Multipass Inkjet Density Distribution for Streak Reduction
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Solution Overview
Problem
Inkjet printers face challenges in achieving consistent output density and image quality due to deviations in mechanism control and nozzle characteristics, leading to inconsistencies in ink droplet size and position, which result in noticeable streaks and color banding, especially when using multipass printing with fixed ink types and recording media.
Innovation Solution
The solution involves determining pass distribution coefficients based on the density characteristics of the recording medium and input image data to evenly distribute output density across multiple scans, using a combination of coefficient determination and binary conversion processes to generate image data for each pass, ensuring that the output density is equally divided among passes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multipass printing is performed with fixed ink types and recording media, then printing stability is improved, but output density consistency deteriorates due to mechanical deviations and nozzle variations
Solution Approach 1:
The patent applies dynamics by making the pass distribution coefficients variable rather than fixed. The coefficients are dynamically adjusted based on the specific recording medium type and input image characteristics, allowing the system to adapt to different printing conditions and maintain output density consistency across multiple passes.
Solution Approach 2:
The patent changes the parameters of pass distribution coefficients based on recording medium characteristics and image data. By adjusting these coefficients according to the specific recording medium type and input image properties, the system compensates for mechanical deviations and nozzle variations to maintain consistent output density.
2Reliability
If ink droplet size is increased to cover mechanical deviations, then printing stability is improved, but ink coverage efficiency deteriorates
Solution Approach 1:
The patent segments the printing process into multiple passes with different print duties. Instead of using larger ink droplets in a single pass, the total ink coverage is divided across multiple passes, each contributing a portion of the total density. This segmentation allows smaller, more efficient ink droplets to be used while maintaining overall coverage.
Solution Approach 2:
The patent employs periodic action through multipass printing, where the printing process is repeated multiple times with different pass distribution coefficients. This periodic repetition allows for more uniform ink distribution and better coverage efficiency compared to a single-pass approach with larger droplets.
3Ease of manufacture
If pass distribution coefficients are fixed, then processing simplicity is improved, but output density uniformity deteriorates across different recording media
Solution Approach 1:
The patent changes the pass distribution coefficients based on recording medium characteristics and input image properties. By adjusting these parameters dynamically rather than using fixed values, the system achieves uniform output density across different recording media while maintaining a relatively simple processing framework.
Data Source
AI summary
In a case in which image data used to form an image on a recording medium in a plurality of scans performed across a recording area of the recording medium is generated, a coefficient determination unit determines assignments of output density for the scans on the basis of density characteristics corresponding to the type of recording medium indicated by a recording-medium signal. Multipliers and binary conversion units generate image data for the scans from input image data on the basis of the assignments of the output density.