Liquid Ejection Apparatus Droplet Alignment via Resonance Timing
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Solution Overview
Problem
In liquid ejection apparatuses with multiple ejection openings per channel, droplets often fly in different directions, leading to poor image quality due to the directional difference in droplet ejection.
Innovation Solution
A liquid ejection apparatus with a controller that adjusts the energy application to the pressure chambers to control the ejection period of droplets, ensuring they align properly by using specific inequations for the distance and diameter of ejection openings, and resonance period, thereby aligning droplets from adjacent ejection openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two or more ejection openings are disposed with respect to one individual channel, then the productivity is improved by forming one pixel with multiple droplets, but the droplets fly in directions away from each other causing poor image quality
Solution Approach 1:
The patent utilizes resonance vibration of the liquid column in the pressure chamber to control droplet ejection. By setting the ejection timing to coincide with the resonance period of the individual channel, the liquid column oscillates in a controlled manner, ensuring that multiple droplets ejected from different openings travel in the same direction and form a unified pixel, thereby resolving the directional divergence problem while maintaining multi-droplet pixel formation capability
Solution Approach 2:
The patent employs periodic ejection timing synchronized with the resonance period of the individual channel. The controller is configured to eject droplets at specific periodic intervals that match the natural resonance frequency of the liquid column, creating a rhythmic ejection pattern that ensures consistent droplet trajectories and proper pixel formation from multiple openings
2Device complexity
If the ejection period is not synchronized with the resonance period, then the device complexity is reduced, but the droplets fly in different directions reducing image quality
Solution Approach 1:
The patent incorporates a feedback mechanism where the controller monitors and adjusts the ejection timing based on the resonance period of each individual channel. By detecting the resonance characteristics of the liquid column and synchronizing the ejection timing accordingly, the system automatically compensates for variations in channel dimensions and liquid properties, ensuring precise droplet alignment without requiring complex external control systems
Solution Approach 2:
The system utilizes the inherent resonance properties of each individual channel to self-regulate droplet ejection timing. The liquid column's natural oscillation serves as a self-synchronizing mechanism, where the resonance period automatically determines the optimal ejection interval, eliminating the need for complex external timing control while ensuring precise droplet directional alignment
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 solution effectively aligns droplets from multiple ejection openings, improving image quality by minimizing directional differences in droplet flight, ensuring they form a single pixel correctly.
Implementation Method 1
Ta is a resonance period of the individual channel, and T is an ejection period of ink droplets while one pixel is formed
Data Source
AI summary
A liquid ejection apparatus includes a liquid ejection head including a plurality of ejection opening groups each constituted by two or more ejection openings and each forming one pixel by at least two liquid droplets ejected from the two or more ejection openings; a plurality of individual channels respectively connecting the plurality of ejection opening groups to a plurality of pressure chambers; a nozzle plate through which a plurality of nozzle holes extend; and an energy-applying portion applying energy to liquid in the plurality of pressure chambers, and a controller controlling the energy-applying portion. The controller controls the energy-applying portion in such a manner as to meet the following inequations: 0.85Ta≦T≦0.9Ta or 1.2Ta≦T in a case of p/D≦1.2, and 0.85Ta≦T in a case of p/D>1.2.