Heater with Edge Temperature Detection for Uniform Heating
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Solution Overview
Problem
In image heating devices used in electrophotographic systems, the temperature distribution across heating blocks can become uneven, leading to potential fixing failures of toner images due to the heat generation state of adjacent blocks, particularly affecting the edge regions and causing temperature rises in non-sheet-passing portions beyond their withstanding limits.
Innovation Solution
The implementation of a heater with independently controllable heating blocks and strategically placed temperature detection elements, where thermistors are arranged to detect temperature in both center and edge regions, allowing for precise control of heat generation distribution to maintain even temperature across the blocks and prevent excessive temperature rises in non-sheet-passing areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If heating blocks are divided and independently controlled to suppress temperature rise in non-sheet-passing portions, then temperature control precision is improved, but temperature distribution uniformity deteriorates due to heat generation state of adjacent blocks affecting edge regions
Solution Approach 1:
The patent applies local quality by dividing the heating block into multiple independent heating regions (first heating block, second heating block, etc.) that can be controlled separately. Each heating region has its own temperature detection element, allowing localized temperature control to compensate for heat interference from adjacent blocks, thus maintaining temperature distribution uniformity while achieving precise temperature control.
Solution Approach 2:
The patent implements feedback control by providing temperature detection elements within each heating block that detect the temperature of adjacent heating blocks. This temperature information is fed back to the control unit, which adjusts the heat generation of each block independently to maintain uniform temperature distribution across the entire heating surface, resolving the temperature unevenness caused by adjacent block heat generation.
2Reliability
If heating blocks are operated independently to prevent temperature rise in non-sheet-passing portions, then reliability is improved, but device complexity increases due to multiple temperature detection elements and control mechanisms
Solution Approach 1:
The patent applies segmentation by dividing the heating block into multiple independent heating regions, each with its own temperature detection element. This segmentation allows independent control of each heating region, enabling reliable temperature management in non-sheet-passing portions while maintaining a relatively simple overall structure through modular design.
Solution Approach 2:
The patent implements multi-functionality by having temperature detection elements serve dual purposes: detecting the temperature of their own heating block and simultaneously detecting the temperature of adjacent heating blocks. This universal detection capability reduces the total number of sensors needed, thereby reducing device complexity while maintaining reliable temperature control.
3Measurement precision
If temperature detection elements are placed in heating blocks to detect temperature distribution, then measurement precision is improved, but the heating block structure becomes more complex
Solution Approach 1:
The patent applies merging by integrating temperature detection elements directly into the heating block structure, combining the heating and temperature detection functions into a single integrated unit. This integration achieves precise temperature distribution measurement while minimizing additional structural complexity by eliminating separate mounting structures and wiring harnesses.
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 ensures even temperature distribution along the heating blocks, preventing image defects and excessive temperature rises in non-sheet-passing regions, thereby enhancing the reliability of the image heating process.
Implementation Method 1
a plurality of heating blocks that are provided on the substrate and generate heat upon power supply
Implementation Method 2
a plurality of temperature detection elements are provided in at least one of the plurality of heating blocks
Data Source
AI summary
A heater includes a plurality of heating blocks in a substrate having a plurality of temperature detection elements disposed therein. In a case where one of the heating blocks is caused to generate heat alone, temperature distribution of the heating block in a longitudinal direction is inclined from a center part to an edge. One of the plurality of temperature detection elements is arranged in a region in which the temperature distribution is inclined.