JPH0763772A - Dispensing device - Google Patents

Abstract

PURPOSE:To accurately control the discharging amount of a nozzle at the dispensing time of a dispensing device by providing a control means which makes the nozzle to again discharge part of a suckedin liquid into a single container after the nozzle sucks in the liquid. CONSTITUTION:Firstly, a nozzle tip 13 is put in a liquid by lowering the tip 13 by a prescribed amount. Then the liquid is sucked into the tip 13 and, at the same time, the tip 13 itself is lowered in order to cope with the drop of the liquid level. Then, after having a fixed quiescent time, the liquid is discharged by a prescribed amount (returning control) while the front end of the tip 13 is kept in the liquid. Because of the returning control, the detecting value of the pressure at a dispensing nozzle 25 becomes the same as that when the first discharge is performed. Thereafter, the tip 13 is raised by a prescribed amount after having a fixed quiescent time. Since the front end of the tip 13 is exposed to the air when the tip 13 is raised, an air gap is formed to cope with the first transportation. Therefore, all discharging amounts can be controlled within a tolerance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispensing device for dispensing a specific liquid into a plurality of test containers in precise amounts.

[0002]

2. Description of the Related Art Various reagents, samples, or liquids to be sampled such as blood are dispensed into a plurality of test tubes, microplates, or other test containers in predetermined amounts, and when testing or measuring a plurality of items, Note equipment is used.

In this sampling and dispensing apparatus, a sampling side having a supply container storing each of the above-described sampling target liquids and an assay side having a plurality of test containers into which the sampling target liquids are distributed are arranged in an adjacent state,
With the dispensing nozzle attached to the dispensing head that reciprocates between these supply container and test container, the liquid to be sampled is sucked from the supply container on the sampling side, and a predetermined amount of this liquid is put into the test container on the assay side. They are distributed one by one.

In the conventional sampling and dispensing apparatus, a syringe pump is fixedly mounted on a dispensing nozzle attached to a dispensing head that moves back and forth, left and right, and up and down, and these are connected by a flexible pipe. It is generally of a structured structure. In other words, when sucking the liquid to be sampled into the dispensing nozzle, if the plunger of the syringe pump is driven so as to be pulled out from the pump chamber, the liquid to be sampled will be dispensed via the pipe in an amount corresponding to the volume change in the pump chamber. Inhaled into the injection nozzle. Conversely, when the plunger of the syringe pump is driven so as to be pushed toward the pump chamber side, the sampling target liquid in the dispensing nozzle is discharged to the test container side through the pipe in an amount corresponding to the volume change in the pump chamber.

Further, when the liquid to be sampled is sucked from the supply container side to the dispensing nozzle side using the conventional dispensing device, the lower end of the nozzle tip at the tip of the dispensing nozzle separates from the surface of the liquid to be sampled and sucks air. If you get
Dispensing operation cannot be performed accurately. For this reason,
Conventionally, a pressure sensor or the like is used for the pressure in the dispensing nozzle, and it is determined whether or not there is an abnormality in the detected value, and the sampling operation is stopped when the abnormality occurs.

Further, in order to carry out various kinds of tests and measurements on a liquid to be sampled such as blood which is desired to be suppressed from the subject as much as possible, the dispensing amount is inevitably small. It is necessary to set it, and the accuracy of this dispensing amount influences the reliability and accuracy of the inspection results and measurement results.

However, in the case of the conventional sampling and dispensing apparatus in which the syringe pump is installed in a fixed state, the bending state of the pipe interposed between the syringe pump and the dispensing nozzle is subtle along with the movement of the dispensing nozzle. Therefore, there is a problem that the error of the dispensing amount increases especially in the case of dispensing a small amount due to the influence of the volume fluctuation in the pipe.

In order to solve such a problem, the inventors of the present invention have incorporated a syringe pump in the dispensing head to which the dispensing nozzle is attached according to Japanese Utility Model Laid-Open No. 5-23105, etc., and the dispensing nozzle and the syringe pump. We have already proposed a sampling and dispensing device in which and are connected via a passage that does not deform.

As described above, in the case of performing various kinds of inspections and measurements using a very small amount of the sample liquid, the pipe formed between the dispensing nozzle and the syringe pump is affected by the temperature and atmospheric pressure fluctuations. It is advisable to make the passages and walkways as short as possible or even to eliminate them. In addition, when the dispensing nozzle and the syringe pump are brought close to each other as in Japanese Utility Model Laid-Open No. 5-23105, a part of the liquid to be sampled flows into the syringe pump, and the liquid to be sampled easily coagulates like blood. In this case, there is a risk that the piping connected to the pressure sensor will be clogged, and the ease of maintenance of these is also required. In this respect, the sampling and dispensing device proposed in Japanese Utility Model Laid-Open No. 5-23105, etc., still has room for improvement.

On the other hand, when sucking the liquid to be sampled in the supply container into the dispensing nozzle with the conventional sampling and dispensing apparatus, it is necessary to experimentally confirm the correlation between the detected value from the pressure sensor and the actual presence or absence of abnormality. Therefore, every time the specification of the device, the capacity of the syringe pump, or the like changes, the correlation between the detection value from the pressure sensor and the actual presence or absence of abnormality must be reconfirmed experimentally, which is very troublesome.

Moreover, since the change in pressure inside the dispensing nozzle is not continuously monitored, there is a risk that it is not possible to detect an abnormality associated with the temporary inhalation of bubbles, foreign substances, etc. contained in the liquid to be sampled. If the dispensing work is performed as it is, there is a risk that the subsequent inspection results, measurement results, etc. may be adversely affected.

[0012]

In view of the current state of the prior art as described above, the applicant of the present application filed an invention for the following purposes as of May 19, 1993.

By completely eliminating the pipes and passages that connect the dispensing nozzle and the syringe pump, and reducing the dispensing error due to temperature and atmospheric pressure fluctuations as compared with the conventional one, it is possible to use a very small amount of the sample liquid. (EN) Provided is a dispensing device which can improve the reliability of various kinds of inspections and measurements, and which is extremely easy to maintain.

An inhalation abnormality detection method capable of easily and reliably detecting an abnormality during inhalation of a liquid to be sampled.

In the dispensing device of the above application by the applicant,
The dispensing nozzle itself has a pump chamber that is a part of the syringe pump, and has no pipe or passage connecting the syringe pump and the dispensing nozzle.

When the plunger raising / lowering drive means raises the plunger, the liquid to be sampled is sucked into the nozzle tip as the volume of the pump chamber increases corresponding to the rise, and conversely, the plunger raising / lowering drive means By lowering, the liquid to be sampled is discharged from the nozzle tip to the outside as the volume in the pump chamber corresponding to this lowering decreases.

Further, in the above-mentioned application, the pressure in the nozzle tip is read as a reference pressure after a predetermined time has passed after the suction of a predetermined amount of the liquid to be sampled into the nozzle tip, and the sampling target sucked in the nozzle tip is read. The first upper limit value of the pressure in the nozzle tip according to the suction amount of the liquid is set based on this reference pressure. Then, the first upper limit value is compared with a preset second upper limit value and the larger value is adopted as the final upper limit value, and the sampling target liquid is inhaled after the first upper limit value is set. When the pressure inside the nozzle tip in the inside is larger than the final upper limit value, the method of judging that the suction is abnormal is adopted.

However, also in the invention according to the above-mentioned application, in the case where the liquid is collectively sucked into a dispensing nozzle tip from a certain single container and a small amount is continuously dispensed to a plurality of containers. In the case of performing so-called 1: N dispensing, it is difficult to keep all dispensed amounts within a desired error at all times.

That is, since the liquid to be dispensed does not have uniform specific gravity and viscosity, the first dispensed amount (that is, the first liquid amount discharged from the nozzle tip) and the second and subsequent dispensed amounts. The fact is that they are not always the same.

Therefore, an object of the present invention is to accurately inject the discharge amount at all dispensing when liquid is collectively inhaled from a single container and dispensed continuously to a plurality of containers. The purpose of the present invention is to provide a dispensing device configured to be controlled.

[0021]

In order to achieve such an object, the present invention uses a dispensing nozzle tip which can be moved back and forth, left and right, and up and down respectively to perform suction from a single liquid container, Is a dispensing device that discharges a prescribed amount into a container, and after inhaling a predetermined amount by the dispensing nozzle tip, a part of the inhaled liquid is again replenished from the dispensing nozzle tip to the single liquid. It is provided with a control means for discharging into the container.

Here, in addition, a pump chamber formed in the upper part of the dispensing nozzle for mounting the dispensing nozzle tip, and inside the nozzle chip formed in the lower part of the dispensing nozzle and the pump. A passage communicating with the chamber, a plunger slidably fitted in the pump chamber, a plunger lifting drive pulse motor for lifting the plunger, and a rotation direction of the pulse motor controlled according to a predetermined sequence. It is preferable to include a driving means.

[0023]

According to the above construction of the present invention, when a certain liquid is continuously dispensed into a plurality of containers, the liquid sucked into the dispensing nozzle is not dispensed immediately into the plurality of containers. Instead, the liquid sucked into the dispensing nozzle tip is discharged back into the container again, and as a result, the same state as when the first dispensing was performed occurs in the nozzle tip before the start of dispensing. It is possible to blame.

In this way, it is possible to reliably discharge the prescribed amount during all dispensing from the first time to the Nth time. In particular, even when each discharge amount is a very small amount, for example, several tens of microliters, so-called 1: N dispensing can be accurately performed, and high-speed / multi-variation which cannot be performed by the conventional dispensing device.・ A large amount of dispensing work is possible.

[0025]

Embodiments of the present invention will now be described in detail with reference to the drawings.

The appearance of an embodiment of the dispensing device according to the present invention is shown in FIG. That is, a large number of nozzle tips 13 are provided at the rear of the work table 12 in which the column 11 is erected at the rear end.
A chip rack 14 in which the used nozzle chips 13 are stored at a predetermined interval and a chip storage box 15 in which the used nozzle chips 13 can be stored are placed on the work table 12 in front of the chip rack 14 and the chip storage box 15. Is a sample rack 17 for storing a large number of supply containers 16 each storing a liquid to be sampled at a predetermined interval, and a sample rack 17
A plurality of test containers 18 into which a predetermined amount of the liquid to be sampled from each side is dispensed are mounted side by side with an assay rack 19 that stores a plurality of test containers 18 at predetermined intervals.

A pair of left and right arms 20 parallel to each other are provided on the upper portion of the column 11 so as to project forward, and a horizontal cross whose left and right ends are reciprocally held back and forth with respect to these arms 20. A saddle 22 is held on the beam 21 so as to be capable of reciprocating left and right along the cross beam 21. Further, a ram 23 is attached to the saddle 22 so as to be vertically movable along the saddle 22, and the liquid to be sampled is sucked from the inside of the supply container 16 on the side of the sample rack 17 to the assay rack 19 side. A dispensing head 24 that sorts a predetermined amount of liquid to be sampled is integrally connected to the test container 18. And
The longitudinal movement of the cross beam 21, the lateral movement of the saddle 22, and the vertical movement of the ram 23 control the operation of the cross beam drive motor, saddle drive motor, and ram drive motor (not shown) housed in the column 11. Each of them is controlled by a control device (not shown), and basically, a new nozzle tip 13 in the tip rack 14 is attached to a dispensing head 24 and the dispensing nozzle 2 is attached.
5 is attached to the lower end of the sample rack 17, and the liquid to be sampled is supplied from the predetermined supply container 16 on the sample rack 17 side to the nozzle tip
The nozzle tip 1 is inhaled into each of the plurality of test containers 18 on the side of the assay rack 19 and then dispensed.
3 is removed from the lower end of the dispensing nozzle 25 and discarded in the chip storage box 15, a new nozzle chip 13 in the chip rack 14 is mounted again on the lower end of the dispensing nozzle 25, and the above-described dispensing operation is repeated. .

Since the driving mechanism of the dispensing head 24, the control mechanism of the dispensing operation, and the like described above are well known in the art, further detailed description will be omitted.

The internal mechanism of the dispensing head 24 in this embodiment is shown in FIGS. 1 and 3 to 5, respectively. That is,
A pair of left and right guide rods 28, 29 parallel to each other are vertically slidably pierced through a head holder 27 integrally connected to the ram 23 via a head bracket 26. The upper and lower ends of the upper and lower casings 29 are integrally fitted to the pair of upper and lower casing holders 30 and 31 via the set screws 32, respectively. A central portion and a lower end portion of a casing 33 having a frame shape are screwed to the casing holders 30 and 31, respectively, and one guide rod 28 is provided between the head holder 27 and the lower casing holder 31. The fitted compression coil spring 34 is interposed.

That is, the casing 33 side is in a state of being supported by the upper end surface of the head holder 27 by the self-weight and the spring force of the compression coil spring 34, but in the present embodiment, the guide rod 29 of the other side. The tubular bush 35 and the elastically deformable cushioning ring 36 are fitted to the upper end portion, and the lower end of the bushing 35 abuts the upper end surface of the head holder 27 via the cushioning ring 36.
The position of the dispensing head 24 in the normal state with respect to No. 3 is regulated.

In this embodiment, the nozzle tip 13 is mounted on the dispensing nozzle 25 by pushing the lower end of the dispensing nozzle 25 into the upper end of the nozzle tip 13 housed in the tip rack 14. . At this time, the casing 33 side is pushed up against the head holder 27 against the spring force of the compression coil spring 34.
A pair of upper and lower magnetic sensors 37 for detecting the rising end of the head holder 27 on the casing 33 side are assembled to the lower end of the head holder 27 and the lower casing holder 31 so as to face each other, and detection signals from these magnetic sensors 37 are output. In this case, the above-described control device determines that the nozzle tip 13 is attached to the dispensing nozzle 25, and immediately stops the further lowering operation of the ram 23. At this time, in order to prevent the lower end surface of the head holder 27 and the upper end surface of the lower casing holder 31 from directly contacting each other, an elastically deformable cushioning ring 38 is fitted to the lower end portion of the other guide rod 29 in this embodiment. The lower end surface of the head holder 27 and the upper end surface of the lower casing holder 31 can come into contact with each other via the buffer ring 38.

The upper end portion of the dispensing nozzle 25, which has a fitting portion 39 for fitting the nozzle tip 13 at the lower end, is integrally fitted to one side end portion of the lower casing holder 31 via a set screw 40. Has been done. A pump chamber 41 is formed in an upper portion of the dispensing nozzle 25, and a passage 42 is formed in a lower portion of the dispensing nozzle 25 and has an upper end communicating with the pump chamber 41.
The lower end of the is open to the lower end of the fitting portion 39. Further, a plunger 44 that is tightly fitted to the pump chamber 41 is formed at a lower portion of the feed screw shaft 43 that vertically penetrates the upper casing holder 30.
A detent pin 45 having a rectangular cross section is integrally fitted to the feed screw shaft 43 via a set screw 46 at the upper end of the feed screw shaft 43. A pin bracket 48 having a pin guide hole 47 in which the rotation stop pin 45 is slidably engaged in the vertical direction is screwed to the upper casing holder 30, and a feed nut screwed to the feed screw shaft 43. 49 is rotatably held by the upper casing holder 30 via a pair of upper and lower bearings 50 while penetrating the upper casing holder 30.

As described above, in this embodiment, the dispensing nozzle 25
The upper end of the lower casing holder 31 to the set screw 4
0, which is detachably fitted to the inside of the pump chamber 41 due to clogging or the like, and the passage 4 communicating with the pump chamber 41.
2 and the inside of the connecting pipe, which will be described later, can be performed very easily by loosening the set screw 40 and removing the dispensing nozzle 25 from the lower casing holder 31.

On the other hand, on the upper casing holder 30,
A stepping motor 51 is erected downward through a plurality of columns 52, and a lower end portion thereof is a toothed drive pulley 54 integrally fitted to a motor rotating shaft 53 located in the upper head casing holder 31. An endless toothed belt 56 is wound around a toothed driven pulley 55 that is coaxially and integrally fitted to the upper end of the upper feed nut 49. Further, in order to reliably transmit the driving force from the motor rotating shaft 53 of the stepping motor 51 to the feed nut 49 side by increasing the meshing amount of the toothed belt 56 with the toothed drive pulley 54 and the toothed driven pulley 55, A tension roller 57 is rotatably mounted on the upper head casing holder 31 so as to be in rolling contact with the outer peripheral surface of the toothed belt 56.

Therefore, since the detent pin 45 integrated with the feed screw shaft 43 is slidably engaged with the pin guide hole 47, the motor rotating shaft 53 of the stepping motor 51.
By rotating the pump 44 forward and backward, the plunger 44 can be moved up and down without rotating together with the feed screw shaft 43, and the volume in the pump chamber 41 can be adjusted according to the rotation amount of the motor rotating shaft 53. .

Further, in order to define the descending end position of the plunger 44 in the pump chamber 41, the detent pin 45 is provided.
A pair of left and right optical switches 58 for detecting the descending end position of the optical switch 58 are erected at the lower end of the pin bracket 48 via a switch bracket 59, and when the detent pin 45 blocks these optical switches 58, the optical switch 58 Is turned on, and the above-mentioned control device immediately stops the operation of the stepping motor 51 in response to the ON signal of the optical switch 58, and the lower end position of the plunger 44 is regulated.

A tip portion of a connecting pipe 60 fixed to the side wall of the dispensing nozzle 25 and communicating with a lower end portion of the pump chamber 41;
A pressure sensor 61, which is attached to the lower part of one side end of the casing 33 and detects the pressure in the pump chamber 41, is connected to each other via a flexible communication pipe 62 formed of silicon resin or the like. A detection signal from the pressure sensor 61 is output to the control device described above, and the operations of the ram drive motor and the stepping motor 51 described above are controlled via the control device based on the detection signal, while the suction operation is performed. It is designed to judge abnormalities and the like.

The operation of the ram 23 and the plunger 44 and the pressure sensor 61 at the time of inhaling the liquid to be sampled.
FIG. 6 schematically shows the relationship with the detection value by.

That is, in the preparatory operation area, the dispensing head 24 is moved to the position of one of the predetermined supply containers of the predetermined sample rack 17.
6, the ram 23 is further lowered to make the lower end of the nozzle tip 13 stand by in a state of being close to the liquid surface of the liquid to be sampled in the supply container 16. From this state, the operation moves to the liquid level detection operation area, the ram 23 is lowered at a low speed, and the plunger 44 is synchronized with the lowering operation of the ram 23.
Is pulled up at a speed lower than the descending speed of the ram 23, the detected value of the pressure sensor 61 in this state is read, and the ram 23 and the feed screw shaft 43 are stopped when the detected value exceeds a preset value. Then, after a lapse of a predetermined time, the operation shifts to the suction operation region, the plunger 44 is moved at a high speed by a predetermined amount from the above-described state, and the ram 23 is synchronously lowered at a low speed corresponding to the suction ratio by the plunger 44. That is, a predetermined amount of the liquid to be sampled is sucked into the nozzle chip 13 with only the tip of the nozzle chip 13 being immersed in the liquid to be sampled. After a lapse of a certain time after the end of this suction operation, a retracting operation for raising the ram 23 is performed, and then the dispensing head 2
4 to 18 of a given test container of a given assay rack 19.
Move right above to start dispensing work.

Immediately after the start of the suction operation, the pressure sensor 6
The first peak pressure P _P which is generated in the detection value of 1, a phenomenon that the pressure of the temporary pump chamber 41 surface tension of the sampled liquid is destroyed is decreased, the peak pressure P _P is sampled It has been experimentally confirmed that it becomes almost constant depending on the type of liquid. Further, when the normal suction operation is performed, the negative pressure in the pump chamber 41 increases at a constant rate with the passage of time.

In the present embodiment, when the value detected by the pressure sensor 61 suddenly changes in this suction operation region and temporarily rises as shown by the alternate long and short dash line in FIG. It is determined that the lower end of the sample is temporarily separated from the liquid surface of the liquid to be sampled and sucks air, or that air bubbles, foreign matter, etc. in the liquid to be sampled are temporarily sucked. In this case, since there is a high possibility that the dispensing accuracy at the time of dispensing into the test container 18 cannot be ensured, it is determined that the suction operation is abnormal, and the current work is stopped. That is, the nozzle tip 13 used this time is discarded in the tip storage box 15, a new nozzle tip 13 in the tip rack 14 is attached to the lower end of the dispensing nozzle 25 again, and the suction operation of the liquid to be sampled is repeated again. .

1: N Dispensing In the present specification, a liquid contained in a single container is sucked into a dispensing nozzle (more precisely, a nozzle tip), and the liquid is dispensed to N containers. Dispensing continuously by a specified amount is called 1: N dispensing. Therefore, when inhaling the liquid in one container and dispensing it into another container,
Called dispensing.

Next, the test results when performing 1: 5 dispensing using this embodiment will be described.

FIG. 7 and FIG. 8 show the dispensing amount accuracy when 25 microliters of 1: 5 dispensing was performed using seven types of samples. In each of these figures, the horizontal axis represents the first nozzle tip ejection (1st) to the fifth nozzle tip ejection. The vertical axis represents what percentage the actual discharge amount corresponds to the target dispensing amount (25 microliters). Therefore, when 25 microliters is completely discharged, it is plotted at the position of 100%.

The seven kinds of samples used here are purified water (DW), serum (Serum) and various other reagents shown in Table 1 below.

[0046]

[Table 1]

The solid lines (98%, 102%) in the lateral direction shown in FIGS. 7 and 8 are the upper limit value and the lower limit value, respectively, and each discharge amount (dispensing amount) falls within the allowable range sandwiched between these two lines. Is included, it means that a good dispensing was performed.

However, as is clear from both FIGS. 7 and 8, depending on the sample, the first dispensing (1 s
The ejection amount in t) is outside the allowable range. This is considered to be caused by the viscosity and specific gravity of the sample and the material and shape of the nozzle tip. Therefore, in order to elucidate the causes of these, an additional 25 microliters of water 1:
Three-time dispensing was performed, and the detection values of the pressure sensor 61 (see FIG. 1) at that time were plotted.

FIG. 9 shows the detection value of the pressure sensor when performing a 1: 3 dispense using a certain nozzle tip (referred to as type A). Here, the vertical axis shows the negative (−) pressure above the zero point (pressure “0”) and the positive (+) pressure below it.

10 and 11 are shown in FIG.
It is a timing diagram showing a control procedure when performing three-dispensing. Here, the Z axis indicates pulse motor control for moving up and down the dispensing nozzle 25 (see FIG. 1). In addition, the control waveform is trapezoidal because it is a control that gradually increases the rotation speed of the pulse motor from a low speed, continues a constant high-speed motion, and then gradually decreases the rotation speed. It is shown in the figure. Since such trapezoidal control is a known motor driving technique, detailed description will be omitted.

The S-axis indicates the process of controlling the liquid suction and liquid discharge of the nozzle tip 13 by moving the plunger 44 (see FIG. 1) up and down. As described above, the upper and lower sides of the plunger 44 can be controlled by switching the rotation direction (CW, CCW) of the pulse motor 51.

In the Z-axis and S-axis trapezoidal control described above, the portion indicated by the two lines (α1 in FIG. 10 and FIG.
1 α3, α5, β2, β3) means that the pulse motor is driven by a preset number of pulses. For example, since the S-axis control motor 51 of the present embodiment rotates 0.36 degrees per pulse, it is possible to calculate the suction amount / discharge amount per pulse.

Next, the operation of the 1: 3 dispensing will be specifically described with reference to FIGS.

First, as shown in FIG. 10, the dispensing nozzle 25 is lowered by a predetermined amount (α1), and is stopped for a fixed period (T1). Next, while inhaling from the dispensing nozzle tip 13 (β1), the dispensing nozzle 25 itself is lowered (α2). At this time, when the nozzle tip 13 reaches the liquid surface, the pressure sensor 61 causes a negative pressure peak (a in FIG. 9).
Point) is detected. Therefore, in response to the output of this sensor, the descent of the nozzle tip 13 is stopped and the suction of the nozzle tip 13 is stopped. The above operation is the liquid level sensing operation (FIG. 10).

Next, as shown in FIG. 11, the dispensing nozzle 25 is lowered by a predetermined amount (α3), whereby the tip of the nozzle tip 13 is submerged in the liquid. Then, the suction of the prescribed amount from the nozzle tip 13 is started (β2).
At the same time, the dispensing nozzle 25 is lowered (α4).
This is a control for always immersing the nozzle tip 13 in the liquid, because the liquid surface also descends as the liquid is sucked into the nozzle tip 13.

After the step of sucking the prescribed amount of liquid (point b in FIG. 9) is completed, a predetermined rest time (T2) is provided. This eliminates the deviation between the detected value of the pressure sensor and the actual movement of the liquid.

Next, the dispensing nozzle 25 is raised by a predetermined amount (α5). At this time, as shown in FIG.
Since surface tension is generated at the tip of the nozzle tip 13, point c in FIG. 9 is generated when this is cut. Further, point d in FIG. 9 is an impact generated as the dispensing nozzle 25 rises.

When the dispensing nozzle 25 stops rising, the tip of the nozzle tip 13 is positioned in the air. Therefore, a predetermined amount of inhalation is performed at that position. By this,
The tip of the nozzle tip 13 contains air as shown in FIG. This air gap will be referred to herein as an "air gap." The point e in FIG. 9 is
It shows the pressure change that occurs when the "air gap" is formed. The reason for forming such an air gap is to prevent the liquid sucked from the tip of the nozzle from leaking out as the nozzle tip 13 is transported in the horizontal direction. Point f in FIG. 9 represents a pressure change that occurs when the nozzle tip 13 is conveyed.

When the nozzle tip 13 is horizontally conveyed to a predetermined position and the first discharge is performed, the detection value of the pressure sensor changes from point g to point h in FIG.

After that, the air gap is formed again for the next dispensing work (point i in FIG. 9). Then, the nozzle tip 13 is transported in the horizontal direction and stopped at the second dispensing position. The detected value of the pressure sensor at this time is indicated by point j in FIG. By the second ejection from the nozzle tip 13, the detection value of the pressure sensor changes up to point k in FIG. Then, the air gap is formed again in preparation for the third dispensing work (point l in FIG. 9).

Thereafter, the nozzle tip 13 is conveyed in the horizontal direction and stopped at the third dispensing position. The detection value of the pressure sensor at this time is indicated by point m in FIG. By the third ejection from the nozzle tip 13, the detection value of the pressure sensor changes up to n points.

As described above, the 1: 3 dispensing operation is completed, the air gap is formed again (point O in FIG. 9), and then the dispensing head 24 having the dispensing nozzle 25 mounted thereon is returned to the home position.

The point to be noted in the 1: 3 dispensing work described above is the detection value of the pressure sensor before discharge (point g in FIG. 9,
j point, m point). That is, the pressure detection value immediately before the first discharge is g point, and the pressure detection value immediately before the second discharge is j.
Point, the pressure detection value immediately before the third discharge is represented by point m.

From this, although the pressure detection values immediately before the second and third discharges (points j and m in FIG. 9) are almost the same, the pressure detection values immediately before the first discharge (FIG. 9). 9 g
It is found that the point) has a value that is far from the above two detected pressure values.

Therefore, as a result of replacing the nozzle tip 13 with another type (type B) and again performing 1: 3 dispensing under the same conditions, a pressure detection value as shown in FIG. 13 was obtained. It was Here, point a'in FIG. 13 is a point at which the liquid level is sensed, point e'is a point at which the air gap is formed after the liquid is sucked into the nozzle tip 13, and point g'is the pressure immediately before the first discharge. The point indicating the detected value, the point i ′ indicates the air gap formation after the completion of the first dispensing, j ′
The point indicates the pressure detection value immediately before the second discharge,
Point l'indicates the formation of an air gap after the completion of the second dispensing, point m'indicates the pressure detection value immediately before the third ejection, and point O'indicates when the dispensing head 24 is returned to the home position. This is a point showing the formation of the air gap.

Also in FIG. 13, the pressure detection value (g 'point) immediately before the first discharge is far from the pressure detection values (j' point, m'point) immediately before the second and third discharges. I understand.

From FIG. 9 and FIG. 13 described above, both are 1
The pressure detection value (g point and g'point) immediately before the second discharge is
It was found that the pressure detection values after the second time were significantly different.

Therefore, the results shown in FIGS. 7 and 8 (1
9 and 13 (only the pressure detection value immediately before the first ejection is different from that of the second and subsequent ejections). , The following conclusions were obtained.

That is, "By making the pressure detection value immediately before the first discharge the same as that of the second and subsequent discharges, it is possible to eliminate the variation that has occurred during the first discharge."
That is the conclusion.

In order to prove such a conclusion, the control shown in FIG. 14 was performed, and in the above-mentioned 1: 3 dispensing, each discharge amount could be kept within the allowable range (± 2%).

The control procedure in FIG. 14 will be described below.

FIG. 14 is performed in place of the suction operation described in FIG. 11, and should be performed after the liquid level sensing operation shown in FIG.

To perform the suction operation of FIG. 14, first, the nozzle tip 13 is lowered by a predetermined amount (α10), and the tip of the nozzle tip 13 is embedded in the liquid. This control is the same as α3 in FIG.

Next, suction is performed into the nozzle tip 13 (β10), and the nozzle tip 13 itself is also lowered (α11) in order to cope with the liquid level drop. This control is the same as β2 and α4 in FIG.

After that, a certain rest period (T10) is provided. This is also the same as T2 in FIG.

Next, a predetermined amount is ejected with the tip of the nozzle tip 13 buried in the liquid (β11). Hereinafter, the control in β11 will be referred to as “return control”. By performing the above-mentioned return control, the pressure detection value at the dispensing nozzle 25 becomes the same as when the first discharge was performed (see point h in FIG. 9).

Thereafter, a certain rest period (T11) is provided, and the nozzle tip 13 is raised by a predetermined amount (α1
2). As a result, the tip of the nozzle tip 13 is exposed in the air, and an air gap is formed in preparation for the first conveyance (β12). As a result, the detected pressure value becomes equal to the values shown at points j and m in FIG.

Subsequent transportation and ejection are performed as described above.

Thus, it becomes possible to keep all the ejection amounts within the allowable range.

The suction operation shown in FIG. 14 is not limited to the suction operation shown in FIG. 14, and the suction operation shown in FIG. 15 can be performed.

In FIG. 15, the return control (β11) shown in FIG. 14 is executed.
The difference is that the air gap is formed before the step (.beta.21 in FIG. 15). The control in FIG. 15 will be described in more detail as follows.

Α20 in FIG. 15 corresponds to α10 in FIG.

Β20 in FIG. 15 corresponds to β10 in FIG.

Α21 in FIG. 15 corresponds to β11 in FIG.

T20 in FIG. 15 corresponds to T10 in FIG.

At α22 in FIG. 15, the nozzle tip 13 is raised by a predetermined amount, whereby the tip of the nozzle tip 13 is exposed in the air. Next, the air gap is formed by suctioning into the nozzle tip 13 (β21).

After that, the nozzle tip 13 is lowered again by a predetermined amount, and the tip of the nozzle tip 13 is submerged in the liquid (α23). Then, in that state, the return control is performed (β22). This β22 corresponds to β11 in FIG.

T21 in FIG. 15 corresponds to T11 in FIG.

Α24 in FIG. 15 corresponds to α12 in FIG.

Β23 in FIG. 15 corresponds to β12 in FIG.

FIG. 16 is a block diagram of FIG. 10, FIG. 11, FIG.
5 shows a hardware configuration for performing the control shown in FIG.
In the figure, 100 is a CPU (central processing unit),
The control described below is executed. A keyboard 102 is used to specify the number of pulses applied to the pulse motor, the rotation speed of the pulse motor, and the discharge / suction amount. 104 is RAM
(Random access memory), and the keyboard 102
It is used as a buffer area for data input from or a work area for the CPU. Reference numeral 106 denotes a ROM (Read Only Memory), which stores the control procedure shown in FIGS. 17 to 21 and other control procedures. 108 is
A pulse motor 9 for controlling the raising and lowering of the dispensing head 24
0 driver. Reference numeral 110 is a driver of the pulse motor 51 that controls the suction and discharge of the nozzle tip 13. Reference numeral 112 is a driver for the pulse motors 92A and 92B that controls the horizontal movement of the dispensing head 24. Reference numeral 61 is the pressure sensor shown in FIG.

FIG. 17 shows one of the main flows to be executed by the CPU. In this figure, STEP 1 is a liquid level sensing sequence, the details of which are shown in FIG. STEP 2 is an inhalation sequence, and various inhalation sequences are detailed in FIGS. 19 to 21. STEP
Reference numeral 3 denotes a dispensing sequence, which carries out the transport / discharge control for performing the 1: N dispensing described above.

FIG. 18 is a flow chart showing the liquid level sensing sequence. The reference numerals of the respective steps shown in the figure are made to coincide with the reference numerals of the respective controls described in FIG. Therefore, the content of each step is as described with reference to FIG. 10, and will not be described in detail here.

FIG. 19 is a flow chart showing the first inhalation sequence, which corresponds to the control described in FIG. FIG. 20 is a flowchart showing the second inhalation sequence, which corresponds to the control described in FIG. Figure 21
Is a flow chart showing a third inhalation sequence, which corresponds to the control described in FIG. 15. These, FIG.
The reference numerals of the steps shown in FIG. 21 are respectively those in FIG.
Since this is the same as the reference numeral described in FIGS. 14 and 15, it will not be described in detail here.

[0095]

As described above, according to the present invention, when a certain liquid is continuously dispensed into a plurality of containers,
The liquid sucked into the dispensing nozzle is not immediately dispensed into a plurality of containers, but the liquid sucked into the dispensing nozzle tip is discharged into the container again, and as a result, the first time Since it is possible to cause the same state as when the dispensing was performed in the nozzle tip before starting the dispensing, liquid can be inhaled collectively from a single container and continuously used for multiple containers. When dispensing is performed, it is possible to accurately control the discharge amount during all dispensing.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view showing an internal structure of a dispensing head in an embodiment of a sampling and dispensing apparatus according to the present invention.

FIG. 2 is a perspective view showing an appearance of a sampling and dispensing device in this embodiment.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

5 is a cutaway view taken along the line VV in FIG.

FIG. 6 is a graph schematically showing the relationship between the operation of the ram and the plunger and the detection value of the pressure sensor when the liquid to be sampled is inhaled in the present embodiment.

FIG. 7 is a diagram showing the results of a dispensing accuracy test.

FIG. 8 is a diagram showing the results of a dispensing accuracy test.

FIG. 9 is a diagram showing a pressure detection value when performing 1: 3 dispensing.

FIG. 10 is a timing diagram showing a liquid level sensing operation.

FIG. 11 is a timing chart showing a first inhalation operation.

FIG. 12 is an explanatory diagram showing a state of a tip of a nozzle tip 13.

FIG. 13 is a diagram showing a pressure detection value when performing 1: 3 dispensing.

FIG. 14 is a timing chart showing a second suction operation.

FIG. 15 is a timing chart showing a third inhalation operation.

FIG. 16 is a block diagram showing a hardware configuration according to an embodiment of the present invention.

FIG. 17 is a flowchart showing a control procedure in this embodiment.

FIG. 18 is a flowchart showing a control procedure in this embodiment.

FIG. 19 is a flowchart showing a control procedure in this embodiment.

FIG. 20 is a flowchart showing a control procedure in this embodiment.

FIG. 21 is a flowchart showing a control procedure in this embodiment.

[Explanation of symbols]

 11 Column 12 Working Table 13 Nozzle Tip 14 Chip Rack 15 Chip Storage Box 16 Supply Container 17 Sample Rack 18 Test Container 19 Assay Rack 20 Arm 21 Cross Beam 22 Saddle 23 Ram 24 Dispensing Head 25 Dispensing Nozzle 26 Head Bracket 27 Head Holder 28, 29 Guide rod 30 Upper casing holder 31 Lower casing holder 32 Set screw 33 Casing 34 Compression coil spring 35 Bush 36 Buffer ring 37 Magnetic sensor 38 Buffer ring 39 Fitting part 40 Set screw 41 Pump chamber 42 Passage 43 Feed screw shaft 44 Plunger 45 Non-rotating pin 46 Set screw 47 Pin guide hole 48 Pin bracket 49 Feed nut 50 Bearing 51 Stepping motor (pulse motor) 52 Strut 53 Mo Rotary shaft 54 toothed drive pulley 55 toothed driven pulley 56 toothed belt 57 tension roller 58 optical switch 59 switch bracket 60 connection pipe 61 pressure sensor 62 communication pipe

Claims (2)

[Claims] 1. A dispensing device for inhaling from a single liquid container and delivering a prescribed amount to a plurality of containers by using a dispensing nozzle tip that can be moved back and forth, left and right, and up and down respectively. Then, after inhaling a predetermined amount by the dispensing nozzle tip,
A dispenser comprising a control means for discharging a part of the sucked liquid again into the single liquid container from the dispense nozzle tip. 2. The pump chamber according to claim 1, further comprising: a pump chamber formed on an upper portion of a dispensing nozzle for mounting the dispensing nozzle tip, and the nozzle tip formed on a lower portion of the dispensing nozzle. A passage that communicates the inside with the pump chamber; a plunger that slidably fits into the pump chamber; a plunger lifting drive pulse motor that raises and lowers the plunger; and a rotation direction of the pulse motor that is predetermined. A dispensing device comprising: a driving unit that controls in accordance with a sequence.