Printer Ink Discharge Control Using Test Pattern Imaging
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Solution Overview
Problem
Printing apparatuses face challenges in maintaining high-quality image formation across various media due to limitations in ink discharge control, leading to issues like bleeding and unevenness, especially when encountering unknown media types.
Innovation Solution
A printing apparatus that captures images of a test pattern and adjusts droplet discharge based on grayscale values of the pattern's edge and central regions, using an evaluation index to set a limit value for ink discharge, ensuring optimal image quality regardless of the medium type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a limit value of ink discharge amount is set in advance in a color variable table, then printing quality is maintained for predetermined media, but the apparatus cannot handle unknown media types effectively
Solution Approach 1:
The system performs preliminary printing of a test pattern on the actual medium before the main printing operation. This preliminary action allows the apparatus to characterize the specific medium's properties (absorption, texture, density) and determine appropriate discharge amount limits tailored to that medium, rather than relying on pre-stored values for predetermined media types only.
Solution Approach 2:
The imaging device captures an image of the printed test pattern, and the control unit analyzes the captured image to evaluate density distribution. This feedback loop allows the system to measure the actual printing results on the specific medium, calculate appropriate discharge amount limits based on observed density values, and adjust subsequent printing parameters accordingly, enabling adaptation to unknown media types.
2Quantity of substance
If the ink discharge amount is increased to expand color reproduction range, then image density and vividness improve, but bleeding and unevenness occur degrading printing quality
Solution Approach 1:
Instead of using a fixed discharge amount limit for all media, the system dynamically determines the appropriate limit by actually printing a test pattern on the specific medium, capturing its image, and analyzing the density distribution. This dynamic adjustment allows the apparatus to optimize the discharge amount for each medium type, maximizing color reproduction while preventing bleeding and unevenness specific to that medium's properties.
Solution Approach 2:
The control unit calculates discharge amount limits based on measured density values from the captured test pattern image. By changing the discharge amount parameter according to the actual medium characteristics observed in the captured image, the system achieves optimal balance between ink quantity for color reproduction and precision for preventing quality degradation.
3Manufacturing precision
If the ink discharge amount is limited to prevent bleeding, then printing quality is maintained, but the color reproduction range is narrowed
Solution Approach 1:
The system performs preliminary printing of a test pattern with relatively high ink discharge to fully utilize the medium's absorption capacity. By evaluating the density distribution of this preliminary print, the system determines the maximum safe discharge amount for that specific medium, thereby expanding the color reproduction range while maintaining printing quality.
Solution Approach 2:
The imaging device captures the test pattern to provide feedback on actual printing performance. The control unit uses this feedback to calculate the optimal discharge amount limit specific to the medium's properties, allowing the system to maintain printing quality while maximizing ink utilization and color reproduction range for each medium type.
Data Source
AI summary
There is provided a printer including an imaging device that captures an image of a medium, and a control unit that controls an ink discharge amount of a printing unit that discharges ink to form an image. The control unit acquires a captured image of a test pattern which is obtained by an imaging device and is printed by the printing unit, and controls an ink discharge amount on the basis of a grayscale value of a first region including an outer peripheral edge of the test pattern and a grayscale value of a second region within the test pattern.