Shutter Projection Design for Fixing Apparatus Guiding Surface Protection
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Solution Overview
Problem
Conventional fixing apparatuses with shutters in electrophotographic image forming devices risk damaging the recording-medium guiding surface due to shutter bending or warping, leading to reduced accuracy and potential paper jams, which can be costly to prevent through increased dimensional accuracy or rigidity.
Innovation Solution
A fixing apparatus design featuring a guiding member with ribs and a shutter with projections, where the clearance between the rib and the shutter is larger than between the guiding member and the projection, ensuring the shutter does not damage the guiding surface even when deformed, and allowing for cost-effective production without metallic reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shutter and components are increased in dimensional accuracy and rigidity to prevent bending or warping, then the reliability of the recording-medium guiding surface is improved, but the manufacturing cost increases
Solution Approach 1:
A projection is added to the shutter as an intermediary protective element. This projection extends toward the guiding member and acts as a sacrificial component that can contact the guiding surface without causing damage, even when the shutter bends or warps. The projection serves as a mediator between the shutter and the guiding surface, protecting the critical recording-medium guiding surface from damage while allowing the shutter to be manufactured with lower precision and cost-effective materials.
2Ease of manufacture
If the shutter is made with lower dimensional accuracy and rigidity to reduce manufacturing cost, then the ease of manufacture is improved, but the shutter may bend or warp and damage the recording-medium guiding surface, reducing reliability
Solution Approach 1:
The projection on the shutter is designed as a sacrificial, replaceable element that can be manufactured at low cost. When the shutter bends or warps due to lower rigidity or external forces, the projection serves as the first point of contact with the guiding surface, absorbing the potential damage. This allows the use of cost-effective materials and manufacturing processes for the shutter while maintaining protection of the guiding surface through the disposable-like projection element.
3Measurement precision
If the clearance between the shutter and guiding member is reduced to improve positioning accuracy, then the measurement precision is improved, but the risk of contact and damage to the guiding surface increases when the shutter deforms
Solution Approach 1:
The projection acts as an intermediary buffer zone between the shutter body and the guiding surface. It allows for a larger overall clearance between the shutter and guiding member, reducing the risk of damage when deformation occurs, while still maintaining adequate positioning accuracy for recording medium conveyance through the rib structures on the guiding member.
Data Source
AI summary
A fixing apparatus fixes an image formed on a recording material and includes a guiding member for guiding movement of the recording material, provided in a recording material passing opening of the apparatus, a rib projecting from a recording-material passing surface of the guiding member, for being contacted by the recording material, a shutter provided at a position opposing the guiding member and movable between a position for opening the passing opening and a position closing the passing opening, and a projection provided at a position of the shutter opposing a portion of the guiding member not having the rib with respect to a direction perpendicular to a recording material feeding direction. When the shutter takes the closing position, the clearance between the rib and the shutter is larger than the clearance between the guiding member and the projection.