Liquid Ejection Head Interface Stability Control
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Solution Overview
Problem
Existing liquid ejection technologies face instability in the interface formation between ejection and bubble generation media, leading to variations in droplet composition and ejection performance, which affects the quality of the output product.
Innovation Solution
A liquid ejection head design that controls the interface formation distance and position relative to the ejection orifice, utilizing parallel laminar flows of liquids with adjusted flow rates and viscosities to maintain a stable interface, ensuring consistent ejection operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the interface formation distance and position are not controlled, then the structure is simpler, but the interface stability between ejection and bubble generation media deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-establishing the interface formation distance and position between the ejection medium and bubble generation medium before the ejection process begins. The liquid channel is designed with specific geometric parameters that pre-determine the interface position, ensuring stable interface formation occurs automatically during operation without requiring active control during the ejection process itself.
Solution Approach 2:
The patent employs parameter changes by optimizing the geometric parameters of the liquid channel, including the interface formation distance, channel width, and height. By carefully selecting these parameters, the patent achieves stable interface formation between two liquids with different viscosities and flow rates, resolving the contradiction between simplicity and reliability.
2Productivity
If different liquids with different viscosities and flow rates are used, then the ejection performance can be optimized, but the interface stability between liquids deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the geometric parameters of the liquid channel (width, height, length) to compensate for the different viscosities and flow rates of the two liquids. The interface formation distance is specifically designed to account for the viscosity ratio between the ejection medium and bubble generation medium, allowing different liquid properties to coexist with stable interface formation.
Solution Approach 2:
The patent employs hydraulic principles by designing the liquid channel to utilize the natural flow characteristics of two immiscible liquids. The channel geometry is optimized to maintain laminar flow and stable interface between liquids with different rheological properties, using the liquids' own flow dynamics rather than external control mechanisms.
3Manufacturing precision
If the interface position is not at the appropriate location relative to the ejection orifice, then the manufacturing is simpler, but the droplet composition consistency deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-positioning the interface formation location at a specific distance from the ejection orifice during the design phase. This predetermined interface position ensures that the droplet composition remains consistent during ejection, as the interface is already in the correct location before the ejection process begins, eliminating the need for active positioning control.
Solution Approach 2:
The patent employs local quality by creating a specific zone in the liquid channel where the interface forms at a predetermined position. This localized interface formation zone is designed with specific geometric characteristics that ensure consistent droplet composition at the ejection orifice, while other parts of the channel have different characteristics optimized for their specific functions.
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 ensures a stable and fine ejection operation by forming a stable interface at the appropriate position and length, reducing variations in droplet composition and improving the quality of the output product.
Implementation Method 1
controls the interface formation distance and position relative to the ejection orifice, utilizing parallel laminar flows of liquids with adjusted flow rates and viscosities to maintain a stable interface
Implementation Method 2
a liquid as an ejection medium and a liquid as a bubble generation medium are brought into contact with each other at an interface and the ejection medium is ejected by means of growth of a bubble generated in the bubble generation medium by applying thermal energy
Data Source
Figure 1
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AI summary
A liquid ejection head (1) includes a liquid channel (13) through which a first liquid (31) and a second liquid (32) flow, a pressure generation element (12) that pressurizes the first liquid (31) and an ejection orifice (11) through which to eject the second liquid (32) in a direction crossing a direction of the flow of the first liquid (31) and the second liquid (32) via the pressurization. A distance in the direction of the flow from a position in the liquid channel (13) at which the first liquid (31) and the second liquid (32) merge to the ejection orifice (12) is greater than an interface stabilization distance in the direction of the flow from a position at which the first liquid (31) and the second liquid (32) contact each other to a position at which a stable interface is obtained between the first liquid (31) and the second liquid (32).