Fixing Device Heater Thermal Uniformity
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Solution Overview
Problem
Conventional fixing devices for image forming apparatuses experience temperature non-uniformity and deformation due to asymmetrical arrangement of heating members and soaking members, leading to thermal gradients and strain on the heater board.
Innovation Solution
A fixing device with a heater having elongated substrates and heat generating members of varying lengths, where a soaking member with a positioning portion is arranged between the heater and holder to equalize temperature and reduce thermal gradients, with the positioning portion positioned outside the shorter heat generating member area but inside the longer member area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a positioning portion is formed by bending a portion of the aluminum plate to fix the soaking member to the heater holder, then the soaking member can be positioned and fixed, but the bent portion has greater heat capacity causing localized temperature differences and thermal gradients that deform the heater board
Solution Approach 1:
The patent extracts the positioning function from the main body of the soaking member by providing a separate positioning groove in the heater holder. This separates the positioning portion from the heat-conducting aluminum plate, preventing the positioning structure from interfering with thermal uniformity while maintaining positioning stability.
Solution Approach 2:
The heater holder acts as an intermediary component that provides the positioning groove, mediating between the soaking member and the heater board. This allows the soaking member to be positioned without requiring structural modifications to the aluminum plate itself, thus avoiding localized heat capacity changes.
2Adaptability or versatility
If heating members are arranged asymmetrically to match different recording material widths, then the device can handle various paper sizes, but temperature non-uniformity occurs on the heater board causing deformation
Solution Approach 1:
The patent applies local quality by providing a soaking member with high thermal conductivity specifically at the heater board position. This localized thermal management compensates for the asymmetric heating pattern, ensuring temperature uniformity in the critical heating region while maintaining adaptability to different paper sizes through selective heating member activation.
Solution Approach 2:
The soaking member uses aluminum, a material with high thermal conductivity, to create a thermal composite structure. This aluminum plate distributes heat evenly across the heater board surface, counteracting the temperature non-uniformity caused by asymmetric heating member arrangements while allowing versatile paper size handling.
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 effectively reduces temperature gradients and deformation of the heater board by evenly distributing heat and stabilizing the thermal expansion, enhancing the fixing process's reliability and efficiency.
Implementation Method 1
a soaking member configured to uniformalize a temperature of the substrate
Implementation Method 2
a heater provided with an elongated substrate, a first heat generating member, a second heat generating member
Data Source
AI summary
A fixing device includes a substrate, a first heat generator, a second heat generator with a length in a longitudinal direction of the substrate equal to a length of the first heat generator; and a third heat generator with a length shorter than the lengths of the first and second heat generators, a soaking member with a positioning portion in the longitudinal direction. In a short side direction of the substrate, the first heat generator is arranged at one end side, the second heat generator is arranged at the other end side, and the third heat generator is arranged between the first and second heat generators. The soaking member is arranged between the heater and a holder in a thickness direction. As seen in the short side direction, the positioning portion is positioned outside of an area corresponding to the third heat generator and inside of an area corresponding to the first heat generator.