Inkjet Nozzle Ejection Control for White Ink Density Uniformity
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Solution Overview
Problem
Image formation devices using a multi-pass method for forming pixel arrays with high-density white ink can result in unevenness in color ink images due to overlapping ink ejection, leading to density inconsistencies.
Innovation Solution
The device includes a control mechanism that adjusts the relative movement of nozzles in the main and sub scan directions to ensure that the total density of color ink ejected onto each pixel array is consistent with the maximum density of the nozzles, using a specific ejection control method to prevent overlapping and maintain even ink distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If white ink is ejected at high density using multi-pass method with overlapping pixel arrays, then white ink density is improved, but color ink image density uniformity deteriorates
Solution Approach 1:
The patent segments the pixel arrays into different types: first pixel arrays scanned an odd number of times, second pixel arrays scanned an even number of times. By controlling color ink ejection differently for each segment based on their scan count parity, the system achieves high white ink density while maintaining color ink uniformity.
Solution Approach 2:
The patent applies different ejection control strategies to different locations in the pixel array based on their scanning characteristics. Color ink nozzles are controlled to eject ink only on specific passes (odd or even scans) depending on the pixel array's position and scan history, creating locally optimized ejection patterns that prevent overlapping color ink deposition.
2Productivity
If multi-pass method is used for high-density white ink printing, then printing productivity is improved, but risk of color ink overlapping increases
Solution Approach 1:
The control portion determines in advance which pixel arrays require color ink ejection based on their scan count and position. By pre-planning the ejection schedule for different nozzle groups (first, second, third nozzles) according to the multi-pass scanning pattern, the system ensures consistent color ink application without overlapping while maintaining high printing speed.
Solution Approach 2:
The patent dynamically adjusts the ejection control strategy based on the actual scanning progress and pixel array characteristics. The control portion modifies ejection commands for different nozzle groups according to whether pixel arrays are being scanned odd or even times, creating a dynamic ejection pattern that adapts to the multi-pass printing process.
Data Source
AI summary
An image formation device includes a plurality of first nozzles which eject a first ink, a plurality of second nozzles which eject a second ink, a processor which forms an image of a resolution R [dpi] on the basis of print data, and a memory which stores computer-readable instructions that, when executed by the processor, perform a process including performing an ejection control, when printing of adjacent D×R pixels is performed by the first ink at a high density Ph [%] that is higher than a unit density Pu [%], such that total densities of the second ink ejected onto each of the pixels in the pixel array by the plurality of times of scanning are, respectively, substantially the same as a maximum density of the second ink able to be ejected at one time from the second nozzles.