Fixing Device Lead Wire Routing for Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In image forming apparatuses, the electromagnetic noise caused by leaked magnetic flux affects the wiring of electric components like thermistors and thermostats located inside the fixing belt, leading to increased electromagnetic noise due to the large loops of lead wires surrounding the belt unit.
Innovation Solution
A fixing device with a belt guide and an excessive temperature rise preventing device, where lead wires are routed to minimize loop formation and electromagnetic noise interference, using an electro conductive magnetic shielding member to cover the curved portions of the lead wires and maintain the heating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electric components are located inside the fixing belt to achieve compact design and improve heat transfer efficiency, then the device structure is simplified and heating performance is improved, but electromagnetic noise affects the wiring of electric components due to leaked magnetic flux
Solution Approach 1:
The patent extracts the problematic loop configuration of lead wires and replaces it with a flat wiring arrangement that extends in the axial direction of the fixing belt. This extraction of the harmful geometric feature (large loop area) while preserving the functional requirement (electrical connection) resolves the electromagnetic noise issue without adding complex shielding structures.
Solution Approach 2:
The patent applies different wiring configurations to different regions: lead wires connecting electric components inside the fixing belt are made to extend in the axial direction with minimal loop formation, while the belt guide maintains its structural integrity. This localized optimization of wire routing in the region most affected by magnetic flux resolves the contradiction between compact design and electromagnetic noise reduction.
2Reliability
If lead wires are routed in conventional configurations to ensure electrical connection, then electrical functionality is maintained, but large loop areas form that increase electromagnetic noise susceptibility
Solution Approach 1:
The patent changes the geometric parameters of lead wire routing by extending wires in the axial direction of the fixing belt rather than allowing them to form radial loops. This parameter change (wire routing geometry) maintains electrical connectivity while reducing the loop area exposed to leaked magnetic flux, thereby reducing electromagnetic noise susceptibility.
3Loss of time
If the fixing belt is made thin to reduce heat capacity and shorten warm-up time, then heating efficiency is improved, but magnetic flux penetration and electromagnetic noise increase
Solution Approach 1:
The patent converts the harmful effect of magnetic flux penetration through the thin fixing belt into a beneficial arrangement by orienting lead wires in the axial direction. The wire routing is specifically designed to minimize loop area in the region where magnetic flux penetration is most significant, thereby converting the potential harm of flux penetration into an opportunity for optimized wire placement that reduces electromagnetic noise.
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
Reduces the effect of electromagnetic noise on electric components by minimizing loop areas and using a magnetic shielding member to restrain leaked magnetic flux, ensuring effective temperature sensing and preventing excessive temperature rises.
Implementation Method 1
a heat source in an induction heating (IH) manner is applied. The heat source in the IH manner makes magnetic flux generated by a coil act on a heating member, such as a fixing belt, to heat the heating member
Implementation Method 2
Almost 80% of the magnetic flux generated by the coil is absorbed by a belt base material of the fixing belt and converted to eddy current and almost remained magnetic flux penetrates the fixing belt and is absorbed by the belt guide and converted to eddy current
Data Source
AI summary
A fixing device includes a fixing belt, a belt guide, a pressuring member, a heat source and an excessive temperature rise preventing device. The guide contacts with the inside of the belt to assist the belt's rotation track. The heat source is located across the belt to the pressuring member to induction-heat the belt. The preventing device has first and second lead wires connected at one and another end sides in an axial direction of the belt and prevents excessive temperature rise of the guide in noncontact. The first lead wire is extended to one end side and pulled out from the inside to the outside via one end side in the belt. The second lead wire is extended to another end side, curved toward one end side, extended to one end side and pulled out from the inside to the outside via one end side in the belt.