Liquid Ejecting Head Circulation Channel Inertance Design
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Solution Overview
Problem
Ink jet type recording apparatuses face issues with ink thickening at the nozzle opening due to vaporization, leading to variations in ejection characteristics and efficiency, with existing solutions either discarding ink uneconomically or inadequately preventing thickening.
Innovation Solution
A liquid ejecting head with a pressure generating chamber, nozzle opening, and a flow channel for circulation, where the inertances of the supply channel, nozzle opening, and flow channel satisfy specific relationships, allowing for efficient ejection and circulation of ink to maintain fresh ink at the nozzle opening, preventing thickening and maintaining ejection characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ink is circulated through a flow channel to prevent thickening, then ink fresh state is maintained, but ejection efficiency decreases due to reduced ink amount at nozzle opening
Solution Approach 1:
The patent applies parameter changes by precisely controlling the inertance values of the supply channel (Ms) and circulation channel (Mc) to satisfy specific mathematical relationships. By adjusting these hydraulic parameters, the system optimizes the balance between ink circulation for freshness and sufficient ink supply for ejection efficiency, resolving the contradiction through quantitative parameter optimization rather than qualitative changes.
Solution Approach 2:
The patent utilizes hydraulic principles by introducing a circulation channel with controlled inertance to manage ink flow dynamics. The hydraulic design allows ink to be diverted for circulation while maintaining adequate pressure and flow to the nozzle opening, using fluid mechanics to balance circulation benefits against ejection requirements.
2Reliability
If ink is discarded to maintain fresh state at nozzle opening, then ejection characteristics are maintained, but economic waste occurs
Solution Approach 1:
The patent implements a circulation recovery system where ink that would otherwise be discarded is instead redirected through a circulation channel back to the reservoir. This allows continuous reuse of ink while maintaining its fresh state through controlled circulation, eliminating waste while preserving ejection characteristics.
Solution Approach 2:
The circulation system enables continuous useful action by constantly moving ink through the circulation channel to prevent thickening, ensuring ink at the nozzle opening remains in a fresh state without interruption. This continuous circulation replaces the periodic discarding approach with an ongoing recovery and reuse process.
3Stability of the object's composition
If vibration is applied to suppress ink thickening, then some thickening prevention is achieved, but sufficient prevention is difficult and ink is still wasted
Solution Approach 1:
The patent replaces the vibration approach with a hydraulic circulation solution. By using controlled ink flow through the circulation channel with specific inertance characteristics, the system achieves effective thickening prevention through continuous renewal of ink at the nozzle opening, which is more reliable than vibration and prevents ink waste through recovery.
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 effectively suppresses ink thickening, maintains ejection characteristics, and prevents economic waste by circulating ink through the flow channel, ensuring stable and long-lasting performance.
Implementation Method 1
a pressure generating unit that generates a variation in pressure in the pressure generating chamber
Implementation Method 2
a flow channel for circulation that is formed in the nozzle opening side rather than the pressure generating chamber and separates a part of the liquid discharged from the pressure generating chamber
Data Source
AI summary
A liquid ejecting head includes: a pressure generating chamber to which liquid is supplied through a liquid supply channel; a pressure generating unit that generates a variation in pressure in the pressure generating chamber; a nozzle opening that ejects the liquid discharged from the pressure generating chamber according to the variation in pressure to the outside; and a flow channel for circulation that is formed in the nozzle opening side rather than the pressure generating chamber and separates a part of the liquid discharged from the pressure generating chamber. When Ms, Mn, and Mc each are inertances of the liquid supply channel, the nozzle opening, and the flow channel for circulation, a relationship of Ms≧(1/Mn+1/Mc)−1 is established.