Fixing Device Resistor Layers Current Distribution
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Solution Overview
Problem
Conventional fixing devices with resistance heating belts experience localized overheating and reduced longevity due to uneven current distribution, leading to potential smoke formation and accelerated deterioration of the resistance heating layer.
Innovation Solution
Incorporating resistor layers with higher volume resistivity than the electrodes between the resistance heating layer and the electrodes, ensuring even current distribution and preventing localized overheating by adjusting electric current density across the heating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electrodes with small volume resistivity are used to supply current to the resistance heating layer, then the electrodes can efficiently conduct electricity, but electric current becomes localized at specific portions (axially inner edges) causing uneven current distribution
Solution Approach 1:
A resistor layer is introduced as an intermediary component between the electrode and the resistance heating layer. This resistor layer has a volume resistivity that is higher than the electrode but lower than the resistance heating layer, serving as a current distribution mediator that spreads the localized current from the electrode across a wider area of the resistance heating layer, preventing current concentration at axially inner edges
Solution Approach 2:
The volume resistivity parameter is strategically varied across different layers: the electrode has the lowest volume resistivity for efficient current conduction, the resistor layer has an intermediate volume resistivity to distribute current evenly, and the resistance heating layer has the highest volume resistivity for heat generation. This gradient in volume resistivity parameters optimizes both current distribution and heating efficiency
2Power
If current is localized at axially inner edges of the resistance heating layer, then the edges generate excessive heat, but this causes local overheating, smoke formation, and accelerated deterioration
Solution Approach 1:
The resistor layer acts as a current-distributing intermediary that prevents current concentration at the axially inner edges of the resistance heating layer. By having intermediate resistivity between the electrode and the heating layer, it spreads the current flow across the entire width of the heating layer, ensuring uniform heat generation and preventing localized overheating that would cause smoke and deterioration
Solution Approach 2:
The resistor layer is positioned specifically at the interface between the electrode and the resistance heating layer, where current distribution is most critical. This localized structure addresses the specific problem of edge current concentration without modifying the overall heating belt design, providing uniform current distribution precisely where needed
3Speed
If the resistance heating layer has high temperature rise characteristics with small heat capacity, then warm-up time is shortened and power consumption is reduced, but the system becomes more sensitive to current distribution uniformity
Solution Approach 1:
The resistor layer serves as a current distribution intermediary that ensures uniform current flow across the resistance heating layer. This is particularly important for materials with small heat capacity that rapidly respond to current input - the resistor layer prevents localized current spikes that would cause uneven temperature distribution, ensuring the entire heating surface reaches the target temperature uniformly and efficiently
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 configuration stabilizes the resistance heating layer's temperature, preventing overheating and degradation, thereby extending the lifespan of the heat-generating belt and ensuring consistent performance.
Implementation Method 1
the resistance heating layer generates Joule heat upon application of alternating current
Data Source
AI summary
A fixing device includes: a rotating fixing body including a resistance heating layer disposed throughout an entire periphery; and a pressure-applying member pressed against an outer peripheral surface of the rotating fixing body to form a fixing nip. The rotating fixing body further includes: a pair of electrodes each of which is a layer disposed along a different one of edges of the resistance heating layer throughout an entire periphery; and a pair of resistor layers each of which is disposed between the resistance heating layer and a different one of the electrodes. An inner edge of each resistor layer is positioned at a location corresponding to or axially more inwardly of an inner edge of the electrode. The resistor layers are higher in volume resistivity than the electrodes.