Ink set
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Solution Overview
Problem
Existing inkjet recording technologies face challenges in achieving good dot expandability and image quality when used in environments with volatile acids, as they often result in ink bleeding and limited print patterns.
Innovation Solution
An ink set comprising a first ink composition with a white pigment and an alkali-soluble resin, a second ink composition with a colored pigment and an amphoteric surfactant, and a pretreatment solution containing an organic acid with a boiling point of 120°C or lower, which enhances abrasion resistance and image quality by stabilizing the ink trajectory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a pretreatment solution containing volatile organic acid is used to achieve good adhesion and laminating strength, then image quality improves, but ink bleeding occurs and dot expandability deteriorates in the printed areas
Solution Approach 1:
The ink set is segmented into multiple ink compositions (first ink composition for white pigment, second ink composition for colored pigment) with different formulations. Each ink composition is optimized for specific functions: the first ink composition uses alkali-soluble resin with high acid value for adhesion, while the second ink composition adds amphoteric surfactant and water-dispersible resin for dot expandability and acid resistance, preventing ink bleeding while maintaining image quality.
Solution Approach 2:
Different regions of the printed material receive different ink compositions with locally optimized properties. The first ink composition provides strong adhesion and acid resistance for the base layer, while the second ink composition provides excellent dot expandability and acid resistance for the colored overlay, allowing each region to perform its specific function optimally.
2Shape
If conventional ink compositions are used to achieve good dot expandability, then printed areas expand properly, but image quality deteriorates in acidic environments
Solution Approach 1:
The ink compositions use parameter changes to achieve both dot expandability and acid resistance. The alkali-soluble resin with acid value of 200 mgKOH/g or higher provides acid resistance, while the amphoteric surfactant and water-dispersible resin in the second ink composition enable good dot expandability. The specific ratios of these components are optimized to balance both properties.
3Strength
If volatile acid is used in pretreatment solution to improve adhesion, then laminating strength increases, but ink trajectory stability deteriorates
Solution Approach 1:
The volatile organic acid in the pretreatment solution, which would normally destabilize ink trajectory, is converted into a benefit through the use of alkali-soluble resin with high acid value in the ink compositions. This resin neutralizes the acid effect, allowing the volatile acid to provide good adhesion and laminating strength without harming ink trajectory stability.
Solution Approach 2:
The alkali-soluble resin with high acid value acts as an intermediary between the volatile organic acid in the pretreatment solution and the ink composition. It neutralizes the acid's harmful effects on ink trajectory while maintaining the adhesion benefits, enabling both laminating strength and trajectory stability to coexist.
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 set achieves excellent abrasion resistance, dot expandability, and image quality even in acidic environments, ensuring stable ink discharge and improved print characteristics.
Implementation Method 1
an alkali-soluble resin having an acid value of 200 mgKOH/g or higher... which stabilizing the ink trajectory
Implementation Method 2
containing an amphoteric surfactant... good dot expandability in the printed areas
Implementation Method 3
containing a water-dispersible resin... excellent abrasion resistance of printed characters and images
Implementation Method 4
a pretreatment solution combined therein that contains an organic acid having a boiling point of 120° C. or lower
Data Source
AI summary
An ink set includes a combination of: a first ink composition containing a white pigment, and an alkali-soluble resin having an acid value of 200 mgKOH/g or higher or a crosslinked product thereof, which accounts for 1.0% by mass or more in the first ink composition, and further containing water; and a second ink composition to be printed over a printing layer constituted by the first ink composition, containing a colored pigment, and an alkali-soluble resin having an acid value of 200 mgKOH/g or higher or a crosslinked product thereof, which accounts for 1.0% by mass or more in the second ink composition, and further containing an amphoteric surfactant, a water-dispersible resin, and water. The ink set is intended to achieve good printability even when a volatile acid is used in a pretreatment solution for the ink set.