Light Scanning Device Vibration Suppression
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Solution Overview
Problem
High-speed image forming apparatuses face challenges in maintaining high-quality printing due to vibrations from rotating motors and drivers, which affect the precision of beam irradiation in light scanning units, especially in tandem systems with multiple optical parts.
Innovation Solution
A light scanning device with a baseplate configuration that alternates between thick and thin vertical sections to position optical elements at nodes of vibration, suppressing resonance and vibration propagation from the polygon motor, and incorporating rib structures to reduce vibration amplitude and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical parts are arranged at positions with low vibrations or away from antinodes of vibrations, then writing quality is improved, but the light scan unit becomes bulky and cannot be effectively managed in tandem systems with multiple beams
Solution Approach 1:
The baseplate is designed with non-uniform thickness, having thick portions at locations where optical parts are mounted and thin portions elsewhere. This local variation in thickness provides vibration suppression precisely where needed (at optical component attachment points) while keeping the overall structure compact and manageable in tandem systems.
2Measurement precision
If a fixed optical path length is used for write operation, then beam irradiation position is predetermined, but vibrations from polygon motor or apparatus driver cause multiple mirrors to be placed at resonance points
Solution Approach 1:
The baseplate thickness parameter is varied to change the resonant frequency characteristics of the light scan unit. By making the baseplate thicker at specific locations, the resonant frequency is shifted away from the operating frequency of the polygon motor, thereby avoiding resonance conditions that would cause harmful vibrations affecting beam irradiation position.
3Reliability
If passive methods such as arranging optical parts at positions with low vibrations are used, then vibration suppression is achieved, but it becomes ineffective in bulky tandem systems with multiple optical parts
Solution Approach 1:
The baseplate incorporates localized thick portions specifically at the attachment locations of optical components in tandem systems. This allows effective vibration suppression for multiple optical parts without requiring the entire light scan unit to be oversized, thereby maintaining productivity in high-speed tandem image forming apparatuses.
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 suppresses vibrations in the optical system, enhancing print quality by ensuring precise beam alignment and reducing noise, even in bulky tandem systems with multiple optical parts.
Implementation Method 1
a polygon mirror for deflecting the plural beams by reflection of an identical facet thereof
Implementation Method 2
the baseplate is formed so that vertical-sectionally thick portions, which are made large in the vertical section and vertical-sectionally thin portions, which are made thin in the vertical section, are alternately formed from the position where the polygon mirror is attached toward the positions of attachment of the optical elements
Data Source
AI summary
In an exposure unit including: a laser scanning unit emitting a multiple number of beams; a polygon mirror for deflecting the multiple beams by reflection with the same facet; an optical system including optical elements for leading the beams correspondingly to a multiple number of photoreceptor drums laid out along an auxiliary scan direction, the bottom of a casing of the exposure unit to which the polygon mirror and the optical elements arranged along the directions of the beams emitted from the polygon mirror are attached is constructed so that the attachment portions of individual optical elements for each beam are differentiated in thickness from the areas where no attachment portion is formed.