Printing Apparatus Controller Adjusting Dot Data Density for Color Uniformity
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Solution Overview
Problem
Existing printing technologies face challenges in reducing color unevenness between different areas of a printed image, particularly due to variations in printing medium material, temperature, and humidity, leading to noticeable color irregularities.
Innovation Solution
A printing apparatus with a controller that generates dot data for specific color pixels, using multiple nozzles for some areas and single nozzles for others, and adjusts the density of the image in overlap areas to match non-overlap areas, ensuring consistent color output by determining a correction level based on image data from both areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple nozzles are used to print in overlap areas (second area), then printing coverage is improved, but color unevenness occurs due to density differences compared to single-nozzle areas
Solution Approach 1:
The patent applies different printing processes to different areas: single-nozzle printing for non-overlap areas and multi-nozzle printing for overlap areas. This local differentiation allows each area to be optimized for its specific characteristics, resolving the color unevenness issue while maintaining comprehensive coverage
Solution Approach 2:
The patent changes the nozzle configuration parameter based on location: using one nozzle for raster lines in non-overlap areas and two or more nozzles for raster lines in overlap areas. This parameter adjustment ensures consistent image density and color uniformity across the entire printing surface
2Manufacturing precision
If different look-up tables are used for color conversion in joint areas versus ordinary areas, then color unevenness is reduced, but device complexity increases
Solution Approach 1:
The patent segments the printing area into non-overlap areas and overlap areas, and applies different dot data generation processes to each segment. This segmentation approach enables precise color control in each area while maintaining overall system manageability
Solution Approach 2:
The patent performs preliminary classification of raster lines into those requiring single-nozzle printing and those requiring multi-nozzle printing before the actual printing process. This advance preparation simplifies the overall control logic by pre-determining the printing parameters for each area
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, an ink having a specified color being discharged from the nozzles; a head driver which drives the printing head to form dots having the specified color on a printing medium by discharging the ink having the specified color from the nozzles; and a movement mechanism which moves the printing medium relative to the printing head. The controller is configured to: obtain object image data; generate, by using the object image data, a plurality of pieces of dot data indicating formation states of the dots having the specified color, for a plurality of pixels; and print a printing image by causing the print execution section to execute discharge of the ink having the specified color and movement of the printing medium by use of the pieces of dot data.