Coated Print Medium for Dye-Based Inkjet Optical Density
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Solution Overview
Problem
Inkjet printing with dye-based inks on uncoated paper faces challenges in achieving high optical density and reducing bleed, which affects image quality.
Innovation Solution
A coating formulation comprising a polymeric binder, cationic latex, multivalent cationic salt, and sulfonic acid- or sulfonate-containing stilbene optical brightener is applied to the substrate, enhancing optical density and reducing bleed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a coating is applied to improve optical density, then black optical density increases, but manufacturing complexity increases
Solution Approach 1:
The patent applies composite materials by combining multiple functional components in the coating formulation: polymeric binder for adhesion, cationic latex for ink interaction, multivalent cationic salt for charge balance, and sulfonic acid- or sulfonate-containing stilbene optical brightener for optical enhancement. This composite approach achieves high black optical density while managing the complexity through synergistic material interactions.
Solution Approach 2:
The patent utilizes parameter changes by optimizing the weight percentages of each coating component (polymeric binder: 5-30%, cationic latex: 20-50%, multivalent cationic salt: 5-15%, optical brightener: 1-20%) to achieve the desired optical density. By adjusting these compositional parameters, the coating achieves high black optical density without excessive complexity.
2Manufacturing precision
If a coating is applied to reduce bleed, then black line bleed decreases, but manufacturing complexity increases
Solution Approach 1:
The patent employs composite materials with specific functional assignments: cationic latex (20-50 wt%) interacts with dye-based inks to control bleed through electrostatic interactions, while multivalent cationic salt (5-15 wt%) provides charge balance and enhances ink coating interaction. This composite structure achieves precise bleed control while managing formulation complexity through defined component ratios.
Solution Approach 2:
The coating acts as an intermediary layer between the substrate and the ink, with cationic latex and multivalent cationic salt serving as mediators that control ink penetration and spread. This intermediary function reduces black line bleed by creating a controlled interface that manages ink-substrate interaction without requiring direct ink-substrate contact.
3Illumination intensity
If optical brightener is added to improve optical density, then black optical density increases, but coating formulation complexity increases
Solution Approach 1:
The patent applies parameter changes by optimizing the concentration of sulfonic acid- or sulfonate-containing stilbene optical brightener (1-20 wt%) in the coating formulation. By controlling this parameter within the specified range, the coating achieves enhanced black optical density through optical brightening effects while managing the increase in formulation complexity through defined concentration limits.
Solution Approach 2:
The patent utilizes color changes by incorporating sulfonic acid- or sulfonate-containing stilbene optical brightener, which absorbs UV light and emits blue light to counteract yellowing and enhance the perceived black optical density. This optical brightening mechanism improves black optical density through photoluminescence while adding a specific functional component to the coating formulation.
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 coating formulation significantly improves black optical density and reduces black line bleed, resulting in enhanced image quality for dye-based inkjet inks.
Implementation Method 1
sulfonic acid- or sulfonate-containing stilbene optical brightener
Data Source
AI summary
The present disclosure is drawn to a coated print medium, a method of preparing a print medium, and a printing system. The coated print medium can comprise a substrate and a coating applied to the substrate. The coating can comprise, by solids or dry weight, 5 wt % to 30 wt % of a polymeric binder, 20 wt % to 50 wt % of a cationic latex, 5 wt % to 15 wt % of a multivalent cationic salt, and 1 wt % to 20 wt % of a sulfonic acid- or sulfonate-containing stilbene optical brightener.