Ink Set Dynamic Surface Tension Control Bleeding
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Solution Overview
Problem
Current ink jet recording methods fail to achieve high optical density and bleeding resistance while maintaining fixability, particularly in high-speed printing applications, due to limitations in controlling dynamic surface tension and ink interactions.
Innovation Solution
An ink set comprising a first ink with a coloring material, a fluorinated surfactant, and a specific salt, where the dynamic surface tension at 50 msec is high to prevent bleeding and gradually lowers at 5000 msec to enhance fixability, using a combination of polyoxyethylene alkyl ether and fluorinated surfactant interactions to control surface tension effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the viscosity of ink is increased to reduce bleeding, then bleeding resistance is improved, but ejection stability deteriorates and drying properties worsen
Solution Approach 1:
The patent changes the surface tension parameter of the ink by incorporating fluorinated surfactants. This allows the ink to maintain lower viscosity for stable ejection while achieving high bleeding resistance through controlled surface tension properties that prevent ink spreading on the recording medium.
Solution Approach 2:
The fluorinated surfactant acts as an intermediary substance that mediates between the conflicting requirements. It modifies the ink's interaction with the recording medium to prevent bleeding without requiring increased viscosity, thus maintaining ejection stability while achieving the desired bleeding resistance.
2Duration of action of moving object
If the surface tension of ink is decreased to improve drying properties, then drying speed is improved, but optical density deteriorates
Solution Approach 1:
The patent employs dynamic surface tension control where the surface tension is high initially to ensure proper ink aggregation and optical density, then gradually decreases to enable rapid drying. This dynamic adjustment allows both high optical density and fast drying speed to be achieved simultaneously.
Solution Approach 2:
The fluorinated surfactant enables dynamic surface tension adjustment throughout the ink drying process. The surface tension is maintained at appropriate levels during ink deposition for high optical density, then naturally decreases to accelerate drying, resolving the contradiction between these two opposing requirements.
3Reliability
If fluorinated surfactant is incorporated into ink to reduce solidification in recording head, then ejection stability is improved, but bleeding resistance deteriorates
Solution Approach 1:
The patent precisely controls the concentration and type of fluorinated surfactant to achieve the optimal balance. By adjusting the surfactant parameters, the ink maintains low enough surface tension for stable ejection and reduced solidification in the recording head, while simultaneously achieving sufficient bleeding resistance through controlled interaction with the recording medium.
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 ink set achieves improved optical density, bleeding resistance, and fixability by maintaining high initial surface tension for ink aggregation and rapid absorption, ensuring high-speed printing with reduced ink detachment and bleeding.
Implementation Method 1
the difference between the dynamic surface tensions of the first ink at lifetimes of 50 msec and 5000 msec measured by a maximum bubble pressure method at 25° C. is 17 mN/m or more, and the dynamic surface tension of the first ink at a lifetime of 5000 msec is 32 mN/m or less
Data Source
AI summary
An ink set for an aqueous ink jet includes a first ink and a second ink, in which the first ink satisfies requirement 1 and requirement 2 described below:requirement 1: the first ink contains a coloring material, a fluorinated surfactant, and a specific salt, andrequirement 2: the difference between the dynamic surface tensions of the first ink at lifetimes of 50 msec and 5000 msec measured by a maximum bubble pressure method at 25° C. is 17 mN/m or more, and the dynamic surface tension of the first ink at a lifetime of 5000 msec is 32 mN/m or less.