Zigzag Liquid Ejection Head for Streak Suppression
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Solution Overview
Problem
Existing liquid ejection heads face issues with streak generation due to variations in the time difference of liquid droplets landing on a print medium, leading to image quality degradation, especially on lowly-absorbed media.
Innovation Solution
The liquid ejection head is designed with ejection openings arranged in a zigzag pattern, allowing adjacent droplets to land closely and contact each other, reducing time differences and suppressing streak formation, while maintaining high-density printing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ejection openings are arranged in a matrix pattern on the ejection opening surface, then high-density printing is achieved, but the time difference between landing of liquid droplets from adjacent ejection openings becomes large, causing streak generation
Solution Approach 1:
The patent applies asymmetry by changing the ejection opening arrangement from a symmetric matrix pattern to an asymmetric zigzag pattern. In the zigzag arrangement, adjacent ejection openings are positioned at different distances from the print medium, which equalizes the flight time of liquid droplets from different openings. This asymmetric positioning ensures that liquid droplets from all ejection openings reach the print medium at substantially the same time, preventing streak generation while maintaining high printing density.
Solution Approach 2:
The patent transitions from a two-dimensional matrix arrangement to a three-dimensional zigzag arrangement by introducing vertical offset between adjacent ejection openings. The zigzag pattern positions alternate ejection openings at different heights relative to the print medium, creating a three-dimensional configuration that equalizes droplet flight paths. This dimensional change allows high-density arrangement while maintaining uniform landing times across all ejection openings.
2Manufacturing precision
If ejection openings are arranged to reduce landing time variation, then streak generation is suppressed, but the arrangement density of ejection openings must be reduced
Solution Approach 1:
The patent employs dynamics by creating a flexible zigzag arrangement where the vertical offset between adjacent ejection openings can be adjusted based on specific printing requirements. The arrangement allows dynamic optimization of the offset distance to achieve uniform landing times while maximizing ejection opening density. This dynamic configuration enables adaptation to different print media and printing conditions without sacrificing either landing time uniformity or ejection opening density.
3Productivity
If liquid droplets are ejected from adjacent ejection openings at different times, then high-density printing is achieved, but liquid droplets do not contact each other, generating visible gaps as streaks
Solution Approach 1:
The patent applies preliminary action by pre-positioning adjacent ejection openings at calculated vertical offsets before printing begins. This preliminary arrangement ensures that liquid droplets from adjacent openings arrive at the print medium simultaneously, allowing them to contact and merge properly. The pre-calculated zigzag positioning prevents streak formation by ensuring proper temporal and spatial coordination of droplet deposition, eliminating visible gaps between adjacent printed elements.
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 arrangement effectively reduces streaks by ensuring adjacent droplets land and merge on the print medium, enhancing image quality and resolution without increasing the size of the ejection head.
Implementation Method 1
a liquid ejection head that ejects liquids such as ink
Implementation Method 2
the three liquid droplets have landed previously are contracted due to surface tension to be formed as a liquid droplet 134 having a smaller diameter
Implementation Method 3
the liquids ejected from the ejection openings adjacent to each other in the first direction come in contact with each other on the print medium
Data Source
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AI summary
There is provided a liquid ejection head that includes a first ejection opening group (81, 91, 101) in which a plurality of ejection openings that eject a first kind of liquids onto a print medium are arranged in a first direction, and a second ejection opening group (82, 92, 102) that is provided along the first ejection opening group to eject the first kind of liquids onto the print medium. The first ejection opening group is provided upstream of the second ejection opening group in a relative moving direction between the print head and the liquid ejection head, the plurality of ejection openings included in the first ejection opening group are disposed in the first direction in a zigzag shape, and the liquids ejected from the ejection openings adjacent to each other in the first direction come in contact with each other on the print medium.