Liquid Ejection Head Droplet Timing Control for Image Quality
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Solution Overview
Problem
In liquid ejection apparatuses with multiple ejection openings per channel, the varying directions of ejected droplets lead to poor image quality due to differences in droplet flight paths.
Innovation Solution
A liquid ejection apparatus with a controller that uses multiple drive signals with different ejection periods to control the energy application in pressure chambers, ensuring that droplets from multiple ejection openings form a single pixel, thereby aligning and stabilizing the droplet paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple ejection openings are disposed per channel to increase productivity, then the number of ejected droplets increases, but the droplets fly in different directions causing image quality degradation
Solution Approach 1:
The patent applies dynamics by varying the ejection period of droplets from different ejection openings. Instead of ejecting all droplets simultaneously, the controller adjusts the timing of ejection for each opening dynamically, causing droplets to be ejected at different times rather than in the same direction simultaneously. This temporal differentiation resolves the contradiction by maintaining multiple ejection openings for productivity while preventing directional conflicts that degrade image quality.
2Productivity
If droplets are ejected simultaneously from multiple ejection openings to form one pixel, then productivity increases, but droplet direction differences cause poor image quality
Solution Approach 1:
The patent implements periodic action by using different ejection periods for droplets from different ejection openings. The controller sets specific time intervals between ejections from each opening, creating a periodic ejection pattern rather than simultaneous ejection. This ensures that droplets are deposited sequentially at the same pixel location with precise timing control, maintaining both productivity through multiple openings and precision through controlled periodic ejection.
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 effectively reduces image quality degradation caused by droplet misalignment, resulting in improved image formation and recording precision.
Implementation Method 1
an energy-applying portion configured to apply energy to liquid in the plurality of pressure chambers such that the liquid droplets are ejected from at least one ejection opening group
Data Source
AI summary
A liquid ejection apparatus includes a liquid ejection head including a plurality of ejection opening groups each constituted by two or more ejection openings and each forming one pixel by at least two liquid droplets ejected from the two or more ejection openings of a corresponding one of the plurality of ejection opening groups; a plurality of individual channels respectively connecting the plurality of ejection opening groups to a plurality of pressure chambers; and an energy-applying portion applying energy to liquid in the plurality of pressure chambers, and a controller controlling the energy-applying portion. The controller controls the energy-applying portion to form one pixel by using at least a first drive signal whose ejection period is a first ejection period and a second drive signal whose ejection period is a second ejection period different from the first ejection period.