Coil Impedance Screening for Foreign Matter in Banknote Feed Paths

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Solution Overview

Problem

Banknote processing apparatuses misrecognize banknotes with metal components as foreign objects, leading to reduced detection accuracy of foreign object inclusion.

Innovation Solution

A sheet processing apparatus with a coil in the feeding unit generates a magnetic field, using either a first or second evaluation criterion based on impedance to determine the presence of foreign objects, improving detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a metal detection apparatus uses a coil to detect foreign objects in banknotes, then foreign object detection capability is improved, but banknotes with metal components (holograms, metal threads) are misrecognized as foreign objects, reducing detection accuracy

Engineering Contradiction:
Improveforeign object detection accuracyVSAvoiddetection accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system changes the evaluation parameters by using multiple different evaluation criteria (first, second, and third evaluation criteria) that assess different aspects of the impedance signal. Each criterion evaluates different characteristics of the detected signal, allowing the system to distinguish between genuine foreign objects and legitimate metal components in banknotes by analyzing the signal from multiple perspectives.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system dynamically selects which evaluation criterion to apply based on the detected impedance characteristics. The control unit adaptively chooses the most appropriate evaluation criterion depending on the situation, making the detection system flexible and context-aware rather than relying on a single static detection threshold.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the detection system uses a single evaluation criterion based on impedance, then the detection process is simple, but it cannot accurately distinguish between foreign objects and metal components in banknotes

Engineering Contradiction:
Improvedetection system simplicityVSAvoidforeign object detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system dynamically selects which evaluation criterion to apply based on the detected impedance characteristics. The control unit adaptively chooses the most appropriate evaluation criterion depending on the situation, making the detection system flexible and context-aware rather than relying on a single static detection threshold.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the evaluation parameters by using multiple different evaluation criteria (first, second, and third evaluation criteria) that assess different aspects of the impedance signal. Each criterion evaluates different characteristics of the detected signal, allowing the system to distinguish between genuine foreign objects and legitimate metal components in banknotes by analyzing the signal from multiple perspectives.

Inventive Principle:
Principle #35Parameter changes

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

Enhances the detection accuracy of foreign objects in banknote processing by accurately distinguishing between metal components and genuine banknotes.

Implementation Method 1

a coil that is disposed in a feeding unit and produces a magnetic field

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

evaluates a value based on an impedance of the coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4012398B1Paper sheet handling device and foreign matter detection method
Publication Date: 2026.02.25 GLORY LTD
  • EP4012398B1 patent drawingFigure 1
  • EP4012398B1 patent drawingFigure 2~3
  • EP4012398B1 patent drawingFigure 4

AI summary

A paper sheet handling device according to the present invention has: a coil that is provided to a delivery unit for delivering fed paper sheets to a conveyance path and that generates a magnetic field; and a control unit that evaluates a value based on an impedance of the coil by selecting one of a first evaluation criterion and a second evaluation criterion and that determines the presence/absence of foreign matter in the delivery unit on the basis of the evaluation result.