Optical Scanning Duct for Polygon Mirror Heat Dissipation
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Solution Overview
Problem
Existing heat dissipation structures in optical scanning devices for electrophotographic image forming devices face challenges in maintaining high accuracy of polygon mirror positioning and efficient heat release from polygon motors and driver circuits, especially at increased rotation speeds, leading to potential overheating and distortion issues.
Innovation Solution
The design incorporates a housing with a duct system that surrounds the deflector and its circumference, featuring an air inlet and outlet, and a positioning member that secures the rotation axis of the polygon mirror, ensuring a controlled air flow path for efficient heat dissipation without compromising the positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotation speed of polygon mirrors is increased to increase area scanned per unit time, then productivity is improved, but heat amount from polygon motors and driver circuits increases causing overheating and distortion
Solution Approach 1:
The housing is divided into a first housing and a second housing that are separable from each other. The duct is formed by the combination of these two housings, allowing the heat dissipation path to be segmented and directed away from the optical system. This segmentation enables independent optimization of cooling paths for the motor while protecting the optical elements.
Solution Approach 2:
A duct is introduced as an intermediary structure between the heat-generating polygon motor and the optical system. The duct guides air flow to carry heat away from the motor while the positioning member acts as a thermal barrier, preventing direct heat transfer to the optical elements. This intermediary structure resolves the contradiction by providing a dedicated heat dissipation path.
2Temperature
If a duct is used to guide air flow for heat dissipation from polygon motor, then temperature control is improved, but positioning accuracy of polygon mirror may be compromised due to thermal distortion of housing
Solution Approach 1:
The heat dissipation function is extracted from the main housing structure by introducing a separate duct system. The duct is formed by the space between the first and second housings, allowing air to flow through and carry heat away from the motor without requiring the main housing to be directly involved in heat dissipation. This extraction prevents thermal distortion of the housing that would affect positioning accuracy.
Solution Approach 2:
The positioning member is designed with sufficient heat resistance to act as a thermal barrier before heat can reach the optical system. By providing this thermal cushioning in advance, the patent prevents heat from the motor from causing thermal distortion that would compromise the positioning accuracy of the polygon mirror.
3Temperature
If gas flows are forced directly onto polygon mirror for cooling, then heat dissipation is improved, but rotation axis stability deteriorates due to turbulence and wobbling
Solution Approach 1:
Different regions of the housing are assigned different functions: the duct region handles heat dissipation through air flow, while the region containing the optical system and polygon mirror is kept thermally isolated. The positioning member provides localized thermal barrier protection to the polygon mirror, allowing cooling of the motor without subjecting the mirror to turbulent gas flows that would destabilize its rotation axis.
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 solution effectively maintains high positioning accuracy of the polygon mirror and enhances heat dissipation efficiency, preventing overheating and distortion, even at increased rotation speeds, thus improving the productivity and image quality of image forming apparatuses.
Implementation Method 1
the duct allows air flows to carry heat from the motor to the outside of the housing
Implementation Method 2
a positioning member shaped as a pillar that protrudes from the floor towards the deflector and has a tip to contact with the deflector to locate the rotation axis of the polygon mirror at a position relative to the housing, and to limit a clearance between the supporting section and the floor to secure therein a flow path of the gas from the inlet
Implementation Method 3
the duct surrounding a space from the deflector and its circumference to the outlet in insulation from the optical system
Data Source
AI summary
An optical scanning device has a housing in which a duct surrounds a space from the deflector and its circumference to an outlet in insulation from the optical system, and guides gas from an inlet to the space. A positioning member is shaped as a pillar that protrudes from the floor of the duct towards the deflector and has a tip to contact with the deflector to locate the rotation axis of the polygon mirror at a position relative to the housing. The positioning member further limits a clearance between an outer surface of the deflector and the floor to secure therein a flow path of the gas.