Inkjet Carriage Illumination Brightness Correction
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Solution Overview
Problem
Printing apparatuses with a light source disposed at a predetermined angle relative to the print medium suffer from brightness unevenness, which affects the accuracy of captured image data for test patterns, leading to potential inaccuracies in ink ejection timing adjustments.
Innovation Solution
A printing apparatus with a processor that generates adjusted captured image data by calculating based on both unprinted area and test pattern image data, using shading correction to mitigate brightness unevenness, and optionally applying filter processing on unprinted area data to smooth textures, while maintaining unfiltered processing for test pattern data to ensure accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light source is disposed at a predetermined angle to irradiate the print surface, then the illumination coverage is improved, but brightness unevenness occurs in the capturing area
Solution Approach 1:
The system performs preliminary capture of brightness distribution data from the light source area before capturing test pattern data. This preliminary action allows the system to pre-process and remove brightness unevenness through division calculation, ensuring uniform illumination conditions for accurate test pattern measurement.
Solution Approach 2:
The patent introduces an intermediary processing step that captures brightness distribution information as a separate data element. This intermediary data serves as a mediator to correct the main test pattern capture data through mathematical division, effectively separating the illumination function from the measurement function.
2Manufacturing precision
If filter processing is applied to smooth texture on the print medium, then the brightness unevenness is reduced, but the test pattern details may be blurred
Solution Approach 1:
The patent segments the image processing into two distinct parts: brightness correction processing applied only to the light source area, and unprocessed test pattern data preservation. This segmentation allows selective application of smoothing operations only where needed for illumination correction, without affecting test pattern measurement accuracy.
Solution Approach 2:
The system applies different processing qualities to different regions: the light source area undergoes filter processing for brightness uniformity, while the test pattern area maintains original quality for accurate measurement. This local quality differentiation ensures each region receives appropriate processing without compromising the other.
3Device complexity
If the carriage disposition is restricted, then the structural complexity is reduced, but the light source cannot be optimally positioned for uniform illumination
Solution Approach 1:
The patent replaces mechanical positioning optimization with computational correction. Instead of mechanically adjusting the light source position to achieve uniform illumination, the system uses software-based brightness distribution measurement and division calculation to correct the illumination non-uniformity, substituting mechanical complexity with computational processing.
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 enables the acquisition of accurate test pattern image data despite brightness unevenness, allowing for precise ink ejection timing adjustments even when the print medium has textures, thereby improving printing accuracy.
Implementation Method 1
a light source configured to irradiate a capturing area of the camera with light at a predetermined angle with respect to a print surface of the print medium
Implementation Method 2
a camera configured to capture an image on the print medium
Data Source
AI summary
There is provided a printing apparatus including: an ink jet head that prints on a print medium; a camera that captures an image on the print medium; an LED light source that irradiates a capturing area of the camera with light at a predetermined angle with respect to a print surface of the print medium; a carriage that mounts the ink jet head, the camera, and the LED light source; and a processor that executes calculation based on captured-image-data-of-unprinted-area obtained by capturing an image on the print medium by the camera and captured-image-data-of-test-pattern obtained by capturing an image of a test pattern by the camera, the test pattern being printed on the print medium by the ink jet head, and that acquires corrected captured-image-data representing a captured image of the test pattern, the corrected captured-image-data in which an influence of light irradiation by the LED light source is adjusted.