Inkjet Dot Grouping for Droplet Interference Control
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Solution Overview
Problem
Inkjet printers face image quality deterioration due to interference between landed ink droplets, where subsequent droplets shift due to surface tension, causing positional shifts and reduced image quality.
Innovation Solution
Classifying dots along the array direction into groups based on ejection time, with a higher ratio of smaller dots in earlier groups, reducing the amount of the first droplet and minimizing interference by controlling the size and position of subsequent dots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ink droplets are ejected in progressively greater quantities to speed up image formation and increase dot density, then productivity is improved, but interference between landed ink droplets occurs causing image quality deterioration
Solution Approach 1:
The patent segments the dot formation process into multiple passes, where dots are formed in different time groups. By controlling the ejection quantity to be smaller in earlier passes and progressively larger in later passes, the system achieves both high productivity and image quality. This segmentation prevents interference between landed droplets while maintaining efficient image formation.
Solution Approach 2:
The patent changes the parameter of droplet ejection quantity over time, specifically making the ejection quantity smaller for earlier time groups and progressively larger for later time groups. This parameter change resolves the contradiction by preventing droplet interference in early passes (when the medium is less saturated) while maximizing productivity in later passes.
2Quantity of substance
If subsequent ink droplets are ejected to increase dot density, then quantity of substance is improved, but positional shift of dots occurs due to surface tension interference
Solution Approach 1:
The patent applies preliminary action by forming dots in a specific sequence with controlled quantities. Earlier dots are formed with smaller quantities to establish a stable base layer that doesn't cause excessive interference. This preliminary formatting of the dot pattern allows subsequent dots to be placed with higher positional accuracy while still achieving the desired dot density.
Solution Approach 2:
The patent uses periodic action by dividing dot formation into multiple time groups with periodic ejection cycles. Each period (time group) has controlled droplet quantities that prevent cumulative interference effects. This periodic control maintains dot position accuracy while progressively building up the required dot density across multiple cycles.
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
This approach minimizes the positional shift of subsequent dots and enhances image quality by reducing the adverse effects of droplet interference, maintaining the integrity of the image formed on the recording medium.
Implementation Method 1
an earlier droplet that has previously landed on a recording medium has not yet been fully absorbed in the recording medium
Implementation Method 2
the liquid inks of the droplets shift toward each other due to their surface tension
Data Source
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AI summary
Ink droplets (150, 152) are ejected from a plurality of dot forming elements (100) arranged along an array direction to form dots (154, 156) of at least two sizes on a recording medium (12). If the dots (154, 156) formed along the array direction are classified into a plurality of groups depending on a plurality of times, the existing ratio of dots (154) of a smaller one of the at least two sizes is higher for one of the groups of an earlier time of the times.