JP2002214242A - Liquid dispensing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid dispensing device and method capable of improving discharge accuracy by preventing a liquid from adhering to a discharge opening of a liquid holding member. SOLUTION: The liquid dispensing device is provided with a channel member 34 for holding the liquid inside, a syringe piston pump 27 for drawing the liquid in the channel member 34, and a laminated piezoelectric element 32 for generating discharge pressure for discharging the liquid held in the channel member 34, and a micro amount of the liquid is discharged from an opening 39 of the channel member 34. The syringe piston pump 27 is driven and controlled in such a way as to draw the liquid adhering to a face of the opening 39 in the channel member 34 after the completion of liquid drawing operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid dispensing apparatus and a liquid dispensing method for medical use for dispensing a small amount of a liquid such as a reagent or a chemical solution.

[0002]

2. Description of the Related Art In blood analyzers and testing devices for genetic tests and drug discovery tests, it is desired to reduce the minimum discharge amount of a liquid discharge system in order to reduce running costs and improve throughput. . Conventionally, in such an inspection apparatus, a syringe piston pump has been used as a liquid discharging means. However, the minimum discharge amount of the syringe piston pump is about 2 μL, and if a small amount of liquid is discharged more than about 2 μL. In addition, there is a problem that the ejection accuracy is significantly deteriorated. To cope with this problem, a microfluidic processing apparatus equipped with a microdispenser to which a piezoelectric transducer is applied, described in Japanese Patent Application Laid-Open No. H10-114394, has a discontinuous and substantially reproducible 1 nL.
The ejection amount is controlled so as to form a droplet having a size of less than. Hereinafter, the schematic configuration will be described with reference to FIGS.

[0003] The microfluidic processing apparatus 210 shown in FIG.
Piezoelectric transducer 260 attached to glass capillary 262
And a microdispenser 216 that fills the microdispenser 216 with a transfer fluid 224, aspirates the transfer fluid 224 from the microdispenser 216, controls the pressure of the system fluid 220, and controls the microdispenser 216 between transfers. It comprises a positive displacement pump 212 for cleaning and a piezoresistive pressure sensor 214 for measuring the pressure of the system fluid 220 and for generating a corresponding electrical signal. This piezoresistive pressure sensor 2
The pressure signal measured by 14 is used to check and measure the volume of dispensed transfer fluid 224 and to perform automated adjustment and diagnostics of microdispenser 216. That is, an electrical signal corresponding to the pressure measured by the piezoresistive pressure sensor 214 is sent to a control circuit, which receives the electrical signal, converts the electrical signal into a digital form and distributes the electrical signal to a corresponding portion of the dispensed fluid 224. Generates an indication of volume. This conventional microfluidic processing apparatus is configured to inspect a very small amount of fluid distributed during real-time operation.

[0004] The micro dispenser 216 is shown in FIG.
As shown in FIG. 3, it comprises a glass capillary tube 262 and a piezoelectric ceramic tube 260 connected thereto. The piezoelectric ceramic tube 260 includes an inner electrode 266 and an outer electrode 268 for receiving an analog voltage pulse for contracting the piezoelectric ceramic tube 260, and receives the analog voltage pulse when ejecting a liquid. Shrink, and after this shrinkage, the glass capillary 262 is deformed. This deformation of the glass capillary 262 creates a pressure wave that travels within the transfer fluid 224 and reaches the nozzle 263 of the microdispenser 216, so that at the nozzle 263, one droplet 226 of the transfer fluid 224 has a very high acceleration. Be injected. This conventional example shows an example in which a 5-picoliter droplet 226 is ejected.

[0005]

In general, in order to discharge droplets on the order of picoliters with high precision in a liquid dispensing apparatus, it is desirable to keep the nozzle end face as clean as possible. If foreign matter or liquid is attached to the nozzle end surface, it may cause a deterioration in ejection accuracy. However, when the test sample is sucked into the micro-dispenser 216,
Since the nozzle 263 is suctioned by being brought into contact with the surface of the test sample, the test sample may adhere to the nozzle end surface. If the liquid adheres to the nozzle end surface, the liquid is ejected from the nozzle 263 in the subsequent ejection process. The droplets come into contact with the liquid adhering to the nozzle end surface, and are affected by the surface tension and the viscous resistance of the liquid, resulting in a problem that the ejection accuracy is deteriorated. Therefore, the above conventional example cannot avoid the problem that the liquid attached to the nozzle end surface at the time of suction deteriorates the discharge accuracy.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid dispensing apparatus and a liquid dispensing method which improve the discharge accuracy by preventing the liquid from adhering to a discharge port of a liquid holding member.

[0007]

According to a first aspect of the present invention, there is provided a liquid holding member for holding a liquid therein, and a suction means for sucking the liquid into the liquid holding member. A liquid dispensing apparatus, comprising: a driving unit for generating a discharge pressure for discharging the liquid held in the liquid holding member, wherein a minute amount of liquid is discharged from a discharge port of the liquid holding member. Wherein the suction means has a control means for sucking the liquid adhering to the end face of the discharge port into the liquid holding member when the liquid suction operation is completed.

According to a second aspect of the present invention, a liquid holding member for holding a liquid therein is provided.
A liquid dispensing apparatus, comprising: a driving unit for generating a discharge pressure for discharging the liquid held in the liquid holding member, wherein a minute amount of liquid is discharged from a discharge port of the liquid holding member. The end face of the discharge port is constituted by a peripheral portion of the discharge port and an outer peripheral portion having a relatively higher surface energy than the peripheral portion of the discharge port, so that the surface state is such that liquid does not adhere to the peripheral portion of the discharge port. It is characterized by comprising.

According to a third aspect of the present invention, in order to achieve the above object, a discharge pressure is generated in a liquid held inside a liquid holding member, and a minute amount of liquid is discharged from a discharge port of the liquid holding member. A liquid dispensing method for discharging a liquid, wherein a first suction step of suctioning the liquid to be discharged from the discharge port into the liquid holding member while the discharge port of the liquid holding member is immersed in the liquid, A second suction step of sucking the liquid adhering to the end face of the discharge port into the liquid holding member while the discharge port is retracted from the liquid after the first suction step. It is characterized by the following.

According to a fourth aspect of the present invention, in the second suction step, suction is performed until the meniscus of the discharge port is retracted into the liquid holding member.

[0011]

According to the first invention, the suction means for sucking the liquid into the liquid holding member removes the liquid attached to the end face of the discharge port of the liquid holding member after the completion of the liquid suction operation. Since there is a control means for sucking the liquid inside, the liquid adhering to the end face of the discharge port is sucked and removed into the liquid holding member. Therefore, when the liquid in the liquid holding member is discharged from the discharge port with the discharge pressure generated by the driving unit, the liquid is discharged in a state where the liquid does not adhere to the discharge port end face, Discharge accuracy can be improved.

According to the second aspect, the end face of the discharge port of the liquid holding member for holding the liquid inside is formed by the peripheral portion of the discharge port and the outer peripheral portion having higher surface energy than the peripheral portion of the discharge port. The liquid attached to the peripheral portion of the discharge port on the end face of the discharge port is relatively more liquid than the peripheral portion of the discharge port, since the liquid is configured to have a surface state in which the liquid does not adhere to the peripheral portion of the discharge port. It moves to the outer peripheral portion located on the outer side where the surface energy is high. Therefore, since the liquid does not adhere to the periphery of the discharge port, the discharge accuracy can be improved.

According to the third invention, the liquid adhering to the end face of the discharge port is sucked and removed into the liquid holding member by the second suction step. Therefore, when the liquid in the liquid holding member is discharged from the discharge port, the liquid is discharged in a state where the liquid does not adhere to the end face of the discharge port, so that the discharge accuracy can be improved. Further, according to the fourth aspect, since the meniscus of the discharge port is sucked until the meniscus retreats into the liquid holding member, the discharge accuracy can be reliably improved.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a view showing a schematic configuration of a liquid dispensing apparatus according to a first embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view of the liquid ejection head of the embodiment, and FIG.
FIG. 4 is a diagram for explaining a liquid attached state when a test sample suction operation is completed by the liquid discharge head according to the embodiment. FIG. 4 illustrates a liquid suction operation after completion of the test sample suction operation by the liquid discharge head according to the first embodiment. FIG. 5 is a view showing a state after the completion of the suction operation shown in FIG. 4 of the first embodiment, and FIGS. 6A to 6E show the liquid discharge head of the first embodiment. FIG. 7 is a diagram for explaining a test sample discharge operation, and FIG. 7 is a diagram illustrating a drive voltage waveform of a laminated piezoelectric element of the liquid discharge head according to the first embodiment.

First, a schematic configuration of the liquid dispensing apparatus of the present embodiment will be described with reference to FIG. The liquid ejection head 20 of the liquid dispensing apparatus of the present embodiment is supported by a movable transport member (not shown), and is moved and arranged above the test sample container 21, the cleaning tank 22, and the reaction container 23, respectively. I have. One end of the liquid discharge head 20 is connected to a syringe piston pump 27 by a Teflon (registered trademark) pipe 25. The syringe piston pump 27 has a Teflon pipe 25 and a pipe 26 leading to a liquid supply tank 28.
Is connected, and the pipe 26 is sequentially connected to a liquid supply tank 28 via an electromagnetic valve 29 and a water supply pump 30.

The piston of the syringe piston pump 27 is driven by a linear reciprocating actuator including a stepping motor and a gear rack pinion (not shown) so as to reciprocate in the direction shown by the arrow in the figure. The liquid discharge head 20 and the syringe piston pump 27
And the liquid supply tank 28 are installed at approximately the same height. The liquid supply tank 28 contains water serving as washing water or degassed ion-exchanged water. By driving a water supply pump 30, the pipe 26, the syringe piston pump 27, the pipe 25, and the liquid discharge head 20
Is supplied with cleaning water.

As shown in FIG. 2, the liquid discharge head 20 includes a flow path member 34 serving as a liquid holding member and a flow path member 3.
4 for driving the piezoelectric element 4. One end (upper end in the figure) of the laminated piezoelectric element 32 in the displacement direction is a
, And the other end (the lower end in the figure) is fixed to the flow path member 34. As shown in FIG. 2, a flow path 35 for holding a liquid and an inlet 36 for introducing a liquid into the flow path 35 are formed inside the flow path member 34. The channel 35 includes a straight portion 37 and a tapered portion 38 and communicates with the outside atmosphere at an opening 39. The approximate dimensions of the straight part 37 are as follows: flow path width 0.5 mm to 3 mm, length 3 mm to 2
0 mm. The tapered portion 38 is formed from the lower end of the straight portion 37 toward the opening 39, and the size of the opening 39 is 50 μm to 100 μm in opening width.

Since the space between the laminated piezoelectric element 32 and the flow path 35 is formed as a rigid body, the flow path member 34 is vertically displaced in the figure by the displacement of the laminated piezoelectric element 32. Further, a voltage of a desired waveform is applied to the laminated piezoelectric element 32 from a drive circuit (not shown) by a lead wire or a flexible substrate. Further, in order to prevent dust in the air from adhering to the vicinity of the opening 39 due to the charging of the liquid ejection head 20, it is configured so that static electricity can be removed by blowing ionized air from a blower (not shown).

Next, various operations of the liquid dispensing apparatus of the present embodiment will be described. First, for the cleaning operation, the liquid discharge head 20 is moved above the cleaning tank 22, and then the tip of the liquid discharge head 20 is immersed in the cleaning tank 22.
Next, after opening the electromagnetic valve 29, the water pump 30 is driven to send the cleaning water in the liquid supply tank 28 to the flow path 35 of the liquid ejection head 20. As a result, the inner peripheral surface of the flow channel 35, the outer peripheral surface and the lower end surface of the distal end of the flow channel member 34 are washed with the washing water.

After the syringe piston pump 27 is moved to the middle of the stroke during the supply of the washing water, the electromagnetic valve 29 is closed to fill the inside of the flow path 35 with the washing water. Next, the liquid discharge head 20 is raised and the cleaning tank 2 is moved.
2 above, where ionized air is blown from a blower (not shown). Thereby, the liquid discharge head 2
0 means that the charge is removed and the dust is removed.

Next, the syringe piston pump 27 is moved downward by a predetermined amount, and a predetermined amount of air is
Suction into 5. Thereafter, the liquid discharge head 20 is moved above the test sample container 21 so that the tip of the liquid discharge head 20 is 1 mm to 2 mm in the test sample of the test sample container 21.
Let it soak. Thereafter, the test sample is sucked into the flow path 35 by moving the piston of the syringe piston pump 27 downward by a predetermined amount. At that time, the cleaning water and the test sample in the flow path 35 are separated by an air layer.

After a predetermined amount of the test sample is sucked as described above, the liquid discharge head 20 is raised and moved above the test sample container 21. At this time, since the liquid (in this case, the test sample) is attached to the end face of the opening 39 as shown in FIG. 3, the piston of the syringe piston pump 27 is moved downward to remove the test sample. Then, the adhering test sample is sucked from the opening 39 into the channel 35 as shown by the arrow in FIG. At this time, the syringe piston pump 27 functions as a control unit that sucks the liquid attached to the end face of the opening 39 into the liquid ejection head 20. Thereafter, after moving the liquid discharge head 20 above the reaction container 23, the test sample is discharged into the reaction container 23.

FIG. 5 shows a state after the liquid adhering to the end face of the opening 39 is sucked into the liquid discharge head. In this way, by setting the meniscus in the opening 39 to retreat into the flow path 35, the ejection accuracy can be reliably improved. At this time, the retreat amount X is obtained by setting the diameter of the opening 39 to D (m
m), it is preferable that 0.2D <X <3D.

Next, the operation of discharging the test sample will be described. While a drive voltage having a waveform as shown in FIG. 7 is applied to the laminated piezoelectric element 32 of the liquid ejection head 20, t in FIG.
Assuming that the vertical position of the tip of the liquid discharge head 20 at the time t <b> 1 and the voltage E = E <b> 0 is A, t <b> 1 in FIG.
As the voltage gradually rises at t <t2, the liquid discharge head 20 is slowly displaced downward in the figure, and
Immediately before t = t2 in (c), a displacement corresponding to the voltage E1 occurs in the laminated piezoelectric element 32, and the displacement causes the tip of the liquid ejection head 20 to descend to the position B.

Thereafter, at t = t2 in FIG. 6D, the voltage E instantaneously decreases to E0. As the voltage E suddenly decreases, the liquid discharge head 20 changes from falling to rising, and suddenly moves upward in the drawing. During the forward / backward movement of the liquid ejection head 20 along the ejection direction, when the leading end of the channel member 34 of the descending liquid ejection head 20 stops at the position B, inertia is applied to the test sample in the channel 35. When the force acts, the flow path 3
The test sample in 5 moves simultaneously and instantaneously downward in the figure, and a flow of the test sample in the downward direction in the figure occurs. Due to the flow of the test sample, the pressure at the distal end of the tapered portion 38 rises, breaking the surface tension at the opening 39 and discharging the test sample droplet to the outside.

At this time, the liquid (in this case, the test sample) adhering to the end face of the opening 39 is suctioned and removed into the flow passage 35 in advance by the downward movement of the piston of the syringe piston pump 27 in the suction step. Therefore, the discharged test sample is discharged without coming into contact with another liquid. In this case, the amount of the test sample discharged from the liquid discharge head 20 depends on the taper angle of the tapered portion 38 and the opening 3.
9, the amount is in the range of about 0.01 nL to 0.3 nL in the present embodiment. Thereafter, at t> t2 in FIG. 6E, the liquid ejection head 20 returns to the initial position.

After the desired amount of the test sample is discharged as described above, the liquid discharge head 20 is moved again above the cleaning tank 22, and the cleaning water is supplied to the flow path 35 and The remaining test sample is discharged, and the flow path 35 is discharged.
And the outer peripheral surface at the tip of the flow path member 34 are cleaned.
Thereafter, by repeating a series of steps from the above-described cleaning step to the discharging step, a desired amount of the test sample is supplied to the reaction vessel 2.
3 will be discharged.

According to the present embodiment, the test sample attached to the end face of the opening 39 of the liquid ejection head 20 in the test sample suction step flows by the downward movement of the piston of the syringe piston pump 27 again after the liquid suction operation is completed. Since the sample is suctioned and removed in the passage 35, the test sample discharged from the opening 39 does not come into contact with another liquid, and the discharge accuracy can be improved.

In this embodiment, a liquid discharge head of an inertial force discharge type which discharges liquid by an inertial force when the flow path member is reciprocated in the discharge direction is used as the liquid discharge head. For example, as shown in FIG. 8, similarly to the above-described conventional example, the cylindrical piezoelectric ceramics 42 are contracted in the radial direction to form the flow path member 3.
A liquid ejecting head of the principle of ejecting liquid by changing the volume of the ink jet head 4 (ink jet type liquid ejecting head) may be used.

FIG. 9 is a sectional view of a liquid discharge head according to a second embodiment of the present invention, FIG. 10 is an enlarged view of the vicinity of the opening of the liquid discharge head of the second embodiment, and FIG. 11 is a second embodiment. FIG. 7 is a diagram for explaining a state of liquid attachment to the opening when the test sample suction operation by the liquid discharge head is completed. This embodiment is different from the first embodiment in that the liquid ejection head 20
The configuration of the end face of the opening 39 of the flow path member 34 is changed, and the other portions are configured in the same manner as in the first embodiment. .

As shown in FIG. 10, a thin film 41 of SiO ₂ is formed on the outer peripheral portion of the end face of the opening 39 of the liquid discharge head 20 in this embodiment at a slight distance from the opening 39.
Are formed, and SiO ₂ has a high surface energy and has a property of being well wetted by a liquid. On the other hand, opening 3
9 is formed of a metal such as stainless steel having a lower surface energy than SiO ₂ ,
Metals such as stainless steel have a property that they are less likely to be wet by liquids than SiO ₂ . Therefore, since the peripheral portion 40 of the opening 39 is a surface made of a metal such as stainless steel, the peripheral portion 41 is hardly wet by the liquid.
_{Since the two} films are formed, they have surface characteristics that are easily wetted by a liquid. The contact angle of stainless steel with water in the atmosphere is about 60 °, and the opening 39 and the outer peripheral portion 4
The distance between the first SiO ₂ film is a schematic 30μm~100
μm.

Next, various operations of the liquid dispensing apparatus of the present embodiment will be described. First, after cleaning the flow channel 35 by the same cleaning process as in the first embodiment, a predetermined amount of air is sucked into the flow channel 35, and then the liquid ejection head 20 is placed in the test sample in the test sample container 21. By immersing the distal end portion by 1 mm to 2 mm and moving the piston of the syringe piston pump 27 downward by a predetermined amount, a predetermined amount of the test sample is sucked into the channel 35. Thereafter, the liquid discharge head 20 is raised above the test sample container 21.

At this time, a test sample is placed on the end face of the opening 39.
Although it adheres, the test sample extends over the entire end face of the opening 39.
It does not adhere, and as shown in FIG.₂
It adheres only to the outer peripheral portion 41 where the film is formed, and the opening 39
Does not adhere to the peripheral portion 40 of. The reason is that the opening 39
SiO having a higher surface energy than the peripheral portion 40 of the end face
₂This is because the test sample is pulled on the film area. But
Therefore, make sure that no test sample is attached around the opening.
A test sample can be aspirated. After that,
The head 20 is moved above the reaction vessel 23, and
In the same manner as in the embodiment, a desired amount of
The test sample will be discharged.

According to the present embodiment, the test sample attached to the end face of the opening 39 when the test sample is sucked is moved from the peripheral portion 40 of the end face of the opening 39 to the SiO ₂ film region of the outer peripheral portion having higher surface energy. Therefore, the test sample does not remain attached to the periphery of the opening 39. Therefore, the ejection accuracy can be improved.

Further, according to the present embodiment, the end face of the opening 39 of the flow path member 34 of the liquid discharge head 20 is simply made to have the above-described surface configuration including the peripheral portion 40 and the outer peripheral portion 41, and the opening 39 Since the movement of the adhered liquid at the end face is performed autonomously based on the difference in surface energy, a new process or operation for removing the adhered liquid is not required, and the dispensing operation time is shortened.

In this embodiment, the liquid is prevented from adhering to the peripheral portion 40 at the end face of the opening 39 by forming the SiO ₂ film.
Even if the surface energy is reduced by applying a fluorine-based material to 0, for example, the same effect as described above can be obtained. In short, if the surface energy of the outer peripheral portion 41 is relatively higher than the surface energy of the peripheral portion 40, the liquid attached to the end face of the opening 39 moves to the outer peripheral portion 41 having a higher surface energy. , Peripheral part 40
Can be prevented from adhering to the liquid. According to an experiment by the inventor of the present application, it has been confirmed that if there is a difference of about 20 degrees or more in the contact angle with water, the liquid attached to the end face moves to the outer peripheral portion 41.

In this embodiment, the SiO ₂ film is formed on the outer peripheral portion 41 of the end face of the opening 39. However, the same effect can be obtained by using a titanium oxide film. further,
In the present embodiment, as the liquid discharge head, a liquid discharge head of an inertial force discharge type that discharges liquid by an inertial force when the flow path member is reciprocated in the discharge direction is used, but is not limited thereto. Instead, for example, as shown in FIG. 8, similar to the above-described conventional example, the principle is that the liquid is ejected by changing the volume of the flow path member 34 by contracting the cylindrical piezoelectric ceramics 42 in the radial direction. Liquid ejection head).

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a liquid dispensing apparatus according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the liquid ejection head according to the first embodiment.

FIG. 3 is a diagram for explaining a liquid adhering state at the completion of an inspection sample suction operation by the liquid ejection head according to the first embodiment.

FIG. 4 is a diagram for explaining a liquid suction operation after a test sample suction operation by the liquid discharge head according to the first embodiment is completed.

FIG. 5 is a diagram illustrating a state after completion of the suction operation illustrated in FIG. 4 of the first embodiment.

FIGS. 6A to 6E are views for explaining a test sample discharging operation by the liquid discharge head according to the first embodiment.

FIG. 7 is a diagram illustrating a drive voltage waveform of a laminated piezoelectric element of the liquid ejection head according to the first embodiment.

FIG. 8 is a view showing a modification of the liquid ejection head of the first embodiment.

FIG. 9 is a sectional view of a liquid ejection head according to a second embodiment of the present invention.

FIG. 10 is an enlarged view of the vicinity of an opening of a liquid ejection head according to a second embodiment.

FIG. 11 is a view for explaining a state in which a liquid is attached to an opening when a test sample suction operation is completed by a liquid discharge head according to a second embodiment.

FIG. 12 is a diagram illustrating a configuration of a conventional liquid ejection head.

FIG. 13 is a diagram illustrating a configuration of a conventional liquid ejection head.

[Explanation of symbols]

 Reference Signs List 20 liquid discharge head 21 test sample container 22 cleaning tank 23 reaction container 25 Teflon pipe 26 pipe 27 syringe piston pump 28 liquid supply tank 29 electromagnetic valve 30 water supply pump 32 laminated piezoelectric element 33 gantry 34 flow path member 35 flow path 36 inlet 37 Straight part 38 Taper part 39 Opening

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Imabayashi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Industrial Co., Ltd. (72) Inventor Takami Shibasaki 2-43 Hatagaya, Shibuya-ku, Tokyo No. 2 F-term in Olympus Optical Co., Ltd. (reference) 2G058 EA11 EB01 EB21 ED22 ED26 ED33 FB06 FB25 GB04

Claims (4)

[Claims] 1. A liquid holding member for holding a liquid therein,
A suction unit that sucks the liquid into the liquid holding member; and a driving unit that generates a discharge pressure for discharging the liquid held in the liquid holding member. A liquid dispensing device configured to discharge the liquid, wherein the suction means has a control means for suctioning the liquid attached to the end face of the discharge port into the liquid holding member after the liquid suction operation is completed. A liquid dispensing device characterized by the above-mentioned. 2. A liquid holding member for holding a liquid therein,
A liquid dispensing apparatus, comprising: a driving unit for generating a discharge pressure for discharging the liquid held in the liquid holding member, wherein a minute amount of liquid is discharged from a discharge port of the liquid holding member. The end surface of the discharge port is formed of a peripheral portion of the discharge port and an outer peripheral portion having a relatively higher surface energy than the peripheral portion of the discharge port, so that the surface state is such that liquid does not adhere to the peripheral portion of the discharge port. A liquid dispensing device, characterized in that: 3. A liquid dispensing method in which a discharge pressure is generated in a liquid held inside a liquid holding member to discharge a minute amount of liquid from a discharge port of the liquid holding member. With the discharge port immersed in the liquid,
A first suction step of sucking the liquid to be discharged from the discharge port into the liquid holding member; and an end face of the discharge port in a state where the discharge port is retracted from the liquid after the first suction step. A second suction step of sucking the liquid adhering to the liquid holding member into the liquid holding member. 4. The liquid dispensing method according to claim 3, wherein in the second suction step, suction is performed until the meniscus of the discharge port is retracted into the liquid holding member.