the wiring board  34 . Meanwhile, excess of the adhesive  36  within the first region A 1  becomes a problem in a case where the coating amount of the adhesive  36  is selected so as to optimally distribute the adhesive  36  within the second region A 2 . For example, in a case in which there is an excess of the adhesive  36  within the first region A 1 , the adhesive  36  in the first region A 1  flows within a wide range and reaches the sealing body  52  in a process in which the wiring board  34  is pressed with respect to the vibration plate  46 , and there is a problem of positional deviation of the wiring board  34  due to stress from the adhesive  36  which is blocked by the first wall surface  521  and the second wall surface  522 . Here, the first region A 1  and the second region A 2  are focused on for convenience in the explanation above, but it is possible for the problem to occur in the same manner in the third region A 3 . 
     In contrast to the comparative example exemplified above, in the first embodiment, while the first electrodes E 1  and the second electrodes E 2  are arranged alternatively at the pitch P 0  within the first region A 1 , the third electrodes E 3  are formed between the two second electrodes E 2  adjacent to one another within the second region A 2 , and the third electrodes E 3  are formed between the two first electrodes E 1  adjacent to one another within the third region A 3 . That is, in the first embodiment, a difference (a difference between the first region A 1  and the second region A 2  or the third region A 3 ) in densities of the electrodes E within the mounting region Q are suppressed in comparison to the comparative example, Accordingly, according to the first embodiment, it is advantageous in that it is possible to eliminate the problem above (insufficient adhesive strength or positional error of the wiring board  34 ) in the comparative example caused by a difference in densities of the electrodes E within the mounting region Q. In the first embodiment, in particular, since the second electrodes E 2  and the third electrodes E 3  are arranged within the second region A 2  at the same pitch P 0  as an array of the first electrodes E 1  and the second electrodes E 2  within the first region A 1 , the result described above where the difference in densities of the electrodes E between the first region A 1  and the second region A 2  is suppressed is particularly remarkable. Here, the problem described above where a positional error occurs due to the excess adhesive  36  being pressed on the wiring board  34  occurs as a result of the excess portion of the adhesive  36  reaching the sealing body  52  and blocking the wiring board  34  using the first wall surface  521  and the second wall surface  522 . When considering the above circumstances, in the first embodiment, a configuration is particularly preferable in which the sealing body  52  is installed with a shape where the first wall surface  521  is positioned between the mounting region Q and the first element group G 1  and the second wall surface  522  is positioned between the mounting region Q and the second element group G 2 . 
     Here, in the explanation above, the problem which is related to adhesion of the wiring board  34  is exemplified, but the problem which is caused by the densities of the electrodes E within the mounting region Q is not limited to the exemplification above. For example, in the comparative example in which the third electrodes E 3  are not formed, since the degree of heat conduction is different between the first region A 1  in which the density (pitch P 0 ) of the plurality of electrodes E is high and the second region A 2  in which the density (pitch PW) of the plurality of electrodes E is low, for example, in a process in which the piezoelectric body  74  is fired using heat treatment, it is possible for a difference in temperature (heat distribution bias) between the first region A 1  and the second region A 2  or the third region A 3  to be generated. In a state in which heat distribution is biased as above, it is possible for the problem such as film formation failure to occur in a component which is formed in each of the following processes. Meanwhile, in the first embodiment in which the third electrodes E 3  are formed in the second region A 2  and the third region A 3 , heat distribution within the mounting region Q is uniformized since the densities of the electrodes E within the mounting region Q are suppressed. Accordingly, it is advantageous in that it is possible to prevent the problem such as film formation failure which is caused by heat distribution bias. As understood from the above explanation, the result of the first embodiment described above in which the densities of the plurality of electrodes E within the mounting region Q are uniformized by forming the third electrodes E 3  is able to be sufficiently exhibited even in a configuration in which adhesion of the wiring board  34  is not assumed. That is, a configuration in which the wiring board  34  is adhered utilizing the adhesive  36  is not essential in the invention. 
     Second Embodiment 
     The second embodiment of the invention will be described below. Here, in each of the aspects exemplified below, concerning components which have the same actions and functions as the first embodiment, detailed explanation will be omitted as appropriate by using the same reference numerals which are explained in the first embodiment. 
       FIG. 8  is a schematic diagram of each component viewed from the negative side in the Z direction of the liquid ejecting head  30  according to a second embodiment. As exemplified in  FIG. 8 , the liquid ejecting head  30  of the second embodiment includes a plurality of dummy elements FD which are not actually utilized in ejection of ink. In detail, as exemplified in  FIG. 8 , the plurality of dummy elements FD are formed between the plurality of driving elements F which correspond to yellow and the plurality of driving elements F which correspond to cyan out of the first nozzle row G 1  (that is, between colors of the first nozzle row N 1 ) and the plurality of dummy elements FD are formed between the plurality of driving elements F which correspond to magenta and the plurality of driving elements F which correspond to black out of the second nozzle row G 2 . Each dummy element FD is configured by layers of the first driving electrode  72 , the piezoelectric body  74 , and the second driving electrode  76  in the same manner as the driving elements F which are actually utilized in ejection of ink. 
     A pressure chamber SD which corresponds to each dummy element FD is formed on the pressure chamber substrate  44  of the second embodiment. The pressure chamber SD is formed with a structure in the same manner (common or similar) as the pressure chamber SC which corresponds to the driving elements F and is a pseudo-space which is not actually utilized in ejection of ink. In detail, ink is supplied from the liquid retaining chamber SR to each pressure chamber SD, but the linking flow path  426  and the nozzles N are not formed on the downstream side of the pressure chamber SD. Accordingly, ink is not ejected even if pressure inside the pressure chamber SD varies. As understood from the above explanation, even though each dummy element FD is formed with the structure in the same manner (common or similar) as the driving elements F which are actually utilized in ejection of ink, but is actually a pseudo-element that does not contribute to ejection of ink. 
     In the second embodiment, the first region A 1  of the mounting region Q is classified into a region RA and a region RB. The region RA is positioned at the positive side in the W 1  direction viewed from the region RB. The region RA includes a region RA 1  at the third region A 3  side and a region RA 2  which is positioned at the negative side in the W 1  direction viewed from the region RA 1 , and the region RB includes a region RB 1  at the second region A 2  side and a region RB 2  which is positioned at the positive side in the W 1  direction viewed from the region RB 1 . The region RA 2  is positioned between the plurality of dummy elements FD of the first element group G 1  and the black driving elements F of the second element group G 2 , and the region RB 2  is positioned between the plurality of dummy elements FD of the second element group G 2  and the yellow driving elements F of the first element group G 1 . 
     In the region RA 1  of the mounting region Q, the plurality of first electrodes E 1  which are connected to each driving element F of the first element group G 1  are arranged at the pitch PW along the W 1  direction. In addition, the plurality of second electrodes E 2  which are connected to each driving element F of the second element group G 2  are arranged at the pitch PW along the W 1  direction across the region RA 1  and the region RA 2 . Accordingly, in the region RA 1 , the plurality of first electrodes E 1  and the plurality of second electrodes E 2  are arranged alternatively at the pitch P 0  along the W 1  direction in the same manner as the first region A 1  of the first embodiment. Meanwhile, since each dummy element FD is not actually utilized in ejection of ink, the electrodes E which correspond to each dummy element FD are inherently unnecessary. However, in the second embodiment, as exemplified in  FIG. 8 , the plurality of third electrodes E 3  which are electrically connected to each dummy element FD are formed in the region RA 2 . In the region RA 2 , in the same manner as within the second region A 2 , the plurality of second electrodes E 2  and the plurality of third electrodes E 3  are alternatively arranged at the pitch P 0  along the W 1  direction such that the third electrodes E 3  are positioned between each second electrode E 2  which are adjacent to one another. 
     The plurality of electrodes E are arranged in the same manner within the region RB. That is, the first electrodes E 1  and the second electrodes E 2  are arranged alternatively at the pitch P 0  along the W 1  direction within the region RB 1 , and the first electrodes E 1  which are connected to each driving element F of the first element group G 1  and the third electrodes E 3  which are connected to each dummy element FD are arranged alternatively at the pitch P 0  along the W 1  direction in the region RB 2 . 
     The array of each electrode E in the second region A 2  and the third region A 3  is the same as the first embodiment. Accordingly, similar effects to those in the first embodiment are also realized in the second embodiment. In addition, in the second embodiment, since the third electrodes E 3  are formed in the region RA 2  and the region RB 2  in the same manner as the second region A 2  and the third region A 3 , for example, in comparison to a configuration in which the third electrodes E 3  are not formed in the region RA 2  and the region RB 2 , a difference in densities of the electrodes E between the region RA 1  and the region RA 2  or between the region RB 1  and the region RB 2  is reduced. Accordingly, in the same manner as the first embodiment, it is advantageous in that it is possible to eliminate the problem described above (insufficient adhesive strength or positional error of the wiring board  34 ) caused by a difference in densities of the electrodes E within the mounting region Q. As understood from the above explanation, the “third electrodes” in the invention also include the third electrodes E 3  which are formed in the region RA 2  and the region RB 2  which correspond to the dummy elements FD in addition to the third electrodes E 3  which are formed in the second region A 2  and the third region A 3 . 
     Here, in the second embodiment, a configuration is exemplified in which the third electrodes E 3  which are formed in the region RA 2  and the region RB 2  are connected to the dummy elements FD. That is, the electrical configuration to the wiring board  34  is common between the driving elements F and the dummy elements FD. In  FIG. 8 , a configuration (hereinafter referred to as “configuration  1 ”), in which an ink flow path which corresponds to each dummy element FD is blocked, is exemplified, but as long as the ink flow path which corresponds to each dummy element FD is linked from the liquid retaining chamber SR to the nozzles N, a configuration (hereinafter referred to as “configuration  2 ”) in which ink is ejected utilizing each dummy element FD as a normal driving element F is realized. Configuration  1  is preferable in a case where ink of a plurality of colors is ejected by the respective first element group G 1  and the second element group G 2 , and configuration  2  is preferable in a case, for example, where ink of one color (for example, black) is ejected from all of the nozzles N. As understood from the above explanation, in the second embodiment, it is advantageous in that it is possible to commonly use an electrical structure from each of the driving elements F to the wiring board  34  in configuration  1  and configuration  2  (thus structural costs are reduced). However, it is also possible to adopt a configuration in which the third electrodes E 3  within the region RA 2  and the region RB 2  which are not electrically connected to each dummy element FD (for example, a configuration in which the third electrodes E 3  are formed so as to be included in the range α within the region RA 2  or within the region RB 2 ). 
     Third Embodiment 
       FIG. 9  is a schematic diagram of each component viewed from the negative side in the Z direction of the liquid ejecting head  30  according to a third embodiment. As exemplified in  FIG. 9 , in the third embodiment, a plurality of pressure chambers SD are formed at the positive side and the negative side in the W 1  direction viewed from the pressure chambers SC which correspond to each of the driving elements F of the first element group G 1 . In the same manner, a plurality of the pressure chambers SD are formed at the positive side and the negative side in the W 1  direction viewed from the pressure chambers SC which correspond to each of the driving elements F of the second element group G 2 . In the same manner to the second embodiment, each pressure chamber SD is formed with a structure in the same manner as the pressure chamber SC and is a pseudo-space which is not actually utilized in ejection of ink. 
     In the configuration where the pressure chambers SD are not formed at both sides of the array of the plurality of pressure chambers SC (for example, the first embodiment), it is possible that pressure variation conditions in the pressure chambers SC which are positioned at both end sections of the array and the pressure chambers SC which are positioned near the center of the array out of the plurality of pressure chambers SC (whether other pressure chambers SC are present only at one side in the W 1  direction, or whether other pressure chambers SC are present at both sides in the W 1  direction) are different. Accordingly, it is possible that ejection characteristics (the amount of ejection or the speed of ejection) of ink from each nozzle N in each of the first nozzle row N 1  and the second nozzle row N 2  are different according to the position of the nozzle N. In the third embodiment, since a dummy pressure chamber SD is formed in the configuration in the same manner as each pressure chamber SC on both sides of the array of the plurality of pressure chambers SC, it is possible for pressure variation conditions to be close between the pressure chambers SC which are positioned at both end sections of the array and the pressure chambers SC which are positioned near the center of the array out of the plurality of pressure chambers SC. Accordingly, it is advantageous in that the ejection characteristics of ink from each of the nozzles N is uniformized at both end sides and near to the center in each of the first nozzle row N 1  and the second nozzle row N 2 . 
     In the third embodiment, the second region A 2  of the mounting region Q is classified into a region A 21  and a region A 22 . The region A 21  is a region at the first region A 1  side within the second region A 2  and the region A 22  is a region at the opposite side to the first region A 1  within the second region A 2 . Each driving element F of the second element group G 2  is present at the negative side in the W 2  direction viewed from the region A 21 . In the same manner as the second region A 2  of the first embodiment, the second electrodes E 2  which are connected to the driving elements F are formed in the region A 21 , and the second electrodes E 2  and the third electrodes E 3  are arranged in the W 1  direction at the pitch P 0  such that the third electrodes E 3  are positioned between each of the second electrodes E 2  which are adjacent to one another. Accordingly, similar effects to those in the first embodiment are also realized in the third embodiment. 
     Meanwhile, since the driving elements F are not present at either of the positive side or the negative side in the W 2  direction of the region A 22  within the second region A 2 , neither the first electrodes E 1  nor the second electrodes E 2  are formed in the region A 22 . As exemplified in  FIG. 9 , in the third embodiment, the plurality of third electrodes E 3  are formed in the region A 22 . The plurality of third electrodes E 3  are arranged in the region A 22  along the W 1  direction at the same pitch P 0  as the array of the first electrodes E 1  and the second electrodes E 2  in the first region A 1  and the array of the second electrodes E 2  and the third electrodes E 3  in the region A 21  of the second region A 2 . 
     The second region A 2  is focused on in the explanation above, but a configuration is also adopted in the same manner in the third region A 3 . That is, the plurality of first electrodes E 1  and the plurality of third electrodes E 3  are arranged at the pitch P 0  along the W 1  direction in a region A 31  at the first region A 1  side within the third region A 3  and the plurality of third electrodes E 3  are arranged at the pitch P 0  along the W 1  direction in a region A 32  at the opposite side to the first region A 1  within the third region A 3 . 
     As explained above, in the third embodiment, the plurality of third electrodes E 3  are arranged along the W 1  direction at the pitch P 0  in the region A 22  at the opposite side to the first region A 1  within the second region A 2 . Accordingly, it is advantageous in that the densities of the electrodes E across a wide range including the region A 22  in which the second electrodes E 2  are not present in addition to the region A 21  in which the second electrodes E 2  are present in the second region A 2  are uniformized. In the same manner, concerning the third region A 3 , it is advantageous in that the densities of the electrodes E across a wide range including the region A 32  in which the first electrodes E 1  are not present in addition to the region A 31  in which the first electrodes E 1  are present are uniformized. Here, it is also possible to apply the configuration of the second embodiment to the third embodiment. 
     Fourth Embodiment 
       FIG. 10  is a schematic diagram of each component viewed from the negative side in the Z direction of the liquid ejecting head  30  according to a fourth embodiment. In the third embodiment, the dummy pressure chambers SD are formed on both sides of the array of the plurality of pressure chambers SC. In the fourth embodiment, in addition to the configuration of the third embodiment, dummy elements FD are formed which correspond to each of the pressure chambers SD. Each dummy element FD is formed in a structure in the same manner as the driving elements F, but is a pseudo-element that is not actually utilized in ejection of ink, as described above in the second embodiment, the first driving electrode  72 , the piezoelectric body  74 , and the second driving electrode  76  configure a layer in the same manner as each of the driving elements F. As understood from the above explanation, in the fourth embodiment, the dummy elements FD which include the first driving electrode  72  (fourth electrode), the piezoelectric body  74 , and the second driving electrode  76  are formed at both sides in the W 1  in each of the first element group G 1  and the second element group G 2  (the opposite side to the other end section which interposes one end section in an array of the plurality of driving elements F). 
     As understood from  FIG. 10 , an interval d 1  between the first driving electrode  72  of each of the driving elements F of the first element group G 1  and the first driving electrode  72  of each of the driving elements F of the second element group G 2  is wide in comparison to a range d 2  in which the first driving electrode  72  of the plurality of dummy elements FD is distributed at the positive side in the W 1  direction in the first element group G 1  or at the negative side in the W 1  direction in the second element group G 2  (d 1 &gt;d 2 ). 
     Similar effects to those in the third embodiment are also realized in the fourth embodiment. Here, as described above, the piezoelectric body  74  of each driving element F is formed by a piezoelectric material which is coated on the surface of the vibration plate  46  being fired by means of heat treatment inside a firing furnace then separated into each driving element F. Since the degree of heat conduction is different in a region in which the first driving electrode  72  is formed on the surface of the vibration plate  46  and a region in which the first driving electrode  72  is not formed, it is possible for a difference in temperature (bias of distribution on the X-Y horizontal plane) to occur according to presence or absence of the first driving electrode  72  in a heat treatment stage in a process in which the piezoelectric body  74  is formed. In the third embodiment, since the first driving electrode  72  of the dummy elements FD is formed in a region which corresponds to each pressure chamber SD in addition to the first driving electrode  72  of the driving elements F being formed in a region which corresponds to each pressure chamber SC, heat distribution is uniformized at the region of each pressure chamber SC and the region of each pressure chamber SD. Accordingly, it is advantageous in that it is possible to prevent the problem such as film formation failure of the piezoelectric material which is caused by heat distribution bias. Here, it is also possible to apply the configuration of the second embodiment to the fourth embodiment. 
     Modification Example 
     It is possible for the aspects which are exemplified above to be variously modified. Modified aspects will be exemplified in detail below. It is possible to appropriately combine two or more aspects which are arbitrarily selected from the above exemplifications within a range which is not mutually inconsistent. 
     (1) In each aspect described above, a configuration is exemplified in which a driving signal is supplied to the first driving electrode  72  which is positioned at the vibration plate  46  side out of the driving elements F (the dummy elements FD) and the second driving electrode  76  at the opposite side to the vibration plate  46  is set to a common constant potential, but it is also possible to adopt a configuration in which each first driving electrode  72  is set with a common constant potential and the driving signal of each driving element F is supplied to each second driving electrode  76 . In addition, in the aspect described above, the structure of the dummy elements FD are exemplified in the same manner as the driving elements F, but the structure of the dummy elements FD is not limited to the exemplification above. For example, it is possible to form the structure of the dummy elements FD in which a portion of the first driving element  72 , the piezoelectric body  74 , and the second driving electrode  76  is omitted. 
     (2) In each aspect described above, a configuration is exemplified in which the first nozzle row N 1  and the second nozzle row N 2  are formed on one liquid ejecting head  30 , but the number of the nozzle row on which one liquid ejecting head  30  is formed is appropriately modified. For example, it is also possible to adopt a configuration in which the plurality of nozzles N of one liquid ejecting head  30  are arranged on a third row or above. 
     (3) In each aspect described above, a configuration is exemplified in which each nozzle N of the first nozzle row N 1  and each nozzle N of the second nozzle row N 2  have a common position in the X direction, but the position of each nozzle N is not limited to the above exemplification. For example, as exemplified in  FIG. 11 , it is also possible to make the positions of each nozzle N of the first nozzle row N 1  and each nozzle N of the second nozzle row N 2  different in the X direction. In  FIG. 11 , a configuration is exemplified in which the position of each nozzle N of the first nozzle row N 1  and each nozzle N of the second nozzle row N 2  are made different in the X direction by half of the pitch PX (PX/2) of each nozzle N in the X direction of the first nozzle row N 1  (or the second nozzle row N 2 ). 
     According to the configuration of  FIG. 11 , in comparison to the configuration in which the plurality of nozzles N are arranged as exemplified in  FIG. 4 , it is possible to increase (double) the practical dot density in the X direction of the medium  12 . 
     (4) A pitch P of the array of the plurality of electrodes E is defined as the distance between the centers of each of the electrodes E which are adjacent to one another. For example, as exemplified in  FIG. 12 , when focusing on an electrode EA and an electrode EB which are adjacent to one another, the distance between a center (center of gravity) eA of the electrode EA and a center eB of the electrode EB is equivalent to the pitch P. The centers e (eA and eB) of each electrode E, for example, are defined as intersection points between a center line along a direction (longitudinal direction) in which the electrodes E extend and a center line in the width direction of the electrodes E, and the form and the direction of each of the electrodes E is not relevant. 
     (5) The components which vary the pressure inside the pressure chamber SC (the driving elements F) are not limited to the piezoelectric elements exemplified in each aspect described above. For example, it is also possible to utilize an oscillator such as an electrostatic actuator as the driving elements F. In addition, the driving elements F are not limited to components which impart mechanic vibration to the pressure chambers SC. For example, it is also possible to utilize a heat generating element (heater) which, varies the pressure by generating bubbles inside the pressure chambers SC by heating, as the driving element F. As understood from the exemplification above, the driving elements F are included as components (pressure generating elements) which impart pressure inside the pressure chambers SC, and neither the method by which pressure is imparted (piezo system/thermal system) nor the detailed configuration are relevant. 
     (6) It is possible to adopt the printing apparatus  10  which is exemplified in each of the aspects above in various devices other than a device which is specialized for printing such as a facsimile apparatus or a copy machine. However, the applications of the liquid ejecting apparatus of the invention are not limited to printing. For example, a liquid ejecting apparatus which ejects color liquid is utilized as a manufacturing apparatus which forms a color filter of a liquid crystal display apparatus. In addition, a liquid ejecting apparatus which ejects a conductive material solution is utilized as a manufacturing apparatus which forms an electrode and a wiring of a wiring substrate.