Patent Publication Number: US-8523348-B2

Title: Image recording apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority from Japanese Patent Application No. 2010-150547 filed on Jun. 30, 2010, the disclosure of which is herein incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an image recording apparatus for recording an image onto a recording medium by ejecting liquid onto the recording medium, and more particularly to such an image reading apparatus that is capable of restraining an amount of consumption of the liquid without deteriorating quality of the recorded image. 
     There is known an inkjet printer having a plurality of inkjet heads and a conveyor belt. The inkjet heads are arranged in a conveyance direction in which a recording medium is to be conveyed, and have respective ejection surfaces through which ink is to be ejected onto the recording medium. The conveyor belt is configured to convey the recording medium, such that the recording medium is opposed to the respective ejection surfaces when the recording medium is positioned in respective positions corresponding to the respective ejection surfaces. The inkjet printer further has a maintenance unit for performing a maintenance operation onto the inkjet heads. The maintenance unit includes a tray configured to receive the ink and a wiper configured to wipe the ejection surfaces. When the maintenance operation is to be performed onto one of the inkjet heads, the inkjet heads are moved in such a direction that causes the ejection surfaces of the inkjet heads to be moved away from the conveyor belt, and then the tray is positioned in a position between the conveyor belt and the ejection surfaces of the respective inkjet heads, so as to be opposed to the ejection surfaces of the respective inkjet heads. In the maintenance operation, the ink is ejected from the inkjet heads into the tray, and then the ejection surfaces are wiped by the wiper whereby the ink adhering to the ejection surfaces is removed by the wiper. 
     SUMMARY OF THE INVENTION 
     In the above-described inkjet printer, there is a case (such as recording of a monochrome image) where an image is recorded on a recording medium while at least one of the recording heads is not ejecting ink, i.e., while at least one of the recording heads is not participating in the recording. Even in such a case, the recording medium is caused to pass a position opposed to the at least one of the recording heads that does not participate in the recording, so that foreign substances such as paper dust flutter also around the recording head or heads that do not participate in the recording. Since the foreign substances are likely to adhere to also the recording head or heads not participating in the recording, a maintenance operation has to be performed onto all the inkjet heads, thereby causing a problem that it is not possible to save an amount of ink that is be consumed in the maintenance operation. 
     The above problem might be solved by an image recording apparatus having first, second and third conveyors and first and second recording heads. The first conveyor is configured to convey a recording medium, and the first recording head is configured to eject liquid toward the recording medium that is being conveyed by the first conveyor. The second conveyor is configured to further convey the recording medium conveyed by the first conveyor, and the second recording head is configured to eject liquid toward the recording medium that is being conveyed by the second conveyor. The third conveyor is configured to further convey the recording medium conveyed by the first conveyor, such that the recording medium is conveyed along a conveyance path that is other than a conveyance path defined by the second conveyor. In this image recording apparatus, a flapper is provided to change the conveyance direction of the recording medium, so as to guide the recording medium toward a selected one of the second and third conveyors. The flapper is pivotable to take a selected one of first and second postures. The flapper takes the first posture when the recording medium is to be guided from the first conveyor toward the second conveyor, and takes the second posture when the recording medium is to be guided from the first conveyor toward the third conveyor. In this image recording apparatus, when being conveyed by the third conveyor, the recording medium does not pass a position opposed to the second recording head so that there is no risk that foreign substances adhere onto the ejection surface of the second recording head that does not eject the liquid and does not participate in the recording. Therefore, as long as the recording medium is conveyed by the third conveyor, there is no need to perform a maintenance operation onto the second recording head, thereby making it possible to reduce the amount of consumption of the liquid by the second recording head. 
     However, this image recording apparatus suffers from a problem due to an arrangement in which the third conveyor is configured to convey the recording medium along the conveyance path that is other than the conveyance path defined by the second conveyor so that the third conveyor is disposed in a position other than a position of the second conveyor. That is, the problem is that a conveyance path interconnecting the first and second conveyors or a conveyance path interconnecting the first and third conveyors has to be curved or bent. When the recording medium is to be conveyed through the bent path, the conveyance direction of the recording medium is changed by the flapper. Described specifically, the recording medium which is conveyed along the bent path is, when reaching the flapper, caused to collide at its leading end portion with the flapper, whereby the conveyance direction is abruptly changed. When the conveyance direction is thus changed, a resistance is applied to the recording medium upon collision of the leasing end portion with the flapper. This resistance, which may be referred to as “convey resistance”, is a force applied to the recording medium and acting in a direction opposite to the conveyance direction, and is increased when the leading end portion of the recording medium enters into the bent path. Upon increase of the convey resistance, a velocity of the conveyed recording medium is momentarily reduced. Therefore, if the recording is continued by the first recording head onto the recording medium at the moment of change of the conveyance velocity, there is a risk that the recorded image would be disordered. 
     The present invention was made in view of such a background. It is therefore an object of the invention to provide an image recording apparatus in which it is possible to restrain amount of consumption of liquid and to restrain reduction of quality of recorded image by restraining momentary change of velocity of conveyed recording medium. 
     The above object of the invention may be achieved according to a principle of the invention, which provides an image recording apparatus including: (a) a first conveyor configured to convey a recording medium in a first conveyance direction along a first conveyance path which is defined by said first conveyor; (b) a first recording head configured to eject liquid toward the recording medium that is being conveyed by said first conveyor; (c) a second conveyor configured to convey the recording medium conveyed by said first conveyor, in a second conveyance direction along a second conveyance path which is defined by said second conveyor; (d) a second recording head configured to eject liquid toward the recording medium that is being conveyed by said second conveyor; (e) a third conveyor configured to convey the recording medium conveyed by said first conveyor, in a third conveyance direction along a third conveyance path which is defined by said third conveyor and which is other than the second conveyance path; and (f) a posture changer configured to change a posture of at least a downstream-side portion (as viewed in the first conveyance direction) of said first conveyor whereby said at least said downstream-side portion of said first conveyor is caused to take a selected one of a plurality of angular postures including a first angular posture and a second angular posture, such that at least a downstream-side part (as viewed in the first conveyance direction) of the first conveyance path defined by said at least said downstream-side portion of said first conveyor is directed to the second conveyance path when said at least said downstream-side portion of said first conveyor takes the first angular posture, and such that said at least the downstream-side part of the first conveyance path is directed to the third conveyance path when said at least said downstream-side portion of said first conveyor takes the second angular posture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features, advantages and technical and industrial significance of the present invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings, in which: 
         FIG. 1  is a schematic side view of an internal construction of an inkjet printer  1  according to a first embodiment of the invention, showing a state in which a first conveyor  7  takes a first angular posture; 
         FIG. 2  is a schematic side view of the internal construction of the inkjet printer  1 , showing a state in which the first conveyor  7  takes a second angular posture; 
         FIG. 3  is a perspective view of the internal construction of the inkjet printer  1 ; 
         FIG. 4  is a perspective view of the internal construction of the inkjet printer  1 , showing the first conveyor  7 , a first recording head  9  and a posture changer  21 , with a front-side one of plates constituting a main frame  4  being cut away for clarity; 
         FIG. 5  is a partially cross-sectional view of a first supporter  93  of the inkjet printer  1 , as seen from a left side of the first supporter  93 ; 
         FIG. 6  is a schematic side view of an internal construction of an inkjet printer  201  according to a second embodiment of the invention, showing a state in which a belt conveyor unit  204  takes a first angular posture; and 
         FIG. 7  is a schematic side view of the internal construction of the inkjet printer  201 , showing a state in which the belt conveyor unit  204  takes a second angular posture. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     There will be described preferred embodiments of the present invention, with reference to the drawings. It is noted that, in the following description, there will be used terms “upper”, “lower”, “right”, “left”, “front” and “rear” directions of an inkjet printer  1  which are directions as seen in  FIG. 1 , and which are indicated by respective arrows “UP”, “DOWN”, “RIGHT”, “LEFT”, “FRONT” and “REAR” in all the drawings. 
     [First Embodiment] 
     As shown in  FIG. 1 , the inkjet printer  1  constructed according to the first embodiment of the invention has a generally rectangular-parallelepiped-shaped housing body  2  including an upper portion that serves as a sheet exit tray  3 . Within the housing body  2 , there are disposed a sheet supplier  5 , a first conveyor  7 , a first recording head  9 , a second conveyor  11 , a set of second recording heads  13 , a third conveyor  15 , a sheet discharger  17  and a return conveyor  19 . Within the housing body  2 , there are further disposed a first supporter  93  (see  FIG. 4 ), a posture changer  21  (see  FIG. 4 ), a second supporter  119  (see  FIG. 3 ) and a controller  100 . 
     There will be described components constituting the inkjet printer  1 . The sheet supplier  5  is configured to supply a recording sheet as a recording medium to the first conveyor  7 . The first conveyor  7  is configured to convey the sheet that has been supplied by the sheet supplier  5 , in a first conveyance direction along a first conveyance path defined by the first conveyor  7 . The first recording head  9  is configured to eject ink toward the sheet that is being conveyed by the first conveyor  7 . The second conveyor  11  is configured to further convey the sheet conveyed by the first conveyor  7 , in a second conveyance direction along a second conveyance path defined by the second conveyor  11 . The second recording heads  13  are configured to eject inks toward the sheet that is being conveyed by the second conveyor  11 . The third conveyor  15  is configured to further convey the sheet conveyed by the first conveyor  7 , in a third conveyance direction along a third conveyance path which is defined by the third conveyor  15  and which is other than the second conveyance path. The sheet discharger  17  is configured to discharge the sheet conveyed by the second conveyor  11  or third conveyor  15 , toward the sheet exit tray  3 . The return conveyor  19  is configured to convey or return the sheet (conveyed by the sheet discharger  17  in an opposite direction opposite to a discharging direction) to the first conveyor  7 . The first supporter  93  is provided to support the first conveyor  7  and the first recording head  9  (see  FIG. 4 ). The posture changer  21  is configured to change an angular postures of the first conveyor  7  and the first recording head  9 , by causing the first supporter  93  to be pivoted (see  FIG. 4 ). The second supporter  119  is provided to support the second conveyor  11  and the second recording heads  13  (see  FIG. 3 ). The controller  100  is configured to control activations of some of the these components, i.e., the sheet supplier  5 , first conveyor  7 , first recording head  9 , second conveyor  11 , second recording heads  13 , third conveyor  15 , sheet discharger  17 , return conveyor  19  and posture changer  21 . Each of these components of the inkjet printer  1  will be described below in detail. 
     &lt;Main Frame  4 &gt; 
     As shown in  FIG. 3 , a main frame  4  is disposed within the housing body  2 . The main frame  4  is constituted by a pair of plates consisting of a front-side plate and a rear-side plate. The main frame  4  supports the above-described components, i.e., the sheet supplier  5 , first conveyor  7 , first recording head  9 , second conveyor  11 , second recording heads  13 , third conveyor  15 , sheet discharger  17 , return conveyor  19 , first supporter  93 , posture changer  21  and second supporter  119 . Each of the plates of the main frame  4  has a through-hole  94  in which a shaft of a belt pulley  33  is to be introduced. Each of the plates of the main frame  4  further has through-holes (not shown) in which shafts of respective belt pulleys  55 ,  57  are introduced. The front-side plate of the main frame  4  is provided with a support plate  109  to which a biasing or forcing portion  101  is attached. The support plate  109  is formed integrally with the front-side plate of the main frame  4 , and protrudes rearwardly from the front-side plate. 
     &lt;Sheet Supplier  5 &gt; 
     As shown in  FIG. 1 , the sheet supplier  5  includes a sheet supplying cassette  23 , a sheet supplying roller  27 , a conveying guide  29  and a pair of conveying rollers  31 . 
     The sheet supplying cassette  23  is removably disposed in a lower portion of the housing body  2 , and is capable of accommodating a plurality of sheets stacked therein. The sheet supplying cassette  23  has a box-like shape, and opens upwardly. 
     The sheet supplying roller  27  is disposed in an upper portion of the sheet supplying cassette  23 , and is rotatably held by the main frame  4 . The sheet supplying roller  27  is arranged to be in contact with an uppermost one of the sheets accommodated in the sheet supplying cassette  23 . The sheet supplying roller  27  is to be rotated by a motor (not shown) when the motor receives, from the controller  100 , a command requesting of rotation of the sheet supplying roller  27 . With rotation of the sheet supplying roller  27  that is contact with the uppermost sheet, the uppermost sheet is supplied to the conveying guide  29 . 
     The conveying guide  29  is fixed to the main frame  4 , and is disposed on an upper-left side of the sheet supplying cassette  23 . The conveying guide  29  extends curvedly from the cassette  23  in an upward direction, so as to guide the sheet supplied from the sheet supplying cassette  23 , upwardly toward the first conveyor  7 . 
     The pair of conveying rollers  31  are disposed on halfway of the conveying guide  29 , and are rotatably held by the main frame  4 . One of the conveying rollers  31  is a drive roller that is to be rotated by a motor (not shown) when the motor receives, from the controller  100 , a command requesting rotation of the drive roller. The other of the conveying rollers  31  is a driven roller that is to be rotated together with rotation of the drive roller. The pair of conveying rollers  31  serve to convey the sheet that is being guided by the conveying guide  29 , toward the first conveyor  7 . 
     &lt;First Supporter  93 &gt; 
     As shown in  FIG. 4 , the first supporter  93  supports the first conveyor  7  and the first recording head  9 . Although  FIG. 4  is a perspective view with the front-side plate of the main frame  4  being cut away, the support plate  109  integrally formed with the front-side plate of the main frame  4  is shown for easier understanding. 
     As shown in  FIG. 3 , the first supporter  93  is pivotably held by the main frame  4 . Described specifically, the first supporter  93  is held by the main frame  4  via the belt pulley  33 , and is pivotable about an axis of the belt pulley  33  by the posture changer  21 . With pivot motion of the first supporter  93 , the angular postures of the first conveyor  7  and the first recording head  9  is changed. As shown in  FIG. 4 , the first supporter  93  has a set of walls  97  and a contact portion  99 . The set of walls  97  consist of four walls  103 ,  104 ,  105 ,  106 . 
     The walls  103 ,  104  are plate-like members disposed in rear and front portions of the first supporter  93 , respectively, and is located inside the pair of plates of the main frame  4 . The belt conveyor unit  6  and the first recording head  9  are located between the walls  103 ,  104 , and are sandwiched by the walls  103 ,  104  from the rear and front sides. 
     Each of the walls  103 ,  104  has the through-holes  120 ,  121  in which the shafts of the respective belt pulleys  33 ,  35  are introduced. The shaft of the belt pulley  33  is introduced in the through-holes  120  of the walls  103 ,  104  and the through-holes  94  of the main frame  4 , so that the first supporter  93  is pivotable about the axis of the belt pulley  33 . 
     As shown in  FIG. 5 , supporting projections  107 ,  108  are provided in the respective walls  103 ,  104 , and project inwardly from the respective walls  103 ,  104 . The supporting projections  107 ,  108  cooperate to support the first recording head  9 . 
     The wall  104 , which is disposed in the front portion of the first supporter  93 , is provided with the contact portion  99 . The contact portion  99  projects forwardly from a lower end portion of the wall  104 , and has a lower surface  102 , as shown in  FIG. 5 . The lower surface  102  of the contact portion  99  is in contact with an upper surface (i.e., an upper portion of a circumferential cam surface) of a eccentric cam  111 . With rotation of the eccentric cam  111 , the contact portion  99  is displaced upwardly or downwardly, whereby the first supporter  93  is pivoted. 
     The walls  105 ,  106  are plate-like members extending and interconnecting the walls  103 ,  104 . The first recording head  9  is sandwiched by the walls  105 ,  106  from the left and right sides. 
     &lt;First Conveyor  7 &gt; 
     As shown in  FIGS. 1 and 2 , the first conveyor  7  is configured to convey the sheet that has been supplied by the sheet supplier  5 , in a rightward direction. The first conveyor  7  is constituted by the single belt-conveyor unit  6  which has, in addition to the above-described belt pulleys  33 ,  35 , a conveyor belt  37 , a platen  40 , a pressing roller  39  and a first charge roller  41 . The belt conveyor unit  6  except the first charge roller  41  is fixed to the first supporter  93 . The angular posture of the belt conveyor unit  6  is changed as a result of pivot motion of the first supporter  93 , so that the first conveyor  7  takes a selected one of a plurality of angular postures including a first angular posture shown in  FIG. 1  and a second angular posture shown in  FIG. 2 . 
     As shown in  FIG. 1 , the belt pulleys  33 ,  35  are arranged in a right-left direction, and extend in a front-rear direction. The belt pulley  33 , which is a left-side one of the belt pulleys  33 ,  35 , is a drive pulley that is to be rotated by a motor (not shown) when the motor receives, from the controller  100 , a command requesting of rotation of the belt pulley  33 . The belt pulley  35 , which is a right-side one of the belt pulleys  33 ,  35 , is a driven pulley. That is, the driven pulley is provided by an upstream-side one, as viewed in the first conveyance direction, of the belt pulleys  33 ,  35 . The shaft of the belt pulley  33  is connected to ground. The belt pulley  33  is rotated by a driving force of the motor, in clockwise direction as seen in  FIG. 1 . The belt pulley  35  is rotated by rotation of the belt pulley  33  which is transmitted thereto via the conveyor belt  37 , in the clockwise direction as seen in  FIG. 1 . 
     As shown in  FIG. 4 , the shaft of the belt pulley  33  is rotatably introduced in the through-holes  120  that are formed in the walls  103 ,  104  of the first supporter  93 . The shaft of the belt pulley  33  is rotatably introduced in the through-hole  94  that is formed in the main frame  4 . Meanwhile, the shaft of the belt pulley  35  is rotatably introduced in the through-holes  121  that are formed in the walls  103 ,  104  of the first supporter  93 . 
     The conveyor belt  37  is an endless belt that is stretched around the two belt pulleys  33 ,  35 . When the belt pulley  33  is rotated by the driving force of the motor in the clockwise direction as seen in  FIG. 1 , an upper-side surface of the conveyor belt  37 , which is opposed to the first recording head  9 , is caused to run in the rightward direction as seen in  FIG. 1 . This upper-side surface is provided by an upper portion of the outer circumferential surface of the conveyor belt  37 , and constitutes a supporting surface  38  defines the first conveyance path along which the sheet is to be conveyed by the first conveyor  7 . That is, the supporting surface  38  supports the sheet held thereon, and the conveyor belt  37  is circulated for thereby conveying the sheet in the rightward direction. 
     The platen  40  is fixed to the first supporter  93 , and is disposed to be in contact with an upper portion of an inner circumferential surface of the conveyor belt  37 , so as to support the conveyor belt  37 . Owing to the platen  40 , the supporting surface  38  of the conveyor belt  37  keeps a flat shape. 
     The pressing roller  39  is disposed on an upper side of the belt pulley  33 , and is held in contact with the outer circumferential surface of the conveyor belt  37 . The pressing roller  39  serves to press the sheet (that has been guided by the conveying guide  29 ) down onto the conveyor belt  37 . A sheet sensor  44  is disposed on a downstream side, as viewed in the conveyance direction, of the pressing roller  39 . The sheet sensor  44  is configured to detect the sheet that is conveyed by the conveyor belt  37 , and supplies, to the controller  100 , a signal indicative of detection of the sheet. The pressing roller  39  and the sheet sensor  44  are supported by the first supporter  93 . 
     The first charge roller  41  is disposed on a left side of the belt pulley  33 , and is held in contact with the outer circumferential surface of the conveyor belt  37 . The first charge roller  41  is rotatably held by the main frame  4 . The first charge roller  41  includes a shaft (about which the first charge roller  41  is to be rotated) that is made of a metallic material, and an outer peripheral portion that is made of an elastic material having insulating properties or semi-conducting properties. The shaft of the first charge roller  41  is connected to a positive pole of a first direct-current source  43  that is to be activated when the source  43  receives, from the controller  100 , a command requesting of activation of the source  43 . A negative pole of the source  43  is connected to ground. It is noted that the first charge roller  41  may be supported by the first supporter  93 . 
     When a predetermined level of electric voltage is applied to the shaft of the first direct-current source  43 , an electrical discharge is generated between the first charge roller  41  and the conveyor belt  37 . By the electrical discharge from the first charge roller  41 , the conveyor belt  37  is charged with a positive charge. When the sheet is guided by the conveying guide  29  to the conveyor belt  37 , the sheet is pressed, by the pressing roller  30 , onto the conveyor belt  37 . Since the conveyor belt  37  is charged with the positive charge as a result of the electrical discharge from the first charge roller  41 , a surface of the sheet, which is held in contact with the conveyor belt  37 , is charged with a negative charge, so that the sheet is attracted onto the conveyor belt  37 . Thus, by circulating the conveyor belt  37  onto which the sheet is attracted, the sheet is conveyed along the first conveyance path that is defined by the supporting surface  38  of the conveyor belt  37 , in the rightward direction as seen in  FIG. 1 . In the present embodiment, the belt pulley  33 , first charge roller  41  and first direct-current source  43  cooperate to constitute an attraction generating device that is configured to cause the sheet to be attracted to the conveyor belt  37 . 
     As described above, the belt conveyor unit  6  (constituting the first conveyor  7 ) except the first charge roller  41  is supported by the first supporter  93 . The first supporter  93  is held by the main frame  4  via the belt pulley  33 , and is pivotable about the axis of the belt pulley  33 . By pivot motion of the first supporter  93 , the posture of the first conveyor  7  is changed between the first angular posture and the second angular posture. When the first conveyor  7  takes the first angular posture as shown in  FIG. 1 , the belt pulley  35  is positioned in the same height position as the belt pulley  33 , and the supporting surface  38  of the conveyor belt  37  is parallel to a horizontal plane. Thus, the sheet conveyed by the conveyor belt  37  is moved along the horizontal plane in the rightward direction. On the other hand, when the first conveyance path takes the second angular posture as shown in  FIG. 2 , the belt pulley  35  is positioned in a position lower than the belt pulley  33 , and the supporting surface  38  of the conveyor belt  37  is inclined with respect to a horizontal plane, in a right downward direction. Thus, the sheet conveyed by the conveyor belt  37  is moved in the right downward direction. 
     &lt;First Recording Head  9 &gt; 
     The first recording head  9  is to be activated, when the first recording head  9  receives, from the controller  100 , a command requesting of activation of the head  9 , for thereby ejecting ink toward the sheet that is being conveyed by the first conveyor  7 . The first recording head  9  is a black recording head that is configured to eject black ink toward the sheet. The first recording head  9  is a generally rectangular-parallelepiped-shaped head, as shown in  FIG. 3 , and is configured to eject the black ink having supplied from a black ink tank (not shown) storing the black ink, toward the sheet through a plurality of nozzles that open in a nozzle opening surface (i.e., ejection surface)  45  of the head  9 . As shown in  FIG. 1 , the nozzle opening surface  45  constitutes a bottom surface of the head  9 . 
     The first recording head  9  is supported by the first supporter  93  such that the nozzle opening surface  45  of the head  9  and the supporting surface  38  of the conveyor belt  37  are opposed to each other with a predetermined distance therebetween. Specifically, as shown in  FIG. 5 , the first recording head  9  has a front surface  47  and a rear surface  49 , and the front and rear surfaces  47 ,  49  have first projecting portions  51 ,  53 , respectively, which extend outwardly. The first projecting portions  51 ,  53  are fixed to the above-described supporting projections  107 ,  108  of the first supporter  93 , respectively, whereby the first recording head  9  is supported by the first supporter  93 . 
     An angular posture of the first recording head  9  is changed by pivot motion of the first supporter  93 , namely, the first recording head  9  is pivoted together with the pivot motion of the first supporter  93 , such that a distance between the nozzle opening surface  45  of the first recording head  9  and the supporting surface  38  of the conveyor belt  37  is held constant irrespective of change of the angular posture of the first conveyor  7 . Specifically, when the first conveyor  7  takes the first angular posture, as shown in  FIG. 1 , the nozzle opening surface  45  of the first recording head  9  is parallel to a horizontal plane, namely, parallel to the supporting surface  38  of the conveyor belt  37 . On the other hand, when the first conveyor  7  takes the second angular posture, the nozzle opening surface  45  of the first recording head  9  is inclined with respect to a horizontal plane, in a right downward direction, so as to be parallel to the supporting surface  38  of the conveyor belt  37 . Thus, irrespective of change of the angular posture of the first conveyor  7 , the nozzle opening surface  45  and the supporting surface  38  are distant from each other by a predetermined distance that can be held constant so that an image recording by the first recording head  9  can be carried out with stability. The predetermined distance is a distance which is suitable for carrying out the image recording, namely, a distance which is suitable for avoiding a recorded surface of the sheet from being brought into contact with the nozzle opening surface  45  and which is suitable for enabling ink droplets to be accurately placed in desired positions. 
     &lt;Second Supporter  119 &gt; 
     As shown in  FIG. 3 , the second supporter  119  supports the second conveyor  11  and the set of second recording heads  13 . 
     The second supporter  119  is fixed to the main frame  4 . Like the first supporter  93 , the second supporter  119  has a set of walls which are provided by plate-like members. The set of walls of the second supporter  119  consist of four walls  122 ,  123 ,  124 ,  125 . 
     The walls  122 ,  123  are disposed between the front-side plate and rear-side plate of the main frame  4 . The belt conveyor unit  12  (see  FIG. 1 ) and the second recording heads  13  are located between the walls  122 ,  123 , and are sandwiched by the walls  122 ,  123  from the rear and front sides. 
     Each of the walls  122 ,  123  has through-holes (not shown) in which shafts of the respective belt pulleys  55 ,  57  are introduced. The shaft of the respective belt pulleys  55 ,  57  are rotatably introduced in the through-holes (not shown) of the walls  122 ,  123  and through-holes (not shown) of the main frame  4 . 
     Like in the above-described walls  103 ,  104 , supporting projections (not shown) are provided in the respective walls  122 ,  123 , and project inwardly from the respective walls  122 ,  123 . The supporting projections cooperate to support the set of second recording heads  13 . 
     The walls  124 ,  125  are plate-like members extending and interconnecting the walls  122 ,  123 . The second recording heads  13  are sandwiched by the walls  124 ,  125  from the left and right sides. 
     &lt;Second Conveyor  11 &gt; 
     The second conveyor  11  is configured to convey the sheet (conveyed by the first conveyor  7  when the first conveyor  7  takes the first angular posture) further in the rightward direction as seen in  FIG. 1 . The sheet, which is conveyed by the first conveyor  7  and the second conveyor  11 , is moved along bold arrows (black arrows) in  FIG. 1 . The second conveyor  11  is constituted by the single belt conveyor unit  12 . Like the belt conveyor unit  6 , the belt conveyor unit  12  includes, in addition to the above-described belt pulleys  55 ,  57 , a conveyor belt  59 , a platen  63  and a second charge roller (not shown). The belt conveyor unit  12  is held by the main frame  4  via the second supporter  119 . When the first conveyor  7  takes the first angular posture, the belt conveyor unit  6  and the belt conveyor unit  12  are interconnected via a conveying guide  67  that extends along a horizontal plane, so that the conveying guide  67  serves to guide the sheet (conveyed by the belt conveyor unit  6 ) toward the belt conveyor unit  12 . The conveying guide  67  is fixed to the main frame  4 . 
     The belt pulleys  55 ,  57  are arranged in the right-left direction, and extend in the front-rear direction. The belt pulleys  55 ,  57  are both positioned in the same height position as the belt pulley  33 . That is, the height positions of the respective belt pulleys  55 ,  57  are same to each other, and are same to the height position of the belt pulley  33 . The belt pulley  55 , which is a left-side one of the belt pulleys  55 ,  57 , is a drive pulley that is to be rotated by a motor (not shown) when the motor receives, from the controller  100 , a command requesting of rotation of the belt pulley  55 . The belt pulley  57 , which is a right-side one of the belt pulleys  55 ,  57 , is a driven pulley. The shaft of the belt pulley  55  is connected to ground. The belt pulley  55  is rotated by a driving force of the motor, in clockwise direction as seen in  FIG. 1 . The shafts of the respective belt pulleys  55 ,  57  are introduced in through-holes of the walls  122 ,  123  of the second supporter  119  and also in through-holes of the main frame  4 . 
     The conveyor belt  59  is an endless belt that is stretched around the two belt pulleys  55 ,  57 . When the belt pulley  55  is rotated by the driving force of the motor in the clockwise direction as seen in  FIG. 1 , an upper-side surface of the conveyor belt  59 , which is opposed to the set of second recording heads  13 , is caused to run in the rightward direction as seen in  FIG. 1 . This upper-side surface is provided by an upper portion of the outer circumferential surface of the conveyor belt  59 , and constitutes a supporting surface  60  defines the second conveyance path along which the sheet is to be conveyed by the second conveyor  11 . That is, the supporting surface  60  supports the sheet held thereon, and the conveyor belt  59  is circulated for thereby conveying the sheet in the rightward direction. Since the supporting surface  60  of the conveyor belt  59  is parallel to a horizontal plane, the sheet conveyed by the conveyor belt  59  is moved along the horizontal plane. 
     The platen  63  is fixed to the second supporter  119 , and is disposed to be in contact with an upper portion of an inner circumferential surface of the conveyor belt  59 , so as to support the conveyor belt  59 . Owing to the platen  63 , the supporting surface  60  of the conveyor belt  59  keeps a flat shape. 
     The second charge roller (not shown) has substantially the same construction as the first charge roller  41 . The second charge roller is disposed in proximity with the belt pulley  55 , and is held in contact with the outer circumferential surface of the conveyor belt  59 . The second charge roller is rotatably supported by the second supporter  119 . The second charge roller includes a shaft (about which the second charge roller is to be rotated) that is made of a metallic material, and an outer peripheral portion that is made of an elastic material having insulating properties or semi-conducting properties. The shaft of the second charge roller is connected to a positive pole of a second direct-current source (not shown) that is to be activated when the second direct-current source receives, from the controller  100 , a command requesting of activation of the second direct-current source. A negative pole of the second direct-current source is connected to ground. 
     When a predetermined level of electric voltage is applied to the shaft of the second direct-current source, an electrical discharge is generated between the second charge roller and the conveyor belt  59 . By the electrical discharge from the second charge roller, the conveyor belt  59  is charged with a positive charge. When the sheet is conveyed from the conveying guide  67  to the conveyor belt  59 , the sheet is attracted onto the conveyor belt  59 . Thus, by circulating the conveyor belt  59  to which the sheet is attracted, the sheet is conveyed along the second conveyance path that is defined by the supporting surface  60  of the conveyor belt  59 , in the rightward direction as seen in  FIG. 1 . In the present embodiment, the belt pulley  55 , second charge roller and second direct-current source cooperate to constitute another attraction generating device that is configured to cause the sheet to be attracted to the conveyor belt  59 . 
     &lt;Second Recording Heads  13 &gt; 
     The second recording heads  13  are to be activated, when the second recording heads  13  receive, from the controller  100 , a command requesting of activation of the heads  13 , for thereby ejecting inks toward the sheet that is being conveyed by the second conveyor  11 . The second recording heads  13  consist of three color recording heads that are configured to eject magenta, cyan and yellow inks toward the sheet. Each of the second recording heads  13  is a generally rectangular-parallelepiped-shaped head, as shown in  FIG. 3 , and is configured to eject ink having supplied from a corresponding one of three ink tanks (not shown) storing the respective magenta, cyan and yellow inks, toward the sheet through a plurality of nozzles that open in a nozzle opening surface  69  of the head. As shown in  FIG. 1 , the nozzle opening surface  60  constitutes a bottom surface of each of the second recording heads  13 . 
     As shown in  FIG. 1 , the second recording heads  13  are supported by the second supporter  119  such that the nozzle opening surface  69  of each of the heads  13  and the supporting surface  60  of the conveyor belt  50  are opposed to each other with a predetermined distance therebetween. Specifically, the set of second recording heads  13  has a front surface and a rear surface, and the front and rear surfaces have second projecting portions (not shown) which extend outwardly. Similarly as the above-described first projecting portions  51 ,  53 , the second projecting portions are fixed to supporting projections of the second supporter  119 , respectively, whereby the set of second recording heads  13  is supported by the second supporter  119 . 
     &lt;Third Conveyor  15 &gt; 
     As shown in  FIG. 2 , the third conveyor  15  is configured to convey the sheet (conveyed by the first conveyor  7  when the first conveyor  7  takes the second angular posture) further in the rightward direction, along a third conveyance path that is other than the second conveyance path defined by the second conveyor  11 . The third conveyor  15  is configured to convey the sheet, by causing the sheet to bypass the second conveyor  11 . That is, the third conveyance path defined by the third conveyor  15  is a bypass that bypasses the second conveyance path. The sheet, which is conveyed by the first conveyor  7  and the third conveyor  15 , is moved along bold arrows (black arrows) in  FIG. 2 . The third conveyor  15  includes conveying guides  71 ,  73 , a spur roller (rowel)  75  and pairs of conveying rollers  77 ,  78 ,  79 . 
     The conveying guide  71  is fixed to the main frame  4 , and extends in a right downward direction. The conveying guide  71  is aligned with the supporting surface  38  of the conveyor belt  37  of the first conveyor  7  when the first conveyor  7  takes the second angular posture. The conveying guide  71  serves to guide the sheet (conveyed by the first conveyor  7  when the first conveyor  7  takes the second angular posture) further in the right downward direction. 
     The conveying guide  73  is fixed to the main frame  4 , and includes a rightwardly extending portion and an upwardly extending portion extending from the rightwardly extending portion. The rightwardly extending portion extends rightwardly from a right lower end portion of the conveying guide  71 . The upward extending portion extends curvedly in an upward direction. The conveying guide  73  serves to guide the sheet that has been guided by the conveying guide  71 . The third conveyance path, along which the sheet is to be conveyed by the third conveyor  15 , is defined by cooperation of the guides  71 ,  73 . 
     The spur roller  75  is disposed on halfway of the conveying guide  71 , and has a sharp-toothed surface as its outer circumferential surface. The spur roller  75  is rotatably held by the main frame  4 . Even if the sheet (that is conveyed by the first conveyor  7  when the first conveyor  7  takes the second angular posture) is brought into contact at its leading end portion with the spur roller  75 , the conveyance of the sheet is not impeded by resistance applied to the sheet, because the resistance is reduced by rotation of the spur roller  75 . Further, although the spur roller  75  is brought into contact at its outer circumferential surface with a recorded surface of the sheet, there is substantially no risk that an image recoded on the recorded surface of the sheet is damaged by the spur roller  75 , because the outer circumferential surface of the spur roller  75  is the sharp-toothed surface. It is notated that the spur roller  75  may be either a driven roller or a drive roller that is to be rotated by a motor. It is further noted that the spur roller  75  is not essential and may not be provided. 
     The pairs of conveying rollers  77 ,  78 ,  79  are rotatably held by the main frame  4 , and are disposed on halfway of the conveying guide  73 . One of each of the pairs of conveying rollers  77 ,  78 ,  79  is a drive roller that is to be rotated by a motor (not shown) when the motor receives, from the controller  100 , a command requesting of rotation of the drive roller. The other of each of the pairs of conveying rollers  77 ,  78 ,  79  is a driven roller that is to be rotated by rotation of the drive roller. The pairs of conveying rollers  77 ,  78 ,  79  serve to convey the sheet (that is being guided by the conveying guide  73 ) toward the sheet discharger  17 . 
     &lt;Sheet Discharger  17 &gt; 
     The sheet discharger  17  is configured to discharge the sheet (conveyed by the second conveyor  11  or the third conveyor  15 ) toward the sheet exit tray  3 . The sheet discharger  17  includes a conveying guide  81  and pairs of conveying rollers  85 ,  87 . 
     The conveying guide  81  is fixed to the main frame  4 , and extends upwardly from a right end portion of the second conveyor  11  and an upper end portion of the third conveyor  15 . The conveying guide  81  serves to guide the sheet (conveyed by the second conveyor  11  or third conveyor  15 ) in an upward direction. 
     The pairs of conveying rollers  85 ,  87  are rotatably held by the main frame  4 , and are disposed on halfway of the conveying guide  81 . One of each of the pairs of conveying rollers  85 ,  87  is a drive roller that is to be rotated by a motor (not shown) when the motor receives, from the controller  100 , a command requesting of rotation of the drive roller. The other of each of the pairs of conveying rollers  85 ,  87  is a driven roller that is to be rotated by rotation of the drive roller. The pair of conveying roller  85 , which are disposed on a lower side of the pair of conveying rollers  87 , serve to convey the sheet (that is being guided by the conveying guide  81 ) upwardly toward the pair of conveying rollers  87 . A sheet sensor  88  is disposed in vicinity of the pair of conveying rollers  85 . The sheet sensor  88  is configured to detect the sheet conveyed from the second conveyor  11  or the third conveyor  15 , and to supply, to the controller  100 , a signal indicative of detection of the sheet. The pair of conveying rollers  87 , which are disposed on an upper side of the pair of conveying rollers  85 , are rotated in forward directions, when the sheet is to be discharged to the sheet exit tray  3 , for thereby discharging the sheet (that has been guided by the conveying guide  81 ) to the sheet exit tray  3 . On the other hand, when the sheet is to be guided to the return conveyor  19 , the pair of conveying rollers  87  are first rotated in the above-described forward directions, and then rotated in reverse directions opposite to the forward directions with a trailing end portion of the sheet being nipped by the pair of conveying rollers  85  (disposed in vicinity of the sheet sensor  88 ), for thereby conveying the sheet to the return conveyor  19 . 
     &lt;Return Conveyor  19 &gt; 
     The return conveyor  19  is configured to convey the sheet from the sheet discharger  17  back to the first conveyor  7 , along bold arrows (hatched arrows) in  FIGS. 1 and 2 . The return conveyor  19  includes conveying guides  73 ,  89  and pairs of conveying rollers  78 ,  79 ,  91 . It is noted that the conveying guide  73  and the pairs of conveying rollers  78 ,  79  are common to the return conveyor  19  and the third conveyor  15 . 
     The conveying guide  73  serves to guide the sheet (conveyed by the above-described opposite rotations of the pair of conveying rollers  87 ) to be moved in a left downward direction. 
     The conveying guide  89  is fixed to the main frame  4 , and includes a leftwardly extending portion and an upwardly extending portion extending from the leftwardly extending portion. The leftwardly extending portion extends leftwardly from a junction of the conveying guides  71 ,  73 . The upwardly extending portion extends curvedly in an upward direction, and reaches the conveying guide  29 . Specifically, the upwardly extending portion of the conveying guide  89  is connected to a portion of the conveying guide  29  which is located below the pair of conveying rollers  31 . The conveying guide  89  serves to guide the sheet (that has been guided by the conveying guide  73  by the rotations of the conveying rollers  87  in the reverse directions) toward the conveying guide  29 . 
     The pair of conveying rollers  78 ,  79  serve to convey the sheet (that is conveyed by the rotations of the conveying rollers  87  in the reverse directions) toward the conveying guide  88 . 
     The pair of conveying rollers  91  are fixed to the main frame  4 , and are disposed on halfway of the conveying guide  89 . One of the conveying rollers  91  is a drive roller that is to be rotated by a motor (not shown) when the motor receives, from the controller  100 , a command requesting rotation of the drive roller. The other of the conveying rollers  91  is a driven roller that is to be rotated together with rotation of the drive roller. The pair of conveying rollers  91  serve to convey the sheet that is being guided by the conveying guide  29 , toward the conveying guide  29 . 
     &lt;Posture Changer  21 &gt; 
     The posture changer  21  is configured to change the angular posture of each of the first conveyor  7  and the first recording head  9 , by pivoting the first supporter  93 . As shown in  FIG. 4 , the posture changer  21  includes the above-described forcing portion  101  and a drive mechanism  95  configured to pivot the first supporter  93 . 
     The forcing portion  101  is constituted by a spring that is interposed between the contact portion  99  of the first supporter  93  and the support plate  109  that is formed integrally with the main frame  4 . A lower end portion of the spring is fixed to the contact portion  99  while an upper end portion of the spring is fixed to the support plate  109 . The spring has a length which is larger than a distance between the support plate  109  and the contact portion  99 . More specifically, the spring has a natural length which is larger than the distance between the support plate  109  and the contact portion  99  not only when the first conveyor  7  takes the first angular posture but also when the first conveyor  7  takes the second angular posture. Thus, the spring is being compressed while being interposed between the support plate  109  and the contact portion  99 . The forcing portion  101  is configured to force the contact portion  99  in a downward direction. With the contact portion  99  being forced downwardly by the forcing portion  101 , the first supporter  93  can be reliably pivoted by rotation of the eccentric cam  111 . 
     As shown in  FIG. 4 , the drive mechanism  95  includes, in addition to the eccentric cam  111 , a motor  114  and three gears  115 ,  116 ,  117 . 
     The eccentric cam  111  is rotatably held by the main frame  4 , and is rotatable about a center of rotation which is offset from a gravitational center or a geometric center of the eccentric cam  111 . The center of rotation of the eccentric cam  111  is located on a right side of the axis of the belt pulley  33 . The eccentric cam  111  has an outer circumferential surface serving as a cam surface, and an upper portion of the outer circumferential surface of the cam  111  is held in contact with a lower surface  102  of the contact portion  99 . 
     The gear  115  serves to transmit rotation of the motor  114 , which is rotated when the motor  114  receives, from the controller  100 , a command requesting of rotation of the motor  114 . The gear  116  meshes with the gear  115 . The gear  117  meshes with the gear  116 , and is rotatable together with the eccentric cam  111 . The gear  117  and the eccentric cam  111  are both fixed to a rotary shaft that is rotatably held by the main frame  4 . That is, the gear  117  and the eccentric cam  111  are rotatable about the same axis. With the motor  114  being rotated, the rotation of the motor  114  is transmitted via the three gears  115 ,  116 ,  117  to the eccentric cam  111  whereby the cam  111  is rotated. The three gears  115 ,  116 ,  117  are rotatably held by the main frame  4 . The motor  114  is fixed to the main frame  4 . 
     With the eccentric cam  111  being rotated, a height of the upper portion of the outer circumferential surface of the cam  111  is changed. As a result of change of the height of the upper portion of the outer circumferential surface of the cam  111 , a height of the contact portion  99  is changed. As a result of change of the height of the contact portion  99 , an entirety of the first supporter  93  is pivoted about the axis of the belt pulley  33 . 
     As described above, with the first supporter  93  being pivoted by the posture changer  21 , the angular postures of the first conveyor  7  and the first recording head  9  are changed. When the first conveyor  7  takes the first angular posture, the supporting surface  38  of the conveyor belt  37  is made substantially flush with the supporting surface  60  of the conveyor belt  59 . That is, when the first conveyor  7  takes the first angular posture, the first conveyance path is directed to the second conveyance path defined by the second conveyor  11 , such that the first conveyance path is aligned with the second conveyance path without a step between the first and second conveyance paths. On the other hand, when the first conveyor  7  takes the second angular position, the supporting surface  38  of the conveyor belt  37  is made substantially flush with the conveying guide  72 . That is, when the first conveyor  7  takes the second angular position, the first conveyance path is directed to the third conveyance path defined by the third conveyor  15 , such that the first conveyance path is aligned with the third conveyance path without a step between the first and third conveyance paths. 
     &lt;Recording Operation&gt; 
     There will be described a both-side color recording and a both-side monochrome recording which are to be performed in the inkjet printer  1 . It is noted that an one-side color recording and an one-side monochrome recording will not be described in detail, since the one-side recording is different from the both-side recording, merely in that a sheet is discharged to the sheet exit tray  3  when the recording has been performed onto one-side surface of the sheet. 
     When the controller  100  receives, from PC (personal computer), recording data representing color images that are to be recorded onto both-side faces of a sheet, the controller  100  controls the drive mechanism  95  such that the first conveyor  7  takes the first angular posture as shown in  FIG. 1 . 
     The controller  100  controls the sheet supplying roller  27  and the pair of conveying rollers  31  such that the sheet is conveyed from the sheet supplying cassette  23  to the first conveyor  7  via the conveying guide  29 . 
     The controller  100  controls the first conveyor  7  such that the sheet is conveyed in a rightward direction while being attracted to the conveyor belt  37 . More precisely described, the controller  100  controls the first conveyor  7  such that the attraction generating device causes, even before the sheet reaches the conveyor belt  37 , the outer circumferential surface of the conveyor belt  37  to have an attraction force by which the sheet is attracted onto the outer circumferential surface of the conveyor belt  37 . In this instance, since the first conveyor  7  takes the first angular posture, the supporting surface  38  of the conveyor belt  37  is parallel to a horizontal plane, so that the sheet conveyed by the conveyor belt  37  is moved along the horizontal plane in the rightward direction. When a leading end portion of the sheet reaches the sheet sensor  44 , the sheet sensor  44  supplies, to the controller  100 , a signal indicative of detection of the sheet by the sheet sensor  44 . The controller  100  controls the first recording head  9  such that ink is ejected from the first recording head  9  when the sheet passes a region that is opposed to the first recording head  9 , namely, when a given length of time has passed from the detection of the leading end portion of the sheet by the sheet sensor  44 . 
     Then, the controller  100  controls the second conveyor  11 , such that the sheet (conveyed to the second conveyor  11  via the conveying guide  67 ) is conveyed by the second conveyor  11  in the rightward direction while being attracted to the conveyor belt  59 . The controller  100  controls the second recording heads  13  such that inks are ejected from the second recording heads  13  when the sheet passes a region that is opposed to the second recording heads  13 , namely, when a given length of time has passed from the detection of the leading end portion of the sheet by the sheet sensor  44 . The sheet is opposed to the nozzle opening surfaces  45 ,  69  of the first and second recording heads  9 ,  13  while being conveyed by the first and second conveyors  7 ,  11 , and color image is recorded in a desired portion of a top surface of the sheet. 
     Then, the controller  100  controls the pairs of conveying rollers  85 ,  87  such that the sheet (conveyed by the conveyor belt  59 ) is conveyed toward the sheet exit tray  3  via the conveying guide  81 . When a trailing end portion of the sheet reaches the sheet sensor  88 , the sheet sensor  88  supplies, to the controller  100 , a signal indicative of detection of the trailing end portion of the sheet by the sheet sensor  88 . When having received the detection signal supplied from the sheet sensor  88 , the controller  100  controls the pair of conveying rollers  87  such that directions of the rotations of the conveying rollers  87  are switched from the forward directions to the reverse directions. 
     Then, the controller  100  controls the pairs of conveying rollers  79 ,  78 ,  91  such that the sheet (conveyed by the reverse rotations of the pair of conveying rollers  87 ) is conveyed back to the pair of conveying rollers  31  via the conveying guides  73 ,  89 . When reaching the pair of conveying rollers  31 , the sheet has been inverted whereby the top and bottom faces of the sheet are caused to face downwardly and upwardly, respectively. Then, the controller  100  controls the pair of conveying rollers  31  such that the inverted sheet is conveyed to the first conveyor  7 . 
     Then, the controller  100  controls the first conveyor  7 , first recording head  9 , second conveyor  11  and second recording heads  13  in a same manner as when the color image has been recorded on the top face of the sheet, such that a desired color image is recorded on the bottom face of the sheet. Then, the controller  100  controls the pair of conveying rollers  87  such that the sheet having the images recoded on its top and bottom faces is discharged to the sheet exit tray  3 . Thus, the both-side color recording is completed. 
     In a case where monochrome images are to recoded onto both-side faces of a sheet, when the controller  100  receives, from PC (personal computer), recording data representing the monochrome images that are to be recorded onto the both-side faces of the sheet, the controller  100  controls the drive mechanism  95  such that the first conveyor  7  takes the second angular posture as shown in  FIG. 2 . 
     The controller  100  controls the sheet supplying roller  27  and the pair of conveying rollers  31  such that the sheet is conveyed from the sheet supplying cassette  23  to the first conveyor  7  via the conveying guide  29 . 
     The controller  100  controls the first conveyor  7  such that the sheet is conveyed in a rightward direction while being attracted to the conveyor belt  37 . In this instance, since the first conveyor  7  takes the second angular posture, the supporting surface  38  of the conveyor belt  37  is inclined with respect to a horizontal plane, so that the sheet conveyed by the conveyor belt  37  is moved in a right downward direction. The controller  100  controls the first recording head  9  such that ink is ejected from the first recording head  9  when the sheet passes a region that is opposed to the first recording head  9 , namely, when a given length of time has passed from the detection of the leading end portion of the sheet by the sheet sensor  44 . 
     Then, the controller  100  controls the pairs of conveying rollers  78 ,  79 ,  85 ,  87  such that the sheet (conveyed by the first conveyor  7 ) is conveyed by the third conveyor  15  toward the sheet exit tray  3 . The sheet is opposed to the nozzle opening surface  45  of the first recording head  9 , while being conveyed by the first conveyor  7 , and monochrome image is recorded in a desired portion of a top surface of the sheet. When having received the detection signal supplied from the sheet sensor  88 , the controller  100  controls the pair of conveying rollers  87  such that directions of the rotations of the conveying rollers  87  are switched from the forward directions to the reverse directions. 
     Then, the controller  100  controls the pairs of conveying rollers  79 ,  78 ,  91  such that the sheet is conveyed to the pair of conveying rollers  31  via the conveying guides  73 ,  89 . When reaching the pair of conveying rollers  31 , the sheet has been inverted whereby the top and bottom faces of the sheet are caused to face downwardly and upwardly, respectively. Then, the controller  100  controls the pair of conveying rollers  31  such that the inverted sheet is conveyed to the first conveyor  7 . 
     Then, the controller  100  controls the first conveyor  7 , first recording head  9  and third conveyor  15  in a same manner as when the monochrome image has been recorded on the top face of the sheet, such that a desired monochrome image is recorded on the bottom face of the sheet. Then, the controller  100  controls the pairs of conveying rollers  78 ,  79 ,  85 ,  87  such that the sheet having the images recoded on its top and bottom faces is discharged to the sheet exit tray  3 . Thus, the both-side monochrome recording is completed. 
     During both-side monochrome recording, the sheet is conveyed by the third conveyor  15  in place of the second conveyor  11 . That is, during the both-side monochrome recording, the sheet is conveyed along the third conveyance path which is defined by the third conveyor  15  and which is other than the second conveyance path defined by the second conveyor  11 . Therefore, it is possible to restrain foreign substances such as paper dust from adhering onto the nozzle opening surfaces  69  of the second recording heads  13  which are opposed to the conveyor belt  59  of the second conveyor  11 . Since the adhesion of the foreign substances to the nozzle opening surfaces  69  of the second recording heads  13  can be restrained, it is possible to reduce the number of times at which maintenance operations (such as flushing and purging operations for ejecting ink through nozzles for cleaning purpose) are required to be carried out. Consequently, it is possible to save an amount of ink that is be consumed in the maintenance operations. It is noted that, when the first conveyor  7  takes the second angular posture, the nozzle opening surfaces  69  of the respective second recording heads  13  may be closed by, for example, an annular-shaped cap (not shown) which is to be disposed to surround periphery of the set of second recording heads  13  and which is to be brought into contact with the supporting surface  60  of the conveyor belt  59 , so that the nozzle opening surfaces  69  of the second recording heads  13  are covered by cooperation of the annular-shaped cap and the supporting surface  60 . Owing to this arrangement with the annular-shaped cap, the required number of times of the maintenance operations can be further reduced. 
     &lt;Effects of the First Embodiment&gt; 
     In the above embodiment, the angular posture of the first conveyor  7 , which applies a conveying force to the sheet while attracting the sheet thereto, is changed whereby the angular posture of the first conveyor  7  is changed between the first angular posture and the second angular posture. When the first conveyor  7  takes the first angular posture, as shown in  FIG. 1 , the supporting surfaces  38 ,  60  of the conveyor belts  37 ,  59  are substantially flush with each other, so that a conveyance path interconnecting the first and second conveyors  7 ,  11  (i.e., interconnecting the first and second conveyance paths) is not substantially bent or curved. Therefore, the sheet can be conveyed from the first conveyor  7  to the second conveyor  11 , without the sheet receiving a large convey resistance, which is a force applied to the sheet and acting in a direction opposite to the conveyance direction. Since a large convey resistance is not applied to the sheet, a velocity of the conveyed sheet is not momentarily reduced by a large amount. Therefore, even if the recording is being carried out by the first recording head  9  when the sheet is conveyed from the first conveyor  7  to the second conveyor  11 , it is possible to avoid deterioration of quality of the recoded image, which could be caused if the velocity of the conveyed sheet were momentarily reduced by a large amount. 
     On the other hand, when the first conveyor  7  takes the second angular position, the supporting surface  38  of the conveyor belt  37  is inclined so as to extend in a right downward direction, whereby the supporting surface  38  is made substantially flush with the conveying guide  72  so that a conveyance path interconnecting the first conveyor  7  and third conveyor  15  (i.e., interconnecting the first and third conveyance paths) is not substantially bent or curved. Further, since the conveyor belt  37  attracts the sheet thereto while conveying the sheet, the sheet is attracted onto the supporting surface  38  of the conveyor belt  37 , so that the sheet can be reliably conveyed by the conveyor belt  37 , although the supporting surface  38  of the conveyor belt  37  constitutes a downslope surface, i.e., a slope surface that is inclined such that the slope surface has a height that is reduced in the first conveyance direction. Further, since the sheet is conveyed from the first conveyor  7  to the third conveyor  11  without receiving a large convey resistance, the velocity of the conveyed sheet is not momentarily reduced by a large amount. Therefore, even if the recording is being carried out by the first recording head  9  when the sheet is conveyed from the first conveyor  7  to the third conveyor  15 , it is possible to avoid deterioration of quality of the recoded image, which could be caused if the velocity of the conveyed sheet were momentarily reduced by a large amount. 
     According to the features of the first embodiment as described above, an increase of the size of the apparatus can be prevented, an amount of ink consumption can be reduced, and a reduction of the recorded image quality can be prevented. 
     If the angular posture of the first conveyor  7  were not changeable, a degree of curvature or bending of the conveyance path interconnecting the first and third conveyors  7 ,  15  cannot be reduced without increasing a distance between the first and third conveyors  7 ,  15 , namely, without increasing a size of the apparatus as a whole. That is, the degree of curvature or bending of the conveyance path interconnecting the first and third conveyors  7 ,  15  would be increased where a reduction of the distance between the first and third conveyors  7 ,  15  is intended, namely, where a reduction of the size of the apparatus as a whole is intended. Further, in this arrangement in which the angular posture of the first conveyor  7  is not changeable, it might be possible to provide a pivotable flapper in a fork in which the first conveyance path is diverged into the second and third conveyance paths such that the sheet is conveyed from the first conveyor  7  to a selected one of the second conveyor  11  and third conveyor  15  which is selected depending on a posture of the pivotable flapper that does not apply a conveying force to the sheet. However, in this arrangement with the pivotable flapper, where the sheet is to be conveyed from the first conveyor  7  to the third conveyor  15 , the direction of the conveyance is abruptly changed upon collision of the leading end of the sheet with the flapper. By the collision of the leading end of the sheet with the flapper, a large convey resistance is momentarily applied to the sheet, whereby the velocity of the conveyed sheet is momentarily reduced by a large amount, so that the image recorded by the first recording head  9  could be disordered. 
     In the above-described first embodiment, the first supporter  93  is pivotable about the axis of the belt pulley  33 , so that a position of the belt pulley  33  is not changed irrespective of whether the first conveyor  7  takes the first angular posture or second angular posture. Therefore, irrespective of the angular posture of the first conveyor  7 , the sheet (conveyed by the sheet supplier  5 ) can be stably conveyed by the conveyor belt  37  after having reached the conveyor belt  37 . 
     In the above-described first embodiment, the first supporter  93  is pivotable by rotation of the eccentric cam  111 . Described specifically, the height of the contact portion  99  of the first supporter  93  is dependent on the height of the upper surface of the eccentric cam  111 , and the first supporter  93  supporting the first conveyor  7  is pivotable. That is, the first supporter  93  is positioned in a position that is dependent on the height of the upper surface of the eccentric cam  111 , the positioning of the first supporter  93  can be made accurately. Further, the forcing portion  101  is provided to force the contact portion  66  in a direction toward the upper surface of the eccentric cam  111 , so that the pivot motion of the first supporter  93  can be reliably linked to the rotation of the eccentric cam  111 . 
     &lt;Modifications of First Embodiment&gt; 
     In the above-described first embodiment, the first conveyor  7  includes a single conveyor unit in the form of the belt conveyor unit  6  that is configured to cause a sheet to be attracted onto the supporting surface  38  of the conveyor belt  37  and to convey the sheet. However, this arrangement is not essential. For example, the first conveyor  7  may include, in place of the belt conveyor unit  6 , pairs of conveying rollers and a platen for supporting a sheet, wherein the pairs of conveying rollers are disposed on upstream and downstream sides of the first recording head  9 , and wherein the platen is disposed to be opposed to the nozzle opening surface  45  of the first recording head  9 . In this modification, the first conveyor  8  may include an attraction generating device that is provided for the platen, for causing a sheet to be attracted onto a supporting surface of the platen. As the attraction generating device, it is possible to employ a pair of comb-teeth-like electrodes as disclosed, for example, in JP-H07-330185A. The comb-teeth-like electrodes are spaced apart from each other by a given distance, for avoiding a short connection between the electrodes. Each of the comb-teeth-like electrodes has a plurality of elongated portions which are elongated in the right-left direction and which are arranged in the front-rear direction. With application of an electric voltage between the comb-teeth-like electrodes, an attraction force based on a static electricity can be generated on the supporting surface of the platen. 
     In the above-described first embodiment, the second conveyor  11  includes a single conveyor unit in the form of the belt conveyor unit  12  that is configured to cause a sheet to be attracted onto the supporting surface  60  of the conveyor belt  59  and to convey the sheet. However, this arrangement is not essential. For example, the second conveyor  11  may include, in place of the belt conveyor unit  12 , pairs of conveying rollers and a platen for supporting a sheet, wherein the pairs of conveying rollers are disposed on upstream and downstream sides of the set of second recording heads  13 , and wherein the platen is disposed to be opposed to the nozzle opening surfaces  69  of the respective second recording heads  13 . In this modification, the second conveyor  11  may not include an attraction generating device configured to cause a sheet to be attracted onto a supporting surface of the platen. 
     In the above-described first embodiment, the belt conveyor unit  6  includes the attraction generating device which is constituted by the belt pulley  33 , first charge roller  41  and first direct-current source  43  and which is configured to provide the conveyor belt  37  with the attraction force that is generated based on a static electricity. Further, the belt conveyor unit  12  includes the attraction generating device which is constituted by the belt pulley  55 , second charge roller and second direct-current source and which is configured to provide the conveyor belt  59  with the attraction force that is generated based on a static electricity. However, these arrangements are not essential. For example, a pair of comb-teeth-like electrodes may be disposed on a surface of each of the platens  40 ,  63  which is in contact with a corresponding one of the conveyor belts  37 ,  59 , wherein the comb-teeth-like electrodes are spaced apart from each other by a given distance, for avoiding a short connection between the electrodes. Each of the comb-teeth-like electrodes has a plurality of elongated portions which are elongated in the right-left direction and which are arranged in the front-rear direction. With application of an electric voltage between the comb-teeth-like electrodes, an attraction force based on a static electricity can be generated in the conveyor belts  37 ,  59 . In this modification, the belt conveyor units  6 ,  12  do not have to include the first charge roller  41  and second charge roller, respectively. 
     In the above-described first embodiment, each of the conveyor belts  37 ,  59  is given the attraction force based on the static electricity, whereby a sheet is caused to be attracted onto a corresponding one of the supporting surfaces  38 ,  60 . However, this arrangement is not essential. For example, each of the conveyor belts  37 ,  59  may be constituted by a belt having self-bonding properties, so that a sheet can be attracted to the belt owing to the self-bonding properties. Further, as another example, a sucking device may be provided for sucking air through holes that are formed through the conveyor belts  37 ,  59 , for thereby enabling a sheet to be attracted to the conveyor belts  37 ,  59 , owing to a sucking force that is generated by the sucking device. 
     In the above-described first embodiment, the conveyor belts  37 ,  59  are stretched around the belt pulleys  33 ,  35 ,  55 ,  57 , and the upstream-side belt pulleys  33 ,  55  serve as drive rollers. However, the downstream-side belt pulleys  35 ,  57 , in place of the upstream-side belt pulleys  33 ,  55 , may serve as drive rollers. 
     In the above-described first embodiment, when the first conveyor  7  takes the first angular posture, the supporting surfaces  38 ,  60  of the respective conveyor belts  37 ,  59  are substantially flush with each other. However, in this instance, the second conveyor  11  may be located either on an upper side or a lower side of the first conveyor  7 . In this modification, too, the first angular posture of the first conveyor  7  is an angular posture of the first conveyor  7  by which the first conveyance path (defined by the supporting surface  38  of the conveyor belt  37 ) is directed to the second conveyance path (defined by the supporting surface  60  of the conveyor belt  59 ). Further, in the above-described first embodiment, the third conveyor  15  is located on a lower side of the first conveyor  7 . However, the third conveyor  15  may be located on an upper side of the first conveyor  7  or located in the same height position as the first conveyor  7 . In this modification, too, the second angular posture of the first conveyor  7  is an angular posture of the first conveyor  7  by which the first conveyance path (defined by the supporting surface  38  of the conveyor belt  37 ) is directed to the third conveyance path (defined by the conveying guides  71 ,  73 ). It is noted that, where the third conveyor  15  is located in the same height position as the first conveyor  7 , the supporting surface  38  of the conveyor belt  37  is substantially flush with the conveying guides  71 ,  73 . 
     In the above-described first embodiment, the first recording head  9  is a black recording head that is configured to eject black ink in a monochrome recording. However, for example, the first recording head  9  may be a color recording head that is configured to eject color inks in a color recording. Further, as another example, the first recording head  9  may be configured to eject liquid other than ink. Such a liquid may be a liquid that is to be ejected toward a sheet in a pre-recording operation that is to be carried out, prior to ejection of the ink, for the purpose of facilitating fixation of the ink onto the sheet or increasing color-developing properties of the ink. 
     In the above-described first embodiment, the set of second recording heads  13  consist of three color recording heads that are configured to eject magenta, cyan and yellow inks. However, for example, the set of second recording heads  13  may consist of four or more recording heads including a recording head that is configured to eject the other color ink such as light magenta and light cyan inks. Further, as another example, the second recording heads  13  may be a black recording head that is configured to eject black ink in a monochrome recording. Still further, the second recording heads  13  may be configured to eject liquid other than ink. Such a liquid may be a liquid that is to be ejected toward a sheet in a post-recording operation that is to be carried out, after ejection of the ink, for the purpose of facilitating fixation of the ink onto the sheet or increasing color-developing properties of the ink. 
     In the above-described first embodiment, the first supporter  93  is constructed to support the first conveyor  7  and the first recording head  9 . However, the first supporter  93  may be constructed to support only the first conveyor  7 , as long as the first recording head  9  is supported by another member. In this modification, the angular posture of the first recording head  9  is changed such that the nozzle opening surface  45  of the first recording head  9  and the supporting surface  38  of the conveyor bet  37  are opposed to each other and are spaced apart from each other by a distance that is constant irrespective of change of the angular posture of the first conveyor  7 . 
     In the above-described first embodiment, the first supporter  93  is constructed to support the belt conveyor unit  6  except the first charge roller  41 . However, the first supporter  93  may be construed to support the entirety of the belt conveyor unit  6  including the first charge roller  41 . Further, the first supporter  93  does not have to support all or many of the components of the belt conveyor unit  6 , as long as the first supporter  93  supports at least the belt pulleys  33 ,  35 . 
     In the above-described first embodiment, the posture changer  21  is constructed to cause the first conveyor  7  and the first recording head  9  to be pivoted by rotation of the eccentric cam  111 . However, the posture changer  21  may be otherwise constructed, as long as it is capable of causing the first conveyor  7  and the first recording head  9  to be pivoted together with each other. For example, the first supporter  93  may be provided with a rack that extends in a vertical direction while the drive mechanism  95  may be provided with a drive transmission mechanism and a pinion meshing with the rack, such that, for example, the first supporter  93  provided with the rack is pivotable, by rotation of the pinion, about the axis of the belt pulley  33 . 
     In the above-described first embodiment, the posture changer  21  includes the forcing portion  101 . However, the posture changer  21  may not include the forcing portion  101 . Further, in the first embodiment, the upper portion of the eccentric cam  111  is held in contact with the lower surface  102  of the contact portion  99 . However, the eccentric cam  111  and the contact portion  99  may be arranged such that a lower portion of the eccentric cam  111  is held in contact with an upper surface of the contact portion  99 . In this modification, too, the contact portion  99  is forced by a forcing portion in a direction toward the eccentric cam  111 . 
     In the above-described first embodiment, when the controller  100  receives recording data representing color images that are to be recorded onto both-side faces of a sheet, the controller  100  controls the drive mechanism  95  such that the first conveyor  7  takes the first angular posture. In this instance, the controller  100  may control the drive mechanism  95  such that the first conveyor  7  becomes to take the first angular posture before the sheet reaches the first conveyor  7 . Further, in the above-described first embodiment, when the controller  100  receives recording data representing monochrome images that are to be recorded onto both-side faces of a sheet, the controller  100  controls the drive mechanism  95  such that the first conveyor  7  takes the second angular posture. In this instance, the controller  100  may control the drive mechanism  95  such that the first conveyor  7  becomes to take the second angular posture before the sheet reaches the first conveyor  7 . Further, when the controller  100  receives recording data representing color image and monochrome image that are to be recorded onto one and the other of both-side faces of a sheet, respectively, the controller  100  may control the drive mechanism  95 , such that the first conveyor  7  takes the first angular position for recording of the color image onto the one of the both-side faces of the sheet, and such that the first conveyor  7  takes the second angular position for recording of the monochrome image onto the other of the both-side faces of the sheet. That is, the controller  100  may control the drive mechanism  95  such that the first conveyor  7  takes the first angular posture when color-image is to be recoded onto a sheet, and such that the first conveyor  7  takes the second angular posture when monochrome-image is to be recoded onto a sheet. 
     [Second Embodiment] 
     Referring next to  FIGS. 6 and 7 , there will be described an inkjet printer  201  that is constructed according to a second embodiment of the invention. In the following description regarding this second embodiment, the same reference numerals as used in the first embodiment will be used to identify the same or similar elements, and redundant description of these elements will not be provided. 
     In the inkjet printer  201 , a first conveyor  203  has a construction different from that of the first conveyor  7  of the inkjet printer  1  of the first embodiment. Due to the difference of the first conveyor  203  from the first conveyor  7  of the inkjet printer  1  of the first embodiment, the first supporter  93  and the conveying guides  67 ,  71  in this second embodiment are slightly different from those in the first embodiment with respect to construction. However, the same reference numerals will be used for these elements since they are substantially the same as those in the first embodiment. 
     &lt;First Supporter  93 &gt; 
     The first supporter  93  supports a belt conveyor unit  204  that will be described later in detail. As in the first embodiment, the first supporter  93  is pivotable by the posture changer  21 . The walls  103 ,  104  of the first supporter  93  have through-holes (not shown) in which shafts of respective belt pulleys  211 ,  212  are introduced. The shaft of the belt pulley  211  is introduced in the through-holes of the respective walls  103 ,  104  and also in a through-hole of the main frame  4 , so that the first supporter  93  is pivotable about the axis of the belt pulley  211 . 
     The walls  105 ,  106  are plate-like members extending and interconnecting the walls  103 ,  104 . In the first embodiment, the first recording head  9  is sandwiched by the walls  105 ,  106  from the left and right sides. However, in the second embodiment, the walls  105 ,  106  are not disposed in respective positions for sandwiching the first recording head  9 . 
     &lt;First Conveyor  203 &gt; 
     As shown in  FIG. 6 , the first conveyor  203  is configured to convey the sheet (conveyed by the sheet supplier  5 ) in the rightward direction. The first conveyor  203  includes two belt conveyor units  202 ,  204  which are arranged in the right-left direction. 
     The belt conveyor unit  202  includes belt pulleys  209 ,  210 , a conveyor belt  205 , a platen  215 , a pressing roller  213  and a third charge roller (not shown). Since the belt conveyor unit  202  has a construction substantially the same as those of the belt conveyor units  6 ,  12  in the first embodiment, redundant description of the belt conveyor unit  202  will not be provided. The belt pulleys  209 ,  210  are both positioned in the same height position as the belt pulley  55 . The belt conveyor unit  202  is held by the main frame  4 , and is configured to convey the sheet (which is held on a supporting surface  206  constituted by an upper portion of an outer circumferential surface of the conveyor belt  205 ) in the rightward direction. 
     The belt conveyor unit  204  includes belt pulleys  211 ,  212 , a conveyor belt  207 , a platen  217  and a fourth charge roller (not shown). Since the belt conveyor unit  204  has a construction substantially the same as those of the belt conveyor units  6 ,  12  in the first embodiment, redundant description of the belt conveyor unit  204  will not be provided. The belt conveyor unit  204  does not include a pressing roller that is to serve to press the sheet down onto the outer circumferential surface of the conveyor belt  207 . The belt conveyor unit  204  is supported by the first supporter  93 , like the belt conveyor unit  6  in the first embodiment. Describe specifically, the shaft of the belt pulley  211  is introduced in the through-holes of the walls  103 ,  104  of the first supporter  93  and also in the through-hole of the main frame  4 . By pivot motion of the first supporter  93 , the posture of the first conveyor  204  is changed between the first angular posture and the second angular posture. 
     In this second embodiment, the angular posture of only the belt conveyor unit  204 , which is a right-side one, i.e., downstream-side one of the two belt conveyor units  202 ,  204 , is changeable between the first angular posture and the second angular posture. That is, in the second embodiment, the angular posture of the belt conveyor unit  204 , which corresponds to a downstream-side portion of the first conveyor  203 , is changeable, while the angular posture of the entirety of the first conveyor  7  is changeable in the above-described first embodiment. 
     When the belt conveyor unit  204  takes the first angular posture as shown in  FIG. 6 , the belt pulley  212  is positioned in the same height position as the belt pulley  211 , and a supporting surface  208  (which is an upper-side surface provided by an upper portion of the outer circumferential surface of the conveyor belt  207 ) is parallel to a horizontal plane. Thus, the sheet conveyed by the conveyor belt  207  is moved along the horizontal plane in the rightward direction. That is, when the belt conveyor unit  204  takes the first angular posture, the sheet, which is conveyed by the first conveyor  203 , is moved in the rightward direction while being supported on the supporting surface  206  of the conveyor belt  205  and is then moved further in the rightward direction while being supported on the supporting surface  208  of the conveyor belt  207 . 
     On the other hand, when the belt conveyor unit  204  takes the second angular posture as shown in  FIG. 7 , the belt pulley  212  is positioned in a position lower than the belt pulley  211 , and the supporting surface  208  of the conveyor belt  207  is inclined with respect to a horizontal plane, in a right downward direction. Thus, the sheet conveyed by the conveyor belt  207  is moved in the right downward direction, while being supported on the supporting surface  208  of the conveyor belt  207 . That is, when the belt conveyor unit  204  takes the second angular posture, the sheet, which is conveyed by the first conveyor  203 , is moved in the rightward direction while being supported on the supporting surface  206  of the conveyor belt  205  and is then moved in the right downward direction while being supported on the supporting surface  208  of the conveyor belt  207 . In this second embodiment, the first conveyance path defined by the first conveyor  203  includes an upstream-side part defined by the supporting surface  206  of the conveyor belt  205  and a downstream-side part defined by the supporting surface  208  of the conveyor belt  207 . 
     &lt;First Recording Head  219 &gt; 
     The first recording head  219  is to be activated, when the first recording head  219  receives, from the controller  100 , a command requesting of activation of the head  219 , for thereby ejecting ink toward the sheet that is being conveyed by the conveyor belt  205  of the first conveyor  203 . 
     The first recording head  219  is fixed to the main frame  4  such that a nozzle opening surface (i.e., ejection surface)  220  of the first recording head  219  and the supporting surface  206  of the conveyor belt  205  are opposed to each other and spaced apart from each other by a predetermined distance. The first recording head  219 , which is fixed to the main frame  4 , has a fixed posture that is not changeable. 
     &lt;Posture Changer  21 &gt; 
     The posture changer  21  has the drive mechanism  95  that is configured to pivot the first supporter  93 . The posture changer  21  is configured to cause the first supporter  93  to be pivoted about the axis of the belt pulley  211 , thereby changing the posture of the belt conveyor unit  204  between the first angular posture and the second angular posture. 
     &lt;Effects of the Second Embodiment&gt; 
     In the above embodiment, the angular posture of the belt conveyor unit  204  as the downstream-side portion of the first conveyor  203 , which applies a conveying force to the sheet while attracting the sheet thereto, is changed whereby the angular posture of the belt conveyor unit  204  is changed between the first angular posture and the second angular posture. When the belt conveyor unit  204  takes the first angular posture, as shown in  FIG. 6 , the supporting surfaces  206 ,  208 ,  60  of the three conveyor belts  205 ,  207 ,  59  are substantially flush with each other, so that a conveyance path interconnecting the first and second conveyors  203 ,  11  (i.e., interconnecting the first and second conveyance paths) is not substantially bent or curved. Therefore, the sheet can be conveyed from the first conveyor  203  to the second conveyor  11 , without the sheet receiving a large convey resistance, which is a force applied to the sheet and acting in a direction opposite to the conveyance direction. Therefore, even if the recording is being carried out by the first recording head  219  when the sheet is conveyed from the first conveyor  203  to the second conveyor  11 , it is possible to avoid deterioration of quality of the recoded image, which could be caused if the velocity of the conveyed sheet were momentarily reduced by a large amount. 
     On the other hand, when the belt conveyor unit  204  takes the second angular posture, as shown in  FIG. 7 , the supporting surface  208  of the conveyor belt  207  is inclined so as to extend in a right downward direction. Since the conveyor belt  207  attracts the sheet thereto while conveying the sheet, the sheet is attracted onto the supporting surface  208  of the conveyor belt  207 , so that the sheet can be reliably conveyed by the conveyor belt  207 , although the supporting surface  208  of the conveyor belt  207  constitutes a downslope surface, i.e., a slope surface that is inclined such that the slope surface has a height that is reduced in the first conveyance direction. That is, when the sheet is transferred from the conveyor belt  205  to the conveyor belt  207 , the sheet is caused to be attracted onto the supporting surface  208  of the conveyor belt  207  upon arrival of the leading end portion of the sheet at the conveyor belt  207 , so that the direction of conveyance the sheet is changed by the attraction of the sheet onto the supporting surface  208  of the conveyor belt  207 . Therefore, as compared with an arrangement in which the direction of conveyance of the sheet is changed by a pivotable flapper that does not apply a conveying force to the sheet, it is possible to reduce the conveyance resistance applied to the sheet. In the arrangement with the pivotable flapper, the conveyance direction is abruptly changed upon collision of the leading end of the sheet with the flapper, thereby resulting in a large convey resistance that is momentarily applied to the sheet. However, in the present second embodiment in which the conveyance direction is changed owing to the attraction of the sheet onto the supporting surface  208  of the conveyor belt  207 , a large convey resistance is not applied to the sheet. 
     In the present second embodiment, the direction of conveyance of the sheet is changed by the attraction of the leading end portion of the sheet onto the supporting surface  208  of the conveyor belt  207 . Consequently, as compared with an arrangement with the pivotable flapper, the convey resistance applied to the sheet can be made smaller. Accordingly, even if the recording is being continuously carried out by the first recording head  219  when the sheet is conveyed from the first conveyor  203  to the second conveyor  11 , it is possible to avoid deterioration of quality of the recoded image. 
     &lt;Modifications of Second Embodiment&gt; 
     In the above-described second embodiment, the first conveyor  203  includes two conveyor units in the form of the belt conveyor units  202 ,  204 . However, this arrangement is not essential. For example, the first conveyor  203  may include, in place of the belt conveyor units  202 ,  204 , pairs of conveying rollers and a platen for supporting a sheet. Further, in the above-described second embodiment, the conveyor belt  205  is configured to convey a sheet while causing the sheet to be attracted onto the supporting surface  206  of the conveyor belt  205 . However, this arrangement is not essential. 
     In the above-described second embodiment, the belt conveyor units  202 ,  204  include attraction generating devices which are constituted by the belt pulleys  209 ,  211 , first and second charge rollers and first and second direct-current sources and which are configured to provide the conveyor belts  205 ,  207  with the attraction forces each of which is generated based on a static electricity. However, this arrangements is not essential. For example, a pair of comb-teeth-like electrodes may be disposed on a surface of each of the platens  215 ,  217  which is in contact with a corresponding one of the conveyor belts  205 ,  207 , wherein the comb-teeth-like electrodes are spaced apart from each other by a given distance, for avoiding a short connection between the electrodes. Each of the comb-teeth-like electrodes has a plurality of elongated portions which are elongated in the right-left direction and which are arranged in the front-rear direction. In this modification, with application of an electric voltage between the comb-teeth-like electrodes, an attraction force based on a static electricity can be generated in the conveyor belts  205 ,  207 . 
     In the above-described second embodiment, each of the conveyor belts  205 ,  207  is given the attraction force based on the static electricity, whereby a sheet is caused to be attracted onto a corresponding one of the supporting surfaces  206 ,  208 . However, this arrangement is not essential. For example, each of the conveyor belts  205 ,  207  may be constituted by a belt having self-bonding properties, so that a sheet can be attracted to the belt owing to the self-bonding properties. Further, as another example, a sucking device may be provided for sucking air through holes that are formed through the conveyor belts  205 ,  207 , for thereby enabling a sheet to be attracted to the conveyor belts  205 ,  207 , owing to a sucking force that is generated by the sucking device. 
     In the above-described second embodiment, the conveyor belts  205 ,  207  are stretched around the belt pulleys  209 ,  210 ,  211 ,  212 , and the upstream-side belt pulleys  209 ,  211  serve as drive rollers. However, the downstream-side belt pulleys  210 ,  212 , in place of the upstream-side belt pulleys  209 ,  211 , may serve as drive rollers. 
     In the above-described second embodiment, there is not provided a pressing roller serving to press a sheet onto the outer circumferential surface of the conveyor belt  207 . However, a freely rotatable roller may be provided as such a pressing roller. In this modification, although the sheet, which has been transferred from the conveyor belt  205  to the conveyor belt  207 , is likely to collide at its leading end portion with the pressing roller, it is possible to restrain the convey resistance applied to the sheet because the pressing roller is constituted by a freely rotatable roller. 
     In the above-described second embodiment, when the conveyor belt  207  takes the first angular posture, the supporting surfaces  208 ,  60  of the respective conveyor belts  207 ,  59  are substantially flush with each other. However, in this instance, the second conveyor  11  may be located either on an upper side or a lower side of the conveyor belt  207 . In this modification, too, the first angular posture of the first conveyor  7  is an angular posture of the conveyor belt  207  by which the first conveyance path (defined by the supporting surfaces  206 ,  208  of the respective conveyor belts  205 ,  207 ) is directed to the second conveyance path (defined by the supporting surface  60  of the conveyor belt  59 ). Further, in the above-described second embodiment, the third conveyor  15  is located on a lower side of the conveyor belt  207 . However, the third conveyor  15  may be located on an upper side of the conveyor belt  207  or located in the same height position as the conveyor belt  207 . In this modification, too, the second angular posture of the conveyor belt  207  is an angular posture of the conveyor belt  207  by which the first conveyance path (defined by the supporting surfaces  206 ,  208  of the respective conveyor belts  205 ,  207 ) is directed to the third conveyance path (defined by the conveying guides  71 ,  73 ). It is noted that, where the third conveyor  15  is located in the same height position as the conveyor belt  207 , the supporting surface  208  of the conveyor belt  207  is substantially flush with the conveying guides  71 ,  73 .