Liquid Ejection Head Resonance Tuning for Uniform Droplet Velocity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid ejection heads face challenges in maintaining consistent ejection velocity of droplets, leading to variations that affect image quality.
Innovation Solution
The liquid ejection head is designed with specific ratios of angular frequencies and attenuation rates in the individual and partial flow channels to stabilize the natural vibrations of the liquid, ensuring consistent ejection velocity through the use of actuators that apply pressure to the pressurization chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the pulse waveform width is optimized to match the resonance frequency of the liquid in the individual flow channel, then the ejection velocity of the liquid is increased, but the ejection velocity becomes inconsistent across multiple nozzles due to manufacturing variations
Solution Approach 1:
The patent introduces a new design parameter - the angular frequency ratio between partial and individual flow channels (ω2/ω1) - to control and standardize the natural vibration characteristics. By specifying that this ratio falls within a predetermined range, the patent transforms the uncontrollable manufacturing variations into a controlled design parameter, ensuring consistent ejection velocity across multiple nozzles while maintaining high ejection speed.
Solution Approach 2:
The patent exploits the natural vibration of liquid in flow channels to enhance ejection velocity. By designing the partial flow channel's natural vibration frequency (ω2) to be a multiple of the individual flow channel's frequency (ω1), the patent creates constructive interference that amplifies the liquid's natural vibration, thereby increasing ejection velocity without requiring excessive drive signal amplitude.
2Speed
If the natural vibration of liquid in the individual flow channel is utilized to push out liquid, then the ejection velocity is increased, but variations in natural vibration frequency due to manufacturing tolerances cause inconsistencies in droplet ejection
Solution Approach 1:
The patent converts the unreliable manufacturing tolerance issue into a controlled design specification by introducing the angular frequency ratio parameter (ω2/ω1). By requiring this ratio to fall within a predetermined range, the patent ensures that despite manufacturing variations in individual dimensions, the relative relationship between flow channel frequencies remains controlled, thereby ensuring consistent droplet ejection across production batches.
Solution Approach 2:
The patent leverages the natural vibration of liquid in both individual and partial flow channels to enhance ejection reliability. The specific frequency relationship (ω2 = n × ω1) creates a resonant effect that amplifies liquid motion in a predictable and consistent manner, reducing the impact of manufacturing tolerances on ejection consistency.
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
This design reduces variations in ejection velocity, thereby improving image quality by ensuring consistent droplet deposition.
Implementation Method 1
An angular frequency of a natural vibration of the liquid in the individual flow channel is ω1 (rad/s). An angular frequency of a natural vibration of the liquid in the partial flow channel is ω2 (rad/s).
Data Source
AI summary
A liquid ejection head includes a flow channel member and an actuator. The flow channel member includes an individual flow channel that accommodates a liquid. The individual flow channel includes a pressurization chamber, a partial flow channel extending from the pressurization chamber, and a nozzle opening to the outside at an end portion of the partial flow channel on the opposite side from the pressurization chamber. The actuator applies pressure to the pressurization chamber. An attenuation rate of a natural vibration (main vibration) of the liquid in the individual flow channel is γ1 (rad/s). An angular frequency of the main vibration is ω1 (rad/s). An angular frequency of a high-frequency vibration is ω2 (rad/s). n is a positive integer. The following formula is satisfied. 0.95×2n (1+0.32×γ1/ω1)≤ω2/ω1≤1.05×2n(1+0.32×γ1/ω1)