Recording Medium Surface Roughness Control for Undertrapping and Scratch Visibility
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Solution Overview
Problem
Recording media experience issues with undertrapping, visibility of scratches, and mottled patterns due to surface roughness and solvent transfer, which existing methods struggle to adequately address.
Innovation Solution
A recording medium with an arithmetic average roughness of 1.1 to 2.5 µm and controlled skewness and average length of roughness curve elements, achieved through methods such as adding particles or embossing substrates, to inhibit undertrapping and reduce scratch visibility while preventing mottled patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the surface roughness of the recording medium is increased to inhibit undertrapping and reduce scratch visibility, then undertrapping and scratch visibility are improved, but ink may collect in dented portions causing mottled patterns
Solution Approach 1:
The patent applies parameter changes by precisely controlling multiple surface roughness parameters (Ra, Rsk, RSm) within specific ranges. By adjusting Ra to 1.0-3.0 μm, Rsk to -0.5 to 0.5, and RSm to 0.05-0.5 mm, the invention optimizes the balance between reducing undertrapping/scratch visibility and preventing ink collection in dented portions, thereby resolving the contradiction between improving harmful factors and maintaining manufacturing precision
Solution Approach 2:
The patent applies local quality by controlling the distribution and characteristics of surface irregularities through specific roughness parameters. The controlled skewness (Rsk) and average length of roughness curve elements (RSm) create a specific local surface structure that prevents ink from collecting in excessive dented portions while maintaining sufficient roughness to reduce undertrapping and scratch visibility
2Manufacturing precision
If the surface roughness is decreased to improve manufacturing precision and ink uniformity, then mottled patterns are reduced, but adhesion between recording media increases causing undertrapping
Solution Approach 1:
The patent resolves this contradiction by changing the parameters of surface roughness to a specific range (Ra: 1.0-3.0 μm, Rsk: -0.5 to 0.5, RSm: 0.05-0.5 mm). This parameter optimization ensures sufficient surface roughness to reduce adhesion and undertrapping while maintaining ink uniformity and preventing mottled patterns
3Object-affected harmful factors
If the surface roughness is increased to reduce scratch visibility, then scratch visibility is improved, but the glossiness of the outermost surface decreases
Solution Approach 1:
The patent applies parameter changes by controlling the surface roughness parameters within specific ranges. The controlled Ra (1.0-3.0 μm) and RSm (0.05-0.5 mm) values provide sufficient surface irregularity to reduce scratch visibility while the controlled Rsk (-0.5 to 0.5) maintains a balance that preserves appropriate surface glossiness
Data Source
AI summary
The invention provides a recording medium capable of inhibiting occurrence of undertrapping, lowering the visibility of scratches on the outermost surface of the recording medium and inhibiting occurrence of a mottled pattern when recording is conducted. The recording medium has a substrate and an ink receiving layer provided on the substrate, wherein the arithmetic average roughness Ra of the outermost surface of the recording medium as prescribed by JIS B 0601:2001 is 1.1 µm or more and 2.5 µm or less, and the skewness Rsk of a roughness curve of the outermost surface of the recording medium as prescribed by JIS B 0601:2001 is 0.1 or less.