Nippon Paper Industries Co., Ltd.

Mizuho Shimoyama

Kenji Hirai

Seiki Yoneshige

Hiroshi Ono

Kaoru Hamada

Hideki Fujiwara

Akihito Ogino

Junpei Natsui

Koichi Yanai

Takashi Date

Fuminari Nonomura

Provision of a thermally sensitive recording medium made up of an undercoating layer containing a pigment and a binder as main components and a thermally sensitive color-developing layer containing a colorless or pale-colored basic leuco dye and a color-developing agent which develops a color by reacting with said basic leuco dye as main components on a substrate, wherein the undercoating layer contains a water-retention agent and a pigment whose oil-absorbing capacity prescribed by JIS K 5105 is from 80 cc/100 g to 120 cc/100 g as a pigment. Further, the solids concentration of a coating for the undercoating layer is from 25% to 45% and the dynamic water-retention capacity, which is Water retention measured with AA-GWR, is 350 g/mor less.

Thermally sensitive recording medium

A thermally sensitive recording medium has at least one layer on a substrate which is a thermally sensitive recording layer that contains a colorless or pale colored electron-donating leuco dye and an electron-accepting color-developing agent. At least one layer on the substrate contains a hydrated silicic acid compound which is treated by wet grinding treatment in a deposition process of the hydrated silicic acid compound. A thermally sensitive recording medium of high brightness, which is superior in color-developing sensitivity and coating layer strength and, further, has excellent head abrasion resistance, less debris adhering and sticking resistance is obtained.

A thermally sensitive recording medium whose luster of printed part is excellent can be provided by a thermally sensitive recording medium of single layer or multi layers having at least a thermally sensitive recording layer that contains a colorless or pale colored electron donating leuco dye and an electron accepting color developing agent on a substrate comprising, containing a pigment whose aspect ratio is 30 or more in at least one layer formed on a substrate.

A surface-treatment agent containing at least one type of processed starch selected from a) to c) as listed below is applied to a base paper of a newspaper so that a product of a B-type viscosity of the surface-treatment agent, measured under conditions of 10% concentration at 50&#xb0; C. (rotor No. 1 at 60 rpm), and an application amount of the surface-treatment agent (both sides) is within a range of 2 to 15 cps&#xb7;g/m;

Growing community of inventors

Tokyo, Japan

Mizuho Shimoyama