Inkjet Nozzle Issue Detection via Impedance Monitoring
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Solution Overview
Problem
Inkjet printers face issues such as nozzle blockages, stray bubbles, and weak drive bubble formations, which affect the accuracy and reliability of ink droplet release, leading to inconsistent impedance measurements and potential image quality problems.
Innovation Solution
A method involving an impedance sensor and a drive bubble formation mechanism within the ink chamber to measure impedance changes and determine issues like blockages or stray bubbles, allowing for real-time diagnosis and remedial actions, such as adjusting heater energy or compensating with other nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impedance measurements are used to monitor nozzle health, then nozzle issues can be detected, but measurement precision deteriorates due to inconsistent readings from blockages and stray bubbles
Solution Approach 1:
The patent applies preliminary action by measuring impedance at multiple predetermined time points after drive bubble formation (first time point before bubble collapse, second time point after collapse). This allows differentiation between normal impedance variations and actual nozzle pathologies, improving measurement precision while maintaining reliability in detecting blockages and stray bubbles.
2Reliability
If real-time impedance monitoring is implemented, then nozzle issues can be detected during operation, but device complexity increases due to additional sensors and measurement mechanisms
Solution Approach 1:
The patent applies universality by integrating the impedance sensor with existing drive bubble formation mechanisms and ink chamber structures. The same drive bubble formation process serves both its primary function of ejecting ink droplets and the secondary function of enabling impedance measurements for nozzle health monitoring, thereby reducing additional device complexity while maintaining printing process reliability.
3Measurement precision
If multiple impedance measurements are taken at different time points, then measurement precision improves for detecting nozzle issues, but loss of time increases due to additional measurement steps
Solution Approach 1:
The patent applies continuity of useful action by taking impedance measurements at multiple time points during the continuous drive bubble formation and collapse cycle. The measurements are integrated into the normal printing operation timeline, allowing precise detection of nozzle issues (blockages, stray bubbles) without significant time loss, as the measurements occur during the natural operational cycle rather than requiring separate diagnostic procedures.
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 accurate detection of nozzle issues in real-time, ensuring consistent ink droplet release and maintaining image quality by identifying and addressing problems like blockages and stray bubbles, thereby improving the overall printing process.
Implementation Method 1
Some print heads use a resistive heater positioned within the chamber to evaporate a small amount of at least one component of the liquid ink. In many cases, a major component of the liquid ink is water, and the resistive heater evaporates the water.
Implementation Method 2
Some print heads use a resistive heater positioned within the chamber to evaporate a small amount of at least one component of the liquid ink.
Implementation Method 3
An embedded conductor trace that intersects a nozzle can be used to measure the impedance across the nozzle gap. The nozzle health is monitored during nozzle operation through measuring changes in impedance across the nozzle as fluid passes through the nozzle.
Data Source
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AI summary
Determining an issue in an inkjet nozzle may include activating (801) a drive bubble formation mechanism in an ink chamber to eject an ink droplet through the inkjet nozzle and measuring (802) the drive bubble in the ink chamber after the drive bubble formation mechanism is activated.