Exposure Apparatus Light Emitting Array Correction
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Solution Overview
Problem
Existing solid-state exposure methods for electrophotographic image-forming apparatuses face challenges in addressing local unevenness in light amount due to errors in rod lens arrays and light-emitting elements, which cannot be resolved by existing correction methods, leading to image deterioration when excessive pixel value corrections are made.
Innovation Solution
An exposure apparatus with a processor-controlled light-emitting element array that adjusts the number of active light-emitting elements based on correction data to correct local light amount unevenness, ensuring that correction amounts do not exceed a predetermined limit to avoid image deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pixel values are excessively corrected to eliminate local unevenness in light amount, then light amount uniformity is improved, but dot shape changes significantly resulting in image deterioration
Solution Approach 1:
The patent changes the parameter of correction amount from unlimited to limited by introducing a predetermined threshold. The correction amount is calculated based on light amount differences, but then constrained to not exceed the threshold value, thereby preventing excessive correction that would deform dot shapes while still achieving light amount uniformity within acceptable limits.
2Illumination intensity
If correction amount is increased to resolve local unevenness, then light amount uniformity is improved, but image quality deteriorates due to dot shape changes
Solution Approach 1:
The patent introduces a threshold parameter that limits the correction amount applied to pixel values. By constraining the correction amount to not exceed this predetermined threshold, the system achieves light amount uniformity while preventing image quality deterioration caused by excessive correction-induced dot shape changes.
3Illumination intensity
If more light-emitting elements are activated to compensate for local unevenness, then light amount uniformity is improved, but the complexity of control increases
Solution Approach 1:
The patent applies local quality by correcting pixel values on a per-pixel or per-region basis rather than uniformly across the entire image. The correction amount is calculated and applied locally to specific pixels or regions exhibiting light amount unevenness, allowing targeted correction without requiring complex global control mechanisms.
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 approach effectively reduces local light amount unevenness while maintaining image quality by limiting pixel value corrections, ensuring that dot shapes are preserved and image deterioration is avoided.
Implementation Method 1
a plurality of light-emitting elements that are arranged along a direction of a rotation axis of the photosensitive member and that emit light for exposing the photosensitive member
Implementation Method 2
The at least one processor is configured to control turning on and off of the plurality of light-emitting elements in accordance with the image data
Data Source
AI summary
An exposure apparatus includes light-emitting elements arranged along a direction of a rotation axis of a photosensitive member and at least one processor. The at least one processor is configured to controls driving of the light-emitting elements, generate correction data for use in increasing or decreasing the number of the light-emitting elements to be turned on based on a correction amount for correcting unevenness in light amount, and correct image data in accordance with a value indicated by the correction data. For a pixel for which the correction amount indicates a value exceeding a predetermined limit value, the correction data indicates a value that is equal to or smaller than the limit value.