Ultrasonic Sensor for Document Fold Detection in Scanners
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Solution Overview
Problem
Existing image reading apparatuses struggle to prevent paper jams caused by folds or wrinkles in documents during transportation, often resulting in damage due to inadequate detection methods.
Innovation Solution
An image reading apparatus equipped with an ultrasonic wave sensor system that differentiates between single sheets and multi-sheets, and detects folds or wrinkles by evaluating output values against specific conditions, halting transport when necessary to prevent jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a simple transport amount-based determination method is used to detect jams, then the detection process is simple and fast, but document damage occurs because the determination is made after the document has already been damaged by continuous transport
Solution Approach 1:
The patent applies preliminary action by detecting document abnormalities (folds, wrinkles, multi-feeding) using ultrasonic waves during the transport process, before the document reaches the reading section where damage would occur. The system continuously monitors document state and halts transport preemptively when abnormalities are detected, preventing damage before it happens rather than detecting damage after it occurs.
2Reliability
If the transport path is narrowed to prevent multi-feeding, then multi-feeding is reduced, but documents with folds or wrinkles are more likely to cause jams in the narrow reading section
Solution Approach 1:
The system performs preliminary detection of folds and wrinkles in documents during the wider upstream transport section before they enter the narrow reading section. By detecting these abnormalities early and halting transport when necessary, the system prevents documents with potential jam-causing defects from entering the constrained reading area, thus eliminating paper jams without requiring path narrowing.
Solution Approach 2:
The ultrasonic wave sensor acts as an intermediary detection mechanism between the feeding means and the reading section. It provides indirect detection of document abnormalities by measuring ultrasonic wave transmission characteristics, allowing the system to identify folds and wrinkles without physically constraining the document path, thus avoiding the trade-off between path narrowing and jam prevention.
3Device complexity
If the ultrasonic wave sensor detects only multi-feeding, then the detection system is simple, but documents with folds or wrinkles that are not multi-fed are not detected and continue to cause jams
Solution Approach 1:
The patent applies parameter changes by utilizing different ultrasonic wave transmission parameter thresholds to distinguish between different document states. The system compares ultrasonic wave transmission intensity against predetermined thresholds to detect multi-feeding versus single-sheet conditions, and further analyzes transmission characteristics to identify folds and wrinkles. This allows a single sensor system to detect multiple document abnormalities by interpreting variations in ultrasonic wave parameters.
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
Effectively minimizes paper jams by accurately identifying and halting the transport of documents with folds or wrinkles, reducing operational failures and document damage.
Implementation Method 1
a transmitting portion configured to emit an ultrasonic wave and a receiving portion configured to receive the ultrasonic wave emitted from the transmitting portion
Data Source
AI summary
An image reading apparatus includes a feed roller configured to feed paper toward a reading section, and a medium detection section provided along a transport path between the feed roller and the reading section and configured to include a transmitting portion configured to output an output value equivalent to a magnitude of an ultrasonic wave, and determines whether the transport of the paper is to be continued or to be brought to a halt on the basis of a lower limit value and an upper limit value for the output value, which are set in accordance with the kind of the paper. Further, in a case where the output value satisfies a first condition, a transport of the medium is continued, and in a case where the output value satisfies a condition different from the first condition, the transport of the medium is brought to a halt.