Ultrasonic Multi-feed Detection with Vibration Skip
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Solution Overview
Problem
Existing paper conveyance devices using ultrasonic sensors face challenges in accurately detecting multi-feed due to vibrations applied to the paper, leading to false detection of multi-feed occurrences.
Innovation Solution
The implementation of a paper conveyance device with a multi-feed detection unit that includes an ultrasonic sensor and a charge circuit, where the control unit sets detection sections and skip sections based on the timing of vibrations, allowing for accurate determination of multi-feed by distinguishing between actual multi-feed and vibration-induced signal attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic wave transmission is used for multi-feed detection, then multi-feed detection capability is improved, but false detection due to paper vibration occurs
Solution Approach 1:
The detection section is divided into multiple sub-sections along the paper conveyance direction. By segmenting the detection area, the system can identify localized multi-feed events more accurately and distinguish them from vibration effects that may occur at different positions and times.
Solution Approach 2:
The system uses feedback from multiple detection points to verify multi-feed occurrence. When ultrasonic reception levels indicate potential multi-feed at multiple segmented positions, the system confirms the condition through cross-validation of detection results across segments, reducing false positives from vibration.
2Area of stationary object
If continuous ultrasonic wave transmission is used, then detection coverage is improved, but vibration-induced false detection increases
Solution Approach 1:
Instead of continuous ultrasonic transmission, the system uses periodic transmission with specific cycles. This allows time intervals between transmissions to let vibration effects subside, while still maintaining adequate detection coverage through repeated measurements at different time points.
Solution Approach 2:
The system performs preliminary detection actions by transmitting ultrasonic waves at specific intervals before final multi-feed determination. This preliminary scanning allows the system to identify potential issues while avoiding the peak vibration periods that cause false detection.
3Measurement precision
If ultrasonic detection is performed at all detection sections, then detection thoroughness is improved, but processing complexity increases
Solution Approach 1:
The detection section is divided into multiple sub-sections, allowing the control unit to process detection data in manageable segments. This segmentation reduces the computational burden compared to analyzing the entire detection area as a single unit, while maintaining thorough detection coverage.
Solution Approach 2:
Different detection sections can use different detection parameters or thresholds optimized for their specific locations. This local optimization allows thorough detection in each section while reducing overall processing complexity by avoiding uniform high-complexity processing across all sections.
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 approach effectively reduces false detection of multi-feed, ensuring accurate detection and preventing paper jams by considering the impact of vibrations on the ultrasonic signals during paper conveyance.
Implementation Method 1
The transmission unit transmits an ultrasonic wave
Implementation Method 2
The reception unit outputs an electric charge corresponding to the level of the received ultrasonic wave
Data Source
AI summary
A paper conveyance device includes a paper feed unit, a conveyance rotator, a conveyance guide, a multi-feed detection unit, and a control unit. The control unit causes an ultrasonic sensor to transmit an ultrasonic wave in a detection section. The control unit sets a detection execution section and a detection skip section in the detection section. The control unit does not determine whether multi-feed has occurred in the detection skip section. The control unit sets the detection skip section based on a time point at which vibration is applied to conveyed paper.