Piezoelectric Actuator Heater Placement for Ink Viscosity Control
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Solution Overview
Problem
Existing ink-jet technologies face challenges in maintaining optimal ink viscosity at low temperatures, requiring increased drive voltage and costly high-voltage components, and struggle to efficiently heat the ink while operating the piezoelectric actuator without interfering with the heater's functionality.
Innovation Solution
A liquid transporting apparatus with a piezoelectric actuator and a separate heater system, where the heater is placed on the vibration plate not covered by the piezoelectric body, allowing independent control and efficient heating of the ink, even when the actuator is in operation, using a heating element and electrodes that do not interfere with the actuator's electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive voltage of the piezoelectric actuator is increased to jet ink droplets at low temperature, then the inkjetting performance is improved, but the cost increases due to requiring high-voltage components
Solution Approach 1:
The patent changes the physical state of the ink by heating it to reduce viscosity, allowing the piezoelectric actuator to operate at normal voltage levels. This parameter change (temperature) resolves the contradiction by enabling reliable inkjetting without requiring expensive high-voltage components.
Solution Approach 2:
The patent introduces a heater as an intermediary device that mediates between the low-temperature environment and the inkjetting process. The heater warms the ink to an optimal temperature range, allowing the piezoelectric actuator to function properly without needing high voltage, thus resolving the cost-performance contradiction.
2Reliability
If the heater is formed on the common electrode to prevent dew formation, then the reliability is improved, but the heater cannot operate simultaneously with the piezoelectric actuator
Solution Approach 1:
The patent segments the electrode structure by providing separate electrodes for the heater and the piezoelectric actuator. This segmentation allows independent control and simultaneous operation of both the heater and the actuator, resolving the contradiction between dew prevention reliability and operational flexibility.
Solution Approach 2:
The patent creates a multi-functional electrode system where separate electrodes serve dual purposes: the heater electrode provides both dew prevention and ink heating functions, while the piezoelectric electrodes maintain their jetting function. This universality enables both functions to operate simultaneously without interference.
3Use of energy by moving object
If the heater is provided on the vibration plate, then the heating efficiency is improved, but the heater interferes with the piezoelectric actuator operation
Solution Approach 1:
The patent applies local quality by providing the heater only in the uncovered area of the vibration plate, specifically in regions where the piezoelectric body does not extend. This localized heating approach maintains high heating efficiency for the ink while avoiding interference with the piezoelectric actuator's electric field and mechanical operation.
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 solution improves the operational timing and heating efficiency of the ink, maintaining consistent viscosity and enabling stable inkjetting by directly transferring heat to the ink through the vibration plate, reducing the need for high-voltage components and enhancing manufacturing efficiency.
Implementation Method 1
an electric field acts in a portion (active portion) of the piezoelectric layer sandwiched between the individual electrode and the common electrode, and there occurs a deformation in a direction of thickness of the piezoelectric layer. Moreover, this deformation of the piezoelectric layer is propagated to the vibration plate, and a volume of a pressure chamber corresponding to the individual electrode is changed.
Implementation Method 2
a heater is provided in the uncovered area, the heater generating heat by being applied with an electric current
Implementation Method 3
heat of the heater is propagated to the vibration plate without being drawn by the piezoelectric body. Consequently, the heat of the heater is directly propagated to the liquid inside the channel efficiently via the vibration plate
Data Source
AI summary
A liquid transporting apparatus includes a channel unit in which a plurality of pressure chambers are provided, and a piezoelectric actuator which changes individually a volume of each of the pressure chambers. The piezoelectric actuator includes a vibration plate, a piezoelectric body provided on one surface of the vibration plate, and electrodes which apply an electric voltage to the piezoelectric body. The other surface of the vibration plate is joined to the channel unit to close openings of the pressure chambers, and the one surface of the vibration plate includes an uncovered area which is not covered with the piezoelectric body. Since a heater is provided in the uncovered area, and an electrode for applying an electric current is provided separately from the electrodes of the piezoelectric actuator, it is possible to operate the heater even when the piezoelectric actuator is being driven.