Printing Apparatus Dot Density Control for Color Uniformity
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Solution Overview
Problem
Existing printing technologies fail to adequately address color unevenness between different printing modes due to variations in material, temperature, and humidity, leading to inconsistent image density across areas printed with different techniques.
Innovation Solution
A printing apparatus with a controller that manages the formation of dots on a printing medium using multiple nozzles, adjusting dot density and spacing to match specific printing modes, ensuring consistent image density by generating dot data for areas printed with one or two nozzles, and controlling the printing process to optimize image density based on relative dot diameter and interval ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dots in the second area are formed by two or more nozzles to improve printing coverage, then the image density in the second area increases, but color unevenness occurs between the first area and the second area
Solution Approach 1:
The patent applies different dot formation processes to different areas: the first area uses dots formed by one nozzle while the second area uses dots formed by two or more nozzles. This local differentiation allows each area to be optimized for its specific requirements while the controller coordinates them to achieve overall color uniformity across the entire printing medium.
2Manufacturing precision
If the density of the image in the second area is reduced to inhibit color unevenness, then color uniformity improves, but the printing coverage and image quality in the second area deteriorate
Solution Approach 1:
The controller dynamically adjusts the density parameter of dots in the second area based on the printing mode. When printing in a mode where the second area is formed by two or more nozzles, the controller reduces the dot density in the second area compared to the first area, thereby compensating for the excessive coverage and achieving color uniformity across different areas.
3Manufacturing precision
If different look-up tables are used for color conversion in joint area versus normal area to reduce color unevenness, then color uniformity improves, but the device complexity and processing time increase
Solution Approach 1:
The patent divides the printing area into the first area and the second area, and applies different dot formation processes to each. By segmenting the printing process and using different nozzle configurations for different areas, the patent achieves color uniformity without requiring complex look-up tables for color conversion, thereby reducing device complexity and processing overhead.
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
Effectively reduces color unevenness between areas printed in different modes by adjusting dot formation and density, ensuring consistent image quality regardless of printing conditions.
Implementation Method 1
a printing head having a plurality of nozzles arranged in a first direction, an ink having a specified color being discharged from the nozzles
Implementation Method 2
dots having a specified color being discharged from the nozzles; a head driver configured to drive the printing head to form a plurality of dots
Data Source
AI summary
A printing apparatus includes a print execution section and a controller. The print execution section includes: a printing head having nozzles arranged in a first direction; a head driver that drives the printing head to discharge ink from the nozzles thereby forming dots on a printing medium; and a movement mechanism that moves the printing medium relative to the printing head in any of the first direction and a second direction intersecting with the first direction. The controller obtains a piece of object image data, generates, by using the object image data, a plurality of pieces of dot data indicating formation states of the dots for pixels, and prints a printing image by causing the print execution section to execute discharge of the ink and movement of the printing medium by use of the pieces of dot data.