Patent Publication Number: US-2009219370-A1

Title: Ink jet recording apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 61/032,374, filed Feb. 28, 2008. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an ink jet recording apparatus which ejects aqueous ink from an ink jet head to form an image on a paper. 
     BACKGROUND 
     An ink jet recording apparatus can record an image with high accuracy at high speed. Further, the ink jet recording apparatus adopts a non-impact system, so that noises are little. Moreover, the ink jet recording apparatus has an advantage that a color image is easily recorded by using multicolored inks. Therefore, the ink jet recording apparatus becomes common practice for home or business use. 
     However, in the ink jet recording apparatus, a cellulose fiber is swollen or untied especially in a plain paper by moisture in the inks, a phenomenon referred to as a rippling cockling occurs in the paper in a cycle of several to tens mm. For this reason, there is the defect that it is difficult for users to handle the paper after being printed. 
     In JP-A-10-217572, a configuration is disclosed in which while an ink jet head and a recording sheet are separated from each other, in a recording area where an ink is applied on the recording sheet, the rear surface of the recording sheet is supported by a mesh member having a heater which is disposed at an opposite side to the ink jet head. According to the configuration of JP-A-10-217572, a heating effect is sufficiently exhibited even though the recording sheet does not come in contact with the heater over the entire surface thereof, and further it is possible to always remove vapor which is evaporated from the rear surface of the recording sheet from the recording area to the outside. With the configuration of JP-A-10-217572, a difference between degrees of dryness on both sides of the recording sheet is reduced, and thus a bending of the recording sheet is significantly reduced or removed. 
     However, in the configuration of JP-A-10-217572, even though the recording sheet can be dried, since correction is not performed, curl and cockling cannot be completely corrected. 
     An object of the present invention is to provide an ink jet recording apparatus, which can efficiently dry a paper on which an image is formed by using ink. 
     SUMMARY 
     According to one aspect of the present invention, there is provided an ink jet recording apparatus including: an ink jet head in which a plurality of nozzles is arranged; a sub-scan driving unit which carries a recording medium to be formed with an image; a suction unit which sucks the recording medium on the sub-scan driving unit; and a heating unit which is disposed with respect to at least one place of the sub-scan driving unit in a direction perpendicular to a carrying direction of the recording medium with a gap therebetween. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view illustrating an ink jet recording apparatus viewed from a horizontal direction of a first embodiment. 
         FIG. 2  is a top view illustrating an ink jet head and a heat-fixing device of the first embodiment. 
         FIG. 3  is a cross-sectional view illustrating the heat-fixing device viewed from a horizontal direction of the first embodiment. 
         FIG. 4  is an enlarged top view illustrating a carrying belt of the first embodiment. 
         FIG. 5  is a top view illustrating a modified example of the heat-fixing device of the first embodiment. 
         FIG. 6  is a cross-sectional view illustrating a modified example of the heat-fixing device viewed from a horizontal direction of the first embodiment. 
         FIG. 7  is a top view illustrating another modified example of the heat-fixing device of the first embodiment. 
         FIG. 8  is a cross-sectional view illustrating an ink jet recording apparatus viewed from a horizontal direction of a second embodiment. 
         FIG. 9  is a cross-sectional view illustrating a heat-fixing device viewed from a horizontal direction of the second embodiment. 
         FIG. 10  is a top view illustrating the heat-fixing device of the second embodiment. 
         FIG. 11  is a top view illustrating a modified example of the heat-fixing device of the second embodiment. 
         FIG. 12  is a top view illustrating an ink jet head and a heat-fixing device of a third embodiment. 
         FIG. 13  is a top view illustrating a modified example of the ink jet head and the heat-fixing device of the third embodiment. 
         FIG. 14  is a block diagram illustrating a control system of the ink jet recording apparatus of the first embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments will be described. 
       FIG. 1  is a cross-sectional view illustrating an ink jet recording apparatus  1  viewed from a horizontal direction of a first embodiment.  FIG. 14  is a block diagram illustrating a control system of the ink jet recording apparatus  1  of the first embodiment. 
     A first paper cassette  100  and a second paper cassette  101  contain the recording mediums p which are different in size, respectively. A first paper feeding roller  102  withdraws the recording medium p corresponding to a selected size from the first paper cassette  100  to be carried to a pair of first carrying rollers  104  and a pair of resist rollers  106 . Similarly, a second paper feeding roller  103  withdraws the recording medium p corresponding to a selected size of the recording medium from the second paper cassette  101  to be carried to a pair of second carrying rollers  105  and the pair of resist rollers  106 . 
     A carrying belt  107  is applied with tension by a driving roller  108  and two driven rollers  109 . In a surface of the carrying belt  107 , holes are made at a predetermined interval. In addition, in the inside of the carrying belt  107 , a negative pressure chamber  111  is provided so as to be connected to a fan  110  in order to suck the recording medium p to the carrying belt  107 . 
     The driving roller  108  drives the carrying belt  107  so as to carry the recording medium p from an upstream side where the pair of the resist rollers  106  is formed as a paper feeding unit to a downstream side where a pair of first carrying rollers  112 , a pair of second carrying rollers  113 , and a pair of third carrying rollers  114  are formed as the paper feeding unit. A carrying direction of the recording medium p is a sub-scan direction when it is viewed from a recording operation in the ink jet recording apparatus  1 . 
     In the downstream side of the carrying direction of the recording medium p on the carrying belt  107 , a heat-fixing device  120  which heats the recording medium p where the image is formed is disposed. The heat-fixing device  120  will be described in detail later. 
     Above the carrying belt  107 , ink jet heads which eject inks to the recording medium according to image data are disposed on four lines. Specifically, from the upstream side, an ink jet head  115 C which ejects a cyan (C) ink, an ink jet head  115 M which ejects a magenta (M) ink, an ink jet head  115 Y which ejects a yellow (Y) ink, and an ink jet head  115 Bk which ejects a black (Bk) ink are disposed in this order. 
     In the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk, nozzles  500  which eject ink are disposed at a predetermined resolution along a width direction of the recording medium p, respectively (refer to  FIG. 2 ). That is, the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk are line type print heads in which plural nozzles  500  are arranged on a line. In the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk, the nozzles  500  are arranged in a direction perpendicular to the carrying direction of the recording medium p by the carrying belt  107 . The nozzles  500  are arranged so as to be positioned with a defined distance with respect to the recording medium p which is located on the carrying belt  107 . Here, an alignment direction of the nozzles  500  is a main scan direction. 
     The ink jet recording apparatus  1  of the first embodiment is provided with the line type ink jet heads  115 C,  115 M,  115 Y, and  115 Bk on the carrying belt  107  which carries the recording medium p. The ink jet heads  115 C,  115 M,  115 Y, and  115 Bk perform the recording operation on the recording medium p on the basis of image signals inputted. If the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk are a line type, any driving scheme thereof is sufficient. That is, in the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk, a scheme using thermoelectric conversion elements, a scheme using electrostrictive conversion elements, or other schemes such as an ink ejecting scheme are applicable. 
     The carrying belt  107  and the driving roller  108  are sub-scan driving units which relatively move the recording medium p and the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk in the sub-scan direction perpendicular to the alignment direction of the nozzles  500 . That is, the carrying belt  107  and the driving roller  108  perform a sub-scan driving process in which the recording medium p and the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk are relatively moved in the sub-scan direction perpendicular to the alignment direction of the nozzles  500 . 
     That is, the ink jet recording apparatus  1  of the first embodiment performs the recording operation on the recording medium p in the line scheme (one path recording scheme). A control unit  300  controls the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk to be driven on the basis of the image signals to perform a main scan driving process in which ink droplets are selectively ejected from the nozzles  500 . In addition, the control unit  300  drives the driving roller  108  by a driving motor  301 . The control unit  300  performs the sub-scan driving process in which the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk and the recording medium p are relatively moved in the sub-scan direction. The recording operation is performed by the main scan driving process and the sub-scan driving process. 
     Further, in the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk, a cyan (C) ink cartridge  116 C, a magenta (M) ink cartridge  116 M, a yellow (Y) ink cartridge  116 Y, and a black (Bk) ink cartridge  116 Bk in which respective colors are filled are provided. The ink jet head  115 C and the ink cartridge  116 C, the ink jet head  115 M and the ink cartridge  116 M, the ink jet head  115 Y and the ink cartridge  116 Y, and the ink jet head  115 Bk and the ink cartridge  116 Bk are connected through tubes  117 , respectively. 
     Here, an example of composition in aqueous inks of black, yellow, cyan, and magenta will be shown. 
     
       
         
           
               
             
               
                   
               
             
            
               
                 Black 
               
               
                 Self-dispersed carbon black dispersion liquid 
               
               
                 (Made by Cabot Specialty Chemicals Ink) 
               
            
           
           
               
               
               
               
            
               
                   
                 (Carbon black solid content concentration) 
                 8.0 
                 wt % 
               
               
                   
                 Glycerin 
                 30.0 
                 wt % 
               
               
                   
                 Ethylene glycol mono butyl ether 
                 0.5 
                 wt % 
               
               
                   
                 Surfynol 465 
                 1.0 
                 wt % 
               
               
                   
                 Proxel XL-2 (S) 
                 0.2 
                 wt % 
               
               
                   
                 Ion-exchange water remaining amount 
                 (60.3 
                 wt %) 
               
            
           
           
               
            
               
                 Yellow 
               
               
                 Self-dispersion yellow dispersion liquid 
               
               
                 (Made by Cabot Specialty Chemicals Ink) 
               
            
           
           
               
               
               
               
            
               
                   
                 (Yellow pigment solid content concentration) 
                 6.0 
                 wt % 
               
               
                   
                 Glycerin 
                 45.0 
                 wt % 
               
               
                   
                 Ethylene glycol mono butyl ether 
                 5.0 
                 wt % 
               
               
                   
                 Surfynol 465 
                 1.0 
                 wt % 
               
               
                   
                 Proxel XL-2 (S) 
                 0.2 
                 wt % 
               
               
                   
                 Ion-exchange water remaining amount 
                 (42.8 
                 wt %) 
               
            
           
           
               
            
               
                 Magenta 
               
               
                 Polymer dispersant dispersed magenta dispersion liquid 
               
               
                 (Made by Fuji Shikiso) 
               
            
           
           
               
               
               
               
            
               
                   
                 (Magenta pigment solid content concentration) 
                 6.0 
                 wt % 
               
               
                   
                 Glycerin 
                 45.0 
                 wt % 
               
               
                   
                 Diethylene glycol mono butyl ether 
                 5.0 
                 wt % 
               
               
                   
                 Surfynol 465 
                 1.0 
                 wt % 
               
               
                   
                 Proxel XL-2 (S) 
                 0.2 
                 wt % 
               
               
                   
                 Ion-exchange water remaining amount 
                 (42.8 
                 wt %) 
               
            
           
           
               
            
               
                 Cyan 
               
               
                 Polymer dispersant dispersed cyan dispersion liquid 
               
               
                 (Made by Fuji Shikiso) 
               
            
           
           
               
               
               
               
            
               
                   
                 (Cyan pigment solid content concentration) 
                 6.0 
                 wt % 
               
               
                   
                 Glycerin 
                 45.0 
                 wt % 
               
               
                   
                 Triethylene glycol mono butyl ether 
                 5.0 
                 wt % 
               
               
                   
                 Surfynol 465 
                 1.0 
                 wt % 
               
               
                   
                 Proxel XL-2 (S) 
                 0.2 
                 wt % 
               
               
                   
                 Ion-exchange water remaining amount 
                 (57.2 
                 wt %) 
               
               
                   
                   
               
            
           
         
       
     
     The above-mentioned ink includes water of 60.3 wt % as a maximum value or 42.8 wt % as a minimum value. Until the image is completely formed, it is necessary to dry the recording medium by evaporating the moisture down to an amount of moisture which is generally absorbed into the recording medium. 
     Next, an image formation by the ink jet recording apparatus  1  of the first embodiment will be described. 
     Firstly, when the control unit  300  obtains image data to be printed on the recording medium p via an external interface  302 , an image process begins. The control unit  300  transfers the image data subjected to the image process to the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk. Here, the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk are connected with respective colors of the ink cartridges  116 C,  116 M,  116 Y, and  116 Bk through tubes  117 , respectively. In the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk, proper inks are supplied on the basis of the image data. 
     The first paper feeding roller  102  or the second paper feeding roller  103  withdraws the recording medium p corresponding to the selected size one by one from the first paper cassette  100  or the second paper cassette  101 . The recording medium p is carried to the pair of the first carrying rollers  104  or the pair of the second carrying rollers  105  and the pair of the resist rollers  106 . 
     The pair of the resist rollers  106  corrects a skew of the recording medium p and begins to carry the recording medium at a predetermined timing. By reducing pressure in the negative pressure chamber  111 , air is drawn through holes of the carrying belt  107 . The recording medium p which is sucked on the carrying belt  107  is carried to a position facing the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk. Therefore, a distance between the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk and the recording medium p is maintained at a constant interval, for example, 0.5 to 2.0 mm. The control unit  300  is synchronized with the timing when the recording medium p is carried from the pair of the resist rollers  106 , and ejects the respective colors from the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk. Since the nozzles  500  of the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk are arranged along the width direction of the recording medium p, when the recording medium p is carried, a full color image is formed on the entire surface of the recording medium p. 
     After the Bk ink ejected from the ink jet head  115 Bk is finally landed on the recording medium p and a predetermined time lapses, the carrying belt  107  carries the recording medium p to the heat-fixing device  120 . The heat-fixing device  120  is embedded in the negative pressure chamber  111  at a position on the downstream of the ink jet head  115 Bk along the carrying direction of the recording medium p. The heat-fixing device  120  is a mechanism for evaporating the moisture which is included in the recording medium p in the middle of being passed. The recording medium p dried by the head-fixing device  120  is discharged to a discharge tray  118  by the pair of the first carrying rollers  112 , the pair of the second carrying rollers  113 , and the pair of the third carrying rollers  114 . 
     Next, a configuration of the heat-fixing device  120  of the first embodiment will be described.  FIG. 2  is a top view illustrating an ink jet head  115 C and a heat-fixing device  120  of the first embodiment.  FIG. 3  is a cross-sectional view illustrating the heat-fixing device  120  viewed from a horizontal direction of the first embodiment.  FIG. 4  is an enlarged top view illustrating a carrying belt  107  which comes in contact with the heat-fixing device  120  of the first embodiment. Here, the configuration of the nozzles  500  which are arranged in the ink jet head  115 C is shown in  FIG. 2 , and the ink jet head  115 M, the ink jet head  115 Y, and the ink jet head  115 Bk are also the same configuration as that of the ink jet head  115 C. 
     As shown in  FIG. 3 , the heat-fixing device  120  is embedded in the negative pressure chamber  111 . An arrow shows the carrying direction of the recording medium p, and the same is true in  FIG. 2  or later. The carrying belt  107  carries the recording medium p which is sucked on the heat-fixing device  120  by the negative pressure chamber  111 . An image forming surface of the recording medium p is placed to be faced upward, and the carrying belt  107  carries the recording medium p such that the image forming surface comes into contact with an external air. 
     As shown in  FIG. 4 , plural holes  400  are made in the carrying belt  107 . The holes  400  are provided, for example, at a 6 mm interval so as to be inclined with 45 degree with respect to the sub-scan direction. Therefore, the negative pressure chamber  111  can suck the recording medium p on the carrying belt  107 . 
     The heat-fixing device  120  includes plural heat elements  121  having a rectangular shape. Here, the heat-fixing device  120  which includes five heat elements  121  will be described. The carrying belt  107  on the heat-fixing device  120  is maintained by the heat elements  121  such that a surface temperature thereof becomes 60 to 70° C. The control unit  300  controls the temperature of the plural heat elements  121  by a temperature adjuster  304 . The temperature adjuster  304  adjusts the temperature of the carrying belt  107  which is provided on an arbitrary position of the heat-fixing device  120 . The heat-fixing device  120  includes a rubber heater. Here, even though the rubber heater is described as the heat element  121 , the heater is not limited thereto as long as that can be embedded in the negative pressure chamber  111 . 
     In the heat-fixing device  120 , the plural heat elements  121  are disposed such that the plural heat elements  121  are differently disposed from each other with respect to the carrying direction of the recording medium p, so that the plural heat elements  121  are disposed in parallel to the sub-scan direction by shifting their disposed axes. In addition, the plural heat elements  121  are embedded in the negative pressure chamber  111  so as to come into contact with the carrying belt  107 . The plural heat elements  121  are disposed such that at least one of the plural heat elements  121  faces the recording medium p in the width direction (main scan direction) while the carrying belt  107  carries the recording medium p on the heat-fixing device  120 . When viewed from the main scan direction, the plural heat elements  121  may be disposed so as to be overlapped. Therefore, the heat-fixing device  120  can heat the recording medium p over the entire surface thereof. 
     In addition, since the plural heat elements  121  are differently disposed from each other, at least a portion where the heat element  121  is not disposed along the main scan direction exists at any position on the carrying belt  107 . Therefore, even though on the heat-fixing device  120 , the carrying belt  107  can always carry the recording medium p with being sucked through the plural holes  400  which are provided in the carrying belt  107  by the negative pressure chamber  111 . 
     The heat-fixing device  120  of the first embodiment described above can heat the image-formed recording medium p, which contains the moisture in the ink, with being always sucked on the carrying belt  107 . The heat-fixing device  120  can evaporate the moisture while the cockling in the recording medium p is corrected to be flattened. For this reason, there is no cockling in the recording medium p which passes over the heat-fixing device  120 , and the ink formed as the image is also dried. 
     The heat-fixing device  120  heats the recording medium p from an opposite surface of the image forming surface. In the recording medium p on which the image is formed, the much moisture is unevenly distributed on the image forming surface. If the heat-fixing device  120  heats the recording medium p from the opposite surface of the image forming surface, the generated vapor is not through the internal of the recording medium p but directly diffused to the external from the image forming surface. Therefore, the recording medium p is not swollen by the generated vapor. 
     Next, a modified example of the heat-fixing device  120  of the first embodiment will be described.  FIG. 5  is a top view illustrating the heat-fixing device  120 .  FIG. 6  is a cross-sectional view illustrating the heat-fixing device  120  viewed from a horizontal direction. The same is true in the above-mentioned description other than the alignment of the heat elements  121 . 
     The heat-fixing device  120  includes the plural heat elements  121  having a rectangular shape. Here, the heat-fixing device  120  which includes five heat elements  121  will be described. The plural heat elements  121  are disposed so as to be constantly inclined with respect to the carrying direction of the recording medium p. The plural heat elements  121  have a positional relation in which they are shifted on the same axis along the main scan direction. The plural heat elements  121  are also provided on both ends of the main scan direction of the carrying belt  107 . In addition, while the carrying belt  107  carries the recording medium p on the heat-fixing device  120 , the plural heat elements  121  are disposed such that at least one of the plural heat elements  121  faces the recording medium p in the width direction (main scan direction). When viewed from the main scan direction, the plural heat elements  121  may be disposed so as to be overlapped. Therefore, the heat-fixing device  120  can heat the recording medium p over the entire surface thereof. 
     In addition, since the plural heat elements  121  are disposed so as not to come into contact with each other at a predetermined interval, at least a portion where the heat element  121  is not disposed along the main scan direction exists at any position on the carrying belt  107 . Therefore, even though on the heat-fixing device  120 , the carrying belt  107  can always carry the recording medium p with being sucked through the plural holes  400  which are provided in the carrying belt  107  by the negative pressure chamber  111 . 
     Even though the heat elements  121  are disposed as shown in  FIG. 5  and  FIG. 6 , the same effects can be obtained as that of the configuration where the heat elements  121  are disposed as shown in  FIG. 2  and  FIG. 3 . 
       FIG. 7  is a top view illustrating another modified example of the heat-fixing device  120  of the first embodiment. The same is true in the above-mentioned description other than the alignment of the heat elements  121 . 
     The heat-fixing device  120  includes one heat element  121  having a rectangular shape. The heat element  121  is disposed along the main scan direction so as to be constantly inclined with respect to the carrying direction of the recording medium p. Both ends of the heat element  121  are provided on both ends of the main scan direction of the carrying belt  107 . While the carrying belt  107  carries the recording medium p on the heat-fixing device  120 , the heat-fixing device  120  can heat the recording medium p over the entire surface thereof. 
     In addition, since the heat element  121  is disposed so as to be constantly inclined with respect to the carrying direction, at least a portion where the heat element  121  is not disposed along the main scan direction exists at any position on the carrying belt  107 . Therefore, even on the heat-fixing device  120 , the carrying belt  107  can always carry the recording medium p with being sucked through the plural holes  400  which are provided in the carrying belt  107  by the negative pressure chamber  111 . 
     Even though the heat elements  121  are disposed as shown in  FIG. 7 , the same effects can be obtained as that of the configuration where the heat elements  121  are disposed as shown in  FIG. 2  and  FIG. 3 . 
     Next, a second embodiment will be described.  FIG. 8  is a cross-sectional view illustrating the ink jet recording apparatus  1  viewed from a horizontal direction of a second embodiment.  FIG. 9  is a cross-sectional view illustrating the heat-fixing devices  130 C,  130 M,  130 Y, and  130 Bk viewed from a horizontal direction of the second embodiment. 
     In the second embodiment, configurations other than the heat-fixing device  130 C,  130 M,  130 Y, and  130 Bk which are provided instead of the heat-fixing device  120  of the first embodiment shown in  FIG. 1  are the same as those of the ink jet recording apparatus  1  shown in  FIG. 1 . In addition, the recording operation by the ink jet recording apparatus  1  is also the same as that of the first embodiment. 
     In the heat-fixing apparatus  130 C, the negative pressure chamber  111  is embedded in a position between the ink jet head  115 C and the ink jet head  115 M along the carrying direction of the recording medium p. The heat-fixing device  130 M is embedded in the negative pressure chamber  111  in a position between the ink jet head  115 M and the ink jet head  115 Y along the carrying direction of the recording medium p. The heat-fixing device  130 Y is embedded in the negative pressure chamber  111  in a position between the ink jet head  115 Y and the ink jet head  115 Bk along the carrying direction of the recording medium p. The heat-fixing device  130 Bk is embedded in the negative pressure chamber  111  in a position on the downstream of the ink jet head  115 Bk along the carrying direction of the recording medium p. 
       FIG. 10  is a top view illustrating the heat-fixing device  130 C of the second embodiment. Here, a configuration of the heat-fixing device  130 C will be described, and configurations of the heat-fixing device  130 M, the heat-fixing device  130 Y, and the heat-fixing device  130 Bk are also the same as that of the heat-fixing device  130 C. 
     The heat-fixing device  130 M includes the plural heat elements  131  having a rectangular shape. Here, the heat-fixing device  130 M which includes five heat elements  131  will be described. In the heat-fixing device  120 , the plural heat elements  121  are disposed such that the plural heat elements  121  are differently disposed from each other with respect to the carrying direction of the recording medium p, so that the plural heat elements  131  are disposed in parallel to the sub-scan direction by shifting their disposed axes. The plural heat elements  121  are controlled by the temperature adjuster  304  which is provided on arbitrary position of the heat-fixing device  120  such that the surface temperature of the carrying belt  107  on the heat-fixing device  120  is maintained to become 60 to 70° C. 
     Similar to the disposition of the plural heat elements  121  shown in  FIG. 5 , the plural heat elements  131  are disposed such that at least one of the plural heat elements  131  faces the recording medium p in the width direction (main scan direction) while the carrying belt  107  carries the recording medium p on the heat-fixing device  120 . Therefore, the heat-fixing device  130  can heat the recording medium p over the entire surface thereof. Since the plural heat elements  121  are differently disposed from each other, even on the heat-fixing device  130 , the carrying belt  107  can carry the recording medium p with being always sucked through the plural holes  400  which are provided in the carrying belt  107  by the negative pressure chamber  111 . 
     The heat-fixing apparatus  130 C of the second embodiment described above can heat the image-formed recording medium p, which contains the moisture in the ink, with being always sucked on the carrying belt  107 . In addition, the heat-fixing device  130 C heats the recording medium p on which the image is formed with the C ink immediately after the C ink ejected from the ink jet head  115 C is landed on the recording medium p. 
     Similarly, the heat-fixing device  130 M heats the recording medium p on which the image is formed with the M ink immediately after the M ink ejected from the ink jet head  115 M is landed on the recording medium p. The heat-fixing device  130 Y heats the recording medium p on which the image is formed with the Y ink immediately after the Y ink ejected from the ink jet head  115 Y is landed on the recording medium p. The heat-fixing device  130 Bk heats the recording medium p on which the image is formed with the Bk ink immediately after the Bk ink ejected from the ink jet head  115 Bk is landed on the recording medium p. 
     In the second embodiment, since the heat-fixing device  130 C, the heat-fixing device  130 M, the heat-fixing device  130 Y, and the heat-fixing device  130 Bk can dry the recording medium p immediately after the image is formed by the inks ejected from the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk, the moisture can be effectively evaporated in a state where the cockling in the recording medium p is corrected to be flattened. For this reason, there is no cockling in the recording medium p which is finally passed over the heat-fixing device  130 Bk, and the ink formed as the image is also dried. 
     An effect of heating the recording medium p from the opposite surface of the image forming surface by the heat-fixing device  130 C is the same as the effect described in the first embodiment. 
     Next, a modified example of the heat-fixing device  130 C of the second embodiment will be described.  FIG. 11  is a top view illustrating the heat-fixing device  130 C. Here, a configuration of the heat-fixing device  130 C will be described, and configurations of the heat-fixing device  130 M, the heat-fixing device  130 Y, the heat-fixing device  130 Bk are also the same as that of the heat-fixing device  130 C. 
     The heat-fixing device  130 C includes plural heat elements  131  having a rectangular shape. The plural heat elements  131  have the same alignment as that of the plural heat elements  121  described in  FIG. 5 , and constantly incline with respect to the carrying direction of the recording medium p. Therefore, the heat-fixing device  130 C heats the recording medium p over the entire surface on which the image is formed with the C ink immediately after the C ink ejected from the ink jet head  115 C is landed on the recording medium p. 
     Even though the heat elements  131  are disposed as shown in  FIG. 11 , the same effects can be obtained as that of the configuration where the heat elements  131  are disposed as shown in  FIG. 10 . 
     Next, a third embodiment will be described.  FIG. 12  is a top view illustrating the ink jet head  115 C and a heat-fixing device  140  of a third embodiment. 
     In the third embodiment, other configurations except for the heat-fixing device  140  and the ink jet heads  115 C,  115 M,  115 Y, and  115 Bk which are provided on the same position instead of the heat-fixing device  120  of the first embodiment shown in  FIG. 1  are the same as those of the ink jet recording apparatus  1  shown in  FIG. 1 . In addition, the recording operation by the ink jet recording apparatus  1  is also the same as that of the first embodiment. Here, the configuration of the ink jet head  115 C is shown in  FIG. 12 , and the ink jet head  115 M, the ink jet head  115 Y, and the ink jet head  115 Bk are also the same configuration as that of the ink jet head  115 C. 
     As shown in  FIG. 12 , in the ink jet head  115 C, plural short heads  600  are arranged in parallel. In general, as the ink jet head becomes longer, yield thereof is worsened and the cost is increased. In the ink jet head  115 C of the third embodiment, the plural short heads  600  are disposed so that the lengthening is implemented. Here, the ink jet head  115 C which includes five heads  600  will be described. 
     In the ink jet head  115 C, the plural heads  600  are disposed such that the plural heads are differently disposed from each other with respect to the carrying direction of the recording medium p, so that the plural heads  600  are disposed in parallel to the sub-scan direction by shifting their disposed axes. The nozzles  500  of the head  600  which is included in the ink jet head  115 C are arranged in the width direction (a direction perpendicular to the carrying direction of the recording medium p) of the recording medium p. 
     In addition, in the heat-fixing device  140 , the plural heat elements  141  are disposed such that the plural heat elements  141  are differently disposed from each other with respect to the carrying direction of the recording medium p, so that the plural heat elements  141  are disposed in parallel to the sub-scan direction by shifting their disposed axes. Here, the number of the plural heat elements  141  is the same as that of the plural heads  600  which are included in the ink jet head  115 C. Therefore, the number of the plural heat elements  141  is five. 
     The plural heat elements  141  are provided on a position facing the heads  600  which are included in the ink jet head  115 C along the sub-scan direction. All relative distances along the sub-scan direction between the heat elements  141  and the heads  600 , which are in facing relation therebetween, are constant. That is, if the alignments of the nozzles  500  of the heads  600  which are included in the ink jet head  115 C are shifted along the sub-scan direction, the alignments are included in the alignments of the plural heat elements  141 . Therefore, the heat-fixing device  140  can heat an exact portion of the recording medium p on which the image is formed. 
     In addition, since the plural heat elements  141  are differently disposed from each other, even on the heat-fixing device  140 , the carrying belt  107  can carry the recording medium p with being always sucked through the plural holes  400  which are provided in the carrying belt  107  by the negative pressure chamber  111 . The heat-fixing device  140  of the third embodiment can heat the image-formed recording medium p, which contains the moisture in the ink, with being always sucked on the carrying belt  107 . 
     Here, in the ink jet head  115 C, since the plural heads  600  are differently disposed from each other with respect to the carrying direction of the recording medium p, the timings when the aqueous C inks ejected from the nozzles  500  are landed on the recording medium p become different according to the positions of the heads  600  even though the inks are landed on one line in the width direction of the same recording medium p. That is, times for permeating the recording medium p by the aqueous C ink also become different. In this recording medium p, when the one line in the width direction is dried at the same time, drying marks occur. 
     In the third embodiment, all relative distances between the heat elements  141  and the heads  600  along the sub-scan direction, which are in facing relation therebetween, are constant. For this reason, the period of time from landing the aqueous C ink on the recording medium p ejected from the nozzles  500  until the heat elements  141  begin to heat is always constant independently from the position of the heads  600 . 
     Therefore, in the heat-fixing device  140 , the drying marks on the recording medium p are prevented, and further the heat-fixing device  140  can evaporate the moisture while the cockling in the recording medium p is corrected to be flattened. There is no cockling in the recording medium p which is passed over the heat-fixing device  140 , and the ink formed as the image is also dried. 
     An effect of heating the recording medium p from the opposite surface of the image forming surface by the heat-fixing device  140  is the same as the effect described in the first embodiment. 
     Next, a modified example of the heat-fixing device  140  of the third embodiment will be described.  FIG. 13  is a top view illustrating the ink jet head  115 C and the heat-fixing device  140 . The same is true in the above-mentioned description except for the alignments of the heads  600  and the heat elements  141 . 
     The ink jet head  115 C includes the plural heads  600  having a rectangular shape. Here, the ink jet head  115 C which includes five heats  600  will be described. The plural heads  600  are disposed so as to be constantly inclined with respect to the carrying direction of the recording medium p. The plural heads  600  have a positional relation in which they are shifted on the same axis along the main scan direction. Therefore, similar to the inclination of the heads  600 , the nozzles  500  which are arranged in the heads  600  are also disposed so as to be constantly inclined with respect to the carrying direction of the recording medium p. 
     In the heat-fixing device  140 , the plural heat elements  141  are disposed so as to be the same inclination as that of the nozzles  500  with respect to the carrying direction of the recording medium p. The plural heat elements  141  have a positional relation in which they are shifted on the same axis along the main scan direction. Here, the number of the plural heat elements  141  is the same as that of the plural heads  600  which are included in the ink jet head  115 C. Therefore, the number of the plural heat elements  141  is five. 
     The plural heat elements  141  are provided on a position facing the heads  600  which is included in the ink jet head  115 C along the sub-scan direction. All relative distances along the sub-scan direction between the heat elements  141  and the heads  600 , which are in facing relation therebetween, are constant. That is, if the alignments of the nozzles  500  of the heads  600  which are included in the ink jet head  115 C are shifted along the sub-scan direction, the alignments are included in the alignments of the plural heat elements  141 . Therefore, the heat-fixing device  140  can heat an exact portion of the recording medium p on which the image is formed. 
     In addition, the plural heat elements  141  are disposed so as not to come into contact with each other at a predetermined interval such that at least a portion where the heat element  141  is not disposed along the main scan direction exists. Therefore, the heat-fixing apparatus  140  can heat the image-formed recording medium p, which contains the moisture in the ink, with being always sucked on the carrying belt  107 . 
     The configuration shown in  FIG. 13  is the same as that shown in  FIG. 12 , and all relative distances along the sub-scan direction between the heat elements  141  and the heads  600 , which are in facing relation therebetween, are constant. For this reason, the period of time from landing the aqueous C ink on the recording medium p ejected from the nozzles  500  until the heat elements  141  begin to heat is always constant independently from the position of the heads  600 . 
     Therefore, in the heat-fixing device  140 , the drying marks on the recording medium p are prevented, and further the heat-fixing device  140  can evaporate the moisture while the cockling in the recording medium p is corrected to be flattened. There is no cockling in the recording medium p which is passed over the heat-fixing device  140 , and the ink formed as the image is also dried. 
     With the configurations of the first embodiment, the second embodiment, and the third embodiment, it is possible to perform the printing while drying the recording medium p at high speed.