Fuji Photo Film Company, Limited

Takuzi Yamada

Takahito Miyoshi

Yasutoshi Okuzawa

Tsutomu Sugisaki

Minoru Kanazawa

Seizi Tsuyuki

A magnetic tape reel in which transformation of the tape winding surface owing to the heat shrinkage after molding is suppressed, and also transformation of the hub hole owing to the winding tension of the magnetic tape is suppressed. At least a tape winding drum portion is provided with concentric cylindrical portions including an inner cylindrical portion having a hub hole to be engaged with a rotary driving shaft, an intermediate cylindrical portion provided concentrically with and outside the inner cylindrical portion, and an outer cylindrical portion provided concentrically with and further outside the intermediate cylindrical portion so as to form a tape winding surface. The intermediate cylindrical portion and the outer cylindrical portion are connected to each other through a plurality of reinforcing ribs which extend in the radial directions of the reel but which are not present between the inner cylindrical portion and the intermediate cylindrical portion.

Reel for magnetic tape

A magnetic tape cassette having a guide pole which is in sliding contact with the magnetic surface of the tape produced in such a manner as to improve the running characteristics of the tape while being capable of being manufactured at a low cost. A cylindrical stainless steel base member is subjected to a barreling treatment so as to secure fine particles of an inorganic material having a Moh's hardness of greater than 9 to the slide surface of the guide post. Moreover, the surface of the guide pole can be finished by a surface rolling to reduce the number of scratch-like grooves in the slide surface having a depth of more than 0.2 .mu.m and a width of less than 40 .mu.m to less than 11 per millimeter in the sliding direction of the tape.

Magnetic tape cassette having improved guide pole structure

A tape reel for a magnetic tape cassette having an improved circularity of the tape winding cylinder wall and which is more durable than conventional reels. The reel includes an inner cylinder having pawls which engage with a rotating shaft, an outer cylinder provided outside the inner cylinder and coaxial therewith to provide a tape winding cylinder, a plurality of reinforcing ribs extending between the inner and outer cylinders, an intermediate cylinder crossing the reinforcing ribs, and a plurality of intermediate ribs connecting the outer cylinder and the intermediate cylinder in such a manner that at least one intermediate rib is disposed between adjacent reinforcing ribs. The reel may be molded from polyacetal plastic resin without substantial deformation in the molding process, while simultaneously attaining an improved wear resistance.

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Kanagawa, Japan

Takuzi Yamada