Density Correction Table Selection for Image Uniformity
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Solution Overview
Problem
Conventional image forming apparatuses struggle to accurately correct density nonuniformity in the main-scanning direction of images, especially when layout changes occur after density correction, as existing methods only correct within a limited density range and fail to appropriately adjust density tables for sub-scanning direction changes.
Innovation Solution
An image forming apparatus with a storage unit for multiple density correction tables corresponding to positions in the main-scanning direction, an input unit for image data, a determination unit to select the appropriate density correction table based on print settings, and a correction unit to adjust pixel densities using the determined table, ensuring accurate density correction across the entire density range even after layout changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single density correction table is applied to image data, then density nonuniformity in the main-scanning direction can be corrected for a specific density range, but density nonuniformity cannot be corrected across the entire density range when layout processing is performed
Solution Approach 1:
The patent divides the density correction function into multiple density correction tables, each corresponding to a specific position in the main-scanning direction. This segmentation allows the system to handle different density characteristics at different positions independently, enabling accurate correction across the entire density range even when layout processing is applied.
Solution Approach 2:
The patent implements dynamic selection of density correction tables based on print settings and pixel positions. The determination unit dynamically determines which density correction table to apply by considering the pixel's position in the main-scanning direction and the current print settings, allowing the system to adapt to various layout configurations while maintaining correction accuracy.
2Manufacturing precision
If density correction is performed before layout processing, then density nonuniformity can be corrected initially, but the correction becomes inappropriate after rotation or position adjustment
Solution Approach 1:
The patent prepares multiple density correction tables in advance, each corresponding to different positions in the main-scanning direction. This preliminary preparation allows the system to quickly select and apply the appropriate correction table after layout processing, maintaining both density uniformity and layout flexibility without requiring re-correction after each layout change.
Solution Approach 2:
The patent changes the parameter selection criteria for density correction from fixed position-based selection to dynamic selection based on pixel position in the main-scanning direction combined with print settings. This parameter change enables the system to maintain appropriate density correction regardless of layout transformations.
3Device complexity
If conventional density correction methods are used, then processing is simple, but correction accuracy is limited to certain density ranges
Solution Approach 1:
The patent segments the density correction function into multiple tables covering different density ranges and positions in the main-scanning direction. This segmentation extends the correction range across the entire density spectrum while maintaining relative system simplicity through organized table storage and efficient selection mechanisms.
Data Source
AI summary
An image forming apparatus receives a print setting for image data, determines a density correction table to be applied to a position of a pixel in the image data based on the received print setting from among a plurality of stored density correction tables, and corrects a density of the image data using the determined density correction table.