Abstract:
Disclosed is a paper folding apparatus for a binding machine, capable of discharging paper sheets by folding the paper sheets twice. The paper folding apparatus includes a first knife unit and a second knife unit. The first knife unit has a first feeding path and a pair of first paper folding rollers. The second knife unit has a second feeding path and a pair of second paper folding rollers. A paper arranging guide is installed in front of the pair of first paper folding rollers, and the second knife unit includes a pinion, a rack selectively engaged with the pinion, a rack guide configured to provide a path on which the rack is moved, a resilient member resiliently supporting the rack, and a second paper folding knife configured to move back and forth between the second paper folding rollers in association with a moving direction of the rack.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a paper folding apparatus for a binding machine. 
         [0003]    More particularly, the present invention relates to a paper folding apparatus for a binding machine adapted to discharge a paper sheet by folding twice the paper sheet fed from an image forming apparatus, such as a printer, to the binding machine. 
         [0004]    2. Description of the Related Art 
         [0005]    In general, image forming apparatuses, such as copy machines and printers, are equipped with various automatic sorting apparatuses for arranging and stacking paper sheets discharged from a paper discharging unit, and binding machines for stapling a discharged paper sheet after folding the discharged paper sheet or discharging the paper sheet in a folded state. 
         [0006]    A folding knife and a folding roller are generally necessary to fold a paper sheet using a paper folding apparatus of a binding machine. A knife driving apparatus and a folding roller are additionally necessary to fold a paper sheet twice or more, so the structure of the paper folding apparatus is complicated and the size of the paper folding apparatus is enlarged. 
         [0007]    Moreover, the manufacturing costs may increase due to the installation of the knife driving apparatus. 
       SUMMARY 
       [0008]    The present invention has been made to solve the problems occurring in the prior art, and an object of the present invention is to provide a paper folding apparatus for a binding machine which can be made in a small size and may have an improved paper folding function. 
         [0009]    It is another object of the present invention to provide a paper folding apparatus for a binding machine which can drive a secondary paper folding knife using a driving system that prevents a paper arranging guide from interfering with a primary paper folding operation, thereby improving the performance with a simple structure. 
         [0010]    It is a further object of the present invention to provide a paper folding apparatus for a binding machine which can fold a paper sheet twice at low manufacturing costs. 
         [0011]    In order to accomplish the above object, the present invention provides a paper folding apparatus for a binding machine. The paper folding apparatus includes a first knife unit including a first feeding path for feeding a paper sheet and a pair of first paper folding rollers installed on the first feeding path, the first knife unit being configured to push the paper sheet located on the first feeding path toward the pair of first paper folding rollers such that the paper sheet passes between the pair of first paper folding rollers in a primarily folded state; and a second knife unit including a second feeding path for feeding the primarily folded paper sheet and a pair of second paper folding rollers installed on the second feeding path, the first knife unit being configured to push the primarily folded paper sheet toward the pair of second paper folding rollers such that the primarily folded paper sheet passes between the pair of second paper folding rollers in a secondarily folded state. 
         [0012]    One of the pair of first paper folding rollers and one of the pair of second paper folding rollers are shared. 
         [0013]    The first knife unit includes a first paper folding knife configured to move back and forth between the pair of first paper folding rollers, and a drive unit configured to move the first paper folding knife back and forth. 
         [0014]    A paper arranging guide for guiding the paper sheet on the first feeding path is installed in front of the pair of first paper folding rollers and the paper arranging guide is moved before the first knife unit is driven so that the paper arranging guide does not interfere with the paper sheet being folded. 
         [0015]    The second knife unit includes a pinion configured to move in association with driving of the paper arranging guide, a rack selectively engaged with the pinion, a rack guide configured to provide a path on which the rack is moved, a resilient member configured to resiliently support the rack so that the rack is held in a home position, and a second paper folding knife configured to move back and forth between the second paper folding rollers in association with a moving direction of the rack. 
         [0016]    The pinion is rotatably fixed to both ends of a drive shaft of one of the pair of first paper folding rollers, and both ends of the paper arranging guide are fixed to the pinion eccentrically with a central axis of the pinion. 
         [0017]    The pinion and the paper arranging guide are reversibly rotatable independently from rotation of the pair of first paper folding rollers. 
         [0018]    The pinion has a fan-like shape. 
         [0019]    The resilient member is a tension spring. 
         [0020]    According to another aspect of the present invention, there is provided a paper folding apparatus for a binding machine, in which the paper folding apparatus includes a first knife unit including a first feeding path for feeding a paper sheet and a pair of first paper folding rollers installed on the first feeding path, the first knife unit being configured to push the paper sheet located on the first feeding path toward the pair of first paper folding rollers such that the paper sheet passes between the pair of first paper folding rollers in a primarily folded state; and a second knife unit including a second feeding path for feeding the primarily folded paper sheet and a pair of second paper folding rollers installed on the second feeding path, the first knife unit being configured to push the primarily folded paper sheet toward the pair of second paper folding rollers such that the primarily folded paper sheet passes between the pair of second paper folding rollers in a secondarily folded state. 
         [0021]    A paper arranging guide for guiding the paper sheet on the first feeding path is installed in front of the pair of first paper folding rollers, and the second knife unit includes a pinion configured to move in association with driving of the paper arranging guide, a rack selectively engaged with the pinion, a rack guide configured to provide a path on which the rack is moved, a resilient member configured to resiliently support the rack so that the rack is held in a home position, and a second paper folding knife configured to move back and forth between the second paper folding rollers in association with a moving direction of the rack. 
         [0022]    According to the paper folding apparatus for a binding machine of the present invention, the second knife unit  200  is driven by using a power system for moving the paper arranging guide  250  installed in front of the pair of first paper folding rollers  50  and configured to guide a paper sheet on the first feeding path  30  such that the paper arranging guide  250  may not interfere with the first paper folding operation, and one of the pair of first paper folding rollers  50  and one of the pair of second paper folding rollers  150  can be shared. Therefore, the performance of the paper folding apparatus for a binding machine can be improved with an inexpensive and simple structure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The above and other aspects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0024]      FIG. 1  is a perspective view illustrating a paper folding apparatus for a binding machine according to the present invention; 
           [0025]      FIG. 2  is an exploded perspective view of the paper folding apparatus for a binding machine according to the present invention when viewed from one side; 
           [0026]      FIG. 3  is an exploded perspective view of the paper folding apparatus for a binding machine according to the present invention when viewed from the other side; 
           [0027]      FIG. 4  is a side view illustrating the paper folding apparatus for a binding machine according to the present invention; and 
           [0028]      FIGS. 5A to 5G  are views for explaining the operation of the paper folding apparatus for a binding machine according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0029]    Hereinafter, the configuration and operation of a paper folding apparatus for a binding machine according to the present invention will be described in detail with reference to  FIGS. 2 to 4 . 
         [0030]    A paper support plate  60  of  FIG. 4  is omitted in  FIGS. 1 to 3  to avoid complexity, and a guide  106  and a drive motor  107  of  FIGS. 1 to 3  are also omitted in  FIG. 4  to avoid complexity. 
         [0031]    The paper folding apparatus  500  for a binding machine according to the present invention includes a first knife unit  100 , a second knife unit  200 , a pair of first paper folding rollers  50 , and a pair of second paper folding rollers  150 . 
         [0032]    The first knife unit  100  includes a support body  102  to which the first paper folding knife  101  is fixed, crank shafts  101  rotatably fixed to both ends of the support body  102 , gears configured to eccentrically fix the crank shafts  103 , and a rotary shaft  105  to which the gears  104  are fixed. The both ends of the support body  102  are coupled to guides  106  such that the support body  102  can linearly reciprocate as the crank shafts  103  are eccentrically driven during rotation of the gears  104 . The linear reciprocation of the support body  102  is achieved by a drive motor  107  engaged with one of the gears  105 . The first paper folding knife  101  is moved back and forth between the pair of paper folding rollers  50  while being guided by the guides  106  during driving of the drive motor  107 . 
         [0033]    The pair of first paper folding rollers  50  is installed at an intermediate portion of the first feeding path  30  along which the paper sheet is fed, and includes rollers  40  and  80 . The rollers  40  and  80  are fixed to drive shafts  40   a  and  80   a  respectively, and gears  40   b  and  80   b  are engaged with ends of the drive shafts  40   a  and  80   a . A plurality of additional gears are interposed between the gears  40   b  and  80   b  so that a rotational force of the drive motor  87  can be transferred to the additional gears. Although a rotational force of the drive motor  87  can be transferred to the gear  80   b  through the gear  40   b  dependently according to the present invention, a rotational force of the drive motor  87  may be transferred to the gear  40   b  through the gear  80   b  dependently. 
         [0034]    Meanwhile, a paper arranging guide  250  is installed in front of the pair of first paper folding rollers  50  to arrange or guide the paper sheet fed on the first feeding path  30 . The paper arranging guide  250  is spaced apart from the roller  40  in parallel to the roller  40 , and a ball bearing (not shown) is interposed between the paper arranging guide  250  and the roller  40  so that the paper arranging guide  250  is not moved in association with rotation of the roller  40 . The paper arranging guide  250  is fixed to an upper side of a fan-like pinion  201  rotatably supported by the drive shaft  40   a  so as to be eccentric to the central axis of the pinion, whereby the paper arranging guide  250  remains spaced apart from the roller  40  in parallel to the roller  40 . That is, the pinions  201  and the roller  40  are rotated about a common rotary shaft, i.e. the drive shaft  40   a , but are driven respectively by a drive motor  87  and a drive motor  207 . 
         [0035]    The pair of paper folding rollers  150  is installed at an intermediate portion of the first feeding path  130  along which the paper sheet is fed, and includes rollers  80  and  120 . The roller  120  is fixed to a drive shaft  120   a , and a gear  120   b  is fixed to one end of the drive shaft  120   a . The gear  120   b  is engaged with the gear  80   b.    
         [0036]    Thus, the roller  80  constituting both the first pair of paper folding rollers  50  and the pair of second paper folding rollers  150  is used in common, and the pair of first paper folding rollers  50  and the pair of second paper folding rollers  150  are simultaneously rotated to discharge a paper sheet only by transferring a driving force to any one of the three rollers. 
         [0037]    The second knife unit  200  is configured to push a paper sheet on the second feeding path  130  toward the pair of second paper folding rollers  150  and pass the paper sheet between the pair of second paper folding rollers  150  with the sheet being folded second. 
         [0038]    The second knife unit  200  includes racks  202 , rack guides  203  configured to guide linear movements of the racks  202 , a support body  205  fixed to the racks  202 , and a second paper folding knife  206  fixed to the support body  205 . The support body  205  to which the second paper folding knife  206  is fixed is fixed to a tension spring  204 , and the tension spring pull the support body  205  upward and resiliently support the support body  205  so that the support body  205  can always maintain at a home position when the racks  202  and the pinions  201  are not engaged with each other. That is, if the pinions  201  are rotated by the drive motor  207  and engaged with the racks  202 , it moves toward the downsides of the racks  202  to move the second paper folding knife  206  toward the pair of paper folding rollers  150 . The pinions  201  are reversely rotated by a predetermined angle using the drive motor  207  to move the racks  202  to the original positions. 
         [0039]    The operation of the paper folding apparatus  500  for a binding machine according to the present invention will be described in detail with reference to  FIGS. 5A to 5G . 
         [0040]    First, a paper sheet  90  is fed along the first feeding path  30  as in  FIG. 5A . 
         [0041]    The paper sheet  90  fed along the first feeding path  30  is guided by the paper support plate  60  and the paper arranging guide  250  and is discharged along the first feeding path  30  as it is when it is not folded. 
         [0042]    When the paper sheet is folded on the first feeding path  30 , the paper arranging guide  250  is moved so as not to interfere with the first paper folding operation as shown in  FIG. 5B  before driving of the first knife unit  100 . The movement of the paper arranging guide  250  is achieved by rotating the pinions  201  to which the paper arranging guide  250  by a predetermined angle using the drive motor  207 . 
         [0043]    If the paper arranging guide  250  is not moved during the first paper folding operation, a friction is caused between the paper sheet  90  and the paper arranging guide  50  when the paper sheet  90  is pushed between the pair of paper folding rollers  50  by driving the first knife unit  100 , causing a paper folding error. Thus, the paper arranging guide  250  is previously moved to avoid the paper folding error. 
         [0044]    If the paper arranging guide  250  is moved as in  FIG. 5B , the first paper folding knife  101  is pushed toward the pair of first paper folding rollers  50  by driving the first knife unit  100  as in  FIG. 5C  so that the paper sheet folded first can be discharged between the pair of paper folding rollers  50 . 
         [0045]    It is apparent that the pair of paper folding rollers  50  are controlled to be previously rotated by the drive motor  87  at the same time when or before the first knife unit  100  is driven, so that the fed paper sheet folded first can be discharged toward the second feeding path  130 . 
         [0046]    If the pair of paper folding rollers  50  are further driven in the state of  FIG. 5C , the paper  90  folded first is discharged along the second feeding path  130  as in  FIG. 5D . 
         [0047]    If there is no need to fold the paper sheet  90  second, the paper sheet  90  folded first may be discharged through the second feeding path  130  as it is. 
         [0048]    When it is necessary to fold the paper sheet  90  second, the second paper folding knife  206  is pushed toward the pair of second paper folding rollers  150  by driving the second knife unit  200  as in  FIG. 5E  after the paper sheet  90  folded first is fed to a certain position on the second feeding path  130 , and the paper sheet  90  to be folded second is pushed between the pair of second paper folding rollers  150 . 
         [0049]    The driving of the second knife unit  200  is achieved by rotating the pinions  201  by a predetermined angle using the drive motor  207  and lowering the second paper folding knife  206  toward the pair of second paper folding rollers  150  using the engagement of the pinions  201  and racks  202 . 
         [0050]    If the pair of second paper folding rollers  150  are further driven in the state of  FIG. 5E , the paper sheet  90  folded second is discharged to the outside between the pair of second paper folding rollers  150  as in  FIG. 5F . 
         [0051]    After the paper sheet  90  folded second is discharged between the pair of second paper folding rollers  150 , the drive motor  207  is reversely driven as in  FIG. 5G . Then, if the pinions  201  are reversely rotated by a predetermined angle, the engagement of the racks  202  and the pinions  201  is released and the support body  205  and the second paper folding knife  206  supported by the tension spring  204  are not lowered, but held in the home position. 
         [0052]    Although a paper folding apparatus for a binding machine according to an embodiment of the present invention has been described with reference to the accompanying drawings, the present invention is not limited by the illustration and description of the embodiment. 
         [0053]    Therefore, it will be understood to those skilled in the art that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.