Dispensing device, automatic analysis device, dispensing method

Abstract

The present application aims to provide a dispensing device capable of preventing bubbles from flying out of a nozzle and achieving high-precision dispensing even if the nozzle is moved at high speed toward a liquid surface and decelerated / stopped at high acceleration. The dispensing device of the present application starts suction of a liquid during a period from when a nozzle starts to descend toward a liquid surface of the liquid to when an end portion of the nozzle contacts the liquid surface and until the nozzle stops descending (see Fig. 6).

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid dispensing device. BACKGROUND

[0002] An automatic analysis device is a device that performs quantitative analysis or qualitative analysis of a specific component included in a biological sample such as blood or urine, and is indispensable in current diagnoses due to reproducibility of analysis results, processing speed, and the like. In recent years, in addition to seeking improvement in processing capacity, there is also a demand for reduction in the amount of reagent used in analysis, and thus a liquid dispensing device mounted on an automatic analysis device is required to dispense a sample / reagent at high speed and high precision.

[0003] A liquid dispensing device of an automatic analysis device generally uses a liquid level detection sensor to detect contact of a nozzle with a liquid when aspirating a sample / reagent that is a dispensing target, and aspirates while immersing the nozzle into the liquid to a certain extent. The liquid level detection sensor improves cleaning efficiency by limiting the immersion extent of the nozzle, prevents cross contamination and carryover when dispensing other types of liquid, and shortens the cleaning time to contribute to improvement in analysis processing capacity. As a liquid level detection method, there are a pressure method described in Patent Literature 1 and an electrostatic capacity method described in Patent Literature 2.

[0004] Sometimes, false detection occurs at a place where the liquid level is different due to a bubble or interference noise, causing poor liquid aspiration. In order to avoid such false detection and maintain high dispensing precision, a method of comparing a liquid level detection height with a previous value described in Patent Literature 3 and a method of detecting a liquid level based on a difference from a background signal not holding a liquid described in Patent Literature 4 have been proposed.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Laid-Open No. 7-055819

[0008] Patent Literature 2: Japanese Patent No. 5703376

[0009] Patent Literature 3: Japanese Patent Application Laid-Open No. 2007-032285

[0010] Patent Literature 4: Japanese Patent Application Laid-Open No. 2015-184126 SUMMARY

[0011] PROBLEMS TO BE SOLVED BY THE INVENTION

[0012] To improve processing capacity, high-speed operation is required for various actions, such as nozzle movement. Furthermore, to minimize cleaning time, the immersion range of the nozzle in the sample or reagent needs to be limited. Therefore, the nozzle's descent speed to the liquid surface must be high, while the distance from reaching the liquid surface to stopping the nozzle is limited. As a result, the acceleration during nozzle deceleration increases, and due to inertia, the fluid inside the nozzle is compressed, creating a risk of air or other contaminants being ejected from the nozzle tip. If air is ejected, there is a possibility of liquid intrusion at this point, drawing in excess liquid compared to the intended amount. This results in errors in the dispensing volume.

[0013] The present invention was made in response to the aforementioned problem, and aims to provide a dispensing device that can prevent air bubbles from flying out of the nozzle and achieve high-precision dispensing even when the nozzle is moved at high speed toward the liquid surface and decelerated / stopped with high acceleration.

[0014] Solution for solving the problem

[0015] The dispensing device of the present invention begins to draw in the liquid after the nozzle begins to descend toward the liquid surface, and during the period from when the end of the nozzle contacts the liquid surface until the descent of the nozzle stops.

[0016] Invention Effects

[0017] According to the dispensing device of the present invention, liquid is drawn in during the period when the nozzle reaches the liquid surface and decelerates from high speed. Therefore, even if the nozzle stops and the fluid inside is compressed, air at the tip of the nozzle can be retained inside the nozzle, preventing excessive liquid from being drawn in. Other issues, structures, and effects beyond the above will become clear from the following description of embodiments. Attached Figure Description

[0018] Figure 1 This is an overall structural diagram of the automatic analysis device 10 according to Embodiment 1.

[0019] Figure 2 This is a structural diagram of the dispensing device according to Embodiment 1.

[0020] Figure 3 This is a flowchart illustrating the previous betting order as a comparative example.

[0021] Figure 4 It is shown Figure 3 A side view of the movement of nozzle 113 in the flowchart.

[0022] Figure 5 This is a flowchart illustrating the injection sequence of Implementation Method 1.

[0023] Figure 6 It is shown Figure 5 A side view of the movement of nozzle 113 in the flowchart.

[0024] Figure 7A Fig. 2 is a diagram showing a structure example of a liquid level measuring section of the automatic analysis device 10 according to Embodiment 2.

[0025] Figure 7B Fig. 2 is a diagram showing a structure example of a liquid level measuring section of the automatic analysis device 10 according to Embodiment 2.

[0026] Figure 8 Fig. 4 is a flowchart illustrating a dispensing order of Embodiment 2. DETAILED DESCRIPTION

[0027] <Embodiment 1>

[0028] Figure 1 Fig. 1 is a diagram showing the overall structure of the automatic analysis device 10 according to Embodiment 1. The automatic analysis device 10 is provided with the following: a sample container 100 that houses a sample; a sample rack 101 that is provided with a plurality of sample containers 100; a reagent holder 102 that houses a reagent; a reagent disk 103 that is provided with a plurality of reagent holders 102; a reaction unit 104 that mixes a sample and a reagent to become a reaction solution; a unit disk 105 that is provided with a plurality of reaction units 104; a sample dispensing mechanism 106 that is capable of moving a sample from inside the sample container 100 to inside the reaction unit 104; a reagent dispensing mechanism 107 that is capable of moving a reagent from inside the reagent holder 102 to inside the reaction unit 104; a stirring unit 108 that stirs a sample and a reagent inside the reaction unit 104 and mixes them; a measuring unit 109 that irradiates light to a reaction solution inside the reaction unit 104 and receives the obtained light; a cleaning unit 110 that cleans the reaction unit 104; a control section 111 that controls each part provided in the automatic analysis device 10; and a storage section 112 that stores parameters of the control, data measured.

[0029] The analysis of the amount of components included in the sample is performed in the following procedure. First, the sample in the sample container 100 is dispensed into the reaction unit 104 by the sample dispensing mechanism 106. Next, the reagent in the reagent holder 102 is dispensed into the reaction unit 104 by the reagent dispensing mechanism 107. Then, the sample and the reagent in the reaction unit 104 are stirred by the stirring unit 108 to become a reaction solution. If necessary, multiple reagents are additionally dispensed into the reaction unit 104 by the reagent dispensing mechanism 107. At the time of dispensing, the sample container 100, the reagent holder 102, and the reaction unit 104 are moved to a prescribed position by the transport of the sample rack 101, the rotation of the reagent disk 103, and the rotation of the unit disk 105. After the reaction is completed, the reaction unit 104 is cleaned by the cleaning unit 110 and the subsequent analysis is performed. The absorbance of the reaction solution is measured by the measuring unit 109, and the measurement result is stored as absorbance data in the storage section 112. The control section 111 uses the absorbance data and analyzes the amount of components based on the calibration curve data and the Lambert-Beer law.

[0030] Figure 2 is a configuration diagram of the dispensing device of Embodiment 1. This dispensing device can be applied to both the sample dispensing mechanism 106 and the reagent dispensing mechanism 107. An arm 114 that holds a nozzle 113 and can be rotationally driven is provided on a shaft 115 that can be driven up and down. The nozzle 113, a pressure sensor 116, and a syringe pump 117 are connected via a pipe 118. The dispensing flow path is configured such that the front end side is open to the nozzle 113, and the base side can be opened / closed by an electromagnetic valve 119. A liquid level detection sensor 120 is connected to the nozzle 113. At the time of dispensing a liquid, the front end of the nozzle 113 is immersed in the sample / reagent based on the signal of the liquid level detection sensor 120, the electromagnetic valve 119 is closed, and the liquid (sample, reagent) is sucked / pumped out by the syringe pump 117. After the dispensing operation is completed, the electromagnetic valve 119 is opened from the base side and cleaning water is supplied. The control section 111 controls the reception of the sensor signal and the transmission of the motor drive signal. The storage section 112 can store drive conditions and the like for this control.

[0031] Figure 3 is a flowchart illustrating a conventional dispensing sequence as a comparative example. This flowchart starts when system water is supplied into the nozzle 113 from the base side and air in the segment is sucked. In S301, the nozzle 113 is lowered toward the liquid surface. In S302, the control section 111 monitors the signal of the liquid level detection sensor 120 connected to the nozzle 113, and S301 is repeated until the liquid level detection signal is received. When the front end of the nozzle 113 reaches the liquid surface, the nozzle 113 is immersed in the liquid by a predetermined distance P dip (S303). When the lowering of the nozzle 113 is stopped (S304), the pump sucks the target suction amount V T (S305).

[0032] Figure 4 is a side view showing the action of the nozzle 113 in the flowchart of Figure 3 Here, the procedure of lowering the nozzle 113 to the liquid level of the sample 122 and performing suction in the sequence of dispensing the sample 122 entering the sample container 100 to the reaction unit 104 is shown.

[0033] In (a) of Figure 4 , the nozzle 113 is filled with the system water 121. In (b) of Figure 4 , the segment air 123 is sucked. From here, the flowchart of Figure 3 , in S301, the nozzle 113 is lowered toward the liquid level of the sample 122. In S302, the control section 111 monitors the signal of the liquid level detection sensor 120 connected to the nozzle 113, and repeatedly performs the lowering of S301 until the liquid level detection signal is received.

[0034] When the nozzle 113 reaches the liquid level of the sample 122 as in (c) of Figure 4 , in S302, the control section 111 receives the liquid level detection signal, and proceeds to S303. In S303, the nozzle 113 is further lowered by a distance P dip . In this interval, in order to prevent the misalignment of the motor, the lowering speed is generally decelerated. Figure 4 (d) of corresponds to S303 of Figure 4

[0035] In S304, the nozzle 113 is stopped. Figure 4 (e) of corresponds to S304, and the front end of the nozzle 113 is immersed by a depth P dip . This immersion amount P dip is generally set so as not to cause air suction due to lowering of the liquid level or the like when the sample 122 is sucked from the nozzle 113, and so as not to come off the position of contact with the cleaning liquid at the time of cleaning.

[0036] In the case of improving the dispensing processing capacity, the lowering speed of the nozzle 113 in S301 can be cited as one of the means. On the other hand, in order to maintain the cleaning efficiency of the nozzle 113, it is necessary to limit the increase of the immersion amount P dip in S303. When the high-speed lowering and the immersion amount maintenance are performed simultaneously, the acceleration change at the time of stopping of the nozzle increases from S301 to S302, and therefore, when the nozzle 113 is stopped, the system water 121 in the nozzle 113 pushes out the segment air 123 under the action of inertia, and the leakage air 124 is generated which leaks out from the front end of the nozzle 113 as in (f) of Figure 4 . Also, sometimes the leakage air 124 is separated from the segment air 123 by flying out from the nozzle 113 as in (g) of Figure 4 .​

[0037] When the system water 121 in the nozzle 113 sloshes and converges due to inertia, as... Figure 4 (h) air leaks out 124 to the outside of nozzle 113, and the volume V of the leaked air 124 is... air An equal amount of the intrusion sample 125 is kept inside the nozzle.

[0038] Subsequently, in S305, the injection pump 117 is used to aspirate V, which is the original sample 122. T Thus, as Figure 4 (i) that way, keep V in nozzle 113 air +V T Sample 122.

[0039] exist Figure 4 In (j), the nozzle 113 is moved to the reaction unit 104, and in Figure 4 In the case where all the amount of sample 122 held in nozzle 113 is ejected along with a portion of the system water 121 in reaction unit 104, sample 122 is excessively ejected V. air The amount. After the sample 122 is ejected, it is usually as follows: Figure 4 Clean the inside and outside of nozzle 113 as in (l) and proceed to the next sample dispensing process.

[0040] As described above, when the acceleration change at the point of stopping due to the increased descent speed of nozzle 113 is accompanied by the separation / release of leaking air 124, it sometimes causes excessive intrusion into the sample 125 and results in an error in the dispensing volume. Based on experimental verification, the deceleration acceleration at the point of stopping the descent is set to 24000 mm / s. 2 Under the above conditions, the separation / release of leaked air 124 was observed. In addition, considering the possibility that the shaking of the system water 121 when the descent of nozzle 113 stops, a portion of the system water 121 may mix into the sample 122 that should be disconnected by segmented air 123, causing the sample 122 to become thinner.

[0041] In view of the problems of conventional injection sequence as described above, the present invention controls the suction action of sample 122 in a manner that prevents segmented air 123 from leaking out of nozzle 113, thereby suppressing injection volume error.

[0042] Figure 5 This is a flowchart illustrating the dispensing sequence of Embodiment 1. This flowchart is implemented by controlling each part through the control unit 111. (The following will describe...) Figure 8 The same applies to China.

[0043] This flowchart is started when the system water 121 is supplied into the nozzle 113 from the base side and the segmental air 123 is sucked. In S501, the nozzle 113 starts to descend toward the liquid surface of the sample 122, and in S502, S501 is repeated until the control section 111 receives the liquid surface detection signal of the liquid surface detection sensor 120. In S503, the sample 122 of volume V C is sucked by the syringe pump 117. At the same time, in S504, the nozzle 113 is descended by the distance P dip . When the descent of the nozzle 113 is stopped (S504), the liquid amount V S is sucked by the pump (S505). When the target suction amount is set to V T , V S = V T - V C .

[0044] Figure 6 is a side view schematic diagram showing the action of the nozzle 113 in the flowchart of Figure 5 . In (a) of Figure 6 , the nozzle 113 is filled with the system water 121. Next, in (b) of Figure 6 , the segmental air 123 is sucked. From this, the flowchart of Figure 5 is started. In S501, the nozzle 113 descends toward the liquid surface of the sample 122, and in S502, S501 is repeated until the control section 111 receives the liquid surface detection signal of the liquid surface detection sensor 120.

[0045] When the nozzle 113 reaches the liquid surface of the sample 122 as in (c) of Figure 6 , the control section 111 receives the liquid surface detection signal in S502, and proceeds to S503. In S503, the sample 122 of volume V C is sucked by the syringe pump 117. At the same time, in S504, the nozzle 113 is descended by the distance P dip . By sucking the sample 122 in S503, the sample 122 is sucked into the nozzle 113 during the descent of the nozzle 113 as in (d) of Figure 6 .

[0046] When the descent of the nozzle 113 is stopped in S505, the sample 131 is prepared in a state where the front end of the nozzle 113 is dipped by the depth P dip , and the sample 131 is held in the nozzle 113 in the amount V C as in (e) of Figure 6 .

[0047] When the nozzle 113 is stopped after descending at high speed, the sample 131 is held in the nozzle 113 in the amount V Figure 6As in (f), under the influence of inertia, the system water 121 inside the nozzle 113 compresses the segmented air 123. Consequently, a portion of the pre-sample 131 held at the tip of the nozzle 113 is released out of the nozzle, but the segmented air 123 remains in the nozzle 113. Therefore, it will not be as... Figure 4 The segmented air 123 is discharged from the nozzle 113 in the manner of (g).

[0048] like Figure 6 As in (g), the preparatory sample 131, compressed by the system water 121, flows into the nozzle 113 due to the agitation of the system water 121. During the agitation of the system water 121, the preparatory sample 131 repeatedly enters and exits the nozzle 113. When the agitation of the system water 121 ceases, as... Figure 6 (h) and so on, returning to the state where the volume V is maintained within the nozzle 113. S The state of the preparatory sample 131.

[0049] In S506, the syringe pump 117 is used to aspirate V. S Sample 122. At this point, the target attraction amount of the final sample 122 is V. T In this case, let's set it to V. S =V T -V C Thus, as Figure 6 (i) that way, keep V in nozzle 113 T Sample 122.

[0050] After that, Figure 6 In (j), the nozzle 113 is moved to the reaction unit 104, and in Figure 6 The entire amount of sample 122 held at nozzle 113, along with a portion of system water 121, is ejected from (k) to dispense the target amount V into reaction unit 104. T Sample 122. After sample 122 is ejected, as... Figure 6 Clean the inside and outside of nozzle 113 as in (l) and proceed to the next sample dispensing process.

[0051] As described above, by drawing the preparatory sample 131 until the nozzle 113 stops descending, it is possible to prevent segmented air 123 from leaking out of the nozzle 113 and achieve error-free dispensing.

[0052] The pump suction action of S503 does not necessarily need to be completed before the nozzle of S505 stops descending, but it needs to be completed before the system water 121 squeezes the prepared sample 131 to its maximum extent (i.e., becomes Figure 6 Before the state of (g), the pre-extracted sample 131 with an extrusion amount exceeding the specified value is attracted. That is, V C It needs to be above this extrusion volume.

[0053] existFigure 5 The diagram shows an example of performing two suctions based on the syringe pump 117 in S503 and S506, but the target suction volume V can also be suctioned once in S503. T However, in the automatic analysis device 10, the liquid pressure is typically measured by the pressure sensor 116 when the sample 122 is drawn into the nozzle 113, and based on this pressure value, it is determined whether fibrous materials or the like in the sample are blocked in the nozzle 113. To accurately perform the pressure measurement, it is preferable to measure the pressure when the nozzle 113 is stationary. Therefore, in the case of performing a blockage determination, it is preferable to... Figure 5 That would divide the suction process into two steps, and pressure measurement would be performed in S506.

[0054] <Implementation Method 1: Summary>

[0055] In the automatic analysis device 10 of this embodiment 1, after the nozzle 113 begins to descend toward the liquid surface, and from the point where the end of the nozzle 113 contacts the liquid surface until the descent of the nozzle 113 stops, liquid suction begins. Thus, as... Figure 6 As shown in (g), it is possible to prevent the segmented air 123 inside the nozzle 113 from flying out of the nozzle 113 when the nozzle 113 stops descending. Therefore, it is possible to suppress the intrusion into the sample 125 and improve the dispensing accuracy.

[0056] In this embodiment 1, the automatic analysis device 10 attracts volume V in S503. C The liquid. V C To ensure that the amount of air squeezed into the prepared sample 131 exceeds the maximum amount when the nozzle 113 stops descending. As a result, segmented air 123 can be reliably maintained into the nozzle 113 when the nozzle 113 stops descending.

[0057] <Implementation Method 2>

[0058] Figure 7A and Figure 7B This diagram illustrates a structural example of the liquid level measuring unit included in the automatic analysis apparatus 10 according to Embodiment 2 of the present invention. In this Embodiment 2, the liquid level detection sensor 120 described in Embodiment 1 is used instead of, or in conjunction with, the liquid level detection sensor 120 described in Embodiment 1. Figure 7A Image sensor 146 Figure 7B The displacement sensor 147. Other structures are the same as in Embodiment 1.

[0059] As the liquid level detection sensor 120, a capacitive liquid level detection sensor is most commonly used. The image sensor 146, the displacement sensor 147 can measure the liquid level height in a non-contact manner, and thus does not require movement, contact of the nozzle at the time of liquid level measurement, and can perform measurement in parallel with the nozzle movement mechanism. Therefore, reduction in processing speed and risk of contamination between samples / reagents accompanying movement and cleaning operations can be avoided. The image sensor 146, the displacement sensor 147 are desirably provided on the conveyance path of the sample container 100 or at a position at which the nozzle 113 sucks the sample 122. In addition to this, as long as the liquid level height can be measured in parallel with the nozzle movement (i.e., simultaneously with the operation of the nozzle movement mechanism), it is not limited to the above-described means.

[0060] Figure 8 is a flowchart illustrating the dispensing sequence of Embodiment 2. In S801, the liquid level height of the sample 122 is measured, and the distance P from the nozzle 113 to the liquid level is measured. L In S802, the time T to reach the liquid level when the nozzle 113 is lowered to the sample 122 is calculated. L In S803, the lowering of the nozzle is started.

[0061] In S804, the nozzle 113 is lowered by the distance P L In S805, the nozzle 113 is lowered by the distance P dip S804 to S805 can also be executed as a series of operations. S803 to S804 can also lower the nozzle until the liquid level detection sensor 120 detects contact of the nozzle 113 with the liquid level.

[0062] S806 to S807 are executed in parallel with S804 to S805. In S806, the nozzle 113 is stood by for a time T L from the start of lowering. It is assumed that by this standing by, the nozzle 113 reaches the liquid level. In S807, the sample 122 is sucked by the syringe pump 117, and thus the preliminary sample 131 is held in the nozzle 113.

[0063] In S806, the lowering of the nozzle 113 is stopped. At this time, even if the system water 121 presses the segment air 123, the segment air 123 remains inside the nozzle 113. By sucking the sample 122 by the syringe pump 117 in S809 by the volume V S , the sample 122 of the target suction amount V T can be held in the nozzle 113. Hereafter, when the sample 122 held in the nozzle 113 is ejected to the reaction unit 104, dispensing of the target amount is completed.

[0064] <Embodiment 2: Summary>

[0065] The automatic analysis device 10 of this Embodiment 2 calculates the time T from the start of lowering of the nozzle 113 until reaching the liquid surface by measuring the liquid level of the sample 122 in advance L , and starts the suction after T L has elapsed. Thus, the time point at which the nozzle 113 reaches the liquid surface can be accurately estimated, and thus error-free dispensing operation can be achieved.

[0066] The automatic analysis device 10 of this Embodiment 2 measures the liquid level using the image sensor 146 and the displacement sensor 148, and thus, in the case where the structure in which the dispensing pump 117 is started by the signal of the liquid level detection sensor 120 is not provided, the suction operation can be performed during the period from the time at which the nozzle 113 reaches the liquid surface until the lowering is stopped, as in Embodiment 1.

[0067] In this Embodiment 2, instead of the standby time T L in S806, a control signal that indicates the movement distance P L of the movement mechanism that lowers the nozzle 113 can be counted. For example, in the case where the nozzle 113 is lowered using a stepping motor, the number of control pulses can be counted. In this case as well, the timing at which the nozzle 113 contacts the liquid surface can be estimated.

[0068] <MODIFICATION OF THE INVENTION>

[0069] The present application is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments are described in detail in order to easily understand the present application, and are not necessarily limited to the structures described. In addition, a part of the structure of one embodiment can be replaced with the structure of another embodiment, and in addition, the structure of one embodiment can be added with the structure of another embodiment. In addition, a part of the structure of each embodiment can be added / removed / replaced with another structure.

[0070] The control section 111 can be configured by a hardware such as a circuit device in which the function is installed, and can be configured by a software in which the function is installed executed by an arithmetic device such as a CPU. The storage section 112 can be configured by a storage device such as a hard disk device and a memory device.

[0071] In the above-described embodiments, the deceleration of the nozzle 113 is 24000 m / s 2The above can be calculated according to the set parameters of the automatic analysis device 10. For example, by the number of analyzed samples, the number of used reagents, the number of analysis processes, the liquid amount of each liquid, and the like, the allowable capacity determined for the automatic analysis device 10 is unique. That is, the values required for the lowering speed and the deceleration acceleration of the nozzle 113 can also be determined. The control section 111 sets the deceleration acceleration of the nozzle 113 in accordance with these set parameters, and thus can determine whether the deceleration acceleration thereof is 24000 m / s 2 The above.

[0072] In the above embodiment, other medium can be disposed between the liquids instead of the segmented air. In this case, if the deceleration acceleration of the nozzle 113 at the time of stopping is large, the medium also flies out, and thus the amount of flying out can be suppressed by applying the present application.

[0073] Explanation of Reference Numerals

[0074] 10: Automatic analysis device

[0075] 100: Sample container

[0076] 101: Sample rack

[0077] 102: Reagent holder

[0078] 103: Reagent disk

[0079] 104: Reaction unit

[0080] 105: Unit disk

[0081] 106: Sample dispensing mechanism

[0082] 107: Reagent dispensing mechanism

[0083] 108: Agitation unit

[0084] 109: Measurement unit

[0085] 110: Washing unit

[0086] 111: Control section

[0087] 112: Storage section

[0088] 113: Nozzle

[0089] 114: Arm

[0090] 115: Shaft

[0091] 116: Pressure sensor

[0092] 117: Syringe pump

[0093] 118: Pipe

[0094] 119 solenoid valve

[0095] 120 liquid level detection sensor

[0096] 121 system water

[0097] 122 sample

[0098] 123 segmented air

[0099] 124 leakage air

[0100] 125 intruding sample

[0101] 131 preliminary sample

[0102] 146 image sensor

[0103] 147 displacement sensor

Claims

1. A dispensing device that dispenses a liquid, characterized by comprising: a nozzle that sucks or ejects a liquid; and a moving mechanism that moves the nozzle, wherein the nozzle starts sucking the liquid during a period from when the nozzle starts descending toward a liquid surface of the liquid to when an end portion of the nozzle contacts the liquid surface and until the nozzle stops descending, after the nozzle contacts the liquid surface, and wherein the nozzle further sucks air into an inside of the nozzle before starting to suck the liquid.

2. A dispensing device that dispenses a liquid, characterized by comprising: a nozzle that sucks or ejects a liquid; and a moving mechanism that moves the nozzle, wherein the nozzle starts sucking the liquid during a period from when the nozzle starts descending toward a liquid surface of the liquid to when an end portion of the nozzle contacts the liquid surface and until the nozzle stops descending, after the nozzle contacts the liquid surface, and wherein the nozzle performs first sucking of the liquid from when the nozzle contacts the liquid surface to when the nozzle stops descending.

3. The dispensing device according to claim 2, characterized in that the nozzle sucks an amount of the liquid obtained by subtracting an amount of the liquid sucked by the first sucking from a target amount of the liquid to be sucked in the second sucking.

4. The dispensing device according to claim 1 or 2, characterized in that the dispensing device further comprises a liquid surface detection sensor that detects that the nozzle contacts the liquid, and wherein the nozzle starts sucking the liquid when the liquid surface detection sensor detects that the nozzle contacts the liquid.

5. The dispensing device according to claim 1 or 2, characterized in that the dispensing device further comprises a liquid surface measurement unit that measures a liquid surface height of the liquid in a container that contains the liquid before the nozzle sucks the liquid, and wherein the nozzle starts sucking the liquid after the nozzle moves a distance corresponding to the liquid surface height measured by the liquid surface measurement unit.

6. The dispensing device according to claim 5, characterized in that the liquid surface measurement unit is constituted by any one or a combination of a liquid surface detection sensor, an image sensor, and a displacement sensor, wherein the liquid surface detection sensor detects that the nozzle contacts the liquid, wherein the image sensor photographs the nozzle and the liquid, and wherein the displacement sensor detects displacement of the liquid surface or the nozzle.

7. The dispensing device according to claim 5, characterized in that the liquid surface measurement unit is capable of measuring the liquid surface height without contacting the liquid, and wherein the liquid surface measurement unit is capable of acting in parallel with the moving mechanism. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 8. The dispensing device according to claim 1 or 2, wherein the nozzle starts the suction of the liquid during a period from when the end of the nozzle contacts the liquid surface to when the descent of the nozzle stops, in a case where the deceleration of the nozzle at the time of the stop of the nozzle is 24000 mm / s2 or more.

9. An automatic analyzer that analyzes a sample of a liquid, the automatic analyzer comprising: a dispensing device that dispenses the liquid, the dispensing device comprising: a nozzle that suctions or ejects the liquid; and a moving mechanism that moves the nozzle, wherein the nozzle starts the suction of the liquid during a period from when the end of the nozzle contacts the liquid surface to when the descent of the nozzle stops, after the nozzle starts to descend toward the liquid surface.

10. An automatic analyzer that analyzes a sample of a liquid, the automatic analyzer comprising: a dispensing device that dispenses the liquid, the dispensing device comprising: a nozzle that suctions or ejects the liquid; and a moving mechanism that moves the nozzle, wherein the nozzle starts the suction of the liquid during a period from when the end of the nozzle contacts the liquid surface to when the descent of the nozzle stops, after the nozzle starts to descend toward the liquid surface, the nozzle performs a first suction of the liquid from when the nozzle contacts the liquid surface to when the descent of the nozzle stops, and the nozzle performs a second suction of the liquid after the nozzle stops the descent operation after the first suction.

11. The automatic analyzer according to claim 10, wherein the nozzle suctions an amount obtained by subtracting an amount of the liquid suctioned by the first suction from a target suction amount of the liquid, in the second suction.

12. A dispensing method that dispenses a liquid, the dispensing method comprising: starting the suction of the liquid during a period from when the end of a nozzle that suctions or ejects the liquid contacts the liquid surface to when the descent of the nozzle stops, after the nozzle starts to descend toward the liquid surface, and suctioning, during a period from when the suction of the liquid starts to when the descent of the nozzle stops, an amount of the liquid that is present inside the nozzle when the descent of the nozzle stops and that is discharged to the outside of the nozzle by shaking inside the nozzle.

13. A dispensing method that dispenses a liquid, the dispensing method comprising: starting the suction of the liquid during a period from when the end of a nozzle that suctions or ejects the liquid contacts the liquid surface to when the descent of the nozzle stops, after the nozzle starts to descend toward the liquid surface. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The nozzle performs a first suction of the liquid from a time when the nozzle contacts a liquid surface of the liquid to a time when the nozzle stops lowering, The nozzle performs a second suction of the liquid after the first suction is performed and after the nozzle stops the lowering action.

14. The method of claim 13, wherein The nozzle suctions an amount obtained by subtracting an amount of the liquid suctioned by the first suction from a target suction amount of the liquid in the second suction.

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