JPH073687B2 - Multi-pole magnetized erasing head - Google Patents

Description

TECHNICAL FIELD The present invention relates to a multi-pole magnetized erasing head in which up to a plurality of sets of NS bipolar poles are magnetized in order to erase the contents recorded on a magnetic tape.

(Prior Art) Conventionally, in this type of multi-pole magnetized erasing head, only a plurality of pairs of NS poles are magnetized on all of the tape sliding arc fronts corresponding to the tracks to be erased on the magnetic tape. Front multi-pole / side non-magnetized type (see Fig. 3), NS of both poles magnetized and tape provided on all of the tape sliding arc-shaped fronts corresponding to the tracks to be erased on the magnetic tape Front multi-pole with magnetizing auxiliary poles provided only on the side of the entry side
Side-magnetized type (see JP-A-57-150105)
Is known.

(Problems to be Solved by the Invention) The former described in the above-mentioned conventional technique has an unfavorable defect that the stop noise at the time of recording becomes large when Gaussian is increased to improve the erasing rate (see FIG. 4).
In order to solve this, a trader is aware of the decrease in the erasing rate and employs a means for suppressing the stop noise by reducing the Gaussian as shown in FIG.

In the latter, the auxiliary pole is magnetized only on the side surface of the tape on the entry side, thereby improving the erasing rate and not improving the stop noise.

Furthermore, since the front and the latter do not have auxiliary poles on the side of the exit side, the residual magnetism due to the magnetic force of the final pole near the tape exit side in front multipole magnetization was relatively large, and there was much erasing noise.

It is an object of the present invention to provide a novel multi-pole magnetized erasing head which has low stop noise and erasing noise during recording.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present multi-pole magnetized erasing head has a plurality of NS poles at a position facing a track to be erased of a magnetic tape on a tape sliding arc-shaped front surface. In a multi-pole magnetized erasing head having a multi-pole front magnetized portion magnetized up to a set, the same pole as the last pole of the front magnetized portion is located on the side of the tape exit side near the tape sliding arc front. Of the front side is attached to the exit side magnetized portion formed by providing the magnetic tape in a state in which the magnetic tape runs in the magnetic field of the magnetisation, and the side of the tape entrance side near the tape sliding arc-shaped front surface. The magnetic pole has a magnetic pole different from the first pole, and the magnetic tape is provided in a state in which the magnetic tape travels in the magnetic field of the magnetic polarization.

(Embodiment) In the embodiment of the present invention shown in FIGS. 1 and 2, multiple sets of NS poles are alternately magnetized on a tape sliding arc-shaped front surface 1 at a position facing a track to be erased of a magnetic tape. The magnetic tape is magnetized to the front magnetized portion 2 of the pole and to the side surface 3 on the tape exit side near the tape sliding arc-shaped front surface 1 to the same pole as the last pole of the front magnetized portion 2. The exit side magnetized portions 4 are formed by traveling in a magnetic field, and the side surface 6 on the tape entry side has a pole different from the first pole of the front magnetized portion at a position near the tape sliding arc-shaped front surface 1. The entry side magnetized portion 5 is formed by providing the magnetized state with the magnetic pole tape 7 running in the magnetic field of the magnetized portion.

(Operation) Since the approach magnetizing part 5 provided on the side surface on the tape entering side improves the erasing rate, the Gauss of the front multi-pole magnetizing should be reduced by this amount (see Fig. 5 and 6). It becomes possible to reduce the stop noise by the amount of the reduction of the magnetic field. Also, the conventional type shown in FIG. 3 which does not have the exit side magnetizing part has the part indicated by the white arrow in the figure.
The magnetic force of N100 gauss becomes residual magnetism when the tape is separated, but the exit side magnetized portion 4 provided on the side surface 3 on the tape exit side in the present invention is indicated by a white arrow in the figure. The residual magnetism due to is made close to zero and the erase noise is reduced.

(Advantages of the Invention) Since the present invention has the above-described configuration, as is clear from the description of the above-mentioned operation, a novel multi-pole magnetized erasing head with both stop noise and erasing noise during recording is small. It has an excellent effect of being able to completely achieve the intended purpose of providing.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a multi-pole magnetized erasing head of the present invention, FIG. 2 is a Gaussian curve diagram showing the same as the magnetized portion, and FIG. 3 is a conventional front multi-pole. Fig. 4 is a Gaussian curve diagram showing a state corresponding to a magnetized portion of a side-magnetization-free erasing head, Fig. 4 is a magnetic force generation state explanatory diagram showing a conventional multi-pole magnetized erasing head having a large Gauss, and Fig. 5 is FIG. 6 is a diagram for explaining a magnetic force generation state of a conventional multi-pole magnetized erasing head with a reduced Gauss, and FIG. 6 is a diagram for explaining a magnetic force generation state of the multi-pole magnetized erasing head of the present invention. 1 ... Tape sliding arc front, 2 ... Front magnetized part, 3 ...
Side surface, 4 ... exit side magnetized part, 5 ... entry side magnetized part.

Claims (1)

[Claims] 1. A multi-pole magnetized erasing head having a multi-pole front magnetized portion magnetized to a plurality of sets of NS both poles at a position facing a track to be erased of a magnetic tape on a tape sliding arc-shaped front surface. In the above, by providing the magnetization of the same pole as the last pole of the front magnetized portion at a location near the tape sliding arc-shaped front surface of the tape exit side in a state where the magnetic tape runs in the magnetic field of the magnetization. The exit side magnetizing part formed and a part of the side surface on the tape entering side near the tape sliding arc-shaped front face are magnetized with a pole different from the first pole of the front side magnetizing part in the magnetic field of the magnetisation. A multi-pole magnetized erasing head having an entrance side magnetizing portion formed by being provided in a traveling state.