JP2001071476A - Apparatus and method for evaluating discharged liquid drop - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for evaluating discharged liquid drops which can more correctly detect a size and a velocity of discharged liquid drops in a simple constitution. SOLUTION: The evaluating apparatus includes an optical sensor 221 with photodetect faces divided in matrix and photoelectric conversion elements set corresponding to the photodetect faces for outputting electric signals corresponding to a quantity of light received, an optical system for guiding light emitted from a light source to each photodetect face of the optical sensor, a signal- processing means 6 for obtaining physical data of liquid drops 11 from a change of output signals of the photoelectric conversion elements when the liquid drops discharged from an ink-jet head block the light guided by the optical system, and a data-processing means for storing and memorizing the physical data obtained by the signal-processing means and converting the data into a state whereby the data can be displayed in a predetermined form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for evaluating a discharged droplet, and more particularly to an apparatus and a method for evaluating the stability and reproducibility of a droplet discharged by an ink jet method. It is.

[0002]

2. Description of the Related Art As an information output device in, for example, a word processor, a personal computer, a facsimile, etc., there is a printer for recording desired information such as characters and images on a sheet-like recording medium such as paper or film.

[0003] Various types of printing methods are known for printers. However, ink-jet printing is possible because non-contact printing is possible on printing media such as paper, colorization is easy, and quietness is high. In recent years, the method has attracted special attention, and its configuration is to mount an inkjet head that ejects ink according to the desired recording information and record while reciprocating scanning in the direction perpendicular to the feed direction of the recording medium such as paper. Are generally widely used because they are inexpensive and easy to miniaturize.

[0004] In order to evaluate an ink jet head used in such an ink jet printer, the discharge stability of liquid droplets discharged from the ink jet head has been evaluated. As specific parameters, parameters such as the volume of a droplet to be ejected, the direction of impact on a recording medium including a main droplet and a satellite droplet, and the ejection speed are measured, and stability and reproducibility are evaluated.

Conventionally, as a device for measuring such a parameter, there is no device devised exclusively, so that a strobe light source such as a xenon tube is conventionally made to emit light at a certain timing, and a discharged droplet image is formed. The above parameters are evaluated based on images taken by a CCD camera or the like.

As a method other than such an image-based method, there is a method which is applied to the measurement of general fine particles in a clean room, an ultrapure water production apparatus, a flow cytometer, or the like. There are known a method of measuring the size of fine particles by measuring the intensity of laser scattered light in a direction, and a method of measuring the velocity by a laser Doppler method.

[0007]

However, the above-described conventional method for evaluating a discharged droplet has the following problems.

A problem with the method using a strobe light source such as a xenon tube is that the light emission cycle and the light emission time cannot be shortened. The ejection cycle of droplets by the inkjet method tends to become shorter and shorter, and the emission cycle of a strobe light source such as a xenon tube cannot be used. Therefore, the strobe light cannot be emitted corresponding to each ejection cycle, and an image can be obtained only intermittently.

Regarding the light emission time, the speed of the droplet discharged by the ink jet method may be about 20 to 30 μm / μsec immediately after being discharged. Tens of nse
Although it is necessary to set it to c, the limit is about 100 nsec for a general strobe light source.

In the method of determining the size of fine particles by measuring the intensity of laser scattered light, it is assumed that the shape of the fine particles is spherical. It is difficult to determine the size correctly.

Further, in the velocity measurement method using the Doppler shift, it is necessary to form an interference fringe of light in a space through which the droplet passes, and in addition, the velocity component is the incident light vector and the vector of the Doppler shifted light. Therefore, it is necessary to perform alignment in the angular direction, and the apparatus becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a discharge droplet evaluation apparatus and discharge apparatus capable of detecting the size and speed of a discharged droplet with a simple configuration. A first object is to provide a droplet evaluation method.

Further, the present invention provides a discharge droplet evaluation apparatus and a discharge droplet evaluation apparatus which can change a light emission cycle and a light emission time in a wide range and can obtain an image of a discharged droplet in various forms. It is a second object to provide a method.

[0014]

The first object of the present invention is to provide an apparatus for evaluating the stability and reproducibility of droplets ejected by an ink-jet method. A head, a light source, an optical sensor having a light receiving surface divided in a matrix and a photoelectric conversion element for outputting an electric signal corresponding to the amount of received light corresponding to each light receiving surface, and light emitted from the light source. An optical system for guiding each light receiving surface of the optical sensor, and when a droplet ejected from the inkjet head blocks light guided by the optical system, a change in an output signal of the photoelectric conversion element causes a physical change of the droplet. Signal processing means for obtaining physical data, and data processing means for accumulating and storing the physical data obtained by the signal processing means and converting the physical data into a form that can be displayed in a predetermined format. Eteiru is accomplished by discharging droplets evaluation apparatus according to the first aspect of the present invention.

A first object of the present invention is a method for evaluating the stability and reproducibility of droplets ejected by an ink-jet method. The method comprises the steps of: A light-guiding step in which an optical system guides each light-receiving surface of an optical sensor having a corresponding light-receiving surface and a photoelectric conversion element that outputs an electric signal corresponding to the amount of received light to each light-receiving surface; When the dropped droplet blocks the light guided by the light guiding step, a signal processing step of obtaining physical data of the droplet from a change in an output signal of the photoelectric conversion element, and the signal processing step is performed in the signal processing step. A data processing step of accumulating and storing the physical data and converting the physical data into a form that can be displayed in a predetermined format. It is.

A second object of the present invention is to provide a droplet evaluation apparatus for evaluating the stability and reproducibility of droplets ejected by an ink jet system, comprising: an ink jet head for ejecting droplets; A light source that emits light, an imaging unit that captures an image of a droplet that is ejected from the inkjet head and is irradiated with the pulsed light, an optical system that guides the pulsed light to the imaging unit, and the pulsed light. Synchronizing means for synchronizing the light irradiation with the driving timing of the ink jet head, and data processing for accumulating and storing an image of the droplet imaged by the imaging means and converting the image into a form which can be displayed in a predetermined format And a discharge droplet evaluation apparatus according to the second aspect of the present invention.

The second object is a droplet evaluation method for evaluating the stability and reproducibility of droplets ejected by an ink jet system, wherein pulsed light is ejected from an ink jet head. A light guiding step of leading to an imaging unit that captures an image of a droplet, a synchronization step of synchronizing the irradiation of the pulsed light with a drive timing of the inkjet head, and an image of the droplet captured by the imaging unit. And a data processing step of accumulating and storing the data and converting the data into a form that can be displayed in a predetermined format.

The first and second objects are a droplet evaluation apparatus for evaluating the stability and reproducibility of droplets ejected by an ink-jet method, comprising: an ink-jet head for ejecting droplets; A first light source for irradiating a first light of one wavelength, a second light source for irradiating a pulsed second light at a second wavelength, and a light source for irradiating the second light with the inkjet head. Synchronizing means for synchronizing with drive timing, first optical means for synthesizing the first and second lights and guiding the light to droplets ejected from the inkjet head,
An optical sensor having a light receiving surface divided in a matrix and a photoelectric conversion element for outputting an electric signal corresponding to the amount of received light corresponding to each light receiving surface, an imaging unit for imaging an image of the droplet, and the droplet Second optical means for separating the light irradiated to the first light and the second light, guiding the first light to the light sensor, and guiding the second light to the imaging means, (2) a signal processing means for obtaining physical data of the droplet from a change in an output signal of the photoelectric conversion element corresponding to the first light guided by the optical means, and the physical data obtained by the signal processing means. Data processing means for accumulating and storing data and an image of the droplet imaged corresponding to the second light guided by the second optical means, and converting the image into a form displayable in a predetermined format; The second aspect of the present invention, It is accomplished by jetting liquid droplets evaluation apparatus according to an aspect of the.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the apparatus for evaluating a discharged droplet according to the present invention will be described below in detail with reference to the drawings.

FIG. 4 is a block diagram showing an overall configuration of an embodiment of a discharged droplet evaluation apparatus according to the present invention. The present embodiment is roughly divided into a part related to droplet discharge, a part that detects and captures a discharged droplet using a sensor and a CCD, and a part that performs overall control.

The portions related to droplet ejection include an inkjet head 10 for ejecting droplets 11 of ink or the like in accordance with an inkjet system, and an inkjet head 1 for ejecting droplets 11 at positions where detection and imaging are possible.
There is an XYZ stage 12 for adjusting the position of 0.

A portion for detecting and imaging a discharged droplet using the sensor and the CCD includes a sensor light source 16 such as a laser diode (LD) that oscillates a continuous wave (CW) having a wavelength of 680 nm, and a pulse light emission at a wavelength of 808 nm. Light source 17 such as an LD, collimator lenses 14 and 15 provided in front of each light source, a dichroic mirror 13 for aligning the optical axes of the two light sources, and an irradiated droplet 11 at a predetermined magnification. A lens unit 18 for forming an image, a dichroic mirror 19 for wavelength-separating light from the lens unit 18, and a CCD imaging unit 21
And a two-dimensional galvanometer mirror unit 20 for changing the imaging position of the CCD imaging unit, and a two-dimensional optical sensor unit 22 having a light-receiving surface divided into four parts.

As the light source 16 of the optical sensor unit 22, a halogen lamp or LED other than a laser diode (LD) can be used as long as the light amount is sufficient for the sensitivity of the sensor. In the present embodiment, the light from the light source 16 is aligned with the light from the LD 17 as the light source of the CCD imaging unit 21 by the dichroic mirror 13 via the collimator lenses 14 and 15, respectively. Is irradiated. After being imaged at a predetermined magnification by the lens unit 18, the wavelength is separated by the dichroic mirror 19, so that the evaluation of the droplet image by the CCD and the evaluation of the ejection stability by the optical sensor can be performed simultaneously.
Further, by driving the two-dimensional galvanometer mirror unit 20 provided in front of the CCD imaging unit 21 in synchronization with the pulse emission of the light source 17, the shape of the same liquid droplet that changes with time is formed as one CCD image. It is configured to be able to take pictures.

As a part for performing overall control, there are a personal computer (PC) 2, a display 1 connected to the PC, and a PCI interface unit 3 of the PC.
A mirror driving circuit 4 for changing the angle of the galvanometer mirror unit 20; a video capture board 5 for receiving an image captured by the CCD imaging unit 21;
Sensor signal processing circuit 6 for processing signals from the printer, a head drive circuit 7 for driving the inkjet head 10 to discharge droplets, and a head for driving the XYZ stage 12 to change the passage position of the discharged droplets An alignment circuit 8 and a laser drive circuit 7 for controlling light emission timings of the light sources 16 and 17 are provided.

Hereinafter, the operation of this embodiment will be described in order.
First, the PC 2 gives the head drive circuit 7 ejection conditions such as nozzles, ejection cycles, drive voltages and their waveforms, and if there is an order, their sequences, etc., according to the inkjet head 10 to be used. The inkjet head 10 is driven in accordance with the conditions, and the ejection of the droplet is started. Next, the laser drive circuit 9 causes the light source 16 to emit light under APC control, and the head alignment circuit 8 moves the XYZ stage so that the droplet passes through a position where the optical sensor unit 22 can detect.

At this time, the sensor output signal processing circuit 6 is always in a standby state, and starts operation with the detection of the first droplet by the optical sensor unit 22 or the ejection cycle determined by the head drive circuit 7 as a trigger. I do. As the operation mode, two modes for outputting information on the speed and the ejection direction of the droplet are prepared. Then, these signals are transmitted to the PC 2 via the PCI bus, and the information of all the droplets is graphed and displayed on the display 1.

When information is obtained by changing the distance between the droplet and the ink jet head, the XYZ stage 12 is moved by the head alignment circuit 8 to move the ink jet head 10 little by little in the ejection axis direction. The distance from the tip of the ejection nozzle of the inkjet head 10 in the ejection axis direction at the detection position of the optical sensor unit 22 is recorded in units of microns. If the division axis of the optical sensor unit 22 in the ejection direction is different from the ejection direction of the droplet, the mounting angle of the optical sensor is adjusted to perform alignment.

Next, the operation of the CCD image pickup unit will be described. In the present embodiment, the light source 17 emits pulse light, and the image of the droplet is stored in the CCD imaging unit 21 in synchronization with the light emission timing. Three modes are prepared as the light emission timing of the light source 17. That is, the first mode triggered by the ejection cycle and the CC
A second mode in which the synchronization signal that defines the frame period of D is separated and triggered by this signal, and a case where the state of the signal of the sensor output signal processing circuit 6 satisfies a predetermined condition is used as a trigger. This is the third mode.

In any of the modes, the delay time from the trigger to the light emission of the light source 17 can be arbitrarily set from the PC 2 side, and the image of the droplet during the light emission period of the light source 17 is stored in the CCD. However, when it is desired to operate the galvanomirror 20 to accumulate the droplet images side by side or to overwrite the droplet images of a specified number of times, the P
These conditions are also given from C2 to the laser drive circuit 9. The light emission period (pulse width) of the light source 17 is 100 n.
sec or less, and CC by the lens unit 18
The imaging magnification for D can be appropriately selected from about 5 to 40 times according to the purpose.

The image stored in the CCD imaging unit 21 is processed by the PC 2 via the video capture board 5 and displayed on the display 1. The image at this time can select either a single grab or a continuous grab in synchronization with the timing of the pulse emission. When the continuous grab is selected, the information from the optical sensor unit 22 is used together with the DVD-RA by a drive device built in / connected to the PC 2 by setting or selection by the user.
It is stored and held on a writable large-capacity medium such as M, CD-R or MO or a hard disk.

Hereinafter, the optical sensor unit 22 used in the above-described embodiment will be described in more detail.

FIG. 1 shows an optical sensor unit 2 according to this embodiment.
FIG. 2 is a circuit diagram schematically showing a portion related to FIG. As illustrated, the light sensor unit 22 includes a light sensor 221 having a light detection surface such as a photodiode or the like having a light receiving surface that is equally divided into four regions in a matrix and having equal characteristics for each of the divided light receiving surfaces. , Upper and lower 2 each
And a differential current-to-voltage conversion circuit 222 connected to the outputs of the two photodetectors.

The sensor signal processing circuit 6 includes a binarizing circuit, A
/ D converter and FPGA for image processing and various calculations
For transmitting and receiving various data to and from the PCI interface 3.

Here, the operation of the optical sensor unit 22 when detecting a droplet will be described with reference to FIG.

First, when a droplet does not pass, the two current-to-voltage conversion circuits 222 are adjusted to output 0 V, respectively. In this way, the droplet is transparent and D
Even when a large amount of C offset is included, it is possible to accurately detect a change in transmitted light when a droplet passes.
As a result, it is possible to obtain a good output that is not influenced by contrast, and it is also possible to confirm whether or not the amount of received light in each of the divided areas is equal.

As shown in FIG. 1, when the horizontal line dividing the region is set to the X axis and the vertical line is set to the Y axis, the droplet 1
When 1 passes through a position slightly deviated from the center (0) of the X-axis, here on the minus side, two current-voltage conversion circuits 2
From 22, outputs having the same height are obtained as shown in FIG. In FIG. 5A, the first output is the differential output corresponding to the upper two divided areas.
What is detected next is the differential output corresponding to the lower two divided regions.

At this time, when the droplet 11 passes in parallel with the Y axis of the divided area, the two current-to-voltage conversion circuits 222 obtain an output having an equal height proportional to the size of the droplet. Therefore, in consideration of the optical imaging magnification by the lens unit 18 shown in FIG. 4, the size of the droplet can be obtained by comparing the sensor output with a predetermined threshold. On the other hand, the speed of the droplet can be determined by comparing the time from when the sensor output corresponding to the upper region reaches a peak to when the sensor output corresponding to the lower region reaches a peak with a predetermined threshold value.

On the other hand, if the droplet 11 passes obliquely with respect to the Y-axis of the divided area, outputs of different heights are obtained from the two current-voltage conversion circuits 222, and which of the left and right directions is fluctuated. Understand. In the Z-axis (depth) direction, if the light passes through the optical axis of the lens unit 18 while being deviated in the defocus direction, the shape of the output waveform becomes broad. For example, the shape of the output waveform is narrow.

Therefore, in the sensor output signal processing circuit 6,
The width may be obtained by performing a simple binarization process, or a high-speed A
It is also possible to perform one-dimensional image processing in real time with the / D converter and the FPGA, and to extract the peak value and the area value as information. In the present embodiment, these are used together.

FIG. 5B shows a signal waveform obtained by binarizing the sensor output waveform corresponding to the upper region, and FIG. 5C shows a signal waveform obtained by binarizing the sensor output waveform corresponding to the lower region. Is shown. FIG. 5 (d) shows (b) and (c)
It is an example of the waveform which shows the speed information calculated | required from two waveforms.

FIG. 2 shows a modification of the optical sensor unit. The optical sensor unit 22 'of this modification is such that the light receiving surface is equally divided into eight regions in a matrix, and for each divided light receiving surface. An optical sensor 223 having photodetectors such as photodiodes having equal characteristics, and four differential current-voltage conversion circuits 222 connected to the outputs of two upper and lower left and right photodetectors, respectively. And

In this modification, the droplet 11 may be set so as to pass through the center of the X-axis and Y-axis of the divided area. The peak value and the area value may be obtained by simply summing the two outputs corresponding to the upper or lower region inside the FPGA, and detecting whether the output fluctuates to the left or right by comparing the difference between the two outputs. .

Therefore, according to the present modification, the setting of the passage position of the droplet becomes easier while achieving the same function as that of the optical sensor unit shown in FIG.

FIG. 3 shows a modification of the differential current-to-voltage converter 222 used in FIGS. 1 and 2.
The number of resistors used in each current-voltage conversion circuit can be reduced by one. Current-voltage conversion circuit 2 having such a configuration
The same function can be realized in 22 '.

As described above, according to the present embodiment, the following effects can be obtained.

Since the light source can emit a pulse light at every frame period of the CCD to be imaged, images of all the discharged droplets can be photographed by the CCD. If a semiconductor laser or the like is used as the light source, the emission pulse width is 100 nsec.
It is possible to reduce the blur of the shot image and obtain a clear image even when the droplet speed is high. One CCD using a two-dimensional galvanometer mirror
It is also possible to take a plurality of images of the same droplet side by side and photograph them over time, and to compare and evaluate them.

By using a sensor in which the light receiving surface is divided into a matrix, the alignment can be easily performed by monitoring the output of the sensor, and the discharge direction of the droplet can be detected at the same time.

Further, by using the real-time measurement information and the droplet image information by the CCD in combination with the ejection cycle, for example, the output signal of the optical sensor unit is analyzed, and the driving condition in which the ejection becomes unstable is determined. Identify and hold the image of the droplet at that time with the CCD image pickup unit, superimpose and record the droplet image ejected under the driving conditions that make the ejection unstable, or operate the galvanomirror to operate the same droplet This makes it possible to perform detailed evaluation analysis that cannot be performed by a conventional device, such as arranging changes over time and photographing them for comparison and evaluation. The embodiment described above has both a function of measuring physical data such as a droplet size, a speed, and a discharge direction by a region-divided optical sensor unit, and a function of imaging a droplet image by a CCD using pulsed light. The apparatus according to the present invention includes a device having only a function of measuring physical data by an optical sensor unit divided into regions, and a device having only a function of imaging a droplet image by a CCD using pulsed light. It can be considered as an embodiment of a droplet evaluation device.

[Other Embodiments] In the above embodiments, the droplets ejected from the ink jet head have been described as ink. However, the droplets ejected are not limited to ink. Any liquid can be used as long as it can be detected by the device.

The above-described embodiment is particularly provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for causing ink to be ejected even in an ink jet recording system. By using a method in which a change in the state of the ink is caused by energy, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, liquid (ink)
By applying at least one drive signal corresponding to the recorded information and providing a sharp temperature rise exceeding nucleate boiling to an electrothermal transducer arranged corresponding to the sheet or liquid path in which Since heat energy is generated in the electrothermal transducer, film boiling occurs on the heat-acting surface of the ink-jet head, and as a result, air bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis can be formed. It is valid.

By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

The structure of the ink jet head may be a combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above specification. U.S. Pat. No. 4,558,333, which discloses an arrangement in which the heat acting surface is arranged in a bending area;
The configuration described in U.S. Pat. No. 4,459,600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slot is used as a discharge section of an electrothermal transducer for a plurality of electrothermal transducers, and an opening for absorbing pressure waves of thermal energy is discharged. A configuration based on JP-A-59-138461, which discloses a configuration corresponding to each unit, may be adopted.

Another object of the present invention is to supply a storage medium (or a recording medium) in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and a computer (a computer) of the system or the apparatus. It is needless to say that the present invention can also be achieved by a CPU or an MPU) reading and executing the program code stored in the storage medium.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, DVD-ROM, magnetic tape, non-volatile memory card, ROM, etc. can be used.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. By executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. It goes without saying that a case where some or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing is also included.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. Needless to say, the CPU included in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0059]

As described above, according to the first aspect of the present invention having the optical sensor divided into a matrix, the size, speed, discharge direction, etc. of the droplet ejected by the optical sensor are determined. Physical data is accurately obtained in real time.

According to the second aspect of the present invention, in which a pulse light source and an image pickup means are provided and an image of a droplet is picked up by synchronizing ejection of the droplet and irradiation of the pulse light source, the ejection is synchronized with the ejection. In this way, an image of the droplet can be taken and the images can be compared and evaluated.

Further, according to the third aspect of the present invention in which the first and second aspects are combined, data processing is performed by associating physical data of a discharged droplet with an image of the droplet. Therefore, comparative evaluation in various forms is possible.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a portion related to an optical sensor unit.

FIG. 2 is a circuit diagram showing a modification of the optical sensor unit.

FIG. 3 is a circuit diagram showing a modified example of the differential current / voltage conversion circuit.

FIG. 4 is a block diagram illustrating an overall configuration of a discharged droplet evaluation apparatus according to the present invention.

FIG. 5 is a diagram illustrating an example of a signal waveform accompanying the passage of a droplet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Display 2 Personal computer main body 3 PCI interface unit 4 Mirror drive circuit 5 Video capture board 6 Sensor output signal processing circuit 7 Head drive circuit 8 Head alignment circuit 9 Laser drive circuit 10 Inkjet head 11 Droplet 12 XYZ stage 13, 19 Dichroic mirror 14 , 15 Collimator lens 16, 17 Semiconductor laser 18 Imaging lens unit 20 Two-dimensional galvanometer mirror unit 21 CCD imaging unit 22, 22 'Optical sensor unit 221, 223 Area-divided light receiving element 222, 222' Differential current-voltage conversion circuit

Claims (16)

[Claims] 1. A discharge droplet evaluation apparatus for evaluating the stability and reproducibility of droplets discharged by an ink jet method, comprising: an ink jet head for discharging droplets; a light source; An optical sensor having a light receiving surface and a photoelectric conversion element for outputting an electrical signal corresponding to the amount of received light corresponding to each light receiving surface; and an optical system for guiding light emitted from the light source to each light receiving surface of the optical sensor. A signal processing unit that obtains physical data of the droplet from a change in an output signal of the photoelectric conversion element when the droplet ejected from the inkjet head blocks light guided by the optical system; and Data processing means for accumulating and storing the physical data obtained by the processing means and converting the physical data into a form which can be displayed in a predetermined format. Evaluation device. 2. The apparatus according to claim 1, wherein the number of divisions of the light receiving surface of the optical sensor in the vertical and horizontal directions is an even number. 3. The apparatus according to claim 1, wherein the optical system includes a lens that forms an image of the droplet on the light receiving surface at a predetermined magnification. 4. The apparatus according to claim 1, wherein the physical data includes at least one of a size, a speed, and an ejection direction of the droplet. 5. The signal processing unit according to claim 1, wherein the signal processing unit includes a detection unit that detects a difference between output signals of the two photoelectric conversion elements, and a conversion unit that converts the difference into digital data. 5. The discharged droplet evaluation device according to any one of items 1 to 4. 6. The apparatus according to claim 1, further comprising a position alignment unit that can adjust the position of the inkjet head in three dimensions. 7. A droplet evaluation apparatus for evaluating the stability and reproducibility of droplets ejected by an inkjet method, comprising: an inkjet head for ejecting droplets; a light source for irradiating pulsed light; An imaging unit configured to capture an image of a droplet ejected from the inkjet head and irradiated with the pulsed light; an optical system that guides the pulsed light to the imaging unit; Synchronizing means for synchronizing with the drive timing of the inkjet head, and data processing means for accumulating and storing an image of the droplet imaged by the imaging means and converting the image into a form that can be displayed in a predetermined format. A discharge droplet evaluation apparatus characterized by the above-mentioned. 8. The apparatus according to claim 7, wherein the optical system includes a lens that forms an image of the droplet on the imaging unit at a predetermined magnification. 9. The optical system includes a mirror for displacing a position of an image of the droplet formed on the imaging unit by the lens in a predetermined direction, and the data processing unit includes: 9. The apparatus according to claim 8, wherein images of a plurality of droplets formed at different positions of the imaging unit can be displayed simultaneously. 10. The apparatus according to claim 7, wherein the imaging unit captures an image using a CCD. 11. The position of the ink jet head is set at 3
The apparatus according to claim 7, further comprising a position alignment unit that can be adjusted in a dimension. 12. The light emitting period of said pulsed light is 10
0 to 0 nsec or less.
2. The discharged droplet evaluation device according to claim 1. 13. The apparatus according to claim 12, wherein the light source is a semiconductor laser. 14. A droplet evaluation apparatus for evaluating the stability and reproducibility of droplets ejected by an inkjet method, comprising: an inkjet head for ejecting droplets; and a first light having a first wavelength. A first light source for irradiating the second light, a second light source for irradiating a pulsed second light with a second wavelength, and a synchronization unit for synchronizing the irradiation of the second light with a drive timing of the inkjet head. A first optical unit that combines the first and second lights to guide droplets ejected from the inkjet head; a photodetector that outputs an electric signal according to a light receiving surface divided in a matrix and a light receiving amount; An optical sensor having a conversion element corresponding to each light receiving surface; an imaging unit for capturing an image of the droplet; separating light irradiated to the droplet into the first and second lights; The first light is It led to the second
Second optical means for guiding the light to the image pickup means, and physical data of the droplet is obtained from a change in an output signal of the photoelectric conversion element corresponding to the first light guided by the second optical means. A signal processing unit; storing and storing the physical data obtained by the signal processing unit and an image of the droplet imaged corresponding to the second light guided by the second optical unit; And a data processing means for converting the data into a form that can be displayed in a predetermined format. 15. A method for evaluating the stability and reproducibility of droplets ejected by an ink jet method, comprising: a light receiving surface that divides light emitted from a light source into a matrix; A light guiding step of guiding an optical sensor to each light receiving surface of the optical sensor having a photoelectric conversion element corresponding to each light receiving surface to output an electric signal corresponding to the amount of received light, When blocking the light guided by the step, a signal processing step of obtaining physical data of the droplet from a change in an output signal of the photoelectric conversion element, and storing the physical data obtained in the signal processing step And a data processing step of converting the data into a form that can be displayed in a predetermined format. 16. A droplet evaluation method for evaluating the stability and reproducibility of droplets ejected by an ink-jet method, wherein an image of a droplet ejected from an ink-jet head is imaged with pulsed light. A light guiding step for leading to an imaging unit; a synchronization step for synchronizing the irradiation of the pulsed light with a driving timing of the inkjet head; and storing and storing an image of the droplet imaged by the imaging unit, and And a data processing step of converting the data into a form that can be displayed in the format described in (1).