Asymmetric Mirror Unit Design for Exposure Devices
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Solution Overview
Problem
Conventional mirror units in exposure devices for image forming apparatuses suffer from twisted rotation during angle adjustment, leading to accuracy issues in optical axis alignment and potential pitch unevenness in images.
Innovation Solution
A mirror unit design with one support point on the longitudinal end and two on the width end, positioned on the scanning optical axis, with a movable adjusting structure, ensuring the center of gravity remains within a triangular area formed by the support points, preventing twisted rotation and allowing precise angle adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the mirror is supported at three points with the rotary axis on the scanning optical axis, then the angle adjustment is simplified, but the center of gravity falls on the rotary axis causing twisted rotation and vibration
Solution Approach 1:
The patent positions the three support points asymmetrically relative to the mirror's center of gravity. Specifically, the support points form a triangle where the center of gravity lies within the triangle but not on the rotary axis. This asymmetric arrangement prevents twisted rotation during angle adjustment while maintaining ease of operation.
Solution Approach 2:
The patent resolves the contradiction by moving the problem from a 1D linear arrangement (rotary axis passing through center of gravity) to a 2D triangular arrangement of support points. The center of gravity is positioned within the triangular area formed by the three support points, creating a stable configuration that prevents vibration and twisted rotation.
2Manufacturing precision
If the mirror rotary axis is shifted parallel to the scanning optical axis to avoid twisted rotation, then vibration is reduced, but the support point must lean from the center causing complexity in positioning
Solution Approach 1:
The patent employs asymmetric positioning of support points relative to the mirror's center and scanning optical axis. The support points are arranged in a triangle with the center of gravity inside, but the triangle itself is positioned asymmetrically. This resolves the contradiction by preventing twisted rotation without requiring the support structure to be perfectly symmetric or centered.
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 design enhances the accuracy of image formation by preventing twisted rotation and maintaining the center of gravity within a stable triangular area, thereby improving image quality and exposure precision.
Implementation Method 1
a light flux emitted from a light source is reflected on the mirror to be projected on the surface of the aforesaid photoreceptor drum surface
Data Source
AI summary
A mirror unit of an exposure device includes: a mirror having support points including one support point on one end portion in a longitudinal direction thereof and two support points at two portions in a width direction perpendicular to the longitudinal direction on the other end portion thereof; and a mirror base member that holds the mirror in a way to support the mirror at the three support points, wherein the mirror is arranged so that the support point on a side of the one support point and a support point on one side of the two support points is positioned on a scanning optical axis, and so that the longitudinal direction is tilted from the scanning optical axis in the width direction.