Abstract:
An inkjet printer includes a conveyance unit, a recording head, a sealing unit, and a carrier unit. The conveyance unit conveys a recording medium in a conveyance direction. The recording head includes plural recording portions. Each recording portion has plural ejection ports for ejecting ink. The recording portions partially overlap each other if viewed in the conveyance direction, when the recording head is located at a recording position where the recording head performs record with respect to the recording medium. The sealing unit is disposed in a region outside the conveyance unit. The sealing unit includes plural sealing portions each of which seals the ejection ports of each recording portion. The sealing portions are arranged in the conveyance direction. The carrier unit carries the recording head in a carrying direction between a sealing position where each sealing portion faces the ejection ports of each recording portion and the recording position.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to an inkjet printer, and particularly relates to an inkjet printer, which can be miniaturized.  
         [0003]     2. Description of the Related Art  
         [0004]     An inkjet printer having two line-type recording heads obtained by splitting recording heads into a recording head for black ink and a recording head for color inks is known as disclosed in JP-A-2002-59559. The two recording heads of the inkjet printer are formed to be large enough to extend all over the paper width-direction range, and disposed in parallel in the conveyance direction of the paper. Cap members for reducing evaporation of the inks in the recording heads are disposed in parallel to the recording heads in the conveyance direction of a recording medium. The cap members are formed to be large enough to extend all over the paper width-direction range correspondingly to the dimensions of the recording heads, respectively.  
       SUMMARY OF THE INVENTION  
       [0005]     However, in the inkjet printer having two recording heads one of which is a recording head for black ink and the other of which is a recording head for color inks as described above, a plurality of ejections holes for ejecting ink are formed all over the paper width-direction range in each recording head because the recording head is a line-type recording head. Accordingly, the yield rate in the manufacturing process deteriorates because each recording head has a large number of ejection ports corresponding to the paper width. Thus, there is a problem that the manufacturing cost increases. In addition, long cap members corresponding to the long line-type recording heads have to be installed in a region outside the conveyance path of a recording medium. Thus, there is a problem that the apparatus becomes large in scale.  
         [0006]     The invention was developed to solve the foregoing problems and provides an inkjet printer, which can be miniaturized.  
         [0007]     In order to solve the foregoing problems, according to one embodiment of the invention, an inkjet printer includes a conveyance unit, a recording unit, a sealing unit, and a carrier unit. The conveyance unit conveys a recording medium in a conveyance direction. The recording head includes aplurality of recording portions. Each of the recording portions has a plurality of ejection ports for ejecting ink. The recording portions partially over lap each other if viewed in the conveyance direction, when the recording head is located at a recording position where the recording head performs record with respect to the recording medium. The sealing unit is disposed in a region outside the conveyance unit and includes a plurality of sealing portions. Each of the sealing unit seals the ejection ports of each recording portion and which are arranged in the conveyance direction. The carrier unit carries the recording head in a carrying direction between a sealing position where each sealing portion faces the ejection ports of each recording portion and the recording position.  
         [0008]     With the above-described configuration, the plurality of recording portions cover the recording area of the recording medium. Thus, there is an effect that the yield rate in the manufacturing process is improved so that the manufacturing cost can be reduced in comparison with the case where a single recording portion is produced to be large enough to extend over the recording area of the recording medium. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a schematic view schematically showing the configuration of an inkjet printer according to an embodiment of the invention.  
         [0010]      FIG. 2  is a block diagram showing the outline of the electric circuit configuration of the inkjet printer.  
         [0011]      FIG. 3  is a side view taken from Y direction in  FIG. 1 , showing the configuration of inkjet heads and a capping unit.  
         [0012]      FIG. 4  is a top view taken from Z direction in  FIG. 1 , showing the configuration of the inkjet heads and the capping unit located in a recording position.  
         [0013]      FIG. 5  is a section view of the capping unit, taken along line V-V in  FIG. 4 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]     A preferred embodiment of the invention will be described below with reference to the accompanying drawings.  FIG. 1  is a schematic view schematically showing the configuration of an inkjet printer  1  according to an embodiment of the invention. In  FIG. 1 , the inkjet printer  1  chiefly includes a paper feed cassette  10 , a paper feed roller  11 , roller portions  20   a ,  20   b ,  20   c  and  20   d , a conveyance unit  13 , a pressure roller  8 , two inkjet heads  17  and  57 , guide shafts  34   a ,  34   b  and  34   c , and a paper discharge tray  19 . Sheets of paper  12  are stacked in the paper feed cassette  10 . The paper feed roller  11  whose surface is formed out of rubber feeds the paper  12  from the paper feed cassette  10  into the conveyance path of the paper  12 . The paper  12  fed into the conveyance path by the paper feed roller  11  are fed in the conveyance direction of the paper  12  by the roller portions  20   a ,  20   b ,  20   c  and  20   d . The conveyance unit  13  conveys the paper  12 . The pressure roller  8  presses the paper  12  onto the conveyance unit  13 . The inkjet heads  17  and  57  eject various inks onto the paper  12  so as to perform recording (printing). The guide shafts  34   a ,  34   b  and  34   c  function as guides for moving the inkjet heads  17  and  57  forward and backward in the width direction of the paper  12 , that is, X direction in  FIG. 1 . The paper  12  on which desired printing has been performed by the inkjet heads  17  and  57  is discharged to the paper discharge tray  19 .  
         [0015]     The inks to be ejected from the inkjet heads  17  and  57  include four color inks of cyan, magenta, yellow and black. A cyan ink cartridge  4 C, a magenta ink cartridge  4 M, a yellow ink cartridge  4 Y and a black ink cartridge  4 K filled with the color inks respectively are disposed under a capping unit  30  (see  FIG. 3 ), which will be described later.  
         [0016]     In addition, a TF motor  21  (see  FIG. 2 ) functioning as a driving source for moving the inkjet heads  17  and  57  forward and backward in the width direction of the paper  12  (X direction) is disposed between the paper feed cassette  10  and the conveyance unit  13  (see  FIG. 3 ).  
         [0017]     The conveyance unit  13  has a belt  9 , two conveyance rollers  15   a  and  15   b , a support member  14 , and four additional rollers  16   a ,  16   b ,  16   c  and  16   d . The belt  9  is formed out of a material having flexibility without stretch ability, and the outer surface thereof has adhesiveness. The conveyance rollers  15   a  and  15   b  are driven by an LF motor  80  (see  FIG. 2 ) while retaining the belt  9  at its both ends. The support member  14  supports the belt  9  from below when the belt  9  passes through a printing area where the inks are ejected from the inkjet heads  17  and  57  to thereby perform desired printing. The additional rollers  16   a ,  16   b ,  16   c  and  16   d  gives tension to the bent  9  from the inside of the belt  9 .  
         [0018]     A BC motor  82  (see  FIG. 2 ) can drive the support member  14  and the additional rollers  16   a - 16   d  integrally in the up/down direction (that is, Z direction) so as to vary the position of the belt  9  in the up/down direction (Z direction in  FIG. 1 ) . Driving the support member  14  and the additional rollers  16   a - 16   d  in the up/down direction is performed so that they move down when the TF motor  21  reciprocates the inkjet heads  17  and  57  are reciprocated, and they move up when the inkjet heads  17  and  57  are disposed at a predetermined recording position. Incidentally, there is formed a gap of about “1 mm” between each inkjet head  17 ,  57  and the belt  9 . Accordingly, it is also possible to reciprocate the inkjet heads  17  and  57  without operating the support member  14  and the additional rollers  16   a - 16   d  in the up/down direction. Instead, the support member  14  may swing around the conveyance roller  15   b  as a shaft.  
         [0019]     Here, description will be made on a series of operations till the paper  12  fed from the paper feed cassette  10  is discharged to the paper discharge tray  19 .  
         [0020]     The paper feed cassette  10  includes a paper support plate, a compression spring and a paper presser foot. The paper support plate supports, from below, sheets of paper  12  stacked in the paper feed cassette  10 . The compression spring urges the paper support plate upward. The paper presser foot presses the stacked sheets of paper  12  from above so as to prevent the uppermost sheet of paper  12  from slipping away accidentally. The uppermost sheet of paper  12  abuts against the paper feed roller  11  due to the paper support plate, the compression spring and the paper presser foot.  
         [0021]     When the paper feed roller  11  is rotated by a not-shown driving source, the paper  12  is fed out to the conveyance path by the paper feed roller  11 . The paper  12  fed out by the paper feed roller  11  is sent to the roller portion  20   a . The paper  12  put between a pinch roller and a paper feed rubber roller of the roller portion  20   a  is sent to the roller portion  20   b . The roller portion  20   b  has the same configuration as the roller portion  20   a . The paper  12  put between a pinch roller and a paper feed rubber roller of the roller portion  20   b  is fed toward the inkjet heads  17  and  57 .  
         [0022]     The paper  12  fed through the roller portions  20   a  and  20   b  is pressed by the pressure roller  8  immediately before the conveyance unit  13  so as to adhere to the belt  9 . Thus, the paper  12  is prevented from slipping in the printing area. While the paper  12  adhering to the belt  9  passes between the inkjet heads  17  and  57  and the belt  9 , inks are ejected from the inkjet heads  17  and  57  so as to perform desired printing.  
         [0023]     The paper  12  on which desired printing has been performed by the inkjet heads  17  and  57  is finally discharged to the paper discharge tray  19  through the roller portions  20   c  and  20   d  configured in the same manner as the roller portion  20   a . Incidentally, although the embodiment has been described on the case where the four roller portions  20   a - 20   d  are provided in the conveyance path of the paper  12 , not-shown plural roller portions may be provided in addition to the roller portions  20   a - 20   d . In addition, of the plural roller portions provided in the conveyance path, at least one maybe driven by a not-shown driving source so as to convey the paper  12 .  
         [0024]      FIG. 2  is a block diagram showing the outline of the electric circuit configuration of the inkjet printer  1 . A control unit for controlling the inkjet printer  1  includes a main control board  70 , and a sub-control board  71  for controlling the inkjet heads  17  and  57 . The main control board  70  is mounted with a microcomputer (CPU)  72 , a ROM  73 , a RAM  74 , an image memory  77  and a gate array (G/A)  76 . The CPU  72  has a one-chip configuration. The ROM  73  is a read-only memory for storing fixed-value data including various control programs to be executed by the CPU  72 , judgment tables and the like. The RAM  74  is a rewritable memory for temporarily storing various data and the like.  
         [0025]     The CPU  72  functioning as an arithmetic unit executes various processes in accordance with the control programs stored in ROM  73  in advance. In addition, the CPU  72  generates a printing timing signal and a reset signal, and transfers the signals to the G/A  76 , which will be described later. An operation panel  78 , a head carriage motor (TF motor) drive circuit  85 , a belt up/down motor (BC motor) drive circuit  83 , a conveyance motor (LF motor) drive circuit  81 , etc. are connected to the CPU  72 . A user gives instructions for printing and the like through the operation panel  78 . The TF motor drive circuit  85  drives the TF motor  21  for reciprocating the inkjet heads  17  and  57  in the width direction of the paper  12  (X direction) The BC motor drive circuit  83  drives a BC motor  82  for operating the support member  14  and the additional rollers  16   a - 16   d  in the up/down direction (Z direction) so as to change the height of the belt  9 . The LF motor drive circuit  81  operates the LF motor  80  for rotating the conveyance rollers  15   a  and  15   b  to thereby drive and rotate the belt  9  so as to convey the paper  12 . The CPU  72  controls the operation of each device connected thus.  
         [0026]     The G/A  76  outputs print data (driving signal), a transfer clock, a latch signal, a parameter signal and an ejection timing signal in accordance with the printing timing signal transferred from the CPU  72  and image data stored in the image memory  77 . The image data is printed on the recording medium based on the print data. The transfer clock is synchronized with the print data. A reference printing waveform signal is generated from the parameter signal. The ejection timing signal is outputted in a constant period. The G/A  76  transfers those signals to the sub-control board  71  mounted with a head driver.  
         [0027]     In addition, the G/A  76  stores image data into the image memory  77 . The image data is transferred from external equipment such as a computer through an interface (I/F)  79 . The G/A  76  generates a data reception interrupt signal based on data transferred from a host computer or the like through the I/F  79 , and transfers the signal to the CPU  72 . The ROM  73 , the RAM  74  and the G/A  76  are connected to the CPU  72  through a bus line  75 .  
         [0028]     The sub-control board  71  is a board for driving the inkjet heads  17  and  57  by a head driver (drive circuit) mounted on the sub-control board  71 . The head driver is controlled through the G/A  76  mounted on the main control board  70 , so as to apply a drive pulse of waveform corresponding to a recording mode to each drive element of the recording heads. Thus, a predetermined amount of ink is ejected.  
         [0029]     Next, with reference to FIGS.  3  to  5 , description will be made on the configuration of the inkjet heads  17  and  57  and the capping unit  30 , and the configuration in which the inkjet heads  17  and  57  reciprocate between the recording position and the capping unit  30 .  FIG. 3  is a side view taken from the Y direction in  FIG. 1 , showing the configuration of the inkjet heads  17  and  57  and the capping unit  30 .  FIG. 4  is a top view taken from the Z direction in  FIG. 1 , showing the configuration of the inkjet heads  17  and  57  and the capping unit  30  positioned at the recording position.  FIG. 5  is a section view of the capping unit  30 , taken along line V-V in  FIG. 4 .  
         [0030]     The inkjet head  17  has a head for each color. That is, the inkjet head  17  is constituted by a yellow head  17 Y for ejecting yellow ink, a magenta head  17 M for ejecting magenta ink, a cyan head  17 C for ejecting cyan ink, and a black head  17 K for ejecting black ink. Each of these heads is connected to an ink cartridge corresponding to the ink of the head through a tube. When the ink is ejected from the head so that the ink decreases, an amount of ink corresponding to the decrease of the ink is charged from the ink cartridge through the tube.  
         [0031]     Each head is a line-type head. Four actuator units each having a substantially trapezoidal shape in view taken from the Z direction are provided in the head. The actuator units are disposed so that their end portions overlap each other in a direction in which the short sides of the trapezoids are opposed to each other and in the conveyance direction (the Z direction in  FIG. 4 ) of the paper  12 . In the ejection area of the head, a plurality of ejection ports for ejecting ink therefrom are arrayed in the form of a 16-column matrix. Accordingly, printing can be performed without any gap between adjacent ones of the actuator units. In this embodiment,  664  ejection ports are formed all over one ejection area. Incidentally, the inkjet head  57  has the same configuration as the inkjet head  17 , and description thereof will be omitted.  
         [0032]     To perform desired printing on the paper  12 , the inkjet heads  17  and  57  are disposed so that their one end portions overlap each other in the conveyance direction of the paper  12  (the Y direction) as shown in  FIG. 4 . This configuration is adopted to perform printing without any gap between the inkjet heads  17  and  57 . In other words, the actuator units provided on the one end portions of the inkjet heads  17  and  57  overlap each other when viewed in a direction in which the short sides of the trapezoids of the actuator units are opposed to each other.  
         [0033]     The capping unit  30  is used to seal the ejection surfaces of the inkjet heads  17  and  57  having ejection ports formed therein when the inkjet heads  17  and  57  are not in use. Thus, a failure in ejection due to evaporation of ink droplets inside the ejection ports is prevented from occurring, so that the inkjet heads  17  and  57  can be kept in good condition. The capping unit.  30  is disposed adjacently to the conveyance unit  13  in the width direction of the paper  12  (that is, the X direction), and has dimensions corresponding to the inkjet heads  17  and  57 . On the top of the capping unit  30 , cap portions  40 Y,  40 M,  40 C and  40 K for sealing the ejection surfaces are disposed correspondingly to the heads of the inkjet head  17  respectively, and cap portions  41 Y,  41 M,  41 C and  41 K for sealing the ejection surfaces are disposed correspondingly to the heads of the inkjet head  57  respectively.  
         [0034]     Incidentally, as shown in  FIG. 4 , the eight cap portions  40 Y- 40 K and  41 Y- 41 K are integrated in parallel in the conveyance direction of the paper  12  (that is, the Y direction) so as to form a cap body  31  (see  FIG. 3 ).  
         [0035]      FIG. 5A  shows a state where the capping unit  30  is separate from the inkjet head  57 .  FIG. 5B  shows a state where the capping un it  30  seals the inkjet head  57 . Each of the capping unit  30  includes the cap body  31 , a movable member  33 , a cap holder  101 , and the cap portions  41 Y- 41 K ( 40 Y- 40 K). Springs  102  are disposed between the cap body  31  and the cap holder  101  and urge the cap holder  101  upwardly. The cap portions  40 Y- 40 K and  41 Y- 41 K are disposed on the upper surfaces of the cap holders  101 , respectively. The movable member  33  has a cam surface extending in the X direction. It is noted that the movable member  33  (the cam surface) is disposed on the +Y-direction side with respect to the cap portion  41 K in  FIG. 4  and that the movable member  33  (not shown) is also disposed on the −Y-direction side with respect to the cap portion  40 Y. The cam surface of the movable member  33  defines holes  33   a ,  33   b  and holes  33   c ,  33   d ,  33   l , which elongate in the X direction horizontally. As shown in  FIG. 5 , the holes  33   a  and  33   b  have the highest portions in the Z direction on the Xb-direction side while being lower gradually as the position goes in the arrow Xa direction. Shafts  33   h ,  33   i ,  33   k  fixed to a frame (not-shown) of the inkjet printer  1  are inserted into the holes  33   c ,  33   d ,  33   l , respectively. In other words, the shafts  33   h ,  33   i ,  33   k  support the movable member  33 . Spring  33   m  is disposed between the shaft  33   k  and the movable member  33  and urges the movable member  33  in the Xb direction. As shown in  FIG. 5A , when the inkjet heads  17 ,  57  are separate from the capping units  30 , since the spring  33   m  urges the movable member  33  in the left direction (Xb direction), the shafts  33   h ,  33   i ,  33   k  are located at the rightmost position in the holes  33   c ,  33   d ,  33   l . one of the X-direction side surfaces of the movable member  33  on the Xb-direction side includes a pushed portion  33   g , which protrudes therefrom in the Xb direction. The cap body  31  has two Y-direction side surfaces and two X-direction side surfaces, which rise from a bottom surface thereof. Shafts  32   a ,  32   b  protrude from each of the Y-direction side surface of the cap body  31  in the Y direction and are inserted into the holes  33   a ,  33   b  of the movable member  33 , respectively. The cap body  31  also includes a protrusion piece  31   b  that protrudes from the Y-direction side surface of the cap body  31  downwardly and defines a hole  31   c . A shaft  33   j  fixed to the frame of the inkjet printer  1  is inserted into the hole  31   c . The cap holder  101  is supported by the cap body  31  through notches  31   a . Since the notches  31   a  elongate in the vertical direction (Z direction), the cap holder  101  is movable in the Z direction while being urged by the spring  102 . With this configuration, the movable member  33  can reciprocate in the carriage direction of the inkjet heads  17  and  57  (directions of the arrows Xa and Xb in  FIG. 3 ).  
         [0036]     As shown in  FIG. 5 , the inkjet heads  17 ,  57  include a pushing portions  17   x ,  57   x  at end portions thereof in the Xb direction. The pushing portions  17   x ,  57   x  have an L-like shape and protrude in the Xa direction as shown in  FIG. 5 .  
         [0037]     As shown in  FIG. 4 , the TF motor  21  is disposed under the conveyance unit  13  and above the paper feed cassette  10 . A rotating shaft  29  of the TF motor  21  and a drive shaft  23  for reciprocating the inkjet heads  17  and  57  are linked through the belt  22 . The driving force of the TF motor  21  is transmitted to the drive shaft  23  through the belt  22 . The drive shaft  23  is linked with a first clutch  35   a . The first clutch  35   a  is linked with a first belt  65  designed to be rotatable by pulleys  64  and  66 , and also linked with the rotating shaft  36  for transmitting the driving force to a second clutch  35   b . The first clutch  35   a  can change over mechanically as to whether to transmit the driving force to the first belt  65  and the rotating shaft  36  or not.  
         [0038]     The second clutch  35   b  is linked with a second belt  25  designed to be rotatable by pulleys  24  and  26 . The second clutch  35   b  can change over mechanically as to whether to transmit the second belt  25  the driving force transmitted to the rotating shaft  36  to or not.  
         [0039]     The inkjet head  17  is fixed to the second belt  25  through two belt fixing members  28   a  and  28   b . The inkjet head  17  is attached to the guide shaft  34   a  through two guide members  27   a  and  27   b  so that the guide shaft  34   a  guides the inkjet head  17 , and also attached to the guide shaft  34   b  through a guide member  27   c  so that the guide shaft  34   b  guides the inkjet head  17 . Thus, when the second belt  25  is driven, the inkjet head  17  is reciprocated in the width direction of the paper  12  (that is, the X direction) while being guided by the guide shafts  34   a  and  34   b.    
         [0040]     The inkjet head  57  is fixed to the first belt  65  through two belt fixing members  68   a  and  68   b . The inkjet head  57  is attached to the guide shaft  34   c  through two guide members  67   a  and  67   b  so that the guide shaft  34   c  guides the inkjet head  57 , and also attached to the guide shaft  34   b  through a guide member  67   c  so that the guide shaft  34   b  guides the inkjet head  57 . Thus, when the first belt  65  is driven, the inkjet head  57  is reciprocated in the width direction of the paper  12  (that is, the X direction) while being guided by the guide shafts  34   b  and  34   c.    
         [0041]     When the ejection ports of the inkjet heads  17  and  57  are to be sealed with the capping unit  30 , the first clutch  35   a  is changed over to be able to transmit the driving force, while the second clutch  35   b  is changed over not to transmit the driving force. Then, the TF motor  21  is driven. Incidentally, before the TF motor  21  is driven, the support member  14  and the additional rollers  16   a - 16   d  are moved down to surely prevent interference from occurring between the inkjet heads  17  and  57  and the belt  9 , as described above.  
         [0042]     Next, description will be made on the operation for sealing the heads  17  and  57 . When the TF motor  21  is driven with the heads  17  and  57  being located in the recording position shown in  FIG. 4 , the inkjet head  57  begins to be carried toward the capping unit  30  (in the arrow Xa direction in  FIG. 3 ). When the inkjet head  57  reaches a position where the inkjet head  57  is aligned with the inkjet head  17  in the conveyance direction of the paper  12  (that is, the Y direction), the second clutch  35   b  is changed over to be able to transmit the driving force so as to carry the inkjet heads  17  and  57  integrally toward the capping unit  30 .  
         [0043]     The inkjet heads  17  and  57  are carried toward the capping unit  30 , and the pushing portion  57   x  of the inkjet head  57  abuts against the pushed portion  33   g  of the movable member  33 . When the pushing portion  57   x  of the inkjet head  57  further pushes the pushed portion  33   g  of the movable member  33  so that the movable member  33  moves in the arrow Xa direction against the urging force of the spring  33   m , the holes  33   a  and  33   b  of the movable member  33  press upward the shafts  32   a  and  32   b  projecting from the Y-direction side surface of the cap body  31 . The shafts  32   a  and  32   b  are guided by the holes  33   a ,  33   b  so as to move upward gradually. When the shafts  32   a ,  32   b  are moved upward together with the cap body  31 , the cap holder  101  is move upward. As a result, the cap portions  40 Y- 40 K and  41 Y- 41 K move upward to seal the ink ejection surface of the inkjet head  17 ,  57 .  
         [0044]     On the other hand, when recording is resumed, the inkjet heads  17  and  57  are moved in the arrow xb direction so as to return to the recording position. When the pressing portions  17   x ,  57   x  of the inkjet heads  17 ,  57  detach from the pressed portion  33   g  of the movable member  33 , the movable member  33  also moves in the arrow Xb direction due to the urging force of the spring  33   m , so that the holes  33   a  and  33   b  of the movable member  33  presses downward the shafts  32   a  and  32   b  of the cap body  31 . The shafts  32   a  and  32   b  are guided by the holes  33   a  and  33   b  so as to move downward gradually. Then, the cap body  31  moves downward to retract. As a result, the cap portions  40 Y- 40 K and  41 Y- 41 K detach from the ink ejection surfaces of the inkjet heads  17 ,  57 .  
         [0045]     The inkjet heads  17  and  57  are carried to the recording position as follows. That is, at the timing when the inkjet head  17  has been carried to the recording position, the second clutch  35   b  is changed over not to transmit the driving force. Then, the carriage of the inkjet head  17  is completed. At the timing when the inkjet head  57  has been carried to the recording position, the first clutch  35   a  is changed over not to transmit the driving force. After that, driving the TF motor  21  is stopped. Then, the carriage of the inkjet head  57  is completed. When the inkjet heads  17  and  57  are disposed at the recording position, the support member  14  and the additional rollers  16   a - 16   d  are lifted up.  
         [0046]     Accordingly, the recording heads  17  and  57  can be carried independently of each other between a sealing position where the cap unit  30  seals the recording heads  17  and  57  and a recording position where the recording heads  17  and  57  eject ink onto the paper  12 . Therefore, the positional relationship among the recording heads  17  and  57  when they are located at the recording position, can be changed from that when they are located at the sealing position. The positional relationship among the recording heads  17  and  57  at the sealing position can be set suitably independently of that at the recording position, so that the inkjet printer  1  can be miniaturized and aggregated in comparison with that in the background art.  
         [0047]     In addition, a single motor (TF motor  21 ) generates drive power and can transmit the drive power to the recording heads  17  and  57  independently. Therefore, this embodiment does not need a plurality of TF motors  21 . As a result, the manufacturing cost of the inkjet printer  1  can be reduced.  
         [0048]     In addition, this embodiment does no need a drive source for moving the cap unit  30  toward the recording heads  17  and  57  after the recording heads  17  and  57  are carried a position where the recording heads  17  and  57  face the cap unit  30 . Thus, the manufacturing cost can also be reduced.  
         [0049]     As described above, the inkjet printer  1  has the line-type inkjet heads  17  and  57  separated in the width direction of the paper  12  (the X direction) and disposed so that portions thereof overlap each other in the conveyance direction of the paper  12  (the Y direction). Accordingly, in comparison with the case where one inkjet head is produced to be large enough to extend all over the width-direction range of the paper  12 , the yield rate in the manufacturing process can be improved so that the manufacturing cost can be reduced.  
         [0050]     In addition, the capping unit  30  is disposed adjacently to the conveyance unit  13 , and the cap portions disposed on the top of the capping unit  30  are arrayed in parallel in the conveyance direction of the paper  12 . Accordingly, the inkjet heads  17  and  57  separated in the width direction of the paper  12  (the X direction) and disposed so that portions thereof overlap each other in the conveyance direction of the paper  12  (the Y direction) can be disposed in parallel above the capping unit  30 . As a result, the inkjet printer  1  can be prevented from increasing in size in the conveyance direction of the paper  12  (the Y direction), and prevented from increasing in size in the width direction of the paper  12  (the X direction). It is therefore possible to prevent the apparatus from increasing in size.  
         [0051]     Although the invention has been described above based on its embodiment, the invention is not limited to the aforementioned embodiment at all. It can be imagined easily that various improvements and modifications can be made without departing from the gist of the invention.  
         [0052]     For example, although the embodiment has been described on the case where the first clutch  35   a  is provided so as to be changed over whether to transmit the driving force to the first belt  65  and the rotating shaft  36  or not, the rotating shaft  23  may be linked to the first belt  65  and the rotating shaft  36  without providing the first clutch  35   a . In this case, driving the first belt  65  can be controlled by the rotation and stop of the TF motor  21 , and driving the second belt  25  can be controlled by changing over the second clutch  35   b . Thus, the number of parts can be reduced so that the manufacturing cost can be reduced.  
         [0053]     Although the embodiment has been described on the case where the two inkjet heads  17  and  57  are sealed simultaneously when the ejection surfaces of the inkjet heads  17  and  57  are sealed with the capping unit  30 , one of the inkjet heads not to be used may be sealed with the capping unit  30 . For example, when the size of the paper  12  is so small that printing can be performed by only the inkjet head  17 , only the inkjet head  57  may be sealed with the capping unit  30  in order to prevent evaporation from the ejection ports of the inkjet head  57 . In this case, when two guide shafts serving as the guide shaft  34   b  are provided for the inkjet head  17  and for the inkjet head  57  respectively, the inkjet head  57  alone can be carried. Alternatively, when the size of the paper  12  is so small the printing can be performed by only the inkjet head  57 , only the inkjet head  17  may be sealed with the capping unit  30 . With this alternative configuration, there is no need to provide two guide shafts  34   b.    
         [0054]     Although the embodiment has been described on the case where the inkjet head is separated into the two inkjet heads  17  and  57 , the inkjet head may be separated into three or more plural inkjet heads. On this occasion, the separated heads are disposed so that each of the separated heads located on the both sides in the width direction of the paper (the X direction) overlaps another separated head adjacent thereto in one end portion thereof, while the other separated heads that are not located on the both sides over lap two other separated heads adjacent thereto on the both end portions thereof.