Liquid Ejecting Head Flow Resistance for Print Quality
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Solution Overview
Problem
High-speed printing leads to increased temperature in the ejecting element substrate, causing ink viscosity to decrease and resulting in overflow from ejection openings, which degrades print quality due to non-ejection defects.
Innovation Solution
The liquid ejecting head design features ejection openings closer to the center with higher flow resistance flow passages, preventing ink overflow by maintaining a sufficient refill speed even at elevated temperatures, thereby suppressing print quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ejecting element substrate is miniaturized and ejection opening arrays are concentrated to achieve high-speed printing, then productivity is improved, but temperature distribution becomes uneven causing ink overflow and print quality degradation
Solution Approach 1:
The patent applies local quality by differentiating flow passage designs based on their spatial location. Central flow passages are designed with smaller cross-sectional areas to increase flow resistance and prevent ink overflow, while peripheral flow passages maintain normal design. This localized structural variation addresses the non-uniform temperature distribution problem without compromising overall printing performance.
2Productivity
If ejection opening arrays are arranged in high concentration to meet high-speed print requirements, then productivity is improved, but heat distribution becomes uneven causing ejection performance degradation
Solution Approach 1:
The patent implements local quality by making flow passage cross-sectional area vary with position. Flow passages closer to the center of the ejecting element substrate have smaller cross-sectional areas, increasing their flow resistance to compensate for higher temperatures and prevent excessive refill rates that would cause overflow and ejection defects.
3Speed
If the refill speed of liquid is increased due to temperature rise, then productivity is improved, but liquid overflows from ejection openings causing non-ejection defects
Solution Approach 1:
The patent applies parameter changes by modifying the flow resistance parameter of specific flow passages. By reducing the cross-sectional area of flow passages in central regions, the flow resistance increases, which counteracts the temperature-induced decrease in liquid viscosity and prevents uncontrolled refill rates that would cause overflow.
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 prevents ink overflow and maintains print quality by ensuring a controlled refill speed through increased flow resistance in central ejection opening arrays, even during high-speed printing.
Implementation Method 1
energy generating elements for generating energy used for ejection of the liquids from the ejection openings
Data Source
AI summary
There are provided a liquid ejecting head, an ejecting element substrate and a liquid ejecting apparatus that can suppress degradation in print quality. Therefore in an ejecting element substrate arranged the closest to the center of a support member, a flow resistance of a flow passage corresponding to an ejection opening of an ejection opening array arranged the closest to the center of the ejecting element substrate is made high.