Ink Composition Contact Angle Control for Aggregate Prevention
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Solution Overview
Problem
Continuous supply type ink containers with open atmosphere designs suffer from significant aggregate formation due to a large gas-liquid interface and high contact area with the inner container walls, leading to nozzle clogging and ink supply failures in inkjet recording apparatuses.
Innovation Solution
An ink container design with an ink composition that includes a pigment, organic solvent, and resin, where the static contact angle between the ink and the container walls is set to 10° or more, reducing the formation of a thin ink film and aggregates, and using materials with high liquid repellency to minimize ink attachment and evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a continuous supply type ink container with open atmosphere design is used, then the ink container can be refilled with ink, but aggregates are easily generated at the gas-liquid interface due to evaporation and high contact area with inner walls
Solution Approach 1:
The patent changes the physical-chemical parameters of the ink composition, specifically controlling the surface tension to be 20-50 mN/m and the static contact angle to be 10° or more. These parameter adjustments modify the ink's interaction with the container walls and gas-liquid interface, suppressing aggregate formation while maintaining refillability
Solution Approach 2:
The patent uses a composite ink composition containing pigment, resin, and organic solvent in specific proportions. The resin and organic solvent work together to control surface properties and prevent aggregate formation at the gas-liquid interface and contact portions with inner walls
2Ease of operation
If the wettability of ink to the inner wall material is high, then the ink spreads well, but the area of thin film at contact portion is increased and thickness is reduced, leading to higher aggregate generation
Solution Approach 1:
The patent optimizes the surface tension parameter to 20-50 mN/m and controls the static contact angle to be 10° or more. This creates an optimal balance where the ink has sufficient wettability to flow properly but does not form excessive thin films on the inner walls, thereby reducing aggregate generation
3Reliability
If a filter is provided in the ink supply flow path, then foreign substances are captured, but when a large amount of foreign substances accumulates, the ink supply to the recording head is reduced and normal recording is interrupted
Solution Approach 1:
The patent applies preliminary anti-action by modifying the ink composition to prevent aggregate formation in the first place. By controlling surface tension and contact angle, the ink resists aggregation at the gas-liquid interface and contact portions, reducing the burden on the filter and preventing ink supply interruption
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 solution significantly reduces aggregate formation, enhancing discharge stability and preventing nozzle clogging, thereby ensuring continuous and reliable ink supply to the recording head.
Implementation Method 1
when moisture or the like evaporates from a thin film generated at the gas-liquid interface, the solid content in the ink aggregates to form aggregates
Implementation Method 2
when the wettability of ink to a material constituting the inner wall of the ink chamber is high, the area of a thin film formed at the contact portion of the inner side of the wall and the liquid surface of the ink is increased and the thickness thereof is reduced
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
An ink composition adapted to be poured into an ink container including an ink chamber, the ink chamber partitioned by a wall, refillable with the ink composition via an ink poring port, and communicating with external air, the ink composition comprising a pigment, a resin and an organic solvent, wherein the ink composition has a static contact angle of 10° or more to a member constituting an inner side of the wall.