Core-shell Ink Particles for High-Speed Plain Paper Printing

The patent changes the chemical parameters of the ink by introducing a core-shell structured colorant with specific shell thickness (5-100 nm) and colorant concentration (0.1-50 mass%). This parameter optimization enables the ink to achieve high optical density while maintaining high-speed printing capability on plain paper

The patent uses a composite colorant system consisting of a core part (uncolored component) and a shell part (colored component). This composite structure allows the ink to maintain dispersion stability during high-speed printing while delivering high optical density through the controlled interaction between core and shell components

The patent optimizes the shell thickness parameter to 5-100 nm and colorant concentration to 0.1-50 mass%, which controls the interaction between colorant particles and the recording medium. This parameter control ensures uniform deposition and reaction across solid image areas during high-speed printing

The core-shell structured colorant provides local quality differentiation where the shell part (colored component) interacts with the recording medium to form uniform images, while the core part (uncolored component) maintains dispersion stability. This local functional differentiation achieves both high-speed printing and uniform image quality

The patent introduces a coagulant that changes the physical state of the colorant particles through coagulation. This parameter change reduces particle mobility and prevents feathering and intercolor bleed during high-speed printing while maintaining printing speed

The patent uses a disposable coagulant substance that temporarily alters the colorant particle state during printing and then dissipates. This short-lived action prevents harmful feathering and intercolor bleed during the printing process without affecting subsequent operations