Reel of magnetic tape cartridge

Abstract

A reel (2) of a magnetic tape cartridge (1) which is rotatably housed in a cartridge case (3) and on which a magnetic tape is wound, wherein a magnet attracting in a reel bottom wall (21a), where the centre hole (25a) a metal plate (25) is integrally insert-molded on the bottom face, the metal plate (25) is formed into an annular shape having a center hole (25a), and, at the insert-molding time, a resin is injected from the gate at the center portion of the center hole (25a) of the metal plate (25) to form a recess (21b) of the metal plate (25) is sealed with the resin, at a portion between the gate trace (21c) of the center portion and the inner circumference of the center hole (25a) of the metal plate (25).

Description

[0001] This application is a divisional application, the application number of its parent application is: 99813260.8, the application date: 1999.11.11, the invention name: tape cassette control tape reel. technical field [0002] The invention relates to a magnetic tape cassette control reel in which a single control reel on which a magnetic tape is wound is accommodated in a magnetic tape cassette shell and rotatable. Background technique [0003] Conventionally, in a magnetic tape cassette used as a storage medium for an external storage device such as a computer, it has been known to wind a magnetic tape on a single control reel, then house the control reel in a cassette case and use it The type that can rotate. This tape is used to store data on a computer, etc. Since it contains important information, it is necessary to prevent the tape from jamming and other failures, and to prevent the tape from being accidentally pulled out when it is not in use, such as for storage....

AI Technical Summary

Problems solved by technology

[0005] However, when the metal plate is fixed on the tape control reel, although the metal plate is placed on the inner surface of the metal mold to make it integrated with the tape control reel in the form of insert molding, it is relatively easy to implement in manufacture. However, when insert molding is performed by injecting molten resin from the gate of the central part of the central hole of the circular metal plate, the resin flowing in under high pressure directly acts on the inner peripheral surface of the central hole of the metal plate, which may be caused by resin intrusion. Between the metal plate and the inner surface of the metal mold, it is impossible to fix the metal plate on the given position of the tape control reel

Also, with the intrusion of the resin, when the resin surrounds and enters the tape control reel molded product on the surface side of the metal plate, the following problems may occur: that is, since the metal plate and the rotational drive member on the driving side cannot be ensured, the following problems may occur. The problem of not being able to clamp due to the planarity of the magnet

[0006] If the injection pressure is lowered to prevent the resin intrusion, there will be a problem that the dimensional accuracy of the molded product will be lowered due to the generation of poorly filled resin parts.

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