Ink jet recording sheet
AssigneeOji Paper Co., Ltd.
InventorsMakiko Tokita, Masahiro Nakagawa, Akira Kobayashi, Kenji Yasuda
Life of this patent
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Abstract
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.
Claims11
An ink jet recording sheet comprising a substrate in the form of a sheet composed mainly of 70 to 100 wt% wood pulp and 10 to 25 wt% precipitated calcium carbonate selected from the group consisting of (1) a calcite having a particle size distribution such that not less than 80% of the particles as measured by the natural precipitation method range from 0.5 to 1.5 .mu.m in size, a specific surface area ranging between 10 to 30 m.sup.2 /g and an oil absorption ranging between 30 and 80 ml/100 g;
- and (2) a calcite having a mean particle size ranging between 1 and 5 .mu.m, a specific surface area ranging between 1 and 10 m.sup.2 /g and an oil absorption ranging between 30 and 50 ml/100 g, and having a Stockigt sizing degree of not less than 5 seconds and not more that 15 seconds when formed as a sheet having a basis weight of 64 g/m.sup.2, and a coating layer composed mainly of white pigment, said coating layer being formed on al least one side of said substrate at a weight of 1 to 10 g/m.sup.2.
Dependencies are inferred from the claim text.