Liquid Ejection Head Conductivity Feedback for Kogation Removal
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Solution Overview
Problem
Existing liquid ejection head cleaning methods fail to consistently manage the elution amount of the material layer due to variations in ink conductivity, leading to inadequate kogation removal and premature wear of the head.
Innovation Solution
A liquid ejection head with a conductivity measuring unit that sets cleaning conditions based on measured ink conductivity, ensuring a constant elution amount of the upper electrode through electrochemical reactions, thereby effectively removing kogation and maintaining print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper protective layer is made of a material elutable by electrochemical reaction to remove kogation, then kogation removal capability is improved, but the elution amount varies with ink conductivity leading to inconsistent cleaning效果
Solution Approach 1:
The patent introduces a conductivity measuring unit that measures ink conductivity before cleaning operations. Based on the measured conductivity value, the cleaning control unit adjusts the cleaning conditions (voltage, time) to maintain a constant elution amount of the upper electrode material. This feedback mechanism ensures consistent kogation removal effectiveness despite variations in ink composition.
Solution Approach 2:
The patent changes the cleaning parameters (voltage, time) based on the measured conductivity of the ink. By adjusting these parameters dynamically according to the conductivity measurement, the system maintains optimal cleaning conditions and ensures consistent elution amount of the upper electrode material throughout the cleaning process.
2Device complexity
If fixed cleaning conditions are used without conductivity measurement, then device complexity is reduced, but cleaning effectiveness deteriorates due to ink conductivity variations
Solution Approach 1:
The conductivity measuring unit provides feedback on ink conductivity to the cleaning control unit. This feedback enables the system to automatically adjust cleaning conditions to maintain optimal effectiveness, preventing degradation of printing quality due to inconsistent cleaning.
Solution Approach 2:
The system performs conductivity measurement before the cleaning operation to determine the appropriate cleaning conditions in advance. This preliminary measurement allows the cleaning process to be optimized for the specific ink properties, ensuring effective kogation removal from the start.
3Productivity
If the upper electrode material is highly elutable to remove kogation efficiently, then cleaning speed is improved, but the material layer wears out prematurely
Solution Approach 1:
By measuring conductivity and using this feedback to control cleaning parameters, the system prevents excessive elution of the upper electrode material. The feedback mechanism ensures that only the necessary amount of material is removed for effective cleaning, preserving the electrode's service life.
Solution Approach 2:
The cleaning parameters (voltage, time) are dynamically adjusted based on conductivity measurements to achieve the minimum necessary elution for effective cleaning. This parameter optimization prevents premature wear while maintaining efficient cleaning speed.
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 ensures reliable kogation removal and stable ejection characteristics, extending the life of the liquid ejection head and maintaining high-quality printing by accurately managing the elution amount of the material layer.
Implementation Method 1
an upper electrode configured to cover at least a portion heated by the electrothermal converting portion of the protective layer, and made of a material eluted by an electrochemical reaction with the liquid
Implementation Method 2
an electrothermal converting portion disposed in the liquid chamber... generated by electrothermal converting elements enables high quality and high speed printing
Implementation Method 3
a conductivity measuring unit of the liquid provided with an electrode pair that touches the liquid in the liquid chamber
Data Source
AI summary
Cleaning under appropriate cleaning conditions is performed by disposing an electrode pair for measuring conductivity in the same liquid chamber as that of a material layer (i.e., an upper electrode) of a surface of a thermal action portion to be eluted, and measuring conductivity of a liquid using the electrode pair before kogation is removed.