Patent Publication Number: US-10308045-B2

Title: Sheet conveyor and ink-jet recording apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Japanese Patent Application No. 2016-016741, which was filed on Jan. 29, 2016, the disclosure of which is herein incorporated by reference in its entirety. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a sheet conveyor configured to convey a sheet supported by a support portion or a sheet supporter and relates to an ink-jet recording apparatus equipped with the sheet conveyor. 
     Description of Related Art 
     There have been known sheet conveyors having a configuration for conveying a sheet with high accuracy. For instance, a recording apparatus (a sheet conveyor) having a recording unit and a sheet supply unit is known. The recording unit includes a conveyance roller. The sheet supply unit includes a supply roller. A sheet supplied from a supply tray by the supply roller is conveyed by the conveyance roller. The recording unit and the sheet supply unit are fixed, at opposite end portions thereof in a direction perpendicular to a conveyance direction, to a pair of side chassis. In the recording apparatus, the position of the supply roller is fixed. A pressure plate on which a sheet is placed is urged toward the supply roller, whereby the supply roller comes into contact with the surface of the sheet. 
     Further, a sheet conveyor having a pendulum supply roller is known. The sheet conveyor includes a supply roller supported by a pivotable arm. The supply roller is urged toward a sheet supported on a supply tray. 
     SUMMARY 
     In the sheet conveyor including the pendulum supply roller, it is preferable that parallelism between a pivot axis of the arm and a rotation axis of the conveyance roller be maintained, for instance. To this end, it is necessary that positional relationship between the two axes is kept accurate. If the positional relationship between the two axes are not accurate and the parallelism therebetween is not maintained, there may be a risk that the sheet conveyed by the supply roller and the conveyance roller may be skewed. 
     The present disclosure provides a sheet conveyor having a pendulum supply roller in which skewing of sheets is prevented. 
     In one aspect of the disclosure, a sheet conveyor includes: a shaft defining an axis that extends in a first direction; an arm pivotable about the axis; a supply roller provided on the arm and configured to supply a sheet; a first frame formed of metal and supporting the shaft; a first conveyance roller configured to covey the sheet supplied from the supply roller; and a second frame formed of metal and supporting the first conveyance roller, wherein the second frame includes (a) a contact plate portion shaped like a plate and having a contact surface that is held in contact with the first frame and (b) a wall portion extending from the contact plate portion in a direction intersecting the contact surface, and wherein the second frame is coupled at the contact plate portion thereof to the first frame. 
     In another aspect of the disclosure, a sheet conveyor includes: a shaft defining an axis that extends in a first direction; an arm pivotable about the axis; a supply roller provided on the arm and configured to supply a sheet; a first frame formed of metal and supporting the shaft; a first conveyance roller configured to covey the sheet supplied from the supply roller; and a second frame formed of metal and supporting the first conveyance roller, wherein the second frame includes a contact plate having a contact surface that is held in contact with the first frame, the second frame being bent at the contact plate in a direction intersecting the contact surface, and wherein the second frame is coupled at the contact plate thereof to the first frame. 
     In still another aspect of the disclosure, an ink-jet recording apparatus includes: a recording head; a carriage on which the recording head is mounted; a guide rail holding the carriage such that the carriage reciprocates along the first direction; and the sheet conveyor constructed as described above, wherein the guide rail is supported by the second frame. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects, features, advantages, and technical and industrial significance of the present disclosure will be better understood by reading the following detailed description of an embodiment, when considered in connection with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an MFP; 
         FIG. 2  is an elevational view in vertical cross section schematically showing an internal structure of the MFP; 
         FIG. 3  is a perspective view showing a state in which a guide rail, a frame, and a supply frame are assembled; 
         FIG. 4A  is a plan view schematically showing a contact plate portion of the frame,  FIG. 4B  is a plan view schematically showing a protruding portion of the supply frame, and  FIG. 4C  is a cross-sectional view taken along line A-A in  FIG. 4B  showing a state in which a lower surface of the contact plate portion and an upper surface of the protruding portion which are held in contact with each other are screwed to a lower cover; 
         FIG. 5  is a perspective view showing the guide rail, the frame, the supply frame, and the lower cover; 
         FIG. 6  is a perspective view showing a state in which a mechanism for conveying a sheet is attached to the guide rails, the frame, and the supply frame; 
         FIG. 7A  is a cross-sectional view taken along line A-A in  FIG. 6  and  FIG. 7B  is a cross-sectional view taken along line B-B in  FIG. 6 ; and 
         FIG. 8  is a plan view schematically showing a supply roller. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT 
     Referring to the drawings, there will be described one embodiment. It is to be understood that the following embodiment is described only by way of example, and the disclosure may be otherwise embodied without departing from the scope of the disclosure. A multi-functional peripheral (MFP)  10  of the present embodiment is used in a state shown in  FIG. 1 . In the present embodiment, an up-down direction  7  is defined with respect to this state. Further, a front-rear direction  8  (as one example of a second direction) is defined by regarding a side of the MFP  10  in which an opening  13  is formed as a front side, and a right-left direction  9  (as one example of a first direction) is defined in a state in which the MFP  10  is viewed from the font side. 
     As shown in  FIG. 1 , the MFP  10  (as one example of an ink-jet recording apparatus and a sheet conveyor) has a housing  14  shaped like a generally rectangular parallelepiped. A printer  11  of an ink-jet recording type is provided in a lower portion of the housing  14 . The MFP  10  has various functions such as a facsimile function and a printing function. One example of the printing function of the MFP  10  is a double-sided image recording function for recording images on both sides of a recording sheet  16  ( FIG. 2 ). It is noted that functions of the MFP  10  other than the printing function are optional. The opening  13  is formed on the front side of the housing  14 . A supply tray  20 , on which the recording sheets  16  of various sizes can be stacked, is insertable and removable through the opening  13  in the front-rear direction  8 . In other words, the supply tray  20  is mountable on and removable from the MFP  10 . 
     Structure of Printer  11   
     As shown in  FIG. 2 , the printer  11  includes: a sheet supplying portion  15  configured to supply one of the recording sheets  16  stacked on the supply tray  20 ; a recording portion  24  of an ink-jet recording type disposed above the supply tray  20  and configured to record an image on the recording sheet  16  supplied by the sheet supplying portion  15  by ejecting ink droplets onto the recording sheet  16 ; and a path switcher  41 . In the present embodiment, the recording portion  24  is of an ink-jet recording type. The recording portion  24  may be of other types such as an electrophtographic type. 
     Sheet Supplying Portion  15   
     As shown in  FIG. 2 , the sheet supplying portion  15  is provided above the supply tray  20  and below the recording portion  24 . The sheet supplying portion  15  includes a supply roller  25 , a supply arm  26  (as one example of an arm), and a drive-force transmitting mechanism  27 . The supply roller  25  is rotatably supported at a distal end portion of the supply arm  26 . The supply roller  25  is constituted by two rollers  34 ,  35  spaced apart from each other in the right-left direction  9  ( FIG. 8 ). The supply arm  26  pivots, in directions indicated by an arrow  29  in  FIG. 2 , about a pivot shaft  28  (as one example of a shaft) provided at a proximal end portion of the supply arm  26  and defining an axis of a pivotal movement of the supply arm  26 . This axis extends in the right-left direction  9 , namely, a direction perpendicular to the sheet plane of  FIG. 2 . This construction allows the supply roller  25  to be moved toward and away from the supply tray  20 . In other words, the supply roller  25  can be brought into contact with an uppermost one of the recording sheets  16  stacked on the supply tray  20 . The supply roller  25  is rotated by a drive force generated by a supply motor (not shown) and transmitted by the drive-force transmitting mechanism  27  constituted by a plurality of gears ( FIG. 7 ) meshing with one another. In a state in which the supply roller  25  is in contact with the uppermost one of the recording sheets  16  stacked on the supply tray  20 , the supply roller  25  separates the uppermost sheet  16  from other sheets  16 , so as to supply the separated sheet  16  to a first curved path  65 A. The supply arm  26  will be later described in detail. 
     Conveyance Path  65   
     As shown in  FIG. 2 , the conveyance path  65  (as one example of a first conveyance path) is formed in the printer  11 . The conveyance path  65  extends from a rear end of the supply tray  20  to a discharge tray  79  via the recording portion  24 . The conveyance path  65  has: the first curved path  65 A formed between the rear end of the supply tray  20  and the recording portion  24 ; and a discharge path  65 B formed between the recording portion  24  and the discharge tray  79 . 
     The first curved path  65 A is a curved path extending from near an upper end of an inclined sheet separator plate  22  provided on the supply tray  20  to the recording portion  24 . The first curved path  65 A has a generally arc shape whose center of curvature is located on an inner side of the printer  11 . The recording sheet  16  supplied from the supply tray  20  is guided just under the recording portion  24  after having made a U-turn along the first curved path  65 A in a first conveyance direction  48 , namely, in a direction indicated by the long dashed short dashed line with arrows in  FIG. 2 . The first curved path  65 A is defined by an outer guide member  18  and an intermediate guide member  17  which are opposed to each other with a predetermined distance interposed therebetween. The outer guide member  18 , the intermediate guide member  17 , and guide members  19 ,  31 ,  32 ,  33 ,  52 ,  53 , which will be later described, extend in the direction perpendicular to the sheet plane of  FIG. 2 , i.e., the right-left direction  9  in  FIG. 1 . 
     The discharge path  65 B is a straight path extending from just under the recording portion  24  to the discharge tray  79 . The recording sheet  16  is guided by the discharge path  65 B in the first conveyance direction  48 . In a region in which the recording portion  24  is disposed, the discharge path  65 B is defined by the recording portion  24  and a platen  42  which are opposed to each other with a predetermined distance interposed therebetween. In a region in which the recording portion  24  is not disposed, the discharge path  65 B is defined by an upper guide member  52  and a lower guide member  53  which are opposed to each other with a predetermined distance interposed therebetween. 
     A branch position  36  is located downstream of the recording portion  24  in the first conveyance direction  48 . In double-sided image recording, a moving direction of the recording sheet  16  conveyed along the discharge path  65 B is reversed on the downstream side of the branch position  36 , and then the recording sheet  16  is conveyed toward a switchback conveyance path  67  which will be explained. 
     Recording Portion  24   
     As shown in  FIG. 2 , the recording portion  24  is disposed above the supply tray  20 . The recording portion  24  reciprocates in the right-left direction  9 , namely, in the direction perpendicular to the sheet plane of  FIG. 2 . The platen  42  for horizontally holding the recording sheet  16  is provided below the recording portion  24 . The recording portion  24  is disposed so as to be opposed to the platen  42  in the up-down direction  7 . The recording portion  24  includes a carriage  23  and a recording head  39 . 
     The carriage  23  is supported by guide rails  43 ,  44  ( FIG. 6 ) spaced apart from each other in the front-rear direction  8  and extending in the right-left direction  9 . As shown in  FIG. 6 , the guide rails  43 ,  44  are attached to a frame  80  (as one example of a second frame). The carriage  23  is coupled to a known belt drive mechanism (not shown) provided on the guide rail  44 . The guide rails  43 ,  44  will be described later. 
     As shown in  FIG. 2 , the recording head  39  is mounted on the carriage  23 . A plurality of nozzles (not shown) are formed in a lower surface of the recording head  39 . The recording head  39  ejects, from the nozzles, ink supplied from an ink cartridge (not shown) to the recording sheet  16  conveyed on the platen  42  during the reciprocating movement of the carriage  23  in the right-left direction  9 . Thus, an image is recorded on the recording sheet  16  conveyed through the conveyance path  65 . 
     Conveyance Roller  60 , Discharge Roller  62 , and Bidirectional Conveyance Roller  45   
     As shown in  FIG. 2 , a conveyance roller  60  (as one example of a first conveyance roller) and a pinch roller  61  are provided between: downstream ends of the outer guide member  18  and the intermediate guide member  17  in the first conveyance direction  48 ; and the recording portion  24 . A rotation shaft  60 A of the conveyance roller  60  is rotatably supported by the frame  80 . The pinch roller  61  is disposed under the conveyance roller  60  and is held in pressing contact with a roller surface of the conveyance roller  60  by an elastic member such as a spring (not shown). The conveyance roller  60  and the pinch roller  61  nip the recording sheet  16  conveyed through the first curved path  65 A and convey the recording sheet  16  onto the platen  42 . 
     A discharge roller  62  and a spur  63  are provided between: the recording portion  24 ; and the upper guide member  52  and the lower guide member  53 . The spur  63  is disposed over the discharge roller  62  and is held in pressing contact with a roller surface of the discharge roller  62  by an elastic member such as a spring (not shown). The discharge roller  62  and the spur  63  nip the recording sheet  16  on which an image has been recorded by the recording portion  24  and convey the image-recorded sheet  16  to a downstream side in the first conveyance direction  48 . 
     The conveyance roller  60  and the discharge roller  62  are rotated by a rotational drive force transmitted from a conveyance motor. The conveyance roller  60  and the discharge roller  62  rotate forwardly and reversely in accordance with rotation of the conveyance motor. The forward rotation of the conveyance roller  60  and the discharge roller  62  causes the recording sheet  16  to be conveyed in the first conveyance direction  48 . 
     A bidirectional conveyance roller  45  and a spur  46  are provided downstream of the branch position  36  in the first conveyance direction  48 . The spur  46  is urged downward in the up-down direction  7  by an elastic member such as a spring and is held in pressing contact with a roller surface of the bidirectional conveyance roller  45 . 
     The bidirectional conveyance roller  45  is rotated forwardly by a forward drive force transmitted from the conveyance motor and is rotated reversely by a reverse drive force transmitted from the conveyance motor. In single-sided recording, for instance, the bidirectional conveyance roller  45  is rotated forwardly, so that the recording sheet  16  nipped by the bidirectional conveyance roller  45  and the spur  46  is conveyed downstream and is discharged onto the discharge tray  79 . In double-sided recording, for instance, the rotational direction of the bidirectional conveyance roller  45  is switched from the forward direction to the reverse direction in a state in which the bidirectional conveyance roller  45  and the spur  46  nip a trailing end of the recording sheet  16 . As a result, the recording sheet  16  is conveyed in a direction opposite to the first conveyance direction  48  and is conveyed toward the switchback conveyance path  67  by the path switcher  41 . 
     Switchback Conveyance Path  67   
     As shown in  FIG. 2 , the switchback conveyance path  67  (as one example of a second conveyance path) is connected to the conveyance path  65  at the branch position  36  of the discharge path  65 B and at a merge position  37  of the first curved path  65 A located upstream of the recording portion  24  in the first conveyance direction  48 . The recording sheet  16  is conveyed through the switchback conveyance path  67  in a second conveyance direction  49 . The second conveyance direction  49  is a direction in which the recording sheet  16  is conveyed through the switchback conveyance path  67  from the branch position  36  toward the merge position  37 , as indicated by the long dashed double-short dashed line with arrows in  FIG. 2 . 
     The switchback conveyance path  67  includes: a straight portion that extends from the branch position  36  along the second conveyance direction  49  rearward and downward; and a curved portion that is curved upward. An upper part of the straight portion and an inner part of the curved portion of the switchback conveyance path  67  are defined by a second guide member  32  ( FIG. 7 ) and the inner guide member  19  ( FIG. 7 ) while a lower part of the straight portion and an outer part of the curved portion of the switchback conveyance path  67  are defined by a first guide member  31  ( FIG. 7 ), a third guide member  33 , and the intermediate guide member  17 . 
     Conveyance Roller  68   
     A conveyance roller  68  (as one example of a second conveyance roller) and a driven roller  69  are provided in the switchback conveyance path  67 . The driven roller  69  is disposed below the recording portion  24  and over the conveyance roller  68 . As shown in  FIG. 7B , the conveyance roller  68  is supported by a rear end portion of a conveyance arm  74  which is supported by a stationary portion  111  of the supply arm  26 . The driven roller  69  is rotatably supported by the second guide member  32 . 
     The conveyance roller  68  is disposed under the driven roller  69 . The switchback conveyance path  67  is interposed between the conveyance roller  68  and the driven roller  69  in the up-down direction  7 . The conveyance roller  68  is held in pressing contact with a roller surface of the driven roller  69  by a coil spring (not shown). 
     The conveyance roller  68  is rotated forwardly by a forward drive force transmitted from the supply motor (not shown). A conveyance roller pair  70  constituted by the conveyance roller  68  and the driven roller  69  is configured such that, when the supply motor forwardly rotates, the conveyance roller  68  and the driven roller  69  nip the recording sheet  16  conveyed through the switchback conveyance path  67  and convey the recording sheet  16  in the second conveyance direction  49 . 
     Lower Cover  12   
     As shown in  FIG. 5 , the MFP  10  has a box-like lower cover  12 . The lower cover  12  is a part of the housing  14  and forms a bottom surface of the MFP  10 , etc. The lower cover  12  defines therein a space  12 A opening upward and located at a central portion of the lower cover  12  in the front-rear direction  8  and the right-left direction  9 . The supply tray  20  described above is disposed in the space  12 A. The lower cover  12  is formed of resin. 
     Guide Rails  43 ,  44   
     As shown in  FIG. 6 , each of the guide rails  43 ,  44  extends along a plane defined by the front-rear direction  8  and the right-left direction  9 . Each of the guide rails  43 ,  44  is a flat plate having a generally rectangular shape that is long in the right-left direction  9 . The guide rail  44  is located forward of and at a height position lower than the guide rail  43  ( FIG. 7 ). Each of the guide rails  43 ,  44  is formed by sheet metal working of a metal plate. Each of the guide rails  43 ,  44  has through-holes (not shown) penetrating therethrough in the up-down direction  7  and formed at respective opposite end portions in the right-left direction  9 . Positions of the through-holes of the guide rail  43  correspond to positions of first engaging portions  91  of the frame  80  which will be explained. Positions of the through-holes of the guide rail  44  correspond to positions of second engaging portions  92  of the frame  80  which will be explained. 
     As shown in  FIG. 6 , each of the guide rails  43 ,  44  is bent upward at its opposite ends in the front-rear direction  8 . Thus, each guide rail  43 ,  44  is prevented from being deformed such that its central portion in the right-left direction  9  is displaced in the up-down direction  7  or the front-rear direction  8  with respect to its opposite end portions in the right-left direction  9 . 
     Frame  80   
     As shown in  FIG. 3 , the MFP  10  includes the frame  80 . The frame  80  is located below the guide rails  43 ,  44  ( FIG. 7 ). As shown in  FIG. 3 , the frame  80  is a flat rectangular plate extending along the plane defined by the front-rear direction  8  and the right-left direction  9 . The frame  80  is produced by sheet metal working of a metal plate. 
     As shown in  FIG. 3 , the frame  80  includes a flat plate portion  81 , right and left contact plate portions  82 , right and left wall portions  83 , a front extending portion  84 , and a vertical plate portion  85 . 
     The flat plate portion  81  is flat rectangular plate disposed along the plane defined by the front-rear direction  8  and the right-left direction  9 . The flat plate portion  81  has a pair of right and left through-holes  90  penetrating therethrough in the up-down direction  7 . The through-holes  90  are formed at a rear end portion of the flat plate portion  81  so as to be located respectively at opposite ends in the right-left direction  9 . Each through-hole  90  is longer in the right-left direction  9 . Screws are inserted in the through-holes  90  for screwing the frame  80  to the lower cover  12 . 
     The contact plate portions  82  extend forward from opposite ends in the right-left direction  9  of a front end of the flat plate portion  81 . That is, two contact plate portions  82  are provided so as to be spaced apart from each other in the right-left direction  9 . Each contact plate portion  82  is a flat rectangular plate extending along the plane defined by the front-rear direction  8  and the right-left direction  9 . A lower surface  82 A ( FIG. 4C ) of each contact plate portion  82  is a flat surface extending along the plane defined by the front-rear direction  8  and the right-left direction  9 . The lower surface  82 A of the contact plate portion  82  is one example of a contact surface. Positions of the lower surfaces  82 A of the contact plate portions  82  correspond to positions of protruding portions  103  of a supply frame  100  (as one example of a first frame) which will be explained. 
     As shown in  FIG. 4A , each contact plate portion  82  has two through-holes  86 ,  87  which penetrate therethrough in the up-down direction  7  and which are spaced apart from each other in the front-rear direction  8 . The through-hole  86  is a circular through-hole and is used for fixing the supply frame  100  and the frame  80  to the lower cover  12 . The through-hole  87  is located forward of the through-hole  86 . The through-hole  87  is longer in the right-left direction  9 . A protrusion  106  of the supply frame  100  is inserted into the through-hole  87  from below. 
     As shown in  FIG. 3 , each wall portion  83  extends upward from a corresponding one of opposite ends of the flat plate portion  81  in the right-left direction  9  and a corresponding one of opposite ends of each contact plate portion  82  in the right-left direction  9 . The wall portion  83  is a flat rectangular plate extending in the right-left direction  9 . The wall portion  83  extends from a front end of the contact plate portion  82  to beyond a rear end of the flat plate portion  81 . 
     A pair of right and left rotation-shaft support portions  88  and a pair of right and left rotation-shaft support portions  89  are formed in the wall portions  83 . The rotation-shaft support portions  88  are located at a position which is rearward of a central part of each wall portion  83  in the front-rear direction  8  and which corresponds to the rear end of the flat plate portion  81 . An upper end of a rear end portion of the wall portion  83  is located at a height level higher than an upper end of a front end portion thereof, so that a stepped portion is formed therebetween. The rotation-shaft support portion  88  is a recess which is formed at the stepped portion so as to be recessed backward. In the rotation-shaft support portions  88 , there is received a bearing which rotatably supports the rotation shaft  60 A ( FIG. 2 ) of the conveyance roller  60 . The rotation shaft  60 A of the conveyance roller  60  is supported by the bearing. 
     As shown in  FIG. 3 , the rotation-shaft support portions  89  are located at the front end portion of the wall portions  83 . Each wall portion  83  has, at its front end portion, two protruding portions  93 ,  94  spaced apart from each other in the front-rear direction  8 . The rotation-shaft support portion  89  is a recess which is formed between the protruding portions  93 ,  94  so as to be recessed downward and rearward from the upper end of the wall portion  83 . In the rotation-shaft support portion  89 , there is received a bearing which rotatably supports a rotation shaft  62 A ( FIG. 2 ) of the discharge roller  62 . The rotation shaft  62 A of the discharge roller  62  is supported by the bearing. 
     Each of the two wall portions  83  includes the first engaging portion  91  and the second engaging portion  92 . 
     As shown in  FIG. 3 , the first engaging portion  91  protrudes upward from an upper end of each wall portion  83  on the back side of the rotation-shaft support portion  88  and the vertical plate portion  85 . As shown in  FIGS. 7A and 7B , the first engaging portion  91  is a flat rectangular plate extending along a plane defined by the up-down direction  7  and the front-rear direction  8 . The first engaging portion  91  has a through-hole  91 A formed therethrough in the right-left direction. The through-hole  91 A is longer in the front-rear direction  8 . The positions of the first engaging portions  91  correspond to the positions of the through-holes (not shown) of the guide rail  43 . The guide rail  43  is positioned with respect to the front-rear direction  8  and the right-left direction  9  by engagement of the guide rail  43  and the first engaging portions  91 . Further, the guide rail  43  is positioned with respect to the up-down direction  7  by contact of the lower surface of the guide rail  43  and the upper ends of the wall portions  83 . 
     As shown in  FIG. 5 , the second engaging portion  92  is formed at both of the protruding portion  93  and the protruding portion  94 . A second engaging portion  92 A formed at the protruding portion  93  has a hook-like shape that protrudes upward from an upper end of the protruding portion  93  and is bent forward. A second engaging portion  92 B of the protruding portion  94  has a hook-like shape that protrudes upward from an upper end of the protruding portion  94  and is bent rearward. The positions of the second engaging portions  92  correspond to the positions of the through-holes (not shown) of the guide rail  44 . The guide rail  44  is positioned with respect to the front-rear direction  8  and the right-left direction  9  by engagement of the guide rail  44  and the second engaging portions  92 . Further, the guide rail  44  is positioned with respect to the up-down direction  7  by contact of the lower surface of the guide rail  44  and the upper ends of the wall portions  83 . 
     As shown in  FIG. 3 , the front extending portion  84  is located on an inner side of the contact plate portions  82  in the right-left direction  9 . The front extending portion  84  extends upward from a front end of the flat plate portion  81  so as to have an L-like bent shape ( FIG. 7 ). The front extending portion  84  defines an upper end of a part of the switchback conveyance path  67 . Owing to the front extending portion  84 , the frame  80  is prevented from being deformed such that its central portion in the right-left direction  9  is displaced in the up-down direction  7  or the front-rear direction  8  with respect to its opposite end portions in the right-left direction  9 . 
     As shown in  FIG. 3 , the vertical plate portion  85  is located on an inner side of the wall portions  83  in the right-left direction  9 . The vertical plate portion  85  extends upward from the rear end of the flat plate portion  81  and extends in the right-left direction  9 . Owing to the vertical plate portion  85 , the frame  80  is prevented from being deformed such that its central portion in the right-left direction  9  is displaced in the up-down direction  7  or the front-rear direction  8  with respect to its opposite end portions in the right-left direction  9 . 
     Supply Frame  100   
     As shown in  FIG. 3 , the supply frame  100  is located forward of the frame  80  and below the guide rail  44  ( FIG. 7 ). As shown in  FIG. 3 , the supply frame  100  is a flat rectangular plate extending along the plane defined by the front-rear direction  8  and the right-left direction  9 . The supply frame  100  is produced by sheet metal working of a metal plate. 
     The supply frame  100  includes a horizontal plate portion  101 , a vertical plate portion  102 , and projecting portions  104 . 
     The horizontal plate portion  101  is a flat rectangular plate extending along the plane defined by the front-rear direction  8  and the right-left direction  9 . As shown in  FIG. 7 , an opening  121  is formed at a position which is between the horizontal plate portion  101  and the front extending portion  84  of the frame  80  and which is between the two contact plate portions  82  ( FIG. 3 ). The opening  121  is defined by an upper surface  101 A of a rear end portion of the horizontal plate portion  101  and a lower surface  84 A of the front extending portion  84 . The recording sheet  16  guided by the switchback conveyance path  67  passes through the opening  121 . 
     As shown in  FIG. 5 , the horizontal plate portion  101  has protruding portions  103  at respective opposite ends thereof in the right-left direction  9 . Each protruding portion  103  has a generally rectangular shape. As shown in  FIG. 4C , the protruding portion  103  protrudes upward so as to have a height higher than other portion of the horizontal plate portion  101 . As shown in  FIG. 4B , the protruding portion  103  includes a circular through-hole  105  penetrating therethrough in the up-down direction  7  and a circular protrusion  106  located forward of the through-hole  105  and protruding upward. As shown in  FIG. 4C , an upper surface  103 A of the protruding portion  103  is a flat surface extending along the plane defined by the front-rear direction  8  and the right-left direction  9 . The upper surfaces  103 A of the protruding portions  103  are held in contact with the lower surfaces  82 A of the contact plate portions  82  of the frame  80 , whereby the supply frame  100  is positioned with respect to the frame  80  in the up-down direction  7 . In a state in which the protrusions  106  are inserted in the through-holes  87  of the contact plate portions  82 , the frame  80  and the supply frame  100  are screwed to the lower cover  12  by screws inserted into the through-holes  105  of the protruding portions  103  of the supply frame  100  and the through-holes  86  of the contact plate portions  82  of the frame  80 . Thus, the supply frame  100  is positioned with respect to the frame  80  in the front-rear direction  8  and the right-left direction  9 . In the present embodiment, the through-hole  87  has a larger dimension in the right-left direction  9  than in the front-rear direction  8  for allowing tolerances of the frame  80  and the supply frame  100  in the right-left direction  9  and for holding the shafts of the rollers supported by the frame  80  and the supply frame  100  so as to be parallel to each other. 
     As shown in  FIG. 3 , the vertical plate portion  102  extends in a downward direction (as one example of a direction perpendicular to the first direction), from an entire region at a front end portion of the horizontal plate portion  101  in the right-left direction  9 . Owing to the vertical plate portion  102 , the supply frame  100  is prevented from being deformed such that its central portion in the right-left direction  9  is displaced in the up-down direction  7  with respect to its opposite end portions in the right-left direction  9 . 
     A plurality of through-holes  107  are formed in the vertical plate portion  102  in a region thereof located inward of the protruding portions  103  in the right-left direction  9 . The through-holes  107  are formed through the vertical plate portion  102  in the front-rear direction  8  and are spaced apart from each other in the right-left direction  9 . The supply arm  26  is screwed to the supply frame  100  by screws inserted into the through-holes  107 . 
     The pair of projecting portions  104  are provided at opposite end portions of the vertical plate portion  102  in the right-left direction  9 , so as to be located forward of the corresponding protruding portions  103 . Each projecting portion  104  projects forward from the vertical plate portion  102 . Each projecting portion  104  is a flat rectangular plate extending along the plane defined by the front-rear direction  8  and the right-left direction  9 . Each projecting portion  104  has a through-hole  108  formed therethrough in the up-down direction  7  at a central portion thereof in the front-rear direction  8  and the right-left direction  9 . The supply frame  100  is screwed to the lower cover  12  by screws inserted in the through-holes  108 . 
     Supply Arm  26   
     As shown in  FIG. 7 , the supply arm  26  includes a stationary portion  111  and a pivotable portion  112 . 
     The stationary portion  111  has a rectangular parallelepiped shape that is long in the right-left direction  9 . The stationary portion  111  has an inner space for supporting the pivot shaft  28 . The pivotable portion  112  extends from the stationary portion  111  rearward and downward and has a suitable dimension in the right-left direction  9 . The pivotable portion  112  is shaped like a box opening upward. As shown in  FIG. 7 , a front end portion of the stationary portion  111  is in contact with the vertical plate portion  102  from the rear side in the region of the supply frame  100  located inward of the protruding portions  103  in the right-left direction  9  ( FIG. 3 ). In this state, the stationary portion  111  is fixed to the supply frame  100  by screws  122  inserted in the through-holes  107  of the vertical plate portion  102  of the supply frame  100 . 
     As shown in  FIG. 7B , the stationary portion  111  has a shaft support portion  113 . The shaft support portion  113  is located at the front end portion of the stationary portion  111 . The shaft support portion  113  pivotally supports: the pivot shaft  28  that pivotally supports a front end  112 A of the pivotable portion  112 ; and a conveyance drive shaft  132  that pivotally supports the conveyance arm  74 . With this construction, the pivotable portion  112  and the conveyance arm  74  are pivotally supported by the stationary portion  111 . 
     The MFP  10  includes a supply drive shaft  131  and the conveyance drive shaft  132 . 
     As shown in  FIG. 7B , the supply drive shaft  131  is located at a front end portion of the supply arm  26 . The supply drive shaft  131  extends in the right-left direction  9 , namely, in the direction perpendicular to the sheet plane of  FIG. 7B . The supply drive shaft  131  is supported by the stationary portion  111 . The supply drive shaft  131  is rotated by a drive force generated by the supply motor (not shown). A pendulum gear  134  is in mesh with a gear  131 A configured to rotate with the supply drive shaft  131 . The pendulum gear  134  is supported by an arm  135  which is coaxial with the gear  131 A. Depending upon the rotational direction of the supply drive shaft  131 , the pendulum gear  134  is selectively placed in a meshed state in which the pendulum gear  134  is in mesh with a gear  28 A of the drive-force transmitting mechanism  27  and a non-meshed state in which the pendulum gear  134  is spaced apart from the gear  28 A. The drive-force transmitting mechanism  27  is constituted by a gear train including the gear  28 A and other gears. A drive force is transmitted from the gear  28 A to the supply roller  25  by the drive-force transmitting mechanism  27 , so that rotation of the supply drive shaft  131  is transmitted to the supply roller  25 . Consequently, rotation of the supply motor in one of opposite directions causes the supply roller  25  to be rotated while rotation of the supply motor in the other of the opposite directions does not cause the supply roller  25  to be rotated. 
     As shown in  FIG. 7B , the stationary portion  111  supports the conveyance arm  74 . The conveyance drive shaft  132  defines a pivot axis of the conveyance arm  74 . The conveyance drive shaft  132  extends in the right-left direction  9 , namely, in the direction perpendicular to the sheet plane of  FIG. 7B . The conveyance drive shaft  132  is rotated by the drive force generated by the supply motor (not shown). The rotation of the conveyance drive shaft  132  is transmitted to the conveyance roller  68  by a gear  133  attached to the conveyance drive shaft  132 . Thus, the conveyance roller  68  is rotated by the drive force generated by the supply motor. 
     Assembling of Frame  80  and Supply Frame  100   
     As shown in  FIG. 6 , the first engaging portions  91  of the frame  80  are inserted into the through-holes (not shown) of the guide rail  43  from below, and pins  123  are fitted into the through-holes  91 A of the first engaging portions  91 . Thus, the guide rail  43  is engaged with the frame  80 . 
     The second engaging portions  92  of the frame  80  are inserted into the through-holes (not shown) of the guide rail  44  from below, and the hook of the front-side second engaging portion  92 A and the hook of the rear-side second engaging portion  92 B are engaged with the through-holes of the guide rail  44 . A pin  124  is attached so as to extend over the second engaging portions  92 A,  92 B. Thus, the guide rail  44  is engaged with the frame  80 . 
     As shown in  FIG. 7B , the rotation shaft  60 A ( FIG. 2 ) of the conveyance roller  60  is received in the rotation-shaft support portion  88  of the frame  80 . 
     The stationary portion  111  of the supply arm  26  is screwed to the supply frame  100  by the screws  122  inserted in the through-holes  107  of the supply frame  100 , whereby the supply arm  26  is attached to the supply frame  100 . 
     As shown in  FIG. 4C , in a state in which the through-hole  86  formed in each contact plate portion  82  of the frame  80  and the through-hole  105  formed in each protruding portion  103  of the supply frame  100  are aligned with each other and the protrusion  106  of each protruding portion  103  is inserted from below into the through-hole  87  of each contact plate portion  82 , a screw is inserted into the through-hole  86 , the through-hole  105 , and a screw hole formed in the lower cover  12  so as to correspond to the through-hole  86  and the through-hole  105 , whereby the contact plate portions  82  of the frame  80  and the protruding portions  103  of the supply frame  100  are screwed to the lower cover  12 . 
     As shown in  FIG. 5 , a screw is inserted into each through-hole  90  of the frame  80  and each screw hole formed in the lower cover  12  so as to correspond to each through-hole  90 , whereby the frame  80  is screwed to the lower cover  12 . 
     Further, in a state in which the through-hole  108  of each projecting portion  104  of the supply frame  100  and a screw hole formed in the lower cover  12  so as to correspond to the through-hole  108  are positioned relative to each other, a screw is inserted into the through-hole  108  of each projecting portion  104  and the screw hole of the lower cover  12 , whereby the supply frame  100  is screwed to the lower cover  12 . 
     Transmission of Force from Supply Arm  26  to Supply Frame  100   
     As shown in  FIG. 2 , when the recording sheet  16  is supplied from the supply tray  20  by the supply roller  25 , a frictional force acts between: a lower surface of the uppermost sheet  16  and an upper surface of another sheet disposed right under the uppermost recording sheet  16  or a sheet support surface of the supply tray  20 . In this case, the uppermost recording sheet  16  tends to remain without being moved. This causes a resistance against rotation of the supply roller  25 , namely, against rotation of the supply roller  25  in a clockwise direction in  FIG. 2 , so that the supply roller  25  is moved forward. As a result, the pivotable portion  112  of the supply arm  26  pivots in a counterclockwise direction in  FIG. 2 , so that the pivot shaft  28  is moved upward by an upward force acting thereon. Consequently, the supply frame  100  receives the upward force from the stationary portion  111  that supports the pivot shaft  28 , as shown in  FIG. 7 . 
     As described above, the stationary portion  111  of the supply arm  26  is fixed by screwing to the vertical plate portion  102  of the supply frame  100 . The screwed positions of the supply frame  100  are in the region thereof located inward, in the right-left direction  9 , of the protruding portions  103  which are held in contact with the lower surfaces  82 A of the contact plate portions  82  of the frame  80 . Therefore, the upward force that is applied from the supply arm  26  to the supply frame  100  is a force that causes the central portion of the supply frame  100  in the right-left direction  9  to be moved upward. 
     Advantageous Effects 
     In the present embodiment, the supply frame  100  and the frame  80  are coupled to each other. As compared with an arrangement in which the frame  80  and the supply frame  100  are separately attached to the lower cover  12  formed of a resin member with a lower degree of dimensional accuracy, this arrangement ensures good positional accuracy between the supply frame  100  and the frame  80 , resulting in good positional accuracy between: the rotation shaft  25 A of the supply roller  25  supported by the supply frame  100 , namely, the pivot shaft  28  of the supply arm  26  supported by the supply frame  100 ; and the rotation shaft  60 A of the conveyance roller  60  supported by the frame  80 . Further, the upward force that acts on the supply frame  100  from the supply roller  25  via the supply arm  26  is received by the lower surfaces  82 A of the contact plate portions  82  of the frame  80 . The contact plate portions  82  are not easily deformed because of the wall portions  83 . It is consequently possible to prevent the frame  80  from being deformed by a force that acts thereon from the supply frame  100 . Thus, the recording sheet  16  is prevented from being skewed in the present embodiment. 
     In the present embodiment, the supply arm  26  is located at an intermediate position of the supply frame  100  in the right-left direction  9 , and the frame  80  includes the two contact plate portions  82  located at its opposite end portions in the right-left direction  9 . If the frame  80  does not include the wall portions  83 , the frame  80  tends to be deformed such that its central portion in the right-left direction  9  is displaced more easily than its opposite end portions in the right-left direction  9 . The present embodiment reduces a risk that the central portion of such a frame  80  in the right-left direction  9  receives the upward force that acts on the supply frame  100  from the supply roller  25 . Further, the frame  80  is prevented from being deformed due to displacement of the central portion of the supply frame  100  in the right-left direction  9 . 
     In the present embodiment, the supply frame  100  includes the vertical plate portion  102  which is bent downward with respect to the horizontal plate portion  101 . This arrangement prevents deformation of the supply frame  100  by the upward force that acts on the central portion of the supply frame  100  in the right-left direction  9  from the supply roller  25  via the supply arm  26 . 
     In the present embodiment, the MFP  10  includes the housing  14  including: the first conveyance path  65  configured to guide the recording sheet  16  such that the recording sheet  16  supplied from the supply roller  25  makes a U-turn, is then conveyed to the conveyance roller  60 , and is further conveyed downstream of the conveyance roller  60 ; and the switchback conveyance path  67  connected to the conveyance path  65  at two positions of the conveyance path  65 . Further, the frame  80  includes the two contact plate portions  82  which are spaced apart from each other in the right-left direction  9 . Moreover, the frame  80  and the supply frame  100  define the opening  121  between the two contact plate portions  82 , and the recording sheet  16  guided by the switchback conveyance path  67  passes through the opening  121 . According to the arrangement, the conveyance path  65  and the switchback conveyance path  67  effectuate switchback conveyance of the recording sheet  16 . Further, the switchback conveyance path  67  is partly defined, between the two contact plate portions  82  spaced apart from each other in the right-left direction  9 , by the front extending portion  84  of the frame  80  and the horizontal plate portion  101  of the supply frame  100 . Consequently, the switchback conveyance path  67  is formed without an increase in the size of the MFP  10 . 
     In the present embodiment, a portion of each contact plate portion  82  and the center of the pivot shaft  28  are located at the same position in the front-rear direction  8  perpendicular to the right-left direction  9 . In this arrangement, the contact plate portion  82  is located at a position at which the magnitude of a force transmitted from the supply frame  100  to the frame  80  is large, so that the frame  80  is effectively prevented from being deformed. 
     In the present embodiment, the supply roller  25  is constituted by the two rollers  34 ,  35  disposed so as to be spaced apart from each other in the right-left direction  9 . This arrangement is also effective for preventing the recording sheet  16  from being skewed. 
     In the MFP 10  according to the present embodiment, the recording head  39  is mounted on the carriage  23 , the carriage  23  is held by the guide rails  43 ,  44  such that the carriage  23  reciprocates along the right-left direction  9 , and the guide rails  43 ,  44  are supported by the frame  80 . This arrangement ensures positional accuracy between the recording head  39  and the conveyance roller  60 , in addition to positional accuracy between the supply roller  25  and the conveyance roller  60 . Consequently, an image can be accurately recorded on the recording sheet  16 . 
     According to the present embodiment, the recording sheets  16  can be accurately conveyed in the MFP  10  equipped with the supply roller  25  of a pendulum type. 
     Modifications 
     In the illustrated embodiment, the lower surface  82 A of each contact plate portion  82  extends along the plane defined by the front-rear direction  8  and the right-left direction  9 . The lower surface  82 A is not necessarily required to extend along the plane defined by the front-rear direction  8  and the right-left direction  9 . It is just required that the lower surface  82 A extends along a direction in which the lower surface  82 A can effectively receive the force transmitted from the supply frame  100  to the frame  80  via the supply arm  26 , the force being generated when the supply roller  25  supplies the recording sheet  16  from the supply tray  20 . 
     In the illustrated embodiment, the MFP  10  includes the switchback conveyance path  67  and is configured to perform image recording on both sides of the recording sheet  16 . The MFP  10  may be configured not to include the switchback conveyance path  67  and may perform image recording on only one side of the recording sheet  16 . 
     In the illustrated embodiment, the switchback conveyance path  67  is partially defined by the front extending portion  84  of the frame  80  and the horizontal plate portion  101  of the supply frame  100 . The switchback conveyance path  67  is not necessarily required to be defined by the frame  80  and the supply frame  100 . In the present embodiment, the switchback conveyance path  67  is configured such that the recording sheet  16  guided by the switchback conveyance path  67  passes through the opening  121  defined by the frame  80  and the supply frame  100 . The frame  80  and the supply frame  100  may be constructed so as not to contribute to formation of the switchback conveyance path  67 . In the construction, the recording sheet  16  guided by the switchback conveyance path  67  does not contact any of the frame  80  and the supply frame  100 . 
     In the illustrated embodiment, the supply roller  25  is constituted by the two rollers  34 ,  35  which are spaced apart from each other in the right-left direction  9 . The supply roller  25  may be constituted by a single roller. 
     In the illustrated embodiment, the switchback conveyance path  67  is disposed relative to the conveyance path  65  such that the branch position  36  is located downstream of the recording portion  24  in the conveyance path  65  and the merge position  37  is located upstream of the recording portion  24  in the conveyance path  65 . The switchback conveyance path  67  may be otherwise disposed. For instance, the switchback conveyance path  67  may be disposed such that both of the branch position  36  and the merge position  37  are located upstream of the recording portion  24  in the conveyance path  65 .