Linear Image Sensor Alignment Mark Detection
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Solution Overview
Problem
Existing printing devices face complications in detecting the position of alignment marks on different types of paper, requiring manual or motor-driven adjustments of photocells, which increases constructional and operational complexity.
Innovation Solution
A printing device equipped with a linear image sensor, such as a CCD or CIS scanning sensor, is arranged transversely to the paper path to detect alignment marks on the opposite side, allowing for automatic detection without adjusting the sensor position, enabling reading of pre-printed coded data and facilitating printing on various paper types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a photocell is used to detect alignment marks, then detection capability is provided, but constructional and operational complexity increases due to adjustable positioning requirements
Solution Approach 1:
The patent replaces the mechanical photocell positioning system with a linear image sensor that captures images of the alignment mark and processes them electronically. This substitution eliminates the need for mechanical adjustment mechanisms while maintaining detection capability.
Solution Approach 2:
The linear image sensor creates an optical copy (image) of the alignment mark and extracts position information from this copy. This allows the sensor to detect alignment marks at fixed positions without mechanical adjustment, as the image processing system adapts to different mark positions.
2Measurement precision
If the photocell position is adjusted for each paper type, then detection accuracy is maintained, but operational complexity and time consumption increase
Solution Approach 1:
The linear image sensor captures an optical image of the alignment mark, allowing the system to determine the mark's position relative to the paper edges. This enables automatic adaptation to different paper types without manual sensor repositioning, as the image processing system identifies the mark position in each captured image.
Solution Approach 2:
The system uses feedback from the linear image sensor to automatically determine the alignment mark position for each paper type. The detected position information is fed back to the control system, which adjusts printing parameters accordingly, eliminating the need for manual intervention.
3Adaptability or versatility
If a linear image sensor is used to read the second side of paper, then versatility for different paper types is improved, but device complexity increases
Solution Approach 1:
The linear image sensor is positioned to read the second side of the paper, enabling it to detect alignment marks and pre-printed coded data on various paper types. This single sensor arrangement provides universal functionality across different paper types without requiring type-specific sensor configurations.
Solution Approach 2:
The linear image sensor creates an optical copy of the second side of the paper, allowing the system to extract information (alignment marks, coded data) from this copy. This approach enables versatile detection across different paper types using a fixed sensor position, as the image processing system adapts to various paper characteristics.
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 solution simplifies the detection of alignment marks and pre-printed data, reducing operational complexity and enabling seamless printing on any type of paper, while maintaining a constructionally simple and cost-effective design.
Implementation Method 1
a (linear) image sensor, which is arranged along a path of the paper transversely to an advancement direction of the paper to read a second side of paper opposite the first
Data Source
AI summary
A printing device is disclosed including a path for supplying thermal paper unwound from a roll to a thermal print head arranged for printing on a first side of paper, wherein a linear image sensor is arranged along the path, on a second side of paper opposite the first, transversely to an advancement direction of the paper, to detect the position of an alignment mark arranged on the paper.