Droplet ejection analysis device, droplet ejection analysis system, droplet ejection analysis method and program

Abstract

This invention provides a droplet ejection analysis device, a droplet ejection analysis system, a droplet ejection analysis method, and a program that can statistically analyze droplet ejection by a droplet ejection unit and lead to improvements in droplets and conditions related to droplet ejection. [Solution] The droplet ejection analysis device 30 includes an acquisition unit 311 that acquires image data of droplets ejected by the droplet ejection unit 20 from the imaging unit 10, an image processing unit 312 that acquires data for each droplet by performing image processing on the image data, a data analysis unit 313 that performs analysis processing based on the particle size data of each droplet, and a display control unit 315 that displays the analysis results of the data analysis unit 313 as statistical data on the display unit 41.

Description

Technical Field

[0001] The present invention relates to a droplet ejection analysis device, a droplet ejection analysis system, a droplet ejection analysis method, and a program.

Background Art

[0002] Conventionally, a droplet ejection device including a droplet ejection unit that ejects droplets toward a ejection target is known. The droplets ejected by the droplet ejection unit are roughly classified into two types: main droplets and satellites. Satellites are smaller than main droplets. Satellites may become mist that floats in the air without landing on the ejection target due to the influence of the atmosphere or the like, and may cause ejection failure by adhering to the nozzle opening surface of the droplet ejection unit. Since the generation situation of satellites changes according to conditions such as the physical properties of the liquid and ejection parameters, it is preferable to set conditions under which satellites are hardly generated as much as possible.

[0003] Therefore, for example, Patent Document 1 describes a droplet observation device that images droplets ejected by a droplet ejection unit using a drop watcher and measures the volume, ejection speed, angle, etc. of the droplets.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the invention of Patent Document 1 only determines whether each droplet is flying normally, and is not configured to be able to examine the conditions of the physical properties of the liquid and ejection parameters under which satellites are statistically unlikely to occur.

[0006] This invention has been made in view of the above circumstances. Its purpose is to provide a droplet ejection analysis device, a droplet ejection analysis system, a droplet ejection analysis method, and a program that can statistically analyze the ejection of droplets by a droplet ejection unit and lead to improvements in droplets and conditions related to droplet ejection. [Means for solving the problem]

[0007] To solve the above problems, the invention described in claim 1 is a droplet ejection analysis device, An acquisition unit acquires image data of the droplets ejected by the droplet ejection unit from the imaging unit, An image processing unit that acquires data for each droplet by performing image processing on the aforementioned image data, A data analysis unit performs analytical processing based on the particle size data of each droplet, A droplet dispensing analysis apparatus comprising: a display control unit that displays statistical data based on the analysis results of the data analysis unit on a display unit; and a droplet dispensing analysis apparatus comprising: a display control unit that displays statistical data based on the analysis results of the data analysis unit on a display unit.

[0008] The invention described in claim 2 is a droplet ejection analysis device according to claim 1, The data analysis unit calculates the particle size of each droplet based on the data of each droplet acquired by the image processing unit. The display control unit causes the display unit to display a histogram based on the frequency distribution table of droplet particle sizes created by the data analysis unit during the analysis process.

[0009] The invention described in claim 3 is a droplet ejection analysis device according to claim 1, The data analysis unit calculates the liquid volume of each droplet based on the data of each droplet acquired by the image processing unit. The display control unit causes the display unit to display a graph showing the liquid volume for each droplet size.

[0010] The invention described in claim 4 is a droplet ejection analysis device according to claim 1, The image processing unit includes a storage unit that stores the data of each droplet acquired by the image processing unit as table data.

[0011] The invention described in claim 5 is a droplet ejection analysis device according to claim 1, The display control unit causes the main droplet analysis result and the satellite analysis result from the data analysis unit to be displayed separately on the display unit.

[0012] The invention described in claim 6 is a droplet ejection analysis device according to claim 1, The data analysis unit calculates the droplet's reach based on the droplet's discharge velocity and particle size. The display control unit causes the display unit to display a graph showing the relationship between the distance reached by the droplet and the volume of liquid.

[0013] The invention described in claim 7 is a droplet ejection analysis device according to claim 6, The data analysis unit sets droplets whose reach is less than a predetermined value as estimated mist, The display control unit highlights the region in the graph where the distance reached is less than the predetermined value.

[0014] The invention described in claim 8 is a droplet ejection analysis device according to claim 7, The droplet dispensing unit is a droplet dispensing head equipped with a piezoelectric element that deforms in response to a drive signal to impart pressure fluctuations to the liquid and dispense droplets, The display control unit causes the display unit to display a graph showing the estimated amount of mist for each voltage of the drive signal.

[0015] The invention described in claim 9 is a droplet dispensing analysis system, A droplet ejection analyzer according to any one of claims 1 to 8, A droplet dispensing unit that dispenses droplets onto the target object, An imaging unit for imaging the ejection of droplets by the aforementioned droplet ejection unit, The system includes a display device that performs a desired display under the control of the display control unit.

[0016] The invention described in claim 10 is, A droplet ejection analysis method using a droplet ejection analysis device, An acquisition step of acquiring image data of droplets ejected by a droplet ejection unit from an imaging unit; An image processing step of acquiring data of each droplet by performing image processing on the image data; A data analysis step of performing analysis processing based on data of the particle size of each droplet; A display control step of causing a display unit to display statistical data based on the analysis result of the data analysis step, and comprising:

[0017] The invention according to claim 11 is a program, causing a computer of a droplet ejection analysis device to function as an acquisition unit that acquires image data of droplets ejected by a droplet ejection unit from an imaging unit, an image processing unit that acquires data of each droplet by performing image processing on the image data, a data analysis unit that performs analysis processing based on data of the particle size of each droplet, and a display control unit that causes a display unit to display statistical data based on the analysis result of the data analysis unit.

Effect of the Invention

[0018] According to the present invention, the ejection of droplets by a droplet ejection unit can be statistically analyzed and connected to the improvement of the droplets and the conditions related to the ejection of droplets.

Brief Explanation of Drawings

[0019] [Figure 1] It is a schematic configuration diagram of a droplet ejection analysis system. [Figure 2] It is a block diagram of a droplet ejection analysis system. [Figure 3] It is an example of table data of droplets. [Figure 4] It is an example of a graph showing a deceleration model of droplets based on the equation of motion for each particle size. [Figure 5] the It is an example of a histogram of the particle size and number of droplets. [Figure 6] It is an example of a graph of the particle size and liquid volume of droplets. [Figure 7]This is an example of a graph showing the frequency distribution of droplet travel distances. [Figure 8] This is an example of a contour plot showing droplet velocity and estimated mist volume. [Figure 9] This is a flowchart of the droplet ejection analysis process. [Modes for carrying out the invention]

[0020] The following description illustrates one or more embodiments of the present invention with reference to the drawings. The effects and features of the embodiments of the present invention will be understood from the following detailed description and drawings. The following detailed description and drawings are provided for illustrative purposes only and do not limit the scope of the present invention.

[0021] [Overall Configuration of the Droplet Dispensing Analysis System] Figure 1 is a schematic diagram of a droplet ejection analysis system (hereinafter referred to as the analysis system) 100 equipped with a droplet ejection analysis device (hereinafter referred to as the analysis device) 30 according to this embodiment. Figure 2 is a block diagram showing the functional configuration of the analysis system 100 according to this embodiment.

[0022] The analysis system 100 comprises an imaging unit 10, a droplet ejection unit 20, an analysis device 30, and a display device 40.

[0023] (Imaging unit) The imaging unit 10, under the control of the control unit 31 (described later), captures images of droplets ejected by the droplet ejection unit 20 and transmits the image data to the analysis device 30. The imaging unit 10 includes a light-emitting unit 11 and an imaging unit 12. The light-emitting unit 11 is, for example, a strobe, and under the control of the control unit 31, it emits light in synchronization with the droplet ejection cycle of the droplet ejection unit 20. The imaging unit 12 is, for example, a CCD (Charge Coupled Device) camera, and it receives the light emitted by the light-emitting unit 11 and captures images of the droplets.

[0024] Note that the light-emitting unit 11 is not limited to a strobe; it may also be an LED (Light Emitting Diode), etc. Similarly, the imaging unit 12 is not limited to a CCD camera; it may also be a CMOS (Complementary Metal Oxide Semiconductor) camera, etc. However, using a strobe for the light-emitting unit 11 and a CCD camera for the imaging unit 12 is preferable because it allows for the construction of the imaging unit 10 at a relatively low cost.

[0025] (Droplet discharge part) The droplet ejection unit 20 is an inkjet head that ejects ink droplets, comprising, for example, a plurality of pressure chambers for storing ink, piezoelectric elements provided on the walls of the pressure chambers, and a plurality of nozzles, each communicating with the plurality of pressure chambers and having an opening on the lower surface of the droplet ejection unit 20. When the droplet ejection unit 20 receives a drive signal from the control unit 31 to deform the piezoelectric elements, the pressure chambers deform, changing the pressure inside the pressure chambers and ejecting droplets from the nozzles.

[0026] Furthermore, the droplets ejected by the droplet ejection unit 20 are not limited to ink droplets; any droplets such as pretreatment liquid or coagulant may be ejected. Also, the configuration by which the droplet ejection unit 20 ejects droplets is not limited to those described above.

[0027] (Droplet discharge analysis device) The analysis device 30 is connected to the imaging unit 10, the droplet ejection unit 20, and the display device 40 via a network (not shown). The analysis device 30 performs various analysis processes based on the image data of droplets ejected by the droplet ejection unit 20, which is captured by the imaging unit 10. The analysis device 30 includes a control unit 31, a storage unit 32, and a communication unit 33.

[0028] {control unit} The control unit 31 is a processor (computer) that has a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), etc., and controls all parts that make up the analysis device 30 and the analysis system 100. The CPU reads programs such as application programs stored in the memory unit 32, loads them into RAM, and executes various processes by running the programs. In particular, the control unit 31 functions mainly as the acquisition unit 311, image processing unit 312, data analysis unit 313, estimation unit 314, and display control unit 315 when the CPU executes the programs.

[0029] <Acquisition part> The acquisition unit 311 acquires image data of the droplets captured and transmitted by the imaging unit 12. In addition, when information necessary for data analysis by the data analysis unit 313 (such as the droplet's mass, mass density, charge, air's viscous resistance, the vector quantity of the flow velocity vector field, the vector quantity of the electric field, and the distance to the discharge target) is input to the operation input unit 42, which will be described later, the acquisition unit 311 acquires this information.

[0030] <Image Processing> The image processing unit 312 performs image processing on the image data acquired by the acquisition unit 311 from the imaging unit 10 to obtain data such as the particle size and velocity of each droplet. The image processing unit 312 then creates table data, as shown in Figure 3, which includes information such as the particle size and velocity of each droplet, whether it was ejected from one of the nozzles, and whether the droplet is a main droplet or a satellite, and stores it in the storage unit 32.

[0031] <Data Analysis Department> The data analysis unit 313 performs various analysis processes based on data such as droplet size and velocity obtained by the image processing unit 312.

[0032] For example, the data analysis unit 313 creates a frequency distribution table of droplet particle sizes by setting particle size classes based on the number and range of data, based on the table data created by the image processing unit 312.

[0033] Furthermore, the flight distance of droplets ejected from the droplet ejection unit 20 changes as they decelerate in response to air resistance, and this effect of air resistance is greater when the droplet size is smaller. Also, the flight distance of droplets ejected from the droplet ejection unit 20 is shorter when the ejection speed is slower.

[0034] In detail, the deceleration of a liquid droplet can be represented by the following model equation using the equation of motion. Equation (1) is the model equation without considering gravity, and equation (2) is the model equation with gravity considered. In the following, k is the viscous resistance of the air, v0 is the velocity (initial velocity) of the liquid droplet, and m is the mass of the liquid droplet.

[0035]

number

[0036]

number

[0037] Figure 4 shows the droplet deceleration models for different particle sizes, using model equations (1) and (2), respectively. As shown in Figure 4, there is almost no difference in the calculated droplet travel distance whether gravity is considered or not. Therefore, in the following, the flight distance based on equation (1), which does not consider gravity, will be used as the travel distance.

[0038] Here, since the droplet is spherical, if η is the viscosity coefficient of air and r is the radius of the droplet, the viscous resistance k of the air can be expressed as shown in equation (3) below.

[0039]

number

[0040] Furthermore, if p is the mass density of the liquid, the mass m of the droplet can be expressed as shown in equation (4) below.

[0041]

number

[0042] Substituting equations (3) and (4) into equation (1) yields equation (5), which is the equation for dsup: droplet reach distance, including droplet velocity v0 and particle size (radius r). Therefore, the data analysis unit 313 can calculate the droplet reach distance based on the droplet velocity and particle size.

[0043]

number

[0044] Note that the equations of motion are not limited to those shown in equations (1) and (2), but may also be expressed using equation (6) below, which utilizes information on the electrical conductivity and dielectric constant of the liquid, the airflow, and the electric field. However, in equation (6), V(x) is the vector quantity of the airflow velocity vector field, E(x) is the vector quantity of the electric field in the space where the droplet is ejected, and q is the charge of the droplet.

[0045]

number

[0046] <Estimation part> The estimation unit 314 determines whether a droplet will land on the target or scatter into the air based on a preset distance from the bottom surface of the droplet dispensing unit 20 to the target of dispensing, and the reach distance of each droplet calculated by the data analysis unit 313.

[0047] In detail, if the droplet's reach is less than the set value, the droplet will not hit the target and will instead become mist that scatters into the air. On the other hand, if the droplet's reach is less than the set value, the droplet will hit the target. Thus, the estimation unit 314 determines whether the droplet will hit the target or scatter into the air without hitting it, based on the relationship between the droplet's reach and the set value.

[0048] Furthermore, if a transport speed for the discharged object is set, the estimation unit 314 takes into account the influence of that transport speed to estimate the impact position on the discharged object.

[0049] <Display Control Section> The display control unit 315 transmits a predetermined display control signal to the display device 40 based on various programs and data stored in the storage unit 32, causing the display unit 41 (described later) to display statistical data based on the analysis results of the data analysis unit 313.

[0050] For example, the display control unit 315 creates a histogram, as shown in Figure 5, with particle size on the X axis and the number of droplets on the Y axis, based on the frequency distribution table created by the data analysis unit 313, and displays it on the display unit 41. Figure 5 shows that the distribution of droplet particle size shows two peaks: one for the main droplet and one for the satellite. By displaying a histogram like the one in Figure 5 on the display unit 41, the user can intuitively recognize the distribution of particle size between the main droplet and the satellite.

[0051] Furthermore, the display control unit 315 creates a graph, as shown in Figure 6, with particle size on the X axis and liquid volume for each particle size on the Y axis, based on the analysis results of the data analysis unit 313, and displays it on the display unit 41. Figure 6 shows the liquid volume of the main droplet and satellite droplets. By displaying a graph like Figure 6 on the display unit 41, the user can intuitively recognize whether the droplet dispensing unit 20 is dispensing a sufficient amount of main droplets.

[0052] Furthermore, when the data analysis unit 313 calculates the reach of each droplet, the display control unit 315 may create a frequency distribution of the droplet reach calculated by the data analysis unit 313, as shown in Figure 7, and display it on the display unit 41.

[0053] In particular, if a set value for the distance between the lower surface of the droplet discharge unit 20 and the target of discharge is set, the display control unit 315 may highlight the region in the frequency distribution that is less than the set value, as shown in Figure 7. This configuration makes it possible to visualize the estimated amount of mist (estimated mist amount), which is droplets that do not land on the target of discharge.

[0054] Furthermore, in this configuration, the display control unit 315 may display a contour plot on the display unit 41, as shown in Figure 8, with the X-axis representing the voltage of the drive signal (i.e., the droplet velocity) and the Y-axis representing the estimated mist volume. From the results shown in Figure 8, it can be seen that the estimated mist volume increases as the set value of the distance between the lower surface of the droplet discharge unit 20 and the discharge target increases. It can also be seen that, up to a predetermined value, the estimated mist volume increases as the discharge voltage increases and the droplet velocity increases.

[0055] Furthermore, it is particularly preferable that the display control unit 315 displays contour plots on the display unit 41 for comparison when, for example, the physical properties of the liquid or the discharge parameters are different, as this allows for comparison and examination of which condition can better suppress mist generation.

[0056] Alternatively, the display control unit 315 may display the analysis results of the main droplet and the satellite separately on the display unit 41.

[0057] (Storage part) The storage unit 32 includes an HDD (Hard Disk Drive) or non-volatile semiconductor memory. The storage unit 32 stores various programs and data executed by the control unit 31. The storage unit 32 also stores table data created by the image processing unit 312 and frequency distribution tables created by the data analysis unit 313. At least a portion of the various programs may be stored in the ROM of the control unit 31.

[0058] (Communications Department) The communication unit 33 is composed of a communication module and the like. The communication unit 33 transmits and receives various signals and data to and from the imaging unit 10, droplet ejection unit 20, and display device 40, which are connected via a network, as well as to other devices.

[0059] (display device) The display device 40 is, for example, a personal computer equipped with a display unit 41, which is a display, and an operation input unit 42, which is an operation input unit such as a keyboard or mouse. The analysis device 30 may also be equipped with a configuration corresponding to the display unit 41 and the operation input unit 42, in which case the analysis system 100 does not need to be equipped with a display device 40.

[0060] [Droplet Discharge Analysis Processing] The sequence of steps in the droplet ejection analysis process in this droplet ejection analysis system 100 will be explained based on the flowchart in Figure 9.

[0061] First, the control unit 31 of the analysis device 30 controls the imaging unit 10 and the droplet ejection unit 20 to cause the imaging unit 10 to image the droplets ejected by the droplet ejection unit 20 under predetermined conditions (step S101).

[0062] The acquisition unit 311 acquires image data from the imaging unit 10 (step S102; acquisition step). The acquisition unit 311 then passes the acquired image data to the image processing unit 312 for image processing (step S103; image processing step).

[0063] For example, the image processing unit 312 measures the dimensions of the main droplet and satellite included in the acquired image data and identifies the nozzle from which they are dispensed. The image processing unit 312 also measures the dispensing speed of a predetermined main droplet and satellite based on a series of consecutive image data. Based on this data, the image processing unit 312 creates table data as shown in Figure 3.

[0064] The data analysis unit 313 performs various data analyses based on the table data created by the image processing unit 312 (step S104; data analysis step). In particular, the data analysis unit 313 calculates the reach of each droplet as needed. Then, the estimation unit 314 estimates the behavior of the droplets based on the reach calculated by the data analysis unit 313 and a preset distance value from the droplet discharge unit 20 to the discharge target (step S105; estimation step).

[0065] When the display control unit 315 receives a display instruction for statistical data from the user via the operation input unit 42, it creates various statistical data as shown in Figures 5 to 8 based on the received instruction, the processing results of the image processing unit 312, and the analysis results of the data analysis unit 313. The display control unit 315 then displays the created statistical data on the display unit 41 (step S106; display control step). Note that the control in step S106 may be performed automatically when the acquisition unit 311 acquires image data from the imaging unit 10, even without receiving an instruction from the operation input unit 42.

[0066] [Effects of the Embodiment] As described above, the analysis device 30 according to this embodiment includes an acquisition unit 311 that acquires image data of droplets discharged by the droplet discharge unit 20 from the imaging unit 10. The analysis device 30 also includes an image processing unit 312 that acquires data for each droplet by performing image processing on the image data. The analysis device 30 also includes a data analysis unit 313 that performs analysis processing based on the particle size data of each droplet. The analysis device 30 also includes a display control unit 315 that displays statistical data based on the analysis results of the data analysis unit 313 on the display unit 41. With this configuration, the statistical occurrence status of satellites is displayed on the display unit 41, and based on this information, improvements can be made to the conditions related to droplets and droplet discharge.

[0067] In the above, an example was disclosed in which an HDD was used as the computer-readable medium for the program according to the present invention, but the invention is not limited to this example. Portable recording media such as CD-ROMs can be used as other computer-readable media. Furthermore, carrier waves can also be used as a medium for providing the data of the program according to the present invention via a communication line. [Explanation of symbols]

[0068] 100 Droplet Dispensing Analysis System 10 Imaging Unit 20 Droplet discharge part 30 Droplet discharge analysis device 311 Acquisition Department 312 Image Processing Unit 313 Data Analysis Department 315 Display Control Unit 32 Storage section 40 Display device 41 Display section

Claims

1. An acquisition unit that acquires image data of droplets ejected by the droplet ejection unit from the imaging unit, An image processing unit that acquires data for each droplet by performing image processing on the aforementioned image data, A data analysis unit performs analytical processing based on the particle size data of each droplet, A droplet dispensing analysis apparatus comprising: a display control unit that displays statistical data based on the analysis results of the data analysis unit on a display unit; and a droplet dispensing analysis apparatus comprising: a display control unit that displays statistical data based on the analysis results of the data analysis unit on a display unit.

2. The data analysis unit calculates the particle size of each droplet based on the data of each droplet acquired by the image processing unit. The droplet ejection analysis apparatus according to claim 1, wherein the display control unit causes the display unit to display a histogram based on a frequency distribution table of droplet particle sizes created by the data analysis unit in the analysis process on the display unit.

3. The data analysis unit calculates the liquid volume of each droplet based on the data of each droplet acquired by the image processing unit. The droplet dispensing analysis apparatus according to claim 1, wherein the display control unit causes the display unit to display a graph showing the liquid volume for each droplet size.

4. The droplet ejection analysis apparatus according to claim 1, further comprising a storage unit that stores data of each droplet acquired by the image processing unit as table data.

5. The droplet ejection analysis apparatus according to claim 1, wherein the display control unit displays separately on the display unit the analysis results of the main droplet and the analysis results of the satellite from the analysis results of the data analysis unit.

6. The data analysis unit calculates the droplet's reach based on the droplet's discharge velocity and particle size. The droplet dispensing analysis apparatus according to claim 1, wherein the display control unit causes the display unit to display a graph showing the relationship between the distance reached by the droplet and the volume of liquid.

7. The data analysis unit sets droplets whose reach is less than a predetermined value as estimated mist, The droplet ejection analysis apparatus according to claim 6, wherein the display control unit highlights the region in the graph where the reach distance is less than the predetermined value.

8. The droplet dispensing unit is a droplet dispensing head equipped with a piezoelectric element that deforms in response to a drive signal to impart pressure fluctuations to the liquid and dispense droplets, The droplet ejection analysis apparatus according to claim 7, wherein the display control unit causes the display unit to display a graph showing the estimated amount of mist for each voltage of the drive signal.

9. A droplet ejection analysis device according to any one of claims 1 to 8, A droplet dispensing unit that dispenses droplets onto the target object, An imaging unit for imaging the ejection of droplets by the aforementioned droplet ejection unit, A droplet ejection analysis system comprising a display device that performs a desired display under the control of the display control unit.

10. A droplet ejection analysis method using a droplet ejection analysis device, The acquisition step involves acquiring image data of the droplets ejected by the droplet ejection unit from the imaging unit, An image processing step to obtain data for each droplet by performing image processing on the aforementioned image data, A data analysis step that performs analytical processing based on the particle size data of each droplet, A droplet dispensing analysis method comprising: a display control step that displays statistical data based on the analysis results of the data analysis step on a display unit.

11. The computer for the droplet dispensing analysis device An acquisition unit acquires image data of the droplets ejected by the droplet ejection unit from the imaging unit. An image processing unit that acquires data for each droplet by performing image processing on the aforementioned image data. A data analysis unit performs analytical processing based on the particle size data of each droplet. A program that functions as a display control unit, which displays statistical data based on the analysis results of the data analysis unit on the display unit.

Images