Optical Scanning Device Seal Member Gate Positioning
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Solution Overview
Problem
The injection-molding of seal members in optical scanning devices often results in residual runner portions that can block light paths or contact optical components, leading to potential image failures and requiring additional processing steps for removal.
Innovation Solution
The seal member is injection-molded with a channel on the cover that positions the gate outside the light path area, ensuring the seal member is sandwiched between the cover and the optical housing without obstructing light paths, eliminating the need for complex assembly and additional processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the seal member is injection-molded on the cover, then the assembling process is simplified and sealability is ensured, but residual runner portions protrude and may block light paths or contact optical components
Solution Approach 1:
The harmful runner portions are extracted and removed through a post-molding cutting process. The patent employs an automated cutting device that precisely removes protruding runner portions after injection molding, eliminating the harmful effect of light path blockage while preserving the manufacturing simplicity of injection molding.
Solution Approach 2:
The gate position is preliminarily designed during the mold design phase to minimize runner portion protrusion. The cutting device is also preliminarily configured with predetermined cutting positions based on the expected runner portion locations, enabling automated removal without complex real-time detection.
2Ease of manufacture
If the seal member is injection-molded on the cover, then the assembling process is simplified, but additional processing steps are required to remove runner portions
Solution Approach 1:
The manual or complex mechanical process of runner portion removal is replaced with an automated cutting device that uses predetermined cutting positions. This substitution maintains the simplicity of injection molding while efficiently removing the need for additional complex processing steps, thereby preserving productivity.
Solution Approach 2:
The cutting device parameters (cutting depth, cutting position, cutting speed) are optimized based on the specific runner portion characteristics. By adjusting these parameters, the cutting process becomes a simple, fast operation that does not significantly impact overall manufacturing productivity.
3Ease of manufacture
If the gate is positioned for injection molding, then the seal member can be formed, but the runner portion may obstruct the light path area
Solution Approach 1:
The obstructing runner portions are extracted and removed after molding, separating the gate positioning function from the light path clearance requirement. This allows the gate to be positioned for optimal injection molding without compromising light path positioning, as the harmful runner portions are subsequently removed.
Solution Approach 2:
The seal member manufacturing process is segmented into two independent stages: injection molding with gate positioning optimized for manufacturing, and subsequent runner portion removal optimized for light path clearance. This segmentation allows each stage to be optimized independently without compromising the other.
Data Source
AI summary
A seal member is injection-molded with a simple structure that needs no complicated assembling process.An optical scanning device 21 includes a light source unit 202 from which a light beam is emitted; a rotating polygon mirror 203 that deflects the light beam such that the light beam emitted from the light source unit 202 is scanned over a photosensitive member; an optical component that directs the light beam deflected by the rotating polygon mirror 203 onto the photosensitive member; an optical housing 20 that contains the light source unit 202, the rotating polygon mirror 203, and the optical component; and a cover 30 that covers an opening of the optical housing 20. The cover 30 includes a seal member 31a molded such that the seal member 31a is sandwiched between the cover 30 and a side wall of the optical housing 20, a gate 31a from which hot melt is injected, and a channel through which the hot melt flows to form the seal member 31a such that the seal member 31a is sandwiched between the side wall of the optical housing 20 and the cover 30. The gate 31a is provided outside a light path area for the light beam when viewed in a direction of a rotational axis of the rotating polygon mirror 203.