Ink Set Particle Diameter Gradient Suppresses Bleeding
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Solution Overview
Problem
Ink-jet recorded materials using water-based pigment inks experience bleeding when different pigment inks are mixed, leading to unsatisfactory vividness and sharpness, despite adjustments in pigment particle diameters.
Innovation Solution
The solution involves an ink set with pigment inks where the average particle diameter of the first ink is equal to or less than that of the second ink, and at least two inks have different particle diameters, ensuring the second ink's particles do not enter gaps in the first ink, thus suppressing bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the diameter of pigment particles in black ink and color inks are adjusted relative to each other, then bleeding is suppressed, but vividness and sharpness of the recorded material deteriorate
Solution Approach 1:
The patent applies local quality by differentiating pigment particle diameters not just between black and color inks, but within each ink type across multiple particle size ranges. Specifically, it divides pigments into four size categories (0.03-0.15μm, 0.15-0.30μm, 0.30-0.60μm, 0.60-1.20μm) and optimizes the distribution of these sizes locally within each ink formulation to simultaneously achieve bleeding suppression and image quality enhancement
Solution Approach 2:
The patent employs composite materials by formulating each pigment ink as a composite system containing multiple pigment particles with different diameter ranges rather than a single uniform size. This composite approach allows the ink to exhibit both anti-bleeding properties (through smaller particles filling gaps) and high vividness (through larger particles providing color strength)
2Reliability
If pigment inks are used for ink-jet recording, then light fastness and water resistance are improved, but bleeding occurs in boundary portions between color regions
Solution Approach 1:
The patent applies parameter changes by systematically varying the particle diameter parameter of pigments across different ink types and within each ink formulation. By establishing specific particle size ranges (0.03-0.15μm, 0.15-0.30μm, 0.30-0.60μm, 0.60-1.20μm) and their interrelationships, the patent transforms the fixed property of pigment particles into an adjustable parameter set that simultaneously achieves durability and bleeding suppression
Data Source
AI summary
An ink set for ink-jet recording, which provides a vivid and sharp ink-jet recorded material with no bleeding, is composed of a plurality of pigment inks and configured such that the average particle diameter of a pigment contained in any ink precedently landing on a recording medium is less than that of a pigment contained in another ink subsequently landing on the recording medium, and such that at least two pigment inks are different in average particle diameter of the pigment contained therein to each other.