Print Head Misregistration Detection Using Test Pattern Analysis
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Solution Overview
Problem
Conventional image printing apparatuses require high-resolution line sensors and precise optical system adjustments to detect minute positional shifts of print heads, making the process complex and inaccurate.
Innovation Solution
An information processing device and method that uses a test image with specific line patterns and reference marks to calculate positional shifts between print heads, allowing for easy and accurate detection of print head misalignment without relying on high-resolution sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-resolution line sensor is used to detect minute positional shifts of print heads, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates a virtual copy of the print head position information by printing test patterns and capturing them with a standard line sensor. Instead of using a high-resolution sensor to directly measure position, the system captures an image of the printed test pattern and processes it computationally to determine positional shifts, thereby achieving high measurement precision with a standard sensor.
Solution Approach 2:
The patent replaces the direct optical measurement approach (mechanical/optical system) with an image processing approach. Instead of relying on the line sensor's optical resolution to detect minute shifts, the system uses software algorithms to analyze the captured test pattern images and calculate positional deviations, substituting computational processing for hardware precision requirements.
2Measurement precision
If high-precision calibration of the optical system and line sensor arrangement is performed, then measurement precision is improved, but ease of manufacture and operation deteriorate
Solution Approach 1:
The system performs self-calibration by automatically capturing test patterns, processing the images, and calculating correction values without requiring manual intervention for precise optical alignment. The calibration process is automated and does not demand high skill levels or complex manual adjustment procedures.
Solution Approach 2:
The patent changes the approach from adjusting physical parameters (optical system alignment, sensor positioning) to modifying computational parameters (image processing algorithms, coordinate transformation matrices). This allows calibration to be performed through software rather than precise mechanical adjustment, greatly simplifying the manufacturing and operation processes.
3Measurement precision
If conventional line sensor methods are used for positional shift detection, then measurement precision can be achieved, but ease of operation deteriorates due to complex calibration requirements
Solution Approach 1:
The system performs preliminary calibration by automatically capturing test patterns and computing correction values before actual printing operations. This preliminary action establishes the baseline position information and correction matrices, eliminating the need for complex manual calibration during operation and making the system easy to use.
Solution Approach 2:
The patent replaces manual optical calibration operations with automated image processing. The system uses software to analyze captured test patterns and compute positional corrections, substituting computational methods for manual mechanical adjustment procedures, thereby greatly simplifying operation while maintaining high measurement precision.
Data Source
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AI summary
Provided are an information processing device, an image printing apparatus and an information processing method with which it is possible to detect print head misregistration easily and with high precision. On the basis of imaging data for a test image comprising multiple first lines and multiple second lines respectively printed by first and second printing means, the information processing device specifies the relative positional relationship between first and second coordinate axes from the corresponding relationship between: first line printing coordinates on the first coordinate axis for which a first unit coordinate interval has been prescribed and second line printing coordinates, for which a second unit coordinate interval has been prescribed and which relate to the second coordinate axis for which a reference position, when the first printing means and the second printing means are disposed in a specified positional relationship, assumes a prescribed relative reference position relationship to a reference position of the first coordinate axis; and the first and second line printing positions in the imaging data. On the basis of said relative positional relationship and the prescribed relative reference position relationship, the information processing device calculates a value corresponding to the magnitude of misregistration of the second printing means from the specified positional relationship with respect to the first printing means.