Inkjet Image Processing for Non-Ejectable Nozzle Correction
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Solution Overview
Problem
Existing inkjet printing technologies face issues with density unevenness and white streaks due to nozzle variations and non-ejectable nozzles, leading to reduced productivity from frequent correction value calculations.
Innovation Solution
An image processing apparatus that detects non-ejectable nozzles and adjusts output tone values using density correction information, minimizing the influence of non-ejectable nozzles and their peripherals, thereby reducing density unevenness and white streaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If correction value calculation for density unevenness correction is performed frequently to maintain favorable printing results when non-ejectable nozzles occur, then printing quality is improved, but productivity is reduced due to time-consuming calculations
Solution Approach 1:
The patent pre-calculates and stores correction values for various nozzle failure scenarios in a lookup table before actual printing occurs. When a non-ejectable nozzle is detected, the system simply retrieves the pre-computed correction values from the table rather than performing time-consuming calculations during printing, thus maintaining high printing quality while preserving productivity
Solution Approach 2:
The patent creates a virtual model of the print head nozzle states and uses this model to pre-compute correction values for various failure scenarios. This virtual copying of the physical system allows the system to simulate and store correction strategies without affecting actual printing operations, enabling fast retrieval during real printing
2Manufacturing precision
If density correction processing and non-ejection complementation processing are performed in overlapping areas, then both density unevenness and white streaks are addressed, but excessive correction occurs causing black streaks and density unevenness
Solution Approach 1:
The patent applies different correction strategies to different spatial regions based on nozzle functionality. For areas affected by non-ejectable nozzles, non-ejection complementation is applied; for areas with density unevenness, density correction is applied; and for overlapping areas, the system selectively applies only one correction type based on pre-stored correction values, preventing excessive correction and black streak formation
Solution Approach 2:
The patent introduces a correction value lookup table as an intermediary that mediates between density correction and non-ejection complementation processes. This table stores pre-computed correction values that account for both types of issues, allowing the system to retrieve appropriate correction values without directly combining both correction processes and avoiding the harmful interaction that causes black streaks
Data Source
AI summary
An object is to enable highly accurate density unevenness correction while suppressing a reduction in productivity of printing accompanying correction value calculation for density unevenness correction. In the image processing apparatus, density correction information that specifies an output tone value for implementing a target density for an input tone value for each nozzle and which does not include the influence by a non-ejectable nozzle that cannot eject ink normally is acquired. In a case where a non-ejectable nozzle is detected during printing processing, output tone values corresponding to the detected non-ejectable nozzle and peripheral nozzles thereof among output tone values specified in the density correction information are changed.