Interferential Pattern Calibration for Printer Printheads
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Solution Overview
Problem
Existing calibration methods for printing systems, such as ink-jet printers, face challenges in accurately aligning printheads and media transport systems due to mechanical misalignments and aliasing issues, especially when dealing with missing or malfunctioning nozzles, which affect the signal-to-noise ratio and require additional filtering.
Innovation Solution
The implementation of a specially-shaped interferential pattern that varies in amplitude along the printing axis, reducing aliasing effects and accommodating missing or malfunctioning nozzles, allowing for increased signal-to-noise ratio without additional filtering, and enabling precise calibration of printheads and media transport systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard line interferential pattern is used for calibration, then the calibration process can be performed, but aliasing issues occur and signal-to-noise ratio decreases requiring additional filtering
Solution Approach 1:
The patent modifies the interferential pattern by varying the amplitude of the waveform along the printing axis, creating a specially-shaped pattern that changes its characteristics in a specific direction. This parameter change eliminates aliasing effects while maintaining measurement precision for printhead alignment calibration
Solution Approach 2:
The patent employs a sinusoidal waveform pattern with varying amplitude that creates a curved, non-linear calibration pattern. This curved pattern approach naturally reduces aliasing compared to straight line patterns, improving the signal-to-noise ratio without requiring additional filtering
2Reliability
If conventional calibration patterns are used, then calibration can proceed, but missing or malfunctioning nozzles affect the signal-to-noise ratio and require additional filtering
Solution Approach 1:
By varying the amplitude of the interferential pattern along the printing axis, the patent creates a calibration pattern that is more robust to nozzle failures. The changing amplitude profile ensures that missing or malfunctioning nozzles do not create consistent noise patterns, improving reliability without requiring additional filtering steps
3Measurement precision
If standard calibration methods are used, then alignment can be calibrated, but printhead movement and mechanical misalignments cause inaccuracies
Solution Approach 1:
The sinusoidal interferential pattern with varying amplitude creates a distributed calibration reference across the printhead travel range. This curved pattern approach provides multiple reference points that compensate for mechanical misalignments and printhead movement, improving measurement precision despite mechanical instability
Data Source
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AI summary
Certain examples describe a method of calibrating a printer and a printing system. An interferential pattern is printed in the form of a print calibration image on a print medium. Data representative of the interferential pattern as printed on the print medium is detected using an optical sensor. The printer is calibrated based on the captured data. The interferential pattern is based on a waveform that varies in amplitude along an axis perpendicular to a printing axis under calibration and has repeated sets of multiple patterns based on the waveform, the repeated sets having a varying pattern spacing in the printing axis under calibration.