Thermal Bend Actuator for Inkjet Nozzles
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Solution Overview
Problem
Existing thermal bend actuated inkjet nozzles face inefficiencies in bend actuation and drop ejection characteristics, particularly in achieving high packing density and optimal droplet ejection with minimal energy input.
Innovation Solution
The design incorporates a thermal bend actuator with a reduced working face area, optimized for peak actuator velocity, and a hydrophobic layer to control ink pressure, allowing for efficient ink ejection and varying droplet volumes by adjusting hydrostatic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the working face area of the thermal bend actuator is reduced, then drop ejection efficiency is improved and satellite droplets are reduced, but the actuator generates less positive pressure pulse in the ink
Solution Approach 1:
The patent optimizes the working face area to a specific range (less than 800 square microns, preferably 200-600 square microns) to achieve peak actuator velocity. This parameter optimization resolves the contradiction by finding the sweet spot where the actuator generates sufficient pressure pulse while maintaining high ejection efficiency and minimizing satellite droplets.
Solution Approach 2:
The patent focuses on achieving peak actuator velocity through optimized working face area, emphasizing the dynamic aspect of the actuation process. The velocity-optimized design ensures that the actuator moves rapidly enough to eject droplets efficiently while generating adequate pressure pulse during the brief actuation window.
2Speed
If the working face area is optimized for peak velocity, then ejection efficiency improves, but the area is constrained to less than 800 square microns
Solution Approach 1:
The patent establishes a specific parameter range for the working face area (less than 800 square microns, preferably 200-600 square microns) that optimizes peak actuator velocity. This parameter constraint resolves the contradiction by defining the optimal size range that achieves both high velocity and efficient ejection.
3Quantity of substance
If hydrostatic pressure is increased to increase droplet volume, then droplet volume increases, but energy input requirements increase
Solution Approach 1:
The patent utilizes hydrostatic pressure (a hydraulic principle) to control droplet volume. By adjusting the hydrostatic pressure in the ink supply system, the patent enables variable droplet volumes without requiring additional energy input for each droplet, as the pressure provides the driving force passively.
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 configuration enhances drop ejection efficiency, reduces satellite droplets, and enables denser nozzle packing while achieving consistent and adjustable droplet volumes, improving overall print quality and versatility in inkjet printing applications.
Implementation Method 1
when a current is passed through the active beam, the active beam heats and expands relative to the passive beam
Implementation Method 2
the active beam heats and expands relative to the passive beam resulting in bending of the actuator
Implementation Method 3
a hydrophobic layer to control ink pressure, allowing for efficient ink ejection and varying droplet volumes by adjusting hydrostatic pressure
Data Source
AI summary
An inkjet printer including: a printhead having a plurality of nozzles assemblies, each nozzle assembly having: a nozzle chamber for containing ink, the chamber having a nozzle opening and an ink inlet; and a bend actuator for ejecting ink droplets from the nozzle opening by generating a positive pressure pulse in the ink during bending of the actuator. An ink supply system supplies ink to the printhead so that a hydrostatic pressure of ink can be varied. Increasing the hydrostatic ink pressure increases a volume of the ejected ink droplets, and decreasing the hydrostatic ink pressure decreases a volume of the ejected ink droplets.