Abstract:
Workers are given guidance about which goods are to be picked up out of a storage unit. A warehouse system is provided, which includes: position information obtaining means for searching, in a storage unit, in which a plurality of articles of goods each including an identification code section are stored, the position of the identification code section that is related to the identification code of one of the plurality of articles of goods that is an object to be worked on, and obtaining information of this position; and position guidance means for giving guidance to a worker about the position of the article of goods that is the object to be worked on, based on the information obtained by the position information obtaining means.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a warehouse system and a guidance method for picking work. 
       BACKGROUND ART 
       [0002]    In Patent Literature 1, there is disclosed a system in which an indicator is placed in a picking zone (picking work position) and, when a storage unit called a pallet is conveyed to the picking zone by a conveyor, the number of articles of goods to be picked up out of the storage unit is displayed on the indicator. According to this system, a worker can pick up a correct number of articles of goods by looking at the indicator. 
       CITATION LIST 
     Patent Literature 
       [0003]    [Patent Literature 1] JP 2009-196818 A 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0004]    However, the premise of the background art described above is that the all of the plurality of articles of goods stored in one storage unit are of one type. Looking at the indicator therefore does not help the worker in figuring out which type of goods to pick up when one storage unit stores a plurality of types of goods. 
         [0005]    The present invention has been made in view of the problem described above, and an object of the present invention is therefore to provide a warehouse system and a guidance method for picking work that are capable of giving guidance to workers about which goods to pick up out of a storage unit. 
       Solution to Problem 
       [0006]    In order to solve the problem described above, according to one embodiment of the present invention, there is provided a warehouse system including: position information obtaining means for searching a storage unit, in which a plurality of articles of goods each including an identification code section are stored, in order to find out a position in the storage unit of the identification code section that is related to an identification code of one of the plurality of articles of goods that is an object to be worked on, to thereby obtain information of this position; and position guidance means for giving guidance to a worker about the position of the article of goods that is an object to be worked on, based on the information obtained by the position information obtaining means. 
         [0007]    Further, according to one embodiment of the present invention, there is provided a picking work guidance method, including: a position information obtaining step of searching a storage unit in which a plurality of articles of goods each including an identification code section are stored, in order to find out a position in the storage unit of the identification code section that is related to an identification code of one of the plurality of articles of goods that is an object to be worked on, to thereby obtain information of this position; and a position guidance step of giving guidance to a worker about the position of the article of goods that is an object to be worked on, based on the information obtained in the position information obtaining step. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]      FIG. 1  is a diagram for schematically illustrating the planar configuration of a warehouse system according to an embodiment of the present invention. 
           [0009]      FIG. 2  is an enlarged perspective view of a workspace. 
           [0010]      FIG. 3  is a frontal view of the workspace. 
           [0011]      FIG. 4  is a side view of a camera position. 
           [0012]      FIG. 5  is a side view of a picking work position. 
           [0013]      FIG. 6  is a diagram for illustrating the internal configuration of a light ray unit. 
           [0014]      FIG. 7  is a side view of an warehousing work position. 
           [0015]      FIG. 8  is a block diagram for illustrating a control configuration of the warehouse system according to the embodiment of the present invention. 
           [0016]      FIG. 9  is a diagram for schematically illustrating data in a storage unit database. 
           [0017]      FIG. 10  is a flow chart for illustrating processing of a warehousing/dispatching control system. 
           [0018]      FIG. 11  is a diagram for illustrating an example of an image photographed with the camera. 
           [0019]      FIG. 12  is a diagram for illustrating a storage unit that is being irradiated with a ray of light. 
           [0020]      FIG. 13  is a diagram for illustrating a modification example of the warehouse system according to the embodiment of the present invention. 
           [0021]      FIG. 14  is a diagram for illustrating another modification example of the warehouse system according to the embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0022]    An embodiment of the present invention is described in detail below with reference to the drawings. 
         [0023]      FIG. 1  is a diagram for schematically illustrating the overall configuration of a warehouse system according to the embodiment of the present invention.  FIG. 2  is an enlarged perspective view of a workspace  10   a  included in a warehouse system  10 . The warehouse system  10  includes an automated warehouse  12 . The automated warehouse  12  houses a large number of box-shaped storage units, which contains stock items. The storage units are not limited to a box shape and may have other shapes such as a tray shape. Connected to the automated warehouse  12  is storage unit conveying means, which includes a unloading conveyor (unloading conveying means)  18 , workspace conveyors (work stages)  19 , and a loading conveyor (loading conveying means)  20 . These are roller conveyors or belt conveyors. The warehouse system  10  also includes a plurality of workspaces  10   a  in each of which a worker performs warehousing/picking work. The warehouse system  10  further includes an arrival article conveyor (arrival item conveying means)  22  configured to convey arrival items  40  from an arrival space  14  to the respective workspaces  10   a,  and a dispatch conveyor (dispatching item conveying means)  24  configured to convey dispatching items  42  from the respective workspaces  10   a  to a dispatching space  16 . These are roller conveyors or belt conveyors as well. The arrival space  14  is a place at which the arrival items  40  arrive from the outside. The dispatching space  16  is a place where dispatching preparations such as packaging take place. 
         [0024]    The automated warehouse  12  includes, for example, a plurality of storage racks each having multiple shelves and arranged side by side. The automated warehouse  12  includes conveying means that includes a driving source such as a motor so that storage units can be conveyed inside the automated warehouse  12 . The conveying means can be, for example, a belt conveyor or a roller conveyor, or a self-propelled robot configured to carry a storage unit, in the case of conveyance in the horizontal direction. In the case of conveyance in the perpendicular direction, the conveying means is an electric lift, for example. A storage unit is conveyed by one of these means to a spot specified by a warehousing/dispatching control system  62 , which is described later, to be kept there for storage. A storage unit selected by the warehousing/dispatching control system  62  is conveyed from its storage location to the outside of the automated warehouse  12  by the conveying means, and then conveyed by the unloading conveyor  18  to one of the workspaces  10   a.    
         [0025]    The upstream end of the unloading conveyor  18  is connected to the automated warehouse  12 . The downstream end of the unloading conveyor  18  is branched into a plurality of branches in a comb-teeth pattern. Each of the plurality of branches is called a workspace branch portion  18   a,  the downstream end of which is connected to the upstream end of one of the workspace conveyors  19 . 
         [0026]    Each workspace  10   a  includes a work platform  28  on which a worker stands. The workspace conveyor  19  is straight and relatively-short conveying means that is provided in front of the work platform  28  of each workspace  10   a.  The workspace conveyor  19  conveys each storage unit  26  from one of the left side and right side of the worker (here, the right side) to the other of the left side and the right side (here, the left side). The workspace conveyor  19  is also a work stage where the worker standing on the work platform  28  takes a dispatch item  42  out of the storage unit  26  being conveyed on the workspace conveyor  19 , and where the worker adds an arrived item  40  to the storage unit  26  being conveyed. The workspace conveyor  19  is controlled so that the storage unit  26  stops once at a picking work position, which is at the middle of the workspace conveyor  19 , and at an warehousing work position, which is at the downstream end (here, the left end) of the workspace conveyor  19 , for the worker to work on the storage unit  26 . While a conveyor that includes a driving source serves as a work stage here, a simple table-shaped work stage without a driving source maybe employed to move the storage unit  26  by hand from the upstream end to the downstream end. 
         [0027]    The worker stands on the work platform  28 , takes the dispatch item  42  of interest out of the storage unit  26  at the middle of the workspace conveyor  19  (picking work position), and puts this item on a workspace branch portion  24   a  of the dispatch conveyor  24 . The worker also receives one arrival item  40  from the distal end (downstream end) of a workspace branch portion  22   a  of the arrival article conveyor  22  at the downstream end of the workspace conveyor  19  (warehousing work position), and puts this item in the storage unit  26 . The worker operates an operation unit  30 , which is a display device with a touch panel so that the storage unit  26  is conveyed by a loading conveyor  20  to be returned back to the automated warehouse  12 . 
         [0028]    The upstream end of the loading conveyor  20  is branched into a plurality of branches in a comb-teeth pattern. Each of the plurality of branches is called a workspace branch portion  20   a,  and the workspace branch portions  20   a  merge into one at some point along the way. The upstream end of each workspace branch portion  20   a  is connected to the downstream end of one of the workspace conveyors  19 . The downstream end of the loading conveyor  20  is connected to the automated warehouse  12 . 
         [0029]    The dispatch conveyor  24  described above also has the upstream end branched into a plurality of branches in a comb-teeth pattern. Each of the plurality of branches serves as the workspace branch portion  24   a,  which stretches toward the relevant workspace conveyor  19 . The arrival article conveyor  22  also has the downstream end branched into a plurality of branches in a comb-teeth pattern. Each of the plurality of branches serves as the workspace branch portion  22   a,  which stretches toward the relevant workspace conveyor  19 . 
         [0030]    In short, for each workspace conveyor  19 , the workspace branch portion  18   a  of the unloading conveyor  18 , the workspace branch portion  24   a  of the dispatch conveyor  24 , the workspace branch portion  22   a  of the arrival article conveyor  22 , and the workspace branch portion  20   a  of the loading conveyor  20  are placed on one side of the workspace conveyor  19 , and stretch linearly toward the workspace conveyor  19 . The workspace branch portion  22   a  is placed above the workspace branch portion  20   a  so that the two overlap with each other in plan view. The downstream end of the workspace branch portion  22   a  flanks a side of the workspace conveyor  19 . 
         [0031]    The downstream end of the workspace branch portion  18   a  is connected to the upstream end of the workspace conveyor  19 , and the upstream end of the workspace branch portion  22   a  is connected to the downstream end of the workspace conveyor  19 . The workspace branch portion  24   a  stretches in a space between the workspace branch portion  18   a  and the workspace branch portion  20   a  along the workspace branch portions  18   a  and  20   a,  and the upstream end of the workspace branch portion  24   a  flanks a side of the workspace conveyor  19 . 
         [0032]    In each workspace  10   a,  the workspace branch portions  18   a,    20   a,    22   a,  and  24   a  all have conveyance directions that are perpendicular with respect to the conveyance direction of the workspace conveyor  19  in plan view. The conveyance directions of the workspace branch portions  18   a,    20   a,    22   a,  and  24   a  are also parallel to one another in plan view. A conveyance path made up of the workspace branch portion  18   a,  the workspace conveyor  19 , and the workspace branch portion  20   a  therefore has two turning points along the way. The direction in which the storage unit  26  is conveyed changes by 90 degrees in a direction that is the same at every turning point (for example, the clockwise direction in plan view). The workspace conveyors  19  in the respective workspaces  10   a  are parallel to one another and, in a particular arrangement used here, aligned along the same straight line. 
         [0033]    Employing the above-mentioned layout in each workspace  10   a  enables a single worker to handle with ease both picking work for taking a dispatching item out of the storage unit  26  and arrival storing work for putting an arrival item in the storage unit  26 . The picking work position and the warehousing work position in this case are adjacent to each other, which makes traveling between the two spots quite easy. A worker who takes a dispatching item out of a storage unit at the picking work position knows free space in the storage unit well. The worker can therefore quickly put an arrival item in the storage unit at the warehousing work position. Each workspace  10   a  is very compact in width so that a plurality of workspaces  10   a  can be placed next to one another in a narrow space. Alternatively, two workers may be assigned to each workspace  10   a,  with one worker positioned in front of the picking work position and the other worker positioned in front of the warehousing work position, so that picking work and warehousing work are divided between the two. 
         [0034]    A further detailed description is given on the workspaces  10   a.    FIG. 3  is a view of one workspace  10   a  viewed from the work platform  28  side, in other words, a frontal view of the workspace  10   a.    FIG. 4  is a side view for illustrating the layout of the upstream end of one workspace conveyor  19 .  FIG. 5  is a side view for illustrating the layout of the picking work position in the workspace conveyor  19 .  FIG. 6  is a diagram for illustrating the internal configuration of a light ray unit  38 , which is illustrated in  FIG. 5 .  FIG. 7  is a side view for illustrating the layout of the warehousing work position in the workspace conveyor  19 . 
         [0035]    As illustrated in  FIG. 3  and  FIG. 4 , the storage unit  26  that has been conveyed by the workspace branch portion  18   a  of the unloading conveyor  18  to the workspace  10   a  stops once at a camera position, which is at the downstream end of the workspace branch portion  18   a.  A bar code indicating identification information with which the storage unit  26  is identified uniquely is stuck to the storage unit  26 . A storage unit bar code reader  50  is provided near the camera position to read the bar code stuck to the storage unit  26 . The method of identifying the storage unit  26  is not limited to the one described above, and, for example, a mark or a number may be written to be recognized for identification. An RFID tag may instead be attached to the storage unit  26 . Alternatively, a medium on which magnetic identification information or identification information in the form of color codes is recorded may be attached to the storage unit  26 . 
         [0036]    A camera  32  placed above the camera position photographs an image of the interior of the storage unit  26  (see  FIG. 11 ). The storage unit  26  is shaped like a box with an open top, and the camera  32  is positioned so that the camera  32  photographs in the perpendicularly downward direction. An internal image of the storage unit  26  can thus be obtained with the camera  32 , and the image indicates what is contained in the storage unit  26 . The storage unit  26  contains one or more boxes of stock items in a manner that avoids stacking one box on top of another. The storage unit  26  contains the one or more boxes of stock items also in a manner that makes a bar code (identification code image) stuck to or printed on one of the side surfaces of each box visible from above (see  FIG. 11 ). In other words, the box of stock items is contained in the storage unit  26  with a surface that has the bar code thereon facing skyward. All boxes of stock items that are contained in the storage unit  26  are accordingly captured in an image obtained with the camera  32 , and the bar codes of the respective boxes are captured in the image as well. Identification information for uniquely identifying the type of an item to which a bar code is affixed can be obtained from the bar code. With the identification information, additional information such as the size, color, and manufacturing date of the item may or may not be identified as well. Information sufficient to identify an object to work on (here, picking work) can be obtained from the bar code. The bar code may be a one-dimensional bar code or a two-dimensional bar code. The method of affixing identification information to each box is not limited to bar codes, and any method can be used to affix identification information to each box as long as the identification information is recognizable from a photographed image. For example, a mark, letter, or number indicating identification information may be written on a box in a specific mode to be recognized from a photographed image. 
         [0037]    After being photographed, the storage unit  26  at the camera position is conveyed to the upstream end of the workspace conveyor  19  when there are no other storage units  26  at the upstream end of the workspace conveyor  19 . The storage unit  26  at the upstream end of the workspace conveyor  19  is conveyed to the picking work position in the workspace conveyor  19  when there are no other storage units  26  at the picking work position. 
         [0038]    As illustrated in  FIG. 3  and  FIG. 5 , another storage unit bar code reader  52  is provided at the picking work position to read the bar code stuck to the storage unit  26 . The worker at the picking work position takes a dispatching item out of the storage unit  26 . At this point, a light ray R emitted from the light ray unit  38 , which is provided above the workspace conveyor  19 , hits the dispatching item inside the storage unit  26 . Specifically, the warehouse system  10  identifies the position of the dispatching item based on an image photographed at the camera position, and emits the light ray R toward the identified position. The light ray unit  38  includes, as illustrated in  FIG. 6 , a laser light source  38   a  configured to emit laser light, a movable mirror  38   b  provided right in front of the laser light source  38   a  and configured to reflect laser light that is emitted from the laser light source  38 , thereby leading the light lay R to the outside of the light ray unit  38 , and an actuator  38   c  configured to change the direction of the movable mirror  38   b.  The turning on/off of laser light and the direction of the movable mirror  38   b  are controlled by the warehousing/dispatching control system  62 . In other words, the light ray unit  38  is capable of emitting the light ray R in any direction under control of the warehousing/dispatching control system  62 . With a light spot (see  FIG. 12 ) formed by the light ray R, the worker immediately sees which item is to be taken out of the storage unit  26 . The method of pointing out a dispatching item is not limited to the one described above. For example, An X-Y stage may be used instead of the movable mirror  38   b  to move the laser light source  38  along two intersecting axes and emit laser light in the same direction from an arbitrary point. Another example is to irradiate the dispatching item with spot light instead of the laser light source  38 , and still another example is to point the dispatching item with a mechanically-controlled pointer stick. Alternatively, the dispatching item may be pointed out by a robotic arm. An image that makes the box of an item to be dispatched distinguishable may also be used to point out the dispatching item. The image is created by, for example, affixing a marker to the box of the item in an image obtained with the camera  32  which captures all boxes of stock items contained in the storage unit  26 , and the created image is displayed on the display device. Also in this manner, the worker understands which box is to be taken out. 
         [0039]    When the worker takes the dispatching item  42  out of the storage unit  26  and brings the bar code of the dispatching item  42  close to a dispatching item bar code reader  34 , which is provided above and behind the storage unit  26 , the dispatching item bar code reader  34  reads the bar code. The worker then puts the dispatching item  42  at the upstream end of the workspace branch portion  24   a  of the dispatch conveyor  24  which is located below the dispatching item bar code reader  34 , causing the dispatch conveyor  24  to convey the dispatching item  42  to the dispatching space  16 . At the dispatching space  16 , dispatching preparations such as packaging are made by hand or by machines. The upstream end of the workspace branch portion  24   a  is positioned at a level slightly higher than the storage unit  26  at the picking work position, and the dispatching item bar code reader  34  is provided above the upstream end of the workspace branch portion  24   a.  This facilitates picking work for the worker. 
         [0040]    When the bar code of the correct dispatching item  42  is read by the dispatching item bar code reader  34  and there are no other storage units  26  at the warehousing work position in the workspace conveyor  19 , the storage unit  26  at the picking work position is conveyed to the warehousing work position. 
         [0041]    At the warehousing work position, one arrival item  40  has been conveyed to the downstream end of the workspace branch portion  22   a  of the arrival article conveyor  22  as illustrated in  FIG. 3  and  FIG. 7 . The worker picks up this arrival item  40  with hands and brings a bar code stuck to or printed on the box close to an arrival item bar code reader  36 , which is provided above the downstream end of the workspace branch portion  22   a,  and the arrival item bar code reader  36  reads the bar code. The worker then houses the arrival item  40  in free space in the storage unit  26  located below and on the near side of the arrival item bar code reader  36 . The storage unit  26  from which the dispatching item  42  has been taken out at the picking work position is likely to have free space. The arrival item bar code reader  36  is provided above the downstream end of the workspace branch portion  22   a,  and the downstream end of the workspace branch portion  22   a  is positioned at a level higher than the storage unit  26  at the warehousing work position. This facilitates arrival storing work for the worker. 
         [0042]    As illustrated in  FIG. 3 , a gap S between the storage unit  26  at the warehousing work position and the storage unit  26  at the picking work position is less than a width W (length in the conveyance direction) of each storage unit  26 . This allows the worker to move quickly from a spot in front of the picking work position to a spot in front of the warehousing work position. 
         [0043]    The operation unit  30  displays a “completed” button and an “uncompleted” button. When one of the buttons is touched by the worker, the storage unit  26  is moved from the warehousing work position onto the loading conveyor  20 , and conveyed to the automated warehouse  12  by the loading conveyor  20 . Specifically, the worker touches the completed button when determining visually that the storage unit  26  has free space in which one or more arrival items can additionally be housed. When determining that there is no such free space, the worker touches the uncompleted button. Information indicating whether the storage unit  26  is completed or uncompleted (completion flag) and the identification information of the arrival item  40  which is obtained from the bar code are stored in a storage unit database  68  in association with the identification information of the storage unit  26  (see  FIG. 8 ). 
         [0044]      FIG. 8  is a diagram for illustrating a control configuration of the warehouse system according to the embodiment of the present invention. The warehouse system  10  mainly includes a stock management system  60 , the warehousing/dispatching control system  62 , and a conveyance control system  64 . The systems  60 ,  62 , and  64  are each built from one or more computers. 
         [0045]    A stock management database  66  is connected to the stock management system  60  to manage what item is in stock in what quantity. The stock management system  60  also instructs the warehousing/dispatching control system  62  to dispatch an item. 
         [0046]    The conveyance control system  64  is connected to conveyance machines, which include the unloading conveyor  18 , the workspace conveyor  19 , the loading conveyor  20 , the arrival article conveyor  22 , and the dispatch conveyor  24 . The conveyance control system is also connected to the automated warehouse  12 . The warehousing/dispatching control system  62  issues an instruction to the conveyance control system  64  about where in the automated warehouse  12  the storage unit  26  for which the arrival storing work has been finished is to be kept for storage. The warehousing/dispatching control system  62  also issues an instruction to the conveyance control system  64  about which storage unit  26  is to be conveyed from the automated warehouse  12  to which workspace  10   a.  Following these instructions of the warehousing/dispatching control system  62 , the conveyance control system  64  controls the conveyance of each storage unit  26 . 
         [0047]    Connected to the warehousing/dispatching control system  62  are the camera  32 , the storage unit bar code readers  50  and  52 , the dispatching item bar code reader  34 , the arrival item bar code reader  36 , the operation unit  30 , and the light ray unit  38 . The stock management system  60 , the conveyance control system  64 , and the storage unit database  68  are also connected to the warehousing/dispatching control system  62 . The warehousing/dispatching control system  62  receives from the stock management system  60  an instruction to dispatch an item, and refers to the storage unit database  68  to determine which storage unit  26  contains the item and where in the automated warehouse  12  this storage unit  26  is kept. The warehousing/dispatching control system  62  also determines in which workspace  10   a  the item is to be worked on. For example, the workspace  10   a  in which the instructed work is to take place may be determined so that the workload is uniform in each workspace  10   a.  The warehousing/dispatching control system  62  then issues an instruction to the conveyance control system  64  about where the storage unit  26  to be conveyed is kept and to which workspace  10   a  the storage unit  26  is to be conveyed. The conveyance control system  64  conveys the storage unit  26  following this instruction as described above. 
         [0048]    The warehousing/dispatching control system  62  also identifies the spot in the storage unit  26  of the dispatching item  42  based on an image of the storage unit  26  which is obtained with the camera  32  connected to the warehousing/dispatching control system  62 . The warehousing/dispatching control system  62  controls the emission direction of the light ray unit  38  so that the light ray R hits the identified spot. 
         [0049]    The warehousing/dispatching control system  62  also obtains identification information of the arrival item  40  from the bar code read by the arrival item bar code reader  36 , and notifies the identification information to the stock management system  60 . Receiving the notification, the stock management system  60  updates the stock quantity. 
         [0050]    The warehousing/dispatching control system  62  determines a destination to which the storage unit  26  at the warehousing work position is to be moved as well. In other words, where in the automated warehouse  12  the storage unit  26  is to be kept is determined. The storage location where the storage unit  26  is kept in the automated warehouse  12  may be determined at random, or with the use of a more intelligent algorithm. For example, the storage units  26  that contain items expected to be dispatched in the near future (e.g., items for the current season) may be kept on the near side within the automated warehouse  12 , while other storage units  26  are kept in the back of the automated warehouse  12 . This way, the storage unit  26  that leaves the warehouse frequently can be kept in a spot from which the storage unit  26  can be taken out immediately. The conveyance control system  64  is instructed about the destination to which the storage unit  26  is to be moved, and conveys the storage unit  26  following the instruction. As illustrated in  FIG. 9 , the storage unit database  68  stores, for each storage unit  26 , in association with identification information of the storage unit  26 , information about where in the automated warehouse  12  the storage unit  26  is kept (storage location), information indicating whether or not the storage unit  26  has free space (completion flag), and identification information of items contained in the storage unit  26 . The warehousing/dispatching control system  62  updates data in the storage unit database  68 . 
         [0051]    In the case where there are more arrival items  40  than the dispatching items  42 , the warehousing/dispatching control system  62  calls up the storage units  26  to the workspaces  10   a  that are recorded as having free space (completion flag=“0”) in the storage unit database  68 . 
         [0052]      FIG. 10  is a flow chart for illustrating processing of the warehousing/dispatching control system  62 . The operation illustrated in  FIG. 10  is executed each time an instruction to dispatch an item is received from the stock management system  60 . In the case where item dispatching instructions are issued in succession in a short span, the warehousing/dispatching control system  62  executes a plurality of streams of the processing illustrated in  FIG. 10  in parallel to one another. The dispatching instruction includes identification information of the item. The warehousing/dispatching control system  62  receives from the stock management system  60  an instruction to dispatch an item (S 101 ), and reads out of the storage unit database  68  the identification information and storage location of one storage unit  26  that are associated with the identification information of the item to be dispatched (S 102 ). The warehousing/dispatching control system  62  notifies the read identification information and storage location of the storage unit  26  to the conveyance control system  64 , and instructs to take the storage unit  26  out of the warehouse (S 103 ). The warehousing/dispatching control system  62  then waits for the arrival of the storage unit  26  instructed to be taken out of the warehouse at the camera position (S 104 ). Specifically, the warehousing/dispatching control system  62  uses the storage unit bar code reader  50  to read the bar code of the storage unit  26  that is at the camera position, and examines whether or not identification information obtained from the read bar code matches the identification information obtained in Step S 102 . When the read identification information and the obtained identification information match, it is determined that the storage unit  26  instructed to be taken out of the warehouse has arrived at the camera position. When the storage unit  26  arrives at the camera position, the warehousing/dispatching control system  62  instructs the camera  32  to photograph and obtains a photographed image of the interior of the storage unit  26  (S 105 ).  FIG. 11  is an illustration of an example of an image photographed with the camera  32 . As illustrated in  FIG. 11 , the edge of the opening of the storage unit  26  is photographed in the image and boxes of stored items  41  can be seen inside the edge. In this warehouse system  10 , where workers house boxes of the stored items  41  in the storage units  26  so that bar codes face skyward, a bar code  41   a  of each box is captured in the image as well. 
         [0053]    The warehousing/dispatching control system  62  identifies the position of each bar code  41   a  in the image obtained with the camera  32  to obtain information of this position, and also decodes item identification information from each bar code  41   a  (S 106 ). For example, a spot in the image obtained with the camera  32  that has a plurality of parallel black bands on a white base may be scanned and identified as the position of the bar code  41   a.  The warehousing/dispatching control system  62  next identifies the position of the bar code  41   a  that corresponds to the item identification information received in Step S 101  from the stock management system  60  (S 107 ). In this manner, the position of the bar code  41   a  that corresponds to the identification information of the item to be dispatched is looked for and information of the position is obtained. 
         [0054]    The warehousing/dispatching control system  62  then waits for the arrival of the storage unit  26  at the picking work position in the same manner as in Step S 104  (S 108 ). When the storage unit  26  arrives at the picking work position, the light ray unit  38  is instructed to emit the light ray R to a bar code that is at the position identified in Step S 107  (S 109 ). The light ray R thus hits the dispatching item  42  of interest.  FIG. 12  is a diagram for illustrating a storage unit that is being irradiated with the light ray R. Alight spot  70  appears at the bar code position of the box of the item to be taken out by the worker. Specifically, the relative position of the dispatching item  42  relative to the position of the movable mirror  38   b  is calculated based on the position identified in Step S 107 . The direction of the movable mirror  38   b  is calculated based on the calculated position. There may be cases where it is found in Step S 107  that the bar code  41   a  that corresponds to the item identification information received in Step S 101  from the stock management system  60  does not appear in the image obtained in Step S 105 . This can happen when, for example, the item to be dispatched is not contained in the storage unit  26  by some accident, or boxes are not put in the storage unit  26  with the bar codes facing skyward. The light ray R is not emitted in Step S 109  in such cases . This informs the worker of an error. 
         [0055]    The warehousing/dispatching control system  62  then waits for the dispatching item bar code reader  34  to read the item identification information received in Step S 101  from the stock management system  60  (S 110 ). When this identification information is read, the warehousing/dispatching control system  62  instructs the conveyance control system  64  to convey the storage unit  26  from the picking work position to the warehousing work position (S 111 ). The conveyance control system  64  advances the storage unit  26  from the picking work position to the warehousing work position if there are no other storage units  26  at the warehousing work position. 
         [0056]    The warehousing/dispatching control system  62  waits for the arrival of the storage unit  26  at the warehousing work position in the same manner as in Step S 104  and Step S 108  (S 112 ). When the storage unit  26  arrives at the warehousing work position, the worker picks up one arrival item  40  with hands and brings the item close to the arrival item bar code reader  36 . The warehousing/dispatching control system  62  thus obtains identification information of the arrival item (S 113 ). The warehousing/dispatching control system  62  then receives touch operation in which the completed button or the uncompleted button on the operation unit  30  is touched (S 114 ). When the completed button or the uncompleted button is touched, the warehousing/dispatching control system  62  stores in the storage unit database  68  the identification information of the arrival item  40  that has been obtained in Step S 113  and the completion flag indicating the type of the button that has been touched in the touch operation received in Step S 114 , in association with the identification information of the storage unit  26  that has been obtained in Step S 112 . The warehousing/dispatching control system  62  also transmits the identification information of the arrival item  40  to the stock management system  60  (S 116 ). With the received identification information, the stock management system  60  updates the stock quantity of this item. The warehousing/dispatching control system  62  then determines a storage location where the storage unit  26  is to be kept and instructs the conveyance control system  64  to convey the storage unit  26  to the storage location (S 117 ). At this point, the storage location is stored in the storage unit database  68  in association with the identification information of the storage unit  26 . 
         [0057]    According to the warehouse system  10  described above, the arrival item  40  is put in the storage unit  26  immediately after the dispatching item  42  is taken out of the same storage unit  26 , which raises the filling rate of the storage unit  26 . Efficient storing of arrival items is also accomplished. In addition, with the light ray unit  38  emitting the light ray R to the dispatching item  42 , the worker immediately sees which box is to be taken out, and the workability is accordingly improved. 
         [0058]    Needless to say, the scope of the present invention is not limited to the embodiment described above, and encompasses various modifications. For example, as illustrated in  FIG. 13 , the workspace branch portion  18   a  of the unloading conveyor  18  and the workspace branch portion  20   a  of the loading conveyor  20  may stretch toward the workspace conveyor  19  from opposite sides from each other. The worker in this case stands beside the workspace branch portion  18   a  or the workspace branch portion  20   a  to perform picking work and arrival storing work. In  FIG. 13 , each worker stands beside the workspace branch portion  18   a,  and hence a spot  61  at the middle of the workspace conveyor  19  serves as the picking work position and a spot  62  at the downstream end of the workspace conveyor  19  serves as the warehousing work position. 
         [0059]    The workspace conveyor  19  may also have a curved shape that revolves around the worker as illustrated in  FIG. 14 . The workspace conveyor  19  may have a bent shape that revolves around the worker. The downstream end of the workspace branch portion  18   a  of the unloading conveyor  18  is connected to the upstream end of the workspace conveyor  19 , and the upstream end of the workspace branch portion  20   a  of the loading conveyor  20  is connected to the downstream end of the workspace conveyor  19 . The workspace branch portion  18   a  and the workspace branch portion  20   a,  which stretch toward the workspace conveyor  19  from opposite sides from each other in  FIG. 14 , may stretch toward the workspace conveyor  19  from the same side. Two spots in the workspace conveyor  19  are selected out of a spot  63  at the upstream end, a spot  65  at the downstream end, and a spot  64  in-between, and the spot that is on the upstream side out of the selected two serves as the picking work position. The spot that is on the downstream side out of the selected two serves as the warehousing work position. This mode allows the worker to shift from picking work to arrival storing work simply by turning his/her body. 
         [0060]    In the description given above, information about the position of the dispatching item  42  in the storage unit  26  is obtained based on an identification code image that appears in an image photographed with the camera  32 . Information about the position of the dispatching item  42  in the storage unit  26  may instead be obtained by a method that does not use the camera  32 . For example, a medium from which identification information can be read electrically or magnetically (identification code section) such as an RFID tag or a magnetic tape may be attached to each box of items inside the storage unit  26  to read identification information from the medium on each box by bringing a reader of the medium close to the box. In short, each box may be scanned by the reader. The position of the dispatching item  42  in this case may be a position of the reader when reading identification information of the dispatching item  42 . Also in this manner, the position of the dispatching item  42  inside the storage unit  26  can be looked for and information of the position can be obtained. 
         [0061]    The description given above deals with a case where the light ray unit  38  serves as a guide in the warehouse system  10  configured to store commercial items. However, the light ray unit  38  is applicable also to warehouses that store other goods than commercial items, such as parts that are used in a manufacturing facility. 
         [0062]    The description given above deals with a case where the light ray unit  38  guides the worker when an item is taken out of the storage unit  26  to dispatch the item. However, the light ray unit  38  may guide the worker also when an article of goods is taken out of the storage unit  26  in order to perform such work as moth proofing and size alterations on the article.