Fuji Photo Film Company, Limited

Fujifilm Corporation

Tadashi Ishiguro

Masaaki Fujiyama

Katsumi Ryoke

Satoru Hayakawa

Takeshi Kakuta

Kazuo Kato

Akihiro Matsufuji

Nobuo Tsuji

Katsumi Araki

Noburo Hibino

Masami Sato

Hiroaki Doushita

Yasutoshi Okuzawa

Yutaka Kakuishi

Minoru Sueki

Kenichi Nakamura

Kunihiko Honda

An aspect of the present invention relates to a magnetic recording medium comprising on one surface of a nonmagnetic support a nonmagnetic layer containing a nonmagnetic powder and a binder and a magnetic layer containing a ferromagnetic powder and a binder in this order, as well as comprising a backcoat layer on the other surface of the nonmagnetic support. The nonmagnetic layer is a radiation-cured layer formed by curing with radiation a given radiation-curable composition, and the backcoat layer comprises filler particles with an average primary particle diameter, D50, ranging from 0.05 to 1.0 &#x3bc;m, the filler particles being selected from the group consisting of organic polymer particles and inorganic colloidal particles.

Magnetic recording medium

A cleaning medium comprising: a backcoat layer; a nonmagnetic support; and a cleaning layer containing ferromagnetic powder and a binder, in this order, wherein the cleaning layer has projections having a height of 10 nm or higher on a surface of the cleaning layer at a density of from 0.10 to 5.0/&#x3bc;mand a surface microhardness of from 294 to 784 MPa.

Cleaning medium

A leader tape having: a support; an upper layer containing a powder, a binder, and a lubricant; and a lower layer containing a powder, a binder, and a lubricant which is at least 1.12 times as much as the lubricant of the upper layer; wherein the support, the lower layer, and the upper layer is in this order.

Leader tape and magnetic tape cartridge

A cleaning medium for a magnetic recording apparatus is disclosed, comprising a nonmagnetic support having provided thereon a lower coating layer mainly containing a nonmagnetic inorganic powder and a binder, and a cleaning layer containing at least a ferromagnetic inorganic powder and a binder provided on the lower coating layer, wherein the thickness of the cleaning layer is from 0.05 to 1.0 &#x3bc;m, the thickness of the lower coating layer is from 0.2 to 5.0 &#x3bc;m, the thickness of the support is from 2.0 to 10 &#x3bc;m, and the thickness in total of the cleaning medium (cleaning tape) is from 4.0 to 15 &#x3bc;m.

Cleaning medium for magnetic recording apparatus

A polishing member for use in polishing of an end face of an optical fiber connector ferrule comprises a substrate and a polishing layer, which is overlaid on the substrate and which comprises a binder and fine polishing particles dispersed in the binder. Agglomerated fine silica particles having a mean particle size falling within the range of 0.1 &mgr;m to 4 &mgr;m are utilized as the fine polishing particles contained in the polishing layer, and a thickness of the substrate falls within the range of 25 &mgr;m to 150 &mgr;m. The polishing with the polishing member is performed while a polishing liquid, which is constituted of water or a silica slurry, is being supplied onto a surface of the polishing layer. The polishing liquid is free from a base or an acid. The polishing layer has a dry thickness falling within the range of 5 &mgr;m to 15 &mgr;m.

Polishing member and process for producing the same

An abrasive member for a very high return loss optical connector ferrule is used in abrading an end of an optical connector ferrule having a ferrule hole, in which an optical fiber has been inserted and secured, into a convex spherical surface. The abrasive member comprises a flexible substrate and an abrasive layer, which is formed on the surface of the flexible substrate and comprises a binder and abrasive grains. The surface roughness Ra, expressed in terms of arithmetic mean deviation, of the abrasive layer falls within the range of 0.01 .mu.m to 0.05 .mu.m. The abrasive member carries out polishing such that the surface smoothness of the ferrule surface and the optical fiber surface may be kept high, such that a difference in level between the ferrule surface and the optical fiber surface may not occur, and such that the very high return loss characteristics may thereby be obtained.

Abrasive member for very high return loss optical connector ferrules

An abrasive member comprises a non-magnetic substrate and a plurality of abrasive layers, which are overlaid upon the non-magnetic substrate, each of the abrasive layers mainly containing a binder and hard abrasive grains, which have a Mohs hardness of at least 6 and are dispersed in the binder. The plurality of the abrasive layers include a top abrasive layer and a lower abrasive layer, which is formed between the non-magnetic substrate and the top abrasive layer. The thickness of the top abrasive layer is at most A/2, where A represents the thickness of the lower abrasive layer. The mean grain diameter of the abrasive grains contained in the top abrasive layer is at most B/2, where B represents the mean grain diameter of the abrasive grains contained in the lower abrasive layer.

Abrasive member

A magnetic tape cassette whose reliability is considerably improved by preventing triboelectrification by tape-and-guide friction. A metal tape guide for guiding the magnetic tape while in contact with the back surface of the tape. The substrate of the magnetic tape is made of polyethylene terephthalate or polyethylene naphthalate, and has a surface specific resistance R.sub.s of 10.sub.8 .OMEGA./cm.sup.2 or more. The tape guide is made of stainless steel or aluminum, and the surface roughness of the tape guide is such that the root mean square roughness value R.sub.rms, as determined by height from a reference surface, is 60 nm or lower. Also, the back surface of the tape may be provided with 30 to 400 protrusions of a height of 300 nm per 0.1 mm.sup.2.

Magnetic tape cassette having improved magnetic tape substrate and tape

A magnetic recording medium is disclosed, which is formed by providing on a non-magnetic support, a lower layer comprising at least one of a ferromagnetic powder and a non-magnetic powder dispersed in a binder, and providing on the lower layer while the lower layer is in a wet condition, an upper magnetic layer comprising a ferromagnetic powder dispersed in a binder, wherein the upper magnetic layer has a dry thickness of 1.0 .mu.m or less, and the non-magnetic support is a multi-layer structural support comprising at least an uppermost support layer and a lowermost support layer, wherein the uppermost support layer is coated with the lower non-magnetic or magnetic layer, each of the uppermost layer and the lowermost layer comprises a biaxially oriented film comprising a thermoplastic resin containing filler particles, and the uppermost support layer has a center line average surface roughness Ra in the range defined by the following formula:

Magnetic recording medium containing a biaxially oriented multilayer

A process for the preparation of a magnetic recording disk comprises the steps of providing a magnetic recording layer on a surface of a nonmagnetic support, punching the nonmagnetic support together with the magnetic recording layer into a disk having a circular hole in its central portion, and fitting mechanical members including a center core made of a synthetic resin into the hole of the support. The nonmagnetic support having the magnetic recording layer and at least the center core of the mechanical members are subjected to heat treatment independently prior to fitting the mechanical members including the center core into the hole of the support.

Process for the preparation of magnetic recording disk

A magnetic recording medium which comprises a non-magnetic support having thereon a magnetic recording layer comprising ferromagnetic particles dispersed in a binder, with the magnetic layer further containing an organoaluminum compound or with the surface of the ferromagnetic particles being treated with an organoaluminum compound.

Growing community of inventors

Kanagawa, Japan

Tadashi Ishiguro