Multi-Radius Cam for Variable Nip Pressure Control
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Solution Overview
Problem
Existing fixing devices struggle to vary pressure at the nip between rotatable members with sufficient ease and precision, limiting their ability to accommodate different media types effectively.
Innovation Solution
A fixing device is designed with a cam having multiple contact states, including a first and second cam portion with different radial distances from the pivot axis, allowing for varying pressure adjustments by pivoting the cam and biasing member through multiple positions, enabling precise control of nip pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single cam surface is used to vary nip pressure, then the structure is simple, but the pressure adjustment precision and versatility are limited
Solution Approach 1:
The cam surface is segmented into multiple distinct cam portions (first cam portion and second cam portion) with different radial distances from the pivot axis. Each cam portion corresponds to a specific pressure level, allowing precise pressure adjustment by selecting which cam portion contacts the receiving surface, while maintaining a relatively simple overall cam structure.
Solution Approach 2:
Different portions of the cam have different local properties - specifically, different radial distances from the pivot axis. The first cam portion has a greater radial distance for higher pressure adjustment, while the second cam portion has a smaller radial distance for lower pressure adjustment, enabling precise local control of pressure characteristics.
2Adaptability or versatility
If multiple pressure positions are implemented with a single cam, then versatility is improved, but the torque required for position changes increases
Solution Approach 1:
The cam is designed to pivot dynamically between different positions, with each position corresponding to a different media type requirement. The spring provides dynamic biasing force that assists in returning the cam to default positions, reducing the torque needed for position changes while maintaining versatility across multiple pressure settings.
Solution Approach 2:
The cam structure allows changing the effective radial distance parameter by pivoting to different positions. When pivoting from the first cam portion to the second cam portion, the effective lever arm changes, which optimizes the torque characteristics for different operating conditions and reduces energy consumption during position transitions.
3Ease of operation
If the cam has multiple contact positions for pressure variation, then ease of operation is improved, but the device complexity increases
Solution Approach 1:
The receiving member is segmented with multiple distinct receiving surfaces (first receiving surface and second receiving surface) at different heights. This segmentation allows the cam to engage with different surfaces for different pressure levels, making operation easier through clear discrete positions while keeping the overall structure relatively simple through modular surface design.
Solution Approach 2:
The receiving surfaces are positioned at different heights in the vertical dimension, creating a multi-level engagement structure. This dimensional arrangement allows easy visual and tactile identification of different pressure positions, improving ease of operation while maintaining structural simplicity through vertical stacking rather than horizontal 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 solution allows for easier and more precise variation of nip pressure, accommodating various media types, from ordinary paper to thicker materials, while reducing the required torque for position changes, thus enhancing the device's versatility and operational efficiency.
Implementation Method 1
The cam may include a first cam portion and a second cam portion located at a different point from the first cam portion in an axial direction of the cam and having a radial distance from the pivot axis smaller than a radial distance of the first cam portion from the pivot axis
Implementation Method 2
The spring may include one end connected to the frame
Data Source
AI summary
A fixing device includes a frame including a joint, a first rotary body and supported at the frame, a second rotary body, a spring with one end connected to the frame, a support arm connected to the joint, the second rotary body, and another end of the spring, a cam pivotably connected to one of the frame and the support arm, and a receiving member. The cam includes a first cam portion, and a second cam portion located at a different point from the first cam portion in the axial direction and having a radial distance from the pivot axis smaller than a radial distance of the first cam portion from the pivot axis. The receiving member includes a first receiving surface and a second receiving surface, the second receiving surface having a different surface height than the first receiving surface in a radial direction from the pivot axis.