JPH02210651A - Head drum for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable the lower end of a magnetic tape to be attracted to a magnetic head side at a magnetic tape entering point and to secure stable head touch capability even under low tape tension by providing a notched aperture at the magnetic tape approach point at the outer periphery of a fixed drum. CONSTITUTION:A magnetic head 3(3') is mounted at the prescribed position of a notched part 25 provided at a rotary drum part 2 at a state where it is protruded by a prescribed quantity from the outer periphery of the drum part 2. Also, a notched part 26 is provided at the position where the magnetic head 3(3') is started to be abutted with the magnetic tape 1 on a fixed drum part 4. The air rolled in by the rotation of the rotary drum part 2 in a direction of arrow head A is escaped passing a groove 27 at the outer periphery of the rotary drum part 2, and also, it flows in to the notched parts 25 and 26. Thereby, since a part shown in oblique line becomes a negative pressure are for outside air pressure, the magnetic tape 1 is attracted in the directions of the rotary drum part 2 and the fixed drum part 4, which holds the abutting state of the magnetic tape 1 for the magnetic head 3(3') satisfactorily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing device, and particularly to a head drum shape suitable for ensuring head touch performance at the tape entry point of the head drum.

[Conventional technology]

General K. The head drum of a magnetic recording and reproducing device that records and reproduces video and audio signals by pulling out a magnetic tape from a cassette and wrapping it around a drum containing a magnetic head at a predetermined angle, extends a predetermined amount in the radial direction from its outer circumference. (20~50μ
m) A rotating drum part with a magnetic head mounted on a protruding state, which rotates at a frequency of 30 Hz with the drum center axis as the center axis of rotation, and a rotating drum part having approximately the same diameter as this rotating drum part and relative to the rotating shaft of the magnetic head. A fixed drum part has a step (lead) on its outer circumferential surface that regulates the bottom edge of the magnetic tape so that the magnetic tape forms a predetermined inclination angle and signal tracks are recorded diagonally on the magnetic tape, and a rotating drum. and a directly connected motor section.

Here, recording and reproducing of the signal track is carried out by running the magnetic tape spirally mounted at a predetermined angle as described above at a constant speed (by a capstan motor), so that the head and the tape come into contact at a predetermined position. This is done by performing a head or helical scan over the tape.

In recent years, the recording density, the amount of signals recorded per unit area on magnetic tape, has continued to increase.As the wavelength of signals has become shorter, the signal recording area on magnetic tape has expanded. Signals are now being recorded to the limits of magnetic tape edges. In such a case,
The state of contact between the tape and the head at the lower edge of the magnetic tape is as shown in FIGS. 7 and 8. The head 3 is largely warped in a direction away from the fixed drum 4, and a spacing occurs in which the contact area in the lower half of the magnetic head 3 in the thickness direction R (radius) is small. As a result, as shown in FIG. 9, in the output waveform 5 of the video and audio signals, the front end tends to suffer from output deterioration. It has been experimentally confirmed that this phenomenon becomes more pronounced as the widthwise rigidity of the magnetic tape increases.

In order to avoid the above phenomenon, it is generally done by increasing the tension of the magnetic tape 1 or forcibly twisting the magnetic tape 1. Also, JP-A-62-10
As described in Japanese Patent No. 9250, a member for attracting the magnetic tape 1 toward the magnetic head 3 is provided near the magnetic head 5.

[Problem to be solved by the invention]

However, if conventional methods such as increasing the magnetic tape tension and deforming the tape as described above are used, they will accelerate the wear of the magnetic head and shorten the life of the magnetic head. During contact and sliding, the magnetic tape is likely to be damaged, causing problems such as a significant decrease in the reliability of the device.

In addition, when attaching a tapered pad member to attract the tape to the magnetic head, the tapered pad member does not have to be used, which makes head attachment work such as protrusion amount adjustment, posture adjustment, level difference adjustment, etc. extremely complicated and difficult. This increases the installation process and causes problems such as high costs.

In view of the above-mentioned problems, the present invention makes it possible to attract the lower end of a magnetic tape toward the magnetic head at the tape entry point of the head drum without adding any new members and without changing the head mounting operation. The present invention provides a head drum shape that allows stable head touch performance even under low tape tension.

[Means to solve the problem]

In order to achieve the above object, in the head drum of the present invention, a cutout opening structure is provided at the magnetic tape entry point on the outer periphery of the fixed drum.

[Effect]

In the notch opening provided in the fixed drum, the air caught between the magnetic tape and the rotating drum due to the rotation of the rotating drum flows into the notch on the circumference of the rotating drum for attaching the magnetic head, and It also flows into the notch of the stationary drum.

Therefore, the notch becomes a negative pressure region compared to the outside pressure, and the lower edge of the magnetic tape is drawn toward the fixed drum at the notch on the fixed drum. Therefore, the spacing between the lower part of the magnetic head and the magnetic tape is eliminated, and the magnetic head is brought into complete contact with the magnetic tape. Furthermore, since it is not necessary to set the tape tension high, the life of the magnetic head can be extended, and damage to the tape due to high tension can be prevented.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and operation of an embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 3 shows a schematic plan view of a magnetic recording/reproducing apparatus equipped with the heradora 4 of the present invention in a fully loaded state. The outline of the entire device will be explained using this figure.

The magnetic tape 1 is supplied from a supply reel 7 in a cassette 6 (double-dashed line) to a tension run pin 8 and an entry side inclined pin 10 erected on a guide base 9 . No. 2 on the approach side, which was also planted.
The magnetic tape 1 passes through the guide roller 11 and the first guide roller 15 on the entry side, which is set up on the guide base 12, and is wound around the head drum 14 at a predetermined angle (226@), and then exits the head drum 14. Exit side inclined pin 16 planted in 15. Similarly, the contents of the cassette 6 pass through the ejection side guide roller 17, the pinch roller 18, the capstan 19, and the ejection side height regulation guide 20, and are driven at a constant speed by the capstan 19 and the pinch roller 18. It is wound up on a take-up reel 21. During this time,
Signals are recorded or reproduced on the magnetic tape 1 by magnetic heads 3, which are attached to the head drum 14 at 180° opposite to the head drum 14.

FIG. 4 schematically shows a front view of the head drum 14 with the magnetic tape 1 mounted thereon.
, a signal writing operation by a magnetic head to a magnetic tape will be explained.

The head drum 14 has a predetermined amount (20 to 5 Q
txa) At least two magnetic helads 3, 3' are mounted on the tower in a protruding state, and the center axis of the drum is used as the center axis of rotation,
It has a rotary drum section 2 that rotates in the direction of arrow A at a frequency of 30 Hz and a rotary transformer (not shown), and the magnetic tape 1 forms a predetermined inclination angle with respect to the rotation axis of the magnetic helads 3 and 3'. It is composed of a fixed drum section 4 having a step (lead) 22 on its outer circumferential surface for guiding the lower end of the magnetic tape 1, and a motor section 23 directly connected to the rotating drum section 2 so that it can run. ing.

Here, the magnetic tape 1 is placed on the fixed drum section 4.
The magnetic tape 1 runs so that its lower end is along the magnetic tape 22.
The head drum 14 is mounted on the cassette substrate so as to be inclined by an angle α in the figure with respect to the 0-travel direction arrow B. In this state, the magnetic heads 3 and 3' attached oppositely by 180 inches trace the magnetic tape 1, and signals are sequentially recorded.

FIG. 5 shows a portion 24 of the signal track pattern recorded on the magnetic tape 1 by the above operation. This embodiment is a system in which a digital audio signal track z4(b) (hatched in the figure) is recorded on the extension of the video signal track 24(a) (at the bottom edge of the magnetic tape 1),
The height L to the end of the digital audio signal track is approximately CL5
5~(approximately 17mm).

Next, the effect of improving head touch according to the present invention will be explained with reference to FIGS. 1 and 2.

FIG. 1 shows a magnetic head 3. (A plan view showing the state of tape and head contact at the entry point of 3). Figure 5 is a sectional view of Figure 4. In both figures, the same parts are designated by the same reference numerals. .

The magnetic heads 3 and (3') are mounted at predetermined positions in the notches 25 provided in the rotary drum part 2, with the heads protruding by a predetermined distance 1 (20 to 50 μm) from the outer circumference of the rotary drum part 2. I'm getting lost. Moreover, the magnetic head 3. At position K where (3') starts contacting the magnetic tape 1, a notch 26 is provided on the fixed drum portion 4 as shown.

Here, the air drawn in by the rotation of the rotating drum section 2 in the direction of arrow A escapes through the grooves 27 provided on the outer periphery of the rotating drum section 2, as well as through the notches 25 and 26.
flows into. Therefore, the shaded area in the figure becomes a negative pressure area with respect to the external pressure, and therefore, as shown in FIG. The spacing between the head and the tape at the bottom of the magnetic head, which conventionally occurred, is eliminated, and the magnetic tape 1 is attracted toward the magnetic heads 3 and (3'). Good contact condition is maintained.

As a result, as shown in FIG. 6, the output deterioration (FM drop) that occurred at the front end of the reproduced output waveform 5 of the audio and video signals is improved, and it is possible to obtain a good reproduced output waveform. I can do it.

As described above, according to this embodiment, it is possible to eliminate the spacing that tends to occur below the magnetic head at the magnetic tape entry point in the head drum, and it is possible to obtain a good reproduced output waveform.

As a result, it is possible to prevent noise occurring at the top of the screen, vertical synchronization loss, and loss of digital audio.

〔Effect of the invention〕

According to the present invention, it is possible to eliminate the spacing that occurs at the bottom of the magnetic head at the point where the magnetic tape enters the head drum, so that a good contact condition between the head and the 7'' tap can be maintained, and noise at the top of the screen can be reduced. This prevents loss of synchronization, loss of audio, etc.Furthermore, since there is no need to set the tape tension higher than necessary, it is possible to suppress wear on the magnetic head and extend the life of the head. It also has the effect of preventing

[Brief explanation of the drawing]

FIG. 3 is a schematic plan view of a magnetic recording and reproducing apparatus equipped with a head drum according to an embodiment of the present invention, FIG. 4 is a front view of the head drum with a magnetic tape mounted thereon, and FIG. is the signal track pattern i recorded on the magnetic tape, the first
The figure shows the tape at the entrance point of the magnetic tape to the head drum of the present invention. 1... Magnetic tape, 2... Rotating drum, s, 3... Magnetic head, 4... Fixed drum, 25
... Rotating drum notch, 26... Fixed drum notch opening. Frozen 25 --- FEJk Dohiro to sword cutter 14 --- 7th floor lower ram (ase; direction diagram ko --- gift number tiger 77: 24 (Q) -- Tsushakui kakui head number. Ratsuf? #b) --
7/F ILa/')7'/F No. z---(5 seasons IF Ram 4-m-Fixed drum 5--One day, Audio Pr raw output) term (obedience)

Claims (1)

[Claims] 1. A cylindrical cylinder on which a plurality of magnetic heads (3, 3') are mounted so as to protrude in the radial direction, and signals are recorded and reproduced on a magnetic tape (1) mounted in a spiral manner. a rotating drum (2) having a diameter substantially the same as that of the rotating drum (2);
A fixed drum (4) is provided on the same axis in close proximity to the magnetic tape (1) and has a step (22) for regulating the running position of the magnetic tape (1).
) of a magnetic recording/reproducing device comprising:
In 4), the fixed drum (4) has a magnetic tape (1) on its outer periphery.
A head drum (1) of a magnetic recording/reproducing device characterized by having a notch opening (26) near an entry point.
4).