Ultrasonic Multi-feed Detection Circuit Stabilization
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Solution Overview
Problem
Existing multi-feed detection mechanisms in medium processing apparatuses, such as printers and scanners, face inaccuracies due to amplifier oscillation states during medium transport pauses, leading to determination errors caused by unstable sensor signals.
Innovation Solution
Incorporating an ultrasonic oscillator, sensor, amplification circuit, integration circuit, and discharge circuit that stabilize the signal by predicting and managing oscillation states through controlled discharge periods, ensuring accurate multi-feed determination by evaluating output convergence and terminating oscillation states before making determinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amplification circuit amplifies the sensor signal several tens of thousands times, then the sensor signal output is sufficiently amplified for detection, but the amplification circuit may shift to an oscillation state causing determination errors
Solution Approach 1:
The discharge circuit performs preliminary discharge of the integration capacitor before multi-feed determination to eliminate residual charges that could cause oscillation. By discharging the capacitor in advance and waiting for a predetermined period, the system ensures the amplification circuit is in a stable state before measurement, preventing oscillation-induced determination errors while maintaining high signal amplification capability.
2Productivity
If multi-feed determination is performed quickly during medium transport, then productivity is improved, but determination accuracy deteriorates due to unstable phenomena during medium transport pause
Solution Approach 1:
The system performs preliminary discharge and stabilization before the actual determination process. By discharging the integration capacitor and waiting for a predetermined period to ensure circuit stability, the system eliminates unstable phenomena that occur during medium transport pause. This preliminary preparation enables accurate determination without sacrificing productivity, as the stabilization period is minimized while still ensuring reliability.
3Reliability
If the discharge circuit discharges the integration capacitor continuously, then oscillation states are prevented, but the circuit cannot perform accurate multi-feed determination
Solution Approach 1:
The discharge circuit operates periodically rather than continuously. It discharges the integration capacitor at specific intervals (before multi-feed determination and before medium ejection) to eliminate oscillation states, then stops discharging to allow proper signal integration and determination. This periodic discharge strategy maintains circuit stability while preserving the ability to perform accurate multi-feed determination during non-discharge periods.
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 achieves stable and quick multi-feed determination by avoiding accuracy deterioration from unstable phenomena during medium transport pauses, enhancing the reliability of multi-feed detection.
Implementation Method 1
an ultrasonic oscillator; an ultrasonic sensor arranged at a position that opposes the ultrasonic oscillator interposing a transport path of a medium
Implementation Method 2
an amplification circuit configured to amplify an output signal of the ultrasonic sensor
Implementation Method 3
an integration circuit configured to integrate an output signal of the amplification circuit
Implementation Method 4
a discharge circuit configured to perform discharge of an electric charge of a power storage circuit included in the integration circuit
Data Source
AI summary
A medium processing apparatus includes: an ultrasonic oscillator; an ultrasonic sensor arranged at a position that opposes the ultrasonic oscillator interposing a transport path of a medium; an amplification circuit configured to amplify an output signal of the ultrasonic sensor; an integration circuit configured to integrate an output signal of the amplification circuit; a discharge circuit configured to perform discharge of an electric charge of a power storage circuit included in the integration circuit; and a determination circuit configured to determine whether or not multi-feed of the medium occurs on the basis of an output signal of the integration circuit, in which the discharge circuit stops, after performing discharge over a first period or more, the discharge, and after a second period has passed, the determination circuit performs a first (an initial) determination whether or not the multi-feed of the medium occurs.