Fuji Photo Film Company, Limited

Hiromi Nakahara

Hiroshi Ogawa

Yasuo Tamai

Masaaki Fujiyama

Tsutomu Okita

Nobuo Tsuji

Tadashi Yasunaga

Masashi Aonuma

Eiichi Tadokoro

Keiji Tanaka

Masahiko Furukawa

Isao Yamamoto

Masaaki Igarashi

Kouichi Mochizuki

A method is described for producing a metal thin film type magnetic recording medium having a ferromagnetic metal or alloy thin film provided on a non-magnetic support, comprising the steps of forming said ferromagnetic metal or alloy thin film on said non-magnetic support, and then buffing the surface of said ferromagnetic metal or alloy thin film with nonwoven fabric.

Method for producing magnetic recording media

A method for preparing a magnetic recording medium comprising the steps of: dispersing ferromagnetic particles in a binder solution; coating the resulting magnetic coating composition on a nonmagnetic support to provide a magnetic layer; drying the magnetic layer; and providing a calendering treatment with the magnetic layer, wherein the binder solution comprises at least one compound selected from the group consisting of a polyurethane resin having a tan .delta. peak temperature of 30.degree. C. or higher as a result of measuring dynamic viscoelasticity, a cellulose acetate butyrate, a cellulose acetate propionate, and a butyral resin; and when the magnetic layer is dried until the solvent content of the magnetic layer is in the range of from 0.1 to 3 wt %, the calendering treatment is provided with the magnetic layer.

Method for preparing magnetic recording medium

In a supercalender consisting of a metal roll and an elastic roll and smoothing a web by nipping the web between the metal roll and the elastic roll, the elastic roll satisfies the condition of:

Calender roll for supercalender

The present invention relates to a magnetic recording medium having on a non-magnetic support a magnetic layer comprising a ferromagnetic fine powder in a binder, in which a colloidal silica having a diameter of 7 to 50 m.mu. and methyl groups on the surface thereof is added in a proportion of 2 to 20 parts by weight to 100 parts by weight of the ferromagnetic fine powder during dispersion of the coating composition of the ferromagnetic fine powder.

Magnetic recording medium

This invention relates to a magnetic recording substance comprising a support and a magnetic layer containing a ferromagnetic metal powder of liquid phase reduction type in a binder, the ferromagnetic metal powder being obtained by mixing an aqueous slurry containing the ferromagnetic metal powder with an organic solvent capable of forming a minimum boiling azeotropic mixture with water and subjecting the mixture to distillation to remove the water.

Magnetic recording substance

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Kanagawa, Japan

Hiromi Nakahara