Patent Publication Number: US-7901176-B2

Title: Sheet supply/convey supporting device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to and incorporates by reference the entire contents of Japanese priority document 2007-196033 filed in Japan on Jul. 27, 2007. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sheet supply/convey supporting device. 
     2. Description of the Related Art 
     When sheets are supplied to an image forming apparatus such as a copier, a printer, and a facsimile, a carriage is used to convey the sheets from a sheet storing area to the image forming apparatus. However, currently, a user (an operator) has to supply the sheets by hand from the carriage to a cassette or a tray of the image forming apparatus. 
     The act of supplying sheets places a burden on the user because the user bends his/her knees or bows to supply the sheets to the cassette or the tray, so that it is a hard work for, particularly, women or elderly people. Furthermore, the larger and larger number of sheets is recently supplied to a high-speed image forming apparatus and the act of supplying the sheets increases in frequency. Consequently, the user has been more burdened with supplying sheets. 
     Therefore, various apparatuses and methods to reduce such a burden of supplying sheets to an image forming apparatus or a printing machine have been proposed. 
     Japanese Patent Application Laid-open No. 2002-240996 discloses a roll-sheet-supply supporting device that includes a roll-sheet holding mechanism for holding a roll of sheet, an up-and-down mechanism for moving the roll-sheet holding mechanism up and down, and a conveying mechanism for conveying the roll-sheet holding mechanism and the up-and-down mechanism. 
     Japanese Patent Application Laid-open No. S61-12538 discloses a sheet loading method. According to the method, a sheet loading plate is placed on crossbars attached to a carriage, a stack of sheets is placed on the sheet loading plate, the carriage is moved to a feeding unit of a printing machine, the sheet loading plate on which the sheets are stacked is lifted by an elevating bar of the printing machine, and the sheets are positioned to a predetermined position for sheets to be supplied. 
     However, the roll-sheet-supply supporting device disclosed in Japanese Patent Application Laid-open No. 2002-240996 serves to assist supplying a roll of sheet and does not serve to supply sheets to a common image forming apparatus in which cut sheets, that is, a stack of sheets is used. The sheet loading method disclosed in Japanese Patent Application Laid-open No. S61-12538 requires a dedicated configuration on a side of an image forming apparatus such as an elevating bar and cannot be supported by a general apparatus. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to at least partially solve the problems in the conventional technology. 
     According to an aspect of the present invention, there is provided a sheet supply/convey supporting device used for supplying a sheet stack to a sheet accommodating unit, the sheet supply/convey supporting device including a sheet placing unit that includes a pair of guide members and a supporting plate and that includes a space for holding a sheet stack, the guide members defining both sides of the space, and the supporting plate defining a bottom of the space to support the sheet stack and being movable between an opened position at which the bottom is opened and a closed position at which the bottom is closed; and a carriage member that supports the sheet placing unit and includes a driving mechanism for lifting or lowering the sheet placing unit. 
     The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a sheet supply/convey supporting device as an example according to an embodiment of the present invention; 
         FIGS. 2A ,  2 B, and  2 C are a front view, a side view, and a rear view of the sheet supply/convey supporting device, respectively; 
         FIG. 3  is a perspective view of a sheet placing unit shown in  FIG. 1 ; 
         FIG. 4  is a perspective view for explaining a state in which a supporting plate shown in  FIG. 1  is moved; 
         FIGS. 5A and 5B  are perspective views partially illustrating a guiding plate and the supporting plate shown in  FIG. 1 , respectively; 
         FIG. 6  is a schematic diagram of a driving mechanism of the supporting plate; 
         FIGS. 7A and 7B  are schematic diagrams of a curved portion of coupling guides shown in  FIG. 3 ; 
         FIG. 8  is a schematic diagram for explaining a state in which a distance between a pair of guiding plates is adjusted; 
         FIG. 9  is a schematic diagram for explaining a state in which sheets are placed on the sheet placing unit; 
         FIG. 10  is a perspective view for explaining a sheet supplying operation; 
         FIG. 11  is a perspective view for explaining a carriage positioning operation; 
         FIG. 12  is a schematic diagram for explaining a state in which the supporting plate is moved to supply sheets; 
         FIG. 13  is a perspective view for explaining a state in which the sheet placing unit is lifted after sheets are supplied; 
         FIG. 14  is a perspective view for explaining a case in which printed material on which an image is formed is conveyed; and 
         FIG. 15  is a perspective view for explaining a state in which printed material is moved from a discharging tray to the sheet placing unit. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Exemplary embodiments of the present invention are explained in detail below with reference to the accompanying drawings. 
       FIG. 1  is a perspective view of a sheet supply/convey supporting device  1  that includes a carriage  10  and a sheet placing unit  20  as an example according to an embodiment of the present invention.  FIGS. 2A to 2C  are a front view, a side view, and a rear view of the sheet supply/convey supporting device  1 , respectively. 
     The carriage  10  includes a mainframe  11 . The mainframe  11  includes longitudinal beams  11   a  and lateral beams  11   b , and has an L-shape when viewed from the side. A driving unit  12  is arranged between the longitudinal beams  11   a . A handle  13  is attached to a rear surface of each of the longitudinal beams  11   a . Two casters  15  are attached below each of the lateral beams  11   b . A battery  18  is arranged at a joint of the longitudinal beams  11   a  and the lateral beams  11   b . A guide bar (a positioning unit)  14  that has an L-shape when viewed from the front side is attached to one side of the joint to project from an outer surface of the mainframe  11 . 
     The sheet placing unit  20  includes a pair of right and left guiding plates  21  (guiding members) arranged opposed to each other, and a sheet holding space  26  is formed between the guiding plates  21 . Each of the guiding plates  21  is attached to and supported by the driving unit  12  of the carriage  10  through supporting arms  24 . The sheet placing unit  20  is supported above the lateral beams  11   b  in front of the longitudinal beams  11   a  and can be lifted or lowered along the longitudinal beams  11   a . Supporting-plate holding units  22  are provided to the guiding plates  21  to form a holding space in which a bendable supporting plate  23  is contained and held in a slidably movable manner along outer surfaces (side surfaces and a bottom surface) of the guiding plates  21 . As shown in  FIGS. 3 and 4 , the guiding plates  21  are arranged with a space therebetween and are coupled by coupling guides (guide rails)  25  arranged on the front and back sides between the guiding plates  21 . The coupling guide  25  on the back side (on the side of the longitudinal beam  11   a ) is not shown in  FIGS. 3 and 4 . 
     As described above, the supporting plate  23  can slidably move inside the holding space formed by the supporting-plate holding units  22  and the guiding plates  21 . As shown in  FIGS. 2A and 3 , when the supporting plate  23  is arranged over the right and left guiding plates  21 , the supporting plate  23  covers a bottom of the sheet holding space  26  between the guiding plates  21 , so that sheets P can be placed in the sheet holding space  26 . As shown in  FIG. 4 , when one end of the supporting plate  23  on the side of one guiding plate  21  is held and pulled up in a direction indicated by an arrow and the other end of the supporting plate  23  comes off the other guiding plate  21 , the bottom of the sheet holding space  26  is opened. As the supporting plate  23  is pulled up, the opening is gradually increased. When the other end of the supporting plate  23  is accommodated in the one guiding plate  21 , an area surrounded by the guiding plates  21  and the coupling guides  25 , that is, the bottom of the sheet holding space  26  is fully opened. When fully opening the bottom of the sheet holding space  26 , it is not necessary to pull up the whole supporting plate  23  from the one guiding plate  21 . Furthermore, the supporting plate  23  can be pulled up from any one of the guiding plates  21  to open the bottom of the sheet holding space  26 . As shown in  FIGS. 3 and 4 , a plurality of ribs  21   a  is provided to inner surfaces of the guiding plates  21 , each of which extends in an up-and-down direction. 
       FIGS. 5A and 5B  are perspective views partially illustrating the guiding plate  21  and the supporting plate  23 , in which only the supporting plate  23  is partially illustrated in  FIG. 5B . The supporting plate  23  is made of, for example, polycarbonate-acrylonitrile butadiene styrene (PC-ABS (PC/ABS)) resin. As shown in  FIG. 5B , a plurality of grooves  23   a  is formed in the supporting plate  23  in a lateral direction, so that the supporting plate  23  can be bent. In the embodiment, the supporting plate  23  is manually moved by a user. However, as shown in  FIG. 6 , the supporting plate  23  can be moved by a driving unit, which results in improved workability. 
     Specifically, as shown in  FIG. 6 , racks  27  are integrally formed on both sides of the supporting plate  23 . A driving unit  30  is attached to one of the guiding plates  21  positioned on the back side. The driving unit  30  includes a motor  31  serving as a driving source, a gear train  32 , two rollers  33  with gears, and a control unit (not shown). The rollers  33  are rotatably held by the supporting-plate holding unit  22  (see,  FIGS. 1 and 2 ) to engage with the racks  27 . This configuration enables the supporting plate  23  to be lifted or lowered through the motor  31 , thereby opening or closing the bottom of the sheet holding space  26 . 66-nylon resin is used for the supporting plate  23  to slide the supporting plate  23  easily. Thus, it is easy to move the supporting plate  23  irrespective of the weight of stacked sheets. 
     As shown in  FIGS. 7A and 7B , each coupling guide  25  is provided with a curved portion  25   a  near one of the guiding plates  21 . Therefore, when the supporting plate  23  is pulled in along one of the guiding plates  21 , the supporting plate  23  is curved like a bow, which prevents a sheet from being pulled (involved) into the guiding plate  21 . 
     As described above, the sheet placing unit  20  can be lifted or lowered along the longitudinal beams  11   a . An up-and-down mechanism for moving the sheet placing unit  20  up and down is explained as an example. 
     A motor (not shown) serving as a driving source is accommodated in the driving unit  12 . A rotation shaft (not shown) driven with rotation of the motor is arranged to project from both sides of the driving unit  12  in a width direction (a right-and-left direction in  FIG. 2A ). A gear (not shown) is attached to each end of the rotation shaft. A rack (not shown) is arranged in and along each longitudinal beam  11   a , and slits  11   c  shown in  FIG. 1  are formed in inner sides (surfaces on which the longitudinal beams  11   a  are opposed to each other) of the longitudinal beams  11   a . The rotation shaft is arranged to insert from the slits  11   c  into the longitudinal beams  11   a . The gears arranged on the ends of the rotation shaft are engaged with the racks of the longitudinal beams  11   a . This configuration enables the sheet placing unit  20  to be lifted or lowered to a predetermined position by controlling the rotation of the motor of the driving unit  12 . 
     As shown in  FIG. 2C , a switch  16  for controlling up-and-down movement of the sheet placing unit  20  is provided on the back side of the right-side longitudinal beam  11   a . The switch  16  is a slide switch to enable a one-handed operation. Moreover, as shown in  FIG. 2C , a switch  17  is provided on the back side of the left-side longitudinal beam  11   a . The switch  17  controls the motor of the driving unit  30  for moving the supporting plate  23  shown in  FIG. 6 . The switch  17  is also a slide switch to enable a one-handed operation. In the embodiment, the sheet placing unit  20  is lifted and lowered by sliding the switch  16  up and down, and the supporting plate  23  is moved up and down by sliding the switch  17  up and down. Moving the supporting plate  23  up and down means moving it up and down with respect to one of the guiding plates  21  (the guiding plate  21  by which the supporting plate  23  is supported when the bottom of the sheet holding space  26  is opened). The motors of both the driving unit  12  and the driving unit  30  are driven by electric power from the battery  18  shown in  FIGS. 2B and 2C . The battery  18  can be charged. 
     The positions of the switches  16  and  17  can be adjusted on the longitudinal beams  11   a  in an up-and-down direction, so that a user can change the positions of the switches  16  and  17  depending on the height of the user considering ease of use, whereby their usability is improved. 
     As described above, the guiding plates  21  are attached to and supported by the driving unit  12  through the supporting arms  24 . The guiding plates  21  are supported by the supporting arms  24  in such a manner that the guiding plates  21  can move in a right-and-left direction in  FIG. 2A . Thus, as shown in  FIG. 8 , the guiding plates  21  can be moved away from or close to each other. 
     Next, an operation of supplying sheets by the sheet supply/convey supporting device  1  that has the above configuration is explained. 
     First, as shown in  FIG. 8 , the guiding plates  21  are moved away from or close to each other to fit a width of stacked sheets. The supporting plate  23  is positioned to close the bottom of the sheet holding space  26 . If the bottom of the sheet holding space  26  is opened, the supporting plate  23  is moved to close the bottom. 
     As shown in  FIG. 1 , the sheet stack P is placed on the supporting plate  23  between the guiding plates  21  (the sheet stack P is held in the sheet holding space  26 ). Then, as shown in  FIG. 9 , both sides of the sheet stack P are caught and guided by the ribs  21   a  provided to the guiding plates  21 . The ribs  21   a  enable a reliable guidance of the sides of the sheet stack P and reduction in friction with the sheet stack P when placing the sheet stack P. 
     The sheet supply/convey supporting device  1  that carries the sheet stack P is moved to a position of an image forming apparatus  100  at which the sheet stack P is to be supplied. It is preferable in view of stability that the sheet placing unit  20  is lowered in moving the sheet supply/convey supporting device  1  as shown in  FIG. 1 . 
     As shown in  FIG. 10 , a feeding tray  101  of the image forming apparatus  100  is pulled out, and the sheet placing unit  20  is lifted (in a case in which the sheet placing unit  20  is lowered) to arrange it to a higher position than the feeding tray  101 . The lateral beams  11   b  are then inserted under the feeding tray  101  to position the sheet placing unit  20  over the feeding tray  101 . At that time, to precisely position the sheet placing unit  20 , the carriage  10  is positioned by applying the guide bar  14  on the carriage  10  to a front surface of the feeding tray  101  as shown in  FIG. 11 . A stop lever (not shown) is provided to the casters  15 , so that the sheet supply/convey supporting device  1  does not move when the stop lever is operated. 
     Next, the guiding plates  21  are moved apart from each other to have a larger space therebetween than a width of a sheet. Thus, the sheet stack P is held on the supporting plate  23  between the guiding plates  21 . The switch  16  is operated, so that the sheet placing unit  20  is lowered to a position at which sheets are placed in the feeding tray  101 . Furthermore, as shown in  FIG. 12 , the supporting plate  23  is pulled up by operating the switch  17  (or by hand) (with respect to one of the guiding plates  21 ) to open the bottom of the sheet holding space  26 . When the bottom of the sheet holding space  26  is opened by moving the supporting plate  23 , the sheet stack P is supplied to the feeding tray  101 . 
     The sheet placing unit  20  is then lifted from the feeding tray  101  as shown in  FIG. 13 . The bottom of the sheet holding space  26  can be closed by lowering the supporting plate  23  to prepare for the next sheet stack. Thus, supplying sheets has completed, so that the sheet supply/convey supporting device  1  is moved away from the image forming apparatus  100 . 
     If the supporting plate  23  is moved by the driving unit  30  as shown in  FIG. 6 , the supporting plate  23  can be automatically lowered to close the bottom of the sheet holding space  26  after sheets are supplied and the sheet placing unit  20  is lifted. Specifically, the supporting plate  23  can be moved (the bottom of the sheet holding space  26  can be closed) a predetermined time after sheets are supplied and the sheet placing unit  20  is lifted. Alternatively, it is preferable that timing at which the supporting plate  23  is automatically lowered can be adjusted (the bottom of the sheet holding space  26  is closed). 
     The sheet supply/convey supporting device  1  according to the embodiment can assist supplying sheets to a sheet cassette or a sheet tray with a common configuration in an ordinary image forming apparatus, thereby reducing efforts of supplying sheets. Even women or elderly people can easily and reliably supply sheets because it is unnecessary to manually lift or convey a heavy sheet stack. Moreover, a large number of sheets can be supplied at a time whereby it is possible to reduce a frequency of operations. 
     The guiding plates  21  guide both sides of sheets, so that the sheets are not scattered during their conveyance. Furthermore, it is possible to prevent sheets from falling down because the supporting plate  23  holds the sheets from the bottom. 
     If the supporting plate  23  is moved by the driving unit  30 , the supporting plate  23  can be moved even if a large stack of sheets is placed thereon, enabling to reliably supply the sheets. 
     The ribs  21   a  provided to the inner sides of the guiding plates  21  come into contact with sides of sheets, so that static electricity between sheets is removed, so that it is possible to prevent sheets from sticking together or from being improperly supplied. 
     The handles  13  are formed to be vertically long, so that the sheet supply/convey supporting device  1  can be operated by an operator irrespective of the height of the operator. 
     The sheet supply/convey supporting device  1  can be also used, in addition to supplying unused sheets, to take out and convey printed sheets discharged to a discharging tray. Next, an operation of taking out and conveying printed sheets is explained. 
     As shown in  FIG. 14 , a stack of output sheets (printed sheets) PP is stacked on a discharging tray  103  provided to a side of a discharging device  102  of the image forming apparatus  100 . The sheet supply/convey supporting device  1  can be used to take out and convey the large number of printed sheets PP. 
     As shown in  FIG. 15 , the sheet supply/convey supporting device  1  is moved to the side of the discharging device  102  to oppose the discharging tray  103 . The sheet placing unit  20  is moved to a position corresponding to the discharging tray  103  by operating the switch  16 . The carriage  10  is moved to bring an edge of the sheet placing unit  20  into contact with the discharging tray  103 , so that the discharging tray  103  and the sheet placing unit  20  are arranged consecutively. The stop lever for the casters  15  is operated to stop moving the sheet supply/convey supporting device  1 . Then, the printed sheets PP stacked on the discharging tray  103  are slid and moved onto the supporting plate  23 . Thereafter, the sheet supply/convey supporting device  1  is moved to a desired position. After the sheet placing unit  20  is lowered or lifted, the supporting plate  23  is moved to open the bottom of the sheet holding space  26 , so that the printed sheets PP can be placed on a desired position. 
     As a mechanism for lowering or lifting the sheet placing unit  20  is configured such that a rack is arranged in the longitudinal beams  11   a . However, for example, a mechanism in which a worm bar (a bar-shaped screw) is used can be also adapted. Specifically, a worm bar is arranged in the longitudinal beams  11   a , and the guiding plates  21  are joined with bolts engaged with the worm bar through a supporting member. With this mechanism, it is possible to lift or lower the guiding plates  21 , that is, the sheet placing unit  20 , by rotating the worm bar. In the case of the configuration, a driving unit to drive the worm bar can be arranged on a side of the mainframe  11 . Alternatively, an up-and-down mechanism that uses a chain can be adapted. 
     An appropriate configuration can be adapted for a frame forming the carriage  10 . Likewise, a shape of the guiding plates  21  constituting the sheet placing unit  20  can be also properly changed. An appropriate configuration can be adapted for a driving mechanism of the supporting plate  23 . 
     The sheet supply/convey supporting device  1  can supply sheets not only to a front-loading-type sheet tray/cassette but also to a side-loading-type sheet tray/cassette of an image forming apparatus or the like. Furthermore, the sheet supply/convey supporting device  1  can be effectively used to an optional feeding device such as a feeding tray for a large number of sheets that is provided to a main body of an image forming apparatus. 
     According to an aspect of the present invention, efforts of supplying sheets can be reduced. 
     Furthermore, according to another aspect of the present invention, even women or elderly people can easily and reliably supply a heavy sheet stack, and it is possible to reduce a frequency of operations. 
     Moreover, according to still another aspect of the present invention, even a large number of stacked sheets can be easily supplied. 
     Furthermore, according to still another aspect of the present invention, it is possible to support sheets with a different size and, even in that case, reliably guide the sheets. In addition, resistance generated when the sheet placing unit is lifted after sheets are supplied can be removed. 
     Moreover, according to still another aspect of the present invention, it is possible to reliably guide sides of sheets, reduce friction in placing sheets, and remove static electricity between placed sheets. 
     Furthermore, according to still another aspect of the present invention, the supporting plate can be guided and moved without trouble, particularly, at a time of moving the supporting plate to a closing position. 
     Moreover, according to still another aspect of the present invention, it is possible to properly position the sheet supply/convey supporting device and to preciously supply sheets to the sheet accommodating unit. This makes it possible to prevent sheets from being improperly supplied. 
     Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.