Patent Publication Number: US-2013243653-A1

Title: Automatic analysis apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to automatic analysis apparatuses which make qualitative and quantitative analyses of biologic samples such as blood and urine and more particularly to improvement of an automatic analysis apparatus which uses a piercing type liquid container. 
     BACKGROUND ART 
     Typically an automatic analysis apparatus which makes an analysis of biologic samples such as blood and urine on a plurality of items can be loaded with a plurality of reagent containers containing a first reagent and a third reagent to be mixed with a sample to induce reaction. In recent years, the number of analysis items has been dramatically increasing and in response to this, many kinds of reagents are becoming commercially available. 
     Against this background, several types of reagent containers which contain reagents have also become commercially available and in order to prevent condensation of a reagent due to its evaporation, there is an increasing tendency to use a piercing type reagent container which has a reagent container cap to prevent deterioration of the reagent. 
     An automatic analysis apparatus which uses a piercing type reagent container like this is described, for example, in Patent Literature 1. Paying attention to the fact that a larger portion of the dispensing nozzle are in contact with the cap when a piercing type reagent container is used, Patent Literature 1 proposes to reduce nozzle cleaning liquid and cleaning time by adjustment of the dispensing nozzle cleaning area. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP-A. No. 2002-162403 
     SUMMARY OF INVENTION 
     Technical Problem 
     When a dispensing nozzle breaks into the pierced piecing cap of a reagent container for reagent dispensing, the reagent container piercing cap and the dispensing nozzle are brought into contact with each other and at that time, dispensing nozzle abnormal descent detection may occur due to the descent velocity of the dispensing nozzle, the material or shape of the cap and so on. Dispensing nozzle abnormal descent detection is a function which stops the descent of the dispensing nozzle if the tip of the dispensing nozzle collides with a foreign object such as the apparatus top cover, in order to prevent damage to the dispensing nozzle and injury to the operator. 
     In addition, it has been found that when the dispensing nozzle ascends from the reagent container, step-out of the dispensing nozzle ascent motor and top dead point abnormality may occur and an amount of reagent attached to the dispensing nozzle tip in excess of an allowable amount may splash at the moment the dispensing nozzle leaves the piercing cap. It is considered that this kind of problem arises not only in reagent containers but also a similar problem arises in sample containers which contain liquid samples. 
     An automatic analysis apparatus is designed with an estimated safety factor to prevent these problems; however, it is desirable to design it with higher safety in case of unexpected circumstances such as cap material deterioration and nozzle tip deformation. 
     Therefore, the present invention has an object to provide a highly reliable automatic analysis apparatus using a piercing type liquid container which reduces the influence on analysis performance of dispensing nozzle alarms, reagent splashing and the like even if unexpected circumstances such as cap material deterioration and nozzle tip deformation occur. 
     Solution to Problem 
     In order to achieve the above object, the present invention is characterized in that in an automatic analysis apparatus including: 
     a liquid container with a piercing type cap for containing a liquid, 
     a dispensing nozzle for penetrating the cap and sucking the liquid contained in the liquid container, and 
     a nozzle vertical movement mechanism for moving up and down the dispensing nozzle, 
     a control device for the nozzle vertical movement mechanism which lowers the moving velocity of the dispensing nozzle in a zone where a tip of the dispensing nozzle passes through the cap is provided so that the dispensing nozzle passes through the cap at a low velocity. 
     The further features of the present invention to achieve the above object will appear from the following embodiment described below. 
     Advantageous Effects of Invention 
     In an automatic analysis apparatus using a piercing type liquid container, even if unexpected circumstances such as cap material deterioration, nozzle tip deformation and so on occur, the velocity of the dispensing nozzle passing through the cap can be decreased, so that the influence on analysis performance of dispensing nozzle alarms in the sampling mechanism, reagent splashing and so on is reduced, making it possible to realize a highly reliable automatic analysis apparatus. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a general structural diagram of an automatic analysis apparatus to which the present invention is applied. 
         FIG. 2  is a structural diagram of a reagent sampling mechanism according to a working example of the present invention. 
         FIG. 3  is a diagram illustrating the range of movement of a reagent sampling mechanism according to a working example of the present invention. 
         FIG. 4  is a diagram illustrating the control positional relation of a dispensing nozzle according to a working example of the present invention. 
         FIG. 5  is a flow chart of control position measurement of a dispensing nozzle according to a working example of the present invention. 
         FIG. 6  is a control position data map of a dispensing nozzle according to a working example of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Next, an embodiment of the present invention will be described in detail using an illustrated working example. In the working example described below, as a piercing type liquid container to contain a liquid, an example of a reagent container to contain a reagent will be given, but not only a container to contain a reagent but also a piercing type sample container to contain a sample may be embodied similarly. 
       FIG. 1  is a general structural diagram which shows an example of an automatic analysis apparatus to which the present invention is applied. 
     This working example includes a sample disk  2  on which a sample container  1  containing a sample to be analyzed is loaded, a specimen sampling mechanism  5  for sucking the sample from the sample disk  2  and dispensing the sample to a reaction disk  4  holding a plurality of reaction cells  3  for reaction and photometry, a piercing type reagent container  6  filled with a first, a second and a third reagent to be mixed with the sample for reaction, a reagent disk  7  for storing a plurality of reagent containers  6  and keeping them cool, an R 1  reagent sampling mechanism  8  for the first reagent which dispenses the reagent from the reagent container  6  to the reaction disk  4 , an R 2 / 3  reagent sampling mechanism  9  for the third reagent, and a photometric section  10  for photometric measurement of a liquid mixture of the sample and reagent which react with each other on the reaction disk  4 . The operation control of the tables and mechanisms is performed by a control device (not shown in the figure) which includes a computer and so on. 
       FIG. 2  is a structural diagram of a reagent sampling mechanism according to a working example of the present invention. A dispensing nozzle  31  provided in the reagent sampling mechanism  8 ,  9  is operated by a combination of horizontal and vertical movements. 
     A horizontal movement is made by a combination of the rotation of a first arm  29  and the rotation of a second arm  30 . The first arm  29  is rotated by transmitting the rotary driving force of a first arm drive motor  20  through a belt  21  for the first arm to a first arm shaft  32  and the first arm  29 . 
     The second arm  30  is done by transmitting the rotary driving force of a second arm drive motor  22  to a second arm shaft  33  and further transmitting it through a belt  26  for the second arm to a shaft  27  which is located in the first arm and serves as the center of rotation of the second arm. 
       FIG. 3  shows the range of movement of a reagent sampling mechanism and the range of access  35  of the reagent dispensing nozzle  31  is a wide range which combines the range of movement  36  of the first arm and the range of movement  37  of the second arm. 
     For vertical movement, the rotation of a vertical movement drive motor  23  is transmitted through a vertical movement belt  24  and a slider  25  to the first arm shaft  32  so that the first arm  29  and the second arm  30  move up and down simultaneously. 
     An opening through which the dispensing nozzle  31  passes through the reagent container piercing cap  34  when dispensing the reagent can be made in the piercing cap  34  of the piercing type reagent container  6  by an opening nozzle  28 . 
     The reagent sampling mechanism  8 ,  9  has an abnormal descent detection mechanism which detects that the reagent dispensing nozzle  31  collides with a foreign object during its descent. If the tip of the dispensing nozzle  31  collides with a foreign object, this abnormal descent detection mechanism detects by a photo-coupler (photo-interrupter) or the like that it has moved to a position above a prescribed position. 
     As the abnormal descent detection mechanism is activated, the descending movement of the nozzle is stopped to prevent damage to the nozzle and injury to the operator. Also when abnormal descent detection is made, the nozzle height can be calculated from the pulse number using a pulse motor or the like for the drive motor  23 . 
     If a DC motor is used as the drive motor  23 , it can be calculated similarly by providing a pulse encoder in its drive shaft and counting generated pulses. 
     In addition, an ordinary liquid level sensor which detects, based on electrical conductivity or change in electrostatic capacitance, that the dispensing nozzle  31  comes into contact with the reagent liquid surface in the reagent container  6  is also provided. 
     The height of the piercing cap  34  of the reagent container  6  can be calculated from the height dimension of the surface of loading onto the reagent disk  7  and the height dimension of the piercing cap  34  and the amount of descent of the dispensing nozzle  31  until the tip of the dispensing nozzle  31  provided in the reagent sampling mechanism  8 ,  9  comes into contact with the piercing cap  34 . 
     However, it is considered that the height of the piercing cap  34  of the reagent container  6  placed on the circumference of the reagent disk  7  and the height of the reagent liquid surface vary with individual reagent containers, depending on the dimensional accuracy and assembly error of individual components, strain due to the weight of the reagent container  6  and so on. 
       FIG. 4  shows the positional relation for control of the dispensing nozzle according this working example. In the figure, Z denotes the dimension of maximum movement of the dispensing nozzle, A and B denote low velocity zones, X denote the dimension of piercing cap-reagent liquid level dimension, α denotes the amount of immersion, C denotes the amount of descent to the reagent container piercing cap, and D denotes the dimension of piercing cap-reagent liquid level. In order to control the descent of the dispensing nozzle  31 , it is necessary to find these positions and dimensions in relation to the amount of descent of the dispensing nozzle  31 , though the positional relation varies with individual reagent containers for the abovementioned reasons. 
     Therefore, first, a working example in which the positional relation among these is measured for each reagent container and stored will be described referring to the control position measurement flow of the dispensing nozzle in  FIG. 5  and the control position data map in  FIG. 6 . 
     The automatic analysis apparatus is started up and before starting analysis, reagent containers are loaded on the reagent disk (Step  51 ), then, regarding the piercing cap height of the reagent containers placed on the circumference, the position where the sensor turns on for a reagent container (descent pulse number C) is measured for all the reagent containers by moving down the dispensing nozzle  31  and using abnormal descent detection and stored in the control position data map in  FIG. 6  (Step  52 ). 
     Next, the dispensing nozzle  31  is moved down and regarding the height of the reagent liquid surface in the reagent container, the liquid level height (descent pulse number D) is measured using a liquid level sensor of the electrostatic capacitance type and stored in the control position data map in  FIG. 6  (Step  53 ). The pulse number which is obtained by adding a fixed pulse number for the amount of immersion α to the pulse number D is the maximum descent pulse number Z, which is stored in the control position data map in  FIG. 6  (Step  54 ). 
     In order to determine low velocity zones for the descent velocity of the dispensing nozzle in the vicinity of the piercing cap, low velocity start pulse number V is calculated by subtracting a fixed pulse number from the pulse number to reach the piercing cap and conversely low velocity end pulse number Y is calculated by adding a fixed pulse number to the pulse number to reach the piercing cap and they are stored in the control position data map in  FIG. 6  (Steps  55 ,  56 ). The positional data on all the reagent containers (control pulse numbers) is calculated in this way to determine low velocity zones (Step  57 ) so that the subsequent vertical movements of the dispensing nozzle  31  are controlled according to the data stored in the control position data map in  FIG. 6 . 
     Here the amount of immersion α is the distance required for the tip of the dispensing nozzle  31  to get into the reagent liquid in order to ensure that the reagent is sucked in. Since the liquid level sensor generates a detection signal when the dispensing nozzle  31  comes into contact with the liquid, if a piercing type reagent container  6  is used, it also generates a detection signal upon contact of liquid attached to the piercing cap  34 . In this case, the actual liquid surface is located below the piercing cap  34 , so in the descending movement of the reagent sampling mechanism  8 ,  9 , control is performed so as to ignore a detection signal during the descent down to the piercing cap  34 . 
     In addition, by storing, for each reagent container, the remaining pulse number obtained by subtracting the number of pulses sent to the pulse motor until detection of the liquid surface, from the total number of pulses sent to the pulse motor to move the dispensing nozzle  31  down to the lowest descent point, when dispensing the same reagent next time, the descending movement of the dispensing nozzle  31  can be controlled at high velocity until the stored remaining pulse number. 
     When the reagent sampling mechanism  8 ,  9  is going to dispense the reagent, control is performed so that in the specific zones A and B before and after the dispensing nozzle  31  descends and passes through the piercing cap  34 , the descent velocity of the dispensing nozzle  31  is temporarily lowered (velocity: 0.02 m/s) and after it passes over the zones, the descent velocity is set to a normal velocity (velocity: 0.04 m/s). If the vertical movement drive motor  23  is a pulse motor, such high velocity movement and low velocity movement of the dispensing nozzle  31  can be achieved by changing its drive pulse rate according to the content of operation in the routine operation. 
     In the above example, by setting the velocity in the specific zones A and B to 50% of the normal velocity, priority is given to substantially reducing the frictional force generated when the dispensing nozzle  31  comes into contact with the piercing cap  34 , but it has been found that if priority should be given to treatment efficiency, a sufficient effect is produced even by about 70% of the normal velocity. 
     As mentioned so far, when the dispensing nozzle  31  descends and passes through the piercing cap  34 , the velocity is low in the low velocity zone A and after the piercing cap  34  is passed over, the low velocity is maintained in the low velocity zone B, and then it descends at the normal velocity for the distance X to the liquid surface (dimension X of low velocity zone-reagent liquid surface). Therefore, the frictional force generated when the dispensing nozzle  31  comes into contact with the piercing cap  34  is decreased and false abnormal descent detection can be decreased and also the load on the reagent sampling mechanism  8 ,  9  is reduced. 
     Furthermore, when the dispensing nozzle  31  ascends from the liquid surface, similarly it ascends from the liquid surface at the normal velocity for the distance X before it comes into contact with the piercing cap  34 , and passes through the piercing cap  34  while the low velocity is maintained for the distance B before it comes into contact with the piercing cap  34  and after passing over the distance A, the normal ascent velocity is restored. 
     Consequently, in the ascent of the dispensing nozzle  31  as well, the frictional force generated by contact of the dispensing nozzle  31  with the piercing cap  34  is decreased and step-out of the vertical movement drive motor  23  and false top dead point detection of the reagent sampling mechanism  8 ,  9  is reduced and also splashing of reagent liquid drops attached to the tip of the dispensing nozzle  31  outside the reagent container which occurs when the dispensing nozzle  31  comes into contact with the piercing cap  34  is also reduced. 
     Furthermore, the abovementioned working example has been described, taking a dispensing system for a reagent container to contain a reagent as an example; however, obviously not only a reagent container but even a piercing type sample container which contains a sample may be embodied similarly. 
     LIST OF REFERENCE SIGNS 
       1  . . . Sample container,  2  . . . Sample disk,  3  . . . Reaction cell,  4  . . . Reaction disk,  5  . . . Specimen sampling mechanism,  6  . . . Reagent container,  7  . . . Reagent disk,  8  . . . R 1  reagent sampling mechanism,  9  . . . R 2 / 3  reagent sampling mechanism,  10  . . . Photometric section,  20  . . . First arm drive motor,  21  . . . First arm belt,  22  . . . Second arm drive motor,  23  . . . Vertical movement drive motor,  24  . . . Vertical movement belt,  25  . . . Slider,  26  . . . Second arm belt,  27  . . . Shaft,  28  . . . Opening nozzle,  29  . . . First arm,  30  . . . Second arm,  31  . . . Dispensing nozzle,  32  . . . First arm shaft,  33  . . . Second arm shaft,  34  . . . Piercing cap,  35  . . . Range of access of the reagent dispensing nozzle,  36  . . . Range of movement of the first arm,  37  . . . Range of movement of the second arm