Dispensing device and probe state confirmation method

Abstract

The purpose of the present invention is to provide a dispensing device and probe state confirmation method which make it possible to ascertain a suitable replacement period for the probe, while suppressing a lowering of dispensing accuracy. In order to achieve this, the present invention provides a dispensing device comprising: a probe that suctions and discharges a liquid; a sensor that detects the contact of a tip of the probe; a drive unit that drives the probe in the vertical direction; and a control unit that controls the drive unit, wherein the control unit performs a confirmation operation for a length change of the probe by lowering the probe via the drive unit until contact with a prescribed reference surface forming a portion of the dispensing device is detected.

Description

Dispensing device and probe status check method

[0001] The present invention relates to a dispensing device equipped with a probe and a method for checking the state of the probe.

[0002] For example, analyzers generally use non-sealed specimen containers with open tops. However, in recent years, sealed specimen containers with stoppers, such as vacuum blood collection tubes, have become widely used, and there is a growing need for dispensing devices that can directly collect specimens from sealed specimen containers without opening them. When aspirating specimens from such sealed specimen containers, for example, Patent Document 1 discloses an automatic analyzer that monitors the penetration performance of a probe to determine when to replace the probe, because repeated piercing and dispensing of specimens from a specimen container with the same probe can deteriorate the probe's ability to penetrate the stopper due to wear or other reasons.

[0003] Japanese Patent Application Laid-Open No. 2015-102427

[0004] The technology described in Patent Document 1 only monitors the penetration performance of the probe, so even if it can reliably penetrate the stopper of a container, it does not necessarily guarantee accuracy when dispensing liquid. That is, according to the inventors' studies, when the stopper is repeatedly penetrated with the probe, the length of the probe becomes shorter, which causes variation in the operation of bringing the probe into contact with the reaction container when dispensing the sample, and as a result, it is possible that dispensing accuracy may decrease.

[0005] An object of the present invention is to provide a dispensing device and a method for checking the state of a probe that can determine the appropriate time to replace the probe while suppressing a decrease in dispensing accuracy.

[0006] In order to solve the above-mentioned problems, the present invention provides a dispensing device comprising a probe that aspirates and dispenses liquid, a sensor that detects contact of the tip of the probe, a drive unit that drives the probe in an up and down direction, and a control unit that controls the drive unit, in which the control unit confirms a change in the length of the probe by lowering the probe using the drive unit until it detects contact with a predetermined reference surface that forms part of the dispensing device.

[0007] According to the present invention, it is possible to provide a dispensing device and a method for checking the state of a probe that can determine the appropriate time to replace the probe while suppressing a decrease in dispensing accuracy.

[0008] 1 is a schematic diagram showing the main components of an automatic analyzer; a schematic diagram showing the configuration of a sample dispensing mechanism; a diagram explaining a mechanism for detecting contact of the tip of a sample dispensing probe; a diagram showing the positional relationship between a new sample dispensing probe, a sample dispensing probe with a worn tip, and a reference surface; a flowchart showing the operation of measuring the length of a probe before use; a time chart showing the operation of measuring probe length; a flowchart showing the operation of checking the probe status based on changes in probe length; a diagram showing the positional relationship with a reaction vessel when a pre-use probe and a post-use probe are lowered by a specified amount from the origin height; a schematic diagram showing the concept of correcting the probe lowering amount; a graph showing an example of the relationship between the amount of change in probe lowering amount and the number of dispenses; a diagram showing an example of a probe status confirmation screen; a diagram showing an example of a probe length setting screen.

[0009] The present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, the components (including element steps) are not necessarily essential unless otherwise specified or considered to be essential in principle.

[0010] In this embodiment, an automatic analyzer will be described as an example. Examples of automatic analyzers include automatic biochemical analyzers, automatic immunological analyzers, and automatic genetic analyzers. However, this is merely one example of an automatic analyzer, and it broadly includes devices that analyze samples by mixing samples such as plasma, serum, and urine with various reagents. For example, it also includes mass spectrometers used in clinical tests and coagulation analyzers that measure blood clotting time. The present invention can also be applied to composite systems combining these with automatic biochemical analyzers, automatic immunological analyzers, and the like, or to automatic analysis systems that utilize these.

[0011] [Configuration of the Automatic Analyzer] Fig. 1 is a schematic diagram showing the main configuration of the automatic analyzer. As shown in Fig. 1, the automatic analyzer includes a computer 1, a sample dispensing mechanism 2, a reagent refrigerator 5, a reagent dispensing mechanism 3, etc.

[0012] The computer 1 has an output unit, an input unit, and a storage unit. The output unit, such as a display, displays analysis results and alarms to the user. The input unit, such as a keyboard, allows the user to input characters and numbers to set the operating conditions of the device. The storage unit, such as a memory, stores analysis results and setting values. The user operates the input unit while viewing the output unit to request analysis and make various settings.

[0013] The specimen dispensing mechanism 2 aspirates specimens from specimen containers (not shown in FIG. 1 ) inserted into the device and dispenses them into reaction containers 4. The reagent refrigerator 5 keeps the reagents to be mixed with the specimens cool, and its top is closed with a lid. The reagent dispensing mechanism 3 aspirates the reagents through a hole in the lid of the reagent refrigerator 5 and dispenses them into reaction containers 4. The specimens and reagents dispensed into reaction containers 4 are mixed by a stirring mechanism (not shown), and a mixed liquid is prepared in reaction container 4. The absorbance and other properties of this mixed liquid are measured by an analysis unit (not shown), and a control unit (not shown) calculates the concentration of a predetermined component contained in the mixed liquid based on the measurement results. The control unit also controls the operation of each mechanism, such as the specimen dispensing mechanism.

[0014] [Configuration of the Dispensing Mechanism] Figure 2 is a schematic diagram showing the configuration of the sample dispensing mechanism. In addition to the sample dispensing probe 10, the sample dispensing mechanism 2 also includes a horizontal drive unit, a vertical drive unit, a syringe, and other components (not shown). Samples 11 are contained in sample containers 12, and one or more sample containers 12 are loaded on a sample rack 14 and transported to a dispensing position by a transport mechanism (not shown). In this embodiment, the sample containers 12 are assumed to be closed with stoppers 13, such as vacuum test tubes, but unstoppered sample containers 12 may also be included.

[0015] When dispensing a sample, the control unit first controls the horizontal drive unit of the sample dispensing mechanism 2 to drive the sample dispensing probe 10 horizontally to a position above the sample container 12. Next, the control unit controls the up / down drive unit of the sample dispensing mechanism 2 to drive the sample dispensing probe 10 vertically downward to pierce the stopper 13 of the sample container 12. Thereafter, the control unit operates the syringe with the sample dispensing probe 10 immersed in the sample 11, thereby aspirating a predetermined amount of sample 11 into the sample dispensing probe 10.

[0016] When the suction of the sample 11 is completed, the control unit controls the vertical drive unit to raise the sample dispensing probe 10, and then controls the horizontal drive unit to move the sample dispensing probe 10 to a position above the reaction vessel 4. Next, the control unit controls the vertical drive unit of the sample dispensing mechanism 2 to lower the sample dispensing probe 10, and then operates the syringe to dispense a predetermined amount of sample 11 from the sample dispensing probe 10 into the reaction vessel 4.

[0017] When the control unit moves the sample dispensing probe 10 to each of the aforementioned positions and stops it, it uses a control method of stopping the drive unit based on a detection signal from a predetermined sensor, or a control method of giving the drive unit a specified amount of movement from the reference position to the stop position. In addition, the tip of the sample dispensing probe 10 has a sharp shape so that it can penetrate the stopper 13.

[0018] Furthermore, each time the control unit finishes aspirating and dispensing one sample, it moves the sample dispensing probe 10 to the washing tank 15 and dispenses washing water from the washing tank 15 onto the sample dispensing probe 10, thereby washing the sample dispensing probe 10. This prevents the sample from being mixed with the previous sample when another sample is subsequently dispensed using the same sample dispensing probe 10.

[0019] FIG. 3 is a diagram illustrating a mechanism for detecting contact of the tip of the sample dispensing probe. As shown in FIG. 3, the sample dispensing mechanism 2 of this embodiment further includes a stopper 21, a detection plate 23, a contact detection sensor 20, and a spring 22. The stopper 21 prevents the sample dispensing probe 10 from moving downward beyond a specified range. The detection plate 23 is fixed to the sample dispensing probe 10 above the stopper 21 via a connection portion 24. The contact detection sensor 20 detects contact of the tip of the sample dispensing probe 10 when the detection plate 23 enters its light irradiation range (detection range), thereby blocking light. The spring 22 presses the connection portion 24, which is integral with the sample dispensing probe 10, downward.

[0020] When no object is in contact with the tip of the sample dispensing probe 10, the connecting part 24 is pressed against the stopper 21 by the pressing force of the spring 22, as shown on the left side of Fig. 3, and is in a positioned state, and the detection plate 23 is not within the detection range of the contact detection sensor 20. However, if an object 25 comes into contact with the tip of the sample dispensing probe 10 while it is descending, as shown on the right side of Fig. 3, the connecting part 24 moves upward against the pressing force of the spring 22, and the detection plate 23 also moves upward and enters the detection range of the contact detection sensor 20.

[0021] When the contact detection sensor 20 detects the entry of the detection plate 23, the control unit controls the vertical drive unit to stop the downward movement of the sample dispensing probe 10. As a result, even if the sample dispensing probe 10 comes into contact with the object 25 during its descent, the sample dispensing probe 10 safely stops without damaging the device. When the tip of the sample dispensing probe 10 leaves the object 25, the pressing force of the spring 22 presses the connection part 24 against the stopper 21, returning the sample dispensing probe 10 to its positioned state.

[0022] Even if the object 25 is a reaction vessel 4 or a washing tank 15, contact is detected by the same behavior. However, when the specimen dispensing probe 10 penetrates the stopper 13 of the specimen vessel 12 to aspirate the specimen, it is desirable to control the specimen dispensing probe 10 so that the downward movement of the specimen dispensing probe 10 is not stopped even if the detection plate 23 enters the detection range of the contact detection sensor 20.

[0023] FIG. 4 shows the positional relationship between a new sample dispensing probe, a sample dispensing probe with a worn tip, and a reference surface. As shown in FIG. 4 , the positions of the probe tips of a new sample dispensing probe (hereinafter referred to as the pre-used probe 10a) and a sample dispensing probe with a worn tip (hereinafter referred to as the used probe 10b) differ when they are at the origin height. Here, the probe origin height refers to the probe height when the motor constituting the vertical drive unit of the sample dispensing mechanism 2 is at the origin position. As shown in FIG. 4 , the positions of the detection plate 23 and other components of the used probe 10b are the same as those of the pre-used probe 10a, but the position of the tip of the used probe 10b is higher than that of the pre-used probe 10a. This is because the length of the probe shortens when the probe is used repeatedly for dispensing, particularly when the probe repeatedly penetrates the stopper 13. Therefore, when the probe is lowered from the origin height to contact with the reference surface 31, the descent amount Y of the used probe 10b is longer than the reference descent amount X of the pre-used probe 10a.

[0024] [Method for measuring the length of a probe before use (reference length)] Figure 5 is a flowchart showing the operation for measuring the length of a probe before use, and Figure 6 is a time chart showing the operation for measuring the probe length. First, a user or other person attaches a new sample dispensing probe 10, that is, a pre-use probe 10a, to the sample dispensing mechanism 2 of the automatic analyzer. Next, the user performs a predetermined operation using the input unit to instruct the start of the operation for measuring the reference length (reference descent amount).

[0025] Then, the control unit controls the horizontal drive unit of the sample dispensing mechanism 2 to move the pre-use probe 10a to a home position at a specified horizontal position (step S101). When the pre-use probe 10a is at the home position, its vertical position is the same as the above-mentioned origin height.

[0026] Next, the control unit controls the horizontal drive unit of the sample dispensing mechanism 2 to move the pre-use probe 10a above a predetermined reference plane 31 (see FIG. 4 ) that forms part of the automatic analyzer (step S102). This movement is, for example, a translation to the right or a rotational movement in the clockwise direction, and corresponds to horizontal movement A in FIG.

[0027] The control unit then controls the vertical drive unit of the sample dispensing mechanism 2 to lower the pre-use probe 10a, and stops the lowering of the pre-use probe 10a when the contact detection sensor 20 detects contact with the reference surface 31 (step S103). At this time, the control unit calculates the amount of descent from the origin height based on the operation log of the vertical drive unit, and stores the calculation result in the memory unit as the reference descent amount X (step S104). Note that when the tip of the pre-use probe 10a contacts the reference surface 31, the detection plate 23 enters the light irradiation range of the contact detection sensor 20 and becomes dark, so that contact is detected as shown in FIG.

[0028] The control unit then controls the vertical drive unit to raise the probe 10a before use to the origin height. Furthermore, the control unit controls the horizontal drive unit to move the probe 10a before use to the home position. This movement is, for example, a translation to the left or a rotational movement in the left direction, which corresponds to horizontal movement B in FIG. 6 .

[0029] Note that if the reference surface 31 is a flat surface that forms, for example, the washing tank 15, there is an advantage that even if a sample adheres to the reference surface 31 due to contact with the sample dispensing probe 10, the sample can be washed away by the washing tank 15. However, as long as it is a flat surface that forms part of the device and whose positional relationship with the device (particularly height) does not change, rather than a surface that may cause variations in its positional relationship with the device, such as the bottom surface of a container, the reference surface 31 may also be a portion other than the washing tank 15. Furthermore, the reference surface 31 is not limited to a portion already installed in the device, but may be formed by newly providing a metal portion that is difficult to deform within the movement trajectory of the sample dispensing probe 10.

[0030] 7 is a flowchart showing the operation of checking the probe status based on the change in the probe length. When the operation of checking the probe status is started at a predetermined timing described later, the length (amount of descent) of the used probe 10b, which has worn down due to repeated dispensing, is measured.

[0031] First, the control unit controls the horizontal drive unit of the sample dispensing mechanism 2 to move the used probe 10b to a home position, which is a specified horizontal position (step S201). Next, the control unit controls the horizontal drive unit of the sample dispensing mechanism 2 to move the used probe 10b above the reference surface 31 (step S202). Thereafter, the control unit controls the vertical drive unit of the sample dispensing mechanism 2 to lower the used probe 10b, and when the contact detection sensor 20 detects contact with the reference surface 31, the control unit stops the lowering of the used probe 10b (step S203). At this time, the control unit calculates the amount of lowering from the origin height based on the operation log of the vertical drive unit and stores the calculated amount of lowering Y in the memory (step S204).

[0032] Next, the control unit calculates the amount of change in the amount of descent α (see FIG. 4) from the difference between the amount of descent Y measured in step S204 and the reference amount of descent X measured in FIG. 5 (step S205). In reality, there is a certain detection delay between when the sample dispensing probe 10 contacts the reference surface 31 and when the contact detection sensor 20 detects the entry of the detection plate 23. However, this detection delay is generally constant regardless of the amount of change in the length of the sample dispensing probe 10 and does not affect the measurement of the amount of descent X and the reference amount of descent Y. Therefore, the detection delay is not taken into account in this embodiment.

[0033] As the sample dispensing probe 10 wears due to repeated use, the change in the amount of descent α gradually increases, eventually requiring replacement of the sample dispensing probe 10. Therefore, the control unit outputs a warning alarm (first alarm) at a stage where dispensing is not possible without replacing the sample dispensing probe 10. Furthermore, the control unit also outputs a caution alarm (second alarm) when the time to replace the sample dispensing probe 10 is approaching. To determine whether or not to output these two types of alarms, two types of thresholds are stored in advance in the memory unit. While this embodiment will be described using two types of alarms and two types of thresholds as examples, the number of types of alarms and thresholds may be one or three or more.

[0034] The first threshold A is a threshold for determining whether a warning alarm needs to be output, and when the change amount α reaches this threshold, it is determined that the necessary dispensing accuracy cannot be ensured and that the probe 10b needs to be replaced after use. The second threshold B is a threshold for determining whether a caution alarm needs to be output, and when the change amount α reaches this threshold, it is determined that the time to replace the probe 10b after use is approaching. Note that the second threshold B is smaller than the first threshold A, and these thresholds are stored in the memory unit.

[0035] The control unit compares the amount of change α calculated in step S205 with a first threshold A and a second threshold B (step S206). If the amount of change α is equal to or greater than the first threshold A, the control unit outputs a warning alarm (step S207) and stops the dispensing operation (step S208). In step S208, if the dispensing operation has not yet started for a series of samples, the control unit may prevent subsequent dispensing operations. If the dispensing operation is in the middle of a series of samples, the control unit may prevent dispensing operations after the dispensing of the remaining samples has been completed.

[0036] On the other hand, if it is determined in step S206 that the amount of change α is less than the first threshold value and equal to or greater than the second threshold value B, the control unit outputs a caution alarm (step S209). In this case, dispensing accuracy can be guaranteed, so the dispensing operation starts and continues (step S210), and ends when all requested samples have been dispensed (step S211).

[0037] Furthermore, if in step S206 it is determined that the change amount α is less than the second threshold value B, the control unit starts and continues the dispensing operation without outputting an alarm (step S210), and ends the dispensing operation when all the samples have been dispensed (step S211).

[0038] In this way, by determining the condition of the probe based on the change in the length of the probe, it is possible to determine the appropriate time to replace the probe. It is also possible to determine abnormalities such as bent or broken probes.

[0039] [Method for correcting probe lowering amount] When the sample dispensing probe 10 dispenses the aspirated sample into the reaction vessel 4, the control unit applies a specified operation amount (e.g., number of pulses) to the vertical drive unit of the sample dispensing mechanism 2 to lower the sample dispensing probe 10 a specified distance from the origin height. Figure 8 is a diagram showing the positional relationship between the pre-use probe and the post-use probe and the reaction vessel when they are lowered a specified amount from the origin height.

[0040] As shown in Figure 8, the probe tip positions of the pre-use probe 10a and the post-use probe 10b are different even when the probes are lowered the same distance from the origin height. That is, Figure 8 shows that the tip of the pre-use probe 10a is in contact with the bottom of the reaction vessel 4, while the tip of the post-use probe 10b is spaced from the bottom of the reaction vessel 4 by a change amount α. To maintain dispensing accuracy, the sample dispensing probe 10 typically dispenses sample while in contact with the bottom of the reaction vessel 4. However, repeated use shortens the sample dispensing probe 10, and if the sample is dispensed while spaced from the bottom of the sample vessel 12, dispensing accuracy may decrease. Therefore, in this embodiment, the probe descent amount during the sample dispensing operation is corrected based on the difference between the probe descent amount Y during the status confirmation operation described above with reference to Figure 7 and the reference descent amount X.

[0041] FIG. 9 is a schematic diagram illustrating the concept of correcting the probe descent amount. When dispensing a sample using the pre-used probe 10a, the control unit applies a predetermined amount of movement to the vertical drive unit of the sample dispensing mechanism 2 to lower the pre-used probe 10a by a descent amount X1 from the origin height 37. On the other hand, when dispensing a sample using the used probe 10b, the control unit applies a predetermined amount of movement to the vertical drive unit of the sample dispensing mechanism 2 to lower the used probe 10b by a corrected descent amount Y1 from the origin height. Here, the corrected descent amount Y1 is calculated by adding the change amount α calculated in the above-mentioned status confirmation operation to the reference pre-correction descent amount X1. In this way, by correcting the probe descent amount according to the degree of wear, i.e., the length of the probe, the probe tip can be reliably brought into contact with the bottom surface of the sample container 12, thereby ensuring dispensing accuracy. Note that, until the change amount α reaches the first threshold value A, dispensing accuracy can be ensured by correcting the probe descent amount, but once the change amount reaches the first threshold value A, dispensing accuracy cannot be ensured by correcting the probe descent amount, and the probe must be replaced.

[0042] [Method of predicting probe replacement time] Fig. 10 is a graph showing an example of the relationship between the amount of change in the amount of probe descent and the number of dispensings. The amount of change α in the amount of probe descent is calculated each time the state of the probe 10b is checked after use and stored in the memory unit. The multiple points 51 plotted in Fig. 10 show the progress of the amount of change α calculated in each checking operation (vertical axis) and the progress of the cumulative number of dispensings at the time of calculation (horizontal axis). The control unit generates an approximation curve 52 connecting these multiple points 51 and the origin, and by calculating the slope of the approximation curve 52, predicts the number of dispensings N when the amount of change α reaches the first threshold A. Ａ and the number of dispensings N when the second threshold B is reached Ｂ The control unit outputs the prediction result to inform the user of the approximate time to replace the probe, and can prompt the user to prepare for probe replacement. Note that the prediction is not limited to the number of dispensings until each threshold is reached. For example, the control unit may predict the number of days until each threshold is reached by creating an approximation curve for the relationship between the amount of change α and the number of days.

[0043] [Probe Status Confirmation Screen] FIG. 11 shows an example of a probe status confirmation screen. For example, when a user performs a predetermined operation using the input unit on a maintenance menu for the automated analyzer, the control unit reads the history of status confirmation operations stored in the memory unit and displays a status confirmation screen (maintenance history) such as that shown in FIG. 11 on the output unit. The confirmation operation date and time display field 41 displays the date and time when the probe status confirmation operation was performed. The length change amount display field 42 displays the change amount α calculated by the status confirmation operation. The displayed change amount α may be the number of pulses applied to the vertical drive unit, but it is easier for the user to understand if it is converted into length. Furthermore, the degree of shortening, assuming the length of the probe 10a before use as 100, can be displayed as a percentage or in a graph. The dispensing count display field 43 displays the cumulative number of dispensings at the time the status confirmation operation was performed. Note that if the change amount α begins to decrease (becomes zero), this indicates that the probe has been replaced, and the cumulative number of dispensings may be automatically reset to zero. The first threshold A display field 44 displays the number of remaining dispenses until the amount of change α reaches the first threshold A, and the second threshold B display field 45 displays the number of remaining dispenses until the amount of change α reaches the second threshold B. The remaining number of dispenses displayed in these fields is predicted by the method described above with reference to FIG. 10.

[0044] It is desirable that the probe status check operation be performed periodically, and for example, it may be incorporated into the preparatory operation performed at the start of an analysis operation so that it is performed automatically with each analysis operation. Also, as shown in Figure 11, a check operation execution button 46 may be provided on the status check screen so that the probe status check operation is immediately performed when this button is operated.

[0045] [Probe Length Measurement Setting Screen] FIG. 12 illustrates an example of a probe length setting screen. On the screen shown in FIG. 12, the user can appropriately specify the timing for performing the probe status check operation. For example, the user can specify that the probe status check operation be performed before the start of a series of sample dispensing operations, or after the start of a series of sample dispensing operations. Furthermore, since the status check operation in this embodiment is performed in one cycle, it can be performed at any available cycle, even during a series of sample dispensing operations. Furthermore, a predetermined number of dispensing operations may be specified in advance, and the probe status check operation may be performed when the cumulative number of dispensing operations reaches the specified number. If the specified number (e.g., 500) is reached during a series of sample dispensing operations, the probe status check operation may be performed when the remaining sample dispensing operations are completed (e.g., 520).

[0046] The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above-described embodiment, a sensor that detects contact of the probe tip by the penetration of the detection plate 23 is used as the contact detection sensor 20, but instead of this sensor, a sensor that detects contact of the probe tip by detecting changes in capacitance or pressure may be used. Furthermore, in the above-described embodiment, the sample dispensing probe 10 that aspirates and dispenses a sample is described, but the present invention can also be applied to a dispensing probe that aspirates and dispenses other liquids, such as reagents and detergents.

[0047] Furthermore, although the above-described embodiment has been described with reference to an example of an automatic analyzer equipped with an analysis unit that analyzes a mixture of a sample and a reagent, the present invention can also be applied to a dispensing device that does not have an analysis unit and that only dispenses samples. For example, the present invention can be applied to a sample transport device that dispenses a sample from a sample container that has been inserted into a sample insertion unit and closed with a stopper into another container, and transports containers that contain the subdivided sub-samples.

[0048] 1...computer, 2...sample dispensing mechanism, 3...reagent dispensing mechanism, 4...reaction vessel, 5...reagent refrigerator, 10...sample dispensing probe, 10a...pre-use probe, 10b...post-use probe, 11...sample, 12...sample vessel, 13...stopper, 14...sample rack, 15...washing tank, 20...contact detection sensor, 21...stopper, 22...spring, 23...detection plate, 24...connection part, 25...object, 37...origin height, 51...point, 52...approximation curve, 41...confirmation operation date and time display column, 42...length change amount display column, 43...dispensing count display column, 44...first threshold A display column, 45...second threshold B display column, 46...confirmation operation execution button.

Claims

1. A probe for sucking and discharging a liquid, a sensor for detecting contact at the tip of the probe, a drive unit for driving the probe in the vertical direction, and a control unit for controlling the drive unit, in a dispensing device, wherein the control unit periodically performs a confirmation operation of a change in the length of the probe, and in the confirmation operation, the probe is lowered by the drive unit until contact with a predetermined reference plane forming part of the dispensing device is detected. A dispensing device characterized by this.

2. In the dispensing device according to Claim 1, wherein the control unit outputs an alarm when a difference between the amount of descent of the probe in the confirmation operation and a reference amount of descent is equal to or greater than a predetermined threshold value. A dispensing device characterized by this.

3. In the dispensing device according to Claim 2, the control unit when the difference is equal to or greater than a first threshold value, outputs a first alarm and does not perform the liquid discharge operation, and when the difference is equal to or greater than a second threshold value smaller than the first threshold value, outputs a second alarm different from the first alarm and performs the liquid discharge operation. A dispensing device characterized by this.

4. In the dispensing device according to Claim 2, wherein the control unit predicts the number of dispensing times until the difference reaches the threshold value based on the relationship between the transition of the number of dispensing times by the probe and the transition of the difference. A dispensing device characterized by this.

5. In the dispensing device according to Claim 1, wherein the control unit corrects the amount of descent of the probe in the liquid discharge operation based on the difference between the amount of descent of the probe in the confirmation operation and a reference amount of descent. A dispensing device characterized by this.

6. In the dispensing device according to Claim 5, when the difference becomes equal to or greater than a first threshold value, a first alarm is output and the liquid discharge operation is not performed. A dispensing device characterized by this.

7. In the dispensing device according to Claim 1, wherein the control unit performs the confirmation operation at a preset timing. A dispensing device characterized by this.

8. In the dispensing device according to Claim 1, wherein the probe penetrates a stopper for closing a container and sucks the liquid in the container. A dispensing device characterized by this.

9. A probe for sucking and discharging a liquid, a sensor for detecting contact at the tip of the probe, a cleaning tank for cleaning the probe, a drive unit for driving the probe in the vertical direction, In a dispensing device including a control unit that controls the drive unit, the control unit performs an operation of checking the change in the length of the probe by lowering the probe by the drive unit until contact with a predetermined reference surface that forms part of the dispensing device is detected. The dispensing device is characterized in that the reference surface is a plane forming the cleaning tank.

10. A method for checking the state of a probe of a dispensing device that dispenses a liquid, wherein an operation of checking the change in the length of the probe is periodically performed, and in the checking operation, the probe is lowered until contact with a predetermined reference surface that forms part of the dispensing device is detected.