Ink Composition with Low SP Solvents for Curling Suppression
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Solution Overview
Problem
Existing inkjet recording technologies face challenges with curling of prints and deterioration of liquid repellency in inkjet head members, particularly when using inks with low-polarity solvents, which affect discharge reliability and image quality.
Innovation Solution
An inkjet ink composition comprising water-soluble organic solvents with a solubility parameter of 27.5 or less, colloidal silica, and a pH range of 7.5 to 10, along with a specific formulation of water-soluble organic solvents and colloidal silica content, to enhance discharge reliability and prevent curling and liquid repellency deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an aqueous ink including a low-polarity solvent at a content of 30% by mass or more is used to suppress curling, then curling is alleviated, but liquid repellency of the inkjet head deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the solubility parameter (SP value) of water-soluble organic solvents to be 27.5 or less, and setting their content to 5-30% by mass. This specific parameter range modifies the ink's interaction with the recording medium to suppress curling while maintaining liquid repellency. The patent also controls pH (7.5-10) and includes colloidal silica (0.005-0.5% by mass) to further optimize these parameters.
Solution Approach 2:
The patent uses composite materials by combining multiple water-soluble organic solvents with different SP values (all ≤27.5), colloidal silica particles, and colorants in specific proportions. This composite formulation creates an ink composition that achieves curling suppression through the collective effect of low-SP solvents and colloidal silica, while the specific composition ratios prevent liquid repellency deterioration.
2Manufacturing precision
If colloidal silica is added to form favorable images, then image quality improves, but discharge reliability may be affected
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size of colloidal silica (volume average diameter of 25 nm or less) and its content (0.005-0.5% by mass). This specific parameter range allows colloidal silica to improve image quality through controlled deposition and reduced curling, while the low concentration and small particle size prevent discharge reliability issues.
3Manufacturing precision
If a large amount of ink is applied to achieve good image coverage, then image quality improves, but curling of the recording medium worsens
Solution Approach 1:
The patent applies parameter changes by using water-soluble organic solvents with SP values of 27.5 or less, which have specific wetting and drying characteristics. These solvents allow the ink to be applied in sufficient amounts for good image coverage while controlling the drying process to minimize curling. The low SP value ensures proper interaction with the recording medium surface.
Solution Approach 2:
The patent uses colloidal silica as an intermediary substance that mediates between the ink and recording medium. The colloidal silica particles (≤25 nm diameter) at 0.005-0.5% content act as a buffer that reduces the direct impact of large ink volumes on the recording medium, thereby preventing excessive curling while maintaining image coverage.
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 inkjet ink composition effectively suppresses curling of prints and deterioration of liquid repellency in inkjet head members, ensuring reliable ink discharge and maintaining image quality.
Implementation Method 1
an inkjet ink composition including at least one water-soluble organic solvent, water, at least one colorant, and at least one colloidal silica, wherein 40% or more by mass of a total content of the water-soluble organic solvent has an SP value of 27.5 or less, and the inkjet ink composition having excellent discharge reliability, and suppressing curling of prints formed with the ink
Implementation Method 2
40% or more by mass of a total content of the water-soluble organic solvent has an SP value of 27.5 or less
Implementation Method 3
suppressing curling of prints formed with the ink and deterioration of liquid repellency of an inkjet head member
Data Source
AI summary
The present invention provides an inkjet ink composition including at least one water-soluble organic solvent, water, at least one colorant, and at least one colloidal silica, wherein 40% or more by mass of a total content of the water-soluble organic solvent has an SP value of 27.5 or less, and the inkjet ink composition having excellent discharge reliability, and suppressing curling of prints formed with the ink and deterioration of liquid repellency of an inkjet head member.