Treatment Solution for Ink-Jet Recording Using Basic Amino Acids

The patent changes the chemical composition parameter of the treatment solution by replacing polyallylamine and polyvalent metal ion with basic amino acids (such as lysine, arginine, or histidine) at a concentration of 1% by weight or more. This parameter change resolves the contradiction by achieving improved optical density while maintaining both highlighter-resisting property and storage stability, as basic amino acids provide aggregation capability without the harmful side effects of the conventional additives.

The patent uses basic amino acids which are biodegradable and environmentally friendly alternatives to polyallylamine and polyvalent metal ion. These amino acids achieve the necessary colorant aggregation function temporarily during the recording process, then decompose naturally, avoiding the long-term stability and highlighter-resisting issues caused by persistent conventional additives.

The patent employs basic amino acids as temporary aggregation agents that fulfill their function during the recording process and then decompose. This short-lived action pattern resolves the highlighter-resisting property issue, as the decomposed amino acids do not interfere with highlighter penetration, unlike persistent polyallylamine which continues to prevent highlighter uptake over time.

The patent converts the potential harm of excessive colorant aggregation (which would prevent highlighter penetration) into a benefit by using basic amino acids that provide sufficient aggregation for high optical density but then decompose to allow subsequent highlighter application. This transforms the aggregation function from a permanent barrier into a temporary enhancement.