JPH09126136A - Method of discharging fluid and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge device suitable for high viscous liquid, for delivering a trace volume of liquid with a high degree of accuracy. SOLUTION: A laminated piezoelectric element 14 is driven in response to a drive signal S3 having a moderate rise-up and delivered from a controller 40 when receiving a signal S1, and accordingly, increases its length, rapidly, and then restores its length, moderately. In association with this motion, a thin plate 12 rapidly flexes so that oil 17 filled in a liquid chamber 11a is abruptly compressed, and accordingly, a negative pressure wave is transmitted from a discharge port, following a positive pressure wave. As a result, the liquid surface bulges so that the oil 17 is formed into a liquid drop 25 which is detected by a discharge detecting sensor 34. When the thin plate 12 restores its original shape, the liquid chamber 11 is replenished with oil 17 by a quantity corresponding to the volume of the discharged oil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid ejecting method, and more particularly to a liquid ejecting method suitable for ejecting a minute amount of a highly viscous liquid and an apparatus therefor.

[0002]

2. Description of the Related Art As a conventional method for quantitatively discharging a liquid, a liquid stored in a syringe is compressed with air pressure for a predetermined time,
There is a method using a so-called dispenser that drops or pushes out from the tip of an injection needle, a method that uses a so-called syringe-type ejector that pushes out a liquid that has been sucked into a cylinder with a certain amount by a piston, or a method in which the droplets fall freely at that time. . Each of these liquid discharging methods is such that when the minimum supply amount is increased to some extent and the accuracy of the amount is rough, for example, when a minute amount of liquid is discharged such as when refueling a timepiece movement. It is not suitable.

On the other hand, as a conventional method of refueling a timepiece movement, a transfer type refueling method of picking up a certain amount of oil from an oil tank with a refueling needle and transferring it to a refueling point and transferring the refueling needle from the oil tank is built in. There is a bell jon type refueling method in which a certain amount of oil is sucked up by the refueling pipe and brought into proximity with or in contact with a refueling point, and then a refueling needle is ejected to refuel.

One of the conventional timepiece oil supply methods will be described below with reference to the drawings. FIG. 13 is an explanatory diagram showing the operation of the bell jon type refueling method. In FIG. 13, reference numeral 81 is a nozzle that is the tip of the oil supply device, and 82 is an oil supply needle that slides in and out of the nozzle 81. Reference numeral 83 is the timepiece oil that is replenished in the oil tank, and 84 is an oil-supplied location on the timepiece component. In this refueling method, first, as shown in (a), the nozzle 81 of the refueling machine is held so as to enter a predetermined depth from the oil 83 surface,
After the refueling needle 82 is immersed in the oil 83, the refueling needle 82 is retracted by a predetermined amount as shown in (b), and then the refueling device is separated from the oil 83 surface as shown in (c), (d). As shown in (e), after the tip of the nozzle 81 is moved and brought close to the oil-supplied portion 84, the refueling needle 82 is projected to push the abutting oil 83 to the oil-supplied portion 84, and then (f )
As shown in FIG. 7, the nozzle 81 is pulled up while the refueling needle 82 is left out.

[0005]

However, in the case of such a conventional oil supply method, the influence of the depth at which the tip of the nozzle 81 enters the oil 83 of the oil tank, the speed at the time of leaving the surface of the oil 83, and the like are affected. Upon receipt, the amount of oil 83 retained in the nozzle 81 at the stage of FIG. 13C changes. Also,
When the tip end of the nozzle 81 and the oil-supplied location 84 are once connected via the oil 83 as shown in (e), the nozzle 81 is separated from the oil-supplied location 84 as shown in (f). A little oil 83 remains on the 81 side as well, but the remaining amount is not constant due to the separation speed of the nozzle 81. Further, it is difficult to control the amount of refueling with high accuracy due to the influence of the surface condition of the portion to be refueled. In addition, since a minute nozzle or needle tip may come into contact with the part to be lubricated, there is a difficulty in the durability of the lubricator.
Further, depending on the material of the lubricated portion, the lubricated portion may be damaged. Further, when this method is applied to an automatic assembly line, it is difficult to detect a refueling error at the time of refueling, and an oil presence / absence test in a post process is indispensable.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional liquid discharge method and to provide a liquid discharge method and apparatus suitable for discharging a very small amount of high viscosity liquid.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 of the present invention is a method for discharging a liquid, comprising a supply tank for supplying the liquid, and a liquid filled with the liquid. A chamber and a nozzle for ejecting liquid from the liquid chamber,
An elastic plate forming a part of the liquid chamber, a piezoelectric element arranged so that one end abuts on the elastic plate, and a drive circuit for driving the piezoelectric element, and supplies liquid to the liquid chamber. And a step of driving the piezoelectric element by a drive signal from the drive circuit to discharge the liquid filling the liquid chamber from the tip of the nozzle into droplets.

According to a second aspect of the present invention, in the configuration of the first aspect of the invention, the drive circuit generates a pulse waveform which is the drive signal, and a waveform which shapes the pulse waveform. A control circuit is provided, and the fall of the pulse waveform is moderated by the time constant of the waveform control circuit.

According to a third aspect of the invention, in the configuration of the second aspect of the invention, the supply tank and the liquid chamber are connected by a supply pipe, and the liquid level of the supply tank is from the tip of the nozzle. It is characterized in that it is arranged so as to be low.

The invention according to claim 4 is characterized in that, in the constitution of the invention according to claim 1, the viscosity of the liquid is controlled by adjusting the temperature of the liquid.

According to a fifth aspect of the present invention, in the configuration of the second aspect of the invention, there is provided detection means for detecting the temperature of the liquid, and the drive signal is driven according to the detection result of the detection means. It is characterized by adjusting the voltage.

According to a sixth aspect of the invention, there is provided a discharge presence / absence detection sensor for detecting the discharged droplets in the configuration of the first aspect of the invention.

According to a seventh aspect of the present invention, in the constitution of the first aspect of the invention, the liquid chamber is provided with a means for collecting the liquid, and the liquid is filled in the liquid chamber and the liquid at the nozzle discharge port is filled. It is characterized by having an automatic initialization function for adjusting the surface.

The invention described in claim 8 is characterized in that, in the constitution of the invention described in claim 1, the liquid is watch oil, and the invention is applied to watch assembly.

According to a ninth aspect of the invention, there is provided a liquid ejecting apparatus, wherein a supply tank for supplying the liquid, a liquid chamber filled with the liquid, a nozzle for ejecting the liquid from the liquid chamber, and the liquid chamber. An elastic plate forming a part of the piezoelectric element, a piezoelectric element arranged so that one end thereof abuts on the elastic plate, and a drive circuit for driving the piezoelectric element. The piezoelectric element is driven by a drive signal from the drive circuit. The liquid filled in the liquid chamber is discharged as droplets from the tip of the nozzle by driving the element.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. 1 is an explanatory view showing a refueling process when the present invention is applied to a watch assembly line, FIG. 2 is an explanatory view showing a configuration of the refueling device of FIG. 1, and FIG. 3 is a cross section showing a main part of the refueling device of FIG. It is a figure.

First, the structure of the oil supply process of the timepiece assembly line will be described. In FIG. 1, 1 is one of the conveyor legs connected to the watch assembly line, and 2 is this conveyor leg 1.
A leg controller 3 for controlling the leg controller 3 is a leg operation panel for operating the leg controller 2, and the leg operation panel 3 is provided with an error display lamp 3a and an error release switch 3b. 4
Is a timepiece module, and 5 is a carrier on which the timepiece module 4 is mounted, which is conveyed on the belt of the conveyor leg 1.
At a work station on the conveyor leg 1, a work unit (not shown) for pushing up the carrier 5 from above the belt is installed. Reference numeral 10 is a fueling device installed corresponding to one of the work stations, and is a clock module 4
It is for refueling watch oil. Reference numeral 11 is a main body of the oil supply device 10, 16 is a supply tank for supplying oil to the main body 11, and 22 is a recovery tank for recovering oil from the main body 11. Reference numeral 30 is a temperature adjuster for adjusting the temperature of the liquid, and 40 is a controller which is a drive circuit for driving the oil supply device 10.

Next, the surroundings of the main body of the oil supply device 10 will be further described. 2 and 3, a liquid chamber 11a for storing a cylindrical liquid is formed in the center of the upper portion of the main body 11, and a discharge pipe line 11b leading from below the liquid chamber 11a to a nozzle described later and a main body. 11 two supply ports 1 opened on the side
A supply line 11d leading to 1c is formed. Each supply conduit 11d communicates with the liquid chamber 11a from a point-symmetrical position on the outer periphery of the liquid chamber 11a, and when the liquid is supplied, the liquid chamber 1a
It is designed so that no bubbles are generated in 1a.
Reference numeral 12 is a thin plate which is an elastic plate adhered to the upper surface of the main body 11 so as to cover the liquid chamber 11a in a liquid-tight manner, and 13 is a housing which is connected to the main body 11 with the thin plate 12 interposed therebetween. Reference numeral 14 denotes a laminated piezoelectric element whose rear end is fixed to the housing 13 so that its front end contacts the thin plate 12. Reference numeral 15 is a nozzle for ejecting a liquid, which is detachably coupled to the lower portion of the main body 11 and is appropriately exchanged for use. A through hole 15 communicating with the discharge conduit 11b of the main body 11 is formed in the center of the nozzle 15.
a is formed, and the opening on the lower surface is the liquid discharge port 15
b.

Reference numeral 17 is a watch oil which is a liquid having a relatively high viscosity. 18 is oil 17 from the supply tank 16 to the main body 11.
Is a supply tube for sending the water, one end of which is the supply tank 16
Is submerged in the oil 17, and the other end is branched from the middle and is connected to two supply ports 11c leading to the liquid chamber 11a. Reference numeral 19 is a tube leading from a space in the supply tank 16 to a compressor (not shown), and 31 is a tube 19
This is the solenoid valve 1 for connecting and disconnecting the pipeline that is connected midway. 20
Is a tube that communicates with a vacuum pump (not shown) from the space inside the supply tank 16, and 32 is a solenoid valve 2 for connecting and disconnecting the pipeline, which is connected in the middle of the tube 20.

Reference numeral 21 denotes a recovery cap for liquid recovery, which is liquid-tightly attached to the main body 11 so as to cover the nozzle 15, and has an opening 21 in the liquid discharge direction below the discharge port 15b.
a, and a recovery port 21b is formed on the side surface. There is a slight space 21c between the nozzle 15 and the recovery cap 21. 23 is a recovery cap 21 to a recovery tank 2
2 is a collection tube for collecting a liquid that leads to 2. Reference numeral 24 is a tube leading from a space in the recovery tank 22 to a vacuum pump (not shown), and 33 is a solenoid valve 3 for connecting and disconnecting the pipeline, which is connected in the middle of the tube 24. These collection cap 21, collection tube 23, tube 24, solenoid valves 3, 3
3 and the recovery tank 22 constitute a liquid recovery means.

Reference numeral 25 is a droplet of the oil 17 discharged from the nozzle 15, and 34 is a reflection type which is installed in the vicinity of the opening 21a of the recovery cap 21 in order to detect the droplet 25 in the liquid discharging direction. It is a discharge detection sensor. 35 is oil 1
A heater for heating 7 and a temperature sensor 36 for detecting the temperature of the oil 17 are both installed near the liquid chamber 11a of the main body 11. The heater 35, the temperature sensor 36, and the temperature controller 30 are electrically connected to each other, and the power of the heater 35 is turned on / off according to the output detected by the temperature sensor 36. The controller 40 is electrically connected to each of the leg controller 2, the discharge detection sensor 34, the electromagnetic valves 1 to 3, 31 to 33, the piezoelectric element 14, and a refueling operation panel described later.

The distance h from the lower surface of the nozzle 15 to the oil level of the supply tank 16 shown in FIG. 3 is called the head difference. In this oil supply device 10, the oil surface of the supply tank 16 is installed so as to be below the lower surface of the nozzle 15, that is, there is a negative head difference. For this reason, the oil level at the discharge port 15a of the nozzle 15 is stable, and even if the work is stopped for a long time, no oil pool will occur near the discharge port 15b. For example, when the viscosity of the liquid is 30 to 270 cp, the liquid level is -2.
The supply tank 16 may be installed so as to be in the range of 0 mm <h <−30 mm. If it is out of this range, the following problems occur. That is, when 0 mm <h, the oil 17 drips down to the surface of the discharge port 15a even in a static state. Further, when -20 mm <h <0 mm, the oil 17 overflows from the discharge port 15b at the time of discharge and the oil 17 is discharged.
It may remain on the surface 5a. When h <-30 mm, the balance of the negative pressure due to the surface tension of the oil 17 and the water head difference is lost, the liquid surface is drawn into the through hole 15a, and bubbles enter.

Next, the structure of the drive circuit of the oil supply device 10 will be described. FIG. 4 is a circuit block diagram showing the configuration of the drive circuit,
FIG. 5 is a signal waveform diagram showing the waveform of the drive signal. In FIG. 4, reference numeral 41 is a control circuit including a CPU, a ROM, an I / O unit and the like. 42 is a refueling operation panel for operating the refueling device 10, 43 is A / D conversion of the output signal of the discharge sensor 34 and the detection signal S4 to the control circuit 41.
Is an amplifier unit that outputs. Amplifier unit 43
Is the leg controller 2, refueling operation panel 42, solenoid valves 1 to 3,
31 to 33 are connected to the I / O unit in the control circuit 41.

Reference numeral 44 is a drive signal S3 which is a pulse waveform signal to which the oil supply signal S2 output from the control circuit 41 is input.
It is a waveform generation circuit for generating. Reference numeral 45 is an amplifier circuit for amplifying the drive signal S3 output from the waveform generation circuit 44, and 46 is a variable DC power supply supplied to the amplifier circuit 45, which adjusts the strength of the drive signal S3. 4
Reference numeral 7 denotes a waveform control circuit for shaping the pulse waveform of the amplified drive signal S3, which has a time constant and is composed of a resistor and a capacitor. The waveform control circuit 47 is wired from the waveform control circuit 47 to the piezoelectric element 14. Reference numeral 48 is an external AC power supply, 49 is a DC control power supply that has been transformed and rectified from the external AC power supply 48,
It is supplied to the control circuit 41 and the waveform generation circuit 44.
The control circuit 41, the amplifier unit 43, the waveform generation circuit 44, the amplification circuit 45, the variable AC power supply 46, the waveform control circuit 47, and the control power supply 49 constitute the controller 40.

Next, the operation of this drive circuit will be described. With the above configuration, the CPU of the control circuit 41 is the refueling operation panel 42.
And the state of a carrier positioning completion signal S1 to be described later from the leg controller 2 and a detection signal S4 of the ejection sensor 34 output from the amplifier 43, and the solenoid valve according to the program stored in the ROM according to these states. The operation of 1-3, 31-33 is controlled, and the oil supply signal S2 which is an oil supply command is emitted. The drive signal S3 having a pulse waveform is generated from the waveform generation circuit 44 to which the oil supply signal S2 is input, and the drive signal S3 amplified by the amplifier circuit 45 is shaped by the waveform control circuit 47 and then drives the piezoelectric element 14.

Here, the drive signal S3 will be described. In FIG. 5, V is the maximum value of the drive voltage, and the drive signal S
Represents a strength of 3. The drive voltage V needs to be set according to the viscosity of the liquid used, and is set by adjusting a volume (not shown) installed in the variable DC power supply 46 of the controller 40. Further, T1 is a time that needs to be set in order to sufficiently increase the pressure of the liquid chamber 11a, which will be described later, with a sufficient margin. When the liquid discharge ends and the volume of the liquid chamber 11a returns to the initial state, the discharged oil 17 must be replenished into the liquid chamber 11a from the supply tank 16 side and the nozzle 15 side. When the value is high, the supply of the oil 17 from the supply tank 16 is gradual and insufficient, so that bubbles easily enter through the discharge port 15a of the nozzle 15.
T2 is the time required to prevent the invasion of the bubbles, and by setting this time T2, the fall of the pulse waveform is made gentle. These set values are, for example, V
= 30v, T1 = 10ms, T2 = 40ms. Since the piezoelectric element 14 is driven by the drive signal S3 having a pulse waveform with a gradual fall in this way, the length of the piezoelectric element 14 is rapidly extended and gradually increased according to the drive waveform each time the drive signal S3 is output. Repeat the action to restore the original.

Next, the operation of the oil 17 in the liquid chamber 11a caused by the operation of the piezoelectric element 14 will be described with reference to the drawings. FIG. 6 is a flowchart showing the operation steps of the oil 17 in the liquid chamber 11a, and FIG. 7 is a conceptual diagram showing the same operation steps. The piezoelectric element 14 is rapidly expanded by the drive voltage V of the drive signal S3 applied to the piezoelectric element 14 (FIG. 6).
As the thin plate 12 of the liquid chamber 11a bends (step n1) (step n2), the oil 17 in the liquid chamber 11a is rapidly compressed to increase the pressure (step n3), and the supply pipe line 11d and discharge are performed. The oil 17 inside the pipeline 11b is supplied to the supply tank 1
It is accelerated toward both ends of the No. 6 side and the nozzle 15 side (step n4, FIG. 7A), and the oil surface (meniscus) expands outward at the discharge port 15b (step n5, FIG. 7).
(B)).

Since the oil 17 in the discharge pipe line 11b has inertia, the movement of the oil 17 in the direction of the nozzle 15 does not occur in the liquid chamber 11a.
It works to make the internal pressure negative (step n6), and the oil 17 inside the discharge pipe line 11b decelerates (step n6).
7, FIG. 7 (c)). After that, the oil 1 inside the discharge line 11b
7 is accelerated in the direction of the liquid chamber 11a by the negative pressure inside the liquid chamber 11a, the oil 17 in the portion that bulges outside the discharge port 15b is cut off, and discharged as a droplet 25 (step n).
8, FIG. 7 (d). After that, when the driving voltage applied to the piezoelectric element 14 decreases, the piezoelectric element 14 returns to the original length,
Along with that, the bending of the thin plate 12 also returns to its original state (step n).
9). Then, the same amount of oil 17 as the volume of the discharged liquid droplets 25 is supplied from the nozzle 15 side and the supply tank 16 side to the discharge pipe line 11
The liquid chamber 11a is replenished through b and the supply conduit 11d (step n10).

At this time, the oil surface of the ejection port 15b after the ejection of the droplet 25 can prevent the air from being entrained in the through hole 15a to generate bubbles due to the effect of the above-mentioned signal waveform, so that a stable liquid can be obtained. It is possible to eject the droplet 25. The volume of each droplet 25 per shot changes depending on the size of the diameter of the ejection port 15b and can be selected within the range of about 0.001 to 0.01 mm ^3. However, if the droplet 25 is small, the detection reliability is high. If the droplets 25 decrease and the droplets 25 are too large, the minimum amount of oil supply at the oil-supplied location will be exceeded, and it is necessary to set the value within an appropriate range according to the required amount of oil supply. Main oil supply device 10
In the case of, the optimal discharge amount per droplet is 0.006
It is about 0.008 mm ³ . Further, when the amount of refueling differs depending on the location to be refueled, the amount of refueling can be set by the number of times the droplets 25 are ejected. Incidentally, the variation in the volume of the droplet 25 is about ± 20%.

Next, the control operation of the oil supply apparatus according to the present invention will be described with reference to the operation flowchart. FIG. 8 is a control operation flowchart of the conveyor leg of the watch assembly line, FIG. 9 is an initial refueling operation flowchart, FIG. 10 is a list showing the state of the refueling device, FIG. 11 is a refueling device control operation flowchart, and FIG. 12 is a bubble elimination control. It is an operation | movement flowchart.

First, the operation of the conveyor leg 1 of the assembly line will be described with reference to FIGS. In the initial state of the conveyor leg 1, the power of the leg controller 2 is turned on, the internal program is normally started, and the carrier 5 on which the clock module 4 is mounted is waiting to flow on the conveyor leg 1. Yes (step n21). When the carrier 5 flows into the work station of the refueling process, the leg controller 2
Is pushed up by a work unit (not shown), and the timepiece module 4 is set to the reference position (step n22). Then, the leg controller 2 issues a carrier positioning completion signal S1 to the fueling device 10 (step n23), and waits for the fueling completion signal S5 from the fueling device 10 (step n24). When the refueling completion signal S5 is not input, the process waits for the error signal S6 from the refueling device 10 to be input (step n25).

If the error signal S6 does not enter, step n
Returning to step 24, if the error signal S6 is input, error processing is performed (step n26). In the error processing, the error lamp 7a is turned on, and the work unit waits for the worker while suspending the operation while holding the carrier 5. Then, the operator confirms the error state, removes the cause, and presses the error release switch 7b. Then, the working unit releases the push-up of the carrier 5 (step n27) and returns it onto the belt, so that the worker removes the discharged carrier 5 from the belt. Meanwhile, the leg controller 2 returns to the initial state (step n21). Refueling device 1 in step 24
When the refueling completion signal S5 is input from 0, the thrust of the work unit is released (step 27) and the initial state is returned (step n21). Meanwhile, the carrier 5 on which the refueled timepiece module 4 is placed is conveyed to the next step on the belt.

Next, the operation of the oil supply device 10 will be described. The initial state of the refueling device 10 side is as follows. First, the liquid chamber 11a, the supply pipe line 11d, and the discharge pipe line 11b of the main body 11 are filled with the oil 17, and bubbles are not mixed therein. The surface of the ejection port 15b is clean and free of dust and the like. Furthermore,
The oil 17 is supplied to the refueling tank 16, and the head difference h between the tank oil surface and the discharge port 15b surface is appropriately adjusted as described above. Further, the temperature controller 30 is in a power-on state and the liquid chamber 11a is maintained at an appropriate temperature. The controller 40 of the refueling device 10 is in a power-on state,
The internal program starts up normally and the leg controller 2
It is in the state of waiting for the carrier positioning completion signal S1 from. Then, in the memory of the control circuit 41 of the refueling device controller 40, the number of retries n1 in the case of a discharge error, the number of discharges per refueling n2, the frequency of continuous discharge, and the set times t1 to t3 are appropriately registered in advance. . Further, the pulse widths T1 and T2 of the waveform control circuit 47, which are the set values of the drive signal S3, and the voltage V of the variable DC power supply 46 are appropriately adjusted. Then, the sensitivity and the mounting position of the ejection sensor 34 are properly adjusted.

To create such an initial state, the initialization work is performed prior to the start of the refueling work. The initial oil supply operation will be described with reference to FIGS. 9 and 10. First, when a work start button (not shown) of the refueling operation panel 42 is turned on (step n31), the solenoid valves 1 and 31 on the side of the supply tank 16 are connected to the compressor, and the solenoid valves 2 and 3 are connected.
2 is not connected (step n32), then the solenoid valves 3 and 33 on the side of the recovery tank 22 are connected to the vacuum pump (step n33), and the oil supply device 10 is No. 1 in FIG. In this state, the oil 17 is sent from the supply tank 16 to the liquid chamber 11a through the supply tube 18. This state continues for a predetermined set time t1 (step n34). During this time, the liquid chamber 11a is sufficiently filled with the oil 17 and overflows from the discharge port 15b, and the overflowed oil 17 is returned from the recovery cap 21 to the recovery tank 22 through the recovery tube 23. When the elapsed time t exceeds the set time t1, the solenoid valves 1, 3
1 is connected to the atmospheric pressure, the solenoid valves 2 and 32 are not connected (step n35, No. 4 in FIG. 10), the excess oil 17 on the discharge port 15b surface is removed, and the oil surface is stabilized and initialization is performed. Be done. In this state, a predetermined set time t2 has elapsed (step n
36), the solenoid valves 3 and 33 are not connected (step n3
7) and the discharge ready state (No. 1 in FIG. 10) is reached, and the initialization work is completed.

When the automatic initialization work is completed as described above, the refueling work state is entered. The discharge operation at this stage is shown in FIG.
It will be explained by. The initialization work for confirming the above-mentioned initialization state is step n41. The oil supply device 10 waits for the carrier positioning completion signal S1 from the leg controller 2 in this initial state (step n42). When the signal S1 is received, the presence or absence of the detection signal S4 of the ejection sensor 34 is checked (step n43), and at this point the ejection sensor 34 is detected.
Has already output the detection signal because the discharge sensor 34
Therefore, the sensor adjustment, that is, the program is interrupted, the discharge sensor 34 is inspected and adjusted (step n44), and the program is restarted.

If there is no abnormality in the discharge sensor 34, the control circuit 41 outputs the refueling signal S2, and the drive signal S3 is output from the waveform generating circuit 44 to which the refueling signal S2 is input (step n45). The piezoelectric element 14 is driven by the shaped drive signal S3, and the liquid chamber 11 described above is driven.
By the operation of a, the droplet 2 is discharged from the ejection port 15b of the nozzle 15.
5 is discharged. The ejection sensor 34 detects the tip of the nozzle 15 (step n47) until the elapsed time t after the drive signal S3 is issued reaches the set time t3 (step n47).
46), and if the droplet 25 is not detected during that time, it is determined that the ejection error has occurred, the number of detection errors is counted, the process returns to step n43, and the drive signal S3 is output again. When the ejection failure is detected continuously for a predetermined number of times n1 (for example, three times) (step n48), the number of detections is reset, an error signal S6 is issued to the leg controller 2 (step n51), and an error process (step n52) is performed. ).

When the discharge sensor 34 detects the discharge, it is determined that the discharge has been normally performed, the number of discharges is counted, and a predetermined number of discharges n2 (for example, two) of discharge operations performed by one refueling (step n43). ~ N49), the number of discharges is reset and one refueling operation is completed, and the refueling completion signal S5 is output to the leg controller 2 (step n50) to return to the initial state (step n42). Note that during one refueling operation, the drive signal S3 is issued a required number of times in accordance with the set ejection number n2 (for example, twice) in step n45, and therefore, the presence or absence of ejection is checked in step n46 each time. Therefore, when the number of discharges is insufficient, additional discharge is performed, so that the amount of oil supply per oil supply can be stabilized.

The contents of the error processing in step n52 will be described. Through hole 1 of nozzle 15 for some reason
When bubbles are generated in 5a, the droplet 25 is not ejected although the drive signal S3 is emitted, and therefore the ejection sensor 34 may not detect the droplet 25. In such a case, it is necessary to eliminate bubbles. This bubble elimination operation will be described with reference to FIG. Even if the ejection operation is repeated, if there is no ejection for a predetermined number of times n1 (for example, 3 times), it is determined that bubbles have occurred, and the ejection operation is interrupted (step n61).
Then, the solenoid valves 1 and 31 of the supply tank 16 are not connected, and the solenoid valves 2 and 32 are connected to vacuum.
No. 0 The state becomes 2 and the liquid chamber 11 is added to the refueling tank 16.
All the oil 17 on the a side will be sucked back. After the predetermined set time t3 (step n63), steps n64 to n6 which are the same as steps n32 to n37 in the initial refueling mode.
In step 9, the discharge work is restarted (step 70).

Next, the viscosity of the liquid will be considered. Oil 1
The viscosity of 7 generally changes greatly in inverse proportion to room temperature. For example, the viscosity of V-rube, the oil 17 for watches, is 2 at 20 ° C.
What is 40 cp becomes 170 cp at 25 ° C. It is necessary to drive the piezoelectric element 14 with a stronger pulse as the liquid becomes more viscous. Therefore, it is necessary to set the drive voltage V according to the viscosity as described above.

In order to set the drive voltage V according to the viscosity of the liquid, it is possible to incorporate in the controller 40 a temperature compensation circuit for correcting the drive voltage V according to the output of the temperature sensor 36. In order to handle a liquid whose viscosity is not within the above range, it is advisable to control the temperature of the liquid in order to maintain the viscosity within the optimum range. By doing so, it becomes possible to heat the liquid having a relatively high viscosity at room temperature to reduce the viscosity and to stably discharge the liquid. In order to keep the viscosity constant, it is desirable to work in a temperature-controlled room where the temperature is kept constant, but it is more preferable to control the temperature of the liquid by using the temperature controller 30. According to the liquid ejection method of the present invention, approximately 30 to 30
Although it can be applied to a liquid having a viscosity range of 0 cp without any problem, the optimum range is 100 to 150 cp. The frequency in the case of continuous discharge varies depending on the viscosity of the liquid, but can be in the range of approximately 5 to several tens Hz.

In the above-mentioned embodiments, the method of discharging the liquid has been described by taking the oil supply to the timepiece module as an example, but the present invention is not limited to this, and an adhesive,
It goes without saying that it can be widely applied to various liquids such as medicines.

[0042]

According to the present invention, since the liquid is ejected in the form of liquid droplets, the ejection amount becomes stable. Furthermore, it became possible to discharge a very small amount. Since the waveform control circuit of the drive circuit has a time constant so that the trailing edge of the drive waveform is made gentle, stable ejection is possible without producing bubbles in the nozzle. Further, since the liquid level of the supply tank is set lower than the tip of the nozzle, the liquid level at the discharge port is stable. Further, since the ejection amount is controlled by the number of ejections (the number of droplets), the fine adjustment of the ejection amount becomes easy. Further, by adjusting the liquid temperature to control the viscosity, or by adjusting the drive voltage according to the liquid temperature, stable discharge of a liquid having a relatively high viscosity has become possible. Furthermore, by adding the function of detecting whether or not there is a discharge, a discharge error can be compensated at that time, and an inspection in a subsequent process becomes unnecessary. Since it has an automatic initialization function, there is no need for maintenance when creating an initial state or during maintenance. In addition, the refueling device is not in contact with the part to be ejected, it does not damage the part to be ejected and the position of the nozzle in the height direction is easy to set. It can also be ejected to places where it was not possible. As described above, according to the present invention, it is possible to provide a liquid ejecting method and an apparatus therefor which are suitable for ejecting an appropriate amount of a liquid having a relatively high viscosity to a fine portion in a stable manner.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a refueling process of a timepiece assembly line that is an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an overall configuration of the oil supply device of FIG.

FIG. 3 is a cross-sectional view of main parts of the oil supply device of FIG.

FIG. 4 is a block diagram of a drive circuit of the oil supply device of FIG.

5 is a waveform diagram of a drive signal of the oil supply device of FIG.

FIG. 6 is a flowchart of the operation of the liquid chamber.

FIG. 7 is a conceptual diagram of the operation of the liquid chamber.

FIG. 8 is an operation flowchart of a conveyor leg.

FIG. 9 is an operation flowchart of liquid level initialization.

FIG. 10 is a state diagram showing a state of the oil supply device of FIG.

11 is an operation flowchart of the oil supply apparatus of FIG.

FIG. 12 is an operation flowchart of bubble removal.

FIG. 13 is an explanatory view showing a conventional watch refueling method.

[Explanation of symbols]

 11a Liquid chamber 12 Thin plate 14 Piezoelectric element 15 Nozzle 15b Discharge port 16 Supply tank 17 Oil 18 Supply pipe 21 Recovery cap 22 Recovery tank 34 Ejection presence / absence detection sensor 40 Controller 41 Control circuit 44 Waveform generation circuit 47 Waveform control circuit 50 Droplet S3 drive Signal V drive voltage

Claims (9)

[Claims] 1. A supply tank for supplying a liquid, a liquid chamber filled with the liquid, a nozzle for discharging the liquid from the liquid chamber,
An elastic plate forming a part of the liquid chamber, a piezoelectric element arranged so that one end abuts on the elastic plate, and a drive circuit for driving the piezoelectric element, and supplies liquid to the liquid chamber. And a step of discharging the liquid filling the liquid chamber from the tip of the nozzle into droplets by driving the piezoelectric element by a drive signal from the drive circuit. . 2. The drive circuit includes a waveform generation circuit that generates a pulse waveform that is the drive signal, and a waveform control circuit that shapes the pulse waveform, and the pulse is generated according to a time constant of the waveform control circuit. The liquid ejection method according to claim 1, wherein the falling of the waveform is made gentle. 3. The liquid discharge according to claim 1, wherein the supply tank and the liquid chamber are connected by a supply pipe, and the liquid level of the supply tank is arranged to be lower than the tip of the nozzle. Method. 4. The liquid ejecting method according to claim 1, wherein the viscosity of the liquid is controlled by adjusting the temperature of the liquid. 5. A detecting means for detecting the temperature of the liquid,
The liquid ejection method according to claim 2, wherein the drive voltage of the drive signal is adjusted according to the detection result of the detection means. 6. The liquid discharge method according to claim 1, further comprising a discharge presence / absence detection sensor for detecting discharged droplets. 7. A means for recovering the liquid in the liquid chamber, comprising an automatic initialization function for filling the liquid chamber with the liquid and adjusting the liquid surface of the nozzle discharge port. The described liquid ejection method. 8. The liquid discharging method according to claim 1, wherein the liquid is watch oil, and the liquid is applied to a watch assembly. 9. A supply tank for supplying a liquid, a liquid chamber filled with the liquid, a nozzle for discharging the liquid from the liquid chamber,
An elastic plate forming a part of the liquid chamber, a piezoelectric element arranged so that one end abuts on the elastic plate, and a drive circuit for driving the piezoelectric element, and a drive signal from the drive circuit. The liquid ejecting apparatus is characterized in that the liquid filling the liquid chamber is ejected into droplets from the tip of the nozzle by driving the piezoelectric element.