Fixing Belt Friction and Heat Equalizing Sheet
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Solution Overview
Problem
The existing fixing devices in image forming apparatuses face issues with torque increase due to frictional resistance, leading to increased motor size and power consumption, as well as non-uniform heat transfer and potential temperature increases in the fixing nip, which can cause deformation and shape changes, affecting the width of the fixing nip.
Innovation Solution
A fixing device is designed with an endless and rotatable fixing belt, a heating member, a pressure member, a pad member, a support member, a friction reducing sheet between the fixing belt and the pad member, and a heat equalizing sheet between the friction reducing sheet and the pad member to improve thermal uniformity and slidability while maintaining a uniform fixing nip width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a sliding sheet is used to reduce friction, then torque and power consumption are reduced, but thermal conductivity decreases causing non-uniform heat transfer
Solution Approach 1:
The patent applies a composite structure consisting of a sliding sheet layer and a heat equalizing sheet layer. The sliding sheet (fluororesin) provides low friction coefficient to reduce torque and power consumption, while the heat equalizing sheet (metal material with high thermal conductivity) compensates for the low thermal conductivity of the sliding sheet, ensuring uniform heat transfer across the fixing nip.
2Temperature
If solid heat equalizing members are used, then thermal conductance is improved, but deformation occurs due to thermal expansion differences
Solution Approach 1:
The patent uses a heat equalizing sheet in the form of a thin flexible sheet rather than a rigid solid member. This flexible sheet can deform elastically to accommodate thermal expansion differences between the sliding sheet and pad member, preventing shape changes and maintaining uniform fixing nip width while still providing effective heat equalization.
3Loss of energy
If a friction reducing sheet is added, then torque is reduced, but device complexity increases
Solution Approach 1:
The patent changes the friction parameter by introducing a sliding sheet with low friction coefficient (fluororesin material) between the fixing belt and pad member. This material parameter change directly reduces frictional resistance and torque without requiring complex control mechanisms or additional active components, thus minimizing the increase in device complexity.
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 reduces frictional resistance, maintains a uniform fixing nip width, and ensures effective heat transfer across the fixing nip, preventing temperature-related deformations and energy inefficiencies, thus enhancing the performance and reliability of the image forming apparatus.
Implementation Method 1
a friction reducing sheet that is provided between the fixing belt and the pad member and reduces friction with the fixing belt
Implementation Method 2
a heat equalizing sheet that is provided between the friction reducing sheet and the pad member and heats the fixing belt at the fixing nip uniformly in a width direction of a paper sheet passing through the fixing nip
Data Source
AI summary
A fixing device includes: a fixing belt that is endless and rotatable; a heating member that heats the fixing belt; a pressure member that is rotatable and presses the fixing belt from outside; a pad member that forms a fixing nip by sandwiching the fixing belt with the pressure member; a support member that supports the pad member; a friction reducing sheet that is provided between the fixing belt and the pad member and reduces friction with the fixing belt; and a heat equalizing sheet that is provided between the friction reducing sheet and the pad member and heats the fixing belt at the fixing nip uniformly in a width direction of a paper sheet passing through the fixing nip.