Abstract: A tape cartridge which comprises a cartridge case made of a complex plastic material made of polyolefin resin, mixed with a filler of 45 percent to 65 percent by weight of the plastic material wherein the filler includes particles made of at least one of calcium carbonate and barium sulfate. The tape cartridge has a dynamic loss of more than 1.times.10.sup.9 dyne/cm.sup.2 within a range of oscillation frequency of 0.1 Hz to 1000 Hz. Accordingly, the tape cartridge of the present invention can prevent a running tape arranged in the tape cartridge from oscillating since outside oscillation is attenuated in the tape cartridge. Also the tape cartridge can reduce modulation noise which occurs because of the outside oscillation.

Abstract: A tape cartridge of the type having a pocket for drawing out a recording tape from the cartridge for tape loading and a shutter slidably mounted on the bottom portion of the cartridge for opening and closing the bottom opening of the pocket, and a plurality of ribs extending in a frontward and backward direction on the inner face of the shutter so as to assure a smooth sliding movement of the shutter.

Abstract: In a tape cartridge comprising a case body having an opening for viewing the amount of roll of tape, at least one hub accommodated in the case body for winding a recording tape, a plate for closing the opening and a braking member for stopping rotation of the hub when not in use, the plate is composed of a support plate and a transparent window plate portion and is assembled in the case body defining a gap g between the support plate and the inner face of the top wall of the case body. The brake member is slidably inserted in the gap g with a part of the brake member engaging a part of the hub to stop rotation thereof.