Patent Publication Number: US-8118394-B2

Title: Droplet ejecting device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2008-126543 filed May 13, 2008. 
     BACKGROUND 
     Technical Field 
     The present invention relates to a droplet ejecting device. 
     SUMMARY 
     An aspect of the present invention is a droplet ejecting device including: plural droplet ejecting heads that eject droplets; a transporting body, disposed to face nozzle surfaces of the droplet ejecting heads, that transports a recording medium; and a head holding member that holds the droplet ejecting heads movably along droplet ejecting directions respectively. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention will be described in detail with reference to the following figures, wherein: 
         FIG. 1  is a schematic front view showing the structure of an inkjet recording device relating to the present exemplary embodiment; 
         FIG. 2  is a schematic perspective view showing the structure of the inkjet recording device relating to the present exemplary embodiment; 
         FIG. 3  is a schematic side view explaining operation of an inkjet recording head structuring the inkjet recording device relating to the present exemplary embodiment; 
         FIG. 4  is a schematic side view explaining operation of the inkjet recording head structuring the inkjet recording device relating to the present exemplary embodiment; 
         FIG. 5  is an exploded perspective view showing an up/down moving mechanism of the inkjet recording head structuring the inkjet recording device relating to the present exemplary embodiment; 
         FIG. 6  is an exploded perspective view showing the structure of a capping unit structuring the inkjet recording device relating to the present exemplary embodiment; 
         FIGS. 7A through 7C  are schematic sectional views explaining operation of the capping unit structuring the inkjet recording device relating to the present exemplary embodiment; 
         FIGS. 8A and 8B  are schematic sectional views explaining operation of the capping unit structuring the inkjet recording device relating to the present exemplary embodiment, where  FIG. 8A  illustrates a case using a pressure-applying pump and  FIG. 8B  illustrates a case using a suction pump; 
         FIG. 9  is a schematic sectional view explaining operation of the capping unit structuring the inkjet recording device relating to the present exemplary embodiment; 
         FIG. 10  is a schematic side view explaining operation of the inkjet recording head structuring the inkjet recording device relating to the present exemplary embodiment; 
         FIG. 11  is a schematic side view explaining operation of the inkjet recording head structuring the inkjet recording device relating to the present exemplary embodiment; 
         FIG. 12  is a schematic side view explaining operation of the inkjet recording head structuring the inkjet recording device relating to the present exemplary embodiment; 
         FIG. 13A  is a schematic diagram explaining operation of the inkjet recording device relating to the present exemplary embodiment, and  FIG. 13B  is a comparative example thereof; 
         FIG. 14  is a schematic side view explaining operation of the inkjet recording head structuring the inkjet recording device relating to the present exemplary embodiment; 
         FIG. 15  is an explanatory diagram explaining operation of the inkjet recording head structuring the inkjet recording device relating to the present exemplary embodiment; and 
         FIG. 16  is a schematic front view showing a modified example of the inkjet recording device relating to the present exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Preferred exemplary embodiments of the present invention are described in detail hereinafter on the basis of the examples illustrated in the drawings. The schematic structure of an inkjet recording device  10 , that serves as an example of a droplet ejecting device relating to the present invention, is shown in  FIG. 1 . Accordingly, hereinafter, explanation will be given with droplet ejecting heads being inkjet recording heads  20 , and a recording medium on which an image is recorded by the droplet ejecting heads being a recording sheet P. 
     As shown in  FIG. 1 , the inkjet recording device  10  includes: a sheet feeding section  12  that accommodates the recording sheets P before images are recorded thereon; an image recording section  14  that records an image on the recording sheet P supplied from the sheet feeding section  12 ; a transporting section  16  that transports the recording sheet P to the image recording section  14 ; and a sheet discharging section  18  that accommodates the recording sheets P after images are recorded thereon by the image recording section  14 . 
     The image recording section  14  includes the inkjet recording heads  20 . The inkjet recording heads  20  are lined up in the order of yellow (Y), magenta (M), cyan (C) and black (K) from the downstream side with respect to the transporting direction of the recording sheet P. Ink droplets are ejected by known mechanisms of a thermal system, a piezoelectric system, or the like. 
     Note that various types of inks, such as aqueous (water) inks, oily inks, solvent-based inks, and the like can be used as the inks. Ink tanks (not shown) that supply inks to the respective inkjet recording heads  20 Y,  20 M,  20 C,  20 K are provided at the inkjet recording device  10 . 
     The inkjet recording heads  20 Y,  20 M,  20 C,  20 K have nozzle surfaces  22 Y,  22 M,  22 C,  22 K at which plural nozzles (not shown) are formed. The nozzle surfaces  22 Y,  22 M,  22 C,  22 K have a recordable region that is the same extent as or larger than the maximum width of the recording sheets P for which image recording at the inkjet recording device  10  is supposed. 
     In explanation hereinafter that is common to the respective inkjet recording heads  20 Y,  20 M,  20 C,  20 K, the reference letters Y, M, C, K are omitted. 
     The inkjet recording heads  20  are held at a head holder (a head holding member)  40 , and are disposed above a transporting drum  26  (to be described later) that structures the transporting section  16 , and are respectively disposed along the peripheral direction of the outer peripheral surface of the transporting drum  26 . Namely, the respective inkjet recording heads  20  are disposed at predetermined angles (for example, about a rotating shaft  32  as a center) with respect to one another. 
     Up/down moving mechanisms  42  serving as an approaching/separating section are provided at the head holder  40  for the respective inkjet recording heads  20 , and can make the respective inkjet recording heads  20  approach and move away from the transporting drum  26  (move up and down) along the angles at which the inkjet recording heads  20  are disposed. 
     Further, a frame body (horizontal moving section)  44 , that extends in the direction orthogonal to the transporting direction of the recording sheet P, is provided beneath the head holder  40  as shown in  FIG. 2 . The head holder  40  can move horizontally within the frame body  44  between a facing position, at which the head holder  40  faces the transporting drum  26 , and a withdrawn position, at which the head holder  40  is withdrawn from the facing position. 
     With regard to the structure that moves the head holder  40  horizontally, although not illustrated, the head holder  40  may be moved horizontally by using a linear motor. Or, the head holder  40  may be moved horizontally by using a rotating motor via a rack and pinion. 
     Wiper units  46  (see  FIG. 3 ) serving as a cleaning section and maintenance units  48  serving as a capping section are provided so as to correspond to the respective inkjet recording units  20  at the side of the withdrawn position of the head holder  40  in the frame body  44 . The wiper units  46  are disposed at the transporting drum  26  side. 
     As shown in  FIG. 4 , a wiper blade  50  that cleans (wipes) the nozzle surface  22  of the inkjet recording head  20  is provided at the wiper unit  46 . A capping member  52 , that is for removing contaminating substances within the nozzles (not shown) of the inkjet recording head  20 , is provided at the maintenance unit  48  (this will be described later). 
     On the other hand, as shown in  FIG. 1 , the transporting section  16  has: a pick-up drum  24  that takes-out one-by-one the recording sheets P that are in the sheet feeding section  12 ; the transporting drum  26  serving as a transporting body that transports the recording sheet P to the inkjet recording heads  20  of the image recording section  14 , and whose printing surface (surface) faces the inkjet recording heads  20 ; and a feed-out drum  28  that feeds the recording sheet P, on which an image has been recorded, out to the sheet discharging section  18 . Further, the pick-up drum  24 , the transporting drum  26  and the feed-out drum  28  are respectively structured such that the recording sheet P is held at the peripheral surface thereof by an electrostatic attraction section, or by a non-electrostatic attraction section that utilizes suction, adhesion, or the like. 
     Grippers  30 , that nip and hold the transporting direction downstream side end portions of the recording sheets P, are provided at the pick-up drum  24 , the transporting drum  26  and the feed-out drum  28 . For example, two sets of the grippers  30  are provided at each of the drums  24 ,  26 ,  28 . In this case, each of these three drums  24 ,  26 ,  28  is structured so as to be able to hold up to two of the recording sheets P at the peripheral surface of the drum. The grippers  30  are provided within concave portions  24 A,  26 A,  28 A, two of which are formed at the peripheral surface of each of the drums  24 ,  26 ,  28 . 
     Namely, rotating shafts  34  are placed pivotally at predetermined positions within the concave portions  24 A,  26 A,  28 A of the respective drums  24 ,  26 ,  28 , substantially parallel to rotating shafts  32  of the drums  24 ,  26 ,  28 . The plural grippers  30  are fixed to the rotating shafts  34  so as to be spaced apart from one another by predetermined intervals (e.g., uniform intervals) in the axial direction. Accordingly, due to the rotating shafts  34  rotating in both forward and reverse directions by unillustrated actuators, the grippers  30  rotate in both forward and reverse directions substantially along the peripheral directions of the respective drums  24 ,  26 ,  28 , and can nip/hold or release the transporting direction downstream side end portions of the recording sheets P. 
     Namely, the grippers  30  rotate such that the distal end portions thereof project-out slightly from the peripheral surfaces of the respective drums  24 ,  26 ,  28 . Due thereto, at a transfer position  36  where the peripheral surface of the pick-up drum  24  and the peripheral surface of the transporting drum  26  oppose one another, the recording sheet P can be transferred from the grippers  30  of the pick-up drum  24  to the grippers  30  of the transporting drum  26 . Further, at a transfer position  38  where the peripheral surface of the transporting drum  26  and the peripheral surface of the feed-out drum  28  oppose one another, the recording sheet P can be transferred from the grippers  30  of the transporting drum  26  to the grippers  30  of the feed-out drum  28 . 
     Although not illustrated, a controlling section for the inkjet recording heads  20  and a system controlling section are provided at the inkjet recording device  10 . The controlling section for the inkjet recording heads  20  determines the ejection timings of ink drops and the nozzles to be used in accordance with image signals, and applies driving signals to the nozzles. The system controlling section controls the overall operation of the inkjet recording device  10 . 
     The up/down moving mechanism and the maintenance unit will be described hereinafter. 
     As shown in  FIG. 5 , as an example of the up/down moving mechanism  42 , guide rails  54 ,  56  for the respective inkjet recording heads  20  are provided at the both longitudinal direction end portions of the head holder  40  along the peripheral direction of the outer peripheral surface of the transporting drum  26  (radially along radial directions of the transporting drum  26 ) in the state in which the head holder  40  faces the transporting drum  26 , such that the angles of the guide rails  54 ,  56  differ from one another. 
     The guide rails  54 ,  56  are substantially U-shaped and guide the inkjet recording heads  20 . Further, the guide rails  54 ,  56  are provided in a state of overlapping one another. The guide rail  56  is fixed to the head holder  40 , and the guide rail  54  slides along the guide rail  56 . 
     A quadrangular pedestal (not shown) that is structured at the guide rail  56  is provided at the lower end portion of the guide rail  56 . A stepping motor  58  is disposed at this pedestal. A ball screw  60  is connected to the stepping motor  58 , and the ball screw  60  is rotated a predetermined angle by the driving of the stepping motor  58 . Note that the stepping motors  58  are provided at both longitudinal direction end portions of the inkjet recording head  20  and are made to be synchronous with one another. 
     On the other hand, a quadrangular guide plate  54 A that is structured at the guide rail  54  is provided at the lower end portion of the guide rail  54 . A screw hole  62  is formed in the central portion of the guide plate  54 A, and the ball screw  60  is screwed therein. Therefore, when the ball screw  60  rotates due to the driving of the stepping motor  58 , the guide rail  54  slides with respect to the guide rail  56  along the ball screw  60  via the guide plate  54 A. 
     A shaft-receiving portion  64  is provided at the upper end side of the guide rail  54 . Shafts  66 , that project-out substantially perpendicularly from the both end surfaces of the inkjet recording head  20 , can be supported at the shaft-receiving portions  64 . Therefore, in accordance with the sliding movement of the guide rails  54 , the inkjet recording head  20  moves up and down (approaches and moves away from the outer peripheral surface of the transporting drum  26  along the radial direction), via the shaft-supporting portions  64  and the shafts  66 . 
     Note that, here, there is a structure in which the guide rails  54  are moved up and down and the inkjet recording heads  20  are moved up and down by using the ball screws  60 . However, because it suffices to be able to move the inkjet recording heads  20  up and down, the present invention is not limited to this structure. For example, the inkjet recording heads  20  may be moved by racks and pinions in accordance with racks that are provided at the guide rails, although such a structure is not illustrated. 
     Further, here, two of the stepping motors  58  are provided for the one inkjet recording head  20  and are made to be synchronous with one another. However, one motor may be provided, and the up/down moving mechanism  42  may be provided at the longitudinal direction central portion of the inkjet recording head  20 , or the up/down moving mechanism  42  may be provided at the both longitudinal direction end portions of the inkjet recording head  20  and the driving force of the motor may be transmitted to the both longitudinal direction end portions of the inkjet recording head  20  via a pulley and a belt or the like. 
     On the other hand, as shown in  FIG. 4 , the wiper unit  46  has the wiper blade  50  that is structured by a plate-shaped elastic material such as rubber or the like. The wiper blade  50  is structured so as to, at the time of carrying out the wiping operation, be able to slidingly rub (wipe) the nozzle surface  22  of the inkjet recording head  20  at a predetermined pressure (pressure to the extent of not damaging the water-repellant film of the nozzle surface  22 ), due to the inkjet recording head  20  moving in the transverse direction (the direction of arrow A) that is orthogonal to the transporting direction of the recording sheet P. Due thereto, the nozzle surface  22  can be wiped well. 
     As shown in  FIG. 6 , the maintenance unit  48  includes mainly a box body  68  that is rectangular parallel/piped shape and the capping member  52  that is shaped as a box and is accommodated to be movable (as will be described later) along the up/down direction and the longitudinal direction of the box body  68 . Cam grooves  70 ,  72 ,  74 ,  76  are formed in side walls  68 A that run along the longitudinal direction of the box body  68 . 
     The shapes of the cam grooves  70 ,  72 ,  74 ,  76  are slightly different from one another. The cam grooves  70  form linear long grooves  78 . At the cam grooves  72 ,  74 ,  76 , inclined portions  80 , that are inclined downward moving away from long grooves  78  which are similar to the long grooves  78  formed on the cam grooves  70 , are connected to the long grooves  78 . 
     The positions of the long grooves  78  of the cam grooves  70 ,  72 ,  74 ,  76  are substantially the same height. The lengths of the long grooves  78  are shorter at the cam grooves  74  than at the cam grooves  72 , and the angles of inclination of the inclined portions  80  are steeper at the cam grooves  74  than at the cam grooves  72 . Further, the lengths of the long grooves  78  are shorter at the cam grooves  76  than at the cam grooves  74 , and the angles of inclination of the inclined portions  80  are steeper at the cam grooves  76  than at the cam grooves  74 . 
     On the other hand, a long-plate-shaped holding plate  82  is provided at the lower portion of the capping member  52 . Guide pins  84  project-out from the both end surfaces that run along the longitudinal direction of the holding plate  82 , in correspondence with the cam grooves  70 ,  72 ,  74 ,  76 . 
     As shown in  FIG. 2 , a push plate  86  is provided at the one end portion of the holding plate  82 , which one end portion is positioned at the side opposite the transporting drum  26  side. As shown in  FIGS. 7A through 7C  ( FIGS. 7A through 7C  are drawings typifying the box body  68  and the capping member  52 ), the end surface of the inkjet recording head  20  can contact the push plate  86  such that the push plate  86  is pushed by the horizontal movement of the inkjet recording head  20 . 
     One end portion of a coil spring (an urging member)  88  is attached to the other end portion of the holding plate  82 . The other end portion of the coil spring  88  is attached to the box body  68 . In the state of the coil spring  88  (see  FIG. 7A ), the capping member  52  is urged toward the transporting drum  26  within the box body  68 . 
     In this state, the guide pins  84 , that are engaged with the cam grooves  70  of the box body  68 , are engaged with the long grooves  78 . However, the other guide pins  84  are engaged with the inclined portions  80  of the cam grooves  72 ,  74 ,  76  (see  FIG. 6 ), and, as shown in  FIG. 7A , the capping member  52  is accommodated in a state of being tilted with respect to the box body  68 . 
     On the other hand, as shown in  FIG. 7B , when, due to horizontal movement of the inkjet recording head  20 , the end surface of the inkjet recording head  20  contacts the push plate  86  of the holding plate  82  and pushes the push plate  86 , the capping member  52  moves in a direction of moving away from the transporting drum  26  against the urging force of the coil spring  88 . 
     Due thereto, the guide pins  84  move along the long grooves  78  of the cam grooves  70  of the box body  68 , and the guide pins  84 , that are engaging with the inclined portions  80  of the cam grooves  72 ,  74 ,  76  (see  FIG. 6 ), move from the inclined portions  80  to the long grooves  78 . 
     Because the positions of the long grooves  78  of the cam grooves  70 ,  72 ,  74 ,  76  are substantially the same heights, the capping member  52  is held horizontal. In this state, as shown in  FIG. 7C , the inkjet recording head  20  moves toward the capping member  52 , and an airtight (sealing) state is formed between the capping member  52  and the nozzle surface  22  of the inkjet recording head  20 . 
     At this time, as shown in  FIG. 8A , pressure is applied to the ink within the inkjet recording head  20  by using a pressure-applying pump (clogging preventing section)  92  that is for supplying ink from each ink tank  90  to the inkjet recording head  20 . Due thereto, ink drops are ejected from the nozzles, and contaminating substances (ink that has hardened and the like) that are clogged within the nozzles are removed (contaminating substance removing process). 
     Other than the pressure-applying pump  92 , as shown in  FIG. 8B , by using a suction pump (clogging preventing section)  94  that sucks ink from the interior of the capping member  52  and that will be described later, the contaminating substances within the nozzles may be sucked out by the suction force of the suction pump  94 . Hereinafter, the clogging preventing section will be described by using the suction pump  94 . 
     When the process of removing contaminating substances from the nozzles of the inkjet recording head  20  ends, there is a state in which ink has accumulated at the floor surface of the capping member  52 . However, as shown in  FIG. 9 , when the inkjet recording head  20  is moved away from the push plate  86 , the capping member  52  is urged within the box body  68  by the coil spring  88  in a direction of approaching the transporting drum  26 . 
     Due thereto, the guide pins  84  move following the shapes of the respective cam grooves  70 ,  72 ,  74 ,  76  (see  FIG. 6 ), and the capping member  52  tilts within the box body  68 . Due thereto, the ink that has accumulated within the capping member  52  can be gathered at one place thereat. 
     Here, by subjecting the inner wall surfaces of the capping member  52  to a water repelling treatment, the ink within the capping member  52  can be made to flow smoothly, and the ability to discharge the ink can be improved. Further, a discharge opening  96  is formed in the floor surface of the capping member  52 , and the ink within the capping member  52  is discharged-out to the exterior through this discharge opening  96 . A pass-through opening  98  is formed in the box body  68 . One end portion of an elastic tube  100  is connected to the discharge opening  96  and, via the pass-through opening  98 , the other end portion of the elastic tube  100  is connected to the suction pump  94 . 
     As described above, the suction pump  94  is operated at the time when the airtight state between the capping member  52  and the nozzle surface  22  of the inkjet recording head  20  is formed, and the contaminating substances within the nozzles can be sucked. However, after the capping member  52  is tilted within the box body  68 , the suction pump  94  is again operated and sucks the ink that is within the capping member  52  from the discharge opening  96  and can discharge it to waste ink tank  90 . 
     Operation of the inkjet recording device  10 , that is structured as described above, will be described next. 
     As shown in  FIG. 1 , the recording sheet P that is picked-up and held one-by-one from the sheet feeding section  12  by the grippers  30  of the pick-up drum  24 , is transported while being stuck to the peripheral surface of the pick-up drum  24 , and, at the transfer position  36 , is transferred from the grippers  30  of the pick-up drum  24  to the grippers  30  of the transporting drum  26 . 
     While being stuck to the transporting drum  26 , the recording sheet P that is held by the grippers  30  of the transporting drum  26  is transported to the image recording position of the inkjet recording heads  20 , and an image is formed on the printing surface thereof by ink drops ejected from the inkjet recording heads  20 . 
     The recording sheet P on whose printing surface an image has been formed is, at the transfer position  38 , transferred from the grippers  30  of the transporting drum  26  to the grippers  30  of the feed-out drum  28 . Then, the recording sheet P that is held by the grippers  30  of the feed-out drum  28  is transported while being stuck to the feed-out drum  28 , and is fed to the sheet discharging section  18 . In this way, the series of image formation ends. 
     On the other hand, at the time of carrying out maintenance on the inkjet recording head  20 , first, as shown in  FIG. 3 , the inkjet recording head  20  is moved from a recording height P (the solid line) at the time of image formation to a cleaning height R (the imaginary line). 
     At this time, the stepping motors  58  shown in  FIG. 5  are driven, the ball screws  60  rotate, and the inkjet recording head  20  is moved, via the guide rails  54  and with respect to the head holder  40 , upward along the radial direction of the transporting drum  26  (recording height P shown in FIG.  3 →cleaning height R). As shown in  FIG. 4 , this cleaning height R is a height at which the wiper unit  46  and the nozzle surface  22  of the inkjet recording head  20  can contact. 
     Next, as shown in  FIG. 4 , the head holder  40  moves horizontally along the frame body  44  (illustration of the frame body  44  is omitted here) in a direction of withdrawing from the region above the transporting drum  26 . Because the wiper blade  50  that structure the wiper unit  46  is disposed on the locos of movement of the inkjet recording head  20 , due to the horizontal movement of the head holder  40 , the nozzle surface  22  of the inkjet recording head  20  is slidingly rubbed by the wiper blade  50  (cleaning process). The contaminating substances and the like, that adhere to the nozzle surface  22  of the inkjet recording head  20 , are thereby removed. 
     Here, as shown in  FIG. 7A  and  FIG. 7B , the push plate  86  of the capping member  52  that structure the maintenance unit  48  is disposed on the locus of movement of the inkjet recording head  20 . The capping member  52  is pushed by the end surface of the inkjet recording head  20  via the push plate  86  against the urging force of the coil spring  88 . Due thereto, the guide pins  84  move via the cam grooves  70 ,  72 ,  74 ,  76 , and the capping member  52  is held horizontal from the state in which it is inclined with respect to the box body  68 . 
     In this state, as shown in  FIG. 7B , a gap is provided between the capping member  52  and the nozzle surface  22  of the inkjet recording head  20 . From this state, the stepping motors  58  shown in  FIG. 5  are driven, and each inkjet recording head  20  moves downward along radial direction of the transporting drum  26  with respect to the head holder  40  (cleaning height R shown in FIG.  10 →attached height Q). Due thereto, as shown in  FIG. 7C , the nozzle surface  22  is covered by the capping member  52  and is in airtight state. 
     Next, as shown in  FIG. 8B , the interior of the capping member  52  is made to be negative pressure by the suction pump  94 , and the liquid within the nozzles of the inkjet recording head  20  is sucked (contaminating substance removing process). Clogs and the like within the nozzles due to contaminating substances such as hardened ink and the like are thereby eliminated. 
     Here, as shown in  FIG. 7C , by disposing the capping member  52  substantially parallel to the nozzle surface  22 , the nozzle interiors are sucked by the suction pump  94 , and at the time of ejecting toward the capping member  52 , dispersion of the suction forces at the nozzles does not arise. 
     In the contaminating substance removing process, the capping member  52  is disposed horizontally with respect to the box body  68 . However, when the contaminating substance removing process ends, the stepping motors  58  shown in  FIG. 5  are driven, and as shown in  FIG. 11 , each inkjet recording head  20  moves upward along radial direction of the transporting drum  26  with respect to the head holder  40 , and move away from the capping member  52  (withdrawn height S). Then, the inkjet recording head  20  moves via the head holder  40  in a direction orthogonal to the transporting direction of the recording sheet P. 
     Here, the withdrawn height S is higher than the cleaning height R. When the head holder  40  is slidingly moving, the nozzle surface  22  of the inkjet recording head  20  does not contact the wiper blade  50 . 
     On the other hand, when the inkjet recording head  20  moves from the attached height Q to the withdrawn height S, as shown in  FIG. 9 , the end surface of the inkjet recording head  20  moves away from the push plate  86  of the capping member  52 . 
     Due thereto, the guide pins  84  move via the cam grooves  70 ,  72 ,  74 ,  76  (see  FIG. 6 ) by the urging force of the coil spring  88 , and the capping member  52  tilts with respect to the box body  68 . The ink that has accumulated within the capping member  52  gathers toward the discharge opening  96  side, is sucked through the discharge opening  96  by the suction pump  94 , and is discharged to the waste ink tank  90 . 
     Then, as shown in  FIG. 12 , when the inkjet recording head  20  moves to the position facing the transporting drum  26 , the stepping motors  58  shown in  FIG. 5  are driven, and each inkjet recording head  20  moves downward along radial direction of the transporting drum  26  with respect to the head holder  40  (withdrawn height S→recording height P). 
     In this way, the inkjet recording heads  20  in accordance with the present exemplary embodiment are, as shown in  FIG. 13A , mounted to the head holder  40  with the mounting angles thereof differing from one another along the peripheral direction of the outer peripheral surface of the transporting drum  26 , and can move up and down (approach and move away) along radial directions of the transporting drum  26 . Further, at the time of carrying out maintenance on the inkjet recording heads  20 , the inkjet recording heads  20  are moved in the up and down directions, and are moved close or withdrawn in directions of approaching-and-moving-away from the transporting drum  26  or the capping units  48 . 
     On the other hand, as shown in  FIG. 13B , in a state in which inkjet recording heads  200  are fixed to a head holder  202  with the mounting angles thereof differing from one another, when the head holder  202  is moved in vertical direction, if the position of the head holder  202  is offset in the heightwise direction, the landing positions at which the inks from the inkjet recording heads  200  land are offset greatly on the transporting drum  26 . 
     Because the image quality deteriorates greatly when the landing positions of the inks of the respective colors are offset in this way, a highly-precise height controlling mechanism is needed. Further, each time the height of the inkjet recording heads  200  is changed, there is the need for fine adjustment of the height of the head holder  202  so that the landing positions of the inks of the respective inkjet recording heads  200  match on the recording sample. 
     Namely, by making the inkjet recording heads  200 , that are disposed with the mounting angles thereof differing from one another, vertically move integrally with the head holder  202 , the mounting angles of the inkjet recording heads  200  with respect to the recording sheet P change. Therefore, an error in the heightwise direction of the head holder  202  greatly affects the landing positions of the inks. 
     However, as shown in  FIG. 13A , in accordance with the present exemplary embodiment, the inkjet recording heads  20  move up and down along radial directions of the transporting drum  26 . Therefore, the mounting angles of the inkjet recording heads  20  do not change. 
     Thus, the affections that errors in the heightwise directions of the inkjet recording heads  20  have on the landing positions of the ink are smaller than in a case in which the head holder  202  is moved vertically, and it is difficult for offset of the landing positions of the inks to arise. 
     In the present exemplary embodiment, as described above, the heights of the inkjet recording head  20  shown in  FIG. 3  are the recording height P, the cleaning height R, the attached height Q, and the withdrawn height S. 
     Here, the recording height P is the height at the time when the inkjet recording head  20  ejects ink toward the recording sheet P on the transporting drum  26 . The cleaning height R is the height at the time when the nozzle surface  22  of the inkjet recording head  20  contacts the wiper blade  50  and cleaning is carried out when the inkjet recording head  20  moves horizontally by the head holder  40 . 
     Further, the attached height Q is the height at the time when nozzle surface  22  of the inkjet recording head  20  faces the capping member  52  and attached to the capping member  52  and the ink within the nozzles is removed. The withdrawn height S is the height at which the nozzle surface  22  does not contact the wiper blade  50  when the inkjet recording head  20  moves horizontally by the head holder  40 . 
     The relationships between the recording height P, the cleaning height R, the attached height Q and the withdrawn height S are as follows. 
     The recording height P&lt;the attached height Q&lt;the cleaning height R&lt;the withdrawn height S. 
     By changing the heights of the inkjet recording heads  20  in accordance with the respective processes in this way, there is no need to move the wiper blades  50 , the capping members  52  and the like, and the structure of the inkjet recording device  10  is simple as compared with a case in which mechanisms that move the wiper blades  50  and the capping members  52  are provided. 
     Further, as shown in  FIG. 3 , the inkjet recording head  20  is moved upward from the recording height P to the cleaning height R, and thereafter, as shown in  FIG. 4 , the head holder  40  is moved horizontally and the nozzles surface  22  of the inkjet recording head  20  slidingly rubs the wiper blade  50  such that the cleaning process is carried out. 
     Then, in the state in which the inkjet recording head  20  faces the capping unit  48 , the inkjet recording head  20  is moved downward to the attached height Q (see  FIG. 10 ), and the contaminating substance removing process of the nozzles by the suction pump  94  is carried out. Thereafter, the inkjet recording head  20  is moved upward to the withdrawn height S (see  FIG. 11 ), and the head holder  40  is moved horizontally (see  FIG. 14 ) and the inkjet recording head  20  is moved downward to the recording height P (see  FIG. 12 ). However, it is not absolutely necessary to carry out all of these processes. 
     Further, because each of the inkjet recording heads  20  can be moved up and down independently of the others, the sliding-rubbing of the nozzle surface  22  of the inkjet recording head  20  by the wiper blade  50  can be selected per inkjet recording head  20 . 
     Thus, depending on the inkjet recording head  20 , the contaminating substance removing process may be carried out without carrying out the cleaning process. In this case, that inkjet recording head  20  moves upward from the recording height P shown in  FIG. 12  to the withdrawn height S, and after being moved horizontally by the head holder  40 , is moved downward from the withdrawn height S to the attached height Q as shown in  FIG. 11 . Of course, all of the inkjet recording heads  20  may be made able to move up and down collectively. 
     Further, in the present exemplary embodiment, as shown in  FIG. 3 , the inkjet recording head  20  is moved upward from the recording height P to the cleaning height R, and thereafter, as shown in  FIG. 4 , the head holder  40  is moved horizontally and the cleaning process is carried out by the nozzle surface  22  of the inkjet recording head  20  slidingly-rubbing (being wiped by) the wiper blade  50 . However, first, ink may be made to overflow-out from the nozzles of the inkjet recording head  20  and the ink may be coated on the entire nozzle surface  22  by the wiper blade  50 , and thereafter, the nozzle surface  22  may be wiped by the wiper blade  50 . 
     In the case of using highly-viscous inks, the ink that adheres to the nozzle surface  22  thickens or hardens at an early stage. Therefore, it is difficult to clean the nozzle surface  22  cleanly merely by wiping by the wiper blade  50 . 
     Therefore, by making the ink overflow-out from the nozzles and moving the inkjet recording head  20  to a coating height T and coating the ink on the entire nozzle surface  22  by the wiper blade  50 , the ink that has adhered to the nozzle surface  22  is dissolved. Then, thereafter, by moving the inkjet recording head  20  to the cleaning height R and wiping the nozzle surface  22  by the wiper blade  50 , the nozzle surface  22  can be cleaned cleanly even if the ink is highly viscous. 
     In this case, in addition to the cleaning process, a coating process is added. As shown in  FIG. 15 , the coating height T is added separately from the cleaning height R to the heights of the inkjet recording heads  20 . 
     Here, at the cleaning height R, the amount of contact between the nozzle surface  22  of the inkjet recording head  20  and the wiper blade  50  is about 0.5 to 2 mm (note that this amount of contact differs in accordance with the material of the wiper blade  50  and the like). However, at the coating height T, the amount of contact between the nozzle surface  22  of the inkjet recording head  20  and the wiper blade  50  is around −3 to 0 mm, and, depending on the types of the inks, there is also a case in which the nozzle surface  22  do not contact the wiper blade  50 . 
     Further, by coating the ink on the nozzle surface  22  by the wiper blade  50 , the ink that has adhered to the nozzle surface  22  is dissolved. Therefore, the time until the ink-harden is the reference for the holding time from after the ink is coated on the nozzle surface  22  until the wiping by the wiper blade  50  is started. Thus, for the ink that is generally used at the inkjet recording head  20 , the holding time is preferably about 1 to 300 seconds, although it depends on the types of the inks as well. 
     Because the nozzle surface  22  is wiped by the wiper blade  50  after the ink is coated on the entire nozzle surface  22  once by the wiper blade  50 , the inkjet recording head  20  moves reciprocally with respect to the wiper blade  50 . 
     Thus, after the nozzle surface  22  is wiped by the wiper blade  50 , the inkjet recording head  20  is disposed above the transporting drum  26 . Accordingly, if the contaminating substance removing process is to be carried out thereafter, the inkjet recording head  20  is moved upward (the withdrawn height S), and thereafter, the head holder  40  is moved horizontally. 
     Note that, although the contaminating substance removing process by the capping member  52  is described here, other than this, the ink may be ejected to a region of the transporting drum  26  that is other than the region that the recording sheet P contacts. After the ink is coated on the entire nozzle surface  22  by the wiper blade  50  and the nozzle surface  22  is wiped by the wiper blade  50 , the inkjet recording head  20  is disposed above the transporting drum  26 . Therefore, by causing the ink to be ejected onto the transporting drum  26  as is, further movement of the inkjet recording head  20  can be eliminated. 
     Further, here, the recording sheet P is transported by the transporting drum  26  that serves as a transporting body. However, the present invention is not limited to a rotating body such as the transporting drum  26 . For example, as shown in  FIG. 16 , a structure may be utilized in which a transporting belt  102 , that has recording surfaces  102 Y,  102 M,  102 C,  102 K of angles that differ in accordance with stretching rollers  101  or the like, and inkjet recording heads  104  face one another. In this case, the respective inkjet recording heads  104  are disposed with the mounting angles thereof differing from one another, such that the respective recording surfaces  102 Y,  102 M,  102 C,  102 K of the transporting belt  102  and the nozzle surfaces of the inkjet recording heads  104  face each other. 
     Moreover, the present invention can be applied as well to a structure in which respective inkjet recording heads are disposed parallel to one another with respect to a planar transporting belt, although the affections that errors in the heightwise direction of the inkjet recording heads have on the landing positions of the inks are not as great as compared with cases in which the above-described transporting bodies are used.