Printing Machine Powder Control via Reference Area Measurement
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Solution Overview
Problem
Existing methods for controlling powder devices in printing presses based on powder density measurements are unreliable due to variations in print images and substrate optical densities, leading to inconsistent measurement results.
Innovation Solution
Measuring powder density outside the printed image area, using a print control strip with designated measuring fields, and employing an optical measuring device that takes multiple readings across the sheet to ensure high process reliability and reproducibility, with optional background comparison measurements and protective measures for the measuring device optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If optical measurement is performed within the printed image area, then the measurement can be integrated with the printing process, but the measurement results vary due to print image variations and substrate optical density differences
Solution Approach 1:
The patent divides the sheet into different measurement zones: printed image areas and non-printed reference areas. By segmenting the measurement location to exclusively use non-printed areas (such as margins or registration marks), the method isolates the measurement from variations in print image and substrate optical density, thereby ensuring consistent and reproducible measurements while maintaining process integration.
2Reliability
If multiple measurements are taken across different areas of the sheet, then measurement reliability improves, but measurement time and system complexity increase
Solution Approach 1:
The patent extracts the measurement function from the printed image area and relocates it to dedicated reference areas that are specifically designed for measurement purposes. These reference areas contain uniform patterns (such as solid color fields or registration marks) that provide consistent optical properties. By taking out the measurement requirement from variable print areas and placing it in controlled reference areas, the system achieves high reliability without requiring multiple measurements across the entire sheet, thus reducing measurement time.
3Measurement precision
If the measuring device optics are exposed during measurement, then measurement accuracy is maintained, but the optics are contaminated by powder particles
Solution Approach 1:
The patent implements preliminary protective actions by providing covers for the measuring device optics that can be opened only when measurement is required and closed during powder application and sheet handling. This preliminary protection setup ensures that the optics remain clean and uncontaminated by powder particles while still allowing accurate measurements to be taken when the covers are temporarily opened during the measurement process.
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
Ensures high process reliability and reproducibility by isolating measurement influences from the printed image, providing accurate powder control and maintaining measurement device integrity.
Implementation Method 1
optical measuring device that takes multiple readings across the sheet
Data Source
Figure 1
Figure 2~5
AI summary
The method involves carrying out the measurement of parameters in one or more measuring fields on a printed sheet (7). The parameters are correlated with the powder quantity on the sprayed printed sheets that are placed outside the printing images (8). A background-comparison measurement is carried out before spraying the printed sheet with the powder.