JPH0786970B2 - Rotating head cylinder device - Google Patents

Description

The present invention relates to a rotary head cylinder device in a helical scan type magnetic recording / reproducing device such as an R-DAT, VTR.

[Conventional technology]

The helical scan type magnetic recording / reproducing apparatus is provided with a rotary head cylinder device including a rotary cylinder having a magnetic head mounted thereon and a fixed cylinder having a tape lead. Recording and reproduction of a signal is performed by slantingly contacting a predetermined angle with a cylinder surface) for traveling, and rotating a rotating cylinder so that a magnetic head scans a magnetic tape diagonally. .

In such a rotary head cylinder device, in order to prevent sticking of the magnetic tape to the cylinder surface due to the addition of a large tension to the magnetic tape, conventionally, an air film, that is, a space between the cylinder surface and the magnetic tape, that is, , Measures are taken to obtain an air layer. As an example of this means, in Japanese Patent Laid-Open No. 61-175955, a plurality of annular grooves are provided on the outer circumference of the rotary cylinder so that the diameter of the rotary cylinder is smaller than that of the fixed cylinder. Is disclosed. As a result, the amount of the air layer on the tape inlet side and the tape outlet side of the rotary head cylinder device is moderated, the magnetic head and the magnetic tape on the tape inlet side are in good contact with each other, and the spacing loss is suppressed. The magnetic tape is prevented from being damaged due to the contact between the fixed cylinder and the magnetic tape on the output side, and the increase in the load on the motor due to the sticking of the magnetic tape to the rotating cylinder at the time of startup is prevented.

[Problems to be Solved by the Invention]

By the way, the air layer generated between the cylinder surface and the magnetic tape changes depending on the rotation speed of the rotary cylinder, and when the rotation speed decreases, the amount of the air layer also decreases. This is because the rotation of the rotary cylinder causes air to be drawn between the cylinder surface and the magnetic tape to form an air layer, but when the number of rotations decreases, the amount of drawn air also decreases, and as a result, The amount of air layer is reduced.

Therefore, when the rotation speed of the rotating cylinder decreases due to external disturbance, the amount of air layer decreases and the magnetic tape may stick to the cylinder surface. , Excessive load will be applied to the motor. In particular, R-DAT with a small tape wrap angle
In the case of, in the review (reverse playback), the magnetic tape is run at a high speed in the opposite direction in order to search for the space between songs while playing the sound.
In this review mode, the relative speed between the magnetic tape and the magnetic head is set to be the same as during recording so that audio can be played back.For this reason, the rotation speed of the rotating cylinder must be reduced. I have to. Therefore,
In this review mode, a sufficient air layer is not formed and the magnetic tape may stick to the cylinder surface.

In the above conventional technique, a plurality of grooves are provided on the outer peripheral surface of the rotary cylinder so that a good air layer is formed between the magnetic tape and the cylinder surface. However, a good air layer is formed. Is when the rotating cylinder is rotating at high speed,
When the rotary cylinder rotates at a low speed, the air supply between the magnetic tape and the cylinder surface is also weakened, and the amount of the air layer is reduced, which may cause sticking of the magnetic tape. Also, by providing the groove on the rotary cylinder, the area of sticking of the magnetic tape on the cylinder surface is reduced, so the load on the motor at the time of startup is reduced by that amount, but this sticking area is still quite large. About
The load on the motor at start-up will also be quite large.

An object of the present invention is to solve the above problems and provide a rotary head cylinder device in which a sufficient air layer is formed irrespective of the number of rotations of the cylinder and stable tape running can be realized.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention provides an annular protrusion on the outer peripheral surface of a rotating cylinder having a magnetic head so as to extend over the entire circumference and come into contact with a magnetic tape.

[Action]

The magnetic tape is always in contact with the annular protrusion provided on the rotating cylinder regardless of the number of rotations of the rotating cylinder and even when the rotating cylinder is stopped. An air layer is formed between the lifted cylinder and the rotating cylinder.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing an embodiment of a rotary head cylinder device according to the present invention, and FIG. 2 is a partial cross-sectional view taken along the radial direction thereof, in which 1 is a rotary head cylinder device, 2 is a rotary cylinder, and 3 is a rotary cylinder. A fixed cylinder, 4 is a magnetic head, 5 is a tape lead, 6 is a magnetic tape, and 7 is an annular protrusion.

In FIGS. 1 and 2, a rotary head cylinder device 1 comprises a rotary cylinder 2 having a magnetic head 4 mounted thereon and a fixed cylinder 3, and the magnetic head 4 is provided between the rotary cylinder 2 and the fixed cylinder 3. A predetermined amount is projected outside from the gap. On the outer peripheral surface of the fixed cylinder 3, tape leads 5 are provided obliquely over a predetermined range, along which the magnetic tape 6 runs in the direction of arrow A. The rotating cylinder 2 is rotating in the same direction as the running direction of the magnetic tape 6 as indicated by an arrow B, and the rotation causes the magnetic head 4 to come into contact with the magnetic tape 6 for scanning to record and reproduce signals. Be done.

The rotary cylinder 2 has a diameter slightly smaller than that of the fixed cylinder 3, and a rib-shaped annular projection 7 is provided on the outer peripheral surface thereof over the entire circumference. The height of the annular projection 7 is equal to or less than the amount of protrusion of the magnetic head 4 from the outer peripheral surface of the rotary cylinder 2, and the width thereof is set to be about the width of the magnetic head 4, and at least the magnetic tape 6 contacts. Is preferably provided at a position where the magnetic tape 6 comes into contact with the magnetic tape 6 from the tape insertion side over a half length of the entire length where the magnetic tape 6 comes into contact with the cylinder surface.

Therefore, the magnetic tape 6 is always in contact with the annular projection 7, and therefore the magnetic tape 6 is prevented by the annular projection 7 regardless of the number of rotations of the rotary cylinder 2 and even when the rotary cylinder 2 is stopped. Is lifted from the outer peripheral surface of the rotary cylinder 2, and an air layer is always formed.

Therefore, as shown in FIG. 3, the magnetic tape 6 is pulled out from the tape cassette 8 to form a tape traveling path, the magnetic tape 6 travels in the forward direction indicated by the arrow A, and the rotary cylinder 2 becomes the magnetic tape 6. When the tape is rotated in the same direction as indicated by the arrow B, the rotation of the rotary cylinder 2 causes air to be fed in at the tape entrance side as indicated by the arrow C.
As shown in FIG. 2 and FIG. 2, the magnetic tape 6
Since the air is lifted from the cylinder surface by the annular projection 7, the air sent from the tape entrance side easily enters between the magnetic tape 6 and the cylinder surface, and an air layer is formed between them.

For this reason, even if the rotation speed of the rotary cylinder 2 is reduced as in the review mode, the air sent by this rotation smoothly enters between the magnetic head 6 and the cylinder surface, and even in this case, it is possible to be sure. An air layer will be formed. Further, even when the motor is started, since the magnetic tape 6 and the cylinder surface are separated from each other on the tape entry side, the rotary cylinder 2 rotates and air is sent between the magnetic tape 6 and the cylinder surface, so that the air layer This reduces the load on the motor.

〔The invention's effect〕

As described above, according to the present invention, an air layer can be reliably formed between the magnetic tape and the cylinder surface regardless of the number of rotations of the rotary cylinder, and the magnetic tape can be formed on the cylinder surface. The excellent effect of preventing sticking and realizing stable tape running can be obtained.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a rotary head cylinder device according to the present invention, FIG. 2 is a partial sectional view taken along the radial direction thereof, and FIG. 3 is a tape running path of an example of a helical scan type magnetic recording / reproducing device. FIG. 6 is a diagram showing the feeding of air by rotation of a rotating cylinder. 2 ... Rotating cylinder, 3 ... Fixed cylinder, 4 ... Magnetic head, 5 ... Tape lead, 6 ... Magnetic tape, 7 ...
… An annular protrusion.

Claims (1)

[Claims] 1. A rotating head cylinder device comprising a rotating cylinder having a magnetic head and a fixed cylinder having a tape lead, wherein the rotating cylinder has an outer peripheral surface extending once around the outer peripheral surface and the outer periphery of the rotating cylinder and the fixed cylinder. A rotary head cylinder device, characterized in that an annular projection is provided so as to come into contact with a traveling magnetic tape while obliquely contacting a surface thereof.