Liquid Jetting Head Diffusion Bonding Air Elimination
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Solution Overview
Problem
Existing liquid jetting heads face issues with air remaining in pressure chambers, leading to poor ink jetting performance due to inadequate bonding of plates, which results in gaps and air absorption of pressure, hindering efficient ink ejection.
Innovation Solution
A liquid jetting head design that incorporates a channel unit with pressure chambers and channel plates made of metal, along with a piezoelectric actuator, where a space is formed in the overlapping areas to ensure secure bonding without gaps, using diffusion-bonding and grooves to concentrate pressing force and prevent air entrapment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plates are diffusion-bonded together without forming spaces in overlapping areas, then bonding strength is improved, but gaps may form around pressure chambers causing air entrapment and poor jetting performance
Solution Approach 1:
The patent applies local quality by forming spaces only in specific overlapping areas where partition walls are located, while maintaining solid bonding in other regions. This localized modification allows pressing force to concentrate on critical bonding areas without creating gaps that would compromise overall structural integrity or cause air entrapment.
Solution Approach 2:
The patent introduces a new dimension of consideration by forming spaces in the overlapping areas of stacked plates, specifically in regions that would traditionally be solid. This three-dimensional structural modification allows for better force distribution and prevents gap formation without sacrificing bonding strength.
2Area of stationary object
If pressing force is distributed uniformly across all plate surfaces, then bonding area is maximized, but pressing force is not sufficiently transferred to base plate in vicinity of partition wall surfaces
Solution Approach 1:
The patent applies local quality by creating spaces in overlapping areas, which causes the pressing force to concentrate on specific regions including the base plate in the vicinity of partition wall surfaces. This localized force concentration ensures adequate bonding in critical areas while maintaining overall bonding area.
Solution Approach 2:
The patent segments the plate structure by forming spaces in overlapping areas, which divides the force transmission path into different regions. This segmentation allows the pressing force to be effectively transmitted to the base plate in critical areas while maintaining bonding across the entire bonding area.
3Strength
If adhesive is applied to bond stacked plates, then bonding is achieved, but adhesive may flow into ink channels to narrow or block them
Solution Approach 1:
The patent extracts the bonding function from the adhesive-based approach and implements it through diffusion-bonding of metal plates. By removing the adhesive layer entirely and using direct diffusion bonding, the patent eliminates the risk of adhesive flowing into ink channels while maintaining strong bonding between plates.
Solution Approach 2:
The patent replaces the chemical bonding mechanism of adhesive with a mechanical/physical bonding mechanism of diffusion-bonding. This substitution eliminates the harmful effect of adhesive flow into channels while achieving equivalent or superior bonding strength through controlled diffusion and pressing processes.
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 effectively eliminates gaps around pressure chambers, preventing air from entering and improving ink jetting performance by ensuring secure bonding and stable deformation of the piezoelectric actuator, thus enhancing the reliability and efficiency of ink ejection.
Implementation Method 1
a piezoelectric actuator which selectively changes volumes of the pressure chambers and which has a vibration plate made of metal and diffusion-bonded on the other surface of the pressure chamber plate to cover the pressure chambers, a piezoelectric layer arranged in the vibration plate on a side opposite to the pressure chambers
Implementation Method 2
a vibration plate made of metal and diffusion-bonded on the other surface of the pressure chamber plate
Data Source
AI summary
An ink-jet head includes a channel unit and a piezoelectric actuator. The channel unit has a plurality of plates made of metal and including a cavity plate which is made of metal and in which a plurality of pressure chambers are formed and a supply plate which is made of metal and in which holes communicating with the pressure chambers respectively are formed, and the plates are diffusion-bonded with each other. The piezoelectric actuator has a vibration plate which is diffusion-bonded with the cavity plate. A groove is formed in a partition wall defining the pressure chambers or in an area overlapping the partition wall of the vibration plate, the cavity plate, and the supply plate. There is provided a liquid jetting head in which air hardly remains in the pressure chambers, and deterioration of jetting performance by the air is suppressed.