Patent Publication Number: US-2023134913-A1

Title: Recording apparatus

Description:
The present application is based on, and claims priority from JP Application Serial Number 2021-177188, filed Oct. 29, 2021, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a recording apparatus that performs recording on a medium. 
     2. Related Art 
     In a printer being an example of a recording apparatus, when there are irregularities on a placement surface of the apparatus, a shape of a main body frame is deformed. With this, accuracy of positions of respective units mounted to the main body frame is degraded. In view of this problem, JP-A-2000-068657 discloses a printer that has a frame structure assembled separately from the main body frame and includes an imaging unit and a writing unit mounted to the frame structure. According to the printer, the imaging unit and the writing unit are provided to the frame structure that is assembled separately from the main body frame, and hence degradation of accuracy of the positions of the respective units, which is caused by distortion of the main body frame, can be suppressed. 
     According to the printer described in JP-A-2000-068657, distortion of the main body frame is less likely to affect the frame structure including the imaging unit and the writing unit. However, there is room for improvement with regard to the following matters. 
     The printer described in JP-A-2000-068657 has a configuration in which the frame structure including the imaging unit and the writing unit is placed on two upper stays constituting the main body frame. More specifically, the frame structure including the imaging unit and the writing unit is supported at two points for each upper stay, and hence is the frame structure is supported at four points in total. Thus, when distortion of the main body frame is caused, a gap is formed between the frame structure and the upper stay at any one of the four supporting points. With this, there may be a risk of distortion of the frame structure. However, such a problem is not considered in the above-mentioned printer described in JP-A-2000-068657. 
     Further, when the frame structure is distorted, there may be a risk of relative positional deviation between a sheet transport path provided to the main body frame and a sheet transport path in the frame structure or posture fluctuation. In such a case, there may be a risk that a sheet cannot appropriately be transported. 
     Here, it has been understood that distortion of the main body frame has a specific tendency depending on the gravity center position of the apparatus. Specifically, for example, in a case in which the gravity center position of the apparatus is close to the back surface of the apparatus, when a protruding portion is on the placement surface of the apparatus, the front surface of the apparatus tends to have a floating position regardless of a position of the apparatus with respect to the protruding portion. There is no support from the placement surface at the position floating from the placement surface of the apparatus, and hence the main body frame is distorted. When the gravity center position of the apparatus is not at the center, and is deviated in a predetermined direction as described above, the frame on a side opposite thereto is likely to be distorted. Therefore, it is preferred that measures to prevent deformation of the main body frame be taken in view of the above-mentioned matter. 
     SUMMARY 
     In order to solve the above-mentioned problem, a recording apparatus according to the present disclosure includes a recording unit including a recorder configured to perform recording on a medium, and a first side plate and a second side plate being a pair of side plates positioned across the recording unit and being configured to support the recording unit, wherein an apparatus gravity center position is on a side close to the second side plate with respect to an intermediate position between the first side plate and the second side plate, the number of components of the recording unit that are supported by the first side plate is smaller than the number of components thereof that are supported by the second side plate, the recording unit includes a transport belt being a belt positioned at a position facing the recorder and being configured to transport the medium, the transport belt is stretched around a first pulley and a second pulley that are arranged along a transport direction of the medium, the components of the recording unit that are supported by the first side plate are positioned on an inner side of the transport belt when a transport path of the medium is viewed from a side, and the components of the recording unit that are supported by the second side plate are positioned on an inner side of an upstream extension region and an inner side of a downstream extension region when the transport path of the medium is viewed from a side, the upstream extension region being obtained by extending an inner region of the transport belt toward upstream of the transport path, the downstream extension region obtained by extending the inner region of the transport belt toward downstream of the transport path. 
     Further, a recording apparatus according to the present disclosure includes a recording unit including a recorder configured to perform recording on a medium, and a first side plate and a second side plate being a pair of side plates positioned across the recording unit and being configured to support the recording unit, wherein an apparatus gravity center position is on a side close to the second side plate with respect to an intermediate position between the first side plate and the second side plate, the number of components of the recording unit that are supported by the first side plate is smaller than the number of components thereof that are supported by the second side plate, the recording unit includes a supporting member being a member arranged at a position facing the recorder and being configured to support the medium, the components of the recording unit that are supported by the first side plate overlap with the supporting member when a transport path of the medium is viewed from a side, and the components of the recording unit that are supported by the second side plate are positioned on an inner side of an upstream extension region and an inner side of a downstream extension region when the transport path of the medium is viewed from a side, the upstream extension region being obtained by extending a region of the supporting member toward upstream of the transport path, the downstream extension region obtained by extending the region of the supporting member toward downstream of the transport path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view illustrating a medium transport path in a printer. 
         FIG.  2    is a view illustrating a positional relationship of a head unit, a cap carriage, and a wiper carriage. 
         FIG.  3    is a view schematically illustrating a relationship between a frame structure body and a motion unit. 
         FIG.  4    is a perspective view of the frame structure body on which the motion unit is mounted. 
         FIG.  5    is a perspective view of the frame structure body. 
         FIG.  6    is a perspective view of the frame structure body. 
         FIG.  7    is a perspective view of the motion unit. 
         FIG.  8    is a perspective view of the motion unit. 
         FIG.  9 A  and  FIG.  9 B  illustrate a guide at the time of insertion of the motion unit into the frame structure body. 
         FIG.  10 A ,  FIG.  10 B ,  FIG.  10 C , and  FIG.  10 D  are views schematically illustrating a relationship between a position of a protruding portion on a placement surface with respect to a leg portion and a floating position of the leg portion. 
         FIG.  11 A  and  FIG.  11 B  are views schematically illustrating deformation of a front frame. 
         FIG.  12    is a cross-sectional view of a part at which the motion unit and the front frame are coupled. 
         FIG.  13    is a view illustrating a positional relationship between a supported portion and a transport belt. 
         FIG.  14    is a view illustrating a medium transport path of a printer according to a second exemplary embodiment. 
         FIG.  15    is a view illustrating a positional relationship between a supported portion and a supporting member in the printer according to the second exemplary embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The present disclosure is described below in schematic matter. 
     A recording apparatus according to a first aspect includes a recording unit including a recorder configured to perform recording on a medium, and a first side plate and a second side plate being a pair of side plates positioned across the recording unit and being configured to support the recording unit, wherein an apparatus gravity center position is on a side close to the second side plate with respect to an intermediate position between the first side plate and the second side plate, the number of components of the recording unit that are supported by the first side plate is smaller than the number of components thereof that are supported by the second side plate, the recording unit includes a transport belt being a belt positioned at a position facing the recorder and being configured to transport the medium, the transport belt is stretched around a first pulley and a second pulley that are arranged along a transport direction of the medium, the components of the recording unit that are supported by the first side plate are positioned on an inner side of the transport belt when a transport path of the medium is viewed from a side, and the components of the recording unit that are supported by the second side plate are positioned on an inner side of an upstream extension region and an inner side of a downstream extension region when the transport path of the medium is viewed from a side, the upstream extension region being obtained by extending an inner region of the transport belt toward upstream of the transport path, the downstream extension region obtained by extending the inner region of the transport belt toward downstream of the transport path. 
     According to this aspect, the apparatus gravity center position is on the side close to the second side plate with respect to the intermediate position between the first side plate and the second side plate. With this, when a protruding portion is present on the placement surface of the apparatus, distortion of the first side plate is likely to occur. Further, the number of components of the recording unit that are supported by the first side plate is smaller than the number of components thereof that are supported by the second side plate. Thus, distortion of the first side plate is less likely to affect the recording unit. With this, even when the first side plate is distorted, distortion of the recording unit can be suppressed, and hence position deviation of the transport belt from the pair of side plates and posture fluctuation can be suppressed. With this, the medium can be transported as appropriate. 
     Further, when a component of the recording unit that is supported by the first side plate (hereinafter, referred to as a “first component”) is displaced downward due to distortion of the first side plate, a component of the recording unit that is supported by the second side plate (hereinafter, referred to as a “second component”) is also displaced downward. In this case, when the first component and the second component are away from each other in a horizontal direction, twist deformation is likely to occur in the recording unit. Thus, a posture of the transport belt is likely to fluctuate with respect to the pair of side plates. 
     In addition, the recording unit has a risk that position deviation of the recording unit from the pair of side plates or posture fluctuation is more significant as a location where distortion occurs in the recording unit is farther away from the first component and the second component. Specifically, as the transport belt is at a location farther away from the first component and the second component, position deviation of the transport belt from the pair of side plates or posture fluctuation is likely to be increased. 
     Further, when position deviation of the transport belt from the pair of side plates or posture fluctuation occurs, relative position deviation between a medium transport mechanism, which is provided to the pair of side plates, and the transport belt or posture fluctuation occurs. Thus, there may be a risk that appropriate transport cannot be performed. 
     In view of this point, in this aspect, the first component is arranged on the inner side of the transport belt when the transport path of the medium is viewed from a side, and the second component is arranged on the inner side of the upstream extension region and the inner side of the downstream extension region when the transport path of the medium is viewed from a side, the upstream extension region being obtained by extending, toward upstream of the transport path, the inner region of the transport belt, the downstream extension region being obtained by extending, toward downstream of the transport path, the inner region of the transport belt. 
     With this, the second component is arranged across the first component. Thus, when the first component is displaced downward due to distortion of the first side plate, twist of the recording unit can be suppressed. 
     Further, the first component and the second component are arranged at positions close to the transport belt. Thus, position deviation of the transport belt from the pair of side plates or posture fluctuation at the time of occurrence of distortion in the recording unit can be suppressed. 
     With this, even when the first side plate is distorted, the medium can be transported as appropriate. 
     In addition, the recorder is positioned at a position facing the transport belt. Thus, position deviation of the recorder from the pair of side plates or posture fluctuation can also be suppressed. 
     A recording apparatus according to a second aspect includes a recording unit including a recorder configured to perform recording on a medium, and a first side plate and a second side plate being a pair of side plates positioned across the recording unit and being configured to support the recording unit, wherein an apparatus gravity center position is on a side close to the second side plate with respect to an intermediate position between the first side plate and the second side plate, the number of components of the recording unit that are supported by the first side plate is smaller than the number of components thereof that are supported by the second side plate, the recording unit includes a supporting member being a member arranged at a position facing the recorder and being configured to support the medium, the components of the recording unit that are supported by the first side plate overlap with the supporting member when a transport path of the medium is viewed from a side, and the components of the recording unit that are supported by the second side plate are positioned on an inner side of an upstream extension region and an inner side of a downstream extension region when the transport path of the medium is viewed from a side, the upstream extension region being obtained by extending a region of the supporting member toward upstream of the transport path, the downstream extension region obtained by extending the region of the supporting member toward downstream of the transport path. 
     In this aspect, similarly to the first aspect, the first component is positioned on the inner side of the supporting member when the transport path of the medium is viewed from a side, and the second component is positioned on the inner side of the upstream extension region and the inner side of the downstream extension region when the transport path of the medium is viewed from a side, the upstream extension region being obtained by extending, toward upstream of the transport path, the region of the supporting member, the downstream extension region being obtained by extending, toward downstream of the transport path, the inner region of the supporting member. 
     With this, the second component is arranged across the first component. Thus, when the first component is displaced downward due to distortion of the first side plate, twist of the recording unit can be suppressed. 
     Further, the first component and the second component are arranged at positions close to the supporting member. Thus, position deviation of the supporting member from the pair of side plates or posture fluctuation at the time of occurrence of distortion in the recording unit can be suppressed. 
     With this, even when the first side plate is distorted, the medium can be transported as appropriate. 
     In addition, the recorder is positioned at a position facing the supporting member. Thus, position deviation of the recorder from the pair of side plates or posture fluctuation can also be suppressed. 
     According to the first aspect or the second aspect, in a third aspect, the recording unit is supported at one position being a first supported portion at the first side plate, and is supported at two positions being a second supported portion and a third supported portion at the second side plate. When the transport path of the medium is viewed from a side, the second supported portion is positioned the inner side of the upstream extension region, and the third supported portion is positioned on the inner side of the downstream extension region. 
     According to this aspect, the recording unit is supported at one position being the first supported portion at the first side plate, and is supported at two positions being the second supported portion and the third supported portion at the second side plate. Thus, while the second side plate securely supports the recording unit, the distortion of first side plate can be prevented from affecting the recording unit more securely. 
     According to the first aspect, in a fourth aspect, when the transport path of the medium is viewed from a side, the second supported portion is positioned the inner side of the upstream extension region, and the third supported portion is positioned on the inner side of the downstream extension region. When the transport path of the medium is viewed from a side, the first supported portion is positioned on a linear line coupling a rotation center of the first pulley and a rotation center of the second pulley to each other. When the transport path of the medium is viewed from a side, the second supported portion is positioned on a linear line obtained by extending, toward upstream of the transport path, the linear line coupling the rotation center of the first pulley and the rotation center of the second pulley to each other. When the transport path of the medium is viewed from a side, the third supported portion is positioned on a linear line obtained by extending, toward downstream of the transport path, the linear line coupling the rotation center of the first pulley and the rotation center of the second pulley to each other. 
     According to this aspect, each of the first supported portion, the second supported portion, and the third supported portion is on the linear line coupling the rotation center of the first pulley and the rotation center of the second pulley to each other or on the extension line of the linear line, when the transport path of the medium is viewed from a side. In this configuration, the actions and effects of the above-mentioned first aspect can be obtained. 
     According to the third aspect or the fourth aspect, in a fifth aspect, the first supported portion is within a region of the recorder in the transport direction of the medium. 
     According to this aspect, the first supported portion is within the region of the recorder in the transport direction of the medium. Thus, posture fluctuation of the recorder with respect to the pair of side plates at the time of distortion of the first side plate can be suppressed. 
     According to any one of the third aspect to the fifth aspect, in a sixth aspect, the recording unit includes a first sub frame being a frame facing the first side plate and including the first supported portion, and a second sub frame being a frame facing the second side plate and including the second supported portion and the third supported portion. 
     According to this aspect, the recording unit includes the first sub frame being a frame facing the first side plate and including the first supported portion, and the second sub frame being a frame facing the second side plate and including the second supported portion and the third supported portion. In this configuration, the actions and effects of any one of the second aspect to the fourth aspects described above can be obtained. 
     According to the sixth aspect, in a seventh aspect, the first supported portion is formed as a first supported protrusion that is fitted in a first supporting hole formed in the first side plate, the second supported portion is formed as a second supported protrusion that is fitted in a second supporting hole formed in the second side plate, the third supported portion is formed as a third supported protrusion that is fitted in a third supporting hole formed in the second side plate, and a larger gap is secured for fitting between the third supported protrusion and the third supporting hole, as compared to fitting between the second supported protrusion and the second supporting hole. 
     According to this aspect, a larger gap is secured for fitting between the third supported protrusion and the third supporting hole, as compared to fitting between the second supported protrusion and the second supporting hole. Thus, variation of the distance between the second supported protrusion and the third supported protrusion can be canceled by the gap. With this, the recording unit can be mounted to the pair of side plates as appropriate. 
     According to the seventh aspect, in an eighth aspect, the second side plate has a through hole through which the recording unit passes, and when the recording unit moves toward the first side plate through the through hole, the first supported protrusion enters the first supporting hole, the second supported protrusion enters the second supporting hole, and the third supported protrusion enters the third supporting hole. 
     According to this aspect, workability for mounting the recording unit to the pair of side plates is facilitated. 
     According to the eighth aspect, in a ninth aspect, the first side plate and the second side plate are coupled to each other via a coupling member, and when the recording unit moves toward the first side plate through the through hole, the coupling member supports the recording unit and guides the recording unit toward the first side plate. 
     According to this aspect, when the recording unit moves toward the first side plate through the through hole, the coupling member supports the recording unit, and guides the recording unit toward the first side plate. Thus, workability for mounting the recording unit to the pair of side plates is more facilitated. 
     According to the ninth aspect, in a tenth aspect, the recorder includes a liquid ejection head configured to eject a liquid onto the medium, and a liquid storage between the first side plate and the second side plate, the liquid storage being configured to accommodate the liquid ejected from the liquid ejection head. The coupling member separates an arrangement region the liquid storage and an arrangement region of the recorder from each other between the first side plate and the second side plate. 
     According to this aspect, in addition to a function of coupling the first side plate and the second side plate to each other and a function of supporting the recording unit and guiding the recording unit toward the first side plate, the coupling member also has a function of separating the arrangement region of the liquid storage and the arrangement region of the recorder from each other between the first side plate and the second side plate. Thus, the number of components can be reduced, and hence increase in size and cost of the apparatus can be suppressed. 
     According to any one of the first aspect to the tenth aspect, in an eleventh aspect, the recording unit is coupled to the first side plate with play, the play is play in a direction in which the first side plate is at least away from the second side plate, the recording unit is coupled to the first side plate by a stepped screw, the stepped screw has a head portion, a screw portion that is fitted in a screw hole in the recording unit, and a cylinder portion having a diameter larger than the screw portion and being provided between the head portion and the screw portion, and the cylinder portion is inserted into a through hole formed in the first side plate. 
     According to this aspect, the recording unit is coupled to the first side plate with play. Thus, while defining the position of the recording unit with respect to the pair of side plates, distortion of the first side plate can be prevented from affecting the recording unit. 
     Further, the play is play in the direction in which the first side plate is at least away from the second side plate. Thus, distortion of the first side plate in the direction in which the first side plate is away from the second side plate is less likely to affect the recording unit. 
     Further, the stepped screw is used. With this, the play can be secured, and the first side plate and the recording unit can easily be coupled to each other. 
     According to any one of the first aspect to the eleventh aspect, in a twelfth aspect, a leg portion is provided at each of four corners of a bottom portion of an apparatus main body. 
     According to this aspect, in the configuration in which the leg portion is provided at each of the four corners of the bottom portion of the apparatus body, the actions and effects in any one of the first aspect to the twelfth aspect can be obtained. 
     The present disclosure is described below in detail. 
     An ink-jet printer  1  performs recording by ejecting a liquid, which is representatively exemplified by ink, onto a medium, which is representatively exemplified by recording paper. Such a printer is described below as an example of a recording apparatus. In the following description, the ink-jet printer  1  is referred to as a printer  1  in an abbreviated manner. The printer  1  corresponds to a recording apparatus according to a first exemplary embodiment. 
     An X-Y-Z coordinate system illustrated in each of the drawings is an orthogonal coordinate system. A Y-axis direction corresponds to a width direction intersecting the transport direction of the medium, and also corresponds to the apparatus depth direction. A +Y direction being a direction in which the arrow is oriented in the Y-axis direction corresponds to a direction from an apparatus front surface to an apparatus back surface, and a −Y direction opposite to the +Y direction corresponds to a direction from the apparatus back surface to the apparatus front surface. 
     Further, an X-axis direction corresponds to the width direction of the apparatus. A +X direction being a direction in which the arrow is oriented as viewed from an operator of the printer  1  corresponds to a left side, and a −X direction opposite thereto corresponds to a right side. The Z-axis direction corresponds to a vertical direction, that is, the height direction of the apparatus. A +Z direction being a direction in which the arrow is oriented corresponds to an upper direction, and a −Z direction opposite thereto corresponds to a lower direction. In the following description, the term “up” in indicates the +Z direction, and the term “down” indicates the −Z direction. 
     Further, a G-axis direction corresponds to a normal line direction of a line head  34 , which is described later, with respect to an ink ejection surface  35 . A +G direction being a direction in which the arrow is oriented corresponds to a direction in which a head unit  33  is away from a transport belt  7 , and a −G direction opposite thereto is a direction in which the head unit  33  approaches the transport belt  7 . 
     Further, an F-axis direction corresponds to a direction parallel to the ink ejection surface  35 . A +F direction being the medium transport direction at a position facing the ink ejection surface  35  and a direction in which the arrow is oriented corresponds to downstream in the transport direction, and a −F direction opposite thereto corresponds to upstream in the transport direction. Note that, in the following description, a side to which the medium is fed is referred to as “downstream”, and a side opposite thereto is referred to as “upstream” in some cases. Further, the F-axis direction is a moving direction of a cap carriage  31  described later. 
     Further, in some of the drawings, an F-G-Y coordinate system is used in place of the X-Y-Z coordinate system. 
     In  FIG.  1   , a medium transport path is indicated with the broken line. In the printer  1 , the medium is transported in the medium transport path indicated with the broken line. 
     An apparatus main body  2  of the printer  1  includes a medium cassette  3  that accommodates the medium before feeding. The reference symbol P indicates the medium accommodated in each medium cassette. The medium cassette  3  is provided to the apparatus main body  2  so as to be removed from the apparatus front side. 
     The medium cassette  3  is provided with a pick roller  9  that feeds out the accommodated medium. The medium fed out by the pick roller  9  is fed obliquely upward by a feeding roller pair  10 . 
     Note that, in the following description, the term “roller pair” includes a driving roller driven by a motor, which is not illustrated, and a driven roller to rotate in contact with the driving roller, unless otherwise noted. 
     The medium is fed from the feeding roller pair  10  to a transport roller pair  16 . The medium that receives a feeding force from the transport roller pair  16  is fed to a position between the line head  34  and the transport belt  7 , that is, a position facing the line head  34 . 
     The line head  34  performs recording by ejecting an ink onto a surface of the medium. The line head  34  is an ink ejection head configured so that nozzles (not illustrated) for ejecting an ink cover the entire medium in the width direction, and is configured as an ink ejection head capable of performing recording on the entire medium in the width direction without moving in the medium width direction. The line head  34  is an example of a liquid ejection head that ejects a liquid. 
     The reference symbols  13 A,  13 B,  13 C, and  13 D indicate ink storages as liquid storages. The ink ejected from the line head  34  is supplied from each of the ink storages to the line head  34  via tube omitted in illustration. The ink storages  13 A,  13 B,  13 C, and  13 D are provided to mounters  14 A,  14 B,  14 C, and  14 D, respectively, so as to be removed from the apparatus front surface side. 
     Further, the reference symbol  15  indicates a waste liquid storage that stores the ink as a waste liquid. The waste liquid is ejected from the line head  34  to a cap  32  (see  FIG.  2   ), which is described later, for the purpose of maintenance work. 
     Note that the reference symbol  46  indicates a second partition frame that separates the arrangement region of the head unit  33  and the arrangement region of the ink storages  13 A,  13 B,  13 C, and  13 D from each other. The second partition frame is described later. 
     The transport belt  7 , a first pulley  8   a , and a second pulley  8   b  constitute a transport unit  6 . The transport belt  7  is an endless belt that is stretched around the first pulley  8   a  and the second pulley  8   b  that are arranged along the medium transport direction. The transport belt  7  rotates when at least one of the first pulley  8   a  and the second pulley  8   b  is driven by a motor, which is not illustrated. 
     The medium is transported is sucked on a belt surface of the transport belt  7 , and is transported along the position facing the line head  34 . For suction of the medium on the transport belt  7 , a publicly-known suction method such as an air suction method and an electrostatic suction method may be adopted. 
     Here, the medium transport path passing through the position facing the line head  34  intersects both the horizontal direction and the vertical direction, and has a configuration in which the medium is transported obliquely upward. The obliquely upward transport direction is a direction including a −X direction component and a +Z direction component in  FIG.  1   . With this configuration, the dimension of the printer  1  in the horizontal direction can be suppressed. 
     Note that, in the present exemplary embodiment, the medium transport path passing through the position facing the line head  34  is set to have an inclination angle falling within the range from 70 degrees to 80 degrees with respect to the horizontal direction, and is set to have an inclination angle of 75 degrees, as an example. 
     The medium having a first surface subjected to recording by the line head  34  is further fed obliquely upward by a transport roller pair  17  positioned downstream of the transport belt  7 . 
     A flap  24  is provided downstream of the transport roller pair  17 , and the flap  24  switches the transport direction of the medium. When the medium is directly discharged, the flap  24  switches the transport path of the medium toward a transport roller pair  21  provided above. When the medium is fed toward the transport roller pair  21 , the medium is discharged onto a discharge tray  4 . The discharge tray  4  is a tray that is inclined obliquely upward in a direction including a +X direction component and a +Z direction component. 
     When recording is further performed on a second surface in addition to the first surface of the medium, the medium is fed by the flap  24  obliquely upward in a direction including a −X direction component and a +Z direction component, passes through a branching position K 1 , and is fed from the branching position K 1  to a switch-back path above. The switch-back path is provided with transport roller pairs  22  and  23 . The medium that reaches the switch-back path is transported upward by the transport roller pairs  22  and  23 . Further, when the trailing edge of the medium passes through the branching position K 1 , rotation of the transport roller pairs  22  and  23  is switched. With this, the medium is transported downward. 
     The medium that is transported downward by the transport roller pairs  22  and  23  receives a feeding force from a transport roller pair  18 , a transport roller pair  19 , and a transport roller pair  20 , arrives at the transport roller pair  16 , and then is fed again to the position facing the line head  34  by the transport roller pair  16 . When the medium that is fed again to the position facing the line head  34 , the second surface opposite to the first surface on which recording is already performed faces the line head  34 . With this, the line head  34  is capable of performing recording on the second surface of the medium. The medium having the second surface on which recording is performed is discharged by the transport roller pair  21 . 
     Next, a motion unit  25  is described. The motion unit  25  (see  FIG.  7   ) is an example of the recording unit. The motion unit  25  includes the head unit  33 , the cap carriage  31 , and a wiper carriage  36  that are illustrated in  FIG.  2   . Note that, in  FIG.  7   , the cap carriage  31  and the wiper carriage  36  are omitted in illustration. Further, in  FIG.  8   , the head unit  33 , the cap carriage  31 , and the wiper carriage  36  are omitted in illustration. 
     In  FIG.  2   , the head unit  33  is a unit including the line head  34 , and is provided so as to be driven by a motor, which is not illustrated, along the G-axis direction. The head unit  33  is an example of a recorder. 
     In  FIG.  2   , the cap carriage  31  is an example of a cap unit including the cap  32  for covering the line head  34 , and is provided so as to be driven by a motor, which is not illustrated, along the F-axis direction. 
     The wiper carriage  36  is a unit provided with a wiper  37  for performing wiping on the ink ejection surface  35  of the line head  34 , and is provided so as to be driven by a motor, which is not illustrated, along the Y-axis direction. 
     In this manner, the head unit  33 , the cap carriage  31 , and the wiper carriage  36  are provided in the motion unit  25  in directions orthogonal to one another so as to be driven. 
       FIG.  2    illustrates positions of the respective units when the line head  34  performs recording on the medium. A position G 1  is a position of the ink ejection surface  35  in the G-axis direction in this state. In this state, the cap carriage  31  is at a retracting position in the −F direction with respect to the head unit  33 , and the wiper carriage  36  is at a home position set in the +Y direction. 
     When the ink ejection surface  35  is capped with the cap  32  included in the cap carriage  31  from this state, the head unit  33  retracts in the +G direction from the position in  FIG.  2   , and the cap carriage  31  moves in the +F direction. With this, the ink ejection surface  35  and the cap  32  face each other. When the ink ejection surface  35  and the cap  32  face each other, the head unit  33  moves in the −G direction. With this, the ink ejection surface  35  is capped with the cap  32 . A position G 2  is a position of the ink ejection surface  35  in the G-axis direction when the ink ejection surface  35  is capped with the cap  32 . 
     When the wiper  37  included in the wiper carriage  36  performs wiping on the ink ejection surface  35 , the head unit  33  retracts in the +G direction from the state in  FIG.  2   . Further, the wiper carriage  36  moves from the home position in the +Y direction to an end position in the −Y direction. After that, the head unit  33  slightly moves in the −G direction, and the wiper carriage  36  moves in the +Y direction while the ink ejection surface  35  is at a position G 3 . With this, the wiper  37  performs wiping on the ink ejection surface  35 . 
     Subsequently, as illustrated in  FIG.  3   ,  FIG.  7   , and  FIG.  8   , the motion unit  25  includes a first sub frame  26  and a second sub frame  27  that is positioned in the +Y direction with respect to the first sub frame  26 . Each of the first sub frame  26  and the second sub frame  27  is formed of a metal plate material, and forms a frame surface along an F-G plane. 
     As illustrated in  FIG.  7    and  FIG.  8   , the first sub frame  26  and the second sub frame  27  are coupled to each other with a first coupling frame  28 , a second coupling frame  29 , and a third coupling frame  30  that extend in the Y-axis direction. Each of the first coupling frame  28 , the second coupling frame  29 , and the third coupling frame  30  is formed by subjecting a metal plate material to bending processing. 
     In the present exemplary embodiment, the first coupling frame  28 , the second coupling frame  29 , and the third coupling frame  30  are joined to the first sub frame  26  and the second sub frame  27  by welding. With this, rigidity of the entire motion unit  25  is secured. 
     Each of the first coupling frame  28 , the second coupling frame  29 , and the third coupling frame  30  is obtained by bending processing so that a part or an entirety of a cross-section thereof, which is taken along the F-G plane, is square (see  FIG.  2   ). With this, rigidity of the motion unit  25  is further improved. 
     As illustrated in  FIG.  3   , the apparatus main body  2  includes a front frame  40  at the end in the −Y direction, and includes a rear frame  41  at the end in the +Y direction. The front frame  40  and the rear frame  41  are collectively an example of a pair of side plates positioned across the motion unit  25 . The front frame  40  is an example of the first side plate, and the rear frame  41  is an example of the second side plate. 
     The front frame  40  stands upright on a first bottom frame  42 , and the rear frame  41  stands upright on a second bottom frame  43 . Each of the front frame  40 , the rear frame  41 , the first bottom frame  42 , and the second bottom frame  43  is formed of a metal material. 
     The motion unit  25  is supported by the front frame  40  and the rear frame  41 . Further, the front frame  40 , the rear frame  41 , the first bottom frame  42 , the second bottom frame  43 , and the motion unit  25  constitute a frame structure body  39  being a base body of the apparatus main body  2 . 
     Note that  FIG.  3    is a schematic view. In actuality, as illustrated in  FIG.  4    and  FIG.  5   , the frame structure body  39  includes a plurality of stays and frames formed of metal materials in addition to the front frame  40 , the rear frame  41 , the first bottom frame  42 , the second bottom frame  43 , and the motion unit  25 . This matter is described later. 
     Further, the exterior of the frame structure body  39  is a casing body formed of a resin material. However, description therefor is also omitted. The frame structure body  39  formed of a metal material and the casing body formed of a resin material constitute the apparatus main body  2 . 
     As illustrated in  FIG.  3   , the front frame  40  forms a frame surface parallel to an X-Z plane so as to extend along a front surface  2   a  of the apparatus main body  2 . Further, the rear frame  41  forms a frame surface parallel to the X-Z plane so as to extend along a back surface  2   b  of the apparatus main body  2 . The first bottom frame  42  and the second bottom frame  43  form a frame surface parallel to an X-Y plane so as to extend along a bottom surface  2   c  of the apparatus main body  2 . 
     The first bottom frame  42  is provided with a front right leg portion  51  and a front left leg portion  52 , and the second bottom frame  43  is provided with a rear right leg portion  53  and a rear left leg portion  54 . In other words, the leg portions are provided at the four corners of the apparatus main body  2 , respectively. The apparatus main body  2  is placed on a placement surface G via the four leg portions including the front right leg portion  51 , the front left leg portion  52 , the rear right leg portion  53 , and the rear left leg portion  54 . Note that, in the following description, when there is no particular need to distinguish the front right leg portion  51 , the front left leg portion  52 , the rear right leg portion  53 , and the rear left leg portion  54  from one another, those portions are simply referred to as a “leg portion” in some cases. 
     Subsequently, the configuration of the frame structure body  39  is further described in detail. 
     As illustrated in  FIG.  4    and  FIG.  5   , the front frame  40  has a first opening portion  40   a  for exposing the first sub frame  26  of the motion unit  25 . A second opening portion  40   k  is formed in the first opening portion  40   a  in the +X direction. Further, a third opening portion  40   m  is formed below the second opening portion  40   k.    
     The second opening portion  40   k  is an opening portion for accessing the ink storages  13 A,  13 B,  13 C, and  13 D, the mounters  14 A,  14 B,  14 C, and  14 D, and the waste liquid storage  15 , which are described with reference to  FIG.  1   , from the apparatus front side. 
     Further, the third opening portion  40   m  is an opening portion for mounting and removing the medium cassette  3 , which is described with reference to  FIG.  1   , from the apparatus front side. 
     The front frame  40  is obtained by welding a plurality of members. Specifically, the front frame  40  is obtained by including the first frame portion  40   f  having the first opening portion  40   a  formed therein, as a base, and welding a second frame portion  40   g , a third frame portion  40   h , a fourth frame portion  40   j , and the first bottom frame  42  to one another. 
     The second frame portion  40   g  extends along the Z-axis direction, and forms a left edge of the second opening portion  40   k . The third frame portion  40   h  extends along the X-axis direction, and forms a lower edge of the second opening portion  40   k  and forms an upper edge of the third opening portion  40   m . The first bottom frame  42  extends along the X-axis direction, and forms a lower edge of the third opening portion  40   m.    
     In this manner, the front frame  40  is obtained by coupling the plurality of frames to one another. With this, while the second opening portion  40   k  and the third opening portion  40   m  are formed, the front frame  40  with secured rigidity can be obtained at low cost. 
     In  FIG.  4    and  FIG.  5   , an opening portion  41   a  being a through hole through which the motion unit  25  passes is formed in the rear frame  41 . When the motion unit  25  is arranged between the front frame  40  and the rear frame  41 , the motion unit  25  moves from the +Y direction to the −Y direction with respect to the rear frame  41 , as indicated with the arrow A in  FIG.  5   . With this, a first supported protrusion  55  provided to the motion unit  25  enters a first supporting hole  40   b  provided in the front frame  40 , a second supported protrusion  56  provided to the motion unit  25  enters a second supporting hole  41   c  provided in the rear frame  41 , and a third supported protrusion  57  provided to the motion unit  25  enters a third supporting hole  41   d  provided in the rear frame  41 . Specifically, the motion unit  25  is supported by the front frame  40  and the rear frame  41 . 
     Note that, in the following description, when there is no particular need to distinguish the first supported protrusion  55 , the second supported protrusion  56 , and the third supported protrusion  57  from one another, those protrusions are simply referred to as a supported protrusion in some cases. Similarly, in the following description, when there is no particular need to distinguish the first supporting hole  40   b , the second supporting hole  41   c , and the third supporting hole  41   d  from one another, those supporting holes are simply referred to as a supporting hole in some cases. 
     In this manner, the motion unit  25  moves toward the front frame  40  through the opening portion  41   a . With this, the respective supported protrusions enter the respective supporting holes, and the motion unit  25  is supported by the front frame  40  and the rear frame  41 . Thus, workability for mounting the motion unit  25  to the front frame  40  and the rear frame  41  is facilitated. 
     Note that the respective supported protrusions and the respective supporting holes are described later again in detail. 
     The front frame  40  and the rear frame  41  are coupled to each other with a plurality of stays. Specifically, the front frame  40  and the rear frame  41  are coupled to each other with the first stay  44   a , a second stay  44   b , a third stay  44   c , a fourth stay  44   d , a fifth stay  44   e , and a sixth stay  44   f . Each of the stays is a stay extending along the Y-axis direction, is formed of a metal material, and is fixed to the front frame  40  and the rear frame  41  by welding or screwing. 
     Note that the first stay  44   a  has a bent portion M obtained by bending a side, which is close to the bottom surface  2   c  of the apparatus main body  2 , to the inner side of the apparatus main body  2  so as to have an L-like shape. Rollers (not illustrated) of the medium cassette  3  are placed on the bend portion M, thereby exerting a function as a cassette rail. With this structure, there is no need to prepare additional cassette rail components. Thus, the number of components can be reduced, and hence increase in size and cost of the apparatus can be suppressed. 
     Further, a first partition frame  45  and the second partition frame  46  are provided between the front frame  40  and the rear frame  41 . In other words, the front frame  40  and the rear frame  41  are coupled to each other by the first partition frame  45  and the second partition frame  46  in addition to the respective stays described above. 
     The first partition frame  45  forms a surface parallel to the X-Y plane, and forms an accommodation space for accommodating the medium cassette  3  (see  FIG.  1   ). 
     The second partition frame  46  has an L-like shape as viewed in the +Y direction so as to have a first part  46   a  forming a surface parallel to a Y-Z plane and a second part  46   b  forming a surface parallel to the X-Y plane. The second partition frame  46  has a function of separating the arrangement region of the head unit  33  and the arrangement region of the ink storages  13 A,  13 B,  13 C, and  13 D from each other between the front frame  40  and the rear frame  41 . 
     Here, when the motion unit  25  moves toward the front frame  40  through the opening portion  41   a , the second partition frame  46  supports the motion unit  25  with the second part  46   b , and guides the motion unit  25  toward the front frame  40 . Note that the component of the motion unit  25  that is supported by the second partition frame  46  is the first coupling frame  28  (see  FIG.  8   ). 
     With this, workability for mounting the motion unit  25  to the front frame  40  and the rear frame  41  is further facilitated. 
     Further, the second partition frame  46  also has a function of separating the arrangement region of the head unit  33  and the arrangement region of the ink storages  13 A,  13 B,  13 C, and  13 D from each other, in addition to a function of supporting and guiding the motion unit  25  toward the front frame  40 . Thus, the number of components can be reduced, and hence increase in size and cost of the apparatus can be suppressed. 
     Note that, as illustrated in  FIG.  9 A  and  FIG.  9 B , a bent upright portion  41   e  is formed at the opening portion  41   a  of the rear frame  41 . The bent upright portion  41   e  is formed in the vicinity of the third supporting hole  41   d , and is formed so as to be bent in the −Y direction. When the motion unit  25  moves toward the front frame  40  through the opening portion  41   a , the bent upright portion  41   e  supports the motion unit  25  together with the second partition frame  46  described above. Note that, as illustrated in  FIG.  9 B , the component of the motion unit  25  that is supported by the bent upright portion  41   e  is the second coupling frame  29 . 
     Note that the distance between the third supporting hole  41   d  and the bent upright portion  41   e  is set so that the second coupling frame  29  is away from the bent upright portion  41   e  when the respective supported protrusions are supported by the respective supporting holes. Similarly, the position of the second part  46   b  is set so that the first coupling frame  28  is away from the second part  46   b  of the second partition frame  46  when the respective supported protrusions are supported by the respective supporting holes. With this, under a state in which the respective supported protrusions are supported by the respective supporting holes, the bent upright portion  41   e  and the second partition frame  46  can be prevented from disadvantageously affecting positioning accuracy of the respective supported protrusions by the respective supporting holes. 
     Next, a gravity center position of the apparatus main body  2  is described. Further, along with this, description is made on distortion of the frame when any one of the four leg portions stands on a protruding portion (not illustrated) on the placement surface G. 
       FIG.  10    is a plan view of the bottom surface  2   c  as the apparatus main body  2  is viewed from below. In  FIG.  10   , a linear line CLx is a linear line parallel to the Y axis, and is a linear line passing through the center position of the apparatus main body  2  in the X-axis direction. Further, a linear line CLy is a linear line parallel to the X axis, and is a linear line passing through the center position of the apparatus main body  2  in the Y-axis direction. Note that the center position of the apparatus main body  2  in the Y-axis direction is also an intermediate position of the front frame  40  and the rear frame  41  in the Y-axis direction. 
     The reference symbol M indicates a gravity center position of the apparatus main body  2 . As illustrated, the gravity center position M of the apparatus main body  2  is on the rear side (in the +Y direction with respect to the linear line CLy) in the apparatus front-rear direction (in the Y-axis direction), in other words, on a side close to the rear frame  41 . Further, the gravity center position M is on the right side (in the −X direction with respect to the linear line CLx) in the apparatus right-left direction (in the X-axis direction). 
     With this configuration as described above, in a case in which the protruding portion caused by a bump, a foreign matter, or the like is on the placement surface G (see  FIG.  1    and  FIG.  3   ), when any one of the four leg portions stands on the protruding portion, the frame structure body  39  is distorted. 
     Details are further described below. The leg portion indicated with the outlined arrow in  FIG.  10    is a leg portion that stands on the protruding portion of the placement surface G. The painted leg portion is a leg portion in contact with the placement surface G. The outlined leg portion is a leg portion that floats from the placement surface G. 
     For example,  FIG.  10 A  illustrates a case in which the front left leg portion  52  stands of the protruding portion of the placement surface G. In this case, the gravity center of the apparatus main body  2  is on the rear side, and hence the apparatus main body  2  in inclined to the rear side (in the +Y direction). As a result, the front left leg portion  52 , the rear right leg portion  53 , and the rear left leg portion  54  are held in contact with the placement surface G, and the front right leg portion  51  floats from the placement surface G. 
     Further,  FIG.  10 B  illustrates a case in which the front right leg portion  51  stands of the protruding portion of the placement surface G. In this case, the gravity center of the apparatus main body  2  is on the rear side, and hence the apparatus main body  2  in inclined to the rear side (in the +Y direction). As a result, the front right leg portion  51 , the rear right leg portion  53 , and the rear left leg portion  54  are held in contact with the placement surface G, and the front left leg portion  52  floats from the placement surface G. 
     Further,  FIG.  10 C  illustrates a case in which the rear right leg portion  53  stands on the protruding portion of the placement surface G. In this case, the apparatus main body  2  is inclined to the left side (in the +X direction). As a result, the front left leg portion  52 , the rear right leg portion  53 , and the rear left leg portion  54  are held in contact with the placement surface G, and the front right leg portion  51  floats from the placement surface G. 
     Further,  FIG.  10 D  illustrates a case in which the rear left leg portion  54  stands on the protruding portion of the placement surface G. In this case, the apparatus main body  2  is inclined to the right side (in the −X direction). As a result, the front right leg portion  51 , the rear right leg portion  53 , and the rear left leg portion  54  are held in contact with the placement surface G, and the front left leg portion  52  floats from the placement surface G. 
     Specifically, even when any one of the four leg portions stands on the protruding portion of the placement surface G, the apparatus front side floats. Thus, any one of the front right leg portion  51  and the front left leg portion  52  floats. The part floating from the placement surface G is not supported by the placement surface G, and hence the frame is distorted. Specifically, even when any one of the four leg portions stands on the protruding portion of the placement surface G, the front frame  40  is distorted. 
       FIG.  11    schematically illustrates distortion occurring to the front frame  40  when the front right leg portion  51  floats, and the broken line and the reference symbol  40 - 1  indicate the front frame  40  that is distorted. When the front right leg portion  51  floats, the front frame  40  is deformed downward as indicated with the arrow in the apparatus front view, as illustrated in  FIG.  11 A . Further, as illustrated in  FIG.  11 B , there may be a case in which the front frame  40  is deformed so as to fall frontward as indicated with the arrow in the apparatus side view. 
     Note that the present exemplary embodiment includes the four leg portions, but is not limited thereto. Five or more leg portions may be provided. Further, in a case in which the apparatus bottom surface is not provided with the leg portion, when the gravity center of the apparatus main body  2  is on the rear side, the apparatus front side floats similarly to the above-mentioned case. Thus, the front frame  40  is distorted. 
     In view of the above-mentioned problem, in the printer  1 , first, the number of components of the motion unit  25  that are supported by the front frame  40  is smaller than the number of components thereof that are supported by the rear frame  41 . 
     Specifically, as illustrated in  FIG.  4   , the motion unit  25  includes the three supported protrusions including the first supported protrusion  55 , the second supported protrusion  56 , and the third supported protrusion  57 . Those supported protrusions are supported by the front frame  40  and the rear frame  41 . 
     Among those three supported protrusions, the first supported protrusion  55  is provided to the first sub frame  26  that faces the front frame  40 , and the second supported protrusion  56  and the third supported protrusion  57  are provided to the second sub frame  27  that faces the rear frame  41 . Each of the protrusions has a perfect circle shape as viewed in the Y-axis direction. Further, each of the protrusions protrudes from the surface of each of the frames from the −Y direction to the −Y direction, and has such a shape that partially maintains a constant outer diameter and is tapered as approaching the −Y direction. Each of the protrusions is formed of a metal material in the present exemplary embodiment. 
     Further, in the first sub frame  26 , the first supported protrusion  55  is provided in the vicinity of a bearing portion  26   b  (see  FIG.  7   ) that supports the first pulley  8   a.    
     The first supporting hole  40   b  that the first supported protrusion  55  enters is formed in the front frame  40 . The second supporting hole  41   c  that the second supported protrusion  56  enters and the third supporting hole  41   d  that enters the third supported protrusion  57  are formed in the rear frame  41 . 
     The first supporting hole  40   b  is formed in the vicinity of the first opening portion  40   a . Further, the second supporting hole  41   c  and the third supporting hole  41   d  are formed in the vicinity of the edge of the opening portion  41   a.    
     Further, when the first supported protrusion  55  enters the first supporting hole  40   b , the motion unit  25  is supported on the side close to the front frame  40 . Further, when the second supported protrusion  56  enters the second supporting hole  41   c , and the third supported protrusion  57  enters the third supporting hole  41   d , the motion unit  25  is supported on the side close to the rear frame  41 . 
     Note that, in the present exemplary embodiment, the third supporting hole  41   d  is formed so as to be an elongated hole in the F-axis direction, and is configured to cancel variation of the distance between the second supported protrusion  56  and the third supported protrusion  57  in the F-axis direction. With this, even when the distance between the second supported protrusion  56  and the third supported protrusion  57  in the F-axis direction varies, the motion unit  25  can be mounted to the rear frame  41  as appropriate. 
     Further, in the present exemplary embodiment, at least clearance fitting specified in JISB0405 or a gap larger than the clearance fitting is secured for fitting between the first supported protrusion  55  and the first supporting hole  40   b  and fitting between the second supported protrusion  56  and the second supporting hole  41   c . With this, the respective supported protrusions are allowed to move at least within a predetermined range in the Y-axis direction with respect to the respective supporting holes. 
     Further, in the present exemplary embodiment, the motion unit  25  is supported with play in the Y-axis direction. Specifically, as illustrated in  FIG.  4   , the first sub frame  26  of the motion unit  25  is fixed to the front frame  40  in the vicinity of the first supporting hole  40   b  with a stepped screw  60 . Note that, in the present exemplary embodiment, the second sub frame  27  of the motion unit  25  is not coupled to the rear frame  41 . 
     However, the second sub frame  27  of the motion unit  25  may be coupled to the rear frame  41  with a screw or the like. 
     In  FIG.  12   , the stepped screw  60  has a head portion  60   a , a screw portion  60   b , and a cylinder portion  60   c  positioned between the head portion  60   a  and the screw portion  60   b.    
     A screw hole  26   a  is formed in the first sub frame  26  of the motion unit  25 , and the screw portion  60   b  of the stepped screw  60  is screw-fitted into the screw hole  26   a  of the first sub frame  26 . A through hole  40   e  is formed in the front frame  40 , and the cylinder portion  60   c  of the stepped screw  60  is inserted into the through hole  40   e.    
     The inner diameter of the through hole  40   e  is sufficiently larger than the outer diameter of the cylinder portion  60   c , and has such a size that does not hinder relative movement between the cylinder portion  60   c  and the front frame  40  in the Y-axis direction. 
     Further, the length of the cylinder portion  60   c  (the length in the Y-axis direction) is sufficiently larger than the thickness of the front frame  40  (the thickness in the Y-axis direction). In  FIG.  12   , the reference symbol Y 1  indicates play for which the front frame  40  is allowed to move in the −Y direction with respect to the first sub frame  26 , and the reference symbol Y 2  indicates play for which the front frame  40  is allowed to move in the +Y direction with respect to the first sub frame  26 . In the present exemplary embodiment, Y 1 +Y 2  corresponds to secured play. 
     In this manner, the motion unit  25  is coupled to the front frame  40  with the play in the Y-axis direction. 
     Next, with reference to  FIG.  13   , arrangement of the first supported protrusion  55 , the second supported protrusion  56 , and the third supported protrusion  57  is described in detail. 
     In  FIG.  13   , a line T is a liner line coupling a rotation center C 1  of the first pulley  8   a  and a rotation center C 2  of the second pulley  8   b  to each other, and is indicated with the solid line. Further, a line L 1  is a linear line obtained by extending the line T toward upstream, and is indicated with the broken line. Further, a line R 1  is a linear line obtained by extending the line T toward downstream, and is indicated with the broken line. 
     Further, the line L 2  is a linear line obtained by extending a counter surface of the transport belt  7 , which faces the line head  34 , toward upstream, and is indicated with the one-dot chain line. Further, the line R 2  is a linear line obtained by extending the counter surface of the transport belt  7 , which faces the line head  34 , toward downstream, and is indicated with the one-dot chain line. 
     Further, the line L 3  is a linear line obtained by extending a surface of the transport belt  7 , which does not face the line head  34 , toward upstream, and is indicated with the one-dot chain line. Further, the line R 3  is a linear line obtained by extending the surface of the transport belt  7 , which does not face the line head  34 , toward downstream, and is indicated with the one-dot chain line. 
     The reference symbol A 0  indicates an inner region of the transport belt  7 . Further, the reference symbol A 1  indicates an upstream extension region obtained by extending the inner region A 0  toward upstream. Further, the reference symbol A 2  indicates a downstream extension region obtained by extending the inner region A 0  toward downstream. The upstream extension region A 1  is a region sandwiched between the line L 2  and the line L 3 , and the downstream extension region A 2  is a region sandwiched between the line R 2  and the line R 3 . Note that the inner region A 0  is a region in the first sub frame  26 , and the upstream extension region A 1  and the downstream extension region A 2  are regions in the second sub frame  27 . 
     As illustrated, the first supported protrusion  55  being a component of the motion unit  25  that is supported by the front frame  40  is positioned on the inner side of the inner region A 0 , which is the inner side of the transport belt  7 , when the transport path of the medium is viewed from a side. The second supported protrusion  56  being a component of the motion unit  25  that is supported by the rear frame  41  is positioned on the inner side of the upstream extension region A 1  when the transport path of the medium is viewed from a side. Further, the third supported protrusion  57  being a component of the motion unit  25  that is supported by the rear frame  41  is positioned on the inner side of the downstream extension region A 2  when the transport path of the medium is viewed from a side. 
     With such a configuration, the following actions and effects can be obtained. Specifically, as described above, in the printer  1 , the apparatus gravity center position M is on the side close to the rear frame  41  with respect to the intermediate position between the front frame  40  and the rear frame  41 . With this, the protruding portion is present on the placement surface G of the apparatus, the front frame  40  is likely to be distorted. 
     Further, the number of components of the motion unit  25  that are supported by the front frame  40  is smaller than the number of components thereof that are supported by the rear frame  41 , and hence distortion of the front frame  40  is less likely to affect the motion unit  25 . With this, even when the front frame  40  is distorted, distortion of the motion unit  25  can be suppressed. Thus, position deviation of the transport belt  7  from the front frame  40  and the rear frame  41  and posture fluctuation can be suppressed, and the medium can be transported as appropriate. 
     Further, when the first supported protrusion  55  being the component of the motion unit  25  that is supported by the front frame  40  is displaced downward due to distortion of the front frame  40 , the second supported protrusion  56  and the third supported protrusion  57  being the components of the motion unit  25  that are supported by the rear frame  41  are also displaced downward. In this case, when the first supported protrusion  55 , and the second supported protrusion  56  and the third supported protrusion  57  are away from each other in the horizontal direction, the motion unit  25  is likely to be twisted and deformed. Thus, posture of the transport belt  7  with respect to the front frame  40  and the rear frame  41  is likely to change. 
     In addition, in the motion unit  25 , when a location where distortion occurs in the motion unit  25  is farther away from the first supported protrusion  55 , the second supported protrusion  56 , and the third supported protrusion  57 , there may be a risk that position deviation of the motion unit  25  from the front frame  40  and the rear frame  41  and posture fluctuation are more significant. Specifically, as the transport belt  7  is at a position farther away from the first supported protrusion  55 , the second supported protrusion  56 , and the third supported protrusion  57 , position deviation of the transport belt  7  from the front frame  40  and the rear frame  41  and posture fluctuation are more significant. 
     Further, when position deviation of the transport belt  7  from the front frame  40  and the rear frame  41  and posture fluctuation are caused, relative position deviation between the transport belt  7  and the medium transport mechanisms (for example, the transport roller pairs  16  and  17 ) provided to the front frame  40  and the rear frame  41  and posture fluctuation are caused. Thus there may be a risk that appropriate transport cannot be performed. 
     However, as described above, when the transport path of the medium is viewed from a side, the first supported protrusion  55  is positioned on the inner side of the inner region A 0 , which is the inner side of the transport belt  7 , the second supported protrusion  56  is positioned on the inner side of the upstream extension region A 1 , and the third supported protrusion  57  is positioned on the inner side of the downstream extension region A 2 . 
     With this, the second supported protrusion  56  and the third supported protrusion  57  are arranged so as to sandwich the first supported protrusion  55  therebetween. Thus, when the first supported protrusion  55  is displaced downward due to distortion of the front frame  40 , twist of the motion unit  25  can be suppressed. 
     Further, the first supported protrusion  55 , the second supported protrusion  56 , and the third supported protrusion  57  are arranged at the positions close to the transport belt  7 . Thus, when distortion occurs in the motion unit  25 , position deviation of the transport belt  7  from the front frame  40  and the rear frame  41  and posture fluctuation can be suppressed. 
     With this, even when the front frame  40  is distorted, the medium can be transported as appropriate. 
     In addition, the line head  34  is at the position facing the transport belt  7 , and hence position deviation of the line head  34  from the front frame  40  and the rear frame  41  and posture fluctuation can also be suppressed. 
     Further, the motion unit  25  is supported at one position being the first supported protrusion  55  on the front frame  40 , and is supported at two positions being the second supported protrusion  56  and the third supported protrusion  57  on the rear frame  41 . The second supported protrusion  56  is positioned on the inner side of the upstream extension region A 1 , and the third supported protrusion  57  is positioned on the inner side of the downstream extension region A 2 . With this, while the motion unit  25  is securely supported by the rear frame  41 , distortion of the front frame  40  can securely be prevented from affecting the motion unit  25 . 
     Further, the first supported protrusion  55  is positioned on the line T being a linear line coupling the rotation center C 1  of the first pulley  8   a  and the rotation center C 2  of the second pulley  8   b  to each other. The second supported protrusion  56  is positioned on the line L 1  being a linear line obtained by extending the line T toward upstream, and the third supported protrusion is positioned on the line R 1  obtained by extending the line T toward downstream. 
     Note that a range F 1  in  FIG.  13    is a region of the line head  34  in the transport direction of the medium. In the present exemplary embodiment, the first supported protrusion  55  is positioned on the outer side of the range F 1 , and may be positioned on the inner side of the range F 1 . With this, when the front frame  40  is distorted, posture fluctuation of the line head  34  with respect to the front frame  40  can be suppressed. Thus, appropriate recording quality can be achieved. 
     Note that, in the present exemplary embodiment, the interval between the first pulley  8   a  and the second supported protrusion  56  in the F-axis direction is equal to the interval between the second pulley  8   b  and the third supported protrusion  57 . 
     Further, in the present exemplary embodiment, the first supported protrusion  55  is provided in the vicinity of the bearing portion  26   b  of the first sub frame  26  that supports the first pulley  8   a.    
     Further, the first supported protrusion  55  is deviated from the intermediate position between the second supported protrusion  56  and the third supported protrusion  57  in the F-axis direction, and may be arranged at the intermediate position. 
     Further, in the present exemplary embodiment, the first supported protrusion  55  is positioned on the inner side of the inner region A 0 . However, a part of the first supported protrusion  55  may be positioned on the outer side of the inner region A 0 , or the entire first supported protrusion  55  may be positioned in the vicinity of the outer side of the inner region A 0 . 
     Further, in the present exemplary embodiment, the second supported protrusion  56  is positioned on the inner side of the upstream extension region A 1 . However, a part of the second supported protrusion  56  may be positioned on the outer side of the upstream extension region A 1 , or the entire second supported protrusion  56  may be positioned in the vicinity of the outer side of the upstream extension region A 1 . 
     Further, in the present exemplary embodiment, the third supported protrusion  57  is positioned on the inner side of the downstream extension region A 2 . However, a part of the third supported protrusion  57  may be positioned on the outer side of the downstream extension region A 2 , or the entire third supported protrusion  57  may be positioned in the vicinity of the outer side of the downstream extension region A 2 . 
     Further, in the present exemplary embodiment, the motion unit  25  is supported at one position on the front frame  40 , and is supported at two positions on the rear frame  41 . However, as a matter of course, the present exemplary embodiment is not limited thereto. Specifically, the number of components of the motion unit  25  that are supported by the front frame  40  is only required to be smaller than the number of components thereof that are supported by the rear frame  41 . 
     Further, the motion unit  25  is coupled to the front frame  40  and the rear frame  41  with the play in the Y-axis direction. With this, even when the front frame  40  or the rear frame  41  is distorted, such distortion is less likely to affect the motion unit  25 . With this, while the position of the motion unit  25  with respect to the front frame  40  and the rear frame  41  is defined, distortion of the front frame  40  can be prevented from affecting the motion unit  25 . Thus, the medium can be transported as appropriate. 
     Further, in the present exemplary embodiment, the play is play in a direction in which the front frame  40  is away from the rear frame  41 . Thus, distortion of the front frame  40  in a direction in which the front frame  40  is away from the rear frame  41  as illustrated in  FIG.  11 B  is less likely to affect the motion unit  25 . 
     Note that, in the present exemplary embodiment, as described with reference to  FIG.  12   , play Y 1  for allowing the front frame  40  to move the −Y direction with respect to the first sub frame  26  and play Y 2  for allowing the front frame  40  to move in the +Y direction with respect to the first sub frame  26  are provided. However, at least the Y 1  is only required to be provided. 
     Further, as described with reference to  FIG.  12   , the motion unit  25  is coupled to the front frame  40  by the stepped screw  60 . The stepped screw  60  has the head portion  60   a , the screw portion  60   b  that is fitted into the screw hole  26   a  of the motion unit  25 , and the cylinder portion  60   c  that has a larger diameter than the screw portion  60   b  and is provided between the head portion  60   a  and the screw portion  60   b . The cylinder portion  60   c  is inserted into the through hole  40   e  formed in the front frame  40 . With this, while the play can be secured, the front frame  40  and the motion unit  25  can easily be coupled to each other. Further, the motion unit  25  can be prevented from falling off from the frame structure body  39 . 
     Note that each of the supported protrusions including the first supported protrusion  55 , the second supported protrusion  56 , and the third supported protrusion  57  has a length at the largest part in the Y-axis direction that is set longer than the dimension of the play in the Y-axis direction. Thus, even when the play allows the motion unit  25  to move in the Y-axis direction with respect to the front frame  40  and the rear frame  41 , the play maintains a state in which the respective supported protrusions described above are appropriately supported by the respective supporting portions. 
     Next, with reference to  FIG.  14    and  FIG.  15   , a recording apparatus according to a second exemplary embodiment is described. A printer  1 A according to the second exemplary embodiment illustrated in  FIG.  14    and  FIG.  15    has a configuration similar to that of the above-mentioned printer  1  according to the first exemplary embodiment, except for a supporting member  70  is included in place of the above-mentioned transport unit  6 . Thus, redundant description is omitted. 
     In  FIG.  14   , the printer  1 A includes the supporting member  70  provided to the position facing the line head  34 . The supporting member  70  is a member that defines an interval between the line head  34  and the medium that passes through the position facing the line head  34 , and is formed by a resin material, for example. 
     In  FIG.  15   , a line L 4  is a linear line obtained by extending, toward upstream, a linear line parallel to the F-axis direction passing through the part of the supporting member  70 , which is closest to the +G direction, and is indicated with the one-dot chain line. Further, the line L 5  is a linear line obtained by extending, toward upstream, a linear line parallel to the F-axis direction passing though the part of the supporting member  70 , which is closest to the −G direction, and is indicated with the one-dot chain line. 
     Further, the line R 4  is a linear line obtained by extending, toward downstream, the linear line parallel to the F-axis direction passing through the part of the supporting member  70 , which is closest to the +G direction, and is indicated with the one-dot chain line. Further, the line R 5  is a linear line obtained by extending, toward downstream, the linear line parallel to the F-axis direction passing though the part of the supporting member  70 , which is closest to the −G direction, and is indicated with the one-dot chain line. 
     The reference symbol B 0  is a region of the supporting member  70 , in other words, a region surrounded by the outline of the supporting member  70  when the medium transport path is viewed from a side, and is shown by hatching. Further, the reference symbol B 1  indicates an upstream extension region obtained by extending the region B 0  of the supporting member  70  toward upstream along the F-axis direction. Further, the reference symbol B 2  indicates a downstream extension region obtained by extending the region B 0  of the supporting member  70  toward downstream along the F-axis direction. The upstream extension region B 1  is a region sandwiched between the line L 4  and the line L 5 , and the downstream extension region B 2  is a region sandwiched between the line R 4  and the line R 5 . Note that the region B 0  of the supporting member  70  is a region in the first sub frame  26 , and the upstream extension region B 1  and the downstream extension region B 2  are regions in the second sub frame  27 . 
     As illustrated, the first supported protrusion  55  being a component of the motion unit  25  that is supported by the front frame  40  is positioned on the inner side of the inner region B 0  of the supporting member  70  when the transport path of the medium is viewed from a side. The second supported protrusion  56  being a component of the motion unit  25  that is supported by the rear frame  41  is positioned on the inner side of the upstream extension region B 1  when the transport path of the medium is viewed from a side. Further, the third supported protrusion  57  being a component of the motion unit  25  that is supported by the rear frame  41  is positioned on the inner side of the downstream extension region B 2  when the transport path of the medium is viewed from a side. 
     With this, similarly to the first exemplary embodiment described above, the second supported protrusion  56  and the third supported protrusion  57  are arranged so as to sandwich the first supported protrusion  55  therebetween. Thus, when the first supported protrusion  55  is displaced downward due to distortion of the front frame  40 , twist of the motion unit  25  can be suppressed. 
     Further, the first supported protrusion  55 , the second supported protrusion  56 , and the third supported protrusion  57  are arranged at the positions close to the supporting member  70 . Thus, when distortion occurs in the motion unit  25 , position deviation of the supporting member  70  from the front frame  40  and the rear frame  41  and posture fluctuation can be suppressed. 
     With this, even when the front frame  40  is distorted, the medium can be transported as appropriate. 
     The present disclosure is not limited to each of the exemplary embodiments described above, and many variations can be made within the scope of the present disclosure as described in the claims. It goes without saying that such variations also fall within the scope of the present disclosure.