Fusible Link Resistor Circuit for Thermal Inkjet Failure Isolation
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Solution Overview
Problem
In thermal inkjet printing devices, failed resistive heating elements can cause arcing and shorting, leading to cascading failures of adjacent elements and significant damage, with existing electrical clamps occupying large space and not disabling failed resistors, thus not effectively preventing propagation of failure.
Innovation Solution
A system with a fusible link disposed between a field effect transistor (FET) and the resistive heating element, which fuses open upon failure to electronically isolate the resistor, reducing the need for clamps and preventing failure propagation, and a controller to execute nozzle replacement techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical clamps are used to prevent failure propagation, then reliability is improved, but device complexity and area increase
Solution Approach 1:
The patent extracts the failure isolation function from complex electrical clamps and implements it through a simple fusible link that melts to disconnect the circuit. This removes unnecessary circuit complexity while maintaining reliability by preventing failure propagation through a minimalist approach.
Solution Approach 2:
The fusible link is designed as a disposable, single-use component that sacrifices itself (melts and breaks) to protect the rest of the circuit. This simple, low-cost element provides reliable failure isolation without requiring complex reusable mechanisms like electrical clamps.
2Reliability
If electrical clamps are used to isolate failed resistors, then reliability is improved, but area occupied increases
Solution Approach 1:
The patent extracts the isolation function from bulky electrical clamps and implements it through a minimal fusible link that occupies minimal space. This maintains reliable failure isolation while dramatically reducing the area required in the printhead.
Solution Approach 2:
The fusible link serves as a compact, disposable isolation element that provides reliable failure containment in a minimal footprint, eliminating the need for large electrical clamps and freeing up printhead area for other functions.
3Device complexity
If simple fusible link is used instead of electrical clamps, then device complexity is reduced, but effectiveness in disabling failed resistors may be compromised
Solution Approach 1:
The patent converts the harmful effect of resistor failure (continued current flow causing damage) into a beneficial isolation mechanism. The fusible link exploits the very current that causes failure to melt and break the circuit, thereby automatically disabling the failed resistor and protecting the rest of the system.
Solution Approach 2:
The fusible link provides automatic failure isolation without requiring external control or complex mechanisms. When the resistor fails, the excessive current automatically melts the fusible link, which self-service isolates the failed component from the rest of the circuit.
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 reduces the size and complexity of the printhead, prevents cascading failures, and simplifies the electrical circuitry, while enabling efficient isolation of failed resistors without the need for clamps, thus enhancing the reliability and manufacturing efficiency of the printing device.
Implementation Method 1
a fusible link disposed between a field effect transistor (FET) and the resistive heating element, which fuses open upon failure
Implementation Method 2
The jettable fluid may be ejected from the ejection chamber by, for example, heating a resistive element
Data Source
AI summary
A system for isolating a failed resistor in a liquid dispensing system including a fusible links described. The system includes drive circuitry to drive a voltage supply to a resistor. The fusible link is disposed between a field effect transistor (FET) and the resistor. The fusible link is to fuse apart upon failure of the resistor.