Printing Apparatus Brightness Unevenness Control
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Solution Overview
Problem
Existing printing technologies face issues with acquiring high-quality image data due to brightness unevenness caused by variations in print medium and ink types, which affects the accuracy of reflectance characteristics and density unevenness detection.
Innovation Solution
A printing apparatus and method that includes a transport mechanism, print head, camera, light source, and processor to capture and analyze test patterns, determining a specific range for reflectance within a predetermined range, allowing for the acquisition of high-quality image data by adjusting the transport range and processing multiple images to synthesize captured data, and adjusting ink ejection based on detected density unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light irradiation is used to capture test pattern images, then image capture is enabled, but brightness unevenness occurs due to directional characteristics of reflected light varying with print medium and ink types
Solution Approach 1:
The patent applies preliminary action by measuring reflectance characteristics before capturing the test pattern image. The processor first acquires reflectance characteristic data representing the reflectance characteristics of the print medium and ink under the light source, then uses this data to determine the specific range where reflectance is within a predetermined range before capturing the image. This preliminary measurement and range determination eliminates brightness unevenness caused by directional characteristics of reflected light.
Solution Approach 2:
The patent applies parameter changes by adjusting the capturing range based on reflectance characteristics. The processor determines a specific range in the transport direction where the reflectance is within a predetermined range, and captures the test pattern image only within this specific range. By changing the capturing parameters based on measured reflectance characteristics, the system eliminates brightness unevenness while maintaining image quality.
2Loss of information
If the capturing range is extended to cover the entire test pattern, then complete image data is acquired, but brightness unevenness affects the accuracy of reflectance characteristics
Solution Approach 1:
The patent applies local quality by capturing the test pattern image only within a specific range where reflectance characteristics are appropriate, rather than capturing the entire test pattern. The processor determines a specific range in the transport direction where reflectance is within a predetermined range, and captures images only within this range. This localized capturing approach ensures high measurement precision while acquiring sufficient image data for accurate reflectance characteristic determination.
3Measurement precision
If multiple images are captured and synthesized to improve image quality, then image quality increases, but processing time increases
Solution Approach 1:
The patent applies preliminary action by determining the specific capturing range before actual image capture. The processor first acquires reflectance characteristic data and determines the specific range where reflectance is within a predetermined range. This preliminary determination ensures that subsequent image captures are performed only within the optimal range, eliminating the need for extensive processing of out-of-range areas and reducing overall processing time while maintaining high image quality.
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 effectively suppresses brightness unevenness and detects density unevenness with high accuracy, ensuring high-quality image data and improved printing performance regardless of print medium or ink type.
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
Data Source
AI summary
There is provided a printing apparatus including: a transport mechanism; an ink jet head; a camera; a 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 includes the ink jet head, the camera, and the light source; and a controller (processor) that acquires reflectance characteristic data of irradiation light from the light source based on a captured image obtained by capturing an image of a printed test pattern by the camera, determines a specific initial-and-final-image-data range or a specific acquisition range in which the reflectance is within a specific reflectance range based on the acquired reflectance characteristic data, and acquires captured image data corresponding to the specific initial-and-final-image-data range or the specific acquisition range.