Ultrasonic Multi-Sheet Feed Detection Using Adaptive Voltage
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Solution Overview
Problem
Existing image reading apparatuses face challenges in accurately detecting multi-sheet feed due to factors like high altitude, sensor deterioration, and position shifts, leading to erroneous determination of single sheet feed as multi-sheet feed.
Innovation Solution
The apparatus employs a control unit that adjusts the driving voltage of an ultrasonic wave sensor, determining multi-sheet feed based on the change in reception level signal, distinguishing between single and multi-sheet feed by a reference amount of change in the signal when the voltage is increased.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed threshold is used for multi-sheet feed detection, then the detection method is simple, but detection accuracy deteriorates due to environmental factors and sensor deterioration
Solution Approach 1:
The patent applies dynamics by making the detection threshold adaptive rather than fixed. The threshold is dynamically adjusted based on the reception level signal characteristics, allowing the system to adapt to environmental changes and sensor deterioration while maintaining accurate multi-sheet feed detection
Solution Approach 2:
The patent changes the detection parameter from a fixed threshold to a dynamically determined threshold based on signal characteristics. By monitoring changes in the reception level signal and adjusting the threshold accordingly, the system maintains high detection accuracy under varying conditions
2Measurement precision
If the ultrasonic wave sensor operates at high sensitivity, then single sheet feed can be detected, but false positive multi-sheet feed detection increases
Solution Approach 1:
The patent uses feedback by continuously monitoring the reception level signal and using this information to adjust the detection threshold. The system feeds back the signal characteristics to the threshold determination mechanism, enabling it to distinguish between single sheet feed and multi-sheet feed more reliably
Solution Approach 2:
The patent performs preliminary action by establishing an adaptive threshold before making the final detection decision. The system first analyzes the reception level signal characteristics and sets an appropriate threshold, then uses this pre-established threshold for accurate detection, preventing false positives
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 method enhances the accuracy of multi-sheet feed detection, reducing false positives and improving user convenience by correctly identifying single sheet feed even in challenging environments.
Implementation Method 1
a transmission unit and a reception unit disposed at positions sandwiching a transport path of the medium transported by the transport unit, the transmission unit being configured to emit an ultrasonic wave in accordance with a driving voltage
Implementation Method 2
the reception unit being configured to receive the ultrasonic wave, a reading unit configured to read the medium transported by the transport unit, and a control unit configured to detect occurrence or non-occurrence of multi-sheet feed
Data Source
AI summary
An image reading apparatus includes a control unit configured to detect occurrence or non-occurrence of multi-sheet feed of a medium based on a reception level signal output by a reception unit in accordance with the received ultrasonic wave. The control unit, after a tip of the medium reaches the positions of the reception unit in a transport path, when the reception level signal is below a predetermined threshold, causes the driving voltage to rise, when an amount of change in the reception level signal in accordance with the rise in the driving voltage is smaller than a reference amount of change, determines that multi-sheet feed is ongoing, and when the amount of change in the reception level signal in accordance with the rise in the driving voltage is greater than the reference amount of change, determines that multi-sheet feed is not ongoing.