Ink Set Initiator Segmentation for Gloss and Banding
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Solution Overview
Problem
Conventional ink sets for inkjet recording methods, particularly those using radiation-curable inks, face challenges in achieving excellent glossiness and suppressing banding and hue changes, especially when using magenta and cyan inks which lack thioxanthone-based photopolymerization initiators.
Innovation Solution
The ink set comprises yellow, magenta, cyan, and black ink compositions, each containing a radical polymerizable compound, a radical polymerization initiator including an acylphosphine oxide compound and a thioxanthone compound, with specific mass percentages to enhance glossiness and prevent banding and hue changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thioxanthone-based photopolymerization initiators are used in yellow and black ink compositions, then glossiness is improved, but banding occurrence increases
Solution Approach 1:
The photopolymerization initiator system is segmented into two distinct components: thioxanthone-based initiators (for glossiness) and acylphosphine oxide-based initiators (for preventing banding). Each component is assigned to specific ink compositions based on their functional strengths, creating a divided initiator strategy that resolves the contradiction between glossiness and banding suppression.
Solution Approach 2:
Different initiator compositions are applied locally to different ink types. Yellow and black inks receive thioxanthone-based initiators optimized for glossiness, while cyan and magenta inks receive acylphosphine oxide-based initiators optimized for banding suppression. This localized quality assignment allows each ink to have the optimal initiator composition for its specific requirements.
2Manufacturing precision
If thioxanthone-based photopolymerization initiators are used in magenta and cyan ink compositions, then glossiness is improved, but hue changes occur
Solution Approach 1:
The initiator system is segmented by function and by ink type. Thioxanthone-based initiators are segregated from cyan and magenta inks to prevent hue changes, while acylphosphine oxide-based initiators are assigned to these color-sensitive inks. This segmentation prevents the harmful interaction between thioxanthone and certain colorants while maintaining overall system effectiveness.
Solution Approach 2:
Acylphosphine oxide-based initiators serve as intermediary substances for cyan and magenta inks, providing the necessary photopolymerization function without causing hue changes. These initiators act as a safe intermediary that enables curing in color-sensitive inks where thioxanthone would be harmful.
3Ease of manufacture
If conventional ink compositions are used, then manufacturing cost is reduced, but image quality (glossiness) deteriorates
Solution Approach 1:
The initiator composition parameters are changed from conventional single-initiator systems to optimized dual-initiator systems with specific concentration ranges. Yellow and black inks contain 1-10% thioxanthone-based initiators, while cyan and magenta inks contain 1-10% acylphosphine oxide-based initiators. These parameter changes improve image quality while maintaining manufacturing feasibility through standardized production processes.
Solution Approach 2:
The ink compositions are formulated as composite systems combining multiple components: polymerizable compounds, colorants, and specifically tailored initiator mixtures. Each ink type has a composite composition optimized for its specific requirements, combining the benefits of different initiator types to achieve both cost-effectiveness and high image quality.
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 provides improved glossiness and suppresses banding and hue changes in printed images by optimizing the composition of radical polymerizable compounds and initiators, ensuring better curing properties and image quality.
Implementation Method 1
the respective ink compositions contain a radical polymerizable compound (component A), a radical polymerization initiator (component B)... the component B included in the respective ink compositions contains an acylphosphine oxide compound (component B-1) and a thioxanthone compound (component B-2)
Data Source
AI summary
An ink set including a yellow ink composition, a magenta ink composition, a cyan ink composition, and a black ink composition, in which the respective ink compositions contain a radical polymerizable compound (component A), a radical polymerization initiator (component B), and a colorant (component C) respectively, the component B included in the respective ink compositions contains an acylphosphine oxide compound (component B-1) and a thioxanthone compound (component B-2) respectively, the respective ink compositions contain from 3% by mass to less than 17% by mass of the component B-1, the magenta ink composition and the cyan ink composition contain from 0.1% by mass to less than 2% by mass of the component B-2, and the yellow ink composition and the black ink composition contain from 2% by mass to less than 6% by mass of the component B-2.