Lead-Free Thermistor Heater for Image Forming
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Solution Overview
Problem
Existing heaters used in image forming apparatuses, such as copying machines, contain lead in their thermistors, posing environmental concerns and requiring design considerations to mitigate these issues.
Innovation Solution
A heater design that replaces lead-containing thermistors with manganese, cobalt, and optionally copper or nickel, ensuring the thermistor's mass content prioritizes these elements, with ruthenium within specific ranges to maintain accurate temperature detection and environmental sustainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lead-containing thermistors are used in heaters, then temperature detection accuracy is maintained, but environmental harm increases due to lead pollution
Solution Approach 1:
The patent changes the material composition parameters of the thermistor by replacing lead with specific combinations of manganese, cobalt, copper, and nickel in defined proportions. This substitution maintains the thermistor's temperature detection functionality while eliminating the harmful lead component, directly resolving the contradiction between measurement precision and environmental harm.
Solution Approach 2:
The patent employs composite material design by creating a multi-element oxide system (manganese, cobalt, copper, and nickel oxides) to replace the traditional lead-based thermistor material. This composite approach ensures that the alternative material achieves comparable electrical and thermal properties necessary for accurate temperature detection without the environmental drawbacks of lead.
2Object-affected harmful factors
If lead is replaced in thermistors, then environmental sustainability improves, but temperature detection performance may deteriorate
Solution Approach 1:
The patent carefully adjusts the compositional parameters of the lead-free thermistor, specifying precise ranges for manganese oxide (40-70 wt%), cobalt oxide (10-30 wt%), copper oxide (5-20 wt%), and nickel oxide (5-20 wt%). These parameter optimizations ensure that the alternative material achieves electrical resistance and temperature coefficient values suitable for accurate temperature detection, preventing performance deterioration.
Solution Approach 2:
The patent applies local quality by optimizing specific regions of the thermistor's material composition and structure. By controlling the distribution and concentration of different metal oxides within the thermistor body, the invention ensures that local electrical and thermal properties are tailored to maintain detection performance while using environmentally friendly materials.
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 solution allows for accurate temperature detection and control in heaters, reducing environmental impact by eliminating lead while maintaining effective thermistor performance within specified sheet resistance and B constant ranges, ensuring reliable operation and adherence to environmental standards.
Implementation Method 1
The heater generates heat from a resistance heating element formed on one surface of a substrate by power supplied from an electrode for power supply
Implementation Method 2
a thermistor is disposed on the other surface of the substrate. The heater is adjusted to an appropriate temperature while the supply of power is controlled on the basis of a temperature detected by the thermistor
Data Source
AI summary
A heater of an embodiment includes a substrate, a resistance heating element, and a thermistor. The substrate includes a first surface and a second surface located on the side opposite to the first surface. The resistance heating element is disposed on the first surface. The thermistor is disposed on the second surface and does not contain lead.