Bidirectional Printer Color Correction Lookup Tables
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Solution Overview
Problem
Existing bidirectional printing technologies face challenges in minimizing color differences between outbound and return passes due to changes in paper type and other printing conditions, as previous solutions do not adequately address adjustments to lookup tables or color conversion processes.
Innovation Solution
A printing system that includes a print unit and an adjustment unit capable of generating and using different color conversion information for each print medium, allowing for the adjustment of color conversion tables based on specific coefficients to minimize color differences between outbound and return passes, regardless of paper type or other printing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bidirectional printing is implemented to increase printing speed, then productivity is improved, but color difference between outbound and return passes increases
Solution Approach 1:
The patent applies parameter changes by adjusting the ink ejection amount based on the printing direction. Specifically, when printing in the return direction, the ink ejection amount is modified using a direction-dependent correction value stored in a lookup table, allowing the system to compensate for color differences while maintaining high-speed bidirectional printing
Solution Approach 2:
The patent implements local quality by applying different color conversion parameters for outbound and return passes. A direction-specific correction value is selected from a lookup table based on the current printing direction, enabling localized adjustment of ink ejection characteristics to match the substrate's absorption properties in each direction
2Manufacturing precision
If color conversion tables are adjusted for different paper types to reduce color difference, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing direction-dependent correction values in a lookup table during system initialization or calibration. These correction values are prepared in advance for different printing directions and paper types, eliminating the need for complex real-time calculations during actual printing operations
Solution Approach 2:
The patent uses copying by creating a direction-specific color conversion table that mirrors the standard conversion table but includes additional direction-dependent correction factors. This copied table structure allows the system to reuse existing color management infrastructure while adding directional compensation capabilities
3Manufacturing precision
If multiple lookup tables are used for outbound and return passes to minimize color difference, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the color conversion functionality by integrating direction-dependent correction into a unified lookup table structure. Instead of maintaining completely separate color conversion tables for outbound and return passes, the system uses a single table that incorporates direction identifiers, allowing both conversion paths to be managed through one centralized data structure
Solution Approach 2:
The patent applies universality by designing a multi-functional lookup table that serves both outbound and return pass color conversion needs. The same lookup table structure is used for both printing directions, with direction-specific entries selected based on the current pass, reducing the need for multiple specialized tables
Data Source
AI summary
A printer has a print unit that prints bidirectionally on a print medium; and an adjustment unit that prints, by the print unit, in contrast with each other on a second print medium, a first direction print image generated using first direction color conversion information for a first print medium, and a second direction print image generated using second direction color conversion information for a second print medium; the second direction color conversion information for the second print medium being second direction color conversion information for the first print medium that was adjusted.