Inkjet Print Data Processing for Ejection Failure Compensation
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Solution Overview
Problem
Conventional image printing methods face challenges in maintaining image quality when ejection failures occur in inkjet printing, particularly in cases where multiple-bit information is used, as they struggle to perform effective complement printing, especially when ejection failures involve multiple ejection ports or when no information is available for zero-time ink permission in mask patterns.
Innovation Solution
An image processing apparatus generates print data using a printing head with multiple ejection ports, acquiring image data with information on ink ejection times from zero to N times and mask patterns with permission information from 0 to M times for each pixel, and performs non-ejection complementary processing by replacing code values to ensure optimal ink ejection even when ejection failures occur, by selecting and replacing code values to maintain the ideal number of ink ejections across multiple scanning passes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple-bit information is used for determining ink ejection times, then image quality can be improved through multiple ejections to one pixel region, but complement printing becomes difficult when ejection failures occur in multiple ejection ports
Solution Approach 1:
The system performs preliminary classification of ejection ports into first ejection ports (with available complement information) and second ejection ports (without available complement information) before printing. This advance classification enables the system to prepare appropriate mask patterns for each group, ensuring that complement printing can be executed effectively even when multiple ejection ports fail, thereby maintaining both image quality and reliability
Solution Approach 2:
The mask patterns are divided into multiple types corresponding to different ejection ports and scanning passes. By segmenting the complement information into distinct mask patterns for first and second ejection ports, the system can selectively apply appropriate compensation strategies for each group, resolving the contradiction between maintaining image quality through multiple ejections and ensuring complement printing capability
2Area of stationary object
If mask pattern permits ejection for all pixels in small scan mode, then printing coverage is improved, but complement printing cannot be performed when ejection failure occurs
Solution Approach 1:
The system applies different mask pattern strategies to different ejection port groups based on their local characteristics. For first ejection ports, one type of mask pattern is used that allows complement printing, while for second ejection ports, another type is used. This local differentiation enables the system to maintain both comprehensive printing coverage and complement printing capability for each specific ejection port group
3Productivity
If ejection failure occurs in multiple ejection ports, then printing can continue with remaining ports, but sufficient complement information cannot be found for all failed ports
Solution Approach 1:
The system creates multiple types of mask patterns that can serve different functions depending on which ejection ports are operational. Each mask pattern type is designed to work with specific groups of ejection ports, allowing the system to universally handle various failure scenarios. This multi-functionality ensures that complement information is available regardless of which specific ports fail, maintaining both printing continuity and information availability
Data Source
AI summary
Replacement processing is executed when the number of times of permission for a pixel corresponding to an ejection defective nozzle in a mask pattern is larger than a smallest number of times of permission, of the numbers of times of permission for pixels corresponding to ejection normal nozzles.