Chassis Seal Member Design for Optical Scanning Devices
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Solution Overview
Problem
Conventional optical scanning devices in electrophotographic image forming apparatuses face issues with sealing performance due to complex or fragmented seal members, which can lead to reduced yield rates, increased costs, and the risk of faulty images from seal member fragmentation caused by hydrolysis.
Innovation Solution
A chassis structure with a simple configuration featuring a cover member and a viscoelastic seal member that is compressed and deformed to seal gaps, with holes in the cover member to ensure secure attachment and prevent separation, eliminating the need for complex joint lines and reducing the risk of hydrolysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sponge member seal is used between the optical housing and cover member, then sealing performance is improved, but the seal member becomes complicated and is divided into multiple pieces, resulting in low yield rate and increased costs
Solution Approach 1:
The patent combines multiple separate seal members into a single integrated seal member that seals both the first gap (between optical housing and cover member) and the second gap (between optical housing and chassis). This merging eliminates joint lines between separate seals, prevents fragmentation issues, and simplifies the overall seal configuration while maintaining comprehensive sealing performance.
Solution Approach 2:
The integrated seal member is designed with different sections having different molding heights: a first section with greater molding height for sealing the first gap, and a second section with lesser molding height for sealing the second gap. This segmentation within a unified structure allows optimized sealing for each gap while maintaining the benefits of an integrated design.
2Reliability
If a sponge member seal is used, then sealing is achieved, but joint lines create clearances that reduce sealing capability
Solution Approach 1:
By integrating multiple sealing functions into a single seal member, the patent eliminates the joint lines that would otherwise exist between separate seal pieces. This removes the source of clearances and maintains continuous sealing contact with the optical housing and cover member, thereby preserving sealing capability.
3Reliability
If a sponge member is used, then sealing is provided, but the sponge member may fragment due to hydrolysis from water over time, entering as foreign matter and causing faulty images
Solution Approach 1:
The patent replaces the traditional sponge member (which degrades through hydrolysis) with a resin-based seal member that offers superior long-term stability and resistance to fragmentation. While the resin material may require different sealing mechanics, it eliminates the hydrolysis problem that causes sponge degradation over time.
Solution Approach 2:
The seal member is constructed from resin material that combines sealing elasticity with hydrolysis resistance. This composite approach maintains the necessary compliance for sealing while providing long-term durability and preventing the formation of foreign matter that would cause image defects.
4Ease of manufacture
If the seal member molding height is insufficient, then assembly is easier, but the seal member cannot effectively seal the gap between chassis and cover member
Solution Approach 1:
The seal member is designed with non-uniform molding heights: a first section with greater molding height positioned to seal the first gap (optical housing to cover member), and a second section with lesser molding height for the second gap (optical housing to chassis). This local differentiation ensures each section has sufficient height for its specific sealing requirement while maintaining overall assembly feasibility.
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 provides enhanced sealing performance over time, reducing the occurrence of faulty images and maintaining the integrity of the seal, while also simplifying the configuration and reducing costs by preventing seal member fragmentation and improving yield rates.
Implementation Method 1
a seal member that, when the cover member is attached to the chassis, is compressed and deformed so as to seal a gap between the cover member and the chassis
Implementation Method 2
a viscoelastic seal member that is compressed and deformed to seal gaps
Data Source
Figure 1
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AI summary
A chassis structure includes: a chassis that houses a component used for an image forming apparatus inside and that includes an opening; a cover member that covers the opening of the chassis; and a seal member that is provided between the cover member and the chassis and that, when the cover member is attached to the chassis, is compressed and deformed so as to seal a gap between the cover member and the chassis. An attached section of the cover member to which the seal member is attached is provided with a hole.