Nozzle Correction Table for Print Color Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image processing technologies fail to effectively reduce color unevenness caused by individual variations in nozzle ejection characteristics when printing with multiple ink colors, leading to inaccurate color reproduction and perceived color differences in regions that should have the same coloring.
Innovation Solution
An image processing apparatus and method that involves converting input image data using conversion table parameters associated with nozzle positions, setting detection colors, generating and printing test images to identify color unevenness, and adjusting color correction patches to produce a conversion table that corrects for nozzle variations, ensuring uniform color output across print heads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If head shading technology is used to correct density unevenness, then the number of ink dots is adjusted for each nozzle to achieve uniform density, but color difference occurs in regions printed with multiple ink colors due to non-standard ejection volumes
Solution Approach 1:
The invention divides the correction process into separate stages: first correcting density unevenness using head shading, then separately correcting color accuracy by adjusting conversion table parameters for each nozzle position. This segmentation allows each correction to be optimized independently, resolving the contradiction between density uniformity and color accuracy.
Solution Approach 2:
The invention performs preliminary correction of density unevenness through head shading to establish uniform dot distribution, then applies subsequent correction using conversion table parameters to adjust color accuracy. This preliminary action ensures that the foundation of uniform density is established before fine-tuning color reproduction.
2Manufacturing precision
If head shading is applied to correct ejection volume variations, then density unevenness is reduced, but color unevenness persists in overlapping color regions due to variations in ejection direction
Solution Approach 1:
The invention separates the correction of density uniformity from color uniformity by using distinct correction mechanisms: head shading for density and conversion table parameter adjustment for color. This allows independent optimization of each aspect without interference.
Solution Approach 2:
The invention applies local quality correction by adjusting conversion table parameters specifically for each nozzle position that exhibits color unevenness, rather than applying a uniform correction across all nozzles. This targeted approach addresses local variations in ejection characteristics.
3Measurement precision
If conversion table parameters are adjusted for each nozzle position, then color unevenness is reduced, but the complexity of the image processing system increases
Solution Approach 1:
The invention performs preliminary measurement and analysis of nozzle ejection characteristics to establish conversion table parameters in advance. This preliminary action allows the complex parameter adjustment to be pre-computed, reducing the complexity during actual image processing operations.
Data Source
AI summary
Provided are an image processing apparatus and an image processing method capable of reducing color unevenness due to variations in ejection characteristics among a plurality of nozzles when printing an image using a plurality of inks. To that end, a first image which is made up a color with noticeable color unevenness and similar colors is printed onto a print medium. The user then specifies a color and a nozzle position where color unevenness has occurred. On the basis of these results, parameters are set for a correction table referenced by an MCS processor. In so doing, it becomes possible to address the factor causing the color unevenness, and mitigate the effects of color unevenness in a focused way without incurring increases in processor load, memory requirements, or processing time as compared to the case of calibrating all lattice points.