Polygon Mirror Sync Signal Compensation for Image Quality
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Solution Overview
Problem
Conventional image forming apparatuses face deterioration in printing quality due to deviations in the reflective surfaces of the polygon mirror, which increases material costs when using multiple beam detectors or strict defectiveness criteria.
Innovation Solution
An image forming apparatus that includes a controller and a horizontal sync signal generator to calculate and compensate for deviations in the reflective surfaces of the polygon mirror by using beam detection signals and time offset counters, generating accurate horizontal sync signals for each reflective surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single beam detector is used to reduce material costs, then material cost decreases, but image quality deteriorates due to inability to compensate for polygon mirror reflective surface deviations
Solution Approach 1:
The patent segments the beam detection function by using a single beam detector to detect only one beam (e.g., from one light source) while using calculation to derive information about other beams. This segmentation allows reducing the number of physical beam detectors from multiple to one, thereby reducing material costs while maintaining image quality through computational compensation for polygon mirror deviations
Solution Approach 2:
The patent introduces an intermediary computational process (the controller calculating compensation values based on detected beam periods) that mediates between the single beam detector output and the required horizontal sync signals for multiple light sources. This intermediary calculation enables deriving information about undetected beams without requiring additional beam detectors, thus maintaining image quality while using fewer detectors
2Manufacturing precision
If multiple beam detectors are used to detect beams from each light source, then image quality is maintained, but material cost increases
Solution Approach 1:
The single beam detector is designed to perform multiple functions: detecting beams from one light source, providing timing information for horizontal sync signal generation, and enabling calculation of compensation values for all light sources. This multi-functionality allows one detector to replace multiple detectors, reducing material cost while maintaining image quality
Solution Approach 2:
The system uses the beam detection signal from a single detector to self-generate the necessary timing information for all light sources through computational processing. The controller calculates compensation values and generates horizontal sync signals autonomously based on the single detector's output, eliminating the need for additional detectors and reducing material costs
3Manufacturing precision
If strict defectiveness criteria are applied to polygon mirror manufacturing, then reflective surface deviation is reduced, but manufacturing cost increases
Solution Approach 1:
The patent implements a feedback mechanism where the beam detector detects actual beam periods, the controller calculates compensation values based on detected deviations, and the system adjusts horizontal sync signal generation accordingly. This feedback loop compensates for polygon mirror reflective surface deviations without requiring strict manufacturing criteria, thereby reducing manufacturing cost while maintaining image quality
Solution Approach 2:
The patent changes the approach from controlling physical manufacturing parameters (strict polygon mirror manufacturing tolerances) to controlling operational parameters (calculated compensation values and adjusted horizontal sync signals). By changing from physical precision control to computational parameter adjustment, the system maintains image quality while reducing manufacturing cost
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
Prevents image quality deterioration by accurately generating horizontal sync signals, reducing material costs and maintaining high printing quality without the need for multiple beam detectors.
Implementation Method 1
a beam detector which receives one beam that is output from one of the plurality of light sources and reflected from the polygon mirror
Data Source
AI summary
An image forming apparatus includes a plurality of photosensitive media, a light source unit which comprises a plurality of light sources, a polygon mirror which deflects a plurality of beams output from the plurality of light sources into the plurality of photosensitive media using a plurality of reflective surfaces, a beam detector which receives beams reflected from the polygon mirror during a rotating process of the polygon mirror, and outputs a beam detection signal, and a horizontal sync signal generator which receives the beam detection signal and counts beam reflecting times during which the beams are reflected from the plurality of reflective surfaces, and compares the plurality of counted beam reflecting times with the compensation values calculated for the reflective surfaces, respectively, generates a horizontal sync signal for a corresponding reflective surface, and provides the horizontal sync signal to the light source unit.