Dispensing device and dispensing system

A dispensing device includes: a syringe including a nozzle; a first pump configured to generate a pressure to discharge a liquid in the syringe through the nozzle; and a control unit configured to, when discharging the liquid in the syringe, discharge a part of the liquid in the syringe with the pressure generated by the first pump and then cause the liquid in the syringe to run out under its own weight.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a dispensing device and a dispensing system.

2. Description of the Related Art

A dispensing device (dispenser) configured to discharge a liquid from a nozzle using a syringe, and the like, has been utilized for various purposes.

For example, Japanese Patent Application Laid-open Publication No. 2009-291103 discloses an automatic cell-culture apparatus including a dispensing device (pipette device) which is used in a pipetting operation with respect to a culture container. Further, Japanese Patent Application Laid-open Publication No. 2004-141857 discloses a dispensing device which can be used for a printer head of an ink-jet printer.

The dispensing device as described above discharges a liquid from the nozzle by applying a pressure to the liquid. For example, a common ink-jet printer discharges an ink drop by applying a pressure to the ink drop using a piezo element (piezoelectric element) or using air bubbles generated by heating. Further, for example, a continuous type (continuous discharging type) ink-jet printer or a dispensing device using a syringe is capable of generating a pressure using a pump and discharging a liquid.

However, in the case of dispensing a liquid using a pump, a liquid phase and a gas phase are easily mixed at the tip of the nozzle at the start and/or end of dispensing, which may cause a splatter and/or a bubble. If a splatter is generated, the liquid may splatter over something other than a liquid dispensing target, thereby contaminating the surroundings. Further, also in the case where a bubble is generated, the bubble may burst into splatters or the bubble at the tip of the nozzle may drip when the syringe is moved, thereby contaminating the surroundings.

In particular, such a dispensing device as to be used for a cell culture apparatus does not discharge a solution continuously, which is different from the case with a continuous type ink-jet printer, and thus, the splatter and/or bubble may be generated every start and/or end of dispensing. Therefore, when a solution is discharged using a pump, the solution may splatter over the outside of a dish (culture dish) or drip off the dish, which may result in contamination.

SUMMARY OF THE INVENTION

A dispensing device according to an aspect of the present disclosure includes: a syringe including a nozzle; a first pump configured to generate pressure for discharging liquid in the syringe through the nozzle; and a control unit configured to discharge the liquid in the syringe by discharging a part of the liquid in the syringe using pressure generated by the first pump and then causing the liquid in the syringe to flow out due to its own weight.

Other features of the present disclosure will become apparent from descriptions of the present specification and of the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION

At least the following details will become apparent from descriptions of the present specification and of the accompanying drawings.

===Configuration of Dispensing System and Dispensing Apparatus===

A configuration of a dispensing system and a dispensing device according to an embodiment of the present disclosure will be hereinafter described with reference toFIG. 1andFIG. 2.

FIG. 2depicts a configuration of a cell culture apparatus as an example of the application of the dispensing system including the dispensing device according to an embodiment of the present disclosure. The dispensing system (cell culture apparatus) illustrated inFIG. 2includes: a syringe1configured to dispense a liquid (dispensing solution such as a culture medium); and a dish5, configured to contain a culture medium, as a target to which the liquid is to be dispensed, and further includes a syringe drive portion3and a dish drive portion4configured to drive the syringe1and the dish5, respectively. The syringe1includes a nozzle11.

Note that the syringe drive portion3is capable of controlling the position and posture of the nozzle11by controlling the position and posture of the syringe1, and the dish drive portion4is capable of controlling the position, posture, and further rotation, for example, of the dish5. Under the control of the syringe drive portion3and the dish drive portion4, the relative position between the syringe1(nozzle11) and the dispensing target can be controlled, and the syringe1(nozzle11) can be relatively moved to the position at which the liquid is to be dispensed to the target. The syringe drive portion3and the dish drive portion4are hereinafter collectively referred to as a drive portion.

The dispensing device depicted inFIG. 1includes a control unit2, a filter12, pumps P1and P2, and valves V1to V3, in addition to the syringe1. The control unit2is configured to output control signals Sp1, Sp2, and Sv1to Sv3for controlling the pumps and the valves, respectively.

The (first) pump P1is a discharge pump configured to take in external air to the syringe1and generate a pressure to discharge the liquid in the syringe1through the nozzle11. The (second) pump P2is a suction pump configured to discharge the gas (air) in the syringe1and generate a pressure (negative pressure) and draw the liquid into the syringe1through the nozzle11.

The (first) valve V1is connected so as to open/close a (first) flow path between the syringe1and the pump P1. The (second) valve V2is connected so as to open/close a (second) flow path between the syringe1and external air. The (third) valve V3is connected so as to open/close a (third) flow path between the syringe1and the pump P2. Note that, for example, a solenoid valve and a motor-operated pinch valve, which can be controlled by a control signal, can be used as the valves.

The first to the third flow paths join and branch at one point, and the filter12such as a membrane filter is inserted into a flow path between the converging-and-diverging point and the syringe1, in order to prevent contamination of the liquid in the syringe1which would be caused by unwanted bacteria mixing therewith. Further, flow paths between external air and the pumps P1, P2as well as the valve V2may converge and diverge as appropriate.

===First Control of Dispensing Apparatus===

The operation of the dispensing device according to an embodiment of the present disclosure is hereinafter described with reference toFIG. 3toFIG. 8.

FIG. 3illustrates one example of a series of operations of filling and dispensing the liquid using the dispensing device according to an embodiment of the present disclosure.FIG. 4illustrates the control flow of the dispensing device when the filling and dispensing operations are performed. InFIG. 3, the dispensing device performs a series of filling/dispensing operations including drawing the liquid such as a medium solution stored in a reservoir6into the syringe1(filling operation), discharging the liquid in the syringe1to the dish5(dispensing operation), and thereafter discharging the liquid, bubbles, and the like, remaining in the syringe1to a waste liquid tank7(disposing operation).

The dispensing device can draw in the liquid from the dish5(filling operation) and discharge the liquid into the reservoir6(dispensing operation), can draw in the liquid from the dish5(filling operation) and discharge the liquid into the dish5(dispensing operation), or can draw in the liquid from the reservoir6(filling operation) and discharge the liquid into the reservoir6(dispensing operation). Further, the dispensing device can draw in the liquid from the reservoir6(filling operation) and discharge the liquid into the waste liquid tank7(disposing operation). Hereinafter, in any case, positions to which the syringe1(nozzle11) is to be moved to perform the filling operation, the dispensing operation, and the disposing operation are referred to as a filling position, a dispensing position, and a disposing position, respectively.

InFIG. 4, when the dispensing device starts a series of filling and dispensing operations (S11), first, the syringe1is moved to the filling position (reservoir6inFIG. 3) under the control of the drive portion (S12), and the filling operation is performed (S13). In the filling operation, as depicted inFIG. 5, under the control of the control unit2, the pump P1is stopped, the pump P2is driven with the valves V1and V2closed, and the valve3is opened, thereby drawing the liquid into the syringe1using the pressure (negative pressure) generated by the pump P2(pump driven suction).

Next, in the dispensing device, the syringe1is moved to the dispensing position (dish5inFIG. 3) under the control of the drive portion (S21), and the dispensing operation is performed (S22and S23). The dispensing operation according to an embodiment of the present disclosure includes: the dispensing operation1(S22) which is performed from the start of dispensing; and the dispensing operation2(S23) which is performed subsequent to the dispensing operation1.

In the dispensing operation1, as depicted inFIG. 6, the pump P2is stopped and the valve V3is closed with the valve V2closed, and further the pump P1is driven and the valve V1is opened, under the control of the control unit2, thereby discharging a part of the liquid in the syringe1using the pressure generated by the pump P1(pump driven discharge). In the dispensing operation2, as depicted inFIG. 7, the pump P2is stopped, the pump P1is stopped as well as the valve V1is closed with the valve V3closed, and the valve V2is opened, under the control of the control unit2, thereby causing the liquid in the syringe1to run out under its own weight, that is, free-fall. In an embodiment of the present disclosure, flowing out of the liquid in such a free-fall is referred to as free-fall discharge.

As such, the dispensing device according to an embodiment of the present disclosure performs the dispensing operation1from the start of dispensing, and performs the dispensing operation2after the dispensing operation1. Thus, after quickly performing dispensing by the pump driven discharge, only the liquid can be gradually dispensed in the free-fall discharge, thereby being able to suppress generation of droplets and bubbles at the end of dispensing, and prevent the contamination of something other than the liquid dispensing target.

Here,FIG. 8depicts, by way of example, each operation time of the dispensing operations1and2when dispensing 6 ml of a liquid using the pump1, which is configured to discharge a liquid at 5 ml/s. InFIG. 8, a large part (a little under 90%) of the liquid in the syringe1is discharged from the nozzle11by performing the dispensing operation1for 1.04 seconds from the start of dispensing. Subsequently, the dispensing operation2is performed for 3.5 seconds, thereby causing substantially all of the remaining liquid (a little over 10%) in the syringe1to run out from the nozzle11.

Note that, at this time in the dispensing operation2, a very small amount of the liquid can remain in the syringe1and/or the nozzle11by the surface tension of the liquid. Therefore, the bubbles, which are generated when the final liquid drops are forcibly discharged by the pump driven discharge, and the droplets, which are generated by the burst of the bubbles, can be suppressed. Further, the inner diameter of the discharge port (tip) of the nozzle11is set in consideration of the surface tension of the liquid to be dispensed and the like, and in an embodiment of the present disclosure, the inner diameter is assumed to be approximately 0.25 mm to 5.0 mm, by way of example.

Further, in an embodiment of the present disclosure, the amount of the liquid to be discharged by the dispensing operation1is set in consideration of an error in fluid delivery volume in the pump. For example, when an error in the fluid delivery volume is within ±10%, setting is made such that a little under 90% of the whole discharge amount is discharged by the dispensing operation1, so that the amount corresponding to an error in the fluid delivery volume remains in the syringe1without the whole amount being discharged by the pump driven discharge. Thus, generation of bubbles and droplets is avoided, which would be generated if the pump driven discharge where performed to the end.

Next, the dispensing device performs a dispensing finishing operation (S31). In the dispensing finishing operation, in order to prevent droplets and bubbles from dropping from the nozzle11which is caused by the movement of the syringe1, for example, the tip of the nozzle11is brought into contact with the liquid surface or the end face of the dish5under the control of the drive portion, thereby removing droplets and bubbles at the tip of the nozzle11.

Finally, the dispensing device moves the syringe1to the liquid disposing position (waste liquid tank7inFIG. 3) under the control of the drive portion (S32), the disposing operation is performed (S33), and a series of the filling and dispensing operations ends (S34). In the disposing operation, similarly to the dispensing operation1, the pump driven discharge is performed under the control of the control unit2, so that the liquid, bubbles, etc., remaining in the syringe1are discharged into the waste liquid tank7, using the pressure generated by the pump P1(pump driven discharge). Note that it is desirable to take measures so as not to contaminate the surroundings even if the pump driven discharge is performed, such that the disposing operation is performed, for example, with the nozzle11being deeply inserted into the waste liquid tank7having a sufficient depth and with the tip of the nozzle11being brought into contact with the inner wall of the waste liquid tank7.

===Another Configuration Example of Dispensing Apparatus===

In an embodiment described above, the control unit2of the dispensing device outputs control signals for controlling the two pumps P1and P2and the three valves V1to V3, but it is not limited thereto. For example, as depicted inFIG. 9, a check valve CV which does not require the control of the control unit2may be used as the second valve in place of the valve V2. In the dispensing device, the check valve CV is connected so as to open/close the (second) flow path between external air and the flow path between the pump P1and the valve V1, and allow external air to flow in but prevent air from flowing out to external air.

When the check valve CV is used, in the filling operation, the pump P1is stopped, and the pump P2is driven as well as the valve V3is opened with the valve V1closed, under the control of the control unit2, as depicted inFIG. 10, thereby being able to perform the pump driven suction.

In the dispensing operation1, as depicted inFIG. 11, under the control of the control unit2, the pump P2is stopped and the valve V3is closed, and further the pump P1is driven and the valve V1is opened. In this case, since the check valve CV is closed by the pressure generated by the pump P1, the pump driven discharge can be performed.

Further, in the dispensing operation2, as depicted inFIG. 12, the pump P2is stopped, the valve V3is closed, and the pump P1is stopped with the valve V1open, under the control of the control unit2. In this case, since the check valve CV is opened by the pressure (negative pressure) applied under its own weight of the liquid in the syringe1, external air can be flown into the syringe1through the check valve CV and the valve V1, thereby being able to perform the free-fall discharge.

As such, in the dispensing device depicted inFIG. 9, the control unit2only has to output the control signals for controlling the two pumps P1and P2and the two valves V1and V3, thereby being able to reduce the control signals. However, in the dispensing device, the pressure for opening the check valve CV is only the pressure (negative pressure) under its own weight of the liquid in the syringe1, and thus there exists a possibility that the check valve CV is not sufficiently opened depending on the condition such as a shape of the nozzle11and the viscosity of the liquid. Whereas, in the dispensing device depicted inFIG. 1, the free-fall discharge can be reliably performed by controlling the valve V2.

As has been described, in the dispensing device depicted inFIG. 1andFIG. 9, the dispensing operation1is performed from the start of dispensing, and the dispensing operation2is performed after the dispensing operation1, thereby being able to perform quick dispensing by the pump driven discharge, and thereafter gradually dispense only the liquid in the free-fall discharge. Thus, splatters and bubbles are prevented from being generated at the end of dispensing, thereby being able to prevent contamination of something other than the liquid dispensing target.

Further, in the dispensing device depicted inFIG. 1, the control unit2controls the valve V1for opening/closing the (first) flow path between the syringe1and the pump P1for discharge and the valve V2for opening/closing the (second) flow path between the syringe1and external air, thereby being able to reliably perform the free-fall discharge after performing the pump driven discharge.

===Second Control of Dispensing Apparatus===

Next, a description will be give of second control of the dispensing device according to an embodiment of the present disclosure.

FIG. 15depicts a flow of the second control of the dispensing device when the filling and dispensing operations are performed.

InFIG. 15, when the dispensing device starts a series of the filling and dispensing operations (S11A), firstly, the syringe1is moved to the filling position (reservoir6inFIG. 3) under the control of the drive portion (S12A), and the filling operation is performed (S13A). In the filling operation, as depicted inFIG. 5, the pump P1is stopped, and the pump P2is driven as well as the valve V3is opened with the valves V1and V2closed, under the control of the control unit2, thereby drawing the liquid into the syringe1by the pressure (negative pressure) generated by the pump P2(pump driven suction).

Next, in the dispensing device, the syringe1is moved to the dispensing position (dish5inFIG. 3) under the control of the drive portion (S21A) and the dispensing operation is performed (S22A and S23A). The dispensing operation according to an embodiment of the present disclosure includes the dispensing operation2(S22A), which is performed at the start of dispensing, and the dispensing operation1(S23A), which is performed subsequent to the dispensing operation2.

In the dispensing operation2, as depicted inFIG. 7, the pump P1is stopped, the pump P2is stopped as well as the valve V3is closed with the valve V1closed, and the valve V2is opened, under the control of the control unit2, thereby causing a part of the liquid in the syringe1to run out under its own weight, that is, free-fall. In an embodiment of the present disclosure, flowing out of the liquid in such a free-fall is referred to as free-fall discharge. Further, in the dispensing operation1, as depicted inFIG. 6, the pump P2is stopped, the valve V2is closed and the pump P1is driven as well as the valve V1is opened with the valve V3closed, under the control of the control unit2, thereby discharging the liquid in the syringe1using the pressure generated by the pump P1(pump driven discharge).

As such, the dispensing device according to an embodiment of the present disclosure performs the dispensing operation2at the start of dispensing, and then performs the dispensing operation1after the dispensing operation2. Therefore, it becomes possible to gradually start dispensing in a free-fall discharge and perform the pump driven discharge after removing the gas phase at the tip of the nozzle11, thereby being able to suppress generation of splatters and bubbles at the start of dispensing, and prevent contamination of something other than the liquid dispensing target.

Here,FIG. 16depicts each operation time of the dispensing operations1and2when dispensing 6 ml of the liquid using the pump P1, which is configured to discharge the liquid at 5 ml/s, by way of example. InFIG. 16, when starting dispensing, a small amount (about one drop or two) of the liquid in the syringe1runs out from the nozzle11by performing the dispensing operation2for one second. Further, substantially all of the liquid in the syringe1is discharged from the nozzle11, by subsequently performing the dispensing operation1for 1.2 seconds. Note that, although the dispensing operation1is performed for 1.2 seconds at 5 ml/s, a small amount of liquid and/or bubbles may remain in the syringe1in actuality.

Next, the dispensing device performs the dispensing finishing operation (S31A). In the dispensing finishing operation, in order to prevent a droplet and a bubble from dripping from the nozzle11due to the movement of the syringe1, for example, the tip of the nozzle11is brought into contact with the liquid surface or the end surface of the dish5under the control of the drive portion, thereby removing a droplet and a bubble at the tip of the nozzle11.

Finally, the dispensing device moves the syringe1to the liquid disposing position (waste liquid tank7inFIG. 3) under the control of the drive portion (S32A), performs an operation of disposing the waste liquid (S33A), and finishes a series of the filling and dispensing operations (S34A).

Incidentally, when using the check valve CV as depicted in another configuration example inFIG. 9, the pump P1is stopped, and the pump P2is driven as well as the valve V3is opened with the valve V1closed, under the control of the control unit2, in the filling operation as depicted inFIG. 10, thereby being able to perform the pump driven suction.

===Another Control Example of Dispensing Apparatus===

In an embodiment described above, although the dispensing device discharges substantially all of the liquid in the syringe1by performing the dispensing operation1, after discharging a small amount of the liquid in the syringe1by performing the dispensing operation2when starting dispensing, it is not limited thereto. For example, as depicted inFIG. 13, the dispensing operation2may be further performed after the dispensing operation1.

Here,FIG. 14illustrates each operation time of the dispensing operations1and2when dispensing 6 ml of the liquid under the control depicted inFIG. 13using the pump P1, which is configured to discharge the liquid at 5 ml/s, by way of example. InFIG. 14, when starting dispensing, a small amount (about one drop or two) of the liquid in the syringe1runs out from the nozzle11by performing the dispensing operation2for one second, similarly toFIG. 16. Further, by subsequently performing the dispensing operation1for 1.04 seconds, substantially all (a little under 90%) of the liquid in the syringe1is discharged from the nozzle11. Furthermore, the dispensing operation2is subsequently performed for 3.5 seconds, thereby causing substantially all of the remaining liquid (a little over 10%) in the syringe1to run out from the nozzle11.

Note that, in the final dispensing operation2, a very small amount of the liquid can remain in the syringe1or the nozzle11by the surface tension of the liquid. Thus, bubbles, which would be generated when the final droplet of the liquid were forcibly discharged by the pump driven discharge, and/or splatters, which would be generated by the burst of the bubble, can be suppressed. Further, the inner diameter of the discharge port (tip) of the nozzle11is set in consideration of the surface tension of the dispensing liquid, and the like. In an embodiment of the present disclosure, the inner diameter is assumed to be approximately 0.25 mm to 5.0 mm, by way of example.

Further, in an embodiment of the present disclosure, the amount of the liquid to be discharged by the dispensing operation1is set in consideration of an error in fluid delivery volume in the pump. For example, when an error in the fluid delivery volume is within ±10%, the amount is set such that a little under 90% of the whole discharge amount is to be discharged by the dispensing operation1, so that the amount corresponding to the error in the fluid delivery volume remains in the syringe1without the whole amount of the liquid being discharged by the pump driven discharge. Thus, generation of the bubbles and/or splatters can be avoided, which would be generated if the pump driven discharge were performed to the end.

As such, in the control flow illustrated inFIG. 13, the dispensing operation2is performed when starting dispensing, the dispensing operation1is performed after the dispensing operation2, and the dispensing operation2is further performed after the dispensing operation1. Therefore, it becomes possible to gradually dispense only the liquid in the free-fall discharge after quick dispensing by the pump driven discharge, thereby being able to suppress generation of the splatters and bubbles at the end of the dispensing and prevent contamination of something other than the liquid dispensing target.

As has been described, in the dispensing device depicted inFIG. 1andFIG. 9, the dispensing operation2is performed at the start of dispensing and the dispensing operation1is performed after the dispensing operation2, thereby being able to gradually start dispensing in the free-fall discharge and perform the pump driven discharge after the removal of the gas phase at the tip of the nozzle11. Thus, generation of the splatter and bubble at the start of dispensing can be suppressed, and contamination of something other than the liquid dispensing target can be prevented.

Further, in the dispensing device depicted inFIG. 1, the control unit2controls the valve V1configured to open/close the (first) flow path between the syringe1and the pump P1for discharge; and the valve V2configured to open/close the (second) flow path between the syringe1and external air, thereby being able to perform the pump driven discharge after reliably performing the free-fall discharge.

Further, generation of splatter or bubble at the end of the dispensing can be suppressed, and contamination of something other than the liquid dispensing target can be prevented, by further performing the dispensing operation2after the dispensing operation1.

Further, in the dispensing device illustrated inFIG. 9, the control signal Sv2for controlling the second valve, which is to be outputted from the control unit2, can be reduced by adopting the check valve CV, which is configured to open/close the (second) flow path between external air and the flow path between the valve V1and the pump P1for discharge, and allow external air to flow in but prevent air from flowing out to external air.

Further, the control unit2further controls the valve V3configured to open/close the (third) flow path between the syringe1and the pump P2for suction, thereby being able to perform a series of filling/dispensing operations including a filling operation and a dispensing operation.

Further, a large part of the liquid in the syringe1is dispensed by the pump driven discharge and thereafter the remaining liquid in the syringe1is dispensed in the free-fall discharge, thereby being able to reduce the time period required for the dispensing operation while preventing the contamination of something other than the liquid dispensing target.

Further, in the dispensing system depicted inFIG. 2, the syringe drive portion3and the dish drive portion4can relatively move the syringe1(nozzle11) to the dispensing position, by controlling the relative position between the syringe1(nozzle11) and the liquid dispensing target.

Note that the above embodiments of the present disclosure are simply for facilitating the understanding of the present disclosure and are not in any way to be construed as limiting the present disclosure. The present disclosure may variously be changed or altered without departing from its spirit and encompass equivalents thereof.

In an embodiment of the present disclosure, a description has been given of the case where the cell culture apparatus is used as an example of the application of the dispensing system including the dispensing device, but it is not limited thereto. The liquid to be dispensed by the dispensing device may be other liquid, such as ink or adhesive, which needs to be prevented from contaminating something other than the liquid dispensing target.