Optical Scanning Device Thermal Management via Housing Extraction
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Solution Overview
Problem
Optical scanning devices in image forming apparatuses face issues with positional displacement due to thermal expansion caused by heat generated from drive devices, affecting the accuracy of toner image superimposition.
Innovation Solution
The optical scanning device incorporates a housing design with a lower housing having an opened bottom surface and a raised area, featuring lead-out openings and a metal bottom plate member to facilitate heat radiation, which includes a heat radiation channel and duct for efficient cooling of the rotating polygon mirror.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a drive device is provided to rotate the polygon mirror, then the optical scanning function is achieved, but heat is generated causing thermal expansion and positional displacement of mounted components
Solution Approach 1:
The patent extracts the heat-generating drive device from the housing interior by providing a through-hole in the housing that allows the drive shaft to extend outward. This extraction removes the primary heat source from the enclosed space where precision optical components are mounted, thereby preventing thermal expansion-induced positional displacement while maintaining the scanning function.
Solution Approach 2:
The patent introduces an intermediary structure (the through-hole and extended drive shaft configuration) that allows the drive device to operate externally to the housing. This intermediary arrangement enables the drive mechanism to rotate the polygon mirror without being enclosed within the temperature-sensitive housing, thus mediating between the need for mechanical drive and the need for thermal stability.
2Reliability
If the housing is enclosed to protect internal components, then protection from dust and damage is achieved, but heat generated by the drive device accumulates causing thermal expansion
Solution Approach 1:
The drive device is extracted from the enclosed housing space by providing a through-hole that allows the drive shaft to extend outward. This extraction removes the heat-generating component from the enclosed environment, enabling the housing to remain protected and enclosed while preventing heat accumulation that would cause thermal expansion.
Solution Approach 2:
The housing structure is segmented to include a through-hole that creates a separation between the enclosed protected space (containing optical components) and the external drive mechanism. This segmentation allows the housing to maintain its protective enclosure function while isolating the thermal environment of the drive device from the sensitive internal components.
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 effectively releases heat generated by the rotating polygon mirror, preventing positional displacement due to thermal expansion and ensuring accurate scanning and image formation.
Implementation Method 1
the lower housing is provided with a bottom surface opening including an opened bottom surface between the rotating polygon mirror and the reflection mirror
Implementation Method 2
a housing is configured by a lower housing including an opened top part and an upper housing that covers the top part of the lower housing
Data Source
AI summary
To provide an optical scanning device including a lower housing including an opened top part, an upper housing that covers the top part of the lower housing, a rotating polygon mirror that reflects a beam, an fθ lens on which the beam reflected by the rotating polygon mirror is incident, and a reflection mirror that reflects the beam. The lower housing is provided with a bottom surface opening including an opened bottom surface between the rotating polygon mirror and the reflection mirror.