Abstract:
Disclosed herein is a sample-processing system that can improve total system processing efficiency, and reduce a sample-processing time, by establishing a functionally independent relationship between a rack conveyance block with rack supply, conveyance, and recovery functions, and a processing block with sample preprocessing, analysis, and other functions. A buffer unit with random accessibility to multiple racks standing by for processing is combined with each of multiple processing units to form a pair, and the system is constructed to load and unload racks into and from the buffer unit through the rack conveyance block so that one unprocessed rack is loaded into the buffer unit and then upon completion of process steps up to automatic retesting, unloaded from the buffer unit. Functional dependence between any processing unit and a conveyance unit is thus eliminated.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to sample-processing systems. More particularly, the invention relates to a sample-processing system suitable for efficient operation of a plurality of analyzers different in functionality and in processing capabilities and interconnected using a conveyor line to convey sample racks. 
         [0003]    2. Description of the Related Art 
         [0004]    Analytical results on blood plasma, serum, urine, and other biological samples provide large volumes of useful information for diagnosing medical conditions, and there are a large number of conventional techniques relating to analyzers intended for automatic processing of such biological samples. 
         [0005]    JP-A-10-19899, for example, discloses a technique on which is based an automatic analyzer that includes a plurality of analytical units each equipped with transfer means for loading a rack into the analytical unit, with transfer means provided independently of the former transfer means in order to unload the rack from the analytical unit, and with discrimination means provided on the upstream side of the analytical unit in order to discriminate a request item for a sample. The analyzer, after judging which of the multiple analytical units is to be used to analyze the sample, assigns a rack-loading instruction to an appropriate analytical module. 
         [0006]    Also, JP-A-10-213586 describes an automatic analyzer equipped with a plurality of analytical units along a belt conveyor line, with a rack supply unit at one end of the conveyor line, and with a rack recovery unit at the other end of the conveyor line. A standby unit for causing racks to stand by for processing is further disposed in front of the rack recovery unit so as to allow automatic retesting. 
         [0007]    In addition, JP-A-279357 describes an automatic analyzer in which a standby disc for causing racks to stand by for processing is disposed on a rack conveyance route between a rack supply unit and an analytical unit, the standby disc being provided for avoiding congestion on the rack conveyance route and for automatic retesting. 
       SUMMARY OF THE INVENTION 
       [0008]    In the automatic analyzer of JP-A-10-19899, a rack conveyance route is determined before the rack is conveyed to the analytical unit. When analysis by multiple analytical units is required, therefore, since samples will be conveyed in order from the upstream side, if there are a large number of samples to be analyzed on the upstream side, the rack conveyance route will become congested and none of any samples to be analyzed only on the downstream side will be able to move past a sample existing upstream. 
         [0009]    In the automatic analyzer of JP-A-10-213586, although a return route is provided to convey racks from the downstream side to the upstream side, when a rack is conveyed to a downstream analytical unit first, it will be absolutely necessary that the rack, before being conveyed to an upstream analytical unit, be returned to the rack supply unit located at the uppermost position of the upstream side. In addition to consuming time, such a conveying sequence will obstruct the processing of the racks supplied from the supply unit. 
         [0010]    Additionally, the samples that require automatic retest will be concentrated at the standby unit in front of the recovery unit. In a system configuration with a plurality of analytical units each different in processing rate, therefore, even when a rack is present that contains samples whose analytical results have already been output and which are to undergo retests, an unnecessary waiting time will occur since that rack will be unable to pass a rack that has entered the standby unit earlier. Furthermore, for retesting, the rack will need to be returned to the rack supply unit similarly to the above, so the conveying sequence in this case as well will correspondingly consume time and obstruct the processing of the racks supplied from the supply unit. 
         [0011]    In the automatic analyzer of JP-A-279357, although the rack standby unit has circular disc construction and is therefore excellent in random accessibility to racks, a dead space occurs on the disc since the racks themselves are of a general shape close to a rectangle. Also, the dead space in the entire system due to the use of the circular disc is large. 
         [0012]    Additionally, in a system configuration with a plurality of analytical units, since the rack is conveyed to a downstream analytical unit through the standby disc, the direction of the rack becomes inverse and the traveling direction of the rack needs to be returned to its original direction in front of the next analytical unit. 
         [0013]    An object of the present invention is to provide a sample-processing system optimized in terms of total system process flow by assigning only a rack conveyance function to a rack supply unit, a conveying unit, and a recovery unit, as their intended purpose, and assigning all other characteristic and necessary functions of processing units to each of the processing units. 
         [0014]    Among major problems associated with conventional techniques is that the rack conveyance unit has a functional block that the standby unit and other analytical units require. 
         [0015]    A system according to the present invention includes a buffer unit that causes a plurality of racks to stand by for processing and has random accessibility to each rack, and the buffer unit is combined with each of multiple processing units to form a pair. The system is also constructed to load/unload each rack into/from the buffer unit. One unprocessed rack is loaded into the buffer unit and then upon completion of process steps up to automatic retesting, the rack is unloaded from the buffer unit. Functional dependence between any processing unit and a rack conveyance unit is thus eliminated. 
         [0016]    In addition, if a rack transfer block that uses the buffer unit to transfer racks to and from a rack conveyance block is constructed to be able to access both a feed route and return route of the racks conveyed by the rack conveyance unit, minimizing a conveying distance between processing units allows the system to start the earliest executable process first, without being aware of layout order of multiple processing units, even when the kind of processing of a particular sample spans the multiple processing units. This, in turn, makes it unnecessary to determine the entire rack conveyance route on the upstream side of the system. In addition, upon completion of processing in one processing unit, loads of other processing units can be confirmed, so the rack can be conveyed to the processing unit whose load is the lightest of all processing unit loads. A processing time of the entire system is reduced as a result. 
         [0017]    A sample-processing system optimized in terms of total system process flow can be provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a configuration diagram of a sample-processing system according to an embodiment of the present invention; 
           [0019]      FIG. 2  is a functional block diagram of the system configuration of  FIG. 1 ; 
           [0020]      FIG. 3  is a configuration diagram of a sampler unit in the embodiment of the present invention; 
           [0021]      FIG. 4  is a configuration diagram of a load rack-moving mechanism of the sampler unit; 
           [0022]      FIG. 5  is a block diagram of a buffer unit in the embodiment of the present invention; 
           [0023]      FIG. 6  is a block diagram and operational illustrative diagram showing a rack transfer mechanism of the buffer unit; 
           [0024]      FIG. 7  is another block diagram and operational illustrative diagram showing the rack transfer mechanism of the buffer unit; 
           [0025]      FIG. 8  is yet another block diagram and operational illustrative diagram showing the rack transfer mechanism of the buffer unit; 
           [0026]      FIG. 9  is a further block diagram and operational illustrative diagram showing the rack transfer mechanism of the buffer unit; 
           [0027]      FIG. 10  is a further block diagram and operational illustrative diagram showing the rack transfer mechanism of the buffer unit; 
           [0028]      FIG. 11  is a further block diagram and operational illustrative diagram showing the rack transfer mechanism of the buffer unit; 
           [0029]      FIG. 12  is a further block diagram and operational illustrative diagram showing the rack transfer mechanism of the buffer unit; 
           [0030]      FIG. 13  is a further block diagram and operational illustrative diagram showing the rack transfer mechanism of the buffer unit; 
           [0031]      FIG. 14  is a further block diagram and operational illustrative diagram showing the rack transfer mechanism of the buffer unit; 
           [0032]      FIG. 15  is an illustrative diagram of rack conveyance between the buffer unit and a functional module; 
           [0033]      FIG. 16  is an illustrative diagram of rack conveyance between the buffer unit and a supplemental module; 
           [0034]      FIG. 17  is a flowchart of rack conveyance route determination; 
           [0035]      FIG. 18  is an illustrative diagram of the rack flow in the embodiment of the present invention; 
           [0036]      FIG. 19  is another illustrative diagram of the rack flow in the embodiment of the present invention; and 
           [0037]      FIG. 20  is an illustrative diagram of emergency-test sample loading rack flow. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    An embodiment of the present invention will be described hereunder. 
         [0039]      FIG. 1  is a plan view of a sample-processing system according to an embodiment of the present invention. The system shown as an example in  FIG. 1  includes: a sampler unit  100  for loading and storing a sample rack; a rack conveyance unit  200  for conveying the sample rack between the sampler unit and functional modules; buffer units  300   a  and  300   b  each disposed along the rack conveyance unit  200 , for transferring the sample rack to and from the rack conveyance unit  200  and for causing temporary standby of the sample rack; functional modules  400   a  and  400   b  each paired with the buffer unit  300   a  or  300   b  and located to the right thereof; and a supplemental module  500  located to the right of the buffer unit  300   a.    
         [0040]      FIG. 2  shows the system of  FIG. 1  in functionally classified form. In this case, constituent elements of the system can be classified into a functional block  1  including the buffer unit  300   a , the functional module  400   a , and the supplemental module  500  in order to undertake sample analysis, preprocessing, and other processes, a functional block  2  including the buffer unit  300   b  and the functional module  400   b , and a sample rack conveyance block  3  including the sampler unit  100  and the rack conveyance unit  200 . The functional block  1 , the functional block  2 , and the conveyance block  3  deliver and receive sample racks to and from each other at connections  4  and  5 . 
         [0041]    While the functional blocks in the present embodiment are each constructed of a buffer unit and a functional module, a functional module including a buffer unit therein is also embraced in the present invention. 
         [0042]    Also, the functional block  1 , the functional block  2 , and the conveyance block  3  are constructed so that input and output sections required for each will be connected to equipment of related facilities independently of each other. In addition, except for processes relating to the exchange of sample racks between the three blocks, that is, physical movement of each sample rack, issuance of processing requests concerning samples, transmission of results, and exchange of other information, the functional blocks  1 ,  2  and the conveyance block  3  are constructed to be operable in completely independent form. 
         [0043]    Each constituent unit of the system, and total system operation will be described hereunder. 
         [0044]    A configuration of the sampler unit  100  is shown in  FIG. 3 . 
         [0045]    The sampler unit  100  includes: a loader  101  for loading a sample rack into the system; a storage section  102  for unloading sample racks from the system; a load rack moving unit  103  for transferring a loaded sample rack from the loader to the rack conveyance unit  200 ; a rack ID reading unit  104  for reading identification (ID) information assigned to the sample rack; a sample vessel height detection unit  105  for confirming whether sample vessels are set up on the sample rack, and detecting height of each sample vessel; a sample ID reading unit  106  for reading, for example, an ID label of the sample, affixed to the sample vessel set up on the sample rack; a sample vessel rotating unit  107  for rotating the sample vessel during the reading of the sample ID; an unload rack moving unit  108  for moving the rack from the rack conveyance unit  200  to the storage section  102 ; an emergency-test sample loader  109  for loading an emergency-test sample rack into the sample-processing system or for loading thereinto a sample rack conveyed from a rack conveyance system connected on the upstream side of the sample-processing system; and a rack unloader  110  for unloading the sample rack into the rack conveyance system connected on the upstream side of the sample-processing system. 
         [0046]    The loader  101  includes a loading tray setup unit  121  in which to set up a sample rack tray capable of being hand-carried with a plurality of sample racks set up thereon, and a loading buffer  122  disposed between the tray setup unit and the load rack moving unit  103 . The loader  101  also has a loading lever  123  functioning as a driving mechanism to convey the sample racks in a Y-direction. In addition, the loader  101  has a loading mechanism  124  (see  FIG. 4 ) that is adapted to rotate the loading lever axially in the Y-direction. 
         [0047]    After a sample rack tray has been set up in the loading tray setup unit  121 , the loading mechanism  124  activates a rotating motor  125  to rotate the loading lever  123 , and drives a moving motor  126  to move the sample rack tray in the Y-direction. The sample racks on the tray are thus conveyed to the load rack-moving unit  103  through the loading buffer  122 . After all racks have moved out from the loading buffer  122 , the loading mechanism  124  rotates the loading lever  123 . The lever then returns to a required sample rack tray setup position and stands by for the next sample rack tray to be set up thereat. 
         [0048]    Upon completion of the movement of all sample racks from the sample rack tray to the loading buffer  122 , the sample rack tray is removable, thus allowing setup of the next sample rack tray. In this case, after moving out all racks from the loading buffer  122 , the loading lever  123  of the loading mechanism  124  usually conducts a rack-loading process upon the sample rack tray that has been newly set up in place. Instead, however, the loading process for the sample racks in the loading buffer  122  can be interrupted using a switch (not shown) that is provided on the sampler unit  100 , or in accordance with an operator instruction from a screen of an operating unit. After the interruption, the loading lever  123  can be returned to the load tray setup position  121  in order to restart the feed operation for the racks on the sample rack tray. 
         [0049]    In addition, the present embodiment has two sample-loading units, and when the rack feed operation by one of the units is completed and all racks are gone from the particular unit, the other unit conducts a rack feed operation. While the present embodiment has two sample-loading units, processing in an arrangement of more than two units also advances similarly. 
         [0050]    After receiving the rack from the loading unit, the load rack moving unit  103  transfers the rack to the rack ID reading unit  104 , by which the ID of the rack is then read and the rack is further transferred to the sample vessel height detection unit  105 . 
         [0051]    The sample vessel height detection unit  105  confirms whether sample vessels are set up in internal positions of the sample rack, and detects the height of each sample vessel. 
         [0052]    After this, the sample rack is moved to a sample ID reading position, at which the IDs of each sample are then read by the sample ID reading unit  106 . A sample-vessel rotating unit  107  is equipped at the sample ID reading position. 
         [0053]    In general, bar codes are used as sample IDs. Also, cups, test tubes, test tubes each with a cup thereupon, or other various kinds of objects are used as sample vessels. The bar codes as sample IDs, because of a dimensional requirement for each to have a necessary amount of information, are usually labeled onto test tubes only. During the processing of samples, therefore, whether the sample ID is to be read and whether the sample vessel is to be rotated are judged from the foregoing rack ID information and sample vessel height information. 
         [0054]    Necessary processes for the sample rack are determined from the above rack ID and sample ID information. Also, functional modules are determined as conveyance destinations. 
         [0055]    After the conveyance destinations of the sample rack have been determined, the load rack-moving unit  103  moves the rack to the rack conveyance unit  200 . 
         [0056]    An emergency-test sample rack or a sample conveyance system connected on the upstream side of the sampler unit  100  is loaded from the emergency-test sample loader  109  into the sampler unit. The rack that has been loaded from the emergency-test sample loader  109  undergoes substantially the same kind of processing as that of the above-described rack loaded from the sample loader  101 , and then moves to the rack conveyance unit  200 . 
         [0057]    Also, the sample rack that has gone through the necessary processes in each functional module is moved to the storage section  102  by the unload rack moving unit  108 . 
         [0058]    As with the loader  101 , the storage section  102  includes an unloading tray setup unit  131  in which to set up a sample rack tray capable of being hand-carried with a plurality of sample racks set up thereon, and an unloading buffer  132  disposed between the loading tray setup unit and the load rack moving unit  103 . An unloading lever  133  for conveying the sample racks in a Y-direction is also equipped as a driving mechanism. 
         [0059]    The sample racks that have been conveyed to a front area of the storage section  102  by the unload rack moving unit  108  are conveyed to the unloading buffer  132  through a load rack moving lane by the unloading lever  133 , and when the unloading buffer  132  is filled with as many sample racks as mountable on one sample rack tray, the racks are each moved to the tray. 
         [0060]    Instead, the sample racks in the unloading buffer  132  can be moved to the sample rack tray in the unloading tray setup unit  131  by operating a switch (not shown) that is provided on the sampler unit  100 , or by sending an operator instruction from a screen of an operating unit (not shown). 
         [0061]    The sample-processing system further has the rack unloader  110  for unloading a sample rack into the sample conveyance system connected on the upstream-side of the sample-processing system. The rack unloader  110  is of a size adapted for holding one rack, and is also constructed to be slidable in a Y-direction so that a position for Y-axial unloading of the rack into the sample conveyance system can be changed. 
         [0062]    The rack conveyance unit  200  in  FIG. 1  has two rack conveyance lanes, namely, a feed lane  201  for conveying sample racks from the sampler unit  100  to the functional modules  400   a ,  400   b , and a return lane  202  for conveying the sample racks from the functional modules  400   a ,  400   b  to the sampler unit  100 . The rack conveyance unit  200  also has a belt mechanism  210 , a stopper mechanism  220 , and a shutter mechanism  230 , as shown in  FIG. 5 . 
         [0063]    The belt mechanism  210  uses conveyor belts to convey the sample racks between the sampler unit  100  and the functional modules  400   a ,  400   b , along the feed lane  201  and the return lane  202 . In the present embodiment, one conveyor belt is used for the feed lane and the return lane each, and a conveyor belt-driving motor  211  and a belt-tensioning mechanism  212  are equipped at a terminatory section of the rack conveyance unit  200 . This scheme allows rapid sample rack conveyance. Also, this scheme is suitable for a system with a random-conveyance ability to convey sample racks to a plurality of functional modules or bi-directionally between the functional modules arranged on the upstream and downstream sides of the system. Although no description is given in the present embodiment, this scheme may be suitable for a processing system in which, as in a sample preprocessing system, the same sample rack stops at a plurality of functional modules, for example, centrifuging, decapping, and pipetting modules in order from the upstream side of the system to the downstream side to undergo processing. In that case, a plurality of conveyor belts with a length equal to width of each functional module are arranged in series, and during processing, the sample rack is delivered and received between adjacent conveyor belts. It is desirable, therefore, that an appropriate mechanical configuration of belts be selectable to suit a particular configuration of the system and necessary processing capabilities thereof. 
         [0064]    The stopper mechanism  220  for stopping the sample rack at predetermined positions on sample rack loading routes to each functional module has a stopper  220   a  for the feed lane  201  and a stopper  220   b  for the return lane  202 . 
         [0065]    The shutter mechanism  230  has a total of three vertically movable rack guide plates, two for rack guiding on the feed lane  201  and one for rack guiding on the return lane  202 , and moves downward only for sample rack unloading into each functional module or for sample rack loading therefrom. 
         [0066]    A configuration of a buffer unit  300  is shown in  FIG. 5 . 
         [0067]    The buffer unit  300  including a rack-unloading standby section  301 , a buffer  302 , a cold-storage section  303 , a module loading/unloading standby position  304 , a rack conveyance section  310 , a one-rack loader/unloader  320 , and an ID reader  321 , moves the sample rack via rack-unloading mechanisms  370  and  371 . 
         [0068]    The rack-unloading standby section  301  is a position having a space for causing one rack to stand by, and at this standby position, the sample rack from the rack conveyance unit  200  is transferred to the buffer unit  300 . This standby position is also where a sample rack to be unloaded from the buffer unit  300  into the rack conveyance unit  200  is made to stand by. 
         [0069]    The buffer  302  further includes a plurality of independent slots in each of which a sample rack can be made to stand by temporarily. 
         [0070]    The cold-storage section  303  is constructed so that a plurality of sample racks, each containing accuracy management samples or other samples that require periodic processing in the functional modules, can be made to stand by inside. The cold-storage section  303  has a cold-storage function to prevent these samples from evaporating. 
         [0071]    The module loading/unloading standby section  304  is a position having a space for causing one rack to stand by, and at this standby position, the sample rack from the buffer unit  300  is unloaded into the functional module  400 . This standby position is also where a sample rack that has undergone processing in the functional module is loaded into the buffer unit  300 . 
         [0072]    The rack conveyance section  310  conveys the sample rack between the module loading/unloading standby position  304  and the functional module  400 . 
         [0073]    The one-rack loader/unloader  320  functions as a sample loader/unloader for processing the sample rack in the functional module without involving the rack conveyance unit  200 . 
         [0074]    A rack transfer mechanism  330  transfers the sample rack bi-directionally in a Y-direction between the rack loading/unloading standby section  301  and the feed lane  201  of the rack conveyance unit  200 , and between the rack loading/unloading standby section  301  and the return lane  202 . For sample rack transfer in one direction only, the sample rack can usually be moved horizontally if the rack conveyance surface height existing after the rack has been moved is adjusted to be slightly smaller than the rack conveyance surface height existing before the rack is moved. In the present system, however, the transfer mechanism  330  also needs to have a function that lifts the rack in a Z-direction, because bi-directional movement is required and because the rack needs to cross the feed lane  201  to move to and/or from the return lane  202 . 
         [0075]    The rack transfer mechanisms  330  are further detailed below using  FIGS. 6 to 10 . Rack transfer from the feed lane  201  of the rack conveyance line  200  to the rack loading/unloading standby section  301  is taken as an example in the description. 
         [0076]    The rack transfer mechanism  330  includes a gripper  340  and a Y-mover  350 . The gripper  340  has a function that opens/closes two gripping plates in a Y-direction to grip the rack, and a function that lifts the gripped rack in a Z-direction. The Y-mover  350  moves the gripper in the Y-direction. 
         [0077]    The gripper  340  includes a pulley  343  that transmits driving force using a motor  341  and a belt  342 , a rotating shaft  344  of the pulley, two gripping plates  346  fitted with cam followers  345  and movable vertically in the Z-direction, and a spring  347  that works in a direction to draw the gripping plates  346  closer to the spring. Also, the pulley  343  has two bearings  348  and the rotating shaft  344  of the pulley has a stepped cam  349 . 
         [0078]    The buffer unit  300  activates a driving motor  351  of the Y-mover  350  in the rack transfer mechanism  330 , thus moving the gripper  340  to the feed lane  201  of the rack conveyance line  200  in order to load a sample rack. At this time, the gripper  340  is in an open condition, that is, with the two gripping plates  346  pushed open by the two bearings  348  fitted in the pulley  343 , and with the cam followers  345  and the cam  349  not in contact with each other. 
         [0079]    The rack conveyance unit  200  drives the stopper  220   a  disposed at the rack transfer position in the buffer unit  300 , and protrudes the stopper above the feed lane  201 . After this, the rack conveyance unit  200  drives a motor  211   a  of the belt mechanism  210  and moves the sample rack. 
         [0080]    The gripper  340  rotates the pulley  343  by driving the motor  341  to grip the sample rack that has stopped at the transfer position. The rotation of the gripper moves the bearings  348 , closes the two gripping plates  346  in the Y-direction by the pulling force of the spring  347 , and grips the sample rack, as shown in  FIG. 7 . Further rotation of the motor  341  brings the bearings  348  into a non-contact state with respect to the gripping plates  346 , thus moving the cam followers  345  onto an elevated section of the cam, as shown in  FIG. 8 , and consequently moving the two gripping plates  346  upward to allow rack lifting in the Z-direction. 
         [0081]    After the gripper  340  has lifted the sample rack in the Z-direction, the rack conveyance unit  200  drives a motor of the shutter  230  and moves the shutter  231  downward. 
         [0082]    After the shutter  231  has moved downward, the rack transfer mechanism  330  drives the motor  351  of the Y-mover and moves the sample rack in the Y-direction for transfer to the rack loading/unloading standby section  301 . 
         [0083]    Upon completion of the sample rack transfer, the rack conveyance unit  200  returns the stopper  220   a  from the feed lane and moves the shutter  230  upward for the next sample rack transfer. 
         [0084]    After the movement of the sample rack to the rack loading/unloading standby section  301 , the gripper  340  releases the gripped condition of the sample rack. This operation is conducted by rotating the motor  341  in an inverse direction relative to the rotating direction for gripping the rack, and the release is conducted in order reverse to that of gripping. 
         [0085]    While the gripper in the present embodiment is constructed to lift the sample rack in operational association with the opening/closing operation of the gripping plates by driving one motor, substantially the same effect can be obtained by providing an independent motor for the gripping plate opening/closing operation and the rack-lifting operation each. 
         [0086]    A rack-moving mechanism  360  includes a bucket  361  adapted to hold one rack and move in the Y-direction, an X-mover  36  that moves in the Y-direction with the bucket to move the internal rack thereof in an X-direction, and a vertically movable carriage  363  installed in the X-mover  36 . 
         [0087]    The rack-moving mechanisms are further detailed below using  FIGS. 11 to 14  with the sample rack transfer from the rack loading/unloading standby section  301  to the buffer  302  taken as an example in the description. 
         [0088]    First, the rack-moving mechanism  360  drives a Y-driving motor  364  to move the bucket  361  to the position of the rack loading/unloading standby section  301 , as shown in  FIG. 11 . At the same time, the rack-moving mechanism  360  also drives an X-driving motor  365  to move the carriage  363  of the X-mover  362  to a position under the sample rack in the rack loading/unloading standby section  301 , and after the carriage  363  has moved to a position at which the carriage gets into a bottom groove of the sample rack, moves a Z-driving motor  366  to move the carriage upward, as shown in  FIG. 12 . 
         [0089]    The bucket  361  and a sample rack conveyance surface of the rack loading/unloading standby section  301  both have a slit  367  to make the carriage  363  movable in an upward moved condition in the X-direction. A like slit is also provided in the buffer  302 , the cold-storage section  303 , and other sections using the rack-moving mechanism  360  to move the sample rack. 
         [0090]    Next, the rack-moving mechanism  360  moves the carriage  363  under the bucket  361  by driving the X-driving motor  365  to move the sample rack to the bucket, as shown in  FIG. 13 . 
         [0091]    After the sample rack has been moved to the bucket  361 , the rack-moving mechanism  360  drives the Y-driving motor  364  to move the bucket  361  to a destination slot in the buffer  302 . At this time, the carriage  363  remains in an upward position to prevent the rack in the bucket from moving in the X-direction and sliding out from the bucket. 
         [0092]    After the bucket has moved to the slot in the buffer  302 , the rack-moving mechanism  360  moves the carriage  363  under the slot by driving the X-driving motor  365  to move the sample rack to the slot, as shown in  FIG. 14 . 
         [0093]    In the present embodiment, rack movement from the rack loading/unloading standby section  301  to the bucket  361  has been described. Sample racks are also moved from other sections such as the buffer  302  or cold-storage section  303  to the bucket  361  in essentially the same manner. In addition, while rack movement from the bucket  361  to the buffer  302  has been described, sample racks are moved to the cold-storage section  303 , the module loading/unloading standby position  304 , and other sections, in essentially the same manner. Constructing other sections so as to have independent standby slots for sample racks allows random accessing of any rack. 
         [0094]    Next, transferring a sample rack from the buffer unit  300  to the functional module  400  is described below using  FIG. 15 . 
         [0095]    The sample rack transferred to the functional module  400  is moved to the module loading/unloading standby position  304  by the rack-moving mechanism  360 , and further moved to the rack conveyance section  310  by the rack-unloading mechanism  370 . 
         [0096]    The rack conveyance section  310  takes a mechanical configuration suitable for the functional module involved. An example in which the functional module  400  is of a type that draws the sample rack from the rack conveyance section into the functional module and after execution of a necessary process such as pipetting, returns the sample rack to the rack conveyance section, is described in the present embodiment. Also, the functional module in the embodiment has a buffer capable of holding a plurality of racks in series inside. 
         [0097]    The sample rack that has been moved to the rack conveyance section  310  by the rack-unloading mechanism  370  is moved on to a sample rack loading position  401  in the functional module by the rack-moving mechanism. The rack-moving mechanism here can be a belt mechanism such as the rack conveyance line  200 , or can be a mechanism such as the carriage. 
         [0098]    The sample rack that has been drawn into the functional module  400  by a rack-loading mechanism thereof (not shown) is moved to a processing position  402  to undergo the necessary process such as pipetting. During this process, if a following sample rack to be processed in the functional module  400  is present, the buffer unit  300  moves the sample rack to the functional module via the rack conveyance section in essentially the same sequence. The functional module then causes the sample rack to stand by at a buffer position  403  in the module. 
         [0099]    After being processed in the functional module  400 , the sample rack is once again returned to a rack-unloading position  404  on the rack conveyance section  310  by a rack-unloading mechanism not shown. The rack-moving mechanism moves the sample rack in a direction inverse to that of the transfer of the rack to the functional module  400 , thus unloading the rack into the module loading/unloading standby position  304 . 
         [0100]    In the present embodiment, sample racks move bi-directionally between the buffer unit  300  and the rack conveyance section  310 , and rack loading/unloading to/from the buffer unit  300  is controlled according to the number of racks which can be held in the buffer of the functional module  400 . In other words, sample rack unloading from the buffer unit  300  is continued until the buffer of the functional module  400  has become full, but after the buffer has become full, the sample rack returned from the functional module  400  will be loaded into the buffer unit  300 , so the module loading/unloading standby position  304  is left empty and after the sample rack from the functional module  400  has moved inside the buffer unit  300 , the next sample rack is moved to the module loading/unloading standby position  304  and conveyed to the functional module  400  via the rack conveyance section  310 . 
         [0101]    An example in which the functional module internally has a buffer function to hold a plurality of racks in series with respect to the processing position has been described in the present embodiment. However, essentially the same processing results can be achieved by, for example, using either a functional module of a type to and from which the sample rack can be loaded and unloaded at the same position in the module, or a functional module of a type in which the necessary process such as pipetting can be conducted on the conveyance line without involving rack loading/unloading. In that case, although the mechanical configuration of the rack conveyance section  310  requires a change, there is no need to change the buffer unit  300  or the rack conveyance logic. 
         [0102]    Next, conveying a rack from the buffer unit  300  to the supplemental module  500  is described below using  FIG. 16 . The supplemental module  500  in the present embodiment is disposed on the left side of the buffer unit  300  and has independent sample rack loading and unloading positions. 
         [0103]    A sample rack to be unloaded into the supplemental module  500  is moved to the bucket  361  of the rack-moving mechanism  360 , and then further moved to a rack-unloading position  501  in the supplemental module  500  by rotational driving of the Y-driving motor  364  of the rack-moving mechanism  360 . After that, the rack-unloading mechanism  371  unloads the sample rack within the bucket  361  onto the conveyance line of the supplemental module by pushing out the rack. 
         [0104]    The sample rack that has been carried into the supplemental module is provided with the necessary process, such as pipetting, at the processing position  502  and then moved to a rack unloading standby position  503  on the conveyance line. 
         [0105]    At a sample rack unloading request from the rack unloading standby position  503 , the rack-moving mechanism  360  of the buffer unit  300  moves the bucket  361  to the rack unloading position  503  in the supplemental module by driving the Y-driving motor  364 . A rack-unloading mechanism  504  of the supplemental module moves the sample rack to the bucket  361  after that. 
         [0106]    Next, the conveyance of a sample rack which has been loaded from the one-rack loader/unloader  320  is described below. 
         [0107]    Upon setup of a sample rack in the one-rack loader/unloader  320  by an operator, the rack-moving mechanism  360  drives the Y-driving motor  364  to move the bucket  361  to the one-rack loading/unloading position  320 , and drives the X-driving motor  365  to move the carriage  363  upward to the position of the sample rack. After this, the sample rack is moved to the ID reading unit  372 , by which the rack ID is then read. This is followed by movement of the sample rack to a sample vessel detector  373  for sample vessel detection and sample ID reading. Data items of processing in the functional module are determined from the rack ID and sample ID information that has been read. The sample rack that has gone through sample ID reading is moved to the bucket  361 , then conveyed to the functional module and the supplemental module in accordance with the above-described conveying sequence, and undergoes processing. The sample rack thus processed is unloaded into the one-rack loader/unloader  320  via the bucket  361  in essentially the same manner as that described above. This completes the conveyance of the rack. 
         [0108]    Even if the sampler unit  100  or the rack conveyance line  200  becomes inoperable for reasons such as a failure, processing in the functional module can be achieved by providing a sample rack loader/unloader such as the one-rack loader/unloader  320  shown in the present embodiment, and as described earlier in this Specification, adopting a configuration with independent supply lines for electric power, pure water, and other utilities. In addition, sample racks standing by in the buffer  302  of the buffer unit  300 , for example, can be unloaded from the one-rack loader/unloader  320  if the operator sends an unloading instruction from a switch or operating unit not shown. 
         [0109]    Next, the cold-storage section  303  in which to make accuracy management samples stand by for processing is described below. 
         [0110]    Accuracy management samples are samples whose data measurements are predetermined to verify validity or correctness of the measurement results obtained during analysis with the analyzer. Stability of the apparatus is confirmed by such verification. Accuracy management samples are measured for each of analytical items periodically, that is, at previously set intervals of time. 
         [0111]    After being loaded from the sampler unit  100 , a sample rack with accuracy management samples set up therein is transferred to the buffer unit  300  by the rack transfer mechanism  330  thereof. The process flow up to this step is substantially the same as the above. 
         [0112]    When the accuracy management sample rack that has been loaded into the buffer unit  300  requires immediate analysis, the sample rack is transferred to the functional module  400  and the samples are analyzed. When immediate analysis is not required or after each sample has been analyzed in the functional module  400 , the accuracy management sample rack is conveyed to the cold-storage section  303  for standby. 
         [0113]    Since the accuracy management samples have predetermined data measurements as described above, natural evaporation of these samples during prolonged standby in the analyzer causes changes in the data measurements. For this reason, the cold-storage section  303  has a cold-storage function to suppress the evaporation of the samples. 
         [0114]    After a fixed time of analysis of a general-test sample, upon an arrival at a time preset to measure an accuracy management sample for a particular item, the accuracy management sample rack standing by in the cold-storage section  303  is conveyed therefrom to the functional module  400  and the accuracy management sample is analyzed. After the analysis, the rack is reconveyed to the cold-storage section  303 , in which the rack then waits for a request for measurement of the next accuracy management sample. 
         [0115]    The accuracy management sample rack standing by in the cold-storage section  303  is unloaded therefrom under an operator instruction from the operating unit and then stored into the storage section  102  of the buffer unit  100  through the return lane  202  of the rack conveyance unit  200 . 
         [0116]    Next, total system operation is described below. 
         [0117]      FIG. 17  is a flowchart showing a method of determining sample rack conveyance routes. 
         [0118]    Sample rack conveyance routes are determined upon completion of ID recognition with the rack ID reading unit  104  and sample ID reading unit  106  of the sampler unit  100 , upon the unloading of the sample rack into the module rack-unloading position  404  of the buffer unit  300  following completion of processing in the functional module, and upon completion of ID recognition by the ID reader  321  provided to read the sample rack that has been loaded from the one-rack loader/unloader  320 . 
         [0119]    A system control unit not shown manages load information on the functional modules that form part of the system, that is, the number of samples and analytical items to undergo processing in each functional module. The system control unit also searches in the above timing for the functional module whose load is the lightest of all module loads. In addition, the system control unit searches for items processable in the functional module. The load here includes processing capabilities of each functional module as well as the number of items to be processed in each functional module, and is based upon, for example, a time up to completion of a preassigned task by the functional module, that is, the time arithmetically derived by multiplying the number of processable items by the time required for execution of the particular process. 
         [0120]    The control unit judges whether an extracted functional module can conduct the necessary process for the rack. If the process in the extracted functional module is necessary, this module is determined as a destination to which the rack is to be moved, and the rack is conveyed to the destination. 
         [0121]    If, as a result of the module search, a plurality of functional modules identical in load are present and the process for the rack is to be conducted in each of these modules, the functional module nearest to a current position of the rack is determined as the destination thereof. 
         [0122]    If the process in the functional module which has been extracted because of the lightest load is unnecessary, the control unit searches for the functional module of the next lowest load, and for items processable in this module, and judges once again whether the necessary process can be conducted for the rack. This sequence is repeated for all functional modules and whether each module can be a destination for the rack. 
         [0123]    If none of the functional modules is eventually found to be fit for use as the destination of the rack, the control unit judges whether the rack requires automatic retesting. If automatic retesting is required, the rack is moved to the buffer of the buffer unit and waits for analytical results to be output. After the output of the analytical results, if retesting is necessary, the rack is reconveyed from the buffer to the processing position in the functional module. After being processed, the rack is unloaded from the buffer unit and stored into the storage section of the sampler unit through the return lane of the rack conveyance section. If automatic retesting is unnecessary or if automatic retesting, although it has once been judged to be necessary and the rack has been placed in the buffer for standby, is newly judged from output results not to be necessary, the rack is stored from the buffer unit into the storage section similarly to the above. 
         [0124]    Load information on each functional module is updated upon detection of a change in load, that is, upon the determination of a new destination for the sample rack, or upon the unloading thereof into the module rack-unloading position of the buffer unit following an end of the process in the functional module. 
         [0125]    Examples of actual sample rack flow are described below.  FIGS. 18 and 19  are schematic diagrams of a system which includes a sampler unit  100 , a rack conveyance line  200 , buffer units  300   a ,  300   b ,  300   c , functional modules  400   a ,  400   b ,  400   c , and a supplemental module  500 . 
         [0126]    A case in which a sample rack requires no processing in the functional module  400   a  and the supplemental module  500 , a load upon the functional module  400   a  is the lightest of all loads upon the functional modules  400   a ,  400   b ,  400   c  and the supplemental module  500 , and automatic retesting is unnecessary, is described as an example below using  FIG. 18 . 
         [0127]    In this case, processing items on the sample rack loaded into the sampler unit  100  are determined from the corresponding rack ID and sample ID information in the same manner as that described above. During the determination, the control unit searches for the functional module with the lightest load, and for items processable in this functional module. The functional module  400   a  is determined as a conveyance destination since the module  400   a  is first extracted on the basis of its load information and since the rack requires processing in the module  400   a . In accordance with the determination, the sample rack is transferred from a rack loading/unloading position  203   a  through the feed lane  201  of the rack conveyance unit  200  to the buffer unit  300   a.    
         [0128]    At this time, if the functional module  400   a  to which the sample rack has been transferred is ready to immediately process the rack, that is, if an internal buffer  403   a  of the module  400   a  is not full, the rack is conveyed to the module  400   a . If the functional module  400   a  is not ready for immediate rack processing, the sample rack is conveyed to a buffer  302   a.    
         [0129]    After the sample rack has moved to the buffer unit  300   a , a conveyance route of the next sample rack loaded from the sampler unit is determined in substantially the same manner as that described above. When the functional module  400   a  is determined as the conveyance destination of the next sample rack for substantially the same reason as the above, if the total number of sample racks present in and between the buffer unit  300   a  and functional module  400   a  or supplemental module  500  on the conveyance route at that time is less than the number of slots in the buffer  302   a  of the buffer unit  300   a , the loading of the next sample rack into the buffer unit  300   a  is continued and the sample rack is made to stand by in an empty slot of the buffer  302   a . If the total number of sample racks is equal to the number of slots in the buffer, the sample rack is made to stand by in the sampler unit until sample rack unloading from the buffer unit  300   a  into the conveyance unit  200  has been completed. 
         [0130]    When a vacancy occurs in the buffer  403   a  of the module  400   a , the sample rack that has been made to stand by in the buffer  302   a  is conveyed to functional modules, sequentially processed in each of the modules, and unloaded into a module rack-unloading position  404   a  of the buffer unit  300   a . At this point of time, the next conveyance route is determined for the rack. If the loads of the functional module  300   b , the supplemental module  500 , and the functional module  300   c  are lighter in that order, the control unit extracts the functional module  300   b . However, since the rack requires no processing in  300   b , the control unit next extracts the supplemental module  500  whose load is lighter than that of  300   b . Since the rack requires processing in the supplemental module  500 , this module is determined as the next conveyance destination. 
         [0131]    At this time, if the supplemental module  500  is ready for immediate rack processing, the rack is conveyed directly to the supplemental module  500 . If the supplemental module is not ready for immediate processing, the sample rack stands by in the buffer  302   a  and after the supplemental module has become ready, the rack is conveyed to the module. 
         [0132]    The rack that has gone through the process in the supplemental module  500  is unloaded into the rack-unloading position  503  thereof. This is followed by the next conveyance routing. Since all necessary processing of the rack is already completed, however, the storage section  102  of the sampler unit  100  is determined as the next conveyance destination. In accordance with the determination, the buffer unit  200  activates the transfer mechanism to move the sample rack to the rack loading/unloading position  204   a  on the return lane  202  of the rack conveyance unit  200 , and then the rack conveyance unit  200  stores the rack into the storage section. 
         [0133]    A case in which a sample rack requires processing in the functional modules  400   a ,  400   b ,  400   c , the load of the functional module  400   c  is the lightest of all loads upon each functional module and the supplemental module  500 , and automatic retesting in the functional module  400   b  is necessary, is described as another example below using  FIG. 19 . 
         [0134]    In accordance with the flowchart of  FIG. 17 , the functional module  400   c  with the lightest load is determined as a first conveyance destination for the sample rack which has been loaded into the sampler unit  100 . The loaded sample rack is moved to the rack loading/unloading position  203   c , along the feed lane  201  of the rack conveyance unit  200 , and after the rack has undergone processing in the functional module  400   c  via the buffer unit  300   c , the next conveyance route is determined at the rack unloading position  404   c  of the module. 
         [0135]    If the loads of the functional modules  400   a  and  400   b  at this point of time are the same, the functional module  400   b  nearest to the functional module  400   c  is determined as the next conveyance destination of the sample rack. Therefore, the rack is unloaded into a rack loading/unloading position  204   c  on the return lane  202  of the rack conveyance unit  200  via the buffer unit  300   c , then moved to the rack loading/unloading position  204   b  in the buffer unit  300   b  through the return lane  202 , and processed in the functional module  400   b  via the buffer unit  300   b . After rack processing, the next conveyance route is determined at the rack-unloading position  404   b  of the module. 
         [0136]    If the load of the functional module  400   a  is the lightest of all module loads at this time, the module  400   a  is determined as the conveyance destination for the same reason as described above. The rack is unloaded into the rack loading/unloading position  204   b  on the return lane  202  of the rack conveyance unit  200  via the buffer unit  300   b , then moved to the rack loading/unloading position  204   a  in the buffer unit  300   a  through the return lane  202 , and processed in the functional module  400   a  via the buffer unit  300   a . After rack processing, the next conveyance route is determined at the rack-unloading position  404   a  of the module. 
         [0137]    At this time, a conveyance destination is extracted in accordance with the flowchart of  FIG. 17 . If, at this time, initial measurement results are already obtained in the functional module  400   b  and indicate that retesting is necessary, the functional module  400   b  is determined as the conveyance destination. Conversely if initial measurement results are not obtained and it is unknown whether retesting is necessary, the rack stands by in the buffer  302   a  of the buffer unit  300   a.    
         [0138]    If retesting is necessary, the rack is unloaded into the rack loading/unloading position  203   a  on the feed lane  201  of the rack conveyance unit  200  via the buffer unit  300   a , then moved to the rack loading/unloading position  203   b  in the buffer unit  300   b  through the feed lane  201 , and retested in the functional module  400   b . The retesting of the rack is followed by the next conveyance routing at the module rack-unloading position  404   b.    
         [0139]    At this time, the next conveyance destination is extracted in accordance with the flowchart of  FIG. 17 . Since all processing required for the rack is already completed, the storage section  102  of the sampler unit  100  is determined as the next conveyance destination. Therefore, the rack is unloaded into the rack loading/unloading position  204   b  on the return lane  202  of the rack conveyance unit  200  through the buffer unit  300   b , and stored into the storage section  102  of the sampler unit  100  through the feed lane  202 . 
         [0140]    Conversely if retesting is not required, the storage section  102  of the sampler unit  100  is determined as the conveyance destination of the rack which has been standing by in the buffer  302   a  of the buffer unit  300   a . After this, the rack is unloaded into the rack loading/unloading position  204   a  on the return lane  202  of the rack conveyance unit  200  via the buffer unit  300   b , and stored into the storage section  102  of the sampler unit  100  through the feed lane  201 . 
         [0141]    Next, process flow relating to a loaded emergency-test sample is described below using  FIG. 20 . For simplicity, the description assumes that the emergency-test sample requires processing by the functional module  400   a  only. 
         [0142]    The ID of the emergency-test sample rack  553  which has been loaded into the emergency-test sample loader  109  of the sampler unit  100  is read, then the functional module  400   a  is determined as a conveyance destination, and the rack is loaded from the rack loading/unloading position  203   a  of the buffer unit  300   a  into a rack loading/unloading position  301   a  of the buffer unit  300   a . Upon recognizing that the emergency-test sample will soon be loaded, the buffer unit  300   a  and the functional module  400   a  start operating to move a general-test sample rack  550 ,  551 , or  552  from the conveyance route to the buffer  302   a . When the conveyance route to the functional module  400   a  becomes useable, the emergency-test sample rack  553  is immediately conveyed thereto for processing. Upon the conveyance of the emergency-test sample rack  553  to the functional module  400   a , the general-test sample rack  550 ,  551 ,  552  is reconveyed thereto and processing is restarted. The emergency-test sample rack  553  whose processing has ended is stored into the storage section  102  in accordance with the flowchart of  FIG. 17 .