BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a specimen preprocessing system which automatically preprocesses a live body sample such as blood and urine so as to be subjected to an analytical processing, and more particularly to a specimen preprocessing system provided with a plug opening unit for opening a plug of a specimen container. 
         [0003]    2. Description of the Related Art 
         [0004]    A specimen rack is generally structured to support approximately one to five specimen containers. The specimen container is filled with the specimen such as blood and urine collected from a subject and sealed with a plug to prevent spill of the specimen. The specimen preprocessing system is provided with a plug opening unit for opening the plug and a plug closing unit for closing the plug again for performing the specimen dispensing. Meanwhile, the specimen container has various types each having different height, configuration and plug configuration. The aforementioned generally employed plug opening unit requires the specimen containers of the same type (height, configuration, and plug configuration) to be mounted in the same rack. 
         [0005]    The user is required to confirm with respect to the type of the specimen containers to be mounted in the rack, thus putting a certain strain on the user. Inappropriate mounting of the containers in the rack may result in an error to cause the time loss due to reconfirmation, and the delay in the time from the subsequent step to the inspection report. 
         [0006]    The type of the specimen container with the plug to be mounted in the specimen rack is limited, thus deteriorating the system flexibility. 
         [0007]    Japanese Unexamined Patent Application Publication No. 2001-318104 discloses the rack with the mechanism for adjusting the height of the member for supporting each bottom of the specimen containers for the purpose of leveling the specimen containers. 
         [0008]    The disclosed process, however, requires the inspecting engineer to adjust the height of the support member for supporting each bottom of the containers so as to level the specimen containers, which is hardly different from the process for distributing the specimen containers to be leveled for each rack. 
       SUMMARY OF THE INVENTION 
       [0009]    It is an object of the present invention to provide a specimen preprocessing system with a plug opening unit which is capable of opening the plug even if the specimen containers each having a different height (plug configuration and diameter) are mounted in the same specimen rack. 
         [0010]    The present invention is structured for the purpose of achieving the aforementioned object. 
         [0011]    In one aspect of the present invention, there is provided a specimen preprocessing system which includes a determination section for determining with respect to a height of a specimen container, a specimen container lifting mechanism for lifting an opening portion of the specimen container held in a specimen rack to a same predetermined level based on determination information data of the determination section, and a plug opening mechanism for opening a plug of the specimen container lifted to the same predetermined level by the specimen container lifting mechanism. The diameter and height of the specimen container may be set to arbitrary values so long as it is formed as a test-tube-like blood collecting tube. An arbitrary type of the plug may be formed, for example, as cylindrical rubber type, plastic type and the like so long as it prevents spill of the stored specimen. The carrier line may be of any type so long as the specimen rack is carried to the processing unit. For example, the belt conveyor type, the nail push/pull type, and the robot arm type for carriage in the air may be generally employed. 
         [0012]    The user does not have to confirm the type of the specimen container to be mounted in the rack, thus lighting up the burden of the user. 
         [0013]    A plurality of the specimen containers may be selected by the user from the wide options, thus improving the flexibility of the specimen preprocessing system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Embodiment(s) of the present invention will be described in detail based on the following figures, wherein: 
           [0015]      FIG. 1  is a plan view schematically showing a plug opening unit according to an embodiment of the present invention; 
           [0016]      FIGS. 2A-2B  show operation patterns of the specimen container lifting mechanism and the plug opening mechanism in the plug opening position according to the embodiment of the present invention; and 
           [0017]      FIGS. 3A-3B  show exemplary states where the specimen containers are mounted in the specimen rack. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    An embodiment of the present invention will be described referring to  FIGS. 1 ,  2 A,  2 B,  3 A and  3 B. 
         [0019]      FIG. 1  is a plan view schematically showing a plug opening unit of a specimen preprocessing system. The plug opening unit  1  is connected to a carrier line  2  for introducing a specimen rack  4  through a specimen rack inlet  3 . The introduced specimen rack  4  is carried to a determination section  6  through a buffering section  5  which is formed to prevent the specimen rack  4  sequentially carried from the carrier line  2  from being stuck. A camera  7  is installed in the determination section  6  such that the determination is made through the image processing. The information with respect to the specimen container, for example, height, external diameter, and the plug configuration is preliminarily registered to be compared with the actually processed image of the specimen container so as to make the determination with respect to the height, external diameter and the plug configuration of the specimen container. As the specimen containers (1 to 5) mounted in each specimen rack may be subjected to an image processing simultaneously, the determination time may be markedly shorter than the time for the generally employed determination for each specimen container. 
         [0020]    Identification numbers  13   a  to  13   j,  for example, bar codes are allocated to predetermined positions of the specimen racks  4  respectively to allow the determination with respect to the identification number of the rack simultaneously with the image processing. 
         [0021]    Identification numbers  11   a  to  11   j,  for example, bar codes are also allocated to respective specimen containers  10   a  to  10   j,  which allow determination with respect to the identification numbers of the specimen containers through the image processing. 
         [0022]    The determination section determines with respect to the height and the external diameter of the specimen container, the plug configuration, the presence/absence of the plug, the identification number of the specimen container, and the identification of the specimen rack to determine with respect to the operation for opening the respective specimen containers. 
         [0023]    After performing the determination with respect to the height, the external diameter, the plug configuration, the presence/absence of the plug, the identification number of the specimen container, and the identification of the specimen rack, when the result becomes indeterminable, the error is reported to the host-computer, and the failure specimen rack or the failure specimen container will be carried to a plug opening unit feed section. Then it will be stored in an error specimen rack storage section disposed in the specimen preprocessing system via the carrier line  2 . 
         [0024]    The plug opening operation for the specimen rack  4  determined as having been provided with no plug is skipped. When all the specimen containers  10   a  to  10   j  in the specimen rack  4  are not plugged, they are carried to the conveyor line  2  through a specimen rack outlet  9  and further to the other specimen preprocessing unit. 
         [0025]    The specimen rack  4  determined as being normal is carried to a plug opening position  8 , and allows a specimen container lifting mechanism  14  to grip the specimen container at a predetermined position so as to be lifted to the plug opening position for opening the plug. 
         [0026]    Upon completion of the plug opening operation, the specimen rack  4  is carried to the determination section to allow the camera  7  to process the image again. 
         [0027]    When the plug opening fails, the specimen rack is carried to the plug opening position  8  again by an arbitrary retry number of times for performing the plug opening operation. If the opening operation still fails in spite of the retry arbitrarily set number of times, the error is reported to the host-computer. The specimen rack determined as the error is stored in the error specimen rack storage section disposed in the specimen preprocessing system. 
         [0028]    If the opening operation ends successfully, the rack is carried to the carrier line  2  through the specimen rack outlet  9  of the plug opening unit and further to the other specimen preprocessing unit. 
         [0029]    The flow of the processes of the specimen container lifting mechanism and the plug opening mechanism in the plug opening position  8  will be described referring to  FIGS. 3A and 3B . 
         [0030]    The specimen container lifting mechanism  14  has the stroke for lifting the specimen container  16  different from the one for lifting the specimen container  17  depending on the result of the determination section  6 . The position of the plug opening mechanism is always kept constant. The plug opening operation is simplified by making the lifting stroke variable. 
         [0031]      FIGS. 3A and 3B  show the state where the specimen containers  10   a  to  10   j  each having different height, external diameter and plug configuration are mounted in the specimen rack  4 . The identification numbers  13   a,    13   b  are allocated to predetermined positions of the specimen racks  4 , the identification numbers are also allocated to the respective specimen containers  10   a  to  10   j.  The determination section  6  performs the image processing in the aforementioned state to determine the identification numbers of the specimen rack  4  and the specimen containers, respectively so as to determine with respect to the height, the plug configuration and the external diameter of the respective specimen containers. A height adjustment spacer  18  is disposed at the lower portion of the specimen container. The image processing may be performed to determine with respect to the spacer  18  so as to accurately determine with respect to the specimen containers each with similar height. If the specimen container has a special configuration such as the specimen container  10   f,  the specimen container lifting mechanism  14  sets the grip position of the specimen container above the general level to avoid the plug opening operation failure owing to unstable grip at the tapered portion. 
         [0032]    It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
A specimen preprocessing system including a specimen rack which supports a specimen container with its opening sealed with a plug for storing the specimen, a carrier line for carrying the specimen rack, a preprocessing unit to which the specimen rack is carried by the carrier line, and a control unit for controlling the carrier line and the preprocessing unit is provided with a plug opening unit which is capable of opening plugs of the specimen containers each having a different height (different plug configuration or diameter) mounted in the same specimen rack.