Inkjet Printing Apparatus Edge Detection and Density Control
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Solution Overview
Problem
Inkjet printing apparatuses face challenges in achieving clear edge portions and high density in printed characters and line drawings due to ink bleed and misalignment issues, particularly when using black ink with low permeation and multi-pass printing with variations in paper feed.
Innovation Solution
The apparatus employs multiple scans using a single or two nozzle arrays per printhead, with varying duty factors for edge and non-edge portions, and uses edge and non-edge detecting processes to generate combined printing data, ensuring high-density, high-quality output by adjusting ink discharge accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the discharge amount of ink droplets is increased to increase the printing density of characters and the like printed in black ink, then the printing density is improved, but the ink can bleed in edge portions of the characters
Solution Approach 1:
The patent applies different ink discharge amounts to different regions of the recording medium. Specifically, the discharge amount is set to a first value for first regions (areas to be printed with black ink) and a second value (different from the first) for second regions (areas to be printed with color ink). This local differentiation allows the edge portions of black ink characters to be printed with reduced ink discharge, preventing bleed, while maintaining high printing density in appropriate areas.
2Quantity of substance
If the discharge amount of ink droplets is increased to increase the printing density of characters and the like, then the printing density is improved, but ink may get mixed with color ink across borders between black and color areas causing bleeding
Solution Approach 1:
The patent differentiates the ink discharge amount based on the specific region being printed. By setting the discharge amount to a first value for black ink regions and a second value for color ink regions, the invention prevents excessive ink discharge at the boundaries between black and color areas, thereby avoiding ink mixing and bleeding while maintaining adequate printing density.
3Manufacturing precision
If the discharge amount of ink droplets is decreased to reduce ink bleed and provide clear edge portions, then edge sharpness is improved, but printing density decreases
Solution Approach 1:
The patent applies different discharge amounts to different regions: a first discharge amount for regions requiring black ink printing and a second discharge amount for regions requiring color ink printing. This localized approach ensures that edge portions and areas prone to bleeding receive reduced ink discharge for sharpness, while other areas receive sufficient ink discharge to maintain high printing density.
Data Source
AI summary
An inkjet printing apparatus includes an edge detecting unit adapted to detect an edge portion and a non-edge portion in the image data; a memory adapted to store a plurality of edge reducing masks used to reduce image data in the edge portion and a plurality of non-edge reducing masks used to reduce image data in the non-edge portion; a reduced data generating unit adapted to generate multiple sets of edge reduced data from image data in the edge portion using the plurality of edge reducing masks and to generate multiple sets of non-edge reduced data from image data in the non-edge portion using the plurality of non-edge reducing masks; and a printing data generating unit adapted to generate multiple sets of printing data by combining the multiple sets of edge reduced data and the multiple sets of non-edge reduced data.