Four-Sided Polygon Mirror for Laser Beam Deflection
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Solution Overview
Problem
Existing optical deflectors used in color image forming apparatuses face issues with vibration due to temperature changes and centrifugal forces, leading to increased power consumption and manufacturing complexity, particularly with two-level polygon mirror configurations.
Innovation Solution
A four-sided polygon mirror with continuous reflection surfaces, made from materials with specific Young's modulus ranges, is used, reducing deformation and windage loss, and allowing for easier processing and assembly, thereby minimizing environmental burdens and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a two-level polygon mirror configuration is used to deflect multiple laser beams, then the optical deflector can handle multiple beams, but the mass of the polygon mirror increases leading to significant vibration during high-speed rotation
Solution Approach 1:
The invention divides the polygon mirror into multiple independent single-level mirrors arranged vertically, each deflecting a specific laser beam. This segmentation reduces the mass of each individual mirror while maintaining the capability to deflect multiple beams simultaneously.
Solution Approach 2:
The invention transitions from a horizontal two-level configuration to a vertical arrangement of multiple single-level mirrors. This dimensional change allows multiple mirrors to be stacked along the rotational axis without increasing the radial mass distribution, reducing vibration during rotation.
2Speed
If a thick mirror configuration is used to increase the reflection surface area, then the optical deflector can handle high-speed rotation, but windage loss increases leading to higher power consumption
Solution Approach 1:
The invention uses thin film mirrors instead of thick mirrors, reducing the mass and surface area of each mirror. This reduction decreases windage loss during high-speed rotation, thereby lowering power consumption while maintaining the required rotation speed.
3Speed
If a double mirror configuration is used to increase the reflection surface area, then the optical deflector can handle high-speed rotation, but the reference plane and optical face alignment require high precision processing increasing manufacturing cost
Solution Approach 1:
The invention segments the mirror system into multiple independent single-level mirrors, each with its own reference plane. This eliminates the need for high-precision alignment between mirrors, as each mirror can be independently mounted and adjusted, significantly reducing manufacturing complexity and cost.
4Strength
If polygon mirrors are fixed to a rotating shaft by a leaf spring member, then the mirrors can be securely attached, but temperature rise and centrifugal force cause the mirrors to shift leading to vibration
Solution Approach 1:
The invention changes the fixing method from elastic deformation (leaf spring) to rigid fixation, eliminating the compliance that allows mirror shift under temperature and centrifugal force. This ensures stable mirror positioning during high-speed rotation.
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
The solution reduces deformation caused by centrifugal forces, shortens the starting time of the rotary member, and decreases power consumption during operation, while also simplifying the manufacturing process and reducing noise.
Implementation Method 1
a polygon mirror having four sides arranged about a rotational axis direction of the rotary member, wherein each of the four sides is a continuous plane having a plurality of effective reflection areas separated from each other in a rotational axis direction
Implementation Method 2
the temperature rise and centrifugal force generated by high speed rotation of the rotating shaft causes the fixed polygon mirrors to slightly shift
Data Source
AI summary
An optical deflector including a rotary member supported by a bearing shaft and rotatively driven by a motor for deflecting a plurality of laser beams separated from each other in a rotational axis direction of the rotary member is disclosed. The optical deflector includes a polygon mirror having four sides arranged about the rotational axis direction. Each of the four sides is a continuous plane having a plurality of effective reflection areas separated from each other in the rotational axis direction.