Optical Scanning Device Asymmetric Rotational Adjustment
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Solution Overview
Problem
High-resolution optical scanning devices face resolution deterioration due to increased sub-scanning width when a multi-beam light source is rotationally adjusted, particularly at higher resolutions like 2400 dpi, leading to larger dot diameters and conspicuous deviations in beam alignment.
Innovation Solution
The multi-beam light source is rotationally adjusted differently depending on the incidence side (one-side or other-side incidence) to minimize the sub-scanning width by adjusting the rotational direction around the rotational axis, ensuring that light beams from both ends of the light emitting elements have more aligned optical paths, thereby reducing the deviation from the targeted position on the rotary polygon mirror.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the multi-beam light source is rotationally adjusted to align beams, then beam alignment improves, but the sub-scanning width increases causing resolution deterioration
Solution Approach 1:
The patent applies asymmetry by setting different rotational adjustment directions for the multi-beam light source depending on which side the light beams are incident. When light beams are incident from the lower side, the light source is rotated in one direction, and when incident from the upper side, it is rotated in the opposite direction. This asymmetric adjustment strategy minimizes the sub-scanning width while maintaining beam alignment precision, thereby resolving the contradiction between alignment precision and resolution.
2Manufacturing precision
If high resolution scanning is performed, then image quality improves, but the sub-scanning width becomes more critical and causes more noticeable resolution deterioration
Solution Approach 1:
The patent implements preliminary anti-action by pre-adjusting the rotational direction of the multi-beam light source based on the incidence side before performing high-resolution scanning. This preventive measure counteracts the potential increase in sub-scanning width that would otherwise occur during high-resolution operation, thereby eliminating the harmful effect on resolution before it manifests.
3Measurement precision
If the multi-beam light source is adjusted for one incidence side, then alignment is optimized for that side, but performance deteriorates when switching to the other incidence side
Solution Approach 1:
The patent applies dynamics by making the rotational adjustment direction of the multi-beam light source variable rather than fixed. The system dynamically adapts the rotation direction based on which incidence side is being used, allowing optimal alignment precision to be maintained regardless of whether light beams are incident from the upper or lower side. This dynamic adjustment strategy ensures both alignment precision and adaptability to different incidence configurations.
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 adjustment technique effectively reduces the sub-scanning width, thereby suppressing resolution deterioration and maintaining high image quality even at high resolutions by ensuring more precise beam alignment and reduced dot diameter.
Implementation Method 1
a plurality of light beams emitted from each of the plurality of light emitting elements are reflected by the reflection mirror, the plurality of light beams reflected by the reflection mirror are made incident to the rotary polygon mirror, and the plurality of light beams reflected by the rotary polygon mirror are emitted toward an object to be scanned
Data Source
AI summary
A rotational direction of a multi-beam light source around a rotational axis is made different to a side where a sub-scanning width in a sub-scanning direction of a plurality of light beams is made smaller between a case of one-side incidence in which the plurality of light beams are made incident to the rotary polygon mirror from either one of sides in the rotary axis direction of a rotary polygon mirror and a case of the other-side incidence in which the plurality of light beams are made incident to the rotary polygon mirror from the other side.