Patent Publication Number: US-11396180-B2

Title: Inkjet head manufacturing method, inkjet recording device manufacturing method, inkjet head, and inkjet recording device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is the U.S. national stage of application No. PCT/JP2017/046532, filed on Dec. 26, 2017. Priority under 35 U.S.C. § 119(a) and 35 U.S.C. § 365(b) is claimed, the disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to an inkjet head manufacturing method, an inkjet recording device manufacturing method, an inkjet head, and an inkjet recording device. 
     BACKGROUND ART 
     There has been conventionally an inkjet recording device which causes nozzles provided in inkjet heads to eject ink to form images or the like. As the inkjet head in the inkjet recording device, a head chip having nozzles and a flow path substrate provided with ink flow paths communicating with the nozzles is known. 
     As the flow path substrate used in the head chip, silicon and stainless steel are often used from the viewpoint of easiness of process. However, the substrate made of these materials have a problem that the substrate can be corroded by ink at the parts contacting the ink. When the ink flow path is corroded by ink or the surface of the flow path substrate is corroded by ink to allow the ink enter the flow path substrate, a desired amount of ink cannot be supplied to the nozzles, or ink leakage via unintended paths occur. 
     With respect to this, there has been conventionally a technique which suppresses the corrosion by ink by forming a protective film on the surface of flow path substrate and the inner wall surfaces of ink flow paths (for example, Patent Document 1). When a plurality of flow path substrates on which this protective film is formed is manufactured, there can be used a method of manufacturing a composite substrate having a plurality of regions which forms flow path substrates by being split, forming the protective film on the surface of the composite substrate and the inner wall surfaces of the ink flow paths, and thereafter splitting the composite substrate into each flow path substrate. 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         Patent Document 1: Japanese Patent Application Laid Open Publication No. 2014-198460 
       
    
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     However, in the flow path substrate manufactured by the above method, the protective film is not provided on the split face generated by the splitting of the composite substrate. Thus, there is a problem that the flow path substrate can be corroded by ink adhering to the split face when the split face is exposed in the surface of the head chip. 
     An object of this invention is to provide an inkjet head manufacturing method, an inkjet recording device manufacturing method, an inkjet head, and an inkjet recording device that can more surely suppress the corrosion of flow path substrate caused by ink. 
     Means for Solving the Problem 
     In order to achieve the above object, the invention of an inkjet head manufacturing method according to claim  1  is an inkjet head manufacturing method for an inkjet head that includes a head chip including: a nozzle that ejects ink; and a flow path substrate including an ink flow path which communicates with the nozzle and through which the ink flows, the method including: composite substrate manufacturing that is manufacturing a composite substrate including a plurality of regions which forms flow path substrates by being split, each of the flow path substrates being the flow path substrate; first protective film forming that is forming a first protective film on a surface of the composite substrate and an inner wall surface of the ink flow path; splitting that is splitting the composite substrate into the flow path substrates; and second protective film forming that is forming a second protective film on at least an exposed face in a split face of the flow path substrate generated in the splitting, the exposed face being exposed in a surface of the head chip. 
     The invention according to claim  2  is the inkjet head manufacturing method according to claim  1 , further including nozzle substrate fixing that is directly or indirectly fixing a nozzle substrate, in which an opening of the nozzle is provided, to the flow path substrate after the second protective film forming. 
     The invention according to claim  3  is the inkjet head manufacturing method according to claim  1 , further including nozzle substrate fixing that is directly or indirectly fixing a nozzle substrate, in which an opening of the nozzle is provided, to the flow path substrate before the second protective film forming, wherein the second protective film is formed on a surface of a layered substrate including the flow path substrate and the nozzle substrate in the second protective film forming. 
     The invention according to claim  4  is the inkjet head manufacturing method according to claim  2  or  3 , further including exterior member bonding that is bonding an exterior member to the head chip including the nozzle substrate and the flow path substrate with an adhesive after the second protective film forming, the exterior member covering a part of the head chip while exposing a nozzle opening surface of the nozzle substrate in which the opening of the nozzle is provided, wherein a predetermined region excluding at least a part or whole of the exposed face of the flow path substrate in the surface of the head chip is bonded to the exterior member with the adhesive in the exterior member bonding. 
     The invention according to claim  5  is the inkjet head manufacturing method according to claim  4 , in which the exterior member includes a recess, a through hole is provided in the exterior member, the through hole including an opening in an inner wall surface of the recess, and in the exterior member bonding, the exterior member is bonded to the head chip such that a portion including the nozzle opening surface and at least a part of the exposed face in the head chip protrudes outside the exterior member from the opening of the through hole. 
     The invention according to claim  6  is the inkjet head manufacturing method according to any one of claims  1  to  5 , in which the first protective film is an inorganic oxide or an inorganic nitride that includes at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta and Si, or polyparaxylylene. 
     The invention according to claim  7  is the inkjet head manufacturing method according to any one of claims  1  to  6 , in which the second protective film is an inorganic oxide or an inorganic nitride that includes at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta and Si, or polyparaxylylene. 
     The invention according to claim  8  is the inkjet head manufacturing method according to any one of claims  1  to  7 , in which the flow path substrate is made of Si, metal or glass. 
     In order to achieve the above object, the invention of an inkjet recording device manufacturing method according to claim  9  is an inkjet recording device manufacturing method including the inkjet head manufacturing method according to any one of claims  1  to  8 . 
     In order to achieve the above object, the invention of an inkjet head according to claim  10  is an inkjet head including a head chip including: a nozzle that ejects ink; and a flow path substrate including an ink flow path which communicates with the nozzle and through which the ink flows, in which the flow path substrate includes a lateral surface in which an opening of the ink flow path is not provided, a first protective film is provided on a surface of the flow path substrate excluding at least a part of the lateral surface and on an inner wall surface of the ink flow path, at least a part of a portion where the first protective film is not provided in the lateral surface is an exposed face that is exposed in a surface of the head chip, and a second protective film that is not integrally formed with the first protective film is provided on the exposed face. 
     The invention according to claim  11  is the inkjet head according to claim  10 , in which the portion where the first protective film is not provided in the lateral surface is a split face that is generated in splitting a composite substrate into flow path substrates each of which is the flow path substrate, the composite substrate including a plurality of regions which forms the flow path substrates by being split. 
     The invention according to claim  12  is the inkjet head according to claim  10  or  11 , in which the head chip includes a nozzle substrate in which an opening of the nozzle is provided, and the second protective film is provided on a surface of a layered substrate including the flow path substrate and the nozzle substrate. 
     The invention according to claim  13  is the inkjet head according to any one of claims  10  to  12 , further including an exterior member that covers a part of the head chip while exposing a nozzle opening surface of a nozzle substrate in which an opening of the nozzle is provided, in which the head chip includes the nozzle substrate in which the opening of the nozzle is provided, and a predetermined region excluding at least a part or whole of the exposed face of the flow path substrate in the surface of the head chip is bonded to the exterior member with an adhesive. 
     The invention according to claim  14  is the inkjet head according to claim  13 , in which the exterior member includes a recess, a through hole is provided in the exterior member, the through hole including an opening in an inner wall surface of the recess, and a portion including the nozzle opening surface and at least a part of the exposed face in the head chip protrudes outside the exterior member from the opening of the through hole. 
     The invention according to claim  15  is the inkjet head according to any one of claims  10  to  14 , in which the first protective film is an inorganic oxide or an inorganic nitride that includes at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta and Si, or polyparaxylylene. 
     The invention according to claim  16  is the inkjet head according to any one of claims  10  to  15 , in which the second protective film is an inorganic oxide or an inorganic nitride that includes at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta and Si, or polyparaxylylene. 
     The invention according to claim  17  is the inkjet head according to any one of claims  10  to  16 , in which the flow path substrate is made of Si, metal or glass. 
     In order to achieve the above object, the invention of an inkjet recording device according to claim  18  is an inkjet recording device including the inkjet head according to any one of claims  10  to  17 . 
     Effects of the Invention 
     According to the present invention, there is an effect that it is possible to more surely suppress the corrosion of flow path substrate caused by ink. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view showing an outline configuration of an inkjet recording device. 
         FIG. 2  is a schematic view showing the configuration of a head unit. 
         FIG. 3  is a perspective view of an inkjet head. 
         FIG. 4  is an exploded perspective view of main parts of the inkjet head. 
         FIG. 5  is an enlarged plan view of a pressure chamber substrate. 
         FIG. 6  is a schematic sectional view of a portion including a head chip in the inkjet head. 
         FIG. 7  is a schematic sectional view showing a part of  FIG. 6  by enlarging the part. 
         FIG. 8  is a schematic sectional view of a portion including a head chip in an inkjet head. 
         FIG. 9  is a flowchart explaining an inkjet head manufacturing process. 
         FIG. 10A  is a sectional view explaining a nozzle substrate manufacturing method. 
         FIG. 10B  is a sectional view explaining the nozzle substrate manufacturing method. 
         FIG. 10C  is a sectional view explaining the nozzle substrate manufacturing method. 
         FIG. 11A  is a sectional view explaining a flow path spacer substrate manufacturing method. 
         FIG. 11B  is a sectional view explaining the flow path spacer substrate manufacturing method. 
         FIG. 11C  is a sectional view explaining the flow path spacer substrate manufacturing method. 
         FIG. 12A  is a sectional view explaining an inkjet head manufacturing method. 
         FIG. 12B  is a sectional view explaining the inkjet head manufacturing method. 
         FIG. 12C  is a sectional view explaining the inkjet head manufacturing method. 
         FIG. 13  is an enlarged schematic sectional view of an inkjet head according to a modification example of a first embodiment. 
         FIG. 14  is a flowchart explaining an inkjet head manufacturing process according to the modification example of the first embodiment. 
         FIG. 15  is a schematic sectional view showing the head chip in the present embodiment. 
         FIG. 16  is a flowchart explaining an inkjet head manufacturing process in a second embodiment. 
         FIG. 17  is a flowchart explaining an inkjet head manufacturing process according to a modification example of the second embodiment. 
     
    
    
     EMBODIMENTS FOR CARRYING OUT THE INVENTION 
     Hereinafter, embodiments according to an inkjet head manufacturing method, an inkjet recording device manufacturing method, an inkjet head, and an inkjet recording device of the present invention will be described with reference to the drawings. 
     First Embodiment 
       FIG. 1  is a view showing a perspective configuration of an inkjet recording device  1  which is a first embodiment of the present invention. 
     The inkjet recording device  1  includes a conveyance unit  2 , a head unit  3 , and the like. 
     The conveyance unit  2  includes a ring-shaped conveyance belt  2   c  the inside of which is supported by two conveyance rollers  2   a  and  2   b  which rotate around a rotation shaft extending in the X direction of  FIG. 1 . The conveyance unit  2  conveys a recording medium M in a movement direction of the conveyance belt  2   c  (conveyance direction; Y direction in  FIG. 1 ) by the conveyance roller  2   a  rotating according to the operation of a conveyance motor not shown in the drawings to cause the conveyance belt  2   c  to perform a rotary movement, in a state in which the recording medium M is placed on the conveyance surface of the conveyance belt  2   c.    
     The recording medium M can be a sheet of paper which is cut to have a fixed size. The recording medium M is supplied onto the conveyance belt  2   c  by a sheet feeding device not shown in the drawings, and ejected to a predetermined sheet ejection unit from the conveyance belt  2   c  after the ink is ejected from the head unit  3  to record an image. As the recording medium M, roll paper may be used. As the recording medium M, in addition to paper such as plain paper and coated paper, various mediums such as fabric or sheet resin that allows ink attached to the surface thereof to be fixed can be used. 
     The head unit  3  ejects ink at an appropriate timing based on image data to the recording medium M conveyed by the conveyance unit  2 , to record an image. In the inkjet recording device  1  in the present embodiment, four head units  3  respectively corresponding to four colors of yellow (Y), magenta (M), cyan (C), and black (K) are arranged at predetermined intervals in the order of Y, M, C, and K colors from the upstream side in the conveyance direction of recording medium M. The number of head units  3  may be three or less, or five or more. 
       FIG. 2  is a schematic view showing the configuration of head unit  3 , and is a plan view seen from the side opposing the conveyance surface of the conveyance belt  2   c  of the head unit  3 . The head unit  3  has a plate base portion  3   a  and a plurality of (eight in the embodiment) inkjet heads  100  which are fixed to the base portion  3   a  in a state in which the inkjet heads  100  are fitted to through holes provided in the base portion  3   a . The inkjet heads  100  are fixed to the base portion  3   a  in a state in which nozzle opening surface in which openings of nozzles  111  are provided are exposed toward −Z direction from the through holes of the base portion  3   a.    
     In each of the inkjet heads  100 , a plurality of nozzles  111  are arranged at equal intervals in a direction (width direction orthogonal to the conveyance direction in the present embodiment, that is, X direction) crossing the conveyance direction of recording medium M. In detail, each of the inkjet heads  100  has a row of nozzles  111  (nozzle row) which are one-dimensionally arranged at equal intervals in the X direction. 
     The inkjet head  100  may have a plurality of nozzle rows. In this case, the plurality of nozzle rows are disposed at positions in the X direction shifted from each other so that the positions in the X direction of the nozzles  111  do not match. 
     The eight inkjet heads  100  in the head unit  3  are arranged in a staggered manner so that the arrangement range in the X direction of the nozzles  111  is continuous. The arrangement range in the X direction of the nozzles  111  included in the head unit  3  cover the width in the X direction of the region where the image can be recorded in the recording medium M conveyed by the conveyance belt  2   c . The head unit  3  is used with its position fixed at the time of image recording, and the head unit  3  records an image with a single pass method by ejecting ink from the nozzles  111  to respective positions at predetermined intervals in the conveyance direction (intervals in conveyance direction) in accordance with the conveyance of recording medium M. 
       FIG. 3  is a perspective view of the inkjet head  100 . 
     The inkjet head  100  includes a housing  101  and an exterior member  102  which is fitted to the housing  101  at the lower end of the housing  101 . The main components are contained inside the housing  101  and the exterior member  102 . Among them, in the exterior member  102 , an inlet  103   a  to which ink is supplied from outside, and outlets  103   b  and  103   c  from which ink is discharged to outside are provided. A plurality of attachment holes  104  for attaching the inkjet head  100  to the base portion  3   a  in the head unit  3  are provided in the exterior member  102 . 
       FIG. 4  is an exploded perspective view of the main parts of the inkjet head  100 . 
       FIG. 4  shows main components contained inside the exterior member  102  among the components of the inkjet head  100 . To be specific,  FIG. 4  shows a head chip  10  having a nozzle substrate  11 , a flow path spacer substrate  12  (flow path substrate) and a pressure chamber substrate  13 , a wiring substrate  14  which is fixed to the head chip  10 , and an FPC  20  (Flexible Printed Circuit) which is electrically connected to the wiring substrate  14 .  FIG. 4  shows each component such that the nozzle opening surface  112  of the inkjet head  100  is located on the upper side, that is, such that the image is shown upside down with respect to  FIG. 2 . Hereinafter, the surface on −Z direction side of each substrate will also be referred to as an upper surface, and the surface on +Z direction side of each substrate will also be referred to as a lower surface. 
     The head chip  10  has a structure accumulating layers of the nozzle substrate  11  including nozzles  111 , flow path spacer substrate  12  including ink flow paths  121  which communicate with the nozzles  111 , and pressure chamber substrate  13  including pressure chambers  131  which communicate with the nozzles  111  via the ink flow paths  121  and the like. All of the nozzle substrate  11 , flow path spacer substrate  12 , pressure chamber substrate  13  and wiring substrate  14  are plate members in nearly quadrangular prism shapes which are long in the X direction. 
     The material of pressure chamber substrate  13  is a piezoelectric body (member which is deformed in accordance with voltage application) of ceramics. The examples of such a piezoelectric body include PZT (lead zirconate titanate), lithium niobate, barium titanate, lead titanate, lead metaniobate, and the like. PZT is used for the pressure chamber substrate  13  in the present embodiment. 
     The pressure chambers  131  in the pressure chamber substrate  13  are through holes which are respectively provided at the positions matching the positions of nozzles  111  when seen from the Z direction in the pressure chamber substrate  13 . The cross section of each of the pressure chambers  131  along the X-Y plane is a rectangle which is long in the Y direction. In the pressure chamber substrate  13  in the present embodiment, the plurality of pressure chambers  131  are arranged to form a row along the X direction. 
     The ink is supplied via an ink supply port provided on the wiring substrate  14  to each of the pressure chambers  131 . Each of the pressure chambers  131  is communicating with the nozzle  111  via the ink flow path  121  of the flow path spacer substrate  12 . 
       FIG. 5  is an enlarged plan view of the pressure chamber substrate  13 .  FIG. 5  is a plan view of the portion around the pressure chambers  131  in the pressure chamber substrate  13  seen from the lower side (from +Z direction side) of  FIG. 4 . 
     As shown in  FIG. 5 , each pressure chambers  131  which are adjacent in the X direction are partitioned by a dividing wall  134  of the piezoelectric body. Metal drive electrodes  133  are provided on inner wall surfaces of the dividing wall  134  of each pressure chambers  131 . Metal connection electrodes  135  which are electrically connected to the drive electrodes  133  are provided in regions around the +Y direction side of the openings of pressure chambers  131  in the surface of the pressure chamber substrate  13 . The connection electrodes  135  are electrically connected to an external drive circuit via wirings  143  of the wiring substrate  14  shown in  FIG. 4 , and wirings  21  of the FPC  20 . 
     In the pressure chamber substrate  13 , the pressure of ink inside each of the pressure chambers  131  changes by the dividing wall  134  repeating the shear mode type displacement according to the drive signal applied to the drive electrode  133  via the connection electrode  135 . In response to this change in the pressure, the ink in the pressure chamber  131  is ejected from the nozzle  111  via the ink flow path  121 . That is, the head chip  10  in the present embodiment is a head chip which performs shear mode type ink ejection. 
     Instead of the pressure chamber  131 , an air chamber not supplying ink may be provided at an every other position for the pressure chamber  131  in the X direction in  FIG. 5 . By having such a configuration, it is possible to prevent the deformation of dividing wall  134  adjacent to one pressure chamber  131  from influencing the other pressure chamber  131 . 
     As shown in  FIG. 4 , the pressure chamber substrate  13  includes common ink discharge flow paths  132  to which ink partially inflows back, the ink not having been ejected from the nozzles  111  in the ink supplied to the ink flow paths  121  of the flow path spacer substrate  12  from the pressure chambers  131 . The two common ink discharge flow paths  132  are provided at the respective positions having the plurality of pressure chambers  131  therebetween in the Y direction. Each of the common ink discharge flow paths  132  includes, near the end in the Y direction, a groove-like horizontal common discharge flow path  132   a  extending in the X direction along the surface on the flow path spacer substrate  12  side of the pressure chamber substrate  13  and a vertical common discharge flow path  132   b  penetrating in the Z direction the pressure chamber substrate  13  and connected to the horizontal common discharge flow path  132   a  at the end on the +X direction side of the horizontal common discharge flow path  132   a . The ink which inflows back to the horizontal common discharge flow path  132   a  from the ink flow paths  121  of the flow path spacer substrate  12  is discharged outside the inkjet head  100  from the outlet  103   b  (or outlet  103   c ) through the vertical common discharge flow path  132   b  and the discharge hole  142  provided in the wiring substrate  14 . 
     The flow path spacer substrate  12  is a plate member in a rectangular parallelepiped shape having a size which is nearly equal to the pressure chamber substrate  13  in a plan view. The flow path spacer substrate  12  is bonded (fixed) via an adhesive to the upper surface of the pressure chamber substrate  13 . The flow path spacer substrate  12  in the present embodiment is formed of a silicon substrate. Though not particularly limited, the thickness of the flow path spacer substrate  12  is approximately several hundred μm. 
     Each of the ink flow paths  121  provided in the flow path spacer substrate  12  includes: a through flow path  122  penetrating the flow path spacer substrate  12  at a position matching the position where the pressure chamber  131  is formed when seen from the Z direction; and an individual ink discharge flow path  123  diverging from the through flow path  122 . 
     The shape of the cross section parallel to the X-Y plane of the through flow path  122  is a rectangle which is nearly same as the shape of the cross section of the pressure chamber  131 . The opening on the pressure chamber substrate  13  side of the through flow path  122  is connected to the pressure chamber  131 , and the opening on the nozzle substrate  11  side is connected to the nozzle  111 . 
     The individual ink discharge flow path  123  includes: a pair of horizontal individual discharge flow paths  123   a  in groove shapes which are respectively extending in the +Y direction and the −Y direction along the surface of the flow path spacer substrate  12  from the opening on the nozzle substrate  11  side of the through flow path  122 ; and vertical individual discharge flow paths  123   b  provided to penetrate the flow path spacer substrate  12  from the respective ends of the horizontal individual discharge flow paths  123   a . The openings on the pressure chamber substrate  13  side of the vertical individual discharge flow paths  123   b  are respectively connected to the horizontal common discharge flow paths  132   a  of the common ink discharge flow path  132 . Accordingly, the individual ink discharge flow path  123  leads the ink, which flows in the horizontal individual discharge flow path  123   a  from the through flow path  122 , to the common ink discharge flow path  132  via the vertical individual discharge flow path  123   b.    
     In such a way, the individual ink discharge flow paths  123  provided in the flow path spacer substrate  12  and the common ink discharge flow paths  132  provided in the pressure chamber substrate  13  form the ink discharge flow paths for discharging the ink which was not ejected from the nozzles  111  in the ink inside the pressure chambers  131 . 
     The four faces which connect the upper surface and the lower surface of the flow path spacer substrate  12  to each other and in which the opening of the ink flow path  121  is not provided are hereinafter referred to as lateral surfaces. 
     The flow path spacer substrate  12  is manufactured by splitting a composite flow path spacer substrate  12 M (composite substrate) ( FIG. 11A ) into the flow path spacer substrates  12  (splitting into individual pieces), the composite flow path spacer substrate  12 M including a plurality of regions which forms the flow path spacer substrates  12  by being split. Thus, at least a part of the four lateral surfaces of the flow path spacer substrate  12  is a split face (cross section) which was generated when the composite flow path spacer substrate  12 M was split into flow path spacer substrates  12 . The split face of the flow path spacer substrate  12  is exposed in the surface of the head chip  10 . Hereinafter, the split face exposed in the surface of the head chip  10  is referred to as an exposed face  12   a.    
     The nozzle substrate  11  is a silicon substrate in which the nozzles  111  that are holes running through the thickness direction (Z direction) are provided in a line. The nozzles  111  are provided at respective positions matching the positions of through flow paths  122  in the ink flow paths  121  of the flow path spacer substrate  12  when seen from the Z direction. The planar shape of the nozzle substrate  11  is nearly same as the shape of the flow path spacer substrate  12  and the pressure chamber substrate  13 . The upper surface of the nozzle substrate  11  forms the nozzle opening surface  112  of the inkjet head  100 . The thickness of the nozzle substrate  11  is approximately several tens of μm to several hundreds of μm, for example. 
     The inner wall surface of each of the nozzles  111  may have a taper shape such that the cross sectional area vertical to the Z direction which is closer to the opening on the ink ejection side is smaller. The nozzle substrate  11  may be configured by including resin such as polyimide, metal or the like. It is desirable that the opening surface  112  of the nozzle substrate  11  is provided with a water-repellent film including a liquid repellent material such as fluorine resin particles. By providing the water-repellent film, it is possible to suppress the adhering of ink and foreign substances to the nozzle opening surface  112 , and suppress the occurrence of ink ejection defects caused by the adhering of ink, foreign substances and the like. 
     The nozzle substrate  11  is manufactured by splitting a composite nozzle substrate  11 M (composite substrate) ( FIG. 10A ) into nozzle substrates  11 , the composite nozzle substrate  11 M having a plurality of regions which forms nozzle substrates  11  by being split, similarly to the flow path spacer substrate  12 . Thus, at least a part of the four lateral surfaces connecting the upper surface and the lower surface of the nozzle substrate  11  is a split face which was generated when the composite nozzle substrate  11 M was split into the nozzle substrates  11 . Hereinafter, the split face of the nozzle substrate  11  exposed in the surface of the head chip  10  is referred to as an exposed face  11   a.    
     It is preferable that the wiring substrate  14  is a substrate in a flat plate shape having an area larger than an area of the pressure chamber substrate  13  from the view point of securing the bonding region with the pressure chamber substrate  13 , and the wiring substrate  14  is bonded to the lower surface of the pressure chamber substrate  13  via an adhesive. As the wiring substrate  14 , a substrate of glass, ceramics, silicon, plastic or the like can be used, for example. 
     The wiring substrate  14  includes a plurality of ink supply ports  141  at positions matching the positions of the plurality of pressure chambers  131  of the pressure chamber substrate  13  when seen from the Z direction, and a pair of discharge holes  142  are provided at positions matching the positions of the pair of vertical common discharge flow paths  132   b . A plurality of wirings  143  extending toward the end of the wiring substrate  14  from the respective ends of the plurality of ink supply ports  141  are provided on the bonding surface between the wiring substrate  14  and the pressure chamber substrate  13 . 
     An ink manifold (common ink chamber) not shown in the drawings is connected to the lower surface of the wiring substrate  14 , and ink is supplied to the ink supply ports  141  from the ink manifold. 
     The wiring substrate  14  is manufactured by splitting a composite wiring substrate (composite substrate) into wiring substrates  14 , the composite wiring substrate having a plurality of regions which forms the wiring substrates  14  by being split, similarly to the flow spacer substrate  12 . Thus, at least a part of the four lateral surfaces (two faces on the +Y direction side and −Y direction side in the embodiment) connecting the upper surface and the lower surface of the wiring substrate  14  is a split face which was generated when the composite wiring substrate was split into the wiring substrates  14 . Hereinafter, the split face of the wiring substrate  14  exposed in the surface of the head chip  10  is referred to as the exposed face  14   a.    
     The pressure chamber substrate  13  and the wiring substrate  14  are bonded via an electrical conductive adhesive containing electrical conductive particles. Thus, the connection electrodes  135  on the surface of the pressure chamber substrate  13  and the wirings  143  on the wiring substrate  14  are electrically connected via the electrical conductive particles. 
     The FPC  20  is connected to the end of the wiring substrate  14  provided with the wirings  143  via the ACF (Anisotropic Conductive Film), for example. By this connection, the plurality of wirings  143  of the wiring substrate  14  are electrically connected to the plurality of wirings  21  on the FPC  20  such that the wirings  143  correspond to the respective wirings  21 . 
       FIG. 6  is a schematic sectional view of a portion including the head ship  10  in the inkjet head  100 .  FIG. 6  shows a cross section vertical to the X direction of the inkjet head  100 .  FIG. 6  draws exaggerating the thicknesses of the nozzle substrate  11  and the flow path spacer substrate  12  for convenience of explanation. 
     As shown in  FIG. 6 , the exterior member  102  is provided to cover a part of the head chip  10  with the nozzle opening surface  112  of the nozzle substrate  11  in the head chip  10  exposed. The exterior member  102  is bonded to the head chip  10  via an adhesive  80 . 
     In detail, the exterior member  102  includes a top board  1021  (recess formed portion), a lateral wall  1022  and a sealing plate  1023 . Though the material of each component of the exterior member  102  is not particularly limited, various resins such as PPS resin, metal, alloy or the like which is excellent in the mechanical strength and resistance to ink can be used. 
     The top board  1021  is a rectangular plate member having a shape in which the upper surface (hereinafter, referred to as recess formed surface  1021   a ) has a recessed shape at the central portion to have a recess R. An exposing through hole  1021   b  (through hole) having an opening at the deepest part of the recess R is provided in the top board  1021 . The head chip  10  is provided in a state in which the portion, which includes the nozzle opening surface  112  and at least a part of the split faces (exposed faces  12   a ) generated in splitting into the individual pieces of flow path spacer substrates  12 , protrude outside the exterior member  102  in the range within the recess R from the opening of the exposing through hole  1021   b  of the top board  1021 . By such a configuration, it is possible to facilitate the contact of wiping member with the nozzle opening surface  112  when the recess formed surface  1021   a  of the top board  1021  and the nozzle opening surface  112  are wiped with the wiping member such as a wiping cloth. 
     Moreover, since the protruding range of the head chip  10  is within the recess R, the nozzle opening surface  112  of the head chip  10  is provided at the position deeper toward the +Z direction side than the face of the portion excluding the recess R in the recess formed surface  1021   a  in the top board  1021 . Thus, it is possible to prevent the nozzle opening surface  112  from easily contacting the recording medium M or foreign substances on the conveyance surface of the conveyance belt  2   c.    
     The lateral wall  1022  is a plate member which is connected to the outer circumference of the top board  1021  and covers the lateral side of the head chip  10 . A member separate from the top board  1021  may be used for the lateral wall  1022 , or the lateral wall  1022  may be integrally provided with the top board  1021 . 
     The sealing plate  1023  is a plate member which is connected to the exposing through hole  1021   b  of the top board  1021 , and extending along the lateral surfaces of the flow path spacer substrate  12  and the pressure chamber substrate  13  in the head chip  10 . A member separate from the top board  1021  may be used for the sealing plate  1023 , or the sealing plate  1023  may be integrally provided with the top board  1021 . 
     The inner circumferential surface of the sealing plate  1023  (surface facing the flow path spacer substrate  12  and the pressure chamber substrate  13 ) and the lateral surfaces of the flow path spacer substrate  12  and the pressure chamber substrate  13  are bonded to each other via the adhesive  80 . Though not particularly limited, a known epoxy type adhesive, for example, can be used as the material of the adhesive  80 . By such a configuration, the gap between the exterior member  102  and the head chip  10  is sealed. That is, the adhesive  80  also achieves the role as a sealing member which prevents the entrance of ink from outside. 
     The adhesive  80  coming around the nozzle opening surface  112  influences the ink ejection from the nozzles  111  and leads to the occurrence of trouble that the recording medium M facing the nozzle opening surface  112  contact the adhesive  80 . Thus, it is desirable that the adhesive  80  is provided only on the lateral surfaces of the head chip  10 , and thus, the adhesive  80  is provided in the range excluding a predetermined neighboring range from the upper ends of the lateral surfaces of the head chip  10 . In detail, the adhesive  80  is provided in each predetermined region not covering the range from the lateral surface of the nozzle substrate  11  to a part of the exposed face  12   a  of the flow path spacer substrate  12  in each of the lateral surfaces of the head ship  10 . Accordingly, a part of each of the exposed faces  12   a  of the flow path spacer substrate  12  is exposed from the exterior member  102 . 
       FIG. 7  is a schematic cross sectional view showing a part of  FIG. 6  by enlarging the part.  FIG. 7  shows the ink flow path  121  in the flow path spacer substrate  12 , the pressure chamber  131  in the pressure chamber substrate  13 , and the ink supply port  141  in the wiring substrate  14 . 
     As shown in  FIG. 7 , a first protective film  71   a  is provided on the surface of the nozzle substrate  11  and the inner wall surface of the nozzle  111 . A first protective film  71   b  is provided on the surface of the flow path spacer substrate  12  and the inner wall surface of the ink flow path  121 . A first protective film  71   c  is provided on the surface of the wiring substrate  14  and the inner wall surface of the ink supply port  141 . When a water-repellent film is provided on the nozzle opening surface  112  of the nozzle substrate  11 , the water-repellent film is formed to be overlaid on the first protective film  71   a.    
     The first protective films  71   a ,  71   b  and  71   c  are not formed on any of the split face (exposed face  11   a ) which was generated at the time of splitting into the nozzle substrates  11  (splitting into individual pieces) among the lateral surfaces of the nozzle substrate  11 , the split face (exposed face  12   a ) which was generated at the time of splitting into the flow path spacer substrates  12  (splitting into individual pieces) among the lateral surfaces of the flow path spacer substrate  12 , and the split face (exposed face  14   a ) which was generated at the time of splitting into the wiring substrates  14  (splitting into individual pieces) among the lateral surfaces of the wiring substrate  14 . This is because the first protective film  71   a ,  71   b  or  71   c  is formed on each composite substrate having a plurality of regions which forms the nozzle substrates  11 , the flow path spacer substrates  12  or the wiring substrates  14 , and thereafter the composite substrates are split into the nozzle substrates  11 , the flow path spacer substrates  12  and the wiring substrates  14 . 
     Though the first protective films  71   a ,  71   b  and  71   c  are not particularly limited, for example, an organic protective film such as polyparaxylylene, or a protective film formed of an inorganic oxide or an inorganic nitride including at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta and Si can be used. By providing such first protective films  71   a ,  71   b  and  71   c , it is possible to suppress the occurrence of trouble that the nozzles  111 , the ink flow paths  121  and the ink supply ports  141  are corroded by ink, and trouble that the ink adhering to the surfaces of the nozzle substrate  11 , the flow spacer substrate  12  and the wiring substrate  14  enters the head chip  10  and erodes the flow paths. 
     In addition, as shown in  FIG. 7 , second protective films  72  which are not integrally provided with the first protective films  71   a ,  71   b  and  71   c  are provided on the surface of the layered substrate (hereinafter, referred to as an intermediate layered substrate) which includes the flow spacer substrate  12 , the pressure chamber substrate  13  and the wiring substrate  14 , and the internal wall surfaces of the ink flow path  121 , the pressure chamber  131 , the common ink discharge flow path  132 , the ink supply port  141  and the discharge hole  142  inside the intermediate layered substrate. Accordingly, the exposed face  12   a  which is not provided with the first protective film  71   b  in the flow path spacer substrate  12  and the exposed face  14   a  which is not provided with the first protective film  71   c  in the wiring substrate  14  are covered with the second protective film  72 . 
     Though the second protective film  72  is not particularly limited, for example, an organic protective film such as polyparaxylylene, or a protective film formed of an inorganic oxide or an inorganic nitride including at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta and Si, similarly to the first protective films  71   a ,  71   b  and  71   c.    
     By providing the second protective film  72  in such a way, it is possible to particularly protect the exposed face  12   a  of the flow path spacer substrate  12  which is not provided with the first protective film  71   b  due to the splitting into individual pieces and the exposed face  14   a  of the wiring substrate  14  which is not provided with the first protective film  71   c  due to the splitting into individual pieces. As mentioned above, ink particularly from outside easily adheres to the exposed face  12   a  of the flow path spacer substrate  12  since a part thereof is exposed to the outside of the exterior member  102  without being sealed with the adhesive  80 . However, by providing the second protective film  72  on the exposed face  12   a , it is possible to suppress the occurrence of trouble that the ink enters through an unintended path into the head chip  10  (into the flow path spacer substrate  12 ) even when the ink adheres to the exposed face  12   a.    
     Moreover, it is possible to protect, with the second protective film  72 , the surface of the pressure chamber substrate  13  and the inner wall surfaces of the pressure chamber  131  and the common ink discharge flow path  132 , on which the first protective film  71  is not provided. 
       FIGS. 6 and 7  explains by using an example of providing the adhesive  80  to only a part of the exposed face  12   a  of the flow path spacer substrate  12 , and exposing another part of the exposed face  12   a  outside the exterior member  102 , however, the present invention is not limited to this. For example, as shown in  FIG. 8 , the adhesive  80  may be provided in a region not covering the exposed face  12   a  of the flow path spacer substrate  12 , so that the entire exposed face  12   a  of the flow path spacer substrate  12  is exposed to the outside of the exterior member  102 . That is, a predetermined region excluding at least a part or whole of the exposed face  12   a  of the flow path spacer substrate  12  in the surface of the head chip  10  may be bonded to the exterior member  102  with the adhesive  80 . Since the thickness of the flow path spacer substrate  12  and the nozzle substrate  11  is equal to or less than several hundred μm, which is small, the configuration shown in  FIG. 8  may be necessary in order to surely prevent the adhesive  80  from reaching the nozzle opening surface  112 . 
     Alternatively, the entire exposed face  12   a  of the flow path spacer substrate  12  may be sealed with the adhesive  80 . Also in this case, the ink may enter the interface between the flow path spacer substrate  12  and the adhesive  80  due to the bad bonding, deterioration of the adhesive  80  and the like. However, by providing the second protective film  72  on the exposed face  12   a  of the flow path spacer substrate  12 , it is possible to suppress the occurrence of trouble that the ink enters inside the flow path spacer substrate  12 . 
     Next, the manufacturing method of the inkjet head  100  and the manufacturing process related to the manufacturing method will be described. 
       FIG. 9  is a flowchart explaining the manufacturing process of the inkjet head  100 . 
     In the manufacturing process of the inkjet head  100  in the present embodiment, the composite nozzle substrate  11 M having a plurality of regions which forms the nozzle substrates  11  by being split is first manufactured (step S 101 ). That is, as shown in  FIG. 10A , the composite nozzle substrate  11 M is manufactured by forming the nozzles  111  corresponding to the plurality of nozzle substrates  11  in a silicon substrate. 
     Next, the first protective film  71   a  is formed on the surface of the composite nozzle substrate  11 M and the inner wall surfaces of the nozzles  111  (step S 102 ) ( FIG. 10B ). In this step, for example, the vapor deposition method can be used when polyparaxylylene is used as the first protective film  71   a . When an inorganic oxide or an inorganic nitride including at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta and Si is used as the protective film  71   a , the CVD method, sputtering method and the like can be used. 
     Next, by dividing the composite nozzle substrate  11 M at dividing positions P 1  in  FIG. 10B , the composite nozzle substrate  11 M is split into a plurality of nozzle substrates  11  (step S 103 ) ( FIG. 10C ). In this step, any of various splitting methods such as dicing with a blade, cutting with a laser cutter, and scribe break (method combining the scribe of providing a crack in the surface with a knife or the like and the break of extending the crack to break) can be used, for example. 
     The nozzle substrate  11  manufactured in step S 103  is in a state in which the first protective film  71   a  is not formed on the split faces (exposed faces  11   a ) generated by the splitting. 
     The processes of the above steps S 101  to S 103  are also hereinafter referred to as the nozzle substrate manufacturing process. 
     Next, the composite flow path spacer substrate  12 M having a plurality of regions which forms the flow path spacer substrates  12  by being split is manufactured (step S 104 : composite substrate manufacturing). That is, as shown in  FIG. 11A , the composite flow path spacer substrate  12 M is manufactured by forming the ink flow paths  121  corresponding to the plurality of flow path spacer substrates  12  in a silicon substrate. 
     Next, the first protective film  71   b  is formed on the surface of the composite flow path spacer substrate  12 M and the inner wall surfaces of the ink flow paths  121  (step S 105 : first protective film forming) ( FIG. 11B ). In this step, the film forming method similar to that of the above-mentioned step S 102  can be used. 
     Next, the composite flow path spacer substrate  12 M is split into the plurality of flow path spacer substrates  12  by dividing the composite flow path spacer substrate  12 M at dividing positions P 2  in  FIG. 11B  (step S 106 : splitting) ( FIG. 11C ). In this step, the splitting method similar to that of the above-mentioned step S 103  can be used. 
     The flow path spacer substrate  12  manufactured in step S 106  is in a state in which the first protective film  71   b  is not formed on the split faces (exposed faces  12   a ) generated by the splitting. 
     The processes of the above steps S 104  to S 106  are also hereinafter referred to as the flow path spacer substrate manufacturing process. 
     Next, the composite wiring substrate having a plurality of regions which forms the wiring substrates  14  by being split is manufactured (step S 107 ). That is, the composite wiring substrate is manufactured by forming the ink supply ports  141 , discharge holes  142  and wirings  143  corresponding to the plurality of wiring substrates  14  in a silicon substrate. As for the steps S 107  to S 109  related to the manufacturing of wiring substrate  14 , the description of sectional view for the steps is omitted. 
     Next, the first protective film  71   c  is formed on the surface of the composite wiring substrate and the inner wall surfaces of the ink supply ports  141  and the inner wall surfaces of the discharge holes  142  (step S 108 ). In this step, the film forming method similar to that of the above-mentioned step S 102  can be used. 
     Next, the composite wiring substrate is split into the plurality of wiring substrates  14  by dividing the composite wiring substrate at predetermined dividing positions (step S 109 ). In this step, the splitting method similar to that of the above-mentioned step S 103  can be used. 
     The wiring substrate  14  manufactured in step S 109  is in a state in which the first protective film  71   c  is not formed on the split faces (exposed face  14   a  ( FIG. 7 )) generated by the splitting. 
     The processes of the above steps S 107  to S 109  are also hereinafter referred to as the wiring substrate manufacturing process. 
     Next, the pressure chamber substrate  13  is manufactured by forming the pressure chambers  131 , the common ink discharge flow paths  132 , the drive electrodes  133  and the connection electrodes  135  in the substrate formed of a piezoelectric body (step S 110 ). In this step S 110 , similarly to the above-mentioned other substrates, a composite substrate having a plurality of regions which forms pressure chamber substrates  13  by being split may be divided into individual pieces of the plurality of pressure chamber substrates  13 , or each of the pressure chamber substrates  13  may be manufactured separately. The process in this step S 110  is also hereinafter referred to as the pressure chamber substrate manufacturing process. 
     The orders of executing the above mentioned nozzle substrate manufacturing process, flow path spacer substrate manufacturing process, wiring substrate manufacturing process and the pressure chamber substrate manufacturing process may be reversed to each other, or at least parts of the processes may be performed parallel to each other. 
     Next, as shown in  FIG. 12A , the intermediate layered substrate is manufactured by attaching the flow path spacer substrate  12 , the pressure chamber substrate  13  and the wiring substrate  14  to each other via the adhesive (step S 111 ). 
     Next, as shown in  FIG. 12B , the second protective film  72  is formed on the surface of the intermediate layered substrate, and the inner wall surfaces of the ink flow paths  121 , pressure chambers  131 , the common ink discharge flow paths  132 , the ink supply ports  141  and the discharge holes  142  (step S 112 : second protective film forming). In this step, the film forming method similar to that of the above-mentioned step S 102  can be used. 
     Next, as shown in  FIG. 12C , the head chip  10  is manufactured by fixing the nozzle substrate  11  to the intermediate layered substrate via the adhesive (step S 113 : nozzle substrate fixing). The obtained head chip  10  and the exterior member  102  are bonded via the adhesive  80  (step S 114 : exterior member bonding), the other components are incorporated into the housing  101  and the exterior member  102 , and then the inkjet head  100  is completed. 
     Modification Example 
     A modification example of the first embodiment will be described. The modification example is different from the above embodiment in the surface where the second protective film  72  is formed. Hereinafter, the difference from the above embodiment will be described. 
       FIG. 13  is an enlarged schematic sectional view of the inkjet head  100  according to the modification example. 
     As shown in this figure, in the modification example, the second protective film  72  is formed on the entire surface of the layered substrate including the head chip formed of the nozzle substrate  11 , the flow path spacer substrate  12  and the pressure chamber substrate  13 , and the wiring substrate  14 . Accordingly, the second protective film  72  is also formed on the inner wall surfaces of the nozzles  111  and the split faces (exposed faces  11   a ) generated by the splitting of the composite nozzle substrate  11 M among the lateral surfaces of the nozzle substrate  11 . 
     When a water-repellent film is provided to the nozzle opening surface  112  in the modification example, the water-repellent film may be formed to be overlaid on the second protective film  72  provided on the nozzle opening surface  112  of the nozzle substrate  11 . 
       FIG. 14  is a flowchart showing a manufacturing process of the inkjet head  100  in the modification example. 
     The flowchart in  FIG. 14  is obtained by changing the steps S 111  and S 112  in the flowchart in  FIG. 9  of the above embodiment to steps S 111   a  and S 112   a  and deleting the step S 113 . Hereinafter, the difference from the flowchart in  FIG. 9  will be described. 
     In the manufacturing process of the inkjet head  100  in the modification example, after the nozzle substrate manufacturing process, the flow path spacer substrate manufacturing process, the wiring substrate manufacturing process and the pressure chamber substrate manufacturing process (step S 101  to S 110 ) are finished, the layered substrate is manufactured by attaching the nozzle substrate  11 , the flow path spacer substrate  12 , the pressure chamber substrate  13  and the wiring substrate  14  to each other via the adhesive (step S 111   a : nozzle substrate fixing). Then, the second protective film  72  is formed on the obtained layered substrate (step S 112   a : second protective film forming), thereafter, the exterior ember  102  is bonded to the head chip  10  (step S 114 : exterior member bonding), and the inkjet head  100  is completed. 
     As described above, the manufacturing method of the inkjet head  100  in the present embodiment is a manufacturing method for an inkjet head  100  that includes a head chip  10  including: nozzles  111  that eject ink; and a flow path spacer substrate  12  including ink flow paths  121  which communicate with the nozzles  111  and through which the ink flows, the method including: composite substrate manufacturing that is manufacturing a composite flow path spacer substrate  12 M including a plurality of regions which forms flow path spacer substrates  12  by being split, each of the flow path spacer substrates  12  being the flow path spacer substrate  12 ; first protective film forming that is forming a first protective film  71   a  on a surface of the composite flow path spacer substrate  12 M and inner wall surfaces of the ink flow paths  121 ; 
     splitting that is splitting the composite flow path spacer substrate  12 M into the flow path spacer substrates  12 ; and second protective film forming that is forming a second protective film  72  on at least exposed faces  12   a  in split faces of the flow path spacer substrates  12  generated in the splitting, the exposed faces  12   a  being exposed in a surface of the head chip  10 . 
     Though the first protective film  71   a  is not provided on the split faces of the flow path spacer substrates  12  generated in the above splitting, the exposed faces  12   a  can be protected by providing the second protective film  72  on the split faces (exposed faces  12   a ) exposed in the surface of the head chip  10  as in the manufacturing method of the present embodiment. Thus, it is possible to suppress the occurrence of trouble that the ink adhering to any split face corrodes the flow path spacer substrate  12  and enters the flow path spacer substrate  12  even when the split face of the flow path spacer substrate  12  generated by the splitting into individual pieces is exposed in the surface of the head chip  10 . Furthermore, according to the above manufacturing method, since it is possible to cover the inner wall surfaces of the ink flow paths  121  of the flow path spacer substrate  12  with the first protective film  71   a , it is possible to suppress the occurrence of trouble that any ink flow path  121  is corroded by the ink flowing through the ink flow path  121 . 
     Though the above description describes the effect focusing on the flow path spacer substrate  12 , the above embodiment also obtains the same effect for the wiring substrate  14 . That is, also in the wiring substrate  14 , since exposed faces  14   a  which are the split faces exposed in the surface of the head chip  10  can be covered with the second protective film  72 , it is possible to suppress the occurrence of trouble that the ink adhering to any split face corrodes the wiring substrate  14  even when the split face is exposed in the surface of the head chip  10 . Moreover, since the inner wall surfaces of the ink supply ports  141  and the discharge holes  142  as the ink flow path for the ink to flow can be covered with the first protective film  71   c , it is possible to suppress the occurrence of trouble that any of the ink supply ports  141  and the discharge holes  142  is corroded by the ink. 
     The head chip manufacturing includes nozzle substrate fixing that is directly or indirectly fixing a nozzle substrate  11 , in which openings of the nozzles  111  are provided, to the flow path spacer substrate  12  after the second protective film forming. By such a method, it is possible to efficiently manufacture the head chip  10  having the exposed faces  12   a  of the flow path spacer substrates  12  covered with the second protective film  72  when it is not necessary to provide the second protective film  72  on the surface of the nozzle substrate  11 . 
     The above modification example includes nozzle substrate fixing that is directly or indirectly fixing a nozzle substrate  11 , in which openings of the nozzles  111  are provided, to the flow path spacer substrate  12  before the second protective film forming, and the second protective film  72  is formed on a surface of an intermediate layered substrate including the flow path spacer substrate  12  and the nozzle substrate  11  in the second protective film forming. Thus, since the second protective film  72  is provided on the entire surface of the intermediate layered substrate, it is possible to more surely suppress the occurrence of trouble that the ink adhering from outside corrodes the portion corresponding to the intermediate layered substrate in the head chip  10 . That is, in the modification example, since the exposed face  11   a  exposed in the surface of the head chip  10  in the split face generated by the splitting into individual pieces is protected by the second protective film  72  also for the nozzle substrate  11 , it is possible to suppress the occurrence of trouble that the ink adhering to the exposed face  11   a  of the nozzle substrate  11  corrodes the nozzle substrate  11 . 
     The manufacturing method of inkjet head  100  in the above embodiment includes exterior member bonding that is bonding an exterior member  102  to the head chip  10  including the nozzle substrate  11  and the flow path spacer substrate  12  with an adhesive  80  after the second protective film forming, the exterior member  102  covering a part of the head chip  10  with a nozzle opening surface  112  exposed, and the nozzle opening surface  112  including the openings of the nozzles  111  in the nozzle substrate  11 . A predetermined region excluding at least a part or whole of each of the exposed faces  12   a  of the flow path spacer substrate  12  in the surface of the head chip is bonded to the exterior member  102  with the adhesive  80  in the exterior member bonding. 
     In this method, since a part of the exposed face  12   a  of the flow path spacer substrate  12  is exposed outside the exterior member  102  without being covered with the adhesive  80 , the ink easily adheres especially from outside. However, by providing the second protective film  72  on the exposed face  12   a , it is possible to suppress the occurrence of trouble that the flow path spacer substrate  12  is corroded by ink even when the ink adheres to the exposed face  12   a . The adhesive  80  coming to the nozzle opening surface  112  influences the ink ejection from the nozzles  111  and leads to the occurrence of trouble that the recording medium M facing the nozzle opening surface  112  contacts the adhesive  80 . However, bonding the predetermined region to the exterior member  102  with the adhesive  80  enables more surely providing the adhesive  80  to only the lateral surface of the head chip  10 , and thus it is possible to suppress the occurrence of the above trouble. 
     The exterior member  102  includes a recess R, an exposing through hole  1021   b  including an opening in an inner wall surface of the recess R is provided in the exterior member  102 , and in the exterior member bonding, the exterior member  102  is bonded to the head chip  10  such that a portion including the nozzle opening surface  112  and at least a part of the exposed face  12   a  of the flow path spacer substrate  12  in the head chip  10  protrudes outside the exterior member  102  from the opening of the exposing through hole  1021   b . Thus, it is possible to make a wiping member easily contact the nozzle opening surface  112  when the exterior member  102  (top board  1021 ) and the nozzle opening surface  112  are wiped with the wiping member. 
     The first protective film  71   a  is an inorganic oxide or an inorganic nitride that includes at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta and Si, or polyparaxylylene. By such a configuration, it is possible to more surely suppress the occurrence of trouble that the flow path spacer substrate  12  is corroded by the ink. 
     The second protective film  72  is an inorganic oxide or an inorganic nitride that includes at least one of Ti, Al, Zr, Cr, Hf, Ni, Ta and Si, or polyparaxylylene. By such a configuration, it is possible to more surely suppress the occurrence of trouble that the flow path spacer substrate  12  is corroded by the ink. 
     The flow path spacer substrate  12  is made of Si, metal or glass. Since the flow path spacer substrate  12  of such a configuration has a flat surface, it is possible to protect the surface without any gap with the first protective film  71   a  and the second protective film  72 , and process the ink flow path  121  easily. 
     The manufacturing method of the inkjet recording device  1  in the present embodiment includes the above manufacturing method of the inkjet head  100 . Thus, it is possible to manufacture the inkjet recording device  1  which does not easily cause the trouble that the flow path spacer substrate  12  of the inkjet head  100  is corroded by the ink. 
     The inkjet head  100  in the present embodiment is an inkjet head  100  which includes a head chip  10  including: nozzles  111  that eject ink; and a flow path spacer substrate  12  including ink flow paths  121  which communicate with the nozzles  111  and through which the ink flows. The flow path spacer substrate  12  includes lateral surfaces in which openings of the ink flow paths  121  are not provided, a first protective film  71   a  is provided on a surface excluding at least a part of the lateral surfaces of the flow path spacer substrate  12  and on inner wall surfaces of the ink flow paths  121 , at least a part of the portion where the first protective film  72   a  is not provided in the lateral surfaces is an exposed face  12   a  that is exposed in a surface of the head chip  10 , and a second protective film  72  that is not integrally formed with the first protective film  71   a  is provided on the exposed face  12   a.    
     By such a configuration, it is possible to suppress the occurrence of trouble that the ink flow path  121  is corroded by the ink since the first protective film  71   a  is provided on the flow path spacer substrate  12 . 
     Moreover, the first protective film  71   a  is not provided on at least a part of the lateral surfaces of the flow path spacer substrate  12 , and at least a part (exposed face  12   a ) of the portion where the first protective film  71   a  is not provided is exposed in the surface of the head chip  10 . Such an exposed face  12   a  is generated when the split face obtained by splitting the composite flow path spacer substrate  12 M into the flow path spacer substrates  12  is exposed in the surface of the head chip  10  as in the present embodiment. By the above configuration, since the second protective film  72  is provided on the exposed face  12   a , it is possible to suppress the occurrence of trouble that the ink adhering to the exposed face  12   a  of the flow path spacer substrate  12  corrodes the exposed face  12   a  and enters the flow path spacer substrate  12 . 
     Though the above description describes the effect focusing on the flow path spacer substrate  12 , the above embodiment also obtains the same effect for the wiring substrate  14 . 
     The portion where the first protective film  71   a  is not provided in the lateral surfaces of the flow path spacer substrate  12  is a split face that is generated in splitting a composite flow path spacer substrate  12 M into flow path spacer substrates  12 , the composite flow path spacer substrate  12 M including a plurality of regions which forms flow path spacer substrates  12  by being split. The second protective film  72   a  is provided on the exposed face  12   a , which is exposed in the surface of the head chip  10 , in the split face. Thus, it is possible to suppress the occurrence of trouble that the ink enters the flow path spacer substrate  12  when the flow path spacer substrate  12  is manufactured by splitting the composite flow path spacer substrate  12 M. 
     In the above modification example, the head chip  10  includes a nozzle substrate  11  in which openings of the nozzles  111  is provided, and the second protective film  72  is provided on the surface of an intermediate layered substrate including the flow path spacer substrate  12  and the nozzle substrate  11 . Thus, it is possible to more surely suppress the occurrence of trouble that the ink adhering from outside enters the portion corresponding to the intermediate layered substrate in the head chip  10 . 
     The head chip  10  includes the nozzle substrate  11  in which the openings of the nozzles  111  are provided, and the inkjet head  100  includes an exterior member  102  that covers a part of the head chip  10  with a nozzle opening surface  112  exposed, the nozzle opening surface  112  including the openings of the nozzles  111  in the nozzle substrate  11 . A predetermined region excluding at least a part or whole of the exposed face  12   a  of the flow path spacer substrate  12  in the surface of the head chip  10  is bonded to the exterior member  102  with an adhesive  80 . Thus, it is possible to surely protect the exposed face  12   a  of the flow path spacer substrate  12  which is exposed outside the exterior member  102  in such a configuration, with the second protective film  72 . It is also possible to more surely provide the adhesive  80  to only the lateral surface of the head chip  10 . 
     The exterior member  102  includes a recess R, an exposing through hole  1021   b  including an opening in an inner wall surface of the recess R is provided in the exterior member  102 , and a portion including the nozzle opening surface  112  and at least a part of the exposed face  12   a  of the flow path spacer substrate  12  in the head chip  10  protrudes outside the exterior member  102  from the opening of the exposing through hole  1021   b . By such a configuration, it is possible to make the wiping member easily contact the nozzle opening surface  112  when the exterior member  102  (top board  1021 ) and nozzle opening surface  112  are wiped with a wiping member such as a wiping cloth. 
     The inkjet recording device  1  in the present embodiment includes the above inkjet head  100 . Thus, it is possible to more surely suppress the corrosion of the flow path spacer substrate  12  by the ink. 
     Second Embodiment 
     Next, a second embodiment of the present invention will be described. The present embodiment is different from the first embodiment in the respect of using a head chip  10  of the so-called bend mode type which ejects ink by changing the vibration plate that forms the wall surface of pressure chamber by deformation of piezoelectric element. Hereinafter, the description will be made mainly for the difference from the first embodiment. 
       FIG. 15  is a schematic sectional view showing the head chip  10  in the present embodiment. 
     The head chip  10  in the present embodiment has a structure including a nozzle substrate  11 , a flow path spacer substrate  12 , a vibration substrate  30 , a piezoelectric element spacer substrate  40 , a wiring substrate  50  and a protective layer  60  which are layered in order from the lower side. 
     The nozzle substrate  11  includes a nozzle  111 , a large diameter portion  113  which is a hole communicating with the nozzle  111  and having a diameter larger than that of the nozzle  111 , and an individual ink discharge flow path  114  provided to diverge from the large diameter portion  113  and used for ink discharge. 
     The flow path spacer substrate  12  includes a large diameter portion  124  which is communicating with the large diameter portion  113 , a diaphragm portion  125  which is communicating with the individual ink discharge flow path  114 , and a common ink discharge flow path  126  which is communicating with the diaphragm portion  125 . 
     The common ink discharge flow path  126  extends in a direction orthogonal to the drawing, and is connected to a plurality of individual ink discharge flow paths  114  diverging from a plurality of nozzles  111 . The common ink discharge flow path  126  includes a through hole not shown in the drawings and running from the flow path spacer substrate  12  to the upper most surface of the head chip  10 , to allow the ink to be discharged from the through hole to the outlet  103   b  (or outlet  103   c ). 
     The vibration substrate  30  includes a pressure chamber layer  31  formed on a silicon substrate on which a pressure chamber  311  communicating with the large diameter portion  124  is provided, and a vibration plate  32 . The vibration plate  32  is layered on the upper surface of the pressure chamber layer  31  to cover the opening on the upper side of the pressure chamber  311 , and forms an upper wall portion of the pressure chamber  311 . In the vibration plate  32 , a through hole  321  communicating with the pressure chamber  311  and running in the upward direction is formed. 
     The piezoelectric element spacer substrate  40  is a substrate formed of  42  alloy and is a layer forming the space  41  for containing the piezoelectric elements  42  and the like between the vibration plate  32  and the wiring substrate  50 . 
     The piezoelectric element  42  has a shape nearly same as the shape of the pressure chamber  311  in a plan view, and is provided at the position facing the pressure chamber  311  across the vibration plate  32 . The piezoelectric element  42  is an actuator formed of a piezoelectric body (PZT in the embodiment) for deforming the vibration plate  32 . The two electrodes  421  and  422  are respectively provided on the upper and lower surfaces of the piezoelectric element  42 , and the electrode  422  on the lower surface side is fixed to the vibration plate  32 . 
     In the piezoelectric element spacer substrate  40 , the through hole  401  communicating with the through hole  321  of vibration palate  32  and running in the upward direction is formed independently from the space  41 . 
     The wiring substrate  50  includes an interposer  51  which is a substrate made of silicon. The lower surface of the interposer  51  is coated with two layers which are insulation layers  52  and  53  of silicon oxide. The upper surface is also coated with an insulation layer  54  of silicon oxide. The insulation layer  53  located lower among the insulation layers  52  and  53  is layered on the upper surface of the piezoelectric element spacer substrate  40 . 
     A through hole  511  running in the upward direction is formed in the interposer  51 , and a through electrode  55  is inserted in this through hole  511 . One end of the wiring  56  extending in the horizontal direction is connected to the lower end of the through electrode  55 . 
     The other end of this wiring  56  is connected above the electrode  421  of the upper surface of the piezoelectric element  42  via a connector  561 . The connector  561  is formed of a stud bump  561   a  provided on the lower surface of the wiring  56  and a conductive material  561   b  which is formed by being applied to the lower end side of the stud bump  561   a.    
     An individual wiring  57  is connected to the upper end of the through electrode  55 , and the individual wiring  57  extends in the horizontal direction and connected to a wiring member formed of FPC or the like. A drive signal is supplied to the piezoelectric element  42  via the wiring member and the individual wiring  57  from the drive circuit connected to the wiring member. 
     A through hole  512  communicating with the through hole  401  of the piezoelectric element spacer substrate  40  and running in the upward direction is formed in the interposer  51 . Among the insulation layers  52  to  54 , each portion coating the portion near the through hole  512  is formed to have an opening diameter larger than that of the through hole  512 . 
     The protective layer  60  is a layer protecting the individual wiring  57 , and layered on the upper surface of the insulation layer  54  of the interposer  51  while covering the individual wiring  57  provided on the upper surface of the wiring substrate  50 . In the protective layer  60 , an ink inflow port  601  communicating with the through hole  512  is formed. 
     Hereinafter, the piezoelectric element spacer substrate  40 , the wiring substrate  50  and the protective layer  60  will be also collectively referred to as an actuator unit. 
     In the head chip  10  in the present embodiment having such a configuration, the ink supplied from the ink inflow port  60  flows through the through holes  512  and  401  and pressure chambers  311  in order, to be pooled in the pressure chamber  311 . At the time of ink ejection, the ink flows through the large diameter portion  124 , the large diameter portion  113  and the nozzle  111  in order. A part of the ink flowing in the large diameter portion  113  is discharged outside through the individual ink discharge flow path  114  and the common ink discharge flow path  126 . 
     In the head chip  10  in the present embodiment, a first protective film not shown in the drawings is provided on the surface and the inner wall surface of the flowing path of ink for each of the nozzle substrate  11 , the flow path spacer substrate  12  and the vibration substrate  30 . The second protective film  72  is formed on the surface of the intermediate layered substrate which is formed of the flow path spacer substrate  12 , the vibration substrate  30 , the piezoelectric element spacer substrate  40 , the wiring substrate  50  and the protective layer  60 . As the first protective film and the second protective film  72 , the materials similar to those of the above embodiment can be used. 
       FIG. 16  is a flowchart for explaining the manufacturing process of inkjet head  100  in the second embodiment. 
     In the manufacturing process of inkjet head  100  in the present embodiment, the nozzle substrates  11  are first manufactured by splitting a composite nozzle substrate  11 M, which has the first protective film formed on its surface, into the nozzle substrates  11  by the process similar to that of the nozzle substrate manufacturing process in the first embodiment (step S 201  to S 203 ). In the present embodiment, in addition to the nozzle  111 , the large diameter portion  113  and the individual ink discharge flow path  114  are formed in the nozzle substrate  11 . 
     Next, the flow path spacer substrate  12  is manufactured by splitting the composite flow path spacer substrate  12 M, which has the first protective film formed on its surface, into the flow path spacer substrates  12  by the process similar to that of the flow path spacer substrate manufacturing process in the first embodiment (steps S 204  to S 206 : composite substrate manufacturing, first protective film forming, and splitting). In the present embodiment, the large diameter portion  124 , the diaphragm portion  125  and the common ink discharge flow path  126  are formed in the flow path spacer substrate  12 . 
     A composite vibration substrate having a plurality of regions which forms vibration substrates  30  by being split is then manufactured (step S 207 ). That is, in the silicon substrate, pressure chambers  311  corresponding to a plurality of vibration substrates  30  are formed, and the vibration plate  32  is attached to manufacture the composite vibration substrate. 
     The first protective film is formed on the surface of the composite vibration substrate and the inner wall surfaces of the pressure chambers  311  (step S 208 ). In this step, the film forming method which is same as that of step S 202  can be used. 
     The composite vibration substrate is split into a plurality of vibration substrates  30  by dividing the composite vibration substrate at predetermined dividing positions (step S 209 ). In this step, the same splitting method as that of step S 203  can be used. 
     In the vibration substrate  30  manufactured in step S 209 , the first protective film is not formed on the split faces. 
     The flow path spacer substrate  12  and the vibration substrate  30  are attached to each other via an adhesive, and the above-mentioned actuator unit (piezoelectric element spacer substrate  40 , wiring substrate  50  and protective layer  60 ) are further layered to manufacture the intermediate layered substrate (step S 210 ). 
     The second protective film  72  is formed on at least the surface of the intermediate layered substrate (step S 211 : second protective film forming). In this step, the same film forming method as that of step S 202  can be used. 
     Next, the nozzle substrate  11  is attached to the intermediate layered substrate via an adhesive to manufacture the head chip  10  (step S 212 : nozzle substrate fixing). The obtained head chip  10  and the exterior member  102  are bonded via the adhesive  80  (step S 213 : exterior member bonding), and the other components are incorporated into the housing  101  and the exterior member  102  to complete the inkjet head  100 . 
     Modification Example 
     A modification example of the second embodiment will be described. 
     In the above second embodiment, the second protective film  72  is formed on the surface of the intermediate layered substrate formed of the flow path spacer substrate  12 , the vibration substrate  30 , the piezoelectric element spacer substrate  40 , the wiring substrate  50  and the protective layer  60 . However, the second protective film  72  may be formed on the surface of a layered substrate in which the nozzle substrate  11  is further layered on the intermediate layered substrate. That is, the second protective film  72  may be formed on the surface of the nozzle substrate  11 . 
     When a water-repellent film is provided on the nozzle opening surface of the nozzle substrate  11  in the modification example, the water-repellent film may be formed to be superposed on the second protective film  72  provided on the nozzle opening surface of the nozzle substrate  11 . 
       FIG. 17  is a flowchart showing a manufacturing process of inkjet head  100  in the modification example. 
     The flowchart in  FIG. 17  is obtained by changing the steps S 210  and S 211  in the flowchart of  FIG. 16  to steps S 210   a  and S 211   a  and deleting step S 212 . Hereinafter, the difference from the flowchart in  FIG. 16  will be described. 
     In the manufacturing process of inkjet head  100  of the modification example, after the steps S 201  to S 209  end, the intermediate layered substrate is manufactured by attaching the nozzle substrate  11  and the flow path spacer substrate  12  and the vibration substrate  30  to each other via an adhesive, and further layering the actuator unit (step S 210   a : nozzle substrate fixing). The head chip  10  is obtained by forming the second protective film  72  on the obtained intermediate layered substrate (step S 211   a : second protective film forming), and thereafter, the exterior member  102  is bonded to the head chip  10  (step S 213 : exterior member bonding) to complete the inkjet head  100 . 
     In such a way, the present invention can also be applied to the inkjet head  100  of the bend mode. By the configurations of inkjet head  100  of the bend mode according to the second embodiment and the modification example, it is possible to more surely suppress the occurrence of trouble that the ink adhering to the surface of the flow path spacer substrate  12  enters and corrodes the ink flow path  121 . 
     The present invention is not limited to the above embodiments and modification examples, and various changes can be made. 
     For example, each of the above embodiments and modification examples has been described by taking the flow path spacer substrate  12  and the wiring substrate  14  as an example of “flow path substrate”. However, in addition to the flow path spacer substrate  12  and the wiring substrate  14 , the pressure chamber substrate  13  in the first embodiment and the actuator unit in the second embodiment may be a configuration corresponding to the “flow path substrate”. That is, after the first protective film  71  is formed on a composite substrate having a plurality of regions which forms pressure chamber substrates  13  by being split, the composite substrate may be split into the pressure chamber substrates  13  and the second protective film  72  may be formed on the split faces generated by the splitting. After the first protective film  71  is formed on a composite substrate having a plurality of regions which forms actuator units by being split, the composite substrate may be split into the actuator units and the second protective film  72  may be formed on the split faces generated by the splitting. In these cases, even when the pressure chamber substrate  13  or the actuator unit is manufactured by the splitting process of the composite substrate, it is possible to more surely suppress the trouble that the ink adhering from outside enters inside. 
     Each of the above embodiments and modification examples has been described by using an example in which each entire split face generated by splitting the composite substrate in each of the surfaces of the flow path spacer substrate  12 , the wiring substrate  14  and the like is exposed in the surface of the head chip  10 , and the protective film  72  is provided on the entire split face. However, the present invention is not limited to this. For example, in a configuration in which only a part of the split face generated by the splitting is exposed in the surface of the head chip  10 , it is sufficient that the second protective film  72  is provided on at least the exposed part of the split face. 
     Though each of the above embodiments and the modification examples has been described by using an example in which the head chip  10  and the exterior member  102  are bonded via the adhesive  80 , the present invention is not limited to this. For example, the head chip  10  may be fixed to the exterior member  102  directly or indirectly without an adhesive. 
     Though each of the above embodiments and the modification examples has been described by using an example in which the recording medium M is conveyed by the conveyance unit  2  including the conveyance belt  2   c , the present invention is not limited to this. The conveyance unit  2  may convey the recording the recording medium M by holding the recording medium M on the outer circumferential surface of a rotating conveyance drum, for example. 
     Each of the above embodiments and the modification examples has been described by taking, as an example, the single pass type inkjet recording device  1 . However, the present invention may also be applied to an inkjet recording device which records an image while causing the inkjet head  100  to perform scanning movement. 
     Though several embodiments of the present invention have been described above, the scope of the present invention is not limited to the above embodiments, and includes the scope of inventions, which is described in the scope of claims, and the scope equivalent thereof. 
     INDUSTRIAL APPLICABILITY 
     The present invention is applicable to an inkjet head manufacturing method, an inkjet recording device manufacturing method, an inkjet head, and an inkjet recording device. 
     EXPLANATION OF REFERENCE NUMERALS 
     
         
           1  inkjet recording device 
           2  conveyance unit 
           3  head unit 
           10  head chip 
           11  nozzle substrate 
           11   a  exposed face (split face) 
           111  nozzle 
           112  nozzle opening surface 
           11 M composite nozzle substrate 
           12  flow path spacer substrate 
           12   a  exposed face (split face) 
           121  ink flow path 
           122  through flow path 
           123  individual ink discharge flow path 
           123   a  horizontal individual discharge flow path 
           123   b  vertical individual discharge flow path 
           12 M composite flow path spacer substrate 
           13  pressure chamber substrate 
           131  pressure chamber 
           132  common ink discharge flow path 
           132   a  horizontal common discharge flow path 
           132   b  vertical common discharge flow path 
           133  drive electrode 
           134  dividing wall 
           135  connection electrode 
           14  wiring substrate 
           14   a  exposed face (split face) 
           141  ink supply port 
           142  discharge hole 
           143  wiring 
           20  FPC 
           30  vibration substrate 
           71 ,  71   a ,  71   b ,  71   c  first protective film 
           72  second protective film 
           80  adhesive 
           100  inkjet head 
           101  housing 
           102  exterior member 
           1021  top board 
           1021   a  recess formed surface 
           1021   b  exposing through hole 
           1022  lateral wall 
           1023  sealing plate 
         M recording medium 
         R recess