KR-102963924-B1 - Method and device for predicting the result of ink being ejected from an ink ejection device

KR102963924B1KR 102963924 B1KR102963924 B1KR 102963924B1KR-102963924-B1

Abstract

A method for predicting the operation result of an ink dispensing device according to one aspect comprises: a step of obtaining structural information of a nozzle of the ink dispensing device; a step of obtaining physical property information of a piezoelectric element applying an external force to the nozzle and at least one voltage condition applied to the piezoelectric element; and a step of predicting the result of dispensing the ink from the ink dispensing device based on the physical property information of the piezoelectric element and the at least one voltage condition, and based on the displacement of the piezoelectric element calculated and the physical property information of the ink.

Inventors

김준영
신동열

Assignees

경상국립대학교산학협력단

Dates

Publication Date: 20260512
Application Date: 20231019

Claims (15)

As a method for predicting the operation results of an ink dispensing device by a computing device, A step of obtaining structural information of the nozzle of the ink ejection device and determining a nozzle structural region for structural analysis and a fluid region for fluid analysis inside the nozzle; A step of obtaining physical property information of a piezoelectric element applying an external force to the nozzle and at least one voltage condition applied to the piezoelectric element; A step of calculating, by a structural analysis model, the mechanical displacement occurring when a voltage is applied to the piezoelectric element according to the physical property information of the piezoelectric element and the at least one voltage condition; and A method comprising the step of predicting the result of ink being ejected from the ink ejection device by performing fluid analysis according to the calculated mechanical displacement and physical property information of the ink through a fluid-structure interaction region, which is a region where the nozzle structure region and the fluid region meet.
In paragraph 1, The structural information of the above nozzle is, A method comprising a path through which the ink flows inside the nozzle, an outer surface of the nozzle, a piezoelectric element attached to the nozzle, and a design and design dimensions of an ink discharge port through which the ink is discharged.
In paragraph 1, The physical property information of the above piezoelectric element is, A method comprising at least one of the density, piezoelectric constant, elastic constant, and relative permittivity of a material constituting the piezoelectric element.
In paragraph 1, The above voltage conditions are, A method comprising a voltage waveform composed of variables including the time for the voltage to rise from a minimum value to a maximum value, the maximum value, the time for the voltage to maintain the maximum value, and the time for the voltage to fall from the maximum value to the minimum value.
In paragraph 1, The physical property information of the above ink is, A method comprising at least one of the type of ink, density, viscosity according to shear rate, contact angle, and surface tension.
In paragraph 1, The above structural analysis model is, In the structural region of the nozzle, a fixed region where no structural deformation occurs even when voltage is applied to the piezoelectric element and the fluid-structure interaction region are designated, and A method characterized by being a model for analyzing the deformation and displacement of the nozzle and the piezoelectric element.
In paragraph 1, The step of predicting the result of the ink ejection described above is, A step of reflecting the above mechanical displacement into a fluid analysis according to the Navier-Stokes equations through the fluid-structure interaction region; and A method comprising the step of predicting the ink ejection rate and droplet size.
At least one memory; and Includes at least one processor; and The above-mentioned at least one processor is, Structural information of the nozzle of the ink ejection device is obtained to determine the nozzle structural region for structural analysis and the fluid region for fluid analysis inside the nozzle, and Acquiring physical property information of a piezoelectric element applying an external force to the nozzle and at least one voltage condition applied to the piezoelectric element, and Based on the physical property information of the piezoelectric element and the at least one voltage condition, the mechanical displacement occurring when a voltage is applied to the piezoelectric element is calculated by a structural analysis model, and A device for predicting the result of ink ejection from an ink ejection device by performing fluid analysis according to the calculated mechanical displacement and physical property information of the ink through a fluid-structure interaction region, which is a region where the nozzle structure region and the fluid region meet.
In paragraph 8, The structural information of the above nozzle is, A device comprising a path through which the ink flows inside the nozzle, an outer surface of the nozzle, a piezoelectric element attached to the nozzle, and a design and design dimensions of an ink discharge port through which the ink is discharged.
In paragraph 8, The physical property information of the above piezoelectric element is, A device comprising at least one of the density, piezoelectric constant, elastic constant, and relative permittivity of a material constituting the piezoelectric element.
In paragraph 8, The above voltage conditions are, A device comprising a voltage waveform composed of variables including the time for the voltage to rise from a minimum value to a maximum value, the maximum value, the time for the voltage to maintain the maximum value, and the time for the voltage to fall from the maximum value to the minimum value.
In paragraph 8, The physical property information of the above ink is, A device comprising at least one of the type of ink, density, viscosity according to shear rate, contact angle, and surface tension.
In paragraph 8, The above structural analysis model is, In the structural region of the nozzle, a fixed region where no structural deformation occurs even when voltage is applied to the piezoelectric element and the fluid-structure interaction region are designated, and A device characterized by being a model for analyzing the deformation and displacement of the nozzle and the piezoelectric element.
In paragraph 8, The above processor is, A device that incorporates the above mechanical displacement into a fluid analysis according to the Navier-Stokes equations through the fluid-structure interaction region and predicts the ink ejection velocity and droplet size.
A computer-readable recording medium having a program for executing the method according to paragraph 1 on a computer.

Description

Method and device for predicting the result of ink being ejected from an ink ejection device The present disclosure relates to a method and apparatus for predicting the result of ink being ejected from an ink ejection device. An inkjet printing device is a device that prints an image of a predetermined color by ejecting minute droplets of printing ink to a desired location on a printing medium. An inkjet printing device is equipped with an inkjet printhead for ejecting ink. Inkjet printheads can be broadly divided into two types depending on the method of ejecting ink. One is a thermally driven inkjet printhead that uses a heat source to generate bubbles in the ink and ejects the ink by the expansion force of the bubbles, and the other is a piezoelectric inkjet printhead that generates pressure in the ink by utilizing the deformation of an actuator, which is a piezoelectric element, when voltage is applied to the actuator, and ejects the ink by that pressure. Inkjet printing methods using piezoelectric inkjet print heads are being applied to manufacturing processes such as the manufacturing of color filters for liquid crystal displays (LCDs), organic light-emitting diodes (OLEDs), and displays utilizing quantum dots, as well as large-screen industrial printing processes. Inkjet processing is gaining popularity in various fields as a highly economical process method that can deposit fine droplets at desired locations. However, it has limitations, such as restrictions on the inks used and difficulties in setting droplet ejection characteristics. In a piezoelectric inkjet head, ink droplets are ejected according to a supply voltage signal applied to a piezoelectric element. At this time, the supply voltage signal is a signal directly applied to the piezoelectric element, and the magnitude of the voltage and the duration of application affect the ejection characteristics of the ink droplets, namely the dot size and ejection speed of the ejected ink. Therefore, in piezoelectric inkjet printing, ink ejection characteristics cannot be predicted based solely on semiconductor ink management parameters such as viscosity, surface tension, and concentration. If there are defects in ink ejection or the amount of ink ejected is uneven, it may lead to thin film imbalance between pixels, and there is a possibility that ink may be ejected to pixels adjacent to the target pixel. FIG. 1 is a configuration diagram illustrating an example of a device for predicting the result of ink being ejected from an ink ejection device according to one embodiment. FIG. 2 is an exemplary drawing illustrating a method for predicting the operation results of an ink dispensing device according to one embodiment by a computing device. FIG. 3 is a drawing for explaining the modeling of a nozzle structure based on structural information of a nozzle according to one embodiment. FIG. 4 is a diagram illustrating the physical property information of a piezoelectric element according to one embodiment. Figures 5 and 6 are diagrams illustrating voltage conditions applied to a piezoelectric element. Figure 5 is a diagram showing an example of the waveform conditions of the voltage applied to a piezoelectric element. FIG. 6 is an exemplary drawing for explaining the voltage conditions of a voltage waveform according to one embodiment. FIGS. 7a to 7e are exemplary drawings for explaining a method of modeling a nozzle structure based on material property information of a piezoelectric element according to one embodiment. FIGS. 8a to 8e are exemplary drawings for explaining a fluid analysis method of ink according to one embodiment. FIG. 9 is an exemplary drawing for explaining a simulation model that links structural information of a nozzle, physical property information of a piezoelectric element, and physical property information of ink according to one embodiment. FIG. 10 is a diagram showing the execution result of a simulation model that predicted the result of ink being ejected from an ink ejection device according to one embodiment. The terms used in the embodiments have been selected to be as close as possible to currently widely used general terms; however, these may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Additionally, in specific cases, terms have been selected at the applicant's discretion, and in such cases, their meanings will be described in detail in the relevant description section. Therefore, terms used in the specification must be defined not merely by their names, but based on their meanings and the content throughout the specification. When a part of the specification is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, terms such as "~ unit" or "~ module" as used in the specification refer to a unit that processes at least one fu