Ink Formulation for Coated Paper Fixability
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Solution Overview
Problem
Inkjet recording methods face challenges with pigment inks on coated papers due to poor water resistance and light resistance, leading to issues with image density, gloss level, and fixability, as the water-containing organic solvents in these inks permeate slowly and remain on the paper surface, causing driability and transfer problems.
Innovation Solution
An ink formulation containing a wax, specific organic solvents with solubility parameters between 9 and 11 and saturated vapor pressures between 20 mmHg and 400 mmHg at 100°C, which promotes solvent permeation and volatilization, enhancing image density, gloss level, and fixability on both plain and coated papers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pigment inks using water-insoluble pigment are used on coated paper, then water resistance and light resistance are improved, but the water-containing organic solvent permeates slowly and remains on the surface causing poor driability and fixability
Solution Approach 1:
The patent changes the parameters of the organic solvent system by selecting specific solvents with controlled volatility and solubility characteristics. The solvent composition is optimized to achieve appropriate permeation speed through coated paper while maintaining the water-resistant pigment properties, thereby resolving the contradiction between reliability and ease of operation.
Solution Approach 2:
The patent uses a composite ink formulation combining water-insoluble pigment particles with a carefully selected mixture of organic solvents and water-soluble components. This composite approach allows the ink to exhibit both the water resistance of pigments and the controlled permeation characteristics needed for good driability and fixability on coated paper.
2Ease of operation
If dye inks using water-soluble dye are used, then good driability and fixability are achieved, but water resistance and light resistance are poor
Solution Approach 1:
The patent extracts the water-solubility characteristic from the colorant system by using water-insoluble pigments instead of water-soluble dyes. This extraction allows the ink to maintain good permeation and fixability properties while the pigment particles provide inherent water and light resistance, resolving the contradiction between ease of operation and reliability.
3Manufacturing precision
If the water-containing organic solvent permeates slowly through coated paper, then image density and gloss level may be improved, but the solvent remains on the surface causing transfer and scratch issues
Solution Approach 1:
The patent adjusts the volatility parameters of the organic solvent system to achieve optimal evaporation characteristics. The selected solvents have vapor pressures and boiling points that allow sufficient time for permeation and image formation, but then evaporate completely to leave no residual solvent that could cause transfer or scratch problems, thus resolving the contradiction between manufacturing precision and harmful factors.
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 achieves high image density, gloss level, and fixability on coated papers by optimizing solvent properties, ensuring effective spreading and uniform wax distribution, thereby improving image quality and durability.
Implementation Method 1
a speed at which a water-containing organic solvent contained in the inks permeates the coated paper is slow
Implementation Method 2
a compound having a saturated vapor pressure at 100° C. of 20 mmHg or greater but 400 mmHg or less
Data Source
AI summary
Provided is an ink containing a wax, a plurality of organic solvents, and water, wherein the plurality of organic solvents include a compound having a solubility parameter of 9 or greater but 11 or less and a compound having a saturated vapor pressure at 100° C. of 20 mmHg or greater but 400 mmHg or less.