Hybrid PTC NTC Resistance Heating Element for Fusing
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Solution Overview
Problem
Resistance heating elements in electrophotographic image forming apparatuses experience significant resistance changes during initial warm-up, leading to overheating and reduced durability, which affects energy efficiency and performance.
Innovation Solution
A hybrid resistance heating element is developed, combining a positive temperature coefficient (PTC) resistance heating layer and a negative temperature coefficient (NTC) resistance heating layer with specific electroconductive fillers and base polymers, optimized to maintain a controlled resistance changing ratio within ±40% to ±10% across temperature ranges, using a stacked or island structure with electrode connections to manage current flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional resistance heating element is used, then heating function is provided, but resistance changes significantly during warm-up causing overheating and reduced durability
Solution Approach 1:
The patent applies composite materials by combining PTC (positive temperature coefficient) and NTC (negative temperature coefficient) resistance heating layers into a single hybrid structure. The PTC layer increases resistance with temperature while the NTC layer decreases resistance with temperature, creating a balanced composite that stabilizes overall resistance changes during warm-up operation, thereby improving durability and reliability
2Use of energy by moving object
If resistance heating element operates with significant resistance change, then heating capability is maintained, but power consumption increases and energy efficiency decreases
Solution Approach 1:
The patent utilizes parameter changes by exploiting the temperature-dependent resistance characteristics of both PTC and NTC materials. During warm-up, the NTC layer's decreasing resistance compensates for the PTC layer's increasing resistance, maintaining more stable power consumption and improving energy efficiency throughout the heating process
3Manufacturing precision
If single-layer PTC or NTC heating element is used, then structure is simple, but resistance control precision is insufficient
Solution Approach 1:
The patent applies segmentation by dividing the heating element into distinct PTC and NTC layers, each with specific resistance characteristics. This segmented structure allows independent optimization of each layer's properties while achieving superior overall resistance control precision that would be impossible with a single-layer design
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 hybrid resistance heating element achieves quick heating, improved durability, and reduced power consumption by stabilizing resistance changes, preventing overheating and extending the lifespan of the heating element while maintaining efficient heat transfer for fusing operations.
Implementation Method 1
a positive temperature coefficient ('PTC') resistance heating layer having a positive temperature coefficient
Implementation Method 2
a negative temperature coefficient ('NTC') resistance heating layer which is electrically connected to the PTC resistance heating layer and has a negative temperature coefficient
Implementation Method 3
resistance heating element... generates heat using electricity
Data Source
AI summary
A resistance heating element includes a positive temperature coefficient resistance heating layer having a positive temperature coefficient, and a negative temperature coefficient resistance heating layer, which is connected to the positive temperature coefficient resistance heating layer and has a negative temperature coefficient.