Optical Scanning Unit Cover Rib for Dust-Resistant Cooling
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Solution Overview
Problem
In image forming apparatuses, the increased heat generation from components like the polygonal mirror and fixing device leads to higher internal temperatures, causing thermal deformation and dust accumulation on optical components, which can reduce the transmittance and reflectance of scanning lenses, resulting in image density issues.
Innovation Solution
An image forming apparatus with an optical scanning unit that includes a rotatable polygonal mirror, an optical box, and a cover with a rib structure to direct airflow from a fan away from the light beam emitting port, reducing dust entry and deposition on optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a fan is used to cool the optical scanning apparatus, then heat dissipation is improved, but dust is deposited on optical components
Solution Approach 1:
The patent introduces an air passage as an intermediary structure that separates the cooling airflow path from the optical component area. The air passage allows hot air to be discharged without directly contacting the optical components, thus mediating between the cooling function and the dust prevention requirement
Solution Approach 2:
The optical box is segmented into distinct functional zones: an optical component housing area and a separate air passage area. This segmentation allows the cooling airflow to be directed through the air passage without passing over the optical components, resolving the contradiction between cooling and dust protection
2Volume of moving object
If the scanning lens is positioned near the emitting port for compact design, then device size is reduced, but dust directly deposits on the scanning lens
Solution Approach 1:
The patent resolves the spatial conflict by using vertical layering (another dimension) to separate functions. The scanning lens remains positioned near the emitting port for compactness, while the air passage is positioned above it to discharge airflow in a different spatial direction, preventing dust deposition on the lens
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 improves dust-proof performance by reducing dust accumulation on optical components, maintaining image density and preventing thermal deformation-related issues.
Implementation Method 1
a fan configured to cool an inside of the image forming apparatus
Implementation Method 2
a rotatable polygonal mirror configured to deflect the light beam emitted from the light source
Data Source
AI summary
An image forming apparatus for forming an image on a recording material includes a photosensitive member; an optical scanning unit including a light source, an optical box, and a cover; and a fan. The fan is provided so that air from the fan directly impinges on the cover of the optical scanning unit. As seen in a direction perpendicular to a rotational axis of the rotatable polygonal mirror, a rib extending from a top plate of the cover toward an optical box side is provided at a portion of the cover in the neighborhood of a light beam emitting port of the optical scanning unit. The cover is provided with an extended portion extended from the rib in a light beam emitting direction.