Patent Publication Number: US-9902581-B2

Title: Paper-sheet transport device

Description:
This application is a National Stage Entry of PCT/JP2015/003794 filed on Jul. 29, 2015, which claims priority from Japanese Patent Application 2014-154774 filed on Jul. 30, 2014, the contents of all of which are incorporated herein by reference, in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a paper-sheet transport device which is applicable to a mechanism for transporting a sheet of paper such as a recording sheet or the like, for example, in an image processing device such as a printer or the like. 
     BACKGROUND ART 
     A sheet transport device, which is used in a printer, a facsimile, or the like and which can transport a recording sheet (hereinafter, referred to as “sheet”) on which an image is printed (recorded), has been developed. For example, PTL (Patent literature) 1 discloses an art which prevents causing a trouble in transporting a sheet by stopping an edge of the sheet to adjust a position and a direction. 
     A main function of the above-mentioned sheet transport device is to feed the sheet one by one out of a sheaf of plural sheets to a reading unit, and to maintain a constant speed of transporting the sheet when feeding the sheet. However, some kind of errors may cause the so-called paper jam that a sheet to be transported remains inside the sheet transport device. Accordingly, in order that a user can remove the remaining sheet, it is necessary to provide the sheet transport device with structure that a part of a transport path can be opened and closed. 
     PTL 2 and PTL 3 disclose an art that, in the case of the paper jam, an edge of the jammed sheet is discharged to a paper discharge port by rotating a paper transport mechanism or the like. 
     CITATION LIST 
     Patent Literature 
     PTL 1 Japanese Patent Application Laid-Open Publication No. 2001-348130 
     PTL 2 Japanese Utility Model Application Laid-Open Publication No. 1988-163951 
     PTL 3 Japanese Patent Application Laid-Open Publication No. 2011-213447 
     SUMMARY OF INVENTION 
     Technical Problem 
     According to the art which is disclosed by PTL 1, in some cases, a transport mechanism may have structure that a subsidiary roller, which forms a pair with a transport roller and rotates cooperatively with the transport roller, is attached to a paper feed cover. In the case of the above-mentioned structure, a user draws a sheet from the roller pair by making the paper feed cover enter into an opened state. However, in the case of making the subsidiary roller physically separated from the transport roller in order to draw the sheet, the user has to apply considerable pressure to the subsidiary roller. Therefore, in the case that the pressure of the transport roller is not suitably released, or in the case that the transport roller is not made run at idle, the user can not draw the sheet when the user does not pull the sheet with strong force. Consequently, there is a case that the important sheet is damaged. Furthermore, in the case of structure that the subsidiary roller is provided at a position at which the paper feed cover cannot be opened and closed when accessing the transport mechanism, the user can not release the pressure, which is applied to the transport roller, in the first place. 
     According to the art which is disclosed by PTLs 2 and 3, there is a case that, depending on a situation of the paper jam, it is impossible to transport the sheet to the paper discharge port by rotating the paper transport mechanism or the like. 
     The present invention has been conceived in order to solve the above-mentioned problem. A main object of the present invention is to provide a paper-sheet transport device which enables a user, when removing a sheet of paper from a transport mechanism, to easily remove the sheet of paper from the transport mechanism even with structure in which a transport roller is provided at a position inaccessible to a user. 
     Solution to Problem 
     To solve the above problem, an aspect of the present invention is: 
     a paper-sheet transport device, comprising: 
     a drive part that drives a transport mechanism transporting a sheet of paper; a cover; 
     a shaft that rotatable in a predetermined direction by drive generated by the drive part, the shaft including a transport roller fixed thereto for transporting the sheet of paper; 
     a lever that is arranged at, at least, a drive part side end out of both ends of the shaft and which, through a part of the cover, receives force due to an opening/closing operation of the cover; and 
     a ratchet via that the lever and the shaft are engaged or disengaged, and that changes from the engaged state to the disengaged state in response to the lever receiving the force due to the opening/closing operation of the cover. 
     Advantageous Effects of Invention 
     According to the present invention, when removing the sheet of paper from the transport mechanism, the user can easily remove the sheet of paper from the transport mechanism even with the structure in which the transport roller is provided at the position inaccessible to the user. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an external view of a paper-sheet transport device according to a first example embodiment of the present invention. 
         FIG. 2  is a diagram showing internal structure of the paper-sheet transport device according to the first example embodiment whose cover part is opened. 
         FIG. 3  is a diagram showing whole structure of a transport drive part according to the first example embodiment, and showing enlarged structure of a main part of the transport drive part. 
         FIG. 4A  is a diagram showing structure of an engagement part which engages the cover part and a paper-sheet transport part of the paper-sheet transport device according to the first example embodiment. 
         FIG. 4B  is a diagram showing structure of the engagement part which engages the cover part and the paper-sheet transport part of the paper-sheet transport device according to the first example embodiment. 
         FIG. 5A  is a diagram showing internal structure of a pressure change part of the paper-sheet transport device according to the first example embodiment. 
         FIG. 5B  is a diagram showing internal structure of the pressure change part of the paper-sheet transport device according to the first example embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Next, an example embodiment of the present invention will be explained in detail with reference to drawings. An identical or similar part in each drawing, which will be shown later, has an identical or similar reference sign. However, each drawing schematically shows structure in the example embodiment of the present invention and does not limit the present invention at all. That is, the example embodiment described in the following is an example of the present invention and can be appropriately changed within the scope which has the same essence. 
     First Example Embodiment 
       FIG. 1  is an external view (perspective view) of a paper-sheet transport device  100  according to a first example embodiment of the present invention.  FIG. 2  is a diagram showing internal structure of the paper-sheet transport device  100  according to the first example embodiment whose cover part  2  is opened. Structure, in which the paper-sheet transport device  100  according to the example embodiment is mounted on a printer, will be explained in the following as an example. That is, the present invention is not limited to the above-mentioned structure and is applicable to various devices which transport a sheet of paper. 
     The paper-sheet transport device  100  according to the first example embodiment includes a paper-sheet transport part  1  and the cover part  2  as shown in  FIG. 1 . 
     The paper-sheet transport part  1  is a mechanism which, when transporting various sheets (sheets of paper) to a print mechanism (not shown in the drawing), can transport each sheet of paper in a predetermined direction at a constant interval. Since the general art can be applied to the structure for transporting the sheet of paper, detailed explanation on the structure is omitted in the example embodiment. 
     The cover part  2  has a function to cover the paper-sheet transport part  1  as shown in  FIG. 1  and has open-able and closable structure so as to expose the most portion of the paper-sheet transport part  1  to the outside as shown in  FIG. 2 . It is assumed that, in order to realize the open-able and closable structure, the cover part  2  is fixed by a hinge (not shown in the drawing) or the like so as to be able to be rotated on a rotation axis, which is a part (a side) of plural surfaces forming an external shape, in order to make the paper-sheet transport part  1  enter into an exposed state from a covered state ( FIG. 1 ). That is, in a normal usage state, the cover part  2  is in a state that the cover part  2  is arranged above the paper-sheet transport part  1  so as to cover the paper-sheet transport part  1  as shown in  FIG. 1  (that is, state that the cover part  2  is closed (closed state)). In the case that it is necessary to draw a sheet from the paper-sheet transport part  1  because of, for example, an accident which is caused during a print processing, a user can open the cover part  2  upward as shown in  FIG. 2 . 
     Hereinafter, for the sake of convenience, it is assumed that the paper-sheet transport device  100  exists in the three-dimensional coordinate space (X-Y-Z coordinates) shown in  FIGS. 1 and 2  and the like, and then explanation will be continued under the assumption. 
       FIG. 3  is a diagram showing whole structure of a transport driving part  11  according to the first example embodiment and showing enlarged structure of a main part of the transport driving part  11  (lower-left of  FIG. 3 ). As shown in  FIGS. 2 and 3 , the paper-sheet transport part  1  includes the transport driving part  11  to transport the sheet in a transport direction. The transport driving part  11  includes a shaft  12  ( 12   a  and  12   b ) and a drive part  13 . 
     The drive part  13  includes a drive source, which generates drive force, such as a motor (not shown in the drawing) or the like, and a plurality of gears which are structured so as to rotate the shaft  12 . 
     The shaft  12  is provided along the Y axis in a direction parallel or almost parallel to the Y axis, and one end of the shaft  12  is fixed to the drive part  13 . In the present example embodiment, the shaft  12  includes the shaft  12   a  which is visible from the outside when the cover  2  is in the opened state (in  FIG. 2 , a window  1   a  through which the shaft  12   a  is visible is arranged within a protection cover), and the shaft  12   b  which is invisible and inaccessible to the user even in the state that the cover part  2  is opened. In the example embodiment, the shaft  12   a  and shaft  12   b  may be denoted collectively as the shaft  12  in some cases. 
     The shaft  12  includes a transport roller  12   e , which transports the sheet, at a predetermined position. The transport roller  12   e  is columnar or almost columnar roller which is made of the general material with elasticity such as the rubber or the like. The shaft  12  transmits drive (rotation) force, which is generated by the drive part  13 , to the transport roller  12   e . Thereby, the transport roller  12   e  is rotated in a predetermined direction, for example, in a state of forming a pair with a transport roller (not shown in the drawing) within the paper-sheet transport part  1 , and consequently transports the sheet, which is put on a transport path, in a predetermined direction. Hereinafter, the pair including the transport rollers  12   e  is denoted as “transport roller pair”. 
     A lower side of  FIG. 3  shows an enlarged view of a pressure change part  14 . As shown in the enlarged view, the shaft  12   b  partially includes a slender shaft  12   c  in a longitudinal direction of the shaft  12   b . The shaft  12   b  and the slender shaft  12   c  may have structure that a through-bore is arranged in the shaft  12   b  in the longitudinal direction of the shaft  12   b , and the slender shaft  12   c  penetrates the through-bore and is fixed by the press fit or the like. Or, the shaft  12   b  and the slender shaft  12   c  may have structure that a stopper hole (concave part), which has a shorter diameter than the shaft  12   b  has and which has a predetermined depth, is arranged in a section of the shaft  12   b , and the slender shaft  12   c  is fixed to the shaft  12   b  by carrying out the press-fit of a part of the slender shaft  12   c  into the stopper hole. Or, the above-mentioned structure of the shaft  12   b  and the slender shaft  12   c  may be realized through a lathe&#39;s cutting a circumference of a part of the shaft  12   b  in the longitudinal direction depending on the material of the shaft  12   b.    
     When the cover part  2  is in the closed state, the visible shaft  12   a  comes into contact with the transport roller  12   e . In this case, it is possible to apply pressure to the sheet, which comes into contact with the transport roller  12   e  arranged on the shaft  12   a , due to weight of the cover part  2  or the like. On the other hand, by making the cover part  2  enter into the opened state, the visible shaft  12   a  removes the weight of the cover part  2  or the like, and pressure is applied to the shaft  12   a  on manual so as to generate a gap between the transport roller  12   e  pair. Thereby, the pressure is removed from the sheet which comes into contact with the transport roller  12   e  arranged on the shaft  12   a.    
     The invisible shaft  12   b  includes a pressure change part  14  which is arranged at one end of the invisible shaft  12   b  on the drive part  13  side and which is shown in  FIG. 3  as an enlarged view of main part. 
     Each of  FIGS. 4A and 4B  is a diagram showing structure of an engagement part which engages the cover part  2  and the paper-sheet transport part  1  of the paper-sheet transport device  100  according to the first example embodiment. That is, each of  FIGS. 4A and 4B  shows structure in a cross section view taken along a dash-and-dot line A-A drawn in the enlarged view of main part (pressure change part  14 ) of  FIG. 3  (for the sake of convenience in explanation, each of  FIGS. 4A and 4B  includes a part which is not included by the A-A cross section view).  FIG. 5A  is a diagram showing internal structure of the main part (pressure change part  14 ), which is shown in the enlarged view of main part, at a time when the engagement part is in the state shown in  FIG. 4A , and  FIG. 5B  is a diagram showing internal structure of the main part (pressure change part  14 ), which is shown in the enlarged view of main part, at a time when the engagement part is in the state shown in  FIG. 4B   
     As shown in  FIG. 3 , the pressure change part  14  is arranged on a drive part  13  side end of the shaft  12   b . The pressure change part  14  includes a coil (coil spring)  15 , a fringe  16  and a lever  17  as a roughly classified component. 
     The coil  15  is a spring or the like which is wound in a shape of coil, and has predetermined elasticity. 
     The fringe  16  includes a fringe  16   a  arranged on a drive part  13  side (hereinafter, denoted as “first fringe”), and a fringe  16   b  on a side opposite to the drive part  13  (hereinafter, denoted as “second fringe”). The first fringe  16   a  and the second fringe  16   b  are arranged so that the coil  15  may be interposed between the first fringe  16   a  and the second fringe  16   b , and the slender shaft  12   c  of the shaft  12   b  penetrates a central part of the first fringe  16   a  and the second fringe  16   b.    
     The first fringe  16   a  is arranged on the drive part  13  side. The first fringe  16   a  is a brim part which comes into contact with one end of the coil  15 , and is pushed against the lever  17  by elastic force of the coil  15 , and whose diameter is longer than a diameter of the coil. 
     The second fringe  16   b  is a brim part which is fixed to the slender shaft  12   c  of the shaft  12   b , and is arranged at the other end of the coil  15 . A diameter of the second fringe  16   b  is longer than the diameter of the coil. 
     The lever  17  includes a ring part containing a shaft-bearing part  18  which one end of the slender shaft  12   c  penetrates, a pressure receive part  17   a  and a slope  17   b . The pressure receive part  17   a  receives force (stress) according to opening and closing the cover part  2 , and consequently can have a posture shown in  FIGS. 4A and 5A  and a posture shown in  FIGS. 4B and 5B . The slope  17   b  has an angle which can make insertion into the first fringe  16   a  smooth. A relation between the lever  17  and the cover part  2  will be explained in the following with reference to  FIG. 4A ,  FIG. 4B ,  FIG. 5A  and  FIG. 5B . 
     The cover part  2  in  FIG. 4A  and  FIG. 4B  is fixed by the hinge (not shown in the drawing) or the like so as to be able to be rotated on the rotation axis, which is a part (a side) of plural surfaces forming the external shape, in order to make the paper-sheet transport part  1  change from the covered state ( FIG. 1 ) to an exposed state.  FIG. 4A  shows fixation structure (hinge is not shown in the drawing) in which the paper-sheet transport part  1  and the cover part  2  are fixed each other in the closed state.  FIG. 4B  shows fixation structure (hinge is not shown in the drawing) in which the paper-sheet transport part  1  and the cover part  2  are fixed each other in the opened state. In addition to the above-mentioned fixation structure, a convex part  21  is arranged at, at least, one end (convex part  21  may be arranged at both ends) of one side, which is near to the lever  17  and is parallel or almost parallel to the Y axis, out of the plural surfaces, as shown in  FIG. 4A  and  FIG. 4B . When the cover part  2  is in the closed state, the convex part  21  projects in a negative direction of the Z axis. Moreover, the convex part  21  rotates clockwise according to a change of the cover  2  from the closed state to the opened state, and pushes the pressure receive part  17   a  of the lever  17  with sliding on the pressure receive part  17   a . Thereby, the lever  17  can have the posture shown in  FIGS. 4A and 5A  and the posture shown in  FIGS. 4B and 5B . 
     A shaft end  12   d  is arranged, for example, at both ends of the shaft  12   b  (or, slender shaft  12   c ), and includes a ratchet mechanism inside (detail will be mentioned later). The shaft end  12   d  is inserted into the shaft-bearing part (holder)  18  which is engaged with the lever  17 . The shaft-bearing part  18  has an elliptical hole (for example, an opening). In the state that the cover part  2  is closed, the shaft end  12   d  is arranged at a position which generates a space interval having a predetermined length d in the hole part in one direction (right direction in the case of  FIG. 4A ). 
     A longitudinal (Z axis direction) length of the elliptical hole of the shaft-bearing part  18  is designed to be slightly shorter than a diameter of the shaft end  12   d  and is designed so that the shaft end  12   d  does not project from the shaft-bearing part  18 . Here, the lever  17  does not come into contact with the convex part  21  of the cover part  2  in the case of the closed state ( FIG. 4A ). 
     On the other hand, in the state that the cover part  2  is opened ( FIG. 4B ), the shaft end  12   d  is arranged at a position which generates a space interval having the predetermined length d in the hole part in the other direction (left direction in the case of  FIG. 4B ). That is, according to the cover part  2  being opened, the convex part  21  of the cover part  2  comes into contact with the pressure receive part  17   a  of the lever  17  to gradually press the pressure receive part  17   a  as shown in  FIG. 4B . By carrying out the operation, the shaft-bearing part  18 , which is engaged with the lever  17 , slides (moves) in a direction almost equal to the X axis. As a result, in the state that the cover part  2  is completely opened, the space interval having the predetermined length d is generated at the left end of the shaft-bearing part  18 . 
     Next, a state change of the pressure change part  14  according to the change of the cover part  2  from the closed state to the opened state will be explained with reference to  FIGS. 5A and 5B . 
     The shaft end  12   d , which is inserted into the shaft-bearing part  18  engaged with the lever  17 , includes a ratchet  19 . The ratchet  19  includes a pawl  19   a  and a gear  19   b  which have shapes able to engage each other. Each of the pawl  19   a  and the gear  19   b , which are arranged oppositely and are engaged each other, has a shape (structure) that a plurality of vertical surfaces and a plurality of inclined surfaces are arranged alternately in a circumferential direction. In the engaged shape (structure), when rotating in a drive transmission direction which is a predetermined direction to transport the sheet, the vertical surfaces of the pawl  19   a  and the gear  19   b  come into contact each other in order to maintain the engaged state. On the other hand, when rotating in an opposite direction, the inclined surfaces of the pawl  19   a  and the gear  19   b  come into contact each other and slide so that the pawl  19   a  and the gear  19   b  may not be engaged each other. Then, the gear  19   b  climbs over the pawl  19   a  to run at idle. 
     As shown in  FIG. 5A , in the state that the cover part  2  is closed, the pawl  19   a  and the gear  19   b  are engaged and coupled each other, and a predetermined load is applied to the pawl  19   a  and the gear  19   b  by elastic force of the coil  15 . The elastic force is engagement force of the ratchet mechanism. 
     In the case that the cover part  2  is in the opened state, the pressure receive part  17   a  of the lever  17  is pressed by the convex part  21  of the cover part  2 , and the space interval having the predetermined length d is generated at a left end of the shaft-bearing part  18 . The length d is equal to a sliding distance d of the slope  17   b  of the lever  17  from a position of the slope  17   b  shown in  FIG. 5A  up to a position of the slope  17   b  shown in  FIG. 5B . As a result, as shown in  FIG. 5B , a predetermined interval e is generated between the pawl  19   a  and the gear  19   b  of the ratchet  19 . The engagement of the pawl  19   a  and the gear  19   b  is lost by the predetermined interval e, and the gear  19   b  climbs over the pawl  19   a  to run at idle. That is, in the case that the cover part  2  is in the closed state, the elastic force of the coil  15  is applied to rotation of the shaft  12   b , and in the case that the cover part  2  is in the opened state, repulsive force which is generated by the elastic force of the coil  15  applied to rotation of the shaft  12   b  is lost. 
     When the cover part  2  is opened and consequently the lever  17  is pushed by the convex part  21  to disengage the ratchet  19 , a relation of force magnitude at the time is that (force to maintain the opened state of the cover part  2 )&gt;(force to engage the ratchet). Therefore, when the cover part  2  is opened, even if an operator takes his hand off, the disengaged state of the ratchet  19  is maintained. Moreover, when the cover part  2  is closed, the lever  17  is pushed back by the engagement force of the ratchet  19 , and also the ratchet  19  returns to the engaged state. When the engagement force of the ratchet  19  does not strongly work on the force to push back the lever  17 , the lever  17  does not return. However, in the above-mentioned state, if drive transmission is generated by the drive part  13 , the drive transmission strongly works as the force to push back the lever  17  so as to supplement the engagement force of the ratchet. As a result, it is surely guaranteed that the lever  17  is returned at a time of the drive transmission. That is, the engagement force of the ratchet  19  is weaker than pressure with which the transport roller  12   e  transports the sheet. As a result, it is possible to draw the sheet from the paper-sheet transport part  1  with weak force, and it is possible to prevent the sheet from being damaged when the user draws the sheet. 
     Here, since the elastic force of the coil  15  may be not so strong in comparison with the pressure of the transport roller  12   e , force to draw the sheet in one direction (for example, direction to sheet discharge port) may be relatively weak even when the cover part  2  is in the closed state. 
     According to the first example embodiment mentioned above, when the user wants to remove the sheet (sheet of paper) from the transport mechanism since the paper jam is caused, the user can easily remove the sheet from the transport mechanism even with the structure in which the shaft  12   b  including the transport roller  12   e  is provided at the position inaccessible to the user. The reason is that, when removing the sheet, the lever  17 , which works cooperatively with the cover part  2 , disengages the ratchet  19  to make the shaft  12   a , to which the transport roller  12   e  is fixed, run at idle, and consequently it is possible to release the pressure with a light load. 
     The above-mentioned paper-sheet transport device  100  according to the first example embodiment can be grasped as the following explanation. 
     That is, the paper-sheet transport device  100  includes a drive part ( 11 ), a cover ( 2 ), a shaft ( 12   a ), a lever ( 17 ) and a ratchet ( 19 ). 
     The drive part ( 11 ) includes a transport mechanism for transporting the sheet of paper. 
     The cover ( 2 ) is fixed near to the drive part ( 11 ) so as to be able to be rotated. 
     The shaft ( 12   a ), to which a transport roller ( 12   e ) for transporting the sheet of paper that is a transport target is fixed, can be rotated in a predetermined direction by drive force of the drive part ( 11 ). 
     The lever ( 17 ) is arranged at, at least, a drive part ( 11 ) side end out of both ends of the shaft ( 12   a ), and receives force due to the opening/closing operation of the cover through a part of cover ( 2 ). 
     The ratchet ( 19 ) can engage and disengage the lever ( 17 ) and the shaft ( 12   a ). 
     In the paper-sheet transport device  100 , the ratchet ( 19 ) changes from the engaged state to the disengaged state in response to the lever ( 17 ) receiving the force due to the opening/closing operation of the cover ( 2 ), and consequently the transport roller ( 12   e ), which is fixed to the shaft ( 12   a ), enters into a state that the transport roller ( 12   e ) can rotate also in the direction opposite to the predetermined direction. 
     Thereby, when removing the sheet of paper from the transport mechanism, the user can easily remove the sheet of paper from the transport mechanism even with structure in which the transport roller is provided at the position inaccessible to the user. 
     Hereinbefore, the present invention has been explained with using the above-mentioned example embodiment as an exemplary example. However, the present invention is not limited to the above-mentioned example embodiment. That is, various aspects, which a person skilled in the art can understand, are applicable to the present invention within the scope of the present invention. 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2014-154774, filed on Jul. 30, 2014, the disclosure of which is incorporated herein in its entirety by reference. 
     REFERENCE SIGNS LIST 
     
         
           1  paper-sheet transport part 
           2  cover part 
           11  transport drive part 
           12  shaft 
           12   a  shaft 
           12   b  shaft 
           12   c  slender shaft part 
           12   d  shaft end 
           12   e  transport roller 
           13  drive part 
           14  pressure change part 
           15  coil 
           16  fringe 
           16   a  first fringe 
           16   b  second fringe 
           17  lever 
           17   a  pressure receive part 
           17   b  slope 
           18  shaft-bearing part 
           19  ratchet 
           19   a  pawl 
           19   b  gear 
           21  convex part