Tohoku Ricoh Co., Ltd.

G.r. Advanced Materials Limited

Tohoru Ricoh Co., Ltd.

Keisuke Asada

John Hamilton

Yukako Konno

Yoshihiko Sato

Koji Ono

Yukitaka Watarai

A water-in-oil emulsion ink comprises a water phase and an oil phase, wherein the water phase comprises a pigment, a resin and a water-soluble alcohol or polyol with a boiling point greater than 197&#xb0; C. The ink has improved image recovery properties.

Emulsion ink

A water-in-oil type emulsion ink composed of 10&#x2013;90% by weight of an oil phase and 90&#x2013;10% by weight of an aqueous phase. The oil phase contains an esterified vegetable oil (an esterified vegetable oil obtained by recycling and esterifying edible waste oil such as soybean methyl ester, soybean butyl ester, or tall oil butyl ester).

Water-in-oil type emulson ink for stencil printing

A water-in-oil type emulsion ink for stencil printing, including 10-90% by weight of an oil phase and 90-10% by weight of an aqueous phase, the oil phase containing a mineral oil having a viscosity of at least 8 cSt at 40.degree. C. and such a carbon content distribution that a paraffinic carbon content C.sub.P is at least 55%, a naphthenic carbon content C.sub.N is at least 25% and an aromatic carbon content C.sub.A is not greater than 10%.

Water-in-oil type emulsion ink for stencil printing

A water-in-oil type emulsion ink for stencil printing, including 10-90% by weight of an oil phase and 90-10% by weight of an aqueous phase, the oil phase containing a mineral oil having a viscosity of greater than 10.0 mm.sup.2 /s at 40.degree. C. and such a carbon content distribution that a naphthenic carbon content C.sub.N is at least 34% and an aromatic carbon content C.sub.A is not greater than 20%

A water-in-oil type emulsion ink composed of 10-90% by weight of an oil phase and 90-10% by weight of an aqueous phase. The oil phase contains a petroleum solvent having a kinematic viscosity of greater than 6-10 mm.sup.2 /s at 40.degree. C. and such a carbon content distribution that a naphthenic carbon content C.sub.N is at least 34%, an aromatic carbon content C.sub.A is 2-20% and a paraffinic carbon content CP is less than 55%.

A water-in-oil type emulsion ink for stencil printing, including an oil phase and an aqueous phase. The oil phase contains a pigment and a relatively high molecular weight resin having a weight average molecular weight of between 25,000 and 150,000.

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Miyagi-ken, Japan

Keisuke Asada