Image Reading Apparatus Feed Detection Positioning
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Solution Overview
Problem
Image reading apparatuses face reduced throughput due to incorrect detection of binding holes as document ends, leading to overlapping documents and variations in image length read, as existing systems struggle to accurately differentiate between document ends and holes.
Innovation Solution
The image reading apparatus includes a feed unit with a frictional force application portion and a feed detection unit positioned between the pinching point and the tangential line of the feed roller, allowing swift detection of documents and reducing the interval between document feeds, while a control unit adjusts transport speed based on detection signals to prevent overlapping and ensure consistent image length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the document detection sensor is provided in the vicinity of the reading unit to detect the rear end of the document as a trigger for feeding the next document, then the reading unit can start reading using the leading end detection as a trigger, but the interval between documents is widened and the throughput is decreased
Solution Approach 1:
The patent divides the detection function into two separate sensors: a leading end detection sensor positioned near the reading unit to trigger reading, and a rear end detection sensor positioned near the feed unit to trigger feeding of the next document. This segmentation allows independent optimization of reading and feeding operations, enabling the system to maintain short intervals between documents while ensuring complete reading of each document before the next is fed.
2Measurement precision
If the feed detection unit is provided closer to the downstream side to ensure complete document detection, then the detection accuracy is improved, but the interval from when the feeding of the previous document is completed until when the next document is fed is lengthened
Solution Approach 1:
The rear end detection sensor is positioned upstream near the feed unit rather than downstream near the reading unit. This preliminary detection approach allows the system to detect when the current document has been completely fed and prepared for the next document to be fed, without waiting for the document to pass the reading unit. This reduces the idle time between document feeds while maintaining detection accuracy through the separate leading end detection sensor.
3Productivity
If the document detection sensor detects binding holes as the rear end of the document, then the detection system operates continuously, but the documents are fed in an overlapped state (multi-feed) and the reading accuracy is compromised
Solution Approach 1:
The patent introduces a control unit that acts as an intermediary between the detection sensors and the feed/reading operations. The control unit processes signals from both the leading end detection sensor and rear end detection sensor, and intelligently determines when to trigger feeding operations. This intermediary control logic prevents binding holes from being misinterpreted as document rear ends by requiring proper sequencing of detection signals, thereby eliminating multi-feed errors while maintaining continuous feeding capability.
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 configuration enhances throughput by reducing document overlap and maintaining consistent image length, improving the accuracy of document detection and processing efficiency.
Implementation Method 1
a frictional force application portion (20) which applies a frictional force to an opposite side from a transport direction between the frictional force application portion (20) and the document (D) which is fed by the feed roller (19)
Data Source
AI summary
A feed detection unit which detects a document which is fed is provided at a position between a pinching position at which a feed roller and a frictional force application portion pinch the document and an intersecting position at which a tangential line of the feed roller which is closer to a downstream side in a transport direction than the pinching position is perpendicular to a transport path in the transport direction, which is a different position from the feed roller in a width direction which intersects the transport direction.