Liquid Discharge Head Flow Control for Air Bubble Removal
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Solution Overview
Problem
Existing liquid discharge heads face issues with air bubbles trapped in pressure chambers, leading to non-discharge or poor discharge due to stagnant areas where acoustic waves cannot reach, causing deviations in liquid volume, speed, and direction.
Innovation Solution
A controlled flow mechanism is implemented using a drive voltage applied to actuators to generate a controlled flow along the inner surface of the nozzle plate, moving air bubbles from stagnant areas to dischargeable positions through controlled liquid flow, optimized by waveform, voltage, and frequency adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acoustic waves are used to discharge liquid from the pressure chamber, then liquid discharge is achieved, but air bubbles in stagnant areas cannot be removed causing non-discharge or poor discharge
Solution Approach 1:
The patent applies dynamic control by varying the drive voltage waveform across different regions of the nozzle plate. Different regions receive different voltage patterns (sine waves, square waves, triangular waves) at different frequencies and amplitudes, creating dynamic fluid motion that disrupts stagnant areas and enables air bubble removal while maintaining reliable liquid discharge.
Solution Approach 2:
The patent implements local quality control by dividing the nozzle plate into multiple regions (first region, second region, third region) with different drive voltage characteristics. Each region is independently controlled with specific waveform, frequency, and amplitude parameters tailored to its location, enabling targeted disruption of stagnant areas while preserving discharge performance in other regions.
2Reliability
If drive voltage is applied to generate controlled flow, then air bubbles are moved from stagnant areas, but liquid volume control and discharge timing must be precisely maintained
Solution Approach 1:
The patent employs periodic action by applying sinusoidal, square, and triangular waveforms at specific frequencies (e.g., 20-100 Hz for first region, 50-200 Hz for second region, 100-300 Hz for third region). These periodic voltage variations create controlled oscillating flows that systematically move air bubbles from stagnant areas while maintaining predictable liquid discharge timing and volume.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying drive voltage characteristics including waveform type, frequency, amplitude, and duty cycle across different regions and time periods. This enables precise control of fluid motion to remove air bubbles while maintaining accurate liquid discharge parameters through optimized voltage parameter combinations.
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 approach enhances the stability and efficiency of liquid discharge by effectively removing air bubbles, reducing liquid stagnation, and minimizing liquid consumption, while maintaining discharge quality.
Implementation Method 1
an actuator on the pressure chamber, the actuator deforming the nozzle plate to discharge the liquid in the pressure chamber from the nozzle, wherein a drive voltage is applied to the actuator
Data Source
AI summary
A liquid discharge head includes a pressure chamber; a nozzle to discharge a liquid from the pressure chamber; a nozzle plate on the pressure chamber; and an actuator on the nozzle plate, the actuator deforming the nozzle plate to discharge the liquid in the pressure chamber from the nozzle, wherein a drive voltage is applied to the actuator to generate a controlled flow of the liquid in the pressure chamber.