Optical Scanning System Spray Light Reduction
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Solution Overview
Problem
Existing optical scanning systems using plural light beams to scan multiple surfaces face challenges in maintaining a simple structure and avoiding rigid constraints on the shape of scanning lenses, which leads to issues with spray light causing poor quality printing.
Innovation Solution
The optical scanning system employs first and second light sources, a polygon mirror, and first to fourth scanning lenses, where the light beams are configured to pass through specific lenses and are focused at reference points to minimize spray light influence, ensuring a lateral magnification range of 2 to 3.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shading member is placed between the polygon mirror and scanning lenses to eliminate spray light, then spray light-induced printing defects are reduced, but device complexity and production cost increase
Solution Approach 1:
The patent removes the shading member from the optical path between the polygon mirror and scanning lenses, extracting the harmful element that caused complexity. Instead of blocking spray light with additional components, the invention uses careful positioning and angular control to allow the spray light to naturally avoid reaching the scanning lenses, thereby eliminating printing defects without increasing structural complexity
Solution Approach 2:
The patent introduces the scanning lens itself as an intermediary element that performs dual functions: focusing the main light beam for scanning and simultaneously blocking spray light through its angular positioning and surface geometry. The scanning lens acts as a mediator that prevents spray light from reaching the surface without requiring separate shading components
2Object-affected harmful factors
If the scanning lens surface is made convex towards the polygon mirror to prevent spray light reflection, then spray light is reduced, but lateral magnification increases and error sensitivity increases
Solution Approach 1:
The patent applies different surface curvature characteristics to different regions of the scanning lens. The object-side surface has a specific curvature radius (50mm to 200mm) optimized for blocking spray light, while the image-side surface has a different curvature radius (100mm to 500mm) optimized for focusing. This localized optimization allows spray light prevention without excessive lateral magnification, reducing error sensitivity in shape and position
Solution Approach 2:
The patent optimizes specific parameters of the scanning lens surfaces: object-side curvature radius between 50mm and 200mm, image-side curvature radius between 100mm and 500mm, and thickness between 1mm and 10mm. By carefully controlling these parameters, the system achieves spray light blocking while maintaining acceptable lateral magnification (2x to 3x) and minimizing error sensitivity
3Productivity
If plural light beams are used to scan multiple surfaces, then scanning productivity increases, but spray light from one beam affects other surfaces and reduces printing quality
Solution Approach 1:
The patent divides the scanning system into separate optical paths for different light beams, with each beam having its own dedicated scanning lens and focal point. The first light beam scans the first surface while the second light beam scans the second surface, and the optical elements are positioned and angled so that spray light from one beam does not interfere with the other beam's scanning path, enabling multi-surface scanning without cross-contamination
Solution Approach 2:
The patent utilizes angular positioning in the third dimension (vertical angle) to separate the optical paths. By adjusting the inclination angles of the scanning lenses and the positions of the light sources and polygon mirror faces, the system creates spatial separation between the spray light paths and the scanning paths, allowing multiple surfaces to be scanned simultaneously without spray light interference
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 reduces the impact of spray light, preventing the generation of poor quality printing such as stripes, while maintaining a simple structure with flexible lens shapes.
Implementation Method 1
a first light beam emitted by the first light source is reflected by the polygon mirror and passes through the first scanning lens and the third scanning lens
Implementation Method 2
first to fourth scanning lenses... a light beam emitted by each light source is substantially focused at each reference point of deflection
Data Source
AI summary
An optical scanning system comprising first and second light sources emitting first and second light beams, a polygon mirror and first to fourth scanning lenses, wherein when an x-axis is in a direction of the central axis of the polygon mirror, a y-axis is in a scanning direction, P1 and P2 respectively represent reference points of deflection of the first and second light beams, L1 and L2 respectively represent a distance between P1 and the first scanning lens and a distance between P2 and the second scanning lens, Lp12 represents a distance between P1 and P2, h1 and h2 respectively represent thicknesses of the first and second scanning lenses and each of θ1 and θ2 represent an acute angle between a projection of the principal ray each of the first and second light beams onto an x-y plane,h22.2≤(2·L1+L2+Lp12)·tanθ1h12.2≤(2·L2+L1+Lp12)·tanθ2are satisfied.