Ink Jet Recording Gloss Unevenness Resolution via Ink Composition
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Solution Overview
Problem
Ink jet recording methods face issues with gloss unevenness between black and color regions due to differences in glossiness between black and color inks, particularly high glossiness of black ink leading to unsatisfactory image quality.
Innovation Solution
The method involves using a combination of black ink, mixed color black ink, and color ink with specific pigment ratios and types, including cyan, magenta, and yellow, to adjust the glossiness levels, ensuring the glossiness of the target recording surface is 40 or more at 60°, and using these inks to form images that reduce gloss unevenness by combining them in various patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If black ink with high glossiness is used to form black images, then the black image has high glossiness and good visual appeal, but gloss unevenness occurs between black regions and color regions
Solution Approach 1:
The patent applies local quality by using different ink compositions for different regions: black ink containing black pigment is used specifically for black images where high glossiness is desired, while color inks without black pigment are used for color images. This localized differentiation of ink properties resolves the gloss unevenness problem while maintaining the visual appeal of black regions.
Solution Approach 2:
The patent changes the compositional parameter of the ink by defining specific constraints: black ink must contain black pigment with a concentration of 0.01 to 5 mass%, while color inks must not contain black pigment. This parameter change in ink composition directly controls the glossiness characteristic, allowing black regions to have high gloss while color regions have appropriate gloss levels, thereby eliminating gloss unevenness.
2Illumination intensity
If composite black ink containing both black pigment and color pigment is used, then the black image has adjusted glossiness, but the black tint reproduction and color consistency are compromised
Solution Approach 1:
The patent extracts the black pigment component from the composite ink formulation and places it in a dedicated black ink formulation. By separating the black pigment function from color pigment functions, the patent achieves pure black tint reproduction in black images while allowing color inks to maintain their original color characteristics without contamination from black pigment.
Solution Approach 2:
The patent uses composite material strategy by formulating black ink as a composite containing black pigment (0.01-5 mass%) combined with appropriate binders and solvents. This composite formulation optimizes both the glossiness and black tint reproduction, while color inks use separate composite formulations with color pigments only, ensuring color consistency and preventing gloss unevenness.
Data Source
AI summary
An ink jet recording method using ink selected from a group including (A) black ink containing black pigment, (B) mixed color black ink containing black and color pigments, and (C) color ink containing color pigment, in which an ink glossiness at 60° is increased in the order of black ink (A), mixed color black ink (B), and color ink (C), the target recording surface glossiness at 60° in a target recording medium is 40 or more, and at least one of the following is satisfied: (1) A black image is formed using at least a plurality of types of the color ink of (C) and a color image is formed using the color ink of (C), and (2) A black image is formed using the mixed color black ink of (B) and a color image is formed using the color ink of (C).