Inkjet Ejection Pulse Waveform Control for Droplet Landing Precision
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Solution Overview
Problem
Liquid ejecting apparatuses, such as ink jet printers, face challenges in maintaining consistent landing positions of main and satellite liquid droplets when ejecting different types of ink, leading to image quality deterioration due to the tailing effect of resin dispersion type pigment inks.
Innovation Solution
A liquid ejecting apparatus with a driving signal that includes distinct ejection pulses for each ink type, featuring varying potential sections and hold times to control the flying speed of main and satellite droplets, ensuring they land closer together by adjusting the potential inclination and hold ratios in the ejection pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If resin dispersion type pigment ink is ejected using a standard ejection pulse, then the ink can be ejected from the nozzle, but the rear end portion becomes a tailed portion and satellite liquid droplets separate from the main droplet, causing landing position differences that deteriorate image quality
Solution Approach 1:
The ejection pulse is segmented into multiple distinct sections: a first variation section for initial ejection, a hold section for maintaining pressure, and a second variation section with multiple components (first variation component, intermediate hold component, and second variation component) for controlling droplet separation. This segmentation allows precise control over the ejection process to prevent satellite droplet formation while maintaining ejection efficiency.
Solution Approach 2:
The ejection pulse waveform is made dynamic by varying the potential inclination of different components based on ink type. The system adaptively adjusts the pulse characteristics - using gentler slopes for self-dispersion pigment ink and steeper slopes for resin dispersion type pigment ink - to optimize droplet formation and landing position for each ink type.
2Device complexity
If the same ejection pulse is used for both self-dispersion pigment ink and resin dispersion type pigment ink, then the device complexity is reduced, but the landing position difference between main and satellite droplets increases for resin dispersion type ink, deteriorating image quality
Solution Approach 1:
Different ejection pulse characteristics are applied locally to different ink types. The system identifies the ink type and selectively applies appropriate pulse waveforms - with gentler potential inclinations for self-dispersion pigment ink and steeper potential inclinations for resin dispersion type pigment ink - thereby optimizing droplet formation for each specific ink type without requiring complete system redesign.
Solution Approach 2:
The ejection pulse parameters, specifically the potential inclination of the second variation component and the ratio of intermediate hold component potential to hold section potential, are changed based on ink type. This parameter adaptation allows the same hardware to achieve precise landing positions for different ink types by simply modifying the electrical pulse characteristics.
3Manufacturing precision
If the potential inclination of the second variation component is made steeper to improve droplet separation, then satellite droplet formation is reduced for resin dispersion type ink, but the flying speed control becomes less effective, potentially increasing landing position differences
Solution Approach 1:
The ejection pulse employs periodic action through the intermediate hold component, which maintains a specific potential for a defined duration between the first and second variation components. This periodic holding allows the main droplet to separate cleanly from the ink supply while the satellite droplet is still forming, providing temporal control over the droplet separation process and enabling subsequent speed adjustment.
Solution Approach 2:
The first variation section and hold section perform preliminary actions by establishing initial pressure variation and maintaining expansion state before the second variation component acts. This preliminary action prepares the ink for controlled ejection, ensuring that when the steeper second variation component acts, the droplet formation is already optimized, allowing both good separation and speed control to be achieved.
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 configuration reduces the distance between main and satellite droplet landing positions, improving image quality by preventing tailing and ensuring consistent dot formation across different ink types.
Implementation Method 1
a printer using a piezoelectric vibrator as a pressure generation unit
Data Source
AI summary
A potential inclination of the second variation component in the liquid-kind ejection pulse of the first signal is gentler than a potential inclination of the first variation component. A potential inclination of the second variation component in the liquid-kind ejection pulse of the second signal is steeper than the potential inclination of the first variation component. A ratio of the potential of the intermediate hold component to the potential of the hold section is larger in the liquid-kind ejection pulse of the second signal than in the liquid-kind ejection pulse of the first signal.