JPH06251345A - Magnetic head drum - Google Patents

Abstract

PURPOSE:To-immediate reproduction of recorded data by disposing a recording head and a reproducing head while spacining apart by a predetermined distance in the axial direction. CONSTITUTION:In a magnetic head drum comprising recording heads A1, A2 and reproducing heads B1, B2, inclining in the running direction of a magnetic tape, and coming into contact therewith while rotating, the recording heads A1, A2 and the reproducing heads B1, B2 are disposed while being spaced apart by a predetermined distance L in the axial direction of the drum. When the magnetic drum is constituted of upper, intermediate, and lower drums 11, 12, 13 and the recording heads A1, A2 are spaced apart by a predetermined distance L from the reproducing heads B1, B2, a reproducing head passes on a track on which the magnetic tape has passed in a predetermined recording head and thereby the recorded data can be reproduced immediately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head drum and, more particularly, to a technique for allowing a reproducing head to immediately reproduce data after recording on a magnetic tape.

[0002]

2. Description of the Related Art Conventionally, a magnetic head drum of a helical scan type having a recording / reproducing head, such as an 8 mm VTR and a DAT, has been known. In FIG. 9 showing a conventional magnetic head drum 1, two magnetic heads X and Y having a recording head and a reproducing head adjacent to each other are located at, for example, 220 to 230 ° with respect to the center of the magnetic head drum 1. It is installed in.

Next, the operation will be described. Magnetic tape (hereafter
When recording / reproducing to / from a tape 2), the tape 2 is conveyed in the right direction in the figure, for example. And magnetic head drum 1
Is inclined with respect to the transport direction of the tape 2 and is rotated in the same direction as the running direction of the tape 2 (the direction of the arrow in the figure) in order to increase the relative speed with the tape 2. For example, the magnetic head drum 1 is rotated at a rotation speed of 1800 rpm in order to set the relative speed to the tape 2 to 3.8 m / sec. As a result, the magnetic heads X and Y cross diagonally with respect to the running direction of the tape 2. For example, when the magnetic head X passes over the track a from the head entrance point on the tape 2 and leaves the tape 2 at the head exit point, this time. The magnetic head Y contacts the magnetic tape 2 at the head entry point of the next track and similarly passes to the head exit point.

In this manner, the two magnetic heads X and Y perform recording and reproducing one track at a time, and two tracks form one screen of information. The magnetic head drum 1 is also used in an inspection device, and by reproducing and outputting the signals recorded by the magnetic heads X and Y, the output characteristics, C / N, S / N, defect detection, etc. The characteristics of the tape 2 such as noise measurement, and the dropout where the reproduction signal is lost due to scratches on the tape surface or adhesion of foreign matter are inspected by this inspection device.

[0005]

In the conventional magnetic head drum, since the magnetic heads X and Y are recording / reproducing heads, when the data recorded by the magnetic head X is immediately reproduced by the magnetic head X, for example. , Crosstalk may occur. Therefore, once recording is performed with the magnetic head X, the track is rewound and the recorded track is recorded with the magnetic head X.
Since the recorded data cannot be immediately reproduced and the magnetic head drum 1 is used in the inspection device, the magnetic head drum 1 must be rewound once. Was taking time.

Further, since the recording and reproducing heads are arranged in a line in the cylinder rotation direction, there is always a time delay, that is, off-track, in the trace of the recorded track. Therefore, the reproducing head is moved up and down to turn off-track. However, the conventional method has a disadvantage that the full surface inspection cannot be performed when the above is corrected. The present invention has been made in view of such conventional problems, and an object thereof is to provide a magnetic head capable of immediately reproducing data recorded on a magnetic tape.

[0007]

Therefore, the present invention is provided with at least one set of recording head and reproducing head, is inclined with respect to the traveling direction of the traveling magnetic tape, and contacts the magnetic tape while rotating. In the magnetic head drum, the recording head and the reproducing head are arranged so as to be separated from each other by a predetermined distance in the axial direction of the drum.

[0008]

According to the above structure, if the predetermined distance between the recording head and the reproducing head is set, the reproducing head passes through the track on which the magnetic tape has passed by the predetermined recording head, and the recorded data is immediately transmitted. Can be played. If this magnetic head drum is used in a magnetic tape inspection device, the characteristics of the magnetic tape can be inspected at high speed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 7 shows a magnetic head drum 10 of this embodiment having two recording heads and two reproducing heads. The magnetic head drum 10 is, for example, 8 mm VT.
It is used not only for R, DAT, etc., but also for inspection devices that inspect the characteristics of magnetic tape. The magnetic head drum 10, the recording head A ₁ and the read head B ₁ represents, are arranged apart in the axial direction of the magnetic head drum 10 as crosstalk will not occur by a distance L, the recording head A ₂ The reproducing head B _{2 is} also arranged in the same manner.

The magnetic head drum 10 is composed of an upper drum 11, a middle drum 12, and a lower drum 13, as shown in FIG. 1, for example. The upper drum 11 and the middle drum 12 each have a hole 11 at the center.
The lower drum is a cylindrical object provided with a and 12a.
Reference numeral 13 denotes a columnar object having columns 13a which are inserted into the holes 11a and 12a of the upper drum 11 and the middle drum 12. The recording heads A ₁ and A ₂ are attached, for example, at a predetermined angle with respect to the center of the upper drum 11, and their tips are positioned at the outer peripheral surface of the upper drum 11. Further, the upper drum 11 is provided with a protrusion 11b at a predetermined position.

A recess 12b and notches 12c and 12d are provided on the upper surface of the middle drum 12, and the positions of the notches 12c and 12d are determined when the protrusion 11b of the upper drum 11 is inserted into the recess 12b. The recording heads A ₁ and A ₂ are located at positions corresponding to the recording heads A ₁ and A ₂ so as not to come into contact with the upper drum 11. The reproducing heads B ₁ and B ₂ are attached to the lower surface of the middle drum 12, and the tips of the heads come to the positions of the outer peripheral surface of the middle drum 12.

To assemble the drums shown in FIG. 2 (A) as shown in FIG. 2 (B), the protrusion 11b of the upper drum 11 should be the middle drum.
It is inserted into the recess 12b of 12 and the column 13a of the lower drum 13 is inserted into the hole 11a of the upper drum 11 and the hole 12a of the middle drum 12. When assembled, the upper drum 11 and the middle drum 12 can rotate at a predetermined same speed without slipping with respect to the lower drum 13.
₁ and 2, the recording head A ₁ and the reproducing head B ₁ ,
The recording head A ₂ and the reproducing head B ₂ are magnetic head drums.
The magnetic head drum 10 is arranged on the circumference of the circle 10 in parallel with the axis of the magnetic head drum 10. However, the magnetic head drum 10 may be arranged so as to be displaced in the circumferential direction from this position.

Next, an example of the positional relationship for causing the reproducing heads B ₁ and B ₂ to immediately reproduce the data recorded on the tape 20 by the recording heads A ₁ and A ₂ will be described. First, the parameters necessary for calculating the positional relationship are as follows, and these parameters are the perspective view of the magnetic head drum 10 in FIG. 3, and the plan view for explaining the positional relationship of the magnetic heads in FIG. 5 is an explanatory view of the tape shown in FIG.

Drum rotation speed r [rps] Drum diameter R [m] Relative speed between media and magnetic head V_H[M / s] Vertical distance between recording head and reproducing head L [m] Angle formed by recording head and reproducing head θ [degree] Number of heads n [pieces] Tape winding angle ψ [degree] Tape speed v [M / s] Track inclination angle φ [degree] In FIG._nRecord with (n = 1 or 2)
Playback head B_nTo trace with
Is the recording head A_nThe recording section recorded in (for example, x ₁point)
But playback head B_nOn the trace line (eg x
₂B) when reaching point _nIs for example x₂It is good if it exists at the point
Yes.

[0015] T points x ₁ reaches point x ₂ times, the distance between the points x _1, x ₂ as _{y 1, T = y 1 /} v = (1 / v) · (L / sin φ). ． ． (1) Further, the relative velocity V _H between the medium and the magnetic head is V _H = πRr, and the relative position y ′ between the recording head A _n and the reproducing head B _n is y ′ = πR · (θ / 360). ． ． (2) Therefore, the time t at which the reproducing head B _n reaches the point x ₂ is t = (y ₂ / V _H ) = (1 / πRr)  (L / tan φ-πRθ / 360) = (1 / r ) · {L / (πRtan φ) −θ / 360}. ． ． (3) However, the conditions of this case, since the recording head A _n is not be reproduced and the reproduction head B _n at present in _one point x exists above the _two points x, than y _2> 0 theta As (L
/ Tan φ-πR · θ / 360)> 0 is required.

Expression (3) is the time t when the reproducing head B _n reproduces immediately after recording with the recording head A _n . For example, the data recorded by the recording head A ₁ is reproduced by the reproducing head B ₂
When playing with, or B ₁ or B ₂ after N rotations
When playing with, it becomes as follows. t = 1 / (πRr) {L / tan φ−πR · θ / 360 + 1/2 (πRN)} = 1 / r {L / (πRtan φ) + (180 · N−θ) / 360} (however, N = 0, 1, 2, ... N). ． ． (4) Therefore, in order to satisfy the above condition, T = t. ． ． (5) Substituting equations (1) and (4) into this equation (5), ∴L {1 / (v · sin φ) −1 / (rπRtan φ)} = (180 · N−θ) / (360 · r) (However, N = 0, 1, 2, ... N). ． ． (6) The positional relationship between the recording heads A ₁ and A ₂ and the reproducing heads B ₁ and B ₂ may be calculated based on this equation (6).

Next, the operation will be described. If each parameter is set based on the equation (6), for example, the reproducing head B ₁ or B ₂ traces the track passed by the recording head A ₁ , and the data recorded on the tape 20 by the recording head is Played by the playhead immediately. For example, if the magnetic head drum 10 is used in a tape inspection device, it can be reproduced immediately after recording without rewinding, and tape characteristics such as output characteristics, C / N, S / N, defect detection, and noise measurement. , Dropout, etc. are inspected at a level close to the actual machine.

According to this structure, by disposing the recording head and the reproducing head apart from each other in the axial direction of the magnetic head drum 10, the track recorded by the recording head can be immediately traced and reproduced by the reproducing head. Can be done. Therefore, if this magnetic head drum 10 is used in a tape inspection device, there is no need to rewind after recording, so the inspection can be speeded up at a level close to that of the actual machine,
When used in a VTR of VHS, 8 mm, DAT, etc., recording can be performed while monitoring the recording signal, as in the case of the 3-head system in the so-called cassette deck for music.

In this embodiment, two recording heads and two reproducing heads are arranged, but the present invention is not limited to this, and it is also possible to arrange three or more recording heads and reproducing heads in the circumferential direction. Yes, if the multiple heads are used in this way, the inspection can be further speeded up. Further, the magnetic heads may be stacked in four stages or more. For example, as shown in FIG. 8, when the magnetic heads are stacked in four stages, the magnetic head drums 30 are composed of an upper drum 31 and a first middle drum from the top in the figure.
5 of 32, second middle drum 33, third middle drum 34, and lower drum 35
The recording heads A ₁₁ and A ₁₂ and the reproducing heads B ₁₁ and B ₁₂ are arranged in the axial direction of the magnetic head drum 30.
It is interposed between each drum. Even with this configuration, multi-heading can be achieved.

[0020]

As described above, according to the present invention, the track recorded by the recording head can be immediately traced by the reproducing head by disposing the recording head and the reproducing head separately in the vertical direction. . If such a magnetic head drum is used in a magnetic tape inspection device, the inspection speed can be increased to a level closer to that of an actual machine.
If used for R, recording can be performed while monitoring the recording signal. .

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a magnetic head drum according to an embodiment of the present invention.

FIG. 2 is an assembly diagram of a magnetic head drum.

FIG. 3 is a perspective view of FIG.

FIG. 4 is an explanatory diagram of a positional relationship of magnetic heads.

FIG. 5 is an explanatory diagram of a positional relationship of magnetic heads.

FIG. 6 is an explanatory diagram of a magnetic tape.

FIG. 7 is an explanatory diagram of a positional relationship between a magnetic tape and a magnetic head.

FIG. 8 is a diagram showing a configuration of a drum of a magnetic head according to another embodiment of the present invention.

FIG. 9 is an explanatory diagram of a conventional magnetic head drum.

[Explanation of symbols]

10, 30 Magnetic head drum 11, 31 Upper drum 12, 32, 33, 34 Middle drum 13, 35 Lower drum 20 Magnetic tape A ₁ , A ₂ , A ₁₁ , A ₁₂ Recording head B ₁ , B ₂ B ₁₁ , B ₁₂ playhead

Claims (1)

[Claims] 1. A magnetic head drum, comprising at least one set of a recording head and a reproducing head, tilting with respect to a traveling direction of a traveling magnetic tape and contacting the magnetic tape while rotating, the recording head and the reproducing head. A magnetic head drum, characterized in that the head and the head are arranged apart from each other by a predetermined distance in the axial direction of the drum.