Matsushita Electric Industrial Co., Ltd.

Kiyoshi Kobata

Kazunori Kubota

Kazunori Sakamoto

Hideki Okumura

Masaru Watanabe

Yukihiro Shimasaki

Tsumoru Ohata

Fumio Echigo

Tousaku Nishiyama

Hideo Hatanaka

Yasuhiro Ueyama

Kiyokazu Imanishi

Wataru Watanabe

Tetuo Fuchi

Takumi Haneda

Hirofumi Ito

The present invention provides a thin multilayer magnetic recording medium having improved electromagnetic conversion property and durability, comprising coating layers of a lower non-magnetic layer and an upper magnetic layer. The non-magnetic layer of this magnetic recording medium comprises a non-magnetic needle body having an average major axis length of 0.25 to 1.0 .mu.m and an average minor axis length of 0.005 to 0.0151 .mu.m, a first binding resin having a glass transition temperature (Tg.sub.1) of 30 to 50.degree. C., and fatty acid ester. The content of the first binding resin is 15 to 30 wt % with respect to the non-magnetic needle body. The content of the fatty acid ester is 2 to 15 wt % with respect to the first binding resin. The magnetic layer having a dry thickness of 0.5 .mu.m or less comprises ferromagnetic powder and a second binding resin having a glass transition temperature (Tg.sub.2) of 40 to 70.degree. C. Tg.sub.1 is at least 5.degree. C. lower than Tg.sub.2, and the entire thickness comprising the layers and the film is 12 .mu.m or less.

Magnetic recording medium

A magnetic recording medium including a non-magnetic polymeric support and a magnetic layer on the non-magnetic polymeric support. The magnetic layer is positioned to be in contact with a record/playback head and includes ferromagnetic powder, abrasive material and binder resin, with at least 40 parts by weight of the abrasive material per 100 parts by weight of the ferromagnetic powder. The ferromagnetic powder has a saturation magnetization .sigma.s of 80 emu/g or more and long axis length of 0.25 .mu.m or less.

A tape cassette has a pair of reels each including a reel hub, with each hub having an anchor groove defined in an outer peripheral surface thereof so as to extend in a lengthwise direction thereof. A generally elongated clamping piece is received within the anchor groove and has a predetermined width as measured circumferentially of the reel hub. A tape medium includes a length of magnetic recording tape having opposite ends, and a leader tape connected with each of the opposite ends of the length of magnetic recording tape by of a splicing tape of a predetermined length. One end of the leader tape remote from the length of magnetic recording tape is received within the reel hub and anchored to the reel hub with the clamping piece snapped into the anchor groove. The splicing tape is, when the tape medium is wound around the reel hub, positioned immediately radially outwardly of and encompassing the predetermined width of the clamping piece.

Tape cassette having a minimized clamp set

A sheet-shaped cleaner including a resilient film and nonwoven cloth consisting of synthetic fibers formed on one side of the film is disposed in opposition to a guide roller. A magnetic tape is sandwiched between the guide roller and the cleaner and with the magnetic surface of the magnetic tape being contacted by the nonwoven cloth of the cleaner. The film of the cleaner is wedged between locking portions of the cassette in order to cause the cleaner to bow in a direction away from the guide roller such that the nonwoven cloth of the cleaner is biased under a low force against the magnetic surface of the tape. Accordingly, foreign matter on the surface of the magnetic tape is removed.

Tape cassette with resiliently mounted tape cleaner

A magnetic recording and/or reproducing device for recording information on a disc-like magnetic recording medium and/or reproducing the information from it, said magnetic recording and/or reproducing device having a pair of magnetic head members each composed of a magnetic head chip and a slide pad for slidably holding the disc-like magnetic recording medium at its both surfaces between the pair of magnetic head members under a predetermined contact pressure, wherein the slide pad is so disposed as to surround the magnetic head chip and the top portion of the magnetic head chip is so disposed as to protrude by a predetermined amount from a sliding contact surface between the slide pad and the disc-like magnetic recording medium. It makes possible by the magnetic recording and/or reproducing device of the above described type to obtain such a desirable state in which the disc-like magnetic recording medium can be steadily held in contact with the magnetic head chips, since the slide pads act primarily to minimize the warp of the disc-like magnetic recording medium and also the deformation of the disc-like magnetic recording medium which would result from a deviation in position of one or both of the magnetic head members relative to the disc-like magnetic recording medium.

Flexible recording medium tensioning magnetic recording head

Growing community of inventors

Takatsuki, Japan

Kiyoshi Kobata