Ink Composition Surface Tension Control for Multi-Pass Recording
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Solution Overview
Problem
Ink jet recording methods face challenges in achieving high image quality and reducing color differences, particularly when using ink compositions with significant changes in surface tension during evaporation, leading to bleeding and deteriorated print quality.
Innovation Solution
A recording method involving an ink composition with an organic solvent and water, where the absolute difference in surface tension before and after evaporation is minimized to 1 mN/m or less, combined with a treatment liquid containing an aggregating agent, and using a low-absorptive or non-absorptive recording medium, to stabilize ink composition attachment and reduce color variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ink composition is used with significant surface tension change during evaporation, then initial ink ejection is facilitated, but color differences and bleeding occur during multi-pass recording
Solution Approach 1:
The patent applies parameter changes by carefully selecting the surface tension of the ink composition (20-35 mN/m) and the surface tension of the treatment liquid (25-40 mN/m) to ensure that the surface tension difference remains within a specific range (5-15 mN/m) throughout the evaporation process. This controlled parameter adjustment prevents both ejection failures and color differences, resolving the contradiction between ease of operation and manufacturing precision.
2Productivity
If recording medium is heated to accelerate ink drying, then productivity is improved, but ink composition stability deteriorates leading to color variations
Solution Approach 1:
The patent applies beforehand cushioning by pre-heating the recording medium to a controlled temperature (20-60°C) before ink ejection. This prior heating action creates optimal conditions for uniform ink drying during multi-pass recording, preventing composition instability and color variations while maintaining high productivity. The surface tension matching between ink and treatment liquid further cushions against thermal effects.
3Manufacturing precision
If treatment liquid with aggregating agent is applied to improve image quality, then color difference is reduced, but device complexity increases
Solution Approach 1:
The patent applies merging by combining the treatment liquid application process with the existing recording system. The treatment liquid containing the aggregating agent is integrated into the recording apparatus, allowing simultaneous application of treatment liquid and ink composition. This unified approach improves image quality and reduces color differences without significantly increasing device complexity, as the treatment liquid system can share components with the ink ejection system.
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 results in improved image quality, reduced color differences, and enhanced abrasion resistance, while maintaining ejection stability and preventing ink from adhering to the recording head.
Implementation Method 1
heating a recording medium
Implementation Method 2
an absolute value of a difference between a surface tension of the ink composition and a surface tension of the ink composition when the ink composition is evaporated up to an evaporation amount of 0% to 40% by mass
Data Source
AI summary
A recording method includes heating a recording medium and attaching an ink composition including an organic solvent and water to the heated recording medium by performing a main scanning a plurality of times. In each main scanning the ink composition is ejected from a recording head while a position of the recording head relative to the recording medium in a main scanning direction is changed. In the ink composition, an absolute value of a difference between a surface tension of the ink composition and a surface tension of the ink composition when the ink composition is evaporated up to an evaporation amount of 0% to 40% by mass is 1 mN/m or less.