Image Processing Apparatus Density Correction via Adjacent Nozzle Shading
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Solution Overview
Problem
Conventional techniques for reducing density unevenness and streaks in inkjet printing, such as Head Shading and non-ejection complementation, are insufficient when only correcting defective nozzles, as they cannot achieve target densities, especially for nozzles with lower ejection amounts.
Innovation Solution
An image processing apparatus that corrects input images based on density characteristic information and target values, using adjacent nozzle adjustments to compensate for defective nozzles by shifting target characteristics and adjusting pixel values to ensure consistent output density across the print head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If correction is performed only for defective nozzles using conventional HS technique, then processing complexity is reduced, but density unevenness cannot be sufficiently corrected
Solution Approach 1:
The patent combines the HS technique and non-ejection complementation technique into a unified correction processing system. The correction processing unit integrates both correction methods and applies them together, merging the functionality of separate correction systems to achieve comprehensive density correction that neither method could achieve alone.
Solution Approach 2:
The patent segments the correction processing into distinct functional units: a correction processing unit that performs both HS and non-ejection complementation corrections, and a determination unit that identifies which nozzles require correction. This segmentation allows complex correction to be managed through modular processing stages.
2Manufacturing precision
If correction amount for defective nozzles is increased to achieve target density, then density uniformity is improved, but adjacent nozzles experience over-correction
Solution Approach 1:
The patent applies different correction strategies to different nozzle types: defective nozzles receive correction based on their specific ejection characteristics, while adjacent nozzles receive complementary correction only when needed. The determination unit identifies which nozzles require which type of correction, applying local quality adjustments rather than uniform correction across all nozzles.
Solution Approach 2:
The system uses determination units to assess whether correction is needed for each nozzle based on ejection amount characteristics. This feedback mechanism prevents over-correction by only applying corrections when actually needed, and the correction processing unit adjusts correction amounts based on this determination feedback.
3Manufacturing precision
If both HS technique and non-ejection complementation technique are used together, then correction comprehensiveness is improved, but processing complexity increases
Solution Approach 1:
The patent merges HS technique and non-ejection complementation technique into a single integrated correction processing unit. This unified structure manages both correction methods simultaneously, reducing the complexity that would arise from maintaining separate processing systems for each technique.
Solution Approach 2:
The correction processing unit is designed with multi-functionality, capable of performing both HS correction and non-ejection complementation correction through a single processing mechanism. This universal processor handles different correction types based on nozzle characteristics without requiring separate dedicated systems.
Data Source
AI summary
An object of the present disclosure is to reduce density unevenness and streaks of an image that is printed in a case where it is not possible to implement sufficient correction only by the correction for a defective nozzle. One embodiment of the present invention is an image processing apparatus that performs processing for an input image for an image forming apparatus performing printing on a printing medium by using a print head in which a plurality of printing elements is arrayed, the image processing apparatus including: a storage unit configured to store density characteristic information indicating an output density for each tone for each of the printing elements; a target value acquisition unit configured to acquire a target characteristic indicating a target value for each tone; and a first correction unit configured to correct the input image based on the density characteristic information and the target value.