Piezoelectric Liquid Ejecting Head Diaphragm Pressure Control
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Solution Overview
Problem
The efficiency of liquid ejecting heads, such as ink jet type recording heads, is limited by the poor energy transfer efficiency from piezoelectric elements due to a significant initial bent state of the diaphragm, which results in inadequate displacement of liquid droplets.
Innovation Solution
A liquid ejecting head design that adjusts the initial bent state of the diaphragm by creating a sealed space with controlled pressure conditions, either positive or negative, to optimize the displacement amount while reducing the reached bent amount, thereby enhancing the energy efficiency of the piezoelectric element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the initial bent amount of the diaphragm is increased, then the reached bent amount is increased, but the displacement amount does not significantly increase
Solution Approach 1:
The patent applies parameter changes by adjusting the initial bent amount of the diaphragm to an optimal range (0.5μm to 5μm) rather than allowing it to increase indefinitely. This optimization ensures that the diaphragm achieves sufficient displacement for liquid ejection while minimizing energy consumption, resolving the contradiction between reaching a bent state and energy efficiency.
2Shape
If the initial bent amount of the diaphragm is increased, then the reached bent amount is increased, but the displacement amount does not significantly increase
Solution Approach 1:
The patent optimizes the initial bent amount parameter to a specific range (0.5μm to 5μm) to achieve the best balance between the reached bent amount and displacement amount. This parameter optimization ensures that the diaphragm maintains adequate displacement capability for liquid ejection while avoiding excessive bending that would waste energy.
3Shape
If the diaphragm is bent toward the piezoelectric element side initially, then the reached bent amount is increased, but the energy efficiency is reduced
Solution Approach 1:
The patent controls the initial bent amount within a specific range (0.5μm to 5μm) to minimize energy loss while maintaining necessary reached bent amount. This parameter control ensures that the diaphragm does not waste excessive energy on initial bending, thereby reducing energy loss while still achieving adequate displacement for liquid ejection.
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 achieves highly-efficient liquid discharging properties by ensuring adequate displacement with reduced energy consumption, improving the overall performance of the liquid ejecting head.
Implementation Method 1
a piezoelectric element on one surface side of a flow-path forming substrate in which a pressure generation chamber communicating with nozzle openings is provided. In the ink jet type recording head, a diaphragm is deformed by driving the piezoelectric element, and thus a pressure in the pressure generation chamber is changed.
Implementation Method 2
a joining substrate that is joined to the flow-path forming substrate and forms a sealed space for sealing the actuator device, in which a pressure in the sealed space is adjusted such that the diaphragm is drawn up to the actuator side or is pressed down to the pressure generation chamber side
Data Source
AI summary
A liquid ejecting head includes a flow-path forming substrate including pressure generation chambers that communicate with nozzle openings through which ink is ejected, a piezoelectric element that applies a pressure to the pressure generation chambers via a diaphragm, and a protection substrate that forms a sealed space for sealing the piezoelectric element, in which a pressure in the sealed space is adjusted such that the diaphragm is drawn up to the piezoelectric element side and an initial bent position of the diaphragm is adjusted.