JPH06223342A - Rotary magnetic-head device - Google Patents

Abstract

PURPOSE:To obtain a rotary magnetic-head device having a structure wherein the S/N ratio of a recorded and replayed signal is not degraded and a gap in a head which records and replays a signal is not stuffed with a foreign body. CONSTITUTION:In a magnetic recording and playback apparatus, magnetic heads 21, 22 are attached to the circumference of a rotary drum 1, they come into sliding contact with a magnetic tape, and a signal is recorded and replayed. It is featured that at least one pair of opposite magnetic-tape sliding contact bodies 41, 42 are arranged at the circumference of the rotary drum 1 and that a foreign body is introduced into gaps in the sliding contact bodies.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary magnetic head device used in a VTR or the like.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus such as a VTR, a magnetic head mounted around a rotary drum is
Signals are recorded and reproduced by sliding on the magnetic tape.
Since the magnetic tape and the magnetic head come into contact with each other, abrasion powder of the magnetic tape or the magnetic head adheres to the magnetic head or is left on the magnetic tape.
It caused problems such as deterioration and dropout. As a conventional technique for solving this problem, there is a magnetic head for a rotary drum described in JP-A-3-69008. The above-mentioned prior art is devised so that a foreign matter is introduced before and after the magnetic gap on the tape sliding surface of the magnetic head so that the foreign matter is not blocked on the magnetic gap.

[0003]

However, in the above-mentioned prior art, in order to form a step on the tape sliding contact surface of the magnetic head for recording and reproducing signals, the magnetic head is formed on the magnetic head when the rotary drum is rotated. Due to the step, the flow of the air layer on the magnetic head is disturbed, the spacing between the head tapes is increased, and the S / N for recording / reproducing signals is reduced. In addition, after the foreign matter fills the concave portion, the effect of removing the foreign matter is significantly reduced, and conversely, the accumulated foreign matter is left behind on the magnetic tape, causing a problem of dropout. It was

An object of the present invention is to record and reproduce signals.
Another object of the present invention is to provide a rotary magnetic head device having a structure in which foreign matter does not clog the gap of the head for recording / reproducing a signal without causing deterioration of / N.

[0005]

SUMMARY OF THE INVENTION The above-mentioned object is to dispose at least a pair of facing magnetic tape sliding contact bodies around a rotating drum separately from a head for recording / reproducing a signal, and a foreign substance in a gap between the sliding contact bodies. This is achieved by adopting a structure that introduces.

[0006]

In addition to the head for recording / reproducing signals, a magnetic tape sliding contact body for removing foreign matter is provided on the rotating drum.
Even if the rotary drum is rotated, the air layer on the head for recording / reproducing signals is not disturbed. Therefore, the spacing between the magnetic head and the magnetic tape does not increase, so the signal S
/ N does not deteriorate. Further, since the foreign matter is stored between the pair of magnetic tape sliding contact bodies facing each other and is not filled with the foreign matter like a concave portion, the foreign matter is not clogged on the magnetic gap surface.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment using the present invention is shown in FIGS. On the rotating drum (1), the magnetic heads (21), (2
2) is installed at an angle of about 180 degrees. A pair of tape sliding bodies (41) and (42) are provided on the rotary drum at an angle approximately in the middle of the magnetic head. FIG. 2 shows that the magnetic heads (21), (22) and the tape sliding contact body (41) during one rotation of the rotary drum,
It is the figure which showed the track on the magnetic tape which (42) scans. The magnetic heads (21) and (22) scan predetermined tracks (31) and (32) respectively, and the tape sliding contact bodies (41) and (42) have the magnetic heads track (31) and (32). Prior to scanning (32), on track (33), the height above the rotating drum to scan,
The sliding contact width is selected. The present inventor has found that the magnetic head (2
A metal / ferrite composite head was used for 1) and (22), and a single crystal ferrite material was used for the tape sliding contact bodies (41) and (42). This is because the wear rate of the metal / ferrite composite head is mainly determined by the ferrite material, and the wear rate of the tape sliding contact bodies (41) and (42) is set to the wear rate of the magnetic head by selecting the ferrite crystal orientation. After the tape is run for a long time, the magnetic heads (21) and (22) and the tape sliding contact bodies (41) and (4) can be combined.
This is because the relative value of the amount of protrusion from the rotating drum of 2) can be maintained and a predetermined effect can be obtained even after the tape has been running for a long time. The distance between a pair of facing sliding bodies is 0.05 m
Although the value was changed from m to 1 mm, there was no difference in the obtained effect. Further, the sliding surface of the tape sliding contact body was lapped in the same manner as the magnetic head, so that the tape had a shape easily adapted to the magnetic tape. The foreign matter generated by the running of the magnetic tape or existing on the tape is before the magnetic head scans the track on which the foreign matter exists.
1) and (42) run on the truck and accumulate foreign matter in the gap. Therefore, since the magnetic head never contacts the foreign matter, the foreign matter is not clogged in the gap between the magnetic heads (21) and (22), and the S / N ratio of the signal to be recorded / reproduced is reduced.
Will not deteriorate.

FIG. 4 shows a second embodiment of the present invention. The present invention is an embodiment in which at least one of the tape sliding contact members is a rotary erasing head. Erase head
Since the influence of the spacing between the magnetic tape and the head is relatively small, the foreign matter can be stored in the gap without adversely affecting the erasing operation even if the foreign matter is stored and the spacing is generated between the magnetic tape and the head. In the present embodiment, it is not necessary to mount a tape sliding contact member on the rotary drum in addition to the magnetic head required in the system, so there is also an effect that the size is reduced and the number of steps is not increased.

[0009]

According to the present invention, a magnetic tape sliding member for removing foreign matter is provided on the rotating drum in addition to the head for recording / reproducing signals, so that the recording / reproducing of signals is performed even when the rotating drum is rotated. The air layer on the head is not disturbed. For this reason, the spacing between the magnetic head and the magnetic tape does not increase, so that signal S / N deterioration does not occur. In addition, foreign matter is stored between a pair of magnetic tape sliding contact members facing each other,
Since the foreign matter is not filled with the foreign matter like the concave portion, the foreign matter is not clogged with the magnetic gap surface.

[Brief description of drawings]

FIG. 1 is a schematic view showing a rotary magnetic head device of the present invention.

FIG. 2 is an explanatory diagram of a scanning position relationship on the tape of the present invention.

FIG. 3 is a perspective view showing a tape sliding contact body according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing a tape sliding contact body according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rotary drum, 21, 22 ... Magnetic head, 3 ... Magnetic tape, 41, 42 ... Tape sliding contact body.

Claims (3)

[Claims] 1. A magnetic head (2) is mounted around a rotary drum (1) and slidably contacts a magnetic tape (3),
In a magnetic recording / reproducing apparatus for recording / reproducing signals, at least a pair of magnetic tape sliding contact bodies (4) facing each other are arranged around the rotary drum so as to slide in advance on a tape track on which the magnetic head runs. The rotary magnetic head device is characterized in that foreign matter is introduced into the gap between the sliding contact bodies. 2. A magnetic tape sliding contact body (4), at least one of which is an erasing head.
The rotating magnetic head device described. 3. The magnetic tape sliding contact width of the magnetic tape sliding contact body (4) is larger than the magnetic tape sliding contact width of the magnetic head (2). Rotating magnetic head device.