Patent Publication Number: US-2023140589-A1

Title: Inkjet recording device

Description:
INCORPORATION BY REFERENCE 
     This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2021-180107 filed on Nov. 4, 2021, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     The present disclosure relates to an inkjet recording device that ejects ink through ink ejection nozzles of a recording head so as to perform recording. 
     As a recording device such as a facsimile machine, a copier, or a printer, an inkjet recording device is widely used, which ejects ink through the nozzles of the recording head to form an image, so that a high definition image can be formed. 
     Such an inkjet recording device has a problem that paper dust generated from a paper sheet as a recording medium might clog the nozzle and cause a nozzle ejection failure (missing dot), resulting in lowering of image quality. 
     SUMMARY 
     An inkjet recording device according to an aspect of the present disclosure includes a conveying unit, a recording unit, a sucking roller, and a sucking device. The conveying unit conveys a paper sheet by use of an endless conveyor belt. The recording unit includes a recording head disposed to face a carrying surface of the conveyor belt so as to eject ink through ink ejection nozzles of the recording head to the paper sheet being conveyed by the conveyor belt. On an upstream side of the recording unit in a sheet conveying direction, the sucking roller makes contact with the paper sheet being conveyed and rotates in that state. The sucking device is joined to the sucking roller. The sucking roller is columnar in outer shape and has many air sucking holes formed in a side surface thereof so that air in a vicinity of the sucking roller is sucked through the air sucking holes by the sucking device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a sectional side view illustrating a schematic structure of a printer according to an embodiment of the present disclosure. 
         FIG.  2    is a sectional side view illustrating a structure of a first belt conveying unit, a recording unit, a second belt conveying unit, and their vicinity of the printer according to this embodiment. 
         FIG.  3    is a plan view from above of the first belt conveying unit and the recording unit of the printer according to this embodiment. 
         FIG.  4    is a block diagram illustrating an example of a control path of the printer according to this embodiment. 
         FIG.  5    is a perspective view illustrating an example of a sucking roller used in the printer according to this embodiment. 
         FIG.  6    is a cross-sectional view of a roller main body of the sucking roller shown in  FIG.  5    as cut in a direction orthogonal to an axial direction thereof. 
         FIG.  7    is a sectional side view illustrating a flow path of an airflow, which includes the sucking roller and a sucking device used in the printer according to this embodiment. 
         FIG.  8    is a perspective view illustrating a modification example of the sucking roller used in the printer according to this embodiment. 
         FIG.  9    is a cross-sectional view of a roller main body of the sucking roller shown in  FIG.  8    as cut in a direction orthogonal to an axial direction thereof. 
         FIG.  10    is a perspective view illustrating another modification example of the sucking roller used in the printer according to this embodiment. 
         FIG.  11    is a cross-sectional view of a roller main body of the sucking roller shown in  FIG.  10    as cut in a direction orthogonal to an axial direction thereof. 
         FIG.  12    is a perspective view illustrating still another modification example of the sucking roller used in the printer according to this embodiment. 
         FIG.  13    is a cross-sectional view of a roller main body of the sucking roller shown in  FIG.  12    as cut in a direction orthogonal to an axial direction thereof. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, an embodiment of the present disclosure is described with reference to the drawings.  FIG.  1    is a view illustrating a schematic configuration of a printer  100  of an inkjet recording method according to an embodiment of the present disclosure.  FIG.  2    is a sectional view illustrating a structure of a first belt conveying unit  5 , a recording unit  9 , a second belt conveying unit  12 , and their vicinity of the printer  100  illustrated in  FIG.  1   .  FIG.  3    is a plan view from above of the first belt conveying unit  5  and the recording unit  9  of the printer  100  illustrated in  FIG.  1   . 
     As illustrated in  FIG.  1   , the printer  100  includes a sheet feed cassette  2   a  as a sheet housing unit disposed on the lower side in a printer main body  1 , and a manual sheet feeding tray  2   b  is provided outside a right side surface of the printer main body  1 . A sheet feeding device  3   a  is disposed downstream of the sheet feed cassette  2   a  in a sheet conveying direction, i.e. on the upper right side of the sheet feed cassette  2   a  in  FIG.  1   . In addition, a sheet feeding device  3   b  is disposed downstream of the manual sheet feeding tray  2   b  in the sheet conveying direction. i.e. on the left side of the manual sheet feeding tray  2   b  in  FIG.  1   . The sheet feeding devices  3   a  and  3   b  enable to separate and feed paper sheets (sheets) P one by one. 
     In addition, a first sheet conveying path  4   a  is provided inside the printer  100 . The first sheet conveying path  4   a  is positioned on the upper right side of the sheet feed cassette  2   a , i.e. on the left side of the manual sheet feeding tray  2   b . The paper sheet P sent out from the sheet feed cassette  2   a  passes through the first sheet conveying path  4   a  and is conveyed vertically upward along the side surface of the printer main body  1 . The paper sheet sent out from the manual sheet feeding tray  2   b  passes through the first sheet conveying path  4   a  and is conveyed substantially horizontally to the left. 
     A registration roller pair  13  is provided at a downstream end of the first sheet conveying path  4   a  in the sheet conveying direction. Further, the first belt conveying unit (conveying unit)  5  and the recording unit  9  are disposed near the registration roller pair  13  on the downstream side. The registration roller pair  13  corrects a skew of the paper sheet P, and sends out the paper sheet P to the first belt conveying unit  5  in synchronization with an ink ejection operation by the recording unit  9 . 
     In addition, between the registration roller pair  13  and the first belt conveying unit  5 , there is disposed a contact image sensor (CIS)  20  as a sheet detection sensor for detecting an end position of the paper sheet P in its width direction (in a direction perpendicular to the sheet conveying direction). 
     The first belt conveying unit  5  includes an endless first conveyor belt  8  (see  FIG.  2   ) stretched around a first drive roller  6  and a first driven roller  7 . The paper sheet P sent out from the registration roller pair  13  passes below the recording unit  9 , in the state where it is sucked and held on a carrying surface  8   a  of the first conveyor belt  8 . 
     A sucking roller  60  is disposed upstream of the recording unit  9  in the sheet conveying direction and at a position facing an upstream end of the first conveyor belt  8 . The sucking roller  60  makes contact with the carrying surface  8   a  of the first conveyor belt  8  or the paper sheet P placed on the carrying surface  8   a  so as to be conveyed, and rotates in that state following rotation of the first conveyor belt  8 . A detailed configuration of the sucking roller  60  will be described later. 
     A plate-shaped member  25  is disposed between the recording unit  9  and the sucking roller  60 . The plate-shaped member  25  is secured to a head housing  10  holding line heads  11 C,  11 M,  11 Y, and  11 K and is disposed substantially parallel to the carrying surface  8   a  of the first conveyor belt  8  at a predetermined gap therefrom. The plate-shaped member  25  faces the first conveyor belt  8  over an entire area in a width direction thereof (a direction perpendicular to a plane on which  FIG.  2    is drawn), and a space is formed between a lower surface of the plate-shaped member  25  and the carrying surface  8   a.    
     A first sheet sucking unit  30  is provided at a location facing a backside of the carrying surface  8   a  of the first conveyor belt  8 , inside the loop of the first conveyor belt  8 . The first sheet sucking unit  30  has many holes  30   a  formed in an upper surface thereof for sucking air, and inside the first sheet sucking unit  30 , there is provided a first fan  30   b  that can suck air downward through the upper surface. In addition, the first conveyor belt  8  also has many air holes  8   b  for sucking air (see  FIG.  3   ). With the configuration described above, the first belt conveying unit  5  conveys the paper sheet P while sucking and holding the same on the carrying surface  8   a  of the first conveyor belt  8 . 
     The recording unit  9  includes the line heads  11 C,  11 M,  11 Y, and  11 K that perform recording of an image on the paper sheet P being conveyed while sucked and held on the carrying surface  8   a  of the first conveyor belt  8 . Inks in the line heads  11 C to  11 K are sequentially ejected therefrom to the paper sheet P sucked on the first conveyor belt  8  so as to correspond to information of image data received from an external computer or the like. With this configuration, four color inks of cyan, magenta, yellow, and black are superimposed so that a full-color image is recorded on the paper sheet P. The printer  100  can also record a monochrome image. 
     As illustrated in  FIG.  3   , the recording unit  9  includes the head housing  10  and the line heads  11 C,  11 M,  11 Y, and  11 K held by the head housing  10 . Each of the line heads  11 C to  11 K has a recording area of a width not smaller than that of the paper sheet P conveyed thereto. Each of the line heads  11 C to  11 K is supported at a height to form a predetermined gap (for example, 1 mm) between itself and the carrying surface  8   a  of the first conveyor belt  8  and includes three recording heads  17   a  to  17   c  arranged in a zigzag manner along a sheet width direction (a B-B′ direction) orthogonal to the sheet conveying direction. Many ink ejection nozzles  18  are arranged in an ink ejection surface of each of the recording heads  17   a  to  17   c.    
     The recording heads  17   a  to  17   c  constituting each of the line heads  11 C to  11 K are supplied with ink of the corresponding color among the four color inks (cyan, magenta, yellow, and black color inks), which are respectively stored in ink tanks (not shown). 
     Each of the recording heads  17   a  to  17   c  can eject ink through the ink ejection nozzles  18  corresponding to print positions in accordance with image data received from an external computer or the like, to the paper sheet P being conveyed while sucked and held on the carrying surface  8   a  of the first conveyor belt  8 . With this configuration, the cyan, magenta, yellow, and black color inks are superimposed so that a color image is formed on the paper sheet P on the first conveyor belt  8 . 
     On the downstream side (the left side in  FIG.  1   ) of the first belt conveying unit  5  in the sheet conveying direction, there is disposed the second belt conveying unit  12 . The paper sheet P with the image recorded in the recording unit  9  is sent to the second belt conveying unit  12 , and passes through the second belt conveying unit  12  while the inks on a surface of the paper sheet P are dried. 
     The second belt conveying unit  12  includes an endless second conveyor belt  40  stretched around a second drive roller  41  and a second driven roller  42 . The second conveyor belt  40  is driven by the second drive roller  41  to turn in a counterclockwise direction in  FIG.  2   . The paper sheet P with the image recorded in the recording unit  9  is conveyed by the first belt conveying unit  5  in an arrow X direction, transferred to the second conveyor belt  40 , and is conveyed in an arrow Z direction in  FIG.  2   . 
     A second sheet sucking unit  43  is provided at a location facing a backside of a carrying surface  40   a  of the second conveyor belt  40 , inside the loop of the second conveyor belt  40 . The second sheet sucking unit  43  has many holes  43   a  formed in an upper surface thereof for sucking air, and inside the second sheet sucking unit  43 , there is provided a second fan  43   b  that can suck air downward through the upper surface. In addition, the second conveyor belt  40  also has many air holes for sucking air (not shown). With the configuration described above, the second belt conveying unit  12  conveys the paper sheet P while sucking and holding the same on the carrying surface  40   a  of the second conveyor belt  40 . 
     In addition, a conveyance guide part  50  is provided at a position facing the carrying surface  40   a  of the second conveyor belt  40 . The conveyance guide part  50  constitutes a sheet conveyance path together with the carrying surface  40   a  of the second conveyor belt  40  and suppresses warping or fluttering of the paper sheet P sucked and held on the carrying surface  40   a  by the second sheet sucking unit  43 . 
     A decurler unit  14  is provided downstream of the second belt conveying unit  12  in the sheet conveying direction and in a vicinity of a left side surface of the printer main body  1 . The paper sheet P after the inks are dried in the second belt conveying unit  12  is conveyed to the decurler unit  14 , which corrects a curl of the paper sheet P. 
     On the downstream side (the upper side in  FIG.  1   ) of the decurler unit  14  in the sheet conveying direction, there is provided a second sheet conveying path  4   b . When double-sided recording is not performed, the paper sheet P after passing through the decurler unit  14  is discharged onto a sheet discharge tray  15  provided outside a left side surface of the printer  100 , from the second sheet conveying path  4   b  via a discharge roller pair. When the double-sided recording is performed on the paper sheet P, the paper sheet P, after recording on one side and passing through the second belt conveying unit  12  and the decurler unit  14 , passes through the second sheet conveying path  4   b  and is conveyed to a reverse conveying path  16 . The paper sheet P sent to the reverse conveying path  16  is changed in the conveying direction so as to be upside down, passes through an upper part of the printer  100 , and is conveyed to the registration roller pair  13 . After that, the paper sheet P is conveyed to the first belt conveying unit  5  again, in the state where the side with no image recorded faces upward. 
     In addition, a maintenance unit  19  is disposed below the second belt conveying unit  12 . When performing maintenance of the recording heads  17 , the maintenance unit  19  moves to below the recording unit  9 , wipes ink pushed out (purged) from the ink ejection nozzles  18  (see  FIG.  3   ) of the recording heads  17 , and collects the wiped ink. 
       FIG.  4    is a block diagram illustrating an example of a control path of the printer  100  according to this embodiment. The printer  100  further includes, in addition to the configuration described above, belt drive motors  21  and  22 , fan drive motors  23  and  24 , an operation panel  27 , a storage unit  28 , a communication unit  29 , and a sucking device  70 . 
     The belt drive motors  21  and  22  respectively drive the first drive roller  6  and the second drive roller  41  to rotate, so that the first conveyor belt  8  and the second conveyor belt  40  can turn. The fan drive motors  23  and  24  respectively drive the first fan  30   b  of the first sheet sucking unit  30  and the second fan  43   b  of the second sheet sucking unit  43  to rotate. 
     The operation panel  27  is an operation unit for receiving various setting inputs. For instance, by operating the operation panel  27 , a user can input a size of the paper sheets P set in the sheet feed cassette  2   a  or on the manual sheet feeding tray  2   b , i.e. information of a size of the paper sheet P that is conveyed by the first conveyor belt  8 . In addition, by operating the operation panel  27 , the user can also input the number of the paper sheets P to be printed or instruct a start of a print job. In addition, the operation panel  27  also has a function as a notification device for notifying about an operating state of the printer  100 . 
     The storage unit  28  is a memory for storing an operation program of a control unit  110  and various sets of information, and it includes a read only memory (ROM), a random access memory (RAM), a nonvolatile memory, and the like. The information set by the operation panel  27  is stored in the storage unit  28 . 
     The communication unit  29  is a communication interface for communicating information with an external device (such as a personal computer (PC)). For instance, when the user operates the PC and sends a print command with image data to the printer  100 , the image data and the print command are input to the printer  100  via the communication unit  29 . In the printer  100 , a main control portion  110   a  controls the recording heads  17   a  to  17   c  to eject ink on the basis of the image data, so that an image can be recorded on the paper sheet P. 
     The sucking device  70  is joined to the sucking roller  60  and sucks paper dust of the paper sheet P to be conveyed to the recording unit  9  via the sucking roller  60 . 
     In addition, the printer  100  according to this embodiment includes the control unit  110 . The control unit  110  is constituted of a central processing unit (CPU) and a memory, for example. Specifically, the control unit  110  includes the main control portion  110   a , a sheet suction control portion  110   b , a sheet supply control portion  110   c , and a maintenance control portion  110   d.    
     The main control portion  110   a  controls operations of individual units in the printer  100 . For instance, drive of each roller in the printer  100 , ink ejection from the recording heads  17   a  to  17   c  when recording an image, and the like are controlled by the main control portion  110   a . The main control portion  110   a  also drives the sucking device  70  to remove paper dust of the paper sheet P to be conveyed to the recording unit  9 . 
     The sheet suction control portion  110   b  sends a control signal to the fan drive motors  23  and  24  so as to control rotations of the first fan  30   b  and the second fan  43   b , and thus a state of the paper sheet P sucked and held on the first conveyor belt  8  or the second conveyor belt  40  can be controlled. 
     The sheet supply control portion  110   c  is a recording medium supply control portion that controls the registration roller pair  13  as a recording medium supply unit. For instance, the sheet supply control portion  110   c  controls the registration roller pair  13  based on a detection timing of a rear end of the paper sheet P by the CIS  20 , and thus controls a conveyance timing of the following paper sheet P. 
     The maintenance control portion  110   d  controls the recording heads  17   a  to  17   c  to perform the purge operation described above in which the ink ejection nozzles  18  push out ink in a forced manner. When the maintenance control portion  110   d  controls the recording heads  17   a  to  17   c  to perform the purge operation, it also controls drive of the maintenance unit  19  described above (e.g. movement to below the recording unit  9  and retraction). 
     Note that the control unit  110  may further include a calculation portion that performs necessary calculation and a time measuring portion that measures time. In addition, the main control portion  110   a  may also works as the calculation portion or the time measuring portion described above. 
     As described above, there is the problem that paper dust generated from the paper sheet P might clog the ink ejection nozzles  18  of the recording heads  17  and cause an ink ejection failure (missing dot) of the ink ejection nozzles  18 , resulting in lowering of image quality. Therefore, the printer  100  according to this embodiment uses the sucking roller  60  and the sucking device  70  to suck paper dust of the paper sheet P to be conveyed to the recording unit  9 . 
       FIG.  5    is a perspective view illustrating an example of the sucking roller  60  used in the printer  100  according to this embodiment.  FIG.  6    is a cross-sectional view of a roller main body  61  of the sucking roller  60  shown in  FIG.  5    as cut in a direction (a radial direction) orthogonal to an axial direction thereof.  FIG.  7    is a sectional side view illustrating a flow path of an airflow, which includes the sucking roller  60  and the sucking device  70 , and is also a sectional view of the sucking roller  60  as cut along an axial direction thereof. A left side in  FIG.  7    corresponds to a front side of the printer  100 , and a right side therein corresponds to a rear side of the printer  100 . 
     The sucking roller  60  has a columnar shape and includes the roller main body  61  of a cylindrical shape and a first rotary shaft  62   a  and a second rotary shaft  62   b  that are provided respectively at both ends of the roller main body  61  in the axial direction. The roller main body  61  is hollow and has many air sucking holes  63  formed in an outer circumferential surface (a columnar side surface) thereof. The air sucking holes  63  have a diameter of approximately 1 to 2 mm. 
     The first rotary shaft  62   a  has a hollow cylindrical shape with both ends thereof open and is secured on the rear side in the printer  100 . That is, the first rotary shaft  62   a  is provided at one end of the roller main body  61  in the axial direction. One end of the first rotary shaft  62   a  is inserted into the one end of the roller main body  61  in the axial direction. A first bearing  65   a  is secured to the one end of the roller main body  61  in the axial direction so that the one end of the roller main body  61  in the axial direction is supported so as to be rotatable about the first rotary shaft  62   a  as a support axis. That is, one end of the sucking roller  60  (on the rear side) is supported so as to be rotatable by frictional motion between the first rotary shaft  62   a  and the first bearing  65   a . The sucking device  70  is joined to the roller main body  61  via the first rotary shaft  62   a . Specifically, the other end of the first rotary shaft  62   a  is connected to the sucking device  70 . 
     The second rotary shaft  62   b  is secured to an end (the other end) of the roller main body  61  in the axial direction on the opposite side to the first rotary shaft  62   a  and is rotatably supported by a second bearing  65   b  that is secured on the front side in the printer  100 . That is, the other end of the sucking roller  60  (on the front side) is supported so as to be rotatable by frictional motion between the second rotary shaft  62   b  and the second bearing  65   b.    
     The sucking device  70  includes a sucking fan  71  and a filter  73 . As shown by arrows in  FIG.  7   , the sucking fan  71  sucks air in a vicinity of the sucking roller  60  into the sucking device  70  via the air sucking holes  63  and the first rotary shaft  62   a . The filter  73  is disposed upstream of the sucking fan  71  with respect to a flow path of an airflow and collects paper dust sucked together with the air into the sucking device  70 . The air sucked by the sucking fan  71  is discharged to the outside of the printer  100  via an exhaust duct (not shown). The filter  73  may be disposed downstream of the sucking fan  71  with respect to a flow path of an airflow. 
     At a time of image recording on the paper sheet P, the main control portion  110   a  transmits a control signal to the sucking device  70  so as to drive the sucking fan  71  to rotate. With this configuration, before the paper sheet P fed from the sheet feed cassette  2   a  or the manual sheet feeding tray  2   b  is conveyed to the recording unit  9 , paper dust adhering to the paper sheet P is sucked together with air through the air sucking holes  63  into the sucking roller  60  rotating in contact with the paper sheet P. The paper dust sucked into the sucking roller  60  passes through the first rotary shaft  62   a  and then is collected by the sucking filter  73  in the sucking device  70 . Accordingly, it is possible to reduce paper dust adhering to the paper sheet P to be conveyed to the recording unit  9  and thus to suppress clogging of the ink ejection nozzles  18  caused by paper dust. 
     In addition, between the sucking roller  60  and the recording unit  9 , the plate-shaped member  25  (see  FIG.  2   ) is disposed to face the carrying surface  8   a  of the first conveyor belt  8 , and air that has passed through a space between the plate-shaped member  25  and the carrying surface  8   a  is sucked into the sucking roller  60 . That is, air flows to the sucking roller  60  along a surface of the paper sheet P sucked and held on the carrying surface  8   a , and thus paper dust adhering to the paper sheet P can be efficiently sucked and removed. Here, a gap between the plate-shaped member  25  and the carrying surface  8   a  is set to a value not more than a preset threshold value, and thus it is possible to increase a velocity of an airflow between the plate-shaped member  25  and the carrying surface  8   a  and thus to enhance paper dust sucking efficiency. 
       FIG.  8    is a perspective view illustrating a modification example of the sucking roller  60  used in the printer  100 .  FIG.  9    is a cross-sectional view of a roller main body  61  of the sucking roller  60  shown in  FIG.  8    as cut in a direction (a radial direction) orthogonal to an axial direction thereof. In the modification example shown in  FIG.  8    and  FIG.  9   , many concaves  66  are formed in a surface of the roller main body  61  of the sucking roller  60 . The concaves  66  have a circular shape and are formed at substantially regular intervals in a circumferential direction and an axial direction of the roller main body  61 . The concaves  66  have a diameter of approximately 4 to 5 mm and a depth of approximately 1 mm. Further, air sucking holes  63  are formed in bottom surfaces of the concaves  66 , respectively. As for other parts of the sucking roller  60  and the sucking device  70 , configurations thereof are similar to those shown in  FIG.  5    to  FIG.  7   . 
     When air is sucked through the air sucking holes  63  into the sucking roller  60  at a time of image recording on the paper sheet P, the paper sheet P passing through the sucking roller  60  might be wrapped around the sucking roller  60  under a negative pressure, causing a paper jam. 
     To avoid the above situation, as shown in  FIG.  8    and  FIG.  9   , the concaves  66  are provided in an outer circumferential surface of the roller main body  61 , and the air sucking holes  63  are formed in the bottom surfaces of the concaves  66 , respectively, so that a gap is formed between the paper sheet P being in contact with an outer circumferential surface of the sucking roller  60  and each of the air sucking holes  63 . As a result, a sucking force of the sucking roller  60  with respect to the paper sheet P is reduced, and thus it is possible to suppress a phenomenon in which the paper sheet P is wrapped around the sucking roller  60 . 
       FIG.  10    is a perspective view illustrating another modification example of the sucking roller  60  used in the printer  100 .  FIG.  11    is a cross-sectional view of a roller main body  61  of the sucking roller  60  shown in  FIG.  10    as cut in a direction (a radial direction) orthogonal to an axial direction thereof. In the modification example shown in  FIG.  10    and  FIG.  11   , a plurality of grooves  67  is formed in a surface of the roller main body  61  of the sucking roller  60  so as to extend along the axial direction. The grooves  67  are formed at substantially regular intervals in a circumferential direction of the roller main body  61  and extend up to both ends of the roller main body  61  in the axial direction. The grooves  67  have a groove width of approximately 4 to 5 mm and a depth of approximately 1 mm. Further, a plurality of air sucking holes  63  is formed at constant intervals in a bottom surface of each of the grooves  67 . As for other parts of the sucking roller  60  and the sucking device  70 , configurations thereof are similar to those shown in  FIG.  5    to  FIG.  7   . 
     According to a configuration shown in  FIG.  10    and  FIG.  11   , by the grooves  67 , a gap is formed between the paper sheet P being in contact with an outer circumferential surface of the sucking roller  60  and the air sucking holes  63 . In addition, even in a state where the paper sheet P is in contact with the outer circumferential surface of the sucking roller  60 , air flows into the air sucking holes  63  from both ends of the grooves  67 , and thus there occurs a loss in negative pressure exerted in such a direction as to suck the paper sheet P. As a result, a sucking force of the sucking roller  60  with respect to the paper sheet P is reduced, and thus it is possible to suppress the phenomenon in which the paper sheet P is wrapped around the sucking roller  60 . 
       FIG.  12    is a perspective view illustrating still another modification example of the sucking roller  60  used in the printer  100 .  FIG.  13    is a cross-sectional view of a roller main body  61  of the sucking roller  60  shown in  FIG.  12    as cut in a direction (a radial direction) orthogonal to an axial direction thereof. In the modification example shown in  FIG.  12    and  FIG.  13   , the roller main body  61  is hollow and has many air sucking holes  63  formed in an outer circumferential surface thereof. Further, an elastic layer  68  having an open-cell structure is stacked on the outer circumferential surface of the roller main body  61 . The elastic layer  68  has a thickness of 3 to 5 mm and is made of, for example, polyethylene or polyurethane sponge. As for other parts of the sucking roller  60  and the sucking device  70 , configurations thereof are similar to those shown in  FIG.  5    to  FIG.  7   . 
     According to a configuration shown in  FIG.  12    and  FIG.  13   , by the elastic layer  68 , a gap is formed between the paper sheet P being in contact with an outer circumferential surface of the sucking roller  60  and the air sucking holes  63 . In addition, since the elastic layer  68  has the open-cell structure, even in the state where the paper sheet P is in contact with the outer circumferential surface of the sucking roller  60 , air passes through the elastic layer  68  and flows into the air sucking holes  63 . With this configuration, there occurs a loss in negative pressure exerted in such a direction as to suck the paper sheet P. As a result, a sucking force of the sucking roller  60  with respect to the paper sheet P is reduced, and thus it is possible to suppress the phenomenon in which the paper sheet P is wrapped around the sucking roller  60 . 
     In a case where the sucking roller  60  shown in  FIG.  12    and  FIG.  13    is used for a long period of time, paper dust might be deposited on a surface of the elastic layer  68 , causing deterioration in sucking performance. To avoid this, there may be provided a cleaning mechanism that removes paper dust on the surface of the elastic layer  68 . As the cleaning mechanism, for example, a cleaning brush, a cleaning roller, a scraper, or the like can be used. 
     Other than the above, without being limited to the embodiment described above, the present disclosure can be variously modified within a scope not departing from the spirit thereof. For example, while the above embodiment describes a case where the paper sheet P is conveyed in a state of being sucked by negative-pressure suction on the first conveyor belt  8  and the second conveyor belt  40 , the first conveyor belt  8  and the second conveyor belt  40  may be charged so that the paper sheet P is conveyed in a state of being sucked by electrostatic suction on the first conveyor belt  8  and the second conveyor belt  40  (an electrostatic suction method). 
     In addition, the above embodiment describes the line head type printer  100  as the inkjet recording device, which performs recording with the line heads  11 C to  11 K, each of which includes the recording heads  17   a  to  17   e  having the many ink ejection nozzles  18  arranged in the sheet width direction, but the present disclosure can be similarly applied to a serial type inkjet recording device that performs recording with a recording head  17  that moves over a sheet. 
     The present disclosure can be used for inkjet recording devices that perform recording by ejecting ink through the ink ejection nozzles of the recording head. Using the present disclosure, it is possible to provide the inkjet recording device that can effectively remove paper dust generated from a paper sheet, with a simple configuration.