Ink Receiving Layer Silica Binder Ratio for Optical Density

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Solution Overview

Problem

Current recording media with matted surfaces using aqueous pigment inks struggle to achieve high optical density in printed images, as existing solutions do not adequately balance binder and amorphous silica ratios, leading to insufficient image development and fixability issues.

Innovation Solution

A recording medium with an ink receiving layer containing amorphous silica and a binder, where the peak area ratio of carbon to silicon atoms measured by X-ray photoelectron spectroscopy is between 0.7 and 2.3, and a contact angle of 60° or less after 10 ms, ensuring optimal binder distribution and ink fixability, along with a surfactant to enhance wet-spread and uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a pigment particle with large secondary particle size is contained in the surface layer to decrease the degree of gloss, then the matted surface quality is improved, but the optical density of the image printed by aqueous pigment ink is insufficient

Engineering Contradiction:
Improvesurface qualityVSAvoidoptical density
Core Design Contradiction:
ShapeVSIllumination intensity

Solution Approach 1:

The invention applies local quality by creating distinct functional zones within the ink receiving layer: the surface portion contains pigment particles for matting effect, while the lower portion contains binder and amorphous silica for ink absorption and fixation. This spatial differentiation allows simultaneous achievement of matted surface quality and high optical density.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention uses composite materials by combining binder and amorphous silica in the lower portion of the ink receiving layer. The amorphous silica with specific surface area of 50-200 m²/g provides optimal ink absorption and fixation properties, while the binder ensures proper adhesion. This composite structure enables both matting and high optical density.

Inventive Principle:
Principle #40Composite materials

2Shape

If the ratio of binder to amorphous silica is not optimized, then the surface may achieve matted appearance, but the ink fixability and image development are insufficient

Engineering Contradiction:
Improvematted appearanceVSAvoidink fixability
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The invention applies parameter changes by optimizing the surface area of amorphous silica to 50-200 m²/g and controlling the binder-to-silica mass ratio in the lower portion to 1:4 to 1:1. These specific parameter ranges ensure optimal ink absorption kinetics and fixation reliability, preventing both rapid solvent absorption and insufficient image development.

Inventive Principle:
Principle #35Parameter changes

3Shape

If the binder distribution is uneven, then the matted surface may be achieved, but cracks occur and image uniformity deteriorates

Engineering Contradiction:
Improvematted surfaceVSAvoidimage uniformity
Core Design Contradiction:
ShapeVSStability of the object's composition

Solution Approach 1:

The invention applies local quality by concentrating the binder in the lower portion of the ink receiving layer rather than distributing it uniformly throughout. This localized binder placement provides structural support and prevents cracking while allowing the surface portion to maintain matted appearance with pigment particles.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention uses composite materials combining binder and amorphous silica in the lower portion with controlled mass ratios. This composite structure provides both mechanical integrity (preventing cracks) and controlled ink fixation, ensuring image uniformity while maintaining matted surface quality.

Inventive Principle:
Principle #40Composite materials

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 solution allows for high optical density and improved color development properties in pigment ink printing by ensuring proper binder distribution and ink fixation on the amorphous silica surface, preventing cracks and rapid solvent absorption, thus enhancing image quality.

Implementation Method 1

an ink receiving layer containing amorphous silica and a binder, on a substrate

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

ensuring proper binder distribution and ink fixation on the amorphous silica surface

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

along with a surfactant to enhance wet-spread and uniformity

Methodology Applied
Scientific EffectSurfactant: Surfactant

Implementation Method 4

preventing cracks and rapid solvent absorption

Methodology Applied
Scientific EffectHydrophobe: Hydrophobe

Data Source

PatentEP3189975B1Recording medium
Publication Date: 2020.08.26 CANON KK

AI summary

An inkjet recording medium including a substrate and an ink receiving layer on the substrate, wherein the ink receiving layer includes amorphous silica having an average secondary particle size of 3 µm or more, and a binder, the peak area ratio (C1s/Si2p) of a carbon atom (C1s) to a silicon atom (Si2p) in measurement of the surface of the ink receiving layer by X-ray photoelectron spectroscopy is 0.7 or more and 2.3 or less, and the contact angle between the surface of the ink receiving layer and pure water after a lapse of 10 ms from contact of the surface of the ink receiving layer with 4 µl of pure water is 60° or less.