Tdk Corporation

Konica Corporation

Yoshihisa Osawa

Ryuji Hosogaya

Hideki Tanaka

Seiichi Tobisawa

Eizo Tsunoda

Akira Hatakeyama

Fuminori Tokuda

Masatoshi Uchida

The center line average roughness (Ra) of the slit inner surfaces is made in a predetermined range of 5.0 .mu.m according to the present invention, and the straightness (W1) in the delivery direction of the coating solution thereof and the straightness (W2) in the perpendicular direction to the delivery direction thereof are made in predetermined ranges respectively in preferred embodiments. Thereby, development of wrinkles and inclined elongation in the tape itself are prevented when wound on a roll, the productivity is increased, and the product quality is improved.

Extrusion type coating head

A coating apparatus having an extrusion type coating head to form a coating on the surface of a support by extruding a coating liquid continuously or successively from a slit, wherein the slit is tapered so as to expand or become wider gradually from its inlet end so as to allow the coating liquid to be extruded toward its outlet end and apply the coating liquid onto the surface of the support and wherein an opening slit width (d1) at the inlet end of the slit and an opening slit width (d2) at the outlet end thereof satisfies the following relations:

Coating apparatus

In a coating apparatus having an extrusion coating head, the working value H of a back end edge which corresponds to an end portion at the downstream side of a support feeding direction of a back edge of the extrusion coating head is set to 25 .mu.m or less, and the straightness of said back end edge with respect to the coating width is set to 5 .mu.m or less. Accordingly, a coating operation to form coated films at a stable thickness can be stably performed without occurrence of streaks and coating unevenness on the films, and a judgment on coating surface characteristics can be readily performed without actually carrying the coating operation.

In an extrusion type coating head according to the present invention, a center line average roughness (Ra) of an inner wall surface of a pocket is made in a predetermined range of 3.5 .mu.m or less and preferably a curvature part is provided, in the part where a surface of a slit joins to a surface of the pocket, which has the radius of curvature R of within a predetermined range. By these configurations, an easiness of cleaning in the pocket of the extrusion type coating head which is difficult to be cleaned is remarkably improved in particular, the rate of operation is improved, labor is saved, and adverse effects are prevented that might be brought by insufficient cleaning on the product coating such as streak generated on the coating surface and thickness fluctuation in the coating.

To manufacture a magnetic recording medium with reduced coating defects by effectively and reliably removing foreign matter that causes coating striations. In a manufacturing method for a magnetic recording medium that includes a process in which a magnetic layer is formed on a flexible support, the aforementioned magnetic layer is formed after cleaning the aforementioned flexible support by bringing it into contact with a rotating cleaning roll, the contact surface of which consists of at least an adhesive substance or with a cleaning member, the contact surface of which consists of at least a porous polymer and so providing a manufacturing method for a magnetic recording medium in which foreign matter, which causes coating striations, can be efficiently and reliably removed and in which it is possible to manufacture a magnetic recording medium with reduced coating defects.

Growing community of inventors

Miyota-machi, Japan

Yoshihisa Osawa