Recording Medium Surface Roughness Control for High Optical Concentration

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Solution Overview

Problem

Existing recording media with matte tones struggle to achieve high optical concentration when using water-based dye ink, particularly in maintaining the unevenness of the base material and reducing irregularities during inkjet printing.

Innovation Solution

A recording medium with an absorbent substrate and an ink receiving layer containing inorganic particles and a binder, where the arithmetic average roughness and average length of the substrate and ink receiving layer surfaces are specifically controlled to ensure uniform image recording with high optical concentration, even with water-based dye ink.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If an inorganic particle with large secondary particle diameters is used to obtain recording media with reduced glossiness and matte tones, then the matte tone is improved, but the optical concentration of recorded images deteriorates

Engineering Contradiction:
Improvematte toneVSAvoidoptical concentration
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The invention changes the surface roughness parameters by controlling the arithmetic average roughness Ra1 of the absorbent substrate to be 5.0 μm or more, and by controlling the ratio Ra2/Ra1 and RSm2/RSm1 to fall within specific ranges. This parameter optimization allows the matte surface to maintain high optical concentration when used with water-based dye ink, resolving the contradiction between matte tone and image quality.

Inventive Principle:
Principle #35Parameter changes

2Shape

If the surface roughness of the absorbent substrate is increased to maintain the feeling of unevenness, then the base material unevenness is improved, but the irregularities in recorded images increase

Engineering Contradiction:
Improvebase material unevennessVSAvoidimage uniformity
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The invention optimizes the surface roughness parameters by setting Ra1 ≥ 5.0 μm while controlling the ratios Ra2/Ra1 ≥ 0.87 and RSm2/RSm1 ≤ 1.40. This coordinated parameter control ensures that the base material maintains its unevenness feeling while the ink receiving layer compensates to prevent image irregularities, achieving both aesthetic and quality requirements.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If water-based dye ink is used to achieve good color development, then the ink compatibility is improved, but the optical concentration of recorded images deteriorates

Engineering Contradiction:
Improveink compatibilityVSAvoidoptical concentration
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The invention optimizes the surface roughness parameters (Ra1 ≥ 5.0 μm, Ra2/Ra1 ≥ 0.87, RSm2/RSm1 ≤ 1.40) to create an ink receiving layer that enhances capillary action and ink absorption. This allows water-based dye ink to achieve both good color development and high optical concentration, resolving the contradiction between ink compatibility and image intensity.

Inventive Principle:
Principle #35Parameter changes

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 controlled surface roughness and coating amount of the recording medium enable the recording of images with high optical concentration and reduced irregularities, maintaining the base material's unevenness and enhancing color development with water-based dye ink.

Implementation Method 1

an ink receiving layer provided on the absorbent substrate and containing an inorganic particle and a binder

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

an ink receiving layer provided on the absorbent substrate and containing an inorganic particle and a binder

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentUS11597227B2Recording medium
Publication Date: 2023.03.07 CANON KK

AI summary

The recording medium includes: an absorbent substrate; and an ink receiving layer provided on the absorbent substrate. The dry coating amount of the ink receiving layer is 6.0 g/m2 or more to 11.0 g/m2 or less, arithmetic average roughness Ra1 (μm) of a surface of the absorbent substrate satisfies a relationship of Expression (1) below, arithmetic average roughness Ra1 and arithmetic average roughness Ra2 (μm) of a surface of the ink receiving layer satisfy a relationship of Expression (2) below, and an average length RSm1 (mm) of a roughness curve element of the surface of the absorbent substrate and an average length RSm2 (mm) of a roughness curve element of the surface of the ink receiving layer satisfy a relationship of Expression (3) below.Ra1≥5.0 μm  (1)Ra2/Ra1≥0.87  (2)RSm2/RSm1≤1.40  (3)