Impedance-Based Ink Level Sensor for CIJ Printers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Continuous ink jet (CIJ) printers face challenges in measuring ink levels in tanks independently of ink conductivity, requiring complex and costly sensors that are not easily implementable for reliable and continuous operation.
Innovation Solution
A device and method using impedance-measuring electrodes to calculate ink levels in tanks, with two pairs of electrodes measuring different heights, allowing for continuous and linear measurement independent of ink conductivity, and incorporating means to correct for tank wall and electrode configuration effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensors are used to measure ink levels, then measurement can be performed, but the measurement depends on ink conductivity requiring complex and costly sensors
Solution Approach 1:
The measurement system is segmented into multiple electrode pairs, each pair measuring impedance at different height levels. This segmentation allows the system to measure ink level by comparing impedance values across different segments, eliminating dependence on bulk ink conductivity and enabling accurate measurement with simpler components.
Solution Approach 2:
The patent replaces complex conductivity-based sensing mechanisms with a simpler impedance measurement system using multiple electrode pairs. By measuring impedance at different heights and comparing values, the system substitutes a straightforward electrical measurement approach for the previously required complex conductivity-dependent sensors.
2Measurement precision
If conductivity-dependent sensors are used, then ink level can be measured, but the system becomes costly and less reliable for continuous operation
Solution Approach 1:
By dividing the measurement system into multiple electrode pairs at different heights, the patent creates a measurement approach that is independent of bulk ink conductivity changes. This segmentation ensures reliable continuous operation as each electrode pair measures local impedance, and the combined measurements provide accurate level indication regardless of conductivity variations during continuous printing operations.
3Device complexity
If simple impedance measurement is used, then device complexity is reduced, but measurement independence from ink conductivity is not achieved
Solution Approach 1:
The patent transitions from a single-point impedance measurement to a multi-dimensional measurement approach by placing electrode pairs at different vertical heights. This dimensional expansion allows the system to measure ink level by comparing impedance values across the height dimension, achieving independence from bulk ink conductivity while maintaining simple impedance measurement techniques.
Solution Approach 2:
The system uses feedback from multiple electrode pairs measuring impedance at different heights. By comparing the impedance values from these multiple measurement points, the system determines ink level independently of conductivity variations. The feedback mechanism compares relative impedance values to identify the meniscus position, achieving conductivity independence through comparative analysis.
4Ease of manufacture
If discrete level sensors are used, then simple measurement points are obtained, but continuous level measurement is not achieved
Solution Approach 1:
The patent segments the measurement range into multiple zones using electrode pairs at different heights. Each electrode pair provides measurement data for a specific height segment, and by combining these segmented measurements, the system achieves continuous level measurement capability while maintaining the simplicity of discrete impedance measurement points.
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, continuous, and cost-effective ink level measurement in CIJ printers, independent of ink conductivity, simplifying the measurement process and reducing component complexity while maintaining high accuracy.
Implementation Method 1
first means for measuring the impedance of a first predetermined liquid height, in said tank; second means for measuring the impedance of any second height of the same liquid in said tank
Data Source
AI summary
A device for continuously measuring a level of an ink in a tank (10) of a continuous ink-jet (CIJ) printer, including: a first pair of electrodes (24, 26) and part for connecting this pair of electrodes in series, for measuring the impedance of a first predetermined height of the ink, in the tank, a second pair of electrodes (16, 18) and part for connecting this second pair of electrodes in series, for measuring a second height of the ink in the tank, this second height being included between this first height and a maximum level; part for calculating the second height, from the resistive components of the 2 impedances measured, independently of the ink conductivity.