Magnetic Sensor Head Noise Correction for Sheet Detection

Solution Overview

Problem

Magnetic detecting devices in sheet processing apparatuses face challenges in precisely detecting magnetic properties of sheets due to magnetic noise generated by electrical devices, which interferes with the detection of authentic magnetic properties.

Innovation Solution

A magnetic detecting device with a magnetic sensor head comprising multiple magnetic sensing units arranged in a line, both inside and outside the sheet passage area, utilizing semiconductor magneto-resistive elements and a compensation signal generating unit to differentiate and correct for environmental magnetic noise, allowing precise detection of sheet magnetic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetic sensing units are installed in sheet processing apparatus to detect magnetic properties of sheets, then the ability to read magnetic properties is improved, but magnetic noise from electrical devices interferes with detection precision

Engineering Contradiction:

Improvedetection precision of magnetic propertiesVSAvoidmagnetic noise from electrical devices

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The magnetic sensor head is divided into multiple magnetic sensing units arranged in a line, with specific units positioned inside and outside the sheet passage area. This segmentation allows the system to distinguish between magnetic signals from sheets and magnetic noise from the environment by comparing readings from different sensor positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A compensation signal generating unit is introduced as an intermediary component that processes signals from the magnetic sensing units. This unit generates compensation signals based on readings from sensors outside the sheet passage area and subtracts these compensation signals from readings of sensors inside the passage area, effectively eliminating magnetic noise interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If multiple magnetic sensing units are arranged both inside and outside the sheet passage area, then environmental magnetic noise can be differentiated and corrected, but device complexity increases

Engineering Contradiction:

Improveprecision of magnetic property detectionVSAvoidcomplexity of sensor arrangement and signal processing

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The magnetic sensor head is divided into multiple magnetic sensing units arranged in a line, with specific units positioned inside and outside the sheet passage area. This segmentation allows the system to distinguish between magnetic signals from sheets and magnetic noise from the environment by comparing readings from different sensor positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A compensation signal generating unit is introduced as an intermediary component that processes signals from the magnetic sensing units. This unit generates compensation signals based on readings from sensors outside the sheet passage area and subtracts these compensation signals from readings of sensors inside the passage area, effectively eliminating magnetic noise interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The device can accurately specify the magnetic properties of sheets by isolating and subtracting environmental magnetic noise, enhancing the precision of authenticity determination in sheet processing apparatuses.

Implementation Method 1

utilizing semiconductor magneto-resistive elements

Methodology Applied

Scientific EffectMagneto-resistive effect: Magnetoresistance

Data Source

PatentEP3032252B2Magnetic detection device and paper sheet processing device

Publication Date: 2020.07.22 KK TOSHIBA

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AI summary

A magnetic detecting device according to an embodiment includes: a magnetic sensor head in which a plurality of magnetic sensing units including a first magnetic sensing unit and a second magnetic sensing unit are arranged; and an environmental magnetism correcting unit. The plurality of magnetic sensing units is arranged in one line over a length that is greater than a width of a sheet, in a direction that is orthogonal to a movement direction of the sheet. The environmental magnetism correcting unit corrects a first output signal output by the first magnetic sensing unit, based on a second output signal output by the second magnetic sensing unit. The magnetic sensor head has a sheet passage area that faces a sheet that passes over the magnetic sensor head, the first magnetic sensing unit is positioned inside the sheet passage area, and the second magnetic sensing unit is positioned outside the sheet passage area.