Non-magnetic Roller Surface for Magnetic Detection Accuracy
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Solution Overview
Problem
Conventional banknote handling apparatuses face degradation in magnetism detection accuracy due to magnetization of transport rollers caused by magnetic metal objects, leading to noise interference, especially when using magnetic metal bearings for cost and durability considerations.
Innovation Solution
A paper sheet magnetic detection apparatus with transport rollers having outer peripheral surfaces made of non-magnetic materials to prevent magnetization, allowing the use of magnetic metal bearings for durability while maintaining detection accuracy by isolating the magnetic sensor's bias field from the rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transport roller made of magnetic metal is used, then durability is improved, but the roller gets magnetized by the magnetic sensor's bias field causing noise and degrading detection accuracy
Solution Approach 1:
The transport roller is constructed as a composite structure with a magnetic metal core (providing durability) and a non-magnetic outer peripheral surface layer (providing resistance to magnetization). This composite design allows the roller to maintain high durability while preventing the bias magnetic field from magnetizing the roller, thereby eliminating noise in magnetic detection.
2Measurement precision
If a non-magnetic metal roller is used, then magnetization is prevented, but the durability of the roller becomes low
Solution Approach 1:
The roller combines magnetic metal core (for durability) with non-magnetic outer surface layer (for preventing magnetization), achieving both high durability and resistance to magnetization simultaneously.
3Volume of moving object
If the magnet and transport roller are arranged close to each other for downsizing, then apparatus size is reduced, but the roller is more easily magnetized by the bias field
Solution Approach 1:
The non-magnetic outer peripheral surface layer on the transport roller prevents magnetization even when the roller is positioned close to the magnet, enabling apparatus downsizing without compromising detection accuracy.
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
Prevents magnetization of transport rollers, ensuring accurate magnetism detection and enabling downsizing of the apparatus by using non-magnetic outer layers on rollers, reducing noise interference and maintaining high durability with cost-effective magnetic metal bearings.
Implementation Method 1
Magnetic material, such as a magnetic ink or a magnetic thread, incorporated in a paper sheet is detected based on a magnetic flux change as the magnetic material passes through the bias magnetic field.
Implementation Method 2
Outer peripheral surfaces of the plurality of transport rollers that face the transport path are made of a non-magnetic material
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
The object is to avoid degradation of magnetic detection precision arising due to magnetization of transport rollers used for transporting a paper sheet. A paper sheet magnetic detection apparatus that detects a magnetic material in the paper sheet by using a magnetic sensor includes a transport path that transports paper sheets one by one; at least one magnet that is used in the detection of the magnetic material by the magnetic sensor; and a plurality of transport rollers that are arranged near the magnetic sensor and that transport the paper sheet in the transport path. Outer peripheral surfaces of the plurality of transport rollers that face the transport path are made of a nonmagnetic material.