Liquid ejection device, liquid ejection control method, and filling method

Abstract

[Problem] To provide: a liquid discharge device that comprises a pump using a tube and is capable of highly accurate liquid discharge; a liquid discharge control method; and a filling method. [Solution] This liquid discharge device comprises a liquid transfer pump, a first flow path, a second flow path, and a flow path switching part. The liquid transfer pump includes: a flexible tube through which liquid can circulate; a pressing part which presses the flexible tube from the outer peripheral surface side to feed the liquid from one end of the flexible tube to the other end; and a drive unit which rotationally drives the pressing part. The first flow path and the second flow path, which differ from each other, are flow paths from which the liquid transferred from the liquid transfer pump flows out. The flow path switching part is controlled such that a flow path from which the liquid for discharge transferred from the liquid transfer pump flows out is defined as the first flow path, and a flow path from which the liquid transferred from the liquid transfer pump flows out in a period from after the liquid for discharge is transferred to until the drive unit moves to a position at a flow out start time of the liquid for discharge is defined as the second flow path.

Description

[Technical Field]

[0001] The present technology relates to a liquid ejection device, a liquid ejection control method, and a filling method. [Background technology]

[0002] Volumetric metering pumps capable of high-precision dispensing, such as plunger pumps, ensure this precision by repeatedly measuring and dispensing volumes using syringes and plungers manufactured with high machining precision. However, such processed products are expensive and require long delivery times, making it unrealistic to dispose of all liquid-contacting parts. Therefore, when dispensing different liquids using the same pump, cleaning and sterilization processes are necessary for setup changes, which poses issues such as operability, safety, and the risk of contamination.

[0003] There are also tube pumps that use tubes as pumps with disposable liquid-contacting parts (see, for example, Patent Document 1). Tube pumps use a system in which an elastic liquid-transporting tube is squeezed with parts such as rollers to push out the liquid inside the tube. Compared to the volumetric pumps mentioned above, tube pumps have poor liquid-transporting and dispensing accuracy, and are not suitable for applications that require high repeatability. However, disposable liquid-contacting parts are required in many industries, including the medical, food, and manufacturing industries. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-181550 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, a liquid ejection device equipped with a pump using a tube has a problem in that it is difficult to eject liquid with high precision.

[0006] In view of the above circumstances, an object of the present technology is to provide a liquid discharge device including a pump using a tube, a liquid discharge control method, and a filling method that enable highly accurate liquid discharge.

Means for Solving the Problems

[0007] To achieve the above object, a liquid discharge device according to one embodiment of the present technology includes a liquid transfer pump, a first flow path, a second flow path, and a flow path switching unit. The liquid transfer pump includes a flexible tube through which the liquid supplied from a liquid storage unit for storing the liquid can flow, a pressing unit that presses the flexible tube from the outer peripheral surface side to send the liquid from one end of the flexible tube to the other end, and a driving unit that rotationally drives the pressing unit. The first flow path is a flow path through which the liquid transferred from the liquid transfer pump flows out. The second flow path is a flow path different from the first flow path through which the liquid transferred from the liquid transfer pump flows out. The flow path switching unit is a flow path switching unit that sets the flow path through which the liquid transferred from the liquid transfer pump flows out to be the first flow path or the second flow path. The flow path through which the liquid for discharge transferred from the liquid transfer pump flows out is set to be the first flow path, and after the liquid for discharge is transferred, until the driving unit moves to the position at the start of the outflow of the liquid for discharge, the flow path through which the liquid transferred from the liquid transfer pump flows out is controlled to be the second flow path.

[0008] According to such a configuration, since the discharge is performed such that the position of the flexible tube pressed by the pressing unit is always the same position each time, it is possible to accurately control the discharge amount each time.

[0009] The driving unit of the liquid transfer pump is driven based on a pulse signal. When the number of pulses of the discharge pulse signal for transferring the liquid for discharge is set to m (m > 0), and the number of pulses of the pulse signal required for one rotation of the driving unit is set to n (n > 0). When n < m. The above flow path switching unit designates the flow path through which the liquid transferred from the above liquid transfer pump driven based on the above discharge pulse signal flows as the above first flow path. After the above discharge liquid has been transferred, it is controlled such that the flow path through which the liquid transferred from the above liquid transfer pump driven based on a pulse signal having a pulse number b satisfying m = an + b (a is an integer of 1 or more, b > 0, n > b) flows is the above second flow path. In the case where n > m, the above flow path switching unit may be controlled such that the flow path through which the liquid transferred from the above liquid transfer pump driven based on the above discharge pulse signal flows is the above first flow path, and after the above discharge liquid has been transferred, the flow path through which the liquid transferred from the above liquid transfer pump driven based on a pulse signal having a pulse number c satisfying c = n - m flows is the above second flow path. [[ID=,6]]

[0010] It may further include a control unit that controls the above flow path switching unit.

[0011] It may further include a detection unit that detects a change in the position of the above drive unit, and the above control unit may control the above flow path switching unit based on the detection result of the above detection unit.

[0012] The above control unit further controls the operation of the above drive unit. The above control unit In the case where n < m, after operating the above drive unit based on the above discharge pulse signal, it operates based on the pulse signal having the above pulse number b. In the case where n > m, after operating the above drive unit based on the above discharge pulse signal, it may operate based on the pulse signal having the above pulse number c.

[0013] The above second flow path may flow the liquid transferred from the above liquid transfer pump to the above liquid storage unit. The above drive unit may be configured to be rotatable in a direction opposite to the rotation direction during the discharge of the above liquid. The first flow path may be configured by a first tube, and the second flow path may be configured by a second tube, and the flexible tube, the first tube, and the second tube may be configured to be replaceable. The flow path switching unit may be a pinch valve.

[0014] In order to achieve the above object, a liquid ejection control method according to one embodiment of the present technology comprises a liquid transfer pump having a flexible tube through which liquid can flow, a pressing unit that presses the flexible tube from the outer surface side to send the liquid from one end of the flexible tube to the other end, and a drive unit that rotates and drives the pressing unit, in which a predetermined amount of liquid is transferred into a first flow path on the ejection side, and then the liquid flows into a second flow path different from the first flow path until the drive unit moves to a position where the liquid starts to flow into the first flow path.

[0015] According to this configuration, ejection is performed so that the flexible tube is always pressed at the same position by the pressing portion, so that the amount of ejection each time can be controlled with high precision.

[0016] In order to achieve the above object, a filling method according to one embodiment of the present technology includes a liquid transfer pump having a flexible tube through which liquid can flow, a pressing unit that presses the flexible tube from the outer surface side to send the liquid from one end of the flexible tube to the other end, and a drive unit that rotates and drives the pressing unit, and the liquid is transferred from the pump by ejecting a predetermined amount of liquid into a container through a first flow path to fill the container, and then the liquid flows out into a second flow path different from the first flow path until the drive unit moves to a position where the liquid starts to flow out into the first flow path.

[0017] With this configuration, the flexible tube is always pressed at the same position each time the liquid is dispensed, so that the container can be filled with a constant amount of liquid with high precision. [Brief explanation of the drawings]

[0018] [Figure 1]FIG. 1 is a schematic diagram illustrating a configuration of a liquid ejection device. [Figure 2] 3A and 3B are schematic diagrams illustrating the configuration of a liquid transfer pump that is a part of the liquid ejection device. [Figure 3] 5A and 5B are schematic diagrams illustrating the direction in which liquid flows in the liquid ejection device. [Figure 4] 5A to 5C are diagrams illustrating the flow of operations in the liquid ejection device. [Figure 5] FIG. 4 is a flowchart of a liquid ejection control method for the liquid ejection device. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, the present technology will be described with reference to the drawings. [Configuration of liquid ejection device] 1 is a schematic diagram illustrating the overall configuration of a liquid ejection device, in which the white arrows indicate the flow of liquid. FIG. 2 is a partial schematic diagram of the liquid ejection device, and is a diagram mainly illustrating the structure of a liquid transfer pump that constitutes a part of the liquid ejection device.

[0020] As shown in FIG. 1, the liquid ejection device 1 includes a liquid tank 2, a liquid transfer pump 3, a first tube 11, a second tube 12, an ejection head 4, a three-way valve 5, a control device 6, and a three-way valve drive unit 7. The liquid ejection device 1 is configured so that a liquid such as a chemical solution stored in a liquid tank 2 can be transferred by a liquid transfer pump 3 and ejected from an ejection head 4 into a container 9. The liquid ejection device 1 can also be said to be a filling device that dispenses and fills the container 9 with the liquid. Although the example described here is one in which a container is filled with liquid, the destination of the liquid ejected from the liquid ejection device 1 is not limited to a container. For example, the present invention can also be applied to a configuration in which a liquid is ejected from the liquid ejection device as a coating liquid onto a coating target. The liquid ejection device 1 is configured to be able to dispense a predetermined amount of liquid. For example, the ejection amount can be set to 0.01 ml / min to 100 ml / min, and the liquid ejection device 1 of this embodiment is particularly effective in enabling accurate dispensing even at small ejection amounts such as 0.01 ml / min to 1.0 ml / min.

[0021] The liquid tank 2 is a liquid storage unit that stores the liquid to be discharged from the liquid discharge device 1 to the container 9. The liquid transfer pump 3 transfers the liquid contained in the liquid tank 2 to the first tube 11 or the second tube 12. As shown in Fig. 2, the liquid transfer pump 3 has a third tube 13, a plurality of eccentric cams 32, a servo motor 33, and a servo driver 34. The configuration of each will be described below.

[0022] The third tube 13 has a hollow, elongated shape, and the hollow portion serves as a flow path. One end of the third tube 13 is connected to the liquid tank 2, and the other end is connected to the three-way valve 5. At least the portion of the third tube 13 that is pressed by the eccentric cam 32 (described later) is flexible. Here, the portion of the third tube 13 that is pressed by the eccentric cam 32 is referred to as the flexible tube 31. The flexible tube 31 allows the liquid supplied from the liquid tank 2 to flow through. The flexible tube 31 is made of an elastic material that is pressed from its outer circumferential surface by the eccentric cam 32, causing it to deform, and returns to its original shape when released from the pressure. As the multiple eccentric cams 32 operate, they press the flexible tube 31 in order from one end to the other, squeezing the flexible tube 31 in one direction, causing the liquid supplied into the flexible tube 31 to be sent from one end to the other.

[0023] The servo motor 33 has a motor 331 as a drive unit and an encoder 333 as a detection unit. The motor 331 has a rotating shaft 332. The motor 331 is driven to rotate by a drive current supplied from a servo driver 34 based on a motor control signal (typically a pulse signal) related to the motor's operation. In conjunction with this rotation, the multiple eccentric cams 32 are driven to rotate and press the flexible tube 31. The motor control signal is a signal commanding the operation of the motor. Herein, the rotation of the motor 331 when the liquid transfer pump 3 transfers liquid from the liquid tank 2 to the first tube 11 or the second tube 12 is referred to as forward rotation. Rotation in the direction opposite to this forward rotation is referred to as reverse rotation. The direction of forward rotation is the direction of rotation when liquid is being discharged or circulated. Hereinafter, "forward rotation" will simply be referred to as "rotation." The encoder 333 is a rotational position detector that detects changes in the position of the motor 331. The encoder 333 is coupled to the rotating shaft 332 of the motor 331. The encoder 333 outputs a detection signal, for example, a number of pulses (pulse signal) corresponding to the amount of rotation. The output signal from the encoder (sometimes referred to as the detection signal) includes information on the rotational position (rotational angle information) and rotational speed of the motor 331. For example, the encoder 333 can be a detector that outputs A-phase, B-phase, and Z-phase pulse signals. The A-phase and B-phase pulse signals are proportional to the speed. The B-phase outputs a pulse with a phase difference of 90° with respect to the A-phase, and the direction of rotation is determined by the level of the B-phase signal at the rising edge of the A-phase pulse. The Z-phase pulse signal is a pulse signal that is generated each time the motor rotates. The encoder 333 generates a detection signal indicating the detected operation of the motor 331 and transmits the detection signal to the servo driver 34 .

[0024] The multiple eccentric cams 32 rotate in conjunction with the movement of the rotary shaft 332 of the motor 331, and press against the flexible tube 31. The multiple eccentric cams 32 are pressing parts that press against the flexible tube 31. These eccentric cams 32 press against the flexible tube 31 in order from one end to the other, thereby allowing the liquid supplied into the flexible tube 31 to be sent from one end to the other.

[0025] The servo driver 34 receives a motor control signal (motor operation command signal) relating to the operation of the motor 331 from the control device 6, and supplies a drive current to the motor 331 so that the operation of the motor 331 follows the command value. Furthermore, the servo driver 34 receives the detection signal output from the encoder 333. The servo driver 34 executes servo control related to the driving of the motor 331 based on the motor control signal and the detection signal from the encoder 333. That is, the servo driver 34 calculates a command value related to the operation of the motor 331 based on the motor control signal and the detection signal from the encoder 333, and supplies a drive current to the motor 331 so that the operation of the motor 331 follows the command value.

[0026] The first tube 11 and the second tube 12 have a hollow, elongated shape, and the hollow portion serves as a flow path. The first tube 11 constitutes a first flow path through which the liquid transferred from the liquid transfer pump 3 flows. The first tube 11 has a discharge head 4 at one end and is connected at the other end to a three-way valve 5. The liquid transferred from the liquid transfer pump 3 and flowing into the first tube 11 is discharged from the discharge head 4 into a container 9. The second tube 12 constitutes a second flow path through which the liquid transferred from the liquid transfer pump 3 flows. The first flow path and the second flow path are different. One end of the second tube 12 is connected to the liquid tank 2, and the other end is connected to the three-way valve 5. The liquid transferred from the liquid transfer pump 3 and flowing into the second tube 12 is supplied to the liquid tank 2. In this way, the first tube 11 functions as a discharge-side tube, and the second tube 12 functions as a circulation-side tube. In the liquid ejection device 1, the liquid-contacting parts that come into direct contact with the liquid are the insides of the first tube 11, the second tube 12, and the third tube 13 having the flexible tube 31. In the liquid ejection device 1, these tubes are configured to be replaceable and disposable. Replacing the tubes eliminates the need for cleaning and sterilization processes for the liquid-contacting parts during setup, improving workability and safety. It also makes it possible to avoid the risk of contamination of the liquid.

[0027] The three-way valve 5 is a flow path switching unit that switches the flow path for the liquid transferred from the liquid transfer pump 3 between the first tube 11 and the second tube 12, and is a flow path opening / closing valve. The three-way valve 5 has an inlet 53 into which the liquid transferred from the liquid transfer pump 3 flows, a first outlet 51 through which the liquid transferred from the liquid transfer pump 3 flows out via the inlet 53 into the first tube 11, and a second outlet 52 through which the liquid transferred from the liquid transfer pump 3 flows out via the inlet 53 into the second tube 12. In the three-way valve 5, the opening and closing of the first outlet port 51 and the second outlet port 52 is controlled by the three-way valve driving unit 7 based on a control signal from a control unit 61 of the control device 6, which will be described later. Note that the inlet port 53 is always open and is not provided with a valve.

[0028] FIG. 3 is a schematic diagram illustrating the direction in which the liquid flows in the liquid ejection device 1. As shown in FIG. 3(A), in the three-way valve 5, the first outlet 51 is opened and the second outlet 52 is closed, causing the liquid transferred by the liquid transfer pump 3 to flow into the first tube 11 on the discharge side. The liquid flowing into the first tube 11 is discharged into the container 9 and filled therein. 3(B), in the three-way valve 5, the second outlet 52 is opened and the first outlet 51 is closed, causing the liquid transferred by the liquid transfer pump 3 to flow into the second tube 12 on the circulation side. The liquid flowing into the second tube 12 flows into the liquid tank 2. A solenoid pinch valve can typically be used as the three-way valve 5, but is not limited to this. A pinch valve is more preferable because the liquid-contacting part can be only a tube, which allows the flow path to be kept clean at all times.

[0029] The three-way valve driving unit 7 controls the open / closed state of the three-way valve 5 based on a valve control signal transmitted from the control unit 61 of the control device 6.

[0030] The control device 6 includes a control unit 61 . An input operation unit (not shown), such as a touch panel or keyboard, is connected to the control device 6. From the input operation unit, for example, an operator of the liquid discharge device 1 inputs various commands such as the rotation speed, the number of rotations of the motor corresponding to the amount of liquid discharged per discharge, starting or stopping the discharge operation, changing the direction of rotation, etc. This various operational command information is transmitted to the control device 6.

[0031] The control unit 61 controls the open / closed state of the three-way valve 5. The control unit 61 may further control the operation of the motor 331. A personal computer, for example, can be used as the control device 6. The control unit 61 is composed of a CPU (Central Processing Unit) and the like. The CPU executes a control program related to the control of the open / closed state of the three-way valve 5 and the operation control of the motor 331. The control programs for controlling the open / closed state of the three-way valve 5 and the operation of the motor 331 can be stored in advance in a hard disk or ROM (Read Only Memory) that serves as a recording medium built into the control device 6. Alternatively, the control programs can be stored in a removable recording medium driven by a drive. Such removable recording media can be provided as so-called packaged software. Examples of removable recording media include flexible disks, CD-ROMs (Compact Disk Read Only Memory), MO (Magneto-Optical) disks, DVDs (Digital Versatile Discs), magnetic disks, and semiconductor memories. The programs can be installed into a computer from the removable recording medium, or downloaded to the control device via a communication network and installed on the built-in hard disk. The control programs will be described later.

[0032] Based on the various command information received, the control unit 61 transmits a motor control signal related to the operation of the motor 331 to the servo driver 34. Furthermore, the control unit 61 receives a detection signal from the encoder 333 from the servo driver 34, and generates a valve control signal for controlling the valve open / close state of the three-way valve 5 based on the detection signal.

[0033] Specifically, the control unit 61 transmits a discharge motor control signal to the servo driver 34 to transfer a predetermined amount of liquid so that the predetermined amount of liquid is filled into the container 9. The "predetermined amount" refers to the amount of liquid discharged in one go from the liquid discharge device 1. Hereinafter, the "predetermined amount of liquid" may be referred to as "liquid for discharge." The process of discharging the liquid into the container 9 is also referred to as the discharge process. Furthermore, as shown in Figure 3(A), the control unit 61 sends a valve control signal to the three-way valve drive unit 7 so that the three-way valve 5 is controlled so that the first outlet 51 is in an open state and the second outlet 52 is in a closed state while the liquid for discharge is being transferred by the liquid transfer pump 3 based on the discharge motor control signal. As a result, the liquid to be discharged transferred from the liquid transfer pump 3 flows into the first tube 11. The liquid flowing through the first tube 11 is dispensed at a predetermined discharge amount into the container 9. Here, in one discharge process, the position of the motor 331 at the start of the outflow of the liquid is referred to as the reference position, and the position of the motor 331 at the end of the outflow is referred to as the end position.

[0034] Next, after the liquid to be discharged is transferred to the first tube 11, the control unit 61 sends a phase alignment motor control signal to the servo driver 34 so that the motor 331 rotates from the end position to the reference position and returns. Furthermore, after the liquid to be discharged has been transferred to the first tube 11, the control unit 61 transmits a valve control signal to the three-way valve driving unit 7 to control the three-way valve 5 so that the liquid transferred by the liquid transfer pump 3 flows out into the second tube 12 based on the phase alignment motor control signal, as shown in Fig. 3(B). This valve control signal controls the three-way valve 5 so that the second outflow port 52 is in an open state and the first outflow port 51 is in a closed state. As a result, the liquid transferred from the liquid transfer pump 3 based on the phase alignment motor control signal flows into the second tube 12, and the motor 331 rotates from the end position to the reference position and returns. This movement of the motor 331 from the end position to the reference position is called phase alignment. The liquid flowing into the second tube 12 is circulated into the liquid tank 2. This process of circulating the liquid is called the circulation process. The phase of the motor refers to the positional relationship between the eccentric cam 32, which is the pressing part, and the motor 331. The above-mentioned "phase alignment" refers to rotating and moving the motor 331 so that the phase of the motor at the end of the liquid outflow in one discharge process matches the phase of the motor at the start of the outflow. A discharge step and a circulation step are alternately repeated in the liquid discharge device 1. In one discharge step, one container is filled with liquid.

[0035] In this way, the control unit 61 transmits the discharge motor control signal and the phase alignment motor control signal to the servo driver . Furthermore, the control unit 61 generates a valve control signal that controls the open / closed state of the valve in the three-way valve 5 so that the liquid transferred from the liquid transfer pump 3 based on the discharge motor control signal flows into the first tube 11, and the liquid transferred from the liquid transfer pump 3 based on the phase alignment motor control signal flows into the second tube 12, and sends this signal to the three-way valve drive unit 7.

[0036] By controlling the operation of the motor and the open / close state of the three-way valve as described above, the motor 331 is positioned at the reference position at the start of the next discharge. By performing this control during dispensing, the motor 331 is always positioned at the reference position at the start of each discharge process. Therefore, the position of the flexible tube 31 pressed by the eccentric cam 32 is always the same in each discharge process. The inner diameter of the flexible tube is not necessarily uniform, and it is difficult to machine the eccentric cam to the exact same dimensions as the reference dimensions, so there may be dimensional variations between the eccentric cams. In this embodiment, even if the inner diameter of the flexible tube is non-uniform or there are dimensional variations among the multiple eccentric cams, the position on the flexible tube pressed by the eccentric cam is controlled to always be the same in each discharge process, and each eccentric cam always presses the same position on the flexible tube, making it possible to stably control the discharge amount to a constant amount each time.In this way, the liquid discharger 1 is capable of highly accurate discharge.

[0037] As described above, the motor control signals related to the operation of the motor 331 include a motor control signal for discharge and a motor control signal for phase matching. The three-way valve 5 is controlled so that the liquid transferred by the liquid transfer pump 3 based on the motor control signal for discharge flows into the first tube 11 on the discharge side, and the liquid transferred by the liquid transfer pump 3 based on the motor control signal for phase matching flows into the second tube 12 on the circulation side. The liquid flowing into the second tube 12 is returned to the liquid tank 2. Thus, during phase alignment, the liquid transferred by the liquid transfer pump 3 is returned to the liquid tank 2, and the liquid circulates. Therefore, there is almost no waste of liquid, and the utilization efficiency of the liquid can be improved.

[0038] The control of the above three-way valve 5 will be described in more detail. The motor 331 of the liquid transfer pump 3 rotationally drives the eccentric cam 32 based on the drive current generated by the servo driver 34 based on the motor control signal. The motor control signal is typically a pulse signal. Let the number of pulses of the discharge motor control signal corresponding to one discharge amount be m (m > 0). The discharge motor control signal corresponding to one discharge amount may be referred to as a discharge pulse signal. Also, the phase alignment motor control signal may hereinafter be referred to as a phase alignment pulse signal. Let the number of pulses of the pulse signal required for the motor 331 to make one rotation be n (n > 0).

[0039] When n < m, the three-way valve 5 is controlled by the three-way valve drive unit 7 as follows based on the valve control signal transmitted from the control unit 61. That is, as shown in Fig. 3(A), the three-way valve 5 is controlled such that the first outflow portion 51 is in an open state and the second outflow portion 52 is in a closed state. Thereby, the liquid transferred from the liquid transfer pump 3 based on the discharge pulse signal with the number of pulses m flows into the first tube 11. After the completion of liquid transfer based on the discharge pulse signal, as shown in Fig. 3(B), the three-way valve 5 is controlled such that the first outflow portion 51 is in a closed state and the second outflow portion 52 is in an open state. Thereby, the liquid transferred from the liquid transfer pump 3 based on the pulse signal with the number of pulses b that satisfies m = an + b (a is an integer of 1 or more, b > 0, n > b) flows into the second tube 12. The pulse signal with the number of pulses b is a phase alignment pulse signal.

[0040] When n > m, the three-way valve 5 is controlled by the three-way valve drive unit 7 as follows based on the valve control signal transmitted from the control unit 61. That is, as shown in Fig. 3(A), the three-way valve 5 is controlled such that the first outflow portion 51 is in an open state and the second outflow portion 52 is in a closed state. Thereby, the liquid transferred from the liquid transfer pump 3 based on the discharge pulse signal of the pulse number m flows into the first tube 11. After the liquid transfer based on the discharge pulse signal is completed, as shown in Fig. 3(B), the three-way valve 5 is controlled such that the first outflow portion 51 is in a closed state and the second outflow portion 52 is in an open state. Thereby, the liquid transferred from the liquid transfer pump 3 based on the pulse signal of the pulse number c satisfying c = n - m (c > 0) flows into the second tube 12. The pulse signal of the pulse number c is a phase matching pulse signal.

[0041] An example of the control of the valve opening and closing state of the three-way valve 5 will be described with specific numerical values. Taking the case of n < m as an example, a motor 331 that rotates once every 500 pulses is used as a drive source, and the discharge amount per rotation is controlled by a rotation amount of 300 pulses. The encoder 333 outputs, for example, 500 pulses as the A-phase and B-phase outputs and 1 pulse as the Z-phase output when the motor 331 rotates once as a detection result. In this case, the liquid transfer pump 3 is controlled to operate based on the discharge pulse signal of 300 pulses and then to operate based on the phase matching pulse signal of 200 pulses. The three-way valve 5 is controlled by a valve control signal such that the liquid transferred from the liquid transfer pump 3 based on the discharge pulse signal flows into the first tube 11, and the liquid transferred from the liquid transfer pump 3 based on the phase matching pulse signal flows into the second tube 12. In other words, the discharge amount for one time corresponds to 0.6 rotations of the motor. In the discharge process, the first outflow portion 51 is set to an open state and the second outflow portion 52 is set to a closed state. After the discharge process, the motor 331 only needs to rotate 0.4 rotations to return from the end position to the reference position. During the period until it returns to this reference position, that is, in the phase matching process, the first outflow portion 51 is set to a closed state and the second outflow portion 52 is set to an open state. Based on the phase matching pulse signal, the motor 331 returns to the reference position, and in the discharge process based on the next discharge pulse signal, the rotation of the motor 331 starts from the reference position.

[0042] As an example, a case where n>m is taken, in which a motor 331 that rotates once per 500 pulses is used as a drive source, and the amount of ejection per rotation is controlled by 1300 pulses. As a detection result, the encoder 333 outputs 500 pulses as A-phase and B-phase outputs, and 1 pulse as Z-phase output, for example, when the motor 331 rotates once. In this case, the liquid transfer pump 3 is controlled to operate based on a 1300-pulse ejection pulse signal, and then based on a 200-pulse phase matching pulse signal. The three-way valve 5 is controlled by a valve control signal so that the liquid transferred from the liquid transfer pump 3 based on the ejection pulse signal flows into the first tube 11, and the liquid transferred from the liquid transfer pump 3 based on the phase matching pulse signal flows into the second tube 12. In other words, one discharge amount corresponds to 2.6 rotations of the motor 331, and during the discharge process, the first outlet 51 is set to an open state and the second outlet 52 is set to a closed state. After the discharge process, the motor 331 needs to rotate 0.4 times to return from the end position to the reference position, and during the period until it returns to this reference position, i.e., during the phase alignment process, the first outlet 51 is set to a closed state and the second outlet 52 is set to an open state. Driven by the phase alignment pulse signal, the motor 331 returns to the reference position, and during the discharge process based on the next discharge pulse signal, the motor 331 starts rotating from this reference position.

[0043] Generally, pumps using disposable tubes have poor liquid delivery and dispensing accuracy, and are considered unsuitable for use in applications requiring high repeatability. In contrast, in the liquid discharger 1 equipped with a pump using a tube according to the present embodiment, the motor's rotation start position for each discharge is controlled so that it always remains at the same position (reference position). This makes it possible to stably control the amount of liquid discharged each time to a constant amount, and can improve dispensing accuracy to approximately ±1%, which is comparable to that of a highly accurate volumetric metering pump. As described above, the liquid ejection device 1 of this embodiment allows for disposable liquid-contacting parts while achieving highly accurate ejection. Furthermore, by using a pinch valve for the three-way valve, the only disposable liquid-contacting part is the tube. Making the liquid-contacting parts disposable eliminates the need for cleaning and sterilization processes for the liquid-contacting parts, significantly shortening the operation time while ensuring the safety of the operator and significantly reducing the risk of liquid contamination. The three-way valve does not necessarily have to be a pinch valve; it may be a three-way valve with a liquid-contacting part, and the three-way valve may be replaceable. However, from the viewpoints of reducing the number of replacement parts and operability, it is preferable to use a pinch valve. Furthermore, in the liquid ejection device 1, the liquid transferred during phase alignment can be returned to the liquid tank 2, so no liquid is wasted and the efficiency of liquid use is improved. The destination to which the liquid transferred during phase alignment is supplied does not have to be the liquid tank, as long as it is a location different from the destination to which the liquid is ejected via the first tube 11 on the ejection side. However, as described above, from the perspective of the efficiency of liquid use, it is more preferable to circulate the liquid to the liquid tank. Furthermore, in the liquid ejection device 1, the three-way valve 5 is used to switch between liquid circulation and liquid ejection, so there is no need to move the ejection head when aligning the phase, which eliminates time loss during mass production and enables continuous liquid dispensing. Furthermore, motor 331 is configured to be rotatable in the direction opposite to the direction of rotation when dispensing liquid, which allows motor 331 to rotate in the opposite direction after dispensing is complete, returning the liquid remaining in the tube to the liquid tank, improving the efficiency of liquid usage.

[0044] [Liquid discharge control method, filling method] A description will now be given of a liquid ejection control method and a filling method using the above-described liquid ejection device 1. Here, a filling method for filling a container with liquid ejected by the liquid ejection control method will be taken as an example. FIG. 4 is a flow diagram illustrating the flow of operations in the liquid ejection device 1. FIG. 5 is a flow chart of a liquid ejection control method in the control unit 61 of the control device 6. The following description will be given with reference to FIGS.

[0045] 4, when the dispensing process in the liquid discharge device 1 is started, first, the first outlet 51 is closed, the second outlet 52 is opened, and the second tube 12 and the third tube 13 are filled with liquid. Thereafter, the second outlet 52 is closed, the first outlet 51 is opened, and the first tube 11 is filled with liquid (S1). In addition, operation command information input by, for example, an operator is transmitted to the control device 6.

[0046] As shown in FIG. 5, the control unit 61 of the control device 6 receives operation command information (S11). Based on the received operation command information, the control unit 61 sends a valve control signal to the three-way valve drive unit 7 to open the first outlet 51 and close the second outlet 52 in the three-way valve 5, and also sends a discharge pulse signal to the servo motor 33 (S12).

[0047] The three-way valve driver 7 controls the open / close state of the three-way valve 5 based on the valve control signal. The servo motor 33 receives the discharge pulse signal and supplies a drive current to the motor 331 so that the operation of the motor 331 follows the command value. As a result, as shown in Figure 4, in the three-way valve 5, the first outlet 51 is in an open state and the second outlet 52 is in a closed state (S2). The motor 331 of the liquid transfer pump 3 is driven based on the discharge pulse signal, and the liquid is transferred. The liquid transferred from the liquid transfer pump 3 flows into the first tube 11 and is discharged from the discharge head 4 attached to one end of the first tube 11 into the container 9 (S3), where it is filled (see Figure 3(A)).

[0048] As shown in FIG. 5, the control unit 61 acquires the detection signal detected by the encoder (S13). The control unit 61 detects the end of the discharge process based on the acquired detection signal. Thereafter, the control unit 61 transmits a valve control signal to the three-way valve driving unit 7, which opens the second outlet 52 and closes the first outlet 51 of the three-way valve 5. Furthermore, based on the detection signal, the control unit 61 generates a phase alignment pulse signal for rotating the motor so that the position of the motor at the time when one discharge is completed (end position) returns to the reference position, and transmits the phase alignment pulse signal to the servo motor 33 (S14).

[0049] The three-way valve driver 7 controls the open / close state of the three-way valve 5 based on the valve control signal. The servo motor 33 receives the phase alignment pulse signal and supplies a drive current to the motor 331 so that the operation of the motor 331 follows the command value. As a result, as shown in Figure 4, in the three-way valve 5, the second outlet 52 is in an open state and the first outlet 51 is in a closed state (S4). The motor 331 of the liquid transfer pump 3 is driven based on the phase alignment pulse signal to perform phase alignment, and the motor 331 returns to the reference position (S5). The liquid transferred from the liquid transfer pump 3 based on the phase alignment pulse signal flows into the second tube 12 and returns to the liquid tank 2 connected to one end of the second tube 12 (see Figure 3(B)).

[0050] As shown in FIG. 4, after the phase adjustment, the process returns to S2, and the ejection step and the phase adjustment step are repeated, and the liquid ejection device 1 performs continuous dispensing. In this embodiment, the motor rotation start position for each discharge is controlled to always be the same position (reference position), making it possible to stably control the amount of liquid discharged each time to a constant amount. Therefore, it is possible to fill each of the multiple containers 9 with liquid at a precise constant amount of discharge, thereby obtaining containers with little variation in the amount of liquid filled.

[0051] After the dispensing process is completed, the first outlet 51 and second outlet 52 of the three-way valve 5 are switched to the open state and the liquid transfer pump 3 is rotated in the reverse direction, so that all of the liquid in the tube can be returned to the liquid tank 2. This reduces the amount of liquid wasted and improves the efficiency of liquid use.

[0052] [Control Program] The control program for controlling the open / closed state of the three-way valve 5 controls the three-way valve 5 as follows. That is, the three-way valve 5 is controlled so that the flow path through which a predetermined amount of liquid transferred from the liquid transfer pump 3 flows out is the first tube (first flow path) 11. After the predetermined amount of liquid flows out, the three-way valve 5 is controlled so that the flow path through which the liquid transferred from the liquid transfer pump 3 flows out is the second tube (second flow path) 12 until the motor 331 moves to the position at which the liquid started to flow out to the first tube 11 (reference position).

[0053] The control program for the operation of the motor 331 controls the motor 331 as follows. That is, when the flow path through which the liquid transferred from the liquid transfer pump 3 flows is the first tube 11, the motor 331 is controlled by the discharge motor control signal so that a predetermined amount of liquid flows out. Then, after the predetermined amount of liquid has flowed out, when the flow path through which the liquid transferred from the liquid transfer pump 3 flows is the second tube 12, the motor 331 is controlled by the phase alignment motor control signal so that the motor 331 moves from the end position to the reference position.

[0054] The embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present technology. For example, although the liquid transfer pump in the above embodiment uses a servo motor, the present invention is not limited to this and may use, for example, a stepping motor. In this case, a detector (detection unit) such as an encoder that detects rotation information of the motor may be provided.

[0055] In addition, for example, in the above-described embodiment, the liquid transfer pump has been described as having a flexible tube arranged in a straight line, but is not limited to this. For example, the liquid transfer pump may have a flexible tube bent into a U-shape, and the flexible tube may be compressed from one end to the other end by a plurality of rollers as pressurizing units from the outer periphery thereof, thereby transferring the liquid in the tube. Even in this configuration, by adjusting the phase, it is possible to transfer the liquid by always pressing the same part of the flexible tube for each discharge, as in the above-described embodiment, and therefore it is possible to always discharge a stable amount of liquid.

[0056] Furthermore, for example, the liquid discharge device may further include a flow rate detector and a weight detector. The flow rate detector detects the amount of liquid transferred from the liquid transfer pump and flowing into the first tube, i.e., the flow rate of the discharged liquid. The weight detector is disposed below the container to be filled with liquid and detects the weight of the container before and after filling. The control unit may generate a motor control signal based on the flow rate detection result from the flow rate detection unit and a target discharge rate. The control unit may also calculate the filling amount by measuring the weight of the container before and after filling using a weight detector, and generate a motor control signal based on the filling amount. This makes it possible to always eject a stable, predetermined amount of liquid even if the tubes are replaced and the degree of variation in inner diameter varies between different tubes. The flow rate detector may be, for example, an electromagnetic flow rate sensor or a Coriolis flow rate sensor, and a non-contact flow rate sensor is preferable from the viewpoint of preventing contamination of the liquid. Also, a measurement method using a weight detector is preferable from the viewpoint of preventing contamination of the liquid, since it is a non-contact measurement method.

[0057] The present technology can also be configured as follows. (1) a flexible tube through which the liquid supplied from a liquid storage portion that stores the liquid can flow; A pressing part that presses the flexible tube from the outer peripheral surface side to send out the liquid from one end of the flexible tube to the other end, and a driving part that rotationally drives the pressing part, and has a liquid transfer pump, a first flow path through which the liquid transferred from the liquid transfer pump flows out, a second flow path different from the first flow path through which the liquid transferred from the liquid transfer pump flows out, a flow path switching part that sets the flow path through which the liquid transferred from the liquid transfer pump flows out as the first flow path or the second flow path. The flow path through which the liquid for discharge transferred from the liquid transfer pump flows out is set as the first flow path. After the liquid for discharge is transferred, until the driving part moves to the position at the start of the outflow of the liquid for discharge, the flow path through which the liquid transferred from the liquid transfer pump flows out is controlled to be the second flow path, A liquid discharge device comprising the above.

[0058] (2) The liquid discharge device according to (1) above, wherein the driving part of the liquid transfer pump is driven based on a pulse signal, when the number of pulses of the discharge pulse signal for transferring the liquid for discharge is m (m > 0), and the number of pulses of the pulse signal required for one rotation of the driving part is n (n > 0), when n < m, the flow path switching part sets the flow path through which the liquid transferred from the liquid transfer pump driven based on the discharge pulse signal flows out as the first flow path, and after the liquid for discharge is transferred, the flow path through which the liquid transferred from the liquid transfer pump driven based on the pulse signal of the pulse number b that satisfies m = an + b (a is an integer of 1 or more, b > 0, n > b) flows out is controlled to be the second flow path, when n > m, The above flow path switching unit uses the flow path through which the liquid transferred from the liquid transfer pump driven based on the above discharge pulse signal flows as the first flow path. After the liquid for discharge is transferred, it is controlled such that the flow path through which the liquid transferred from the liquid transfer pump driven based on the pulse signal of the pulse number c satisfying c = n - m flows is the second flow path. Liquid discharge device.

[0059] (3) The liquid discharge device according to (2) above, A control unit that controls the above flow path switching unit A liquid discharge device further comprising the same.

[0060] (4) The liquid discharge device according to (3) above, Further comprising a detection unit that detects a change in the position of the above drive unit, The above control unit controls the above flow path switching unit based on the detection result of the above detection unit Liquid discharge device.

[0061] (5) The liquid discharge device according to (3) or (4) above, The above control unit further controls the operation of the above drive unit, The above control unit, When n < m, after operating the above drive unit based on the above discharge pulse signal, operate it based on the pulse signal of the above pulse number b, When n > m, after operating the above drive unit based on the above discharge pulse signal, operate it based on the pulse signal of the above pulse number c Liquid discharge device.

[0062] (6) The liquid discharge device according to any one of (1) to (5) above, The above second flow path allows the liquid transferred from the above liquid transfer pump to flow to the above liquid storage unit Liquid discharge device.

[0063] (7) The liquid ejection device according to any one of (1) to (6) above, The drive unit is configured to be rotatable in a direction opposite to the direction of rotation when the liquid is ejected. Liquid discharge device.

[0064] (8) The liquid ejection device according to any one of (1) to (7) above, the first flow path is constituted by a first tube, and the second flow path is constituted by a second tube; The flexible tube, the first tube, and the second tube are configured to be replaceable. Liquid discharge device.

[0065] (9) The liquid ejection device according to any one of (1) to (8) above, The flow path switching unit is a pinch valve. Liquid discharge device.

[0066] (10) A liquid transfer pump includes a flexible tube through which a liquid can flow, a pressing unit that presses the flexible tube from the outer peripheral surface side to send the liquid from one end of the flexible tube to the other end, and a drive unit that rotates and drives the pressing unit. After a predetermined amount of liquid is transferred from the pump to a first flow path on the discharge side, the liquid flows into a second flow path different from the first flow path until the drive unit moves to a position at which the liquid starts to flow into the first flow path. Liquid ejection control method.

[0067] (11) A liquid transfer pump has a flexible tube through which a liquid can flow, a pressing unit that presses the flexible tube from the outer peripheral surface side to send the liquid from one end of the flexible tube to the other end, and a drive unit that rotates and drives the pressing unit. A predetermined amount of liquid is transferred from the liquid transfer pump and discharged into a container via a first flow path to fill the container, and then the liquid flows out into a second flow path different from the first flow path until the drive unit moves to a position at which the liquid starts to flow into the first flow path. Filling method. [Explanation of symbols]

[0068] 1...Liquid discharge device 2...Liquid tank (liquid storage section) 3...Liquid transfer pump 5...Three-way valve (flow path switching section) 9…Container 11...First tube (first flow path) 12...Second tube (second flow path) 61...Control unit 31...Flexible tube 32...Eccentric cam (pressure part) 331...Motor (drive unit) 333...Encoder (detection unit)

Claims

1. a flexible tube through which the liquid supplied from a liquid storage portion that stores the liquid can flow; a pressing unit that presses the flexible tube from an outer peripheral surface side to send the liquid from one end of the flexible tube to the other end; a drive unit that rotates the pressing unit; A liquid transfer pump; a first flow path through which the liquid transferred from the liquid transfer pump flows out; a second flow path different from the first flow path through which the liquid transferred from the liquid transfer pump flows out; a flow path switching unit that sets a flow path through which liquid transferred from the liquid transfer pump flows out as the first flow path or the second flow path, the flow path switching unit being controlled so that the flow path through which liquid for ejection transferred from the liquid transfer pump flows out is the first flow path, and that after the liquid for ejection has been transferred, the flow path through which liquid transferred from the liquid transfer pump flows out is the second flow path until the drive unit moves to a position at which the liquid for ejection starts to flow out; A liquid ejection device comprising:

2. The liquid ejection device according to claim 1 , the drive unit of the liquid transfer pump is driven based on a pulse signal, When the number of pulses of the ejection pulse signal for transporting the ejection liquid is m (m>0), and the number of pulses of the pulse signal required for one rotation of the drive unit is n (n>0), In the case of n<m, the flow path switching unit is controlled so that a flow path through which liquid transferred from the liquid transfer pump driven based on the ejection pulse signal flows out is set as the first flow path, and a flow path through which liquid transferred from the liquid transfer pump driven based on a pulse signal with a pulse number b that satisfies m=an+b (a is an integer of 1 or more, b>0, n>b) flows out after the ejection liquid has been transferred is set as the second flow path, In the case of n>m, The flow path switching unit is controlled so that a flow path through which liquid transferred from the liquid transfer pump, which is driven based on the ejection pulse signal, flows out is set as the first flow path, and a flow path through which liquid transferred from the liquid transfer pump, which is driven based on a pulse signal with a pulse number c that satisfies c=n-m after the liquid for ejection has been transferred, flows out is set as the second flow path. Liquid discharge device.

3. The liquid ejection device according to claim 2, A control unit that controls the flow path switching unit The liquid ejection device further comprises:

4. The liquid ejection device according to claim 3, a detection unit that detects a change in the position of the drive unit; The control unit controls the flow path switching unit based on the detection result of the detection unit. Liquid discharge device.

5. The liquid ejection device according to claim 3, The control unit further controls the operation of the drive unit, The control unit When n<m, the driving unit is operated based on the ejection pulse signal, and then based on the pulse signal having the pulse number b, In the case of n>m, the driving unit is operated based on the ejection pulse signal, and then based on the pulse signal of the pulse number c. Liquid discharge device.

6. The liquid ejection device according to claim 1 , The second flow path allows the liquid transferred from the liquid transfer pump to flow into the liquid storage portion. Liquid discharge device.

7. The liquid ejection device according to claim 6, The drive unit is configured to be rotatable in a direction opposite to the rotation direction when the liquid is ejected. Liquid discharge device.

8. The liquid ejection device according to claim 1 , the first flow path is formed by a first tube, and the second flow path is formed by a second tube; The flexible tube, the first tube, and the second tube are configured to be replaceable. Liquid discharge device.

9. The liquid ejection device according to claim 1 , The flow path switching unit is a pinch valve. Liquid discharge device.

10. A liquid transfer pump includes a flexible tube through which a liquid can flow, a pressing unit that presses the flexible tube from the outer peripheral surface side to send the liquid from one end of the flexible tube to the other end, and a drive unit that rotates and drives the pressing unit. After a predetermined amount of liquid is transferred from the pump to a first flow path on the discharge side, the liquid flows into a second flow path different from the first flow path until the drive unit moves to a position at which the liquid starts to flow into the first flow path. Liquid ejection control method.

11. A liquid transfer pump includes a flexible tube through which a liquid can flow, a pressing unit that presses the flexible tube from the outer peripheral surface side to send the liquid from one end of the flexible tube to the other end, and a drive unit that rotates and drives the pressing unit. A predetermined amount of liquid is discharged into a container through a first flow path to fill the container, and then the liquid flows out into a second flow path different from the first flow path until the drive unit moves to a position at which the liquid starts to flow out into the first flow path. Filling method.

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