JPS5922310B2 - Case for magnetic tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a tape storage case (half), that is, a magnetic tape cassette, for cassette tapes, cartridge tapes, etc., used for video, audio, etc., and solves various problems caused by static electricity. The purpose is to solve the problem.

In the past, in order to avoid problems caused by static electricity generated while a magnetic tape is running, improvements have been made to magnetic tapes, such as incorporating antistatic agents into the binder of the magnetic layer and coating the back side of the tape with carbon. Even if the surface resistance of only the magnetic layer is lowered, electrostatic problems cannot be sufficiently eliminated, and even if the surface resistance is too low, problems can be seen to increase significantly. As a result, the tape becomes thick, making it impossible to record for a long time, and these tape processing methods also have the problem of being extremely expensive.

The present invention was made to solve the above-mentioned problems.
The present invention provides an inexpensive magnetic tape cassette that eliminates electrostatic troubles by improving the magnetic tape case.
Embodiments of the present invention will be specifically described below with reference to the drawings.

In Figure 1, 1 is a magnetic tape storage case (half)
, 2 is a magnetic tape, 3 is a conductive pole in contact with the back side of the magnetic tape 2 (the opposite side to the magnetic layer), 4 is a conductive pole in contact with the front surface (magnetic layer) of the magnetic tape 2, and 5 is a roller. . The poles 3 and 4 are made conductive by a method such as plating, carbon coating, or mixing a conductivity imparting agent into a polymer material, and the poles 3 and 4 are made conductive by making the case itself or the inner surface of the wall of the case conductive. It is electrically conductive through a member provided inside. The inventor discovered that electrostatic troubles could be eliminated by electrically conducting the front and back surfaces of the magnetic tape as shown in Figure 1, and as a result of further research, found that It has been confirmed that this effect is significantly exhibited when the electrical resistance is 10 8 Ω or less.

In Figure 2, the horizontal axis represents the electrical resistance between balls 3 and 4, and the vertical axis represents the level of discharge noise detected by a magnetic head with no front shield and an electrically floating permalloy core. .

As shown in FIG. 2, the discharge noise increases rapidly when the value exceeds 10 8 Ω, and decreases to a value that causes no problem in practical use below 10 8 Ω. In addition, as a result of examining the running performance of tapes with a resistance value of 108 Ω or less, we found that the running speed, h1 winding sag, and fluctuations in winding resistance due to electrostatic adhesive force.
No tape squeal or the like occurred at all. The reason for these good results is not clear, but due to the electrical coupling on both sides of the charged magnetic tape, charges move between the front and back sides of the magnetic tape, neutralizing the uneven charging on the tape surface. It is presumed that it has been removed.

In the embodiment shown in FIG. 1, a fixed conductive pole is used, but it may be made rotatable.

Furthermore, the location of these conductive poles is not limited as long as it is a tape running system within the case.
By using the magnetic tape cassette of the present invention having the above-described structure, various problems caused by static electricity can be solved.

[Brief explanation of the drawing]

FIG. 1 is an inner view of a case of a magnetic tape cassette according to the present invention, and FIG. 2 is a characteristic diagram of discharge noise versus resistance value between conductive poles in the case. 1...Magnetic tape storage case, 2...
Magnetic tape, 3, 4... Conductive pole.

Claims (1)

[Claims] 1 A conductive pole that contacts the surface of the magnetic tape and a conductive pole that contacts the back surface of the magnetic tape are provided in the tape running system in the magnetic tape storage case, and the electrical resistance between the two conductive poles is determined by the case itself or the case. A magnetic tape cassette characterized in that the resistance is set to 10^8 Ω or less by a member provided inside the cassette.