Fixing Device Heat-Conductive Member for Uniform Temperature
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Solution Overview
Problem
The existing heating devices in image forming devices experience a decrease in fixing temperature at the opposite end portions when processing maximum-size sheets, leading to inefficient heat distribution.
Innovation Solution
A fixing device with a cylindrical belt and a heat-conductive member is used, where the heat-conductive member has specific contact and non-contact portions to manage heat conductivity between the heater and the holder, ensuring uniform heat distribution across the maximum-size-sheet passing region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal plate is disposed over an entire region of the heater, then heat conduction is improved, but fixing temperature decreases at opposite end portions
Solution Approach 1:
The heat-conductive member is divided into multiple regions with different contact characteristics: a contact portion that contacts the heater and non-contact portions that do not contact the heater. This segmentation allows different parts of the heat-conductive member to perform different functions - the contact portion conducts heat effectively while the non-contact portions prevent excessive heat conduction to end portions, thereby resolving the temperature uniformity issue
Solution Approach 2:
Different regions of the heat-conductive member are given different thermal conduction properties through selective contact with the heater. The contact portion has high heat conduction to ensure adequate heating, while the non-contact portions have reduced heat conduction to prevent temperature drop at end portions. This local differentiation of thermal properties resolves the contradiction between overall heat conduction and temperature uniformity
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 prevents or reduces temperature decreases at the end portions of the maximum-size-sheet passing region, maintaining uniform fixing temperatures and enhancing the heating efficiency for larger sheets.
Implementation Method 1
a heat-conductive member disposed between the heater and the holder, the heat-conductive member having a heat conductivity higher than a heat conductivity of the base plate
Data Source
AI summary
A fixing device, including: a cylindrical belt; a heater including a base plate and a heating element provided on the base plate; a holder supporting the heater; and a heat-conductive member disposed between the heater and the holder and having a higher heat conductivity than the base plate, wherein the heat-conductive member includes: a contact portion opposed to a region of the base plate between a one-side end and an other-side end of the heating element in the first direction; a first non-contact portion opposed to a region of the base plate in which the one-side end is located, the first side portion being not in contact with the heater, and a second non-contact portion opposed to a region of the base plate in which the other-side end is located, the second side portion being not in contact with the contact portion.