JP2003149020A - Minute flow rate-measuring apparatus and method, computer program, and record medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for accurately measuring a minute flow rate, especially the flow velocity, namely the flow rate of droplets in real time. SOLUTION: The minute flow rate-measuring apparatus comprises a nozzle apparatus that is a nozzle apparatus (1) having a fixed aperture and ejects a fixed number of droplets per unit time, pieces of supply apparatus (2, 3) for supplying liquid to the nozzle apparatus (1), and pieces of detection apparatus (6, 7, and 8) for detecting the interval among a plurality of droplets (111) that are ejected from the nozzle apparatus (1). The detection apparatus advantageously has a mechanism (6) for giving strobe lighting in synchronization with the ejection of droplets, a camera (7) for imaging the images of a plurality of droplets that are synchronized and stopped by strobe lighting, and a processor (8) for measuring the interval among droplets by extracting the amount of feature from droplet images.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for identifying a property of a droplet, and more particularly to a device for identifying a property of a droplet forming a minute flow rate, and an apparatus for measuring and controlling a related minute flow rate. is there. The present invention also relates to this method, a computer program, and a storage medium storing the same.

[0002]

2. Description of the Related Art In the process of research, development and manufacturing of chemicals, it has been practiced to print and add a reagent solution to strips such as nitrocellulose membrane in a reproducible manner. Examples of this include publicly known documents such as Japanese Patent Publication No. 7-6.
975, "Apparatus and Method for Reagent Solution Preparation and Printing".

For printing and adding, conventionally, a means has been used in which a droplet of a reagent is ejected toward a nitrocellulose membrane by a nozzle device which transforms a liquid supplied under pressure into droplets. However, since the liquid volume and other properties of this reagent may change due to concentration, etc., and the flow rate may change due to the accumulation of solidified substances in the nozzle and other paths, the flow rate of the reagent may change. It was necessary to identify and even adjust the flow rate.

The same phenomenon occurs in the ink supply mechanism of the ink jet printer, and it is necessary to adjust the minute flow rate in the liquid flow path.

Conventionally, the detection of the current flow rate for making these adjustments has been performed by visually observing the ejection amount from the nozzle, detecting the weight of a certain number of ejected droplets, and the like.

However, when adding reagents or using ink for ink jet printers, it is necessary to adjust the flow rate with high precision in the first place, and concentration or deposition on nozzles or other channels frequently or randomly occurs due to the liquid. For this reason, it is necessary to adjust the minute flow rate in real time, and there is a drawback in that the desired effect cannot be sufficiently achieved by the conventional visual recognition and accumulation speed detection.

[0007]

SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide a device for measuring and controlling the flow rate of a liquid having a minute flow rate with high accuracy and in real time.

Another object of the present invention is to provide a device for simultaneously measuring and identifying the volume, viscosity, specific gravity, surface tension, etc. of the ejected droplet, and controlling the flow rate and properties.

[0009]

SUMMARY OF THE INVENTION The present invention is a minute flow rate measuring device made in view of the above object, which is a nozzle device having a constant diameter and ejecting a constant number of droplets per unit time. The most main feature is that the apparatus includes a device, a supply device that supplies liquid to a nozzle device, and a detection device that detects a gap between a plurality of droplets ejected by the nozzle device.

A nozzle device having a constant diameter is capable of ejecting droplets at a velocity that correlates with the flow rate, and on the premise that a constant number of droplets are ejected per unit time.
The droplet spacing is directly related to the flow rate.

In addition, the droplet interval reflects the flow rate at that point in real time, and by detecting the interval, which is a physical quantity that can be detected with higher accuracy, the first object of the present invention can be achieved. It is possible.

The present invention also provides a liquid property measuring device, which is a nozzle device having a constant diameter and ejecting a fixed number of liquid droplets per unit time, and a liquid for the nozzle device. A supply device for supplying and a detection device for detecting an interval between the plurality of droplets ejected by the nozzle device are provided.

The liquid property to be measured can be any one of the volume, viscosity, specific gravity and surface tension of the ejected droplet.

The basic principle is the same as that of the above flow rate measuring device. The volume of the ejected droplet reflects the flow rate as it is. Further, the viscosity, specific gravity, surface tension, etc. of the liquid itself correlate with the flow rate and hence the injection speed, and can be detected by the same method as the flow rate.

The detection device is preferably a mechanism for providing stroboscopic illumination synchronized with the droplet ejection, a camera for capturing images of a plurality of droplets which are synchronized and stationary by the stroboscopic illumination, and a feature amount from the droplet image. A processor for extracting and measuring the droplet spacing.

Strobe illumination synchronized with droplet ejection allows a series of droplets that are ejected and moved at a high frequency, that is, at a high frequency, to be viewed as a plurality of still stationary droplets on a video image. This facilitates the detection of drop spacing with a conventional video camera, such as an industrial or inspection video camera.

The feature amount is preferably obtained by extracting the centroid of the droplet from the droplet image by image processing, measuring the distances between the centroids at several points, and averaging the distances.

As a result, it becomes possible to detect the liquid droplet interval more robustly against disturbances and minute fluctuations.

The nozzle device can include a strained element.

The nozzle using the strained element has a constant bore diameter, the flow rate and the ejection speed are correlated with each other, and the function of producing a fixed number of droplets per unit time can be easily realized.

According to the present invention, the supply of the liquid forming the droplets to the nozzle device is feedback-controlled so that the droplet intervals are constant, based on the measured values of the droplet intervals obtained from these devices. You can

This control can be performed by increasing / decreasing the pressure of the liquid forming the droplets on the nozzle device. This is controlled so that, for example, the pressure is weakened when the droplet spacing is larger than the reference value, and the pressure is strengthened when the droplet spacing is smaller than the reference value. When the allowable range of the reference value is wide, this control may be provided with a certain hysteresis.

Further, it can be carried out by changing the composition of two or more kinds of liquids forming droplets in the nozzle device. When a certain current drop interval is obtained, data such as the change in the composition, for example, the extrusion pressure of each liquid type, that returns the drop interval to the initial value is statistically obtained in advance and stored in a computer memory. Accumulate,
Such a mechanism can be realized by controlling each extrusion pressure while referring to this memory.

These control the flow rate of the liquid supplied in various ways, and thus the volume of the ejected droplet,
It is possible to control the speed.

The present invention also provides a liquid property identification device which outputs a property value by applying a correspondence between a predefined liquid drop interval and a property value to a liquid drop measurement value from the liquid property measuring device.

This makes it possible to display in real time and with high accuracy a property corresponding to the droplet interval, for example, a specific value of the volume of the droplet in a unit that can be immediately grasped by a person.

Such correspondence may be realized as a function by a computer program, and by storing the correspondence between the droplet interval and the volume obtained in advance in a memory in a look-up table format. , May be realized by picking up and displaying the droplet volume value of the record corresponding to the current droplet interval.

In addition to the volume of the liquid droplet, viscosity, specific gravity, surface tension, etc. are reflected in the liquid droplet interval, and the viscosity of the liquid droplet at a certain time can be changed from the certain interval of the droplet by performing backward programming or corresponding measurement. Can be backcalculated or picked up as well.

The present invention also provides a method for measuring a flow rate, which method comprises ejecting droplets from a nozzle device having a constant diameter and ejecting a constant number of droplets per unit time. And a step of detecting an interval between the plurality of droplets ejected by the nozzle device.

This method also makes it possible to measure the flow rate of the flow path itself with respect to the nozzle. Droplet spacing,
By obtaining a mode suitable for image processing, it is possible to detect the flow rate with high accuracy.

The present invention also provides a method for measuring liquid properties, which method comprises ejecting liquid droplets from a nozzle device having a constant diameter and ejecting a constant number of liquid droplets per unit time. And a step of detecting an interval between the plurality of liquid droplets ejected by the nozzle device.

The liquid properties are the volume, viscosity, and
It may be one of specific gravity and surface tension.

This detection step is preferably a step of providing stroboscopic illumination synchronized with droplet ejection, a step of capturing images of a plurality of droplets which are synchronized and stationary by stroboscopic illumination, and a feature amount from the droplet image. And measuring the droplet spacing.

In these methods, the characteristic amount is advantageously obtained by extracting the centroid of the droplet from the droplet image by image processing, measuring the distances between the centroids at several points, and averaging the distances.

Also in these methods, the nozzle device may include a strained element.

Further, there is provided a method of feedback-controlling the supply of the liquid forming the droplets to the nozzle device based on the droplet intervals obtained by these methods so that the droplet intervals become constant.

This advantageously controls the pressure of the liquid forming the droplets on the nozzle device.

Further, the mixture of two or more kinds of liquids forming droplets to the nozzle device may be feedback-controlled so that the distance between the droplets becomes constant.

The present invention also applies a predefined correspondence between the droplet spacing and the property value to the liquid droplet spacing (measured value) obtained from the liquid property measuring method, and outputs the liquid property identification. Provide a way.

According to the present invention, a computer system having at least a means for detecting a physical quantity and a storage means stores an image containing a plurality of ejected droplets in the storage means, and an image stored in the storage means. A program is provided for executing a step of calculating a droplet interval from the above and a step of outputting a value related to the droplet interval.

The step of calculating the drop spacing can advantageously calculate the drop spacing by extracting a feature from the image captured in the storage means.

This feature amount can be advantageously obtained by extracting the centroid of the droplet from the droplet image by image processing, measuring the distances between the centroids at several points, and averaging them.

Such a program enables the highly accurate detection as described above by digital processing via a computer.

The present invention also provides a computer-readable storage medium storing these programs.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION In the embodiments of the present invention, each component is described in a known document, for example, Japanese Patent Publication No. 7-6975.
"Apparatus and method for preparation and printing of reagent solution",
Japanese Unexamined Patent Publication No. 9-1792 “Inkjet System”, US Pat. No. 4,216,483 “LINEAR ARRAY IN
K JET ASSEMBLY, "U.S. Pat.
64 "DEMAND DROP FORMING DE
VICE WITH INTERACTING TRA
NSDUCER AND ORIFICE COMBI
"NATION", U.S. Pat. No. 4,905,503 "METHO"
D AND DEVICE FOR MEASURING
THE VISCOSITY OF A FLUI
The technical contents of “D” can be referred to or applied, and for details of publicly known constituent elements, refer to these.

FIG. 1 shows the overall structure of an embodiment of the present invention.

Reference numeral 1 is a nozzle device for ejecting the microdroplets 111. In particular, it is configured using a strained element,
Droplets can be ejected at an initial velocity proportional to the ejection flow rate. Reference numeral 2 is a flow path for conveying a liquid to the nozzle device, and a liquid reservoir tank (solution container) 21 forms a main part of the flow path. The flow rate can be regarded as the amount of liquid ejected from this reservoir tank through the nozzle device per unit time. Reference numeral 3 is a pressurizing device for generating this flow rate. Reference numeral 4 denotes a pressurizing device controller for controlling the pressurizing device, which has a function of measuring the current pressure of the pressurizing target and a function of controlling the pressurizing amount. Reference numeral 5 designates the ejection frequency of the liquid droplet, and is in synchronization with the imaging system, particularly a strobe 6 described later, and is a physical condition for further ejecting the liquid droplet, here, the ejection timing, the amount of charge applied to the liquid droplet, and after ejection. Is a controller unit that generates each control synchronization signal for dynamically adjusting the influence of the electric field that the liquid droplets of. As a droplet interval detection device, a high-frequency strobe 6 and a drop monitor camera 7 capable of imaging the intervals of a plurality of droplets and outputting as a digital still image.
Then, the video signal from the camera connected to this camera is sequentially taken in as a time series of a digital still image (for example, a non-compressed BMP format or a reversible / irreversible compression format such as PNG), and an average droplet interval is calculated for each still image. And a processor 8 that operates. In another embodiment, the signal line not shown is from the controller unit 5 to the camera 7
The shutter of the camera can be synchronously controlled. The processor 8 calculates the flow rate from the average droplet interval and controls the value.
Analog RGB connected to computer (PC) 10
It is displayed on the display device 9 which is a monitor.

As an example of these operation cycles, it is possible to synchronize the emission and strobe light at 47,000 Hz and the image pickup by the camera at about 60 Hz.

Pressurizing device The controller 4, the controller unit 5, and the processor 8 are housed in a single PC 10, and each of them is connected to an external device or a pressurizing device through a GP-IB interface, or an interface such as RS-232C in another form. In addition to exchanging signals with the device 3, the strobe 6, the camera 7, and the display device 9, it is possible to exchange device-specific data and control signals through an internal bus in the PC 10. With a program stored in advance in a memory (not shown) in the PC 10 and predefined statistical data, not only the flow rate is measured but also the flow rate is controlled to be constant, and information on a droplet interval at a certain time is displayed. It is also possible to identify properties such as viscosity, specific gravity, and surface tension of the liquid droplet at that time, that is, liquid. The PC 10 includes a communication interface for the Internet and a reading device for a portable medium, and the computer program and the statistical data described above can be installed from various external mediums.

Each aspect of this embodiment will be described below with reference to the accompanying drawings. It should be noted that the above and below embodiments and implementations are merely examples, and the scope of the present invention is limited only by the appended claims, and those skilled in the art can implement various modifications within the scope. It is possible.

FIG. 2 is a schematic view showing a mode of ejecting minute droplets from a liquid.

The pressurizing device 3 supplies pressurized air 31 from an air supply device (not shown) to the reservoir tank 2 as the flow path 2.
I am sending it to 1. The amount of air sent in is regulated by the regulator 32 in the pressurizing device 3 based on a signal from the pressure sensor in the pressurizing device 3 or by manual adjustment without using the signal in another embodiment. It

The signal is sent to the pressure measuring unit of the external pressurizing device controller 4 once, and the PC1 for making a judgment by the pressurizing device controller 4 or for further controlling it.
The program, data in 0, and / or the judgment by the relevant devices 5, 8 are sent as signals to the regulator in the pressurizing device. In another embodiment, the signal from the sensor can be sent to the regulator (not shown) only via the control circuit in the pressurizer.

A pressure is applied by the pressurization device 3 to the reservoir tank 21 of the flow path 2, and the liquid in the flow path is pushed out to the nozzle device 1.

The nozzle device 1 is composed of an element that uses a distorted electric element to generate a displacement with respect to an electric signal. The nozzle apparatus 1 vibrates at a constant cycle by a control signal from a controller unit, which will be described later, so that a unit time is constantly maintained. A fixed number of droplets are ejected per unit. When the flow rate is large, the weight per droplet becomes large, but the initial speed of the ejected droplet becomes faster because the size of the nozzle outlet does not change. On the contrary, when the flow rate is small, the initial velocity of the droplet becomes slow. The droplets after ejection have a stable velocity and fly at a constant interval where they balance air resistance, but since the interval is proportional to the initial velocity, a wide droplet interval is used when the flow rate is high, and a narrow droplet interval is used when the flow rate is low. To form.

The recovery container 22 collects the flying droplets,
The recovery pump 23 checks the liquid in the recovery container with the check valve 2
It will be returned to the reservoir tank 2 via 4.

The check valve 24 prevents backflow and enables accurate flow rate measurement.

FIG. 3 is a block diagram showing the configuration of the controller unit 5 for synchronizing the ejection of the droplet and the imaging and adjusting the physical condition regarding the ejected droplet.

The input signal I / F 501 is for performing synchronous control for each circuit in the drawing which generates each control signal for the illumination (strobe) 6, the nozzle 1, and the droplet deflecting device 101. It forms the interface for internal signals, especially from the distributor.

The distributor 11 may be composed of a dedicated branch circuit or a multiplexer circuit, or may be realized via a logical channel using the internal bus of the PC 10.

FIG. 4 is a schematic view showing the correspondence between the elements constituting the droplet interval detecting device according to the present invention and their respective functions. Nozzle control signal for controlling the nozzle device 1 and LED
And a light source control signal for controlling the type strobe lighting 6,
The synchronized control facilitates the generation of a still image of the droplet.

The camera 7 picks up a droplet image of which exposure time is limited with high accuracy by a strobe, and this is taken as, for example, NTS.
It is transmitted to the processor 8 in an analog video format such as C.

In the processor 8, a droplet image moving image in analog video format, but synchronized and appearing to be stationary still, is first replaced by a time series of digital still images by a known method (81), and each After the digital image processing (82) such as feature extraction is performed on the digital still image, the droplet interval is finally measured (83).

The measurement result is controlled so as to be displayed on an appropriate display device 9 such as an RGB monitor, and further, if necessary, transferred as a feedback signal for controlling the pressurizing device or stored in a memory. Or

As the feature extraction of the still image, general methods such as binarization, clustering, and cluster centroid determination can be used.

The droplet interval measurement 83 can be performed by averaging the intervals of a plurality of droplet centroids in the same image, and various other known statistical methods based on the above digitization. Can be used to improve accuracy.

FIG. 5 is a diagram showing the relationship between the nozzle device and its synchronous control mechanism.

Here, in particular, an example in which the user (upper right) manually sets the synchronization condition through the user I / F in order to print the reagent on the nitrocellulose membrane will be described.

The control computer, which receives a command from the input device 12 of the user I / F, sends a control signal to each device, that is, the waveform generator 53, the piezoelectric driver 52, and the high voltage power supply device 54, at an appropriate timing by the internal clock. You can In this example, the piezoelectric driver derives the trigger from an external generator 524, but the trigger could be included in the control signal from the control computer.

The waveform generator 53 generates an output waveform of the charge pin 535 for giving the droplet 111 ejected from the nozzle an appropriate electric charge.

The piezoelectric driver 52 controls the nozzle ejection timing. In the present invention, the injection timing is advantageously controlled to have a constant cycle.

The high-voltage power supply 54 controls the high-voltage plate 536 that forms a high electric field for influencing the traveling direction of the liquid droplets after the nozzle is ejected.

The ejected droplet 111 is the charge pin 5
The degree of deflection is determined by the degree to which the electric charge is received by 35, and for example, it falls to a predetermined position on the nitrocellulose membrane. According to the present invention, for example, the volume of a droplet is defined with high accuracy, and as a result, the degree of deflection can be controlled with high accuracy, and in the end, an appropriate amount can be printed / added to an appropriate position with high accuracy.

FIG. 6 is a diagram showing a correspondence between an image pickup example of droplets ejected from the nozzle by the apparatus of the present invention and a plurality of droplet intervals which is one of the characteristic amounts thereof.

Each ellipse having a polka dot pattern represents each ejected droplet, and the thick frame represents the range of one still image corresponding to one flash of the strobe. The vertical thin line 141 in the thick frame represents the horizontal center of gravity coordinates of the droplet, and the horizontal thin line 142 represents the vertical center of gravity coordinates of the droplet. Each double-headed arrow represents each droplet interval.

In FIG. 6, d1 is the initial drop center of gravity interval, d2 is the next drop center of gravity interval, and dn is the last drop center of gravity interval. Average droplet spacing is d1, d
2 ,. ． ． It is possible to perform the calculation by adding up dn and dividing by n by the processor 8 at high speed and easily.

Such a digital image in which an auxiliary line is added to the image pickup processing result can be digitally displayed on the display device 9 as it is, and it can be displayed together with other information, for example, the calculation result of the average droplet interval. You may At this time, it is possible to display the imaging processing result at each time point in real time.

FIG. 7 is a diagram showing the correlation between the rate of change in the flow rate in each flow path and the rate of change in the droplet spacing of the droplets ejected from the corresponding nozzles in a plurality of independent devices according to the present invention. Is.

Specifically, five flow rate measuring devices (Hea)
(corresponding to d # 1 to Head # 5), the pressure of the pressurizing device was artificially changed to change the flow rate, and the data was compared with the data of the droplet interval measured by this device. In addition, a certain number of droplets were collected under each condition and the weight was measured. As can be seen from FIG. 7, the flow rate change rate and the droplet interval change rate show a good correlation with high accuracy, and the following calculation formula is established. That is, Δf ₀ : initial flow rate (measurement value at a certain reference time point 0 is 100%), Δd ₀ : initial average droplet interval (measurement value at the same reference time point 0), Δf _current : current flow rate (current time point) Estimated flow rate at current x%), Δd
_current : current average droplet interval (current point current)
Flow rate change rate Δf (%) = Δf
_current / Δf ₀ = Δd _current / Δd ₀ , or when the flow rate is to be obtained, the current flow rate Δf _current = Δf ₀ · (Δd
_current / Δd ₀ ).

FIG. 8 shows the image pickup processing, the image processing,
9 is a flow chart showing the operation of a mechanism for controlling the flow rate based on the droplet interval, using the above calculation formula.

First, when the program starts (S15
0), the distance Δd ₀ between the droplets as an initial reference value is measured (S151). This is the current droplet spacing Δd _current at the initial point serving as the reference, and is determined by the droplet spacing measurement (sub) routine (S155) on the left side of the figure, and Δd
_This is achieved by substituting _current for Δd ₀ (S152).

The reference initial point can be considered to be a time point immediately after the state of the system such as the nozzle has been maintained.

Further, the droplet interval measurement (sub) routine (S
Although 152) is shown as a subroutine for convenience, it can be configured to be always executed independently of the flow of the mainstream of the program, that is, the control context, by parallel processing by a multiprocessor, interrupt processing by a single processor, or the like. . In this case,
The program is configured to write the measurement result Δd _{curr ent} at that time in a predetermined position in the memory using a static global variable (S158).

Present Droplet Interval Measurement Routine (S152)
Calculates the _current droplet interval Δd _current as described above, and returns the control to the main flow (when configured as a subroutine) together with this value (S158) (S159).

In the mainstream flow, the obtained Δd _current is substituted for Δd ₀ (S152), and this Δd ₀ is defined as the initial value of the droplet interval, that is, 100%.

When the setting of the initial value is completed in this way, the process then shifts to an infinite loop (repetition) phase (S153, S154) for measuring the change with time of the droplet interval. The infinite loop phase can be interrupted or terminated at an appropriate point by inputting a command from an input device (not shown) of the computer.

In the infinite loop phase, the distance between droplets at that time is measured at regular time intervals (S153, S15).
5 to S159). The measurement is also performed by directly using the inter-droplet distance estimation routine by calling a subroutine or indirectly using a global variable or the like.

The Δd _current thus obtained at that time
And the already obtained Δd ₀ , the calculation formula Δd
The change rate of the droplet interval is obtained from _current / Δd ₀ × 100 (%) (S154), and this is displayed on the display device 9 or the like as the “flow rate” change rate from the initial point.

Such an endless loop may be controlled by the interrupt control as well, or may be controlled by the unconditional branch instruction of the program. In case of interrupt control,
The timer allows the measurement and corresponding display to be repeated automatically at regular intervals.

The combination of Δd _current and Δd ₀ or the ratio of the two can be used as the source of the feedback control signal to the pressurizing device or the like. These digital values are directly or indirectly transmitted to the pressurizing device controller 4 through an internal shared bus or a dedicated channel by the control of the control computer 10 or the like, and the D / A converter of the pressurizing device controller 4 or the like is transmitted. It becomes an analog value via and becomes a control signal to the regulator of the pressurizing device.

Specifically, when the analog value reflecting the droplet interval is larger than a fixed reference value, the regulator controls so as to reduce the pressurizing amount, and when it is smaller, the pressurizing amount is increased. Control to do so. A constant hysteresis is provided for this control. This is preferably provided by a program by the control computer 10. In another embodiment, it is physically provided at the level of the regulator.

The series of mechanisms described above substantially enable the minute flow rate to be detected and controlled accurately and in real time.

[0093]

According to the present invention, it becomes possible to measure the flow rate of a liquid having a very small flow rate, particularly the flow rate of a liquid droplet, with high accuracy and in real time. It is also possible to perform high precision and real-time constant control. In addition, the volume, viscosity, specific gravity of the ejected droplet,
It is also possible to measure and identify the properties of the liquid such as surface tension, and it is also possible to control the minute flow rate based on this measurement.

Further, according to the present invention, regarding flow rate detection,
This makes it possible to detect physical quantities that can be detected with higher precision than intervals.

Further, it is possible to more robustly detect the droplet interval with respect to disturbance and minute fluctuations.

Further, the present invention can easily realize the function of correlating the flow rate with the ejection speed and creating a fixed number of droplets per unit time.

[Brief description of drawings]

FIG. 1 is an overall view showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration for ejecting minute droplets from a liquid.

FIG. 3 is a block diagram showing the configuration of a controller for synchronizing the ejection of a droplet and the imaging and adjusting the physical conditions relating to the droplet.

FIG. 4 is a schematic diagram showing the correspondence between the elements constituting the droplet spacing detection device according to the present invention and their respective functions.

FIG. 5 is a diagram showing a relationship between a nozzle device and its synchronous control mechanism.

FIG. 6 is a diagram showing a correspondence between an image pickup example of a droplet ejected from a nozzle by the apparatus of the present invention and a plurality of droplet intervals which is one of its characteristic amounts.

FIG. 7 is a diagram showing a correlation between a change rate of a flow rate in each flow path and a change rate of a droplet interval of a droplet ejected from each corresponding nozzle in a plurality of independent devices according to the present invention.

FIG. 8 is a flow chart showing an operation of a mechanism for controlling a flow rate based on a droplet interval.

[Explanation of symbols]

1 nozzle 2 channels (most of) 3 Pressurizing device 4 Pressure device controller 5 nozzle-strobe synchronous controller unit 6 Strobe 7 camera 8 Drop Interval Measurement Processor 9 Display device 10 control computer 11 distributor 21 Reagent or ink reservoir tank 22 Collection container 23 Recovery pump 24 check valves 31 Pressurized air 32 regulator 101 Droplet deflecting device 111 droplets

Claims (24)

[Claims] 1. A nozzle device (1) having a constant diameter, which ejects a fixed number of droplets per unit time, a supply device for supplying a liquid to the nozzle device (1), and a nozzle device ( A minute flow rate measuring device, comprising: a detecting device (6, 7, 8) for detecting an interval between a plurality of droplets ejected by 1). 2. A nozzle device (1) having a constant diameter for ejecting a constant number of droplets per unit time, a supply device for supplying a liquid to the nozzle device (1), and a nozzle device ( 1) A liquid property measuring device, comprising: a detection device (6, 7, 8) for detecting a space between a plurality of liquid droplets ejected by 1). 3. The liquid property measuring apparatus according to claim 2, wherein the liquid property is any one of volume, viscosity, specific gravity and surface tension of the ejected droplet. 4. A mechanism (5, 6) in which the detection device (6, 7, 8) provides stroboscopic illumination synchronized with droplet ejection,
It is characterized by comprising a camera (7) for picking up images of a plurality of liquid droplets that are synchronized and stationary by strobe illumination, and a processor (8) for extracting a feature amount from the liquid droplet image and measuring a liquid droplet interval. An apparatus according to any one of claims 1 to 3. 5. The feature quantity is obtained by extracting the center of gravity of the droplet from the droplet image by image processing, measuring the distances between the centers of gravity at several points, and averaging the distances.
The device according to. 6. Device according to claim 1, characterized in that the nozzle device (1) comprises an electrostrictive element. 7. The apparatus according to claim 1, wherein the supply device is feedback-controlled so that the droplet interval becomes constant based on the measured value of the droplet interval. 8. The feed pressure to the nozzle of the supply device is feedback-controlled so that the droplet interval becomes constant based on the measured value of the droplet interval. The described device. 9. Based on the measured value of the liquid droplet spacing, the nozzle device (1) is blended with two or more kinds of liquid forming liquid droplets in the supply device so that the liquid droplet spacing becomes constant. The device according to any one of claims 1 to 6, which is feedback-controlled. 10. The apparatus according to claim 2, wherein a predetermined correspondence between the droplet interval and the property value is applied to the measured value of the droplet interval, and the property value is output. . 11. A method for measuring a flow rate, the method comprising: ejecting liquid droplets from a nozzle device having a constant diameter and ejecting a constant number of liquid droplets per unit time; ), The step of detecting the interval between the plurality of droplets ejected by the above method. 12. A method for measuring a liquid property, the method comprising: ejecting liquid droplets from a nozzle device having a constant diameter and ejecting a constant number of liquid droplets per unit time; 1) The step of detecting the intervals between the plurality of liquid droplets ejected according to 1). 13. The liquid property measuring method according to claim 12, wherein the liquid property is any one of volume, viscosity, specific gravity and surface tension of the ejected droplet. 14. The detecting step includes a step of applying stroboscopic illumination synchronized with droplet ejection, a step of capturing images of a plurality of droplets which are synchronized and stationary by stroboscopic illumination, and a feature amount is extracted from the droplet image. Measuring the drop spacing. 14. A method according to any one of claims 11 to 13, characterized in that the method comprises: 15. The feature quantity is obtained by extracting the center of gravity of a droplet from a droplet image by image processing, measuring the distances between the centers of gravity at several points, and averaging the distances. The method described in. 16. Method according to any one of claims 11 to 15, characterized in that the nozzle device (1) comprises an electrostrictive element. 17. The method according to claim 11, further comprising the step of feedback-controlling the supply of the liquid forming the droplets to the nozzle device (1) based on the obtained droplet spacing so that the droplet spacing becomes constant. 17. The method according to any one of 1 to 16. 18. The method further comprising the step of feedback-controlling the pressure of the liquid forming the droplets to the nozzle device (1) based on the obtained droplet intervals so that the droplet intervals become constant. 17. The method according to any one of 11 to 16. 19. The method further comprising the step of feedback-controlling the composition of two or more kinds of liquids forming a droplet into the nozzle device (1) based on the obtained droplet interval so that the droplet interval becomes constant. 17. A method according to any one of claims 11 to 16 including. 20. The method according to claim 12, further comprising the step of applying a predefined correspondence between the droplet interval and the property value to the obtained droplet interval and outputting the property value. The method described. 21. A computer system (10) having at least a means for detecting a physical quantity and a storage means, a step of loading an image containing a plurality of ejected droplets in the storage means, and an image loaded in the storage means. A program for executing a step of calculating a droplet interval from the output and a step of outputting a value related to the droplet interval. 22. The step of calculating the drop spacing comprises:
22. The program according to claim 21, wherein a feature amount is extracted from the image captured in the storage unit to calculate the droplet interval. 23. The feature amount is obtained by extracting the center of gravity of the droplet from the droplet image by image processing, measuring the distances between the centers of gravity at several points, and averaging the distances.
The program described in. 24. A computer-readable storage medium storing the program according to any one of claims 21 to 23.