Novel techniques for examining fixation processes of a dye ink dot on paper and three-dimensional geometry of the fixed ink dot were developed and applied.Most magenta and black dye inks for ink-jet contain fluorescence agents or use fluorescence dyes specific of the color. Fluorescence emitted from those of the ink-jet inks provides a three dimensional ink distribution by the optical slicing function of a confocal laser scanning microscope. In applications, several facts were revealed. Ink dot shape was like a coin with a constant thickness on photo quality paper. Ink spreads over crack surfaces on high gloss type paper a few times deeper than the normal penetration.Microscopic high-speed video capture system was established to visualize ink drop spread on and penetration into paper. Changes in ink dot area and dot roughness with time were evaluated from microscopic video images. Ink drop behavior on trial coated paper from commercially available calcium carbonate pigment and from its ball-milled pigment was recorded. Small particle size by ball milling reduced the dot area, but dot area continued to change for a longer time than that for the untreated sample, as is explained in terms of small pore size according to Lucas-Washburn's equation.