JPH04286961A - Dispenser - Google Patents

Abstract

PURPOSE:To compensate a position of a moving body of an automatic dispenser and to achieve a stable operation. CONSTITUTION:A stable operation can be achieved by maintaining a positional deviation of a moving body during dispensing operation within an allowable range. Zero-point positioning of a plunger drive mechanism 6 and an up/down traveling mechanism 7 is performed for each specified number of operations. A position detector of the plunger drive mechanism 6 and the up/down drive mechanism 7 is provided. Then, when a traveling error of the plunger or a tip portion exceeds a specified value by the position detector, zero-point positioning of the plunger drive mechanism 6 or the up/down traveling mechanism 7 is performed, thus enabling the position to be compensated for.

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 quantifying a liquid, which is used in an automatic chemical analyzer or a reaction purification device for biological samples such as nucleic acids.

0002

[Prior Art] As a dispensing device used in automatic chemical analyzers and reaction purification devices for biological samples such as nucleic acids, JP-A-1-1
As described in Japanese Patent Application Laid-open No. 23154 and Japanese Patent Application Laid-open No. 106341/1982, there are devices that suck and discharge liquid by moving a plunger.

FIG. 2 is a block diagram showing a conventional dispensing device using a plunger. This device includes a tip 2 for attaching and detaching a dispensing tip 1, a body 3 located above the tip 2, an atmosphere communication hole 4 penetrating the tip 2 and the body 3, and a plunger that moves within the atmosphere communication hole 4. 5. Pulse motor 6-1, coupling 6-2, ball screw 6-3, plunger holding member 6-4, vertical slider 6-5 of plunger 5, bearing member 6-6, plunger origin position that determines the plunger origin position A plunger drive mechanism 6 consisting of a detector 6-7,
Pulse motor 7-1 of the vertical moving part, coupling 7-2 of the vertical moving part, ball screw 7-3 of the vertical moving part, plunger drive mechanism holding member 7-4, vertical slider 7-5 of the plunger drive mechanism 6, bearing member 7-6, a vertical movement mechanism 7 for vertically moving the portion from the tip section 2 to the plunger drive mechanism 6, which consists of a tip section origin position detector 7-7 that determines the origin position of the tip section 2, a dispensing tip 1, A container transport mechanism 11 that transports a container 9 containing a liquid 8 and a container 10 into which the liquid is to be dispensed, a controller 12 that controls operations of the plunger drive mechanism 6, the vertical movement mechanism 7, and the container transport mechanism 11, and a plunger drive. The dispensing tip push-out member 13 slides on the outside of the body 3 in conjunction with the mechanism 6, and comes into contact with the attached dispensing tip 1, and the dispensing tip push-out member 13 slides to dispense from the tip 2. It consists of a tip removal member 14 that pushes and removes the tip 1 for use. Note that the origin position detector is composed of a phototransistor and a light shielding plate.

[0004] This dispensing device transfers liquid to another container by the following operation. The container transport mechanism 11 positions the dispensing tip 1 (hereinafter referred to as the tip 1) below the tip 2, and the vertical movement mechanism 7 lowers the tip 2.
Attach chip 1 by pressing it onto chip 1. Next, the container 9 is positioned below the chip 1 by the container transport mechanism 11, and is lowered by the vertical movement mechanism 7 until the chip 1 is immersed in the liquid 8, and then the plunger 5 is raised by a predetermined amount by the plunger drive mechanism 6. Aspirate liquid 8 into chip 1. Next, the chip 1 is raised by the vertical movement mechanism 7, another container 10 to which the liquid 8 is to be transferred is positioned below the chip 1 by the container transport mechanism 11, the chip 1 is lowered by the vertical movement mechanism 7, and the chip 1 is lowered by the vertical movement mechanism 7. is inserted into the container 10, the plunger 5 is lowered by a predetermined amount by the plunger drive mechanism 6, and the liquid 8 is discharged. The amount of plunger movement during ejection is set to be a certain amount larger than the amount of plunger movement during suction to prevent the liquid 8 from remaining in the tip 1. Next, the container transport mechanism 11 transports the discard port (not shown) for discarding the chip 1 to the lower part of the dispensing device, where the plunger drive mechanism 6 is driven to eject the chip removal member 14 via the chip push-out member 13. Push downward and remove chip 1.

Next, the control method of the dispensing device will be explained. The driving elements of the plunger drive mechanism 6 and the vertical movement mechanism 7 include:
Pulse motors 6-1 and 7-1 are used, and the plunger drive mechanism 6 and vertical movement mechanism 7 are positioned at each origin using a plunger origin position detector 6-7 and a tip origin position detector 7-7. Then, a pulse signal corresponding to the moving distance is applied from the controller 12 to these pulse motors, and the moving body is moved by a relative distance from the origin position.

[0006]

[Problems to be Solved by the Invention] When attaching the tip 1, the tip 2 is strongly pressed against the tip 1 in order to maintain airtightness between the tip 2 and the tip 1. Therefore, a large load is placed on the vertical movement mechanism 7 that drives the position of the tip portion 2. In addition, even when the tip 1 is removed by the tip extrusion member 13 that slides in conjunction with the drive of the plunger drive mechanism 6, the tip 1 is firmly attached to the tip 2 as described above, so the plunger drive mechanism 6 It also puts a heavy burden on it. The operation of attaching and detaching the chip 1 in this way involves the vertical movement mechanism 7 and the plunger drive mechanism 6.
A load greater than that required to move the moving object is placed on the vehicle. At this time, slipping occurs in the coupling 7-2 that connects the vertically moving body including the vertically moving mechanism 7 and the plunger drive mechanism 6, and in the coupling 6-2 that connects the plunger driving mechanism 6 and the plunger 5. As a result, the amount of movement when the moving part is raised is larger than the amount of movement when it is lowered due to the error caused by slipping, and if the dispensing operation continues in this state, the error will accumulate and the vertical movement mechanism 7 When the tip 2 is not lowered to the attachment position of the tip 1 and the tip 1 cannot be attached, or when the tip is lowered into the container 9 containing the liquid 8, the tip 1 is immersed in the surface of the liquid 8. When discarding the tip 1 in the plunger drive mechanism 6, the plunger 5 does not descend to the position where the tip 1 is removed even if the tip pushing member 13 is pushed, making it impossible to remove the tip 1. Ta.

An object of the present invention is to solve the problem of unstable dispensing operations due to slipping of couplings, which prevents the positional relationships of moving bodies from being maintained, and to provide means for enabling reliable, high-speed automatic dispensing. Our goal is to provide the following.

[0008]

[Means for Solving the Problems] Dispensing operations are frequently used in chemical analysis and reaction purification processes of biological samples such as nucleic acids. Therefore, in order to realize high-speed automatic processing, it is necessary to perform the dispensing operation in as short a time as possible. Therefore, in this dispensing device, a small pulse motor is used for each drive element for the plunger and vertical movement, and the pulse motor is positioned at the origin before operation, and then a pulse signal corresponding to the moving distance is given from the controller 12 to generate a pulse. A simple and quick control method is adopted to drive the motor. Another method is a more precise positioning method in which a detector is installed at the stop position of the moving part, and when the moving body reaches the stop position, the drive mechanism receives a stop signal from the detector and stops the moving body. However, when the drive motor is stopped by a stop signal, the drive motor must be driven at low speed, which slows down the dispensing operation and complicates the control, making it impossible to perform high-speed dispensing. Therefore, by setting the origin position in advance using a pulse motor,
The optimal method is to provide a pulse motor with a pulse signal corresponding to the distance traveled.

[0009] In this method, stable dispensing operation is achieved by keeping the positional displacement of the movable body within a permissible range during the dispensing operation. The method is described below.

1) The origin position of the plunger drive mechanism and the vertical movement mechanism is determined every predetermined number of operations.

2) A position detector is provided for the plunger drive mechanism and the vertical movement mechanism, and when the position detector detects that the movement error of the plunger or the tip has become larger than a predetermined value, the plunger drive mechanism or The origin position of the vertical movement mechanism is determined and the position is corrected.

0012

[Operation] The operation of the dispensing device according to the present invention will be explained.

1) When the origin position is performed every predetermined number of dispensing operations, the error that occurs in the origin position of the movable body can be corrected by positioning the origin within the allowable range that prevents dispensing errors from occurring. It is corrected by being positioned at the origin position, and the position of the moving body can be kept constant, thereby stabilizing the dispensing operation.

2) When a position detector is installed at a predetermined position, when a predetermined pulse signal is applied to each pulse motor of the plunger drive mechanism 6 and vertical movement mechanism 7 to move the movable body, the movable body detects the position detector. If the movement error becomes larger than the predetermined value without reaching , the current dispensing operation is performed, and then the origin position of the pulse motor in question is determined. This corrects movement errors and enables stable dispensing operations. In either method 1) or 2), a stable dispensing operation is possible without reducing the dispensing operation speed more than necessary.

[0015]

Embodiment Embodiment 1 will be explained using the flowchart of FIG. In this embodiment, before performing the dispensing operation, the plunger 5 and the tip 2 are set at the origin position using the origin position detectors 6-7 and 7-7. Next, a dispensing operation is performed. At this time, the number i of dispensing operations is accumulated. Each time a dispensing operation is completed, this cumulative number of times i is compared with the set value n, and when i is less than n, the next dispensing operation is continued, but when i exceeds n, each mechanism section 6 and 7 is The origin position is determined and the cumulative number of times i is reset to zero. This set value n is given so that movement errors due to coupling slippage do not affect the dispensing operation, so that a stable dispensing operation is always guaranteed.

Next, a second embodiment will be explained using the configuration diagram of the main part of the embodiment shown in FIG. 3 and the flowchart shown in FIG. This embodiment has basically the same structure as that shown in FIG. 7-8 and a tip end stop position detector 7-9. These position detectors, for example, are composed of a phototransistor and a light shielding plate, similar to the origin position detector,
Stop position detectors 6-9 and 7-9 are installed at locations where it is possible to detect that the plunger 5 and the tip 2, which are moving objects, have descended and stopped at a predetermined stop position, and the moving object is placed between the vicinity of the stop position and the origin. Position detectors 6-8 and 7-8 are provided at locations where it can be detected that the robot is moving up and down. The tip stop position detector 7-9 is installed with a little margin relative to the position that the tip must reach. That is, even when it does not produce an output, when operated in a predetermined sequence, the tip is placed in a position approximately reaching the position it is required to reach.

The operation of this embodiment will be described using the vertical movement mechanism 7 as an example.

During the operation of lowering the tip 2, when the light shielding plate passes the phototransistor of the tip position detector 7-8, it is recognized that the tip 2 is in the lowering operation. Next, when the tip 2 reaches a predetermined stop position, the tip stop position detector 7-9 detects this and recognizes that the tip 2 stops at the predetermined position and is operating normally. After attaching the tip 1, the tip 2 rises and returns to the tip position detector 7.
-8, it is recognized that the tip 2 is in the process of rising, and the series of lowering and rising operations of the tip 2 ends. When coupling slippage errors accumulate and an error occurs in the origin position of the tip 2, the situation is the same as in a normal case until the tip 2 is detected by the tip position detector 7-8 during the downward movement. However, since the origin position of the tip part 2 is shifted upward, the tip part 2 cannot reach the predetermined stop position, and the tip part stop position detector 7-9
cannot detect that the tip portion 2 has stopped. At this time, the current dispensing operation is performed as is. In the next sequence after the end of the dispensing operation, the tip stop position detector 7-9 will not be able to detect that the tip 2 has stopped again, but at this time, the origin position of the tip 2 will be determined and the position will be corrected. conduct. The operation of the plunger drive mechanism 6 is also the above-mentioned vertical movement mechanism 7.
The operation is the same as in the above, and the same is true when the plunger drive mechanism 6 and the vertical movement mechanism 7 are operated simultaneously. In this method as well, stable dispensing operation can be guaranteed since the cumulative error of coupling slippage can be automatically corrected when it becomes large.

[0019]

[Effects of the Invention] As explained above, according to the present invention, in this dispensing device, the origin position of each moving body during dispensing is maintained within a predetermined range, and highly reliable dispensing operation can be performed at high speed. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional dispensing device.

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 is a flowchart showing a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Dispensing tip, 2...Tip part, 3...Body part, 4...Air communication hole, 5...Plunger, 6...Plunger drive mechanism, 6
-1...Pulse motor, 6-2...Coupling, 6-3...
Ball screw, 6-4... Plunger holding member, 6-5... Vertical slider, 6-6... Bearing member, 6-7... Plunger origin position detector, 6-8... Plunger position detector, 6-9
...Plunger stop position detector, 7...Vertical movement mechanism, 7-
1...Pulse motor, 7-2...Coupling, 7-3...Ball screw, 7-4...Plunger drive mechanism holding member, 7-
5... Vertical slider, 7-6... Bearing member, 7-7... Tip origin position detector, 7-8... Tip position detector, 7-9...
Tip stop position detector, 8...liquid, 9...container (reagent side)
, 10... Container (reaction side), 11... Container transport mechanism, 12...
Controller, 13...Dispensing tip extrusion member, 14...
Chip removal member.

Claims (2)

[Claims] 1. A plunger drive mechanism that drives a pulse motor to move a plunger that holds a tip portion where liquid is sucked and discharged, a moving mechanism that moves the vertical position of the plunger drive mechanism by driving a pulse motor, and a container. In a dispensing machine consisting of a transport mechanism and a controller that controls the relative positions of these mechanisms in a predetermined sequence operation, the origin position of the plunger drive mechanism and vertical movement mechanism is determined every predetermined number of sequence operations. A dispensing device characterized in that it is configured as follows. 2. A plunger drive mechanism that drives a pulse motor to move a plunger that holds a tip portion where liquid is sucked and discharged, a moving mechanism that moves the vertical position of the plunger drive mechanism by driving a pulse motor, and a container. A dispensing machine comprising a transport mechanism and a controller that controls the relative positions of these mechanisms in a predetermined sequence of operations is provided with a position detector that detects when the tip reaches a predetermined stop position. Even when the position detector does not produce an output in the steps of a predetermined sequence, the predetermined sequence operation continues, and when the position detector does not produce an output again in the steps of the predetermined sequence, the origin position of the plunger drive mechanism and vertical movement mechanism is determined. A dispensing device characterized by being configured to perform the following.