Ink and Reaction Liquid Set for High-Speed Inkjet Printing
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Solution Overview
Problem
Ink jet recording methods face challenges in achieving high-speed recording while maintaining excellent optical density and image fixability, as existing techniques either result in prolonged drying times or lead to sticking issues on the recording head's ejection orifice surface due to enhanced reactivity between the ink and reaction liquid.
Innovation Solution
A set comprising an ink and a reaction liquid, where the ink contains a resin-dispersed pigment and a polyvalent metal ion, and the reaction liquid includes a nonionic surfactant, which controls the reactivity to achieve high optical density and fixability without using a reaction inhibitor, thereby suppressing sticking on the recording head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the penetration and diffusion of ink into the recording medium are inhibited to achieve high optical density, then the optical density is improved, but the drying time is prolonged and image fixability is not achieved
Solution Approach 1:
The invention changes the chemical parameters of the ink by adding a polyvalent metal ion to react with the anionic surfactant in the reaction liquid, forming an insoluble precipitate that rapidly fixes the ink on the recording medium. This chemical reaction parameter change enables simultaneous achievement of high optical density and rapid drying, resolving the contradiction between improving optical density and reducing drying time
Solution Approach 2:
The polyvalent metal ion acts as an intermediary substance that facilitates the reaction between the ink and reaction liquid. It forms an insoluble precipitate that serves as a bridge to rapidly fix the ink on the recording medium, enabling both high optical density and quick drying without requiring the ink to penetrate and diffuse slowly into the medium
2Manufacturing precision
If the reactivity between ink and reaction liquid is enhanced to achieve high optical density, then the optical density is improved, but sticking occurs on the ejection orifice surface of the recording head
Solution Approach 1:
The invention applies local quality by using a nonionic surfactant specifically in the reaction liquid that will be ejected onto the recording head surface, while the ink contains a polyvalent metal ion. The nonionic surfactant provides local protection on the ejection orifice surface by reducing surface tension and preventing the formation of insoluble precipitates in this specific location, thus suppressing sticking while allowing high reactivity elsewhere to achieve high optical density
3Object-generated harmful factors
If a reaction inhibitor is added to suppress sticking on the recording head, then sticking is suppressed, but the reactivity between ink and reaction liquid is reduced and optical density deteriorates
Solution Approach 1:
The nonionic surfactant serves as a specialized intermediary that performs the dual function of preventing sticking on the recording head while not interfering with the beneficial reaction between ink and reaction liquid on the recording medium. It mediates the surface properties of the ejection orifice without acting as a general reaction inhibitor, thus maintaining high optical density while suppressing sticking
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 enables high-speed recording with excellent image fixability and optical density while preventing sticking on the recording head's ejection orifice surface, optimizing the interaction between the ink and reaction liquid to ensure effective image formation.
Implementation Method 1
the reaction liquid includes a nonionic surfactant, which controls the reactivity to achieve high optical density and fixability without using a reaction inhibitor, thereby suppressing sticking on the recording head
Implementation Method 2
the ink contains a resin-dispersed pigment and a polyvalent metal ion, and the reaction liquid includes a nonionic surfactant
Data Source
AI summary
A set of an ink containing a pigment dispersed by a water-soluble resin and having the surface tension of 38 mN/m or less and a reaction liquid containing a polyvalent metal ion and a surfactant, which is an ethylene oxide adduct of a higher alcohol of a linear primary or secondary alcohol or an isoalkyl alcohol, and has a HLB value of 13.0 or more as determined by the Griffin method. The content of the polyvalent metal ion in the reaction liquid is 10.0 times or more in terms of molar ratio as much as an amount of an acidic group derived from the water-soluble resin in the ink and the content of the surfactant in the reaction liquid is 0.15 times or more in terms of mass ratio as much as the total content of the pigment and water-soluble resin in the ink.