Inkjet Maintenance Spit Patterns for Stable Jetting
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Solution Overview
Problem
Existing ink jet imaging devices face issues with jetting stability due to evaporation of ink, leading to print artifacts, as current spit patterns are not sparse enough, exceeding visibility limits and impacting print quality.
Innovation Solution
Implement a spit pattern with clusters of at least two sequential refresh dots from each nozzle, spaced to maximize distance and reduce the frequency of refresh actions, ensuring optimal jet stability with fewer dots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional spit patterns with evenly distributed refresh dots are used, then jetting stability is maintained, but the number of refresh dots is too high causing visibility and print quality issues
Solution Approach 1:
The patent merges multiple refresh dot ejections into clusters, where multiple nozzles eject refresh dots simultaneously at closely spaced time intervals. This clustering approach consolidates the refresh function into concentrated time windows, reducing the overall number of refresh actions needed while maintaining jetting stability through the combined effect of clustered ejections.
Solution Approach 2:
The patent implements periodic clusters of refresh dot ejections rather than continuous or evenly distributed ejections. By organizing refresh actions into periodic clusters separated by longer intervals, the system maintains nozzle stability during active clusters while allowing sufficient rest periods, thereby reducing total refresh dot quantity while preserving jetting reliability.
2Reliability
If refresh dots are ejected frequently to maintain jetting stability, then nozzle performance is preserved, but the spit pattern becomes visible and print quality deteriorates
Solution Approach 1:
By merging refresh dot ejections into clustered patterns from multiple nozzles, the patent concentrates visual impact into brief, localized events that are less perceptible than evenly distributed dots. The clustered approach creates temporal and spatial concentration that reduces overall pattern visibility while maintaining the necessary refresh frequency for jetting stability.
Solution Approach 2:
The periodic clustering of refresh dots creates predictable, rhythmic patterns that are less visually distracting than continuous or random distribution. The longer intervals between clusters allow the human eye to adapt, reducing perceived visibility while ensuring nozzles receive adequate refreshment during each periodic cluster event.
3Object-generated harmful factors
If the number of refresh dots is reduced to improve print quality, then visibility decreases, but jetting stability may be compromised
Solution Approach 1:
The patent compensates for reduced refresh dot frequency by merging ejections into clusters from multiple nozzles. The combined effect of simultaneous clustered ejections provides sufficient ink refreshment to maintain jetting stability even when the overall number and frequency of refresh dots are reduced, thereby preserving print quality.
Solution Approach 2:
The patent uses multiple nozzles to create redundant refresh actions, where each nozzle in the cluster performs a copy of the refresh function. This redundancy ensures that even with fewer total refresh events, the collective action of multiple nozzles maintains adequate ink refreshment and jetting stability across the print head.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method maintains jetting stability with fewer refresh dots, reducing visibility and improving print quality by effectively managing ink evaporation in nozzles.
Implementation Method 1
Due to evaporation of liquids inside or in the vicinity of the nozzle openings through which ink droplets (or any other functional liquid) are expelled, liquid (ink) properties may change
Data Source
AI summary
A method of ink jet printing using an ink jet imaging device including a plurality of nozzles arranged for expelling droplets of an ink by actuation of an ink channel includes the steps of: a) providing a bit map of a spit pattern comprising an arrangement of refresh dots to be printed by each of the plurality of nozzles; and d) printing the bitmap of the spit pattern. The spit pattern includes a plurality of clusters of refresh dots, each cluster including at least two sequential refresh dots expelled from a single nozzle. A spit pattern for use in such a method is disclosed.