Fitch, Even, Tabin & Flannery
Emulsion ink for stencil printing
A water-in-oil (W/O) emulsion ink for stencil printing is provided which is prevented from pigment aggregation and thus excellent in ink fixability, high in printing density and less declining in printing density even after printing many sheets. The emulsion ink has a ratio by volume of the water phase to liquid components of the oil phase (i.e., volume of water phase/volume of the liquid components of oil phase) in a range of 1.0 to 3.5, preferably 1.0 to 3.0 at 23&deg; C. The liquid components of the oil phase may be composed of a resin, a solvent and a surfactant. The oil phase can contain a pigment at a ratio by volume of 0.19 or less to the total volume of the oil phase. The pigment preferably has an average particle size of 0.02 to 1.5 (&mgr;m). The water phase preferably has an average particle size of 0.1 to 1.0 (&mgr;m). The ink is suitable for containing particles of organic pigments with non-uniform shapes and a large average particle size like copper phthalocyanine blue and diaxazine violet.
Riso Kagaku Corporation
C
C09D
inventional
Hiromichi Sadanao Hiroyuki
Yamada Okuda Ogawa