Dual-Channel Ink Circulation for Bubble Removal
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Solution Overview
Problem
Liquid ejection apparatuses, such as ink jet printers, face challenges in reliably discharging air bubbles from complex liquid channels, leading to inefficient purging operations and potential nozzle clogging, as existing methods either waste liquid or fail to effectively remove bubbles due to pressure limitations.
Innovation Solution
A liquid ejection apparatus with a mode switching unit that allows for selective operation between liquid ejection and circulation modes, using independent liquid channels to minimize liquid usage and efficiently remove air bubbles, along with a nozzle cleaning mode to address clogging, utilizing a piezoelectric actuator and partitioned pressure chambers to enhance bubble removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid is circulated under high pressure to discharge air bubbles, then air bubbles can be reliably discharged, but nozzle menisci are broken and liquid leaks from nozzles
Solution Approach 1:
The system dynamically switches between circulation mode (for bubble discharge) and ejection mode (for normal operation) based on operational requirements. The mode switching unit changes the system state to prevent nozzle damage during high-pressure circulation while enabling effective bubble removal.
Solution Approach 2:
The liquid circulation path is segmented into two independent channels: a first liquid channel for circulation mode and a second liquid channel for ejection mode. This segmentation allows the circulation path to be separated from the nozzle ejection path, enabling high-pressure circulation without damaging nozzle menisci.
2Object-generated harmful factors
If liquid is circulated under low pressure to avoid nozzle damage, then nozzle integrity is maintained, but air bubbles cannot be reliably discharged
Solution Approach 1:
The system uses dynamic mode switching to achieve low-pressure circulation during normal operation and high-pressure circulation during maintenance mode. The mode switching unit enables the system to adapt pressure levels based on whether bubble discharge is required, maintaining nozzle integrity while enabling effective purging when needed.
3Reliability
If multiple purging operations are performed to discharge air bubbles from complex liquid channels, then air bubbles are discharged, but liquid is wasted
Solution Approach 1:
The liquid circulation system is divided into two independent channels: the first liquid channel forms a closed circulation loop between the liquid supply source and pressure chambers for efficient bubble discharge, while the second liquid channel handles ejection operations. This segmentation allows purging to be performed without involving the nozzle ejection path, reducing liquid waste.
Solution Approach 2:
The first liquid channel provides continuous circulation between the liquid supply source and pressure chambers, enabling sustained bubble discharge operations. The independent circulation path ensures that purging operations can be performed continuously and efficiently without interruption or repeated cycles that would waste liquid.
4Device complexity
If a single liquid channel is used for both circulation and ejection, then device complexity is reduced, but bubble discharge and ejection operations interfere with each other
Solution Approach 1:
The liquid channel system is segmented into two independent channels: the first liquid channel dedicated to circulation operations and the second liquid channel dedicated to ejection operations. This segmentation eliminates interference between bubble discharge and ejection operations, ensuring reliable performance of both functions despite increased structural complexity.
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
Enables reliable discharge of air bubbles with reduced liquid usage and improved nozzle cleaning, preventing clogging and maintaining efficient operation of the ejection apparatus.
Implementation Method 1
an actuator which applies pressure selectively to liquid in the pressure chambers to eject the liquid through the nozzles
Data Source
AI summary
An ink jet printer as an liquid ejection apparatus includes two ink channels which are independent from each other and communicate an ink tank and a pressure chamber communicating with a nozzle, a pump pressurizing ink in one of the ink channels, and a mode switching section capable of switching between two modes of ink ejection mode and ink circulation mode. In the ink ejection mode, ink is provided from the ink tank to the pressure chamber to the pressure chamber through the two ink channels, so that the ink is ejected through the nozzle. In the ink circulation mode, the pump pressurizes ink in one of the ink channels, so that the ink is forcibly circulated between the ink tank and the pressure chamber. The liquid ejection apparatus is capable of reliably discharging air bubbles remaining in the ink by ejecting a minimum amount of liquid through the nozzle.