Inkjet Nozzle-Group Control for Curved Spectacle Lens Printing
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Solution Overview
Problem
Inkjet printing technologies face challenges in achieving consistent printing quality on spectacle lenses with higher curvature due to the mismatch between flat printheads and non-planar lens surfaces, leading to degraded printing quality towards the edges.
Innovation Solution
A computer-implemented method for determining individual printing parameter values for each nozzle group, optimizing the printing process by considering geometric relationships and environmental conditions, allowing for improved printing quality on curved surfaces without requiring complex hardware adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If flat printheads are used for inkjet printing, then printing process simplicity is maintained, but printing quality degrades on curved spectacle lens surfaces
Solution Approach 1:
The patent applies local quality by dividing the printhead into multiple nozzle groups (e.g., 3-5 groups) along the scanning direction, with each group having independently optimized printing parameters. This allows different regions of the printhead to compensate for varying distances to the curved lens surface, maintaining consistent droplet deposition quality across the entire lens while keeping the overall system simple.
Solution Approach 2:
The patent changes printing parameters (voltage, jetting frequency, waveform) locally for different nozzle groups based on their position relative to the curved lens surface. By optimizing parameters for each nozzle group according to its specific geometric relationship with the lens, the system achieves uniform printing quality across curved surfaces without modifying the flat printhead structure itself.
2Manufacturing precision
If individually optimized printing parameters are applied to each nozzle group, then printing quality on curved surfaces is improved, but device complexity increases
Solution Approach 1:
The patent segments the printhead into multiple nozzle groups along the scanning direction, with each group controlled by independently optimized printing parameters. This segmentation allows localized parameter optimization for different regions of the printhead, compensating for varying distances to the curved lens surface while maintaining manageable system complexity through modular parameter control.
Solution Approach 2:
The patent performs preliminary optimization of printing parameters for each nozzle group before the actual printing process. By pre-calculating and storing optimized parameter sets for different nozzle groups based on the lens curvature and printhead geometry, the system eliminates the need for real-time parameter adjustments during printing, reducing operational complexity while maintaining high printing quality.
3Manufacturing precision
If multiple printing passes are used to achieve uniform quality, then printing quality consistency is improved, but productivity decreases
Solution Approach 1:
The patent implements local quality optimization by assigning different printing parameters to different nozzle groups based on their position along the scanning direction. This allows all nozzle groups to deposit droplets with consistent quality in a single printing pass, eliminating the need for multiple corrective passes and thereby maintaining high productivity while achieving uniform printing quality across the entire lens surface.
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
Enhances printing quality on curved spectacle lens surfaces by optimizing printing parameters, enabling high-quality printing in a single pass and reducing the need for complex hardware arrangements, thus expanding the applicability of inkjet technology in spectacle lens production.
Implementation Method 1
nozzles are filled with and emptied off (=jetting of droplets) ink by making use of shockwaves stemming from piezoelectric actuation
Data Source
AI summary
A computer-implemented method for determining printing parameter values of an inkjet printing device for printing a pattern on a surface of a spectacle lens substrate is provided. The inkjet printing device includes a printhead with a plurality of printing nozzles. The method includes: grouping the plurality of printing nozzles into at least two printing nozzle groups, and individually determining a printing parameter value for at least one adjustable printing parameter of each printing nozzle group. In addition, a data processing system, a computer program, a non-transitory computer-readable storage medium, a method for inkjet printing, an inkjet printing device, and a spectacle lens substrate with a pattern printed on a surface of the spectacle lens substrate are provided.