Fuji Photo Film Company, Limited

Youichi Hayata

Michihiro Matsui

Katsumi Ryoke

Masaki Suzuki

Akihiro Hashimoto

Toshihiko Miura

Mikio Ohno

Naoto Murao

Minoru Kanazawa

Nobuyoshi Asada

Koshu Kurokawa

Junji Yazawa

Tatsuya Oguri

Provided is a thin magnetic tape with good tracking and very little output variation in VTRs. The magnetic tape comprises a flexible support, a magnetic layer provided on one side of said flexible support and a backcoat layer provided on the reverse side of said flexible support. The magnetic tape has a stiffness equal to or less than 70 mg&middot;mm in the width direction, an average meandering amount of a tape edge trajectory traced by each of both end in the width direction of said tape observed from the direction perpendicular to said magnetic layer surface is equal to or less than 15 &mgr;m in every end, and an intensity of a meandering component having a cycle of 20 to 200 mm is equal to or less than 30 percent of the intensity of a meandering component having a cycle of 20 to 10,000 mm.

Magnetic tape having specific meandering features

The width measuring apparatus according to this invention includes a light emitting element, a pair of light receiving elements, a measurement support table for fixing them and calculating device, where a pair of partial laser beams of the laser beam from the light emitting element which are not projected over a traveling elongated object to be measured are received by the light receiving elements, and a width of the elongated object calculated from the received light quantities of the pair of partial laser beams. The width measuring apparatus according to this invention further includes a single light emitting element, pairs of light receiving elements, a measurement support table for fixing and calculating devise, where pairs of partial laser beams of the laser beams from the light emitting element which are not projected over traveling elongated objects are received by the light receiving elements, and widths of the elongated objects are calculated from light quantities of the received partial laser beams. Based on the apparatus, it can continuously and optically measure the width of the object in a non-contact fashion with a less amount of measuring error, and measure the widths of the objects at a less expensive cost, securing a working space.

Width measuring apparatus

A method for manufacturing a magnetic recording medium with which a blank web fed from a feeding roller is conveyed by rollers to a cutting blade in the longitudinal direction of the web when magnetic recording mediums are manufactured, the method comprising the steps of primary cutting the blank web in the longitudinal direction into a plurality of sections; and secondary cutting the thus primary cut blank web into plurality of webs each having a given width substantially immediately after the cutting.

Method and apparatus for manufacturing magnetic recording medium

A magnetic recording medium having well-balanced properties with respect to head abrasion characteristics, head cleaning characteristics and drop out characteristics is disclosed, which comprises a non-magnetic support having thereon a magnetic layer containing a ferromagnetic powder and a binder, wherein the magnetic layer has been brought into contact with a carbon steel alloy or super hard alloy made from powders having a Mohs' hardness of at lease 6 and rubbed therewith. A process of producing the magnetic recording medium is also disclosed.

Magnetic recording medium kubbed with a super hard alloy blade

A magnetic recording medium is disclosed, comprising a nonmagnetic support having thereon a magnetic layer on one surface of the nonmagnetic support and a backing layer on the other surface thereof and having a thickness of from 10 to 40 .mu.m, wherein the surface of an edge of the medium which is to be in contact with the inner surface of the flange of a reel of a magnetgic tape cassette, the flange being a base for aligning the edge of the medium when the medium is wound around the reel, is depressed in such a way that the cross sectional area of the depression portion (11) (FIG. 1), as defined by four lines involving an extension line (6) from the surface of the magnetic layer (4) at the edge, an extension line (7) from the surface of the backing layer (5) at the edge, a line (9) which is in tangential contact with the outermost face (8) of the cross section of the edge and which crosses the two extension lines (6) and (7) perpendicularly thereto and a peripheral line (10) of the face of the edge, is from 15 to 60 .mu.m, that the surface roughness (Ra) of the surface of the magnetic layer is 6.5 nm or more (with a cut-off value of 0.25 mm) and that the medium, as a whole, has a Young's modulus (M.sub.0.5) and 550 kg/mm.sup.2 or less. The medium has a high quality and may be wound-up to a tape cassette or the like to have a well aligned form therein in operation for FF(fast forward)/REW(rewind) mode in a VTR.

Magnetic recording medium having a specified edge profile

A magnetic recording medium such as a magnetic recording tape or disk is demagnetized by applying a saturating magnetic field to the magnetic recording medium, then applying an unsaturating magnetic field to the magnetic recording medium in a direction opposite to the direction of the saturating magnetic field, and finally applying an alternating magnetic field to the magnetic recording medium to remove residual magnetism which has been produced on the magnetic recording medium by the unsaturating magnetic field. The saturating, unsaturating, and alternating magnetic fields are generated respectively by a first DC erasing head, a second DC erasing head, and an AC erasing head, which are arranged at spaced intervals in the order named in the direction in which the magnetic recording medium is continuously moved.

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Kanagawa, Japan

Youichi Hayata