Complementary Mask Patterns for Multi-Pass Inkjet Printing
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Solution Overview
Problem
Inkjet printing systems using multiple nozzle arrays face issues with print position errors between nozzle arrays, leading to unevenness in images, even when employing multi-pass printing and column thinning techniques.
Innovation Solution
An image processing method that generates ejection data using complementary mask patterns for alternating nozzle arrays, ensuring that each nozzle array prints complementary regions, thereby maintaining image uniformity despite print position errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple nozzle arrays are used for multi-pass printing with column thinning, then productivity is improved by reducing printing time, but print position errors between nozzle arrays cause image uniformity to deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-defining complementary mask patterns for different nozzle arrays before printing. These mask patterns are designed in advance to ensure that even if print position errors occur, the complementary regions will compensate for each other. The mask patterns are prepared beforehand with the understanding that they need to cover complementary areas to maintain image uniformity despite positional variations.
Solution Approach 2:
The patent changes the parameter of mask pattern design by making them complementary rather than identical. Different nozzle arrays are assigned different complementary mask patterns that cover different regions. This parameter change allows the system to tolerate print position errors because the complementary nature of the masks ensures that gaps in one array's coverage are filled by another array's coverage.
2Manufacturing precision
If complementary mask patterns are used for different nozzle arrays, then image uniformity is maintained despite print position errors, but device complexity increases due to multiple mask pattern management
Solution Approach 1:
The patent applies local quality by assigning different mask patterns to different nozzle arrays based on their local characteristics and positions. Each nozzle array has a tailored mask pattern that is optimized for its specific role in the multi-pass printing process. This local differentiation allows the system to maintain image uniformity while managing complexity through a systematic approach to pattern assignment.
Data Source
AI summary
For a multi-pass printing, an image of a unit area is printed by M printing scans of M print regions of first and second nozzle arrays. Each of N pieces of column data is printed by a different printing scan. Ejection data for the first nozzle array is generated using a first mask pattern and ejection data for the second nozzle array is generated using a second mask pattern different from the first mask pattern, for each of the N pieces of column data. On that basis, the first mask pattern and the second mask pattern have a complementary relationship in each of the M print regions. Further, in each of the first mask pattern and the second mask pattern, a combination of print regions, of the M print regions, for printing dots at the same position on the print medium has a mutually complementary relationship.