Inkjet Print Ratio Control for Color Unevenness
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Solution Overview
Problem
Bi-directional inkjet printing introduces color unevenness due to reversed ink application orders during forward and backward scans, limiting high-speed output as conventional methods either switch to one-directional printing for areas exceeding a threshold or fail to maintain high-speed bi-directional printing.
Innovation Solution
A data processing method that adjusts the print ratio between forward and backward scans based on multi-value image data, using a print ratio setting unit and print data generation unit to generate binary print data for each scan, allowing for optimized ink application patterns to minimize color unevenness while maintaining high-speed bi-directional printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bi-directional printing is performed to decrease printing time, then productivity is improved, but color unevenness occurs due to reversed ink application orders during forward and backward scans
Solution Approach 1:
The patent applies local quality by determining the print ratio for each pixel individually based on its color characteristics. Pixels are classified into different types (e.g., halftone pixels, solid pixels) and assigned different print ratios dynamically. This allows the system to maintain bi-directional printing for most areas while applying one-directional printing only where necessary to prevent color unevenness, thus resolving the contradiction between printing speed and color uniformity.
Solution Approach 2:
The patent implements dynamics by making the print ratio adjustable and variable rather than fixed. The print ratio setting unit dynamically determines the print ratio for each pixel based on its characteristics and the scan direction. This dynamic adjustment allows the system to optimize between bi-directional printing (for speed) and one-directional printing (for color uniformity) on a per-pixel basis, resolving the contradiction between productivity and manufacturing precision.
2Manufacturing precision
If multi-pass printing is performed to reduce color unevenness, then color uniformity is improved, but printing time increases and productivity decreases
Solution Approach 1:
The patent applies parameter changes by adjusting the print ratio parameter for each pixel based on its characteristics. Instead of uniformly applying multi-pass printing to all pixels (which would increase printing time), the system changes the print ratio parameter dynamically. Halftone pixels receive higher print ratios to ensure color uniformity, while solid pixels maintain lower ratios for speed, thus resolving the contradiction between color uniformity and productivity.
3Manufacturing precision
If one-directional printing is used for areas exceeding a threshold to prevent color unevenness, then color uniformity is improved, but printing time increases and productivity decreases
Solution Approach 1:
The patent applies local quality by treating different pixel types differently based on their characteristics. Instead of applying a uniform printing method to the entire image, the system identifies pixels that are prone to color unevenness (halftone pixels with specific color characteristics) and applies one-directional printing only to those areas. This localized approach prevents color unevenness without unnecessarily increasing printing time for the entire image, thus resolving the contradiction between color uniformity and printing time.
Solution Approach 2:
The patent implements partial action by applying one-directional printing only to the extent necessary - specifically to halftone pixels that are prone to color unevenness, rather than applying it universally. This partial application of the corrective measure (one-directional printing) achieves color uniformity where needed while avoiding the time penalty across the entire image, resolving the contradiction between color uniformity and printing time.
Data Source
AI summary
A data processing apparatus, a data processing method and an inkjet printing apparatus are offered that are capable of reducing, in any kind of image, the occurrence of color unevenness while achieving a high speed output via a bi-directional printing. In order to achieve this, forward scan print ratio and backward scan print ratio with respect to a predetermined area comprising a plurality of pixels is set based on multi-value image data of the predetermined area. Next, binary print data for the forward scans and binary print data for the backward scans at the predetermined area is generated based on the multi-value image data and the set print ratios. According to such a configuration it is possible to increase the ratio of bi-directional printing with respect to areas at which color unevenness appears with difficulty, and increase the ratio of one-directional printing at areas where color unevenness appears with ease.