Optical Scanner Housing Layout for Dust-Resistant Beam Apertures
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Solution Overview
Problem
The challenge in optical scanning devices is the increased risk of dust entry due to larger apertures caused by the mold structure, which degrades image quality in compact image forming apparatuses.
Innovation Solution
The optical scanning device incorporates a holding unit with a side wall extending in the axial direction, featuring a diaphragm to restrict the incident beam, and uses an inclined core mold structure to minimize aperture size, enhancing dust-proof performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the imaging lens and reflection mirror are disposed near the deflector to shorten the distance between photosensitive drums, then the image forming apparatus can be made smaller, but the aperture size in the holding unit increases causing dust to enter the housing
Solution Approach 1:
The aperture diaphragm is arranged on the side wall of the holding unit rather than in the front surface, changing the spatial dimension of aperture placement. This allows the aperture to be positioned away from the direct light path while still serving its beam restriction function, thereby preventing dust entry through the front aperture while maintaining the compact optical component arrangement
Solution Approach 2:
The aperture function is extracted from the front surface of the holding unit and relocated to the side wall. By separating the aperture placement from the front surface, the design eliminates the need for a large front aperture while maintaining beam restriction capability, thus preventing dust entry while keeping optical components compact
2Ease of operation
If a large aperture is arranged in the holding unit to accommodate the optical components, then the optical components can be held properly, but dust is likely to enter the housing from the outside
Solution Approach 1:
The aperture diaphragm is positioned on the side wall of the holding unit instead of the front surface, utilizing a different spatial dimension. This relocation maintains the holding function for optical components while eliminating the large front aperture that would allow dust entry
Solution Approach 2:
The side wall aperture diaphragm acts as an intermediary structure that provides beam restriction functionality without requiring a large front aperture. This intermediary placement on the side wall serves both the holding requirement and the dust prevention requirement simultaneously
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
This configuration reduces dust entry, improving image quality by minimizing aperture size and airflow, thereby enhancing the dust-proof performance of the device.
Implementation Method 1
a diaphragm configured to restrict an incident beam to the rotary polygon mirror from the light source is arranged on the side wall
Implementation Method 2
a rotary polygon mirror configured to deflect a light beam to be emitted from the light source
Implementation Method 3
an imaging lens focuses the deflected laser beam to form an image on a photosensitive drum
Data Source
AI summary
An optical scanning device includes a light source, a rotary polygon mirror configured to deflect a light beam from the light source, a scanning lens through which the light beam passes, a reflection mirror configured to reflect and guide the light beam to a surface to be scanned and having an elongated shape in a longitudinal direction, and a casing configured to support the light source, the rotary polygon mirror, the scanning lens, and the reflection mirror, wherein the casing includes a pair of holding units configured to hold both ends of at least one of the scanning lens or the reflection mirror in the longitudinal direction, the holding unit closer to the light source has a side wall extending in the axial direction from a bottom of the casing, and, on the side wall, a diaphragm configured to restrict an incident beam to the rotary polygon mirror is arranged.