Weaving Masks for Printhead Nozzle Aerodynamic Interference
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Solution Overview
Problem
Page-wide printers with staggered printhead dies face image quality defects due to thermal ink jet winds causing nozzle redundancy issues, particularly in the stitching zones where different ink colorants interact, leading to visible artefacts like dark bands and deformed dots.
Innovation Solution
The implementation of complementary weaving masks applied to different rows of nozzles on the same die, allowing for controlled nozzle firing to mitigate the effects of thermal ink jet winds by separating the firing times of nozzles and maximizing the distance between drops, thereby reducing aerodynamic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nozzles in overlapping regions fire simultaneously, then printing speed is improved, but thermal ink jet winds cause aerodynamic interference leading to image quality defects
Solution Approach 1:
The patent applies periodic action by implementing a weaving mask that alternates nozzle firing in a systematic pattern across different rows and columns. This periodic firing sequence creates temporal separation between adjacent nozzle emissions, allowing drops to traverse the aerodynamic disturbance zone without causing thermal ink jet wind interference, thus maintaining image quality while preserving printing speed.
Solution Approach 2:
The patent employs preliminary action by pre-calculating and applying weaving masks that determine the firing sequence of nozzles before printing begins. The controller uses these pre-defined patterns to systematically stagger nozzle activation, ensuring that thermal ink jet winds from previously fired nozzles have dissipated before adjacent nozzles fire, thereby preventing aerodynamic interference while maintaining high-speed operation.
2Manufacturing precision
If nozzles in overlapping regions are used for redundancy, then placement errors can be corrected, but thermal ink jet winds cause visible artefacts like dark bands and deformed dots
Solution Approach 1:
The weaving mask implements periodic action by systematically alternating which redundant nozzles fire based on their position and the detected placement errors. This periodic firing pattern ensures that nozzles experiencing thermal ink jet wind interference are skipped in favor of alternative redundant nozzles, maintaining placement accuracy while avoiding the formation of visible artefacts.
Solution Approach 2:
The patent applies local quality by customizing the weaving mask pattern for specific overlapping regions based on their individual characteristics. Different regions may have different placement error profiles and thermal interference patterns, so the controller adjusts the firing sequence locally for each overlapping region, selecting which redundant nozzles to activate based on real-time conditions rather than using a uniform approach across all nozzles.
3Productivity
If multiple rows of nozzles fire simultaneously, then printing efficiency is maintained, but drops from different rows interact aerodynamically causing image quality defects
Solution Approach 1:
The weaving mask applies periodic action by implementing a systematic firing pattern that alternates between different rows of nozzles in a predetermined sequence. This periodic alternation ensures that drops from different rows are emitted at staggered intervals, allowing them to traverse the printing zone without aerodynamic interaction, thereby maintaining printing efficiency while eliminating image quality defects caused by drop interference.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively minimizes the impact of thermal ink jet winds on image quality, reducing artefacts in the stitching zones and enhancing the uniformity of the printed image, even in high-speed printing scenarios.
Implementation Method 1
thermal ink jet winds causing nozzle redundancy issues
Implementation Method 2
thermal ink jet winds causing nozzle redundancy issues, leading to visible artefacts
Data Source
AI summary
A printing apparatus comprises a printhead and a controller. The printhead includes dies, each die comprising rows of nozzles, wherein, in an overlapping region, the rows of nozzles of two dies overlap in a first direction, in which a relative movement between the printhead and a print medium takes place during operation of the printing apparatus. The controller is to apply a first weaving mask to a first row of nozzles of a first die and a second weaving mask to a second row of nozzles of the first die, the second weaving mask being different from the first weaving mask, the weaving masks defining, independent of print data, which of the nozzles of the corresponding row are to be used for printing in the overlapping region.