Inkjet Recording Medium Surface Roughness and Reflectance Control
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Solution Overview
Problem
Inkjet recording media fail to produce high-quality images, especially under low exposure conditions such as night views, due to insufficient sharpness, sense of depth, and black depth, despite advancements in surface roughness and ink receiving layer technologies.
Innovation Solution
An inkjet recording medium with a support and ink receiving layer that has specific surface roughness and reflection intensity characteristics, utilizing a combination of water-soluble resins and inorganic particles like silica and alumina to create a porous structure, enhancing ink absorption and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a porous ink receiving layer is used to improve ink absorption and drying speed, then ink receivability and dryability are improved, but image sharpness and black depth remain insufficient
Solution Approach 1:
The patent employs a porous ink receiving layer containing inorganic pigment fine particles (such as silica, alumina, or titanium oxide) with specific surface areas of 50-200 m²/g. The porous structure provides high void ratios (50-80%) that enable rapid ink absorption through capillary action, while the controlled pore size and distribution maintain image sharpness by preventing ink diffusion.
Solution Approach 2:
The patent creates different surface characteristics at different locations within the ink receiving layer. The surface layer has controlled roughness (Ra 0.05-0.5 μm) for sharp image edges, while the underlying porous structure provides rapid absorption. This local differentiation of properties resolves the contradiction between absorption speed and image quality.
2Quantity of substance
If the surface roughness is increased to improve ink absorption, then ink receivability improves, but glossiness and image quality deteriorate
Solution Approach 1:
The patent uses a porous ink receiving layer with high void ratio (50-80%) formed by inorganic pigment fine particles. The porosity provides extensive surface area for ink absorption without requiring increased surface roughness, thus maintaining glossiness. The pore structure enables high ink capacity while preserving surface smoothness for optical quality.
Solution Approach 2:
The patent creates a composite ink receiving layer combining organic binders with inorganic pigment particles (silica, alumina, titanium oxide). This composite structure provides both the porosity needed for ink absorption and the surface smoothness required for glossiness. The inorganic particles form a rigid porous framework while the organic binder maintains surface continuity for light reflection.
3Manufacturing precision
If a semi-glossy surface is used to improve image sharpness and sense of depth, then image quality improves, but black depth and contrast remain insufficient
Solution Approach 1:
The patent employs inorganic pigment fine particles (particularly black pigments like titanium oxide or carbon black) with specific surface areas and refractive indices that enhance light scattering and absorption. These pigments provide deep black tones by maximizing light absorption while the controlled surface roughness maintains sharpness. The pigment properties are optimized to create strong contrast between light and dark areas.
Solution Approach 2:
The patent utilizes spherical or near-spherical inorganic pigment particles that create a specific light scattering pattern. The curved surfaces of these particles enhance light diffusion in a controlled manner, improving black depth through multiple internal reflections while maintaining sharp image edges. The spherical morphology prevents sharp corners that would cause unwanted light leakage.
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 medium achieves superior sharpness, sense of depth, and black depth in images, particularly under low exposure conditions like night views, by controlling the arithmetical mean deviation and peak reflection intensity of the ink receiving layer and support surfaces.
Implementation Method 1
inkjet recording media with ink receiving layers of a porous structure have been developed for practical use. In the inkjet recording media, by using porous structures, high gloss with superior ink receivability (dryability) can be achieved.
Implementation Method 2
inkjet recording media have been proposed that include inorganic pigment fine particles, and water soluble resins, and have high void ratio ink receiving layers provided on a support
Data Source
AI summary
An inkjet recording medium, including a support and an ink receiving layer formed on at least one face of the support, wherein the inkjet recording medium satisfies at least one of the following conditions (i) and (ii): (i) the arithmetical mean deviation of the assessed profile Ra, as specified in JIS-B-0601(2001), of a surface of the ink receiving layer, determined with an evaluation length of 2.5 mm and a cutoff value of 0.8mm, is 0.3 to 1.2 µm, and the peak value (reflectance) of the surface of the ink receiving layer, as determined by a goniophotometer, is in the range of 30 to 80%; and (ii) the arithmetical mean deviation of the assessed profile Ra, as specified in JIS-B0601(2001), of a surface of the support, determined with an evaluation length of 2.5 mm and a cutoff value of 0.8mm, is 0.3 to 1.5 µm, and the peak value (reflectance) of the surface of the support, as determined by a goniophotometer, is in the range of 20 to 80%.