Sheet Transport Ultrasonic Detection for Thickness-Based Multiple Feed Discrimination
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Solution Overview
Problem
Existing sheet transport systems using ultrasonic sensors often incorrectly detect multiple feeding due to variations in sheet thickness, leading to false detection of thick sheets as multiple paper sheets.
Innovation Solution
Incorporating an ultrasonic sensor with a type detector to differentiate between thinner and thicker sheets, adjusting the ultrasonic sensor's output based on sheet thickness to accurately detect multiple feeding, and using a path switching mechanism to route sheets appropriately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common threshold value is used for all sheet types in ultrasonic detection, then the device complexity is reduced, but measurement precision deteriorates due to false detection of thick sheets as multiple feeding
Solution Approach 1:
The patent changes the detection parameter by introducing a reference value specific to each sheet type (paper, card, etc.) instead of using a common threshold for all sheets. The control unit stores multiple reference values corresponding to different sheet types and selects the appropriate reference value based on the detected sheet type, thereby improving detection accuracy without significantly increasing system complexity
Solution Approach 2:
The patent replaces the mechanical/manual threshold adjustment method with an automated electronic system. The control unit automatically selects and applies the appropriate reference value based on the sheet type detected by the type detector, eliminating the need for manual intervention and reducing operational complexity while improving precision
2Device complexity
If ultrasonic sensor output is used directly for multiple feed detection, then the detection process is simplified, but false detection occurs due to variations in sheet thickness
Solution Approach 1:
The patent introduces a type detector as an intermediary component between the ultrasonic sensor and the multiple feed detection logic. The type detector first identifies the sheet type (paper, card, etc.), and this information is used by the control unit to select the appropriate reference value for accurate multiple feed detection, thereby eliminating false detections caused by thickness variations
Solution Approach 2:
The patent implements a feedback mechanism where the type detector continuously monitors sheet type and provides this information to the control unit, which then adjusts the reference value accordingly. This closed-loop feedback system ensures that the detection threshold always matches the current sheet type, improving reliability while maintaining process simplicity
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 false detection of multiple feeding across different sheet thicknesses, reducing document re-separation and re-transportation, and enhances throughput by correctly routing sheets along appropriate transport paths.
Implementation Method 1
an ultrasonic sensor including an ultrasonic transmitter and an ultrasonic receiver disposed opposite each other across a sheet transport path
Data Source
AI summary
Provided are a sheet transport apparatus and a sheet transport method preventing false detection of multiple feeding when feeding sheets of different thicknesses. The sheet transport apparatus includes an ultrasonic sensor including an ultrasonic transmitter and an ultrasonic receiver disposed opposite each other across a sheet transport path, a type detector for discriminating between a first sheet and a second sheet thicker than the first sheet while one or the other of the sheets is being fed along the transport path, and a multiple feed detector for detecting the presence or absence of multiple feeding of sheets along the transport path, based on an output produced by the ultrasonic sensor and on a detection result supplied from the type detector.