ADF Skew Detection via Image Analysis and Airflow Transport
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Solution Overview
Problem
Conventional image reading devices with automatic document feeding (ADF) mechanisms require complex and costly transport mechanisms for handling documents of varying sizes, and often struggle to efficiently detect and prevent document skew during transport.
Innovation Solution
An image reading device with a controller that uses image data from dedicated readers to detect tilt in documents and adjust the transport path, allowing for efficient detection and prevention of skew by stopping transport when tilt is detected and correcting image data based on tilt angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional ADF uses transport rollers and motors to transport documents at pitch corresponding to business card size, then the document transport function is achieved, but the transport mechanism becomes complicated and costly
Solution Approach 1:
The patent replaces the conventional mechanical transport mechanism (transport rollers and motors) with an airflow-based system. A blowing fan generates air flow that transports documents through the ADF, eliminating the need for complex mechanical components while maintaining the ability to handle various document sizes including business cards
Solution Approach 2:
The patent uses pneumatic principles by introducing a blowing fan that generates air flow to transport documents. The air flow carries documents through the transport path, replacing mechanical roller-based transport with a pneumatic system that is simpler and more adaptable to different document sizes
2Reliability
If a dedicated sensor is used to prevent damage and skew of the document, then document protection is improved, but the device complexity and cost increase
Solution Approach 1:
The patent employs the document reader itself to detect document skew by analyzing the read image data. The system automatically identifies skew angles from the captured image and adjusts the transport or processing accordingly, eliminating the need for separate dedicated skew detection sensors while maintaining document protection and reading accuracy
Solution Approach 2:
The patent implements a feedback mechanism where the read image data is analyzed to detect document skew, and this information is fed back to control the transport mechanism or image processing. The system automatically adjusts based on the detected skew angle, providing closed-loop control without additional sensors
3Measurement precision
If the document transporter stops transport when tilt is detected, then reading accuracy is improved, but the productivity decreases
Solution Approach 1:
The patent applies partial correction by detecting the skew angle and only adjusting the transport or processing to the extent needed to correct the skew. Rather than stopping completely for all documents, the system selectively corrects only those documents with detectable skew, maintaining high productivity while ensuring reading accuracy for affected documents
Data Source
AI summary
An image reading device reads two types of documents, a first document having a first size and a second document having a second size larger than the first size. A controller of the device causes the first document reader to read the first document and generate image data when the operation unit accepts a command. The first document reader reads a portion of the second document and generates image data on tilt of the second document when the operation unit accepts a command. The document tilt detector detects tilt of the second document based on the image data for detecting tilt of the second document. The document transporter stops transport of the second document when the document tilt detector detects tilt of the second document. The second document reader reads the second document and generates image data when the document tilt detector detects no tilt of the second document.