Fixing Device Pressure Lever Mechanism for Impact Mitigation
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Solution Overview
Problem
Conventional fixing devices in electrophotographic image forming apparatuses experience partial permanent deformation and generate an impact sound during pressure release, which is undesirable and needs to be mitigated.
Innovation Solution
A fixing device with a supporter and releaser mechanism that includes an engagement recess, slidable contact portion, and biasing member, allowing for controlled adjustment of biasing intensity to reduce impact during pressure contact and release, featuring a slidable contact portion with specific flat portions and angles to smoothly transition the releaser between pressure and release positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pressure release lever is operated to cancel pressure contact between roller members, then the pressure contact state is released, but collision sound and impact sound are generated
Solution Approach 1:
The patent introduces a cushioning member (elastic body) between the pressure release lever and the pressure lever to absorb impact energy before the collision occurs. This elastic body deforms during the pressure release operation, cushioning the impact and reducing the generated sound, directly applying the beforehand cushioning principle to solve the impact sound problem.
Solution Approach 2:
The cushioning member serves as an intermediary element between the pressure release lever and the pressure lever. Instead of direct contact causing impact sound, the cushioning member mediates the interaction by deforming elastically, thereby reducing the harmful impact sound while still enabling the pressure release function.
2Reliability
If the roller members are biased against each other with a pressure member for a long time, then pressure contact is maintained, but partial permanent deformation occurs in the elastic layer
Solution Approach 1:
The patent makes the pressure contact state adjustable and dynamic rather than fixed. The pressure release lever enables switching between pressure contact state (for reliable image fixing) and release state (to prevent permanent deformation). This dynamic adjustment capability resolves the contradiction by allowing the system to change its pressure contact characteristics based on operational needs.
Solution Approach 2:
The patent provides a mechanism (pressure release lever) that can be operated to cancel the pressure contact state before permanent deformation occurs in the elastic layer. This preliminary anti-action prevents the harmful effect by allowing periodic release of the biased state, counteracting the tendency toward permanent deformation while maintaining reliability during actual operation.
3Adaptability or versatility
If the engagement protrusion slides along the slidable contact portion, then biasing intensity is adjusted, but friction and resistance increase
Solution Approach 1:
The slidable contact portion is designed with specific local characteristics - a flat surface with predetermined smoothness in the sliding direction. This local quality optimization reduces friction during the sliding motion of the engagement protrusion, enabling biasing intensity adjustment while minimizing resistance and making operation easier.
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 effectively mitigates the impact sound and vibration during pressure contact and release, enabling easier operation and reducing wear on components, thus enhancing the operational stability and quietness of the fixing device.
Implementation Method 1
a biasing member which biases the supporter in a pressure contact direction
Implementation Method 2
the slidable contact portion includes a first flat portion extending in a direction of reducing the biasing force of the biasing member
Data Source
AI summary
In a fixing device of an image forming apparatus, a pressure lever includes an engagement recess for holding a pressure release lever at a pressure position where a biasing member is actuated, and the pressure release lever includes an engaging protrusion which can be engaged with the engagement recess. Also, the pressure lever includes a slidable contact portion adjacent to the engagement recess. The pressure releaser is capable of increasing or decreasing biasing intensity of the biasing member as the engagement protrusion is slid along the slidable contact portion by a biasing force of the biasing member between a state in which the pressure releaser is at the pressure position and a state in which the pressure releaser is at a release position for releasing pressure contact.