Resonant EHD Nozzle Driving for Precise Ink Droplet Control
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Solution Overview
Problem
The piezoelectric driving method in inkjet printing is limited by the size of the nozzle and surface tension, restricting the size of ink droplets, while existing electrohydrodynamic (EHD) methods face challenges in improving amplitude gain and response characteristics.
Innovation Solution
A printing device incorporating a resonance circuit with an AC or DC power source, inductors, and capacitors to amplify the voltage applied to the nozzle, enhancing the EHD printing method by matching the switching frequency with the resonance frequency to achieve improved amplitude gain and response characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If piezoelectric driving method is used to discharge ink droplets, then ink droplets can be discharged from the nozzle, but the size of ink droplet is limited due to the size of the nozzle interior diameter and surface tension
Solution Approach 1:
The patent replaces the piezoelectric mechanical pressure system with an electrohydrodynamic electrical field system. By applying high voltage to the nozzle and ground voltage to the lower substrate, an electric field is generated that overcomes surface tension and enables ink droplet discharge without being constrained by nozzle interior diameter, thus expanding the adaptable ink droplet size range while maintaining precision control
Solution Approach 2:
The patent changes the fundamental driving parameter from mechanical pressure (piezoelectric) to electrical field strength (EHD). By controlling the voltage applied to the nozzle and substrate, the system can dynamically adjust the electric field intensity to produce varying ink droplet sizes, thereby improving both precision control and adaptability across different droplet size requirements
2Power
If high voltage is applied to the nozzle in EHD printing method, then ink droplets can be discharged effectively, but the amplitude gain and response characteristic of the voltage applied to the nozzle need to be improved
Solution Approach 1:
The patent introduces a resonance circuit containing inductors and capacitors that resonates at a specific frequency to amplify the voltage signal applied to the nozzle. By tuning the resonance frequency to match the desired operating frequency, the system achieves enhanced amplitude gain and improved response characteristics, making the high voltage application more reliable and controllable
Solution Approach 2:
The patent incorporates feedback control by monitoring the voltage applied to the nozzle and adjusting the resonance circuit parameters accordingly. This feedback mechanism ensures that the amplitude gain and response characteristics remain optimized, maintaining reliable performance when high voltage is applied to discharge ink droplets effectively
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the printing device to discharge ink droplets with improved precision and uniform thickness, reducing system interference and noise, and enhancing the amplitude gain and response characteristics compared to traditional methods.
Implementation Method 1
a resonance circuit connected to the AC power source, including at least one inductor and at least one capacitor, and having a resonance frequency that is the same as the first frequency
Implementation Method 2
In a piezoelectric driving method, when electricity is supplied to a piezoelectric element, a pressure is applied to the ink and the ink droplets are discharged from the nozzle
Implementation Method 3
An electrohydrodynamic (EHD) injection method to overcome this limitation is a method in which the ink droplets are discharged by applying a high voltage to the nozzle and applying a ground voltage to a lower substrate to generate an electric field between the nozzle and the lower substrate
Data Source
AI summary
A printing device includes: an AC power source configured to generate power having a first frequency; a resonance circuit connected to the AC power source, including at least one inductor and at least one capacitor, and having a resonance frequency that is equal to the first frequency; and a nozzle connected to the resonance circuit and configured to discharge an ink droplet onto a substrate.