Magnetic Sensor Sensitivity Correction for Sheet Inspection
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Solution Overview
Problem
Existing magnetic inspection devices face challenges in quickly and precisely adjusting the sensitivity of multiple magnetic sensing portions to accurately detect magnetic characteristics of sheets, requiring stabilization of magnetic field lines and correction for uneven sensitivity.
Innovation Solution
A magnetic sensor configuration with a permanent magnet and a conductor generating a bias magnetic field and a pulse-like current, respectively, to stabilize and adjust the magnetic field distribution, allowing for simultaneous sensitivity adjustment of multiple sensing portions and precise detection of magnetic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple magnetic sensing portions are arranged to detect the entire sheet area, then detection precision is improved, but sensitivity unevenness occurs across different sensing portions
Solution Approach 1:
The patent applies local quality by providing individual sensitivity correction for each magnetic sensing portion through separate correction coefficients. Each sensing portion's output is corrected based on its specific characteristics, allowing precise detection across the entire sheet area while compensating for local sensitivity variations.
2Measurement precision
If sensitivity correction is performed for each magnetic sensing portion individually, then sensitivity precision is improved, but adjustment time increases
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing correction coefficients for each magnetic sensing portion before actual sheet detection begins. These coefficients are determined in advance through calibration processes, allowing rapid sensitivity correction during operation without time-consuming individual adjustments for each sensing portion.
3Measurement precision
If a stable magnetic field is generated for sensitivity correction, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by using the sheet itself as the magnetic field source during sensitivity correction. The sheet's own magnetic properties generate the necessary magnetic field, eliminating the need for external magnetic field generation devices and simplifying the overall system while maintaining measurement precision.
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 configuration enables rapid and precise correction of sensitivity unevenness, stable generation of magnetic field changes, and efficient detection of magnetic characteristics without requiring additional magnetic print density management or object presence for self-diagnosis, while minimizing cost and environmental interference.
Implementation Method 1
a permanent magnet and a conductor generating a bias magnetic field and a pulse-like current, respectively, to stabilize and adjust the magnetic field distribution
Implementation Method 2
a permanent magnet and a conductor generating a bias magnetic field and a pulse-like current, respectively, to stabilize and adjust the magnetic field distribution
Implementation Method 3
apparatuses that detect magnetic characteristic information of sheets that are being conveyed, using a magnetic sensor
Data Source
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AI summary
According to one embodiment, a magnetic sensor includes: a case (11) disposed facing an object (P) that is to be detected; a plurality of magnetic sensing portions (12) accommodated inside the case (11); and a magnetic generator (14) disposed inside the case (11), between the plurality of magnetic sensing portions (12) and the object (P) that is to be detected.