Patent Publication Number: US-10322592-B2

Title: Medium transport device, printing apparatus and liquid ejecting apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/129,233 filed on Sep. 26, 2016, entitled “MEDIUM TRANSPORT DEVICE, PRINTING APPARATUS AND LIQUID EJECTING APPARATUS,” which issued as U.S. Pat. No. 9,981,489 on Apr. 29, 2018, which is a 371 of PCT Application Serial No. PCT/JP2015/001792 filed on Mar. 27, 2015, entitled “MEDIUM TRANSPORT DEVICE, PRINTING APPARATUS AND LIQUID EJECTING APPARATUS,” which claims priority to Japanese Patent Application No. 2014-067092, filed Mar. 27, 2014, and Japanese Patent Application No. 2014-067093, filed Mar. 27, 2014, wherein all of the foregoing are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field of the Invention 
     Embodiments of the present invention relate to a medium transport device that transports a medium such as a sheet of paper, a printing apparatus that is provided with such a device, and a liquid ejecting apparatus that ejects a liquid onto a medium. 
     2. Background Art 
     As a medium transport device that transports a medium such as a sheet of paper, a medium transport device that is configured so that an image capture unit is provided in a medium support unit that supports a medium, an image of the texture of a lower surface of a medium that passes over the medium support unit is captured by the image capture unit, and a transport weight of the medium is detected on the basis of the captured image, is known. In the medium transport device, an opening section for irradiating light from the image capture unit toward a lower surface of a medium is formed on a support surface of the medium support unit. Further, a light-transmitting member for allowing the transmission of light while suppressing the entry of foreign substances such as paper powder and dust into the inside of the image capture unit is disposed in the opening section. 
     As this kind of medium transport device, for example, the medium transport device of PTL 1 performs a template matching process that locates a position at which a degree of similarity with an image that was captured on a previous occasion is greatest while moving a template of a rectangular region that is set in advance over an image that is captured on a current occasion in order to detect a transport weight of the medium. That is, the medium transport device of PTL 1 calculates a distance in a transport direction of a position of a template in an image that was captured on a previous occasion and a position of a template in an image that is matched and captured on a current occasion as a transport weight of the medium. 
     As shown in FIG. 4 of PTL 1, in the medium transport device of PTL 1, an upper surface of the light-transmitting member that is disposed in the opening section of the medium support unit is flush with a support surface, and a focal position of the image capture unit is aligned with the support surface. That is, the medium transport device is adjusted so that the focal position of the image capture unit becomes an upper surface of the light-transmitting member. 
     In addition, as a liquid ejecting apparatus that ejects a liquid such as an ink from an ejecting unit onto a medium such as a sheet of paper, a liquid ejecting apparatus that is configured so that an image capture unit is provided in a medium support unit that supports a medium, an image of the texture of a lower surface of a medium that passes over the medium support unit is captured by the image capture unit, and a transport weight of the medium is detected on the basis of the captured image, is known. In this kind of liquid ejecting apparatus, an opening section for irradiating light from the image capture unit toward a lower surface of a medium is formed on a support surface of the medium support unit (for example, refer to PTL 1). 
     In this kind of liquid ejecting apparatus, for example, in a case in which a large amount of liquid is ejected onto a medium from the ejecting unit in the manner of that used during solid printing or the like, there are case in which the medium swells as a result of absorbing a large amount of liquid, and therefore, the medium after printing becomes wavy with respect to the support surface of the medium support unit, and so-called cockling is generated. 
     In such a case, there is a concern that portions of the medium that have become deformed in a bending manner in a direction that rises from the support surface due to the cockling phenomenon will come into contact with the ejecting unit. 
     In such an instance, as shown in  FIG. 9 , in this kind of liquid ejecting apparatus, a plurality of concave sections  102  are formed on a support surface  101  of a medium support unit  100 , and suction holes  103  are formed on the support surface  101  at a plurality of points including a bottom surface region of a portion of the concave sections  102 . Further, it is configured so that the medium is adsorbed to a support surface  101  side by driving a suction fan (not shown in the drawing) that is in communication with each suction hole  103 . 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP-A-2013-119439 
     BRIEF SUMMARY OF THE INVENTION 
     According to the medium transport device of PTL 1, since a focal position of the image capture unit coincides with an upper surface of the light-transmitting member, the focal position of the image capture unit meets foreign substances when foreign substances are attached to the upper surface of the light-transmitting member. As a result of this, since the image capture unit captures images of foreign substances clearly, the effect of foreign substances on an image of the texture of a lower surface of a captured medium is increased. Therefore, in the medium transport device of PTL 1, there is a concern that a template position in an image that is captured on the current occasion that differs from a template position that should be matched will be set as a position at which the degree of similarity is greatest, and therefore, the transport weight of the medium will be calculated when performing the template matching process on the basis of the incorrect template position. Therefore, there is a concern that there will be a deterioration in the precision of detection of the transport weight of a medium. 
     In addition, in the liquid ejecting apparatus of PTL 1, as shown in  FIG. 9 , the light-transmitting member  110  of the image capture unit is disposed between a plurality of concave sections  102  in a width direction of the medium support unit  100 . That is, on the support surface  101  of the medium support unit  100 , a disposition region of the light-transmitting member  110  and a region of a predetermined width that is continuous from the disposition region to a downstream side in the transport direction of the medium becomes a region in which the concave sections  102  are not formed. Therefore, in this region with a predetermined width, it is not possible to support the medium since the medium is displaced further in a direction that becomes separated from the ejecting unit than the support surface  101 , and therefore, in cases in which portions of the medium that have become deformed in a bending manner in a direction that rises from the support surface  101  due to the cockling phenomenon, there is still a concern that the portions will come into contact with the ejecting unit. 
     Embodiments of the invention is made by considering the above-described situations and object thereof is to provide a medium transport device that is capable of suppressing deteriorations in the detection quality of the transport weight of a medium, and a printing apparatus that is provided with such a device. In addition, another advantage of some aspects of the invention is to provide a liquid ejecting apparatus that, in a case in which a light-transmitting member, which transmits light for medium image capture from an image capture unit, is disposed on a support surface of a medium support unit that faces an ejecting unit, can even reduce a concern that portions of a medium that are deformed in a bending manner will come into contact with the ejecting unit in a case in which portions of the medium that are deformed in a bending manner are positioned on the light-transmitting member. 
     Hereinafter, means of the invention, and operational effects thereof will be described. 
     A medium transport device for solving the above-described problems includes a transport unit that transports a medium, an image capture unit that captures an image of the medium that is transported by the transport unit from a first side in a front-rear direction of the medium, and a control unit that detects a transport weight of the medium that is transported by the transport unit on the basis of an image that is captured by the image capture unit, and controls the transport unit on the basis of the transport weight of the medium, in which the image capture unit is provided with an optical member, light-transmitting members which are disposed further on a second side in the front-rear direction of the medium than the optical member, and which transmit light for medium image capture from the image capture unit, and a support member, to which the light-transmitting members are fixed, and which supports the medium further on the second side in the front-rear direction of the medium than the light-transmitting members, and a focal position of the optical member is positioned further on the second side in the front-rear direction of the medium than a surface of the second side of the light-transmitting members. 
     A liquid ejecting apparatus for solving the above-described problems includes a transport unit that transports a medium, an ejecting unit that ejects a liquid onto the medium that is transported by the transport unit, a medium support unit, which has a support surface that is capable of supporting the medium that is transported by the transport unit in a manner in which the medium faces the ejecting unit, and in which a plurality of concave sections, which are indented in a direction that becomes separated from the ejecting unit, are formed in the support surface, and an image capture unit, which is disposed on a side that is opposite to the ejecting unit with the support surface as a reference, and which captures an image of a surface of a side of the medium that is opposite to a surface that faces the ejecting unit, in which opening sections are formed inside the concave sections, and light-transmitting members, which transmit light for medium image capture from the image capture unit, are disposed in the opening sections. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic configuration view of an ink jet type printer of an embodiment. 
         FIG. 1B  is an enlarged view of a pair of paper supply rollers in  FIG. 1A  and the periphery thereof. 
         FIG. 2A  is a plan view of a portion of a medium support unit. 
         FIG. 2B  is an enlarged view of a first concave section and a second concave section in  FIG. 2A . 
         FIG. 3  is a cross-sectional view of a line in  FIG. 1A . 
         FIG. 4  is an enlarged view of a dashed-dotted line circle IV in  FIG. 3 . 
         FIG. 5  is a perspective view of a first concave section and the periphery thereof. 
         FIG. 6  is a cross-sectional view of a portion of the medium support unit. 
         FIG. 7  is a plan view of a portion of the medium support unit. 
         FIG. 8  is a plan view of a portion of a medium support unit of a modification example. 
         FIG. 9  is a plan view of a portion of a medium support unit of the related art. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, an embodiment in which a printing apparatus and a liquid ejecting apparatus have been implemented in an ink jet type printer will be described according to the drawings. 
     As shown in  FIG. 1A , the ink jet type printer (hereinafter, a “printer  11 ”) as an example of a printing apparatus and a liquid ejecting apparatus a transport device  12 , which is an example of a medium transport device that transports long-sheet continuous paper P, which is an example of a medium, and an ejecting unit  17 , which is an example of a printing unit that performs printing by ejecting ink, which is an example of a liquid, onto the continuous paper P that is transported by the transport device  12 . In addition, the printer  11  is provided with control unit  18  that controls the transport device  12  and the ejecting unit  17 . 
     The transport device  12  is provided with a dispatch unit  14  that dispatches the continuous paper P, and a winding unit  15  that winds continuous paper P that is dispatched from the dispatch unit  14  on which printing has been performed by the ejecting unit  17 . In  FIGS. 1A and 1B , while the dispatch unit  14  is disposed in a position that is on a right side of the continuous paper P, which is an upstream side in a transport direction Y (a left direction in  FIGS. 1A and 1B ), the winding unit  15  is disposed in a position that is on a left side thereof, which is a downstream side. 
     The ejecting unit  17  is disposed so as to face a transport pathway of the continuous paper P in a position that is between the dispatch unit  14  and the winding unit  15 . A plurality of nozzles  17   a  for ejecting ink onto the continuous paper P are formed in a surface of the ejecting unit  17  that faces the transport pathway of the continuous paper P. 
     In addition, in the transport device  12 , a medium support unit  20  that supports the continuous paper P is disposed in a position that faces the ejecting unit  17  with the transport pathway of the continuous paper P interposed therebetween. The medium support unit  20  forms a bottomed rectangular box shape in which an open section  21  is formed on a lower surface side that is a side that is opposite to the ejecting unit  17 . 
     A suction fan  28 , which is an example of a suction unit that suctions air inside an internal airspace  22  of the medium support unit  20 , is provided on the lower surface of the medium support unit  20  so as to fill the open section  21 . A surface of the medium support unit  20  that faces the ejecting unit  17  is set as a flat support surface  20   a  that supports the continuous paper P that is transported. A plurality of suction holes  23  for adsorbing the continuous paper P to the support surface  20   a  are formed in the medium support unit  20 . Each suction hole  23  is in communication with the internal airspace  22  of the medium support unit  20 . According to this kind of configuration, an airspace between the continuous paper P and the medium support unit  20  is set to a negative pressure through the internal airspace  22  and the suction holes  23  as a result of air being taken in due to the suction fan  28  being driven in a rotational manner with the open section  21  as an intake opening. As a result of this, a suction force for adsorbing the continuous paper P to the support surface  20   a  is applied to the continuous paper P. 
     An image capture unit  30  for detecting a transport weight of the continuous paper P in a contactless manner is attached to a lower portion of the medium support unit  20 . The image capture unit  30  captures an image of the texture of a lower surface (a non-printing surface) of the continuous paper P, and transmits the image to the control unit  18 , which is attached to a lower portion of the image capture unit  30 . The control unit  18  controls the transport weight of the continuous paper P on the basis of an image from the image capture unit  30  using a well-known technique such as that disclosed in PTL 1, for example. 
     A dispatch shaft  14   a  that extends in a width direction X (a direction that is orthogonal to a paper surface in  FIGS. 1A and 1B ) of the continuous paper P, which is a direction that is orthogonal to the transport direction Y of the continuous paper P, is provided in the dispatch unit  14  in a manner in which the dispatch shaft  14   a  is capable of being driven in a rotational manner. The continuous paper P is supported on the dispatch shaft  14   a  in a state of being wound in roll form in a manner in which the continuous paper P is capable of being rotated integrally with the dispatch shaft  14   a . Further, the continuous paper P is dispatched from the dispatch shaft  14   a  toward a downstream side of the transport pathway of the continuous paper P as a result of the dispatch shaft  14   a  being driven in a rotational manner. 
     A pair of paper supply rollers  13 , which is an example of a transport unit that clamps and guides the continuous paper P that is transported from the dispatch shaft  14   a  to the support surface  20   a , is disposed diagonally downward of the dispatch shaft  14   a . The pair of paper supply rollers  13  is disposed in a position that is adjacent in the transport direction Y to an upstream side end portion of the medium support unit  20  in the transport direction Y. The pair of paper supply rollers  13  includes a paper supply roller  13   a  that is provided in a manner in which the paper supply roller  13   a  is capable of being driven in a rotational manner, and a paper pressing roller  13   b  that is driven by rotation of the paper supply roller  13   a . As shown in  FIG. 1B , a position at which the continuous paper P is interposed by the paper supply roller  13   a  and the paper pressing roller  13   b  is positioned further on an upstream side of the medium support unit  20  than the support surface  20   a.    
     As shown in  FIG. 1A , a tension roller  16  for adjusting the tension of a region of the continuous paper P on which printing has been completed is disposed in the transport pathway of the continuous paper P on a downstream side of the support surface  20   a  in the transport direction Y. The winding unit  15  is disposed on a downstream side of the tension roller  16  in the transport pathway of the continuous paper P. 
     A winding shaft  15   a  that extends in the width direction X of the continuous paper P is provided in the winding unit  15  in a manner in which the winding shaft  15   a  is capable of being driven in a rotational manner. Further, continuous paper P on which printing has been completed that is transported from a side of the tension roller  16  is sequentially wound by the winding shaft  15   a  as a result of the winding shaft  15   a  being driven in a rotational manner. 
     Next, a configuration of the medium support unit  20  will be described in detail using  FIGS. 2A, 2B and 3 . 
     As shown in  FIG. 2A , a plurality of first concave sections  24 , which are examples of the concave sections that are open on a side of the ejecting unit  17  (refer to  FIGS. 1A and 1B ) and indented downward from the support surface  20   a , and a plurality of second concave sections  26 , which, while being indented in the same manner as the first concave sections  24 , have a different shape to the first concave sections  24 , are formed in the medium support unit  20 . 
     Upstream side end portions of the plurality of first concave sections  24  and the plurality of second concave sections  26  in the transport direction Y are formed to be upstream side end portions of the medium support unit  20  in the transport direction Y. 
     As shown in  FIG. 2A , the plurality of first concave sections  24  and the plurality of second concave sections  26  are formed in a printing region of the medium support unit  20  in which ink is ejected toward the continuous paper P by the ejecting unit  17 . The plurality of first concave sections  24  are formed so as to be lined up in the width direction X at a predetermined interval. Meanwhile, the plurality of second concave sections  26  are respectively formed at a plurality of points in which a distance in the width direction X from a single second concave section  26  (hereinafter referred to as the “second concave section  26 K”), which is formed at an end that forms a reference (the right end in  FIG. 2A ), varies depending on each size in the width direction X of a plurality of kinds of continuous paper P for which use in the printer  11  is expected. Additionally, other than the second concave section  26 K, the first concave section  24  are formed on both sides in the width direction X of each second concave section  26 . 
     In addition, supporting walls  27 A that configure boundaries between first concave sections  24  that are adjacent in the width direction X, and support the continuous paper P are formed between first concave sections  24  that are adjacent in the width direction X. The supporting walls  27 A form portions of peripheral walls which configure the first concave sections  24  in which the transport direction Y is a longitudinal direction. In addition, a supporting wall  27 B that configures boundaries between first concave sections  24  and second concave sections  26  that are adjacent in the width direction X, and support the continuous paper P are formed between first concave sections  24  and second concave sections  26  that are adjacent in the width direction X. The supporting walls  27 B form portions of peripheral walls which configure the first concave sections  24  and portions of peripheral walls which configure the second concave sections  26  in which the transport direction Y is a longitudinal direction. A supporting wall  27 C that configures an upstream side end portion of the medium support unit  20  in the transport direction Y is formed in an upstream side end portion in the transport direction Y of all of the first concave sections  24  and the second concave sections  26 . The supporting wall  27 C configures a portion of a peripheral wall that configures the first concave sections  24  and the second concave sections  26  in which the width direction X is a longitudinal direction. Upper surfaces of the supporting walls  27 A, upper surfaces of the supporting walls  27 B, and an upper surface of the supporting wall  27 C configure a portion of the support surface  20   a  of the medium support unit  20 . 
     Ribs  25  that extend toward a downstream side in the transport direction Y are formed inside the first concave sections  24 . 
     The ribs  25  rise up from bottom surfaces  24   a  of the first concave sections  24  toward a side of the ejecting unit  17 . A height dimension from the bottom surfaces  24   a  of the first concave sections  24  to an upper surface of the ribs  25  is the same as a height dimension from the bottom surfaces  24   a  of the first concave sections  24  to the support surface  20   a , and in this respect, upper surfaces of the ribs  25  configure a portion of the support surface  20   a . The ribs  25  extend from an upstream side end portion of the first concave sections  24  in the transport direction Y toward a downstream side. Downstream side end portions of the ribs  25  are positioned further on an upstream side of the first concave sections  24  than central portions thereof in the transport direction Y. In addition, in each first concave section  24  a suction hole  23  is formed further on a downstream side in the transport direction Y than the rib  25 . Therefore, the first concave sections  24  are in communication with the internal airspace  22  (refer to  FIGS. 1A and 1B ) of the medium support unit  20  through the suction hole  23 . 
     As shown in  FIG. 2B , on the inside of two first concave sections  24  that are adjacent in the width direction X and interposed between two second concave sections  26 , an opening section  24   b  is formed in a region that is close to the upstream side in the transport direction Y. A portion of the image capture unit  30  is inserted into the opening section  24   b  from a lower side. That is, the image capture unit  30  captures an image of a lower surface of the continuous paper P through the opening section  24   b . Additionally, in the following description, among the first concave sections  24 , the two first concave sections  24  in which the opening section  24   b  is formed will be referred to as the “first concave section  24 A” and the “first concave section  24 B”. The dimensions in the transport direction Y of the first concave sections  24 A and  24 B are larger than the dimensions in the transport direction Y of other first concave sections  24 . 
     Meanwhile, the second concave sections  26  are set to an open shape that is capable of receiving ink that is ejected onto the continuous paper P from the ejecting unit  17  (refer to  FIGS. 1A and 1B ). The second concave sections  26  have openings in which a width dimension, which is a dimension in the width direction X, is slightly smaller than a width dimension of the first concave sections  24 , and in which a dimension in the transport direction Y is larger than a dimension in the transport direction Y of the first concave sections  24  other than the first concave sections  24 A and  24 B. Additionally, in the following description, the second concave section  26  that is adjacent to the first concave section  24 A in the width direction X will be referred to as the “second concave section  26 A”, and the second concave section  26  that is adjacent to the first concave section  24 B in the width direction X will be referred to as the “second concave section  26 B”. 
     Next, a configuration of the image capture unit  30  will be described in detail using  FIGS. 3 to 5 . 
     As shown in  FIG. 3 , the image capture unit  30  is provided with a cylindrical lens barrel  31  that extends in a vertical direction Z. The lens barrel  31  is fixed to the medium support unit  20  by a screw  38  (refer to  FIG. 2B ) at an upper end part thereof, and is fixed to the control unit  18 , which has a housing, by a screw (not shown in the drawings) at a lower end part thereof. Additionally, in the present embodiment, a front-rear direction of the medium is defined by an upper surface (a front surface) and a lower surface (a rear surface) of the continuous paper P in a position in the transport device  12  in which the image capture unit  30  is provided. The front-rear direction of the medium is a direction along the vertical direction Z. 
     An accommodation unit  31   a , an internal accommodation space of which extends in the transport direction Y is formed in an upper end portion of the lens barrel  31 . The accommodation unit  31   a  is a case in which the top is open, and a lens barrel cover  40 , which is an example of a support member, is attached to the opening thereof so as to fill the opening from an upper side. An upper end portion of the lens barrel cover  40  is inserted into the opening section  24   b  of the first concave sections  24 A and  24 B. A colorless and transparent light-transmitting member  32  for allowing the transmission of light while suppressing the entry of foreign substances such as dust into the inside of the image capture unit  30  is fixed to an upper section of the lens barrel cover  40 . That is, the opening section  24   b  is filled by the light-transmitting member  32 . 
     A light irradiation unit  33  that irradiates a lower surface of the continuous paper P with light is disposed in an airspace that is formed by the accommodation unit  31   a  and the lens barrel cover  40 . The light irradiation unit  33  is a light source such as a light emitting diode of a halogen lamp, and in the present embodiment, is configured by a light emitting diode (LED). The light irradiation unit  33  irradiates light from a lower surface side of the continuous paper P that is transported onto the support surface  20   a  through the light-transmitting member  32  toward the continuous paper P. In this case, the light irradiation unit  33  is disposed so that a lower surface of the continuous paper P is irradiated with light from a side of the width direction X in an oblique manner. 
     An object side lens  34 , which is an example of an optical member that is positioned on an upper side (a side of the medium support unit  20 ), an image side lens  35 , which is an example of an optical member that is positioned on a lower side (a side of the control unit  18 ), and an aperture  36  that is positioned between the object side lens  34  and the image side lens  35 , are accommodated inside the lens barrel  31 . The object side lens  34  is a telecentric lens as one example, and collects reflected light in which light that was output from the light irradiation unit  33  and transmitted by the light-transmitting member  32  has been transmitted by the light-transmitting member  32  again and entered the lens barrel  31  after being reflected by a lower surface of the continuous paper P. The aperture  36  narrows a range of light as a result of light that has passed through the object side lens  34  passing therethrough. The image side lens  35  is a telecentric lens as one example, and collects light that has passed through the aperture  36 . 
     An image capture element  37  which has an image capture surface  37   a  on which an image of a lower surface of the continuous paper P that is collected by the image side lens  35  is imaged, is provided in a lower end portion of the lens barrel  31  that is accommodated in the control unit  18 . The image capture element  37  is, for example, configured by a two-dimensional image sensor. An image that is captured by the image capture unit  30  is output to a control circuit in the control unit  18  for controlling the transport device  12 . 
     As shown in  FIG. 4 , a pair of first wall sections  41 , which is an example of a pair of wall sections that support the light-transmitting member  32 , a second wall section  42  that is formed spaced apart in the width direction X from the pair of first wall sections  41 , and a third wall section  43 , which is a side wall that is connected to the first wall sections  41  and the second wall section  42 , are formed in an upper end portion of the lens barrel cover  40 . In addition, a fourth wall section  44 , which is formed in a position in the width direction X that corresponds to the light irradiation unit  33 , and which configures a portion of an upper wall in the lens barrel cover  40  that is connected to lower portions of the first wall section  41  and the second wall section  42 , is formed in the lens barrel cover  40 . 
     As shown in  FIGS. 4 and 5 , upper surfaces  41   a , which are upper end surfaces of the pair of first wall sections  41 , an upper surface  42   a , which is an upper end surface of the second wall section  42 , and upper surface  43   a , which is an upper end surface of the third wall section  43  are formed to have the same height in the vertical direction Z as the support surface  20   a  of the medium support unit  20 . That is, a dimension in the vertical direction Z (a height dimension Z 1 ) from the bottom surface  24   a  of the first concave sections  24 A to the upper surfaces  41   a  to  43   a  is equivalent to a dimension in the vertical direction Z (a height dimension Z 2 ) from the bottom surface  24   a  of the first concave sections  24 A to the support surface  20   a . Therefore, the upper surfaces  41   a  to  43   a  support the continuous paper P when the continuous paper P is transported on the medium support unit  20 . In addition, the pair of first wall sections  41  protrude on an upper side (the side of the support surface  20   a ) further than an upper surface  32   a  of the light-transmitting member  32 . In other words, the upper surface  32   a  of the light-transmitting member  32  is positioned further on a lower side than the support surface  20   a.    
     Additionally, “the height dimension Z 1  from the bottom surface  24   a  of the first concave sections  24 A to the upper surfaces  41   a  to  43   a  being equivalent to the height dimension Z 2  from the bottom surface  24   a  of the first concave sections  24 A to the support surface  20   a ” includes a range in which the height dimension Z 1  and the height dimension Z 2  are slightly shifted with respect to one another due to processing errors or assembly errors of the lens barrel  31  and the lens barrel cover  40 . In brief, it is suitable if the height dimension Z 1  is substantially the same as the height dimension Z 2 . 
     The light-transmitting member  32  is disposed in an upstream side end portion in the transport direction Y of the first concave sections  24 A. The light-transmitting member  32  is disposed so that the upper surface  32   a  thereof is beneath the bottom surface  24   a  of the first concave section  24 B. A width dimension of the light-transmitting member  32  is half of a width dimension of the first concave sections  24 A. 
     As shown by a dashed line in  FIG. 4 , since the image capture unit  30  captures an image of a lower surface of the continuous paper P clearly, a focal position in the vertical direction Z of the object side lens  34  is set to the support surface  20   a . That is, the focal position of the object side lens  34  is set further on an upper side than the upper surface  32   a  of the light-transmitting member  32 . In addition, an optical axis direction, which is a direction that runs along an optical axis of the object side lens  34  is parallel with the vertical direction Z. Additionally, there are cases in which portions of the continuous paper P that face the light-transmitting member  32  in the vertical direction Z become slightly more warped on a lower side than the support surface  20   a  as a result of the continuous paper P being suctioned by the suction fan  28 . However, as long as a distance in the vertical direction Z between the focal position of the object side lens  34  and a lower surface of the continuous paper P is small, it is possible for the image capture unit  30  to capture an image of a lower surface of the continuous paper P clearly even if the lower surface of the continuous paper P is positioned further on a lower side than the focal position of the object side lens  34  as a result of the lower surface of the continuous paper P being slightly more warped on a lower side than the support surface  20   a.    
     As shown in  FIG. 5 , in the pair of first wall sections  41 , the transport direction Y is a longitudinal direction. Wall sections  41 A and  41 B, which is the pair of first wall sections  41 , are formed spaced apart in the width direction X with the light-transmitting member  32  interposed therebetween. Space are formed at both end portions of the pair of first wall sections  41  in the transport direction Y. An accommodation unit  45  is formed by the lens barrel cover  40  and the supporting wall  27 C between the light-transmitting member  32  and the supporting wall  27 C between the pair of wall sections  41 . The accommodation unit  45  is open at the top thereof, and is formed in a concave shape that is indented downward from the upper surface  32   a  of the light-transmitting member  32 . 
     Among the pair of first wall sections  41 , the wall section  41 A that is on a side of the second concave section  26 A is positioned inside the first concave section  24 A. The wall section  41 A is positioned in a substantially central portion in the width direction X between the supporting wall  27 B that forms a boundary wall between the first concave section  24 A and the second concave section  26 A, and the supporting wall  27 A that forms a boundary wall between the first concave sections  24 A and  24 B. 
     Among the pair of first wall sections  41 , the wall section  41 B that is on a side of the second concave section  26 B configures a portion of the supporting wall  27 A that forms a boundary wall between the first concave sections  24 A and  24 B. The wall section  41 B is configured as an upstream side end portion in the transport direction Y of the supporting wall  27 A of the first concave sections  24 A and  24 B. 
     In the second wall sections  42 , the transport direction Y is a longitudinal direction. The second wall section  42  is positioned in a substantially central portion in the width direction X between the supporting wall  27 A that forms a boundary wall between the first concave sections  24 A and  24 B, and the supporting wall  27 B that forms a boundary wall between the first concave section  24 B and the second concave section  26 B. The second wall section  42  is formed at an upstream side end portion in the transport direction Y of the medium support unit  20 . 
     The third wall section  43  is positioned inside the first concave section  24 B. In the third wall section  43 , the width direction X is the longitudinal direction, and the third wall section  43  is connected to an upstream side end portion in the transport direction Y of the wall section  41 B, and an upstream side end portion in the transport direction Y of the second wall section  42 . A notched portion  24   c  is formed at an upstream side end portion in the transport direction Y of the first concave section  24  in which the third wall section  43  is disposed. The third wall section  43  is disposed in a position inside the first concave section  24  at which the notched portion  24   c  is formed. Further, inside the notched portion  24   c , the third wall section  43  configures a portion of the supporting wall  27 C. 
     The fourth wall section  44 , which is a portion of an upper wall of the lens barrel cover  40  is formed as a surface that is parallel to a flat surface that is formed by the width direction X and the transport direction Y. An upper surface  44   a  of the fourth wall section  44  is flush with the bottom surface  24   a  of the first concave section  24 B. Further, the fourth wall section  44  covers a portion of the opening section  24   b  from an upper side. 
     The suction hole  23  that is formed in the first concave section  24 A is positioned between the pair of first wall sections  41  in the width direction X, and positioned further on a downstream side than the light-transmitting member  32  in the transport direction Y. The suction hole  23  that is formed in the first concave section  24 B is positioned in a central portion of the first concave section  24 B in the width direction X, and positioned further on a downstream side than the fourth wall section  44  of the lens barrel cover  40  in the transport direction Y. The suction hole  23  of the first concave section  24 A is positioned further on an upstream side in the transport direction Y than the suction hole  23  of the first concave section  24 B. 
     In this manner, according to the abovementioned configuration of the medium support unit  20 , and the configurations of the pair of first wall sections  41 , the second wall section  42 , and the third wall section  43  of the lens barrel cover  40 , as shown in  FIG. 6 , it is possible to support the continuous paper P when cockling, which is a phenomenon in which the continuous paper P becomes wavy in the width direction X as a result of the continuous paper P swelling due printing, occurs. 
     More specifically, in first concave sections  24  other the first concave sections  24 A and  24 B and the second concave sections  26 , bent portions of the continuous paper P that are on a side of the ejecting unit  17  (an upper side) are adsorbed to upper surfaces of the supporting walls  27 A to  27 C and upper surfaces of the ribs  25  by the suction fan  28 , and bent portions of the continuous paper P that are on a side of the support surface  20   a  (a lower side) are accommodated in the first concave sections  24  and the second concave sections  26 . Meanwhile, in the first concave sections  24 A and  24 B, bent portions of the continuous paper P that are on a side of the ejecting unit  17  (an upper side) are adsorbed to upper surfaces of the pair of first wall sections  41 , an upper surface of the second wall section  42 , and the supporting walls  27 A to  27 C, and bent portions of the continuous paper P that are on a side of the support surface  20   a  (a lower side) are accommodated in the first concave sections  24 A and  24 B. Therefore, rising of the continuous paper P from the support surface  20   a  on the side of the ejecting unit  17  is suppressed. 
     Next, effects of the printer  11  will be described. 
     As shown in  FIG. 1B , since a position of the continuous paper P that is nipped between the pair of paper supply rollers  13  is positioned above the support surface  20   a  of the medium support unit  20 , the continuous paper P that is transported to the medium support unit  20  by the pair of paper supply rollers  13  enters the support surface  20   a  in a manner in which the continuous paper P intersects the support surface  20   a . As a result of this, it is difficult for the continuous paper P to rise upward from the support surface  20   a  in a region of a predetermined width that is continuous from an upstream side end portion to a downstream side in the transport direction Y in which the continuous paper P intersects the support surface  20   a , and it is easy for the continuous paper P to rise upward from the support surface  20   a  as the continuous paper P runs further toward a downstream side than the region. 
     Meanwhile, the image capture unit  30  is designed so that the focal position of the object side lens  34  coincides with the support surface  20   a  on the premise that the continuous paper P is transported adsorbed to the support surface  20   a . Therefore, if the image capture unit  30  is configured to capture an image of a lower surface of the continuous paper P that is transported to the abovementioned region of a predetermined width, since it is likely that the lower surface of the continuous paper P and the focal position of the object side lens  34  will coincide, it is possible to capture an image of the texture of the lower surface of the continuous paper P clearly. Therefore, it is preferable that the opening section  24   b  for irradiating the lower surface of the continuous paper P with light from the light irradiation unit  33  is formed in the above-mentioned region of a predetermined width, and that the light-transmitting member  32  is positioned inside the opening section  24   b . As the region of a predetermined width, in the present embodiment, the opening section  24   b  is formed at an upstream side end portion in the transport direction Y of the first concave section  24 A. As shown in  FIG. 6 , at the upstream side end portion in the transport direction Y of the first concave section  24 A, the continuous paper P is adsorbed to the support surface  20   a  by the first concave sections  24  and the second concave sections  26 . Therefore, it is difficult for a lower surface of the continuous paper P to rise further upward from the support surface  20   a . Accordingly, it is possible for the image capture unit  30  to capture an image of the texture of the lower surface of the continuous paper P clearly. 
     Further, the upper surface  32   a  of the light-transmitting member  32  is positioned below the support surface  20   a . Therefore, the focal position of the object side lens  34  and the upper surface  32   a  of the light-transmitting member  32  become positions that differ in the vertical direction Z. As a result of this, even if foreign substances such as paper powder of the continuous paper P become adhered to the upper surface  32   a  of the light-transmitting member  32 , the foreign substances do not reach the focal point of the object side lens  34 . Therefore, even if foreign substances appear in a captured image unexpectedly, the texture of the lower surface of the continuous paper P forms a clear image, and therefore, since the foreign substances form an unclear image, the effect of foreign substances on a captured image is reduced. 
     In addition, it becomes more difficult to stabilize the attitude of the continuous paper P that is supported by the support surface  20   a  as the first concave sections  24  become separated from the pair of paper supply rollers  13  (refer to  FIGS. 1A and 1B ) on a downstream side. Therefore, the first concave sections  24  it is preferable that the first concave sections  24  are brought as close to the pair of paper supply rollers  13  as possible, that is, that the first concave sections  24  are provided at an upstream side end portion in the transport direction Y of the medium support unit  20 . 
     In such an instance, in the present embodiment, as shown in  FIG. 5 , the opening section  24   b  for image capture of the lower surface of the continuous paper P by the image capture unit  30  is formed inside the first concave sections  24 A and  24 B, and the light-transmitting member  32  is disposed inside the opening section  24   b . According to this configuration, it is possible to form the first concave sections  24 A and  24 B and the opening section  24   b  in a region of a predetermined width that is continuous from an upstream side end portion to a downstream side in the transport direction Y in which the continuous paper P intersects the support surface  20   a . Therefore, in the region of a predetermined width, it is possible to support and displace the continuous paper P downward. 
     However, since a dimension of the opening section  24   b  in the width direction X is large, in the first concave sections  24 A and  24 B for capturing an image of the continuous paper P using the image capture unit  30 , a portion of the supporting wall  27 A that forms a boundary wall between the first concave sections  24 A and  24 B, and the ribs  25  of the first concave sections  24 A and  24 B are cut away. Therefore, as long as the portion of the supporting wall  27 A and the ribs  25  are in the cut away state, there is a concern that the continuous paper P will not be supported stably by the first concave sections  24 A and  24 B. 
     In such an instance, as shown in  FIG. 6 , in the present embodiment, with respect to the first concave sections  24 A and  24 B, since the wall section  41 B of the first wall section  41  of the lens barrel cover  40  configures an upstream side end portion in the transport direction Y of the supporting wall  27 A, even if a portion of the supporting wall  27 A us cut away as a result of the opening section  24   b  being formed, the upper surface  41   a  of the wall section  41 B supports the continuous paper P. 
     Additionally, in the present embodiment, since the wall section  41 A of the first wall sections  41  and second wall section  42  are positioned in substantially central portions in the width direction X of the first concave sections  24 , and at upstream side end portion in the transport direction Y, the wall section  41 A and the second wall section  42  are provided with the same function as the ribs  25 . Therefore, the upper surface  41   a  of the wall section  41 A and the upper surface  42   a  of the second wall section  42  support the continuous paper P. 
     In this manner, since the wall sections  41 A and  41 B and the second wall section  42  of the lens barrel cover  40  also serve a function of the medium support unit  20  of supporting the continuous paper P, deteriorations in the function of supporting the continuous paper P are suppressed even if the light-transmitting member  32  is positioned at an upstream side end portion in the transport direction Y of the first concave section  24 . 
     According to the printer  11  of the present embodiment, it is possible to obtain the following effects. 
     (1) Since the upper surface  32   a  of the light-transmitting member  32  is positioned below the focal position of the object side lens  34 , even if foreign substances become adhered to the upper surface  32   a  of the light-transmitting member  32 , since the effect of foreign substances on a captured image is small, a circumstance in which an incorrect template position is detected during a template matching process for detecting a transport weight, is suppressed. Therefore, it is possible to suppress deteriorations in the precision of detection of the transport weight of the continuous paper P by the control unit  18 . 
     That is, even if foreign substances become adhered to a surface that is on a second side of the light-transmitting member in the front-rear direction of the medium, the foreign substances are positioned further on a first side in the front-rear direction than a focal position of the optical member. As a result of this, in the front-rear direction of the medium, since the foreign substances that are adhered to a surface that is on a second side of the light-transmitting member do not coincide with the focal position of the optical member, an image of a surface that is on a first side in the front-rear direction of the medium is captured clearly, and an image of the foreign substances is not captured clearly. Therefore, the image capture unit reduces the effect of foreign substances on captured images. Accordingly, it is possible to suppress deteriorations in the precision of detection of the transport weight of the medium on the basis of images of the image capture unit. 
     (2) Since the opening section  24   b  is formed inside the first concave sections  24 A and  24 B, and the light-transmitting member  32  is positioned inside the opening section  24   b , it is possible for the first concave sections  24 , including the first concave sections  24 A and  24 B, to be formed in a region of a predetermined width that is continuous from an upstream side end portion to a downstream side of the medium support unit  20 . Therefore, in the region, since the continuous paper P is deformed downward in a bending manner and supported by the first concave sections  24 A and  24 B even in a case in which there are portions in which the continuous paper P has been deformed in a bending manner in a direction (upward) that rises from the support surface  20   a  due to the cockling phenomenon, it is possible to suppress a circumstance in which the continuous paper P rises from the support surface  20   a . Therefore, in the above-mentioned region of a predetermined width, it is possible to suppress a circumstance in which the continuous paper P and the ejecting unit  17  come into contact with one another. 
     That is, the light-transmitting member, which transmits light for medium image capture from the image capture unit, is disposed in the support surface of the medium support unit inside a concave section that is indented from the support surface on a first side in the front-rear direction of the medium. Therefore, in a case in which the medium is deformed in a bending manner on the support surface, it is possible for portions of the medium that are positioned in a disposition region of the light-transmitting member to be displaced and supported further on the first side in the front-rear direction of the medium than the support surface. Accordingly, even in a case in which portions of the medium that are deformed in a bending manner are positioned on the light-transmitting member, a circumstance in which the portions that are deformed in a bending manner rise from the support surface is suppressed. 
     In addition, the light-transmitting member is disposed in the support surface of the medium support unit inside a concave section that is indented further in a direction that becomes separated from the ejecting unit than the support surface. Therefore, in a case in which the medium is deformed in a bending manner on the support surface, it is possible for portions of the medium that are positioned in a disposition region of the light-transmitting member to be displaced and supported further in a direction that becomes separated from the ejecting unit than the support surface. Accordingly, even in a case in which portions of the medium that are deformed in a bending manner are positioned on the light-transmitting member, a concern that the portions that are deformed in a bending manner will come into contact with the ejecting unit is reduced. 
     (3) When the continuous paper P is transported on the pair of first wall sections  41  of the lens barrel cover  40 , there are cases in which foreign substances such as paper powder of the continuous paper P become adhered to the light-transmitting member  32 . There is a concern that a precision of detection of the transport weight of the continuous paper P will deteriorate if foreign substances that are adhered to the light-transmitting member  32  appear in images captured by the image capture unit  30  unexpectedly. 
     In such an instance, in the present embodiment, in the first concave section  24 A, the suction hole  23  is formed on a downstream side of the light-transmitting member  32  in the transport direction Y. Since the suction fan  28  suctions air between the continuous paper P and the first concave section  24 A through the suction hole  23 , the continuous paper P that faces the light-transmitting member  32  is suctioned. Therefore, air flow toward the downstream side in the transport direction Y is formed between the pair of first wall sections  41 . That is, air flow from the light-transmitting member  32  toward to the suction hole  23  is formed on the upper surface  32   a  of the light-transmitting member  32 . As a result of this, foreign substances that are adhered to the upper surface  32   a  of the light-transmitting member  32  are suctioned into the suction hole  23 . Therefore, foreign substances that are adhered to the upper surface  32   a  of the light-transmitting member  32  are removed. 
     That is, in a case in which the suction unit suctions air that is in an airspace between the light-transmitting member and the medium through the suction hole, air flow from the light-transmitting member toward to the suction hole is formed on a surface of the second side in the front-rear direction of the medium of the light-transmitting member. Therefore, in a case in which foreign substances are adhered to the surface of the second side in the front-rear direction of the medium of the light-transmitting member, the foreign substances are removed from the surface of the second side in the front-rear direction of the medium of the light-transmitting member by the air flow. 
     In addition, since the suction unit suctions air that is in an airspace between the light-transmitting member and the medium through the suction hole, air flow from the light-transmitting member toward the suction hole is created on a surface of the light-transmitting member that faces the ejecting unit. Therefore, in a case in which foreign substances are adhered to the surface of the light-transmitting member that faces the ejecting unit, the foreign substances are removed from the light-transmitting member by the air flow. 
     (4) When a back end portion in the transport direction Y of the continuous paper P passes over the light-transmitting member  32  or the suction hole  23  that are formed in the first concave section  24 A, air inside an airspace that is formed between the continuous paper P and the first concave section  24  is introduced from an opening section that is formed by the back end portion of the continuous paper P and the first concave section  24 A, and is open in the transport direction Y. As a result of this, air flow from an upstream side in the transport direction Y to a downstream side is generated inside the airspace between the continuous paper P and the first concave section  24 . The air flow is guided over the upper surface  32   a  of the light-transmitting member  32  by the pair of first wall sections  41  of the lens barrel cover  40  in the manner that is shown by a dashed-dotted line arrow in  FIG. 7 . As a result of this, the air flow passes over the upper surface  32   a  of the light-transmitting member  32 . Therefore, since foreign substances that are adhered to the upper surface  32   a  of the light-transmitting member  32  move to the downstream side in the transport direction Y due to the air flow, foreign substances are removed from the upper surface  32   a  of the light-transmitting member  32 . 
     That is, when an end portion in the transport direction of the medium passes over the suction hole or the light-transmitting member, air inside an airspace that is formed between the medium and the concave section is introduced from an opening section in the transport direction that is formed by the end portion in the transport direction of the medium and the concave section. Therefore, air flow in the transport direction is generated inside the airspace that is formed between the medium and the concave section. The air flow is guided over a surface of a second side in the front-rear direction of the medium of the light-transmitting member by the pair of wall sections. As a result of this, in a case in which foreign substances are adhered to the light-transmitting member, the foreign substances move toward the transport direction due to the air flow. Accordingly, it is possible to remove foreign substances from the light-transmitting member. 
     In addition, when an end portion in the transport direction of the medium passes over the suction hole or the light-transmitting member, air inside an airspace that is formed between the medium and the concave section is introduced from an opening section in the transport direction that is formed by the end portion in the transport direction of the medium and the concave section. Therefore, air flow in the transport direction is generated inside the airspace that is formed between the medium and the concave section. The air flow is guided over a surface of the light-transmitting member that is on a side of the ejecting unit by the pair of wall sections. As a result of this, in a case in which foreign substances such as dust are adhered to the light-transmitting member, the foreign substances move toward the transport direction due to the air flow. Accordingly, it is possible to remove foreign substances from the light-transmitting member. 
     (5) Side walls that connect end portions in the transport direction Y of the pair of first wall sections  41  to the width direction X are not formed in the pair of first wall sections  41  of the lens barrel cover  40 . According to this configuration, it is possible to remove foreign substances such as paper powder that are adhered to the upper surface  32   a  of the light-transmitting member  32  to further on an upstream side or a downstream side than the light-transmitting member  32  as a result of a user sweeping the upper surface  32   a  of the light-transmitting member  32  using a sweeping member such as a brush or a cotton swab. In addition, since the accommodation unit  45  (refer to  FIG. 5 ) is formed between the light-transmitting member  32  and the medium support unit  20 , it is possible for a user to accommodate foreign substances in the accommodation unit  45  using the sweeping member. Therefore, sweeping of the light-transmitting member  32  is made easier. 
     In addition, as a result of airflow that is generated when the back end portion in the transport direction Y of the continuous paper P passes over the suction hole  23  that is formed in the first concave section  24  passing between the pair of first wall sections  41  as described in (4) above, it is easy for air flow to be introduced over the upper surface  32   a  of the light-transmitting member  32 . Therefore, it is easy to remove foreign substances that are adhered to the upper surface  32   a  of the light-transmitting member  32  using the air flow. 
     (6) Since the wall section  41 A of the first wall section  41  of the lens barrel cover  40  is provided with the same function as the supporting wall  27 A, it is possible to form the first concave sections  24  and the second concave sections  26  at an upstream side end portion in the transport direction Y of the medium support unit  20 , that is, it is possible to form the first concave sections  24  and the second concave sections  26  in positions that are adjacent to the pair of paper supply rollers  13 . Therefore, it is easy to stabilize the attitude of the continuous paper P that is transported onto the support surface  20   a  of the medium support unit  20  by the pair of paper supply rollers  13  in the printing region. 
     That is, in the concave sections, the wall sections of the support member support the medium in place of the peripheral walls that are cut away even in a case in which a portion of the peripheral walls of the concave sections are cut away by the opening section as a result of the opening section being formed in the concave sections. Therefore, an amount by which the medium is bent in a direction that becomes separated from the ejecting unit is reduced. Accordingly, it is possible to suppress deteriorations in the precision of landing positions of liquid. 
     (7) Since the wall section  41 B and the second wall section  42  of the first wall section  41  of the lens barrel cover  40  are provided with the same function as the ribs  25 , it is possible to support the continuous paper P at an upstream side end portion in the transport direction Y of the first concave section  24 A, and it is possible to reduce a downward bending amount of the continuous paper P. 
     (8) Since the focal position of the optical member is set within a range from a position that is further on the second side in the front-rear direction of the medium than a surface of the second side of the light-transmitting member to a surface on which the support member supports the medium, in a case in which the focal position of the optical member coincides with the support surface, when the medium is barely bent from the support surface toward a first side in the front-rear direction of the medium, it is possible for the optical member to be aligned with the focal point of the optical member at a surface on the first side in the front-rear direction of the medium. Therefore, it is possible to capture an image of the medium clearly. In addition, in the front-rear direction of the medium, in a case in which the focal position of the optical member becomes a position that is further on the second side than a surface of the light-transmitting member that is on the second side and a position that is further on the first side than the support surface, it is possible to capture an image of a state in which the medium is bent and deformed from the support surface to the first side in the front-rear direction of the medium. 
     (9) Since the support surface  20   a  of the medium support unit  20  and the upper surfaces  41   a  to  43   a  of each wall sections  41  to  43  are formed to be flush, a circumstance in which a difference in levels is formed between the support surface  20   a  and the upper surfaces  41   a  to  43   a  is suppressed. Therefore, when the continuous paper P is transported over the medium support unit  20 , a circumstance in which the continuous paper P becomes caught in a difference in levels is suppressed. Accordingly, the continuous paper P is transported smoothly. 
     That is, a circumstance in which surfaces of the wall sections of the support member and the support surface of the medium support unit form a difference in levels in the transport direction is suppressed. Therefore, a circumstance in which the medium becomes caught in a difference in levels is suppressed. Accordingly, the medium is transported smoothly. 
     (10) Since the light-transmitting member  32  is positioned below the support surface  20   a  of the medium support unit  20  and the upper surfaces  41   a  to  43   a  of each wall sections  41  to  43 , the light-transmitting member  32  is positioned below the focal point of the object side lens  34  that is set to a position of a lower surface of the continuous paper P, that is, the positions of the support surface  20   a  and the upper surfaces  41   a  to  43   a . Therefore, even if foreign substances are adhered to the light-transmitting member  32 , it is unlikely that the foreign substances will appear in images that are captured by the image capture unit  30 . Accordingly, since it is unlikely that a detection error of the image capture unit  30  will be generated as a result of foreign substances that are adhered to the light-transmitting member  32 , it is possible for the control unit  18  to precisely calculate the transport weight of the continuous paper P. 
     (11) A width dimension, which is a dimension in the width direction X of the supporting wall  27 A that forms a boundary wall between the first concave sections  24 A and  24 B is smaller than a width dimension, which is a dimension in the width direction X of the light-transmitting member  32 . Therefore, in comparison with a configuration in which the width dimension of the supporting wall  27 A is larger than the width dimension of the light-transmitting member  32 , it is easier to accommodate portions of the continuous paper P that are deformed downward in a bending manner, which are adjacent to portions that are deformed in a direction that rises from the support surface  20   a  in a bending manner due the cockling phenomenon, in the first concave sections  24 A and  24 B. Therefore, it is possible to suppress a circumstance in which the continuous paper P rises from the support surface  20   a.    
     Additionally, the abovementioned embodiment may be modified to the following other embodiments. 
     In the abovementioned embodiment, there may be two or more suction holes  23  that is formed inside the first concave sections  24 . 
     In the abovementioned embodiment, as shown in  FIG. 8 , the opening section  24   b  may be formed further on a downstream side than the upstream side end portion in the transport direction Y of the first concave sections  24 A and  24 B. In addition, the opening section  24   b  may be formed in a portion in which a portion of the supporting wall  27 A of the first concave sections  24 A and  24 B has been notched. In this case, the light-transmitting member  32  is disposed so as to extend over the first concave sections  24 A and  24 B. 
     As shown in  FIG. 8 , the opening section  24   b  may be formed on a downstream side in the transport direction Y of the first concave sections  24 A and  24 B, and the suction holes  23  may be formed on both sides of the light-transmitting member  32  in the transport direction Y. The positions of the suction holes  23  in the width direction X are equivalent to positions that are between the pair of first wall sections  41  in the width direction X. 
     According to this configuration, when a front end portion in the transport direction Y of the continuous paper P passes over the suction hole  23  or the light-transmitting member  32  that are on the upstream side of the first concave sections  24 A and  24 B in the transport direction Y, air inside an airspace that is formed between the continuous paper P and the first concave sections  24 A and  24 B is introduced from an opening section that is formed by the front end portion of the continuous paper P and the first concave sections  24 A and  24 B, and is open in the transport direction Y. As a result of this, air flow from a downstream side in the transport direction Y to an upstream side is generated inside the airspace between the continuous paper P and the first concave sections  24 A and  24 B in the manner that is shown by a dashed-dotted line arrow in the drawing. Since foreign substances that are adhered to the upper surface  32   a  move toward the suction hole  23  that is on the upstream side of the first concave sections  24 A and  24 B in the transport direction Y due to the air flow passing over the upper surface  32   a  of the light-transmitting member  32 , foreign substances are removed from the upper surface  32   a.    
     In addition, when a back end portion in the transport direction Y of the continuous paper P passes over the light-transmitting member  32  or the suction hole  23  that are on the downstream side of the first concave sections  24 A and  24 B in the transport direction Y or the light-transmitting member  32 , air inside an airspace that is formed between the continuous paper P and the first concave sections  24 A and  24 B is introduced from an opening section that is formed by the back end portion of the continuous paper P and the first concave sections  24 A and  24 B, and is open in the transport direction Y. As a result of this, air flow from an upstream side in the transport direction Y to a downstream side is generated inside the airspace between the continuous paper P and the first concave sections  24 A and  24 B. Foreign substances that are adhered to the upper surface  32   a  are removed in the same manner as a result of the air flow passing over the upper surface  32   a  of the light-transmitting member  32 . 
     In the abovementioned embodiment, at least one of the first wall section  41 , the second wall section  42  and the third wall section  43  may be positioned below the support surface  20   a  of the medium support unit  20  within a range in which each wall section  41  to  43  is capable of supporting the continuous paper P. 
     In the abovementioned embodiment, the lens barrel cover  40  may configure the entirety of the first concave sections  24 A and  24 B. 
     In the abovementioned embodiment, one of the pair of first wall sections  41  of the lens barrel cover  40  may be omitted. 
     In the abovementioned embodiment, the second wall section  42  of the lens barrel cover  40  may form a portion of the rib  25  only. 
     In the abovementioned embodiment, the second wall section  42  of the lens barrel cover  40  may be omitted. 
     In the abovementioned embodiment, there may be two or more ribs  25  that are formed in the first concave sections  24 . A plurality of ribs  25  are formed spaced apart in the width direction X. 
     In the abovementioned embodiment, the ribs  25  of the first concave sections  24  may be omitted. 
     In the abovementioned embodiment, a communication section that is in communication with an airspace that is further on a side of the pair of paper supply rollers  13  than the medium support unit  20 , and an airspace between the first concave section  24 A and the continuous paper P may be formed in the supporting wall  27 C that configures the first concave section  24 A. As a result of this, when the continuous paper P is transported, external air is introduced into an airspace between the first concave section  24 A and the continuous paper P through the communication section. Therefore, it is easier for the airflow that is shown by the dashed-dotted line arrow in  FIG. 7  to be generated. 
     In the abovementioned embodiment, the first concave sections  24 A and  24 B may be omitted. In this case, the opening section  24   b  is formed in the support surface  20   a . In addition, the light-transmitting member  32  is disposed further on a lower side than the support surface  20   a  of the medium support unit  20 , that is, a focal position of the object side lens  34 . 
     In the abovementioned embodiment, the focal position of the object side lens  34  may be set within a range of further on an upper side than the upper surface  32   a  of the light-transmitting member  32 , and further on a lower side than the support surface  20   a  of the medium support unit  20 . 
     According to this configuration, when the continuous paper P is suctioned downward by the suction fan  28  through the suction hole  23 , the continuous paper P is bent downward in the first concave section  24 A. Since the image capture unit  30  captures an image of a lower surface of the continuous paper P that is on the first concave section  24 A, the image capture unit  30  captures an image of the continuous paper P that is bent downward. In such an instance, according to this configuration, since the focal position of the object side lens  34  is set further on a lower side than the support surface  20   a , it is possible to align the focal point at the lower surface of the continuous paper P that is bent downward. Therefore, it is possible to capture an image of the texture of the lower surface of the continuous paper P clearly. 
     The printing apparatus is not limited to a printer that is provided with a printing function only, and may be a multifunction machine. Furthermore, the printing apparatus is not limited to a serial printer, and may be a line printer or a page printer. 
     The printing apparatus (medium transport device) may have a configuration in which the winding unit  15  and the tension roller  16  are omitted. 
     The liquid ejecting apparatus may be adopted in a thermal jet printer, or adopted in a solid ink jet printer. 
     The liquid ejecting apparatus may be adopted in a serial printer, may be adopted in a line printer, and may be adopted in a page printer. 
     The liquid ejecting apparatus may have a configuration in which the winding unit  15  and the tension roller  16  are omitted. 
     The medium is not limited to continuous paper, and may be single sheets of paper, a resin film, a metallic foil, a metallic film, a composite film of resin and metal (a laminated film), a fabric, a non-woven fabric, a ceramic sheet or the like. 
     In the abovementioned embodiment, a liquid other than ink may be ejected from the ejecting unit  17  onto the continuous paper P as a minute amount of liquid droplets. As a state of the liquid, it is possible to include granules, tears, and filaments that leave a trail. In addition, the liquid that is referred to in this instance may be any material that is capable of being ejected from the ejecting unit  17 . For example, the liquid may include any substance that is in a state in which the physical properties are in a liquid phase, liquids with high or low viscosities, sols, gel waters, other inorganic solvents, organic solvents, solutions, or fluids such as liquid resins. In addition, the liquid may include not only liquids for which the physical properties are in a single state, and may include liquids in which particles that are made from solid objects such as pigments are dissolved, dispersed or mixed in solvents. In a case in which the liquid is ink, ink can include general aqueous ink and oil-based ink, and various liquid compositions such as gel ink, hot melt ink and the like. 
     The medium transport device is not limited to being provided in a printing apparatus, and may be provided in a processing apparatus in which a process other than printing is carried out. The medium transport device may transport a medium other than continuous paper. For example, the medium transport device may be adopted in a drying apparatus that transports a medium inside drying equipment in order to dry the medium. In addition, the medium transport device may be adopted in a surface processing apparatus that carries surface processing such as coating or a surface improvement process on a medium. In addition, the medium transport device may be adopted in a manufacturing apparatus that carries out punching work on a medium. Furthermore, the medium transport device may be adopted in a plating apparatus that carries out non-electrolytic plating on a medium. The medium transport device may be adopted in a circuit formation apparatus that prints circuits onto a tape-like substrate. The medium transport device may be adopted in a measurement apparatus that acquires a measurement value of the thickness, surface roughness or the like of a medium. Furthermore, the medium transport device may be adopted in a detection apparatus that detects a medium.