Nozzle Row Ink Limits for Color Uniformity
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Solution Overview
Problem
Inkjet printers face color irregularities due to varying distances between nozzle rows for different colors in the relative movement direction, leading to streaks and color inconsistencies in the printing process.
Innovation Solution
A printing apparatus and method where the recording head has multiple nozzle rows for different colors, with fixed distances between specific combinations of nozzle rows to manage ink droplet discharge and upper limits, ensuring consistent ink distribution and reduced color irregularity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple nozzle rows for different colors are arranged in the recording head, then color printing capability is improved, but color irregularity and streaks occur due to varying distances between nozzle rows
Solution Approach 1:
The patent applies local quality by setting different amount-of-ink upper limits for different color combinations based on their specific distance relationships. Specifically, combinations with multiple possible distances (e.g., C and Y) have lower ink limits, while combinations with fixed distances (e.g., C and M) have higher ink limits, allowing each color pair to be optimized for its geometric characteristics
Solution Approach 2:
The patent changes the parameter of ink discharge amount by implementing different amount-of-ink upper limits for different color combinations. This parameter adjustment compensates for the geometric irregularities in nozzle row arrangements, preventing color irregularity and streaks while maintaining full-color printing capability
2Length of moving object
If the number of nozzle rows in transportation direction is decreased, then head length is reduced, but distance between nozzle rows for different colors varies causing color irregularity
Solution Approach 1:
The patent resolves this contradiction by changing the ink discharge parameter - setting lower amount-of-ink upper limits for color combinations with variable distances. This allows the use of fewer nozzle rows (shorter head) while compensating for the resulting distance variations through controlled ink reduction, preventing color irregularity
3Productivity
If amount of ink discharged per unit area is increased, then printing speed is improved, but color irregularity and streaks become more prominent
Solution Approach 1:
The patent optimizes the ink discharge parameter by implementing color-combination-specific upper limits. This allows higher overall ink discharge rates (maintaining printing speed) while applying conservative limits only to problematic color combinations, preventing color irregularity without sacrificing productivity
Data Source
AI summary
A recording head has two or more first nozzle rows from which an ink droplet of a first color is discharged, two or more second nozzle rows from which an ink droplet of a second color is discharged, and two or more third nozzle rows from which an ink droplet of a third color is discharged. In a plurality of nozzle rows from which an ink droplet is discharged on the same line along the relative movement direction, a distance between the first nozzle row and the second nozzle row in the relative movement direction is fixed, and a plurality of distances are present regarding a distance between the first nozzle row and the third nozzle row in the relative movement direction. Concerning an amount-of-ink upper limit that is an upper limit of an amount of ink that is dischargeable per unit area of the print substrate, first printing in which an amount-of-ink upper limit for a combination of the first nozzle row and the third nozzle row is smaller than an amount-of-ink upper limit for a combination of the first nozzle row and the second nozzle row is performed.