Image Scanner Skew Detection with Dual Sensor Zones
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Solution Overview
Problem
Existing image reading apparatuses frequently stop document transport unnecessarily due to erroneous skew detection, especially when dealing with documents of varying widths, leading to potential damage and inefficiency.
Innovation Solution
The implementation of second detection sections between first detection sections in the medium width direction allows for more accurate assessment of transport states, enabling the continuation of transport for skewed or narrow documents, and the use of additional detection sections to prevent paper jams by detecting end portion misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pair of document-width sensors is used to detect skewed documents, then skew detection capability is improved, but unnecessary transport stops occur when documents have width close to sensor distance
Solution Approach 1:
The detection system is segmented into multiple independent detection sections (first detection sections and second detection sections) arranged at different positions. Instead of using a single pair of sensors, the patent divides the detection function across multiple sections, allowing each section to independently evaluate document presence and skew status, thereby reducing false positives that cause unnecessary transport stops.
2Reliability
If document transport is stopped when skew exceeds threshold, then document damage is prevented, but legitimate documents are incorrectly halted
Solution Approach 1:
The system implements feedback control by continuously monitoring document transport status through multiple detection sections and dynamically adjusting transport continuation decisions. The controller receives feedback from both first and second detection sections, evaluates their combined information, and makes informed decisions about whether to continue or stop transport, reducing incorrect halts while maintaining document safety.
3Measurement precision
If detection sections are placed close together, then detection accuracy is improved, but narrow documents may be missed
Solution Approach 1:
The patent extends the detection system from a single row of sensors to a two-dimensional arrangement with detection sections positioned at different locations (first detection sections and second detection sections at different positions in the medium transport direction). This spatial dimensionality change allows the system to detect documents of various widths by having multiple detection planes, improving both accuracy and adaptability to different document sizes.
Data Source
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AI summary
An image reading apparatus includes a pair of first detection sections disposed between first positions for the feeding rollers and the separation rollers for nipping and second positions for the transport roller pair for nipping, and a pair of second detection sections disposed between the first detection sections and the second positions in the medium transport direction. The second detection sections are disposed between the first detection sections in the medium width direction, and a controller determines whether to stop transporting the medium or continue transporting the medium based on the results of detection by the first detection sections and the second detection sections.