Print Image Uniformity Calibration via Detector Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing print image detection methods, particularly using RGB line cameras, incur errors due to imaging and detection errors, leading to inhomogeneous print image detection across the scan width, which can result in degradation of print quality when correcting inking intensity.
Innovation Solution
A method and device that calibrate the image detector by printing test images with constant inking intensity, generating measured value profiles, and comparing them to references to store correction values for the image detector and print nozzles, ensuring uniform inking intensity across the print width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an RGB line camera is used to detect print image uniformity, then the detection process can be performed, but imaging and detection errors cause inhomogeneous detection results across the scan width
Solution Approach 1:
The patent applies preliminary action by performing calibration of the image detector before actual print image detection. A calibration print image with uniform inking is detected first to generate correction values that compensate for the RGB line camera's inherent detection errors across different scan width regions. These correction values are stored and applied during subsequent detection operations, ensuring reliable and consistent measurements.
Solution Approach 2:
The patent implements feedback by using the detected calibration print image data to generate correction values that are fed back into the detection system. The measured inking intensities from the calibration image are compared against expected uniform values, and the differences are used to create correction factors that are applied to subsequent detections, continuously improving measurement accuracy.
2Manufacturing precision
If correction values are determined for each printing element based on test print images, then print image uniformity can be improved, but the calibration process becomes time-consuming and complex
Solution Approach 1:
The patent applies segmentation by dividing the calibration process into distinct stages: first detecting a calibration print image to identify detection errors, then generating correction values for each image detection region, and finally applying these corrections to print head activation values. This segmented approach allows systematic correction of uniformity issues without requiring exhaustive recalibration of each individual printing element.
Solution Approach 2:
The patent uses parameter changes by modifying the activation values of print heads based on detected uniformity deviations. The system adjusts printing parameters (activation values) according to the correction values derived from the calibration image, thereby compensating for manufacturing variations and wear in printing elements to achieve uniform print output.
3Stability of the object's composition
If correction values are stored for print heads to compensate for manufacturing and wear differences, then print image consistency can be maintained, but the system complexity increases
Solution Approach 1:
The system performs preliminary calibration to determine correction values for each print head before actual printing operations. These correction values are stored in advance and automatically applied during normal operation, maintaining print consistency without requiring complex real-time adjustments or additional hardware during the printing process itself.
Data Source
AI summary
In a device and a method for improving the print image uniformity, at least one print image is printed by a printer with at least one print bar that has at least one print head with a plurality of print nozzles. An image detector having a plurality of dot/image detection regions detects at least one value profile of measured inking intensities. A comparator compares the value profile with at least one reference value, and generates correction values dependent thereon.