Oji Paper Co., Ltd.

Makiko Tokita

Kenji Yasuda

Akira Kobayashi

Masahiro Nakagawa

Hisao Maruyama

Masahiko Kitajima

Masao Maekawa

An ink-jet recording sheet that contains as main ingredients 69-95% wood pulp and 4-30 wt % precipitated calcium carbonate and which has a Stockigt sizing degree of 2-25 seconds as measured for a basis weight of 64 g/m.sup.2, or a Stockigt sizing degree ranging from 5.times.(basis weight/64).sup.2 to 25.times.(basis weight/64).sup.2 at a water extracting pH of 4.5-7.5. This sheet allows a clear color to develop and provides an image having circular dots and sharply defined edges. This sheet may also incorporate a cationic synthetic polymer and an alkylketene dimer.

Ink-jet recording sheet

An ink jet recording sheet having an enhanced ink-absorbing property and bright color image-forming property and an excellent surface hardness has a specific coating layer formed on a surface of a substrate sheet, which comprises a pigment and a resinous binder composed of a cationic copolymer prepared by copolymerizing (a) 99.95 molar % or less of a principal copolymerization component comprising at least one fatty acid vinyl ester comonomer with (b) 0.05 to 0.4 molar % of a cationic copolymerization component comprising at least one cationic comonomer having an ethylenically unsaturated hydrocarbon radical and a cationic radical selected from tertiary amino radicals and quaternary ammonium radicals and, optionally, a member selected from (c) an additional copolymerization component comprising at least one polymerizable non-ionic comonomer different from the fatty acid vinyl ester and (d) a graft copolymerization component comprising polyvinyl alcohol.

Ink jet recording sheet and process for producing same

An ink jet recording sheet includes a sheet-like substrate composed mainly of 70 to 100 wt % of wood pulp and 0 to 30 wt % of precipitated calcium carbonate and having a Stockigt sizing degree of not less than 2 seconds and not more than 25 seconds when formed into a sheet having a basis weight of 64 g/m.sup.2, and a coating layer composed mainly of white pigment, with the coating layer being formed on at least one side of the substrate at a weight of 1 to 10 g/m.sup.2. This sheet has a high ink absorption rate and is able to develop bright colors and sharp images.

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Chiba, Japan

Makiko Tokita