Patent Publication Number: US-2021179372-A1

Title: Medium conveying apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of International Application No. PCT/JP2018/034691, filed on Sep. 19, 2013, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     The embodiments discussed herein are related to a medium conveying apparatus. 
     BACKGROUND 
     It is popular to computerize, with use of a scanner device, a plurality of media that are put in a binder. The media put in the binder sometimes include a bound medium that is formed of a plurality of paper documents bound with a staple or a clip. An apparatus that feeds a single bound medium from among a plurality of bound media stacked on a document table, and automatically removes a staple from the fed bound medium has been known. Further, an apparatus that, when feeding a single medium from among a plurality of media stacked on a document table, blows air to end faces of the plurality of media such that the single medium to be fed is appropriately floated has been known (see Japanese Laid-open Patent. Publication No. 2016-130158 and Japanese Laid-open Patent Publication No. 2017-132552). 
     However, bound media are bound with staples at different positions and portions in which the staples are arranged are less likely to be floated; therefore, in some cases, it may be difficult to appropriately feed the sets of bound media. 
     SUMMARY 
     According to an aspect of an embodiment, a medium conveying apparatus includes a feed belt, a suctioner with which a medium of a plurality of media stacked on a document table is auctioned to the feed belt, a driver that moves the feed belt to feed the medium when the medium is being suctioned to the feed belt, a first side blower that blows air at a first airflow rate to a first end face of the medium, a second side blower that blows air at a second airflow rate to a second end face opposite to the first end face of the medium, a first sensor that detects whether the medium has been suctioned to a first portion of the feed belt close to the first end face, a second sensor that detects whether the medium has been suctioned to a second portion of the feed belt close to the second end face, and a controller that controls the first side blower to blow air at a third airflow rate greater than the first airflow rate and the second airflow rate to the first end face when the second sensor detects that the medium has been suctioned to the second portion and the first sensor detects that the medium has not been suctioned to the first portion. 
     The object and advantages of the disclosure will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic side view of an image reading apparatus including a medium conveying apparatus of a first embodiment; 
         FIG. 2  is a perspective view illustrating a first paper feed unit of the medium conveying apparatus of the first embodiment; 
         FIG. 3  is a cross-sectional view of the first paper feed unit of the medium conveying apparatus of the first embodiment; 
         FIG. 4  is a bottom view of the first paper feed unit of the medium conveying apparatus of the first embodiment; 
         FIG. 5  is another cross-sectional view of the first paper feed unit of the medium conveying apparatus of the first embodiment; 
         FIG. 6  is another bottom view of the first paper feed unit of the medium conveying apparatus of the first embodiment; 
         FIG. 7  is a bottom view of the first paper feed unit of the medium conveying apparatus of the first embodiment when a first shutter is located at a first closing position and a second shutter is located at a second closing position; 
         FIG. 3  is a block diagram illustrating the image reading apparatus including the medium conveying apparatus of the first embodiment; 
         FIG. 9  is a flowchart illustrating operation performed by the first paper feed unit of the medium conveying apparatus of the first embodiment; 
         FIG. 10  is a bottom view of the first paper feed unit of the medium conveying apparatus of the first embodiment when a bound medium is moved upward by a plurality of suction pads; 
         FIG. 11  is a cross-sectional view of the bound medium when a bound portion has not been suctioned to the first feed belt; 
         FIG. 12  is a cross-sectional view of the bound medium when a first side blower blows air at a third airflow rate that is greater than a first airflow rate; 
         FIG. 13  is a cross-sectional view of the bound medium after a lapse of a predetermined time since the first side blower has blown air at the third airflow rate that is greater than the first airflow rate; 
         FIG. 14  is a cross-sectional view of the bound medium when the first airflow rate at which air is blown by the first side blower and a second airflow rate at which air is blown by a second side blower blows are equal; 
         FIG. 15  is a perspective view of a first, paper feed unit of a medium conveying apparatus of a second embodiment; 
         FIG. 16  is a cross-sectional view of the first paper feed unit of the medium conveying apparatus of the second embodiment; and 
         FIG. 17  is a cross-sectional view of a plurality of media when a first side blower and a second side blower of a medium conveying apparatus of a third embodiment blows air to both end faces of the media. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Preferred embodiments of the disclosure will be explained with reference to accompanying drawings. Embodiments of a medium conveying apparatus disclosed in the present application will be described below with reference to the drawings. The present disclosure is not limited by the description below. In addition, in the following description, the same components are denoted by the same reference symbols, and the repeated explanation thereof will be omitted. 
     First Embodiment 
     As illustrated in  FIG. 1 , a medium conveying apparatus of the first embodiment is used in an image reading apparatus  1 .  FIG. 1  is a schematic side view of the image reading apparatus  1  including the medium conveying apparatus of the first embodiment. The image reading apparatus  1  includes a document table  2 , an exit tray  3 , and a conveying path  5 . A medium is stacked on the document table  2 . The exit tray  3  is arranged on a downstream side of the document table  2  in a conveying direction  6 . The conveying direction  6  is approximately parallel to a plane along an installation surface on which the image reading apparatus  1  is installed. The conveying path  5  is arranged between the document table  2  and the exit tray  3  and forms a pathway that connects the document table  2  and the exit tray  3 . The conveying path  5  guides a medium fed to the conveying path  5  such that the medium fed to the conveying path  5  is conveyed to the downstream side in the conveying direction  6  along the pathway. 
     The image reading apparatus  1  further includes a first paper feed unit  11 , a processing unit  12 , a conveying mechanism  14 , a second paper feed unit  15 , an unfolding unit  16 , a paper ejection unit  17 , and a reading unit  18 . The first paper feed unit  11  is arranged at an end of the conveying path  5  at the side of the document table  2 . The first paper feed unit  11  detects whether a medium is stacked on the document table  2 . When a plurality of media are stacked on the document table  2 , the first paper feed unit  11  feeds a single medium arranged on the topmost side among the plurality of media stacked or the document table  2  to the conveying path  5  and supplies the medium fed from the document table  2  to the conveying path  5  to the processing unit  12 . When a single medium is stacked on the document table  2 , the first paper feed unit  11  feeds the medium to the conveying path  5  and supplies the medium fed from the document table  2  to the conveying path  5  to the processing unit  12 . 
     The processing unit  12  is arranged on a downstream side of the first paper feed unit  11  on the conveying path  5 , that is, arranged between the first paper feed unit  11  on the conveying path  5  and the exit tray  3 . The processing unit  12  detects whether the medium supplied from the first paper feed unit  11  is a single sheet of medium or a bound medium. The single sheet of medium is formed of a single sheet of paper. The bound medium is formed by binding a plurality of sheets of paper with a binding member. Examples of the binding member include a staple. 
     If it is detected that the medium supplied from the first paper feed unit  11  is a single sheet of medium, the processing unit  12  supplies the single sheet of medium as it is to the conveying mechanism  14 , and, if it is detected that the medium supplied from the first paper feed unit  11  is a bound medium, the processing unit  12  removes a binding member from the bound medium to generate a plurality of sheets of media, and supplies the generated plurality of sheets of media to the conveying mechanism  14 . 
     The conveying mechanism  14  is arranged on a downstream side of the processing unit  12  on the conveying path  5 , that is, arranged between the processing unit  12  and the exit tray  3  on the conveying path. The conveying mechanism  14  supplies the medium supplied from the processing unit  12  to the second paper feed unit  15 . 
     The second paper feed unit  15  is arranged on the downstream side of the conveying mechanism  14  on the conveying path  5 , that is, arranged between the conveying mechanism  14  and the exit tray  3  on the conveying path  5 . The second paper feed unit  15  supplies the medium supplied from the conveying mechanism  14  to the reading unit  18 . 
     The unfolding unit  16  is arranged between the conveying mechanism  14  and the second paper feed unit  15  on the conveying path  5 . If the medium conveyed between the conveying mechanism  14  and the second paper feed unit  15  is a Z-folded medium, the unfolding unit  16  unfolds the Z-folded medium into an approximately flat shape. 
     The paper ejection unit  17  is arranged at an end of the conveying path  5  at the side of the exit tray  2 , that is, arranged on a downstream side of the second paper feed unit  15  on the conveying path  5 . The paper ejection unit  17  stacks the medium supplied from the second paper feed unit  15  onto the exit tray  3 . 
     The reading unit  18  is arranged between the second paper feed unit  15  and the paper ejection unit  17  on the conveying path  5 . The reading unit  18  reads images on both sides of the medium that is conveyed between the second paper feed unit  15  and the paper ejection unit  17  on the conveying path  5 . 
       FIG. 2  is a perspective view illustrating the first paper feed unit  11  of the medium conveying apparatus of the first embodiment. The first paper feed unit  11  includes a document table driver  25 , a first side blower  26 - 1 , a second side blower  26 - 2 , and a plurality of feed belts  21 . The document table driver  25  is arranged under the document table  2  and translates the document table  2  up and down in vertical direction  28 . The vertical direction  28  is perpendicular to a plane along the installation surface on which the image reading apparatus  1  is installed. 
     The first side blower  26 - 1  is arranged on one side of the document table  2  in a width direction. A width direction  23  is parallel to the plane along the installation surface of the image reading apparatus  1  and perpendicular to the conveying direction  6 . The first side blower  26 - 1  blows air to one end face of a medium in the width direction  29  when the medium is stacked on the document table  2 . The first side blower  26 - 1  is switched to any of a first airflow rate mode, a third airflow rate mode, and a fifth airflow rate mode. A third airflow rate is greater than a first airflow mode, and a fifth airflow rate is greater than the third airflow rate. 
     The second side blower  26 - 2  is arranged on the other side of the document table  2  in the width direction  29 . The second side blower  26 - 2  blows air to the other end face of the medium in the width direction  29  when the medium is stacked on the document table  2 . The second side blower  26 - 2  is switched to any of a second airflow rate mode, a fourth airflow rate mode, and a sixth airflow rate mode. A second airflow rate is approximately equal to the first airflow rate. A fourth airflow rate is greater than the second airflow rate, and a sixth airflow rate is greater than the fourth airflow rate. 
     Each of the feed belts  27  is made of a flexible material and formed as a loop-shape band. The plurality of feed belts  27  are arranged above the document table  2  in the vertical direction  28 . 
       FIG. 3  is a cross-sectional view of the first paper feed unit  11  of the medium conveying apparatus of the first embodiment. The first paper feed unit  11  includes a separation blower  30 , a plurality of fixed pulleys  31 , a plurality of suction pads  32 , a suction pad driver  33 , a plurality of suction pad blowers  34 , and a conveying blower  35 . The separation blower  30  is arranged on a downstream side of the document table  2  in the conveying direction  6 . The separation blower  30  is arranged on the downstream side of the document table  2  in the conveying direction  6  and blows air to a downstream end face in the conveying direction  6  of the medium stacked on the document table  2 . 
     The plurality of feed belts  27  are movably stretched around the plurality of fixed pulleys  31 , and accordingly, a lower portion  36  is formed. The lower portion  36  separates an area  37  enclosed by the plurality of feed belts  27  and a space  38  between the plurality of feed belts  27  and the document table  2 . 
     The plurality of suction pads  32  are supported by the conveying path  5  so as to be able to move up and down in the vertical direction  28 . The suction pad driver  33  is formed of an actuator and moves the plurality of suction pads  32  up and down in the vertical direction  28 . The plurality of suction pad blowers  34  are connected to the plurality of suction pads  32 . The conveying blower  35  is arranged in the area  37  enclosed by the plurality of feed belts  27 . 
       FIG. 4  is a bottom view of the first paper feed unit  11  of the medium conveying apparatus of the first embodiment. The plurality of feed belts  27  include a first feed belt  41 - 1 , a second feed belt  41 - 2 , and a plurality of central feed belts  42 . The first feed belt  41 - 1  is arranged at a side close to the first side blower  26 - 1  and includes a plurality of first belt air inlets  43 - 1 . The second feed belt  41 - 2  is arranged at a side close to the second side blower  26 - 2  and includes a plurality of second belt air inlets  43 - 2 . The plurality of central feed belts  42  are arranged between the first feed belt  41 - 1  and the second feed belt  41 - 2 . 
     The plurality of suction pads  32  include a first suction pad  44 - 1  and a second suction pad  44 - 2 . The first suction pad  44 - 1  is arranged between the first feed belt  41 - 1  and the plurality of central feed belts  42 , and includes a first pad air inlet  45 - 1 . The second suction pad  44 - 2  is arranged between the second feed belt  41 - 2  and the plurality of central feed belts  42 , and includes a second pad air inlet  45 - 2 . The plurality of suction pad blowers  34  are connected to the plurality of suction pads  32  and suck air via the first pad air inlet  45 - 1  and the second pad air inlet  45 - 2 . 
     The first, paper feed unit  11  includes a first suction detection sensor  46 - 1 , a second suction detection sensor  46 - 2 , and a paper detection sensor  47 . The first suction detection sensor  46 - 1  is arranged in the vicinity of the lower portion  36  of the first feed belt  41 - 1  in the area  37 , and detects whether the medium has been suctioned to the lower portion  36  of the first feed belt  41 - 1 . The second suction detection sensor  46 - 2  is arranged in the vicinity of the lower portion  36  of the second feed belt  41 - 2  in the area  37 , and detects whether the medium has been suctioned to the lower portion  36  of the second feed belt  41 - 2 . 
     The paper detection sensor  47  is arranged on the downstream side in the conveying direction  6  of the plurality of central feed belts  42  located above the conveying path  5 , and detects whether the medium has been located at a predetermined position on the downstream side in the conveying direction of the plurality of central feed belts  42  on the conveying path  5 . The processing unit  12  is able to convey the medium located at the predetermined position. 
       FIG. 5  is another cross-sectional view of the first paper feed unit  11  of the medium conveying apparatus of the first, embodiment. The first paper feed unit  11  further includes an upper conveying guide  51  and a plurality of shutters  52 . The upper conveying guide  51  is formed in a flat plate shape. The upper conveying guide  51  is arranged in the area  37  so as to be located along the lower portion  36  of the plurality of feed belts  27  and fixed to the conveying path  5 . The plurality of shutters  52  are formed in flat plate shapes. The plurality of shutters  52  are arranged between the lower portion  36  and the upper conveying guide  51  so as to be located along the lower portion  36  of the plurality of feed belts  27 . The plurality of shutters  52  are further supported so as to be able to move translationally in parallel to the width direction  29 . 
       FIG. 6  is another bottom view of the first paper feed unit  11  of the medium conveying apparatus of the first embodiment. The plurality of shutters  52  include a first shutter  53 - 1  and a second shutter  53 - 2 . The first shutter  53 - 1  is arranged on the downstream side of the first suction pad  44 - 1  in the conveying direction  6  and includes a plurality of first guide air inlet communication holes  54 - 1  and a plurality of first belt air inlet communication holes  55 - 1 . The first shutter  53 - 1  is supported to be able to move translationally with respect to the conveying path  5  such that the first shutter  53 - 1  can be located at a first opening position or a first closing position. The second shutter  53 - 2  is arranged on the downstream side of the second suction pad  44 - 2  in the conveying direction  6  and includes a plurality of second guide air inlet communication holes  54 - 2  and a plurality of second belt air inlet, communication holes  55 - 2 . The second shutter  53 - 2  is supported to be able to move translationally with respect to the conveying path  5  such that the second shutter  53 - 2  can be located at a second opening position or a second closing position. 
     The upper conveying guide  51  includes a plurality of first guide air inlets  56 - 1  and a plurality of second guide air inlets  56 - 2 . The plurality of first guide air inlets  56 - 1  are arranged in portions that overlap with the first shutter  53 - 1  on the upper conveying guide  51  and do not overlap with the lower portion  36  of the plurality of feed belts  27 . The plurality of second guide air inlets  56 - 2  are arranged in portions that overlap with the second shutter  53 - 2  on the upper conveying guide  51  and do not overlap with the lower portion  36  of the plurality of feed belts  27 . The upper conveying guide  51  further includes a first belt communication hole and a second belt communication hole (not illustrated). The first belt communication hole communicates with a first belt air inlet formed in the lower portion  36  of the plurality of first belt air inlets  43 - 1 . The second belt communication hole communicates with a second belt air inlet formed in the lower portion  36  of the plurality of second belt air inlets  43 - 2 . 
     The plurality of first guide air inlets  56 - 1  communicate with the plurality of first guide air inlet communication holes  54 - 1  and are opened when the first shutter  53 - 1  is located at the first opening position. The first belt air inlet formed in the lower portion  36  of the plurality of first belt air inlets  43 - 1  communicates with the plurality of first belt air inlet communication holes  55 - 1  and is opened when the first shutter  53 - 1  is located at the first opening position. The plurality of second guide air inlets  56 - 2  communicate with the plurality of second guide air inlet communication holes  54 - 2  and are opened when the second shutter  53 - 2  is located at the second opening position. The second belt air inlet formed in the lower portion  36  of the plurality of second belt air inlets  43 - 2  communicates with the plurality of second belt air inlet communication holes  55 - 2  and is opened when the second shutter  53 - 2  is located at the second opening position. At this time, the conveying blower  35  sucks air from the space  38  via the plurality of first guide air inlets  56 - 1 , the plurality of second guide air inlets  56 - 2 , the plurality of first belt air inlets  43 - 1 , and the plurality of second belt air inlets  43 - 2 . 
       FIG. 7  is a bottom view of the first paper feed unit  11  of the medium conveying apparatus of the first embodiment when the first shutter  53 - 1  is located at the first closing position and the second shutter  53 - 2  is located at the second closing position. When the first shutter  53 - 1  is located at the first closing position, the plurality of first guide air inlets  56 - 1  are closed by overlapping with a portion of the first shutter  53 - 1  where the plurality of first guide air inlet communication holes  54 - 1  are not formed. When the first shutter  53 - 1  is located at the first closing position, the first belt air inlet formed in the lower portion  36  of the plurality of first belt air inlets  43 - 1  is closed by overlapping with a portion other than the plurality of first belt air inlet communication holes  55 - 1  of the first shutter  53 - 1 . When the second shutter  53 - 2  is located at the second closing position, the plurality of second guide air inlets  56 - 2  is closed by overlapping with a certain portion of the second shutter  53 - 2  where the plurality of second guide air inlet communication holes  54 - 2  are not formed. When the second shutter  53 - 2  is located at the second closing position, the second belt air inlet formed in the lower portion  36  of the plurality of second belt air inlets  43 - 2  is closed by overlapping with a portion other than the plurality of second belt air inlet communication holes  55 - 2  of the second shutter  53 - 2 . At this time, even if the conveying blower  35  is activated, air in the space  38  is not sucked via the plurality of first guide air inlets  56 - 1 , the plurality of second guide air inlets  56 - 2 , the plurality of first belt air inlets  43 - 1 , and the plurality of second belt air inlets  43 - 2 . 
     As illustrated in  FIG. 8 , the image reading apparatus  1  further includes a belt driver  61 , a shutter driver  62 , and a control device  63 .  FIG. 8  is a block diagram illustrating the image reading apparatus  1  including the medium conveying apparatus of the first embodiment. The control device  63  controls the belt driver  61  to rotate the plurality of fixed pulleys  31  such that the plurality of feed belts  27  move. The control device  63  controls the shutter driver  62  to move the first shutter  53 - 1  and the second shutter  53 - 2 . 
     The control device  63  is a computer and includes a central processing unit (CPU)  64 , a storage device  65 , an input-output device  66 , a communication interface  67 , and a medium interface  68 . The CPU  64  executes a computer program installed in the control device  63  to perform information processing and control the storage device  65 , the input-output device  66 , the communication interface  67 , and the medium interface  68 . The CPU  64  executes &amp; computer program installed in the control device  63  to further control each of elements provided in the image reading apparatus  1 . Examples of the storage device  65  include a memory, such as a random access memory (RAM) or a read only memory (ROM), a fixed disk device, such as a hard disk, and a solid state drive (SSD). The storage device  65  records therein the computer programs installed in the control device  63 , and records therein information used by the CPU  64 . The input-output device  66  outputs information generated through operation performed by a user to the CPU  64 , and outputs information generated by the CPU  64  such that the information can be recognized by the user. 
     The CPU  64  controls the communication interface  67  and downloads information from other computer connected via a communication line to the control device  63  or transmits information from the control device  63  to other computers. The medium interface  68  is formed to be able to load a non-transitory tangible recording medium  69 . Examples of the recording medium  69  include a semiconductor memory, a magnetic disk, a magneto optical disk, and an optical disk. When the recording medium  69  is loaded, the CPU  64  controls the medium interface  68  and reads information from the recording medium  69  or record information to the recording medium  69 . Meanwhile, the computer programs installed in the control device  63  may be downloaded from other computers via the communication interface  67 , or may be read from the recording medium  69  via the medium interface  68 , 
     Operation of Image Reading Apparatus  1   
     When a user attempts to read images from a plurality of media by using the image reading apparatus  1 , the user stacks the plurality of media on the document table  2  and operates the input-output device  66  of the control device  63  to activate the image reading apparatus  1 . The plurality of media stacked on the document table  2  includes a single sheet of medium or a bound medium. In some cases, the single sheet of medium nay be a Z-folded medium that is folded in a Z-shape. If the image reading apparatus  1  is activated, the control device  63  controls the first paper feed unit  11  to detect whether media are stacked on the document table  2 . If the control device  63  detects that the media are stacked on the document table  2 , the control device  63  controls the first paper feed unit  11  to feed a single medium arranged on the topmost side among the plurality of media stacked on the document table  2  to the conveying path  5 , and supplies the fed medium to the processing unit  12 . 
     The control device  63  further controls the processing unit  12  to detect whether the medium supplied from the first paper feed unit  11  is a bound medium or a single sheet of medium. If it is detected that the medium supplied from the first paper feed unit  11  is a single sheet of medium, the control device  63  controls the processing unit  12  to supply the single sheet of medium as it is to the conveying mechanism  14 , and if it is detected that the medium supplied from the first paper feed unit  11  is a bound medium, the control device  63  controls the processing unit  12  to remove a binding member from the bound medium. 
     The unfolding unit  16  unfolds the medium when the medium conveyed between the conveying mechanism  14  and the second paper feed unit  15  is Z-folded. That is, the Z-folded medium conveyed from the conveying mechanism  14  to the second paper feed unit  15  is unfolded by passing through the unfolding unit  16 , and thereafter supplied to the second paper feed unit  15 . When the medium is supplied from the second paper feed unit  15  to the paper ejection unit  17 , the control device  63  controls the reading unit  18  to read images on both sides of the medium conveyed from the second paper feed unit  15  to the paper ejection unit  17  and record the read images. The control device  63  controls the paper ejection unit  17  to stack the medium supplied from, a separating unit  22  to the paper ejection unit  17  onto the exit tray  3 . 
     The control device  63  repeats the operation as described above until the first, paper feed unit  11  detects that no medium is stacked on the document table  2 . By repeating the operation as described above, the image reading apparatus  1  is able to read respective images of a plurality of media that are stacked on the document table  2 . 
       FIG. 3  is a flowchart illustrating operation performed by the first paper feed unit  11  of the medium conveying apparatus of the first, embodiment. If the image reading apparatus  1  is activated, the control device  63  controls the document table driver  25  to move the document table  2  upward in the vertical direction  28  (Step S 1 ). If the image reading apparatus  1  is activated, the control device  63  further activates the first side blower  26 - 1 , the second side blower  26 - 2 , and the conveying blower  35  (Step  32 ). If the first side blower  26 - 1  is activated, the first side blower  26 - 1  blows air to end faces of the plurality of media at the side close to the first side blower  26 - 1  while the media are stacked on the document table  2 . If the second side blower  26 - 2  is activated, the second side blower  26 - 2  blows air to end faces of the plurality of media at the side close to the second side blower  26 - 2  while the media are stacked on the document table  2 . The control device  63  further controls the belt driver  61  to expose the first suction detection sensor  46 - 1  to the space  38  via the plurality of first belt air inlets  43 - 1 , and expose the second suction detection sensor  46 - 2  to the space  38  via the plurality of second belt air inlets  43 - 2 . 
     The control device  63  controls the shutter driver  62  to locate the first shutter  53 - 1  at the first opening position and the second shutter  53 - 2  at the second opening position. The plurality of first guide air inlets  56 - 1  and the plurality of first belt air inlets  43 - 1  are opened when the first shutter  53 - 1  is located at the first opening position. The plurality of second guide air inlets  56 - 2  and the plurality of second belt air inlets  43 - 2  are opened when the second shutter  53 - 2  are located at the second opening position. The conveying blower  35  sucks air from the space  36  via the plurality of first guide air inlets  56 - 1 , the plurality of first belt air inlets  43 - 1 , the plurality of second guide air inlets  56 - 2 , and the plurality of second belt air inlets  43 - 2  (Step S 3 ). 
     The control device  63  further controls the plurality of suction pad blowers  34  to suck air via the first pad air inlet  45 - 1  of the first suction pad  44 - 1  and the second pad air inlet  45 - 2  of the second suction pad  44 - 2 . The control device  83  further, controls the suction pad driver  33  to move the plurality of suction pads  32  downward such that the plurality of suction pads  32  come into contact with a medium that is arranged on the topmost side among the plurality of media stacked on the document table  2 . The medium contacted with the plurality of suction pads  32  is suctioned to the plurality of suction pads  32 . After the medium is suctioned to the plurality of suction pads  32 , the control device  63  controls the suction pad driver  33  to move the plurality of suction pads  32  upward. The medium being suctioned to the plurality of suction pads  32  comes into contact with the lower portion  36  of the plurality of feed belts  27  due to upward movement of the plurality of suction pads  32 . The medium contacted with the lower portion  36  is suctioned to the lower portion  36  of the plurality of feed belts  27  by the conveying blower  35 . 
     After the plurality of suction pads  32  moved upward, the control device  63  controls the first suction detection sensor  46 - 1  to detect whether the medium is suctioned to the lower portion  36  of the first feed belt  41 - 1 , and controls the second suction detection sensor  46 - 2  to detect whether the medium is suctioned to the lower portion  36  of the second feed belt  41 - 2  (Step  34 ). If the control device  63  detects that the medium is not suctioned to both of the first feed belt  41 - 1  and the second feed belt  41 - 2  (No at Step S 4  and No at Step  35 ), the control device  63  determines that no medium is stacked on the document table  2 . 
     If the control device  63  detects that the medium is not suctioned to the first feed belt  41 - 1 , and detects that the medium is suctioned to the second feed belt  41 - 2  (Yes at Step  35 ), the control device  63  detects a mode of the first side blower  26 - 1 . If the first side blower  26 - 1  has been switched to the first airflow rate mode (No at Step S 6 ), the control device  63  switches the first side blower  26 - 1  to the third airflow rate mode to blow air at the third airflow rate to the medium (Step  37 ). If the first side blower  26 - 1  has been switched to the third airflow rate mode (No at Step S 6 ), the control device  63  switches the first side blower  26 - 1  to the fifth airflow rate mode to blow air at the fifth airflow rate to the medium (Step S 7 ). If the first side blower  26 - 1  has been switched to the fifth airflow rate mode (Yes at Step S 6 ), the control device  63  controls the input-output device  66  to notify the user that an error has occurred. 
     If the control device  63  detects that the medium is not suctioned to the second feed belt  41 - 2 , and detects that the medium is auctioned to the first feed belt  41 - 1  (Yes at Step S 5 ), the control device  63  detects a mode of the second side blower  26 - 2 . If the second side blower  26 - 2  has been switched to the second airflow rate mode (No at Step S 6 ), the control device  63  switches the second side blower  26 - 2  to the fourth airflow rate mode to blow air at the fourth airflow rate to the medium (Step S 7 ). If the second side blower  26 - 2  has been switched to the fourth airflow rate mode (No at Stop  36 ), the control device  63  switches the second side blower  26 - 2  to the sixth airflow rate mode to blow air at the sixth airflow rate to the medium (Step S 7 ). If the second side blower  26 - 2  has been switched to the sixth airflow rate mode (Yes at Step  36 ), the control device  63  controls the input-output device  66  to notify the user that an error has occurred. 
     After the process at Step  37  is performed, the control device  63  repeatedly performs the processes from Step  34 . If the control, device  63  detects that the medium is suctioned to both of the first feed belt  41 - 1  and the second feed belt  41 - 2  (Yes at Step  34 ), the control device  63  controls the belt driver  61  to move the plurality of feed belts  27  (Step S 8 ). The medium suctioned to the plurality of feed belts  27  is conveyed to the downstream side in the conveying direction  6  due to movement of the plurality of feed belts  27 . 
     After the plurality of feed belts  27  started to move, the control device  63  controls the paper detection sensor  47  to detect whether, the medium is located at a predetermined position on the downstream side of the plurality of central feed belts  42  on the conveying path  5  in the conveying direction  6  (Step S 9 ). If the control device  63  does not detect that a leading end of the medium reaches the predetermined position until a lapse of a designated time since start of movement of the plurality of feed belts  27  (No at Step S 9 ), the control device  63  controls the input-output device  66  to notify the user that an error, has occurred. 
     If the control device  63  detects that the leading end of the medium reaches the predetermined position (Yes at Step S 9 ), the control device  63  controls the belt driver  61  to stop movement of the plurality of feed belts  27 , and controls the shutter driver  62  to locate the first shutter  53 - 1  at the first closing position and the second shutter  53 - 2  at the second closing position (Step S 10 ). The plurality of first guide air inlets  56 - 1  and the plurality of first belt air inlets  43 - 1  are closed when the first shutter  53 - 1  is located at the first closing position. The plurality of second guide air inlets  56 - 2  and the plurality of second belt air inlets  43 - 2  are closed when the second shutter  53 - 2  is located at the second closing position. The medium is released from the plurality of feed belts  27  when the plurality of first guide air inlets  56 - 1 , the plurality of first belt air inlets  43 - 1 , the plurality of second guide air inlets  56 - 2 , and the plurality of second belt air inlets  43 - 2  are closed. The medium released from the plurality of feed belts  27  can be conveyed by the processing unit  12 . 
     If the control device  63  detects that the leading end of the medium reaches the predetermined position, the control device  63  further switches the first side blower  26 - 1  to the first airflow rate mode and the second side blower  26 - 2  to the second airflow rate mode (Step S 11 ). After the first side blower  26 - 1  is switched to the first airflow rate mode and the second side blower  26 - 2  is switched to the second airflow rate mode, the control device  63  repeatedly performs the processes from Step S 3  to Step S 11 . By repeatedly performing the processes from Step S 3  to Step S 11 , it is possible to appropriately supply the plurality of media stacked on the document table  2  one by one to the processing unit  12 . 
     When a bound medium  50  is stacked on the document table  2 , the first paper feed unit  11  moves the bound medium  50  up toward the plurality of feed belts  27  by using the plurality of suction pads  32  in the process at Step S 3 .  FIG. 10  is a bottom view of the first paper feed unit  11  of the medium conveying apparatus of the first embodiment when the bound medium  50  is moved upward by the plurality of suction pads  32 . The bound medium  50  is formed by binding a plurality of sheets of paper with a staple  81 . A bound portion  82  of the bound medium  50  on which the staple  81  is put is arranged in the vicinity of the plurality of first belt air inlets  43 - 1  of the first feed belt  41 - 1 . 
     Because the bound portion  82  is bound with the staple  81 , the bound portion  82  is heavier than a single sheet of paper. So, in some cases, if may be difficult to suction the bound portion  82  to the first feed belt  41 - 1  even when air is blown at the first air flow rate by the first side blower  26 - 1  and air is sucked from the plurality of first belt air inlets  43 - 1 .  FIG. 11  is a cross-sectional view of the bound medium  50  when the bound portion  82  is not suctioned to the first feed belt  41 - 1 . In this case, a non-bound portion  83  that is not bound with the staple  81  of the bound medium  50  is separated into a plurality of sheets of paper forming the bound medium  50  due to air blown at the second airflow rate by the second side blower  26 - 2 . A sheet of paper  84  on the topmost side of the bound medium  50  is suctioned to the second feed belt  41 - 2  because the non-bound portion  83  is separated into the plurality of sheets of paper. 
     If the first suction detection sensor  46 - 1  detects that the bound medium  50  is not suctioned to the first feed belt  41 - 1 , the first side blower  26 - 1  blows air at the third airflow rate that is greater than the first airflow rate.  FIG. 12  is a cross-sectional view of the bound medium  50  when the first side blower  26 - 1  blows air at the third airflow rate that is greater than the first airflow rate. The air blows by the first side blower  26 - 1  may enter a lower side of the bound portion  32  when the airflow rate is great. 
       FIG. 15  is a cross-sectional view of the bound medium  50  after a lapse of a predetermined time since the first side blower  26 - 1  has blown air at the third airflow rate greater than the first airflow rate. When air is blown at the third airflow rate by the first side blower  26 - 1 , the bound portion  82  of the bound medium  50  may move upward because air enters the lower side of the bound portion  32 , and may be suctioned to the first feed belt  41 - 1 . Further, because the third airflow rate of the air blown by the first side blower  26 - 1  is greater than the second airflow rate of the second side blower  26 - 2 , air blown by the second side blower  26 - 2  is prevented from entering gaps between the plurality of sheets of paper and the sheets of paper are collected, so that it is possible to appropriately feed the bound medium  50  along with movement of the plurality of feed belts  27 . 
       FIG. 14  is a cross-sectional view of the bound medium  50  when both of the first side blower  26 - 1  and the second side blower  26 - 2  blow air at the third airflow rate. When air is blown at the third airflow rate by both of the first side blower  26 - 1  and the second side blower  26 - 2 , air may enter the gaps between the plurality of sheets of paper in the non-bound portion  83  of the bound medium  50 . If air enters the gaps between the plurality of sheets of paper, the plurality of sheets of paper in the non-bound portion  83  of the bound medium  50  are separated from one another. If the plurality of sheets of paper in the non-bound portion  33  are separated, in some cases, it may be difficult to appropriately feed the bound medium  50  along with movement of the plurality of feed belts  27 . 
     When auctioning the bound medium  50  to the plurality of feed belts  27 , the first paper feed unit  11  is able to cause the bound medium  50  to be suctioned appropriately to the plurality of feed belts  27  by increasing the airflow rate at which air is blown to the bound portion  82  as compared to an airflow rate at which air is blown to the non-bound portion  83 . The first paper feed unit  11  is able to appropriately feed the bound medium  50  by causing the bound medium  50  to be suctioned appropriately to the plurality of feed belts  27 . 
     Effects of Medium Conveying Apparatus of First Embodiment 
     The medium conveying apparatus of the first embodiment includes the plurality of feed belts  27 , the conveying blower  35 , the belt driver  61 , the first side blower.  26 - 1 , the second side blower  26 - 2 , the first auction detection sensor  46 - 1 , the second suction detection sensor  46 - 2 , and the controller. The conveying blower  35  causes a single medium among a plurality of media stacked on the document table  2  to be suctioned to the plurality of feed belts  27 . The belt driver  61  moves the plurality of feed belts  27  to feed the medium while the medium is being suctioned to the plurality of feed belts  27 . The first side blower  26 - 1  blows air to a first end face of the medium. The second side blower  26 - 2  blows air to a second end face formed on an opposite side of the first end face of the medium. The first suction detection sensor  46 - 1  detects whether the medium has been suctioned to the first feed belt  41 - 1  located close to the first end face among the plurality of feed belts  27 . The second suction detection sensor  46 - 2  detects whether the medium has been suctioned to the second feed belt  41 - 2  located close to the second end face among the plurality of feed belts  27 . If it is detected that the medium has been suctioned to the second feed belt  41 - 2  and has not been suctioned to the first feed belt  41 - 1 , the control device  63  controls the first side blower  26 - 1  such that an airflow rate at which air is blown to the first end face is changed. The changed airflow rate is greater than an airflow rate at which air is blown to the first end face by the first, side blower  26 - 1  before the change, and is greater than an airflow rate at which air has been blown to the second end face by the second side blower  26 - 2 . The medium conveying apparatus as described above is able to cause the bound medium  50  to be suctioned appropriately to the plurality of feed belts  27  and feed the bound medium  50 . 
     Furthermore, if air is blown to the first end face at the changed airflow rate and it is detected that the medium is not suctioned to the first feed belt  41 - 1 , the control device  63  of the medium conveying apparatus of the first embodiment changes the airflow rate of the first side blower  26 - 1  to a certain airflow rate that is greater than the changed airflow rate. The medium conveying apparatus as described above is able to reliably cause the bound medium  50  to be suctioned to the plurality of feed belts  27  and feed the bound medium  50 . 
     Moreover, if it is detected that the medium has been suctioned to the first feed belt  41 - 1  and has not been suctioned to the second feed belt  41 - 2 , the control device  63  of the medium conveying apparatus of the first embodiment changes the airflow rate at which air is blown to the second end face. The changed airflow rate at which air is blown to the second end face is greater than the airflow rate at which air is blown to the first end face by the first side blower  26 - 1 , and is greater than the airflow rate at which air is blown to the second end face by the second side blower  26 - 2  before the change. The medium conveying apparatus as described above is able to cause the bound medium  50  to be suctioned appropriately to the plurality of feed belts  27  oven when a binding member for binding the bound medium  50  is arranged in the vicinity of the second feed belt  41 - 2 . 
     Furthermore, the medium conveying apparatus of the first embodiment further includes the plurality of suction pads  32  to which the medium is suctioned by contacting with the medium, and the suction pad driver  33  that moves the plurality of suction pads  32 . The control device  63  controls the suction pad driver  33  such that the medium comes into contact with the plurality of suction pads  32  when the medium is not suctioned to the plurality of suction pads  32 , and such that the medium being suctioned to the plurality of suction pads  32  contacts with the plurality of feed belts  27 . The medium conveying apparatus as described above is able to cause the medium to be suctioned appropriately to the plurality of feed belts  27  and feed the medium. 
     Second Embodiment 
     The medium conveying apparatus of the first embodiment-, as described above includes the plurality of suction pads  32 , but the plurality of suction pads  32  may be omitted. As illustrated in  FIG. 15 , a medium conveying apparatus of a second embodiment is configured such that, the first paper feed unit  11  of the medium conveying apparatus of the first embodiment as described above is replaced with a different first paper feed unit  71 , and other components are the same as those of the medium conveying apparatus of the first embodiment as described above.  FIG. 15  is a perspective view of the first paper feed unit  71  of the medium conveying apparatus of the second embodiment. The first paper feed unit  71  is configured such that the plurality of suction pads  32 , the suction pad driver  33 , and the plurality of suction pad blowers  34  of the first paper feed unit  11  of the medium conveying apparatus of the first embodiment as described above are omitted and the plurality of feed belts  27  are replaced with plurality of different feed belts  72 . 
       FIG. 16  is a cross-sectional view of the first paper feed unit  71  of the medium conveying apparatus of the second embodiment. The first paper feed unit  71  is further configured such that the plurality of fixed pulleys  31  of the first paper feed unit  11  of the medium conveying apparatus of the first embodiment as described above are replaced with a plurality of different fixed pulleys  73 . The plurality of feed belts  72  are stretched around the plurality of fixed pulleys  73 , and accordingly, a lower portion  75  is formed. The lower portion  75  separates an area  76  enclosed by the plurality of feed belts  72  and a space between the plurality of feed belts  72  and the document table  2 . 
     The first, paper feed unit  71  is further configured such that the lower portion  75  is located along another plane that is parallel to a plane along a stacking surface of the document table  2  on which a medium is stacked. The first paper feed unit  71  is able to cause the medium stacked on the document table  2  and the lower portion  75  to fully come close to each other by moving the document table  2  upward. By causing the medium and the lower portion  75  to fully come close to each other, the first paper feed unit  71  is able to cause the medium stacked on the document table  2  to foe suctioned to the lower portion  75  by sucking air by the conveying blower  35 . Therefore, the medium conveying apparatus of the second embodiment is able to cause the bound medium  50  to be suctioned appropriately to the plurality of feed belts  72  and feed the bound medium  50 , similarly to the medium conveying apparatus of the first embodiment as described above. 
     Third Embodiment 
     Each of the first side blower  26 - 1  and the second side blower  26 - 2  of the medium conveying apparatus of the embodiments as described above is switched between modes to change an airflow rate, but need not always be switched between modes. K medium conveying apparatus of a third embodiment is configured in the same manner as a medium conveying apparatus of the first embodiment as described above. In this case, the first side blower  26 - 1  is fixed to the third airflow rate mode and the second side blower  26 - 2  is fixed to the second airflow rate mode. When a user attempts to read images from the bound medium  50  by using an image reading apparatus including the medium conveying apparatus of the third embodiment, the user stacks a plurality of media on the document table  2  such that the bound portion  82  faces the first side blower  26 - 1  side. Similarly to the medium conveying apparatus of the embodiments as described above, the bound medium  50  is suctioned appropriately to a plurality of feed belts of the medium conveying apparatus of the third embodiment because an airflow rate at which air is blown to an end face at the side of the bound portion  82  is greater than an airflow rate at which air is blown to an end face on the opposite side. Therefore, the medium conveying apparatus of the third embodiment is able to cause the bound medium  50  to be suctioned appropriately to the plurality of feed belts and feed the bound medium  50 , similarly to the medium conveying apparatus of the embodiments as described above. 
       FIG. 17  is a cross-sectional view of a plurality of media  91 , for which air is blown to both end faces by the first side blower  26 - 1  and the second side blower  26 - 2  of the medium conveying apparatus of the third embodiment. In the medium conveying apparatus of the third embodiment, even when the plurality of media  91  formed of non-bound media are stacked on the document table  2 , air is blown to the both end faces, and therefore, air is appropriately blown into gaps between the plurality of media  91 . The medium conveying apparatus of the third embodiment is able to appropriately separate the plurality of media  91  by appropriately blowing air into the gaps between the plurality of media  91 . Therefore, the medium conveying apparatus of the third embodiment is able to cause a single medium arranged on the topmost side among the plurality of media  91  to be suctioned appropriately to the plurality of feed belts and feed the medium. 
     The medium conveying apparatus of the embodiments as described above is used in the image reading apparatus, but may be used in a different apparatus. Examples of the different apparatus include a printer. For example, when the medium conveying apparatus is used in a printer, the reading unit  13  is replaced with a printing device. Even when the medium conveying apparatus is used in an apparatus different from the image reading apparatus, it is possible to appropriately feed the bound medium  50  by using the plurality of feed belts. 
     The medium conveying apparatus disclosed herein is able to feed a bound medium appropriately. 
     All examples and conditional language recited herein are intended for pedagogical purposes of aiding the reader in understanding the disclosure and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the disclosure. Although the embodiments of the disclosure have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the disclosure.