Ink Jet Printing Method for Rub Fastness and Cockling Prevention
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Solution Overview
Problem
Aqueous coloring ink compositions used in ink jet printing face challenges with low rub fastness and susceptibility to cockling or curling when applied to paper media, leading to physically weak and easily torn printed items due to high water content and limited solid content for viscosity reduction.
Innovation Solution
An ink jet printing method involving an aqueous coloring ink composition applied to a printing medium with natural and synthetic fibers, combined with a treatment liquid and an aqueous clear ink composition, which includes resin particles and a nitrogen-containing solvent, to enhance rub fastness and image quality while maintaining low volatile organic compound content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an aqueous coloring ink composition is used for printing on a paper medium, then the volatile organic solvent content is reduced, but the printing medium becomes distended and subject to cockling or curling
Solution Approach 1:
The invention changes the chemical composition parameters of the ink by incorporating a fluorinated compound and controlling the content of specific organic solvents. This allows the ink to maintain low VOC content while adjusting its drying characteristics to prevent paper distortion during the printing process
Solution Approach 2:
The invention uses a composite ink formulation combining water, fluorinated compounds, and specific organic solvents in controlled proportions. This composite approach allows the ink to achieve both low environmental impact and appropriate drying behavior that prevents paper cockling and curling
2Ease of operation
If an aqueous coloring ink composition with high water content is used, then the viscosity is reduced for easy ejection, but the printing medium becomes physically weak and easily torn
Solution Approach 1:
The invention carefully controls the water content and organic solvent content within specific ranges (water: 60-80 mass%, organic solvent: 10-30 mass%) to achieve optimal balance between viscosity for ejection and drying speed to prevent paper weakening. The fluorinated compound further modifies the ink's rheological properties
Solution Approach 2:
The fluorinated compound acts as an intermediary substance that modifies the interaction between the ink and paper. It allows the ink to maintain appropriate viscosity for easy ejection while controlling the drying process to minimize water penetration and paper weakening
3Reliability
If the content of solids in aqueous coloring ink composition is increased, then the rub fastness is improved, but the viscosity increases making ejection difficult
Solution Approach 1:
The invention optimizes the solid content within the range of 5-20 mass% and controls the organic solvent content to maintain viscosity below 20 cP at 25°C. This parameter optimization ensures the ink has sufficient solids for good rub fastness while maintaining low viscosity for easy ejection through inkjet nozzles
Solution Approach 2:
The fluorinated compound serves as a mediator that improves the dispersion and distribution of solid particles in the aqueous medium. This allows higher solid content to be achieved without excessive viscosity increase, maintaining both rub fastness and ejection capability
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 method produces printed items with high rub fastness and improved image quality, preventing cockling and maintaining the fibrous texture of the printing medium, suitable for use with aqueous adhesives and suitable for decorative applications like wallpaper.
Implementation Method 1
applying a treatment liquid containing a flocculant capable of forming a floc of at least one constituent of the aqueous coloring ink composition onto the printing surface
Implementation Method 2
an aqueous clear ink composition containing resin particles and a nitrogen-containing solvent
Data Source
AI summary
The ink jet printing method includes applying an aqueous coloring ink composition onto a printing surface of a printing medium by being ejected from an ink jet head. The printing surface of the printing medium contains natural fibers and synthetic fibers.