Optical Medium Detector for Overlap Detection in Automatic Document Feeders
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Solution Overview
Problem
Image reading apparatuses with automatic document feeders often fail to read images properly when original sheets overlap, and may erroneously detect thick documents like cards as overlapping, leading to unnecessary operation disruptions.
Innovation Solution
The apparatus includes a feeder, a multi-feed detector, a reader, and a medium detector with a light transmitter and receiver, where the light quantity is varied to determine if media overlap, allowing the controller to skip unnecessary detection processes for thick media, thereby reducing false positives in overlap detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the overlap detection function is enabled to detect overlapping original sheets, then the reading accuracy is improved, but false detection occurs with thick single sheets causing operation disruption
Solution Approach 1:
The detection process is segmented into two independent stages: first detecting medium presence/absence at the medium detection location, then detecting overlap at the multi-feed detection location. This segmentation allows the system to handle thick media and overlapping media through different detection pathways, preventing false positives while maintaining detection accuracy.
Solution Approach 2:
The system performs preliminary detection of medium presence/absence before performing overlap detection. By first determining whether a medium is present at the medium detection location, the system can then decide whether to proceed with overlap detection at the multi-feed detection location, avoiding false detection of thick media as overlaps.
2Measurement precision
If the light quantity is increased to detect thick media, then the detection capability for thick media is improved, but the energy consumption increases
Solution Approach 1:
The system applies partial action by using a first light quantity sufficient for basic medium presence detection, and only increases to a second light quantity when thick media detection is specifically required. This partial application of excessive light quantity reduces overall energy consumption while maintaining the capability to detect thick media when needed.
Solution Approach 2:
The system dynamically changes the light quantity parameter based on detection requirements. By switching between a first light quantity for normal operation and a second light quantity for thick media detection, the system optimizes energy consumption while maintaining detection capability across different media types.
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 solution effectively reduces the likelihood of incorrectly determining media overlap, especially with thick documents, allowing for uninterrupted reading operations without the need for dedicated sensors for thick media detection.
Implementation Method 1
a light transmitter that emits light with a light quantity to the medium detection location, the light quantity being variable, and a light receiver that receives the light that traveled across the transport route
Data Source
AI summary
When a medium detector detects that a state where a medium is absent is switched to a state where the medium is present with a light quantity of the medium detector set to a first light quantity, a controller in an image reading apparatus switches the light quantity from the first light quantity to a second light quantity, which is larger than the first light quantity. When a quantity of the light received by the medium detector exceeds a threshold, the controller determines whether the media overlaps each other, based on the detection result of the multi-feed detector. When the quantity of the light received does not exceed the threshold, the controller skips the determination of whether the media overlaps each other.