Inkjet Coating Composition Using Modified Calcium Carbonate
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Solution Overview
Problem
Traditional coated papers for inkjet printing suffer from high costs due to the use of expensive pigments like silica and alumina, leading to slow absorption rates and poor print quality, while low-cost alternatives result in dense coating structures that are not suitable for inkjet printing, causing issues like slow drying, graininess, and poor water resistance.
Innovation Solution
A novel pigmented coating composition for inkjet media using a combination of modified calcium carbonate (MCC) and precipitated calcium carbonate (PCC) or clay, along with a hydrophilic binder, which provides a high absorption rate and improved print quality without relying on high-cost pigments, and optional polymeric co-pigments and additives for enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If expensive pigments like silica and alumina are used in coated paper, then absorption rate and print quality are improved, but manufacturing cost increases
Solution Approach 1:
The patent uses a composite coating formulation combining calcium carbonate (as the primary pigment) with specific binders (polyvinyl alcohol, polyacrylic acid) and additives (silica fume, alumina in controlled amounts). This composite approach allows achieving good print quality through the synergistic effect of inexpensive calcium carbonate combined with functional binders and minor expensive additives, rather than relying solely on expensive pigments like silica or alumina.
Solution Approach 2:
The patent optimizes the particle size distribution of calcium carbonate (combining fine particles <10 µm with medium particles 10-30 µm) and controls the ratios of coating components to achieve optimal absorption characteristics. By changing the physical parameters of the coating formulation, the patent achieves high-quality prints using inexpensive calcium carbonate instead of expensive pigments.
2Ease of manufacture
If low-cost pigments like calcium carbonate are used in coated paper, then manufacturing cost is reduced, but absorption rate and print quality deteriorate
Solution Approach 1:
The patent creates a composite coating system where calcium carbonate is combined with specific binders (polyvinyl alcohol, polyacrylic acid) and functional additives. This composite formulation enhances the inherent limitations of inexpensive calcium carbonate by providing binding strength and controlled absorption characteristics through the binder-additive matrix, thereby achieving acceptable to good print quality at low cost.
Solution Approach 2:
The patent utilizes the porous structure of calcium carbonate particles and controls the porosity of the coating layer through formulation optimization. The porous nature of calcium carbonate provides adequate absorption capacity for inkjet printing, and the coating formulation maintains controlled porosity to prevent excessive absorption while ensuring adequate ink uptake for quality printing.
3Quantity of substance
If high surface area pigments are used in coating, then absorption capacity is improved, but total solid content decreases and manufacturing cost increases
Solution Approach 1:
The patent changes the particle size parameters of the pigment, using a bimodal distribution with fine particles (<10 µm) and medium particles (10-30 µm). This parameter change optimizes the balance between absorption capacity and solid content, as the medium particles provide bulk and maintain solid content while the fine particles contribute to absorption capacity through their high surface area to volume ratio.
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 novel coating composition enhances ink absorption and print quality, reducing graininess and improving image gloss, while maintaining low manufacturing costs and energy efficiency, thus addressing the limitations of both high-cost and low-cost pigment-based coatings.
Implementation Method 1
The inks used in inkjet printers are typically aqueous inks, which contain a minor amount of dye or pigment colorants and a large amount of water and co-solvents as the ink vehicle. Thus, the absorption property of the papers greatly affects the print quality.
Implementation Method 2
As a consequent, during the manufacturing of the coated media, a lot of energy is required to remove the water or solvent from the coating layer, thus, the coating speed is limited by the drying capability.
Data Source
AI summary
A coated medium for inkjet printing, which includes a supporting substrate and a coating layer formed on at least one side thereof. The coating layer includes at least one binder and at least two different inorganic pigments: modified calcium carbonate (MCC) and either precipitated calcium carbonate (PCC) or clay.