Document Transport Speed Detection Using Optical Sensors
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Solution Overview
Problem
Existing document feeding mechanisms require a significant gap between documents to be detected before downstream operations can begin, leading to inefficiencies and a need for longer document transport paths, as sensors need a large gap to accurately detect document separation from the low speed drive.
Innovation Solution
A surface motion sensor, such as a light source, detector, and optical wheel, is used to monitor the speed change of documents as they transition from a low speed to a high speed drive, allowing immediate detection of document disengagement from the low speed drive and triggering downstream processing without requiring a specific gap size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is used to detect gap between documents, then document separation can be detected, but a relatively large gap is required which increases document transport path length
Solution Approach 1:
The patent replaces the mechanical gap detection system with an optical system. Instead of using a physical sensor that requires a large mechanical gap to detect document separation, an optical sensor detects the reflection characteristics of documents. The optical sensor can detect document presence and separation based on light reflection properties rather than physical gap measurement, eliminating the need for a long transport path.
Solution Approach 2:
The invention changes the detection parameter from physical gap size to optical reflection characteristics. By monitoring changes in light reflection as documents move through the transport path, the system can detect document separation without requiring a minimum gap distance. This parameter transformation allows for shorter transport paths while maintaining detection accuracy.
2Reliability
If a large gap is created between documents for sensor detection, then document separation is reliably detected, but downstream operations are delayed
Solution Approach 1:
The optical detection system replaces mechanical gap measurement, enabling reliable document separation detection without requiring documents to travel a long distance. The optical sensor can detect separation events in real-time as documents pass through the transport path, eliminating the time delay associated with waiting for a large gap to form.
Solution Approach 2:
The system allows documents to move quickly through the transport path without pausing to create a large gap. The optical sensor continuously monitors document positions and triggers downstream operations immediately upon detecting separation, rather than waiting for a predetermined gap size to be achieved. This rushing through approach maintains reliability while minimizing delay.
3Length of moving object
If document transport path is lengthened to accommodate gap formation, then sufficient gap size is achieved for detection, but apparatus size increases
Solution Approach 1:
The patent replaces mechanical gap formation with optical detection. Instead of designing a long transport path to physically create detection-capable gaps, the optical sensor detects document separation based on light reflection properties. This substitution allows for a compact apparatus design while maintaining accurate separation detection capability.
Solution Approach 2:
The invention transitions from one-dimensional mechanical gap measurement to optical detection that can sense separation characteristics in different dimensions. The optical sensor detects reflection patterns that indicate document separation without requiring physical distance, effectively using optical field dimensions rather than mechanical space dimensions.
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 approach enables immediate initiation of downstream operations upon detection of speed change, reducing the need for a large gap and allowing for a more compact document processing apparatus by eliminating the requirement for a specific gap size between documents, thus enhancing processing efficiency and reducing apparatus size.
Implementation Method 1
A sensor is positioned along the document transport path to detect the presence of the gap. The sensor provides an electrical signal when a gap of sufficient size is detected
Implementation Method 2
A surface motion sensor, such as a light source, detector, and optical wheel, is used to monitor the speed change of documents
Data Source
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AI summary
A document processing apparatus is described. The apparatus comprises: a document transport path which extends from an upstream end to a downstream end; a low speed drive; a high speed drive; an actuatable document processing device disposed at the downstream end of the document transport path and for, when actuated, performing a downstream processing operation on a document being transported along the document transport path; a sensor for (i) sensing speed of movement of a document which is being transported along the document transport path, and (ii) providing a first electrical signal which is indicative of speed of movement of the document; and a controller for (i) monitoring the first electrical signal to thereby monitor speed of movement of the document along the document transport path, (ii) detecting when the speed of movement of the document has increased from a first speed to a second speed, (iii) providing a second electrical signal to actuate the document processing device to perform the downstream processing operation in response to detection of speed of movement of the document having increased from the first speed to the second speed.