Riso Kagaku Corporation

Hajime Tsunoda

Hiroyuki Ogawa

Toshihiro Endo

Osamu Matsumoto

Teruaki Ohkawa

Kazuhiro Higashi

An ink for inkjet printing including a pigment, a water-dispersible resin, water, and a water-soluble organic solvent, wherein the water-dispersible resin is an anionic resin having a film elongation of 400-1,000%, a tensile strength of 20 to 50 N/mmand an absolute value for the zeta potential (mV) of 40 or greater, the amount of the anionic resin, reported as a weight ratio relative to the pigment, is within a range from (0.5 to 2.5)/1, and the surface tension of the ink is within a range from 30 to 50 mN/m.

Ink for inkjet printing

An ink for inkjet recording containing a vehicle, coloring agents dispersed therein, and a dispersing agent for the coloring agents as required, is provided. The vehicle contains at least a first solvent component and a second solvent component. The first solvent component has the lowest boiling point among the components in the ink, and has a higher viscosity than the ink. The second solvent component has a higher boiling point than the first one. The boiling point of the first solvent component is preferably 280 degree C. or below, and the content thereof is preferably 10 to 80% by weight based on the total weight of the ink. Even when the ink is printed on non-coated papers, the vehicle penetrates little in the thickness direction and bleeds little in the horizontal direction. Clogging in the nozzles can be prevented effectively using the ink even when it has been left in an open atmosphere for a long time.

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Ibaraki-ken, Japan

Hajime Tsunoda