Concentric Fiducial Calibration Pattern for Printhead Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for generating alignment data for high-resolution pagewide printheads face challenges such as inadequate imaging resolution, rotational errors, noise susceptibility, and inefficiency in data generation, which affect print quality due to nozzle misalignments.
Innovation Solution
A method involving the printing of calibration patterns with concentric fiducials, cross-correlation analysis, and interpolation to generate accurate alignment data, using rotationally invariant concentric shapes and low-cross-correlation codes like the Barker code, to compensate for nozzle misalignments effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional line-based calibration patterns are used, then alignment data can be generated, but the measurement precision is insufficient due to rotational errors and noise susceptibility
Solution Approach 1:
The patent uses concentric circular patterns with asymmetric code sequences (e.g., Barker codes) arranged in specific sequences. The circular geometry provides rotational invariance while the asymmetric code patterns enable precise identification and measurement, allowing the system to achieve high measurement precision while being immune to rotational errors and noise interference.
Solution Approach 2:
The patent employs patterns printed with different ink colors or optical properties that can be distinguished by the imaging system. These color variations encode alignment information and enable the system to generate accurate alignment data even in the presence of noise, as the color-coded features provide robust detection signals.
2Measurement precision
If high-resolution imaging is used to capture calibration patterns, then alignment precision improves, but the device complexity and cost increase
Solution Approach 1:
The patent transitions from linear 1D calibration patterns to 2D concentric circular patterns with code sequences. This dimensional change allows the system to encode more alignment information in a compact space, enabling accurate alignment measurement using lower-resolution imaging systems while reducing device complexity and cost.
Solution Approach 2:
The calibration pattern is divided into multiple concentric circular rings, each containing code sequences that represent different alignment parameters. This segmentation allows the imaging system to capture and process alignment information at lower resolution, as each segment provides independent measurement data that contributes to the overall alignment accuracy.
3Reliability
If mechanical alignment methods are used, then permanent compensation is achieved, but adaptability to field conditions is reduced
Solution Approach 1:
The patent replaces mechanical alignment adjustment mechanisms with an optical/electronic system that uses concentric circular calibration patterns and image processing. This substitution enables the system to achieve reliable alignment compensation while maintaining full adaptability to field conditions, as the electronic alignment can be dynamically adjusted without mechanical intervention.
Solution Approach 2:
The calibration pattern is printed directly by the printing system itself, creating a self-calibrating mechanism. The system prints the concentric circular patterns, captures images of these patterns, and automatically generates alignment data without requiring external calibration tools or manual intervention, thereby achieving both reliability and field adaptability.
4Adaptability or versatility
If electronic alignment is used, then field adaptability improves, but alignment precision may be insufficient without high-resolution imaging
Solution Approach 1:
The patent uses 2D concentric circular patterns with code sequences that encode multiple alignment parameters. This dimensional enhancement allows electronic alignment to achieve high precision without requiring high-resolution imaging, as the pattern geometry and code sequences provide robust measurement signals that can be accurately detected at lower resolutions while maintaining field adaptability.
Data Source
AI summary
A print medium having a calibration pattern printed thereon for generating alignment data for a printhead. The calibration pattern contains rows of spaced apart fiducials, each fiducial having a plurality of concentric shapes representing a Barker code.