Laser Triangulation Double-Feed Detection for Mail Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing double-feed detection systems in mail processing machines are ineffective in handling variable item thickness, perfect superimposition, and false double-feeds, particularly in high-speed processing of mixed flat items.
Innovation Solution
A system using a laser detection device mounted at a tilt angle to scan the front end and face of moving flat items, employing a triangulation sensor and controller to generate signals indicative of distance and profile, differentiating true double-feeds from false ones, and incorporating a profile database for accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional double-feed detection systems are used, then detection capability is provided, but they fail to handle variable item thickness, perfect superimposition, and false double-feeds effectively
Solution Approach 1:
The system changes the parameter of detection angle by mounting the laser detection device at a specific tilt angle (e.g., 45 degrees) relative to the transport deck. This angular parameter change enables the laser beam to scan both the front end part and front face of moving flat items simultaneously, creating a detection geometry that naturally distinguishes between true double-feeds and false double-feeds caused by variable thickness or perfect superimposition.
Solution Approach 2:
The invention adds a dimensional aspect to detection by using a laser beam that scans across both the length (front end) and height (front face) of items in a single tilted pass. This two-dimensional scanning approach in the tilted plane provides additional detection information that conventional single-plane sensors cannot capture, enabling differentiation of various double-feed conditions.
2Productivity
If high-speed processing is implemented, then productivity increases, but double-feed detection becomes more difficult and error-prone
Solution Approach 1:
The laser detection device operates continuously at high speed, maintaining constant scanning of the moving flat items throughout the transport process. The tilted mounting ensures continuous detection of both front end and front face positions without interruption, allowing the system to maintain high processing speeds while preserving detection accuracy through uninterrupted measurement.
Solution Approach 2:
The invention replaces complex mechanical detection mechanisms with an optical laser-based system. The laser triangulation method uses light reflection and optical sensing instead of mechanical contact or complex sensor arrays, enabling high-speed non-contact detection that maintains precision even at elevated processing speeds where mechanical systems would struggle.
3Measurement precision
If laser detection device is mounted at tilt angle to scan front end and face, then detection precision improves, but device complexity increases
Solution Approach 1:
The tilted laser detection device serves multiple functions simultaneously: it detects front end position, front face position, item thickness variations, and double-feed conditions all through a single mounting configuration. This multi-functionality reduces the need for separate detection devices for each parameter, thereby limiting the increase in overall device complexity while maintaining high detection precision.
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
The system efficiently detects double-feeds at high speeds, reducing operator involvement and addressing issues of variable thickness and perfect superimposition, with precise detection of double-feeds even at low rates, ensuring reliable operation and reduced machine downtime.
Implementation Method 1
receiving at least a portion of the beam of radiation reflected from them
Implementation Method 2
a triangulation sensor for providing an output proportional to a position at which the reflected portion of the beam is received on it, and means for determining from said output, the distance d between the radiation source and the point of reflection
Data Source
AI summary
A system for detecting double-feed flat item conveyed in a mail processing machine, including a detection for directing a beam of radiant energy toward the moving flat items, scanning them with the beam and receiving at least a portion of the beam of radiation reflected from them. The detector includes a triangulation sensor for providing an output proportional to the position at which the reflected portion of the beam is received, and means for determining from the output, the distance (d) between the radiation source and the point of reflection of the beam on the moving flat items, and providing a signal (S) representative of said distance; and a controller configured to receive the signal (S) and generate an output signal (V) indicative of a flat item profile and a double-feed condition when it detects a significant break point or slope change of the signal from a first direction to a second direction.