Patent Publication Number: US-9895890-B2

Title: Ink jet recording apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of PCT International Application No. PCT/JP2015/083945 filed on Dec. 3, 2015, which claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2015-048253 filed on Mar. 11, 2015. Each of the above application(s) is hereby expressly incorporated by reference, in its entirety, into the present application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an ink jet recording apparatus, and more particularly, to a line-type ink jet recording apparatus on which long ink jet heads of which length in a nozzle arrangement direction is longer than length in a direction orthogonal to the nozzle arrangement direction are mounted. 
     2. Description of the Related Art 
     Ink jet heads, which have a length corresponding to the width of a medium as a recording target, are mounted on a line-type ink jet recording apparatus that can record a desired image on a medium by single pass. Accordingly, as the width of a medium as a recording target increases, longer ink jet heads are mounted on the line-type ink jet recording apparatus. 
     Generally, an ink jet head of which the length in the longitudinal direction is long is installed at a predetermined position in the apparatus while both end portions of the ink jet head in the longitudinal direction are supported. 
     However, in a case in which the ink jet head is supported in this way, the ink jet head is bent by its own weight and warpage occurs. For this reason, since a deviation in ink landing positions is generated due to this warpage, there is a problem that the quality of an image deteriorates. 
     Accordingly, JP1991-227634A (JP-H03-227634A) proposes a method of correcting bending, which includes a step of providing warpage correction means on a mount on which an ink jet head is installed and a step of applying a force to the ink jet head in a direction in which warpage is cancelled by the warpage correction means. 
     SUMMARY OF THE INVENTION 
     However, in a structure in which the warpage correction means is provided on the mount as in JP1991-227634A (JP-H03-227634A), the warpage correction means for each of the ink jet heads should be installed on the mount in a case in which a plurality of ink jet heads are installed on the mount. For this reason, there is a drawback that a part on which the ink jet heads are to be installed increases in size. 
     The invention has been made in consideration of the above-mentioned circumstances, and an object of the invention is to provide an ink jet recording apparatus that can correct bending of an ink jet head with a compact structure. 
     (1) An ink jet recording apparatus comprising: a plurality of recording units each of which comprises a long ink jet head and an ink supply section supplying ink to the ink jet head; a plurality of supporting frames each of which comprises a first supporting frame supporting the ink jet head and a second supporting frame supporting at least a part of the ink supply section; a mount that comprises a plurality of first supporting frame supports supporting both ends of the first supporting frames in a longitudinal direction and a plurality of second supporting frame supports supporting the second supporting frames; and bending correction unit that are provided on the second supporting frames and apply pressing forces or tensile forces to at least a part of the first supporting frames to correct bending of the first supporting frames in a case in which the first supporting frames are supported by the first supporting frame supports. 
     According to this aspect, the supporting frame is provided for each of the recording units. The supporting frame includes the first supporting frame that supports the ink jet head and the second supporting frame that supports at least a part of the ink supply section. The first supporting frames are mounted on the mount while both ends of each first supporting frame in the longitudinal direction are supported by the first supporting frame supports provided on the mount. The second supporting frames are mounted on the mount while being supported by the second supporting frame supports provided on the mount. Each of the second supporting frames is provided with the bending correction unit. The bending correction unit apply pressing forces or tensile forces to at least a part of the first supporting frames to correct the bending of the first supporting frames. Since the bending correction unit is provided on the second supporting frame, a part on which the ink jet heads are to be installed can be made compact relative to the mount. Further, since the ink jet head is supported independently of the ink supply section, the support of the ink jet head can be reduced in weight. Accordingly, the bending of the ink jet head caused by its own weight can be suppressed. 
     (2) The ink jet recording apparatus according to (1),
         wherein the ink jet head includes a plurality of joined head modules.       

     According to this aspect, the ink jet head includes a plurality of joined head modules. Since the plurality of head modules are joined to form one ink jet head, an ink jet head, which is long in the longitudinal direction, can be easily manufactured. 
     (3) The ink jet recording apparatus according to (1) or (2),
         wherein the first supporting frame supports are arranged in the shape of an arc along an arc-shaped transport path of a medium that is transported along the transport path.       

     According to this aspect, the first supporting frame supports are arranged in the shape of an arc along an arc-shaped transport path of a medium that is transported along the transport path. This transport path is formed, for example, in a case in which a medium is transported while being wound around the peripheral surface of the rotating drum. Further, in a case in which the first supporting frame supports are arranged in the shape of an arc along the arc-shaped transport path, the ink jet heads are obliquely installed at different angles. 
     (4) The ink jet recording apparatus according to any one of (1) to (3),
         wherein the first and second supporting frames of the supporting frame are connected to each other by a connecting member.       

     According to this aspect, the first and second supporting frames are connected to each other by the connecting member. Accordingly, when being attached to or detached from the mount, the first and second supporting frames can be integrally attached to or detached from the mount. 
     (5) The ink jet recording apparatus according to any one of (1) to (4),
         wherein the bending correction unit comprise springs, and apply pressing forces or tensile forces, which are generated by the springs, to the first supporting frames.       

     According to this aspect, the bending correction unit comprise springs, and pressing forces or tensile forces, which are generated by the springs, are applied to the first supporting frames. 
     (6) The ink jet recording apparatus according to (5),
         wherein the bending correction unit further comprise levers, and apply pressing forces or tensile forces, which are generated by the springs, to the first supporting frames through the levers.       

     According to this aspect, pressing forces or tensile forces, which are generated by the springs, are applied to the first supporting frames through the levers. Accordingly, large pressing forces or large tensile forces can be applied to the first supporting frames by small forces of the springs. 
     (7) The ink jet recording apparatus according to any one of (1) to (4),
         wherein the bending correction unit comprise first springs each of which pulls one end of the first supporting frame in a lateral direction and second springs each of which pulls the other end of the first supporting frame in the lateral direction.       

     According to this aspect, the bending correction unit comprise the first springs and the second springs. The first spring pulls one end of the first supporting frame in the lateral direction, and the second spring pulls the other end of the first supporting frame in the lateral direction. Since it is possible to easily control a force to be applied to the first supporting frame by adjusting the tensile force that is generated by the first spring and the tensile force that is generated by the second spring, bending can be appropriately corrected. Particularly, bending can be appropriately corrected in a case in which the ink jet heads are obliquely installed. 
     (8) The ink jet recording apparatus according to any one of (1) to (6),
         wherein the bending correction unit apply tensile forces to the first supporting frames of the supporting frames that are adjacently disposed.       

     According to this aspect, the bending correction unit, which is provided on the second supporting frame of each supporting frame, applies a tensile force to the first supporting frame of the supporting frame that is adjacently disposed. Accordingly, it is possible to appropriately apply a tensile force to the first supporting frame by effectively using a space between the respective supporting frames. 
     (9) The ink jet recording apparatus according to any one of (1) to (8),
         wherein the first and second supporting frames of the supporting frames are arranged in series in an ink jetting direction of the ink jet head supported by the first supporting frame.       

     According to this aspect, the first and second supporting frames are arranged in series in an ink jetting direction of the ink jet head supported by the first supporting frame. For example, in a case in which ink is jetted vertically downward from the ink jet head supported by the first supporting frame, the second supporting frame is disposed immediately above the first supporting frame. Accordingly, since an interval between the adjacent supporting frames can be made short, a part on which the ink jet heads are to be installed can be made compact. 
     (10) The ink jet recording apparatus according to any one of (1) to (9), further comprising:
         a carriage on which the mount is mounted.       

     According to this aspect, the mount is mounted on the carriage. Accordingly, the plurality of ink jet heads mounted on the mount can be moved integrally. 
     According to the invention, it is possible to correct the bending of an ink jet head with a compact structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view showing the schematic structure of an ink jet recording apparatus. 
         FIG. 2  is a plan view of the ink jet recording apparatus shown in  FIG. 1 . 
         FIG. 3  is a diagram showing the arrangement relationship of ink jet heads with respect to an image recording drum. 
         FIG. 4  is a block diagram showing the schematic configuration of a control system of the ink jet recording apparatus. 
         FIG. 5  is a perspective view showing the structure of the ink jet head. 
         FIG. 6  is a plan view of a nozzle surface of the ink jet head. 
         FIG. 7  is an enlarged plan view of a part of a nozzle arrangement region. 
         FIG. 8  is a diagram showing the schematic configuration of an ink supply section. 
         FIG. 9  is a front view of a mount on which the ink jet heads are mounted. 
         FIG. 10  is a cross-sectional view taken along line  10 - 10  of  FIG. 9 . 
         FIG. 11  is a front view showing the schematic structure of a bending correction mechanism. 
         FIG. 12  is an enlarged view of the bending correction mechanism. 
         FIG. 13  is a diagram showing the schematic structure of the bending correction mechanism in a case in which a plurality of portions of a first supporting frame are pressed to correct bending. 
         FIG. 14  is a front view showing a second embodiment of the bending correction mechanism. 
         FIG. 15  is a front view showing a third embodiment of the bending correction mechanism. 
         FIG. 16  is a front view showing a schematic structure in a case in which a tensile force is applied to the first supporting frame from a bending correction mechanism provided on an adjacent supporting frame to correct the bending of a first supporting frame. 
         FIG. 17  is a diagram showing a schematic structure in a case in which a pressing force is applied to a first supporting frame from a bending correction mechanism provided on an adjacent supporting frame. 
         FIG. 18  is a front view showing a fifth embodiment of the bending correction mechanism. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the invention will be described in detail below with reference to the accompanying drawings. 
     &lt;&lt;Entire Structure of Ink Jet Recording Apparatus&gt;&gt; 
       FIG. 1  is a front view showing the schematic structure of an ink jet recording apparatus. Further,  FIG. 2  is a plan view of the ink jet recording apparatus shown in  FIG. 1 . 
     An ink jet recording apparatus  1  of this embodiment is a line-type ink jet recording apparatus that records a color image on a sheet of paper by a single-pass method with line-type ink jet heads. Particularly, the ink jet recording apparatus  1  of this embodiment is an ink jet recording apparatus that records an image on a general-purpose printing sheet with aqueous ink. Here, aqueous ink means ink in which a color material, such as dye or a pigment, is dissolved or dispersed in water and a solvent soluble in water. Further, a general-purpose printing sheet means not a so-called exclusive sheet for ink jet but a sheet using cellulose as a main component, such as coated paper, which is generally used for offset printing and the like. 
     As shown in  FIGS. 1 and 2 , the ink jet recording apparatus  1  of this embodiment mainly includes: a sheet feeding section  10  that feeds a sheet P; a treatment liquid applying section  20  that applies treatment liquid to the sheet P fed from the sheet feeding section  10 ; a treatment liquid drying section  30  that performs processing for drying the sheet P to which the treatment liquid has been applied; an image recording section  40  that records a color image on the sheet P, which has been subjected to drying processing, by an ink jet method; an ink drying section  50  that performs processing for drying the sheet P on which the image has been recorded; a collection section  60  that collects the sheet P having been subjected to drying processing; and a maintenance section  70  that performs the maintenance of the ink jet heads of the image recording section  40 . 
     &lt;Sheet Feeding Section&gt; 
     The sheet feeding section  10  automatically feeds sheets P one by one. As shown in  FIGS. 1 and 2 , the sheet feeding section  10  mainly includes a sheet feeding device  12 , a feeder board  14 , and a sheet feed drum  16 . 
     The sheet feeding device  12  sequentially takes out the sheets P, which are set on a sheet feed tray  12 A in the form of a bundle, from the top of the bundle one by one and feeds the sheets P to the feeder board  14 . 
     The feeder board  14  receives the sheets P that are fed from the sheet feeding device  12  and transfers the received sheets P to the sheet feed drum  16 . 
     The sheet feed drum  16  receives the sheets P fed from the feeder board  14  and transfers the received sheets P to the treatment liquid applying section  20 . 
     &lt;Treatment Liquid Applying Section&gt; 
     The treatment liquid applying section  20  applies treatment liquid to the sheet P. The treatment liquid is liquid having a function to allow a color material component, which is contained in ink, to aggregate, to insolubilize the color material component, or to thicken the color material component. Since the treatment liquid is applied to the sheet P, a high-quality image can be recorded even in a case in which a general-purpose printing sheet is used. 
     As shown in  FIGS. 1 and 2 , the treatment liquid applying section  20  mainly includes a treatment liquid applying drum  22  that transports a sheet P, and a treatment liquid applying device  24  that applies treatment liquid to the sheet P transported by the treatment liquid applying drum  22 . 
     The treatment liquid applying drum  22  receives the sheet P from the sheet feed drum  16  of the sheet feeding section  10 , and transfers the received sheet P to the treatment liquid drying section  30 . The treatment liquid applying drum  22  includes a gripper  23  provided on the peripheral surface thereof, and transports the sheet P while winding the sheet P around the peripheral surface thereof by gripping a front end of the sheet P by the gripper  23  and rotating. Here, the front end of the sheet P means the front end portion of the sheet P in a transport direction. 
     The treatment liquid applying device  24  applies treatment liquid to the sheet P that is transported by the treatment liquid applying drum  22 . The treatment liquid applying device  24  includes an application roller, and applies the treatment liquid to the recording surface of the sheet P while making the application roller be in contact with the recording surface of the sheet P. Here, the recording surface of the sheet P means the surface of the sheet P on which an image is to be recorded. 
     The treatment liquid applying section  20  has the above-mentioned structure. While a sheet P is transported by the treatment liquid applying drum  22 , treatment liquid is applied to the recording surface. 
     &lt;Treatment Liquid Drying Section&gt; 
     The treatment liquid drying section  30  performs processing for drying the sheets P to which treatment liquid has been applied. The treatment liquid drying section  30  mainly includes a treatment liquid drying drum  32  that transports sheets P, and a plurality of hot air blowers  34  that blow hot air to the recording surfaces of the sheets P transported by the treatment liquid drying drum  32 . 
     The treatment liquid drying drum  32  receives the sheet P from the treatment liquid applying drum  22  of the treatment liquid applying section  20 , and transfers the received sheet P to the image recording section  40 . The treatment liquid drying drum  32  is formed of a frame body formed in a cylindrical shape, and includes grippers  33  provided on the peripheral surface thereof. The treatment liquid drying drum  32  transports sheets P by gripping the front ends of the sheets P by the grippers  33  and rotating. 
     The hot air blowers  34  are installed in the treatment liquid drying drum  32 . The hot air blowers  34  blow hot air to the sheets P transported by the treatment liquid drying drum  32 . Hot air, which is blown from the hot air blowers  34 , is blown to the recording surfaces of the sheets P. Accordingly, treatment liquid is dried. 
     The treatment liquid drying section  30  has the above-mentioned structure. While sheets P are transported by the treatment liquid drying drum  32 , hot air is blown to the recording surfaces of the sheets and the sheets P are subjected to drying processing. 
     &lt;Image Recording Section&gt; 
     The image recording section  40  records a color image on the sheet P with inks having four colors of cyan (C), magenta (M), yellow (Y), and black (K). As shown in  FIG. 1 , the image recording section  40  mainly includes an image recording drum  42  that transports sheets P, a head unit  100 , and a scanner  48  that reads an image recorded on the sheet P. 
     The image recording drum  42  receives the sheets P from the treatment liquid drying drum  32  of the treatment liquid drying section  30 , and transfers the received sheets P to the ink drying section  50 . The image recording drum  42  includes grippers  43  provided on the peripheral surface thereof, and transports the sheets P while winding the sheets P around the peripheral surface thereof by gripping the front ends of the sheets P by the grippers  43  and rotating. Further, the image recording drum  42  includes a suction mechanism (not shown) and transports the sheets P while making the sheets P be sucked on the peripheral surface thereof. Negative pressure is used to make the sheets P be sucked. The peripheral surface of the image recording drum  42  is provided with a plurality of suction holes. The suction mechanism makes the sheets P be sucked on the peripheral surface of the image recording drum  42  by sucking air from the inside of the image recording drum  42  through the suction holes. 
     The head unit  100  includes an ink jet head  110 C that jets cyan ink droplets, an ink jet head  110 M that jets magenta ink droplets, an ink jet head  110 Y that jets yellow ink droplets, and an ink jet head  110 K that jets black ink droplets. Each of the ink jet heads  110 C,  110 M,  110 Y, and  110 K is formed of a line-type ink jet head that can record a desired image on the sheet P, which is transported by the image recording drum  42 , by single pass. Further, each of the ink jet heads  110 C,  110 M,  110 Y, and  110 K includes a plurality of joined head modules. This will be described in detail below. 
     The respective ink jet heads  110 C,  110 M,  110 Y, and  110 K are arranged at regular intervals along a transport path of the sheet P that is transported by the image recording drum  42 . 
       FIG. 3  is a diagram showing the arrangement relationship of the ink jet heads with respect to the image recording drum. 
     In  FIG. 3 , reference letter O denotes the center of rotation of the image recording drum  42  and reference letter PP denotes the transport path of the sheet P that is transported by the image recording drum  42 . Further, reference letter VL denotes a vertical line passing through the center O of rotation of the image recording drum  42 , and reference letter HL denotes a horizontal line passing through the center O of rotation of the image recording drum  42 . Furthermore, an arrow denoted by reference letter PD represents the transport direction of the sheet P that is transported by the image recording drum  42 , and an arrow denoted by reference letter RD represents the rotational direction of the image recording drum  42 . 
     Since the transport path PP of the sheet P, which is transported by the image recording drum  42 , is formed in the shape of an arc as shown in  FIG. 3 , the respective ink jet heads  110 C,  110 M,  110 Y, and  110 K are arranged in the shape of an arc at regular intervals along the arc-shaped transport path PP. Particularly, in the ink jet recording apparatus  1  of this embodiment, four ink jet heads  110 C,  110 M,  110 Y, and  110 K are arranged in the shape of an arc so as to be symmetrical with respect to the vertical line VL passing through the center O of rotation of the image recording drum  42 . 
     The ink jet heads  110 C,  110 M,  110 Y, and  110 K include nozzle surfaces  112 C,  112 M,  112 Y, and  112 K at the tips thereof, respectively; and vertically jet ink droplets to the sheet P, which is transported by the image recording drum  42 , from nozzles provided on the nozzle surfaces  112 C,  112 M,  112 Y, and  112 K. 
     Here, in a case in which straight lines, which pass through the centers of the nozzle surfaces  112 C,  112 M,  112 Y, and  112 K of the ink jet heads  110 C,  110 M,  110 Y, and  110 K and are perpendicular to the nozzle surfaces  112 C,  112 M,  112 Y, and  112 K, are denoted by Lc, Lm, Ly, and Lk, respectively, the respective ink jet heads  110 C,  110 M,  110 Y, and  110 K are arranged so that the straight lines Lc, Lm, Ly, and Lk perpendicular to the nozzle surfaces  112 C,  112 M,  112 Y, and  112 K pass through the center O of rotation of the image recording drum  42  and are arranged at regular angular intervals. 
     Further, the respective ink jet heads  110 C,  110 M,  110 Y, and  110 K are arranged so that the nozzle surfaces  112 C,  112 M,  112 Y, and  112 K are positioned at positions having a constant height from the peripheral surface of the image recording drum  42 . 
     The ink jet heads  110 C,  110 M,  110 Y, and  110 K, which are arranged in this way, are arranged so that the nozzle surfaces  112 C,  112 M,  112 Y, and  112 K are inclined with respect to a horizontal plane at different angles. 
     The respective ink jet heads  110 C,  110 M,  110 Y, and  110 K are mounted on a mount (not shown) and form one head unit  100 . The mount is mounted on a carriage that moves between the image recording section  40  and the maintenance section  70 . 
     A structure for supporting the ink jet heads  110 C,  110 M,  110 Y, and  110 K by the mount will be described in detail below. 
     The scanner  48  reads the image that is recorded on the sheet P by the ink jet heads  110 C,  110 M,  110 Y, and  110 K. 
     The image recording section  40  has the above-mentioned structure. While the sheet P is transported by the image recording drum  42 , ink droplets having the respective colors of cyan, magenta, yellow, and black are jetted to the recording surface from the ink jet heads  110 C,  110 M,  110 Y, and  110 K of the head unit  100  and a color image is recorded on the recording surface. The image recorded on the sheet P is read by the scanner  48  as necessary. 
     &lt;Ink Drying Section&gt; 
     The ink drying section  50  performs processing for drying the sheet P on which the image has been recorded by the image recording section  40 . The ink drying section  50  is an example of a sheet drying device that is assembled to the ink jet recording apparatus. 
     As shown in  FIGS. 1 and 2 , the ink drying section  50  mainly includes a chain delivery  52  that transports sheets P, sheet guides  54  that guide the transport of the sheets P, and a hot air blowing unit  56  that blows hot air to the sheets P transported by the chain delivery  52 . 
     The chain delivery  52  receives the sheets P from the image recording drum  42  of the image recording section  40 , and transfers the received sheets P to the collection section  60 . The chain delivery  52  includes a pair of endless chains  52 A traveling along a prescribed travel path, grips the front ends of the sheets P by grippers  52 B provided on the pair of chains  52 A, and transports the sheets P along a prescribed transport path. The grippers  52 B are provided on the chains  52 A at regular intervals. 
     The sheet guides  54  guide the sheets P that are transported by the chain delivery  52 . The sheet guide  54  has a flat guide surface. The sheet P, which is transported by the chain delivery  52 , is transported while sliding on the guide surface. 
     The hot air blowing unit  56  blows hot air to the recording surface of the sheets P, which is transported by the chain delivery  52 , and dries ink. The hot air blowing unit  56  includes a plurality of nozzles arranged along the transport path of the sheet P, and blows hot air to the sheets P, which are transported by the chain delivery  52 , from the nozzles. 
     The ink drying section  50  has the above-mentioned structure. While sheets P are transported by the chain delivery  52 , hot air blown from the hot air blowing unit  56  is blown to the recording surfaces of the sheets and the sheets P are subjected to drying processing. 
     &lt;Collection Section&gt; 
     The collection section  60  collects sheets P, which are sequentially discharged, in one place. As shown in  FIGS. 1 and 2 , the collection section  60  includes a collection device  62  that receives and collects sheets P transported from the ink drying section  50  by the chain delivery  52 . 
     The chain delivery  52  releases the sheets P at a predetermined collection position. The collection device  62  includes a collection tray  62 A, receives the sheets P released from the chain delivery  52 , and collects the sheets P on the collection tray  62 A in the form of a bundle. 
     &lt;Maintenance Section&gt; 
     The maintenance section  70  performs the maintenance of the ink jet heads  110 C,  110 M,  110 Y, and  110 K of the image recording section  40 . As shown in  FIG. 2 , the maintenance section  70  mainly includes: a cap device  72  that covers the nozzle surfaces of the ink jet heads  110 C,  110 M,  110 Y, and  110 K with caps; and a cleaning device  74  that wipes and cleans the nozzle surfaces of the ink jet heads  110 C,  110 M,  110 Y, and  110 K. 
     The cap device  72  includes caps  72 C,  72 M,  72 Y, and  72 K for the ink jet heads  110 C,  110 M,  110 Y, and  110 K, respectively. The caps  72 C,  72 M,  72 Y, and  72 K individually cover the nozzle surfaces of the corresponding ink jet heads  110 C,  110 M,  110 Y, and  110 K. 
     Capping is performed after the ink jet heads  110 C,  110 M,  110 Y, and  110 K are moved to a predetermined cap position. As described above, the ink jet heads  110 C,  110 M,  110 Y, and  110 K are provided so as to be capable of being moved by the carriage. 
     In  FIG. 2 , reference letter D 1  denotes a direction in which the ink jet heads  110 C,  110 M,  110 Y, and  110 K are moved by the carriage. The ink jet heads  110 C,  110 M,  110 Y, and  110 K are horizontally moved in parallel with the rotation axis of the image recording drum  42  by the carriage. The ink jet heads  110 C,  110 M,  110 Y, and  110 K are provided so as to be capable of being moved between the cap position and a recording position by the movement of the carriage. When being positioned at the recording position, the ink jet heads  110 C,  110 M,  110 Y, and  110 K are disposed on the transport path of the sheet P that is transported by the image recording drum  42 . Further, when being positioned at the cap position, the ink jet heads  110 C,  110 M,  110 Y, and  110 K are disposed at positions where the caps  72 C,  72 M,  72 Y, and  72 K are installed. 
     The cleaning device  74  includes cleaners  74 C,  74 M,  74 Y and  74 K that individually clean the nozzle surfaces of the respective ink jet heads  110 C,  110 M,  110 Y, and  110 K. Each of the cleaners  74 C,  74 M,  74 Y and  74 K includes a wiping member that wipes the nozzle surface. The wiping member is formed of, for example, a blade or a web and is provided to be capable of moving forward and backward with respect to the nozzle surface. The cleaning device  74  is disposed on the movement path of the ink jet heads  110 C,  110 M,  110 Y, and  110 K that are moved by the carriage. While each of the ink jet heads  110 C,  110 M,  110 Y, and  110 K is moved to the recording position from the cap position, the wiping member is in pressure contact with the nozzle surface and the nozzle surface is wiped. 
     The maintenance section  70  has the above-mentioned structure. As described above, capping performed by the cap device  72  is performed by the movement of the ink jet heads  110 C,  110 M,  110 Y, and  110 K to the cap position. Capping is performed in a case in which the use of the ink jet heads  110 C,  110 M,  110 Y, and  110 K stops for a prescribed time or over, such as when a power source is turned off or when the ink jet heads are in a standby state. Further, purging, preliminary jetting, or the like, which is an example of maintenance, is also performed by the cap device  72 . 
     The cleaning of the nozzle surfaces, which is performed by the cleaning device  74 , is performed by the movement of the ink jet heads  110 C,  110 M,  110 Y, and  110 K to the recording position from the cap position. The respective cleaners  74 C,  74 M,  74 Y and  74 K of the cleaning device  74  make the wiping members be in pressure contact with the nozzle surfaces of the ink jet heads  110 C,  110 M,  110 Y, and  110 K, which are being moved to the recording position from the cap position, and wipe the nozzle surfaces by the wiping members. 
     The maintenance is automatically performed at a timing that is set in advance. Further, the maintenance is forcibly performed according to an instruction sent from an operator. A timing at which the maintenance to be automatically performed is performed is prescribed according to the type of maintenance. The timing at which the maintenance to be automatically performed is prescribed by time having passed, the number of printed sheets, or the like from the previous maintenance. 
     &lt;&lt;Control System of Ink Jet Recording Apparatus&gt;&gt; 
       FIG. 4  is a block diagram showing the schematic configuration of a control system of the ink jet recording apparatus. 
     As shown in  FIG. 4 , the ink jet recording apparatus  1  includes a computer  200  as a control section. All operation of the ink jet recording apparatus  1  is controlled by the computer  200 . That is, all processings, such as the feeding of a sheet from the sheet feeding section  10 , the transport of the fed sheet, the application of treatment liquid in the treatment liquid applying section  20 , the drying of the sheet P in the treatment liquid drying section  30 , the recording of an image in the image recording section  40 , the reading of the recorded image, the drying of the sheet P in the ink drying section  50 , the discharge of the sheet P, and the collection of the sheet P in the collection section  60 , are performed under the control of the computer  200 . Further, the maintenance is also performed under the control of the computer  200 . 
     The computer  200  functions as a control section that controls the respective sections of the ink jet recording apparatus  1  by executing predetermined control programs. 
     A communication section  202  that is used to communicate with an external device, an operation section  204  that is used to operate the ink jet recording apparatus  1 , a display section  206  that is used to display various kinds of information, a storage section  208  that is used to store various data, and the like are connected to the computer  200 . 
     The operation section  204  is formed of, for example, operation buttons or a keyboard, a mouse, a touch panel, or the like. The display section  206  is formed of, for example, a display device, such as a liquid crystal display. The storage section  208  is formed of, for example, a storage device, such as a hard disk drive. The control programs to be executed by the computer  200 , various data, and the like are stored in the storage section  208 . Further, image data as an object to be recorded is received from an external device, such as a host computer, through the communication section  202 . 
     Furthermore, the computer  200  functions as an image processing section by executing predetermined image processing programs. The image processing section performs processing for converting image data as an object, which is to be recorded, into data formats that can be handled by the ink jet recording apparatus  1 . Specifically, the image processing section performs, for example, processing for converting image data, which is represented by a RGB format, into dot arrangement data corresponding to the respective colors of cyan (C), magenta (M), yellow (Y), and black (K). The computer  200  drives the respective ink jet heads  110 C,  110 M,  110 Y, and  110 K on the basis of the generated dot arrangement data and records an image on the sheet P. 
     &lt;&lt;Procedure of Image Recording Processing Performed by Ink Jet Recording Apparatus&gt;&gt; 
     Next, a procedure of image recording processing, which is performed by the ink jet recording apparatus  1  of this embodiment, will be described. 
     The recording of an image is performed in the flow of (a) the feeding of a sheet, (b) the application of treatment liquid, (c) the drying of the treatment liquid, (d) recording, (e) the drying of ink, (f) the discharge of the sheet, and (g) collection. 
     In a case in which the image recording processing is started, sheets P are fed from the sheet feeding section  10  at regular intervals one by one. 
     First, treatment liquid is applied to the recording surface of the sheet P, which is fed from the sheet feeding section  10 , by treatment liquid applying section  20 . The treatment liquid applying section  20  applies the treatment liquid to the recording surface of the sheet P, which is transported, a roller. 
     Then, the sheet P to which the treatment liquid has been applied is subjected to drying processing by the treatment liquid drying section  30 . The treatment liquid drying section  30  blows hot air to the recording surface of the sheet P, which is transported, and performs processing for drying the sheet P. 
     Next, the sheet P, which has been subjected to drying processing, is subjected to recording processing by the image recording section  40 . The image recording section  40  jets ink droplets to the sheet P, which is transported, from the respective ink jet heads  110 C,  110 M,  110 Y, and  110 K and records a color image to the recording surface. 
     Then, the sheet P on which the image has been recorded is subjected to drying processing by the ink drying section  50 . The ink drying section  50  blows hot air to the recording surface of the sheet P, which is transported, and performs processing for drying the sheet P. 
     The sheet P, which has been subjected to drying processing, is transported up to the collection section  60 . Then, the sheets P are discharged to the collection section  60  and are collected in the form of a bundle. 
     &lt;&lt;Structure for Supporting Ink Jet Head by Mount&gt;&gt; 
     &lt;Structure of Ink Jet Head&gt; 
     First, the structure of the ink jet heads  110 C,  110 M,  110 Y, and  110 K will be described. Since the respective ink jet heads  110 C,  110 M,  110 Y, and  110 K have the same structure, the ink jet heads will be described while being denoted by reference numeral  110  in the following description except for a case in which the ink jet heads should be particularly distinguished from each other. 
       FIG. 5  is a perspective view showing the structure of the ink jet head. 
     The ink jet head  110  includes a plurality of head modules  120  that are joined in line. 
     The head module  120  is a so-called short ink jet head. Since the head modules  120  are joined to form one ink jet head, the length of the ink jet head can be easily increased. 
     Each of the head modules  120  includes a jetting portion  120 A at a tip portion thereof. The jetting portion  120 A has the shape of a flat parallelogram block. The tip face of the jetting portion  120 A forms a nozzle surface  120   a,  and a plurality of nozzles for jetting ink are arranged on the nozzle surface  120   a . The arrangement of the nozzles will be described below. 
     The plurality of head modules  120  are mounted on a first supporting frame  122  having the shape of a bar, and are integrated with each other. The first supporting frame  122  includes head module mounting portions (not shown) that are arranged at regular intervals in the longitudinal direction thereof. Each head module  120  is detachably mounted on the head module mounting portion. The respective head modules  120  are mounted on the head module mounting portions, so that the jetting portions  120 A are joined in line. Accordingly, since the nozzle surfaces  120   a  of the respective head modules  120  are joined in line, one long nozzle surface  112  is formed as a whole. 
       FIG. 6  is a plan view of the nozzle surface of the ink jet head. 
     As shown in  FIG. 6 , the nozzle surface  120   a  of each head module  120  includes a belt-like nozzle arrangement region  120   b  in the middle portion thereof. Nozzles N are arranged in the nozzle arrangement region  120   b.    
       FIG. 7  is an enlarged plan view of a part of the nozzle arrangement region. 
     As shown in  FIG. 7 , the nozzles N are arranged in the nozzle arrangement region  120   b  in the form of a matrix. In more detail, in a case in which a straight line parallel with the longitudinal direction of the ink jet head  110  is denoted by x and a straight line inclined with respect to the straight line x at an angle α is denoted by y, the nozzles N are arranged at a constant pitch along the straight line x and a constant pitch along the straight line y. Since the nozzles N are arranged in this way, the nozzles N can be densely arranged. A direction in which the nozzles N are substantially arranged in this case is the direction of the straight line x. That is, the nozzles N are substantially arranged in the longitudinal direction of the ink jet head  110 . 
     Ink, which is to be jetted from the nozzles N of the ink jet head  110  having the above-mentioned structure, is circulated and supplied to the ink jet head  110 . The supply of ink is performed by an ink supply section. The ink supply section is provided for each ink jet head. The ink supply section circulates and supplies ink to each of the head modules of the ink jet head. Accordingly, each of the head modules is provided with an ink supply port that is used to supply ink and an ink recovery port that is used to recover ink. 
     &lt;Ink Supply Section&gt; 
       FIG. 8  is a diagram showing the schematic configuration of the ink supply section. 
     As shown in  FIG. 8 , the ink supply section  130  includes an ink tank  132  that stores ink, a supply pump  134  that sends the ink to the ink jet heads  110  from the ink tank  132 , a recovery pump  136  that sends ink to the ink tank  132  from the ink jet heads  110 , a supply manifold  138  that makes the ink sent from the ink tank  132  branch to the respective head modules  120 , a recovery manifold  140  that collects the ink individually recovered from the respective head modules  120  together, a common supply pipe  142  that connects the ink tank  132  to the supply manifold  138 , a common recovery pipe  144  that connects the ink tank  132  to the recovery manifold  140 , individual supply pipes  146  that connect the supply manifold  138  to the respective head modules  120 , individual recovery pipes  148  that connect the recovery manifold  140  to the respective head modules  120 , a common supply damper  150  that is installed on the common supply pipe  142 , a common recovery damper  152  that is installed on the common recovery pipe  144 , individual supply dampers  154  that are installed on the respective individual supply pipes  146 , individual recovery dampers  156  that are installed on the respective individual recovery pipes  148 , individual supply valves  158  that are installed on the respective individual supply pipes  146 , and individual recovery valves  160  that are installed on the respective individual recovery pipes  148 . 
     The ink tank  132  stores ink that is jetted from the ink jet heads  110 . 
     The supply pump  134  is formed of, for example, a tube pump and sends the ink, which is stored in the ink tank  132 , to the ink jet heads  110  through the common supply pipe  142 . 
     The recovery pump  136  is formed of, for example, a tube pump and sends ink to the ink tank  132  from the ink jet heads  110  through the common recovery pipe  144 . 
     The supply manifold  138  connects the common supply pipe  142  to the individual supply pipes  146 . The supply manifold  138  makes the ink, which is sent from the common supply pipe  142 , branch and sends the ink to the respective individual supply pipes  146 . 
     The recovery manifold  140  connects the common recovery pipe  144  to the individual recovery pipes  148 . The recovery manifold  140  collects the ink, which is sent from the respective individual recovery pipes  148 , together and sends the ink to the common recovery pipe  144 . 
     The common supply pipe  142  connects the ink tank  132  to the supply manifold  138 . 
     The common recovery pipe  144  connects the ink tank  132  to the recovery manifold  140 . 
     The individual supply pipes  146  individually connect the supply manifold  138  to the respective head modules  120 . Each of the individual supply pipes  146  includes a supply-side connection port  146 A at the tip thereof. A flexible individual supply connection pipe  162  is connected to each supply-side connection port  146 A. Each of the individual supply pipes  146  is connected to an ink supply port  164 , which is provided in each head module  120 , through the individual supply connection pipe  162 . 
     The individual recovery pipes  148  individually connect the recovery manifold  140  to the respective head modules  120 . Each of the individual recovery pipes  148  includes a recovery-side connection port  148 A at the tip thereof. A flexible individual recovery connection pipe  166  is connected to each recovery-side connection port  148 A. Each of the individual recovery pipes  148  is connected to an ink recovery port  168 , which is provided in each head module  120 , through the individual recovery connection pipe  166 . 
     The common supply damper  150  is installed in the middle of the pipe line of the common supply pipe  142 . The common supply damper  150  absorbs the pressure variation of ink that flows in the common supply pipe  142 . The common supply damper  150  is installed for the main purpose of absorbing the pulsation of ink caused by the driving of the supply pump  134 . Accordingly, a large damper, which can absorb a large pressure variation, is used as the common supply damper  150 . 
     The common recovery damper  152  is installed in the middle of the pipe line of the common recovery pipe  144 . The common recovery damper  152  absorbs the pressure variation of ink that flows in the common recovery pipe  144 . The common recovery damper  152  is installed for the main purpose of absorbing the pulsation of ink caused by the driving of the recovery pump  136 . Accordingly, a large damper, which can absorb a large pressure variation, is used as the common recovery damper  152 . 
     The individual supply damper  154  is installed in the middle of the pipe line of each individual supply pipe  146 . The individual supply dampers  154  absorbs the pressure variation of ink that flows in each individual supply pipe  146 . Each of the individual supply dampers  154  is installed for the main purpose of absorbing the pressure variation of ink caused by the jetting of the ink. Accordingly, a damper, which is smaller than the common supply damper  150 , is used as the individual supply damper  154 . 
     The individual recovery damper  156  is installed in the middle of the pipe line of each individual recovery pipe  148 . The individual recovery damper  156  absorbs the pressure variation of ink that flows in each individual recovery pipe  148 . Each of the individual recovery dampers  156  is installed for the main purpose of absorbing the pressure variation of ink caused by the jetting of the ink. Accordingly, a damper, which is smaller than the common recovery damper  152 , is used as the individual recovery damper  156 . 
     The individual supply valve  158  is installed in the middle of the pipe line of each individual supply pipe  146 . The individual supply valve  158  is formed of, for example, a solenoid valve, and opens and closes the flow passage for ink that flows in each individual supply pipe  146 . 
     The individual recovery valve  160  is installed in the middle of the pipe line of each individual recovery pipe  148 . The individual recovery valve  160  is formed of, for example, a solenoid valve, and opens and closes the flow passage for ink that flows in each individual recovery pipe  148 . 
     The ink supply section  130  having the above-mentioned structure circulates and supplies ink to the ink jet heads  110  by driving the supply pump  134  and the recovery pump  136 . 
     One ink jet head  110  and the ink supply section  130 , which supplies ink to the ink jet head  110 , form one recording unit. Since the ink jet recording apparatus  1  of this embodiment uses inks having four colors of cyan, magenta, yellow, and black, the ink jet recording apparatus  1  is provided with four recording units. 
     A part of the ink supply section  130  is mounted on a second supporting frame  170  and is disposed in the vicinity of the ink jet head  110 . That is, the supply manifold  138 , the recovery manifold  140 , the individual supply pipes  146 , the individual recovery pipes  148 , the individual supply dampers  154 , the individual recovery dampers  156 , the individual supply valves  158 , and the individual recovery valves  160  are mounted on the second supporting frame  170  and are disposed in the vicinity of the ink jet head  110 . This will be described below. 
     &lt;Structure for Supporting Ink Jet Head&gt; 
     As described above, the respective ink jet heads  110 C,  110 M,  110 Y, and  110 K are mounted on the mount provided on the carriage. 
       FIG. 9  is a front view of the mount on which the ink jet heads are mounted. Further,  FIG. 10  is a cross-sectional view taken along line  10 - 10  of  FIG. 9 . 
     The mount  300  on which the ink jet heads  110 C,  110 M,  110 Y, and  110 K are mounted is provided on the carriage  310 . 
     [Carriage] 
     The carriage  310  has the shape of a rectangular frame. The carriage  310  is provided to be movable along a pair of guide rails  312 . The pair of guide rails  312  is provided in parallel with the rotation axis of the image recording drum  42 . The carriage  310  is slidably supported by the pair of guide rails  312  with a pair of sliders  314  interposed therebetween. 
     The carriage  310  is moved along the guide rails  312  by a feed screw mechanism  318  that is driven by a motor  316 . The feed screw mechanism  318  includes a feed screw  318 A and a nut  318 B that is fitted to the feed screw  318 A. The feed screw  318 A is disposed along the guide rails  312 , and is rotatably supported by bearings (not shown). The nut  318 B is connected to the carriage  310 . The motor  316  is connected to the feed screw  318 A, and rotates the feed screw  318 A in a normal direction and a reverse direction. 
     In a case in which the feed screw  318 A is rotated by the motor  316 , the nut  318 B is moved along the feed screw  318 A. As a result, the carriage  310  connected to the nut  318 B is moved along the guide rails  312 . 
     [Mount] 
     The mount  300  supports the first supporting frames  122  and the second supporting frames  170 . One first supporting frame  122  and one second supporting frame  170  making a pair form one supporting frame, and are provided for each recording unit. One mount  300  supports a plurality of supporting frames. That is, one mount  300  supports the plurality of first supporting frames  122  and second supporting frames  170 . 
     The mount  300  includes a pair of support plates  330 . The pair of support plates  330  is fixedly mounted on the carriage  310 . The support plates  330 , which are mounted on the carriage  310 , are disposed so as to face each other with the image recording drum  42  interposed therebetween. 
     A pair of first supporting frame bearers  332  and a pair of second supporting frame bearers  334  are provided on the surfaces of the pair of support plates  330  that face each other. The pair of first supporting frame bearers  332  and the pair of second supporting frame bearers  334  are provided for each recording unit, and the first supporting frame bearers  332  and the second supporting frame bearers  334  are arranged in the shape of an arc at regular intervals. 
     [First Support Frame Bearer] 
     The pair of first supporting frame bearers  332  is an example of a first supporting frame support, and supports the first supporting frame  122 . As described above, the first supporting frame  122  is a frame on which the head modules  120  are mounted. 
     As shown in  FIGS. 5 and 6 , first supporting frame-mounting portions  122 A are formed at both ends of the first supporting frame  122  in the longitudinal direction of the first supporting frame  122  so as to protrude. Each of the first supporting frame-mounting portions  122 A has the shape of a rectangular flat plate, and includes a first supporting frame-mounting surface  122   a  that is parallel with the nozzle surface  112 . Further, each of the first supporting frame-mounting portions  122 A includes a first supporting frame-mounting hole  122 B. The first supporting frame-mounting hole  122 B is orthogonal to the first supporting frame-mounting surface  122   a  and is provided so as to pass through the first supporting frame-mounting portion  122 A. 
     As shown in  FIG. 10 , each of the first supporting frame bearers  332  has the shape of a rectangular flat plate and is provided on the inside of the support plate  330  so as to protrude. Each of the first supporting frame bearers  332  includes a first supporting frame-receiving portion  332 A which has a recessed shape and to which the first supporting frame-mounting portion  122 A is fitted. The first supporting frame-receiving portion  332 A includes a first supporting frame-receiving surface  332   a  that is formed on the bottom of the first supporting frame-receiving portion  332 A and is flat. 
     Further, each of the first supporting frame bearers  332  includes a first supporting frame-fixing hole  332 B. The first supporting frame-fixing hole  332 B is orthogonal to the first supporting frame-receiving surface  332   a  and is provided so as to pass through the first supporting frame bearer  332 . 
     When the first supporting frame-mounting portions  122 A, which are provided at both ends of the first supporting frame  122 , are fitted to the first supporting frame-receiving portions  332 A of the first supporting frame bearers  332 , both ends of the first supporting frame  122  in the longitudinal direction are supported by the first supporting frame bearers  332 . Accordingly, the first supporting frame  122  is mounted on the mount  300 . The first supporting frame-mounting holes  122 B of the first supporting frame-mounting portions  122 A of the first supporting frame  122  mounted on the mount  300  are disposed coaxially with the first supporting frame-fixing holes  332 B of the first supporting frame bearers  332 . When first supporting frame-fixing pins  336  are inserted into the first supporting frame-mounting holes  122 B and the first supporting frame-fixing holes  332 B, the first supporting frame  122  is positioned on and fixed to the first supporting frame bearers  332 . 
     Incidentally, as described above, the respective ink jet heads  110 C,  110 M,  110 Y, and  110 K are arranged in the shape of an arc at regular intervals along the transport path PP of a sheet P. For this reason, the respective first supporting frame bearers  332  are arranged in the shape of an arc at regular intervals so as to correspond to the installation intervals of the ink jet heads  110 C,  110 M,  110 Y, and  110 K that are supported by the first supporting frame bearers  332 . Further, the respective first supporting frame bearers  332  are obliquely installed so as to correspond to the installation angles of the ink jet heads  110 C,  110 M,  110 Y, and  110 K that are supported by the first supporting frame bearers  332 . That is, the first supporting frame-receiving surfaces  332   a  are obliquely installed so as to correspond to the inclination angle of the nozzle surface of each ink jet head that is supported by the first supporting frame-receiving surfaces  332   a.  Accordingly, in a case in which the first supporting frames  122  are supported by the first supporting frame bearers  332 , the respective ink jet heads  110 C,  110 M,  110 Y, and  110 K supported by the first supporting frames  122  are arranged in the shape of an arc at regular intervals along the transport path PP of a sheet P. 
     [Second Supporting Frame Bearer] 
     The pair of second supporting frame bearers  334  is an example of a second supporting frame support, and supports the second supporting frame  170 . As described above, the second supporting frame  170  supports a part of the ink supply section  130 . Specifically, the second supporting frame  170  supports the supply manifold  138 , the recovery manifold  140 , the individual supply pipes  146 , the individual recovery pipes  148 , the individual supply dampers  154 , the individual recovery dampers  156 , the individual supply valves  158 , and the individual recovery valves  160  (see  FIG. 8 ). In addition, a drive board for driving the ink jet head  110 , sensors, and the like are mounted on the second supporting frame  170 . These are members that should be preferably disposed in the vicinity of the ink jet head  110 . 
     In  FIG. 5 , reference numeral  124  denotes electrical wires that extend from the respective head modules  120 . The electrical wires  124  are connected to the drive board that is supported by the second supporting frame  170 . 
     The second supporting frame  170  includes a long second supporting frame body  170 X. The respective members of the ink supply section  130  are mounted on the second supporting frame body  170 X. 
     The second supporting frame body  170 X includes second supporting frame-mounting portions  170 A at both ends thereof in the longitudinal direction thereof. Each of the second supporting frame-mounting portions  170 A has the shape of a rectangular flat plate, and includes a second supporting frame-mounting surface  170   a  that is flat. Further, each of the second supporting frame-mounting portions  170 A includes a second supporting frame-mounting hole  170 B. The second supporting frame-mounting hole  170 B is orthogonal to the second supporting frame-mounting surface  170   a  and is provided so as to pass through the second supporting frame-mounting portion  170 A. 
     As shown in  FIG. 10 , each of the second supporting frame bearers  334  has the shape of a rectangular flat plate and is provided on the inside of the support plate  330  so as to protrude. Each of the second supporting frame bearers  334  includes a second supporting frame-receiving portion  334 A which has a recessed shape and to which the second supporting frame-mounting portion  170 A is fitted. The second supporting frame-receiving portion  334 A includes a second supporting frame-receiving surface  334   a  that is formed on the bottom of the second supporting frame-receiving portion  334 A and is flat. 
     Further, each of the second supporting frame bearers  334  includes a second supporting frame-fixing hole  334 B. The second supporting frame-fixing hole  334 B is orthogonal to the second supporting frame-receiving surface  334   a  and is provided so as to pass through the second supporting frame bearer  334 . 
     When the second supporting frame-mounting portions  170 A, which are provided at both ends of the second supporting frame  170 , are fitted to the second supporting frame-receiving portion  334 A of the second supporting frame bearers  334 , both ends of the second supporting frame  170  in the longitudinal direction are supported by the second supporting frame bearers  334 . Accordingly, the second supporting frame  170  is mounted on the mount  300 . The second supporting frame-mounting hole  170 B of the second supporting frame-mounting portions  170 A of the second supporting frame  170  mounted on the mount  300  are disposed coaxially with the second supporting frame-fixing holes  334 B of the second supporting frame bearers  334 . When second supporting frame-fixing pins  338  are inserted into the second supporting frame-mounting holes  170 B and the second supporting frame-fixing holes  334 B, the second supporting frame  170  is positioned on and fixed to the second supporting frame bearers  334 . 
     Here, the respective second supporting frame bearers  334  are arranged in the shape of an arc at the same intervals as the intervals of the first supporting frame bearers  332 . Specifically, in a case in which a straight line passing through the center O of rotation of the image recording drum  42  and the center of the first supporting frame-receiving surface  332   a  of the first supporting frame bearer  332  is denoted by L 1 , the second supporting frame bearers  334  are arranged on the straight line L 1 . Further, the second supporting frame bearers  334  are arranged so that the second supporting frame-receiving surface  334   a  of the second supporting frame bearer  334  is orthogonal to the straight line L 1  and the straight line L 1  passes through the center of the second supporting frame-receiving surface  334   a.    
     Accordingly, in a case in which the second supporting frame  170  is supported by the second supporting frame bearers  334 , the first supporting frames  122  and the second supporting frames  170  are disposed in series on the same straight line. 
     The first supporting frame-receiving surfaces  332   a  of the first supporting frame bearers  332  are provided to be orthogonal to the straight line L 1 . Accordingly, in a case in which the first supporting frame  122  is supported by the first supporting frame bearers  332 , the nozzle surface  112  of the ink jet head  110  supported by the first supporting frame  122  is also disposed to be orthogonal to the straight line L 1 . The direction of the straight line L 1  is the same direction as the ink jetting direction of the ink jet head  110 . Accordingly, in a case in which the first supporting frame  122  is supported by the first supporting frame bearers  332  and the second supporting frame  170  is supported by the second supporting frame bearers  334 , the first supporting frames  122  and the second supporting frames  170  are disposed in series in the ink jetting direction of the ink jet head  110 . 
     [Connection Mechanism] 
     As shown in  FIG. 10 , connecting arms  180 , which are to be connected to the first supporting frame  122 , are provided at both end portions of the second supporting frame  170  in the longitudinal direction of the second supporting frame  170 . The connecting arms  180  are an example of a connecting member. Each of the connecting arms  180  is connected to the first supporting frame  122  by a pin  182 . 
     [Bending Correction Mechanism] 
     As shown in  FIG. 10 , the second supporting frame  170  is provided with a bending correction mechanism  340  that corrects the bending of the first supporting frame  122 . The bending correction mechanism  340  is an example of bending correction unit. 
     As described above, the first supporting frame  122  is mounted on the mount  300  while both end portions of the first supporting frame  122  in the longitudinal direction are supported by the first supporting frame bearers  332 . In a case in which the long first supporting frame  122  is supported in this way, the middle portion of the first supporting frame  122  is bent by its own weight. For this reason, warpage occurs. The bending correction mechanism  340  applies a pressing force to the first supporting frame  122  to correct the bending of the first supporting frame  122 . 
       FIG. 11  is a front view showing the schematic structure of the bending correction mechanism. Further,  FIG. 12  is an enlarged view of the bending correction mechanism. 
     The bending correction mechanism  340  includes a pressing spring  342 , and applies a pressing force, which is generated by the pressing spring  342 , to the first supporting frame  122 . 
     The pressing spring  342  is provided on a pressing spring support  344  that is provided on the second supporting frame  170 . The pressing spring support  344  has the shape of a long flat plate, and a base end portion of the pressing spring support  344  is fixed to the second supporting frame  170 . The pressing spring  342  is provided at a tip portion of the pressing spring support  344 . 
     The pressing spring  342  includes a hemispherical contactor  346  at the tip portion thereof. The bending correction mechanism  340  makes the contactor  346  be in contact with the first supporting frame  122  and applies a pressing force, which is generated by the pressing spring  342 , to the first supporting frame  122 . 
     Here, a position at which the contactor  346  is in contact with the first supporting frame  122  is set to a position at which bending can be corrected. In a case in which both ends of the first supporting frame  122  in the longitudinal direction are supported, a position at which the bending of the first supporting frame  122  is largest is the middle portion of the first supporting frame  122  in the longitudinal direction. Accordingly, in a case in which only one portion of the first supporting frame  122  is to be pressed, it is preferable that the contactor  346  is in contact with the middle portion of the first supporting frame  122  in the longitudinal direction or the vicinity thereof. 
     Further, a direction in which a pressing force is applied is also set to a direction in which bending can be corrected. Specifically, a direction in which a pressing force is applied is set to a direction in which bending is cancelled. In this embodiment, as shown in  FIG. 12 , a pressing force in a direction D 3  opposite to an inclination direction D 2  of the ink jet head  110  is applied for the main purpose of correcting bending caused by the oblique installation of the ink jet head  110 . 
     In a case in which each of the ink jet heads  110 C,  110 M,  110 Y, and  110 K is obliquely installed as in the ink jet recording apparatus  1  of this embodiment, the bending of the first supporting frame  122  varies for every ink jet head  110 C,  110 M,  110 Y, and  110 K. Accordingly, the directions of the pressing forces, which are applied by the pressing springs  342 , are individually set for the first supporting frames  122 . 
     Further, the magnitude of a pressing force to be applied is also set according to the degree of the bending of each first supporting frame  122 . Since the bending of the first supporting frame  122  varies for every first supporting frame  122  as described above, the magnitude of a force required for correction also varies. Accordingly, the magnitudes of the pressing forces, which are applied by the pressing springs  342 , are also individually set for every first supporting frame  122 . 
     &lt;Action of Structure for Supporting Ink Jet Head&gt; 
     According to the structure for supporting the ink jet head  110  that is adapted as described above, the ink jet head  110  is supported by the first supporting frame  122  and is installed on the mount  300  through the first supporting frame  122 . 
     The mount  300  includes the first supporting frame bearers  332  as the first supporting frame support, supports both ends of the first supporting frame  122  in the longitudinal direction by the first supporting frame bearers  332 , and supports the ink jet head  110  with a predetermined posture at a predetermined position. 
     Incidentally, in a case in which both ends of the first supporting frame  122  are supported in this way and the ink jet head  110  is mounted on the mount  300 , there is a concern that the first supporting frame  122  may be bent by its own weight. 
     However, since the ink jet recording apparatus  1  of this embodiment is provided with the bending correction mechanism  340  that corrects the bending of the first supporting frame  122 , the ink jet recording apparatus  1  can effectively prevent the first supporting frame  122  from being bent. 
     The bending correction mechanism  340  is provided on the second supporting frame  170 , and presses the first supporting frame  122  by the pressing spring  342  to correct the bending of the first supporting frame  122 . Accordingly, since the bending of the first supporting frame  122  can be prevented even in a case in which both ends of the first supporting frame  122  in the longitudinal direction are supported, a high-quality image can be recorded. 
     Further, since the bending correction mechanism  340  is provided on the second supporting frame  170 , the structure of the mount can be simplified. Accordingly, since the installation interval between the respective ink jet heads can be reduced, a part on which the ink jet heads are to be installed can be made compact. 
     Furthermore, since the first supporting frame  122  that is a frame supporting the ink jet head  110  and the second supporting frame  170  that is a frame supporting the ink supply section  130  and the like are separated from each other, the first supporting frame  122  that is a frame supporting the ink jet head  110  can be reduced in weight. Accordingly, it is possible to effectively prevent the first supporting frame  122 , which is a frame supporting the ink jet head  110 , from being bent. 
     &lt;Method of Setting Pressing Force&gt; 
     As described above, the magnitudes and directions of the pressing forces, which are to be applied to the first supporting frame  122 , are set according to the bending of the first supporting frame  122 . For example, a predetermined test chart is printed to measure the bending of the first supporting frame  122 . The magnitudes and directions of pressing forces, which are applied to correct bending, are adjusted on the basis of the results of measurement. 
     The adjustment of every ink jet head can also be performed independently of each other according to predetermined reference, but the adjustment of the ink jet heads can also be performed so that the distribution of landing positions is the same between the respective ink jet heads. For example, one color as a reference is selected, and the bending of the first supporting frame  122  of each ink jet head  110  is corrected so that the distribution of landing positions of each ink jet head becomes the same as the distribution of landing positions of the ink jet head corresponding to the selected color. For example, in a case in which the ink jet head corresponding to cyan is selected as a reference, the bending of the first supporting frame  122  of each of the ink jet heads corresponding to magenta, yellow, and black is corrected so that the distribution of landing positions of each of the ink jet heads corresponding to magenta, yellow, and black becomes the same as the distribution of landing positions of the ink jet head corresponding to cyan. 
     Modification Example 
     The bending correction mechanism  340  has been adapted to press one portion of the first supporting frame  122  in the above-mentioned embodiment, but can also be adapted to press a plurality of portions of the first supporting frame  122 . 
       FIG. 13  is a diagram showing the schematic structure of the bending correction mechanism in a case in which a plurality of portions of the first supporting frame are pressed to correct bending. 
     In an example shown in  FIG. 13 , the bending correction mechanism  340  includes a plurality of pressing springs  342  and is adapted to press a plurality of portions of the first supporting frame  122  to correct the bending of the first supporting frame  122 . 
     The respective pressing springs  342  are arranged on the same straight line in the longitudinal direction of the first supporting frame  122 , and are arranged so as to be symmetrical with respect to the middle of the first supporting frame  122  in the longitudinal direction. 
     The respective pressing springs  342  press the first supporting frame  122  in the same direction through contactors (not shown). That is, the respective pressing springs  342  press the first supporting frame  122  in a direction opposite to the inclination direction of the ink jet head  110  that is supported by the first supporting frame  122 . 
     The pressing forces of the respective pressing springs  342  are individually set. In this case, the pressing force of the pressing spring  342 , which is disposed in the middle of the bending correction mechanism  340  in the longitudinal direction, is set to be largest and the pressing forces of the pressing springs  342  are set to be reduced toward both ends of the bending correction mechanism  340 . 
     Second Embodiment 
       FIG. 14  is a front view showing a second embodiment of the bending correction mechanism. 
     The force of the pressing spring  342  has been directly applied to the first supporting frame  122  in the above-mentioned embodiment, but the force of the pressing spring  342  is applied to the first supporting frame  122  by using the principle of the lever in a bending correction mechanism  340 A of this embodiment. 
     As shown in  FIG. 14 , the bending correction mechanism  340 A includes a lever  348 . The lever  348  is supported by a lever support  348 A, which is provided on the second supporting frame  170 , so as to freely oscillate. 
     The lever support  348 A includes an oscillating shaft  348   a  that is set in parallel with the rotation axis of the image recording drum  42 . The lever  348  is supported so as to freely oscillate about the oscillating shaft  348   a  as a fulcrum. 
     A pressing spring  342  is provided at a base end portion of the lever  348 . One end of the pressing spring  342  is fixed to the second supporting frame  170  and the other end thereof is fixed to the base end portion of the lever  348 , so that the pressing spring  342  applies a pressing force to the lever  348 . This pressing force is a force that rotates the lever  348  counterclockwise in  FIG. 14 . 
     A contactor  346  is provided at the tip of the lever  348 . The contactor  346  is in pressure contact with the first supporting frame  122 , so that a pressing force is applied to the first supporting frame  122 . 
     In this way, a pressing force can be applied to the first supporting frame  122  by using the lever. Since the principle of the lever is used, the force of the pressing spring  342  can be efficiently used to correct the bending of the first supporting frame  122 . 
     Third Embodiment 
       FIG. 15  is a front view showing a third embodiment of the bending correction mechanism. 
     As shown in  FIG. 15 , a bending correction mechanism  350  of this embodiment applies a tensile force to the first supporting frame  122  to correct the bending of the first supporting frame  122 . 
     The bending correction mechanism  350  includes a tension spring  352 , and applies a tensile force, which is generated by the tension spring  352 , to the first supporting frame  122 . 
     The tension spring  352  is provided on a tension spring support  354  that is provided on the second supporting frame  170 . The tension spring support  354  has the shape of a long flat plate, and a base end portion of the tension spring support  354  is fixed to the second supporting frame  170 . The tension spring  352  is provided at a tip portion of the tension spring support  354 . One end of the tension spring  352  is fixed to the tension spring support  354  and the other end thereof is connected to the first supporting frame  122 , so that the tension spring  352  applies a tensile force to the first supporting frame  122 . 
     Here, a position to which a tensile force generated by the tension spring  352  is applied is set to a position at which bending can be corrected. In a case in which a tensile force is applied to only one portion of the first supporting frame  122  as in this example, it is preferable that tensile force is applied to the middle portion of the first supporting frame  122  in the longitudinal direction or the vicinity thereof. 
     Further, a direction in which a tensile force is applied is also set to a direction in which bending can be corrected. Specifically, a direction in which a tensile force is applied is also set to a direction in which bending is cancelled. In this embodiment, a tensile force in a direction D 3  opposite to an inclination direction D 2  of the ink jet head  110  is applied for the main purpose of correcting bending caused by the oblique installation of the ink jet head  110 . Directions in which tensile forces are to be applied are individually set for the first supporting frames  122 . 
     Further, the magnitude of a tensile force is also set according to the degree of the bending of each first supporting frame  122 . Since the bending of the first supporting frame  122  varies for every first supporting frame  122  as described above, the magnitude of a force required for correction also varies. Accordingly, the magnitudes of the tensile forces, which are applied by the tension springs  352 , are also individually set for every first supporting frame  122 . 
     A tensile force is applied to the first supporting frame  122  in this way, so that the bending of the first supporting frame  122  can also be corrected. Since the bending correction mechanism  350  is provided on the second supporting frame  170  even in this case, the structure of the mount can be simplified. 
     One portion has been adapted to be pulled in the above-mentioned embodiments, but a plurality of portions can also be adapted to be pulled. 
     Further, a tensile force can also be adapted to be applied by using the principle of the lever as in the above-mentioned second embodiment. 
     Fourth Embodiment 
     A pressing force or a tensile force has been adapted to be applied to the first supporting frame from the bending correction mechanism provided on the same supporting frame in the above-mentioned embodiments, but a pressing force or a tensile force can also be adapted to be applied to the first supporting frame from a bending correction mechanism provided on the adjacent supporting frame. 
       FIG. 16  is a front view showing a schematic structure in a case in which a tensile force is applied to the first supporting frame from a bending correction mechanism provided on adjacent supporting frame to correct the bending of a first supporting frame. 
     In  FIG. 16 , reference numeral  122 C denotes a first supporting frame of an ink jet head  110 C corresponding to cyan and reference numeral  122 M denotes a first supporting frame of an ink jet head  110 M corresponding to magenta. Further, reference numeral  122 Y denotes a first supporting frame of an ink jet head  110 Y corresponding to yellow and reference numeral  122 K denotes a first supporting frame of an ink jet head  110 K corresponding to black. 
     Furthermore, reference numeral  170 C denotes a second supporting frame of the ink jet head  110 C corresponding to cyan and reference numeral  170 M denotes a second supporting frame of the ink jet head  110 M corresponding to magenta. Moreover, reference numeral  170 Y denotes a second supporting frame of the ink jet head  110 Y corresponding to yellow and reference numeral  170 K denotes a second supporting frame of the ink jet head  110 K corresponding to black. 
     The first supporting frame  122 C and the second supporting frame  170 C of the ink jet head  110 C corresponding to cyan form the supporting frame of the ink jet head  110 C corresponding to cyan, and the first supporting frame  122 M and the second supporting frame  170 M of the ink jet head  110 M corresponding to magenta form the supporting frame of the ink jet head  110 M corresponding to magenta. Further, the first supporting frame  122 Y and the second supporting frame  170 Y of the ink jet head  110 Y corresponding to yellow form the supporting frame of the ink jet head  110 Y corresponding to yellow, and the first supporting frame  122 K and the second supporting frame  170 K of the ink jet head  110 K corresponding to black form the supporting frame of the ink jet head  110 K corresponding to black. 
     Furthermore, in  FIG. 16 , reference numeral  350 C denotes a bending correction mechanism that corrects the bending of the first supporting frame  122 C corresponding to cyan and reference numeral  350 M denotes a bending correction mechanism that corrects the bending of the first supporting frame  122 M corresponding to magenta. Moreover, reference numeral  350 Y denotes a bending correction mechanism that corrects the bending of the first supporting frame  122 Y corresponding to yellow and reference numeral  350 K denotes a bending correction mechanism that corrects the bending of the first supporting frame  122 K corresponding to black. 
     Further, in  FIG. 16 , reference numeral  352 C denotes a tension spring provided on the bending correction mechanism  350 C corresponding to cyan and reference numeral  352 M denotes a tension spring provided on the bending correction mechanism  350 M corresponding to magenta. Furthermore, reference numeral  352 Y denotes a tension spring provided on the bending correction mechanism  350 Y corresponding to yellow and reference numeral  352 K denotes a tension spring provided on the bending correction mechanism  350 K corresponding to black. 
     As shown in  FIG. 16 , the bending correction mechanism  350 C, which corrects the bending of the first supporting frame  122 C corresponding to cyan, is provided on the second supporting frame  170 M corresponding to magenta and the bending correction mechanism  350 M, which corrects the bending of the first supporting frame  122 M corresponding to magenta, is provided on the second supporting frame  170 Y corresponding to yellow. Further, the bending correction mechanism  350 Y, which corrects the bending of the first supporting frame  122 Y corresponding to yellow, is provided on the second supporting frame  170 M corresponding to magenta and the bending correction mechanism  350 K, which corrects the bending of the first supporting frame  122 K corresponding to black, is provided on the second supporting frame  170 Y corresponding to yellow. 
     In more detail, one end of the tension spring  352 C of the bending correction mechanism  350 C corresponding to cyan is fixed to the second supporting frame  170 M corresponding to magenta and the other thereof is connected to the first supporting frame  122 C corresponding to cyan, so that a tensile force is applied to the first supporting frame  122 C corresponding to cyan. 
     Furthermore, one end of the tension spring  352 M of the bending correction mechanism  350 M corresponding to magenta is fixed to the second supporting frame  170 Y corresponding to yellow and the other thereof is connected to the first supporting frame  122 M corresponding to magenta, so that a tensile force is applied to the first supporting frame  122 M corresponding to magenta. 
     Moreover, one end of the tension spring  352 Y of the bending correction mechanism  350 Y corresponding to yellow is fixed to the second supporting frame  170 M corresponding to magenta and the other thereof is connected to the first supporting frame  122 Y corresponding to yellow, so that a tensile force is applied to the first supporting frame  122 Y corresponding to yellow. 
     Further, one end of the tension spring  352 K of the bending correction mechanism  350 K corresponding to black is fixed to the second supporting frame  170 Y corresponding to yellow and the other thereof is connected to the first supporting frame  122 K corresponding to black, so that a tensile force is applied to the first supporting frame  122 K corresponding to black. 
     In this way, a tensile force can also be adapted to be applied to the first supporting frame from the bending correction mechanism provided on the adjacent supporting frame. 
     A case in which a tensile force is applied to the first supporting frame from the bending correction mechanism provided on the adjacent supporting frame has been described in this example by way of example, but a pressing force can also be adapted to be applied to the first supporting frame from the bending correction mechanism provided on the adjacent supporting frame. 
       FIG. 17  is a diagram showing a schematic structure in a case in which a pressing force is applied to the first supporting frame from the bending correction mechanism provided on the adjacent supporting frame. 
     In an example shown in  FIG. 17 , the bending correction mechanism  350 M, which corrects the bending of the first supporting frame  122 M corresponding to magenta, is provided on the second supporting frame  170 C corresponding to cyan and a pressing force is adapted to be applied to the first supporting frame  122 M, which corresponds to magenta, by the bending correction mechanism  350 M provided on the second supporting frame  170 C corresponding to cyan. Further, the bending correction mechanism  350 Y, which corrects the bending of the first supporting frame  122 Y corresponding to yellow, is provided on the second supporting frame  170 K corresponding to black and a pressing force is adapted to be applied to the first supporting frame  122 Y, which corresponds to yellow, by the bending correction mechanism  350 Y provided on the second supporting frame  170 K corresponding to black. 
     The bending correction mechanism that corrects the bending of the first supporting frame  122 C corresponding to cyan and the bending correction mechanism that corrects the bending of the first supporting frame  122 K corresponding to black are not shown in the example shown in  FIG. 17 . However, for example, the bending correction mechanism, which corrects the bending of the first supporting frame  122 C corresponding to cyan, may be provided on the second supporting frame corresponding to cyan and may be provided on the second supporting frame corresponding to magenta. Likewise, the bending correction mechanism, which corrects the bending of the first supporting frame  122 K corresponding to black, may be provided on the second supporting frame  170 K corresponding to black, and may be provided on the second supporting frame  170 Y corresponding to yellow. In this case, a tensile force may be adapted to be applied to correct bending, and a pressing force may be adapted to be applied to correct bending. That is, a portion at which the bending correction mechanism is installed and a force to be applied can be appropriately combined with each other when used. It is preferable that a portion at which the bending correction mechanism is installed and a force to be applied are selected in consideration of the installation space of the bending correction mechanism and the like. 
     Fifth Embodiment 
       FIG. 18  is a front view showing a fifth embodiment of the bending correction mechanism. 
     As shown in  FIG. 18 , a bending correction mechanism  360  of this embodiment applies tensile forces to the first supporting frame  122  from both sides of a first supporting frame  122  in a lateral direction of the first supporting frame  122  to correct the bending of the first supporting frame  122 . The lateral direction of the first supporting frame  122  is a direction orthogonal to the longitudinal direction of the first supporting frame  122 . 
     The bending correction mechanism  360  includes a first spring  362 A that pulls one end of the first supporting frame  122  in the lateral direction and a second spring  362 B that pulls the other end of the first supporting frame  122  in the lateral direction. The first spring  362 A and the second spring  362 B are disposed so as to be symmetrical with each other with the first supporting frame  122  interposed therebetween. 
     A second supporting frame  170  is provided with a first spring support  364 A to which a base end portion of the first spring  362 A is fixed and a second spring support  364 B to which a base end portion of the second spring  362 B is fixed. The first spring support  364 A and the second spring support  364 B are disposed in the middle of the second supporting frame  170  in a longitudinal direction, and are disposed so as to be symmetrical with each other with the second supporting frame  170  interposed therebetween in the lateral direction. 
     The first supporting frame  122  is provided with a first spring-connecting portion  366 A to which a tip of the first spring  362 A is connected and a second spring-connecting portion  366 B to which a tip of the second spring  362 B is connected. The first spring-connecting portion  366 A and the second spring-connecting portion  366 B are disposed in the middle of the first supporting frame  122  in a longitudinal direction, and are disposed so as to be symmetrical with each other with the first supporting frame  122  interposed therebetween in the lateral direction. 
     According to the bending correction mechanism  360  of this embodiment having the above-mentioned structure, the first supporting frame  122  is pulled from both sides thereof in the lateral direction by the first spring  362 A and the second spring  362 B, so that the bending of the first supporting frame  122  is corrected. The pulling direction is a direction opposite to the ink jetting direction. 
     Since tensile forces are applied in two directions in this way to correct bending, bending can be more appropriately corrected. That is, since the first supporting frame  122  is pulled in two directions, fine adjustment can be performed in regard to the correction of bending. Accordingly, the bending of each first supporting frame  122  can be more appropriately corrected. The fine adjustment is performed by the individual adjustment of the spring constant of the first spring  362 A and the spring constant of the second spring  362 B. 
     Only the middle of the first supporting frame  122  in the longitudinal direction has been adapted to be pulled in the above-mentioned embodiments, but a plurality of portions of the first supporting frame  122  can also be adapted to be pulled. 
     Further, the first supporting frame  122  has been adapted to be pulled in the direction opposite to the ink jetting direction in the above-mentioned embodiments, but can also be adapted to be pulled at an angle. 
     Other Embodiments 
     &lt;Ink Jet Head&gt; 
     A case in which the ink jet head including the plurality of joined head modules is supported has been described in the above-mentioned embodiments by way of example. However, the invention can also be applied to a case in which an ink jet head formed as a single body is supported, likewise. 
     Further, a case in which a plurality of head modules are arranged in line on the same straight line to form one ink jet head has been described in the above-mentioned embodiments, but the invention can also be applied to a case in which a plurality of head modules are arranged in a zigzag pattern to form one ink jet head. 
     &lt;Supporting Frame&gt; 
     A part of the ink supply section and the drive board have been mounted on the second supporting frame in the above-mentioned embodiments, but members to be mounted on the second supporting frame are not limited thereto. Members, which need to be disposed in the vicinity of the ink jet head, can be mounted on the second supporting frame. Accordingly, the support of the ink jet head can be reduced in weight. 
     Both ends of the second supporting frame in the longitudinal direction have been adapted to be supported by the mount in the above-mentioned embodiments, but the support aspect of the second supporting frame is not limited thereto. Three or more portions of the second supporting frame can also be adapted to be supported. 
     Further, the first and second supporting frames have been connected to each other by the connecting member in the above-mentioned embodiments, but can also be adapted to be separated from each other. When the first and second supporting frames are connected to each other by the connecting member and are integrated with each other as in the above-mentioned embodiments, the first and second supporting frames can be easily attached to or/and detached from the mount. 
     Furthermore, in a case in which the first and second supporting frames are to be connected to each other by the connecting member, the first and second supporting frames may be fixedly connected to each other by bolts, welding, or the like and may be movably connected to each other by pins or the like. Moreover, a lock mechanism may be provided in a case in which the first and second supporting frames are to be movably connected to each other. 
     Further, the materials of the first and second supporting frames, which form the supporting frame, are not particularly limited, and it is preferable that a material having a high stiffness is used as the materials of the first and second supporting frames. Particularly, since the deformation of the first supporting frame directly affects the quality of an image, it is preferable that a material having a high stiffness and a low coefficient of thermal expansion is used as the material of the first supporting frame. For example, Invar can be used as the material of the first supporting frame. On the other hand, since an influence of the second supporting frame on the quality of an image is small, the second supporting frame can be made of metal, such as aluminum or stainless. 
     &lt;First Supporting Frame Support&gt; 
     The first supporting frame-fixing pins  336  have been inserted into the first supporting frame-mounting holes  122 B of the first supporting frame  122  and the first supporting frame-fixing holes  332 B of the first supporting frame bearers  332  in the above-mentioned embodiments, so that the first supporting frame  122  has been fixed to the first supporting frame bearers  332 . However, a method of fixing the first supporting frame to the mount is not limited thereto. Both ends of the first supporting frame in the longitudinal direction have only to be supported. 
     Furthermore, the first supporting frames have been adapted to be fixed to the mount at fixed positions in the above-mentioned embodiments, but a mechanism for moving the supported first supporting frame up and down may be provided. That is, lifting means for moving the first supporting frame support up and down may be provided on the mount. 
     &lt;Layout of Ink Jet Heads&gt; 
     The ink jet heads have been arranged in the shape of an arc in the above-mentioned embodiments, but the layout of the ink jet heads is determined depending on means for transporting media. For example, in a case in which media are transported in the form of a straight line, the ink jet heads are arranged in the form of a straight line. 
     Further, a case in which the ink jet heads for jetting inks having different colors are mounted on one mount has been described in the above-mentioned embodiments by way of example, but the invention can also be applied to a case in which a plurality of ink jet heads for jetting ink having the same color are mounted on one mount. 
     &lt;Carriage&gt; 
     The mount has been mounted on the carriage in the above-mentioned embodiments, but the mount can be fixedly installed in the apparatus. 
     &lt;Application to Other Apparatuses&gt; 
     A case in which the invention is applied to an ink jet recording apparatus for recording a color image on a general-purpose printing sheet has been described in the above-mentioned embodiments by way of example, but the application of the invention is not limited thereto. In addition to this, for example, the invention can be widely applied to apparatuses for obtaining various shapes or patterns with a liquid functional material, such as a wiring drawing apparatus for drawing a wiring pattern of an electronic circuit by an ink jet method, an apparatus for manufacturing various devices, a resist printing apparatus using resin liquid as functional liquid to be jetted, an apparatus for manufacturing a color filter, and a microstructure forming apparatus for forming a microstructure with a material for material position. 
     EXPLANATION OF REFERENCES 
     
         
           1 : ink jet recording apparatus 
           10 : sheet feeding section 
           12 : sheet feeding device 
           12 A: sheet feed tray 
           14 : feeder board 
           16 : sheet feed drum 
           20 : treatment liquid applying section 
           22 : treatment liquid applying drum 
           23 : gripper 
           24 : treatment liquid applying device 
           30 : treatment liquid drying section 
           32 : treatment liquid drying drum 
           33 : gripper 
           34 : hot air blower 
           40 : image recording section 
           42 : image recording drum 
           43 : gripper 
           48 : scanner 
           50 : ink drying section 
           52 : chain delivery 
           52 A: chain 
           52 B: gripper 
           54 : sheet guide 
           56 : hot air blowing unit 
           60 : collection section 
           62 : collection device 
           62 A: collection tray 
           70 : maintenance section 
           72 : cap device 
           72 C,  72 M,  72 Y,  72 K: cap 
           74 : cleaning device 
           74 C,  74 M,  74 Y,  74 K: cleaner 
           100 : head unit 
           110 : ink jet head 
           110 C: ink jet head corresponding to cyan 
           110 M: ink jet head corresponding to magenta 
           110 Y: ink jet head corresponding to yellow 
           110 K: ink jet head corresponding to black 
           112 : nozzle surface 
           112 C,  112 M,  112 Y,  112 K: nozzle surface 
           120 : head module 
           120 A: jetting portion of head module 
           120   a : nozzle surface of head module 
           120   b : nozzle arrangement region 
           122 : first supporting frame 
           122 A: first supporting frame-mounting portion 
           122 B: first supporting frame-mounting hole 
           122 C: first supporting frame of ink jet head corresponding to cyan 
           122 M: first supporting frame of ink jet head corresponding to magenta 
           122 Y: first supporting frame of ink jet head corresponding to yellow 
           122 K: first supporting frame of ink jet head corresponding to black 
           122   a : first supporting frame-mounting surface 
           124 : electrical wire 
           130 : ink supply section 
           132 : ink tank 
           134 : supply pump 
           136 : recovery pump 
           138 : supply manifold 
           140 : recovery manifold 
           142 : common supply pipe 
           144 : common recovery pipe 
           146 : individual supply pipe 
           146 A: supply-side connection port 
           148 : individual recovery pipe 
           148 A: recovery-side connection port 
           150 : common supply damper 
           152 : common recovery damper 
           154 : individual supply damper 
           156 : individual recovery damper 
           158 : individual supply valve 
           160 : individual recovery valve 
           162 : individual supply connection pipe 
           164 : ink supply port 
           166 : individual recovery connection pipe 
           168 : ink recovery port 
           170 : second supporting frame 
           170 A: second supporting frame-mounting portion 
           170 B: second supporting frame-mounting hole 
           170 X: second supporting frame body 
           170 C: second supporting frame of ink jet head corresponding to cyan 
           170 M: second supporting frame of ink jet head corresponding to magenta 
           170 Y: second supporting frame of ink jet head corresponding to yellow 
           170 K: second supporting frame of ink jet head corresponding to black 
           170   a : second supporting frame-mounting surface 
           180 : connecting arm 
           182 : pin 
           200 : computer 
           202 : communication section 
           204 : operation section 
           206 : display section 
           208 : storage section 
           300 : mount 
           310 : carriage 
           312 : guide rail 
           314 : slider 
           316 : motor 
           318 : feed screw mechanism 
           318 A: feed screw 
           318 B: nut 
           330 : support plate 
           332 : first supporting frame bearer 
           332 A: first supporting frame-receiving portion 
           332 B: first supporting frame-fixing hole 
           332   a : first supporting frame-receiving surface 
           334 : second supporting frame bearer 
           334 A: second supporting frame-receiving portion 
           334 B: second supporting frame-fixing hole 
           334   a : second supporting frame-receiving surface 
           336 : first supporting frame-fixing pin 
           338 : second supporting frame-fixing pin 
           340 : bending correction mechanism 
           340 A: bending correction mechanism 
           342 : pressing spring 
           344 : pressing spring support 
           346 : contactor 
           348 : lever 
           348 A: lever support 
           348   a : oscillating shaft 
           350 : bending correction mechanism 
           350 C: bending correction mechanism corresponding to cyan 
           350 M: bending correction mechanism corresponding to magenta 
           350 Y: bending correction mechanism corresponding to yellow 
           350 K: bending correction mechanism corresponding to black 
           352 : tension spring 
           352 C: tension spring of bending correction mechanism corresponding to cyan 
           352 M: tension spring of bending correction mechanism corresponding to magenta 
           352 Y: tension spring of bending correction mechanism corresponding to yellow 
           352 K: tension spring of bending correction mechanism corresponding to black 
           354 : tension spring support 
           360 : bending correction mechanism 
           362 A: first spring 
           362 B: second spring 
           364 A: first spring support 
           364 B: second spring support 
           366 A: first spring-connecting portion 
           366 B: second spring-connecting portion 
         N: nozzle 
         P: sheet