Nippon Paper Industries Co., Ltd.

Akinobu Chatani

Takashi Ueno

Yoshihiro Kuroyama

Noboru Kondo

Makoto Hasegawa

Hiroki Yamamoto

Tadashi Yoshida

Atsushi Ono

Takashi Ochi

Yasuo Yamamoto

Hirokazu Morii

Koji Kutsuwa

Koichi Yanai

Teiichi Otani

Takanori Otsuhata

Koji Okomori

Hiroshi Koyamoto

Yoshifumi Iimori

Satoshi Tsuda

Yuji Ozawa

Dai Nagahara

Noriko Kumazawa

Kunio Takebayashi

Hitoshi Nagao

Misaki Watanabe

Nobuo Nakanishi

Ryuta Ono

Teruaki Ookawa

An inkjet recording medium, comprising an ink-receiving layer containing a pigment, a binder and an inkjet ink-fixing agent comprising a cationic compound disposed on at least one surface of a base paper, wherein 50% or more by weight of calcium carbonate is contained in terms of a solid content based on a total amount of the pigment contained in the ink-receiving layer; 75 to 90 parts by weight of the pigment, 1 to 10 parts by weight of the binder and 5 to 20 parts by weight of the inkjet ink-fixing agent are contained based on 100 parts by weight of the ink-receiving layer; the drop water absorbency of the ink-receiving layer (according to the drop water absorbency defined in Japan Technical Association of the Pulp and Paper Industry, J. TAPPI, No. 32-2:2000 except that a drop water amount is 0.001 ml) is 200 seconds or less; and a Stockigt sizing degree according to JIS-P-8122 for the inkjet recording medium is 5 seconds or less.

Inkjet recording medium

A method for manufacturing an inkjet recording medium comprising the steps of: applying a coating color containing a pigment and a binder as major components to at least one side of a base material using a transfer roll coater, subsequently drying coating layer to form an ink absorbing layer, wherein Hercules viscosity of coating color is 5 m Pa&#xb7;s to 30 m Pa&#xb7;s and pigment contains a synthetic silica having an oil absorption of 90 ml/10 g to 200 ml/100 g, a BET specific surface area of 45 m/g to 200 m/g and an average particle diameter of 1.0 &#x3bc;m to 3.0 &#x3bc;m and/or a precipitated calcium carbonate-silica composite having an oil absorption of 100 ml/10 g to 250 ml/100 g, a BET specific surface area of 5 m/g to 150 m/g and an average particle diameter of 1.0 &#x3bc;m to 10 &#x3bc;m.

Process for producing inkjet recording medium

The present invention aims to provide coated printing papers having fast ink drying properties comparable to those of conventional newsprint, without stickiness, having good printability such as sharpness of printed images comparable to those of coated papers, as well as having the effect of decomposing harmful substances by exposure to light, especially when using penetration drying type news inks. A coated printing paper is provided, comprising a coating layer containing a pigment and an adhesive on a base paper, characterized in that a fine titanium oxide powder having a photocatalytic effect is contained in the coating layer and that the coated paper has an oil absorbency of 20 g/mor more under pressure and a Bekk smoothness of 75 seconds or less.

Coated printing papers

A printing sheet which prevents setoff while transferring a sufficient quantity of ink and maintains necessary dot uniformity can be obtained by ensuring characteristics that the centerline average roughness showing the larger value is 1.0-3.5 &mgr;m and the ratio of centerline average obtained by dividing the larger value by the smaller value is less than 1.15 where said values are chosen at the point where the difference between the centerline average roughness in a certain direction and the centerline average roughness at right angles to said direction is maximal. Further, the abovementioned quality is further improved by appropriately ensuring that the oil absorbability is more than 4 mg/cm and less than 7 mg/cm when the contact time between the oil component having a surface tension of 27-30 mN/m at 20&deg; C. and the printing sheet is 5 seconds and/or that the median pore diameter is 1.7-3.5 &mgr;m, in addition to the abovementioned characteristics.

Printing sheet

An ink jet recording paper, which is excellent in ink absorbency and color-developing properties and has dull-tone glossiness, comprising an ink-receiving layer and at least two colloidal silica layers applied successively onto a support, each of said colloidal silica layers comprising chain colloidal silica as a main ingredient, wherein at least the colloidal silica layer contacting the ink-receiving layer contains no binder and has a coverage of about 1 to 3 g/m , and the coverage of other colloidal silica layer is about 1 to 6 g/m .

Ink jet recording paper and the production thereof

Ink jet recording sheet

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Tokyo, Japan

Akinobu Chatani