Abstract:
An automated analyzer for analyzing a specific component in a specimen includes a rotor, a specimen dispenser, a temperature controlling element, a stirrer, and a data analyzer. The rotor is provided with a plurality of specimen container holders for holding the specimen container containing the specimen, and a plurality of reaction container holders that correspond with each of the specimen container holders and hold the sealed reaction containers containing the reagent for reacting with the specimen. The specimen dispenser removes the specimen from the specimen container and dispenses the specimen into the reaction container. The temperature controlling element maintains the temperatures of the reaction container at a constant temperature. The stirrer uses magnetic force to stir a mixed solution of the reagent and the specimen in the reaction container. The data analyzer analyzes the mixed solution.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for automatically analyzing trace components contained in biological samples (specimens) such as blood, serum, plasma or urine, and more particularly to an automated analyzer for analyzing the trace components in such specimens either biochemically or immunologically. 
     2. Description of the Related Art 
     In the field of clinical diagnosis, the use of analyzers for detecting specific components in a specimen collected from a subject and determining the concentration thereof, and then making a diagnosis of an illness or disease based on the results of this analysis has become widespread. These analyzers include multichannel biochemical analyzers which use enzyme reactions and other chemical reactions to analyze sugars, fats, proteins, and the like, and multichannel immunochemical analyzers that use specific interactions between antigens and antibodies to analyze hormones, tumor markers, and the like. 
     In order to avoid contamination among the specimens or the reaction fluids, some of these analyzers conduct the biochemical reactions or immunoreactions in individual disposable reaction containers, and in analyzers which use reaction containers that have been pre-filled with the reagents required for analyzing the specified components in the specimen, the use of disposable reaction containers is normal practice. 
     One example of a known analytical method is enzyme immunoassay (EIA) in which operations are conducted using enzyme labeled antibodies (or antigens). One specific example is known as a sandwich method, in which an antibody (or an antigen), for a specific component to be analyzed, immobilized in a suitable solid phase is used to capture the specific component, an enzyme labeled antibody or antigen (conjugate) is brought in contact to form an immunoreaction complex, any conjugate is removed (by BF separation), and a substrate which utilizes the activity of the enzyme to generate a measurable signal (for example, a variation in light absorbance or a variation in fluorescent intensity) is added. The resulting signal is then measured, the quantity of the enzyme is determined from a prepared calibration curve delineating the relationship between the signal intensity and the enzyme quantity, and this measured enzyme quantity is used to determine the quantity of the specific component being analyzed (see Japanese Patent No. 2,881,826). 
     In this type of EIA, a variety of different reagents, namely antibodies or antigens, must be used depending on the specific component to be analyzed, and consequently reaction containers containing each of the various reagents and sealed with a sealing member (hereafter described as “reagent cups”) are prepared in advance for each specific component, and the appropriate sealed reagent cups containing the correct reagent are selected and used for each measurement. 
     An automated analyzer for use with this type of measurement method comprises: a reading device; a sample dispenser; a seal breaker; a BF separator; a substrate dispenser; a detector; and a data analyzer (see Japanese Patent Laid-Open Publication No. 2001-165936). The reading device reads an identification marking made up of symbols, letters and the like, which is printed on the surface of the sealing member covering the reagent cup and indicates the item for analysis. The sample dispenser extracts a specimen of a sample such as blood from a specimen container such as a blood collection tube, and dispenses the specimen into a reagent cup. The seal breaker breaks the sealing member on the reagent cup to open the upper surface of the cup so that the sample can be dispensed into the reagent cup by the above sample dispenser. The BF separator separates and removes (by BF separation) enzyme labeled antibodies that exist in a liquid phase state in the sample-containing reaction fluid in the reagent cup into which the sample has been dispensed. The substrate dispenser adds a substrate for the labeled enzyme to the reagent cup following completion of the BF separation. The detector detects the level of fluorescence, light absorbance, light emission, or the like, which is used for measuring the labeled enzyme activity in the reagent cup after a predetermined length of time following dispensing of the substrate by the substrate dispenser. The data analyzer confirms the existence of, or determining the concentration of, a specific substance based on the signal intensity of the signal detected by the detector, which correlates with the existence of, or the concentration of, the specific substance. 
     In the case of heterogeneous sandwich EIA analysis using an enzyme for labeling, the reagent cup contains water insoluble magnetizable beads containing an immobilized antibody that undergoes a distinctive bonding with the specific substance, and an enzyme labeled antibody that undergoes a distinctive bonding with the specific substance, which are in a freeze-dried state. 
     In those cases where, as described above, magnetizable beads are placed in the reagent cups, by positioning a plurality of magnets, with the magnetic poles in an alternating arrangement, on a movable magnet plate that can move back and forth along the direction of movement of the reagent cups, and then moving this movable plate back and forth, the magnetizable beads in the reagent cups can be moved, enabling a stirring action to be initiated inside the reagent cups (see Japanese Patent Publication No. Hei 6-28594). 
     A conventional automated analyzer described above is also equipped with a transport device, which comprises a specimen container transport system that uses a chain conveyor or the like to move a plurality of the specimen containers in an endless manner, and a reagent cup transport system that uses a chain conveyor or the like to move a plurality of the reagent cups in an endless manner. The analyzer is configured so that when the specimen container transported by the specimen container transport system reaches a defined dispensing position, a predetermined quantity of the specimen is dispensed into a corresponding reagent cup that has been transported into position by the reagent cup transport system. 
     Because of the requirement to provide two separate transport systems, namely the specimen container transport system and the reagent cup transport system, the analyzer tends to be quite large. 
     Furthermore, by extending the length of the chain conveyors in the reagent cup transport system, the number of different reagent cups that can be provided for analyzing a single specimen can be increased, but such lengthening of the conveyor causes a corresponding increase in the heat capacity of the reagent cup transport system, which in turn increases the time required to adjust the temperature of the system to the predetermined operating temperature, thereby increasing the time between switching the analyzer on and beginning actual analysis. 
     Consequently, especially in those cases where rapid analysis is required, it is desirable that the analyzer is available for use as soon as possible after switching the apparatus on. 
     SUMMARY OF THE INVENTION 
     The present invention was deviced in view of the above factors, and it is an object of the present invention to provide an automated analyzer which can be installed in a restricted space, can be used in a short time of switching on, and provides superior operability. 
     A first aspect of the present invention provides an automated analyzer for analyzing a specific component in a specimen by sucking the specimen from a specimen container containing the specimen, and dispensing the specimen into a reaction container containing a reagent to initiate a reaction between the specimen and the reagent, comprising: a rotor which can rotate about a vertical central axis, and is provided with a plurality of specimen container holders which are evenly spaced around a large diameter circle centered on the central axis, for holding respectively, in a removable manner, the specimen container containing the specimen, and a plurality of reaction container holders that correspond with each of the specimen container holders, for holding respectively, in a removable manner, the reaction container sealed for containing the reagent for reacting with the specimen; a rotor driver for rotationally driving the rotor; a specimen dispenser for sucking the specimen in the specimen container held by any one of the specimen container holders and dispensing the specimen into the reaction container held by a predetermined reaction container holder predetermined from the reaction container holders; a temperature controlling element which is disposed along a movement route of the reaction container held by any one of the reaction container holders and maintain the temperatures of the reaction container at a constant temperature; and a stirrer which is disposed along the movement route of the reaction container held by any one of the reaction container holders and uses magnetic force to stir a mixed solution of the reagent and the specimen in the reaction container. 
     In a second aspect of the present invention, the automated analyzer also comprises a washing apparatus disposed around the periphery of the rotor, for washing the inside of the reaction container with a washing solution discharged from a nozzle device and sucking and removing the washing solution from the inside of the reaction container by use of the nozzle device at a position along a rotational direction of the rotor used during measurement where the reaction between the specimen and the reagent has finished. 
     In a third aspect of the present invention, the automated analyzer also comprises a substrate dispenser disposed around the periphery of the rotor at a more downstream position in the rotational direction of the rotor than the washing apparatus, for dispensing a substrate into the reaction container washed by the washing apparatus. 
     In a fourth aspect of the present invention, the rotor comprises a rotor main body formed as a cylindrical member, and the reaction container holders are provided at a predetermined spacing around the periphery of an upper flange formed on the inner peripheral of the top edge of the rotor main body, and the specimen container holders are provided around the outer periphery of the rotor main body, directly opposing the reaction container holders. 
     In a fifth aspect of the present invention, when the specimen container is taller, the top edge of the specimen container held in any one of the specimen container holders and the top edge of the reaction container held in any one of the reaction container holders are at substantially the same height. 
     In a sixth aspect of the present invention, the rotor driver is driven intermittently, with a single step equivalent to a rotational angle corresponding with a pitch with which the specimen container holders are provided on the rotor. 
     In a seventh aspect of the present invention, the specimen dispenser comprises a revolving device for revolving a specimen dispensing nozzle about the central axis of the rotor, a radial movement device for moving the specimen dispensing nozzle along a radial direction of the rotor, and a lift device for raising and lowering the specimen dispensing nozzle. 
     In an eight aspect of the present invention, the temperature controlling element is formed in a shape of a circular plate, and contacts lower surfaces of the reaction container holders provided on the rotor. 
     In a ninth aspect of the present invention, the reaction container holders hold respectively the reaction container so that the bottom of the reaction container is able to be inserted through and project slightly from the bottom of corresponding one of the reaction container holders. 
     In a tenth aspect of the present invention, the automated analyzer also comprises a rotor home position detector for detecting a predetermined stop position of the rotor as a home position of the rotor. 
     In an eleventh aspect of the present invention, the automated analyzer also comprises a rotor home position detector for detecting a predetermined stop position of the rotor as a home position of the rotor, wherein the rotor comprises a washing port into which the nozzle device of the washing apparatus is inserted, which is provided between the nozzle device of the washing apparatus and a substrate nozzle of the substrate dispenser when the rotor is positioned at the stop position as the home position of the rotor. 
     In a twelfth aspect of the present invention, at the home position of the rotor, the rotor is driven by the rotor driver so that the washing port moves to, and stops beneath the nozzle device of the washing apparatus and beneath the substrate nozzle, and the washing port is used for washing the nozzle device of the washing apparatus, and for discharging the substrate from the substrate nozzle to eject any air bubbles trapped in the substrate. 
     In a thirteenth aspect of the present invention, the automated analyzer also comprises a specimen container height detector for detecting the height of the specimen container held in any one of the specimen container holders provided on the rotor. 
     In a fourteenth aspect of the present invention, the automated analyzer also comprises a specimen container height detector for detecting the height of the specimen container held in any one of the specimen container holders provided on the rotor, wherein a distance below a liquid surface inside the specimen container to which the specimen dispensing nozzle is lowered is determined in accordance with the height of the specimen container detected by the specimen container height detector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view showing an immunoassay apparatus according to an embodiment of the present invention; 
         FIG. 2  is a top view of the immunoassay apparatus of  FIG. 1  with the carousel removed; 
         FIG. 3  is a top view of the immunoassay apparatus of  FIG. 2  with the heater removed; 
         FIG. 4  is a central longitudinal sectional view along the position A of  FIG. 1 ; 
         FIG. 5  is a top view of the carousel of  FIG. 1 ; 
         FIG. 6  shows a central longitudinal sectional view of the carousel of  FIG. 5 , as well as views of a specimen container holder, a reagent cup, and a cup holder; 
         FIG. 7  is a block diagram showing a control device of the immunoassay apparatus of  FIG. 1 ; 
         FIG. 8  is a flowchart showing an initialization process for the control device of  FIG. 7 ; and 
         FIG. 9  is a flowchart showing a measurement process for the control device of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will be described in detail in accordance with embodiments shown in the accompanying drawings. 
       FIG. 1  through  FIG. 6  show an embodiment of the automated analyzer of the present invention applied to an immunoassay apparatus that uses EIA procedures to analyze antibodies or antigens in a sample. 
       FIG. 1  is a top view showing a schematic illustration of the immunoassay apparatus,  FIG. 2  is a view of the apparatus of  FIG. 1  with the carousel that represents the rotor removed,  FIG. 3  is a view of the apparatus of the  FIG. 2  with the circular plate shaped heater that represents the temperature controlling element removed,  FIG. 4  is a longitudinal sectional view of  FIG. 1 ,  FIG. 5  is a plan view of the carousel of  FIG. 1 , and  FIG. 6  shows the carousel of  FIG. 5 , wherein (a) shows a longitudinal sectional view of the carousel, (b) shows a front view of a specimen container holder for holding a tube-like specimen container, (c) shows a side view of the specimen container holder, (d) shows a side view of a reagent cup that represents a reagent-carrying reaction container, (e) shows a top view of the reagent cup, and (f) shows a side sectional view of a cup holder that represents a reaction container holder. 
     In the drawings, the reference numeral  1  represents a base plate of the immunoassay apparatus, and a cylindrical carousel  2  that functions as a rotor is attached to substantially the center of the base plate  1  so as to freely rotate. As shown in  FIG. 2  and  FIG. 4 , a circular plate shaped heater  7  is attached to the apparatus base plate  1  substantially concentrically with the carousel  2  and in a position that corresponds with the position of reagent cups  6 . In addition, as shown in  FIG. 3  and  FIG. 4 , a circular plate shaped movable magnet plate  8  that functions as stirrer is attached to the apparatus base plate  1  below the heater  7 , in a concentric arrangement with the carousel  2 , and is able to move back and forth across the base plate  1 . 
     As shown in  FIG. 5  and  FIG. 6 , the carousel  2  comprises a cylindrical carousel main body  2   a  formed from a resin material such as polyacetal, together with a circular plate shaped upper flange  2   b  formed as a unit at the top inner peripheral section of the main body  2   a , and an inner peripheral edge  2   c  of this upper flange  2   b  is bent downward, forming a downward facing concave section  2   d  surrounded by this inner peripheral edge  2   c , the upper flange  2   b , and the inner peripheral surface of the carousel main body  2   a . Furthermore, an lower flange  2   e  is formed as a unit at the outer periphery  21  of the bottom of the carousel main body  2   a . A circular plate shaped drive ring  3  is secured to the bottom surface of this lower flange  2   e , and a drive gear that is not shown in the drawings meshes with a gear section  3   a  formed on the inner peripheral edge of the drive ring  3 , and is rotated by a carousel drive motor that is not shown in the drawings (but which corresponds with the step motor PM 6  shown in  FIG. 7 ). 
     A plurality of specimen container holders  4  are mounted at equal intervals in the circumferential direction around the outer periphery  21  of the carousel main body  2   a , and specimen containers can be either mounted in, or retrieved from, these holders along the vertical direction. Furthermore, a plurality of cup holder mounting apertures  2   f , equal to the number of specimen container holders  4 , are formed in the upper flange  2   b  of the carousel main body  2   a , directly opposing the specimen container holders  4 . 
     Cup holders  5  are inserted into these cup holder mounting apertures  2   f , with a slight gap left between each holder and aperture. 
     Each cup holder  5  is formed as a single integrated unit from a member with superior thermal conductivity such as aluminum, and as shown in  FIG. 6(   f ), comprises a holder main body section  5   a  formed in a cylindrical shape, and a flange section  5   b  that extends radially outwards from the bottom of the holder main body section  5   a . Each cup holder  5  is inserted into a cup holder mounting aperture  2   f  from underneath, and is prevented from falling by attaching a C-ring  5   d  to a peripheral slot  5   c  formed in the upper section of the cup holder  5  once the cup holder  5  has been passed through the aperture  2   f . Furthermore, the inner periphery of the holder main body section  5   a  is shaped so as to substantially conform with the exterior form of the reagent cup  6  shown in  FIGS. 6(   d ) and ( e ). When the reagent cup  6  is mounted inside the cup holder  5  under its own weight, the bottom end of the reagent cup  6  protrudes slightly below the bottom of the cup holder  5 . 
     When the carousel  2  is mounted in a rotatable manner to a predetermined position on the apparatus base plate  1 , the bottom ends of the cup holders  5  contact the upper surface of the circular plate shaped heater  7 , meaning that the bottom ends of the reagent cups  6  are lifted up slightly by contacting the upper surface of the heater  7 . In this state, because the reagent cups  6  are held in a slightly raised state with respect to the cup holders  5 , reagent cups  6  that have already been measured can be retrieved easily from their respective cup holders  5 . 
     The height of the carousel main body  2   a  of the carousel  2  is set so that when a tall blood collection tube  9   a  such as that shown in  FIG. 4  is mounted in a specimen container holder  4  as a specimen (sample) container, the top edge of this tall blood collection tube  9   a  and the top edge of the reagent cup  6  are at substantially the same height. 
     By so doing, in a configuration where the specimen containers are disposed at the outer periphery  21  of the carousel  2  and the reagent cups  6  are disposed at the inner periphery  2   k , the tall blood collection tube  9   a  does not impede access when mounting an unused reagent cup  6  in a cup holder  5 , or when retrieving a reagent cup  6  that has already undergone measurement from its cup holder  5 . Furthermore, as shown in  FIG. 4 , when a short sample cup  9   b  is mounted into a specimen container holder  4  as a specimen container, the top edge section of the sample cup  9   b  is designed so as to protrude from the top edge of the specimen container holder  4 . 
     Furthermore, the specimen container holders  4  are formed from the same material as the carousel main body  2   a , and each comprises a cutout section  4   a  in the front face that enables the reading of a barcode printed on a sheet and attached to the surface of a specimen container mounted inside the holder, with the barcode functioning as a unique identification marker for that particular specimen, and specimen container supports  4   b  which are provided at four positions around the inner periphery and protrude in towards the center of the specimen container holder  4  to support the mounted specimen container. Furthermore, a rear surface protrusion  4   c  formed on the rear surface of the specimen container holder  4  engages with a slit  2   i  formed in the carousel main body  2   a , and a bottom protrusion  4   d  engages with a mounting aperture  2   j  formed in the lower flange  2   e , thereby enabling the specimen container holder  4  to be mounted to the carousel main body  2   a  without the use of screws or the like. 
     Rollers  10  are mounted to the apparatus base plate  1  at four positions which coincide with the outer periphery  21  of the carousel main body  2   a , and the carousel  2  is supported by bringing the lower surface of the drive ring  3  into contact with these four rollers  10 . Furthermore, pressure rollers which are not shown in the drawings are also provided at three equally spaced positions around the outer periphery of the drive ring  3 , and by contacting the outer peripheral surface of the drive ring  3 , these three pressure rollers support the carousel  2  so that the carousel  2  enables rotation about the central rotational axis. 
     Furthermore, a protrusion  2   g  that enables detection of the home position (hereafter abbreviated as HP) of the carousel  2  is provided on the upper surface of the carousel  2 , and a washing tank  2   h  for the BF probe is provided between two cup holders  5 . 
     In the drawings, the reference numeral  11  represents an encoder plate, which comprises a cutout section  11   a  and coupled directly to the motor shaft of a carousel drive motor (not shown in the drawings) that is a pulse motor. One revolution of this encoder plate  11  causes the carousel  2  to move one pitch position. A detector  12  (represented by a sensor S 1  in  FIG. 7 ) for detecting the home position of the carousel  2  is provided above the rotational route followed by the carousel  2 , and when this carousel home position detector  12  detects the protrusion  2   g  on the carousel  2 , the current position is deemed the HP for the carousel  2 . At this point, if the cutout section  11   a  of the encoder plate  11  is simultaneously detected by another detector  13  (represented by a sensor S 4  in  FIG. 7 ) comprising a photosensor, then the control device determines that the pulse motor (the carousel drive motor) and the carousel  2  are connected correctly, whereas if a delay develops between the timing of detection by the detector  12  and that by the detector  13 , then the rotational position of the encoder plate  11  is adjusted until the detection timings of the detector  12  and the detector  13  coincide with each other. 
     In  FIG. 1  through  FIG. 3 , the region  27  indicated by an arrow at the bottom left of the figures is the region for mounting or retrieving specimen containers and reagent cups  6 , and is fitted with an openable door that is not shown in the drawings. Furthermore, other than this door, the remaining side surfaces are enclosed by side wall members  29   a  as shown in  FIG. 4 , and the upper surface of the apparatus is also covered with a top plate  29   b , meaning the interior of the immunoassay apparatus is isolated from the outside. 
     With the above mounting and retrieval region  27  functioning as the base point, the carousel  2  rotates intermittently in a clockwise direction. As the carousel  2  rotates, the height of each specimen container mounted in a specimen container holder  4  is detected from the side of the mounting and retrieval region  27  by a height detector  14  (represented by sensors S 2  and S 3  in  FIG. 7 ) and a determination is made as to whether the specimen container is a tall blood collection tube  9   a  or a short sample cup  9   b . The reason for checking the heights of the specimen containers at this point is to enable determination of the lowering distance for the dispensing nozzle which is described below. In the case where no specimen container is mounted in a specimen container holder  4 , a judgment of “no specimen container” is made. 
     This height detector  14  comprises a pair of upper and lower sensor members that are able to slide up and over the specimen containers mounted in the specimen container holders  4  as the carousel  2  rotates, and a pair of upper and lower switch members which are switched on by each of the sensor members as they contact a detector tube while moving up into a withdrawn position. 
     When a tall blood collection tube  9   a  reaches this height detection position, both the upper and lower sensor members are activated and both the upper and lower switch members output an ON signal. In contrast, when a short sample cup  9   b  reaches the height detection position, only the lower sensor member is activated and only the lower switch member outputs an ON signal. 
     Reagent cups  6  are also mounted in their respective cup holders  5  at the mounting and retrieval region  27 . The specimen container holders  4  and the cup holders  5  correspond, so that for each specimen container mounted in a specimen container holder  4 , a corresponding reagent cup  6  is mounted in the cup holder  5  that corresponds with the specimen container holder  4  holding that specimen container. In those cases where a plurality of different items are to be measured for a sample from a single specimen container, the single specimen container is mounted in a single specimen container holder  4 , and the reagent cups  6  for each of the items to be measured are mounted sequentially in cup holders  5 , beginning with the cup holder  5  corresponding with the specimen container and then moving upstream relative to the direction of carousel rotation. In such cases, the present embodiment enables measurement of up to 5 items. 
     A barcode reader  15 , which functions as identification information reading means for reading the unique identification information displayed on the surface of each specimen container, is disposed adjacent to the height detector  14  in a downstream position relative to the direction of the carousel  2  rotation, and is positioned at a height that corresponds with the cutout sections  4   a  provided in the specimen container holders  4 . This barcode reader  15  reads the barcode as the unique identification information for each specimen container that is displayed on the surface of the specimen container through this cutout section  4   a . The unique identification information for the specimen container read by the barcode reader  15  is transmitted to the control device, which controls the overall operation of the immunoassay apparatus. 
     Furthermore, the specimen container barcode reading position A for the barcode reader  15  is a stop position for the carousel  2 , and at this position the specimen container holder  4  and the cup holder  5  are aligned in the radial direction. 
     In addition, in this embodiment, 25 specimen container holders  4  and 25 cup holders  5  are provided at equal intervals around the circumference of the carousel  2 , and consequently if the carousel  2  is rotated in 14.4 degree steps (hereafter referred to as a 1-step rotation), then each specimen container holder  4  and corresponding cup holder  5  can be moved progressively. 
     An imaging device  16  such as a CMOS camera for reading an identification marking  6   b , which is displayed on the surface of a sealing member  6   a  (see  FIG. 6(   e )) covering the top opening of the reagent cup  6  mounted in the cup holder  5  and indicates the item for analysis, is also disposed at the same position as the barcode reading position, but is positioned above the cup holder  5 . The analysis item for the reagent cup  6  read by the imaging device  16  is stored for each specimen. 
     A seal breaker  17  is disposed at a position B, which is for example a 1-step rotation of the carousel  2  from the position A, and this seal breaker  17  uses a needle-like breaker (not shown in the drawings) that moves up and down to pierce the sealing member  6   a  covering the reagent cup  6  from above. The breaker is then pushed down further to spread and open the broken sealing member  6   a , thereby exposing the top opening of the reagent cup  6 , and is then raised in preparation for the next 1-step rotation of the carousel  2 . 
     The region between a position C, which is a 1-step rotation from the position B, and a position D which is a further 4-step rotations from the position C is defined as the sample dispensing region E, and a sample dispenser  18  dispenses samples from the specimen containers held by the specimen container holders  4  within this sample dispensing region E into the corresponding reagent cups  6  that have been opened by the seal breaker  17 . 
     In this embodiment, the sample dispenser  18  comprises a revolving tower  18   a , a horizontally extended arm  18   b , a nozzle support  18   c , and a sample dispensing nozzle  18   d . The revolving tower  18   a  (see  FIG. 4 ) has its rotational center positioned at the rotational center position O of the carousel  2 , and extends in a vertical direction, and is rotationally driven within the sample dispensing region E by a revolving drive mechanism that uses a revolving motor (not shown in the drawings, but equivalent to the motor PM 3  in  FIG. 7 ) formed from a pulse motor as the drive source. The horizontally extended arm  18   b  is supported so that it enables the arm to be raised and lowered with respect to the revolving tower  18   a , and is raised and lowered by a lift drive mechanism that uses a lift motor  34  ( equivalent to the motor PM 1  in  FIG. 7 ) formed from a pulse motor as the drive source. The nozzle support  18   c  is supported so that it enables horizontal movement with respect to the arm  18   b  and is moved horizontally by a horizontal movement motor (not shown in the drawings, but equivalent to the motor PM 2  in  FIG. 7 ) formed from a pulse motor. The sample dispensing nozzle  18   d  is supported by the nozzle support  18   c  with the tip of the nozzle facing downwards. 
     The top end of the dispensing nozzle  18   d  is connected to a sample dispensing syringe  22  formed from a plunger-type precision pump by a flexible connection pipe that is not shown in the drawings, and this syringe sucks a predetermined quantity of the sample from inside a specimen container and dispenses the sample into a reagent cup  6 . 
     In the sample dispenser  18 , the position in which the arm  18   b  is stopped at the position C, and the nozzle support  18   c  is stopped in a position that locates the dispensing nozzle  18   d  directly above either the specimen container holder  4  or the cup holder  5  is deemed the home position for the dispensing nozzle  18   d , and in the following description, the position above the cup holder  5  at position C is deemed the home position (hereafter abbreviated as HP). 
     When the carousel  2  undergoes a 1-step rotation, and a specimen container mounted in a specimen container holder  4  reaches the position C, the sample dispenser  18  drives the horizontal movement motor to move the nozzle support  18   c  out towards the tip of the arm  18   b , and once the sample dispensing nozzle  18   d  is positioned directly above the specimen container the horizontal movement motor is stopped. 
     Subsequently, the lift motor  34  is activated, and the arm  18   b  is lowered until the dispensing nozzle  18   d  is inserted into the specimen container. 
     The dispensing nozzle  18   d  is formed from a conductive material such as stainless steel, and when the tip of the dispensing nozzle  18   d  reaches the liquid surface in the specimen container, the liquid surface is detected by a liquid surface detection circuit (not shown in the drawings). The lift motor  34  is then driven further to lower the dispensing nozzle  18   d  into the sample inside the specimen container. Because the height of the specimen container has been determined in advance by the height detector  14 , the lift motor  34  is instructed to use a deep insertion in the case of a tall blood collection tube  9   a , as the bottom of the specimen container sits at a low position enabling the dispensing nozzle  18   d  to be inserted deeply into the tube without causing any damage, whereas in the case of a short sample cup  9   b , the lift motor  34  is instructed to use a shallow insertion, as the bottom of the specimen container sits at a higher position. 
     A predetermined quantity of sample is sucked by the sample dispensing syringe  22 , the lift motor  34  is instructed to raise the arm  18   b , and the dispensing nozzle  18   d  is removed from the specimen container and then moved by the horizontal movement motor to the dispensing nozzle HP. At the dispensing nozzle HP, the height from the tip of the dispensing nozzle  18   d  down to the reagent cup  6  is constant, and consequently from this point the lift motor  34  is activated and the arm  18   b  is lowered by a predetermined quantity so as to insert the tip of the dispensing nozzle  18   d  to a predetermined depth inside the reagent cup  6 . The sample dispensing syringe  22  then discharges and the sucked sample is dispensed into the reagent cup  6 . The lift motor  34  is then activated again, the arm  18   b  is raised, and the dispensing nozzle  18   d  is returned to the HP. 
     One cycle of this dispensing process is completed very quickly, and there is still time available before the next 1-step rotation of the carousel  2 , and consequently during this available time the revolving motor is activated, rotating the revolving tower  18   a  in a clockwise direction, so that the arm  18   b  revolves through the horizontal plane in the clockwise direction. When the arm  18   b  reaches the position D, the horizontal movement motor is activated and the nozzle support  18   c  is moved horizontally towards the rotational center O. When the dispensing nozzle  18   d  reaches a position above an dispensing water tank  28  used for washing the dispensing nozzle  18   d , the horizontal movement motor is stopped, the lift motor  34  is activated, and the arm  18   b  is lowered by a predetermined level, immersing the dispensing nozzle  18   d  in the washing solution inside the dispensing water tank  28 . 
     Once the dispensing nozzle  18   d  is immersed in the washing solution inside the dispensing water tank  28 , the suction and discharge operations of the dispensing syringe  22  are repeated a number of times, thoroughly washing the dispensing nozzle  18   d , the dispensing syringe  22 , and the inside of the connection pipe linking the two. Then, when the next 1-step rotation of the carousel  2  is approaching, the dispensing nozzle  18   d  is returned to the dispensing nozzle HP using the opposite operations to those described above, in preparation for the next dispensing process. At this time, a warning lamp  26  provided on the apparatus base plate  1  within the mounting and retrieval region  27  is lit or begins to flash, informing the operator that the next rotation of the carousel  2  is approaching, and prompting the mounting or retrieval of specimen containers and/or reagent cups  6 . 
     Provided a specimen container is mounted in the specimen container holder  4  of the carousel  2 , a dispensing operation is conducted into the corresponding reagent cup  6  sitting directly inside that specimen container. However, in the case where up to 5 different measurements are conducted on a specimen from a single specimen container (hereafter this type of multiple measurement is referred to as a “multi-dispensing ”), although reagent cups  6  will be mounted in the second and subsequent cup holders  5 , no specimen containers are mounted in the corresponding specimen container holders  4  sitting directly outside the second and subsequent cup holders  5 . A multi-dispensing corresponds with a state where OFF signals from both the upper and lower switch members of the height detector  14 , and/or an “unreadable” signal from the barcode reader  15  are input into the control device, but reading of the identification information by the imaging device  16  occurs normally. Accordingly, the control device instructs the sample dispenser  18  to dispense the sample inside the specimen container into the second and subsequent reagent cups  6  at the dispensing nozzle HP. 
     When a multi-dispensing commences, the second reagent cup  6  is located at the position C and the specimen container is positioned a 1-step rotation from the position C. When the third reagent cup  6  reaches the position C the specimen container has undergone a further 1-step rotation, and in the case where a maximum fifth reagent cup  6  has reached the position C, the specimen container has reached the position D. 
     As a result, the sample dispenser  18  is driven by the revolving motor in 1-step rotations from the position C to as far as the position D, and one cycle of the dispensing process described above is performed at each of the positions within the dispensing region D. For example, in the case in which three measurements are performed using a single sample, first a sample is sucked up by the dispensing nozzle  18   d  from the specimen container at a position 1-step rotation away from the position C, and the arm  18   b  is then returned to the position C, the dispensing nozzle  18   d  is returned to its HP, and the sample is dispensed into the second reagent cup  6 . Then, when the third reagent cup  6  reaches the position C, a sample is sucked up by the dispensing nozzle  18   d  from the specimen container at a position 2-step rotations away from the position C, and the dispensing nozzle  18   d  is then returned to its HP as above, and the sample is dispensed into the third reagent cup  6 . 
     On the next 1-step rotation of the carousel  2 , the height detector  14  or the barcode reader  15  detect the fact that a specimen container is mounted in the specimen container holder  4  now located at the position C, and this detection can be used to determine the completion of the multi-dispensing. Of course, information detailing the multi-dispensing could also be manually input into the control device. 
     The circular plate shaped heater  7  is disposed beneath the carousel  2 , and adjusted the temperature to a predetermined temperature (for example, 37 degrees Celsius) by the control of the control device. This heater  7  must maintain the temperature inside the reagent cups  6  at a constant value, allowing the reaction inside the reagent cups  6  to proceed, from the position C where the sample is dispensed into the reagent cup  6 , through until a detection position H, where measurements are conducted following the dispensing of a substrate into the reagent cup  6  at a substrate dispensing position G. However in this embodiment, because of ease of manufacture, the heater  7  is formed with the heater element extending across the entire surface of the circular plate shaped hard base plate, and the heater  7  contacts the flange sections  5   b  at the bottom of all of the cup holders  5 , leaving a slight gap between the inner peripheral surface of each cup holder  5  and the corresponding reagent cup  6 . As a result, the cup holders  5  can be efficiently maintained at the predetermined temperature at all times, and even when an unused reagent cup  6  is mounted in a cup holder  5 , there is little decrease in temperature, and the time required to reach the predetermined temperature following dispensing can also be reduced. 
     Furthermore, the bottom of the reagent cup  6  penetrates into the opening at the bottom of each cup holder  5 , meaning each reagent cup  6  also contacts the heater  7  directly, which enables the temperature inside the reagent cups  6  to be maintained efficiently at the predetermined value. 
     In addition, because the concave section  2   d  is formed in a circumferential direction beneath the upper flange  2   b  of the carousel  2 , and the heater  7  is positioned opposing this concave section  2   d , warm air is trapped within the concave section  2   d , further improving the heat retention properties, and enabling the temperature inside the reagent cups  6  to be maintained even more efficiently. 
     Furthermore, because the carousel  2  is configured with the reagent cups  6  positioned on the inside of the carousel main body  2   a  and the sample-carrying specimen containers positioned on the outside, and with the heater  7  disposed only on the inside of the carousel main body  2   a , heat from the heater  7  is not transferred to the samples contained in the specimen containers, thereby isolating the samples in the specimen containers from any adverse heating effects. 
     On the other hand, the circular plate shaped movable magnet plate  8  is disposed beneath the heater  7  with a suitable spacing therebetween, and as shown in  FIG. 3 , a plurality of magnets  8   b ,  8   c  are disposed around the circumference of the movable magnet plate main body  8   a , with the magnetic poles in an alternating arrangement (shown as black and white circles), from the position C where the samples are dispensed into the reagent cups  6  through until the detection position H. When the movable magnet plate main body  8   a  is moved back and forth, the magnetizable beads inside the reagent cups  6  also move, causing a stirring action inside the reagent cups  6 . 
     As shown in  FIG. 4 , the movable magnet plate main body  8   a  of this movable magnet plate  8  is supported in a rotatable manner by engaging with the circumferential slots of a plurality of guide pulleys  30  formed along both the inner peripheral and outer peripheral edges of the movable magnet plate main body  8   a , which is secured to the apparatus base plate  1 . These guide pulleys  30  are provided on a plurality of support bars  31  which are secured to the apparatus base plate  1  and extend vertically upwards. Furthermore, a slot  8   d  that extends in a radial direction is formed in the inner peripheral surface of the movable magnet plate main body  8   a , and a cam follower  32   a  provided on an eccentric cam plate  32 , which is rotated using a reciprocating drive motor (not shown in the drawings, but equivalent to the motor PM 4  in  FIG. 7 ) formed from a pulse motor as the drive source, engages with this slot  8   d , causing the movable magnet plate main body  8   a  to rotate back and forth as the eccentric cam plate  32  undergoes rotation in a single direction. 
     The circular plate shaped heater  7  is secured to the top of the support bars  31 . 
     A washing device  19  is disposed at a position F, which is designated as the washing position, and by the time a reagent cup  6  reaches this position F, where the reaction that started at the position C has already progressed satisfactorily. 
     The washing device  19  is disposed at a stop position of the carousel  2 , and comprises a BF probe (not shown in the drawings), for example, with a double nozzle structure (nozzle device  19   b ) positioned above the reagent cup  6  with the bottom up, and a BF probe lifting gear  19   a  that enables the BF probe to be raised and lowered. 
     When a 1-step rotation of the carousel  2  brings a reagent cup  6  mounted in a cup holder  5  of the carousel  2  to the position F, the BF probe is inserted inside the reagent cup  6 , and the discharge action of a BF syringe  23  is used to inject washing water, which has been heated to a predetermined temperature by a washing water heater  24 , through the BF probe into the reagent cup  6 . Subsequently, the suction action of a waste water pump (not shown in the drawings) is used to suck, and discharge the liquid from inside the reagent cup  6 . These discharge and suction operations are repeated, and on completion of this so-called BF separation which washes the inside of the reagent cup  6 , the BF probe lifting gear  19   a  is raised using a BF probe motor (not shown in the drawings, but equivalent to the motor PM 7  in  FIG. 7 ) formed from a pulse motor as the drive source, via a BF probe lift drive mechanism, thereby removing the BF probe from the reagent cup  6  and completing the BF separation process. 
     Following completion of the BF separation process, the carousel  2  undergoes a further 1-step rotation, and the reagent cup  6  that has been subjected to the BF separation process reaches the position G. 
     A substrate dispenser  20  is disposed at the position G, and a downward facing substrate nozzle that points towards the reagent cup  6  is fitted to this substrate dispenser  20 . The action of a substrate syringe  25  is used to dispense substrate from the substrate nozzle positioned above the reagent cup  6 , and this addition of the substrate causes the generation of a measurable signal (which is detected as, for example, a variation in light absorbance, a variation in fluorescent intensity, or the emission of light) due to the enzyme activity. 
     The next 1-step rotation of the carousel  2  moves the reagent cup  6 , containing the added substrate at the position G, to the position H. 
     A data analyzer  21  is disposed at the position H. In this embodiment, the data analyzer  21  uses a fluorescence detector, which measures the fluorescent intensity or the like inside the reagent cup  6 , and then sends the result of the measurement to the control device. The control device outputs the measurement results to a printer  49 , which prints them onto recording paper. 
     When the carousel  2  is positioned in its home position, the BF probe washing tank  2   h  provided on the upper surface of the carousel  2  is positioned between the BF probe at the position F and the substrate nozzle of the substrate dispenser  20 . In other words, the ½-step (7.2 degrees) rotation of the carousel  2  in a counterclockwise direction from its HP moves and positions the BF probe washing tank  2   h  directly below the BF probe. In this position, the BF probe is lowered and immersed in the washing solution inside the BF probe washing tank  2   h , and the discharge action of the BF syringe  23  and the suction action of the waste water pump are repeated, which sucks the washing solution from the BF probe washing tank  2   h  up through a BF probe suction pipe, and discharges this sucked washing solution out through a BF probe discharge pipe, thereby washing the BF probe. 
     Furthermore, the ½-step rotation of the carousel  2  in a clockwise direction from its HP moves and positions the BF probe washing tank  2   h  directly below the substrate nozzle. In this position, the suction and discharge actions of the substrate syringe  25  are repeated, thereby ejecting from the substrate nozzle any air bubbles trapped in the substrate. 
     The operations for rotating the carousel  2  ½-step in both the counterclockwise direction and the clockwise direction in order to wash the BF probe and eject air bubbles from the substrate nozzle respectively, can be performed either during startup of the immunoassay apparatus, or at a predetermined time interval. 
     The control device for the immunoassay apparatus of the present embodiment is shown in  FIG. 7 . 
     In the control device of this embodiment, a main control circuit  40  outputs a variety of different drive signals to a drive circuit  41 , which in turn controls the driving of a series of pulse motors PM 1  to PM 10  and a heater  50 . Furthermore, control of the driving of each of the motors PM 1  to PM 10 , and temperature control of the heater  50  is performed on the basis of sensor signals input into a sensor circuit  42  from sensors S 1  to S 5 . 
     The motor PM 1  is the lift motor  34  for raising and lowering the arm  18   b  in the sample dispenser  18 , the motor PM 2  is the horizontal movement motor for moving the nozzle support  18   c  of the sample dispenser  18  in a horizontal direction, and the motor PM 3  is the revolving motor for rotating the revolving tower  18   a  of the sample dispenser  18 . 
     The motor PM 4  is the reciprocating drive motor for driving the movable magnet plate  8  back and forth, the motor PM 5  is the seal breaker motor for moving the breaker of the seal breaker  17  up and down, the motor PM 6  is the carousel drive motor for performing rotational driving of the carousel  2 , and the motor PM 7  is the BF probe motor for raising and lowering the BF probe. 
     The motor PM 8  is the substrate syringe motor of the substrate dispenser  20 , the motor PM 9  is the washing syringe motor of the washing device  19 , and the motor PM 10  is the injection syringe motor of the sample dispenser  18 . The reference numeral  50  represents the heater for maintaining the reagent cups  6  at a constant temperature. 
     The sensor S 1  is the sensor for detecting the home position of the carousel  2 , the sensor S 2  is the sensor for detecting tall specimen containers, the sensor S 3  is the sensor for detecting short specimen containers, the sensor S 4  is the sensor for detecting one pitch of the drive motor PM 6  of the carousel  2 , the sensor S 5  is the sensor for detecting the liquid surface level using the sample dispensing nozzle  18   d , and the sensor S 6  is the sensor for detecting the temperature of the heater  50 . 
     The reference numeral  43  represents the power supply circuit for supplying power to the main control circuit  40 , the drive circuit  41 , and the sensor circuit  42 , and the reference numeral  44  represents the power supply switch for the immunoassay apparatus. 
     The reference numeral  45  represents the warning lamp for warning of events such as the impending start of rotation of the carousel  2 , the reference numeral  46  represents the camera for reading the identification information displayed on the sealing member of each reagent cup  6 , the reference numeral  47  represents the barcode reader for reading the barcode displayed on each specimen container, the reference numeral  48  represents a display unit comprising a liquid crystal display device (LCD), a touch panel, and a keyboard or the like combined in a single unit and provided on the outside surface of the immunoassay apparatus, and the reference numeral  49  represents a printer for printing measurement results onto recording paper. 
     As follows is a description of the operation of the control device shown in  FIG. 7 , based on the flowcharts shown in  FIG. 8  and  FIG. 9 . 
       FIG. 8  is a flowchart showing the initialization process conducted when the power supply switch is turned on. 
     In  FIG. 8 , when the power supply switch  44  is turned on (Step  1 ), the motor PM 6  is activated and undergoes step rotation in the forward direction, causing the carousel  2  to rotate intermittently in the clockwise direction (Step  2 ). Power supply to the heater  50  is also started. At this point, the motor PM 4  may be activated to start the back and forth movement of the movable magnet plate  8 . Alternatively, the motor PM 4  may be activated after completion of the initialization process. 
     When the sensor S 1  detects that the carousel  2  has reached its HP (Step  3 ), a judgment is made as to whether or not the sensor S 4  for detecting the rotational position of the encoder plate  11  of the carousel drive motor PM 6  is ON (Step  4 ), and if the carousel  2  is stopped and the sensor S 4  is OFF, then a fault is determined to have occurred in the driving of the carousel  2 , and this fault is displayed on the liquid crystal display device (Step  5 ). The carousel drive motor is then stopped. 
     If the carousel  2  is stopped and the sensor S 4  is ON, then the carousel  2  is judged to be functioning normally. 
     Next, when the detected temperature from the sensor S 6  reaches the predetermined control temperature of the heater  50  (Step  6 ), this initialization process ends, and the apparatus moves to a standby mode, waiting for measurements. 
     Alternatively, when the carousel  2  is positioned at the HP and the sensor S 4  at Step  4  is ON, the carousel  2  may first be rotated ½-step in the counterclockwise direction, and the motor PM 7  is activated to insert the BF probe in the BF probe washing tank  2   h . Then, the motor PM 9  is activated to wash the BF probe through a series of suction and discharge operations through the BF probe, the BF probe is returned to its raised position, and a 1-step rotation of the carousel  2  in the clockwise direction is then conducted. Then, the motor PM 9  is activated and a series of suction and discharge operations of the substrate syringe are used to discharge substrate from the substrate nozzle into the BF probe washing tank  2   h  while ejecting any air bubbles trapped in the substrate. 
     Next is a description of the measurement process, based on the flowchart of  FIG. 9 . 
     The measurement process comprises a specimen container height detection mode, a barcode reading mode for reading the barcode on a specimen container, a reagent cup reading mode using a camera  46 , a seal break mode using the seal breaker  17 , a sample dispensing mode, a BF separation mode, a substrate dispensing mode, and a data analysis mode, and the respective modes are executed independently in parallel. The BF separation mode, the substrate dispensing mode, and the data analysis mode have already been described, and are relatively simple processes, and as such they are omitted from  FIG. 9 . Furthermore, during the measurement process, the operation described above for washing the BF probe and ejecting air bubbles trapped in the substrate may be conducted every time the carousel  2  reaches the HP, or after several revolutions of the carousel  2 . 
     Once the apparatus has reached a state in which the measurement process can be conducted, the carousel  2  undergoes a 1-step rotation, and a check is made as to whether or not the height detection sensor S 3  is ON (Step  11 ). If the sensor S 3  is ON, then the sensor S 2  is checked (Step  12 ), and if the sensor S 2  is OFF, then the specimen container is judged to be a short sample cup  9   b  and a specimen container Low level signal is output (Step  13 ). If the sensor S 2  is ON, then the specimen container is judged to be a tall blood collection tube  9   a  and a specimen container High level signal is output (Step  14 ). 
     If the sensor S 3  is OFF at Step  11 , then a determination is made as to whether or not the current sample dispensing process is a multi-dispensing (Step  15 ). 
     If the result at Step  15  rules out a multi-dispensing, then a check is made as to whether or not the sensor S 2  is ON (Step  16 ), and if the sensor S 2  is OFF, a determination is made as to whether or not a reagent cup  6  is mounted in the corresponding cup holder  5  using imaging information from the camera  46  (Step  17 ). 
     In the reagent cup reading mode conducted at Step  24 , based on the imaging information from the reagent cup  6  captured by the camera  46 , (1) if the identification marking is read correctly, a “reagent cup mounted” signal is output, (2) if the presence of a reagent cup  6  can be confirmed but the identification marking on the sealing member  6   a  is unable to be read, then the sealing member  6   a  has already been broken and opened, and so an assumption is made that the retrieval of an already measured reagent cup has been overlooked, and a “retrieval forgotten” signal is output, and (3) if the presence of a mounted reagent cup  6  cannot be confirmed, then a “no reagent cup mounted” signal is output. These signals, together with any acquired identification marking information, are stored in memory (Step  28 ). 
     If neither of the height detection sensors S 2 , S 3  detect the presence of a specimen container, and no reagent cup is mounted, then the process returns to Step  11 , and this subroutine is repeated until the sensor S 3  turns ON. Furthermore, if the sensor S 2  is ON at Step  16 , then a malfunction is judged to have occurred, and an abnormal operation warning is output (Step  18 ). 
     At Step  17 , if either of the aforementioned “reagent cup mounted” or “retrieval forgotten” signal has been output, then a reagent cup  6  is judged to be present, and the process proceeds to Step  19 . 
     At Step  19 , if the “reagent cup mounted” signal has been output, then the process proceeds to Step  21 , a multi-dispensing is confirmed, and the sample dispenser  18  conducts injection operations in accordance with a multi-dispensing process. If the “retrieval forgotten” has been output then the process proceeds to Step  20  and injection is prohibited. 
     Furthermore at Step  15 , if the current sample dispensing process is a multi-dispensing, then the multi-dispensing process is continued at Step  22 . 
     The sample dispensing process is conducted under multi-dispensing, and if the maximum of 5 dispensing processes have then been conducted, or if the sensor S 3  detects a specimen container at Step  11 , then the multi-dispensing ends (Step  23 ). This completes the specimen container height detection mode. 
     In the barcode reading mode conducted at Step  25 , if the signal is a signal representing the barcode reading result (or a readable signal) (Step  26 ), it is stored in memory (Step  28 ). 
     In the seal break mode using the seal breaker  17 , a judgment is made at Step  29  as to whether or not the reagent cup  6  that has arrived at the position B where seal breaking is conducted has been designated “dispensing prohibited”. If the cup has been designated “dispensing prohibited” then seal breaking is not performed (Step  30 ), but otherwise the seal breaking operation is executed (Step  31 ). 
     In the sample dispensing mode, a judgment is made at Step  32  as to whether or not a multi-dispensing is in progress, and in the case of a multi-dispensing, the lift motor PM 1 , the horizontal movement motor PM 2 , the revolving motor PM 3 , and the dispensing syringe motor PM 10  of the sample dispenser  18  are all activated appropriately. Then, the appropriate number of 1-step rotations from the position C are performed by sequentially increasing the angle of revolution of the revolving motor PM 3  to suck a sample from the specimen container, and this sample is then dispensed into the reagent cup  6  at the position C (Step  33 ). If the dispensing process is not a multi-dispensing, then the lift motor PM 1 , the horizontal movement motor PM 2 , and the dispensing syringe motor PM 10  are all activated appropriately at Step  34 , and the sample dispensing nozzle is moved horizontally and up and down solely at the position C, and a sample from the specimen container is dispensed into the reagent cup  6 . Subsequently, before the next dispensing process is started, and regardless of whether or not a multi-dispensing is in progress, the motor PM 3  is used to rotate the sample dispensing nozzle  18   d  to the position D, the motor PM 2  is then activated and used to position the sample dispensing nozzle  18   d  over the dispensing water tank  28 , and the motor PM 1  is then activated and used to immerse the sample dispensing nozzle  18   d  in the washing solution inside the dispensing water tank  28 , thereby washing the sample dispensing nozzle  18   d.    
     This completes the description of the operation of this embodiment. In this embodiment, pulse motors were used as the drive sources for driving the various members of the immunoassay apparatus, but the present invention is not restricted to this configuration, and any of a variety of other motors can also be used. 
     Furthermore, the temperature controlling element is not restricted to element for raising the temperature, and where required may also include element for cooling or lowering the temperature, such as heat radiating element formed from a heat conductive metal plate with a series of surface irregularities on the rear surface. 
     Furthermore in the present embodiment, the stirrer based on the movable magnet plate  8  was used for stirring the reagent and specimen mixtures, but if stirring is unnecessary then the stirrer and associated means may be omitted. 
     As described above, according to the present invention, a single rotor is used to move specimen containers and reagent-carrying reaction containers in a single direction while dispensing specimen samples into the reaction containers, and the measurements are completed within a single complete rotation, and as a result the overall size of the apparatus can be reduced. Furthermore, because mounting and retrieval of the specimen containers and reagent-carrying reaction containers is conducted at a single location, the operability of the apparatus is good. 
     According to a fourth aspect of the present invention, because the specimen containers can be mounted at the outer periphery of the rotor, the operations for mounting and retrieving the specimen containers are simple, and furthermore because the reaction containers can be mounted at the upper surface of the rotor, the operations for mounting and retrieving the reaction containers are also simple. Furthermore, because the reagent-carrying reaction containers can be mounted directly opposing the corresponding specimen containers, there is little danger of mounting containers in the wrong position. 
     According to the fifth aspect of the present invention, reagent-carrying reaction containers can be mounted and retrieved without tall specimen containers causing an impediment to access. 
     According to the sixth aspect of the present invention, positional control of the rotor is conducted using a rotational angle that corresponds with the positional pitch of the specimen container holders, and consequently the rotor can be moved accurately to the variety of devices disposed around the periphery of the rotor. 
     According to the seventh aspect of the present invention, the specimen dispenser can be positioned inside the rotor, which contributes to further miniaturization of the apparatus. 
     According to the eighth aspect of the present invention, because the temperature controlling element is formed in the shape of a circular plate, it occupies little space, and also contacts the lower surfaces of the reaction container holders of the rotor, enabling the reaction containers to be effectively heated via the reaction container holders. 
     According to the ninth aspect of the present invention, the reaction containers also contact the surface of the heater directly, enabling even more efficient heating of the reaction containers. 
     According to the tenth aspect of the present invention, by checking whether or not the rotor driver is stopped at its home position when the rotor has reached its home position, a judgment can be made as to whether or not synchronization of the rotor driver with the rotor has been achieved. 
     According to the eleventh and twelfth aspects of the present invention, when the rotor reaches the rotor home position, a slight back and forth movement of the rotor enables the nozzle device of the washing apparatus to be washed using the washing port provided on the rotor, and also enables any air bubbles trapped in the substrate to be ejected by discharging substrate from the substrate nozzle. 
     According to the thirteenth and fourteenth aspects of the present invention, the distance below the liquid surface inside the specimen container to which the specimen dispensing nozzle is lowered is determined in accordance with the height of the specimen container held in the specimen container holder of the rotor, and consequently inadvertent overly-deep insertion of the specimen dispensing nozzle into the specimen container can be prevented.