Abstract:
An apparatus for transferring paper sheets includes a supply device which supplies sheets, a supply unit which is provided as part of the supply device and forms a supply outlet through which the sheets are ejected, a receiving device which is connected to the supply device in such a manner as to be vertically movable relative to the supply device, and a receiving unit which is provided as part of the receiving device and forms a receiving inlet by which the sheets are received, wherein one of the supply unit and the receiving unit is configured to be vertically movable, and changes a vertical position thereof in response to relative positional relationship between the supply device and the receiving device.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention generally relates to paper sheet transfer apparatus, and particularly relates to a paper sheet transfer apparatus comprised of a paper sheet supplying apparatus and a paper sheet receiving apparatus implemented as part of a copier machine or the like.  
           [0003]    2. Description of the Related Art  
           [0004]    Image forming apparatus such as a printer, a copier, or a facsimile machine is generally provided with options to install peripheral units such as a large-scale paper supply apparatus that stores therein a large number of print sheets, or a post-processing apparatus such as a punch, a mailbox, a paper folding unit, a sorter for sorting printed sheets, etc. Such optional apparatuses are detachable from the image forming apparatus. When an optional apparatus is attached, the positioning thereof relative to the image forming apparatus needs to be carefully made such that sheets are supplied from the paper supply apparatus to the image forming apparatus without paper jam, or are supplied from the image forming apparatus to the post-processing apparatus without paper jam.  
           [0005]    [0005]FIG. 10 is a drawing showing a paper supply and receipt mechanism of the related art. FIG. 10 shows the configuration of a paper exchanging portion between an image forming apparatus and a large-scale paper supply apparatus. In FIG. 10, upper and lower guide plates  136  and  137  of the paper supply apparatus on the paper supply side are fixed as to their positions, and so are the upper and lower guide plates  36  and  37  of the image forming apparatus on the paper receipt side. In order to insure proper paper feeding even if relative positioning in the vertical direction exhibits displacement for one reason or another, the upper and lower guide plates  36  and  37  of the image forming apparatus are configured to exhibit a large aperture angle. This aperture angle may be too wide in some instances, causing a failure to pass a paper sheet in the case of a curled sheet, thereby causing paper jam.  
           [0006]    To obviate this problem, some optional apparatuses are designed to be adjustable as to their positions relative to the image forming apparatus, thereby making it possible to cope with various restrictions imposed regarding the place of installment. Japanese Patent Laid-open Application No. 11-79430 discloses such an optical apparatus. This optional apparatus is a large-scale paper supply apparatus, which includes a paper supply unit and a paper sheet rack that supports the paper supply unit in a position adjustable manner.  
           [0007]    In this related-art configuration, the paper supply unit and the paper sheet rack are provided as separate units. Because of this, the paper supply unit needs to be installed by attaching it to the image forming apparatus, and, then, the paper sheet rack has to be installed by attaching it to the paper supply unit. This requires several steps of installation process, and is thus cumbersome. Further, separate housings are necessary for the paper supply unit and the paper sheet rack, respectively, resulting in a cost increase of the large-scale paper supply apparatus.  
           [0008]    Accordingly, there is a need for a paper sheet transfer apparatus which can be readily installed and can be taken care of through simple maintenance work while providing proper paper transfer performance.  
         SUMMARY OF THE INVENTION  
         [0009]    It is a general object of the present invention to provide a sheet transfer apparatus that substantially obviates one or more of the problems caused by the limitations and disadvantages of the related art.  
           [0010]    Features and advantages of the present invention will be set forth in the description which follows, and in part will become apparent from the description and the accompanying drawings, or may be learned by practice of the invention according to the teachings provided in the description. Objects as well as other features and advantages of the present invention will be realized and attained by a sheet transfer apparatus particularly pointed out in the specification in such full, clear, concise, and exact terms as to enable a person having ordinary skill in the art to practice the invention.  
           [0011]    To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, an apparatus for transferring paper sheets according to the present invention includes a supply device which supplies sheets, a supply unit which is provided as part of the supply device and forms a supply outlet through which the sheets are ejected, a receiving device which is connected to the supply device in such a manner as to be vertically movable relative to the supply device, and a receiving unit which is provided as part of the receiving device and forms a receiving inlet by which the sheets are received, wherein one of the supply unit and the receiving unit is configured to be vertically movable, and changes a vertical position thereof in response to relative positional relationship between the supply device and the receiving device.  
           [0012]    In the apparatus described above, the receiving unit on the sheet receiving side and the supply unit on the sheet supply side are configured to be vertically movable, and shift their positions in response to relative positional relationship between the supply device and the receiving device. Even if the supply device is positioned lower than or higher than the receiving device, or is relatively displaced in a vertical direction over a prolonged period of time, proper sheet transfer can be achieved. In order to make the supply unit or the receiving unit vertically movable, they may be configured to swing around a pivot point, or may be configured to be elastically bendable in the vertical direction.  
           [0013]    With this provision, it suffices that the supply device and the receiving device be fixed with respect to their horizontal positions, and these two devices can be connected in such a manner that allows for vertical movement. This makes it easier to install the devices and attend to maintenance work while keeping sufficiently proper performance of sheet transfer.  
           [0014]    Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a sectional view showing a schematic configuration of an image forming apparatus provided with a large-scale paper supply apparatus and a finisher;  
         [0016]    [0016]FIG. 2 is an illustrative drawing showing portions where the image forming apparatus and the large-scale paper supply apparatus are connected together;  
         [0017]    [0017]FIG. 3 is a schematic side view for explaining a paper transfer mechanism between the image forming apparatus and the large-scale paper supply apparatus according to a first embodiment of the present invention;  
         [0018]    [0018]FIG. 4 is an illustrative drawing showing the paper transfer mechanism of FIG. 3;  
         [0019]    [0019]FIGS. 5A and 5B are illustrative drawings for explaining the function of a stopper formed as part of an upper guide plate;  
         [0020]    [0020]FIG. 6 is an illustrative drawing showing the configuration of guide plates of the image forming apparatus and the large-scale paper supply apparatus according to a second embodiment of the present invention;  
         [0021]    [0021]FIG. 7 is an illustrative drawing showing the configuration of guide plates of the image forming apparatus and the large-scale paper supply apparatus according to a third embodiment of the present invention;  
         [0022]    [0022]FIG. 8 is an illustrative drawing showing the configuration of guide plates of the image forming apparatus and the large-scale paper supply apparatus according to a fourth embodiment of the present invention;  
         [0023]    [0023]FIGS. 9A and 9B are illustrative drawings showing the configuration of guide plates of the image forming apparatus and the large-scale paper supply apparatus according to a fifth embodiment of the present invention; and  
         [0024]    [0024]FIG. 10 is a drawing showing a paper supply and receipt mechanism of the related art. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    In the following, embodiments of the present invention will be described with reference to the accompanying drawings.  
         [0026]    [0026]FIG. 1 is a sectional view showing a schematic configuration of an image forming apparatus provided with a large-scale paper supply apparatus and a finisher. FIG. 2 is an illustrative drawing showing portions where the image forming apparatus and the large-scale paper supply apparatus are connected together. FIG. 3 is a schematic side view for explaining a paper transfer mechanism between the image forming apparatus and the large-scale paper supply apparatus according to a first embodiment of the present invention. FIG. 4 is an illustrative drawing showing the paper transfer mechanism of FIG. 3.  
         [0027]    As shown in FIG. 1, an image forming apparatus  100  is provided with optional units that are a large-scale paper supply apparatus  107  and a finisher  3 . The present invention is directed to a paper transfer apparatus that transfers paper between an image forming apparatus and an optional unit, and is applicable to a unit for receiving printed sheets from the image forming apparatus as well as a unit for supplying paper sheets to the image forming apparatus. In this example of FIG. 1, a description will be given with regard to the paper transfer mechanism between the large-scale paper supply apparatus  107  and the image forming apparatus  100 .  
         [0028]    As shown in FIG. 1, the image forming apparatus  100  has a document reader  110  at the top that includes a double-sided document feeding means and a document reading means for performing optical reading of documents. Under the document reader  110 , an image forming unit is provided that includes a photosensitive drum  101 , an electric charger  102 , an exposure unit  103 , a conveyor belt  104 , a drum cleaning unit  105 , and a development unit  106 . A paper sheet on which an image is formed by the image forming unit is subjected to fixing process by a fixing unit  108 , and is then supplied by a path selecting nail  116  to the finisher  3  through ejection rollers  1  or to a paper sheet returning unit  109  used for printing on both sides of a paper sheet. Under the paper sheet returning unit  109 , a paper sheet supply unit comprised of four sheet supply trays  113 . Paper sheets P stored in the sheet supply trays  113  are transferred to the image forming unit through transfer rollers  111  and resist rollers  112 . The image forming apparatus  100  is provided with casters  115  that support all the weight thereof.  
         [0029]    The finisher  3  includes a punch unit  4  for making holes through the paper sheets P supplied through the ejection rollers  1  and a staple unit  7  for stapling the paper sheets P supplied to a stable tray  8 . The paper sheets P that are not undergoing stapling are ejected onto an ejection tray  5  situated at the top after being guided thereto by a path selection nail  9 . When stapling is necessary, the paper sheets P are supplied to the staple tray  8  by the path selection hooks  9  and  10 , and are stabled by the staple unit  7 , followed by being ejected onto a paper stack tray  6 .  
         [0030]    The large-scale paper supply apparatus  107  stores therein a large number of paper sheets P as a stack of paper sheets, and includes a sheet supply tray  113   a , which has a vertical position thereof adjustable by a powered adjustment mechanism. Paper sheets P supplied from the sheet supply tray  113   a  are ejected from the large-scale paper supply apparatus  107  through ejection rollers  111 , and are fed into the image forming apparatus  100  through a paper-sheet inlet. The large-scale paper supply apparatus  107  are provided with casters  125  that support all the weight thereof.  
         [0031]    Relative positioning between the image forming apparatus  100  and the large-scale paper supply apparatus  107  is made by engaging pins  120   a  and  120   b  of the image forming apparatus  100  in the vertically elongated holes  121   a  and  121   b  of the large-scale paper supply apparatus  107  as shown in FIG. 2. The pins  120   a  and  102   b  project horizontally from the side panel of the image forming apparatus  100 , and the elongated holes  121   a  and  121   b  are formed on the side panel of the large-scale paper supply apparatus  107 . With this configuration, horizontal positioning is fixed, while vertical positioning is not fixed in FIG. 1. This makes it easier to attach/detach the large-scale paper supply apparatus  107  to/from the image forming apparatus  100 .  
         [0032]    In the first embodiment of the present invention, as shown in FIG. 3 and FIG. 4, an upper guide plate  26  of the image forming apparatus  100  is configured to swing around a pivot point  26   b  whereas upper and lower guide plates  126  and  127  of the large-scale paper supply apparatus  107  are provided as fixed members. The upper guide plate  126  is provided with a positioning rod  126   a , and the upper guide plate  26  of the image forming apparatus  100  has a positioning guide  26   a  that receives the positioning rod  126   a . Further, the upper guide plate  26  has a stopper  26   c  extending downward and formed as an integral part thereof, which comes in contact with the lower guide plate  27 . The stopper  26   c  serves to prevent the upper guide plate  26  from dropping exceedingly when the image forming apparatus  100  stands alone.  
         [0033]    In this embodiment as described above, the upper guide plate  26  of the image forming apparatus  100  on the sheet receiving side is configured to swing freely. This design takes into account weight difference between the image forming apparatus  100  and the large-scale paper supply apparatus  107 . If the floor surface is soft in the place where the image forming apparatus  100  is installed, the image forming apparatus  100  heavier than large-scale paper supply apparatus  107  may sink deeper after an extended period of time. In such a case, the upper and lower guide plates  26  and  27  of the image forming apparatus  100  are displaced downward. In the related-art configuration of FIG. 10, the upper guide plate  36  of the image forming apparatus  100  would not provide a sufficient sheet transfer angle. In this embodiment, however, the upper guide plate  26  of the image forming apparatus  100  swings about the pivot point  26   b  as shown in FIG. 3 and FIG. 4, and the positioning rod  126   a  of the upper guide plate  126  fixed to the large-scale paper supply apparatus  107  is pressed against the positioning guide  26   a  of the upper guide plate  26  of the image forming apparatus  100 . Through this pressing movement, the upper guide plate  26  swings so as to provide a sufficient sheet transfer angle on the side of the image forming apparatus  100 .  
         [0034]    [0034]FIGS. 5A and 5B are illustrative drawings for explaining the function of the stopper  26   c  formed as part of the upper guide plate  26 . FIG. 5A shows the way the guide plates are positioned when the large-scale paper supply apparatus is attached to the image forming apparatus, and FIG. 5B shows the way the guide plates are positioned when the large-scale paper supply apparatus is detached from the image forming apparatus. As shown in FIG. 5A, when the image forming apparatus  100  stands alone before the large-scale paper supply apparatus  107  is attached to the image forming apparatus  100 , the upper guide plate  26  of the image forming apparatus  100  is supported by the lower guide plate  27  as the stopper  26   c  is pressed against it. When the large-scale paper supply apparatus  107  is brought closer as shown by an arrow A, the positioning rod  126   a  of the upper guide plate  126  fixed to the large-scale paper supply apparatus  107  comes in contact with and then slides on the positioning guide  26   a  of the upper guide plate  26  of the image forming apparatus  100 . As a result, the upper guide plate  26  of the image forming apparatus  100  swings in the direction indicated by an arrow D in FIG. 5B, and comes to a halt. When this happens, the image forming apparatus  100  and the large-scale paper supply apparatus  107  are fixed with each other through connecting means (not shown).  
         [0035]    When the image forming apparatus  100  is detached from the large-scale paper supply apparatus  107 , the connecting means is disengaged, and the large-scale paper supply apparatus  107  is moved away in the direction shown by an arrow B in FIG. 5B. In conjunction with this movement, the positioning rod  126   a  of the upper guide plate  126  fixed to the large-scale paper supply apparatus  107  is detached from the positioning guide  26   a  of the upper guide plate  26  of the image forming apparatus  100  after sliding thereon. This results in the stopper  26   c  of the upper guide plate  26  coming into contact with the lower guide plate  27  fixed in the image forming apparatus  100 .  
         [0036]    The embodiment described above has been described by referring to an example in which paper sheets are transferred between the image forming apparatus  100  and the large-scale paper supply apparatus  107 . It should be noted that the same configuration as described above may be used for sheet transfer between the image forming apparatus  100  and the finisher  3 .  
         [0037]    [0037]FIG. 6 is an illustrative drawing showing the configuration of guide plates of the image forming apparatus and the large-scale paper supply apparatus according to a second embodiment of the present invention.  
         [0038]    In the second embodiment of the present invention, as shown in FIG. 6, a lower guide plate  227  of the image forming apparatus  100  is configured to swing around a pivot point  227   b  whereas upper and lower guide plates  326  and  327  of the large-scale paper supply apparatus  107  are provided as fixed members. The lower guide plate  327  is provided with a positioning rod  327   a , and the lower guide plate  227  of the image forming apparatus  100  has a positioning guide  227   a  that receives the positioning rod  327   a . The lower guide plate  227  has a hooking part  227   d , to which a coil spring  231  is hooked at one end thereof. The other end of the coil spring is fixed to a spring fixing part  230  that is situated at a predetermined position inside the image forming apparatus  100 . The coil spring  231  serves to pull up the lower guide plate  227  at all times, thereby preventing the lower guide plate  227  from dropping from its own weight. The lower guide plate  227  has a stopper  227   c  extending upward and formed as an integral part thereof, which comes in contact with the upper guide plate  226 . The stopper  227   c  serves to prevent the lower guide plate  227  from being lifted exceedingly when the image forming apparatus  100  stands alone.  
         [0039]    In this embodiment as described above, the lower guide plate  227  of the image forming apparatus  100  on the sheet receiving side is configured to swing freely. With this provision, even if the large-scale paper supply apparatus  107  sinks lower than the image. forming apparatus  100 , proper sheet transfer can be achieved from the large-scale paper supply apparatus  107  to the image forming apparatus  100 .  
         [0040]    [0040]FIG. 7 is an illustrative drawing showing the configuration of guide plates of the image forming apparatus and the large-scale paper supply apparatus according to a third embodiment of the present invention.  
         [0041]    In the third embodiment of the present invention, as shown in FIG. 7, an upper guide plate  426  of the image forming apparatus  100  is configured to swing around a pivot point  426   b , and a lower guide plate  427  is also configured to swing around a pivot point  427   b . In the large-scale paper supply apparatus  107 , an upper guide plate  526  is secured in a fixed position and provided with a positioning rod  526   a , and a lower guide plate  527  is secured in a fixed position and provided with a positioning rod  527   a . In the image forming apparatus  100 , the upper guide plate  426  has a positioning guide  426   a  that receives the positioning rod  526   a , and the lower guide plate  427  has a positioning guide  427   a  that receives the positioning rod  527   a . The lower guide plate  427  has a hooking part  427   d , to which a coil spring  431  is hooked at one end thereof. The other end of the coil spring  431  is fixed to a spring fixing part  430  that is situated at a predetermined position inside the image forming apparatus  100 . The coil spring  431  serves to pull up the lower guide plate  427  at all times, thereby preventing the lower guide plate  427  from dropping from its own weight.  
         [0042]    The upper guide plate  426  has a stopper  426   c  extending downward and formed as an integral part thereof, which comes in contact with an opposite stopper  442  fixedly provided at a predetermined location inside the image forming apparatus  100 . The stopper  426   c  serves to prevent the upper guide plate  426  from dropping exceedingly when the image forming apparatus  100  stands alone. By the same token, the lower guide plate  427  has a stopper  427   c  extending upward and formed as an integral part thereof, which comes in contact with an opposite stopper  441  fixedly provided at a predetermined location inside the image forming apparatus  100 . The stopper  427   c  serves to prevent the lower guide plate  427  from being lifted exceedingly when the image forming apparatus  100  stands alone.  
         [0043]    In this embodiment as described above, the upper and lower guide plates  426  and  427  of the image forming apparatus  100  on the sheet receiving side are configured to swing freely. With this provision, even if the large-scale paper supply apparatus  107  is displaced lower than or higher than the image forming apparatus  100 , proper sheet transfer can be achieved from the large-scale paper supply apparatus  107  to the image forming apparatus  100 .  
         [0044]    [0044]FIG. 8 is an illustrative drawing showing the configuration of guide plates of the image forming apparatus and the large-scale paper supply apparatus according to a fourth embodiment of the present invention.  
         [0045]    In the fourth embodiment of the present invention, as shown in FIG. 8, upper and lower guide plates  626  and  627  of the image forming apparatus  100  are fixed whereas upper and lower guide plates  726  and  727  of the large-scale paper supply apparatus  107  are configured to swing about a pivot point  730 . The upper and lower guide plates  726  and  727  are connected together by a connecting member  731  so that a space between the guide plates does not vary with swinging movement. The lower guide plate  727  has a positioning rod  727   a  formed thereon. In the image forming apparatus  100 , the fixed lower guide plate  627  has a positioning guide  627   a  formed thereon for the purpose of receiving the positioning rod  727   a.    
         [0046]    In this embodiment, the upper and lower guide plates  726  and  727  of the large-scale paper supply apparatus  107  on the paper supply side are connected together through the connecting member  731  and configured to swing around the pivot point  730 , so that the upper and lower guide plates  726  and  727  swing together as one coherent unit without causing a change in the gap space between the guide plates, thereby shifting the position of sheet ejection in a vertical direction. With this provision, even if the large-scale paper supply apparatus  107  is displaced lower than or higher than the image forming apparatus  100 , proper sheet transfer can be achieved from the large-scale paper supply apparatus  107  to the image forming apparatus  100 .  
         [0047]    [0047]FIGS. 9A and 9B are illustrative drawings showing the configuration of guide plates of the image forming apparatus and the large-scale paper supply apparatus according to a fifth embodiment of the present invention.  
         [0048]    In the fifth embodiment of the present invention, as shown in FIG. 9A, upper and lower guide plates  826  and  827  of the image forming apparatus  100  are fixedly mounted, and upper and lower guide plates  926  and  927  of the large-scale paper supply apparatus  107  are also fixedly mounted. The upper and lower guide plates  826  and  827  of the image forming apparatus  100  are made of elastic material, and can change their shapes elastically in response to a stress applied thereto. On the other hand, the upper and lower guide plates  926  and  927  of the large-scale paper supply apparatus  107  are not elastic. With this provision, if the large-scale paper supply apparatus  107  is displaced upward relative to the image forming apparatus  100 , the upper guide plate  826  of the image forming apparatus  100  is elastically bent as shown in FIG. 9B, thereby providing a sufficient paper transfer angle. By the same token, if the large-scale paper supply apparatus  107  is displaced downward relative to the image forming apparatus  100 , the lower guide plate  827  of the image forming apparatus  100  is elastically bent, thereby providing a sufficient paper transfer angle.  
         [0049]    The above description was provided with respect to a case in which the guide plates of the image forming apparatus  100  are elastically bendable. Alternatively, the upper and lower guide plates of the large-scale paper supply apparatus  107  may be configured in such a manner as to be elastically bendable without changing the gap space between the guide plates.  
         [0050]    Further, the present invention is not limited to these embodiments, but various variations and modifications may be made without departing from the scope of the present invention.  
         [0051]    The present application is based on Japanese priority applications No. 2001-117343 filed on Apr. 16, 2001 and No. 2002-097467 filed on Mar. 29, 2002, with the Japanese Patent Office, the entire contents of which are hereby incorporated by reference.