JPS6393373A - Liquid droplet forming apparatus - Google Patents

Abstract

PURPOSE:To enhance the quality of a product by holding the dripping speed at a constant liquid droplet forming position, by detecting a state from the start of the dripping of a solution to the adhesion of said solution to an object in timing made synchronous to a period of vibration and adjusting the pressurizing degree to the dripping solution and vibration amplitude. CONSTITUTION:In a liquid droplet forming apparatus used in an ink jet type printer or a cell sorter, a solution 4 is injected in a nozzle 1 under the pressure preset by a liquid pressurizing part 5 and dripped from the nozzle 1 as a liquid droplet by a vibrator 2 vibrated at the cycle of the clock signal CLK from an exciting part 7. The interval of the liquid droplet is synchronous to a period of vibration and the image of the solution dripped is picked up in a stationary state in synchronous relation to the on-and-off of an LED array 9 and guided to a detector 11 by a light receiving part optical system 10 and the dripping time of the liquid droplet is calculated by data processing. When this dripping state varies, a control judge part 12 controls the exciting part and a pressure control part 6 corresponding to a variation value.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is used in a droplet forming device that ejects ink used in an inkjet printer, and a cell sorter that is a type of microparticle analysis device. The present invention relates to a droplet forming device that ejects a sample solution, and particularly relates to a droplet forming device that stably ejects ink or sample solution.

[Prior Art 1] A droplet forming device used in an inkjet printer, a cell sorter, etc. forms droplets in a constant state by applying vibration to the nozzle using an excitation means to cause ink or sample solution ejected from a nozzle to vibrate.

In this case, to prevent droplet fluctuations due to vibration changes,
Until now, the following efforts have been made.

(1) Using an optical means such as a laser, the distance between droplets dropped from a nozzle is measured in a non-contact manner, and a deviation in the distance is detected from the results. Based on this detection result, the excitation means is controlled to correct the droplet spacing to be constant.

(2) In a droplet formation device mainly used in inkjet printers, a charge is applied to droplets ejected from a nozzle in synchronization with an excitation cycle, and the amount of charge on the droplets is measured.

Then, a deviation in the interval between the droplets is detected from the variation in the measured amount of charge, and based on this result, the excitation means is controlled to correct the interval between the droplets to be constant. In the manner described above, a stable droplet state was formed. A stable droplet is
This is important for improving print quality and analysis accuracy.

[Problems to be Solved by the Invention] By the way, in the conventional droplet forming device, in order to keep the droplet interval of the droplets dripping from the nozzle constant, the above-mentioned (1)
) and (2), but these measures the state of the droplet only at the point where the solution ejected from the nozzle forms a droplet, so the state after the droplet is measured. I couldn't figure it out. Therefore, it was not possible to improve printing quality or analysis accuracy due to fluctuations after the droplet.

This invention was made against this background, and its purpose is to provide a dropletization device that can detect the state of a solution from the start of dropping until it is attached to an object or collected. It is in.

[Means for Solving the Problems] The present invention provides a nozzle for spouting a solution, a pressurizing means for sending a pressurized solution to the nozzle, an excitation means for applying vibration to the nozzle, and an excitation means for applying vibration to the excitation means. and an oscillating means for supplying a signal, the detection region is defined as the period from the start of forming a drop of the solution ejected from the nozzle until the droplet reaches a steady state of deafness, and the oscillation period of the oscillating means a detection means for detecting a solution image in synchronization with the detection means; and a detection means for analyzing the dripping state of the solution from the detection result of the detection means, and controlling the excitation so that the analyzed dripping state matches a predetermined dropping state. It is characterized by comprising a control means for controlling the excitation waveform of the means and the pressing force of the front five pressurizing means.

[Operation] According to the above configuration, the solution drips from the nozzle to form droplets in synchronization with the cycle of vibration applied to the nozzle, and the state in which the droplets are dropped is further synchronized with the vibration cycle. Since the droplet formation position and the droplet spacing can be detected, the results can be used to adjust the degree of pressure applied to the solution supplied to the nozzle and the amplitude of the vibration applied to the nozzle. A constant droplet formation position and dropping speed are maintained.

[Example code] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention. In the figure, l is the jet stream nozzle (
(hereinafter simply referred to as a nozzle), it has a tapered opening at the lower end, and a cylindrical upper part.
A disc-shaped vibrator 2 is attached to this upper end. A through hole is formed in the vibrator 2 along the central axis, and an injection tube 3 is passed through the through hole.

A solution 4 is introduced into the injection tube 3 via a liquid pressurizing section 5 . The liquid pressurizing section 5 pressurizes the solution 4 and causes it to flow into the injection tube 3. The pressurizing force is controlled by the pressurizing control section 6.

The pressurization control section 6 performs pressurization control based on the pressurization control data DP supplied from the control determination section 12. In this case, if the pressurization control data DP includes information for increasing the degree of pressurization of the liquid pressurizing section 5, the liquid pressurizing section 5 increases the pressure of the solution 4 supplied to the injection tube 3. As a result, nozzle l
The dropping speed of the solution 4 that is dropped from the droplet increases. Conversely, if the pressurization control data DP includes information for reducing the degree of pressurization, the pressure of the solution 4 supplied to the injection tube 3 will be reduced, and therefore the dropping speed of the solution 4 will be reduced. Reference numeral 7 denotes an excitation unit that supplies excitation power to the vibrator 2, and the vibration period and phase are determined by the clock signal CLK from the oscillator 8. The excitation unit 7 also receives excitation control data D supplied from the control determination unit 12 .

The amplitude of vibration is controlled by In this case, if the excitation control data DO includes information that increases the amplitude of the vibration of the excitation section 7, the excitation section 7 increases the excitation power supplied to the vibrator 2. As a result, the position where the solution 4 drops from the nozzle 1 becomes a droplet approaches the nozzle l. Conversely, if the excitation unit data DO has information that reduces the amplitude of vibration, the excitation power supplied to the vibrator 2 will become smaller, so the solution 4
The droplet formation position moves away from the nozzle. Next, 9 is an LED array, in which light emitting diodes are arranged at equal intervals. Further, this LED array 9 blinks in response to the drive pulse LP supplied from the control determination section 12. The period of this drive pulse LP is synchronized with the clock signals CI and K from the oscillator 8. For this reason, LED
By blinking the array 9, droplets falling from the nozzle 1 can be captured stationary based on the principle of strobe irradiation. IO is a light receiving optical system, which guides a static image of a droplet captured by blinking of the LED array 9 to a detector 11 using a fiber and a lens. The detector 11 detects the droplet image from the light-receiving optical system 10, and is composed of a large number of light-receiving elements (for example, photodiode array, COD, etc.) with sufficient resolution to analyze the droplet image. . A signal D A representing the liquid m image received by the light receiving element of this detector 11
+ to DAn are supplied to the control determination section 12. In this case, the data DA l of the light receiving element
-D An is read out in order from the first element using the read clock RP supplied from the control determination section 12. The control determination unit 12 analyzes the detection data D A + to DAn from the detector 11 and determines whether the nozzle!
The change in the droplet formation position of the solution 4 dropped from the droplet and the variation in the dropping speed (flow rate) of the droplet are calculated and the results are determined. As a result of the determination, if the droplet formation position has changed, the control determination unit 12 controls the excitation unit 7 to control the amplitude of the vibrator to return the droplet formation position to the target value, and if the droplet formation position has changed. In this case, the pressurization control section 6 is controlled to change the pressurization of the solution 4 by the liquid pressurization section 5 to match the target speed.

The method by which the control determination unit 12 analyzes the stratification position and dropping speed of the solution based on the detection data DA and -DAn will be described later.

Next, the operation of this embodiment will be explained with reference to FIG. Clock signal CLK from the oscillator 8 (Fig. 2 (a)
) is supplied to the excitation unit 7 and the control determination unit 12, and the control determination unit 12 supplies the drive signal LP (see FIG. 2(b)) to the LED array 9, causing it to blink. At the same time, the excitation section 7 causes the vibrator 2 to vibrate at the period of the clock signal CLK. At this time, the solution 4 is
is pressurized at a preset pressure and injected into the nozzle L, and the vibration of the vibrator 2 causes the nozzle 1 to
After forming a liquid column from the bottom end of the liquid, it becomes a droplet and drips down.

This dropping interval is synchronized with the vibration period. When the solution 4 dropped as droplets from the nozzle 1 passes between the LED array 9 and the light receiving optical system IO, it is projected in a stationary state in synchronization with the blinking of the LED array 9. The image of the droplet is then guided to a detector 11 by an optical system 10. in this case,
The relationship between the liquid dropped from the nozzle l and the detection data D A I - D A n output from the detection ill is shown in the third table.
As shown in the figure. FIG. 3(a) shows the waveform of the detection data D A l-D An output from the detector 11, and
b) is the waveform shaped data of the detection data DA,=DAn by the control determination section 12.

The image guided to the detection 511 is the detection data D A + ~ D
The signal is converted into An and supplied to the control determination section 12. The control determination section 12 detects the detected data DA, =DA
Data PDA after waveform shaping of n.

~Convert to PDAn. In addition, in FIG. 2(c), the signs of the data PDA+ to PDAn are reversed, and the data PDA1 to PDAn are inverted from the blinking of the LED array 9.
This is to make it easier to understand how n is output. FIG. 2(d) shows data PDA1 to PDAn subjected to peak hold processing. This is because the detection data DA1 to DAn from the detector 11 are discrete data, so if peak hold processing is performed, processing becomes easier at the data processing stage. Next, the control determination unit 12 calculates the droplet dropping time from the data PDA to PDAn.

For example, in FIG. 2(c), the time (t, -1+) from data PDA to data PDA corresponds to the time interval between droplets. The control determination unit 12 monitors the state of the droplet based on the waveform from the detector 11 described above.

Now, suppose that there is a fluctuation in the droplet dropping state and the synchronization is lost, the control determination unit 12 calculates the fluctuation value from the detection data D A I-D A n supplied from the detector 11 and calculates the result. , controls the excitation section 7 and the pressurization control section 6. For example, in FIG. 4, (A) is the detector 11.
This is the standard output waveform, and FIG. This is because the time until the droplet is formed is longer than the reference time, and in order to compensate for this, the control determination section I2
A data signal Do whose amplitude is increased is output to.

In addition, the same figure (c) shows the time T1 required for one cycle of the reference waveform.
This shows the case where it is longer. This is because the dropping speed of the droplets has become slow, and in order to compensate for this, the control determination section 12 outputs a data signal DP to the pressurization control section 6 to increase the pressure. Furthermore, even in the opposite case to the above, the control determination section I2 controls the excitation section 7 and the pressurization control section 6.
control each.

As a result of the above, the droplets dropping from the nozzle 1 can be kept constant.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, a droplet forming device is applied to a cell sorter.

A cell sorter is a device that separates particles (eg, cells, etc.) contained in a sample solution. This cell sorter includes a droplet forming device according to the first embodiment, a charging means for charging the sample solution 19, a deflection means for deflecting the droplets by applying an electric field to the solution dropped as droplets, and a droplet-forming device. This can be realized by adding an optical detection means for optically detecting particles contained in the sample solution 19 dropped as a sample solution. The important function of the cell sorter is to detect particles in the sample solution 19 using optical means immediately after the sample solution 19 is dropped from the nozzle 1 in the form of a liquid column, and the sample solution 19 becomes droplets containing particles. The reason is that it is charged at certain positions.

That is, it is necessary to avoid charging each particle contained in the sample solution 19 within the nozzle.

If the charging timing of the solution containing particles is shifted due to some influence, the solution will not be charged at the droplet formation position.

For this reason, the particles are not collected by the deflecting means, and the detection accuracy is reduced.

By the way, the time required for the sample solution 19 to flow down from the particle detection position (point A) to the droplet formation position (point B) is
9 and the distance from the detection position (point A) to the droplet formation position (point B). For this reason,
By controlling the flow rate of the sample solution 19 and the droplet formation position, the droplet formation position can always be kept constant. First, by detecting the droplet formation position at a position where the droplet leaves the liquid column and then detecting and controlling the fluctuation of the droplet from this position, the droplet formation position can be reliably set at a constant position. . In order to determine the position of this droplet formation, the detection data value at the instant when the droplet is formed is determined from among the detection data DA, ~DAn from the detector 11, and the fluctuation value is determined based on this value. It is sufficient to calculate the fluctuation value and compensate for the fluctuation value. For this purpose,
By changing the amplitude of the vibration of the excitation unit 7, the fluctuation value can be compensated for. FIG. 6 shows how droplets are formed and how their data PDA changes. In the figure, data P D A r at the position shown in (c) in the figure is the value at the droplet formation position from the state of droplet formation in one period of the vibrator 2. This value may be stored in the control determination section 12 in advance. Here, point B shown in FIG. 7(A) is the droplet formation position, and the detection data DA shown in FIG. 7(B),
is the data value at that position. Next, after the droplet formation position is determined, in order to keep the dropping speed (flow rate) of the sample solution 19 constant, the time Tv between droplets (see Figure 7 (b)) is adjusted to be constant. The pressurization control section 6 is controlled.

In this case, compensation for variations in the time Tv between droplets is performed as follows. A reference output waveform of the detector 11 is stored in advance in the control determination section 12, and the control determination section 12 controls the pressurization control section 6 based on this reference output waveform. The above operations are performed based on the work program written in the memory within the control determination section 12.

Next, the above-mentioned droplet formation position (point B) and the particle detector 14
The timing time Td for charging the droplet can be determined from the particle detection position (point A) and the dropping speed (flow speed) (2) using the following equation.

Td=lA-Bl/V Since the value of Td is determined by the droplet formation position (point B) and the dropping speed V, when these change, the charging timing becomes the droplet formation position. As described above, since the droplets are reliably charged, the accuracy of particle aggregation is significantly improved.

Here, to explain in detail the operation of charging a droplet, the fifth
In the figure, a sample solution 1 pressurized by a liquid pressurizing section 5
9 and the sheath liquid 20 are injected into the nozzle l, and the sample solution 19
When sample solution 19 is surrounded by sheath liquid 20 and drops from nozzle l and passes through the optical path of light source 13, if particles are present in sample solution 19, scattered light and fluorescence are generated. This scattered light and fluorescence are detected by a particle detector 14, and particle detection data is supplied to a data analysis particle determination section 15.

The data analysis particle determination unit 15 determines the type of particle from the particle detection data, and determines the output voltage of the charging circuit 16 and its polarity according to the type. The charging circuit 16 applies voltage to the electrode 18a attached to the tip of the injection tube 3. In this case, the charging circuit 16 is controlled by the control determination unit 12 for a period of time until the voltage is applied to the electrode 18a. When the solution containing charged particles passes between the deflection plates 17a and 17b charged by the high-pressure section 21, the solution is deflected or goes straight due to the electric field formed by the deflection plates, and flows straight into the container 2.
Enter either 0a, 20b, or 20c.

Note that the output control of the vibration applied to the nozzle includes amplitude, frequency, and phase, and in the embodiment of the present invention, the amplitude is controlled.

[Effects of the Invention] As explained above, according to the present invention, a nozzle for spouting a solution, a pressurizing means for sending a pressurized solution to the nozzle, an excitation means for applying vibration to the nozzle, and an excitation means for applying vibration to the nozzle. and an oscillating means for supplying a vibration signal to the oscillator, the detection region is defined as the period from the start of droplet formation of the solution ejected from the nozzle until the droplet reaches a steady state; a detection means for detecting a solution image in synchronization with the oscillation cycle, and analyzing the dripping state of the solution from the detection result of the detection means, so that the analyzed dripping state matches a predetermined dropping state, Since it is equipped with a control means for controlling the excitation waveform of the surface excitation vibration means and the pressurizing force of the pressurizing means, it is possible to always keep stable the droplet formation position and dropping speed of the solution ejected from the nozzle. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
2, 3, and 4 are waveform diagrams for explaining the operation of the same embodiment, FIG. 5 is a block diagram showing the configuration of a cell sorter that is a second embodiment of the present invention, and FIG. 6 , FIG. 7 is a waveform diagram for explaining the operation of the same embodiment. l... Nozzle, 5... Liquid pressurizing section, 6... Pressurizing control section (liquid pressurizing section 5 and pressurizing control section 6 constitute a pressurizing means), 7... Excitation section (The excitation unit 7 constitutes an excitation means), 8... Oscillator (The oscillator 8 constitutes an oscillation means)
, 9... LED array, 10... Light receiving unit optical system, 1
1... Detector (the LED array 9, the light receiving unit optical system 1O, and the detector 11 constitute the detection means), 12... the control determination section (the control determination section 12 constitutes the control means), 16. . . . Charging circuit, 18 . . . Charging unit (The charging circuit 16 and the charge unit 18 constitute charging means). Patent applicant Showa Denko Co., Ltd. Figure 1 Figure 2 - A') C:l-

Claims (6)

[Claims] (1) A droplet consisting of a nozzle for spouting a solution, a pressurizing means for sending a pressurized solution to the nozzle, an excitation means for applying vibration to the nozzle, and an oscillation means for supplying a vibration signal to the excitation means. in the oscillating device, the detection region is a period from the start of formation of droplets of the solution ejected from the nozzle until the droplets reach a steady state, and a detection means detects a solution image in synchronization with an oscillation cycle of the oscillation means. Then, the dripping state of the solution is analyzed from the detection result of the detection means, and the excitation waveform of the excitation means and the application of the pressure means are adjusted so that the analyzed dripping state matches a predetermined dropping state. 1. A droplet forming device comprising: a control means for controlling a pressure; and a control means for controlling the pressure. (2) The detection means irradiates the solution that has been dropped from the nozzle and turned into droplets with a light source that blinks in synchronization with the oscillation cycle from the oscillation means, and detects an image of the shadow of the droplet using light. Claim 1, characterized in that the detection is performed by a detection element.
Dropletization device as described in . (3) The control means, based on the detection result of the detection means,
Claim 1 or 2, characterized in that the method has a function of analyzing the time when the solution first becomes a droplet and the dropping speed of the solution as parameters indicating the dropping state. dropletization device. (4) The droplet forming apparatus according to claim 3, wherein the control means controls the excitation means based on a time when the solution first becomes a droplet. (5) The droplet forming apparatus according to claim 3, wherein the control means controls the pressurizing force of the pressurizing means based on an analysis result of the dropping rate of the solution. (6) The droplet forming device includes charging means for charging the solution dripping from the nozzle in the form of droplets at a timing synchronized with the oscillation cycle from the oscillation means. The droplet forming device according to any one of the ranges 1, 2, 3, 4, or 5.