Liquid Discharge Head Port Projections for Droplet Separation
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Solution Overview
Problem
Conventional liquid discharge heads struggle to reduce satellite formation effectively for high-definition image quality, particularly when discharging small liquid droplets, as the existing methods do not adequately advance the separation timing of the discharged liquid from the discharge port, leading to elongated droplet tails and degraded image quality.
Innovation Solution
The liquid discharge head incorporates a discharge port design with convex projections that create distinct fluid resistance areas, allowing for earlier separation of the liquid droplet by holding the liquid surface in a high fluid resistance area and pulling it back into the discharge port through lower resistance areas, thereby shortening the droplet tail and reducing satellite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional discharge port design is used, then liquid discharge function is maintained, but satellite formation increases and image quality degrades
Solution Approach 1:
The discharge port is designed with projections that create local variations in fluid resistance. Specifically, certain regions of the discharge port have higher fluid resistance than others, causing the liquid meniscus to be held at specific locations. This local differentiation in resistance properties enables controlled liquid separation and reduces satellite formation without requiring complete redesign of the discharge port structure.
2Power
If liquid droplet separation timing is delayed, then discharge energy is sufficient, but droplet tail elongates and satellites form
Solution Approach 1:
The discharge port projections are configured to preliminarily hold the liquid meniscus at specific positions before complete discharge occurs. This preliminary positioning action creates a predetermined separation point that advances the timing of droplet detachment, allowing the main droplet to separate earlier while maintaining sufficient discharge energy. The projections effectively prepare the liquid column for separation in advance, preventing tail elongation and satellite formation.
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 significantly advances the separation timing of the liquid droplet, resulting in a substantial reduction of satellites and mists that deteriorate image quality, improving the overall image quality by shortening the droplet tail and maintaining the linearity of the droplet trajectory.
Implementation Method 1
a bubble is generated inside a discharge port... the bubble grows... when some time has elapsed following the disappearance of the bubble
Implementation Method 2
a film boiling phenomenon is produced at the surface of the heater by electrifying the heater
Implementation Method 3
impelled by the inertial force of the energy generated by the film boiling, the liquid near the heater is moved... the inertial force also increases the quantity of the liquid that is discharged
Implementation Method 4
the discharged liquid, which can no longer maintain the liquid pillar state, is separated by breaking away, countering the viscosity of the liquid, and becomes a separate liquid droplet
Data Source
AI summary
A liquid discharge head is arranged in a manner that in the cross-section of a discharge port in a liquid discharge direction, the discharge port includes at least one projection that is convex inside the discharge port; a first area, for holding a liquid surface connecting a pillar-shaped liquid that is elongated outside the discharge port; and second areas where a fluid resistance is lower than that in the first area so as to pull the liquid in the discharge port in a direction opposite to the liquid discharge direction. The first area is formed in the direction in which the projection is convex, and the second areas are formed on both sides of the projection.