Register Measurement Without Marks Using Color Control Strips
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Solution Overview
Problem
Current methods for automated register measurement in printing processes require separate evaluation systems and register marks, which are inefficient and often combine register offset correction with color control, leading to suboptimal results, especially under high quality requirements.
Innovation Solution
A method using a computer to evaluate register offsets from existing color control strips, adapting color measurement fields to determine circumferential and side register offsets without the need for a separate register sensor or marks, leveraging the image acquisition system for inline evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate register sensor and register marks are used for automated register measurement, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The image acquisition system originally designed for color control is made multi-functional by enabling it to perform both color measurement and register offset detection. The same system captures images of color control strips containing both color measurement fields and register marks, allowing a single device to execute multiple quality control functions without requiring separate dedicated sensors or evaluation systems.
Solution Approach 2:
The evaluation of color control and register measurement is merged into a single integrated process. The computer evaluates both the color measurement fields and register marks from the same captured image data, combining what were previously separate evaluation tasks into one unified workflow, thereby reducing system complexity while maintaining measurement precision.
2Measurement precision
If image resolution is increased to enable existing cameras to capture register marks accurately, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The existing image acquisition system is utilized for dual purposes: color control evaluation and register measurement. By making the system multi-functional, there is no need to upgrade to higher resolution cameras or increase imaging frequency, thus avoiding additional energy consumption while still achieving accurate register mark detection through proper image processing of the captured data.
3Device complexity
If color control strip is adapted to include register marks, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The color control strip is segmented into distinct functional zones: color measurement fields for color control and register marks for registration verification. This segmentation allows each element to be optimized for its specific purpose while maintaining overall integration. The register marks are positioned in specific geometric arrangements that enable accurate offset detection without interfering with color measurement functionality.
Solution Approach 2:
Different regions of the color control strip are designed with locally optimized characteristics. The color measurement fields are designed with specific colorimetric properties for accurate color evaluation, while the register marks are designed with specific geometric properties for precise registration measurement. Each local region has quality characteristics tailored to its specific measurement function.
Data Source
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AI summary
Method for automated register measurement of color separations in a printing process of a printing press (14) by a computer (13, 16), wherein at least one test pattern (1) is captured by at least one image sensor (15) and stored in a digital composite image, the computer (13, 16) evaluates the captured test pattern (1) with respect to a register offset (2, 3) and corrects it, wherein the computer (13, 16) uses a color control strip (1) as the test pattern (1) and adjusts the color measurement fields of the color control strip (1) so that the computer (13, 16) can determine the circumferential and lateral register offset (2, 3) from the color control strip (1a, 1b, 6) captured and digitized by means of the image sensor (15), which is characterized in that the computer (13, 16) uses the sequence of the color measurement fields of the color control strip (1a, 1b, 1b) to measure the lateral register offset.6) adjusts to the visibility of an overlapping print of the color measurement fields.