JPH0453055A - Rotary head drum device - Google Patents

Abstract

PURPOSE:To reduce the sound of patting a head chip and impact jitter by reducing the amount of protruding a head with a lower drum as a reference by reducing the difference of the diameters between upper and lower drums at the parts of starting and ending the tape winding. CONSTITUTION:The rotary head drum device is composed of a magnetic head 4, rotary upper drum 1 and fixed lower drum 2, and a tape 3 guided by a tape guide 5 is wound around the upper and lower drums and fed out by a tape guide 6. At the part of starting and ending the tape winding, the difference of the diameters between the upper and lower drums is small, and the amount of protruding the head with the lower drum as the reference is small as well. Therefore, the sound of patting the head chip and the impact jitter are reduced. At the middle part of winding the tape, the difference of the diameter is made maximum. Therefore, force Ft in tape breadthwise direction is enlarged, the tape is pressed onto a lead, and the floating-up or the fluctuation of the tape in the breadthwise direction on the lead is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary head drum device used in a recording/reproducing device such as a video tape recorder.

[Conventional technology]

For faithful signal reproduction, it is necessary for the head to scan without leaving the recording track, and especially in compatible reproduction, it is necessary to minimize track curvature. To this end, lifting and fluctuation of the tape in the width direction on the leads must be suppressed as much as possible.

Therefore, the conventional device is, for example,
As described in the above publication, by providing a diameter difference between the upper drum and the lower drum, lifting and fluctuation in the width direction on the tape lead can be suppressed.

The effect at this time is shown in Figure 2a). Figure 2 a) shows a side cross section of the tape winding section, and when the tape 3 is wound around the upper drum 1 and the lower drum 2, there is a diameter difference between the upper drum 1 and the lower drum 2, It can be wrapped diagonally with Drum 2@. It is assumed that the tape 3 is wound around the upper drum and the lower drum 2 with a force F due to its tension. The force F is decomposed into a force Ft in the tape width direction and a force Fn in a direction perpendicular to the tape width direction. The tape 3 is pressed against the lead by the force Ft in the tape width direction, and lifting or fluctuation of the tape 3 on the lead in the width direction is suppressed.

[Problem to be solved by the invention]

The above conventional technology does not take into account the fact that the difference in diameter increases the amount of head protrusion when looking at the lower drum as a reference, and the head tip does not wrap around the tape at the starting point or at the end of the winding. (e) The sound generated when the tape touches and leaves the tape at the end, and (e) the increase in so-called impact jitter, which is caused by the increase in head chip hitting noise and the vibration of the tape in its longitudinal direction at this time. There was a problem.

An object of the present invention is to reduce head tapping sound and impact jitter while maintaining the effect of reducing track bending.

[Means to solve the problem]

In order to achieve the above object, in the present invention, the outer diameter of the lower drum is made smaller than the outer diameter of the upper drum, thereby creating a diameter difference between the two drums. In particular, in order to maximize the diameter difference in the middle part of the winding, make sure that the difference in diameter is smaller at the start part of the winding, and at the end part of the winding, compared to the middle part of the winding.

[Effect]

In the rotary head drum device according to the present invention, the diameter difference between the upper drum and the lower drum is reduced at the tape winding start portion and the tape winding end portion. The amount of increase in the amount of head protrusion compared to the standard becomes smaller. As a result, increases in head chip knocking noise and impact jitter are reduced.

Here, at the beginning of tape winding and the end of tape winding, tape guides provided immediately before and after the tape winding are used to guide the tape to the rotating head drum device.
Since it is possible to suppress lifting and fluctuation in the width direction of the tape lead 2, the diameter difference may be small.

On the other hand, in the middle of the winding, W, H6 and the tape guide immediately after cannot suppress the lifting and fluctuation in the width direction on the tape lead, so by providing a large diameter difference, lifting and fluctuation in the width direction can be suppressed. be done.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a rotary head drum device of a video tape recorder, particularly a top rotary type drum, will be described with reference to the drawings.

The rotary head drum device according to the present invention, as shown in FIG. 1a), consists of a rotating soil drum 1 having a magnetic head 4 and a fixed lower drum lλ2. A pair of tape guides 5 and 6 are installed on the input and output sides of the drum device, and the tape 3 that enters the tape input side by one tape guide 5 is
It is wound around the upper drum 1 and the lower drum 2 and guided by the other tape guide 6 from the tape exit side.

The outer diameter of the lower drum 2 is as indicated by the broken line in Figure 1b).
The diameter difference is maximum at the middle of the tape winding, and the diameter difference becomes smaller at the beginning of the tape winding and at the end of the winding compared to the middle of the winding.6 As shown in Figure 2 a), at the middle of the tape winding, The diameter difference between the upper drum 1 and the lower drum 2 is the largest, and the amount of head protrusion when looking at the lower drum 2 as a reference is large. As shown in Figure 2b), at the beginning of tape winding and at the end of tape winding, the difference in diameter between upper drum 1 and lower drum 2 is smaller than in the middle of winding, and when viewed from lower drum 2 as a reference. The amount of head protrusion is small.

As a result, head tapping noise and impact jitter are reduced.

Here, at the beginning of tape winding and the end of winding, in order to guide the tape 3 to the rotating head drum device,
The tape guides 5.6 provided immediately before and after the lead can prevent the tape 3 from rising or fluctuating in the width direction on the lead, so the difference in diameter may be small.

On the other hand, in the middle part of the winding, the tape guides 5 and 6 immediately before and after the tape 3 have a floating position in the width direction on the lead.
Since it is not possible to suppress warpage and fluctuation, by providing a large diameter difference, lifting and fluctuation in the width direction can be suppressed.

As another embodiment, as shown in FIG. 3, the present invention may be applied to a rotary head drum device consisting of a fixed "nidrum", a rotary magnetic head 7, and a fixed lower drum 2, a so-called medium rotation type drum.

l Also in this case, a diameter difference is created by making the outer diameter of the lower drum 2 smaller than the outer diameter of the upper drum 1, and the diameter difference is maximum at the middle of the tape winding, where the tape winding starts and the winding ends. The difference in diameter can be made smaller at the middle part of the winding compared to the middle part of the winding.

Regarding its effect, we will discuss the above and the upper rotation type drum set. The same is true.

〔Effect of the invention〕

According to the present invention, by reducing the difference in diameter at the beginning of tape winding and at the end of winding, it is possible to reduce the increase in the amount of protrusion of the head when viewed from the lower drum as a reference. This has the effect of reducing tapping noise and in-bug jitter.

Further, since a large diameter difference is provided near the middle of the winding, it is possible to suppress lifting and fluctuation in the width direction of the tape glue near the middle of the winding, and it is possible to maintain the effect of obtaining good tracking.

[Brief explanation of the drawing]

Fig. j a) is a perspective view of one embodiment of the present invention, Fig. 1 b) is a plan view of Fig. 1 a), and Fig. 2 a) is a side sectional view of the tape-wrapped middle part of Fig. 1 a). , FIG. 2 b) is a side sectional view of the starting part of the tape winding of FIG. 1 a), and FIG. 3 is a view showing another embodiment of the present invention. 1... Upper drum 2... Lower drum 3...-tape 5... Tape guide 6...- Tape guide agent Patent attorney Masaru Ogawa Ougi 1 Country 2nd mouth (α) (b) 4 To the tip of the stem・Y 5 Tape 0 is the point 6 Tape door ID ゛2T-”yitA 3-r-B

Claims (1)

[Claims] 1. An upper drum and a lower drum each having a cylindrical portion around which a tape is wound, a rotary head for recording information on the tape or reproducing information from the tape, and a rotary head that slides on the edge of the tape. A rotary head drum device comprising: a tape guide portion that is in contact with the tape guide portion and guides the running of the tape; , a rotary head drum having a configuration in which the diameter difference between the outside dimension of the cylindrical portion of the upper drum and the outer dimension of the upper drum is maximized at a substantially central portion in the tape length direction of the portion around which the tape is wound. Device.