Curved Pressurizing Roller for Uniform Toner Fixing
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face challenges in effectively fixing toner images onto recording paper without causing paper wrinkles or waves, and ensuring proper detachability of the paper.
Innovation Solution
A fixing device with a curved pressurizing roller and a secured pad having a crown-shaped pressing surface, where the center portion projects more towards the roller than the end portions, is used to form a nip part that applies varying tension to the fixing belt, ensuring uniform heat and pressure distribution for efficient toner fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional pressurizing roller with uniform diameter is used, then the structure is simple, but paper wrinkles and waves occur during fixing
Solution Approach 1:
The pressurizing roller is designed with a curved outer peripheral surface where the center portion has a smaller diameter than the end portions, creating a crown-shaped profile. This curvature variation allows the roller to apply non-uniform pressure distribution that compensates for belt tension variations, preventing paper wrinkles and waves during the fixing process.
2Manufacturing precision
If the center portion of the pressing surface projects more than end portions, then uniform heat and pressure distribution is achieved, but the secured member structure becomes more complex
Solution Approach 1:
The pressing surface of the secured member is designed with varying projection heights along its length, where the center portion projects more than the end portions. This creates different local contact characteristics that correspond to different tension regions of the fixing belt, achieving uniform heat and pressure distribution through localized structural variation rather than uniform design.
3Manufacturing precision
If varying tension is applied to the fixing belt, then toner fixation quality improves, but the risk of paper detachment problems increases
Solution Approach 1:
The system dynamically adjusts the tension parameter of the fixing belt by varying the projection height of the secured member's pressing surface. The center portion with greater projection creates higher tension in the mid-section of the belt for improved toner fixation, while the end portions with smaller projections maintain lower tension to ensure proper paper detachment, achieving both fixation quality and reliability through parameter variation.
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
The solution prevents the occurrence of paper wrinkles and waves, ensuring good peeling and detachment of the paper, as demonstrated in experimental examples, while maintaining image quality and operational efficiency.
Implementation Method 1
a rotary pressurizing roller that includes an elastic layer that is elastically deformed when the belt member is pressed against a pressing surface of the secured member to form a fixing part
Implementation Method 2
a heating unit that heats the belt member
Data Source
AI summary
A fixing device includes an endless belt member, a secured member disposed to contact the belt member, a heating unit that heats the belt member, and a rotary pressurizing roller including an elastic layer that is elastically deformed when the belt member is pressed against a pressing surface of the secured member to form a fixing part. The pressurizing roller is curved such that a center portion is smaller in outside diameter than end portions along the axial direction. The pressing surface is curved such that a center portion projects toward the pressurizing roller more than end portions along the longitudinal direction. On the pressing surface, an amount of projection of the center portion with respect to the end portions along the longitudinal direction is set to be larger on an output side than on an input side of the fixing part along a moving direction of the belt member.