Abstract:
An automatic analyzer having a positioning member connected to a nozzle support jig used to install a rinse nozzle having a suction member. The positioning member is present at a lower position than that of the suction member, has a vertically movable construction, and during a downward movement of the rinse mechanism, is brought close to/inserted into the reaction cuvette earlier than the suction member. Thus, the positioning member adjusts an inserting position of the suction member appropriately if the stopping position of the reaction cuvette deviates.

Description:
INCORPORATED BY REFERENCE 
     The present application claims priority from Japanese application 2007-221989 filed on Aug. 29, 2007, the contents of which are hereby incorporated by reference into this application. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to automatic analyzers for analyzing biological samples such as blood and urine, and more particularly, to an automatic analyzer with a rinse mechanism for rinsing a reaction cuvette. 
     2. Description of the Related Art 
     Automatic analyzers that conduct qualitative and/or quantitative analyses on a biological sample such as blood or urine cause the sample and a reagent to react in a reaction cuvette and analyze the constituents of the sample that are to be measured. After one measuring operation, the reaction cuvette formed of a material such as a plastic or glass is generally rinsed for reuse. The reaction cuvette, after being moved to a required rinsing position, is usually rinsed by suctioning the reaction liquid (the liquid left as a waste liquid after the measurement) with a nozzle, then repeating injection and suction of water, rinse water, or the like a required number of times, and finally suctioning the rinse water. In order to prevent the rinse water from remaining in the reaction cuvette after the rinsing thereof, a suction member formed to extend along the inner wall of the reaction cuvette is installed at the tip of a rinsing nozzle. JP-A-10-062431 describes a technique for forming a suction member to minimize the amount of rinse water left unsuctioned. 
     SUMMARY OF THE INVENTION 
     As described in JP-A-10-062431, the clearance between the rinse nozzle tip and the inner wall of the reaction cuvette is commonly made as small as possible for a minimum amount of rinse water left unsuctioned. Meanwhile, the positioning accuracy of the reaction cuvette in the rinsing position is required to be higher as the clearance is reduced. Automatic analyzers are required to be miniaturized, to be enhanced in throughput and in operating speed, and to employ a more compact reaction cuvette for the use of samples and reagents in microquantities. These requirements are placed under the relationship of trade-offs with respect to the improvement of reaction cuvette stopping position accuracy, and merely reducing the clearance increases a chance of nozzle tip trouble due to a collision with the reaction cuvette. 
     An object of the present invention is to provide a highly reliable automatic analyzer comprising a rinse mechanism adapted such that a suction member is reliably inserted into a reaction cuvette without deterioration of rinse liquid suction performance, without dimensional increases of the reaction cuvette or of the apparatus, and without being affected by stopping position accuracy of the reaction cuvette. 
     In order to achieve the above object, the present invention has the following configuration: 
     An automatic analyzer comprises a reaction cuvette for mixing a sample and a reagent, a reaction disk for setting up the reaction cuvette thereon and transferring the reaction cuvette to a rinsing position, a rinse nozzle that suctions rinse water in the reaction cuvette, a suction member connected to the rinse nozzle, and a shifter for moving the rinse nozzle; wherein the analyzer is further provided with a controller which, in accordance with the position of a positioning guide provided on the reaction cuvette, controls the shifter such that the rinse nozzle is inserted into the cuvette. 
     A more specific example is shown below. In an automatic analyzer comprising at least a reaction cuvette for mixing a sample and a reagent; a reaction disk for setting up the reaction cuvette thereon and transferring the cuvette to a rinsing position; and a rinse mechanism comprising a rinse nozzle that suctions and discharges rinse water injected into the reaction cuvette, a suction member connected to a tip of the rinse nozzle, a nozzle support jig for supporting the rinse nozzle, a vertically moving arm fastened to the nozzle support jig, a shifter including a feed screw to move the arm vertically, and a motor, the nozzle support jig for installing the rinse liquid suction nozzle to which the suction member is connected includes a positioning member, which is present at a position lower than that of the suction member, constructed to be vertically movable, tapered at its tip, brought close to/inserted into an adjacent reaction cuvette earlier than the suction member during a downward movement of the rinse mechanism, and adapted to adjust an inserting position of the suction member to a correct position if the stopping position of the reaction cuvette deviates. Additionally, in order to achieve the above object, in the above automatic analyzer according to the present invention, the reaction cuvette includes a convex (or concave) positioning guide pin (or tapered hole), whereas the positioning member has a concave (or convex) tapered hole (or guide pin); wherein the positioning member is present at a position lower than that of the suction member, constructed to be vertically movable, and adapted to adjust an inserting position of the suction member to a correct position if, during a downward movement of the rinse mechanism, the convex (or concave) section of the reaction cuvette and the concave (or convex) section of the positioning member are brought close to/inserted into each other earlier than the suction member is inserted into the reaction cuvette and thus the stopping position of the reaction cuvette deviates. 
     According to the present invention, a highly reliable automatic analyzer can be provided that allows a rinse water suction member to be reliably inserted into a reaction cuvette during rinsing thereof and adjusts an inserting position of the suction member to a correct position even if the stopping position of the reaction cuvette deviates. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing a state in which rinse water is not suctioned in a rinse mechanism based on a conventional technique; 
         FIG. 2  is a diagram showing a state in which rinse water is suctioned in the rinse mechanism of  FIG. 1 ; 
         FIG. 3  is a diagram showing a state in which rinse water is suctioned in the rinse mechanism of  FIG. 1  that includes a suction member tapered at its tip; 
         FIG. 4  is a diagram of a tapered entrance of a reaction cuvette; 
         FIG. 5  is a diagram showing a state in which rinse water is not suctioned in a first embodiment of the present invention; 
         FIG. 6  is a diagram showing a state in which rinse water is suctioned in the first embodiment of the present invention; 
         FIG. 7  is a diagram showing a state in which rinse water is not suctioned in a second embodiment of the present invention; and 
         FIG. 8  is a diagram showing a state in which rinse water is suctioned in the second embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The object of providing a highly reliable automatic analyzer that comprises a rinse mechanism adapted so that a suction member is reliably inserted into a reaction cuvette without deterioration of rinse liquid suction performance and without dimensional increases of the reaction cuvette or of the apparatus was realized by adding a positioning member to the nozzle support jig of the rinse mechanism. 
     First Embodiment 
       FIGS. 1 and 2  are schematic block diagrams of a conventional rinse mechanism. 
     Referring to  FIG. 1 , a reaction cuvette  1  is installed on a reaction disk. The rinse mechanism includes elements such as a rinse nozzle  2 , a suction member  3  connected to a tip of the rinse nozzle  2 , a nozzle support jig  4  for supporting the rinse nozzle  2 , an arm  5  fastened to the nozzle support jig  4 , a feed screw  6  and motor  7  for moving the arm  5  vertically, and a cushioning spring  8  for the rinse nozzle  2 .  FIG. 1  shows the state of the rinse mechanism and reaction cuvette existing when rinse water is not suctioned.  FIG. 2  shows the state of the rinse mechanism and reaction cuvette existing when rinse water is suctioned. In  FIG. 2 , downward movement of the arm  5  via the motor  7  and the feed screw  6  also moves downward the nozzle support jig  4  fastened to the arm  5 . Thus, the rinse nozzle  2  and suction member  3  connected to the nozzle support jig  4  are also moved downward and inserted into the reaction cuvette  1  that has been moved to a required rinsing position to suction/discharge the rinse water present in the reaction cuvette  1 . A clearance between the suction member  3  and an inner wall of the reaction cuvette  1  is very small, so if a stopping position of the reaction cuvette  1  deviates for reasons such as integrated dimensional errors of constituent parts, contact of the suction member  3  with the entrance of the reaction cuvette  1  is likely, which causes an alarm indicating an insertion failure and results in an operational stoppage of the automatic analyzer. To avoid contact between the suction member  3  and the reaction cuvette  1 , an inserting position of the suction member  3  can be adjusted conceivably by providing the tip of the suction member with a taper  3   a  as shown in  FIG. 3  or by providing the entrance of the reaction cuvette  1  with a taper  1   a  as shown in  FIG. 4 . If the suction member  3  is provided with the taper  3   a  as shown in  FIG. 3 , however, the rinse liquid is liable to remain unsuctioned in the reaction cuvette since the clearance between the tapered section and the inner wall of the reaction cuvette will increase. If the entrance of the reaction cuvette  1  is provided with the taper la as shown in  FIG. 4 , since the distance from the starting position of the taper to the ending position thereof needs to be at least about 0.5 mm, the reaction cuvette will be 2.5 to 3.5 mm wide, which is about 1.4 times as wide as in conventional techniques. This increase in the width of the reaction cuvette will increase the spaces between the reaction cuvette and its adjacent reaction cuvettes, hence necessarily increasing the size of the reaction disk on which to set up the cuvettes, and posing problems associated with miniaturization of both the cuvettes and the apparatus. 
     Accordingly, the operation of a first embodiment of the present invention for solving the above problems will be described using  FIGS. 5 ,  6 ,  7 , and  8 . 
     Referring to  FIG. 5 , a positioner includes a positioning member  9 , a shaft  9   a , a spring  9   b , and a retainer  9   c , is installed through a nozzle support jig  10 , and can be moved vertically. Also, the section at which the nozzle support jig  10  is fastened to an arm  5  has an added movable part  11  so that when a reaction cuvette  1  and the positioning member  9  are guided toward each other, the nozzle support jig  10  can be moved slightly in a horizontal direction. A relationship in position between the positioning member  9  and a suction member  3  is the same as a positional relationship of the reaction cuvette  1  to its adjacent reaction cuvettes. The positioning member  9  when rinse water is not suctioned is positioned to be lower than the suction member  3 .  FIG. 6  shows a state of the rinse mechanism existing when rinse water is suctioned. In this state, as in the state of  FIG. 2 , the arm  5 , the nozzle support jig  10 , a rinse nozzle  2 , and the suction member  3  move downward. At this time, although the positioning member  9 , the shaft  9   a , the spring  9   b , and the retainer  9   c  also descend, since the positioning member  9  is present at a position lower than that of the suction member  3 , the positioning member  9  approaches the reaction cuvette  1  earlier. The positioning member  9 A descends to a reaction cuvette position  1   c  or reaction cuvette position  1   d  adjacent to a reaction cuvette position  1   b  into which the suction member  3  is inserted. The positioning member  9 A has a tapering tip, and a wide clearance is formed between the inner wall of the reaction cuvette  1  and the tip of the positioning member  9 . The positioning member  9 A is therefore adapted to easily enter the reaction cuvette  1  and adjust an inserting position of the suction member  3  to a correct position. At this time, the movable part  11  assists the nozzle support jig  10  in moving horizontally. Since the suction member  3  and the reaction cuvette  1  are not changed in shape or size, the suction member is thus reliably inserted into the reaction cuvette without deterioration of rinse liquid suction performance and without dimensional increases of the reaction cuvette or of the apparatus. Therefore, high reliability of the automatic analyzer can be achieved. 
       FIGS. 7 and 8  illustrate another embodiment of the present invention. Referring to  FIG. 7 , the reaction cuvette  1  includes a convex (or concave) positioning guide pin (or tapered hole)  12 . Also, a positioning member  13  has a concave (or convex) tapered hole (or guide pin)  13   a  at a position matching a positional relationship of the positioning guide pin  12 . As in  FIG. 5 , when rinse water is not suctioned, the positioning member  13  is positioned to be lower than the suction member  3 .  FIG. 8  shows a state of the rinse mechanism when rinse water is suctioned. In this state, as in the state of  FIG. 2 , the arm  5 , the nozzle support jig  10 , the rinse nozzle  2 , and the suction member  3  move downward. At this time, although the positioning member  13 , the shaft  9   a , the spring  9   b , and the retainer  9   c  also descend, since the positioning member  13  is present at a position lower than that of the suction member  3 , the positioning member  13  approaches the reaction cuvette  1  earlier. The positioning member  13  descends to the positioning guide pin  12  adjacent to the reaction cuvette position  1   b  into which the suction member  3  is inserted. At that time, the concave (or convex) tapered hole (or guide pin)  13   a  is inserted at the position matching the positional relationship of the convex (or concave) positioning guide pin  12  provided on the reaction cuvette  1 . In addition, as in the above embodiment, a wide clearance is formed between the positioning guide pin  12  and the concave (or convex) tapered hole  13   a  in the positioning member  13 . Hence, the positioning member  13  can easily enter the reaction cuvette  1  and works together with the positioning pin  12  to adjust the inserting position of the suction member  3  to the correct position. At this time, the movable part  11  assists the nozzle support jig  10  in moving horizontally. Since the suction member  3  and the reaction cuvette  1  are not changed in shape or size, the suction member  3  is thus reliably inserted into the reaction cuvette  1  without deterioration of rinse liquid suction performance and without dimensional increases of the reaction cuvette  1  or of the apparatus. Therefore, high reliability of the automatic analyzer can be achieved.