Abstract:
First and second racks each has fixed positions to hold sample tubes. First and second drawers slide into and out of the case, and that support the first and second racks, respectively. A tube set unit is provided in an area close to the first rack in the case. A tube transfer unit removes sample tubes from the first and second racks in the case and a controller that controls a transfer operation of the tube transfer unit. The first rack is supported by the first drawer such that the first rack leaves a transit location in the case behind the first drawer in the direction of the first drawer movement into the case. The controller controls the tube transfer unit to remove at least one sample tube from the second rack and transfers the tube to the tube set unit via a path traversing the transit location.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of application Ser. No. 14/580,888, filed on Dec. 23, 2014, which is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2013-272561, filed on Dec. 27, 2013, the entire contents of all of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a sample processing apparatus configured to perform processing on a sample held in a sample tube and a rack, which is used for the sample processing apparatus. 
       BACKGROUND 
       [0003]    There is known a sample analyzer in which a sample tube supply unit transfers one of multiple sample tubes held in a rack to a sample rack set unit and sets the sample tube in the sample rack set unit, a sample in the set sample tube is aspirated, and a measurement unit measures the aspirated sample (see Japanese Patent Application Publication No. 2007-139462). 
         [0004]    In the sample analyzer, in order for an operator to accommodate sample tubes in a rack, the operator needs to accommodate the sample tubes after waiting for an analyzer unit to complete measurement. In addition, it also takes some time to accommodate the sample tubes. For these reasons, some of facilities which have to process a large number of samples are subject to deterioration of sample processing performance of the device. 
       SUMMARY OF THE INVENTION 
       [0005]    The scope of the invention is defined by the appended claims, and not by any statements within this summary. 
         [0006]    A first embodiment relates to a sample processing apparatus. The sample processing apparatus according to this embodiment includes a case, first and second racks each configured to hold sample tubes, first and second drawers being capable of sliding into and out of the case, and configured to support the first and second racks, respectively, a tube set unit provided in an area close to the first rack in an entire area inside the case, a tube transfer unit configured to take out the sample tubes from each of the first and second racks in the case, and a controller configured to control a transfer operation of the tube transfer unit. The first rack in a state drawn in the case is supported by the first drawer so that the first rack leaves a first space on a side in a direction to which the first drawer is drawn into the case. The controller controls the tube transfer unit so that at least one of the sample tubes is taken out from the second rack and is transferred to the tube set unit through a transfer path passing the first space. 
         [0007]    A second aspect of the invention relates to a rack. The rack of this aspect may have a configuration in which tube holders are arranged in rows, and a space large enough to transfer at least a sample tube is provided between adjacent two of the rows. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]      FIG. 1  is a schematic diagram illustrating an outside appearance of a sample analyzer according to an embodiment; 
           [0009]      FIG. 2  is a schematic diagram illustrating a case where an inside of a case according to the embodiment is seen from above; 
           [0010]      FIG. 3A  is a perspective view illustrating a case where a rack according to the embodiment is seen from above; 
           [0011]      FIG. 3B  is a diagram illustrating an outside appearance of a sample tube according to the embodiment; 
           [0012]      FIGS. 3C to 3E  are cross-sectional diagrams of the sample tube according to the embodiment; 
           [0013]      FIGS. 4A to 4F  are perspective diagrams, each illustrating a case where the rack according to the embodiment is seen from below; 
           [0014]      FIG. 5A  is a schematic diagram illustrating forward and backward movements of a drawer according to the embodiment; 
           [0015]      FIG. 5B  is a diagram illustrating a configuration of the drawer according to the embodiment; 
           [0016]      FIG. 5C  is a diagram illustrating a case where a cut-apart rack set unit is seen from the front thereof; 
           [0017]      FIGS. 6A and 6B  are schematic diagrams, each illustrating a case where a vertical movement unit, holder, and stirrer mechanism are seen in the X-axis negative direction; 
           [0018]      FIG. 7A  is a flowchart illustrating lock processing on a drawer; 
           [0019]      FIG. 7B  is a flowchart illustrating transfer processing on a sample tube; 
           [0020]      FIG. 7C  is a diagram illustrating lamp lighting processing; 
           [0021]      FIG. 8A  is a diagram illustrating stirring processing by a stirrer mechanism according to the embodiment; 
           [0022]      FIGS. 8B to 8D  are diagrams, each illustrating aspiration processing by an aspiration unit according to the embodiment; 
           [0023]      FIG. 8E  is a conceptual diagram illustrating a configuration of a setting table stored in a hard disk according to the embodiment; 
           [0024]      FIG. 9  is a block diagram illustrating a configuration of a sample analyzer according to the embodiment; 
           [0025]      FIG. 10A  is a schematic diagram illustrating a case where a portion near two drawers according to the embodiment is seen from above; 
           [0026]      FIG. 10B  is a diagram illustrating a path seen in the X-axis direction in which sample tubes held in the front row of a rack according to the embodiment are transferred by a tube transfer unit; 
           [0027]      FIG. 10C  is a diagram illustrating a path seen in the X-axis direction in which sample tubes held in the rear row of the rack according to the embodiment are transferred by the tube transfer unit; 
           [0028]      FIGS. 11A to 11D  are diagrams, each illustrating a path in which sample tubes held in a right rack according to the embodiment are transferred by the tube transfer unit; 
           [0029]      FIGS. 12A to 12D  are diagrams, each illustrating a path in which sample tubes held in a left rack according to the embodiment are transferred by the tube transfer unit; 
           [0030]      FIGS. 13A to 13D  are diagrams, each illustrating a path in which sample tubes held in the left rack according to a modified embodiment are transferred by a tube transfer unit; 
           [0031]      FIGS. 14A to 14D  are diagrams, each illustrating a path in which sample tubes held in a rack according to the modified embodiment are transferred by the tube transfer unit; and 
           [0032]      FIGS. 15A to 15D  are diagrams, each illustrating a path in which sample tubes held in the rack according to the modified embodiment are transferred by the tube transfer unit. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    One embodiment is a sample analyzer configured to examine and analyze blood. Hereinafter, a sample analyzer according to the embodiment is described by referring to drawings. 
         [0034]      FIG. 1  is a diagram illustrating an outside appearance of sample analyzer  1  according to the embodiment. 
         [0035]    Sample analyzer  1  includes main body  2  and display input unit  3 , which is a touch panel display. Main body  2  is covered with case  2   a  and is provided with power button  11  configured to operate a power source of sample analyzer  1 , start button  12 , stop button  13 , two panels  21 , and two lamps  22  on the front side of case  2   a . Drawers  30  (see,  FIG. 2 ) are provided respectively on the back sides of two panels  21 . Two lamps  22  indicate states of corresponding drawers  30 . Openable/closable door  23  is provided on the front side of the right side surface of case  2   a.    
         [0036]    When continuously processing multiple samples (hereinafter, referred to as “sampler processing”), an operator pulls drawer  30  by pulling panel  21 , sets a rack holding sample tubes into drawer  30 , and then pushes start button  12 . In addition, preferably, when processing one sample (hereinafter referred to as “manual processing”), the operator opens door  23  and sets sample tubes into tube set unit  71  (see,  FIG. 2 ) inside case  2   a  and pushes start button  83  (see,  FIG. 2 ) inside case  2   a.    
         [0037]      FIG. 2  is a schematic diagram illustrating a case where the inside of case  2   a  is seen from above. 
         [0038]    Main body  2  includes two drawers  30  configured to set racks R 1  to R 6  (see,  FIG. 3A ), transmission sensors  41  configured to respectively detect two drawers  30  being set in case  2   a  in a closed state, holes  42  configured to respectively fix two drawers  30 , tube transfer unit  50  configured to transfer sample tubes T 1  to T 3  (see,  FIG. 3B ), stirrer mechanism  60  configured to stir a sample by turning sample tubes T 1  to T 3  down, back-and-forth conveyance unit  70  configured to move sample tubes T 1  to T 3  in back and forth directions, transmission sensor  81  configured to detect whether or not a sample tube exists in back-and-forth conveyance unit  70 , barcode reader  82 , start button  83 , sample aspiration unit  210  configured to aspirate samples in sample tubes T 1  to T 3 , sample preparation unit  220 , detector  230 , and measurement samples. 
         [0039]    Referring to  FIGS. 3A to 5C , racks R 1  to R 6 , sample tubes T 1  to T 3 , and drawers  30  are described. 
         [0040]      FIG. 3A  is a perspective diagram illustrating a case where racks R 1  to R 6  are seen from above. It is to be noted that in  FIG. 3A , coordinate axes illustrated in  FIG. 2 , which is used when racks R 1  to R 6  are set in drawers  30  are also illustrated. 
         [0041]    In the embodiment, as described later, six kinds of racks R 1  to R 6  are used according to kinds of sample tubes. As illustrated in  FIG. 3A , shapes of racks R 1  to R 6  are exactly same with one another when seen from above but shapes thereof which are seen from bottom are different from one another. The shapes of racks R 1  to R 6  are described by referring to  FIGS. 4A to 4F  later. 
         [0042]    To allow 10 sample tubes T 1  to T 3  to be held vertically, 10 holders Ra are formed in racks R 1  to R 6 , and 10 holders Ra are formed so that each 5 holders Ra are arrayed in a double row in front and rear sides. As illustrated in  FIG. 3A , positions of 10 holders Ra are referred to as holding position n 1  to n 10  for convenience. Also, the top surface of racks R 1  to R 6  are parallel with the X-Y plane, and intermediate portion Rb is formed between the row of holding positions n 1  to n 5  and the row of holding positions n 6  to n 10 . In addition, dent portion Rc that dents inside the periphery thereof is formed on the rear side (the Y-axis positive side) of the lower end of rack R 1  to R 6 . 
         [0043]      FIG. 3B  is a diagram illustrating an outer appearance of sample tubes T 1  to T 3 . 
         [0044]    Sample tubes T 1  to T 3  include body portion Ta, lid portion Tb, and barcode label Tc. Body portion Ta is a tubular container configured of translucent glass or synthetic resin and has an opening formed on an upper end thereof. Body portion Ta holds a sample and the opening in the upper end is tightly sealed with lid portion Tb. Lid portion Tb is configured to allow piercer  211  (see  FIG. 2 ) to pass therethrough. Barcode label Tc includes a barcode including sample ID printed thereon. Barcode label Tc is adhered to the side surface of body portion ta. 
         [0045]    Each of  FIGS. 3C and 3E  is a cross-sectional diagram of sample tubes T 1  to T 3 . For example, sample tubes T 1  to T 3  are used as blood-collecting vessels. 
         [0046]    Bottom surface Td is formed on a lower end of an inner side of body portion Ta, and the positions of bottom surfaces Td of sample tubes T 1  to T 3  become higher in the order of sample tubes T 1  to T 3 . Accordingly, volumes of samples containable in sample tubes T 1  to T 3  become smaller in the order of sample tubes T 1  to T 3 . 
         [0047]    Each of  FIGS. 4A to 4F  is a perspective diagram illustrating a case where racks R 1  to R 6  are seen from bottom (Z-axis negative side). 
         [0048]    On the lower end of racks R 1  to R 6 , in addition to recessed portion Rc illustrated in  FIG. 3A , projection portion Rd which outwardly projects from the periphery thereof is formed on the opposite side of recessed portion Rc (the Y-axis negative side of the lower end of racks R 1  to R 6 ). 
         [0049]    Also, on the lower surface of racks R 1  to R 6 , projection portion Re is formed. A lower end of projection portion Re is positioned higher than the lower end of racks R 1  to R 6 . There are three portions where projection portion Re is to be formed, and projection portion Re is formed in at least one position among these positions. Specifically, projection portion Re is formed in each of the three positions in rack R 1 , and projection portions Re are formed in the center and a position on the X-axis positive side in rack R 2 , projection portions Re are formed in positions on the X-axis positive side and the X-axis negative side in rack R 3 . In addition, projection portions Re are formed in the center and a position on the X-axis negative side in rack R 4 , and projection portion Re is formed in the center in rack R 5 , and projection portion Re is formed in a position on the X-axis negative side. 
         [0050]    Here, samples according to the embodiment include regular samples whose analysis is not particularly in harry (hereinafter, referred to as “regular sample”) and samples whose analysis has to be performed preferentially to the regular samples (hereinafter, referred to as “priority sample”). Also, three kinds of above-described sample tubes T 1  to T 3  are used as sample tubes, and any one of the regular samples and the priority samples is held in each of the sample tubes T 1  to T 3 . Accordingly, in the present embodiment, there are sample tubes T 1  to T 3  holding the regular samples, and sample tubes T 1  to T 3  holding the priority samples. As a result, there are six kinds of sample tubes in combination. 
         [0051]    Also, in the embodiment, a rack to be used is determined for each of the six kinds of the sample tubes. Sample tubes T 1  to T 3  holding regular samples are set only in racks R 1  to R 3 , respectively, and sample tubes T 1  to T 3  holding priority samples are set only in racks R 4  to R 6 , respectively. Hereinafter, racks R 1  to R 3  are collectively referred to as a “regular rack” and racks R 4  to R 6  are collectively referred to as a “priority rack.” In this manner, racks R 1  to R 6  in which sample tubes T 1  to T 3  are set according to the above rules are set in drawer  30  which is pulled out forwardly by an operator. 
         [0052]      FIG. 5A  is a schematic diagram illustrating the back and forth movements of drawer  30 . 
         [0053]    Panel  21  is connected with a front end (end portion on the Y-axis negative side) of drawer  30 , which is moved back and forth along the panel  21  when an operator moves panel  21  back and forth. Also, rack set unit  300  is formed in drawer  30  for installing racks R 1  to R 6 . When drawer  30  is moved back and forth, rack set unit  300  is also moved between a loaded position in which the rack is loaded in case  2   a  and a drawn position in which the rack is drawn out from case  2   a.    
         [0054]    When drawer  30  is drawn out and rack set unit  300  is positioned in the drawn position, the operator may set the rack in rack set unit  300  and may also take out the rack set in rack set unit  300 . Also, when rack set unit  300  is positioned in the loaded position, processing is performed with mechanisms inside case  2   a  on the sample tubes held in the rack set in rack set unit  300 . 
         [0055]      FIG. 5B  is a diagram illustrating the configuration of drawer  30 . Here, for convenience&#39;s sake,  FIG. 5B  omits illustration of flange portion  31  and bar member  32  (see  FIG. 2 ), which are to be described later. 
         [0056]    Rack set unit  300  is formed in a position near the center of drawer  30 , and the bottom surface of rack set unit  300  is formed so as to be lower by one step than the upper surface of drawer  30 . In the front end and rear end of rack set unit  300 , dent portion  310  and projection portion  320  are formed so as to respectively engage with projection portion Rd and dent portion Rc of the rack set in rack set unit  300 . The upper surfaces of projection portions  311  to the right and left of dent portion  310  are lower than the upper surface of drawer  30 , and the upper surface of projection portion  320  is higher than the upper surface of drawer  30 . Also, projection portion  330  is formed in the center of rack set unit  300 . Gaps  331  to  333  corresponding to three projection portions Re of the rack set in rack set unit  300  are formed in projection portion  330 . 
         [0057]      FIG. 5C  is a diagram illustrating the case where rack set unit  300  taken out by C 1 -C 2  in  FIG. 5B  is seen from front thereof (in the Y-axis positive direction). 
         [0058]    In projection portion  330 , transmission sensors  341  to  343  are provided to sandwich gaps  331  to  333  therebetween. For example, when rack R 1  is set in rack set unit  300 , three projection portions Re formed in rack R 1  are positioned in gaps  331  to  333 . Accordingly, when it is detected by detection signals of sensors  341  to  343  that projection portion Re is positioned in at least one of gaps  331  to  333 , it is recognized that the rack is set in rack set unit  300 . Also, hard disk  270  (see,  FIG. 9 ) in main body  2  stores the configuration of projection portion Re of racks R 1  to R 6  illustrated in  FIGS. 4A to 4F . With this, the rack set in rack set unit  300  may be identified as one of racks R 1  to R 6 . 
         [0059]    Also, when the rack is placed in rack set unit  300  so as to reverse the back and forth directions, the bottom surface of the rack including projection portion Rd and dent portion Rc comes in contact with projection portions  311 ,  320 , which causes the rack to tilt in the back and forth directions. Accordingly, the operator may realize that the placement direction of the rack is wrong. It is to be noted in the embodiment that even when the rack is placed so as to reverse the back and forth directions, projection portion Re and rack set unit  300  are configured so as not to bring projection portion Re into contact with projection portion  330 . 
         [0060]    Return to  FIG. 2 . When a rack is set in drawer  30  and drawer  30  is pushed to the rear side thereof, flange portion  31  provided on the rear side of drawer  30  is positioned in a gap between transmission sensors  41  provided inside case  2   a . Accordingly, it is detected based on detection signals of sensors  41  that drawer  30  is drawn out and drawer  30  is closed. When transfer of sample tubes is started on the rack set in drawer  30  by tube transfer unit  50  after the rack is set in drawer  30  and this drawer  30  is closed, drawer  30  is locked so that the rack is not forwardly pulled out by accident. Specifically, bar member  32  provided in drawer  30  is driven by an unillustrated driver in the Y-axis direction and is inserted into hole  42  provided inside case  2   a , so that drawer  30  is limited to be forwardly pulled out. Also, bar member  32  is driven in a direction opposite to the direction in which it is locked, so that the lock of drawer  30  is released so that drawer  30  can be forwardly pulled out. 
         [0061]      FIG. 7A  is a flowchart illustrating lock processing on drawer  30 . This processing is performed by CPU  201  to be described later. 
         [0062]    Grippers  541 ,  542  (see,  FIG. 2 ) of tube transfer unit  50  start moving from an initial position on the left-rear side thereof inside case  2  and a transfer operation of sample tubes on the rack set in drawer  30  is started (S 101 : YES), drawer  30  is locked (S 102 ). 
         [0063]    Subsequently, the sample tubes held by the rack are sequentially taken out by tube transfer unit  50  from the rack and transferred. Then, as is described later, stirring processing and aspiration processing are performed on samples held in the taken-out sample tubes. When the processing is terminated on the samples, the sample tubes are returned to the original holding positions of the original rack. In this manner, when the processing is terminated on all the samples on the rack (S 103 : YES), the processing stands by until grippers  541 ,  542  of tube transfer unit  50  retracts to the position where the grippers do not come in contact with drawer  30  which is forwardly pulled out (S 104 ). When grippers  541 ,  542  are retracted (S 104 : YES), the lock of this drawer  30  is released (S 105 ). In this manner, the lock processing on drawer  30  is terminated. 
         [0064]    Return to  FIG. 2 . Tube transfer unit  50  includes motors  51 ,  52 , belts  53 ,  54 , and movement body  500 . 
         [0065]    Movement body  500  includes right-left movement unit  510 , front-back movement unit  520 , up-down movement unit  530 , and holder  540 . Right-left movement unit  510  is movable in the right and left directions while being supported by a guide (unillustrated), which is provided in case  2   a  and extends in the right and left directions. Front-back movement unit  520  is movable in the back and forth directions while being supported by a guide (unillustrated) which is provided in right-left movement unit  510  and extends in the back and forth directions. Up-down movement unit  530  is moved relative to front-back movement unit  520  in the up and down directions by a cylinder (unillustrated) provided in front-back movement unit  520 . Holders  540  are configured to be capable of holding sample tubes T 1  to T 3  between the back and forth directions, and are supported by up-down movement unit  530  to be rotatable about the Y-axis as a rotation axis. 
         [0066]    Motor  51  drives belt  53  installed around pulleys provided on the right and left sides of case  2   a  in the right and left directions. Attachment stay  511  of right-left movement unit  510  is fixed in the belt  53 . Accordingly, the right-left movement unit  510  becomes movable in the right and left directions along with the belt  53 . Motor  52  drives belt  54  installed in pulleys provided on the right and left sides of case  2   a  in the right and left directions. One portion of belt  54  is forwardly folded by pulleys  512  provided in right-left movement unit  510  and is installed on the pulleys  513  provided in the front side of right-left movement unit  510 . Attachment stay  521  of front-back movement unit  520  is fixed in belt  54  between pulleys  512 ,  513 . Accordingly, front-back movement unit  520  becomes movable in the back and forth directions along with belt  54 . Thus, holders  540  become freely movable in the X, Y, and Z directions in case  2   a.    
         [0067]    Stirrer mechanism  60  includes motor  61 , shaft  62  which is connected with motor  61  and extends in the Y-axis direction, and abutting member  63  fixed in shaft  62 . The sample tube, which is held by grippers  541 ,  542  and is positioned in position P 1  is pushed by abutting member  63  and is turned down, so that a sample inside the sample tube is stirred. 
         [0068]      FIGS. 6A and 6B  schematic diagrams, each illustrating the case where up-down movement unit  530 , holder  540 , and stirrer mechanism  60  are seen in the X-axis direction. 
         [0069]    Up-down movement unit  530  includes base board  531 , shaft  532  fixed to base board  531 , cylinder  533  fixed to base board  531 , plate member  534  provided in an end portion on the Y-axis negative side of rod  533   a  of cylinder  533 , flange portion  534   a  provided in an upper end of plate member  534 , and transmission sensors  535  provided in base board  531  on the Y-axis positive side of flange portion  534   a.    
         [0070]    Holder  540  includes grippers  541 ,  542  provided in shaft  532  to be rotatable about shaft  532  as a rotation axis, and spring  543  provided between grippers  541 ,  542 . Gripper  541  is provided in shaft  532  so as not to move in the Y-axis direction, and the upper end of gripper  542  is positioned on the Y-axis negative side of plate member  534 . 
         [0071]    When force is not added to rod  533   a  in the Y-axis negative direction, gripper  542  is pulled in the Y-axis positive direction with contractile force of spring  543  and the lower ends of grippers  541 ,  542  come in contact with each other. At this time, plate member  534  is pushed in the Y-axis positive direction by the upper end of gripper  542  and flange portion  534   a  is positioned in the gap between sensors  535 . Accordingly, it is detected that the lower ends of grippers  541 ,  542  come in contact with each other, that is, the sample tube is not gripped by holder  540 . 
         [0072]    When cylinder  533  pushes rod  533   a  in the Y-axis negative direction, as illustrated in  FIG. 6A , plate member  534  moves in the Y-axis negative direction. At this time, plate member  534  pushes the upper end of gripper  542  in the Y-axis negative direction with contractile force of spring  543 , and flange portion  534   a  moves in the Y-axis negative direction of sensor  535 . 
         [0073]    In order for grippers  541 ,  542  to grip sample tubes T 1  to T 3 , grippers  541 ,  542  are firstly moved to the position of the sample tube (rack holding position) to be gripped in a state where grippers  541 ,  542  are opened, and lowered to a position at a predetermined height as illustrated in  FIG. 6A . Then, when the force of cylinder  533  to push rod  533   a  is weakened, gripper  542  moves in the Y-axis positive direction, and body portion Ta of the sample tube is gripped by grippers  541 ,  542  with the contractile force of spring  543  as illustrated in  FIG. 6B . Since the sample tube is between grippers  541 ,  542  at that time, gripper  542  stops at a predetermined position and flange portion  534   a  is not positioned in the gap between sensors  535 . Accordingly, it is detected that the holder  540  grips the sample tube. 
         [0074]    Accordingly, in an operation where grippers  541 ,  542  perform a gripping operation on each holding position of the rack, it can be detected that the sample tube is not held in this holding position if flange portion  534   a  is positioned in the gap between sensors  535 , whereas it can be detected that the sample tube is in this holding position if flange portion  534   a  is positioned outside the gap between sensors  535 . Then, when it is detected that the sample tube is not held in the gripping operation, the transfer operation of the sample tube to this holding position is stopped. 
         [0075]      FIG. 7B  is a flowchart illustrating the transfer processing on the sample tubes. This processing is performed by CPU  201  to be described later. 
         [0076]    When the transfer operation of tube transfer unit  50  is started, grippers  541 ,  542  of tube transfer unit  50  are moved to a target holding position (S 201 ), and the gripping operation is executed on the holding positions (S 202 ). At this time, as described above, it is detected that the sample tube is in the holding position. When the sample tube is in the holding position (S 203 : YES), grippers  541 ,  542  of tube transfer unit  50  execute the transfer operation on the sample tube (S 204 ). On the other hand, when the sample tube is not in the holding positions (S 204 : NO), the transfer operation is not performed. 
         [0077]    In this manner, the processes of S 201  to S 205  are repeatedly carried out until the processing is terminated on all the samples in the rack (S 205 ). When the processing is terminated on all the samples in the rack (S 205 : YES), grippers  541 ,  542  of tube transfer unit  50  are returned to the initial position (S 206 ), and the transfer processing is terminated. 
         [0078]    Return to  FIGS. 6A and 6B . The sample tube taken out from the rack is transferred by tube transfer unit  50  to position P 1  illustrated in  FIG. 2 , and the sample tube is turned down by stirrer mechanism  60  in position P 1 . Specifically, when shaft  62  is rotated by motor  61 , the front end of abutting member  63  moves along with an arch using shaft  62  as the center thereof in the X-Z plane. Accordingly, body portion Ta of the sample tube pushed by abutting member  63  from the X-axis negative side. When the sample tube is returned to the vertical state, shaft  62  is reversely rotated by motor  61  and abutting member  63  is separated from the sample tube. Accordingly, grippers  541 ,  542  gripping the sample tube are returned to the vertical state with the weight thereof. 
         [0079]    Here, abutting member  63  pushes the sample tube from the X-axis negative side, and thus tube transfer unit  50  has to position the sample tube on the X-axis positive side of abutting member  63 . Also, in the stirring processing, since the sample tube is turned down in the X-direction, space extending in the X-axis direction is needed. For this reason, in the embodiment, stirrer mechanism  60  and position P 1  are provided on the rear-left of the racks set in two drawers  30  when two drawers  30  are closed. 
         [0080]    Return to  FIG. 2 . When stirring processing by stirrer mechanism  60  is terminated in position P 1 , this sample tube is set by tube transfer unit  50  in tube set unit  71  of back-and-forth conveyance unit  70  positioned in position P 2 . Back-and-forth conveyance unit  70  includes tube set unit  71  which is capable of holding the sample tube and motor  72  to move tube set unit  71  in the back and forth directions. 
         [0081]    The sample tube set in tube set unit  71  in position P 2  is conveyed to position P 3  by tube set unit  71 . When the sample tube is positioned in position P 3 , barcode reader  82  provided near position P 3  reads sample ID from barcode label Tc adhered to the sample tube. Then, the sample tube is conveyed to position P 4  by tube set unit  71 . When the sample tube is positioned in position P 4 , a predetermined amount of sample is aspirated by sample aspiration unit  210  from the sample tube via piercer  211 . Sample aspiration unit  210  includes piercer  211  to aspiration the sample in the sample tube and motor  212  with a stepping motor to drive piercer  211  in the up and down directions. 
         [0082]    When aspiration of the sample is terminated, this sample tube is conveyed to the front of tube set unit  71  and is positioned in position P 2 . Then, this sample tube is returned to the original rack holding position by tube transfer unit  50 . In this manner, the sample tubes held in the rack are sequentially taken out and sample aspiration unit  210  aspirations the sample. 
         [0083]    The sample aspirated through piercer  211  is discharged to sample preparation unit  220 . Sample preparation unit  220  mixes the sample with a reagent and the mixed solution is heated to prepare a measurement sample. The prepared measurement sample is supplied to detector  230 . Detector  230  acquires various kinds of signals by emitting laser beams to the measurement sample. The acquired measurement result is analyzed by CPU  201  (see,  FIG. 9 ) and the analysis result is displayed in display input unit  3 . 
         [0084]    When the analysis of one sample is preferentially performed (in the case of the manual processing), the operator stirs the sample in the sample tube in advance. The operator opens door  23  and sets this sample tube in tube set unit  71  positioned in position P 5  (see,  FIG. 2 ), and then pushes start button  83 . This sample tube is conveyed to the back of tube set unit  71 . Then, barcode reader  82  reads sample ID, and the sample is aspirated. After that, this sample tube is positioned by tube set unit  71  in position P 5 , and the operator opens door  23  to take out the sample tube from case  2   a.    
         [0085]    It is to be noted that tube set unit  71  is positioned in position P 5  when processing on the two racks is not performed, and is positioned in position P 2  when processing on any one of the two racks is performed. Accordingly, the manual processing can be executed when processing is not performed on both two racks. When the manual processing is performed when processing on any one of the two racks is performed, the operator opens door  23  and sets the sample tube holding a priority sample in tube set unit  71  positioned in position P 5  after an operation of suspending the processing on the rack is performed, and presses start button  83 . 
         [0086]    Here, since piercer  211  is consumables and has to be regularly replaced by a serviceman. The serviceman replaces piercer  211  from the right surface of main body  2  in replacement. Also, tube set unit  71  moves between position P 5  where the sample tube is directly set by the operator and position P 4  where aspiration is performed by piercer  211  in the back and forth directions. For this reason, in the embodiment, tube set unit  71  is provided on the right end in main body  2  for the sake of convenience of the operator and serviceman. Also, position P 2  where the sample tube is set by tube transfer unit  50  is provided in the right direction of position P 1  so that a distance from position P 1  becomes the shortest and on the rear right side of the rack set in two drawers  30  when two drawers  30  are closed. 
         [0087]      FIG. 8A  is a diagram illustrating stirring processing by stirrer mechanism  60 .  FIGS. 8B to 8D  are diagram, each illustrating the aspiration processing by sample aspiration unit  210 .  FIG. 8E  is a conceptual diagram illustrating a setting table configuration stored in hard disk  270  (see,  FIG. 9 ) in main body  2 . 
         [0088]    Refer to  FIG. 8A . When a turned-down operation in which a sample tube is returned from the vertical state to the vertical state after the turned-down state is counted as one, the numbers of turning down the sample tubes T 1  to T 3  are respectively set to fn 1 , fn 1 , and fn 2  as indicated in the setting table in  FIG. 8E . Here, fn 1 &lt;fn 2 . Accordingly, the sample in sample tube T 3  whose capacity is smaller than those of sample tubes T 1  and T 2  can be sufficiently stirred. 
         [0089]    Now refer to  FIGS. 8B to 8D . In order to lower piercer  211  to the sample tube, the lower end of piercer  211  is aligned with the initial position, and then motor  212  is given a predetermined number of pulses and accordingly lowers piercer  211 . In this process, the number of pulses given to motor  212  is set to pn 1 , pn 2 , and pn 3  for sample tubes T 1  to T 3 , respectively, as indicated in the setting table in  FIG. 8E  so that a lowering amount becomes suitable. Here, pn 1 &gt;pn 2 &gt;pn 3 . Accordingly, piercer  211  can be properly lowered according to the height of bottom surfaces Td of sample tubes T 1  to T 3 . 
         [0090]      FIG. 9  is a block diagram illustrating the configuration of sample analyzer  1 . 
         [0091]    Main body  2  includes substrate  200 , mechanism unit  240 , sensor unit  250 , lamp unit  260 , hard disk  270 , and read device  280  in addition to above-described tube transfer unit  50 , barcode reader  82 , sample aspiration unit  210 , sample preparation unit  220 , and detector  230 . Substrate  200  includes CPU  201 , memory  202 , and interface  203 . 
         [0092]    CPU  201  executes computer programs stored in memory  202 , computer programs loaded in memory  202 , and processing illustrated in  FIGS. 7A and 7B . CPU  201  controls the units of main body  2  and display input unit  3  and receives signals from the units of main body  2  and display input unit  3 , through interface  203 . 
         [0093]    Mechanism unit  240  includes a mechanism to drive the units of main body  2 . Sensor unit  250  includes a sensor to detect that door  23  is closed and a sensor to detect that power button  11 , start buttons  12 ,  83 , or stop button  13  is pressed, in addition to above-described two sensors  41 ,  81  and  341  to  343 ,  535 . Lamp unit  260  includes two lamps  22 . 
         [0094]    Hard disk  270  stores an operating system, computer programs which are executed by CPU  201 , the configuration of projection portions Re of racks R 1  to R 6 , and the setting table in  FIG. 8E . Read device  280  includes a CD drive, DVD drive, or the like, and can read out computer programs and data, which are stored in the recording medium. 
         [0095]      FIG. 10A  is a schematic diagram illustrating the case where a portion near two drawers  30  is seen from above. 
         [0096]    In the embodiment, as described above, positions P 1  and P 2  are respectively provided in the rear left side and the rear right side of the racks set in two drawers  30 . Also, the units of main body  2  are configured so that space S 1  is provided to the rear of the rack set in the right drawer  30  and space S 2  is provided to the rear of the rack set in the left drawer  30 . Also, center portion Rb provided in the rack (see,  FIG. 3A ) forms space S 3  between the row of holding positions n 1  to n 5  and the row of holding positions n 6  to n 10 . The width of center portion Rb in the back and forth directions is set slightly larger than the diameter of body portion Ta of the sample tube. Also, space S 4  is formed between the racks set in right and left drawers  30 . Spaces S 1 , S 2 , and S 4  are spaces extending above drawers  30  in areas illustrated by the broken lines in the plan view of  FIG. 10A , and are configured to be small to an extent that tube transfer unit  50  can just transfer the sample tube. Space S 3  is a space extending above center portion Rb in the area illustrated by the broken line in the plan view of  FIG. 10A . 
         [0097]    It is to be noted that right drawer  30  and left drawer  30  respectively correspond to a “first drawer” and a “second drawer” described in claims. 
         [0098]      FIGS. 11A and 11B  are diagrams, each illustrating a path in which the sample tube held in holding position n 1  in the right rack is transferred by tube transfer unit  50 . 
         [0099]    Refer to  FIG. 11A . When the sample tube held in position n 1  in the right rack is picked out of the rack by being gripped by grippers  541 ,  542 , the sample tube is transferred slightly backwardly to be positioned in space S 3 . Subsequently, the sample tube is transferred to the left in space S 3  to be positioned in space S 4 , and is backwardly transferred in space S 4  to be positioned in a position covering spaces S 1 , S 2 . After that, this sample tube is transferred to the left in space S 2  to be positioned in position P 1 . Stirring processing is performed in position P 1  and then the sample tube is transferred to the right in space S 2  and space S 1  to be set in tube set unit  71  positioned in position P 2 . 
         [0100]    Refer to  FIG. 11B . When the sample tube positioned in position P 2  after being conveyed from the rear side by tube set unit  71  is picked out of tube set unit  71  by being gripped by grippers  541 ,  542 , the sample tube is returned to original holding position n 1  after passing the right space of the right rack and space S 3 . Similarly, the sample tubes held in holding positions n 2  to n 5  of the right rack are also transferred as illustrated in  FIGS. 11A and 11B . 
         [0101]    The sample tubes held in the rear row (holding positions n 6  to n 10 ) of the right rack are transferred to the right and left in spaces S 1 , S 2  as illustrated in  FIGS. 11C and 11D . 
         [0102]      FIGS. 12A and 12B  are diagrams, each illustrating a path in which the sample tube held in holding position n 1  of the left rack is transferred by tube transfer unit  50 . 
         [0103]    Refer to  FIG. 12A . When the sample tube held in position n 1  in the left rack is picked out of the rack by being gripped by grippers  541 ,  542 , the sample tube is firstly transferred slightly backwardly to be positioned in space S 3  and then is transferred to the left in space S 3  to be positioned in the left side of the space of the rack. After that, this sample tube is positioned in position P 1  after passing the left side of the left rack. Stirring processing is performed in position P 1  and then the sample tube is transferred to the right in space S 2  and space S 1  to be set in tube set unit  71  positioned in position P 2 . 
         [0104]    Refer to  FIG. 12B . When the sample tube positioned in position P 2  after being conveyed from the rear side by tube set unit  71  is picked out of tube set unit  71  by being gripped by grippers  541 ,  542 , the sample tube is transferred to the left in space S 1  to be positioned in space S 4 . Then, this sample tube is transferred to the left in space S 3  to be returned to original holding position n 1 . Similarly, the sample tubes held in holding positions n 2  to n 5  of the left rack are also transferred as illustrated in  FIGS. 12A and 12B . 
         [0105]    It is to be noted that the sample tubes held in the rear row (holding positions n 6  to n 10 ) of the left rack are transferred to the right and left in spaces S 1 , S 2  as illustrated in  FIGS. 12C and 12D . 
         [0106]      FIGS. 10B and 10C  are diagrams, each illustrating a case where a path in which the sample tubes held in the front row (holding positions n 1  to n 5 ) or rear row (holding positions n 6  to n 10 ) of the rack are transferred by tube transfer unit  50  is seen from the X-axis negative direction. It is to be noted that the thick arrows indicate a path of the lower end of the sample tube. 
         [0107]    Refer to  FIG. 10B . The sample tube held in the front row is picked out so that the lower end thereof is positioned slightly higher than the upper surface of the rack. Subsequently, this sample tube is slightly transferred in the Y-axis positive direction, and is transferred in the X-axis direction after passing space S 3  (see,  FIG. 10A ) between the front row and the rear row, and then is transferred to the rear side after passing space S 4  or the left space of the rack. Refer to  FIG. 10C . Similarly, the sample tube held in the rear row is picked out so that the lower end thereof is positioned slightly higher than the upper surface of the rack. Subsequently, this sample tube is transferred slightly in the Y-axis positive direction. In this manner, the sample tube is transferred through a position at which the lower end of the sample tube is slightly above the upper surface of the rack, that is, at a height level at which the lower end of the sample tube travels near the upper surface of the rack, and the sample tube is not lifted to a level much higher than that. In other words, the transfer path set as described above enables the sample tube to be smoothly carried without lifting the sample tube largely. 
         [0108]    Also, in the embodiment, when a rack is not set in drawer  30 , lamp  22  above this drawer  30  is lit in green, and the lock of this drawer  30  is released. In addition, when a rack is set in drawer  30  but processing on the rack is not started yet, lamp  22  above this drawer  30  is also lit in green and the lock of this drawer  30  is released. Also, when processing on the rack set in drawer  30  is started and transferring the sample tube in the rack is started, lamp  22  above this drawer  30  flashes in green and this drawer  30  is locked. Also, when the processing on all the racks set in drawer  30  is terminated, lamp  22  above drawer  30  is lit off and the lock of drawer  30  is released. 
         [0109]    It is to be noted that as illustrated in  FIG. 7C , lighting processing of lamp  22  is controlled by CPU  201 . This lighting processing is performed so that lamp  22  becomes the state illustrated on the right row in  FIG. 2C  when the state of drawer  30  is in the state illustrated in the left row in  FIG. 7C . 
         [0110]    As described above, in the embodiment, corresponding drawer  30  is forwardly pulled and the rack can be set in this drawer  30  when lamp  22  is lit in green and is lit off, and is not forwardly pulled and this drawer  30  cannot be set when lamp  22  flashes in green. Accordingly, it can be seen that an operator can see whether or not a rack can be set in corresponding drawer  30  by checking the state of lamp  22 . 
         [0111]    As described above, in the embodiment, as illustrated in  FIGS. 12A and 12D , the sample tube held in the left rack is transferred passing space S 1  on the rear side of the right rack without passing the front side of the right rack when the sample tube is positioned in position P 2 . Accordingly, even when the sample tube is being transferred from the left rack to position P 2 , the right rack can be forwardly pulled from main body  2 . Thus, the sample tube can be efficiently replaced. 
         [0112]    Also, the sample tube which is transferred from the left rack to position P 2  is positioned in a place where the lower end thereof is slightly higher than the upper surface of the rack. In other words, the sample tube is transferred in a height in which the lower end thereof comes near the upper surface of the rack and is not lifted higher than this. For this reason, the sample tube being transferred from the left rack does not have to be lifted to a level higher than the upper end of the sample tube held in the right rack in order to avoid contact with the sample tube of the right rack when the right rack is pulled out. This can avoid increasing the size of the outer shape of sample analyzer  1  in the height direction. 
         [0113]    As described above, sample tubes T 1  to T 3  used in the embodiment are used as blood-collecting tubes, for example. As illustrated in  FIGS. 3C to 3E , they have an elongate shape. For this reason, when a sample tube is picked out of a rack and transferred, the lower portion of the sample tube to be transferred may cause interference on the upper portion of other sample tubes. This problem can be solved by largely lifting the sample tube so that the lower portion of the sample tube to be transferred becomes higher than the upper portion of other sample tubes. However, in this case, a large stroke to lift a sample tube needs to be provided inside sample analyzer  1 , which causes an increase in the size of sample analyzer  1  in the height direction. For this reason, to solve the above problem and to suppress the increase in the size of sample analyzer  1  in the height direction, the transfer path of the sample tube has to be devised. In the embodiment, the transfer path of the sample tube set as described above enables avoidance of increase in the outer shape of sample analyzer  1  in the height direction, and smooth transfer of the sample tube. 
         [0114]    Also, in the embodiment, as illustrated in  FIGS. 11A to 11D , the sample tube held in the right rack is transferred passing space S 2  on the rear side of the left rack without passing the front side of the left rack when the sample tube is positioned in position P 1  where is a stirring position by stirrer mechanism  60 . Accordingly, even when the sample tube is being transferred from the right rack to position P 1 , the left rack can be forwardly pulled from main body  2 . Thus, the sample tube can be efficiently replaced. Also, since there is no need to lift the sample tube to a level higher than the upper end of the sample tube held by the left rack when the sample tube is being transferred from the right rack to position P 1 , the increase in the outer shape of sample analyzer  1  in the height direction can be avoided. 
         [0115]    Also, in the embodiment, right and left drawers  30  include rack set unit  300 , and a rack is detachably attachable to rack set unit  300 . Accordingly, the sample tubes can be replaced all together at once, and thus the sample tube can be further efficiently replaced. 
         [0116]    Also, in the embodiment, the rack has the configuration in which five holding portions Ra are arranged in two rows, so that the shape of the rack can be compact in the plan view. As a result, the shape of sample analyzer  1  can be compact. Also, center portion Rb is formed between the row of holding portions Ra in holding positions n 1  to n 5  and the row of holding portions Ra in holding positions n 6  to n 10 , and space S 3  formed by center portion Rb is used as a transfer space for the sample tubes. Accordingly, the transfer operation can be smoothly achieved. 
         [0117]    Also, in the embodiment, space S 4  formed between the racks set in the left and right drawers  30  is used as a transfer space for the sample tubes. Accordingly, the transfer operation can be smoothly achieved. 
         [0118]    Also, in the embodiment, when the processing on the rack set in drawer  30  is started and transferring the sample tube in the rack is started, drawer  30  is locked. Accordingly, it can be prevented that the rack in which transferring the sample tube is started is wrongly pulled out to block the transfer of the sample tube by tube transfer unit  50 . 
         [0119]    Also, in the embodiment, it is detected whether or not a sample tube is in a holding position when a gripping operation is performed by grippers  541 ,  542  in the holding position. When the sample tube is not held, the transfer operation for the sample tube to this holding position is suspended. Accordingly, the unnecessary transfer operation by tube transfer unit  50  can be avoided and the transfer of the sample tube can be effectively continued. 
         [0120]    Also, in the embodiment, corresponding drawer  30  can be forwardly pulled out and the rack can be set in this drawer  30  when lamp  22  is lit in green and when lamp  22  is lit off. When lamp  22  flashes in green, drawer  30  cannot be forwardly pulled out and the rack cannot be set in this drawer  30 . Accordingly, an operator can intuitively see whether or not corresponding drawer  30  can be set in the rack by checking the state of lamp  22 . Thus, the sample tube may be smoothly replaced. 
         [0121]    As described above, the embodiment is described. However, the invention is not limited to the embodiment, and various modifications are possible in addition to the embodiment of the invention. 
         [0122]    For example, in the above embodiment, a device to which the invention is applied is assumed to be sample analyzer  1  to analyze blood. However, it is not limited to this. The invention may be applied to a sample processing apparatus to perform processing on a sample, such as an immunity analyzer, gene amplification measurement device, biochemical analyzer, urine qualitative analyzer, in-urine physical component analyzer, or blood smear creation device. 
         [0123]    Also, a transfer path of a sample tube is not limited to those described in the above-described embodiment and may be modified as appropriately. 
         [0124]    For example, in the embodiment, the sample tube taken out from the front row of the rack is transferred to the left in space S 3  after being slightly transferred backwardly. However, the embodiment is not limited to this. As illustrated in  FIGS. 13A and 13C , the taken-out sample tube may be conveyed to the left in a space on the front of the rack after being slightly forwardly transferred. It is to be noted in this case that the sample tube to be returned from position P 2  to the original holding position of the rack is transferred as illustrated in  FIGS. 13B and 13D . 
         [0125]    In this manner, after the sample tube is transferred, space S 3  is no longer used for transfer. Accordingly, it is no longer necessary to provide the gap between the front and rear rows of the rack as described in the embodiment. Thus, as illustrated in  FIGS. 13A to 13D , the width of the rack in the back and forth direction can be reduced, so that miniaturization of the rack can be achieved. However, when the rack is configured with a small gap between the front and rear rows, the rack easily tends to tilt in the back and forth directions. Accordingly, in order for the rack to stably stand up for itself, it is preferable to provide space S 3  as described in the embodiment. Also, in the cases of  FIGS. 13A to 13D , since the sample tube travels in front of the rack, the transfer distance is longer than that in the embodiment. For this reason, to shorten the transfer time, it is preferable to provide space S 3  and use space S 3  as a conveyance path as described in the embodiment. 
         [0126]    In addition, in the embodiment, the sample tube taken out from the front row of the right rack is transferred to the left in space S 3  and is backwardly transferred in space S 4 . Also, the sample tube to be returned from position P 2  to the front row of the left rack is forwardly transferred in space S 4  and is transferred to the left in space S 3 . However, the embodiment is not limited to this. As illustrated in  FIG. 14A , the sample tube taken out from the front row of the right rack may be transferred to the right in space S 3  and be backwardly transferred in the space on the right side of the right rack. Also, as illustrated in  FIG. 14D , the sample tube to be returned to the front row of the left rack from position P 2  may be forwardly transferred in the space on the left side of the left rack and be transferred to the right in space S 3 . It is to be noted that in this case that, as similar to the embodiment, the sample tube to be returned to the front row of the right rack from position P 2  and the sample tube taken out from the front row of the left rack are respectively transferred as illustrated in  FIGS. 14B and 14C . 
         [0127]    In this manner, after the sample tube is transferred, space S 4  is no longer used for transfer. Accordingly, it is no longer necessary to provide the gap between the right and left racks as described in the embodiment. Thus, as illustrated in  FIGS. 14A to 14D , the gap between the right and left racks can be reduced, so that miniaturization of sample analyzer  1  can be achieved. However, in this transfer path, since the sample tube travels around the right side of the right rack as illustrated in  FIG. 14A  and the sample tube travels around the left side of the left rack as illustrated in  FIG. 14D , the transfer distance is longer than that in the embodiment. For this reason, to shorten the transfer time, it is preferable to provide space S 4  and use space S 4  as a conveyance path as described in the embodiment. 
         [0128]    In addition, in the embodiment, the sample tube to be returned to the front row of the right rack from position P 2  is forwardly transferred in the space on the right side of the right rack and is transferred to the left in space S 3 . Also, the sample tube taken out from the front row of the left rack is transferred to the left in space S 3  and is backwardly transferred in the space on the left side of the left rack. However, the embodiment is not limited to this. As illustrated in  FIG. 15B , the sample tube to be returned from position P 2  to the front row of the right rack may be forwardly transferred in space S 4  and be transferred to the right in space S 3 . Also, as illustrated in  FIG. 15C , the sample tube taken out from the front row of the left rack may be transferred to the right in space S 3  and be backwardly transferred in space S 4 . It is to be noted in this case that, as similar to the embodiment, the sample tube taken out from the front row of the right rack and the sample tube to be returned to the front row of the left rack from position P 2  are respectively transferred as illustrated in  FIGS. 15A and 15D . 
         [0129]    As described above, after the sample tube is transferred, the space on the right side of the right rack and the space on the left side of the left rack are no longer used for transfer. Accordingly, mechanism inside sample analyzer  1  can be provided therein, so that miniaturization of sample analyzer  1  can be achieved. However, in this transfer path, since the sample tube travels around the left side of the right rack as illustrated in  FIG. 15B  and the sample tube travels around the right side of the left rack as illustrated in  FIG. 15C , the transfer distance is longer than that in the embodiment. For this reason, to shorten the transfer time, it is preferable that the space on the right side of the right rack and the space on the left side of the left rack be used for the conveyance path. 
         [0130]    Also, in the embodiment, the sample tubes taken out from the rear row of the right and left racks are transferred as illustrated in  FIGS. 11C and 12C , and the sample tubes to be returned to the rear row of the right and left racks from position P 2  are transferred as illustrated in  FIG. 11D  and  FIG. 12D . However, the embodiment is not limited to this. The sample tubes taken out from the rear row of the right and left racks may be transferred passing space S 3  after being slightly forwardly transferred. Also, the sample tubes to be returned from position P 2  to the rear row of the right and left racks may be returned to the original holding position after being transferred passing space S 3 . However, even in the case of these paths, the transfer distance of the sample tube is longer than that in the embodiment. Thus, to shorten the transfer time, it is preferable that the transmission path in the embodiment be used. 
         [0131]    Also, in the embodiment, two drawers  30  capable of being drawn out from the front side of main body  2  are arranged side by side. The embodiment is not limited to this. Three or more drawers  30  may be arranged side by side. In this case, positions P 1  and P 2  are respectively provided on the rear left and rear right sides of drawers  30  arranged side by side, and sample tubes are transferred in a path passing behind other rack. 
         [0132]    Also, in the embodiment, the stirring processing on the sample tube is performed in position P 1 , but the embodiment is not limited to this. Other processing may be performed in position P 1 . For example, when the sample tube is stirred in the conveyance path by back-forth conveyance unit  70 , barcode label Tc of the sample tube may be read in position P 1 . 
         [0133]    Also, in the embodiment, the rack is configured to be detachably attached to drawer  30 . However, the rack does not necessarily have to be configured to be detachably attached to drawer  30 . In the embodiment, the kind of the sample tube is identified by the shape of the rack. However, for example, when kinds of sample tubes are manually inputted, the attachable/detachable rack does not have to be used and the rack may be integrated with drawer  30 . However, even in a case where kinds of sample tubes are manually inputted, it is better to use the attachable/detachable rack because the sample tubes can be replaced all together at once and thus workability and convenience can be improved. 
         [0134]    Also, in the embodiment, the rack has the configuration in which five holders Ra are arranged in two rows. However, the embodiment is not limited to this. Holders Ra may be provided in three or more rows in the rack or holders Ra may be provided in one row in the rack. 
         [0135]    Also, in the embodiment, the rack is set in drawer  30  so that five holders Ra arranged in left and right directions in the two rows in the back and forth directions. However, the embodiment is not limited to this. The rack may be set in drawer  30  so that five holders Ra arranged in the back and forth directions are arranged in two rows in the right and left directions (pulled out direction of drawer  30 ). In other words, the moving direction of drawer  30  and the rows of holders Ra may be in parallel. In this case, rack set unit  300  of drawer  30  is configured to be rotated by 90 degrees in the X-Y plane and grippers  541 ,  542  are configured to be rotated by 90 degrees in the X-Y plane. 
         [0136]    Also, in the embodiment, the width of center portion Rb of the rack in the back and forth directions is set so to be slightly larger than the diameter of body portion Ta of the sample tube. However, the embodiment is not limited to this. It is only needed that the sample tube to be transferred by tube transfer unit  50  can be transferred in the right and left directions in space S 3  formed by center portion Rb. However, when the width of center portion Rb in the back and forth directions is set larger, the size of the rack is also increased. Thus, it is preferable that center portion Rb be configured as small as possible as described in the embodiment. 
         [0137]    Also, in the embodiment, spaces S 1 , S 2 , and S 4  are formed as small as an extent that tube transfer unit  50  is capable of transferring the sample tube. However, the embodiment is not limited to this. Spaces S 1 , S 2 , and S 4  may be formed to be larger than that in the embodiment. However, when the sizes of spaces S 1 , S 2 , and S 4  are increased, the size of sample analyzer  1  is also increased. Thus, it is preferable that spaces S 1 , S 2 , and S 4  be formed as small as possible as described in the embodiment. 
         [0138]    Also, in the embodiment, when the transfer operation for the sample tube is started with respect to the rack set in drawer  30 , this drawer  30  is locked. However, the embodiment is not limited to this. Drawer  30  may be locked at a predetermined timing after the transfer operation of the sample tube is started. For example, after the transfer operation of the sample tube with respect to the rack is started and before grippers  541 ,  542  reach an area above the rack, drawer  30  may be locked. It is preferable that drawer  30  be locked at least during a period of time in which grippers  541 ,  542  or the sample tube gripped by grippers  541 ,  542  and the sample tube held in the rack interfere with each other when drawer  30  is pulled out. 
         [0139]    Also, in the above-described embodiment, the state of drawer  30  is displayed by display of lamp  22 . However, it may be always displayed by display input unit  3 . 
         [0140]    Also, in the embodiment, spaces S 1 , S 2  through which the sample tube passes are provided above two drawers  30 . However, the way to provide spaces S 1 , S 2  is not limited to this. For example, spaces S 1 , S 2  may be provided to the rear of the back sides of drawers  30  in the state where two drawers  30  are closed. 
         [0141]    In this way the embodiments described above provide a sample analyzer and a rack that enable sample tube replacement in a sample tube set unit even during measurement.