Patent Publication Number: US-11654683-B2

Title: Head chip, liquid jet head, liquid jet recording device, and method of manufacturing head chip

Description:
RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2021-116504, filed on Jul. 14, 2021, and Japanese Patent Application No. 2020-193668, filed on Nov. 20, 2020, the entire content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to a head chip, a liquid jet head, a liquid jet recording device, and a method of manufacturing a head chip. 
     2. Description of the Related Art 
     An inkjet head to be installed in an inkjet printer ejects ink to a recording target medium through a head chip installed in the inkjet head. The head chip is provided with an actuator plate in which ejection channels and non-ejection channels formed alternately, and a nozzle plate bonded to the actuator plate. In the actuator plate, electrodes are formed respectively on inner surfaces of the ejection channels and the non-ejection channels. 
     In the head chip, by the volume of an inside of the ejection channel changing due to a voltage applied to the electrode, the ink in the ejection channel is ejected through a nozzle hole provided to the nozzle plate. 
     For example, in JP-A-2012-131175 and JP-A-2017-136724, there is disclosed a configuration in which a protective film which covers the electrode and has an insulation property is formed on the inner surface of the ejection channel. According to this configuration, it is conceivable that it is possible to prevent the electrodes from shorting via the ink inside the ejection channel even when using conductive ink. 
     Incidentally, in the head chip, there is a possibility that the conductive ink inflows into the non-ejection channel from the inside of the ejection channel through a void in the actuator plate, a joint portion between the actuator plate and other members, and so on. 
     However, in the related-art configuration, room for improvement still exists in the point that the protective film is actively formed on the inner surface of the non-ejection channel. When the ink supposedly inflows into the non-ejection channel, there is a possibility that the electrodes formed on the inner surface of the non-ejection channel short via the ink. 
     SUMMARY OF THE INVENTION 
     The present disclosure provides a head chip, a liquid jet head, a liquid jet recording device, and a method of manufacturing the head chip each capable of preventing the short circuit of electrodes by ink to maintain an excellent ejection performance over a long period of time. 
     In view of the problem described above, the present disclosure adopts the following aspects. 
     (1) The head chip according to an aspect of the present disclosure includes an actuator plate having a first channel area and a second channel area disposed side by side in a first direction, a first jet channel extending in the first direction and a first non-jet channel extending in the first direction being arranged in a second direction crossing the first direction in the first channel area, and a second jet channel extending in the first direction and a second non-jet channel extending in the first direction being arranged in the second direction in the second channel area, a cover plate which has a first liquid flow channel communicated with the first jet channel, and a second liquid flow channel communicated with the second jet channel, and which is stacked on the actuator plate, and a communication plate which has a first communication hole communicated with the first jet channel in a central portion in the first direction, and a second communication hole communicated with the second jet channel in a central portion in the first direction, and which is stacked on the actuator plate at an opposite side to the cover plate, wherein protective films are formed respectively on an inner surface of the first jet channel, an inner surface of the first non-jet channel, an inner surface of the second jet channel, and an inner surface of the second non-jet channel, in the actuator plate, first open apertures which communicate an inside and an outside of the first non-jet channel with each other are formed in both end portions of the first non-jet channel in the first direction, and in the actuator plate, second open apertures which communicate an inside and an outside of the second non-jet channel with each other are formed in both end portions of the second non-jet channel in the first direction. 
     According to the present aspect, by introducing the formation material of the protective film into the first non-jet channel through the first open apertures formed in the both end portions of the first non-jet channel, it is possible to effectively form the protective film on the inner surface of the first non-jet channel. By introducing the formation material of the protective film into the second non-jet channel through the second open apertures formed in the both end portions of the second non-jet channel, it is possible to effectively form the protective film on the inner surface of the second non-jet channel. 
     As a result, it is possible to prevent the short circuit or the like of the electrodes formed on the inner surfaces of the non-jet channels caused by, for example, liquid having entered the non-jet channels. 
     (2) In the head chip according to (1) described above, it is preferable that the first open apertures include a first inside open aperture located in the end portion of the first non-jet channel at the second channel area side in the first direction, and a first outside open aperture located in the end portion of the first non-jet channel at an opposite side to the second channel area side in the first direction, the second open apertures include a second inside open aperture located in the end portion of the second non-jet channel at the first channel area side in the first direction, and a second outside open aperture located in the end portion of the second non-jet channel at an opposite side to the first channel area side in the first direction, and a common groove which extends in the second direction, and which is communicated with the first inside open apertures in a plurality of the first non-jet channels, and the second inside open apertures of a plurality of the second non-jet channels is formed in a boundary portion located between the first channel area and the second channel area in the first direction in the actuator plate and the communication plate. 
     According to the present aspect, the formation material of the protective film is introduced into the non-jet channels via the inside open apertures from the common groove. Thus, it is possible to efficiently form the protective films compared to when introducing the formation material of the protective films individually into the non-jet channels through the inside open apertures. 
     (3) In the head chip according to (2) described above, it is preferable that the cover plate is provided with a communication groove communicated with the common groove. 
     According to the present aspect, since it is possible to reduce the pressure loss in the space connected to the open apertures, it is possible to efficiently introduce the formation material of the protective film into the non-jet channels through the inside open apertures. 
     (4) In the head chip according to (3) described above, it is preferable that the communication groove is made larger in width in the first direction than the common groove, and the communication groove is communicated with the first inside open aperture and the second inside open aperture from an opposite side to the communication plate with respect to the actuator plate. 
     According to the present aspect, the formation material of the protective film having entered the communication groove through the common groove is introduced into the non-jet channels through the inside open apertures from the opposite side to the communication plate with respect to the actuator plate. Thus, the formation material of the protective films is introduced into the non-ejection channels directly through the common groove or indirectly through the communication groove. As a result, it is possible to efficiently form the protective films on the inner surfaces of the non-jet channels. 
     (5) In the head chip according to (3) or (4) described above, it is preferable that the cover plate includes a first common flow channel communicated with a plurality of the first liquid flow channels in a lump, and a second common flow channel communicated with a plurality of the second liquid flow channels in a lump, and a portion located between the first liquid flow channel and the second common flow channel in the cover plate constitutes a beam part which partitions the first common flow channel and the second common flow channel from each other, and which extends in the second direction. 
     According to the present aspect, it becomes easy to ensure the strength of the cover plate with the beam parts. Therefore, when bonding the actuator plate and the cover plate to each other, the bonding load can effectively be applied between the actuator plate and the cover plate. As a result, it is possible to surely bond the actuator plate and the cover plate to each other to prevent the leakage of the ink through an area between the actuator plate and the cover plate. 
     (6) In the head chip according to (5) described above, it is preferable that the communication groove is provided to the beam part, and a width in the first direction of the communication groove is narrower than a width of the beam part in the first direction. 
     According to the present aspect, by providing the beam part with the communication groove, it becomes easy to ensure the depth of the communication groove. Therefore, it is possible to efficiently introduce the raw material gas of the protective film into the non-jet channels through the open apertures. 
     Moreover, since the width in the first direction of the communication groove is narrower than the width in the first direction of the beam part, a portion located at the outer side of the communication groove out of the beam part forms a pressure receiving area. The pressure receiving area functions as a pressure receiving surface for receiving the load which acts between the actuator plate and the cover plate when bonding the actuator plate and the cover plate to each other. Thus, it is possible to effectively apply the bonding load between the actuator plate and the cover plate. As a result, it is possible to prevent the leakage of the ink or the like through the area between the actuator plate and the cover plate. 
     (7) In the head chip according to (6) described above, it is preferable that the communication groove overlaps the first common flow channel and the second common flow channel in a stacking direction in which the actuator plate and the cover plate are stacked on one another. 
     According to the present aspect, it becomes easy to ensure the depth of the communication groove, and therefore, it is possible to efficiently introduce the raw material gas of the protective film into the non-jet channels through the open apertures. 
     (8) In the head chip according to any of (2) to (7) described above, it is preferable that the first non-jet channel includes a first extension part extending in the first direction, and a first uprise part having a groove depth gradually decreasing in a direction from the first extension part toward the second channel area in the first direction, the second non-jet channel includes a second extension part extending in the first direction, and a second uprise part having a groove depth gradually decreasing in a direction from the second extension part toward the first channel area in the first direction, the first uprise part traverses the common groove in the first direction, and has a communication portion with the common groove constituting the first inside open aperture, and the second uprise part traverses the common groove in the first direction, and has a communication portion with the common groove constituting the second inside open aperture. 
     According to the present aspect, it is easy to ensure the aperture area of the inside open aperture compared to when the common groove is communicated in an end portion of the uprise part. Thus, it is possible to efficiently introduce the formation material of the protective film into the non-jet channels through the inside open apertures. 
     (9) The liquid jet head according to the present aspect includes the head chip according to any of the aspects (1) to (8) described above. 
     According to the present aspect, since the head chip according to any of the aspects described above is provided, it is possible to prevent the short circuit or the like of the electrodes caused by the liquid, and thus, it is possible to maintain the excellent jet performance over a long period of time. 
     (10) The liquid jet recording device according to the present aspect includes the liquid jet head according to the aspect (9) described above. 
     According to the present aspect, since the liquid jet head according to the aspect described above is provided, it is possible to prevent the short circuit or the like of the electrodes caused by the liquid, and thus, it is possible to maintain the excellent jet performance over a long period of time. 
     (11) The method of manufacturing a head chip according to an aspect of the present disclosure is a method of manufacturing the head chip of introducing the formation material of the protective film into the non-jet channels through the open apertures, the head chip including an actuator plate in which a jet channel extending in a first direction and a non-jet channel extending in the first direction are arranged in a second direction crossing the first direction, a cover plate which includes a liquid flow channel communicated with the jet channel, and which is stacked on the actuator plate, and a communication plate which has a communication hole communicated with the jet channel in a central portion in the first direction, and which is stacked on the actuator plate at an opposite side to the cover plate, in the actuator plate, open apertures which communicate an inside and an outside of the non-jet channel with each other being formed in both end portions of the non-jet channel in the first direction, and the method including a protective film formation step of forming protective films on an inner surface of the jet channel and an inner surface of the non-jet channel, wherein in the protective film formation step, a formation material of the protective films is introduced into the jet channel through the liquid flow channel and the communication hole, and the formation material of the protective films is introduced into the non-jet channel through the open apertures. 
     According to the present aspect, by introducing the formation material of the protective film into the jet channel through the liquid flow channel and the communication hole, and introducing the formation material of the protective film into the non-jet channel through the open apertures, it is possible to effectively form the protective film on the inner surface of the jet channel and the inner surface of the non-jet channel. 
     As a result, it is possible to prevent the short circuit or the like of the electrodes formed on the inner surfaces of the jet channels and the non-jet channels caused by, for example, the liquid having entered the jet channels and the non-jet channels. 
     According to an aspect of the present disclosure, it is possible to prevent the short circuit of the electrodes caused by the liquid, and thus, it is possible to maintain the excellent jet performance over a long period of time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic configuration diagram of an inkjet printer according to a first embodiment. 
         FIG.  2    is a schematic configuration diagram of an inkjet head and an ink circulation mechanism according to the first embodiment. 
         FIG.  3    is a perspective view of a head chip according to the first embodiment in a state in which a nozzle plate is detached viewed from a −Z side. 
         FIG.  4    is an exploded perspective view of the head chip according to the first embodiment. 
         FIG.  5    is a bottom view of an actuator plate according to the first embodiment. 
         FIG.  6    is a cross-sectional view corresponding to the line VI-VI shown in  FIG.  5   . 
         FIG.  7    is a cross-sectional view corresponding to the line VII-VII shown in  FIG.  5   . 
         FIG.  8    is an enlarged view of a VIII portion shown in  FIG.  7   . 
         FIG.  9    is a cross-sectional view along the line IX-IX shown in  FIG.  4   . 
         FIG.  10    is an enlarged cross-sectional view of a plate assembly according to the first embodiment. 
         FIG.  11    is an enlarged cross-sectional view of a head chip according to a second embodiment. 
         FIG.  12    is an enlarged cross-sectional view of a head chip according to another configuration of the second embodiment. 
         FIG.  13    is an enlarged cross-sectional view of a head chip according to a modified example. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Some embodiments according to the present disclosure will hereinafter be described with reference to the drawings. In the embodiments and a modified example described hereinafter, corresponding configurations are denoted by the same reference symbols and the description thereof will be omitted in some cases. It should be noted that in the following description, expressions representing relative or absolute arrangement such as “parallel,” “perpendicular,” “center,” and “coaxial” not only represent strictly such an arrangement, but also represent the state of being relatively displaced with a tolerance, or an angle or a distance to the extent that the same function can be obtained. In the following embodiments, the description will be presented citing an inkjet printer (hereinafter simply referred to as a printer) for performing recording on a recording target medium using ink (liquid) as an example. It should be noted that the scale size of each member is arbitrarily modified so as to provide a recognizable size to the member in the drawings used in the following description. 
     First Embodiment 
     [Printer  1 ] 
       FIG.  1    is a schematic configuration diagram of the printer  1 . 
     As shown in  FIG.  1   , the printer (a liquid jet recording device)  1  according to the present embodiment is provided with a pair of conveying mechanisms  2 ,  3 , ink tanks  4 , inkjet heads (liquid jet heads)  5 , an ink circulation mechanism  6 , and a scanning mechanism  7 . 
     In the following explanation, the description is presented using an orthogonal coordinate system of X, Y, and Z as needed. In this case, the X direction (a second direction) coincides with a conveying direction (a sub-scanning direction) of a recording target medium P (e.g., paper). The Y direction (a first direction) coincides with a scanning direction (a main scanning direction) of the scanning mechanism  7 . The Z direction is a height direction (a gravitational direction) perpendicular to the X direction and the Y direction. In the following explanation, the description will be presented defining an arrow side as a positive (+) side, and an opposite side to the arrow as a negative (−) side in the drawings in each of the X direction, the Y direction, and the Z direction. In the present embodiment, the +Z side corresponds to an upward direction in the gravitational direction, and the −Z side corresponds to a downward direction in the gravitational direction. 
     The conveying mechanisms  2 ,  3  convey the recording target medium P toward the +X side. The conveying mechanisms  2 ,  3  each include a pair of rollers  11 ,  12  extending in, for example, the Y direction. 
     The ink tanks  4  respectively house ink of four colors such as yellow, magenta, cyan, and black. The inkjet heads  5  are configured so as to be able to respectively eject the ink of four colors, namely yellow, magenta, cyan, and black in accordance with the ink tank  4  coupled thereto. It should be noted that the ink to be housed in the ink tanks  4  can be conductive ink, or can also be nonconductive ink. 
       FIG.  2    is a schematic configuration diagram of the inkjet head  5  and the ink circulation mechanism  6 . 
     As shown in  FIG.  1    and  FIG.  2   , the ink circulation mechanism  6  circulates the ink between the ink tank  4  and the inkjet head  5 . Specifically, the ink circulation mechanism  6  is provided with a circulation flow channel  23  having an ink supply tube  21  and an ink discharge tube  22 , a pressure pump  24  coupled to the ink supply tube  21 , and a suction pump  25  coupled to the ink discharge tube  22 . 
     The pressure pump  24  pressurizes the inside of the ink supply tube  21  to deliver the ink to the inkjet head  5  through the ink supply tube  21 . Thus, the ink supply tube  21  is provided with positive pressure with respect to the ink jet head  5 . 
     The suction pump  25  is depressurizes the inside of the ink discharge tube  22  to suction the ink from the inkjet head  5  through the ink discharge tube  22 . Thus, the ink discharge tube  22  is provided with negative pressure with respect to the ink jet head  5 . It is arranged that the ink can circulate between the inkjet head  5  and the ink tank  4  through the circulation flow channel  23  by driving the pressure pump  24  and the suction pump  25 . 
     The scanning mechanism  7  reciprocates the inkjet heads  5  in the Y direction. The scanning mechanism  7  is provided with a guide rail  28  extending in the Y direction, and a carriage  29  movably supported by the guide rail  28 . 
     &lt;Inkjet Head  5 &gt; 
     As shown in  FIG.  1   , the inkjet head  5  is mounted on the carriage  29 . In the illustrated example, the plurality of inkjet heads  5  is mounted on the single carriage  29  so as to be arranged side by side in the Y direction. The inkjet heads  5  are each provided with a head chip  50  (see  FIG.  3   ), an ink supply section (not shown) for coupling the ink circulation mechanism  6  and the head chip  50 , and a control section (not shown) for applying a drive voltage to the head chip  50 . 
     &lt;Head Chip  50 &gt; 
       FIG.  3    is a perspective view of the head chip  50  in the state in which a nozzle plate  51  is detached viewed from a −Z side.  FIG.  4    is an exploded perspective view of the head chip  50 . 
     The head chip  50  shown in  FIG.  3    and  FIG.  4    is a so-called circulating side-shooting type head chip which circulates the ink with the ink tank  4 , and at the same time, ejects the ink from a central portion in an extending direction (the Y direction) in an ejection channel  75  described later. The head chip  50  is provided with the nozzle plate  51  (see  FIG.  4   ), an intermediate plate (a communication plate)  52 , an actuator plate  53 , and a cover plate  54 . The head chip  50  is provided with a configuration in which the nozzle plate  51 , the intermediate plate  53 , the actuator plate  53 , and the cover plate  54  are stacked on one another in this order in the Z direction. In the following description, the description is presented in some cases defining a direction (+Z side) from the nozzle plate  51  toward the cover plate  54  as a reverse side, and a direction (−Z side) from the cover plate  54  toward the nozzle plate  51  along the Z direction as an obverse side. 
     The actuator plate  53  is formed of a piezoelectric material such as PZT (lead zirconate titanate). The actuator plate  53  is a so-called chevron substrate formed by, for example, stacking two piezoelectric plates different in polarization direction in the Z direction on one another. It should be noted that the actuator plate  53  can be a so-called monopole substrate in which the polarization direction is unidirectional throughout the entire area in the Z direction. 
       FIG.  5    is a bottom view of the actuator plate  53 . 
     As shown in  FIG.  4    and  FIG.  5   , the actuator plate  53  is provided with a plurality of (e.g., 4 columns of) channel columns  61  through  64 . The channel columns  61  through  64  extend in the X direction, and at the same time, are arranged at intervals in the Y direction. In the present embodiment, the channel columns  61  through  64  consist of a first channel A column (a first channel area)  61 , a first channel B column (a second channel area)  62 , a second channel A column (the first channel area)  63 , and a second channel B column (the second channel area)  64 . The first channel A column  61  and the first channel B column  62  constitute a first channel group  66 . The second channel A column  63  and the second channel B column  64  constitute a second channel group  67 . 
     As shown in  FIG.  5   , in the actuator plate  53 , a portion located between the channel groups  66 ,  67  is provided with a group separation groove  71 . The group separation groove  71  penetrates the actuator plate  53  in the Z direction, and at the same time, extends in the X direction. The group separation groove  71  separates the channel groups  66 ,  67  from each other. It should be noted that the head chip  50  forms substantially the same configurations at both sides in the Y direction with respect to the group separation groove  71 . Therefore, in the following description, the configuration at the −Y side with respect to the group separation groove  71  will mainly be described, and the description of the configuration at the +Y side will arbitrarily be omitted. 
     In the actuator plate  53 , a portion located between the first channel A column  61  and the first channel B column  62 , and a portion located between the second channel A column  63  and the second channel B column  64  are each provided with a column separation groove  72 . The column separation groove  72  penetrates the actuator plate  53  in the Z direction, and at the same time, extends in the X direction. The column separation groove  72  is made narrower in width in the Y direction than the group separation groove  71 . It should be noted that the separation grooves  71 ,  72  do not penetrate the actuator plate  53  in the X direction. 
     The configuration of the channel columns  61  through  64  will be hereinafter described citing the first channel A column  61  as an example. In the following description, constituents related to the column A in each of the channel columns  61  through  64  are denoted by reference symbols suffixed with A, constituents related to the column B are denoted by reference symbols suffixed with B, and the description of the configurations which are the same or corresponding between the column A and the column B will be omitted in some cases. Further, in each of the channel columns  61  through  64 , when there is no need to distinguish the column A and the column B from each other, the suffix A or B will be omitted. 
     The first channel A column  61  is formed at an opposite side (the −Y side) to the group separation groove  71  with respect to the column separation groove  72  in the actuator plate  53 . The first channel A column  61  has ejection channels (first jet channels)  75 A filled with the ink, and non-ejection channels (first non-jet channels)  76 A not filled with the ink. The channels  75 A,  76 A each extend linearly in the Y direction, and at the same time, are arranged side by side at intervals in the X direction in the plan view viewed from the Z direction. In the actuator plate  53 , a portion located between the ejection channel  75 A and the non-ejection channel  76 A constitutes a drive wall  70  (see  FIG.  4   ) which partitions the ejection channel  75 A and the non-ejection channel  76 A from each other in the X direction. It should be noted that the configuration in which the channel extension direction coincides with the Y direction will be described in the present embodiment, but the channel extension direction can cross the Y direction. 
       FIG.  6    is a cross-sectional view corresponding to the line VI-VI shown in  FIG.  5   . 
     As shown in  FIG.  6   , the ejection channel  75 A is formed to have a curved shape convex toward the obverse surface in a side view viewed from the X direction. The ejection channels  75  are formed by, for example, making a dicer having a disk-like shape enter the actuator plate  53  from the reverse surface (the +Z side) thereof. Specifically, the ejection channel  75 A has uprise parts  75   a  located at both end portions in the Y direction, and a penetration part  75   b  located between the uprise parts  75   a.    
     The uprise part  75   a  has a circular arc shape which extends along, for example, the curvature radius of the dicer and has a uniform curvature radius when viewed from the X direction. The uprise part  75   a  extends while curving toward the reverse side as getting away from the penetration part  75   b  in the Y direction. 
     The penetration part  75   b  penetrates the actuator plate  53  in the Z direction. 
       FIG.  7    is a cross-sectional view corresponding to the line VII-VII shown in  FIG.  5   . 
     As shown in  FIG.  7   , the non-ejection channel  76 A is adjacent to the ejection channel  75 A across the drive wall  70  in the X direction. The non-ejection channel  76 A is formed by, for example, making a dicer having a disk-like shape enter the actuator plate  53  from the reverse surface (the +Z side) thereof. The non-ejection channel  76 A is provided with a penetration part (a first extension part)  76   a , and an uprise part (a first uprise part)  76   b.    
     The penetration part  76   a  penetrates the actuator plate  53  in the Z direction. In other words, the penetration part  76   a  is formed to have a uniform groove depth in the Z direction. The penetration part  76   a  constitutes a portion other than the +Y side end portion in the non-ejection channel  76 . 
     The uprise part  76   b  constitutes the +Y side end portion in the non-ejection channel  76 . The uprise part  76   b  has a circular arc shape which extends along, for example, the curvature radius of the dicer and has a uniform curvature radius when viewed from the X direction. The uprise part  76   b  extends while curving toward the reverse side as getting away from the penetration part  76   a  in the Y direction. 
     As shown in  FIG.  6    and  FIG.  7   , the dimension in the Y direction of the non-ejection channel  76 A is made longer than that of the ejection channel  75 A. Specifically, in the non-ejection channel  76 A, the −Y side end portion of the penetration part  76   a  is located at the −Y side of the ejection channel  75 A, and the +Y side end portion of the uprise part  76   b  is located at the +Y side of the ejection channel  75 A. 
     As shown in  FIG.  5   , the first channel B column  62  is disposed between the group separation groove  71  and the column separation groove  72  in the actuator plate  53 . Similarly to the first channel A column  61  described above, the first channel B column  62  has a configuration in which ejection channels (second ejection channels)  75 B and non-ejection channels (second non-ejection channels)  76 B are arranged side by side in the X direction. Specifically, the ejection channel  75 B and the non-ejection channel  76 B are arranged so as to be shifted as much as a half pitch from the arrangement pitch of the ejection channel  75 A and the non-ejection channel  76 A. Therefore, in the inkjet head  5  according to the present embodiment, the ejection channels  75  of the first channel A column  61  and the first channel B column  62  are arranged in a zigzag manner (a staggered manner), and the non-ejection channels  76  of the first channel A column  61  and the first channel B column  62  are arranged in a zigzag manner (a staggered manner). In other words, the ejection channel  75  and the non-ejection channel  76  are opposed to each other in the Y direction between the channel columns  61 ,  62  adjacent to each other. It should be noted that the ejection channels  75  can be opposed to each other in the Y direction between the channel columns  61 ,  62 , and the non-ejection channels  76  can be opposed to each other in the Y direction between the channel columns  61 ,  62 . It should be noted that it is possible for the channel columns  61  through  64  to be disposed so as to be shifted by a quarter pitch with respect to the arrangement pitch of the ejection channels  75 A and the non-ejection channels  76 A in the first channel A column  61 . 
     In the channel columns  61 ,  62 , the ejection channels  75  are formed plane-symmetrically about the X-Z plane passing through the center in the Y direction of the column separation groove  72 . 
     In the channel columns  61 ,  62 , the non-ejection channels  76  are formed plane-symmetrically about the X-Z plane passing through the center in the Y direction of the column separation groove  72 . 
     In the actuator plate  53 , a portion located at the −Y side of the ejection channel  75 A (the penetration part  75   b ) of the first channel A column  61  constitutes a first outside area  81 . In the actuator plate  53 , a portion located between a portion located at the +Y side of the ejection channel  75 A of the first channel A column  61 , and the column separation groove  72  constitutes a first inside area  82 . 
     In the actuator plate  53 , a portion located between a portion located at the −Y side of the ejection channel  75 B of the first channel B column  62 , and the column separation groove  72  constitutes a second inside area  85 . In the actuator plate  53 , a portion located between a portion located at the +Y side of the ejection channel  75 B of the first channel B column  62 , and the column separation groove  71  constitutes a second outside area  86 . 
     As shown in  FIG.  7   , in the first channel A column  61 , the penetration part  76   a  of the non-ejection channel  76 A penetrates the first outside area  81  in the Y direction and the Z direction. In the penetration part  76   a , an opening part on an outer surface of the first outside area  81  constitutes an open aperture (a first outside open aperture)  53   a  for communicating the inside and the outside of the non-ejection channel  76 A. 
       FIG.  8    is an enlarged view of a VIII portion shown in  FIG.  7   . 
     As shown in  FIG.  8   , in the first channel A column  61 , the uprise part  76   b  of the non-ejection channel  76 A traverses the column separation groove  72  in the Y direction. Therefore, a part (the +Y side end portion) of the uprise part  76   b  reaches the second inside area  85  of the first channel B column  62 . Specifically, a portion located in the first inside area  82  in the uprise part  76   b  of the non-ejection channel  76 A constitutes a communication part  90 A for communicating the penetration part  76   a  and the column separation groove  72  with each other. The communication part  90 A opens in the column separation groove  72  through an open aperture (a first inside open aperture)  90   a A. A portion which reaches the second inside area  85  in the uprise part  76   b  of the non-ejection channel  76 A constitutes a divided part  91 A divided by the column separation groove  72 . 
     As shown in  FIG.  6   , in the first channel B column  62 , the penetration part  76   a  of the non-ejection channel  76 B penetrates the second outside area  86  in the Y direction and the Z direction. In the penetration part  76   a , an opening part on an outer surface of the second outside area  86  constitutes an open aperture (a second outside open aperture)  53   b  for communicating the inside and the outside of the non-ejection channel  76 B. 
     As shown in  FIG.  8   , in the first channel B column  62 , the uprise part (a second uprise part)  76   b  of the non-ejection channel  76 B traverses the column separation groove  72  in the Y direction. Therefore, a part (the −Y side end portion) of the uprise part  76   b  reaches the first inside area  82  of the first channel A column  61 . Specifically, a portion located in the second inside area  85  in the uprise part  76   b  constituting the first channel B column  62  constitutes a communication part  90 B for communicating the penetration part (a second extension part)  76   a  and the column separation groove  72  with each other. The communication part  90 B opens in the column separation groove  72  through an open aperture  90   a B. A portion which reaches the first inside area  82  in the uprise part  76   b  of the non-ejection channel  76 B constitutes a divided part  91 B divided by the column separation groove  72 . It should be noted that the uprise part  76   b  is not required to traverse the column separation groove  72  as long as the uprise part  76   b  is provided with a configuration of being communicated with at least the column separation groove  72 . In other words, it is possible for the uprise part  76   b  to have a configuration not provided with the divided parts  91 . 
       FIG.  9    is a cross-sectional view along the line IX-IX shown in  FIG.  4   . 
     As shown in  FIG.  9   , on inside surfaces (surfaces opposed to each other in the X direction in the inner surfaces of the ejection channel  75 ) of each of the ejection channels  75  in the drive walls  70  of the actuator plate  53 , there are respectively formed common electrodes  95 . The common electrodes  95  are each formed throughout the entire area in the Z direction on the inside surface of the ejection channel  75 . The common electrodes  95  are made equivalent in length in the Y direction to the penetration part  75   b  of the ejection channel  75  (the length in the Y direction of the common electrodes  95  is made equivalent to an opening length of the ejection channel  75  on the obverse surface of the actuator plate  53 ). 
     As shown in  FIG.  5   , on the obverse surface of the actuator plate  53 , there is formed a plurality common terminals  96 . The common terminals  96  are made to have strip-like shapes extending in the Y direction in parallel to each other. The common terminals  96  are each coupled to a pair of the common electrodes  95  at an opening edge of the ejection channel  75  corresponding to the common terminal  96 . The common terminals  96  are each terminated in corresponding one of the outside areas  81 ,  86 . 
     As shown in  FIG.  9   , on inside surfaces (surfaces opposed to each other in the X direction in the non-ejection channel  76 ) of each of the non-ejection channels  76  in the drive walls  70  of the actuator plate  53 , there are respectively formed individual electrodes  97 . The individual electrodes  97  are each formed throughout the entire area in the Z direction on the inside surface of the non-ejection channel  76 . 
     As shown in  FIG.  5   , in a portion located at an outer side in the Y direction of the common terminal  96  on the obverse surface of each of the outside areas  81 ,  86 , there is formed an individual terminal  98 . The individual terminal  98  is made shaped like a strip extending in the X direction. The individual terminal  98  couples the individual electrodes  97  opposed to each other in the X direction across the ejection channel  75  at the opening edges of the non-ejection channels  76  opposed to each other in the X direction across the ejection channel  75 . It should be noted that in a portion located between the common terminal  96  and the individual terminal  98  in each of the outside areas  81 ,  86 , there is formed a compartment groove  99 . The compartment groove  99  extends in the X direction in each of the outside areas  81 ,  86 . The compartment groove  99  separates the common terminal  96  and the individual terminal  98  from each other. It should be noted that in  FIG.  3   ,  FIG.  4   , and so on, the electrodes  95 ,  97  and the terminals  96 ,  98  are only partially shown. 
     As shown in  FIG.  6   , to the obverse surface of the first outside area  81 , there is pressure-bonded a first flexible printed board  100 . The first flexible printed board  100  is coupled to the common terminals  96  and the individual terminals  98  corresponding to the first channel A column  61  on the obverse surface of the first outside area  81 . The first flexible printed board  100  is extracted toward the +Z side through the outside of the actuator plate  53 . 
     To the obverse surface of the second outside area  86 , there is pressure-bonded a second flexible printed board  101 . The second flexible printed board  101  is coupled to the common terminals  96  and the individual terminals  98  corresponding to the first channel B column  62  on the obverse surface of the second outside area  86 . The second flexible printed board  101  is extracted toward the +Z side through the inside of the group separation groove  71 . 
     As shown in  FIG.  9   , on the inner surface of the ejection channel  75 , there is formed a first protective film  110 . The first protective film  110  is formed throughout the entire inner surface of the ejection channel  75 . The first protective film  110  covers the common electrode  95 . The first protective film  110  prevents, for example, the common electrode  95  and the ink from making contact with each other. It should be noted that it is sufficient for the first protective film  110  to cover at least the common electrode  95  on the inside surface of the ejection channel  75 . 
     On an inner surface of the non-ejection channel  76 , there is formed a second protective film  111 . The second protective film  111  is formed throughout the entire inner surface of the non-ejection channel  76 . The second protective film  111  covers the individual electrode  97 . The second protective film  111  prevents, for example, the individual electrode  97  and the ink from making contact with each other. It should be noted that it is sufficient for the second protective film  111  to cover at least the individual electrode  97  on the inside surface of the non-ejection channel  76 . 
     The protective films  110 ,  111  each include an organic insulating material such as a para-xylylene resin material (e.g., parylene (a registered trademark)). The protective films  110 ,  111  can be formed of tantalum oxide (Ta2O5), silicon nitride (SiN), silicon carbide (SiC), silicon oxide (SiO2), diamond-like carbon, or the like, or can include at least any one of these materials. 
     &lt;Cover Plate  54 &gt; 
     As shown in  FIG.  3    and  FIG.  4   , the cover plate  54  is bonded to the reverse surface of the actuator plate  53  so as to close the channel groups  66 ,  67 . In the cover plate  54 , at positions corresponding to the channel columns  61  through  64 , there are formed entrance common ink chambers  120  and exit common ink chambers  121 . 
     The entrance common ink chamber  120  is formed at a position overlapping the +Y side end portion of the ejection channel  75 A in the plan view in, for example, the first channel A column  61 . The entrance common ink chamber  120  extends in the X direction with a length sufficient for straddling, for example, the first channel A column  61 , and at the same time, opens on the reverse surface of the cover plate  54 . 
     The exit common ink chamber  121  is formed at a position overlapping the −Y side end portion of the ejection channel  75 A in the plan view in, for example, the first channel A column  61 . The exit common ink chamber  121  extends in the X direction with a length sufficient for straddling the first channel A column  61 , and at the same time, opens on the reverse surface of the cover plate  54 . 
     In the entrance common ink chamber  120 , at the position corresponding to the ejection channels  75 A in the first channel A column  61 , there is formed an entrance slit (a first liquid flow channel, a second liquid flow channel)  125 . The entrance slit  125  communicates the +Y side end portion of each of the ejection channels  75 A and the entrance common ink chamber  120  with each other. 
     In the exit common ink chamber  121 , at the position corresponding to the ejection channels  75 A in the first channel A column  61 , there is formed an exit slit (the first liquid flow channel, the second liquid flow channel)  126 . The exit slit  126  communicates the −Y side end portion of each of the ejection channels  75 A and the exit common ink chamber  121  with each other. Therefore, the entrance slit  125  and the exit slit  126  are communicated with the ejection channels  75 A on the one hand, but are not communicated with the non-ejection channel  76 A on the other hand. 
     In the cover plate  54 , an area between the entrance common ink chambers (a first common flow channel, a second common flow channel)  120  adjacent to each other forms a beam part  128 . The beam part  128  extends linearly along the X direction. The beam part  128  partitions the entrance common ink chambers  120  adjacent to each other. 
     As shown in  FIG.  8   , on the obverse surface of the cover plate  54  (the beam part  128 ), at a position overlapping the column separation groove  72  in the plan view, there is formed a communication groove  127 . The communication groove  127  opens on the obverse surface of the cover plate  54 , and is communicated with the column separation groove  72 . The communication groove  127  extends in the X direction with the length sufficient for traversing the channel columns  61  through  64 . The dimension in the Y direction of the communication groove  127  is made longer than the column separation groove  72 . Therefore, the communication groove  127  is communicated with the communication part  90  of the non-ejection channel  76  on the reverse surface of the actuator plate  53 . 
     &lt;Intermediate Plate  52 &gt; 
     The intermediate plate  52  is bonded to the obverse surface of the actuator plate  53  so as to close the channel groups  66 ,  67 . The intermediate plate  52  is formed of a piezoelectric material such as PZT similarly to the actuator plate  53 . The intermediate plate  52  is thinner in thickness in the Z direction than the actuator plate  53 . The intermediate plate  52  becomes shorter in dimension in the Y direction than the actuator plate  53 . Therefore, at the both sides in the Y direction of the intermediate plate  52 , there are exposed the both end portions (e.g., the first outside area  81 ) in the Y direction in the actuator plate  53 . In the both end portions in the Y direction in the actuator plate  53 , the portion exposed from the intermediate plate  52  functions as a pressure-bonding area of each of the flexible printed boards  100 ,  101 . 
     In the intermediate plate  52 , a portion which overlaps the penetration part  75   b  of each of the ejection channels  75  in the plan view is provided with a communication hole  130 . The communication hole  130  includes an A column communication hole  130 A communicated with the ejection channel  75 A, and a B column communication hole  130 B communicated with the ejection channel  75 B. The communication hole  130  is communicated with the penetration part  75   b  of corresponding one of the ejection channels  75  at the obverse surface side of the actuator plate  53 . The communication hole  130  is formed to have an oval shape having a longitudinal direction set to the Y direction. The communication hole  130  is shorter in dimension in the Y direction than the penetration part  75   b . In contrast, the communication hole  130  is wider in dimension in the X direction than the penetration part  75   b . It should be noted that the communication hole  130  can be shorter in dimension in the X direction than the penetration part  75   b.    
     At a position overlapping the group separation groove  71  in the plan view in the intermediate plate  52 , there is formed a first open groove  131 . The first open groove  131  opens the group separation groove  71 , and at the same time, exposes the second outside area  86  of the first channel B column  62  and the first outside area  81  of the second channel A column  63 . The first open groove  131  is formed to have a shape like a strip extending in the X direction having an equivalent length to that of the group separation groove  71 . 
     At a position overlapping the column separation groove  72  in the plan view in the intermediate plate  52 , there is formed a second open groove  132 . The second open groove  132  opens at least the column separation groove  72 . The second open groove  132  is formed to have a shape like a strip extending in the X direction having an equivalent length to that of the column separation groove  72 . It should be noted that the length in the Y direction of the second open groove  132  can be narrower or wider than that of the column separation groove  72  as long as there is formed a configuration in which at least a part of the column separation groove  72  is opened through the second open groove  132 . In the present embodiment, the second open groove  132  and the column separation groove  72  are made equivalent in length in the Y direction to each other. 
     As shown in  FIG.  4   , the nozzle plate  51  is fixed to a surface of the intermediate plate  52  with an adhesive or the like. The nozzle plate  51  is made equivalent in width in the Y direction to the intermediate plate  52 . In the present embodiment, the nozzle plate  51  is formed of a resin material such as polyimide so as to have a thickness of about 50 μm. It should be noted that it is possible for the nozzle plate  51  to have a single layer structure or a laminate structure with a metal material (SUS, Ni—Pd, or the like), glass, silicone, or the like besides the resin material. 
     The nozzle plate  51  is provided with four nozzle columns (a first nozzle A column  141 , a first nozzle B column  142 , a second nozzle A column  143 , and a second nozzle B column  144 ) which extend in the X direction and are arranged at intervals in the Y direction. 
     The nozzle columns  141  through  144  each have a plurality of nozzle holes (first nozzle A holes  145 , first nozzle B holes  146 , second nozzle A holes  147 , and second nozzle B holes  148 ) penetrating the nozzle plate  51  in the Z direction. The nozzle holes  145  through  148  are each arranged at intervals in the X direction. Each of the nozzle holes  145  through  148  is formed to have, for example, a taper shape having the inner diameter gradually decreasing in a direction from the reverse side toward the obverse side. The maximum inner diameter of each of the nozzle holes  145  through  148  becomes equivalent to the width in the Y direction of the ejection channel  75 . 
     As shown in  FIG.  6    and  FIG.  9   , the first nozzle A holes  145  are each communicated with a central portion in the Y direction of the ejection channel  75 A in the first channel A column  61  through the A column communication hole (the first communication hole)  130 A. The first nozzle B holes  146  are each communicated with a central portion in the Y direction of the ejection channel  75 B in the first channel B column  62  through the B column communication hole (the second communication hole)  130 B. The second nozzle A holes  147  are each communicated with a central portion in the Y direction of the ejection channel  75 A in the second channel A column  63  through the A column communication hole  130 A. The second nozzle B holes  148  are each communicated with a central portion in the Y direction of the ejection channel  75 B in the second channel B column  64  through the B column communication hole  130 B. Therefore, the non-ejection channels  76  are not communicated with the nozzle holes  145  through  148 , but are covered with the nozzle plate  51  from the obverse surface side. 
     [Operation Method of Printer  1 ] 
     Then, when recording a character, a figure, or the like on the recording target medium P using the printer  1  configured as described above will hereinafter be described. 
     It should be noted that it is assumed that as an initial state, the sufficient ink having colors different from each other is respectively encapsulated in the four ink tanks  4  shown in  FIG.  1   . Further, there is provided the state in which the inkjet heads  5  are filled with the ink in the ink tanks  4  via the ink circulation mechanisms  6 , respectively. 
     In such an initial state, when making the printer  1  operate, the recording target medium P is conveyed toward the +X side while being pinched by the rollers  11 ,  12  of the conveying mechanisms  2 ,  3 . Further, by the carriage  29  moving in the Y direction at the same time, the inkjet heads  5  mounted on the carriage  29  reciprocate in the Y direction. 
     During the reciprocation of the inkjet heads  5 , the ink is arbitrarily ejected toward the recording target medium P from each of the inkjet heads  5 . Thus, it is possible to perform recording of the character, the image, and the like on the recording target medium P. 
     Here, the motion of each of the inkjet heads  5  will hereinafter be described in detail. 
     In such circulating side-shooting type inkjet head  5  as in the present embodiment, first, by making the pressure pump  24  and the suction pump  25  shown in  FIG.  2    operate, the ink is circulated in the circulation flow channel  23 . In this case, the ink circulating through the ink supply tube  21  is supplied into each of the ejection channels  75  through the entrance common ink chambers  120  and the entrance slits  125 . The ink supplied into each of the ejection channels  75  circulates each of the ejection channels  75  in the Y direction. Then, the ink is discharged to the exit common ink chambers  121  through the exit slits  126 , and is then returned to the ink tank  4  through the ink discharge tube  22 . Thus, it is possible to circulate the ink between the inkjet head  5  and the ink tank  4 . 
     Then, when the reciprocation of the inkjet head  5  is started due to the translation of the carriage  29  (see  FIG.  1   ), the drive voltages are applied to the electrodes  95 ,  97  via the flexible printed boards  100 ,  101 . On this occasion, the individual electrode  97  is set at a drive potential Vdd, and the common electrode  95  is set at a reference potential GND to apply the drive voltage between the electrodes  95 ,  97 . Then, a thickness shear deformation occurs in two drive walls  70  partitioning the ejection channel  75 , and the two drive walls  70  each deform so as to protrude toward the non-ejection channel  76 . Specifically, by applying the voltage between the electrodes  95 ,  97 , the drive walls  70  each make a flexural deformation to form a V-shape centering on an intermediate portion in the Z direction. Thus, the volume of the ejection channel  75  increases. Further, since the volume of the ejection channel  75  has increased, the ink retained in the entrance common ink chamber  120  is induced into the ejection channel  75  through the entrance slit  125 . The ink having been induced into the ejection channel  75  propagates inside the ejection channel  75  as a pressure wave. The voltage applied between the electrodes  95 ,  97  is set to zero at the timing when the pressure wave reaches corresponding one of the nozzle holes  145  through  148 . Thus, the drive walls  70  are restored, and the volume of the ejection channel  75  having once increased is restored to the original volume. Due to this operation, the internal pressure of the ejection channel  75  increases to pressurize the ink. As a result, it is possible to record the character, the figure, and the like on the recording target medium P as described above by the ink shaped like a droplet being ejected outside through the communication hole  130  and corresponding one of the nozzle holes  145  through  148 . 
     &lt;Method of Manufacturing Head Chip  50 &gt; 
     Then, a method of manufacturing such a head chip  50  as described above will be described. In the following description, when manufacturing the head chip  50  chip by chip will be described as an example for the sake of convenience.  FIG.  10    is an enlarged side view of a plate assembly  200 . 
     The method of manufacturing the head chip  50  is provided with a stacking step, a protective film formation step, and a nozzle plate bonding step. It should be noted that it is assumed that the processing necessary in advance of the stacking step has already been performed on each of the plates  51  through  54 . 
     In the stacking step, the actuator plate  53 , the cover plate  54 , and the intermediate plate  52  are bonded to one another with an adhesive or the like. On this occasion, the actuator plate  53  and the cover plate  54  are bonded to each other so that the ejection channels  75  in the channel columns  61  through  64  are communicated with the corresponding slits  125 ,  126 . Further, the actuator plate  53  and the intermediate plate  52  are bonded to each other so that the ejection channels  75  in the channel columns  61  through  64  are communicated with the corresponding communication holes  130 . By the actuator plate  53 , the cover plate  54 , and the intermediate plate  52  being bonded to one another, the plate assembly  200  is formed. In this state, the ejection channels  75  are communicated with the outside of the ejection channels  75  through the slits  125 ,  126  and the communication holes  130 . In each of the non-ejection channels  76 , the penetration part  76   a  is communicated with the outside of the non-ejection channel  76  in the outside areas  81 ,  86 , and the open aperture  90   a  is communicated with the outside of the non-ejection channel  76  through the column separation groove  72  and the second open groove  132 . 
     In the protective film formation step, the first protective film  110  is formed in each of the ejection channels  75 , and at the same time, the second protective film  111  is formed on the inner surface of each of the non-ejection channels  76 . The protective films  110 ,  111  are formed by depositing a para-xylylene resin material using, for example, a chemical vapor deposition method (CVD). Specifically, in the state in which the plate assembly  200  is set in a chamber (not shown), a raw material gas to be the formation material of the protective films  110 ,  111  is introduced. On this occasion, the raw material gas is introduced into the ejection channels  75  through the slits  125 ,  126  and the communication holes  130 . In other words, the raw material gas is introduced from the both end portions in the Y direction of each of the ejection channels  75  through the common ink chambers  120 ,  121  and the slits  125 ,  126  (see arrows Q 1   a ). The raw material gas is introduced from the central portion in the Y direction of each of the ejection channels  75  through the communication holes  130  (see arrows Q 1   b ). By the raw material gas introduced into the ejection channels  75  adhering to the inner surfaces of the ejection channels  75 , the first protective films  110  are deposited on the inner surfaces of the ejection channels  75 . 
     Into the non-ejection channels  76 , there is introduced the raw material gas through the penetration parts  76   a  and the communication parts  90 . In other words, the raw material gas is introduced into the non-ejection channels  76  through the portions (the open apertures  53   a ,  53   b ) opened in the outside areas  81 ,  86  out of the penetration parts  76   a  (see arrows Q 2   a ). The raw material gas enters the second open grooves  132  and the column separation grooves  72 , and is then introduced into the non-ejection channels  76  through the open apertures  90   a  (see arrow Q 2   b ). Further, the raw material gas having entered the column separation groove  72  enters the communication grooves  127 , and is then introduced into the non-ejection channels  76  through the open apertures  90   a  from the reverse surface side of the actuator plate  53 . By the raw material gas introduced into the non-ejection channels  76  adhering to the inner surfaces of the non-ejection channels  76 , the second protective films  111  are deposited. It should be noted that in the protective film formation step, it is possible for the protective film to be deposited other portions than the inner surfaces of the channels  75 ,  76  as long as the protective films  110 ,  111  are formed on at least the inner surfaces of the channels  75 ,  76 . 
     Subsequently, in the nozzle plate bonding step, the nozzle plate  51  and the actuator plate  53  are bonded to each other so that the nozzle holes  145  through  148  are communicated with the ejection channels  75  of the corresponding channel columns  61  through  64  through the communication holes  130 . 
     Due to the steps described hereinabove, the head chip  50  is manufactured. 
     It should be noted that the head chip  50  can be manufactured in terms of wafer. When manufacturing the head chips  50  in terms of wafer, an actuator wafer having a plurality of actuator plates  53  connected to each other, a cover wafer having a plurality of cover plates  54  connected to each other, and an intermediate wafer having a plurality of intermediate plates  52  connected to each other are bonded to one another to form a wafer assembly. Subsequently, the protective films  110 ,  111  are provided to the wafer assembly, and then, the wafer assembly is cut to thereby form a plurality of head chips  50 . 
     As described above, in the present embodiment, there is adopted the configuration in which the projective films  110 ,  111  are respectively formed on the inner surfaces of the ejection channels  75  and the non-ejection channels  76  in the first channel A column  61 , and the inner surfaces of the ejection channels  75  and the non-ejection channels  76  in the first channel B column  62  in the same channel group (e.g., the first channel group  66 ). 
     According to this configuration, by the protective films  110 ,  111  being formed on the inner surfaces of the ejection channels  75  and the non-ejection channels  76 , it is possible to prevent the electrodes  95 ,  97  formed on the inner surfaces of the ejection channels  75  and the non-ejection channels  76  from making contact with the ink. Thus, it is possible to prevent the short circuit of the electrodes  95 ,  97  caused by the ink, and thus, it is possible to maintain the excellent ejection performance over a long period of time. 
     In particular, in the present embodiment, in the actuator plate  53 , in the both end portions in the Y direction of the non-ejection channels  76 A in the first channel A column  61 , there are formed the open apertures  53   a ,  90   a A which communicate the inside and the outside of the non-ejection channels  76 A, and at the same time, are capable of introducing the formation material of the second protective films  111  into the non-ejection channels  76 A. In contrast, in the actuator plate  53 , there is adopted the configuration in which in the both end portions in the Y direction of the non-ejection channels  76 B in the first channel B column  62 , there are formed the open apertures  53   b ,  90   a B which communicate the inside and the outside of the non-ejection channels  76 B, and at the same time, are capable of introducing the formation material of the second protective films  111  into the non-ejection channels  76 B. 
     According to this configuration, by introducing the formation material of the second protective films  111  into the non-ejection channels  76  through the open apertures  53   a ,  90   a A and the open apertures  53   b ,  90   a B, it is possible to effectively form the second protective films  111  also on the inner surfaces of the non-ejection channels  76 . 
     As a result, it is possible to prevent the short circuit or the like of the electrodes formed on the inner surfaces of the non-ejection channels  76  caused by, for example, the ink having entered the non-ejection channels  76 . 
     Moreover, in the present embodiment, the formation material of the first protective films  110  is introduced into the ejection channels  75  through the slits  125 ,  126  and the communication holes  130 , and the formation material of the second protective films  111  is introduced into the non-ejection channels  76  through the open apertures  53   a ,  53   b , and  90   a . Thus, it is possible to effectively form the protective films  110 ,  111  on the inner surfaces of the ejection channels  75  and the inner surfaces of the non-ejection channels  76 . 
     In the present embodiment, there is adopted the configuration in which the actuator plate  53  and the intermediate plate  52  are provided with the column separation grooves  72  and the second open grooves  132  for communicating the open apertures  90   a A of the non-ejection channels  76 A in the first channel A column  61  and the open apertures  90   a B of the non-ejection channels  76 B in the first channel B column  62  with each other. 
     According to this configuration, the raw material gas of the second protective films  111  is introduced into the non-ejection channels  76  via the open apertures  90   a  from the column separation grooves  72  and the second open grooves  132 . Thus, it is possible to efficiently form the second protective films  111  compared to when introducing the formation material of the protective films individually into the non-ejection channels  76  through the respective open apertures  90   a.    
     In the present embodiment, there is adopted the configuration in which the cover plate  54  is provided with the communication grooves  127  communicated with the column separation groove  72 . 
     According to this configuration, in the plate assembly  200 , since it is possible to reduce the pressure loss in the space connected to the open apertures  90   a , it is possible to efficiently introduce the raw material gas of the second protective films  111  into the non-ejection channels  76  through the open apertures  90   a.    
     In the present embodiment, the width in the X direction in the communication groove  127  is made wider than that of the column separation groove  72 , and the communication grooves  127  are communicated with the open apertures  90   a  from the reverse surface side of the actuator plate  53 . 
     According to this configuration, the raw material gas of the second protective film  111  having entered the communication grooves  127  through the column separation grooves  72  is introduced into the non-ejection channels  76  via the open apertures  90   a  from the reverse surface side of the actuator plate  53 . Thus, the raw material gas of the second protective films  111  is introduced into the non-ejection channels  76  directly through the column separation grooves  72  or indirectly through the communication grooves  127 . As a result, it is possible to efficiently form the second protective films  111  on the inner surfaces of the non-ejection channels  76 . 
     In the present embodiment, there is adopted the configuration in which the beam parts  128  are each disposed between the entrance common ink chambers  120  adjacent to each other in the cover plate  54 . 
     According to this configuration, it becomes easy to ensure the strength of the cover plate  54  with the beam parts  128 . Therefore, when bonding the actuator plate  53  and the cover plate  54  to each other, the bonding load can effectively be applied between the actuator plate  53  and the cover plate  54 . As a result, it is possible to surely bond the actuator plate  53  and the cover plate  54  to each other to prevent the leakage of the ink through an area between the actuator plate  53  and the cover plate  54 . 
     Further, by providing the beam parts  128  with the communication grooves  127 , it becomes easy to ensure the depth of the communication grooves  127 . Therefore, it is possible to efficiently introduce the raw material gas of the second protective films  111  into the non-ejection channels  76  through the open apertures  90   a.    
     In the present embodiment, the uprise part  76   b  in the first channel A column  61  traverses the column separation groove  72  in the Y direction, and at the same time, a communication portion with the column separation groove  72  constitutes the open aperture  90   a A, and the uprise part  76   b  in the first channel B column  62  traverses the column separation groove  72  in the Y direction, and at the same time, a communication portion with the column separation groove  72  constitutes the open aperture  90   a B. 
     According to this configuration, it is easy to ensure the aperture area of the open aperture compared to when the column separation groove  72  is communicated in the end portion of the uprise part  76   b . Thus, it is possible to efficiently introduce the raw material gas of the second protective films  111  into the non-ejection channels  76  through the open apertures  90   a.    
     In the inkjet head  5  and the printer  1  according to the present embodiment, since the head chip  50  described above is provided, it is possible to prevent the short circuit of the electrodes with the ink, and thus, it is possible to maintain the excellent ejection performance over a long period of time. 
     Second Embodiment 
     In the head chip  50  shown in  FIG.  11   , the communication grooves  127  are each disposed in the central portion in the Y direction of the beam part  128 . A width D 1  in the Y direction of the communication groove  127  is narrower than a width D 2  in the Y direction of the beam part  128 . Therefore, a portion located outside the communication groove  127  on the surface of the beam part  128  functions as a pressure receiving area T 1  bonded to the actuator plate  53 . It should be noted that a bottom surface of the entrance common ink chamber  120  is located at the reverse surface side of the vertex surface of the communication groove  127 . Therefore, the entrance common ink chamber  120  and the communication groove  127  are disposed so as to be shifted in the Z direction from each other (do not overlap each other). 
     In the present embodiment, in the beam part  128 , the portion located at the outer side of the communication groove  127  is provided with the pressure receiving area T 1 . The pressure receiving area T 1  functions as a pressure receiving surface for receiving the load which acts between the actuator plate  53  and the cover plate  54  when bonding the actuator plate  53  and the cover plate  54  to each other. Thus, it is possible to effectively apply the bonding load between the actuator plate  53  and the cover plate  54 . As a result, it is possible to more surely bond the actuator plate  53  and the cover plate  54  to each other. 
     As shown in  FIG.  12   , it is possible for the entrance common ink chamber  120  and the communication groove  127  to overlap each other in the Z direction. Thus, it becomes easy to ensure the depth of the communication groove  127 , and therefore, it is possible to efficiently introduce the raw material gas of the second protective films  111  into the non-ejection channels  76  through the open apertures  90   a.    
     It should be noted that the scope of the present disclosure is not limited to the embodiments described above, but a variety of modifications can be applied within the scope or the spirit of the present disclosure. 
     For example, in the embodiments described above, the description is presented citing the inkjet printer  1  as an example of the liquid jet recording device, but the liquid jet recording device is not limited to the printer. For example, a facsimile machine, an on-demand printing machine, and so on can also be adopted. 
     In the embodiments described above, the description is presented citing the configuration (a so-called shuttle machine) in which the inkjet head moves with respect to the recording target medium when performing printing as an example, but this configuration is not a limitation. The configuration related to the present disclosure can be adopted as the configuration (a so-called stationary head machine) in which the recording target medium is moved with respect to the inkjet head in the state in which the inkjet head is fixed. 
     In the embodiments described above, there is described when the recording target medium P is paper, but this configuration is not a limitation. The recording target medium P is not limited to paper, but can also be a metal material or a resin material, and can also be food or the like. 
     In the embodiments described above, there is described the configuration in which the liquid jet head is installed in the liquid jet recording device, but this configuration is not a limitation. Specifically, the liquid to be jetted from the liquid jet head is not limited to what is landed on the recording target medium, but can also be, for example, a medical solution to be blended during a dispensing process, a food additive such as seasoning or a spice to be added to food, or fragrance to be sprayed in the air. 
     In the embodiments described above, there is described the configuration in which the Z direction coincides with the gravitational direction, but this configuration is not a limitation, and it is also possible to set the Z direction along the horizontal direction. 
     In the embodiments described above, there is adopted the configuration in which the non-ejection channels  76  in the first channel A column  61  and the non-ejection channels  76  in the first channel B column  62  open in the common column separation groove  72  in the first channel A column  61  and the first channel B column  62  (or the second channel A column  63  and the second channel B column  64 ). It should be noted that it is possible for the non-ejection channels  76  in the first channel A column  61  and the non-ejection channels  76  in the first channel B column  62  to communicate the inside and the outside of the non-ejection channels  76  with each other through the respective grooves separated from each other. 
     In the embodiments described above, there is described the configuration in which the width of the communication groove  127  is wider than the width of the column separation groove  72  in the cover plate  54 , but the width of the communication groove  127  can be wider or narrower than the width of the column separation groove  72 . Further, it is possible for the cover plate  54  to have a configuration not provided with the communication grooves  127 . 
     In the embodiments described above, the non-ejection channels  76  can be communicated through other portions than the open apertures  53   a ,  90   a  as long as the non-ejection channels are communicated with the outside in the both end portions. 
     In the embodiments described above, the description is presented citing the protective films for protecting the electrodes as an example, but it is possible to form the protective film irrespective of the presence or absence of the electrodes. 
     In the embodiments described above, there is described the configuration in which the entrance common ink chamber  120  is disposed for each of the channel columns, but this configuration is not a limitation. For example, as shown in  FIG.  13   , it is possible to share the single entrance common ink chamber  120  with respect to the channel columns  61 ,  62  adjacent to each other. In this case, in the entrance common ink chamber  120 , there open the entrance slits  125  communicated with the ejection channels  75 A in one channel column  61  and the entrance slits  125  communicated with the ejection channels  75 B in another channel column  62 . In such a configuration, it is possible to form the communication groove  127  at the position (the portion located at the −Z side of the entrance common ink chamber  120 ) overlapping the column separation groove  72  in the plan view on the surface of the cover plate  54 . 
     Besides the above, it is arbitrarily possible to replace the constituents in the embodiments described above with known constituents within the scope or the spirit of the present disclosure, and it is also possible to arbitrarily combine the modified examples described above.