Out-of-plane reflection for label edge detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for detecting the presence and position of pressure-sensitive labels, particularly butt-cut labels, are inefficient due to reliance on registration marks, sensitivity to optical properties, and difficulty in distinguishing label edges from the liner, especially with varying materials and adhesives, leading to inaccuracies and potential jams.
Innovation Solution
A photoelectric sensor system that uses a small-diameter light beam inclined at a predetermined angle to detect label edges by exploiting the angularity and curvature of die-cut and butt-cut labels' edges, allowing for edge detection without registration marks and regardless of material or optical properties, and can differentiate between label types based on the sequence of light reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If photoelectric sensors are used to detect labels, then detection speed and automation are improved, but detection reliability deteriorates due to sensitivity to varying optical properties of different label and liner materials
Solution Approach 1:
The patent changes the detection parameter from direct transmission light intensity to out-of-plane reflected light intensity. By detecting light reflected at angles outside the plane of incidence, the system becomes insensitive to the optical properties (transparency, color, gloss) of the label and liner materials, while maintaining automated detection capability
Solution Approach 2:
The patent replaces the conventional photoelectric detection mechanism (measuring light transmission or in-plane reflection) with an alternative mechanism (measuring out-of-plane reflection). This substitution eliminates the sensitivity to material optical properties while preserving the non-contact, automated detection approach
2Device complexity
If conventional photoelectric detection methods are used, then detection simplicity is maintained, but measurement precision deteriorates due to inability to distinguish label edges from liner especially with butt-cut labels
Solution Approach 1:
The patent moves the detection from the plane of incidence (conventional 2D detection) to an out-of-plane dimension. By detecting light reflected at angles outside the incidence plane, the system creates a new detection dimension that provides edge contrast without requiring complex registration marks or partial label removal
3Measurement precision
If registration marks are added to labels or liner to enable detection, then detection accuracy is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the detection function from the label structure itself. Instead of requiring registration marks printed on the label or liner, the system uses the natural light reflection properties of the label edges, eliminating the need for additional detection features while maintaining detection accuracy
Solution Approach 2:
The label edges themselves serve as the detection feature through their natural light reflection properties. The sharp edges of die-cut and butt-cut labels automatically provide the out-of-plane reflection signal needed for detection, eliminating the need for external registration marks or additional detection infrastructure
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
Enables reliable detection of both die-cut and butt-cut labels' edges across various materials and optical characteristics without adjustments, improving positional accuracy and reducing the risk of jams, while eliminating the need for registration marks.
Implementation Method 1
A first photoelectric sensor sequentially detects an intensity profile of light reflected off the web as the web moves in the direction of motion. The first photoelectric sensor is positioned to detect light reflected off the web at angles outside the plane of incidence
Data Source
AI summary
This disclosure describes an optical method of detecting the presence of pressure-sensitive labels, using the reflective properties of their edges. Labels that are removably attached to a liner are moved through a light beam that is directed across their direction of motion so the light impinges on the labels at a predetermined angle of incidence. The light remains in its plane of incidence when it reflects off all parts of the liner and labels except the labels' edges. Due to the angularity of the labels' edges, the light beam is deflected out of the plane of incidence upon reflection off the edges, thus enabling detection of the label edges by light reflected out of the plane of incidence.